Defect detection by thermal frequency imaging

A method for making an electronic integrated circuit, the method comprising:

• fabricating an integrated circuit that includes a power input and a data input;
• applying a periodic power signal to the power input of the integrated circuit, the periodic power signal having a frequency;
• applying a test signal to the data input of the integrated circuit;
• sweeping a surface of the electronic integrated circuit with a laser beam;
• generating a first image using a laser beam reflected from the surface;
• generating a second image using a selected part of the laser beam reflected from the surface, the selected part of the reflected laser beam having a frequency corresponding to the frequency of the power signal;
• and
• detecting defects in the integrated circuit by superposing the first image and the second image.

A system for detecting defects in an electronic integrated circuit that includes a power input and a data input, the system comprising:

• means for powering the electronic integrated circuit with a periodic power signal having a frequency;
• means for supplying an input signal to the data input;
• means for sweeping a surface of the electronic integrated circuit with a laser beam;
• means for generating a first image using a laser beam from the surface and for generating a second image using a selected part of the reflected laser beam, the selected part having a frequency corresponding to the frequency of the power signal;
• and
• means detecting defects in the integrated circuit by superposing the first image and the second image.

A system for detecting defects in an electronic integrated circuit that includes a power input and a data input, the system comprising:

• a periodic signal generator configured to be coupled to the power input;
• an input signal generator configured to be coupled to the data input;
• a laser configured to generate a laser beam;
• a moving mechanism configured to move the laser beam and the electronic integrated circuit relative to each other so as to sweep the laser beam over a surface of the electronic integrated circuit;
• a sensor configured to receive the reflected laser beam and deliver an output signal;
• a frequency analyzer configured to select part of the output signal having a frequency corresponding to the frequency of the power signal;
• and
• a processor configured to generate a first image using the output signal and a second image using the part of the output signal and to superimpose the first image and the second image.