JP5039070B2 - Semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor apparatus in which a semiconductor device is securely bonded to the metal plate part of a ceramic circuit board, suppresses generation of thermal resistance failure and peeling or the like. <P>SOLUTION: The semiconductor apparatus includes a ceramic substrate, the metal plate mainly formed of aluminum and directly bonded on a surface of the ceramic substrate, and the semiconductor device bonded to the metal plate. A plurality of grooves are formed on a part, where the semiconductor device is bonded, of a main surface of the metal plate. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a semiconductor device formed by bonding a semiconductor element to a ceramic circuit board.

  Conventionally, a copper-clad ceramic circuit board in which a copper plate is bonded to the surface of a ceramic substrate has been used as a substrate used for mounting a high-power electronic component such as a power module.

  This ceramic circuit board is produced by directly bonding or brazing copper to a ceramic substrate such as alumina or aluminum nitride.

  As disclosed in JP-A-52-37914, the direct bonding substrate is made of an oxygen-free copper plate by using a copper plate containing oxygen or heating in an oxidizing atmosphere using an oxygen-free copper plate. After copper oxide is generated on the surface, the copper plate and the alumina substrate are stacked and heated in an inert atmosphere to form a composite oxide of copper and aluminum at the interface between the copper plate and the alumina substrate. Join.

  In the case of a copper / aluminum nitride direct bonding substrate, as disclosed in, for example, Japanese Patent Laid-Open No. 3-93687, an aluminum nitride substrate is treated in advance at a temperature of about 1000 ° C. to generate an oxide on the surface. Then, the copper plate and the aluminum nitride substrate are bonded via the oxide layer. The joining method using such an oxide layer deteriorates the thermal conductivity of the metal-bonded ceramic substrate because the oxide itself does not necessarily have a good thermal conductivity.

  In addition, when soldering copper to alumina or aluminum nitride, a low melting point brazing material or an alloy element for lowering the melting point or an alloy element for improving the wetting with ceramics is added between the copper plate and the ceramic circuit board. Join with the brazing filler metal. Although the copper / ceramic circuit board as described above is widely used, there are some problems in manufacturing and practical use. Among them, the most serious problem is a failure due to electrical continuity between the front and back of the substrate when a crack occurs in the ceramic substrate during mounting and use of the electronic component.

  The occurrence of such cracks is due to the fact that the thermal expansion coefficient of copper is about an order of magnitude greater than that of ceramics. That is, when these are joined, they are heated to close to 1000 ° C., and therefore, when they are cooled from the joining temperature to room temperature, a great thermal stress is generated inside the ceramic circuit board due to the difference in thermal expansion coefficient.

  Further, due to heat generation and cooling during use, the temperature of the ceramic circuit board changes, and a fluctuating thermal stress is generated, which may cause a crack in the ceramic substrate.

  At present, instead of copper as described above, aluminum having a thermal expansion coefficient relatively close to that of ceramics is used for bonding. In addition, since aluminum has a low melting point, it can be bonded at a lower temperature than copper, and cracking due to shrinkage during cooling can be reduced. Furthermore, as described above, since aluminum is a softer metal than copper, the aluminum plate itself can flexibly cope with the thermal expansion associated with heat generation and cooling during use, reducing the stress that causes cracks in the ceramic substrate. It is also possible.

  However, in recent years, with the development of power modules for electric vehicles, there has been a demand for the development of circuit boards that are further excellent in heat cycle resistance. For example, in the case of use conditions such as an electric vehicle where the temperature change is large and the vibration is large, the circuit board is required to have a heat cycle resistance of 500 times or more. In the copper / ceramic circuit board currently used, it is impossible to meet such a demand, and even in a normal aluminum / ceramic circuit board which is said to have relatively few cracks. It is difficult to withstand the cold cycle.

  Also, semiconductor elements such as Si pellets are bonded to the metal plate portion of the ceramic circuit board. However, if solder nests are formed in the solder during bonding, heat conduction is inhibited and heat is accumulated. Problems occur, such as delamination and peeling of the semiconductor element and the ceramic circuit board during the cooling and heating cycle.

