JP2018116995A - Method for manufacturing power module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily manufacture a power module by suppressing the occurrence of warpage and joining a semiconductor device to a lead frame without causing a joining defect, damage and the like of the semiconductor device.SOLUTION: A method for manufacturing a power module is provided in which a power module substrate, a semiconductor device, and a lead frame are laminated with silver paste layers interposed between a circuit layer of the power module substrate and the semiconductor device and between the semiconductor device and the lead frame, respectively, thus the laminated material is obtained, then the laminated material is heated to a temperature equal to or higher than 180°C and equal to or lower than 350°C while pressure equal to or higher than 1 MPa and equal to or lower than 20 MPa is applied in the laminated direction, to sinter the silver paste layers to join between the circuit layer and the semiconductor device and between the semiconductor device and the lead frame.SELECTED DRAWING: Figure 1

Description

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

  In a power module used in a semiconductor device that controls a large current and a high voltage, it is connected to a semiconductor element, for example, as shown in Patent Document 1 in order to cope with a large current capacity and reduce wiring resistance. The wiring is formed by a lead frame made of copper, and a structure in which the junction between the semiconductor element and the lead frame is sealed with an epoxy resin or the like is employed.

  In addition, in this type of power module, for example, as shown in Patent Document 2, a circuit layer made of an aluminum plate or the like is bonded to one surface of a ceramic substrate including aluminum nitride, and the other surface. A power module substrate is used in which a heat dissipation layer made of an aluminum plate or the like is bonded. Further, a power module substrate with a heat sink is manufactured by bonding a heat sink made of copper or the like to the heat dissipation layer of the power module substrate.

  As a method of manufacturing a power module by bonding a semiconductor element and a lead frame to the power module substrate, for example, a semiconductor is formed on a circuit layer of a power module substrate in which a circuit layer and a heat dissipation layer are bonded to both surfaces of a ceramic substrate. After the elements are bonded by a method such as silver sintering or soldering, a lead frame made of copper is bonded onto the semiconductor element by soldering or the like.

JP 2001-291823 A Japanese Patent Laying-Open No. 2005-328087

  In the manufacturing method described above, after a semiconductor element is mounted, warping may occur because a semiconductor element having a small linear expansion coefficient is bonded to one side of the power module substrate. When this warpage occurs, for example, in a process of bonding a lead frame made of copper as shown in Patent Document 1 onto a semiconductor element, there is a possibility that a bonding failure or damage to the semiconductor element itself may occur.

  The present invention has been made in view of such circumstances, suppresses the occurrence of warpage, and joins a semiconductor element and a lead frame without causing poor bonding or damage to the semiconductor element, and thus a power module can be easily obtained. The purpose is to manufacture.

In the method for manufacturing a power module of the present invention, a semiconductor element is bonded to the circuit layer in the power module substrate in which a circuit layer made of aluminum or an aluminum alloy is bonded to one surface of the ceramic substrate. A power module manufacturing method in which a lead frame made of copper or a copper alloy is joined,
With the silver paste layer interposed between the circuit layer of the power module substrate and the semiconductor element and between the semiconductor element and the lead frame, the power module substrate, the semiconductor element, The lead frame is laminated, and the silver paste layer is sintered by heating the lead frame to a temperature of 180 ° C. or more and 350 ° C. or less in a state where a pressure of 1 MPa or more and 20 MPa or less is applied in the lamination direction, and the circuit A layer is bonded to the semiconductor element, and the semiconductor element is bonded to the lead frame.

In this manufacturing method, when the semiconductor element is mounted on the circuit layer of the power module substrate, the lead frames are also bonded together. For this reason, since the semiconductor element is bonded and pressed in a state of being sandwiched between the power module substrate and the lead frame, which are relatively rigid and difficult to deform, occurrence of warpage is suppressed. .
In this case, if the bonding material is solder, a liquid phase is generated by heating, so there is a risk that molten solder may flow out from between the members when pressed, so join without pressing. Therefore, it is difficult to join uniformly. In the case of joining using a silver paste layer, a liquid phase is not generated, and joining is performed by sintering. Therefore, sufficient pressurizing force can be applied, and the joining temperature is low, thus preventing warpage. It is valid.

