JPH09289375A - Multilayer wiring board - Google Patents

Abstract

(57) Abstract: A disconnection occurs in a thin film wiring conductor due to a step formed on an upper surface of an organic resin insulating layer. SOLUTION: An inner wall of a through hole 5 in which organic resin insulation layers 2 and thin film wiring conductors 3 are alternately laminated on an insulating substrate 1 and upper and lower thin film wiring conductors 3 are provided in each organic resin insulation layer 2 A multi-layer wiring board formed by connecting via through-hole conductors 6 attached to the organic resin insulating layer 2 and having an upper surface in each through hole 5 of each organic resin insulating layer 2.
Was filled with a filling material 7 that was substantially the same as the upper surface.

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, in a multilayer wiring board used for a hybrid integrated circuit device, a package for housing a semiconductor element, etc., its wiring conductor is formed by a thick film forming technique such as Mo--Mn method.

The Mo-M method is usually a screen-printing method in which a high-melting metal powder of tungsten, molybdenum, manganese or the like is mixed with an organic solvent and a solvent to form a paste-like metal paste on the outer surface of the green ceramic body. Is applied in a predetermined pattern by printing, and then a plurality of these are laminated and fired in a reducing atmosphere to sinter and integrate the high melting point metal powder and the green ceramic body.

Incidentally, the ceramic body on which the wiring conductor is formed is usually an oxide ceramic such as an aluminum oxide sintered body or a mullite sintered body, or an aluminum nitride having an oxide film adhered on the surface. Non-oxide ceramics such as a sintered compact or a silicon carbide sintered compact are used.

However, when the wiring conductor is formed by using this Mo-Mn method, the wiring conductor is formed by screen-printing a metal paste. Therefore, it is difficult to miniaturize the wiring conductor and the wiring conductor can be formed at a high density. It had the drawback of not being able to.

In order to solve the above-mentioned drawbacks, therefore, a multilayer wiring board is used which is formed at a high density by using a thin film forming technique capable of miniaturization instead of forming the wiring conductor by a conventional thick film forming technique. It's starting to happen.

A multilayer wiring board in which such a wiring conductor is formed by a thin film forming technique is made of glass epoxy or the like formed by impregnating a ceramic made of an aluminum oxide sintered body or the like or a glass cloth woven glass cloth with an epoxy resin. An insulating layer made of an organic resin such as an epoxy resin formed on the upper surface of an insulating substrate by a spin coating method or a thermosetting process, and a thin film forming technique such as an electroless plating method or a vapor deposition method for a metal such as copper or aluminum; Through which thin film wiring conductors formed by adopting photolithography technology are alternately arranged in multiple layers and upper and lower thin film wiring conductors are attached to the inner wall of the through hole provided in the organic resin insulation layer. It has a structure in which it is electrically connected through a hole conductor.

[0008]

However, in this conventional multilayer wiring board, when the organic resin insulating layers and the thin film wiring conductors are alternately laminated to form a multilayer wiring board, the organic resin insulating layer disposed on the upper side is arranged. A step is formed on the surface of the layer due to a through hole provided in the organic resin insulating layer disposed below, and the step is formed by adopting a thin film forming technique and a photolithography technique on each organic resin insulating layer. The thin film wiring conductor thus produced has variations in thickness and wire breakage, and thus has a drawback that the desired characteristics as a multilayer wiring board cannot be sufficiently exhibited.

[0009]

SUMMARY OF THE INVENTION The present invention has been devised in view of the above-mentioned drawbacks, and an object thereof is to provide a multilayer wiring board in which organic resin insulating layers and thin film wiring conductors are alternately laminated in multiple layers. Another object of the present invention is to provide a multilayer wiring board which can effectively prevent thickness variation and disconnection of the thin film wiring conductor, and thereby can sufficiently exhibit desired characteristics.

According to the present invention, an organic resin insulating layer and a thin film wiring conductor are alternately laminated on an insulating substrate, and thin film wiring conductors located above and below are adhered to the inner wall of a through hole provided in each organic resin insulating layer. A multi-layer wiring board formed by connecting via through-hole conductors, the upper surface of which is substantially the same as the upper surface of each organic resin insulating layer in the through hole of each organic resin insulating layer. It is characterized by having done.

Further, the present invention is characterized in that the filling is made of a plated metal deposited on the surface of the through-hole conductor.

According to the multilayer wiring board of the present invention, the filling is filled in the through holes provided in each organic resin insulating layer and the upper surface of each organic resin insulating layer is made flat. When a thin film wiring conductor is formed by adopting thin film forming technology and photolithography technology on the upper surface, there is no variation in thickness or disconnection in the formed thin film wiring conductor, and as a result, the desired characteristics of the multilayer wiring board are obtained. It becomes possible to fully demonstrate.

Further, according to the multilayer wiring board of the present invention, the filling material filled in the through holes provided in each of the organic resin insulating layers is formed by the plated metal deposited on the surface of the through hole conductor. If so, the filling of the filling material into the through hole becomes reliable and easy.