  An object of the present invention is to provide a semiconductor device in which a semiconductor element is securely bonded to a metal plate portion of a ceramic circuit board, and problems such as defective thermal resistance and peeling are suppressed.

The semiconductor device of the present invention includes a ceramic substrate, a metal plate directly bonded to the surface of the ceramic substrate, mainly made of aluminum, and a semiconductor element bonded on the metal plate. A plurality of grooves are provided in a portion of the main surface to which the semiconductor element is bonded, and the plurality of grooves have a depth that is 1/6 or more of the thickness of the portion that becomes the mounting surface of the metal plate. / 6 or less, a width of 0.05 mm or more and 1.0 mm or less, an interval between adjacent grooves of 0.05 mm or more and 5.0 mm or less, and a length longer than the semiconductor element, the metal plate and the semiconductor element Are bonded by solder, and generation or growth of solder nests can be suppressed, and defective thermal resistance can be suppressed .

  In the semiconductor device of the present invention described above, it is preferable that the ceramic substrate is mainly made of at least one material selected from the group consisting of alumina, aluminum nitride, and silicon nitride. Moreover, for example, an Al—Si alloy plate or the like can be used as the metal plate mainly made of aluminum.

  The semiconductor device of the present invention includes a ceramic substrate, a metal plate directly bonded to the surface of the ceramic substrate, mainly made of aluminum, and a semiconductor element bonded on the metal plate. By providing a plurality of grooves in the portion where the semiconductor element is bonded on the main surface of the soldering layer, it is possible to prevent the formation of solder nests in the solder layer and prevent thermal conduction from being hindered during soldering, Separation due to a difference in thermal stress between the semiconductor element and the metal plate can be suppressed.

  The depth of the plurality of grooves is 1/6 or more and 5/6 or less of the thickness of the portion to be the mounting surface of the metal plate, the width is 0.05 mm or more and 1.0 mm or less, and the distance between adjacent grooves is 0.05 mm or more. By making the length 5.0 mm or less and longer than the Si pellet, the formation of solder nests in the solder layer can be further suppressed to prevent thermal conduction from being inhibited. Separation from the plate can be suppressed.

  In addition, by using as a ceramic substrate a material mainly composed of at least one material selected from the group consisting of alumina, aluminum nitride, and silicon nitride, the characteristics such as strength and thermal conductivity required for semiconductor devices are improved. Can be made.

  Furthermore, by using a metal plate mainly made of aluminum as an Al—Si alloy plate, the bonding strength between the aluminum plate and various ceramics can be improved. Therefore, it is possible to further suppress the occurrence of cracks in the ceramic plate by applying it to the aluminum plate improved in shape as described above.

  The semiconductor device of the present invention can suppress the formation of solder nests in the solder used when bonding the semiconductor element to the ceramic circuit board, and can suppress thermal resistance defects and peeling.

The external view which shows an example at the time of providing a thin part inside the outer periphery part of a metal plate. Sectional drawing which shows an example at the time of providing a thin part inside the outer periphery part of a metal plate. The external view which shows an example at the time of providing a hole in the outer periphery part inside a metal plate. The top view which expanded a part of FIG. The top view which shows an example at the time of making the shape of a hole into a rectangle. Sectional drawing which shows an example at the time of providing a hole inside the outer periphery part of a metal plate. Sectional drawing which shows the other example of the shape of the depth direction of a hole. Sectional drawing which shows an example at the time of making a hole into a through-hole. The external view which shows an example at the time of providing a discontinuous groove | channel in the outer periphery part inside a metal plate. The top view which expanded a part of FIG. Sectional drawing which shows an example of the cross-sectional shape of a groove | channel. Sectional drawing which shows the other example of the cross-sectional shape of a groove | channel. 1 is an external view illustrating an example of a semiconductor device of the present invention. FIG. 10 is a cross-sectional view illustrating an example of a semiconductor device of the invention. The figure showing the stress distribution of the reference example 1 after a thermal cycle test implementation. The figure showing the stress distribution of the reference example 2 after a thermal cycle test implementation. The figure showing the stress distribution of the reference example 3 after a thermal cycle test implementation. Schematic which showed an example of the aluminum plate used for Examples 1-4.

