JPH05171500A - Method and device for plating - Google Patents

Abstract

PURPOSE:To obtain a high-quality plating and to improve the productivity of this plating soln.-circulating plating device by removing the deposit, precipitate, particles, etc., in the soln. CONSTITUTION:A plating soln. 18 is forcedly sent under pressure from a storage tank 11 to a plating tank 15 provided with a plating cup 14 for carrying and fixing a material 2 to be plated and recovered in the tank 11, in this plating soln.-circulating plating device. A filter part 4 in which a meshy filter having a specified mesh size to block a plating soln. passage is provided on the delivery side of a jet pump 12 for forcedly circulating the soln. 18 in the tank 11 under pressure into the cup 14 and on the delivery side of circulating pumps 11b and 15b furnished to a plating soln. circulating pipe outside the outer walls of the tank 11 or 15 or both.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plating apparatus and a plating method for supplying a circulating plating solution to the surface of an object to be plated and subjecting the object to be plated to a required plating treatment. TECHNICAL FIELD The present invention relates to a plating apparatus and a plating method for improving productivity by efficiently removing foreign matters and particles contained in a plating solution and foreign matters and particles contained in the plating solution, and performing plating treatment with excellent quality.

For example, when a bump made of gold (Au) or solder is formed as an external connection electrode in a semiconductor integrated circuit, or a metal layer is formed during a thin film plating process of a circuit board such as a printed board or a multilayer ceramic board. In some cases, a plating solution circulation type plating device is often used.

[0003]

2. Description of the Related Art FIG. 2 is a conceptual diagram for explaining a conventional plating apparatus together with a plating method. In the figure, a case of forming the above-mentioned bumps on an integrated circuit substrate will be described as an example.

In FIG. 2, which is a side sectional view, a plating apparatus 1 includes a storage tank 11 for storing a plating solution and a plating cup 14 connected to the storage tank 11 by a plating solution supply pipe 13 via a jet pump 12. A plating treatment tank 15 for receiving the plating solution overflowing from the plating cup 14 is configured as a main member, and the plating solution stored in the plating treatment tank 15 is stored in the storage tank 11 by a reflux pipe 16. It is configured to be collected.

The opening end face located above the plating cup 14 is configured so that the integrated circuit board 2 as the object to be plated can be positioned and fixed with the plating liquid overflow passage secured. In addition, between the bump forming electrode of the integrated circuit substrate 2 fixed to the opening end face and the plating solution, a contact needle 14a for contacting a conductor connected to the electrode and a plating needle 14 are disposed inside the plating cup 14. A desired potential is applied by a potential circuit 17 formed with the anode 14b.

Therefore, the required integrated circuit substrate 2 is mounted and fixed on the opening end surface of the plating cup 14 with its bump forming surface facing downward, and each bump forming electrode of the substrate 2 and the inside of the plating cup 14 are fixed. Between the anode 14b located at
When the plating liquid 18 filled in the liquid storage tank 11 is supplied to the plating cup 14 by the jet pump 12 as indicated by an arrow A shown by a solid line in a state where an electric potential of about 3 V is applied, the plating liquid 18 overflows from the plating cup 14. A desired bump can be formed by a plating layer on each bump forming electrode of the integrated circuit board 2.

The plating liquid overflowing from the plating cup 14
Since 18 is collected in the liquid storage tank 11 through the reflux pipe 16 as indicated by an arrow B indicated by a broken line, efficient plating processing by circulating the plating liquid 18 can be continuously performed.

[0008]

[Problems to be Solved by the Invention] However, for example, gold (Au)
When the bumps are formed by plating, gold in the plating solution may be deposited and atomized in the solution, and when the bumps are formed by solder plating, the plating solution may contain, for example, phenol sulfonic acid Pb, phenol sulfonic acid Sn, or phenol sulfonic acid. Precipitation of Pb or Sn may occur after the preparation of the liquids because multiple types of mixed liquids containing acids, additives, etc. are used.

