KR20010093678A - Eddy current loss measurement sensor, film thickness measurement device and method thereof, and storage medium - Google Patents

Abstract

PURPOSE: A turbulence loss measuring sensor, apparatus and method for measurement of film thickness and recording medium is provided to measure a film thickness locally, while measuring the film thickness at high speed and with high accuracy. CONSTITUTION: A film thickness measuring apparatus(1) comprises a turbulence loss measuring sensor(20) wherein a first coil which receives a high-frequency current so as to excite a high-frequency magnetic field and which excites a turbulence in a conductive film(9) is included and a second coil which outputs the high-frequency current influenced by a turbulence loss caused by the turbulence is included, an impedance analyzer(48) which measures a change in the impedance of the sensor on the basis of the high-frequency current to be output by the second coil, a change in the current value of the high-frequency current or a change in the phase of the high-frequency current so as to measure the amount of the turbulence loss and a control computer including a film thickness computing part(54) which calculates the film thickness of the conductive film on the basis of the measured result of the impedance analyzer and on the basis of the measured result of an optical displacement sensor(32). An opening in which a third coil is exposed is formed in the bottom part of a ferrite which wraps the third coil.

Description

Eddy Current Loss Measurement Sensors, Film Thickness Measurement Devices, Film Thickness Measurement Methods and Recording Media {EDDY CURRENT LOSS MEASUREMENT SENSOR, FILM THICKNESS MEASUREMENT DEVICE AND METHOD THEREOF, AND STORAGE MEDIUM}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring film thickness. In particular, in the manufacturing process of a semiconductor integrated circuit device, an eddy current loss caused by an eddy current excited by exciting a high frequency magnetic field and excited to a conductive film on the wafer surface is measured. An eddy current measuring sensor and a measuring device and a computer readable recording medium for measuring a film thickness of the conductive film on a non-contact basis based on the measured eddy current loss.

The method of measuring the film thickness of a conductive film using an eddy current is effective as a non-contact and non-destructive film thickness measuring technique.

In the film thickness measurement method using the eddy current, the distance between the coil (sensor) generating the magnetic field and the conductive film greatly affects the amount of eddy current loss in the conductive film. For this reason, it becomes important to control the distance between a sensor and a conductive film with high precision.

Fig. 23 is data of one experimental example in which the amount of eddy current loss was measured as a change in inductance and resistance of a sensor. It can be seen from FIG. 23 that the inductance and resistance of the sensor change with the distance between the sensor and the conductive film.

In order to reduce the measurement error by such distance dependence and to improve the measurement accuracy, the following technique is proposed.

For example, as a first method, as shown in FIG. 23, the correlation between the distance between the sensor and the conductive film and the measured value is obtained in advance, and the distance between the sensor and the conductive film is changed to change the number of points. After the measurement, there is a method for correcting each measurement point using the correlation.

As a second method, as shown in FIG. 24, coils 103a and 103b for exciting eddy currents are provided opposite to the front and back of the conductive film 101 as the measurement target, and these coils 103a and 103b are provided. There is a method of measuring the Q of the inductance obtained by connecting in series with the impedance analyzer 104.

However, according to the second measuring method described above, there is a disadvantage that the configuration of the apparatus is complicated and the size is large.

In addition, in the first method of measuring the plural points by changing the distance, the sensor or the stage must be operated only for the number of measurement times, and data processing must be performed for each measurement point, so that considerable measurement time is required. Therefore, there is a problem that it is insufficient in practicality because it is unsuitable for high-speed measurement required in mass production lines or real-time measurement in the film thickness film forming process.

On the other hand, in order to enable local film thickness measurement and improve measurement accuracy, an attempt to concentrate the magnetic field generated by the coil at one point is shown in FIG. 25 as well as a method of improving the resolution by reducing the coil diameter. Only the method of inserting the ferrite or magnetic material core 110 into the coil 108 has been used.

As a sensor which measures the displacement of a metal lead, the sensor which concentrates a magnetic field on a lead is proposed. An example thereof will be described with reference to FIG. 26.

As shown in FIG. 26A, the displacement sensor shown in FIG. 26 includes a receiving coil 112 wound around the ferrite core 111 and a high frequency excitation coil wound around the receiving coil 112. 113 and an outer shield plate 114 having an upper side formed of a copper material installed to cover the ferrite core 111 and the coils 112 and 113.

The high frequency excitation coil 113 receives a high frequency current, generates a magnetic field, and excites an eddy current to the metal lead C to be measured. The receiving coil 112 receives a magnetic field whose magnetic flux density is reduced by the eddy current generated in the metal lead C. FIG.

The outer shield plate 114 is constituted by semi-cylindrical portions 114a and 114b which are disposed to face each other. As shown in FIG. 26B, each semi-cylindrical portion is a semicircular bottom plate half portion 114c and 114d. Has The left and right semi-cylindrical portions 114a and 114b are disposed to face each other via a minute gap, and as shown in the bottom view of FIG. 26C, the radial direction between the bottom half portions 114c and 114d of each bottom plate. The insulating slit 115 is formed. In this way, the outer shielding plate 114 is divided into left and right by the insulating slit 115 and is composed of each half insulated from each other. Although a linear insulating slit is shown in this example, a cross-shaped insulating slit may be formed.

When a high frequency excitation current is conducted to the high frequency excitation coil 113, a high frequency magnetic field is generated, and eddy currents are induced in the bottom half portions 114c and 114d on the left and right sides of the outer shield plate 114. Since the eddy currents are generated in the direction of disturbing the magnetic field, the composite magnetic field between the magnetic field by the excitation coil 113 and the magnetic field due to the eddy currents of the respective bottom plate halves 114c and 114d is the half plate 114c and 114d of the bottom plate. ), The magnetic flux density is small, and the magnetic flux density is large in the insulating slit 115. For this reason, as shown to (d) of FIG. 26, the sensor head is comprised with the nonuniform high frequency magnetic field whose magnetic flux density becomes the maximum value Bmax in insulation slit part S0. Therefore, as shown in Fig. 26A, when the sensor head is disposed above the metal lead C such as copper wire, if there is a lead C directly under the insulating slit 115 of the outer shield plate 114, The magnetic flux density of the space occupied by the lead wire C is the largest, and the shielding effect of the outer shield plate 114 is weakest with respect to the alternating magnetic field induced by the eddy current of the lead wire C. At this time, the impedance of the receiving coil 112 of the sensor head The influence of the lead C on the most will be greatest.

In this way, the structure of outputting the magnetic flux in the longitudinal length region by the linear or cross-shaped slit is effective for examining the displacement of an elongated object such as a metal lead wire, but when used for local film thickness measurement, It was insufficient because it was necessary to form a magnetic field as a spot.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides an eddy current loss measuring sensor that enables local film thickness measurement, a film thickness measuring device for measuring film thickness at high speed and with high accuracy, and a computer readable recording medium. There is a purpose.

1 is a cross-sectional view and a bottom view schematically showing the configuration of a first embodiment of an eddy current loss measuring sensor according to the present invention;

2 is a graph obtained by simulation of distribution of magnetic flux density generated from an eddy current sensor.

3 is a cross-sectional view and a bottom view schematically showing the configuration of a second embodiment of an eddy current loss measuring sensor according to the present invention;

4 is a block diagram schematically showing a configuration of a first embodiment of a film thickness measurement apparatus according to the present invention.

Fig. 5 is a graph showing experimental data in which the relationship between the distance between the eddy current sensor and the conductive film and the change in inductance and resistance of the eddy current sensor are measured.

Fig. 6 is a graph showing experimental data in which the relationship between the change in the film thickness of the conductive film and the change in inductance and resistance of the eddy current sensor is measured.

7 is a graph illustrating a method of correcting a measurement error of a film thickness.

8 is a graph showing experimental data obtained by measuring the relationship between the film thickness and the resolution of a measurement device as a parameter of the frequency of a high frequency current.

9 is a graph showing experimental data obtained by measuring changes in inductance and resistance values of an eddy current loss measuring sensor when the film thickness of the conductive film is changed.

10 is a cross-sectional view schematically showing a method of measuring a conductive film formed on a circuit pattern or a basic conductive film containing a conductive material by the film thickness measuring apparatus shown in FIG. 4.

11 is a block diagram schematically showing the configuration of a second embodiment of a film thickness measurement apparatus according to the present invention.

It is sectional drawing which shows schematically the structure of the eddy current loss measuring sensor with which 3rd Embodiment of the film thickness measuring apparatus which concerns on this invention is equipped.

It is a schematic diagram which shows the principal part of 4th Embodiment of the film thickness measuring apparatus which concerns on this invention.

It is a schematic diagram which shows the principal part of 5th Embodiment of the film thickness measuring apparatus which concerns on this invention.

Fig. 15 is a block diagram schematically showing the configuration of a sixth embodiment of a film thickness measurement apparatus according to the present invention.

16 is a cross-sectional view and a bottom view showing a specific configuration of an eddy current loss measuring sensor unit included in the film thickness measuring apparatus shown in FIG. 15.

17 is a graph for explaining a film thickness measuring method using the film thickness measuring apparatus shown in FIG. 15.

18 is a schematic view showing the main parts of a seventh embodiment of a film thickness measurement apparatus according to the present invention.

Fig. 19 is a block diagram schematically showing the configuration of an eighth embodiment of a film thickness measurement apparatus according to the present invention.

20 is a cross-sectional view and a bottom view showing a specific configuration of the eddy current loss measurement sensor unit shown in FIG. 19.

21 is a cross-sectional view and a bottom view showing a specific configuration of an eddy current loss measuring sensor unit included in a ninth embodiment of the film thickness measuring apparatus according to the present invention.

It is a schematic diagram which shows the principal part of 10th Embodiment of the film thickness measuring apparatus which concerns on this invention.

It is a graph explaining an example of the film thickness measuring method by a prior art.

It is a block diagram explaining another example of the film thickness measuring method by a prior art.

25 is a cross-sectional view and a bottom view showing an example of an eddy current sensor according to the prior art.

Explanatory drawing which shows an example of the displacement sensor by a prior art.

<Explanation of symbols for the main parts of the drawings>

1 to 4, 4 ', 4' ', 5, 5', 6, 6 ', 6' ': film thickness measuring device

8: semiconductor wafer (substrate)

9: conductive film

10, 20, 30, 120: Eddy current loss measuring sensor

12: excitation receiving integrated coil

14 ferrite (lack of investment)

15: Magnetic material plating

16: opening

19: basic circuit pattern or basic conductive film

22: receiving coil

24: Eddy Current Excitation Coil

32: optical displacement sensor

34, 35: Z stage

36: X-Y-Z stage

38: stage driving unit

42: control computer

44: high frequency power supply

46: optical displacement sensor controller

48, 49: Impedance Analyzer

52: memory

54 film thickness calculation unit

58: laser displacement sensor controller

60, 70, 70 ': Eddy Current Loss Measurement Sensor Unit

63: laser displacement sensor

68: excitation receiving integrated coil (air core coil)

72, 74: capacitive displacement sensor electrode

88: capacitive displacement sensor

This invention solves the said subject by the following means.

That is, according to the first embodiment of the present invention, the high frequency magnetic field is received to excite the high frequency magnetic field to excite the eddy current to the conductive film to be measured, and the magnetic field generated by the eddy current and the synthesized magnetic field of the high frequency magnetic field are An excitation receiving integral coil to receive, a first permeable member formed of a first permeable material and inserted into the excitation receiving integral coil to form a core, a second permeable material and the first permeable member and the An eddy current loss measuring sensor is provided that surrounds the excitation receiving integral coil and has a second permeable member whose opening is formed so as to expose at least a portion of the region of the excitation receiving integral coil on an opposite surface to the conductive film. .

The magnetic flux generated by the excitation receiving integral coil leaks outside only through the opening through the first permeable member, and then curves to return to the first permeable member via the second permeable member. Form a magnetic path. In addition, the magnetic flux is prevented from leaking to the periphery outside the sensor by the second permeable member. Thereby, the curve can be made steep. Therefore, by placing the eddy current loss measuring sensor close to the conductive film so that the peak of the curve is located in the conductive film, the eddy current can be excited only in a very small region. As a result, since the amount of eddy current loss can be measured in the local region, a highly accurate eddy current loss measuring sensor that does not destroy the measurement object and does not interfere with the film forming process, etching process or polishing process of the conductive film, Is provided.

Further, according to the second embodiment of the present invention, an eddy current excitation coil for receiving a high frequency current to excite a high frequency magnetic field to excite the eddy current to the conductive film to be measured, and to be wound by the eddy current excitation coil in the eddy current excitation coil. A receiving coil configured to receive a composite magnetic field between the magnetic field generated by the eddy current and the high frequency magnetic field, a first permeable material, and inserted into the receiving coil to form a core; It is formed of a second permeable material and is provided to surround the first permeable member, the receiving coil, and the eddy current excitation coil, and an opening to expose at least a portion of the receiving coil at an opposing surface of the conductive film. An eddy current loss measuring sensor is provided having a second permeable member on which is formed.

Thus, by providing the eddy current excitation coil and the receiving coil, an eddy current loss measuring sensor having better resolution is provided.

The opening is provided with a distance from the first permeable member so that magnetic flux is emitted only to a local region of the conductive film.

In the eddy current loss measuring sensor described above, it is preferable that the surface portion of the opening or the surface portion of the opening and the vicinity of the opening is formed using a third permeable material having a higher permeability than the second permeable material. This makes it possible to concentrate the magnetic flux emitted from the opening in a more localized region.

Preferably, the first to third permeable materials include an electrically insulating material, and the electrically insulating material includes ferrite.

