Patent ID: 6906341

Claim:
A test apparatus comprising: a substrate retainer for holding a substrate having a plurality of chips; a probe card having an array of probes aligned in rows and columns, wherein each of the probes is for contacting respective chips of the substrate held by the retainer and each includes a plurality of probe needles; a tester which conducts a test routine by generating test signals and by receiving and analyzing return signals; a test head for sending the test signals from the tester to the probe card, and for sending the return signals from the probe card to the tester; and a main controller comprising a test result database for storing test data analyzed by the tester for executing a cleaning error detection program to determine whether the test data contains cleaning errors resulting from a lack of cleanliness of the probe needles of the probes, and a cleaning error database for storing sample test data containing cleaning errors, and wherein the cleaning error detection program compares the test data stored in the test result database and the sample test data stored in the cleaning error database.