JPH0951169A - Resist material with improved adhesiveness and printed circuit board having insulating layer formed therefrom - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resist material with improved adhesiveness and to provide a printed circuit board with improved adhesiveness using it. SOLUTION: A resist material containing fine grains is spread on a board, and the fine grains in the resist layer surface is removed chemically and/or physically before and/or after hardening to provide fine recesses on the resist layer surface, and further, electrically conductive layers and/or other insulating layers are repeatedly provided on the resist layer surface for building up. Electrically conductive layers and/or other insulating layers are sequentially and repeatedly built up on an insulating layer, having fine recesses on its surface, formed from this resist material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photoresist or a non-photosensitive resist which serves as an insulating layer of a multilayer circuit board such as a printed wiring board and a semiconductor substrate, and a wiring board using the same. In particular, when it is used as an insulating layer of a build-up type circuit board, it exhibits excellent adhesiveness.

[0002]

2. Description of the Related Art In recent years, resist materials have become increasingly important in the semiconductor industry and electronic industry. For example, wet etching and dry etching for semiconductor substrates,
Besides being used as a protective film and a sealing material, it is also used as an insulating layer in a multilayer circuit. It is also used in etching resists, solder resists, marking inks, plating resists, cover coat inks, etc. in the production of printed circuit boards. The curing method of the resist material is roughly classified into a thermosetting type and a photocuring type called photoresist. Each of these can be divided into a liquid type and a dry film type. On the other hand, a semiconductor substrate on which a semiconductor element IC is mounted or electric equipment,
Printed wiring boards, which are widely used in electronic devices, have resin laminates with copper foil stretched on the surface, or ceramic materials such as alumina, and conductive layers and insulating layers are alternately provided on the surface. A ceramic substrate is used. As the degree of integration of semiconductor devices increases, higher density packaging and higher density wiring are required.

Therefore, using an organic material as a resist,
A build-up type printed wiring board in which a conductive layer and an insulating layer are alternately and repeatedly stacked as an insulating layer is used, and is described in detail, for example, in "Surface mounting technology", June 1993. For example, SLC (Surfa
What is referred to as “ce Laminar Circuit” is described. This is a build-up type printed wiring board having a structure similar to that of a semiconductor. A general glass epoxy laminate is used as a substrate, and insulating layers of photosensitive epoxy and copper-plated conductor layers are alternately laminated. The conductor layer connection of the laminated part is 125
The photo via hole with a diameter of μm is used. In the example in which the buildup layers are arranged on both sides, SLC layers are laminated twice on both sides of the substrate with a combination of an insulating layer thickness of 40 μm and a conductor thickness of 18 μm. Each of the four signal layers is sandwiched between power supply layers and can control the characteristic impedance to achieve high electrical characteristics. The wiring density is about twice as high as that of a conventional wiring board in which a through hole formed by a mechanical drill is copper-plated for signal connection, due to the minute diameter of the photo via hole. Further, since the conductor layer is thin, the line pitch can be 160 μm at minimum. The high wiring density can reduce the number of wiring layers and the wiring area. Furthermore, since the signal wiring part and the board part are independent, the total thickness can be changed without changing the electrical signal characteristics by changing the thickness of the board part, and the density can be controlled by using a multilayer board. It also has extensibility such that metal can be used. In addition to these features, the high surface wiring density enables high-density semiconductor chips to be bare-chip mounted using flip-chip joints.

The build-up type printed wiring board manufacturing method includes a method using a non-photosensitive insulating material and a method using a photosensitive insulating material. The one using a non-photosensitive insulating material is based on a dry film laminating method. The insulating film coated with the adhesive is adhered together with the copper foil, and the copper foil is etched. Using this as a mask, holes are formed in the lower layer copper foil with an excimer laser. This hole is electrically connected vertically by plating to form a surface pattern. This hole is called a microvia. By repeating this, an arbitrary number of layers can be obtained. This micro via can be dissolved by a chemical depending on the resin such as polyimide. As a build-up printed wiring board made of a photosensitive insulating material, a process of forming a micro via by a photographic method using a photosensitive resin has been developed. In this method, a photosensitive resin is used, holes are formed to connect the upper and lower layers, and conduction is performed by a plating method to form a pattern. In this case, in order to improve the adhesion between the resin layer and the plating layer, the surface of the resin is roughened and a special resin is used. When the insulating resin is applied in a liquid state, the unevenness becomes severe as the number of times of application increases, and the number of layers to be overlaid is limited.
However, it is possible to form a 6 to 8 layer board by forming a pattern on the conductor layer and both sides of the board twice on one side of the board. Also in this case, if the insulating layer is a dry film, the number of layers can be increased.

