Method for monitoring resist charging in a charged particle system
US5838013A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 13, 1996 |
| Grant date | Nov 17, 1998 |
| Priority date | — |
| Expiry date | Nov 13, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2237/31796
- WIPO fieldMicro-structural and nano-technology
- WIPO sectorChemistry
Abstract
A method for monitoring resist charging in an electron beam lithography system is disclosed. The method involves the use of a reference plate (REFP) registration scheme in which a resist-coated REFP having registration marks on a substrate is prepared and scanned. The scanning process includes the deposition of an amount of charge on the surface. Then the REFP is coated with a resist to be tested and scanned again. The difference between the two scans is calculated. Preferably, each scan is performed first with the stage moving in a forward-ordered serpentine path in the tool to determine the perceived positions of the registration marks and then in a backward-ordered serpentine path. As the tool's stage moves from field to field, a small charge is deposited on the REFP to simulate the effect of a writing process. The difference between the forward and reverse scan position measurements is then determined. As any intrinsic positional errors in measurement will cancel out, the forward/backward error provides a monitor of the magnitude of resist charging.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.