JP6455056B2 - Manufacturing method and pressure device for power module substrate with heat sink - Google Patents

Description

The present invention relates to a method for manufacturing a power module substrate with a heat sink and a pressurizing device used in a semiconductor device that controls a large current and a high voltage.

  In an in-vehicle power module, for example, as shown in Patent Document 1, an aluminum layer is bonded to one surface of a ceramic substrate including aluminum nitride, and an aluminum layer is interposed on the other surface of the ceramic substrate. Similarly, a power module substrate with a heat sink to which a heat sink made of aluminum is bonded is used. In this power module substrate with a heat sink, an aluminum layer is first laminated on both sides of the ceramic substrate via a brazing material suitable for joining the ceramic substrate and the metal plate, and the brazing material melts while pressing at a predetermined pressure. It heats more than the temperature which carries out, and this joins a ceramic substrate and the aluminum layer of both surfaces. Next, a heat sink is laminated on the aluminum layer on the other surface of the ceramic substrate via a brazing material suitable for joining the metal plate and the heat sink, and the pressure exceeds a temperature at which the brazing material melts while pressing at a predetermined pressure. Until the aluminum layer and the heat sink are bonded. Further, in such a power module substrate with a heat sink, the aluminum layer on one surface of the ceramic substrate is formed as a circuit layer, and a semiconductor element is bonded onto the circuit layer via a solder material.

In this type of power module substrate, copper with excellent electrical characteristics is used for the metal plate that is the circuit layer, and aluminum is used for the metal plate that is the heat sink for the purpose of relieving the thermal stress between the ceramic substrate and the ceramic plate. There is.
For example, Patent Document 2 discloses a power module substrate with a heat sink in which a copper layer to be a circuit layer is bonded to one side of a ceramic substrate and a heat sink is bonded to the other side by brazing through an aluminum layer. Yes.
Also, for example, in Patent Document 3, an aluminum layer is brazed on both surfaces of a ceramic substrate, and then a copper layer that becomes a circuit layer is laminated on one side, and a copper layer that becomes a metal layer on the other side and further aluminum. A method of manufacturing a power module substrate with a heat sink by laminating heat sinks and solid-phase diffusion bonding each of them is disclosed.

Japanese Patent Laid-Open No. 2002-9212 JP 2013-229579 A JP2013-229545A

  However, when a power module substrate with a heat sink that uses a copper layer as a circuit layer is manufactured with the configuration described in Patent Document 2, a bonding temperature (about 600) is applied when the aluminum heat sink and the power module substrate are bonded. )), The warpage due to the difference in thermal expansion between the copper layer and the aluminum layer of the circuit layer occurs in the power module substrate, resulting in poor bonding due to a gap between the heat sink and the power module substrate. It was. In addition, even in the case of a power module substrate with a heat sink described in Patent Document 3, when a heat sink is joined after the power module substrate is manufactured, similarly, a bonding failure due to a gap occurs between the heat sink and the power module substrate. There is a problem that leads to a decline.

  The present invention has been made in view of such circumstances, and it is an object of the present invention to prevent a gap from being generated between the heat sink and the power module substrate when the heat sink is joined even if a copper layer is used as the circuit layer.

According to the method for manufacturing a power module substrate with a heat sink of the present invention, a circuit layer having a copper layer on at least a surface is bonded to one surface of a ceramic substrate, and an aluminum layer is included on the other surface of the ceramic substrate. Is a method of manufacturing a power module substrate with a heat sink by bonding a heat sink made of aluminum to the metal layer of the power module substrate to which the circuit layer is bonded, and pressing the circuit layer with a flat carbon sheet, And the joining surface of the said heat sink is formed in a convex shape according to the curvature of the said metal layer surface of the board | substrate for power modules produced at heat sink joining temperature, and it joins.

  In the present invention, the heat module bonding surface is formed in a convex shape and bonded in accordance with the warp of the metal layer surface of the power module substrate caused by the thermal expansion difference between copper and aluminum during heat sink bonding. It can join without generating a gap between the heat sink.

