JP6587205B2 - Silicon nitride ceramic aggregate substrate and method for manufacturing the same, and method for manufacturing silicon nitride ceramic sintered substrate - Google Patents

Description

  The present invention relates to a silicon nitride ceramic aggregate substrate for manufacturing a large number of circuit boards, a method for manufacturing the same, and a method for manufacturing a silicon nitride ceramic sintered substrate.

  Circuit circuit boards used for semiconductor modules, power modules, etc. use circuit ceramic substrates in terms of thermal conductivity, insulation, strength, etc., and this circuit ceramic substrate is made of a metal circuit board such as Cu or Al. A metal heat sink is joined to form a circuit board. Alumina and aluminum nitride materials have been widely used as ceramic substrates for circuits, but recently, silicon nitride with high strength and improved thermal conductivity has been used so that it can be used in more severe environments. It has become.

  As a technology for mass production of circuit boards, a metal plate such as a Cu plate is joined to one ceramic aggregate substrate having a size capable of cutting out a large number of circuit ceramic substrates by an active metal brazing method or a direct joining method. Then, a metal circuit board and a metal heat sink are formed by etching or the like. Next, the ceramic aggregate substrate is divided into predetermined sizes to obtain individual circuit boards.

  As a method of dividing into individual circuit boards, a recess or groove is formed in the ceramic aggregate substrate by laser processing before joining a Cu plate, etc., and the ceramic aggregate substrate with the circuit board is bent after joining to form the concave portion. Or the method of dividing | segmenting by a groove | channel is employ | adopted.

  The inventors of the present invention have formed a scribe hole (non-through hole) for splitting by laser processing on the sintered plate as-sintered, and dividing it by a dividing line by the scribe hole, so that the four sides of the sintered plate As a result, it was found that cracks and chips were likely to occur at the corners of the ceramic aggregate substrate. Even in the process of manufacturing a circuit board, there has been a problem that the yield of collecting circuit boards decreases when the edge portions are removed from the ceramic aggregate substrate to obtain a plurality of circuit boards.

  On the other hand, technologies for suppressing cracks and chipping when a circuit board is divided from a ceramic aggregate substrate by scribe holes or dividing grooves are disclosed in Japanese Patent Application Laid-Open No. 2008-198905 and Japanese Patent Application Laid-Open No. 2011-233687. ).

  Patent Document 1 is a technique for forming a chamfered portion penetrating in a thickness direction at a corner portion of at least one side surface of a circuit board, and the chamfered portion is formed as a diamond-shaped hollow portion by laser cutting. In Patent Document 2, a cut-out portion in which at least a corner portion intersecting with the dividing groove is formed in an arc shape is formed in a region where the dividing groove along the boundary between the circuit board region and the surrounding dummy region intersects. However, both relate to a technique for manufacturing each circuit board by dividing it from a ceramic aggregate substrate, and there is no description about a technique for manufacturing a ceramic aggregate substrate from a ceramic sintered substrate.

JP 2008-198905 JP 2011-233687 A

  In the prior art, when a ceramic aggregate substrate is produced from a rectangular ceramic sintered substrate, the problem of cracks and chips generated at the corners of the ceramic aggregate substrate has not been solved. In particular, in the case of a silicon nitride ceramics aggregate substrate having high strength and high thermal conductivity, the problem of cracking and chipping is likely to occur due to high strength and high toughness.

  An object of the present invention is to form a scribe hole for division on a sintered ceramic substrate as-sintered by laser processing, and then fire it with a dividing line connecting the centers of the scribe holes (hereinafter referred to as a side break line). In order to prevent the corners from cracking or chipping when the ceramic aggregate substrate is manufactured by dividing and removing the four edge portions of the bonded substrate, the silicon nitride ceramic aggregate substrate, its manufacturing method, and nitriding It is providing the manufacturing method of a silicon ceramic sintered substrate.

The present invention provides a silicon nitride ceramics aggregate substrate having a circuit forming part and an edge part for taking a large number of circuit boards from a rectangular silicon nitride ceramics sintered board having an ear around the silicon nitride ceramics aggregate substrate. A method for manufacturing a silicon nitride ceramic sintered substrate for manufacturing,
A scribe hole forming step for dividing the silicon nitride ceramic aggregate substrate and the ear portion, and a through hole forming step,
The scribe hole forming step forms a side break line by the scribe hole along the outer edge from the outer edge of the silicon nitride ceramic sintered substrate to the inner position,
The through-hole forming step is characterized in that a corner break line by a through-hole is formed at a corner portion where the side break line intersects in a direction inclined with the side break line.

