JPS5861648A - Composite insulating film and etching method therefor - Google Patents

Abstract

PURPOSE:To avoid disconnection, by superposing an inorganic insulating film having a window wherein the aperture is included inside on a high polymer resin film with the aperture on a substrate. CONSTITUTION:On the inorganic insulating film 13 of the high polymer resin film 12 on the substrate, a resist mask 14 with the aperture slightly larger than the fixed dimension is applied and etched resulting in window opening 15'. Next, the resist mask 14' having a window with the fixed dimension inside the window 15' is provided, and the high polymer resin film 12 is etched resulting in the aperture 15''. The mask 14' is removed, and a metallic electrode 16 is evaporated. In this constitution, overhang does not generate, and accordingly a wiring structural body without disconnections can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a composite insulation film, and particularly to a composite insulation film provided on a wiring board or a semiconductor substrate.

This is extremely effective when forming through holes in the membrane.

In recent years, polymer resin films, particularly polymer resin films mainly made of polyimide resins, have been widely used as multilayer wiring insulating films for wiring boards and LSIs. If an attempt was made to use only a polymer resin film as an interlayer insulating film for the above-mentioned wiring, the film would have to be thick due to reliability of dielectric strength, and microfabriability would be sacrificed. Furthermore, since the inorganic insulating film alone has poor coverage of the underlying step, a thick film is ultimately required to obtain the necessary withstand voltage. Therefore, as a conventional method to eliminate both of the above-mentioned drawbacks, attempts have been made to first use a polymer resin film to reduce the level difference in the base layer, and then form a double composite insulating film by forming an inorganic insulating film. It was getting worse. However, although the schematic configuration of this structure is shown in FIG. 1, when forming through holes in this structure, the following disadvantages occur.

That is, as shown in FIG. 1a, a polymer resin film 2 is formed on a substrate 1.
After forming an inorganic insulating film 3, a photoresist film 4 is formed and an open pattern 5 is provided at a predetermined position. Note that the substrate here may include a metal conductive layer, a protective film, and the like. The same applies below. Next, as shown in the same figure, the inorganic insulating film 3 exposed in the opening 5 is etched to form an opening 5' in the inorganic insulating film 3, and subsequently, the polymer resin film 2 is etched as shown in FIG. An opening 51 is provided. Finally, as shown in Figure d, the photoresist is removed to complete the through-hole formation, but when it is formed in this way, the inorganic film protrudes onto the shoulder of the through-hole, resulting in an overhang, as can be seen from the shape in Figure d. When the wiring conductor layer is subsequently deposited, the conductor layer will be disconnected at this portion.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a through-hole shape and a method for forming the same, which eliminates the above-mentioned drawbacks.

The structure of the present invention for achieving the above object is to provide an inorganic insulating film having an opening window containing the opening part inside on a polymer resin film having an opening part formed on a substrate. be.

The above resin film thickness is 0.5 to 2 μm1 Insulation film thickness is 0.5 to 2 μm
μm, and it is important that the opening window of the insulating film is 0.1 to 5 μmφ wider than the diameter of the opening of the resin film.

Outside the above range, it will not be possible to provide a lead line or the like that is better than the opening window. The resin film may be made of any material as long as it has good adhesion to the substrate and is insulating, but polyimide resin is preferred from the viewpoint of processability. Furthermore, as the inorganic insulating film formed on the resin film, an oxide film, a nitride film, and a metallic insulating film can be used without any difference, and the same effect can be obtained. A specific manufacturing method for configuring the above invention will be explained using the drawings.

As shown in FIG. 2A, an opening 15' is formed in the inorganic film 13 by forming an opening slightly larger than a predetermined size with a photoresist [14GC], and etching the opening 15'.

After this, before etching the polymer resin film, a second photoresist film 14' is formed, and a photoresist opening pattern of a predetermined size is formed inside the opening 15'.
(b), the polymer resin film 12 is etched to form a predetermined opening 15'' (FIG. 2C). After that, the photoresist is removed (FIG. 2d). Next, a known metal vapor deposition technique and its processing are used. A metal electrode film 16 is provided in the opening portion 15'' using a technique. In this way, an opening with a predetermined size is formed in the polymer resin film, and an opening with a larger size than the predetermined size is formed in the inorganic film thereon.

Example 1 An example will be described using FIG. 2. Using Si as the substrate 11, the surface was thermally oxidized to form a SiO2 film (not shown), and then a first wiring trench layer was formed (not shown). The ↓th layer wiring trench layer was made of At with a thickness of 1 μm.

Next, as a polymer resin film 12, a prepolymer solution of polyimide-in-indolo-yanarizolinedione (hereinafter abbreviated as PIK) was spin-coated and cured by heating to form two PIK films on top of one PIK film. PIK prepolymer liquid has a viscosity of 0.6
PIK film 1 with a thickness of 0.8 μm after being heated and cured by spin coating at 4000 rpm using Pa-8 and concentration izowtst.
2 on the membrane. Thereafter, a silicon nitride film was formed as an inorganic film 3 to a thickness of 0.5 μm by plasma CVD. After that, 0MR83 was used as the photoresist 14, and the diameter was 10 μm.
After exposing and exposing a mask pattern having openings, the silicon nitride film 13 was etched. In this example, etching was performed by dry etching using CF.

Of course, wet etching is also possible. Next, the photoresist film 14' was exposed and developed again using 0MR83 to form a mask pattern of a predetermined size having an opening hole of 8 μmφ.
The PIK film 2 was etched with a mixed etchant of hydrazine hydrogen chloride and ethylenediamine to form an opening 151. Thereafter, the photoresist film was removed using Photoresist Peeling 8502 (trade name, manufactured by Tokyo Ohka Co., Ltd.). In this way, a through pole having the cross-sectional structure shown in FIG. 2d was formed. Next, using a known conductive wiring formation technique, a second
As shown in Figure e, an At wiring 16 with a thickness of 1 μm was formed. No breakage occurred at the shoulder or step portion of the opening, and a good conductive pattern could be formed.

As detailed above, the present invention provides an inorganic insulating film having an opening larger than the opening on a polymer resin film having an opening, thereby providing a through hole without disconnection. It's a huge profit.

The present invention is not limited to the above-described embodiments, and it is clear that those skilled in the art can easily apply other materials such as film materials or photoresist materials; It is clear that the invention does not fall outside the scope of the right of the invention.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a process for explaining a conventional technique, and FIG. 2 is a cross-sectional view of a manufacturing process of a composite insulating film as an embodiment of the present invention. 11... Substrate, 12... Polymer resin film, 13...
Inorganic film, 14.14'... Photoresist, 15.15
'.゛2, Ni L vi1 fig. 2 fig.

Claims (1)

[Claims] 1. A composite insulating film comprising a substrate, a polymer resin film formed on the substrate and having at least an opening, and an inorganic insulating film formed on the resin film. . A composite insulating film, wherein the inorganic insulating film has an opening window that includes the opening inside. 2. Forming a polymer resin film on the substrate, then forming an inorganic insulating film on the film, then forming a predetermined opening in the insulating film using a first photoresist film, and then Immediately a step of forming a second photoresist film on the photoresist film and the opening portion, and then a step of forming a predetermined opening window in the polymer resin film of the opening portion using the second photoresist film. Then, the first
and a step of removing the second photoresist film.