JPH0677649A - Multilayer circuit board, electronic module, and electronic device - Google Patents

Abstract

PURPOSE:To obtain a next generation multilayer circuit board, and a module and electronic device employing the multilayer circuit board, for forming a multilayer thin film circuit having high density wiring while suppressing warp of board and enhancing reliability in connection. CONSTITUTION:In a multilayer circuit board comprising a board 1 and a multilayer thin film circuit 4 formed of a heat resistant dielectric film 5 and a wiring on the board 1, the heat resistant dielectric film 5 is composed of an organic heat resistant material and an inorganic powder material where the coefficient of linear expansion of the organic heat resistant material is set substantially equal to that of the wiring 6 and the coefficient of linear expansion of the heat resistant dielectric film 5, formed by admixing inorganic powder to the organic heat resistant material, is set substantially equal to that of the board 1. The multilayer circuit board is employed in an electronic module and an electronic device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer circuit board, a module and an electronic device using the same, and particularly to a high density circuit board.
The present invention relates to a highly accurate and highly reliable multilayer circuit board, module, and electronic device. In particular, it is used for an electronic device such as an electronic computer whose packaging density determines the superiority or inferiority of a product.

[0002]

2. Description of the Related Art Conventionally, in an electronic device such as a large-scale computer which is strongly required to have an improved processing speed, it is necessary to shorten the connection between the elements as in the case of increasing the speed of active elements such as LSI in order to improve the performance of the apparatus. there were. From such a background, in the technology of the LSI mounting board having high-density wiring, there has been a strong demand for realization of a multilayer circuit board technology capable of forming fine high-density wiring suitable for high-speed signal transmission. A multi-layer circuit board in which a heat-resistant insulating film and a multi-layer thin-film circuit in which wiring of a conductive material such as copper is formed on a board is advantageous for high-density wiring and accompanying high-speed signal transmission. For this reason, its use as a circuit for various electronic devices has been studied.

In particular, a multilayer circuit board used in computers, workstations, communication devices, and exchanges has a large number of LSIs and electronic components mounted on the substrate, and enormous wiring for connecting the mounted components to the substrate. Had to be achieved above. This has brought about a higher density of wiring, a larger substrate and an increased number of circuit layers. As an example,
In current supercomputers and super-large electronic devices, several layers of multi-layer thin film circuits are formed on an inorganic multi-layer substrate of about 200 to 300 mm square. If this becomes the next generation, the size of the substrate will be further increased and the number of layers of the multilayer thin film circuit will inevitably exceed 10.

Further, if it is further spread, it is obvious that the multi-layer thin film circuit can be highly densified as compared with an inorganic multi-layer substrate or a multi-layer printed circuit board manufactured by using a printing technique or the like. Therefore, there is a large tendency for electronic circuits to be formed of multilayer thin film circuits. As a result, the inorganic multilayer substrate or the printed circuit board is necessarily thin, whereas the multilayer thin film circuit layer is thick. In such a high-density board, it is necessary to newly examine the warpage of the entire multilayer circuit board. This warp is basically due to the difference in linear expansion coefficient between the inorganic multi-layer substrate or the printed circuit board and the multi-layer thin film circuit layer, which are bases.

That is, when forming a multilayer thin film circuit,
Usually, the organic insulating film used as the heat resistant insulating film is baked at 100 to 500 ° C. depending on the material constitution. In this case, if there is a difference in the coefficient of linear expansion between the substrate and the heat-resistant insulating film, after the heat-resistant insulating film is baked, the entire multilayer circuit board is gradually cooled from the solidification temperature to room temperature, and the whole multilayer circuit board looks like a bimetal. It will be warped. This poses a serious problem as a circuit element for various large electronic devices.

[0006] As an example, a so-called
When PIQ is formed to a film thickness of 0.6 mm, the entire substrate has a thickness of about 0.
It will be warped by 4 mm. This is the conventional small 100 mm
In a square substrate, the warp is about 0.1 mm. Thickness 1
For a 0 mm substrate, the warpage is about 0.03 mm. The magnitude of these warps has hardly caused a problem in a multilayer circuit board having a low wiring density.

What is problematic is that the multi-layer thin film circuit is peeled off from the substrate due to the difference in the linear expansion coefficient. If there is no peeling, the multi-layer thin film circuit can be sufficiently used as a multi-layer circuit substrate. However, in the next-generation multi-layer circuit board for supercomputers, the board becomes large and thin and the multi-layer thin film circuit becomes thick, so the above warpage becomes extremely large, which is a drawback in forming the multi-layer thin film circuit. Was becoming.

[0008]

In the conventional multilayer circuit board described above, when the wiring of the multilayer thin film circuit is formed by electroplating, the formed wiring is coated with a heat resistant insulating film and then cured. Furthermore, after that, the surface was flattened. In this case, the surface of the heat-resistant insulating film was mechanically polished, but if the entire substrate was warped, there was a problem that the flattening accuracy would be extremely deteriorated.

