JPH11204472A - Optical measuring device for substrate polishing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the waiting time on the side of a polishing equipment at the time of an optical measurement, and to prevent a substrate and a measurement window from being contaminated. SOLUTION: A film thickness measuring unit 3 is provided with a measurement window 35, this window 35 is made to oppose to a film thickness measurement site on the surface of a substrate W, a cleaning liquid is fed from a cleaning liquid feeding nozzle 43 to the film thickness measurement unit and cleaned, a measurement space 38 is filled with the cleaning liquid, and, in the state that the space 38 is filled with the cleaning liquid, the film thickness of a film of an object of polishing is measured. During the measuring period, a liquid for drying prevention is fed from a nozzle 52 to the whole surface of the substrate W at a prescribed timing to prevent the whole surface of the substrate W from being dried naturally during the measuring period and during the non- measuring period, the cleaning liquid (the liquid for drying prevention use) is made to feed from the nozzle 43 to the window 35 at a prescribed timing to prevent the window 35 from being dried naturally during the non-measuring period.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is provided for a substrate polishing apparatus for polishing a substrate surface, and for optically measuring a predetermined object to be measured such as a film thickness, a line width dimension, and a defect on the substrate surface. And an optical measuring device for a substrate polishing apparatus.

[0002]

2. Description of the Related Art In recent years, circuit wiring has become finer and the distance between wirings has become narrower as semiconductor devices have become more highly integrated.
Since the depth of focus becomes shallow, it is necessary to flatten the surface of the semiconductor wafer (substrate). As one means of this flattening method, a film (insulating film) formed on the substrate surface is polished to a flat and target film thickness by a substrate polishing apparatus.

In a polishing process using this substrate polishing apparatus, a top ring holds a substrate, and the surface of the substrate is pressed against a polishing cloth stretched on a turntable, and a polishing abrasive (slurry) is applied onto the polishing cloth. This is performed by rotating the turntable and the top ring (substrate) independently of each other.

[0004] This type of substrate polishing apparatus is provided with a film thickness measuring device for measuring the film thickness of a film to be polished in order to check the progress of the polishing process and the finished state. In recent years, this film thickness measurement has been performed by an optical measuring device. This optical film thickness measuring device irradiates a measuring light on a film thickness measuring portion on a substrate surface, takes in the reflected light of the measuring light at the film thickness measuring portion from the substrate surface, and measures a spectral spectrum of the reflected light. Then, the measured spectral spectrum of the reflected light is analyzed to determine the film thickness of the film to be polished formed on the substrate surface at the film thickness measurement site.

[0005] By the way, when the film thickness is measured by the above-mentioned optical film thickness measuring apparatus, if the polishing powder adheres to the surface of the substrate (the film to be polished), the polishing powder absorbs the measuring light or the measurement light. Since light is scattered, accurate measurement of the film thickness cannot be performed.

For this reason, conventionally, the entire surface of the substrate is cleaned in order to wash away polishing powder adhering to the substrate before measuring the film thickness. In addition, when the film thickness is measured with the droplets remaining on the substrate surface while the substrate surface is cleaned, the droplets on the substrate surface (the film to be polished) absorb the measurement light or scatter the measurement light. The film thickness cannot be measured accurately. Therefore,
Conventionally, the entire surface of the substrate is cleaned, and then the substrate surface is dried before measuring the film thickness.

[0007]

However, in the conventional structure, cleaning and drying of the entire surface of the substrate must be performed before measuring the film thickness. Since the time required for drying is required, there is a problem that the waiting time on the side of a polishing device such as a turntable becomes long. Not only for film thickness measurement,
Similarly, in other optical measurements such as measurement of a line width dimension and measurement of a defect, it is necessary to wash and dry the entire surface of the substrate before the measurement, and the waiting time on the polishing apparatus side is increased.

