CN103398666B - A kind of dislocation of the interlayer for double-deck periodic micro structure method of testing - Google Patents

Abstract

A method for testing layer-to-layer dislocation of a double-layer periodic microstructure, used to test the layer-to-layer dislocation spacing of a double-layer grating structure , including layer dislocation spacing-diffraction light equation F fitting process, measuring fixed layer dislocation spacing The zero-order diffraction light of the grating below focuses on the parameter and obtains the wavelength curve of the concerned parameter; further obtains the wavelength curve group of the concerned parameter corresponding to the layer dislocation spacing value (δ0, δ1, δ2...) defined by a set of arithmetic discrete sequences; In the Curves group select With Change, pay attention to the wavelength interval FQ that is most sensitive to parameter changes, and fit the average layer dislocation distance in a specific wavelength range-diffraction light equation F2; after obtaining F2, when measuring the layer dislocation distance, use the narrow spectrum polarization within the FQ interval The light source measures the average value of the concerned parameter of the zero-order diffracted light, and the layer dislocation spacing of the double-layer structure to be tested can be obtained.

Description

A method for testing layer-to-layer dislocation for double-layer periodic microstructures

technical field

The invention belongs to the field of optical engineering, and relates to an interlayer dislocation test method for double-layer periodic microstructures.

Background technique

In the semiconductor and other microelectronics industries, multilayer structures have been widely used. In this structure, no matter in plate making, photolithography, or chip after processing, the test of interlayer misalignment is very important, and the magnitude of interlayer misalignment is at the micron, submicron or even nanometer level. There are many methods for micron-level testing, including image and non-image methods. Among them, the image method is the simplest, judging the distance between the two-layer structure lines from the directly observed image and the magnification. But this method has its own weaknesses: First, it requires complex equipment and test rings - electron microscopes and vacuum environments; secondly, the vibration of the test platform has a relatively large impact on the test, especially for modern semiconductor integrated circuits, etc. With the rapid development of microelectronics technology, the line size is getting smaller and smaller, and the requirements for interlayer misalignment are getting higher and higher. The method of using image observation to realize the test is also difficult to meet the demand in terms of accuracy.

At present, the non-image test is the main method to realize the interlayer misalignment test. This method has been developed for many years. In order to facilitate the measurement, a periodic grating with the same period length is usually constructed on the two layers involved in the measured layer spacing misalignment. As shown in Figures 1 to 2, periodic gratings are periodically interlaced with two different light-transmitting materials. By projecting a parallel incident light at a certain angle on the surface of the tested sample with a two-layer periodic structure, the grating Reflection and diffraction occur, and its intensity can be calculated by the simulation of the optical field, combined with the test of the spectrum, the test/analysis of certain structural parameters can be realized. The zero-order reflection spectrum intensity is related to the interlayer dislocation, so it can be used to test the interlayer dislocation. A variety of testing methods based on this principle have been realized. For example, in US Patent 4757207, Chappelow et al. used a non-diffraction method to realize non-image testing, which can realize testing when the period size is equal to or slightly smaller than the wavelength. As the size of the microelectronics technology becomes smaller and smaller, it becomes more and more difficult for this method to meet the actual needs in terms of accuracy and so on. The test/analysis method that fully considers the diffraction effect and combines with the rigorous simulation calculation of the light wave electric field has become the main method. However, the method of direct detection lacks the comparison and calibration of the reflectivity (normalized reflection intensity) of different misalignment δ situations. Therefore, in US Patent 6699624, Niu et al. adopt the incident surface of the incident light in the vertical plane of the one-dimensional grating The spectral intensity test system, because this system can not distinguish between positive and negative dislocations, they first make the reverse version of the chip (or mask) to be tested, and then make the grating corresponding to the positive and negative version, through the test with the grating The comparison test determines the interlayer misalignment, and this method realizes the higher precision interlayer misalignment test. In US Patent 7289214B1, Li et al. adopted the method of diffracting the incident light at the spatial cone angle to realize the interlayer misalignment test. There was no change in the optical system, but the angle of the incident light was changed so that the incident surface of the light was not in the plane perpendicular to the grating. , which makes the calculation of the electric field more complicated, but such an optical system can realize the distinction between positive and negative interlayer dislocations. Although in most cases the test accuracy is slightly lower than the method in the patent of Niu et al., it does not need to make a reverse version, which simplifies the test process. Bischoff et al. proposed a new method in US Patent 6772084, which makes the sensitivity of zero-order diffraction to interlayer dislocation increase when the interlayer dislocation is about 1/4 period, which is conducive to improving the sensitivity of the test. A similar method is also described in "Anoveldiffraction based spectroscopic method for overlaymetrology, Proc. SPIE v5038, pp. 200-207" by Yang et al.

