JP2021048164A - Silicon nitride ceramics sintered substrate, method for manufacturing the same, silicon nitride ceramics assembly substrate, and method for manufacturing circuit board - Google Patents

Abstract

To provide a silicon nitride ceramics sintered substrate, a method for manufacturing the same, a silicon nitride ceramics assembly substrate, and a method for manufacturing a circuit board, for suppressing a misalignment between the center of a metal plate on a front surface side and the center of the metal plate on a back surface side.SOLUTION: A silicon nitride ceramics sintered substrate for manufacturing a silicon nitride ceramics assembly substrate having a circuit forming portion and an edge portion for taking out a large number of circuit boards from a rectangular silicon nitride ceramics sintered substrate 1 having an ear portion 11 around the silicon nitride ceramics assembly substrate 12 includes a scribe hole 13a for dividing the silicon nitride ceramic assembly substrate and the ear portion, and a through-hole 5 for positioning. The scribe hole forms a side break line 13 based on the scribe hole along an outer edge from an outer edge position of the silicon nitride ceramics sintered substrate to an inner position of the silicon nitride ceramics sintered substrate. The through-hole for positioning is formed inside the side break line.SELECTED DRAWING: Figure 1

Description

The present invention relates to a silicon nitride ceramics sintered substrate and a method for manufacturing the same, a silicon nitride ceramics assembly substrate, and a method for manufacturing a circuit board for taking a large number of circuit boards.

For circuit boards used for semiconductor modules, power modules, etc., ceramic substrates for circuits are used in terms of thermal conductivity, insulation, strength, etc., and metal circuit boards such as Cu and Al can be used as the ceramic substrates for circuits. A metal radiator plate is joined to form a circuit board. Alumina material has been widely used as a ceramic substrate for circuits, but recently, silicon nitride, which has high strength and improved thermal conductivity, has been used so that it can be used even in a harsher environment. ..

In addition, as a technique for mass-producing circuit boards, a metal plate such as a Cu plate is bonded to a single ceramic assembly substrate having a size capable of cutting out a large number of the circuit board ceramic substrates by an active metal brazing method or a direct bonding method. There is a method in which a metal circuit board and a metal heat dissipation plate are formed by etching or the like, and the ceramic assembly substrate is divided into predetermined sizes to obtain individual circuit boards.

As a method of dividing into individual circuit boards, for example, a recess or a groove is formed in the ceramic assembly substrate by laser processing before joining the Cu plate or the like, and the ceramic assembly substrate is bent after the Cu plate or the like is joined. , A method of dividing by a recess or a groove is adopted.

The present inventor forms scribe holes (non-penetrating holes) for division in a sintered plate as it is sintered by laser processing, and divides (cuts) the scribe holes by dividing lines to sinter. When the ceramic assembly substrate was prepared by removing the four sides of the plate, it was found that burrs were likely to occur on the edges of the ceramic assembly substrate. Then, in the process of manufacturing a circuit board, even if the alignment is performed with reference to the edge, it is difficult to manufacture the metal plate such as a Cu plate so that the center of the metal plate is located at the center of the circuit board. There is a problem that the center of the metal plate and the center of the metal plate on the back surface side are misaligned, and the pass rate of the circuit board is lowered.

Patent Document 1 (Japanese Patent Laid-Open No. 2008-198905) and Patent Document 2 (Japanese Patent Laid-Open No. 2017-28192) disclose a technique for dividing a circuit board from a ceramic assembly substrate by a scribing hole or a dividing groove.

Japanese Unexamined Patent Publication No. 2008-198905 JP-A-2017-28192

The conventional technique has not solved the problem that the center of the metal plate on the front surface side and the center of the metal plate on the back surface side may be misaligned. If the center of the metal plate on the front surface side and the center of the metal plate on the back surface side are largely misaligned, the thermal resistance in the circuit board may increase.

An object of the present invention is to prevent the center of the metal plate on the front surface side and the center of the metal plate on the back surface side from being displaced from each other. It is an object of the present invention to provide a method for manufacturing a ceramic assembly substrate and a circuit board.

The silicon nitride ceramics sintered substrate of the present invention has a circuit forming portion and an edge portion for taking a large number of circuit boards from a rectangular silicon nitride ceramics sintered substrate having ears around the silicon nitride ceramics assembly substrate. It is a silicon nitride ceramics sintered substrate for manufacturing a silicon nitride ceramics assembly substrate which has.
It is provided with a scribe hole for dividing the silicon nitride ceramic assembly substrate and the selvage portion, and a through hole for positioning.
The scribe holes form a side break line by the scribe holes along the outer edge at a position inside from the outer edge of the silicon nitride ceramics sintered substrate.
The positioning through hole is formed inside the side break line.

The silicon nitride ceramics assembly substrate of the present invention is a silicon nitride ceramics assembly substrate having a circuit forming portion and an edge portion for taking a large number of circuit boards, and is used for positioning inside the side of the silicon nitride ceramics assembly substrate. It is characterized in that a through hole is formed.

The method for manufacturing a silicon nitride ceramics sintered substrate of the present invention has a circuit forming portion and an edge for taking a large number of circuit boards from a rectangular silicon nitride ceramics sintered substrate having an ear portion around the silicon nitride ceramics assembly substrate. A method for manufacturing a silicon nitride ceramics sintered substrate for manufacturing a silicon nitride ceramics sintered substrate having a portion.
A scribe hole forming step for dividing the silicon nitride ceramic assembly substrate and the selvage portion and a through hole forming step for positioning are provided.
In the scribe hole forming step, a side break line due to the scribe holes is formed along the outer edge at a position inside from the outer edge of the silicon nitride ceramics sintered substrate.
The positioning through hole forming step is characterized in that a through hole is formed inside the side break line.

In the silicon nitride ceramics sintered substrate, it is preferable that at least two through holes are formed in the vicinity of the corners of the silicon nitride ceramics assembly substrate, and it is more preferable that each of the through holes is formed in the vicinity of the four corners. The through hole can be used as a common positioning reference for the front surface (circuit side) and the back surface (heat dissipation side) of the silicon nitride ceramics sintered substrate.

