JPH07216585A - Plating device - Google Patents

Abstract

PURPOSE:To enable easy removing of air bubbles on a substrate surface and at a resist opening at the time of plating, that is, airs existing in a plating solution at the early time of plating and gases generated in an electrochemical reaction in a plating device for the substrate. CONSTITUTION:An opening surface of a cup 2 in which the plating solution 12 flows is positioned downward and a cathode electrode 7 brought into contact with a connecting terminal for plating of the substrate 11 supported with the surface to be plated directed upward is provided at the downward opening surface of the cup 2. Further, a substrate supporting base 1 supporting the substrate 11 with the surface to be plated directed upward while being joinable with and separable from the downward opening surface of the cup 2 is provided. An anode electrode 4 is provided above the substrate 1 in the cup 2 and a plating solution supplying means (a tank 13 and a pump 14) for feeding the plating solution 12 is provided. Further, a substrate attracting means (a suction path 3) attracting the substrate 11 to the surface of the substrate supporting base 1 is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate plating apparatus for plating a semiconductor substrate.

[0002]

2. Description of the Related Art For example, when a bump electrode is formed on a semiconductor substrate (hereinafter simply referred to as a substrate), a plating resist layer is formed on the bump electrode formation surface (surface to be plated) of the substrate, and the plating resist layer is etched. By forming an opening, the pad portion is exposed from the opening, and the exposed pad portion is plated with gold or the like by using a plating device, and the bump electrode is formed by the plating.

FIG. 2 shows a conventional substrate plating apparatus used for forming bump electrodes on such a substrate. In this substrate plating apparatus, a cup 22 is provided in the plating tank 21 as shown in the drawing,
The plating tank 21 and the cup 22 are connected by a liquid path 23. A jet pump (not shown) for jetting the plating liquid (including ionized gold) 24 contained in the plating tank 21 into the cup 22 is interposed in the liquid passage 23.

A net-shaped anode electrode 25 is provided at the bottom of the cup 22, and the anode electrode 25 is connected to an anode 27 of a power supply device (not shown) via a lead wire 26. Cathode electrodes 28, 28, 28 are provided at predetermined three locations on the upper surface of the cup 22 that are spaced at equal intervals, and the cathode electrodes 28 are connected to the cathode 30 of the power supply device via the lead wires 29. ing.

The above three cathode electrodes 28, 28, 2
A substrate 31 is mounted on the substrate 8. Although not shown in detail in the substrate 31, as described above, the opening is formed in the plating resist layer (not shown) formed on the bump electrode formation surface (lower surface in the drawing),
The pad portion is exposed from the opening, and further, a plating connection terminal (not shown) is provided in a portion in contact with the cathode electrodes 28, 28, 28. The substrate 31 is pressed down by a leaf spring (not shown) provided on the lower surface of an upper lid (not shown) attached to the plating tank 21.

When the jet pump of this substrate plating apparatus is driven, the plating solution 24 contained in the plating tank 21 is jetted into the cup 22 through the anode electrode 25, and the bottom surface of the substrate 31 is jetted. Be sprayed on. At this time, when a plating current is passed between the anode electrode 25 and the cathode electrode 28, the pad portion exposed on the lower surface of the substrate 31 is plated with gold, and the bump plating is formed by the plated gold. The plating liquid 24 sprayed on the lower surface of the substrate 31 overflows from the cup 22 to the outside, flows down, and is collected in the plating tank 21.
In this case, the plating liquid 24 overflows from the cup 22 and flows down to the substrate 3
This is because a new plating liquid 24 is constantly supplied to the lower surface of No. 1.

[0007]

However, in the conventional plating apparatus for a substrate as described above, since the substrate 31 is set with the bump electrode forming surface of the surface facing downward, the plating solution 24 is spouted. At this time, bubbles (air) in the plating solution 24 are accumulated on the surface of the substrate 31 and the resist opening, which makes it impossible to perform stable bump plating. In addition, the gas generated in the electrochemical reaction during the electrolytic deposition of the plating metal is also accumulated in the resist opening and the surface of the substrate 31, which hinders the formation of bump plating.

