Method for adjusting resonance frequencies of a vibrating microelectromechanical device

A method for adjusting the resonant frequencies of a vibrating MEMS device comprising the steps of:

• patterning a surface of a structural layer used to form the vibrating MEMS device with a photoresist, the photoresist having open areas where the structural layer used to form the vibrating MEMS device should be etched;
• etching the structural layer used to form the vibrating MEMS device at locations corresponding to the open areas to structurally define the vibrating MEMS device;
• determining a first resonant frequency of the vibrating MEMS device along a first axis and a second resonant frequency of the vibrating MEMS device along a second axis;
• determining a first mass removal amount of the vibrating MEMS device and a first mass removal location of the vibrating MEMS device to alter the first resonant frequency and reduce a resonant frequency difference between the first resonant frequency and the second resonant frequency;
• removing the photoresist at the first mass removal location using laser ablation;
• etching the vibrating MEMS device to remove the first mass removal amount of the vibrating MEMS device at the first mass removal location of the vibrating MEMS device;
• determining a third resonant frequency of the vibrating MEMS device along the first axis and a fourth resonant frequency of the vibrating MEMS device along the second axis;
• determining a second mass removal amount of the vibrating MEMS device and a second mass removal location of the vibrating MEMS device to alter the third resonant frequency and reduce a resonant frequency difference between the third resonant frequency and the fourth resonant frequency;
• coating a portion of the surface of the vibrating MEMS device with a masking material;
• removing the masking material at the second mass removal location using laser ablation;
• and
• etching the vibrating MEMS device to remove the second mass removal amount of the vibrating MEMS device at the second mass removal location of the vibrating MEMS device.