JPH0216568A - Production of semiconductor - Google Patents

Abstract

PURPOSE:To simplify stages and to allow fine processing so that film thicknesses are reduced and fine conductive layers can be formed by bringing a silicon compd. into vapor phase reaction with the radicals generated in exposed parts by selective exposing of a photosensitive org. resin, then by treating the compd. by oxygen plasma. CONSTITUTION:An interlayer insulating film 4 is formed by coating the photosensitive polyimide resin and is selectively exposed by using UV rays 5 except the regions to be apertured. The radicals 6 are generated in the exposed parts. The silicon compd. 7 is brought into vapor phase reaction with the radicals 6 to incorporate the silicon therein. Etching by the oxygen plasma is thereafter executed. The radical parts subjected to the vapor phase reaction with the silicon compd. are changed to a silicon oxide film 8 by the oxygen plasma and this film serves as an etching mask to the oxygen plasma. Only the unexposed parts are thus etched away. The stages are simplified in this way and since the interlayer insulating film is directly etched, the fine processing is possible. The formation of the thin films is possible in case of using said film as the etching mask for the conductive layers. The fine conductive layers are thus formed.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for manufacturing a semiconductor device, and more particularly to a method for etching a photosensitive organic resin film into a predetermined pattern.

<Prior Art> Conventionally, when forming a through hole using an organic resin as an interlayer insulating film, a method has been used in which the organic resin film is etched using a photoresist as a mask. However, when a photoresist is used as a mask, the etching rate of the 7-photoresist is about 1.5 times the etching rate of an organic resin film in dry etching using a gas mainly composed of oxygen. microfabrication is difficult. Therefore, in order to increase the selectivity to the organic resin film, a metal layer is provided as an intermediate layer between the photoresist and the organic resin film, the metal layer is etched using the photoresist as a mask, and then the organic resin is etched. The openings were formed by a two-step etching method in which the membrane was etched.

Furthermore, in the formation of the metal layer or the conductive layer that electrically connects between elements and wiring, etc., a conventional photoresist is used as an etching mask. The pattern was formed by coating the film to a thickness of 100 mL and then performing processes such as exposure and development.

<Problems to be Solved by the Invention> When a metal layer is used as a mask for etching an organic resin film, the selectivity to the organic resin film can be made larger than when a photoresist is used. The layer formation, removal, and etching steps are increased and complicated. Further, as the size becomes even finer than the current level, it is necessary to make the metal layer thinner in order to etch the metal layer as a mask using a photoresist as a mask, making it difficult to etch a thick organic resin film.

Furthermore, when etching the conductive layer including the metal layer, the photoresist that serves as a mask is also etched, making it impossible to reduce the thickness of the photoresist coating, which hinders miniaturization. Means for Solving the Problem> In a method of forming a photosensitive organic resin film on a semiconductor substrate on which a conductive layer is formed and selectively etching the photosensitive organic resin film, the photosensitive organic resin is By performing selective exposure, the radicals generated in the exposed area are converted to silicon, and the metal material is caused to undergo a vapor phase reaction to contain silicon.Then, the exposed area is changed to a silicon oxide film by oxygen plasma, and the unexposed area is converted to silicon. Remove by etching.

Function: It becomes possible to etch organic resin films without using photoresist or other etching mask materials, and silicon oxide films formed by oxygen plasma are almost completely etched by oxygen plasma. Instead, only the organic resin film can be effectively removed.

When etching a conductive layer, if the present invention is applied to form an etching mask instead of using the current 7 photoresist development method, the etching mask surface is changed to a silicon oxide film, which improves the selectivity with respect to the conductive layer. becomes larger, and the organic resin used as the etching mask can be made thinner.

<Embodiment> FIGS. 1(a) to 1(e) are cross-sectional views showing an embodiment of the through-hole forming method according to the present invention.

In FIG. 1(a), a silicon oxide film 2 is formed on a silicon single crystal substrate l, an A1-Si film is formed thereon by sputtering, etc., and wiring 3 is formed in a predetermined pattern.
form. Next, as shown in FIG. 1(b), a photosensitive polyimide resin is applied to form an insulating film 4 between the eyebrows with a thickness of 1 μm to 2 μm.
form. Next, areas other than those to be formed as through holes are selectively exposed using ultraviolet rays 5 as shown in FIG. 1(c).

Radicals 6 are generated in the exposed area as shown in FIG. 1(d), and a silicon compound 7 is added to the radicals 6 at
Silicon is incorporated by performing a gas phase reaction while heating to ℃. Currently, HMDS is the silicon-based compound.
(hexamethylene disilazane) is known.

After that, as shown in FIG. 1(e), etching is performed using an oxygen plasma, but the radicals that have reacted with the silicon-based compound in the gas phase are removed from the surface by the oxygen plasma.
The silicon oxide film 8 is changed to a thickness of ~20 OA, and serves as an etching mask for oxygen plasma, and only the unexposed areas are etched away to form openings.

<Effects of the Invention> In the method of forming through-holes in interlayer insulating films using organic resin, the present invention does not require the use of conventional etching masks such as photoresists or metal layers as intermediate layers, so the process is simplified. Not only is the process simplified, but since the glabellar insulating film is directly etched, fine processing is possible without being limited by the thickness of the etching mask. When using a photosensitive organic resin film as an etching mask for a conductive layer, by developing it according to the present invention, it is possible to form a thin organic resin film and form a fine conductive layer. becomes.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1(a) to 1(e) are cross-sectional views showing the manufacturing process of an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1...Silicon single crystal substrate, 2...Silicon oxide film, 3...Al-8i wiring, 4...Photosensitive organic resin film, 5...Ultraviolet light, 6...Radicanope 7. ...Silicon-based compound, 8...Silicon oxide film changed by oxygen plasma.

Claims (1)

[Claims] 1. A method of forming a photosensitive organic resin film on a semiconductor substrate on which a conductive layer is formed, and selectively etching the photosensitive organic resin film, comprising: It is characterized by the following steps: a step of selectively exposing the exposed area, a step of reacting a silicon-based compound with the radicals generated in the exposed area in a gas phase, and a process of converting the exposed area into a silicon oxide film using oxygen plasma and etching away the unexposed area. A method for manufacturing a semiconductor device.