Substrate processing method and substrate processing system

Abstract

To provide a technology capable of reducing a warp of a substrate caused by stress when an element is formed on a front surface of the substrate without obstructing a subsequent photolithography process.SOLUTION: A substrate processing method includes: preparing a substrate having a front surface on which an element is formed and a rear surface; forming a film on the whole surface of the rear surface of the substrate; and adjusting stress of the film by performing plasma processing locally on part of the film formed on the rear surface of the substrate.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a substrate processing method and a substrate processing system. [Background technology]

[0002] For example, when forming an element made up of multiple stacked layers, such as 3D NAND, on the surface of a substrate, film stress can cause large and complex stresses to be applied to the substrate, which can lead to warping of the substrate after heat treatment in a subsequent process. Patent Document 1 describes a technique that can resolve this problem: a mask is prepared according to the measurement results of the substrate's surface condition, and this mask is used to form a film at a desired position on the back surface of the substrate, thereby compensating for local warpage of the wafer. Furthermore, Patent Document 2 describes a film formation apparatus that can form a film at a desired position on the back surface of a substrate to reduce substrate warpage, etc. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-77751 [Patent Document 2] Japanese Patent Publication No. 2020-158856 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a technique that can reduce warpage of a substrate caused by stress when elements are formed on the surface of the substrate without interfering with subsequent photolithography processes. [Means for solving the problem]

[0005] A substrate processing method according to one aspect of the present disclosure includes preparing a substrate having a front surface and a back surface and having elements formed on the front surface, forming a film over the entire back surface of the substrate, and locally plasma processing a portion of the film formed on the back surface of the substrate. [Effects of the Invention]

[0006] According to the present disclosure, a technique is provided that can reduce warpage of a substrate caused by stress when elements are formed on the surface of the substrate without interfering with subsequent photolithography processes. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a flowchart illustrating a substrate processing method according to an embodiment. [Figure 2] 1 is a schematic configuration diagram illustrating an example of a substrate processing system for performing a substrate processing method according to an embodiment. [Figure 3] 1 is a cross-sectional view showing an example of a film forming apparatus in a substrate processing system. [Figure 4] 4 is a plan view schematically showing a microwave supply unit in the plasma source of the film forming apparatus of FIG. 3. FIG. [Figure 5] 4 is a cross-sectional view showing an example of a microwave radiation mechanism of the film forming apparatus of FIG. 3. [Figure 6] 1 is a cross-sectional view showing an example of a plasma processing apparatus in a substrate processing system. [Figure 7] 7 is a diagram for explaining the relative movement between the microwave radiation mechanism and the substrate in the plasma processing apparatus of FIG. 6. FIG. [Figure 8] 7 is a diagram showing an example of forming a modified portion by plasma processing after the microwave radiation mechanism is positioned by the movement mechanism in the plasma processing apparatus of FIG. 6 and then the substrate is rotated. FIG. [Figure 9] FIG. 7 is a diagram showing an example in which a modified portion is formed at a predetermined position in the XY coordinate system and in a predetermined shape by combining movement of the microwave radiation mechanism by the movement mechanism and rotation of the substrate in the plasma processing apparatus of FIG. 6. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, the embodiments will be specifically described with reference to the accompanying drawings. FIG. 1 is a flowchart showing a substrate processing method according to an embodiment.

[0009] In this embodiment, first, a substrate having a front surface and a back surface and having an element formed on the front surface is prepared (step ST1). Next, a film is formed on the entire back surface of the substrate (step ST2). Next, a portion of the film formed on the back surface of the substrate is locally plasma-treated (step ST3).

[0010] In step ST1, the substrate is not particularly limited, but a typical example is a semiconductor substrate (wafer), in which case the element formed is a semiconductor element (semiconductor device). The element formed on the surface of the substrate is formed by repeating a film formation process and an etching process to stack multiple films. Since the element formed in this manner has a complex structure, stress from the films is applied to the substrate, and warping of the substrate may occur due to heat treatment in a subsequent process. In particular, when an element formed on the substrate is formed by stacking, for example, 100 or more layers of films, such as 3D NAND, the stress becomes large and complex, and the warping of the substrate also becomes large and complex.

[0011] In step ST2, the stress is adjusted by forming a film on the entire back surface of the substrate. In this case, "the entire back surface" does not have to be the entire surface; for example, it is acceptable if the film is not formed in a very narrow area at the edge of the substrate. In the as-depo state where the film is formed on the entire back surface of the substrate, the film stress may be tensile (tensile stress).

