INPUT / OUTPUT CONTACT FORMATION PROCESS

摘要

PURPOSE: To produce input/output bump bondings in fine pitches by employing a negative resist and lift-off process. CONSTITUTION: At least one integrated circuit is formed on the uppermost surface of a GaAs wafer 1. A mesa 3 is pattern-formed on the wafer 1 and electric contacts 15 are formed in a plurality of regions 5 on the mesa 3. To form the mesa and the electric contacts, a negative type dry resist layer 7 with at least 15μm thickness is formed on the integrated circuit of the wafer 1. The resist is cured by pattern forming method including development after exposure by irradiation of light with 350nm or shorter wavelength to the selected part and at the same time windows 11 having recessed corners are formed. A metal layer of such as indium is deposited on the resultant wafer and then the layer 7 is lifted off to form input/output contacts 15 in the integrated circuit.