Method of manufacturing gaas integrated circuits with alternative backside conductive material

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 manufacturing GaAs integrated circuits with alternative backside conductive material, said method comprising:
 separately marking gold-contact wafers and copper-contact wafers;   pre-bonding testing the gold-contact wafers and the copper-contact wafers using shared equipment and tooling;   bonding the gold-contact wafers to a carrier and the copper-contact wafers to a carrier using shared equipment and tooling;   thinning the gold-contact wafers and the copper-contact wafers using shared equipment and tooling;   stress relieving the gold-contact wafers and the copper-contact wafers using shared equipment and tooling;   forming through-wafer vias in the gold-contact wafers and the copper-contact wafers using shared equipment and tooling;   separating the gold-contact wafers and the copper-contact wafers after forming through-wafer vias; and   copper plating the copper-contact wafers and gold plating the gold-contact wafers using different equipment and tooling after the separating.   
     
     
         2 . The method of  claim 1  wherein the 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. 
     
     
         3 . The method of  claim 1  further including forming streets in the gold-contact wafers and the copper-contact wafers using shared equipment and tooling after the copper plating and the gold plating. 
     
     
         4 . The method of  claim 1  wherein the different equipment and tooling includes different vacuum wands, microscopes, gloves, and cassettes for the copper-contact wafers and the gold-contact wafers. 
     
     
         5 . The method of  claim 1  wherein the separately marking includes adding a tag with desired lettering. 
     
     
         6 . The method of  claim 5  wherein the desired lettering includes the word copper in a native language of production personnel. 
     
     
         7 . The method of  claim 1  wherein the different equipment and tooling includes plating equipment and wafer carriers. 
     
     
         8 . A method of manufacturing GaAs integrated circuits with alternative backside conductive material, said method comprising:
 pre-bonding testing gold-contact wafers and copper-contact wafers using shared equipment and tooling;   bonding the gold-contact wafers to a carrier and the copper-contact wafers to a carrier using shared equipment and tooling;   thinning the gold-contact wafers and the copper-contact wafers using shared equipment and tooling;   stress relieving the gold-contact wafers and the copper-contact wafers using shared equipment and tooling;   forming through-wafer vias in the gold-contact wafers and the copper-contact wafers using shared equipment and tooling;   separating the gold-contact wafers and the copper-contact wafers after forming through-wafer vias; and   copper plating the copper-contact wafers and gold plating the gold-contact wafers using different equipment and tooling after the separating.   
     
     
         9 . The method of  claim 8  wherein the 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. 
     
     
         10 . The method of  claim 8  further including forming streets in the gold-contact wafers and the copper-contact wafers using shared equipment and tooling after the copper plating and the gold plating. 
     
     
         11 . The method of  claim 8  wherein the different equipment and tooling includes different vacuum wands, microscopes, gloves, and cassettes for the copper-contact wafers and the gold-contact wafers. 
     
     
         12 . The method of  claim 8  wherein the gold-contact wafers are marked with a tag having a first lettering and the copper-contact wafers are marked with a tag having a second lettering. 
     
     
         13 . The method of  claim 8  wherein the different equipment and tooling includes plating equipment and wafer carriers. 
     
     
         14 . A method of manufacturing GaAs integrated circuits with alternative backside conductive material, said method comprising:
 separately marking gold-contact wafers and copper-contact wafers;   bonding the gold-contact wafers to a carrier and the copper-contact wafers to a carrier using shared equipment and tooling;   thinning the gold-contact wafers and the copper-contact wafers using shared equipment and tooling;   stress relieving the gold-contact wafers and the copper-contact wafers using shared equipment and tooling;   forming through-wafer vias in the gold-contact wafers and the copper-contact wafers using shared equipment and tooling;   separating the gold-contact wafers and the copper-contact wafers after forming through-wafer vias; and   copper plating the copper-contact wafers and gold plating the gold-contact wafers using different equipment and tooling after the separating.   
     
     
         15 . The method of  claim 14  wherein the 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. 
     
     
         16 . The method of  claim 14  further including forming streets in the gold-contact wafers and the copper-contact wafers using shared equipment and tooling after the copper plating and the gold plating. 
     
     
         17 . The method of  claim 14  wherein the different equipment and tooling includes different vacuum wands, microscopes, gloves, and cassettes for the copper-contact wafers and the gold-contact wafers. 
     
     
         18 . The method of  claim 14  wherein the separately marking includes adding a tag with desired lettering. 
     
     
         19 . The method of  claim 18  wherein the desired lettering includes the word copper in a native language of production personnel. 
     
     
         20 . The method of  claim 14  wherein the different equipment and tooling includes plating equipment and wafer carriers.