Disclosure of Invention
In view of the above, the present application provides a semiconductor device and a surface coating method thereof, which comprises the following steps:
a surface coating method of a semiconductor device, comprising:
providing an equipment body to be coated;
forming a first protective layer on the surface of the equipment body; the first protective layer at least comprises a first sub-protective layer formed based on an atomic layer deposition process.
Preferably, in the above surface coating method, the method for forming the first sub-protective layer includes:
and sequentially forming an atomic layer film on the surface of the equipment body by adopting an atomic layer deposition process, and taking the atomic layer film as the first sub-protective layer.
Preferably, in the above surface coating method, the method for forming the first sub-protective layer includes:
Forming a first atomic layer film based on saturated chemisorption and reaction of a first precursor with a surface of the device body;
forming another atomic layer film based on saturated chemisorption and reaction of the second precursor and the surface of the previous atomic layer film;
Wherein the precursor for forming the previous atomic layer film is purged and discharged before forming the next atomic layer film.
Preferably, in the surface coating method, before forming the first protective layer, the method further includes:
and preprocessing the surface of the equipment body to improve the adhesion stability of the first sub-protective layer on the surface of the equipment body.
Preferably, in the above surface coating method, the method for pretreating the surface of the device body includes:
and carrying out modification treatment on the surface of the equipment body by adopting a first plasma immersion process, so that a gradual transition layer with gradually changed doping components is formed in the surface of the equipment body.
Preferably, in the surface coating method, a first plasma immersion process is adopted to modify the surface of the device body, including:
ion implantation of a first depth is performed in the surface of the equipment body under a first pulse bias;
Performing ion implantation of a second depth into the surface of the device body and/or performing surface alloying of the device body under a second pulse bias;
Wherein the second depth is less than the first depth.
Preferably, in the surface coating method, the method for forming the first protective layer further includes:
and forming a second sub-protective layer on the surface of the first sub-protective layer by adopting a second plasma immersion process.
Preferably, in the above surface coating method, a second sub-protective layer is formed on the surface of the first sub-protective layer by using a second plasma immersion process, including:
and under the negative bias less than 15kV, performing omnibearing film plating on the surface of the equipment body provided with the first sub-protection layer to form the second sub-protection layer.
Preferably, in the surface coating method, the method further includes:
Forming a second protective layer on the surface of the first protective layer;
the thickness of the second protective layer is larger than that of the first protective layer.
Preferably, in the surface coating method, the method for forming the second protective layer includes:
and forming the second protective layer by adopting a plasma enhanced physical vapor deposition process.
The present application also provides a semiconductor device including:
an equipment body;
And the first protection layer at least comprises a first sub-protection layer formed based on an atomic layer deposition process.
Preferably, in the above semiconductor device, the first sub-protective layer includes a plurality of atomic layer thin films stacked in sequence.
Preferably, in the above semiconductor device, the surface of the device body is subjected to modification treatment to improve adhesion stability of the first sub-protective layer on the surface of the device body.
Preferably, in the above semiconductor device, the first protective layer further includes: a second sub-protective layer on the surface of the first sub-protective layer;
The second sub-protective layer is a film layer formed by a plasma immersion process.
Preferably, in the above semiconductor device, the first protective layer includes a ceramic thin film.
Preferably, in the above semiconductor device, further comprising:
And a second protective layer on the surface of the first protective layer.
Preferably, in the above semiconductor device, the second protective layer is a plasma enhanced physical vapor deposition film.
Preferably, in the above semiconductor device, the thickness of the first protective layer is less than 25 μm, and the thickness of the second protective layer is greater than 10 μm.
Preferably, in the above semiconductor device, the second protective layer is a ceramic film.
Preferably, in the above semiconductor device, the thickness of the second protective layer is greater than the thickness of the first protective layer.
As can be seen from the above description, in the surface coating method and the semiconductor device provided by the technical scheme of the present application, the first protection layer is formed on the surface of the device body, and the first protection layer at least includes the first sub-protection layer formed based on the atomic layer deposition process, so that the surface of the device body can be covered with an omnibearing film, so as to improve corrosion resistance.
Detailed Description
Embodiments of the present application will now be described more fully hereinafter with reference to the accompanying drawings, in which it is shown, however, in which some, but not all embodiments of the application are shown. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.
Currently, in a large number of semiconductor thin film deposition apparatuses such as Physical Vapor Deposition (PVD) and Chemical Vapor Deposition (CVD) systems, a large number of flat-plate type gas distribution plate workpieces based on 6061T aluminum alloy, such as an aluminum alloy Showerhead (SH), are still used in the reaction chamber. Aluminum alloy components without surface protection are not suitable for direct contact with reactive gases and plasmas to prevent corrosion of the components that can result in metal and particle contamination. The instability of the surface tissues and components of the aluminum alloy workpieces can react with chemical reaction gases (such as O2、SiH4、TMA、TEOS、NH3、SiCl4、N2O、C2F6、SF6、SiC4、HBr、NF3、CF4、CHF3、CH2F2、Cl2、CCl4、BCl3、SiF4 and the like) and plasmas formed in the process of depositing semiconductor films such as CVD, PVD and the like, so that unnecessary chemical reaction consumption of chemical components forming film deposition on the surface of a cavity is caused, the film deposition rate is uneven and unstable, particle and trace element pollution is generated, and the process stability of film deposition is seriously affected. Therefore, the structural stability of the component structure and the surface material of the reaction chamber of the semiconductor device is improved through the surface modification of the omnibearing material, such as omnibearing coating protection, and the particle pollution (particle size and number) in the film deposition and etching process is reduced, so that the method is an important way for ensuring the stable performance of the high-quality chip processing process and reducing the production cost.
