Low resistance peripheral local interconnect contacts with selective wet strip of titanium

A method of forming a memory device, comprising:

• forming a first opening in a dielectric material to expose a source/drain region in a silicon substrate at a peripheral circuitry area, the dielectric material overlying a polysilicon plug over a source/drain region in the silicon substrate adjacent a gate stack in a memory cell array area;
• with the polysilicon plug covered by the dielectric material and not exposed, chemical vapor depositing titanium over the dielectric material and into the first opening to form titanium silicide over the silicon substrate;
• removing the titanium material selective to the titanium silicide;
• forming a second opening in the dielectric material at the memory cell array area to expose the polysilicon plug;
• physical vapor depositing titanium over the dielectric material and into the first and second openings over the exposed polysilicon plug and the titanium silicide and sidewalls of the openings;
• depositing a metal nitride over the titanium;
• and
• depositing a conductive metal over the metal nitride to fill the openings.

A method of forming a memory device, comprising:

• forming a first opening in a dielectric material to expose a source/drain region in a silicon substrate at a peripheral circuitry area, the dielectric material overlying a polysilicon plug over a source/drain region in the silicon substrate adjacent a gate stack in a memory cell array area;
• with the dielectric material overlying the polysilicon plug and said plug not exposed, chemical vapor depositing titanium over the dielectric material and into the first opening to form titanium silicide over the silicon substrate;
• applying a sulfuric acid solution to remove the titanium selective to the titanium silicide;
• forming a second opening in the dielectric material at the memory cell array area to expose the polysilicon plug;
• depositing titanium over the dielectric material and into the first and second openings over the exposed polysilicon plug and the titanium silicide and sidewalls of the openings by physical vapor depositing the titanium;
• physical vapor depositing metal nitride over the titanium;
• and
• chemical vapor depositing a conductive metal over the metal nitride to fill the openings.

A method of forming a memory device, comprising:

• forming a first opening in first and second dielectric layers to expose an active area in a silicon substrate at a peripheral circuitry area, the first dielectric layer overlying the peripheral circuitry area and the second dielectric layer overlying the first dielectric layer and a polysilicon plug over a source/drain region in the silicon substrate adjacent a gate stack in a memory cell array area;
• with the second dielectric layer overlying the polysilicon plug and said plug not exposed, chemical vapor depositing titanium over the second dielectric layer and into the first opening to form titanium silicide over the silicon substrate;
• removing the titanium selective to the titanium silicide;
• forming a second opening in the second dielectric layer at the memory cell array area to expose the polysilicon plug;
• and
• forming metal contacts within the first and second openings to the active area and the exposed polysilicon plug.

A method of forming a memory device, comprising:

• forming a first opening in first and second dielectric layers to expose an active area in a silicon substrate at a peripheral circuitry area, the first dielectric layer overlying the peripheral circuitry area and the second dielectric layer overlying the first dielectric layer and a polysilicon plug over a source/drain region in the silicon substrate adjacent a gate stack in a memory cell array area;
• with the second dielectric layer overlying the polysilicon plug and said plug not exposed, chemical vapor depositing titanium over the second dielectric layer and into the first opening to form titanium silicide over the silicon substrate;
• removing the titanium selective to the titanium silicide;
• forming a second opening in the second dielectric layer at the memory cell array area to expose the polysilicon plug;
• and
• forming metal contacts within the first and second openings to the active area and the exposed polysilicon plug including physical vapor depositing titanium over the second dielectric layer and into the first and second openings over the exposed polysilicon plug and the titanium silicide and sidewalls of the openings.

A method of forming a memory device, comprising:

• forming a first opening in first and second dielectric layers to expose an active area in a silicon substrate at a peripheral circuitry area, the first dielectric layer overlying the peripheral circuitry area and the second dielectric layer overlying the first dielectric layer and a memory cell array area comprising a polysilicon plug over a source/drain region in the silicon substrate adjacent a gate stack;
• with the second dielectric layer overlying the polysilicon plug and said plug not exposed, chemical vapor depositing titanium over the second dielectric layer and into the first opening to form titanium silicide over the silicon substrate;
• removing the titanium selective to the titanium silicide;
• forming a second opening in the second dielectric layer at the memory cell array area to expose the polysilicon plug;
• and
• forming metal contacts within the first and second openings to the active area and the exposed polysilicon plug including physical vapor depositing titanium in the presence of nitrogen over the second dielectric layer and into the first and second openings over the exposed polysilicon plug and the titanium silicide and sidewalls of the openings.

