Processing method and processing device

Abstract

A processing method according to one aspect of the present disclosure comprises: preparing a substrate comprising, on a surface thereof, a polycrystalline silicon film containing a catalyst metal; forming a gettering layer on the polycrystalline silicon film; and diffusing the catalyst metal contained in the polycrystalline silicon film into the gettering layer by annealing the substrate. The gettering layer is formed of amorphous silicon germanium containing an impurity that enables diffusion of the catalyst metal into the gettering layer.

Description

Processing method and processing apparatus

[0001] This disclosure relates to a processing method and an apparatus.

[0002] Patent Document 1 discloses a technique for forming a polycrystalline silicon film by a metal-induced crystallization method using nickel, and then removing the nickel remaining on the surface of the polycrystalline silicon film using oxygen radicals and hydrogen radicals.

[0003] Japanese Patent Application Publication No. 2011-60908

[0004] This disclosure provides a technology that allows for easy removal of the gettering layer.

[0005] A processing method according to one aspect of the present disclosure comprises: preparing a substrate having a polycrystalline silicon film containing a catalyst metal on its surface; forming a gettering layer on the polycrystalline silicon film; and diffusing the catalyst metal contained in the polycrystalline silicon film into the gettering layer by annealing the substrate, wherein the gettering layer is formed of amorphous silicon germanium containing impurities that enable the diffusion of the catalyst metal into the gettering layer.

[0006] According to this disclosure, the gettering layer can be easily removed.

[0007] This is a flowchart showing the processing method according to the embodiment. This is a cross-sectional view (1) showing the processing method according to the embodiment. This is a cross-sectional view (2) showing the processing method according to the embodiment. This is a cross-sectional view (3) showing the processing method according to the embodiment. This is a cross-sectional view (4) showing the processing method according to the embodiment. This is a cross-sectional view (5) showing the processing method according to the embodiment. This is a cross-sectional view (6) showing the processing method according to the embodiment. This is a cross-sectional view showing the processing apparatus according to the embodiment. This is a diagram showing the measurement results of nickel concentration. This is a diagram showing the measurement results of germanium concentration. This is a diagram showing the measurement results of phosphorus concentration. This is a diagram showing the measurement results of nickel concentration. This is a diagram showing the measurement results of etching amount.

[0008] Hereinafter, non-limiting exemplary embodiments of the present disclosure will be described with reference to the accompanying drawings. In all the accompanying drawings, the same or corresponding members or components are denoted by the same or corresponding reference numerals, and duplicate descriptions are omitted.

[0009] [Processing Method] Referring to FIGS. 1 to 7, the processing method according to the embodiment will be described. Hereinafter, the case of forming a polycrystalline silicon film on a substrate will be described as an example. The polycrystalline silicon film is used, for example, as a channel silicon film of a 3D NAND flash memory. FIG. 1 is a flowchart showing the processing method according to the embodiment. FIGS. 2 to 7 are cross-sectional views showing the processing method according to the embodiment. The processing method according to the embodiment has steps S1 to S6 shown in FIG. 1.

[0010] In step S1, as shown in FIG. 2, a substrate 100 is prepared. The substrate 100 has a silicon substrate 101 and an amorphous silicon film 102. The amorphous silicon film 102 is provided on the silicon substrate 101. The amorphous silicon film 102 can be formed, for example, by chemical vapor deposition (CVD) using a silicon-containing gas. The silicon-containing gas is, for example, diisopropylaminosilane (DIPAS) gas, disilane gas, monosilane gas, or a combination thereof.

