MEMS Pressure Transducer Barrier Structure That Preserves Back Volume
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Solution Overview
Problem
MEMS pressure transducers are vulnerable to environmental substances like aerosols, salt particles, moisture, and oils, which reduces their robustness and operational time, and existing external environmental barriers complicate integration and increase packaging costs, potentially reducing the performance of devices like microphones by occupying valuable back volume.
Innovation Solution
A MEMS pressure transducer chip with a hybrid integrated environmental barrier structure, featuring a stepped recess structure on the substrate with a first and second recess, where the environmental barrier is placed inside the second recess, providing protection without protruding and maintaining the back volume, and optionally incorporating a monolithically integrated perforated mesh for additional robustness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an external environmental barrier is added to protect the MEMS pressure transducer, then the protection from environmental substances is improved, but the packaging complexity and cost increase
Solution Approach 1:
The environmental barrier is merged with the substrate by integrating it into the recess structure formed on the substrate surface. The barrier and substrate form a unified structure where the barrier is positioned within the recess, eliminating the need for separate packaging components and reducing overall packaging complexity.
Solution Approach 2:
The substrate serves multiple functions: it provides mechanical support for the MEMS pressure transducer and simultaneously houses the integrated environmental barrier within its recess structure. This multi-functionality reduces the need for additional dedicated packaging components.
2Reliability
If an external environmental barrier is added to protect the MEMS pressure transducer, then the protection from environmental substances is improved, but the back volume is reduced
Solution Approach 1:
The environmental barrier is nested within the recess structure of the substrate, similar to a doll within a doll. The barrier is positioned inside the recess rather than as an external addition, allowing it to occupy space that would otherwise be unused or wasted, thereby preserving the back volume.
3Reliability
If a conventional environmental barrier structure is used, then the protection from environmental substances is improved, but additional packaging steps are required
Solution Approach 1:
The recess structure for housing the environmental barrier is formed during the substrate fabrication process itself, before the final assembly. This preliminary action integrates the barrier housing into the substrate manufacturing flow, eliminating the need for separate packaging steps to create the barrier structure.
4Reliability
If the environmental barrier protrudes from the substrate, then the protection from environmental substances is improved, but the back volume is occupied
Solution Approach 1:
The substrate surface is modified locally by forming a recess in the specific region where the environmental barrier needs to be positioned. This local modification allows the barrier to be housed without protruding from the overall substrate boundaries, preserving the back volume while providing protection.
Data Source
AI summary
A method for manufacturing a MEMS pressure transducer chip with a hybrid integrated environmental barrier structure includes a step of providing a substrate comprising at least one membrane, a step of structuring a stepped recess structure into the substrate, the stepped recess structure comprising a first recess having a first lateral width and an adjacent second recess having a larger second lateral width, where the stepped recess structure extends between the membrane and a substrate surface opposite to the membrane, and a step of arranging an environmental barrier structure inside the second recess.