MEMS Stator Interconnect Packaging for Compact Sensor Wire Bonding
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Solution Overview
Problem
Existing MEMS devices face challenges in miniaturization and reliability due to long wire-bonds that are susceptible to movement and shorting in harsh environments, especially when the image sensor is located below the circuit board, which also consumes significant circuit-board area.
Innovation Solution
The MEMS device is packaged with the stator providing an electrical connection point, using wire bond interconnects to connect the sensor to the stator pad and an underlying electrical distribution substrate through a via, allowing for compact packaging and free movement of the sensor and actuator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the image sensor is located below the circuit board with long wire-bonds, then electrical connection is achieved, but the device area increases and reliability decreases due to susceptibility to movement and shorting
Solution Approach 1:
The patent transitions from a planar connection architecture to a three-dimensional vertical connection architecture. The sensor is positioned above the stator with electrical connections routed vertically through the stator structure via vias, rather than requiring long horizontal wire-bonds across the circuit board. This dimensional change reduces the footprint on the circuit board while maintaining electrical connectivity.
Solution Approach 2:
The stator structure serves dual functions: it provides the mechanical support structure for the sensor and simultaneously serves as the electrical connection pathway. The stator's outer frame and floor structure are integrated with electrical traces and vias, allowing the same component to fulfill both structural and electrical connectivity roles, eliminating the need for separate long wire-bond interconnects.
2Reliability
If long wire-bonds are used to connect the sensor, then electrical connection is achieved, but the risk of bond-to-bond shorting increases in harsh environments
Solution Approach 1:
The patent extracts the electrical connection function from the traditional wire-bond interconnect and integrates it directly into the stator structure. Electrical traces are formed on and within the stator itself, eliminating the need for separate wire-bonds that extend from the sensor through space to the circuit board. This removes the vulnerable wire-bond segment that could cause shorting in harsh environments.
3Volume of moving object
If compact packaging is achieved with the sensor above the stator, then device miniaturization is improved, but electrical connection complexity increases
Solution Approach 1:
The patent merges the mechanical stator structure with the electrical interconnect structure. The stator's outer frame, floor, and internal features are integrated with conductive traces and via structures, combining what would traditionally be separate components (mechanical support and electrical interconnect) into a single unified structure. This reduces overall device volume while the integration is achieved through standard semiconductor manufacturing processes.
Data Source
AI summary
A MEMS device is provided with an actuator stator providing an electrical connection point. The MEMS device includes an electrical distribution substrate, and an actuator stator positioned above it. The actuator stator has a floor and an outer frame extending up from the floor. The MEMS device includes a stator pad disposed on the outer frame and above the electrical distribution substrate. The MEMS device also includes an actuator rotor suspended above the floor, within the outer frame, with a sensor mounted thereon. A wire bond interconnect electrically couples the sensor to the stator pad. In some embodiments, the outer frame includes a via extending therethrough which electrically connects the stator pad with the electrical distribution substrate, enabling an electrical connection between the sensor and the electrical distribution substrate. In some embodiments, a second wire bond interconnect electrically connects the stator pad and the substrate.