[0014]

Next, the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows an embodiment of a multilayer wiring board according to the present invention, wherein 1 is an insulating substrate, 2 is an organic resin insulating layer, and 3 is a thin film wiring conductor.

On the upper surface of the insulating substrate 1, a multi-layer wiring 4 composed of an organic resin insulating layer 2 and a thin-film wiring conductor 3 is disposed, and functions as a support member for supporting the multi-layer wiring 4.

The insulating substrate 1 is made of an oxide ceramic such as an aluminum oxide sintered body or a mullite sintered body, or an aluminum nitride sintered body having an oxide film on its surface.
It is made of a non-oxide ceramic such as a silicon carbide sintered body, and an electrically insulating material such as a glass epoxy resin obtained by impregnating a cloth woven with glass fiber with an epoxy resin. For example, an aluminum oxide sintered body. In the case of being formed of, alumina (Al ₂ O ₃ ) and silica (Si
O ₂ ), calcia (CaO), magnesia (MgO), and other raw material powders are mixed with an appropriate organic solvent and solvent to form a slurry, which is then applied by the well-known doctor blade method or calendar roll method. To form a ceramic green sheet (ceramic green sheet), and then subject the ceramic green sheet to an appropriate punching process to form a predetermined shape and a high temperature (about 160).
(0 ° C.) or by mixing a raw material powder such as alumina with an appropriate organic solvent and solvent to prepare the raw material powder, and molding the raw material powder into a predetermined shape by a press molding machine, and finally It is manufactured by firing the molded body at a temperature of about 1600 ° C.

On the upper surface of the insulating substrate 1, an organic resin insulating layer 2 and thin film wiring conductors 3 are alternately arranged in multiple layers and a multilayer wiring 4 is attached. The resin insulating layer 2 functions to electrically insulate the thin film wiring conductors 3 positioned above and below, and the thin film wiring conductor 3 functions as a transmission path for transmitting an electric signal.

The organic resin insulation layer 2 of the multi-layer wiring 4 is made of a resin such as an epoxy resin, a polyimide resin, a bismaleimide polyazide resin, a polyphenylene ether resin or a fluorine resin. For example, when it is made of an epoxy resin, it is a bisphenol A type. Along with the epoxy resin, novolac type epoxy resin, glycidyl ester type epoxy resin, etc., a curing agent such as an amine curing agent, an imidazole curing agent, an acid anhydride curing agent is added and mixed to obtain a pasty epoxy resin precursor. The epoxy resin precursor is applied to the upper part of the insulating substrate 1 by spin coating, and then heat-treated at 80 ° C. to 200 ° C. for 0.5 to 3 hours,
It is formed by thermosetting.

Further, the organic resin insulating layer 2 of the multi-layer wiring 4 has through holes 5 each having a minimum diameter of about 1.5 times the thickness of the organic resin insulating layer 2 at a predetermined position thereof. The through hole 5 functions as a forming hole for forming a through hole conductor 6 that electrically connects each of the thin film wiring conductors 3 located above and below via the organic resin insulating layer 2 described later.

The through hole 5 provided in the organic resin insulating layer 2 is formed in the organic resin insulating layer 2 to have a predetermined diameter by adopting a conventionally known photolithography technique.

A thin-film wiring conductor 3 having a predetermined pattern is provided on the upper surface of each organic resin insulating layer 2, and a through-hole conductor 6 is provided on the inner wall of a through hole 5 provided in each organic resin insulating layer 2. Each of the thin-film wiring conductors 3 located above and below the organic resin insulating layer 2 with the through-hole conductor 6 interposed therebetween is electrically connected.

The thin-film wiring conductors 3 and the through-hole conductors 6 provided on the upper surface of each organic resin insulating layer 2 and the inner wall of the through-hole 5 are made of a metal material such as copper, nickel, gold or aluminum by an electroless plating method. It is formed by adopting a thin film forming technique such as a vapor deposition method and a sputtering method and an etching processing technique. For example, when it is made of copper, copper sulfate is formed on the upper surface of the organic resin insulating layer 2 and the inner surface of the through hole 5. 0.06 mol / l, formalin 0.3
Mol / liter, sodium hydroxide 0.35 mol / liter, ethylenediaminetetraacetic acid 0.35 mol / liter, using an electroless plating bath, thickness of 1 μm to 40 μ
m copper layers are deposited, and then the copper layers are processed into a predetermined pattern by an etching processing method so as to be disposed between the organic resin insulating layers 2. In this case, since the thin-film wiring conductor 3 and the through-hole conductor 6 are formed by a thin-film forming technique, the wiring can be miniaturized, and thereby the thin-film wiring conductor 3 can be formed at an extremely high density.