According to the third embodiment of the present invention, the high frequency current is received to excite the high frequency magnetic field to excite the eddy current to the conductive film to be measured, and output the high frequency current affected by the eddy current loss caused by the eddy current. Detecting the eddy current loss measuring sensor and the high frequency current output from the eddy current loss measuring sensor, and measuring a change in impedance of the eddy current loss measuring sensor, a change in current value of the high frequency current, or a change in phase of the high frequency current. Eddy current loss measuring means for outputting as data representing the magnitude of the eddy current loss, distance measuring means for measuring a distance between the conductive film and the eddy current loss measuring sensor, measurement results of the eddy current loss measuring means and the distance measuring means. Based on the measurement result of the film thickness of the conductive film Shipping is provided a thickness measuring apparatus for a film having a thickness calculation means.

The distance measuring means measures the distance between the conductive film and the eddy current loss measuring sensor, and changes the measured distance and impedance of the eddy current loss measuring sensor, change of the current value of the high frequency current, or phase of the high frequency current. Based on the change in, the film thickness calculating means calculates the film thickness of the conductive film. Accordingly, a non-contact nondestructive film thickness measuring apparatus for measuring film thickness with high precision is provided.

The frequency of the high frequency current is preferably about 1 MHz to about 10 MHz.

In the above-described film thickness measuring apparatus, the eddy current loss measuring sensor receives the high frequency current to excite the high frequency magnetic field to excite the eddy current to the conductive film to be measured, and at the same time, the magnetic field generated by the eddy current and the high frequency magnetic field; An excitation receiving integral coil which receives a composite magnetic field of the output and outputs the high frequency current affected by the eddy current loss due to the eddy current, and a first formed of a first permeable material and inserted into the excitation receiving integral coil to form a core It is preferable to have a permeable member and a second permeable member formed of a second permeable material and provided to surround the first permeable member and the excitation receiving integrated coil.

In addition, the eddy current loss measurement sensor is provided so as to receive the high frequency current to excite the high frequency magnetic field to excite the eddy current to the conductive film to be measured, and to be wound by the eddy current excitation coil in the eddy current excitation coil. And a receiving coil for receiving a composite magnetic field generated by the eddy current and the high frequency magnetic field and outputting the high frequency current affected by the eddy current loss due to the eddy current, and a first permeable material. A first permeable member inserted into the receiving coil to form a core, and a second permeable member formed of a second permeable material and provided to surround the first permeable member, the receiving coil, and the eddy current excitation coil. You may have.

It is preferable that the second high permeability member has an opening formed so as to expose the excitation receiving integrated coil or at least a portion of the receiving coil at a surface opposite to the conductive film.

When the opening is formed in the second permeable member, the film thickness of the conductive film can be measured locally. Thereby, even if it is a conductive film with large fluctuation | variation in film thickness, such as a conductive film formed on the board | substrate with a pattern, it can measure with high precision. This is particularly advantageous when monitoring the film thickness in parallel with the film forming process.

The opening may be formed by adjusting the distance to the first permeable member so that the magnetic flux is emitted only to the local region of the conductive film.

Moreover, the surface part of the said opening part, the surface part of the said opening part, and the surface part of the area | region near the opening may be formed using the 3rd permeable material with higher permeability than the said 2nd permeable material. This makes it possible to concentrate the magnetic flux emitted from the opening in a more localized region.

In the eddy current loss measurement sensor included in the film thickness measuring apparatus, the first to third permeable materials include an electrical insulating material, and the electrical insulating material preferably includes ferrite.

The above-described film thickness measuring apparatus includes a change in the distance between the eddy current loss measuring sensor and the conductive film, the frequency of the high frequency current, the film thickness of the conductive film, the resistivity of the conductive film, and the impedance of the eddy current loss measuring sensor. Or the relationship between the distance, the frequency, the film thickness and the resistivity, and the change in the current value of the high frequency current, or the distance, the frequency, the film thickness and the resistivity, and the high frequency current Storage means for storing measurement data indicative of a correlation with a change in phase of said film thickness calculation means, wherein said film thickness calculating means includes a change in impedance of said measured eddy current loss measuring sensor, a change in current value of said high frequency current, Or by comparing the change of phase of the high frequency current with the measurement data. It is preferable to calculate.

The film thickness measuring apparatus further includes a stage for supporting a substrate on which the conductive film is formed on the surface, and a control means for controlling the relative positional relationship between the stage and the eddy current loss measuring sensor based on a measurement result of the distance measuring means. It is preferable to further provide.

By the control means, it becomes possible to keep the distance between the stage and the eddy current loss measuring sensor almost constant based on the measurement result of the distance measuring device.

The control means moves the eddy current loss measuring sensor to a region deviating from the influence of the eddy current, prior to excitation of the eddy current to the conductive film, and the eddy current loss measuring means measures the eddy current measured at a region deviating from the influence of the eddy current. Preferably, the impedance of the loss measuring sensor, the current value of the high frequency current, or the phase of the high frequency current is measured as a measurement reference value, and the film thickness calculating means corrects the calculated film thickness based on the measurement reference value.

By the above correction process, measurement errors due to external factors or internal factors can be appropriately corrected.

In the film thickness measuring apparatus, a reference conductive film, which is a measurement reference, is prepared in advance in a region outside the influence of the eddy current with a predetermined film thickness, and the control means prior to excitation of the eddy current to the conductive film as the measurement target, The eddy current loss measuring sensor is moved to a region where the reference conductive film is prepared, and the eddy current loss measuring means includes the impedance of the eddy current loss measuring sensor measured in the region where the reference conductive film is formed, the current value of the high frequency current, or the high frequency current. The phase of may be measured as a measurement reference value.

Further, the reference conductive film is a plurality of reference conductive films formed with different film thicknesses from conductive materials having different conductivity, the eddy current loss measuring means measures a plurality of measurement reference values, and the film thickness calculating means calculates the film More preferably, the thickness is corrected based on the plurality of measurement reference values.

The above-described film thickness measuring apparatus further includes stage moving means for moving the stage and sensor moving means for moving the eddy current loss measuring sensor, and the control means includes a film forming step, an etching step, or a polishing step of the conductive film. Parallel to the stage moving means or the sensor moving means or the stage moving means and the sensor moving means such that the eddy current loss measuring sensor scans the conductive film while maintaining a substantially constant mutual distance between the conductive films. It is desirable to control.

By the control means, the film thickness can be measured at high speed by scanning the eddy current loss measuring sensor.

In addition, the film thickness measuring apparatus according to the present invention further includes a stage moving means for moving the stage, wherein the control means includes an eddy current loss measuring sensor in parallel with a film forming process, an etching process or a polishing process of the conductive film. The stage moving means may be controlled so as to scan the conductive film, and the film thickness calculating means may receive the measurement result of the distance measuring means and correct the calculated film thickness value.

By receiving the measurement result of the distance measuring means and correcting the calculated film thickness value, there is no need to keep the distance constant during the measurement operation. Accordingly, the eddy current loss measuring sensor can be scanned on the conductive film at a higher speed in a film forming process and in real time.

The eddy current loss measurement sensor receives the high frequency current to excite the high frequency magnetic field to excite the eddy current to the conductive film to be measured, and receives the composite magnetic field generated by the eddy current and the high frequency magnetic field to receive the eddy current. And an excitation receiving integrated air core coil for outputting the high frequency current affected by the eddy current loss caused by the above, wherein the distance measuring means is provided above the air core coil, and generates a laser beam to generate the air core. The laser displacement sensor may be incident on the surface of the conductive film via the air core of the coil and receive the reflected light from the surface of the conductive film via the air core.

In addition, the eddy current loss measurement sensor is provided so as to receive the high frequency current to excite the high frequency magnetic field to excite the eddy current to the conductive film to be measured, and to be wound by the eddy current excitation coil in the eddy current excitation coil. And an air core receiving coil receiving a composite magnetic field generated by the eddy current and the high frequency magnetic field and outputting the high frequency current affected by the eddy current loss due to the eddy current. A laser displacement sensor provided above the receiving coil, the laser displacement sensor generating laser light and incident the surface of the conductive film via the air core of the receiving coil, and receiving the reflected light from the surface of the conductive film via the air core; It may be.

The laser displacement sensor irradiates a laser beam onto the surface of the conductive film via the air core of the air core coil or the receiving coil, and receives the reflected light via the air core. It irradiates to the intersection of the centerline and the surface of the said electroconductive film, or its vicinity area | region. Therefore, the distance between the eddy current loss measurement sensor and the conductive film can be measured directly. As a result, the measurement of the distance and the measurement of the eddy current loss can be performed simultaneously.

In the above-described film thickness measuring apparatus, further comprising distance measuring error correction means for measuring the distance by driving the laser displacement sensor prior to measuring the film thickness of the conductive film, and correcting the measurement error with respect to the measurement result, The control means controls the stage movement means and the sensor movement means based on the measurement distance corrected by the distance measurement error correction means such that the eddy current loss measurement sensor scans the conductive film while maintaining a substantially constant mutual distance. It is desirable to control. Further, as compared with the eddy current loss measuring sensor scanning the conductive film while maintaining a substantially constant mutual distance, the film thickness calculating means corrects the calculated film thickness value by the distance measuring error correcting means. It may be corrected based on the measurement distance.

Since the distance measurement error correction means corrects the measurement error of the distance prior to the film thickness measurement, the conductive film formed on the LSI pattern and the conductive film having a large change in reflectance or the roughness of the surface with a small measurement score can be used. The measurement accuracy of the distance can be improved.

Further, in the film thickness measuring apparatus according to the present invention, the distance measuring means has an electrode provided in proximity to the eddy current loss measuring sensor, and measures the distance based on the capacitance between the electrode and the conductive film. It is preferable to include a capacitive displacement sensor.

Since the capacitive displacement sensor is not affected by the reflectance of the light on the surface of the conductive film or the roughness of the surface, the distance measuring means measures the distance between the eddy current loss measuring sensor and the conductive film with high accuracy. You can do it. In this case, the conductive film is held at ground potential. This is realized by connecting the side surface of the substrate on which the conductive film is formed to ground, or by connecting the surface or the back side of the region of the conductive film that does not affect the film thickness measurement to the ground.

The measuring electrode is preferably arranged such that its bottom face is substantially in the same plane as the bottom face of the eddy current loss measuring sensor. Thus, the distance can be measured directly.

In addition, the measurement electrode may be a thin film electrode formed of a high resistance material. Accordingly, the possibility of generating an eddy current in the measurement electrode itself can be reduced.

In addition, the measuring electrode has a ring shape for winding the eddy current loss measuring sensor, and an outer diameter of the measuring electrode is a diameter of a region where eddy current loss occurs due to the eddy current excited to the conductive film by the eddy current loss measuring sensor. Is substantially the same as, and the inner diameter of the measuring electrode is small enough that the eddy current excited in the measuring electrode by the eddy current loss measuring sensor is negligible in measurement, and that between the measuring electrode and the conductive film Preferably, the capacitance is selected to provide the measuring electrode with a surface area that is measurable. Accordingly, generation of the eddy current can be further avoided.

In the above-described film thickness measuring apparatus, the stage may be formed of an insulating material or a material having a conductivity such that only a negligible eddy current is generated by receiving the high frequency magnetic field and generating a negligible measurement. Thereby, since the eddy current loss which generate | occur | produces in a stage is suppressed largely, the precision of a measurement can be further improved.

It is preferable that the said film thickness measuring apparatus is further provided with the frequency control means which controls the frequency of the said high frequency current.

The depth of penetration of the eddy current into the conductive film changes depending on the frequency of the magnetic field that excites the eddy current. Therefore, the resolution of the apparatus can be increased by flexibly adjusting the frequency of the high frequency current in accordance with the expected value of the film thickness of the conductive film.

Moreover, when using the film thickness measuring apparatus which concerns on this invention in parallel with the film formation process of the said conductive film, the frequency of the said high frequency current can be adjusted suitably according to the change of film thickness. This makes it possible to scan the inside of the substrate surface at a higher speed and at the same time, to enable high-precision film thickness monitoring in real time.

Further, the conductive film is formed above a circuit pattern or a basic conductive film containing a conductive material, and the film thickness calculating means of the film thickness measuring device uses the film thickness value of the circuit pattern or the basic conductive film as an underlayer film thickness value. Calculating in advance, calculating the total film thickness value of the lower layer film thickness value and the film thickness value of the conductive film during or after the formation of the conductive film, and subtracting the lower layer film thickness value from the total film thickness value desirable. In this way, since the lower layer thickness value calculated in advance is subtracted from the total film thickness value, only the film thickness value can be accurately measured even when the conductive film to be measured is formed above the circuit pattern or the basic conductive film.

It is preferable that the above-mentioned film thickness measuring apparatus is equipped with a plurality of said eddy current loss measuring sensors.

By simultaneously controlling a plurality of eddy current loss measuring sensors and scanning in the plane of the conductive film on the substrate, the distribution of the film thickness can be measured at high speed.

The eddy current loss measuring sensor is provided on the side opposite to the surface on which the conductive film to be measured is formed, the surface to be etched, or the surface to be polished, and opposite to the surface on which the conductive film to be measured is formed. The case where it is provided facing a board | substrate surface, and the case where it is provided in the opposite surface to the board | substrate on the opposite side to the surface in which the said conductive film used as the measurement object is formed, and the surface in which the conductive film used as the measurement object is formed are included.

When the eddy current loss measuring sensor is provided opposite to the surface on which the conductive film to be measured is formed, the surface to be etched, or the surface opposite to the surface to be polished, the eddy current loss measurement sensor is used in the film formation process, the etching process or the polishing process. It is also possible to eliminate the possibility of disturbing the formation, etching or polishing of the conductive formation and to measure the eddy current loss measurement sensor by bringing the substrate surface into contact with the eddy current loss measurement sensor. In addition, in the CMP polishing step, it is not necessary to scan while avoiding contact with the polishing tool. As a result, measurement constraints are greatly reduced, and a film thickness measuring apparatus excellent in any of the degree of freedom in design and the throughput of measurement is provided.