In the silicon nitride ceramics sintered substrate, the center point obtained from at least two through holes formed in the vicinity of the corner of the silicon nitride ceramics assembly substrate coincides with the center point of the silicon nitride ceramics assembly substrate. It is preferable to have. Further, the silicon nitride ceramics sintered substrate (having a through hole for positioning) can be removed from the ear portion to obtain a silicon nitride ceramics assembly substrate. Further, in the silicon nitride ceramics sintered substrate, the center point of the front surface obtained from at least two through holes formed in the vicinity of the corners of the silicon nitride ceramics assembly substrate, and the back surface obtained from the through holes. It is preferable that the center point coincides with the center point. Further, in the silicon nitride ceramic assembly substrate, the center point of the front surface obtained from at least two through holes formed in the vicinity of the corner coincides with the center point of the back surface obtained from the through hole. Is preferable.

In the silicon nitride ceramics sintered substrate and the silicon nitride ceramics assembly substrate, it is preferable that the through holes have a circular opening shape.

In the silicon nitride ceramics sintered substrate, the distance between the side break line and the through hole is preferably 0.1 to 4.0 mm. In the silicon nitride ceramics assembly substrate, the distance between the side (corresponding to the side break line) of the silicon nitride ceramics assembly substrate and the through hole is preferably 0.1 to 4.0 mm.

The circuit board manufacturing method of the present invention manufactures a circuit board by adding a step of providing a metal plate on the circuit side and a step of providing a metal plate on the heat dissipation side to the manufacturing method of the silicon nitride ceramics sintered substrate. It ’s a method,
It is characterized in that one opening of the through hole is used when positioning the center point of the metal plate on the circuit side, and the other opening of the through hole is used when positioning the center point of the metal plate on the heat dissipation side. And.

Further, the method for manufacturing a circuit board of the present invention includes a step of manufacturing a silicon nitride ceramics assembly substrate having a circuit forming portion and an edge for taking a large number of circuit boards, and the inside of the side of the silicon nitride ceramics assembly substrate. Has a step of forming a through hole for positioning in
The silicon nitride ceramics assembly substrate includes a step of providing a metal plate on the circuit side and a step of providing a metal plate on the heat dissipation side.
It is characterized in that one opening of the through hole is used when positioning the center point of the metal plate on the circuit side, and the other opening of the through hole is used when positioning the center point of the metal plate on the heat dissipation side. And.

In the method for manufacturing a circuit board,
When the first pattern of the resist is provided on the metal plate for the circuit side, the center point of the first pattern is determined by the center of one opening of the through hole.
When the second pattern of the resist is provided on the metal plate for heat dissipation, the center point of the second pattern is determined by the center of the other opening of the through hole.

The silicon nitride ceramics sintered substrate of the present invention, the manufacturing method thereof, and the manufacturing method of the circuit board suppress the misalignment between the center of the metal plate on the front surface side and the center of the metal plate on the back surface side. Therefore, the pass rate of the circuit board can be improved.

It is the schematic explaining the silicon nitride ceramics sintered substrate which concerns on this invention. It is the schematic explaining the silicon nitride ceramics assembly substrate obtained from the substrate of FIG. It is the schematic which formed the 2nd break line on the substrate of FIG. It is the schematic which the brazing material was applied to the substrate of FIG. 3, (4a) shows the front surface and (4b) shows the back surface. It is the schematic which the Cu plate of the original plate was arranged and brazed on the substrate of FIG. 4, (5a) shows the front surface and (5b) shows the back surface. FIG. 5 is a schematic view in which the original Cu plate is patterned on the substrate of FIG. 5 and the protruding brazing material layer is removed. (6a) shows the front surface and (6b) shows the back surface. It is the schematic of the circuit board obtained from the board of FIG. It is the schematic which applied the brazing material to the substrate of FIG. It is the schematic which arranged the Cu plate of the original plate on the substrate of FIG. 8 and brazed. It is the schematic which patterned the Cu plate of the original plate with the substrate of FIG. It is the schematic which removed the brazing material layer exposed in the substrate of FIG. It is the schematic which formed the 2nd break line in the substrate of FIG. (A) is a cross-sectional view of the through hole in FIG. 1 and the like, and (b) is a cross-sectional view of another form related to the through hole. It is the schematic explaining another silicon nitride ceramics sintered substrate which concerns on this invention. It is a schematic diagram derived from the substrate of FIG. 14, in which the original Cu plate is arranged and brazed. It is the schematic explaining another silicon nitride ceramics sintered substrate which concerns on this invention. It is a schematic diagram derived from the substrate of FIG. 16 and in which the original Cu plate is arranged and brazed.

Embodiments of the present invention will be described in detail below, but the present invention is not necessarily limited thereto. The description of each embodiment can be applied to other embodiments unless otherwise specified.

As a result of diligent studies on the silicon nitride ceramics sintered substrate obtained by sintering in order to suppress the positional deviation when a metal plate such as a Cu plate is provided on the silicon nitride ceramics assembly substrate, the inventor has made silicon nitride ceramics. We came up with the present invention of providing a through hole for positioning in a sintered substrate or a silicon nitride ceramic assembly substrate.

(Embodiment 1)
The silicon nitride ceramics sintered substrate according to the present invention is shown in FIG. 1, and the manufacturing method thereof and the manufacturing method of the circuit board will be described with reference to FIGS. 1 to 7. First, as shown in FIG. 1, the silicon nitride ceramics sintered substrate 1 obtained by sintering is subjected to an outer edge at a position inside from the outer edge 10 of the silicon nitride ceramics sintered substrate by using a _{carbon dioxide gas laser (CO 2 laser) or the like.} By forming a plurality of scribe holes 13a (non-penetrating holes) along No. 10, a break line 13 (hereinafter referred to as a side break line) formed by a dividing line connecting the centers of the scribe holes is formed (scribing hole forming step). .. In the following, "scribe hole" refers to a hole that does not penetrate the substrate (a non-penetrating hole).

