CN100398980C - Three-dimensional super-resolution confocal array scanning and micro-detecting method and device - Google Patents

Abstract

The present invention relates to an optical array confocal super resolution micro-three-dimensional detecting device, which comprises a point light source, a collimation lens, a microlens array, a pinhole array, an extender lens, a polarization spectroscope, a quarter-wave plate, a binary pupil filter, an objective, an objective table, a collecting lens, a detecting pinhole array and an area array CCD which are orderly arranged and positioned on a central optical axis of an optical system, wherein parallel light is formed by the point light source to shoot on the microlens array, and a point light source array is formed on the focal surface of the extender lens by the pinhole array. Polarizing light is formed by the polarization spectroscopeand the quarter-wave plate and is irradiated on the surface of an object to be measured by the binary pupil filter and the objective. The polarizing light is reflected by the surface of the object to be measured and returns according to an original light path. After passing through the polarization spectroscope, the reflection light is completely reflected on the collecting lens and finally reaches the area array CCD by the pinhole array. Signals are collected by the area array CCD. The present invention also compromises a method for detecting and measuring three-dimensional surfaces and three-dimensional structures by using one detector.

Description

Three-dimensional super-resolution confocal array scanning micro-detecting method and device

Technical field

The present invention relates to surface three dimension microtexture field of measuring technique, particularly a kind of three-dimensional super-resolution confocal array scanning micro-detecting method and device.

Background technology

Confocal microscope is with remarkable advantages such as its noncontact, high resolving power, three-dimensional digital imagings, be widely used in fields such as medicine, biology, photoetching, material, the key factor that influences the confocal microscope system development is measurement range, measuring speed and three-dimensional resolving power thereof.Micro-optic and microelectronic flourish has promoted binary optical elements to make and process technology moves to maturity gradually, makes conventional optical systems towards miniaturization, array, integrated direction development.Therefore, binary optical elements being introduced making the two organic combination in traditional confocal microscope system, is to solve its three-dimensional measurement speed, Measurement Resolution and the conflicting effective way of measurement range three.

At present, the method that adopts microlens array to improve the cofocus scanning performance mainly contains two kinds of forms, and a kind of is the object lens that replace conventional confocal microscopes with microlens array, and a kind of is to utilize microlens array to form the lattice array lighting source, replaces the single-point lighting source.The former is shorter because of the focal length of microlens array, though the higher measurement range of precision is less relatively; And the latter is thrown light on owing to employing array beams point, the position difference of every bundle light off-axis, and corresponding sampled point not only produces certain astigmatism, but also can depart from ideal image point, thereby has reduced the measuring accuracy of system.

Summary of the invention

The present invention be directed to above-mentioned problems of the prior art, a kind of binary micro optical element is introduced in the confocal microscopy, a kind of novel micro-three-dimensional detection method of the confocal super-resolution of optics array and device are proposed, and by the binary iris filter, improve system's three-dimensional measurement precision under the array lighting condition, solve the contradiction between measuring speed, measurement range and the measuring accuracy three.

For achieving the above object, the invention provides the micro-three-dimensional detection device of the confocal super-resolution of a kind of optical array, described device comprises the pointolite that is arranged in order on the central optical axis that is positioned at optical system, collimation lens, microlens array and pinhole array, extender lens, polarization spectroscope, quarter wave plate, binary iris filter, object lens, objective table, collecting lens, detecting pinhole array and area array CCD; Pointolite forms directional light by collimation lens and incides on the microlens array, on the extender lens focal plane, form pointolite array through pinhole array again, through polarization spectroscope and quarter wave plate, form polarized light, shine the measured object surface through binary iris filter and object lens again, through the measured object surface reflection, return by original optical path, reflected light is all reflexed on the collecting lens behind polarization spectroscope, arrive at last on the area array CCD through pinhole array, signal is gathered by area array CCD.