[0012] The film formed on the rear surface of the substrate is not particularly limited, but examples thereof include a silicon nitride (SiN) film. The film formation method is also not particularly limited, but plasma CVD, particularly microwave plasma CVD, is preferably used. When a SiN film is formed as the rear surface film, the film stress in the as-deposited state is tensile. In addition to a SiN film, a SiO film or a Si film can also be used as the film formed on the rear surface.

[0013] For example, when the film to be formed on the rear surface of the substrate is a SiN film, plasma CVD can be suitably used. When forming a SiN film by plasma CVD, a Si-containing gas and a nitrogen-containing gas are used, and a microwave plasma source, for example, can be used as the plasma source. The film thickness to be formed on the rear surface of the substrate can be, for example, in the range of 10 to 500 nm.

[0014] The localized plasma treatment in step ST3 has the function of modifying the film formed on the backside of the substrate and adjusting the film stress. For example, if the film stress when a film is formed on the entire backside is in the tensile direction (tensile direction), the plasma treatment can change the film stress to the compressive side. The amount of change in film stress due to the plasma treatment can be adjusted by the type of processing gas used in the plasma treatment and / or the power supplied for plasma generation. In addition, the amount of change in film stress can also be adjusted by other factors such as gas flow rate.

[0015] In step ST3, the position where local plasma processing is performed on the backside of the substrate is determined based on the film stress on the front side of the substrate. Elements with complex structures are formed on the front side of the substrate by repeating film formation and etching processes, and a complex stress distribution exists on the front side of the substrate. Therefore, the stress (stress distribution) on the front side of the substrate is measured in advance, and the position where local plasma processing is performed is determined so that the film stress distribution on the backside of the substrate compensates for the stress distribution on the front side. The processing gas used for plasma processing can be a gas that can modify the film formed on the backside of the substrate to adjust the stress, such as H2, Ar, NH3, N2, O2, NO, or NO. These can be used alone or in combination.

[0016] For example, when the film formed on the backside of the substrate is a SiN film, the film stress as a whole is tensile. However, by modifying the SiN film using, for example, H2 / Ar plasma or Ar plasma, the stress in the modified portion becomes compressive, thereby adjusting the stress on the backside of the substrate. Furthermore, by modifying using NH3 / Ar plasma, the stress in the modified portion becomes more tensile, thereby adjusting the stress on the backside of the substrate. When the film formed on the backside of the substrate is a SiO film, the stress on the backside of the substrate is adjusted by modifying using H2, Ar, O2, NO, NO, or a combination thereof. When the film formed on the backside of the substrate is a Si film, the stress on the backside of the substrate is adjusted by modifying using H2, Ar, NH3, N2, O2, NO, NO, or a combination thereof.

[0017] Such localized plasma processing can be performed using an apparatus having a plasma source capable of localized plasma generation and a movement mechanism that causes relative movement between the substrate and the plasma source. By using the movement mechanism to cause relative movement between the substrate and the plasma source, the position where the plasma processing of the film on the backside of the substrate is performed can be adjusted. For example, the plasma source can be one that generates microwave plasma by locally irradiating microwaves. For example, the movement mechanism can be one that rotates the plasma source in a plane parallel to the substrate and rotates the substrate to cause relative movement.

[0018] As described above, conventionally, a technique for dealing with substrate warpage caused by increased film stress due to the increased stacking of elements formed on the surface of a substrate has been used in which a film is locally formed at a desired position on the back surface of the substrate in accordance with the stress on the surface of the substrate, thereby compensating for the local warpage of the substrate (see Patent Documents 1 and 2 above).

[0019] However, a substrate having a film locally formed on the rear surface is likely to be undesirable in the subsequent photolithography process due to accuracy considerations and the like.

[0020] Therefore, in this embodiment, a film is formed on the entire back surface of the substrate, and a portion of the film formed on the back surface is locally plasma-treated. As a result, since a film is formed on the entire back surface of the substrate, warping of the substrate due to film stress can be reduced without interfering with the subsequent photolithography process.

[0021] <Substrate processing system> Next, a substrate processing system for carrying out the substrate processing method of one embodiment will be described. Fig. 2 is a schematic diagram showing an example of the substrate processing system for carrying out the substrate processing method of one embodiment.

[0022] The processing system 100 includes a film forming apparatus 200 for forming a film on the entire rear surface of a substrate, a plasma processing apparatus 300 for locally performing plasma processing on a part of the film formed on the rear surface of the substrate, and a control unit 400.

[0023] First, a description will be given of the film formation apparatus 200. Fig. 3 is a cross-sectional view showing an example of the film formation apparatus 200, Fig. 4 is a plan view schematically showing a microwave supply unit in a plasma source of the film formation apparatus 200, and Fig. 5 is a cross-sectional view showing a microwave radiation mechanism of the film formation apparatus 200.