  If the applied pressure is less than 1 MPa, bonding is not sufficient, and if it exceeds 20 MPa, the semiconductor element or the like may be damaged. If the heating temperature is less than 180 ° C., the silver paste layer cannot be sufficiently sintered, and if it exceeds 350 ° C., the semiconductor element may be destroyed. Since the circuit layer is made of aluminum or an aluminum alloy, it has a buffering action against the applied pressure, and a relatively large applied pressure of up to 20 MPa can be applied without damaging the semiconductor element.

  In the method for manufacturing a power module of the present invention, the power module substrate is bonded to a heat sink made of copper or a copper alloy on the side opposite to the circuit layer through a heat radiating layer made of aluminum or an aluminum alloy. It is good.

  Since this power module substrate is provided with a highly rigid heat sink on the side opposite to the semiconductor element and lead frame to be joined, the occurrence of warpage can be further suppressed.

  In the method for manufacturing a power module of the present invention, a spacer made of copper or a copper alloy is interposed between the circuit layer and the semiconductor element or between the semiconductor element and the lead frame via a silver paste layer. The spacers may be bonded together with the circuit layer, the semiconductor element, and the lead frame.

  The height position (position in the stacking direction) of the lead frame can be adjusted by the spacer, and the lead frame can be pulled out at an appropriate position. Further, since the spacer is bonded to the semiconductor element, there is also an effect of quickly dissipating the heat of the semiconductor element.

  According to the present invention, since the circuit layer, the semiconductor element, and the lead frame are bonded together, the problem of warpage can be solved, and bonding can be performed without causing bonding failure or damage to the semiconductor element. Can be laminated and bonded at a time, so that the manufacture is facilitated.

It is a flowchart which shows the manufacturing method of the power module which concerns on 1st Embodiment of this invention. It is sectional drawing which shows the process manufactured by the manufacturing method of 1st Embodiment in order of a process. It is sectional drawing of the power module manufactured with the manufacturing method of 1st Embodiment. It is an expanded sectional view explaining a base metal layer. It is sectional drawing of the power module manufactured by the manufacturing method of 2nd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1. First Embodiment <Overall Structure>
As shown in FIG. 2B, the power module substrate 10 used in the first embodiment includes a ceramic substrate 11 that is an insulating layer, a circuit layer 12 formed on one surface thereof, and a surface on the other surface. The formed heat dissipation layer 13 is provided. As shown in FIG. 3, a semiconductor element 30 is mounted on the surface of the circuit layer 12 of the power module substrate 10 via a spacer 20, a lead frame 40 is bonded to the semiconductor element 30, and the semiconductor element 30. The power module substrate 10 and the lead frame 40 are sealed with a mold resin 50 made of an epoxy resin or the like, whereby the power module 100 is configured.

The ceramic substrate 11 constituting the power module substrate 10 is made of, 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). It can be used, and the thickness is set in the range of 0.2 mm to 1.5 mm.

  The circuit layer 12 and the heat dissipation layer 13 are made of pure aluminum (so-called 2N aluminum) having a purity of 99.00% by mass or more, pure aluminum having a purity of 99.99% by mass or more (so-called 4N aluminum), or an aluminum alloy. The thickness is set to 0.1 mm to 5.0 mm, and it is usually formed in a planar rectangular shape smaller than the ceramic substrate 11. The circuit layer 12 and the heat dissipation layer 13 are joined to the ceramic substrate 11 with a brazing material such as an Al—Si, Al—Ge, Al—Cu, Al—Mg, or Al—Mn alloy. ing. The circuit layer 12 and the heat radiating layer 13 are bonded to the ceramic substrate 11 by punching into a desired outer shape by pressing, or after bonding a flat plate to the ceramic substrate 11, desired processing is performed by etching. It is formed in an outer shape or formed in a desired shape by any method.

