Method for forming an improved T-shaped gate structure
First Claim
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1. A method of forming a T-shaped gate structure comprising the steps of:
- providing a semiconductor substrate comprising at least one overlying sacrificial layer;
etching the at least one sacrificial layer to form an opening therein using a separate photoresist layer as an etch mask, said opening having a wider upper portion compared to a bottom portion;
backfilling the opening with a gate electrode material to form a gate structure having a T-shaped, wherein the at least one sacrificial layer comprises a silicon oxide layer on the semiconductor substrate and a nitride layer on the silicon oxide layer; and
removing the at least one sacrificial layer to expose at least one portion of a sidewall of the gate structure after the step of backfilling.
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Abstract
A T-shaped gate structure and method for forming the same the method including providing a semiconductor substrate comprising at least one overlying sacrificial layer; lithographically patterning a resist layer overlying the at least one sacrificial layer for etching an opening; forming the etched opening through a thickness of the at least one sacrificial layer to expose the semiconductor substrate, said etched opening comprising a tapered cross section having a wider upper portion compared to a bottom portion; and, backfilling the etched opening with a gate electrode material to form a gate structure.
33 Citations
20 Claims
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1. A method of forming a T-shaped gate structure comprising the steps of:
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providing a semiconductor substrate comprising at least one overlying sacrificial layer; etching the at least one sacrificial layer to form an opening therein using a separate photoresist layer as an etch mask, said opening having a wider upper portion compared to a bottom portion; backfilling the opening with a gate electrode material to form a gate structure having a T-shaped, wherein the at least one sacrificial layer comprises a silicon oxide layer on the semiconductor substrate and a nitride layer on the silicon oxide layer; and removing the at least one sacrificial layer to expose at least one portion of a sidewall of the gate structure after the step of backfilling. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method of forming a T-shaped gate structure comprising the steps of:
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providing a semiconductor substrate comprising an overlying silicon oxide layer and a nitride layer overlying the silicon oxide layer; lithographically patterning a resist layer overlying the nitride layer to form an opening therein; forming an etched opening to etch through a thickness of the nitride layer using the resist layer with the opening as an etch mask, said etched opening having a wider upper portion compared to a bottom portion; removing the silicon oxide layer to expose the semiconductor substrate; and backfilling the etched opening with a gate dielectric on the semiconductor substrate and a gate electrode material on the gate dielectric to form a gate electrode.
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16. A method of forming a T-shaped gate structure comprising the steps of:
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providing a semiconductor substrate comprising at least one overlying sacrificial layer; etching the at least one sacrificial layer to form an opening therein using a separate photoresist layer as an etch mask, said opening having a wider upper portion compared to a bottom portion, wherein the upper portion of the opening comprises a first sidewall taper angle and a bottom portion of the opening comprises a second sidewall taper angle closer to being vertical compared to the first sidewall taper angle; backfilling the opening with a gate electrode material to form a gate structure having a T-shaped, wherein the at least one sacrificial layer comprises a silicon oxide layer on the semiconductor substrate and a nitride layer on the silicon oxide layer; and removing the at least one sacrificial layer to expose at least one portion of a sidewall of the gate structure after the step of backfilling. - View Dependent Claims (17, 18, 19, 20)
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Specification