Conductive Seal Prevents Die-Edge Shorting
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Solution Overview
Problem
Existing pressure sensors face issues with die-edge shorting due to manufacturing tolerances, leading to intermittent sensor output and potential malfunction, and current seal designs often result in poorly formed parts that fail to meet dimensional specifications.
Innovation Solution
A conductive seal with a central opening and conductive elements positioned away from the edges, surrounded by an elastomeric insulator, which is injection molded to ensure effective electrical contact and prevent die-edge shorting, while allowing for assembly in various orientations and improved dimensional accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pressure sense die is made slightly smaller than the package housing to accommodate manufacturing tolerances, then the die can be fitted into the housing, but the conductive seals may wrap over the edge of the pressure sense die causing die-edge shorting
Solution Approach 1:
An insulating barrier is introduced as an intermediary element between the conductive seal and the pressure sense die edge. This barrier prevents direct contact between the conductive seal and the die edge, eliminating the harmful electrical shorting effect while allowing the die to remain slightly smaller than the housing for tolerance accommodation.
Solution Approach 2:
The conductive seal design incorporates features that preemptively prevent wrapping over the die edge. By designing the seal with controlled compression characteristics and positioning features, the seal is prevented from reaching the die edge in the first place, counteracting the potential harmful effect before it can occur.
2Ease of manufacture
If traditional bonding and punching operations are used to construct seal designs, then assembly is simplified, but the parts are poorly formed and fail to meet dimensional specifications
Solution Approach 1:
Multiple manufacturing operations (bonding, punching, slicing) are merged into a single injection molding operation. This consolidation eliminates the sequential steps that previously caused dimensional inaccuracies, while maintaining the simplicity of assembly by producing the complete seal assembly in one piece.
Solution Approach 2:
The manufacturing process transitions from discrete mechanical operations (bonding, punching) to a thermal-forming process (injection molding). This parameter change in the manufacturing method enables precise dimensional control while simplifying the overall manufacturing workflow.
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 solution prevents die-edge shorting, ensuring long-term reliability and performance by maintaining electrical insulation and meeting dimensional tolerances, thus enhancing the operational stability and accuracy of pressure sensors.
Implementation Method 1
Each of the conductive elements should be surrounded by an elastomeric insulator
Implementation Method 2
The conductive seals can be compressed against the sense die in order to construct a pneumatic seal and effective electrical connection
Data Source
AI summary
A conductive seal comprises a central opening that can be disposed proximate to a lower surface of a diaphragm in a pressure sense die. A set of electrically conductive elements can be disposed directly over electrically conductive bonding pads on the pressure sense die in such a manner that a number of electrically molded leads can be in electrical contact with the pressure sense die. A set of electrically insulating elements can be placed adjacent to the conductive elements. The conductive elements can be located away from edges of the conductive seal, towards the central opening of the conductive seal without minimizing the insulation between the central opening and the conductive elements of the seal. Therefore, the conductive seal can prevent the pressure sense die and other electrical circuitry from die-edge shorting in order to achieve long-term sensor reliability and performance.