JPH04196345A - Structure of metal substrate - Google Patents

Abstract

PURPOSE:To contrive to improve the reliability of the structure of a metal base by a method wherein first and second metal bases are made to bond to each other in the direction vertical to the direction in which an insulating layer and a wiring layer are formed. CONSTITUTION:First and second base metal films 9 are formed into a constitution, wherein they are bonded to each other in the direction vertical to a direction, in which an insulating layer 3 and a wiring layer 4 are laminated. Accordingly, as heat generated from an electronic component generating much heat is dissipated in the air via the metal films 9 of a high heat conductivity, the heat is not accumulated at the junction part between a metal board 1 and the electronic component generating much heat. As a result, a temperature rise is not caused and a breakdown of a semiconductor element 5, which is caused by overheating, is prevented. Moreover, as the electronic component 5 generating a little heat is mounted on the metal film 9, which has little thermal expansion due to a temperature difference in the outside environment, the thermal expansion of the metal base 9 is a little and the stress can be lessened. As a result, the separation of the component 5 generating heat a little from the metal films 9 due to the thermal expansion is prevented. Thereby, the reliability of a structure consisting of the substrate 1 and the electronic component 10 can be improved.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to the structure of a metal substrate.

(Prior Art) A conventional metal substrate has a structure as shown in FIG. This metal substrate 1 has a general metal substrate structure in which wiring I4 is laminated on aluminum 2, which is a base metal 9, with an insulating layer interposed therebetween.

Mounted on the wiring layer 4 are a semiconductor element (power device) 6 which is an electronic component and which generates a large amount of heat, and a semiconductor element 5 which generates a small amount of heat.

The semiconductor element 5, which generates a small amount of heat, is electrically connected to the wiring layer 4 by a wire 7 made of aluminum 2, and the bonding portion between the wire 7 and the wiring layer 4 is connected by ultra-high wave bonding. The power device 6 is electrically connected to the wiring layer 4 through a terminal 15, and the joint between the terminal 15 and the wiring layer 4 is connected through a solder 8.

[Problem to be solved by the invention]

However, in such a conventional metal substrate structure, when the base metal 9 is made of aluminum 2,
Due to heat generated by the power device 6 and temperature changes due to temperature differences in the external environment, heat is generated at the junction between the aluminum 2 and the semiconductor element 5, which generates less heat, and the coefficient of thermal expansion between the aluminum 2 and the semiconductor element 5, which generates less heat, increases. Because of the large difference between the two, the heat generated by the power device 6 may cause the bond between the semiconductor element 5 and the metal substrate 1 to separate.

Therefore, especially when the S1 chip, which is a semiconductor element with a large chip size and low heat generation, is mounted, a stress-reducing material (buffer material) is used between the metal substrate and the 81 chip.
Although a method has been taken to reduce the stress by inserting an S1 chip, this increases the number of parts and man-hours, and even then, separation of the joint between the S1 chip and the metal substrate still occurs.

In addition, when the base metal is an iron-based alloy, the thermal expansion coefficient of the iron-based alloy is small, making it possible to bond Si chips and chip components to the iron-based alloy, but heat dissipation is caused by the low thermal conductivity of the iron-based alloy. When electronic components (power devices) that have poor performance and generate a large amount of heat are mounted on a ferrous alloy, heat accumulates at the joint between the ferrous alloy and the electronic component, causing overheating of the electronic component and causing damage to the metal substrate. The problem was that it destroyed the electronic components of the device.

This invention was made by focusing on such conventional problems, and it is possible to select a base metal according to the specifications of electronic components to be mounted on a gold R board. The purpose of this configuration is to improve the reliability of S construction of metal substrates.

[Means to solve the problem]

In the present invention, in the structure of a metal substrate in which a wiring layer is laminated on a base metal with an insulating layer interposed therebetween, and electronic components are mounted on the wiring layer, the base metal is mounted with electronic components that generate a large amount of heat. a first base metal made of a material with a high thermal conductivity; and a material with a small coefficient of thermal expansion on which an electronic component that generates less heat than the electronic component mounted on the first base metal is mounted. The first and second base metals are bonded to each other in the direction in which the insulating layer and the wiring layer are laminated (perpendicular to this direction).

(Function) The first base metal has a high thermal conductivity, so it can effectively dissipate the heat of the mounted electronic components, and the second base metal has a small coefficient of thermal expansion and a low thermal conductivity. Therefore, heat from electronic components that generate a large amount of heat is difficult to be transmitted through the base metal.

(Example) The present invention will be explained below based on the drawings.

FIG. 1 is a diagram showing an embodiment of the present invention.

First, the configuration will be explained.

The base metal 9 of the metal substrate 1 is composed of an iron-based alloy 10 and aluminum 2. A wiring layer 4 is laminated on the base metal 9 with an insulating layer 3 interposed therebetween.

The two base metals 9 are the insulating layer 3 and the wiring layer 4.
The epoxy resin adhesive 1 is attached to each other in the direction perpendicular to the stacking direction (vertical direction in the drawing) (horizontal direction in the drawing).
1.

A wiring layer 4 is laminated on the iron-based alloy 10 of the base metal 9 with an insulating layer 3 interposed therebetween, and a semiconductor element 5 having a small amount of heat is further laminated thereon. A wiring layer 4 is laminated on the aluminum base metal 9 with an insulating layer 3 interposed therebetween, and a semiconductor element (power device) 6 which generates a large amount of heat is further laminated thereon. The semiconductor element 5 is the wire 7
It is electrically connected to the wiring @4, and the connection part is connected by ultrasonic bonding. Power device 6 is terminal 1
It is electrically connected to the wiring layer 4 by 5, and the connection part is connected by solder 8.

