Method for forming thin film and apparatus for processing substrate therefor
Patent Information
- Authority / Receiving Office
- TW · TW
- Patent Type
- Patents
- Current Assignee / Owner
- WONIK IPS CO LTD
- Filing Date
- 2023-12-07
- Publication Date
- 2026-08-01
Smart Images
Figure TWG2TB001903501_001 
Figure TWG2TB001903501_002 
Figure TWG2TB001903501_003
Abstract
Description
Thin Film Formation Method and Substrate Processing Apparatus for the Method The present invention relates to a thin film formation method and a substrate processing apparatus for the method. According to an embodiment of the thin film formation method, in a continuous deposition process of repeatedly forming a thin film on a substrate, it is possible to prevent a decrease in process quality caused by generation of particles inside the process chamber. This effect can be obtained by a process of strengthening the deposited thin film inside the process chamber by using DC plasma treatment. The DC plasma treatment can be performed by supplying a DC power source to an electrostatic chuck and forming plasma while supplying a purge gas. Generally, a deposition process of depositing a thin film on a substrate is performed using a substrate processing apparatus. The substrate processing apparatus may have a structure including: a process chamber, a gas injection unit for injecting gas into the process chamber, a gas supply unit for supplying gas to the gas injection unit, and a substrate placement unit such as an electrostatic chuck for placing a semiconductor substrate. The thin film deposition process uses a plasma enhanced chemical vapor deposition method (PECVD), a plasma enhanced atomic layer deposition method (PEALD), etc. The thin film deposition process employs a continuous thin film deposition process to expand mass production capacity. According to the continuous thin film deposition process, first, a substrate is placed on the substrate placement unit. Secondly, a thin film is deposited on the substrate. Then, the substrate on which the thin film has been deposited is transported outside the process chamber. After that, a series of processes including steps of placing a new substrate on the substrate placement unit, depositing a thin film, and transporting out the substrate are continuously repeated. In the continuous thin film deposition process as described above, reaction products are generated during the thin film deposition process. The generated reaction products are deposited on the surface of the thin film and the inner surface of the process chamber to form a deposited thin film. When the thin film formation process is continuously performed as described above, particles are generated by peeling of the reaction products from the deposited thin film. Such particles cause poor deposition processes and adhere to the substrate, reducing the yield of semiconductor elements. Conventionally, a thin film deposition process has been performed for a certain time or a certain number of times. And the particle problem is improved by performing a cleaning process for cleaning the inside of the chamber. However, when the cleaning process cycle is too short, the cleaning frequency will increase, which will reduce the unit per equipment hour (UPEH) of each equipment. <<Technical Problems to be Solved>> According to an embodiment, the present invention provides a thin film formation method and a substrate processing apparatus that can prevent process defects caused by particles and improve the unit per equipment hour of each equipment. Specifically, the film forming method according to an embodiment of the present invention performs a purge process after transporting out the substrate. In the purge process, a DC power source is supplied to the electrostatic chuck, and at the same time, a robust process of DC plasma treatment is performed by supplying a purge gas and forming a plasma. Through the DC plasma treatment, the film deposited inside the process chamber is strengthened. Accordingly, in the process of continuously depositing a film, generation of particulate matter in the deposited film can be prevented, process defects can be prevented, and the yield of each device of the substrate processing apparatus can be increased. 《Means for Solving the Problem》 The film forming method according to an embodiment of the present invention includes: a process chamber having a processing space for substrate processing; an electrostatic chuck disposed inside the processing space and on which the substrate is placed; a gas injection unit for injecting a gas toward the substrate; an electrostatic power supply unit for applying a DC power source to clamp the substrate by the electrostatic chuck; and a substrate processing apparatus for forming a plasma in the process chamber by applying an RF power source to a plasma power supply unit; and includes the following steps: a placement step of placing the substrate on the electrostatic chuck; a deposition step of applying a first DC power source to clamp the substrate, supplying a process gas and applying a first RF power source to form a first plasma, thereby depositing a film on the substrate; a transport-out step of transporting the substrate on which the film is deposited to the outside of the process chamber; and a DC plasma treatment step of applying a second DC power source, supplying a purge gas and applying a second RF power source to form a plasma to perform a strengthening treatment on the film formed inside the process chamber. According to one embodiment, the deposition step may be a process of depositing a film with a thickness of at least 10 to 20 μm. And the deposition step may be a process of forming a composite film on the substrate by alternately depositing a first film and a second film on the substrate at least once or more. Wherein, the first film and the second film are respectively any one of a silicon