OPEN/SHORT/LOAD Calibration

• Selecting Fixture Type

• Definition of Calibration Kit

• Calibration Compensation Measurement Point Mode

• Calibration of Open Short Load

Other topics about Probe Station Connection Kit (Option 001)

The OPEN/SHORT/LOAD calibration needs to be performed at the tip of Cascade Microtech’s probe head by using the Cascade ISS (Impedance Standard Substrate) to remove residual impedance from the extension cable and probe head.

Set the calibration reference plane to the tip of the probe. Electrical length compensation and fixture compensation (Open compensation and Short compensation) are not executed.

Follow the steps below to select fixture type, define calibration kit, select calibration/compensation measurement point mode, and perform OPEN/SHORT/LOAD calibration of the E4991B.

Selecting Fixture Type

Set the fixture type to none to turn off the electrical length compensation in the E4991B.

1. Press Cal > Accessory > Arbitrary.

Definition of Calibration Kit

The ACP probe head has its own residual parameters such as capacitance (C-Open) at OPEN calibration, inductance (L-Short) at SHORT calibration, and inductance (L-Term) at LOAD calibration. These parameters are defined at each probe pitch and printed inside the probe head’s case cover provided by Cascade Microtech. Set the appropriate values in the Cal Kit Menu of the E4991B, depending on the probe head you are using and its pitch.

1. Press Cal > Calibration > Define Value > enter the definition of the calibration kit.

Calibration/Compensation Measurement Point Mode

The E4991B has two modes (Fixed or User-defined) for defining the measurement points when the calibration and compensation data are measured. Performing calibration in User-defined mode is recommended when using a probe station.

Calibration of Open/Short/Load

The calibration data of Open/Short/Load is measured according to the following procedure while using the Cascade ISS (Impedance Standard Substrate). For more information on how to use ISS, refer to the Cascade Microtech’s manual.

Step 1: Selection of measurement point for calibration/compensation

1. Press Cal > Cal/Compen > User freq.

Step 2: Measurement of open calibration data

1. Set the probe tip to the open position in the ISS.

2. Press Cal > Calibration > Execute Cal > Open.

3. When the measurement of each type of calibration data is finished, a check mark (√) will appear to the left side of the corresponding calibration execution button. This mark indicates that the calibration data is stored.

Step 3: Measurement of short calibration data

1. Set the probe tip to the short position in the ISS.

2. Press Cal > Calibration > Execute Cal > Short.

Step 4: Measurement of load calibration data

1. Set the probe tip to the load position in the ISS.

2. Press Cal > Calibration > Execute Cal > Load.

Step 5: Finishing calibration data measurement and conformation of calibration state

1. When finished, press Cal > Calibration > Execute Cal > Done.

   • The calibration data can be reset by pressing Cal > Calibration > Execute Cal > Cancel. Turning the power OFF also resets the calibration data.

2. Verify that the display of the status bar on the bottom of the screen changes to COR.

3. If you change the probe head or the measurement pitch, you should again perform calibration.