JPH0637355U - Wafer plating machine - Google Patents

Abstract

(57) [Summary] [Purpose] To completely remove the bubbles in the plating solution that are in contact with the lower surface of the wafer. A plating solution outlet 21 is provided in a predetermined area on the upper surface of the cup 2, and a plating solution jet port 5 is provided at the bottom of the cup 2 on the side facing the plating solution outlet 21. There is. Then, the plating solution 4 jetted into the cup 2 from the plating solution jet port 5 runs along the lower surface of the wafer 12 from the side corresponding to the plating solution jet port 5 to the plating solution outlet port 2.
It flows in one direction toward the side corresponding to 1, and overflows from one plating solution outlet 21. In this case, since there is only one plating solution outlet 21, the flow of the plating solution 4 passing through the plating solution outlet 21 is relatively fast, and the plating solution 4 is provided along the surface to be plated of the wafer 12 in a predetermined manner. Since the air flows in one direction and then overflows, the bubbles in the plating solution 4 contacting the lower surface of the wafer 12 can be smoothly removed without stopping anywhere.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 This invention relates to a wafer plating apparatus for plating a semiconductor wafer.

[0002]

[Prior art]

 For example, when forming bump electrodes on a semiconductor wafer (hereinafter simply referred to as a wafer), a plating resist layer is formed on the bump electrode formation surface (surface to be plated) of the wafer, and the plating resist layer is etched to form openings. By forming the pad portion, the pad portion is exposed through this opening, and the exposed pad portion is plated with gold or the like by using a wafer plating apparatus, and the bump electrode is formed by this plating.

By the way, in the conventional wafer plating apparatus, a gap is provided almost entirely between the upper surface of the cup on which the plating solution is jetted and the periphery of the surface to be plated of the wafer arranged above the cup. The plating solution is collected by overflowing the plating solution. However, since the cathode electrode connected to the plating connection terminals provided at a plurality of predetermined locations around the surface to be plated of the wafer is provided on the upper surface of the cup, the cathode electrode does not come into contact with the overflowing plating solution. In order to prevent the plating, and thus the expensive gold (plating metal) in the plating solution from being consumed unnecessarily, it is necessary to make the cathode electrode part have a complicated structure.

Therefore, recently, a wafer plating apparatus has been considered in which the periphery of the surface to be plated of the wafer is placed in close contact with the upper surface of the cup and the cathode electrode portion has a simple structure. FIGS. 3A and 3B show such a conventional wafer plating apparatus. In this wafer plating apparatus, a cup 2 is provided in the plating tank 1. The cup 2 has a structure in which a ring-shaped rubber sheet 2a is provided on the upper surface of the cup body. The thickness of the rubber sheet 2a is uniform throughout when no load is applied. The plating tank 1 and the cup 2 are connected by a liquid path 3. In the liquid passage 3, the plating liquid (including ionized gold) 4 contained in the plating tank 1 is jetted into the cup 2 from the plating liquid jet port 5 provided at the center of the bottom of the cup 2. A jet pump 6 for interposing is provided. A net-shaped anode electrode 7 is provided at the bottom of the cup 2. The anode electrode 7 is connected via a lead wire 8 to an anode of a power supply device (not shown). The plating solution outflow holes 9 are radially provided at a large number of places on the upper wall portion of the cup 2 that are spaced at equal intervals. Cathode electrodes 10 each having a substantially L-shaped side surface are provided with their ends located outside the inner peripheral end of the rubber sheet 2a by a predetermined distance at predetermined three positions on the upper surface of the rubber sheet 2a. It is provided in a fixed state. The cathode electrode 10 is connected to the cathode of the power supply device via a lead wire 11.

The periphery of the lower surface (surface to be plated) of the wafer 12 is arranged in close contact with the upper surface of the rubber sheet 2a and the predetermined upper surfaces of the three cathode electrodes 10. In this case, although not shown, the wafer 12 is pressed by a leaf spring provided on the lower surface of the upper lid attached to the upper portion of the plating tank 1. Therefore, when the wafer 12 presses the cathode electrode 10, the cathode electrode 10 bites into the rubber sheet 2a while elastically deforming it, and the periphery of the lower surface of the wafer 12 is brought into close contact with the upper surface of the rubber sheet 2a, and the space between It is liquid tight. Although not shown in detail in the wafer 12, as described above, since the opening is formed in the plating resist layer formed on the lower surface (bump electrode formation surface), the opening is formed through this opening. The pad portion is exposed, and a plating connection terminal is further provided at a portion in contact with a predetermined upper surface of the cathode electrode 10.

