Synchronous sampling scanning force microscope

Claim 2

In a synchronous sampling scanning force microscope for examining surface contours of a specimen, said specimen surface also having an attractive region and a repulsive region, said microscope having a body, a cantilever arm having a first end secured to said body and a free end, said cantilever arm having a fundamental resonance frequency, probe means secured to said free end of said cantilever arm and including a probe tip adapted to follow surface contours of the specimen, scanning means for mounting said specimen for examination by said microscope and adapted to scan said specimen relative to said body, deflection measuring means mounted to said body for measuring deflection of the cantilever arm and generating a deflection signal indicative of deflection of said cantilever arm, the improvement which comprises: oscillator drive means connected to said cantilever arm for causing the cantilever arm and probe tip to oscillate toward and away from said specimen surface contours at a desired frequency in cycles of near and far excursions of said probe tip relative to said specimen surface; sampling means for sampling selected portions of cycles of said deflection signal corresponding to said cycles of near and far excursions of said probe tip and for generating output signal data indicative of elevation of said surface contours of said specimen; phase control means connected to said deflection measuring means for receiving said deflection signals, said phase control means being connected to said sampling means for controlling the sampling of said selected portions of cycles of said deflection signal; and means for storing said output signal data.

Claim 3

The microscope of claim 1, wherein said desired frequency of oscillation is different from the resonant frequency of the cantilever arm.

Claim 4

The microscope of claim 1, wherein said desired frequency of oscillation is a frequency less than the resonant frequency.

Claim 5

The microscope of claim 1, wherein said desired frequency of oscillation is a frequency between about 5-500 kHz.

Claim 6

The microscope of claim 1, wherein said desired frequency of oscillation is a frequency between about 80-250 kHz.

Claim 7

The microscope of claim 1, wherein said oscillator drive means is operative to drive said cantilever arm with an oscillation amplitude between about 2Å and 1000Å.

Claim 8

The microscope of claim 1, wherein said oscillator drive means is operative to drive said cantilever arm with an oscillation amplitude between about 100Å and 1000Å at about 50-100 kHz.

Claim 9

The microscope of claim 1, wherein said oscillator drive means is operative to drive said cantilever arm with an oscillation amplitude between about 2Å and 10Å at about 5-500 kHz.

Claim 10

The microscope of claim 1, wherein said sampling means is operative to sample measurements of amplitude of oscillation of said cantilever arm.

Claim 11

The microscope of claim 1, wherein said sampling means is operative to sample measurements of phase shift of oscillation of said cantilever arm.

Claim 12

The microscope of claim 1, further including probe position control feedback means for maintaining the probe in the attractive region of the specimen surface.

Claim 13

The microscope of claim 1, further including probe position control feedback means for maintaining the probe in intermittent contact with a contamination layer on the specimen surface.

Claim 14

The microscope of claim 1, wherein said sampling means includes means for sampling at a plurality of times during each cycle.

Claim 15

The microscope of claim 1, wherein said sampling means includes means for sampling at intervals of 90° and 270° phases of each cycle.

Claim 16

The microscope of claim 1, wherein said sampling means includes means for determining said output signal data as a difference between measured amplitude at 90° and 270°.

Claim 17

The microscope of claim 1, further including display means connected to said means for storing, for displaying an image of the surface of the specimen based upon said output signal data.

Claim 18

The microscope of claim 1, further including means for averaging successive output signal data to generate an image.

Claim 19

The microscope of claim 17, wherein said means for averaging comprises means for averaging a root mean square of voltage of said output signal data.

Claim 20

The microscope of claim 17, wherein said means for averaging comprises means for averaging output signal data of a plurality of images of the surface contours of a specimen.

Claim 21

The microscope of claim 1, wherein said sampling means includes means for generating a position feedback signal for positioning the probe tip a desired distance from the surface of the specimen.

Claim 22

A synchronous sampling scanning force microscope for examining surface contours of a specimen, said specimen surface also having an attractive region and a repulsive region, the microscope comprising: a body, said body including a cantilever arm having a first end secured to said body and a free end, said cantilever arm having a fundamental resonance frequency; probe means secured to said free end of said cantilever arm, said probe means including a probe tip adapted to follow the surface contours of the specimen with a substantially constant amount of force; scanning means for mounting said specimen for examination by said microscope and adapted to scan said specimen relative to said body; deflection measuring means for measuring motion of said cantilever arm and for generating an output signal indicative of an amount of deflection of said cantilever arm means; oscillator drive means connected to said cantilever arm for causing the cantilever arm and probe tip to oscillate toward and away from said specimen surface contours at a desired frequency in cycles of near and far excursions of said probe tip relative to said specimen surface; sampling means for sampling selected portions of cycles of said deflection signal corresponding to said cycles of near and far excursions of said probe tip and for generating output signals indicative of elevation of said surface contours of said specimen; phase control means connected to said deflection measuring means for receiving said deflection signal and connected to said sampling means for controlling the sampling of said selected portions of cycles of said deflection signal; and memory means for storing said output signals.

