JPH03198342A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To prevent generation of etching residue and reattachment of foreign matter on a bump electrode surface, and sufficiently secure adhesion between a bump electrode and a semiconductor substrate, by providing a process for forming a wiring for elements and a wiring for electroplating. CONSTITUTION:After a silicon nitride film 2 and an aluminum film 3 are formed on a semiconductor substrate 1, a first photoresist pattern 4 is formed. By etching method using the pattern 4 as a mask, unnecessary parts of the film 3 are eliminated, and a wiring for elements necessary for a semiconductor device is formed. Said wiring for elements is formed as an aluminum wiring 3a, and a wiring 3b for electroplating is formed in a dicing line region 1. After electroplating process, the unnecessary wiring 3b is eliminated, and each protruding electrode is subjected to dielectric isolation. Hence electroplating is enabled by using polyimide resin 9, which is a final protecting film, as a mask. Thereby generation of etching residue and reattachment of foreign matter on the surface of a gold bump electrode 11 can be prevented, and adhesion between the electrode 11 and the substrate 1 can sufficiently be secured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method of manufacturing a semiconductor device, and particularly to a method of manufacturing a semiconductor device having protruding electrodes.

[Conventional technology]

Generally, in a tape carrier type semiconductor device, a protruding metal electrode is provided on the main surface of a semiconductor substrate.

Conventionally, in the manufacturing method of a semiconductor device having this type of protruding electrode, after completing all the necessary element formation steps and wiring formation steps on the semiconductor substrate, a new metal film is deposited on the entire surface of the substrate and this is electrolyzed. This is configured as a current path during plating, and then a base film is formed on this metal film for the protruding electrode formation area using a lift-off method, etc., and a photoresist or the like is used as a mask, and the metal film is used as a current path. A protruding electrode is formed in the protruding electrode formation area by electrolytic plating, and then the unnecessary metal film, which is a current path during electrolytic plating, is completely removed using the protruding electrode as a mask, and then a protective film is applied to the entire surface of the substrate. The method used was to apply the protective film to the surface of the protective film, and then open only the protruding electrode portions to form the final protective film.

[Problem to be solved by the invention]

The conventional method for manufacturing a semiconductor device having a protruding electrode as described above is a method in which a protective film is applied after the protruding electrode is formed, and the protective film on the protruding electrode portion is etched away using a photoresist or the like as a mask to form a final protective film. As a result, etching residue during the etching process and foreign matter re-adhering during the photoresist stripping process are likely to occur on the surface of the protruding electrode, which can significantly reduce the adhesion strength between the lead and the protruding electrode during bonding. There is a drawback.

Furthermore, in order to ensure sufficient adhesion strength between the protruding electrode and the semiconductor substrate, it is necessary to create a structure in which the periphery of the protruding electrode surface is covered with a final protective film. The drawback is that it is very difficult to produce well and stably.

[Means to solve the problem]

The method for manufacturing a semiconductor device of the present invention includes a step of forming a metal film for wiring on a semiconductor substrate and then patterning it to form wiring for an element and wiring for electrolytic plating, and forming a protective film on the entire surface and then patterning it. a step of removing a protective film from a protruding electrode formation region of the element wiring and a connection film formation region for electrically connecting the element wiring and the electrolytic plating wiring; and the protrusion from which the protective film has been removed. A step of forming a barrier film in the electrode formation region and a connection film formation region, a step of forming a first photoresist pattern on this barrier film in the protrusion electrode formation region, and a step of forming a second photoresist pattern after forming a protective film on the entire surface. Patterning using a photoresist pattern,
exposing a part of the upper part of the first photoresist pattern; removing the second photoresist pattern and simultaneously removing the first photoresist pattern to expose the barrier film; A step of forming a protruding electrode on the barrier film exposed by electrolytic plating using a protective film as a mask, and a step of selectively removing the electrolytic plating wiring to release a short circuit between the protruding electrodes after forming the protruding electrode. It consists of:

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIGS. 1(a) to (j) and FIG. 2 are diagrams for explaining a first embodiment in which the present invention is applied to the formation of protruding electrodes of a tape carrier type integrated circuit, and FIG. 2 is a diagram showing the manufacturing process. 1(a) to 1(j) are cross-sectional views of the semiconductor chip taken along the line AA' in the order of manufacturing steps.The following will explain the steps in the order of the manufacturing steps.

