US20070137567A1 - Apparatus for manufacturing a semiconductor device - Google Patents

Abstract

An apparatus for manufacturing a semiconductor device, including a process chamber which holds a substrate to be subjected to a prescribed process, a gas inlet pipe which introduces a process gas into the process chamber, a gas outlet pipe which discharges the gas from the process chamber to outside the process chamber, component-measuring devices which measure components of the gas in the process chamber or at least two different gases, concentration-measuring devices which measure concentration of each component of the gas in the process chamber, or the concentration of each component of at least two different gases, and a control device which adjusts the components of the process gas, the concentration of each component of the process gas and an atmosphere in the process chamber, on the basis of values measured by the component-measuring device and concentration-measuring device.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• This is a division of application Ser. No. 11/204,079, filed Aug. 16, 2005, which is a division of application Ser. No. 10/424,906, filed Apr. 29, 2003 (now U.S. Pat. No. 6,946,304), which are incorporated in their entirety herein by reference. U.S. application Ser. No. 10/424,906 is a Continuation Application of PCT Application No. PCT/JP02/07206, filed Jul. 16, 2002, which was not published under PCT Article 21(2) in English.
• This application is also based upon and claims priority from prior Japanese Patent Application No. 2001-264867, filed Aug. 31, 2001, the entire contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
• 1. Field of the Invention
• The present invention relates to an apparatus for and method of manufacturing a semiconductor device, and a cleaning method for use in the apparatus for manufacturing a semiconductor device. Particularly, the invention relates to an apparatus for and method of manufacturing a semiconductor device, which are designed to perform hot processes, such as thermal oxidation, annealing, CVD and RTP, in manufacturing the semiconductor device, and also to a cleaning method for use in the apparatus for manufacturing a semiconductor device.
• 2. Description of the Related Art
• In processes of manufacturing a semiconductor device, the steps of forming thin films on the semiconductor substrate (wafer) are very important. Each film-forming step utilizes thermal reaction, chemical reaction or the like between a feed gas and silicon, i.e., the representative material of the wafer, and a feed gas, or between various feed gases. So-called “hot processes,” such as thermal oxidation, thermal nitriding, annealing, rapid thermal process (RTP), and chemical vapor deposition (CVD), are particularly important.
• Generally, these steps are carried out by introducing feed gases into the reaction furnace of a film-forming apparatus, in which one or more silicon wafers, i.e., semiconductor substrates, have been placed. To form films of desired properties (e.g., thickness, composition, resistance, etc.), the flow rates of the feed gases, the pressure and temperature in the reaction furnace and the processing time are preset. A controller controls the film-forming apparatus, causing the apparatus to operate in accordance with the preset values. In recent years, the internal microstructure of semiconductor devices has grown remarkably complex and acquired high component concentration. It is therefore very important to form high-quality thin films so that the semiconductor device that is a complicated and high-performance device may operate reliably in stable conditions. To this end, it increasing necessary to control, with very high precision, the various parameters (film-forming parameters) including the flow rates of feed gases, the pressure and temperature in the reaction furnace and the process time, all mentioned above.
• As has been pointed out, it has become more necessary to control, with high accuracy, the film-forming parameters applied in the film-forming step in order to provide high-quality thin films. With ordinary film-forming apparatuses, however, some of the film-forming parameters cannot be controlled with so high a precision as desired, even if the controller for controlling the film-forming parameters is improved in terms of control ability.
• A thermal oxidation process may be repeated several times (in several runs). In this case, the film-forming conditions are set so that a film may be formed each time (in each run) at the same conditions, such as oxidation temperature, flow rate of oxygen and pressure of oxygen. Theoretically, any thin film formed at one time should have almost the same thickness as the thin film formed at any other time. In practice, however, a difference in thickness, which cannot be neglected or allowed, may exist between the thin film formed in one run and the thin film formed in any other run.
• Some reasons for this difference in thickness can be considered. For example, the partial pressure that the oxidizer assumes in the oxidization furnace may varies from run to run, due to any factor other than the flow rate of the oxygen being introduced into the oxidation furnace and the pressure of the oxygen introduced in the oxidation furnace. More specifically, if the process using water is performed in one run, some of the water may remain adsorbed in the furnace, not purged from the reaction furnace before the next run. In this case, the water acts as an oxidizer in the furnace. The oxide film formed while the water remains in the furnace is inevitably thicker than the film formed in a film-forming step at which water scarcely exists in the furnace.
• In any film-forming apparatus that has a reaction furnace the interior of which is exposed to the atmosphere, the water in the atmosphere is taken into the reaction furnace when a wafer is brought into the furnace for each run. If so, the temperature in the furnace may differ from run to run, because the water concentration (humidity) in the atmosphere is not always the same at the start and end of any run.
• The amount of the water adsorbed in the reaction furnace or of the water taken from the atmosphere into the furnace is extremely unstable. That is, it changes very much. Therefore, the amount of the water adsorbed or taken into the furnace is not set as a controllable parameter in the ordinary film-forming apparatuses. Even if the amount of the water is set as a film-forming parameter, oxide films may greatly differ in thickness so long as the apparatus that forms them performs a film-forming process using water or has a reaction furnace whose interior is exposed to the atmosphere.
• A method many be devised, in which any very unstable factor, such as the amount of water outside the furnace, is not used as a film-forming parameter and a factor such as the components of the exhaust gas discharged from the furnace and containing feed gas used in the film-forming step is analyzed (measured, observed and monitored). Thus, the state of gas and the atmosphere, both in the furnace, during the film-forming step may be determined and then controlled to be appropriate ones. In this method, however, neither the state of gas nor the atmosphere in the furnace is accurately monitored.
