Semiconductor Wiring Transfer Using Light-Cured Conductive Paste

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Solution Overview

Problem

Existing methods for forming electroconductive elements on substrates face issues such as pattern deformation, incomplete transfer, and increased processing time due to the use of thermoset-resin-containing electroconductive pastes, which are cured through heat treatment, leading to thermal expansion and stress.

Innovation Solution

The method employs an active-light-curable-resin-containing electroconductive paste with a particle diameter of 0.1-20 μm, cured using active light rays, and involves a step of irradiating the paste from the bottom side of the printing plate to form electroconductive elements on a substrate, with an optional intermediate layer to improve transfer and reduce deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If thermoset-resin-containing electroconductive paste is used and cured through heat treatment, then release properties are improved, but pattern deformation occurs and stress arises

Engineering Contradiction:

Improverelease propertiesVSAvoidpattern deformation

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent changes the curing mechanism from thermal (heat treatment) to photochemical (active light rays). This parameter change in the curing method eliminates thermal expansion and contraction that cause pattern deformation, while still achieving proper curing and release properties through photopolymerization of the resin component.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the thermal curing system with an optical curing system. Instead of using heat to cure the thermoset resin, active light rays are used to initiate photopolymerization of the resin, substituting a mechanical/thermal process with an optical one to avoid thermal-related defects.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If heat treatment is maintained for given time, then curing is complete, but processing time increases and throughput decreases

Engineering Contradiction:

Improvecuring completenessVSAvoidthroughput

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent replaces the slow thermal curing process with rapid photopolymerization using active light rays. This substitution allows complete curing to be achieved in a fraction of the time required for heat treatment, thereby increasing throughput without sacrificing curing completeness.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses active light rays to rapidly cure the electroconductive paste in a short time period, effectively 'rushing through' the curing process. This eliminates the need for prolonged heat treatment while still achieving complete curing, thus improving productivity and throughput.

Inventive Principle:

Principle #21Skipping (Rushing through)

3Manufacturing precision

If electroconductive paste is transferred from printing plate to substrate, then wiring pattern is formed, but incomplete transferring occurs due to stress

Engineering Contradiction:

Improvewiring pattern formationVSAvoidtransfer completeness

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent changes the curing method to photopolymerization using active light rays, which eliminates thermal stress that causes pattern deformation. This parameter change ensures that the electroconductive paste maintains its pattern integrity during transfer, preventing incomplete transferring and achieving complete transfer to the substrate.

Inventive Principle:

Principle #35Parameter changes

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 suppresses pattern deformation, enables complete transfer, reduces processing time, and improves throughput by using active light curing, resulting in smoother and more reliable electroconductive elements with reduced electrical field concentration.

Implementation Method 1

a step for irradiating the active-light-curable-resin-containing electroconductive paste 4, with which the recesses 3 in the printing plate 2 are filled, with active light rays and curing the active-light-curable-resin-containing electroconductive paste 4

Methodology Applied

Scientific EffectPhotopolymerisation: Photopolymerisation

Data Source

PatentUS12500121B2Method for forming wiring on semiconductor device

Publication Date: 2025.12.16 CONNECTEC JAPAN CORP

AI summary

A method for forming electroconductive elements into a pattern on a substrate, in which: recesses (3) in a printing plate (2) are filled with an electroconductive paste (4) containing a resin that is curable by active light rays, the active-light-curable-resin-containing electroconductive paste (4) including an active-light-curable resin for which the average particle diameter is set to 0.1-20 μm; the printing plate (2) is superposed on a substrate (1); at least a contact interface portion at which the active-light-curable-resin-containing electroconductive paste (4) contacts the recesses (3) is cured by being irradiated with active light rays from the printing plate (2) side; and then the printing plate (2) is separated from the substrate (1), the active-light-curable-resin-containing electroconductive paste (4) is transferred to the substrate (1), and electroconductive elements (5) having a prescribed pattern are formed on the substrate (1).