The method and apparatus realizing impedance matching in chamber is processed at multiple frequency plasmaTechnical field
Relate to semiconductor technology and manufacture field, particularly relate to multiple frequency plasma and process the impedance matching in chamber.
Background technology
In the manufacture process of semiconductor equipment, for instance in the processing procedures such as etching, deposition, oxidation, sputtering, it will usually utilize plasma that substrate (semiconductor wafer, glass substrate etc.) is processed. Typically, for plasma treatment module, as the mode generating plasma, can be generally divided into and utilize corona (glow) electric discharge or high-frequency discharge, and utilize the modes such as microwave.
In the plasma treatment module of high-frequency discharge mode, the process chamber of plasma treatment module generally configures upper electrode and lower electrode, it is preferable that the two electrode runs parallel is arranged. And, the generally processed substrate of mounting on lower electrode, the high frequency power generated by plasma via integrator puts on upper electrode or lower electrode. Make electronics accelerate by the high-frequency electric field generated by this high frequency power, because of the impact ionization of electronics and place's process gases, radio frequency plasma occurs.
In existing technique, when usual plasma process chamber bottom electrode only connects a RF source power source, the impedance of chamber interior is constant, and therefore impedance matching is more convenient. But, present plasma process chamber has often coupled two radio frequency power sources at bottom electrode place, one of them is RF source power source, for increasing the plasma bombarding energy to processing chamber surfaces, another is bias power source (and being impulse modulation output), is used for producing plasma. The now impedance of chamber interior is change, and this change is relevant to the impulse modulation in this bias power source output, and therefore the method for the impedance matching of prior art is infeasible. That is, when a radio frequency power source is in pulse condition wherein, another being exported continuously or mates usually by the algorithm carried with another radio frequency power source of the radio frequency power source lock-out pulse modulation output of impulse modulation output, whether coupling completes according to the whether minimum judgement of reflection power. In pulse process, because there are 2 states, and traditional coupling cannot judge the pulse condition of radio frequency power source that pulse exports, so the reflection power read a simply meansigma methods in both pulse condition on an off situation, specifically, as it is shown in figure 1, be subject to the impact of the radio frequency power source of impulse modulation output due to reflection power, reflection power reads inaccurate, naturally just cannot accomplish the impedance matching of radio frequency power source.
Summary of the invention
For technological deficiency of the prior art, the present invention provides a kind of method processing at multiple frequency plasma and realizing automatic impedance matching in chamber, wherein, described plasma process chamber includes a bottom electrode, bottom electrode is connected to the first radio frequency power source and the second radio frequency power source, described first radio frequency power source is impulse modulation output, and wherein, described method comprises the steps: to obtain the first real-time power value and the second real-time power value of the power output of described first radio frequency power source; Control to sample when reflection power reaches each described first real-time power value and the second real-time power value at described first radio frequency power source according to described first real-time power value and the second real-time power value; Impedance in chamber is mated by the sampling according to described reflection power.
Preferably, the rising edge of described first real-time power value and the second real-time power value respectively power output waveform of described first radio frequency power source and trailing edge.
Preferably, the impedance in described plasma process chamber is carried out coupling and includes by the described sampling according to described reflection power: at described first radio frequency power source, reflection power is reached each sampling of each described first real-time power value gained and averages to obtain the first sampling of described reflection power; To reflection power described first radio frequency power source reach each described second real-time power value gained each sampling average to obtain described reflection power second sampling; The impedance that the first sampling and second according to described reflection power samples in plasma process chamber is mated.
Preferably, the way of output of described second radio frequency power source includes the one in the following way of output: export continuously; Or the impulse modulation output Tong Bu with described first radio frequency power source.
Preferably, described first radio frequency power source includes one or more radio frequency power source for producing RF bias power, and its frequency range is one or more in 360 to 440KHz, 1.8 to 2.3MHz and 12.8 to 14.3MHz; Described second radio frequency power source is used for producing RF source power, and its frequency is the one in 27MHz, 40MHz, 60MHz, 100MHz and 120MHz.
Preferably, the power bracket of described first radio frequency power source is 100 watts to 10000 watts, and the power bracket of described second radio frequency power source is 100 watts to 3000 watts.
Also provide for a kind of impedance-matching device processing chamber for multiple frequency plasma according to another aspect of the invention, wherein, described plasma process chamber includes a bottom electrode, bottom electrode is connected to the first radio frequency power source and the second radio frequency power source, described first radio frequency power source is modulated output by an integrated or external pulse signal source, described first radio frequency power source and described second radio frequency power source are connected to described bottom electrode respectively through match circuit, described impedance-matching device includes: acquisition module, for obtaining the first real-time power value and the second real-time power value of the power output of described first radio frequency power source, sampling module, for controlling to sample when reflection power reaches each described first real-time power value and the second real-time power value at described first radio frequency power source according to described first real-time power value and the second real-time power value, impedance matching module, mates the impedance in chamber for the sampling according to described reflection power.
Preferably, the rising edge of described first real-time power value and the second real-time power value respectively power output waveform of described first radio frequency power source and trailing edge.
