JP2008288303A - Charge amount evaluation element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To evaluate a charge amount of a workpiece in a manufacturing apparatus quantitatively with high spatial resolution and to allow reuse of an evaluation element with respect to a charge amount evaluation element.
A charge amount evaluation unit that quantitatively evaluates the total amount of charge accumulated on the surface of a substrate to be processed is provided with a base body 1 having at least a conductive surface, and an electro-optic effect film 5 disposed on the base body 1. And an isolated transparent electrode 6 disposed on the electro-optic effect film 5 and an insulating protective film 7 covering a region of the substrate 1 that does not overlap the projection with the electro-optic effect film 5.
[Selection] Figure 1

Description

  The present invention relates to a charge amount evaluation element, and in particular, for evaluating with high sensitivity and high resolution the amount of charge that a wafer surface enjoys in the manufacturing process of an electronic device, especially in the manufacturing process of a magnetic disk head element or the like. The present invention relates to a charge amount evaluation element having a characteristic configuration.

  In the manufacturing process of a magnetic disk head element, which is increasing in density, the magnetic disk head element itself is damaged by static electricity and electrical stress, and this is one of the main causes of a decrease in yield due to the downsizing of the magnetic disk head element. It has become one.

  Therefore, in order to prevent the yield from being reduced due to such damage, as an antistatic measure in the assembly process, evaluation by a charged plate monitor or surface potential meter is performed, and the amount of charge in the process equipment using a probe Evaluation is also being conducted.

  In order to evaluate the charge amount, an element for evaluating the charge amount and the element damage due to the charge due to the dielectric breakdown of the insulating thin film between the opposing electrodes is targeted for semiconductor manufacturing apparatuses and magnetic disk head element manufacturing apparatuses. It is disclosed.

For example, it has been proposed to stack a pair of electrodes via an insulating film and evaluate the charge amount by dielectric breakdown of the insulating film sandwiched between the pair of electrodes (for example, Patent Document 1 or Patent Document 2). reference).
JP 2004-253610 A JP 2001-349869 A

  However, in the charge amount evaluation using the insulating film type element, there is a problem that it is only possible to determine whether or not the charge amount is larger than the charge amount reference value determined by the material, film thickness, antenna size, etc. of the insulating film. .

  In other words, the magnetic disk head manufacturing apparatus and the semiconductor process apparatus are considered to deteriorate in time series and increase static electricity and abnormal charges on the workpiece. Although it is necessary to evaluate the charge amount, such a quantitative charge amount evaluation is difficult for an insulating film type element.

  Of course, it is possible to quantitatively evaluate the charge amount as an element set by arranging a plurality of insulating film type elements with different insulating thin film thicknesses close to each other, but the sensitivity is discrete. Since a plurality of elements are used as a group, there is a problem that the spatial resolution is lowered.

  Furthermore, in the case of an insulating film type element, since the charge amount is evaluated based on the breakdown of the insulating film, it cannot be reused, and there is a problem that running cost is increased.

  Accordingly, an object of the present invention is to make it possible to evaluate the charge amount of the workpiece in the manufacturing apparatus quantitatively and with high spatial resolution, and to enable reuse of the evaluation element.

FIG. 1 is a block diagram showing the principle of the present invention, and means for solving the problems in the present invention will be described with reference to FIG.
To solve the above problems, the present invention provides a charge amount evaluation element for quantitatively evaluating a total amount of charge accumulated on the surface of a substrate to be processed. Is projected onto the electroconductive substrate 1, the electro-optic effect film 5 disposed on the substrate 1, the isolated transparent electrode 6 disposed on the electro-optic effect film 5, and the electro-optic effect film 5 of the substrate 1. A charge amount evaluation unit 4 including an insulating protective film 7 covering a non-overlapping region is provided.

  As described above, by using the electro-optic effect film 5 for the charge evaluation, the charge amount accumulated in the isolated transparent electrode 6 can be quantitatively evaluated, and the single charge amount evaluation unit 4 can quantitatively charge the charge. Since the quantity can be quantitatively evaluated, the spatial resolution is increased.

