Wire-Bond Dampers for MEMS Shock Absorption Without Stiffness Tradeoff
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Solution Overview
Problem
MEMS devices are susceptible to damage from sudden shocks, which can lead to failure or reduced performance, and increasing spring stiffness to mitigate this issue compromises sensitivity.
Innovation Solution
Incorporation of wire-bond dampers, such as out-of-plane and in-plane dampers, formed by wire bonding, to absorb kinetic energy and prevent collision with surrounding structures, maintaining sensitivity by providing damping independent of the spring system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spring stiffness is increased to mitigate shock damage, then reliability is improved, but sensitivity deteriorates
Solution Approach 1:
The shock protection function is segmented from the spring system by introducing a separate wire-bond damper. The damper is independently configured to absorb shock energy through its own deformation, while the spring maintains its original stiffness and sensitivity characteristics. This functional segmentation allows each component to optimize for its specific purpose without compromise.
Solution Approach 2:
The wire-bond damper acts as an intermediary element between the movable mass and the housing structure. During shock events, the damper absorbs kinetic energy through deformation, serving as a buffer that protects the movable mass from direct impact with the housing while allowing the spring to maintain its normal operation for sensitivity.
2Reliability
If wire-bond damper is added to absorb shock energy, then reliability is improved, but device complexity increases
Solution Approach 1:
The wire-bond damper serves multiple functions: it absorbs shock energy, protects the movable mass from damage, and can be integrated into existing wire-bonding structures without requiring entirely separate mechanical components. This multi-functionality reduces the need for additional dedicated shock protection mechanisms.
Solution Approach 2:
The damper's effectiveness is tuned by adjusting parameters such as wire diameter, bond length, and material properties. By optimizing these parameters, the damper provides adequate shock absorption with minimal structural complexity, achieving protection without excessive design complexity.
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 wire-bond dampers effectively absorb shock energy, preventing damage to the movable mass while maintaining the sensitivity of the MEMS structure by not impacting the spring's performance.
Implementation Method 1
the wire-bond damper absorbs shock energy... configured to dampen in-plane and out-of-plane shock to the movable mass
Data Source
AI summary
Various embodiments of the present disclosure are directed towards a microelectromechanical systems (MEMS) package comprising a wire-bond damper. A housing structure overlies a support substrate, and a MEMS structure is between the support substrate and the housing structure. The MEMS structure comprises an anchor, a spring, and a movable mass. The spring extends from the anchor to the movable mass to suspend and allow movement of the movable mass in a cavity between the support substrate and the housing structure. The wire-bond damper is on the movable mass or structure surrounding the movable mass. For example, the wire-bond damper may be on a top surface of the movable mass. As another example, the wire-bond damper may be on the support substrate, laterally between the anchor and the movable mass. Further, the wire-bond damper comprises a wire formed by wire bonding and configured to dampen shock to the movable mass.