JP3175875B2 - Jet plating equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a facility for manufacturing semiconductor devices or integrated circuit devices, and more particularly to a jet plating apparatus for performing bump plating or wiring plating on a silicon wafer surface.

[0002]

2. Description of the Related Art Conventionally, a jet plating apparatus capable of high-speed plating has been used to apply bump plating or wiring plating to a semiconductor wafer. FIG. 5 is a vertical sectional view of a conventional jet plating apparatus and a plating solution circulation system diagram.

In the jet plating apparatus, a cylindrical jet cup 2 is placed in a plating bath, a wafer 1 to be plated is placed on the upper end of the jet cup 2, and a plating solution 12 is applied from below the jet cup to the surface of the wafer 1. To form a plating layer. The plating is required to be plated to a uniform plating thickness over the surface of the semiconductor wafer.

However, during plating, bubbles are generated from the electrode portion. If air is present in the plating solution 12 or the pump 9, the plating solution containing air is ejected, and when the plating solution flow becomes turbulent, the air in the plating solution aggregates to generate bubbles. If the bubbles stay on the surface of the semiconductor wafer 1, a plating film having a uniform thickness is not formed. Further, if the amount of the plating solution passing along the surface of the semiconductor wafer 1 varies, the thickness of the plating film formed on the surface of the semiconductor wafer 1 is not uniform. As a result, the manufacturing yield of semiconductor chips cut from the semiconductor wafer is reduced.

Various attempts have been made to prevent these problems. For example, there has been proposed a device in which an electrode in a tank is arranged in another tank communicating with the jet cup portion so that generated bubbles do not enter the jet cup portion (Japanese Utility Model Application Laid-Open No. 64-3084).
4). However, this device has a complicated structure, so that the manufacturing cost of the device is increased, and there is a problem that a great deal of labor is required for maintenance management.

On the other hand, various apparatuses have been proposed for the purpose of keeping the flow rate of the plating solution constant in the plane of the semiconductor wafer. For example, there is known an apparatus in which a porous flow straightening plate is arranged at the bottom of a jet cup so that the plating solution in the jet cup is straightened (Japanese Utility Model Laid-Open No. 3-34064). Further, the current plate may be used as an electrode.

In addition, by making the gap between the semiconductor wafer above the support pins provided at the upper end of the opening of the jet cup and the upper end of the opening of the jet cup constant, the amount of the plating solution can be adjusted in any direction of the semiconductor wafer. There is also known a device that flows at a constant flow rate.

Further, by mounting a ring member having a central portion opened on the inner peripheral surface of the upper end portion of the opening of the jet flow cup, the plating liquid is concentrated on the central portion of the lower surface of the semiconductor wafer, thereby increasing the plating flow rate and increasing the plating liquid flow. A device for preventing stagnation is also known (Japanese Utility Model Laid-Open No. 57-73927).

However, even with the above-mentioned apparatus, it was still impossible to prevent bubbles from stagnating on the surface of the semiconductor wafer, and a plating film having a uniform thickness could not be obtained.

[0010]

The problem is that air bubbles generated from the electrode portion during plating do not stay on the surface of the semiconductor wafer, and the amount of plating solution passing along the surface of the semiconductor wafer is made uniform. Accordingly, it is an object of the present invention to provide a jet plating apparatus having a uniform plating film thickness formed on the surface of a semiconductor wafer, having a simple structure, not increasing production costs, and being easy to maintain.

[0011]

In order to achieve the above object, the present invention relates to a jet plating apparatus for plating a surface of a plate to be plated, wherein the plate to be plated is suspended in a horizontal state with a plating solution. A press plate for regulating the upper limit position of the plate; a clamping jig for the press plate; an electrode rod in contact with the plate; a jet cup for jetting a plating solution onto the plate; Consisting of a plurality of electrodes arranged inside the cup and a plating solution tank containing a plating solution jetted onto the plate to be plated, having a plurality of weirs and a notch therebetween between the upper end surface of the jetting cup. It is a jet plating apparatus characterized by the following. The electrode rod is usually inserted into a hole formed in the holding plate and the fastening jig.

The plurality of cutouts are generally rectangular, but the thickness of the water film in the circumferential direction of the jet cup is reduced so that the water film breaks in the flow over the weir at the upper end of the jet cup. Any shape that has the effect of changing and falling, such as a triangle,
Various shapes such as an arc shape can be applied, and the shape is not limited to a rectangular shape.

It is preferable that the plurality of electrodes disposed on the bottom of the jet cup are arranged symmetrically with the axis of the jet cup and parallel to the axis.

[0014]

The jet cup of the present invention is provided with a rectangular notch 5b so as to form a plurality of weirs 5a on the upper end face as shown in FIG. 3, for example. Therefore, the flow exceeding the upper end of the jet cup falls in a curtain shape having a thickness changed according to the notch 5b, and falls, and a curtain-shaped water film passes over the weir 5a at the upper end of the jet cup and the curtain shape passes over the notch 5b. Since the shape of the film is different from that of the water film, a discontinuous portion is generated at the boundary between the two curtain-shaped water films. Therefore, as shown in FIG. 1, the gap 18 generated between the inner free surface 17 of the flow over the upper end of the jet cup and the side wall of the jet cup is not insulated from the atmospheric pressure space 19 and no negative pressure is generated. The flow rate of the overflow is stable, and as a result, the flow rate along the semiconductor wafer surface is also stable.