  That is, when this charge amount evaluation element is inserted into the manufacturing apparatus, electric charges generated during the process or handling are accumulated in the isolated transparent electrode 6, and an electric field is generated between the conductive portion on the surface of the substrate 1 having no electric charge. As a result, the refractive index and the polarization direction of the electro-optic effect film 5 change according to the strength of the electric field, so that the amount of charge accumulated in the isolated transparent electrode 6 can be determined by measuring the amount of change in the refractive index and the polarization direction. It is possible to measure, and it is possible to quantitatively evaluate the charge amount by the manufacturing apparatus.

  Moreover, since the charge amount is evaluated non-destructively by releasing the charge accumulated in the isolated transparent electrode 6, it can be reused, thereby reducing the running cost.

  The base 1 in this case may be constituted by a transparent insulating substrate 2 and a transparent electrode 3 provided on the transparent insulating substrate 2, or may be constituted by a transparent conductive substrate itself such as a ZnO single crystal. Is also good.

  Alternatively, the substrate 1 may be constituted by an insulating substrate and a reflective electrode provided on the insulating substrate, or may be constituted by a reflective conductive substrate itself such as an Al substrate.

The electro-optic effect film 5 may be a ferroelectric film such as PLZT whose refractive index changes with voltage, or a liquid crystal, particularly a cholesteric liquid crystal.
In addition, when a cholesteric liquid crystal having a memory effect is used, the final state can be maintained semi-permanently even if the charge of the isolated transparent electrode 6 escapes. Even in the case where the discharge occurs, the charge amount in the manufacturing apparatus can be accurately evaluated.

Further, by returning the alignment state of the cholesteric liquid crystal to the initial state, it can be used again for the evaluation of the charge amount, so that the running cost can be reduced.
Furthermore, since the transmittance of a cholesteric liquid crystal changes depending on the electric field, unlike a normal liquid crystal, it is possible to evaluate a measurement system that is simpler than a refractive index measurement system and includes only a laser and a photodetector.

  In addition, it is desirable to provide a plurality of the above-mentioned charge amount evaluation units 4 on the same substrate 1, whereby it becomes possible to accurately evaluate the in-plane distribution of the charge amount on the surface of the substrate to be processed.

According to the present invention, it is possible to quantitatively evaluate the charge received by a wafer as a workpiece in an apparatus for manufacturing an electronic device such as a magnetic disk head element or a semiconductor element. It is possible to evaluate element damage caused by plasma instability and obtain guidelines for producing electronic devices with a high yield.
Furthermore, since the process conditions can be fed back in a short time, the development man-hours can be reduced.

  Further, since the charge amount is evaluated nondestructively, the charge amount evaluation element can be repeatedly reused, thereby reducing the running cost.

  The charge amount evaluation element of the present invention has a transparent substrate comprising a transparent electrode provided on a transparent insulating substrate such as glass or a transparent conductive substrate, or a reflective electrode such as an Al electrode on an insulating substrate such as glass. A ferroelectric film whose refractive index is changed by a voltage such as PLZT or an electro-optic effect film such as a liquid crystal, particularly a cholesteric liquid crystal having a memory function, is provided on the reflective substrate formed of a reflective substrate or a reflective conductive substrate. In addition, an isolated transparent electrode is provided on the electro-optic effect film to constitute a charge amount evaluation unit, and the refractive index or polarization of the electro-optic effect film changes depending on the charge generated by the charge accumulated in the isolated transparent electrode. The amount of charge is evaluated by measuring the amount of change in direction.

Here, the measurement accuracy of the charge amount when the electro-optic effect film is used is evaluated.
If a PLZT single crystal thin film by the aerosol deposition method is used as the electro-optic effect film, the electro-optic constant is 1.02 × 10 ⁻¹⁰ m / V when a 633 nm He—Ne laser is used as the light source. Become.
Therefore, in order for the refractive index to change by 0.0001,
0.0001 / 1.02 × 10 ⁻¹⁰ [m / V] = 9.8039216 × 10 ⁵ V / m
Of electric field is required.

Here, when the interval between the transparent electrode and the isolated transparent electrode is 1 μm,
9.8039216 × 10 ⁵ [V / m] × 10 ⁻⁶ [m] = 0.9.8039216V
Is required.

