Multi-layer adhesive bonding for semiconductor wafer processing
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Solution Overview
Problem
Conventional adhesives used in semiconductor wafer processing outgas volatile organic compounds (VOCs) at temperatures encountered during metallization, leading to poor metal adhesion and contamination of the process chamber.
Innovation Solution
A multi-layered contact layer is formed on the semiconductor wafer, comprising a first adhesive layer with a lower outgassing temperature and a second layer with a higher outgassing temperature, which covers the first layer to prevent outgassing and contamination, and is designed for secure bonding and easy de-bonding using a perforated carrier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional adhesive is used to bond the semiconductor wafer to the wafer carrier, then the wafer can be securely attached for processing, but the adhesive outgasses VOCs at metallization temperatures causing poor metal adhesion and chamber contamination
Solution Approach 1:
The contact layer is divided into multiple layers: a first adhesive layer (e.g., polyimide) that provides strong bonding at lower temperatures, and a second adhesive layer with higher thermal stability that prevents VOC outgassing during metallization. This segmentation allows each layer to perform its specific function without interfering with the other.
Solution Approach 2:
The contact layer uses a composite structure combining different adhesive materials with complementary properties. The first layer provides initial bonding strength, while the second layer contributes thermal stability and VOC resistance. Together they create a composite contact layer that satisfies both bonding strength and outgassing resistance requirements.
2Ease of manufacture
If the adhesive is coated on the front side of the wafer for bonding, then the wafer can be easily attached to the carrier, but the adhesive outgassing during metallization causes peeling of the metal layer
Solution Approach 1:
The contact layer is segmented into multiple functional layers: the first adhesive layer enables easy wafer attachment to the carrier, while the second thermally stable adhesive layer protects against VOC outgassing during metallization, ensuring reliable metal layer adhesion throughout subsequent processing.
Solution Approach 2:
The multi-layer adhesive structure is prepared in advance before metallization, with the thermally stable second layer already in place to prevent VOC outgassing. This preliminary protective action ensures that when metallization occurs, the adhesive does not outgas and compromise metal layer adhesion.
3Strength
If a solid wafer carrier is used for bonding, then the wafer is securely held, but de-bonding becomes difficult without damaging the wafer
Solution Approach 1:
The wafer carrier is designed with a porous or perforated structure that allows solvents to penetrate through to the adhesive layers. This porosity enables controlled de-bonding by allowing solvent to reach and dissolve the adhesive, facilitating easy separation of the wafer from the carrier without damage.
Solution Approach 2:
A solvent acts as an intermediary substance that penetrates the porous carrier structure to reach and dissolve the adhesive layers. This intermediary enables the de-bonding process by chemically breaking down the adhesive bonds without requiring mechanical force that could damage the wafer.
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 multi-layered contact layer effectively reduces VOC outgassing and contamination, ensuring better metal adhesion and ease of carrier removal, while allowing for a variety of adhesive materials to be used, thereby improving the semiconductor wafer processing outcomes.
Implementation Method 1
temperatures in the metal deposition tool chamber, as well as on the semiconductor wafer itself, may exceed the temperature at which commonly used adhesives begin to outgas volatile organic compounds
Implementation Method 2
The semiconductor wafer is attached to the wafer carrier using an adhesive that is coated and cured on the semiconductor wafer
Data Source
AI summary
The embodiments of the present invention relate to semiconductor device manufacturing, and more particularly, a method of temporarily bonding a semiconductor wafer to a wafer carrier with a multi-layered contact layer as well as a structure. A method is disclosed that includes: forming a first layer on a surface of a semiconductor wafer; forming a second layer on the first layer; bonding a perforated carrier to the second layer; and removing the semiconductor wafer from the perforated carrier. The first layer may be composed of an adhesive. The second layer may be composed of a material having a higher outgassing temperature than the first layer.