TWI733011B - Manufacturing method of electronic component mounting module - Google Patents

Abstract

It has: a laminated body forming process, between the circuit layer of the insulated circuit substrate with the circuit layer and one side of the electronic component, the first silver glue layer composed of silver glue is formed, and the circuit layer is made of a ceramic substrate and It is composed of aluminum or aluminum alloy bonded to the ceramic substrate, and a second silver paste layer composed of silver paste is formed between the other side of the electronic component and the lead frame composed of copper or copper alloy to form These laminated bodies; and the integrated joining process. After the laminated body formation process, the laminated body is heated to 180°C or higher and 350°C or lower in a state in which a pressure of 1 MPa or more and 20 MPa or less is applied to the lamination direction. The heating temperature is used to sinter the first silver paste layer to form a first sintered silver bonding layer for sintering the first silver paste layer, and to sinter the second silver paste layer to form a second silver paste layer for sintering the second silver paste layer. The sintered silver bonding layer collectively bonds the circuit layer, electronic parts and lead frame.

Description

Manufacturing method of electronic component mounting module

The present invention relates to a method of manufacturing an electronic component mounting module in which power components, LED components, thermoelectric components, and other electronic components are mounted on an insulated circuit board.

Power modules used to control high-current, high-voltage semiconductor devices in electronic component mounting modules need to respond to large current capacity and reduce wiring resistance. Therefore, in Patent Document 1, for example, a structure is adopted: a lead frame made of copper is used to form wiring connected to a semiconductor element, and an epoxy resin or the like is used for electronic parts (power semiconductor elements). , Control semiconductor device) and lead frame (outer lead frame, inner lead frame) joint part is sealed with resin.

In addition, in electronic component mounting modules, for example, as shown in Patent Document 2, an insulated circuit substrate (a substrate for power module) is used. The insulated circuit substrate is bonded to one side of an insulating substrate such as aluminum nitride. There is a circuit layer composed of an aluminum plate or the like, and on the other side, a metal layer composed of an aluminum plate or the like is joined. A heat sink made of copper or the like is joined to the metal layer of the insulated circuit board.

As a method of manufacturing an electronic component mounting module by bonding electronic components and lead frames to the insulated circuit board, for example, by sintering silver bonding or soldering, the electronic components are bonded to the circuit layer of the insulated circuit board. In this insulated circuit board, a circuit layer and a metal layer are bonded to both sides of a ceramic substrate. After that, the lead frame made of copper is joined to the electronic component by welding or the like. Prior Art Documents Patent Documents

Patent Document 1: Japanese Patent Application Publication No. 2001-291823 　　 Patent Document 2: Japanese Patent Application Publication No. 2005-328087

Problems to be solved by the present invention

In the above-mentioned method of manufacturing an electronic component mounting module, after the electronic component is mounted, the electronic component with a small coefficient of linear expansion is bonded to one side of the insulated circuit board, and therefore, warpage may occur. Due to this warpage, in the process of bonding a lead frame made of copper to an electronic component as shown in Patent Document 1, for example, there is a possibility that poor bonding or damage to the electronic component itself may occur.

The present invention is a researcher in view of such circumstances, and its purpose is to suppress warpage, join electronic parts and lead frames without occurrence of poor bonding or damage to electronic parts, and to easily manufacture electronic parts and mounts. Module. Means to solve the problem

The manufacturing method of the power module of the present invention includes: a laminated body forming process, forming a first silver paste composed of silver paste between the circuit layer of the insulating circuit substrate with a circuit layer and one side of the electronic component The circuit layer is composed of a ceramic substrate and aluminum or aluminum alloy bonded to the ceramic substrate, and between the other side of the aforementioned electronic component and the lead frame composed of copper or copper alloy is formed of silver The second silver glue layer composed of glue to form these laminated bodies; and the overall joining process, after the aforementioned laminated body forming process, in a state where a pressure of 1 MPa or more and 20 MPa or less is applied to the lamination direction, The laminate is heated to a heating temperature of not less than 180°C and not more than 350°C, thereby sintering the first silver paste layer to form a first sintered silver bonding layer that sinters the first silver paste layer, and sintering the second The silver paste layer forms a second sintered silver bonding layer that sinters the second silver paste layer, and collectively bonds the circuit layer, the electronic component, and the lead frame.