First, as shown in FIG. 1(a), elements are formed on a semiconductor substrate 1 made of silicon. Next, an aluminum film 3 with a thickness of about 0.8 μm is sputtered onto the device region where the silicon nitride M2 with a thickness of about 1 μm is formed and on the dicing line region I with a width of about 200 μm where the surface of the semiconductor substrate 1 is exposed. form.

Next, as shown in FIG. 1(b), a first photoresist pattern 4 is formed in a desired thickness and shape, and unnecessary portions of the aluminum film 3 are removed by an etching method using this as a mask. Form wiring for elements necessary for the device. This element wiring is formed as an aluminum wiring 3a including a protruding electrode forming region (2). At the same time, electrolytic plating wiring 3b is formed in the dicing line region I.

Next, as shown in FIG. 1(c), after peeling off the first photoresist pattern 4, a silicon oxide film 5 as a protective film is grown on the entire surface to a thickness of about 0.5 μm. Using the second photoresist pattern 6 patterned to the desired thickness and shape as a mask, the silicon oxide film 5 is formed in the protruding electrode formation region (2) and the connection film formation region (3) for connecting the aluminum wiring 3a and the electrolytic plating wiring 3b. Remove by etching.

Next, as shown in FIG. 1(d), a metal film 7, which will serve as a barrier film when growing a plating layer, is deposited on the substrate surface while leaving the second photoresist pattern 6 intact. Here, the metal film 7 includes a platinum film with a thickness of 0.1 μm for the purpose of preventing gold from diffusing into the underlying layer, and a platinum film with a thickness of 0.1 μm for the purpose of strengthening the adhesion between the platinum film and the base layer. It has a two-layer structure of titanium film.

Next, as shown in FIG. 1(e), the second photoresist pattern 6 is peeled off, and at the same time, unnecessary portions of the metal film 7 are removed by a lift-off method, and then the metal film 7 is heated in a nitrogen atmosphere at 400°C for 60 minutes. By heat treatment, a barrier H7a is formed in the protruding electrode formation region (■), and a barrier H7a is formed in the connection film formation region (■).
A connection film 7b for electrolytic plating wiring is formed. Therefore, the aluminum wiring 3a is electrically connected to the electrolytic plating wiring 3b by the connection film 7b.

Next, as shown in FIG. 1(f), a photoresist is applied to a thickness of about 5 μm, and the barrier film 7a in the protruding electrode formation region
A third photoresist pattern 8 patterned into a desired shape is formed only inside the photoresist pattern.

Next, as shown in FIG. 1(g), a final protective film of polyimide resin 9 is applied to a thickness of approximately 10 μm, and a fourth photoresist pattern 10 patterned to the desired thickness and shape is used as a mask. Then, the third photoresist pattern 8
The polyimide resin 9 in the upper part of the area and the dicing area is removed. Here, a part of the upper layer of the third photoresist pattern 8 is exposed through the opening of the polyimide resin 9.

Next, as shown in FIG. 1(h), the fourth photoresist pattern 10 is removed and at the same time, the third photoresist pattern 8 is also removed to expose a part of the barrier film 7a.

Here, the cross-sectional shape of the polyimide resin 9 in the protruding electrode forming region (2) has an overhanging shape. Note that the planar structure in FIG. 2 shows the completed state of the process in FIG. 1(h).

Next, as shown in FIG. 1(i), the entire substrate is immersed in a gold plating solution, and a current is passed between the semiconductor substrate 1 and the anode electrode plate installed on the gold plating equipment side, so that all the protruding electrodes 11 are protruded. Electrolytic plating is performed until a thickness of 15 to 30 μm is formed on the barrier film 7a in the electrode formation region (2). Here, the fully protruding electrodes 11 are grown according to the cross-sectional shape of the polyimide resin 9 used as a mask. Therefore, the cross-sectional structure is held down to the barrier film 7a side by the polyimide resin 9, and the adhesion strength to the base side becomes extremely strong.

Next, as shown in FIG. 1<j), the silicon oxide film 5 in the dicing line region I is removed by etching using the polyimide resin 9 and all the protruding electrodes 11 as masks, and then the connecting film 7b is used as an etching stopper. By removing the electrolytic plating wiring 3b and insulating and separating the dicing line region I and the aluminum wiring 3a, all the protruding electrodes 11
A semiconductor device having the following is completed.

