Wafer Probing Systems
for Electron Microscopes
The actual small wafer structures cannot be observed in a light microscope anymore. Every institution that investigates in semiconductor structure development has to overcome this problem, sooner or later. Therefore only two instruments can be used: the AFM expanded to a Wafer Prober or the SEM equipped with Wafer Prober. The AFM cannot resolve structures that are only 2-dimensional. This is a limitation for a lot of structures. And an AFM has a typical maximum scanning range of about 20x20 um2. It can take hours to find a certain sample position with this slow device. The Electron Microscope can zoom from cm2 sized areas into a few 10 nm2 sized areas within a few seconds. And any kind of structures are visible in a SEM, independent if they are flat or not. Therefore Wafer Probing in a SEM is the best solution. A high-end SEM is not required, any (elder) SEM can be used for this application.
Measurement examples made by the Taiwanese semiconductor company TSMC are described in a paper (download area on the right) and here.
Klocke Nanotechnik offers a complete series of Wafer
Probing products, from single manipulators over sets of manipulators,
different levels of automation and software - up to complete automatic
systems including pattern recognition software. The manipulators resolution
of 2 nm is by far enough to hit any existing wafer structure, also in
the next years.
Depending on the Electron Microscope that shall be used individual Nanorobotics
manipulators are configured, including development of the complete
Details about different probe tips and tools for a secure tip approach
towards all kind of samples are described at Accessory.
After the tip reached the sample:
Depending on the amount of manipulators used different current/voltage diagrams can be measured, e.g. between the three pads of a FET. Software modules show and store these diagrams:
Using our process control sequencer the following sequence can be executed completely automatically: Movement of the probe tips to certain sample areas (e.g. with the help of our vision system and pattern recognition), tip approach, measurement and storage of an I/V diagram, tip removal, ... if necessary on an array of sample positions.