As described above, although the resist material has many uses, the resist material generally does not have sufficient adhesiveness with other materials on the surface, and is used as a product in a process such as etching or plating. Other materials located on the resist layer during use, such as photomasks, other insulating layers, and conductive layers, may be peeled off. For example, the surface of the conductor is subjected to an oxidation treatment for the purpose of improving the adhesive force between the copper foil and the resin. However, since this film dissolves in acid,
The halo phenomenon occurs due to corrosion from the hole wall by the chemicals used in the subsequent electroless plating process. This is almost unacceptable as the fineness advances. In order to deal with this, a method of reducing the film shape of the oxide film to copper while preserving the film shape, an electroless copper plating method using hypophosphite, tin silane treatment, etc. have been developed. The current situation is that it has not been effective. Therefore, it has been desired to develop a resist material having excellent adhesiveness.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a resist material having excellent adhesiveness, a printed wiring board having excellent adhesiveness using the resist material, and a method for producing the same.

[0007]

Means for Solving the Problems As a result of intensive studies made by the present inventors, fine particles are contained in a resist material and fine particles are removed from the resist layer surface to form fine recesses on the resist layer surface. The present inventors have found that the above-mentioned problems can be solved by the recesses exerting an anchoring effect on other insulating layers and / or conductive layers to be provided next, and have reached the present invention.

That is, the present invention is the following (1) to (10). (1) A resist material containing fine particles. (2) The fine particles are metal, alloy, metal oxide, metal sulfide,
The resist material according to (1) above, which is an inorganic fine particle selected from metal phosphorus compounds, metal halides, glass, and ceramics. (3) The resist material as described in (1) above, wherein the radius of the fine particles is smaller than the thickness of the resist layer. (4) The resist material as described in (1) above, wherein the resist material is a photoresist. (5) The resist material as described in (1) above, wherein the resist material is a non-photosensitive resist.

(6) The photoresist material according to (4) above, wherein the resist material is selected from an epoxy photoresist, a polyimide photoresist, a novolac photoresist and an acrylic photoresist. (7) A resist material containing the fine particles according to (1) above is applied onto a substrate, and fine particles on the surface of the resist layer are chemically and / or physically removed before and / or after curing to form a resist layer surface. A method for producing a printed wiring board, characterized in that a minute concave portion is provided, and a conductive layer and / or another insulating layer is further provided on the surface of the resist layer to repeatedly build up. (8) The method for producing a printed wiring board as described in (7) above, wherein the chemical removal of fine particles is dissolution. (9) The method for producing a printed wiring board as described in (7) above, wherein the physical removal of fine particles is brushing.

(10) A printed wiring board in which a conductive layer and / or another insulating layer is sequentially and repeatedly built up on an insulating layer having minute recesses on the surface formed from the resist material described in (1) above. .

FIG. 1 is a schematic diagram showing a cross section of a layer of a resist material containing fine particles of the present invention, and FIG. 2 shows a state in which fine particles are removed from the surface of the resist layer of FIG. In FIG. 1, a conductive layer 2 such as a copper foil is provided on a substrate 1 such as a glass-impregnated epoxy resin. Further, a resist layer 3 coated with a liquid resist or laminated with a dry resist film is provided. The resist material contains fine particles 4 of metal or glass in advance, and a part thereof protrudes from the surface of the resist layer 3. By chemically treating the surface of the resist layer 3 shown in FIG.
Are chemically dissolved and eluted, and when the fine particles 4 such as glass are removed by physically treating them by, for example, brushing, minute recesses 5 are formed on the surface of the resist layer 3 as shown in FIG. To do. An anchor effect is exerted when these innumerable minute recesses 5 are further provided on another insulating layer and / or conductive layer by coating, chemical vapor deposition, etc., and adhesion with these upper layers is improved. It will be.