[0011] In step S2, as shown in FIG. 3, a nickel source gas is supplied to the substrate 100 to diffuse nickel (Ni) into the amorphous silicon film 102. Nickel is an example of a catalyst metal. The nickel source gas can be generated, for example, by vaporizing a liquid nickel source or sublimating a solid nickel source. The nickel source may be an organic nickel source. The liquid nickel source is, for example, (EtCp) ５ , ５ , ５ Ni[Ni(C ２ H ５ C ５ H ４ ), ２ , or CpAllylNi[(C ３ H ５ )(C ５ H ５)Ni]. A solid nickel raw material is, for example, (MeCp) ２ Ni[Ni(CH ３ C ５ H ４ ) ２ ]. For example, if the nickel raw material is (EtCp) ２ In the case of Ni, the temperature of the substrate 100 when diffusing nickel into the amorphous silicon film 102 (hereinafter referred to as the "diffusion temperature") may be 150°C or higher and 300°C or lower.

[0012] In step S3, as shown in Figure 4, the substrate 100 is heated, and the amorphous silicon film 102 is crystallized by metal-induced crystallization with nickel as a nucleus in the amorphous silicon film 102 to form a polycrystalline silicon film 103. The temperature of the substrate 100 when forming the polycrystalline silicon film 103 (hereinafter referred to as the "crystallization temperature") may be 500°C or higher and 600°C or lower. The atmosphere when heating the substrate 100 is, for example, an inert gas atmosphere at atmospheric pressure. The atmosphere when heating the substrate 100 may also be a reduced pressure atmosphere.

[0013] In step S4, a gettering layer 104 is formed on the polycrystalline silicon film 103 as shown in Figure 5. The gettering layer 104 may be in contact with the polycrystalline silicon film 103. The gettering layer 104 is formed of amorphous silicon germanium containing impurities that allow nickel to diffuse into the gettering layer 104. The gettering layer 104 is formed of amorphous silicon germanium containing, for example, phosphorus (P). The impurities may be phosphorus (P), arsenic (As), boron (B), carbon (C), nitrogen (N), or a combination thereof. The amorphous silicon germanium may have a silicon (Si) content of 70 atm% to 80 atm% and a germanium (Ge) content of 20 atm% to 30 atm%. The gettering layer 104 can be formed, for example, by chemical vapor deposition using a silicon-containing gas, a germanium-containing gas, and a phosphorus-containing gas. In chemical vapor deposition, hydrogen gas may be further added. For example, the silicon-containing gas is monosilane (SiH). ４ ) is a gas. Silicon-containing gases include monosilane (SiH ４ ) gas, disilane (Si２ H ６ ) gas, trisilane (Si ３ H ８ ) gas, higher-order silanes with four or more silicon (Si) atoms, or combinations thereof may also be used. Germanium-containing gases include, for example, monogermanic (GeH) gases. ４ ) is a gas. Phosphorus-containing gases include, for example, phosphine (PH ３ ) gas. For example, if the silicon-containing gas is monosilane gas, the germanium-containing gas is monogermanic gas, and the phosphorus-containing gas is phosphine gas, the temperature of the substrate 100 when forming the gettering layer 104 (hereinafter referred to as the "gettering layer formation temperature") may be 400°C or higher and 500°C or lower.

[0014] In step S5, as shown in Figure 6, the substrate 100 is annealed to diffuse the nickel contained in the polycrystalline silicon film 103 into the gettering layer 104. The temperature of the substrate 100 when diffusing the nickel into the gettering layer 104 (hereinafter referred to as the "annealing temperature") may be 500°C or more and 900°C or less.

[0015] In step S6, as shown in Figure 7, the gettering layer 104 in which nickel has been diffused is supplied with an etching solution to selectively etch the gettering layer 104 from the polycrystalline silicon film 103. This removes the gettering layer 104 from the polycrystalline silicon film 103. As the etching solution, a processing solution that can selectively etch the gettering layer 104 from the polycrystalline silicon film 103 can be used. An example of the etching solution is SC1 (a mixed solution of ammonia water, hydrogen peroxide water, and water).

[0016] As a result, a polycrystalline silicon film 103 can be formed on the silicon substrate 101.

[0017] According to the processing method of the embodiment, the gettering layer 104 is formed of amorphous silicon germanium containing phosphorus. In this case, it is easy to obtain a selectivity ratio with the polycrystalline silicon film 103 when removing the gettering layer 104. Therefore, the gettering layer 104 can be easily removed.