In a semiconductor chip film deposition and plasma etching machine system, surface protection treatment is generally performed on the inner wall of a reaction cavity and key components by adopting anodic oxidation, plasma spraying (PLASMA SPRAY, abbreviated as PS) yttrium oxide and the like so as to enhance the chemical corrosion resistance and the plasma etching resistance of the surface of a cavity component. Although anodic oxidation can realize the omnibearing oxidation protection of the surface of an aluminum alloy workpiece, anodic oxidation structure has poor stability, can not stably work in an environment of more than 100 ℃, and cannot be used for film deposition processes (such as PVD, PECVD and the like) with higher temperature. In addition, even the member having the anodic protection layer is not recommended to be directly contacted with the reaction gas or plasma because the anodic oxide tissue contains cracks, and contamination of particles and trace elements such as Al is generated in the plasma environment. And PS coating (such as PS Y2O3) has loose structure and rough surface, and pollution particles are easy to generate in the plasma etching process, so that the high-precision chip etching process (such as below 15 nm) is difficult to stably carry out.
In recent years, the deposition of dense thick coatings by using a plasma enhanced physical vapor deposition (PLASMA ENHANCED PHYSICAL vapor deposition, or PEPVD) process has been gradually widened, so that the surface structure stability and the service life of key components such as a gas shower head and a ceramic window can be effectively improved, but the linear film deposition characteristic of PEPVD makes the process unable to effectively coat and protect the pores of certain key components such as the gas shower head and the inside of a gas pipeline, and unable to deposit a protective film resistant to plasma etching on the inner surfaces of the pores, so that the inner surfaces of the pores cannot be prevented from being polluted by metals and particles generated by the corrosion of reaction gases or plasma etching in the plasma etching process.
The same problems as described above are found in most cylindrical workpieces and gas pipe workpieces used in semiconductor devices, which are made of aluminum alloy or stainless steel. Since these workpieces are typically used to deliver plasmas or various reactive gases, their inner surfaces are inevitably subject to erosion by the plasmas and reactive gases. Conventional coating processes (such as PS, PECVD, PVD, etc.) do not provide good film protection for the inner surfaces of these workpieces, but only anodic oxidation. As mentioned above, this can lead to many processes being subject to metal and particle contamination. In addition, for stainless steel gas pipes with smaller diameters (such as less than 1 cm), under the condition of being corroded by reaction gases (such as Cl2、NF3, HBr and the like), particularly when the stainless steel gas pipes are corroded at the temperature of 150 ℃ and above, the surface tissues of the stainless steel gas pipes are very easy to generate particles and microelements due to the fact that the inner surfaces of the stainless steel gas pipes cannot be effectively protected by surface coatings, and then pollution of the raw particles and microelements is introduced in the chip processing process. To solve this problem, generally, only a hafnium alloy, which is expensive, or a heat-resistant alloy having high Cr and high Ni content can be used.
In view of this, the embodiment of the application provides a semiconductor device and a surface coating method thereof, which can be used for thin film deposition (such as PVD, CVD, etc.) devices and important components of a plasma etcher (PLASMA ETCHER), such as plate-type key workpieces (such as SH, etc.) and hollow cylinder-type workpieces (such as cylinders and air pipes, etc.). The surface coating method is a material surface omnibearing surface coating protection method capable of effectively enhancing working stability, and can effectively prepare a protection layer on the inner surface of a cylindrical workpiece even if the diameter and depth of a round hole reach 1:200 so as to prolong the service life of the workpiece. The technical scheme of the application can effectively enhance the process stability of semiconductor equipment (such as equipment for film deposition, plasma etching and the like), and obviously reduce the risks of particle pollution and trace element pollution in the process of different semiconductor equipment, thereby improving the process stability of integrated circuit chip production, improving the production efficiency and reducing the production cost of the semiconductor equipment.
In order that the above-recited objects, features and advantages of the present application will become more readily apparent, a more particular description of the application will be rendered by reference to the appended drawings and appended detailed description.
Referring to fig. 1, fig. 1 is a schematic flow chart of a surface coating method of a semiconductor device according to an embodiment of the present application, where the surface coating method includes:
step S11: providing an equipment body to be coated;
In the embodiment of the application, the semiconductor equipment comprises film deposition equipment, a plasma etching machine and other equipment. The equipment body comprises any workpiece which needs to be contacted with the reaction gas or plasma in the semiconductor equipment, such as a spray head, a gas pipeline, a reaction cavity and the like. The embodiment of the application is not limited to the specific mode of the semiconductor device and the device body.
Step S12: forming a first protective layer on the surface of the equipment body; the first protective layer at least comprises a first sub-protective layer formed based on an atomic layer deposition process.
The atomic layer deposition process is a special chemical vapor deposition process for single-layer atomic growth, and the film growth process can be performed in a low-temperature and low-pressure environment at 450 ℃. Unlike common CVD, the precursor of chemical reaction in the atomic layer deposition process does not decompose before contacting the surface of the device body to be coated, but after being adsorbed onto the surface of the device body, the precursor of chemical reaction undergoes chemical decomposition reaction on the surface of the device body, and the chemical components formed by the decomposition uniformly cover the whole surface of the device body to form an atomic layer film. Therefore, the atomic layer deposition process can form a uniform multi-atomic layer stack embedded long thin film on an apparatus body having a complex surface (e.g., an apparatus body having a complex geometry surface, an inner and outer wall of a cylindrical tube, and an inner surface of a fine air hole) by controlling the distribution of the reaction gas so that the chemically reactive precursor thereof can sufficiently diffuse into contact with the surface of the member and purging for a sufficient time to remove the remaining precursor. The atomic layer growth film is formed by decomposing the precursor, so that the film formed by the atomic layer deposition process has compact structure, can form the omnibearing surface coverage of the equipment body, and has good interface binding force and tissue thermal stability.