Further, as a method of removing the air bubbles accumulated on the downward surface of the substrate 31, the flow rate of the plating solution 24 is increased while the plating current is stopped during the plating, and the air bubbles accumulated on the surface of the substrate 31 (air, (Gas) can be removed, but this still has the drawback that gas and air cannot be completely removed. At this time, unless the plating current is stopped during the plating to increase the flow rate of the plating solution 24, the plating grows abnormally in the flow direction.

Therefore, the plating time becomes longer than the original plating time (the time taken by dividing the thickness by the deposition rate) by executing the bubble removal sequence, and there is a drawback that the efficiency is poor. Furthermore, solder bump plating has a drawback that the current density must be extremely reduced in order to suppress the generation of bubbles.

Therefore, an object of the present invention is to easily remove air bubbles on the surface of the substrate and the resist opening during plating, that is, air in the plating solution at the initial stage of plating and gas generated during the electrochemical reaction, An object of the present invention is to provide a plating apparatus capable of improving the efficiency of plating and reducing the total amount of liquid.

[0011]

In order to solve the above problems, the present invention provides an anode electrode and a cathode electrode in a cup into which a plating solution is introduced, and the cathode electrode is brought into contact with a connection terminal for plating provided on a substrate. In a plating device that performs plating on the surface to be plated of the substrate in such a state, for example,
At the bottom of the cup with the opening face downward, contact the substrate support part supporting the substrate with the plated surface facing upward, and the plating connection terminal of the substrate supported by the substrate support part The cathode electrode is provided.
The anode electrode is provided above the substrate in the cup, and a plating liquid supply means for introducing the plating liquid is provided.

[0012]

According to the present invention, in the lower part of a cup having a downward opening surface, the substrate is supported with the cathode electrode in contact with the connection terminal for plating with the surface to be plated facing upward, and the plating liquid supply means. By injecting the plating solution above the substrate in the cup, the substrate can be set and plated with the surface to be plated facing upward, so that bubbles easily escape upward from the surface of the substrate and the resist opening. That is, the air in the plating solution at the initial stage of plating easily escapes upward from the substrate, and the gas generated during the electrochemical reaction also easily escapes upward.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the plating apparatus according to the present invention will be described below with reference to FIG.

FIG. 1 shows a substrate plating apparatus as an example to which the present invention is applied. 1 is a substrate support, 2 is a cup, 3 is a suction passage, 4 is an anode electrode, 5 is an anode, and 6 is Sealing sheet, 7 is a cathode electrode, 8 is a cathode, 9 is a guide ring, 10 is an O-ring, 11 is a substrate, 12 is a plating solution, 13 is a tank, 14 is a pump, 15 is a supply path, 16
Is a discharge passage, 17 is a relief valve, and 18 is a return passage.

In this substrate plating apparatus, as shown in the figure, a cup 2 is provided on the substrate support 1, and the opening surface of the cup 2 faces downward. Substrate support 1
Is movable up and down, and the cup 2 is fixed to the main body of the plating apparatus (not shown).

A suction passage 3 is formed in the substrate support 1, and the suction passage 3 is connected to a suction source (not shown), for example, a vacuum pump, via a lower pipe passage 3a. On the upper surface of the substrate support base 1, a large number of suction ports 3 opening upward
b, 3b, 3b, ... Are formed, and these suction ports 3 are formed.
Around the substrate supporting surface where b, 3b, 3b, ... Are opened, there is formed a male taper-shaped inclined engaging surface 1a for centering when the cup 2 is combined.

A net-shaped anode electrode 4 is provided in the upper part of the cup 2 having an opening face downward, and the anode electrode 4 is connected to an anode 5 of a power supply device (not shown). A ring-plate-shaped sealing sheet 6 made of elastic viton rubber is provided around the downward opening surface of the cup 2. Plate-shaped cathode electrodes 7, 7, 7 are provided at predetermined three positions on the lower surface of the hermetically sealed sheet 6 which are spaced at equal intervals (center angle 120 °). The cathode electrode 7 is connected to the cathode 8 of the power supply device.