  FIG. 1 shows an example of a ceramic circuit board.

  The ceramic circuit board 1 is obtained, for example, by bonding an aluminum plate 3 to a ceramic board 2. At this time, when the outer peripheral edge portion of the aluminum plate 3 is 3a, the inner side of the outer peripheral edge portion is the thin portion 3b. Here, the inner side of the outer peripheral edge is a portion of a constant distance from the outer peripheral edge toward the center.

  For example, when directly joining an aluminum plate to a ceramic plate, the aluminum plate is heated to the melting point or more of the aluminum plate, but by providing a thin portion inside the outer peripheral edge of the aluminum plate, the stress generated in the outer peripheral edge of the aluminum plate is reduced to aluminum. Absorption is caused by plastic deformation of the thin portion of the plate, and it is possible to suppress the occurrence of cracks in the ceramic plate. In addition, not only when joining the aluminum plate and ceramic plate, but also when using them after joining them, thermal stress is generated by the thermal cycle. It is possible to suppress the occurrence of cracks in the ceramic plate by absorbing the thin plate portion of the aluminum plate due to plastic deformation.

  As the shape of the thin portion 3b, for example, as shown in FIG. 2, the surface of the aluminum plate that is not bonded to the ceramic plate is shaved to provide a step. Examples of a method for forming such a thin portion 3b include a method of processing by etching or the like in addition to a method of mechanically processing. The thin portion 3b may be formed after joining the ceramic plate and the aluminum plate, but by forming it before joining the ceramic plate, it is possible to suppress the occurrence of cracks in the ceramic plate due to stress during joining. Therefore, it is more effective.

  For example, if the length from the outer peripheral edge of the aluminum plate is W and the thickness of the thin portion is T, W is 0.3 mm to 1.0 mm, and T is aluminum. It is preferably 1/6 or more and 5/6 or less of the thickness of the mounting surface of the plate. If the length W from the outer peripheral edge of the thin wall portion is less than 0.3 mm, a sufficient stress relaxation effect cannot be obtained, causing cracks. Moreover, what was formed in the part exceeding 1.0 mm has an insufficient stress relaxation effect, and will also reduce a mounting area. If the thickness T of the thin portion 3b is less than 1/6 of the thickness of the mounting surface of the aluminum plate, the strength of the aluminum plate may be reduced. If it exceeds 5/6, the stress relaxation effect will not be recognized.

  Next, an example of another ceramic circuit board is shown in FIG.

  As shown in FIG. 3, the ceramic circuit board 4 has a plurality of holes 5 formed on the inner side of the outer peripheral edge of the aluminum plate 3 opposite to the joint surface with the ceramic substrate 2.

  As a preferred embodiment of the ceramic circuit board described above, the plurality of holes 5 are formed linearly along the outer peripheral edge of the aluminum plate 3, for example. The transverse shape of the hole may be circular as shown in FIG. 4 or rectangular as shown in FIG. Such a plurality of holes may be formed by etching, or may be formed by pressing using a mold. Thus, by forming a plurality of holes in a straight line, the stress concentration on the outer peripheral edge of the aluminum plate can be efficiently reduced.

  As the size of such a hole, when the hole is a circle as shown in FIG. 4, D is preferably 0.3 mm or more and 1.0 mm or less, where D is the diameter of the hole. Further, when L is the distance between the holes, L is preferably 0.3 mm or more and 1.0 mm or less. Furthermore, when the distance from the outer peripheral edge of the metal plate to the hole is Z, Z is preferably 0.3 mm or more.

