Simultaneous and Separate Driving of Multiple AFM Tips

Physical Sciences : Mechanical

Available for licensing

Inventors

  • Michael Cullinan, Ph.D. , Mechanical Engineering, Cockrell
  • Tsung-Fu Yao , Nascent

Background/unmet need

Atomic force microscopy is a widely used tool in nano-technology due to its extremely high imaging resolution. In industrial fabrication, manufacturers seek an in-line inspection system to monitor the quality of products with nano-scaled features. However, most nano-resolution microscopic instruments, such as AFM and SPM, can only be used to record measurements over an area typically not larger than a few square micrometers. The limited scan area makes it difficult to rapidly determine the overall quality of entire specimens which are usually on the order of one square millimeter in area.

While is is not impossible to scan the entire area of a specimen with an AFM or SPM, the process would be prohibitive in the amount of time it would require. Even though some AFM/SPM manufacturers utilize an array of AFM tips to make measurements over larger areas, existing technology does not allow independent actuation of the tips in the X, Y, and Z directions. As a result, there is an exceedingly tight tolerance for parallelism between the array of tips and the sample.

Invention Description

This invention allows for independent actuation of multiple AFM tips relative to a sample. Each AFM tip can be positions in the X and Y directions to be above a desired feature and can be actuated in the Z direction to be at the optimal height for surface measurement. The invention allows for simultaneous measurements over a specimen with an irregular or curved surface. The device is simple and compact, making it easy to integrate into existing manufacturing lines. The position of each of the probes can be optimized such that the location of each probe corresponds with an area of interest over a relatively large sample, which may aid in determining the overall quality of samples such as silicon wafers.

Benefits/Advantages

  • Independent actuation of probes for optimum sample to probe distance
  • Can be utilized to scan curved, angled, or irregular surfaces
  • High throughput for specimen compared with conventional processes
  • Significantly reduced setup time compared with conventional processes
  • Reduction in inspection time scales linearly with number of probes on device
  • Potential to enable in-line inspection in nano-technology manufacturing

Features

  • Compact and low in mass
  • Multiple AFM or SPM probes can be positioned simultaneously
  • Multiple probes can be positioned independently in the X, Y, and Z directions
  • Customizable positioning of probes
  • Stackable so that multiple devices can be used to increase the number of probes on sample

Market potential/applications

This invention has potential applications in semiconductor fabrications, nano/microscope manufacturers, biomedical industries, and laboratory settings.

Development Stage

Proof of concept

IP Status

  • 1 U.S. patent application filed