The present invention also provides a kind of method of using a detector to survey and measure three-dimensional surface and three-dimensional structure,, described detector comprises optic probe, objective table, area array CCD and computing machine, optical measuring head comprises spotlight source device, collimation lens, microlens array and pinhole array, extender lens, polarization spectroscope, quarter wave plate, the binary iris filter, object lens, collecting lens, detecting pinhole array; Described method comprises the following steps: to utilize microlens array to produce the detecting light beam array, to realize multi-beam parallel detection and the measurement to sample;

By polarization spectroscope detecting light beam is converted to polarized light;

Utilize the binary iris filter that each road light beam of beam array is modulated, change the light distribution characteristic of space exploration, measure to realize three-dimensional super-resolution;

On optical axis direction measured object being carried out axial scan surveys; Reflected light arrives quarter wave plate through object lens, binary iris filter, and 90 ° of change of polarized direction reflex to light collecting lens through polarization spectroscope, arrive the area array CCD surface at last;

In computing machine,, draw sample 3 d surface topography measurement result according to the axial curve of light distribution and each horizontal detection position.

Further, optimize binary iris filter parameter, improve the microscopical three-dimensional resolution characteristic of confocal array by Computer Simulation.

Further, described scan mode is that optical measuring head carries out the primary optical axis scanning direction, and the loading worktable is made horizontal two-dimentional micrometric displacement and moved.

Further, described scan mode is that the loading worktable is made three-dimensional micrometric displacement and moved, and optical measuring head is motionless.

The present invention utilizes the micro optical element array to realize the multi-pass synchro measure, effectively improves confocal micro-measurement speed; Introduce novel binary iris filter, effectively improve the three-dimensional resolution characteristic of each light path, guaranteed measuring accuracy, remedied the loss of significance that causes by the pointolite off-axis illumination; Again owing to added the binary iris filter, the light intensity response curve of sharpening space exploration picture point greatly, thereby the spacing of dwindling confocal array have effectively improved the detection efficiency of optical system; And this apparatus structure is simple, shared same microcobjective of each light path and same iris filter, and its cost of manufacture is relatively low.

Three-dimensional super-resolution confocal array scanning micro-detecting method provided by the invention and device can be realized the confocal detection of multi-beam parallel, and have very high three-dimensional super-resolution ability.Utilize microlens array and pinhole array to realize the quick scanning survey of multidiameter delay, shared same microcobjective, and adding binary iris filter make each light path all have the three-dimensional super-resolution detectivity.The present invention combines the array confocal technology with the optical ultra-discrimination technology is organic, can realize the intensive detection of the super nearly spacing of confocal array, can effectively improve the efficient of its three-dimensional measurement, be specially adapted to live width, the step height measurement of large scale integrated circuit, and the detection and the measurement of the three-dimensional surface of Microstructure Optics element and micromechanics three-dimensional structure, the advantage that the present invention has on a large scale, high precision, quick three-dimensional are measured.

Three-dimensional super-resolution confocal array scanning micro-detecting method of the present invention and apparatus features and principle will elaborate in its embodiment in conjunction with the accompanying drawings.

Description of drawings

The confocal super-resolution three-dimensional measuring apparatus of Fig. 1 optics array structural representation.

Fig. 2 three-dimensional super-resolution iris filter.

Fig. 3 three-dimensional super-resolution iris filter resonse characteristic.

The axial light intensity distribution character in each road curve when Fig. 4 does not use super-resolution pupil filter.

Each path was not to the light distribution family curve when Fig. 5 used super-resolution pupil filter.

The radially light distribution response curve of the arbitrary road of Fig. 6 optics array under different pupil parameters.

The axial light distribution response curve of the arbitrary road of Fig. 7 optics array under different pupil parameters.

Embodiment

The structure of present embodiment three-dimensional super-resolution confocal array scanning microscopic detector as shown in Figure 1, this device comprises: laser instrument 1, collimation lens 2, lenticule and pinhole array 3, lens 4, polarization spectroscope 5, quarter wave plate 6, binary iris filter 7, microcobjective 8, measured object 9, micro-displacement work table 10, condenser 11, detecting pinhole array 12, area array CCD 13, micrometric displacement driving control system 14, computing machine 15 and micrometric displacement inductance sensor 16.