  If the diameter of the hole is less than 0.3 mm, the stress cannot be sufficiently relaxed, and if it exceeds 1.0 mm, the strength of the aluminum plate is reduced and the mounting area is also reduced. If the distance between the holes is too large, the stress relaxation effect may not be sufficiently obtained. If it is too small, the aluminum plate may be deformed when the holes are processed. Further, if the distance Z from the outer peripheral edge of the metal plate to the outer peripheral edge of the hole is less than 0.3 mm, the stress relaxation effect may not be sufficient.

  The plurality of holes described above may be non-through holes 5a as shown in FIGS. 6 and 7, or may be through holes 5b as shown in FIG. For example, the non-through hole 5a can be easily formed by pressing or the like, which is effective for reducing the number of manufacturing steps. Further, when the DBA method is applied, the through hole 5b can also function as a discharge hole for gasified oxygen or the like without contributing to bonding.

  When the plurality of holes are non-through holes 5a, the shape in the depth direction may be a substantially uniform shape as shown in FIG. 6, or an inverted conical shape as shown in FIG. Also good.

  Next, another example of the ceramic circuit board will be described.

  As shown in FIG. 9, the ceramic circuit board 6 has a discontinuous groove 7 formed on the inner side of the outer peripheral edge of the aluminum plate 3 on the side opposite to the joint surface with the ceramic substrate 2. By providing such a discontinuous groove 7, the stress generated at the outer peripheral edge of the aluminum plate 3 can be efficiently relaxed. Here, the inner side of the outer peripheral edge is a portion directed from the outer peripheral edge of the metal plate toward the center as shown in FIG. In the ceramic circuit board, the discontinuous grooves are preferably formed in a straight line. By forming the discontinuous grooves in a straight line in this manner, stress concentration can be more efficiently mitigated.

  FIG. 10 is an enlarged view of a part of the ceramic circuit board 6. Here, W represents the width of the single groove, E represents the length of the single groove, and Z represents the distance from the outer peripheral edge of the single groove.

  As the shape of each single groove constituting the discontinuous grooves, that is, the width W and length E of the single groove and the distance Z from the outer peripheral edge, the width W is 0.05 mm or more and 1.0 mm or less, and the length E is It is preferable that the distance Z from the outer peripheral edge portion is 20 mm or less and 0.3 mm or more.

  When the width W is less than 0.05 mm, the stress cannot be sufficiently relaxed, and when it exceeds 1.0 mm, the strength of the aluminum plate is reduced and the mounting area is also reduced. Moreover, when the length E of each single groove exceeds 20 mm, there is a possibility that deformation of the aluminum plate cannot be sufficiently suppressed as the groove non-forming region decreases. Further, if the distance Z from the outer peripheral edge is less than 0.3 mm, a sufficient stress relaxation effect may not be obtained.

  Further, the longitudinal cross-sectional shape of the discontinuous grooves 7 may be substantially uniform in the depth direction as shown in FIG. 11, or may be an inverted triangle shape as shown in FIG. However, the depth H is preferably from 1/6 to 5/6 of the thickness of the mounting surface of the aluminum plate. If the depth H is less than 1/6 of the thickness of the mounting surface of the aluminum plate, the stress dispersion effect may be insufficient, and if the depth H exceeds 5/6 of the thickness of the mounting surface of the aluminum plate, It tends to cause a decrease in strength of the aluminum plate.

  Further, the ceramic substrate used for the ceramic circuit substrate is preferably made of at least one material selected from the group consisting mainly of alumina, aluminum nitride and silicon nitride.

  Next, an embodiment of the semiconductor device of the present invention will be described.

  FIG. 13 is a view showing the appearance of the semiconductor device of the present invention. FIG. 14 is a view showing a cross-sectional shape of the semiconductor device of the present invention.

  As shown in FIG. 13, the semiconductor device 8 of the present invention includes an aluminum plate 3 bonded to a ceramic substrate 2 such as aluminum nitride, and a solder layer 9 on the surface of the aluminum plate 3 where the ceramic substrate 2 is not bonded. In the semiconductor device 8 composed of the semiconductor elements 10 joined together, a plurality of grooves 11 are provided on the surface of the aluminum plate 3 to which the semiconductor elements 10 are joined.