In the resist material of the present invention, the type of resist constituting the main component is not limited, and any conventionally known one can be used. Both types of resist, which are applied in a liquid form and solidified and used in a dry film form, are applied. Further, any type of resist such as a non-photosensitive resist, a photosensitive photoresist, an ultraviolet photoresist, an electron beam resist, an X-ray resist and the like can be applied. In the case of photoresist, there are a positive type in which an exposed portion is exposed and a negative type in which an unexposed portion is exposed. Specific examples include epoxy photoresists, polyimide photoresists, novolac photoresists, acrylic photoresists, and the like. As general literature of resist materials, for example, “Recording Materials and Photosensitive Resins” edited by Japan Society for the Promotion of Science (Academic Press, 229-30)
2). The fine particles contained in the resist are not particularly limited as long as they are inorganic and / or organic and can be chemically and / or physically removed from the surface of the resist layer after coating or adhesion of the resist. Examples of the inorganic fine particles include, in addition to metals and alloys, various metal compounds such as metal oxides, metal sulfides, metal halides, sulfuric acid compounds, metal phosphorus compounds, glass, ceramics, carbon fine particles, and the like. . Examples of the organic fine particles include water-soluble polymers and organic solvent-soluble polymers. It is preferable to use a combination in which these fine particles are as different as possible in solubility, hardness, etc. from the resist material as the base material. For example, a combination of fine particles having acid solubility when the resist is alkali-soluble, solubility in water or an organic solvent when the resist is crosslinked and insoluble, and fine particles having a hardness greater than that of the resist are preferable.

There is no limitation on the kind of metal, and Al, Fe,
In, Li, Mn, Mo, Cu, Co, Ni, Zn, S
n, Pb, Ag, Mg, Ba, Si, Ca or the like is used. Also, alloys of these metals, oxides of these metals such as Al ₂ O ₃ , Fe ₂ O ₃ , MnO, ZnO, Na.
₂ O, SiO ₂ , CuO, and other sulfides such as Li ₂ S,
AnS, MoS ₄ , MgS, BaS, PbS, Na ₂ S, etc., halides such as AlCl ₃ , CuCl ₂ , Ag
Cl, ZnCl ₂ , AlBr ₃ , sulfuric acid compounds such as Zn
SO ₄ , Al ₂ (SO ₄ ) ₃ , FeSO ₄ , metal phosphorus compound,
For example _{AlP, InP, Ca 3 P 2} , Ag 3 P, such as SnP, and the like. Further, since the glass fine particles are transparent, they are light-transmissive when the photoresist containing them is cured by light or ultraviolet rays or used as a photomask, and the removal by physical treatment is relatively smooth. It is particularly preferable because it can be performed. There are also no particular restrictions on the ceramic fine particles and the carbon fine particles.

It is preferable that these fine particles have a uniform particle size as much as possible, and the average particle size needs to be small when the resist layer is thin. Its shape is preferably such that the major axis and the minor axis of the particles are substantially equal, and is preferably spherical or elliptic, but not limited to these, and various commercially available fine particles can be used. The thickness of the resist layer is not particularly limited, and a thickness that is practically used is used, but specifically, it is 0.1 to 500 μm, preferably 5 to 30 μm. On the other hand, as for the average particle diameter of the fine particles, the radius may be smaller than the thickness of the resist layer, and a wide range of radius 0.1 μm to 1 mm can be used. These fine particles may be commercially available ones. The method for producing the fine particles is not limited, but a precipitation method, a precipitation method, a liquid phase growth method such as an amalgam method, a thermal decomposition method, a gas phase reaction method, an evaporation-condensation method, or the like, whichever is suitable for each material is selected. You can choose. The method for removing fine particles may be either wet or dry. Among them, examples of the chemical removal method include dissolution removal with water, an organic solvent, or a mixed solvent, and degradative dissolution removal with a chemical such as acid or alkali. Examples of physical removal include brushing, decomposition and evaporation by heat during heat curing of resist, dry etching, and the like. In either case, it is preferable that the resist body is not damaged as much as possible.