[0024] The film forming apparatus 200 is configured as a plasma CVD apparatus that forms a film using microwave plasma, and the film formed is, for example, a SiN film.

[0025] The film forming apparatus 200 has a substantially cylindrical, grounded chamber 1 made of a metal material such as aluminum or stainless steel, which is configured to be airtight, and a plasma source 2 for generating microwave plasma by radiating microwaves into the chamber 1. An opening 1a is formed in the top of the chamber 1, and the plasma source 2 is provided so as to face the interior of the chamber 1 through this opening 1a.

[0026] A mounting table 11, which is a support member for horizontally supporting a substrate W, is provided in the chamber 1 and is supported by a cylindrical support member 12 that stands in the center of the bottom of the chamber 1 via an insulating member 12a. The substrate W is supported on the mounting table 11 with its backside facing up. The mounting table 11 and the support member 12 can be made of, for example, aluminum with an anodized surface.

[0027] Although not shown, the mounting table 11 is also provided with a heater for heating the substrate W, a gas flow path for supplying a gas for heat transfer to the backside of the substrate W, and lifting pins for lifting and lowering the substrate W to transport it. The mounting table 11 may also be provided with an electrostatic chuck for electrostatically attracting the substrate W. A high-frequency bias power supply 14 is electrically connected to the mounting table 11 via a matching box 13. When high-frequency power is supplied from the high-frequency bias power supply 14 to the mounting table 11, ions in the plasma are attracted toward the wafer W. The high-frequency bias power supply 14 is not essential.

[0028] An exhaust pipe 15 is connected to the bottom of the chamber 1, and an exhaust device 16 including a vacuum pump is connected to this exhaust pipe 15. By operating this exhaust device 16, gas inside the chamber 1 is exhausted, making it possible to quickly reduce the pressure inside the chamber 1 to a predetermined vacuum level. In addition, a sidewall of the chamber 1 is provided with a load / unload port 17 for loading and unloading the substrate W, and a gate valve 18 for opening and closing this load / unload port 17.

[0029] A ring-shaped gas introduction member 26 is provided at the top of the chamber 1 along the chamber wall, and multiple gas outlet holes are provided on the inner periphery of this gas introduction member 26. A gas supply source 27 for supplying a process gas is connected to this gas introduction member 26 via piping 28. When forming a SiN film as the film, a Si-containing gas and a nitrogen-containing gas can be used as the process gas. Alternatively, a rare gas such as Ar gas can be supplied. Examples of the Si-containing gas include silane-based compound gases such as monosilane (SiH) gas, disilane (SiH) gas, and trimethylsilane (SiH(CH)). Examples of the nitrogen-containing gas include ammonia (NH) gas and nitrogen (N). The process gas can also be introduced from other locations, such as the ceiling wall of the chamber 1.

[0030] The gas introduced into the chamber 1 from the gas introduction member 26 is excited into plasma by microwaves introduced into the chamber 1 from the plasma source 2, and a film is formed on the entire rear surface of the substrate W by plasma CVD.

[0031] The plasma source 2 is used to generate plasma by radiating microwaves into the chamber 1, and has a circular plate-like member 110 supported by a support ring 29 provided on the top of the chamber 1, with the space between the support ring 29 and the plate-like member 110 sealed airtight. The plate-like member 110 also functions as the ceiling wall of the chamber 1.

[0032] The plasma source 2 generates microwaves and radiates the generated microwaves into the chamber 1 to generate plasma, and includes a microwave output unit 30 and a microwave supply unit 40.

[0033] The microwave output unit 30 has a microwave power source, a microwave oscillator that oscillates microwaves, an amplifier that amplifies the oscillated microwaves, and a distributor that distributes the amplified microwaves into multiple parts, and then distributes the microwaves into multiple parts and outputs them.

[0034] The microwave supply unit 40 has a plurality of amplifier units 42 that mainly amplify the microwaves distributed by the distributor of the microwave output unit 30, and a microwave radiation mechanism 41 connected to each of the plurality of amplifier units 42.

[0035] 4, for example, a total of seven microwave radiation mechanisms 41 are arranged on the plate-like member 110, six arranged circumferentially and one at the center. Note that the number of microwave radiation mechanisms 41 is not limited to seven.

[0036] The plate-like member 110 functions as a vacuum seal and a microwave-transmitting plate, and has a metal frame 110a and a microwave-transmitting window 110b made of a dielectric material such as quartz that is fitted into the frame 110a. The microwave-transmitting window 110b is provided so as to correspond to the portion where the microwave radiation mechanism 41 is disposed.

