Protruding Post Substrate Package for Warpage Control
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Solution Overview
Problem
As BGA packages become smaller and thinner, solder ball registration becomes increasingly difficult, leading to higher costs and reduced reliability, and warpage issues result in defective interconnections with fine pitch solder balls.
Innovation Solution
A method involving a rigid carrier with a dielectric layer and selectively etchable metal, where via apertures and cavities are formed to create protruding posts that provide both structural rigidity and interconnection for the substrate package, allowing for precise formation and mounting on a printed circuit motherboard.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If solder balls are used for BGA package interconnection, then electrical connection is achieved, but as pitch is reduced for smaller packages, registration difficulty increases and reliability decreases
Solution Approach 1:
The patent extracts the interconnection function from traditional solder balls and implements it through protruding posts with spherical tips. The posts are pre-formed on the substrate before component attachment, providing precise positioning and reliable electrical connection without the registration difficulties of fine-pitch solder balls. This extraction of the interconnection mechanism resolves the contradiction between high pitch density and registration reliability.
2Volume of moving object
If BGA package size is reduced for thinner designs, then package thickness is decreased, but warpage increases causing defective interconnections
Solution Approach 1:
The patent applies preliminary action by forming the protruding posts on the substrate before assembling the BGA package. This pre-formation ensures precise positioning and structural stability are established in advance, preventing warpage-related defects during subsequent assembly processes. The preliminary structuring of interconnection elements maintains package flatness even in reduced-thickness designs.
3Manufacturing precision
If fine pitch protruding posts are formed for high-density interconnection, then interconnection precision is improved, but manufacturing complexity increases
Solution Approach 1:
The protruding posts are pre-formed on the substrate using standard semiconductor fabrication techniques before package assembly. This preliminary formation of interconnection structures with precise pitch and positioning simplifies the overall manufacturing process by eliminating the need for complex post-assembly alignment and attachment operations, thereby reducing fabrication complexity while maintaining high precision.
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 ensures the substrate package remains flat and prevents warpage, enabling reliable formation of fine pitch protruding posts for secure electrical and physical mounting, thus improving the reliability and cost-effectiveness of BGA packages.
Implementation Method 1
the carrier cavities are lined with a first metal, the first metal being selectively etchable compared to the carrier
Data Source
AI summary
In accordance with one embodiment, a method of forming a protruding post substrate package includes applying a dielectric layer to a carrier. Via apertures are formed in the dielectric layer. Carrier cavities are formed in the carrier using the dielectric layer as a mask. The carrier cavities are lined with a first metal, the first metal being selectively etchable compared to the carrier. After encapsulation of an electronic component with an encapsulant, the carrier is removed such that protruding posts including the first metal protrude outward from a first surface of the dielectric layer.