Manufacturing method for nitrogen-doped silicon substrates

Abstract

This invention provides a method for manufacturing nitrogen-doped silicon substrates. [Solution] The present invention provides a method for manufacturing a nitrogen-doped silicon substrate, in which a base substrate including a central portion and an edge portion is formed by doping the edge portion with nitrogen to improve the mechanical stability of the base substrate.

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a nitrogen-doped silicon substrate, and more specifically, to a method for manufacturing a silicon substrate in which nitrogen is doped at the edges. [Background technology]

[0002] Silicon wafers used in semiconductor manufacturing processes for electronic components are obtained by growing an ingot and then slicing it. If the wafer strength is low, cracks may occur at the edges during the grinding process, and research is being conducted to improve the mechanical stability of the wafer.

[0003] While wafers sliced ​​from nitrogen-doped silicon crystals are known to contribute to increased wafer strength, the nitrogen doping across the entire wafer may affect subsequently formed devices. [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] The problem that this invention aims to solve is to provide a method for manufacturing nitrogen-doped silicon substrates with improved mechanical stability and electrical reliability.

[0005] Furthermore, the problems that this invention aims to solve are not limited to those mentioned above, and other problems will be apparent to those skilled in the art from the following description. [Means for solving the problem]

[0006] A method for manufacturing a nitrogen-doped silicon substrate according to one aspect of the present invention, made to solve the above-mentioned problems, comprises the steps of: preparing a circular base substrate including a central portion, an inner edge portion surrounding the central portion in a ring shape, an outer edge portion surrounding the inner edge portion in a ring shape, and including a first surface and a second surface facing the first surface; placing a first mask on the first surface of the base substrate that covers the central portion and the inner edge portion; a primary doping step of doping nitrogen on the first surface of the base substrate on the outer edge portion not covered by the first mask; and the first The method includes the steps of removing a mask and placing a second mask covering the central portion on the first surface of the base substrate; a secondary doping step of doping nitrogen onto the outer edge portion and the inner edge portion not covered by the second mask on the first surface of the base substrate; and the step of removing the second mask, wherein the atomic concentration of nitrogen contained in the inner edge portion is constant as a first concentration, the atomic concentration of nitrogen contained in the outer edge portion is constant as a second concentration, and the atomic concentration of nitrogen changes discontinuously at the boundary between the outer edge portion and the inner edge portion.

[0007] To solve the above-mentioned problems, another aspect of the present invention provides a method for manufacturing a nitrogen-doped silicon substrate, comprising an ingot manufacturing apparatus including a cylindrical mold and a nitrogen powder injection channel surrounding the mold in a ring shape, the method comprising: injecting silicon powder into the mold and injecting nitride powder into the nitrogen powder injection channel; applying a predetermined pressure to the silicon powder to form a silicon powder mass compressed into a polycrystalline state; applying heat to the silicon powder mass to recrystallize the silicon powder mass into a single-crystal structure; forming an ingot from the silicon powder mass; and slicing the ingot to form individual substrates, wherein in the recrystallization step, nitrogen is doped onto the side surface of the ingot by the nitride powder introduced through the nitrogen powder injection channel.

[0008] A further embodiment of the present invention, made to solve the above-mentioned problems, is a method for manufacturing a nitrogen-doped silicon substrate, comprising an ingot manufacturing apparatus including a cylindrical mold and a nitrogen coating portion surrounding the mold in a ring shape, the method comprising the steps of: forming a polycrystalline silicon rod in the mold; heating the side surface of the polycrystalline silicon rod placed in the mold with the nitrogen coating portion; doping the side surface of the polycrystalline silicon rod with a nitride-based material; recrystallizing the polycrystalline silicon rod into an ingot; and slicing the ingot to form individual substrates, wherein each of the individual substrates includes a nitrogen-doped region formed in a ring shape at its edge. [Effects of the Invention]

[0009] According to the present invention, it is possible to manufacture a silicon substrate with improved edge strength without affecting the electrical characteristics of the element. [Brief explanation of the drawing]

[0010] [Figure 1A] This figure shows a simplified representation of a nitrogen-doped silicon substrate according to one embodiment of the present invention. [Figure 1B] Figure 1A is a graph showing the nitrogen concentration in a nitrogen-doped silicon substrate. [Figure 2A] This figure shows a simplified representation of a nitrogen-doped silicon substrate according to one embodiment of the present invention. [Figure 2B] Figure 2A is a graph showing the nitrogen concentration in nitrogen-doped silicon substrates. [Figure 3A] This figure shows, in order, a method for manufacturing a nitrogen-doped silicon substrate according to one embodiment of the present invention. [Figure 3B] This figure shows, in order, a method for manufacturing a nitrogen-doped silicon substrate according to one embodiment of the present invention. [Figure 3C] This figure shows, in order, a method for manufacturing a nitrogen-doped silicon substrate according to one embodiment of the present invention. [Figure 3D]It is a diagram showing in order the manufacturing method of a nitrogen-doped silicon substrate according to an embodiment of the present invention. [Figure 4A] It is a cross-sectional view schematically showing the manufacturing process of a nitrogen-doped silicon substrate according to an embodiment of the present invention. [Figure 4B] It is a cross-sectional view schematically showing the manufacturing process of a nitrogen-doped silicon substrate according to an embodiment of the present invention.