[0037] 5, the microwave radiation mechanism 41 has a coaxial waveguide 44 that transmits microwaves, and an antenna part 43 that radiates the microwaves transmitted through the waveguide 44 into the chamber 1. The microwaves radiated from the microwave radiation mechanism 41 into the chamber 1 are combined in the space within the chamber 1, and microwave plasma is formed within the chamber 1.

[0038] The waveguide 44 is configured by a cylindrical outer conductor 52 and a rod-shaped inner conductor 53 provided at the center of the outer conductor 52, which are arranged coaxially, and the antenna part 43 is provided at the tip of the waveguide 44. The inner conductor 53 of the waveguide 44 is the power supply side, and the outer conductor 52 is the ground side. The upper ends of the outer conductor 52 and the inner conductor 53 form reflectors 58.

[0039] A power feeding mechanism 54 that feeds microwaves (electromagnetic waves) is provided on the base end side of the waveguide 44. The power feeding mechanism 54 has a microwave power introduction port 55 that is provided on the side surface of the waveguide 44 (outer conductor 52) and that introduces microwave power. A coaxial line 56 consisting of an inner conductor 56a and an outer conductor 56b is connected to the microwave power introduction port 55 as a power feeding line for supplying microwaves amplified from the amplifier section 42. A power feeding antenna 90 that extends horizontally toward the inside of the outer conductor 52 is connected to the tip of the inner conductor 56a of the coaxial line 56.

[0040] When the power feeding antenna 90 radiates microwaves, microwave power is fed to the space between the outer conductor 52 and the inner conductor 53. Then, the microwave power supplied to the power feeding mechanism 54 propagates toward the antenna unit 43.

[0041] A tuner 60 is provided in the waveguide 44. The tuner 60 has two slugs 61a, 61b provided between the outer conductor 52 and the inner conductor 53, and an actuator 70 for driving the slugs provided outside (on the upper side of) the reflector 58. By independently driving the two slugs 61a, 61b up and down using the actuator 70, the impedance of the load (plasma) in the chamber 1 is matched to the characteristic impedance of the microwave power source in the microwave output unit 30.

[0042] The positions of the slugs 61a and 61b are controlled by a slug controller 71. For example, the slug controller 71 sends a control signal to a motor constituting the actuator 70 based on the impedance value of the input terminal detected by an impedance detector (not shown) and the position information of the slugs 61a and 61b detected by an encoder or the like. This controls the positions of the slugs 61a and 61b and adjusts the impedance. The slug controller 71 performs impedance matching so that the termination becomes, for example, 50 Ω.

[0043] The antenna unit 43 has a planar slot antenna 81 and a slow-wave material 82 provided on the back (top) surface of the planar slot antenna 81. A cylindrical member 82a made of a conductor connected to the inner conductor 53 penetrates the center of the slow-wave material 82, and the cylindrical member 82a is connected to the planar slot antenna 81. The slow-wave material 82 and the planar slot antenna 81 are disk-shaped with a larger diameter than the outer conductor 52. The lower end of the outer conductor 52 extends to the planar slot antenna 81, and the periphery of the slow-wave material 82 is covered with the outer conductor 52.

[0044] The planar slot antenna 81 has slots 81a that radiate microwaves. The number, arrangement, and shape of the slots 81a are appropriately set so as to efficiently radiate microwaves. A dielectric may be inserted into the slots 81a.

[0045] The slow-wave material 82 has a dielectric constant greater than that of a vacuum, and is made of, for example, quartz, ceramics, fluorine-based resins such as polytetrafluoroethylene, or polyimide-based resins. The slow-wave material 82 has the function of shortening the wavelength of the microwave compared to that in a vacuum, thereby making the antenna smaller. The slow-wave material 82 can adjust the phase of the microwave by its thickness, and its thickness is adjusted so that the planar slot antenna 81 becomes a "bell" of the standing wave. This minimizes reflection and maximizes the radiant energy of the planar slot antenna 81.

[0046] The microwave-transmitting window 110b described above is disposed further toward the tip of the planar slot antenna 81. The microwaves amplified by the amplifier unit 42 pass between the peripheral walls of the inner conductor 53 and the outer conductor 52, and are transmitted from the planar slot antenna 81 through the microwave-transmitting window 110b, and are then radiated into the space within the chamber 1. The microwave-transmitting window 110b can be made of the same dielectric material as the slow-wave material 82.

[0047] Next, a description will be given of the plasma processing apparatus 300. Fig. 6 is a cross-sectional view showing an example of the plasma processing apparatus 300.

[0048] The plasma processing apparatus 300 includes an airtight, substantially cylindrical, grounded chamber 201 made of a metal material such as aluminum or stainless steel, a plasma source 202 provided above the chamber 201, and a relative movement mechanism 204 that causes relative movement between the plasma source 202 and the substrate W.

