Substrate processing method, substrate processing device, and substrate processing system

Abstract

This substrate processing method includes: preparing a substrate having a first surface on which a device is formed; and forming a silicon-containing film on a second surface on the reverse side of the substrate from the first surface by using a higher silane gas as a film-forming gas at a temperature at which the higher silane gas is liquefied.

Description

SUBSTRATE PROCESSING METHOD, SUBSTRATE PROCESSING APPARATUS, AND SUBSTRATE PROCESSING SYSTEM

[0001] The present disclosure relates to a substrate processing method, a substrate processing apparatus, and a substrate processing system.

[0002] In Patent Document 1, SiO is deposited on the back surface of the substrate by ALD or CVD. ２ The document describes a technique for applying stress to a substrate by forming a dummy film having compressive stress, such as a silicon nitride film or a silicon nitride film.

[0003] Japanese Patent Application Laid-Open No. 2020-150133

[0004] The present disclosure provides a technique capable of generating a large stress on a second surface of a substrate opposite to a first surface on which devices are formed.

[0005] A substrate processing method according to one aspect of the present disclosure includes preparing a substrate having a first surface on which a device is formed, supplying a high-order silane gas as a film-forming gas to a second surface of the substrate opposite the first surface, and forming a silicon-containing film at a temperature at which the high-order silane gas liquefies.

[0006] According to the present disclosure, a technique is provided that can generate a large stress on a second surface of a substrate opposite to a first surface on which devices are formed.

[0007] 5A and 5B are cross-sectional views illustrating the steps of a substrate processing method according to a first embodiment; FIG. 5B is a cross-sectional view illustrating the steps of a substrate processing method according to a first embodiment; FIG. 5C is a cross-sectional view illustrating the base of a sample used in an experiment to confirm stress generated on the second surface of a substrate due to shrinkage of a silicon-containing film formed according to the first embodiment; FIG. 5D is a cross-sectional view illustrating the sample used in an experiment to confirm stress generated on the second surface of a substrate, the sample being formed by forming a silicon-containing film on the base of FIG. 3; FIG. 5E is a diagram illustrating the relationship between annealing temperature and Raman shift when annealing the sample of FIG. 4; FIG. 5F is a cross-sectional view schematically illustrating the stress state on the second surface of a substrate in the initial state (A in FIG. 5A) before forming a silicon-containing film used to determine the relationship of FIG. 5; FIG. 5G is a diagram illustrating the stress on the second surface of a substrate when the annealing temperature is less than 100° C. (B and C in FIG. 5G); FIG. 5H is a diagram illustrating the stress on the second surface of a substrate when the annealing temperature is increased from 100° C. to 200° C. and the Raman shift changes to positive (D in FIG. 5G). 16 is a cross-sectional view illustrating a process of a substrate processing method according to a second embodiment. FIG. 17 is a cross-sectional view illustrating a process of a substrate processing method according to the second embodiment. FIG. 18 is a plan view schematically illustrating an example of a substrate processing system used in carrying out the second embodiment. FIG. 19 is a cross-sectional view illustrating an example of an annealing apparatus used in the substrate processing system of FIG. 12. FIG. 19 is a flowchart illustrating a substrate processing method according to a third embodiment. FIG. 19 is a cross-sectional view illustrating a process of a substrate processing method according to the third embodiment. FIG. 19 is a cross-sectional view illustrating a process of a substrate processing method according to the third embodiment. FIG. 19 is a cross-sectional view illustrating a process of a substrate processing method according to the third embodiment. FIG. 19 is a plan view schematically illustrating an example of a substrate processing system used in carrying out the third embodiment. FIG. 19 is a cross-sectional view schematically illustrating a stress measurement device used in the substrate processing system of FIG.

[0008] Hereinafter, the embodiments will be specifically described with reference to the accompanying drawings.

[0009] First Embodiment [Substrate Processing Method] FIG. 1 is a flowchart showing a substrate processing method according to a first embodiment, and FIGS. 2A to 2B are cross-sectional views of the process steps.

[0010] In this embodiment, first, a substrate 1 having a first surface 2 on which a device is to be formed is prepared (step ST1, FIG. 2A). Next, a high-order silane gas is supplied as a deposition gas to a second surface 3 opposite to the first surface 2 of the substrate 1, and a silicon-containing film 4 is deposited at a temperature at which the high-order silane gas liquefies (step ST2, FIG. 2B).

[0011] In step ST1, the substrate 1 is not particularly limited, but a typical example is a semiconductor substrate (wafer). The first surface 2 of the substrate may or may not actually have a device formed thereon, or may be in the process of forming a device.

[0012] In step ST2, a high-order silane gas is used as a deposition gas, and a silicon-containing film 4 is deposited on the second surface 3 of the substrate 1 at a temperature at which the high-order silane gas is liquefied. The silicon-containing film 4 may be deposited on the entire surface of the second surface 3, or may be deposited on only a part of the second surface 3.

[0013] Higher order silane gas can be liquefied at a practical temperature of about -30°C. By forming a film at a temperature at which the higher order silane gas liquefies, a film is formed in which low-molecular-weight components remain in the film. Therefore, when energy such as heat or light is applied to the resulting silicon-containing film, a large amount of the components in the film vaporize, causing the film to aggregate and shrink significantly. This shrinkage can generate large stress on the second surface 3 of the substrate 1. In other words, a silicon-containing film 4 formed using a higher order silane gas at a temperature at which the higher order silane gas liquefies has a high stress-generating ability for the substrate.

[0014] The process of step ST2 can be performed, for example, by placing the substrate with its second surface facing up on a mounting table in a chamber, maintaining the substrate on the mounting table at a temperature at which the high-order silane gas liquefies, and introducing the high-order silane gas into the chamber and supplying it to the second surface of the substrate in a plasma-excited state. At this time, by passing a coolant through the mounting table, the substrate can be maintained at a temperature at which the high-order silane gas liquefies, e.g., −30° C. The pressure in the chamber at this time may be in the range of 10 Torr or less, e.g., 1 Torr.

[0015] By exciting the higher silane gas with plasma in this way, a film skeleton is formed by vapor phase polymerization even at low temperatures, allowing film formation to proceed. Furthermore, the use of plasma allows for the production of films with high adhesion. The type of plasma is not particularly limited, and various types such as capacitively coupled plasma, inductively coupled plasma, and microwave plasma can be used.

