CN1321316C - Optical measuring device and optical measuring method - Google Patents

Abstract

The invention discloses an optical meausring instrument and an optical measuring method to precisely measure a periodic array pattern of electrodes. When a glass substrate of a measuring object is irradiated with convergence light via a condenser lens 114, diffraction light generated by the array pattern of the electrodes 31 is generated to be reflected on a surface 3a and a reverse face 3b of the substrate. A one-dimensional CCD 122 is arranged in a position where surface reflected light and reverse face reflected light get incident under a condition near to a condensing condition. The respective reflected lights get incident separately into the CCD 122, and m-degree of the reverse face reflected light get incident between an incident position of m-degree of the surface reflected light and an incident position of (m+1) degree of the surface reflected light. Only the intensities of the surface reflected lights are extracted out of a photoreception quantity data obtained by the one-dimensional CCD 122, and the array pattern of the electrodes 31 is measured based on a distribution state thereof.

Description

Optical gauge and optical measuring method

Technical field

The substrate with light transmission that the present invention relates to works periodicity as the glass substrate of LCD (LCD) usefulness, prescribed level assortment is an object, measures the optical gauge of the cycle assortment figure of said structure thing.

In this manual,, be to be that example is illustrated with the electrode, but be not limited thereto as works, also can be with colored filter and black surrounded tube etc. as works.Can both measure size, shape, height and width etc. at any works.

Background technology

Have in the existing method of periodic convex-concave pattern in mensuration, by producing repeatedly diffraction light to convex-concave pattern irradiates light as object of observation, contrast by relation and theoretical value, measure the cycle of concave depth and width, assortment etc. the diffraction light intensity of each time.(with reference to patent documentation 1).

Patent documentation 1 is flat 9-5049 communique for the spy opens.

Above-mentioned prior art is being applicable under the situation of transparency carrier, except the diffraction light of substrate surface reflection (below be called " surface reflection "), also need to consider to see through substrate and the diffraction light of lateral reflection (below be called " back reflected light ") overleaf.Figure 17 illustrates the forward travel state with the light under the situation of the optical system mensuration transparency carrier of existing structure.3a among the figure is the upper surface of glass substrate 3, is formed with electrode 31 every the interval of regulation.In this instructions, with the surface of this upper surface 3a as glass substrate 3.In addition, with the face 3b of the inboard, bottom surface of glass substrate 3 as the back side.

Existing optical system by the light after the parallelizations such as collimation lens, on the other hand, disposes condenser 200 and one dimension CCD201 (following only be called " CCD201 ") to the determination object irradiation on from the catoptrical light path of glass substrate 3.In Figure 17, illustrate according to the irradiates light of glass substrate 3 (following only be called " substrate 3 ") and the light path of surface reflection with solid line, on the other hand, the light path that sees through light and back reflected light of transmission in substrate 3 is shown with dot-and-dash line.Under situation, also become parallel state from the reflected light of substrate 3 sides to substrate 3 irradiation parallel beam light.In addition, because back reflected light also becomes parallel relation with surface reflection, therefore, the reflected light that has passed through behind the condenser 200 can be focused on the certain location.Dispose above-mentioned CCD201 accordingly with this catoptrical spot position.

Have again, in above-mentioned Figure 17, only show the forward travel state of 0 diffraction light, but,, surface reflection and back reflected light are focused on the ad-hoc location of CCD201 also according to same principle about other diffraction lights.

In the example of this Figure 17, if the thickness of substrate 3 is greater than the coherent length of light source, then become the hands-off state of surface reflection and back reflected light, can both obtain being equivalent to light income the value after the intensity addition of surface reflection light intensity and back reflected light at any diffraction light.

Figure 18 A～Figure 18 C is used to illustrate above-mentioned research.Figure 18 A be hypothesis on the CCD201 only optically focused the distribution curve of the light income under the situation of surface reflection, Figure 18 B is the distribution curve of the light income under the situation of back reflected light of only having supposed optically focused.A plurality of peak values of the diffraction light intensity of each number of times have all appearred reflecting on these curves, but the coordinate unanimity of the peak value between curve.Figure 18 C has added the curve that obtains after the intensity shown in the curve of Figure 18 B in the shown intensity of the curve of above-mentioned Figure 18 A.According to the optical system of above-mentioned Figure 17, can think the distribution curve that has obtained this Figure 18 C.

Above-mentioned such mensuration processing generally is to be provided with under the state of glass substrate to carry out on the brace table that is known as " deciding plate " (having cast iron to decide plate and Shi Ding plate etc.).But, if substrate, then because following former thereby be difficult to correctly obtain the backside reflection light intensity at such state lower support.

At first, first is because the upper surface of deciding plate is not a surface level completely, therefore, as shown in figure 19, is deciding to produce air layer sometimes between plate (illustrating with Reference numeral 400 among the figure) and the substrate 3.The reflectivity at the back side of glass substrate 3 just with the situation of deciding plate 400 contact with situation that air contact in different, therefore, the backside reflection light intensity is just because of the position difference of reflection.In addition, as with dashed lines arrow q among the figure ₁, q ₂Shown in, when the light that sees through from substrate 3 in air layer during multipath reflection, its reflected light might exert an influence to the backside reflection light intensity.

In addition, decide in the plate at stone, use the stone of black more in order to reduce reflected light, but owing to the irregular colour of the stone that becomes material is even, sneak into the stone that turns white sometimes, therefore, the reflectivity of deciding plate just can not be certain.Decide plate about cast iron, the painted black in order to reduce reflected light equally, but if coating color inequality sometimes then can not make reflectivity certain equally.The deviation of the reflectivity of deciding plate so also becomes the reasons of error that increases the backside reflection light intensity.

Because aforesaid former thereby can not correctly obtain under the situation of backside reflection light intensity, just be difficult to be reflected accurately the distribution of reflected light curve of the shape of electrode pattern, just there is error at measurment to become big problem.

Summary of the invention

The present invention is the starting point with this problem, and its purpose is to provide a kind of optical gauge and optical measuring method, by separately take out the surface reflection of substrate from back reflected light, carries out the mensuration to the cycle assortment figure of works accurately.

The optical gauge that the present invention relates to, to have on the substrate of light transmission works with the periodicity assortment as determination object, the diffraction light that has produced when having used a plurality of periodic works irradiates light to institute's assortment of above-mentioned substrate surface is measured the said structure thing.This device has: light-projecting portion, it is comprising the light that focuses on along the direction of the assortment direction of said structure thing with in the cross section of the face of the direction of the optical axis of the light of the surface irradiation of aforesaid substrate by oblique incidence to the surface irradiation of substrate, thereby with respect to the surface of aforesaid substrate, above-mentioned cross section becomes the plane of incidence;

Light accepting part, it includes imaging apparatus, described imaging apparatus has a plurality of light pixels that are subjected to of institute's assortment, and the direction of this assortment is the direction that is comprised by in the face of determining along the direction of the direction of the assortment direction of said structure thing and the optical axis by the light after the surperficial normal reflection of aforesaid substrate

On above-mentioned imaging apparatus, determine above-mentioned light-projecting portion with respect to the irradiating angle of the distance of aforesaid substrate and irradiates light, include distance and the angle of the light accepting part of above-mentioned imaging apparatus with respect to aforesaid substrate, make that m time diffraction light of back reflected light incides m time diffraction light of the surface reflection that is produced by above-mentioned irradiates light and (m+1) between the position of inferior diffraction light incident (m is an integer arbitrarily, in the diffraction light that on aforesaid substrate, reflects, will just be made as) away from a side of light-projecting portion.

The described plane of incidence is meant by with respect to as the normal of the substrate of determination object with towards the plane of the direction defined of the light of substrate irradiation.

In above-mentioned optical gauge, the works on the transparency carrier as glass substrate, can will can see through the works that forms on the translucent substrate of light as determination object.The surface of so-called substrate can think assortment works have a concavo-convex face.Can think that in addition the back side is the face of inboard of the bottom surface of substrate.Light-projecting portion preferably includes the such light source of laser diode and a plurality of lens, constitutes to shine point-like light or the banded light that comprises with a plurality of works of periodicity assortment.

