Copper anode for semiconductor interconnects
OwnerThomas D. Nielseninventor
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Abstract
A copper anode is described for use in electroplating semiconductor interconnects, where said anode has a preferred grain size or crystallographic orientation and a preferred chemical composition. The microstructure of the anode may be of two types (1) grains smaller than 100 microns in any dimension or (2) large columnar grains aligned perpendicularly to the anode corroding surface. Copper cathodes of not less than 99.99 weight percent of copper are alloyed to achieve an anode with a phosphor content of 0.045 to 0.060 weight percent.
Claims17
A copper anode for the electroplating of a substrate wherein the copper grain size in the anode is less than 100 microns in any dimension.
A copper anode for the electroplating of a substrate wherein the copper grains in the anode are parallel and columnar shaped and oriented so as to be aligned perpendicular to a corroding surface of the anode.
A copper anode for the electroplating of semiconductor interconnects wherein the anode is manufactured from a copper cathode having a purity of at least 99.99% and wherein the final anode has a phosphor content of between 0.045 and 0.060 weight percent.
A method for electroplating copper on a substrate using a copper anode, wherein at least one of the following conditions are satisfied:
- a) the anode has a copper grain size of less than 100 microns;
- b) the copper grains in the anode are oriented so as to be aligned perpendicular to a corroding surface of the anode;
- and
- c) the anode has a phosphor content of between 0.045 and 0.060 weight percent and is formed from a copper cathode comprising at least 99.99% copper.
A method for the electroplating of semiconductor interconnects on a silicon substrate including the steps of:
- immersing the silicon substrate in an electroplating chamber containing an electrolyte solution;
- positioning a copper anode and a cathode in the electroplating chamber;
- mounting the silicon substrate on the cathode;
- and
- providing a current between the anode and cathode to effect the transfer of Cu2+ ions from the anode to a surface of the silicon substrate;
- wherein at least one of the following conditions are satisfied:
- a) the anode has a copper grain size of less than 100 microns;
- and
- b) the copper grains in the anode are oriented so as to be aligned perpendicular to a corroding surface of the anode.
Dependencies are inferred from the claim text.