Further, the above-mentioned problem that the precision of flattening is extremely deteriorated causes the following problems. Usually, in this flattening process, it is necessary to reduce the thickness variation of the multilayer thin film circuit layer to 10% or less of the multilayer thin film circuit layer.
That is, when the thickness of the multilayer thin film circuit layer is 0.6 mm,
It must be polished with an accuracy within 60 μm. If the warp of the multilayer circuit board as a whole is less than 60 μm, the polishing with the above precision cannot be performed. Further, in the exposure process, when the exposure is performed by a normal contact method, it is difficult to focus on the entire surface when the multilayer circuit board is warped, and there is a problem that sufficient resolution of the pattern cannot be obtained. .

Further, when electronic parts such as LSI are mounted on the multilayer circuit board and the whole board is sealed, the reliability of connection of these electronic parts becomes a problem. That is, a temperature cycle is added every time the electronic component is connected to the multilayer circuit board. Each time, the substrate warps or returns to its original shape. This temperature cycle also occurs due to heat generation due to energization and changes in the outside air temperature. Therefore, extreme repetitive stress is applied to the connection portion, and the reliability of the connection is significantly reduced.

As described above, since the next-generation multilayer circuit board requires high-density wiring and high accuracy, the problem of warpage of this multilayer circuit board has become apparent. Further, it is necessary to reduce the warp in view of formation of the multilayer thin film circuit and high reliability of the connection part of the electronic component. In concrete terms,
The 200 mm square substrate had a problem that its warpage must be within about 50 μm.

The following proposals have been made for the above problems. For example, RP. Himmel et
al. , "Fabrication of Large"
-Area, Thin-Film Multilay
er Substrates ”ISHM '89 P
roseceings, P454-461 (1989)
Have been introduced to. This is a method of eliminating the difference in linear expansion coefficient between the substrate and the heat resistant insulating film.

However, this method introduces some new problems. That is, the coefficient of thermal expansion of the organic material forming the heat resistant insulating film is originally higher than that of the inorganic material. Reducing this to the same extent as an inorganic material usually involves sacrificing other properties. In particular, a new serious problem arises in that the adhesion between the heat-resistant insulating film and the substrate and between the heat-resistant insulating films is significantly deteriorated. Moreover, the coefficient of linear expansion of a metal such as copper that is usually used as a wiring material is higher than that of an inorganic material used for a substrate. Reducing the linear expansion coefficient of the heat resistant insulating film results in increasing the difference between the linear expansion coefficient of the wiring material and the linear expansion coefficient of the heat resistant insulating film, and increasing the stress acting between them. Therefore, there is a problem that the reliability of the thin film circuit is significantly deteriorated.

In order to reduce the warp of the multilayer circuit board which causes such an adverse effect, the difference in the coefficient of linear expansion between the substrate and the heat resistant insulating film is reduced and the adhesion between the substrate and the heat resistant insulating film is secured. It is necessary. In order to secure the connection reliability of the wiring in the above-mentioned multilayer thin film circuit, it is necessary to reduce the difference in the coefficient of linear expansion between the wiring and the heat resistant insulating film and secure the adhesion between them. When these conditions are combined, it is necessary that the substrate, the heat resistant insulating film, and the multilayer thin film circuit wiring have substantially the same linear expansion coefficient. However, the linear expansion coefficient of the substrate and the thin film circuit wiring is
Their materials are usually ceramic and gold, copper, etc., and are therefore generally different. Therefore, it is difficult to obtain a heat resistant insulating material that satisfies the above conditions.

The present invention solves the above-mentioned problems of the prior art by other means without applying a heat-resistant insulating film material satisfying the above conditions. In a next-generation multilayer circuit board, a multilayer circuit is provided. It is a first object of the present invention to provide a multilayer circuit board which can reduce the warp of the board, can form a thin film circuit of high-density wiring, and ensure the reliability of connection. A second object of the present invention is to provide an electronic module incorporating a multilayer circuit board in which warpage of the board is reduced, a multilayer thin film circuit of high-density wiring is formed, and reliability of connection is secured. Especially. further,
A third object of the present invention is to provide an electronic device incorporating the electronic module and having high-speed processing performance.

[0016]

In order to achieve the above-mentioned first object, that is, there is no difference in the coefficient of linear expansion from the substrate, and there is also no difference in the coefficient of linear expansion from the wiring material of the multilayer thin film circuit. Instead of using an insulating film material, the structure of the first invention relating to a multilayer circuit board is a multilayer circuit board comprising a substrate and a multilayer thin film circuit in which a heat resistant insulating film and wiring are formed on the substrate. A heat insulating organic film is formed from a mixture of a heat resistant organic material and an inorganic material powder, and the coefficient of linear expansion of the heat resistant organic material is equal to the coefficient of linear expansion of the wiring material of the thin film circuit,
The coefficient of linear expansion of the heat resistant insulating film formed by mixing the inorganic material powder with the heat resistant organic material is equal to the coefficient of linear expansion of the substrate.

