Partial Curing Adhesive Layer for Wafer Bonding

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Solution Overview

Problem

Current methods for temporarily bonding substrates in the semiconductor industry face challenges such as premature detachment due to high temperatures and stress, difficulty in debonding, and the need for complex and costly multi-layer systems, which can lead to substrate damage and increased processing costs.

Innovation Solution

A method and device for temporarily bonding substrates using a bonding adhesive layer where only a partial area is cured, allowing for controlled adhesive strength and non-destructive separation, eliminating the need for additional anti-adhesive coatings and reducing process steps, with curing achieved through electromagnetic radiation, heat, or other methods.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the bonding adhesive layer is fully cured to provide strong bonding force, then the bonding strength is improved, but the debonding process becomes difficult and complex

Engineering Contradiction:
Improvebonding strengthVSAvoiddebonding process
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The bonding adhesive layer is divided into two distinct regions: a first region that is fully cured to provide strong bonding, and a second region that remains uncured or partially cured to enable easy debonding. This spatial segmentation of curing states allows the adhesive to simultaneously provide both strong bonding and easy release properties.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the bonding adhesive layer have different curing degrees tailored to their specific functions. The first region (peripheral area) is fully cured for strong bonding, while the second region (central area) remains uncured or partially cured for easy debonding. This local differentiation of material properties resolves the contradiction between bonding strength and debonding ease.

Inventive Principle:
Principle #3Local quality

2Ease of operation

If a thermoplastic with low glass transition temperature is used to enable easy debonding, then the debonding process is simplified, but delamination occurs at the wafer edge during high temperature processing

Engineering Contradiction:
Improvedebonding processVSAvoidbonding stability during processing
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The bonding adhesive layer exhibits different thermal-stress resistance properties in different regions. The first peripheral region is fully cured and provides high thermal-stress resistance to prevent delamination during high-temperature processing, while the second central region remains uncured or partially cured to enable easy debonding after processing.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The bonding adhesive layer is segmented into a first region with high cross-linking density (fully cured) for thermal stability and a second region with low cross-linking density (uncured or partially cured) for easy debonding. This segmentation allows each region to optimize its performance for its specific function.

Inventive Principle:
Principle #1Segmentation

3Strength

If cross-linking materials are used as bonding adhesives to provide strong bonding, then the bonding strength is improved, but the debonding process requires strong chemicals and becomes very difficult

Engineering Contradiction:
Improvebonding strengthVSAvoidchemical attack on substrate
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The bonding adhesive layer is segmented such that only the first peripheral region contains fully cross-linked material for strong bonding, while the second central region remains uncured or partially cured, avoiding the need for strong chemicals during debonding and preventing chemical attack on the substrate.

Inventive Principle:
Principle #1Segmentation

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 provides a high bonding force for all necessary process steps while enabling non-destructive separation of thin substrates, reducing costs and complexity, and allowing for the use of a wide variety of substrates with improved protection of substrate structures.

Implementation Method 1

curing only a partial area of the bonding adhesive layer

Methodology Applied
Scientific EffectCuring: Photopolymerisation

Implementation Method 2

curing achieved through electromagnetic radiation, heat, or other methods

Methodology Applied
Scientific EffectElectromagnetic radiation: Electromagnetic Induction

Implementation Method 3

a remaining region of the bonding adhesive layer not curing or at least not curing significantly becomes. The loss of adhesion properties is usually accompanied by a reduction in viscosity

Methodology Applied
Scientific EffectAdhesive property loss: Adhesive

Data Source

PatentEP3440695B1Method and apparatus for bonding of two substrates
Publication Date: 2019.10.02 EV GRP E THALLNER GMBH
  • EP3440695B1 patent drawingFigure 1a~1e
  • EP3440695B1 patent drawingFigure 2a~2b
  • EP3440695B1 patent drawingFigure 3a~3b

AI summary

The invention relates to a method and a device for bonding two substrates.