Side Vented Pressure Sensor Gel Encapsulation
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Solution Overview
Problem
Conventional semiconductor pressure sensor devices have high manufacturing costs due to the use of pre-molded lead frames, metal lids, and large volumes of pressure-sensitive gel material, and they face challenges in full encapsulation without impeding functionality.
Innovation Solution
A semiconductor sensor device design featuring a substrate with a pressure sensing die and other dies electrically interconnected, covered with pressure-sensitive gel material, and encapsulated with a cap having a side vent hole formed during the singulation process, reducing manufacturing steps and costs while protecting the dies from mechanical and environmental damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pre-molded lead frame with metal lid and large volume pressure sensitive gel material is used, then the dies are protected from mechanical and environmental damage, but the manufacturing cost increases
Solution Approach 1:
The patent removes the pre-molded lead frame and metal lid from the packaging structure, retaining only the essential protective functions through alternative means (mold compound and gel material application), thereby eliminating unnecessary components and reducing manufacturing complexity and cost
Solution Approach 2:
The patent applies gel material selectively only where pressure sensing is required (on the active region of the die) rather than using large volumes throughout the entire package, optimizing material usage and reducing overall material costs while maintaining protective functionality
2Ease of operation
If a metal lid with vent hole is used, then ambient atmospheric pressure reaches the pressure sensitive active region, but the manufacturing complexity increases
Solution Approach 1:
The patent eliminates the metal lid component entirely, integrating the venting function directly into the mold compound structure through side vents formed during molding, thereby simplifying the manufacturing process by removing a separate component and assembly step
Solution Approach 2:
The patent combines the protective enclosure function and the pressure venting function into a single integrated mold compound structure, where the side vents are formed as part of the molding process itself, eliminating the need for separate lid fabrication and assembly operations
3Reliability
If a pre-molded lead frame structure is used, then the dies are properly positioned and protected, but the manufacturing cost and process complexity increase
Solution Approach 1:
The patent removes the pre-molded lead frame from the packaging structure, using alternative methods (mold compound encapsulation and die attach materials) to achieve proper die positioning and protection, thereby simplifying the overall packaging process and reducing manufacturing steps
Solution Approach 2:
The mold compound serves multiple functions simultaneously: it provides mechanical protection for the dies, establishes proper positioning through the molding cavity geometry, and creates integrated side vents for pressure equalization, eliminating the need for separate lead frame and lid components
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
The design reduces manufacturing costs and susceptibility to clogging, enabling efficient and cost-effective production of semiconductor sensor devices with improved protection and functionality.
Implementation Method 1
pressure sensitive gel material covering an active region of the pressure sensing die... enables the pressure of the ambient atmosphere to reach the pressure sensitive active region
Implementation Method 2
the cap has a side vent hole formed thereon that exposes the gel covered active region of the pressure sensing die to ambient atmospheric pressure outside the sensor device
Data Source
AI summary
A semiconductor sensor device has a pressure sensing die and at least one other die mounted on a substrate, and electrical interconnections that interconnect the pressure sensing die and the at least one other die. An active region of the pressure sensing die is covered with a pressure sensitive gel material, and a cap having a cavity is mounted over the pressure sensing die such that the pressure sensing die is positioned within the cavity. The cap has a side vent hole that exposes the gel covered active region of the pressure sensing die to ambient atmospheric pressure outside the sensor device. Molding compound on an upper surface of the substrate encapsulates the at least one other die and at least a portion of the cap.