CN101246122B - Ellipsometry imaging method and device adopting rotating compensator integration sampling - Google Patents

Abstract

The invention relates to an ellipsometric imaging method and device using a rotary compensator and time integral sampling. The method includes the following steps: setting the system; performing time integral exposure on the image sensor; converting, transmitting, processing and storing the data; and calculating the collected data. The device includes: an incident unit; an exit unit; a data collection and processing unit; the data collection and processing unit triggers the exit unit to obtain the ellipsometric image of the sample through a hard trigger. The invention uses the time integration method to sample, which greatly improves the time resolution of the system, that is, reduces the sampling time; adopts the uniform-speed rotating phase compensator to achieve the purpose of stability, and can ensure the control precision.

Description

Adopt the ellipsometry imaging method and the device of rotating compensator integration sampling

Technical field

The present invention relates to a kind of to surface and film sample, especially nano thin-film is carried out the ellipsometry imaging measuring method and the device of fast characterizing, be particularly related to the sampling of a kind of employing whirl compensator and time integral, ellipsometry imaging method and device that the each point on nano film material surface with complicated transversary is measured simultaneously fast.

Background technology

Ellipse partially (elliptically polarized light) imaging technique is a kind of novel large-area nano film characterizing method of development in recent years, can be used for the measurement of nano thin-film practicability material such as artificial membrane, novel sensor, SIC (semiconductor integrated circuit), light quantum device, biochip, high density storage and surface device.This technology is on the basis of traditional single-point ellipsometry technology, combine micro-imaging technique and digital image acquisition treatment technology (the list of references 1:Harland G.Tompkins and Eugene A.Irene that grows up, Handbook of ellipsometry, New York:William Andrew Inc., 2005).It utilizes light wave at sample surfaces generation reflex time, the characteristic that the polarization state of detection light wave is changed by the modulation of sample, by variation and effective physical model of polarization state before and after the reflection of detection light wave, information such as the refractive index of acquisition sample, absorption coefficient, thickness.Even have only the film of nano thickness on the solid surface, also can cause the marked change of polarization state.So this technology has high detection sensitivity, the parsing level of thickness can reach the atomic layer magnitude.Owing to have micro-imaging technique, so can obtain the information of each point on the large-area planar sample, lateral resolution can reach the level of optical diffraction limit.This technology has obtained important use (list of references 2:Danny van Noort in fields such as non-mark protein chip, biomolecule detection, the analyses of microcell surface physical property, Jens Rumberg, Edwin W H Jager and CarlFredrikMandenius, Silicon based affinity biochips viewed with imagingellipsometry, Meas.Sci. Technol.2000,11:801-808; List of references 3:Jin G, Wang ZH, Micro-systems for optical protein-chip, International journal of nonlinearsciences and numerical simulation, 2002,3:191-194).

In the ellipsometry imaging system, in order to obtain the character of sample (surface sample or film), developed the multiple method of sampling, comprise zero ellipse folk prescription method (list of references 4:Teruhito Mishima, Kwan C.Kao, Detection of thickness uniformity of film layers insemiconductor devices by spatially resolved ellipsointerferometry, OpticalEngineering, 1074-1078), rotatory polarization device method (list of references 5:A.Albersd 1982,21 (6):

Rfer, G.Elender, G.Mathe, K.R.Neumaier, P.Paduschek and E.Sackmann, High resolution imaging microellipsometry of soft surfaces at 3mm lateral and 5

Normal resolution, Applied physics Letters, 1998,72 (23): 2930-2932; List of references 6:D.Beaglehole, Performance of a microscopicimaging ellipsometer, Rev.Sci.Instrum., 1988,59 (12): 2557-2559), phase modulating method (list of references 7:Chieh-Yuan Han and Yu-Faye Chao, Photoelasticmodulated imaging ellipsometry by stroboscopic illumination technique, Rev.Sci.Instrum., 2006,77:023107-1-5), non-extinction method (list of references 8:GangJin, Roger Jansson, and Hans Arwin, Imaging ellipsometry revisited:Developments for visualization of thintransparent layers on silicon substrates, Rev.Sci.Instrum., 1996,67 (8): 2930-2936), colored real-time method (list of references 9:Adachi, Eiki; Yoshimura, Hideyuki; Nagayama, Kuniaki Color ellipsoscopefor real-time imaging of nanometer-scale surface phenomena, Applied Optics, 1995,34 (4): 729-731) etc.Wherein, rotatory polarization device method is used comparatively general, whirl compensator method wherein can be carried out the measurement of high precision high accuracy to low polarization state, can determine the symbol of ellipse drift angle Δ, and the influence that can abatement device by the polarization sensitivity of light source polarization state or light-detecting device measurement result be produced during rotation.The whirl compensator method has become a kind of important nano thin-film detection method at present.

The basic optical structure that adopts the whirl compensator method to carry out the ellipsometry imaging of ellipsometry is the polarizer-whirl compensator-sample-analyzer (P-rC-S-A) structure, perhaps the polarizer-sample-compensator-analyzer structure (P-S-rC-A) structure.Utilize Stokes vector and Muller matrix that system is carried out the ellipsometry analysis, the form that can obtain the light intensity signal that obtains on arbitrary pixel on the image is (list of references 1:Harland G.Tompkins and Eugene A.Irene, Handbook of ellipsometry, New York:William Andrew Inc., 2005)

I(C)＝I ₀(1+α ₂′cos2C+β ₂′sin2C+α ₄′cos4C+β ₄′sin4C) (1)

Wherein, I ₀DC component for signal, C is the position angle of compensator, and other each coefficient is the function of systematic parameter (polarizer position angle P, analyzer position angle A, compensator phase-delay difference δ etc.) and sample parameters (ellipsometric parameter ψ and Δ) etc., wherein, ellipsometric parameter is defined as:

$\tan \mathrm{\ψ}*e^{\mathrm{j\Δ}}=\frac{R_p}{R_s}$

Wherein, R _pAnd R _sExpression is parallel to the p light wave of the plane of incidence and perpendicular to the complex reflection coefficient of the s light wave of the plane of incidence respectively.

In the whirl compensator method, measure series of equations by the position angle that changes compensator exactly, obtain each coefficient in the formula (1) by equation, that utilizes each coefficient and ellipsometric parameter (ψ and Δ) again concerns the recursion ellipsometric parameter.In conjunction with the physical model of sample, from ellipsometric parameter, the physical parameter of sample (as refractive index, extinction coefficient, thicknesses of layers etc.) is parsed then.

In the whirl compensator elliptical polarization measuring system of spot measurement, the sampling time of sampling device (as silicon detector) extremely short (being generally nanosecond) to the microsecond magnitude.During sampling, compensator at the uniform velocity rotates, and samples on the compensator position angle of appointment, can realize higher sample rate.But in the ellipsometry imaging system, because the imageing sensor (charge coupled device ccd that is adopted, complementary metal oxide semiconductor (CMOS) CMOS) is photon time integral device, obtaining piece image need be through integration exposure and two time period that are linked in sequence of data transmission, generally more than millisecond.Therefore, if adopt the method for continuous whirl compensator, bigger azimuth angle error can appear.In order to adapt to these characteristics of imageing sensor, the method that adopts is a multi-point sampling at present.Basic step is:

(a) the fixing position angle of the polarizer and analyzer;

(b) one-period of compensator (180 °) is divided into N equal angular interval;

(c) universal stage is started from scratch and is accelerated to a certain angular velocity omega, stops at the compensator position angle after moving the speed that decelerates to again after a period of time then and be 0 and is (C=C ₀+ i*180 °/N) locate, C wherein ₀Be initial position, i=0,1 ... N-1;

(d) at each place, position angle, imageing sensor carries out time exposure integration, data is sent to carries out computing and storage in the computing machine then;

(e) carry out step (c)-(d) repeatedly for N time, finish until one-period;

(f) N the data that each pixel is obtained are carried out data processing (utilizing the Fourier analysis method to carry out usually), obtain the value of each coefficient in the formula (1);

(g) utilize the relational expression of each coefficient and sample ellipsometric parameter (ψ and Δ) to obtain on the sample ellipsometric parameter of each microcell (ψ and Δ) on the corresponding region.

In the above process, the sequential chart of the data processing of the data acquisition of the angular velocity of rotation of compensator, imageing sensor and computing machine and analysis as shown in Figure 1 in a sampling unit.As can be seen, when this method was used for the ellipsometry imaging sampling, the needed time was in the sampling period:

t＝N(t _i+1-t _i)≥N(t _start+t _run+t _stop+t _sensor+t _cal) (2)

T wherein _StartStart-up time for the universal stage of compensator, normally be increased to a certain angular velocity omega from angular velocity 0; t _RunThe time of at the uniform velocity moving with speed omega for the universal stage of compensator; t _StoptStand-by time for the universal stage of compensator normally is reduced to 0 from angular velocity omega; t _SensorBe the exposure integral time and the used time of signal output of imageing sensor; t _CalBe calculating and the storage time of picture signal in computing machine.In formula (2), used time of first three items usually with back two time quite or bigger.

