Ceramic substrate, joined body, and semiconductor device using the same

Abstract

To provide a ceramic substrate, a bonded body, and a semiconductor device using the same, with improved yield when forming a notch.SOLUTION: A ceramic substrate 1 having at least one notch 2 and an opening at the end of a notch includes a portion in which the angle of the notch between the notch and a straight line connecting the ends of the opening in the same notch at the angle of the end of the opening exceeds 90 degrees.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The embodiments described below generally relate to a ceramic substrate, a bonded body, and a semiconductor device using the same.

Background Art

[0002] As a substrate on which semiconductor elements are mounted, an insulating circuit substrate in which an insulating substrate and a circuit portion are bonded is used. As a method for fixing the insulating circuit substrate, screwing is used. As the screwing method, there are a method of providing a screwing portion on the substrate and a method of using a fixing jig. In recent years, in order to stabilize the screwing position and save space, a method of providing a screwing portion on the substrate has been tried. The screwing portion provided on the substrate is called a notch portion. When the opening end of the ceramic substrate is perpendicular as described in Patent Document 1 or 2, sufficient positional accuracy cannot be maintained at the screwing portion when screwing, and the screwing portion is likely to come off unless there are two or more notch portions or a combination of one notch portion and a through hole. On the other hand, when only a through hole is used as the screwing portion, a circuit portion for mounting a semiconductor element closer to the side portion of the substrate than the screwing portion (on the outer edge side) cannot be formed, so the area of the substrate cannot be effectively utilized. According to the present invention, it is possible to form a notch portion that enables accurate screwing and effectively utilizes the area of the substrate. When the opening end of the ceramic substrate is perpendicular as described in Patent Document 1 or 2, sufficient positional accuracy cannot be maintained at the screwing portion when screwing, and the screwing portion is likely to come off unless there are two or more notch portions or a combination of one notch portion and a through hole. On the other hand, when only a through hole is used as the screwing portion, a circuit portion for mounting a semiconductor element closer to the side portion of the substrate than the screwing portion (on the outer edge side) cannot be formed, so the area of the substrate cannot be effectively utilized. According to the present invention, it is possible to form a notch portion that enables accurate screwing and effectively utilizes the area of the substrate. It has been found that when only a through hole is used as the screwing portion, a circuit portion for mounting a semiconductor element closer to the side portion of the substrate than the screwing portion (on the outer edge side) cannot be formed, so the area of the substrate cannot be effectively utilized. According to the present invention, it is possible to form a notch portion that enables accurate screwing and effectively utilizes the area of the substrate. When only a through hole is used as the screwing portion, a circuit portion for mounting a semiconductor element closer to the side portion of the substrate than the screwing portion (on the outer edge side) cannot be formed, so the area of the substrate cannot be effectively utilized. According to the present invention, it is possible to form a notch portion that enables accurate screwing and effectively utilizes the area of the substrate. According to the present invention, it is possible to form a notch portion that enables accurate screwing and effectively utilizes the area of the substrate. The present invention is for solving such problems, and is a substrate having at least one notch portion, wherein an opening is provided at an end of the notch portion, and the angle of the notch portion formed by the ends of the openings and the notch portion exceeds 90 degrees at the angle of the ends of the openings. ​​​​​​The object of the present invention is to provide a ceramic substrate having a portion larger than the surface area of ​​the substrate. . Moreover, the above-mentioned control of the angle of the opening end may be performed microscopically. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2005-56933 A [Patent Document 2] International Publication No. 2011 / 004798 Summary of the Invention [Problem to be solved by the invention]

[0004] Because the edge of the opening was at a right angle, the board was easily removed when screwed in. The present invention is intended to address such a problem, and provides a method for manufacturing a cutout portion having an end portion The substrate has an opening at a portion thereof, and the opening ends are angled with each other at an angle between the opening ends. The angle of the cutout portion is larger than 90 degrees. The object of the present invention is to provide a ceramic substrate having the following characteristics. [Means for solving the problem]

[0005] The ceramic substrate according to the embodiment has at least one notch portion, The substrate has an opening at the end of the notch, and the opening is formed at an angle of the end of the opening. The angle between the mouth ends and the notch is greater than 90 degrees. The present invention is characterized in that the ceramic substrate has a [Brief description of the drawings]

[0006]

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Embodiments for Carrying Out the Invention

[0007] The ceramic substrate according to the present embodiment has at least one notch portion, and the substrate has an opening at an end of the notch portion, and a straight line connecting the ends of the openings and the notch portion has a portion where the angle of the notch portion is greater than 90 degrees. It is characterized by providing a ceramic substrate. The straight line connecting the ends of the openings and the notch form an angle θ1 of the notch. The angle θ1 is shown as the angle of the notch consisting of the straight line connecting the ends of the openings and the notch. It is shown in FIG. 1.

