Mask material conversion
US7910288B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 1, 2004 |
| Grant date | Mar 22, 2011 |
| Priority date | — |
| Expiry date | Feb 3, 2028 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/32139
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
The dimensions of mask patterns, such as pitch-multiplied spacers, are controlled by controlled growth of features in the patterns after they are formed. To form a pattern of pitch-multiplied spacers, a pattern of mandrels is first formed overlying a semiconductor substrate. Spacers are then formed on sidewalls of the mandrels by depositing a blanket layer of material over the mandrels and preferentially removing spacer material from horizontal surfaces. The mandrels are then selectively removed, leaving behind a pattern of freestanding spacers. The spacers comprise a material, such as polysilicon and amorphous silicon, known to increase in size upon being oxidized. The spacers are oxidized to grow them to a desired width. After reaching the desired width, the spacers can be used as a mask to pattern underlying layers and the substrate. Advantageously, because the spacers are grown by oxidation, thinner blanket layers can be deposited over the mandrels, thereby allowing the deposition of more conformal blanket layers and widening the process window for spacer formation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.