Method of electroplating a precious metal on a semiconductor device, integrated circuit or the like

A method for electroplating a layer of precious metal or copper on a surface of a semiconductor device, which method comprises

• (a) providing an electrolytic cell comprising a cathode, an anode, a direct current source and an aqueous electrolyte containing a precious metal compound or a copper compound dissolved therein, said cathode comprising a semiconductor device having a surface for receiving a layer of precious metal or copper;
• (b) orienting the semiconductor device surface for receiving a layer of the precious metal or copper in a position normal to a vector representing the acceleration of gravity and facing the anode of the electrolytic cell, the anode being positioned in the direction of the acceleration of gravity with respect to said surface;
• and
• (c) employing an electroplating direct current on the order of about 0.1 milliamp/cm.sup.2 in the electrolytic cell while superimposing an alternating current electromagnetic field on the electroplating current, said direct current being at or below a value at which the current yield for the deposition is 100 percent, and said electromagnetic field being in the range from about 1 to about 100 megahertz, the strength of said electromagnetic field being sufficiently large to enhance the diffusion, mobility or mass transport of electrolyte ions in solution, said electroplating current and said electromagnetic field being employed in the absence of convection in the electrolyte whereby a smooth, evenly distributed layer of the precious metal or copper is formed on the semiconductor device surface.

A method for electroplating a layer of precious metal or copper on a surface of an integrated circuit device, which method comprises:

• (a) providing an electrolytic cell comprising a cathode, an anode, a direct current source and an aqueous electrolyte containing a precious metal compound or a copper compound dissolved therein, said cathode comprising an integrated circuit device having a surface for receiving a layer of precious metal or copper;
• (b) orienting the integrated circuit device surface for receiving a layer of the precious metal or copper in a position normal to a vector representing the acceleration of gravity and facing the anode of the electrolytic cell, the anode being positioned in the direction of the acceleration of gravity with respect to said surface;
• and
• (c) employing an electroplating direct current not greater than about 0.1 milliamp/cm.sup.2 in the electrolytic cell while superimposing an alternating current electromagnetic field in the range of about 10 to about 15 megahertz on the electroplating current, the strength of said electromagnetic field being sufficiently large to enhance the diffusion, mobility or mass transport of electrolyte ions in solution, said electroplating current and said electromagnetic field being employed in the absence of convection in the electrolyte, whereby a smooth, evenly distributed layer of the precious metal or copper is formed on the integrated circuit device surface.

A method for electroplating a layer of precious metal or copper on a surface of an integrated circuit device, which method comprises

• (a) providing an electrolytic cell comprising a cathode, an anode, a direct current source and an aqueous electrolyte containing a precious metal compound or a copper compound dissolved therein, said cathode comprising an integrated circuit device having a surface for receiving a layer of precious metal or copper;
• (b) orienting the integrated circuit device surface for receiving a layer of the precious metal or copper in a position normal to a vector representing the acceleration of gravity and facing the anode of the electrolytic cell, the anode being positioned in the direction of the acceleration of gravity with respect to said surface;
• and
• (c) employing an electroplating direct current on the order of about 0.1 milliamp/cm.sup.2 in the electrolytic cell while superimposing an alternating current electromagnetic field on the electroplating current, said direct current being at a value at which the current yield for the deposition is 100%, and said electromagnetic field being in the range from about 1 to about 100 megahertz, the strength of said electromagnetic field being sufficiently large to enhance the diffusion, mobility or mass transport of electrolyte ions in solution, said electroplating current and said electromagnetic field being employed int he absence of convection in the electrolyte whereby a smooth, evenly distributed layer of the precious metal or copper is formed on the integrated circuit device surface.

A method for electroplating a layer of aluminum on a surface of a workpiece, which method comprises:

• (a) providing an electrolytic cell comprising a cathode, anode, a direct current source and a liquid electrolyte containing an aluminum compound dissolved therein, said cathode comprising a workpiece having a surface for receiving a layer of aluminum;
• (b) orienting the workpiece surface for receiving a layer of the aluminum in a position normal to a vector representing the acceleration of gravity and facing the anode of the electrolytic cell, the anode being positioned in the direction of the acceleration of gravity with respect to said surface;
• and
• (c) employing an electroplating direct current not greater than about 0.1 milliamp/cm.sup.2 in the electrolytic cell while superimposing an alternating current electromagnetic field in the range of from about 1 to about 100 megahertz, the strength of said electromagnetic field being sufficiently large to enhance the diffusion, mobility or mass transport of electrolyte ions in solution, said electroplating current and said electromagnetic field being employed in the absence of convection in the electrolyte, whereby a smooth, evenly distributed layer of the aluminum is formed on the workpiece surface.