In view of this, the applicant of the present application has provided an optical measurement device such as a film thickness measurement device with a measurement window facing a partial region of the substrate surface, and the measurement window is opposed to a measurement site on the substrate surface. In the configuration, the irradiation of the measurement light on the measurement site on the substrate surface and the capture of the reflected light from the substrate surface at the measurement site are performed through the above-described measurement window. A cleaning liquid such as pure water is supplied to the measurement site to wash away the polishing powder adhering to the measurement site on the substrate surface, and after the polishing powder is washed away, a portion of the substrate surface including the measurement site facing the measurement window is removed. A gap (measurement space) between the portion area and the measurement window is filled with the cleaning liquid, and in that state, measurement light is irradiated to a measurement site on the substrate surface via the measurement window and the filled cleaning liquid, and the measurement light is applied to the measurement site. Incorporation of reflected light from the substrate surface It has proposed a technique of performing.

According to the above configuration, the polishing powder attached to the minimum necessary area on the substrate surface is washed, so that the polishing powder can be quickly washed away. Further, in order to prevent the adverse effects of the droplets after cleaning, instead of drying the cleaning portion, the cleaning space is filled with the cleaning liquid between the cleaning portion on the substrate surface and the measurement window opposed thereto, so that the processing time is reduced. A long drying process can be omitted, and the waiting time on the polishing equipment side can be shortened.

However, in the case of the above configuration, the following problem occurs. First, the abrasive powder adhering to the uncleaned part of the substrate surface naturally dries during the measurement by the optical measurement device and sticks to the substrate surface,
There is a problem that dirt that cannot be easily washed off is formed on the substrate surface.

The optical measuring apparatus is in a standby state during a non-measurement period such as a polishing process. However, dirt such as abrasive powder adhered to a measurement window during measurement or the like is naturally dried during the standby state. As a result, dirt that cannot be easily washed off is formed on the measurement window, and the accuracy of subsequent optical measurement is reduced.

The present invention has been made in view of such circumstances, and a substrate capable of preventing contamination of a substrate or a measurement window while shortening a waiting time on a polishing apparatus side during optical measurement. An object of the present invention is to provide an optical measuring device for a polishing device.

[0013]

The present invention has the following configuration in order to achieve the above object. That is, the invention according to claim 1 is provided in a substrate polishing apparatus for polishing a substrate surface, and is an optical measurement apparatus for a substrate polishing apparatus for optically measuring a predetermined measurement target on the substrate surface, Having a measurement window facing a partial region of the substrate surface, with the measurement window facing a measurement site on the substrate surface,
Measuring means for taking in reflected light from the substrate surface at the measurement site via the measurement window, and optically measuring a predetermined measurement target on the substrate surface at the measurement site based on the reflected light; and In a state facing the measurement site on the substrate surface, an optically transparent cleaning liquid is supplied to the measurement site to clean the measurement site, and a partial area of the substrate surface facing the measurement window. Cleaning liquid supply means for filling the cleaning liquid into the measurement space between the measurement window,
A substrate drying prevention unit for supplying a predetermined liquid for preventing drying to the entire surface of the substrate, and the cleaning liquid supply in a state where the measurement window is opposed to a measurement site on the substrate surface prior to measurement by the measurement unit. Means for cleaning the measurement site and filling the measurement space with the cleaning liquid, and at a predetermined timing during the measurement period by the measurement means, a liquid for preventing drying is applied to the entire surface of the substrate by the substrate drying prevention means. And control means for controlling the supply.

According to a second aspect of the present invention, there is provided the optical measuring device for a substrate polishing apparatus according to the first aspect, further comprising a measuring window drying preventing means for supplying a predetermined liquid for preventing drying to the measuring window. At a predetermined timing during a non-measurement period in which the measurement by the measurement unit is not performed, the control unit controls the measurement window drying prevention unit to supply a liquid for preventing drying to the measurement window by the measurement window drying prevention unit. It is assumed that.

According to a third aspect of the present invention, in the optical measuring device for a substrate polishing apparatus according to the second aspect, the cleaning liquid supply means supplies a cleaning liquid to the measurement site and the measurement window. The measurement window also serves as a drying prevention means, and, further comprising a liquid amount switching means for switching the amount of the cleaning liquid flowing out from the cleaning liquid supply means, the control means,
According to a predetermined procedure, switching control of the outflow amount of the cleaning liquid from the cleaning liquid supply means is performed.

