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US 6,187,480 B1Granted
Alternating phase-shifting mask
AssigneeUnited Microelectronics Corp.
InventorChien-Chao Huang
Life of this patent
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Abstract
A alternating phase shift mask comprises a phase shift layer formed between a light-penetrable substrate and a sheltering layer. The sheltering layer covers a sheltered region formed on the phase shift layer. The section of the light-penetrable substrate exposed by the phase shift layer and the sheltering layer is defined as a penetrating region. Incident light forms a phase angle of 180° in the penetrating region and the sheltering layer to make constructive interference and to enhance the resolution of photolithographic process.
Claims5
A method of fabricating an alternating phase shift mask, consisting of:
- providing a light-penetrable substrate;
- forming a phase shift layer and a sheltering layer abutting against the light-penetrable substrate;
- defining the sheltering layer to expose a desired phase-shift portion and a desired light-transmitting portion of the phase shift layer, wherein a portion under the defined sheltering layer is a sheltered portion;
- forming a photoresist layer with an opening on the sheltering layer and the phase shift layer, wherein the opening exposes the light-transmitting portion of the phase shift layer and a portion of the sheltering layer abutting the light-transmitting portion, the opening of the photoresist layer has an erroneous deviation from an edge of the light-transmitting portion;
- etching the phase shift layer at the light-transmitting portion to expose the light-penetrable substrate, using the photoresist layer and the sheltering layer as a mask, wherein the sheltering layer determines the edge of the light-transmitting portion;
- and
- removing the photoresist layer.
4 more elements
Dependencies are inferred from the claim text.