Appartus for, and methods of, inscribing patterns on semiconductor wafers

US4727381A · kind A · utility

Inventors

• Josef F. Bille · Heidelberg, DE
• Siegfried Hunklinger · Heidelberg, DE

Key dates

• Filing date: Jul 23, 1985
• Grant date: Feb 23, 1988
• Expiry date: Jul 23, 2005

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01L21/0275
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

An energy (i.e. laser) beam directed to a photoresist layer is scanned in a first direction through lines progressively displaced in a second coordinate direction. In this way, stripe areas of a wafer are exposed sequentially in a first direction with a thickness dependent upon the size of the laser spot focussed on the beam. The beam scanning rate is adjustable to obtain a time coincidence between the occurrence of markers in a computer and the scanning of a particular position in each line. The beam is modulated during the scan to inscribe a pattern on the layer. The beam is focussed on, and reflected from, the photoresist layer. The reflection is used to maintain the focussing of the beam on the layer by adjusting individual elements in an active mirror in accordance with the reflected beam characteristics. The beam may be split into a plurality of beams displaced from one another in the first direction by providing associated pairs of spherical facets in a lens system and directing portions of the beam between the facets in each pair. Such beams are synchronously scanned to increase the scanning frequency. A second beam with different characteristics than the first beam may be …