Microcontact

Microcontact refers to an electrical or mechanical contact whose feature size lies in the micrometer range, used to enable switching, sensing, and interconnection within microelectromechanical systems (MEMS) and miniaturized electronic packages. Microcontacts can take the form of standalone contact pads, cantilevered probes, or micro-scale spring contacts integrated with MEMS devices, and they play a central role in achieving reliable electrical connectivity at small scales.

Manufacture and materials: Microcontacts are typically fabricated with MEMS-compatible processes, including photolithography, etching, electroplating, and surface micromachining. Common contact materials include gold for its conductivity and corrosion resistance, nickel or copper alloys for mechanical strength, and carbon-based coatings or diamond-like carbon (DLC) to reduce wear and stiction. Surface cleanliness, oxide layers, and asperities strongly influence contact behavior and resistance, especially under cycling.

Applications: They are used in MEMS switches and micro-relays, micro-probes for electrical testing, high-density interconnects in compact packages, and tactile or force sensors. In addition, microcontacts support micropositioning mechanisms and alignment features in precision instruments, where small contact areas must endure repeated engagement.

Performance and reliability: Key metrics include contact resistance, contact bounce, wear, adhesion, and lifetime under repetitive actuation. Challenges include stiction at small gaps, corrosion, and arcing at higher voltages. Reliability is enhanced through protective coatings, optimized contact geometry, surface texturing, and clean fabrication to minimize asperity-induced failures.

Research and trends: Ongoing work aims to lower contact resistance, extend lifetimes, and enable robust low-power switching. Advances include novel coatings, lubrication strategies at micro scales, and integration with flexible or soft electronics. Standards and testing methods derive from MEMS reliability protocols and microelectronic packaging guidelines.