Preferably, described impedance matching module includes: the first averaging module, for reflection power described first radio frequency power source reach each described first real-time power value gained each sampling average to obtain described reflection power first sampling; Second averaging module, for reflection power described first radio frequency power source reach each described second real-time power value gained each sampling average to obtain described reflection power second sampling; First impedance matching module, the impedance come in plasma process chamber for the first sampling according to described reflection power and the second sampling is mated.
Preferably, the way of output of described second radio frequency power source includes the one in the following way of output: export continuously; Or the impulse modulation output Tong Bu with described first radio frequency power source.
Preferably, described impedance-matching device is included in described second radio frequency power source.
Preferably, described impedance-matching device is included in the match circuit being connected with described second radio frequency power source.
Preferably, described first radio frequency power source includes one or more radio frequency power source for producing RF bias power, and its frequency range is one or more in 360 to 440KHz, 1.8 to 2.3MHz and 12.8 to 14.3MHz; Described second radio frequency power source is used for producing RF source power, and its frequency is the one in 27MHz, 40MHz, 60MHz, 100MHz and 120MHz.
Preferably, described first radio frequency power source range for 100 watts to 10000 watts, described second radio frequency power source range for 100 watts to 3000 watts.
The present invention controls reflection power is sampled when RF bias power reaches each above-mentioned real-time power value by the real-time power value different when pulse signal is on an off according to the RF bias power through a pulse signal source modulation output, and mate according to the impedance in the reflection power plasma process chamber of sampling, realize the accurate reading of reflection power, increase the speed and the accuracy that process radio frequency source automatic impedance matching in chamber at multiple frequency plasma further.
Accompanying drawing explanation
By reading detailed description non-limiting example made with reference to the following drawings, the other features, objects and advantages of the present invention will become more apparent upon:
Fig. 1 illustrates prior art, the schematic diagram of RF bias power, RF source power and corresponding reflection power;
Fig. 2 illustrates the flow chart processing the method realizing automatic impedance matching in chamber at a multiple frequency plasma according to the present invention;
Fig. 3 illustrates the schematic diagram of the waveform of the output of the power according to the first radio-frequency power according to the present invention and reflection power; And
Fig. 4 illustrates that the multiple frequency plasma according to the present invention processes the structural representation of chamber.
Detailed description of the invention
The invention provides a kind of method processing at multiple frequency plasma and realizing automatic impedance matching in chamber. Two radio frequency power sources have often been coupled at bottom electrode place due to plasma process chamber, the impedance of chamber interior is change, and this change is relevant to the impulse modulation in this bias power source output, therefore the acquisition of real-time power under different conditions when method provided by the present invention is by exporting the pulse of bias power source, according to the control to the sampling of reflection power of its different conditions the reflection power according to sampling, the impedance in chamber is mated, realize the realization of impedance matching under chamber internal impedance variable condition.
With reference to Fig. 2, first in step S101, obtain the first real-time power value and the second real-time power value of the power output of described first radio frequency power source. In one embodiment, obtain described first radio frequency power source power output oscillogram in rising edge and the real-time power value (will be shown in further detail at Fig. 3) of trailing edge. In step S102, control to sample when reflection power reaches each described first real-time power value and the second real-time power value at described first radio frequency power source according to described first real-time power value and the second real-time power value. Real-time power value according to this rising edge and trailing edge controls reflection power and samples when described first radio frequency power source reaches the real-time power value of each rising edge and trailing edge. In step S103, mate according to the impedance that the sampling of described reflection power comes in plasma process chamber. Specifically, plasma processes the impedance matching method of the prior art of chamber.
Skilled artisan understands that, first radio frequency power source includes the radio frequency power source for producing one or more RF bias power, for controlling ion energy and Energy distribution thereof, its frequency range is one or more in 360 to 440KHz, 1.8 to 2.3MHz and 12.8 to 14.3MHz. Second radio frequency power source is used for producing RF source power, is used for controlling plasma ions and dissociates or plasma density, and its frequency is the one in 27MHz, 40MHz, 60MHz, 100MHz and 120MHz. Wherein, the first radio frequency power source exports different bias powers from RF source power cooperation to meet different needs by impulse modulation. Such as, during higher bombarding energy, the such as application of front end etching, the bias power of available 1.8 to 2.3MHz, and for need milder bombardment time, the such as application of rear end etching, the bias power of available 12.8 to 14.3MHz.