[0016]

The operation of the first aspect of the invention is as follows. When optically measuring a predetermined measurement target on the substrate surface at a measurement site on the substrate surface by the measurement unit, prior to the measurement, the control unit sets the measurement window of the measurement unit to face the measurement site of the measurement target. In this state, the cleaning liquid supply unit is controlled to supply the cleaning liquid to the measurement site on the substrate surface, thereby cleaning the measurement site, and at the same time, between the measurement window and the partial area of the substrate surface facing the measurement window. Fill the measuring space with the washing liquid. In that state, measurement by the measuring means, that is, reflected light from the substrate surface at the measurement site to be measured is taken in through the cleaning liquid filled in the measurement window and the measurement space, and the substrate surface at the measurement site based on the reflected light is taken. An optical measurement of the above predetermined measurement object is performed. Also, the control means controls the substrate drying prevention means at a predetermined timing during the measurement period in which the measurement is being performed by the measurement means to supply a liquid for preventing drying to the entire surface of the substrate, and to control the surface of the substrate. Of these, natural drying of the portion not cleaned by the cleaning liquid supply means during the measurement period is prevented.

According to the second aspect of the present invention, the control means controls the measurement window drying prevention means at a predetermined timing during a non-measurement period in which measurement by the measurement means is not performed, thereby preventing the measurement window from drying. To prevent spontaneous drying of the measurement window during the non-measurement period.

According to the third aspect of the present invention, the cleaning liquid supply means is configured to supply the cleaning liquid to the measurement site and the measurement window, and also serves as the measurement window drying prevention means.
The control unit controls the switching of the amount of the cleaning liquid flowing out from the cleaning liquid supply unit to the measurement site and the measurement window in accordance with a predetermined procedure. For example, when a cleaning liquid is supplied to a measurement site for cleaning the measurement site, the liquid is caused to flow out with a relatively large amount of liquid, and the measurement site is quickly and reliably cleaned. On the other hand, since the purpose of supplying the cleaning liquid (liquid for preventing drying in this case) to the measurement window is to prevent drying of the measurement window, the liquid may be discharged with a relatively small liquid discharge amount. In this way, by switching the outflow amount of the liquid as needed, the useless amount of the cleaning liquid can be reduced.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view showing a schematic configuration of an entire substrate polishing apparatus provided with a film thickness measuring device, which is one of the optical measuring devices for the substrate polishing device. FIG.
FIG. 4 is a schematic configuration diagram of an example of an optical system of a film thickness measuring device, FIG. 4 is an enlarged vertical sectional view near a measurement window, and FIG. 5 is a block diagram illustrating a configuration of a control system of the device.

This embodiment includes a turntable 1, a top ring 2, a film thickness measuring device 3, a cleaning liquid supply mechanism 4, a substrate drying prevention mechanism 5, and the like.

The turntable 1 is integrally rotatably connected to an upper end of a rotating shaft 11 which is rotatably provided around a vertical axis J by a rotating mechanism (not shown) having a motor or the like. . A polishing cloth 12 is stretched on the upper surface of the turntable 1, and a turntable ring 13 is provided on an outer peripheral portion of the turntable 1 for preventing scattering of polishing abrasive liquid (slurry) or the like. A polishing abrasive liquid nozzle 14 is provided above the turntable 1 so that the polishing abrasive liquid can be supplied from the polishing abrasive liquid nozzle 14 onto the polishing cloth 12 on the upper surface of the turntable 1. The supply and the stop of the polishing liquid from the polishing liquid nozzle 14 are performed by opening and closing an open / close valve (not shown).

The top ring 2 is integrally rotatably connected to the tip of the rotation support shaft 21 and is configured to rotate around a vertical axis P. The rotation support shaft 21 is
The support arm 22 is rotatably supported on the distal end side and vertically movable.

The rotation support shaft 21 is rotated about a vertical axis P by a rotation mechanism (not shown) provided with a motor and the like provided in the support arm 22. A rod of a top ring cylinder (not shown) provided in the support arm 22 is connected to the upper end of the rotation support shaft 21, and the rotation of the rotation support shaft 21 is raised and lowered by the expansion and contraction of the rod. 2
Can be pressed against the turntable 1 with a constant pressure.