In this manufacturing method, when the electronic component is mounted on the circuit layer of the insulated circuit board, the lead frame is also collectively bonded. The insulated circuit board with ceramic substrate and the lead frame made of copper or copper alloy have relatively high rigidity and are difficult to deform. Since the electronic components are joined and pressurized while being sandwiched between the insulated circuit board and the lead frame, the occurrence of warpage can be suppressed.

When the bonding material between the circuit layer and the electronic part and the bonding material between the electronic part and the lead frame is solder, the liquid phase is formed by heating. Therefore, when the pressure is applied to the lamination direction, there is a risk of molten solder from each member The fear of outflow between. Therefore, bonding is performed without pressing the laminate, and it is difficult to perform bonding uniformly. On the other hand, when the silver paste layer (the first silver paste layer and the second silver paste layer) is used, the bonding is performed by sintering without generating a liquid phase. Therefore, sufficient pressure can be applied to the stacking direction of the laminate. In addition, since the silver paste layer is lower than the sintering temperature (joining temperature), it is effective for preventing warpage.

When the pressure is less than 1 MPa, the bonding is insufficient, and when it exceeds 20 MPa, there is a risk of damaging the electronic components. When the heating temperature is less than 180°C, the silver glue layer cannot be fully sintered, and when it exceeds 350°C, there is a risk of damaging electronic parts. In addition, since the circuit layer is made of aluminum or aluminum alloy, it has a buffering effect on the pressing force, and a relatively large pressing force of up to 20 MPa can be used without damaging the electronic parts.

As a preferred embodiment of the method of manufacturing an electronic component mounting module of the present invention, the insulated circuit substrate has: a heat dissipation layer formed from a surface that is bonded to the ceramic substrate on the opposite side to the bonding surface of the circuit layer The heat sink is made of aluminum or aluminum alloy; and the heat sink is made of copper or copper alloy joined to the heat dissipation layer.

In the insulated circuit board, a high-rigidity heat sink made of copper or copper alloy is provided on the opposite side of the electronic component bonded to the circuit layer or the lead frame bonded to the electronic component. Therefore, the occurrence of warpage can be further suppressed.

As a preferred embodiment of the method of manufacturing the electronic component mounting module of the present invention, in the laminate forming process, a copper or copper alloy is further arranged between the first silver glue layer and the circuit layer. The third silver paste layer composed of silver paste is formed between the spacer and the aforementioned circuit layer. In the aforementioned general bonding process, the system can also be used to apply the aforementioned pressure to the laminate In the state of orientation, the laminate is heated to the heating temperature, thereby sintering the third silver paste layer to form a third sintered silver bonding layer that sinters the third silver paste layer, and simultaneously bonding the insulation circuit The substrate, the spacer, the electronic component, and the lead frame.

As a preferred embodiment of the method of manufacturing the electronic component mounting module of the present invention, in the laminate forming process, a copper or copper alloy is further arranged between the second silver glue layer and the lead frame. Formed spacer, and between the spacer and the lead frame, a third silver paste layer composed of silver paste is formed. In the general bonding process, the pressure may be applied to the lamination In the state of orientation, the laminate is heated to the heating temperature, thereby sintering the third silver paste layer to form a third sintered silver bonding layer that sinters the third silver paste layer, and simultaneously bonding the insulation circuit The substrate, the electronic component, the spacer, and the lead frame.

With spacers, the height position of the lead frame (position in the stacking direction) can be adjusted, and the lead frame can be pulled out at an appropriate position. In addition, since the spacer is joined to the electronic component, it also has the effect of rapidly diffusing the heat of the electronic component. Effect of invention

According to the present invention, since the circuit layers, electronic components, and lead frames of the insulated circuit board are collectively bonded, the problem of warpage of the electronic component mounting module can be eliminated, and bonding can be performed without occurrence of poor bonding or damage to the electronic components. . Moreover, since these layers can be laminated and joined at once, the manufacture of the electronic component mounting module becomes easy.

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

1. The first embodiment <Overall structure> 　　The first embodiment describes an example of applying an electronic component mounting module to the power module 100. The power module substrate (the insulated circuit substrate of the present invention) 10 used in the power module 100 is shown in FIG. 2B, and includes: an insulating layer, namely a ceramic substrate 11; and a circuit layer 12, formed on one side; And the heat dissipation layer 13 is formed on the other side. Furthermore, as shown in FIG. 3, on the surface of the circuit layer 12 of the power module substrate 10, a semiconductor element (electronic component of the present invention) 30 is mounted via a spacer 20, and a lead frame is bonded to the semiconductor element 30 40 to form a power module 100. Furthermore, the power module 100 is integrally sealed with the semiconductor element 30, the power module substrate 10, and the lead frame 40 by a stamper resin 50 made of epoxy resin or the like.

