Semiconductor Package Heat Spreader Direct Die Attachment
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Solution Overview
Problem
Current fan-out semiconductor packages with heat spreaders have inefficient heat dissipation due to the heat being transferred through molding material, and the protective layer removal process for conductive traces is time-consuming using laser drilling.
Innovation Solution
A manufacturing method involving a redistribution layer with chemical or plasma etching to expose conductive traces, allowing for quicker removal of the protective layer and improved heat dissipation by direct attachment of the heat spreader to the die using a thermal interface material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If laser drilling is used to remove the protective layer on the redistribution layer, then the protective layer can be removed, but the process takes a long time especially when high cleaning demand is required
Solution Approach 1:
The patent replaces the mechanical laser drilling process with a chemical etching process using fluorine-based plasma. This substitution fundamentally changes the removal mechanism from mechanical ablation to chemical reaction, achieving both faster processing time and complete protective layer removal without the time-consuming limitations of laser drilling.
Solution Approach 2:
The patent changes the etching parameters by using fluorine-based plasma chemistry instead of laser energy. The fluorine plasma reacts chemically with the protective layer materials (organic and inorganic), enabling rapid and complete removal. The process parameters include fluorine concentration, plasma power, and exposure time, which can be optimized for different protective layer compositions.
2Temperature
If the heat spreader is attached to the molding material that seals the die, then the package structure is formed, but the heat dissipation efficiency is reduced because heat must be transferred through the molding material first
Solution Approach 1:
The patent extracts the heat spreader from its conventional position attached to the molding material and repositions it to attach directly to the die. This extraction removes the thermal resistance barrier (molding material) from the heat dissipation path, allowing heat to flow directly from the die to the heat spreader without being impeded by the molding compound.
Solution Approach 2:
The patent changes the dimensional relationship between the heat spreader and die by eliminating the intermediate molding material layer. This creates a direct thermal interface in the vertical dimension, reducing thermal resistance and improving heat dissipation efficiency while maintaining the overall package structure.
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
Enhances heat dissipation efficiency and reduces the time required for protective layer removal compared to traditional laser drilling methods.
Implementation Method 1
performing a chemical or plasma etching process on the second surface of the redistribution layer to expose the conductive traces in the redistribution layer
Implementation Method 2
performing a chemical or plasma etching process on the second surface of the redistribution layer to expose the conductive traces in the redistribution layer
Implementation Method 3
The heat spreader is directly attached to the die through the thermal interface material, and the molding layer is formed between the heat spreader and the redistribution layer
Data Source
AI summary
The method of manufacturing a semiconductor package of the present disclosure includes: providing a redistribution layer having opposing first surface and second surface; disposing a die on the first surface of the redistribution layer and electrically connecting the die to the redistribution layer; forming a mask on the second surface of the redistribution layer; performing a chemical or plasma etching process on the second surface of the redistribution layer to expose the conductive traces in the redistribution layer; removing the mask; and forming a plurality of conductive bumps on the second surface of the redistribution layer and electrically connecting the conductive bumps to the exposed conductive traces in the redistribution layer.