JPH0441697A - Contact pin for plating - Google Patents

Abstract

PURPOSE:To prevent plating liquid from being penetrated into an electric contact part and to prevent abnormal growth of plating by providing an insulating cover around a pin made of metal, deforming and closely sticking the insulating cover in a state wherein the pin is pushed on the material to be worked. CONSTITUTION:A contact pin 1 made of metal is electrically brought into contact with the material to be worked. This contact pin 1 is fitted to an insulating cover 2 which is soft and made of the chemical resistant material and has a suction cup. The tip face of the insulating cover 2 is slightly projected from the pin 1 in a free state. When the pin 1 is pushed on a semiconductor base plate, wherein an electroconductive thin film of a substrate is formed, the insulating cover 2 is deformed and the pin 1 is brought into contact with the semiconductor base plate. Simultaneously, the tip face of the insulating cover 2 is closely stuck to the semiconductor base plate and thereby plating liquid is prevented from being penetrated thereinto. Thereby, abnormal growth of plating deposit is not caused and the powdery spill of the plating deposit is prevented. Good plating is obtained, which is uniform in thickness and free from a projection.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to the structure of a plating contact pin for performing bump plating onto IC electrodes on a wafer.

[Summary of the Invention 1] The present invention provides a method for preventing electrical contact portions from being exposed to a plating solution during one-step plating on a workpiece that has poor conductivity and is easily damaged, such as a semiconductor substrate (wafer). This relates to the improvement of plating contact pins to prevent abnormal growth of plating deposits on electrical contact areas, and to prevent the pins that enable electrical connection from being exposed to the plating solution. It is characterized by being composed of an insulating cover for the purpose.

[Conventional technology] To electrolytically plate metal on a substrate with poor electrical conductivity such as a semiconductor substrate (wafer), first a thin metal film with good conductivity is deposited on the substrate by sputtering or the like to serve as a plating base. After that, the contact pins are pressed against the substrate and electrolytically plated.

FIG. 4 is a partial schematic sectional view of a conventional example in which a plating contact pin is used to electrically connect to a semiconductor substrate (Uni A).

In the figure, 9 is a claw-shaped plating contact pin that comes into contact with the surface of the semiconductor substrate (wafer) that is the workpiece, and is made of a metal with low electrical resistance such as copper. Nine pieces are attached and held in a five-cup plating tank.

In this state, the semiconductor substrate (
The cross-sectional view of FIG. 3 shows abnormal precipitation of plating precipitates at the contact area between the plating contact pin (wafer) and the plating contact pin.

In this figure, 9 is a contact pin for fitting, and the insulation coating 3 is made of resin such as epoxy except for the tip of the pin.
is insulated by coating the surface. Reference numeral 4 denotes a semiconductor substrate (Uni A) which is a workpiece.For example, this is subjected to electrolytic plating of Au.
The structure was such that after approximately 0 to 1000 conductive thin films were deposited, main plating was performed.

[Problems to be Solved by the Invention] In such a plating contact pin structure, since the area in contact with the base conductive film 12 is small, the voltage drop in this part is large, and plating deposits such as Au are generated in this part. Abnormal growth 10 occurs.

This abnormal growth 10 of plating precipitates is in powder form and easily falls off, and adheres to the surface of the semiconductor substrate (wafer) during plating, causing plating defects such as protrusions.

[Means for Solving the Problems 1] The present invention solves the above-mentioned problems, suppresses variations in plating, and performs plating with a high yield. This is to provide a structure for contact pins for plating that prevents abnormal growth of plating deposits and prevents these plating precipitates from turning into powder and spilling over and adhering to the plating surface. It has a structure that includes a metal pin and an insulating cover around the pin, and when the pin is pressed against the workpiece, it is flush with the workpiece and prevents the intrusion of plating solution.

The insulator cover is made of a soft material and has a suction cup shape, and when the pin is pressed against the workpiece, the insulator cover deforms and comes into close contact with the workpiece, so that the present invention can be easily carried out. You can.