For surface irradiation focused light, be preferably in the lens group of above-mentioned light-projecting portion and have condenser to aforesaid substrate.On the other hand, also condenser can be set in the light accepting part side.In addition, imaging apparatus also can use along with the one dimension imaging apparatus and the two-dimentional imaging apparatus of the reflected light of each diffraction light direction arranged side by side configuration.As the example of imaging apparatus, comprise CCD and cmos device, photodiode array.

As the condenser of light-projecting portion side, if use focal length to be far longer than the lens of the distance of these lens and substrate, even the light of Ju Jiaoing then also can shine the light of the size of a plurality of works of crosscut.The diffraction light that is produced by this irradiates light reflects at the surface and the back side of substrate, but also keeps focus state after the reflection, and optically focused is on the position of regulation.In addition, therefore back reflected light, can make its optically focused on the position different with surface reflection in the reflection in the localities of specific surface reflected light away from light-projecting portion.

Leaving from substrate under the situation that predetermined distance is provided with condenser, preferably aiming at and think that measuring the position that required surface reflection carries out optically focused disposes above-mentioned imaging apparatus.Under this situation,, estimate that spot position has some changes, but, just can inject the light that fully draws on the imaging apparatus if increase the depth of focus of condenser according to the size and the cycle of works.Consider the front of the spot position of back reflected light in addition, but can similarly inject the light of the state of abundant gathering at imaging apparatus.About surface reflection and back reflected light, can both make it on imaging apparatus, form the picture of abundant distinctness.

In addition, since with above-mentioned imaging apparatus be configured to m time back reflected light incide m time surface reflection incoming position and (m+1) between the incoming position of inferior surface reflection, therefore, as the distribution curve of light income, the picture that can access surface reflection and the picture of back reflected light are alternately and the curve of the state that is arranged in order by number of times.Like this,, just can obtain the surface reflection light intensity of each number of times,, can measure the size of works and the cycle of assortment etc. based on this intensity by selecting a peak value in this distribution curve.

The positive direction of m be with in the diffraction light that on substrate, reflects from a light-projecting portion side far away for just, if do not use lens, then also be for just on imaging apparatus from a light-projecting portion side far away at light accepting part.On the other hand, be provided with in light accepting part under the situation of sensitive lens, the distally just becomes negative, and nearside just becomes.

The optical gauge of preferred forms is provided with extraction element and determinator, described extraction element based in the light income that obtains by above-mentioned imaging apparatus, concern with the position of the maximal value in the distributed data of the assortment direction of pixel and above-mentioned light-projecting portion and light accepting part about the above-mentioned light that is subjected to, from the distributed data of above-mentioned light income, individually extract the surface reflection light intensity of each number of times, described determinator uses each the surface reflection light intensity that is extracted by the said extracted device, measures the said structure thing.

This embodiment go for as the matrix assortment of LCD with substrate the figure of structure of rectangular configuration thing be the situation of determination object.Under the situation of the convex-concave pattern that has produced rectangle owing to such matrix assortment on the surface at substrate, following 0 the diffraction light intensity of more situation has overwhelming advantage.Can think that the reflected light of 0 diffraction light of such situation and surface reflection and backside reflection are jointly than the reflective light intensity of other diffraction lights.

In addition, according to above-mentioned optical system, in the distribution curve of light income, owing to alternately and by number of times be arranged in order with the corresponding peak value of surface reflection with the corresponding peak value of back reflected light, therefore, can think that wherein largest peaks and second largest peak value part arranged side by side is corresponding with 0 diffraction light.In addition, because surface reflection produces than the place of backside reflection at more close light-projecting portion, therefore, can think that the picture of surface reflection is created on than on the close position of light-projecting portion of the picture of back reflected light.

By carrying out digital conversion, can access the distributed data of light income from the light income signal of imaging apparatus.Can constitute said extracted device and determinator by the computing machine of the distributed data of handling this light income.Extraction element is based on above-mentioned principle, and the second largest peak value that extracts maximal value and be adjacent from the peak value shown in the distributed data of light income extracts the peak value approaching with light-projecting portion wherein, as with the corresponding peak value of the surface reflection of 0 diffraction light.In addition, with the corresponding peak value of the surface reflection of this 0 diffraction light be benchmark, extract a peak value, just can extract the corresponding peak value of surface reflection with the diffraction light of number of times except 0 time.Like this, the shown value of peak value that just can specific each number of times extracted is as the surface reflection light intensity of this number of times.Have, the surface reflection light intensity is not limited only to peak value again, and also can be made as integration is value after the data of specialized range at center with the peak value.

The distribution curve of the intensity of each number of times that the said determination device will extract is compared with pre-prepd a plurality of theoretical curves, can measure height, width of works etc.Have again, suppose that height, width and the cycle of works is setting,, just can access theoretical curve by obtaining the surface reflection light intensity of diffraction light.In addition, be preferably in the parameter that is used for deriving curve separately (cycle of the height of above-mentioned works, width, assortment etc.) and set up corresponding state, each theoretical curve is logined in the storer of the computing machine of having set said extracted device and determinator.

Determinator can utilize for example least square method at the distribution curve of the intensity of said extracted, extracts and the immediate theoretical curve of this distribution curve, and specific and the shown assortment figure of this theoretical curve corresponding parameter are as the structure of determination object.Like this, just can export the value shown in the parameter of specific assortment figure, as measurement result.

The optical gauge that comprises more preferably embodiment in the above-described embodiment has input media and calculating apparatus, the assortment cycle of the works of described input media input determination object, described calculating apparatus uses the assortment cycle by above-mentioned input media input, calculates the interval of incoming position of the surface reflection of each number of times in the above-mentioned one dimension imaging apparatus.Maximum and second largest peak value part arranged side by side in extraction element under this situation distributed data from the light income that obtains by above-mentioned imaging apparatus, relevant with the above-mentioned assortment direction that is subjected to light to use pixel, the a side corresponding peak value approaching in the specific diffraction light that on aforesaid substrate, reflects with light-projecting portion, incoming position as 0 time surface reflection, simultaneously, specificly left the m position of the distance of (wherein m ≠ 0) doubly that is equivalent to the interval that calculates by above-mentioned calculating apparatus, as the incoming position of m time surface reflection from this incoming position.Then, based on these certain location, extract each surface reflection light intensity.

In above-mentioned, input media can constitute the input channel that the data in assortment cycle are shown from input part such as keyboard or external unit input.Can become calculating apparatus by the calculation mechanism identical with determinator with the said extracted device.This calculating apparatus can arrive the distance L of imaging apparatus, light wavelength, incident angle and the above-mentioned assortment cycle of light-projecting portion based on 0 time surface reflection, obtain the incoming position of m time surface reflection on the imaging apparatus and (m+1) inferior surface reflection incoming position apart from a.Can think that this is equivalent to the interval of incoming position of the surface reflection of above-mentioned each number of times apart from a.

Have again,, can obtain above-mentioned distance L in advance as the condition of the position that is used to adjust above-mentioned light accepting part.

The extraction element of this embodiment is also based on aforesaid principle, maximal value from the distributed data of light income and second largest peak value part arranged side by side, the a side corresponding peak value approaching in the specific diffraction light that on aforesaid substrate, reflects with light-projecting portion, as with the corresponding peak value of surface reflection, can be with the coordinate of this peak value incoming position as 0 time surface reflection.In addition, be benchmark by incoming position with this surface reflection of 0 time, the value that changes m is obtained the position of leaving (axm) to positive and negative two directions, incoming position that just can specific a plurality of surface reflections except 0 time.But this extraction is handled and is carried out in the length range of imaging apparatus, and the extraction number of positive dirction is not necessarily consistent with the extraction number of negative direction.

Like this, when the incoming position of the surface reflection of specific a plurality of number of times, extraction element just can be to each of this a few incoming positions, and integration is the specialized range at center etc. with this position, extracts each surface reflection light intensity.

Have again, above-mentioned two embodiments are that to have overwhelming dominance with 0 diffraction light than other diffraction lights be prerequisite, but with shape according to works, even with the periodicity assortment, it is corresponding that 0 diffraction light does not become maximum situation yet, about to the reflected light that produces from light time of light-projecting portion with the substrate irradiation of the same race of the determination object of assortment works not, it is specular light, obtain the scope of the incoming position in the imaging apparatus in advance, login is in storer, during mensuration, extract the largest peaks and second largest peak value from the light income of the scope of the above-mentioned login of imaging apparatus, specific their as and 0 corresponding peak value of diffraction light.

