Method for manufacturing silicon nitride substrate and silicon nitride base material

Abstract

In this invention, first, a scribe line (110) is formed, by means of a laser, on a first surface (102) of a nitride ceramic base material (100). Then, the nitride ceramic base material (100) is split along the scribe line (110). The scribe line (110) includes a plurality of recessed portions (112). The plurality of recessed portions (112) are formed in one row on the first surface (102) of the nitride ceramic base material (100). The depth (d) of each of the plurality of recessed portions (112) is from 0.70 times to 1.10 times the opening width (w) of each of the plurality of recessed portions (112). The opening width (w) of each of the plurality of recessed portions (112) is from 1.00 times to 1.10 times the distance (p) between the centers of the plurality of recessed portions (112) which are adjacent.

Description

[Technical field]

[0001] The present invention relates to a method for producing a nitride ceramic substrate and a nitride ceramic base material. [Background technology]

[0002] Nitride ceramic substrates are sometimes used as electronic components. The nitride ceramic substrates are excellent in various respects, such as high thermal conductivity or high insulation. The nitride ceramic substrates can be used in various electronic devices, such as power modules.

[0003] Various ceramic substrates including nitride ceramic substrates can be manufactured by dividing a ceramic base material by laser scribing, as described in, for example, Patent Documents 1 to 3. Scribe lines are formed in the ceramic base material by laser scribing. The ceramic base material is divided into a plurality of ceramic substrates along the scribe lines.

[0004] Patent Document 1 describes dividing a nitride ceramic substrate into a plurality of nitride ceramic substrates by laser scribing. The scribe lines formed by laser scribing include a plurality of recesses formed in a line on the surface of the nitride ceramic substrate. The opening width of the recesses is 0.04 mm to 0.5 mm, the depth of the recesses is 1 / 4 to 1 / 3 of the thickness of the nitride ceramic substrate, and the center-to-center distance between the plurality of recesses is 0.2 mm or less.

[0005] Patent Document 2 describes dividing an aluminum oxide base material into multiple aluminum oxide substrates by laser scribing. The scribe lines formed by the laser scribing include multiple recesses formed in a line on the surface of the nitride ceramic base material. The recesses have a conical shape.

[0006] Patent Document 3 describes dividing a silicon nitride base material into a plurality of silicon nitride substrates by laser scribing. The scribe lines formed by laser scribing have grooves that extend continuously in one direction. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2007-324301 A [Patent Document 2] JP 2013-175667 A [Patent Document 3] JP 2014-42066 A Summary of the Invention [Problem to be solved by the invention]

[0008] For the nitride ceramic substrate, there are cases where it is required to satisfactorily remove the brazing material from the nitride ceramic substrate, reduce the appearance of scribe lines in SAT (Scanning Acoustic Tomography), and satisfactorily crack the nitride ceramic substrate.

[0009] One example of the object of the present invention is to realize good removal of brazing material from a nitride ceramic substrate, reduction of scribe line imprinting in SAT, and good cracking of the nitride ceramic substrate. Other objects of the present invention will become apparent from the description of this specification. [Means for solving the problem]

[0010] One aspect of the present invention is forming a scribe line on a first surface of a nitride ceramic substrate by a laser; dividing the nitride ceramic substrate along the scribe lines; Including, the scribe line includes a plurality of recesses formed in a line on the first surface of the nitride ceramic substrate, a depth of each of the plurality of recesses is 0.70 to 1.10 times the opening width of each of the plurality of recesses; In the method for producing a nitride ceramic substrate, the opening width of each of the plurality of recesses is not less than 1.00 times and not more than 1.10 times the center-to-center distance of the plurality of recesses.

