# US 7,744,732 B2 · Continuous plating system and method with mask registration

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- Number: US 7,744,732 B2
- Document ID: US7744732B2
- Status: Granted
- Kind: B2
- Application number: 11/278,947
- Filed: 2006-04-06
- Published: 2007-03-01
- Granted: 2010-06-29
- Earliest claimed: 2005-04-06
- Assignees: Leviton Manufacturing Co., Inc.
- Inventors: Darrell W. Zielke
- Web page: https://patentgrep.com/patent/US7744732B2

## CPC

- C25D 5/022: {using masking means}
- C25D 7/0635: {In radial cells}
- C25D 7/0678: {using masks}
- C25D 17/00: Constructional parts, or assemblies thereof, of cells for electrolytic coating
- C25D 17/28: with means for moving the objects individually through the apparatus during treatment
- H10W 70/457: {of metallic layers on leadframes}
- C25D: PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

A continuous plating system with mask registration is disclosed herein that uses drums and rollers with protruding pins which engage with guide holes in a masking belt and a lead frame. Through engagement with the pins the masking belt is keyed to the lead frame as the lead frame passes through a plating solution tank.

## Claims

### Claim 1

A plating system for plating a portion of each of a plurality of serially arranged parts of a lead frame with a plating solution, the system comprising:
a tank for containing the plating solution;
a first masking belt having a first plurality of guide holes;
a second masking belt having a second plurality of guide holes;
a drive wheel comprising a periphery, the drive wheel being rotatable relative to the tank to position a first portion of the periphery outside the plating solution in the tank, and a second portion of the periphery inside the plating solution in the tank;
a first plurality of pins positioned along the periphery of the drive wheel to sequentially engage with the first plurality of guide holes of the first masking belt;
a second plurality of pins laterally spaced apart from the first plurality of pins, the second plurality of pins being positioned along the periphery of the drive wheel to sequentially engage with the second plurality of guide holes of the second masking belt, the first and second masking belts being sized such that when the first plurality of guide holes of the first masking belt are engaged by the first plurality of pins and the second plurality of guide holes of the second masking belt are engaged by the second plurality of pins, a longitudinally extending opening is defined between the first and second masking belts along the second portion of the periphery of the drive wheel, the periphery of the drive wheel comprising a groove configured to receive the lead frame and register the portion of different serially arranged parts of the lead frame with the longitudinally extending opening defined between the first and second masking belts for subsequent passage of the engaged first masking belt, the engaged second masking belt, and the lead frame into the plating solution in the tank to sequentially pass the serially arranged parts through the plating solution in the tank; and
a plurality of tracking rollers, each tracking roller having a periphery and a plurality of pins positioned along the periphery to sequentially engage with the first plurality of guide holes of the first masking belt to maintain alignment of the first masking belt and the second plurality of guide holes of the second masking belt to maintain alignment of the second masking belt.

### Claim 2 (depends on 1)

The system of claim 1 wherein the periphery of the drive wheel is circular.

### Claim 3 (depends on 1)

The system of claim 1 wherein the periphery of the tracking roller is circular.

### Claim 4 (depends on 1)

The system of claim 1 wherein each of the serially arranged parts of the lead frame has a plurality of tines, a portion of each of the tines being the portion of each of the serially arranged parts of a lead frame to be plated with the plating solution.

### Claim 5 (depends on 1)

The system of claim 1, further comprising a sealing belt positioned to cover a portion of a side of the lead frame opposite a side of the lead frame contacting the first and second masking belts.

### Claim 6 (depends on 1)

The system of claim 1 wherein the drive wheel is made from a substantially electrically non-conductive material.

### Claim 7 (depends on 1)

The system of claim 1 wherein the drive wheel is made from an acrylic plastic.

### Claim 8 (depends on 1)

The system of claim 1 further comprising a spring loaded compliance arm positioned to sequentially apply force on serially arranged portions of the first and second masking belts for further engagement of the first masking belt with the first plurality of pins and further engagement of the second masking belt with the second plurality of pins.

### Claim 9 (depends on 1)

The system of claim 1, further comprising a plurality of belt pulleys positioned to apply force to the first and second masking belts.

### Claim 10 (depends on 1)

The system of claim 1 wherein the drive wheel is positioned to sequentially disengage with serially arranged portions of the first masking belt, serially arranged portions of the second masking belt, and serially arranged portions of the lead frame at a location outside the plating solution subsequent to their passing through the plating solution in the tank.

### Claim 11 (depends on 1)

The system of claim 1 further comprising:
a negatively charged cathode drum positioned to sequentially contact the serially arranged parts of the lead frame prior to their receipt inside the groove of the periphery of the drive wheel.

### Claim 12 (depends on 1)

The system of claim 1 further comprising:
a negatively charged cathode drum positioned to contact the serially arranged parts of the lead frame subsequent to their receipt inside the groove of the periphery of the drive wheel.

### Claim 13 (depends on 1)

The system of claim 1, wherein the periphery of the drive wheel is circular and the system further comprises a concentric band positioned in close proximity to the drive wheel.