At this time, if the size of the isolated transparent electrode serving as an antenna is 200 μm × 200 μm,
The relative dielectric constant ε of the electro-optic effect film (here PZT) is 1000
The area S of the isolated electrode is 4 × 10 ⁻⁸ m ²
The electrode spacing d is 1 μm = 10 ⁻⁶ m
The dielectric constant ε _{0 of} vacuum is 8.86 × 10 ⁻¹²
Then, the electrostatic capacitance C of the charge amount evaluation unit is
C = ε ₀ εS / d≈3.54 × 10 ⁻¹⁰ F
It becomes.

Here, since Q = CV, in order to generate a potential of 0.9.8039216 V, Q = 3.54 × 10 ⁻¹⁰ F × 0.9.8039216 V≈0.347 nC
It is sufficient that the amount of charge is accumulated.

  Therefore, the refractive index resolution of 0.0001 can be obtained with a charge amount of 0.35 nC, and the capacitance C increases by decreasing the electrode interval d and / or increasing the area S of the isolated electrode. As a result, the amount of charge Q required to generate the necessary potential is reduced, so that the sensitivity can be further improved.

On the other hand, a commercially available thin film refractive index measuring device, for example, FilmTek 4000 (product model number manufactured by SCI), can measure with a resolution of 2 × 10 ⁻⁵ , so that the refractive index change is 0.0001 (= 10 ⁻⁴ ). There is no problem in measuring.

Incidentally, since the breakdown charge amount of the thin film magnetic head is 0.2 nC, for example, it can be measured by using a thin film refractive index measuring device having a resolution of 2 × 10 ⁻⁵ , and the charge amount evaluation unit By reducing the electrode interval d and / or increasing the area S of the isolated electrode, the charge amount Q required for the refractive index change can be made sufficiently small, so that even if the resolution is lower than 2 × 10 ⁻⁵ , the thin film It becomes possible to detect the destruction of the magnetic head.

  Since the spot diameter of the laser serving as the light source in the measurement system can be reduced to about 10 μm, the refractive index change can be easily measured by setting the size of the isolated transparent electrode to 200 μm □.

Based on the above, the charge amount evaluation element of Example 1 of the present invention will now be described with reference to FIGS.
See Figure 2
First, the transparent electrode 12 made of an ITO film having a thickness of, for example, 1 μm is formed on the surface of the transparent insulating substrate 11 made of a glass wafer by vapor deposition.

Next, a PLZT film [Pb _1-x La _x (Zr _1-y Ti _y ) _{1-x / 4} O ₃ (0 <x <0.3, 0 <y <1) film] 13 is formed by sputtering. For example, after forming a film thickness of 0.5 μm, the PLZT film 13 is etched by dry etching by reactive ion etching (RIE) using a resist pattern (not shown) as a mask, for example, an electro-optical size of 200 μm × 200 μm. The effect film 14 is formed.

Next, the SiO ₂ film 15 is formed to a thickness of 0.7 μm, for example, by sputtering, and the electro-optic effect film 14 is completely embedded.

See Figure 3
Next, the insulating protective film 16 is obtained by polishing flatly until the surface of the electro-optic effect film 14 is exposed by chemical mechanical polishing (CMP).

  Next, an ITO film 17 having a film thickness of 0.5 μm, for example, is formed by vapor deposition, and then dry etching is performed by reactive ion etching using a resist pattern (not shown) as a mask, so that it is in the same position as the electro-optic effect film 14. By forming the isolated transparent electrodes 18 of the same size, the basic configuration of the charge amount evaluation element of Example 1 of the present invention is completed.

See Figure 4
FIG. 4 is a diagram illustrating the configuration of the charge amount evaluation element according to the first embodiment of the present invention. The charge amount evaluation unit including the electro-optic effect film 14 sandwiched between the transparent electrode 12 and the isolated transparent electrode 18 is two-dimensional. The configuration is arranged in a matrix.
In the figure, a case where 100 charge amount evaluation units are arranged on the transparent insulating substrate 11 is shown, but the arrangement number is arbitrary.