Next, the effect will be explained.

Since the power device 6 is mounted on the base metal 9 made of aluminum 2, the heat generated by the power device 6 is radiated to the aluminum 2, which has a high heat transfer rate of 11, and is further radiated into the air. Since no heat is accumulated at the joint between the power device 6 and the metal substrate 1, temperature rise does not occur, and element destruction due to overheating can be prevented.

Since the semiconductor element 5 with a small heat generating part is mounted on the iron-based alloy 10 which exhibits little thermal expansion due to temperature differences in the external environment, the heat from the semiconductor element (power device) 6 which generates a large amount of heat is transferred to the base metal 9. It is transmitted through <, iron-based alloy 10
Since the stress on the iron-based alloy 10 can be reduced due to less thermal expansion, peeling of the iron-based alloy 10 and the semiconductor element 5 due to thermal expansion can be prevented.

As described above, the reliability of the structure of the metal substrate 1 can be improved.

FIG. 2 shows an example of the structure of the base metal. The shape of the base metal can be arbitrarily set depending on the arrangement, location, and circuit configuration of the electronic components to be mounted.

Base metal 9 on which semiconductor element 5 with low heat generation is mounted
An iron-based alloy 10 is selected for the base metal 9 on which the power device 6 that generates a large amount of heat is mounted, and aluminum 2 is selected for the base metal 9.

FIG. 3 shows another embodiment.

First, the configuration will be explained.

The base metal 9 of the metal substrate 1 is composed of copper 12 and iron-based alloy 10. A wiring layer 4 is laminated on the base metal 9 with an insulating layer 3 interposed therebetween. The two base metals 9 are bonded together with an epoxy resin adhesive 11 in a direction perpendicular to the direction in which the insulating layer 1i3 and the wiring layer 4 are laminated (vertical direction in the drawing) (in the horizontal direction in the drawing). A wiring layer 4 is laminated on the copper 12 of the base metal 9 via an insulating layer 3, and an LS 114 which generates a large amount of heat is laminated on the wiring layer 4. A wiring N4 is laminated on a base metal 9 and an iron-based alloy 10 with an insulating layer 3 interposed therebetween, and a chip component 13 with a small amount of heat is mounted on the wiring layer 4. LSI
II is electrically connected to the wiring @4 by a terminal, and the connection portion is connected by solder 8. The dip part 13 is electrically connected to the wiring 114 by solder 8.

The one for fishing will be explained below.

Since the LSI 14, which is a heating element, is mounted on the base metal 9 made of copper 12, the heat generated by the LS r 14 is radiated to the copper 12, which has high thermal conductivity, and is further radiated into the air. Therefore, no heat is accumulated at the joint between the copper 12 and the LS 114, so no temperature rise occurs, and element destruction due to overheating can be prevented.

The chip component 13, which generates a small amount of heat, is mounted on the iron-based alloy 10, which has little thermal expansion due to temperature differences in the external environment, so the thermal expansion of the iron-based alloy 10 is small, and the stress on the iron-based alloy 10 can be reduced. It is possible to prevent element peeling between the iron-based alloy 10 and the chip component 13 due to thermal expansion.

As described above, the reliability of the structure of the metal substrate 1 can be improved.

〔effect〕

As described above, according to the present invention, in the structure of a metal substrate in which a wiring layer is laminated on a base metal via an insulating layer and electronic components are mounted on the wiring layer, the base metal A first base metal made of a material with high thermal conductivity is mounted with electronic components that generate a large amount of heat, and an electronic component that generates less heat than the electronic components mounted on the first base metal is mounted. at least a second base metal made of a material with a small coefficient of thermal expansion;
Since the base metals are bonded to each other in a direction perpendicular to the direction in which the insulating layer and the wiring layer are laminated, the heat generated by electronic components that generate a large amount of heat is transferred to the base metal that has high thermal conductivity. Because heat is radiated into the air through
Since heat does not accumulate at the joint between the metal substrate and the electronic component that generates a large amount of heat, there is no rise in temperature, and element destruction due to overheating can be prevented. Electronic components that generate less heat are mounted on base metals that have less thermal expansion due to temperature differences in the external environment, so the base metal has less thermal expansion and stress can be reduced. Prevents elements from peeling off from parts. From the above, gold j! The reliability of the structure of the board and electronic components can be improved.

[Brief explanation of the drawing]

FIG. 1 shows one embodiment of the present invention, FIG. 2 shows the structure of the base metal, FIG. 3 shows another embodiment of the invention, and FIG. 4 shows the structure of the base metal. A diagram showing a conventional mounting structure of a metal substrate. 1... Metal substrate 2... Aluminum 3.
...Insulating layer 4...Wiring layer 5...Semiconductor element with low heat value 6...Semiconductor element (power device) with high heat value 7...Wire 8...Solder 9...Base gold 1iE 10... Iron alloy 11... Epoxy resin adhesive 12... Copper 13... Chip parts 14.
...LSI 15...terminal patent applicant
Nissan Motor Co., Ltd. 1-1-/L the 4

Claims (1)

[Claims] In the structure of a metal substrate in which a wiring layer is laminated on a base metal via an insulating layer, and electronic components are mounted on the wiring layer,
The base metal includes a first base metal made of a material with high thermal conductivity on which electronic components that generate a large amount of heat are mounted;
at least a second base metal made of a material with a small coefficient of thermal expansion on which an electronic component that generates less heat than the electronic component mounted on the base metal is mounted, and the first and second base metal are A structure of a metal substrate, characterized in that the insulating layer and the wiring layer are bonded to each other in a direction perpendicular to the direction in which they are laminated.