[0008] The ceramic substrate according to this embodiment may have, for example, one notch and one or more through holes, or may have two or more notches. Also, when providing a plurality of notches, the shapes of the notches may all be the same or different. Furthermore, the location where the notch is provided may be at the corner of the ceramic substrate. Also, when the ceramic substrate is rectangular, the location where it is provided may be on the short side or the long side. Also, the shape of the ceramic substrate may be substantially circular, substantially elliptical, or substantially semi-circular. Also, an R portion or a chamfered portion may be formed at one or more open ends. The fact that an R portion or a chamfered portion may be formed at the open end means that its size is not particularly examined. Therefore, it includes forming a minute chamfered portion or R portion only in the vicinity of the open end. Also, in the embodiment according to the present invention, when a perpendicular line is drawn from the midpoint between the open ends, there may be a portion where the shape of the notch is not symmetric with respect to this perpendicular line. Also, the notch formed in this way may be combined with a notch where the through hole or the opening is narrower than other portions, or a notch where the opening is at a right angle. When providing a plurality of notches, the shapes of the notches may all be the same or different. Furthermore, the location where the notch is provided may be at the corner of the ceramic substrate. Also, when the ceramic substrate is rectangular, the location where it is provided may be on the short side or the long side. Also, the shape of the ceramic substrate may be substantially circular, substantially elliptical, or substantially semi-circular. Also, an R portion or a chamfered portion may be formed at one or more open ends. The fact that an R portion or a chamfered portion may be formed at the open end means that its size is not particularly examined. Therefore, it includes forming a minute chamfered portion or R portion only in the vicinity of the open end. Also, in the embodiment according to the present invention, when a perpendicular line is drawn from the midpoint between the open ends, there may be a portion where the shape of the notch is not symmetric with respect to this perpendicular line. Also, the notch formed in this way may be combined with a notch where the through hole or the opening is narrower than other portions, or a notch where the opening is at a right angle. Also, the notch formed in this way may be combined with a notch where the through hole or the opening is narrower than other portions, or a notch where the opening is at a right angle. Also, the notch formed in this way may be combined with a notch where the through hole or the opening is narrower than other portions, or a notch where the opening is at a right angle. It may also be combined. FIG. 1 illustrates a combination of a notch and a through hole. Also, reference numeral 1 is the ceramic substrate, reference numeral 2 is the notch, and reference numeral 3 is the through hole. There is. P1 is the opening end 1. P2 is the opening end 2. θ1 is the angle of the notch part consisting of a straight line connecting the ends of the opening part and the notch part. FIG. 2 shows a structure in which the side that is not the opening part of the notch part is substantially trapezoidal, and the notch end shows the notch part shape when a substantially trapezoidal notch part is provided. Also, P3 indicates the end that is not an opening, and the symbol θ2 is the angle of the end on the side that is not the opening part. FIG. 4 shows an example in which a substantially semi-circular notch part is formed. P4 indicates the midpoint between the opening ends. Also, P5 is the farthest one among the intersections of the perpendicular line drawn from the midpoint between the opening ends and the substrate. Further, P6 is the intersection of the perpendicular line drawn from the midpoint between the opening ends and the notch part having the opening. Also, L1 is the distance between P4 and P5, and L2 is the distance between P4 and P6. FIG. 5 shows an example of a notch part having a shape that combines a substantially U shape and a substantially V shape. θ3 is the angle of the inner corner of the substrate at the end of the notch part, and θ4 is the angle of the boundary part between the R part or C part and the opening part. FIG. 6 shows an example where the two notch parts are not of the same shape. FIG. 7 shows an example in which a notch part is formed at the corner of the substrate. Also, it shows a case where another notch part has a shape close to a through hole. FIG. 8 shows an example of a structure having a chamfered part in an R shape at the opening end of the notch part. FIG. 9 shows an example of a structure having a chamfered part in a C shape at the opening end of the notch part. FIG. 10 shows an example of a bonded body in which a conductor part is provided and bonded to a ceramic substrate. 4 is the conductor part, 5 is the active metal bonding layer, and 6 is the bonded body. There is. P1 is the opening end 1. P2 is the opening end 2. θ1 is the angle of the notch part consisting of a straight line connecting the ends of the opening part and the notch part. FIG. 2 shows a structure in which the side that is not the opening part of the notch part is substantially trapezoidal, and the notch end shows the notch part shape when a substantially trapezoidal notch part is provided. Also, P3 indicates the end that is not an opening, and the symbol θ2 is the angle of the end on the side that is not the opening part. There is. P1 is the opening end 1. P2 is the opening end 2. θ1 is the angle of the notch part consisting of a straight line connecting the ends of the opening part and the notch part. FIG. 2 shows a structure in which the side that is not the opening part of the notch part is substantially trapezoidal, and the notch end shows the notch part shape when a substantially trapezoidal notch part is provided. Also, P3 indicates the end that is not an opening, and the symbol θ2 is the angle of the end on the side that is not the opening part. FIG. 10 shows an example of a bonded body in which a conductor part is provided and bonded to a ceramic substrate. 4 is the conductor part, 5 is the active metal bonding layer, and 6 is the bonded body. There is. P1 is the opening end 1. P2 is the opening end 2. θ1 is the angle of the notch part consisting of a straight line connecting the ends of the opening part and the notch part. FIG. 2 shows a structure in which the side that is not the opening part of the notch part is substantially trapezoidal, and the notch end shows the notch part shape when a substantially trapezoidal notch part is provided. Also, P3 indicates the end that is not an opening, and the symbol θ2 is the angle of the end on the side that is not the opening part. There is. P1 is the opening end 1. P2 is the opening end 2. θ1 is the angle of the notch part consisting of a straight line connecting the ends of the opening part and the notch part. FIG. 2 shows a structure in which the side that is not the opening part of the notch part is substantially trapezoidal, and the notch end shows the notch part shape when a substantially trapezoidal notch part is provided. Also, P3 indicates the end that is not an opening, and the symbol θ2 is the angle of the end on the side that is not the opening part. FIG. 6 shows an example where the two notch parts are not of the same shape. FIG. 7 shows an example in which a notch part is formed at the corner of the substrate. Also, it shows a case where another notch part has a shape close to a through hole. FIG. 8 shows an example of a structure having a chamfered part in an R shape at the opening end of the notch part. FIG. 9 shows an example of a structure having a chamfered part in a C shape at the opening end of the notch part. There is. P1 is the opening end 1. P2 is the opening end 2. θ1 is the angle of the notch part consisting of a straight line connecting the ends of the opening part and the notch part. FIG. 2 shows a structure in which the side that is not the opening part of the notch part is substantially trapezoidal, and the notch end shows the notch part shape when a substantially trapezoidal notch part is provided. Also, P3 indicates the end that is not an opening, and the symbol θ2 is the angle of the end on the side that is not the opening part. There is. P1 is the opening end 1. P2 is the opening end 2. θ1 is the angle of the notch part consisting of a straight line connecting the ends of the opening part and the notch part. FIG. 2 shows a structure in which the side that is not the opening part of the notch part is substantially trapezoidal, and the notch end shows the notch part shape when a substantially trapezoidal notch part is provided. Also, P3 indicates the end that is not an opening, and the symbol θ2 is the angle of the end on the side that is not the opening part. There is. P1 is the opening end 1. P2 is the opening end 2. θ1 is the angle of the notch part consisting of a straight line connecting the ends of the opening part and the notch part. FIG. 2 shows a structure in which the side that is not the opening part of the notch part is substantially trapezoidal, and the notch end shows the notch part shape when a substantially trapezoidal notch part is provided. Also, P3 indicates the end that is not an opening, and the symbol θ2 is the angle of the end on the side that is not the opening part. There is. P1 is the opening end 1. P2 is the opening end 2. θ1 is the angle of the notch part consisting of a straight line connecting the ends of the opening part and the notch part. FIG. 2 shows a structure in which the side that is not the opening part of the notch part is substantially trapezoidal, and the notch end shows the notch part shape when a substantially trapezoidal notch part is provided. Also, P3 indicates the end that is not an opening, and the symbol θ2 is the angle of the end on the side that is not the opening part. There is. P1 is the opening end 1. P2 is the opening end 2. θ1 is the angle of the notch part consisting of a straight line connecting the ends of the opening part and the notch part. FIG. 2 shows a structure in which the side that is not the opening part of the notch part is substantially trapezoidal, and the notch end shows the notch part shape when a substantially trapezoidal notch part is provided. Also, P3 indicates the end that is not an opening, and the symbol θ2 is the angle of the end on the side that is not the opening part. FIG. 11 shows a semiconductor device in which a semiconductor element is mounted on the joined body shown in FIG. 10. 7 is a semiconductor element, 8 is a bonding layer (between the semiconductor element and the conductor portion), 9 is a plating film and 10 is a semiconductor device. FIG. 12 shows an example of the side shape of the notch portion of the ceramic substrate.