[Function] This prevents the plating solution from entering the electrical contact area between the plating contact pin and the semiconductor substrate (wafer), eliminates abnormal growth of plating deposits that occur around the pin, and prevents abnormal growth from occurring. Prevents plating defects due to powder.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of a main part of a plating contact pin according to the present invention.

In the figure, 1 is a pin that is a highly conductive metal material that electrically contacts the workpiece to be plated. This pin 1 is made of a soft material such as silicone rubber and is attached to a suction cup-shaped insulating cover 2 made of a chemical-resistant material. When the insulator cover 2 is free and not plated, its tip protrudes slightly as shown in figure G, and when the pin l is pressed against a semiconductor substrate, etc. on which a conductive thin film is formed as a base for plating, it becomes flexible. The insulator cover 2 is deformed and the pins come into contact with the semiconductor substrate (wafer). At the same time, the tip of the insulator cover 2 comes into close contact with the semiconductor substrate (wafer), and the plating solution penetrates into this. prevent. This prevents the plating solution from entering the area where the pin l contacts the semiconductor substrate (wafer), and only the semiconductor substrate (wafer) outside the area where the insulator cover 2 contacts is plated. There is no abnormal growth of precipitates, and therefore there is no powdery spillage of plating precipitates, and a good plating with a fairly uniform thickness and no protrusions can be obtained.

Furthermore, even if the contact between the insulator cover 2 and the semiconductor substrate (wafer) is not perfect and a slight amount of plating liquid intrudes,
The amount of new solution required for plating is small, and even if an abnormality occurs with plating deposits, the spilled powder will accumulate on the bottom of the insulator cover and will not pass through the gap, preventing the semiconductor substrate ( This has almost no effect on the plating on the surface of the wafer.

The cross-sectional view in FIG. 2 shows that the plating contact pins according to the embodiment of the present invention are attached and held in a cup-shaped plating bath, and a semiconductor substrate (wafer) is set thereon and electrically connected. FIG. 2 is a diagram schematically showing a state in which plating can be performed.

In this state, bump plating with gold, solder, etc. was performed, and when the surface of the semiconductor substrate (wafer) was inspected, it was found that almost no plating material was deposited outside the bump formation area, unlike conventional plating. A high yield was achieved with no plating defects. It goes without saying that the surfaces of the pins except for the tips of the pins are coated with an insulating film 3 made of resin such as epoxy for insulation.

[Effects of the Invention] As described above, when the plating contact pin according to the present invention is used, there is an insulating cover around the electrical contact portion between the pin and the workpiece to be plated.

Since the plating solution does not penetrate into the electrical contact portion and abnormal growth of the plating can be prevented, good plating without protrusions etc. can be obtained.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of a plating contact pin in an embodiment of the present invention, and Fig. 2 shows a plating contact pin in an embodiment of the present invention attached to a cup-shaped plating bath, and a semiconductor substrate (wafer) set therein. , a partial cross-sectional view showing the electrical connection state, FIG. 3 is a cross-sectional view showing abnormal growth of plating deposits at the contact portion of the plating contact pin in the conventional example, and FIG. 4 shows the electrical connection state in the conventional example. FIG. 1... Pin 2... Insulator cover 3... Insulating coating film 4... Wafer (workpiece) 1 pin Figure 3F!!j This invention ■Chorus technique interpretation 1 [1 face view Figure 2 #M Buddha in the holder ■Curved view No. 4 flash

Claims (2)

[Claims] (1) A metal pin 1 for electrically contacting the workpiece to be plated, and an insulating cover 2 around this pin 1.
with the pin 1 pressed against the workpiece.
A contact pin for plating, characterized in that the tip surfaces of the insulator cover 2 and the insulator cover 2 are flush with each other, and have a structure that prevents the intrusion of plating solution. (2) The insulator cover 2 is made of a soft material and has a suction cup shape, and has a structure in which the insulator cover 2 deforms when the pin 1 is pressed against the workpiece and is flush with the pin 1. A plating contact pin according to claim 1, characterized in that: