×

Dual-laser voltage probing of IC's

  • US 5,905,577 A
  • Filed: 03/15/1997
  • Issued: 05/18/1999
  • Est. Priority Date: 03/15/1997
  • Status: Expired due to Term
First Claim
Patent Images

1. A method of probing an integrated circuit device with laser light to acquire samples of a waveform appearing on the device as the device is exercised by a repetitive pattern of test vectors, comprising:

  • a. applying a probe-laser pulse 832 to a region of the device at a selected time during each repetition of the pattern of test vectors and detecting energy reflected from the region as the probe-laser pulse is applied, to thereby produce a reflected-light probe sample;

    b. applying a reference-laser pulse 842 to said region of the device at a time during each repetition of the pattern of test vectors which is displaced relative to the time at which the probe-laser pulse is applied, and detecting energy reflected from the region as the reference-laser pulse is applied, to thereby produce a reflected-light reference sample;

    c. preparing a ratio of the reflected-light probe sample and the reflected-light reference sample for each repetition of the pattern of test vectors to produce a waveform sample having improved signal-to-noise relative to the reflected-light probe sample.

View all claims
  • 4 Assignments
Timeline View
Assignment View
    ×
    ×