By using the resist containing the fine particles of the present invention, a multilayer wiring board can be manufactured by using the build-up method described above. By using the resist of the present invention having excellent adhesiveness as an insulating layer or a part of the insulating layer, the multilayer printed wiring board as a product and as a product is prevented from peeling off the insulating layer and / or the conductive layer, and high precision,
A high-density, high-quality printed wiring board can be manufactured. The substrate to which the build-up method is applied is not limited to the resin-made substrate, and may be the ceramic-made substrate. Examples of the resin substrate include epoxy resin, fluorine resin, and polyimide, and examples of the ceramic substrate include alumina, alumina nitride, and silicon carbide, and those obtained by mixing these with glass powder and firing.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below with reference to examples. Example 1 A copper-clad glass-epoxy resin laminate having a thickness of 400 × 400 mm, a copper foil thickness of 18 μm, and a plate thickness of 1.6 mm was used as a starting substrate. As a resist material, 100 parts of a photosensitive epoxy resin to which 10 parts of substantially spherical uniform glass fine particles having an average particle diameter of 10 μm were added was applied by a curtain coating method to a thickness of 30 to 50 μm and dried. A via hole having a diameter of 125 μm was opened by exposure and development.
After completely curing, the surface was brushed to remove the glass particles on the surface of the resist layer. The surface of the epoxy was etched with permanganic acid, and a 10 μm copper layer was provided on the entire surface by electroless copper plating and electrolytic copper plating. A second wiring layer was provided on this copper plating layer by etching. The above steps were repeated 4 times to obtain a build-up type printed wiring board. Minimum pitch of conductive layer 160μ
m, which was extremely high density. Further, during the manufacturing process and when the product was properly inspected, no peeling phenomenon was observed between the buildup layers.

Example 2 The procedure of Example 1 was repeated, except that an acrylic dry film to which spherical fine particles of copper having an average particle diameter of 5 μm were added in advance was used instead of the liquid resist material. The thickness of this photosensitive dry film was 60 μm. After adhering to the surface of the copper-clad laminate, the surface was treated with sulfuric acid solution to elute the copper spherical fine particles appearing on the surface. As a result, minute recesses were formed on the surface. After coating and drying another liquid photosensitive resist thereon, a via hole having a diameter of 200 μm was opened by exposure and development. Both the dry film and the liquid photoresist were completely cured to improve the adhesion of both layers. After that, the second wiring layer was provided by etching the surface, copper plating, and etching. The above steps were repeated three times on each side of the copper-clad epoxy resin substrate to obtain a multilayer printed wiring board. Due to the anchor effect of the minute recesses on the dry film, the adhesiveness of each layer was high, and no peeling was found during the manufacturing process or during product inspection.

[0018]

As described above, since the resist material of the present invention can form minute recesses on the surface, its anchoring effect improves the adhesiveness to other insulating layers or conductive layers provided thereon. You can

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a layer of a resist material containing fine particles of the present invention,

FIG. 2 shows a state in which fine particles have been removed from the surface of the resist layer of FIG.

[Explanation of symbols]

 1 resin substrate 2 copper foil 3 resist layer 4 fine particles 5 minute recesses

Claims (10)

[Claims] 1. A resist material containing fine particles. 2. The resist material according to claim 1, wherein the fine particles are inorganic fine particles selected from metals, alloys, metal oxides, metal sulfides, metal phosphorus compounds, metal halides, glass and ceramics. 3. The resist material according to claim 1, wherein the radius of the fine particles is smaller than the thickness of the resist layer. 4. The resist material according to claim 1, wherein the resist material is a photoresist. 5. The resist material according to claim 1, wherein the resist material is a non-photosensitive resist. 6. The photoresist material according to claim 4, wherein the resist material is selected from an epoxy photoresist, a polyimide photoresist, a novolac photoresist, and an acrylic photoresist. 7. A resist layer surface comprising applying a resist material containing the fine particles according to claim 1 on a substrate and chemically and / or physically removing the fine particles on the surface of the resist layer before and / or after curing. A method for manufacturing a printed wiring board, characterized in that a minute concave portion is provided on the resist layer, and a conductive layer and / or another insulating layer is further provided on the surface of the resist layer to repeatedly build up. 8. The method for producing a printed wiring board according to claim 7, wherein the chemical removal of the fine particles is dissolution. 9. The method for producing a printed wiring board according to claim 7, wherein the physical removal of the fine particles is brushing. 10. A printed wiring board in which a conductive layer and / or another insulating layer is sequentially and repeatedly built up on an insulating layer formed of the resist material according to claim 1 and having minute recesses on its surface.