Claim 23

A synchronous sampling scanning force microscope for examining surface contours of a specimen, said specimen surface also having an attractive region and a repulsive region, the microscope comprising: a body, said body including a cantilever arm having a first end secured to said body and a free end, said cantilever arm having a fundamental resonance frequency; probe means secured to said free end of said cantilever arm, said probe means including a probe tip adapted to follow the surface contours of the specimen with a substantially constant amount of force; scanning means for mounting said specimen for examination by said microscope and adapted to scan said specimen relative to said body; deflection measuring means for measuring motion of said cantilever arm and for generating an output signal indicative of an amount of deflection of said cantilever arm means; oscillator drive means connected to said cantilever arm for causing the cantilever arm and probe tip to oscillate toward and away from said specimen surface contours at a desired frequency in cycles of near and far excursions of said probe tip relative to said specimen surface; sampling means for sampling selected portions of cycles of said deflection signal corresponding to said cycles of near and far excursions of said probe tip and for generating output signals indicative of elevation of said surface contours of said specimen; phase control means connected to said deflection measuring means for receiving said deflection signal and connected to said sampling means for controlling the sampling of said selected portions of cycles of said deflection signal; and memory means for storing said output signals.

Claim 24

The microscope of claim 21, wherein said means for measuring motion of said oscillating cantilever arm comprises laser light source means mounted to said body for producing a focused laser beam directed at and deflected by said cantilever arm, and photodetector means mounted to said body for receiving said laser beam deflected by said cantilever arm and generating said output signals.

Claim 25

The microscope of claim 21, wherein said desired frequency of oscillation is a frequency different from the resonant frequency of the cantilever arm.

Claim 26

The microscope of claim 21, wherein said desired frequency of oscillation is a frequency less than the resonant frequency.

Claim 27

The microscope of claim 21, wherein said desired frequency of oscillation is a frequency between about 5-500 kHz.

Claim 28

The microscope of claim 21, wherein said desired frequency of oscillation is frequency between about 80-250 kHz.

Claim 29

The microscope of claim 21, wherein said oscillator drive means is operative to drive said cantilever arm with an oscillation amplitude between about 2Å and 1000Å.

Claim 30

The microscope of claim 21, wherein said oscillator drive means is operative to drive said cantilever arm with an oscillation amplitude between about 100Å and 1000Å at about 50-100 kHz.

Claim 31

The microscope of claim 21, wherein said oscillator drive means is operative to drive said cantilever arm with an oscillation amplitude between about 2Å and 10Å at about 5-500 kHz.

Claim 32

The microscope of claim 21, wherein said sampling means includes means for sampling amplitude of oscillation of said cantilever arm.

Claim 33

The microscope of claim 21, wherein said sampling means includes means for sampling phase shift of oscillation of said cantilever arm.

Claim 34

The microscope of claim 21, wherein said sampling means includes dual sample and hold amplifiers.

Claim 35

The microscope of claim 21, wherein said sampling means includes a plurality of sample and hold amplifiers.

Claim 36

The microscope of claim 21, wherein said sampling means includes probe position control feedback means for maintaining the probe in the attractive region of the specimen surface.

Claim 37

The microscope of claim 21, wherein said sampling means includes probe position control feedback means for maintaining the probe in intermittent contact with a contamination layer on the specimen surface.

Claim 38

The microscope of claim 21, wherein said sampling means includes clock output means.

Claim 39

The microscope of claim 21, further including display means for displaying an image of the surface of the specimen based upon said output signals.

Claim 42

The method of claim 38, wherein said step of oscillating said free end of said cantilever arm comprises oscillating the cantilever arm at a frequency between about 5-500 kHz.

Claim 43

The method of claim 38, wherein said step of oscillating said free end of said cantilever arm comprises oscillating the cantilever arm at a frequency between about 80-250 kHz.

Claim 44

The method of claim 38, wherein said step of oscillating said free end of said cantilever arm comprises driving oscillations of the cantilever arm at an amplitude between about 2Å and 1000Å.