By above analysis, adopt the ellipsometry imaging system of the whirl compensator of multi-point sampling method to have following deficiency as can be seen:

(1) the device frequent starting, stop, causing controlling the precision difficulty, bring the instability of system;

(2) sampling time longer, be limited by start and stop performance, the travelling speed of motor strongly.These problems have limited the temporal resolution of further raising system, can't be used for fast-changing sample condition.

As shown in Figure 3, the ellipsometry imaging device of the whirl compensator of a kind of multi-point sampling method that adopts at present comprises incident unit 1, outgoing unit 3, data acquisition process unit 4.Wherein, incident unit 1 specifically comprises incident arm 16 and coaxially is installed in collimated monochromatic light generator 11, first linear polarization 12 and universal stage 13 on the incident arm 16 with the incident cell optic axis successively.Universal stage 13 can rotate around the incident cell optic axis, with the incident cell optic axis phase compensator 14 and angular encoder 15 are installed coaxially successively on the universal stage 13, phase compensator 14 can rotate around the incident cell optic axis with universal stage 13 synchronously with angular encoder 15.Incident arm 16 is used to carry various elements, makes its coaxial arrangement.Collimated monochromatic light generator 11 is used to produce and expand the quasi-monochromatic light output of collimation.First linear polarization 12 is used for detecting light beam is transformed to linearly polarized photon.Universal stage 13 is used to make element fixed thereon around the rotation of incident cell optic axis.Phase compensator 14 is used for producing a phase-delay difference on two mutually perpendicular directions, thereby changes the polarization polarization state of light.Angular encoder 15 is used to write down the position angle of phase compensator 14.

Outgoing unit 3 specifically comprises outgoing arm 36 and coaxially is installed in second linear polarization 31, imaging lens 32 and imageing sensor 33 on the outgoing arm 36 with the outgoing cell optic axis successively.Outgoing arm 36 is used to carry various elements, makes its coaxial arrangement.Second linear polarization 31 is used for the direct reflection polarization state of sample 20 is modulated into linearly polarized photon.Imaging lens 32 is used for sample is carried out imaging.Imageing sensor 33 is used to receive sample through the optics real image that imaging lens became, and is translated into electric signal.

Data acquisition process unit 4 specifically comprises control box 41, data acquisition unit 43 and robot calculator 42.Imageing sensor 33 is electrically connected with data acquisition unit 43, and data acquisition unit 43 is used for the picture signal that imageing sensor 33 collects is converted to the electronic signal that robot calculator 42 can receive.Control box 41 is electrically connected with universal stage 13, is used for driven in rotation platform 13 drive phase compensators 14 and at the uniform velocity rotates; Control box 41 is electrically connected with angular encoder 15, is used to receive the position signalling from angular encoder 15.Data acquisition unit 43 and imageing sensor 33 are electrically connected, and are used for the picture signal that imageing sensor 33 collects is converted to the electronic signal that robot calculator 42 can receive; Robot calculator 42 is used for the motion control and the data processing of total system; Robot calculator 42 is electrically connected with data acquisition unit 43, sends the steering order of data acquisition on the one hand, receives the view data from data acquisition unit 43 on the other hand; Robot calculator 42 is electrically connected with control box, the motion of parts in the control system, and reception is from the state feedback information of device.

As shown in Figure 5, the ellipsometry imaging device of the whirl compensator of the another kind of multi-point sampling method that adopts at present comprises incident unit 1, outgoing unit 3, data acquisition process unit 4.Wherein, incident unit 1 specifically comprises incident arm 16 and coaxially is installed in collimated monochromatic light generator 11, first linear polarization 12 on the incident arm 16 with the incident cell optic axis successively.Incident arm 16 is used to carry various elements, makes its coaxial arrangement.Collimated monochromatic light generator 11 is used to produce and expand the quasi-monochromatic light output of collimation.First linear polarization 12 is used for detecting light beam is transformed to linearly polarized photon.

Outgoing unit 3 specifically comprises outgoing arm 36 and coaxially is installed in universal stage 13 and second linear polarization 31, imaging lens 32 and imageing sensor 33 on the outgoing arm 36 with the outgoing cell optic axis successively.Outgoing arm 36 is used to carry various elements, makes its coaxial arrangement.Universal stage 13 can lay out penetrates the cell optic axis rotation, with the outgoing cell optic axis phase compensator 14 and angular encoder 15 are installed coaxially successively on the universal stage 13, phase compensator 14 can lay out with universal stage 13 with angular encoder 15 and penetrate cell optic axis and rotate synchronously.Second linear polarization 31 is used for the direct reflection polarization state of sample 20 is modulated into linearly polarized photon.Imaging lens 32 is used for sample is carried out imaging.Imageing sensor 33 is used to receive sample through the optics real image that imaging lens became, and is translated into electric signal.

Data acquisition process unit 4 specifically comprises control box 41, data acquisition unit 43 and robot calculator 42.Imageing sensor 33 is electrically connected with data acquisition unit 43, and data acquisition unit 43 is used for the picture signal that imageing sensor 33 collects is converted to the electronic signal that robot calculator 42 can receive.Control box 41 is electrically connected with universal stage 13, is used for driven in rotation platform 13 drive phase compensators 14 and at the uniform velocity rotates; Control box 41 is electrically connected with angular encoder 15, is used to receive the position signalling from angular encoder 15.Data acquisition unit 43 and imageing sensor 33 are electrically connected, and are used for the picture signal that imageing sensor 33 collects is converted to the electronic signal that robot calculator 42 can receive; Robot calculator 42 is used for the motion control and the data processing of total system; Robot calculator 42 is electrically connected with data acquisition unit 43, sends the steering order of data acquisition on the one hand, receives the view data from data acquisition unit 43 on the other hand; Robot calculator 42 is electrically connected with control box, the motion of parts in the control system, and reception is from the state feedback information of device.

Summary of the invention

At the problem that prior art exists, the purpose of this invention is to provide a kind of ellipsometry imaging method and device that can guarantee the employing rotating compensator integration sampling controlling precision and can reduce the sampling time.

For solving the problems of the technologies described above, the objective of the invention is to overcome above-mentioned deficiency, adopt at the uniform velocity whirl compensator and utilize the time integral method and apparatus to sample, realize quick sampling and can guarantee to control precision.

The invention provides a kind of ellipsometry imaging method that adopts rotating compensator integration sampling, described method comprises the steps:

Steps A: system is provided with;

Step B: imageing sensor carries out the time integral exposure;

Step C: data are changed, transmit, handled and store;

Step D: the data that collect are calculated.

Further, described steps A specifically comprises:

A., the sampling unit number N that divides equally in 1 sampling period is set;

B. be provided with and need the sampling number of repetition M in the measurement.

Further, described step B specifically comprises:

C. robot calculator 42 at the uniform velocity rotates by drive control box 41 driving phase compensator spinners 15;

D. at interval (180 °/outgoing position signal pulse N), the pulse signal synchronous triggering imageing sensor 33 after control box 41 is handled carries out the time integral exposure of optical imagery to angular encoder 15 equal angles, forms electronic image then.

Further, described step C specifically comprises:

E. data acquisition unit 43 is given robot calculator 42 digital data transmission from imageing sensor 33, is carried out computing, processing and/or the storage of view data then by robot calculator 42;

F. repeating step d.-e. is until finishing number of samples N * M.

Further, described step D is specially:

The luminous energy value that measures according to each pixel in the image and the relation of ellipsometric parameter (ψ and Δ), the ellipsometric parameter value of corresponding region on the calculation sample.

The present invention also provides a kind of ellipsometry imaging device that adopts rotating compensator integration sampling, and described device comprises:

The incident unit is used to produce collimation, monochrome, the controlled polarized lightwave of polarization state, and oblique incidence is to sample surfaces;

The outgoing unit, the optical axis of the optical axis of described outgoing unit and described incident unit is used to receive the reflected light from sample, and its polarization state is modulated, and obtains the ellipse inclined to one side image of sample;

The data acquisition process unit is used to gather the data of described outgoing unit generation and handle;

Described data acquisition process unit triggers the ellipse inclined to one side image that the outgoing unit obtains sample by the mode of hard triggering.

