Batch transfer of LIGA microstructures by selective electroplating and bonding

A flip-chip batch transfer process for LIthographie, Galvanoformung and Abformung (LIGA) microstructures has been demonstrated by selective electroplating and bonding. Single layer LIGA microstructures with thickness of 200 /spl mu/m are fabricated on a dummy substrate first. They are then batch transferred to an IC substrate by means of bonding via electroplating. After the selective bonding process, the originally fixed microstructures become free-standing, moveable devices. The electroplating and bonding process is conducted at 50/spl deg/C with applied electroplating current density at 68.3 AM/sup 2/ and it takes about 80 minutes to complete the bonding process. Experimentally, an electrothermally-driven LIGA microgripper has been demonstrated to operate after the batch transfer process. When a maximum input current of 1.6 amp is applied, the tip of the microgripper moves 92 /spl mu/m. This flip-chip assembly process enables a new class of integrated electro-mechanical manufacturing at a low processing temperature massively and in parallel.