The ceramic substrate 11 constituting the power module substrate 10 is, for example _{, nitride-based ceramics such as AlN (aluminum nitride), Si 3} N ₄ (silicon nitride), or _{oxidation of Al 2} O ₃ (aluminum oxide). Material ceramics. The thickness of the ceramic substrate 11 is set in the range of 0.2 mm to 1.5 mm.

The circuit layer 12 and the heat dissipation layer 13 are formed of aluminum with a purity of 99.00% by mass or more (so-called 2N aluminum) or aluminum with a purity of 99.99% by mass or more (so-called 4N aluminum) or an aluminum alloy. The thickness of the circuit layer 12 and the heat dissipation layer 13 is, for example, set to a thickness of 0.1 mm to 5.0 mm. The circuit layer 12 and the heat dissipation layer 13 are generally formed into a rectangular shape having a smaller planar shape than the ceramic substrate 11. In addition, the circuit layer 12 and the heat dissipation layer 13 are joined to the ceramic substrate by soldering materials of Al-Si series, Al-Ge series, Al-Cu series, Al-Mg series, or Al-Mn series alloys. 11. In addition, the circuit layer 12 and the heat dissipation layer 13 are respectively formed into the desired shape by any one of the following methods: the ceramic substrate 11 is connected to the ceramic substrate 11 which is punched into a desired shape by a punching process, or After joining a flat plate to the ceramic substrate 11, it is formed into a desired shape by etching.

The spacer 20 is formed by a block made of copper or copper having conductivity. In order to adjust the interval between the circuit layer 12 and the semiconductor element 30, the spacer 20 is interposed between these and electrically connects these. In FIG. 3, two spacers 20 are connected to the circuit layer 12 side by side in the surface direction.

The semiconductor element 30 is an electronic component equipped with a semiconductor. For the semiconductor element 30, various semiconductor elements such as IGBT (Insulated Gate Bipolar Transistor), MOSFET (Metal Oxide Semiconductor Field Effect Transistor), and FWD (Free Wheeling Diode) are selected according to the required functions. In such a semiconductor element 30, electrodes are provided on the upper and lower surfaces, and the circuit layer 12 and the lead frame 40 are electrically connected. In FIG. 3, the semiconductor element 30 is joined to each of the two spacers 20, and the lead frame is provided in a state where the semiconductor elements 30 are connected to each other.

The lead frame 40 is made of copper or copper alloy. The lead frame 40 is formed in a strip shape made of, for example, oxygen-free copper, pure copper of refined copper, or a copper alloy such as phosphor bronze, and the thickness is set to be 0.05 mm or more and 3.0 mm or less. Furthermore, on the circuit layer 12 of the power module substrate 10, the spacer 20, the semiconductor element 30, and the lead frame 40 are bonded via the sintered silver bonding layers 711 to 713, respectively. As shown in FIG. 3, in this embodiment, the sintered silver bonding layer between the semiconductor element 30 and the spacer 20 among the sintered silver bonding layers 711 to 713 is used as the first sintered silver bonding layer 711. The sintered silver bonding layer connecting the semiconductor element 30 and the lead frame 40 is used as the second sintered silver bonding layer 712, and the sintered silver bonding layer between the bonding spacer 20 and the circuit layer 12 is used as the third sintered silver bonding layer 713. Separate the sintered silver bonding layers 711 to 713.

In addition, in order to bond the spacer 20 by the third sintered silver bonding layer 713, an underlying metal layer 60 made of gold (Au), silver (Ag), nickel (Ni), etc. is formed on the bonding surface of the circuit layer 12. In addition, although the illustration is omitted, it is also possible to form gold, silver, nickel, etc., on the planned bonding surface of each of the spacer 20, the semiconductor element 30, and the lead frame 40 by plating or sputtering. Base metal layer.

The stamper resin 50 is made of epoxy resin or the like. The mold resin 50 integrally seals the side surface of the heat dissipation layer 13, the ceramic substrate 11, the circuit layer 12, the spacer 20, the semiconductor element 30, and the lead frame 40, except for the back surface of the heat dissipation layer 13 of the power module substrate 10 The periphery of the connection part of the semiconductor element 30. The end of the lead frame 40 is led out from the mold resin 50 to the outside.