[0016] Higher silanes include disilane (Si ２ H ６ ), trisilane (Si ３ H ８ ), tetrasilane (Si ４ H １０ ) etc., general formula Si ｎ H ２ｎ＋２ (n is a positive integer of 2 or more). ２ H ６ , Si ３ H ８ , Si ４ H １０ The boiling points of these compounds are -14.5°C, 52.8°C, and 108.1°C, respectively, and all of these are monosilane (SiH ４ ), which is sufficiently higher than the boiling point of −112° C., and as mentioned above, can be stably liquefied at a realistic temperature of about −30° C. As for higher order silanes, those with n of 4 or more can obtain a greater shrinking ability.

[0017] The gases used in film formation include high-order silane gas and H ２ A rare gas (e.g., Ar gas) may be used as a gas or a plasma generating gas. A high order silane gas alone or a high order silane gas containing H may be used as a film forming gas.２ When an oxygen-containing gas is added as a film-forming gas, the silicon-containing film is a Si-based film, and becomes a Si film after the vaporized components in the film are vaporized. ２ SiO to be the film ２ By changing the film quality of the silicon-containing film in this way, the shrink characteristics can be changed, and the ability to generate stress on the second surface of the substrate can be adjusted.

[0018] Because silicon-containing film 4 has a large stress-generating ability, it can be thinner than films formed by conventional CVD or ALD to generate a desired stress. The thickness of silicon-containing film 4 can be set appropriately depending on the stress to be generated, and may be in the range of 1 to 10,000 nm.

[0019] In fact, tetrasilane was used as the high-order silane gas used as the film-forming gas, and a substrate was placed on a stage in a chamber at −30°C, at which the high-order silane gas liquefies, and the high-order silane gas was supplied to the substrate in a plasma-excited state to form a silicon-containing film. Then, the ability to generate stress on the second surface of the substrate was investigated.

[0020] Specifically, after forming a silicon-containing film, the substrate on which the silicon-containing film is formed is annealed on a stage at various temperatures, and the desorbed gases are analyzed by thermal desorption spectroscopy (TDS). ２ gas, and SiH ４ , Si ２ H ６ , Si ３ H ８ In addition, after the substrate was annealed at various temperatures, the film structure change was confirmed by Fourier transform infrared spectroscopy (FT-IR). As the annealing temperature increased, the amount of SiH ｘ (SiH, SiH ２ , SiH ３ , (SiH ２ ) ｎFrom these results, it was confirmed that the shrinkage of the silicon-containing film formed according to this embodiment is due to the H ２ It was confirmed that this was caused by the desorption of gas and silane-based gas.

[0021] Next, we confirmed the stress generated on the second surface of the substrate due to shrinkage of the silicon-containing film formed according to this embodiment. Here, as shown in Figure 3, a sample was prepared in which thermal oxide films 203 and 204 were formed to a thickness of 100 nm on both the first surface 201 and the second surface 202 of a Si substrate 200. As shown in Figure 4, a sample was prepared in which a silicon-containing film 205 was formed to a thickness of 50 nm on the thermal oxide film 204 on the second surface 202 side of the Si substrate 200. The thermal oxide film was formed to distinguish the silicon-containing film from the Si substrate, since it is a Si-based film.

[0022] This sample was annealed to determine the stress generated on the second surface 202 of the substrate 200 due to the shrinkage of the silicon-containing film 205. The stress was measured by cross-sectional Raman measurement (Raman spectroscopy). The stress generated on the substrate due to the shrinkage of the silicon-containing film was measured at 520 (cm), which is the peak of Si crystal (crystal not subjected to stress) in the spectrum of Raman scattered light (Raman spectrum). －１ ) can be calculated based on the shift (Raman shift) from the Raman shift (cm －１ ), Σ: stress (MPa), the relationship shown in the following formula (1) holds. Therefore, the stress applied to the second surface of the substrate due to shrinkage of the silicon-containing film can be calculated from this formula (1) based on the Raman shift: ν=−1.93×10 －３ Σ ... (1)

[0023] FIG. 5 shows the relationship between the annealing temperature and the Raman shift when the above sample was annealed. The annealing time was about 1 hour at each temperature. The Raman shift on the vertical axis is the peak of silicon at 520 (cm －１) is set to 0, with negative values ​​indicating tensile directions and positive values ​​indicating compressive directions. Note that although the thermal oxide film relieves the substrate stress, correction is made here to eliminate the influence of the thermal oxide film. In FIG. 5, A is the Raman shift value in the initial state in which no silicon-containing film is formed for comparison, and the others are Raman shift values ​​in states in which the silicon-containing film is formed and then annealed at a predetermined temperature.

[0024] As shown in FIG. 5, in the initial state A where no silicon-containing film is formed, the Raman shift of the substrate is −0.4 cm －１ That is, in the initial state, as shown in FIG. 6, a tensile stress 210 of about 200 MPa is generated on the second surface 202 of the substrate 200. After the silicon-containing film 205 is formed, the Raman shift is −0.5 cm －１ The Raman shift increases slightly, and remains negative when the annealing temperature is below 100°C (B and C in FIG. 5). That is, as shown in FIG. 7, tensile stress 210 remains generated on the second surface 202 of the substrate 200. However, the Raman shift changes significantly when the annealing temperature is between 100°C and 200°C, and becomes positive at 200°C (D in FIG. 5). That is, as shown in FIG. 8, the stress generated on the second surface 202 of the substrate 200 changes from tensile stress 210 to compressive stress 220. When the annealing temperature is 200°C or higher, the Raman shift does not change significantly, but at 400°C, the Raman shift increases to +0.5 cm. －１ This indicates that the Raman shift is approximately −0.5 cm by annealing the silicon-containing film at a temperature of about 100 to 400° C., particularly about 100 to 200° C. －１ +0.5cm from －１ The change amount is 1.0 cm. －１ When the stress was calculated from the change in the Raman shift using equation (1), it was found to be 500 MPa or more, and it was confirmed that an extremely large stress can be generated in a film having a relatively thin thickness of 50 nm.

[0025] That is, it was confirmed that the silicon-containing film formed on the substrate using the high order silane gas as the film formation gas at a temperature at which the high order silane liquefies according to this embodiment is a film that can generate extremely large stress on the substrate.

