Arm array for devices

A device, comprising:

• an anchor structure;
• and
• a plurality of arm arrays connected to the anchor structure, each arm array comprising:
• a first array of spaced-apart fingers extending from a first arm in a longitudinal direction;
• a second array of spaced-apart fingers extending from a second arm in the longitudinal direction, wherein the array of first fingers and the array of second fingers are separated from each other by a lateral trench;
• and
• one or more longitudinal micro-springs connecting each finger in the array of first fingers to adjacent fingers in the array of second fingers.

A method for making an arm array, comprising:

• receiving a package that comprises a top wafer bonded to a bottom wafer;
• patterning the top wafer to form a first set of trenches, a second set of trenches, and at least one pillar;
• forming a dielectric layer on exposed surfaces of the first set of trenches, the second set of trenches, and the at least one pillar;
• forming a metal layer upon the at least one pillar to obtain at least one micro-spring precursor structure;
• optionally forming at least one sacrificial spacer upon the at least one micro-spring precursor structure and forming a dielectric layer on exposed surfaces of the at least one micro-spring precursor structure and the at least one sacrificial spacer;
• depositing an electrically conductive material into the first set of trenches to form an array of first fingers;
• depositing an electrically conductive material into the second set of trenches to form an array of second fingers;
• forming openings in at least two fingers in the array of first fingers;
• forming a metal cap that fills the openings of the at least two fingers in the array of first fingers to form rivets;
• etching to remove the optional at least one sacrificial spacer and form a cavity within the top wafer;
• and
• annealing to convert each micro-spring precursor structure into a micro-spring.