The main devices model and the parameter of present embodiment three-dimensional super-resolution confocal array scanning micro-detecting method and device are as follows:

Measure object lens 8 in the present embodiment and select 40 * 0.65 and 60 * 0.85 flat field achromatic micro objective for use.Microlens array is: Unit 40 * 40, unit interval are 150um, and focal length is 4mm, and quantizing number of steps is 8.CCD face battle array 12 is the CV-A1 camera of Denmark JAI company, 1392 * 1040 unit of face array element, unit size 4.65um2.

The driver of micro-displacement work table 17 adopt that U.S. NEWFOCUS company produces on a large scale, high stability Picomotor (micro-displacement driver) driver, be equipped with the nano level micrometric displacement feed arrangement that 5: 1 flexible hinge work bench of scale down is formed.Z is finished by high-precision micro displacement inductance sensor 16 to the displacement measurement of positioning table, thereby realizes the 2nm hi-Fix.

Binary iris filter 7 adopts amplitude type variable annular wave filter, sees accompanying drawing 2,3.

Principle of work of the present invention is as described below: become to parallel beam through collimation lens 2 from the light of laser instrument 1 and shine lenticule and pinhole array 3, the lenticule focal position is on lens 4 focal planes, the diverse location pointolite forms the dip-parallel light of different angle through lens 4, through described iris filter 7 and microcobjective 8, arrive the measured object surface.Computing machine 15 is formed closed-loop digital control systems with micrometric displacement driving control device 14, high-precision micro displacement inductance sensor 16, accurately controls micro-displacement work table and carries out Z and move to scanning.When being detected thing 9 surfaces in focal plane of lens, the light intensity maximum that area array CCD 13 is accepted, light intensity reduces when out of focus, can obtain the out of focus distance of measured surface by intensity properties curve (being the relation curve of axial light intensity and defocusing amount) linear segments, combine with micro-displacement sensor 16 measured values, thus by Z to scanning, and through the data processing of computing machine, the tested surface three-dimensional optical information translation that area array CCD 13 obtains can be become numerical information, thereby obtain the three-dimensional dimension of tested surface.

Measuring principle of the present invention is based on the confocal microscopic imaging principle, is to utilize object lens and the confocal point of collector lens, and pointolite and point probe are in conjugate position each other.In fact the object lens of reflection-type confocal system and collector lens are same lens, thereby on space exploration, its light distribution can be expressed as

$I(u,v)={\left|h_1(u,v)\right|}^2\left[{\left|h_2(u,v)\right|}^2{\⊗}_{3}D\left(v\right)\right],$

D in the formula (v) be the intensity sensitivity of detector, if get normal value, then:

$I(u,v)={\left|h(u,v)\right|}^4={\left|2{\∫}_0^{1}P\left(\mathrm{\ρ}\right)e^{\frac{j{u}^2\mathrm{\ρ}}{2}}{J}_0\left(\mathrm{\ρv}\right)\mathrm{\ρd\ρ}\right|}^4---\left(1\right)$

With simple microscope contrast as can be known, its lateral resolution is 1.4 times of simple microscope of same holes coke ratio, and has axial resolution simultaneously.

Further, the present invention utilizes microlens array and pinhole array, and original single point light source is expanded to pointolite array, can form the multi-beam parallel synchronized sampling.The optical field distribution characteristic and the single-point confocal system of its imaging space are different, and it is axial, the radial light field distribution is respectively:

$U_3(u,0)=\frac{\mathrm{<figure-callout\; id="1"\; label="M\; d"\; filenames="C20051000721800123.png,C20051000721800131.png"\; state="\{\{state\}\}">M</figure-callout>}}{d_{}^{}}{\&Integral;}_0^{1}P\left(\mathrm{\&rho;}\right)\exp [-\mathrm{iu}{\mathrm{\&rho;}}^2/2-\mathrm{ik}\frac{{\mathrm{<figure-callout\; id="2"\; label="a"\; filenames="C20051000721800132.png,C20051000721800133.png"\; state="\{\{state\}\}">a</figure-callout>}}^2{\mathrm{\&rho;}}^2{\mathrm{<figure-callout\; id="2"\; label="sin"\; filenames="C20051000721800132.png,C20051000721800133.png"\; state="\{\{state\}\}">sin</figure-callout>}}^2\mathrm{\&theta;}}{2d_2}]2\mathrm{\&pi;}{J}_0(k{a}^2{\mathrm{\&rho;}}^2{\sin }^2\mathrm{\&theta;}/4d_2)\mathrm{\&rho;d\&rho;}---\left(2\right)$