More specifically, the second radio frequency power source is preferably, it it is a radio frequency power source exported continuously. Obtain the first radio frequency power source oscillogram real-time power value at rising edge and trailing edge, then when the first radio frequency power source output arrives the real-time power value of rising edge, reflection power is sampled, and the impedance in chamber is mated by the reflection power according to sampling. Reflection power can be the reflection power of the second radio frequency power source. Same, when the first radio frequency power source output arrives the real-time power value of trailing edge, reflection power is sampled. In one embodiment, to reflection power described first radio frequency power source reach each described first real-time power value (namely the real-time power value of the first radio frequency power source output rising edge) gained each sampling average to obtain described reflection power first sampling. To reflection power described first radio frequency power source reach each described second real-time power value (namely the real-time power value of the first radio frequency power source output trailing edge) gained each sampling average to obtain described reflection power second sampling. The impedance come in plasma process chamber finally according to the first sampling and second sampling of described reflection power is mated. In the another change case of the present embodiment, the second radio frequency power source is the radio frequency power source of the impulse modulation Tong Bu with a described first radio frequency power source output. The embodiment that its embodiment and the second radio frequency power source are a radio frequency power source exported continuously is similar, specifically, does not repeat them here. Those skilled in the art in conjunction with the more embodiment of existing techniques in realizing, can not repeat them here.
Fig. 3 illustrates the schematic diagram of the waveform of the output of the power according to the first radio-frequency power according to the present invention and reflection power. Specifically, Fig. 3 being the oscillogram of the power output of the first radio-frequency power, Fig. 3 is the oscillogram of reflection power sampling. When the first radio-frequency power source power output waveform figure rising edge, namely when the first radio frequency power source pulse signal is for opening (on), obtain the first real-time power. When the first radio-frequency power source power output waveform figure trailing edge, namely when the first radio frequency power source pulse signal is for opening (off), obtain the second real-time power. Trigger when arriving the first real-time power or the second real-time power when the first radio frequency power source and reflection power is sampled. Specifically, the reflection power oscillogram of the second radio frequency power source read according to above-mentioned steps is not as it is shown on figure 3, repeat them here.
Fig. 4 illustrates that multiple frequency plasma processes the structural representation of chamber according to the first embodiment of the present invention. Specifically, this graph show that a multiple frequency plasma that can realize RF source power automatic impedance matching processes chamber 1, described plasma process chamber 1 includes a bottom electrode 13. Bottom electrode 13 is connected to the first radio frequency power source 2 and the second radio frequency power source 4. In an embodiment of the present invention, the external pulse signal source 6 of described first radio frequency power source 2 is modulated and exports to the first match circuit. In an alternative embodiment of the invention, described first radio frequency power source 2 can be modulated and export to the first match circuit by an integrated pulse signal source 6. Described first radio frequency power source 2 and described second radio frequency power source 4 are connected to described bottom electrode 13 respectively through the first match circuit 3 and the second match circuit 5. In an embodiment of the present invention, described second match circuit 5 can also include impedance-matching device, realizes automatic impedance matching for processing in chamber at multiple frequency plasma. Described impedance-matching device draws together acquisition module, sampling module and impedance matching module. In another embodiment of the present invention, described impedance-matching device can also include in the second radio frequency power source 4.
Specifically, acquisition module, for obtaining the first real-time power value and the second real-time power value of the power output of described first radio frequency power source 2. In one embodiment, acquisition module obtains the real-time power value of the rising edge in the oscillogram of the power output of described first radio frequency power source 2 and trailing edge. Sampling module, for controlling to sample when reflection power reaches each described first real-time power value and the second real-time power value at described first radio frequency power source according to described first real-time power value and the second real-time power value. In one embodiment, sampling module controls reflection power for this rising edge obtained according to acquisition module and the real-time power value of trailing edge and samples when described first radio frequency power source reaches the real-time power value of each rising edge and trailing edge. Impedance matching module, mates for the impedance come in plasma process chamber according to the sampling of described reflection power. Specifically, plasma processes the impedance matching method of the prior art of chamber.
In the present embodiment, first radio frequency power source 2 preferably includes two radio frequency power sources for producing two RF bias power, and the first radio frequency power source 2 provides switchable radio-frequency bias frequency by pulse signal source 6 and its corresponding first match circuit 3 to processing chamber 1. Described radio-frequency bias frequency is generally 1.8 to 2.3MHz and 12.8 to 14.3MHz. Second radio frequency power source 4 is used for producing RF source power, is used for controlling plasma density, and namely plasma ion dissociates. Preferably, the second radio frequency power source 4 is the radio frequency power source of a continuous output, and generally its frequency is the one in 27MHz, 40MHz, 60MHz, 100MHz and 120MHz. In the present embodiment, the input power range of the second radio frequency power source is 100 watts to 3000 watts. In a change case of the present embodiment, second radio frequency power source 4 is the radio frequency power source of the impulse modulation Tong Bu with described first radio frequency power source 2 output, adaptably, the pulse signal source providing pulse signal with described first radio frequency power source 2 provides pulse signal to the second radio frequency power source 4 simultaneously, the pulse frequency of the second radio frequency power source 4 is consistent with the pulse frequency of the first radio frequency power source 2, its input power range for 100 watts to 3000 watts. In the another change case of the present embodiment, described first radio frequency power source 2 only includes a radio frequency power source for producing RF bias power, and its embodiment is similar with above-described embodiment.
Above specific embodiments of the invention are described. It is to be appreciated that the invention is not limited in above-mentioned particular implementation, those skilled in the art can make various deformation or amendment within the scope of the claims, and this has no effect on the flesh and blood of the present invention.