JPH04255225A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To avoid the overhanging of a layer insulating film by a method wherein, after the formation of a silicon oxide film on a plating conductive film using a photoresist film as a mask, the photoresist film is removed to form a metallic film using the silicon oxide film as a mask. CONSTITUTION:After the formation of a silicon oxide film 2 on a silicon substrate 1, a titanium containing tungsten film 4 is successively deposited on the film 2 so as to form a plating conductive film. Next, a photoresist film 5 is coated on the gold film 4 to be patterned later. Next, the substrate 1 is immersed in the water solution comprising hydrogen silicon fluoride solution saturated with silicon oxide melted therein and then boric acid solution is continuously added to the gold film 4 so as to form a silicon oxide film 6 while being filtered. Next, the photoresist film 5 is removed to expose the surface of the gold film 4. Finally, a gold plating film 7 is formed using the silicon oxide film as a mask and then the silicon oxide film 6, the gold film 4 and the titanium containing tungsten film 3 are removed.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device, and more particularly to a method of manufacturing a semiconductor device having metal wiring.

0002

[Prior Art] A conventional method for manufacturing a semiconductor device is shown in FIG.
As shown in a), a silicon oxide film 2 is formed on a silicon substrate 1, and a film with a thickness of 0.125 mm is formed on the silicon oxide film 2.
μm titanium-containing tungsten film 3 and thickness 0.02μ
m palladium films 8 are sequentially deposited by sputtering. Next, a 1μ photoresist film 5 is placed on the palladium film 8.
The photoresist film 5 is coated to a thickness of m and patterned using photolithography.

Next, as shown in FIG. 3B, a gold plating film 7 is formed to a thickness of 0.85 μm on the palladium film 8 by electroplating using the photoresist film 5 as a mask.

Next, as shown in FIG. 3C, after removing the photoresist film 5, the palladium film 8 and the titanium-containing tungsten film 3 are sequentially etched and removed using the gold plating film 7 as a mask. tungsten-containing film 3,
A metal wiring is formed by laminating a palladium film 8 and a gold plating film 7 (for example, using Solid State Technology).
ogy), December 1983 issue, page 137].

[0005]

[Problems to be Solved by the Invention] However, in the conventional semiconductor device manufacturing method described above, as shown in FIG. Since θ becomes an obtuse angle, when a metal plating film is subsequently formed by electroplating, the cross section of the metal plating film becomes an inverted trapezoid as shown in FIG. 3(b), and an interlayer insulating film is formed on the surface including the metal wiring. When it is formed, it has an overhanging shape, which causes a problem of disconnection or short-circuiting of the upper layer wiring formed on the interlayer insulating film.

Furthermore, if the plating solution is alkaline, the photoresist film may peel off or be etched.
There is a problem in that a desired wiring pattern cannot be formed due to pattern distortion.

[0007]

[Means for Solving the Problems] A method for manufacturing a semiconductor device of the present invention includes a step of forming a conductor film for plating on an insulating film provided on a semiconductor substrate, and a photoresist film on the conductor film for plating. and a step of depositing a silicon oxide film on the plating conductor film by immersing the semiconductor substrate in a saturated solution of silicon oxide dissolved in an aqueous solution of hydrofluoric acid. , forming a metal plating film on the plating conductor film by electroplating after removing the photoresist film; and forming the plating conductor film using the metal plating film as a mask after removing the silicon oxide film. The structure includes a step of etching and removing the metal wiring to form a metal wiring.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained with reference to the drawings.

FIGS. 1(a) to (c) and FIGS. 2(a) to (c)
) are cross-sectional views of a semiconductor chip shown in the order of steps for explaining an embodiment of the present invention.

First, as shown in FIG. 1(a), a silicon oxide film 2 is formed on a silicon substrate 1, and then a 0.2 μm thick titanium-containing tungsten film 3 and a 0.2 μm thick titanium-containing tungsten film 3 are formed on the silicon oxide film 2. Gold films 4 having a thickness of 0.05 μm are sequentially deposited by sputtering to form a conductor film for plating.