In order to achieve the above-mentioned first object, another structure of the first invention relating to a multilayer circuit board is a heat-resistant insulating film or a separately prepared heat-resistant insulating film formed on a multilayer thin-film circuit layer formed on the board. In a multi-layer circuit board obtained by adhering a multi-layer thin film circuit layer in which wiring is formed on a part of this film, the adhesive used for this adhesion is composed of a heat-resistant organic material and an inorganic material powder,
The heat-resistant organic material has a coefficient of linear expansion equal to that of the wiring material of the multilayer thin film circuit, and the adhesive has a coefficient of linear expansion equal to that of the substrate. Further, even when a multilayer thin film circuit layer in which wiring is formed is adhered to a part of a heat-resistant insulating film separately formed on a substrate to form a multilayer circuit board, the adhesive material used for the adhesion is the same as described above. The same shall apply.

Further, copper or gold is used for the wiring material of the multilayer thin film circuit, and the heat-resistant insulating film or adhesive has a linear expansion coefficient of 10 ppm / K to 20 ppm / K and the inorganic material is the heat-resistant organic insulating material. Powder is mixed, and even if this linear expansion coefficient is the same as or larger than that of the substrate, 7 ppm /
K is set to be in a large range. further,
A polyimide resin is used as the heat-resistant organic insulating material, a thick film substrate insulated with ceramics or glass is used as the substrate, and polyimide resins 30 to 9 are used as the heat-resistant insulating film or the adhesive.
Fused silica glass powder 7 with 0 Vol% and average particle size of 2 μm or less
A mixture formed with 0 to 10 Vol% is used.

Furthermore, as the heat resistant insulating film or adhesive, it is preferable to use a mixture of 30 to 90% by volume of a polyimide resin and an inorganic material powder containing quartz as a main component and having a linear expansion coefficient of 3.5 ppm / K or less. It was done. Furthermore, the wiring in the multilayer thin film circuit is formed by forming another metal film on a part of the surface of the wiring of copper or gold and multiplexing the wiring. Furthermore, in order to achieve the above second object, the configuration of the second invention relating to an electronic device is an electronic module having a multilayer circuit board, an LSI element mounted on the multilayer circuit board, and a cap for sealing these elements. In the above, the multi-layer circuit board having the structure according to the first aspect of the invention is used as the circuit board-embedded board. Furthermore, in order to achieve the above-mentioned third object, the structure of the third invention relating to the electronic device is an electronic device in which a large number of electronic elements are incorporated. It uses a module and is built in.

[0020]

The function of each of the above technical means is as follows.
According to the structure of the first invention, in a multilayer circuit board comprising a substrate and a heat-resistant insulating film laminated on the substrate and a multilayer thin-film wiring, the heat-resistant insulating film comprises a heat-resistant organic material and an inorganic material powder. Of the heat-resistant insulating film formed by mixing the heat-resistant organic material with the inorganic material powder, and combining the linear expansion coefficient of the heat-resistant organic material with the linear expansion coefficient of the material of the multilayer thin-film wiring. Since the coefficient of linear expansion is made equal to the coefficient of linear expansion of the substrate, it has the following functions. (1) The warp of a large-sized substrate, which is a next-generation multilayer circuit board and has a multilayer thin-film circuit having a large number of layers, is reduced, and the manufacture of this board is facilitated. (2) By ensuring the adhesion between the wiring and the heat-resistant insulating film in the thin-film multilayer circuit, and by distributing the stress, thermal, mechanical, and electrical reliability in the multilayer thin-film circuit is secured. It

(3) Adhesion between the substrate and the heat-resistant insulating film is ensured, and the stress generated at the interface is reduced, so that the reliability of the thermal, mechanical and electrical connection between the substrate and the multilayer thin film circuit is improved. Secure. (4) As a result of the warp of the multilayer circuit board becoming smaller, the connection between the board and an electronic component such as an LSI mounted on the board becomes easier, and the fluctuation range of the warp of the board due to temperature change is reduced. Therefore, the repetitive stress applied to the connection between the board and the mounted electronic components and between the mounted electronic components is reduced,
The reliability of these connections is improved, and at the same time, the connection reliability of the sealing portion of the substrate is improved. (5) The above-mentioned actions work together to improve the manufacturing yield of the multilayer circuit board, and to extend the life of the board.

According to the structure of the second invention, in the electronic module having the multilayer circuit board, the LSI mounted on the board, and the sealing cap for sealing them, the first multilayer circuit board is provided. Since the multilayer circuit board of the invention is used, a highly reliable electronic module having a short connection distance between the circuit elements can be obtained. According to the configuration of the third invention, in an electronic device incorporating a large number of electronic elements, since the electronic module according to the configuration of the second invention is incorporated in this electronic element, high-density wiring and high processing speed are achieved. It becomes an electronic device.

