CN1670505A - A multi-mode atomic force probe scanning system - Google Patents

Abstract

This invention discloses one multi-mode atomic force detector scanning system, which comprises optical measurement unit, scanning and detecting unit and servo control unit wherein, the said scanning and detecting unit comprises the scanning bench driven by servo control unit, micro-adjusting structure, piezoelectricity double transistor pads located on the structure, micro hanging detecting needle relatively located on the detecting end and with ends fixed on transistors; the said hanging back is located on the light detector focus and is vertical to eh detector axis line; the said piezoelectricity pad is controlled by servo control unit and the driving hanging detector works by one mode of contacting one, non-contacting and taping one.

Description

A kind of multiple-pattern atomic force probe scanning system

Technical field

The invention belongs to Nanosurface detection technique field, particularly a kind of multiple-pattern atomic force probe scanning system that can carry out high resolving power large-scale nano level surfaceness, percent ripple and surface damage detection.

Background technology

The high integration of electronic product and the development trend of high performance, detection has proposed unprecedented specific (special) requirements to parts surface, as requiring disc or wafer surface detection can reach the nanoscale surface precision, dust level surface waviness and roughness can detect whole disc again simultaneously.Traditional optical detective technology detects for roughness can reach the dust class resolution ratio.These detection techniques have laser interferance method, ellipsometry, scattering method etc.But owing to limited by the Rayleigh diffraction limit, lateral resolution is that the traditional light probe of restriction carries out the bottleneck that the nanometer scale superfinish detects.On the other hand, scanning tunnel microscope (STM) can both reach nano-precision with vertical, the lateral resolution that atomic force microscope (AFM) detects the surface.But their measurement range is very little, generally has only several microns to tens microns.

Summary of the invention

The object of the present invention is to provide a kind of multiple-pattern atomic force probe scanning system, realize that high resolving power large-scale nano scale surface roughness, percent ripple and surface damage detect.

For the requirement that can satisfy high resolving power simultaneously and detect on a large scale, multiple-pattern atomic force probe scanning system of the present invention adopts solid micro-cantilever probe to carry out the surface and detects, and makes lateral resolution reach nanoscale; And the axial deflection amount by low frequency differences two-frequency laser interferometer detection micro-cantilever probe makes longitudinal frame can reach the dust class precision.On the other hand, adopt large area scanning platform and image mosaic and recognition technology, realized the surface of whole CD, disk or wafer is detected.

Technical scheme of the present invention is as follows:

A kind of multiple-pattern atomic force probe scanning system, it is characterized in that: described system comprises optical measurement unit, scanning probe unit and three parts of servo control unit, described scanning probe unit comprises being subjected to scan table, micro-adjusting mechanism that servo control unit drives, being located at the piezoelectric bimorph on the described micro-adjusting mechanism of carrying sample, and terminally be fixed on the piezoelectric bimorph, micro-cantilever probe that the end of probe counter sample is provided with; The described micro-cantilever probe back side is in the light probe convergent point place of described optical measurement unit, and perpendicular with the light probe axis; Described piezoelectric bimorph is controlled by servo control unit, drives the micro-cantilever probe with contact, contactless or rap one of three kinds of patterns of formula and survey.

In the present invention: described optical measurement unit comprises transverse zeeman laser, is positioned at beam splitter, negative lens, birefringent lens, infinite tube length microcobjective, the reference mirror of described transverse zeeman laser front end along optical axis direction successively, and corresponding with described beam splitter, be arranged vertically along optical axis direction, and receive the output of transverse zeeman laser afterbody reference signal photodetector.

In the present invention, described micro-adjusting mechanism comprises that support plinth, lower end fixedly connected with support plinth, the upper end is connected support plinth and web joint with the fixedly connected tilt stand of web joint, respectively from both sides right bank adjusts screw and left bank adjustment screw, be fixed in pitching support on the web joint, be connected the pitching adjustment screw of pitching support and web joint, and with voussoir, piezoelectric bimorph and the micro-cantilever probe stationary spring leaf in pitching support front end groove; Tilt stand and pitching support adopt flexure hinge mechanism, realize the adjustment of micro-cantilever probe degree of tilt and pitching degree.

