MEMS Sensor Packaging with Wafer-Level Pressure Port
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Solution Overview
Problem
Conventional MEMS device packaging solutions for pressure sensors are costly and lack standardization, often requiring specialized processes and materials that are not compatible with all applications, particularly due to issues with media compatibility and the need for exposed sensor surfaces.
Innovation Solution
A MEMS device package design that predefines a pressure port at the wafer level, using a framing element to expose the sensor to the environment while protecting bond pads and wires with mold compound, allowing for standardized and cost-effective packaging processes compatible with a wide range of sensor applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a premolded cavity package with gel filling is used to protect bond pads and wires, then protection from external media is provided, but media compatibility is inadequate and material cost is high
Solution Approach 1:
The invention extracts the protective function from the gel material and transfers it to the mold compound by creating a sealed cavity structure. The mold compound itself forms the protective barrier against external media, eliminating the need for additional gel filling while maintaining protection of bond pads and wires.
Solution Approach 2:
The invention changes the material parameter by using mold compound (a solid, structurally stable material) instead of gel (a soft, media-permeable material). This parameter change provides superior media compatibility while maintaining protective functions.
2Adaptability or versatility
If a premolded cavity package is used, then sensor die can be exposed to ambient environment, but package cost is high and standardization is reduced
Solution Approach 1:
The invention makes the mold compound serve multiple functions: it provides mechanical protection, seals the cavity, protects bond pads and wires, and enables standardized manufacturing. This multi-functionality eliminates the need for specialized gel filling processes and reduces overall package cost.
Solution Approach 2:
The invention merges the protective cavity structure with the mold compound material itself. Instead of using separate components (cavity structure + gel filling), the mold compound forms both the cavity walls and the protective sealing medium, simplifying the manufacturing process.
3Adaptability or versatility
If a backside pressure port is created on sensor die, then pressure sensing is enabled, but specialized MEMS processes are required increasing cost
Solution Approach 1:
The invention performs preliminary action by pre-defining the pressure port location and structure during the mold compound packaging process, before final assembly. This allows the pressure port to be created as part of the standardized packaging process rather than requiring specialized MEMS wafer fabrication steps.
Solution Approach 2:
The mold compound acts as an intermediary that enables pressure port creation without modifying the sensor die itself. The pressure port is formed in the mold compound packaging material, which mediates between the sensor die and the external environment, eliminating the need for direct die modification.
Data Source
AI summary
Embodiments relate to sensor and sensing devices, systems and methods. In an embodiment, a micro-electromechanical system (MEMS) device comprises at least one sensor element; a framing element disposed around the at least one sensor element; at least one port defined by the framing element, the at least one port configured to expose at least a portion of the at least one sensor element to an ambient environment; and a thin layer disposed in the at least one port.