Method for forming polycrystalline silicon film

Abstract

To provide a technique capable of forming an amorphous silicon film having a uniform film thickness.SOLUTION: A film forming method forms an amorphous silicon film on a substrate. In the film forming method, a monosilane (SiH4) gas is supplied into a processing container containing the substrate, (a) the temperature in the processing container is set to a range of 300°C or higher and 440°C or lower, and (b) a film forming process is performed under a process condition in which the pressure in the processing container is set in the range of 10 Torr or more and 100 Torr or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This disclosure , many The present invention relates to a method for forming a crystalline silicon film. [Background technology]

[0002] A technique is known in which an amorphous silicon film doped with impurities that suppress the progress of crystallization and an undoped amorphous silicon film are stacked in this order on an insulating film, and then the stacked amorphous silicon films are crystallized (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-255894 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a technique that can form an amorphous silicon film with a uniform thickness. [Means for solving the problem]

[0005] According to one aspect of the present disclosure, The method includes the steps of forming a first amorphous silicon film on a substrate, forming a second amorphous silicon film covering the first amorphous silicon film, and heating the substrate, wherein the step of forming the first amorphous silicon film on the substrate includes filling a processing vessel containing the substrate with SiH 4 a step of forming a second amorphous silicon film on the substrate at a temperature higher than that of the first amorphous silicon film on the substrate; is provided. (a) setting the temperature inside the processing vessel in the range of 300°C to 440°C; (b) setting the pressure in the processing vessel to a range of 10 Torr or more and 100 Torr or less; [Effects of the Invention]

[0006] According to one embodiment, an amorphous silicon film having a uniform film thickness can be formed. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a flowchart illustrating a method for forming a polycrystalline silicon film according to an embodiment. [Figure 2] FIG. 4 is a schematic cross-sectional view showing the substrate after the second film-forming step. [Figure 3] 1 is a schematic diagram showing an example of a processing apparatus for performing a method for forming a polycrystalline silicon film. [Figure 4] 4A and 4B are graphs showing the relationship between the temperature and the hydrogen concentration in the film during the film formation process, respectively, and the relationship between the pressure and the hydrogen concentration in the film during the film formation process. [Figure 5] Fig. 5(A) is a cross-sectional view illustrating a seed layer and a bulk layer in a recess formed by the film formation process of this embodiment. Fig. 5(B) is a cross-sectional view illustrating a seed layer and a bulk layer in a recess formed by a conventional film formation process. Fig. 5(C) is a graph for comparing the film thickness of the seed layer formed in the recess. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and redundant explanations may be omitted.

[0009] 1, a method for forming a polycrystalline silicon film according to an embodiment of the present disclosure sequentially performs a first film formation step S1, a second film formation step S2, and a crystallization step S3. The film formation method according to an embodiment of the present disclosure relates to the film formation process of the first film formation step S1.

[0010] 2, the substrate 100 on which the polycrystalline silicon film forming method is performed is, for example, a semiconductor wafer applied to a memory such as VNAND. Note that the substrate 100 may be used for purposes other than memory.

[0011] The substrate 100 has an insulating film (underlayer) 110 on its surface. The insulating film 110 insulates the gate in the memory. Examples of the insulating film 110 include a silicon oxide film (SiO2 film) and a silicon nitride film (SiN film). In a method for forming a polycrystalline silicon film, an amorphous silicon film is formed on the insulating film 110. When forming the amorphous silicon film, it is preferable that the surface of the insulating film 110 is coated with an organic silane such as aminosilane.

[0012] When the steps up to the second film-forming step S2 are performed, a first amorphous silicon film (seed layer 121) and a second amorphous silicon film (bulk layer 122) are stacked on the insulating film 110. That is, the method for forming the polycrystalline silicon film includes forming the seed layer 121 on the insulating film 110 in the first film-forming step S1, and forming the bulk layer 122 on the seed layer 121 in the second film-forming step S2.

[0013] In the crystallization step S3, the substrate 100 having the seed layer 121 and the bulk layer 122 is heated to a predetermined temperature to crystallize the seed layer 121 and the bulk layer 122. As a result, a polycrystalline silicon film is formed on the insulating film 110 of the substrate 100.