• This is because the component, concentration and the like of the feed gas introduced into the reaction furnace may largely differ from those the feed gas assumes outside the reaction furnace. That is, the components, concentration and the like of the feed gas may have different values each, before, during and after the film-forming step, depending on the thermal or chemical reaction that takes place during the film-forming step. Particularly, the more reactive or decomposable the feed gas is, the more greatly its components, concentration, etc. vary with time. Further, the composition, concentration and the like of the feed gas, thus analyzed, may greatly differ, depending upon the positions of the analyzers employed to analyze them.
• The thickness of the film differs, from run to run, probably because of the residual feed gas accumulated in the reaction furnace. For example, the components of the feed gas fail to be reacted completely in one run and may adhere to the inner surface of the reaction furnace and may be solidify. When the next run is performed in this condition, any solid component of the gas, on the inner surface of the furnace, changes to gas due to the heat in the reaction furnace. In the next run, this gas mixes with the feed gas newly supplied into the reaction furnace. Consequently, the amount of feed gas in the reaction chamber increases over the constant value for each run. In other words, the amount of feed gas differs, from run to run. It follows that the thickness of the film varies, from run to run. The more runs are carried out, the more residue of the feed gas will likely be accumulated in the reaction furnace. This phenomenon is prominent in proportion to the number of runs carried out.
• One film-forming apparatus may perform different film-forming steps. In this case, the material used to form a film differs from step to step. If the components of the material used in one film-forming step remain not completely reacted in the reaction furnace, it may be mixed with the feed gas in the next film-forming step, though it is unnecessary in the next step. If this component is mixed, the thin film formed in the next step may have not only a thickness greatly differing from the design value, but also properties totally undesired or extremely poor.
BRIEF SUMMARY OF THE INVENTION
• According to an aspect of the invention, there is provided an apparatus for manufacturing a semiconductor device. The apparatus comprises: a process chamber which holds a substrate to be subjected to a prescribed process; a gas inlet pipe which is connected and communicates with an interior of the process chamber and which introduces a process gas for use in the process, into the process chamber; a gas outlet pipe which is connected and communicates with the interior of the process chamber and which discharges the gas from the process chamber to outside the process chamber; component-measuring devices which are provided at two or more positions selected from the group comprising of a position in the process chamber, a position in the gas inlet pipe and a position in the gas outlet pipe, and which measure components of the gas in the process chamber or at least two different gases selected from the group comprising of gas in the process chamber, gas to be introduced into the process chamber and gas discharged from the process chamber; concentration-measuring devices which are provided at two or more positions selected from the group comprising of a position in the process chamber, a position in the gas inlet pipe and a position in the gas outlet pipe, and which measure concentration of each component of the gas in the process chamber, or the concentration of each component of at least two different gases selected from the group comprising of the gas in the process chamber, the gas to be introduced into the process chamber and the gas discharged from the process chamber; and a control device which adjusts the components of the process gas, the concentration of each component of the process gas and an atmosphere in the process chamber, on the basis of values measured by the component-measuring device and concentration-measuring device, such that an appropriate process is performed on the substrate.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
• FIG. 1 is a schematic diagram showing the structure of a film-forming apparatus that is an apparatus for manufacturing a semiconductor device, according to the first embodiment of the present invention;
• FIG. 2 is a graph explaining a method of determining the gas concentration in the reaction furnace provided in the film-forming apparatus shown inFIG. 1;
• FIG. 3 is a schematic diagram illustrating the structure of a film-forming apparatus of wet oxidation type, which is an apparatus for manufacturing a semiconductor device, according to the second embodiment of this invention;
• FIG. 4 is a schematic diagram depicting the structure of a film-forming apparatus that is an apparatus for manufacturing a semiconductor device, according to the third embodiment of the invention;
• FIG. 5 is a schematic diagram showing the structure of a film-forming apparatus of batch type that is an apparatus for manufacturing a semiconductor device, according to the fourth embodiment of this invention;
• FIG. 6 is a schematic diagram illustrating the structure of a film-forming apparatus that is an apparatus for manufacturing a semiconductor device, according to the fifth embodiment of the invention; and
• FIG. 7 is a graph explaining a method of determining the gas concentration in the reaction furnace provided in the film-forming apparatus shown inFIG. 6.
DETAILED DESCRIPTION OF THE INVENTION
• Embodiments of the invention will be described in detail with reference to the accompanying drawings.
FIRST EMBODIMENT
• First, the apparatus for manufacturing a semiconductor device, method of manufacturing a semiconductor device and cleaning method for use in the apparatus, all according to the first embodiment of the invention, will be described with reference toFIG. 1 and2.
• FIG. 1 is a schematic diagram depicting the structure of theapparatus1 for manufacturing a semiconductor device, according to the first embodiment.FIG. 2 is a graph explaining a method of determining the gas concentration at a predetermined position in theprocessing chamber3 that is provided in theapparatus1 shown inFIG. 1.
• AsFIG. 1 shows, theapparatus1 for manufacturing a semiconductor device, according to this embodiment, comprises aprocess chamber3, agas inlet pipe5,gas outlet pipe6, component-measuring devices7, concentration-measuring devices8, acontroller9, and the like. Theprocess chamber3 may hold asubstrate2 to be subjected to a specific process. Thegas inlet pipe5 introduces aprocess gas4 into theprocess chamber3. Thegas outlet pipe6 exhausts gas from theprocess chamber3. One component-measuring device7 is provided on thegas inlet pipe5 to measure the components of the process gas being introduced into theprocess chamber3. One concentration-measuring device8 is provided on thegas inlet pipe5, too, to measure the concentration of each component of theprocess gas4 being introduced into thechamber3. The other component-measuring device7 is provided on thegas outlet pipe6 to measure the components of the gas being exhausted from theprocess chamber3. The other concentration-measuring device8 is provided on thegas outlet pipe6, too, to measure the concentration of each component of the gas being exhausted from thechamber3. Thecontroller9 controls the components of theprocess gas4, the concentration of each component of thegas4 and the atmosphere in theprocess chamber3, in accordance with the values measured by the component-measuring devices7 and concentration-measuring devices8. Thus, an appropriate process may be performed on thesubstrate2.
