JP2002252462A - Multilayer wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem raised by a multilayer wiring board in which an insulating layer composed of a plurality of insulating film layers is formed on a substrate that via-hole conductors are deformed and a disconnection occurs when the insulating film layers are heated and pressed for laminating the film layer by sticking the layer to each other. SOLUTION: The multilayer wiring board is constituted by alternately laminating a plurality of insulating film layers 4 and a plurality of wiring conductor layers 3 by sticking the layers 4 and 3 to each other via thermoplastic insulating adhesive layers 5 interposed between the film layers 4, and by electrically connecting upper and lower wiring conductor layers 3 to each other thorough via-hole conductors 7 provided in via holes 6 made through the film layers 4. The occupation ratio of the opening areas of the via-hole holes 6 to the areas of the film layers 4 are adjusted to >=0.1%. Consequently, the pressures applied to the via-hole conductors 7 can be lowered in a scattered state, and the disconnection of the conductors 7 caused by the deformation of the conductor 7 can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer wiring board, and more particularly to a multilayer wiring board used for a hybrid integrated circuit device, a semiconductor element housing package for housing a semiconductor element, and the like.

[0002]

2. Description of the Related Art Conventionally, as a multilayer wiring board used for a hybrid integrated circuit device, a package for housing a semiconductor element, and the like,
For the purpose of forming wiring conductors at a high density, a multilayer wiring board having a multilayer wiring portion formed of a thin insulating layer and a wiring conductor layer formed on a substrate has been employed.

[0003] Such a multilayer wiring board is composed of a thin insulating layer made of a polyimide resin or the like formed by a spin coating method or the like and a metal made of a metal such as copper or aluminum on the upper surface of a substrate made of an aluminum oxide sintered body or the like. And a wiring conductor layer formed by employing a thin film forming technique such as a sputtering method, a vapor deposition method, and a plating method, and a photolithography technique.

However, when an insulating layer made of a polyimide resin is formed by a spin coating method, a polyimide resin precursor is applied in a number of steps to form an insulating layer having a desired thickness. Since a curing step for polyimide is required, the production process becomes longer.

Therefore, a multilayer wiring board using an insulating layer formed by laminating a plurality of insulating film layers made of a polyimide resin or the like via an insulating adhesive layer made of a bismaleimide triazine resin or the like has been adopted.

In order to form the insulating layer of such a multilayer wiring board, first, an insulating film is prepared by applying an insulating adhesive to the insulating film by using a doctor blade method or the like, and then drying the insulating film layer. This is performed by stacking an insulating adhesive layer on the upper surface of the film layer so as to be disposed therebetween, and by applying heat and pressure using a heating press device to bond the layers.

In order to electrically connect the upper and lower wiring conductor layers, via holes are formed in the insulating film layer and the insulating adhesive layer by a technique such as laser or dry etching.
After that, sputtering method, evaporation method,
This is performed by forming a via-hole conductor with a substantially uniform thickness by employing a thin film forming technique such as a plating method and a photolithography technique.

[0008]

However, in a multilayer wiring board in which the above-described insulating film layer is heated and pressed through a thermoplastic insulating adhesive layer, the heating and pressing during laminating and bonding are performed by heat. Above the glass transition temperature at which the plastic insulating adhesive layer is sufficiently softened, a pressure greater than the elastic modulus of the insulating adhesive layer is applied. Because the thermoplastic insulating adhesive layer in the insulating layer softens and flows, more pressure is concentrated on the via hole conductor, and the via hole conductor formed on the inner wall of the via hole may be deformed and broken . Therefore, there is a problem that a conduction failure of the via-hole conductor occurs due to this.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems in the prior art, and has as its object to suppress the deformation of via-hole conductors generated when laminating and bonding insulating film layers, and to provide a multilayer having excellent electrical connection reliability. It is to provide a wiring board.