On the one hand, described incident unit specifically comprises:

The incident arm is used to carry various elements, makes its coaxial arrangement;

The collimated monochromatic light generator coaxially is installed on the described incident arm with the incident cell optic axis, is used to produce and expand the quasi-monochromatic light output of collimation;

First linear polarization coaxially is installed on the described incident arm with the incident cell optic axis, is positioned at described collimated monochromatic light generator back, is used for detecting light beam is transformed to linearly polarized photon;

Universal stage coaxially is installed on the described incident arm with the incident cell optic axis, is positioned on first linear polarization light path afterwards, can be used to make element fixed thereon around the rotation of incident cell optic axis around the rotation of incident cell optic axis;

Phase compensator coaxially is installed on the universal stage with the incident cell optic axis, can be used for producing a phase-delay difference on two mutually perpendicular directions, thereby change the polarization polarization state of light with universal stage jointly around the rotation of incident cell optic axis;

Angular encoder coaxially is installed on the described universal stage with the incident cell optic axis, can be with universal stage jointly around the rotation of incident cell optic axis, the position angle that is used to write down phase compensator;

Described outgoing unit specifically comprises:

The outgoing arm is used to carry various elements, makes its coaxial arrangement;

Second linear polarization coaxially is installed on the outgoing arm with the outgoing cell optic axis, is used for the direct reflection polarization state of sample is modulated into linearly polarized photon;

Imaging lens, coaxially be installed on the outgoing arm with the outgoing cell optic axis, this imaging lens is according to the requirement of imaging magnification, coaxial being placed on the emergent light axis after second linear polarization, or be placed between the sample and second linear polarization, be used for sample is carried out imaging;

Imageing sensor is used to receive sample through the optics real image that imaging lens became, and is translated into electric signal;

Described data acquisition process unit specifically comprises:

Control box is electrically connected with universal stage, is used for driven in rotation platform drive phase compensator and at the uniform velocity rotates; Control box is electrically connected with angular encoder, is used to receive the position signalling from angular encoder; Control box is electrically connected with imageing sensor, is used for the angle signal of angular encoder changed into can triggering imageing sensor and beginning the pulse signal of integration that exposes, thereby imageing sensor is triggered control firmly;

Data acquisition unit and imageing sensor are electrically connected, and are used for the picture signal that imageing sensor collects is converted to the electronic signal that robot calculator can receive;

Robot calculator is used for the motion control and the data processing of total system; Robot calculator is electrically connected with data acquisition unit, sends the steering order of data acquisition on the one hand, receives the view data from data acquisition unit on the other hand; Robot calculator is electrically connected with control box, the motion of parts in the control system, and reception is from the state feedback information of device.

On the other hand, described incident unit specifically comprises:

The incident arm is used to carry various elements, makes its coaxial arrangement;

The collimated monochromatic light generator coaxially is installed on the described incident arm with the incident cell optic axis, is used to produce and expand the quasi-monochromatic light output of collimation;

First linear polarization coaxially is installed on the described incident arm with the incident cell optic axis, is positioned at described collimated monochromatic light generator back, is used for detecting light beam is transformed to linearly polarized photon;

Described outgoing unit specifically comprises:

The outgoing arm is used to carry various elements, makes its coaxial arrangement;

Universal stage coaxially is installed on the described outgoing arm with the outgoing cell optic axis, can lay out to penetrate the cell optic axis rotation, is used to make element fixed thereon around the rotation of outgoing cell optic axis;

Phase compensator coaxially is installed on the described universal stage with the outgoing cell optic axis, can lay out jointly with universal stage and penetrate the cell optic axis rotation, is used for producing a phase-delay difference on two mutually perpendicular directions, thereby changes the polarization polarization state of light;

Angular encoder coaxially is installed on the described universal stage with the outgoing cell optic axis, is positioned at after the phase compensator, can lay out jointly with universal stage and penetrate cell optic axis rotation, the position angle that is used to write down phase compensator;

Second linear polarization coaxially is installed on the outgoing arm with the outgoing cell optic axis, is used for the direct reflection polarization state of sample is modulated into linearly polarized photon;

Imaging lens, coaxially be installed on the outgoing arm with the outgoing cell optic axis, this imaging lens is according to the requirement of imaging magnification, coaxial being placed on the emergent light axis after second linear polarization, or be placed between the sample and second linear polarization, be used for sample is carried out imaging;

Imageing sensor is used to receive sample through the optics real image that imaging lens became, and is translated into electric signal;

Described data acquisition process unit specifically comprises:

Control box is electrically connected with universal stage, is used for driven in rotation platform drive phase compensator and at the uniform velocity rotates; Control box is electrically connected with angular encoder, is used to receive the position signalling from angular encoder; Control box is electrically connected with imageing sensor, is used for the angle signal of angular encoder changed into can triggering imageing sensor and beginning the pulse signal of integration that exposes, thereby imageing sensor is triggered control firmly;

Data acquisition unit and imageing sensor are electrically connected, and are used for the picture signal that imageing sensor collects is converted to the electronic signal that robot calculator can receive;

Robot calculator is used for the motion control and the data processing of total system; Robot calculator is electrically connected with data acquisition unit, sends the steering order of data acquisition on the one hand, receives the view data from data acquisition unit on the other hand; Robot calculator is electrically connected with control box, the motion of parts in the control system, and reception is from the state feedback information of device.

Further, described control box comprises the receiving trap of motion control card, motor driver, position feedback device at least; Wherein motion control card is electrically connected with the receiving trap of robot calculator, motor driver and position feedback device respectively, motion control card carries out motion control issuing motor driver from the instruction of robot calculator after by electronic switch, and passing to computing machine from the position command of position feedback device; Motor driver is electrically connected with motor, and drive motor produces motion; The detectable signal of the receiving trap receiving position ultramagnifier of position feedback device, and signal passed to motion control card.

Further, described phase compensator is the optics anisotropic device that can produce certain phase-delay difference on two mutually perpendicular directions.

Further, described phase compensator is mica waveplate, quartz wave-plate, liquid crystal wave plate.

Further, described first linear polarization or second linear polarization are for being transformed into any light wave the polarizer of linearly polarized light.

Further, described first linear polarization or second linear polarization are dichroism linear polarization or Glan-Taylor polarizing prism or Glan-Thompson polarizing prism.

Further, described imageing sensor is for utilizing the time integral mode inciding the array photoelectricity converted image sensor that light distribution signal on its image sensing surface changes into electric signal.

Further, described imageing sensor is charge-coupled image sensor, cmos image sensor.

Further, described collimated monochromatic light generator is formed by continuous spectrum light source and light-splitting device and collimation lens combination, or is formed by monochromatic light emitters part and collimation lens combination.

Further, described light-splitting device is spectrometer or optical filter, and described monochromatic light emitters part is laser instrument or light emitting diode.

Further, described angular encoder is the unit that can be divided into circumference several equal angles spacings, and the scrambler that position signalling is exported by coded system.

Further, described angular encoder is photoelectric encoder, magnetic coder.

The invention has the advantages that: utilize the sample temporal resolution of the system that increased substantially of time integral method, can guarantee to control precision and can reduce the sampling time; Adopting at the uniform velocity, the rotatable phase compensator has reached stable purpose.Provide a kind of effective method for measuring large-area nano thin-film sample fast.

Description of drawings

Below in conjunction with the drawings and specific embodiments the present invention is described in further detail:

Fig. 1 is the sequential chart that prior art adopts a sampling unit of whirl compensator multi-point sampling ellipsometry imaging method;

Fig. 2 is the sequential chart of a sampling unit of the present invention's ellipsometry imaging method of adopting rotating compensator integration sampling;

Fig. 3 is a kind of structural representation that prior art adopts whirl compensator multi-point sampling ellipsometry imaging device;

Fig. 4 is a kind of structural representation that the present invention adopts the ellipsometry imaging device of rotating compensator integration sampling;

Fig. 5 is the another kind of structural representation that prior art adopts whirl compensator multi-point sampling ellipsometry imaging device;

Fig. 6 is the another kind of structural representation that the present invention adopts the ellipsometry imaging device of rotating compensator integration sampling.

Embodiment

Embodiment 1:

The embodiment of the invention 1 provides a kind of ellipsometry imaging method that adopts rotating compensator integration sampling, and described method comprises the steps:

Steps A: system is provided with;

Specifically comprise:

A., the sampling unit number N that divides equally in 1 sampling period (180 °) is set;

B. be provided with and need the sampling number of repetition M in the measurement.

Step B: imageing sensor carries out the time integral exposure;

Specifically comprise:

C. robot calculator 42 at the uniform velocity rotates by drive control box 41 driving phase compensator spinners 15;

D. at interval (180 °/outgoing position signal pulse N), the pulse signal synchronous triggering imageing sensor 33 after control box 41 is handled carries out the time integral exposure of optical imagery to angular encoder 15 equal angles, forms electronic image then.

Step C: data are changed, transmit, handled and store;

Specifically comprise:

E. data acquisition unit 43 is given robot calculator 42 digital data transmission from imageing sensor 33, is carried out computing, processing and/or the storage of view data then by robot calculator 42;

F. repeating step d-e is until finishing number of samples N * M.

Step D: the data that collect are calculated.

