Defect detection system with multilevel output capability and method thereof

A method for performing a calibration mode operation of an open test for analyzing an open in a test route of an integrated circuit comprising:

• connecting a pull-down device between an input terminal of an analog-to-digital converter and ground;
• connecting an open calibration test route between a test input terminal and the input terminal of the analog-to-digital converter;
• applying an input voltage to the test input terminal;
• applying a reference voltage to a reference input terminal of the analog-to-digital converter;
• and
• adjusting the reference voltage until an output code of the analog-to-digital converter being equal to a predetermined code and setting the adjusted reference voltage as a preset reference voltage.

A method for performing a test mode operation of an open test for analyzing an open in a test route of an integrated circuit comprising:

• connecting a pull-down device between the input terminal of an analog-to-digital converter and ground;
• connecting the test route between a test input terminal and the input terminal of the analog-to-digital converter;
• applying an input voltage to the test input terminal;
• applying a preset reference voltage determined by a calibration mode operation of the open test to a reference input terminal of the analog-to-digital converter;
• and
• determining whether the test route is open according to an output code of the analog-to-digital converter.

A method for performing a calibration mode operation of a short test for analyzing a short in a test route of an integrated circuit comprising:

• connecting a pull-down device between an input terminal of an analog-to-digital converter and ground;
• connecting a short calibration test route between a test input terminal and the input terminal of the analog-to-digital converter;
• applying an input voltage to the test input terminal;
• applying a reference voltage to a reference input terminal of the analog-to-digital converter;
• and
• adjusting the reference voltage until an output code of the analog-to-digital converter being equal to a predetermined code and setting the adjusted reference voltage as a preset reference voltage.

A method for performing a test mode operation of a short test for analyzing a short in a test route of an integrated circuit comprising:

• connecting a pull-down device between the input terminal of an analog-to-digital converter and ground;
• connecting the test route between a test input terminal and the input terminal of the analog-to-digital converter;
• applying an input voltage to the test input terminal;
• applying a preset reference voltage determined by a calibration mode operation of the short test to the analog-to-digital converter;
• and
• determining whether the test route is shorted according to an output code of the analog-to-digital converter.