Gradient dragout system in a continuous plating line

• US 6,443,167 B1
• Filed: 09/27/2000
• Issued: 09/03/2002
• Est. Priority Date: 10/05/1999
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Moehle, Paul R., Drew, David M., Hegazi, Eiman A.
• Primary Examiner(s): Gulakowski, Randy
• Assistant Examiner(s): PERRIN, JOSEPH L
• Application Number:
  US09/671,485
• Time in Patent Office: 706 Days
• Field of Search: 68/27, 134/56.R, 134/58.R, 134/60, 134/105, 134/109, 134/201, 134/10, 134/34, 205/100, 205/101
• US Class Current: 134/56.00R
• CPC Class Codes: B01B 1/00 Boiling; Boiling apparatus for physical or chemical purposes ; Evaporation in general
• CPC Class Codes: B01B 1/005 Evaporation for physical or chemical purposes; Evaporation apparatus therefor, e.g. evaporation of liquids for gas phase reactions
• CPC Class Codes: C25D 21/18 of electrolytes C25D21/22 takes precedence
• CPC Class Codes: C25D 21/20 of rinse-solutions C25D21/22 takes precedence

Abstract

An enhanced gradient dragout system conserves plating chemicals, including precious metals by providing a series of tanks with cascading rinse solutions having a flow rate controlled by heating the first tank to increase the evaporation rate. A portion of the concentrated solution in the heated tank is returned to the process tank. The system minimizes the requirements for clean rinse water, and the need for emptying contaminated rinse tanks with associated recovery and disposal environmental and cost issues. The low cost system is flexible and the process is adapted to the material and process requirements of the plating line.

Claims

1. An improved chemical dragout rinse system following a chemical process bath in a plating line including;

a series of rinse tanks having an automatic level probe in the first tank in said series of rinse tanks,

a heater in the first tank in said series of rinse tanks,

a clean water source for supplying the final tank in said series of rinse tanks, and

a means for passing solution from the final tank into the previous tank, and each of the other tanks feeds the previous tank to maintain a constant solution level in each tank.

2. A system as in claim 1 further including a connection mechanism between the first tank in said rinse series and a preceding chemical process bath.

3. A system as in claim 1 including means for controlling the temperature of the first rinse tank is responsive to the temperature of the preceding chemical process bath.

4. A system as in claim 1 wherein five rinse tanks are included in said series of rinse tanks.

5. A system as in claim 1 wherein the solution in one of said rinse tanks has a higher evaporation rate than the others.