JPS5980929A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To form the surface to a curved surface shape, and to prevent the generation of a defect such as a crack in the end section of the wiring of a passivation film by etching an aluminum film formed on a substrate to a predetermined electrode shape and thermally treating the whole under vacuum or in an inert gas through a high-speed heating method. CONSTITUTION:A silicon dioxide film 2 is formed to the surface of the silicon substrate 1 through a thermal oxidation method. A predetermined opening section is formed, and an impurity forming a P-N junction to the silicon substrate 1 is diffused and introduced through the opening section to form a diffusion region 3. An electrode wiring layer 4 consisting of the aluminum film is formed on the diffusion region 3, and the aluminum-film electrode wiring layer 4 is changed into a gentle curved-surface shape by melting through heat treatment by quick heating in a short time under vacuum or in the inert gas. The layer 4 is coated with a silicon dioxide film 6 consisting of the passivation film.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF THE INVENTION The present invention relates to a method of manufacturing a semiconductor device, and particularly to a method of manufacturing a semiconductor device including a step of treating an aluminum film electrode wiring layer provided on a semiconductor substrate.

Conventional Structures and Their Problems Semiconductor devices in which desired functional elements are provided in a semiconductor substrate often have a structure in which wiring electrodes are provided and then a passivation film is provided to cover these electrodes. This passivation film is usually formed using a silicon oxide film or a silicon nitride film using a vapor phase deposition method (hereinafter abbreviated as CvD), but since it is provided at the final stage of the manufacturing process, cracks etc. may occur in this film. If a defect exists, it is almost impossible to repair it in subsequent steps, which causes defects over time.

Looking at the conventional semiconductor device shown in FIG. 1 in detail, a silicon oxide film 2 is provided on the surface of a semiconductor substrate 1 as an insulating film for selective diffusion, a predetermined opening is formed in this, and then the opening is A diffusion region 3 of a conductivity type opposite to that of the substrate 1 is formed through the substrate 1, and an aluminum metal wiring layer 4 forming an ohmic contact is provided thereon, and then a passivation film 5 made of a silicon oxide film is formed over the entire surface. In this case, the end portion of the aluminum metal wiring layer 4, that is, the intersection tip 6 of the etched surface of the pattern and the flat surface is sharp, and cracks 7 are likely to occur in the portion covering this. Furthermore, even in the case where the rack does not fit into the neck, the thickness of that part becomes thinner, and the passivation film 5 is more likely to have defects at its tip, causing a loss of reliability.

Purpose of the Invention The present invention provides a processing method that does not cause defects in the passivation film of a semiconductor device such as the one described above. It is something.

Structure of the Invention The present invention provides a method for manufacturing a semiconductor device, which includes a step of etching an aluminum film formed on a semiconductor substrate into a predetermined electrode shape, and then heat-treating it by a high-speed heating method in a vacuum or an inert gas. As a result, the outermost layer of the aluminum film can be melted instantaneously, and the sharp tip can be made into a gently curved surface. Therefore, a passivation film can be formed on this electrode layer. In this case, the passivation film can be applied with a uniform thickness.

Description of examples The present invention will be described in detail below with reference to Examples.

FIG. 2 is a sectional view of a main part of a semiconductor device showing an embodiment of the present invention in the order of steps. First, as shown in Figure 2(a),
A silicon dioxide film 2 having a thickness of approximately 800 mm is formed on the surface of a silicon substrate 1 by a normal thermal oxidation method. Then, predetermined openings are formed in this silicon dioxide film 2 using a well-known photolithography technique, and then impurities that form a PN junction with the silicon substrate 1 are diffused and introduced through the openings. Region 3 is formed. After this,
An electrode wiring layer 4 of an aluminum film is formed on the diffusion region 3 . At this stage, the ends 6 of the aluminum film electrode wiring layer 4 are almost right-angled and remain sharp immediately after the etching process. Therefore, next, this aluminum film is subjected to heat treatment using a high-speed heating method. An effective method for this heat treatment is to generate infrared rays (heat rays) from a carbon heating element or xenon lamp in a vacuum or in an inert gas such as nitrogen or argon, and heat the material for 10 to 30 seconds with this heat source. . In a vacuum or inert gas, oxidation of aluminum can be prevented, and rapid heating for a short time causes almost no change in the impurity diffusion surface within the semiconductor substrate 1.

When this heat treatment is performed, the aluminum film electrode wiring layer 4 is melted into a gently curved shape as shown in FIG. 2(b). In FIG. 2(C), a silicon dioxide film 6, which is a passivation film, is deposited on top of the passivation film using the well-known CVD technique. It is thick.

3 and 4 are plan views of electrode shapes showing other examples of semiconductor devices obtained by implementing the present invention, and FIG.
-A' sectional view. In this case, the electrode wiring layer is the base layer 8
and an upper aluminum electrode layer 4. For example, if the interval W between the electrode wiring layers is small as in a high-density integrated circuit, a short circuit may occur between adjacent electrode wiring layers. As a means to avoid the occurrence of such defects, the wiring layer has a two-layer structure, the base layer 8 is made of a metal with good etching properties, and the aluminum film electrode layer 4 is placed on top of this.
By forming this, a suitable wiring layer can be formed. in this case,
For the base layer 8, tungsten, titanium, molybdenum, platinum, or a tungsten-titanium alloy is selected. Then, when an aluminum film is laminated and formed on this base layer 8 and this is heat-treated by a high-speed heating method as in the above-mentioned embodiment, only the upper aluminum film melts, and the base layer 8 is heated.
In addition, short-circuit failures between wiring layers due to the aluminum film 4 are less likely to occur. Furthermore, since the surface of the upper aluminum film of the wiring layer is formed into a gently curved surface by rapid heat treatment, when a passivation film is formed on these surfaces, breakage of the passivation film does not occur.

Effects of the Invention As described in detail above, according to the present invention, there is a step of etching an aldinium film formed on a semiconductor substrate into a predetermined electrode shape, and then heat-treating it by a high-speed heating method in a vacuum or an inert gas. Therefore, when the surface of the aluminum film electrode wiring layer has a gently curved shape [;l), and a passivation film is provided on top of this, the passivation film does not cause cracks or other defects at the ends of the wiring, and the semiconductor The reliability of the device is significantly improved.

[Brief explanation of the drawing]

Figure 1 is a sectional view of the main parts of a conventional semiconductor device, Figure 2 (a)
~(C) is a process order sectional view showing an example of this invention, No. 3
FIG. 4 is a plan view of a main part of a semiconductor device obtained in another embodiment of the present invention, and a sectional view thereof taken along line AA'. 1... Semiconductor substrate, 2... Insulating film, 3
... Diffusion region, 4 ... Aluminum film electrode layer, 5 ... Passivation film, 6 ...
・Edge of electrode layer, 7...Crack, 8...
・Substrate layer. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 3 Figure 4

Claims (2)

[Claims] (1) A method for manufacturing a semiconductor device, which includes a step of etching an aluminum film formed on a semiconductor substrate into a predetermined electrode shape, and then heat-treating it by a high-speed heating method in a vacuum or an inert gas. (2) Manufacturing the semiconductor device according to claim 1, wherein the aluminum film is formed on a metal layer selected from tungsten, titanium, molybdenum, and platinum provided on the semiconductor substrate with an insulating film interposed therebetween. Method.