Further, according to the fourth embodiment of the present invention, a film is provided with an eddy current loss measuring sensor and a distance measuring means for exciting a high frequency magnetic field to excite the eddy current to the conductive film to be measured and detecting the eddy current loss caused by the eddy current. A film thickness measuring method using a thickness measuring device, comprising: a distance measuring step of measuring a distance between the eddy current loss measuring sensor and the conductive film by the distance measuring means, and supplying a high frequency current to the eddy current loss measuring sensor, Excitation of the high frequency magnetic field to excite an eddy current to the conductive film to change the impedance of the eddy current loss measuring sensor from the high frequency current output from the eddy current loss measuring sensor, the change of the current value of the high frequency current, or the high frequency current. Eddy current loss measurement to measure changes in phase And the distance between the change in the impedance and the eddy current loss measuring sensor and the conductive film, or the distance between the change in the current value of the high frequency current and the eddy current loss measuring sensor and the conductive film, or the There is provided a film thickness measuring method comprising a film thickness calculating step of calculating a film thickness of the conductive film based on a change in phase of a high frequency current and the distance between the eddy current loss measuring sensor and the conductive film.

According to the film thickness measuring method, the change of the impedance and the distance between the eddy current loss measuring sensor and the conductive film, or the change of the current value of the high frequency current and the eddy current loss measuring sensor and the conductive film between Since the film thickness of the conductive film is calculated based on the distance or the change in phase of the high frequency current and the distance between the eddy current loss measuring sensor and the conductive film, high precision film thickness measurement is performed in the form of non-contact and non-destructive. It can be realized.

The distance measuring means includes an optical displacement sensor, and the film thickness measuring method includes a distance for measuring the distance by driving the optical displacement sensor before measuring the thickness of the conductive film, and correcting a measurement error with respect to the measurement result. A measurement error correction step is further provided, and the film thickness calculation step preferably includes a step of correcting the calculated film thickness value based on the measurement distance corrected by the distance measurement error correction step.

Since the distance measurement error correction step is further provided, even for a conductive film formed on the LSI pattern and having a large change in reflectance, or a conductive film with a high surface roughness, the measurement accuracy of the distance can be improved with a small measurement score. .

The eddy current measuring sensor includes an air core coil, and the distance measuring means is installed above the air core coil, generates laser light, enters the surface of the conductive film via the air core of the air core coil, and passes through the air core. And a laser displacement sensor for receiving the reflected light from the surface of the conductive film, wherein the distance measuring step and the eddy current loss measuring step are performed simultaneously in parallel.

Since the laser displacement sensor irradiates a laser beam to the surface of the conductive film via the air core of the air core coil and receives the reflected light via the air core, the laser light is the center line of the air core and the electroconductivity. Irradiate at or near the intersection with the surface of the film. Therefore, the distance between the eddy current loss measurement sensor and the conductive film can be measured directly. Thereby, the measurement accuracy of the said distance can be improved.

In addition, since the distance measuring step and the eddy current loss measuring step are performed simultaneously, the throughput of the film thickness measurement is greatly improved.

In the film thickness measuring method according to the present invention, the distance measuring means has a measuring electrode provided in proximity to the eddy current loss measuring sensor, and measures the distance based on the capacitance between the measuring electrode and the conductive film. Including capacitive displacement sensor,

It is preferable that the distance measuring process and the eddy current loss measuring process are executed simultaneously.

According to the measuring method, the distance can be measured with high accuracy because the electrostatically-displaced displacement sensor is not affected by the reflectance of the light on the surface of the conductive film or the roughness of the surface.

Prior to the eddy current loss measuring process, the high frequency current is supplied to the eddy current loss measuring sensor in a region deviating from the influence of the eddy current loss, and the impedance of the eddy current loss measuring sensor from the high frequency current output from the eddy current loss measuring sensor, And a reference value measuring step of measuring a current value of the high frequency current or a phase of the high frequency current as a measurement reference value, wherein the film thickness calculating step includes a change in impedance of the eddy current loss measuring sensor and a current value of the high frequency current. And a first calculation step of calculating a film thickness of the conductive film based on a change or a change in phase of the high frequency current, and a first correction step of correcting a value of the calculated film thickness based on the measurement reference value. desirable.

And a reference value measuring step of acquiring a measurement reference value in an area outside the influence of the eddy current loss, and wherein the film thickness measuring step includes a first correction step of correcting the calculated film thickness value based on the measurement reference. Therefore, it is possible to prevent fluctuations in measured values due to fluctuations in the apparatus and the like.

In the region deviating from the influence of the eddy current, a reference conductive film serving as a measurement reference is prepared in advance with a predetermined film thickness, and the reference value measuring step includes the impedance of the eddy current loss measuring sensor measured in the region where the reference conductive film is formed, and the high frequency. The step of measuring the current value of the current or the phase of the high frequency current as the measurement reference value may be used.

The reference conductive film may be a plurality of reference conductive films formed with different film thicknesses from conductive materials having different conductivity, and the reference value measuring step may also be a step of measuring the plurality of measurement reference values.

The film thickness measuring apparatus further includes a stage for supporting a substrate on which the conductive film is formed, and the eddy current loss measuring process is performed based on the measurement result of the distance measuring process, such that the stage and the eddy current are substantially constant. It is preferred to include a process of controlling the relative positional relationship with the loss measuring sensor. Further, instead of the step of controlling the relative positional relationship such that the distance is substantially constant, the film thickness calculating step is performed by changing the impedance of the eddy current loss measuring sensor, the change of the current value of the high frequency current, or the phase of the high frequency current. A first calculating step of calculating the film thickness of the conductive film based on the change of the relationship between the distance and the impedance, or the relationship between the distance and the current value of the high frequency current, or between the distance and the high frequency current. A second correction step of correcting the film thickness value obtained in the first calculation step may be included based on the relationship with the phase.

Further, the film thickness measuring apparatus is used in the film forming step, the etching step or the polishing step of the conductive film, and the film thickness measuring method is more preferably performed in parallel with the film forming step, the etching step or the polishing step.

In addition, the film thickness measuring method preferably further includes a step of controlling the frequency of the high frequency current so as to be a frequency according to a desired film thickness of the conductive film.

The conductive film is formed above a circuit pattern or a basic conductive film containing a conductive material, and the film thickness measuring method includes a step of previously calculating a film thickness value of the circuit pattern or the basic conductive film as an underlayer film thickness value; And calculating the total film thickness value of the lower layer film thickness value and the film thickness value of the conductive film during or after the formation of the conductive film, and subtracting the lower layer film thickness value from the calculated total film thickness value. More preferably.

Further, according to the fifth embodiment of the present invention, an eddy current loss measuring sensor for exciting the high frequency magnetic field to excite the eddy current to the conductive film to be measured and detecting the eddy current loss caused by the eddy current, the distance measuring means and the computer. A distance measuring procedure for measuring the distance between the eddy current loss measuring sensor and the conductive film by the distance measuring means, and the high frequency current is supplied to the eddy current loss measuring sensor. An eddy current excitation order for exciting a magnetic field to excite the eddy current to the conductive film, a change in impedance of the eddy current loss measuring sensor from the high frequency current output from the eddy current loss measuring sensor, a change in current value of the high frequency current, or the Eddy current loss to measure the change in phase of high frequency current The measurement order, the change of the impedance and the distance between the eddy current loss measuring sensor and the conductive film, or the change of the current value of the high frequency current and the distance between the eddy current loss measuring sensor and the conductive film, or And a film thickness calculating method for calculating the film thickness of the conductive film based on the change in phase of the high frequency current and the distance between the eddy current loss sensor and the conductive film. A computer readable recording medium having recorded thereon a program is provided.

The film thickness measuring method further includes a distance measurement error correction procedure for measuring the distance prior to the film thickness measurement of the conductive film and correcting a measurement error with respect to the measurement result, wherein the film thickness calculation order is calculated It is preferable to include a procedure of correcting the film thickness value based on the measurement distance corrected by the distance measurement error correction procedure.

In the film thickness measurement method, it is preferable that the distance measurement order and the eddy current loss measurement order be executed simultaneously.

The film thickness calculation order includes a first calculation procedure for calculating the film thickness of the conductive film based on a change in impedance of the eddy current loss measuring sensor, a change in current value of the high frequency current, or a change in phase of the high frequency current. A film thickness value obtained in the first calculation order based on the relationship between the distance and the impedance, or the relationship between the distance and the current value of the high frequency current, or the relationship between the distance and the phase of the high frequency current. It is preferable to include a second correction procedure for correcting.

EMBODIMENT OF THE INVENTION Hereinafter, some embodiment which concerns on this invention is described, referring drawings. In addition, in the following figures, the same code | symbol is attached | subjected to the same part, and the description is abbreviate | omitted suitably.

(1) Embodiment of Eddy Current Loss Measurement Sensor

First, some embodiments of the eddy current loss measuring sensor according to the present invention will be described.

(a) First Embodiment of Eddy Current Loss Measurement Sensor

FIG. 1A is a sectional view schematically showing a first embodiment of an eddy current loss measuring sensor according to the present invention, and FIG. 1B is a bottom view thereof.

As shown in FIG. 1A, the eddy current loss measuring sensor 10 of the present embodiment includes a cylindrical coil 12 and a ferrite core 14a (first) inserted into the coil 12. And a ferrite 14b to 14d (second permeable member) provided to surround the coil 12 and the ferrite core 14a.

The coil 12 is an excitation receiving integrated coil that receives a high frequency current from a high frequency power supply (not shown) to form a magnetic field and receives a magnetic field generated by an eddy current excited by the conductive film 9 as a measurement target. have.

The ferrite core 14a constituting the central axis and the surrounding ferrites 14b to 14d all have relatively high specific permeability, for example, 400.

The characteristic of the eddy current loss measuring sensor of the present embodiment is that the opening 16 is formed in the ferrite 14b located on the bottom surface of the ferrite 14, which is the opposite surface to the conductive film 9. The opening 16 is formed in the ferrite 14b so as to form a circular annular recess in the peripheral region of the ferrite core 14a, as shown in Fig. 1B, and at the bottom of the coil 12 The bottom surface is exposed. In addition, in the region near the opening 16 of the surface of the opening 16 and the surface areas of the ferrites 14a and 14b, the plating 15 is made of a high permeability material having a higher permeability than that of the ferrites 14a and 14b. This is being done. Accordingly, the magnetic flux NF1 can be concentrated and released only in the local region.

The operation of the eddy current loss measuring sensor 10 shown in FIG. 1 is as follows.

When a high frequency current is supplied to the coil 12, the magnetic flux line MF1 generated by the coil 12 passes through the central axis of the ferrite core 14a to reach the opening 16, and leaks to the outside only in the opening 16. Then, the abrupt parabola forming one vertex is drawn from the lower side of the coil 12 and returned into the ferrite 14b. Form a magnetic path that returns. Accordingly, the magnetic field distribution in the lateral direction of the eddy current loss measuring sensor 20 is suppressed to be very small, and a circular annular opening 16 is formed in the center region of the ferrite 14b at the bottom, and the opening 16 Since the magnetic material plating 15 is applied to the outer peripheral surface of the surface and the surface region of the ferrite 14b which winds up the opening 16, the magnetic flux leaks to the outside only from the opening 16.

Therefore, when the eddy current loss measurement sensor 10 is disposed close to the conductive film 9 so that the parabola drawn by the magnetic flux lines leaking from the opening 16 reaches the conductive film 9, the lower region of the coil 12 Only at eddy currents are locally excited. The amount of eddy current loss is measured locally by measuring the change of the impedance, the high frequency current value, or the high frequency current phase of the coil 12 which has received a composite magnetic field between the magnetic field generated by this eddy current and the magnetic field generated from the coil 12. You can do it.

FIG. 2 is a graph obtained by simulation of magnetic flux density distributed on the surface of the conductive film 9 when a high frequency current is supplied to the eddy current loss measuring sensor 10. In FIG. 2, the graph shown by the solid line is a simulation result in the case of using the eddy current loss measuring sensor 10, and the graph shown by the dotted line is a simulation result in the case of using an example of the eddy current loss measuring sensor by a prior art. . As can be seen from FIG. 2, according to the present embodiment, the magnetic flux density is concentrated and distributed in the area of the radius R of about 0.3 mm from the center of the sensor, and only in a very minute area compared with the prior art. It can be seen that it is distributed.

As described above, according to the eddy current loss measuring sensor 10 of the present embodiment, since the magnetic flux leaks to the outside only from the opening 16, a sufficient magnetic flux line is provided so that the opening 16 faces the conductive film 9. By disposing the distance passing through the conductive film 9 by, for example, 0.3 mm, the eddy current can be generated only in a very minute region in the conductive film 9. Since the synthesized magnetic field changes under the influence of such eddy current, the amount of eddy current loss can be measured with high accuracy by measuring the change of the impedance of the eddy current loss measuring sensor 10, the current value of the high frequency current, or the phase of the high frequency current.

(b) Second Embodiment of Eddy Current Loss Measurement Sensor

Next, a second embodiment of the eddy current loss measuring sensor according to the present invention will be described with reference to FIG. 3.

FIG. 3A is a sectional view schematically showing the eddy current loss measurement sensor 20 of the present embodiment, and FIG. 3B is a bottom view thereof. As can be seen in comparison with FIG. 1, the feature of the present embodiment is that the coil in the sensor has an eddy current excitation coil 24 and a receiving coil 22. The rest of the configuration is almost the same as the eddy current loss measuring sensor 10 described above. In addition, the operation | movement of the eddy current loss measuring sensor 20 of this embodiment is also substantially the same as that of 1st Embodiment mentioned above.

As described above, according to the present embodiment, since two coils each having separate functions for eddy current excitation and eddy current loss reception are used, an eddy current loss measuring sensor having better resolution is provided.

In the two embodiments described above, the ferrites 14b to 14d are configured to cover the ferrite core 14a and the coil 12 or the coils 22 and 24 except for the opening 16. The eddy current loss measurement sensor according to the present invention is not limited to the back side of the shape in which magnetic flux leaks to the outside from the opening 16 locally. For example, the magnetic material film may be attached only to the surfaces of the region under the coils of the ferrite core 14a and the ferrite 14b, and the magnetic material film may be attached only to the outer circumferential surface of the ferrite 14c. . In addition, although the ferrite material was used as the first and second permeable materials, it is not limited thereto, and other permeable materials may be used as long as the permeability is high. Also, even in the first and second permeable members, it is not necessary to have a uniform permeability ρ for all of them, and the magnetic field is prevented from leaking around the sensor, so that the conductive film 9 can leak magnetic flux only in a local region. Of course, as long as it can concentrate, a part or all of it can be substituted by the permeable material with higher permeability.