[0014] An example of a processing apparatus 1 for carrying out the above-described method for forming a polycrystalline silicon film will now be described with reference to Fig. 3. The processing apparatus 1 is a batch-type apparatus that processes a plurality of substrates 100 having insulating films 110 at once.

[0015] The processing apparatus 1 includes a processing vessel 10, a gas supply unit 30, an exhaust unit 40, a heating unit 50, a control unit 80, and the like.

[0016] The processing vessel 10 can have its interior decompressed and accommodates a substrate 100. The processing vessel 10 has a cylindrical inner tube 11 with a ceiling and an open bottom end, and a cylindrical outer tube 12 with a ceiling and an open bottom end that covers the outside of the inner tube 11. The inner tube 11 and the outer tube 12 are made of a heat-resistant material such as quartz, and are arranged coaxially to form a double-tube structure.

[0017] The ceiling of the inner pipe 11 is, for example, flat. A storage section 13 for storing a gas nozzle is formed on one side of the inner pipe 11 along its longitudinal direction (vertical direction). The storage section 13 is an area within a protrusion 14 formed by protruding part of the side wall of the inner pipe 11 outward.

[0018] A rectangular opening 15 is formed in the side wall of the inner tube 11 opposite the housing portion 13 along its longitudinal direction (vertical direction).

[0019] The opening 15 is a gas exhaust port formed so as to be able to exhaust gas from the inner tube 11. The length of the opening 15 is the same as the length of the wafer boat 16 or is formed so as to extend in the vertical direction longer than the length of the wafer boat 16.

[0020] The lower end of the processing vessel 10 is supported by a cylindrical manifold 17 made of, for example, stainless steel. A flange 18 is formed at the upper end of the manifold 17, and the lower end of the outer tube 12 is placed on the flange 18 to support it. A seal member 19 such as an O-ring is interposed between the flange 18 and the lower end of the outer tube 12 to keep the inside of the outer tube 12 airtight.

[0021] An annular support 20 is provided on the inner wall of the upper portion of the manifold 17, and the lower end of the inner tube 11 is placed and supported on the support 20. A lid 21 is airtightly attached to the opening at the lower end of the manifold 17 via a sealing member 22 such as an O-ring, so as to airtightly close the opening at the lower end of the processing vessel 10, i.e., the opening of the manifold 17. The lid 21 is made of, for example, stainless steel.

[0022] A rotation shaft 24 that rotatably supports the wafer boat 16 via a magnetic fluid seal 23 penetrates the center of the lid 21. A lower portion of the rotation shaft 24 is rotatably supported by an arm 25A of a lifting mechanism 25 that is a boat elevator.

[0023] A rotating plate 26 is provided at the upper end of the rotating shaft 24, and a wafer boat 16 holding substrates 100 is placed on the rotating plate 26 via a quartz heat retention stand 27. Therefore, by raising and lowering the lifting mechanism 25, the lid 21 and the wafer boat 16 move up and down together, allowing the wafer boat 16 to be removed from the processing vessel 10. The wafer boat 16 can be accommodated in the processing vessel 10, and holds a plurality of substrates 100 (e.g., 50 to 150 substrates) approximately horizontally with vertical spacing between them.

[0024] The gas supply unit 30 has a gas nozzle 31 that supplies a process gas and a purge gas into the inner tube 11 in the first film formation process S1 and the second film formation process S2 described above. The process gas is monosilane (SiH4) gas, which is a silicon-containing gas. On the other hand, the purge gas may be, for example, nitrogen (N2) gas or argon (Ar) gas.

[0025] The gas nozzle 31 is made of, for example, quartz, and is provided along the vertical direction within the inner tube 11. Its base end is bent into an L shape and supported so as to penetrate through the manifold 17. The gas nozzle 31 has a plurality of gas holes 32 along its longitudinal direction, and discharges processing gas from each gas hole 32 in the horizontal direction. The plurality of gas holes 32 are arranged, for example, at the same intervals as the intervals between the substrates 100 supported on the wafer boat 16. A processing gas with a controlled flow rate is introduced into the gas nozzle 31.