Mode for Carrying Out the Invention

[0011] [[ID= 13]] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. The same reference numerals are used for the same components on the drawings, and redundant descriptions thereof are omitted.

[0012] The present invention can be subjected to various modifications and can have various embodiments. Specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the technical scope by specific embodiments, and it should be understood that it includes all modifications, equivalents, or alternatives included in the idea and technical scope of the present invention. When it is determined that a specific description of related known technologies obscures the gist in explaining the embodiments, the detailed description thereof is omitted.

[0013] FIG. 1A is a diagram schematically showing a nitrogen-doped silicon substrate 10 according to an embodiment of the present invention, and FIG. 1B is a graph showing the nitrogen concentration of the nitrogen-doped silicon substrate 10 of FIG. 1A.

[0014] Referring to FIGS. 1A and 1B, the nitrogen-doped silicon substrate 10 is a base substrate 100 including an edge portion 104 and a central portion 102.

[0015] The base substrate 100 includes a first surface and a second surface that face each other, and the surface shown in FIG. 1A is the first surface of the base substrate 100. The base substrate 100 includes an element region (not shown) and an edge region (not shown) surrounding the element region. The element region is a region where a plurality of element patterns are formed on the base substrate 100. That is, the element patterns are formed on the first surface of the base substrate 100. The edge region surrounds the element region. The edge region means the bevel edge of the base substrate 100.

[0016] The base substrate 100 is bulk silicon or SOI (silicon-on-insulator). The base substrate 100 is a silicon substrate or includes other substances such as silicon germanium, SGOI (silicon germanium on insulator), indium antimonide, lead telluride compound, indium arsenide, indium phosphide, gallium arsenide or gallium antimonide, but is not limited thereto.

[0017] The central portion 102 in FIG. 1A corresponds to the element region of the base substrate 100, and the edge portion 104 corresponds to the edge region of the base substrate 100. However, the present invention is not limited thereto. In some other embodiments, the element region of the base substrate 100 may be included in the central portion 102 in FIG. 1A, while the edge region may be included in both the central portion 102 and the edge portion 104. The element region of the base substrate 100 is a region where nitrogen is not doped, and the edge region of the base substrate 100 includes both a region where nitrogen is not doped and a region where nitrogen is doped.

[0018] In this specification, expressions such as "nitrogen atom" and "nitrogen" are expressions that refer to all N included in N and compounds containing N (for example, nitride-based compounds).

[0019] The central portion 102 of the base substrate 100 contains Si. In exemplary embodiments, the central portion 102 of the base substrate 100 does not have to contain nitrogen. Alternatively, in other embodiments, the central portion 102 of the base substrate 100 may contain a small amount of nitrogen.

[0020] The edge portion 104 of the base substrate 100 contains nitrogen. The edge portion 104 of the base substrate 100 includes an outer edge portion 104b and an inner edge portion 104a. The nitrogen concentration in the outer edge portion 104b is greater than the nitrogen concentration in the inner edge portion 104a. Since the central portion 102 of the base substrate 100 does not contain nitrogen, the nitrogen concentrations in the outer edge portion 104b and the inner edge portion 104a of the base substrate 100 are higher than the nitrogen concentration in the central portion 102. In an exemplary embodiment, the inner edge portion 104a surrounds the central portion 102 in a ring shape, and the outer edge portion 104b surrounds the inner edge portion 104a in a ring shape. The diameter of the outer edge portion 104b is the same as the diameter of the base substrate 100. The diameter of the outer edge portion 104b is larger than the diameter of the inner edge portion 104a, and the diameter of the inner edge portion 104a is larger than the diameter of the central portion 102.

[0021] Referring also to Figure 1B, the radius of the outer edge portion 104b is the reference length r0, the radius of the inner edge portion 104a is the second length r2, and the radius of the central portion 102 is the first length r1. The region from the center of the base substrate 100 to the first length r1 corresponds to the central portion 102 of the base substrate 100, the region that is greater than the first length r1 and less than or equal to the second length r2 from the center of the base substrate 100 corresponds to the inner edge portion 104a of the base substrate 100, and the region that is greater than the second length r2 and less than or equal to the reference length r0 from the center of the base substrate 100 corresponds to the outer edge portion 104b of the base substrate 100.

