Rigorous calibration and verification procedures are essential to ensure the test system’s long-term stability and its ongoing compliance with the waveform specifications defined in Table 1. These protocols guarantee the validity of test data by confirming that the equipment performs as expected before and during device stressing.

Calibration and Verification Schedule

The test system shall be qualified and verified according to the following mandatory schedule:

• Initial Equipment Qualification: A comprehensive qualification, meeting all specifications in Table 1, must be performed upon initial acceptance of a new or repaired test system.
• Periodic Recalibration: Full recalibration is required at a minimum interval of every 12 months. Recalibration is also mandatory whenever equipment repairs are performed that may affect the discharge waveform.
• Routine Waveform Verification: The short-circuit waveform must be verified at the beginning of each work shift or any time a socket or DUT board is changed. If the waveform is found to be out of compliance with Table 1, all device testing must be halted until the system is corrected and re-verified.

Qualification Procedure

The formal equipment qualification process involves the following steps:

1. Waveform Measurement: The current waveform must be measured using the shorting wire at all specified test voltage levels (100V, 200V, 400V). Additionally, the waveform must be measured with the 500 ohm resistor at the 400V level to verify Ipr and I100 parameters.
2. Repeatability Check: The system’s repeatability must be confirmed by delivering a minimum of 5 consecutive positive pulses and 5 consecutive negative pulses at a voltage level specified in Table 1. All captured waveforms must meet the specification to pass the repeatability check.

“Worst-Case Pin” Verification

For routine verification, it is mandatory to use a pin combination on the DUT socket that provides the most stringent test of the system’s performance. This is known as the “worst-case pin” combination and its identification must be documented.

1. The objective is to identify the pin pair on the DUT socket (one connected to Terminal A, one to Terminal B) that produces a waveform closest to the specification limits defined in Table 1.
2. Identify the DUT socket pin with the shortest wiring path from the pulse generator. This pin shall be connected to Terminal B.
3. Identify the DUT socket pin with the longest wiring path from the pulse generator. This pin shall be connected to Terminal A.
4. Measure the current waveform by connecting a shorting wire between this designated pin pair.
5. This pin combination shall be documented and designated as the “worst-case” pair for all subsequent routine verifications.

Safety

• All personnel must receive comprehensive operational and safety training before using the ESD test equipment.
• A qualified safety engineer or representative should inspect the operating location, particularly to ensure that the equipment is not operated in a combustible or hazardous environment.

With the equipment fully calibrated and verified, the focus shifts to the standardized execution of the ESD test on the device itself.