Be specially:

The luminous energy value that measures according to each pixel in the image and the relation of ellipsometric parameter (ψ and Δ), the value of the ellipsometric parameter of corresponding region on the calculation sample (ψ and Δ).

In the said process, imageing sensor 33 is to carry out work by the output signal of angular encoder 15 as synchronous triggering signal.Fig. 2 has provided the angular velocity of rotation ω of an interior compensator of sampling unit, data acquisition and the data processing of computing machine and the sequential chart of analysis of imageing sensor.As can be seen, when this method was used for the ellipsometry imaging system, the needed time comprised in the sampling period:

t＝N(t _i+1-t _i)≥N(t _sensor+t _cal) (3)

t _i+1-t _i≥t _sensor+t _cal

In said process, C=ω _CIn t substitution (1) formula, the signal form that obtains arbitrary pixel on the imageing sensor is

I(ω _Ct)＝I ₀(1+α ₂′cos2ω _Ct+β ₂′sin2ω _Ct+α ₄′cos4ω _Ct+β ₄′sin4ω _Ct) (4)

ω wherein _CBe the angular velocity of phase compensator 13.

Because the time of a phase compensator rotation sampling period (180 °) is

So the time of each equally spaced sampling unit is

$T=\frac{\mathrm{\π}}{{\mathrm{N\ω}}_C}$

If the exposure sampling time of imageing sensor is t _e=XT (wherein, 0＜X≤1, the dutycycle of expression exposure sampling time and sampling unit), so, exposure is integral time

$t_e=X\frac{\mathrm{\π}}{{\mathrm{N\ω}}_C}$

So, imageing sensor j (j=0,1,2 ... N-1) the photon integrated signal that obtains in the individual sampling unit is

$S_j=I_0{\∫}_{\frac{\mathrm{j\π}}{{\mathrm{N\ω}}_C}}^{\frac{\mathrm{j\π}}{{\mathrm{N\ω}}_C}+\mathrm{te}}\{1+\underset{n=1}{\overset{2}{\mathrm{\Σ}}}{{\mathrm{\α}}^{\′}}_{2n}\cos 2n{\mathrm{\ω}}_{C}t+{{\mathrm{\β}}^{\′}}_{2n}\sin 2n{\mathrm{\ω}}_{C}t\}\mathrm{dt}---\left(5\right)$

Can derive and obtain

$\frac{S_j}{{I_0}^{\′}}-t_e=\underset{n=1}{\overset{2}{\mathrm{\Σ}}}\frac{\sin \left({\mathrm{n\ω}}_C{t}_e\right)}{{\mathrm{n\ω}}_C}\left\{{{\mathrm{\α}}^{\′}}_{2n}\cos \right[{\mathrm{n\ω}}_C(\frac{2\mathrm{j\π}}{{\mathrm{N\ω}}_C}+t_e)]+{{\mathrm{\β}}^{\′}}_{2n}\sin [{\mathrm{n\ω}}_C(\frac{2\mathrm{j\π}}{{\mathrm{N\ω}}_C}+t_e)\left]\right\}---\left(6\right)$

From following formula, 5 unknown number I are arranged in the formula ₀, α ₂', β ₂', α ₄', β ₄', just can from N the system of equations that obtains, solve unknown number so need to carry out 5 samplings (being N 〉=5) at least.

Such as, can obtain following relational expression during N=8:

$I_0=({\mathrm{<figure-callout\; id="0"\; label="S"\; filenames="S2008101022712E00011.png,S2008101022712E00012.png"\; state="\{\{state\}\}">S</figure-callout>}}_0+{\mathrm{<figure-callout\; id="1"\; label="S"\; filenames="S2008101022712E00031.png"\; state="\{\{state\}\}">S</figure-callout>}}_1+S_2+{\mathrm{<figure-callout\; id="3"\; label="S"\; filenames="S2008101022712E00011.png,S2008101022712E00012.png"\; state="\{\{state\}\}">S</figure-callout>}}_3+{\mathrm{<figure-callout\; id="4"\; label="S"\; filenames="S2008101022712E00021.png"\; state="\{\{state\}\}">S</figure-callout>}}_4+S_5+S_6+S_7)\frac{{\mathrm{\&omega;}}_C}{\mathrm{X\&pi;}}$

${{\mathrm{\&alpha;}}_2}^{\&prime;}=\left\{({\mathrm{<figure-callout\; id="0"\; label="S"\; filenames="S2008101022712E00011.png,S2008101022712E00012.png"\; state="\{\{state\}\}">S</figure-callout>}}_0+S_1-S_4-S_5)\right[\frac{\cot \frac{\mathrm{X\&pi;}}{8}}{2}-\frac{1}{2(1+\sqrt{2})}]-(S_2+S_3-S_6-S_7)[\frac{\cot \frac{\mathrm{X\&pi;}}{8}}{2(1+\sqrt{2})}+\frac{1}{2}\left]\right\}\frac{{\mathrm{\&omega;}}_C}{2{\mathrm{<figure-callout\; id="0"\; label="I"\; filenames="S2008101022712E00011.png,S2008101022712E00012.png"\; state="\{\{state\}\}">I</figure-callout>}}_0}$

${{\mathrm{\&beta;}}_2}^{\&prime;}=\left\{\right[\frac{\cot \frac{\mathrm{X\&pi;}}{8}}{2(1+\sqrt{2})}+\frac{1}{2}]({\mathrm{<figure-callout\; id="0"\; label="S"\; filenames="S2008101022712E00011.png,S2008101022712E00012.png"\; state="\{\{state\}\}">S</figure-callout>}}_0+S_1-S_4-S_5)+[\frac{\cot \frac{\mathrm{X\&pi;}}{8}}{2}-\frac{1}{2(1+\sqrt{2})}\left](S_2+S_3-S_6-S_7)\right\}\frac{{\mathrm{\&omega;}}_C}{2I_0}---\left(7\right)$

${{\mathrm{\&alpha;}}_4}^{\&prime;}=\{\cot \frac{\mathrm{X\&pi;}}{4}(S_0-S_2+S_4-S_6)-(S_1-{\mathrm{<figure-callout\; id="3"\; label="S"\; filenames="S2008101022712E00011.png,S2008101022712E00012.png"\; state="\{\{state\}\}">S</figure-callout>}}_3+S_5-S_7)\}\frac{{\mathrm{\&omega;}}_C}{2{\mathrm{<figure-callout\; id="0"\; label="I"\; filenames="S2008101022712E00011.png,S2008101022712E00012.png"\; state="\{\{state\}\}">I</figure-callout>}}_0}$

${{\mathrm{\&beta;}}_4}^{\&prime;}=\{(S_0-S_2+S_4-S_6)+(S_1-{\mathrm{<figure-callout\; id="3"\; label="S"\; filenames="S2008101022712E00011.png,S2008101022712E00012.png"\; state="\{\{state\}\}">S</figure-callout>}}_3+S_5-S_7)*\cot \frac{\mathrm{X\&pi;}}{4}\}\frac{{\mathrm{\&omega;}}_C}{2{\mathrm{<figure-callout\; id="0"\; label="I"\; filenames="S2008101022712E00011.png,S2008101022712E00012.png"\; state="\{\{state\}\}">I</figure-callout>}}_0}$

Utilize the parameter of each expression formula and system's setting (comprising the first linear polarization position angle, the second linear polarization position angle, phase compensator phase differential etc.) and sample then, just can obtain the ellipsometric parameter (ψ, Δ) of sample.Such as, ellipsometry imaging system for the polarizer-compensator-sample-analyzer structure, as analyzer position angle A=± 45 °, just can utilize following formula to obtain ellipse drift angle (the list of references 10:Kleim R of sample, Kuntzler L, Elghemmaz A, Systematic errors in rotating-compensator ellipsometery, Journal of theoptical society of America A A-Optics image science and vision, 1994,11 (9): 2550-2559):

$\tan 2\mathrm{\&Psi;}=\frac{\sqrt{({{\mathrm{\&beta;}}_2}^{\&prime;2}+{{\mathrm{\&alpha;}}_2}^{\&prime;2}){\tan }^2\frac{{\mathrm{\&delta;}}_C}{2}+4{({{\mathrm{\&beta;}}_4}^{\&prime;}\cos 2P-{{\mathrm{\&alpha;}}_4}^{\&prime;}\sin 2P)}^2}}{-2({{\mathrm{\&alpha;}}_4}^{\&prime;}\cos 2P+{{\mathrm{\&beta;}}_4}^{\&prime;}\sin 2P)}---\left(8\right)$

$\tan \mathrm{\&Delta;}=\frac{1}{2}\tan \left(\frac{{\mathrm{\&delta;}}_C}{2}\right)\frac{{{\mathrm{\&alpha;}}_2}^{\&prime;}\sin 2P-{{\mathrm{\&beta;}}_2}^{\&prime;}\cos 2P}{{{\mathrm{\&alpha;}}_4}^{\&prime;}\sin 2P-{{\mathrm{\&beta;}}_4}^{\&prime;}\cos 2P}$

Wherein, P is polarizer position angle, δ _CBe the compensator phase-delay difference.