The present invention adopts double frequency difference interference technology, detect that the micro-cantilever probe is subjected to faint atomic force effect and the axial deflection amount that takes place, and make the micro-cantilever probe stationary motionless, scan table drives sample and makes relative scanning, thereby obtain the three-dimensional appearance of sample surfaces, and and then obtain the variable of surfaceness, percent ripple and surface damage.Adopting the advantage of double frequency difference interference technology is that it is insensitive for the micro-cantilever cross torsion that tangential force causes, thereby has eliminated the error that the micro-cantilever cross torsion is brought.Therefore, with respect to traditional atomic force microscope, measuring resolution of the present invention and precision have improved an order of magnitude.The present invention can work in contact, contactless and rap under three kinds of patterns of formula.In addition, the present invention takes horizontal type structure, can avoid effectively the micro-cantilever probe from gravity to atomic influence.Present invention is directed at super fine surface roughness, percent ripple and surface damage and detect and design, also be applicable to the accurate detection of conductor, semiconductor and insulator sample surfaces simultaneously.

Description of drawings

Fig. 1 is the structural representation of multiple-pattern atomic force probe scanning system of the present invention.

Fig. 2 a is the front view of the micro-adjusting mechanism of micro-cantilever probe.

Fig. 2 b is the left view of Fig. 2 a.

Embodiment

Further specify the present invention below in conjunction with accompanying drawing.

As shown in Figure 1, the present invention includesoptical measurement unit 100,scanning probe unit 200 and servo control unit 300.Whereinoptical measurement unit 100 comprisestransverse zeeman laser 1, is positioned atbeam splitter 5, negative lens 6, birefringent lens 7, infinitetube length microcobjective 8, the reference mirror 9 oftransverse zeeman laser 1 front end along optical axis direction successively, and 5 corresponding with beam splitter, be arranged vertically along optical axis direction, and receive thephotodetector 10 of the reference signal oftransverse zeeman laser 1 afterbody output;Transverse zeeman laser 1 vacuum wavelength ofoptical measurement unit 100 is 632.99nm, and beam diameter is 6mm, and laser instrument is output as two bundle orhtogonal linear polarizaiton light (being o light and e light).In the present embodiment, betweentransverse zeeman laser 1 andbeam splitter 5, also be provided withlenslet 2, pin hole 3 and cementeddoublet 4 successively, strengthen the signal to noise ratio (S/N ratio) of optical signalling, more effectively realize light path adjusting and filtering along optical axis direction.

Negative lens 6 front and back radius-of-curvature in theoptical measurement unit 100 are respectively 252.73 and 79.32mm, thickness 2.3mm, and material is ZF1, is used to enlarge measurement range, improves measuring accuracy; Birefringent lens 7 materials are respectively ZF1 and calcite crystal, and thickness is 1.6mm, are used for the laser beam spacing shaping, change transmittance function.

In the course of work, the orhtogonal linear polarizaiton light oftransverse zeeman laser 1 output impinges perpendicularly onlenslet 2, converges on the pin hole 3, by cementeddoublet 4 light beam is expanded into parallel beam after pin hole 3 filtering; Parallel beam incides on the birefringent lens 7 bybeam splitter 5, negative lens 6, and 7 pairs of polarization directions of birefringent lens light parallel with its optical axis direction has converging action, is infinitely great to the polarization direction light focal length vertical with optical axis.Because birefringent lens 7 optical axis directions are identical with the e light polarization direction, therefore through behind the birefringent lens 7, o light still is directional light, and e light becomes converging light; Then, two-beam is by thelong microcobjective 8 of infinite letter.Infinitetube length microcobjective 8 front focus overlap with the e optical focus, so original parallel o light becomes converging light, form light probe, focus on the back side of the micro-cantilever probe 21 (describing hereinafter) ofscanning probe unit 200, as the measuring light of optical measurement unit; Originally the e light of Hui Juing becomes directional light, impinges upon on the reference mirror 9 to justify hot spot, as the reference light of optical measurement unit.Measuring light and reference light are respectively by after micro-cantilever probe and the reference mirror reflection, successively byobject lens 8, birefringent lens 7, negative lens 6, become the parallel beam that overlaps again, reflexed tophotodetector 10 bybeam splitter 5, produce the optical measurement phase signal, carry out than mutually with the reference signal oftransverse zeeman laser 1 afterbody output, analog to digital conversion circuit (A/D) 33 (describing hereinafter) byservo control unit 300, phase data is input in the microcomputer 31 (describing hereinafter), just can obtains the micro-cantilever probe shaft to amount of deflection (along the optical axis direction of light path among Fig. 1) through data processing.

