Film deposition method and film deposition apparatus

Abstract

To provide a technology that can improve the filling characteristics when filling a recess with a film.SOLUTION: A film deposition method includes the steps for: preparing a substrate having a recess; supplying an aminosilane to the substrate to form an inhibition layer on the surface of the recess; forming a silicon nitride film on the surface of the recess by performing a cycle a first number of times in which a silicon source material and a nitriding agent are supplied to the substrate non-simultaneously; and adjusting the ease with which the aminosilane adsorbs onto the surface of the recess, prior to the step for forming the inhibition layer.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a film formation method and a film formation apparatus. [Background technology]

[0002] A technique has been disclosed in which a recess formed in a substrate is filled with a silicon nitride film (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-139306 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a technique that can control the filling characteristics when filling a recess with a film. [Means for solving the problem]

[0005] A film forming method according to one embodiment of the present disclosure includes the steps of preparing a substrate having a recess, supplying an aminosilane to the substrate and forming an inhibitory layer on the surface of the recess, forming a silicon nitride film on the surface of the recess by performing a first cycle of non-simultaneously supplying a silicon raw material and a nitriding agent to the substrate, and adjusting the ease of adsorption of the aminosilane to the surface of the recess before the step of forming the inhibitory layer. [Effects of the Invention]

[0006] According to the present disclosure, it is possible to control the filling characteristics when filling a recess with a film. [Brief explanation of the drawings]

[0007] [Figure 1] 2 is a flowchart illustrating a film forming method according to an embodiment. [Figure 2] 1 is a cross-sectional view (1) showing a film forming method according to an embodiment. [Figure 3] FIG. 2 is a cross-sectional view (2) showing the film forming method according to the embodiment. [Figure 4] FIG. 3 is a cross-sectional view (3) showing the film forming method according to the embodiment. [Figure 5] FIG. 4 is a cross-sectional view (4) showing the film forming method according to the embodiment. [Figure 6] FIG. 5 is a cross-sectional view (5) showing the film forming method according to the embodiment. [Figure 7] 2 is a flowchart showing an example of an inhibition layer forming step S4 in FIG. 1. [Figure 8] 2 is a flowchart showing an example of a film forming step S6 in FIG. [Figure 9] 1 is a vertical cross-sectional view showing a film forming apparatus according to an embodiment. [Figure 10] 1 is a horizontal cross-sectional view showing a film forming apparatus according to an embodiment. [Figure 11] FIG. 1 is a diagram showing the relationship between the number of ALD cycles and the thickness of a silicon nitride film on a silicon film. [Figure 12] FIG. 10 is a diagram showing the relationship between the number of ALD cycles and the thickness of a silicon nitride film on a silicon oxide film. [Figure 13] FIG. 10 is a diagram showing the relationship between the number of ALD cycles and the thickness of a silicon nitride film on a silicon nitride film. DETAILED DESCRIPTION OF THE INVENTION

[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 reference numerals are used to designate the same or corresponding members or components, and redundant descriptions will be omitted.

[0009] [Film formation method] A film forming method according to an embodiment will be described with reference to Fig. 1 to Fig. 8. Fig. 1 is a flowchart showing the film forming method according to an embodiment. Figs. 2 to 6 are cross-sectional views showing the film forming method according to an embodiment. Fig. 7 is a flowchart showing an example of the inhibition layer forming step S4 in Fig. 1. Fig. 8 is a flowchart showing an example of the film forming step S6 in Fig. 1.

[0010] As shown in FIG. 1, the film forming method according to the embodiment includes a preparation step S2, a surface oxidation step S3, an inhibition layer formation step S4, a film forming step S6, and a determination step S8.

[0011] The preparation step S2 includes preparing a substrate 100, as shown in FIG. 2. The substrate 100 has a silicon nitride film 110 and a silicon film 120. The silicon nitride film 110 has a flat upper surface. The silicon film 120 is provided on the upper surface of the silicon nitride film 110. The silicon film 120 has a convex shape. The silicon film 120 is, for example, an amorphous silicon film. The silicon nitride film 110 and the silicon film 120 form a recess 130. The recess 130 has a bottom surface 131, side surfaces 132, and an upper surface 133. The silicon nitride film 110 forms the bottom surface 131. The silicon film 120 forms the side surfaces 132 and the upper surface 133.