  In this case, in the method for manufacturing a power module substrate with a heat sink according to the present invention, the surface opposite to the bonding surface of the heat sink is pressed by a jig having the convex pressing surface to bond the heat sink to the metal layer. Good. The heat sink is joined while being warped in accordance with the warp of the metal layer surface of the power module substrate.

  Moreover, the manufacturing method of the board | substrate for power modules with a heat sink of this invention WHEREIN: The joining surface of a heat sink may be previously formed in the said convex shape, and you may make it join the heat sink to a power module board | substrate.

In the pressurizing device of the present invention, a circuit layer having at least a copper layer is bonded to one surface of a ceramic substrate, and a metal layer including an aluminum layer is bonded to the other surface of the ceramic substrate. The power module substrate is used to manufacture a power module substrate with a heat sink by joining a heat sink made of aluminum to the metal layer of the power module substrate, and a laminate of the power module substrate and the heat sink when the heat sink is joined. an apparatus for pressurizing the stacking direction has a flat carbon sheet for pressing the circuit layer, and the jig for pressing the heat sink, said power jig occurs at the heat sink junction temperature It is preferable to have a convex pressing surface that matches the warp of the metal layer surface of the module substrate.

According to the method for manufacturing a power module substrate with a heat sink and the pressurizing apparatus of the present invention, it is possible to obtain a good bondability between the power module substrate having a copper layer as a circuit layer and the heat sink, and to provide a heat sink with excellent thermal performance. A power module substrate can be manufactured.

It is sectional drawing which shows the manufacturing method of 1st Embodiment of the board | substrate for power modules with a heat sink of this invention in order of a process. It is sectional drawing which shows the structure which accumulated the board | substrate for power modules and the heat sink at the time of the heat sink joining process in 1st Embodiment. It is sectional drawing which shows the manufacturing method of 2nd Embodiment of the board | substrate for power modules with a heat sink of this invention in order of a process. It is sectional drawing similar to FIG. 2 in 2nd Embodiment of this invention. It is sectional drawing similar to FIG. 2 in 3rd Embodiment of this invention. It is sectional drawing similar to FIG. 2 in 4th Embodiment of this invention. It is a graph showing the relationship of the curvature by the temperature change of the board | substrate for power modules. It is a front view of the pressurizer used for the 1st joining process of the manufacturing method of the present invention. It is a front view of the pressurization apparatus used for the heat sink joining process of the manufacturing method of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
A power module substrate 14 with a heat sink of the first embodiment shown in FIG. 1C includes a power module substrate 1 and a heat sink 7a, and a semiconductor chip or the like is formed on the surface of the power module substrate 14 with a heat sink. The power module 14 is manufactured by mounting the electronic component 13.
The power module substrate 1 includes a ceramic substrate 2, a circuit layer 15 bonded to one surface of the ceramic substrate 2, and a metal layer 4 bonded to the other surface of the ceramic substrate 2. The electronic component 13 is soldered to the surface of the circuit layer 15 of the power module substrate 1, and the heat sink 7 a is brazed to the surface of the metal layer 4.

For the ceramic substrate 2, for example, nitride ceramics such as AlN (aluminum nitride) and Si ₃ N ₄ (silicon nitride), or oxide ceramics such as Al ₂ O ₃ (alumina) can be used. Moreover, the thickness of the ceramic substrate 11 can be set within a range of 0.2 to 1.5 mm.
The circuit layer 15 has a laminated structure of an aluminum layer 3 bonded to the surface of the ceramic substrate 2 and a copper layer 5 bonded on the aluminum layer 3. The aluminum layer 3 is made of aluminum having a purity of 99.99 mass% or more (so-called 4N aluminum), aluminum having a purity of 99 mass% or more (so-called 2N aluminum), or an aluminum alloy such as A1050 or A3003. The copper layer 5 is made of pure copper such as oxygen-free copper or tough pitch copper, or a copper alloy copper plate. These thicknesses are selected in the range of 0.1 mm to 3.0 mm for the aluminum layer 3 and 0.2 mm to 5.0 mm for the copper layer 5.
Similar to the aluminum layer 3 of the circuit layer 15, the metal layer 4 is aluminum having a purity of 99.99% by mass or more (so-called 4N aluminum), aluminum having a purity of 99% by mass or more (so-called 2N aluminum), or aluminum such as A1050 and A3003. An alloy aluminum plate is used. The thickness is selected in the range of 0.1 mm to 3.0 mm.
In the present embodiment, for example, the ceramic substrate 2 is Si ₃ N ₄ 0.32 mm, the aluminum layer 3 of the circuit layer 15 is 0.4 mm, the copper layer 5 is 2.0 mm, and the metal layer 4 is 0.4 mm thick. do it.

