Planarization With a Tapered Mold to Prevent Dry Contact
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Solution Overview
Problem
In the planarization process for semiconductor devices, dry contact between the mold and the substrate without the curable material can occur, leading to defects, particles, and reduced durability of the mold and substrate, especially during multiple planarization processes.
Innovation Solution
A planarization method involving a superstrate with a tapered surface is used, where the curable material is supplied to cover the region of the cured film formed under the tapered surface in previous planarization processes, ensuring a liquid film is formed to prevent dry contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a mold with a tapered portion is used to suppress curable material exudation, then curable material exudation is reduced, but dry contact occurs at the outer peripheral portion
Solution Approach 1:
The invention applies different surface properties to different regions of the mold: the central region has a flat surface for normal planarization, while the outer peripheral region has a tapered surface with reduced friction. This local differentiation allows the curved surface to reduce adhesion and prevent dry contact without causing excessive exudation in the central planarization area.
Solution Approach 2:
The invention changes the friction parameter at the outer peripheral portion of the mold by creating a tapered curved surface. This parameter change reduces the friction between the mold and substrate at the periphery, preventing the mold from coming into direct contact with the substrate without curable material (dry contact).
2Manufacturing precision
If multiple planarization processes are performed to improve surface planarity, then planarity is improved, but dry contact occurs due to interference from cured bulging portions
Solution Approach 1:
The invention performs preliminary action by modifying the mold surface structure before subsequent planarization processes. The tapered curved surface is created in advance to reduce friction, which prevents dry contact during later planarization steps when cured bulging portions from previous processes would otherwise cause interference.
3Reliability
If the application amount of curable material is increased to prevent dry contact, then dry contact is prevented, but curable material exudation increases
Solution Approach 1:
The invention applies different surface properties to different regions of the mold: the central region has a flat surface for normal planarization, while the outer peripheral region has a tapered surface with reduced friction. This local differentiation allows the curved surface to reduce adhesion and prevent dry contact without causing excessive exudation in the central planarization area.
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 method effectively prevents dry contact and associated defects, maintaining the durability of the mold and substrate, even after multiple planarization processes, by ensuring continuous coverage with the curable material.
Implementation Method 1
An imprint apparatus that employs the photo-curing method molds, using a mold, a photo-curable material supplied to a shot region on a substrate, cures the curable material by light irradiation
Data Source
AI summary
A planarization method of repeatedly performing a planarization process a plurality of times on the same surface of a substrate is provided. The superstrate is provided with a tapered surface connecting a side end face to a flat surface forming a lower surface facing the substrate. In a second planarization process after a first planarization process, a curable material is supplied so as to cover a region of a cured film formed under the tapered surface in the first planarization process with a liquid film formed in the second planarization process.