Method and system for precisely positioning a waist of a material-processing laser beam to process microstructures within a laser-processing site
US6483071B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | May 16, 2000 |
| Grant date | Nov 19, 2002 |
| Priority date | — |
| Expiry date | May 16, 2020 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB23K2101/40
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A high-speed method and system for precisely positioning a waist of a material-processing laser beam to dynamically compensate for local variations in height of microstructures located on a plurality of objects spaced apart within a laser-processing site are provided. In the preferred embodiment, the microstructures are a plurality of conductive lines formed on a plurality of memory dice of a semiconductor wafer. The system includes a focusing lens subsystem for focusing a laser beam along an optical axis substantially orthogonal to a plane, an x-y stage for moving the wafer in the plane, and a first air bearing sled for moving the focusing lens subsystem along the optical axis. The reference data is generated by the system which includes a modulator for reducing power of the material-processing laser beam to obtain a probe laser beam to measure height of the semiconductor wafer at a plurality of locations about the site to obtain reference height data. A computer computes a reference surface based on the reference height data. A trajectory planner generates trajectories for the wafer and the waist of the laser beam based on the reference surface.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.