Footed Lid Semiconductor Sensor Packaging for Defect Reduction
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Solution Overview
Problem
Current semiconductor sensor device packaging is prone to mechanical and environmental damage, and pre-molded lead frames have issues like low yield, mold defects, and inconsistencies, which increase costs and reduce reliability.
Innovation Solution
A method involving a substrate with die attach areas and electrical connection pads, where semiconductor sensor dies are attached and electrically connected, and a footed lid is used to surround the dies, with a gel material and molding compound encapsulating the assembly to form a cavity, eliminating the need for pre-molded lead frames.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If pre-molded lead frames are used to package sensor dies, then the packaging process is simplified, but manufacturing defects such as mold flashing, voids, and cavity height inconsistency increase
Solution Approach 1:
The patent extracts the pre-molding step from the traditional packaging process. Instead of using pre-molded lead frames with pre-formed cavities, the method applies molding compound directly over the sensor die mounted on a lead frame, eliminating the source of mold-related defects while maintaining packaging simplicity
Solution Approach 2:
The packaging process is segmented into distinct steps: mounting the sensor die on the lead frame, attaching a lid to form a cavity, and then applying molding compound. This segmentation allows each step to be optimized independently, avoiding the compounding defects of pre-molding
2Productivity
If pre-molded lead frames are used to package sensor dies, then the packaging structure is established quickly, but yield and reliability decrease due to mold related defects
Solution Approach 1:
By removing the pre-molding operation from the process, the patent eliminates the primary source of manufacturing defects that reduce yield, while maintaining efficient packaging through the streamlined sequence of die attachment, lid placement, and compound molding
3Object-affected harmful factors
If sensor dies are fully encapsulated, then environmental protection is improved, but functionality is impeded
Solution Approach 1:
The patent applies local quality by providing differential protection: the lid creates a protected cavity for the sensor die while leaving the membrane area accessible for pressure sensing. The molding compound provides environmental protection while the lid structure maintains functional access where needed
Data Source
AI summary
A semiconductor sensor device is packaged using a footed lid instead of a pre-molded lead frame. A semiconductor sensor die is attached to a first side of a lead frame. The die is then electrically connected to leads of the lead frame. A gel material is dispensed onto the sensor die. The footed lid is attached to the substrate such that the footed lid covers the sensor die and the electrical connections between the die and the lead frame. A molding compound is then formed over the substrate and the footed lid such that the molding compound covers the substrate, the sensor die and the footed lid.