At present, these methods have been widely used in practical engineering applications, but with the development of semiconductor integrated circuits and other microelectronic technologies, the requirements for test accuracy are getting higher and higher. Therefore, it is very important to seek new testing and analysis methods to meet the needs of future technological development.

Contents of the invention

In order to overcome the technical defects of the traditional technology, the invention discloses a method for testing interlayer dislocation of a double-layer periodic microstructure.

A method for testing interlayer dislocation of a double-layer periodic microstructure according to the present invention is used to test the layer dislocation spacing δ of a double-layer grating structure, including a layer dislocation spacing-diffraction light equation F fitting process, the layer The fitting process of dislocation spacing-diffraction light equation includes the following steps:

Step 101. Use monochromatic polarized parallel light to enter the surface of the double-layer structure to be tested at a certain angle, and measure the parameter F of interest of the zero-order diffracted light; output monochromatic polarized light to obtain the parameter of interest under the fixed layer dislocation distance δ the wavelength curve;

Step 102. Only change the layer dislocation spacing δ in step 101 by arithmetic difference, repeat step 101 multiple times, and obtain a set of wavelength curves F1(λ, δ); where λ is the wavelength;

Step 103. In the curve group F1(λ, δ), select the wavelength interval FQ that is most sensitive to the change of the parameter concerned with the change of δ, and for any fixed wavelength within FQ, use several concerned parameters F corresponding to different layer dislocation distances The value of the parameter of interest at this wavelength is fitted with the function of the change of the interlayer dislocation distance; the wavelength is changed and the fitting is repeated, and the function F2(δ) of the attention parameter under each wavelength in the FQ interval is changed with the interlayer dislocation distance is obtained;

In the interlayer dislocation testing method for the double-layer periodic microstructure, after obtaining F2(δ), when measuring the interlayer dislocation distance, use any monochromatic polarized light in the FQ interval along the same incident angle as in step 101 Incident the double-layer structure to be tested, measure the concerned parameters of the zero-order diffracted light, and obtain the layer dislocation spacing of the double-layer structure to be tested according to the corresponding concerned parameter value and wavelength value.

Preferably, the parameter of interest is an ellipsometric parameter in ellipsometry, that is, the amplitude Δ and/or the argument Ψ of the ratio of the zero-order diffracted optical field in the two polarization directions tangential to normal to the incident plane.

Preferably, the incident direction of the monochromatic polarized light is: θ=φ=45 degrees, or θ=60 degrees, φ=90 degrees; θ is the angle between the incident direction and the vertical direction of the incident surface, and φ is The angle between the incident plane of the monochromatic diffracted light and the extension direction of the grating periodic arrangement.

Preferably, in the steps 101 to 102, for each layer dislocation distance, positive and negative values are respectively taken for measurement, and the two obtained values are averaged as the corresponding measurement value of the layer dislocation distance.

Preferably, in the step 103, the fitting is performed assuming that F2(δ) is a linear or quadratic nonlinear equation.

Preferably, in step 101, when measuring the attention parameter of the zero-order diffracted light, within a wavelength width range of Δλ with the measured wavelength as the wavelength center, the average value of the attention parameter of the zero-order diffracted light is taken, where Δλ is the incident The bandwidth of monochromatic polarized light.

Preferably, the measuring device is composed of a spectroscopic ellipsometer and a data processor connected with the spectroscopic ellipsometer.

A method for interlayer dislocation testing of double-layer periodic microstructures, used to test the layer dislocation spacing of two-dimensional periodic gratings, two sets of one-dimensional gratings perpendicular to each other are made at the same position of each layer structure as marking lines , using the method described in any one of the preceding items, by testing the layer dislocation spacing of two one-dimensional grating marking lines perpendicular to each other, the interlayer dislocation of the two-dimensional grating structure in two directions perpendicular to each other is obtained.

