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US 6,605,533 B2Granted
Process for forming low resistance metal silicide local interconnects
AssigneeMicron Technology, Inc.
InventorJigish D. Trivedi
Life of this patent
Estimating the term…
Abstract
A process for forming a local interconnect includes applying a layer of metal over a semiconductor layer. A layer of metal silicide is formed over the layer of metal. The layer of metal silicide is patterned to define the boundaries of the local interconnect. The metal silicide is reacted with the layer of metal to form a composite structure. The composite structure includes the metal silicide, another metal silicide formed as silicon from the metal silicide reacts with the underlying layer of metal and an intermetallic compound of the metal from the layer of metal and metal from the layer of metal silicide. The unreacted layer of metal is removed with the composite structure remaining as the local interconnect.
Claims31
A process of forming a local interconnect comprising:
- providing at least one semiconductor layer;
- forming a layer of metal over said at Least one semiconductor layer;
- forming a contact etch stop comprising a metal silicide over said layer of metal;
- reacting said layer of metal with said contact etch stop in a reactive nitrogen atmosphere to form a composite structure comprising an intermetallic compound containing no non-metallic materials;
- and
- removing unreacted metal from said layer of metal to form said local interconnect.
3 more elements
A process of forming a local interconnect comprising:
- providing at least one semiconductor layer;
- forming a layer of metal over said at least one semiconductor layer;
- forming a layer of metal silicide over said layer of metal;
- reacting said layer of metal silicide with said layer of metal in a reactive nitrogen atmosphere to form a composite structure comprising an intermetallic compound containing no non-metallic materials;
- and
- removing unreacted metal remaining from said layer of metal to form said local interconnect.
3 more elements
A process of forming a local interconnect comprising:
- providing at least one semiconductor layer;
- forming a layer of metal over said at least one semiconductor layer by chemical vapor deposition (CVD);
- forming a layer of metal silicide over said layer of metal by CVD, wherein said step of forming a layer of metal over said at least one semiconductor layer by CVD and said step of forming a layer of metal silicide over said layer of metal by CVD are carried out in the same vacuum environment;
- patterning said layer of metal silicide;
- reacting said metal silicide with said layer of metal to form a composite structure comprising an intermetallic compound containing no non-metallic materials;
- and
- removing unreacted metal remaining from said layer of metal to form said local interconnect.
4 more elements
A process of forming a local interconnect comprising:
- providing at least one semiconductor layer;
- forming a layer of metal over said at least one semiconductor layer;
- forming a layer of first metal silicide over said layer of metal;
- annealing said layer of first metal silicide and said layer of metal to form a composite structure, said composite structure comprising said first metal silicide, a second metal silicide and an intermetallic compound comprising metal from said layer of metal and metal from said first metal silicide, wherein said intermetallic compound contains no non-metallic materials;
- and
- removing remaining metal from said layer of metal to form said local interconnect.
3 more elements
A process of forming a local interconnect comprising:
- providing at least one semiconductor layer;
- forming a layer of refractory metal over said at least one semiconductor layer;
- forming a layer of first metal silicide over said layer of refractory metal;
- patterning said layer of first metal silicide to define a boundary of said local interconnect;
- annealing said patterned first metal silicide and said layer of refractory metal to form a composite structure in an atmosphere of reactive nitrogen such that at least remaining refractory metal from said layer of refractory metal is nitrified, wherein said composite structure comprises an intermetallic compound containing no non-metallic materials;
- and
- removing remaining refractory metal from said layer of refractory metal to form said local interconnect.
4 more elements
A process of forming a semiconductor device comprising:
- providing a substrate assembly having at least one semiconductor layer;
- forming source and drain regions of a field effect transistor in said at least one semiconductor layer;
- forming a gate oxide over said at least one semiconductor layer;
- forming a gate contact over said gate oxide;
- forming a layer of refractory metal over said at least one semiconductor layer;
- forming a layer of first metal silicide over said layer of metal;
- patterning said layer of first metal silicide to define a boundary of a local interconnect;
- annealing said layer of refractory metal and said layer of first metal silicide in a reactive nitrogen atmosphere to form a composite structure comprising an intermetallic compound containing no non-metallic materials;
- and
- removing remaining refractory metal from said layer of refractory metal to form said local interconnect.
