MEMS Actuator Horizontal Motion via Copper Coil
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Solution Overview
Problem
Current methods for forming MEMS actuators and relays lack an efficient approach, particularly in achieving horizontal actuation and low-impedance/high-impedance electrical pathway switching using micro-electromechanical technology.
Innovation Solution
A method involving a conventionally formed single-crystal silicon semiconductor wafer with a dielectric layer and metal interconnect structure, where a seed layer is formed, followed by electroplating copper sections and magnetic material deposition to create an actuation member with a core and floating cantilever section, enabling horizontal movement and electromagnetic actuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional MEMS fabrication processes are used, then vertical actuation can be achieved, but horizontal actuation is difficult to implement
Solution Approach 1:
The patent transitions from conventional vertical actuation to horizontal actuation by changing the dimensional orientation of the cantilever beam and actuation member. The method forms a cantilever beam extending in a first direction with an actuation member that moves horizontally in response to electromagnetic changes, achieving horizontal actuation capability through dimensional reorientation of the MEMS structure.
2Ease of operation
If new MEMS fabrication approaches are developed, then horizontal actuation can be achieved, but compatibility with conventional CMOS processes decreases
Solution Approach 1:
The patent achieves universal compatibility by integrating the horizontal actuation MEMS structure with conventional CMOS backend processes. The method uses standard CMOS-compatible materials and fabrication steps, allowing the same process line to produce both CMOS devices and MEMS actuators with horizontal motion capability, thereby maintaining adaptability while achieving the new functionality.
Solution Approach 2:
The patent modifies fabrication parameters such as deposition temperatures, etch conditions, and material selections to ensure compatibility with conventional CMOS processes. By adjusting these parameters within CMOS process windows, the method achieves horizontal actuation without requiring separate or specialized fabrication lines, maintaining versatility across standard manufacturing platforms.
3Strength
If high processing temperatures are used, then material properties can be optimized, but damage to previously formed structures occurs
Solution Approach 1:
The patent performs preliminary formation of temperature-sensitive structures such as the cantilever beam and electrical contacts before subsequent high-temperature processing steps. By establishing these critical components early in the fabrication sequence, the method protects them from thermal damage while still allowing optimized heat treatment of other materials to achieve desired mechanical and electrical properties.
Solution Approach 2:
The patent carefully controls and adjusts processing temperature parameters throughout fabrication, using lower temperatures for sensitive steps and selectively applying higher temperatures only where material optimization is critical. This parameter optimization allows achieving desired material strength and properties while maintaining the integrity of previously formed structures through controlled thermal exposure.
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 effective horizontal actuation with forces in the range of 100 μN, compatible with conventional backend CMOS processes and requiring relatively low processing temperatures, thus enhancing the efficiency of MEMS actuator and relay formation.
Implementation Method 1
a first copper section and a second copper section are electroplated onto the seed layer
Implementation Method 2
magnetic material deposition to create an actuation member with a core and floating cantilever section, enabling horizontal movement and electromagnetic actuation
Implementation Method 3
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
Data Source
AI summary
A method of forming an actuator and a relay using a micro-electromechanical (MEMS)-based process is disclosed. The method first forms the lower sections of a square copper coil, and then forms an actuation member that includes a core section and a horizontally adjacent floating cantilever section. The core section, which lies directly over the lower coil sections, is electrically isolated from the lower coil sections. The method next forms the side and upper sections of the coil, along with first and second electrodes that are separated by a switch gap. The first electrode lies directly over an end of the core section, while the second electrode lies directly over an end of the floating cantilever section.