Suppose reflecting surface on the surface of the substrate of determination object between the back side, can obtain theoretically from the position of the reflected light incident of the substrate of assortment works not.Under this situation, the incoming position that can set has theoretically left scope than the position of the above-mentioned predetermined distance c little apart from a to positive and negative two directions, with it as the scope of above-mentioned incoming position and login.

About to the reflected light that produces from light time of light-projecting portion with the substrate irradiation of the same race of the determination object of assortment works not, be specular light, also can login the incoming position in the imaging apparatus in advance, utilize this incoming position or similarly carry out specific with the immediate peak value in this position.

In the optical gauge that the present invention relates to, can be provided with: position regulator, it is used to adjust the position with respect to the light-projecting portion of the direction vertical with the assortment direction of said structure thing; Control device, it uses the distributed data of the light income that is obtained by above-mentioned imaging apparatus, the position adjustment process that control is undertaken by above-mentioned position regulator.Position regulator under this situation can constitute the driving mechanism that a certain side that makes substrate or light-projecting portion moves.Particularly under the situation that substrate-side is moved, device for moving and adjusting can constitute the XY objective table of supporting substrates.

Control device can be by constituting with the same computing machine of said extracted device and determinator, can comprise following apparatus: when making above-mentioned position regulator carry out position adjustment process, extract not the device of the light income of the scope corresponding from the distributed data of the light income that under this state, obtains with back reflected light two sides of 0 time surface reflection and 0 time at every turn; The device that above extracted light income is compared with specified reference value; Use the result of above-mentioned comparison process, differentiate the device of the position relation that is suitable for measuring at aforesaid substrate and light-projecting portion.

Will be with the matrix assortment under the situation of substrate as determination object of rectangular configuration thing, with a certain side of the works of all directions as determination object (can be determination object successively with all directions also certainly).Under this situation, the diffraction light of the works generation of said determination object is input on the imaging apparatus, needs the assortment of this works of irradiation crosscut, and do not relate to the light of the opposing party's's (not being determination object) works.In addition,, just be difficult to produce diffraction of light, can think that only 0 time reflected light has advantage if the works outside determination object has shone light.According to above-mentioned embodiment, in the position of adjusting with respect to the light-projecting portion of the direction vertical with the assortment of the works of determination object, the light income of inspection except 0 time reflected light surpasses the position of reference value, and the position relation that just can be adjusted to the works of light-projecting portion and determination object becomes the state that is suitable for measuring.In addition, also can executing location adjustment processing, the extraction processing and the predefined number of times of comparison process of light income, the substrate when the extraction value of judging light income becomes with the immediate state of reference value concerns it is optimum condition with the position of light-projecting portion.Like this, by measuring processing behind the position of having adjusted substrate and light-projecting portion, just can increase substantially and measure the precision of handling.

Have again, in the above-described embodiment, in the extraction of light income is handled, also can be from the distributed data of the light income that obtains by imaging apparatus or the distributed data in the above-mentioned registered scope, judge that the part arranged side by side of largest peaks and second largest peak value is corresponding with 0 time diffraction light.Like this, can from except with this 0 corresponding part of diffraction light scope a part or all extract light income, compare with the said reference value.Also can extract reference value in advance, also can be set at the value that derives from theoretical value by the mensuration of the substrate that has used sample.In any case all preferably with in the storer of reference value login in device.

In addition, the assay method that the present invention relates to will have on the substrate of light transmission works with the periodicity assortment as determination object, and the diffraction light that produces when receiving a plurality of periodic works irradiates light to institute's assortment of this substrate surface is characterized in that,

Is radiated at by oblique incidence and comprises the light that focuses on along the direction of the assortment direction of said structure thing with in the cross section of the face of the direction of the optical axis of the light of the surface irradiation of aforesaid substrate, thereby with respect to the surface of aforesaid substrate, above-mentioned cross section becomes the plane of incidence,

Dispose imaging apparatus, described imaging apparatus has a plurality of light pixels that are subjected to of institute's assortment, the direction of this assortment is the direction that is comprised by in the face of determining along the direction of the direction of the assortment direction of said structure thing and the optical axis by the light after the surperficial normal reflection of aforesaid substrate, make m time diffraction light of back reflected light incide the diffraction light that produces by above-mentioned irradiates light surface reflection m time diffraction light and (m+1) between the position of inferior diffraction light incident (m is an integer arbitrarily, in the diffraction light that on aforesaid substrate, reflects, to just be made as away from a side of light-projecting portion), thus reception is with respect to the reflected light from substrate of above-mentioned irradiates light.

In the preferred forms that above-mentioned optical measuring method relates to, after above-mentioned imaging apparatus reception reflected light, based on the maximal value in the distributed data of the light income that obtains with towards the position relation of light-projecting portion with the light accepting part that includes above-mentioned imaging apparatus of the surface irradiation light of aforesaid substrate, from the distributed data of above-mentioned light income, individually extract the surface reflection light intensity of each number of times, use each the surface reflection light intensity that is extracted, measure the said structure thing.

In addition, in the optical measuring method that other preferred forms relate to, carry out making irradiation position with respect to the light of said structure thing when the direction vertical with the assortment direction of works moves repeatedly, use the distributed data of the light income that obtains by imaging apparatus to differentiate the step whether above-mentioned irradiation position is the position that is suitable for measuring.In the step of this differentiation, carry out: the step of extracting not the light income of the scope corresponding from the distributed data of the light income that obtains by above-mentioned imaging apparatus with back reflected light two sides of 0 time surface reflection and 0 time; The step that above extracted light income is compared with specified reference value when having obtained surpassing the light income of said reference value, is differentiated for the irradiation position at the light in this moment and is suitable for mensuration.。

According to the present invention, because the picture that can utilize picture that imaging apparatus obtains surface reflection and back reflected light alternately and the distribution curve of the light income of the state that is arranged in order by number of times, therefore, can from the distribution curve of this light income, extract the surface reflection light intensity of each number of times and measure.Like this, can not comprised the influence of the back reflected light of a lot of noise contributions, carry out high-precision mensuration and handle.

Description of drawings

Fig. 1 is the view that the outward appearance of optical gauge of the present invention is shown and makes use-case.

Fig. 2 is the block scheme that the electrical structure of optical gauge is shown.

Fig. 3 shows the structure of glass substrate, the parameter of determination object and the view of assay method.

Fig. 4 shows the primary structure of light-projecting portion and light accepting part and the view of effect.

Fig. 5 is the view that irradiates light and catoptrical forward travel state are shown.

Fig. 6 A～Fig. 6 C is the view that the best distribution relation of surface reflection and back reflected light is shown.

Fig. 7 is the view that the distribution curve conditions needed that obtains Fig. 6 is shown.

Fig. 8 A, Fig. 8 B utilize catoptrical light path to show a of Fig. 7, the view of b.

Fig. 9 is the view that the related definition of the width w of surface reflection light image is shown.

Figure 10 illustrates the process flow diagram that the surface reflection light intensity detects the order of processing.

Figure 11 is the view that the measuring method of intensity is shown.

Figure 12 illustrates the process flow diagram of measuring the order of handling.

Figure 13 is the view that illustrates at the good example of the irradiation position of banded light contrast and non-good example.

Figure 14 is the view of structure example that the testing fixture of electrode inspection usefulness is shown.

Figure 15 is that explanation is used for and will checks the view of processing of the light interception data of subject area and banded light contraposition.

Figure 16 is the process flow diagram that the order of inspection is shown.

Figure 17 is the view that the forward travel state of the structure of optical system of existing assay method and light is shown.

Figure 18 A～Figure 18 C is the view that the distribution relation of surface reflection that the optical system by Figure 17 obtains and back reflected light is shown.

Figure 19 is the view of problem points that the optical system of Figure 17 is shown.

Embodiment

Fig. 1 show one embodiment of the invention optical gauge outward appearance with make use-case.