[0011] Another aspect of the present invention is A first surface having a scribe line formed thereon; the scribe line includes a plurality of recesses formed in a line on the first surface, a depth of each of the plurality of recesses is 0.70 to 1.10 times the opening width of each of the plurality of recesses; The nitride ceramic substrate has an opening width of each of the plurality of recesses that is not less than 1.00 times and not more than 1.10 times the center-to-center distance of the plurality of recesses. Effect of the Invention

[0012] According to one aspect of the present invention, it is possible to realize good removal of brazing material from a nitride ceramic base material, reduction in the appearance of scribe lines in SAT, and good cracking of the nitride ceramic base material. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a plan view of a nitride ceramic substrate according to an embodiment. [Diagram 2] 2 is a cross-sectional view along the line AA′ of FIG. 1. [Diagram 3] FIG. 3 is an enlarged view of the recess shown in FIG. [Figure 4] FIG. 2 is a plan view of an example of an entire nitride ceramic substrate. [Diagram 5] FIG. 5 is an enlarged view of a region α shown in FIG. [Figure 6] FIG. 5 is an enlarged view of a region β shown in FIG. [Figure 7]2A to 2C are diagrams illustrating an example of a method for manufacturing a nitride ceramic substrate (base plate) in an embodiment. [Figure 8] 2A to 2C are diagrams illustrating an example of a method for manufacturing a nitride ceramic substrate (base plate) in an embodiment. [Figure 9] 2A to 2C are diagrams illustrating an example of a method for manufacturing a nitride ceramic substrate (base plate) in an embodiment. [Figure 10] 2A to 2C are diagrams illustrating an example of a method for manufacturing a nitride ceramic substrate (base plate) in an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same components are given the same reference numerals and the description will be omitted as appropriate.

[0015] Fig. 1 is a plan view of a nitride ceramic substrate 100 according to an embodiment of the present invention. Fig. 2 is a cross-sectional view taken along line AA' of Fig. 1. Fig. 3 is an enlarged view of a recess 112 shown in Fig. 2.

[0016] An outline of a method for manufacturing a nitride ceramic substrate in an embodiment will be described with reference to FIG. 2. First, a scribe line 110 is formed on the first surface 102 of the nitride ceramic substrate 100 by a laser. Next, the nitride ceramic substrate 100 is divided along the scribe line 110. The scribe line 110 includes a plurality of recesses 112. The plurality of recesses 112 are formed in a line on the first surface 102 of the nitride ceramic substrate 100. The depth d of each of the plurality of recesses 112 is 0.70 to 1.10 times the opening width w of each of the plurality of recesses 112. The opening width w of each of the plurality of recesses 112 is 1.00 to 1.10 times the center-to-center distance p of the plurality of recesses 112.

[0017] According to the present embodiment, it is possible to realize satisfactory removal of the brazing material from the nitride ceramic substrate 100, reduction in the appearance of the scribe line in SAT (Scanning Acoustic Tomography), and satisfactory cracking of the nitride ceramic substrate 100. As will be described in detail later, the present inventors have newly found that the respective characteristics of removal of the brazing material from the nitride ceramic substrate 100, appearance of the scribe line in SAT, and cracking of the nitride ceramic substrate 100 depend on various parameters, in particular, the depth d of the recess 112, the opening width w of the recess 112, and the center-to-center distance p of the plurality of recesses 112. As a result of the studies by the present inventors, it has become clear that satisfactory removal of the brazing material from the nitride ceramic substrate 100, reduction in the appearance of the scribe line in SAT, and satisfactory cracking of the nitride ceramic substrate 100 are realized when the depth d of the recess 112, the opening width w of the recess 112, and the center-to-center distance p of the plurality of recesses 112 are in the above-mentioned relationship.

[0018] The nitride ceramic substrate 100 will be described in detail with reference to FIGS.

[0019] The nitride ceramic substrate 100 can be, for example, a silicon nitride substrate or an aluminum nitride substrate, more specifically, a silicon nitride sintered body substrate or an aluminum nitride sintered body substrate.

[0020] The nitride ceramic substrate 100 has a first surface 102 and a second surface 104. In the example shown in Figures 1 and 2, a scribe line 110 is formed on the first surface 102. The second surface 104 is opposite the first surface 102. The thickness t of the nitride ceramic substrate 100 is the distance between the first surface 102 and the second surface 104.

