JPH09312472A - Multilayer wiring board and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form the diameter of a through-hole precisely in a specific dimen sion by a method wherein the thickness of a thin film wiring conductor is speci fied to exceed 1/2 of the through-hole diameter provided in an organic resin insulating layer also a through-hole is completely filled up with a through-hole conductor. SOLUTION: The thickness of a thin film conductor 3 is specified to exceed 1/2 or a through-hole diameter provided in an organic resin insulating layer 2. Thus, in the case of coating the surface of the organic resin insulating layer 2 with the thin film wiring conductor 3, the through-hole 5 is filled up with a part of the thin film wiring conductor 3 so as to be completely buried in the through-hole 5. Resultantly, in the case of making multulayer wiring by alternately laminating the organic resin layer 2 and the thin film wiring conductor 3, the formation of a stepped part due to the through-hole 5 provided on the organic resin insulating layer 2 arranged beneath the surface of the organic resin insulating film 2 arranged on the upper part can be avoided.

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.

This Mo-Mn method is usually performed with tungsten,
High melting point metal powder such as molybdenum and manganese, organic solvent,
A solvent is added and mixed, and a paste-like metal paste is applied by printing on the outer surface of the green ceramic body in a predetermined pattern by a screen printing method. Then, a plurality of these layers are laminated and fired in a reducing atmosphere to obtain a high melting point. This is a method of sintering and integrating a metal powder and a 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 wiring conductors are formed by a thin-film forming technique is made of glass epoxy formed by impregnating a ceramic cloth made of aluminum oxide sintered body or the like or a glass cloth woven with glass fibers 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 formed by spin coating, thermosetting, or the like, and a metal such as copper or aluminum, a thin film forming technique such as a plating method or a vapor deposition method, and photolithography. It has a structure in which thin film wiring conductors formed by employing the technology are alternately laminated in multiple layers.

Further, in this multilayer wiring board, a through-hole conductor in which the thin-film wiring conductors disposed between the laminated organic resin insulation layers are adhered to the inner walls of the through-holes formed in the organic resin insulation layer are provided. The through holes are formed in each organic resin insulating layer by applying a resist material on each organic resin insulating layer and exposing and developing the resist material so that a predetermined shape is formed at a predetermined position. A window is formed, and then an etchant is placed in the window of the resist material to remove the organic resin insulating layer located in the window of the resist material and form a hole (through hole) in the organic resin insulating layer. Then, finally, the resist material is peeled off from the organic resin insulating layer and removed.

[0009]

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.

In this conventional multilayer wiring board,
The positions of the through holes formed in each organic resin insulating layer are the same, and the through holes are attached to the through holes of the upper organic resin insulating layer and the through holes are attached to the through holes of the lower organic resin insulating layer. When electrically connecting with a conductor, a through hole is formed in the upper organic resin insulating layer by simultaneously removing the organic resin insulating layer filled in the through hole of the lower organic resin insulating layer. It takes a long time to form a through hole, the mass productivity is poor, the multilayer wiring board as a product is expensive, and the diameter of the through hole increases as it goes upward.
It also has a drawback that a through hole having a predetermined size cannot be accurately formed.

[0011]

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 upper and lower thin film wiring conductors are formed in through holes provided in each organic resin insulating layer. A multilayer wiring board formed by connecting via a hole conductor, wherein the thickness of the thin film wiring conductor is ½ or more of the diameter of the through hole provided in the organic resin insulating layer, and the through hole conductor forms the through hole. It is characterized by being completely filled.

The present invention is also the method for manufacturing a multilayer wiring board as described above, wherein (1) an organic resin insulating layer having through holes is formed on the insulating substrate by coating, exposing, and developing a photosensitive organic resin precursor. And (2) 1 for the diameter of the through hole in which copper is formed in the organic resin insulating layer by plating on the upper surface of the organic resin insulating layer having the through hole.
A step of depositing a predetermined pattern to a thickness of ½ or more and at the same time completely filling the through holes with copper,
(3) The steps (1) and (2) are alternately repeated.

Furthermore, the present invention is the above-mentioned method for manufacturing a multilayer wiring board, wherein (1) an organic resin insulating layer having through holes is formed on an insulating substrate by applying an organic resin precursor, heat treatment and perforating. And (2) depositing a predetermined pattern on the upper surface of the organic resin insulating layer having the through holes in a thickness of at least ½ of the diameter of the through holes formed by plating copper on the organic resin insulating layer by plating. And at the same time completely filling the through holes with copper, and (3) repeating the above steps (1) and (2) alternately.