[0009] At the angle of the end of the opening, the ends of the openings in the same notch portion and the notch portion or the like. The portion having a notch angle exceeding 90 degrees is preferably at both ends on the opening side of each notch portion. It is more preferable that it is the both ends on the opening side of each notch portion. A more preferable range of the angle θ1 is 100 degrees or more and 170 degrees or less, and more preferably 100 degrees or more and 160 degrees or less. If the angle is less than 100 degrees, there is a possibility that the effect of making the angle of the opening exceed 90 degrees cannot be sufficiently obtained. On the other hand, if the angle is greater than 170 degrees, as described above, the end of the notch shape is too sharp, and there is a risk that the opening end will break when an impact is applied after screwing. When there are a plurality of notch portions, at least one angle θ1 may exceed 90 degrees. Also, it is more preferable that all the angles θ1 exceed 90 degrees. Further, an R portion or a chamfered portion may be formed on the substrate center side of the opening end. When an R portion or a chamfered portion is formed on the substrate center side of the opening end as described above, the angle on the notch portion side between the boundary portion (inflection point) between the R portion or the chamfered portion and the other portion and the straight line formed by the opening ends is defined as θ1. When there is no inflection point, the point closest to the center of the notch portion is used instead of the inflection point. Also, the size of the R portion or the C portion is not particularly limited. When there are a plurality of notch portions, at least one angle θ1 may exceed 90 degrees. It is more preferable that all the angles θ1 exceed 90 degrees. Further, an R portion or a chamfered portion may be formed on the substrate center side of the opening end. When an R portion or a chamfered portion is formed on the substrate center side of the opening end as described above, the angle on the notch portion side between the boundary portion (inflection point) between the R portion or the chamfered portion and the other portion and the straight line formed by the opening ends is defined as θ1. When there is no inflection point, the point closest to the center of the notch portion is used instead of the inflection point. Also, the size of the R portion or the C portion is not particularly limited. When an R portion or a chamfered portion is formed on the substrate center side of the opening end as described above, the angle on the notch portion side between the boundary portion (inflection point) between the R portion or the chamfered portion and the other portion and the straight line formed by the opening ends is defined as θ1. When there is no inflection point, the point closest to the center of the notch portion is used instead of the inflection point. Also, the size of the R portion or the C portion is not particularly limited. When an R portion or a chamfered portion is formed on the substrate center side of the opening end as described above, the angle on the notch portion side between the boundary portion (inflection point) between the R portion or the chamfered portion and the other portion and the straight line formed by the opening ends is defined as θ1. When there is no inflection point, the point closest to the center of the notch portion is used instead of the inflection point. Also, the size of the R portion or the C portion is not particularly limited. When an R portion or a chamfered portion is formed on the substrate center side of the opening end as described above, the angle on the notch portion side between the boundary portion (inflection point) between the R portion or the chamfered portion and the other portion and the straight line formed by the opening ends is defined as θ1. When there is no inflection point, the point closest to the center of the notch portion is used instead of the inflection point. Also, the size of the R portion or the C portion is not particularly limited. When an R portion or a chamfered portion is formed on the substrate center side of the opening end as described above, the angle on the notch portion side between the boundary portion (inflection point) between the R portion or the chamfered portion and the other portion and the straight line formed by the opening ends is defined as θ1. When there is no inflection point, the point closest to the center of the notch portion is used instead of the inflection point. Also, the size of the R portion or the C portion is not particularly limited. Rather, it may be provided only near the opening end portion.