(2) Embodiment of the film thickness measuring apparatus

Next, some embodiments of the film thickness measuring apparatus according to the present invention will be described with reference to the drawings.

(a) First Embodiment of Film Thickness Measuring Apparatus

4 is a block diagram showing a schematic configuration of a first embodiment of a film thickness measuring apparatus according to the present invention. As shown in FIG. 4, the film thickness measuring apparatus 1 of this embodiment is XYZ stage 36, the above-mentioned eddy current loss measuring sensor 20, Z stage 34, stage drive part 38, and optical displacement. A sensor 32, an optical displacement sensor controller 46, a high frequency power supply 44, an impedance analyzer 48, and a control computer 42 for controlling the entire apparatus are provided.

The XYZ stage 36 mounts the semiconductor wafer 8 on which the conductive film 9 (refer to FIG. 1) which is the measurement object on the surface is mounted on the upper surface, receives the supply of the control signal from the stage driver 38, and arbitrarily selects the XYZ. The semiconductor wafer 8 is moved in the direction of. The XYZ stage 36 is made of an insulating material or a material with low conductivity, and generates no eddy current or negligible measurement even when receiving a high frequency magnetic field generated by the eddy current loss measuring sensor 20. Only eddy current is generated.

The optical displacement sensor 32 measures the distance between the eddy current loss measuring sensor 20 and the conductive film 9 in response to a control signal supplied from the optical displacement sensor controller 46, and measures the measured value by the optical displacement sensor controller. Supply to control computer 42 via 46. The optical displacement sensor 32 and the optical displacement sensor controller 46 constitute the distance measuring means in this embodiment.

The Z stage 34 suspends and supports the eddy current loss measurement sensor, and receives the supply of the control signal from the stage driver 38 to move the eddy current loss measurement sensor in the Z direction.

The stage driver 38 receives a command signal from the control computer 42 and supplies a control signal to the X-Y-Z stage 36 and the Z stage 34.

The high frequency power supply 44 supplies a high frequency current of a desired frequency to the eddy current excitation coil 24 (see FIG. 3) of the eddy current loss measuring sensor based on the command signal of the control computer 42. The frequency of the current is about 1 MHz to about 10 MHz in this embodiment.

The eddy current excitation coil 24 which has received the high frequency current forms a high frequency magnetic field, whereby the eddy current is locally generated in the conductive film 9. The receiving coil 22 receives a composite magnetic field between the magnetic field generated by the eddy current of the conductive film 9 and the magnetic field generated by the coil 24. The impedance analyzer 48 receives the receiving coil of the eddy current loss measuring sensor 20. (22) (refer to FIG. 3), the high frequency current for measurement is supplied to the receiving coil 22, and the change due to the eddy current loss effect in the impedance of the eddy current loss measuring sensor 20, and the high frequency current for measurement The change due to the eddy current loss effect in the current value or the change due to the eddy current loss effect in the phase of the measurement high frequency current is measured and the measurement result is supplied to the control computer 42.

The control computer 42 has a film thickness calculating section 54 and a memory 52.

The memory 52 stores a recipe file including a program of measurement order and data tables for measurement.

The measurement data includes the distance D _SF between the eddy current loss measurement sensor and the conductive film 9, the frequency f of the current supplied from the high frequency power supply 44, the film thickness t of the conductive film 9, and the thickness of the conductive film 9. The relationship between the change in the impedance of the eddy current loss measuring sensor affected by the eddy current loss, the change in the current value of the high frequency current for measurement of the impedance analyzer 48, or the change in the current phase of the high frequency current for measurement relative to the resistivity Q Data is included. These data are used for the calculation of the film thickness t or for the correction of the distance D _SF between the eddy current loss measuring sensor and the conductive film 9.

The control computer 42 reads the recipe file from the memory 52 and controls each of the aforementioned components of the measuring device 1 based on the measurement program included in the recipe file.

5 and 6 show specific examples of the measurement data table included in the recipe file. FIG. 5 shows the change in the inductance L (H) and the change in the resistance value R (Ω) of the eddy current loss measuring sensor 20 with respect to the distance D _SF between the eddy current loss measuring sensor 20 and the conductive film 9. It is an example in which t (0, 0.15, 1.0, 2.0) mu m is represented as a parameter. 6 shows the values of the inductance H and the resistance value of the eddy current loss measuring sensor 20 which change in response to the distance D _SF between the eddy current loss measuring sensor 20 and the conductive film 9. ( ₁ , ₂ ) is an example showing as a parameter. 5 and 6, the graph shown by the solid line shows the change of inductance L, and the graph shown by the dotted line shows the change of resistance value R. In FIG.

The film thickness calculating section 54 of the control computer 42 calculates the film thickness t of the conductive film 9 by matching the measurement result supplied from the impedance analyzer 48 with the data table in the recipe file.

Hereinafter, the film thickness measuring method using the film thickness measuring apparatus 1 shown in FIG. 4 is demonstrated.

The film thickness measuring apparatus 1 of this embodiment can perform the above-mentioned film thickness measurement in a pipeline form in parallel with the film formation process, the etching process, or the polishing process of a conductive film in a semiconductor manufacturing process.

As a measuring method of a film thickness, the 1st measuring method which measures, keeping the distance between the conductive film 9 and the eddy current loss measuring sensor 20 constant, and the conductive film 9 and the eddy current loss measuring sensor 20 A second measurement method of correcting the measured value of the film thickness t calculated from the measurement result of the impedance analyzer 48 by using the measurement result of the distance between the conductive film 9 and the eddy current loss measuring sensor prior to the measurement of the film thickness. The third measurement method of acquiring a change in the distance between the cells 20 as a data table in advance and measuring the film thickness of the conductive film 9 while eliminating measurement errors due to warpage and the like based on the data table is provided. have.

The first measurement method includes a process of operating both the X-Y-Z stage 36 and the Z stage 34 by the stage driver 38 based on the measurement result of the optical displacement sensor 32. The second method also includes a process of correcting the measured value of the film thickness t based on the measurement result of the optical displacement sensor 32 without operating the Z stage 34. In addition, the third measuring method includes a process of calculating approximately the displacement of the film thickness measuring point in the measuring range with respect to the distance measuring result obtained by the shake scan.

In the film thickness measuring apparatus 1 shown in FIG. 4, although it is applicable to either the 1st measuring method or the 2nd measuring method, the case where it applies to the 1st measuring method is demonstrated below.

During the measurement, a value serving as a measurement reference (hereinafter referred to as a reference value) is measured sequentially, and a measurement error is corrected (first correction processing). This is because the temperature around the film thickness measuring device 1 changes during the film forming process, the etching process, or the polishing process, or fluctuations occur in the impedance analyzer 48 itself. Because there is something to do. Specifically, the impedance of the eddy current loss measurement sensor, the current value of the high frequency current, or the like in the region where the eddy current loss is not always affected by the eddy current loss in the peripheral region of the XYZ stage 36 in parallel with the thickness measurement of the conductive film 9. The phase of the high frequency current is measured sequentially. For example, as shown in FIG. 7, with the passage of the formation time t, the inductance of the region where the conductive film 9 is not formed is L _0tO at the measurement start time t ₀ and increases from t ₁ to L _0t1 . In this case, it can be determined that (L _0t1 -L _0tO ) is a measurement error. Therefore, the correction process which subtracts by _L0tO with respect to _L1t1 as a result of the measurement of the area | region where the electroconductive film 9 was formed is performed.

First, the frequency f of the high frequency current supplied from the high frequency power source 44 is set. This is optimally based on a data table showing the relationship between the film thickness in the recipe file and the resolution with reference to the target film thickness t, that is, the design film thickness value, when forming the conductive film 9 to be measured. Set the frequency f.

FIG. 8 shows an example in which the relationship between the film thickness t (µm) of the conductive film 9 and the resolution (µm) of the measuring device is measured as the frequency f as a parameter. As can be seen from the graph of FIG. 8, the thinner the target film thickness t of the conductive film 9 is, the higher the frequency f of the high-frequency current to be used can increase the resolution of the apparatus. This utilizes a feature in which the depth of penetration of the eddy current into the conductive film is changed by the frequency of the magnetic field that excites the eddy current.

In this way, a high frequency current having a frequency f is supplied to the eddy current loss measuring sensor 20, a magnetic field of high frequency is generated from the eddy current excitation coil 24, and the magnetic flux that starts to leak from the opening 16 is transferred to the conductive film 9. When passed through, the eddy current is excited to the conductive film 9, and the eddy current loss P represented by the following formula (1) occurs.

Here, the resistivity of the conductive film 9 is given in advance from the material of the conductive film 9 to be formed.

When such eddy current loss P occurs in the conductive film 9, the impedance of the receiving coil 22, the current value of the measurement high frequency current flowing in the receiving coil 22 or the high frequency current flows in accordance with the film thickness t of the conductive film 9. Phase changes.

9 shows an example in which changes in inductance and resistance values of the eddy current loss measuring sensor are measured when the film thickness t of the conductive film 9 changes as the film formation progresses. In FIG. 9, the graph shown by the solid line shows the change of inductance L, and the graph shown by the dotted line shows the change of resistance value R. In FIG.

The impedance analyzer 48 monitors the change as shown in FIG. 9 and supplies it to the control computer 42. The film thickness calculating section 54 of the control computer 42 calculates and outputs the film thickness t while referring to a data table which shows the relationship between the film thickness t and the film resistance value previously created and written in the recipe file.

The film thickness measuring apparatus 1 processes the above-described film thickness measurement over the entire surface of the wafer 8. That is, the X-Y-Z stage 36 is continuously moved in the order previously set in the recipe file, and the surface of the wafer 8 is thus scanned by the eddy current loss measuring sensor 20. The control computer 42 outputs the value of the film thickness t calculated by the film thickness calculating section 54 in correspondence with the (X, Y) coordinates of the wafer 8.

When the pattern is formed on the surface of the wafer 8, or the film forming step, the etching step, or the CMP (Chemical Mechanical Polishing) polishing step progresses, the film of the conductive film 9 is in accordance with the movement of the stage 36. The thickness t changes. Therefore, when scanning the wafer 8 on the eddy current loss measuring sensor 20, the eddy current loss measuring sensor is caused by the warp of the wafer 8, the inclination of the XYZ stage 36, or the inclination of the Z stage 34. Although the distance D _SF of the surface of the 20 and the conductive film 9 changes, in the present embodiment, the control computer 42 makes the distance D _SF constant based on the measured value of the optical displacement sensor 32. The control signal is supplied to the stage driver 38. Based on this control signal, the stage driver 38 drives the XYZ stage 36 or the Z stage 34 or both in the z-direction, thereby between the eddy current loss measurement sensor 20 and the conductive film 9. The distance D _SF is kept constant.

In the above-mentioned embodiment, the reference value was sequentially measured during the measurement in the region where the conductive film was not formed, and the measurement error was corrected based on this. However, the reference value and its measuring method are not limited to the above embodiment. For example, a conductive film having a predetermined thickness is formed in advance in an area deviating from the influence of the eddy current, and the XYZ stage 36 is moved to the position of the conductive film prior to the film thickness measurement, so that the impedance of the eddy current loss measuring sensor 20 is reduced. The current value of the high frequency current for measurement or the phase of the high frequency current for measurement may be measured, and the measurement error may be corrected as the reference value. The reference value is not limited to one, and a plurality of measurement conductive films having a plurality of film thicknesses and a plurality of types of conductivity are formed in advance in an area deviating from the influence of eddy currents, depending on the number and type of film forming processes. The measurement error may be corrected using the reference value of.

Here, the conductive film 9 to be measured is a circuit pattern or base conductive film 19 formed on the semiconductor substrate 8 and containing a conductive material, as schematically illustrated in the cross-sectional view of FIG. 10, for example. It may be formed in a phase. In this case, when the eddy current loss is to be measured on the conductive film 9, the eddy current also occurs in the conductive material in the basic circuit pattern or the basic conductive film 19. For this reason, the impedance analyzer 48 measures not only the conductive film 9 to be measured but also the eddy current loss in the basic circuit pattern or the basic conductive film.

In the film thickness measuring apparatus 1 of this embodiment, the measurement error by such a basic circuit pattern or a basic electroconductive film is eliminated by repeating the above-mentioned series of procedures. That is, before forming the electroconductive film 9, the film thickness (henceforth an underlayer film thickness value) obtained from the electroconductive material of the circuit pattern or the base electroconductive film 19 is measured. Next, after the conductive film 9 is formed on the circuit pattern or the basic conductive film 19, the total film thickness value of the lower layer film thickness value and the film thickness value of the conductive film 9 is measured. Finally, the lower layer thickness value measured beforehand is subtracted from the total film thickness value after a measurement. Thereby, the film thickness of only the conductive film 9 can be measured correctly. In addition, when performing the film thickness measurement parallel to the film formation process of the electroconductive film 9, the result of subtracting the above-mentioned lower layer film thickness value previously obtained from the measured value of the total film thickness value is converted into the result of the electroconductive film 9 It outputs as a film thickness value.

(b) Second Embodiment of Film Thickness Measuring Apparatus

11 is a block diagram schematically showing the configuration of a second embodiment of a film thickness measurement apparatus according to the present invention. The film thickness measuring apparatus 2 shown in FIG. 11 is provided with the eddy current loss measuring sensor 10 of the excitation reception integrated type shown in FIG. 1 mentioned above. In this embodiment, the impedance analyzer 49 further serves as a high frequency power supply, and supplies a high frequency current to the excitation receiving integrated coil 12 (see FIG. 1). The other structure is substantially the same as the film thickness measuring apparatus 1 shown in FIG.