7 more elements
A process of forming a memory array, said memory array comprising a plurality of memory cells arranged in rows and columns, each of said plurality of memory cells comprising at least one field effect transistor, said process comprising:
- providing at least one semiconductor layer;
- forming sources, drains and gates for each of said field effect transistors over said at least one semiconductor layer;
- forming a layer of refractory metal over said at least one semiconductor layer;
- forming a layer of first metal silicide over said layer of refractory metal;
- patterning said layer of first metal silicide to define a boundary of at least one local interconnect;
- and
- annealing said layer of refractory metal and said layer of first metal silicide in a reactive nitrogen atmosphere to form composite structure, wherein said composite structure comprises an intermetallic compound containing no non-metallic materials.
4 more elements
A process of fabricating a wafer comprising:
- providing a wafer having a substrate assembly, said substrate assembly having at least one semiconductor layer;
- forming a repeating series of sources, drains and gates for at least one field effect transistor on each of a plurality of individual die on said wafer over said at least one semiconductor layer;
- forming a layer of refractory metal over said at least one semiconductor layer;
- forming a layer of first metal silicide over said layer of refractory metal;
- patterning said layer of first metal silicide to define a boundary of at least one local interconnect in each of said individual die;
- annealing said layer of refractory metal and said layer of first metal silicide in a reactive nitrogen atmosphere to form a composite structure comprising an intermetallic compound containing no non-metallic materials;
- and
- removing remaining refractory metal from said layer of refractory metal to form said at least one local interconnect in each of said individual die, said at least one local intex-connect in each of said individual die connecting at least one of said source, drain and gate of one of said field effect transistors with another active area in each of said individual die.
5 more elements
A process of forming a local interconnect comprising:
- providing at least one semiconductor layer;
- forming a layer of titanium over said at least one semiconductor layer;
- forming a layer of tungsten silicide over said layer of titanium;
- reacting said layer of tungsten silicide with said layer of titanium in a nitrogen atmosphere to form a composite structure comprising a titanium tungsten intermetallic compound;
- and
- removing unreacted metal remaining from said layer of titanium to from said local interconnect.
3 more elements
A process of forming a local interconnect comprising:
- providing at least one semiconductor layer;
- forming a layer of titanium over said at least one semiconductor layer;
- forming a layer of tungsten silicide over said layer of titanium;
- annealing said layer of tungsten silicide and said layer of titanium thereby forming composite structure wherein said composite structure comprises said tungsten silicide, a titanium silicide and a titanium tungsten intermetallic compound, wherein said intermetallic compound contains no non-metallic materials;
- and
- removing remaining metal from said layer of titanium to form said local interconnect.
3 more elements
A process of forming a local interconnect comprising:
- providing at least one semiconductor layer;
- forming a layer of titanium over said at least one semiconductor layer;
- forming a mask layer of tungsten silicide over said layer of titanium;
- selectively etching said mask layer to define a boundary of said local interconnect;
- annealing said mask layer and said layer of titanium in an atmosphere of reactive nitrogen thereby forming a composite structure where said mask layer contacts said layer of titanium and nitrifying at least said layer of titanium not covered by said mask layer to form a layer of titanium nitride, said composite structure comprising titanium silicide, tungsten silicide and a titanium tungsten intermetallic compound, wherein said intermetallic compound contains no non-metallic materials;
- and
- removing said layer of titanium nitride and underlying titanium to form said local interconnect.
4 more elements
A process of forming a local interconnect comprising:
- providing at least one semiconductor layer;
- forming a layer of refractory metal over said at least one semiconductor layer;
- forming a layer of first metal silicide over said layer of refractory metal;
- patterning said layer of first metal silicide to define a boundary of said local interconnect;
- selectively etching said layer of first metal silicide;
- dry etching said layer of first metal silicide;
- annealing said patterned first metal silicide and said layer of refractory metal to form a composite structure in an atmosphere of reactive nitrogen such that at least remaining refractory metal from said layer of refractory metal is nitrified, wherein said composite structure comprises an intermetallic compound containing no non-metallic materials;
- and
- removing remaining refractory metal from said layer of refractory metal to from said local interconnect.
6 more elements
A process of forming a local interconnect comprising:
- providing at least one semiconductor layer;
- forming a layer of metal over said at least one semiconductor layer;
- forming a layer of first metal silicide over said layer of metal;
- annealing said layer of first metal silicide and said layer of metal to form a composite structure, wherein said composite stricture comprising said first metal silicide, a second metal silicide, and an intermetallic compound consisting of metal from said layer of metal and metal from said first metal silicide, wherein said intermetallic compound contains no non-metallic materials;
- and
- removing remaining metal from said layer of metal to form said local interconnect.
3 more elements
Dependencies are inferred from the claim text.