• The apparatus for manufacturing a semiconductor device, according to this embodiment, is a film-formingapparatus1 of so-called “single-wafer processing type.” Namely, this apparatus forms films on onewafer2, i.e., the substrate held in theprocess chamber3 and being processed.
• Outside thereaction furnace3, or process chamber, a plurality ofheaters10 are provided. They function as a temperature-adjusting device that sets the temperature in thereaction furnace3 at a predetermined value. Athermometer11 and apressure gauge12 are attached to thereaction chamber3. Thethermometer11 measures the temperature in thefurnace3. Thepressure gauge12 measures the pressure in thefurnace3.
• Thegas inlet pipe5 is connected to thereaction furnace3 and communicates with the interior of thefurnace3. Thepipe5 has agas inlet port13 at the end that communicates with the interior of thefurnace3. Theport13 guides theprocess gas4 from thegas inlet pipe5 into thereaction furnace3. Thus, theprocess gas4 is introduced into thereaction furnace3 through thegas inlet port13 after passing through thegas inlet pipe5.
• As a one-dot dashed line indicates inFIG. 1, mass-flow controllers14 are connected to one end of thegas inlet pipe5, which is connected at the other end to thereaction furnace3. The mass-flow controllers14 are provided, each serving as a feed-supplying device for supplying oneprocess gas4 into thegas inlet pipe5. In this embodiment, three feed gases A, B and C are used asprocess gases4. Hence, the embodiment has three mass-flow controllers14a,14band14c. The first mass-flow controller14asupplies the first feed gas A. The first mass-flow controller14bsupplies the first feed gas B. The third mass-flow controller14csupplies the first feed gas C.
• A component-measuring device7 and a concentration-measuring device8 are connected to that part of thegas inlet pipe5, which lies upstream of the gas flow indicated by a broken line inFIG. 1, with respect to thegas inlet port14. The component-measuring device7 monitors the components of the process gas being introduced into thereaction chamber3. The concentration-measuring device8 monitors the concentration of each component of theprocess gas4 being introduced into thechamber3. The component-measuring device7 and the concentration-measuring device8, both connected to thegas inlet pipe5, are formed integral with each other in the present embodiment. More specifically, the devices7 and8 constitute a mass analyzer that can measure the components of theprocess gas4 and the concentration of each gas component at the same time. The mass analyzer, which measures the components of theprocess gas4 being introduced into thereaction furnace3 and the concentration of each component of theprocess gas4, shall be referred to as “first mass analyzer15.”
• More precisely, the first mass analyzer15 can measure, at the same time, the composition of theprocess gas4 composed of feed gases A, B and C and being introduced into thereaction furnace3, and the concentrations, or contents (composition ratios), of the feed gases A, B and C.
• Thegas outlet pipe6 is connected to thereaction furnace3, communicating with the interior thereof, and lies downstream of the gas flow indicated by the broken line inFIG. 1, with respect to thegas inlet pipe5. Thewafer2 held in thereaction furnace3 is located between thegas inlet pipe5 and thegas outlet pipe6. Thegas outlet pipe6 has agas outlet port16 at the end that communicates with the interior of thereaction furnace3. Thegas outlet port16 guides gases from inside thereaction furnace3 into thegas outlet pipe6. Thus, the gases are discharged from thereaction furnace3 first through thegas outlet port16 and then through thegas outlet pipe6.
• Aswitch valve17 and anexhaust pump18 are provided on that part of thegas outlet pipe6, which is remote from the junction of thepipe6 and thereaction furnace3. Theswitch valve17 andexhaust pump18 are operated and stopped, to discharge the gases from thereaction furnace3 via thegas outlet pipe6. In this embodiment, theswitch valve17 functions as a pressure control valve to maintain the pressure in thereaction furnace3 at a preset value while theexhaust pump18 is operating and at another preset value while thepump18 remains stopped.
• A component-measuring device7 and a concentration-measuring device8 are connected to that part of thegas outlet pipe6, which lies near thegas outlet port16 and upstream of the gas flow indicated by a broken line inFIG. 1, with respect to thegas outlet port16. The component-measuring device7 monitors the components of the gas discharged from thereaction chamber3. The concentration-measuring device8 monitors the concentration of each component of the gas discharged from thechamber3. The component-measuring device7 and the concentration-measuring device8, both connected to thegas outlet pipe6, are formed integral with each other in the present embodiment, like the devices7 and8 connected to thegas inlet pipe5. More correctly, the devices7 and8 constitute a mass analyzer that can measure the components of the gas discharged from thereaction furnace3 and the concentration of each gas component at the same time. The mass analyzer, which measures the components of the gas discharged from thereaction furnace3 and the concentration of each component of the gas, shall be referred to as “second mass analyzer19.”
• To be more specific, the second mass analyzer19 can measure, at the same time, the composition of the gas (exhaust gas) discharged from thereaction furnace3 and the concentrations, or contents (composition ratios), of the components of the exhaust gas. Note that the exhaust gas is composed ofprocess gas4 that has been introduced into thereaction furnace3 but not used in the film-forming reaction,process gas4 that has been introduced into thereaction furnace4 and contributed to the film-forming reaction,process gas4 that has been used in the film-forming reaction, and the like.
• As described above, in the film-forming apparatus according to the first embodiment, the first mass analyzer15 and the second mass analyzer19 are provided at the upstream and downstream sides of thewafer2 held in thereaction furnace3. Namely, the mass analyzers15 and19 are located upstream and downstream, respectively, with respect to the gas that flows in thereaction furnace3, from thegas inlet pipe5 to thegas outlet pipe6 as is indicated by the broken line inFIG. 1.