  Here, H indicates the depth of the groove formed in the aluminum plate, W indicates the width of the groove, and L indicates the distance between the grooves.

  Conventionally, when a semiconductor element is soldered to an aluminum plate, a gas is caught in the solder portion to form a solder nest. Since the solder nest present in the solder portion causes a thermal resistance failure, it is preferably removed.

  In the semiconductor device of the present invention, by providing the groove 11 on the surface of the aluminum plate 3 on which the solder layer 9 is formed in this way, the gas that causes the formation of the solder nest is discharged from the groove 11 and the solder nest is formed. Even if the generation of the solder nest is suppressed, the formation of the solder nest larger than the groove 11 can be suppressed by providing the groove 11. Therefore, in the semiconductor device of the present invention, it is possible to suppress the thermal resistance failure due to the solder nest and to suppress variations in the thermal resistance and the like in each semiconductor device.

  The depth H of the groove formed in such an aluminum plate is 1/6 or more and 5/6 or less of the thickness of the aluminum plate, the width W is 0.05 mm or more and 1.0 mm or less, and the distance L between adjacent grooves is It is preferable that it is 0.05 mm or more and 5.0 mm or less.

  When the depth of the groove is less than 1/6 of the thickness of the aluminum plate, the gas discharge effect is reduced and solder nests are easily formed. When the depth of the groove exceeds 5/6 of the thickness of the aluminum plate, the strength of the aluminum plate It will cause a decline. Further, if the width W is less than 0.05 mm, the gas discharge effect is lowered, and solder nests are easily formed. If the width W exceeds 1.0 mm, the gas discharge effect is lowered and the strength of the aluminum plate is reduced. I will invite you. Further, if the gap L between the grooves is less than 0.05 mm, the strength of the substrate is lowered, and if the gap L exceeds 5.0 mm, the gas discharge effect is lowered, and a solder nest is formed. It becomes easy to be done.

  Furthermore, the ceramic substrate used in the semiconductor device of the present invention is preferably mainly composed of at least one material selected from alumina, aluminum nitride, silicon nitride and the like. The metal plate mainly made of an aluminum plate is not particularly limited as long as the aluminum content is 50 wt% or more. High purity aluminum having a purity of 99% or more, Al—Mg alloy, Al—Mn alloy, Al—Si alloy Various aluminum alloy plates can be applied. Among them, it is particularly preferable to use an Al—Si alloy plate because an Al—Si alloy is easily eutectic bonded to various ceramics. The Si content is preferably 0.001 to 40 wt%. For example, in ceramics that do not contain Si as a main component, such as alumina and aluminum nitride, the Si content in the aluminum plate is preferably 5 to 30 wt%. Thus, in the ceramic containing Si as a main component, the Si content in the aluminum plate is preferably 0.01 to 15 wt%.

  Hereinafter, an example of a method for manufacturing a semiconductor device of the present invention will be described.

  For example, an aluminum plate is bonded to a ceramic substrate made of aluminum nitride by the DBA method. Further, a plurality of grooves longer than the length of the semiconductor element are formed by a method such as etching in a portion to which the semiconductor element such as a Si pellet on the surface of the bonded aluminum plate to which the ceramic substrate is not bonded is to be bonded. A semiconductor element is bonded to the surface on which the groove is formed using solder. In this way, by joining the semiconductor element to the portion where the groove is provided in advance using the solder, it is possible to suppress the removal or growth of the solder nest generated in the solder portion and suppress the thermal resistance failure.

  In ceramic circuit boards, an aluminum plate with grooves provided in advance by etching or pressing may be joined directly to the ceramic substrate, or aluminum is melted and applied to the ceramic substrate, and then grooves are formed by etching or the like. The semiconductor elements may be joined with solder.

  Next, specific examples of the present invention and evaluation thereof will be described.