Scanning probe unit 200 is subjected to scan table 24,micro-adjusting mechanism 23 thatservo control unit 300 drives, is located at the piezoelectric bimorph 22 on the describedmicro-adjusting mechanism 23 by the carrying sample, and terminally be fixed on the piezoelectric bimorph 22, micro-cantilever probe 21 that the end of probe counter sample is provided with forms; Wherein micro-cantilever probe 21 back sides are in the light probe convergent point place of describedoptical measurement unit 100, and perpendicular with the light probe axis; Piezoelectric bimorph 22 is byservo control unit 300 control, drives micro-cantilever probe 21 with contact, contactless or rap one of three kinds of patterns of formula and survey.Scan table 24 is realized the longitudinal pitch adjustment and the transversal scanning of sample and micro-cantilever probe (21) by the D/A converting circuit in theservo control unit 300 32 (describing hereinafter) control.

In the scanning process, keep micro-cantilever probe 21 to maintain static, at first pass through D/A converting circuit (A/D) the 32gated sweep platforms 24 ofservo control unit 300, make sample approach micro-cantilever probe 21 along the optical axis direction ofoptical measurement unit 100, until will producing faint atomic force between the two, and make micro-cantilever probe 21 produce the axial deflection amounts.Then, byservo control unit 300gated sweep platforms 24, and drive sample in surface level (transversal scanning, comprise X to Y to) motion scan.Optical measurement unit 100 obtains the axial deflection amount information that micro-cantilever probe 21 forms in the scanning process, and the sample levels positional information of scan table 24 transversal scanning generation, and above-mentioned information feedback carried out data processing in themicrocomputer 31 ofservo control unit 300, thereby obtain performance index such as sample surfaces three-dimensional appearance and surfaceness, percent ripple, little cut, micro-crack.

21 pairs of sample measurements of the micro-cantilever probe ofscanning probe unit 200 have contact, contactless and rap three kinds of patterns of formula.When contact mode was measured, micro-cantilever probe 21 needle points were all the time with sample contact and slip from the teeth outwards simply.The micro-cantilever probe is owing to being deflected by the effect of sample surfaces coulomb repulsion power, and the axial deflection amount promptly is the surface undulation variable quantity.When noncontact mode was measured, micro-cantilever probe 21 separated with sample surfaces, and was subjected to the excitation of piezoelectric bimorph 22 to produce vibration.The amplitude of excited vibration becomes with micro-cantilever probe 21 needle points and sample interval, and is controlled by theservo feedback circuit 35 ofservo control unit 300, thereby keeps the invariable of micro-cantilever probe 21 and sample interval.The oscillation amplitude change amount is the surface undulation variable quantity of detected sample, i.e. surface topography.When the pattern of rapping was measured, micro-cantilever probe 21 rapped sample surfaces, andservo feedback circuit 35 controls byservo control unit 300, kept the power of rapping to be in minimum value, promptly micro-cantilever probe 21 and sample rigidly connect touch but mutually impact almost do not have.Amplitude changed after micro-cantilever probe 21 was subjected to the effect of sample surfaces atomic force, and the oscillation amplitude change amount promptly is the variable quantity of surface undulation.

Servo control unit 300 is similar with servocontrol part of the prior art, the analog to digital conversion circuit (A/D) 33 that comprises D/A converting circuit (D/A) 32, connectionphase lock circuitry 34 and the describedphotodetector 10 ofmicrocomputer 31, drivensweep platform 24, and input links to each other theservo feedback circuit 35 of output control piezoelectric bimorph 22 with phase lock circuitry 34.Servocontrol unit 300 is used to gather the phase signal thatoptical measurement unit 100 produces, and the micro-cantilever probe 21 of servocontrolscanning probe unit 200 and scan table 24.

Fig. 2 a and Fig. 2 b have shown the composition structure of micro-adjusting mechanism 23.Micro-adjusting mechanism 23 comprises that support plinth 401, tilt stand 402, web joint 403, right bank are adjusted screw 404, left bank is adjusted screw 405, connecting screw 406, pitching support 407, pitching adjustment screw 408, spring leaf 409 and voussoir 410.Support plinth 401 is used formicro-adjusting mechanism 23 andoptical measurement unit 100 are fixed in identical platform.Left and right tilt adjustments screw 405 is connected with support plinth 401 web joint 403 from and arranged on left and right sides with 404; Adopt flexure hinge mechanism in the middle of the tilt stand 402, web joint 403 is connected with support plinth 401, the adjustment of left and right tilt adjustments screw can realize the 21 degree of tilt adjustment of micro-cantilever probe.Pitching is adjusted screw 408 and by screw thread pitching support 407 is connected with web joint 403; Pitching support 407 adopts flexure hinge mechanism, adjusts pitching adjustment screw 408 and can drive the rotation of pitching support 407 front ends, realizes the adjustment of pitching degree thereby drive micro-cantilever probe 21.Micro-cantilever probe 21, voussoir 410, piezoelectric bimorph 22 are fixed in the front end groove of pitching support 407 together by spring leaf 409.Micro-adjusting mechanism 23 assemblesoptical measurement unit 100 formed light probes by micro-cantilever probe 21 degree of tilt and pitching degree are adjusted, and perpendicular to micro-cantilever probe 21 back sides, guarantees that the reflected light original optical path returns.