Then, a slit 14 is formed at the corner where the side break lines 13 intersect in the direction inclined from the side break line 13 so as to chamfer the corners in the thickness direction of the silicon nitride ceramics sintered substrate 1. (Through hole forming step for chamfering (more specifically, slit forming step)). In the following, "slit" refers to an elongated notch that penetrates a substrate from one side to the other. “Chamfering through hole” refers to a hole that penetrates a substrate from one surface to the other. The slit 14 is formed by connecting a plurality of through holes, and constitutes a break line 15 (hereinafter, referred to as an angular break line) formed by a dividing line connecting the centers of the through holes. The corner break line 15 may intersect the side break line and project from the side break line with a length L2. The length L2 is preferably larger than the beam spot diameter of the laser used for forming the slit and less than 3.5 mm. Although the angular break line is formed in the first embodiment, it is also possible to form a form in which the angular break line is not provided.

The long side of the four sides constituting the outer edge 10 of the silicon nitride ceramics sintered substrate is the long side, and the side break line 13 formed along the long side is inside (with the outer edge 10). Is a predetermined distance L1 on the opposite side) to form a through hole 5 for positioning (through hole forming step for positioning). Since there are two side break lines along the long side and one through hole 5 is formed near the corner break line 15, the silicon nitride ceramics sintered of the present invention having a total of four through holes 5 for positioning. A substrate is obtained (the distance between the side break line 13 and the positioning through hole 5 is L1). The diameter of the through hole 5 for positioning is preferably 100 to 500 μm, more preferably 150 to 300 μm. The distance L1 is preferably 0.1 to 4.0 mm, more preferably 0.2 to 3.0 mm, and even more preferably 0.5 mm to 2.0 mm. The reason why the numerical range is defined in this way is that if L1 is too small, the through hole 5 for positioning may come into contact with the side break line, and when the through hole is provided near the side break line, the substrate strength This is because there is a risk that it will lead to a decrease in. Further, if L1 is too large, the width of the allowance (corresponding to the second ear portion) for providing the through hole for positioning becomes large, the area of the ceramics portion in the circuit board becomes relatively small, and the circuit board becomes large. The number of takes is reduced.

Next, with respect to the four sides of the silicon nitride ceramics sintered substrate 1, each ear portion is bent in order, and tensile stress due to bending is applied in a direction perpendicular to the side break line 13, so that the four sides of the silicon nitride ceramics sintered substrate 1 are bent. The selvage portion 11 is divided (ear portion division step). As shown in FIG. 2, the obtained silicon nitride ceramics assembly substrate 12a penetrates for positioning near the chamfered corners of the four corners and at a predetermined distance L1 from the side break line 13. It has a hole 5.

Then, as shown in FIG. 3, second break lines 18, 18'by the second scribe holes are formed on the surface of the silicon nitride ceramics assembly substrate 12a. The second break line 18 is formed along the side break line 13, and the distance between the side break line 13 and the second break line 18 is larger than the distance L1. The through hole 5 is located at a position corresponding to the second ear portion. For example, the two second break lines 18'are formed so as to intersect the midpoints of, for example, the four second break lines 18. In the silicon nitride ceramics assembly substrate, diagonal lines can be drawn and the intersection of the diagonal lines can be obtained as the center point of the silicon nitride ceramics assembly substrate.

Then, as shown in FIG. 4A, in the front surface (surface) of the substrate of FIG. 3, the regions separated by the second break lines 18, 18'(in FIG. 4, each of the four regions). The brazing filler metal 16a is arranged by applying the brazing filler metal paste by screen printing. Further, the wax material 16a'is arranged by inverting the front and back surfaces of the substrate and applying the wax material paste on the back surface by screen printing.

Then, as shown in (5a) of FIG. 5, the original Cu plate 16b is provided so as to cover the brazing material 16a at four locations on the front surface (surface) of the substrate of FIG. Further, the substrate is inverted, and another original Cu plate 16b'is provided on the back surface so as to cover the four brazing materials 16a'. Then, the brazing materials 16a and 16a'are made into brazing materials by heat-treating the laminated body in which the Cu plate 16b'/ brazing material 16a' / silicon nitride ceramics assembly substrate (12a) / brazing material 16a / Cu plate 16b are laminated in this order. Braze as a layer.

When the Cu plate 16b or the Cu plate 16b'is provided, the position is adjusted so as not to cover at least the through hole 5. This is because if the through hole 5 for positioning is covered and cannot be seen, it cannot be used for positioning the resist pattern in a later process. To adjust the positions of the Cu plate 16b and the Cu plate 16b', for example, prepare a pair of pins or stoppers as jigs, and bring one pin or stopper into contact with one side of the Cu plate 16b to make Cu. A technique is used in which the other pin or stopper is brought into contact with the side adjacent to the plate 16b.

Then, using an image analysis device or the like, the centers of the respective positioning through holes 5 are calculated on the front surface, and from the four centers related to the positioning through holes 5, the silicon nitride ceramic assembly substrate (12a) Calculate the first center point of. Based on the first coordinates of the silicon nitride ceramics assembly substrate obtained by the "four centers" and the "first center point", a method of forming a photoresist or a method of attaching a resist film is used to form a Cu plate 16b. Four resist patterns are formed on the surface. The outline and position of the resist pattern can be determined by the above-mentioned first coordinates. Of the four centers, a connection (virtual line) connecting the upper right and lower left centers and a connection (virtual line) connecting the lower right and upper left centers are drawn, and the intersection of the two connections is the first. It may be calculated as the center point.

Further, the front and back surfaces of the substrate are inverted, the centers are calculated by the respective positioning through holes 5 on the back surface, and the silicon nitride ceramics assembly substrate (12a) is formed from the four centers related to the positioning through holes 5. Calculate the second center point of. Based on the second coordinates of the silicon nitride ceramics assembly substrate obtained by the "four centers" and the "second center point", a method of forming a photoresist or a method of applying a resist film is used to form a Cu plate 16b. Form four resist patterns in'. The outline and position of the resist pattern can be determined by the second coordinates. By using the same four through holes 5 on the front surface and the back surface (using them as a common positioning reference), the first and second coordinates can be shared, or the first center point can be used. And the second center point can be matched, and the positions of the resist patterns facing each other across the silicon nitride ceramic assembly substrate can be accurately aligned so as to overlap when viewed through.

