JPH04127596A - Manufacture of high frequency wiring board - Google Patents

Abstract

PURPOSE:To enhance a high frequency wiring board in propagation speed of high frequency signal by a method wherein a conductor base film is formed through a vacuum film forming method on a dielectric base film whose surface is treated, the conductor base film is formed into a wiring base pattern, an intermediate dielectric film is formed on a wiring base pattern side, and then the intermediate dielectric film is subjected to a surface treatment. CONSTITUTION:A dielectric base film 12 is formed on a substrate 11. Thereafter, the surface of the dielectric base film 12 is treated to be improved in adhesion to a conductor base film. A film of chrome or titanium excellent in adhesion to the dielectric base film 12 is formed on the dielectric base film 12, and then a conductor base film 13 is deposited thereon. The conductor base film 13 is etched using a resist pattern 14 as a mask. Then, a wiring base pattern 15 is formed. Thereafter, an intermediate dielectric film 16 is formed on all the surface where the wiring base pattern 15 is provided. The intermediate dielectric film 16 is subjected to a surface treatment through the same method with the dielectric base film 12.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method of manufacturing a high frequency wiring board having high density wiring.

<Prior art> The production of high frequency wiring boards is as shown in Figure 2 (i) or i.
v) was carried out by the method shown in the manufacturing process diagram.

As shown in FIG. 2(i), this manufacturing method involves applying a catalyst 32 such as palladium (Pd) on a substrate 31, further forming a resist film 33, and using photolithography and etching techniques as described later. The resist film 33 in the portion where the conductor wiring is to be formed is removed. The application of the catalyst 32 includes:
A vapor deposition method or a wet method is used to the extent that a conductive film is not formed with the catalyst 32.

Next, as shown in FIG. 2(ii), a conductor wiring 34 is formed by depositing electroless copper on the portion from which the resist film 33 has been removed by electroless copper plating.

Subsequently, the resist film 33 is removed, and as shown in FIG.
), the wiring conductor 34 is covered with an intermediate dielectric film 35 made of polyimide resin.

Subsequently, as shown in FIG. 2(iv), the surface of the intermediate dielectric film 35 is mechanically polished until the surface of the wiring conductor 34 is exposed. Then, the first layer wiring is completed.

Further, when performing multilayer wiring, the above steps are repeated using the substrate 31 on which the first layer wiring has been completed.

<Problems to be Solved by the Invention> However, when the intermediate dielectric film is formed of a fluororesin such as polytetrafluoroethylene (PTFE) using the above manufacturing method in order to improve the signal propagation speed, the fluororesin Due to the lack of adhesiveness on the surface, the adhesion of the catalyst becomes extremely poor. For this reason, it is difficult to form conductor wiring on the surface of the fluororesin, making it impossible to use the fluororesin for the intermediate dielectric film. As a result, the intermediate dielectric film cannot be formed of a material having a sufficiently small dielectric constant, and the propagation speed of high-frequency signals cannot be improved.

In addition, mechanical polishing exposes the conductor wiring within the intermediate dielectric film, which complicates the manufacturing process.

The present invention was made to solve the above problems, and
It is an object of the present invention to provide a method for manufacturing a high frequency wiring board that is easy to manufacture and has an excellent propagation speed of high frequency signals.

Means for Solving the Problems> The present invention has been accomplished in order to achieve the above objects.

That is, a dielectric base film is formed on a substrate, the formed dielectric base film is further subjected to surface treatment to improve the adhesion of the conductive base film, and then a conductive base film is formed on the dielectric base film. Next, a wiring base pattern is formed using a conductor base film. Subsequently, an intermediate dielectric film is formed on the entire surface of the wiring underlying pattern, and then surface treatment is performed on the intermediate dielectric film to improve the adhesion of the conductive underlying film. This is a manufacturing method in which the intermediate dielectric film on the wiring base pattern is then removed, and conductive wiring is formed in the portion where the intermediate dielectric film has been removed by electroless plating.

<Function> In the above-described method for manufacturing a high-frequency wiring board, a conductive base film is formed using a vacuum film forming method on a dielectric base film that has been surface-treated, thereby improving the adhesiveness of the surface of the dielectric base film. Therefore, the dielectric base film is formed of a material with a low dielectric constant. In addition, a wiring base pattern is formed using a conductive base film,
After that, by forming an intermediate dielectric film on the wiring base pattern side and then performing surface treatment on the intermediate dielectric film, the adhesion of the surface of the intermediate dielectric film is improved, so the intermediate dielectric film also has a low dielectric constant. formed of material. As a result, the intermediate dielectric film is formed of a material having a low dielectric constant, so that the propagation speed of high frequency signals is increased.

Further, by removing the intermediate dielectric film on the wiring base pattern and then forming the conductor wiring by electroless plating, the surface of the conductor wiring is formed to be flat.

<Example> An example of the present invention will be explained with reference to manufacturing process diagrams shown in FIGS.

