JP2002343744A - Plating method and plating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plating method and a plating device which can improve a process capability when bump electrodes are formed by a non-electrolytic plating method. SOLUTION: As shown in a processing step 11, plating solution in a plating bath is under a high pressure condition different from a normal pressure condition. Then, a plating solution temperature is elevated in order to increase a plating speed (processing step 12). For instance, the temperature of plating solution for Ni-plating is kept at about 90 deg.C at first, and then elevated further by a temperature of 20-30 deg.C under the high pressure condition. If the temperature of the plating solution is elevated under a normal pressure condition, the pressure of the plating solution reaches a vapor pressure easily and vaporization of the plating solution is accelerated. On the other hand, if the temperature is elevated under a high pressure condition, a vapor pressure is elevated and the vaporization of the plating solution is suppressed. Non-electrolytic plating electrode members are formed on a plurality of wafers in a processing environment as above described (processing step 13).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device, and more particularly to a method and apparatus for forming a bump electrode by electroless plating.

[0002]

2. Description of the Related Art As the degree of integration of semiconductor integrated circuits increases and the size of semiconductor chips decreases, mounting technology that can support terminal connection at a fine pitch is required. As a mounting technology that can easily respond to this request, there is a TAB (Tape Automate Bonding) mounting used for a TCP (Tape Carrier Package) or the like.

In TAB mounting, lead terminals are connected to bump electrodes. The bump electrode is typically an Au bump, and is generally formed by an electrolytic plating method. A method for forming an Au bump electrode by an electrolytic plating method will be described below.

[0004] For example, an Al pad connected to an internal semiconductor element exposes the surface of an electrical connection region, and the periphery is covered with a passivation film. First, a barrier metal layer and a protective metal layer are stacked, that is, an under bump metal layer is formed by a sputtering method. Thereafter, a resist for bump formation is formed by exposing the electrical connection region of the Al pad and its peripheral portion by photolithography. next,
In accordance with the pattern of this resist, A
u is plated and grown. Thereafter, the under bump metal layer is wet-etched using the Au grown by plating after removing the resist as a mask (for the number of types of layers). Thereafter, an Au bump is formed through annealing or the like. A washing step is appropriately performed in each place.

[0005]

However, the process of forming a bump by the above-described electrolytic plating method is long, and further reduction and rationalization are required. Therefore, recently, formation of a bump electrode by an electroless plating method has been proposed. For the bump electrode formed by the electroless plating method, the sputter formation and etching of the under bump metal layer can be omitted. Further, the omission of formation of a resist for plating growth can be expected. For these reasons, attention has been paid to the fact that the process can be significantly shortened, and the formation of a bump electrode that is inexpensive and has a short delivery time is realized.

[0006] In forming a bump electrode by electroless plating, the plating deposition rate depends to some extent on the temperature of the plating solution. Unless the plating solution temperature is high to some extent, a plating deposition rate suitable for mass production cannot be obtained. However, when the temperature of the plating solution is high, there is a problem that the plating solution itself evaporates quickly, the composition changes remarkably, and the quality of the deposited plating metal deteriorates.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a plating method and a plating apparatus capable of improving a processing capability in forming a bump electrode by electroless plating.

[0008]

According to the plating method of the present invention, a plating solution is set at a predetermined temperature while being kept under a high pressure condition different from normal pressure, and a plurality of plating solutions immersed in the plating solution are set. An electroless plating electrode member is formed on the wafer.

According to the plating method of the present invention, the vapor pressure can be increased by placing the plating solution under high pressure. This makes it possible to perform plating at a higher temperature while suppressing the deterioration of the composition of the plating solution, thereby contributing to an improvement in processing efficiency.

[0010] A plating apparatus according to the present invention is provided with a plating tank provided with a heating mechanism, wherein a plating solution is brought to a predetermined temperature range, a pressure chamber containing the plating tank and keeping the plating solution under high pressure conditions, It is characterized by having.

According to the plating apparatus of the present invention, the plating solution can be kept under high pressure by the pressure chamber in which the plating tank is housed. As a result, the vapor pressure of the plating solution is increased, and plating at a higher temperature can be performed, thereby contributing to an improvement in processing efficiency.

