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Advanced Mask and Reticle Technology for VLSI Sub-Micron Microelectronics Devices

Objective

The fabrication of masks and reticles forms a key step in the manufacture of integrated circuits. As VLSI circuit complexity increases, the role of mask-making becomes increasingly demanding and the quality criteria even more exacting, so that improvements in high-quality mask technology directly affect the competitiveness of Europe's semiconductor industry.
This project addressed specific areas of both E-beam and optical mask-making processes to develop new equipment, materials and processes. The objective was to combine such developments to create an enhanced mask and reticle technology to satisfy the waferfabrication requirements for advanced and complex devices.
The work-plan included:
-the production of 5X reticles containing 2micronminimum feature size
-laser pattern generation of 5Xreticles
-control of 1micron dimensions at 1X to a tolerance of +/-0.1micron
-micro-edge acuity of chrome oxide films to +/-0.05micron or better
-the development of chemical processes compatible with Ebeam and UV optical resist technologies
-the manufacture of high yield/low defect density masks and reticles at 1X and 5X
the development of new and existing resists for Ebeam and optical microlithography
-the establishment of European suppliers of high-quality materials and superior equipment.
Equipment has been developed based on technology for the production of high precision masters used in integrated circuit production. The edge sharpness is outstanding. With minor modification the equipment can be used for the etching of integrated circuit (IC) wafers.

The fabrication of masks and reticles forms a key step in the manufacture of integrated circuits. As very large scale integration (VLSI) circuit complexity increases, the role of mask making becomes increasingly demanding. This project addressed specific areas of both electron (E) beam and optical mask making processes to develop new equipment, materials and processes. The objective was to combine such developments to create an enhanced mask and reticle technology to satisfy the wafer fabrication requirements for advanced and complex devices. The work plan included: the production of 5X reticles containing 2 micron minimum feature size; laser pattern generation of 5X reticles; control of 1 micron dimensions at 1X to a tolerance of +/- 0.1 micron; microedge acuity of chrome oxide films to +/- 0.05 micron or better; the development of chemical processes compatible with E beam and ultraviolet optical resist technologies; the manufacture of high yield/low defect density masks and reticlesat 1X and 5X; and the development of new and existing resists for E beam and optical microlithography. A working prototype for a 2 laser pattern generator (PG), the basic machine for the production of these advanced masks, was installed and tested. Valuable experience was gained on laser exposure of resists, though improvements in the PG exposure rate could still be made. Studied on chrome blanks, resist technology and wet etching, both for E beam and optical processes, were successfully assessed. The following prototype equipment was evaluated within the project: 2 laser illuminator for optical pattern generators, advanced masks and reticle cleaning station, novel dry etch chrome mask equipment, and a new electron beam resist.
A working prototype of a twolaser Pattern Generator (PG), the basic machine for the production of these advanced masks, was installed and tested. Valuable experience was gained on laser exposure of resists, though improvements in the PG exposure rate cou ld still be made. Studies on chrome blanks, resist technology and wet etching, both for Ebeam and optical processes, were successfully assessed.
The following prototype equipment was evaluated within the project: twolaser illuminator for optical pattern generators, advanced masks and reticle cleaning station, novel dry etch chrome mask equipment, and a new electron-beam resist.

Coordinator

PLESSEY SEMICONDUCTORS
Address
Fields New Road
OL9 8NP Chadderton, Oldham
United Kingdom

Participants (5)

BMP Plasmatechnologie
Germany
Address
Carl-zeiss-straße 14
85748 Garching Bei München
British Telecom plc (BT)
United Kingdom
Address
British Telecom Laboratories Martlesham Heath
IP5 7RE Ipswich
IMEC VZW
Belgium
Address
Kapeldreef
3030 Heverlee
Siemens AG
Germany
Address
Balanstraße 73
81541 München
Valvo Unternehmensbereich
Germany
Address
Burchardstraße 19
20095 Hamburg