[0021] The scribe line 110 includes a plurality of recesses 112. As shown in FIG. 1, the opening of each recess 112 has a circular shape. The recesses 112 are arranged at substantially equal intervals (center-to-center distance p). Line AA′ in FIG. 1 passes through the center of each recess 112. That is, the cross section shown in FIG. 2 includes the center of the recess 112. In the example shown in FIG. 2, the width of the recess 112 narrows toward the lower end of the recess 112, and the opening width w of the recess 112 is the width at the upper end of the recess 112. In the example shown in FIG. 2, the depth d of the recess 112 is the distance between the upper end and the lower end of the recess 112.

[0022] The depth d of the recesses 112 may be, for example, 9 / 64 to 2 / 9 times the thickness t of the nitride ceramic substrate 100, or 45 μm to 90 μm. If the depth d of the recesses 112 is too shallow, the nitride ceramic substrate 100 cannot be divided well along the scribe lines 110. On the other hand, if the depth d of the recesses 112 is too deep, it may be difficult to remove the brazing material that has entered the recesses 112. In contrast, when the depth d of the recesses 112 is within the above-mentioned range, these problems can be reduced.

[0023] The nitride ceramic substrate 100 will be described in detail with reference to FIG.

[0024] The recess 112 has a conical shape with a rounded tip, and has a rounded bottom in the cross section shown in Fig. 3. In a cross section including the center of the recess 112 (for example, the cross section AA' in Fig. 1 or a cross section along a direction perpendicular to the line AA' in Fig. 1), both side surfaces of the recess 112 are inclined so that an imaginary tangent l1 at an upper end UE1 of one inner side surface of the recess 112 and an imaginary tangent l2 at an upper end UE2 of the other inner side surface of the recess 112 intersect at an angle θ (tip angle). The tip angle θ can be, for example, 30° or more.

[0025] The nitride ceramic substrate 100 may have ridges 114. The ridges 114 are located around the periphery of the recesses 112. The ridges 114 are formed by a portion of the nitride ceramic substrate 100 rising up due to the effect of heating by the laser.

[0026] The ridges 114 may be removed. The ridges 114 may be removed, for example, by wet blasting.

[0027] FIG. 4 is a plan view of an example of the entire nitride ceramic substrate 100. As shown in FIG.

[0028] The scribe lines 110 of the nitride ceramic substrate 100 include a plurality of first scribe lines 110a and a plurality of second scribe lines 110b. The first scribe lines 110a extend in a first direction (X direction in FIG. 4). The second scribe lines 110b extend in a second direction (Y direction in FIG. 4). The second direction intersects with the first direction, and in the example shown in FIG. 4, the second direction is perpendicular to the first direction.

[0029] A plurality of partitioned regions RG are defined by a plurality of first scribe lines 110a and a plurality of second scribe lines 110b. The plurality of partitioned regions RG are arranged in a matrix. Each of the partitioned regions RG has a substantially rectangular shape. Nitride Ceramic Substrate 100 By dividing the nitride ceramic base material 100, a plurality of divided regions RG (a plurality of nitride ceramic substrates) are cut out from the nitride ceramic base material 100.

[0030] Figure 5 is an enlarged view of region α shown in Figure 4. Region α includes the intersection of scribe lines 110 formed by the intersection of first scribe line 110a and second scribe line 110b.

[0031] The first scribe line 110a includes a plurality of recesses 112 (a first group of recesses 112). The second scribe line 110b includes a plurality of recesses 112 (a second group of recesses 112). The recesses 112 of the second group of recesses 112 that are located closest to the first scribe line 110a do not overlap with any of the recesses 112 of the first group. If the first group of recesses 112 included in the first scribe line 110a and the second group of recesses 112 included in the second scribe line 110b overlap with each other, there is a risk that the nitride ceramic substrate 100 will be chipped at the overlapping portions of the recesses 112 after the nitride ceramic substrate 100 is divided. In contrast, according to this embodiment, the nitride ceramic substrate 100 Division of Subsequent chipping of the nitride ceramic substrate 100 can be reduced.