A method of forming a memory device, comprising:

• forming a first opening in first and second dielectric layers to expose an active area in a silicon substrate at a peripheral circuitry area, the first dielectric layer overlying the peripheral circuitry area and the second dielectric layer overlying the first dielectric layer and a memory cell array area comprising a polysilicon plug over a source/drain region in the silicon substrate adjacent a gate stack;
• with the second dielectric layer overlying the polysilicon plug and said plug not exposed, chemical vapor depositing titanium over the second dielectric layer and into the first opening to form titanium silicide over the silicon substrate;
• removing the titanium selective to the titanium silicide;
• forming a second opening in the second dielectric layer at the memory cell array area to expose the polysilicon plug;
• and
• forming metal contacts within the first and second openings to the active area and the exposed polysilicon plug including chemical vapor depositing titanium in the presence of nitrogen over the second dielectric layer and into the first and second openings over the exposed polysilicon plug and the titanium silicide and sidewalls of the openings.

A method of forming a memory device, comprising:

• forming a first opening in a dielectric material to expose an active area in a silicon substrate at a peripheral circuitry area, the dielectric material overlying the peripheral circuitry area and a memory cell array area comprising a polysilicon plug over a source/drain region in the silicon substrate adjacent a gate stack;
• with the dielectric material overlying the polysilicon plug and said plug not exposed, chemical vapor depositing titanium over the dielectric material and into the first opening to form titanium silicide over the silicon substrate;
• removing the titanium selective to the titanium silicide;
• forming a second opening in the dielectric material at the memory cell array area to expose the polysilicon plug;
• and
• forming metal contacts within the first and second openings to the active area and the exposed polysilicon plug.

A method of forming a memory device, comprising:

• forming a first opening in a dielectric material to expose an active area in a silicon substrate at a peripheral circuitry area, the dielectric material overlying the peripheral circuitry area and a memory cell array area comprising a polysilicon plug over a source/drain region in the silicon substrate adjacent a gate stack;
• with the dielectric material overlying the polysilicon plug and said plug not exposed, chemical vapor depositing titanium over the dielectric material and into the first opening to form titanium silicide over the silicon substrate;
• removing the titanium selective to the titanium silicide;
• forming a second opening in the dielectric material at the memory cell array area to expose the polysilicon plug;
• and
• forming metal contacts within the first and second openings to the active area and the exposed polysilicon plug, including physical vapor depositing titanium, optionally in the presence of nitrogen, to form titanium over the dielectric material and into the first and second openings over the exposed polysilicon plug and the titanium silicide and sidewalls of the openings.

A method of forming a memory device, comprising:

• forming a first opening in a dielectric material to expose an active area in a silicon substrate at a peripheral circuitry area, the dielectric material overlying the peripheral circuitry area and a memory cell array area comprising a polysilicon plug over a source/drain region in the silicon substrate adjacent a gate stack;
• with the polysilicon plug covered by the dielectric material and not exposed, chemical vapor depositing titanium over the dielectric material and into the first opening to form titanium silicide over the silicon substrate;
• removing the titanium selective to the titanium silicide;
• forming a second opening in the dielectric material at the memory cell array area to expose the polysilicon plug;
• and
• forming metal contacts within the first and second openings to the active area and the exposed polysilicon plug, including forming titanium over the dielectric material and into the first and second openings over the exposed polysilicon plug and the titanium silicide and sidewalls of the openings by physical vapor deposition of titanium.

A method of forming a memory device, comprising:

• forming a first and second opening in a dielectric material to expose a source/drain in a silicon substrate and a tungsten material of a wordline at a peripheral circuitry area, the dielectric material overlying the peripheral circuitry area and a memory cell array area comprising a polysilicon plug over a source/drain region in the silicon substrate adjacent a gate stack;
• with the dielectric:
• material overlying the polysilicon plug and said plug not exposed, chemical vapor depositing titanium over the dielectric material and into the first and second openings over the exposed source/drain and the tungsten material to form titanium silicide over the silicon substrate;
• removing the titanium selective to the titanium silicide and the tungsten material;
• forming a third opening in the dielectric material at the memory cell array area to expose the polysilicon plug;
• and
• forming metal contacts within the openings to the source/drain region and the tungsten material of the wordline at the peripheral circuitry area, and the exposed polysilicon plug at the memory cell array area.

