Methods to pattern contacts using chromeless phase shift masks
US7374865B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 25, 2002 |
| Grant date | May 20, 2008 |
| Priority date | — |
| Expiry date | Sep 7, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F1/34
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Method for using chromeless phase shift lithography (CPL) masks to pattern contacts on semiconductor substrates and corresponding CPL masks for performing the method. The method for patterning contacts includes illuminating a CPL mask comprising a reticle having a plurality of phase-shifting features interspersed with non-phase-shifting areas using a short wavelength UV light source, wherein the phase-shifting features are configured in a pattern corresponding to a target pattern of the contacts on the semiconductor substrate. Phase-shifted and non-phase-shifted light passing through the reticle are projected as an aerial image onto a layer of a negative tone resist applied over the semiconductor substrate to pattern the contacts in the resist. The phase-shifting features are recesses which cause light passing therethrough to be phase-shifted by approximately 180° from light passing through non-phase-shifting areas of the mask. Each recess in the CPL mask is used to pattern a separate contact on the semiconductor substrate.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.