The base end of the support arm 22 is rotated vertically (not shown) by a rotating mechanism (not shown) having a motor or the like.
The support arm 22 is configured to be rotatable around, and the entire support arm 22 is swung in the horizontal direction about the axis R as a fulcrum. Thereby, the top ring 2 can be moved horizontally between the upper part of the turntable 1 and the side of the turntable 1 which is separated from the upper part of the turntable 1. Further, in order to separate the turntable 1 (polishing cloth 12) and the substrate W held by the top ring 2 when the substrate W is loaded or unloaded, a well-known uniaxial driving mechanism such as a ball screw is used. The support arm 22 is configured to be able to move up and down by a lifting mechanism (not shown) so that the top ring 2 can be moved up and down.

The film thickness measuring device 3 is disposed at a predetermined position on the side of the turntable 1 and within a movable range of the top ring 2. As shown in FIG. 3, the film thickness measuring device 3 includes an illumination optical system 30, an imaging optical system 31, a spectral unit 33, a monitoring optical system 34, and the like housed in a housing 3a.

The illumination optical system 30 includes a light source 3 for emitting measurement light.
0a, condenser lenses 30b, 30e, aperture stop 30
c, a field stop 30d and the like.

The image forming optical system 31 includes an objective lens 31a, a half mirror 31c for superimposing measurement light from the illumination optical system 30 on the optical path of the image forming optical system 31, an image forming lens 31d, and the like. Note that reference numeral 31b in the figure indicates a pupil position, and reference numeral 35 indicates a measurement window formed of a glass plate or the like facing a partial region of the substrate W.

The image of the surface of the substrate W in the vicinity of the predetermined film thickness measurement site is reflected by the reflecting optical system 32 by the imaging optical system 31.
It is enlarged and displayed near a. The reflecting mirror 32a has a pinhole 3 at a position corresponding to the imaging position of the imaging optical system 31.
2b is open.

The measurement light emitted from the light source 30a is reflected toward the surface of the substrate W by the half mirror 31c, and is irradiated on the surface of the substrate W via the objective lens 31a and the measurement window 35. The reflected light reflected at the film thickness measurement site on the surface of the substrate W passes through the measurement window 35, the imaging optical system 31, and the pinhole 32 b of the reflection mirror 32 a, and then enters the spectroscopic unit 3.
3

The spectroscopy unit 33 includes a diffraction grating 33a for dispersing light reflected from a film thickness measurement site (point) on the surface of the substrate W conjugate with the pinhole 32b, and a light for detecting a spectrum from the diffraction grating 33a. And a detector 33b. As the diffraction grating 33a, for example, a flat field type diffraction grating that forms an image of a spectrum on a plane is used. As the photodetector 33b, for example, a photodiode array or a CCD is used. In addition, the spectroscopic unit 33 may be configured by a photodetector such as a diffraction grating with a sweep mechanism or a photomultiplier tube.

The monitor optical system 34 forms an enlarged image near the film thickness measurement site on the surface of the substrate W formed near the reflecting mirror 32a at the image forming position 34b by the relay lens 34a. It is used for confirmation of a film thickness measurement site on the surface of W and focusing.

On the surface of the substrate W, a plurality of thin films including the uppermost film to be polished are formed in layers. The measurement light applied to the surface of the substrate W is reflected at the upper surface of the film to be polished to be measured, at the interface between the films, at the interface between the lowermost film and the surface of the substrate W, and the like. Reflected light interfere with each other and are taken into the spectral unit 33. Since the degree of interference of each reflected light depends on the refractive index, film thickness and light wavelength of the substrate W and each film, the spectroscopic unit 33 analyzes the spectral spectrum of the reflected light to form on the surface of the substrate W. The thickness of the film to be polished, which is the measured object to be measured, can be obtained. The film thickness calculating unit 33c includes a photodetector 33b.
The thickness of the film to be polished, which is the object to be measured, is determined based on the output from.

As shown in FIG. 2, the housing 3a of the film thickness measuring device 3 is mounted and supported on an XY stage 36, and can move the measuring window 35 arbitrarily in the horizontal two-dimensional (XY) direction. The thickness of a desired thickness measurement site on the surface of the substrate W can be measured. The XY stage 36 and the housing 3a of the film thickness measuring device 3 are
The film thickness measuring device 3 and the substrate W
It is configured such that focusing can be performed by bringing the surface into and out of contact.

The cleaning liquid supply mechanism 4 includes a cleaning liquid supply source 41, a cleaning liquid supply pipe 42, a cleaning liquid supply nozzle 43, an on-off valve 4
4. It is provided with a flow control valve 45 and the like.

The cleaning liquid supply nozzle 43 is disposed on the side of the measurement window 35, and the measurement window 35 is placed close to and opposed to the film thickness measurement site on the surface of the substrate W, and is optically supplied with pure water or the like. A transparent cleaning liquid is supplied to the film thickness measurement site to clean the film thickness measurement site, and the substrate W facing the measurement window 35 is cleaned.
The gap (measurement space) 38 between a partial area of the surface of the surface and the measurement window 35 can be filled with the cleaning liquid. The cleaning liquid flowing out of the cleaning liquid supply nozzle 43 is also supplied to the measurement window 35.

The supply of the cleaning liquid to the cleaning liquid supply nozzle 43 is performed from a cleaning liquid supply source 41 via a cleaning liquid supply pipe 42. The on-off valve 44 and the flow control valve 45 are interposed in the cleaning liquid supply pipe 42. By switching the opening and closing of the on-off valve 44, the supply (outflow) of the cleaning liquid from the cleaning liquid supply nozzle 43 and the stop thereof are switched. Further, by switching the flow rate of the flow control valve 45, the cleaning liquid supply nozzle 43 is switched.
The outflow amount of the cleaning liquid from the nozzle can be arbitrarily switched.

The substrate drying prevention mechanism 5 is provided near the film thickness measuring device 3. The substrate drying prevention mechanism 5 of this embodiment includes a ring-shaped main body 5 supported by an apparatus frame F.
1, a large number of nozzles 52 are provided along the circumferential direction. Each nozzle 52 is configured to spray a liquid for preventing drying such as pure water in a mist form toward a wide area of the surface of the substrate W, and apply the liquid for preventing drying to the entire surface of the substrate W. It can be supplied. The supply of the liquid to each nozzle 52 is performed from a liquid supply source 55 via a liquid supply path 53 provided in the main body 51 and a liquid supply pipe 54. The liquid supply pipe 53 has an on-off valve 5
6 is interposed, and by switching between opening and closing of the on-off valve 56, it is possible to switch between the supply of the liquid from each nozzle 52 and the stop thereof.

As shown in FIG. 5, an opening / closing valve P for switching between the supply of the polishing liquid from the polishing liquid nozzle 14 and the stop thereof.
CB opening / closing control, drive control of a rotation mechanism RM1 for rotating the rotation shaft 11 (turntable 1) around the axis J, drive of a rotation mechanism RM2 for rotating the rotation support shaft 21 (top ring 2) about the axis P. Control, top ring cylinder T
RS drive control, rotation mechanism RM that swings entire support arm 22 around R (moves top ring 2 horizontally)
3, the drive control of the lifting mechanism UDM for raising and lowering the support arm 22 (top ring 2), the ON / OFF control of the light source 31a of the film thickness measuring device 3, the calculation command to the film thickness calculator 33c, the XY stage 36 Drive control, lifting mechanism 37
Drive control, open / close control and flow rate control of the open / close valve 44 and the flow rate control valve 45 of the cleaning liquid supply mechanism 4, and the substrate drying prevention mechanism 5
The control of the entire apparatus such as the opening / closing control of the opening / closing valve 56 is performed by the controller 6. This controller 6
Is configured by a microcomputer, and controls each unit to perform a polishing process and a film thickness measurement process according to a program created in advance, as described later.

Next, the operation of the embodiment apparatus having the above configuration will be described. In the polishing process, the top ring 2 holds the substrate W in a horizontal posture so that the surface of the substrate W faces downward, and the polishing cloth 1 stretches the surface of the substrate W on the turntable 1.
2 and the polishing liquid is caused to flow from the polishing liquid nozzle 14 onto the polishing cloth 12 so that the turntable 1 and the top ring 2
This is performed by independently rotating the (substrate W).

During the polishing process, the controller 6 opens the opening / closing valve 44 of the cleaning liquid supply mechanism 4 at a predetermined timing because the film thickness is not measured by the film thickness measuring device 3 during the non-measurement period. Then, the cleaning liquid is supplied to the measurement window 35 to prevent the measurement window 35 from spontaneously drying during the non-measurement period.