Optionally, in an embodiment of the present application, a method for forming a first sub-protection layer includes: and sequentially forming a plurality of atomic layer films on the surface of the equipment body by adopting an atomic layer deposition process, wherein the atomic layer films are used as a first sub-protection layer. The thickness of the first sub-protective layer can be precisely controlled by controlling the number of cycles of depositing the atomic layer film.
Referring to fig. 2, fig. 2 is a flowchart of a method for forming a first sub-protection layer according to an embodiment of the present application, where the first sub-protection layer includes a plurality of atomic layer films, and the method for forming the first sub-protection layer includes:
Step S21: forming a first atomic layer film based on saturated chemisorption and reaction of the first precursor with the surface of the device body;
step S22: and forming another atomic layer film based on saturated chemical adsorption and reaction of the second precursor and the surface of the previous atomic layer film.
Wherein the precursor for forming the previous atomic layer film is purged and discharged before forming the next atomic layer film.
The number of cycles of depositing the atomic layer film is set based on the requirements, and the thickness of the first sub-protective layer can be accurately controlled.
Referring to fig. 3 to fig. 6, fig. 3 to fig. 6 are schematic diagrams of a first sub-protection layer manufacturing method according to an embodiment of the present application in different process steps, where the manufacturing method includes:
first, as shown in FIG. 3, a first precursor 11 is introduced to form a first atomic layer film 12 based on saturated chemisorption and reaction of the first precursor 11 with the surface of the device body 13
Then, as shown in fig. 4, the first precursor 11 is discharged by purging.
As further shown in fig. 5, the second precursor 14 is introduced to form a second atomic layer film 15 based on saturated chemisorption and reaction of the second precursor 14 with the surface of the first atomic layer film 12.
As further shown in fig. 6, the second precursor 14 is discharged by purging.
In the method shown in fig. 3 to 6, a method of forming the first sub-protective layer is illustrated by taking the formation of two atomic layer thin films as an example. As described above, in the embodiment of the present application, the number of cycles for depositing the atomic layer film may be set based on the requirement, so that the thickness of the first sub-protective layer may be accurately controlled. The precursors used for different atomic layer films may be the same or different, and the precursor components are set based on the reaction requirements, which is not limited in the embodiment of the present application.
In the embodiment of the application, the first protection layer at least comprises a first sub-protection layer formed based on an atomic layer deposition process and is used for protecting the surface of the equipment body from being corroded by the reaction gas and plasma. The first sub-protective layer formed by the atomic layer deposition process has the following advantages relative to the conventional methods of CVD, PVD and the like for limiting coating: the first sub-protective layer is a pinhole-free compact film formed by low-temperature deposition, so that the corrosion of reaction gas and plasma can be effectively avoided; the film can be formed on the surfaces of various equipment bodies with complex shapes in a large area in an omnibearing manner; the composition and thickness of the film can be accurately controlled, and the thickness variation range can be increased from 1nm to more than 10 mu m; the film forming penetrability is excellent, and the width-depth ratio of the film can reach 1: over 200, film forming is convenient for the inner surfaces of deep holes and pipelines; the film has good binding force with the equipment body and good high temperature resistance.
In order to improve the interfacial binding force of the first sub-protective layer on the device body, the method further comprises the step of pre-treating the surface of the device body before forming the first protective layer, so that the surface of the device body is subjected to modification treatment, and the attachment stability of the first sub-protective layer on the surface of the device body is improved.
In order to improve the interfacial binding force of the first sub-protective layer on the surface of the equipment body, the method further comprises the step of preprocessing the surface of the equipment body before the first sub-protective layer is formed, so that the thickness of one side part of the equipment body to be coated is converted into a buffer transition layer, and the first sub-protective layer has good adhesion stability on the buffer transition layer, so that the adhesion stability of the first sub-protective layer on the surface of the equipment body is improved.
Referring to fig. 7, fig. 7 is a schematic flow chart of another surface coating method of a semiconductor device according to an embodiment of the present application, where the surface coating method includes:
step S31: providing a device body to be coated.
Step S32: and (3) preprocessing the surface of the equipment body to improve the adhesion stability of the first sub-protective layer on the surface of the equipment body.
Step S33: forming a first protective layer on the surface of the equipment body; wherein the first protective layer comprises at least a first sub-protective layer formed based on an atomic layer deposition process (ALD).
Based on the method shown in fig. 1, in the method shown in fig. 7, the surface of the device body is pretreated before the first protective layer is formed, so that the adhesion stability of the first sub-protective layer on the surface of the device body can be improved.
Optionally, the method for preprocessing the surface of the device body includes: and modifying the surface of the equipment body by adopting a first plasma immersion process, so that a gradual transition layer with gradually changed doping components is formed in the surface of the equipment body.