In this way, in the first embodiment, the electrolytic plating wiring 3b, which is formed at the same time as the semiconductor element wiring, is used in the current path during electrolytic plating, and unnecessary electrolytic plating in the dicing line area processing is performed after the electrolytic plating process. Since each protruding electrode is insulated and separated by simply removing the wiring 3b, electrolytic plating can be performed using the final protective film as a mask, eliminating etching residue and foreign matter on the surface of all protruding electrodes 11. It is possible to fundamentally prevent the occurrence of redeposition, etc. of In addition, polyimide resin 9, which is the final protective film,
Due to the overhanging cross-sectional shape, it is possible to ensure sufficient adhesion strength between the entire protruding electrode 11 and the semiconductor substrate 1.

3(a) to (h) are cross-sectional views shown in the order of manufacturing steps for explaining the second embodiment of the present invention, and are cross-sectional views taken at the same position as the first embodiment. .

First, as shown in FIG. 3(a), similarly to the first embodiment, a dicing line region I is formed in which the silicon nitride film 22 is removed to expose the surface of the semiconductor substrate 21, and the silicon nitride film 22 is formed. An aluminum film is deposited on the entire surface of the element region. Next, unnecessary portions of the aluminum film are removed using the first photoresist pattern 24 formed in the desired thickness and shape as a mask, and the aluminum wiring 23a including the protruding electrode formation region 2 and the electrolytic plating wiring 23b are formed. Form.

Next, as shown in FIG. 3(b), a positive photoresist is coated to a thickness of approximately 5 μm and patterned into a desired shape within the protruding electrode formation region (■) and the connection film formation region (■).
A photoresist pattern 25 is formed.

Next, as shown in FIG. 3(c), a final protective film of polyimide resin 26 is applied to a thickness of approximately 10 μm, and a third photoresist pattern 27 patterned to the desired thickness and shape is used as a mask. Then, the polyimide resin 26 in the dicing line region I is removed.

Next, as shown in FIG. 3(d), after peeling off the third photoresist pattern 27, a fourth photoresist pattern 28 is re-formed to the desired thickness and shape, and this is used as a mask to form the second photoresist pattern. The polyimide resin 26 in a part of the photoresist pattern 25 is removed by etching with a hydrazine-based chemical solution. Here, by utilizing the solubility of the positive type photoresist in hydrazine-based chemical solution, the second photoresist pattern 25 is also removed by etching at the same time to expose the aluminum wiring 23a in the protruding electrode forming region (2).

Next, as shown in FIG. 3(e), a metal film 29 is deposited on the substrate surface, leaving the fourth photoresist pattern 28 and serving as a barrier film when plating is grown. Here, the metal film 29 is a two-layer film of titanium and platinum, as in the first embodiment.

Next, as shown in FIG. 3(f), at the same time as the fourth photoresist pattern 28 is peeled off, unnecessary portions of the metal film 29 are removed using a lift-off method, and then heat treatment is performed for 60 minutes in a nitrogen atmosphere at 400°C. , a barrier film 29a is formed in the protruding electrode forming region (2), and a connecting film 29b is formed in the connecting film forming region (2).

Next, as shown in FIG. 3 (g>), the entire substrate is immersed in a gold plating solution, and a current is passed between the semiconductor substrate 21 and the anode electrode plate installed on the plating equipment side to remove all the protruding electrodes 30a and the small gold protrusions. Electrolytic plating is performed until the electrode 30b is formed to a thickness of 15 to 30 μm.

After electrolytic plating is completed, all the electrolytic plating wiring 23b in the dicing line area I is removed in the same manner as in the first embodiment, and the dicing line area I and the aluminum wiring 23a are insulated and separated, resulting in the result shown in FIG. 3(h). All protruding electrodes 30
A semiconductor device having a metal protrusion electrode 30b and a metal protrusion electrode 30b is completed.

In this second embodiment as well, electrolytic plating is performed using the final protective film as a mask, so that it is possible to prevent etching residues and foreign matter from re-adhering to the surface of all protruding electrodes 30a, and to Due to the overhanging cross-sectional shape of the polyimide resin 26 serving as the protective film, sufficient adhesion strength between the all-projecting electrodes 30a and the semiconductor substrate 21 can be ensured.