The cleaning liquid supply nozzle 43 is connected to the measuring window 3
The above-mentioned timing may be determined so that the supply of the cleaning liquid to 5 is always performed during the non-measurement period, or may be determined intermittently at predetermined time intervals.

Further, when cleaning the film thickness measuring portion in the film thickness measurement described later, the amount of the cleaning liquid flowing out from the cleaning liquid supply nozzle 43 is required to quickly and reliably clean the film thickness measuring portion. It is preferable to adjust to a relatively large outflow. On the other hand, when the cleaning liquid is supplied to the measurement window 35, the measurement window 35 can be prevented from being dried, that is, the measurement window 3
5 is sufficient to spread the cleaning liquid over the entirety, and supplying the cleaning liquid to the measurement window 35 with the same amount of liquid flowing out as when cleaning the film thickness measurement site is an excessive supply of the cleaning liquid. It becomes useless use. Therefore, when supplying the cleaning liquid to the measurement window 35, the flow control valve 45 of the cleaning liquid supply mechanism 4 is adjusted to reduce the amount of liquid flowing out from the cleaning liquid supply nozzle 43, for example, when cleaning the film thickness measurement site. It is preferable to adjust the amount of liquid outflow to be smaller than the amount of liquid outflow. This allows
The useless amount of the cleaning liquid can be reduced.

The measurement of the thickness of the film to be polished is performed as follows. The rotation of the turntable 1 and the top ring 2 is stopped, and the substrate W
Is released, and the top ring 2 is raised above the turntable 1. Next, the support arm 22
When the top ring 2 reaches a predetermined position above the film thickness measuring device 3, the swing of the support arm 22 is stopped. In this embodiment, in order to ensure that the liquid from each nozzle 52 of the substrate drying prevention mechanism 5 is supplied to the entire surface of the substrate W, the rotation axis P of the top ring 2 is set at the predetermined position. At a position corresponding to the center of the central opening of the main body 51.

Then, the top ring 2 holding the substrate W is lowered by lowering the support arm 22 so that the measurement space 38 becomes a predetermined distance, for example, the film thickness measurement device 3.
The lowering of the top ring 2 is stopped at a predetermined height position such that the focal point of the optical system is at a distance matching the surface of the substrate W. At this time, the measurement window 35 is located at a predetermined height position.

Next, a preparatory operation for film thickness measurement at the film thickness measurement site is performed. First, the film thickness measuring device 3 is moved in the horizontal two-dimensional direction so that the measurement window 35 faces a film thickness measurement site preset on the surface of the substrate W. Next, the opening / closing valve 44 of the cleaning liquid supply mechanism 4 is opened to supply (flow) the cleaning liquid from the cleaning liquid supply nozzle 43. At this time, since the measurement window 35 and the film thickness measurement site on the surface of the substrate W are closely opposed to each other, the cleaning liquid from the cleaning liquid supply nozzle 43 disposed on the side of the measurement window 35 The polishing powder supplied to the film thickness measurement site on the surface of the substrate W and adhering to the film thickness measurement site and the vicinity thereof can be washed away. Also, as described above, when cleaning the film thickness measurement site,
The flow rate control valve 45 of the cleaning liquid supply mechanism 4 is adjusted to quickly and surely clean the film thickness measurement site, and the amount of the cleaning liquid flowing out from the cleaning liquid supply nozzle 43 is adjusted to a relatively large amount. ing. While the supply of the cleaning liquid from the cleaning liquid supply nozzle 43 is continued, the state where the measurement space 38 is filled with the cleaning liquid is maintained. In this state, the film thickness measuring device 3
If the focus of the optical system is not focused on the film thickness measurement site on the surface of the substrate W, focusing is performed.

After the above preparation operation, the film thickness of the film to be polished at the film thickness measurement site is measured while the measurement space 38 is filled with the cleaning liquid.