[0010]

According to the present invention, there is provided a multilayer wiring board comprising a plurality of insulating film layers made of an organic resin and a plurality of wiring conductor layers on a substrate, and a thermoplastic insulating adhesive layer between the insulating film layers. A multi-layer wiring board comprising a plurality of wiring layers which are laminated and adhered through each other, and wherein the wiring conductor layers located above and below are electrically connected to each other by arranging via-hole conductors in via holes provided in the insulating film layer, The occupation ratio of the opening area of the via hole to the area of the insulating film layer is 0.1% or more.

According to the multilayer wiring board of the present invention, the occupation ratio of the opening area of the via hole to the area of the insulating film layer is 0.1%.
Since it is 1% or more, the thermoplastic insulating adhesive layer in the lower insulating layer softens and flows due to the heating and pressurization when laminating and bonding the upper insulating film layer, but the pressure is applied to each via hole conductor. Since the via hole conductor is dispersed and held, deformation of the via hole conductor in the lower insulating layer is suppressed, so that the via hole conductor is not deformed and broken, and no conduction failure of the via hole conductor occurs.

Thus, a multilayer wiring board having excellent electrical connection reliability can be obtained.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings.

FIG. 1 is a cross-sectional view showing an embodiment of a multilayer wiring board according to the present invention. In FIG.
2 is a multilayer wiring portion, 3 is a wiring conductor layer, 4 is an insulating film layer, 5 is an insulating adhesive layer, 6 is a via hole, and 7 is a via hole conductor.

The substrate 1 is provided with a multilayer wiring portion 2 in which a plurality of insulating film layers 4 each having a conductor layer 3 formed on the upper surface thereof are adhered to each other with an insulating adhesive layer 5 and laminated in multiple layers. It functions as a support member for supporting the multilayer wiring section 2.

The substrate 1 is made of an oxide ceramic such as an aluminum oxide sintered body or a mullite sintered body, or a non-oxide ceramic such as an aluminum nitride sintered body or a silicon carbide sintered body having an oxide film on its surface. It is formed of an electrically insulating material such as an oxide ceramic, a glass epoxy resin in which a glass fiber base material is impregnated with an epoxy resin, or a glass fiber base material in which a bismaleimide triazine resin is impregnated. .

For example, in the case of being formed of an aluminum oxide sintered body, an appropriate organic solvent / solvent is added to a raw material powder such as alumina / silica / calcia / magnesia and mixed to form a slurry. A ceramic green sheet (ceramic green sheet) is formed by employing a conventionally known doctor blade method or calender roll method. Thereafter, the ceramic green sheet is subjected to an appropriate punching process to obtain a predetermined shape and a high temperature (approximately). 1600 ° C) or by mixing an appropriate organic solvent / solvent with the raw material powder such as alumina to prepare the raw material powder and forming the raw material powder into a predetermined shape by a press molding machine. It is manufactured by firing a molded body at a high temperature (about 1600 ° C.). In the case of a glass epoxy resin, for example, a substrate made of glass fiber is impregnated with an epoxy resin precursor,
The epoxy resin precursor is manufactured by thermosetting at a predetermined temperature.

The conductor layer 3 of the multilayer wiring section 2 provided on the upper surface of the substrate 1 functions as a transmission path for transmitting electric signals, and the insulating film layer 4 electrically connects the wiring conductor layers 3 positioned above and below. It has the function of electrically insulating.

The insulating layer of the multilayer wiring section 2 is an insulating film layer 4
And an insulating adhesive layer 5, the insulating film layer 4
Is polyimide resin, polyphenylene sulfide resin,
Consists of wholly aromatic polyester resin, fluororesin, etc. The insulating adhesive layer 5 is made of polyphenylene ether resin.
It is made of a thermoplastic resin such as polyimide siloxane resin and fluorine resin.

The insulating layer is formed by first applying an insulating adhesive to an insulating film of about 12.5 to 50 μm to a dry thickness of about 5 to 20 μm using a doctor blade method or the like and preparing a dried one. The insulating film layer 4 is stacked on the upper surface of the substrate 1 or the lower insulating film layer 4 so that the insulating adhesive layer 5 is arranged, and the insulating adhesive layer 5 is heated and pressed using a heating press device to be bonded.