The spacer 20 is formed of a block made of copper or copper alloy having conductivity, and is interposed between the circuit layer 12 and the semiconductor element 30 in order to adjust the distance between the circuit layer 12 and the semiconductor element 30. Connected to.
The semiconductor element 30 is an electronic component including a semiconductor, and an IGBT (Insulated Gate Bipolar Transistor), a MOSFET (Metal Oxide Semiconductor Field Transistor), a FWD (free Dhe) of FWD, etc. according to a required function. A semiconductor element is selected.
Such a semiconductor element 30 is provided with electrodes on the upper surface and the lower surface, and is electrically connected between the circuit layer 12 and the lead frame 40.

The lead frame 40 is formed in a strip shape made of copper alloy such as oxygen-free copper, pure copper such as tough pitch copper, or phosphor bronze, and has a thickness of 0.05 mm to 3.0 mm.
The spacer 20, the semiconductor element 30, and the lead frame 40 are bonded to the circuit layer 12 of the power module substrate 10 via a silver sintered bonding layer 71. In order to join with the silver sintered joining layer 71, a base metal layer 60 made of gold, silver, nickel or the like is formed on the joining surface of the circuit layer 12. Note that a base metal layer made of gold, silver, nickel, or the like may be formed on the planned bonding surfaces of the spacer 20, the semiconductor element 30, and the lead frame 40 by plating, sputtering, or the like. The mold resin 50 is made of an epoxy resin or the like, and except for the back surface of the heat dissipation layer 13 of the power module substrate 10, the side surfaces thereof, the ceramic substrate 11, the circuit layer 12, the spacer 20, the semiconductor element 30, and the semiconductor elements of the lead frame 40. The periphery of the connection portion to 30 is integrally sealed. The end portion of the lead frame 40 is pulled out from the mold resin 50.

<The manufacturing method of 1st Embodiment>
Next, a method for manufacturing the power module 100 configured as described above will be described. In this power module manufacturing method, as shown in FIG. 1, a power module substrate 10 is formed [power module substrate forming step], and a base metal layer 60 is formed on the planned bonding surface of the circuit layer 12 of the power module substrate 10. After forming [underlying metal layer forming step], the spacer 20, the semiconductor element 30, and the lead frame 40 are sequentially laminated on the circuit layer 12, and these are collectively bonded [collective bonding step], and then molded resin 50 is used as a resin. It is formed by sealing [resin sealing step]. Hereinafter, it demonstrates in order of a process.

[Power Module Substrate Formation Process]
As shown in FIG. 2 (a), an aluminum plate 12 'serving as the circuit layer 12 and an aluminum plate 13' serving as the heat radiation layer 13 are laminated on each surface of the ceramic substrate 11 with a brazing filler metal 15 interposed therebetween. The structure is heated in a state of being pressurized in the stacking direction, and the brazing material 15 is melted to join the aluminum plates 12 ′ and 13 ′ and the ceramic substrate 11, and the circuit layer 12 and the heat dissipation layer 13 are provided. The power module substrate 10 is formed (see FIG. 2B). Specifically, the laminated structure is put into a furnace while being pressurized and heated in a vacuum atmosphere at a temperature of 610 ° C. or higher and 650 ° C. or lower for 1 to 60 minutes.

[Base metal layer formation process]
Prior to the collective bonding, a base metal layer 60 made of gold, silver, nickel or the like is formed on the planned bonding surface of the circuit layer 12.
The base metal layer 15 can be obtained by forming gold, silver, nickel or the like into a thin film by plating or sputtering. The underlying metal layer 60 on the surface of the circuit layer 12 can also be formed by applying and baking a glass-containing silver paste.