Then, when the jet pump 6 of the wafer plating apparatus is driven, the plating solution 4 contained in the plating tank 1 is jetted into the cup 2 from the plating solution jet port 5 through the anode electrode 7. , Is sprayed on the central portion of the lower surface of the wafer 12. The plating solution 4 sprayed on the central portion of the lower surface of the wafer 12 radially flows outward along the lower surface of the wafer 12 as indicated by an arrow in FIG. It flows out from the outflow hole 9 and is collected in the plating tank 1. At this time, when a plating current is passed between the anode electrode 7 and the cathode electrode 10, the pad portion exposed on the lower surface of the wafer 12 is gold-plated, and the bump electrode is formed by this gold plating.

By the way, in this wafer plating apparatus, since the periphery of the lower surface of the wafer 12 is brought into close contact with the upper surface of the rubber sheet 2a to make the space between them liquid-tight, it is possible to prevent the plating liquid 4 from flowing out during this period. In addition, since the end of the cathode electrode 10 is located outside the inner peripheral end of the rubber sheet 2a by a predetermined distance, it is possible to prevent the cathode electrode 10 from contacting the plating solution 4 at all. . As a result, it is possible to prevent the cathode electrode 10 provided on the upper surface of the cup 2 from coming into contact with the plating solution 4 and being plated, and also the portion of the cathode electrode 10 can have a simple structure. Further, the plating solution 4 is jetted into the cup 2 from the plating solution jet port 5 provided at the center of the bottom of the cup 2 and is also discharged from a large number of mesh solution outflow holes 9 radially provided on the upper wall of the cup 2. Therefore, the new plating liquid 4 can be constantly supplied to the lower surface of the wafer 12.

[0008]

[Problems to be solved by the device]

 However, in such a conventional wafer plating apparatus, the recovery of the plating solution 4 is performed through a large number of plating solution outflow holes 9 provided radially on the upper wall of the cup 2, so that each plating solution outflow hole is formed. The flow of the plating solution 4 passing through 9 is relatively slow, while there is a certain distance between the adjacent plating solution outflow holes 9. Therefore, for example, as shown in FIG. Bubbles 13 are likely to stay in the middle portion of the liquid outflow hole 9, and there is a certain distance between the upper surface of the rubber sheet 2a and the plating solution outflow hole 9. Therefore, bubbles are easily retained in this portion as well. In addition, it is difficult to eliminate the bubbles existing in the above-mentioned portion from the beginning, and it is possible to completely remove the bubbles in the plating solution 4 contacting the lower surface of the wafer 12. Can not be done, plating failure occurs There was a problem in that it may become is. An object of the present invention is to provide a wafer plating apparatus capable of completely removing air bubbles in the plating solution which are in contact with the lower surface of the wafer.

[0009]

[Means for Solving the Problems]

 This invention is a plating apparatus for a wafer in which the periphery of the surface to be plated of the wafer is placed in close contact with the upper surface of the cup on which the plating solution is jetted, and a plating solution outlet is provided in a region of the upper surface of the cup. In addition to the provision, a plating solution jet port is provided at the bottom of the cup on the side facing the plating solution outlet.

[0010]

[Action]

 According to this invention, the plating solution jetted into the cup from the plating solution jet port flows along the surface to be plated of the wafer from the side corresponding to the plating solution jet port to the side corresponding to the plating solution outlet. Flow in one direction and overflow from one plating solution outlet. In this case, since there is only one plating solution outlet, the flow of the plating solution through this plating solution outlet is relatively fast, and the plating solution was caused to flow in a predetermined direction along the surface to be plated of the wafer. Since it overflows afterwards, bubbles in the plating solution that are in contact with the lower surface of the wafer can be smoothly removed without being trapped anywhere, so that the bubbles in the plating solution that are in contact with the lower surface of the wafer can be removed. Bubbles can be completely removed.