Next, with reference to FIG. 5, a charge amount evaluation method using the charge amount evaluation element of Example 1 of the present invention will be described.
See Figure 5
FIG. 5 is an explanatory diagram of the configuration of a refractive index change measurement system for evaluating the charge amount. From the laser light source 21, the two polarizing plates 22 and 23 arranged in crossed Nicols, and the photodetector 24. Thus, the charge amount evaluation element 10 is installed between the two polarizing plates 22 and 23, and the change in the refractive index of the electro-optic effect film 14 constituting the charge amount evaluation element 10 by the photodetector 24 is defined as the change in light intensity. Measure.

  When this charge amount evaluation element 10 is carried into an electronic device manufacturing apparatus such as a plasma apparatus, charges generated during the process are accumulated in the isolated transparent electrode 18, whereas the transparent electrode 12 is protected by the insulating protective film 16. Therefore, since the charge state does not change before being carried into the apparatus, an electric field is applied to the electro-optic effect film 14 in accordance with the amount of charge accumulated in the isolated transparent electrode 18, so that the refractive index changes.

After carrying out the charge amount evaluation element 10 from the apparatus, by installing the charge amount evaluation element 10 between the two polarizing plates 22 and 23 of the measurement system shown in FIG. 5, and measuring the change in the refractive index, The charge amount of the isolated transparent electrode 18 can be quantitatively evaluated.
Note that the transparent electrode 12 is preferably grounded when measuring the refractive index.

  Further, after the charge amount is evaluated, the charge of the charge amount evaluation element is returned to the initial state by releasing the accumulated charge by bringing the isolated transparent electrode 18 into contact with the ground terminal. Can be used for

  As described above, the charge amount evaluation element according to the first embodiment of the present invention makes it possible to evaluate the charge amount of a wafer to be processed in the electronic device manufacturing apparatus in a non-destructive and quantitative manner with high spatial resolution. Since it is available, the running cost can be reduced.

  The range of charge amount that can be evaluated can be adjusted by the film thickness of the electro-optic effect film 14, and the spatial resolution can also be changed by the size of the isolated transparent electrode 18.

Next, with reference to FIG. 6, the charge amount evaluation element of Example 2 of the present invention will be described.
See FIG.
First, a PLZT film having a thickness of 0.5 μm, for example, is formed on a transparent conductive substrate 31 made of a ZnO single crystal wafer by a sol-gel method, and then dried by reactive ion etching using a resist pattern (not shown) as a mask. The electro-optic effect film 32 having a size of, for example, 200 μm × 200 μm is formed by etching.

Next, a SiO ₂ film having a film thickness of 0.7 μm, for example, is formed by CVD and the electro-optic effect film 32 is completely embedded, and then polished flat by CMP until the surface of the electro-optic effect film 32 is exposed. Thus, the insulating protective film 33 is obtained.

  Next, after forming an ITO film of 0.5 μm, for example, by sputtering, the resist pattern (not shown) is used as a mask, and dry etching by reactive ion etching is performed at the same position as the electro-optic effect film 32 so as to be isolated and transparent. By forming the electrode 34, the basic configuration of the charge amount evaluation element of Example 2 of the present invention is completed.

The operation principle of this charge amount evaluation element is exactly the same as the operation principle of the first embodiment, but the transparent conductive substrate 31 needs to be grounded through an apparatus jig.
Moreover, it is preferable that the transparent conductive substrate 31 is grounded when measuring the refractive index.

  Thus, in Example 2 of the present invention, since the transparent conductive substrate 31 itself is used as a transparent electrode whose potential does not change, the configuration is simplified and the film formation step of the transparent electrode is not necessary. .

Next, with reference to FIGS. 7 and 8, the charge amount evaluation element of Example 3 of the present invention will be described.
See FIG.
First, after a transparent electrode 42 made of an ITO film having a thickness of, for example, 1 μm is formed on the surface of a glass substrate 41 which is a transparent substrate, a polyimide resin is applied by a printing method, and then baked. Finally, by performing an alignment process by rubbing, an alignment film 43 having a thickness of, for example, 0.1 μm is formed.

Next, a sealing material 44 made of, for example, an epoxy resin and having a height of, for example, 5 μm is applied in the vicinity of the outer periphery of the substrate on the alignment film 43, and the liquid crystal injection port 45 is opened.
As described above, the height of the sealing material 44 is set to 5 μm, so that the thickness of the liquid crystal layer is set to 5 μm. If necessary to keep the film thickness uniform, a spacer (not shown) is provided on the alignment film 43. ) May be arranged.