[0018] The above embodiment describes the case in which a polycrystalline silicon film 103 is formed on a flat surface, but is not limited to this. For example, the processing method of the present disclosure can also be applied when forming a polycrystalline silicon film 103 on the inner surface of a recess such as a hole or trench. In this case, by diffusing nickel into the amorphous silicon film 102 using a nickel source gas, the variation in the amount of nickel diffusion in the depth direction of the recess can be reduced. As a result, a polycrystalline silicon film 103 with small particle size variation in the depth direction of the recess can be formed.

[0019] In the above embodiment, the case in which the gettering layer 104 is in contact with the polycrystalline silicon film 103 has been described, but the embodiment is not limited to this. A diffusion prevention layer may be provided between the gettering layer 104 and the polycrystalline silicon film 103 to prevent the diffusion of phosphorus from the gettering layer 104 to the polycrystalline silicon film 103. In other words, a diffusion prevention layer may be formed on the polycrystalline silicon film 103 before forming the gettering layer 104 on the polycrystalline silicon film 103. The diffusion prevention layer may be formed of undoped amorphous silicon or undoped amorphous germanium.

[0020] [Processing Apparatus] Referring to Figure 8, an example of a processing apparatus 1 capable of executing steps S2 to S5 of the processing method according to the embodiment will be described. Figure 8 is a cross-sectional view showing the processing apparatus 1 according to the embodiment.

[0021] The processing apparatus 1 comprises a processing container 10, a gas supply unit 30, an exhaust unit 40, a heating unit 50, and a control unit 90.

[0022] The processing container 10 has a double-tube structure consisting of a cylindrical inner tube 11 and a ceiling-covered outer tube 12 concentrically placed outside the inner tube 11. The inner tube 11 and outer tube 12 are made of, for example, quartz. The processing container 10 is configured to accommodate a boat 16.

[0023] A housing section 13 is formed on one side of the inner pipe 11 along its longitudinal direction (vertical direction). The housing section 13 is a region within a protrusion 14 formed by making a part of the side wall of the inner pipe 11 protrude outward. The supply pipes 31a, 32a, 33a, and 34a, which will be described later, are housed in the housing section 13.

[0024] The lower end of the processing container 10 is supported by a cylindrical manifold 17, which is made of, for example, stainless steel. A flange 18 is formed at the upper end of the manifold 17. The flange 18 supports the lower end of the outer pipe 12. A sealing member 19, such as an O-ring, is provided between the flange 18 and the lower end of the outer pipe 12.

[0025] An annular support portion 20 is provided on the upper inner wall of the manifold 17. The support portion 20 supports the lower end of the inner pipe 11. An exhaust port 21 is provided on the upper side wall of the manifold 17, above the support portion 20. A cover 22 is airtightly attached to the opening at the lower end of the manifold 17 via a sealing member 23 such as an O-ring. The cover 22 is made of, for example, stainless steel.

[0026] A rotating shaft 25 is provided through the center of the lid 22 via a magnetic fluid seal 24. The lower end of the rotating shaft 25 is rotatably supported by an arm 26A of a lifting mechanism 26 consisting of a boat elevator. A rotating plate 27 is provided at the upper end of the rotating shaft 25. The boat 16 is placed on the rotating plate 27 via a quartz insulation cylinder 28.

[0027] The boat 16 holds multiple substrates W (for example, 25 to 200) in a substantially horizontal position with vertical spacing between them. The substrates W are, for example, semiconductor wafers. The boat 16 rotates integrally with the rotation axis 25. The boat 16 moves up and down integrally with the lid 22 by raising and lowering the arm 26A, and is inserted into and removed from the processing container 10.

[0028] The gas supply unit 30 is configured to allow various gases to be introduced into the inner tube 11. The various gases include gases used in the film formation method according to the embodiment. The gas supply unit 30 includes a silicon raw material supply unit 31, a nickel raw material supply unit 32, a germanium raw material supply unit 33, and a phosphorus raw material supply unit 34.