[0026] 3 shows a case where the gas supply unit 30 has one gas nozzle 31, but is not limited thereto, and the gas supply unit 30 may have multiple gas nozzles. For example, the monosilane gas and the purge gas may be supplied into the inner tube 11 from different gas nozzles.

[0027] The exhaust unit 40 exhausts gas that is discharged from the inner tube 11 through the opening 15 and then discharged from a gas outlet 41 via a space P1 between the inner tube 11 and the outer tube 12. The gas outlet 41 is formed on the side wall of the upper part of the manifold 17, above the support unit 20. An exhaust path 42 is connected to the gas outlet 41. A pressure adjustment valve 43 and a vacuum pump 44 are provided in this order downstream on the exhaust path 42, so that the internal pressure in the processing vessel 10 can be adjusted.

[0028] The heating unit 50 is provided to surround the outer tube 12 and is fixed, for example, on the base plate 28. The heating unit 50 has a cylindrical shape so as to cover the outer tube 12. The heating unit 50 includes, for example, a heating element and heats the substrate 100 in the processing chamber 10.

[0029] The control unit 80 controls the operation of each part of the processing apparatus 1. The control unit 80 may be a computer having one or more processors, memory, input / output interfaces, and electronic circuits (not shown). The processor is one or a combination of a CPU, ASIC, FPGA, and a circuit made up of multiple discrete semiconductors. The memory is composed of volatile memory and non-volatile memory. The memory also includes a storage medium 90 (e.g., a compact disc, DVD, hard disk, flash memory, etc.) connected to the control unit 80, and stores a program for operating the processing apparatus 1 and a substrate processing recipe (process conditions).

[0030] Next, a description will be given of the operation of the processing apparatus 1. The method for forming a polycrystalline silicon film is carried out by the control unit 80 controlling the operation of each unit of the processing apparatus 1.

[0031] In the substrate processing of the processing apparatus 1, first, the wafer boat 16 loaded with a plurality of substrates 100 is loaded into the processing vessel 10. Next, the opening at the bottom end of the manifold 17 is closed with the lid 21, thereby making the inside of the processing vessel 10 an airtight space.

[0032] After the sealed space is formed, the processing apparatus 1 performs the first film formation step S1. In the first film formation step S1 according to this embodiment, a film formation process is performed on each substrate 100 under the following process conditions. Processing gas: Monosilane (SiH4) gas Temperature inside the processing vessel 10: 300°C or higher and 440°C or lower Pressure inside the processing vessel 10: 10 Torr (≒ 1.3 kPa) or more 100 Torr (≒ 13 kPa) or less Processing gas flow rate: 0.1 slm or more and 3 slm or less

[0033] That is, the processing apparatus 1 sets the thermal decomposition temperature of the monosilane gas in the first film formation step S1 to a temperature (300°C to 440°C) lower than the thermal decomposition temperature (450°C to 530°C) generally used in conventional film formation processes. The thermal decomposition temperature of the monosilane gas in this first film formation step S1 is a temperature lower than the thermal decomposition temperature of the monosilane gas in the second film formation step S2 described below.

[0034] 4A is a logarithmic graph showing the relationship between the temperature inside the processing vessel 10 and the hydrogen concentration in the film of the seed layer 121 in the first film formation step S1. In the graph, the horizontal axis represents the temperature inside the processing vessel 10, and the vertical axis represents the hydrogen concentration in the film. As can be seen from this graph, in the film formation process using monosilane gas, the lower the temperature inside the processing vessel 10, the higher the hydrogen concentration in the film. In other words, by performing the film formation process in an environment where the thermal decomposition temperature of monosilane gas is low, the seed layer 121 has a large amount of hydrogen contained in the monosilane gas remaining in the film.

[0035] When the hydrogen concentration in the film is increased in this manner, a polycrystalline silicon film with a large grain size can be formed as a result of hydrogen desorption during crystallization in the crystallization step S3. In other words, by heating the substrate 100 at a temperature of 300°C or higher and 440°C or lower to form the seed layer 121 in the first film formation step S1, it is possible to promote the formation of a polycrystalline silicon film with a large grain size.