This optical gauge is used for to being formed on its size of determination of electrode on the glass substrate 3 that LCD uses and the cycle of assortment etc., by cable 4 connection sensing head 1 and controllers 2.Have, controller 2 is interface board and programs that sensing head 1 usefulness has been installed in personal computer, comprises peripheral equipments such as keyboard 2a and monitor 2b again.

Comprise with the laser diode in the above-mentioned sensing head 1 is the light-projecting portion of light source and the light accepting part with one dimension CCD (following only be called " CCD ") etc.Controller 2 is taken into the output from CCD in the action of this sensing head 1 of control, carry out mensuration described later and handle.

Fig. 2 illustrates the electrical structure of above-mentioned optical gauge.Except light-projecting portion 11 and light accepting part 12, also comprise light projector circuit 13, light receiving circuit 14, timing control circuit 15 etc. in the above-mentioned sensing head 1.Have again, about the structure of light-projecting portion 11 and light accepting part 12, use Fig. 4 to describe in the back, but in light-projecting portion 11, have laser diode 111 (shown in Fig. 4), in light accepting part 12, have CCD122 (shown in Fig. 4).

Controller 2 the general structure, also has the interface board 20 of above-mentioned special use in having personal computers such as CPU21, storer 22, hard disk 23, input and output portion 24.On interface board 20, loading interface portion 25, A/D change-over circuit 26, sensor control circuit 27, triggering input part 28, power circuit 29 etc., be connected with cpu bus 201 by interface portion 25.

In above-mentioned, to be used to carry out in hard disk 23 stored of controller 2 and measure the program handled and decision table etc.Storer 22 is used for temporary transient the preservation and measures the light income table that uses.Input and output portion 24 comprises keyboard 2a, monitor 2b, to the lead-out terminal of not shown external unit output etc.

The sensor control circuit 27 of interface board 20 is used for the timing control circuit 15 of sensing head 1 is informed the trigger pip of measuring the timing of handling.This trigger pip is except can be based on, also can generating based on the instruction from CPU21 generating from the external signal that triggers input part 28.Can set by prior data input and adopt which kind of trigger pip.Have, the sensor etc. that triggers input part 28 and substrate detection usefulness is connected again.

Timing control circuit 15 outputs to it in light projector circuit 13 and the light receiving circuit 14 according to the timing signal of above-mentioned trigger pip generation specified length.Light projector circuit 13 drives the laser diode 111 of light-projecting portion 11 based on this timing signal.Light receiving circuit 14 drives the CCD122 of light accepting part 12 based on above-mentioned timing signal.Like this, just can be according to accepting reflected light from glass substrate 3 with the luminous synchronous timing of laser diode 111.

To be input to laggard line number word conversion in the A/D change-over circuit 26 of interface board 20 by the light income signal that CCD122 generates.CPU21 is taken into the digital signal (below be called " light interception data ") of this light income signal by interface portion 25, be stored in the storer 22 after, use the light interception data in this storer 22, carries out above-mentioned mensuration processing.

Have, above-mentioned power circuit 29 is used for to sensing head 1 supply power again.Though not shown among Fig. 2, from the power lead of this power circuit 29, from the transmission line of the trigger pip of sensor control circuit 27, from transmission line of the light income signal of CCD122 etc., all be contained in the above-mentioned cable 4.

Fig. 3 illustrates the side and the upper surface of above-mentioned glass substrate 3 enlargedly.This glass substrate 3 (following only be called " substrate 3 ") has the thickness t of regulation, on upper surface 3a, along all directions in length and breadth, disposes the rectangular shape electrode 31 of a Rack respectively at regular intervals.In this embodiment, be the starting point (certainly, also can be successively be the starting point with the cycle assortment of all directions) with the cycle assortment of the electrode 31 in the some directions in the both direction, along the banded light 5 of its assortment direction irradiation specified length.Like this, a plurality of diffraction lights of the concavo-convex state of reflection electrode 31 have just been produced, in the surface and the backside reflection of substrate.The surface of described substrate 3 the has been equivalent to assortment upper surface 3a of above-mentioned electrode 31 is arranged again.In addition, the face 3b of inboard, bottom surface can be thought in the back side of so-called substrate 3.In addition, the bottom surface of substrate 3 is supported in not shown deciding on the plate.

In Fig. 3, h illustrates the height of electrode 31, and d illustrates the width of electrode 31, and Λ illustrates the assortment cycle of electrode 31.In this embodiment, the thickness t and the periods lambda of substrate 3 are certain, with the value of h, d as determination object.In order to carry out this mensuration, in this embodiment,, obtain the theoretic intensity of the surface reflection of each diffraction light in advance about the different a plurality of cycle assortment figure of the combination of above-mentioned h, d value, login is in above-mentioned storer 22.Specifically, logined each diffraction light intensity and the corresponding decision table of each assortment figure foundation.CPU21 uses the light interception data that obtains from the substrate 3 of process object, measures the surface reflection light intensity that relates to each number of times, by this measured value and above-mentioned decision table are contrasted, comes the h of specific aforesaid substrate 3, the value of d.Narrate in detail about this processing later on.

Fig. 4 shows light-projecting portion 11 and the primary structure of light accepting part 12 and their effect in the above-mentioned sensing head 1.Have, x, y are to be the coordinate axis of benchmark with the assortment as the electrode of determination object among the figure again, and y is corresponding to the assortment direction of electrode, and x is corresponding to the direction vertical with the assortment direction of electrode.In addition, the frame (A) of drawing among the figure illustrates state to substrate 3 irradiates lights, draws state from frame (B) to CCD122 focus reflection light is shown.

Above-mentioned light-projecting portion 11 is to have disposed collimation lens 112, cylindrical lens 113 and condenser 114 successively in the place ahead of the laser diode 111 that becomes light source to form.On the other hand, the structure of light accepting part 12 is to have disposed cylindrical lens 121 in the place ahead of above-mentioned CCD122.Have, the laser diode 111 of light-projecting portion 11 sides and each lens 112,113,114 are supported by the retainer 115,116,117,118 of special use respectively again.Equally, the lens 121 of light accepting part 12 sides and CCD122 are also being supported by the retainer 123,124 of special use.

In above-mentioned, the light that penetrates from laser diode 111 by after the parallelization, passes through cylindrical lens 113 and condenser 114 by collimation lens 112 successively.Cylindrical lens 113 draws the directional light that has passed through above-mentioned collimation lens 112 on the x direction, generate long banded light on the y direction.The directional light that constitutes this band shape light is transformed into focused light by condenser 114.But, because condenser 114 uses focal lengths to be far longer than the lens of these lens 114 to the gauged distance of substrate 3, therefore, as draw shown in the frame (A), can be to the banded light 5 of the length of the electrode 31 of substrate 3 irradiation crosscut specified quantities.

The CCD122 of light accepting part 12 sides is configured in the corresponding position of the focal length of this condenser 114, promptly can cut for the reflected light of the diffraction light of above-mentioned banded light 5 and be subjected on the position of light (being described in detail later on).Have again, because the effect of the cylindrical lens 113 of light-projecting portion 11 sides, each reflected light becomes at the light of widening in the opposite direction with the gathering side of above-mentioned light-projecting portion 12 sides, this is widened but the cylindrical lens 121 of light accepting part 12 sides has gathering, above-mentioned reflected light is configured as the function of the banded light 6 of specified length.

Have again, in this embodiment, adjusted the curvature of cylindrical lens 121, make banded light 6 longer than the width of the pixel 122a of CCD122.In addition, configuration CCD122, make its pixel assortment and banded light 6 also column direction is corresponding.In drawing frame (B), the pixel assortment direction of CCD122 as Y, is illustrated perpendicular direction as X.

Show to Fig. 5 pattern the forward travel state of the light in the optical system of above-mentioned Fig. 4.In this Fig. 5, illustrate according to irradiates light and surface reflection with solid line to substrate 3, illustrate according to transmitted light and back reflected light with dot-and-dash line to substrate 3.Have again, in this Fig. 5,, only show the related light path of diffraction light 0 time, but, also can access same relation about other diffraction lights for the relation of clear and definite each surface reflection and back reflected light.