The control method of the film thickness measuring apparatus 2 of this embodiment and the film thickness measuring method using the same are substantially the same as the method described above in (a) except that the impedance analyzer 49 also serves as a high frequency power supply. same. Therefore, below, the case where the above-mentioned 2nd measuring method is applied about the measuring method using the measuring apparatus 2 of this embodiment is demonstrated typically.

At the time of measurement, similarly to the above-mentioned first measurement method, measurement reference values are measured sequentially during measurement, and the measurement error is corrected (first correction process). As described above, instead of measuring the reference values sequentially during the measurement, one or a plurality of reference values may be obtained prior to the measurement from the previously formed measurement conductive film, and the measurement error may be corrected based on the measurement values. .

At the start of measurement, first, the frequency f of the high frequency current is set based on the design film thickness value and the data table in the recipe file.

Next, the high frequency current with the frequency f set as described above is supplied from the impedance analyzer 49 to the eddy current loss measuring sensor 10, the high frequency magnetic field is excited by the coil 12, and the eddy current is locally applied to the conductive film 9. Here it is.

Under the influence of the eddy current loss due to the eddy current, the impedance of the coil 12, the current value of the high frequency current supplied to the coil 12, or the phase of the high frequency current supplied to the coil 12 changes, so that the impedance analyzer ( 49 measures changes in these values and supplies the measurement results to the control computer 42. The film thickness calculating section 54 of the control computer 42 calculates and outputs the film thickness t while referring to a data table which shows the relationship between the film thickness t previously created and written in the recipe file and the resistance value of the film.

The stage driver 38 continuously moves the X-Y-Z stage 36 in the order set in advance in the recipe file. Thus, the eddy current loss measurement sensor is scanned on the surface of the wafer 8.

In the present embodiment, the film thickness calculating unit 54 corrects the calculated film thickness value based on the measured value D _SF supplied from the optical displacement sensor 32 (second correction process). Correction of the film thickness value is processed based on the measurement data table (see FIG. 5) in the recipe file.

In addition, the control computer 42 outputs the film thickness values obtained by the calculation process and the correction process in correspondence with the (X, Y) coordinates of the wafer 8. In this way, the above-described film thickness measurement is processed over the entire surface of the wafer 8.

Thus, according to the film thickness measuring apparatus 2 of this embodiment, since the calculated film thickness value is correct | amended based on the measured value _DSF , unlike the film thickness measuring apparatus 1 mentioned above, the stage drive part 38 By controlling the relative positional relationship between the XYZ stage 36 and the Z stage 34, it is not necessary to keep the distance between the conductive film 9 and the eddy current loss measuring sensor 10 constant. As a result, the eddy current loss measuring sensor can be scanned on the wafer 8-L at a higher speed, and high-precision film thickness monitoring can be performed in real time.

(c) Third Embodiment of Film Thickness Measuring Apparatus

Next, a third embodiment of the film thickness measuring apparatus according to the present invention will be described with reference to the drawings.

The film thickness measuring apparatus 3 of this embodiment is equipped with the conventional excitation receiving integrated eddy current loss measuring sensor 120 as an eddy current loss measuring sensor. Since the other structure is substantially the same as the film thickness measuring apparatus 2 shown in FIG. 11, the overall schematic diagram is abbreviate | omitted. In addition, the control method of the film thickness measuring apparatus 3 of this embodiment, and the film thickness measuring method using the same are also substantially the same as the method mentioned above in (a) or (b). Therefore, below, the eddy current loss measuring sensor 120 is demonstrated with reference to FIG.

The eddy current loss measuring sensor 120 of the film thickness measuring apparatus 3 of this embodiment has the cylindrical excitation reception integrated coil 12 and the insulating member 126 provided so that the coil 12 may be covered. . The insulating member 126 is formed of an insulating material such as resin or ceramics. The coil 12 is connected to an impedance analyzer 49 (see FIG. 11).

The eddy current loss measuring sensor 120 receives an input of a high frequency current from the impedance analyzer 49 to excite a high frequency magnetic field, and thus receives a synthesized magnetic field changed by the eddy current excited by the conductive film 9 to be measured. The current reflecting the eddy current loss is supplied to the impedance analyzer 49. The magnetic flux line MF10 generated by the coil 12 passes through the central axis of the coil 12 and leaks from below the coil 12, and then returns to the sensor 120 side to draw an inverted parabola, and the insulating member 126 is moved. A magnetic path called back to the central axis of the coil 12 is formed via. Therefore, when the eddy current loss measurement sensor 120 is disposed above the conductive film 9 at a predetermined distance, the flux line MF10 leaked to the outside from the central axis of the coil 12 passes through the conductive film 9. Because control is possible, eddy currents are excited only around the magnetic field. From the high frequency current outputted from the coil 12 in response to the synthesized magnetic field changed by the eddy current, the impedance analyzer 49 changes the impedance of the eddy current measuring sensor 120, the current value of the high frequency current, or the phase of the high frequency current. By using), the amount of eddy current loss can be measured.

As described above, according to the present embodiment, the amount of eddy current loss can be measured even by using a conventional eddy current loss measuring sensor, so that the film thickness t of the conductive film can be measured by the above-described measurement procedure. The measuring method may be either of the first measuring method or the second measuring method described above.

(d) Fourth Embodiment of Film Thickness Measurement Apparatus

Next, a fourth embodiment of the film thickness measuring apparatus according to the present invention will be described with reference to the drawings.

Fig. 13 is a schematic diagram showing the main part of the film thickness measuring apparatus of the present embodiment. As shown in FIG. 13A, the film thickness measuring apparatus 3 of the present embodiment includes the back surface of the semiconductor wafer 8 in addition to the eddy current loss measuring sensor 20 disposed above the conductive film 9. An eddy current loss measuring sensor 20 disposed on the side, that is, the side opposite to the surface on which the conductive film 9 is formed, and a Z-stage 35 supporting the sensor from the upper surface. The film thickness measuring apparatus 3 also includes an X-Y-Z stage 37 that supports the semiconductor wafer 8 at its periphery instead of the X-Y-Z stage 36. The other structure of the film thickness measuring apparatus 3 is substantially the same as the film thickness measuring apparatus 1 shown in FIG.

With such a configuration, the film thickness measuring apparatus 3 of the present embodiment measures not only the eddy current loss measuring sensor 20 disposed above the conductive film 9 but also the eddy current loss measuring disposed on the back side of the wafer 8. The sensor 20 also excites a high frequency magnetic field, generates an eddy current in the conductive film 9 through the wafer 8, detects the synthesized magnetic field changed by the generated eddy current in the above-described procedure, and The film thickness is measured.

In this way, since the eddy current loss measurement sensor 20 is also disposed on the back side of the wafer 8, on the back side, the formation of the conductive film 9 formed on the wafer 8 in the film forming process or the etching process is prevented. Concerns are resolved. Therefore, for example, as shown in Fig. 13B, the upper surface of the eddy current loss measuring sensor 20 can be measured by contacting the back surface of the wafer 8 with measurement. In addition, in the CMP polishing step, scanning is avoided while avoiding contact with the polishing tool. As a result, the measurement constraints are greatly reduced. Thus, according to this embodiment, the film thickness measuring apparatus excellent in both the degree of freedom of design and the throughput of the measurement is provided. In addition, the specific measuring method is substantially the same as the procedure described in 1st Embodiment or 2nd Embodiment.

(e) Fifth Embodiment of Film Thickness Measuring Apparatus

Next, a fifth embodiment of the film thickness measuring apparatus according to the present invention will be described with reference to the drawings. A feature of the film thickness measuring apparatus 4 according to the present embodiment includes a plurality of eddy current loss measuring sensors 10, whereby the film thickness distribution of the conductive film 9 is collectively simplified while greatly simplifying the scanning order of the sensors. The point is to measure at high speed. The other structure of the film thickness measuring apparatus 4 is substantially the same as the film thickness measuring apparatus 2 shown in FIG.

It is a schematic diagram which shows the principal part of 5th Embodiment of the film thickness measuring apparatus which concerns on this invention. 14A to 14C are plan views seen from the upper side of the wafer 8, respectively, and show a typical arrangement of a plurality of sensors.

14A illustrates an example in which the eddy current loss measurement sensor 10 is arranged to form one row at a predetermined interval. In the case of this example, as shown by arrow A1 of Fig. 14A, the entire surface of the conductive film 9 formed on the surface is moved only by moving the wafer 8 in the direction orthogonal to the rows of the sensors. It can scan, and the thickness distribution of the electroconductive film 9 can be measured at high speed.

FIG. 14B is an example in which the eddy current loss measuring sensors 10 are arranged at predetermined intervals in two directions perpendicular to each other to form a cross shape. In this example, after moving the XYZ stage 36 so that the eddy current loss measurement sensor 10 located at the center of the cross shape is located above the center of the wafer 8, the arrow A2 in Fig. 14B is shown. As shown in Fig. 1, only by rotating in a clockwise or counterclockwise direction, the entire surface of the conductive film 9 formed on the surface thereof can be scanned, so that the film thickness distribution of the conductive film 9 can be measured at high speed. Can be.

FIG. 14C shows an example in which the eddy current loss measurement sensor 10 is disposed radially. By disposing in this way, the eddy current loss measuring sensor 10 corresponds to all of the regions necessary for the measurement of the film thickness of the conductive film 9, and the film thickness of the conductive film 9 is measured almost over the entire surface in one measurement. can do. Therefore, in the case of this example, it is not necessary to move the stage 36 during a film formation process. Thereby, since the film thickness of the electroconductive film 9 can be measured collectively, a film thickness distribution can be measured very quickly. As a result, the film thickness measuring apparatus which can measure collectively with high precision is provided, even if the measurement time is limited when forming very thin electrically conductive formation. In addition, in combination with the present embodiment and the above-described fourth embodiment, when disposed on both the upper side and the rear side of the conductive film 9, a larger number of eddy current loss measurement sensors 10 can be arranged at one time, thereby measuring the measurement speed and The precision can be further improved.

(f) 6th Embodiment of Film Thickness Measurement Apparatus

Next, a sixth embodiment of the film thickness measuring apparatus according to the present invention will be described with reference to FIGS. 15 to 17. The characteristic of this embodiment is to arrange | position a laser displacement sensor coaxially with the central axis of the excitation receiving integrated coil which comprises an eddy current loss measuring sensor, and measures the eddy current loss and the measurement of the distance of the eddy current loss measuring sensor and the surface of a conductive film. At the same time it is realized.

Fig. 15 is a block diagram schematically showing the configuration of the film thickness measuring apparatus of the present embodiment. As apparent from the film thickness measuring apparatus 2 shown in FIG. 11, the film thickness measuring apparatus 5 shown in FIG. 15 includes a laser displacement sensor 63 as an optical displacement sensor, and an optical displacement sensor. The laser displacement sensor controller 58 is provided as a controller. In addition, the film thickness measuring apparatus 2 is provided with an air core type excitation receiving integrated coil 68 as an eddy current loss measuring sensor. The excitation receiving integrated coil 68 and the laser displacement sensor 63 constitute an eddy current loss measuring sensor unit 60. The other structure of the film thickness measuring apparatus 2 is substantially the same as the film thickness measuring apparatus 2 shown in FIG. In this embodiment, the control computer 42, the laser displacement sensor controller 58, and the stage drive part 38 constitute a distance measurement error correction means.

FIG. 16 is a cross-sectional view schematically showing a specific configuration of the eddy current loss measuring sensor unit 60 included in the film thickness measuring apparatus 5 shown in FIG. 15. The laser displacement sensor 63 is disposed above the excitation receiving integral coil 68 such that the intermediate points of the laser oscillation portion and the laser light receiving portion substantially coincide with the central axis of the excitation receiving integral coil 68. Therefore, the laser light LB1 generated from the laser oscillation part is irradiated to the surface of the conductive film 9 via the air core of the coil 68, and the reflected light LB2 also enters the laser light receiving part via the air core of the coil 68 in the same way. do. As a result, a signal indicating the distance D1 between the laser displacement sensor 63 and the conductive film is supplied to the control computer 42 through the laser displacement sensor controller 58. In the memory 52, the distance D2 between the lower side of the laser displacement sensor 63 and the lower side of the coil 68 is stored in advance, and the control computer 42 divides the distance D2 from the distance D1 to obtain an eddy current. The distance D _SF between the loss measuring sensor unit 60 and the conductive film 9 is calculated. In the above-described embodiment, since the optical displacement sensor and the eddy current loss measuring sensor were adjacent to the conductive film 9 in the horizontal direction, the measurement result by the optical displacement sensor and the eddy current loss measuring sensor and the conductive film 9 were not included. An error may occur between the actual distances. On the other hand, since the eddy current loss measuring sensor unit 60 shown in FIG. 15 irradiates the laser beam LB1 to a position substantially coincident with the intersection of the central axis of the coil 68 and the conductive film 9, the eddy current loss measuring sensor The distance D _SF between the unit 60 and the conductive film 9 can be measured accurately.

Next, the film thickness measuring method using the film thickness measuring apparatus 5 shown in FIG. 15 is demonstrated. The film thickness measuring apparatus 5 of this embodiment can be applied almost similarly to any of the above-described first to third measuring methods. However, as described above, according to the eddy current loss measuring sensor unit 60, the position where the laser beam LB1 is irradiated to the conductive film 9 is substantially the same as the position of the intersection where the centerline of the coil falls on the surface of the conductive film 9. In the case of applying the first or second method to the film thickness measuring apparatus 5 of the present embodiment, the characteristic of the distance D _SF between the eddy current loss measuring sensor unit 60 and the conductive film 9 is determined. This is because the measurement and the measurement of the eddy current loss can be performed simultaneously. In the above-described embodiment, since the optical displacement sensor is disposed in isolation from the eddy current loss measurement sensor, the eddy current loss measurement sensor must be moved by the distance in order to avoid measurement errors. However, measurement errors may occur due to vibration of the stage during the movement or vibration of the eddy current loss measurement sensor itself. On the other hand, according to the present embodiment, since the distance D _SF between the eddy current loss measuring sensor unit 60 and the conductive film 9 can be measured directly, not only this measurement error can be avoided, but also the number of operations of the stage Since it can be reduced, the burden on the performance of a stage can be reduced. As a result, the film thickness can be measured more accurately and at high speed, and the structure of the film thickness measuring device can be further miniaturized and simplified.