Next, as shown in FIG. 1(b), a photoresist film 5 is coated on the gold film 4 to a thickness of 1.8 to 2.0 μm, and the photoresist film is formed using photolithography. Pattern 5.

Next, as shown in FIG. 1(c), the concentration of about 3
Silicon oxide was dissolved and saturated in a 3% hydrofluoric acid solution, and the silicon substrate 1 was immersed in an aqueous solution maintained at a temperature of 35°C, and about 0.1 mol/liter of silicon oxide was placed on the gold film 4. A silicon oxide film 6 with a thickness of approximately 1.5 μm is added while continuously adding a boric acid aqueous solution and constantly filtering.
form.

Next, as shown in FIG. 2(a), the photoresist film 5 is removed using an organic solvent to expose the surface of the gold film 4.

Next, as shown in FIG. 2(b), the silicon oxide film 6 is used as a mask to form a film with a thickness of about 1 μm by electroplating.
A gold plating film 7 having a thickness of m is formed.

Next, as shown in FIG. 2C, after removing the silicon oxide film 6 with a hydrofluoric acid aqueous solution, the gold film 4 is removed by ion milling using the gold plating film 7 as a mask.
Then, the titanium-containing tungsten film 3 is etched and removed by reactive ion etching to form a metal wiring consisting of a laminated layer of the titanium-containing tungsten film 3, the gold film 4, and the gold plating film 7.

[0016] Here, in the metal wiring, the side walls of the gold plating film 7 form an obtuse angle with respect to the substrate surface, so even if an interlayer insulating film is formed, an overhanging shape does not occur, and the metal wiring does not have an overhanging shape on the interlayer insulating film. It is possible to prevent disconnections and short circuits in the upper layer wiring provided in the upper layer.

Furthermore, since a silicon oxide film is used as a mask during electroplating, there is an advantage that the silicon oxide film can be prevented from being peeled off or etched even when an alkaline plating solution is used.

As the conductor film for plating, a titanium nitride film may be used instead of the titanium-containing tungsten film 3, and a platinum film may be used instead of the gold film 4.

[0019]

As explained above, in the present invention, a silicon oxide film is formed on a plating conductor film using a patterned photoresist film as a mask, and then the photoresist film is removed and the silicon oxide film is masked. By forming a metal plating film as a metal plating film, the side walls of the metal wiring including the metal plating film form an obtuse angle with respect to the substrate surface, thereby preventing the interlayer insulating film formed thereon from having an overhanging shape. This has the effect of suppressing disconnections and short circuits in the wiring formed in the upper layer.

Furthermore, since the silicon oxide film is used as a mask during plating, it is possible to prevent peeling of the photoresist film and thinning of the pattern that would otherwise occur when using a photoresist film.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a semiconductor chip shown in order of steps for explaining an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a semiconductor chip shown in order of steps for explaining an embodiment of the present invention.

FIG. 3 is a cross-sectional view of a semiconductor chip shown in order of steps for explaining a conventional method for manufacturing a semiconductor device.

[Explanation of symbols]

1 Silicon substrate 2 Silicon oxide film 3 Tungsten film containing titanium 4 Gold film 5 Photoresist film 6 Silicon oxide film 7 Gold plating film 8 Palladium membrane

Claims (2)

[Claims] 1. A step of forming a conductor film for plating on an insulating film provided on a semiconductor substrate, a step of applying and patterning a photoresist film on the conductor film for plating, and a step of forming a conductor film for plating on an insulating film provided on a semiconductor substrate, and a step of applying and patterning a photoresist film on the conductor film for plating. A step of immersing the semiconductor substrate in a saturated solution of silicon oxide dissolved in an aqueous solution and depositing a silicon oxide film on the conductor film for plating, and after removing the photoresist film, electroplating the a step of forming a metal plating film on a conductor film for plating, and a step of removing the silicon oxide film and etching and removing the conductor film for plating using the metal plating film as a mask to form a metal wiring. A method of manufacturing a semiconductor device, comprising: 2. The method of manufacturing a semiconductor device according to claim 1, wherein the conductor film for plating has a two-layer structure in which a gold film or a platinum film is deposited on a titanium-containing tungsten film or a titanium nitride film.