[0022] In some exemplary embodiments, the difference between the first length r1 and the second length r2 is the same as the difference between the second length r2 and the reference length r0, but the present invention is not limited thereto. The difference between the first length r1 and the second length r2 may be greater than or less than the difference between the second length r2 and the reference length r0.

[0023] In an exemplary embodiment, the base substrate 100 is a 12-inch silicon substrate. When the base substrate 100 is a 12-inch silicon substrate, the reference length r0, which is the radius of the base substrate 100, is approximately 150 mm. In this case, the edge portion 104 is a region located approximately 147 mm to 150 mm away from the center of the base substrate 100. For example, the edge portion 104 is a region located 149 mm to 150 mm away from the center of the base substrate 100.

[0024] In an exemplary embodiment, if the base substrate 100 is a 12-inch silicon substrate, the first length r1 is in the range of 147 mm to 149 mm, and the second length r2 is longer than the first length r1 and shorter than 150 mm.

[0025] However, the base substrate 100 may be an 8-inch substrate, a 16-inch substrate, or any other substrate having different dimensions. If the base substrate 100 is an 8-inch substrate, the reference length r0, which is the radius of the base substrate 100, is approximately 100 mm. In this case, the edge portion 104 is the area approximately 98 mm to 100 mm away from the center of the base substrate 100. For example, the edge portion 104 is the area 99.3 mm to 100 mm away from the center of the base substrate 100.

[0026] In an exemplary embodiment, if the base substrate 100 is an 8-inch silicon substrate, the first length r1 is in the range of 98 mm to 99.3 mm, and the second length r2 is greater than the first length r1 and less than 100 mm.

[0027] If the base substrate 100 is a 16-inch substrate, the reference length r0, which is the radius of the base substrate 100, is approximately 200 mm. In this case, the edge portion 104 is the region located approximately 196 mm to 200 mm away from the center of the base substrate 100. For example, the edge portion 104 is the region located 198.7 mm to 200 mm away from the center of the base substrate 100.

[0028] In an exemplary embodiment, if the base substrate 100 is a 16-inch silicon substrate, the first length r1 is in the range of 196 mm to 198.7 mm, and the second length r2 is greater than the first length r1 and less than 200 mm.

[0029] In other words, the radius of the edge portion 104 changes according to the radius of the base substrate 100. In an exemplary embodiment, the radius of the edge portion 104 is approximately 147 / 150 to 149 / 150 times the radius of the base substrate 100.

[0030] For convenience, this specification describes the case where the diameter of the base substrate 100 is 12 inches, but as stated above, the present invention is not limited thereto.

[0031] Referring to Figure 1B, the atomic concentration of nitrogen contained in the inner edge portion 104a of the base substrate 100 is the first concentration c1, and the atomic concentration of nitrogen contained in the outer edge portion 104b is the second concentration c2. In this exemplary embodiment, the second concentration c2 is greater than the first concentration c1.

[0032] For example, the inner edge portion 104a has a uniform nitrogen atom concentration of a first concentration c1 throughout its entire region, and the outer edge portion 104b has a uniform nitrogen atom concentration of a second concentration c2 throughout its entire region, but there is a discontinuous change in nitrogen atom concentration at the boundary between the inner edge portion 104a and the outer edge portion 104b. The above characteristics will be described later with reference to the manufacturing process of the nitrogen-doped silicon substrate 10, which is shown in Figures 3A to 3D.

[0033] In an exemplary embodiment, the first concentration c1 and the second concentration c2 are each 1 × 10 10atom / cm 3 ~1 × 10 19 atom / cm 3 This is within the specified range. The central part 102 of the substrate does not necessarily need to contain nitrogen atoms.

[0034] In some embodiments, the edge portion 104 may contain elements such as carbon and oxygen along with nitrogen atoms. For example, the edge portion 104 may contain SiCN. For convenience of explanation, this specification uses expressions such as "nitrogen atom" and "nitrogen," but even if the edge portion 104 contains a carbide compound, it can affect the first concentration c1 and the second concentration c2 in the same way as if it contained only nitride compounds.

[0035] In Figures 1A and 1B, the edge portion 104 is shown as including only the outer edge portion 104b and the inner edge portion 104a. However, this is merely an illustrative example, and the edge portion 104 may be a collection of three or more edge regions. That is, there may be three or more edge regions surrounding the central portion 102 in a ring shape. The further the edge region is located from the center of the base substrate 100, the higher the nitrogen concentration, and there is a discontinuous change in nitrogen concentration at each interface. In this case, the nitrogen concentration of all three or more edge regions is 1 × 10⁻⁶. 10 atom / cm 3 ~1 × 10 19 atom / cm 3 They have different values ​​in between.

