Imprint Curing at Wafer Edges to Prevent Mold Adhesion
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Solution Overview
Problem
The imprint process for semiconductor devices often results in pattern defects due to imprint material adhering to the mold, particularly at the outer edge portions of the substrate, which are not adequately contacted and cured, leading to issues in subsequent shot regions.
Innovation Solution
A shaping method where the light irradiation for curing the imprint material is adjusted to provide a smaller irradiation light amount per unit area for the outer edge portions, and additional light irradiation is performed after mold separation, ensuring the material remains uncured on the mold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If uniform light irradiation is applied to the entire substrate including outer edge portions, then complete curing of the imprint material is achieved, but the imprint material adheres to the mold causing pattern defects
Solution Approach 1:
The patent applies different light irradiation amounts to different regions of the substrate. Specifically, the outer edge portions receive a smaller irradiation light amount per unit area compared to the central portions. This local differentiation prevents adhesion at the edges while maintaining complete curing at the central regions, directly resolving the contradiction between complete curing and preventing adhesion.
2Reliability
If additional light irradiation is performed after mold separation, then uncured material on the mold is cured, but the material may adhere to the mold before curing
Solution Approach 1:
The patent performs additional light irradiation after mold separation to cure any remaining uncured imprint material on the mold. This preliminary curing action prevents the material from adhering to the mold in a cured state during subsequent processing, thereby reducing pattern defects in the next shot region.
3Productivity
If the imprint process is performed on outer edge portions with warpage or stepped portions, then substrate utilization is improved, but the imprint material is not sufficiently contacted by the mold
Solution Approach 1:
The patent recognizes that outer edge portions with warpage or stepped portions require different processing conditions. By supplying imprint material as droplets and applying a smaller irradiation light amount per unit area to these regions, the patent enables successful imprinting on problematic areas without compromising overall imprint quality, thus improving substrate utilization.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces the occurrence of pattern defects by preventing the imprint material from adhering to the mold in a cured state, thereby improving the yield of product chips.
Implementation Method 1
an imprint material on a substrate is cured by light irradiation while a mold and the imprint material are in contact with each other
Data Source
AI summary
The present invention provides a shaping method of performing a process of shaping a composition on a substrate by using a mold, with respect to each of a plurality of regions on the substrate, wherein the process includes curing the composition on the substrate by light irradiation in a state where the mold and the composition are in contact with each other and separating the mold from the cured composition, the plurality of regions including a first region having an outer edge portion of the substrate, and the light irradiation is performed so as to make an irradiation light amount for the outer edge portion become smaller than that for a portion other than the outer edge portion, in the curing for the first region, and the first region is additionally irradiated with light after the separating for the first region.