oxide film (SiO 2 layer), a silicon nitride film (SiN layer), a silicon oxynitride film (SiON layer), and a silicon oxycarbonitride film (SiOCN), and the compositions of the first film and the second film are different. More specifically, the first film may be a silicon oxide film (SiO 2 layer), and the second film may be a silicon nitride film (SiN layer). According to one embodiment, in the deposition step, at least one of an HF power source and a VHF power source is supplied to form a plasma to deposit the film. According to one embodiment, the voltage of the second DC power source is higher than the voltage of the first DC power source, and the second DC power source may be a positive voltage of 100 to 1000 V. According to one embodiment, the power of the second RF power supply is lower than that of the first RF power supply, and the power of the second RF power supply may be 50 to 500 W, and the DC plasma treatment step is performed for 5 to 180 seconds. According to one embodiment, the DC plasma treatment step may further include: a stabilization step of interrupting the application of the second DC power supply and the second RF power supply after performing a strengthening treatment on the deposited thin film. According to one embodiment, in the deposition step, a composite film may be formed by alternately depositing a first thin film and a second thin film at least once or more in an alternating manner of depositing a plurality of double thin films on the upper portion of the substrate. Alternatively, a deposition pattern is formed on the upper portion of the substrate, the deposition pattern includes a plurality of pattern blocks and high aspect ratio spaces respectively formed between the pattern blocks, and wherein, in the step of depositing a thin film on the substrate, a composite film is formed in the high aspect ratio space by alternately depositing a first thin film and a second thin film at least once or more in an alternating manner of depositing a plurality of double thin films on the upper portion of the substrate. In addition, a substrate processing apparatus according to an embodiment of the present invention includes: a process chamber having a processing space for substrate processing; an electrostatic chuck disposed inside the processing space and for placing the substrate; a gas injection unit for injecting gas toward the substrate; an electrostatic power supply unit for applying a DC power supply to clamp the substrate by the electrostatic chuck; a plasma power supply unit for applying an RF power supply to form a plasma in the process chamber; and a control unit for controlling the driving of the electrostatic chuck, the gas injection unit, the electrostatic power supply unit, and the plasma power supply unit, wherein the control of the control unit may include: performing applying a first DC power supply to the electrostatic chuck; after a deposition process of depositing a thin film on the substrate in the processing space by applying a first RF power supply to the electrostatic chuck or the gas injection unit, interrupting the application of the first DC power supply and the first RF power supply; transporting the substrate on which the thin film is deposited to the outside of the processing space, and then performing supplying a purge gas to the processing space; respectively applying a second DC power supply and a second RF power supply to form a plasma; and a DC plasma treatment for performing a strengthening treatment on the thin film formed inside the process chamber. According to one embodiment, the control of the control unit may include: after performing the DC plasma treatment, interrupting the application of the second DC power supply and the second RF power supply; placing the substrate on the electrostatic chuck, and applying the first DC power supply and the first RF power supply; and clamping a new substrate for depositing a thin film and supplying a process gas to form a plasma to deposit a thin film. 《Effects of the Invention》 In the thin film forming method according to an embodiment of the present invention, a thin film is deposited on a substrate, and while the substrate on which the thin film is deposited is transported outside the process chamber, DC plasma treatment is performed to control the cumulative thickness of the thin film deposited inside the process chamber and strengthen it. The DC plasma treatment is performed by supplying a DC power source to an electrostatic chuck and supplying a purge gas to form plasma. In various embodiments, in the process of continuously depositing a thin film by the DC plasma treatment, the deposited thin film can be strengthened, the deposited thin film can be prevented from generating particles, process defects can be prevented, and the yield of each device of the substrate processing apparatus can be improved. FIG. 1 is a timing chart showing an example of a conventional thin film forming method. Referring to FIG. 1, according to the prior art, a substrate to be deposited is placed on an electrostatic chuck provided inside a process chamber, and a DC voltage is applied to the electrostatic chuck to clamp the substrate (wafer chucking). Then, a process gas is supplied to the upper part of the substrate to form plasma and deposit (Depo) a thin film on the upper part of the substrate. Next, the application of the DC voltage to the electrostatic chuck is interrupted, the substrate is dechucked from the electrostatic chuck, and the substrate after depositing the thin film is transported (wafer out) outside the process chamber. After that, a purge gas is supplied to the inside of the process chamber to perform a purge step. Next, a new substrate to be deposited is placed (wafer in) in the process chamber, and a thin film is deposited (Depo) on the upper part of the substrate. And this thin film deposition process is continuously repeated