JPS59100537A - Formation of electrode wiring - Google Patents

Abstract

PURPOSE:To perform an etching that influences by aluminum oxidized layers on the surface of an Al film have been removed by a method wherein an ion implantation treatment is performed on metal films including aluminum, and, after that, a dry etching is performed. CONSTITUTION:An SiO2 film 2 is formed on a semiconductor substrate 1. An Al film 3 is coated on the SiO2 film 2. Photoresist films 4 are provided on the Al film 3 for forming the prescribed pattern. An ion current is exposed to the photoresist films 4 and the Al film 3 exposed at the pattern apertures thereof and an ion implantation is performed. Then, a reactive ion etching is performed using carbon tetrachloride as the etching gas.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to a method for forming electrode wiring by etching a metal film into a fine electrode wiring pattern.

Conventional Structures and Problems Therefor, for example, the electrode wiring of a semiconductor device is formed by forming an aluminum (Al) film or an aluminum alloy film (hereinafter simply referred to as M film) on the surface of a predetermined semiconductor substrate. A desired shape is formed by etching the photoresist film mask faithfully. Recently, an ion etching method called a dry etching method has been used for this etching process, in which chemically inactive ions or chemically active ions are injected in a direction perpendicular to the surface of the object to be etched. It's starting to look like this. In particular, the so-called reactive ion etching method, which uses chemically active ions, is suitable for microfabrication of Al films, and is often used as a method for forming electrode wiring in semiconductor devices. However, it is well known that Al films tend to form a thin aluminum oxide layer (A1203) on the surface. For example, it is well known that when an A7 film is exposed to air even at room temperature, the surface converts into an oxide layer. The oxide layer differs from the A7 film in that it is resistant to ion etching. In addition, the thickness of the aluminum oxide layer on the Aβ film varies by several tens of angstroms;
Wobble also causes variations in the etching rate in ion etching, and in the past, this has caused non-uniformity in etching rate between wafers, for example, when ion etching is performed using the Sochi process.

Furthermore, the etching rate ratio between the Al film and the ordinary photoresist film is small, and there are many difficulties in processing fine patterns with high precision.

OBJECTS OF THE INVENTION The present invention provides a method for forming electrical wiring, which not only enables uniform etching of an Al film, but also greatly improves the etching rate ratio between the Al film and the photoresist film. It is something.

Components of the Invention In summary, the invention includes a step of performing ion etching after ion implantation into a metal film containing aluminum. According to this, the surface of the Al film is exposed to ion bombardment. As a result, the etching speed increases and etching becomes easier.

DESCRIPTION OF EMBODIMENTS FIGS. 1 to 4 show embodiments of the present invention, and are sectional views showing the steps of manufacturing a semiconductor device. In FIG. 1, a silicon dioxide (Si02) film 2 is formed on a semiconductor substrate 1 by a thermal oxidation method or a chemical vapor deposition method (hereinafter referred to as CVD method). Next, as shown in FIG. 2, an Al film 3 is deposited on the 5102 film 2. In addition to aluminum for electrodes, the human membrane 3 is made of A,
Commonly used aluminum alloy films such as l-3i, ) and l-3i-Cu can be used. Next, as shown in FIG. 3, a photoresist film 4 is provided on the KLL film, and is formed into a desired pattern by a well-known photolithography technique. In FIG. 4, the photoresist film 4 and its pattern openings are exposed.
r) Ion flow 5 is applied to the lt film 3 to perform ion implantation. The conditions for ion implantation are, for example, boron ions, acceleration voltage 5oKeV, dose amount 5x1o'', tz%4
It was executed with In addition, the conditions for ion implantation (implantation) (bow 1
, the ions were selected from voronophrine, alkone, and silicon, and the implantation amount was 3×1015 to 3×10.
It was possible to optimally set the acceleration voltage to 15 ions/Ca + sc) KeV or less.

+) After performing the ion implantation process described in ij, using an ion etching device with a normal parallel plate electrode structure,
Reactive ion etching is performed using carbon tetrachloride as an etching gas. According to this ion etching, the surface portion of the J film exposed in the pattern opening in the previous ion implantation process was subjected to ion bombardment and transformed into a damaged layer with a high etching rate. The first resist film 4 is modified into a layer with a low etching rate by ion bombardment, and as a result, the etching rate ratio between the Al film 3 to be etched and the photoresist film 4 serving as its resistance mask, that is, the selectivity is improved by 2 to 3 times compared to the conventional method.

On the surface of the ion-implanted A/film, the etching rate in ion etching is increased to form a deep damage layer that exceeds the variations in the aluminum oxide layer.
Uniform etching begins across the entire surface, improving the uniformity of the etching rate over the entire surface. Therefore, it has become possible to process even fine-sized patterns with high precision and uniformity. Also, when batch processing was performed, the variation between treatments was significantly reduced and the uniformity was significantly improved. - To give an example, using an ordinary Al film and a photoresist film, boron is
When ion implantation was performed at a dose of 5 x 10" ions/c4 and ion etching was performed in a batch process on a pattern with a size of 2 μm, the uniformity among wafers was 95 coefficients or higher, and it was practically Differences between batches were eliminated.

Effects of the Invention According to the present invention, it is possible to perform ion etching that removes the influence of the aluminum oxide layer on the surface of the A7 film, and as a result, electrode processing using the human film as an electrode wiring layer can be realized with uniformity and high precision. For example, the present invention has great benefits, such as making it easier to form electrode wiring for ultra-high-integration semiconductor devices and high-frequency semiconductor devices that require fine patterns.

4%+7-11111vノ1nl=1"'Yoti7L'
15 FIGS. 1 to 4 are process-sequential sectional views showing an embodiment of the present invention.

1...Semiconductor substrate, 2...Silicon dioxide, 3-...Al film, 4...Photoresist film, 5...Ion flow.

Claims (1)

[Scope of Claims] (1) A method for forming electrode wiring, characterized in that a metal film containing aluminum is subjected to ion implantation treatment, and then dry etching is performed. ? 2. The electrode wiring forming method according to claim 1, wherein a metal film containing aluminum is covered with a photoresist pattern, and ion implantation treatment is performed in conjunction with the photoresist surface. (3) In the ion implantation process, the implanted ions are boron and phosphorus. Either argon or argon, and the injection amount is 3
×10~3×1015 ions/Ca with acceleration voltage of 60
The electrode wiring forming method according to claim 1 or 2, which is carried out under conditions of KeV or lower.