PLATING DEVICE

Abstract

Provided is a plating process that enables merits of an insoluble anode to be sufficiently enjoyed in a jet type plating equipment. Also provided is a plating equipment having a plating tank including an opening part; a solution supply piping; an insoluble anode; and an diaphragm, an diaphragm outer peripheral end being fixed to a plating tank inner wall, a through-hole being provided in an diaphragm center, a hole peripheral end of the through-hole being fixed to the solution supply piping, the diaphragm being arranged so as to be inclined upward in an outer circumferential direction from the solution supply piping. A silicon ring is firmly fixed to each of the outer peripheral end of the diaphragm and a hole edge of the through-hole of the diaphragm. The solution supply piping supplies the plating solution to an upper catholyte chamber in the plating tank, the upper catholyte chamber being formed by the diaphragm and the placed object to be plated. An annular flow passage including a solution ejection hole in an upper part thereof is provided in an outer circumference of the solution supply piping, and a lower anolyte chamber solution is supplied from the solution ejection hole to a lower anolyte chamber in the plating tank, the lower anolyte chamber being formed below the diaphragm, whereby a flow that moves from around the through-hole of the diaphragm toward the outer circumferential direction of the diaphragm is formed in the lower piping isolation chamber solution.

Claims

1. A plating equipment comprising a plating tank including: an opening part in which an object to be plated is placed; a solution supply piping that supplies a plating solution toward the object to be plated; an insoluble anode that is arranged so as to be opposed to the object to be plated; and an diaphragm for to separate the object to be plated and the insoluble anode from each other, an diaphragm outer peripheral end being fixed to a plating tank inner wall, a through-hole being provided in an diaphragm center, a hole peripheral end of the through-hole being fixed to the solution supply piping, the diaphragm being thus arranged so as to be inclined upward in an outer circumferential direction from the solution supply piping, wherein a silicon ring is firmly fixed to each of the outer peripheral end of the diaphragm and a hole edge of the through-hole of the diaphragm, the solution supply piping supplies the plating solution to an upper catholyte chamber in the plating tank, the upper catholyte chamber being formed by the diaphragm and the placed object to be plated, and an annular flow passage including a solution ejection hole in an upper part thereof is provided in an outer circumference of the solution supply piping, a lower anolyte chamber solution is supplied from the solution ejection hole to a lower anolyte chamber in the plating tank, the lower anolyte chamber being formed below the diaphragm, and a flow that moves from around the through-hole of the diaphragm toward the outer circumferential direction of the diaphragm is thus formed in the lower anolyte chamber solution.

2. The plating equipment according to claim 1, wherein the lower anolyte chamber solution is supplied toward a circumferential direction of the annular flow passage.

3. The plating equipment according to claim 1, comprising a flow rate controller that controls a supply flow rate of the lower anolyte chamber solution supplied to the lower anolyte chamber.

4. The plating equipment according to claim 2, comprising a flow rate controller that controls a supply flow rate of the lower anolyte chamber solution supplied to the lower anolyte chamber.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG. 1 is a cross-sectional view of a plating equipment of a present embodiment;

[0019] FIG. 2 is a plan view of the plating equipment of the present embodiment;

[0020] FIG. 3 is a cross-sectional view of the plating equipment taken along A-A;

[0021] FIG. 4 is a plan view of a diaphragm;

[0022] FIG. 5 illustrates a simultaneous casting process; and

[0023] FIG. 6 is a line graph obtained as a result of examining a concentration change in each additive.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0024] An embodiment of the present invention is described with reference to the drawings. FIG. 1 is a cross-sectional view of a plating equipment of the present embodiment, and FIG. 2 is a plan view of the plating equipment.

[0025] In the plating equipment of the present embodiment, a torus-shape diaphragm 2 having a through-hole in the center thereof is set in a plating tank 1. This diaphragm 2 has a diaphragm outer peripheral end fixed to a plating tank inner wall, and a hole edge of the through-hole is fixed to a leading end of a solution supply piping 3, whereby the diaphragm 2 is inclined upward in the outer circumferential direction from the solution supply piping 3 (in the plan view of FIG. 2, illustration of the diaphragm is omitted). An annular flow passage 4 is provided in an outer circumference of the solution supply piping 3. Moreover, a mesh-like insoluble anode 5 is arranged in a bottom part of the plating tank 1 (in the plan view of FIG. 2, illustration of the insoluble anode is omitted).