[0036] Figure 2A is a simplified diagram showing a nitrogen-doped silicon substrate 10a according to one embodiment of the present invention, and Figure 2B is a graph showing the nitrogen concentration of the nitrogen-doped silicon substrate 10a in Figure 2A.

[0037] Referring to Figures 2A and 2B, the nitrogen-doped silicon substrate 10a is a base substrate 100 including the edge portion 104 and the central portion 102.

[0038] The base substrate 100 includes a first surface and a second surface that face each other, and the surface shown in Figure 2A is the first surface of the base substrate 100. The base substrate 100 and central portion 102 in Figure 2A are substantially identical to the base substrate 100 and central portion 102 in Figure 1A, respectively, so a detailed explanation of the base substrate 100 and central portion 102 is omitted.

[0039] Referring again to Figure 2A in conjunction with Figure 2B, if the radius of the base substrate 100 is defined as the reference length r0, then the region from the center of the base substrate 100 to the first length r1 corresponds to the central part 102 of the base substrate 100, and the region that is greater than the first length r1 and less than or equal to the reference length r0, from the center of the base substrate 100 corresponds to the edge part 104 of the base substrate 100.

[0040] In an exemplary embodiment, the nitrogen concentration gradient contained in the edge portion 104 that surrounds the central portion 102 of the base substrate 100 in a ring shape differs from the nitrogen concentration gradient contained in the edge portion 104 shown in Figures 1A and 1B, and changes continuously depending on the distance from the center of the base substrate 100.

[0041] More specifically, the concentration of nitrogen in the edge portion 104 increases as you move away from the center of the base substrate 100.

[0042] Figure 2B shows that the nitrogen concentration in the edge portion 104 increases more rapidly as it moves away from the center of the base substrate 100, but the present invention is not necessarily limited to this. For example, the nitrogen concentration in the edge portion 104 may increase with a relatively constant slope regardless of the distance from the center of the base substrate 100, or the change in the slope may gradually decrease as the distance increases.

[0043] Unlike the nitrogen-doped silicon substrate 10 shown in Figure 1A, the nitrogen-doped silicon substrate 10a in Figure 2A exhibits a continuous change in nitrogen atom concentration. These characteristics will be described later with reference to the manufacturing process of the nitrogen-doped silicon substrate 10a, as shown in Figures 4A and 4B.

[0044] The concentration of nitrogen contained in the edge portion 104 can have various values from 0 to the reference concentration c0. In an exemplary embodiment, the reference concentration c0 is 1×10 10 atom / cm 3 ~1×10 10 atom / cm 3 in the range. The central portion 102 of the substrate may not contain nitrogen atoms.

[0045] In some embodiments, the edge portion 104 may contain elements such as carbon and oxygen together with nitrogen atoms. For example, the edge portion 104 may contain SiCN. In this specification, for convenience of explanation, expressions such as "nitrogen atom" and "nitrogen" are used. However, even when the edge portion 104 partially contains a carbide compound, it can affect the reference concentration c0 in the same manner as when only a nitride-based compound is contained.

[0046] In an exemplary embodiment, the base substrate 100 is a 12-inch silicon substrate. When the base substrate 100 is a 12-inch silicon substrate, the reference length r0, which is the radius of the base substrate 100, is approximately 150 mm, and the first length r1 is in the range of 147 mm to 149 mm. In this case, since the edge portion 104 corresponds to a region that is greater than the first length r1 and less than or equal to the reference length r0 from the center of the base substrate 100, when the first length r1 is 147 mm, the edge portion 104 is a region that is 147 mm to 150 mm away from the center of the base substrate 100, and when the first length r1 is 149 mm, the edge portion 104 is a region that is 149 mm to 150 mm away from the center of the base substrate 100.

[0047] However, the base substrate 100 may be an 8-inch substrate, a 16-inch substrate, or any substrate having other dimensions.

[0048] In an exemplary embodiment, if the base substrate 100 is an 8-inch substrate, the reference length r0, which is the radius of the base substrate 100, is approximately 100 mm, and the first length r1 is in the range of 98 mm to 99.3 mm. In this case, the edge portion 104 corresponds to the region that is greater than the first length r1 and less than or equal to the reference length r0 from the center of the base substrate 100. Therefore, if the first length r1 is 98 mm, the edge portion 104 is the region that is 98 mm to 100 mm away from the center of the base substrate 100, and if the first length r1 is 99.3 mm, the edge portion 104 is the region that is 99.3 mm to 100 mm away from the center of the base substrate 100.