Then, the Cu plate 16b and the Cu plate 16b'are patterned by an etching process, and the brazing material layer protruding outward from the edge of the Cu plate is removed by selective etching, as shown in FIG. 6 (6a). Four copper circuit plates 16 are formed from the Cu plate 16b, and four copper heat radiating plates 16'are formed from the Cu plate 16b'as shown in FIG. 6 (6b). Since the pattern is formed according to the portion covered with the resist pattern, the position of the copper circuit board 16 and the position of the copper heat dissipation plate 16'are accurately aligned so as to face each other across the silicon nitride ceramic assembly substrate. Can be matched. After this, the copper circuit plate 16 and the copper heat dissipation plate 16'may be subjected to Ni plating, Ag plating, Au plating, or the like.

After that, by dividing the silicon nitride ceramics assembly substrate 12a along the second break lines 18 and 18', the circuit forming portion (corresponding to the circuit board 20) and the edge portion 17 (corresponding to the second ear portion) are formed. Separated to obtain each circuit board 20. As shown in FIG. 7, the circuit board 20 includes a copper circuit board 16, a copper heat radiating plate (not shown), and a ceramic substrate portion 19. The position of the copper circuit board 16 on the front surface and the back surface in the surface of the ceramic substrate portion 19 when viewed from the direction perpendicular to the surface of the ceramic substrate portion 19 (the surface provided with the circuit board or the heat radiation plate). The position of the copper heat dissipation plate in.

(Embodiment 2)
A method for manufacturing another silicon nitride ceramics sintered substrate and a method for manufacturing a circuit board according to the present invention will be described with reference to FIGS. 1, 2, and 8 to 13. First, a silicon nitride ceramics sintered substrate similar to that shown in FIG. 1 is produced, and a silicon nitride ceramics assembly substrate 12a similar to that shown in FIG. 2 is obtained from the substrate. Then, the brazing material 16c is arranged as shown in FIG. 8 by applying the brazing material paste to the front surface of the substrate of FIG. 2 by screen printing. Further, by inverting the front and back surfaces of the substrate and applying the brazing material paste to the back surface of the substrate by screen printing, the brazing material is arranged in the same manner as the brazing material 16c.

Then, as shown in FIG. 9, the original Cu plate 16d is provided on the front surface (surface) of the substrate of FIG. 8 so as to cover the main part of the brazing material 16c. At this time, the Cu plate 16d is prevented from covering the through hole 5. Further, the front and back surfaces of the substrate are inverted, and another original Cu plate is provided so as to cover the main part of the brazing material on the back surface. At this time, the Cu plate of the original plate is prevented from covering the through hole 5. Then, the brazing material and the brazing material 16c are formed into a brazing material layer by heat-treating the laminated body in which the Cu plate / brazing material / silicon nitride ceramics assembly substrate (12a) / brazing material 16c / Cu plate 16d are laminated in this order. And braze.

Then, using an image analysis device or the like, the centers of the respective positioning through holes 5 are calculated on the front surface, and from the four centers related to the positioning through holes 5, the silicon nitride ceramic assembly substrate (12a) Calculate the first center point of. Based on the first coordinates of the silicon nitride ceramics assembly substrate obtained by the "four centers" and the "first center point", a method of forming a photoresist or a method of applying a resist film is used to form a Cu plate 16d. Four resist patterns are formed on the surface. The outline and position of the resist pattern can be determined by the above-mentioned first coordinates.

Further, the front and back surfaces of the substrate are inverted, the centers are calculated by the respective positioning through holes 5 on the back surface, and the silicon nitride ceramics assembly substrate (12a) is formed from the four centers related to the positioning through holes 5. Calculate the second center point of. Based on the second coordinates of the silicon nitride ceramics assembly substrate obtained by the "four centers" and the "second center point", the Cu plate 16d is used by a method of forming a photoresist or a method of pasting a resist film. Four resist patterns are formed on the Cu plate on the opposite side. The outline and position of the resist pattern can be determined by the second coordinates. By using the same four through holes 5 on the front surface and the back surface (using them as a common positioning reference), the first and second coordinates can be shared, or the first center point can be used. And the second center point can be matched, and the positions of the resist patterns facing each other across the silicon nitride ceramic assembly substrate can be accurately aligned so as to overlap when viewed through.

Then, by patterning the Cu plate 16d and another Cu plate by an etching process, as shown in FIG. 10, four copper circuit plates 16 are formed from the Cu plate 16d on the front surface, and on the back surface. Four copper heat dissipation plates are formed from another Cu plate. Since the pattern is formed according to the portion covered with the resist pattern, the position of the copper circuit board 16 and the position of the copper heat dissipation plate are accurately aligned so as to face each other with the silicon nitride ceramic assembly substrate sandwiched between them. .. After this, the copper circuit plate 16 and the copper heat dissipation plate may be subjected to Ni plating, Ag plating, Au plating, or the like.

Next, in the configuration of FIG. 10, the brazing material layer 16c'derived from the brazing material 16c has a portion not covered by the copper circuit plate 16 on the front surface, and the brazing material layer derived from the brazing material on the back surface. There are parts that are not covered by the copper radiator plate, and these are exposed brazing material layers. When these exposed brazing material layers are removed by selective etching, as shown in FIG. 11, a configuration having a copper circuit plate 16 and a copper heat radiating plate so as to face each other with the silicon nitride ceramic assembly substrate interposed therebetween. To get. After this, the copper circuit plate 16 and the copper heat dissipation plate may be subjected to Ni plating, Ag plating, Au plating, or the like.

Then, as shown in FIG. 12, second break lines 18 and 18'by the second scribe holes are formed on the surface of the silicon nitride ceramic assembly substrate. The second break line 18 is formed along the side break line 13, and the distance between the side break line 13 and the second break line 18 is larger than the distance L1. The through hole 5 is located at a position corresponding to the second ear portion. For example, the two second break lines 18'are formed so as to intersect the midpoints of, for example, the four second break lines 18.

After that, the circuit forming portion (corresponding to the circuit board 20) and the edge portion 17 (corresponding to the second ear portion) are separated by dividing the silicon nitride ceramics assembly substrate along the second break lines 18 and 18'. Then, each circuit board 20 is obtained. The circuit board 20 has the same configuration as that of FIG. 7, and has a copper circuit board 16, a copper heat radiating plate (not shown), and a ceramic substrate portion 19. When viewed from the direction perpendicular to the surface of the ceramic substrate portion 19 (the surface provided with the circuit plate or the heat radiation plate), the position of the copper circuit plate 16 on the front surface in the surface of the ceramic substrate portion 19 and ( It matches the position of the copper heat dissipation plate on the back surface (as seen through).