  In the method for manufacturing a silicon nitride ceramics sintered substrate, it is preferable that the corner break line is formed to protrude toward the ear portion.

  In the method for manufacturing a silicon nitride ceramic sintered substrate, the angular break line has a protruding length protruding to the ear portion larger than a beam spot diameter of the laser used for forming the through hole and less than 3.5 mm. It is preferable.

  In the method of manufacturing a silicon nitride ceramic sintered substrate, the corner break line is preferably a slit formed by connecting a plurality of through holes.

  In the method for manufacturing a silicon nitride ceramic sintered substrate, a plurality of through holes in the corner break line and a plurality of scribe holes in the side break line are intermittently formed, and a pitch of the through holes in the corner break line is the side. The pitch is preferably smaller than the pitch of the scribe holes in the break line.

The method for producing a silicon nitride ceramic aggregate substrate of the present invention is a method for producing a silicon nitride ceramic aggregate substrate by adding an ear splitting step to the method for producing a silicon nitride ceramic sintered substrate,
The ear part dividing step is characterized in that the silicon nitride ceramic sintered substrate is divided into an ear part and a silicon nitride ceramic aggregate substrate along the side break line.

The silicon nitride ceramic aggregate substrate of the present invention is a rectangular silicon nitride ceramic aggregate substrate having a circuit forming portion and an edge portion for taking a large number of circuit boards, and having chamfered corners,
The pitch of the concave surface portion on the chamfered surface is smaller than the pitch of the concave surface portion on the side surface.

  According to the present invention, cracks and chips generated at the corners of the silicon nitride ceramic aggregate substrate are suppressed, so that the yield of manufacturing the silicon nitride ceramic aggregate substrate can be improved.

It is the schematic explaining the manufacturing method of the silicon nitride ceramic aggregate substrate which concerns on this invention. It is the schematic explaining the slit which concerns on FIG. It is the schematic explaining the other slit which concerns on this invention. It is the schematic explaining the corner break line which concerns on this invention. It is the schematic explaining the manufacturing method which concerns on a comparative example. It is the schematic explaining the manufacturing method which concerns on another comparative example.

  Embodiments of the present invention will be described in detail below, but the present invention is not necessarily limited thereto. The description regarding each embodiment is applicable also to other embodiment unless there is particular notice.

  The inventors of the present invention have a problem of the prior art, as for the sintered substrate as sintered, when splitting into the silicon nitride ceramic aggregate substrate and the ears, cracks and chips generated at the four corners of the silicon nitride ceramic aggregate substrate, As a result of intensive studies, the present inventors have arrived at the present invention in which a scribe hole and a through hole for division are formed in a silicon nitride ceramic sintered substrate.

A method for manufacturing a silicon nitride ceramic aggregate substrate according to the present invention will be described with reference to FIGS. 1 and 2, for example. As shown in FIG. 1 (1a), the silicon nitride ceramics sintered substrate 1 is formed using a carbon dioxide laser (CO ₂ laser) or the like along the outer edge 10 from the outer edge 10 to the inner side of the silicon nitride ceramics sintered substrate. By forming a plurality of scribe holes 13a (non-through holes), break lines 13 (hereinafter referred to as side break lines) are formed by dividing lines connecting the centers of the scribe holes (scribe hole forming step). Hereinafter, the “scribe hole” refers to a hole that does not penetrate the substrate (non-through hole).

  Next, a slit 14 penetrating in the thickness direction of the silicon nitride ceramic sintered substrate is formed so as to chamfer the corner in a direction inclined with the side break line 13 at a corner where the side break line 13 intersects (in other words, Through-hole forming step (more specifically, slit forming step)). In the following, “slit” refers to an elongated notch penetrating the substrate from one surface to the other surface. “Through hole” refers to a hole penetrating the substrate from one surface to the other surface. As shown in FIG. 2 (2b), the slit 14 is formed by connecting a plurality of through holes, and a break line 14 ′ (hereinafter referred to as a corner break line) by a dividing line connecting the centers of the through holes. ).

  Next, with respect to the four sides of the silicon nitride ceramic sintered substrate 1, the respective ear portions are bent in order, and a tensile stress due to bending is applied in a direction perpendicular to the side break line 13. The ear part 11 is divided (ear part dividing step). The obtained silicon nitride ceramic aggregate substrate 12 has a rectangular shape with four corners chamfered, as shown in FIG. 1 (1b).