The first plasma immersion process is adopted, so that the equipment body is in a plasma immersion environment, the surface of the equipment body is subjected to modification treatment, the omnibearing surface modification can be realized, and the method can be suitable for the surface modification of the equipment body with the surface with complex geometric appearance, the inner and outer walls of a cylindrical tube and the inner surface of a tiny air hole, so that the surface binding force of the first protective layer is improved.
Compared with the method for forming the protective layer on the surface of the equipment body based on the atomic layer deposition process directly, the method shown in fig. 7 combines the plasma immersion process and the atomic layer deposition process, can perform high-quality all-dimensional film plating on the surface of the equipment body, and the first protective layer formed on the surface of the equipment body has better interface bonding force and controllable compactness with the surface of the equipment body within a certain thickness.
The plasma immersion process has a process principle shown in fig. 8.
Referring to fig. 8, fig. 8 is a schematic diagram of a plasma immersion process according to an embodiment of the present application, in which an apparatus body 13 to be processed is placed in a reaction chamber 21 of a plasma immersion apparatus, and after a vacuum is pumped through a vacuum port 211, a reaction gas is input into the reaction chamber 21 through a reaction gas supply device 23. The reaction chamber 21 is connected to one or more external plasma generating power sources 22, and the reaction gas in the reaction chamber 21 is excited or ignited by the external plasma generating power sources 22 to form plasma. The apparatus body 13 will be surrounded by the formed plasma immersion. The device body 13 is placed on the tray, the device body 13 is provided with pulse bias based on an external signal source 24 connected with the tray, and the charged ions and active chemical components in the plasma surrounding the device body 13 are interacted with the surface of the device body in all directions along with the density and bias change of the plasma.
The inventors have found that in a plasma immersion process, different process effects can be achieved by adjusting the pulse bias. Under the condition of ultra-high pulse bias (more than 30 kV), the ion implantation (Plasma immersion ion implantation, PIII for short) in the surface of the workpiece can be performed in an omnibearing manner; in a proper bias range (5 kV-35 kV), the surface alloying (Plasma immersion ion alloying, PIIA for short) or surface doping (Plasma immersion ion doping, PIID for short) of the workpiece can be realized; under lower negative bias (< 15 kV), the omnibearing coating (Plasma immersion ion deposition, PIID for short) on the surface of the workpiece can be realized; at lower bias (< 1 kV), energy-carrying ion bombardment cleaning (Plasma immersion ion cleaning, PIIC for short) of the workpiece surface can be performed. In addition, because PIID is subjected to omnibearing film plating on the surface of a workpiece through charged ions under a lower bias, PIID also has the function of ion beam assisted deposition (Ion BeamAssisted Deposition, abbreviated as IBAD) and forms a compact film structure, and can form a film on the surface of the workpiece at a low temperature (< 300 ℃).
Because PIIP has the functions, PIIP can perform all-round surface treatment on the surfaces of a plurality of different materials (such as metal, plastic, ceramic and the like), and a film formed on the surface of the equipment body has very good interfacial bonding force. This is because PIIP can form a chemically mild interfacial transition layer on the surface of the workpiece.
Although the PIIP is difficult to form a uniform modified layer on the inner surface of the deep hole due to the limitation of gas diffusion and plasma electric field distribution, for some non-penetrating blind holes with smaller diameters (less than 1 mm), the technical scheme combines the non-penetrating blind holes with an atomic layer deposition process, the first sub-protection prepared by the atomic layer process can realize omnibearing film protection, the surface pretreatment based on the PIIP can further improve the interface binding force of the first sub-protection layer on the surface of the equipment body to a certain extent. Also in semiconductor devices, the device body for containing the reactant gases and plasma generally does not have blind holes of smaller diameter.
Referring to fig. 9, fig. 9 is a schematic diagram of a modification treatment of a surface of an apparatus body according to an embodiment of the present application, where a plasma 10 is controlled by a pulse bias to modify an apparatus body 13. Based on the above description, by adjusting the pulse bias in the PIIP process, different modification treatments of the surface of the apparatus body can be realized, and the apparatus body 13 includes: the first injection region, the second injection region and the surface film. The doping components in the first injection region, the second injection region and the surface film are sequentially increased. The first injection region is the PIII doping process, the second injection region is the PIIA doping process or the surface alloying process, and the surface film is the PIID coating process. The doping depths of the first implantation region and the second implantation region in the direction are sequentially reduced, and the concentration of the doping components is sequentially increased, so that the surface of the device body 13 is provided with a gradual transition layer with increasing doping components, and the interface binding force of the subsequently formed first sub-protection layer on the surface of the device body can be improved.
Based on the above description, in the surface coating method provided by the embodiment of the present application, a method for modifying the surface of the apparatus body by using a first plasma immersion process is shown in fig. 10.
Referring to fig. 10, fig. 10 is a flowchart of a method for modifying a surface of an apparatus body according to an embodiment of the present application, where the method includes:
step S41: ion implantation of a first depth is performed in the surface of the equipment body under a first pulse bias;
Step S42: performing ion implantation of a second depth into the surface of the device body and/or performing surface alloying of the device body under a second pulse bias;
Wherein the second depth is less than the first depth.
The first injection region can be formed in the surface of the equipment body based on the first pulse bias voltage, and the second injection region or surface metallization can be formed in the surface of the equipment body based on the second pulse bias voltage, so that a gradual transition layer with increasing doping components is formed in the surface of the equipment body, and the interface binding force of the subsequently formed first sub-protection layer on the surface of the equipment body is improved. And the buffer transition layer not only can improve the interface binding force of the first sub-protective layer on the equipment body, but also can further increase the corrosion resistance and the high temperature resistance of the surface of the equipment body.
