JP6264822B2 - Power module substrate with heat sink and manufacturing method thereof - Google Patents

Description

  The present invention relates to a power module substrate with a heat sink used in a semiconductor device for controlling a large current and a high voltage, and a method for manufacturing the same.

  As a power module, a power module substrate with a heat sink in which an aluminum plate is bonded onto a ceramic substrate such as aluminum nitride and an aluminum heat sink is bonded to the other side through an aluminum plate is used. .

Conventionally, a power module substrate with a heat sink has been manufactured as follows.
First, an aluminum plate is laminated on one surface and the other surface of the ceramic substrate via a brazing material suitable for joining the ceramic substrate and the aluminum plate to the surface of the ceramic substrate, and the brazing material is pressed with a predetermined pressure. The power module substrate is manufactured by joining the ceramic substrate and the aluminum plates on both sides by heating and cooling to a temperature equal to or higher than the temperature at which the material melts.

Next, a heat sink is laminated on the aluminum plate on the other side of the power module substrate via a brazing material suitable for joining the aluminum plate and the heat sink, and the brazing material is melted while being pressed at a predetermined pressure. Heat to above temperature and cool. Thereby, an aluminum plate and a heat sink can be joined and a power module substrate with a heat sink can be manufactured.
In addition, the aluminum plate bonded to one surface side of the power module substrate with a heat sink thus configured is formed as a circuit layer, and electronic components such as power elements are placed on the circuit layer via a solder material. Installed.

However, in the joining of members having different thermal expansion coefficients such as a ceramic substrate and an aluminum plate, warpage occurs due to thermal contraction during cooling after joining.
As a countermeasure against this warp, Patent Document 1 describes controlling the warp amount at high temperature when soldering a chip, a terminal, a heat sink, etc., and the warp amount when the ceramic circuit board is returned to room temperature. Has been.

  Further, in Patent Document 2, a circuit board having a warp in which the circuit metal plate becomes a concave surface is manufactured by joining the circuit metal plate and the metal heat sink while bending the ceramic substrate. In general, when a module is formed using a circuit board, the module is joined to a heat sink so as to be planar and fixed to a fixing component. Therefore, by forming a concave warp on the circuit metal plate side of the circuit board, when the circuit board is fixed flat, compressive stress remains on the circuit board, and when assembled into a module or under actual use Describes that the generation and growth of cracks can be reduced.

Further, in Patent Document 3, warpage occurring during solder reflow between a ceramic circuit board and a heat sink is mainly governed by the volume ratio and the thickness ratio of the metal heat sink and metal circuit board. It is described that a preferable warp shape can be realized during heating by setting the range.
As described above, the warpage generated in the circuit board can be suppressed by adjusting the thickness of the heat sink side aluminum plate and the heat sink that form the metal layer with the ceramic substrate as the neutral axis.

JP 2003-273289 A Japanese Patent Laid-Open No. 10-247763 JP 2006-245437 A

However, what is desired for a power module substrate is to reduce warpage to satisfy the required specifications of the power module. As described in Patent Document 1, even if the warpage is controlled as a power module substrate, the warpage must be reduced as a power module. Further, in a power module substrate with a heat sink in which the power module substrate and the heat sink are joined, a convex warp occurs with the circuit layer on the upper side during normal manufacturing.
However, in use, when the power module substrate with a heat sink is fastened to the cooler via grease or the like, from the viewpoint of maintaining good adhesion between the power module substrate with the heat sink and the cooler, the cooler It is desired that the warp is a convex warp rather than a concave warp (convex warp on the circuit layer side). In addition, even after the fastening to the cooler, it is desired that the power module substrate with a heat sink is less warped and deformed in the heat treatment process such as soldering of the semiconductor element.

  The present invention has been made in view of such circumstances, and while reducing the warpage that occurs during the manufacture of a power module substrate with a heat sink and suppressing the occurrence of warpage in the heat treatment process, It aims at providing the manufacturing method.