Reference Examples 1-3, Comparative Example 1
Reference example 1
An aluminum plate having a thickness of 0.5 mm and a purity of 99% or more was prepared, and the thickness of a portion from the outer peripheral edge portion of this aluminum plate to 1 mm was set to 0.25 mm by etching. Thereafter, this aluminum plate was directly bonded to an aluminum nitride substrate having a thickness of 0.7 mm to produce a ceramic circuit substrate.

Reference example 2
An aluminum plate having a thickness of 0.5 mm and a purity of 99% or more was prepared, and a plurality of holes were provided inside the outer peripheral edge of the aluminum plate by etching. The hole diameter was 0.5 mm, the interval between the holes was 0.5 mm, and the edge of the hole was 0.5 mm from the outer peripheral edge. This aluminum plate was directly joined to an aluminum nitride substrate having a thickness of 0.7 mm to produce a ceramic circuit board.

Reference example 3
An aluminum plate having a thickness of 0.5 mm and a purity of 99% or more was prepared, and a plurality of grooves were provided inside the outer peripheral edge of the aluminum plate by etching. The depth of the groove was 0.25 mm, the width of the groove was 0.05 mm, and the edge of the groove was 0.5 mm from the outer peripheral edge. This aluminum plate was directly joined to an aluminum nitride substrate having a thickness of 0.7 mm to produce a ceramic circuit board.

Comparative Example 1
An aluminum plate having a thickness of 0.5 mm and a purity of 99% or more was prepared, and this aluminum plate was directly bonded to an aluminum nitride substrate having a thickness of 0.7 mm to produce a ceramic circuit board.

  Cooling cycle test (TCT: 233K × 30 minutes → RT × 10 minutes → 398K × 30 minutes → RT × 10 minutes is 1 for the ceramic circuit boards of Reference Examples 1 to 3 and Comparative Example 1 manufactured as described above. (RT is room temperature), and the stress distribution at the time of applying the thermal cycle was measured.

  The results of each reference example and comparative example are shown in FIGS.

  As is clear from each figure, any thin plate, hole, or groove provided inside the outer peripheral edge of the aluminum plate alleviates the stress generated at the outer peripheral edge, and stress near the outer peripheral edge of the aluminum plate. Can be seen to be lower.

  On the other hand, when the aluminum plate was not processed at all, it was found that a large stress was generated at the outer peripheral edge of the aluminum plate and there was a risk of occurrence of cracks and the like.

Examples 1 to 4 and Comparative Example 2
Examples 1-4
An aluminum plate having a thickness of 0.5 mm, a length of 3 cm × a width of 3 cm, and a purity of 99% or more was prepared, and a plurality of grooves were provided at the center of the aluminum plate as shown in FIG. The depth (H), width (W), length (E) and interval (L) of the grooves were adjusted as shown in Table 1. Moreover, the groove | channel was not provided in the part 5 mm from both the edge parts of the direction perpendicular | vertical to a groove direction.

  Furthermore, an aluminum nitride substrate was directly bonded to the surface of the aluminum plate where no groove was provided, and a Si pellet was bonded to the center of the surface where the groove was provided using solder to produce a semiconductor device.

  A Si pellet having a thickness of 0.5 mm and a length of 2 cm × width of 2 cm was used.

Comparative Example 2
An aluminum plate having a thickness of 0.5 mm, a length of 3 cm x a width of 3 cm, and a purity of 99% or more is used, and one side of this aluminum plate is bonded with Si pellets without soldering, and the other side is joined. Then, an aluminum nitride substrate was directly joined to produce a semiconductor device. The same Si pellet as that used in Examples 1 to 4 was used.

  Thus, the thermal resistance of the semiconductor device of Examples 1-4 and the comparative example 2 produced was measured.

  The evaluation results of thermal resistance in Examples 1 to 4 and Comparative Example 2 are shown in Table 1.

表１から明らかなように、実施例１〜４のようにＳｉペレットとの接合面に溝を設けたものは、いずれも熱抵抗不良が抑制されていることがわかった。特に、溝の深さ、幅、長さ、間隔を、本発明における好ましい値としたものは、熱抵抗不良が大幅に抑制されていることがわかった。

As is clear from Table 1, it was found that all of the samples provided with grooves on the joint surface with the Si pellet as in Examples 1 to 4 have suppressed thermal resistance defects. In particular, it was found that when the groove depth, width, length, and interval were set to preferred values in the present invention, the thermal resistance failure was greatly suppressed.