(Formation method of base metal layer with glass-containing silver paste)
The method of forming the base metal layer 60 with the glass-containing silver paste on the surface of the circuit layer 12 will be described. The glass-containing silver paste includes a silver powder, a glass (lead-free glass) powder, a resin, a solvent, A dispersant, and the content of the powder component consisting of silver powder and glass powder is 60% by mass or more and 90% by mass or less of the entire glass-containing silver paste, and the balance is resin, solvent, dispersant Has been. The silver powder has a particle size of 0.05 μm or more and 1.0 μm or less, and for example, an average particle size of 0.8 μm is suitable. The glass powder has any one of bismuth oxide (Bi ₂ O ₃ ), zinc oxide (ZnO), boron oxide (B ₂ O ₃ ), lead oxide (PbO ₂ ), and phosphorus oxide (P ₂ O ₅ ) as a main component. The glass transition temperature is 300 ° C. or higher and 450 ° C. or lower, the softening temperature is 600 ° C. or lower, and the crystallization temperature is 450 ° C. or higher. For example, glass powder containing lead oxide, zinc oxide and boron oxide and having an average particle size of 0.5 μm is suitable.
The weight ratio A / G between the weight A of the silver powder and the weight G of the glass powder is adjusted within the range of 80/20 to 99/1, for example, A / G = 80/5.
A solvent having a boiling point of 200 ° C. or higher is suitable. For example, diethylene glycol dibutyl ether is used.
The resin is used to adjust the viscosity of the glass-containing silver paste, and those that decompose at 350 ° C. or higher are suitable. For example, ethyl cellulose is used.
In addition, a dicarboxylic acid-based dispersant is appropriately added. You may comprise a glass-containing silver paste, without adding a dispersing agent.

  This glass-containing silver paste is prepared by premixing a mixed powder obtained by mixing silver powder and glass powder and an organic mixture obtained by mixing a solvent and a resin together with a dispersant using a mixer, and the resulting premixed mixture is obtained using a roll mill. After mixing while kneading, the resulting kneaded product is produced by filtering with a paste filter. The viscosity of the glass-containing silver paste is adjusted to 10 Pa · s or more and 500 Pa · s or less, more preferably 50 Pa · s or more and 300 Pa · s or less.

When this glass-containing silver paste is applied to the bonding planned surface of the circuit layer 12 by a screen printing method or the like, and dried and baked at a temperature of 350 ° C. or more and 645 ° C. or less for 1 minute or more and 60 minutes or less, FIG. As shown, a base metal layer 60 having a two-layer structure of a glass layer 61 formed on the planned bonding surface side and a silver layer 62 formed on the glass layer 61 is formed. At this time, when the glass layer 61 is formed, the aluminum oxide film 12a naturally generated on the surface of the circuit layer 12 is melted and removed, and the glass layer 61 is directly formed on the circuit layer 12. A silver layer 62 is formed on the glass layer 61. When the glass layer 61 is firmly fixed to the circuit layer 12, the silver layer 62 is securely held and fixed on the circuit layer 12.
Although conductive particles (crystalline particles) 63 containing at least one of silver and aluminum are dispersed in the glass layer 61, it is presumed that the glass layer 61 has precipitated inside the glass layer 61 during firing. Also, fine glass particles 64 are dispersed inside the silver layer 62. The glass particles 64 are presumed to be agglomerated residual glass components in the process of firing the silver particles.