(Through hole for positioning)
A through hole for positioning will be described with reference to FIG. FIG. 13A is a cross-sectional view of the through hole 5 in FIG. 1 and the like, and the diameter of the through hole is emphasized. When the through hole is formed, the side where the front surface of the silicon nitride ceramics assembly substrate 12 is irradiated with the laser is the “incident side” in the drawing, and the side through which the laser penetrates is the “penetration side” in the drawing. Although it depends on the laser irradiation conditions, the diameter of the through hole increases slightly from the penetrating side toward the incident side, and the diameter increases around the edge of the incident side, resulting in a curved inclination in cross-sectional view. is there. FIG. 13B is a cross-sectional view showing an example of another through hole 5', and the inner wall of the through hole is positively inclined and penetrates in the cross-sectional view of the silicon nitride ceramics assembly substrate (12). The diameter of the hole increases from the penetrating side to the incident side, and such a through hole 5'can also be used.

For these positioning through holes, the center of the opening on the incident side (virtual center) can be calculated by using an image analyzer or the like when viewed from the direction perpendicular to the substrate, or the center of the opening on the through side (virtual center). Center) is calculated. Vertical virtual lines that pass through the center and intersect with the surface of the silicon nitride ceramic assembly substrate are shown by alternate long and short dash lines in FIGS. 13 (a) and 13 (b), respectively.

The shape of the through hole opening is preferably circular when viewed from the direction perpendicular to the substrate. This is because even if the size of the circle is different between the front side and the back side, the position of the center of the circle is the same. As a method of finding the center of the circular opening, for example, at least three virtual lines are drawn for the circular shape, and the intersection of the circular edge and the virtual line is specified from the shading of the image of the circular edge. Then, a method of obtaining a circular center (that is, the center of the opening of the through hole) from at least three intersections can also be used. The shape of the opening of the through hole may also be elliptical, rectangular, or cross-shaped, but the more the shape of the opening is deformed from the circular shape, the higher the accuracy of the center of the opening. If you try to calculate it, an error may easily occur. That is, there is a case where the center of the shape of the opening (calculated manually by the inventor from the image) and the center of the opening calculated by the image analyzer are likely to be misaligned. On the other hand, the edge of the circular opening is highly accurate because the center of the circle is determined to be one point even if the outline appears to have a gradation due to the influence of the curved slope on the wall surface. The center of the opening is calculated with.

(Embodiment 3)
A method for manufacturing another silicon nitride ceramics sintered substrate and a method for manufacturing a circuit board according to the present invention will be described with reference to FIGS. 14 and 15. First, the silicon nitride ceramics sintered substrate of FIG. 14 is produced, which is common to the silicon nitride ceramics sintered substrate of FIG. 1 except that the through holes 5 are limited to two. The positions of the through holes 5 on the upper right side and the positions of the through holes 5 on the lower left side of the silicon nitride ceramics assembly substrate are the same as those in FIG. However, through holes are not formed in the lower right and upper left of the silicon nitride ceramics assembly substrate (x marks are shown for convenience in places where there are no through holes).

On the front surface, the midpoint 100 (indicated by □ in FIG. 14) of the virtual line (dashed line) connecting the center of the through hole 5 on the upper right and the center of the through hole 5 on the lower left is the third. Calculated as the center point. For example, as shown in FIG. 15, the center point of the Cu plate 16b of the original plate is set to the midpoint 100. A method for forming a photoresist based on the third coordinates of the silicon nitride ceramics assembly substrate obtained by the "center of the through hole 5 in the upper right and the center of the through hole 5 in the lower left" and the "third center point". When using the method of pasting a resist film, the outline and position of the resist pattern are determined by the above-mentioned third coordinates.

Further, the substrate is inverted, and for the back surface, the midpoint of the virtual line connecting the centers of the two through holes 5 is calculated as the fourth center point. When using the method of forming a photoresist or the method of applying a resist film based on the fourth coordinates of the silicon nitride ceramics assembly substrate obtained by the "centers of the two through holes 5" and the "fourth center point", The outline and position of the resist pattern are determined by the fourth coordinate. Then, the requirements and steps other than the coordinates related to the through hole may be the same as those in the first or second embodiment, and the same circuit board as in FIG. 7 can be manufactured. Therefore, when viewed from the direction perpendicular to the surface of the ceramic substrate portion 19 (the surface provided with the circuit board or the heat radiating plate), the position of the copper circuit plate 16 on the front surface in the surface of the ceramic substrate portion 19 , It matches the position of the copper heat dissipation plate on the back surface (as seen through).

(Embodiment 4)
With respect to the configuration of FIG. 14, one through hole can be further added to one of the places marked with x in the lower right or upper left. For example, when adding a through hole 5 at the place of x in the lower right, "the center of the through hole 5 in the upper right, the center of the through hole added in the lower right, and the center of the through hole 5 in the lower left" and "the center of the through hole 5 obtained from them". When using the method of forming a photoresist or the method of applying a resist film based on the'third coordinates' of the silicon nitride ceramics assembly substrate obtained by the'third center point', the outline and position of the resist pattern are set as described above. Determined by the'third coordinate'.

Further, the substrate is inverted, and the back surface is a photoresist based on the "fourth coordinates of the silicon nitride ceramics assembly substrate" obtained by the "centers of the three through holes" and the "fourth center point'" obtained from them. The outline and position of the resist pattern are determined by the above-mentioned fourth coordinate'when the method of forming the resist pattern or the method of pasting the resist film is used. Then, the requirements and steps other than the coordinates related to the through holes may be the same as those of any of the first to third embodiments, and the same circuit board as in FIG. 7 can be manufactured. Therefore, when viewed from the direction perpendicular to the surface of the ceramic substrate portion 19 (the surface provided with the circuit board or the heat radiating plate), the position of the copper circuit plate 16 on the front surface in the surface of the ceramic substrate portion 19 , It matches the position of the copper heat dissipation plate on the back surface (as seen through).