[0010] It is preferable that the end portion not on the opening side is substantially U-shaped, substantially trapezoidal, or substantially V-shaped. Further, when the end portion not on the opening side is substantially V-shaped, the angle is preferably 70 degrees or more as the angle on the notch side. If it is less than 70 degrees, there is a risk of cracks occurring from this end portion. As described above, if the angle of the end portion not on the opening side is 70 degrees or more than the angle on the notch side, it may be substantially V-shaped. The angle of the end portion not on the opening side is referred to as angle θ2. Angle θ2 is the angle formed by the side surfaces of the notch portion 2. It is shown as angle θ2 in FIG. 3. The substantially U-shaped means having an R portion at the end, and the substantially trapezoidal means having a C portion at the end. That is, the notch portion may be in a shape such as substantially pentagonal or substantially hexagonal.

[0011] Also, by having a chamfered portion at a location not on the opening side, the effect of suppressing the occurrence of cracks at this end portion can be further enhanced. This chamfered portion having an R portion or a C portion can further enhance the effect of suppressing the occurrence of cracks at this end portion. Therefore, it is more preferable to have an R portion or a C portion at a location not on the opening side. This shape is preferably substantially V-shaped (substantially V-shaped angle is 70 degrees or more), substantially trapezoidal, or substantially U-shaped. At this time, the substantially V-shaped (substantially V-shaped angle is 70 degrees or more), substantially trapezoidal, or substantially U-shaped can be of any size. Therefore, it may be very small provided at a very small part of the notch portion shape, or it may be formed over the entire notch portion. When the R part or the C part has a substantially U-shaped form, the effect of suppressing the generation of cracks can be further enhanced. Therefore, it is more preferable that the R part or the C part has a substantially U-shaped form. Here, the R part refers to a part formed by rounding off the corner of the tip of the notch part 2 to form a substantially U-shaped form. The C part refers to a part formed by linearly cutting off the corner of the tip of the notch part 2 to form a substantially trapezoidal shape. When the C part is provided in this way, it is more preferable that the angle of the notch part side formed by the upper base of this trapezoid is 30 degrees or more. At this time, it is more preferable that the ratio of the upper base to the lower base of the substantially trapezoid is such that the upper base / lower base is 0.1 or more. The upper base of the substantially trapezoid is the length of the side of the tip of the notch part 2. Also, the lower base of the substantially trapezoid is the length of the opening of the notch part 2. Therefore, it becomes the length of the straight line connecting the ends of the opening part. By doing so, it becomes possible to further reduce the cracks and chipping compared to the occurrence of cracks and chipping of the ceramic substrate during screwing when forming a substantially V-shaped form.

[0012] Even if the angle of the notch part (the angle marked as θ1 in FIG. 1 as an example) formed by the ends of the opening part and the notch part is less than 90 degrees, when an opening part is provided at the corner of a rectangular or square substrate, the opening end of the substrate of the opening part may become thin. In such a case it was sometimes difficult to maintain sufficient strength. Therefore, it is preferable that there is a portion where the inner angle of the substrate is 100 degrees or more at the angles of both ends of the opening part.

[0013] Also, it is preferable that the side surface shape is also controlled. In the side surface shape, at least one place ​​​​​​It is preferable that the above-mentioned end portion has an R portion or a C portion. It is more preferable that both ends of the surface (surface) have an R portion or a C portion. The openings may be on both the front and back surfaces. The arithmetic mean roughness Ra of the cross section is preferably 1.2 μm or less. The maximum height Rz of the cross section is preferably 2.0 μm or less. It is described in JIS B 0601:2013. JIS B 0601:2013 is an ISO Compatible with 4287:1997 / AMENDMENT 1:2009(IDT).

[0014] The midpoint between the ends of the cutout is P4, and when a perpendicular line is drawn from P4, Among the ends of the board on the perpendicular line, the end of the board farthest from P4 is P5, and the length of the board is P4 The distance between P5 and the perpendicular line is defined as P6. When the distance between P6 and P4 is 0.1, the length of the notch (L2) is determined as L2 / L1. The edge of the substrate part farthest from P4 is the cutout part. In the combination of and through hole, when the through hole is on the perpendicular line drawn from P4, the through hole is This indicates that the ignored end of the board portion is designated as P5. In addition, between the opening end (referred to as opening end 1) and another opening end (referred to as opening end 21), If the perpendicular line drawn from the point does not intersect with other cutouts, the length of the intersection of this perpendicular line with the board is The length is L1. If the perpendicular line drawn from the midpoint between the open ends intersects with another cutout, The distance between the line connecting the open ends of the other cutouts and the midpoint between the open ends is L1. In addition, the shortest point at which a perpendicular line drawn from a straight line connecting the opening ends intersects with the edge of the cutout portion is Let the longer one be L2. At this time, it is preferable that L2 / L1 is 0.1 or more and 0.4 or less. More preferably, it is 0.1 or more and 0.35 or less. If this value is greater than 0.4, there is a risk that the substrate may be easily cracked. On the other hand, if it is less than 0.05, there is a risk that the effect of providing the notch cannot be fully obtained. That is, when the notch is not at the corner and there is only one location where the notch exists, L1 corresponds to the length of the substrate. Let the maximum width of the notch be L3 and, when L3 is the opening width L4, it is preferable that 0.5 ≦ L4 / L3 < 1 in the ratio with L4. At this time, L3 is defined as the width parallel to L4. If L4 / L3 is less than 0.5, there is a risk that the opening end may be easily damaged. On the other hand, if it is 1 or more, the effect of making the angle of the opening greater than 90 degrees cannot be fully obtained, and there is a risk that the positional accuracy of the screw portion deteriorates.

