JPH03252143A - Semiconductor processing equipment - Google Patents

Abstract

PURPOSE:To enable uniform formation of bumps on a semiconductor substrate by providing a drip pan in the upper outer peripheral edge of an electrolyte bath used in forming metal bumps. CONSTITUTION:This equipment comprises a substrate holder 1 and an electrolyte bath: the former functions as the cathode with a semiconductor substrate 4 to form bumps 3 by electroplating; and the latter is supplied with electrolyte 6 from below to fill it by overflow of the upper peripheral edge, gets the substrate holder 1 with the semiconductor substrate below contact the liquid surface, and is furnished with an anode plate 7 in the bottom, and with a drip pan 8 in the upper outer peripheral edge. This structure allows flattening of the liquid surface of electrolyte which contacts the substrate and uniform contact of the substrate periphery with electrolyte as well as its center. It follows that bumps of uniform configuration are formed in the substrate periphery.

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] The present invention relates to the structure of an electrolyte bath used when forming a metal hump.

The purpose is to uniformly form bumps on a semiconductor substrate.

It has a substrate holder and an electrolytic solution tank, and the substrate holder functions as a cathode by setting a semiconductor substrate on which a hump is formed by electrolytic plating.

The electrolyte tank is filled with electrolyte by supplying the electrolyte from the lower part and overflowing from the upper periphery, and the substrate holder holding the semiconductor substrate on the lower side is brought into contact with the electrolyte surface and the tank is filled with electrolyte. An anode plate is provided at the bottom.

In addition, a receiving tray is provided on the upper outer periphery of the tank.

[Industrial application field]

The present invention relates to the structure of an electrolyte bath used when forming metal bumps.

Wire bonding has conventionally been widely used as a wiring method for semiconductor devices.

However, as semiconductor devices become more highly integrated, it becomes necessary to reduce the bonding space.

This method is becoming incapable of handling high-density connections.

[Conventional technology]

FIG. 3 is an explanatory diagram of a conventional example.

In the figure, 1 is a substrate holder, and 2 is an electrolyte tank.

3 is a hump, 4 is a semiconductor substrate, 6 is an electrolytic solution, 7 is an anode plate, and 9 is a resist.

Recently, it has replaced traditional wire bonding.

A bump method is a method that has become widely used.

This forms tiny metal bumps on the IC chip,
This is a method in which the hump and the bump or electrode of the opposing substrate to be connected are bonded to each other by pressure bonding.

According to this method, the wire connection interval is determined by the pitch of the bumps to be formed, and higher density wire connection is possible than with the wire bonding method.

FIG. 3 shows a conventional method of forming bumps on an IC substrate.

As shown in FIG. 3(b), a semiconductor substrate 4 is patterned with a resist 9 in advance to form bump formation regions with high density.
use.

This semiconductor substrate 4 is set in a substrate holder that serves as a cathode, and the surface of the semiconductor substrate 4 to be plated is directed toward the overflow surface of the electrolytic solution 6 of the electrolytic solution tank 2, so that the substrate 4 and the electrolytic solution 6 are brought into contact with each other.

Then, by applying a voltage to the cathode electrode connected to the semiconductor substrate 4 while overflowing the electrolytic solution 6 containing lead and tin (Pb-5n).

In the area not covered with the resist 9 on the semiconductor substrate 4,
Lead/tin solder is formed into a bump shape.

[Problem to be solved by the invention]

In order to form a large number of uniformly shaped bumps on the entire surface of the substrate, it is necessary that the entire surface of the substrate comes into uniform contact with the electrolytic solution and that the electrolytic solution is constantly replaced with new electrolytic solution.

On the other hand, in the conventional method, the electrolyte suddenly falls out of the tank at the upper end of the tank, making it difficult to achieve uniform contact between the substrate and the electrolyte around the substrate. As a result, the shape of the hump formed at the periphery of the substrate was significantly impaired.

For example, regarding the height of the hump, there is a difference of about 5% between the peripheral part and the central part of the board.

The present invention is provided for the purpose of uniformly forming bumps on a substrate.

[Means to solve the problem]

FIG. 1 is a diagram explaining the principle of the present invention.

In the figure, 1 is a substrate holder, 2 is an electrolyte tank 3 is a pan, 4 is a semiconductor substrate, 6 is an electrolyte, 7 is an anode plate, 8
is a saucer.

In order to correct the non-uniformity of the height of the bumps as described above, the upper periphery of the conventional electrolyte tank 2 shown in FIG.
It is preferable to provide a tray 8 as shown in FIG. 1(b).

Specifically, as in the present invention, the substrate holder 1 has a substrate holder 1 and an electrolyte tank 2, and the substrate holder 1 functions as a cathode by setting a semiconductor substrate 4 on which bumps 3 are formed by electrolytic plating. It is a thing.