• Thecontroller9, used as a control device, is connected to theheaters10,thermometer11,pressure gauge12, first to third mass-flow controllers14a,14band14c, first mass analyzer15, second mass analyzer19,switch valve17,exhaust pump18, and the like. The solid-line arrows shown inFIG. 1 indicate the directions in which electric signals flow between the devices connected to thecontroller9. InFIG. 1, the first to third mass-flow controllers14a,14band14care depicted as a single mass-flow controller14, thus simplifying the figure. Thecontroller14 receives and transmits signals from and to thecontroller9, so that thecontroller9 may control thecontrollers14a,14band14c. In fact, however, the first to third mass-flow controllers14a,14band14cexchange signals with thecontroller9, each independently of the other mass-flow controllers. Hence, thecontroller9 controls each mass-flow controller, independently of the two other mass-flow controllers.
• Thecontroller9 is designed to determine with high precision the conditions in which a thin film is being formed, from the signals sent from thethermometer11,pressure gauge12, first to third mass-flow controllers14a,14band14c, first mass analyzer15, second mass analyzer19, and the like.
• A plurality of process parameters of various types has been given to thecontroller9. They are optimal for controlling the components of theprocess gas4, the concentration of each component of thegas4, temperature and pressure in thereaction furnace3 and condition of forming a film. Hence, the film can be formed on thewafer2 in optimal conditions. In other words, the process parameters set the best possible conditions (i.e., actual environment) for forming a film on thewafer2, to manufacture a semiconductor device that has thin films of the quality desired.
• The process parameters can be obtained by, for example, experiments or computer simulations. In the film-formingapparatus1 of this embodiment, the process parameters are stored in a process-parameter database unit20 indicated by two-dot dashed line inFIG. 1. The more process parameters the process-parameter database unit20 stores, the more accurately can the components of theprocess gas4, concentration of each component of thegas4, temperature and pressure in thereaction function3 and condition of forming a film be controlled to optimal ones.
• Thethermometer11 and thepressure gauge12 measure the temperature and pressure in thereaction furnace3 at prescribed time intervals. They generate electric signals representing the values they have measured (i.e., measured value data), which are sent to thecontroller9. After receiving these electric signals, thecontroller9 adjusts the operating conditions of theheaters10,switch valve17,exhaust pump18 and the like to appropriate ones in accordance with the process parameter already given to it. The film-forming process may therefore be performed on thewafer2 in optimal conditions.
• Thecontroller9 incorporated in the present embodiment is designed to control the components of theprocess gas4 and the concentration of each component of thegas4 to proper value, on the basis of the gas components and gas component concentrations (i.e., measured value data) that the first mass analyzer15 and second mass analyzer19 have measured at the positions they are located. Thus, the film-forming process can be carried out on thewafer2 in appropriate conditions. Thecontroller9 used in this embodiment is designed, also to utilize the preset data, such as the flow rates and flow speeds of the feed gases A, B and C, as data for appropriately controlling the components of theprocess gas4 and the concentration of each component of thegas4.
• The first mass analyzer15 and second mass analyzer19 measure the gas components and gas component concentrations, at the positions they are located and at predetermined time intervals. They generates electric signal representing the values measured (i.e., measured value data). The electric signals are supplied to thecontroller9. Thecontroller9 receives electric signals also from the first to third flow-mass meters14a,14band14c. Thecontroller14ameasures the flow rate and flow speed of the feed gas A flowing through it, thecontroller14 measures the flow rate and flow speed of the feed gas B, and thecontroller14ameasures the flow rate and flow speed of the feed gas C flowing through it, each at different time intervals. The first tothird controllers14a,14band14cgenerate electric signals (i.e., preset data) that represent the flow rates and flow speeds of the gases A, B and C. These signals are sent to thecontroller9. Upon receipt of the signals, thecontroller9 adjusts the operating conditions of the first to third mass-flow controllers14a,14band14con the basis of the process parameters it already has, so that the film-forming process may be performed on thewafer2 in appropriate conditions. Namely, thecontroller9 adjusts the flow rates and flow speeds of the feed gases A, B and C flowing through the mass-flow controllers14a,14band14cin accordance with the process parameters, to appropriate values whenever necessary. Thus, the film-forming process may be carried out on thewafer2 in appropriate conditions.
• Thecontroller9 is configured to control the condition of forming a film, in accordance with the process parameters, thereby to perform the film-forming process on thewafer2 in appropriate conditions. More precisely, thecontroller9 can set the time of the film-forming process at a predetermined value, which is required until a semiconductor device having thin films of desired quality, in accordance with the process parameters.
• Moreover, in the film-formingapparatus1 according to this embodiment has a component-calculatingunit21 and a concentration-calculatingunit22. The component-calculatingunit21 calculates, from the gas components (measured data) measured by the first and second mass analyzers15 and19, the components that the gas has at a predetermined position in thereaction furnace3 and at the same time the analyzers15 and19 measure the components of the gas. The concentration-calculatingunit22 calculates, from the component concentration (measured data) measured by the analyzers15 and19, the concentration that each gas component has at said position in thereaction furnace3 and at the same time the analyzers15 and19 measure the concentration of the gas component. The component-calculatingunit21 and concentration-calculatingunit22 are designed to calculate the components that the gas has at the predetermined position in thereaction furnace3 and the concentration each gas component has at the predetermined position, at prescribed time intervals as the first and second mass analyzers15 and19 do operate. In the film-formingapparatus1 of the present embodiment, the component-calculatingunit21 and concentration-calculatingunit22 are incorporated in thecontroller9, as may be indicated by two-dot dashed lines inFIG. 1.
