Semiconductor Die Bonding with Two-Stage Cure to Limit Filler Sinking
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Solution Overview
Problem
The integration of a conductive filler in the adhesive material between the back surface electrode of a semiconductor chip and the die pad leads to increased electric and thermal resistance, degrading the performance of the semiconductor device.
Innovation Solution
A two-stage heat treatment process is employed, where the first adhesive material is cured with a shorter duration followed by a second cure, ensuring proper adhesion and reducing filler sinking, thereby maintaining low resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conductive paste type adhesive material is used for die bonding, then electrical connection is achieved, but conductive filler sinks during curing causing increased electric resistance and thermal resistance
Solution Approach 1:
The patent applies preliminary action by performing a first heat treatment to cure the adhesive material before the conductive filler can sink during subsequent curing. This preliminary curing stabilizes the adhesive structure, preventing filler settlement and maintaining uniform distribution throughout the bonding layer, thereby resolving the contradiction between achieving electrical connection and maintaining filler uniformity
Solution Approach 2:
The patent changes the curing parameter sequence by implementing two-stage heat treatment with different temperature profiles. The first heat treatment occurs at a controlled temperature to cure the adhesive before filler sinking, while the second heat treatment completes the curing process. This parameter change prevents filler settlement while ensuring complete adhesive curing, thus maintaining both electrical connection quality and filler distribution uniformity
2Strength
If heat treatment time is extended to ensure complete curing, then adhesive strength improves, but manufacturing time increases reducing productivity
Solution Approach 1:
The patent segments the heat treatment process into two distinct stages: a first heat treatment that cures the adhesive material to prevent filler sinking, and a second heat treatment that completes the curing process. This segmentation allows each stage to be optimized independently - the first stage ensures filler stability while the second stage achieves complete curing - thereby maintaining adhesive strength while reducing total manufacturing time and improving productivity
Solution Approach 2:
The first heat treatment serves as a preliminary action that partially cures the adhesive material before the full curing process. This preliminary curing establishes the structural framework needed to prevent filler sinking, allowing the subsequent second heat treatment to focus on completing the curing without worrying about filler settlement. This approach achieves complete curing with optimized time allocation, improving both strength and productivity
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 method improves the semiconductor device's performance by minimizing electric and thermal resistance, enhancing overall functionality.
Implementation Method 1
performing a first heat treatment for curing the first adhesive material
Implementation Method 2
conductive filler contained in the adhesive material sinks in the conductive paste type adhesive material
Data Source
AI summary
To manufacture a semiconductor device, a first heat treatment for curing a first adhesive material of a conductive paste type is performed, after a semiconductor chip is mounted on a die pad of a lead frame via the first adhesive material. After that, a metal plate is disposed on a pad of the semiconductor chip such that the metal plate faces the pad of the semiconductor chip via a second adhesive material of a conductive paste type, and a second heat treatment is performed for curing each of the first adhesive material and the second adhesive material. A time of the first heat treatment is less than a time of the second heat treatment. After the first adhesive material is cured by the first heat treatment, the first adhesive material is further cured by the second heat treatment.