(Embodiment 5)
A method for manufacturing another silicon nitride ceramics sintered substrate and a method for manufacturing a circuit board according to the present invention will be described with reference to FIGS. 16 and 17. First, the silicon nitride ceramics sintered substrate of FIG. 16 is produced. Of the four sides constituting the outer edge 10 of the silicon nitride ceramics sintered substrate, the shorter side is the short side. With respect to the side break line 13 formed along the short side, a through hole 5 for positioning is formed at a predetermined distance L1 on the inside (the side opposite to the outer edge 10). The through hole 5 is common to the silicon nitride ceramics sintered substrate of FIG. 1 except that the through hole 5 is provided not in the vicinity of the long side but in the vicinity of the short side. For example, as shown in FIG. 17, when a brazing material 16a or a Cu plate 16b of an original plate is provided and a method of forming a photoresist or a method of pasting a resist film is used, the outline and position of the resist pattern are set to the above-mentioned first. It is determined by the coordinates or the same coordinates as the second coordinate. Therefore, a circuit board similar to that shown in FIG. 7 can be manufactured. When viewed from the direction perpendicular to the surface of the ceramic substrate portion 19 (the surface provided with the circuit plate or the heat radiation plate), the position of the copper circuit plate 16 on the front surface in the surface of the ceramic substrate portion 19 and ( It matches the position of the copper heat dissipation plate on the back surface (as seen through).

In the silicon nitride ceramics sintered substrate according to the present invention, for example, as shown in FIG. 1, the corner portions are chamfered in a direction inclined from the side break lines 13 at the corner portions where the side break lines 13 intersect with each other. The corner break line 14 is formed. The square break line 14 may be a slit penetrating the substrate, a slit 14 formed by connecting through holes for chamfering, or a plurality of through holes (through holes for chamfering). They may be arranged in series (provided that the pitch of the through holes is smaller than the pitch of the slit holes of the side break line). Due to the presence of the square break line, when the silicon nitride ceramics sintered substrate 1 is bent and divided into the silicon nitride ceramics assembly substrate 12 and the ear portion 11, cracks and chips are generated at the four corners of the silicon nitride ceramics assembly substrate. Can be suppressed.

In the silicon nitride ceramics sintered substrate according to the present invention, the diameter of the scribe holes 13a on the surface of the substrate is preferably 300 μm or less, and the depth is preferably 1/3 or more of the thickness of the silicon nitride ceramics assembly substrate, for example. The diameter of the scribe hole largely depends on the beam spot diameter of the laser used, but is more preferably 30 to 200 μm, still more preferably 50 to 150 μm. The depth of the scribe holes is more preferably 80 to 300 μm, 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 twice or less the diameter of the scribe holes, more preferably equal to the diameter of the scribe holes, and particularly preferably determined by the splittability when the substrate is divided. This pitch control can be adjusted by machining speed control, and may be linked with the number of laser output pulses or the like.

In the silicon nitride ceramics sintered substrate according to the present invention, the slit 14 formed at the corner where the side break lines due to the scribing holes intersect and is formed by connecting the through holes for chamfering is, for example, a slit having a slit width of 30 to 200 μm. The length of the above is preferably 2.8 to 8.4 mm. The diameter or slit width of the through hole for chamfering is more preferably 20 to 150 μm, further preferably 30 to 100 μm. The length of the slit is more preferably 3.0 to 8.0 mm, further preferably 3.5 to 7.5 mm. Further, the width and length of the break line due to the through hole for chamfering can be made the same as the slit dimension.

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

In the method for manufacturing a silicon nitride ceramics sintered substrate according to the present invention, it is preferable that the through hole for positioning, the scribe hole, the through hole for chamfering, or the slit is formed by a laser. For example, a YAG laser or a carbon dioxide laser (CO ₂ laser) is used. Processing by irradiation with a YAG laser or a carbon dioxide laser is suitable for forming through holes penetrating the substrate or intermittently forming deep holes.

In the method for manufacturing a silicon nitride ceramics sintered substrate according to the present invention, it is preferable to repeat irradiation of the laser beam spot a plurality of times when forming a through hole for positioning. When the irradiation is repeated a plurality of times to dig down the hole, the energy density for each irradiation can be lowered, so that cracks due to thermal shock are less likely to be formed on the surface (inner wall) of the through hole.

The thickness of the silicon nitride ceramics sintered substrate and the silicon nitride ceramics assembly substrate according to the present invention is, for example, 0.2 mm to 1.0 mm. More specifically, the thickness is preferably set to, for example, 0.25 mm to 0.65 mm. In the silicon nitride ceramics sintered substrate and the silicon nitride ceramics assembly substrate according to the present invention, the fracture toughness value is set to, for example, 5.0 MPa · m ^1/2 or more. More specifically, it is preferable that the fracture toughness value is, for example, 5.0 to 7.5 MPa · m ^1/2 . Regarding the method for manufacturing a circuit board of the present invention, at least one of a Cu plate and an Al plate can be used as the metal plate. Further, the method of joining the silicon nitride ceramic assembly substrate and the metal plate is not limited to brazing, and a direct joining method or the like may be used.

Hereinafter, the present invention will be specifically described based on examples. The present invention is not necessarily limited to the following examples.

(Example)
In the raw material for forming a silicon nitride ceramic, using a silicon nitride powder in the main raw material, with Y ₂ O ₃ of 2 mass% of MgO and 3 wt% sintering aid, nitrogen sheets molded body produced Sintering in an atmosphere at a maximum temperature of 1850 ° C. and a holding time of 5 hours produced a rectangular silicon nitride ceramics sintered substrate 1 having a thickness of 0.32 mm, a length of 150 mm and a width of 200 mm. A carbon dioxide laser was used to form a side break line 13 with scribe holes 13a along the outer edge 10 at a position inside the outer edge 10 of the silicon nitride ceramics sintered substrate 1 (scribe 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 surface of the substrate, and as shown in FIG. 1, side break lines 13 formed by the scribe holes 13a are formed along each of the four sides. The width of the ear portion 11 was set to 5 mm.