[0049] In an exemplary embodiment, if the base substrate 100 is a 16-inch substrate, the reference length r0, which is the radius of the base substrate 100, is approximately 200 mm, and the first length r1 is in the range of 196 mm to 198.7 mm. In this case, the edge portion 104 corresponds to the region that is greater than the first length r1 and less than or equal to the reference length r0 from the center of the base substrate 100. Therefore, if the first length r1 is 196 mm, the edge portion 104 is the region that is 196 mm to 200 mm from the center of the base substrate 100, and if the first length r1 is 198.7 mm, the edge portion 104 is the region that is 198.7 mm to 200 mm from the center of the base substrate 100.

[0050] In other words, the radius of the edge portion 104 changes according to the radius of the base substrate 100. In an exemplary embodiment, the radius of the edge portion 104 is approximately 147 / 150 to 149 / 150 times the radius of the base substrate 100.

[0051] For convenience, this specification describes the case where the diameter of the base substrate 100 is 12 inches, but as stated above, the present invention is not limited thereto.

[0052] Figures 3A to 3D are diagrams illustrating, in order, a method for manufacturing a nitrogen-doped silicon substrate 10 according to one embodiment of the present invention. The method for manufacturing a nitrogen-doped silicon substrate 10, described with reference to Figures 3A to 3D, is a method of selectively doping nitrogen into the edge regions of individual silicon wafers obtained by cutting a silicon ingot.

[0053] Referring to Figure 3A, the base substrate 100 is prepared. The base substrate 100 is a silicon substrate that does not contain nitrogen, and is obtained by cutting a silicon ingot as described above.

[0054] Referring to Figure 3B, the first mask M1 is placed on the base substrate 100. The first mask M1 is positioned so as to vertically overlap the base substrate 100 and has a smaller planar area than the base substrate 100. Although the base substrate 100 and the first mask M1 are shown as being circular in shape, the present invention is not limited to this.

[0055] The region not covered by the first mask M1 is defined as the outer edge portion 104b.

[0056] Referring to Figure 3C, the outer edge portion 104b is doped with nitrogen at a predetermined concentration (hereinafter referred to as "primary doping"), and then the first mask M1 is removed. Nitrogen does not penetrate the region covered by the first mask M1, and nitrogen atoms are doped only in the outer edge portion 104b.

[0057] In exemplary embodiments, Rapid Thermal Annealing (RTA) and / or plasma are used for nitrogen doping.

[0058] Referring to Figure 3D, the second mask M2 is placed on the base substrate 100 in the region surrounded by the outer edge portion 104b. The second mask M2 is positioned so as to vertically overlap the base substrate 100 and has a smaller planar area than the first mask M1 (see Figure 3B). The second mask M2 is shown as having a circular shape, but the present invention is not limited to this.

[0059] Of the region not covered by the second mask M2, the region excluding the outer edge portion 104b is defined as the inner edge portion 104a.

[0060] Next, after nitrogen doping (hereinafter referred to as "secondary doping") is performed on the inner edge portion 104a and the outer edge portion 104b at a predetermined concentration, the result shown in Figure 1A can be obtained by removing the second mask M2.

[0061] Nitrogen does not penetrate the region covered by the second mask M2, and nitrogen atoms are doped only at the outer edge portion 104b and the inner edge portion 104a. In exemplary embodiments, RTA and / or plasma are used for nitrogen doping.

[0062] When comparing primary and secondary doping, the concentrations of nitrogen atoms doped in the two doping processes may be the same or different. For example, the concentration of nitrogen atoms doped in primary doping may be greater or less than the concentration of nitrogen atoms doped in secondary doping.

[0063] According to an exemplary embodiment, the inner edge portion 104a is doped with nitrogen atoms by a secondary doping process, while the outer edge portion 104b is doped with nitrogen atoms in both a primary and a secondary doping process. As a result, in the results shown in Figure 1A, the concentration of nitrogen atoms in the outer edge portion 104b is higher than the concentration of nitrogen atoms in the inner edge portion 104a (see Figure 1B).

[0064] Furthermore, in both primary and secondary doping, a mask was formed in the region where nitrogen doping was not performed, resulting in discontinuous changes in nitrogen atom concentration at the boundary between the central portion 102 and the inner edge portion 104a, and at the boundary between the inner edge portion 104a and the outer edge portion 104b.

[0065] Furthermore, in primary and / or secondary doping, not only nitride-based materials but also carbide-based materials may be used for doping. For example, the dopant may contain SiCN, and the dopant may also contain oxygen atoms.