• A calculation model for finding the concentration that one component of the gas has at the predetermined position in thereaction furnace3 will be explained, with reference toFIG. 2. In the film-formingapparatus1 according to this embodiment, the first mass analyzer15 provided near thegas inlet port13 monitors the components of the gas and the concentration of each gas component, and the second mass analyzer19 provided near thegas outlet port16 monitors the components of the gas and the concentration of each gas component. In this case, the simplest calculation model may be used to find the concentration of one gas component in the form of an interpolated value on a linear function (straight line) that connects two values measured by the first and second mass analyzers15 and19, respectively.
• During the film-forming process, however, the components that the gas has at the predetermined position in thereaction furnace3 and the concentration that each gas component has at the predetermined position are too complex to be expressed as a linear function as mentioned above. Therefore, a more complex calculation model should better be used in order to find more accurately the concentration of one gas component at the predetermined position in thereaction furnace3. This calculation model finds the concentration by interpolation, or by connecting the values measured by the first mass analyzer15 and second mass analyzer19 by a complex function (curve), as is indicated by the one-dot dashed lines inFIG. 1.
• The calculation models explained above are used in the same way in order to measure the components that the gas has at the predetermined position in thereaction furnace3.
• The calculation models for measuring the components the gas has at the predetermined position in thereaction furnace3 and the concentration of each gas component can be attained by, for example, computer simulations, just like the above-mentioned process parameters are obtained. Each calculation model is assumed to be stored in the calculation-model database unit23 that is incorporated in thecontroller9 as indicated by the two-dot dashed lines inFIG. 1. The more calculation models the calculation-model database unit23 stores, the more accurately the components the gas has at the predetermined position in thereaction furnace3 and the concentration each gas component has will be measured as interpolated values during the film-forming process.
• Thecontroller9 provided in this embodiment is designed to update the process parameters at the prescribed time intervals, even during the film-forming process, in accordance with the gas components at the predetermined position in thereaction furnace3 and the concentration of each gas component, which the component-calculatingunit21 and concentration-calculatingunit22 calculate. Hence, the film-forming process can be performed on thewafer2 in appropriate conditions. On the basis of the process parameters thus updated, thecontroller9 controls the operating conditions of the above-mentioned devices, appropriately adjusting the components of theprocess gas4, the concentration of each component, the atmosphere in thereaction furnace3 and the conditions of the progressing film-forming process.
• Moreover, thecontroller9 calculates the difference between each process parameter updated on the basis of the values calculated by the component-calculatingunit21 and concentration-calculatingunit22, on the one hand, and the initial process parameter set at the start of the film-forming process, on the other hand. In accordance with the different, thecontroller9 changes (corrects) the temperature and pressure in thereaction furnace3, the flow rates and flow speeds of the feed gases A, B and C, the time of the film-forming process, and the like, to appropriate values. Hence, the film-forming process can be performed on thewafer2 in appropriate conditions. This makes it possible to provide a semiconductor device that has thin films of desired quality.
• The process parameters updated in accordance with the values calculated by the component-calculatingunit21 and concentration-calculatingunit22, and the difference between each updated process parameter and the initial process parameter set at the start of the film-forming process are stored into the process-parameter database unit20, every time the updating and calculation are carried out. Thus, the more times the film-formingapparatus1 performs the film-forming process, the more choices of appropriate conditions for the film-forming process. This renders it possible to carry out the film-forming process on thewafer2 at the best possible conditions. A semiconductor device having thing films of higher quality can, therefore, be obtained.
• Thecontroller9 used in the present embodiment can perform a plurality of preset sequences of film-forming process. It can therefore perform different types of film-forming processes on thewafer2, each in appropriate conditions. Further, thecontroller9 is configured to select and perform one of the sequences of film-forming process, which meets the conditions of the film-forming step that follows the film-forming step being carried out when the component-calculatingunit21 and concentration-calculatingunit22 make calculations. The conditions of the film-forming step that follows the film-forming step being carried out are that the next step is hardly influenced by the film-forming step now undergoing, so that the film-forming process may be performed on thewafer2 in appropriate conditions. The process sequence that satisfies such conditions is selected in accordance with the values calculated by the component-calculatingunit21 and concentration-calculatingunit22.
• The process sequences are stored in the process-sequence database unit24 that is provided in thecontroller9, as is indicated by two-dot dashed lines inFIG. 1. The greater the number (types) of process sequences stored in the process-sequence database unit24, the more appropriate the conditions will be, in which the film-forming process can be carried out to provide a semiconductor device that has thin films of higher quality.
• As described above, in the film-formingapparatus1 that is an apparatus for manufacturing a semiconductor device, which is the first embodiment of the invention, the gas components and the concentration of each gas component are directly monitored in real time at one position on the upstream of thewafer2 and at one position on the downstream of thewafer2, during the film-forming process being performed on thewafer2 held in thereaction furnace3. The components that the gas has and the concentration that each gas component has, at the predetermined positions in thereaction furnace3, are calculated in real time from the values thus monitored. Thereafter, the values calculated are fed back, in real time, to the conditions in which the film-forming process is being carried out, so that the film-forming process may be appropriately carried out on thewafer2. Hence, the film-forming process can be accomplished, while being appropriately controlled.
• With the film-forming apparatus I thus configured, the components that the gas has and the concentration that each gas component has, at the predetermined positions in thereaction furnace3, can be monitored in real time and with high precision. Additionally, thecontroller9 incorporated in the film-formingapparatus1 can accurately determine the conditions in which a thin film is being formed on thewafer2, from the signals sent from thethermometer11,pressure gauge12, first to third mass-flow controllers14a,14band14c, first mass analyzer15, second mass analyzer19 and the like. The process parameters (control parameters) can therefore be changed to appropriate values, if necessary in view of the conditions of forming the thin film, to perform the film-forming process on thewafer2 in appropriate conditions, regardless of the type of the film-forming process. This makes it easy to provide a semiconductor device that has thin films of desired quality.