Using the interlayer dislocation test method for double-layer periodic microstructures of the present invention, by testing the relevant parameters of the light diffraction wave electric field in different polarization states, instead of the traditional test of light intensity, by testing different angles and different Spectrum test of parameters, select the most sensitive space angle and diffracted light parameters for interlayer dislocation, combined with simulation calculation and analysis of light diffraction wave electric field, to achieve high-precision interlayer dislocation test.

Description of drawings

Fig. 1 shows the schematic diagram of the interlayer dislocation structure and the incident coordinate system of the measuring beam according to the present invention;

Fig. 2 shows a schematic diagram of parameters related to layer dislocation spacing according to the present invention;

Fig. 3 shows a schematic diagram of the order of each component in the optical path of a specific embodiment of the present invention;

Fig. 4 shows the waveform diagrams of the various curves of the amplitude of the zero-order diffracted light varying with the wavelength of the incident light with different interlayer dislocation spacings in Embodiment 1 of the present invention;

Fig. 5 shows the waveform diagrams of various curves of the zero-order diffracted light argument angle changing with the incident light wavelength in Example 1 of the present invention with different interlayer dislocation spacings;

Fig. 6 shows the waveform diagrams of the various curves of the amplitude of the zero-order diffracted light varying with the wavelength of the incident light with different interlayer dislocation spacings in Embodiment 1 of the present invention;

The names of reference symbols in each figure are: 1. Light source 2. Polarizer 3. First rotary phase compensator 4. Second rotary phase compensator 5. Analyzer 6. Receiving spectrometer 7. Grating tunable filter.

Detailed ways

The specific embodiment of the present invention will be further described in detail below in conjunction with the accompanying drawings.

A method for testing interlayer dislocation of a double-layer periodic microstructure according to the present invention is used to test the layer dislocation spacing δ of the double-layer periodic structure, including the layer dislocation spacing-diffraction light equation F fitting process, the layer The fitting process of dislocation spacing-diffraction light equation includes the following steps:

Step 101. Use monochromatic polarized parallel light to enter the surface of the double-layer structure to be tested at a certain angle, and measure the parameter F of interest of the zero-order diffracted light; output monochromatic polarized light to obtain the parameter of interest under the fixed layer dislocation distance δ the wavelength curve;

Step 102. Only change the layer dislocation spacing δ in step 101 by arithmetic difference, repeat step 101 multiple times, and obtain a set of wavelength curves F1(λ, δ);

Step 103. In the curve group F1(λ, δ), select the wavelength interval FQ that is most sensitive to the change of the parameter concerned with the change of δ, and for any fixed wavelength within FQ, use several concerned parameters F corresponding to different layer dislocation distances The value of the parameter of interest at this wavelength is fitted with the function of the change of the interlayer dislocation distance; the wavelength is changed and the fitting is repeated, and the function F2(δ) of the attention parameter under each wavelength in the FQ interval is changed with the interlayer dislocation distance is obtained;

In the interlayer dislocation testing method for the double-layer periodic microstructure, after obtaining F2(δ), when measuring the interlayer dislocation distance, use any monochromatic polarized light in the FQ interval along the same incident angle as in step 101 Incident the double-layer structure to be tested, measure the concerned parameters of the zero-order diffracted light, and obtain the layer dislocation spacing of the double-layer structure to be tested according to the corresponding concerned parameter value and wavelength value.

For different layer dislocation distances, the relevant parameters of the zero-order diffracted light vary with the wavelength of the incident light. The basic realization idea of the present invention is to obliquely irradiate monochromatic polarized light on the double-layer surface, and measure the different layer dislocation distances. Find out the change law of the zero-order diffracted light related parameters with the wavelength of the incident light, and then for each wavelength, fit the layer dislocation spacing at this wavelength-diffraction light equation F2(δ), and then for any layer dislocation spacing, only the incident The monochromatic polarized light that is completely the same, that is, the wavelength, frequency, polarization state, and incident angle, etc., are all the same. By measuring the relevant parameters of the zero-order diffracted light, it can be brought into the equation F2(δ) to obtain the layer dislocation distance. Equation F2(δ) is obtained by mathematical fitting using multiple measured data points of different diffracted light parameters corresponding to different layer dislocation distances at a fixed wavelength. The wavelength interval FQ in which the diffracted light parameters are sensitive to changes in layer dislocation spacing should be selected to achieve high measurement accuracy.

In step 101, the wavelength curve of the parameter of interest under the fixed layer dislocation distance δ is obtained; in step 102, the layer dislocation distance is changed, and step 101 is repeated several times, and the wavelength curve of the concerned parameter F corresponding to the layer dislocation distance value δ of the arithmetic discrete sequence Group F1(λ, δ); in step 103, select the wavelength sensitive interval and fit the equation F2(δ).

Step 101 can preferably be simulated by software to reduce experiment costs. Before the simulation, the nk table of various materials constituting the grating is usually obtained by testing or other methods, that is, the curve of the complex refractive index changing with the wavelength λ, based on the nk table of various materials, the simulation is performed using simulation calculation software.

In steps 101 to 102, for each layer dislocation distance, positive and negative values are respectively taken for measurement, and the two obtained values are averaged as the corresponding measurement value of the layer dislocation distance. In order to reduce the measurement error and change the direction of the dislocation distance between layers, it can be realized by horizontally rotating the test platform on which the sample is placed by 180 degrees during the test.

After fitting the equation F corresponding to each wavelength, when measuring the layer dislocation distance, use any monochromatic polarized light in the FQ interval and the same incident angle in step 101 to enter the double-layer structure to be measured, and measure the zero-order diffracted light Focusing on the parameters, the layer dislocation spacing of the double-layer structure to be tested can be obtained. The parameter of interest can be the intensity of the zero-order diffracted light, or an ellipsometric parameter in ellipsometry, such as the magnitude Δ or argument Ψ of the ratio of the reflectivity of two different polarization states of incident light.

In the fitting process, first assume that the F2 (δ) equation is a continuity or discontinuity equation with a certain form. In the present invention, it is preferred to assume that the F2 (δ) equation is a continuous equation in the FQ interval. In step 102, for the fixed wavelength, After obtaining a point set including a plurality of corresponding zero-order diffracted light parameters-layer dislocation distances, the difference between the F equation and the point set is minimized by adjusting the undetermined coefficients in the F2(δ) equation. In general, the interlayer dislocation spacing δ is very small (on the order of several to tens of nanometers, much smaller than the wavelength of light), and the F2(δ) equation can be expressed as a linear function W=Pδ+a or a quadratic nonlinear function W= Qδ ² +Pδ+a, in order to reduce the amount of calculation. Where W is the zero-order diffracted light parameter, Q, P and a are undetermined coefficients, in the subsequent fitting process, according to multiple (W, δ) points, the fitting of P, a or Q, P, a specific value.

As shown in FIG. 1 , it is a double-layer structure forming an interlayer dislocation according to the present invention, and there is a one-dimensional periodic structure grating with the same shape between the two layers. The incident light is incident on the grating from the light source at a certain angle, and diffracted light is obtained. Diffraction light includes specular reflection light (that is, zero-order reflection light), non-specular reflection light (that is, +/-n-order reflection light, n>0), specular transmission light (that is, zero-order transmission light), and non-specular transmission light (i.e. +/- n levels of transmitted light, n>0). For the convenience of description, a three-dimensional Cartesian coordinate system is established in Figure 1. The x-axis is the extension direction of the periodic grating, which is perpendicular to the grating lines, the y-axis is parallel to the grating lines, and the z-axis is perpendicular to the surface of each layer. The periodic grating is parallel to the x-y plane.

Fig. 2 is a cross-sectional view of a two-layer one-dimensional periodic grating, and the dislocation size between layers of the grating is δ. In Figure 2, the upper and lower gratings define the first and second layers respectively, and the ratio of the width of the first material in each layer to the entire period is defined as the duty ratio, and the duty ratios of the first and second layers are: f ₁ , f ₂ . The thicknesses of the two gratings are d ₁ and d ₂ respectively. The periods of the two gratings are Λ, and the refractive index of the base material is n _s . According to the characteristics of these gratings, the parameters of the zero-order diffracted light are analyzed and calculated.