The multi-layer wiring 4 formed by alternately arranging the organic resin insulating layers 2 and the thin film wiring conductors 3 in multiple layers forms the center line average roughness (Ra) on the upper surface of each organic resin insulating layer 2. With a rough surface of 0.05 μm ≦ Ra ≦ 5 μm, the organic resin insulating layer 2 and the thin film wiring conductor 3 can be joined firmly and the organic resin insulating layers 2 located above and below can be firmly joined. Therefore, it is preferable that the upper surface of each organic resin insulating layer 2 of the multilayer wiring 4 is roughened by an etching method or the like so that the center line average roughness (Ra) is a rough surface of 0.05 μm ≦ Ra ≦ 5 μm.

When the thickness of each of the organic resin insulating layers 2 exceeds 100 μm, the through holes 5 are formed by applying the photolithography technique to the organic resin insulating layer 2.
When forming, the etching processing time becomes long and it becomes difficult to form the through hole 5 into a desired and clear shape, and when it is less than 5 μm, the organic resin insulating layers located above and below the organic resin insulating layer 2 are formed. There is a risk that unnecessary holes will be formed in the organic resin insulation layer 2 and unnecessary electrical shorts will be caused in the upper and lower thin film wiring conductors 3 when roughening is performed to increase the bonding strength of the second resin. . Therefore, the organic resin insulating layer 2 has a thickness of 5 μm to 100 μm.
It is preferable to set it in the range of m.

Further, when the thickness of each thin film wiring conductor 3 of the multi-layer wiring 4 is less than 1 μm, the electric resistance of each thin film wiring conductor 3 becomes large and a predetermined electric signal is transmitted to each thin film wiring conductor 3. Becomes difficult, and again 40
If the thickness exceeds μm, a large stress is present inside the thin film wiring conductor 3 when the thin film wiring conductor 3 is applied to the organic resin insulating layer 2, and the thin film wiring conductor 3 is separated from the organic resin insulating layer 2 by the large intrinsic stress. It is easy to do. Therefore, the thickness of each thin film wiring conductor 3 of the multilayer wiring 4 is 1 μm to 40 μm.
It is preferable to set it in the range of m.

Further, each organic resin insulating layer 2 of the multi-layer wiring 4 has a through hole 5 provided in each of them so that a filling material 7 has its upper surface substantially the same as the upper surface of each organic resin insulating layer 2. It is filled with.

The filler 7 acts to make the upper surface of each organic resin insulating layer 2 flat without a large step, and thus a thin film forming technique and a photolithography technique are applied to the upper surface of each organic resin insulating layer 2. When the thin-film wiring conductor 3 is formed, the thin-film wiring conductor 3 to be formed has a uniform thickness and does not cause disconnection. As a result, the multilayer wiring board can sufficiently exhibit desired characteristics. It will be possible.

The filler 7 is made of, for example, a metal material, and the upper surface of the filler 7 is substantially the same as the upper surface of each organic resin insulating layer 2 in the through holes 5 provided in each organic resin insulating layer 2 by printing or plating. To be filled.

If the filling 7 is formed of a plated metal that is deposited on the surface of the through-hole conductor 6 by a plating method, the filling of the filling 7 into the through-hole 5 will be reliable and easy. . Therefore, considering the workability of the filling of the filling material 7, the filling material 7 can be used as the through-hole conductor 6.
It is preferable to form a plated metal on the surface of the plate by a plating method.

The present invention is not limited to the above-mentioned embodiments, and various modifications can be made without departing from the scope of the present invention. For example, in the above-mentioned embodiments, the thin film wiring conductor 3 is used. If the thickness is small, the upper surface of the filler 7 may be slightly projected from the upper surface of the organic resin insulating layer 2 so as to be the same as the upper surface of the thin film wiring conductor 3.

[0031]

According to the multilayer wiring board of the present invention, the filling is filled in the through holes provided in each organic resin insulating layer,
When the thin film wiring conductor is formed by adopting the thin film forming technology and the photolithography technology on the upper surface of each organic resin insulating layer because the upper surface of each organic resin insulating layer is made flat, There is no variation or disconnection, and as a result, it is possible to fully exhibit the desired characteristics of the multilayer wiring board.

Further, according to the multilayer wiring board of the present invention, the filling material filled in the through holes provided in each of the organic resin insulating layers is formed by the plated metal deposited on the surface of the through hole conductor. If so, the filling of the filling material into the through hole becomes reliable and easy.

[Brief description of drawings]

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Insulating substrate 2 ... Organic resin insulating layer 3 ... Thin film wiring conductor 4 ... Multilayer wiring 5 ... Through hole 6 ... Through hole conductor 7 ... Filling material

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location H05K 3/24 H01L 23/12 N

Claims (2)

[Claims] 1. An organic resin insulating layer and a thin film wiring conductor are alternately laminated on an insulating substrate, and the upper and lower thin film wiring conductors are attached to the inner walls of through holes provided in each organic resin insulating layer. A multilayer wiring board formed by connecting through through-hole conductors, wherein a filling material having an upper surface substantially the same as the upper surface of each organic resin insulating layer is filled in the through hole of each organic resin insulating layer. A multilayer wiring board characterized by the above. 2. The multilayer wiring board according to claim 1, wherein the filling material is a plated metal deposited on the surface of the through-hole conductor.