The present invention provides a power module substrate in which a circuit layer is disposed on one surface of a ceramic substrate, and a metal layer made of aluminum having a purity of 99% or more is disposed on the other surface of the ceramic substrate, and the power module A power module substrate with a heat sink, comprising: a heat sink that is bonded to the metal layer of the substrate and is formed in a flat plate shape using an aluminum alloy having a yield stress greater than that of the metal layer, the maximum length of the heat sink Is L, the ratio of warpage of the heat sink is Z, and the convex deformation on the joining surface side of the heat sink is the positive amount of warpage, the ratio Z / L of L to Z at 25 ° C. is −0.005. The ratio Z / L when heated to 280 ° C. is in the range of −0.005 or more and 0.005 or less. The ratio Z / L at the time of cooling to 25 ° C. after heating is in the range of −0.005 to 0.005.

If the ratio Z / L is less than -0.005 or exceeds 0.005 when the temperature is set, the solder or semiconductor element may be misaligned in the process of soldering the electronic component such as a semiconductor element to the circuit layer. Cheap. In addition, there is a risk that the reliability of the solder joint or the substrate due to the destruction of the semiconductor element itself or thermal cycle may be caused.
On the other hand, the power module substrate with a heat sink in which the ratio Z / L is in the range of −0.005 or more and 0.005 or less at the time of the above temperature setting reduces the warpage that occurs at the time of manufacture, and the warpage of the power module due to the heat treatment process. Since deformation is suppressed, it is possible to improve the workability in the soldering process of the semiconductor element and to improve the board reliability due to the heat cycle load.

  In addition, since the metal layer is made of aluminum having a relatively low deformation resistance and a purity of 99% or more, the thermal stress generated in the ceramic substrate under a thermal cycle load can be relaxed, and the ceramic substrate is cracked. Can be suppressed.

In the power module substrate with a heat sink of the present invention, when the temperature is changed from 25 ° C. to 280 ° C., the difference ΔZ / L between the maximum value and the minimum value of the ratio Z / L is 0.005 or less. Good.
Since the difference ΔZ / L between the maximum value and the minimum value of the ratio Z / L in the temperature change from 25 ° C. to 280 ° C. is 0.005 or less and deformation is suppressed, the soldering of the semiconductor element is further improved. It is possible to improve workability in the process and to improve the substrate reliability due to thermal cycle load.

The present invention is a method of manufacturing a power module substrate with a heat sink, wherein the power module substrate and the heat sink are laminated when the power module substrate and the heat sink are joined, and the laminate is provided. Is pressed between 0.3 MPa and 10 MPa between the opposing surfaces of the two pressure plates formed with convex surfaces or concave surfaces having a curvature radius of 1000 mm or more and 6000 mm or less on the opposing surfaces, and the joint surface of the heat sink becomes a concave warp. It heats in the state which produced the deformation | transformation to perform, and cools in the state which produced the said deformation | transformation.

The heat sink is formed of a material having a high yield stress with respect to the metal layer, and when the heat sink and the power module substrate are joined, the laminate of the heat sink and the power module substrate is placed on the side opposite to the heat sink in the stacking direction. In a state in which a concave warp is generated and cooled after holding for a predetermined time at a temperature equal to or higher than the temperature at which the brazing material melts, the brazing material is solidified in a shape along the concave shape, and the pressure state in the stacking direction is released. Thereafter, a bonded body having a circuit layer as an upper side and warping in a concave shape or having a small warping amount even in a convex shape can be obtained. In this case, in the joining temperature range of the brazing material, it is possible to cause a concave deformation in a state where each member is expanded to the maximum extent.
And, in the power module substrate with a heat sink bonded in this way, it is possible to reduce the warpage deformation that occurs at the time of manufacture, and to suppress the warpage deformation during the heat treatment process, and the workability in the element soldering process. And the reliability of the substrate due to thermal cycle load can be improved. Thereby, the freedom degree of a structure increases and it can further contribute to thickness reduction of the whole power module.

