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Browse Prior Art Database

Rotating Multi-Element Block-out-Mask for High Throughput Excimer Laser Processing

IP.com Disclosure Number: IPCOM000112039D
Original Publication Date: 1994-Apr-01
Included in the Prior Art Database: 2005-Mar-26
Document File: 2 page(s) / 49K

Publishing Venue

IBM

Related People

Bohlen, H: AUTHOR [+4]

Abstract

Disclosed is a new step-and-repeat laser projection technique which uses a master mask 1 and a rotating multi-element block-out mask 2. The master mask contains a variety of individual patterns or small pattern arrays that are typical for printed circuit boards, like a master mask layout with nine circular structures arranged on a constant grid. The size of the master mask is determined by the laser beam cross section and the optical system parameters used for projection.

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Rotating Multi-Element Block-out-Mask for High Throughput Excimer
Laser Processing

      Disclosed is a new step-and-repeat laser projection technique
which uses a master mask 1 and a rotating multi-element block-out
mask 2.  The master mask contains a variety of individual patterns or
small pattern arrays that are typical for printed circuit boards,
like a master mask layout with nine circular structures arranged on a
constant grid.  The size of the master mask is determined by the
laser beam cross section and the optical system parameters used for
projection.

      Various block-out patterns are contained as transparent areas
at various locations of a disk.  Overlay of these different block-out
patterns with the master mask produces the corresponding projection
pattern when master mask and block-out mask are arranged as shown in
Fig. 1.

      The disk rotates with constant frequency around its axis 3.
The laser 4 (e.g., a high power, repetitively pulsed excimer laser)
delivers laser pulses synchronized with the rotation of the disk, in
such a way that, whenever the desired block-out pattern overlays the
master mask pattern, the laser is fired.

      Change of the projected pattern is accomplished by introducing
an appropriate delay or advance to the timing of the laser pulse in
reference to the disk rotating at constant frequency.  As shown in
Fig. 2, the transparent features in the block-out mask should be
produced larger in size as compared to the...