The average crystal grain size of the silver layer 62 in the base metal layer 60 formed in this way is adjusted within the range of 0.5 μm or more and 3.0 μm or less.
Here, when the heating temperature is less than 350 ° C. and the holding time at the heating temperature is less than 1 minute, the firing becomes insufficient and the base metal layer 60 may not be sufficiently formed. On the other hand, when the heating temperature exceeds 645 ° C. and when the holding time at the heating temperature exceeds 60 minutes, the firing proceeds too much and the average crystal grains of the silver layer 62 in the underlying metal layer 60 formed after the heat treatment There is a possibility that the diameter does not fall within the range of 0.5 μm to 3.0 μm.
In order to reliably form the base metal layer 60, the lower limit of the heating temperature during the heat treatment is preferably 400 ° C. or higher, and more preferably 450 ° C. or higher. Further, the holding time at the heating temperature is preferably 5 minutes or more, and more preferably 10 minutes or more.
On the other hand, in order to surely suppress the progress of firing, the heating temperature during the heat treatment is preferably 600 ° C. or lower, more preferably 575 ° C. or lower. Further, the holding time at the heating temperature is preferably 45 minutes or less, and more preferably 30 minutes or less.

(Silver paste layer)
These are laminated in a state where the silver paste layer 70 is interposed between the circuit layer 12 on which the base metal layer 60 is formed, the spacer 20, the semiconductor element 30, and the lead frame 40.
The silver paste layer 70 is a layer formed by applying a paste containing silver powder having a particle size of 0.05 μm to 100 μm, a resin, and a solvent.
As the resin used for the silver paste, ethyl cellulose or the like can be used. As a solvent used for the silver paste, α-terpineol or the like can be used.
The composition of the silver paste is such that the silver powder content is 60% by mass or more and 92% by mass or less of the entire silver paste, the resin content is 1% by mass or more and 10% by mass or less of the entire silver paste, and the balance is the solvent. Good.
In addition, the silver paste contains an organic metal compound powder such as carboxylic acid metal salt such as silver formate, silver acetate, silver propionate, silver benzoate, silver oxalate, etc. It can also be made. Moreover, 0 mass% or more and 10 mass% or less of reducing agents, such as alcohol and an organic acid, can also be contained with respect to the whole silver paste as needed.
The silver paste has a viscosity adjusted to 10 Pa · s to 100 Pa · s, more preferably 30 Pa · s to 80 Pa · s.
This silver paste is applied onto the base metal layer 60 of the circuit layer 12, the surface of the spacer 20, and the surface of the lead frame 40 by, for example, a screen printing method and the like, and dried to form the silver paste layer 70. The silver paste layer 70 only needs to be formed on any one of the surfaces to be bonded that face each other at the time of bonding. In the example shown in FIG. 2C, a silver paste layer 70 is formed on the surface of the circuit layer 12, the surface of the spacer 20 on the side facing the semiconductor element 30, and the surface of the lead frame 40 on the side facing the semiconductor element 30. Has been.

  As the silver paste layer 70, a silver oxide paste in which silver powder is replaced with silver oxide powder can also be used. The silver oxide paste contains silver oxide powder, a reducing agent, a resin, and a solvent, and in addition to these, contains an organometallic compound powder. The content of the silver oxide powder is 60% by mass or more and 92% by mass or less of the entire silver oxide paste, and the content of the reducing agent is 5% by mass or more and 15% by mass or less of the entire silver oxide paste. The content is 0% by mass or more and 10% by mass or less of the entire silver oxide paste, and the remainder is a solvent.

[Batch joining process]
As shown in FIG. 2C, the spacer 20 is overlaid on the silver paste layer 70 of the circuit layer 12, the semiconductor element 30 is overlaid on the silver paste layer 70 of the spacer 20, and the semiconductor element 30 is overlaid on the semiconductor element 30. The silver paste layers 70 of the lead frame 40 are stacked so as to be stacked.
And it heats to the temperature of 180 degreeC or more and 350 degrees C or less in the state which made the pressurization force of 1 MPa or more and 20 MPa or less act on the lamination direction. The holding time of the temperature should just be in the range of 1 minute or more and 60 minutes or less. By this heat treatment, the silver paste layer 70 is sintered to form a silver bonding layer 71 between the circuit layer 12, the spacer 20, the semiconductor element 30, and the lead frame 40, and the silver bonding layer 71 causes the circuit layer 12, The spacer 20, the semiconductor element 30, and the lead frame 40 are joined together.