As shown in FIG. 1, a dielectric base film 12 is formed on a substrate 11. As shown in FIG. For this dielectric base film 12, a resin having a low dielectric constant, such as fluororesin or polyimide resin, is used. Further, to form the dielectric base film 12, a resin that will become the dielectric base film 12 is applied onto the substrate 11 and cured by heat. Alternatively, a resin film that will become the dielectric base film 12 is attached to the substrate 11.

Thereafter, the dielectric base film 12 is surface-treated to improve the adhesion of the conductive base film, which will be described later. This surface treatment method includes a method of roughening the surface by etching or a method of changing the chemical properties of the surface by plasma treatment.

Then, by using a vacuum film forming method, a metal that becomes a catalyst for electroless copper plating is applied onto the dielectric base film 12, for example! A conductive base film 13 of M (Cu) is formed. For the vacuum film forming method, a vacuum evaporation method, a sputtering method, or the like is used. In addition, dielectric base film 1
2 and the conductive base film 13 (if not, a metal film with excellent adhesion to the dielectric base film 12, such as a chromium (Cr) film or a titanium (
After forming the Ti film, a conductive base film 13 is formed.

Next, a resist film is formed on the conductor base film 13. Thereafter, as shown in FIG. 1 (2), a resist pattern 14 is formed using a resist film by photolithography, and the conductive base film (13) is etched using this resist pattern 14 as an etching mask. Then, a wiring base pattern 15 is formed.

Thereafter, as shown in FIG. 1 (2), an intermediate dielectric film 16 is formed on the entire surface of the 15 wiring base patterns. This intermediate dielectric film 16 is formed by the same method as the base dielectric film 12. Then, the surface treatment of this intermediate dielectric film 16 is performed in the same manner as the surface treatment of the dielectric base film 12.

Next, a resist film is formed on the surface of the intermediate dielectric film 16,
As shown in FIG. 1, the resist film on the wiring underlying pattern 15 is removed by photolithography to form a resist pattern 17. Thereafter, using the resist pattern 17 as an etching mask, the intermediate dielectric film 16 (double-dashed line) on the wiring base pattern 15 is removed using an anisotropic etching technique to prevent undercutting.

Then, as shown in FIG. 1, copper is deposited on the wiring base pattern 15 by electroless copper plating in the area where the intermediate dielectric film 16 has been removed, thereby forming the conductor wiring 1-8.

This deposition surface becomes a flat surface, and the copper is deposited on the intermediate dielectric film 1.
This is done to a height that forms the same plane as the surface of 6.

As described above, since the surface of the conductor wiring 18 is formed flat by the electroless plating method, the step of exposing the upper surface of the conductor wiring 18 from the intermediate dielectric film 16 by mechanical polishing as in the conventional manufacturing method is not necessary. There's no need to do it.

In the manner described above, the first layer of wiring is formed on the substrate 11.

Furthermore, when performing multilayer wiring, after the process described in FIG.
A conductive base film similar to that described above is formed on the upper surface of 8.

Then, from the process explained in FIG. 1■, the process shown in FIG.
By sequentially performing the steps up to the steps described above, the 2N-th wiring is formed.

To form the 3Nth and subsequent wirings, the 2nd J! The process of forming the eye wiring may be repeated.

<Effects of the Invention> As described above, according to the manufacturing method of the present invention, a conductive base film is formed on the surface-treated dielectric base layer by a vacuum film forming method, and the conductor base film is further used to form a wiring base film. The pattern was formed, and then the intermediate dielectric film was formed on the wiring base pattern side, and the surface of the intermediate dielectric film was then treated.
The adhesion between the conductor base film or intermediate dielectric film and the conductor wiring is improved. As a result, the conductive base film and the intermediate dielectric film can be formed of a low dielectric constant material, so that the propagation speed of high frequency signals can be improved.

In addition, since the conductor wiring was formed by electroless plating,
Since the upper surface of the conductor wiring is formed flat, a mechanical polishing step can be omitted. As a result, manufacturing of the wiring board becomes easier.

[Brief explanation of the drawing]

FIG. 1 is a manufacturing process diagram of an embodiment, and FIG. 2 is a manufacturing process diagram of a conventional example. 11... Wiring board, 12... Dielectric base film. 13... Conductor base film, 15... Conductor base pattern. 16... Intermediate dielectric film, 18... Conductor wiring.

Claims (1)

[Claims] A step of forming a dielectric base film on a substrate, then performing surface treatment on the dielectric base film, and then forming a conductive base film on the dielectric base film by a vacuum film forming method. forming a wiring base pattern using the conductive base film; forming an intermediate dielectric film on the entire surface of the wiring base pattern, and then subjecting the intermediate dielectric film to surface treatment; and forming the wiring base pattern. Manufacturing a high-frequency wiring board characterized by comprising: a step of removing the intermediate dielectric film above; and a step of forming conductor wiring by electroless plating on the portion from which the intermediate dielectric film has been removed. Method.