[0012] The surface oxidation step S3 is performed after the preparation step S2. As shown in FIG. 3, the surface oxidation step S3 includes supplying oxygen (O2) to the substrate 100 to form an oxide layer 121 on the upper part of the recess 130. The oxide layer 121 has the property of increasing the ease of adsorption of aminosilane. Therefore, by performing the surface oxidation step S3, the ease of adsorption of aminosilane to the upper part of the recess 130 increases. The surface oxidation step S3 may also supply plasma generated from oxygen (hereinafter referred to as "oxygen plasma") to the substrate 100. Because oxygen plasma has a relatively short lifespan, it does not reach the depths of the recess 130 and tends to selectively form an oxide layer 121 on the upper part of the recess 130.

[0013] The inhibitor layer formation step S4 is performed after the surface oxidation step S3. As shown in FIG. 4, the inhibitor layer formation step S4 includes forming an inhibitor layer 140 on the side surface 132 of the recess 130, the inhibitor layer 140 being thicker at the upper portion than at the lower portion in the depth direction. The inhibitor layer 140 is formed from aminosilane. Aminosilane has the property of inhibiting the formation of the silicon nitride film 150. An example of the aminosilane is TMSDMA (trimethylsilyldimethylamine). The inhibitor layer formation step S4 may include not forming the inhibitor layer 140 on the bottom surface 131 of the recess 130. In this case, the formation of the silicon nitride film 150 on the bottom surface 131 can be promoted in the film formation step S6. The inhibitor layer formation step S4 may include forming the inhibitor layer 140 on the upper surface 133 of the recess 130. In this case, the formation of the silicon nitride film 150 on the upper surface 133 can be inhibited in the film formation step S6. The inhibition layer forming step S4 includes, for example, steps S41 and S42 shown in FIG.

[0014] Step S41 includes supplying aminosilane to the substrate 100. In step S41, the processing conditions for supplying aminosilane to the substrate 100 are adjusted so that more aminosilane is adsorbed to the upper portion of the side surface 132 of the recess 130 in the depth direction than to the lower portion. The processing conditions include the substrate temperature, processing pressure, and supply flow rate of aminosilane. In step S41, the oxide layer 121 is formed in the upper portion of the recess 130, which promotes adsorption of aminosilane to the upper portion of the recess 130. This increases the thickness of the inhibition layer 140 in the upper portion of the recess 130. As a result, the effect of inhibiting the formation of the silicon nitride film 150 in the upper portion of the recess 130 in the film formation step S6 is enhanced. In step S41, the substrate temperature is, for example, 300°C or higher and 630°C or lower, and the processing pressure is, for example, 0.001 Torr or higher and 10 Torr or lower.

[0015] Step S42 is performed after step S41. Step S42 includes purging the aminosilane remaining in the processing vessel in which the substrate 100 is accommodated.

[0016] The film forming step S6 is performed after the inhibition layer forming step S4. The film forming step S6 includes forming a silicon nitride film 150 by atomic layer deposition (ALD). In the film forming step S6, as shown in FIG. 5, the silicon nitride film 150 is formed thicker in the lower part of the recess 130 where the inhibition layer 140 is thinner. The film forming step S6 includes, for example, forming the silicon nitride film 150 in the recess 130 by performing a first ALD cycle in which a silicon source material and a nitriding agent are supplied non-simultaneously to the substrate 100. The silicon source material is, for example, dichlorosilane (DCS). The nitriding agent is, for example, ammonia (NH). The film forming step S6 is, for example, a thermal process that does not use plasma. In this case, the generation of impurities derived from aminosilane can be reduced. The film forming step S6 may also be a plasma process that uses plasma. The film forming step S6 includes, for example, steps S61 to S65 shown in FIG. 8.

[0017] Step S61 includes purging the nitriding agent remaining in the processing vessel in which the substrate 100 is accommodated.