Claim 45

The method of claim 38, wherein said step of oscillating said free end of said cantilever arm comprises driving oscillations of the cantilever arm at an amplitude between about 100Å and 1000Å at about 50-100 kHz.

Claim 46

The method of claim 38, wherein said step of oscillating said free end of said cantilever arm comprises driving oscillations of the cantilever arm at an amplitude between about 2Å and 10Å at about 5-500 kHz.

Claim 47

The method of claim 38, wherein said step of sampling selected portions of cycles of said deflection signal comprises sampling amplitude of said deflection signal.

Claim 48

The method of claim 38, wherein said step of sampling selected portions of cycles of said deflection signal comprises sampling phase shift of said deflection signal.

Claim 49

The method of claim 38, wherein said step of sampling selected portions of cycles of said deflection signal comprises sampling amplitude of said deflection signal for about 10% of the period of each cycle.

Claim 50

The method of claim 38, wherein said step of sampling selected portions of cycles of said deflection signal comprises sampling amplitude of said deflection signal at a plurality of times during each cycle.

Claim 51

The method of claim 38, wherein said step of sampling selected portions of cycles of said output signal comprises sampling amplitude of said deflection signal at intervals of 90° and 270° phases of each cycle.

Claim 52

The method of claim 38, wherein said output signal data is determined as the difference between measured amplitude at 90° and 270°.

Claim 53

The method of claim 38, further including the step of averaging successive output signal data to generate topographical data for displaying said image.

Claim 54

The method of claim 38, further including the step of averaging the root mean square of said output signal data to generate topographical data for displaying said image.

Claim 55

The method of claim 38, further including the step of averaging output signal data of a plurality of images on a pixel by pixel basis to generate topographical data for displaying an averaged image of said surface contours of specimen.

Claim 56

The method of claim 38, further including the step of generating a position feedback signal based upon said deflection signal for positioning the probe tip a desired distance from the surface of the specimen.

Claim 57

The method of claim 38, further including the step of generating a probe position feedback signal based upon said deflection signal for maintaining the probe in an attractive region of the specimen surface.

Claim 58

The method of claim 38, further including the step of generating a probe position feedback signal based upon said deflection signal for maintaining the probe in intermittent contact with a contamination layer on the specimen surface.

Claim 59

In a scanning force microscope for examining surface contours of a specimen, said microscope having a body, a deflection arm having a first end secured to said body and a free end, said deflection arm having a fundamental resonance frequency, probe means secured to said free end of said deflection arm and including a probe tip adapted to follow the surface contours of the specimen, scanning means for mounting said specimen for examination by said microscope and adapted to scan said specimen relative to said body, and deflection measuring means mounted to said body for measuring motion of the deflection arm and generating a deflection signal indicative of deflection of said deflection arm, the improvement which comprises: oscillator drive means connected to said deflection arm for causing deflection arm and the probe tip to oscillate toward and away from said specimen surface contours at a desired frequency in cycles of near and far excursions of said probe tip relative to said specimen surface; sampling means for sampling selected portions of cycles of said output signal corresponding to said cycles of near and far excursions of said probe tip and for generating output signals representing deflection of said near and far excursions of said probe tip at said selected portions of said cycles; control means connected to said deflection measuring means for receiving said deflection signal and connected to said sampling means for controlling the sampling of said selected portions of cycles of said deflection signal; and means for storing said output signals.

Claim 60

In a scanning force microscope for examining surface contours of a specimen, said microscope having a body, a deflection arm having a first end secured to said body and a free end, said deflection arm having a fundamental resonance frequency, probe means secured to said free end of said deflection arm and including a probe tip adapted to follow the surface contours of the specimen, scanning means for mounting said specimen for examination by said microscope and adapted to scan said specimen relative to said body, and deflection measuring means mounted to said body for measuring motion of the deflection arm and generating a deflection signal indicative of deflection of said deflection arm, the improvement which comprises: oscillator drive means connected to said deflection arm for causing deflection arm and the probe tip to oscillate toward and away from said specimen surface contours at a desired frequency in cycles of near and far excursions of said probe tip relative to said specimen surface; sampling means for sampling selected portions of cycles of said output signal corresponding to said cycles of near and far excursions of said probe tip and for generating output signals representing deflection of said near and far excursions of said probe tip at said selected portions of said cycles; control means connected to said deflection measuring means for receiving said deflection signal and connected to said sampling means for controlling the sampling of said selected portions of cycles of said deflection signal; and means for storing said output signals.