Moreover, as the heat sink 7a joined to this power module substrate 1, an aluminum alloy plate such as A3003, A6063, A5052 or the like can be used according to JIS standards with a purity of less than 99.0% by mass. Note that the heat sink has a suitable shape such as a flat plate, one in which a large number of pin-shaped fins are integrally formed by hot forging, etc., and one in which strip-like fins are formed in parallel by extrusion. Can be adopted.
In addition, the thickness of the heat sink 7a can be 0.4 mm-6.0 mm.
In this embodiment, a flat plate having a thickness of 1.0 mm made of A3003 is used as the heat sink 7a.

  Next, a method for manufacturing the power module substrate 14 with the heat sink configured as described above will be described. The power module substrate 14 with a heat sink is manufactured by bonding the ceramic substrate 2, the circuit layer 15, and the metal layer 4 (first bonding step), and then bonding the heat sink 7 a to the metal layer 4 (heat sink bonding step). Is done. Hereinafter, it demonstrates in order of this process.

(First joining process)
First, the aluminum layer 3 is laminated on one surface of the ceramic substrate 2 via the brazing material 16, and the copper layer 5 is laminated on the upper surface of the aluminum layer 3 via the titanium foil 22 as a diffusion preventing layer, The metal layer 4 is laminated on the other surface via the brazing material 16, and these are joined together. The brazing material 16 may be an Al—Si alloy or the like and used in the form of a foil. The thickness of the titanium foil 22 is set to 3 μm or more and 40 μm or less. In the present embodiment, the thickness is set to 10 μm.
Specifically, the ceramic substrate 2, the aluminum layer 3, and the metal layer 4 are laminated via a brazing material 16 as shown in FIG. 1A, and the copper layer 5 is placed on the upper surface of the aluminum layer 3 via a titanium foil 22. And the laminated body is pressed in the laminating direction using a pressurizing device 110 shown in FIG.
The pressure device 110 includes a base plate 111, guide posts 112 vertically attached to the four corners of the upper surface of the base plate 111, a fixed plate 113 fixed to the upper ends of the guide posts 112, and the base plates 111. A pressing plate 114 supported by a guide post 112 so as to freely move up and down between the fixing plate 113 and a spring provided between the fixing plate 113 and the pressing plate 114 to urge the pressing plate 114 downward. And urging means 115.
The fixed plate 113 and the pressing plate 114 are arranged in parallel to the base plate 111, and the above-described laminate S is arranged between the base plate 111 and the pressing plate 114. Cushion sheets 116 are disposed on both surfaces of the laminate S to make the pressure uniform. The cushion sheet 116 is set by a laminated plate of a carbon sheet and a graphite sheet. While being pressurized by the pressurizing device 110, the pressurizing device 110 and the pressurizing device 110 are placed in a heating furnace (not shown) and heated to a bonding temperature in a vacuum atmosphere to solder the aluminum layer 3 and the metal layer 4 onto the ceramic substrate 2. At the same time, the aluminum layer 3 and the titanium foil 22 and the copper layer 5 and the titanium foil 22 are solid phase diffusion bonded to form the power module substrate 1. The pressure The pressure for example 0.10MPa or more when 3.4MPa or less (1 kgf / cm ² or more 35 kgf / cm ² or less), the heating temperature is between 650 ° C. or less 610 ° C. or higher.