Particles in the plating solution, which also include substances mixed from the outside, circulate in the plating apparatus together with the above-mentioned deposits and deposits. Then, these circulating precipitates, precipitates, particles and the like may be carried to the surface of the integrated circuit board 2 together with the plating solution and further adhere to the surface of the board 2.

When the adhered fine particles are conductors, projections centered on the fine particles are formed on the plated surface, and when the fine particles are non-conductive, no plating layer is formed on the fine particles, and therefore the plated surface is pinned. Although a dent like a hole is formed, such a protrusion or dent on the plated surface induces a decrease in the connectivity with external terminals such as leads after that, and at the same time, a degradation in the connection reliability over a long period of time. .

Therefore, in the plating method using the plating apparatus having the conventional structure, the plating surface is likely to have irregularities due to deposits, precipitates, particles, etc. contained in the plating solution, resulting in reliability of connection with external terminals such as leads. However, there was a problem that the productivity could not be expected to be improved.

[0012]

[Means for Solving the Problems] The above-mentioned problem is that the plating liquid pumped from the liquid storage tank is recovered in the liquid storage tank through a plating tank equipped with a plating cup for mounting and fixing an object to be plated. A circulating plating apparatus, in which the plating solution in a storage tank is pumped out to a plating cup, and the plating solution in a tank provided outside the side wall of the storage tank or the plating tank or both of them. A filter part having a mesh net of a predetermined mesh roughness capable of blocking the plating solution flow passage is detachably attached to the outflow side of the circulation pump located in the middle of the circulation pipe for forced circulation. This is achieved by the plating equipment being used.

Further, in the above plating apparatus, a circulation pump located in the middle of the circulation pipe for forced circulation of the plating solution in the tank provided outside the side walls of the storage tank or the plating treatment tank or both of them is operated to operate the outflow side thereof. While circulating and filtering the plating solution in the tank with the filter section located at, the jet pump that pumps the plating solution in the storage tank to the plating cup is operated to plate with the plating solution filtered at the filter section located on the outflow side. This is achieved by a plating method in which the object to be plated mounted and fixed on the cup is subjected to the required plating treatment.

[0014]

By providing a filter for removing fine particles in the circulation path of the plating solution, it is possible to almost completely remove deposits, precipitates, particles and the like in the plating solution.

Therefore, in the present invention, a plating device is constructed by disposing a filter for removing fine particles, which is attachable / detachable, in the vicinity of the jet pump and / or the liquid storage tank and / or the plating treatment tank.

This means that by circulating the plating solution at all times, the above-mentioned fine particles such as precipitates, precipitates and particles can be removed. Therefore, it is possible to remove the fine particles contained in the plating solution and form a plating layer of excellent quality without unevenness on the surface.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram for explaining a plating apparatus according to the present invention together with a plating method. (1-1) shows an example of the overall structure and (1-2) shows an example of the structure of a filter section according to the present invention. Is an enlarged representation of.

Note that, as in the case of FIG. 2, the case where bumps are formed on the integrated circuit substrate as the object to be plated is shown as an example in the figure, so the same target members as in FIG. 2 are denoted by the same symbols.

The plating apparatus 3 has a structure similar to that of the plating apparatus 1 described with reference to FIG. 2 in (1-1) shown in the same side section as in FIG. Immediately below the plating cup 14 of the plating apparatus 1, that is, immediately after the jet pump 12, in the middle of the plating solution supply pipe 13 and the storage tank 11.
Alternatively, the filter section 4 is additionally attached to the side wall portions of the plating tank 15 or both (both in the figure).

Both the liquid storage tank 11 and the filter portion 4 mounted on the plating tank 15 branch off near the bottom of the liquid tank 11 and the plating tank 15 and then reach the vicinity of the liquid surface of the circulation pipe 11a. Circulation pumps 11b and 15 installed in the middle of
It is arranged in series immediately after b, and the liquid storage tank
11 and the plating solution in the plating tank 15 are pumps 11b and 15b
After being sucked up by, it is filtered by the filter section 4 and returned to the same tank.

