Method and apparatus for image alignment in ion lithography
US4967088A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Jun 2, 1988 |
| Grant date | Oct 30, 1990 |
| Priority date | — |
| Expiry date | Jun 2, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2237/31776
- WIPO fieldMicro-structural and nano-technology
- WIPO sectorChemistry
Abstract
In an ion projection lithography system, apparatus and methods for positioning on a substrate or wafer at a target station an image of structures provided on a mask, wherein the mask includes reference marks to provide ion reference beams about the image field, the target station includes marks and the beam of the system is controlled to establish a coincidence of the marks on the mask with the corresponding marks at the target station. The ion projection system shown includes in this optical path an electrostatic multipole, means for rotational adjustment of the image relative to the substrate, and means for correcting the scale of the image. Embodiments are shown in which the marks at the target station are carried on the wafer or on a reference block which is positionally related to the wafer, e.g., by an interferometer. In the case of the reference block, it has an aperture corresponding in size to the mask image to be formed on the substrate so that the marks are disposed outside the optical path used to generate the image on the substrate. Detectors provided for secondary radiation emitted by the marks at the target station as a result of the ion reference beams passing throu…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.