Claims (3)

Translated fromChinese

1.一种多模式原子力探针扫描系统，其特征在于：所述系统包括光学测量单元(100)、扫描探测单元(200)和伺服控制单元(300)三个部分，所述扫描探测单元(200)包括承载样品的受伺服控制单元(300)驱动的扫描台(24)、微调机构(23)、设在所述微调机构(23)之上的压电双晶片(22)，以及末端固定在压电双晶片(22)上、探测端对应样品设置的微悬臂探针(21)；所述微悬臂探针(21)背面处于所述光学测量单元(100)的光探针会聚点处，并与光探针轴线相垂直；所述压电双晶片(22)由伺服控制单元(300)控制，驱动微悬臂探针(21)以接触式、非接触式或轻敲式三种模式之一进行探测。1. A multi-mode atomic force probe scanning system is characterized in that: the system comprises three parts of an optical measurement unit (100), a scanning detection unit (200) and a servo control unit (300), and the scanning detection unit ( 200) comprising a scanning stage (24) driven by a servo control unit (300) carrying a sample, a fine-tuning mechanism (23), a piezoelectric bimorph (22) arranged on the fine-tuning mechanism (23), and an end-fixed On the piezoelectric bimorph (22), the micro-cantilever probe (21) whose detection end corresponds to the sample setting; the back side of the micro-cantilever probe (21) is at the optical probe convergence point of the optical measurement unit (100) , and perpendicular to the optical probe axis; the piezoelectric bimorph (22) is controlled by a servo control unit (300) to drive the micro-cantilever probe (21) in three modes: contact, non-contact or tap One of them is detected.2.根据权利要求1所述的多模式原子力探针扫描系统，其特征在于：所述光学测量单元(100)包括横向塞曼激光器(1)、沿光轴方向依次位于所述横向塞曼激光器(1)前端的分束器(5)、负透镜(6)、双折射透镜(7)、无穷筒长显微物镜(8)、参考镜(9)，以及与所述分束器(5)对应、沿光轴方向垂直布置，并且接收横向塞曼激光器(1)尾部输出的参考信号的光电探测器(10)。2. The multi-mode atomic force probe scanning system according to claim 1, characterized in that: the optical measurement unit (100) comprises a transverse Zeeman laser (1), and the transverse Zeeman laser is sequentially positioned along the optical axis direction (1) beam splitter (5), negative lens (6), birefringent lens (7), infinite tube long microscope objective lens (8), reference mirror (9) at the front end, and the beam splitter (5) ) corresponds to a photodetector (10) that is arranged vertically along the optical axis and receives a reference signal output from the tail of the transverse Zeeman laser (1).3.根据权利要求1所述的多模式原子力探针扫描系统，其特征在于：所述微调机构(23)包括支承底座(401)、下端与支承底座(401)固定连接，上端与连接板(403)固定连接的倾斜支架(402)、分别从两侧连接支承底座(401)和连接板(403)的右倾斜调整螺丝(404)和左倾斜调整螺丝(405)、固定于连接板(403)上的俯仰支架(407)、连接俯仰支架(407)和连接板(403)的俯仰调整螺丝(408)，以及将楔块(410)、压电双晶片(22)和微悬臂探针(21)固定在俯仰支架(407)前端凹槽内的弹簧片(409)；倾斜支架(402)和俯仰支架(407)采用柔性铰链机构，实现微悬臂探针(21)倾斜度与俯仰度调整。3. The multi-mode atomic force probe scanning system according to claim 1, characterized in that: the fine-tuning mechanism (23) includes a support base (401), the lower end is fixedly connected with the support base (401), and the upper end is connected with the connecting plate ( 403) fixedly connected inclined bracket (402), the right inclined adjustment screw (404) and the left inclined adjustment screw (405) connecting the support base (401) and the connecting plate (403) from both sides respectively, fixed on the connecting plate (403 ) on the pitch support (407), the pitch adjustment screw (408) connecting the pitch support (407) and the connecting plate (403), and the wedge (410), the piezoelectric bimorph (22) and the microcantilever probe ( 21) The spring leaf (409) fixed in the groove at the front end of the pitch bracket (407); the tilt bracket (402) and the pitch bracket (407) adopt a flexible hinge mechanism to realize the adjustment of the inclination and pitch of the micro-cantilever probe (21) .

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