United Microelectronics Corp.

Sung-Nien Kuo

Kuan-Cheng Su

Wen-Hsiung Ko

Jih-San Lee

Kuei-Chi Juan

Yuan-Yu Hsieh

An AC stress test circuit for HCI degradation evaluation in semiconductor devices includes a ring oscillator circuit, first and second pads, and first and second isolating switches. The ring oscillator circuit has a plurality of stages connected in series to form a loop. Each of the stages comprises a first node and a second node. The first and second isolating switches respectively connect the first and second pads to the first and second nodes of a designated stage and both are switched-off during ring oscillator stressing of the designated stage. The present invention also provides a method of evaluating AC stress induced HCI degradation, and a test structure.

Alternating current (AC) stress test circuit, method for evaluating AC stress induced hot carrier injection (HCI) degradation, and test structure for HCI degradation evaluation

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Taipei, Taiwan

Sung-Nien Kuo