<The manufacturing method of the first embodiment> 　　 Next, a method of manufacturing the power module 100 configured as described above will be described. The power module manufacturing method is as shown in FIG. 1, forming a power module substrate 10 [power module substrate formation process], and forming a base on the bonding plan surface of the circuit layer 12 of the power module substrate 10 Metal layer 60 [underlying metal layer formation process]. Thereafter, a laminate in which the spacer 20, the semiconductor element 30, and the lead frame 40 are sequentially laminated is formed on the circuit layer 12 [Laminate Formation Process], and these laminates are collectively bonded [Integrated Bonding Process ] Then, resin sealing [resin sealing process] is performed by the press-molded resin 50 to form it. Hereinafter, the description will be made in the order of processes.

[Power module substrate formation process] 　　As shown in FIG. 2A, on each surface of the ceramic substrate 11, an aluminum plate 12' as a circuit layer 12 and an aluminum plate 13' as a heat dissipation layer 13 are laminated via a solder 15. In the state of being pressed to the lamination direction, these laminated structures are heated to melt the solder 15 to thereby join the respective aluminum plates 12', 13' and the ceramic substrate 11 to form a circuit The power module substrate 10 of the layer 12 and the heat dissipation layer 13 (see FIG. 2B). Specifically, it is placed in a furnace in the state of a pressurized laminated structure, and heated in a vacuum atmosphere at a temperature of 610° C. or more and 650° C. or less for 1 minute to 60 minutes.

[Underlying metal layer formation process] 　　Before the layered body forming process, the underlying metal layer 60 made of gold, silver, nickel, etc. is formed on the surface of the circuit layer 12 to be joined. The base metal layer 15 can be obtained by plating or sputtering gold, silver, nickel, etc., into a thin film. In addition, the base metal layer 60 on the surface of the circuit layer 12 can also be formed by coating and firing a silver paste containing glass.

(Method of forming base metal layer by silver paste containing glass) The method of forming the base metal layer 60 on the surface of the circuit layer 12 by using a silver paste containing glass will be described. The silver glue containing glass is composed of silver powder, glass (lead-free glass) powder, resin, solvent and dispersant. The content of the powder composed of silver powder and glass powder is set as the whole silver glue containing glass 60% by mass or more and 90% by mass or less, and the remainder is set as resin, solvent, and dispersant. The particle size of the silver powder is set to 0.05 μm or more and 1.0 μm or less, for example, the average particle diameter is 0.8 μm. Glass powder, as the main component, is set to contain bismuth oxide (Bi ₂ O ₃ ), zinc oxide (ZnO), boron oxide (B ₂ O ₃ ), lead oxide (PbO ₂ ), phosphorus oxide (P ₂ O ₅₎ For any one or two or more types of ), the glass transition temperature is set to 300°C or higher and 450°C or lower, the softening temperature is set to 600°C or lower, and the crystallization temperature is set to 450°C or higher. For example, glass powder containing lead oxide, zinc oxide, and boron oxide and having an average particle diameter of 0.5 μm is preferable.

In addition, the weight ratio A/G of the weight A of the silver powder to the weight G of the glass powder is adjusted to a range of 80/20~99/1, for example, A/G=80/5. The solvent preferably has a boiling point of 200°C or higher. For example, diethylene glycol dibutyl ether can be used. The resin is the one that adjusts the viscosity of the silver glue containing glass, and it is better to be decomposed above 350°C. For example, ethyl cellulose can be used. In addition, a dicarboxylic acid-based dispersant can be appropriately added. It is also possible to form a silver paste containing glass without adding a dispersant.

The glass-containing silver paste is manufactured by the following method: "Mixed powder mixed with silver powder and glass powder" and "Organic mixture mixed with solvent and resin" are mixed with a dispersant by a mixer Preliminary mixing is performed together, and the obtained preliminary mixture is kneaded by a rolling mill on one side, and after mixing on the other side, the obtained kneaded material is filtered by an electro-paste filter. The glass-containing silver glue has its viscosity adjusted to 10Pa･s or more and 500Pa･s or less, more preferably 50Pa･s or more and 300Pa･s or less.

