JPH0350734A - Manufacture of integrated circuit - Google Patents

Abstract

PURPOSE:To increase adhesion strength of a bump type electrode by a method wherein in a process forming a photo resist film on a metal film in which an adhesion layer, a mutual diffusion barrier film, and a base electrode film are formed in order, the aperture is formed in the inside of a passivation aperture part. CONSTITUTION:A Ti film 13 as an adhesion layer, a Pt film 14 as a mutual diffusion barrier film, and an Au film 15 as a plating base layer are formed in order by sputtering method, on a passivation film 11 and an electrode pad 12 of an integrated circuit surface in which the processes of diffusion, wiring, and an insulating film are finished. A photo resist coating film 16 is spread on a metal film, its aperture part for forming a bump type electrode is formed in the inside of the passivation aperture part. An Au bump 18 is formed in a photo resist aperture part 17 by electroplating of Au. After the photo resist 16 is eliminated by using release liquid, the Ti film 13, the Pt film 14, and an Au film 15 are etched and eliminated by dry etching using the Au bump 18 as a mask. Thereby a bump type electrode which is excellent in adhesion strength and has high mounting stability can be easily manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing an integrated circuit, and more particularly to an integrated circuit having gold bumps for electrodes serving as external connection terminals.

[Prior Art J] Conventionally, many proposals have been made and improvements have been made regarding methods of manufacturing gold bumps for electrodes of integrated circuits. FIG. 2 is a sectional view showing the manufacturing process of a conventional gold bump for electrodes.

Conventionally, as shown in FIG. 2, the first metal film, second metal film, and third metal film are sequentially formed on the entire surface of an integrated circuit, and a photoresist film is applied thereon.

The opening of this photoresist film includes the entire passivation opening, and after forming a bump type electrode by electrolytic plating using the photoresist film as a mask, the photoresist film is peeled off. After removing the resist film, removing the third metal film by wet etching,
The second metal film is removed by dry etching using the bump type electrode as a mask material. Finally, the third metal film is removed by wet etching using the second metal film as a mask material.

The integrated circuit formed in this manner has the following drawbacks.

First, since the manufacturing method uses wet etching, side etching occurs due to excessive etching and battery reaction, resulting in poor adhesion of the bump type electrode.

In addition, in the process of applying photoresist and forming an opening, the opening of the photoresist film is formed to include the entire passivation opening, so the bump-type electrode formed using the photoresist film as a mask is made of aluminum. It is formed using a portion of the pad that includes part of the passivation as a base. If this structure is subjected to large thermal or mechanical damage when bonding with the external lead electrode, cracks may appear in the passivation, cracks may occur in the oxide film under the aluminum pad or the silicon substrate, and bumps may be removed from the substrate. There was a problem that the mold electrode would peel off.

[Problem to be Solved by the Invention 1] The present invention aims to solve the drawbacks of the prior art described above, and is an integrated method that can form bump-type electrodes with high adhesion strength and high mounting stability through a simple process. The purpose is to provide a method for manufacturing circuits.

[Means for Solving the Problems] In a method for forming bump-type electrodes on electrode pads of an integrated circuit, (a) a first metal film as an adhesion layer and a second metal film as an interdiffusion barrier film are formed on the entire surface of the integrated circuit; a first step of sequentially forming a metal film and a third metal film as a base electrode for electrolytic plating;

(b) a second step of forming a photoresist film on the metal film, the opening of which is formed inside a passivation opening;

(c) A third step of performing electrolytic plating using the photoresist film as a mask and the third metal film as an electrode so that the outer periphery of the mushroom-shaped bump-type electrode is formed to the outside of the passivation opening. (d) a fourth step of peeling and removing the photoresist film; (e) using the bump type electrode as an etching mask material, removing the first metal film, second base metal film, and third metal film; A method for manufacturing an integrated circuit, comprising a fifth step of dry etching removal in a self-aligned manner.

[Embodiment 1] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIGS. 1(a) to 1(e) are sectional views showing the steps of the present invention in detail for explaining the present invention.

As shown in FIG. 1(a), a layer of O, lum ~ 0 is applied as an adhesion layer on the passivation film 11 and electrode pad 12 on the surface of the integrated circuit after the diffusion, wiring, and insulating film processes have been completed.
．． A 2 um thick Ti film 13 and a 0.0 um thick Ti film 13 are used as a mutual diffusion barrier film.
A PT film 14 with a thickness of 1 μm to 0.2 μm and an Au film 15 with a thickness of 1 μm to 0.3 μm as a plating base layer are sequentially formed by sputtering.

Next, as shown in FIG. 1(b), a photoresist film 16 is applied on the metal substrate, and an opening for forming a bump type electrode is formed inside the passivation opening.

Next, as shown in FIG. 1(c), the photoresist opening 17 is plated with Au to a thickness of 15 to 30 μm.
Bumps 18 are formed.

Next, as shown in FIG. 1(d), the photoresist 16
is removed using a stripping solution.

Next, as shown in FIG. 1(e), ion meenong,
By dry etching such as sputter etching, the above A
Using the u bump 18 as a mask, the Ti film 13 and Pt1
Li14 and Au11!15 are removed by etching.

Through the above steps, gold bump electrodes are formed on the integrated circuit.

The gold bump electrode formed in this manner has high adhesion strength and has a structure in which thermal and mechanical stress during mounting is absorbed by the aluminum pad, so it has high mounting stability.

[Effects of the Invention] As described above, according to the present invention, a bump-type electrode having excellent adhesion strength and high mounting stability can be easily manufactured.

[Brief explanation of drawings]

FIGS. 1(a) to 1(e) are cross-sectional views shown in order of steps for explaining the present invention in detail. FIGS. 2(a) to 2(f) are cross-sectional views shown in the order of steps for explaining the prior art. 10 ・ 11 ・ l 2 ・ l 3 ・ 14 ・ l 5 ・ l 6 ・ 17 ・ 18 ・ 20 ・ 2 l ・ 22 ・ 23 ・ 24 ・ 25 ・ 26 ・ ・Integrated circuit board・Passivation film・Electrode pad・Ti1l@ - PT film, Au film, photoresist film, opening, Au bump, integrated circuit board, passivation film, electrode pad, Ti film, PT pus, Au film, photoresist film 27 ・ ・More than Au bump

Claims (1)

[Claims] A method for forming a bump-type electrode on an electrode pad of an integrated circuit, comprising: (a) a first metal film as an adhesive film, a second metal film as an interdiffusion barrier film, and a second metal film as an interdiffusion barrier film; a first step of sequentially forming a third metal film as a base electrode for electrolytic plating, and (b) a step of forming a photoresist film on the metal film, so that the opening is inside the passivation opening. (c) electroplating is performed using the photoresist film as a mask and the third metal film as an electrode, so that the outer periphery of the mushroom-shaped bump-shaped electrode is in the passivation opening. (d) a fourth step of peeling and removing the photoresist film; (e) using the bump-type electrode as an etching mask material to remove the first metal film; , a fifth step of removing the second metal film and the third metal film by dry etching in a self-aligned manner.