Further, a plate 5 to be plated and a weir 5 above the jet cup.
When the notch 5b is provided, the way of changing the interval between the upper surfaces of the portions a becomes slow and stable because the outflow of the notch 5b functions as a stabilizing action.

Further, the problem that the speed of the plating solution parallel to the plate to be plated 1 becomes higher toward the outer peripheral portion was reduced, and the problem that the plating film thickness became thinner toward the outer peripheral portion was solved.

On the other hand, as a countermeasure against bubbles, the cutout 5b causes the flow of the water stream to bend at a lower portion, so that the generated bubbles are easily discharged before reaching the surface of the plate 1 to be plated. In addition, the turbulence of the liquid colliding with the central portion of the surface of the plate 1 is small, and bubbles are hardly trapped.

Since bubbles are generated on the surface of the electrode 6, if the electrode 6 is placed horizontally, the bubbles rise over a wide area and come into contact with the bubbles over a wide area of the plate 1 to be plated. In the case of the vertical installation, the bubbles rise along the surface of the electrode 6, so that there is a possibility that the upper portion of the electrode 6 on the plate to be plated contacts the bubbles. When the electrode 6 is placed relatively vertically on the outer peripheral portion of the jet cup 2, the bubbles are discharged along the discharge flow and do not reach the surface of the plate 1 to be plated.

Further, by disposing the electrode 6 in parallel with the axis of the jet cup 2, the plating solution rising in the jet cup 2 is rectified.

Further, since the electrodes 6 are arranged symmetrically with respect to the axis of the jet cup 2 and in parallel with the axis, the plate 1 to be plated is provided.
Is uniform, and a plating film having a uniform thickness is formed.

[0021]

FIG. 1 is a vertical sectional view of a jet plating apparatus and a diagram of a plating solution circulation system according to an embodiment of the present invention. An embodiment according to the present invention will be described with reference to FIG.

The plate 1 to be plated is a cylindrical jet cup 2
The holding plate 3 of the plate 1 to be plated is fixed by a fastening jig 4. Rubber holding plate 3a
The electrode rod 13 is inserted into a hole formed in the holding plate 3b and the clamping jig 4 made of vinyl chloride, and is in contact with the plate 1 to be plated.

A rectangular notch 5b having a width of 19 mm and a depth of 3 mm is provided at an upper end of the jet cup 2 at equal intervals over the entire circumference thereof.
Has eight. The portion without the notch becomes the weir 5a. The bottom surface of the lower end of the jet cup 2 is not open but closed, and a jet pipe 8 for jetting a plating solution, which is opened at the center of the bottom surface, is attached. The ejection pipe 8 communicates with the pump 9 via a flow controller 15 and a filter 16.

The jet cup 2 is accommodated in a tank 10, and the upper end of the tank 10 is located at a height sufficiently higher than the plate 1 to be plated. A plating solution discharge pipe 1 is provided on the bottom of the tank 10.
1 is open, and the discharge pipe 11 communicates with the pump 9.

An electrode 6 is arranged inside the jet cup 2. The electrode 6 has four flat plates arranged symmetrically to and parallel to the axis of the jet cup 2, and the upper end of the electrode 6 is located lower than the lower part of the upper cutout 5 of the jet cup 2.

The electrode 6 and the electrode rod 13 are connected to a power source (not shown) by wiring. In the case shown in the figure, the electrode 6 is a flat plate-shaped four electrode made of copper having a height of 40 mm, a width of 30 mm, and a thickness of 5 mm, and is vertically arranged inside the jet cup 2 in parallel with the central axis of the jet cup 2. Electrode 6 on bottom of cup 2
Were arranged so that one edge of the contact was made.

The shape of the electrode 6 is not limited to a flat plate, but may be a curved plate having a curvature in the circumferential direction of the jet cup 2. The electrode 6 may have a hole. The number of electrodes 6 to be arranged is arbitrary as long as it is two or more, and the interval between the electrodes 6 is also arbitrary. For example, a structure in which the perfect electrode 6 is in contact with the side wall of the jet cup 2 may be used.

When the electrode 6 is located near the side wall of the jet cup 2, bubbles rising along the electrode 6 can easily escape to the outside.

Next, the operation of the embodiment according to the present invention will be described.

The bath 10 is filled with the plating solution 12 so that the level of the plating solution 12 is lower than the lower surface of the plate 1 to be plated.

The plating solution 12 filled in the tank 10 is ejected from the ejection pipe 8 into the ejection cup 2 by the pump 9 via the discharge pipe 11.

The jetted plating solution 12 rises in the jet cup 2 to raise the plate 1 by about 10 mm, and the plating solution 12 is discharged from the gap between the plate 1 and the weir 5a and the notch 5b of the jet cup 2 to the outside of the jet cup 2. And is discharged into the tank 10 as a flow passing over the upper end of the jet cup 2.