By above analysis, adopt the integration method sampling to have following advantage: (1) is adopted device at the uniform velocity to rotate and has been reached and stablize, and has improved the stability of system; (2) adopt the time integral method, synchronous with the integral time of imageing sensor, improved sample rate greatly.

Embodiment 2:

With reference to the accompanying drawings 4, the invention provides a kind of ellipsometry imaging device that adopts rotating compensator integration sampling, this device comprises: incident unit 1, outgoing unit 3 and data acquisition process unit 4.

Wherein, incident unit 1 is used to produce collimation, monochrome, the controlled polarized lightwave of polarization state, and oblique incidence is to sample surfaces;

Incident unit 1 specifically comprises:

Incident arm 16 is used to carry various elements, makes its coaxial arrangement;

Collimated monochromatic light generator 11, coaxially be installed on the leading section of incident arm 16 with the incident cell optic axis, form by continuous spectrum light source (as xenon lamp, Halogen lamp LED etc.) and light-splitting device (as spectrometer or optical filter etc.) and collimation lens combination, form as broad spectrum light source (as xenon lamp, Halogen lamp LED etc.)-condenser-monochromator-collimating mirror; Or form by the combination of monochromatic light emitters part (as laser instrument or light emitting diode) and collimation lens, as laser instrument-beam expanding lens, light emitting diode-optical filter-collimation lens; The optical axis coincidence of the optical axis of collimation lens and incident arm.Be used to produce and expand the quasi-monochromatic light output of collimation;

First linear polarization 12 is for being transformed into any light wave the polarizer of linearly polarized light, for example dichroism linear polarization or Glan-Taylor polarizing prism or Glan-Thompson polarizing prism.First linear polarization 12 coaxially is installed on the incident arm 16 with the incident cell optic axis, is positioned at collimated monochromatic light generator 11 back, is used for detecting light beam is transformed to linearly polarized photon;

Universal stage 13 coaxially is installed on the angular velocity incident arm 16 with the incident cell optic axis, is positioned on first linear polarization 12 light path afterwards, can be used to make element fixed thereon around the rotation of incident cell optic axis around 360 ° of rotations of incident cell optic axis;

Phase compensator 14 is for can produce the optics anisotropic device of certain phase-delay difference on two mutually perpendicular directions, as mica wave plate, quartz wave-plate, liquid crystal wave plate.Phase compensator 14 coaxially is installed on the universal stage 13 with the incident cell optic axis, can be used for producing a phase-delay difference on two mutually perpendicular directions, thereby change the polarization polarization state of light with universal stage 13 jointly around the rotation of incident cell optic axis;

Angular encoder 15, it is the unit that can be divided into circumference several equal angles spacings, and the scrambler that position signalling is exported by coded system, as photoelectric encoder, magnetic coder, coaxially be installed on the angular velocity universal stage 13 with the incident cell optic axis, be positioned at after the phase compensator 14, can rotate synchronously around the incident cell optic axis, be used to write down the position angle of phase compensator 14 with universal stage 13.

Outgoing unit 3 is used to receive the reflected light from sample 20, and its polarization state is modulated, and obtains the ellipse inclined to one side image of sample 20;

Outgoing unit 3 specifically comprises:

Outgoing arm 36 is used to carry various elements, makes its coaxial arrangement;

Second linear polarization 31 is for being transformed into any light wave the polarizer of linearly polarized light, as dichroism linear polarization or Glan-Taylor polarizing prism or Glan-Thompson polarizing prism.Second linear polarization 31 coaxially is installed on the outgoing arm 36 with the outgoing cell optic axis, is used for the direct reflection polarization state of sample 20 is modulated into linearly polarized photon;

Imaging lens 32, coaxially be installed on the outgoing arm 36 with the outgoing cell optic axis, this imaging lens 32 is according to the requirement of imaging magnification, coaxial being placed on the emergent light axis after second linear polarization 31, or be placed between the sample 20 and second linear polarization 31, be used for sample is carried out imaging;

Imageing sensor 33 is used to receive the optics real image that sample is become through imaging lens 32, and is translated into electric signal; Imageing sensor 33 is for utilizing the time integral mode inciding the array photoelectricity converted image sensor that light distribution signal on its image sensing surface changes into electric signal, as charge-coupled device (CCD), complementary metal oxide semiconductor (CMOS) (CMOS) imageing sensor.

Data acquisition process unit 4 is used to gather the data of outgoing unit 3 generations and handle; Data acquisition process unit 4 triggers the ellipse inclined to one side image that outgoing unit 3 obtains sample 20 by the mode of hard triggering.

Data acquisition process unit 4 specifically comprises:

Control box 41 is electrically connected with universal stage 13, is used for driven in rotation platform 13 drive phase compensators 14 and at the uniform velocity rotates; Control box 41 is electrically connected with angular encoder 15, is used to receive the position signalling from angular encoder 15; Control box 41 is electrically connected with imageing sensor 33, is used for the angle signal of angular encoder 15 changed into can triggering imageing sensor 33 and beginning the pulse signal of integration that exposes, thereby imageing sensor 33 is triggered control firmly;

Control box 41 comprises the receiving trap of motion control card, motor driver, position feedback device at least; Wherein motion control card is electrically connected with the receiving trap of robot calculator 42, motor driver and position feedback device respectively, motion control card carries out motion control issuing motor driver from the instruction of robot calculator 42 after by electronic switch, and passing to robot calculator 42 from the position command of position feedback device; Motor driver is electrically connected with motor, and drive motor produces motion; The detectable signal of the receiving trap receiving position ultramagnifier of position feedback device, and signal passed to motion control card.

Data acquisition unit 43 and imageing sensor 33 are electrically connected, and are used for the picture signal that imageing sensor 33 collects is converted to the electronic signal that robot calculator 42 can receive;

Robot calculator 42 is used for the motion control and the data processing of total system; Robot calculator 42 is electrically connected with data acquisition unit 43, sends the steering order of data acquisition on the one hand, receives the view data from data acquisition unit 43 on the other hand; Robot calculator 42 is electrically connected with control box, the motion of parts in the control system, and reception is from the state feedback information of device.

Collimated monochromatic light generator 11, first linear polarization 12 and the phase compensator 14 that is installed in the universal stage 13 successively coaxially are installed on the incident arm 16 successively, and its optical axis is an incident light axis.Wherein universal stage 13 can carry out 360 ° of rotations.Sample 20 is for having the nano film material (as unmarked multielement protein matter chip) of complicated transversary, samples vertical is in the plane of incidence, and central shaft is passed through on its surface, be used to receive, and the polarization state of this light wave is modulated from the expansion collimation that plays part generation partially, the oblique illumination of accurate monochromatic polarized lightwave; Universal stage 13 is the accurate transmission mechanism by the worm gear-endless screw structure of driven by motor, and the motor on it is electrically connected with motor driver in the drive control box 41.Robot calculator 42 sends instruction to the motor control card in the drive control box 41, and driven rotary platform 13 at the uniform velocity rotated after motor control card passed to motor driver with this signal then, thereby changes the position angle of phase compensator 14.The azimuth signal of angular encoder 15 output phase compensators 14, and by being transformed into the synchronous triggering signal of the integration that can control chart image-position sensor 33 begins to expose behind the control box 41.The electronic image signal that imageing sensor 33 produces is transformed into the signal that robot calculator 42 can receive and handle through data acquisition unit 43, and this picture signal is handled and stored in robot calculator 42.

In the light path emission parts, linear polarization 31, image-forming objective lens 32 and imageing sensor 33 coaxial being installed in successively on the outgoing arm 3, its optical axis overlaps with emergent light axis.The installation of imageing sensor 33 guarantees that its image sensing surface overlaps through the real image that image-forming objective lens 32 is become with sample 20.

The optical axis intersection of the optical axis of incident arm (1) and outgoing arm (36) is on sample surfaces, the plane of incidence of the two formation is perpendicular to the surface of sample, and the incident angle that the optical axis of incident arm (1) and sample normal form equals the optical axis of outgoing arm (36) and the emission angle that the sample normal forms.

Described drive control box 41 comprises the receiving trap of motor control card, motor driver, position feedback device; Wherein motor control card is electrically connected with the receiving trap of computing machine 42, motor driver and position feedback device respectively, motor control card carries out motion control issuing motor driver from the instruction of computing machine 42 after by electronic switch, and passing to computing machine from the position command of position feedback device; Motor driver is electrically connected with motor, and drive motor produces motion; The detectable signal of the receiving trap receiving position ultramagnifier of position feedback device, and signal passed to motor control card.