• In the film-formingapparatus1 of the structure described above, the process parameters, the calculation model and the process sequence can be changed or selected by virtue of the real-time feedback control that thecontroller9 accomplishes in accordance with the gas components and the concentration of each gas component at the predetermined position in thereaction furnace3. Thus, the uncontrollable disturbance (uncontrollable factor or uncontrollable parameter), such as the amount of water introduced into thereaction furnace3 as explained in regard to the conventional technique, need not be used as a process parameter. Hence, the film-forming process can be reliably controlled, robust (or hardly susceptible) to such disturbance.
• A method of manufacturing a semiconductor device, according to the first embodiment of this invention, will be described. The method of manufacturing a semiconductor device, according to the first embodiment, is, to be specific, a film-forming method that uses the film-formingapparatus1 described above.
• In the film-forming method, of the gas introduced in thereaction furnace3, the gas to be introduced into thereaction furnace3 and the gas exhausted from thereaction furnace3, the components of the gas in thereaction furnace3 or the components of at least two gases and the concentration of each component of the gas are first measured, at two or more different positions in thereaction furnace3,gas inlet pipe5 andgas outlet pipe6. Then, the components of theprocess gas4, the concentration of each component, and the atmosphere in thereaction furnace3 are adjusted on the basis of the values measured, so that an appropriate film-forming process may be carried out on thewafer2 held in thereaction furnace3.
• The film-forming method according to this embodiment is carried out by the use of the film-formingapparatus1 described above. The operation and advantages of the method are therefore similar to those of the film-formingapparatus1. That is, the film-forming method according to the present embodiment can change the process parameters (control parameters) to appropriate values, if necessary. Thus, the film-forming process can be appropriately effectuated, irrespective of its type, in accordance with the conditions in which a thin film is being formed on thewafer2. The method can therefore manufacture a semiconductor device having thin films of desired quality.
• A cleaning method for use in an apparatus for manufacturing a semiconductor device, according to the present embodiment, will be described. The cleaning method according to the first embodiment is performed by the use of the film-formingapparatus1 that has been described.
• Film-forming apparatuses perform film-forming processes such as oxidation and CVD. Generally, a cleaning process must be carried out in, for example, a CVD apparatus, to remove residues (attached objects) deposited on the inner walls of thereaction furnace3 after the film-forming process is completed. The film-formingapparatus1 can be effectively applied to this cleaning process.
• Generally, the optimal conditions in a cleaning process vary, depending on the kind of the attached object to be removed. One film-forming apparatus may perform film-forming processes of various types. In this case, the attached object to be removed may vary, depending on the time (process stage) when the cleaning should be carried out. As indicated above, the film-formingapparatus1 can detect, in real time, the gas components in thereaction furnace3 and the concentration of each gas component. Therefore, it is very easy for theapparatus1 to determine the kind of the object to be removed at the time of performing the cleaning process. Further, optimal cleaning conditions can be set in accordance with the kind of the object to be removed, so that the interior ofreaction furnace3 and the like can be cleaned with ease.
• Various materials of films may deposit, forming an attached object that is a multi-layer structure composed of layers of different materials. If this is the case, the cleaning conditions must be changed in accordance with the kind of the object that should be removed. Nonetheless, the optimal cleaning conditions can be easily set in accordance with the kind of the object to be removed, thereby to clean the interior of thereaction furnace3 or the like with ease. This is because the film-formingapparatus1 monitors, in real time, changes in the gas components in thereaction furnace3 and changes in the concentration of each gas component.
• That is, the film-formingapparatus1 can easily detect the kind and components of the residue deposited in the furnace. It can then select an optimal cleaning sequence in accordance with the kind and components of the residue.
• As has been explained, in the cleaning method for use in an apparatus for manufacturing a semiconductor device, according to the first embodiment of this invention, thewafer2 is removed from inside thereaction furnace3 after the film-formingapparatus1 has performed a film-forming process on thewafer2. Then, a cleaning gas that can remove the residue from inside thegas inlet pipe5,reaction furnace3 andgas outlet pipe6 is prepared on the basis of the values measured by the first mass analyzer15 and second mass analyzer19. Additionally, the atmosphere in thereaction furnace3 is so set to increase the fluidity of the gas and residue that remains in thereaction furnace3. Thereafter, the cleaning gas is made to flow from thegas inlet pipe5 to thegas outlet pipe6 through thereaction furnace3 until the residue is taken out of thegas inlet pipe5,reaction furnace3 andgas outlet pipe6.
• One film-formingapparatus1 may be used to repeat a film-forming process several times on thewafer2. In this case, the components of the cleaning gas and the concentration of each gas component are adjusted every time the film-forming process ends, in accordance with the process sequence. They are adjusted on the basis of the values measured by the first and second mass analyzers15 and19 and/or the gas components at the predetermined position in thereaction furnace3 and the concentration of each gas component determined from the values measured by the mass analyzers15 and19. The cleaning gas is then made to flow while the atmosphere in thereaction furnace3 is being adjusted on the basis of the process parameters that have been updated as described above.
• In the cleaning method for use in a method of manufacturing a semiconductor device, according to the first embodiment, the unnecessary components that may interfere with the film-forming process are removed from thegas inlet pipe5 andreaction furnace3 after the film-forming process has been carried out on thewafer2. Hence, the next film-forming process can be performed in appropriate conditions, and the interior of thegas inlet pipe5 and the interior of thereaction furnace3 can remain clean. The film-forming processes can therefore be performed on thewafer2 in appropriate conditions, regardless of their types. This serves to manufacture desirable semiconductor devices easily.