$U_3(0,v)=\frac{\mathrm{<figure-callout\; id="1"\; label="M\; d"\; filenames="C20051000721800123.png,C20051000721800131.png"\; state="\{\{state\}\}">M</figure-callout>}}{d_{}^{}}{\&Integral;}_0^{1}P\left(\mathrm{\&rho;}\right)\exp [-\mathrm{ik}\frac{{\mathrm{<figure-callout\; id="2"\; label="a"\; filenames="C20051000721800132.png,C20051000721800133.png"\; state="\{\{state\}\}">a</figure-callout>}}^2{\mathrm{\&rho;}}^2{\mathrm{<figure-callout\; id="2"\; label="sin"\; filenames="C20051000721800132.png,C20051000721800133.png"\; state="\{\{state\}\}">sin</figure-callout>}}^2\mathrm{\&theta;}}{2d_2}]2\mathrm{\&pi;}{J}_0\left(\mathrm{v\&rho;}\right)\mathrm{\&rho;d\&rho;}---\left(3\right)$

Can get space exploration axially, light distribution radially:

$I(u,0)={\left|2{\&Integral;}_0^1{P}_{\mathrm{effu}}\left(\mathrm{\&rho;}\right)\exp \right[-\mathrm{iu}{\mathrm{\&rho;}}^2/2\left]\mathrm{\&rho;d\&rho;}\right|}^4---\left(4\right)$

$I(0,v)={\left|2{\&Integral;}_0^1{P}_{\mathrm{effv}}\left(\mathrm{\&rho;}\right)J_0\left(\mathrm{v\&rho;}\right)\mathrm{\&rho;d\&rho;}\right|}^4---\left(5\right)$

Introduce equivalent pupil function Peff (ρ) in the formula, this function is relevant apart from optical axis distance with pointolite, and is simultaneously relevant with the characteristic of super-resolution binary iris filter.

For amplitude type binary iris filter, be exactly position and size by the logical light belt that changes wave filter, to change the integral domain of space exploration, see (2), (3) formula, thereby change the light distribution of space exploration.As accompanying drawing 2, its variable element of amplitude binary iris filter: ε, ω are ring radius adjustability coefficients, 0.5＜ε＜1,0＜ω＜1, and c is a center light leak coefficient, the binary iris filter can be used following function representation in this specific embodiment:

$q\left(\mathrm{\&xi;}\right)=\left\{\begin{array}{cc}\mathrm{rect}\left(\mathrm{\&xi;}\right)-\mathrm{rect}\left[\frac{\mathrm{\&xi;}+(\mathrm{\&epsiv;}-0.5)\mathrm{\&omega;}}{\mathrm{\&omega;}}\right]& 0\&le;\mathrm{\&xi;}\&le;0.5\\ c\{\mathrm{rect}\left(\mathrm{\&xi;}\right)-\mathrm{rect}[\frac{\mathrm{\&xi;}+(\mathrm{\&epsiv;}-0.5)\mathrm{\&omega;}}{\mathrm{\&omega;}}\left]\right\}& 0>\mathrm{\&xi;}\&GreaterEqual;-0.5\end{array}\right.---\left(6\right)$

According to super-resolution theory, 1) half-shadow value wide (HWHM) compares G; 2) focus strength S trehl is than S:3) main lobe intensity and side lobe intensity be than M[7] [8] [9].Utilize in view of the above axially with radially two super-resolution factor GT, GA set up objective function G3D=GA2GT.Pass through Computer Simulation thus,, calculate each light path objective function G3D by changing the iris filter adjustable parameter, and obtain the parameters optimization of iris filter according to simulation curve, choose iris filter selection of parameter ω=0.56 in the specific embodiment, c=0.6, ε=0.82.Its super-resolution effect is seen accompanying drawing 6, accompanying drawing 7.