In order to maintain the state in which the measurement space 38 is filled with the cleaning liquid, the supply amount of the cleaning liquid supplied to the measurement space 38, that is, the outflow amount of the cleaning liquid from the cleaning liquid supply nozzle 43 is determined by the film thickness measurement. It is not necessary to have a large outflow as in the case of washing a site, but a smaller outflow may be used. Therefore, for example, first, during a predetermined cleaning time, the cleaning liquid is supplied from the cleaning liquid supply nozzle 43 with a large outflow to clean the film thickness measurement site. Until the measurement of the film thickness of the cleaning liquid is completed, the cleaning liquid is supplied from the cleaning liquid supply nozzle 43 with a small outflow amount, and the flow control valve 45 is adjusted and controlled so as to maintain the state in which the measurement space 38 is filled with the cleaning liquid. The amount of use can be reduced. After the cleaning of the film thickness measurement site, if the cleaning space remains in the measurement space 38 due to the surface tension of the cleaning solution and the measurement space 38 is filled with the cleaning solution, the cleaning solution is finished after the cleaning of the film thickness measurement site. The supply of the cleaning liquid from the supply nozzle 43 may be stopped.

When the film thickness measurement sites are set at a plurality of positions on the surface of the substrate W, the above operation is performed for each film thickness measurement site, and the film to be polished at each film thickness measurement site is determined. The film thickness is measured sequentially.

Here, for example, the measurement period is from the start of the preparatory operation for the film thickness measurement to the film thickness measurement site to be measured first to the end of the film thickness measurement to the film thickness measurement site to be measured finally. Then, during this measurement period, the controller 6 opens the on-off valve 56 of the substrate drying prevention mechanism 5 at a predetermined timing to supply the liquid for preventing drying to the entire surface of the substrate W, Prevents natural drying of the entire surface during the measurement period.

The supply of the liquid from the nozzles 52 to the entire surface of the substrate W may be determined so as to be performed at all times during the measurement period, or may be performed intermittently at predetermined time intervals. The timing may be determined as described above.
When the liquid is intermittently supplied, control may be performed so that the liquid is supplied to the entire surface of the substrate W at the timing of measuring the film thickness. When the supply of the liquid has an effect on the measurement of the film thickness, for example, while moving the film thickness measuring device 3 in the horizontal two-dimensional direction for the alignment between each film thickness measuring part and the measuring window 35, Substrate W
The liquid may be supplied to the entire surface of the substrate.

When the film thickness measurement at all the film thickness measurement sites is completed, the support arm 22 is raised and the top ring 2 holding the substrate W is raised. Thereafter, if the polishing process is performed again on the substrate W, the support arm 22 is swung in the horizontal direction, the top ring 2 (substrate W) is moved above the turntable 2, and the top ring 2 is moved. While being lowered, the substrate W is pressed against the turntable 1 at a predetermined pressure, and the polishing process is performed as described above.

The non-measurement period in which the film thickness measurement by the film thickness measurement device 3 is not performed is not limited to the polishing process. For example, the film thickness measurement by the film thickness measurement device 3 may be performed even when the device is in an idle state. It is a non-measurement period because it has not been performed. Therefore, even when the apparatus is in a halt state, the controller 6 causes the cleaning liquid supply mechanism 4 to supply the cleaning liquid to the measurement window 35 at a predetermined timing, thereby preventing the measurement window 35 from being naturally dried.

As described above, according to this embodiment, the waiting time on the side of the polishing equipment such as the turntable 1 when measuring the film thickness can be shortened, and the substrate W during the measurement period can be shortened.
Can be prevented from being naturally dried on the entire surface of the substrate W, and the inconvenience of forming dirt on the surface of the substrate W that the polishing powder sticks to the surface of the substrate W and cannot be easily washed off can be prevented.

Further, natural drying of the measurement window 35 during the non-measurement period can be prevented, and dirt that cannot be easily washed off can be removed.
Can be prevented.

Further, the outflow amount of the cleaning liquid from the cleaning liquid supply mechanism 4 can be switched as required, and the useless amount of the cleaning liquid can be reduced.

Next, a modification of the above embodiment will be introduced. The substrate drying prevention mechanism 5 of the above-described embodiment is configured to supply the liquid from the nozzle 52 to the entire surface of the substrate W in the form of a mist. May be configured.

In the above embodiment, the cleaning liquid supply mechanism 4 serves as both the cleaning liquid supply means and the measurement window drying prevention means in the present invention, but only supplies the liquid for preventing drying to the measurement window 35. The mechanism may be configured to be provided separately from the cleaning liquid supply mechanism 4.