The electric signal of the image that the described imageing sensor of present embodiment 33 forms enters data acquisition unit 43 to be converted into computing machine with the electronic signal of image after handling and can to handle picture signal, enter robot calculator 42 afterwards, utilize robot calculator that these images are analyzed, can obtain the ellipsometric parameter distribution situation of sample surfaces, and obtain information such as sample thickness, refractive index, roughness in view of the above.

Robot calculator 42 is electrically connected with motor control card in the control box 41, send the motor of instruction driven in rotation platform 13 by the motor driver in drive control box 41, thereby the position angle of phase delay device 14, and its position feedback is returned drive control box 41, by drive control box 41 and robot calculator 42 communications, motion state is reported to robot calculator, to carry out next step motion control.

For sample of quantitative measurment, such as, sample the protein-chip of multiunit nanometer scale thickness of preparing on the silicon base, for the ellipsometric parameter (ψ and Δ) that obtains above-mentioned sample.Adopt following step:

(a) the sampling unit number N that divides equally in 1 sampling period (180 °) is set;

(b) be provided with and need the sampling number of repetition M in the measurement;

(c) robot calculator 42 at the uniform velocity rotates by control box 41 driven in rotation devices 13 drive phase compensators 14, and angular velocity is ω _C

(d) angular encoder 15 equal angles at interval (180 °/export a position signalling pulse to enter control box 41 N), control box sends a synchronous triggering signal to imageing sensor 33, makes it begin to carry out the time integral exposure of optical imagery;

(e) data acquisition unit 43 is transferred to robot calculator 42 to the signal from imageing sensor 33 after conversion, carries out computing, processing and/or the storage of view data then;

(f) repeating step (d)-(e) reaches N * M until number of samples;

(g) the luminous energy value that measures according to each pixel in the image calculates the ellipsometric parameter value (ψ and Δ) of corresponding region on the sample.

Because phase compensator 14 is rotated always, institute's image taking sensor 33 need obtain real-time trigger pip, by control box 41 is electrically connected with imageing sensor 33,41 pairs of imageing sensors 33 of control box are triggered firmly, (existing ellipsometry imaging device is after equiphase compensator 14 forwards a certain position to and stops and not adopting 42 pairs of imageing sensors of robot calculator 33 in the existing ellipsometry imaging device to carry out the mode of soft triggering, trigger imageing sensor 33 again, make it begin to carry out the time integral exposure of optical imagery, adopt soft triggering also can not produce the problem of trigger delay under this mode), can reduce the generation of trigger delay, guarantee to control precision.

Embodiment 3:

6 the invention provides the another kind of ellipsometry imaging device that adopts rotating compensator integration sampling with reference to the accompanying drawings, this device comprises: incident unit 1, outgoing unit 3 and data acquisition process unit 4.

And Fig. 4 position that is not both phase place universal stage 13, phase compensator 14 and angular encoder structurally is not to be placed between linear polarization 12 and the sample 20, but be placed between sample 20 and the linear polarization 31, promptly not to be placed on the incident arm 16, but be placed on the outgoing arm 36.

Incident unit 1 specifically comprises:

Incident arm 16 is used to carry various elements, makes its coaxial arrangement;

Collimated monochromatic light generator 11, coaxially be installed on the leading section of incident arm 16 with the incident cell optic axis, form by continuous spectrum light source (as xenon lamp, Halogen lamp LED etc.) and light-splitting device (as spectrometer or optical filter etc.) and collimation lens combination, form as broad spectrum light source (as xenon lamp, Halogen lamp LED etc.)-condenser-monochromator-collimating mirror; Or form by the combination of monochromatic light emitters part (as laser instrument or light emitting diode) and collimation lens, as laser instrument-beam expanding lens, light emitting diode-optical filter-collimation lens; The optical axis coincidence of the optical axis of collimation lens and incident arm.Be used to produce and expand the quasi-monochromatic light output of collimation;

First linear polarization 12 is for being transformed into any light wave the polarizer of linearly polarized light, for example dichroism linear polarization or Glan-Taylor polarizing prism or Glan-Thompson polarizing prism.First linear polarization 12 coaxially is installed on the incident arm 16 with the incident cell optic axis, is positioned at collimated monochromatic light generator 11 back, is used for detecting light beam is transformed to linearly polarized photon;

Outgoing unit 3 specifically comprises:

Outgoing arm 36 is used to carry various elements, makes its coaxial arrangement;

Universal stage 13 coaxially is installed on the outgoing arm 36 with the outgoing cell optic axis, can lay out to penetrate the cell optic axis rotation, is used to make element fixed thereon around the rotation of outgoing cell optic axis;

Phase compensator 14 is for can produce the optics anisotropic device of certain phase-delay difference on two mutually perpendicular directions, as mica wave plate, quartz wave-plate, liquid crystal wave plate.Coaxially be installed on the universal stage 13 with the outgoing cell optic axis, can lay out jointly with universal stage 13 and penetrate the cell optic axis rotation, be used on two mutually perpendicular directions, producing a phase-delay difference, thereby change the polarization polarization state of light;

Angular encoder 15 is the unit that can be divided into circumference several equal angles spacings, and the scrambler that position signalling is exported by coded system, as photoelectric encoder, magnetic coder.Angular encoder 15 coaxially is installed on the universal stage 13 with the outgoing cell optic axis, is positioned at after the phase compensator 14, can lay out jointly with universal stage 13 and penetrate cell optic axis rotation, the position angle that is used to write down phase compensator 14;

Second linear polarization 31 is for being transformed into any light wave the polarizer of linearly polarized light, as dichroism linear polarization or Glan-Taylor polarizing prism or Glan-Thompson polarizing prism.Second linear polarization 31 coaxially is installed on the outgoing arm 36 with the outgoing cell optic axis, is used for the direct reflection polarization state of sample 20 is modulated into linearly polarized photon;

Imaging lens 32, coaxially be installed on the outgoing arm 36 with the outgoing cell optic axis, this imaging lens 32 is according to the requirement of imaging magnification, coaxial being placed on the emergent light axis after second linear polarization 31, or be placed between the sample 20 and second linear polarization 31, be used for sample is carried out imaging;

Imageing sensor 33 is used to receive sample through the optics real image that imaging lens became, and is translated into electric signal; Imageing sensor 33 is for utilizing the time integral mode inciding the array photoelectricity converted image sensor that light distribution signal on its image sensing surface changes into electric signal, as charge-coupled device (CCD), complementary metal oxide semiconductor (CMOS) (CMOS) imageing sensor.

Data acquisition process unit 4 specifically comprises:

Control box 41 is electrically connected with universal stage 13, is used for driven in rotation platform 13 drive phase compensators 14 and at the uniform velocity rotates; Control box 41 is electrically connected with angular encoder 15, is used to receive the position signalling from angular encoder 15; Control box 41 is electrically connected with imageing sensor 33, is used for the angle signal of angular encoder 15 changed into can triggering imageing sensor 33 and beginning the pulse signal of integration that exposes, thereby imageing sensor 33 is triggered control firmly;

Control box 41 comprises the receiving trap of motion control card, motor driver, position feedback device at least; Wherein motion control card is electrically connected with the receiving trap of robot calculator 42, motor driver and position feedback device respectively, motion control card carries out motion control issuing motor driver from the instruction of robot calculator 42 after by electronic switch, and passing to robot calculator 42 from the position command of position feedback device; Motor driver is electrically connected with motor, and drive motor produces motion; The detectable signal of the receiving trap receiving position ultramagnifier of position feedback device, and signal passed to motion control card.

Data acquisition unit 43 and imageing sensor 33 are electrically connected, and are used for the picture signal that imageing sensor 33 collects is converted to the electronic signal that robot calculator 42 can receive;

Robot calculator 42 is used for the motion control and the data processing of total system; Robot calculator 42 is electrically connected with data acquisition unit 43, sends the steering order of data acquisition on the one hand, receives the view data from data acquisition unit 43 on the other hand; Robot calculator 42 is electrically connected with control box, the motion of parts in the control system, and reception is from the state feedback information of device.

Collimated monochromatic light generator 11, first linear polarization 12 successively coaxially are installed on the incident arm 16 successively, and its optical axis is an incident light axis.The phase compensator 14, angular encoder 15, second linear polarization 31, imaging lens 32, the imageing sensor 33 that are installed in the universal stage 13 successively coaxially are installed on the outgoing arm 36 successively, and its optical axis overlaps with emergent light axis.The installation of imageing sensor 33 guarantees that its image sensing surface overlaps through the real image that image-forming objective lens 32 is become with sample 20.Wherein universal stage 13 can carry out 360 ° of rotations.Sample 20 is for having the nano film material (as unmarked multielement protein matter chip) of complicated transversary, samples vertical is in the plane of incidence, and central shaft is passed through on its surface, be used to receive, and the polarization state of this light wave is modulated from the expansion collimation that plays part generation partially, the oblique illumination of accurate monochromatic polarized lightwave; Universal stage 13 is the accurate transmission mechanism by the worm gear-endless screw structure of driven by motor, and the motor on it is electrically connected with motor driver in the drive control box 41.Robot calculator 42 sends instruction to the motor control card in the drive control box 41, and driven rotary platform 13 at the uniform velocity rotated after motor control card passed to motor driver with this signal then, thereby changes the position angle of phase compensator 14.The azimuth signal of angular encoder 15 output phase compensators 14, and by being transformed into the synchronous triggering signal of the integration that can control chart image-position sensor 33 begins to expose behind the control box 41.The electronic image signal that imageing sensor 33 produces is transformed into the signal that robot calculator 42 can receive and handle through data acquisition unit 43, and this picture signal is handled and stored in robot calculator 42.

