JPS61141157A - Manufacture of semiconductor element - Google Patents

Abstract

PURPOSE:To prevent the shapes of bump electrode and basic metal thereof from becoming defective, by a method wherein after forming a bump electrode coming into contact with an opening of a basic metallic layer, any parts of resist layer excluding the part directly below the bump electrode are removed and then any parts of basic metal layer excluding the part directly below the bump electrode are removed. CONSTITUTION:With a bond metallic film 7 on the surface of silicon wafer 1 a bump electrode 11 is formed in contact with a basic metal layer at an opening 10 by an electrolytic plating process utilizing a photoresist layer 9 on the basic metallic layer comprising a barrier metallic film 8 as a mask. Later the photoresist layer 9 is O2 plasma-etched to be left directly below the bump electrode 11 taking the role of a mask. Therefore, in case of a metallic bump, for example the basic metal, i.e. the barrier metallic film 8 and the bond metallic film 7, may be etched as they are without being coated with photoresists while the basic metal layer directly below the bump may be protected by the resist layer 9. Through these procedures, the normal shape of basic metallic layer may be maintained.

Description

[Detailed description of the invention] [Technical field to which the invention pertains]

The present invention relates to a method for manufacturing a semiconductor element having protruding bump electrodes that can be directly connected to external substrate terminals or lead & I terminals on a semiconductor wafer.

[Prior art and its problems]

Conventionally, bump electrodes of semiconductor devices have been formed using a process such as that shown in FIG. After forming an opening above the diffusion region 2 and depositing a wiring film 4 in contact with the region, a silicon nitride film 5 for surface protection is deposited, and an opening 6 is opened in the bump formation region ( Figure a) Adhesive metal film like 0 and 1?
, a barrier metal film 8 such as Go is formed by electron beam evaporation or the like, a photoresist layer 9 is provided to form an opening 10 by photoetching (Figure b), and then ^U or 5% is deposited by electrolytic plating. Next, the newly applied photoresist layer 12 is processed to cover the surface and periphery of the bump 11 (Fig. d). Barrier metal film 8.12 is used as a mask. The adhesive metal film 7 is continuously etched, and finally the photoresist 12 is removed using a resist remover (Fig. d). However, in this bump electrode formation method, the bumps 11 with a height of 20#II to 50μ are removed. It is difficult to uniformly apply the photoresist 12 that covers the surface and surrounding areas, and photoresist patterning defects 13 tend to occur near the bumps 11 (Figure d).
, followed by barrier metal film 8. When etching the adhesive metal film 7, acid or water that entered from the defective portion 13 remains and the bump becomes thinner14. Problems such as a defective bump shape 15 occurred (Fig. e), and there was a risk that the adhesion strength of the bump electrode 11 would decrease, affecting reliability.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and provide a method for manufacturing a semiconductor device that does not cause defective shapes of bump electrodes and their underlying metals.

[Key points of the invention]

According to the present invention, after the bump electrode is formed by plating in contact with the opening of the resist layer covering the underlying metal layer, the resist layer other than directly under the bump electrode is removed by plasma etching using the bump electrode as a mask, and then the bump electrode is etched. The above object can be achieved by etching away the base metal layer other than those directly below.

[Embodiments of the invention]

1 to 1e show the steps of an embodiment of the present invention, and parts common to those in FIG. 2 are given the same reference numerals. Figure 1 1
The steps shown in ~e are the same as the steps of the conventional method explained with reference to FIG.
Bump electrodes 11 are formed in contact with the base metal layer at openings 10 by electrolytic plating using the photoresist layer 9 on the base metal layer consisting of the barrier metal film 8 as a mask. Thereafter, the photoresist 9 is etched by 01 plasma etching according to the present invention, and at this time the bumps 11 serve as a mask, leaving the resist layer 9 directly under the bumps as shown in FIG. 1d. Therefore, for example, when forming a gold bump, it is possible to perform etching of the underlying metal, that is, the barrier metal l! 9, the underlying metal layer is maintained in its normal shape as shown in FIG. However, since it can withstand the temperature of 450°C for 1 second when bonding with a tin-coated copper lead wire terminal, the resist can be left unremoved. After forming a bump electrode by plating, plasma etching can be performed using the bump electrode as a mask, leaving the part directly under the bump electrode and removing the rest of the resist. The shape of the base metal layer directly under the bump is not damaged by water intrusion, and the adhesion strength of the bump to the wiring metal is maintained.Also, there is no need for resist patterning around the bump for etching the base metal layer. Since the use of a resist remover is replaced by plasma etching, the effect of the resist remover on the underlying metal layer is also eliminated, and the effects of streamlining the manufacturing process of semiconductor devices and improving reliability are extremely large.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a main part sequentially showing the process of forming a bump electrode in an embodiment of the present invention, and FIG. 2 is a cross-sectional view of a main part sequentially showing the process of forming a conventional bump electrode. 1: Silicon wafer, 2: Impurity diffusion region, 4: A!
Wiring, 7: Adhesive metal film, 8: Barrier metal film, 9: Photoresist layer, IO: Opening, 11: Bump electrode. Figure 1 Figure 2

Claims (1)

[Claims] 1) A method for manufacturing a semiconductor element having bump electrodes formed on a semiconductor wafer through a base metal layer, in which the bump electrodes are formed by plating in contact with openings in a resist layer covering the base metal layer, and then the bumps are formed on a semiconductor wafer through a base metal layer. 1. A method for manufacturing a semiconductor device, which comprises removing the photoresist layer except directly under the bump electrode by plasma etching using the electrode as a mask, and then removing the underlying metal layer except directly under the bump electrode by etching.