[0026] It has been known for some time that film stress is applied to the substrate during the process of forming devices on one side (first side) of a wafer, which serves as a substrate. Repeated film formation and etching to form patterns is known to impose film stress on the substrate. While thickening the wafer substrate is an effective way to mitigate the effects of such stress, this is difficult to achieve with technologies that require thinning the wafer, such as the recent wafer bonding technology. Furthermore, the presence of numerous stressed films can lead to pattern shifts and misalignment during exposure. For this reason, a technology has been proposed, such as that described in Patent Document 1, in which a film is formed on the second side of the substrate opposite the first side to generate stress in the substrate, thereby alleviating the substrate stress.

[0027] However, as described in Patent Document 1, conventionally, films formed on the second surface are formed by general CVD or ALD, which does not generate a significant amount of stress in the substrate, and the only solution is to increase the film thickness. Furthermore, when forming films by CVD or ALD, the compressive stress generated in the substrate can be somewhat increased by forming the film at a high temperature, but the effect is limited, and film formation at high temperatures is generally restricted due to the impact on devices.

[0028] In contrast to this, in this embodiment, a high-order silane gas is used as the film-forming gas, and a film is formed on the second surface of the substrate at a temperature at which the high-order silane gas liquefies, thereby obtaining a silicon-containing film with high shrinkability, and this film can be significantly shrunk by annealing or the like, thereby imparting a large stress to the substrate. Therefore, a desired stress can be imparted to the substrate without increasing the film thickness as in films formed by general CVD or ALD, and further, the low-temperature film formation does not cause the inconvenience of high-temperature film formation.

[0029] 9 is a cross-sectional view showing an example of a substrate processing apparatus used in carrying out the first embodiment. In this embodiment, the substrate processing apparatus 100 is configured as a film formation apparatus that forms a silicon-containing film at a low temperature on a second surface of the substrate W, the second surface being opposite to the first surface on which devices are formed, by capacitively coupled plasma.

[0030] The substrate processing apparatus 100 has a substantially cylindrical chamber 10 that defines a processing space 11. The chamber 10 is made of metal, for example, aluminum whose surface has been anodized, and is installed in a safety manner.

[0031] A cylindrical metal support table 14 is disposed at the bottom of the chamber 10 via an insulating plate 12, and a mounting table 16 made of metal, such as aluminum, is provided on the support table 14. The mounting table 16 constitutes a lower electrode. The mounting table 16 has an electrostatic chuck 18 on its upper portion. The electrostatic chuck 18 has a structure in which an electrode 20 is provided inside an insulator, and by applying a DC voltage from an attraction DC power supply 22 to the electrode 20, the substrate W is attracted and held by electrostatic force such as Coulomb force. The substrate W is placed on the mounting table 16 so that its second surface serves as a gas supply surface.

[0032] A focus ring 24 made of a conductive material, such as silicon, is disposed around the electrostatic chuck 18. A cylindrical inner wall member 26 made of an insulator, such as quartz, is provided on the side surfaces of the mounting table 16 and the support table 14.

[0033] A coolant chamber 28 is provided inside the support table 14, and a low-temperature coolant is circulated and supplied to the coolant chamber 28 from an external chiller unit (not shown) via pipes 30 a and 30 b, so that the temperature of the substrate W on the mounting table 16 is controlled to a low temperature, for example, −30° C., at which a high-order silane gas supplied as a film-forming gas is liquefied. Furthermore, a heat transfer gas, for example, He gas, is supplied between the upper surface of the electrostatic chuck 18 and the back surface of the substrate W via a gas supply line 32.

[0034] An upper electrode 34 is provided above the mounting table 16, which serves as a lower electrode, so as to face the mounting table 16. The upper electrode 34 is supported on the upper part of the chamber 10 via an insulating shielding member 43. The upper electrode 34 is composed of an electrode plate 36, which forms the surface facing the mounting table 16 and has numerous gas outlet holes 37, and a water-cooled electrode support 38 that detachably supports the electrode plate 36. The electrode plate 36 is made of a conductor, such as silicon. A gas diffusion chamber 40 is provided inside the electrode support 38, and numerous gas flow holes 41 extending downward from the gas diffusion chamber 40 and communicating with the gas outlet holes 37. The electrode support 38 is formed with a gas inlet 42 that introduces gases such as film formation gases into the gas diffusion chamber 40. Gas pipes 51 extending from a gas supply unit 50, described below, are connected to the gas inlet 42. In other words, the upper electrode 34 functions as a showerhead that introduces gases such as film formation gases into the processing space 11.

[0035] A first high-frequency power supply 88 for generating plasma is electrically connected to the upper electrode 34. A matching box 87 is provided on a power feed line 89 that supplies power from the first high-frequency power supply 88 to the upper electrode 34. When high-frequency power is supplied from the first high-frequency power supply 88 to the upper electrode 34, capacitively coupled plasma is generated between the lower electrode (mounting table 16) and the upper electrode 34. Meanwhile, a second high-frequency power supply 91 for applying a bias to attract ions to the substrate W is electrically connected to the lower electrode (mounting table 16). A matching box 90 is provided on a power feed line 92 that supplies power from the second high-frequency power supply 91 to the lower electrode (mounting table 16). The matching boxes 87 and 90 are used to match the load (plasma) impedance to the impedance on the first and second high-frequency power supplies 88 and 91 sides, respectively. The first high-frequency power supply 88 for generating plasma has a higher frequency than the second high-frequency power supply 91 for applying a bias.

[0036] The gas supply unit 50 supplies a high-order silane gas, which is a film-forming gas for forming a silicon-containing film on the second surface of the substrate W. The gas supply unit 50 also supplies a purge gas, a pressure adjusting gas, and a plasma generating gas made of a rare gas such as Ar gas. ２A gas containing Si may be supplied. ２ H ６ , Si ３ H ８ , Si ４ H １０ etc., general formula Si ｎ H ２ｎ＋２ (n is a positive integer of 2 or more), and although any of these can be used, a film with greater shrinkage capacity can be obtained by using one where n is 4 or more. The gas supply unit 50 has gas supply sources corresponding to the multiple gases to be supplied, and individual pipes extending from each gas supply source are connected to a gas pipe 51. An open / close valve and a flow rate controller are interposed in each individual pipe.