The optical axis intersection of the optical axis of incident arm (1) and outgoing arm (36) is on sample surfaces, the plane of incidence of the two formation is perpendicular to the surface of sample, and the incident angle that the optical axis of incident arm (1) and sample normal form equals the optical axis of outgoing arm (36) and the emission angle that the sample normal forms.

Described drive control box 41 comprises the receiving trap of motor control card, motor driver, position feedback device; Wherein motor control card is electrically connected with the receiving trap of computing machine 42, motor driver and position feedback device respectively, motor control card carries out motion control issuing motor driver from the instruction of computing machine 42 after by electronic switch, and passing to computing machine from the position command of position feedback device; Motor driver is electrically connected with motor, and drive motor produces motion; The detectable signal of the receiving trap receiving position ultramagnifier of position feedback device, and signal passed to motor control card.

The electric signal of the image that the described imageing sensor of present embodiment 33 forms enters data acquisition unit 43 to be converted into computing machine with the electronic signal of image after handling and can to handle picture signal, enter robot calculator 42 afterwards, utilize robot calculator that these images are analyzed, can obtain the ellipsometric parameter distribution situation of sample surfaces, and obtain information such as sample thickness, refractive index, roughness in view of the above.

Robot calculator 42 is electrically connected with motor control card in the control box 41, send the motor of instruction driven in rotation platform 13 by the motor driver in drive control box 41, thereby the position angle of phase delay device 14, and its position feedback is returned drive control box 41, by drive control box 41 and robot calculator 42 communications, motion state is reported to robot calculator, to carry out next step motion control.

For sample of quantitative measurment, such as, sample the protein-chip of multiunit nanometer scale thickness of preparing on the silicon base, for the ellipsometric parameter (ψ and Δ) that obtains above-mentioned sample.Adopt following step:

(a) the sampling unit number N that divides equally in 1 sampling period (180 °) is set;

(b) be provided with and need the sampling number of repetition M in the measurement;

(c) robot calculator 42 at the uniform velocity rotates by control box 41 driven in rotation devices 13 drive phase compensators 14, and angular velocity is ω _C

(d) angular encoder 15 equal angles at interval (180 °/export a position signalling pulse to enter control box 41 N), control box sends a synchronous triggering signal to imageing sensor 33, makes it begin to carry out the time integral exposure of optical imagery;

(e) data acquisition unit 43 is transferred to robot calculator 42 to the signal from imageing sensor 33 after conversion, carries out computing, processing and/or the storage of view data then;

(f) repeating step (d)-(e) reaches N * M until number of samples;

(g) the luminous energy value that measures according to each pixel in the image calculates the ellipsometric parameter value (ψ and Δ) of corresponding region on the sample.

Because phase compensator 14 is rotated always, institute's image taking sensor 33 need obtain real-time trigger pip, by control box 41 is electrically connected with imageing sensor 33,41 pairs of imageing sensors 33 of control box are triggered firmly, (existing ellipsometry imaging device is after equiphase compensator 14 forwards a certain position to and stops and not adopting 42 pairs of imageing sensors of robot calculator 33 in the existing ellipsometry imaging device to carry out the mode of soft triggering, trigger imageing sensor 33 again, make it begin to carry out the time integral exposure of optical imagery, adopt soft triggering also can not produce the problem of trigger delay under this mode), can reduce the generation of trigger delay, guarantee to control precision.

Claims (25)

1. an ellipsometry imaging method that adopts rotating compensator integration sampling is characterized in that, described method comprises the steps:

Steps A: system is provided with;

Steps A specifically comprises:

A., the sampling unit number N that angle is divided equally in 180 ° of 1 sampling periods is set;

B. be provided with and need the sampling number of repetition M in the measurement;

Step B: imageing sensor carries out the time integral exposure;

Step B specifically comprises:

C. robot calculator (42) at the uniform velocity rotates by drive control box (41) driving phase compensator universal stage (13);

D. the pulse signal synchronous triggering imageing sensor (33) of 180 °/N ground, angular encoder (15) equal angles interval outgoing position signal pulse after control box (41) is handled carries out the time integral exposure of optical imagery, forms electronic image then;

Step C: data are changed, transmit, handled and store;

Step C specifically comprises:

E. data acquisition unit (43) is given robot calculator (42) digital data transmission from imageing sensor (33), is carried out computing, processing and/or the storage of view data then by robot calculator (42);

F. repeating step d.-e. is until finishing number of samples N * M;

Step D: the data that collect are calculated;

Step D is specially:

G. the luminous energy value that measures according to each pixel in the image and the relation of ellipsometric parameter, the ellipsometric parameter value of corresponding region on the calculation sample.

2. ellipsometry imaging device that adopts rotating compensator integration sampling, described device comprises:

Incident unit (1) is used to produce collimation, monochrome, the controlled polarized lightwave of polarization state, and oblique incidence is to sample surfaces;

Outgoing unit (3), the optical axis of the optical axis of described outgoing unit (3) and described incident unit (1) are used for receiving the reflected light from sample (20), and its polarization state is modulated, and obtain the ellipse inclined to one side image of sample (20);

Data acquisition process unit (4) is used to gather the data of described outgoing unit (3) generation and handle;

It is characterized in that incident unit (1) specifically comprises:

Incident arm (16) is used to carry various elements, makes its coaxial arrangement;

Collimated monochromatic light generator (11) coaxially is installed on the described incident arm (16) with the incident cell optic axis, is used to produce and expand the quasi-monochromatic light output of collimation;

First linear polarization (12) coaxially is installed on the described incident arm (16) with the incident cell optic axis, is positioned at described collimated monochromatic light generator (11) back, is used for detecting light beam is transformed to linearly polarized photon;

Universal stage (13) coaxially is installed on the described incident arm (16) with the incident cell optic axis, is positioned on first linear polarization (12) light path afterwards, can be used to make element fixed thereon around the rotation of incident cell optic axis around the rotation of incident cell optic axis;

Phase compensator (14), coaxially be installed on the universal stage (13) with the incident cell optic axis, can be used on two mutually perpendicular directions, producing a phase-delay difference, thereby change the polarization polarization state of light with universal stage (13) jointly around the rotation of incident cell optic axis;

Angular encoder (15) coaxially is installed on the described universal stage (13) with the incident cell optic axis, can be used to write down the position angle of phase compensator (14) with universal stage (13) jointly around the rotation of incident cell optic axis;

Described outgoing unit (3) specifically comprises:

Outgoing arm (36) is used to carry various elements, makes its coaxial arrangement;

Second linear polarization (31) coaxially is installed on the outgoing arm (36) with the outgoing cell optic axis, is used for the direct reflection polarization state of sample (20) is modulated into linearly polarized photon;

Imaging lens (32), coaxially be installed on the outgoing arm (36) with the outgoing cell optic axis, this imaging lens (32) is according to the requirement of imaging magnification, coaxially be placed on the emergent light axis second linear polarization (31) afterwards, or be placed between sample (20) and second linear polarization (31), be used for sample is carried out imaging;

Imageing sensor (33) is used to receive sample through the optics real image that imaging lens became, and is translated into electric signal;

Described data acquisition process unit (4) specifically comprises:

Control box (41) is electrically connected with universal stage (13), is used for driven in rotation platform (13) drive phase compensator (14) and at the uniform velocity rotates; Control box (41) is electrically connected with angular encoder (15), is used for receiving the position signalling from angular encoder (15); Control box (41) is electrically connected with imageing sensor (33), is used for the angle signal of angular encoder (15) changed into can triggering imageing sensor (33) and beginning the pulse signal of integration that exposes, thereby imageing sensor (33) is triggered control firmly;

Data acquisition unit (43), and imageing sensor (33) electrical connection are used for the picture signal that imageing sensor (33) collects is converted to the electronic signal that robot calculator (42) can receive;

Robot calculator (42) is used for the motion control and the data processing of total system; Robot calculator (42) is electrically connected with data acquisition unit (43), sends the steering order of data acquisition on the one hand, receives the view data from data acquisition unit (43) on the other hand; Robot calculator (42) is electrically connected with control box, the motion of parts in the control system, and reception is from the state feedback information of device;

Described data acquisition process unit (4) triggers the ellipse inclined to one side image that outgoing unit (3) obtains sample (20) by the mode of hard triggering.

