Method of reducing cross contamination during manufacture of copper-contact and gold-contact gaas wafers using shared equipment

Abstract

Systems, apparatuses, and methods related to the design, fabrication, and manufacture of gallium arsenide (GaAs) integrated circuits are disclosed. Copper can be used as the contact material for a GaAs integrated circuit. Metallization of the wafer and through-wafer vias can be achieved through copper plating processes disclosed herein. Various protocols can be employed during processing to avoid cross-contamination between copper-plated and non-copper-plated wafers. GaAs integrated circuits can be singulated, packaged, and incorporated into various electronic devices.

1 . A method of reducing cross contamination during the manufacture of copper-contact and gold-contact GaAs wafers using shared equipment, the method comprising:
 marking copper-contact wafers using a first marker;   marking gold-contact wafers using a second marker;   preparing the gold-contact wafers and the copper-contact wafers for respective gold and copper plating using the same equipment;   performing copper plating of the copper-contact wafers using a first piece of equipment solely dedicated to copper plating;   performing gold plating of the gold-contact wafers using a second piece of equipment different from the first piece of equipment; and   following the respective copper plating and gold plating, preparing a plurality of integrated circuits using the same equipment and incorporating at least one of the gold-contact wafers and the copper-contact wafers.   
     
     
         2 . The method of  claim 1  wherein the preparing includes street formation, flash gold coating, debonding, cleaning, singulation, and recast etching of the copper-contact wafers and the gold-contact wafers. 
     
     
         3 . The method of  claim 1  further including fitting personnel with colored gloves based on whether the personnel are handling the gold-contact wafers or the copper-contact wafers. 
     
     
         4 . The method of  claim 1  wherein the performing copper plating includes pre-cleaning the copper-contact wafers, depositing a barrier and/or seed layer onto the copper-contact wafers, copper plating the copper-contact wafers, and heat treating the copper-contact wafers after the copper plating. 
     
     
         5 . The method of  claim 1  wherein the first piece of equipment includes first vacuum wands, first microscopes, first gloves, and first cassettes for the copper-contact wafers. 
     
     
         6 . The method of  claim 5  wherein the second piece of equipment includes second vacuum wands, second microscopes, second gloves, and second cassettes for the gold-contact wafers. 
     
     
         7 . The method of  claim 1  wherein the first marker is a tag with desired lettering. 
     
     
         8 . The method of  claim 7  wherein the desired lettering includes the word copper in a native language of production personnel. 
     
     
         9 . A method of reducing cross contamination during the manufacture of copper-contact and gold-contact GaAs wafers using shared equipment, the method comprising:
 marking copper-contact wafers using a first marker;   preparing the gold-contact wafers and the copper-contact wafers for respective gold and copper plating using the same equipment;   performing copper plating of the copper-contact wafers using a first piece of equipment solely dedicated to copper plating;   performing gold plating of the gold-contact wafers using a second piece of equipment different from the first piece of equipment; and   following the respective copper plating and gold plating, preparing a plurality of integrated circuits using the same equipment and incorporating at least one of the gold-contact wafers and the copper-contact wafers.   
     
     
         10 . The method of  claim 9  wherein the preparing includes street formation, flash gold coating, debonding, cleaning, singulation, and recast etching of the copper-contact wafers and the gold-contact wafers. 
     
     
         11 . The method of  claim 9  further including fitting personnel with colored gloves based on whether the personnel are handling the gold-contact wafers or the copper-contact wafers. 
     
     
         12 . The method of  claim 9  wherein the performing copper plating includes pre-cleaning the copper-contact wafers, depositing a barrier and/or seed layer onto the copper-contact wafers, copper plating the copper-contact wafers, and heat treating the copper-contact wafers after the copper plating. 
     
     
         13 . The method of  claim 9  wherein the first piece of equipment includes first vacuum wands, first microscopes, first gloves, and first cassettes for the copper-contact wafers. 
     
     
         14 . The method of  claim 13  wherein the second piece of equipment includes second vacuum wands, second microscopes, second gloves, and second cassettes for the gold-contact wafers. 
     
     
         15 . The method of  claim 9  wherein the first marker is a tag with desired lettering. 
     
     
         16 . The method of  claim 15  wherein the desired lettering includes the word copper in a native language of production personnel. 
     
     
         17 . A method of reducing cross contamination during the manufacture of copper-contact and gold-contact GaAs wafers using shared equipment, the method comprising:
 marking copper-contact wafers using a first marker;   marking gold-contact wafers using a second marker;   preparing the gold-contact wafers and the copper-contact wafers for respective gold and copper plating using the same equipment;   performing copper plating of the copper-contact wafers using a first piece of equipment solely dedicated to copper plating; and   performing gold plating of the gold-contact wafers using a second piece of equipment different from the first piece of equipment.   
     
     
         18 . The method of  claim 17  wherein the preparing includes street formation, flash gold coating, debonding, cleaning, singulation, and recast etching of the copper-contact wafers and the gold-contact wafers. 
     
     
         19 . The method of  claim 17  further including fitting personnel with colored gloves based on whether the personnel are handling the gold-contact wafers or the copper-contact wafers. 
     
     
         20 . The method of  claim 17  wherein the performing copper plating includes pre-cleaning the copper-contact wafers, depositing a barrier and/or seed layer onto the copper-contact wafers, copper plating the copper-contact wafers, and heat treating the copper-contact wafers after the copper plating.