  Next, in the copper circuit board forming step, a plurality of copper circuit boards 16 are joined to one surface of the silicon nitride ceramic aggregate substrate 12 (see FIG. 1 (1b)), and a plurality of copper heat sinks are joined to the other face. (Not shown), second break lines 18 and 18 ′ by second scribe holes are formed on the surface of the silicon nitride ceramic aggregate substrate 12 on the side where the circuit board 16 is joined.

  Thereafter, the silicon nitride ceramic aggregate substrate 12 is divided along the second break lines 18 and 18 ′ to separate the circuit forming portion (corresponding to the circuit substrate 20) and the edge portion 17, and each circuit substrate 20. Get. As shown in FIG. 1 (1 c), the circuit board 20 includes a copper circuit board 16, a copper heat sink (not shown), and a ceramic substrate part 19. Each of the above-mentioned patent documents relates to the formation of the second scribe hole and the second break line, and does not refer to the side break line and the corner break line.

  In the method for manufacturing a silicon nitride ceramic sintered substrate according to the present invention, for example, as shown in FIGS. 2 (2a) to (2c), in the direction in which the side break lines 13 intersect with each other, In other words, a corner break line 14 ′ is formed by the slit 14 connected to the through hole 14 a so as to chamfer the corner portion. Therefore, when the silicon nitride ceramics sintered substrate 1 is bent and divided into the silicon nitride ceramics aggregate substrate 12 and the ears 11, it is possible to suppress the occurrence of cracks and chips at the four corners of the silicon nitride ceramics aggregate substrate. it can.

  In the method for manufacturing a silicon nitride ceramic sintered substrate of the present invention, for example, as shown in FIGS. 4 (4a) to (4b), the through hole 34a of the corner break line and the scribe hole 13a of the side break line are intermittently formed. It is preferable that a plurality of holes are formed, and the pitch of the through holes 34a in the corner break line is smaller than the pitch of the scribe holes 13a in the side break line. When the pitch is changed in this way and the corner break lines 34 are more easily divided than the side break lines 13, the stress concentration is eased at the four corners of the silicon nitride ceramic aggregate substrate.

  In the method for producing a sintered silicon nitride ceramic substrate of the present invention, for example, as shown in FIGS. 2 (2b) to (2c), the corner break line 14 'is a slit 14 formed by connecting a plurality of through holes. It is preferable. By the slits penetrating the substrate, the stress concentration is particularly relaxed at the corners of the four corners of the silicon nitride ceramic aggregate substrate.

  When the above method for manufacturing a silicon nitride ceramic sintered substrate of the present invention is used, for example, as shown in FIG. 2 (2d), the pitch of the plurality of concave portions 14b on the chamfered surface 14c is equal to the plurality of concave portions 13b on the side surface 13c. This is preferable because a silicon nitride ceramics aggregate substrate having a pitch smaller than the above pitch can be obtained. Use of the slit leads to particularly alleviating the stress concentration at the corner portion where the side break line is intersected by the scribe hole. Therefore, in the silicon nitride ceramic aggregate substrate, for example, as shown in FIG. 4C, it is preferable that the plurality of concave surface portions 34b in the chamfered surface 34c are connected closer to each other.

  In the method for manufacturing a silicon nitride ceramic sintered substrate of the present invention, the scribe hole 13a has a diameter of, for example, 300 μm or less and a depth of, for example, 1/3 or more of the thickness of the silicon nitride ceramic aggregate substrate. The diameter of the scribe hole depends largely on the beam spot diameter of the laser used, but is preferably 30 to 200 μm, and more preferably 50 to 150 μm. The depth of the scribe hole is more preferably 80 to 300 μm, and still more preferably 100 to 250 μm, for example, when the substrate thickness is 0.32 mm. The pitch of the scribe holes is preferably not more than twice the diameter of the scribe holes, more preferably equal to the diameter of the scribe holes, and particularly preferably determined by the cleaving property when the substrate is divided. This pitch control can be adjusted by processing speed control, and may be interlocked with the number of laser output pulses.

  In the method for manufacturing a silicon nitride ceramic sintered substrate according to the present invention, for example, as shown in FIG. 2 (2c), slits 14 are formed at the corners where the side break lines by the scribe holes intersect and connect the through holes. For example, the slit width is 30 to 200 μm, and the slit length is 2.8 to 8.4 mm. The diameter or slit width of the through hole is more preferably 20 to 150 μm, and further preferably 30 to 100 μm. The length of the slit is more preferably 3.0 to 8.0 mm, still more preferably 3.5 to 7.5 mm. Moreover, the break line by a through-hole can make width | variety and length the same as a slit dimension.

