Imprint Mold Light-Shielding Layout for Multilayer Wiring Pads
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Solution Overview
Problem
The existing imprint method for forming multilayer wiring structures faces challenges such as residual film obstruction in interlayer connection vias, air bubble defects in wiring recesses, mold breakage, warping of insulating material layers, and damage to light-shielding materials due to chemical treatments, leading to inaccurate and unreliable pattern formation.
Innovation Solution
A method involving a mold with a rugged structure and a light-shielding layer at the top portion of projected portions, where a photo-curing insulating resist is cured while leaving the resist between the light-shielding layer and the transfer base material uncured, allowing for easy removal of residues and preventing air bubbles, combined with a protective film to prevent oxidation and enhance durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a photo-curing insulating resist is cured by irradiation with light from the mold side to form an insulating material layer, then the pattern structure is formed with high precision, but a residual film of the insulating material layer remains between the deeper recesses for forming interlayer connection vias and the pad portions in a lower layer, obstructing connection
Solution Approach 1:
The mold's rugged structure is segmented into multiple height levels (higher projected portions for interlayer connection vias and lower projected portions for wiring), enabling selective light blocking and differential curing of the photo-curing insulating resist to prevent residual film formation in critical connection areas
Solution Approach 2:
The mold is designed with light-shielding properties at specific regions before the curing process, preliminarily preventing light from reaching certain areas to avoid residual film formation, thereby ensuring reliable interlayer connections before the actual connection process begins
2Reliability
If a dry etching treatment is performed to remove the residual film, then the residual film is removed, but the wall surfaces of the shallower recesses for wiring are roughened, lowering high-frequency characteristics
Solution Approach 1:
The light-shielding function is extracted and concentrated specifically at the higher projected portions of the mold corresponding to interlayer connection via regions, allowing selective prevention of residual film formation only where needed, while leaving the wiring regions unaffected and maintaining their surface quality
Solution Approach 2:
The mold structure implements local quality by providing light-shielding properties only at specific higher projected portions for via formation, while maintaining transparency or different properties in regions corresponding to wiring areas, thereby achieving selective residual film prevention without affecting wiring surface quality
3Productivity
If the mold is pressed against the transfer base material to fill the rugged structure with photo-curing insulating resist, then the pattern structure is formed, but air bubbles remain in the recesses, causing defects
Solution Approach 1:
The mold surface is preliminarily treated with a release coating before the imprint process, creating a non-stick surface that prevents air bubbles from becoming trapped during pressing, thereby enabling defect-free pattern formation while maintaining high production efficiency
Solution Approach 2:
A release coating acts as an intermediary layer between the mold and the photo-curing insulating resist, facilitating smooth filling of the rugged structure while preventing air bubble entrapment and enabling easy mold separation without damaging the formed pattern structure
4Reliability
If chemical treatments are used to remove residues, then the residual film is removed, but the light-shielding material is damaged, reducing mold durability
Solution Approach 1:
The design accepts that the light-shielding portions may be sacrificial or replaceable, focusing on achieving reliable pattern formation in each use, while the overall mold structure remains durable and reusable through careful material selection and design
Solution Approach 2:
The approach changes the chemical resistance parameters of the light-shielding material or modifies the chemical treatment parameters to reduce their interaction, thereby preventing damage to the light-shielding material while still achieving effective residue removal for reliable pattern structures
5Manufacturing precision
If the mold has a rugged structure with higher and lower projected portions, then deeper recesses for interlayer connection vias and shallower recesses for wiring are formed, but the complex structure increases manufacturing difficulty
Solution Approach 1:
The complex rugged structure is segmented into standardized height levels (higher and lower projected portions) that can be manufactured using conventional molding techniques, reducing manufacturing difficulty while maintaining the ability to form multi-depth recesses with high precision
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 enables the formation of pattern structures with high accuracy, reduces warping, and maintains mold integrity by preventing damage to the light-shielding layer, resulting in reliable and precise multilayer wiring structures.
Implementation Method 1
irradiation with light from the mold side is conducted to cure the photo-curing resin composition, thereby forming a resin layer
Implementation Method 2
a through-hole forming light-shielding layer being provided at a desired part of a top portion flat surface of the projected portion for forming the pad
Implementation Method 3
combined with a protective film to prevent oxidation and enhance durability
Data Source
AI summary
A mold includes a mold base material and a rugged structure located at a main surface of the mold base material. The rugged structure includes a plurality of linearly shaped projected portions for forming wiring, and a circularly shaped projected portion for forming a pad portion, in which a light-shielding layer is provided at a top portion flat surface of the circularly shaped projected portion for forming the pad portion.