[0029] The silicon raw material supply unit 31 includes a supply pipe 31a inside the processing container 10 and a supply path 31b outside the processing container 10. In the supply path 31b, a silicon raw material source 31c, a mass flow controller 31d, and an on-off valve 31e are provided in order from the upstream side to the downstream side in the gas flow direction. The silicon-containing gas from the silicon raw material source 31c is controlled in supply timing by the on-off valve 31e and adjusted to a predetermined flow rate by the mass flow controller 31d. The silicon-containing gas flows from the supply path 31b into the supply pipe 31a and is discharged from the supply pipe 31a into the processing container 10.

[0030] The nickel raw material supply unit 32 includes a supply pipe 32a inside the processing container 10 and a supply path 32b outside the processing container 10. In the supply path 32b, a raw material tank 32c, a regulating valve 32d, and an on-off valve 32e are provided in order from the upstream side to the downstream side in the gas flow direction. The raw material tank 32c stores the nickel raw material. The nickel raw material is a raw material that is liquid at room temperature or a raw material that is solid at room temperature. A heater 32f is provided around the raw material tank 32c. The heater 32f heats the nickel raw material in the raw material tank 32c. Thereby, the liquid nickel raw material is vaporized or the solid nickel raw material is sublimated to generate a nickel raw material gas.

[0031] The nickel raw material supply unit 32 has a carrier gas pipe 32g inserted into the raw material tank 32c from above. In the carrier gas pipe 32g, a carrier gas source 32h, an on-off valve 32i, and a regulating valve 32j are provided in order from the upstream side to the downstream side in the gas flow direction. Thereby, the carrier gas from the carrier gas source 32h is controlled in supply timing by the on-off valve 32i and adjusted to a predetermined flow rate by the regulating valve 32j, and is supplied into the raw material tank 32c. The carrier gas, together with the nickel raw material gas in the raw material tank 32c, is controlled in supply timing by the on-off valve 32e and adjusted to a predetermined flow rate by the regulating valve 32d, and flows from the supply path 32b into the supply pipe 32a. The nickel raw material gas and the carrier gas that have flowed into the supply pipe 32a are discharged from the supply pipe 32a into the processing container 10.

[0032] A bypass path 32k may be provided to connect the upstream side of the on-off valve 32i in the carrier gas pipe 32g and the downstream side of the on-off valve 32e in the supply path 32b. A bypass valve 32l may be provided in the bypass path 32k.

[0033] The germanium raw material supply unit 33 includes a supply pipe 33a in the processing vessel 10 and a supply path 33b outside the processing vessel 10. In the supply path 33b, a germanium raw material source 33c, a mass flow controller 33d, and an on-off valve 33e are provided in order from the upstream side to the downstream side in the gas flow direction. The germanium-containing gas from the germanium raw material source 33c is controlled in supply timing by the on-off valve 33e and adjusted to a predetermined flow rate by the mass flow controller 33d. The germanium-containing gas flows from the supply path 33b into the supply pipe 33a and is discharged from the supply pipe 33a into the processing vessel 10.

[0034] The phosphorus raw material supply unit 34 includes a supply pipe 34a in the processing vessel 10 and a supply path 34b outside the processing vessel 10. In the supply path 34b, a phosphorus raw material source 34c, a mass flow controller 34d, and an on-off valve 34e are provided in order from the upstream side to the downstream side in the gas flow direction. The phosphorus-containing gas from the phosphorus raw material source 34c is controlled in supply timing by the on-off valve 34e and adjusted to a predetermined flow rate by the mass flow controller 34d. The phosphorus-containing gas flows from the supply path 34b into the supply pipe 34a and is discharged from the supply pipe 34a into the processing vessel 10.