[0036] Furthermore, in order to prevent the particle size of the silicon nuclei in the seed layer 121 from becoming smaller due to the lowered thermal decomposition temperature of the monosilane gas in the first film formation step S1, the processing apparatus 1 performs the film formation process by maintaining a high pressure within the processing vessel 10. Specifically, as shown in the above process conditions, the processing apparatus 1 sets the pressure within the processing vessel 10 in the first film formation step S1 higher (10 Torr to 100 Torr) than the pressure (5 Torr ≈ 667 Pa or less) typically used in conventional film formation processes. The pressure within the processing vessel 10 in this first film formation step S1 is higher than the pressure within the processing vessel 10 in the second film formation step S2, which will be described later.

[0037] 4(B) is a logarithmic graph showing the relationship between the pressure inside the processing vessel 10 and the hydrogen concentration in the film of the seed layer 121 when the temperature inside the processing vessel 10 is 430°C. In the graph, the horizontal axis represents the pressure inside the processing vessel 10, and the vertical axis represents the hydrogen concentration in the film. As can be seen from this graph, in a film formation process using monosilane gas, if the temperature inside the processing vessel 10 is the same, the hydrogen concentration in the film increases as the pressure inside the processing vessel 10 increases. In other words, by performing the film formation process under an environment with a high pressure inside the processing vessel 10, more hydrogen contained in the monosilane gas remains in the film of the seed layer 121.

[0038] Furthermore, in order to maintain a constant pressure inside the processing vessel 10, the processing apparatus 1 preferably sets the flow rate of the monosilane gas supplied into the processing vessel 10 by the gas supply unit 30 to a range of 0.1 slm to 3 slm. This allows the processing apparatus 1 to stably supply the monosilane gas to each substrate 100 inside the processing vessel 10, thereby allowing the deposition of the seed layer 121 to proceed.

[0039] To perform the process conditions for the first film formation step S1, the control unit 80 controls the exhaust unit 40 to evacuate the processing chamber 10 and maintain the pressure at a predetermined value (e.g., 19 Torr) within the range of 10 Torr to 100 Torr, as specified in the process conditions. The control unit 80 also controls the power supplied to the heating unit 50 to raise the temperature within the processing chamber 10 to a predetermined value (e.g., 380°C) within the range of 300°C to 440°C, as specified in the process conditions.

[0040] Once the pressure inside the processing vessel 10 has stabilized at a predetermined level and the temperature inside the processing vessel 10 has stabilized at a predetermined level, monosilane gas is supplied into the processing vessel 10. The supply rate of the monosilane gas is set to a predetermined flow rate (e.g., 0.3 slm) within the range of 0.1 slm to 3 slm indicated as process conditions. The processing apparatus 1 may rotate the wafer boat 16 in conjunction with the supply of the monosilane gas. The processing apparatus 1 then performs the above film formation process over a predetermined processing time.

[0041] This allows the processing apparatus 1 to form a first amorphous silicon film (seed layer 121) having a uniform film thickness on the insulating film 110. When the processing apparatus 1 forms the seed layer 121 having a desired film thickness, the processing apparatus 1 ends the first film formation step S1. Note that the processing apparatus 1 continues to rotate the wafer boat 16 even after the first film formation step S1 is completed.

[0042] Next, the processing apparatus 1 performs a second film formation process S2. In the second film formation process S2, a film formation process is performed on each substrate 100 under the following process conditions. Process gas: silicon-containing gas Temperature inside the processing vessel 10: 450°C or higher and 530°C or lower Pressure inside the processing vessel 10: 5 Torr (≒ 1.3 kPa) or less Processing gas flow rate: 0.1 slm or more and 5 slm or less

[0043] The silicon-containing gas used in the second film-forming process S2 may be, for example, monosilane gas, higher-order silane gas, halogen-containing silicon gas, or a mixture of two or more of these. Examples of halogen-containing silicon gases include fluorine-containing silicon gases such as SiF, SiHF, SiH, F, and SiH; chlorine-containing silicon gases such as SiCl, SiHCl, SiH, Cl (DCS), and SiH; and bromine-containing gases such as SiBr, SiHBr, SiH, Br, and SiHBr. In this embodiment, monosilane gas is used as the silicon-containing gas used in the second film-forming process S2 because it has a high film-forming rate and is inexpensive.