In other modes, the surface of the device body is modified, and a doped layer can be formed in the surface of the device body based on a plasma immersion process, wherein the doped layer can be a doped region with uniform doping components formed based on a constant pulse bias, such as a doped region formed based on a PIII process, a doped region formed based on PIIA, or a doped region comprising the first doped region and the second doped region, and the doping components of the two doped regions are gradually changed. Wherein, the gradual change of doping component refers to the gradual change of the concentration of doping element. In this way, the interfacial bonding force of the first sub-protective layer can also be improved to some extent.
In the embodiment of the application, compared with the scheme of forming the first protective layer on the surface of the equipment body based on the independent atomic layer deposition process, the scheme of forming the first protective layer on the surface of the equipment body based on the plasma immersion process and the atomic layer deposition process can improve the interface binding force between the first protective layer and the equipment body based on the buffer transition layer formed on the surface of the equipment body by the plasma immersion process. Compared with a plasma immersion process, the atomic layer deposition process has higher film coverage width-to-depth ratio, so that the film coverage with uniform thickness is easier to form on the surface of the equipment body with a complex structure and an inner hole, and the film thickness control precision is high (the thickness variation is generally less than 5%).
Optionally, based on any one of the foregoing manners, in the surface coating method provided by the embodiment of the present application, a method for forming a first protection layer further includes: and forming a second sub-protective layer on the surface of the first sub-protective layer by adopting a second plasma immersion process. The protective layer comprises a first sub-protective layer and a second sub-protective layer, and the device body can be subjected to corrosion protection through the protective layer under the condition that the first sub-protective layer with smaller thickness is adopted. Wherein the thickness of the second sub-protective layer may be 50nm-15 μm. Furthermore, when the thickness of the second sub-protective layer is set to be 500nm-1 μm, the first protective layer can achieve better corrosion resistance and protection effects.
Since the atomic layer deposition process forms a thin film at a relatively low speed and the cost increases rapidly as the thickness of the thin film increases, the thickness of the first sub-protective layer formed based on the atomic layer deposition process is generally relatively thin, and the thickness of the first sub-protective layer is less than 2000nm. In some cases, the first sub-protective layer has a thickness less than or equal to 500nm. If the thickness of the first sub-protective layer is too large, not only the manufacturing cost is greatly increased, but also the thin film crystal grains become coarse, and the surface structure becomes coarse. In order to improve the quality of the omnibearing protection layer on the surface of the equipment body and expand the application range of the omnibearing protection layer, the embodiment of the application sets a second sub-protection layer prepared based on a plasma immersion process on the first sub-protection layer so as to increase the thickness of the first protection layer, thus forming a thinner first sub-protection layer based on an atomic layer deposition process and realizing better corrosion resistance protection effect.
Optionally, a second sub-protective layer is formed on the surface of the first sub-protective layer by adopting a second plasma immersion process, including: and under the negative bias less than 15kV, performing omnibearing film plating on the surface of the equipment body provided with the first sub-protective layer to form a second sub-protective layer. At this time, a surface film layer can be formed on the surface of the device body based on the PIID process described above.
In order to further improve the corrosion resistance of the equipment body, the surface coating method further comprises the following steps: forming a second protective layer on the surface of the first protective layer; the thickness of the second protective layer may be greater than the thickness of the first protective layer.
Optionally, the method for forming the second protection layer includes: and forming a second protective layer by adopting a plasma enhanced physical vapor deposition process. For the equipment body with the smaller-diameter air holes, the thinner first protective layer covers the surface of the equipment body in an all-around mode and comprises the inner walls of the air holes, and the thicker second protective layer covers the surface outside the air holes and the inner walls near the opening parts of the air holes.
The plasma enhanced physical vapor deposition process is essentially a surface thin film deposition process performed by a combination of a physical vapor deposition process and a plasma enhanced process. The PVD process may be performed by vacuum evaporation, ion bombardment sputtering, magnetron sputtering, etc., and the plasma enhancement function may be achieved by ion bombardment in plasma and ion beam bombardment. Due to the bombardment effect of ions, weak atomic bonds in the film growth process can be broken, and the atomic surface is promoted to diffuse to form compact crystalline or amorphous tissues with consistent orientation. Therefore, compared with films prepared by other film deposition processes such as evaporation, plasma spraying and the like, the film formed by the plasma enhanced physical vapor deposition process has compact structure and greatly enhanced plasma etching resistance. In addition, the physical vapor deposition process and the plasma process are combined, so that the plasma enhanced physical vapor deposition process can be performed on the surface of the equipment body at a lower temperature (< 200 ℃) and the thickness of the film can reach more than 150 mu m, and the method is very suitable for depositing ceramic films with enough thickness (> 20 mu m) such as Y2O3 and the like on the surface of the equipment body made of aluminum alloy materials.
The surface coating method according to the embodiment of the application is further described below by taking the equipment body as a spray header as an example.
Referring to fig. 11 to 13, fig. 11 is a plan view of a device body, fig. 12 is a cut-away view of the device body shown in fig. 11, fig. 13 is a partially enlarged view of the device body shown in fig. 11, and fig. 11 to 13 show a manner in which the device body 13 is a shower head having air holes 131, and the surface of the device body 13 is not provided with a protective layer, so that the surface of the device body 13 is easily corroded by a reaction gas and plasma.