Subsequently, using a carbon dioxide gas laser (output 100 W), the beam spots of the laser are scanned once, and the side break lines 13 and 45 are formed at the intersecting corners (4 points) of the side break lines 13 by the slit holes 13a, respectively. By continuously forming through holes for chamfering from a position protruding by L2 in the direction of inclination, a slit 14 formed by connecting the through holes for chamfering was formed (slit forming step).
Laser beam spot diameter = 0.07 mm
Processing speed = 15 mm / s
Slit protrusion length L2 = 0.7mm
Overall length of slit = 4.2 mm
Slit width on the substrate surface = 0.10 mm

Subsequently, using a carbon dioxide gas laser, the diameter of the beam spot was set to 0.2 mm, and a through hole 5 for positioning was formed inside the side break line 13 at a position separated by L1 = 0.5 mm. Here, in the direction along the side break line 13, the positioning through hole 5 is formed at a position 5 mm away from the nearby slit 14. Since there are four side break lines 13, as shown in FIG. 1, there are a total of four through holes 5 for positioning.

Then, the silicon nitride ceramics sintered substrate 1 according to FIG. 1 was bent, divided by the side break line 13, and divided into the silicon nitride ceramics assembly substrate 12 shown in FIG. 2 and the selvage portion 11. Then, as shown in FIG. 3, the second break lines 18 and 18'are formed on the silicon nitride ceramic assembly substrate 12a to form the silicon nitride ceramics 12a.

Then, as shown in FIG. 4, a brazing material (16a, 16a') was applied to the front side and the back side of the silicon nitride ceramic assembly substrate 12a by a screen printing method, respectively. _{For the brazing material, 0.3 parts by mass of TiH 2} was added to an alloy powder consisting of 70% by mass of Ag, 3% by mass of In, and 27% by mass of Cu (100 parts by mass in total), and an organic solvent was added. , An organic binder was added and kneaded to form a paste. After the silicon nitride ceramic assembly substrate coated with the brazing material is dried, 0.3 mm copper plates, that is, Cu plates (16b, 16b') are contact-arranged on the front side and the back side so as to cover the brazing material, and the laminated body is formed. Obtained (see FIG. 5). Then, the mixture was heat-treated in vacuum at 800 ° C. for 20 minutes while pressurizing to prepare a bonded body of the silicon nitride ceramic assembly substrate and the Cu plate. A layer of brazing material having a thickness of about 30 μm is formed between the silicon nitride ceramic assembly substrate and the Cu plate.

Then, using an image analysis device, the center (circular center on the incident side) of each positioning through hole 5 is calculated on the front surface, and the four centers related to the obtained positioning through hole 5 are calculated. The first center point of the silicon nitride ceramics assembly substrate (12a) was calculated from the above. The first coordinates of the silicon nitride ceramic assembly substrate obtained by the "four centers" and the "first center point" were determined. Then, with respect to the bonded body, an etching resist ink curable with ultraviolet rays was applied onto the Cu plate on the front side, and then the etching resist ink was cured by irradiating with ultraviolet rays to form a pattern of the resist film. The positioning of the mask when exposing the pattern of the resist film was performed using the above-mentioned first coordinates. As the etching resist ink, an alkali peeling type ink was used.

Then, the substrate is inverted, the center (circular center on the through side) is calculated for each positioning through hole 5 on the back surface, and silicon nitride is obtained from the four centers related to the obtained positioning through hole 5. The second center point of the ceramic assembly substrate (12a) was calculated. The second coordinates of the silicon nitride ceramic assembly substrate obtained by the "four centers" and the "second center point" were determined. Then, after applying the etching resist ink on the Cu plate on the back side of the bonded body, the etching resist ink was cured by irradiating with ultraviolet rays to form a pattern of the resist film. The positioning of the mask when exposing the pattern of the resist film was performed using the above-mentioned second coordinates.

An unnecessary Cu plate (that is, a resist film) that is out of the pattern of the circuit plate or the heat radiating plate by etching with an etching solution of copper chloride 55 held at 30 ° C. (a mixed solution containing copper chloride, hydrochloric acid, and hydrogen peroxide). The Cu plate in the portion not covered with (Cu plate) was removed.

Then, in order to remove the portion where the brazing material protrudes from the Cu plate (the protruding portion of the brazing material), a first brazing material etching treatment (carboxylic acid and / or carboxylate, and an acidic solution containing hydrogen peroxide) is performed. Etching treatment (etching treatment with) and second brazing material etching treatment (etching treatment with a solution containing ammonium hydrogenfluoride and hydrogen peroxide) were performed in order to remove the protruding portion of the brazing material, and the bonded body shown in FIG. Got

Then, the conjugate was immersed in a 3% by mass aqueous sodium hydroxide solution to remove the resist film. Then, after undergoing chemical polishing and cleaning with ion-exchanged water, the front copper plate (circuit plate) and the back copper plate (heat dissipation plate) were Ni-plated. This chemical polishing was carried out using a sulfuric acid-based general commercial solution for gloss treatment.

In this way, an aggregate of circuit boards in which a plurality of sets of Ni-plated copper circuit boards 16 and copper heat dissipation plates were joined via a silicon nitride ceramics assembly substrate and a brazing material layer was obtained. Then, by dividing by the second break lines 18, 18', as shown in FIG. 7, the circuit board 20 having the copper circuit board 16 and the copper heat radiating plate (not shown) and the ceramic substrate portion 19 is formed. I got more than one.

Of the above steps, the case where the resist film pattern is formed will be described. In the pattern of the resist film, the position accuracy (corresponding to "deviation") of the center point in the long side direction falls within the range of ± 0.025 mm when the opening is circular in the through hole for positioning, and the opening is open. In the case of the cross shape, it was within the range of ± 0.04 mm. Therefore, it was possible to prevent the center of the metal plate on the front surface side and the center of the metal plate on the back surface side from being displaced from each other, and to improve the pass rate of the circuit board.

(Comparative Example 1)
Positioning was performed by bringing the long side of the silicon nitride ceramic assembly substrate into contact with the jig without forming the through hole for positioning (the same as in the embodiment except for the requirement for the through hole for positioning). However, although the burrs generated by the removal of the ears were removed, the pattern of the resist film was affected by the variation in the flatness of the long side (the side surface of the substrate along the long side) itself. The position accuracy (deviation) in the long side direction was within the range of ± 0.08 mm.

