JP3049872B2 - Method for manufacturing semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a semiconductor device, and more particularly to a method for manufacturing a metal wiring formed by plating.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 3A, a method of manufacturing a semiconductor device having a multi-layered metal plating wiring is applied to a semiconductor substrate 41, which has completed a required element forming step, by applying an adhesive force to an underlying film. The first is to strengthen and to be the current path for plating.
And a first plating base film 43 is formed as a base film for forming a metal plating wiring thereover. Thereafter, as shown in FIG. 3B, electrolytic plating is performed using the first photoresist pattern 44 as a mask to form a first metal plating wiring 45 on the first plating base film 43. After that, as shown in FIG. 3C, after the first photoresist pattern 44 is peeled off, the first metal conductive film 4 is formed using the first metal plating wiring 45 as a mask.
The unnecessary portion 2 is removed by etching, and each metal plating wiring is insulated and separated. Thereafter, as shown in FIG. 3D, in order to strengthen the adhesion between the first metal plating wiring 45 and the interlayer insulating film formed thereover, the first metal adhesive film having strong adhesion to both materials. After 46 is applied to the entire surface, the first metal adhesive film 46 is formed only on the surface of the first metal plating wiring 45 by an etching method using the second photoresist pattern 47 as a mask. Thereafter, as shown in FIG. 3E, a second photoresist pattern 47 is formed.
After peeling off, an interlayer insulating film 48 is formed, and an opening window for connecting the first metal plating wiring 45 and the second metal plating wiring 51 is formed by a normal etching method. A second metal conductive film 49, a second plating base film 50, a second metal plating wiring 51, and a second metal adhesive film 52 are formed. Hereinafter, a multilayer metal plated wiring was formed in the same manner to manufacture a semiconductor device.

[0003]

In the above-mentioned conventional method for manufacturing a semiconductor device, a metal adhesive film for enhancing the adhesion between a metal plating wiring and an interlayer insulating film is formed by etching using a photoresist pattern. Due to the formation, in places where the distance between adjacent metal plating wirings is extremely narrow, etching residue is likely to occur at the lower part of the step caused by the lower layer wiring etc., and each metal plating wiring remains electrically short-circuited There was a problem that it was easy to become.

[0004]

According to a method of manufacturing a semiconductor device of the present invention, after a required element forming step for a semiconductor substrate is completed, a first opening window is formed in a first photoresist by patterning and plating is performed. Exposing a base film in a region where a metal is to be grown; applying a polyimide resin while leaving the first photoresist pattern; planarizing the surface; and removing the upper layer by etching to remove the first layer.
Leaving a polyimide resin in the opening window, applying and forming a second photoresist pattern, forming a second opening window in a region smaller than the first opening window, and exposing the polyimide resin; Removing all of the polyimide resin using the photoresist pattern as a mask, and forming a metal plating wiring in the first opening window by plating;
A step of applying a metal adhesive film for enhancing the adhesion between the metal plating wiring and the interlayer insulating film over the entire surface of the substrate while leaving the second photoresist pattern; Removing the second photoresist pattern and forming a metal film only on the surface of the metal plating wiring.

[0005]

