Semiconductor Die Buffer Material for Crack Prevention
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Solution Overview
Problem
As semiconductor devices are miniaturized and integrated into smaller volumes, challenges arise in bonding and operation due to differences in material properties such as Young's modulus and coefficient of thermal expansion, leading to issues like cracks and reduced reliability.
Innovation Solution
A buffer material with intermediate properties between the semiconductor die and underfill material is dispensed around the edges and corners of the semiconductor dies, acting as a buffer to mitigate thermal expansion differences and facilitate bonding, using a process that involves singulation and curing to ensure alignment and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If semiconductor devices are miniaturized to improve integration density, then more components can be integrated into a given volume, but cracks and reduced reliability occur due to differences in material properties
Solution Approach 1:
A buffer material with intermediate properties (Young's modulus and coefficient of thermal expansion) is introduced between the semiconductor die and underfill material. This intermediary layer mitigates the harmful effects of material property mismatches, preventing cracks while allowing continued miniaturization for high integration density.
Solution Approach 2:
The buffer material has deliberately selected intermediate physical parameters (Young's modulus and coefficient of thermal expansion) that are between those of the semiconductor die and underfill material. By changing the material parameters to intermediate values, the system resolves the contradiction between miniaturization benefits and reliability concerns.
2Reliability
If buffer material is dispensed around the edges and corners of semiconductor dies to mitigate thermal expansion differences, then reliability is improved, but the manufacturing process complexity increases
Solution Approach 1:
The buffer material is dispensed and cured on the semiconductor die before the underfill material is applied. This preliminary action ensures proper alignment and positioning, simplifying the subsequent underfill application process and improving bonding reliability without excessive complexity.
Solution Approach 2:
The buffer material is selectively dispensed around the edges and corners of the semiconductor die where thermal expansion stresses are most concentrated. This localized application addresses the critical stress points without requiring complete coverage, reducing manufacturing complexity while maintaining reliability improvements.
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 buffer material effectively reduces the occurrence of cracks, enhancing the yield and reliability of semiconductor devices by bridging the thermal expansion gap between the semiconductor die and underfill, thereby improving the chip on wafer on substrate configuration.
Implementation Method 1
differences in material properties such as Young's modulus and coefficient of thermal expansion, leading to issues like cracks and reduced reliability
Data Source
AI summary
In order to prevent cracks from occurring at the corners of semiconductor dies after the semiconductor dies have been bonded to other substrates, an opening is formed adjacent to the corners of the semiconductor dies, and the openings are filled and overfilled with a buffer material that has physical properties that are between the physical properties of the semiconductor die and an underfill material that is placed adjacent to the buffer material.