According to the multi-layer wiring board of the present invention, when the thin film wiring conductor is deposited on each organic resin insulating layer, the through hole formed in each organic resin insulating layer is simultaneously filled with the through hole conductor, and the through hole conductor is filled. Since the through-holes were completely filled with the hole conductors, the upper surface of each organic resin insulating layer was almost flat, and as a result, the upper surface of each organic resin insulating layer was formed by using thin film forming technology and photolithography technology. The thin-film wiring conductor does not cause variations in its thickness or breaks, and 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, when the through-hole conductors are filled in the through-holes provided in the organic resin insulating layers, the thin-film wiring conductors are deposited on the upper surfaces of the organic resin insulating layers. Therefore, the manufacturing process of the multilayer wiring board can be made simple and reliable, and the multilayer wiring board as a product can be made inexpensive.

Further, according to the multilayer wiring board of the present invention, the through hole conductor is filled in the through hole provided in each organic resin insulating layer so as to completely fill the through hole. Therefore, when forming a through hole in the organic resin insulating layer located above, it is sufficient to remove the through hole by the thickness of each organic resin insulating layer, the through hole can be formed in a short time, and the multilayer wiring board as a product can be formed. The mass productivity is improved and the diameter of the through hole can be accurately formed to a predetermined size.

[0018]

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 multilayer wiring 4 composed of an organic resin insulating layer 2 and a thin film wiring conductor 3 is arranged, and it functions as a supporting member for supporting the multilayer wiring 4.

The insulating substrate 1 is 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, the organic resin insulating layers 2 and the thin-film wiring conductors 3 are alternately arranged in multiple layers and the multilayer wiring 4 is adhered. The resin insulation layer 2 serves to electrically insulate the thin film wiring conductors 3 located above and below, and the thin film wiring conductor 3 also serves as a transmission path for transmitting an electric signal.

The organic resin insulating layer 2 of the multilayer 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, and is applied to the upper portion of the insulating substrate 1 to a predetermined thickness by using a spin coating method or the like.

The organic resin insulating layer 2 of the multi-layer wiring 4 has through holes 5 formed at respective predetermined positions, and the through holes 5 are thin films located above and below via the organic resin insulating layer 2 described later. It functions as a forming hole for forming the through-hole conductor 6 that electrically connects each of the wiring conductors 3.

Further, a thin film wiring conductor 3 made of copper in a predetermined pattern is formed on the upper surface of the organic resin insulating layer 2, and a through hole conductor 6 made of copper is provided in the through hole 5 provided in each organic resin insulating layer 2. Each of the thin-film wiring conductors 3 is disposed above and below each other, with the organic resin insulating layer 2 sandwiched therebetween by the through-hole conductors 6 so as to be electrically connected.

The thickness of the thin-film wiring conductor 3 is 1/2 or more of the diameter of the through hole 5 provided in the organic resin insulating layer 2, and the thickness of the thin-film wiring conductor 3 is set to the organic resin insulating layer 2.
When the diameter of the through hole 5 provided in the above is set to be 1/2 or more, when the thin film wiring conductor 3 is attached to the upper surface of the organic resin insulating layer 2 by using, for example, an electroless plating method, a part thereof is attached. Are filled in the through holes 5 to completely fill the through holes 5, and as a result, when the organic resin insulating layers 2 and the thin film wiring conductors 3 are alternately laminated to form the multilayer wiring 4, they are arranged on the upper side. There is no step formed on the surface of the organic resin insulating layer 2 due to the through hole 5 provided in the organic resin insulating layer 2 arranged therebelow, and the step is formed on each organic resin insulating layer 2. There is no variation in the thickness of the thin-film wiring conductor 3 and disconnection.

The multilayer wiring 4 formed by alternately arranging the organic resin insulating layers 2 and the thin film wiring conductors 3 in multiple layers has 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.

If the thickness of each of the organic resin insulating layers 2 exceeds 100 μm, it becomes difficult to form the through holes 5 into a desired sharp shape when forming the through holes 5 in the organic resin insulating layer 2. When the thickness is less than 5 μmm, when roughening is performed on the upper surface of the organic resin insulating layer 2 to increase the bonding strength of the organic resin insulating layers 2 located above and below,
There is a risk that unnecessary holes will be formed in the organic resin insulating layer 2 and an unnecessary electrical short circuit will be caused in the thin film wiring conductors 3 located above and below. Therefore, it is preferable that the thickness of each of the organic resin insulating layers 2 is in the range of 5 μm to 100 μm.

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 so that a predetermined electric signal can be 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.