[0023]

Embodiments of the present invention will be described below with reference to FIGS. [Embodiment 1] FIG. 1 is a sectional view of a multilayer circuit board according to an embodiment of the present invention. In this embodiment, the connection reliability at the interface between the base substrate and the multilayer thin film circuit is secured, and the warpage of the multilayer circuit substrate is reduced, so that the adhesion between the substrate and the heat resistant insulating film is secured. Thus, the difference in linear expansion coefficient between the two is reduced. In order to secure the connection reliability of the wiring in the multilayer thin film circuit, the heat resistant organic material of the heat resistant insulating film and the wiring material of the multilayer thin film circuit are secured so as to ensure the adhesion between the wiring and the heat resistant insulating film. The difference in the coefficient of linear expansion between and is reduced.

In general, when a material having high adhesiveness is selected, a material having a high linear expansion coefficient is obtained, and a material having a low linear expansion coefficient has low adhesiveness. Especially, the linear expansion coefficient is 10p
If the material is less than pm / K, the adhesiveness will be drastically lowered and it will be unsuitable. Therefore, in this embodiment, copper (linear expansion coefficient: 17 ppm / K) and gold (linear expansion coefficient: 14 p) applied as wiring materials are used.
pm / K) and aluminum (coefficient of linear expansion: 23 ppm / K), a heat-resistant organic material having a coefficient of linear expansion equivalent to that of the heat-resistant insulating film and the wiring of the multilayer thin film circuit is secured. . In addition, in order to reduce the warp with the substrate, the linear expansion coefficient of the heat-resistant insulating film itself is lowered by mixing inorganic powder with this heat-resistant organic material, so that the linear expansion coefficient of the substrate is close to that of the substrate. Is.

In FIG. 1, 1 is a multilayer (5 layers in this embodiment) ceramic substrate (hereinafter, referred to as 200 mm each).
2 is an alumina sheet, 3 is a conductor wiring on the surface and inside of the alumina sheet 2 (hereinafter, simply referred to as conductor wiring), 4 is a multilayer thin film circuit on the substrate 1, and 5 is a multilayer (this embodiment). In the example, a heat-resistant insulating film made of polyimide (20 layers) (hereinafter, simply referred to as heat-resistant insulating film), and 6 are wirings in the multilayer thin film circuit 4 (hereinafter simply referred to as thin film wiring). This multilayer circuit board was manufactured in the following order.

(1) A plurality of green alumina sheets 2 are formed. Conductor wiring 3 is formed on each alumina sheet 2 by using a tungsten paste. Part of the paste is also filled in the via holes in the alumina sheet 2. These alumina sheets 2 are laminated in a required number of five sheets based on the guide holes formed at the four corners. This laminated body was pressed at a temperature of 120 ° C.
The substrate 1 is formed by being heated to 600 ° C. and changing from green to ceramic.

(2) On the surface of the substrate 1, Cr / Cu is formed as a base film for plating. After that, a photosensitive resist is coated, and after exposure and development, the resist film is patterned. (3) In the resist film, the thin film wiring 6 is formed in the groove by electrolytic copper plating. After that, the entire resist film and the Cr / Cu base film between the thin film wirings 6 are removed, and the copper surface of the thin film wirings 6 is coated with nickel by electroless plating.

(4) Between the thin film wirings 6 and on the thin film wirings 6, the heat resistant insulating film 5 is applied and baked at 350 ° C. The material of the heat resistant insulating film 5 is composed of polyimide and fused silica powder having an average particle size of 2 μm. The polyimide is BPDA (3,
3 ', 4,4',-biphenyl tetraca
rboxylic dianhydride),
DDE (Diamino diphen) as a diamine
yl ether) and PDA (P-phenylene)
diamine), the amount of DDE is 10 wt%, and the terminal reactive group of silicon is added thereto. The linear expansion coefficient of polyimide alone after baking is 10 pp
m. In addition, 1 layer of fused silica powder is included in polyimide.
It is mixed with 0 Vol% and the apparent coefficient of linear expansion is 8.5.
It is ppm / K. Substrate 1 on which conductor wiring 3 is formed
The coefficient of linear expansion of was 7.5 ppm / K. Further, the peel strength with respect to the substrate, alumina, is about 400 g / cm.

(5) The heat resistant insulating film 5 on the thin film wiring 6 is polished and removed by using a polishing board. (6) By repeating the method of (2) to (5), a total of 20 thin film circuits are formed. The width and the film thickness of the wiring are both 30 μm. A multilayer circuit board was formed using the materials described above and by the manufacturing method. As a result, the warpage of the entire substrate is about 1
The thickness was 0 μm, and the final exposure and insulating film polishing steps could be manufactured without any problems. In addition, the resistance value of the wiring connection portion was 1 mΩ or less, and no defect in the wiring connection portion other than disconnection due to adhesion of dust was observed.

[Embodiment 2] Next, another embodiment of the first invention will be described. In another example according to the present invention, a multilayer circuit board having the same structure as in [Example 1] was prepared by changing the mixing amounts of the substrate material, the organic insulating material and the fused silica.
The substrate 1 is made of mullite, and the conductor wiring 3 is [Example 1].
Tungsten was used as in. As the heat resistant insulating film 5, a mixed system of polyimide and fused quartz was used. The polyimide has the same basic composition as in [Example 1],
The amount of DDE in the diamine was set to 25 wt%. Thin film wiring 6
Used copper in the same manner as in [Example 1].