  In addition, when the silver paste layer 70 which consists of a silver oxide paste containing a silver oxide and a reducing agent is used, the reduction silver particle which precipitates when a silver oxide reduces at the time of joining (baking), for example, is 10 nm-1 micrometer in particle size. Therefore, the dense silver bonding layer 71 can be formed and bonded more firmly.

[Resin sealing process]
After the spacer 20, the semiconductor element 30, and the lead frame 40 are joined to the power module substrate 10 as described above, the power module substrate 10, the spacer 20, and the semiconductor are removed except for the lower surface of the heat dissipation layer 13 of the power module substrate 10. The vicinity of the connection portion between the element 30 and the lead frame 40 is integrally sealed with a mold resin 50.
Specifically, the mold resin 50 is formed and sealed by a transfer molding method using a sealing material made of, for example, an epoxy resin or the like. The outer end portion of the lead frame 40 is exposed from the mold resin 50.

  The power module 100 manufactured in this manner is warped because the semiconductor element 30 is bonded and pressed in a state of being sandwiched between the power module substrate 10 having high rigidity and the lead frame 40. Therefore, it is possible to obtain a good bonding state without damaging the semiconductor element 30 and the like. In addition, the spacer 20, the semiconductor element 30, and the lead frame 40 can be bonded to the power module substrate 10 at a time, which facilitates manufacturing.

2. Second Embodiment FIG. 5 shows a second embodiment in which the power module substrate 10 includes a heat sink 80.
In the power module substrate 10 provided with the heat sink 80, the heat radiation layer 13 of the power module substrate 10 similar to that of the first embodiment is formed on pure copper such as oxygen-free copper or tough pitch copper, or copper such as Cu—Zr alloy. A heat sink 80 made of an alloy is joined.
The heat sink 80 includes a flat top plate portion 81 and a number of pin-like fins 82 that are integrally formed on one surface of the top plate portion 81. The thickness of the top plate portion 81 is set to 0.6 mm or more and 6.0 mm or less.
And the surface on the opposite side to the pin-shaped fin 82 of the top-plate part 81 of this heat sink 80 and the thermal radiation layer 13 are joined. The heat sink 80 and the heat dissipation layer 13 are bonded by diffusion bonding. This diffusion bonding is performed by applying a pressure of 0.3 MPa to 10 MPa in the laminating direction and heating to a temperature of 400 ° C. to 550 ° C.

Also in the case of the power module substrate 10 provided with the heat sink 80, as in the first embodiment, the silver paste layer 70 is interposed between the circuit layer 12, the spacer 20, the semiconductor element 30, and the lead frame 40. And heating them to a temperature of 180 ° C. or higher and 350 ° C. or lower with a holding time of 1 minute or longer and 60 minutes or shorter in a state where a pressing force of 1 MPa or higher and 20 MPa or lower is applied in the stacking direction. Join. Note that a base metal layer 60 made of gold, silver, nickel or the like is formed on the circuit layer 12 made of aluminum or an aluminum alloy before batch bonding. The spacer 20, the semiconductor element 30, and the lead frame 40 do not need to be provided with the base metal layer 60, but a base metal layer made of gold, silver, nickel, or the like may be formed on each planned bonding surface.
Then, after the collective joining, the power module 101 is manufactured by integrally sealing up to the top surface of the top plate portion 81 of the heat sink 80 with the mold resin 50.

In the case of the power module 101 including the heat sink 80, the rigidity of the heat sink 80 is high, so that the effect of preventing warpage is further increased.
In the example shown in FIG. 5, the heat sink 80 has a structure having pin-shaped fins 82 on the top plate portion 81. However, the heat sink 80 has a plate-shaped fin instead of the pin-shaped fins 82, and a plurality of cooling channels are provided via partition walls. It may be a multi-hole tubular member provided, a member provided with corrugated fins in one flat flow channel, or a member formed only of a flat plate-like top plate portion 81 having no fins.

