Heat-Assisted Die Ejection for Thin Wafer Crack Prevention
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Solution Overview
Problem
The increasing thinness of semiconductor wafers complicates the die ejection process from adhesive layers, leading to higher risks of die cracking and reduced yield due to non-uniform stress distribution and decreased peeling energy release rates in conventional needle-based systems.
Innovation Solution
A heat-assisted die ejection system that uses a heated element to reduce the adhesion strength of the adhesive layer, allowing for faster and more reliable die removal without needles, with a die pick-up device to handle the heated adhesive layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional needle-based die ejection is used, then the process is simple and straightforward, but the risk of die cracking increases and yield decreases due to non-uniform stress distribution
Solution Approach 1:
The patent replaces the conventional mechanical needle-based ejection system with a thermal field-based system. A heated element applies uniform thermal energy to the adhesive layer, causing controlled thermal expansion and reduction in adhesion strength, enabling needle-free die release. This substitution eliminates the mechanical stress concentration and non-uniform stress distribution that cause die cracking in needle-based systems.
Solution Approach 2:
The patent changes the physical state and properties of the adhesive layer by applying heat. The heated element raises the temperature of the adhesive layer, causing thermal expansion and phase changes that reduce the adhesion strength between the adhesive layer and the die. This parameter change (temperature) enables uniform and controlled die release without mechanical contact, thereby preventing die cracking.
2Productivity
If wafers are made thinner to increase integration, then the degree of integration increases, but the die ejection process becomes increasingly difficult and more prone to defects
Solution Approach 1:
The patent replaces mechanical needle penetration with thermal field action. The heated element applies uniform thermal energy to the adhesive layer supporting thin dies, causing controlled thermal expansion and adhesion reduction. This thermal approach avoids the mechanical stress concentration that plagues thin die ejection, enabling defect-free release even for ultra-thin dies with high integration.
Solution Approach 2:
The patent utilizes temperature as a control parameter to modify the adhesive layer's properties. By heating the adhesive layer to a controlled temperature, the adhesion strength is reduced uniformly across the entire die surface, enabling safe ejection of thin, highly integrated dies without causing stress-induced cracking or other ejection defects.
3Productivity
If conventional needle ejection is used, then the equipment is simple, but the ejection time is longer and yield is reduced due to die damage
Solution Approach 1:
The patent replaces sequential mechanical needle penetration with parallel thermal field application. The heated element can simultaneously treat multiple adhesive layers across the entire wafer surface, enabling parallel processing and faster ejection cycles. The uniform thermal action releases all dies simultaneously without the sequential mechanical contact that limits speed and causes damage, thereby improving both productivity and yield.
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 system reduces the risk of die cracking and enables efficient ejection of thinner dies in a shorter time, achieving higher yield and minimizing damage to the dies.
Implementation Method 1
a heated element configured to heat an adhesive layer on a bottom side of the adhesive layer
Data Source
AI summary
The present disclosure is directed to die ejection system including a heated element configured to heat an adhesive layer on a bottom side of the adhesive layer, wherein a die is placed on the top side of the adhesive layer, and the die is removed from the adhesive layer by heat-assisted means. A conventional needle-based die ejector system may also be converted into the present die ejection system using a retrofit process.