(Heat sink bonding process)
As shown in FIG. 1B, a heat sink 7 a is laminated on the metal layer 4 of the power module substrate 1 obtained by the first bonding process, as shown in FIG.
The clad material 6 has an Al—Si—Mg brazing material layer formed on both surfaces of a core material made of an aluminum alloy (A3003).
And these laminated bodies are pressurized (0.001 MPa-0.5 MPa) in the lamination direction using the pressurization apparatus 120 shown in FIG. 9, and are heated at 600 degreeC, for example. At this time, a cushion sheet 116 made of a carbon sheet 116a and a graphite sheet 116b is disposed on the surface of the copper layer 5 of the power module substrate 1, but a convex jig is disposed on the lower surface of the heat sink 7a via the carbon sheet 117. (Jig of the present invention) 8 is used. This convex jig 8 is a jig that presses the surface opposite to the bonding surface of the heat sink in accordance with the warp of the surface of the metal layer 4 of the power module substrate generated at the heat sink bonding temperature (600 ° C.), and is made of stainless steel. The pressing surface is formed in a convex shape.
As the carbon sheets 116a and 117, for example, G-347 manufactured by Asahi Graphite Co., Ltd. (thermal conductivity 116 W / mK, elastic modulus 10.8 GPa) can be used. The graphite sheet 116b is, for example, T-5 manufactured by Asahi Graphite Co., Ltd. (thermal conductivity 75.4 W / mK, elastic modulus 11.4 GPa) or graphite sheet PF manufactured by Toyo Carbon Industry Co., Ltd. (compression rate 47%, restoration rate 14). %) Or the like. Note that the carbon sheets 116a and 117 and the graphite sheet 116b used in the first bonding step can be the same.

The warp generated on the surface of the metal layer 4 of the power module substrate 1 is caused by a difference in thermal expansion coefficient between the copper layer 5 constituting the circuit layer 15 and the aluminum layer 3 and the metal layer 4 constituting the circuit layer 15. It is. FIG. 7 is a graph showing the result of measuring the change in the amount of warp due to the temperature change of the power module substrate 1 as will be described later, and the warp that causes the circuit layer 15 to have a concave shape occurs before the heat sink joining step. When heated at the time of heat sink bonding, the circuit layer 15 is warped in a convex shape at the heating temperature (600 ° C.).
Therefore, in a state where the convex jig 8 is pressurized, the pressurizing device 120 is placed in a heating furnace (not shown) and brazed by heating to a brazing temperature in a nitrogen atmosphere. At the time of brazing, the titanium foil 22 contained between the copper layer 5 and the aluminum layer 3 prevents the copper layer 5 and the aluminum layer 3 from diffusing.

  By joining the heat sink 7a to the power module substrate 1 in this way, the joint surface of the heat sink 7a is formed in a convex shape in accordance with the warp generated on the surface of the metal layer 4 of the power module substrate 1, so that the power module The substrate 1 and the heat sink 7a can be joined with almost no gap.

In addition, to supplement the description of the graph of FIG. 7, the power module substrate 1 used for the measurement has the same configuration as the first embodiment, and the thickness of the copper layer 5 of the circuit layer 15 is 2 mm. A 1.5 mm one was used.
The result of heating and measuring a copper layer 5 having a thickness of 2 mm from normal temperature to 300 ° C. is represented by a solid line (Cut 2 mm heating), and the measurement result after cooling from 300 ° C. to normal temperature is the same as the solid line (Cut 2 mm cooling) ).
The result of heating and measuring a copper layer 5 having a thickness of 1.5 mm from room temperature to 300 ° C. is represented by a solid line (Cut 1.5 mm heating), and the measurement result after cooling from 300 ° C. to room temperature is a solid line. (Cut 1.5 mm cooling). Moreover, the estimated value in the temperature of 300 degreeC or more assumed from these values is represented with the broken line.

  From the measurement results (including estimated values) of the warpage amount of the power module substrate 1 shown in this graph, the power module substrate 1 is concave on the copper layer 5 side at room temperature regardless of the thickness of the copper layer 5. Although it is warped in shape, the warpage is almost proportionally removed as it is heated, and the warpage disappears in the vicinity of 350 ° C to 400 ° C. On the contrary, when the temperature is exceeded, the copper layer 5 starts to warp in a convex shape. In the case of this example, the amount of substrate warpage around 600 ° C., which is the bonding temperature at the time of brazing (heat sink bonding process) of the heat sink 7a, is estimated to be −400 μm. The amount of substrate warpage when the bonding temperature in the heat sink bonding step) is about 500 ° C. is estimated to be −200 μm.