The coefficient of linear expansion of the heat-resistant insulating film after baking was 10.5 ppm / K. The linear expansion coefficient of the mullite substrate 1 on which the wiring was formed was 3.5 ppm / K. The coefficient of linear expansion of only polyimide was 17 ppm, but it was lowered by mixing 40 vol% of fused silica powder having an average particle diameter of 1.5 μm with polyimide. The peel strength between the heat resistant insulating film 5 and the substrate 1 was about 550 g / cm. Using the above materials, and by the manufacturing method,
A multilayer circuit board was formed. Warpage of the entire substrate is about 60 μm
Therefore, it was possible to manufacture without any problem until the final step of exposure and polishing of the insulating film. The resistance value of the wiring connection portion was 1 mΩ or less, and the defect of the wiring connection portion could not be observed except the disconnection due to the adhesion of dust or the like.

[Embodiment 3] Next, still another embodiment of the first invention will be described. In the structure of still another example according to the present invention, a multilayer circuit board was prepared using the same substrate material and heat resistant insulating film material as in [Example 2]. Thin film wiring 6
Used gold. The base film was Cr / Cu / Au, and the step of coating the surface of the thin film wiring 6 with nickel plating was omitted. As for the heat-resistant organic material polyimide, the DDE amount in the diamine was set to 25 wt% as in [Example 2], and 70 vol% of mullite powder having a linear expansion coefficient of 3.5 ppm / K and an average particle diameter of 1 μm was mixed with this polyimide. . The linear expansion coefficient after baking only polyimide was 17 ppm, and the apparent linear expansion coefficient of the heat-resistant insulating film 5 of the mixture was 9.0 ppm / K. The peel strength between the heat-resistant insulating film 5 and the mullite substrate 1 is about 600 g /
It was cm. With the above materials and manufacturing method,
A multilayer circuit board was formed. Warpage of the entire substrate is about 50 μm
Therefore, the process of exposure and polishing of the insulating film could be manufactured without any trouble. The resistance value of the wiring connection portion was 1 mΩ or less, and the defect of the wiring connection portion could not be observed except the disconnection due to the adhesion of dust or the like.

[Embodiment 4] Next, still another embodiment of the first invention will be described. The structure of still another embodiment according to the present invention is the same as that of [Example 1], and a multilayer circuit board is prepared by changing the substrate material and the heat-resistant insulating film material. The substrate 1 is made of glass ceramics, the conductor wiring 3 is made of copper as in [Example 1], and the thin film wiring 6 is
Copper was used as in 1). As the glass ceramics, a mixed material of alumina powder and borosilicate glass was used.
The basic composition of the polyimide used for the heat-resistant insulating film 5 is
Same as (Example 1), except that the DDE amount in the diamine was set to 30 wt%, and fused polyimide powder was added to this polyimide to 7 wt%.
0 Vol% was added.

The coefficient of linear expansion of the polyimide alone after baking was 20 ppm, and the apparent coefficient of linear expansion of the heat resistant insulating film 5 after the addition of the fused silica powder was 6.5 ppm / K. The linear expansion coefficient of the substrate 1 on which the conductor wiring 3 is formed is 4.0 p.
It was pm / K. The peel strength between the heat resistant insulating film 5 and the glass ceramic substrate 1 was about 650 g / cm. The manufacturing process is almost the same as in (Example 1), but the sintering of the glass ceramic laminate is performed in a hydrogen atmosphere at 95%.
Performed at 0 ° C. A multilayer circuit board was formed by using the above materials and manufacturing method. The warpage of the entire multilayer circuit board was about 30 μm, and the final exposure and polishing of the insulating film could be manufactured without any trouble. Resistance value at wiring connection is 1m
It was less than Ω, and no defect in the wiring connection part could be observed except for disconnection due to adhesion of dust or the like.

[Embodiment 5] Next, still another embodiment of the first invention will be described. Substrate 1 was produced in the same manner as in the manufacturing steps (1) to (3) of [Example 1] in the configuration of still another example according to the present invention. Further, the nickel plating on the copper surface of the thin film wiring 6 was further double-coated with electroless gold plating. Also,
The multilayer thin film circuit 4 is formed in 19 layers from the upper layer portion to the lower layer in FIG. 1 in the same manner as in [Example 1] on the glass substrate on which Cr / Cu is formed. Then, the wiring surface of the last layer was plated with gold. Next, except for the surface of the wiring conductor 3, the surface of the substrate 1 previously manufactured has a heat-resistant insulating film 5
Is further applied, and the multilayer thin film circuit 4 formed on the glass plate on the substrate 1 is pressure-bonded so that the wirings are connected to each other, and is baked at a temperature of 350 ° C. in that state.