By condenser 114, after the directional light that will generate in above-mentioned light-projecting portion 11 converts focused light to, shine to substrate 3.Substrate 3 is minute surfaces, so surface reflection is also kept focus state, at assigned position optically focused.Back reflected light is kept the state of bringing together too, but this back reflected light is with respect to the farther reflection in the localities of light-projecting portion 11 specific surface reflected light, so optically focused is being different from the position of surface reflection.

Have, as if being the starting point with corresponding surface reflection of 1 light path and back reflected light with irradiates light, then these reflected light just become the parallel light that advances above substrate 3 again.

In this embodiment, the height d of above-mentioned electrode 31 and width w are respectively settings, and the spot position of the surface reflection when having placed above-mentioned condenser 114 distance from substrate 3 to above-mentioned standard to being located at has disposed CCD122.In addition, if the assortment figure of electrode 31 and the height and position of sensing head 1 have change, just think that the spot position with respect to the surface reflection of CCD112 also changes, in addition, back reflected light is compared with surface reflection, because the distance from condenser 114 to reflection position is elongated, therefore, if as mentioned above the spot position that is positioned at surface reflection is disposed CCD122, then, still, increase as if the depth of focus that makes condenser 114 at the front of CCD122 optically focused, the deviation of these spot positions is just very little, and whole reflected light can both be injected among the CCD112 under the state that can regard spot condition as.Like this, behind release surface reflected light and back reflected light on the CCD122, it is injected, just can access the picture of each catoptrical distinctness.

Fig. 6 A～Fig. 6 C illustrates under the situation of having adjusted optical system as illustrated in fig. 5, the expectation state of the intensity distributions of the light income that is obtained by each pixel of CCD122.Fig. 6 A supposes the only distribution curve of surface reflection optically focused under the situation on the CCD122, has occurred the image with the corresponding mountain of the surface reflection of each number of times shape in accordance with regulations at interval.Below, the image of this mountain shape is called " surface reflection light image ".Fig. 6 B is the distribution curve under the situation of back reflected light of only having supposed optically focused, and is same, occurred the image with the corresponding mountain of the back reflected light of each number of times shape in accordance with regulations at interval.Below, the image of this mountain shape is called " backside reflection light image ".Fig. 6 C has added the intensity shown in the distribution curve of Fig. 6 B and the curve that obtains on the intensity shown in the distribution curve of above-mentioned Fig. 6 A.In the thickness t of substrate 3 coherent length, under the hands-off situation of surface reflection and back reflected light, obtain the distribution curve of the light income shown in this Fig. 6 C greater than light source.

Have, above-mentioned whole curves all are the coordinates that transverse axis is represented light interception data again, therefore, and corresponding to the Y direction of drawing frame (B) of above-mentioned Fig. 4.Dispose under the situation of light-projecting portion 11 and light accepting part 12 in the relation according to above-mentioned Fig. 4, in Fig. 6, advance to the direction of leaving light-projecting portion 11 more, coordinate is just big more.

The reflected light of each diffraction light based on the principle optically focused shown in above-mentioned Fig. 5 under the situation on the CCD122, shown in the example of this Fig. 6, the surface reflection light image P of m time diffraction light _mWith backside reflection light image p _mJust appear on the different positions.In addition, in the example of this Fig. 6, m time backside reflection light image p _mBe positioned at m time surface reflection light image P _mWith ensuing (m+1) inferior surface reflection light image P _M+1Between.In other words, become each surface reflection and back reflected light alternately and by the state of number of times gradate.

In addition, if to the convex-concave pattern irradiates light of the works of the such rectangular shape of the cycle graph of above-mentioned electrode, then in most cases 0 diffraction light has overwhelming dominance than other diffraction lights.Can think the surface reflection light image P of peak value maximum in the example of Fig. 6 A ₀Backside reflection light image p with peak value maximum in the example of Fig. 6 B ₀Corresponding with 0 diffraction light respectively.Shown in Fig. 6 C, can think that these reflected light are as P ₀, p ₀Adjacent in the distribution curve of the actual light income that obtains.Have again, among the figure, the picture P on 0 right side ₁, p1, P ₂, p ₂, P3, p ₃It is 1 time, 2 times, 3 times ... surface reflection light image and backside reflection light image, 0 left side the picture P _-1, p _-1, P _-2, p _-2, P _-3, p _-3It is-1 time ,-2 times ,-3 times ... surface reflection light image and backside reflection light image.

In the optical gauge that this embodiment relates to, the surface reflection of obtaining each diffraction light in advance separates the condition of optically focused afterwards with back reflected light on CCD122 under the state of above-mentioned Fig. 6 C, based on this condition, adjust the focal length of condenser 114 and the position relation of condenser 114 and CCD122 etc.Below use Fig. 7～Fig. 9, describe about this condition.

At first, Fig. 7 illustrates and is used for shown in Fig. 6 C like that alternately and by the related surface reflection light image of each number of times of gradate of number of times and the condition of backside reflection light image.Among the figure, P _m, P _M+1Be respectively m time, (m+1) inferior surface reflection light image, p _m, p _M+1Be m time, (m+1) inferior backside reflection light image.In order to obtain the distribution curve of the light income shown in above-mentioned Fig. 6 C, just need make the surface reflection light image P of same number _mWith backside reflection light image p _mDistance b less than surface reflection light image P _m, P _M+1Apart from a.That is the relation that, needs a＞b.

Fig. 8 A utilize above-mentioned m time and (m+1) light path of inferior surface reflection show above-mentioned apart from a.L among the figure is being adjusted into 0 time surface reflection optically focused producing in the length of the catoptrical light path of 0 subsurface under the situation on the CCD122 on the rayed position C to substrate 3.Below this L is called distance L.In this embodiment, utilize distance L to show and adjust above-mentioned optical system conditions needed.

Among the figure, θ _mIt is m time angle of diffraction.At this, if the cycle of the wiring graph of electrode is made as Λ, will shines light wavelength and be made as λ, the thickness of substrate is made as t, the incident angle of light is made as θ i, then diffraction angle _mCan obtain by following (1) formula.

$\mathrm{\θm}=m\·\frac{\mathrm{\λ}}{\mathrm{\Λ}\cos \mathrm{\θi}}---\left(1\right)$

θ _M+1Be (m+1) inferior angle of diffraction, can be replaced as (m+1) by m and obtain above-mentioned (1) formula.At this, if consider diffraction angle _m, θ _M+1Minimum (θ _m, θ _M+1＜＜1), then above-mentionedly just becomes the value approximate with the value of following (2) formula apart from a.

$a=L\·\frac{\mathrm{\λ}}{\mathrm{\Λ}\cos \mathrm{\θi}}---\left(2\right)$

Then, Fig. 8 B utilizes above-mentioned m time the surface reflection of diffraction light and the light path of back reflected light to show distance b.Angle θ among the figure _TrBe with respect to the vertical direction angulation through the diffraction light behind the substrate 3.In diffraction angle _mUnder the minimum situation, above-mentioned distance b is similar to the value of following (3) formula.Have again, in (3) formula, n ₂It is the refractive index of substrate back.

$b=2t\&CenterDot;\tan \mathrm{\&theta;tr}\&CenterDot;\cos \mathrm{\&theta;i}=2t\&CenterDot;\tan \&lsqb;{\sin }^{-1}\&lsqb;\frac{\sin \mathrm{\&theta;i}}{{\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="C20051000833700271.png,C20051000833700331.png"\; state="\{\{state\}\}">n</figure-callout>}}_2}\&rsqb;\&rsqb;\&CenterDot;\cos \mathrm{\&theta;i}---\left(3\right)$

Above-mentioned by making (2), (3) meet above-mentioned condition: a＞b, at above-mentioned distance L, can derive following (4) formula.

