JPS61271897A - Multilayer wiring circuit board and manufacture thereof - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to an organic polymer insulating film used for multilayer wiring circuit boards, particularly thermal printer heads, optical printer heads, circuit boards for mounting highly integrated high-frequency ICs, etc. The present invention relates to a multilayer wiring circuit board having a multilayer wiring circuit board.

(Prior art) With the remarkable development of electronic technology in recent years, electronic devices have become smaller and l! Demand for quantification and higher performance is increasing, and as a result, efforts are being made to increase the degree of integration of device components.

As a method for achieving high integration, a method of integrating film circuit components such as thermal printer heads, digital printer heads, and circuit boards for mounting highly integrated high-frequency ICs using multilayer wiring boards has been used.

Currently, there is a strong demand for miniaturization, high density, and high-speed signal transmission for such multilayer wiring board components. Various methods and materials have been adopted to meet these requirements, such as using insulating materials with low dielectric constants.

(Problems to be Solved by the Invention) However, in miniaturized and high-density membrane circuit components, they generally have a multilayer wiring structure in which two or more wiring conductors are stacked with an insulating layer interposed between them. The adhesion strength between each layer must be sufficiently stronger than that of a single-layer product, otherwise peeling from the interface often occurs during wiring processing and heat treatment.

In addition, if the adhesive strength is not sufficient, in the step of applying 7 Otrenost on the formed wiring conductor and processing the film,
The photoresist may float or peel off from the wiring conductor, resulting in a problem that when etching the wiring conductor, even the portion that should be left as the final wiring corrodes.

Both of these occur because the chemical bond at the interface is weak and because the underlying surface is sufficiently flattened and the effective area of the adhesive interface is insufficient.

In addition, if the surface of the insulating layer is sufficiently flat, the internal stress between the edge layer and the wiring conductor will hardly be absorbed and relaxed by the insulating layer during wiring processing, heat treatment, etc. There is a problem that peeling and cracking occur.

(Means for Solving the Problems) The inventor of the present invention has discovered that 2n, I! As a result of repeated research to solve the problem, the present invention has been completed.(1) A wiring conductor and an organic polymer insulating film are formed in a multilayer structure on an electrically insulating substrate. In the multilayer wiring circuit board, the grown polymer insulating film is filled with solid particles, and the surface roughness of the insulating material film has a center line average roughness Ra of 1.5 to 0.5μ. A multilayer wiring circuit board characterized by This is a method for manufacturing a multilayer wiring circuit board, characterized in that the adhesion between the substrate and the polymeric insulating material film is strengthened.

Next, in a combination in which an electrical wiring conductor and an organic or organic polymer insulating film layer are formed on an electrically insulating substrate such as ceramic or glass, the polymer insulating material is filled with solid particles that have a strong affinity with it. , obtained by mixing ζ)
The multilayer wiring circuit board of the present invention having an insulating film with a roughened surface will be described.

6i) As the wiring conductor, aluminum (Δ1), copper (Cu), gold (Au), silver-Pafnoum (Ag-Pd)
) is used, and a film is formed by conventionally well-known RI, film techniques, vapor deposition, sputtering, CVD, and other thin film techniques, and a wiring pattern is processed by printing technology or 7-orthogonography technology. Here, as the organic polymer insulating material, an electrically insulating material with excellent heat resistance and chemical resistance, such as 7 er/-, butadiene, polyimide, etc., is used, and solid fine particles filled in the electrically insulating material are used. Therefore, it is preferable to use a powdery hardened solid material that is similar to the polymer insulating material and has a strong affinity with the polymer insulating material. It is also preferable to use electrically insulating Kuroiso materials such as glass and ceramics as long as they have a strong affinity. Among other things, filling and mixing polyimide resin as an organic polymer insulating material with heat-cured polyimide resin powder of the same type as a filler is a particularly recommended combination example. It is also good to use it as a filler.

Regarding the size of the solid particles filled in the polymeric insulating material, when an electrical wiring conductor is formed on an insulating film formed of the polymeric insulating material, the diameter is 1 to 15 μm.
It is preferable that the volume average diameter is about 7μ(1) or less, and by doing so, the step coverage of the electrical wiring conductor with respect to the insulating film and the 7 othrenost film used when patterning the electrical wiring conductor are improved. It is possible to suppress step coverage and variations in the thickness of the insulating film. In addition, the amount of solid particles is 10 to 35% by weight, and the shape thereof may be spherical or irregular.

Then, the polymeric insulating material filled with the solid particles is formed into a film on the electrical wiring conductor formed on the electrically insulating substrate by a method such as a spinner, a roll coater, or printing.
Further, through-holes for connecting upper and lower electrical wiring conductors or patterns for protecting lower-layer electrical wiring conductors are formed by employing conventionally well-known 7↑trilithography technology and printing technology.

Here, a method for forming an insulating layer will be described in which film formation using the printing technique of the polymer insulating material containing solid particles and through-hole processing for connecting upper and lower electrical wiring conductors are simultaneously performed. That is, after forming an electrical wiring conductor on an electrically insulating substrate, the formation method is carried out by screen printing using a melt-resistant M stainless steel screen plate such as a metal mask or a PVA (polyvinyl alcohol) mask. In this case, the surface roughness of the insulating film subjected to dry heat treatment is the center line average roughness J
IS-B12O3-1976) It is important to perform printing so that Ra is about 1.5 μm0 or less. The reason for this is to suppress variations in the step coverage of the respective films and the insulating layer 11J7 when forming the electrically arranged IA conductor on the insulating film and when processing the 7t) Renost film on the wiring conductor. Surface roughness Ra is 1.5μ
As shown in FIG. 2, after passing the spear, a portion of the solid particles 2 forms a grown polymer insulating film (for example, polyimide resin) 1.
There is also a problem in that the wires protrude and are exposed from the surface of the electrical wiring conductor layer 3, resulting in disconnection in the electrical wiring conductor layer 3.