[0011]

【Example】

 1 (A) and 1 (B) show a wafer plating apparatus according to an embodiment of the present invention. In these figures, parts having the same names as those in FIGS. In the cup 2 in this wafer plating apparatus, a substantially C-shaped rubber sheet 2a is provided on the upper surface of the cup body, and the plating solution outlet 21 is provided in one region by the portion where the rubber sheet 2a is not provided. It has a structured structure. A plating solution jet port 5 is provided at the bottom of the cup 2 on the side facing the plating solution outlet 21.

When the jet pump 6 of this wafer plating apparatus is driven, the plating solution 4 contained in the plating tank 1 is jetted into the cup 2 from the plating solution jet port 5 through the anode electrode 7. , Is sprayed onto one end of the lower surface of the wafer 12 (for example, the portion at 9 o'clock in FIG. 1B). The plating solution 4 sprayed onto one end of the lower surface of the wafer 12 is, for example, as shown by an arrow in FIG. 1B, the plating solution 4 from the side corresponding to the plating solution jet port 5 along the lower surface of the wafer 12. It flows in one direction toward the side corresponding to 21 and overflows from one plating solution outlet 21 and is collected in the plating tank 1. At this time, when a plating current is passed between the anode electrode 7 and the cathode electrode 10, the pad portion exposed on the lower surface of the wafer 12 is gold-plated, and the bump electrode is formed by this gold plating.

As described above, in this wafer plating apparatus, the plating solution 4 jetted from the plating solution jet port 5 into the cup 2 is plated from the side corresponding to the plating solution jet port 5 along the lower surface of the wafer 12. It flows in one direction toward the side corresponding to the liquid outlet 21, and overflows from one mesh liquid outlet 21. In this case, since the plating solution outlet 21 is one, the flow of the plating solution 4 through the plating solution outlet 21 is relatively fast, and the plating solution 4 is provided along the surface to be plated of the wafer 12 at a predetermined level. Since it flows in one direction and then overflows, the bubbles in the plating solution 4 that are in contact with the lower surface of the wafer 12 can be smoothly removed without staying anywhere, and therefore the lower surface of the wafer 12 can be contacted. It is possible to completely remove the air bubbles in the plating liquid 4 that are being formed, and thus prevent defective plating from occurring.

Although the upper surface of the cup 2 is horizontal in the above embodiment, the upper surface of the cup 2 may be inclined to a certain extent with the plating solution outlet 21 located at the uppermost position as shown in FIG. 2, for example. Good. In this way, the bubbles that tend to move upward in the plating solution 4 can be eliminated more smoothly.

[0015]

[Effect of device]

 As described above, according to the present invention, the plating solution jetted into the cup from the plating solution jet port is flowed along the surface to be plated of the wafer in a predetermined direction at a relatively high flow rate, and then one plating is performed. Since it overflows from the liquid outlet, the bubbles in the plating solution that are in contact with the lower surface of the wafer can be smoothly removed without staying anywhere, and therefore the plating that is in contact with the lower surface of the wafer can be removed. It is possible to completely remove the air bubbles in the liquid and prevent defective plating from occurring.

[Brief description of drawings]

1A is a sectional view of a wafer plating apparatus according to an embodiment of the present invention, and FIG. 1B is a partial plan view thereof.

FIG. 2 is a sectional view of a wafer plating apparatus according to another embodiment of the present invention.

FIG. 3A is a cross-sectional view of a conventional wafer plating apparatus,
(B) is a plan view of a part thereof.

[Explanation of symbols]

 1 plating tank 2 cup 4 plating liquid 5 plating liquid jet 12 wafer 21 plating liquid outlet

Claims (2)

[Scope of utility model registration request] 1. A wafer plating apparatus in which a periphery of a surface to be plated of a wafer is arranged in close contact with an upper surface of a cup on which a plating solution is jetted, and a plating solution outlet is provided in a region of an upper surface of the cup. A plating apparatus for a wafer, wherein the plating solution jetting port is provided at the bottom of the cup on the side facing the plating solution outlet. 2. The wafer plating apparatus according to claim 1, wherein an upper surface of the cup is inclined such that the plating solution outlet is located at an uppermost position.