  ADVANTAGE OF THE INVENTION According to this invention, while reducing the curvature which arises at the time of manufacture of the board | substrate for power modules with a heat sink, generation | occurrence | production of the curvature in the heat processing process can be suppressed.

It is sectional drawing which shows the board | substrate for power modules with a heat sink of this invention. It is sectional drawing explaining the manufacturing process of a heat sink and the board | substrate for power modules. It is sectional drawing which shows one Embodiment of the power module using the board | substrate for power modules with a heat sink of this invention. It is sectional drawing which shows the state which has arrange | positioned the laminated body of a heat sink and the board | substrate for power modules in a pressurization apparatus.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In FIG. 1, the board | substrate 100 for power modules with a heat sink of this embodiment is shown. The power module substrate 100 with a heat sink includes a power module substrate 10 and a heat sink 30 bonded to the power module substrate 10.
In addition, as shown in FIG. 1 or 2, the power module substrate 100 with a heat sink has a maximum heat sink length L, a heat sink warp amount Z, and a convex deformation on the joint surface side of the heat sink. When the amount of positive warpage is set, the ratio Z / L between L and Z is in the range of −0.005 to 0.005, and the ratio Z / L when heated to 280 ° C. is −0.005. The ratio is in the range of 0.005 or less, and the ratio Z / L when cooled to 25 ° C. after the heating is in the range of −0.005 or more and 0.005 or less. Details of the ratio Z / L will be described later.

  Then, with respect to the power module substrate 100 with a heat sink, as shown in FIG. 3, a power module is manufactured by further mounting an electronic component 20 such as a semiconductor chip on the surface of the power module substrate 10. .

  In the manufacturing process of the power module substrate 100 with a heat sink, first, the power module substrate 10 is manufactured, and the power module substrate 10 is brazed to the top plate 32 of the heat sink 30, whereby the power module substrate 100 with a heat sink is mounted. Manufacturing.

  The power module substrate 10 includes a ceramic substrate 11, a circuit layer 12 and a metal layer 13 laminated on the ceramic substrate 11. Then, the electronic component 20 is soldered to the surface of the circuit layer 12 of the power module substrate. A heat sink 30 is attached to the surface of the other metal layer 13.

The ceramic substrate 11 is made of, for example, nitride ceramics such as AlN (aluminum nitride), Si ₃ N ₄ (silicon nitride), or oxide ceramics such as Al ₂ O ₃ (alumina). In this embodiment, AlN is used. Was used. Further, the thickness of the ceramic substrate 11 is set within a range of 0.2 to 1.5 mm, and in this embodiment is set to 0.635 mm.

The circuit layer 12 is made of aluminum having a purity of 99% by mass or more. According to JIS standards, aluminum in the 1000s, particularly 1N90 (purity 99.9% by mass or more: so-called 3N aluminum) or 1N99 (purity 99.99% by mass or more: So-called 4N aluminum) can be used. In addition to aluminum, aluminum alloy, copper, or copper alloy can also be used.
The metal layer 13 is made of aluminum having a purity of 99% by mass or more. According to JIS standards, aluminum in the 1000s, particularly 1N99 (purity 99.99% by mass or more: so-called 4N aluminum) can be used.
In this embodiment, the circuit layer 12 and the metal layer 13 are aluminum plates made of a rolled plate of aluminum (so-called 4N aluminum) having a purity of 99.99% or more, and the thickness thereof is 0.2 mm to 3.0 mm. The circuit layer 12 has a thickness of 0.6 mm, and the metal layer 13 has a thickness of 2.1 mm.

  The circuit layer 12, the metal layer 13, and the ceramic substrate 11 are joined by, for example, brazing. As the brazing material, an alloy such as Al-Si, Al-Ge, Al-Cu, Al-Mg, or Al-Mn is used.

