Photomask, photomask fabrication method, and semiconductor device fabrication method
AssigneeFujitsu Semiconductor Limited
InventorNaoyuki Ishiwata
Life of this patent
Estimating the term…
Abstract
A photomask capable of preventing a pattern outside a chip region from being transferred onto a wafer. A non-circuit pattern (a monitor pattern for measuring the accuracy of the position of a mask pattern, for example) formed by making openings in which a phase shift layer is exposed only in a light shielding layer is located around the chip region where the light shielding layer is removed and where the phase shift layer in which openings corresponding to circuit patterns are made is exposed. This prevents the non-circuit pattern from being transferred onto the wafer by the influence of a flare.
Claims17
A photomask comprising:
- a transparent substrate;
- a phase shift layer for shifting a phase of exposure light on the transparent substrate;
- a light shielding layer on the phase shift layer;
- a circuit pattern, formed in a chip region, including a first opening through the phase shift layer and exposing the transparent substrate;
- a first non-circuit pattern, formed outside of the chip region and in an area within fifteen millimeters distance from the chip region, including a second opening through the light shielding layer and exposing the phase shift layer;
- and
- a second non-circuit pattern for adjusting the relative positions of the photomask and an exposure system, formed outside of the chip region and in an area over fifteen millimeters distance from the chip region, including a third opening through the light shielding layer and the phase shift layer and exposing the transparent substrate, wherein:
- in the chip region, the light shielding layer is removed;
- and
- the transparent substrate under the second opening is wholly covered with the phase shift layer.
A method for fabricating a photomask comprising:
- forming a phase shift layer shifting a phase of exposure light and a light shielding layer in order on a transparent substrate;
- forming a first opening in the light shielding layer in a chip region;
- forming a second opening in the light shielding layer in a non-circuit region outside of the chip region and in an area within fifteen millimeters distance from the chip region;
- forming a third opening in the light shielding layer in the non-circuit region outside of the chip region and in an area over fifteen millimeters distance from the chip region;
- forming a resist pattern covering the second opening and exposing the chip region and the third opening;
- etching the phase shift layer using the resist pattern and the light shielding layer as masks;
- and
- removing the light shielding layer in the chip region using the resist pattern as a mask;
- wherein the transparent substrate under the second opening is wholly covered with the phase shift layer.
A method for fabricating a semiconductor device comprising:
- forming a phase shift layer shifting a phase of exposure light and a light shielding layer in order on a transparent substrate;
- forming a first opening in the light shielding layer in a chip region;
- forming a second opening in the light shielding layer in a non-circuit region outside of the chip region and in an area within fifteen millimeters distance from the chip region;
- forming a third opening in the light shielding layer in the non-circuit region outside of the chip region and in an area over fifteen millimeters distance from the chip region;
- forming a resist pattern covering the second opening and exposing the chip region and the third opening;
- etching the phase shift layer using the resist pattern and the light shielding layer as masks;
- removing the light shielding layer in the chip region using the resist pattern as a mask;
- and
- after removing the light shielding layer in the chip region, performing a exposure process to a resist film over a semiconductor substrate using the transparent substrate as a photomask;
- wherein the transparent substrate under the second opening is wholly covered with the phase shift layer.
Dependencies are inferred from the claim text.