[0032] The center of the recess 112 located closest to the first scribe line 110a among the recesses 112 of the second group included in the second scribe line 110b is away from the center line C1 of the first scribe line 110a by a distance g2 in the second direction (Y direction). The distance g2 is, for example, 1.50 times or less, preferably 1.10 times or less, the center-to-center distance p2 of the recesses 112 of the second group. In this way, the recess 112 located closest to the first scribe line 110a among the recesses 112 of the second group included in the second scribe line 110b can be disposed close to the first scribe line 110a. Therefore, good cracking of the nitride ceramic substrate 100 at the intersection of the first scribe line 110a and the second scribe line 110b can be realized.

[0033] Figure 6 is an enlarged view of region β shown in Figure 4. Region β includes the corner of the scribe line 110 formed by the intersection of the first scribe line 110a and the second scribe line 110b.

[0034] At the corners of the scribe lines 110 (FIG. 6), as at the intersections of the scribe lines 110 (FIG. 5), the recesses 112 in the second group that are closest to the first scribe line 110a do not overlap any of the recesses 112 in the first group, and the recesses 112 in the second group that are closest to the first scribe line 110a and are included in the second scribe line 110b are disposed close to the first scribe line 110a. Therefore, even at the corners of the scribe lines 110 (FIG. 6), chipping of the nitride ceramic substrate 100 after the nitride ceramic substrate 100 is reduced, and favorable cracking of the nitride ceramic substrate 100 at the intersections of the first scribe line 110a and the second scribe line 110b can be achieved.

[0035] 7 to 10 are diagrams illustrating an example of a method for manufacturing a nitride ceramic substrate (base plate) according to an embodiment.

[0036] First, as shown in Fig. 7, a scribe line 110 (recess 112) is formed on the first surface 102 of the nitride ceramic substrate 100 by a laser. In this manner, a partitioned region RG (see also Fig. 4) is defined. The laser can be, for example, a carbon dioxide laser, a fiber laser, or a YAG laser, and in particular, a carbon dioxide laser with a pulse frequency of 1 kHz or more and a power of 25 W or more and 500 W or less.

[0037] Next, as shown in FIG. 8, a brazing material 120 and a metal layer 130 are formed on the first surface 102 and the second surface 104 of the nitride ceramic substrate 100, respectively.

[0038] The brazing material 120 may be an active metal brazing material. The active metal brazing material contains, for example, at least one of Ag, Cu, and Sn as a metal, and at least one of Ti and Zr as an active metal. The brazing material 120 may be formed by coating. In this case, a part of the brazing material 120 may enter the scribe line 110 (recess 112).

[0039] The metal layer 130 is bonded to the nitride ceramic substrate 100 via the brazing material 120 .

[0040] Next, the bonding between the nitride ceramic substrate 100 and the metal layer 130 is inspected by ultrasonic inspection. To the statue It has been found that the scribe line 110 is visible in the flaw detection image. The appearance of the scribe line 110 in the flaw detection image is determined as a joint void between the nitride ceramic substrate 100 and the metal layer 130, and is not distinguishable or is difficult to distinguish from a joint void caused by the brazing material 120, and therefore it is desirable to reduce the appearance of the scribe line 110 in the SAT. As will be described in detail later, the present inventor has newly found that the appearance of the scribe line 110 in the SAT depends on various parameters, in particular, the depth d of the recess 112, the opening width w of the recess 112, and the center-to-center distance p of the multiple recesses 112.

[0041] Next, as shown in FIG. 9, a resist 140 is formed on the metal layer 130 on the first surface 102 of the nitride ceramic substrate 100, and the nitride ceramic substrate 100 is 2nd side 104 A resist 140 is formed on the upper metal layer 130 .