Next, a method of manufacturing the above-mentioned multilayer wiring board will be described with reference to FIG. First, as shown in FIG.
An insulating substrate 1 having a wiring conductor 2a on its upper surface is prepared. The insulating substrate 1 has a glass epoxy resin obtained by impregnating a cloth woven with glass fibers with an epoxy resin, an oxide ceramics such as an aluminum oxide sintered body, a mullite sintered body, or an oxide film on the surface. The wiring conductor 2 is made of an electrically insulating material such as non-oxide ceramics such as an aluminum nitride sintered body and a silicon carbide sintered body. The wiring conductor 2 is formed by etching a thin copper plate adhered to the insulating substrate 1. It is formed by processing into a predetermined pattern, or by printing and coating a metal paste on the insulating substrate 1 by a screen printing method into a predetermined pattern and baking it at a predetermined temperature.

Next, as shown in FIG. 2B, the organic resin insulating layer 2 having the through holes 5 is formed on the insulating substrate 1 having the wiring conductors 2a on the upper surface, and the through holes 5 are wiring conductors of the insulating substrate 1. 2 is formed so as to be positioned on the upper side.

The organic resin insulating layer 2 is made of a photosensitive or thermosetting resin such as an epoxy resin, a polyimide resin, a bismaleimide triazide resin, a polyphenylene ether resin, a fluorine resin, or the like, for example, a photosensitive epoxy resin. In this case, propylene glycol monomethyl ether acetate is added to and mixed with phenol novolac resin, methylol melamine, and diallyl diazonium salt to obtain a paste-like photosensitive epoxy resin precursor, which is applied onto the upper surface of the insulating substrate 1 by a spin coating method or a doctor. The photosensitive epoxy resin precursor is applied to a predetermined thickness by a blade method or the like, and then a predetermined mask is placed on the photosensitive epoxy resin precursor applied to the photosensitive epoxy resin precursor with an exposure machine using a high pressure mercury lamp or the like. irradiation energy 1~3J / cm ³ at a predetermined position Subjected to exposure Te, thereafter, the exposed photosensitive epoxy resin precursor is developed with a spray developing machine,
A hole to be the through hole 5 is formed on the wiring conductor 2a, and this is heated at a temperature of 180 ° C. for 30 to 60 minutes,
When it is formed by completely curing and is made of a thermosetting epoxy resin, a bisphenol A type epoxy resin, a novolac type epoxy resin, a glycidyl ester type epoxy resin or the like is added to an amine type curing agent, an imidazole type curing agent, A curing agent such as an acid anhydride curing agent is added and mixed to obtain a pasty epoxy resin precursor, and the epoxy resin precursor is applied onto the insulating substrate 1 having the wiring conductor 2a on the upper surface by spin coating or the like. Then, this is heat-treated at a temperature of 80 ° C. to 200 ° C. for 0.5 to 3 hours to be thermoset, and a hole is formed on the wiring conductor 2a by a YAG laser, an excimer laser or the like to form a through hole 5. Formed by.

Then, as shown in FIG. 2C, the thin film wiring conductor 2 is filled on the upper surface of the organic resin insulating layer 2, and the through hole conductor 6 is filled in the through hole 5 formed in the organic resin insulating layer 2. . The thin film wiring conductor 3 and the through hole conductor 6 formed and filled in the upper surface of the organic resin insulating layer 2 and the through hole 5 are made of copper, for example, electroless plating, specifically, the organic resin insulation having the through hole 5. The insulating substrate 1 having the layer 2 deposited thereon is treated with copper sulfate 0.06 mol / liter,
Formalin 0.3 mol / l, sodium hydroxide 0.35 mol / l, ethylenediaminetetraacetic acid 0.
The copper layer is deposited on the upper surface of the organic resin insulating layer 2 and the inside of the through hole 5 by immersing it in an electroless plating bath of 35 mol / liter, and then deposited on the upper surface of the organic resin insulating layer 2. The formed copper layer is formed into a predetermined pattern by photolithography. In this case, since the thin-film wiring conductor 3 is formed by a thin-film forming technique, the wiring can be miniaturized, whereby the thin-film wiring conductor 3 can be formed at an extremely high density.

The thickness of the thin film wiring conductor 3 deposited on the upper surface of the organic resin insulating layer 2 is set to be 1/2 or more of the diameter of the through hole 5 formed in the organic resin insulating layer 2. A through hole conductor 6 made of copper is deposited inside the through hole 5 provided in the organic resin insulating layer 2 when the thin film wiring conductor 3 is deposited on the upper surface of the organic resin insulating layer 2 by electroless plating. However, at the same time, the through hole 5 is completely filled, and the manufacturing process of the multilayer wiring board is simple and reliable, and the multilayer wiring board as a product can be made inexpensive.