The heat-resistant insulating film material is composed of a mixture of polyimide and fused silica powder having an average particle size of 2 μm.
The polyimide was composed of BPDA as an acid anhydride and DDE and PDA as a diamine in exactly the same manner as in (Example 1), and had a DDE amount of 10 wt%, to which a silicon end reactive group was added. This polyimide is mixed with 10 vol% of fused quartz powder. The coefficient of linear expansion of only polyimide after baking is 10 ppm, but the apparent coefficient of linear expansion of the mixture is 8.5 ppm / K. After that, Cr / C formed on the surface of the glass plate
The u layer was removed by etching. A multilayer circuit board was formed by using the above materials and manufacturing method. The warpage of the entire substrate was about 5 μm. The resistance value of the wiring connection portion was 1 mΩ or less, and no defect in the wiring connection portion other than disconnection due to adhesion of dust or the like could not be observed.

[Sixth Embodiment] Next, still another embodiment of the first invention will be described. FIG. 2 is a sectional view of a multi-layer circuit board according to another embodiment of the present invention. In the figure, the same symbols as those in FIG. The structure according to still another embodiment of the present invention is the same as that of the manufacturing process of [Embodiment 1], except that a multi-layer thin film circuit is formed on a base substrate and a multi-layer thin film circuit is separately formed. To do. Then, the separately formed multilayer thin film circuit is bonded onto the multilayer thin film circuit on the substrate to form a multilayer circuit substrate. In FIG. 2, 4 '
Is a separately formed multilayer thin film circuit, 10 and 10 'are surface conductor pads provided on the multilayer thin film circuits 4 and 4', 20 is a polyimide-based conductive resin, and 21 is a polyimide-based insulating adhesive layer. .

In this example, as in (Example 2), a multilayer circuit board was prepared by changing the amounts of the substrate material, the heat-resistant insulating film material and the fused silica mixed. Substrate 1 uses mullite,
The conductor wiring 3 was made of tungsten, and the thin film wiring 6 was made of copper. As the heat-resistant insulating film material, a mixed system of polyimide and fused silica was used. Similar to (Example 2), the basic polyimide composition was set as follows with the amount of DDE in the diamine being 25 wt%. Five layers of the multilayer thin film circuit 4 are formed on the mullite substrate 1. Separately, a five-layer multilayer thin film circuit 4'is formed by the same method. The multilayer thin film circuit 4'is formed by forming a film of Al on an alumina substrate and forming the film on the film.

At the stage of forming the five-layer multilayer thin film circuit 4 ', the Al film is dissolved with an etching solution and peeled from the alumina substrate. The surface conductor pads 10 'on the multilayer thin film circuit 4'are printed by using a conductive resin 20 whose main component is polyimide. The resin 20 is mixed with silver / palladium powder to ensure conductivity. In addition, on the surface of the multilayer thin film circuit 4,
A heat resistant insulating layer is printed with the above heat resistant insulating film material except for the portions of the conductor pads 10 to be connected to each other.

After that, the multi-layer thin film circuit 4 and the multi-layer thin film circuit 4'are made to face each other, and the pads 10 and 10 'of the surface conductors to be connected are adhered to each other with the polyimide conductive resin 20. , 4'are brought into close contact with each other by the heat-resistant insulating film material to form a polyimide-based insulating adhesive layer 21. Gradually heat in this state 350
The temperature is raised to 0 ° C. to fix between the multilayer thin film circuits 4 and 4 ′. The heat-resistant polyimide-based insulating adhesive layer 21 is
In addition to the function of interlayer insulation, it functions to bond both the multilayer thin film circuits 4 and 4 '. The warpage of the entire multilayer circuit board manufactured by the above method is about 20 μm, and the resistance value of the wiring connection portion is 1 mΩ.
The results were as follows, and there was no defect in the wiring part other than the disconnection due to adhesion of dust or the like.

The above-described embodiment is merely an example, and the present invention is not limited to this, and many modes are conceivable. In the examples of [Example 1] to [Example 6], a thick film substrate made of ceramic or the like was used as the substrate, but it goes without saying that a printed circuit board or a laminated substrate can be used. In a printed circuit board, it is generally practiced to match the coefficient of linear expansion of copper, which is wiring, with two types of constituent materials: an organic insulating material and copper.
In the case of a multilayer circuit board, on the other hand, there are three types of material systems, and since they are formed on a ceramic board having a low linear expansion coefficient, they differ.

In general, the effect of each of the above embodiments is that when the wiring material of the multilayer thin film circuit is copper or gold, as shown by the real value in each embodiment, the heat resistant organic insulating material is used. Linear expansion coefficient is 10ppm / K or 20p
pm / K, and the linear expansion coefficient of the heat-resistant insulating film obtained by mixing the inorganic material powder with pm / K is the same as or larger than that of the substrate, but is in the range of 7 ppm / K larger than the linear expansion coefficient of the substrate. This means that even when the wiring in the multilayer thin film circuit is a multiple wiring in which another metal film is formed on a part of the wiring surface of copper or gold, the same effect can be realized if the above conditions are satisfied. . Further, the wiring material 6 of the multi-layer thin film circuit is not limited to gold and copper used in each embodiment, but aluminum, nickel, etc. can be applied.

