JPH04196323A - Structure of bump electrode part and formation thereof - Google Patents

Abstract

PURPOSE:To contrive improvement in reliability against corrosive ions and the like by a method wherein carbon black is formed by adsorption as the common electrode for plating to be used for application of a current on the electrode formed on the main surface of a semiconductor element. CONSTITUTION:An SiO2 film 12 is formed on a substrate 11, an electrode 13 to be used for lead out of an outer electrode and consisting of an Al film, for example, is formed thereon, and an SiO2 film 14, which is formed by opening a part of the main surface of the electrode 13, is worked into the shape as indicated in the diagram. Then, a metal film 15 is formed on the electrode 13 which is formed by opening the SiO2 film 14 of the electrode 13. A first photosensitive resist 20 is formed on the region excluding a part of the metal film 15 and the SiO2 film 14, and a film is formed on the whole main surface of the semiconductor substrate 11 by adsorption-treating a carbon black 21. Then, a second resist 22, which is formed by opening the prescribed area where a bump will be formed, a current is applied to the carbon black 21 and a bump electrode 23 is formed. As a result, the metal film on the electrode 23 is covered by carbon black, thereby enabling the metal film to prevent corrosion by corrosive ions and the like, and reliability can be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to TAB, which is one of semiconductor device mounting techniques.
(Tape Automated Bonding)
The present invention relates to the structure of a bump electrode part used in technology and a method of forming the same.

(Prior Art) This type of conventional technology is disclosed in Japanese Patent Publication No. 61-7742, an example of which is shown in FIG. 2 as a cross-sectional view of the process. A 5102 film 12 is formed on a semiconductor substrate 11, and a 5102 film 12 is formed on it by a resistance heating method, an electron beam method, etc.
．． An aluminum film with a thickness of 5 to 15 μm is formed, and the circuit elements formed on the semiconductor substrate 1 are connected by a half-etching method to form electrodes 13 for taking out external electrodes. Further, a VD 5102 film J4 formed at a low temperature is deposited on the entire surface, and only the vicinity of the electrode 13 is opened by photoetching.
(a) Figure).

Next, a metal film 15 consisting of a plurality of layers is formed over the entire surface by a vapor deposition method (see figure (b)). This metal film 15 is made of Cr-Cu
.

Ni-Cu, Cr-Ni-Cu or Cr-C
Multiple layers of u-Au, Ni-Cu-Au, Cr-Ni-Cu, etc. are deposited in sequence without breaking the vacuum during the same deposition.

Further, T] may be used instead of Cr or NiO. Cr
, Ni.

Ti is aluminum electrode 13 and CVD SiO2
This is a film to increase the adhesion of M14, and is made of Cu or C.
u-Au is a film for facilitating the formation of bumps by plating, and each of Cr, Nj, and Ti has a thickness of about 1000X, and Cu has a thickness of 1000 to 6000X.

Next, after applying a photosensitive resin 16 as a plating mask, only the vicinity of the electrode 13 to be plated is opened (Figure C), and the metal film 15 is used as a common electrode for plating.
* Metal bumps 17 such as cut solder are formed to a height of 5 to 20 μm (Figure (d)).

When the above steps are completed, the unnecessary photosensitive resin 16 and metal film 15 are removed in a dry atmosphere by plasma etching or ion etching to obtain the structure shown in FIG. Even if the photosensitive resin 16' remains here, there is no problem in reliability.

(Problem to be Solved by the Invention) However, in the method described above, the metal film 15 is used as a common electrode for bump plating and as an electrode for forming metal bumps 17 such as Au, Cu, solder, etc. Afterwards, the cross section of these metal films 5 is exposed on the side surface of the electrode 13 of the bump electrode, so if the exposed metal film is corroded by corrosive ions from the outside and the bump electrode peels off, then... There was a problem in that adhesive strength was likely to deteriorate.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention uses a black hole process to form a bump electrode.
In the process of forming pandas on the electrode.

A carbon blank layer is formed so that the metal film is not exposed to the outside of the bump electrode, and the metal film is energized as a common electrode using the black hole process.A thin film of carbine black is formed in contact with the metal film as a common electrode to form the bump electrode. It was designed to do so.

(Function) As described above, the present invention uses carbon black to prevent the metal film on the electrode of the Gunzo electrode from being exposed to the outside, so it will not be corroded by corrosive ions and the adhesive strength will deteriorate. It is possible to form highly reliable bump electrodes at temperatures as low as 30°F.