For clarity of description, it is stipulated that the upper layer is positively dislocated relative to the lower layer along the x-axis, that is, if δ is dislocated to the right in Figure 2, then δ is a positive value; if it is negative, it is dislocated along the left direction of the x-axis.

In the aforementioned steps 101 to 102, for each layer dislocation distance, positive and negative values are respectively taken for measurement, and the two obtained values are averaged as the corresponding measurement value of the layer dislocation distance. In order to reduce the measurement error and change the direction of the dislocation distance between the layers, it can be realized by horizontally rotating the test platform on which the sample is placed by 180 degrees during the test.

In step 101, when measuring the parameter of interest of the zeroth-order diffracted light, within a wavelength range of Δλ centered on the measured wavelength, the average value of the parameter of interest of the zero-order diffracted light is taken, where Δλ is the bandwidth of the incident monochromatic polarized light .

Fig. 3 shows the schematic diagram of the optical path principle of the measurement using the spectroscopic ellipsometer. The measuring device is composed of the spectroscopic ellipsometer and the data processor connected with the spectroscopic ellipsometer. The spectroscopic ellipsometer includes a light source 1 and a grating tunable filter. 7. Composed of a polarizer 2, a first rotational phase compensator 3, a second rotational phase compensator 4, a polarizer 5 and a receiving spectrometer 6.

As shown in Figure 3, the light from the light source 1 becomes monochromatic light of a single frequency after passing through the grating tunable filter, and becomes polarized light through the polarizer 2, and the first rotary phase compensator 3 is used to perform phase compensation on the polarized light to To obtain the required specific polarized light, the compensated monochromatic polarized light is incident on the surface of the double-layer structure, and on the diffraction path of the zero-order diffracted light, the second rotational phase compensator 4 adjusts the phase of the reflected light, and passes through the analyzer 5 1. The receiving spectrometer 6 detects, and indirectly measures the parameters Δ and ψ by detecting the light intensity at different angles.

Taking the double-layer periodic structure (grating) shown in FIG. 2 as an example, the dislocation size between layers of the grating is δ. In Figure 2, the lower dielectric of the grating is silicon dioxide (SiO2) grating lines and polysilicon (Poly-Si) spacers, and their duty ratio is 6:4, that is, the ratio of silicon dioxide grating lines to the periodic length is 60%, and the thickness is d ₂ =300 nm. The upper grating is made of air (Air) and polysilicon (Poly-Si), and their duty ratio is 6:4, that is, the ratio of the air part to the period length is 60%, and the thickness is d ₁ =500nm. The period Λ is 500 nm. The substrate layer dielectric is silicon (Si).

For the above structure, two embodiments are given:

Embodiment 1. The incident angle during measurement is θ=60 °, φ=90 °, as shown in Figure 1, θ is the angle between the incident direction and the vertical direction of the incident surface, and φ is the monochromatic diffracted light incident plane The angle between the extension direction and the grating periodic arrangement. The incident light incident on the surface of the bilayer structure is s-polarized. The interlayer dislocation spacing δ is respectively taken as -50, -40, -30, -20, -10, 0nm, and the spectrum whose amplitude varies with the wavelength of the incident light wave is calculated, and Figure 4 is obtained; the interlayer dislocation spacing δ is respectively taken as -50, -40, -30, -20, -10, 10, 20, 30, 40, 50nm, calculate the change spectrum of the argument angle with the incident wavelength to get Figure 5.

It can be seen from Fig. 4 that the amplitude is sensitive to the interlayer dislocation spacing δ in the wavelength range of 590–640 nm. Within this wavelength range, the amplitude values of different curves corresponding to the same wavelength vary greatly and more regularly. Therefore, when the parameter concerned is the amplitude, the above-mentioned 590-640 nanometers can be selected as the wavelength interval FQ. It can be seen from Fig. 5 that the argument angle is sensitive and regular to the change of the interlayer dislocation spacing δ in the wavelength range of 940-970 nanometers. Therefore, the above-mentioned 940-970 nanometers can be selected as the wavelength interval FQ when the parameter of interest is the argument.