Further, in the above embodiments, the heat-resistant organic insulating material of the thin film circuit is not limited to the polyimide having the constitution in each of the embodiments, but other polyimide materials as well as materials such as epoxy can be applied. When polyimide is used as the heat-resistant organic insulating material and a thick film substrate insulated with ceramics or glass is used as the substrate, the heat-resistant insulating film is polyimide 30 to 90 VOL% and the average particle diameter is 2 μm.
The above effect can be realized by using a film composed of the following fused silica glass powder 70 to 10 vol%.

Here, the content of the fused silica glass powder in the polyimide film is set to 70 to 10 Vol% because the commonly used alumina substrate (coefficient of linear expansion: 8 ppm / K) and glass ceramic substrate (coefficient of linear expansion: (3.5 ppm / K) and the mullite substrate (coefficient of linear expansion: 3.5 ppm / K) to have the same linear expansion coefficient and to keep the warpage of the substrate within the target value. Further, in the above examples, the fused silica glass powder was used as the mixture with the polyimide, but instead of the fused silica glass powder, the coefficient of linear expansion containing quartz as the main component was 3.5 pp.
The above effect can also be achieved by using an inorganic material powder of m / K or less. Also, in the same manner as above, when a multilayer thin film circuit is separately prepared and bonded to a multilayer thin film circuit layer on a ceramic substrate as described in [Example 6], the same applies to this adhesive material. However, the same effect can be realized.

[Embodiment 7] Next, an embodiment of the second invention will be described. FIG. 3 is a sectional view of an electronic module according to another exemplary embodiment of the present invention. In the figure, the same symbols as those in FIG. In FIG. 3, M is an electronic module, B is a multilayer circuit board including a ceramic substrate 1 and a multilayer thin film circuit 4, 7 is a back surface pad of the ceramic substrate 1, 8 is high temperature solder, 9 is a connection pin, and 10 is a multilayer. Surface conductor pad of thin film circuit 4, 11 is medium temperature solder, 12 is LSI element, 13 is a rubber plate having heat resistance and good thermal conductivity, 14 is a sealing conductor around ceramic substrate 1, 15 is low temperature solder, 16 Is a sealing cap, and 17 is a cooling fin. In FIG. 3, an electronic module M according to an embodiment of the present invention includes an LSI element 12 and a multilayer circuit board B manufactured in each embodiment of the first invention.
And a sealing cap 16 that seals them, and is manufactured by the following process.

The electronic module M according to the embodiment of the present invention shown in FIG. 3 is provided with a pad 7 on the back surface of the ceramic substrate 1, and a high temperature solder 8 is used for the pad 7 to form about 350.
It is heated to ° C and the connecting pin 9 is connected and fixed. On the surface conductor pad 10 of the multilayer thin film circuit 4,
Medium temperature solder 11 is placed and heated to about 250 ° C and LS
The I element 12 was electrically connected and mounted. Finally, the sealing conductor 14 around the ceramic substrate 1 has a low temperature solder 15
, Is heated to about 200 ° C., the Kovar sealing cap 16 is connected, and the electronic module M is completed. Cooling fins 17 for air-cooling the LSI element 12 are formed in the sealing cap 16, and between the LSI element 12 and the sealing cap 16,
A rubber plate 13 having heat resistance and good heat conductivity is interposed between them to ensure heat conduction between them.

[Embodiment 8] Next, an embodiment of the third invention will be described. FIG. 4 is an external view of a logic package according to another embodiment of the present invention. In FIG. 4, the logic package according to the embodiment of the present invention was manufactured using the module M manufactured in (Embodiment 7) of the second invention. In FIG. 4, M is a module manufactured in (Embodiment 7) of the second invention, and 19 is a printed circuit board. The logic package according to the embodiment of the present invention shown in FIG.
16 electronic modules M were mounted on the top to form the logic package P shown in FIG. A computer can be configured by combining the logic package P, the storage package, and the input / output processing package.

[0048]

As described in detail above, according to the present invention, firstly, in the next-generation multilayer circuit board, the warp of the multilayer circuit board is reduced and a multilayer thin film circuit of high-density wiring is formed. It is possible to provide a multilayer circuit board in which the reliability of connection is ensured. Secondly, it is possible to provide an electronic module incorporating a multilayer circuit board in which warpage of the board is reduced, a multilayer thin film circuit of high-density wiring is formed, and connection reliability is ensured. .
Furthermore, thirdly, it is possible to provide an electronic device incorporating the electronic module and having high-speed processing performance.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a multilayer circuit board according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a multilayer circuit board according to another embodiment of the present invention.

FIG. 3 is a cross-sectional view of an electronic module according to another embodiment of the present invention.

FIG. 4 is an external view of a logic package according to another embodiment of the present invention.

