Browse Prior Art Database

E Beam Alignment Masks for Processing FET Planar IS Structures

IP.com Disclosure Number: IPCOM000088076D
Original Publication Date: 1977-Apr-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 2 page(s) / 54K

Publishing Venue

IBM

Related People

Protschka, HA: AUTHOR [+2]

Abstract

A technique is disclosed for obtaining precise alignment of a sequence of electron (E) beam masking levels using an E-beam-delineated array of grooves in the silicon (Si) substrate, which is obliterated between the first and the second masking steps by the growth of an oxide layer.

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E Beam Alignment Masks for Processing FET Planar IS Structures

A technique is disclosed for obtaining precise alignment of a sequence of electron (E) beam masking levels using an E-beam-delineated array of grooves in the silicon (Si) substrate, which is obliterated between the first and the second masking steps by the growth of an oxide layer.

The first step (Fig. 1) consists of forming an array of precisely delineated E- beam grooves 1 in an initial oxide layer 2 on Si substrate 3.

The second step (Fig. 2) entails the growth of a new oxide layer 4 which consumes a portion of the Si substrate 3, maintaining the original contour of the delineated grooves 1, now in the Si substrate 5.

The final step (Fig. 3) entails the use of an optical mask having a significantly lower resolution to open a relatively large hole 6 in the region containing the well- defined E-beam grooves 5. The edges 7 of the optical mask need not be exactly aligned with the refined E-beam produced grooves. All oxide 2 and 4 in the region exposed by the optical mask is removed, thereby causing the grooves 5, now present in the Si substrate 3, to be available for aligning the second E-beam masking level.

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