to mass-produce semiconductor elements. Among them, the thin film forming process as described above can be a process of continuously performing a single thin film deposition process to form a thick块状 thin film. Or, the thin film forming process can also be a process of alternately depositing a first thin film and a second thin film to form a composite film. That is, the thin film can be a composite film including a first thin film and a second thin film. As described above, when a thin film is continuously formed by an in-situ process, reaction products in the thin film deposition process will adhere to the process chamber 110, the gas injection part 130, etc. and deposit a thin film on the surface. When a thin film with a thickness exceeding 10 μm is formed by the thin film deposition process, or when a thin film with a thickness of approximately 6 μm is continuously deposited two or more times (that is, even if a purge process is performed), particles are likely to be generated due to the reaction products peeling off from the deposited thin film. The particles are the cause of the deterioration of the quality of the deposited target thin film. The particles are more frequently generated in the composite film deposition process or the thin film stack formation process of depositing a plurality of thin films. According to the thin film forming method of an embodiment of the present invention, even when depositing a plurality of thin films continuously, generation of particles can be prevented. Accordingly, the thin film forming method of an embodiment of the present invention can prevent degradation of thin film quality and can increase the throughput of each device of a substrate processing apparatus. FIG. 2 is a timing chart showing the thin film forming method of an embodiment of the present invention; FIG. 3 is a flowchart showing the thin film forming method of an embodiment of the present invention. Referring to FIGS. 2 and 3, the thin film forming method of an embodiment of the present invention may include: a step (S10) of placing a substrate on an electrostatic chuck; a step (S20) of depositing a thin film on the substrate; a step (S30) of transporting the substrate on which the thin film is deposited to the outside of a process chamber; and a step (S40) of performing DC plasma processing on the process chamber. The thin film forming method may be performed by various conventional substrate processing apparatuses used for depositing thin films. The substrate processing apparatus may perform plasma enhanced chemical vapor deposition (PECVD), plasma enhanced atomic layer deposition (PEALD), or the like. Specifically, the structure of the substrate processing apparatus includes: a process chamber 110; an electrostatic chuck 120; a gas injection unit 130; an electrostatic power supply unit 140; a plasma power supply unit 150; and a control unit 160. The process chamber 110 has a processing space for substrate processing. The electrostatic chuck 120 is disposed inside the processing space and provides a space for placing the substrate S. The gas injection unit 130 functions to inject a process gas into the processing space. The electrostatic power supply unit 140 applies a DC power to the electrostatic chuck 120. The plasma power supply unit 150 applies an RF power to form plasma in the process chamber 110. The substrate processing apparatus will be described in detail in the following content. Each step of the thin film forming method of the embodiment will be described in detail below. First, in the step S10, a new substrate to be deposited is placed on the electrostatic chuck 120. The substrate S may be various conventional substrates used for depositing thin films. Specifically, the substrate S has a plate shape and may be made of glass or silicon, a polymer material that can carry static electricity. Specifically, the substrate is made of a material including crystalline silicon, silicon oxide, silicon oxynitride, silicon nitride, strained silicon, silicon germanium, tungsten, titanium nitride, doped or undoped polysilicon, doped or undoped silicon wafers, patterned or non-patterned wafers, SOI (silicon on insulator), carbon-doped silicon oxide, silicon nitride, doped silicon, germanium, gallium arsenide, glass, sapphire, a low-k dielectric, or a mixture thereof. The substrate may be a semiconductor substrate finished product for forming a given device or a bare wafer. Secondly, in the step (S20) of depositing a thin film on the substrate, a first DC power supply is applied to the electrostatic chuck 120 to chuck the substrate S. Then, a process gas is supplied to the processing space. In addition, a first RF power supply is applied to form a first plasma in the processing space, thereby depositing a thin film on the substrate S. In this step, various components of conventional thin films that can be deposited on a substrate can be deposited on the substrate S. Specifically, the thin film may be a single-layer thin film including any one of a silicon oxide film (SiO 2 layer), a silicon nitride film (SiN layer), a silicon oxynitride film (SiON layer), and a silicon oxycarbonitride film (SiOCN layer). The process gas may include various components of conventional gases used to form the thin film. Alternatively, in this step, a composite film may be formed on the substrate S. The composite film is formed by alternately depositing a first thin film and a second thin film on the substrate S at least once or more. The first thin film and the second thin film of the composite film are not limited to the number of stacked layers. The composite film may include one layer of the first thin film and the second thin film, respectively. Moreover, the composite film may have a structure in which a plurality of first thin films and a plurality of second thin films are alternately stacked. Specifically, the first thin film and the