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

FIGS. 1A to 1F are sectional views showing a first embodiment in which the present invention is applied to metal plating wiring of a tape carrier type integrated circuit in the order of manufacturing steps. That is, in this embodiment, an element chip is formed on a semiconductor substrate 1 on which required elements are formed, and each element is provided with a plurality of metal plating wirings, here, metal plating wirings using gold. First, FIG.
As shown in (A), the first metal conductive film 2 serving as a current path when plating is formed on the entire surface of the semiconductor substrate 1 after forming an element (not shown) with a thickness of about 0.3 μm. Of titanium is deposited. A first plating base film 3 serving as a base film for plating formed by a selective etching method, a lift-off method, or the like is formed on the titanium film.
It has a two-layer structure of a titanium film (0.1 μm thick) for increasing the adhesion strength to the base and a platinum film (0.1 μm thick) for preventing diffusion of gold and growing gold-plated wiring. It has become. Next, as shown in FIG. 2 (B), after forming a first photoresist pattern 4 having a thickness of about 3.0 μm exposing the first plating base film 3 by ordinary patterning, the film is formed. After applying a polyimide resin to a thickness of about 8.0 μm and flattening the substrate surface, the polyimide resin is uniformly etched to a thickness of the first photoresist pattern 4 by an etch-back method. The polyimide resin 5 is formed only in the opening region.
Thereafter, as shown in FIG. 1C, the polyimide resin 5 is entirely removed by etching using a second photoresist pattern 6 having a thickness of about 3.0 μm, which is formed by patterning in a conventional manner, as a mask. Is exposed. Here, the opening area of the second photoresist pattern 6 is smaller than the opening area of the first photoresist pattern 4,
Its cross-sectional shape is overhanging. Then, FIG.
As shown in (D), the semiconductor substrate 1 is immersed in a gold plating solution,
The plating is performed by passing a current between the first metal conductive film 2 and the anode electrode plate on the plating apparatus side as a current path to perform plating.
A gold plating layer, that is, a film thickness of about 1.0 is formed on the first plating base film 3.
A metal plating wiring 7 having a thickness of μm is formed, and a metal adhesive film 8 serving as an adhesive layer with an upper interlayer insulating film is deposited on the entire surface while leaving the first photoresist pattern 4 and the second photoresist pattern 6. I do. Here, as the metal adhesive film, a titanium film (approximately 0.1 μm thick) having extremely strong adhesion to both the metal plating wiring and the interlayer insulating film is used. Since the cross-sections of the first photoresist pattern 4 and the second photoresist pattern 6 have an overhang shape, the metal adhesive film 8 is formed on the first metal plating wiring 7 and the second metal pattern. On the photoresist pattern 6 in a divided state. Next, utilizing the fact that the metal adhesive film 8 is divided as shown in FIG. 1E, the unnecessary portion is removed together with the first photoresist pattern 4 and the second photoresist pattern 6 by a lift-off method. Then, a first metal adhesive film 8 is formed. Here, since the first metal adhesive film 8 is formed only on the first metal plating wiring 7, an etching residue may occur as compared with the conventional method of forming using a photoresist pattern. There is no electrical short circuit between adjacent metal plated wirings. After that, as shown in FIG.
, And the metal plating wirings are insulated and separated from each other, a silicon oxide film 9 as an interlayer insulating film is formed, and an opening window for connecting the first metal plating wiring 7 and the second metal plating wiring 12 is formed. Is formed by a normal etching method. Thereafter, the second metal conductive film 1 is formed in the same manner as described above.
0, second plating base film 11, second metal plating wiring 1
2. If the second metal adhesive film 13 is formed, a semiconductor device using the present invention is completed. Therefore, according to this method, the metal adhesive film can be easily and reliably formed only on the metal plating wiring.

Here, other metals may be used for the metal conductive film, the plating base film, and the metal adhesive film, and a metal other than gold can be used for the metal plating wiring.

FIGS. 2A to 2F are cross-sectional views showing a second embodiment of the present invention in the order of manufacturing steps. FIG. 2 (A)
In the first method, a titanium film having a thickness of about 0.3 μm, which serves as a current path when plating is performed, is strengthened over the entire surface of the semiconductor substrate 21 after completion of an element (not shown) and serves as a current path when plating. A gold film having a thickness of about 0.1 μm is further deposited thereon as a first plating base film 23 as a base film for forming a metal plating wiring. ing. On the upper layer, a first positive photoresist pattern 24 having a thickness of about 3.0 μm, which is a part of a mask for plating, is formed, and a window is formed in a region where a metal plating wiring is formed. The opening is opened, and a part of the first plating base film 23 is exposed. Next, as shown in FIG. 2B, a polyimide resin having a thickness of about 8.0 μm is applied to flatten the surface of the substrate, and then the polyimide film is etched up to the thickness of the first positive photoresist pattern 24 by an etch-back method. The resin is uniformly etched, and a polyimide resin 25 is formed only in the opening region of the first positive photoresist pattern 24. Thereafter, as shown in FIG. 2C, a second positive type photoresist pattern 26 is formed by an ordinary method. Here, utilizing the solubility of the polyimide resin in the developing solution of the positive photoresist, the polyimide resin 25 is simultaneously etched away in the developing step to expose the first plating base film 23.