In addition, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, although the spacer is provided in any of the embodiments, the spacer may not be provided when the position adjustment of the lead frame is unnecessary.

  Without providing a spacer, a semiconductor element and a lead frame joined together on the circuit layer of the power module substrate (Embodiment 1), a semiconductor element via a spacer on the circuit layer of the power module substrate, A lead frame joined together (Embodiment 2), and a semiconductor element and a lead frame joined together via a spacer on a circuit layer of a power module substrate having a heat sink (Embodiment 3) Three types were made.

  In either case, the power module substrate is made of aluminum nitride having a thickness of 0.635 mm as a ceramic substrate, aluminum having a purity of 99.99% as a circuit layer, oxygen-free copper having a thickness of 2.0 mm as a spacer, A silicon chip having a thickness of 0.15 mm was used as the semiconductor element, and an oxygen-free copper having a thickness of 1.0 mm was used as the lead frame. The base metal layer on the surface of the circuit layer was formed using the glass-containing silver paste described above, and after applying the silver paste as shown in FIG. A plurality of samples were prepared by changing the temperature at the time of bonding and the load at the time of bonding, and the presence or absence of bondability, member damage, or semiconductor element damage (element damage) was confirmed.

Bondability is obtained by using an ultrasonic image measuring machine manufactured by Insight Co., Ltd., when an ultrasonic flaw detection image of the bonding interface is obtained, and when the bonding rate is 90% or more, ○, when it is less than 90% It was.
The presence / absence of breakage of the member was determined by observing the degree of deformation of the circuit layer.
The presence or absence of damage to the semiconductor element is determined by using an ultrasonic image measuring machine manufactured by Insight Co., Ltd., when the probability that a crack is recognized in the semiconductor element is 10% or less, and the probability that a crack is recognized in the semiconductor element is 10%. When exceeding, it was set as x.
These results are shown in Table 1.

  As can be seen from Table 1, by joining at a temperature of 180 ° C. or higher and 350 ° C. or lower while applying a pressure of 1 MPa or more and 20 MPa or less, the bonding property is good, the member is damaged, or the semiconductor element is damaged. Could not be confirmed.

DESCRIPTION OF SYMBOLS 10 Power module substrate 11 Ceramic substrate 12 Circuit layer 13 Heat radiation layer 15 Brazing material 20 Spacer 30 Semiconductor element 40 Lead frame 50 Mold resin 60 Base metal layer 61 Glass layer 62 Silver layer 70 Silver paste layer 71 Silver bonding layer 80 Heat sink 100, 101 Power module

Claims (3)

A semiconductor element is bonded to the circuit layer of the power module substrate in which a circuit layer made of aluminum or an aluminum alloy is bonded to one surface of the ceramic substrate, and a lead frame made of copper or a copper alloy is bonded to the semiconductor element. A power module manufacturing method comprising:
With the silver paste layer interposed between the circuit layer of the power module substrate and the semiconductor element and between the semiconductor element and the lead frame, the power module substrate, the semiconductor element, The lead frame is laminated, and the silver paste layer is sintered by heating the lead frame to a temperature of 180 ° C. or more and 350 ° C. or less in a state where a pressure of 1 MPa or more and 20 MPa or less is applied in the lamination direction, and the circuit A method of manufacturing a power module, comprising bonding a layer and the semiconductor element, and joining the semiconductor element and the lead frame.   2. The power according to claim 1, wherein a heat sink made of copper or a copper alloy is joined to the power module substrate via a heat radiating layer made of aluminum or an aluminum alloy on the side opposite to the circuit layer. Module manufacturing method.   A spacer made of copper or a copper alloy is interposed between at least one of the circuit layer and the semiconductor element or between the semiconductor element and the lead frame via a silver paste layer, and the circuit layer and the semiconductor element The method for manufacturing a power module according to claim 1, wherein the spacer is simultaneously bonded together with the lead frame.

Images