[0037] An exhaust port 60 is provided at the bottom of the chamber 10, and an exhaust device 64 is connected to the exhaust port 60 via an exhaust pipe 62. The exhaust device 64 includes an automatic pressure control valve and a vacuum pump, and is configured to evacuate the inside of the chamber 10 and control the pressure therein to a desired vacuum level. A load / unload port 65 is provided in a sidewall of the chamber 10 for loading and unloading a substrate W into and from the chamber 10, and the load / unload port 65 is opened and closed by a gate valve 66.

[0038] The substrate processing apparatus 100 includes a control unit 70. The control unit 70 is configured as a computer and includes a main control unit equipped with a CPU, input devices (keyboard, mouse, etc.), output devices (printer, etc.), display devices (display, etc.), and a storage device (storage medium). The main control unit controls, for example, high-frequency power supplies 88 and 91, the opening and closing valve of the gas supply unit 50, the flow rate controller, the automatic pressure control valve, the suction DC power supply 22, the chiller unit, the gate valve 66, etc. These control operations by the main control unit are executed according to a process recipe, which is a control program stored in a storage medium (hard disk, optical disk, semiconductor memory, etc.) built into the storage device.

[0039] In the substrate processing apparatus 100 configured as described above, a substrate W is loaded into the chamber 10 and placed on the mounting table 16 with its second surface facing up. An inert gas is then supplied from the gas supply unit 50 into the chamber 10, and the pressure inside the chamber 10 is reduced by the exhaust unit 64. In this state, a plasma generating gas, such as Ar gas, is supplied from the gas supply unit 50 into the chamber 10, while plasma generating high-frequency power is applied from the first high-frequency power supply 88 to the upper electrode 34. This generates a capacitively coupled plasma between the upper electrode 34 and the lower electrode, i.e., the mounting table 16. The plasma generating gas may be used as the inert gas for pressure adjustment. Furthermore, a bias high-frequency power for attracting ions is applied to the mounting table 16 from the second high-frequency power supply 91.

[0040] In this state, high-order silane gas, which is a film-forming gas, is supplied into the chamber 10 from the gas supply unit 50, whereby the high-order silane gas is excited by plasma. The excited high-order silane gas reaches the second surface of the substrate W, which is maintained at a temperature at which the high-order silane liquefies, for example, −30° C., and film formation proceeds by gas-phase polymerization at such a low temperature. This results in the formation of a silicon-containing film that has a high shrinkability and can generate a large stress on the second surface of the substrate W, as described above.

[0041] Second Embodiment [Substrate Processing Method] FIG. 10 is a flowchart showing a substrate processing method according to a second embodiment, and FIGS. 11A to 11C are cross-sectional views of the process steps.

[0042] In this embodiment, a substrate 1 having a first surface 2 on which a device is to be formed is first prepared (step ST11, FIG. 11A). Next, a high-order silane gas is supplied as a deposition gas to a second surface 3 opposite the first surface 2 of the substrate 1, and a silicon-containing film 4 is deposited at a temperature at which the high-order silane gas liquefies (step ST12, FIG. 11B). Next, energy 5 is applied to the silicon-containing film 4, generating stress 6 on the second surface 3 of the substrate 1 (step ST13, FIG. 11C).

[0043] In this embodiment, steps ST11 and ST12 are performed in the same manner as steps ST1 and ST2 in the first embodiment.

[0044] In step ST13, energy 5 is applied to the silicon-containing film 4 to generate stress 6 on the second surface 3 of the substrate 1. That is, applying energy to the silicon-containing film 4 causes the silicon-containing film 4 to shrink, and the resulting force generates stress 6 on the second surface 3 of the substrate 1. As described above, the silicon-containing film 4 has a high shrinkability and is therefore capable of generating large stress. By generating stress on the second surface 3 of the substrate 1 in this manner, it is possible to alleviate stress that occurs in the substrate 1 due to film formation when forming devices on the first surface 2. Furthermore, generating stress on the second surface 3 of the substrate 1 can also actively distort the substrate 1.

[0045] The method for applying energy to silicon-containing film 4 is not particularly limited, and thermal energy, light energy, etc. can be used. In step ST13, by adjusting the amount of energy applied to silicon-containing film 4, the amount of shrinkage of silicon-containing film 4 can be adjusted, and the stress generated on second surface 3 of substrate 1 can be adjusted.

[0046] Annealing can be used as a method for providing energy to a silicon-containing film. During annealing, for example, the amount of energy can be adjusted by adjusting the annealing temperature and / or annealing time, thereby adjusting the stress. Annealing can be thermal annealing or photo annealing. Annealing can be performed using various devices, such as a resistance heating element, a heat lamp, an LED, or a UV light source. The annealing temperature can be 100 to 400°C, with 100 to 200°C being particularly effective. The annealing time can be 10 seconds to 12 hours, for example, about 1 hour.

[0047] In the case of a technique such as that described in Patent Document 1, in which a film that generates stress in the substrate is formed on the second surface of the substrate using general CVD or ALD, it is difficult to adjust the stress after the film is formed. However, in this embodiment, the stress generated in the substrate can be adjusted using a simple technique such as annealing.

[0048] In step ST13, energy may be applied to the entire silicon-containing film 4, or may be applied locally to the silicon-containing film 4. Applying energy to the entire silicon-containing film 4 causes the silicon-containing film 4 to shrink as a whole, generating stress across the entire second surface 3 of the substrate 1. Applying energy locally causes only the portion of the silicon-containing film 4 to which energy is applied to shrink, generating stress locally only in the portion of the second surface 3 of the substrate 1 corresponding to that portion. By generating stress locally in this manner, it is possible to alleviate local stress present on the first surface 2 of the substrate 1, for example.

[0049] The silicon-containing film 4 may be left or removed after generating stress on the second surface 3 of the substrate 1. That is, the silicon-containing film 4 may become unnecessary after generating stress on the substrate 1 and forming a device on the first surface 2. However, leaving the silicon-containing film 4 does not adversely affect the device, and leaving it reduces the effort required for removal. Furthermore, the silicon-containing film 4 is easily removable, and its removal has the advantage of making the entire substrate thinner and improving flatness. Therefore, whether to leave the silicon-containing film 4 or remove it can be determined according to the requirements for device formation. When removing the silicon-containing film 4, a step of removing the silicon-containing film 4 is performed after a step of applying energy 5 to the silicon-containing film 4 to generate stress 6 on the second surface 3 of the substrate 1 (step ST13).