SECOND EMBODIMENT
• An apparatus for, and method of, manufacturing a semiconductor device and a cleaning method for use in the apparatus for manufacturing a semiconductor device, both according to the second embodiment of this invention, will now be described with reference toFIG. 3. Any component identical to that of the first embodiment are designated at the same reference numeral and will not be described. The apparatuses for manufacturing a semiconductor device and the cleaning methods for use in a method of manufacturing a semiconductor device, according to the third to fifth embodiments of the invention, will be described in the same manner.
• As may be seen fromFIG. 3, the film-formingapparatus31, which is an apparatus for manufacturing a semiconductor device, according to the present embodiment, is a wet-oxidation type that uses aprocess gas32 composed of hydrogen and oxygen. Theprocess gas32 composed of hydrogen and oxygen is applied into thecombustion device34 coupled to thegas inlet pipe5, before introduced via thegas inlet pipe5 into thereaction furnace3 by acontroller33. Thecontroller33 comprises first and second mass-flow controllers33aand33bthat are provided for hydrogen and oxygen, respectively. Theprocess gas32 composed of hydrogen and oxygen is combusted in thecombustion device34 and then introduced into thereaction furnace3. The second embodiment described above can attain the same advantages as the first embodiment.
THIRD EMBODIMENT
• An apparatus for, and method of, manufacturing a semiconductor device, and a cleaning method for use in the apparatus of manufacturing a semiconductor device, both according to the third embodiment of the present invention, will now be described with reference toFIG. 4.
• AsFIG. 4 shows, a film-formingapparatus41 according to this embodiment, i.e., an apparatus for manufacturing a semiconductor device, has the first mass analyzer42. The analyzer42 is provided in areaction furnace3 and positioned on the upstream side of awafer2 and near thegas inlet port13. Theapparatus41 has the second mass analyzer43. The analyzer43 is provided in thereaction furnace3, too, and located on the downstream side of thewafer2 and near thegas outlet port16.
• The third embodiment described above can achieve the same advantages as the first embodiment. In the film-formingapparatus41 according to the present embodiment, the first mass analyzer42 is provided in thereaction furnace3 and fixed on the upstream of thewafer2 and near thegas inlet port13. And the second mass analyzer43 is provided in thereaction furnace3 and secured on the downstream side of thewafer2 and near thegas outlet port16. Having this positional relation, the analyzers42 and43 monitor the components of the gas in thereaction furnace3 and the concentration of each gas component. Thus, the components the gas has at a predetermined position in thereaction furnace3 and the concentration of each gas component can be obtained with higher precision than otherwise. Thus, the film-forming process can be performed on thewafer2 in more appropriate conditions, irrespective of the type of the process. This makes it easy to provide a semiconductor device of higher quality.
FOURTH EMBODIMENT
• An apparatus for, and method of, manufacturing a semiconductor device, and a cleaning method for use in the apparatus for manufacturing a semiconductor device, both according to the fourth embodiment of the present invention, will now be described with reference toFIG. 5.
• As may be seen fromFIG. 5, a film-formingapparatus51 according to this embodiment, i.e., an apparatus for manufacturing a semiconductor device, is a film-forming apparatus of batch type. Thus, a plurality ofwafers2, for example six wafers, are held in thereaction furnace3 at the same time. In the film-formingapparatus51, thegas inlet pipe5 extends in thereaction furnace3, almost reaching the ceiling thereof. Thegas inlet port13 of thegas inlet pipe5 therefore lies near the uppermost one of the sixwafers2. The first mass analyzer52 is provided in thereaction furnace3 and located on the upstream side of theuppermost wafer2 and near thegas inlet port13. The second mass analyzer53 is provided in thereaction furnace3, too, and positioned on the downstream side of thelowermost wafer2 and near thegas outlet port16.
• The fourth embodiment described above can achieve the same advantages as the first embodiment. In the film-formingapparatus51 according to this embodiment, the first mass analyzer52 and the second mass analyzer53 are secured at the positions specified above. The analyzers52 and53 can therefore measure the components the gas has at a predetermined position in thereaction furnace3 and the concentration of each gas component, with higher precision, though the film-formingapparatus51 is a batch-type one. Hence, the film-forming process can be performed on thewafer2 in more appropriate conditions, regardless of the type of the process. This makes it easy to provide a semiconductor device of higher quality. Moreover, theapparatus51 can manufacture a high-quality semiconductor device with high efficiency, since it is a batch-type apparatus.
FIFTH EMBODIMENT
• An apparatus for, and method for, manufacturing a semiconductor device, and a cleaning method for use in the apparatus for manufacturing a semiconductor device, both according to the fifth embodiment of the invention, will now be described with reference toFIGS. 6 and 7.
• AsFIG. 6 depicts, the film-formingapparatus61 according to this embodiment, which is an apparatus for manufacturing a semiconductor device, comprises four mass analyzers62,63,64 and65. The analyzers62 to65 are provided in thereaction furnace3 and arranged along the gas flow. In thereaction furnace3, the first mass analyzer62 is located on the upstream side of thewafer2 and near thegas inlet port13. In thereaction furnace3, the second mass analyzer63 is positioned on the upstream side of thewafer2 and immediately adjacent to thewafer2. In thereaction furnace3, the third mass analyzer64 lies on the downstream side of thewafer2 and quite close to thewafer2. In thereaction furnace3, the fourth mass analyzer43 is located on the downstream side of thewafer2 and near thegas outlet port16.
• The fifth embodiment described above can attain the same advantages as the first embodiment. In the film-formingapparatus61 according to the fifth embodiment, the four mass analyzers62,63,64 and65 are secured at the positions specified above. They can therefore detect, with an extremely high precision, the components the gas has at predetermined positions in thereactor furnace3 and the concentration of each gas component, as is indicated by the broken line shown inFIG. 7. Hence, the film-forming process can be performed on thewafer2 in very appropriate conditions, regardless of the type of the process. This makes it easy to provide a semiconductor device of very high quality.
