Browse Prior Art Database

X-Ray Lithography Mask Alignment Stage

IP.com Disclosure Number: IPCOM000045948D
Original Publication Date: 1983-May-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 3 page(s) / 43K

Publishing Venue

IBM

Related People

Folchi, GA: AUTHOR [+3]

Abstract

An X-ray mask alignment stage is described in which the mask-holding platform is supported for frictionless movement in the mask plane by three or more flexible rods extending from a rigid frame.

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X-Ray Lithography Mask Alignment Stage

An X-ray mask alignment stage is described in which the mask-holding platform is supported for frictionless movement in the mask plane by three or more flexible rods extending from a rigid frame.

In X-ray step-and-repeat lithography it is necessary to quickly align a mask to chip sites on a wafer. This must be done also with great precision. In conventional stage systems, friction/stiction conditions usually limit the positioning of the stage to an accuracy insufficient for overlay in X-ray lithography. A simple mask alignment stage is described which has no friction/stiction or hysteresis problems. Accordingly, the mask can be positioned relative to the wafer very precisely.

A similar photolithographic alignment stage is described in U.S. Patent 3,870,4l6 wherein a platform is supported for frictionless movement in the plane of the stage by three flexible rods extending from an intermediate linking ring which, in turn, is supported by three more flexible rods extending from a rigid frame. Since the intermediate linking ring is supported entirely by frictionless flexible rods and is not directly driven by any actuators, it tends to oscillate in position unless critical damping for the linking ring is provided in some way. An improved geometry is described here in which the intermediate linking ring and the additional three flexible rods have been eliminated. By entirely avoiding the use of an intermediate linking ring, there is no need to prevent it from excessively oscillating.

A plan view of the improved frictionless stage is illustrated in Fig. l, while a cross-sectional view is shown in Fig. 2. The stage consists of a rigid frame l0 connected to a mask support frame l2 via three rods or elastic members l4, l6, l8. The elastic support members l4, l6, l8 only be...