Electricity: measuring and testing – Impedance – admittance or other quantities representative of... – Lumped type parameters
Reexamination Certificate
1998-08-27
2001-04-03
Metjahic, Safet (Department: 2858)
Electricity: measuring and testing
Impedance, admittance or other quantities representative of...
Lumped type parameters
C324S762010
Reexamination Certificate
active
06211685
ABSTRACT:
FIELD OF THE INVENTION
The present invention is, in general, directed to a probe for an atomic force microscope or similar instrument. More particularly, the present invention relates to a probe that can be used to measure the spreading resistance or resistivity of an object.
BACKGROUND OF THE INVENTION
Over the last few decades, the electronics industry has undergone a revolution by the use of semiconductor technology to fabricate small, highly integrated electronic devices. The most common semiconductor technology presently used is silicon-based. A large variety of semiconductor devices have been manufactured having various applications in numerous disciplines. Such silicon-based semiconductor devices often include metal-oxide-semiconductor (MOS) transistors, complimentary MOS (CMOS) transistors, bipolar transistors, bipolar CMOS (BiCMOS) transistors, etc.
Each of these semiconductor devices generally includes a semiconductor substrate on which a number of active devices are formed. The particular structure of a given active device can vary between device types. For example, in MOS transistors, an active device generally includes source and drain regions and a gate electrode which modulates current between the source and drain regions. In bipolar transistors, an active device generally includes a base, a collector, and an emitter.
Semiconductor devices, like the ones mentioned above, are used in large numbers to construct most modern electronic devices. As a larger number of such devices are integrated into a single silicon wafer, improved performance and capabilities of electronic devices can be achieved. In order to increase the number of semiconductor devices which may be formed on a given surface area of a substrate, the semiconductor devices must be scaled down (i.e., made smaller). This is accomplished by reducing the lateral and vertical dimensions of the device structure.
Often, it is desirable to study physical properties of the semiconductor device during or after construction of the device. One example is the surface structure of a layer of the semiconductor device. Surface features, deformities, and composition can be studied. Microscopy has been widely used to study surfaces. Optical microscopy has many uses in this regard, however, the resolution of optical microscopes is limited and, furthermore, differences in the device structure may not be readily apparent when viewed optically. Thus, other, more sensitive microscopy techniques, such as electron microscopy, scanning tunneling microscopy, and atomic force microscopy, are often used.
In addition to surface structures, other physical properties, including electrical properties, are also of interest. For example, the surface resistivity at points on a doped surface of a device may provide information about dopant type and concentration. A surface doping profile may be obtained by measuring the resistivity of the surface.
Typically, the surface resistivity is determined using spreading resistance measurements which are obtained by contacting the surface of the device with two contact leads and measuring the resistance to electrical current flowing through the semiconductor device between the two contact leads. Conventional devices used for measuring spreading resistance typically have contact leads with a diameter of 5 &mgr;m or more. This limits the spatial precision and resolution of the surface resistivity measurements and, therefore, the precision of the doping profile.
SUMMARY OF THE INVENTION
Generally, the present invention relates to a probe for use in determining the surface structure of a layer of a semiconductor device and/or measuring the surface resistivity of a layer of a semiconductor device. One embodiment of the invention is a probe for determining a surface characteristic of an object. The probe includes a substrate, a plurality of cantilevers each having a distal end coupled to the substrate, and a plurality of probe tips each coupled to a proximal end of a respective one of the cantilevers for contacting a surface of the object.
Another embodiment of the invention is a probe that includes a substrate divided lengthwise into a first section and a second section. The first section is doped with an n-type material and the second section is doped with a p-type material. A first cantilever is electrically coupled to the first section of the substrate and a first probe tip is electrically coupled to the cantilever and configured and arranged for contact with a surface. A second cantilever is electrically coupled to the second section of the substrate and a second probe tip is electrically coupled to the cantilever and configured and arranged for contact with a surface.
Yet another embodiment of the invention is a device for determining a characteristic of an object. The device includes a probe having a substrate, a plurality of cantilevers each having a distal end coupled to the substrate, and a plurality of probe tips each coupled to a proximal end of a respective one of the cantilevers for contacting a surface of the object. The device also includes a measurement apparatus configured and arranged to determine the characteristic of the object using the probe tips.
A further embodiment of the invention is a method of measuring a characteristic of an object that includes contacting a surface of the object with two probe tips each coupled to a substrate via a cantilever and determining the characteristic of the object using the probe tips.
Another embodiment of the invention is a method of determining a surface resistivity of a layer of a semiconductor device. The method includes contacting a surface of the object with two probe tips each coupled to a substrate via a cantilever. A resistance between two of the probe tips is measured and a surface resistivity is determined from the resistance.
The above summary of the present invention is not intended to describe each illustrated embodiment or every implementation of the present invention. The figures and the detailed description which follow more particularly exemplify these embodiments.
REFERENCES:
patent: 5347226 (1994-09-01), Bachmann et al.
patent: 5475318 (1995-12-01), Marcus et al.
patent: 5507179 (1996-04-01), Gamble et al.
patent: 5929438 (1999-07-01), Suzuki et al.
patent: 6000280 (1999-12-01), Miller et al.
patent: 6045115 (2000-03-01), Takahashi et al.
“Atomic Force Microscopy,” available et at http://www.park.com/spmguide (9 pages). This reference was available prior to filing of the present patent application.
“Analysis of Diffused Profiles,” in Campbell, S.A.,The Science and Engineering of Microelectric Fabrication, cover page and pp. 52-59, Copyright © 1996 by Oxford Universtity Press.
“Measurement Techniques for Diffused (and ion implanted) Layers,” in Wolf, S. et al.,Silicon Processing for the VLSI Era—vol. 1—Process Technology, cover pageand pp. 267-276, Copyright © 1986 by Lattice Press.
“Electrical Properties of Metallic Thin Films” in Wolf, S. et al.,Silicon Processing for the VLSI Era—vol. 1—Process Technology, cover pageand pp. 118-123, Copyright © 1986 by Lattice Press.
Kersten Jeffrey
Stanford Joel R.
Advanced Micro Devices , Inc.
Metjahic Safet
Sundaram T. R.
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