Here, a configuration example of the filter unit 4 will be described with reference to (1-2). As described above, the filter portion 4 mounted in the middle of the plating liquid supply pipe 13 and the circulation pipes 11a and 15a.
Is fixed in parallel to the casing 41 so as to block the casing 41 and the casing 41 in which a through hole 41a is formed in the shape of a central axis of the pipe and is approximately equal to the inner diameter of each pipe. 2 filters 42 _-1 , 42 _-2 .

The two filters 42 _-1 , 42 _-2 include two equal filter frames 43 and flange plates of the respective filter frames 43.
43a Two kinds of mesh nets made of a corrosion-resistant metal wire, such as a platinum wire, having different mesh roughnesses, which are tightly fitted in the distal end through-hole region of a long semicircular projection plate 43b protruding to one side.
_-1 , 44 _-2 , for example, a filter 42 _-1 is formed by combining the filter frame 43 and the mesh net 44 _-1, and a filter is formed by combining the filter frame 43 and the mesh net 44 _-2. 42 _-2 are to be constructed.

A ring-shaped packing 43c is mounted on the side of the flange plate 43a of each filter frame 43 on which the protruding plate is formed so as to surround the protruding plate 43b. The filters 42 _-1 , 42 _-2 and the casing 41 are formed through the through holes of the casing 41.
By inserting each of the filters 42 _-1 , 42 _-2 from the tip side of the projecting plate into the groove 41b provided in parallel at two predetermined positions in the direction of blocking the 41b, the positioning of the filters can be performed. In the positioned state, the mesh nets 44 _-1 , 44 _-2 and the through hole 41a of the casing 41 are substantially aligned with each other, and both of them have the ring-shaped packing 43c. It can be fixed while being hermetically closed by means of screwing means.

This means that by releasing the fixing means, the filters 42 _-1 , 42 _{-2 and the} mesh nets 44 _-1 , 44 _{-2 are connected.}
Means that the mesh net which has been clogged can be easily cleaned and replaced.

Therefore, the filter frame 43 is combined with, for example, a mesh net 44 _-1 having a mesh roughness of 5 to 10 μm to filter.
42 _-1 and the filter frame 43 has a mesh roughness of 0.1 to 1.
0 After μm by combining a mesh net 44 _-2 a filter 42 _-2, jet pump 12 or the circulation pump 11b, away from the insertion fixed each pump rough filter 42 _-1 mesh roughness closer to 15b Filter with finer mesh roughness 42
By inserting and fixing _-2 , the plating apparatus 3 shown in (1-1) can be constructed.

Therefore, the circulating pump 11b of the liquid storage tank 11 or the circulating pump 15b of the plating treatment tank 15 or both are operated to filter the plating liquid of the liquid storage tank 11 or the plating treatment tank 15 or both, As described with reference to FIG. 2, the required integrated circuit board 2 is mounted and fixed on the opening end surface of the plating cup 14 with its bump forming surface facing downward.
On the bump forming electrodes of the integrated circuit board 2 by sending the plating liquid 18 from the liquid storage tank 11 to the plating cup 14 by the jet pump 12 while applying a predetermined potential between the bump forming electrodes and the anode 14b. The required bumps can be formed by the plating layer.

In particular, in this case, the deposits and precipitates in the plating solution are filtered by at least a plurality of filter sections 4, and the particles that fly into the storage tank 11 or the plating treatment tank 15 from the outside are also filtered by the plurality of filter sections. Since it can be almost completely removed by 4, it is possible to effectively perform a plating treatment of excellent quality with no surface irregularities,
Since the mesh net that is clogged with precipitates or particles can be easily cleaned, it can be expected to improve productivity.