[0015] Also, the ceramic substrate preferably contains one or two selected from silicon nitride, aluminum nitride, sialon, alumina, and zirconia as the main component. The main component refers to a component contained in an amount of 50% by mass or more. Further, the ceramic substrate is more preferably any one of a silicon nitride substrate, an aluminum nitride substrate, and an aldyl substrate. Aldyl is a material containing a total of 50% by mass or more of two kinds of alumina and zirconia.

[0016] The thickness of the ceramic substrate is preferably 0.1 mm or more and 1 mm or less. If the substrate thickness is less than 0.1 mm, there is a possibility of causing a decrease in strength. If the substrate thickness is greater than 1 mm, the insulating substrate itself becomes a heat resistor, and there is a possibility of reducing the heat dissipation of the ceramic circuit board. The three-point bending strength of the silicon nitride substrate is preferably 600 MPa or more. Silicon nitride The thermal conductivity of the substrate is preferably 80 W / m·K or more. By increasing the strength of the silicon nitride substrate, the substrate thickness can be reduced. Therefore, the three-point bending strength of the silicon nitride substrate is preferably 600 MPa or more, more preferably 700 MPa or more. The thickness of the silicon nitride substrate can be reduced to 0.40 mm or less, more preferably 0.30 mm or less. Also, the three-point bending strength of the aluminum nitride substrate is about 300 - 450 MPa. On the other hand, the thermal conductivity of the aluminum nitride substrate is 160 W / m·K or more. Since the strength of the aluminum nitride substrate is low, the substrate thickness is preferably 0.60 mm or more. The three-point bending strength of the aluminum oxide substrate is about 300 - 450 MPa, but the aluminum oxide substrate is inexpensive among ceramic substrates. The three-point bending strength of the aluminum zirconium substrate is as high as about 550 MPa, but its thermal conductivity is about 30 - 50 W / m·K. The aluminum zirconium substrate is a substrate made of a sintered body obtained by mixing aluminum oxide and zirconium oxide. The ceramic substrate is preferably a nitrogen-containing ceramic substrate. Among nitrogen-containing ceramic substrates, it is more preferably a nitride-based ceramic, more preferably either a silicon nitride substrate or an aluminum nitride substrate.

[0017] The thickness of the ceramic substrate is preferably 0.1 mm or more and 1 mm or less. If the substrate thickness is less than 0.1 mm, the strength may be insufficient. Also, if the substrate thickness is greater than 1 mm, the insulating substrate itself becomes a heat resistor, which may reduce the heat dissipation performance of the insulating circuit board.

[0018] In addition, the notch portion of the ceramic substrate described in the present application can be suitably used for screwing. It can be used.

[0019] Regarding the silicon nitride substrate, the three-point bending strength is preferably 600 MPa or more. The heat conductivity is preferably 80 W / m·K or more. By increasing the strength of the silicon nitride substrate, the substrate thickness can be reduced. Therefore, the three-point bending strength of the silicon nitride substrate is preferably 600 MPa or more, more preferably 700 MPa or more. The substrate thickness of the silicon nitride substrate can be reduced to 0.40 mm or less, and further to 0.30 mm or less. The three-point bending strength of the aluminum nitride substrate is about 300 to 450 MPa. On the other hand, the thermal conductivity of the aluminum nitride substrate is 160 W / m·K or more. Since the strength of the aluminum nitride substrate is low, the substrate thickness is preferably 0.60 mm or more. The three-point bending strength of the aluminum oxide substrate is about 300 to 450 MPa, but the aluminum oxide substrate is inexpensive. The three-point bending strength of the Aldyl substrate is as high as about 550 MPa, but the thermal conductivity is about 30 to 50 W / m·K. The Aldyl substrate is a substrate made of a sintered body obtained by mixing aluminum oxide and zirconium oxide. A conductor portion may be joined to the ceramic substrate having such a notch portion, or a notch portion having the above shape may be formed in the joined body with the ceramic substrate after joining the conductor portion. Also, the conductor portion may be provided only on one side of the ceramic substrate (referred to as a front conductor portion), or may be provided on the back surface (referred to as a back conductor portion), or may be provided on both sides. Further, the conductor portion may use those having different compositions for the back conductor portion and the front conductor portion. When the front conductor portion and the back conductor portion have the same composition, Since it is possible to provide a joined body that is easy to use, the back conductor part and the front conductor part preferably have the same composition. More preferably, they are the same. The conductor part is preferably a copper member or an aluminum member. The copper member is a copper plate, a copper alloy plate, a member produced by imparting a circuit shape to a copper plate, or a member produced by imparting a circuit shape to a copper alloy plate, and is made of copper or a copper alloy. The aluminum member is an aluminum plate an aluminum alloy plate, a member produced by imparting a circuit shape to an aluminum plate, or a member produced by imparting a circuit shape to an aluminum alloy plate, and is made of aluminum or an aluminum alloy. Hereinafter, a member produced by imparting a circuit shape to a copper plate will be referred to as a copper circuit. A member produced by imparting a circuit shape to an aluminum plate will be referred to as an aluminum circuit. The conductor part may be a metallized layer or a conductive thin film other than a copper member or an aluminum member. The metallized layer is formed by firing a metal paste. The thickness of the conductor part is 0.3 mm or more, and may be 0.6 mm or more. By increasing the thickness of the conductor part, the heat dissipation of the joined body can be improved. The thickness of the front conductor part may be the same as or different from the thickness of the back conductor part. As the conductor part, a copper member is particularly preferable. The copper member is preferably made of oxygen-free copper. Oxygen-free copper has a copper purity of 99.96 mass% or more as shown in JIS-H-3100. Preferably, the ceramic substrate and the copper member are joined via a joining layer containing titanium. In the active metal bonding method, an active metal brazing filler metal containing Ti is used. The active metal brazing filler metal contains silver or copper as a main component and contains Ti. The ceramic substrate and the copper member are preferably joined via a joining layer containing titanium. In the active metal bonding method, an active metal brazing filler metal containing Ti is used. The active metal brazing filler metal contains silver or copper as a main component and contains Ti. The ceramic substrate and the copper member are preferably joined via a joining layer containing titanium. In the active metal bonding method, an active metal brazing filler metal containing Ti is used. The active metal brazing filler metal