  The convex height H formed in the convex shape of the convex jig 8 used in the first embodiment is that of the substrate around 600 ° C., which is the bonding temperature in the above-described heat sink 7a brazing (heat sink bonding step). It is set in accordance with the estimated warpage amount (-400 μm in FIG. 7).

FIG. 3 shows the manufacturing method of the second embodiment in the order of steps. In this embodiment, the same reference numerals are given to the common elements as in the first embodiment of FIG. 1 (the same applies to the following embodiments).
In the power module substrate 21 of the second embodiment shown in FIG. 3B, the metal layer 20 has a laminated structure of an aluminum layer 19 and a copper layer 12 like the circuit layer 15. The heat sink 7a is bonded to the lower surface of the layer 12 in a state of being laminated in the thickness direction. The copper layer 12 is made of pure copper such as oxygen-free copper or tough pitch copper, or a copper plate of a copper alloy. The thickness of the copper layer 12 is selected in the range of more than 0.1 mm and 5.0 mm or less, for example, 1.0 mm. The aluminum layer 19 is made of aluminum having a purity of 99.99 mass% or more (so-called 4N aluminum), aluminum having a purity of 99 mass% or more (so-called 2N aluminum), or an aluminum alloy such as A1050 or A3003. The thickness of the aluminum layer 19 is selected in the range of 0.1 mm or more and 3.0 mm or less, for example, 0.4 mm.

In the method of manufacturing the power module substrate with a heat sink according to the second embodiment, first, in the first bonding step, the aluminum layer 3 is laminated on one surface of the ceramic substrate 2 via the brazing material 16, and further the aluminum layer 3 The copper layer 5 is laminated on the upper surface of the aluminum layer 19 via the titanium foil 22 as a diffusion preventing layer, the aluminum layer 19 is laminated on the other surface via the brazing material 16, and the titanium foil 22 is also applied to the lower surface of the aluminum layer 19. Then, the copper layer 12 is laminated, and these are joined together. As a result, the power module substrate 21 is manufactured.
In the heat sink joining step, the heat sink 7a is laminated on the copper layer 12 in the power module substrate 21 obtained in the first joining step, the carbon sheet 116a and the graphite sheet 116b are placed on the upper surface of the copper layer 5, and the carbon sheet 117 is placed on the lower surface of the heat sink 7a. Further, a convex jig 8 is arranged on the lower surface thereof, these are pressed in the laminating direction, and heated to a bonding temperature (400 ° C. to 548 ° C., 530 ° C. in the present embodiment) in a vacuum atmosphere to solid phase diffusion. Join.

  The convex height H formed in the convex shape of the convex jig 8 used in the second embodiment is such that the bonding temperature in the case of the above-described heat sink 7a solid phase diffusion bonding (heat sink bonding step) is around 500 ° C. Is set in accordance with the estimated substrate warpage amount (for example, −200 μm shown in FIG. 7).

In the power module substrate with a heat sink manufactured in this manner, the power module substrate 1 and the heat sink 7a can be joined with almost no gap, as in the first embodiment.
In the second embodiment, since the circuit layers 3 and 5 on one surface of the ceramic substrate 2 and the metal layers 19 and 12 on the other surface of the ceramic substrate 2 are asymmetric in configuration or thickness, warping is likely to occur. Is particularly effective.

FIG. 5 shows a third embodiment.
In the first embodiment and the second embodiment, the convex jig 8 shown in FIGS. 2 and 4 is used on the lower surface of the carbon sheet 117 in contact with the lower surface of the heat sink 7a. The shape of the heat sink 7b itself is formed into a convex shape. The convex shape has the same height H as the estimated warpage amount of the surface of the metal layer 4 of the power module substrate 1 when heated to the bonding temperature of the heat sink 7b. The heat sink 7b may be manufactured by casting or formed by cutting from a flat plate. On the other hand, the carbon sheet 117 in contact with the heat sink 7b is placed in a flat plate shape and brazed and joined in the same manner as the carbon sheet 116a in contact with the circuit layer 15.

