Probe Station FAQ
1. How do I align my Laser Head on an Alessi F/A probe station?
Aligning the laser on the Alessi system is an easy procedure. The laser is already aligned internally, so the output beam is aligned to exit the center of the aperture and run along the axial path of the optical system. No internal adjustment inside the laser is necessary.
The steps required for external alignment are detailed in the Technical Brief: Alignment of Laser Head on Alessi Failure Analysis Stations
2. What performance improvement does a guarded chuck provide?
Even when taking measurements using probes placed on the top of the wafer, chuck guarding plays an important role in determining measurement performance. A low-leakage and low-noise triaxial chuck is essential for measuring device currents as low as 1 fA.
For complete information on the beneficial effects of chuck guarding see the Cascade Microtech Technical Briefs: The Importance of Chuck Guarding in Top of Wafer Measurements and Reducing Measurement Noise In Thermal Wafer Probing Systems.
3. What is the capacitance variation across an 8" wafer using a Summit AttoguardTM shielded station?
The capacitance variation is specified at 3 femtoFarad. For more information on the CV and IV advantages of the Cascade AttoguardTM system see the Cascade Microtech Technical Brief: Improved CV and IV Thermal Measurement Capabilities Using the Patented AttoGuard.
4. Does a shielded probe station allow me to reach the ultimate low current performance of my test equipment?
The Cascade Summit Series probe stations with patented MicroChamberTM technology and AttoguardTM shielding allows for current measurements down to 1 fA, which is the measurement resolution of the Agilent 4156B parameter analyzer.
For more information on probe station features that enable these low-level current measurements please see Cascade Microtech Application Notes: Recent Advances in DC Parametric Measurements.
5. How do I configure my Summit system to make a 4-port capacitance measurements using the Agilent 4284 LCR meter?
Cascade has strived to provide an on wafer probing solution for low-level 4-port capacitance measurements. This solution includes BNC to triax adapters, cables of a specific length to accommodate accurate cable compensation, and triaxial probes capable of connecting the Hi-Pot and Lo-Pot guard voltages together close to the device under test.
A complete schematic drawing, and a list of component parts needed to make this measurement, are available in the Cascade Microtech Configuration Guide: DC/CV Parametric Probing Configuration Guide, and measurement tips are in the Application Note: Achieving High-Accuracy On-Wafer Capacitance Measurements.
