US4747698A — Scanning thermal profiler

Claim 1

Independent Claim 159 words

Apparatus for investigating surface structures present on the surface of a sample to be investigated irrespective of the materials involved comprising: probe means including a fine scanning tip; means for relatively positioning said scanning tip and the surface to be investigated; a heat source for heating said scanning tip to a controlled temperature when said scanning tip is remote from the sample surface; temperature sensing means at said scanning tip for detecting variations in the tip temperature when said scanning tip is moved to a separation distance in close proximity with the sample surface; means for scanning said scanning tip across the sample surface in close proximity therewith; means for automatically controlling the separation distance between said scanning tip and the sample surface in response to the temperature variations such that the temperature variations remain substantially constant during scanning; and means for graphically displaying the spatial coordinates of said scanning tip to produce a topographical map of the surface.

Claim 2

Dependent Claim 159 words

Apparatus for investigating surface structures present on the surface of a sample to be investigated irrespective of the materials involved comprising: probe means including a fine scanning tip; means for relatively positioning said scanning tip and the surface to be investigated; a heat source for heating said scanning tip to a controlled temperature when said scanning tip is remote from the sample surface; temperature sensing means at said scanning tip for detecting variations in the tip temperature when said scanning tip is moved to a separation distance in close proximity with the sample surface; means for scanning said scanning tip across the sample surface in close proximity therewith; means for automatically controlling the separation distance between said scanning tip and the sample surface in response to the temperature variations such that the temperature variations remain substantially constant during scanning; and means for graphically displaying the spatial coordinates of said scanning tip to produce a topographical map of the surface.

Claim 3

Dependent Claim 43 words

Apparatus as set forth in claim 1 wherein said means for positioning comprises: a piezo electric drive means acting in the direction along which the separation distance between said scanning tip and the sample surface is controlled, said direction being the z direction.

Claim 4

Dependent Claim 30 words

Apparatus as set forth in claim 1 wherein said means for scanning comprises: piezo electric drive means acting in directions x and y, both being perpendicular to the z direction.

Claim 5

Dependent Claim 53 words

Apparatus as set forth in claim 3 wherein said means for graphically displaying the spatial coordinates comprises: means for graphically displaying the drive current or voltage of the z direction piezo electric drive means as a function of the drive currents or voltages of the x and y direction piezo electric drive means.

Claim 6

Dependent Claim 43 words

Apparatus as set forth in claim 2 wherein said means for automatically controlling the separation distance between said scanning tip and the sample surface comprises: a feedback system controlling said z direction piezo electric drive means in response to the measured temperature variation.

Claim 7

Dependent Claim 44 words

Apparatus as set forth in claim 2 wherein said piezo electric drive means acting in the z direction includes: means for vibrating said scanning tip transversely of the sample surface at a first frequency, whereby said scanning tip is unaffected by environmental temperature changes.

Claim 8

Dependent Claim 44 words

Apparatus as set forth in claim 6 wherein said heat source includes: a thermocouple provided at an extremity of said scanning tip; and oscillating means for directing an electrical current through said thermocouple at a second frequency which is different from said first frequency.

Claim 9

Dependent Claim 65 words

Apparatus as set forth in claim 1 wherein said scanning tip includes: a central structural element composed of conductive material and having an extreme end; a layer of dielectric material coated on said central structural element except on said extreme end; and a layer of electrically conducting material coated over said layer of dielectric material and on said extreme end of said central structural element.

Claim 10

Dependent Claim 34 words

Apparatus as set forth in claim 8 wherein: said temperature sensing means includes a thermocouple junction formed at the location at which said central structural element and said layer of electrically conducting material interface.

Claim 11

Independent Claim 134 words

A method of investigating surface structures irrespective of the materials involved comprising the steps of: applying heat to a scanning tip so that it achieves a steady state temperature when it is remote from the surface of a sample to be investigated; moving the scanning tip transversely of the sample surface to a separation distance in close proximity therewith; scanning the scanning tip across the sample surface; sensing variations in temperature of the scanning tip from the steady state temperature as the scanning step proceeds; automatically controlling the separation distance between the scanning tip and the sample surface in response to the temperature variations such that the temperature variations remain constant during the scanning step; and graphically displaying the spatial coordinates of the scanning tip to produce a topographical map of the sample surface.