[Explanation of symbols]

 1 substrate 2 alumina sheet 3 conductor wiring 4, 4'multilayer thin film circuit 5 heat resistant insulation film 6 thin film wiring 7 backside conductor pad 8 high temperature solder 9 connection pins 10, 10 'conductor pad 11 medium temperature solder 12 LSI element 13 good thermal conductivity Rubber 14 Sealing conductor 15 Low temperature solder 16 Sealing cap 19 Printed circuit board 20 Conductive resin 21 Insulating adhesive layer B Multi-layer circuit board M Electronic module P Logic package

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI Technical display location G06J 1/00 7232-5B H01L 23/14 27/01 311 8418-4M

Claims (13)

[Claims] 1. A multilayer circuit board comprising a substrate and a multilayer thin film circuit having a heat resistant insulating film and wiring formed on the substrate, wherein the heat resistant insulating film is a mixture of a heat resistant organic material and an inorganic material powder. The coefficient of linear expansion of the heat-resistant organic material is equal to the coefficient of linear expansion of the wiring material of the multilayer thin film circuit, and the coefficient of linear expansion of the heat-resistant insulating film obtained by mixing the heat-resistant organic material with an inorganic material powder is A multilayer circuit board having a coefficient of linear expansion equal to that of the board. 2. A multilayer thin film circuit layer formed on a substrate,
In a multilayer circuit board made by bonding a separately prepared heat resistant insulating film or a multilayer thin film circuit layer in which wiring is formed on a part of this film, the adhesive used for this bonding is a heat resistant organic material and an inorganic material powder. The linear expansion coefficient of the heat-resistant organic material is equivalent to the linear expansion coefficient of the wiring material of the multilayer thin film circuit, and the linear expansion coefficient of the adhesive is equivalent to the linear expansion coefficient of the substrate. Characteristic multi-layer circuit board. 3. A multi-layer circuit board comprising a substrate and a multi-layer thin-film circuit layer having wiring formed on a part of a separately formed heat-resistant insulating film, wherein the adhesive used for this adhesion is heat-resistant. The thermal expansion coefficient of the heat-resistant organic material is equal to the linear expansion coefficient of the wiring material of the multilayer thin film circuit, and the linear expansion coefficient of the adhesive is the linear expansion coefficient of the substrate. A multilayer circuit board that is equivalent to 4. The wiring material of the multilayer thin film circuit is copper or gold, and the heat-resistant insulating film has a linear expansion coefficient of 10 ppm /
An inorganic material powder is mixed with a heat-resistant organic insulating material of K to 20 ppm / K, and the linear expansion coefficient is in the range of 7 ppm / K larger than the linear expansion coefficient of the substrate even if the linear expansion coefficient is the same as or larger than that of the substrate. Item 1. The multilayer circuit board according to item 1. 5. Copper or gold is used as the wiring material of the multi-layer thin film circuit, and the adhesive is made by mixing inorganic material powder with a heat resistant organic insulating material having a linear expansion coefficient of 10 ppm / K to 20 ppm / K. 4. The multilayer circuit board according to claim 2, wherein the expansion coefficient is in the range of 7 ppm / K larger than the linear expansion coefficient of the board even if the expansion coefficient is the same as or larger than that of the board. 6. The heat-resistant organic insulating material is polyimide resin, the substrate is a thick film substrate insulated with ceramics or glass, and the heat-resistant insulating film is polyimide resin 30 to 90.
Fused silica glass powder 70 with Vol% and average particle diameter of 2 μm or less
The multilayer circuit board according to claim 4, wherein a film formed by mixing 10 to 10 Vol% is used. 7. A polyimide resin is used as the heat-resistant organic insulating material, a thick film substrate insulated with ceramics or glass is used as the substrate, and a polyimide resin 30 to 90 Vol is used as the adhesive material.
% And fused silica glass powder having an average particle size of 2 μm or less 70 to 10
The multilayer circuit board according to claim 5, wherein a film formed by mixing with Vol% is used. 8. The heat-resistant insulating film is made of polyimide resin 30 to 30.
90% by volume and a coefficient of linear expansion of 3.5 as the main component of quartz
7. The multilayer circuit board according to claim 6, wherein a mixture with an inorganic material powder of ppm / K or less is used. 9. The adhesive is a polyimide resin 30 to 90V.
ol% and the coefficient of linear expansion of quartz as the main component is 3.5 ppm
8. A multi-layer circuit board according to claim 7, wherein a mixture with an inorganic material powder of / K or less is used. 10. The multilayer circuit board according to claim 4, wherein the wiring in the multilayer thin film circuit is a multiple wiring in which another metal film is formed on a part of a copper wiring surface. . 11. The multilayer circuit according to claim 4, wherein the wiring in the multilayer thin film circuit is a multiple wiring in which another metal film is formed on a part of the surface of the gold wiring. substrate. 12. An electronic module having a multi-layer circuit board, an LSI device mounted on the multi-layer circuit board, and a sealing cap for sealing these elements, at least the multi-layer circuit board according to claim 1. An electronic module using one of the multilayer circuit boards. 13. An electronic device in which a large number of electronic elements are incorporated, wherein the electronic module is incorporated by using the electronic module according to claim 12.