[0035] The supply pipes 31a, 32a, 33a, 34a are fixed to the manifold 17. The supply pipes 31a, 32a, 33a, 34a are formed of, for example, quartz. The supply pipes 31a, 32a, 33a, 34a extend linearly along the vertical direction in the vicinity of the inner pipe 11 and penetrate the manifold 17 by bending in an L shape and extending in the horizontal direction within the manifold 17. The supply pipes 31a, 32a, 33a, 34a are arranged side by side along the circumferential direction of the inner pipe 11 and are formed at the same height as each other.

[0036] Multiple gas holes 31p, 32p, 33p, and 34p are provided in the supply pipes 31a, 32a, 33a, and 34a, respectively, at the locations within the inner pipe 11. The gas holes 31p, 32p, 33p, and 34p are formed at predetermined intervals along the extending direction of each supply pipe 31a, 32a, 33a, and 34a. The gas holes 31p, 32p, 33p, and 34p release gas horizontally. The spacing between the gas holes 31p, 32p, 33p, and 34p is set to be the same as, for example, the spacing between the substrates W held in the boat 16. The height position of the gas holes 31p, 32p, 33p, and 34p is set to be at an intermediate position between adjacent substrates W in the vertical direction. In this case, the gas holes 31p, 32p, 33p, and 34p can efficiently supply gas to the opposing surfaces between adjacent substrates W.

[0037] The gas supply unit 30 may mix multiple types of gases and discharge the mixed gas from a single supply pipe. For example, supply pipes 31a, 32a, 33a, and 34a may be configured to discharge inert gas. For example, instead of providing supply pipe 33a, supply pipe 31a may be configured to discharge germanium-containing gas. For example, instead of providing supply pipe 34a, supply pipe 31a may be configured to discharge phosphorus-containing gas. The supply pipes 31a, 32a, 33a, and 34a may have different shapes and arrangements from each other. In addition to silicon-containing gas, nickel raw material gas, germanium-containing gas, and phosphorus-containing gas, the gas supply unit 30 may further have supply pipes for supplying other gases.

[0038] The exhaust section 40 includes an exhaust passage 41, a pressure regulating valve 42, and a vacuum pump 43. The exhaust passage 41 is connected to the exhaust port 21. The pressure regulating valve 42 and the vacuum pump 43 are located in the middle of the exhaust passage 41. The vacuum pump 43 is located downstream of the pressure regulating valve 42 in the gas flow direction. The gas inside the processing container 10 is discharged outside the processing container 10 by the vacuum pump 43, with the exhaust flow rate controlled by the pressure regulating valve 42.

[0039] The heating section 50 has a cylindrical shape and is provided around the outer tube 12. The heating section 50 heats each substrate W inside the processing container 10. The heating section 50 includes, for example, a heater.

[0040] The control unit 90 is an electronic circuit such as a CPU (Central Processing Unit), FPGA (Field Programmable Gate Array), or ASIC (Application Specific Integrated Circuit). The control unit 90 performs various control operations described in this specification by executing instruction codes stored in memory or by circuit design for special applications.

[0041] [Operation of the Processing Device] The operation of the processing device 1 when steps S2 to S5 of the processing method according to the embodiment are carried out will be described below. Step S6 may be performed by a device other than the processing device 1.

[0042] First, the control unit 90 controls the lifting mechanism 26 to move the boat 16 holding the multiple substrates W into the processing container 10, and then seals the opening at the lower end of the processing container 10 airtight with the lid 22. Each substrate W is, for example, a substrate 100 prepared in step S1.

[0043] Next, the control unit 90 controls the gas supply unit 30, the exhaust unit 40, and the heating unit 50 to execute step S2. Specifically, first, the control unit 90 controls the exhaust unit 40 to adjust the pressure inside the processing container 10 to a predetermined level, and controls the heating unit 50 to adjust and maintain the temperature of the substrate W at the diffusion temperature. Then, the control unit 90 controls the gas supply unit 30 to supply nickel raw material gas into the processing container 10. This causes nickel to diffuse into the amorphous silicon film 102.