[0044] When transitioning from the first film formation process S1 to the second film formation process S2, the processing apparatus 1 continues to rotate the wafer boat 16 while continuing to supply monosilane gas into the processing chamber 10. The processing apparatus 1 then adjusts the pressure inside the processing chamber 10 from the pressure in the first film formation process S1 to a predetermined pressure of 5 Torr or less, which is indicated as a process condition for the second film formation process S2. The processing apparatus 1 also controls the power supplied to the heating unit 50 to adjust the temperature inside the processing chamber 10 to a predetermined temperature (e.g., 470°C) in the process conditions of 450°C or higher and 530°C or lower.

[0045] Then, the processing apparatus 1 performs the film formation process of the second film formation process S2 for an arbitrary process time while the pressure inside the processing chamber 10 is stabilized at the pressure for the second film formation process S2 and the temperature inside the processing chamber 10 is stabilized at the temperature for the second film formation process S2. As a result, a bulk layer 122 that covers the seed layer 121 is formed. After the seed layer 121 is completely covered with the bulk layer 122, the supply of monosilane gas into the processing chamber 10 is stopped. Note that the processing apparatus 1 continues to rotate the wafer boat 16 even after the second film formation process S2 is completed.

[0046] Finally, the processing apparatus 1 performs the crystallization step S3. At this time, the processing apparatus 1 adjusts the inside of the processing container 10 to an inert gas atmosphere. The inert gas atmosphere may be, for example, a nitrogen atmosphere or an argon atmosphere. Alternatively, a reducing gas atmosphere such as a hydrogen atmosphere may be used instead of the inert gas atmosphere. In this embodiment, the crystallization step is performed in the same apparatus as the first film formation step S1 and the second film formation step S2, but this is not limiting and the crystallization step may be performed in a different apparatus.

[0047] The processing apparatus 1 also controls the power supplied to the heating unit 50 to adjust the temperature of the crystallization step S3. The temperature of the crystallization step S3 is preferably a predetermined temperature (e.g., 650°C) within the range of 550°C to 700°C. This allows the crystallization of the seed layer 121 and the bulk layer 122 to proceed. As described above, in this embodiment, the seed layer 121 is formed in a low-temperature, high-pressure environment, so that large silicon nuclei are generated in the seed layer 121, and the generated nuclei serve as starting points for crystallization of the bulk layer 122. This allows the formation of a polycrystalline silicon film with large grain sizes.

[0048] In particular, the film formation process of the first film formation step S1 according to this embodiment is effective for an insulating film 110 having a flat, continuous plane portion 111 along the surface of the substrate 100 and a recess 112 formed from the flat portion 111 in the thickness direction of the substrate 100, as shown in FIG. 5(A). Examples of the recess 112 in the insulating film 110 include a hole and a trench. In FIG. 5(A) (and FIG. 5(B) described later), TOP, MID1, MID2, MID3, and BTM, which are marked on the seed layer 121, 221 of the recess 112, indicate film thickness measurement positions set in the depth direction of the recess 112. TOP is a film thickness measurement position around the opening of the recess 112, BTM is a film thickness measurement position around the bottom of the recess 112, and MID1, MID2, and MID3 are film thickness measurement positions set at intervals from the TOP side toward the BTM.

[0049] The film formation process according to this embodiment forms a seed layer 121 on the insulating film 110 using monosilane gas, thereby achieving high coverage in covering the recess 112 as shown in Fig. 5(A) . In other words, the film formation method and the polycrystalline silicon film formation method described above make it possible to form the seed layer 121 with a uniform thickness on the inner surface of the recess 112 along the depth direction of the recess 112.

