Elastic Anchoring in Micromechanical Sensor Devices
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Solution Overview
Problem
Micromechanical sensor devices, particularly those using silicon chips in chip scale packages, face challenges with stress sensitivity due to direct flip chip installation on circuit boards, leading to deformation and potential damage of electrical contacts during bonding and usage.
Innovation Solution
The implementation of an elastically coupled electrical connecting element using a spring element between anchoring areas in the micromechanical functional layers reduces stress sensitivity by allowing smaller contact areas and preventing mechanical overstraining, while also enabling flexible placement and stress-free transmission of contact areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If direct flip chip installation of silicon chips on application circuit boards is used, then chip scale packaging and miniaturization are achieved, but stress effects are strongly coupled into the MEMS chip causing deformation and potential damage
Solution Approach 1:
The patent introduces an elastic anchoring area as an intermediary element between the rigid MEMS chip structure and the application circuit board. This elastic anchoring area acts as a stress-absorbing mediator that decouples the direct stress transmission path, allowing the chip to be installed in chip scale package format while protecting the sensitive MEMS structures from deformation and damage.
Solution Approach 2:
The patent changes the mechanical parameter of the anchoring area by making it elastic rather than rigid. This parameter change allows the anchoring area to deform under stress, thereby absorbing stress effects and preventing them from being strongly coupled into the MEMS chip, thus reducing stress sensitivity while maintaining miniaturization benefits.
2Area of stationary object
If smaller contact areas are used in chip scale packages, then footprint is reduced, but mechanical overstraining and damage during bonding and usage increase
Solution Approach 1:
The patent implements beforehand cushioning by designing the anchoring area with elastic properties prior to bonding and usage. This elastic structure serves as a pre-established protective mechanism that cushions the smaller contact areas from mechanical overstraining during bonding processes and subsequent usage, thereby maintaining contact connection reliability despite the reduced contact area size.
Solution Approach 2:
The patent changes the mechanical parameter of the anchoring area from rigid to elastic, which fundamentally alters how stress is distributed. This parameter change enables smaller contact areas to withstand bonding and usage stresses without overstraining, as the elastic material can deform to absorb peak stresses and then recover, thus maintaining reliability with reduced footprint.
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
This solution enhances the robustness and reliability of the mechanical or electrical contact connection between MEMS and ASIC substrates, reducing stress-induced damage and extending the service life of the sensor device.
Implementation Method 1
an elastically coupled electrical connecting element using a spring element between anchoring areas in the micromechanical functional layers reduces stress sensitivity by allowing smaller contact areas and preventing mechanical overstraining
Data Source
AI summary
A micromechanical sensor device includes: an ASIC substrate having a first front side and a first rear side; a rewiring element formed on the first front side and including multiple stacked conductor levels and insulating layers; a MEMS substrate having a second front side and a second rear side; a first micromechanical functional layer formed on top of the second front side; and a second micromechanical functional layer formed on top of the first micromechanical functional layer and connected to the rewiring element. In the second micromechanical functional layer, a movable sensor structure is anchored on one side via a first anchoring area, and an electrical connecting element formed in a second anchoring area is anchored on one side on the ASIC, and the first and second anchoring areas are elastically connected to one another via a spring element.