Semiconductor strain gage and method of fabrication

US11906375B1 · kind B1 · utility

Assignee

• Piezo-Metrics Inc · US

Inventors

• Franklin Wong · Simi Valley, US
• Robert Mueller · Kenmore, US
• Kimberly Lakea Harrison · Martinez, US
• Farzad Khademolhosseini · Burlingame, US
• Carolyn Bianco · San Francisco, US

Key dates

• Filing date: Mar 21, 2022
• Grant date: Feb 20, 2024
• Expiry date: Apr 8, 2042

Classification

• Technology area (CPC G): Physics
• CPC primary: G01L1/205
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

The present disclosure is directed to methods for low-cost, high-volume production of strain gages having substantially uniform gage-to-gage resistances. Strain gages in accordance with the present disclosure are sculpted from a device layer of a semiconductor-on-insulator wafer using deep reactive ion etching, thereby enabling well-controlled electrical properties and physical dimensions of the strain gages. In some embodiments, groups of fully fabricated strain gages are physically connected to handling frames via sprues to facilitate handling, automated assembly, and/or tracing of individual gages from the beginning of fabrication through final packaging. In some embodiments, sprues are configured to mitigate accidental separation of the gages from their frames while simultaneously enabling their removal in response to specific forces applied by a handling tool.