[0049] A support ring 229 is provided on the upper part of the chamber 201, and an opening 201a is formed in the support ring 229. A top plate 203 made of a dielectric material is provided on the support ring 229 so as to cover the opening 201a. The space between the support ring 229 and the top plate 203 is airtightly sealed.

[0050] A mounting table 211, which is a support member for horizontally supporting a substrate W, is provided within the chamber 201 and is supported by a cylindrical support member 212 that is erected in the center of the bottom of the chamber 201. The substrate W is supported on the mounting table 211 with its backside facing up. Examples of materials that can be used to form the mounting table 211 and the support member 212 include aluminum with anodized surfaces. The support member 212 extends below the chamber 201 through a through-hole formed in the bottom wall of the chamber 201, and its lower end is connected to a rotation mechanism 213. The rotation mechanism 213 rotates the mounting table 211 via the support member 212, so that the substrate W on the mounting table 211 rotates together with the mounting table 211. Although not shown, the mounting table 211 can be raised and lowered by a lifting mechanism. Although not shown, the mounting table 211 is provided with a temperature control mechanism for controlling the temperature of the substrate W, a gas flow path for supplying a gas for heat transfer to the backside of the substrate W, and lifting pins for raising and lowering the substrate W to transport the substrate W. The mounting table 211 may be provided with an electrostatic chuck for electrostatically attracting the substrate W. A sealing mechanism 214 such as a fluid seal is provided between the support member 212 and the bottom wall of the chamber 201.

[0051] An exhaust pipe 215 is connected to the bottom of the chamber 201, and an exhaust device 216 including a vacuum pump is connected to the exhaust pipe 215. By operating the exhaust device 216, gas inside the chamber 201 is exhausted, making it possible to quickly reduce the pressure inside the chamber 201 to a predetermined vacuum level. In addition, a sidewall of the chamber 201 is provided with a loading / unloading port for loading and unloading the substrate W, and a gate valve for opening and closing the loading / unloading port (neither is shown).

[0052] A ring-shaped gas introduction member 226 is provided at the top of the chamber 201 along the chamber wall, and multiple gas discharge holes are formed on the inner periphery of this gas introduction member 226. A gas supply source 227 that supplies a processing gas for plasma processing is connected to this gas introduction member 226 via piping 228. As the processing gas for plasma processing, a gas that can modify the film formed on the backside of the substrate W and adjust stress, such as H2, Ar, NH3, N2, O2, NO, or NO, as described above, can be used. These gases may be used alone or in combination. For example, if the film formed on the substrate W is a SiN film, the film can be modified using H2 / Ar plasma or Ar plasma, as described above. However, the gas is not limited to these.

[0053] The plasma source 202 is for generating local plasma by radiating microwaves into the chamber 201. The plasma source 202 includes a microwave output unit 230, a microwave radiation mechanism 241, and an amplifier unit 242.

[0054] The microwave output unit 230 includes a microwave power supply, a microwave oscillator that generates microwaves, and an amplifier that amplifies the generated microwaves. The amplifier unit 242 mainly functions to amplify the microwaves from the microwave output unit 230. The microwave radiation mechanism 241 is movably provided on the dielectric top plate 203 and is configured similarly to the microwave radiation mechanism 41 of the film forming apparatus 200 shown in FIG. 5 described above. That is, the microwave radiation mechanism 241 is connected to the amplifier unit 242 and includes a transmission path that transmits microwaves from the amplifier unit 242, a tuner for impedance matching, and an antenna unit that radiates microwaves. The microwaves radiated from the microwave radiation mechanism 241 are supplied to the chamber 201 through the top plate 203.

[0055] The relative movement mechanism 204 is composed of a movement mechanism 250 that moves the microwave radiation mechanism 241 and a rotation mechanism 213 that rotates the substrate W via the mounting table 211, and these are used to adjust the position where plasma processing of the film on the substrate W is performed.

[0056] The moving mechanism 250 rotates the microwave radiation mechanism 241 on the top plate 203, and includes a holding member 251 that holds the microwave radiation mechanism 241, and a rotation mechanism 252 that rotates the holding member 251. The holding member 251 has a vertical portion 251a that extends vertically downward from an upper position on the top plate 203, and a horizontal portion 251b that extends horizontally from the lower end of the vertical portion 251a, and has an L-shaped cross section. The microwave radiation mechanism 241 is held by the horizontal portion 251b. The rotation mechanism 252 is located above the vertical portion 251a, and its rotation axis is at the center of the vertical portion 251a. The vertical portion 251a is rotated by the rotation mechanism 252, and as the microwave radiation mechanism 241 is rotated on the top plate 203 via the horizontal portion 251b, the microwave radiation mechanism 241 held by the horizontal portion 251b. The microwave radiation mechanism 241 can be configured to slide on the top plate 203 when moved by the moving mechanism 250 .