[0020] is preferably joined via a joining layer containing titanium. In the active metal bonding method, an active metal brazing filler metal containing Ti is used. The active metal brazing filler metal contains silver or copper as a main component and contains Ti. The ceramic substrate and the copper member contains silver or copper as a main component and contains Ti. The ceramic substrate and the copper member It is preferably joined via a bonding layer containing carbon. By adding carbon to the active metal brazing filler metal, a bonding layer containing carbon can be formed. By adding carbon to the active metal brazing filler metal, the fluidity of the brazing filler metal can be improved. Thereby, the bonding strength can be improved. The active metal brazing filler metal preferably contains 0 mass% or more and 70 mass% or less of Ag (silver), 15 mass% or more and 85 mass% or less of Cu (copper), and 1 mass% or more and 15 mass% or less of Ti (titanium) or TiH₂ (titanium hydride). Further, instead of Ti,

[0021] Nb or Zr may be used, or Nb and Zr may be added to Ti. However, the active metal brazing filler metal preferably contains 1 mass% or more and 15 mass% or less of Ti (titanium) or TiH₂ (titanium hydride). When using both Ti and TiH₂, the total of them is in the range of 1 mass% or more and 15 mass% or less. When using both Ag and Cu, the content of Ag is preferably 20 mass% or more and 70 mass% or less, and the content of Cu is preferably 15 mass% or more and 65 mass% or less. The brazing filler metal may contain one or both of Sn (tin) and In (indium) in an amount of 1 mass% or more and 50 mass% or less as required. The content of Ti or TiH₂ is preferably 1 mass% or more and 15 mass% or less. Further, the brazing filler metal may contain C (carbon) in an amount of 0.1 mass% or more and 2 mass% or less as required. The ratio of the composition of the active metal brazing filler metal is calculated based on the total of the solid raw materials to be mixed being 100 mass%. It is preferable that this solid raw material is in powder form. For example, with 3 types of Ag, Cu, and Ti as the active metal ... ... ... ... ... ...

[0022] ... ... When forming the brazing material, Ag + Cu + Ti = 100% by mass. Ag, Cu, TiH 2, When forming the active metal brazing material with the four kinds of In, Ag + Cu + TiH2 + In = 100 % by mass. When forming the active metal brazing material with the five kinds of Ag, Cu, Ti, Sn, and C, Ag + Cu + Ti + Sn + C = 100% by mass. It is preferable to mix a solvent corresponding to the composition with the powder raw material having the above composition. By mixing the solvent, the brazing material can be made into a paste form.

[0023] For the bonded body obtained by forming the conductor portion on the ceramic substrate in this way, the above-described notch shape may be provided. Further, a conductor portion may be provided on the ceramic substrate to which the above-described notch shape is imparted. Further, the conductor portion may be bonded with a previously provided circuit shape, or a circuit shape may be imparted after bonding the conductor portion to the ceramic substrate. It is also possible. It is also possible. It is such a thing.

[0024] The side surface of the copper member described above preferably has an inclined shape. That is, the side surface of the copper member is preferably inclined with respect to the in-plane direction and the thickness direction. The in-plane direction is a direction parallel to the bonding surface with the copper member of the ceramic substrate. The thickness direction is a direction connecting the ceramic substrate and the copper member, and is perpendicular to the in-plane direction. It is perpendicular to the in-plane direction. The thickness of the bonding layer 5 is preferably in the range of 10 μm or more and 60 μm or less. Further, the insulating circuit board preferably has a shape in which the bonding layer protrudes from the side surface of the copper member. A part of the protruding bonding layer is called a bonding layer protruding portion. The ratio (L / T) of the length L to the thickness T of the bonding layer protruding portion is preferably in the range of 0.5 or more and 3.0 or less. It is preferably in the range of 0.5 or more and 3.0 or less. The thickness of the protrusion part of the lamination layer is the thickness of the thickest part in the protrusion part of the bonding layer. The bonding layer The length of the protrusion part is the length of the longest part protruding from the side surface of the copper member. The bonding layer protrusion The thickness and length of the protrusion part are measured from an arbitrary cross-section of the ceramic copper circuit board. An inclined shape is provided on the copper member, and by providing the protrusion part of the bonding layer, the TCT characteristics of the ceramic copper circuit board can be improved. In addition, the bonding layer used for bonding the plating film and the semiconductor element or bonding the conductor part and the semiconductor element includes those using copper, those using tin, solder paste, and silver paste. Examples include those using copper, those using tin, solder paste, and silver paste. can be cited. The ceramic substrate is a silicon nitride substrate with a thickness of 0.4 mm or less, and the thickness of the copper member is preferably 0 .6 mm or more. When it is a thin silicon nitride substrate with a thickness of 0.4 mm or less, it has the effect of reducing the thermal resistance of the ceramic substrate. Also, when it is a thick copper plate with a thickness of 0.6 mm or more, the heat dissipation performance is improved. Furthermore, if it is a silicon nitride substrate with a three-point bending strength of 600 MPa or more, the effect can be easily obtained. Therefore, a combination of a silicon substrate with a thickness of 0.4 mm or less and a thick copper plate with a thickness of 0.6 mm or more may be used.

[0025] Next, the manufacturing method will be described.