second thin film may be a silicon oxide film (SiO 2 layer), a silicon nitride film (SiN layer), a silicon oxynitride film (SiON layer), and a silicon oxycarbonitride film (SiOCN), respectively. And the components of the first thin film and the second thin film may be different. In particular, the first thin film may be a silicon oxide film (SiO 2 layer), while the second thin film may be a silicon nitride film (SiN layer). In addition, in this step, in order to deposit a thin film on the substrate S, a process gas is supplied through the gas injection unit 130, respectively. Then, a first RF power supply including at least one of a high frequency (HF) power supply and a very high frequency (VHF) power supply is applied to form a first plasma in the processing space to deposit a thin film on the substrate. In this step, a thin film with an average thickness of at least 1 to 100 μm can be formed. In particular, in this step, a thin film of 10 to 20 μm can be formed. In this step, even when continuously forming a thick film with the above-mentioned thickness, the phenomenon of particles generated due to the peeling of the deposited film in the process chamber can be prevented. Specifically, this step may be a process of continuously depositing the same thin film to form a thick块状 thin film, but is not limited thereto. In addition, this step may be a process of forming a composite film. By alternately depositing a plurality of double thin films on the upper part of the substrate, the first thin film and the second thin film are alternately deposited at least once or more to form the composite film. Wherein, the substrate may form a deposition pattern on the upper part including a plurality of pattern blocks and high aspect ratio spaces respectively formed between the pattern blocks. In this step, by alternately depositing a plurality of double thin films on the upper part of the substrate, the first thin film and the second thin film are alternately deposited at least once or more to form a composite film in the high aspect ratio space, and the high aspect ratio space is filled with the composite film. Wherein, the pattern blocks are formed by using a conventional mold composition of various components used for forming a composite film pattern on the substrate. Secondly, in the step (S30) of transporting the substrate with the deposited thin film outside the process chamber, the substrate S with the deposited thin film is transported outside the process chamber 110. In the step S30, the application of the first DC voltage to the electrostatic chuck is interrupted, and the substrate S with the deposited thin film is de-chucked and separated from the electrostatic chuck 120. And, the substrate separated from the electrostatic chuck is transported outside the process chamber 110. The transport of the substrate S can be performed by various conventional methods. Secondly, in the step S40, DC plasma treatment is performed. The DC plasma treatment is performed by the following method: First, a second DC power supply is applied to the electrostatic chuck 120 to supply a purge gas to the inside of the process chamber. At the same time, a second RF power supply is applied to form plasma, and a strengthening treatment is performed on the thin film deposited on the inner surface of the process chamber 110 and the surface of the gas injection part 130. In the step S40, ions are formed based on the plasma formed by applying the second RF power supply. And, a DC power supply with a positive voltage is applied to the electrostatic chuck. Accordingly, the gas injection part side is relatively negatively charged, and the positive charge is accelerated and moves toward the gas injection part 130 side. Accordingly, the density of the thin film deposited on the inner surface of the process chamber will be greatly increased to achieve strengthening, the reaction products are stabilized, and the generation of particles can be prevented. And, during the transport and placement of the substrate, a margin for the deposited thin film can be ensured. Accordingly, even if the reaction products are excessively deposited on the surfaces of the process chamber 100 and the gas injection part 300 to deposit a thick thin film, the reaction products are not easily peeled off from the deposited thin film. Therefore, the second DC power supply applied in step S40 can be the same as the first DC power supply applied in step S20 or the second DC power supply can be adjusted to have a higher voltage than the first DC power supply. In particular, the voltage of the second DC power supply can be higher than the voltage of the first DC power supply. The second DC power supply as described above can apply a positive voltage of 100 to 1000 V. Also, in this step, a second plasma is formed by applying a second RF power supply including at least one of a high frequency (HF) power supply and a very high frequency (VHF) power supply to perform a strengthening process. Also, the power of the second RF power supply can be the same as or lower than that of the first RF power supply. In particular, it can be controlled that the power of the second RF power supply is lower than the power of the first RF power supply. Specifically, the second RF power supply can supply power of 50 to 500 W. As described above, the voltages and powers of the second DC power supply and the second RF power supply are adjusted respectively compared with the first DC power supply and the first RF power supply, so that the deposited thin film is made stronger. Also, in this step, a strengthening process is performed for 5 to 180 seconds. In addition, after performing the strengthening process, a new deposition target substrate for depositing a thin film is placed on the electrostatic chuck to perform a thin film deposition process. In particular, regarding the strengthening process, the processing time can be