[0057] The relative movement mechanism 204 can position the microwave radiation mechanism 241 at any position on the film formed on the back surface of the substrate W by combining the rotation of the microwave radiation mechanism 241 above the substrate W and the rotation of the substrate W by the rotation mechanism 213.

[0058] Next, the control unit 400 will be described. The control unit 400 controls the operation and processing of each component of the film forming apparatus 200 and the plasma processing apparatus 300 that make up the substrate processing system 100. The control unit 400 is typically a computer and includes a main control unit, an input device, an output device, a display device, and a storage device. The main control unit has a CPU (Central Processing Unit), RAM, and ROM. The storage device has a computer-readable storage medium such as a hard disk, and is configured to record and read information necessary for control. In the control unit 400, the CPU uses the RAM as a working area to execute programs such as processing recipes stored in the ROM or the storage medium of the storage device, thereby controlling the substrate processing system 100. The control unit 400 also has the function of determining the position at which plasma processing of a film formed on the back surface of the substrate W is performed, depending on the film stress on the front surface side of the substrate W.

[0059] The transfer device that transfers the substrate W from the film forming device 200 to the plasma processing device 300 may be an in-situ transfer device using a vacuum transfer chamber, or may be a transfer device that transfers in the air atmosphere.

[0060] Next, a description will be given of the processing operation of the substrate processing system 100 configured as above. The following processing operation is performed under the control of the control unit 400.

[0061] First, a substrate W is loaded into chamber 1 of film formation apparatus 200 and placed on mounting table 11, and gate valve 18 is closed. At this time, mounting table 11 is heated by a heater (not shown), and the temperature of substrate W on mounting table 11 is controlled. When a SiN film is to be formed as a film, the temperature of substrate W is set to, for example, 500 to 650°C. Then, chamber 1 is evacuated using exhaust device 16 to achieve a desired vacuum state. Then, a process gas is introduced into chamber 1 from gas supply source 27 via piping 28 and gas introduction member 26, and the pressure in chamber 1 is controlled to perform a film formation process by plasma CVD. When a SiN film is to be formed as a film, a Si-containing gas and an N-containing gas are used as process gases, and a rare gas such as Ar gas is also used as needed. The pressure in chamber 1 can be set to, for example, 266 Pa or less.

[0062] To generate plasma, microwaves are output from the microwave output unit 30 of the plasma source 2 while a process gas is introduced into the chamber 1. The microwaves distributed and output from the microwave output unit 30 are amplified by the amplifier unit 42 of the microwave supply unit 40, fed to the waveguide 44 of the microwave radiation mechanism 41, and radiated into the chamber 1 via the slow-wave material 82 of the antenna unit 43, the slot 81a of the planar slot antenna 81, and the microwave-transparent window 110b. By moving the slugs 61a and 61b of the tuner 60, impedance is automatically matched, allowing the microwaves to be supplied with virtually no power reflection. The radiated microwaves propagate along the surface of the microwave-transparent window 110b. The electric field of the microwaves excites the gas introduced into the chamber 1, generating plasma in the plasma generation space within the chamber 1. This results in the formation of a SiN film, for example, on the entire backside of the substrate W by plasma-enhanced CVD.

[0063] Process adjustment parameters during film formation include the gas flow rate, gas flow rate ratio, pressure, and microwave output power radiated from each microwave emission mechanism 41. By individually adjusting the microwave output power of each microwave emission mechanism 41, the film formation distribution can be controlled.

[0064] Microwave plasma allows the electron temperature to be controlled low, so film formation can be performed without damaging the film to be formed or the elements on the substrate W. Furthermore, because microwave plasma is a high-density plasma, the density of the resulting film can be increased, making it suitable as a film for stress adjustment.

[0065] The substrate W having the film formed on the entire rear surface thereof as described above is carried into the chamber 201 of the plasma processing apparatus 300 and placed on the mounting table 211. Then, the chamber 201 is evacuated by the exhaust device 216 to create a desired vacuum state, and then a processing gas is introduced into the chamber 201 from the gas supply source 227 via the piping 228 and the gas introduction member 226, and the pressure inside the chamber 201 is controlled to perform local plasma processing on the rear surface of the substrate W.