  In addition, the electronic component 20 constituting the power module is formed on a Ni plating (not shown) formed on the surface of the circuit layer 12 with a Sn—Ag—Cu system, a Zn—Al system, a Sn—Ag system, a Sn—Cu system. Bonding is performed using a solder material such as Sn, Sn—Sb, or Pb—Sn. Reference numeral 21 in FIG. 1 indicates the solder joint layer. The electronic component 20 and the terminal portion of the circuit layer 12 are connected by a bonding wire (not shown) made of aluminum.

The heat sink 30 bonded to the power module substrate 10 is made of an aluminum alloy having a high yield stress with respect to the metal layer 13, and for example, A3003, A5052, A6063, A7075, or the like is used. When the metal layer 13 is 4N aluminum, A1050 alloy or the like is used. In this embodiment, an A6063 aluminum alloy is used.
Here, as the heat sink, a plate-like heat sink, a cooler in which a refrigerant circulates inside, a cold liquid with fins formed thereon, an air-cooled heat radiator, a heat pipe, and the like intended to lower the temperature by heat dissipation Metal parts are included.

Next, a method for manufacturing the power module substrate 100 with a heat sink will be described.
First, as the circuit layer 12 and the metal layer 13, 99.99 mass% or more of pure aluminum rolled sheets are prepared, and these pure aluminum rolled sheets are brazed on one surface and the other surface of the ceramic substrate 11, respectively. The power module substrate 10 in which a pure aluminum rolled plate is bonded to one surface and the other surface of the ceramic substrate 11 is manufactured by laminating the film through the pressure and heating. In addition, this brazing temperature is set to 600 degreeC-655 degreeC.

To join the heat sink 30 to the power module substrate 10 thus configured, first, as shown in FIG. 4, a jig constituted by two pressure plates 110 and columns 111 provided at the four corners thereof. 112, the heat sink 30 and the power module substrate 10 are arranged between the pressure plates 110.
The two pressure plates 110 of the jig 112 are obtained by laminating carbon plates on the surface of a stainless steel material. The opposing surfaces 110a and 110b of the pressure plate 110 are respectively connected to the power module substrate 10 of the heat sink 30. It is formed in a concave surface or a convex surface having a curved surface having a curvature radius R of 1000 mm or more and 6000 mm or less so that the bonding surface 30a is concave. In this embodiment, since the curvature radius R is set to 1000 mm or more and 6000 mm or less, warpage occurring during manufacturing is reduced, and warpage deformation of the power module due to the heat treatment process can be suppressed.
And the screw | thread is cut at the both ends of the support | pillar 111, and the nut 113 is fastened so that the pressurization board 110 may be pinched | interposed. Further, an urging means 115 such as a spring for urging the pressurizing plate 110 downward is provided between the top plate 114 supported by the support column 111 and the pressurizing plate 110. It is adjusted by tightening the nut 113.

  In the manufacturing process of the power module substrate with a heat sink according to the present embodiment, the warpage generated in the power module substrate 100 with the heat sink by setting the power module substrate 10 and the heat sink 30 to the jig 112. Can be suppressed.

First, the heat sink 30 is placed on the pressure plate 110 having the concave surface 110a disposed on the lower side, and the power module substrate 10 is overlaid thereon via an Al—Si brazing foil (not shown). The stacked body of the heat sink 30 and the power module substrate 10 is placed between the pressure plate 110 having the convex surface 110b. At this time, the laminated body of the heat sink 30 and the power module substrate 10 is pressed in the thickness direction by the uneven surface of the pressure plate 110, and a state in which a deformation that causes the joint surface 30a of the heat sink 30 to be a concave warp is generated. Is done. Then, the heat sink 30 and the power module substrate 10 are heated in a pressurized state, thereby fixing the heat sink 30 and the metal layer 13 of the power module substrate 10 by brazing.
Note that brazing is performed in a vacuum atmosphere under conditions of a load of 0.3 MPa to 10 MPa and a heating temperature of 550 ° C. to 650 ° C.

