Packaged IC Raised Test Points via Molded Recess
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Solution Overview
Problem
Existing packaging techniques for integrated circuits, such as molded plastic lids, do not allow easy access to test points without damaging the IC, as they lack the removability of metal lids and pose challenges in controlling depth and position during milling for exposing test points.
Innovation Solution
A test point standoff is electrically connected to the IC die and extends through the molded plastic lid, with a recess formed in the lid to expose the standoff for electrical testing, ensuring protection against damage and inadvertent shorting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a molded plastic lid is used to encapsulate the IC, then protection against damage and environmental factors is improved, but access to test points becomes difficult and risks damaging the IC
Solution Approach 1:
The patent divides the lid into two functional segments: a molded plastic lid providing protection, and a separately formed recess providing access. This segmentation allows the lid to simultaneously offer environmental protection while enabling safe access to test points through the recess, resolving the contradiction between protection and accessibility.
Solution Approach 2:
The recess acts as an intermediary structure between the protective molded lid and the test points. It provides a controlled access path that allows testing equipment to reach the test points without compromising the overall protective function of the molded lid, thus resolving the access difficulty while maintaining protection.
2Ease of operation
If milling is used to expose test points through the molded lid, then access to test points is achieved, but control of depth and position is difficult risking damage to the IC
Solution Approach 1:
The recess is pre-formed in the molded lid during the molding process itself, before any testing operations occur. This preliminary action eliminates the need for subsequent milling operations, ensuring precise depth and position control without risking damage to the IC, as the access path is already precisely defined by the mold geometry.
Solution Approach 2:
The patent replaces the mechanical milling process with a molded recess structure. Instead of using milling equipment to create the access path, the recess is formed during molding, substituting a precise chemical/molding process for a less controllable mechanical removal process, thereby improving depth and position control.
3Ease of operation
If test points are exposed on the surface, then access for testing is improved, but protection against shorting and static discharge is reduced
Solution Approach 1:
The recess is nested within the molded lid structure, creating a hierarchical arrangement where the test points remain enclosed within the protective lid while still being accessible. The recessed test points are protected by the surrounding lid material, which shields them from static discharge and shorting risks while allowing controlled access for testing equipment.
Solution Approach 2:
The patent applies different properties to different parts of the lid: the majority of the lid surface provides continuous protection, while the localized recess area provides controlled access. This local quality differentiation allows the test points in the recess to be accessible while the surrounding lid material continues to provide protection against harmful factors like static discharge and shorting.
Data Source
AI summary
A packaged integrated circuit (“IC”) includes a substrate, an IC die, and a molded plastic lid. A test point standoff is electrically connected to the IC die and extends away from the surface of the package substrate through the molded plastic lid toward the top surface of the molded plastic lid. The top of the test point standoff is below the top surface of the molded plastic lid.