selectively adjusted according to conditions. Also, the purge gas can use conventional inert gases such as argon (Ar) gas, nitrogen (N 2 ) gas, helium (He) gas, neon (Ne) gas, or a mixture thereof. Also, in this step, after performing the DC plasma processing step (S40), a new deposition target substrate for depositing a thin film is placed on the electrostatic chuck 120 to continuously perform thin film deposition. Also, in this step, after performing a strengthening process on the deposited thin film, a step of interrupting the application of the second DC power supply and the second RF power supply and stabilizing them can be performed, and then a new deposition target substrate is placed on the electrostatic chuck. In the method for forming a thin film according to the above-described embodiment, while the substrate on which the thin film is deposited is transported outside the process chamber, a DC power source is supplied to the electrostatic chuck. At the same time, a DC plasma process of supplying a purge gas to the process chamber and forming a plasma is performed to control the cumulative thickness of the thin film deposited inside the process chamber and strengthen it. Accordingly, in the process of continuously depositing a thin film, generation of particles in the deposited thin film can be prevented, process defects can be prevented, and the yield of each device of the substrate processing apparatus can be increased. In particular, the method for forming a thin film according to an embodiment of the present invention can also be applied to a bulk film deposition process of continuously depositing the same thin film, a composite film deposition process of alternately depositing a plurality of thin films having different compositions, and a process of filling a high aspect ratio space with a composite film. In addition, as the number of stacked layers increases, a thin film with high utilization rate and high quality can be formed. The substrate may have a structure in which a deposition pattern including a plurality of pattern blocks formed on the upper part and high aspect ratio spaces formed between the pattern blocks is formed. In the deposition step, the first thin film and the second thin film are alternately deposited at least once or more to fill the high aspect ratio space with a composite film. In addition, FIG. 4 is a schematic diagram showing a substrate processing apparatus according to an embodiment. Referring to FIG. 4, the substrate processing apparatus according to an embodiment of the present invention has a structure including a process chamber 110, an electrostatic chuck 120, a gas injection unit 130, an electrostatic power supply unit 140, a plasma power supply unit 150, and a control unit 160. The process chamber 110 has a processing space 112 for substrate processing. Specifically, the processing space 112 can be defined inside the process chamber 110. For example, the process chamber 110 can maintain airtightness, be connected to a vacuum chamber (not shown in the drawing) through an exhaust port, and be able to discharge the process gas inside the processing space 112 and adjust the vacuum degree inside the processing space 112. The process chamber 110 can adopt various shapes. For example, it can include a side wall portion defining the processing space 112 and a cover portion located at the upper end of the side wall portion. The electrostatic chuck 120 is disposed inside the processing space 112 and provides a space for placing the substrate S. Specifically, the electrostatic chuck 120 is disposed in the process chamber 110 opposite to the gas injection unit 130, and the substrate S is placed on its upper part to provide a clamping force to the substrate and fix the substrate. For this purpose, the electrostatic chuck 120 can include an electrostatic electrode 125 to apply an electrostatic force to the substrate S and fix it to its upper part. In addition, the electrostatic chuck 120 can further include a heater 127 for heating the substrate S, and can also include another power supply unit (not shown in the drawing) for supplying power to the heater 127. The shape of the electrostatic chuck 120 generally corresponds to the shape of the substrate S, but is not limited thereto. To stably place the substrate S, various shapes larger than the substrate S can be adopted. In addition, the electrostatic chuck 120 is connected to an external motor (not shown in the drawings) to achieve lifting. At this time, a bellows (not shown in the drawings) can be connected to maintain airtightness. Furthermore, since the substrate S is placed on the upper part of the electrostatic chuck 120, it can be referred to as a substrate placement part, a substrate holder, a base, etc. The gas injection unit 130 has the function of injecting a process gas into the processing space. Specifically, the gas injection unit 130 is disposed in the process chamber 110 to supply the process gas supplied from the outside of the process chamber 110 to the processing space 112. The gas injection unit 130 is disposed opposite to the electrostatic chuck 120 at the upper part of the process chamber 110, so as to inject the process gas onto the substrate S placed on the electrostatic chuck 120. The gas injection unit 130 may include: at least one inflow hole formed on the upper side or side to receive the process gas supplied from the outside; a plurality of injection holes formed downward toward the substrate S to inject the process gas onto the substrate S. Moreover, the gas injection unit 130 can have various forms such as a shower head form and a nozzle form. When the gas injection unit 130 is in the form of a shower head, the gas injection unit 130 is coupled to the process chamber 110 in a form covering the upper part of the process chamber 110. As an example, the gas injection unit 130 is coupled to the side wall part in the form of a cover of the process chamber 110. The electrostatic power supply unit 140 has the function of applying a DC power supply to clamp the substrate S by the electrostatic chuck 120. For this purpose, the electrostatic power supply unit 140 includes a DC power supply 142 to supply DC power to the electrostatic electrode 125. One end of the DC power supply 142 is connected to the grounding part, and the other end is electrically connected to the electrostatic electrode 125 through a node (n1) to supply DC power. The electrostatic power supply unit 140 may further include: a DC filter 145 disposed between the electrostatic electrode 125 and the DC power supply 142 to block the RF current from flowing into the DC power supply 142 through the electrostatic electrode 125. The DC filter 145 is configured in various forms and can block the RF current but allow the DC current to pass through. The plasma power supply unit 150 has the function of applying an RF power supply to form a plasma in the process chamber 110. Specifically, the plasma power supply unit 150 may include at least one RF power supply, and in order to form a plasma atmosphere inside the process chamber 110, at least one RF (radio frequency) power is applied to the process chamber 110. As an example, the plasma power supply unit 150 is connected to the gas injection unit 130 to apply RF power. In this case, the gas injection unit 130 may be referred to as a power supply electrode or an upper electrode. As another example, the plasma power supply unit 150 is connected to a bias electrode 129 provided at the lower part of the electrostatic chuck 120 for applying RF power to the electrostatic chuck 120 to form the electrostatic chuck 120. In this case, the electrostatic chuck 120 may be referred to as a lower electrode. Moreover, the plasma power supply unit 150 includes: an impedance matching unit 156, which is provided between the plasma power supply unit 150 and the gas injection unit 130 for impedance matching between the RF power supply and the process chamber 110. The plasma power supply unit 150 includes at least one or more RF power supplies. The RF power supply may include a first RF power supply 152 in a first frequency band and a second RF power supply 154 in a second frequency band greater than the first frequency band in order to control the plasma environment based on process conditions. The dual-frequency power supply composed of the first RF power supply 152 and the second RF power supply 154 can change the frequency band according to process conditions or process steps, thereby precisely controlling the process. Secondly, the control unit 160 functions to control the driving of the electrostatic chuck 120, the gas injection unit 130, the electrostatic power supply unit 140, and the plasma power supply unit 150. In particular, the control unit 160 performs a deposition step of depositing a thin film on the substrate S inside the process chamber 110, and interrupts the application of the first DC power supply and the first RF power supply. And the control unit 160 transports the substrate S on which the thin film is deposited to the outside of the process chamber 110. After that, the control unit 160 controls to apply a second DC power supply to the electrostatic chuck 120, apply a second RF power supply to form a plasma, and perform a strengthening process on the thin film deposited on the surface of the inside of the process chamber 110 and the gas injection unit 130. And after the control unit 160 performs the strengthening process of the deposited thin film as described above, it interrupts the application of the second DC power supply and the second RF power supply. And the control unit 160 controls to place the substrate on the electrostatic chuck 120. Secondly, the control unit 160 controls to apply a first DC power supply and a first RF power supply to clamp the substrate for depositing the thin film. Secondly, the control unit 160 controls to supply a process gas to form a plasma, thereby depositing a thin film. The present invention will be described in more detail with reference to the embodiments below. The embodiments described herein are merely specific examples of the present invention and do not limit the technical scope of the present invention. <Embodiment> First, a nitride film and an oxide film specimen are respectively attached to the gas injection part (i.e., the lower surface of the showerhead) provided inside the process chamber. Secondly, the substrate is placed on the electrostatic chuck, and a voltage is applied to the electrostatic chuck to clamp the substrate. And, a silicon nitride film and a silicon oxide film are sequentially deposited on the substrate. Secondly, the substrate on which the thin film is deposited is released from the chuck and separated from the electrostatic chuck. In addition, the separated substrate is transported outside the process chamber. After that, a new substrate for depositing the thin film is placed on the electrostatic chuck. Among them, during the process of transporting the substrate out and placing the new substrate, in order to transport the substrate out, the application of the electrostatic chuck voltage and the RF power supply is interrupted, and the substrate is released from the electrostatic chuck. During the process of transporting the substrate out, a DC power supply with a higher power and an RF power supply with a lower current are respectively applied to form a plasma compared with the DC power supply applied for performing the thin film deposition process. The strengthening treatment is performed using the plasma. After that, during the process of placing the substrate on the electrostatic chuck, it is performed in a state where the application of the electrostatic chuck voltage and the RF power supply is interrupted. <Comparative Example> First, a nitride film and an oxide film specimen are respectively attached to the lower surface of the showerhead provided inside the process chamber. Secondly, the thin film deposition process is performed in the same method as in the embodiment. During the process of transporting the substrate out and placing it, the DC power supply and the RF power supply are not applied, and the thin film deposition process is continuously performed. <Experimental Example> (1) Refractive index evaluation In order to evaluate the influence on the film quality strengthening when performing the thin film deposition process using the methods of the embodiment and the comparative example, the influence on the refractive index of the thin film of the specimen was evaluated, and the results are shown in FIG. 5. FIG. 5 is the result of evaluating the change in the refractive index (reflective index, R.I) of the specimen attached inside the chamber after depositing the silicon nitride film and the silicon oxide film several times respectively using the methods of the embodiment and the comparative example. As shown in FIG. 5, compared with the case of the comparative example, when the thin film is formed using the method of the embodiment, there is a tendency for the refractive index to increase. This increase in the refractive index indicates an increase in the thickness of the film quality, and it can be confirmed that the density of the deposited thin film such as the oxide film or the nitride film formed on the gas injection part side will increase. (2) Evaluation of the generation of particles In order to evaluate the influence on the generation of particles when performing the thin film deposition process using the methods of the embodiment and the comparative example, the results are shown in FIG. 6. FIG. 6 is the evaluation result of the number of particles generated by alternately depositing the silicon nitride film and the silicon oxide film on the substrate 100 times each time (thickness standard: <4 μm) and depositing three times in total (thickness standard: >10 μm) using the methods of the embodiment and the comparative example. As shown in FIG. 6, when forming a thin film by the method of the comparative example, as the composite film deposition process is repeatedly executed, the number of generated particles shows a tendency to increase sharply. However, when forming a thin film by the method of the embodiment, a certain number of particles are formed, and it is confirmed that the direct current (DC) plasma treatment that forms plasma by supplying a DC power source to the electrostatic chuck and supplying a purge gas can improve the particles. (3) Evaluation of the yield per equipment (unit per equipment hour, UPEH) The influence on the yield per equipment when performing the thin film deposition process by the methods of the embodiment and the comparative example was evaluated. Among them, it was evaluated assuming that the maximum DC plasma treatment time was 60 seconds for 2 times. As a result, due to the increase in the treatment time caused by the DC plasma treatment of the embodiment, the yield per equipment will decrease by 0.6 sheets. In the process of continuously depositing thin films, the comparative example was 20 sheets in total, while the embodiment was 24 sheets in total, having an additional thin film deposition effect of 4 sheets in total, and the yield per equipment can be greatly improved. From the above results, when using the thin film forming method of the embodiment, in the purge process of supplying the purge gas, in the process of DC plasma treatment that forms plasma by supplying a DC power source to the electrostatic chuck and supplying the purge gas, the density of the deposited thin film can be increased, the generation of particles in the deposited thin film can be prevented, and the yield per equipment of the substrate processing device can be greatly improved. In particular, the thin film forming method of the embodiment can be applied not only to the mold stacking process, but also to the bulk film deposition process of continuously depositing the same thin film, the composite film deposition process of alternately depositing a plurality of thin films with different compositions, and the process of filling a high aspect ratio space with a composite film. As the number of stacked layers increases, a thin film with high utilization rate and high quality can be formed. 110: Process chamber 112: Processing space 120: Electrostatic chuck 125: Electrostatic electrode 127: Heater 129: Bias electrode 130: Gas injection part 140: Electrostatic power supply part 142: DC power supply 145: DC filter 150: Plasma power supply part 152: First RF power supply 154: Second RF power supply 156: Impedance matching part 160: Control part S: Substrate S10 - S40: Steps FIG. 1 is a timing chart showing an example of a conventional thin film forming method; FIG. 2 is a timing chart showing a thin film forming method according to an embodiment of the present invention; FIG. 3 is a flowchart showing a thin film forming method according to an embodiment of the present invention; FIG. 4 is a schematic diagram showing a substrate processing apparatus according to an embodiment of the present invention; FIG. 5 is a result of evaluating the change in refractive index (reflective index, R.I) of a specimen attached to the inside of a chamber after depositing a silicon nitride film and a silicon oxide film several times respectively using the methods of the embodiment and the comparative example of the present invention; and FIG. 6 is an evaluation result of the number of particles generated by alternately depositing a silicon nitride film and a silicon oxide film on a substrate 100 times each time (thickness standard: <4 μm) and depositing three times in total (thickness standard: >10 μm) using the methods of the embodiment and the comparative example of the present invention.