$L>2\&CenterDot;\frac{\mathrm{\&Lambda;}}{\mathrm{\&lambda;}}t\&CenterDot;\tan \&lsqb;{\sin }^{-1}\&lsqb;\frac{\sin \mathrm{\&theta;i}}{{\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="C20051000833700271.png,C20051000833700331.png"\; state="\{\{state\}\}">n</figure-callout>}}_2}\&rsqb;\&rsqb;\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="cos"\; filenames="C20051000833700271.png,C20051000833700331.png"\; state="\{\{state\}\}">cos</figure-callout>}}^2\mathrm{\&theta;i}---\left(4\right)$

But, under the width w of surface reflection light image becomes situation with respect to the above-mentioned size that can not ignore apart from a, b, the condition enactment that preferably will be used to obtain above-mentioned distribution curve for as following (5) formula.Under this situation,, replace (4) formula, can derive (6) formula about above-mentioned distance L.Have again,, for example as shown in Figure 9, can be set at intensity with respect to the peak value of surface reflection light image at l/e about the width w of above-mentioned surface reflection ²The width in above zone.

$a-\frac{\mathrm{<figure-callout\; id="2"\; label="w"\; filenames="C20051000833700271.png,C20051000833700331.png"\; state="\{\{state\}\}">w</figure-callout>}}{2}>b+\frac{w}{2}---\left(5\right)$

$L>\frac{\mathrm{\&Lambda;}}{\mathrm{\&lambda;}}\cos \mathrm{\&theta;i}\&CenterDot;\&lsqb;2t\&CenterDot;\tan \&lsqb;{\sin }^{-1}\&lsqb;\frac{\sin \mathrm{\&theta;i}}{{\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="C20051000833700271.png,C20051000833700331.png"\; state="\{\{state\}\}">n</figure-callout>}}_2}\&rsqb;\&rsqb;\&CenterDot;\cos \mathrm{\&theta;i}+w\&rsqb;---\left(6\right)$

In the optical gauge that this embodiment relates to, when substrate 3 only leaves predetermined distance and is provided with sensing head 1, adjust the position relation of condenser 114 and CCD122, make substrate 3 and the distance of CCD122 satisfy the relation of above-mentioned (4) formula or (6) formula.In addition,, adopt lens with following such focal length as condenser 114, promptly in the relation of above-mentioned position, become surface reflection optically focused on CCD122 and back reflected light also can be regarded as the state of optically focused.Have again, can be based on structure of the substrate of determination object and electrode pattern, light-projecting portion 11 etc., specific required Λ, λ, θ i, t, the n of specific above-mentioned distance L in advance ₂

By carrying out aforesaid adjustment, in CCD122, can generate the distribution curve of the group of the surface reflection light image of same number and backside reflection light image by each number of times assortment successively.The CPU21 of above-mentioned controller 2 extracts the data of the surface reflection light image that each number of times is shown from the light interception data that this distribution curve is shown, use the cycle graph of their strength detection electrode.

Have, it is prerequisite that this embodiment has overwhelming dominance with 0 diffraction light than the diffraction light of other number of times again, but sometimes because the shape of electrode 31, even periodically assortment, 0 time diffraction light is not maximum yet yet.For this situation of correspondence, at to having shone the reflected light that produces from light time of light-projecting portion 12, be specular light with the congener substrate 3 of the determination object that does not have assortment electrode 31, obtain scope in advance with respect to the incoming position of CCD122, login is in storer 22, during mensuration, as long as extract the largest peaks and second largest peak value from the light income of the above-mentioned scope of logining, with its specific be to get final product with 0 corresponding data of diffraction light.

Can suppose reflecting surface from the surperficial 3a of substrate 3 to the 3b of the back side, obtain to theoretical property from the position of the reflected light incident of the substrate 3 of assortment electrode 31 not.Under this situation, the incoming position that can set has theoretically only left scope than the position of the predetermined distance c little apart from a of above-mentioned (2) formula to positive negative direction, with it as the scope of above-mentioned incoming position and login.

Figure 10 illustrates CPU21 and relates to the order of extracting above-mentioned surface reflection light intensity.Have again, because this is equivalent to the detailed sequence of the step 2 of Figure 12 described later in proper order, so each step is shown with 20 later numerals.In addition, in Figure 10 and the following description, each step is simply remembered work " ST ".

As mentioned above, the surface reflection of described 0 diffraction light and backside reflection light intensity all than the reflected light height of other number of times, in addition, have position relation arranged side by side in the distribution curve of light income.Therefore, in this order, in ST21, extract the maximum and second largest picture of peak value of peak value in each the reflected light picture from light interception data.Then,, there are not after other peak values corresponding two the reflected light pictures conduct of specific and these peak values and 0 corresponding reflected light picture of diffraction light between the two having confirmed that the distance between these peak values is to approach the value of above-mentioned distance b.

In the ST22 that follows, a certain side of specific and above-mentioned 0 corresponding a pair of reflected light picture of diffraction light is as surface reflection.As above-mentioned shown in Figure 5, back reflected light reflects on the position of specific surface reflected light away from light-projecting portion 11, advance abreast with surface reflection, therefore, on the CCD122 also optically focused on position away from light-projecting portion 11.Thereby in ST22, the picture (if the coordinate axis of Fig. 6 is exactly the little picture of coordinate) that approaches light-projecting portion 11 in the specific above-mentioned a pair of reflected light picture is as the surface reflection light image.

In addition, in the distribution curve of the light income that this embodiment relates to, the surface reflection light image of each number of times be separated by above-mentioned Fig. 7 apart from a by number of times assortment successively.So in the ST23 that follows, the position of the doubly above-mentioned value apart from a (m＜0, m＞0) of m has only been left in specific position from above-mentioned 0 time surface reflection light image, as the position of m time surface reflection light image.Have again, can obtain the occurrence of a by above-mentioned (2) formula.

In ST24, obtain the intensity of each the surface reflection light image after specific.As this intensity, in this embodiment, as shown in figure 11, at each surface reflection light image P _m, P _M+1, obtain respectively and be included in width w _m, w _M+1Scope in the integrated value of data.Width w under this situation is arranged again _m, w _M+1Also same with the width w shown in above-mentioned Fig. 9, can be made as and obtain the l/e of peak value ²The regional corresponding value of above intensity.

Figure 12 illustrates the related a series of order of mensuration of the assortment figure of electrode.Have again, in this figure and the following description, also each step is omitted and be depicted as " ST ".

At first, in initial ST1, be taken into and measure the processing of handling necessary light interception data.In this is handled, driven by the sensor control circuit 27 after the light projector circuit 13 and light receiving circuit 14 of sensing head 1 side, the A/D conversion is stored in the storer 22 from the light income signal of CCD122.

In the ST2 that follows,, detect the surface reflection light intensity of each number of times by the light interception data that obtains is carried out the order of above-mentioned Figure 10 in ST1.In the ST3 that follows, read the related theoretic surface reflection light intensity (being the data that comprise a plurality of intensity of each diffraction light) of assortment figure of regulation from above-mentioned decision table.In ST4,, utilize least square method to calculate both error σ at the intensity on each intensity in above-mentioned ST2, extracted and the above-mentioned theory.

Below, by each being logined the assortment figure execution ST3 in decision table, 4 processing, obtain error σ successively.When obtaining error σ at whole assortment figures of being logined, ST5 is a "Yes", and in the ST6 that follows, specific above-mentioned error σ assortment figure hour is as the structure of determination object.Afterwards, in ST7, export the width d and the height h of the electrode of this cycle graph after specific to the outside, as measurement result.

The processing that CPU21 carries out as optical gauge such as above-mentioned shown in Figure 12.In addition, whether good CPU21 also can carry out differentiating from this measurement result assortment figure the processing of above-mentioned electrode.

Like this, according to above-mentioned processing, can remove the back reflected light of the influence of the characteristic of being decided plate easily, and only carry out the mensuration of surface reflection, therefore, can carry out high-precision mensuration the cycle graph of electrode.

In above-mentioned Fig. 3～Fig. 5, only show the electrode 31 of a direction assortment on the substrate, but in the substrate 3 that the LCD of reality uses, the matrix assortment source electrode line and two kinds of electrodes of gate line, above-mentioned banded light 5 shines along the assortment of the electrode that becomes determination object.Under this situation, carry out mensuration processing accurately, just need to adjust the position of sensing head 1, make banded light 5 is radiated on the position that does not relate to the opposing party's electrode with respect to substrate 3 to the electrode of determination object.