In Example 1, when the parameter of interest is the amplitude, the wavelength curves corresponding to the interlayer dislocation distance -δ and +δ coincide in this embodiment (when δ=0, the amplitude is zero), which cannot characterize the interlayer dislocation direction. When the parameter of concern is the argument angle, the change of the wavelength curve at the interlayer dislocation distance δ→0 is not regular, but the phase difference between the wavelength curves corresponding to -δ and +δ is π, which can characterize the direction of interlayer dislocation.

After the wavelength interval is selected, the average value of the amplitude or argument corresponding to the same wavelength interval is extracted from each curve, and the F equation of the parameter concerned in the wavelength interval is fitted. According to the measured amplitude or argument during measurement, the layer dislocation spacing can be obtained according to the F equation.

The difference between embodiment 2 and embodiment 1 is that the incident angles during measurement are θ=45°, φ=45°. Figure 6 is obtained by measuring and calculating the spectrum whose amplitude varies with the wavelength of the incident light wave. It can be seen from Figure 6 that within the range of 560-580 nanometers, the amplitude values of different curves corresponding to the same wavelength vary greatly, so the frequency interval FQ can be selected as 560-580 nanometers.

From Embodiments 1 and 2 and Figures 4 to 6, it can be seen that when θ=45°, φ=45° incident angle is selected, the amplitude value is stable and not very sensitive to the change of angle θ, φ. However, from the perspective of practical operation, it is relatively difficult to select θ=45°, φ=45°, which is easy to realize in the specific measurement operation process, and when θ=60°, φ=90° are selected, due to the zero-order diffracted light Under this incident angle, the parameters are more sensitive to the change of interlayer dislocation spacing, so the interlayer dislocation δ value of the symmetrical periodic grating structure can be measured in a wider range.

The above describes the measurement of the stacking fault pitch in the one-dimensional direction. If the stacking fault pitch in the two-dimensional direction is to be measured, it is necessary to construct a two-dimensional periodic grating structure on both layers forming the stacking fault pitch. The specific implementation method is as follows: At the same position of each layer structure, two sets of one-dimensional gratings perpendicular to each other are made as marking lines. Using the method described above, the layer dislocation spacing of two one-dimensional grating marking lines perpendicular to each other is tested to obtain Interlayer misalignment of two-dimensional grating structures in two directions perpendicular to each other.

For example, a one-dimensional periodic grating in the X direction can be printed on the upper left corner of the laminate, and a one-dimensional periodic grating in the Y direction perpendicular to it can be printed on the upper right corner. The process of alignment can be realized in the x and y directions respectively, and the processing of multi-layer structure products can be guaranteed. During the measurement, the above-mentioned method of measuring the one-dimensional layer dislocation spacing is used to measure the interlayer dislocation in the x and y directions respectively, and the two one-dimensional layer dislocation spacings are tested, and the two-dimensional layer dislocation spacing in the two directions can be obtained. .

Using the interlayer dislocation test method for double-layer periodic microstructures of the present invention, by testing the relevant parameters of the light diffraction wave electric field in different polarization states, instead of the traditional test of light intensity, by testing different angles and different Spectrum test of parameters, select the most sensitive space angle and diffracted light parameters for interlayer misalignment, combined with simulation calculation and analysis of light diffracted wave electric field, to achieve high-precision interlayer misalignment test.

In the above measurement methods, the selection of the incident angle can better achieve greater sensitivity to achieve better measurement results; the average value of the positive and negative values of the layer dislocation distance is used as the measurement value to reduce the measurement error. When the interstitial dislocation distance is small, the F2(δ) equation can be assumed to be a linear equation or a quadratic equation for fitting to reduce the calculation intensity.

The steps of the methods or algorithms described in the embodiments disclosed in the present invention can be directly implemented by hardware, software modules executed by a processor, or a combination of both. Software modules can be placed in random access memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other Any other known storage medium.

The foregoing are various preferred embodiments of the present invention. If the preferred implementations in each preferred embodiment are not obviously self-contradictory or based on a certain preferred implementation, each preferred implementation can be used in any superposition and combination. The above examples and the specific parameters in the examples are only for clearly expressing the inventor's invention verification process, and are not used to limit the scope of patent protection of the present invention. The scope of patent protection of the present invention is still subject to its claims. The equivalent structural changes made in the specification and drawings of the present invention should be included in the protection scope of the present invention in the same way.