### Claim 14 (depends on 13)

The system of claim 13 wherein the concentric band has flutes to direct the plating solution in the tank toward the drive wheel.

### Claim 15 (depends on 13)

The system of claim 13 wherein the concentric band is positively charged.

### Claim 16 (depends on 13)

The system of claim 13 wherein the concentric band has a profile inverse to a portion of the drive wheel circumference.

### Claim 17 (depends on 1)

The system of claim 1 wherein pitch spacing of the first plurality of pins, the second plurality of pins, and the pins of the tracking rollers are substantially equal.

### Claim 18

A plating system for plating a portion of each of a plurality of serially arranged parts of a lead frame with a plating solution, the system comprising:
a tank configured to contain the plating solution;
a first masking belt having a first plurality of guide holes;
a second masking belt having a second plurality of guide holes; and
a rotatable wheel positioned partially out of the plating solution within the tank and partially in the plating solution within the tank when the plating solution is contained inside the tank, the wheel comprising a periphery, a first groove extending around the periphery, a first plurality of pins positioned along the periphery to sequentially engage with the first plurality of guide holes of the first masking belt, and a second plurality of pins positioned along the periphery to sequentially engage with the second plurality of guide holes of the second masking belt, the first and second masking belts being laterally spaced apart from one another to define a longitudinally extending opening therebetween, the lead frame being positioned inside the first groove extending around the periphery of the wheel under the first and second masking belts, to sequentially register the portion of different serially arranged parts of the lead frame with the longitudinally extending opening for subsequent sequential passage of the serially arranged parts through the plating solution within the tank.

### Claim 19 (depends on 18)

The system of claim 18 further comprising a plurality of tracking rollers, each tracking roller having a plurality of pins positioned along a periphery of the tracking roller to sequentially engage with the first plurality of guide holes of the first masking belt and the second plurality of guide holes of the second masking belt.

### Claim 20 (depends on 18)

The system of claim 18, wherein the periphery of the wheel includes a second groove, and the system further comprises a sealing belt positioned in the second groove of the wheel between the lead frame and the wheel, the sealing belt covering a portion of a side of the lead frame toward the wheel when the portion of the lead frame is received inside the first groove extending around the periphery of the wheel.

### Claim 21 (depends on 18)

The system of claim 18 further comprising a compliance arm positioned to sequentially apply force on serially arranged portions of the first and second masking belts for further engagement of the first masking belt with the first plurality of pins of the wheel and further engagement of the second masking belt with the second plurality of pins of the wheel.

### Claim 22 (depends on 18)

The system of claim 18 further comprising a plurality of members positioned to apply force to the first and second masking belts.

### Claim 23 (depends on 18)

The system of claim 18 further comprising a negatively charged cathode drum positioned to sequentially contact the serially arranged parts of the lead frame prior to receipt of the lead frame in the first groove extending around the periphery of the wheel.

### Claim 24 (depends on 22)

The system of claim 22 further comprising a negatively charged cathode drum positioned to contact the serially arranged parts of the lead frame subsequent to receipt of the lead frame in the first groove extending around the periphery of the wheel.

### Claim 25 (depends on 18)

The system of claim 18 further comprising a member positioned in the plating solution within the tank and extending along a portion of the periphery of the wheel in proximity to the wheel, the member having flutes to direct the plating solution within the tank toward the wheel.

### Claim 26 (depends on 25)

The system of claim 25 wherein the member is positively charged.

### Claim 27

A plating system for plating a portion of each of a plurality of serially arranged parts of a lead frame with a plating solution, the system comprising:
a tank configured to contain the plating solution;
a pair of laterally spaced apart masking belts defining a longitudinally oriented opening therebetween, each of the pair of masking belts comprising a plurality of guide holes;
a rotatable wheel positioned partially out of the plating solution within the tank and partially in the plating solution within the tank when the tank contains the plating solution, and having a plurality of pins positioned along a periphery of the wheel to sequentially engage with the plurality of guide holes of each of the pair of masking belts, with the lead frame positioned in a groove of the wheel between the periphery of the wheel and the pair of masking belts, to sequentially register the opening defined between the pair of masking belts with the portion of different serially arranged parts of the lead frame for subsequent sequential passage of the serially arranged parts through the plating solution within the tank;
a plurality of tracking rollers each having a plurality of pins positioned along a periphery of the tracking roller to sequentially engage with the plurality of guide holes of each of the pair of masking belts; and
a sealing belt positioned between the lead frame and the wheel to cover a portion of a side of the lead frame toward the wheel when the portion of the lead frame is positioned in the groove of the wheel.

### Claim 28 (depends on 27)

The system of claim 27 further comprising a compliance arm positioned to sequentially apply force on serially arranged portions of the pair of masking belts for further engagement of the pair of masking belts with the pins of the wheel.

### Claim 29 (depends on 27)

The system of claim 27 further comprising a plurality of members positioned to apply force to the pair of masking belts.

### Claim 30 (depends on 27)

The system of claim 27 further comprising a member positioned in the plating solution within the tank and extending along a portion of the periphery of the wheel in proximity to the wheel, the member having flutes to direct the plating solution within the tank toward the wheel.