Wherein, the thickness of the spray header is generally 3mm-100mm, the diameter of the air hole 131 can be 0.04mm-100mm, and the diameter of the air hole 131 of part of the spray header can be more than 100mm. In the embodiment of the present application, the diameter of the air hole 131 is illustrated as uniform, and in other ways, the air hole 131 may be formed by connecting pipes with different diameters.
Referring to fig. 14, fig. 14 is a partial enlarged view of an apparatus body formed with a corrosion-resistant protective layer according to an embodiment of the present application, in which, based on the mode shown in fig. 11 to 13, in the mode shown in fig. 14, a first protective layer 31 is formed on the surface of the apparatus body 13, the first protective layer 31 includes a first sub-protective layer 311, and the film forming penetration of the first sub-protective layer 311 formed based on an atomic layer deposition process is excellent, and the aspect ratio of the film formation can reach 1:200 or more, an omnibearing thin film cover can be formed on the surface of the equipment body 13, and a good corrosion-resistant protective layer can be formed.
Referring to fig. 15, fig. 15 is a partial enlarged view of another apparatus body having a corrosion-resistant protective layer formed according to a plating method according to an embodiment of the present application, in which, based on the manner shown in fig. 14, in the manner shown in fig. 15, the surface of the apparatus body 13 is pretreated before the formation of the first protective layer 31, so as to form a modified layer 32, so as to improve the interfacial bonding force of the first protective layer 31 on the apparatus body 13.
Referring to fig. 16, fig. 16 is a partial enlarged view of an apparatus body having a corrosion-resistant protective layer formed according to still another embodiment of the plating method of the present application, in which a second sub-protective layer 312 is further formed on the surface of a first sub-protective layer 311 in the manner shown in fig. 16 on the basis of the manner shown in fig. 15. The first sub-protective layer 311 is limited to an atomic layer deposition process, and has a low film formation speed, and cannot form a thin film with a large thickness. In this way, the second sub-protective layer 312 is further formed on the surface of the first sub-protective layer 311, so that better corrosion resistance can be achieved based on the first sub-protective layer 311 with a thinner thickness.
Referring to fig. 17, fig. 17 is a partially enlarged view of an apparatus body having a corrosion-resistant protective layer formed thereon according to still another embodiment of the plating method of the present application, in which a second protective layer 33 prepared based on a PEPVD process is further formed on the surface of the first protective layer 31 in the manner shown in fig. 17 on the basis of the manner shown in fig. 16.
As can be seen from the above description, according to the surface coating method of the present application, the modified layer 32 is formed on the surface of the device body 13 based on the plasma immersion process, and the modified layer 32 is a graded transition layer with graded doping components for enhancing the interfacial bonding force of the subsequently formed first sub-protective layer 311. The modified layer 32 formed by the plasma immersion process is convenient for forming a dense first sub-protective layer 311. The first sub-protective layer 311 formed by the atomic layer deposition process has a high aspect ratio of film coverage compared to the plasma immersion process. Therefore, according to the surface coating method provided by the technical scheme of the application, the first sub-protective layer 311 with uniform thickness and composition is formed on the modified layer 32 formed by the plasma immersion process by adopting the atomic layer deposition process, so that the outer surface of the whole equipment body 13 and the inner surface of the air hole 131 can be covered. In order to ensure that the surface protection layer finally formed in an omnibearing coverage has a fine and compact tissue structure, a second sub-protection layer 312 is prepared on the first sub-protection layer 311 based on a plasma immersion process, so as to further increase the thickness of the first protection layer 31. The surface protection layer prepared based on the method is very suitable for the surface protection of flat plate workpieces used in PVD, CVD and other semiconductor coating equipment, such as a spray header prepared from aluminum alloy.
In the embodiment of the present application, the first protective layer 31 includes a ceramic film to form an omnidirectionally covered ceramic protective film on the surface of the device body 13. The first sub-protective layer 311 is a ceramic film. When the first protective layer 31 further includes the second sub-protective layer 312, the second sub-protective layer 312 is a ceramic film.
In view of enhancing the structural stability of the first protective layer 31 formed on the surface of the apparatus body 13 in an all-around manner and satisfying the operational requirements of the use environment, it is preferable to deposit a plasma corrosion resistant film having a chemical composition and a structural structure similar to those of the apparatus body 13 as the first sub-protective layer 311 bonded to the apparatus body 13 on the surface of the apparatus body 13. When the first sub-protective layer 311 is a ceramic film, the alloy element in the ceramic film is the same as the material of the device body 13, and the ceramic film has smaller interface deformation stress when deposited on the surface of the device body 13, which is beneficial to improving the tissue stability of the formed ceramic film. For example, when the apparatus body 13 of aluminum alloy is employed, an Al2O3 thin film is deposited on the surface thereof as the first sub-protective layer 311; when the device body 13 of the silicon substrate is employed, a SiC thin film is deposited as the first sub-protective layer 311 on the surface thereof; when the device body 13 of yttrium alloy is used, a Y2O3、YF3 or YOF film is deposited on the surface thereof as the first sub-protective layer 311.
When the first sub-protective layer 311 is a ceramic film, the alloy elements in the ceramic film are the same as the material of the device body 13, so that the interface binding force between the ceramic film and the device body 13 can be improved, and the amorphous structure characteristic of the ceramic film can effectively prevent microelements in the device body 13 from diffusing to the surface of the ceramic film, thereby reducing the microelement pollution caused by the device body 13 in the use process of the semiconductor device. For the spray heads made of aluminum alloy materials which are usually used under the condition of higher temperature, the working temperature of the spray heads used for PVD equipment and CVD equipment can be 150 ℃ or even above 300 ℃, and the amorphous omnibearing covering ceramic film can be used as the first sub-protective layer 311, so that the effect of reducing trace element pollution can be achieved well.
