MEMS Actuator with Horizontal Magnetic Actuation
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Solution Overview
Problem
Current approaches for forming MEMS actuators and relays lack an effective method that is compatible with conventional semiconductor fabrication processes and requires additional techniques to enhance their performance.
Innovation Solution
The method involves forming a MEMS actuator and relay using a conventionally formed single-crystal silicon semiconductor wafer with a dielectric layer, where a seed layer is deposited, and a magnetic actuation member is created using electroplating, allowing for horizontal movement driven by electromagnetic fields, enabling efficient actuation and switching operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional MEMS actuator approaches are used, then fabrication compatibility is maintained, but actuation force and performance are insufficient
Solution Approach 1:
The actuator is divided into separate functional components: a fixed anchor, a movable beam, and a magnetic actuation member. This segmentation allows each component to be optimized independently while maintaining compatibility with standard CMOS fabrication processes, achieving both high actuation force and ease of manufacture
Solution Approach 2:
The patent employs composite structures combining silicon beams with electroplated magnetic materials (such as cobalt-ferrite or permalloy). This composite approach enables the integration of high-strength mechanical properties with magnetic actuation capabilities, significantly enhancing actuation force while remaining compatible with conventional semiconductor manufacturing
2Reliability
If additional fabrication techniques are added to enhance performance, then actuation performance improves, but process complexity increases
Solution Approach 1:
The patent uses a multi-functional electroplating process that simultaneously deposits magnetic materials, defines geometric patterns, and creates electrical connections. This universal approach enhances actuation performance while avoiding the need for multiple separate fabrication steps, thereby limiting increases in process complexity
Solution Approach 2:
The patent optimizes actuation performance by controlling electroplating parameters such as current density, deposition time, and material composition. By adjusting these parameters within the existing CMOS process framework, high reliability is achieved without adding significant process complexity
3Productivity
If horizontal actuation is implemented, then switching efficiency is improved, but manufacturing difficulty increases
Solution Approach 1:
Instead of moving the contact points horizontally as in traditional designs, the patent inverts the approach by keeping contacts fixed and moving the magnetic actuation member horizontally. This inversion simplifies the manufacturing process while maintaining high switching efficiency through the horizontal movement of the actuation field
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 approach allows for the creation of MEMS actuators and relays with effective actuation forces in the range of 100 μN, compatible with conventional backend CMOS processes, and enables low-impedance and high-impedance electrical pathway switching with low processing temperatures.
Implementation Method 1
the mechanical member in the actuator moves in response to electromagnetic changes in the conditions of an electrical circuit. For example, electromagnetic changes due to the presence or absence of a current in a coil can cause the mechanical member in the actuator to close and open the switch
Implementation Method 2
a magnetic actuation member is created using electroplating, allowing for horizontal movement driven by electromagnetic fields
Implementation Method 3
a seed layer is deposited, and a magnetic actuation member is created using electroplating
Data Source
AI summary
A micro-electromechanical (MEMS) actuator and relay are implemented using a copper coil and a magnetic core. The magnetic core includes a base section that lies within the copper coil, and a cantilever section that lies outside of the copper coil. The presence of a magnetic field in the coil causes the cantilever section to move horizontally away from a rest position, while the absence of the magnetic field allows the cantilever section to return to the rest position.