  Also in this method for manufacturing a power module substrate with a heat sink, the bonding surface on the upper surface of the heat sink 7b is formed in a convex shape in accordance with the warp generated on the surface of the metal layer 4 of the power module substrate 1 at the bonding temperature of the heat sink 7b. The power module substrate 1 and the heat sink 7b can be joined with almost no gap.

FIG. 6 shows a fourth embodiment.
In the fourth embodiment, a convex carbon sheet 119 shown in FIG. 6 is used as a carbon sheet that comes into contact with the lower surface of the heat sink 7a when the heat sink 7a is joined, and flat stainless steel 118 is disposed on the lower surface. The convex shape has the same height H as the estimated warpage amount of the surface of the metal layer 4 of the power module substrate 1 when heated to the bonding temperature of the heat sink 7b.

  In the power module substrate with a heat sink manufactured as described above, the power module substrate 1 and the heat sink 7a can be joined with almost no gap, as in the first to third embodiments.

  The result of the confirmation experiment conducted for confirming the effect of the present invention will be described.

(Examples 1-3, Comparative Examples 1-3)
On one surface of a ceramic substrate (40 mm × 40 mm, thickness: 0.32 mm) made of Si ₃ N ₄ , an Al—Si brazing foil (thickness: 12 μm), an aluminum plate having a purity of 99% by mass or more (2N) ( 37 mm × 37 mm, thickness: 0.4 mm), titanium foil (thickness: 10 μm), copper plate made of oxygen-free copper (36 mm × 36 mm, thickness: in Examples 1, 3 and Comparative Examples 1-3, 2. 0 mm, 1.5 mm in Example 2), and an Al-Si brazing foil (thickness 12 μm), purity 99.99 mass% or more (4N) aluminum plate (37 mm) on the other surface of the ceramic substrate × 37 mm, thickness: 0.4 mm), heated at 645 ° C. while applying pressure of 1.0 MPa in the stacking direction, and a circuit board and a metal layer formed on a ceramic substrate. It was produced.
Clad material (core material: A3003 (0.25 mmt), brazing material layer (both sides): Al between the heat sink (50 mm × 60 mm, thickness: 1 mm) made of A3003 and the metal layer of the obtained power module substrate -Si-Mg alloy (0.025 mmt)) was interposed and joined. The bonding conditions were a nitrogen atmosphere, a bonding temperature of 600 ° C., and the bonding load as shown in Table 1. In addition, when joining the heat sink, the convex jig | tool (made from stainless steel) described in Table 1 was used, and the carbon sheet with a thickness of 1 mm was interposed between the heat sink and the convex jig. Further, in Comparative Example 1, a convex jig was not used, and a laminate of a 1 mm thick carbon sheet and a 1 mm thick graphite sheet was joined.
(Example 4)
Al-Si brazing foil (thickness 12 μm) on one surface (circuit layer side) of a ceramic substrate (40 mm × 40 mm, thickness: 0.32 mm) made of Si ₃ N ₄ , purity 99 mass% or more (2N ) Aluminum plate (37 mm × 37 mm, thickness: 0.4 mm), titanium foil (thickness: 10 μm), copper plate made of oxygen-free copper (36 mm × 36 mm, thickness: 2.0 mm) and ceramics Al—Si brazing foil (thickness 12 μm) on the other surface (metal layer side) of the substrate, aluminum plate (37 mm × 37 mm, thickness: 0.4 mm) with a purity of 99% by mass or more (2N), titanium foil (Thickness: 10 μm), a copper plate made of oxygen-free copper (36 mm × 36 mm, thickness: 1 mm) is laminated and heated at 645 ° C. while being pressurized at 1.0 MPa in the laminating direction. The power module substrate layer was formed was manufactured.
A heat sink made of A3003 (50 mm × 60 mm, thickness: 1 mm) and the metal layer (copper layer) of the obtained power module substrate were laminated so as to be in contact with the heat sink and solid phase diffusion bonded. The bonding conditions were as follows, in a vacuum atmosphere, at a bonding temperature of 530 ° C., and the bonding load as shown in Table 1. When joining the heat sink, a convex jig (made of stainless steel) described in Table 1 was used, and a carbon sheet having a thickness of 1 mm was interposed between the heat sink and the convex jig.

