Abstract: A wafer testing machine and a method for training an artificial intelligence (AI) model to test wafers are provided. The wafer contains multiple dies. The method includes the following steps of: determining a target die from the dies; selecting multiple reference dies close to the target die based on the target die and a preset range; generating a main training data which includes a measured value of the target die and the measured value of each reference die; generating an auxiliary training data which indicates whether each reference die is a passed die or a failed die; and training the AI model using the main training data and the auxiliary training data.

Abstract: A circuit having multiple scan modes is disclosed. The circuit includes a first circuit block and a second circuit block. The first circuit block corresponds to a first scan mode of the multiple scan modes, and the first circuit block includes at least one first scan chain for receiving a test signal from an external automatic test equipment. The second circuit block corresponds to a second scan mode of the multiple scan modes, and the second circuit block includes at least one second scan chain for receiving another test signal from the external automatic test equipment. The second scan chain includes at least one specific flip-flop positioned in the first circuit block, and the specific flip-flop is configured to drive the second circuit block.

Abstract: A test pattern generating method for generating a test pattern for a circuit under test. The test pattern generating method comprises: (a) computing a plurality of signal delay values which a plurality of cells have due to different defects; (b) comparing the signal delay values and signal path delay information of a target circuit to generate a fault model; and (c) generate at least one test pattern according to the fault model.

Abstract: A circuit applied to multiple scan modes is disclosed, wherein the circuit can increase fault coverage during chip testing without using scan chain wrappers. The circuit includes a first circuit block and a second circuit block. The first circuit block corresponds to a first scan mode of the multiple scan modes, and the first circuit block includes at least one first scan chain for receiving a test signal from an external automatic test equipment. The second circuit block corresponds to a second scan mode of the multiple scan modes, and the second circuit block includes at least one second scan chain for receiving another test signal from the external automatic test equipment. The second scan chain includes at least one specific flip-flop positioned in the first circuit block, and the specific flip-flop is configured to drive the second circuit block.