Polyimide Adhesion Layer for Semiconductor Wafer Grinding
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Solution Overview
Problem
Conventional polyimide adhesion layers in semiconductor manufacturing are prone to air bubble formation, leading to reduced adhesiveness and increased risk of semiconductor wafer dropping, cracking, and breaking during grinding, and require high temperatures for bonding due to high glass transition temperatures.
Innovation Solution
A method involving a polyimide layer with a glass transition temperature of 210° C. or less, formed using a polycondensation unit of tetracarboxylic dianhydride and diamine, specifically with aromatic tetracarboxylic dianhydride and diamine structures, which is soluble in solvents, preventing air bubble formation and allowing for low-temperature bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If polyimide is used as an adhesion layer due to its heat resistance, then thermal stability is improved, but solubility in solvents deteriorates making coating difficult
Solution Approach 1:
The patent modifies the chemical structure of polyimide by introducing specific aromatic diamine components with flexible chains, changing the physical parameters of the polymer to achieve both heat resistance and improved solubility in common solvents, enabling coating processability
Solution Approach 2:
The patent creates a composite polyimide structure combining rigid aromatic rings for thermal stability with flexible aliphatic chains for solubility, achieving a material that balances both heat resistance and coating processability
2Strength
If polyamide acid is imidized on support material to form polyimide layer, then adhesion layer is formed, but air bubbles (voids) are easily generated reducing adhesiveness
Solution Approach 1:
The patent performs imidization in advance to form a complete polyimide film before bonding to the support material and semiconductor wafer, eliminating the in-situ imidization process that generates air bubbles and ensuring a void-free adhesion layer
Solution Approach 2:
The patent separates the imidization step from the bonding process, extracting the air bubble generation problem from the adhesion formation process by pre-forming the polyimide layer in a controlled environment
3Stability of the object's composition
If conventional polyimide with high glass transition temperature is used, then heat resistance is improved, but bonding temperature must be raised to 250°C or more increasing energy consumption
Solution Approach 1:
The patent adjusts the glass transition temperature parameter of polyimide to a specific range (200-300°C) by modifying the chemical structure, enabling bonding at reduced temperatures (150-250°C) while maintaining adequate heat resistance for semiconductor applications
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 enables successful grinding of semiconductor wafers without dropping or cracking and facilitates the production of semiconductor apparatuses with reduced wiring disconnections, utilizing a polyimide layer that maintains high heat resistance and mechanical strength.
Implementation Method 1
polyimide for use in the polyimide layer has a glass transition temperature of 210° C. or less and is dissolvable in a solvent
Implementation Method 2
bonding the support material and a circuit-formed face of a semiconductor wafer with the polyimide layer being interposed therebetween
Implementation Method 3
grinding a non-circuit-formed face of the semiconductor wafer to which the support material is bonded
Data Source
AI summary
The purpose of the present invention is to provide a semiconductor substrate manufacturing method, which prevents detachment of a semiconductor wafer being ground, and which prevents cracking or chipping in a semiconductor substrate obtained. In order to solve the problem, the semiconductor substrate manufacturing method comprises: a polyimide layer forming step of forming a polyimide layer on a support material; a wafer attaching step of affixing the support material and a semiconductor wafer to each other with the polyimide layer disposed therebetween; a wafer grinding step of grinding the semiconductor wafer; a support material peeling step of peeling the support material from the polyimide layer; and a polyimide layer peeling step of peeling the polyimide layer from the semiconductor wafer. The polyimide layer includes polyimide which includes a benzophenone skeleton and an aliphatic structure, wherein an amine equivalent weight is 4000 to 20000.