JPH0290529A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To form a solder bump on an Al electrode with high precision at low cost by a method wherein a dry film is laminated on a wafer to make a through hole in specified shape and then the hole is filled with solder paste impressed with ultrasonic to be fused later. CONSTITUTION:An ordinary commercial dry film 1 is laminated on a wafer chip 3 to make a through hole in an electrode part by exposure and development. Next, the through hole is filled with kneaded paste comprising commercial solder mixed with Sn-Pb composed solder containing a bit of Ti, Cd, Sb, etc. Then, heating seals 6 are pressed against the wafer downward and upward and then the wafer is impressed with ultrasonic to be connected. The solder paste fuses to destroy an Al2O3 oxide film on an Al electrode by cavitation effect of the ultrasonic and then the solder paste is connected partially by metallic junction and partially by coupling effect to form a solder bump. After removing tools, the dry film 1 is removed by ordinary process to form the complete solder bump.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for forming input/output electrodes of a semiconductor integrated circuit, and particularly relates to a method for forming input/output electrodes of a semiconductor integrated circuit. This invention relates to a solder panda forming method suitable for 71J round chip connection.

[Conventional technology]

The conventional device was manufactured by Micro Devices, 1987.

As described in the June issue, page 63, there was a method of applying ultrasonic waves to a molten solder bath, immersing a semiconductor chip, and forming solder bumps.

However, the problem with this method is that the height of the solder bumps that are generally formed is as low as about 10 μm to several tens of μm, and that the variation is large.

In other words, in the conventional method, the molten solder itself also serves as the heating source, and the amount supplied is almost infinite compared to the size of the pad, so slight changes in conditions when pulling the pad out of the solder bath can cause large changes in the amount of solder. It was inevitable.

On the other hand, conventional methods for forming bumps of this type have involved depositing solder entirely on a mask at a predetermined electrode position g, or applying wet plating.

The major disadvantage of these methods is that supplying thick solder with vapor deposition can be extremely costly, while with plating, although the cost is slightly lower, the accuracy of supplying the amount of solder decreases due to the need for etching accuracy. In some cases, there were problems with corrosion due to residual plating and etching solutions.

Furthermore, these methods require separate formation of adhesive metallization on the AP and electrodes, which inevitably increases costs.

[Problem to be solved by the invention]

All of the conventional techniques have the problem that sufficient consideration has not been given to the accuracy of the amount of solder supplied and the cost of forming bumps, making it difficult to adopt them as a bump forming method as a general-purpose technique.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems using a simple method and to form solder bumps with high precision at low cost.

[Means to solve the problem]

In terms of cost, the above problem can be solved by using expensive Au pandas as solder bumps, eliminating metallization for adhesion and directly soldering to the M electrode, and using dry film to control the solder supply. By supplying solder paste to the electrode parts from a regular company, it is possible to form solder bumps at any desired height and with high precision.

[Effect]

The dry film is laminated in wafer form.

Therefore, since individual chips are not processed, increasing the number of man-hours does not have much effect on cost. Further, the through holes in the electrode portion formed by etching have good etching accuracy, and if solder paste is supplied to these holes, paste can be supplied with high precision.

Furthermore, by heating while applying ultrasonic waves, the solder becomes M
The oxide layer on the electrode film is destroyed by the cavitation effect and connected to M while ensuring metallurgical bonding. At this time, by adjusting the paste material and the ultrasonic application conditions, there is no problem such as adhesion of solder to other components.

As described above, it is possible to form a chip with high precision at low cost on the M electrode, and the chip can be used for TAB or flip chip.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. 1. First, (α) a commercially available ordinary dry film 1 (thickness:
[mu]m) It was laminated on T wafer step 3, and this was also created by exposing and developing a 120 [mu]m square through hole in the electrode part (b) using a method well known to those skilled in the art.

Next, (c) solder with a composition of 63% Sn-s 7% Pb and a commercially available solder containing Ti r Cd r sb etc. were mixed with solder powder of 10 μm or less in diameter and an organic binder containing rosin to form a fM 95+. #t% solder composition,
A paste of viscosity 150K Cl) S is
The above through hole was filled with a rubber leg squeegee for screen printing.

Furthermore, (d) heating tool 6 at approximately 270°C from above and below the wafer.
, and applied ultrasonic waves of about 20KH7 to connect. The paste solder is melted, and the Al2O5 oxide film on the M electrode is destroyed by the cavitation effect of ultrasonic waves, and a solder bump is formed by partially metal bonding and partially connecting by the cobbling effect.

After removing the tool, (e) the dry film was removed by a conventional method to obtain solder bumps with a height of 55 μm. Due to the heat resistance of the dry film, peeling may occur when the tool is pressed, but there was no effect on bump formation according to the present invention because the solder wetted the M electrode.

After this, the S1 wafer goes through the normal dicing process and is then TA
It becomes possible to implement B or flip-step.

〔Effect of the invention〕

According to the invention, A1′r! There is no need to form adhesive metallization on the L electrode (also, processes such as vapor deposition and plating are not required), and expensive Au bumps can be replaced with solder pandas, so compared to ordinary wire bond chips, All LSI chips with high added value can be manufactured with a slight increase in cost.

[Brief explanation of drawings]

FIG. 1 schematically shows a process according to an embodiment of the present invention.
It is a process diagram shown as a partially enlarged view of a cross section. 1... Dry film, 2... A1' quadrupolar film,
3... S1 wafer (chip), 4... Solder paste, 5... Solder panda, 6... Heating/ultrasonic application tool. Proxy valve, (± Masaru Ogawa F-"謬l-・Dry life book Ru?...-A7 electric screw ll So3-・-8i wafer (+-, Bun 4・-r7fi-r-: East 5-・・l;n6′ha・〉a

Claims (1)

[Claims] 1. Laminate a dry film on a wafer that has gone through the normal chip process, make holes in a predetermined shape at predetermined bump positions, fill the holes with solder paste, and melt the solder while applying ultrasonic waves. A method for manufacturing a semiconductor device, comprising forming solder bumps directly on an Al electrode.