Semiconductor Adhesive Film Multi-Stage Curing
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Solution Overview
Problem
Existing adhesive compositions for semiconductors face challenges in reducing curing time without compromising reliability, as high curing temperatures can lead to void generation and expansion due to exothermic reactions during die-attach and subsequent thermal processes.
Innovation Solution
An adhesive film with a multi-stage curing process and an imidazole curing accelerator, allowing a stepwise increase in curing rates from 120° C to 180° C, with specific DSC curing rate patterns to minimize void generation and enhance die shear strength, while maintaining reliability through controlled thermal processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If curing temperature is increased to reduce curing time, then productivity is improved, but void generation and expansion occur due to exothermic reactions
Solution Approach 1:
The curing process is divided into multiple stages with progressively increasing temperatures (first stage: lower temperature, second stage: medium temperature, third stage: higher temperature). This segmentation allows controlled curing at each stage, preventing excessive heat buildup and void formation while still achieving complete curing in reduced total time compared to single-stage high-temperature curing.
Solution Approach 2:
The adhesive composition includes a curing accelerator that is activated at lower temperatures in the first curing stage. This preliminary action initiates the curing reaction early at controlled temperatures, preventing the need for immediate high-temperature exposure that would cause rapid exothermic reactions and void formation.
2Productivity
If curing time is reduced from 1 hour to less than 1 hour, then productivity is improved, but reliability may deteriorate
Solution Approach 1:
The invention changes the temperature-time parameters of the curing process by implementing a multi-stage curing schedule with specific temperature ranges and durations. The first stage uses lower temperature (60-100°C) for extended time (30-120 minutes) to ensure reliable bonding, while subsequent stages use higher temperatures for shorter durations to complete curing. This parameter optimization achieves full curing in 1-3 hours total, improving productivity while maintaining reliability through the initial low-temperature prolonged exposure.
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 adhesive film achieves a die shear strength of 1 kgf/chip or more, with void proportions less than 10%, effectively suppressing void expansion and ensuring reliable adhesion and reflow resistance by managing curing rates across multiple thermal stages.
Implementation Method 1
high curing temperatures can lead to void generation and expansion due to exothermic reactions during die-attach and subsequent thermal processes
Implementation Method 2
a multi-stage curing process and an imidazole curing accelerator, allowing a stepwise increase in curing rates from 120° C to 180° C
Data Source
AI summary
An adhesive composition for semiconductors, an adhesive film, and a semiconductor device, wherein, in a curing process including a first stage at a temperature ranging from 120° C. to 130° C. for 1 to 20 minutes, a second stage at a temperature ranging from 140° C. to 150° C. for 1 to 10 minutes, a third stage at a temperature ranging from 160° C. to 180° C. for 30 seconds to 10 minutes, and a fourth stage at a temperature ranging from 160° C. to 180° C. for 10 minutes to 2 hours, the adhesive film has a DSC curing rate in the first stage that is 40% or less of a total curing rate, a DSC curing rate in the fourth stage that is 30% to 60% higher than a DSC curing rate in the third stage, and DSC curing rates in each of the second and third stages that are 5% or more higher than a DSC curing rate of a preceding stage thereof.