When the surface roughness is lower than 0.5 μm, the adhesive strength between the film layers becomes low, and it is impossible to obtain a multilayer wiring circuit board having a film with strong adhesive strength, which is the objective D of the present invention.

Therefore, the surface roughness is preferably in the range of Ra 0.5 to 1.5 .mu.-, and in this case the cross-sectional state as shown in FIG. 1 is obtained.

Absolute #a III according to the present invention! In order to confirm the adhesive strength of the pad, a conductive material of aluminum (Δl) was formed by a vacuum & deposition method on a polyimide resin insulating crotch with a center line average roughness RIL of 0.2 μm or less, and a pad was formed by photolithography. When the pads were formed and subjected to a tensile test using adhesive tape, 20% of the pads showed delamination. In contrast, aluminum film formed on a polyimide resin insulating crotch with a centerline average 11. (200°C x 30 minutes).

However, according to the method of implementing the present invention, there is an advantage that film formation and pattern processing for connecting upper and lower wiring conductors can be simultaneously formed in -times of printing.

A comparison between the example process of the present invention and the conventional process is shown below.

m4” [0yu K-mei” L0-work book 1” ■L1
, Polyimide 1. Polyimide 1. poly i mi
Coating Coating Printing 2, drying, heat treatment 2. Pre-bake 2. Heat treatment 3
．． 7 Otorenos) 3. Exposure coating 4, Brebake 4. Development 5, exposure 5. Heat treatment 6, Development, Bost bake 8, Polyimide etching 9.7 Otoresist peeling (effects of the invention) Since the present invention is constructed as described above, it exhibits the following effects.

(a) When an organic polymer insulating material is filled with solid particles and the surface of the insulating film is roughened, the effective surface area of the adhesive interface increases, so that the adhesion at the interface between the insulating film and the upper wiring conductor is improved. (b) Furthermore, the adhesion of photorenost used for processing the wiring conductor on the surface-roughened insulating film is also improved. (C) Due to the surface roughening of the insulating film, even if wiring conductor processing, heat treatment, etc. are performed, the insulating film absorbs and relieves the internal stress between the insulating film and the wiring conductor above it, resulting in peeling and cracking of each film. The occurrence of is suppressed. (d) Even with adhesive growth polymer materials such as polyimide face,
Filling with solid particles gives chicken tropism, which makes it easy to transfer to a printing material through a screen mesh, making screen printing possible. (
C) And, since film formation and pattern processing for connecting upper and lower wiring conductors are simultaneously formed in - times of printing, compared to pattern processing using the conventional well-known 7 otolithography technology,
It decreases to 172 to 1/4. (r) Furthermore, since the processing itself is simplified, reliability is also greatly improved.

(g) By layering a solid substance with a sufficiently small coefficient of thermal expansion on the organic polymer insulating material, the coefficient of thermal expansion can be made close to that of the wiring conductor, so even if the wiring is laminated, there will be no difference in the coefficient of thermal expansion. This problem can be solved, and peeling of each film can therefore be prevented. (h) When an organic polymer insulating material is filled with solid fine particles (such as ceramic powder with good thermal conductivity) that have a sufficiently high thermal conductivity, generation occurs from elements inserted or mounted on a multilayer wiring circuit board. This allows the amount of heat to be radiated to the outside of the board, thereby preventing deterioration of the characteristics of the circuit board due to temperature rise.

[Brief explanation of drawings]

FIG. 1 is a partially enlarged sectional view of an embodiment of the present invention, and FIG. 2 is a partially enlarged sectional view of the embodiment. 1: Organic polymer insulating film 2: Solid fine particles 3: Electric wiring conductor layer

Claims (6)

[Claims] (1) In a multilayer wiring circuit board in which a wiring conductor and an organic polymer insulating film are formed in multiple layers on an electrically insulating substrate, the organic polymer insulating film is filled with solid particles, and the insulating material The surface roughness of the film has a center line average roughness Ra of 1.5.
A multilayer wiring circuit board characterized in that the thickness is 0.5 μm. (2) The multilayer wiring circuit board according to claim 1, wherein the solid particles are a thermosetting material similar to the organic polymer insulating film. (3) The multilayer wiring circuit board according to claim 1 or 2, wherein the solid particles and the organic polymer insulating film are polyimide resin. (4) By forming a multilayer organic polymer insulating film filled with solid particles and a wiring conductor on an electrically insulating substrate, the adhesion between the wiring conductor and the polymer insulating material film is strengthened. A method for manufacturing a multilayer wiring circuit board, characterized by: (5) The method for manufacturing a multilayer wiring circuit board according to claim 4, wherein the solid fine particles are a thermosetting material similar to the organic polymer insulating film. (6) The method for manufacturing a multilayer wiring circuit board according to claim 4 or 5, wherein the solid particles and the organic polymer insulating film are polyimide resins.