In the usual plating process described above,
Experimentally confirmed that each particle of the plating solution by combining the mesh net 44 _-1 and the mesh roughness 0.1 to 1.0 [mu] m mesh net 44 _-2 mesh roughness 5~10μm is almost completely removed is doing.

[0029]

As described above, according to the present invention, the deposits and precipitates generated in the plating solution and the particles contained in the plating solution are efficiently removed, and the plating treatment of excellent quality is performed to improve the productivity. It is possible to provide an improved plating apparatus and plating method.

In the description of the present invention, the case where the bumps on the integrated circuit board are formed by plating is taken as an example. However, the mesh of the mesh net of the filter portion provided in the plating apparatus is plated with the plating material, the plating conditions and the object to be plated. The same effect can be obtained by setting in accordance with the size of the.

In the description of the present invention, the filter to be mounted on the filter portion is composed of two mesh nets having different mesh roughness. However, if the mesh net is frequently removed and cleaned, the finer mesh should be used. The same effect can be obtained even with a single filter in which the mesh net is inserted.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a plating apparatus according to the present invention together with a plating method.

FIG. 2 is a conceptual diagram illustrating a conventional plating apparatus together with a plating method.

[Explanation of symbols]

2 Integrated circuit board (object to be plated) 3 Plating device 4 Filter unit 11 Storage tank 11a Circulation pipe 11b Circulation pump 12 Jet pump 13 Plating liquid supply pipe 14 Plating cup 14b Anode 15 Plating tank 15a Circulation pipe 15b Circulation pump 18 Plating Liquid 41 Housing 41a Through hole 41b Groove 42 _-1 , 42 _-2 Filter 43 Filter frame 43a Flange plate 43b Projection plate 43c Ring packing 44 _-1 , 44 _-2 Mesh net

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location C25D 21/06 H01L 21/288 Z 7738-4M 21/321

Claims (4)

[Claims] 1. A plating solution pressure-fed from a liquid storage tank (11).
(18) Mounts and fixes the object to be plated (2) Plating cup (14)
A plating liquid circulation type plating device which is collected in the liquid storage tank (11) through a plating treatment tank (15) equipped with a plating cup (14) ) And the outflow side of the jet pump (12) and the liquid storage tank (11)
Alternatively, the plating solution flow path is blocked from the outflow side of the circulation pump (11b, 15b) located in the middle of the circulation pipe for forced circulation of the plating solution inside the tank, which is provided outside the side walls of the plating tank (15) or both. A plating apparatus comprising a filter section (4) to which a filter having a mesh net having a predetermined mesh roughness that can be attached is detachably mounted. 2. The filter section (4) according to claim 1, wherein the mesh nets (44 _-1 , 44 _-2 ) which are detachable from the filter section (4) and have different mesh roughness are respectively strained. The plating device is characterized in that the two filters (42 _-1 , 42 _-2 ) that are fitted into the plating solution are mounted so that the mesh roughness becomes rough on the plating solution inflow side. 3. The mesh roughness of each of the two filters (42 _-1 , 42 _-2 ) mounted on the filter section (4) according to claim 2 is 5 to 10 μm and 0.1 to 1.0 μm. Plating equipment characterized by being in the range of. 4. The plating apparatus according to claim 1, wherein the tank is located in the middle of a circulation pipe for forced circulation of the plating solution in the tank, which is provided outside the side walls of the liquid storage tank (11) and / or the plating treatment tank (15). The circulating pump (11b, 15b) is operated to circulate and filter the plating solution in the tank with the filter section (4) located on the outflow side, while the plating solution (18) in the storage tank (11) is plated ( The jet pump (12) that pressure-feeds to (14) is operated to apply the plating liquid filtered by the filter section (4) located on the outflow side of the jet pump (12) to the object to be plated (2) mounted and fixed on the plating cup. A plating method characterized by applying a plating treatment.