In addition, the board | substrate high temperature estimated curvature amount is calculated | required from the estimated value of the broken line of the graph of FIG.
The bonding rate was evaluated by using an ultrasonic image measuring machine to evaluate the bonded portion between the heat sink and the power module substrate. Calculate the bonding rate (%) = bonded good portion area / bonded surface area, and measure 5 pieces each. The average values obtained are shown in Table 1.

In Examples 1 to 4 of Table 1, the estimated warpage amount of the power module substrate and the height H of the convex portion formed in the convex shape of the convex jig are set to the same height, and the convex jig is pressed from the heat sink side. As a result, a good bonding rate is obtained.
The comparative example 1 is the result when pressing through a laminated sheet of a carbon sheet and a graphite sheet without using a convex jig, and has the lowest joining rate. Comparative Example 2 is a result when the height H of the convex portion formed in the convex shape of the convex jig is set lower than the estimated warpage amount of the power module substrate 1 and pressed from the lower surface on the heat sink side. Since the height H of the convex portion formed in the convex shape is insufficient, the effect is insufficient. In Comparative Example 3, the estimated warpage amount of the power module substrate and the convex portion height H formed in the convex shape of the convex jig are set to the same height, and the warpage of the substrate is corrected from the copper layer side which is the circuit layer. Thus, although it is a result of pressing in the reverse warp state with the convex jig, the joining rate could not be improved.
Since all of Comparative Examples 1 to 3 have a lower bonding rate than Examples 1 to 4, in the method for manufacturing a power module substrate with a heat sink of the present invention, the estimated warpage amount of the power module substrate and the convex jig It can be seen that a good bonding rate can be obtained by setting the height H of the convex portion formed in a convex shape to at least the same height and pressing the convex portion jig from the lower surface on the heat sink side.

  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.

DESCRIPTION OF SYMBOLS 1 ... Power module substrate 2 ... Ceramic substrate 3 ... Aluminum layer 4 ... Metal layer 5 ... Copper layer 6 ... Al clad material 7a ... Heat sink 7b ... Heat sink 8 ... Convex-shaped jig H ... Convex height 14 ... Power with heat sink Module substrate 110 ... Pressure device 116a ... Carbon sheet 116b ... Graphite sheet

Claims (4)

A circuit layer having a copper layer at least on the surface is bonded to one surface of the ceramic substrate, and a metal layer including an aluminum layer is bonded to the other surface of the ceramic substrate. A method of manufacturing a power module substrate with a heat sink by bonding a heat sink made of aluminum, wherein the circuit layer is pressed with a flat carbon sheet, and a bonding surface of the heat sink is generated at a heat sink bonding temperature. A method for manufacturing a power module substrate with a heat sink, characterized in that the power module substrate is formed in a convex shape and bonded to the warp of the metal layer surface of the power module substrate.   2. The method for manufacturing a power module substrate with a heat sink according to claim 1, wherein the heat sink is pressed against the metal layer by pressing a surface opposite to the bonding surface of the heat sink with a jig having the convex pressing surface. The method for manufacturing a power module substrate with a heat sink according to claim 1, wherein the bonding is performed.   2. The method for manufacturing a power module substrate with a heat sink according to claim 1, wherein a joint surface of the heat sink is formed in the convex shape in advance. Production method. A circuit layer having a copper layer at least on the surface is bonded to one surface of the ceramic substrate, and a metal layer including an aluminum layer is bonded to the other surface of the ceramic substrate. A device for pressurizing a laminate of the power module substrate and the heat sink in the laminating direction when joining the heat sink made of aluminum and manufacturing a power module substrate with a heat sink. there are, a flat carbon sheet for pressing the circuit layer, anda jig for pressing the heat sink, warpage of the metal layer surface of the substrate for the power module jig occurs at the heat sink junction temperature A pressurizing apparatus having a convex pressing surface adapted to the above .

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