[0066] The size of the outer edge portion 104b is determined by the size of the first mask M1, and the size of the inner edge portion 104a is determined by the size of the second mask M2. Therefore, the sizes of the outer edge portion 104b and the inner edge portion 104a can be set by adjusting the sizes of the first mask M1 and the second mask M2.

[0067] In Figure 1A, the edge portion 104 is shown to include two edge regions and have one concentration change interface; however, in some other embodiments, the edge portion 104 may include N (where N is a natural number greater than or equal to 3) edge regions and have N-1 concentration change interfaces.

[0068] If the edge portion 104 contains N edge regions, N masks of different sizes are required, and the same process as described above can be repeated with reference to Figures 3A and 3D to form the N edge regions. When multiple masks are used, the area of ​​the mask used in each process is smaller than the area of ​​the mask used in the previous process. Therefore, edge regions further from the center of the base substrate 100 are exposed to more nitrogen during the nitrogen doping process and thus have a higher nitrogen concentration. In this case, the nitrogen concentration of each of the N edge regions is 1 × 10⁻⁶. 10 atom / cm 3 ~1 × 10 19 atom / cm 3 They have different values ​​within the given range.

[0069] Furthermore, although Figures 3A to 3D illustrate a nitrogen doping process performed only on the first surface of the base substrate 100, the present invention is not limited thereto. In some embodiments, the process described with reference to Figures 3A to 3D may be performed only on the second surface of the base substrate 100. In other embodiments, after performing the process described with reference to Figures 3A to 3D on the first surface of the base substrate 100, the process described with reference to Figures 3A to 3D may be performed again on the second surface to form a nitrogen concentration gradient on the edge portion 104 on both sides of the base substrate 100.

[0070] When the processes shown in Figures 3A to 3D are performed on the second surface of the base substrate 100, the constraints imposed by the size of the mask can be relatively reduced compared to when the processes are performed on the first surface. In other words, when the processes are performed on the second surface, a smaller mask can be used than when the processes are performed on the first surface. This is because the electrical influence on the device region from the second surface of the base substrate 100 is smaller compared to the first surface.

[0071] The method for manufacturing the nitrogen-doped silicon substrate 10, as described with reference to Figures 3A to 3D, has the advantage that the size of the nitrogen-doped area (i.e., the size of the mask), the number of masks, the nitrogen doping concentration, etc., can be adjusted by user settings, and the possibility of substrate warpage can be easily controlled.

[0072] Figures 4A and 4B are simplified cross-sectional views illustrating the manufacturing process of a nitrogen-doped silicon substrate 10a (see Figure 2A) according to one embodiment of the present invention.

[0073] The manufacturing process for nitrogen-doped silicon substrate 10a, as described with reference to Figures 4A and 4B, can utilize the floating zone method. Generally, the floating zone method is a method that induces crystal growth by locally heating a rod-shaped silicon.

[0074] The floating zone method begins by preparing a high-purity single-crystal silicon seed and a polycrystalline silicon rod, and then melting a portion of the polycrystalline silicon rod using an induction heating device. In this process, the induction heating device melts only a portion of the polycrystalline silicon rod, and the molten region moves along the entire rod.

[0075] As the molten region moves, the remaining silicon cools and solidifies into a single-crystal structure. The seed single-crystal structure propagates through the molten region to the polycrystalline silicon rod, and the entire silicon rod grows as a single-crystal structure. By repeating the above process while the molten silicon region pushes out impurities as it moves, a high-purity silicon ingot can be formed.

[0076] According to the floating zone method, the molten region pushes out impurities, resulting in ingots with lower impurity concentrations compared to those formed by the Czochralski method. Furthermore, since melting occurs only locally, a container for holding the silicon is not required, thus preventing the possibility of contamination from impurities originating from the container.

[0077] Referring again to Figure 4A, an ingot manufacturing apparatus 200 is prepared, which includes a mold 20, a first nitrogen powder injection channel 30a, a second nitrogen powder injection channel 30b, and a nozzle 40.

[0078] The ingot manufacturing apparatus 200 shown in Figure 4A manufactures ingots using silicon powder 20p.

[0079] In an exemplary embodiment, the silicon powder 20p is a high-purity Si powder free of impurities. The nitrogen powder 30p injected through the first nitrogen powder injection channel 30a and the second nitrogen powder injection channel 30b contains a nitride-based material.

[0080] First, silicon powder 20p is placed into a cylindrical mold 20 and compressed at a predetermined pressure to form a preform. In an exemplary embodiment, the preform is a hard, compressed mass of silicon powder in a polycrystalline state.

[0081] A localized molten region is formed from one end of the preform using an induction heating device, and as the molten region slowly moves, the solidified portion recrystallizes into a single-crystal structure. In some embodiments, a single-crystal seed is used to guide the growth direction.