[0050] [Substrate Processing System] Fig. 12 is a plan view schematically showing an example of a substrate processing system used in carrying out the second embodiment. The substrate processing system 300 shown in Fig. 12 is a cluster structure (multi-chamber type) system, and includes a substrate processing apparatus 310, an annealing apparatus 320, a transfer chamber 330, a transfer apparatus 340, a load lock chamber 350, a loader module 360, and an overall control unit 370.

[0051] The substrate processing apparatus 310 supplies a high-order silane gas as a film-forming gas to the second surface of the substrate W at a temperature at which the gas liquefies, and forms a silicon-containing film on the second surface, and may be configured in the same manner as the substrate processing apparatus 100 of the first embodiment.

[0052] The annealing device 320 anneals the silicon-containing film formed on the second surface of the substrate to impart energy to the silicon-containing film, thereby generating stress on the second surface of the substrate W. An example of the annealing device 320 will be described later.

[0053] The transfer chamber 330 is maintained at a predetermined vacuum atmosphere, and is provided therein with a transfer device 340 that transfers the substrate W. The transfer chamber 330 is connected to the above-mentioned substrate processing apparatus 310 and annealing apparatus 320, as well as the load lock chamber 350, via gate valves (not shown). The transfer device 340 transfers the substrate W between the substrate processing apparatus 310, the annealing apparatus 320, and the load lock chamber 350.

[0054] The load lock chamber 350 is provided between the loader module 360 ​​and the transfer chamber 330 and is switchable between an atmospheric and a vacuum atmosphere. The loader module 360 ​​is connected to the load lock chamber 350 via a gate valve (not shown) and is located adjacent to the load lock chamber 350. The load lock chamber 350 has an atmospheric atmosphere and is equipped with a transfer device (not shown). A load port is provided on the wall of the loader module 360 ​​opposite the load lock chamber 350, and a carrier (e.g., a front-opening unified pod (FOUP)) containing or emptying a substrate W is attached to the load port. The transfer device of the loader module 360 ​​transfers the substrate W between the load lock chamber 350 and the carrier attached to the load port.

[0055] The overall control unit 370 is configured as a computer, and has a main control unit with a CPU, input devices (keyboard, mouse, etc.), output devices (printer, etc.), display devices (display, etc.), and storage devices (storage media). The main control unit controls the processing of the substrate processing apparatus 310 and the annealing apparatus 320, the transport device 340 and the transport device of the loader module 360, opening and closing of the gate valve, etc. The overall control unit 370 may be configured as a host control unit of the control units of the substrate processing apparatus 310 and the annealing apparatus 320.

[0056] In the substrate processing system 300, first, a transfer device (not shown) in the loader module 360 ​​takes out a substrate W from a carrier connected to a load port and loads it into the load lock chamber 350 under atmospheric conditions.

[0057] The load lock chamber 350 is then evacuated, and the substrate W in the load lock chamber 350 is transferred into the substrate processing apparatus 310 by the transfer device 340. In the substrate processing apparatus 310, a high-order silane gas serving as a film-forming gas is supplied to the second surface of the substrate W at a temperature sufficient to liquefy the gas, thereby forming a silicon-containing film on the second surface. The transfer device 340 then transfers the substrate W on which the silicon-containing film has been formed from the substrate processing apparatus 310 and into the annealing apparatus 320. In the annealing apparatus 320, the silicon-containing film formed on the second surface of the substrate W is annealed to shrink it, thereby generating stress in the second surface of the substrate. The transfer device 340 then transfers the annealed substrate W out and into the load lock chamber 350.

[0058] Then, the load lock chamber 350 is returned to the atmospheric air, and the substrate W in the load lock chamber 350 is returned to the carrier by the transport device in the loader module 360 ​​.

[0059] The above-described processing is performed simultaneously in parallel on a plurality of substrates W until the processing of the plurality of substrates W in the carrier is completed.

[0060] 13 is a cross-sectional view showing an example of an annealing apparatus 320. The annealing apparatus 320 includes a chamber (not shown), a mounting table 110 for mounting a substrate W thereon, which is provided in the chamber, a heating mechanism 140 for heating using an LED, and a control unit 160.

[0061] The mounting table 110 has a top plate 120 as a top plate portion and a flow path forming member 130. The top plate 120 is attached to the top of the flow path forming member 130 via a seal ring 131. The substrate W has a silicon-containing film formed on a second surface thereof, and is adsorbed and held on the surface of the top plate 120 with the silicon-containing film facing downward.

[0062] A plurality of temperature sensors 121 are embedded in the top plate 120 at positions spaced apart from one another in a plan view. The top plate 120 is formed in the shape of a disk having a diameter approximately the same as that of the substrate W, and is made of, for example, SiC. SiC has high thermal conductivity and Young's modulus, and also has high absorption efficiency for light from LEDs 141 of the heating mechanism 140 (described later), allowing for efficient heating by light from the heating mechanism 140.

[0063] The flow path forming member 130 is formed in a disk shape with approximately the same diameter as the top plate 120 and is made of a material transparent to the wavelength of light from an LED (described later). A groove for flowing a temperature control medium is formed in the upper part of the flow path forming member 130, and this groove is covered by the top plate 120 to form a temperature control medium flow path R. A supply port 132 for supplying a temperature control medium to the temperature control medium flow path R and a discharge port 133 for discharging the temperature control medium are formed in the side of the flow path forming member 130. A temperature control medium supply pipe 150 and a temperature control medium discharge pipe 151 are connected to these, respectively, so that the temperature control medium is circulated and supplied to the temperature control medium flow path R. A valve 152 is provided on the temperature control medium supply pipe 150. By flowing a temperature control medium at a predetermined temperature through the temperature control medium flow path R, the base temperature of the mounting table 110 is adjusted to the predetermined temperature.

[0064] The heating mechanism 140 is configured as a light irradiation mechanism, and is disposed on the surface of the mounting table 110 opposite the substrate mounting surface, i.e., facing the lower surface of the flow path forming member 130, so as to correspond to the substrate W mounted on the top plate 120. The heating mechanism 140 has a plurality of LEDs 141 as a heat source, and irradiates the top plate 120 of the mounting table 110 with light from the LEDs, thereby heating the silicon-containing film of the substrate W mounted thereon via the top plate 120.

