Intense laser irradiation using reflective optics
US4749840A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 16, 1986 |
| Grant date | Jun 7, 1988 |
| Priority date | — |
| Expiry date | May 16, 2006 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB23K2101/40
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
Intense far-ultraviolet laser radiation is applied to a workpiece in performance of processes in the fabrication of integrated circuits, including processes of ablation, deposition, impurity implantation and radiation induced chemical processes. Other processes where intense far-ultraviolet laser radiation is applied include hardening and annealing a workpiece by exposure to the radiation. Particular embodiments of the invention herein enables selective removal of a polymer film on a semiconductor substrate by ablative photodecomposition (APD) using intense far-ultraviolet, or shorter wave length, radiation from a pulsed laser requires focusing the laser radiation to provide sufficiently high fluence of laser light energy to ablate a selected area of the polymer to a useful depth in a reasonable time, sometimes referred to as the threshold of fluence of the laser pulses required to produce effective APD of the polymer. This is done with a reflective objective lens system between the laser and the polymer film that focuses the laser beam on a target area of the film surface to a high fluence image of the beam exceeding the threshold for APD. All optical surfaces of the objective len…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.