JPS6232609A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To obtain an aluminum wiring whose dimensional shift from a resist pattern is minimized by using an aluminum film and an SiO2 or Si3N4 film having more excellent adhesion as a mask and then by etching the aluminum film. CONSTITUTION:After a contact hole 4 is formed, the aluminum film 6 is sputtered on the entire surface of a wafer and then an insulating film 8 made of an SiO2 or Si3N4 film is sputtered. Next, aluminum wiring patterning is performed by using a photoresist 7 and then the insulating film 8 made of an SiO2 or Si3N4 film is etched using Freon gas by making this photoresist 7 as a mask. After this, the aluminum film 6 is etched by using phosphoric acid or chlorine gas. Finally, the aluminum wiring 6 is formed by removing the photoresist 7.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for forming metal wiring in which dimensional shift from a resist pattern transferred from a photomask is minimized.

[Conventional technology]

Conventionally, there have been steps shown in FIGS. 2 and 3 as a method for forming aluminum wiring in a semiconductor element. In both figures, (ri is an epitaxial layer, (2) is a base diffusion layer, (3 is an emitter diffusion layer, (4) is a contact hole, (5) is an oxide film, (6) is a sputtered aluminum film, ( 7) is a patterned photoresist.

Next, a conventional aluminum etching method will be explained. First, as shown in FIG. 2(a), after opening a contact hole (4), aluminum (6) is sputtered over the entire surface, and aluminum wiring is patterned using photoresist (7). Next, as shown in the figure, the aluminum film (6) is etched with an etching solution such as phosphoric acid while masking the photoresist (7). Then,
The photoresist film (7) is removed and the aluminum wiring (
The formation step 6) is completed (see Figure 0).

Similarly, FIGS. 3A to 3C show the 5th step of dry etching aluminum wiring using a photoresist (7) as a mask and using chlorine gas or the like.

[Problem that the invention seeks to solve]

The conventional etching method for aluminum wiring uses the sputtered aluminum film (6) and the photoresist (7), which has poor adhesion, as a mask as described above, so wet etching using phosphoric acid as shown in Fig. 2 is difficult. , the side etching amount 6υ of the aluminum film (6) becomes large, and the width of the aluminum wiring (6) becomes narrower.Also, as shown in Fig. 6, dry etching using chlorine gas Since etching progresses while the resist edge σD recedes, there is a drawback that the finished dimension of the aluminum wiring (6) becomes narrower.

[Means for solving problems]

This invention was made in order to eliminate the drawbacks of the conventional method as described above. After sputtering the entire surface of an aluminum film, an oxide film (Sin2) or a nitride film (
Sputter an insulating film of (Si3N4) and pattern the aluminum wiring using photoresist.
O2) film or (SisN4) film,
The aluminum film is etched using an insulating film such as a (Si02) film or a (Si3N4) film, which has good adhesion to the aluminum film, as a mask.

[Effect]

According to the present invention, aluminum wiring can be formed with the amount of side etching kept to a minimum through the above-described steps.

[Embodiments of the invention]

Hereinafter, steps according to an embodiment of the present invention will be explained with reference to the drawings. Note that in FIG. 1, the same parts as in FIGS. 2 and 5 are given the same reference numerals, and their redescription will be omitted. In FIGS. 1(a) to 1(d), (8) is an insulating film of oxide film (SiOz) or nitride film (Si3N4) sputtered on sputtered aluminum II (6).

Next, a method for forming aluminum wiring according to an embodiment of the present invention will be explained. Figure 1 (a) K
As shown, after forming the contact hole (4), aluminum 8k <6) was applied to the entire surface of the wafer, followed by (S).
An insulating film (3) of in2) film or (Si3N4) film is sputtered to a thickness of about 1.000λ. Next, the aluminum wiring is patterned using photoresist (7) as shown in the figure Φ). Then, using this photoresist (7) as a mask, the (Sin2) film or (Si3Nn) film is removed. (8) is etched with 7 Leon gas (see Figure 0). Next, the aluminum film (6) is etched with phosphoric acid or chlorine gas. Finally, the photoresist (7) is removed to complete the formation of the aluminum wiring (6) (see figure d).

In the above embodiment, a single layer of aluminum wiring has been described, but the same effects as in the above embodiment can be obtained even when using a double layer of aluminum wiring.

〔Effect of the invention〕

As described above, in this invention, since the aluminum film is etched using a (Sing) film or (Si3N4) film with better adhesion to aluminum as a mask, the aluminum film can be etched with less dimensional shift from the resist pattern. This has the effect of providing wiring.

[Brief explanation of drawings]

1(a) to 1(d) are cross-sectional views showing the process of forming aluminum wiring according to an embodiment of the present invention, and FIG. 2(a)
) to (C) are conventional process diagrams for wet etching aluminum wiring, and Figures 3(a) to (C) are conventional process diagrams for dry etching aluminum wiring. 1) is an epitaxial layer, (2) is a base diffusion layer, (3) is an emitter diffusion layer, (4) is a contact hole,
(5) is an oxide film, (6) is an aluminum film, (7) is a photoresist, and (8) is a 5i02 film or S! 3Na1
91 absolute R film. Note that the same reference numerals in each figure indicate the same or corresponding parts. Agent Patent Attorney Tadashi Sato Figure 1 111\--1 111\--I 5C Pimarui and January Beauty 2nd Cause $1

Claims (1)

[Claims] (1) In the method of forming aluminum wiring on a wafer, a sputtered aluminum film is coated with (SiO_2) or (Si_3N_), which has good adhesion to the aluminum.
4) sputtering an insulating film, then patterning the aluminum wiring on this insulating film with photoresist, and then etching the sputtered aluminum film and the insulating film using the photoresist as a mask. A method for manufacturing a featured semiconductor device.