[0050] In contrast, in conventional film formation processes, as shown in Figure 5(B), a seed layer 221 is formed on the insulating film 210 using a higher silane gas such as disilane (Si2H6) gas. Disilane gas has difficulty penetrating deep into the recess 212 and exhibits low coverage in covering the recess 212. For this reason, disilane gas forms a thin seed layer 221 from the opening (TOP) side of the recess 212 toward the bottom (BTM).

[0051] Specifically, when the film thickness of the seed layer 121 formed in the recess 112 when the film formation process according to this embodiment is performed and the film thickness of the seed layer 221 formed in the recess 212 when the conventional film formation process is performed are compared, the results shown in FIG. 5(C) are obtained. In the graph of FIG. 5(C), TOP, MID1, MID2, MID3, and BTM on the horizontal axis correspond to TOP, MID1, MID2, MID3, and BTM in FIGS. 5(A) and 5(B). In addition, in the graph of FIG. 5(C), the vertical axis represents the ratio of the film thickness at each film thickness measurement position to the TOP of the recess 112, 212 (=film thickness rate).

[0052] 5(C), the seed layer 221 formed by the conventional film formation process had a BTM film thickness ratio of 67.9% to the TOP. This thin bottom film thickness may result in the bulk layer 222, which is stacked on the seed layer 221 in the next step, also being formed with an uneven film thickness.

[0053] In contrast, the seed layer 121 formed by the film formation process according to this embodiment had a film thickness rate of BTM to TOP of 97.7%. In other words, it can be said that the film formation process according to this embodiment can form a seed layer 121 with a more uniform film thickness on the inner surface of the recess 112 compared to conventional film formation processes. Due to the seed layer 121 with such a uniform film thickness, the bulk layer 122 formed in the second film formation step S2 is also formed with a uniform film thickness on the inner surface of the recess 112.

[0054] The coverage of the seed layer 121 formed by the film formation method according to this embodiment is superior to the coverage of the seed layer 221 formed by a conventional film formation process. Therefore, the film formation process according to this embodiment can make the film thickness of the seed layer 121 formed on the flat portion 111 more uniform than the film thickness of the seed layer 221 formed on the flat portion 211 by a conventional film formation process. Furthermore, the film formation method according to this embodiment is not limited to the formation of the seed layer 121, and may be applied to the formation of other films depending on the purpose, such as achieving uniform film thickness.

[0055] The technical ideas and effects of the present disclosure explained in the above embodiments will be described below.

[0056] A first aspect of the present disclosure is a film formation method for forming an amorphous silicon film (seed layer 121) on a substrate 100, in which monosilane (SiH4) gas is supplied into a processing vessel 10 containing the substrate 100, and the film formation process is performed under the following process conditions (a) and (b): (a) The temperature inside the processing vessel 10 is set in the range of 300° C. to 440° C. (b) The pressure inside the processing chamber 10 is set to a range of 10 Torr to 100 Torr.

[0057] According to the above, the film formation method supplies monosilane (SiH4) gas into the processing chamber 10 under a low-temperature, high-pressure environment. As a result, an amorphous silicon film having a uniform film thickness can be formed on the substrate 100. This makes it possible to improve the coverage of the seed layer 121, for example, if the amorphous silicon film to be formed is a seed layer 121 that serves as a nucleus on the interface side of the substrate 100. Furthermore, the film formation method can produce large grain sizes when the amorphous silicon film is crystallized.

[0058] The film forming process further includes the following process condition (c). (c) The flow rate of the monosilane (SiH4) gas supplied into the processing chamber 10 is set to a range of 0.1 slm or more and 3 slm or less.

[0059] As a result, the film formation method can stably supply monosilane gas into the processing chamber 10 even under the above process conditions (a) and (b), and can promote film formation on the substrate 100.

[0060] Furthermore, the substrate 100 has a flat, continuous plane portion 111 along the surface direction of the substrate 100, and in the film formation process, an amorphous silicon film (seed layer 121) is formed on the plane portion 111. As a result, the film formation method can form an amorphous silicon film having a uniform film thickness on the plane portion 111.