In addition, in this second embodiment, since the second photoresist pattern 25 formed in the protruding electrode formation region 2 is of a positive type, when patterning the polyimide resin 26,
It is now possible to simultaneously perform etching and removal using a hydrazine-based chemical solution, and the fourth photoresist pattern 28
It became possible to form the barrier film 29a by only etching pattern formation and lift-off method. Furthermore, the small gold protrusion electrode 30b formed at the same time as the electrolytic plating is used when bonding the tape carrier and the semiconductor device by pressure bonding.
It can also serve to prevent the leads of the tape carrier from coming into contact with the edges of the semiconductor device.

In the above embodiments, the case where gold plating was used to form the protruding electrodes was explained, but the protruding electrodes may be formed by plating with other metals. [Effects of the Invention] As explained above, the present invention After patterning the metal film formed on the semiconductor substrate to form element wiring and electrolytic plating wiring, and forming a protective film exposing the protruding electrode formation area and connection film formation area, a barrier film is applied to these areas. Electrolytic plating is performed using the electrolytic plating wiring as a current path on only the protruding electrode forming area or on the protruding electrode forming area and the connecting film forming area, forming a protruding electrode made of a metal plating film, By selectively removing wiring and insulating and separating the wiring necessary for semiconductor devices from the semiconductor substrate, it is only necessary to remove the wiring for electrolytic plating after electrolytic plating is completed, and the process of forming protruding electrodes is extremely simple. It will be easy. Furthermore, since the final stage of the protective film is formed before forming the protruding electrodes, etching residue of the protective film or re-adhesion of foreign matter will not occur on the surface of the protruding electrodes. It is possible to ensure sufficient adhesion strength between the two. Further, since the final protective film, which serves as a mask during electrolytic plating, has an overhanging cross-sectional shape, sufficient adhesion strength between the protruding electrode and the semiconductor substrate can be ensured easily. Therefore, a semiconductor device having a protruding electrode can be manufactured reliably and stably.

[Brief explanation of drawings]

1(a) to (j) are cross-sectional views of a semiconductor chip shown in the order of steps for explaining the first embodiment of the present invention, FIG. 2 is a plan view of the first embodiment in the middle of the process, Figure 3 (a
) to (h) are cross-sectional views of a semiconductor chip shown in the order of steps for explaining a second embodiment of the present invention. 1... Semiconductor substrate, 2... Silicon nitride film, 3...
・Aluminum film, 3a...Aluminum wiring, 3b
... Wiring for electrolytic plating, 4... First photoresist pattern, 5... Silicon oxide film, 6... Second photoresist pattern, 7... Metal film, 7a...
Barrier film, 7b... Connection film, 8... Third photoresist pattern, 9... Polyimide resin, 10...
Fourth photoresist pattern, 11... Gold protrusion electrode, 21... Semiconductor substrate, 22... Silicon nitride film,
23a... Aluminum wiring, 23b... Electrolytic plating wiring, 24... First photoresist pattern,
25... second photoresist pattern, 26...
Polyimide resin, 27... Third photoresist pattern, 28... Fourth photoresist pattern, 29
...Metal film, 29...Barrier film, 29b...Connection film, 30a...Gold protrusion electrode, 30b...Small gold protrusion electrode.

Claims (1)

[Claims] A process of forming a metal film for wiring on a semiconductor substrate and then patterning it to form element wiring and electrolytic plating wiring, and forming a protective film on the entire surface and patterning it to form a protruding electrode formation area of the element wiring. a step of removing a protective film in a connection film forming area for electrically connecting the element wiring and the electrolytic plating wiring; and a step of removing a barrier film in the protruding electrode forming area and the connecting film forming area from which the protective film has been removed. a step of forming a first photoresist pattern on the barrier film in the protruding electrode formation region; a step of forming a protective film over the entire surface and then patterning it using a second photoresist pattern; a step of exposing a part of the upper part of the first photoresist pattern, a step of removing the first photoresist pattern at the same time as removing the second photoresist pattern to expose the barrier film, and a step of exposing the barrier film, and the remaining protective film. a step of forming a protruding electrode on the barrier film exposed by electrolytic plating using a mask as a mask, and a step of selectively removing the electrolytic plating wiring in order to release a short circuit between the protruding electrodes after forming the protruding electrode. A method of manufacturing a semiconductor device, comprising: