Package Alignment Mark Structure for Low-Cost PoP Bonding
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Solution Overview
Problem
In the packaging of semiconductor chips, achieving accurate alignment without increasing manufacturing costs is challenging, especially with the complexity introduced by Package-on-Package (PoP) technology, where multiple packages need to be bonded for enhanced integration and reduced electrical path lengths.
Innovation Solution
The integration of through-vias and alignment marks within the molding material, where the alignment marks penetrate through the molding material and are used to accurately position the device die, while the through-vias provide electrical coupling, allowing for precise alignment without additional manufacturing steps or costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional alignment methods are used for Package-on-Package bonding, then manufacturing cost is controlled, but alignment accuracy deteriorates due to the complexity of multiple packages
Solution Approach 1:
The patent combines the alignment mark structure with the through-via structure, creating a unified feature that serves both alignment and electrical connection functions. This merging eliminates the need for separate alignment marks, thereby improving alignment accuracy without adding manufacturing complexity or cost.
Solution Approach 2:
The through-via structure is designed to perform multiple functions: providing electrical connection between packages and serving as an alignment mark for precise positioning. This multi-functionality resolves the contradiction by eliminating dedicated alignment features while maintaining alignment accuracy through the functional integration into existing structural elements.
2Manufacturing precision
If separate alignment marks are added to improve alignment accuracy, then alignment precision is improved, but manufacturing cost increases
Solution Approach 1:
The alignment mark functionality is merged into the through-via structure, eliminating the need for separate alignment mark fabrication steps. This integration maintains alignment accuracy while avoiding additional manufacturing processes, materials, and costs associated with traditional separate alignment marks.
Solution Approach 2:
The through-via structure serves dual purposes: electrical connection and alignment reference. By making the through-via structure itself serve as the alignment mark, the patent eliminates redundant manufacturing steps and reduces overall manufacturing cost while maintaining precise alignment capability.
3Reliability
If Package-on-Package technology is implemented to enhance integration, then electrical performance is improved, but alignment complexity increases
Solution Approach 1:
The patent merges alignment and electrical connection functions into a single through-via structure, simplifying the alignment process for PoP packages. This integration reduces alignment complexity by eliminating the need to locate and align with separate alignment marks on each package layer, while maintaining the electrical performance benefits of PoP technology.
Solution Approach 2:
The through-via structure performs multiple functions including electrical connection and alignment reference for multiple package layers. This multi-functionality reduces alignment complexity by providing inherent alignment features within the electrical connection structure itself, eliminating the need for additional alignment procedures in multi-package stacking.
Data Source
AI summary
A package includes a device die, a molding material molding the device die therein, a through-via penetrating through the molding material, and an alignment mark penetrating through the molding material. A redistribution line is on a side of the molding material. The redistribution line is electrically coupled to the through-via.