  On the other hand, it was found that in Comparative Example 2 in which the Si pellet and the aluminum plate were joined without providing a groove on the joint surface of the aluminum plate with the Si pellet, a thermal resistance failure occurred.

  From the above results, it was confirmed that by providing a plurality of grooves on the Si pellet joint surface of the aluminum plate as in the present invention, generation or growth of solder nests can be suppressed and thermal resistance defects can be significantly suppressed. It was.

Reference Examples 4-6
What changed the aluminum plate of the reference example 1 into the Al-10wt% Si board was Reference example 4, what changed the aluminum nitride substrate of the reference example 1 into the silicon nitride substrate was Reference example 5, and the aluminum plate of the reference example 1 was Al A reference example 6 was obtained by changing the aluminum nitride substrate to a silicon nitride substrate instead of the -10 wt% Si plate.

  For such a ceramic circuit board, the peel strength of the aluminum plate and the thermal cycle test (TCT) are stricter than usual with one cycle of 233 K × 30 minutes → RT × 10 minutes → 398 K × 30 minutes → RT × 10 minutes. Under the conditions, the presence or absence of cracks in the ceramic substrate when 1000 cycles and 2000 cycles were performed was confirmed.

  For comparison, the same measurement was performed on the ceramic circuit board of Comparative Example 1. The results are shown in Table 2.

表２に示されるように、アルミニウム板にＳｉを含有させた場合のほうがピール強度が向上していることがわかる。

As shown in Table 2, it can be seen that the peel strength is improved when Si is contained in the aluminum plate.

  Moreover, even if it sees a TCT test result, the thing of the reference examples 4-6 is test conditions 233Kx30 minutes-> RTx10 minutes-> 398Kx30 minutes-> RTx10 minutes, despite severe conditions than usual. The generation of cracks in the ceramic substrate was not confirmed until 1000 cycles.

  On the other hand, some peeling was confirmed in the comparative example. This is because the stress relaxation is not performed because there is no thin part in the outer peripheral part of the aluminum plate. In addition, the notation of “somewhat” in the TCT test indicates that some cracking phenomenon has been confirmed.

  Furthermore, when the aluminum nitride substrate and the silicon nitride substrate were compared, it was found that the silicon nitride substrate (Reference Examples 5 and 6) exhibited superior TCT test characteristics.

DESCRIPTION OF SYMBOLS 1 ... Ceramic circuit board 2 ... Ceramic substrate 3 ... Aluminum plate 3a ... Outer peripheral edge part 3b ... Thin part 5 ... Hole 7 ... Groove 9 ... Solder layer 10 ... Semiconductor element 11 ... Groove

Claims (3)

In a semiconductor device comprising a ceramic substrate, a metal plate that is directly bonded to the surface of the ceramic substrate, mainly made of aluminum, and a semiconductor element bonded on the metal plate,
A portion of the main surface of the metal plate to which the semiconductor element is bonded is provided with a plurality of grooves, and the depth of the plurality of grooves is 1 of the thickness of the portion that becomes the mounting surface of the metal plate. / 6 or more and 5/6 or less, the width is 0.05 mm or more and 1.0 mm or less, the distance between adjacent grooves is 0.05 mm or more and 5.0 mm or less, and the length is longer than the semiconductor element, A semiconductor device, wherein the semiconductor element is bonded to the semiconductor element by soldering, and the generation or growth of solder nests can be suppressed and thermal resistance defects can be suppressed . The ceramic substrate is alumina, claim 1 Symbol mounting semiconductor device characterized by comprising mainly of at least one material selected from the group consisting of aluminum nitride and silicon nitride. 3. The semiconductor device according to claim 1, wherein the metal plate mainly made of aluminum is an Al—Si alloy plate.

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