On the other hand, when the electrode 6 and the electrode rod 13 were connected to a power supply (not shown) and copper plating was performed, a good plating film was obtained on the plate 1 to be plated. The plating conditions were as follows: plating solution composition: CuSO ₄ 15 per liter of water
0 g, 123 ml (milliliter) of H ₂ SO ₄ , current 2
The plating time was 40 mA and the plating time was 900 seconds. The electrode 6
Copper plating was performed in the same manner as in the above-described apparatus except that the number of sheets was changed to two. As a result, a good plating film was obtained although it was slightly inferior to the case of four sheets.

By arranging the electrode 6 vertically, the jet from the jet pipe 11 rises as a parallel flow without being disturbed. The bubbles generated at the electrode 6 rise from the upper end of the electrode 6. The bubbles are formed in the jet cup 2 above the jet cup 2.
It is discharged out of the jet flow cup 2 by the flow in the circumferential direction from the central axis. Since the flow in the circumferential direction bends from the lower side of the plate 1 due to the action of the notch 5b, the air bubbles were discharged out of the jet cup 2 before reaching the plate 1.

In the embodiment shown, only one jet cup 2 is arranged. However, it goes without saying that a plurality of jet cups 2 are arranged in the tank 10 and the plurality of plates 1 to be plated can be plated simultaneously.

For comparison, a plating operation was performed with the electrode 6 placed horizontally. In this case, the jet flow from the discharge pipe 11 is directly blocked by the electrode plate, a sufficiently rectified plating solution flow cannot be obtained, and many bubbles come into contact with the semiconductor wafer surface, so that a uniform plating film cannot be obtained. Was.

Further, for comparison, as shown in FIG. 4, in order to prevent the rising flow of the plating solution from becoming turbulent, the electrode 14 of a donut-shaped flat plate having many holes made of copper is jetted. When copper plating was performed on the table 7 placed on the bottom surface of the cup 2 horizontally, a sufficiently rectified plating solution flow was not obtained, and bubbles contacted the semiconductor wafer surface to form a uniform plating film. Was not obtained.

Further, when copper plating was carried out with the electrodes of a platinum net less disturbing the plating solution flow, the current flow was poor, and a uniform and thick plating film could not be obtained.

[0039]

Since the present invention is configured as described above, it has the following effects.

(1) Bubbles generated from the electrode portion during plating and bubbles generated by collecting air in the plating solution circulating pump do not stagnate on the surface of the plate to be plated, and are discharged along the discharge flow. Therefore, the amount of the plating solution passing along the plate to be plated does not become uneven, and a uniform plating film thickness is formed on the surface of the plate to be plated.

(2) The notch provided at the upper part of the jet cup stabilizes the flow rate of the plating solution over the upper end of the jet cup.
A uniform plating film thickness is formed on the surface of the plate to be plated.

(3) The structure is simple and the production cost is not high.
In addition, it is possible to provide a jet plating apparatus that can be easily maintained.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view of a jet plating apparatus according to an embodiment of the present invention and a diagram of a circulation system of a plating solution.

FIG. 2 is a cross-sectional view of the jet plating apparatus according to the embodiment of the present invention.

FIG. 3 is a perspective view and a cutaway explanatory view of the jet cup according to the embodiment of the present invention.

FIG. 4 is a longitudinal sectional view of a jet plating apparatus in which a donut-shaped flat plate electrode is provided on the bottom surface of a jet cup.

FIG. 5 is a longitudinal sectional view of a conventional jet plating apparatus and a circulation system diagram of a plating solution.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plate to be plated 2 Jet cup 3a, 3b Pressing plate 4 Tightening jig 5a Weir 5b Notch 6 Electrode 7 units 8 Jet pipe 9 Pump 10 Tank 11 Discharge pipe 12 Plating liquid 13 Electrode rod 14 Electrode 15 Flow controller 16 Filter 17 Inside Free surface 18 Void 19 Atmospheric pressure space

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-205696 (JP, A) JP-A-58-182823 (JP, A) JP-A-4-246199 (JP, A) JP-A-4- 315434 (JP, A) JP-A-57-89495 (JP, A) JP-A 2-99970 (JP, U) JP-A 64-41131 (JP, U) JP-A 63-94967 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) C25D 5/08 C25D 7/12 H01L 21/288

Claims (2)

(57) [Claims] 1. A jet plating apparatus for plating a surface of a plate to be plated, comprising: a holding plate for regulating an upper limit position of the plate to be plated when the plate to be plated is suspended in a plating solution in a horizontal state; A clamping jig for the holding plate, an electrode rod in contact with the plate to be plated, a jet cup for jetting a plating solution onto the plate to be plated, a plurality of electrodes arranged inside the jet cup, and a jet for the plate to be plated. is composed of a plating solution tank for accommodating the allowed was plating solution, possess a plurality of weirs and a notch therebetween on the upper end face of該噴flow cup, the electrodes該噴
A jet plating apparatus, which is disposed symmetrically with and parallel to the axis of the flow cup . 2. The jet plating apparatus according to claim 1, wherein the shape of the notch is rectangular.