This glass-containing silver paste is applied to the bonding surface of the circuit layer 12 by screen printing or the like, and after drying, it is fired at a temperature of 350°C or higher and 645°C or lower for 1 minute or more and 60 minutes or less time. As a result, as shown in FIG. 4, a base metal layer 60 having a two-layer structure of a glass layer 61 and a silver layer 62 is formed. The glass layer 61 is formed on the side where the bonding is planned, and the silver layer 62 is formed On the glass layer 61. 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, so that the glass layer 61 is directly formed on the circuit layer 12, and the silver layer 62 is formed on the glass layer 61. By the way that the glass layer 61 is firmly fixed to the circuit layer 12, the silver layer 62 is surely held and fixed on the circuit layer 12.

In the glass layer 61, conductive particles (crystalline particles) 63 containing at least one of silver or aluminum are dispersed. The conductive particles 63 are inferred to be precipitated inside the glass layer 61 at the time of firing. In addition, within the silver layer 62, fine glass particles 64 are also dispersed. The glass particles 64 are estimated to be those that aggregate the remaining glass components during the firing of 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 to be in 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 heating temperature retention time is less than 1 minute, the firing becomes insufficient, and the underlying metal layer 60 may not be sufficiently formed. On the other hand, when the heating temperature exceeds 645°C and the heating temperature retention time exceeds 60 minutes, the firing will proceed excessively, and the silver layer 62 in the base metal layer 60 formed after the heat treatment may be averaged There is a possibility that the crystal grain size cannot be within the range of 0.5 μm or more and 3.0 μm or less.

In addition, in order to surely 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. In addition, the holding time of the heating temperature is preferably set to 5 minutes or more, and more preferably set to 10 minutes. On the other hand, in order to surely suppress the progress of firing, it is preferable to set the heating temperature during the heat treatment to 600°C or lower, and more preferably to set it to 575°C or lower. Moreover, it is preferable to set the holding time of the heating temperature to 45 minutes or less, and it is more preferable to set it to 30 minutes or less.

[Laminated body formation process] After the 　　 base metal layer formation process, 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, a silver paste layer made of silver paste is formed 701~703, and form a layered body with these layers. As shown in FIG. 2C, among the silver glue layers 701 to 703, the silver glue layer formed between the semiconductor element 30 and the spacer 20 is used as the first silver glue layer 701 to be formed on the semiconductor element 30 and the lead The silver glue layer between the frames 40 serves as the second silver glue layer 702, and the silver glue layer formed between the spacer 20 and the circuit layer 12 serves as the third silver glue layer 703 to distinguish the silver glue layers 701 to 703 .

The silver glue layers 701 to 703 are layers formed by coating silver glue, and the silver glue is formed by containing silver powder with a particle diameter of 0.05 μm-100 μm, resin, and solvent. As the resin used for the silver glue, ethyl cellulose or the like can be used. As the solvent used for the silver glue, α-terpineol and the like can be used. As the composition of the silver glue, the content of silver powder can also be made 60% by mass to 92% by mass of the whole silver glue, and the content of the resin can be made 1% by mass to 10% by mass of the whole silver glue, so that the residual Part of it becomes a solvent.

In addition, in the silver paste, organic metal compound powders such as silver formate, silver acetate, silver propionate, silver benzoate, silver oxalate, and other carboxylic acid metal salts may contain 0% by mass or more of the entire silver paste. Less than mass%. In addition, if necessary, a reducing agent such as an alcohol or an organic acid may be contained from 0% by mass to 10% by mass relative to the entire silver paste. In addition, the viscosity of the silver paste is adjusted to 10 Pa･s or more and 100 Pa･s or less, more preferably 30 Pa･s or more and 80 Pa･s or less.

For example, as shown in FIG. 2C, the silver paste is respectively coated on 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 screen printing, etc., and then dried. Thus, silver glue layers 701 to 703 are formed. The silver glue layers 701 to 703 only need to be formed on any surface of the opposing bonding plan surfaces during bonding. In the example shown in FIG. 2C, silver 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, respectively. Adhesive layer 701~703.

In addition, as the silver paste layers 701 to 703, silver paste in which silver powder is used instead of silver oxide powder may also be used. The silver paste contains silver oxide powder, reducing agent, resin and solvent, and, in addition to these, contains organometallic compound powder. The content of silver oxide powder is set to 60% by mass to 92% by mass of the entire silver paste, the content of reducing agent is set to 5% to 15% by mass of the entire silver paste, and the content of organic metal compound powder It is set to be 0 mass% or more and 10 mass% or less of the entire silver paste, and the remaining part is set as a solvent.