[0065] Each LED 141 emits, for example, near-infrared light. The light emitted from the LEDs 141 passes through a flow path forming member 130 of the mounting table 110, which is made of a light-transmitting member. The temperature control medium flowing through the temperature control medium flow path R is made of a material that transmits the light from the LEDs 141, and the light that has passed through the flow path forming member 130 and the temperature control medium is incident on the top plate 120. When the light from the LEDs 141 is near-infrared light, the light-transmitting member that constitutes the flow path forming member 130 can be made of polycarbonate, quartz, polyvinyl chloride, acrylic resin, or glass.

[0066] The heating mechanism 140 is configured by arranging a plurality of LED units 143, each of which is a unit formed by arranging a plurality of LEDs 141 as heat sources, with almost no gaps between them on a base portion 142. Each LED unit 143 can be independently controlled for on / off and light intensity, making it possible to heat the substrate W uniformly or locally. In addition, by controlling the light intensity of the LEDs 141 of the LED unit 143, it is possible to control the annealing temperature of the substrate W. A coolant flow path may be provided in the base portion 142 so that the substrate W can be cooled by a coolant.

[0067] The control unit 160 is configured as a computer and includes a main control unit with a CPU, input devices (keyboard, mouse, etc.), output devices (printer, etc.), display devices (display, etc.), and storage devices (storage media). The main control unit performs, for example, on / off control and light intensity control of the LEDs 141 for each LED unit 143, and flow rate control of the temperature control medium. These control operations by the main control unit are executed by a processing recipe, which is a control program stored in a storage medium (hard disk, optical disk, semiconductor memory, etc.) built into the storage device.

[0068] The annealing apparatus 320 configured in this manner can perform an annealing process on the entire or localized portion of the silicon-containing film formed on the second surface of the substrate W, causing the silicon-containing film to shrink and generating stress on the entire or localized portion of the second surface of the substrate W.

[0069] The substrate processing system 300 is an example in which a device for forming a silicon-containing film and a device for annealing for stress generation are connected to a transfer chamber in a cluster structure, and the processes are performed in situ by these devices. However, the present invention is not limited to this, and the substrate processing system may be configured by providing these devices separately. Furthermore, the annealing device is not limited to one that uses an LED, and a resistance heating element, a heat lamp, or a UV light source may also be used. Furthermore, the annealing device is not limited to one that uses an LED, and any device that can impart energy to the silicon-containing film may be used.

[0070] Third Embodiment [Substrate Processing Method] FIG. 14 is a flowchart showing a substrate processing method according to a third embodiment, and FIGS. 15A to 15D are cross-sectional views of the process steps.

[0071] In this embodiment, first, a substrate 1 having a first surface 2 on which a device is to be formed is prepared (step ST21, FIG. 15A). Next, the stress distribution on the second surface 3 of the substrate 1, opposite the first surface 2, is measured (step ST22). This stress distribution measurement may be performed over the entire second surface 3 of the substrate 1 or over a portion of the second surface 3. For example, as shown in FIG. 15B, the stress distribution may be measured by scanning the stress measurement unit 7 over the second surface 3 of the substrate 1. Next, a high-order silane gas is supplied as a deposition gas to the second surface 3 of the substrate 1, and a silicon-containing film 4 is formed at a temperature at which the high-order silane gas liquefies (step ST23, FIG. 15C). Next, energy 5 is locally applied to the silicon-containing film 4 in accordance with the stress distribution measured in step ST22, thereby generating local stress 6 on the second surface 3 of the substrate 1 so as to alleviate the measured stress distribution (step ST24, FIG. 15D).

[0072] In this embodiment, steps ST21 and ST23 are performed in the same manner as steps ST1 and ST2 in the first embodiment.

[0073] In step ST22, the method for measuring the stress distribution on the second surface 3 of the substrate 1 is not particularly limited, but measurement by Raman spectroscopy can be used. When the substrate is, for example, a Si substrate, the stress of the substrate 1 can be measured by irradiating the substrate 1 with laser light to obtain the spectrum of Raman scattered light (Raman spectrum), and measuring the peak of 520 (cm) of Si crystal (crystal not subjected to stress). －１ ) can be calculated by the above formula (1). The stress distribution on the second surface 3 of the substrate 1 can be measured by scanning the second surface 3 with laser light using a stress measurement unit having a laser light source, an objective lens, a spectroscope, a detector, etc. That is, the stress distribution can be determined by scanning the second surface 3 of the substrate 1 with laser light, measuring the Raman spectrum from the Raman scattered light, determining the Raman shift of the silicon peak at each position on the second surface 3 of the substrate 1, and calculating the stress at each position.

[0074] In step ST24, based on the stress distribution on the second surface 3 of the substrate 1 measured in step ST22, energy is locally applied to the silicon-containing film 4 to shrink it, thereby generating stress on the second surface 3 of the substrate 1 so as to alleviate the measured stress distribution. That is, in step ST24, energy is locally applied to the silicon-containing film 4 at the location on the second surface 3 of the substrate 1 where the stress was measured, so as to generate stress that alleviates the stress distribution. As a method for locally applying energy in this manner, for example, local annealing using an LED as described above can be used. Alternatively, local annealing can be performed by scanning a UV light source or a heat lamp.

[0075] As described above, conventionally, when forming a device on one side (first side) of a wafer, which is a substrate, a pattern is formed by repeatedly forming a film and etching. Recently, the patterns formed have become more complex, and after or during the formation of a device with a desired pattern, complex stresses are generated in the film that constitutes the pattern, which in turn generates a complex and non-uniform stress distribution in the substrate.

[0076] For this reason, in this embodiment, the stress distribution on the second surface 3 of the substrate 1 is measured, and then the silicon-containing film 4 having a large shrink capacity as described above is formed, and annealing or the like is performed locally on the silicon-containing film 4 in accordance with the stress distribution. This local annealing or the like causes the annealed portion of the silicon-containing film 4 to shrink, thereby generating local stress on the second surface 3 of the substrate 1 so as to alleviate the measured stress distribution of the substrate.