Here, the film thickness measurement by a 3rd measuring method using the film thickness measuring apparatus 5 of this embodiment is demonstrated, referring FIG.

First, prior to the film thickness measurement, the distance D _SF between the sensor unit conductive films 9 is measured by the laser displacement sensor 63 by a predetermined score in the desired film thickness measurement range in the conductive film 9. Release. In this measurement result, a measurement error due to the warpage of the wafer appears. 17 is a graph showing an example of the relationship between the distance D _SF between the position on the wafer and the sensor unit conductive film 9. As shown in the graph lm in FIG. 17, the distance D _SF is greatly changed as a result of the measurement.

Next, the control computer 42 performs a process such as smoothing or polynomial approximation to remove the measurement error, and stores the result in the memory 52. The graph 1c shown in FIG. 17 shows an example of error processing performed on the measurement result shown in the graph lm.

Next, the frequency f of the high frequency current supplied by the impedance analyzer 49 is set. That is, with reference to the target film thickness t when the conductive film 9 is formed, the frequency f that is considered to be optimal is set based on the data table (see FIG. 8) showing the relationship between the film thickness in the recipe file and the resolution. Then, a high frequency current having this frequency f is supplied to the excitation receiving integrated coil 68 to generate a magnetic field. By this magnetic field, the eddy current is excited to the conductive film 9, and the eddy current loss P represented by the above formula (1) is generated in the conductive film 9.

When the eddy current loss P occurs in the conductive film 9, the impedance of the eddy current loss measuring sensor unit 60 and the current of measurement high frequency current flowing through the excitation receiving integrated coil 68 according to the film thickness t of the conductive film 9 The value or phase of the high frequency current changes (see FIG. 9).

This change is monitored by the impedance analyzer 49 and supplied to the control computer 42. The film thickness calculating section 54 of the control computer 42 is provided between the data table indicating the relationship between the film thickness t and the resistance value of the film, which has been previously created and written in the recipe file, and the sensor unit conductive film 9 after the measurement error elimination process. The film thickness t is calculated and output while referring to the data table of the change in the distance D _SF .

The film thickness measuring apparatus 5 performs the above-described film thickness measurement by a predetermined score in the desired measurement range of the wafer 8. Here, since an approximation function has already been obtained by preliminary scanning to reduce the error, the measurement point in the eddy current measurement does not need to coincide with the measurement point of the preliminary scan. The film thickness calculating section 54 calculates the film thickness t of the conductive film 9 while referring to the approximation function obtained in advance.

According to the above-described third film thickness measuring method, the data table of the change of the distance D _SF between the sensor unit conductive films 9 is obtained in advance using the laser displacement sensor 63, and the measurement error is determined in this data table. Since the film thickness is calculated using the removed approximation function, the problem that the precision of the optical displacement sensor is relatively low can be solved while stopping the measurement score of the eddy current loss to the minimum necessary. As a result, the deterioration of the displacement measurement accuracy for the conductive film having a large reflectance on the LSI pattern or the conductive film having a rough surface can be suppressed, so that the above-described third film thickness measuring method does not require displacement measurement for each wafer. This is particularly effective when the warpage of the wafer is not significantly different from each other, for example, a wafer in the same lot, a wafer on which the same circuit pattern is formed, or a wafer having passed through the same process. In addition, in this embodiment, although the case where the XYZ stage 36 is provided was demonstrated, even when the XYZ stage 36 cannot be used like the conveyance of the wafer 8, for example, a robot arm may be used. The film thickness of the conductive film 9 can be measured by moving the wafer under the eddy current loss measuring sensor unit 60.

(g) Seventh Embodiment of Film Thickness Measurement Apparatus

Next, a seventh embodiment of the film thickness measuring apparatus according to the present invention will be described with reference to FIG. This embodiment is a form in which the eddy current loss measurement sensor unit 60 is disposed on the back side of the conductive film 9 in the film thickness measuring apparatus 5 shown in FIG. 15.

18 is a schematic view showing the main part of the film thickness measuring apparatus of the present embodiment. As shown in Fig. 18A, the film thickness measuring apparatus 5 'of the present embodiment is disposed on the back side of the semiconductor wafer 8, that is, on the side opposite to the surface on which the conductive film 9 is formed. An eddy current loss measuring sensor unit 60 and a Z-stage 35 supporting the sensor from an upper surface thereof. Moreover, the film thickness measuring apparatus 5 'is equipped with the X-Y-Z stage 37 which supports the semiconductor wafer 8 at the peripheral part instead of the X-Y-Z stage 36 like 4th Embodiment shown in FIG. The other structure of the film thickness measuring apparatus 5 'is substantially the same as the film thickness measuring apparatus 5 shown in FIG.

With this configuration, the film thickness measuring apparatus 5 ′ of the present embodiment excites a high frequency magnetic field by the excitation receiving integrated coil 68 disposed on the back side of the wafer 8, and conducts a conductive film through the wafer 8. An eddy current is generated in (9), a synthetic magnetic field changed by the generated eddy current is detected, and the film thickness of the conductive film 9 is measured. Further, the distance D _SF between the sensor unit conductive film is obtained by obtaining the distance D3 between the back surface of the wafer 8 and the eddy current loss measurement sensor unit 60 and the thickness Ts of the wafer 8 in advance. Ts) can be calculated.

For example, as shown in FIG. 18B, the upper surface of the eddy current loss measuring sensor unit 60 can be measured by contacting the back surface of the wafer 8. In this case, it is not necessary to measure the displacement.

Thus, according to the film thickness measuring apparatus 5 'of this embodiment, since the eddy current loss measuring sensor unit 60 is arrange | positioned at the back side of the wafer 8, in the film formation process or an etching process, the wafer 8 The problem of hindering the formation of the conductive film 9 and the like formed on the X-rays is solved. In addition, in the CMP polishing step, the measurement does not need to be avoided while avoiding contact with the polishing tool. As a result, the measurement constraint is greatly reduced, and therefore, it can be operated as an In-situ type film thickness measuring apparatus that measures the film thickness in real time in a manufacturing process such as a film forming step, polishing step, or etching step. Thus, according to this embodiment, the film thickness measuring apparatus which is excellent also in all about the freedom of design, the precision of a measurement, and the throughput is provided. The specific measuring method of the film thickness measuring apparatus 5 'is substantially the same as the 1st-3rd measuring method mentioned above.

In the present embodiment, the embodiment in which the eddy current loss measuring sensor unit is disposed only on the back side of the wafer has been described. Similarly to the fourth embodiment shown in FIG. 13, the eddy current is also present on the upper side besides the back side of the conductive film 9. The loss measuring sensor unit 60 may be disposed to measure the film thickness on both sides.

(h) 8th Embodiment of Film Thickness Measurement Apparatus

Next, an eighth embodiment of the film thickness measuring apparatus according to the present invention will be described with reference to FIGS. 19 and 20. A feature of the present embodiment lies in that the distance between the sensor unit conductive films is measured by providing a capacitive displacement sensor in place of the above-described optical displacement sensor or laser displacement sensor.

19 is a block diagram schematically showing the configuration of the film thickness measuring apparatus of the present embodiment. The film thickness measuring apparatus 6 shown in FIG. 19 uses the XYZ stage 36, the stage driver 38, the impedance analyzer 49, and the control computer 42 similarly to the second to seventh embodiments described above. In addition to this, the eddy current loss measuring sensor unit 70 and the capacitive displacement sensor controller 88 which are characteristic in this embodiment are further provided.

The eddy current loss measuring sensor unit 70 is an eddy current loss measuring sensor, and an excitation receiving integral coil 12, an insulating member 126 formed to cover the excitation receiving integral coil 12, and a capacitive displacement sensor electrode 72. It includes. The coil 12 receives a high frequency current from the impedance analyzer 49 to form a high frequency magnetic field, generates an eddy current locally in the conductive film 9, and simultaneously generates a magnetic field and coil 12 generated by the eddy current. Receive a composite magnetic field with the magnetic field generated by

The capacitive displacement sensor controller 88 is connected to the capacitive displacement sensor electrode 72 in the eddy current loss measuring sensor unit 70 and is connected to the ground by the wiring G1. In addition, the wafer 8 is connected to the ground by the wiring G3 on the side surface thereof. As a result, the conductive film 9 is also maintained at the ground potential. As a result, the capacitive displacement sensor electrode 72 and the conductive film 9 constitute electrodes on both sides of the capacitor, and the capacitive displacement sensor controller 88 is the capacitive displacement sensor electrode 72 and the conductive film ( The capacitance between 9) is measured and the measurement result is supplied to the control computer 42. The control computer 42 calculates the distance between the capacitive displacement sensor electrode 72 and the conductive film 9 from the measurement result of the capacitive displacement sensor controller 88. In addition, as shown in FIG. 19, instead of connecting the side surface of the wafer 8 to the ground, a portion of the surface area of the conductive film 9 that does not affect the film thickness measurement, for example, an end portion is connected to the wiring G4. May be connected to the ground via the wiring G2 passing through the XYZ stage 36, or may be connected to the ground at the rear side of the end portion thereof. In FIG. 19, although G2 to G4 are shown as wirings for holding the conductive film 9 at the ground potential, these are alternative and can be appropriately selected according to the measurement environment. For example, if the form in which the conductive film 9 is directly connected to the ground is selected, measurement can be performed even when the X-Y-Z stage 36 cannot be used, such as during the conveyance of the wafer 8.

The specific configuration of the capacitive displacement sensor electrode 72 will be described with reference to FIG. 20.

FIG. 20A is a schematic cross-sectional view of the eddy current loss measurement sensor unit 70 shown in FIG. 19, and FIG. 20B is a bottom view of the eddy current loss measurement sensor unit 70. The capacitive displacement sensor electrode 72 is a ring-shaped thin film electrode of thickness Te formed of a high resistance material, and is disposed at the bottom of the insulating member 126 so as to wind up the excitation receiving integrated coil 12. In this embodiment, the ring-shaped central axis of the capacitive displacement sensor electrode 72 coincides with the central axis of the coil 12. The thickness Te of the sensor electrode 72 is about 10-50 micrometers in this embodiment. Further, a recess having a depth corresponding to the thickness Te of the sensor electrode 72 is provided around the bottom of the insulating member, and the sensor electrode 72 is recessed so that its surface is located in the same plane as the bottom of the coil 12. Is inserted into the part. Thus, the distance measured by the capacitive displacement sensor coincides with the distance D _SF between the coil 12 and the conductive film 9.

The size of the outer diameter ED of the capacitive displacement sensor electrode 72 is selected to be substantially equal to the diameter of the region where the eddy current is excited by the coil 12. As a result, since the capacitance value detected from the sensor electrode 72 is averaged over the region where the eddy current loss is measured, the measurement accuracy of the distance D _SF between the coil 12 and the conductive film 9 is improved. As a result, the precision of the film thickness measurement also improves. In this embodiment, the outer diameter ED is about 6-16 mm. In addition, the magnitude of the inner diameter ID of the capacitive displacement sensor electrode 72 is such that the high frequency magnetic field excited by the coil 12 does not affect the measurement accuracy of the capacitance and the coil 12 of the inner circumference of the electrode 72. It is sufficiently isolated from the outer circumferential surface of and is selected to have a sufficient surface area of the electrode in the capacitance measurement. In this embodiment, the distance between the outer peripheral surface of the coil 12 and the inner peripheral surface of the electrode 72 is about 1-2 mm. In the eddy current loss measurement sensor unit 70 of the present embodiment, an insulating material is also filled in the core of the coil 12 to form a part of the insulating member 126, but the eddy current loss measurement shown in FIG. Like the sensor unit 60, a concentric structure may be used.

Although the film thickness measuring method using the film thickness measuring apparatus 6 of this embodiment is substantially the same as the 1st and 2nd measuring method demonstrated in 1st-6th embodiment, the characteristic of this embodiment is the measurement of an eddy current loss. And the distance D _SF between the coil 12 and the conductive film 9 can be simultaneously measured. Therefore, the measurement error of the distance D _SF between the coil 12 and the conductive film 9 due to the vibration of the XYZ stage 36 or the vibration of the eddy current loss measuring sensor unit 70 can be greatly reduced. As a result, since the film thickness can be measured with high accuracy and at high speed, the throughput of the measurement is further improved. In addition, since the number of stage movements is reduced, the burden on stage performance can be reduced, and the structure of the film thickness measuring apparatus can be further miniaturized and simplified. In addition, since the distance D _SF between the coil 12 and the conductive film 9 is measured using electrostatic capacity, the surface reflectance and surface roughness of the conductive film 9 are not affected. Thereby, also with respect to the conductive film formed on the LSI pattern, the distance with the coil 12 can be measured with high precision.

(i) Ninth Embodiment of Film Thickness Measurement Apparatus

Next, a ninth embodiment of the film thickness measuring apparatus according to the present invention will be described with reference to FIG. The characteristic of the film thickness measuring apparatus 6 'of this embodiment is in the shape of the capacitive displacement sensor electrode 74 with which the eddy current loss measuring sensor unit 70' is equipped. Since the other structure of the film thickness measuring apparatus 6 'is the same as that of the film thickness measuring apparatus 6 shown in FIG. 20, only a different point is demonstrated below.

FIG. 21A is a schematic cross-sectional view of the eddy current loss measuring sensor unit 70 'included in the film thickness measuring apparatus 6' of the present embodiment, and FIG. 21B is an eddy current loss measuring sensor unit 70. As shown in FIG. Bottom view of '). As shown in Fig. 21B, the capacitive displacement sensor electrode 74 disposed in the eddy current loss measuring sensor unit 70 'is composed of four arc-shaped electrode pieces 74a to 74d, These electrode pieces are arranged to form a ring for winding the coil 12.