2C, the spacer 20 is overlapped on the third silver paste layer 703 of the circuit layer 12, and the semiconductor element 30 is overlapped on the first silver paste layer 701 of the spacer 20, and the lead frame The second silver glue layer 702 of 40 is superimposed on the semiconductor element 30, and these are placed in a laminated state to form a laminated body.

[Overall joining process] 　　 After the layered body formation process, the layered body is heated to a heating 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 to the layering direction. The holding time of the heating temperature may be within the range of 1 minute or more and 60 minutes or less. By this heat treatment, the silver paste layers 701 to 703 are sintered, and sintered silver bonding layers 711 to 713 are formed among the circuit layer 12, the spacer 20, the semiconductor element 30, and the lead frame 40. In detail, the first silver paste layer 701 is sintered to form the first sintered silver bonding layer 711 that sinters the first silver paste layer 701, and the second silver paste layer 702 is sintered to form the second silver paste layer 702. The second sintered silver bonding layer 712. In addition, the third silver paste layer 703 is sintered to form a third sintered silver bonding layer 713 for sintering the third silver paste layer 703. Furthermore, by these sintered silver bonding layers 711 to 713, the circuit layer 12, the spacer 20, the semiconductor element 30, and the lead frame 40 are collectively and simultaneously bonded.

In addition, when the silver paste layers 701 to 703 composed of silver paste containing silver oxide and a reducing agent are used, the reduced silver particles precipitated by the reduction of silver oxide will become very unusual during bonding (sintering). Fine, for example, the particle size is 10 nm to 1 μm. Therefore, dense sintered silver bonding layers 711 to 713 can be formed to bond the circuit layer 12, the spacer 20, the semiconductor element 30, and the lead frame 40 more firmly.

[Resin Encapsulation Process] 　　 As described above, after the spacer 20, the semiconductor element 30, and the lead frame 40 are bonded to the power module substrate 10, except for the underside of the heat dissipation layer 13 of the power module substrate 10, press The mold resin 50 integrally seals the vicinity of the connection portion of the power module substrate 10, the spacer 20, the semiconductor element 30, and the lead frame 40. Specifically, for example, a sealing material made of epoxy resin or the like is used to form and seal the stamper resin 50 by a transfer molding method. The outer end of the lead frame 40 is exposed from the mold resin 50.

In the power module 100 manufactured in this way, the semiconductor element 30 is bonded and pressurized while being sandwiched between the highly rigid power module substrate 10 and the lead frame 40. Therefore, warpage can be suppressed. The production. Therefore, the semiconductor element 30 is not damaged, and the semiconductor element 30, the power module substrate 10, the spacer 20, and the lead frame 40 can be bonded in a good state. 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, and manufacturing becomes easy.

2. The second embodiment "Figure 5" shows the power module 101 of the second embodiment. In the power module 101 of the second embodiment, a heat sink 80 is provided on the power module substrate 10. The power module substrate 10 provided with the heat sink 80 refers to a heat sink 80 made of copper or copper alloy bonded to the heat sink layer 13 of the power module substrate 10 that is the same as the first embodiment. The heat sink 80 is made of, for example, pure copper such as oxygen-free copper or refined copper, or a copper alloy such as Cu-Zr alloy.

The radiating fin 80 has a flat top plate portion 81 and a plurality of pin-shaped radiating fins 82 integrally protruding and formed on one surface of the top plate portion 81. The thickness of the top plate 81 is set to be 0.6 mm or more and 6.0 mm or less. Then, the surface on the opposite side of the pin-shaped heat sink 82 of the top plate portion 81 of the heat sink 80 and the heat sink layer 13 are joined. The heat dissipation fins 80 and the heat dissipation layer 13 are bonded by diffusion bonding. In this diffusion bonding, it is performed by applying a pressure of 0.3 MPa or more and 10 MPa or less in the lamination direction, and heating to a temperature of 400° C. or more and 550° C. or less.

Although not shown in the case of the power module substrate 10 provided with the heat sink 80, similar to the first embodiment, silver is formed between the circuit layer 12, the spacer 20, the semiconductor element 30, and the lead frame 40. The adhesive layers 701 to 703 are laminated to form a laminate [Laminate Formation Process]. In addition, in a state where a pressure of 1 MPa or more and 20 MPa or less is applied to the stacking direction of the laminates, heating to a temperature of 180°C or more and 350°C or less for a holding time of 1 minute or more and 60 minutes or less can be used in a comprehensive manner. Join these [overall joining works].

