Integrated Fan-Out Package Planarization via Elastic Adhesive
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Solution Overview
Problem
The semiconductor industry faces challenges in achieving precise planarization and efficient redistribution circuit formation in integrated fan-out packages due to height variations between different types of dies, which complicates the packaging process and affects the integration density and reliability of the final product.
Innovation Solution
A method involving the use of a de-bonding layer and an elastic polymeric adhesive layer to encapsulate and align conductive posts of different dies, followed by a thinning process to level the dies and form a redistribution structure that electrically connects to the dies, ensuring a smooth surface for subsequent processing and enhancing the reliability of the package.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If dies of different heights are integrated into the package, then integration density and versatility are improved, but planarization difficulty and manufacturing precision deteriorate
Solution Approach 1:
An adhesive layer is introduced as an intermediary substance between the carrier and the dies. This adhesive layer has varying thicknesses that correspond to the height differences of different dies, allowing them to be mounted on the same carrier surface. The adhesive layer compensates for height variations, enabling planarization of the top surfaces of dies with different heights while maintaining their individual height characteristics for electrical connection purposes.
2Ease of manufacture
If conventional planarization methods are used on dies of varying heights, then manufacturing simplicity is maintained, but reliability deteriorates due to under/over-grinding
Solution Approach 1:
The adhesive layer is applied with locally varied thicknesses corresponding to the specific height requirements of different dies. This local quality variation in the adhesive layer thickness allows each die to achieve proper planarization at its specific height, preventing under-grinding (insufficient planarization) or over-grinding (excessive material removal) that would compromise die connection reliability.
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
This approach allows for the efficient integration of different dies with varying heights, improving the planarization and redistribution processes, thereby increasing integration density and reducing the complexity and risk of under/over-grinding, leading to more reliable and compact integrated fan-out packages.
Implementation Method 1
an elastic polymeric adhesive layer to encapsulate and align conductive posts of different dies
Data Source
AI summary
A manufacturing method of integrated fan-out package includes following steps. First and second dies are provided on adhesive layer formed on carrier. Heights of first and second dies are different. First and second dies respectively has first and second conductive posts each having substantially a same height. The dies are pressed against adhesive layer to make active surfaces thereof be in direct contact with adhesive layer and conductive posts thereof be submerged into adhesive layer. Adhesive layer is cured. Encapsulant is formed to encapsulate the dies. Carrier is removed from adhesive layer. Heights of first and second conductive posts are reduced and portions of the adhesive layer is removed. First and second conductive posts are laterally wrapped by and exposed from adhesive layer. Top surfaces of first and second conductive posts are leveled. Redistribution structure is formed over adhesive layer and is electrically connected to first and second conductive posts.