A via hole 6 is formed in the insulating layer, and a via hole conductor 7 is formed on the inner wall of the via hole 6 to electrically connect each of the wiring conductor layers 3 positioned above and below the insulating film layer 4. A connection path is formed for the connection.

The via hole 6 is formed by removing a part of the insulating film layer 4 and the insulating adhesive layer 5 using, for example, a laser. In particular, when the opening diameter of the via hole 6 is small, it is desirable to form the via hole 6 with an ultraviolet laser that facilitates control of the shape of the via hole 6 and smoothly processes the inner wall surface of the via hole 6.

The present inventor believes that the thermoplastic insulating adhesive layer 5 in the lower insulating layer is softened by heating and pressing when the insulating film layer 4 is laminated and bonded, and the via-hole conductor 7 in the lower insulating layer is softened. As a result of repeating various studies and experiments on the relationship between the deformation of the insulating film layer and the occupation ratio of the opening area of the via hole 6 to the area of the insulating film layer 4,
Occupation ratio of opening area of via hole 6 is 0.1%
When the thickness is smaller, the thermoplastic insulating adhesive layer 5 in the lower insulating layer is softened and flows due to the heating and pressurizing when the upper insulating film layer 4 is laminated and bonded. Since more pressure is concentrated, it has been found that the via hole conductor 7 formed on the inner wall of the via hole 6 tends to be deformed and easily broken. As a result, by setting the occupation ratio of the opening area of the via hole 6 to the area of the insulating film layer 4 to 0.1% or more, the via hole conductor 7 generated at the time of laminating and bonding the insulating film layer 4 is formed.
And a multilayer wiring board having excellent electrical connection reliability has been completed.

On the other hand, if the occupation ratio of the opening area of the via hole 6 to the area of the insulating film layer 4 is increased, the thermoplastic resin existing in the lower insulating layer is heated and pressed when the upper insulating film layer 4 is laminated and bonded. The insulating adhesive layer 5 softens and flows, but the pressure is efficiently dispersed in the via-hole conductors 7 and can be sufficiently maintained. For this reason, the deformation of the via-hole conductor 7 due to the pressure is better suppressed. However, if the occupation ratio of the opening area of the via hole 6 to the area of the insulating film layer 4 becomes too high, the distance between the adjacent via hole conductors 7 becomes extremely close. The via-hole conductors 7 to be short-circuited. For example, when the occupation ratio of the opening area of the via hole 6 to the area of the insulating film layer 4 is 50% and the diameter of the via hole 6 is 20 μm, the distance between the adjacent via holes 6 is about 5 μm even if the via holes 6 are evenly arranged. And the via-hole conductor 7 is 3
Even if it is bent and deformed by about μm, adjacent via-hole conductors 7 are short-circuited. Therefore, from the viewpoint of suppressing the short circuit of the adjacent via-hole conductor 7, the insulating film layer 4
It is preferable that the occupation ratio of the opening area of the via hole 6 is lower than 50% of the area.

In particular, if the occupation ratio of the opening area of the via hole 6 to the area of the insulating film layer 4 is set to 20% or less,
Since the distance between the adjacent via holes 6 is equal to the diameter of the via hole 6, even if the via hole conductor 7 is slightly deformed by heating and pressing when the upper insulating film layer 4 is laminated and bonded, the adjacent via hole conductor 7 No short circuit occurs between them. For this reason, the occupation ratio of the opening area of the via hole 6 to the area of the insulating film layer 4 is preferably set to 20% or less.

In order to efficiently disperse the pressure at the time of laminating and bonding the upper insulating film layer 4 to the via-hole conductors 7, for example, the via holes 6 are not arranged so as to be unevenly distributed in a part. It is preferable to arrange them so as to be substantially even on the grid intersections. However, there is no problem in arranging the via holes 6 approximately uniformly and then partially arranging the via holes 6 in a required location.