In the semiconductor device according to the embodiment of the present application, the first sub-protective layer 311 has a multi-layer film structure, and the required protective device body 13 has a very excellent combination of properties in different use environments by setting the film characteristics and the order of formation.
Taking the device body 13 made of aluminum alloy as an example, the first sub-protection layer 311 includes an alumina ceramic film. A doped layer may be formed by oxygen ion implantation into the surface of the device body 13 as a modified layer 32 to enhance the interfacial bonding force of the subsequently formed aluminum oxide film. After the modified layer 32 is formed on the surface of the equipment body 13, an amorphous aluminum oxide ceramic film is formed on the surface of the modified layer 32, so that not only can the corrosion resistance of the surface of the equipment body 13 made of aluminum alloy be enhanced, but also the alloy elements in the aluminum alloy can be prevented from diffusing to the surface, the target tissue stability of the surface of the equipment body 13 is enhanced, and the pollution of trace elements is reduced.
The first sub-protective layer 311 includes at least a first ALD film on the surface of the device body 13 and a second ALD film on the surface of the first ALD film, the first ALD film being in contact with the surface of the device body.
The second ALD film has a corrosion resistance greater than that of the first ALD film and a similar coefficient of thermal expansion. In this way, the corrosion resistance of the first sub-protective layer 311 can be further enhanced by the second ALD thin film. Taking the first ALD film as an alumina material and the second ALD film as an yttria material, the material properties of the two are shown in table 1 below.
TABLE 1
In Table 1, the thermal expansion coefficients of the materials at 200-1000℃are shown as thermal conductivity coefficients at 20 ℃. As shown in Table 1, the coefficients of thermal expansion of alumina and yttria are very close, whereas yttria has much higher resistance to plasma erosion than alumina in different plasma environments (e.g., containing O2, F, cl, HBr, etc.). Therefore, the yttrium oxide film is deposited on the surface of the aluminum oxide film, so that the corrosion resistance of the first protective layer 31 can be further enhanced, and the process stability of the equipment body 13 (such as a spray header) and the application range in different semiconductor equipment can be improved.
In order to further increase the bonding force between the second ALD film and the first ALD film, a transition layer may be formed therebetween. Taking the first ALD film as amorphous alumina and the second ALD film as crystalline yttria as an example, the transition layer between the first ALD film and the second ALD film may be a crystalline alumina film, where the multi-layer film structure of the first sub-protective layer 311 includes: amorphous alumina/crystalline state alumina/crystalline yttria.
In order to improve other characteristics of the first sub-protection layer 311, such as thermal conductivity and electrical conductivity, a thermal/electrical conductive film may be added to the first sub-protection layer 311, so that the first sub-protection layer 311 has better thermal/electrical conductivity while achieving corrosion resistance, thereby forming a multifunctional first sub-protection layer 311. The elemental thin film in the first sub-protective layer 311 may also be ion implanted to change the thin film properties. The thickness of the first sub-protective layer 311 and the combination of the thicknesses of different films can be set according to different process conditions and properties of the film materials, which is not limited in the embodiment of the present application.
As can be seen from the above description, the surface coating method provided by the technical scheme of the application can be used for surface coating of workpieces with complex structure surfaces in semiconductor equipment, such as surface coating of spray heads, cylindrical workpieces, gas pipe workpieces and the like, and can realize omnibearing coating of the surfaces of equipment bodies by combining an atomic layer deposition process and a plasma immersion process, thereby effectively solving the problem of surface protection of the workpieces with complex structure surfaces in the semiconductor equipment.
The development of the surface coating method utilizes the versatility of a plasma immersion process, improves the binding force and the surface compactness of an omnibearing film based on PIII and PIID, can effectively improve the quality of the film formed by single ALD, enhances the tissue stability of the omnibearing film, reduces the pollution of particles and trace elements generated by the corrosion of the surfaces of workpieces such as workpieces with protected cavities by reaction gas or plasma, and improves the process stability of semiconductor equipment.
The surface coating method can prepare the multi-layer atomic layer film on the surface of the equipment body by utilizing the stability and process controllability of the ALD process according to the working environment requirements of the semiconductor equipment and the mutual matching compatibility of the tissue structures and the performances of different film materials; through the design of film materials, an interface layer with strong binding force, a ceramic film with plasma corrosion resistance on the surface and a multi-film structure with special functions (heat resistance/heat conduction/electric conduction and the like) are formed on the surface of the equipment body so as to meet the working requirements of different semiconductor equipment.
Further, according to the plasma etching characteristics of the semiconductor device and the PEPVD process, a second protective layer with larger thickness is deposited on the surface of the prepared omnibearing covered first protective layer, so that the plasma etching resistance characteristics are further improved, and the key service life and the process stability of plasma etching are improved.
Based on the foregoing embodiment of the surface coating method, another embodiment of the present application further provides a semiconductor device, where the semiconductor device includes, but is not limited to, a thin film deposition device, a plasma etcher, and the like. The semiconductor device includes: the equipment body can be a flat-plate workpiece in the semiconductor equipment, such as a spray header, other transmission pipelines, a reaction chamber and the like.
In connection with the embodiment shown in fig. 14, the semiconductor device includes: the device body 13 covers the first protective layer 31 of the device body 13, and the first protective layer 31 includes at least a first sub-protective layer 311 formed based on an atomic layer deposition process.
