Browse Prior Art Database

Proximity Printing Photomask

IP.com Disclosure Number: IPCOM000076238D
Original Publication Date: 1972-Feb-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 35K

Publishing Venue

IBM

Related People

Moreau, WM: AUTHOR

Abstract

The mask 1 provides for circulation of a fluid within the device area of a photomask for continuous proximity printing of a substrate 7, such as a semiconductor wafer. In proximity printing, the mask with a device pattern 8 is brought in near contact with gaps 6 of usually less than one mil. This mask consists of a fixed spacer gap 2 to contain a circulation fluid 3 and to establish the proximity gap. The fluid is circulated through tubes 4 and 5 which have been drilled through the transparent substrate 1.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 100% of the total text.

Page 1 of 2

Proximity Printing Photomask

The mask 1 provides for circulation of a fluid within the device area of a photomask for continuous proximity printing of a substrate 7, such as a semiconductor wafer. In proximity printing, the mask with a device pattern 8 is brought in near contact with gaps 6 of usually less than one mil. This mask consists of a fixed spacer gap 2 to contain a circulation fluid 3 and to establish the proximity gap. The fluid is circulated through tubes 4 and 5 which have been drilled through the transparent substrate 1.

Since a fixed gasket is employed, the arrangement is amenable to continuous wafer processing. Circulation fluids such as immersion oils decrease the refraction of the usual air gap in proximity printing, thereby improving resolution. External pumps fill the proximity space before exposure and evacuate after exposure for the next wafer.

Since air is displaced by the fluid, oxygen-sensitive resists can be effectively employed in this mask arrangement. The photoresist may also be developed if developing solution is circulated after removal of the immersion fluid. If a vacuum gasket is used, air may be removed from the space and a proximity exposure in vacuum can be effected. Nitrogen gas may also be a substitute fluid for circulation during exposure of oxygen-sensitive resists.

1

Page 2 of 2

2

[This page contains 2 pictures or other non-text objects]