  In the method for manufacturing a silicon nitride ceramic sintered substrate according to the present invention, the angular break line or slit formed by the through hole is inclined, for example, by 30 ° to 60 ° with respect to the side break line formed by the scribe hole. More specifically, it is preferable to tilt the side break line by, for example, 45 ° with respect to the scribe hole because the area of the substrate can be used effectively without waste.

  In the method for manufacturing a silicon nitride ceramic sintered substrate of the present invention, the scribe hole forming step may be performed after the through hole forming step, but it is more preferable to perform the through hole forming step after the scribe hole forming step. If it is the latter, since the intersection of the side break lines by the scribe hole can be used as a reference point for processing when forming the through hole or slit, the processing accuracy of the through hole or slit is improved.

In the method for manufacturing a silicon nitride ceramic sintered substrate according to the present invention, the scribe hole, the through hole or the slit is preferably formed by a laser. For example, a YAG laser or a carbon dioxide laser (CO ₂ laser) is used. Scribing by irradiation with a YAG laser or a carbon dioxide laser is suitable for intermittently forming deep holes.

  The diameter of the laser beam spot is equal to or smaller than the scribe hole diameter, the through hole diameter, or the slit width. When forming the holes, the pitch at which the beam spot is irradiated is the same as the pitch of the scribe holes and the pitch of the through holes described above. In the case of forming the slit, the irradiation is performed so that the beam spots are partially overlapped and connected, for example, by setting the pitch for irradiating the beam spots to 100 μm or less (more specifically, 30 μm or less, more specifically 20 μm or less).

  In the method for manufacturing a silicon nitride ceramic sintered substrate of the present invention, it is preferable that the laser beam spot scanning is repeated a plurality of times (for example, the beam spot scanning is repeated 10 times) in the through hole forming step. When the energy density to be irradiated is lowered by repeating scanning a plurality of times, cracks due to thermal shock are less likely to be formed on the surface (inner wall surface) of the through hole. , Leading to the suppression of crack growth and chipping.

  In the method for manufacturing a silicon nitride ceramic sintered substrate of the present invention, it is preferable that the corner break line protrudes from the ear portion. More preferably, the protruding length of the angular break line is larger than the beam spot diameter of the laser used for forming the slit and less than 3.5 mm.

  For example, as shown in FIGS. 2 (2b) to (2c), when the corner break line 14 'is constituted by the slit 14, if the protrusion length L1 is larger than the beam spot diameter of the laser, the silicon nitride ceramic aggregate substrate and the ear portion , The generation of burrs generated at the intersection of the side break lines adjacent to the slit can be suppressed. Further, when the silicon nitride ceramic aggregate substrate and the ear portion are divided, the corner portion can be prevented from remaining on the chamfered portion. If there are burrs on the sides of the silicon nitride ceramic aggregate substrate, it is preferable to suppress the generation of burrs since there is a risk of misalignment when performing alignment on the sides in the subsequent copper circuit board forming step. Further, when the slit protrusion length L1 is 3.5 mm or more, when dividing the silicon nitride ceramics aggregate substrate and the ear portion, the ear portion is easily divided on the extension line of the slit, and the man-hour for the removal work increases. This is because the processing time becomes longer and it becomes uneconomical.

  For example, as shown in FIGS. 4 (4 a) to (4 b), when the angular break line is composed of intermittently formed through holes, if the protruding length L 2 is larger than the beam spot diameter of the laser, the silicon nitride ceramics aggregate substrate When the ears are divided, the generation of burrs generated at the intersections of the side break lines 13 adjacent to the corner break lines 34 can be reduced. In addition, when dividing | segmenting into a silicon nitride ceramic aggregate substrate and an ear | edge part, for example, when a triangular corner | angular part remains in a chamfering part, it is preferable to remove separately. Further, when the protrusion length L2 of the corner break line is set to 3.5 mm or more, when the silicon nitride ceramic aggregate substrate and the ear portion are divided, the ear portion is likely to be divided on the extension line of the slit, and the man-hour for the removal work is increased. In addition, the processing time becomes longer and it becomes uneconomical.

The silicon nitride ceramic sintered substrate and the silicon nitride ceramic aggregate substrate according to the present invention have a thickness of 0.2 mm to 1.0 mm, for example. More specifically, the thickness is set to 0.25 mm to 0.65 mm, for example. In the silicon nitride ceramic sintered substrate and the silicon nitride ceramic aggregate substrate according to the present invention, the fracture toughness value is, for example, 5.0 MPa · m ^1/2 or more. More specifically, the fracture toughness value is set to, for example, 5.0 to 7.5 MPa · m ^1/2 .

