Removal of wafer edge defocus due to CMP

A process for chemical mechanical polishing of a semiconductor wafer whose upper surface has a central region and a peripheral region, comprising:

• providing a first chemical mechanical polishing apparatus that further comprises a standard retaining ring, a first membrane supporting said wafer, and a hard polishing pad, whereby, after polishing with said first apparatus, said peripheral region is between about 1,000 and 2,000 Angstroms below said central region;
• providing a second chemical mechanical polishing apparatus that further comprises a slotted retaining ring, a second membrane supporting said wafer, and a hard polishing pad, whereby, after polishing with said second apparatus, said peripheral region is between about 1,000 and 2,000 Angstroms above said central region;
• depositing a plurality of layers onto said wafer;
• and
• planarizing each layer prior to the deposition of the next layer, using one of said chemical mechanical apparatuses, whereby no two contiguous layers are planarized using the same apparatus.

A process for chemical mechanical polishing of a semiconductor wafer whose upper surface has a central region and a peripheral region, comprising:

• providing a first chemical mechanical polishing apparatus that further comprises a standard retaining ring, a first membrane supporting said wafer, and a soft polishing pad, whereby, after polishing with said first apparatus, said peripheral region is between about 1,000 and 2,000 Angstroms above said central region;
• providing a second chemical mechanical polishing apparatus that further comprises a slotted retaining ring, a second membrane supporting said wafer, and a soft polishing pad, whereby, after polishing with said second apparatus, said peripheral region is between about 1,000 and 2,000 Angstroms below said central region;
• depositing a plurality of layers onto said wafer;
• and
• planarizing each layer prior to the deposition of the next layer, using one of said chemical mechanical apparatuses, whereby no two contiguous layers are planarized using the same apparatus.

A process for chemical mechanical polishing of a semiconductor wafer whose upper surface has a central region and a peripheral region, comprising:

• providing a first chemical mechanical polishing apparatus that further comprises a standard retaining ring and a first polishing pad, whereby, after polishing with said first apparatus, said peripheral region is between about 1,000 and 2,000 Angstroms below said central region;
• providing a second chemical mechanical polishing apparatus that further comprises a standard retaining ring and a second polishing pad that is softer than said first polishing pad, whereby, after polishing with said second apparatus, said peripheral region is between about 200 and 2,000 Angstroms above said central region;
• depositing a plurality of layers onto said wafer;
• and
• planarizing each layer prior to the deposition of the next layer, using one of said chemical mechanical apparatuses, whereby no two contiguous layers are planarized using the same apparatus.

A process for chemical mechanical polishing of a semiconductor wafer whose upper surface has a central region and a peripheral region, comprising:

• providing a first chemical mechanical polishing apparatus that further comprises a slotted retaining ring and a first polishing pad, whereby, after polishing with said first apparatus, said peripheral region is between about 1,000 and 2,000 Angstroms above said central region;
• providing a second chemical mechanical polishing apparatus that further comprises a slotted retaining ring and a second polishing pad that is softer than said first polishing pad, whereby, after polishing with said second apparatus, said peripheral region is between about 1,000 and 2,000 Angstroms below said central region;
• depositing a plurality of layers onto said wafer;
• and
• planarizing each layer prior to the deposition of the next layer, using one of said chemical mechanical apparatuses, whereby no two contiguous layers are planarized using the same apparatus.