Process for making masks with structures in the submicron range

US5055383A · kind A · utility

Assignee

• International Business Machines Corporation · US

Inventors

• Otto Koblinger · Ditzingen, DE
• Klaus Meissner · Herrenberg, DE
• Reinhold Muhl · Altdorf, DE
• Hans-Joachim Trumpp · Stuttgart, DE
• Werner Zapka · Gärtringen, DE

Key dates

• Filing date: Oct 12, 1989
• Grant date: Oct 8, 1991
• Expiry date: Oct 12, 2009

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01L21/31144
• WIPO field: Semiconductors
• WIPO sector: Electrical engineering

Abstract

In the course of the process for making masks with structures in the submicrometer range, initially structures of photoresist or polymer material with horizontal and substantially vertical sidewalls are produced on a silicon substrate covered with an oxide layer. This is followed by a layer of silicon nitride which is deposited by LPCVD. The resultant structure is planarized with a photoresist which is etched back until the start of the vertical edges of the sidewall coating formed by the nitride layer is bared on the photoresist structures. In a photolithographic step, a trimming mask is produced on the surface of the nitride layer and the planarizing resist. The bared regions of the nitride layer are then removed by isotropic etching. The dimensions A-B of the openings defined after removal of the nitride layer from the vertical surfaces of the photoresist structures are transferred to the oxide layer by anisotropic etching. Concurrently with these structures of minimum line width, registration marks are generated which allow the adjustment necessary for a further photolithographic step to be carried out with maximum accuracy. After removal of the trimming mask, the planarizing r…