Here, the opening area of the second positive photoresist pattern 26 is smaller than the opening area of the first positive photoresist pattern 24, and its cross-sectional shape is overhanging. Thereafter, as shown in FIG. 2D, the semiconductor substrate 21 is immersed in a gold plating solution, and a current is caused to flow between the first metal conductive film 22 and a positive electrode plate on the plating apparatus side as a current path to perform plating. By doing, the first
A gold plating layer in a region where the plating base film 23 is exposed,
That is, the first metal plated wiring 27 having a thickness of about 1.0 μm is formed. Thereafter, a metal adhesive film 28 serving as an adhesive film with an interlayer insulating film is applied to the entire surface while leaving the first photoresist pattern 24 and the second photoresist pattern 26. Here, as the metal adhesive film 28, a mixed film (thickness: about 0.1 μm) of titanium and tungsten having extremely strong adhesion to both the metal plating wiring and the interlayer insulating film is used. Here, since the cross sections of the first positive photoresist pattern 24 and the second positive photoresist pattern 26 are overhanging, the metal adhesive film 28
The first metal plating wiring 27 and the second positive type photoresist pattern 26 are applied in a divided state. Thereafter, as shown in FIG. 2E, a first metal adhesive film 28 is formed only on the first metal plated wiring 27 by using a lift-off method in the same manner as in the first embodiment. Then, using the first metal plating wiring 27 as a mask, the unnecessary first plating base film 23 is made of an aqua regia aqueous solution, and the first metal conductive film 2 is removed.
2 is etched away with a hydrofluoric acid aqueous solution to electrically insulate and separate each metal plating wiring. Thereafter, a silicon oxide film 29 as an interlayer insulating film is formed, and an opening window for connecting the first metal plating wiring 27 and the second metal plating wiring 31 is formed by a normal etching method. Thereafter, the first metal conductive film 30, the second plating base film 31, the second metal plating wiring 32, and the second metal adhesive film 33 are formed in the same manner as described above, and the semiconductor device using the present invention is formed. Is completed.

Therefore, according to this method, the metal adhesive film can be easily and reliably formed only on the metal plating wiring. Further, here, other metals may be used for the metal conductive film, the plating base film, and the metal adhesive film, and a metal other than gold can be used for the metal plating wiring.

[0011]

As described above, according to the present invention, a metal adhesive film for strengthening the adhesion between a metal plating wiring and an interlayer insulating film thereover is formed by lift-off using a photoresist used for plating. Because it is formed by the method, it is formed only on the metal plating wiring, and since the photoresist is overhanging, it is possible to easily remove the unnecessary part of the metal adhesive film, and the metal plating This has the effect of preventing a failure in which a metal adhesive film remains between wirings and an electrical short circuit occurs.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention in the order of manufacturing steps.

FIG. 2 is a sectional view showing a second embodiment of the present invention in the order of manufacturing steps.

FIG. 3 is a cross-sectional view showing a conventional technique in the order of manufacturing steps.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 semiconductor substrate on which element has been formed 2 first metal conductive film 3 first plating base film 4 first photoresist pattern 5 polyimide resin 6 second photoresist pattern 7 first gold-plated wiring 8 first metal Adhesive film 9 Silicon oxide film 10 Second metal conductive film 11 Second plating base film 12 Second metal plated wiring 13 Second metal adhesive film 21 Element-formed semiconductor substrate 22 First metal conductive film 23 1 plating underlayer 24 first positive photoresist pattern 25 polyimide resin 26 second positive photoresist pattern 27 second plating underlayer 28 first metal adhesive film 29 silicon oxide film 30 second metal conductive Film 31 second plating base film 32 second metal plating wiring 33 second metal adhesive film 41 element-formed semiconductor substrate 42 first metal Conductive film 43 first plating base film 44 first photoresist pattern 45 first metal plating wiring 46 first metal adhesive film 47 second photoresist pattern 48 interlayer insulating film 49 second metal conductive film 50 2 plating base film 51 second metal plating wiring 52 second metal adhesive film

──────────────────────────────────────────────────の Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 21/3205 H01L 21/321 H01L 21/3213 H01L 21/768 H01L 21/28-21/288 H01L 21 / 44-21/445 H01L 29/40-29/51 H01L 29/872 H01L 21/027 H01L 21/30 H01L 21/46

Claims (1)

(57) [Claims] A step of patterning a first opening window in a first photoresist after exposing a required element forming step on the semiconductor substrate, and exposing a base film in a region where a metal is grown by plating; A polyimide resin is applied while leaving the first photoresist pattern, the surface is flattened, and then the upper layer portion is removed by etching.
Leaving a polyimide resin in the opening window of step (a), applying a second photoresist pattern to form a second opening window in a region smaller than the first opening window, and exposing the polyimide resin; A step of removing all the polyimide resin using the resist pattern as a mask, a step of forming a metal-plated wiring in the first opening window by plating, and a step of strengthening adhesion between the metal-plated wiring and the upper interlayer insulating film. A step of applying a metal adhesive film to the entire surface of the substrate while leaving the second photoresist pattern, and removing an unnecessary portion of the metal adhesive film, the second photoresist pattern, and the first photoresist pattern to form a metal plating wiring. Forming a metal film only on the surface of the semiconductor device.