  Next, a transparent glass substrate 46 on which the alignment film 47 is formed by the same method is prepared, and the glass substrate 41 and the glass substrate 46 are aligned so that the alignment film 43 and the alignment film 47 face each other and the alignment directions are orthogonal to each other. Paste together.

See FIG.
Next, an ITO film of 0.5 μm, for example, is formed on the glass substrate 46 by vapor deposition, and then isolated transparent of, for example, 200 μm × 200 μm by dry etching by reactive ion etching using a resist pattern (not shown) as a mask. An electrode 48 is formed.

  Next, the liquid crystal 49 is injected into the space between the alignment film 43 and the alignment film 47 from the liquid crystal injection port 45 by, for example, a vacuum injection method, and then sealed with a sealing material 50 made of, for example, an epoxy resin. Thus, the basic configuration of the charge amount evaluation element of Example 3 of the present invention is completed.

Next, the operation of the charge amount evaluation element of Example 3 of the present invention will be described.
When this charge amount evaluation element is carried into an electronic device manufacturing apparatus such as a plasma apparatus, charges generated during the process or handling are accumulated in the isolated transparent electrode 48, whereas the transparent electrode 42 is made of insulating glass. Since it is protected by the substrate 46 and the like, the charge state does not change from before being carried into the apparatus, and an electric field corresponding to the amount of charge accumulated in the isolated transparent electrode 48 is applied to the liquid crystal 49, so that the alignment state of the liquid crystal 49 is changed. Change.

After carrying out this charge amount evaluation element from the manufacturing apparatus, the charge amount of the isolated transparent electrode 48 is quantitatively evaluated by measuring the change in the alignment state of the liquid crystal 49 using the measurement system shown in FIG. be able to.
Further, the accumulated charge can be released by bringing the isolated transparent electrode 48 into contact with the ground terminal or the like, so that it can be used for the charge amount evaluation again.

  As described above, the charge amount evaluation element according to the third embodiment of the present invention can evaluate the charge amount evaluation element of the wafer to be processed in the electronic device manufacturing apparatus quantitatively with high spatial resolution, and can be reused. Because it is possible, running costs can be reduced.

Similar to a commercially available liquid crystal display, a polarizing filter in which the polarization direction is perpendicular may be formed on both surfaces of the liquid crystal. In this case, the refractive index change amount measuring system is changed from the system shown in FIG. , 23 is omitted.
Further, in the case of a configuration using such a polarizing filter, it is possible to perform qualitative evaluation with the naked eye, for example, evaluation of in-plane bias of the charge amount without using a measurement system.

Next, with reference to FIG. 9, the charge amount evaluation element of Example 4 of the present invention will be described. The charge amount evaluation element is the same as that of Example 3 except that the liquid crystal used is cholesteric liquid crystal. As there are, only the final structure is illustrated.
See FIG.
FIG. 9 is a conceptual cross-sectional view of the charge amount evaluation element according to the fourth embodiment of the present invention. As a liquid crystal injected into a facing space between the alignment film 43 and the alignment film 47, for example, a helical pitch is 0.1 μm. A short pitch cholesteric liquid crystal 51 is used.

Next, the operation of the charge amount evaluation element of Example 4 will be described.
When this charge amount evaluation element is carried into an electronic device manufacturing apparatus such as a plasma apparatus, charges generated during the process or handling are accumulated in the isolated transparent electrode 48, whereas the transparent electrode 42 is made of insulating glass. Since it is protected by the substrate 46 and the like, the charge state does not change from before being carried into the apparatus, and an electric field corresponding to the amount of charge accumulated in the isolated transparent electrode 48 is applied to the cholesteric liquid crystal 51. The state changes.

  After carrying out the charge amount evaluation element from the manufacturing apparatus, the change in the alignment state of the cholesteric liquid crystal 51 is measured by the measurement system shown in FIG. 5 to quantitatively evaluate the charge amount of the isolated transparent electrode 48. can do.