[0042] 10, the brazing material 120 and the metal layer 130 are selectively etched with an etching solution (e.g., a ferric chloride solution, a cupric chloride solution, sulfuric acid, or hydrogen peroxide solution) while leaving the resist 140 shown in FIG. 9. The metal layer 130 on the first surface 102 of the nitride ceramic substrate 100 is formed into a circuit layer 132. The metal layer 130 on the second surface 104 of the nitride ceramic substrate 100 is formed into a heat dissipation layer 134.

[0043] As shown in Fig. 10, the brazing material 120 may remain in the scribe line 110 (recess 112). The brazing material 120 remaining in the scribe line 110 (recess 112) can be removed by a solution (e.g., an aqueous ammonium halide solution, an inorganic acid (e.g., sulfuric acid or nitric acid), or a hydrogen peroxide solution). As will be described in detail later, the present inventor has newly discovered that the ease with which this solution penetrates into the scribe line 110 (recess 112) (i.e., the characteristics of removing the brazing material 120 from the nitride ceramic substrate 100) depends on various parameters, in particular the depth d of the recess 112, the opening width w of the recess 112, and the center-to-center distance p of the multiple recesses 112.

[0044] Next, the nitride ceramic substrate 100 is divided along the scribe lines 110 to form a plurality of nitride ceramic substrates (base plates). As will be described in detail below, the present inventors have newly discovered that the cracking characteristics of the nitride ceramic substrate 100 depend on various parameters, in particular the depth d of the recesses 112, the opening width w of the recesses 112, and the center-to-center distance p of the plurality of recesses 112.

[0045] The nitride ceramic substrate (base plate) can be used as an electronic component. For example, a semiconductor element may be mounted on the circuit layer 132 of the nitride ceramic substrate (base plate) via solder. EXAMPLES

[0046] Example 1 In Example 1, the nitride ceramic substrate 100 was produced as follows.

[0047] The nitride ceramic substrate 100 was a silicon nitride sintered substrate having a thickness of 0.32 mm.

[0048] Scribe lines 110 (multiple recesses 112) were formed using a carbon dioxide laser. The depth d of the recesses 112 (e.g., FIG. 2), the opening width w of the recesses 112 (e.g., FIG. 2), the center-to-center distance p of the multiple recesses 112 (e.g., FIG. 2), and the tip angle θ of the recesses 112 (e.g., FIG. 3) are as shown in Table 1.

[0049] (Examples 2 to 7 and Comparative Examples 1 to 5) In Examples 2 to 7 and Comparative Examples 1 to 5, the depth d of the recesses 112 (e.g., FIG. 2), the opening width w of the recesses 112 (e.g., FIG. 2), the center-to-center distance p of the recesses 112 (e.g., FIG. 2), the tip angle θ of the recesses 112 (e.g., FIG. 3), and the type of laser used to form the scribe line 110 are as shown in Table 1. Examples 2 to 7 and Comparative Examples 1 to 5 were the same as Example 1 except for the points shown in Table 1.

[0050] (Removal of brazing material from nitride ceramic substrates) 7 to 10, the brazing material 120 and the metal layer 130 were selectively etched using the resist 140 and the etching solution. Furthermore, the brazing material 120 remaining on the nitride ceramic substrate 100 (for example, the brazing material 120 remaining in the scribe lines 110 (recesses 112)) was removed by the solution.

[0051] The remaining brazing material 120 in Examples 1 to 7 and Comparative Examples 1 to 4 is as shown in Table 1. In the column "Removal of brazing material" in Table 1, "◯" indicates that no remaining brazing material 120 was found in the scribe line 110 (recess 112), and "×" indicates that remaining brazing material 120 was found in the scribe line 110 (recess 112).

[0052] (Scribe lines captured in SAT) After forming the brazing material 120 on the nitride ceramic substrate 100, the nitride ceramic substrate 100 and the metal layer 130 were joined with the brazing material 120, and then the joining of the nitride ceramic substrate 100 and the metal layer 130 was inspected by ultrasonic inspection.