In addition, in the circuit layer 12 made of aluminum or aluminum alloy, a base metal layer 60 made of gold, silver, nickel, or the like is formed before the collective bonding. Although the spacer 20, the semiconductor element 30, and the lead frame 40 do not need to be provided with the base metal layer 60, a base metal layer composed of gold, silver, nickel, etc. may be formed on the respective bonding surfaces. "Furthermore, after the overall bonding process, the molding resin 50 is used to integrally seal to the upper surface of the top plate 81 of the heat sink 80 [resin encapsulation process], thereby manufacturing the power module 101 shown in FIG. 5.

In the case of the power module 101 provided with the heat sink 80, since the heat sink 80 has high rigidity, the effect of preventing warpage becomes higher.

In the example shown in FIG. 5, although the heat sink 80 is configured to have a pin-shaped heat sink 82 on the top plate portion 81, it may also be provided with a plate-shaped heat sink, and a plurality of heat sinks may be provided through the partition wall. Instead of pin-shaped fins 82, the cooling channel has a porous tube shape, a flat channel with corrugated fins, or only a flat top plate 81 without fins, etc. .

In addition, the present invention is not limited to the above-mentioned embodiment, and various changes can be made without departing from the scope of the main content of the invention.

For example, even in any embodiment, although the spacer 20 is also provided, it is not necessary to provide the spacer when the position of the lead frame 40 does not need to be adjusted.

In addition, even in any embodiment, although the spacer 20 is arranged between the first silver glue layer 701 and the circuit layer 12, the spacer 20 may also be arranged on the second silver glue layer 702 and the lead frame 40. between. In this case, in the laminate forming process, the third silver paste layer 703 is formed on the spacer 20 and the lead frame 40. As a result, the third silver paste layer 703 can be sintered to form the third sintered silver bonding layer that sinters the third silver paste layer 703 in the integrated bonding process, and the power module substrate 10, the semiconductor element 30, and the semiconductor element 30 can be bonded at the same time. The spacer 20 and the lead frame 40. Example

Three types of power modules were produced as follows: "A power module in which a semiconductor element and a lead frame are collectively bonded to the circuit layer of a power module substrate without spacers (Embodiment 1)", "Across the gap This is a power module in which a semiconductor element and a lead frame are collectively bonded to the circuit layer of a power module substrate (Embodiment 2)", "the semiconductor element and lead frame are collectively bonded via spacers to a power module equipped with a heat sink The power module on the circuit layer of the substrate for the power module of the chip (Embodiment 3)".

In either case, the power module substrate uses aluminum nitride with a thickness of 0.635mm as the ceramic substrate, aluminum with a thickness of 0.4mm and a purity of 99.99% as the circuit layer, and oxygen-free copper with a thickness of 2.0mm as the spacer. A silicon wafer with a thickness of 0.15 mm is used as a semiconductor element, and an oxygen-free copper with a thickness of 1.0 mm is used as a lead frame.

The base metal layer on the surface of the circuit layer is formed by using the above-mentioned silver paste containing glass. As shown in FIG. 2C, after coating the silver paste, it is laminated to form an overall bonding. Change the heating temperature during bonding and the pressure applied during bonding to prepare a plurality of samples, and confirm whether there are bonding properties, damage to the components, and damage to the semiconductor element (damage of the element).

The bonding property is obtained by using the ultrasonic imaging diagnostic device manufactured by Insight to obtain the ultrasonic flaw detection image of the bonding interface. When the bonding rate is more than 90%, it is set to "good", and when the bonding rate is less than 90%, it is set to "good". Become "bad".

Whether there is damage to the component, observe the degree of deformation of the circuit layer, and set the normal condition as "good", and the situation with crushing at the end as "bad".

Whether there is damage to the semiconductor device, the ultrasonic imaging diagnostic device manufactured by Insight is used, and the probability of seeing a crack in the semiconductor device is set as "good", and the probability of seeing a crack in the semiconductor device is more than 10%. 10% of cases are set as "bad".

These results are shown in Table 1.