[0026] When a wafer W as was an object to be plated is placed in an opening part of the plating tank 1, an upper catholyte chamber U and a lower anolyte chamber D are formed in the plating tank 1. A plating solution is supplied to the upper catholyte chamber U from the solution supply piping 3. Then, a lower anolyte chamber solution is supplied to the lower anolyte chamber D from a solution ejection hole 6 provided to an upper part of the annular flow passage 4.

[0027] FIG. 3 is a cross-sectional view taken along a line A-A in FIG. 2. The solution supply to the annular flow passage 4 is performed by a lower anolyte chamber solution supply piping 7 provided to the plating tank bottom part, and this lower anolyte chamber solution supply piping 7 is configured to enable the solution supply toward the circumferential direction of the annular flow passage 4. The lower anolyte chamber solution that has been supplied from the lower anolyte chamber solution supply piping 7 rotates and flows in the annular flow passage 4 to flow in the lower anolyte chamber D from the solution ejection hole 6. The lower anolyte chamber solution that has flowed in the lower anolyte chamber D forms a flow that spreads in an outer circumference of the diaphragm 2 along a lower surface of the diaphragm 2.

[0028] The plating solution that has been supplied to the upper catholyte chamber D is guided to and discharged from a solution discharge outlet 8 provided to the plating tank 1, and the lower anolyte chamber solution that has been supplied to the lower anolyte chamber D is guided to and discharged from a solution discharge outlet 9 provided to the plating tank 1.

[0029] FIG. 4 is a plan view of the diaphragm 2. A silicon ring 10 is firmly fixed to each of an outer peripheral end 2 of the diaphragm 2 and a hole edge of a through-hole 2. This silicon ring 10 is firmly fixed through a simultaneous casting process of the silicon ring. As an example, description is given here of the case where the silicon ring is firmly fixed to the outer peripheral end of the diaphragm, and FIG. 5 is a cross-sectional view concerning the simultaneous casting process in this case. An upper mold 21 and a lower mold 22 are arranged in the outer peripheral end of the diaphragm 2, and the upper mold 21 and the lower mold 22 are configured to be capable of sandwiching therebetween an end part of the outer peripheral end of the diaphragm 2 along the outer peripheral end thereof, whereby the diaphragm 2 is fixed. The upper mold 21 and the lower mold 22 are processed such that a ring formation space 23 is formed in the outer peripheral end of the diaphragm 2 when the upper mold 21 and the lower mold 22 sandwich the diaphragm 2 therebetween. An injection passage 24 for injecting silicon resin into the ring formation space 23 is formed in the upper mold 21. The diaphragm to which the silicon ring was firmly fixed as illustrated in FIG. 4 was manufactured with the use of such a mold frame as described above.

[0030] Next, description is given of test results obtained as a result of performing a copper plating process with a copper sulfate plating solution by the plating equipment of the present embodiment and examining an additive concentration change in the plating solution.

[0031] This test was carried out in the following manner: a copper sulfate plating solution containing three types of additives (commercial products) called an accelerator (promotor), a suppressor (inhibitor), and a leveler (smoother) was supplied to the upper catholyte chamber corresponding to a cathode side and a copper sulfate plating solution containing no additive was supplied to the lower anolyte chamber corresponding to an anode side. The solution compositions are shown below.

[0032] Upper Catholyte Chamber Supply Solution: [0033] Copper sulfate plating solution (commercial product Microfab Cu525/produced by Electroplating Engineers of Japan Ltd.) [0034] Copper concentration . . . 60 g/L [0035] Sulfuric acid concentration . . . 30 g/L [0036] Accelerator (promotor) . . . 3 mL/L [0037] Suppressor (inhibitor) . . . 10 mL/L [0038] Leveler (smoother) . . . 10 mL/L [0039] Solution temperature 22 to 23 C. [0040] Solution volume 40 L [0041] Supply flow rate 25 L/min