• Any apparatus for, and any method for, manufacturing a semiconductor device, and any cleaning method for use in the apparatus for manufacturing a semiconductor device, according to the present invention, are not limited to the first to fifth embodiments described above. The embodiments may be modified in structure and in some of the steps, in various ways. Alternatively, various settings may be combined and utilized.
• For example, each embodiment described above uses mass analyzers, each comprising a component-measuring device and a concentration-measuring device, as means for monitoring the components of the process gas in thegas inlet pipe5,reaction furnace3 andgas outlet pipe6 and the concentration of each component of the process gas. The mass analyzers are not limited to this type, nonetheless. Mass analyzers of any other type may be employed instead, provided that they can accurately analyze the gas components and the concentration of each gas component.
• In each embodiment described above, the process-parameter database unit20, process-parameter database unit20, concentration-calculatingunit22, calculation-model database unit23 and process-sequence database unit24 are incorporated in thecontroller9 and formed integral with one another. Nevertheless, the process-parameter database unit20, process-parameter database unit20, concentration-calculatingunit22, calculation-model database unit23 and process-sequence database unit24 may be provided in an apparatus for manufacturing a semiconductor device, according to this invention, each arranged outside thecontroller9 and operating independent of any other device.
• Furthermore, apparatus for, and any method for, manufacturing a semiconductor device, and any cleaning method for use in the apparatus for manufacturing a semiconductor device, according to the present invention, can be applied to various hot processes, such as thermal oxidation, thermal nitriding, annealing, RTP, and CVD and the like.
• Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader embodiments is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.

Claims (9)

1. An apparatus for manufacturing a semiconductor device, comprising: a process chamber which holds a substrate to be subjected to a prescribed process; a gas inlet pipe which is connected and communicates with an interior of the process chamber and which introduces a process gas for use in the process, into the process chamber; a gas outlet pipe which is connected and communicates with the interior of the process chamber and which discharges the gas from the process chamber to outside the process chamber; component-measuring devices which are provided at two or more positions selected from the group comprising of a position in the process chamber, a position in the gas inlet pipe and a position in the gas outlet pipe, and which measure components of the gas in the process chamber or at least two different gases selected from the group comprising of gas in the process chamber, gas to be introduced into the process chamber and gas discharged from the process chamber; concentration-measuring devices which are provided at two or more positions selected from the group comprising of a position in the process chamber, a position in the gas inlet pipe and a position in the gas outlet pipe, and which measure concentration of each component of the gas in the process chamber, or the concentration of each component of at least two different gases selected from the group comprising of the gas in the process chamber, the gas to be introduced into the process chamber and the gas discharged from the process chamber; and a control device which adjusts the components of the process gas, the concentration of each component of the process gas and an atmosphere in the process chamber, on the basis of values measured by the component-measuring device and concentration-measuring device, such that an appropriate process is performed on the substrate.

2. An apparatus according toclaim 1, wherein at least one component-measuring device and at least one concentration-measuring device are provided on either side of the substrate held in the process chamber, two sides of the substrate being at upstream and downstream of the gas flowing from the gas inlet pipe to the gas outlet pipe through the process chamber and of the gas flowing in the process chamber.

3. An apparatus according toclaim 1, further comprising: a component-calculating unit which calculates the components the gas has at a predetermined position in the process chamber, on the basis of values the component-measuring devices obtain and at almost the same time the component-measuring devices obtain the values; and a concentration-calculating unit which calculates the concentration each gas component has at the predetermined position in the process chamber, on the basis of the values the concentration-measuring devices obtain and at almost the same time the concentration-measuring devices obtain the values.

4. An apparatus according toclaim 2, wherein at least one component-measuring device and at least one concentration-measuring device are provided at the gas inlet pipe, and at least one component-measuring device and at least one concentration-measuring device are provided at the gas outlet pipe.

5. An apparatus according toclaim 2, wherein at least one component-measuring device and at least one concentration-measuring device are provided in the process chamber and on the upstream side of the substrate, and at least one component-measuring device and at least one concentration-measuring device are provided in the process chamber and on the downstream side of the substrate.

6. An apparatus according toclaim 2, wherein a plurality of substrates to be processed are held in the process chamber, at least one component-measuring device is provided in the process chamber and at an upstream side of the substrate which is held upstream of any other substrate, and at least one component-measuring device is provided in the process chamber and at a downstream side of the substrate which is held downstream of any other substrate.

7. An apparatus according toclaim 2, wherein at least one component-measuring device and at least one concentration-measuring device are provided near a gas inlet port which is open and provided at that end of the gas inlet pipe which communicates with the interior of the process chamber, and at least one component-measuring device and at least one concentration-measuring device are provided near a gas outlet port which is open and provided at that end of the gas outlet pipe which communicates with the interior of the process chamber.

8. The apparatus according toclaim 3, wherein the control device updates a plurality of process parameters for setting the components of the process gas, the concentration of each component thereof, the atmosphere in the process chamber and a progress of the process, each at a prescribed condition, on the basis of the values calculated by the component-calculating unit and concentration-calculating unit; and the control device adjusts the components of the process gas, the concentration of each component thereof, the atmosphere in the process chamber and the progress of the process, on the basis of the process parameters thus updated, in order to perform the process on the substrate in appropriate conditions.

9. An apparatus according toclaim 3, wherein the control device has a plurality of process sequences, each comprising of prescribed steps of the process to be performed on the substrate; and the control device selects one of the process sequences, which meets the condition of the next process step to be carried out immediately after the component-calculating unit and the concentration-calculating unit perform calculations, on the basis of the values calculated by the component-calculating unit and concentration-calculating unit, in order to process the substrate in appropriate conditions.

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