(Comparative Example 2)
Marks (marks by coating film or drawing) were formed on the front surface and the back surface of the silicon nitride ceramic assembly substrate without forming through holes for positioning, and used for positioning. However, the pattern of the resist film has inferior position accuracy in the long side direction as compared with the case of the example. This does not use a common standard between the process of marking the front surface and the process of marking the back surface, so that there is a deviation when going through the handling process for inverting the silicon nitride ceramic assembly substrate. It can be considered that it has occurred.

When the position accuracy in the short side direction was compared with respect to the above-mentioned Examples, Comparative Examples 1 and 2, the Examples were found to be within the range where the position accuracy was smaller than that of Comparative Examples 1 and 2.

1: Silicon nitride ceramics sintered substrate,
5,5': Through hole,
10: Outer edge,
11: Ear,
12, 12a: Silicon nitride ceramic assembly substrate,
13: Side break line, 13a: Scribe hole,
14: Slit, 15: Square break line,
16: Copper circuit board,
16': Copper radiator plate,
16a, 16a', 16c: wax material,
16c': Wax layer,
16b, 16b', 16d: Original Cu plate,
17: Edge,
18, 18': Second break line,
19: Ceramic substrate part, 20: Circuit board,
100: Center point

Claims (17)

For manufacturing a silicon nitride ceramics assembly substrate having a circuit forming portion and an edge for taking a large number of circuit boards from a rectangular silicon nitride ceramics sintered substrate having an ear portion around the silicon nitride ceramics assembly substrate. Silicon nitride ceramics sintered substrate
It is provided with a scribe hole for dividing the silicon nitride ceramic assembly substrate and the selvage portion, and a through hole for positioning.
The scribe holes form a side break line by the scribe holes along the outer edge at a position inside from the outer edge of the silicon nitride ceramics sintered substrate.
A silicon nitride ceramics sintered substrate, characterized in that the through hole for positioning is formed inside the side break line. It is a silicon nitride ceramics assembly substrate having a circuit forming portion and an edge portion for taking a large number of circuit boards, and is characterized in that a through hole for positioning is formed inside the side of the silicon nitride ceramics assembly substrate. Silicon nitride ceramics assembly substrate. For manufacturing a silicon nitride ceramics assembly substrate having a circuit forming portion and an edge for taking a large number of circuit boards from a rectangular silicon nitride ceramics sintered substrate having an ear portion around the silicon nitride ceramics assembly substrate. A method for manufacturing a silicon nitride ceramics sintered substrate.
A scribe hole forming step for dividing the silicon nitride ceramic assembly substrate and the selvage portion and a through hole forming step for positioning are provided.
In the scribe hole forming step, a side break line due to the scribe holes is formed along the outer edge at a position inside from the outer edge of the silicon nitride ceramics sintered substrate.
The positioning through hole forming step is a method for manufacturing a silicon nitride ceramics sintered substrate, characterized in that a through hole is formed inside the side break line. The silicon nitride ceramics sintered substrate according to claim 1, wherein at least two through holes are formed in the vicinity of the corners of the silicon nitride ceramics assembly substrate. The silicon nitride ceramics assembly substrate according to claim 2, wherein at least two through holes are formed in the vicinity of the corners of the silicon nitride ceramics assembly substrate. In the method for manufacturing a silicon nitride ceramics sintered substrate according to claim 3, the through hole is a common positioning reference for the front surface and the back surface of the silicon nitride ceramics sintered substrate. A method for manufacturing a silicon ceramics sintered substrate. In the silicon nitride ceramics sintered substrate according to claim 1, a center point obtained from at least two through holes formed in the vicinity of the corner of the silicon nitride ceramics assembly substrate and a center point of the silicon nitride ceramics assembly substrate. Is a silicon nitride ceramics sintered substrate characterized by matching. In the silicon nitride ceramics sintered substrate according to claim 1, the center point of the front surface obtained from at least two through holes formed in the vicinity of the corners of the silicon nitride ceramics assembly substrate, and the through holes. A silicon nitride ceramics sintered substrate characterized in that the center point on the back surface coincides with the center point. In the silicon nitride ceramic assembly substrate according to claim 2, the center point obtained from at least two through holes formed in the vicinity of the corner and the center point of the silicon nitride ceramic assembly substrate are the same. A characteristic silicon nitride ceramic assembly substrate. In the silicon nitride ceramics assembly substrate according to claim 2, the center point of the front surface obtained from at least two through holes formed in the vicinity of the corner and the center point of the back surface obtained from the through holes are one. A silicon nitride ceramics assembly substrate characterized by the fact that it is done. The silicon nitride ceramics sintered substrate according to claim 1, wherein the through holes have a circular opening shape. The silicon nitride ceramics assembly substrate according to claim 2, wherein the through hole has a circular opening shape. The silicon nitride ceramics sintered substrate according to claim 1, wherein the distance between the side break line and the through hole is 0.1 to 4.0 mm. The silicon nitride ceramics assembly substrate according to claim 2, wherein the distance between the side of the silicon nitride ceramics assembly substrate and the through hole is 0.1 to 4.0 mm. A method of manufacturing a circuit board by adding a step of providing a metal plate on the circuit side and a step of providing a metal plate on the heat dissipation side to the method for manufacturing a silicon nitride ceramics sintered substrate according to claim 3.
It is characterized in that one opening of the through hole is used when positioning the center point of the metal plate on the circuit side, and the other opening of the through hole is used when positioning the center point of the metal plate on the heat dissipation side. The method of manufacturing the circuit board. A step of manufacturing a silicon nitride ceramics assembly substrate having a circuit forming portion and an edge for taking a large number of circuit boards, and a step of forming a through hole for positioning inside the side of the silicon nitride ceramics assembly substrate. Have and
The silicon nitride ceramics assembly substrate includes a step of providing a metal plate on the circuit side and a step of providing a metal plate on the heat dissipation side.
It is characterized in that one opening of the through hole is used when positioning the center point of the metal plate on the circuit side, and the other opening of the through hole is used when positioning the center point of the metal plate on the heat dissipation side. The method of manufacturing the circuit board. In the method for manufacturing a circuit board according to claim 15 or 16.
When the first pattern of the resist is provided on the metal plate for the circuit side, the center point of the first pattern is determined by the center of one opening of the through hole.
A method for manufacturing a circuit board, characterized in that when a second pattern of a resist is provided on a metal plate for heat dissipation, the center point of the second pattern is determined by the center of the other opening of the through hole. ..

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