Further, a guide ring 9 is superposed on and integrated with the lower surface of the sealing sheet 6. That is, for example, at equal intervals (center angle 1) around the downward opening surface of the cup 2.
20 [deg.] Each, and at three locations spaced apart from each other, the positioning projections 2a,
2a, 2a are formed, and the alignment projection 2
Corresponding to a, 2a, 2a, through holes 6a, 6a, 6a for alignment in the sealing sheet 6, through holes 7a, 7a, 7a for alignment in the cathode electrodes 7, 7, 7 and guide ring 9
Positioning recesses 9a, 9a, 9a are formed on the upper surface, respectively.

These alignment projections 2a, 2a, 2a
Through the positioning through holes 6a, 6a, 6a and the positioning through holes 7a, 7a, 7a, respectively, and further,
The sealing sheet 6 and the cathode electrodes 7, 7, 7 are fixed to the cup 2 by using the guide ring 9 by engaging with the positioning recesses 9a, 9a, 9a, respectively. The inner peripheral side of the guide ring 9 is a female taper shape for centering when it is combined with the substrate support base 1 so as to engage with the male taper-shaped inclined engagement surface 1a formed on the cup 2. Is an inclined engagement surface 9b.

In such an assembled state of being integrated with the cup 2 side, the cathode electrodes 7, 7, 7 are exposed to the inside of the guide ring 9 by about 3 to 4 mm, and other portions are It is completely covered with the sealing sheet 6 and the guide ring 9, so that plating metal is not deposited on this portion. That is, since the tips of the cathode electrodes 7, 7, 7 are located outside the inner peripheral edge of the sealing sheet 6 by a predetermined distance, the inner peripheral edge of the sealing sheet 6 is the cathode electrode 7 of the plating solution 12. , 7, 7 is blocked from flowing in the direction in which the cathode electrodes 7, 7, 7 are located, and the cathode electrodes 7, 7, 7 can be prevented from coming into contact with the plating solution 12 at all. An O-ring 10 is provided between the lower surface of the guide ring 9 and the substrate support base 1 to interpose therewith.

Here, since the substrate 11 has a large number of openings 11c, 11c, 11c, ... Formed in the plating resist layer 11b formed on the metal layer 11a formed on the bump electrode forming surface, Openings 11c, 11c, 1
1c, ..., The pad portion is exposed, and further, a plating connection terminal (not shown) formed by a part of the metal layer 11a is provided at a portion in contact with the tip portions of the three cathode electrodes 7, 7, 7. Has become.

A tank 13 for storing the plating solution 12 flowing into the cup 2 is prepared, and the tank 13 is arranged below the cup 2. Further, a pump 14 for pumping the plating solution 12 from the tank 13 is prepared, and a supply path 15 through which the plating solution 12 discharged from the pump 14 flows is connected to a lower portion of the cup 2 and opens into the cup 2. ing.

In the upper part of the cup 2 and in the substantially central part,
A discharge path 16 is provided. A relief valve 17 is provided outside the cup 2 in the discharge passage 16, and a return passage 18 branched from the front side of the relief valve 17 is connected to the relief valve 17. This return path 18
It is connected to the inside of the tank 2.

When the bump electrodes are formed on the substrate 11 by using the substrate plating apparatus having the above-described structure, first, the substrate support 1 is lowered from the cup 2 to a separated state, and the substrate support 1 The substrate 11 is set on the substrate supporting surface with the surface to be plated, which is the surface of the substrate 11, facing upward. Then, by operating the vacuum pump which constitutes the substrate suction means, the suction port 3 is passed through the suction line 3 and the suction ports 3b, 3b, 3 through the pipe 3a.
By applying a suction force to b, ...
It is adsorbed and fixed on the substrate supporting surface of.

Subsequently, the substrate support base 1 on which the substrate 11 is fixed in this way is raised, and the male taper-shaped inclined engagement surface 1a provided for centering the substrate support base 1 is integrated with the cup 1. The guide ring 9 is engaged with the female taper-shaped inclined engagement surface 9b provided for centering, and the O-ring 10 is interposed between the lower surface of the guide ring 9 and the substrate support 1. At this time, the inside of the cup 2 is the sealing sheet 6 and the O-ring 1.
It is completely sealed with 0. Further, almost the periphery of the substrate 11 is in close contact with the lower surface of the sealing sheet 6, and the plating connection terminals formed by a part of the metal layer 11a of the substrate 11 are connected to the cathode electrodes 7, 7, 7, respectively.

