The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 19, 1992
Filed:
Sep. 14, 1989
Yehuda Nachshon, Timrat, IL;
Other;
Abstract
A process and a system for the complete stripping of the photoresist layer from semiconductor wafers after each processing step (lithography step) in a multi-step production process. At the end of each such step the photoresist must be removed, preparing the wafer for the next step, and such removal is also required after the final processing step. Up to 15 or more steps are needed in such wafer production process. According to the invention a high intensity pulsed laser beam sweeps the wafer surface as a narrow, preferably rectangular and strip the photoresist by sweeping the entire surface of the wafer. Pulse duration is generally shorter than 500 nano-sec (nsec) and preferably about 10 to 100 nsec, with much larger time intervals between pulses. The interaction of the beam with the photoresist ablates the photoresist. The ablation proceeds stepwise, each pulse ablating a certain area of the photoresist to a certian depth, and this without any damage to the processed wafer. The sweep suffices to completely remove the photoresist, reading the wafer for the next process step; the overall duration of the removal being short.