Alternatively, in the embodiment of the present application, the first sub-protective layer 311 includes a plurality of atomic layer films sequentially stacked. The thickness of the first sub-protective layer 311 can be precisely controlled based on the set number of atomic layer depositions.
In connection with the embodiment shown in fig. 15, the surface of the apparatus body is subjected to modification treatment so that a portion having a certain thickness in the surface of the apparatus body serves as a modification layer 32 to improve the adhesion stability of the first sub-protective layer 311 on the surface of the apparatus body 13.
In connection with the embodiment shown in fig. 16, the first protective layer 31 further includes: a second sub-protective layer 312 on the surface of the first sub-protective layer 311; the second sub-protective layer 312 is a film formed by a plasma immersion process.
In the embodiment of the present application, the first protective layer 31 includes a ceramic film, so that an omnidirectionally covered ceramic protective film is formed on the surface of the device body 13. The first sub-protective layer 311 may be a ceramic film. When the first protective layer 31 further includes the second sub-protective layer 312, the second sub-protective layer 312 is a ceramic film.
Wherein, the material of the ceramic film comprises: al2O3、Y2O3、YF3, YOF (one or more of Y5O4F7)、ZrO2、Er2O3、SiC、SiO2、HfO2、Si3N4、AlN、B2O3、Nd2O3、Nb2O5、CeO2、Sm2O3、Yb2O3,Y3Al5O12(YAG)、Er3Al5O12(EAG)、Y4Al2O9(YAM)、YAlO3(YAP)、Er4Al2O9(EAM) and ErAlO3 (EAP), or composite ceramic films based on these ceramic materials, are commonly characterized by plasma corrosion resistance, stable performance, and corrosion resistance and stability far superior to aluminum alloy workpiece materials.
In connection with the embodiment shown in fig. 17, the semiconductor device further includes: a second protective layer 33 on the surface of the first protective layer 31; optionally, the second protective layer 33 is a plasma enhanced physical vapor deposited film.
Wherein, the thickness of the second protection layer 33 may be greater than the thickness of the first protection layer 31. Alternatively, the thickness of the second protection layer 33 may be smaller than that of the first protection layer 31 by setting the coating time of the coating process.
Wherein the thickness of the first protective layer 31 is less than 25 μm and the thickness of the second protective layer 33 is greater than 10 μm.
Optionally, the second protective layer 33 is a ceramic film, and the material of the ceramic film may be as described above, which is not described herein.
The thickness of the first protective layer 31 prepared based on the atomic layer deposition process and based on the plasma immersion process is generally thin, in some cases less than 10 μm, even less than 2 μm. The first protective layer 31 may be etched by plasma due to the thin thickness in the plasma etching process. This problem can be solved by adding a second protective layer 33 having a large thickness on the surface of the first protective layer 31.
The second protective layer 33 is a dense plasma corrosion resistant film prepared based on PEPVD process, and has a thickness of more than 10 μm, for example, it may be set to a thickness of 20 μm to 150 μm. The second protective layer 33 prepared based on the PEPVD process has good compactness, no defect and plasma corrosion resistance.
In fig. 17, the apparatus body 13 is illustrated as a shower head, the shower head is made of an aluminum alloy, after the first protective layer 31 is formed on the surface of the shower head, a thicker second protective layer 33 is deposited by PEPVD, and the material 32 of the second protective layer 33 may be Y2O3 or YF3. The showerhead face film layer structure may include: the modified layer 32 prepared based on the PIIP process, amorphous aluminum oxide (amorphous Al2O3 or a-Al2O3) prepared based on the ALD process, crystalline yttrium oxide (Y2O3) and Y2O3 thick film prepared based on the PEVD process can enable the surface of the spray header, which is in contact with plasma, to have a thicker compact plasma corrosion resistant protective layer, so that the service life of the spray header is ensured. The inner wall of the shower nozzle air hole can be protected by the thinner first protection layer 31 based on omnibearing coverage, so that the corrosion of reaction gas is avoided, and the pollution of metal and particles can be avoided during the operation of the shower nozzle. Therefore, when the technical scheme of the application is used for the spray header, the long-time process stability of the semiconductor equipment using the spray header can be obviously improved, thereby achieving the purpose of improving the production efficiency.
In the present specification, each embodiment is described in a progressive manner, or a parallel manner, or a combination of progressive and parallel manners, and each embodiment is mainly described as a difference from other embodiments, and identical and similar parts between the embodiments are all enough to refer to each other. The semiconductor device disclosed in the embodiment corresponds to the surface coating method disclosed in the embodiment, so that the description is relatively simple, and the relevant points are described in the relevant parts of the surface coating method.
It should be noted that in the description of the present application, it is to be understood that the drawings and descriptions of the embodiments are illustrative and not restrictive. Like diagramming marks throughout the embodiments of the specification identify like structures. In addition, the drawings may exaggerate the thicknesses of some layers, films, panels, regions, etc. for understanding and ease of description. It will also be understood that when an element such as a layer, film, region or substrate is referred to as being "on" another element, it can be directly on the other element or intervening elements may be present. In addition, "on …" refers to positioning an element on or under another element, but not essentially on the upper side of the other element according to the direction of gravity.
The terms "upper," "lower," "top," "bottom," "inner," "outer," and the like are used for convenience in describing and simplifying the description based on the orientation or positional relationship shown in the drawings, and do not denote or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the application. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present.
It is further noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that an article or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such article or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in an article or device comprising the element.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.