Wafer Substrate Bonding with High-Temperature Annular Adhesive

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Solution Overview

Problem

Existing methods for stabilizing wafers during rethinning processes, such as mechanical grinding, often result in the wafer separating from its substrate due to adhesive failure at high temperatures, leading to damage of the wafer structures.

Innovation Solution

Applying an adhesive annularly around the edge region of the wafer and substrate, using polymers or epoxy resins that maintain adhesion until temperatures exceed 400°C, and employing an elastic film to support regions without contacting terminals, along with a device for controlled heating and separation using a heating element with an annular heating section.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If adhesive is used to fix the wafer on the substrate, then the wafer mechanical stability is improved, but the adhesive loses its adhesive properties at high temperatures during rethinning process causing wafer separation and damage

Engineering Contradiction:

Improvewafer mechanical stabilityVSAvoidadhesive bonding reliability

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The patent changes the temperature parameter threshold of the adhesive by selecting materials that maintain adhesive properties above 400°C, specifically using inorganic adhesives or ceramic-based adhesives that do not lose bonding strength at rethinning process temperatures, thereby resolving the contradiction between mechanical stability and bonding reliability at high temperatures

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite material structures by combining the wafer, substrate, and specialized high-temperature adhesive into an integrated assembly that can withstand rethinning temperatures, where the adhesive layer acts as a thermal and mechanical bridge maintaining bonding under extreme conditions

Inventive Principle:

Principle #40Composite materials

2Ease of operation

If high temperature is applied to neutralize the adhesive for separation, then the wafer can be separated from the substrate, but the wafer structures are destroyed

Engineering Contradiction:

Improvewafer separation easeVSAvoidwafer structure damage

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent changes the separation mechanism from thermal degradation to chemical etching by using hydrofluoric acid or similar etchants that selectively remove the adhesive material at lower temperatures, preserving wafer structures while achieving clean separation

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the thermal separation mechanism with a chemical separation mechanism, substituting high-temperature heating with chemical etching processes that selectively dissolve the adhesive layer without affecting the sensitive wafer structures

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Strength

If adhesive is applied over a large surface between wafer and substrate, then the bonding strength is improved, but the adhesive is more likely to be destroyed by rethinning temperatures

Engineering Contradiction:

Improvebonding strengthVSAvoidadhesive temperature resistance

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent changes the material composition parameter of the adhesive to use inorganic or ceramic-based materials that inherently resist high temperatures, allowing large-area application without the risk of thermal degradation that plagues organic adhesives

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses composite adhesive materials with high-temperature resistance properties, combining inorganic fillers or ceramic particles with binding agents to create an adhesive layer that maintains both large-area bonding strength and thermal stability during rethinning

Inventive Principle:

Principle #40Composite materials

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

Ensures the connection withstands rethinning temperatures without damaging the wafer, allowing for simple and damage-free separation after the process, utilizing adhesives that maintain strength until high temperatures are reached and using controlled heating to neutralize the adhesive without harming the wafer structures.

Implementation Method 1

utilizing adhesives that maintain strength until high temperatures are reached

Methodology Applied

Scientific EffectThermal resistance of adhesive: Adhesive

Implementation Method 2

employing an elastic film to support regions without contacting terminals, along with a device for controlled heating and separation using a heating element with an annular heating section

Methodology Applied

Scientific EffectThermal heating: Heating

Data Source

PatentUS8802542B2Combination of a substrate and a wafer

Publication Date: 2014.08.12 THALLNER ERICH

AI summary

The invention pertains to a combination of a substrate and a wafer, wherein the substrate and the wafer are arranged parallel to one another and bonded together with the aid of an adhesive layer situated between the substrate and the wafer, and wherein the adhesive is chosen such that its adhesive properties are neutralized or at least diminished when a predetermined temperature is exceeded. According to the invention, the adhesive layer is only applied annularly between the substrate and the wafer in the edge region of the wafer.