If the organic resin insulating layer 2 and the thin film wiring conductor 3 are alternately formed, the organic resin insulating layer 2 and the thin film wiring conductor 3 are alternately laminated on the upper surface of the insulating substrate 1 shown in FIG. At the same time, a multilayer wiring board as a product is completed in which the thin film wiring conductors located above and below are connected via the through-hole conductors formed in the through-holes provided in each organic resin insulating layer.

The organic resin insulation layer 2 is formed on the insulation substrate 1.
When the thin film wiring conductors 3 and the thin film wiring conductors 3 are alternately laminated, even if the through holes 5 formed in each organic resin insulating layer 2 are at the same position, the through holes 5 should be completely filled in each through hole 5. Since the through hole conductor 6 is filled in the organic resin insulating layer 2 located above, the through hole 5 is formed.
When forming the through holes 5, the through holes 5 are formed in the organic resin insulating layer 2
It is sufficient to remove only the thickness of the through hole 5, the through hole 5 can be formed in a short time, the mass productivity of the multilayer wiring board as a product can be improved, and the diameter of the through hole can be accurately formed to a predetermined size. .

The present invention is not limited to the above-mentioned embodiments, but 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. Although the through-hole conductor 6 is formed by the electroless plating method, it is not limited to this and may be formed by using both the electroless plating method and the electrolytic plating method.

[0037]

According to the multilayer wiring board of the present invention, when the thin film wiring conductor is deposited on each organic resin insulating layer, the through holes provided in each organic resin insulating layer are simultaneously filled with the through hole conductors. Since the through hole is completely filled with the through hole conductor, the upper surface of each organic resin insulating layer becomes substantially flat, and as a result, the thin film forming technology and the photolithography technology are applied to the upper surface of each organic resin insulating layer. The thin-film wiring conductor formed does not cause variations in thickness or disconnection, and it is possible to fully exhibit the desired characteristics of the multilayer wiring board.

According to the multilayer wiring board of the present invention, the filling of the through-hole conductor into the through-hole provided in each of the organic resin insulating layers is performed when the thin film wiring conductor is deposited on the upper surface of each organic resin insulating layer. Therefore, the manufacturing process of the multilayer wiring board can be made simple and reliable, and the multilayer wiring board as a product can be made inexpensive.

Further, according to the multilayer wiring board of the present invention, the through hole conductor is filled in the through hole provided in each organic resin insulating layer so as to completely fill the through hole. Therefore, when forming a through hole in the organic resin insulating layer located above, it is sufficient to remove the through hole by the thickness of each organic resin insulating layer, the through hole can be formed in a short time, and the multilayer wiring board as a product can be formed. The mass productivity is improved and the diameter of the through hole can be accurately formed to a predetermined size.

[Brief description of drawings]

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

2 (a), (b) and (c) are cross-sectional views for each step for explaining the method for manufacturing a multilayer wiring board according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Insulating board 2 ... Organic resin insulating layer 3 ... Thin film wiring conductor 4 ... Multilayer wiring 5 ... Through-hole 6 ... Through-hole conductor

Claims (3)

[Claims] 1. A through-hole conductor in which an organic resin insulating layer and a thin film wiring conductor are alternately laminated on an insulating substrate and upper and lower thin film wiring conductors are formed in through holes provided in each organic resin insulating layer. A thin film wiring conductor having a thickness of ½ or more of a diameter of a through hole provided in an organic resin insulation layer, and the through hole conductor completely covers the through hole. A multilayer wiring board characterized by being filled. 2. A step of (1) forming an organic resin insulating layer having a through hole by coating, exposing and developing a photosensitive organic resin precursor on an insulating substrate, and (2) an organic resin having the through hole. A step of depositing copper on the upper surface of the insulating layer by a plating method in a predetermined pattern to a thickness of ½ or more of the diameter of the through hole formed in the organic resin insulating layer, and at the same time completely filling the through hole with copper; When,
(3) A method for manufacturing a multilayer wiring board, which comprises the steps of alternately repeating the steps (1) and (2). 3. A step (1) of forming an organic resin insulating layer having a through hole on an insulating substrate by coating an organic resin precursor, heat treatment, and punching, and (2) an organic resin having the through hole. A step of depositing copper on the upper surface of the insulating layer by a plating method so as to have a thickness of 1/2 or more of the diameter of the through hole formed in the organic resin insulating layer and at the same time completely filling the through hole with copper. When,
(3) A method for manufacturing a multilayer wiring board, which comprises the steps of alternately repeating the steps (1) and (2).