[0082] As the preform in the mold 20 is single-crystallized and drawn out as an ingot 50 through the nozzle 40, the edges of the ingot 50 are doped with nitrogen by nitrogen powder 30p injected from the first nitrogen powder injection channel 30a and the second nitrogen powder injection channel 30b. In some exemplary embodiments, a heat treatment process may be carried out concurrently with the nitrogen doping process at the edges.

[0083] Figure 4A is a cross-sectional view of the ingot manufacturing apparatus 200, and the first nitrogen powder injection passage 30a and the second nitrogen powder injection passage 30b are shown covering both sides of the mold 20. However, in a plan view, the first nitrogen powder injection passage 30a and the second nitrogen powder injection passage 30b surround the mold 20 in a ring shape and have a structure formed as a single unit. In other words, the first nitrogen powder injection passage 30a and the second nitrogen powder injection passage 30b constitute a single nitrogen powder injection passage 30.

[0084] As a result, by slicing the ingot 50 formed by the ingot manufacturing apparatus 200 shown in Figure 4A, a nitrogen-doped silicon substrate 10a as shown in Figure 2A can be obtained.

[0085] According to the manufacturing method of the ingot 50 shown in Figure 4A, the ingot 50 is already doped with nitrogen at its edges by nitrogen powder 30p supplied from the nitrogen powder injection channel 30 before it is sliced ​​as a substrate. Therefore, unlike the process of selectively doping one side of the base substrate 100 with nitrogen, as described with reference to Figures 3A to 3D, the nitrogen-doped silicon substrate 10a is similarly doped with nitrogen at its edges without distinction between the first and second surfaces.

[0086] Figure 4B is a simplified cross-sectional view showing the manufacturing process of a nitrogen-doped silicon substrate 10a according to one embodiment of the present invention.

[0087] Referring to Figure 4B, an ingot manufacturing apparatus 200' is prepared, which includes a mold 20', a first nitrogen coating section 30a', a second nitrogen coating section 30b', and a nozzle 40'.

[0088] The manufacturing process for nitrogen-doped silicon substrate 10a, as described with reference to Figure 4A, involves injecting silicon powder 20p and nitrogen powder 30p into a mold 20 and a nitrogen powder injection channel 30, respectively, and then separating the injection channels to produce an ingot 50. In contrast, the manufacturing process for nitrogen-doped silicon substrate 10a, as described with reference to Figure 4B, involves coating the edges of a polycrystalline silicon rod 20s with a nitride-based material in a floating zone method, and then growing it as an ingot.

[0089] The first nitrogen coating section 30a' and the second nitrogen coating section 30b' in Figure 4B are shown to cover both sides of the mold 20', similar to the first nitrogen powder injection channel 30a and the second nitrogen powder injection channel 30b in Figure 4A. However, in a plan view, the first nitrogen coating section 30a' and the second nitrogen coating section 30b' surround the mold 20' in a ring shape and have a structure formed as a single unit. That is, the first nitrogen coating section 30a' and the second nitrogen coating section 30b' constitute a single nitrogen coating section 30'.

[0090] The nitrogen coating section 30' heats the side surface 30s of the polycrystalline silicon rod, which is part of the polycrystalline silicon rod 20s placed inside the mold 20', and dops the side surface 30s of the polycrystalline silicon rod with a nitride-based material. The doped nitride-based material dops mainly the edge of the polycrystalline silicon rod 20s and does not penetrate into the interior of the polycrystalline silicon rod 20s beyond a predetermined depth. Therefore, when the ingot 50 obtained by the above process is sliced, a nitrogen-doped silicon substrate 10a shown in Figure 2A can be obtained.

[0091] The side surface 30s of the polycrystalline silicon rod shown in Figure 4B indicates the region in the cylindrical polycrystalline silicon rod 20s that is doped with nitrogen due to the influence of the nitrogen coating portion 30'.

[0092] According to the manufacturing method of the ingot 50 shown in Figure 4B, before the ingot 50 is sliced ​​as a substrate, nitrogen is already doped into its side surface 30s by the nitride-based material and heat supplied by the nitrogen coating section 30'. Therefore, unlike the process of selectively doping nitrogen into one side of the base substrate 100, as described with reference to Figures 3A to 3D, the nitrogen-doped silicon substrate 10a is similarly doped with nitrogen at its edges, without distinction between the first and second surfaces.