According to this embodiment, since a sensor electrode is comprised by the some electrode piece, it can prevent that an eddy current generate | occur | produces in a sensor electrode by the magnetic field excited by the coil 12. As shown in FIG. Thereby, the precision of a film thickness measurement can be improved further.

Since the film thickness measuring method using the film thickness measuring apparatus 6 'of this embodiment is the same as that of 8th embodiment mentioned above, the description is abbreviate | omitted.

(j) Tenth embodiment of the film thickness measuring device

Next, a tenth embodiment of the film thickness measuring apparatus according to the present invention will be described with reference to FIG.

In this film thickness measuring apparatus 6 shown in FIG. 19, the eddy current loss measuring sensor unit 70 is arranged on the rear surface side of the conductive film 9.

Fig. 22 is a schematic view showing the main part of the film thickness measuring apparatus of the present embodiment. As shown in Fig. 22A, the film thickness measuring apparatus 6 of the present embodiment is the back side of the semiconductor wafer 8; An eddy current loss measuring sensor unit 70 disposed on the side, that is, on the side opposite to the surface on which the conductive film 9 is formed, and a Z-stage 35 supporting the sensor on the upper surface. Moreover, the film thickness measuring apparatus 6 is equipped with the X-Y-Z stage 37 which supports the semiconductor wafer 8 at the periphery part instead of the X-Y-Z stage 36 similarly to 4th Embodiment shown in FIG. The other structure of the film thickness measuring apparatus 6 is substantially the same as the film thickness measuring apparatus 5 shown in FIG. In addition, the specific measuring method of the film thickness measuring apparatus 6 is substantially the same as the measuring method mentioned above in 9th Embodiment.

With such a configuration, the film thickness measuring apparatus 6 of the present embodiment excites a high frequency magnetic field by the excitation receiving integrated coil 12 disposed on the rear side of the wafer 8, and conducts a conductive film (through the wafer 8). An eddy current is generated in 9), a synthetic magnetic field changed by the generated eddy current is detected, and the film thickness of the conductive film 9 is measured. The distance D _SF between the sensor unit conductive films is obtained by obtaining the distance D3 of the back surface of the wafer 8 and the distance D3 of the eddy current loss measurement sensor unit 60 and the thickness Ts of the wafer 8 in advance, and then the distance D3 +. It can calculate easily by Ts).

For example, as shown in FIG. 22B, the upper surface of the eddy current loss measuring sensor unit 70 can be measured by contacting the back surface of the wafer 8.

Thus, according to the film thickness measuring apparatus 6 of this embodiment, since the eddy current loss measuring sensor unit 70 is arrange | positioned at the back side of the wafer 8, the wafer 8 in a film formation process or an etching process is carried out. The problem of preventing formation of the conductive film 9 formed on the surface and the like is solved. In addition, in the CMP polishing step, the measurement does not need to be avoided while avoiding contact with the polishing tool. As a result, the measurement constraints are greatly reduced, so that the film thickness measuring apparatus 6 of the present embodiment can be operated as an In-situ type film thickness measuring apparatus. Thus, according to this embodiment, the film thickness measuring apparatus which is excellent also in all about the freedom of design, the precision of a measurement, and the throughput is provided.

In this embodiment, the embodiment in which the eddy current loss measurement sensor unit 70 is disposed only on the back side of the wafer is described. However, as in the fourth embodiment shown in FIG. The eddy current loss measuring sensor unit 70 may also be disposed on the upper side, and the film thickness may be measured on both sides.

(3) recording media

The above-described series of measurement procedures include the first to third measurement methods, and may be stored on a recording medium such as a floppy disk or CD-ROM as a program to be executed on a computer, and may be read and executed by a computer. Thereby, the above-mentioned film thickness measuring method can be realized using the film thickness measuring apparatus provided with a displacement sensor and a general-purpose control computer. The recording medium is not limited to being portable such as a magnetic disk or an optical disk, and may be a fixed recording medium such as a hard disk device or a memory. Further, a program incorporating a series of procedures of the above-described film thickness measurement method may be distributed through a communication line (including wireless communication) such as the Internet. In addition, the program that assembles the sequence of the above-described film thickness measurement methods may be stored and distributed on a recording medium or through a wired or wireless line such as the Internet while encrypting, modulating, or compressing the program. Do.

As mentioned above, although embodiment of this invention was described, this invention is not limited to the said form, A various deformation | transformation can be added in the range which does not deviate from the summary. For example, in the embodiment of the film thickness measuring apparatus described above, the embodiment using the eddy current loss measuring sensor 20 in the fourth embodiment has been described, but the current loss measuring sensor 10 shown in FIG. It is also possible to use the current loss measurement sensor 120 shown in FIG. Similarly, although the form using the current loss measuring sensor 10 was demonstrated in 5th Embodiment, also using the current loss measuring sensor 20 shown in FIG. 2, and also measuring the current loss shown in FIG. The sensor 120 may be used. The three types of current loss measurement sensors may be appropriately combined in the same apparatus. In addition, in 6th-10th embodiment, although the eddy current loss measuring sensor unit which has an excitation receiving integrated coil was demonstrated, it is a matter of course that it is applicable also to the eddy current loss measuring sensor unit which has an eddy current excitation coil and a receiving coil. In addition, although the case where a single eddy current loss measuring sensor unit is provided was demonstrated in 6th-10th embodiment, as shown in FIG. 14, you may arrange | position a some sensor unit.

As described above, the present invention has the following effects.

That is, according to the eddy current loss measuring sensor according to the present invention, the second permeability having an opening formed on the opposite surface to the conductive film so that at least a portion of the high frequency magnetic field excitation coil is exposed on the opposite surface to the conductive film to be measured. Since the member is provided, the magnetic path can be controlled so that the magnetic flux leaks to the outside only from this opening. Thereby, a magnetic field can be concentrated in the micro area | region of the said electroconductive film, and an eddy current can be locally excited in the said electroconductive film. As a result, the eddy current loss can be measured by measuring the change in the impedance of the eddy current loss measuring sensor, the change in the current value of the high frequency current, or the change in phase of the high frequency current from the output current obtained from the receiving coil. The film thickness can be measured with high precision.

In addition, according to the film thickness measuring apparatus according to the present invention, the distance measuring means for measuring the distance between the eddy current loss measuring sensor and the conductive film, and based on the measurement result of the distance measuring means and the measurement result of the eddy current loss measuring means. Since the film thickness calculating means for calculating the film thickness of the film is provided, the measurement error depending on the distance can be reduced. Thereby, the film thickness of a conductive film can be measured with high precision.

In the film thickness measuring apparatus according to the present invention, in the case where the eddy current loss measuring sensor according to the present invention is provided, the film thickness of the conductive film can be locally managed in addition to the above-described effects. Even if the object to be measured has a relatively large variation in film thickness, such as a conductive film formed on a wafer on which a pattern is formed on the surface, the film thickness can be measured with high accuracy, and the film thickness is managed in various devices such as a CMP or a plating apparatus. You can do it.

Furthermore, in the film thickness measuring apparatus which concerns on this invention, when the said distance measuring means contains the laser displacement sensor provided in the excitation receiving integrated air core coil or the air core receiving coil above, the said eddy current loss measuring sensor and the said electroconductivity Since the measurement of the distance with the film and the measurement of the eddy current loss can be performed at the same time, it is possible to measure the film thickness of a high throughput with better accuracy.

Further, in the film thickness measuring apparatus according to the present invention, when the distance measuring means includes a capacitive displacement sensor having an electrode provided in proximity to the eddy current loss measuring sensor, the distance measurement and the eddy current loss measurement Not only can these be simultaneously performed, but the distance can be measured more accurately without being affected by the reflectance of the light on the surface of the conductive film or the roughness of the surface.

Moreover, according to the film thickness measuring method which concerns on this invention, the distance measurement process which measures the distance between the said eddy current loss measuring sensor and the said conductive film, the said distance obtained by this distance measuring process, and the eddy current loss measuring process are carried out. A film thickness calculating step of calculating the film thickness of the conductive film on the basis of the obtained change of impedance, change of current value of high frequency current or change of phase of the high frequency current is provided, so that highly accurate film thickness can be measured in a non-contact and non-destructive form. Can be realized.

In the film thickness measuring method according to the present invention, in the case where the distance measuring means includes the displacement sensor or the capacitive displacement sensor, and the distance measuring process and the eddy current loss measuring process are performed in parallel, The film thickness can be measured with higher precision and with better throughput.

Further, according to the recording medium of the present invention, the conductive film can be measured with high accuracy and high speed by using the film thickness measuring device provided with the distance measuring means and the general purpose computer.

Claims (54)