[0053] The appearance of the scribe line 110 in the SAT in Examples 1 to 7 and Comparative Examples 1 to 4 is as shown in Table 1. In the "SAT" column in Table 1, "◯" indicates that the appearance of the scribe line 110 in the SAT of the ultrasonic flaw detection test was not confirmed, and "×" indicates that the appearance of the scribe line 110 in the SAT of the ultrasonic flaw detection test was confirmed.

[0054] (Cracks in nitride ceramic substrate) After the brazing material 120 remaining on the nitride ceramic substrate 100 was removed, the nitride ceramic substrate 100 was divided along the scribe lines 110 by a four-point bending test.

[0055] The maximum bending stress at which the nitride ceramic substrate 100 in Examples 1 to 7 and Comparative Examples 1 to 4 broke is shown in Table 1.

[0056] The division failure rates of the nitride ceramic substrate 100 in Examples 1 to 7 and Comparative Examples 1 to 4 are shown in Table 1.

[0057] [Table 1]

[0058] From Comparative Example 1, it can be said that when the ratio w / p is 0.60 or less, it becomes difficult to crack the nitride ceramic substrate 100 satisfactorily.

[0059] From Comparative Example 2, it can be said that when the ratio d / w is 0.45 or less, it becomes difficult to obtain good cracking of the nitride ceramic substrate 100.

[0060] From Comparative Example 3, it can be said that when the ratio d / w is 1.20 or more, it becomes difficult to satisfactorily remove the brazing material 120 from the nitride ceramic substrate 100 .

[0061] From Comparative Example 4, it can be said that when the ratio w / p is 1.16 or more, it becomes difficult to reduce the reflection of the scribe line 110 in the SAT.

[0062] From these considerations, the ratio d / w is, for example, 0.70 to 1.10 below , preferably 0.75 or more and 1.08 or less, and the ratio w / p can be, for example, 1.00 or more and 1.10 or less, preferably 1.00 or more and 1.07 or less.

[0063] Although the embodiments of the present invention have been described above with reference to the drawings, these are merely examples of the present invention, and various configurations other than those described above can also be adopted. Below, examples of reference forms are given. 1. forming a scribe line on a first surface of a nitride ceramic substrate by a laser; dividing the nitride ceramic substrate along the scribe lines; Including, the scribe line includes a plurality of recesses formed in a line on the first surface of the nitride ceramic substrate, a depth of each of the plurality of recesses is 0.70 to 1.10 times the opening width of each of the plurality of recesses; The method for manufacturing a nitride ceramic substrate, wherein the opening width of each of the plurality of recesses is 1.00 to 1.10 times the center-to-center distance of the plurality of recesses. 2. In the method for producing a nitride ceramic substrate according to 1., In the step of forming the scribe lines, a protrusion is formed around each of the plurality of recesses. 3. In the method for producing a nitride ceramic substrate according to 2., The method for manufacturing a nitride ceramic substrate further comprises the step of removing the protuberances around each of the plurality of recesses after forming the scribe lines. 4. In the method for producing a nitride ceramic substrate according to any one of 1. to 3., A method for producing a nitride ceramic substrate, wherein the depth of each of the plurality of recesses is 9 / 64 times or more and 2 / 9 times or less the thickness of the nitride ceramic base material. 5. In the method for producing a nitride ceramic substrate according to any one of 1. to 4., The method for producing a nitride ceramic substrate, wherein the depth of each of the plurality of recesses is not less than 45 μm and not more than 90 μm. 6. The method for producing a nitride ceramic substrate according to any one of 1. to 5., the scribe lines include a first scribe line that includes a first group of recesses of the plurality of recesses and extends in a first direction, and a second scribe line that includes a second group of recesses of the plurality of recesses and extends in a second direction intersecting the first direction; A method for manufacturing a nitride ceramic substrate, wherein a recess in the second group of recesses that is located closest to the first scribe line does not overlap with any of the recesses in the first group. 7. The method for producing a nitride ceramic substrate according to 6., a center of the recess in the second group that is closest to the first scribe line is spaced in the second direction from a center line of the first scribe line by a distance equal to or less than 1.50 times the center-to-center distance of the recesses in the second group. 8. In the method for producing a nitride ceramic substrate according to any one of 1. to 5., The method for producing a nitride ceramic substrate, wherein the nitride ceramic substrate is a silicon nitride substrate or an aluminum nitride substrate. 9. A substrate having a first surface on which a scribe line is formed, the scribe line includes a plurality of recesses formed in a line on the first surface, a depth of each of the plurality of recesses is 0.70 to 1.10 times the opening width of each of the plurality of recesses; The opening width of each of the plurality of recesses is not less than 1.00 times and not more than 1.10 times the center-to-center distance of the plurality of recesses.