  The above prior arts (Patent Documents 1 and 2) are not related to a technique for manufacturing a silicon nitride ceramics aggregate substrate from a silicon nitride ceramics sintered substrate, but are diamond-shaped at the intersection of the break lines with respect to the silicon nitride ceramics sintered substrate. Since a large number of shapes or triangular cutout portions are formed, the volume of the cutout is large. By thinning, the residual stress of the silicon nitride ceramic sintered substrate is relaxed, and the warp of the silicon nitride ceramic sintered substrate is reduced. However, if the amount of warpage of the silicon nitride ceramic sintered substrate changes before and after the formation of the cut-out portion, misalignment may occur when alignment is performed on the side of the silicon nitride ceramic sintered substrate or a specific marking. is there.

  On the other hand, in the method for manufacturing a silicon nitride ceramic sintered substrate of the present invention, the corner break line or slit formed by the through hole formed at the corner portion where the side break line formed by the scribe hole intersects is narrower than the length thereof. For this reason, deformation such as warpage of the silicon nitride ceramic sintered substrate is suppressed as compared with the shape of the diamond-shaped or triangular cut-out portion. In addition, misalignment is unlikely to occur when alignment is performed on the side of the silicon nitride ceramics sintered substrate or specific marking.

  Hereinafter, the present invention will be specifically described based on examples. In addition, this invention is not necessarily limited to the following Example.

Example 1
In the raw material for forming silicon nitride ceramics, a silicon nitride powder is used as a main raw material, and 2% by mass of MgO and 3% by mass of Y ₂ O ₃ are used as sintering aids. Sintering was performed at a maximum temperature of 1850 ° C. for 5 hours in an atmosphere to produce a silicon nitride ceramic sintered substrate 1 having a thickness of 0.32 mm, a length of 150 mm, and a width of 200 mm and a rectangle. A side break line 13 by scribe holes 13a was formed along the outer edge 10 from the outer edge 10 of the silicon nitride ceramics sintered substrate 1 to the inner position using a carbon dioxide laser (scribing hole forming step). The scribe holes 13a have a maximum diameter of 50 μm, a depth of 150 μm, and a pitch of 100 μm on the substrate surface. As shown in FIG. 1 (1a), side break lines 13 are formed along the four sides by the scribe holes 13a. . The width of the ear portion 11 was 5 mm.

Subsequently, using a carbon dioxide laser (output: 100 W), the laser beam spot is scanned once, and the side break lines 13 and 45 are respectively formed at the corners (four places) where the side break lines 13 intersect with the scribe holes 13a. The slit 14 formed by connecting the through holes was formed by continuously forming the through holes from the position protruding by L1 in the tilting direction (slit forming step).
Laser beam spot diameter = 0.07 mm
Processing speed = 15mm / s
Slit protrusion length L1 = 0.7mm
Overall length of slit = 4.2mm
Slit width on substrate surface = 0.10 mm

  Focusing on the lower left part in the silicon nitride ceramic aggregate substrate 12 of FIG. 1 (1a) of Example 1, the state in the vicinity of the slit 14 is shown in FIG. 2 (2a), and the state of irradiating the laser spot is shown in FIG. 2 (2b). Enlarged to show. That is, the side break line 13 was formed by forming a plurality of scribe holes 13 a in a line on the surface of the silicon nitride ceramic sintered substrate 1. At the corner where the side break lines 13 intersect by the scribe hole 13a, the laser spot is irradiated while shifting the position in a direction inclined by 45 ° with the side break line 13, and a plurality of through holes 14a are overlapped to form a corner break. By forming a line 14 ', a slit 14 penetrating the substrate was formed as shown in FIG. 2 (2c). The inner wall of the slit 14 has a plurality of concave surface portions 14b derived from the through holes, and the pitch of the concave surface portions 14b is smaller than the pitch of the scribe holes 13a.

  The silicon nitride ceramic sintered substrate 1 according to FIG. 1 (1 a) was bent and divided by a side break line 13 to be divided into a silicon nitride ceramic aggregate substrate 12 and an ear portion 11. A plurality of silicon nitride ceramics sintered substrates 1 are formed, and the sample corresponding to the chamfered surface and the side surface of the silicon nitride ceramic aggregate substrate is observed with a laser microscope for a sample obtained by dividing the ears from five of them. did. There were no cracks, burrs, and cracks (0%) on the side surfaces (laser processed surface and fractured surface) adjacent to the chamfered surface of the silicon nitride ceramic aggregate substrate. Moreover, since the corner | angular part 15 was isolate | separated in the state attached to the ear | edge part, it was not produced | generated as a single end material.

