Dual-Layer Temporary Wafer Bonding for Harsh Process Stability
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Solution Overview
Problem
Existing temporary wafer bonding materials face challenges in maintaining adhesion and stability under harsh processing conditions, such as extreme thermal cycling, mechanical stress, and exposure to chemicals like epoxy mold compounds, which can lead to delamination failures.
Innovation Solution
A dual-layer bonding method using a first bonding composition with a thermoplastic material and a second bonding composition that is thermosetting, where at least one of the bonding layers includes a bond line adhesion promoter that covalently bonds with a component in the other layer, enhancing adhesion and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-layer bonding material is used, then the process is simple, but adhesion strength and thermal stability under harsh conditions are insufficient
Solution Approach 1:
The patent employs a dual-layer bonding material system where a thermoplastic layer is combined with a thermosetting layer. The thermoplastic layer provides initial bonding and ease of processing, while the thermosetting layer delivers superior thermal stability and adhesion strength. This composite structure resolves the contradiction by integrating materials with complementary properties to achieve both simplicity and reliability.
Solution Approach 2:
Each layer of the bonding material is designed with specific localized properties: the thermoplastic layer is optimized for low-temperature bonding and flexibility, while the thermosetting layer is optimized for high-temperature stability and strong adhesion. This local differentiation allows each layer to perform its specific function optimally, resolving the contradiction between simplicity and reliability.
2Strength
If bonding temperature is increased to improve adhesion, then bonding strength increases, but thermal stability over wide temperature ranges deteriorates
Solution Approach 1:
The dual-layer system allows the thermoplastic layer to provide bonding at lower temperatures while the thermosetting layer maintains stability at higher temperatures. This composite approach resolves the contradiction by distributing the thermal load across materials with different thermal characteristics, achieving both strong bonding and wide temperature range stability.
Solution Approach 2:
The patent utilizes phase transition parameters of the thermoplastic layer (melting and solidification) for bonding, then relies on the thermosetting layer's crosslinked structure for high-temperature stability. This parameter-based approach allows bonding strength to be achieved at low temperatures while maintaining thermal stability across wide temperature ranges.
3Strength
If robust bonding layer is used to protect device wafer, then physical protection improves, but ease of separation and cleaning deteriorates
Solution Approach 1:
The thermoplastic layer is designed to be mechanically robust for protection during processing, while the thermosetting layer provides controlled separation characteristics. The combination allows the wafer to be protected during harsh processing steps, yet enables easy separation when needed, resolving the contradiction between protection and ease of separation.
Solution Approach 2:
The bonding material is segmented into two functional layers: the thermoplastic layer handles mechanical protection and initial bonding, while the thermosetting layer handles thermal stability and controlled separation. This segmentation allows each layer to optimize its specific function without compromising the other, resolving the contradiction between protection and separability.
4Ease of operation
If bonding material is cleaned easily, then debonding process simplifies, but adhesion strength under harsh conditions deteriorates
Solution Approach 1:
The thermoplastic layer provides easy cleaning and debonding characteristics, while the thermosetting layer ensures strong adhesion under harsh conditions. This composite structure resolves the contradiction by assigning different functional priorities to each layer, achieving both ease of cleaning and adhesion stability.
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
The dual-layer bonding method provides improved adhesion strength and thermal stability, allowing the bonded wafers to withstand harsh processing conditions without delamination, while also being compatible with laser debonding and easy to clean.
Implementation Method 1
at least one of the first and second bonding layers comprises a bond line adhesion promoter that is covalently bonded with a component present in the other of the first and second bonding layers
Implementation Method 2
a first bonding composition with a thermoplastic material and a second bonding composition that is thermosetting
Data Source
AI summary
A dual-layer temporary bonding system for semiconductor manufacturing including first and second bonding layers is provided. The first bonding layer includes a bond line adhesion promoter that acts as a bond line adhesion promoter during the bonding process. The second bonding layer includes one or more functionalities that will react with the bond line adhesion promoter during the bonding process. The materials and methods of this system can provide increased, precisely controlled, bond line adhesion while at the same time also satisfying other desired performance criteria.