Probe for a scanning probe microscope and method of manufacture

Abstract

A probe assembly for an instrument and a method of manufacture includes a substrate and a cantilever having a length independent of typical alignment error during fabrication. In one embodiment, the probe assembly includes a buffer section interposed between the substrate and the cantilever. The cantilever extends from the buffer section and a portion of the buffer section extends beyond an edge of the substrate. The portion of the buffer section is more stiff than the cantilever. The corresponding method of producing the probe assembly facilitates batch fabrication without compromising probe performance.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention is directed to a probe assembly for a metrology instrument used to measure a property of a sample, and more particularly, a probe assembly including a cantilever having a short length to support high bandwidth operation, and configured for ready batch fabrication. [0003] 2. Description of Related Art [0004] Scanning probe microscopes (SPMs), such as the atomic force microscope (AFM), are devices which use a sharp tip and low forces to characterize the surface of a sample down to atomic dimensions. Generally, the tip of the SPM probe is introduced to the sample surface to detect changes in the characteristics of the sample. By providing relative scanning movement between the tip and the sample, surface characteristic data can be acquired over a particular region of the sample and a corresponding map of the sample can be generated. [0005] In an AFM, for example, in a mode of operation called cont...

AI Technical Summary

Benefits of technology

[0012] The preferred embodiment overcomes the drawbacks of prior art systems by providing a probe that is manufactured so that its length is independent of inherent alignment error(s) associated with the process. In one embodiment, the probe includes a buffer section intermediate the substrate and the cantilever, thus eliminating the drawbacks associated with the uncontrollable offset (caused by alignment error during dicing) present in known techniques of batch fabricating probes. The buffer section allows the length of the cantilever to be precisely defined, in the sub-20 micron range, and is sufficiently stiff to allow the cantilever extending therefrom to freely oscillate at high resonant frequencies. In an alternative in which the probe is etched from the front and back sides of a substrate, the length of the cantilever is independent of conventional alignment errors caused by orthogonality and parallax issues during the etch fabrication process.

Problems solved by technology

One significant drawback associated with using probes having short cantilevers, however, is that for a number of reasons it is very difficult to bulk manufacture probes having cantilevers with such short lengths, i.e., in the sub-50 micron range.

In the latter regard, when producing short levered probes, it is nearly impossible to accurately control the dicing from the backside of the batch fabricated probe assemblies given alignment inaccuracies in the process.

This offset cannot be readily controlled.

As a result, when batch fabricating such a probe, the uncontrollable offset, “O”, as shown in FIG. 2C, present when the probes are diced operates to limit the manufacturer's ability to produce repeatable probe assemblies having a short, for instance, sub-20 micron, length.

More particularly, standard mechanical dicing operations have inherent alignment errors (typically, as much as tens of microns) that, though acceptable for fabricating conventional probes, is unacceptable for fabricating the type of short probes contemplated herein.

Due to processing limitations, performing this etch with sufficiently high precision to cost-effectively define cantilevers 36 having repeatable lengths in the sub-20 micron scale is generally impossible, as understood in the art.

It is very difficult to control these etches to define short (e.g., sub-20 micron) levers because of orthogonality and parallax considerations, as understood in the art.

Images