Browse Prior Art Database

EB Proximity Printer With Increased Throughput

IP.com Disclosure Number: IPCOM000046431D
Original Publication Date: 1983-Jul-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 60K

Publishing Venue

IBM

Related People

Asch, K: AUTHOR [+6]

Abstract

An electron beam (EB) lithographic system for proximity printing uses complementary masks on which island-like structures are supported by thin grids differently positioned in the two masks, thus requiring only half the exposure time of conventional complementary masks.

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EB Proximity Printer With Increased Throughput

An electron beam (EB) lithographic system for proximity printing uses complementary masks on which island-like structures are supported by thin grids differently positioned in the two masks, thus requiring only half the exposure time of conventional complementary masks.

In known EB lithographic systems with complementary masks (e.g., U.S. Patent 4,169,230), the patterns to be printed are broken up and distributed on both masks, so that there are no island-like structures. Each of the complementary masks is then aligned on the resist-coated wafer and exposed at the full electron beam dose.

To reduce the exposure time, it is proposed to use complementary masks which are each provided with the complete mask pattern, including island-like structures held by supporting grids, whose positions in the two masks differ. Fig. 1 shows an example of an island-like structure l0 surrounded by a rectangular open area 11.

The complementary masks for printing the structure are shown in Figs. 2A and 2B. In the two complementary masks, islands l0 are identical and supported by elements (very thin bridges) 20a, 20b which are offset with respect to each other in the two masks.

During printing, each of the complementary masks (Figs. 2A and 2B) receives only 50% of the nominal exposure dose, so that areas not shaded by supporting elements 20a, 20b are exposed l00%. Resist areas, positioned directly under supporting elements 20a, 20b, recei...