[0064] This application claims priority based on Japanese Patent Application No. 2019-048079, filed March 15, 2019, the disclosure of which is incorporated herein in its entirety. [Explanation of symbols]

[0065] 100 Nitride ceramic substrate 102 Page 1 104 2nd page 110 Scribe Line 110a First scribe line 110b Second scribe line 112 Recess 114 Prominence 120 Brazing material 130 Metal layer 132 circuit layer 134 Heat dissipation layer 140 Resist

Claims

1. A step of forming a scribe line on a first surface of a silicon nitride substrate by a laser; dividing the silicon nitride substrate along the scribe lines; Including, the scribe line includes a plurality of recesses formed in a line on the first surface of the silicon nitride substrate; The opening of each of the plurality of recesses is circular, a depth of each of the plurality of recesses is 0.70 to 1.10 times a width of an opening of each of the plurality of recesses; the opening width of each of the plurality of recesses is 1.00 times or more and 1.10 times or less the center-to-center distance of the plurality of recesses; the scribe lines include a first scribe line that includes a first group of recesses of the plurality of recesses and extends in a first direction, and a second scribe line that includes a second group of recesses of the plurality of recesses and extends in a second direction intersecting the first direction; A method for manufacturing a silicon nitride substrate, wherein a recess in the second group that is located closest to the first scribe line does not overlap with any of the recesses in the first group.

2. The method for producing a silicon nitride substrate according to claim 1, A method for manufacturing a silicon nitride substrate, wherein the step of forming scribe lines comprises forming a protuberance around each of the plurality of recesses.

3. The method for producing a silicon nitride substrate according to claim 2, The method for manufacturing a silicon nitride substrate further comprises the step of removing the protuberances around each of the plurality of recesses after forming the scribe lines.

4. The method for producing a silicon nitride substrate according to any one of claims 1 to 3, A method for manufacturing a silicon nitride substrate, wherein the depth of each of the plurality of recesses is 9 / 64 times or more and 2 / 9 times or less the thickness of the silicon nitride substrate.

5. The method for producing a silicon nitride substrate according to any one of claims 1 to 4, The method for manufacturing a silicon nitride substrate, wherein the depth of each of the plurality of recesses is 45 μm or more and 90 μm or less.

6. The method for producing a silicon nitride substrate according to any one of claims 1 to 5, a center of the recess in the second group that is closest to the first scribe line is a distance in the second direction from the center line of the first scribe line that is 1.50 times or less the center-to-center distance of the recesses in the second group.

7. A first surface having a scribe line formed thereon; the scribe line includes a plurality of recesses formed in a line on the first surface, The opening of each of the plurality of recesses is circular, a depth of each of the plurality of recesses is 0.70 to 1.10 times a width of an opening of each of the plurality of recesses; the opening width of each of the plurality of recesses is 1.00 times or more and 1.10 times or less the center-to-center distance of the plurality of recesses; the scribe lines include a first scribe line that includes a first group of recesses of the plurality of recesses and extends in a first direction, and a second scribe line that includes a second group of recesses of the plurality of recesses and extends in a second direction intersecting the first direction; a recess in the second group of recesses that is closest to the first scribe line does not overlap with any of the recesses in the first group of recesses.

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