[0042] Lower Anolyte Chamber Supply Solution: [0043] Copper sulfate plating solution (commercial product Microfab Cu525/produced by Electroplating Engineers of Japan Ltd., which is the same solution as that for the upper catholyte chamber) [0044] Solution temperature 22 to 25 C. [0045] Solution volume 20 L [0046] Supply flow rate 5 L/min

[0047] In the plating equipment, a mesh-like insoluble anode made of PtTi was used, and a commercial product (film material: a fluorine-based resin, thickness: 0.12 mm, water permeability: 0.08 mL/min/cm.sup.2 25 C.) was used as the diaphragm. An 8-inch wafer made of PCB was used as the object to be plated. This wafer made of PCB is a object to be plated that is a glass epoxy base material to which copper foil is attached and which is processed into a wafer-like circular shape.

[0048] A testing method included performing a 3 A and 7-hour copper plating process on the wafer made of PCB as the object to be plated collecting the upper catholyte chamber supply solution and the lower anolyte chamber supply solution immediately after the plating and analyzing the concentrations of copper, sulfuric acid, additives, and the like. The upper catholyte chamber supply solution was collected after the upper catholyte chamber supply solution immediately after the plating was replenished with the same amount of copper as that of copper consumed in the copper plating process. After the plating process, a process pause was taken for a predetermined period of time (16 hours). This process pause for the predetermined period of time and the copper plating process were repeated 5 times, and concentration changes in copper, sulfuric acid, the additives, and the like were examined. Moreover, in order to examine time degradation in the solution, after the fifth plating process, a process pause was taken for 48 hours. Then, without the plating process, concentration changes in copper, sulfuric acid, the additives, and the like were examined (sixth time). The obtained results are illustrated in FIG. 6. Note that, during each process pause, the supply amount of the upper catholyte chamber supply solution was 8 to 10 L/min, and the supply amount of the upper catholyte chamber supply solution was 1 to 2 L/min.

[0049] FIG. 6 illustrates a concentration change in each additive in each of the upper catholyte chamber supply solution and the lower anolyte chamber supply solution, and FIG. 6 illustrates the concentration change in the order of the accelerator (promotor), the suppressor (inhibitor), and the leveler from the top by means of line graphs. In each line graph, the vertical axis represents an additive concentration (mL/L), the horizontal axis represents a concentration measurement period, data points represented by squares represent the concentration of the upper catholyte chamber supply solution, and data points represented by circles represent the concentration of the lower anolyte chamber supply solution.

[0050] As illustrated in FIG. 6, for the lower anolyte chamber supply solution containing no additive, additive components were not detected even after a lapse of the process pause period. For the upper catholyte chamber supply solution, there was a tendency that each additive gradually decreased with the increasing number of times of the plating processes. Particularly, the decrease in the concentration of the leveler was large, but the rate of decrease in this result was significantly smaller than the rate of decrease in the case where a soluble anode was used. Moreover, for the copper concentration and the sulfuric acid concentration, almost no concentration change was found in both the upper catholyte chamber supply solution and the lower anolyte chamber supply solution.

[0051] These test results proved that, in the plating equipment of the present embodiment, the upper catholyte chamber supply solution and the lower anolyte chamber supply solution were controlled in the state where the two supply solutions were completely separated from each other by the diaphragm. These test results proved that the additives could be easily managed in the upper catholyte chamber supply solution, and also proved that the consumption amount of such an additive as the leveler whose consumption amount was large could be decreased in the case where a soluble anode was used. Further, because the solution supply amount during the process pause was controlled, deformation of the arranged diaphragm was not seen.

REFERENCE SIGNS LIST

[0052] 1 plating tank [0053] 2 diaphragm [0054] 3 solution supply piping [0055] 4 annular flow passage [0056] 5 insoluble anode [0057] 6 solution ejection hole [0058] 7 lower anolyte chamber solution supply piping [0059] 8 solution discharge outlet [0060] 9 solution discharge outlet [0061] 10 silicon ring [0062] 21 upper mold [0063] 22 lower mold [0064] 23 ring formation space [0065] 24 injection passage [0066] U upper catholyte chamber [0067] D lower anolyte chamber [0068] W wafer