Package on Package Structure with Conductive Posts
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Solution Overview
Problem
Existing package on package structures require filling and solidifying conductive paste in receiving holes to establish electrical connections, which can lead to bubble formation and increased manufacturing complexity and cost.
Innovation Solution
The method involves a connection substrate with electrically conductive posts protruding through its surfaces, allowing direct attachment of package devices without the need for filling conductive material, using an epoxy molding compound layer and grinding to expose post ends for soldering, thereby eliminating the need for conductive paste and simplifying the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conductive paste is filled and solidified in receiving holes to establish electrical connections, then electrical connectivity between packages is achieved, but bubble formation occurs and manufacturing complexity increases
Solution Approach 1:
The patent extracts and eliminates the conductive paste filling step from the manufacturing process. Instead of filling receiving holes with conductive paste that requires solidification, the invention uses pre-formed conductive posts that are directly attached to the lower package, thereby removing the source of bubble formation while maintaining electrical connectivity.
Solution Approach 2:
The conductive posts are prepared and attached to the lower package in advance, before the upper package is positioned. This preliminary action allows the posts to be pre-aligned and pre-soldered, eliminating the need for subsequent paste filling and solidification steps that cause bubbles and manufacturing delays.
2Reliability
If conductive paste filling and solidification is performed, then electrical connections are established, but manufacturing complexity and cost increase
Solution Approach 1:
The patent removes the complex multi-step process of conductive paste application, positioning, and solidification from the manufacturing workflow. By using pre-attached conductive posts, the process is simplified to direct alignment and attachment of the upper package, significantly reducing manufacturing complexity and cost.
Solution Approach 2:
The conductive posts are designed to be self-contained and pre-mounted components that provide their own electrical connection functionality. This eliminates the need for the manufacturing system to perform paste filling and solidification operations, allowing for a more streamlined and cost-effective manufacturing process.
3Reliability
If conductive paste is used for electrical connections, then connectivity is achieved, but production rate decreases due to filling and solidification time
Solution Approach 1:
The conductive posts are attached to the lower package in a preliminary step before final assembly. This allows the time-consuming paste filling and solidification process to be performed in advance on stationary components, rather than during the final assembly operation, thereby significantly increasing the production rate of the package-on-package structure.
Data Source
AI summary
A package on package structure includes a connection substrate having a main body and electrically conductive posts, the main body includes a first surface and an opposite second surface, and each electrically conductive post passes through the first and second surfaces, and each end of the two ends of the electrically conductive post protrudes from the main body; a first package device arranged on a side of the first surface of the connection substrate; a package adhesive arranged on a side of the second surface of the connection substrate; and a second package device arranged on a side of the package adhesive furthest away from the first package device.