The following reference guide (developed by Prometrix for the OmniMap system) suggests the best four point probe tip specifications for a variety of silicon wafer types. We offer the service of testing wafers/materials to determine the optimum tips specifications. Please contact Bridge Technology for further information.
TC=tungsten carbide tip material. Osmium alloy tips are also available, but are rarely justified.
Please note that this chart was developed decades ago when silicon wafers were less advanced in design and materials. For example, the reference to using a type “A” probe for “metals” refers to probing aluminum which was the primary metal used on silicon wafers. The 1.6 mil (40 micron) sharp tips recommendation was to punch through native aluminum oxide. However, this did not take into consideration the use of other metals such as copper, nor that fact that some very thin aluminum layers (e.g., 50nm) are probably more suited for measurement with a type B or C probe which has a larger tip radius. Metals such as copper can also be successfully measured with a larger tip radius which leaves less marking on the surface and should provide for longer tip life. Additionally, as of this writing (2012) many of the metal layers which Jandel Engineering receives for testing are measured in 10’s of Angstroms instead of microns, which makes a significant difference in the probe tip specifications recommendation.
| For measuring metals | |||||
| General purpose head for implantation, doped poly, epitaxy, diffusion. | |||||
| For high impedance surfaces such as low implant doses and shallow junctions. | |||||
| For very difficult implant and high impedance surfaces beyond the 8.0 mil | |||||
| For substrate measurements |
Four-Point-Probes is a division of Bridge Technology. To request further information please call Bridge Technology at (480) 219-9007 or send e-mail to Joshua Bridge at: sales@bridgetec.com