[0026] As a method for forming the notch part, any method that can form the notch part described above may be used, such as a method of forming by laser, a method of applying pressure to provide a concave part when using a green sheet, a method of cutting with a wire saw, etc. Among these, the method of forming by laser is more preferable. This is because when this method is used, the notch part can be formed with high positional accuracy. Also, when using laser processing such as a method of forming by laser, a method of applying pressure to provide a concave part when using a green sheet, a method of cutting with a wire saw, etc. Among these, the method of forming by laser is more preferable. This is because when this method is used, the notch part can be formed with high positional accuracy. Also, when using laser processing it is because the notch part can be formed with high positional accuracy. Also, when using laser processing When the notch shape is viewed from the side of the substrate, the surface side can be open with respect to the center of the substrate. Also, the laser used is not particularly limited. However, it is preferably any one or more selected from a CO2 laser, a YAG laser (either fundamental wave, second harmonic, third harmonic, or fourth harmonic), a femtosecond laser, a picosecond laser, a semiconductor laser, an LD laser, an excimer laser, a YVO4 laser, and a DDL laser. Also, as a method of forming the notch by laser processing, it may be formed by a single laser irradiation, or it may be formed by irradiating multiple times. Further, if necessary, dust collection or assist gas may be used. Also, it may be irradiated from only one side, or it may be irradiated from both sides. However, when irradiating from both sides, the positional accuracy with respect to the first irradiation surface becomes important. Therefore, it is preferable to irradiate from only one side. To form the notch in this way, a continuous groove may be provided, or it may be in a dot shape. Also, the output mode of the laser may be pulsed, CW (continuous), or a combination of both. Also, it is preferable that the maximum depth of the groove formed by the laser with respect to the thickness of the substrate is controlled. Let the thickness of the substrate be t and the maximum depth of the groove be d. Then, it is preferably 0.5 < d / t ≦ 1. Here, the maximum depth of the groove means the total value when the laser is irradiated from both the front and back surfaces. Also, it is more preferably 0.7 ≦ d / t ≦ 1.0. Even more preferably, d / t is 1.0. Also, even more preferably, the formed groove exists across both the front and back surfaces, and the depth of the groove is always with respect to t. It is more preferably 1.0 in the ratio. In this way, by making the groove depth deeper than a certain level with respect to the substrate thickness and forming the groove, it is not necessary to apply excessive pressure in the separation step for separating the notch portion side from the substrate to form the notch portion, so the cost can be reduced. Also, the ceramic substrate may be honed as necessary. Honing can be performed before or after forming the notch shape, as long as it is a ceramic substrate after sintering. The timing of forming the notch portion is not particularly limited, but if it is formed at the time of the green sheet, there is a risk that the positional accuracy will decrease due to the subsequent sintering process. Therefore, it is preferably after sintering. Also, the notch portion may be formed either after or before joining the conductor portions. Also, by controlling the notch shape, the torque during screwing can be increased. Moreover, the ceramic substrate may be honed if necessary. Honing can be performed either before or after forming the notch shape, as long as it is a ceramic substrate after sintering. The timing of forming the notch portion is not particularly limited, but if it is formed at the time of the green sheet, there is a risk that the positional accuracy will decrease due to the subsequent sintering process. Therefore, it is preferably after sintering. Also, the notch portion may be formed either after or before joining the conductor portions. Moreover, the ceramic substrate may be honed if necessary. Honing can be performed either before or after forming the notch shape, as long as it is a ceramic substrate after sintering.

[0027] The timing of forming the notch portion is not particularly limited, but forming it at the time of the green sheet may cause a decrease in positional accuracy due to the subsequent sintering process. Therefore, it is preferably after sintering. Also, the notch portion may be formed either after or before joining the conductor portions. Moreover, the ceramic substrate may be honed if necessary. Honing can be performed either before or after forming the notch shape, as long as it is a ceramic substrate after sintering. The timing of forming the notch portion is not particularly limited, but forming it at the time of the green sheet may cause a decrease in positional accuracy due to the subsequent sintering process. Therefore, it is preferably after sintering. Also, the notch portion may be formed either after or before joining the conductor portions. Moreover, the ceramic substrate may be honed if necessary. Honing can be performed either before or after forming the notch shape, as long as it is a ceramic substrate after sintering. Also, by controlling the notch shape, the torque during screwing can be increased.

[0028] (Example) (Examples 1 - 7, Comparative Example 1) Table 1 shows the types and thicknesses of the ceramic substrates used. Also, for the silicon nitride substrate, those with a thermal conductivity of 90 W / m·K and a three-point bending strength of 700 MPa were used. For the aluminum nitride substrate, those with a thermal conductivity of 170 W / m·K and a three-point bending strength of 400 MPa were used. For the alumina (aluminum oxide) substrate, those with a thermal conductivity of 25 W / m·K and a strength of 450 MPa were used. For the zirconia (zirconium oxide) substrate, those with 25 W / m·K and a strength of 500 MPa were used. For the alzir substrate, those with a substrate of 25 W / m·K and a strength of 550 MPa were used. Moreover, the ceramic substrate may be honed if necessary. Honing can be performed either before or after forming the notch shape, as long as it is a ceramic substrate after sintering. The timing of forming the notch portion is not particularly limited, but forming it at the time of the green sheet may cause a decrease in positional accuracy due to the subsequent sintering process. Therefore, it is preferably after sintering. Also, the notch portion may be formed either after or before joining the conductor portions. Moreover, the ceramic substrate may be honed if necessary. Honing can be performed either before or after forming the notch shape, as long as it is a ceramic substrate after sintering. The timing of forming the notch portion is not particularly limited, but forming it at the time of the green sheet may cause a decrease in positional accuracy due to the subsequent sintering process. Therefore, it is preferably after sintering. Also, the notch portion may be formed either after or before joining the conductor portions. Moreover, the ceramic substrate may be honed if necessary. Honing can be performed either before or after forming the notch shape, as long as it is a ceramic substrate after sintering.