[0018] Step S62 is performed after step S61. Step S62 includes supplying a silicon source material to the substrate 100. The silicon source material is less likely to be adsorbed to the surface where the inhibition layer 140 is formed thicker. Therefore, the silicon source material is more likely to be adsorbed to the lower part of the recess 130 where the inhibition layer 140 is thinner. In step S62, the substrate temperature is, for example, 300°C or higher and 630°C or lower.

[0019] Step S63 is performed after step S62 and includes purging the silicon source material remaining in the processing vessel in which the substrate 100 is accommodated.

[0020] Step S64 is performed after step S63. Step S64 includes supplying a nitriding agent to the substrate 100 to nitride the silicon raw material adsorbed on the surface of the recess 130.

[0021] Step S65 is performed after step S64. Step S65 includes determining whether steps S61 to S64 have been performed a first number of times. If the number of times has not reached the first number of times (NO in step S65), steps S61 to S64 are performed again. If the number of times has reached the first number of times (YES in step S65), the film forming process S6 is terminated. In this way, by repeating steps S61 to S65 until the number of times has reached the first number of times, a silicon nitride film 150 having a substantially V-shape can be formed in the recess 130, as shown in FIG. 5.

[0022] The determination step S8 is performed after the film-forming step S6. The determination step S8 includes determining whether the surface oxidation step S3, the inhibitor layer formation step S4, and the film-forming step S6 have been performed a second number of times. If the number of times has not reached the second number of times (NO in the determination step S8), the surface oxidation step S3, the inhibitor layer formation step S4, and the film-forming step S6 are performed again. If the number of times has reached the second number of times (YES in the determination step S8), the process ends. In this way, the surface oxidation step S3, the inhibitor layer formation step S4, and the film-forming step S6 are repeated in this order until the number of times has reached the second number of times. The second number of times is the number of times required to fill the recess 130 with the silicon nitride film 150, as shown in FIG. 6.

[0023] As described above, according to the film forming method of the embodiment, before forming the inhibition layer 140 in the recess 130, the oxide layer 121 is formed on the upper part of the recess 130. The oxide layer 121 promotes adsorption of aminosilane, so the inhibition layer 140 can be formed thicker in the upper part of the recess 130 than in the lower part. Therefore, in the film forming step S6, the silicon nitride film 150 can be formed thicker in the lower part of the recess 130 than in the upper part. As a result, the silicon nitride film 150 is formed from the bottom surface 131 toward the upper surface 133 of the recess 130, which reduces the occurrence of voids, seams, and the like in the recess 130. In other words, the filling characteristics when filling the recess 130 with the silicon nitride film 150 can be improved.

[0024] In the above embodiment, instead of the surface oxidation step S3, a surface nitriding step may be performed in which nitrogen (N2) is supplied to the substrate 100 to form a nitride layer on the upper part of the recess 130. The nitride layer has the property of reducing the ease of adsorption of aminosilane. Therefore, performing the surface nitriding step reduces the ease of adsorption of aminosilane to the upper part of the recess 130. The surface nitriding step may also be performed by supplying plasma generated from nitrogen (hereinafter referred to as "nitrogen plasma") to the substrate 100. Because nitrogen plasma has a relatively short lifespan, it does not reach the depths of the recess 130 and is likely to selectively form a nitride layer on the upper part of the recess 130. In this way, by performing the surface oxidation step S3 or the surface nitriding step before the inhibition layer formation step S4, the ease of adsorption of aminosilane to the surface of the recess 130 can be adjusted.

[0025] In the above embodiment, the surface oxidation step S3, the inhibition layer formation step S4, and the film formation step S6 may be repeated in this order, and then the surface nitriding step, the inhibition layer formation step S4, and the film formation step S6 may be repeated in this order. In other words, the surface oxidation step S3 may be changed to the surface nitriding step midway through the repetition. The surface oxidation step S3 is an example of a first process, and the surface nitriding step is an example of a second process.

[0026] [Film forming equipment] The film forming apparatus 1 according to the embodiment will be described with reference to Fig. 9 and Fig. 10. Fig. 9 is a vertical cross-sectional view showing the film forming apparatus 1 according to the embodiment. Fig. 10 is a horizontal cross-sectional view showing the film forming apparatus 1 according to the embodiment.