[0077] A stress relaxation film formed on the second surface of a substrate by typical CVD or ALD, as described in Patent Document 1, alone cannot address the complex and non-uniform stress distribution resulting from such patterns. To use such a technique to relieve the non-uniform stress distribution, pattern formation on the stress relaxation film, for example, using photolithography, is required, resulting in an extremely complicated process and limited effectiveness. In contrast, the present embodiment can relieve non-uniformly distributed stress using a simple method such as annealing in accordance with the measured stress distribution. Furthermore, the present embodiment can generate large stress by shrinking the silicon-containing film, and the magnitude of the generated stress can be adjusted, resulting in a significant stress relaxation effect in response to the non-uniform stress distribution.

[0078] 16 is a plan view schematically showing an example of a substrate processing system used in carrying out the third embodiment. The substrate processing system 400 shown in Fig. 16 is a cluster structure (multi-chamber type) system, and includes a substrate processing apparatus 410, an annealing apparatus 420, a stress measurement apparatus 480, a transfer chamber 430, a transfer apparatus 440, a load lock chamber 450, a loader module 460, and an overall control unit 470.

[0079] The substrate processing apparatus 410 supplies a high-order silane gas as a film-forming gas to the second surface of the substrate W at a temperature at which the gas liquefies, and forms a silicon-containing film on the second surface of the substrate W, and may be configured in the same manner as the substrate processing apparatus 100 of the first embodiment.

[0080] The annealing apparatus 420 locally anneals the silicon-containing film formed on the second surface of the substrate W in accordance with the stress distribution measured by the stress measurement apparatus 480 described below, thereby generating local stress on the second surface of the substrate W so as to relieve the measured stress. The annealing apparatus 420 may be configured similarly to the annealing apparatus 320 of the second embodiment, which is capable of local annealing.

[0081] As shown in FIG. 17 , the stress measurement apparatus 480 includes a stage 501 for supporting a substrate W, a laser light source 502, an objective lens 503, a spectrometer 504, a multichannel detector 505 for measuring a spectrum, and a control unit 506. The substrate W is placed on the stage 501 with its second surface facing up. The stage 501 is freely movable within a plane, allowing the laser light to scan the second surface of the substrate W. The laser light may be scanned by moving the optical system. The laser light from the laser light source 502 is irradiated onto the second surface of the substrate W via the objective lens 503. Raman scattered light generated from the second surface of the substrate W is then collected by the objective lens 503 and directed to the spectrometer 504, and the Raman spectrum is measured by the multichannel detector 505. The control unit 506 controls each component of the stress measurement apparatus 480 and also functions as a calculation unit. The control unit 506 determines the Raman shift of the silicon peak from the Raman spectrum and calculates the stress.

[0082] The transfer chamber 430 is maintained at a predetermined vacuum atmosphere, and is provided therein with a transfer device 440 that transfers the substrate W. The transfer chamber 430 is connected to the above-mentioned substrate processing apparatus 410, annealing apparatus 420, stress measurement apparatus 480, and load lock chamber 450 via gate valves (not shown). The transfer device 440 transfers the substrate W between the substrate processing apparatus 410, annealing apparatus 420, stress measurement apparatus 480, and load lock chamber 450.

[0083] The load lock chamber 450 and the loader module 460 are configured similarly to the load lock chamber 350 and the loader module 360 ​​of the substrate processing system 300 of the second embodiment. The loader module 460 is provided with a transport device, which transports substrates W between the load lock chamber 450 and a carrier attached to a load port.

[0084] The overall control unit 470 is configured as a computer, and is configured similarly to the overall control unit 370 in the substrate processing system 300 of the second embodiment, and controls the processes of the substrate processing apparatus 410, the annealing apparatus 420, and the stress measuring apparatus 480, the transport apparatus 440 and the transport apparatus of the loader module 460, the opening and closing of gate valves, etc. The overall control unit 470 also stores the stress distribution measured by the stress measuring apparatus 480, and issues a command to the annealing apparatus 420 regarding the portion to be annealed accordingly. The overall control unit 470 may be configured as a host control unit of the control units of the substrate processing apparatus 410, the annealing apparatus 420, and the stress measuring apparatus 480.

[0085] In the substrate processing system 400, first, a transfer device (not shown) in the loader module 460 removes a substrate W from a carrier connected to a load port and loads it into the atmospheric load lock chamber 450. The substrate W may have a device formed on its first surface, or may have a pattern formed in the middle of device formation.

[0086] The load lock chamber 450 is then evacuated, and the substrate W in the load lock chamber 450 is loaded into the stress measurement device 480 with the second surface facing up by the transport device 440. The stress measurement device 480 measures the stress distribution over the entire or part of the second surface of the substrate W. The stress distribution measurement results are stored in the overall control unit 470. The transport device 440 then unloads the substrate W, whose stress distribution has been measured, from the stress measurement device 480 and loads it into the substrate processing apparatus 410. In the substrate processing apparatus 410, a high-order silane gas is supplied as a film formation gas to the second surface of the substrate W at a temperature sufficient to liquefy the gas, thereby forming a silicon-containing film on the second surface. The transport device 440 then unloads the substrate W, on which the silicon-containing film has been formed, from the substrate processing apparatus 410 and loads it into the annealing device 420. In the annealing device 420, local annealing is performed on the silicon-containing film 4 in accordance with the stress distribution measurement results of the stress measurement device 480 stored in the overall control unit 470. This local annealing causes the annealed portion of the silicon-containing film to shrink, generating local stress on the second surface of the substrate W so as to alleviate the stress distribution of the substrate W measured by the stress measurement device 480. Thereafter, the transfer device 440 unloads the annealed substrate W and transfers it to the load lock chamber 450.

[0087] Then, the load lock chamber 450 is returned to the atmospheric air, and the substrate W in the load lock chamber 450 is returned to the carrier by the transport device in the loader module 460 .

[0088] The above-described processing is performed simultaneously in parallel on a plurality of substrates W until the processing of the plurality of substrates W in the carrier is completed.

[0089] The substrate processing system 400 is an example in which a cluster structure is used in which a device for forming a silicon-containing film, a device for annealing for stress generation, and a stress measurement device are connected to a transfer chamber, and the processes are performed in situ using these devices. However, the present invention is not limited to this, and the substrate processing system may also be configured by providing these devices separately. Furthermore, the annealing device is not limited to one that uses an LED, and any device that can perform localized heating may be used, such as a UV light source or a heat lamp. Furthermore, the annealing device is not limited to one that uses an LED, and any device that can provide energy to the silicon-containing film may be used.