  As shown in FIG. 2 (2d), the silicon nitride ceramic aggregate substrate 12 obtained by dividing and removing the ears from the silicon nitride ceramic sintered substrate has a pitch of the chamfered concave portions 14b of the side surfaces (the ears of the ears). The pitch is smaller than the pitch of the concave surface portions 13b derived from the scribe holes 13a in the side surface formed by separation. In this configuration, when the ear portion was divided, the stress concentration was eased at the corner portion, so that no crack or chip was formed between the chamfered surface and the side surface.

A brazing material was applied to the silicon nitride ceramic aggregate substrate 12 by a screen printing method. For the brazing material, 0.3 part by mass of TiH ₂ is added to an alloy powder composed of 70% by mass of Ag, 3% by mass of In, and 27% by mass of Cu (total 100 parts by mass), and further an organic solvent. The paste was prepared by adding an organic binder and kneading. After drying the silicon nitride ceramic aggregate substrate coated with the brazing material, a copper plate of 0.3 mm is placed in contact with the front side and the back side, respectively, and heat-treated in vacuum at 800 ° C. for 20 minutes while applying pressure. And a joined body of a copper plate (which becomes a circuit board and a heat radiating plate). Between the silicon nitride ceramic aggregate substrate and the copper plate, a brazing material layer having a thickness of about 30 μm is formed.

  On the copper plate of the obtained joined body, an etching resist ink curable with ultraviolet rays was applied, and then the etching resist ink was cured by irradiating with ultraviolet rays to form a resist film pattern. As this etching resist ink, an alkali peeling type ink was used.

  Etching with a copper chloride base etchant (mixed solution containing copper chloride, hydrochloric acid and hydrogen peroxide) maintained at 30 ° C., and an unnecessary copper plate outside the pattern of the circuit board or heat sink (ie, coated with a resist film) The portion of the copper plate that has not been removed) was removed.

  Next, in order to remove the portion where the brazing material protrudes from the copper plate (the protruding portion of the brazing material), the first brazing material etching treatment (with an acidic solution containing carboxylic acid and / or carboxylate salt and hydrogen peroxide) Etching treatment) and second brazing material etching treatment (etching treatment with a solution containing ammonium hydrogen fluoride and hydrogen peroxide) were sequentially performed to remove the protruding portion of the brazing material.

  Subsequently, the joined body was immersed in a 3% by mass aqueous sodium hydroxide solution to remove the resist film. Subsequently, after chemical polishing and cleaning with ion-exchanged water, Ni plating was applied to the front side copper plate (circuit board) and the back side copper plate (heat radiating plate). This chemical polishing was performed using a sulfuric acid-based general commercial solution for the purpose of gloss treatment.

  In this manner, an assembly of circuit boards in which a plurality of sets of Ni-plated copper circuit board 16 and copper heat sink (not shown) were joined was obtained. Next, the second break lines 18 and 18 'are formed by the scribe holes, and the edges 17 on the four sides are divided so that the copper circuit board 16 and the copper heat sink (see FIG. 1C). A plurality of circuit boards 20 having a ceramic substrate portion 19 and a ceramic substrate portion 19 were obtained.

(Example 2)
1 except that the slit 14 of FIG. 1 was changed to the slit 24 of FIG. The slit 24 is obtained by shortening the entire length of the slit 14 by setting the slit protrusion length L1 = 0 mm. When the obtained silicon nitride ceramic sintered substrate is bent and divided by the side break line 13 to be divided into the silicon nitride ceramic aggregate substrate and the ears, the side surface adjacent to the chamfered surface of the silicon nitride ceramic aggregate substrate (laser processed surface and In this example, no cracks or cracks occurred in the fracture surface. In addition, the pitch of the plurality of concave portions on the chamfered surface is smaller than the pitch of the plurality of concave portions on the side surface. However, in the silicon nitride ceramic aggregate substrate 12, the rate at which burrs exceeding the tolerance were formed in the vicinity of the chamfered side surface was 2%. A plurality of sets of copper circuit boards and copper heat sinks were formed on the silicon nitride ceramic aggregate substrate on which no burrs were formed, and divided to obtain a circuit board similar to that of Example 1. In Example 2, the rate at which burrs are formed is 2% (yield 98%), but this is not a problem.