[0027] The film forming apparatus 1 is a batch type apparatus that processes a plurality of substrates W at once. The substrates W are, for example, semiconductor wafers. The film forming apparatus 1 includes a processing chamber 10, a gas supply unit 30, an exhaust unit 40, a heating unit 50, and a control unit 90.

[0028] The processing vessel 10 can have its interior depressurized. The processing vessel 10 accommodates a substrate W. The processing vessel 10 has an inner tube 11 and an outer tube 12. The inner tube 11 has a cylindrical shape with a ceiling and an open lower end. The outer tube 12 has a cylindrical shape with a ceiling and an open lower 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. The inner tube 11 and the outer tube 12 have a double-tube structure arranged coaxially.

[0029] A storage section 13 for storing a gas supply pipe is formed along the longitudinal direction (vertical direction) on the side wall of the inner pipe 11. For example, a part of the side wall of the inner pipe 11 is protruded outward to form a convex section 14, and the inside of the convex section 14 is formed as the storage section 13.

[0030] A rectangular opening 15 is formed along the longitudinal direction in the side wall of the inner tube 11. The opening 15 faces the storage portion 13.

[0031] 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 boat 16, or is formed so as to extend in the vertical direction and be longer than the length of the boat 16.

[0032] The lower end of the processing vessel 10 is supported by a cylindrical manifold 17. The manifold 17 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 tube 12. A seal member 19, such as an O-ring, is provided between the flange 18 and the lower end of the outer tube 12. This keeps the inside of the outer tube 12 airtight.

[0033] An annular support member 20 is provided on the inner wall of the upper portion of the manifold 17. The support member 20 supports the lower end of the inner tube 11. A lid member 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. This airtightly closes the opening at the lower end of the processing vessel 10, i.e., the opening of the manifold 17. The lid member 21 is made of, for example, stainless steel.

[0034] A rotating shaft 24 is provided in the center of the lid 21, penetrating through the lid 21 via a magnetic fluid seal 23. The lower part of the rotating shaft 24 is rotatably supported by an arm 25A of an elevation mechanism 25 made up of a boat elevator.

[0035] A rotating plate 26 is provided at the upper end of the rotating shaft 24. A boat 16 holding substrates W is placed on the rotating plate 26 via a quartz heat retention stand 27. The boat 16 rotates by rotating the rotating shaft 24. The boat 16 moves up and down integrally with the lid 21 by raising and lowering the lifting mechanism 25. This allows the boat 16 to be inserted into and removed from the processing vessel 10. The boat 16 can be accommodated within the processing vessel 10. The boat 16 holds multiple (e.g., 50 to 150) substrates W in a shelf-like manner. The boat 16 holds the multiple substrates W approximately horizontally with spacing between them in the vertical direction.

[0036] The gas supply unit 30 is configured to be able to introduce various process gases into the inner pipe 11. The gas supply unit 30 includes a TMSDMA supply unit 31, a DCS supply unit 32, an ammonia supply unit 33, and an oxygen supply unit .

[0037] TMSDMA supply unit 31 includes gas supply pipe 31a inside processing vessel 10 and supply flow path 31b outside processing vessel 10. Supply flow path 31b is provided with, in order from upstream to downstream in the gas flow direction, TMSDMA source 31c, mass flow controller 31d, and valve 31e. Thus, the supply timing of TMSDMA from TMSDMA source 31c is controlled by valve 31e, and the flow rate is adjusted to a predetermined value by mass flow controller 31d. TMSDMA flows from supply flow path 31b into gas supply pipe 31a and is then discharged from gas supply pipe 31a into processing vessel 10.

[0038] The DCS supply unit 32 includes a gas supply pipe 32a inside the processing vessel 10 and a supply flow path 32b outside the processing vessel 10. A DCS source 32c, a mass flow controller 32d, and a valve 32e are installed in supply flow path 32b, in that order from upstream to downstream in the gas flow direction. The supply timing of DCS from the DCS source 32c is controlled by the valve 32e, and the flow rate is adjusted to a predetermined value by the mass flow controller 32d. The DCS flows from supply flow path 32b into the gas supply pipe 32a and is then discharged from the gas supply pipe 32a into the processing vessel 10.