Figure 13 shows at the position relation of the electrode of determination object and banded light 5 and contrasts good example and non-good example.Among the figure, being source electrode line along the electrode 31a of horizontal direction (y direction) assortment, is gate line along the electrode 31b of vertical direction (x direction) assortment.In addition, in each zone that fences up with these electrodes 31a, 31b, thin film transistor (TFT) (TFT) 32 is set.

At this, under with the situation of source electrode line 31a as determination object, above-mentioned banded light 5 just shines along the y direction of principal axis.Banded light 5 under this situation preferably is radiated on the position that does not relate to gate line 31b and thin film transistor (TFT) 32 shown in the arrow A among the figure.Shown in arrow B and C, when banded light 5 shines on the position that relates to gate line 31b, just produce the caused diffraction of light of assortment cycle of source electrode line 31a hardly, be difficult to obtain the light interception data shown in above-mentioned Fig. 6 C.

Particularly under the situation of the electrode structure of checking large substrate, on substrate, set after a plurality of determination objects zone, substrate or sensing head 1 are moved, each determination object zone is measured with sensing head 1 contraposition successively.But,, therefore,, be difficult to banded light 5 is shone on the suitable position only mechanically with substrate and sensing head 1 contraposition because the interelectrode interval of this kind substrate is atomic little.

Therefore, among the embodiment that illustrates below, before mensuration is handled, when making the irradiation position minute movement of banded light 5, use the distributed data of the light income that on each position, obtains to come the irradiation position of particular assay the best.

Figure 14 illustrates the structure of testing fixture of the electrode inspection usefulness of LCD substrate.This testing fixture also comprises the XY objective table 7 of supporting substrates 3, two video cameras 9 and two controller 2S, 8 except sensing head 1.

XY objective table 7 is configured in the adjacent of the manufacturing installation 50 of substrate 3, has received after the substrate 3 that manufacturing installation 50 is sent, and can support it and it is moved on x direction and y direction.Sensing head 1 and video camera 9 utilize special- purpose support sector 71,72 respectively, and fixed configurations is above XY objective table 7.Have, the structure of sensing head 1 is identical with the situation shown in above-mentioned Fig. 2 and Fig. 4 again.

On the substrate 3 of this embodiment, set in a plurality of determination objects zone 300, in each determination object zone 300, be provided be used to make this zone and sensing head 1 below the alignment mark (not shown) of contraposition.Above-mentioned controller 8 is connected with video camera 9 with XY objective table 7, handles from the position of extracting alignment mark behind the image of video camera 9, extracts the result based on this, the action of control XY objective table 7.

Another controller 2S has added the function that is used to control and check XY objective table 7 in the controller shown in above-mentioned Fig. 1,22.This controller 2S is connected with sensing head 1 with controller 8, utilization is communicated by letter with controller 8, in the action of control XY objective table, handle light interception data from sensing head 1, adjust the position relation that makes determination object zone 300 and sensing head 1 become the best.

At this, use Figure 15, describe at the processing of the light interception data of the position adjustment that is used for the XY objective table.

Under the position shown in the arrow A of above-mentioned Figure 13 irradiation situation, a plurality of diffraction lights that the electrode 31a by determination object causes have been produced from the banded light 5 of the light-projecting portion 11 of sensing head 1.Like this, in the light interception data in this case, shown in Figure 15 (1), become the surface reflection light image of each number of times and backside reflection light image alternately and by the state of number of times assortment successively.With respect to this, shown in above-mentioned arrow B, C, shining to the position of the electrode outside the determination object under the situation of banded light 5, just become and be difficult to produce the state that causes optical diffraction by the electrode 31a of determination object.Therefore, in light interception data, shown in Figure 15 (2), become remove 0 time reflected light as P ₀, p ₀Outside, do not manifest the state of significant reflection light image.

In this embodiment, the theoretical curve of the light interception data under the situation of suitably having shone banded light 5 to determination object zone 300 in advance, obtain the surface reflection and the backside reflection light intensity of the stipulated number (being made as secondary in the example of Figure 15) except 0 time, with the intensity that meets them is benchmark, and login is in the storer of controller 2S.On the other hand, at the light interception data of the reality that obtains from above-mentioned CCD122, the also specific surface reflection light image P that should comprise secondary ₂With backside reflection light image p ₂Region R, extract the light income in this region R.Then, by comparing with the said reference value, judge whether to have obtained to measure needed diffraction light from the light income that this region R is extracted.

Have again, during region R in specific light interception data, according to the order identical with above-mentioned Figure 10, extracted peak-peak and second largest peak value zone arranged side by side after, based on 2 times the value apart from a of above-mentioned (2) formulas, the position of specific region R.In addition, can obtain light income in the region R by the light interception data in this region R of integration.

Figure 16 illustrates the processing sequence of above-mentioned testing fixture.The main body of carrying out these a series of orders is above-mentioned controller 2S, but carries out the mobile control of XY objective table 7 by controller 8.Have, among this embodiment, the direction of the electrode of determination object institute assortment also is the y direction, carries out the position adjustment of XY objective table 7 along the x direction again.

According to substrate 3 has been delivered on the above-mentioned XY objective table 7, begin the order of Figure 16.In initial ST101, the position based on above-mentioned alignment mark adjustment XY objective table 7 makes first determination object zone 300 come the below of sensing head 1.

In ST102, the counter m that will be used to count the adjustment number of times of XY objective table 7 makes zero.In the ST103 that follows, drive sensing head 1, input is from the light interception data of CCD122.Then, in ST104,, extract the light income in this region R from the specific above-mentioned region R of light interception data.Then, in ST105, the light income that the extracts current location with the XY objective table is kept in the storer.Have again, can utilize the coordinate of the initial point of the objective table in the xy coordinate system for example to represent the current location of XY objective table 7.

In ST106, with above-mentioned XY objective table 7 along the only mobile ormal weight Δ of x direction of principal axis x.In ST107, above-mentioned counter m is updated to adds one value.If the m after this upgrades turns back to ST103 for the threshold value M of regulation or below it from ST108.

As mentioned above, in the position of adjusting XY objective table 7, carries out the processing that is taken into light interception data for M time, make the interior light income of each region R corresponding with the position foundation of XY objective table and be kept in the storer.When this processing finishes, just advance to ST109, the light income of being preserved is compared with above-mentioned reference value.Then, differentiate with and the position of the minimum corresponding XY objective table 7 of light income of the difference of reference value are optimum determining positions.

In ST110, XY objective table 7 is moved on the optimum position of differentiating among the above-mentioned ST109, in ST111, carry out to measure and handle.Have again, measure in the processing at this and carry out and above-mentioned identical order shown in Figure 12, therefore, omit detailed explanation at this.

Below, about other determination object zone 300, carry out the processing of ST101～111 similarly.When finishing for the processing in whole determination object zones 300, ST112 just becomes "Yes", advances to ST113, based on the measurement result in each determination object zone 300, judges whether the assortment figure of above-mentioned electrode is good.Then, in ST114, to the result of the above-mentioned determination processing of output such as monitor 2a (shown in Figure 14), not shown upper system, end process then.

Order according to above-mentioned Figure 16, owing to can both on the position shown in the arrow A among above-mentioned Figure 13, shine banded light 5 and measure processing for whole determination object zones 300, therefore, use can be measured the assortment figure of above-mentioned electrode accurately by the surface reflection light image of the diffraction light of the electrode generation of determination object.Like this, can improve the precision of inspection significantly, provide a kind of reliability high testing fixture.

Have again, in the testing fixture of the foregoing description, for explanation simply, the sensing head 1 of having supposed fixed configurations, but in the specification of reality, preferably can dispose sensing head 1 up or down, make it possible to aim at the assortment periods lambda of the electrode of checking object and change the distance L of above-mentioned (4) formula.Under this situation,,, can adjust the height of sensing head 1 according to this value by obtain the value of L to the periods lambda of the thickness t of the substrate 3 of controller 2S input checking object and electrode 31.In addition, when measuring processing, from the processing (with the corresponding processing of the ST23 of above-mentioned Figure 10) of the surface reflection light image of specific each number of times of light interception data, also can be above-mentioned apart from a by obtaining based on the Λ value of being imported, come the position of specific each surface reflection light image.