[0044] Next, the control unit 90 controls the gas supply unit 30, the exhaust unit 40, and the heating unit 50 to execute step S3. Specifically, first, the control unit 90 controls the gas supply unit 30 to supply an inert gas such as nitrogen gas into the processing container 10, controls the exhaust unit 40 to adjust the pressure inside the processing container 10 to a predetermined level, and controls the heating unit 50 to adjust and maintain the temperature of the substrate W at the crystallization temperature. As a result, the amorphous silicon film 102 crystallizes due to metal-induced crystallization, forming a polycrystalline silicon film 103.

[0045] Next, the control unit 90 controls the gas supply unit 30, the exhaust unit 40, and the heating unit 50 to execute step S4. Specifically, first, the control unit 90 controls the exhaust unit 40 to adjust the pressure inside the processing container 10 to a predetermined level, and controls the heating unit 50 to adjust and maintain the temperature of the substrate W at the gettering layer formation temperature. Then, the control unit 90 controls the gas supply unit 30 to supply silicon-containing gas, germanium-containing gas, and phosphorus-containing gas into the processing container 10. As a result, a gettering layer 104 is formed on the polycrystalline silicon film 103.

[0046] Next, the control unit 90 controls the gas supply unit 30, the exhaust unit 40, and the heating unit 50 to execute step S5. Specifically, first, the control unit 90 controls the gas supply unit 30 to supply an inert gas such as nitrogen gas into the processing container 10, controls the exhaust unit 40 to adjust the pressure inside the processing container 10 to a predetermined level, and controls the heating unit 50 to adjust and maintain the temperature of the substrate W at the annealing temperature. As a result, nickel contained in the polycrystalline silicon film 103 diffuses into the gettering layer 104.

[0047] Next, the control unit 90 increases the pressure inside the processing container 10 to atmospheric pressure, then lowers the temperature inside the processing container 10 to the discharge temperature, and then controls the lifting mechanism 26 to discharge the boat 16 from inside the processing container 10.

[0048] As described above, steps S2 to S5 of the processing method according to the embodiment are completed in the processing apparatus 1.

[0049] [Examples] (Example 1) In Example 1, first, a substrate having a nickel-containing polycrystalline silicon film on its surface was prepared. Next, in the processing apparatus 1, a diffusion barrier layer formed of undoped amorphous silicon was formed on the polycrystalline silicon film. Next, in the processing apparatus 1, while maintaining the substrate temperature at 420°C, a gettering layer formed of phosphorus-containing amorphous silicon germanium was formed on the diffusion barrier layer by chemical vapor deposition using monosilane gas, monogermanic gas, and phosphine gas. Next, in the processing apparatus 1, the substrate was annealed in a nitrogen atmosphere. The annealing temperature was set to 600°C, 700°C, 800°C, or 0°C (no treatment). Next, the nickel concentration, germanium concentration, and phosphorus concentration in the polycrystalline silicon film, diffusion barrier layer, and gettering layer were measured by secondary ion mass spectrometry (SIMS).

[0050] Figure 9 shows the results of nickel concentration measurement. Figure 10 shows the results of germanium concentration measurement. Figure 11 shows the results of phosphorus concentration measurement. In Figures 9, 10, and 11, the horizontal axis represents the depth from the surface of the gettering layer [nm]. In Figure 9, the vertical axis represents the nickel (Ni) concentration [atoms / cm³]. ３ The vertical axis in Figure 10 represents the germanium (Ge) concentration [atoms / cm³]. ３ The vertical axis in Figure 11 represents the phosphorus (P) concentration [atoms / cm³]. ３ This shows the results. In Figures 9, 10, and 11, the solid line shows the result without annealing, the dashed line shows the result with an annealing temperature of 600°C, the dashed line shows the result with an annealing temperature of 700°C, and the dashed line shows the result with an annealing temperature of 800°C.