3. according to the described ellipsometry imaging device of claim 2, it is characterized in that: described control box (41) comprises the receiving trap of motion control card, motor driver, position feedback device at least; Wherein motion control card is electrically connected with the receiving trap of robot calculator (42), motor driver and position feedback device respectively, motion control card carries out motion control issuing motor driver from the instruction of robot calculator (42) after by electronic switch, and passing to computing machine from the position command of position feedback device; Motor driver is electrically connected with motor, and drive motor produces motion; The detectable signal of the receiving trap receiving position ultramagnifier of position feedback device, and signal passed to motion control card.

4. according to the described ellipsometry imaging device of claim 2, it is characterized in that: described phase compensator (14) is for producing the optical anisotropy device of certain phase-delay difference on two mutually perpendicular directions.

5. according to the described ellipsometry imaging device of claim 4, it is characterized in that: described phase compensator (14) is mica waveplate, quartz wave-plate, liquid crystal wave plate.

6. according to the described ellipsometry imaging device of claim 2, it is characterized in that: described first linear polarization (12) and second linear polarization (31) are for being transformed into any light wave the polarizer of linearly polarized light.

7. according to the described ellipsometry imaging device of claim 6, it is characterized in that: described first linear polarization (12) and second linear polarization (31) are dichroism linear polarization or Glan-Taylor polarizing prism or Glan-Thompson polarizing prism.

8. according to the described ellipsometry imaging device of claim 2, it is characterized in that: described imageing sensor (33) is for utilizing the time integral mode inciding the array photoelectricity converted image sensor that light distribution signal on its image sensing surface changes into electric signal.

9. according to the described ellipsometry imaging device of claim 8, it is characterized in that: described imageing sensor (33) is charge-coupled image sensor, cmos image sensor.

10. according to the described ellipsometry imaging device of claim 2, it is characterized in that: described collimated monochromatic light generator is formed by continuous spectrum light source and light-splitting device and collimation lens combination, or is formed by monochromatic light emitters part and collimation lens combination.

11. according to the described ellipsometry imaging device of claim 10, it is characterized in that: described light-splitting device is spectrometer or optical filter, described monochromatic light emitters part is laser instrument or light emitting diode.

12. according to the described ellipsometry imaging device of claim 2, it is characterized in that: described angular encoder (15) is the unit that can be divided into circumference several equal angles spacings, and the scrambler that position signalling is exported by coded system.

13. according to the described ellipsometry imaging device of claim 12, it is characterized in that: described angular encoder (15) is photoelectric encoder, magnetic coder.

14. an ellipsometry imaging device that adopts rotating compensator integration sampling, described device comprises:

Incident unit (1) is used to produce collimation, monochrome, the controlled polarized lightwave of polarization state, and oblique incidence is to sample surfaces;

Outgoing unit (3), the optical axis of the optical axis of described outgoing unit (3) and described incident unit (1) are used for receiving the reflected light from sample (20), and its polarization state is modulated, and obtain the ellipse inclined to one side image of sample (20);

Data acquisition process unit (4) is used to gather the data of described outgoing unit (3) generation and handle;

It is characterized in that described incident unit (1) specifically comprises:

Incident arm (16) is used to carry various elements, makes its coaxial arrangement;

Collimated monochromatic light generator (11) coaxially is installed on the described incident arm (16) with the incident cell optic axis, is used to produce and expand the quasi-monochromatic light output of collimation;

First linear polarization (12) coaxially is installed on the described incident arm (16) with the incident cell optic axis, is positioned at described collimated monochromatic light generator (11) back, is used for detecting light beam is transformed to linearly polarized photon;

Described outgoing unit (3) specifically comprises:

Outgoing arm (36) is used to carry various elements, makes its coaxial arrangement;

Universal stage (13) coaxially is installed on the described outgoing arm (36) with the outgoing cell optic axis, can lay out to penetrate the cell optic axis rotation, is used to make element fixed thereon around the rotation of outgoing cell optic axis;

Phase compensator (14), coaxially be installed on the described universal stage (13) with the outgoing cell optic axis, can lay out jointly with universal stage (13) and penetrate the cell optic axis rotation, be used on two mutually perpendicular directions, producing a phase-delay difference, thereby change the polarization polarization state of light;

Angular encoder (15) coaxially is installed on the described universal stage (13) with the outgoing cell optic axis, can lay out jointly with universal stage (13) and penetrate the cell optic axis rotation, is used to write down the position angle of phase compensator (14);

Second linear polarization (31) coaxially is installed on the outgoing arm (36) with the outgoing cell optic axis, is used for the direct reflection polarization state of sample (20) is modulated into linearly polarized photon;

Imaging lens (32), coaxially be installed on the outgoing arm (36) with the outgoing cell optic axis, this imaging lens (32) is according to the requirement of imaging magnification, coaxially be placed on the emergent light axis second linear polarization (31) afterwards, or be placed between sample (20) and second linear polarization (31), be used for sample is carried out imaging;

Imageing sensor (33) is used to receive sample through the optics real image that imaging lens became, and is translated into electric signal;

Described data acquisition process unit (4) specifically comprises:

Control box (41) is electrically connected with universal stage (13), is used for driven in rotation platform (13) drive phase compensator (14) and at the uniform velocity rotates; Control box (41) is electrically connected with angular encoder (15), is used for receiving the position signalling from angular encoder (15); Control box (41) is electrically connected with imageing sensor (33), is used for the angle signal of angular encoder (15) changed into can triggering imageing sensor (33) and beginning the pulse signal of integration that exposes, thereby imageing sensor (33) is triggered control firmly;

Data acquisition unit (43), and imageing sensor (33) electrical connection are used for the picture signal that imageing sensor (33) collects is converted to the electronic signal that robot calculator (42) can receive;

Robot calculator (42) is used for the motion control and the data processing of total system; Robot calculator (42) is electrically connected with data acquisition unit (43), sends the steering order of data acquisition on the one hand, receives the view data from data acquisition unit (43) on the other hand; Robot calculator (42) is electrically connected with control box, the motion of parts in the control system, and reception is from the state feedback information of device; Described data acquisition process unit (4) triggers the ellipse inclined to one side image that outgoing unit (3) obtains sample (20) by the mode of hard triggering.

15. according to the described ellipsometry imaging device of claim 14, it is characterized in that: described control box (41) comprises the receiving trap of motion control card, motor driver, position feedback device at least; Wherein motion control card is electrically connected with the receiving trap of robot calculator (42), motor driver and position feedback device respectively, motion control card carries out motion control issuing motor driver from the instruction of robot calculator (42) after by electronic switch, and passing to computing machine from the position command of position feedback device; Motor driver is electrically connected with motor, and drive motor produces motion; The detectable signal of the receiving trap receiving position ultramagnifier of position feedback device, and signal passed to motion control card.

16. according to the described ellipsometry imaging device of claim 14, it is characterized in that: described phase compensator (14) is for producing the optical anisotropy device of certain phase-delay difference on two mutually perpendicular directions.

17. according to the described ellipsometry imaging device of claim 16, it is characterized in that: described phase compensator (14) is mica waveplate, quartz wave-plate, liquid crystal wave plate.

18. according to the described ellipsometry imaging device of claim 14, it is characterized in that: described first linear polarization (12) and second linear polarization (31) are for being transformed into any light wave the polarizer of linearly polarized light.

19. according to the described ellipsometry imaging device of claim 18, it is characterized in that: described first linear polarization (12) and second linear polarization (31) are dichroism linear polarization or Glan-Taylor polarizing prism or Glan-Thompson polarizing prism.

20. according to the described ellipsometry imaging device of claim 14, it is characterized in that: described imageing sensor (33) is for utilizing the time integral mode inciding the array photoelectricity converted image sensor that light distribution signal on its image sensing surface changes into electric signal.

21. according to the described ellipsometry imaging device of claim 20, it is characterized in that: described imageing sensor (33) is charge-coupled image sensor, cmos image sensor.

22. according to the described ellipsometry imaging device of claim 14, it is characterized in that: described collimated monochromatic light generator is formed by continuous spectrum light source and light-splitting device and collimation lens combination, or is formed by monochromatic light emitters part and collimation lens combination.

23. according to the described ellipsometry imaging device of claim 22, it is characterized in that: described light-splitting device is spectrometer or optical filter, described monochromatic light emitters part is laser instrument or light emitting diode.

24. according to the described ellipsometry imaging device of claim 14, it is characterized in that: described angular encoder (15) is the unit that can be divided into circumference several equal angles spacings, and the scrambler that position signalling is exported by coded system.

25. according to the described ellipsometry imaging device of claim 24, it is characterized in that: described angular encoder (15) is photoelectric encoder, magnetic coder.

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