Claims (9)

1. optical gauge, to have on the substrate of light transmission works with the periodicity assortment as determination object, execution has used the mensuration of diffraction light to handle, this diffraction light is to produce when a plurality of periodic works irradiates light of institute's assortment of above-mentioned substrate surface, it is characterized in that having:

Light-projecting portion, it will comprise the light that focuses on along the direction of the assortment direction of said structure thing with in the cross section of the face of the direction of the optical axis of the light of the surface irradiation of aforesaid substrate, with respect to the surface of aforesaid substrate, the mode that becomes the plane of incidence with above-mentioned cross section is shone by oblique incidence;

Light accepting part, it includes imaging apparatus, described imaging apparatus has a plurality of light pixels that are subjected to of institute's assortment, and the direction of this assortment is the direction that is comprised by in the face of determining along the direction of the direction of the assortment direction of said structure thing and the optical axis by the light after the surperficial normal reflection of aforesaid substrate

On above-mentioned imaging apparatus, determine above-mentioned light-projecting portion with respect to the irradiating angle of the distance of aforesaid substrate and irradiates light, include distance and the angle of the light accepting part of above-mentioned imaging apparatus with respect to aforesaid substrate, make m time diffraction light of back reflected light incide m time diffraction light of the surface reflection that produces by above-mentioned irradiates light and (m+1) between the position of inferior diffraction light incident, wherein m is an integer arbitrarily, in the diffraction light that on aforesaid substrate, reflects, will just be made as away from a side of light-projecting portion.

2. optical gauge as claimed in claim 1, it is characterized in that, have extraction element and determinator, described extraction element based in the light income that obtains by above-mentioned imaging apparatus, with the above-mentioned light that is subjected to the maximal value in the distributed data of the assortment directional correlation of pixel, and the position of above-mentioned light-projecting portion and light accepting part relation, from the distributed data of above-mentioned light income, individually extract the surface reflection light intensity of each number of times, described determinator uses each the surface reflection light intensity that is extracted by the said extracted device, measures the said structure thing.

3. optical gauge as claimed in claim 2, it is characterized in that, have input media and calculating apparatus, the assortment cycle of the works of described input media input determination object, described calculating apparatus uses the assortment cycle by above-mentioned input media input, calculate the interval of incoming position of the surface reflection of each number of times in the above-mentioned imaging apparatus

The said extracted device is from the light income that is obtained by above-mentioned imaging apparatus, with the above-mentioned light that is subjected to the largest peaks and second largest peak value part arranged side by side in the distributed data of the assortment directional correlation of pixel, in the diffraction light that will on aforesaid substrate, reflect with approach the corresponding peak value of a side of light-projecting portion, incoming position as 0 time surface reflection is specific in addition, to only leave the position of the m distance doubly that is equivalent to the interval that calculates by above-mentioned calculating apparatus from this incoming position simultaneously, incoming position as m time surface reflection is specific in addition, based on specific each incoming position, extract the surface reflection light intensity of each number of times.

4. optical gauge as claimed in claim 1 is characterized in that having:

Entering device, it is logined in advance and incides above-mentioned in the above-mentioned imaging apparatus with reflected light and be subjected to the position of light with the assortment directional correlation of pixel, and this reflected light is to produce to the light time of having shone from light-projecting portion with the substrate of the determination object identical type of assortment said structure thing not;

Extraction element, it is at the substrate of said determination object, from the distributed data of the locational light income of login above-mentioned entering device that incide above-mentioned imaging apparatus, obtain maximal value, based on the position relation of this maximal value and above-mentioned light-projecting portion and light accepting part, from the distributed data of all light incomes of above-mentioned imaging apparatus, individually extract the surface reflection light intensity of each number of times;

Determinator, it uses each the surface reflection light intensity that is extracted by the said extracted device, measures the said structure thing.

5. optical gauge as claimed in claim 4, it is characterized in that, have input media and calculating apparatus, the assortment cycle of the works of described input media input determination object, described calculating apparatus uses the assortment cycle by above-mentioned input media input, calculate the interval of incoming position of the surface reflection of each number of times in the above-mentioned imaging apparatus

The login of above-mentioned entering device is based on inciding the above-mentioned scope that obtained in advance with the position of the assortment directional correlation of pixel by light in the above-mentioned imaging apparatus with reflected light, this reflected light is to produce to the light time of having shone from light-projecting portion with the substrate of the determination object identical type of assortment said structure thing not

The said extracted device, from at above-mentioned the light largest peaks and second largest peak value part arranged side by side and in the scope of login above-mentioned entering device of above-mentioned imaging apparatus of being subjected to the assortment direction of pixel, in the diffraction light that will on substrate, reflect with approach the corresponding peak value of a side of light-projecting portion, incoming position as 0 time surface reflection is specific in addition, simultaneously, distributed data for all light incomes of above-mentioned imaging apparatus, to only leave the position of the m distance doubly that is equivalent to the interval that calculates by above-mentioned calculating apparatus from the incoming position of above-mentioned 0 time surface reflection, incoming position as m time surface reflection is specific in addition, based on specific each incoming position, extract the surface reflection light intensity of each number of times.

6. as each described optical gauge in the claim 1～5, it is characterized in that, have position regulator and control device, described position regulator is used to adjust the position with respect to the light-projecting portion of the direction vertical with the assortment direction of said structure thing, described control device uses the distributed data of the light income that is obtained by above-mentioned imaging apparatus, the position adjustment process that control is undertaken by above-mentioned position regulator

Above-mentioned control device comprises: when making above-mentioned position regulator carry out position adjustment process, extract not the device of the light income of the scope corresponding with two sides of the back reflected light of 0 time surface reflection and 0 time under this state from the distributed data of the light income that obtains at every turn; The device that above extracted light income is compared with specified reference value; Use the result of above-mentioned comparison process, differentiate the device of the position relation that is suitable for measuring at aforesaid substrate and light-projecting portion.

7. optical measuring method will have on the substrate of light transmission works with the periodicity assortment as determination object, and the diffraction light that produces when receiving a plurality of periodic works irradiates light to institute's assortment of this substrate surface is characterized in that,

To comprise the light that focuses on along the direction of the assortment direction of said structure thing with in the cross section of the face of the direction of the optical axis of the light of the surface irradiation of aforesaid substrate, surface with respect to aforesaid substrate, the mode that becomes the plane of incidence with above-mentioned cross section is shone by oblique incidence

Dispose imaging apparatus, described imaging apparatus has a plurality of light pixels that are subjected to of institute's assortment, the direction of this assortment is the direction that is comprised by in the face of determining along the direction of the direction of the assortment direction of said structure thing and the optical axis by the light after the surperficial normal reflection of aforesaid substrate, make m time diffraction light of back reflected light incide the diffraction light that produces by above-mentioned irradiates light surface reflection m time diffraction light and (m+1) between the position of inferior diffraction light incident, thereby receive reflected light from substrate with respect to above-mentioned irradiates light, wherein m is an integer arbitrarily, in the diffraction light that on aforesaid substrate, reflects, will just be made as away from a side of light-projecting portion.

8. optical measuring method as claimed in claim 7, it is characterized in that, after above-mentioned imaging apparatus reception reflected light, based on the maximal value in the distributed data of the light income that obtains, and towards the position relation of light-projecting portion with the light accepting part that includes above-mentioned imaging apparatus of the surface irradiation light of aforesaid substrate, from the distributed data of above-mentioned light income, individually extract the surface reflection light intensity of each number of times, use each the surface reflection light intensity that is extracted, measure the said structure thing.

9. as claim 7 or 8 described optical measuring methods, it is characterized in that, carry out repeatedly and make irradiation position with respect to the light of said structure thing when the direction vertical with the assortment direction of works moves, the distributed data of the light income that use is obtained by imaging apparatus is differentiated the step whether above-mentioned irradiation position is the position that is suitable for measuring

In the step of above-mentioned differentiation, carry out: the step of extracting not the light income of the scope corresponding from the distributed data of the light income that obtains by above-mentioned imaging apparatus with two sides of the back reflected light of 0 time surface reflection and 0 time; The step that above extracted light income is compared with specified reference value,

When having obtained surpassing the light income of said reference value, differentiate for irradiation position and be suitable for mensuration at the light in this moment.

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