Although adopt the confocal array method to improve the speed of measuring, but because the influence of off axis point light illumination, make the three-dimensional resolving power of system descend to some extent, in system, introduce the binary iris filter for this reason, and, the parameter of iris filter is optimized according to the super-resolution evaluation function, effectively compressional axis to half high half-breadth of both direction radially than (HWMH), simultaneously by the effect of confocal characteristic, effective suppressed sidelobes, the three-dimensional resolution characteristic of raising system.

According to its strength distribution curve, in its linearity range, can measure the surface topography and the three-dimensional microcosmic size of sample at space exploration.

Below in conjunction with the accompanying drawings the specific embodiment of the present invention and test effect are described; but these explanations can not be understood that to have limited scope of the present invention; protection scope of the present invention is limited by the claims of enclosing, and any change of carrying out on claim of the present invention basis all is protection scope of the present invention.

Claims (7)

1. three-dimensional super-resolution confocal array scanning microscopic detector, be included in the pointolite that is arranged in order on the central optical axis, collimation lens, microlens array and pinhole array, extender lens, polarization spectroscope, quarter wave plate, microcobjective, collecting lens, detecting pinhole array and area array CCD, pointolite forms directional light by collimation lens and incides on the microlens array, on the extender lens focal plane, form pointolite array through pinhole array again, through polarization spectroscope and quarter wave plate, form polarized light, shine the measured object surface through microcobjective again; Incident light returns by original optical path through the measured object surface reflection, and reflected light is all reflexed on the collecting lens behind polarization spectroscope, arrives at last on the area array CCD through the detecting pinhole array, by area array CCD signal is gathered; It is characterized in that: also comprise a binary iris filter, described binary iris filter is positioned between 1/4 slide and the microcobjective; Described polarized light is modulated behind described binary iris filter, and the light after the modulation shines the measured object surface through microcobjective again.

2. three-dimensional super-resolution confocal array scanning microscopic detector according to claim 1 is characterized in that: described binary iris filter is amplitude type, phase-type or mixed type binary optical device.

3. three-dimensional super-resolution confocal array scanning microscopic detector according to claim 1 is characterized in that: described microlens array is continuous relief or many steps microlens array.

4. the method for three-dimensional surface and three-dimensional structure is surveyed and measured to detector of a use, described detector comprises spotlight source device, collimation lens, microlens array and pinhole array, extender lens, polarization spectroscope, quarter wave plate, the binary iris filter, microcobjective, collecting lens, detecting pinhole array, area array CCD and computing machine, described method comprises the following steps:

1) utilize microlens array to produce the detecting light beam array, to realize multi-beam parallel detection and measurement to sample;

2) by polarization spectroscope detecting light beam is converted to polarized light;

3) utilize the binary iris filter that each road light beam of beam array is modulated, change the light distribution characteristic of space exploration, measure to realize three-dimensional super-resolution;

4) on optical axis direction measured object being carried out axial scan surveys; Reflected light arrives quarter wave plate through object lens, binary iris filter, and 90 ° of change of polarized direction reflex to collecting lens through polarization spectroscope, arrive the sampled detector surface at last;

5) in computing machine according to axially light distribution and the radially curve of light distribution, draw the measurement result of sample 3 d surface topography.

5. method according to claim 4 wherein, draws the binary iris filter parameter of optimization by Computer Simulation, improves the microscopical three-dimensional resolution characteristic of confocal array.

6. method according to claim 4, wherein, described scan mode is to carry out the primary optical axis scanning direction by optical measuring head, the loading worktable is static.

7. method according to claim 4, wherein, described scan mode is equidistantly to be moved by the loading worktable optical axis direction of deciding, optical measuring head is motionless.

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