The wiring conductor layer 3 and the via hole conductor 7 are made of copper, gold, aluminum, nickel, chromium, molybdenum,
A metal material such as titanium or an alloy thereof is formed by employing a thin film forming technique such as a sputtering method, a vapor deposition method, or a plating method and a photolithography technique.

The via-hole conductor 7 may be formed separately from the wiring conductor layer 3. However, when these are formed at the same time, the number of steps can be reduced and the electrical connection reliability between the two is good.

It is preferable that the via-hole conductor 7 is formed of copper or an alloy containing copper as a main component in terms of electric conductivity and elastic modulus. In particular, when an alloy containing copper as a main component and a small amount of chromium is added to the via-hole conductor 7, the elastic modulus of copper is kept high up to a high temperature. 7 is better suppressed.

The method of forming the wiring conductor layer 3 and the via-hole conductor 7 is, for example, a method in which chromium, molybdenum, titanium or the like as a diffusion prevention layer (barrier layer) is formed on a large area mainly composed of copper and on at least one main surface of the copper layer. To form a conductor layer. Next, a photoresist is formed in a desired pattern thereon, and unnecessary portions of the conductor layer are removed by etching using the photoresist as a mask, whereby the conductor layer is processed into a desired pattern. The uppermost wiring conductor layer 3 of the insulating film layer 4 has a nickel layer and a gold layer formed by plating on the copper layer for the wiring conductor layer 3 from the viewpoint of chip component mounting and environmental resistance. Good to do.

Thus, according to the multi-layer wiring board of the present invention, the multi-layer wiring board is used for a hybrid integrated circuit device, a semiconductor element housing package for housing a semiconductor element, and the like. Electronic components such as semiconductor elements, capacitance elements, and resistors are mounted and mounted, and each electrode of the electronic components is electrically connected to the wiring conductor layer 3 to be used as a semiconductor device or an electronic device.

The present invention is not limited to the above-described example, and various modifications can be made without departing from the gist of the present invention.

For example, all of the via-hole conductors 7 do not necessarily have to electrically connect each of the wiring conductor layers 3 located above and below, and disperse the pressure at the time of laminating and bonding the upper insulating film layer 4. Some may be formed as support members only for the purpose.

[0034]

As described above, according to the multilayer wiring board of the present invention, since the occupation ratio of the opening area of the via hole to the area of the insulating film layer is set to 0.1% or more, the upper insulating film layer is laminated. The thermoplastic insulating adhesive layer in the lower insulating layer softens and flows due to the heating and pressing at the time of bonding, but since the pressure is dispersed and held in each via hole conductor, the pressure of the via hole conductor in the lower insulating layer is reduced. Deformation is suppressed, so that the via-hole conductor is not deformed and broken, and the conduction failure of the via-hole conductor does not occur.

As a result, a multilayer wiring board having excellent electrical connection reliability can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of an embodiment of a multilayer wiring board of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Substrate 2 ... Multilayer wiring part 3 ... Wiring conductor layer 4 ... Insulating film layer 5 ... Insulating adhesive layer 6 ... Via hole 7 ...・ Via hole conductor

Continued on the front page F-term (reference) 5E317 AA24 BB01 BB02 BB03 BB04 BB11 BB12 BB13 BB14 BB15 BB16 CC13 CC25 CC31 CC51 CD25 CD27 CD32 GG05 GG09 5E346 AA43 CC04 CC08 CC09 CC10 CC14 CC16 CC17 CC19 CC16 EE08 EE12 EE33 EE35 FF05 FF07 FF09 FF10 FF17 GG15 GG28 HH07 HH11

Claims (1)

[Claims] 1. A plurality of insulating film layers made of an organic resin and a plurality of wiring conductor layers are laminated and adhered in layers on a substrate via a thermoplastic insulating adhesive layer between the insulating film layers. What is claimed is: 1. A multilayer wiring board comprising a via hole conductor disposed in a via hole provided in said insulating film layer and electrically connecting said wiring conductor layers to each other, wherein an opening area of said via hole with respect to an area of said insulating film layer Characterized by having an occupancy of 0.1% or more.