  The cholesteric liquid crystal 51 has a memory property, and liquid crystal molecules whose alignment state is changed from planar alignment to focal conic alignment by a weak electric field are maintained in the isolated transparent electrode 48 because the alignment state is maintained even when the electric field is removed. Since the charge amount can be evaluated even after the generated charge has escaped, the orientation state representing the charge amount associated with the process is maintained even if the isolated transparent electrode 48 contacts any conductive member during the carry-out operation.

  In addition, after applying a strong electric field to the charge amount evaluation element after the charge amount evaluation, the alignment state of the cholesteric liquid crystal 51 can be returned to the initial planar alignment by removing the electric field. Can be reused, and the running cost can be reduced.

Next, with reference to FIG. 10 and FIG. 11, the charge amount evaluation element of Example 5 of the present invention will be described, but the transparent electrode in the charge amount evaluation element of Example 1 is replaced with a reflective electrode. Accordingly, the measurement system is a reflection measurement system.
See FIG.
FIG. 10 is a configuration explanatory view of the charge amount evaluation element of Example 5 of the present invention. In the manufacturing process itself, the transparent electrode 12 made of the ITO film in Example 1 was replaced with the reflective electrode 19 made of the Al film. Except for this, it is exactly the same as Example 1.
In addition, although the figure has shown the case where 100 charge amount evaluation parts are arranged on the transparent insulating substrate 11, the number of arrangement is arbitrary.

Next, with reference to FIG. 11, a charge amount evaluation method using the charge amount evaluation element of Example 5 of the present invention will be described.
See FIG.
FIG. 11 is a configuration explanatory diagram of a refractive index change measurement system for evaluating the charge amount. Crossed Nicols through the beam splitter 25 with respect to the laser light source 21, the polarizing plate 22, the beam splitter 25, and the polarizing plate 22. The charge amount evaluation element 20 is installed at a position where the laser light is transmitted through the beam splitter 25, and the reflected light from the charge amount evaluation element 20 is reflected by the beam splitter 25. Then, the change in the refractive index of the electro-optic effect film 14 constituting the charge amount evaluation element 20 is measured as the change in the light intensity by measuring with the photodetector 24 through the polarizing plate 23 after being reflected by.

  When this charge amount evaluation element 20 is carried into an electronic device manufacturing apparatus such as a plasma apparatus, charges generated during the process are accumulated in the isolated transparent electrode 18, whereas the reflective electrode 19 is protected by the insulating protective film 16. Therefore, since the charge state does not change before being carried into the apparatus, an electric field is applied to the electro-optic effect film 14 in accordance with the amount of charge accumulated in the isolated transparent electrode 18, so that the refractive index changes.

After the charge amount evaluation element 20 is carried out of the apparatus, the charge amount evaluation element 20 is installed at a position where the laser beam of the measurement system shown in FIG. 11 is transmitted through the beam splitter 25, and the change in the refractive index is measured. The charge amount of the isolated transparent electrode 18 can be quantitatively evaluated.
Note that the reflective electrode 19 is preferably grounded when measuring the refractive index.

  Further, after the charge amount is evaluated, the charge of the charge amount evaluation element is returned to the initial state by releasing the accumulated charge by bringing the isolated transparent electrode 18 into contact with the ground terminal. Can be used for

  Thus, even with the charge amount evaluation element of Example 5 of the present invention, the charge amount of the wafer to be processed in the electronic device manufacturing apparatus can be evaluated nondestructively quantitatively with high spatial resolution, Since it can be reused, the running cost can be reduced.

Further, since the reflected light is detected, it is not necessary to consider light absorption by the substrate.
In this case as well, the range of charge amount that can be evaluated can be adjusted by the film thickness of the electro-optic effect film 14, and the spatial resolution can also be changed by the size of the isolated transparent electrode 18.

The embodiments of the present invention have been described above. However, the present invention is not limited to the configurations, manufacturing methods, conditions, and the like described in the embodiments, and various modifications can be made. For example, in each embodiment, the isolated transparent electrode is made of ITO, but is not limited to ITO. For example, zinc oxide (ZnO), tin oxide (SnO ₂ ), indium oxide (In ₂ O ₃ ) Other transparent conductive materials such as may be used.