(Example) FIG. 1 is a process cross-sectional schematic diagram explaining the details of the present invention. Parts that are the same as those in the conventional example will be given the same numbers and will not be described further.

First, as shown in the figure (a), the 8102 film 12 is formed on the substrate 11 using the same technique as before, and on top of that is an electrode (J:) for taking out an external electrode made of, for example, A/film (hereinafter simply referred to as an electrode).
73 is formed, and a part of the main surface of the electrode 13 is opened.
The IO2 film 14 is processed into the shape shown.

Next, as shown in figure (b), the same technique as before is used.

A metal film 15 is formed on the electrode 13 in which the SIO2 film 4 of the electrode 13 is opened.

For this CVD SiO2 film 14, in addition to these, for example, a silicon nitride film (Sl, N4), a phosphorus glass film (PSG), etc. may be used, and in particular,
02 film 1ζ is not limited.

Next, as shown in FIG. 3(c), a photosensitive first resist 2θ is formed by photolithography technique except for a part of the metal film 15 and the 5102 film 14, and is further applied to the entire main surface of the semiconductor substrate 11. Adsorption treatment of carbon black 2 is carried out. This process is performed using, for example, black hole process technology.

The particle size of carpin black at this time was 150 to 2
000 nm, and a film of equivalent thickness is formed. Thereafter, as shown in FIG. 3(d), a second resist 22 with openings in predetermined areas where bumps will be formed is formed, and the carbon blank layer 21 is energized to form bump electrodes 23. After the formation of the bump electrodes 23 is completed, the first resist 20 and the second resist 22 are dissolved and removed using an organic solvent such as acetone, as shown in FIG. At the same time, the carbon black 21 other than the portion where the bump electrode 23 is formed is removed as the resist is dissolved. Since carbon black has countless fine pores that originally exist on the surface of the film, it is easy for chemical solutions to pass through it, so it can be easily removed using an organic solvent.

Next, as shown in FIG. ff1, the bump electrode 23 shown in FIG.

By heating and melting, the metal of the bump electrode, such as copper, gold, etc., forms an alloyed layer with the metal of the metal film, such as Cu, through the fine pores of the carbon black 21, and the metal film and the bump electrode are bonded together. The resistance of the carbon black layer existing in between is significantly lowered to the extent that no defects are found in terms of circuit functionality. Through the above steps, the structure shown in Figure (f) is obtained.

(C') Figure is an example of a method in which a layer of carbon black 2 is not present between the bump electrode and the metal film,
Although the state (3) is that the metal film 15 is slightly in contact with the metal film 15, the effect is the same.

(Effects of the Invention) As described above, according to the present invention, carbon black is adsorbed and formed as a common electrode for plating that conducts current to the electrode formed on the main surface of a semiconductor element, so that it can be used after bump formation plating. The process is to remove the resist masked in a predetermined area with an organic solvent, and at the same time, the carbon black in that area is also removed, and the metal film formed on the bump electrode can be formed without being exposed to the outside. , reliability against corrosive ions, etc. is improved, and the process of using chemicals such as acids and alkalis is reduced, so economical effects can be expected.

[Brief explanation of the drawing]

FIG. 1 is a process sectional view of an embodiment of the present invention, and FIG. 2 is a process sectional view of a conventional example. 1no...Semiconductor substrate, 12.14...S IO2 film, 13°°. Electrode, 15... Metal film% 20... First resist,
21...Woukan pike, 22...Second resist, 23...Bump electrode. Fig. 1 (1s1) Practical test 110) process 1 of the present invention Fig. 1 (No. 02)

Claims (2)

[Claims] (1) As a structure of a bump electrode part in a semiconductor device, a bump electrode part characterized in that a carbon black layer is formed between the bump electrode and an external electrode extraction electrode formed on a semiconductor substrate. structure. (2) In forming the bump electrode portion of the semiconductor device, (a) forming an electrode for taking out an external electrode on the semiconductor substrate;
(b) forming a metal film on the main surface of the electrode; (c) forming a first metal film on the main surface of the electrode except for substantially the top; (d) forming a second resist except for the portion where the bump electrode is to be formed to form the bump electrode; (e) after that. . A method for forming a bump electrode portion, comprising the steps of: removing the first and second resists, and removing the carbon black other than the portion of the bump electrode.