[0039] The ammonia supply unit 33 includes a gas supply pipe 33a inside the processing vessel 10 and a supply flow path 33b outside the processing vessel 10. An ammonia source 33c, a mass flow controller 33d, and a valve 33e are installed in the supply flow path 33b, in this order from upstream to downstream in the gas flow direction. Thus, the supply timing of ammonia from the ammonia source 33c is controlled by the valve 33e, and the flow rate is adjusted to a predetermined value by the mass flow controller 33d. The ammonia flows from the supply flow path 33b into the gas supply pipe 33a and is discharged from the gas supply pipe 33a into the processing vessel 10.

[0040] The oxygen supply unit 34 includes a gas supply pipe 34a inside the processing vessel 10 and a supply flow path 34b outside the processing vessel 10. The supply flow path 34b is provided with, in order from upstream to downstream in the gas flow direction, an oxygen source 34c, a mass flow controller 34d, a valve 34e, and a remote plasma source 34p. The valve 34e controls the supply timing of oxygen from the oxygen source 34c, and the mass flow controller 34d adjusts the flow rate to a predetermined value. Oxygen flows from the supply flow path 34b into the gas supply pipe 34a and is discharged from the gas supply pipe 34a into the processing vessel 10. The remote plasma source 34p generates plasma from the oxygen flowing through the supply flow path 34b. This allows plasma generated from oxygen to be supplied into the processing vessel 10 from the gas supply pipe 34a.

[0041] The gas supply pipes 31a, 32a, 33a, and 34a are fixed to the manifold 17. The gas supply pipes 31a, 32a, 33a, and 34a are made of, for example, quartz. The gas supply pipes 31a, 32a, 33a, and 34a extend linearly in the vertical direction near the inner pipe 11, and then bend in an L-shape within the manifold 17 and extend horizontally, thereby penetrating the manifold 17. The gas supply pipes 31a, 32a, 33a, and 34a are arranged side by side along the circumferential direction of the inner pipe 11 and are formed at the same height.

[0042] A plurality of discharge ports 31f, 32f, 33f, and 34f are provided in the gas supply pipes 31a, 32a, 33a, and 34a at positions within the inner pipe 11. The discharge ports 31f, 32f, 33f, and 34f are formed at predetermined intervals along the extension direction of the gas supply pipes 31a, 32a, 33a, and 34a. Each discharge port 31f, 32f, 33f, and 34f discharges gas horizontally toward the substrate W from the radially outer side of the substrate W. Each discharge port 31f, 32f, 33f, and 34f discharges gas parallel to the main surface of the substrate W. The intervals between the discharge ports are set to, for example, the same as the intervals between the substrates W held in the boat 16. The height position of each discharge port is set to, for example, the midpoint between vertically adjacent substrates W. In this case, each discharge port can efficiently supply gas to the opposing surfaces of adjacent substrates W.

[0043] The gas supply unit 30 may mix multiple types of gases and discharge the mixed gas from a single gas supply pipe. The gas supply pipes 31a, 32a, 33a, and 34a may have different shapes and arrangements. The gas supply unit 30 may further include a gas supply pipe that supplies another gas, such as an inert gas.

[0044] 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 flow path 42 is connected to the gas outlet 41. A pressure adjustment valve 43 and a vacuum pump 44 are sequentially disposed in the exhaust flow path 42, so that the inside of the processing chamber 10 can be exhausted.

[0045] The heating unit 50 is provided around the outer tube 12. The heating unit 50 is provided, 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 each substrate W in the processing vessel 10.

[0046] The control unit 90 is an electronic circuit such as a CPU (Central Processing Unit), FPGA (Field Programmable Gate Array), ASIC (Application Specific Integrated Circuit), etc. The control unit 90 executes various control operations described in this specification by executing instruction codes stored in a memory or by being a circuit designed for a specific application.

[0047] [Operation of the Film Forming Apparatus] The following describes the operation of the film forming apparatus 1 when the film forming method according to the embodiment is performed in the film forming apparatus 1. The operation of the film forming apparatus 1 shown below is performed under the control of the control unit 90.

[0048] First, the control unit 90 executes the preparation step S2. Specifically, the lifting mechanism 25 loads the boat 16 holding multiple substrates W into the processing vessel 10, and the lid 21 airtightly closes the opening at the bottom of the processing vessel 10. Next, the exhaust unit 40 reduces the pressure inside the processing vessel 10, and the heating unit 50 adjusts the temperature of the substrates W to a predetermined temperature (e.g., 630°C). Each substrate W may be the substrate 100 described above.

[0049] Next, the control unit 90 executes a surface oxidation step S3. Specifically, the gas supply unit 30 supplies oxygen plasma into the processing chamber 10, and an oxide layer 121 is formed on the upper part of the recess 130.

[0050] Next, the control unit 90 executes the inhibition layer formation step S4. Specifically, the gas supply unit 30 supplies TMSDMA into the processing chamber 10 to form an inhibition layer 140 on the side surface 132 of the recess 130, the inhibition layer 140 being thicker at the top than at the bottom in the depth direction. At this time, the oxide layer 121 formed at the top of the recess 130 promotes adsorption of aminosilane to the top of the recess 130. Therefore, the thickness of the inhibition layer 140 becomes thicker at the top of the recess 130. As a result, the effect of inhibiting the formation of the silicon nitride film 150 at the top of the recess 130 in the film formation step S6 is enhanced.

[0051] Next, the control unit 90 executes the film formation process S6. Specifically, the gas supply unit 30 performs a cycle of non-simultaneously supplying DCS and ammonia into the processing chamber 10 a first number of times to form the silicon nitride film 150 in the recess 130. At this time, since the inhibition layer 140 is formed thicker at the upper part of the side surface 132 of the recess 130 in the depth direction than at the lower part, the silicon nitride film 150 can be formed thicker at the lower part of the side surface 132 of the recess 130 in the depth direction than at the upper part. The first number of times is, for example, 10 times.

[0052] Next, the control unit 90 performs a determination step S8. Specifically, the control unit 90 determines whether the surface oxidation step S3, the inhibition layer formation step S4, and the film formation step S6 have been performed a second number of times. If the number of times has not reached the second number of times, the surface oxidation step S3, the inhibition layer formation step S4, and the film formation step S6 are performed again. If the number of times has reached the second number of times, the processing ends. In this way, the control unit 90 repeats the surface oxidation step S3, the inhibition layer formation step S4, and the film formation step S6 in this order until the number of times has reached the second number of times.

[0053] Next, the control unit 90 increases the pressure inside the processing vessel 10 to atmospheric pressure and decreases the temperature inside the processing vessel 10 to the unloading temperature, and then controls the lifting mechanism 25 to unload the boat 16 from the processing vessel 10 .

[0054] As described above, the film forming method according to the embodiment can be carried out in the film forming apparatus 1.

[0055] [Experimental results] First, substrates having different underlayers on their surfaces were prepared. The underlayers were a silicon film, a silicon oxide film, and a silicon nitride film. Next, the inhibitory layer formation step S4, the film formation step S6, and the evaluation step S8 were performed on each substrate in this order using the film formation apparatus 1, and the thickness of the silicon nitride film formed on each film was measured. Furthermore, the film formation step S6 and the evaluation step S8 were performed on each substrate in this order using the film formation apparatus 1 without performing the inhibitory layer formation step S4, and the thickness of the silicon nitride film formed on each film was measured.

[0056] In the inhibition layer formation step S4, the substrate temperature was set to 630°C, the treatment pressure was set to 66.7 Pa (0.5 Torr), the treatment time was set to 5 seconds or 30 seconds, and TMSDMA was used as the aminosilane. In the film formation step S6, the substrate temperature was set to 630°C, DCS was used as the silicon source, and ammonia was used as the nitriding agent. In the determination step S8, the number of ALD cycles in which DCS and ammonia were supplied non-simultaneously (hereinafter referred to as the "ALD cycle number") was set to 40, 50, 60, 70, 80, 90, or 100.

[0057] FIG. 11 shows the relationship between the number of ALD cycles and the thickness of a silicon nitride film on a silicon film. FIG. 12 shows the relationship between the number of ALD cycles and the thickness of a silicon nitride film on a silicon oxide film. FIG. 13 shows the relationship between the number of ALD cycles and the thickness of a silicon nitride film on a silicon nitride film. In FIGS. 11 to 13, the horizontal axis represents the number of ALD cycles (number of times), and the vertical axis represents the thickness (nm) of the silicon nitride film on each film. In FIGS. 11 to 13, circles represent results when the inhibition layer formation process S4, film formation process S6, and evaluation process S8 were performed in this order, with the processing time for the inhibition layer formation process S4 set to 5 seconds. Squares represent results when the inhibition layer formation process S4, film formation process S6, and evaluation process S8 were performed in this order, with the processing time for the inhibition layer formation process S4 set to 30 seconds. Triangles represent results when the film formation process S6 and evaluation process S8 were performed in this order without performing the inhibition layer formation process S4.

[0058] As shown in Figures 11 to 13, an approximate line (see the solid line in the figure) was determined for each condition, and the number of incubation cycles under each condition was calculated using the approximate line. The number of incubation cycles is the number of ALD cycles required from the start of the ALD cycles to the start of deposition of a silicon nitride film on the substrate. In Figures 11 to 13, the number of incubation cycles is the number of ALD cycles at the point where the approximate line intersects with the X-axis.

[0059] As shown by the circles in Figure 11, when the base was a silicon film, the number of incubation cycles was 31 when the inhibitory layer formation step S4 (processing time 5 seconds), the film formation step S6, and the evaluation step S8 were performed in this order. As shown by the squares in Figure 11, the number of incubation cycles was 36 when the inhibitory layer formation step S4 (processing time 30 seconds), the film formation step S6, and the evaluation step S8 were performed in this order. As shown by the triangles in Figure 11, the number of incubation cycles was 19 when the film formation step S6 and the evaluation step S8 were performed in this order without performing the inhibitory layer formation step S4. The results in Figure 11 indicate that when the base was a silicon film, the effect of TMSDMA in inhibiting the formation of a silicon nitride film was within the range of 12 to 17 ALD cycles.

[0060] As shown by the circles in Figure 12, when the base was a silicon oxide film, the number of incubation cycles was 61 when the inhibitory layer formation step S4 (processing time 5 seconds), the film formation step S6, and the evaluation step S8 were performed in this order. As shown by the squares in Figure 12, the number of incubation cycles was 69 when the inhibitory layer formation step S4 (processing time 30 seconds), the film formation step S6, and the evaluation step S8 were performed in this order. As shown by the triangles in Figure 12, the number of incubation cycles was 31 when the film formation step S6 and the evaluation step S8 were performed in this order without performing the inhibitory layer formation step S4. The results in Figure 12 indicate that when the base was a silicon oxide film, the effect of TMSDMA in inhibiting the formation of a silicon nitride film was within the range of 30 to 38 ALD cycles.

[0061] As shown by the circles in Figure 13, when the base was a silicon nitride film, the number of incubation cycles was 0 when the inhibitory layer formation step S4 (processing time 5 seconds), the film formation step S6, and the evaluation step S8 were performed in this order. As shown by the squares in Figure 13, the number of incubation cycles was 0 when the inhibitory layer formation step S4 (processing time 30 seconds), the film formation step S6, and the evaluation step S8 were performed in this order. As shown by the triangles in Figure 13, the number of incubation cycles was 0 when the film formation step S6 and the evaluation step S8 were performed in this order without performing the inhibitory layer formation step S4. The results in Figure 13 show that when the base was a silicon nitride film, the effect of TMSDMA inhibiting the formation of a silicon nitride film was equivalent to 0 ALD cycles.

[0062] From the results shown in Figures 11 to 13, it can be said that the effect of TMSDMA on inhibiting the formation of silicon nitride films is highest when the base is a silicon oxide film, second highest when the base is a silicon film, and lowest when the base is a silicon nitride film.

[0063] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive, and the above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims.

[0064] In the above embodiment, the aminosilane is TMSDMA, but the present disclosure is not limited thereto. The aminosilane may be TMSDMA, DIPAS (diisopropylaminosilane), 3DMAS (trisdimethylaminosilane), BTBAS (bistertialbutylaminosilane), or a combination thereof.

[0065] In the above embodiment, the silicon source is DCS, but the present disclosure is not limited thereto. The silicon source may be fluorine-containing silicon such as SiF, SiHF, SiHF, or SiHF, chlorine-containing silicon such as SiCl, SiHCl, SiHCl (DCS), SiHCl, or SiCl gas, or bromine-containing silicon such as SiBr, SiHBr, SiHBr, or SiHBr, or a combination thereof.

[0066] In the above embodiment, the nitriding agent is ammonia, but the present disclosure is not limited thereto. The nitriding agent may be ammonia, diazene (NH), hydrazine (NH), monomethylhydrazine (CH(NH)NH), or a combination thereof.

[0067] In the above embodiment, the film formation apparatus is described as a batch-type apparatus that processes multiple substrates at once, but the present disclosure is not limited to this. For example, the film formation apparatus may be a single-wafer-type apparatus that processes substrates one by one. For example, the film formation apparatus may be a semi-batch-type apparatus that processes the substrates by rotating a turntable on which multiple substrates are placed, causing each substrate to revolve and repeatedly pass through a process gas supply region arranged along the radial direction of the turntable. [Explanation of symbols]

[0068] 100 boards 110 Silicon nitride film 120 Silicone membrane 130 recess 140 Inhibitory layer 150 Silicon nitride film S2 preparation process S3 Surface oxidation process S4 Inhibition layer formation process S6 Film formation process S8 Judgment process

Claims

1. providing a substrate having a recess; supplying aminosilane to the substrate to form an inhibition layer on the surface of the recess; forming a silicon nitride film on the surface of the recess by performing a cycle of non-simultaneously supplying a silicon source material and a nitriding agent to the substrate a first number of times; a step of adjusting the ease with which the aminosilane is adsorbed onto the surface of the recessed portion before the step of forming the inhibition layer; The film forming method includes the steps of:

2. the step of adjusting the adsorption property, the step of forming the inhibition layer, and the step of forming the silicon nitride film are repeated in this order. The film forming method according to claim 1 .

3. the step of adjusting the adsorption property includes supplying oxygen to the substrate to form an oxide layer on the surface of the recess, thereby increasing the adsorption property of the aminosilane to the surface; The film forming method according to claim 2 .

4. the surface of the recess is the top of the recess; The film forming method according to claim 3 .

5. the step of adjusting the adsorption property includes supplying nitrogen to the substrate to form a nitride layer on the surface of the recess, thereby reducing the adsorption property of the aminosilane to the surface; The film forming method according to claim 2 .

6. the surface of the recess is the top of the recess; The film forming method according to claim 5 .

7. The step of adjusting the adsorption ease includes: a first treatment for supplying oxygen to the substrate to form an oxide layer on the surface of the recess, thereby increasing the ease with which the aminosilane is adsorbed onto the surface; a second treatment of supplying nitrogen to the substrate to form a nitride layer on the surface of the recess, thereby reducing the tendency of the aminosilane to be adsorbed onto the surface; Including, The repeating step includes changing from the first process to the second process during the repetition. The film forming method according to claim 2 .

8. The step of forming the silicon nitride film is a thermal process that does not use plasma. The film forming method according to claim 1 .

9. the aminosilane is trimethylsilyldimethylamine; the silicon source is dichlorosilane, The nitriding agent is ammonia. The film forming method according to claim 1 .

10. a processing vessel for accommodating a substrate; a gas supply unit that supplies a gas into the processing chamber; A control unit; Equipped with The control unit providing a substrate having a recess; supplying aminosilane to the substrate to form an inhibition layer on the surface of the recess; forming a silicon nitride film on the surface of the recess by performing a cycle of non-simultaneously supplying a silicon source material and a nitriding agent to the substrate a first number of times; a step of adjusting the ease with which the aminosilane is adsorbed onto the surface of the recessed portion before the step of forming the inhibition layer; configured to perform Film deposition equipment.

Images