Further, the film formation method of the transparent electrode is not limited to the vapor deposition method, and other film formation methods such as a sputtering method may be used.
Although reactive ion etching is used as an etching method for ITO, it is not limited to reactive ion etching. For example, wet etching using a mixed acid of hydrochloric acid and nitric acid or the like may be used.

In Example 1 or Example 2, PLZT is used as the electro-optic effect film, but is not limited to PLZT. For example, lead zirconate titanate (PZT), lithium niobate (LiNbO ₃ ) Other ferroelectrics such as lithium tantalate (LiTaO ₃ ) and potassium tantalate niobate (KTN) may also be used.

  Further, in the above-described Example 1, Example 2, or Example 5, the size of the isolated transparent electrode and the electro-optic effect film is the same, but it is not necessarily the same and may be different. It is desirable that the isolated transparent electrode is larger than the electro-optic effect film. With such a configuration, the electro-optic effect film is not damaged by plasma or the like, so that the number of reuses can be increased.

  In Example 1, Example 2, or Example 5, the insulating protective film is polished until the surface of the electro-optic effect film is exposed, but the electro-optic effect film is completely insulating. In this case, the isolated transparent electrode may be smaller than the electro-optic effect film.

  In the above-described Example 1, Example 2, or Example 5, the electro-optic effect film is formed by the sputtering method or the sol-gel method, but the metal organic chemical vapor deposition method (MOCVD method) It may be formed by an aerosol deposition method.

  In Example 1, Example 2, or Example 5 described above, an isolated transparent electrode and an electro-optic effect film are formed on the entire surface and then processed into an appropriate size by etching. It may be formed by using a method, thereby eliminating the need for a photoetching step.

  In each of the above embodiments, the size of the isolated transparent electrode is a square of 200 μm × 200 μm, but the shape and size are arbitrary, and can be appropriately changed according to the charge amount to be detected and the inspection environment. It is.

  In Example 4 above, the change in refractive index is measured by the same refractive index measurement system as in Example 3. However, unlike ordinary liquid crystals, the transmittance of cholesteric liquid crystals changes depending on the electric field. The measurement system may be evaluated with a simpler laser light source and light detector than the measurement system.

  In Example 5 above, a reflective electrode made of an Al film is provided on a transparent insulating substrate such as glass, but is not limited to an Al film, and is not limited to an Ag film, an Au film, a Pt film, or A conductive film having excellent reflectivity such as a Ti film may be used.

  In the case of such a reflection type charge amount evaluation element, the substrate does not need to be transparent, and a reflective conductive substrate such as an Al substrate is used as the substrate so as to correspond to the configuration of the second embodiment. By using it, it becomes unnecessary to provide a reflective electrode.

  In addition, a reflective charge amount evaluation element may be formed using liquid crystal so as to correspond to the above-described Example 3 or Example 4. In this case, an Al film is used instead of the transparent electrode 42. What is necessary is just to provide the reflective electrode which consists of.

Here, referring to FIG. 1 again, the detailed features of the present invention will be described again.
Again see Figure 1
(Supplementary Note 1) A charge amount evaluation element that quantitatively evaluates the total amount of charge accumulated on the surface of a substrate to be processed, wherein the substrate 1 has at least a surface having conductivity, and is disposed on the substrate 1 and is electro-optic. An effect film 5, an isolated transparent electrode 6 disposed on the electro-optic effect film 5, and an insulating protective film 7 that covers a region of the transparent substrate 1 that does not overlap projection with the electro-optic effect film 5. A charge amount evaluation element comprising a charge amount evaluation unit 4.
(Additional remark 2) The said base | substrate 1 has optical transparency, The charging amount evaluation element of Additional remark 1 characterized by the above-mentioned.
(Additional remark 3) The said base | substrate 1 is comprised from the transparent insulating substrate 2 and the transparent electrode 3 provided on the said transparent insulating substrate 2, The charge amount evaluation element of Additional remark 2 characterized by the above-mentioned.
(Additional remark 4) The said base | substrate 1 is comprised from a transparent conductive substrate, The charge amount evaluation element of Additional remark 2 characterized by the above-mentioned.
(Additional remark 5) The said base | substrate 1 is comprised from the insulated substrate and the reflective electrode provided on the said insulated substrate, The charge amount evaluation element of Additional remark 1 characterized by the above-mentioned.
(Additional remark 6) The said base | substrate is comprised from a reflective conductive substrate, The charge amount evaluation element of Additional remark 1 characterized by the above-mentioned.
(Supplementary note 7) The charge amount evaluation element according to any one of supplementary notes 1 to 6, wherein the electro-optic effect film 5 is a ferroelectric film whose refractive index changes with voltage.
(Additional remark 8) The said electro-optic effect film | membrane 5 is a liquid crystal, The charge amount evaluation element of any one of Additional remark 1 thru | or 6 characterized by the above-mentioned.
(Supplementary note 9) The charge amount evaluation element according to supplementary note 8, wherein the liquid crystal is a cholesteric liquid crystal.
(Additional remark 10) The charge amount evaluation element according to any one of Additional remarks 1 to 9, wherein a plurality of the charge amount evaluation sections 4 are provided on the same base body 1.

