Cushioning Sheet for Uniform Semiconductor Sinter Bonding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In semiconductor device manufacturing, batch sinter bonding using a hot press machine often results in bonding failures due to non-uniform load distribution and precision issues with parallel plates, leading to incomplete bonding at the outer edges of sintered layers.
Innovation Solution
A semiconductor device manufacturing method that employs a cushioning sheet with a thickness of 5 to 5000 μm and a tensile elastic modulus of 2 to 150 MPa, placed over the sinter-bonding work, to absorb deviations and ensure uniform pressure during the sinter bonding process, thereby preventing bonding failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If batch sinter bonding is performed using a hot press machine with parallel plates, then productivity is improved by bonding multiple chips simultaneously, but manufacturing precision deteriorates due to non-uniform load distribution causing bonding failures at outer edges
Solution Approach 1:
A cushioning sheet is introduced as an intermediary element between the upper pressing plate and the sinter-bonding material layers. This cushioning sheet absorbs load non-uniformities and ensures uniform pressure distribution across all sinter-bonding material layers during the sinter bonding process, thereby preventing bonding failures while maintaining batch processing capability
Solution Approach 2:
The cushioning sheet is designed with specific physical parameters (thickness of 5 to 5000 μm and tensile elastic modulus of 2 to 150 MPa) that enable it to deform and absorb pressure variations. By carefully selecting these parameters, the system transforms the rigid pressing mechanism into a more compliant system that can accommodate variations in workpiece thickness and positioning
2Length of moving object
If the thickness of semiconductor chips and sinter-bonding material layers is reduced to several micrometers to several hundreds of micrometers, then device miniaturization is achieved, but manufacturing precision deteriorates due to sensitivity to parallel plate positioning errors
Solution Approach 1:
The cushioning sheet is placed beforehand over the sinter-bonding work before the sinter bonding process begins. This pre-positioned cushioning layer anticipates and compensates for potential positioning errors and thickness variations, ensuring that even thin workpieces receive uniform pressure throughout the bonding process
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 method achieves high uniformity in pressure distribution, eliminating bonding failures and ensuring reliable sinter bonding of semiconductor chips to substrates, even in high-temperature operations, by effectively absorbing deviations in the parallel plates and maintaining shape retainability.
Implementation Method 1
a cushioning sheet having a thickness of 5 to 5000 μm and a tensile elastic modulus of 2 to 150 MPa
Implementation Method 2
a sintering process operates under predetermined temperature and pressurization conditions so that the solvent in the sinter-bonding material undergoes, for example, volatilization and the sintering proceeds between the sinterable particles
Data Source
AI summary
A semiconductor device manufacturing method includes a preparation step and a sinter bonding step. In the preparation step, a sinter-bonding work having a multilayer structure including a substrate, semiconductor chips, and sinter-bonding material layers is prepared. The semiconductor chips are disposed on, and will bond to, one side of the substrate. Each sinter-bonding material layer contains sinterable particles and is disposed between each semiconductor chip and the substrate. In the sinter bonding step, a cushioning sheet having a thickness of 5 to 5000 μm and a tensile elastic modulus of 2 to 150 MPa is placed on the sinter-bonding work, the resulting stack is held between a pair of pressing faces, and, in this state, the sinter-bonding work between the pressing faces undergoes a heating process while being pressurized in its lamination direction, to form a sintered layer from each sinter-bonding material layer.