Next, the joined body of the heat sink 30 and the power module substrate 10 is cooled to room temperature (25 ° C.) in a state where it is attached to the jig 112, that is, in a state where deformation is caused.
In this case, the joined body of the heat sink 30 and the power module substrate 10 is pressed in the thickness direction by the jig 112, and is restrained in a state in which the joint surface 30a of the heat sink 30 is deformed to have a concave warpage. Yes. For this reason, it seems that the shape of the joined body with cooling does not seem to change, but it is plastically deformed as a result of being pressed against the stress and restrained from deforming as a warp during cooling. Will occur.

  In the power module substrate 100 with a heat sink manufactured in this manner, the heat sink 30 is formed of a material having a high yield stress with respect to the metal layer 13, so that warpage is suppressed, and the maximum length of the heat sink 30 is L. When the warp amount of the heat sink 30 is Z and the convex deformation on the joint surface 30a side of the heat sink 30 is a positive warp amount, the ratio Z / L of L to Z at 25 ° C. is −0.005 or more 0 The ratio Z / L when heated to 280 ° C. is within the range of −0.005 to 0.005, and the ratio Z / L when cooled to 25 ° C. after the heating is within the range of 0.005 or less. It is within the range of −0.005 or more and 0.005 or less.

When the ratio Z / L is less than −0.005 or exceeds 0.005 when the temperature is set, the solder and the semiconductor element are likely to be misaligned in the process of soldering the semiconductor element to the circuit layer 12. In addition, there is a risk that the reliability of the solder joint or the substrate due to the destruction of the semiconductor element itself or thermal cycle may be caused.
On the other hand, the power module substrate with a heat sink in which the ratio Z / L is in the range of −0.005 or more and 0.005 or less at the time of the above temperature setting reduces the warpage that occurs at the time of manufacture, and the warpage of the power module due to the heat treatment process. Since deformation is suppressed, it is possible to improve the workability in the soldering process of the semiconductor element and to improve the board reliability due to the heat cycle load.

As described above, in the power module substrate with a heat sink of the present embodiment, the heat sink 30 is formed of a material having a high yield stress with respect to the metal layer 13, and the heat sink 30 is bonded to the heat sink 30 and the power module substrate 10. And the power module substrate 10 are cooled after being held for a predetermined time at a temperature equal to or higher than the temperature at which the brazing material melts, with the concave warpage occurring on the side opposite to the heat sink 30 in the stacking direction. Thus, even after the brazing material is hardened in a shape along the concave shape and the pressure state in the thickness direction (lamination direction) is released, the circuit layer 12 is warped concavely on the upper side, or even in the convex shape, the amount of warpage is small. A joined body is obtained. In this case, in the joining temperature range of the brazing material, it is possible to cause a concave deformation in a state where each member is expanded to the maximum extent. In the power module substrate with a heat sink of the present embodiment, the amount of warpage changes linearly in a temperature range of 25 ° C. to 280 ° C.
In the power module substrate 100 with a heat sink bonded in this way, it is possible to reduce the warpage deformation that occurs during manufacturing, and to suppress the warpage deformation during the heat treatment process, in the process of soldering the semiconductor element. It is possible to improve workability and to improve substrate reliability due to thermal cycle load. Thereby, the freedom degree of a structure increases and it can further contribute to thickness reduction of the whole power module.

Next, examples and comparative examples performed for confirming the effects of the present invention will be described.
In the manufacturing process of the power module substrate with a heat sink described above, a sample of the power module substrate with a heat sink in which the pressing load in the stacking direction of the power module substrate and the heat sink is changed and the power module substrate and the heat sink are joined. Several were manufactured. As for the bonding conditions of each sample, in Examples 1 to 7 and Comparative Examples 3 to 5, the curvature radius R of the concavo-convex surface uses a pressure plate described in Table 1, and in Comparative Examples 1 and 2, a flat pressure plate is used. Bonding was performed.
The power module substrate 10 constituting each power module substrate with a heat sink includes a circuit layer 12 made of 4N-Al of 68 mm × 68 mm and a thickness of 0.6 mm, and Table 1 of 68 mm × 68 mm and a thickness of 2.1 mm. The metal layer 13 made of the material described in (1) was bonded to the ceramic substrate 11 made of AlN having a size of 70 mm × 70 mm and a thickness of 0.635 mm using an Al—Si brazing material. As the heat sink 30, a rectangular plate made of the materials shown in Table 1 and having a size of 80 mm × 80 mm and a thickness of 5 mm was used.

