Forming gates with varying length using sidewall image transfer
AssigneeInternational Business Machines Corporation
InventorsKangguo Cheng, Juntao Li, Geng Wang, Qintao Zhang
Life of this patent
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Abstract
Semiconductor devices and methods of forming the same include forming mandrels on a first region and a second region of a gate layer. First spacers are formed on sidewalls of the mandrels. The mandrels are etched away to expose inner sidewalls of the first spacers. Second spacers are formed on sidewalls of the first spacers. First spacers in only the first region are etched away to expose inner sidewalls of the second spacers in the first region. The gate layer is etched using the remaining first spacers and the second spacers as a mask to form first gates in the first region and second gates in the second region. The first gates have a gate length than the second gates.
Claims20
A method for forming semiconductor devices, comprising:
- forming mandrels on a first region and a second region of a gate layer;
- forming first spacers on sidewalls of the mandrels;
- etching away the mandrels to expose inner sidewalls of the first spacers;
- forming second spacers on sidewalls of the first spacers;
- etching away first spacers in only the first region to expose inner sidewalls of the second spacers in the first region;
- and
- etching the gate layer using the remaining first spacers and the second spacers as a mask to form first gates in the first region and second gates in the second region, wherein the first gates have a smaller gate length than a gate length of the second gates.
A method for forming semiconductor devices, comprising:
- forming mandrels on a first region and a second region of a gate layer;
- forming first spacers on sidewalls of the mandrels;
- etching away the mandrels to expose inner sidewalls of the first spacers;
- forming second spacers on sidewalls of the first spacers at a thickness that provides a gap between adjacent second spacers that has a same length as a thickness of the first spacers;
- masking the second region;
- etching away first spacers in only the first region to expose inner sidewalls of the second spacers in the first region;
- unmasking the second region after etching away first spacers;
- and
- etching the gate layer using the remaining first spacers and the second spacers as a mask to form first gates in the first region and second gates in the second region, wherein the first gates have a gate length greater than a gate length of the second gates.
A method for forming semiconductor devices, comprising:
- forming amorphous silicon mandrels on a first region and a second region of a gate layer;
- forming amorphous carbon first spacers on sidewalls of the mandrels;
- etching away the mandrels to expose inner sidewalls of the first spacers;
- forming oxide second spacers on sidewalls of the first spacers at a thickness that provides a gap between adjacent second spacers that has a same length as a thickness of the first spacers;
- masking the second region;
- etching away first spacers in only the first region to expose inner sidewalls of the second spacers in the first region;
- unmasking the second region after etching away first spacers;
- and
- etching the gate layer using the remaining first spacers and the second spacers as a mask to form first gates in the first region and second gates in the second region, wherein the first gates have a gate length greater than a gate length of the second gates.
Dependencies are inferred from the claim text.