(Example 3)
In Example 3, the slit 14 in FIG. 1 was changed to the angular break line 34 by the through holes in FIG. 4 (4a), and the pitch of the scribe holes 13a was changed. Other conditions were the same as in Example 1. That is, the side break line 13 was formed by forming a plurality of scribe holes 13 a in a line on the surface of the silicon nitride ceramic sintered substrate 1. At the corner where the side break line 13 intersects, a laser spot is irradiated at an interval in a direction inclined by 45 ° with respect to the side break line 13, and a plurality of through holes 34a are formed as shown in FIG. A corner break line 34 was formed. Here, L2 = L1. The pitch of the through holes 34a, that is, the pitch of irradiating the beam spot was set to 150 μm. The side break line 13 formed by the scribe holes 13a has a beam spot irradiation pitch of 200 μm.

  When the silicon nitride ceramic sintered substrate is bent and divided by the side break line 13 to be divided into the silicon nitride ceramic aggregate substrate 12 and the ear portion 11, a side surface (laser processed surface) adjacent to the chamfered surface 34c of the silicon nitride ceramic aggregate substrate 12 is obtained. In addition, no cracks and cracks occurred in the fracture surface). As shown in FIG. 4 (4 c), the silicon nitride ceramic aggregate substrate 12 has a plurality of concave surface portions 13 b (a concave surface portion derived from the through hole 34 a) on the chamfered surface 34 c. It is smaller than the pitch of the concave surface portion derived from the scribe holes 13a. However, in the silicon nitride ceramic aggregate substrate 12, the rate at which burrs exceeding the tolerance were formed in the vicinity of the chamfered side surface was 4%. A plurality of sets of copper circuit boards and copper heat sinks were formed on the silicon nitride ceramic aggregate substrate on which no burrs were formed, and divided to obtain a circuit board similar to that of Example 1. In Example 3, the rate of burr formation was 4% (yield 96%), but this is an acceptable range for manufacturing yield.

(Comparative Example 1)
As shown in FIG. 5 (5a), a corner break line 114 is formed by a scribe hole (non-through hole) instead of the slit of FIG. Was formed diagonally (that is, the slit forming step was changed to a chamfering scribe hole forming step), and the same procedure as in Example 1 was performed.

  The manufacturing method of Comparative Example 1 is basically the same as that of Example 1, except that a scribe hole forming step for dividing the silicon nitride ceramic aggregate substrate 112 and the ear portion 111 and a chamfered scribe hole forming step are performed. It was supposed to be prepared. In the scribe hole forming step, the side break line 113 of the scribe hole 1113a was formed along the outer edge from the outer edge of the silicon nitride sintered substrate 101 to the inner position. In the chamfering scribe hole forming step, a corner break line 114 is formed by chamfering scribe holes in a direction inclined by 45 ° with the side break line 113 at a corner where the side break line 113 of the scribe hole formed by the scribe hole forming step intersects. It was supposed to be. Through these steps, a silicon nitride ceramics sintered substrate 101 according to FIG. 5 (5a) was produced.

  After the silicon nitride ceramic sintered substrate 101 of Comparative Example 1 was bent and divided into the silicon nitride ceramic aggregate substrate 112 and the ear portion 111, the remaining triangular corner portion 115 was bent and divided to be removed. Burr and cracks did not occur on the side surfaces (laser machined surface and fractured surface) adjacent to the chamfered surface of the silicon nitride ceramic aggregate substrate, but as shown in the silicon nitride ceramic aggregate substrate 112 ′ in FIG. 5 (5b). The ratio of formation of cracks 134 and 136 was 8% (yield 92%). The yield was lower than that of the example (target yield: 95% or more).

(Comparative Example 2)
As shown in (6a) of FIG. 6, the same procedure as in Example 1 was performed except that the slit forming step was not performed.

  The manufacturing method of Comparative Example 2 is basically the same as that of Example 1, except that the outer edge of the silicon nitride sintered substrate 201 is used as a scribe hole forming step for dividing the silicon nitride ceramic aggregate substrate 212 and the ears 211. A side break line 213 is simply formed by a scribe hole 213a along the outer edge at a position on the inner side. Through this step, a silicon nitride ceramic sintered substrate 201 according to FIG. 6 (6a) was produced.