And about the sample of the board | substrate for power modules with a heat sink, "change of the curvature amount by a temperature change", "solder position shift", "element position shift", and "element crack" were evaluated, respectively.
Further, the amount of warpage was measured at 25 ° C. (normal temperature), at 280 ° C. heating, and at 25 ° C. cooling after heating to 280 ° C. (at 25 ° C. cooling). And the change of the flatness of the back surface of the heat sink at each time point was evaluated as a warpage amount measured using a moire type three-dimensional shape measuring machine. The amount of warpage was defined as a positive amount of warpage that is convex on the side of the joint surface 30a of the heat sink 30.

The solder position shift is determined by placing solder (Sn—Ag—Cu system, melting point about 220 ° C.) on the circuit layer 12 of each sample and heating it to just below the melting point (200 ° C.). The presence or absence of the change was confirmed by producing 30 samples. In this case, the case where a positional deviation of 0.2 mm or more occurred was evaluated as “NG”, and the positional deviation of less than 0.2 mm was evaluated as “OK”.
In addition, the element position deviation was confirmed by measuring the soldering position after the element was soldered to the circuit layer 12 to determine whether or not the position deviation occurred. The case where a positional deviation of 0.2 mm or more occurred was evaluated as “NG”, and the positional deviation of less than 0.2 mm was evaluated as “OK”.
For element cracking, the element was soldered to the circuit layer 12 and then wiring was applied to check whether the element normally operated.
Table 1 shows the results. In Table 1, “◎” indicates that the “OK” ratio is 100%, “◯” indicates that the OK ratio is 90% or more, and “×” indicates that the “OK” ratio is less than 90%.

As can be seen from Table 1, the ratio Z / L at 25 ° C. is in the range of −0.005 to 0.005, and the ratio Z / L when heated to 280 ° C. is −0.005 to 0.005. In the samples of Examples 1 to 6, in which the ratio Z / L when cooled to 25 ° C. after the heating is within the range of −0.005 or more and 0.005 or less is “solder position shift” Good results were obtained in any of the evaluations of "", "element position deviation", and "element crack".
In Example 7 where the difference ΔZ / L between the maximum value and the minimum value of the ratio Z / L was 0.006, the evaluation of “solder position shift” and “element crack” was good. Some element misalignment occurred.
On the other hand, in Comparative Example 1 in which a low load was applied, the ratio Z / L during cooling at 25 ° C., 280 ° C., and 25 ° C. was outside the range of −0.005 to 0.005. .
Further, in Comparative Example 2 using a flat plate and Comparative Example 3 in which the radius of curvature R of the pressure plate is 8000 mm, the ratio Z / L at 25 ° C. falls outside the range of −0.005 or more and 0.005 or less. A lot of misalignment occurred. Further, in Comparative Example 4 in which the ratio Z / L at 280 ° C. was out of the range of −0.005 or more and 0.005 or less, many element cracks occurred.

  As described above, in the power module substrate 100 with a heat sink according to the present invention, it is possible to reduce warpage deformation that occurs during manufacturing, and to suppress warpage deformation during the heat treatment process, in the element soldering process. It is possible to improve workability and to improve substrate reliability due to thermal cycle load.

  In general, since warping occurs three-dimensionally, the diagonal length is the maximum length L in the case of a rectangular plate. Further, the warpage amount Z is the difference between the maximum value and the minimum value in the Z direction of the portion of the maximum length.