Claim 12

Independent Claim 134 words

A method of investigating surface structures irrespective of the materials involved comprising the steps of: applying heat to a scanning tip so that it achieves a steady state temperature when it is remote from the surface of a sample to be investigated; moving the scanning tip transversely of the sample surface to a separation distance in close proximity therewith; scanning the scanning tip across the sample surface; sensing variations in temperature of the scanning tip from the steady state temperature as the scanning step proceeds; automatically controlling the separation distance between the scanning tip and the sample surface in response to the temperature variations such that the temperature variations remain constant during the scanning step; and graphically displaying the spatial coordinates of the scanning tip to produce a topographical map of the sample surface.

Claim 13

Dependent Claim 124 words

A method as set forth in claim 10 wherein the automatically controlling step includes the steps of: generating a first electrical signal proportional to an initial temperature variation between the steady state temperature of the scanning tip and the temperature of the scanning tip as it is initially moved to a separation distance in close proximity to the sample surface; and generating a continuing series of second electrical signals proportional to subsequent temperature variations as the scanning step proceeds; comparing each of the continuing series of second electrical signals with the first electrical signal; and continually adjusting the separation distance between the scanning tip and the sample surface such that said continuing series of second electrical signals are equal to the first electrical signal.

Claim 14

Dependent Claim 44 words

A method as set forth in claim 11 wherein the step of moving the scanning tip transversely of the sample surface is performed by a first drive means; and wherein the step of scanning the scanning tip is performed by a second drive means.

Claim 15

Dependent Claim 19 words

A method as set forth in claim 12 wherein the first and second drive means are each piezo-electric drivers.

Claim 16

Dependent Claim 54 words

A method as set forth in claim 10 wherein: the temperature of the scanning tip at the separation distance remote from the sample surface is different than the temperature of the scanning tip at the separation distance in close proximity thereto when the amount of heat applied to the scanning tip is substantially constant.

Claim 17

Dependent Claim 47 words

A method as set forth in claim 10 including the step of: oscillating the scanning tip transversely of the sample surface when the scanning tip is at a separation distance in close proximity to the sample surface, whereby the scanning tip is unaffected by environmental temperature changes.

Claim 18

Dependent Claim 44 words

A method as set forth in claim 15 wherein: the step of oscillating the scanning tip is performed at a frequency in the range of one to 10 5 hertz and at an amplitude in the range of 10 2 to 10 6 Angstroms.

Claim 19

Dependent Claim 79 words

A method as set forth in claim 10 wherein the step of applying heat to the scanning tip includes the steps of: providing a thermocouple at an extremity of the scanning tip; and directing an electrical current through the thermocouple at a frequency in the range of zero to 10 6 hertz; and wherein the step of sensing variations in temperature includes the step of: sensing variations in average temperature of the scanning tip as the scanning step proceeds.

Claim 20

Dependent Claim 82 words

A method as set forth in claim 10 including the step of: oscillating the tip transversely of the sample surface at a first frequency when the scanning tip is at a separation distance in close proximity to the sample surface; and wherein the step of applying heat to the scanning tip includes the steps of: providing a thermocouple at an extremity of the scanning tip; and directing an electrical current through the thermocouple at a second frequency different from the first frequency.

Claim 21

Dependent Claim 71 words

A method as set forth in claim 18: wherein the step of oscillating the scanning tip is performed at a first frequency in the range of one to 10 5 hertz and at an amplitude in the range of one to 10 6 Angstroms; and wherein the step of directing an electrical current through the thermocouple is performed at a second frequency in the range of zero to 10 6 hertz.

Claim 22

Dependent Claim 30 words

A method as set forth in claim 10 wherein the step of applying heat to the scanning tip includes the step of: directing a laser beam at the scanning tip.

Claim 23

Dependent Claim 61 words

A method as set forth in claim 20: wherein the step of directing a laser beam at the sensing tip is performed at a frequency in the range of zero to 10 6 hertz; and wherein the step of sensing variations in temperature includes the step of sensing variations in average temperature of the scanning tip as the scanning step proceeds.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1991-05-31	1991-11-30	1992-05-31	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1995-05-31	1995-11-30	1996-05-31	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1999-05-31	1999-11-30	2000-05-31	$7700.00	Window Closed / Lapsed

Scanning thermal profiler

Abstract

Inventors

Bibliographic Details

Claims Analysis

References Cited (Backward Citations)

USPTO Annuity & Maintenance Windows

Assigned Categories & Tags

Assign Category Tag