Multiple resist layer photolithographic process
AssigneeUnited Microelectronics Corp.
InventorsI-Hsiung Huang, Jiunn-Ren Hwang
Life of this patent
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Abstract
A multiple resist layer photolithographic process. A substrate having an insulation layer and a first photoresist layer sequentially stacked thereon is provided. A first light-exposure is conducted to transfer a pattern on a photomask to the first photoresist layer, thereby forming a first exposure pattern. A post-exposure baking is carried out and then the first photoresist layer is developed. A second photoresist layer is formed over the patterned first photoresist layer. A second photo-exposure is conducted to transfer the pattern on the same photomask to the second photoresist layer, thereby forming a second exposure pattern. The second exposure pattern and the first exposure pattern are aligned. Finally, the second photoresist layer is developed.
Claims8
A method of increasing depth of focus in a photolithographic process, comprising the steps of:
- providing a substrate that can be divided into a first region and a second region;
- forming an insulation layer over the substrate, wherein a step height difference exists between the first region and the second region;
- forming a first photoresist layer over the insulation layer in both the first region and the second region;
- performing a first photolithographic process to transfer a pattern on a photomask to the first photoresist layer on the first region and the second region, thereby forming a first pattern that exposes a portion of the insulation layer;
- forming a second phtotresist layer over the first phtotresist layer on the first region and the second region;
- and
- performing a second photolithographic process to transfer the pattern on the photomask to the second photoresist layer on the first region and the second region, thereby forming a second pattern, wherein the second pattern is aligned with the first pattern so that the portion of the insulation layer is exposed again.
Dependencies are inferred from the claim text.