Dual stress memory technique method and related structure
First Claim
1. A method of providing a dual stress memory technique in a semiconductor device including an nFET and a pFET, the method comprising:
- forming a first stress layer over the nFET and the pFET, wherein the first stress layer is an intrinsically compressive stressed layerforming an etch stop layer over the first stress layer;
removing the first stress layer and the etch stop layer over the nFETforming a second stress layer over a remaining portion of the first stress layer and the nFET, wherein the second stress layer is a tensilely stressed silicon nitride layer;
annealing to memorize stress in the nFET and the pFET, wherein the remaining portion of the first stress layer remains over the pFET during the annealing, and the second stress layer remains over both the nFET and the pFET during the annealing; and
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removing the first and second stress layers and the etch stop layer in their entirety, wherein the memorized stress is retained in the nFET and the pFET after the annealing and the removing of the first and second stress layers.
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Abstract
A method for providing a dual stress memory technique in a semiconductor device including an nFET and a PFET and a related structure are disclosed. One embodiment of the method includes forming a tensile stress layer over the nFET and a compressive stress layer over the pFET, annealing to memorize stress in the semiconductor device and removing the stress layers. The compressive stress layer may include a high stress silicon nitride deposited using a high density plasma (HDP) deposition method. The annealing step may include using a temperature of approximately 400-1200° C. The high stress compressive silicon nitride and/or the anneal temperatures ensure that the compressive stress memorization is retained in the pFET.
112 Citations
13 Claims
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1. A method of providing a dual stress memory technique in a semiconductor device including an nFET and a pFET, the method comprising:
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forming a first stress layer over the nFET and the pFET, wherein the first stress layer is an intrinsically compressive stressed layer forming an etch stop layer over the first stress layer; removing the first stress layer and the etch stop layer over the nFET forming a second stress layer over a remaining portion of the first stress layer and the nFET, wherein the second stress layer is a tensilely stressed silicon nitride layer; annealing to memorize stress in the nFET and the pFET, wherein the remaining portion of the first stress layer remains over the pFET during the annealing, and the second stress layer remains over both the nFET and the pFET during the annealing; and
;removing the first and second stress layers and the etch stop layer in their entirety, wherein the memorized stress is retained in the nFET and the pFET after the annealing and the removing of the first and second stress layers. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method of providing a dual stress memory technique for a semiconductor device including an nFET and a pFET, the method comprising:
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forming a tensile stress layer over only the nFET and forming a compressive stress layer over the pFET and the tensile stress layer overlying the nFET, wherein the compressive stress layer includes silicon nitride; annealing to memorize stress in the nFET and the pFET, wherein the tensile stress layer remains over only the nFET and the compressive stress layer remains over the pFET and the tensile stress layer overlying the nFET during the annealing; and removing the compressive and tensile stress layers in their entirety, wherein the memorized stress is retained in the nFET and the pFET after the annealing and the removing of the compressive and tensile stress layers. - View Dependent Claims (9, 10, 11, 12, 13)
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Specification