[0051] As shown in Figure 9, when the annealing temperature is 700°C and 800°C, the nickel concentration in the polycrystalline silicon film is lower and the nickel concentration in the gettering layer is higher compared to when no annealing treatment is performed. From these results, it can be said that when using a gettering layer formed of amorphous silicon germanium containing phosphorus, the nickel contained in the polycrystalline silicon film can be diffused into the gettering layer by setting the annealing temperature to 700°C and 800°C. When the annealing temperature is 700°C, the nickel concentration in the diffusion prevention layer is lower compared to when the annealing temperature is 800°C. From these results, it can be said that when the annealing temperature is 700°C, the efficiency of diffusing the nickel contained in the polycrystalline silicon film into the gettering layer is particularly high.

[0052] As shown in Figure 10, the germanium concentration in the polycrystalline silicon film is similar to that of the unannealed case when the annealing temperature is 600°C and 700°C, but higher when the annealing temperature is 800°C. From this result, it is considered that germanium diffuses from the gettering layer into the polycrystalline silicon film when the annealing temperature is 800°C. For this reason, from the viewpoint of reducing the diffusion of germanium from the gettering layer into the polycrystalline silicon film, an annealing temperature of 700°C or lower is preferable.

[0053] As shown in Figure 11, the phosphorus concentration in the polycrystalline silicon film is similar to that of the unannealed case when the annealing temperature is 600°C and 700°C, but higher when the annealing temperature is 800°C. From this result, it is considered that when the annealing temperature is 800°C, phosphorus diffuses from the gettering layer into the polycrystalline silicon film. Therefore, from the viewpoint of reducing the diffusion of phosphorus from the gettering layer into the polycrystalline silicon film, an annealing temperature of 700°C or lower is preferable.

[0054] (Comparative Example 1) In Comparative Example 1, the same process as in Example 1 was performed, except that a gettering layer formed of undoped amorphous silicon germanium was used instead of amorphous silicon germanium containing phosphorus. Specifically, first, a substrate having a polycrystalline silicon film containing nickel on its surface was prepared. Next, in the processing apparatus 1, a diffusion barrier layer formed of undoped amorphous silicon was formed on the polycrystalline silicon film. Next, in the processing apparatus 1, while maintaining the substrate temperature at 420°C, a gettering layer formed of undoped amorphous silicon germanium was formed on the diffusion barrier layer by chemical vapor deposition using monosilane gas, monogermanic gas, and phosphine gas. Next, in the processing apparatus 1, the substrate was annealed in a nitrogen atmosphere. The annealing temperature was 600°C, 700°C, 800°C, or 0°C (no treatment). Next, the nickel concentration, germanium concentration, and phosphorus concentration in the polycrystalline silicon film, diffusion barrier layer, and gettering layer were measured by secondary ion mass spectrometry.

[0055] Figure 12 shows the results of nickel concentration measurement. In Figure 12, the horizontal axis represents the depth from the surface of the gettering layer [nm], and the vertical axis represents the nickel (Ni) concentration [atoms / cm³]. ３ This shows the results. In Figure 12, the solid line shows the results without annealing, the dashed line shows the results with an annealing temperature of 600°C, the dashed line shows the results with an annealing temperature of 700°C, and the dashed line shows the results with an annealing temperature of 800°C.

[0056] As shown in Figure 12, the nickel concentration in the polycrystalline silicon film is similar to that of the unannealed film, regardless of whether the annealing temperature is 600°C, 700°C, or 800°C. From this result, it can be said that when the gettering layer is formed from undoped amorphous silicon germanium, the nickel contained in the polycrystalline silicon film hardly diffuses into the gettering layer.

[0057] (Example 2) In Example 2, first, a substrate having an amorphous silicon germanium film containing phosphorus on its surface and a substrate having an undoped polycrystalline silicon film on its surface were prepared. Next, SC1 was supplied to each substrate, and the relationship between the supply time of SC1 and the etching amount of each film was measured.