  As an application example of the present invention, evaluation of the charge amount in the manufacturing process of a magnetic disk head is typical. However, the invention is not limited to the manufacturing process of a magnetic disk head, and is not limited to a semiconductor, ferroelectric device, or super The present invention is also applied to the evaluation of the charge amount in the manufacturing process of the conductive device.

It is explanatory drawing of the fundamental structure of this invention. It is explanatory drawing of the manufacturing process to the middle of the charge amount evaluation element of Example 1 of this invention. It is explanatory drawing of the manufacturing process after FIG. 2 of the charge amount evaluation element of Example 1 of this invention. It is a structure explanatory drawing of the charge amount evaluation element of Example 1 of this invention. It is a configuration explanatory view of a refractive index change measurement system for evaluating the charge amount. It is explanatory drawing of the manufacturing process of the charge amount evaluation element of Example 2 of this invention. It is explanatory drawing of the manufacturing process to the middle of the charge amount evaluation element of Example 3 of the present invention. It is explanatory drawing of the manufacturing process after FIG. 7 of the charge amount evaluation element of Example 3 of this invention. It is a notional cross-sectional view of the charge amount evaluation element of Example 4 of the present invention. It is a structure explanatory drawing of the charge amount evaluation element of Example 5 of this invention. It is structure explanatory drawing of the measuring system of the refractive index change for evaluating the charging amount in Example 5 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate 2 Transparent insulation substrate 3 Transparent electrode 4 Charge amount evaluation part 5 Electro-optic effect film 6 Isolated transparent electrode 7 Insulating protective film 10 Charge amount evaluation element 11 Transparent insulation substrate 12 Transparent electrode 13 PLZT film 14 Electro-optic effect film 15 SiO _Two films 16 Insulating protective film 17 ITO film 18 Isolated transparent electrode 19 Reflective electrode 20 Charge amount evaluation element 21 Laser light source 22, 23 Polarizing plate 24 Photo detector 25 Beam splitter 31 Transparent conductive substrate 32 Electro-optic effect film 33 Insulating Protective film 34 Isolated transparent electrode 41 Glass substrate 42 Transparent electrode 43 Alignment film 44 Sealing material 45 Liquid crystal inlet 46 Glass substrate 47 Alignment film 48 Isolated transparent electrode 49 Liquid crystal 50 Sealing material 51 Cholesteric liquid crystal

Claims (5)

A charge amount evaluation element that quantitatively evaluates the total amount of charges accumulated on the surface of a substrate to be processed, the substrate having at least a conductive surface, an electro-optic effect film disposed on the substrate, and the electric A charge amount evaluation unit comprising: an isolated transparent electrode disposed on an optical effect film; and an insulating protective film that covers a region of the substrate that does not overlap projection with the electro-optical effect film. Quantity evaluation element. 2. The charge amount evaluation element according to claim 1, wherein the substrate is optically transmissive. 3. The charge amount evaluation element according to claim 1, wherein the electro-optic effect film is a ferroelectric film whose refractive index changes with voltage. 3. The charge amount evaluation element according to claim 1, wherein the electro-optic effect film is a liquid crystal. 5. The charge amount evaluation element according to claim 1, wherein a plurality of the charge amount evaluation units are provided on the same base.

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