Next, the plating liquid 12 is supplied from the supply passage 15 into the cup 2 by driving the pump 14 constituting the plating liquid supply means. The plating solution 12 flows into the upper part of the substrate 11, its liquid level gradually rises, and the relief valve 17 is closed.
The air in the tank 1 passes from the discharge path 16 to the return path 18
It is sent to the inside of 3 and opened to the outside, and the piping system is free of air. In addition, the resist openings 11c, 11 of the substrate 11
With respect to the gases generated in c, 11c, ..., Since the surface of the substrate 11 (the surface to be plated) faces upward, the gas is likely to escape above the resist openings 11c, 11c, 11c ,.

In the above state, when a plating current is passed between the anode electrode 4 and the cathode electrodes 7, 7, 7, the substrate 11
The pad portions exposed in the resist openings 11c, 11c, 11c, ... On the upper surface of the are plated, and bump electrodes are formed by the plated metal. In this way, since the substrate 11 can be set and plated with the surface to be plated facing upward, it is possible to prevent bubbles in the plating solution 12 from being lifted and removed, thereby preventing defective plating.

After the plating is completed, the relief valve 17 is opened to open the discharge passage 16 and the return passage 18 to the atmosphere, so that the plating passage 12 in the return passage 18 is recovered in the tank 13 and the tank 13 is removed. Since it is located below the cup 2, the plating solution 1 in the cup 2
2 is collected in the tank 13 via the supply passage 15 and the pump 14. After that, the substrate support base 1 is moved down to release the suction fixing of the substrate 11 on the substrate support surface, and the substrate 11 after the plating process is taken out.

In the above embodiment, the tank is arranged below the cup, and after the plating is completed, the plating liquid is collected in the tank by opening the inside of the cup to the atmosphere. The present invention is not limited to this, and the plating liquid in the cup may be collected in the tank by suction. Further, in the embodiment, the cup is fixed and the substrate support is movable up and down, but the substrate support may be fixed and the cup is movable up and down, or both the substrate support and the cup are vertically moved. It may be movable. Furthermore, the number of cathode electrodes and the like are arbitrary, and it is needless to say that the specific detailed structure and the like can be appropriately changed.

[0030]

As described above, according to the plating apparatus of the present invention, the substrate can be set and plated with the surface to be plated facing upward, and the bubbles escape upward from the surface of the substrate and the resist opening. Since it is easy, the air in the plating solution at the initial stage of plating and the gas generated during the electrochemical reaction can be easily removed. Therefore, as in the past,
For example, in solder bump plating or the like, the current density had to be extremely reduced in order to suppress bubble generation, but bump electrodes can be formed without worrying about bubble generation even at high current densities. Therefore, the efficiency of plating and the reduction of the total amount of liquid can be achieved at the same time.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional side view showing a substrate plating apparatus as an example to which the present invention is applied, and is a schematic configuration diagram also showing configurations of a pipe, a plating solution tank, and the like.

FIG. 2 is a vertical cross-sectional side view showing a main part of a conventional substrate plating apparatus used when forming bump electrodes on a substrate.

[Explanation of symbols]

 1 Substrate support 2 Cup 3 Suction path 4 Anode electrode 6 Sealing sheet 7 Cathode electrode 9 Guide ring 10 O-ring 11 Substrate 12 Plating solution 13 Tank 14 Pump 15 Supply path 16 Discharge path 17 Relief valve 18 Return path

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location H05K 3/24 A 7511-4E

Claims (1)

[Claims] 1. Plating for plating a surface to be plated of a substrate in a state where an anode electrode and a cathode electrode are provided in a cup into which a plating solution is introduced, and the cathode electrode is in contact with a plating connection terminal provided on the substrate. In the device, a substrate support part supporting the substrate with the surface to be plated facing upward and the cathode electrode to be brought into contact with the plating connection terminal of the substrate supported by the substrate support part are provided under the cup. A plating apparatus, wherein the anode electrode is provided above the substrate in the cup, and a plating solution supply unit for introducing the plating solution is provided.