[0061] Furthermore, the substrate 100 has a recess 112 formed from the flat portion 111 along the thickness direction of the substrate 100, and in the film formation process, an amorphous silicon film (seed layer 121) is formed on the flat portion 111 and the recess 112. Even if the substrate 100 has the recess 112 in this way, the film formation method can form an amorphous silicon film (seed layer 121) of a uniform thickness on the inner surface of the recess 112 along the thickness direction of the substrate 100 by supplying monosilane gas in a low-temperature and high-pressure environment.

[0062] Furthermore, an insulating film 110 is formed on the substrate 100, and the amorphous silicon film (seed layer 121) is formed on the insulating film 110. This allows the film formation method to form an amorphous silicon film with a uniform film thickness on the insulating film 110.

[0063] Furthermore, a second aspect of the present disclosure includes a process for forming a first amorphous silicon film (seed layer 121) on substrate 100, a process for forming a second amorphous silicon film (bulk layer 122) covering the first amorphous silicon film, and a process for heating substrate 100. The process for forming the first amorphous silicon film on substrate 100 includes supplying monosilane (SiH4) gas into processing vessel 10 containing substrate 100, and performing a film formation process under the following process conditions (a) and (b): (a) The temperature inside the processing vessel 10 is set in the range of 300° C. to 440° C. (b) The pressure inside the processing chamber 10 is set to a range of 10 Torr to 100 Torr.

[0064] As a result, the method for forming a polycrystalline silicon film can form a first amorphous silicon film on the substrate 100 with a uniform film thickness.

[0065] Furthermore, the step of forming the second amorphous silicon film (bulk layer 122) is performed at a higher temperature and lower pressure than the step of forming the first amorphous silicon film (seed layer 121) on the substrate 100. This allows the bulk layer 122 to be efficiently formed on the seed layer 121, a method of forming a polycrystalline silicon film.

[0066] In addition, in the process of forming the second amorphous silicon film (bulk layer 122), monosilane (SiH4) gas is supplied into the processing chamber 10, and the film formation process is performed under the following process conditions (d) and (e). (d) The temperature inside the processing chamber 10 is set in the range of 450°C to 530°C. (e) Set the pressure inside the processing chamber 10 to 5 Torr or less.

[0067] As a result, the method for forming a polycrystalline silicon film can stably form a second amorphous silicon film having a desired film thickness on the first amorphous silicon film (seed layer 121).

[0068] The film forming method and polycrystalline silicon film forming method according to the presently disclosed embodiments are illustrative in all respects and are not limiting. The embodiments can be modified and improved in various ways without departing from the spirit and scope of the appended claims. The matters described in the above embodiments can be configured in other ways as long as they are not inconsistent, and can be combined as long as they are not inconsistent.

[0069] In the above embodiment, the processing apparatus is a batch type apparatus that processes multiple substrates at once, but the present disclosure is not limited to this. For example, the processing apparatus may be a single-wafer type apparatus that processes substrates one by one. [Explanation of symbols]

[0070] 10 Processing container 100 boards 121 seed layer 122 Bulk Layer S1 1st film formation process S2 2nd film formation process S3 Crystallization process

Claims

1. forming a first amorphous silicon film on a substrate; forming a second amorphous silicon film covering the first amorphous silicon film; and heating the substrate, The step of forming the first amorphous silicon film on the substrate includes: The processing vessel containing the substrate is filled with SiH ４ While supplying gas, a film formation process is performed under the following process conditions (a) and (b): The step of forming the second amorphous silicon film includes: performing a film formation process at a temperature higher than that and a pressure lower than that in the process of forming the first amorphous silicon film on the substrate; (a) setting the temperature inside the processing vessel in the range of 300° C. to 440° C. (b) setting the pressure in the processing vessel to a range of 10 Torr or more and 100 Torr or less; A method for forming a polycrystalline silicon film.

2. The step of forming the second amorphous silicon film includes: The processing chamber is filled with SiH ４ The gas is supplied and a film formation process is performed under the following process conditions (d) and (e). (d) setting the temperature inside the processing vessel in the range of 450° C. to 530° C. (e) Setting the pressure inside the processing vessel to 5 Torr or less 2. The method for forming a polycrystalline silicon film according to claim 1.

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