Die Caves in Semiconductor Packaging for Alignment
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Solution Overview
Problem
Semiconductor devices experience undesirable die movement during wafer level packaging, leading to alignment issues and reduced yields, particularly in multi-chip packages.
Innovation Solution
A die cave material is formed over a carrier wafer, patterned with die caves to securely hold semiconductor dies in place, preventing movement during molding compound deposition and subsequent processing steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If die are positioned on carrier wafers during wafer level packaging, then semiconductor devices can be packaged in smaller packages with redistribution layers, but die movement occurs causing alignment issues and reduced yields
Solution Approach 1:
The patent applies preliminary action by forming a molding compound layer before die placement, then creating cavities in this pre-formed layer to receive the die. This preliminary formation of the molding compound with integrated cavities prevents die movement during subsequent packaging steps, resolving the alignment precision issue while maintaining the compact WLP structure
Solution Approach 2:
The patent implements nesting by placing die within cavities that are nested within the molding compound layer. The die are positioned inside recesses formed in the molding material, creating a nested structure where the die are embedded within the package substrate, preventing movement and ensuring precise alignment for redistribution layer formation
2Ease of manufacture
If molding compound is formed over die in conventional WLP, then package structure is completed, but die rotation and shifting occur during the process
Solution Approach 1:
The molding compound with cavities is formed before die placement, establishing the die positions and preventing movement during the remainder of the packaging process. This preliminary structuring maintains die stability while preserving manufacturing simplicity
Solution Approach 2:
The molding compound acts as an intermediary material that provides both structural support and position stabilization for the die. The cavities in the molding compound serve as intermediaries that physically constrain die movement while allowing the die to be held securely during package formation
3Manufacturing precision
If die are held in place during WLP processing, then alignment precision is improved, but additional process steps are required
Solution Approach 1:
The patent merges the die retention function with the molding compound formation step. The cavities are created as part of the molding compound processing, combining the structural formation and die positioning functions into a single integrated process rather than adding separate retention mechanisms
Solution Approach 2:
The molding compound serves multiple functions: it provides mechanical support, creates position-stabilizing cavities, and enables subsequent redistribution layer formation. This multi-functionality achieves precise die alignment without requiring dedicated retention structures or additional process steps
Data Source
AI summary
Methods of packaging semiconductor devices and structures thereof are disclosed. In one embodiment, a method of packaging a semiconductor device includes providing a carrier wafer, providing a plurality of dies, and forming a die cave material over the carrier wafer. A plurality of die caves is formed in the die cave material. At least one of the plurality of dies is placed within each of the plurality of die caves in the die cave material. A plurality of packages is formed, each of the plurality of packages being formed over a respective at least one of the plurality of dies.