Reconstructed Package Substrate Blocks for Low-Warpage Fan-Out Packaging
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Solution Overview
Problem
Conventional package substrate packaging processes face challenges with warpage and yield loss due to the large size of package substrates, which limits the number of layers that can be incorporated without causing structural issues.
Innovation Solution
The process involves singulating a package substrate strip into discrete substrate blocks, encapsulating them in an encapsulant, forming a fan-out redistribution structure, and bonding device dies over the reconstructed package substrate, thereby reducing warpage and increasing layer density without yield loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the package substrate size is increased to accommodate more device dies, then the packaging capacity is improved, but warpage and yield loss increase due to structural instability
Solution Approach 1:
The package substrate is divided into multiple substrate blocks that are processed and assembled separately. Each substrate block maintains structural stability while the overall package capacity is increased by combining multiple blocks, thus resolving the contradiction between packaging capacity and structural stability.
Solution Approach 2:
The package structure transitions from a single-plane substrate to a multi-layer stacked architecture with substrate blocks arranged in vertical layers. This dimensional change allows increased packaging capacity without compromising the structural integrity of individual substrate blocks.
2Device complexity
If the package substrate size is increased to fit more layers, then the layer density is improved, but warpage occurs due to large substrate dimensions
Solution Approach 1:
The substrate is segmented into smaller substrate blocks that can support more layers without experiencing warpage. Each block's reduced dimensions maintain structural stability while the overall package achieves higher layer density through vertical stacking of multiple blocks.
Solution Approach 2:
The package architecture moves from horizontal expansion to vertical stacking, organizing substrate blocks in multiple layers. This enables increased layer density while each individual block maintains a manageable size that prevents warpage.
3Ease of manufacture
If conventional packaging processes are used with large substrates, then the manufacturing process is simple, but yield loss increases due to warpage
Solution Approach 1:
The manufacturing process is segmented into modular steps: substrate block fabrication, encapsulation, and assembly. Each module can be optimized independently, maintaining ease of manufacture while improving yield through reduced warpage in smaller substrate blocks.
Solution Approach 2:
Substrate blocks are pre-fabricated and encapsulated with molding compound before final assembly. This preliminary action stabilizes the substrate structure early in the process, preventing warpage-related yield loss in subsequent manufacturing steps while maintaining overall process simplicity.
Data Source
AI summary
A method includes forming a reconstructed package substrate, which includes placing a plurality of substrate blocks over a carrier, encapsulating the plurality of substrate blocks in an encapsulant, planarizing the encapsulant and the plurality of substrate blocks to reveal redistribution lines in the plurality of substrate blocks, and forming a redistribution structure overlapping both of the plurality of substrate blocks and encapsulant. A package component is bonded over the reconstructed package substrate.