  When the silicon nitride ceramic sintered substrate of Comparative Example 2 is bent and divided into the silicon nitride ceramic aggregate substrate 212 and the ears 211, burrs are generated on the side surfaces (laser processed surface and fracture surface) of the silicon nitride ceramic aggregate substrate. However, the ratio of formation of cracks and chips was 8%. Furthermore, the ratio of the formation of cracks (the cracked corners 238 were separated) as shown in FIG. 6 (6b) in the silicon nitride ceramic aggregate substrate 212 was 3%. The production yield was considerably lower than that of the example (yield 89%), and it was judged that it was not suitable for mass production.

1: silicon nitride ceramic sintered substrate, 10: outer edge,
11: Ear part, 12: Silicon nitride ceramic aggregate substrate,
13: Side break line, 13a: Scribe hole,
13b: concave portion on the side surface, 13c: side surface,
14: slit, 14 ': corner break line,
14a: a through hole, 14b: a concave portion of a chamfered surface, 14c: a chamfered surface,
15: Triangular corner,
16: Copper circuit board, 17: Edge,
18, 18 ′: second break line,
19: Ceramic substrate part, 20: Circuit board,
24: slit,
34: Square break line, 34a: Through hole,
34b: concave portion of the chamfered surface, 34c: chamfered surface,
101: Sintered silicon nitride ceramic substrate, 111: Ear part,
112, 112 ': Silicon nitride ceramics aggregate substrate,
113: Side break line, 113a: Scribe hole,
114: Corner break line, 115: Triangular corner,
134: crack, 136: crack,
201: Sintered silicon nitride ceramic substrate 211: Ear part
212: Silicon nitride ceramic aggregate substrate,
213: Side break line, 213a: Scribe hole,
238: Broken corner

Claims (6)

A silicon nitride ceramic aggregate substrate having a circuit forming portion and an edge portion for taking a large number of circuit boards from a rectangular silicon nitride ceramic sintered substrate having ears around the silicon nitride ceramic aggregate substrate A method of manufacturing a silicon nitride ceramic sintered substrate,
A scribe hole forming step for dividing the silicon nitride ceramic aggregate substrate and the ear portion, and a through hole forming step,
The scribe hole forming step forms a side break line by the scribe hole along the outer edge from the outer edge of the silicon nitride ceramic sintered substrate to the inner position,
The through hole forming step forms a corner break line by a through hole in a direction inclined with the side break line at a corner portion where the side break line intersects ,
The method for manufacturing a silicon nitride ceramics sintered substrate, wherein the corner break line is a slit formed by connecting a plurality of through holes . A silicon nitride ceramic aggregate substrate having a circuit forming portion and an edge portion for taking a large number of circuit boards from a rectangular silicon nitride ceramic sintered substrate having ears around the silicon nitride ceramic aggregate substrate A method of manufacturing a silicon nitride ceramic sintered substrate,
A scribe hole forming step for dividing the silicon nitride ceramic aggregate substrate and the ear portion, and a through hole forming step,
The scribe hole forming step forms a side break line by the scribe hole along the outer edge from the outer edge of the silicon nitride ceramic sintered substrate to the inner position,
The through hole forming step forms a corner break line by a through hole in a direction inclined with the side break line at a corner portion where the side break line intersects,
The plurality of through holes in the corner break line and the scribe holes in the side break line are intermittently formed, and the pitch of the through holes in the corner break line is smaller than the pitch of the scribe holes in the side break line. A method for producing a silicon nitride ceramics sintered substrate, characterized in that: 3. The method of manufacturing a silicon nitride ceramics sintered substrate according to claim 1, wherein the corner break line is formed so as to protrude toward the ear part. 4. The nitriding according to claim 3 , wherein the angular break line has a protrusion length protruding from the ear portion larger than a beam spot diameter of a laser used for forming the through hole and less than 3.5 mm. Manufacturing method of silicon ceramic sintered substrate. A method for producing a silicon nitride ceramic sintered substrate according to any one of claims 1 to 4, a further method for producing a silicon nitride ceramic assembled board by adding ears dividing step,
The method of manufacturing a silicon nitride ceramic aggregate substrate, wherein the ear portion dividing step divides the silicon nitride ceramic sintered substrate into an ear portion and a silicon nitride ceramic aggregate substrate along the side break line. A rectangular silicon nitride ceramic aggregate substrate having a circuit forming portion and an edge for taking a large number of circuit boards, and having chamfered corners,
A silicon nitride ceramics aggregate substrate, wherein the pitch of the plurality of concave portions on the chamfered surface is smaller than the pitch of the plurality of concave portions on the side surface.

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