Failure Analysis for GaAs MMIC Amplifier with Metallized Via Hole

Metallized via is an important grounding technology in the gallium arsenide Monolithic Microwave Integrated circuit(GaAs MMIC) design, but its defects will lead to serious failure of the circuit. In this paper, we report a failure case of GaAs MMIC amplifier which is caused by the defects in the metallized via. The main abnormal phenomena of the amplifier are the unexpected decreases in current and gain. Through a detailed analysis, we find that the circuit is opened between the metallized PAD and the heat-sink material. The cutting the area shows that there are cracks in the metal wall of the via hole, and poor contact with semiconductor materials. Through analyzing the manufacturing process, control deviation of via hole etching and cleaning, sputtering and gold-plating process will lead to the defects, at the same time, the internal stress will increase the exposure of the defects. This failure case is not only a guidance for abnormal phenomena check, but also a reference for manufacturing process development.