[0012]

FIG. 1 is a flowchart showing a plating method according to an embodiment of the present invention. As shown in processing step 11, the plating solution in the plating tank is placed under high-pressure conditions different from normal pressure (for example, about 200 to 500 kPa). Thereafter, the plating solution temperature is increased so as to increase the plating rate (processing step 12). For example, the plating solution for Ni plating is initially set to about 90 ° C., and is further increased by 20 to 30 ° C. when the pressure is reduced. Increasing the plating solution temperature at normal pressure easily reaches the vapor pressure and promotes evaporation. However, under high pressure conditions, the vapor pressure is increased, thereby suppressing the evaporation of the plating solution. .
Electroless plated electrode members are formed on a plurality of wafers at high speed in such a processing environment (processing step 13).

According to the above plating method, the plating solution can be kept at a higher temperature than at normal pressure and in a stable state that is hardly evaporated. Therefore, the composition of the plating solution is hardly deteriorated. This enables plating at a high temperature, which contributes to an improvement in processing efficiency.

FIG. 2 is a schematic view showing the configuration of a plating apparatus according to one embodiment of the present invention. The plating tank 21 is provided with a heating mechanism 22 such as a heater, and the temperature of the plating solution 23 is controlled within a predetermined range. This plating tank 2
The pressure chamber 24 in which 1 is accommodated is controlled so that the plating solution 23 is under a high pressure condition (for example, about 200 to 500 kPa). For example, N ₂ gas is supplied into the chamber 24 by a compressor (not shown) and pressurized.

In the plating tank 21, for example, a plurality of wafers W
A Teflon (registered trademark) basket 25 in which F is set is put in, and immersed in the plating solution 23. For example,
The plating solution 23 for Ni plating is initially set at about 90 ° C., and is further raised by 20 to 30 ° C. when the pressure is lowered by the pressure chamber 24. A connection portion for controlling the heating mechanism 22 is provided at the bottom or side portion in the pressure chamber 24, and the temperature of the plating solution can be adjusted. When the pressure chamber 24 is set to a high pressure condition, the vapor pressure is increased, so that the evaporation of the plating solution 23 can be suppressed even if the temperature of the plating solution 23 is increased. An electroless plating electrode member is formed on a plurality of wafers at high speed in such a processing environment.

According to the configuration of the above embodiment, the plating tank 2
The plating solution 2 is formed by the pressure chamber 24 in which the plating solution 2 is accommodated.
3 can be subjected to high pressure conditions. As a result, the vapor pressure of the plating solution 23 is increased, and plating at a higher temperature can be performed, which contributes to an improvement in processing efficiency.

In the above embodiment, the control of the pressure in the pressure chamber or the adjustment of the temperature of the plating solution is performed as follows.
The present invention is not limited to this, and high quality and high plating rate conditions may be selected according to the metal to be subjected to electroless plating.

[0018]

As described above, according to the present invention, the vapor pressure can be increased by placing the plating solution under high pressure. This makes it possible to perform plating at a higher temperature while suppressing the deterioration of the composition of the plating solution, thereby contributing to an improvement in processing efficiency. As a result, it is possible to provide a plating method and a plating apparatus capable of improving a processing capacity in forming a bump electrode by electroless plating.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a plating method according to an embodiment of the present invention.

FIG. 2 is a schematic view illustrating a configuration of a plating apparatus according to an embodiment of the present invention.

[Explanation of symbols]

 11 to 13 Processing Step 21 Plating Tank 22 Heating Mechanism 23 Plating Solution 24 Pressure Chamber 25 Basket WF Wafer

Claims (2)

[Claims] An electroless plating electrode member is formed on a plurality of wafers immersed in the plating solution while the plating solution is set at a predetermined temperature while being subjected to a high-pressure condition different from normal pressure. A plating method characterized by the following. 2. A plating tank provided with a heating mechanism, wherein a plating solution is heated to a temperature within a predetermined range, and a pressure chamber containing the plating bath and keeping the plating solution under high pressure. And plating equipment.