[0058] Figure 13 shows the measurement results of the etching amount. In Figure 13, the horizontal axis represents the supply time of SC1 [min], and the vertical axis represents the etching amount [nm] of each film. In Figure 13, circles indicate the etching amount of amorphous silicon germanium film containing phosphorus, and diamonds indicate the etching amount of undoped polycrystalline silicon film. In Figure 13, the dashed line L1 is an approximate straight line obtained by linearly approximating each point showing the measurement results of the etching amount of the silicon germanium film containing phosphorus, and the dashed line L2 is an approximate straight line obtained by linearly approximating each point showing the measurement results of the etching amount of the undoped polycrystalline silicon film.

[0059] As shown in Figure 13, the etching rate of the amorphous silicon germanium film containing phosphorus was approximately 0.38 nm / min, while the etching rate of the undoped polycrystalline silicon film was 0.02 nm / min. From these results, it can be said that by using SC1, the gettering layer 104 can be selectively etched and removed from the polycrystalline silicon film 103 in step S6 of the processing method according to the embodiment described above.

[0060] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The above embodiments may be omitted, replaced, or modified in various ways without departing from the scope and spirit of the appended claims.

[0061] The above embodiments describe the case where the catalyst metal is nickel, but the disclosure is not limited thereto. For example, the catalyst metal may be iron (Fe), copper (Cu), chromium (Cr), cobalt (Co), or silver (Ag).

[0062] In the embodiments described above, the processing apparatus is a batch-type apparatus that processes multiple substrates at once, but the disclosure is not limited thereto. For example, the processing apparatus may be a single-wafer apparatus that processes substrates one at a time.

[0063] This international application claims priority based on Japanese Patent Application No. 2024-227744, filed on 24 December 2024, and the entire contents of said application are incorporated herein by reference.

[0064] 100 Substrate 103 Polycrystalline silicon film 104 Gettering layer

Claims

1. A processing method comprising: preparing a substrate having a polycrystalline silicon film containing a catalytic metal on its surface; forming a gettering layer on the polycrystalline silicon film; and annealing the substrate to diffuse the catalytic metal contained in the polycrystalline silicon film into the gettering layer, wherein the gettering layer is formed of amorphous silicon germanium containing impurities that enable the diffusion of the catalytic metal into the gettering layer.

2. The processing method according to claim 1, wherein the gettering layer is formed by chemical vapor deposition using a silicon-containing gas, a germanium-containing gas, and a phosphorus-containing gas.

3. The processing method according to claim 2, wherein the silicon-containing gas is monosilane gas, the germanium-containing gas is monogermanic gas, and the phosphorus-containing gas is phosphine gas.

4. The processing method according to claim 1, wherein the polycrystalline silicon film is formed by crystallizing an amorphous silicon film by metal-induced crystallization with the catalyst metal as a nucleus.

5. The processing method according to claim 1, comprising supplying an etching solution to the gettering layer in which the catalyst metal has diffused to remove it.

6. The processing method according to any one of claims 1 to 5, wherein the formation of the gettering layer and the diffusion of the catalyst metal into the gettering layer are performed in the same processing vessel.

7. The treatment method according to any one of claims 1 to 5, wherein the catalyst metal is nickel.

8. The processing method according to any one of claims 1 to 5, wherein a recess is formed on the surface of the substrate, and the polycrystalline silicon film is formed on the inner surface of the recess.

9. The processing method according to any one of claims 1 to 5, comprising forming a diffusion prevention layer on the polycrystalline silicon film before forming the gettering layer on the polycrystalline silicon film, wherein the diffusion prevention layer is formed of amorphous silicon or amorphous silicon germanium.

10. A processing apparatus comprising: a processing container for housing a substrate; a gas supply unit for supplying gas into the processing container; a heating unit for the substrate housed in the processing container; and a control unit, wherein the control unit is configured to control the gas supply unit and the heating unit to perform the following: preparing a substrate having a polycrystalline silicon film containing a catalyst metal on its surface; forming a gettering layer on the polycrystalline silicon film; and diffusing the catalyst metal contained in the polycrystalline silicon film into the gettering layer by annealing the substrate, and the gettering layer is formed of amorphous silicon germanium containing impurities that enable the diffusion of the catalyst metal into the gettering layer.

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