[0090] Although the embodiments have been described above, the disclosed embodiments should be considered to be illustrative and not restrictive in all respects. The above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims.

[0091] For example, in the above embodiment, the silicon-containing film formed on the second surface of the substrate includes a Si film and a SiO ２ However, the present invention is not limited to this and may be any other Si-containing film such as a SiN film.

[0092] Furthermore, in the above embodiment, an apparatus that cools a substrate using a mounting table and processes the substrate using capacitively coupled plasma has been exemplified as a substrate processing apparatus for forming a silicon-containing film, but the present invention is not limited to this. For example, the substrate cooling method is not limited to a method that uses a mounting table, as long as the film can be formed at a temperature at which the high-order silane gas liquefies. Furthermore, the plasma is not limited to capacitively coupled plasma, and may be inductively coupled plasma, microwave plasma, or remote plasma. Furthermore, a method that does not use plasma may be used as long as the film can be formed at a temperature at which the high-order silane gas liquefies.

[0093] Furthermore, the annealing device and stress measuring device are merely examples, and their configurations are not limited as long as they can achieve the intended purpose.

[0094] REFERENCE SIGNS LIST 1; substrate, 2; first surface, 3; second surface, 4; silicon-containing film, 5; energy, 6; stress, 7; stress measurement unit, 10; chamber, 16; mounting table (lower electrode), 28; coolant chamber, 34; upper electrode, 50; gas supply unit, 70, 160, 506; control unit, 88, 91; high-frequency power source, 100, 310, 410; substrate processing apparatus, 300, 400; substrate processing system, 320, 420; annealing apparatus, 330, 430; transfer chamber, 340, 440; transfer device, 350, 450; load lock chamber, 360, 460; loader module, 370, 470; overall control unit, 480; stress measurement device, W; substrate

Claims

1. A substrate processing method comprising: preparing a substrate having a first surface on which a device is to be formed; and depositing a silicon-containing film on a second surface of the substrate opposite the first surface using a high order silane gas as a deposition gas at a temperature at which the high order silane gas is liquefied.

2. The substrate processing method of claim 1, wherein forming the silicon-containing film comprises placing the substrate on a mounting table in a chamber, maintaining the mounting table at a temperature at which the high-order silane gas is liquefied, and introducing the high-order silane gas into the chamber and supplying it to the second surface of the substrate, thereby forming the silicon-containing film on the second surface.

3. The substrate processing method according to claim 2, wherein the high order silane gas is supplied to the second surface of the substrate in a state excited by plasma.

4. The method of claim 1, further comprising, after depositing the silicon-containing film, applying energy to the silicon-containing film to generate stress on the second surface of the substrate.

5. The substrate processing method according to claim 4, wherein when energy is applied to the silicon-containing film, the silicon-containing film shrinks, thereby generating stress on the second surface of the substrate.

6. The substrate processing method according to claim 5, wherein, when generating stress on the second surface of the substrate, an amount of shrinkage of the silicon-containing film is controlled by an amount of energy applied to the silicon-containing film, thereby controlling the stress generated on the second surface of the substrate.

7. The substrate processing method according to claim 5, wherein generating stress on the second surface of the substrate comprises applying energy to the silicon-containing film by annealing the silicon-containing film.

8. The substrate processing method according to claim 7, wherein, when generating stress on the second surface of the substrate, the amount of shrinkage of the silicon-containing film is controlled by the temperature and / or time of the annealing, thereby controlling the stress generated on the second surface of the substrate.

9. The substrate processing method of claim 4, further comprising measuring a stress distribution on the second surface before depositing the silicon-containing film, and applying energy to the silicon-containing film to generate stress on the second surface of the substrate comprises locally applying energy to the silicon-containing film in accordance with the measured stress distribution to locally generate stress on the second surface of the substrate such that the measured stress distribution is alleviated.

10. The substrate processing method according to claim 9, wherein measuring the stress distribution comprises calculating the stress on the second surface of the substrate from a shift amount of a crystal peak of a Raman spectrum by Raman spectroscopy.

11. The substrate processing method according to claim 9, wherein applying energy to the silicon-containing film to generate stress on the second surface of the substrate is performed by using, as a heat source, LED units each having a plurality of LEDs arranged as a unit in such a manner that they correspond to the silicon-containing film formed on the second surface of the substrate, and turning the LED units on and off to locally heat the silicon-containing film.

12. A substrate processing apparatus comprising: a chamber for accommodating a substrate having a first surface on which a device is formed; a mounting table for mounting the substrate so that a second surface of the substrate opposite the first surface becomes a gas supply surface; a gas supply unit for supplying high-order silane gas as a film formation gas to the substrate; and cooling means for cooling the substrate via the mounting table to a temperature at which the high-order silane gas is liquefied; wherein the high-order silane gas is supplied to the second surface of the substrate and a silicon-containing film is formed on the second surface of the substrate.

13. The substrate processing apparatus according to claim 12, further comprising plasma generating means for exciting said high order silane gas.

14. A substrate processing system comprising: a substrate processing apparatus according to claim 12; and a device for applying energy to the silicon-containing film deposited by the substrate processing apparatus to generate stress on the second surface of the substrate.

15. The substrate processing system of claim 14, wherein the device for applying energy to the silicon-containing film to generate stress on the second surface of the substrate is an annealing device.

16. The substrate processing system according to claim 15, wherein the annealing device controls the stress generated on the second surface of the substrate by controlling the annealing temperature and / or time.

17. The substrate processing system of claim 14, further comprising a stress measuring device that measures a stress distribution on the second surface before a silicon-containing film is formed by the substrate processing apparatus, and the device that applies energy to the silicon-containing film to generate stress on the second surface of the substrate applies energy locally to the silicon-containing film in accordance with the measured stress distribution, thereby generating stress locally on the second surface of the substrate so as to alleviate the measured stress distribution.

18. The substrate processing system according to claim 17, wherein the stress measuring device calculates the stress on the second surface of the substrate from a shift amount of a crystal peak of a Raman spectrum obtained by Raman spectroscopy.

19. The substrate processing system of claim 17, wherein the device that applies energy to the silicon-containing film to generate stress on the second surface of the substrate has a heat source in which a plurality of LED units, each unitized with a plurality of LEDs, are arranged in a manner corresponding to the silicon-containing film formed on the second surface of the substrate, and the silicon-containing film is locally heated by turning on and off the LED units.

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