Light-Responsive Release Layer for Wafer Separation

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Solution Overview

Problem

The challenge lies in developing a temporary-fixing technique for a semiconductor wafer to a supporting plate that allows for firm adhesion without causing damage when the supporting plate is stripped, as strong adhesives used for thinning can damage the wafer with reduced strength.

Innovation Solution

A laminate configuration featuring a light-transmissive supporting member, a supported substrate, an adhesive layer, and a release layer with a polymer structure that changes properties upon light absorption, enabling easy separation of the supporting member from the substrate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a strong adhesive is used to firmly adhere the wafer to the supporting plate for thinning, then the adhesion strength is improved, but the wafer is damaged when the supporting plate is stripped from the wafer

Engineering Contradiction:

Improveadhesion strengthVSAvoidwafer damage

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The adhesive system is segmented into two distinct layers: a lower adhesive layer providing strong bonding between the wafer and supporting plate, and an upper release layer providing controlled releasability. This segmentation allows the system to simultaneously achieve strong adhesion for thinning operations and easy separation without wafer damage.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The release layer acts as an intermediary between the wafer and the supporting plate. It mediates the interaction by providing a controlled interface that allows for easy separation after the thinning process, preventing direct damage to the wafer during stripping while maintaining the necessary adhesion strength during processing.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Length of moving object

If the wafer is thinned to 25 μm to 150 μm for high integration, then the chip size is reduced, but the wafer strength decreases making it difficult to handle automatically

Engineering Contradiction:

Improvewafer thicknessVSAvoidwafer strength

Core Design Contradiction:

Length of moving objectVSStrength

Solution Approach 1:

The mechanical properties of the supporting plate are changed by selecting materials with high strength and stiffness (such as glass or hard plastic). This parameter change allows the supporting plate to provide adequate mechanical support to thin wafers (25-150 μm) during handling and processing, compensating for the reduced wafer strength while enabling automated handling.

Inventive Principle:

Principle #35Parameter changes

3Length of moving object

If the wafer is thinned to 25 μm to 150 μm for high integration, then the chip size is reduced, but the wafer becomes susceptible to cracks and warpage

Engineering Contradiction:

Improvewafer thicknessVSAvoidwafer integrity

Core Design Contradiction:

Length of moving objectVSReliability

Solution Approach 1:

The supporting plate serves as a pre-established protective structure that cushions and supports the thinned wafer before any damage can occur. By providing this supportive backbone in advance, the system prevents cracks and warpage that would otherwise occur in ultra-thin wafers during handling and processing operations.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 configuration allows for firm adhesion and subsequent easy separation of the supporting member from the wafer, reducing the risk of damage during processing and handling, and facilitating automation in wafer handling systems.

Implementation Method 1

contains a polymer including, in a repeating unit, a structure having a light absorption property, the polymer changing its property when the polymer absorbs light irradiated via the supporting member

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Data Source

PatentUS9682532B2Laminated body and method for separating laminated body

Publication Date: 2017.06.20 TOKYO OHKA KOGYO CO LTD

AI summary

A laminate including a supporting member which is light transmissive; a supported substrate which is supported by the supporting member; an adhesive layer which is provided on a surface of the supported substrate on which surface the supported substrate is supported by the supporting member; and a release layer, which (i) is provided between the supporting member and the supported substrate and (ii) contains a polymer including, in a repeating unit, a structure having a light absorption property, a property of the polymer being changed when the polymer absorbs light irradiated via the supporting member.