The electrolytic solution tank 2 is supplied with an electrolytic solution 6 from the lower part and overflows from the upper periphery to be filled with the electrolytic solution 6, and the semiconductor substrate 4 is filled with the electrolytic solution 6.
The substrate holder 1 holding the substrate on the lower side is brought into contact with the electrolyte surface, an anode plate 7 is provided at the bottom of the tank 2, and
The conventional problem is solved by providing the receiving tray 8 on the upper outer periphery of the holder.

[Effect]

By providing such a saucer at the upper end of the outside of the electrolyte tank, the relationship between the flow of the electrolyte and the substrate at the top of the electrolyte tank is improved as shown in Figure 1, and at the top of the electrolyte tank, The plated metal surface of the semiconductor substrate 4 constantly comes into contact with the new electrolyte 6 jetting from below.

That is, in the conventional method, the electrolyte suddenly falls from the upper end of the tank toward the outside of the tank, but in the method of the present invention, the electrolyte in the tray acts as a buffer, and the electrolyte drops to the outside of the tray. Although it falls suddenly, it is possible to prevent it from falling outside the tank.

As a result, the surface of the electrolyte at the top of the tank can be flattened to the periphery of the substrate, and the contact between the periphery of the substrate and the electrolyte is stable, and uniformly shaped bumps can be formed on the periphery of the substrate. Formation becomes possible.

Of course, it is expected that a similar effect can be obtained by making the tank larger than the substrate.

In that case, the amount of electrolyte used increases several times, making it impractical.

〔Example〕

FIG. 2 is an explanatory diagram of one embodiment of the present invention.

In the figure, 2 is an electrolytic solution tank, and 4 is a semiconductor substrate.

8 is a saucer.

FIG. 2(a) is a perspective view of the electrolyte tank of the present invention.

As shown in the schematic cross-sectional view in FIG. 2(b), if the height hl of the receiving tray 8 is higher than the height to the substrate surface,
This is undesirable because the electrolyte gets to the back side of the substrate and the back side is also plated.

Furthermore, in FIG. 2, when h<h, the effect of flattening the liquid level becomes small.

Therefore.

h, ;hl　<h2 It is necessary to design the saucer so that

Using this electrolyte bath, solder bumps were formed on the semiconductor substrate 4. As shown in FIG. 1(b), the semiconductor substrate 4 is mounted with the surface to be plated facing down in a substrate holder 1 equipped with three claws, and a book having an outer diameter of approximately the same inner diameter and a receiving tray 8 provided on the upper edge of the periphery is attached. Place it over the electrolyte tank 2 of the invention.

The substrate holder 1 serves as a cathode and connects the terminal to a power source.

An anode plate 7 having a small hole with a diameter slightly smaller than the inner diameter of the tank 2 is placed near the bottom of the electrolyte tank 2.

The anode plate 7 is a Ti plate plated with PT.

The electrolytic solution 6 is sent in a jet form from the lower part of the electrolytic solution tank 2, and is ejected onto the plating surface of the semiconductor substrate 4 through the small holes of the anode plate 7.

Then, the electrolytic solution 6 is applied to the semiconductor substrate 4 at the periphery of the electrolytic solution tank 2.
It overflows from the gap between the electrolyte tank 2, enters the tray 8, overflows from the tray 8, and flows down to the outside of the electrolyte tank 2.

As shown in FIG. 1(b), the substrate holder 1 attached to the periphery of the semiconductor substrate 4 is used as a cathode.

A DC voltage of 1 cm is applied between the anode plate 7 and one of the semiconductor substrates 4 at 10 mA/cm! Flow the current.

A lead/tin solder bump electrode with a thickness of approximately 40 μm is formed.

(2) Therefore, the periphery of the substrate also comes into uniform contact with the electrolyte like the center.

(2) As a result, uniformly shaped bumps are formed also on the periphery of the substrate.

[Brief explanation of drawings]

FIG. 1 is a diagram explaining the principle of the present invention. FIG. 2 is an explanatory diagram of one embodiment of the present invention. FIG. 3 is an explanatory diagram of a conventional example. In fig. 1 is a substrate holder, 2 3 is a bump, 4 6 is an electrolyte, 7 8 is a saucer, and 9 is an electrolyte tank. is a semiconductor substrate. is the anode plate. [Effects of the Invention] According to the present invention, the following effects can be obtained by providing a receiving tray outside the conventional electrolytic solution tank. ■The surface of the electrolyte in contact with the substrate is flattened. Seri explanatory diagram Diagram (α) (shi) Explanatory diagram of Kibatsu Tomo's striking example Explanatory diagram of conventional example Part 3

Claims (1)

[Claims] It has a substrate holder (1) and an electrolyte tank (2), and the substrate holder (1) has a semiconductor substrate (4) on which bumps (3) are formed by electroplating. The electrolytic solution tank (2) supplies an electrolytic solution (6) from the bottom, and functions as a cathode.
The substrate holder (1) is filled with electrolytic solution (6) by overflowing from the upper periphery, and holds the semiconductor substrate (4) on the lower side.
) is in contact with the electrolyte surface, an anode plate (7) is provided at the bottom of the tank (2), and a saucer (8) is provided at the upper outer periphery of the tank (2). Semiconductor manufacturing equipment.