[0066] The localized plasma processing is performed by rotating the substrate W using the rotation mechanism 213 and rotating the microwave radiation mechanism 241 using the movement mechanism 250 while introducing a processing gas into the chamber 201, and emitting microwaves to a desired position on the substrate W. That is, the microwave radiation mechanism 241, which is a part of the plasma source 202, and the substrate W are moved relative to each other, and the microwaves output from the microwave output unit 230 are radiated from the microwave radiation mechanism 241 to a desired position on the substrate W, thereby generating plasma.

[0067] In this way, any position on the film formed on the rear surface of the substrate W can be modified by plasma processing, and the stress of the modified portion can be adjusted. In this case, the degree of modification by plasma processing can be adjusted by the type of plasma generating gas, flow rate, plasma power, etc. In addition, the position on the rear surface of the substrate W where local plasma processing is performed is determined depending on the stress on the front surface side of the substrate W.

[0068] 7, the vertical part 251a is rotated by the rotation mechanism 252 of the movement mechanism 250, and the microwave radiation mechanism 241 is turned to determine the position of the microwave radiation mechanism 241, and then the substrate W is rotated. This allows plasma processing to be performed at any position on the substrate W.

[0069] For example, in the example of Fig. 8(a), the microwave radiation mechanism 241 is positioned corresponding to the outermost periphery of the substrate W, and then the substrate W is rotated, thereby performing a ring-shaped plasma treatment on the outermost periphery of the film on the rear surface of the substrate, forming a modified region 260. In the example of Fig. 8(b), the microwave radiation mechanism 241 is positioned corresponding to the middle of the substrate W, and then the substrate W is rotated, thereby performing a ring-shaped plasma treatment on the middle portion of the film on the rear surface of the substrate, forming a modified region 260. In the example of Fig. 8(c), the microwave radiation mechanism 241 is positioned corresponding to the center of the substrate W, and then the substrate is rotated, thereby forming a modified region 260 on the center of the film on the rear surface of the substrate.

[0070] Furthermore, by combining the movement of the microwave radiation mechanism 241 by the movement mechanism 250 with the rotation of the substrate W, it is possible to form a modified region 260 in any shape at any position on the XY coordinates. For example, it is possible to form a linear modified region 260 as shown in Fig. 9(a) or a spot-shaped modified region 260 as shown in Fig. 9(b).

[0071] Although the microwaves supplied from the microwave radiation mechanism 241 into the chamber 201 spread somewhat laterally, the electric field strength of the microwaves is highest at the center of the microwave radiation mechanism 241 and is lower outside the microwave radiation mechanism 241. Therefore, the range of modification by plasma can be substantially the microwave irradiation region of the substrate W.

[0072] Microwave plasma can be controlled to have a low electron temperature, so plasma processing can be performed without damaging the elements on the substrate W. Furthermore, microwave plasma is a high-density plasma, so it has a high modification effect.

[0073] <Experimental Example> Next, an experimental example will be described. First, a 25 nm thick SiN film was formed on the back surface of the substrate by microwave plasma CVD using the film formation apparatus shown in Figure 3. The stress of the film in the as-deposited state was 567 MPa tensile.

[0074] This SiN film was subjected to a microwave plasma treatment under the following conditions 1 and 2. ·Condition 1 Processing gas: H2 gas / Ar gas Microwave output: 50W Time: 60sec ·Condition 2 Processing gas: Ar gas Microwave power: 500W Time: 60sec

[0075] The film stress after plasma treatment was 522 MPa under condition 1 and 244 MPa under condition 2, and in both cases the film stress shifted to the compressive side. Specifically, the amount of change to the compressive side was 45 MPa under condition 1 and 323 MPa under condition 2. These results confirmed that the film stress on the backside of the substrate can be adjusted by plasma treatment.

[0076] <Other applications> Although the embodiments have been described above, the disclosed embodiments should be considered to be illustrative and not restrictive in all respects. The above embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims.

[0077] For example, in the above embodiment, an example was shown in which microwave plasma CVD was used to form a film on the entire back surface of the substrate, but this is not limiting, and any film formation method that can adjust the stress of elements on the front surface of the substrate can be used, for example, other plasma CVD, thermal CVD, ALD, PVD, etc. Also, in the above embodiment, a SiN film was used as the film formed on the entire back surface of the substrate, but any film that can adjust the stress of elements on the front surface of the substrate can be used, for example, a SiO film or Si film in addition to a SiN film.