Claims (8)

1. the dislocation of the interlayer for a double-deck periodic micro structure method of testing, for testing the fault column pitch δ of double-layer grating structure, comprise fault column pitch-diffraction light equation F fit procedure, described fault column pitch-diffraction light equation model process comprises the steps:

Step 101. along certain angle double-decker surface incident to be measured, measures the concern parameter F of zero order diffracted light with the directional light of monochromatic polarization; Monochromatic polarized light frequency sweep exports, and obtains the wavelength curve of the concern parameter under fixed bed dislocation spacing δ;

Fault column pitch δ in the change step 101 of step 102. only equal difference, repeatedly repeats step 101, obtains one group of wavelength curve group F1 (λ, δ) by concern parameter F corresponding to the fault column pitch value δ of equal difference discrete series; Wherein λ is wavelength;

Step 103. is at curve group F1 (λ, select δ) to change with δ, pay close attention to the range of wavelengths FQ that Parameters variation is the most responsive, to the arbitrary fixed wave length be in FQ, the value of several concerns parameter F utilizing different layers dislocation spacing corresponding, simulates the function that the concern parameter under this wavelength changes with fault column pitch; Change wavelength and repeat matching, obtain the function F 2 (δ) that the concern parameter under each wavelength in FQ interval changes with fault column pitch, as fault column pitch-diffraction light equation F;

The described dislocation of the interlayer for double-deck periodic micro structure method of testing is after obtaining F2 (δ), when measuring fault column pitch, use the incident double-decker to be measured of incident angle that any monochromatic polarized light edge be in FQ interval is same with step 101, measure the concern parameter of zero order diffracted light, according to concern parameter value and the wavelength value of correspondence, double-deck fault column pitch to be measured can be drawn.

2. as claimed in claim 1 for the interlayer dislocation method of testing of double-deck periodic micro structure, it is characterized in that: described concern parameter is the ellipsometric parameter in ellipsometric measurement, namely plane of incidence tangentially with amplitude, ao and/or the argument Ψ of the ratio of the Zero-order diffractive optical electric field of normal direction two polarization directions.

3., as claimed in claim 1 for the interlayer dislocation method of testing of double-deck periodic micro structure, it is characterized in that: the incident direction of described monochromatic polarized light is: θ=φ=45 degree, or θ=60 degree, φ=90 degree;

θ is the angle between incident direction and the vertical direction of incidence surface, and φ is the angle that monochromatic diffraction light plane of incidence and grating periodic arrange between bearing of trend.

4. as claimed in claim 1 for the interlayer dislocation method of testing of double-deck periodic micro structure, it is characterized in that: in described step 101 to 102, to each fault column pitch, get positive and negative values respectively and measure, as the corresponding measured value of this fault column pitch after two values obtained are average.

5., as claimed in claim 1 for the interlayer dislocation method of testing of double-deck periodic micro structure, it is characterized in that: to suppose that F2 (δ) carries out matching for once linear or quadratic nonlinearity equation in described step 103.

6., as claimed in claim 1 for the interlayer dislocation method of testing of double-deck periodic micro structure, it is characterized in that:

In step 101, when measuring the concern parameter of zero order diffracted light, within the scope of the wavelength width of the △ λ being wavelengths centered with tested wavelength, average to the concern parameter of zero order diffracted light, wherein △ λ is the bandwidth of incident monochromatic polarized light.

7., as claimed in claim 1 for the interlayer dislocation method of testing of double-deck periodic micro structure, it is characterized in that: measurement mechanism is made up of spectroscopic ellipsometers and the data processor that is connected with spectroscopic ellipsometers.

8. the dislocation of the interlayer for a double-deck periodic micro structure method of testing, for testing the fault column pitch of two-dimension periodic grating, it is characterized in that: in the same position of every Rotating fields, all make orthogonal two groups of one-dimensional gratings as graticule, adopt as the method in claim 1 to 6 as described in any one, by testing out the fault column pitch of the one-dimensional grating graticule of two mutually perpendicular directions, obtain the interlayer dislocation of two-dimensional grating structure in orthogonal both direction.