It can be seen from the table 1 that by applying a pressure of 1 MPa to 20 MPa, and a heating temperature of 180°C to 350°C for all-in-one bonding, it is impossible to determine whether the bonding is good and the components are damaged or the semiconductor device is completely bonded. The damage. Industrial availability

Since the circuit layer and the lead frame of the semiconductor element are collectively bonded, the problem of warpage can be eliminated without the occurrence of poor bonding or damage to electronic parts, etc., and the bonding can be carried out at a time by stacking these layers. Therefore, the electronic The manufacturing of the component mounting module has also become easier.

10‧‧‧Power module substrate (insulated circuit substrate) 11‧‧‧Ceramic substrate 12‧‧‧Circuit layer 13‧‧‧Heat dissipation layer 15‧‧‧Solder 20‧‧‧Spacer 30‧‧‧Semiconductor element (Electronic parts) 40‧‧‧Lead frame 50‧‧‧Compression molding resin 60‧‧‧Base metal layer 61‧‧‧Glass layer 62‧‧‧Silver layer 701‧‧‧First silver glue layer 702‧‧‧ 2Silver glue layer 703‧‧‧The third silver glue layer 711‧‧‧The first sintered silver bonding layer 712‧‧The second sintered silver bonding layer 713‧‧ The third sintered silver bonding layer 80‧‧‧The heat sink 100 , 101‧‧‧Power module (electronic parts installation module)

[Fig. 1] A flowchart showing the manufacturing method of the power module according to the first embodiment of the present invention.　　 [FIG. 2A] A cross-sectional view explaining the power module substrate forming process in the manufacturing method of the first embodiment.　　[Figure 2B] A cross-sectional view of a power module substrate.　　[Figure 2C] A cross-sectional view illustrating the integrated joining project.　　 [Fig. 3] A cross-sectional view of the power module manufactured by the manufacturing method of the first embodiment.　　 [Figure 4] An enlarged cross-sectional view of the base metal layer is illustrated.　　 [FIG. 5] A cross-sectional view of a power module manufactured by the manufacturing method of the second embodiment of the present invention.

Claims (4)

A method of manufacturing an electronic component mounting module includes: 　　 layered body forming process, forming a first silver paste composed of silver paste between the circuit layer of an insulating circuit substrate with a circuit layer and one side of the electronic part The circuit layer is composed of a ceramic substrate and aluminum or aluminum alloy bonded to the ceramic substrate, and between the other side of the aforementioned electronic component and the lead frame composed of copper or copper alloy is formed of silver The second silver glue layer composed of glue to form these laminated bodies; and the overall joining process, after the aforementioned laminated body forming process, in a state where a pressure of 1 MPa or more and 20 MPa or less is applied to the lamination direction, The laminate is heated to a heating temperature of not less than 180°C and not more than 350°C, thereby sintering the first silver paste layer to form a first sintered silver bonding layer that sinters the first silver paste layer, and sintering the second The silver paste layer forms a second sintered silver bonding layer that sinters the second silver paste layer, and collectively bonds the circuit layer, the electronic component, and the lead frame. For example, the method for manufacturing an electronic component mounting module in the scope of the patent application, wherein the 　　 said insulated circuit board has: 　　 heat dissipation layer, which is bonded to the surface of the ceramic board on the opposite side to the bonding surface of the circuit layer The heat sink is made of aluminum or aluminum alloy; and the heat sink is made of copper or copper alloy joined to the heat dissipation layer. For example, the method for manufacturing an electronic component mounting module in the scope of the patent application, in which 　　 is further arranged between the first silver glue layer and the circuit layer in the above-mentioned layered body formation process by copper or copper alloy And between the spacer and the aforementioned circuit layer, a third silver glue layer composed of silver glue is formed. 　　 In the aforementioned general bonding process, the pressure is applied to the lamination direction. In the state, the laminate is heated to the heating temperature, thereby sintering the third silver paste layer to form a third sintered silver bonding layer that sinters the third silver paste layer, and simultaneously bonding the insulating circuit board, The spacer, the electronic component, and the lead frame. For example, the method for manufacturing an electronic component mounting module in the scope of the patent application, wherein 　　 is further arranged between the second silver glue layer and the lead frame in the above-mentioned layered body formation process by copper or copper alloy And the third silver paste layer composed of silver paste is formed between the spacer and the aforementioned lead frame. 　　 In the above-mentioned integrated bonding process, the pressure is applied to the lamination direction. In the state, the laminate is heated to the heating temperature, thereby sintering the third silver paste layer to form a third sintered silver bonding layer that sinters the third silver paste layer, and simultaneously bonding the insulating circuit board, The electronic component, the spacer, and the lead frame.

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