Claims
1. A method for forming a thin film, utilizing: The process chamber has a processing space for substrate processing; An electrostatic chuck is disposed inside the processing space and the substrate is placed thereon; A gas injection unit for injecting gas onto the substrate; an electrostatic power supply unit for applying DC power to cause the electrostatic chuck to clamp the substrate. And a substrate processing apparatus, wherein an RF power supply unit applies RF power to form plasma in the process chamber; The invention is characterized by the following steps: a placement step, in which the substrate is placed on the electrostatic chuck; a deposition step, in which a first DC power supply is applied to clamp the substrate, a process gas is supplied and a first RF power supply is applied to form a first plasma, thereby depositing a thin film on the substrate; and a transport step, in which the substrate with the deposited thin film is transported to the outside of the process chamber. The process includes a DC plasma treatment step, in which a second DC power supply is applied, a purge gas is supplied, and a second RF power supply is applied to form plasma, thereby performing a strengthening treatment on the deposited film formed inside the process chamber and on the surface of the gas jet section.
2. The thin film forming method according to claim 1, wherein, The step of depositing a thin film on the substrate is a process of depositing a thin film with a thickness of at least 10 to 20 mm.
3. The thin film forming method according to claim 1, wherein, In the step of depositing a thin film on the substrate, a composite film is formed on the substrate by alternately depositing a first thin film and a second thin film on the substrate at least once.
4. The thin film forming method according to claim 3, wherein, The first film and the second film are any one of silicon oxide film (SiO2 layer), silicon nitride film (SiN layer), silicon oxynitride film (SiON layer), and silicon carbon nitride film (SiOCN), and the composition of the first film and the second film is different.
5. The thin film forming method according to claim 3, wherein, The first film is a silicon oxide film (SiO2 layer), while the second film is a silicon nitride film (SiN layer).
6. The thin film forming method according to claim 1, wherein, In the step of depositing a thin film on the substrate, at least one of an HF power source and a VHF power source is supplied to form a plasma, thereby depositing the thin film.
7. The thin film forming method according to claim 1, wherein, The voltage of the second DC power supply is higher than the voltage of the first DC power supply.
8. The thin film forming method according to claim 1, wherein, The second DC power supply is a positive voltage of 100 to 1000 V.
9. The thin film forming method according to claim 1, wherein, The power of the second RF power supply is lower than that of the first RF power supply.
10. The thin film forming method according to claim 1, wherein, The power of the second RF power supply is 50 to 500W.
11. The thin film forming method according to claim 1, wherein, In the strengthening process, the DC plasma treatment step is performed for 5 to 180 seconds.
12. The thin film forming method according to claim 1, wherein, The strengthening process further includes a stabilization step, wherein after the deposited film is strengthened, the application of the second DC power supply and the second RF power supply is interrupted.
13. The thin film forming method according to claim 1, wherein, In the strengthening process, a composite film is formed by alternately depositing a plurality of double films on the upper part of the substrate, with the first film and the second film being deposited at least once.
14. The thin film forming method according to claim 1, wherein, A deposition pattern is formed on the upper part of the substrate, the deposition pattern including a plurality of pattern blocks and high aspect ratio spaces formed between the pattern blocks, and wherein, in the step of depositing a thin film on the substrate, a first thin film and a second thin film are alternately deposited at least once in such a way as to alternately deposit a plurality of double thin films on the upper part of the substrate to form a composite film in the high aspect ratio space.
15. A substrate processing apparatus, comprising: The process chamber has a processing space for substrate processing; An electrostatic chuck is disposed inside the processing space and the substrate is placed thereon; The system includes: a gas jetting unit for jetting gas onto the substrate; an electrostatic power supply unit for applying DC power to clamp the substrate with the electrostatic chuck; a plasma power supply unit for applying RF power to form plasma in the process chamber; and a control unit for controlling the operation of the electrostatic chuck, the gas jetting unit, the electrostatic power supply unit, and the plasma power supply unit. The control unit's operation includes: applying a first DC power to the electrostatic chuck; applying a first RF power to the electrostatic chuck or the gas jetting unit and then interrupting the application of the first DC power and the first RF power after a deposition process of depositing a thin film on the substrate in the processing space; transporting the substrate with the deposited film to the outside of the processing space and then supplying purge gas to the processing space; applying a second DC power and a second RF power to form plasma; and DC plasma treatment to strengthen the deposited film formed inside the process chamber and on the surface of the gas jetting unit.
16. The substrate processing apparatus according to claim 15, wherein, The control unit further includes: after performing the DC plasma process, interrupting the application of the second DC power supply and the second RF power supply; placing the substrate on the electrostatic chuck, applying the first DC power supply and the first RF power supply; and clamping the new substrate for thin film deposition and supplying process gas to form plasma and deposit the thin film.