In addition, this invention is not limited to the thing of the structure of the said embodiment, In a detailed structure, it is possible to add a various change in the range which does not deviate from the meaning of this invention.
For example, in the above embodiment, the metal layer of the power module substrate and the heat sink are fixed by brazing. However, the present invention is not limited to brazing, and may be fixed by soldering, diffusion bonding, or the like.
Further, the ceramic substrate and the circuit layer, the ceramic substrate and the metal layer, and the metal layer and the heat sink are bonded by a transient liquid phase bonding method called a TLP bonding method (Transient Liquid Phase Diffusion Bonding). Also good.
In this transient liquid phase bonding method, the copper layer deposited on the surface of the circuit layer or the metal layer is interposed between the interface of the circuit layer or the metal layer and the ceramic substrate, or the interface of the metal layer and the heat sink. By heating, copper diffuses in the circuit layer or metal layer and aluminum, the copper concentration in the vicinity of the copper layer of the circuit layer or metal layer increases, the melting point decreases, and the bonding interface in the eutectic region of aluminum and copper A metal liquid phase is formed. If the temperature is kept constant in a state in which this metal liquid phase is formed, the metal liquid phase reacts with the ceramic substrate or the heat sink, and copper further diffuses into the aluminum. The copper concentration gradually decreases, the melting point increases, and solidification proceeds with the temperature kept constant. As a result, a strong bond between the circuit layer or metal layer and the ceramic substrate or between the metal layer and the heat sink can be obtained.

  Furthermore, in the above-described embodiment, the heat sink and the power module substrate are joined using the Al—Si brazing material, but may be joined using an Al—Si—Mg brazing material. In this case, it is not necessary to perform bonding in a vacuum atmosphere, brazing can be performed in an inert atmosphere such as nitrogen, and the heat sink and the power module substrate can be simply bonded.

DESCRIPTION OF SYMBOLS 10 Power module substrate 11 Ceramic substrate 12 Circuit layer 13 Metal layer 20 Electronic component 21 Solder joint layer 30 Heat sink 30a Joint surface 100 Power module substrate 110 with a heat sink Pressure plate 110a Concave surface 110b Convex surface 111 Column 112 Jig 113 Nut 114 Top plate 115 Energizing means

Claims (3)

A power module substrate in which a circuit layer is disposed on one surface of a ceramic substrate, and a metal layer made of aluminum having a purity of 99% or more is disposed on the other surface of the ceramic substrate, and the power module substrate A power module substrate with a heat sink, comprising: a heat sink that is bonded to a metal layer and is formed in a flat plate shape by an aluminum alloy having a yield stress greater than that of the metal layer, wherein the maximum length of the heat sink is L, When the amount of warpage of the heat sink is Z and the convex deformation on the bonding surface side of the heat sink is a positive amount of warpage, the ratio Z / L of L to Z at 25 ° C. is −0.005 or more and 0.005. The ratio Z / L when heated to 280 ° C. is in the range of −0.005 or more and 0.005 or less. The power module substrate with a heat sink, wherein the ratio Z / L when cooled to 5 ° C. is in the range of −0.005 to 0.005.   2. The heat sink according to claim 1, wherein the difference ΔZ / L between the maximum value and the minimum value of the ratio Z / L is 0.005 or less when the temperature is changed from 25 ° C. to 280 ° C. 3. Power module substrate. A method for manufacturing a power module substrate with a heat sink according to claim 1 or 2, wherein when the power module substrate and the heat sink are joined, the power module substrate and the heat sink are laminated, The laminated body is sandwiched between two opposing surfaces of two pressure plates each having a convex surface or a concave surface having a radius of curvature of 1000 mm or more and 6000 mm or less, and pressed at 0.3 MPa to 10 MPa to form a concave surface on the joining surface of the heat sink. A method for producing a substrate for a power module with a heat sink, comprising: heating in a state in which a deformation that causes warping is generated, and cooling in a state in which the deformation is generated.

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