[0093] Exemplary embodiments have been disclosed in the drawings and specification. While specific terms have been used to describe embodiments in this specification, these are used solely for the purpose of illustrating the technical idea of ​​the present invention and not to limit its meaning or scope. Therefore, those skilled in the art will understand from these that a variety of modifications and equivalent other embodiments are possible. [Explanation of Symbols]

[0094] 10, 10a Silicon substrate 20, 20' mold 30 Nitrogen powder injection channel 30' Nitrogen-coated section 40, 40' nozzle 50 ingots 100 base board 102 Central part 104a Inner edge 104b Outer edge 200, 200' Ingot Manufacturing Equipment

Claims

1. The steps include preparing a circular base substrate which includes a central portion, an inner edge portion that surrounds the central portion in a ring shape, and an outer edge portion that surrounds the inner edge portion in a ring shape, and which includes a first surface and a second surface facing the first surface, The steps include: placing a first mask covering the central portion and the inner edge portion on the first surface of the base substrate; A primary doping step of doping nitrogen onto the outer edge portion of the base substrate that is not covered by the first mask on the first surface of the base substrate, The steps include removing the first mask and placing a second mask covering the central portion on the first surface of the base substrate, A secondary doping step in which nitrogen is doped onto the outer edge portion and the inner edge portion of the base substrate that are not covered by the second mask on the first surface of the base substrate, The step of removing the second mask is included, The nitrogen atom concentration in the inner edge portion is constant as the first concentration, and the nitrogen atom concentration in the outer edge portion is constant as the second concentration. A method for manufacturing a nitrogen-doped silicon substrate, characterized in that the nitrogen atomic concentration changes discontinuously at the boundary between the outer edge portion and the inner edge portion.

2. The method for manufacturing a nitrogen-doped silicon substrate according to claim 1, characterized in that the second concentration is greater than the first concentration.

3. The first concentration and the second concentration are 1 × 10 １０ atom / cm ３ or 1 x 10 １９ atom / cm ３ A method for manufacturing a nitrogen-doped silicon substrate according to claim 1, characterized in that it is between the two.

4. The method for manufacturing a nitrogen-doped silicon substrate according to claim 1, characterized in that the radius of the second mask is in the range of 147 / 150 times to 149 / 150 times the length of the radius of the base substrate.

5. The steps include: placing a third mask having a smaller planar area than the base substrate on the second surface of the base substrate; The steps include: doping nitrogen in the region of the second surface of the base substrate that is not covered by the third mask; The steps include removing the third mask and placing a fourth mask having a smaller planar area than the third mask on the second surface of the base substrate, The steps include: doping nitrogen in the area of ​​the second surface of the base substrate that is not covered by the fourth mask; A method for manufacturing a nitrogen-doped silicon substrate according to claim 1, further comprising the step of removing the fourth mask.

6. The method for manufacturing a nitrogen-doped silicon substrate according to claim 5, characterized in that the nitrogen concentration gradient of the second surface and the nitrogen concentration gradient of the first surface of the base substrate are different from each other.

7. In an ingot manufacturing apparatus including a cylindrical mold and a nitrogen powder injection channel surrounding the mold in a ring shape, the steps include injecting silicon powder into the mold and injecting nitride powder into the nitrogen powder injection channel, The steps include: applying a predetermined pressure to the silicon powder to form a silicon powder mass that is compressed into a polycrystalline state, The steps include applying heat to the silicon powder mass to recrystallize it into a single crystal structure, The steps include forming an ingot from the silicon powder mass, The step includes slicing the ingot to form individual substrates, A method for manufacturing a nitrogen-doped silicon substrate, characterized in that, in the recrystallization step, nitrogen is doped onto the side surface of the ingot by the nitride powder introduced through the nitrogen powder injection channel.

8. Each of the individual substrates includes a nitrogen-doped region formed in a ring shape at its edge. The method for manufacturing a nitrogen-doped silicon substrate according to claim 7, characterized in that the nitrogen-doped region has a higher nitrogen concentration as it is further away from the center of each of the individual substrates.

9. An ingot manufacturing apparatus comprising a cylindrical mold and a nitrogen-coated portion surrounding the mold in a ring shape, comprising the steps of forming a polycrystalline silicon rod inside the mold, The nitrogen coating portion heats the side surface of the polycrystalline silicon rod placed inside the mold, The steps include doping the side surface of the polycrystalline silicon rod with a nitride-based material, The steps include: recrystallizing the aforementioned polycrystalline silicon rod into an ingot; The step includes slicing the ingot to form individual substrates, A method for manufacturing a nitrogen-doped silicon substrate, characterized in that each of the individual substrates includes a nitrogen-doped region formed in a ring shape at its edge.

10. The method for manufacturing a nitrogen-doped silicon substrate according to claim 9, characterized in that the nitrogen-doped region has a higher nitrogen concentration as it is further away from the center of each of the individual substrates, and the change in the concentration is continuous.

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