A semiconductor processing method of forming integrated circuitry, comprising:

• forming memory circuitry and peripheral circuitry over a substrate, the memory circuitry comprising at least one wordline with an adjacent source/drain region in a silicon substrate and a polysilicon plug over the source/drain region adjacent a gate stack, and the peripheral circuitry comprising an active area in the silicon substrate and an overlying first dielectric layer;
• depositing a second dielectric layer over the first dielectric layer and the memory circuitry;
• forming a first opening in the first and second dielectric layers at the peripheral circuitry area to expose the active area in the silicon substrate but not the polysilicon plug;
• with the second dielectric layer overlying the polysilicon plug and said plug not exposed, chemical vapor depositing titanium over the second dielectric layer and into the first opening to form titanium silicide over the silicon substrate;
• removing the titanium selective to the titanium silicide;
• forming a second opening in the second dielectric layer at the memory circuitry to expose the polysilicon plug;
• and
• forming metal contacts within the first and second openings to the active area and the exposed polysilicon plug, including physical vapor depositing titanium over the dielectric layers and into the first and second openings over the exposed polysilicon plug and the titanium silicide and sidewalls of the openings.

A method of forming DRAM integrated circuitry, comprising:

• forming a first opening in a dielectric material to expose a source/drain in a silicon substrate at a DRAM peripheral area, the dielectric material overlying the DRAM peripheral area and a DRAM memory cell array area, each of the peripheral area and the memory cell array area comprising at least one DRAM wordline with an adjacent source/drain region in a silicon substrate, and the memory cell array further comprising a polysilicon plug over the source/drain region adjacent the DRAM wordline;
• with the dielectric material overlying the polysilicon plug and said plug not exposed, chemical vapor depositing titanium over the dielectric material and into the first opening to form titanium silicide over the silicon substrate;
• removing the titanium selective to the titanium silicide;
• forming a second opening in the dielectric material at the memory cell array area to expose the polysilicon plug;
• and
• simultaneously forming metal contacts within the first and second openings to the active area and the exposed polysilicon plug, including physical vapor depositing titanium over the dielectric material and into the first and second openings over the exposed polysilicon plug and the titanium silicide and sidewalls of the openings.

A method of forming DRAM integrated circuitry, comprising:

• forming a first opening in first and second dielectric layers to expose a source/drain in a silicon substrate at a DRAM peripheral area, the first dielectric layer overlying the DRAM peripheral area and the second dielectric layer overlying the first dielectric layer and a DRAM memory cell array area, each of the peripheral area and the memory cell array area comprising at least one DRAM wordline with an adjacent source/drain region in a silicon substrate, and the memory cell array further comprising a polysilicon plug over the source/drain region adjacent the DRAM wordline;
• with the second dielectric, layer overlying the polysilicon plug and said plug not exposed, chemical vapor depositing titanium over the second dielectric layer and into the first opening to form a titanium silicide over the silicon substrate;
• removing the titanium selective to the titanium silicide;
• forming a second opening in the second dielectric layer at the memory cell array area to expose the polysilicon plug;
• and
• forming a DRAM bit line in electrical connection with the polysilicon plug in the memory array area and the source/drain region in the peripheral area by physical vapor depositing titanium, optionally in the presence of nitrogen, over the second dielectric layer into the first and second openings over the exposed polysilicon plug and the titanium silicide and sidewalls of the openings, and depositing a conductive material over the titanium to fill the openings and form conductive contacts.

A method of forming a metallized contact to an active area in a silicon substrate in a peripheral area and a metallized contact to a polysilicon plug in a memory cell array area, comprising:

• etching through an insulating material to form a contact opening to expose the active area of the peripheral area, wherein the polysilicon plug is covered by said insulating material;
• with the insulating material overlying the polysilicon plug and said plug not exposed, chemical vapor depositing titanium over the substrate and into the first opening to form titanium silicide over the silicon substrate;
• applying a sulfuric acid solution to the substrate to remove the titanium selective to the titanium silicide;
• etching through the insulating layer to form a bit line opening to expose a polysilicon plug in the memory cell array area;
• physical vapor depositing titanium over the substrate into the contact opening over the titanium silicide and into the bit line opening over the exposed polysilicon plug, and over the sidewalls of the openings;
• and
• depositing a metal over the titanium to form the metalized contacts in the contact opening at the peripheral area and the bit line opening at the memory cell array area.