[0029]

Table 1

[0030] Table 2 shows the shapes of the cutout portions in the examples and comparative examples described in Table 1. Here, those described as 90 degrees or more in the column of the angle of the end of the cutout portion that is not the opening side indicate that the end was an R shape.

Table 2

[0031] For each example, 100 ceramic substrates with four cutout portions formed therein were prepared. After screwing in these ceramic substrates, the positional accuracy of the screwed portion was measured. Also, the exclusive area of the cutout portion is shown as a percentage (%) of the increase amount relative to Example 1. This ratio is based on the defective rate of the positional accuracy of the screwed portion and the exclusive area of the cutout portion. Taking one cutout portion with an increased area relative to Example 1 as 1, 400 locations (100 ceramic substrates × 4 cutout portions per ceramic substrate) were measured. This area increase rate is a comparison of the ratio occupied by the cutout portion shapes for fixing screws of the same size on substrates of the same size. This area increase rate is a comparison of the ratio occupied by the cutout portion shapes for fixing screws of the same size on substrates of the same size. occupied by the cutout portion shapes for fixing screws of the same size on substrates of the same size.

[0032]

Table 3

[0033] From Table 3, it can be seen that the ceramic substrates of the examples were able to reduce the generation of burrs, chips, and cracks during the formation of the cutout portions more than those with a right-angled end in the prior art.

[0034] Table 4 shows the measured values of the arithmetic surface roughness Ra and the maximum surface roughness Rz of the side surface of the notch. The side surface of the notch refers to the direction of the substrate thickness of the notch. Also, the shape of the notch refers to the shape when the notch is viewed from above. Also, the end of the opening refers to the shape on the side that is not the opening.

[0035]

Table 4

[0036] As can be seen from Table 2, Table 3, and Table 4, no notches or cracks occurred during screwing for those that satisfied all the claims. From this, controlling the shape of the notch of the substrate also sidewise contributes to increasing the yield during screwing.

Explanation of Signs

[0037] 1...Ceramic substrate 2...Notch 3...Through hole 4...Conductor part 5...Active metal bonding layer 6...Bonded body 7...Semiconductor element 8...Bonding layer (between the semiconductor element and the conductor part ) 9...Plating film 10...Semiconductor device θ1...Angle of the notch consisting of the ends of the opening and the notch θ2...Angle of the end that is not on the opening side θ3...Angle of the inner corner of the substrate at the end of the notch θ4...Angle of the boundary between the R part or C part and the opening P1...Opening end 1 P2...Opening end 2 P3...End that is not the opening P4...Midpoint between the opening ends P5…The point among the intersections of the perpendicular line drawn from the midpoint between the opening ends and the substrate that is the farthest P6…The intersection of the perpendicular line drawn from the midpoint between the opening ends and the notch having the opening

Claims

1. A substrate having at least one notch portion, wherein an end portion of the notch portion has an opening portion, and at a corner of the opening portion, a portion where an angle of the notch portion is greater than 90 degrees is provided, the notch portion being composed of a straight line connecting the ends of the opening portions in the same notch portion and the notch portion itself, A ceramic substrate having a maximum surface roughness Rz of 2.0 μm or less when the side surface of the notch portion is viewed.

2. The ceramic substrate according to claim 1, wherein a shape of an end portion other than the side of the opening portion is substantially U-shaped, substantially trapezoidal, or substantially V-shaped, and in the substantially V-shaped case, an angle of the end portion is 70 degrees or more as an angle on the notch portion side.

3. The ceramic substrate according to any one of claims 1 to 2, having an R portion or a C portion at a location other than the side of the opening portion.

4. The ceramic substrate according to any one of claims 2 to 3, wherein a shape of an end portion other than the side of the opening portion is substantially U-shaped.

5. The ceramic substrate according to any one of claims 1 to 4, having a portion where an inner angle of the substrate is 100 degrees or more at angles of both end portions of the opening portion.

6. The ceramic substrate according to any one of claims 1 to 5, wherein there is no boundary portion between a portion having an end portion other than the side of the opening portion and the opening portion, or an angle on the substrate side at the boundary portion is 100 degrees or more.

7. The ceramic substrate according to any one of claims 1 to 6, having an arithmetic surface roughness Ra of 1.2 μm or less when the side surface of the notch portion is viewed.

8. The ceramic substrate according to any one of claims 1 to 6, wherein a side surface shape of the notch portion has at least R portions or C portions at both end portions on the opening portion side.

9. In the notch portion, a midpoint between the ends of the notch portion is defined as P4. When a perpendicular line is drawn from P4, the end portion of the substrate on the perpendicular line that is farthest from P4 is defined as P5, and the length of the substrate is defined as the distance (L1) between P4 and P5. An intersection point of the perpendicular line and the notch portion having the opening portion is defined as P6. The length (L2) of the notch portion defined by the distance between P6 and P4 satisfies 0.1 ≤ L2 / L1 ≤ 0.

4. The ceramic substrate according to any one of claims 1 to 8.

10. The ceramic substrate according to any one or more of claims 1 to 9, wherein the ceramic is a nitrogen-containing ceramic.

11. A joined body, characterized in that a conductor portion is joined to the ceramic substrate according to any one or more of claims 1 to 10.

12. The joined body according to claim 11, wherein the conductor portion is a copper member or an aluminum member.

13. The joined body according to any one or more of claims 11 to 12, characterized in that a brazing material containing at least one of copper and silver and containing an active metal is used for joining the conductor portion and the ceramic substrate.

14. A semiconductor device, characterized in that a semiconductor element is mounted on the joined body according to any one or more of claims 11 to 13.

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