An excitation receiving integrated coil for receiving a high frequency current to excite a high frequency magnetic field to excite an eddy current to a conductive film to be measured, and to receive a composite magnetic field generated by the eddy current and the high frequency magnetic field; A first permeable member formed of a first permeable material and inserted into the excitation receiving integral coil to form a core; It is formed of a second permeable material, is provided to surround the first permeable member and the excitation receiving integral coil, and is opened so that at least a portion of the region of the excitation receiving integral coil is exposed on the opposite surface to the conductive film. Formed second permeable member Eddy current loss measuring sensor having a. An eddy current excitation coil which receives a high frequency current and excites a high frequency magnetic field to excite the eddy current to the conductive film to be measured; A receiving coil which is installed to be wound by the eddy current excitation coil in the eddy current excitation coil and receives a composite magnetic field of the magnetic field generated by the eddy current and the high frequency magnetic field; A first permeable member formed of a first permeable material and inserted into the receiving coil to form a core; It is formed of a second permeable material, is provided to surround the first permeable member, the receiving coil and the eddy current excitation coil, so that at least a portion of the region of the receiving coil is exposed on the opposite surface to the conductive film. Second permeable member having an opening Eddy current loss measuring sensor having a. The method according to claim 1 or 2, The opening has an eddy current loss measurement sensor, wherein a distance from the first permeable member is adjusted so that magnetic flux is emitted only to a local region of the conductive film. The method according to claim 1 or 2, An eddy current loss measurement sensor, wherein the surface portion of the opening, or the surface portion of the opening and the region near the opening, is formed using a third permeable material having a higher permeability than the second permeable material. The method of claim 4, wherein And the first to third permeable materials comprise an electrically insulating material. The method of claim 5, And said electrically insulating material comprises ferrite. An eddy current loss measuring sensor for receiving a high frequency current to excite a high frequency magnetic field to excite an eddy current to a conductive film to be measured, and to output the high frequency current affected by the eddy current loss due to the eddy current; The high frequency current output from the eddy current loss measuring sensor is detected, and the magnitude of the eddy current loss is measured by measuring a change in impedance of the eddy current loss measuring sensor, a change in current value of the high frequency current, or a change in phase of the high frequency current. Eddy current loss measuring means output as data to be shown, Distance measuring means for measuring a distance between the conductive film and the eddy current loss measuring sensor; Film thickness calculating means for calculating the film thickness of the conductive film based on the measurement result of the eddy current loss measuring means and the measurement result of the distance measuring means Film thickness measuring apparatus provided with. The method of claim 7, wherein The distance between the eddy current loss measuring sensor and the conductive film, the frequency of the high frequency current, the film thickness of the conductive film and the resistivity of the conductive film, and the change of the impedance of the eddy current loss measuring sensor, or the distance, The correlation between the frequency, the film thickness and the resistivity and the change in the current value of the high frequency current, or the distance, the frequency, the film thickness and the resistivity, and the change in the phase of the high frequency current And storage means for storing data for measurement indicative of The film thickness calculating means compares the measured thickness of the conductive film with a change in impedance of the measured eddy current loss measurement sensor, a change in current value of the high frequency current, or a change in phase of the high frequency current with the measurement data. Calculated A film thickness measuring apparatus, characterized in that. The method according to claim 7 or 8, A stage for supporting the substrate on which the conductive film is formed; Control means for controlling the relative positional relationship between the stage and the eddy current loss measuring sensor based on the measurement result of the distance measuring means The film thickness measuring apparatus further comprises. The method of claim 9, The control means moves the eddy current loss measuring sensor to an area deviating from the influence of the eddy current, prior to excitation of the eddy current to the conductive film, The eddy current loss measuring means measures an impedance of the eddy current loss measuring sensor measured in a region deviating from the eddy current, the current value of the high frequency current or the phase of the high frequency current as a measurement reference value, The film thickness calculating means corrects the calculated film thickness value based on the measurement reference value. A film thickness measuring apparatus, characterized in that. The method of claim 10, In the region deviating from the influence of the eddy current, a reference conductive film serving as a measurement standard is prepared in advance with a predetermined film thickness, The control means moves the eddy current loss measurement sensor to a region where the reference conductive film is prepared, prior to excitation of the eddy current to the conductive film as the measurement target, The eddy current loss measuring means measures an impedance of the eddy current loss measuring sensor measured in a region where the reference conductive film is formed, a current value of the high frequency current, or a phase of the high frequency current as a measurement reference value. A film thickness measuring apparatus, characterized in that. The method of claim 11, The reference conductive film is a plurality of reference conductive films formed with different film thicknesses from conductive materials having different conductivity, The eddy current loss measuring means measures a plurality of measurement reference values, The film thickness calculating means corrects the calculated film thickness based on the plurality of measurement reference values. A film thickness measuring apparatus, characterized in that. The method of claim 9, Stage moving means for moving the stage; Further comprising a sensor moving means for moving the eddy current loss measuring sensor, The control means includes: the stage moving means and the sensor moving means such that the eddy current loss measuring sensor scans the conductive film while maintaining a substantially constant mutual distance in parallel with the film forming step, the etching step, or the polishing step of the conductive film. To control A film thickness measuring apparatus, characterized in that. The method of claim 9, Further comprising stage moving means for moving the stage, The control means controls the stage moving means such that the eddy current loss measuring sensor scans the conductive film in parallel with the film forming process, the etching process or the polishing process of the conductive film, The film thickness calculating means receives a measurement result of the distance measuring means and corrects the calculated film thickness value. A film thickness measuring apparatus, characterized in that. The method of claim 9, And the stage is formed of an insulating material or a material having electrical conductivity such that only an eddy current of negligible measurement is generated upon receiving the high frequency magnetic field. The method according to claim 7 or 8, And a frequency control means for controlling the frequency of said high frequency current so that said high frequency current becomes a frequency in accordance with the film thickness of said conductive film. The method according to claim 7 or 8, The conductive film is formed above a circuit pattern or basic conductive film containing a conductive material, The said film thickness calculation means calculates the film thickness value of the said circuit pattern or the said basic conductive film beforehand as an underlayer film thickness value, and subtracts the said lower layer film thickness value from the film thickness value computed about the formed conductive film. A film thickness measuring apparatus, characterized in that. The method according to claim 7 or 8, The eddy current loss measurement sensor, Influence of the eddy current loss caused by the eddy current by receiving the high frequency current to excite the high frequency magnetic field to excite the eddy current to the conductive film to be measured, and to receive the composite magnetic field generated by the eddy current and the high frequency magnetic field. An excitation receiving integrated coil which outputs the received high frequency current, A first permeable member formed of a first permeable material and inserted into the excitation receiving integral coil to form a core; A second permeable member formed of a second permeable material and installed to surround the first permeable member and the excitation receiving integral coil A film thickness measuring apparatus having a. The method according to claim 7 or 8, The eddy current loss measurement sensor, An eddy current excitation coil that receives the high frequency current and excites a high frequency magnetic field to excite the eddy current to the conductive film to be measured; The high frequency current is provided to be wound by the eddy current excitation coil in the eddy current excitation coil, and receives the composite magnetic field generated by the eddy current and the high frequency magnetic field to receive the high frequency current affected by the eddy current loss caused by the eddy current. A receiving coil to output, A first permeable member formed of a first permeable material and inserted into the receiving coil to form a core; A second permeable member formed of a second permeable material and provided to surround the first permeable member, the receiving coil, and the eddy current excitation coil. A film thickness measuring apparatus having a. The method of claim 18, The second permeable member, And an opening is formed on the surface opposite to the conductive film so as to expose the excitation receiving integrated coil or at least a portion of the receiving coil. The method of claim 20, And the opening is formed by adjusting a distance to the first permeable member so that magnetic flux is emitted only to a local region of the conductive film. The method of claim 18, The surface part of the said opening part, the surface part of the said opening part, and the surface part of the area | region near the opening are formed using the 3rd permeable material with higher permeability than the said 2nd permeable material, The film thickness measuring apparatus characterized by the above-mentioned. The method of claim 22, The said 1st thru | or 3rd permeable material contains an electrically insulating material, The film thickness measuring apparatus characterized by the above-mentioned. 24. The apparatus of claim 23, wherein the electrically insulating material comprises ferrite. The method according to claim 7 or 8, The eddy current loss measurement sensor receives the high frequency current to excite the high frequency magnetic field to excite the eddy current to the conductive film to be measured, and receives the composite magnetic field generated by the eddy current and the high frequency magnetic field to receive the eddy current. And an air core coil of an excitation receiving integrated type for outputting the high frequency current affected by the eddy current loss caused by The distance measuring means is provided above the air core coil, generates laser light, is incident on the surface of the conductive film via the air core of the air core coil, and receives the reflected light from the surface of the conductive film via the air core. Including laser displacement sensor A film thickness measuring apparatus, characterized in that. The method according to claim 7 or 8, The eddy current loss measuring sensor is provided to receive the high frequency current to excite the high frequency magnetic field to excite the eddy current to the conductive film to be measured, and to be wound by the eddy current excitation coil in the eddy current excitation coil, An air core receiving coil for receiving a magnetic field generated by the eddy current and the high frequency magnetic field and outputting the high frequency current affected by the eddy current loss due to the eddy current; The distance measuring means is provided above the receiving coil, generates laser light and is incident on the surface of the conductive film via the air core of the receiving coil, and receives the reflected light from the surface of the conductive film via the air core. Containing a laser displacement sensor A film thickness measuring apparatus, characterized in that. The method of claim 25, And a distance measurement error correction means for measuring the distance by driving the laser displacement sensor prior to the film thickness measurement of the conductive film, and correcting the measurement error with respect to the measurement result. The control means includes the stage moving means and the sensor moving means based on the measured distance corrected by the distance measuring error correcting means such that the eddy current loss measuring sensor scans the conductive film while maintaining a substantially constant mutual distance. To control A film thickness measuring apparatus, characterized in that. The method of claim 25, And a distance measurement error correction means for measuring the distance by driving the laser displacement sensor prior to the film thickness measurement of the conductive film, and correcting the measurement error with respect to the measurement result. The film thickness calculating means corrects the calculated film thickness value based on the measured distance corrected by the distance measuring error correcting means. A film thickness measuring apparatus, characterized in that. The method according to claim 7 or 8, The distance measuring means, And a capacitive displacement sensor having an electrode provided in proximity to the eddy current loss measuring sensor, the capacitive displacement sensor measuring the distance based on the capacitance between the electrode and the conductive film. The method of claim 29, And the measuring electrode is arranged such that its bottom face is substantially in the same plane as the bottom face of the eddy current loss measuring sensor. The method of claim 29, And the measuring electrode is formed of a high resistance material. The method of claim 29, And the measuring electrode has a ring shape for winding the eddy current loss measuring sensor. The method of claim 32, The outer diameter of the measuring electrode is substantially the same as the diameter of the region where the eddy current loss occurs due to the eddy current excited to the conductive film by the eddy current loss measuring sensor. The method of claim 32, The inner diameter of the measuring electrode is small enough that the eddy current excited in the measuring electrode by the eddy current loss measuring sensor is negligible in measurement, and the capacitance between the measuring electrode and the conductive film can be measured. And to provide the measuring electrode with a sufficient surface area. The method of claim 29, The measuring electrode is a film thickness measuring apparatus, characterized in that the thin film electrode. The method of claim 30, The said measuring electrode is comprised by the some electrode piece, The film thickness measuring apparatus characterized by the above-mentioned. The method of claim 7, wherein And a plurality of said eddy current loss measuring sensors. The method of claim 7, wherein The eddy current loss measuring sensor is provided on the side opposite to the surface on which the conductive film to be measured is formed, the surface to be etched, or the surface to be polished, and opposite to the surface on which the conductive film to be measured is formed. And a case where the substrate is provided opposite to the substrate surface, and when the substrate is disposed opposite to the surface on which the conductive film to be measured is formed and the surface on the opposite side to the surface on which the conductive film to be measured is formed. Film thickness measuring device. In the film thickness measuring method using the film thickness measuring apparatus provided with the eddy current loss measuring sensor and distance measuring means which excite an eddy current to the electrically conductive film | membrane to be measured by exciting a high frequency magnetic field, and detect the eddy current loss resulting from the said eddy current. , A distance measuring step of measuring a distance between the eddy current loss measuring sensor and the conductive film by the distance measuring means; Supplying a high frequency current to the eddy current loss measuring sensor, exciting the high frequency magnetic field to excite the eddy current to the conductive film, and the change of the impedance of the eddy current loss measuring sensor from the high frequency current output from the eddy current loss measuring sensor, the An eddy current loss measuring step of measuring a change in current value of a high frequency current or a change in phase of the high frequency current; The change of the impedance and the distance between the eddy current loss measuring sensor and the conductive film, or the change of the current value of the high frequency current and the distance between the eddy current loss measuring sensor and the conductive film, or the phase of the high frequency current A film thickness calculating step of calculating the film thickness of the conductive film based on the change of the and the distance between the eddy current loss measuring sensor and the conductive film A film thickness measuring method comprising a. The method of claim 39, The distance measuring means comprises an optical displacement sensor, And a distance measurement error correction step of measuring the distance by driving the optical displacement sensor prior to the film thickness measurement of the conductive film, and correcting the measurement error with respect to the measurement result. The film thickness calculation step includes a step of correcting the calculated film thickness value based on the measurement distance corrected by the distance measurement error correction step. The film thickness measuring method characterized by the above-mentioned. The method of claim 39, The eddy current measuring sensor includes an air core coil, The distance measuring means is provided above the air core coil, generates laser light, is incident on the surface of the conductive film via the air core of the air core coil, and receives the reflected light from the surface of the conductive film via the air core. Includes a laser displacement sensor, The distance measuring process and the eddy current loss measuring process are performed in parallel The film thickness measuring method characterized by the above-mentioned. The method of claim 39, The distance measuring means, And a capacitive displacement sensor having a measuring electrode provided in proximity to the eddy current loss measuring sensor, the capacitive displacement sensor measuring the distance based on the capacitance between the measuring electrode and the conductive film, The distance measuring process and the eddy current loss measuring process are performed in parallel The film thickness measuring method characterized by the above-mentioned. 43. The compound of any one of claims 39 to 42 wherein Prior to the eddy current loss measuring process, the high frequency current is supplied to the eddy current loss measuring sensor in a region deviating from the influence of the eddy current loss, and the impedance of the eddy current loss measuring sensor is measured from the high frequency current output from the eddy current loss measuring sensor. And a reference value measuring step of measuring the current value of the high frequency current or the phase of the high frequency current as a measurement reference value, The film thickness calculating step includes a first calculating step of calculating a film thickness of the conductive film based on a change in impedance of the eddy current loss measuring sensor, a change in current value of the high frequency current, or a change in phase of the high frequency current; And a first correction step of correcting the calculated value of the film thickness based on the measurement reference value. The film thickness measuring method characterized by the above-mentioned. The method of claim 43, In the region deviating from the influence of the eddy current, a reference conductive film serving as a measurement standard is prepared in advance with a predetermined film thickness, The reference value measuring step is a step of measuring the impedance of the eddy current loss measuring sensor, the current value of the high frequency current, or the phase of the high frequency current measured in a region where the reference conductive film is formed as the measurement reference value. The film thickness measuring method characterized by the above-mentioned. The method of claim 44, The reference conductive film is a plurality of reference conductive film formed with different film thicknesses from conductive materials having different conductivity, The reference value measuring step is a step of measuring a plurality of the measurement reference values The film thickness measuring method characterized by the above-mentioned. The method of claim 39, The film thickness measuring apparatus further includes a stage for supporting a substrate on which the conductive film is formed on a surface thereof, The eddy current loss measuring process includes a step of controlling a relative positional relationship between the stage and the eddy current loss measuring sensor so that the distance becomes substantially constant based on the measurement result of the distance measuring process. The film thickness measuring method characterized by the above-mentioned. The method of claim 39, The film thickness calculation process, A first calculating step of calculating a film thickness of the conductive film based on a change in impedance of the eddy current loss measuring sensor, a change in current value of the high frequency current, or a change in phase of the high frequency current; Correcting the film thickness value obtained in the first calculation process based on the relationship between the distance and the impedance, or the relationship between the distance and the current value of the high frequency current, or the relationship between the distance and the phase of the high frequency current. 2nd correction process Film thickness measurement method comprising a. The method of claim 39, The film thickness measuring apparatus is used in the film forming process, the etching process or the polishing process of the conductive film, The film thickness measuring method is performed in parallel with the film forming process, etching process or polishing process. The film thickness measuring method characterized by the above-mentioned. The method of claim 39, The film thickness measuring method further comprises the step of controlling the frequency of the high frequency current. The method of claim 39, The conductive film is formed on a circuit pattern including a conductive material or above the basic conductive film, The said film thickness measuring method is a process of previously calculating the film thickness value of the said circuit pattern or the said basic conductive film as an underlayer film thickness value, the film thickness of the said lower layer film thickness value and the said conductive film during or after formation of the said conductive film. Calculating a total film thickness value with the value; and subtracting the lower layer film thickness value from the calculated total film thickness value. The film thickness measuring method characterized by the above-mentioned. It is used in an eddy current loss measuring sensor that excites an eddy current to a conductive film to be measured by exciting a high frequency magnetic field and detects eddy current loss caused by the eddy current, a distance measuring means, and a film thickness measuring device including a computer. A distance measuring procedure of measuring a distance between the eddy current loss measuring sensor and the conductive film by the distance measuring means; An eddy current excitation sequence of supplying a high frequency current to the eddy current loss measuring sensor and exciting the eddy current to the conductive film by exciting the high frequency magnetic field; An eddy current loss measuring procedure for measuring a change in impedance of the eddy current loss measuring sensor, a change in current value of the high frequency current, or a change in phase of the high frequency current from the high frequency current output from the eddy current loss measuring sensor; The change of the impedance and the distance between the eddy current loss measuring sensor and the conductive film, or the change of the current value of the high frequency current and the distance between the eddy current loss measuring sensor and the conductive film, or the high frequency current A film thickness calculation procedure for calculating the film thickness of the conductive film based on the change of phase of the phase and the distance between the eddy current loss measuring sensor and the conductive film. A computer-readable recording medium having recorded thereon a program for executing the method of measuring a film thickness on the computer. The method of claim 51, wherein The film thickness measuring method further includes a distance measurement error correction procedure for measuring the distance before measuring the film thickness of the conductive film and correcting a measurement error with respect to the measurement result. The film thickness calculation order includes a step of correcting the calculated film thickness value based on the measurement distance corrected by the distance measurement error correction order. And a recording medium. The method of claim 51, wherein And the distance measurement order and the eddy current loss measurement order are executed simultaneously in parallel. The method of any one of claims 51-53, The film thickness calculation order is A first calculation procedure for calculating the film thickness of the conductive film based on a change in impedance of the eddy current loss measuring sensor, a change in current value of the high frequency current, or a change in phase of the high frequency current; Correcting the film thickness value obtained in the first calculation order based on the relationship between the distance and the impedance, or the relationship between the distance and the current value of the high frequency current, or the relationship between the distance and the phase of the high frequency current. 2nd correction procedure Recording medium comprising a.