[0078] In the above embodiment, microwave plasma was used to treat the film on the rear surface of the substrate. However, any other plasma treatment capable of adjusting the stress of the film on the rear surface of the substrate can be used, such as capacitively coupled plasma or inductively coupled plasma. Furthermore, while the above embodiment illustrates an example in which local plasma is generated using a microwave radiation mechanism, this is not a limitation. A remote plasma treatment may be used, which generates plasma at a location other than the chamber, and the gas plasma generated by the remote plasma treatment may be emitted. Furthermore, in the above embodiment, the moving mechanism rotates the microwave radiation mechanism constituting the plasma source and rotates the substrate, thereby causing relative movement between the plasma source and the substrate to adjust the position where local plasma treatment is performed. However, this is not a limitation. For example, the position where local plasma treatment is performed on the substrate may be adjusted using an XY table that can move the substrate arbitrarily on the XY coordinates relative to a fixed plasma source. [Explanation of symbols]

[0079] 100; Substrate processing system 200; Film deposition equipment 201;Chamber 202;Plasma source 211;Placement table 213; Rotating mechanism 227;Gas supply source 241: Microwave radiation mechanism 250;Movement mechanism 260; Modification Section 300: Plasma treatment device 400; control section W; substrate

Claims

1. providing a substrate having a front surface and a back surface, the front surface having an element formed thereon; forming a film over the entire back surface of the substrate; adjusting a stress of the film by locally performing a plasma treatment on a portion of the film formed on the back surface of the substrate; A substrate processing method comprising:

2. 2. The substrate processing method according to claim 1, wherein the element is formed by stacking a plurality of films.

3. A substrate processing method as described in claim 1 or claim 2, wherein the position at which the plasma processing of the film formed on the back surface of the substrate is performed is determined according to the film stress on the front surface side of the substrate.

4. 4. The substrate processing method according to claim 1, wherein the plasma processing is performed using an apparatus having a plasma source capable of localized plasma generation and a relative movement mechanism that causes relative movement between the substrate and the plasma source, and the relative movement mechanism adjusts the position at which the plasma processing of the film formed on the back surface of the substrate is performed.

5. A substrate processing method described in any one of claims 1 to 4, wherein the film formed on the back surface of the substrate has a tensile stress.

6. A substrate processing method as described in claim 5, wherein the film formed on the back surface of the substrate is a SiN film.

7. The substrate processing method of claim 5, wherein the film formed on the rear surface of the substrate is a SiO film.

8. A substrate processing method described in any one of claims 5 to 7, wherein forming a film on the entire back surface of the substrate is performed by microwave plasma CVD.

9. 9. The substrate processing method according to claim 5, wherein the plasma processing changes stress of the film formed on the rear surface of the substrate to a compressive stress.

10. 10. The substrate processing method according to claim 9, wherein the amount of change in stress due to the plasma processing is adjusted by the type of processing gas used in the plasma processing and / or the power supplied for generating plasma.

11. a film forming apparatus for forming a film on the entire back surface of a substrate having a front surface and a back surface and having elements formed on the front surface; a plasma processing apparatus that locally performs plasma processing on a portion of the film formed on the rear surface of the substrate to adjust stress of the film; A substrate processing system comprising:

12. 12. The substrate processing system according to claim 11, further comprising a control unit for controlling the film forming apparatus and the plasma processing apparatus, wherein the control unit determines a position where the plasma processing of the film is performed in accordance with a film stress on the front surface side of the substrate.

13. the plasma processing apparatus includes a chamber for performing plasma processing on the substrate, a plasma source capable of local plasma generation, and a relative movement mechanism for generating relative movement between the substrate and the plasma source; 13. The substrate processing system according to claim 11, wherein the relative movement mechanism adjusts a position of the film where the plasma processing is performed.

14. the plasma source has a microwave output unit and a microwave radiation mechanism that is movable on a top plate of the chamber made of a dielectric material and that radiates microwaves output from the microwave output unit into the chamber via the top plate, and is configured to generate microwave plasma in the chamber; 14. The substrate processing system according to claim 13, wherein the relative movement mechanism includes a movement mechanism that rotates the microwave radiation mechanism along the top plate, and a rotation mechanism that rotates the substrate.

15. The substrate processing system according to claim 11 , wherein the film forming device forms a film having a stress in a tensile direction as the film.

16. The substrate processing system according to claim 15 , wherein the film forming device forms a SiN film as the film.

17. The substrate processing system according to claim 15 , wherein the film forming device forms a SiO film as the film.

18. 18. The substrate processing system according to claim 15, wherein the film forming device forms the film by microwave plasma CVD.

19. 19. The substrate processing system according to claim 15, wherein the plasma processing apparatus changes a stress of the film formed by the film forming apparatus to a compressive stress.

20. 20. The substrate processing system according to claim 19, wherein the plasma processing apparatus adjusts the amount of change in stress caused by the plasma processing by adjusting the type of processing gas used in the plasma processing and / or the power supplied for generating plasma.

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