In the above embodiment, the positioning operation for causing the measurement window 35 to face a desired film thickness measurement site on the surface of the substrate W is performed by moving the film thickness measurement device 3 in the two-dimensional horizontal direction. However, for example, the film thickness measuring device 3 is configured to be able to move only in the horizontal one-dimensional direction along the radius of the surface of the substrate W held by the top ring 2, and the film thickness measuring device 3 side The movement of the top ring 2 (substrate W) about the axis P by the movement in the horizontal one-dimensional direction causes the measurement window 3 to move.
It is also possible to perform a positioning operation for causing the film 5 to face a desired film thickness measurement site on the surface of the substrate W.

In the above embodiment, the substrate W is
The film thickness measurement process is performed in a state where the substrate W is held. For example, when a substrate holding stage for holding the substrate W is provided on the film thickness measurement device 3 side and the film thickness is measured, a top ring is used. The film thickness measurement process may be performed in a state where the substrate W is transferred from Step 2 to the substrate holding stage and the substrate W is held on the substrate holding stage.

In the above embodiment, the controller 6 controls the film thickness measuring device 3 to automatically measure the film thickness. However, the controller 6 controls the film thickness measuring device 3 when the measuring space 38 is filled with the cleaning liquid. The thickness measurement itself by 3 may be performed manually by an operator.

It should be noted that the film thickness measuring portion is not particularly determined, and any portion on the surface of the substrate W may be measured as a film thickness measuring portion, or may be opposed to a predetermined film thickness measuring portion. For example, when the measurement window 35 is provided at the position, the positioning operation for making the measurement window 35 face a specific film thickness measurement site becomes unnecessary. Therefore, in such a case, the XY stage 36 can be omitted. Also, when measuring the film thickness at a plurality of film thickness measurement sites,
If the same number of film thickness measurement devices 3 as the film thickness measurement sites are provided at positions facing the film thickness measurement sites corresponding to the respective film thickness measurement devices 3, the measurement windows of each film thickness measurement device 3 can be obtained. 35
No positioning operation is required to face the film to the corresponding film thickness measurement site. In this case, since the film thickness measurement at a plurality of film thickness measurement sites can be performed simultaneously and in parallel, the film thickness measurement at a plurality of film thickness measurement sites can be performed in comparison with the case where the film thickness measurement is sequentially performed by one film thickness measurement device 3. The time required for the film thickness measurement processing can be reduced.

The film thickness measuring device 3 exemplified in the above embodiment is
The optical axis from the objective lens 31a to the diffraction grating 33a is set in the vertical direction, and the film thickness measuring device 3 is enlarged in the vertical direction. For example, as shown in FIG. Optical path deflecting member 70 such as a plane mirror
And the optical axis KJT on the distal end side of the optical path deflecting member 70
Is set in the vertical direction, the optical axis KJB from the optical path deflecting member 70 to the diffraction grating 33a is set in the horizontal direction, and the thickness between the measurement window 35 and the objective lens 31a is reduced vertically. May be used. By using the film thickness measuring device 3 having such a configuration, the measurement window 35 can be made to enter from the side below the surface of the substrate W. For example, the polishing process is interrupted or the polishing process is terminated. When the top ring 2 holding the substrate W is lifted above the turntable 1, the measurement by the film thickness measurement device 3 is performed in the space between the turntable 1 and the surface of the substrate W held by the top ring 2. The window 35 can be made to enter from the side to measure the film thickness of the film thickness measurement site on the surface of the substrate W held by the top ring 2 above the turntable 1.

As the substrate drying prevention mechanism 5 when the film thickness measuring device 3 having the structure shown in FIG. 6 is used, for example, a liquid for preventing drying is supplied to the entire surface of the substrate W as shown in FIG. By disposing the nozzle 57 below the film thickness measuring device 3 entering below the surface of the substrate W, the measurement window 35 of the film thickness measuring device 3 can be horizontally and two-dimensionally arranged with respect to the surface of the substrate W. It can be moved freely. However, when the liquid is supplied from the nozzle 57 in a state where the film thickness measuring device 3 has entered below the surface of the substrate W, the housing 3a of the film thickness measuring device 3
In some cases, the liquid from the nozzle 57 is not supplied to a part of the surface of the substrate W because of the obstruction. In such a case, the nozzle 5 for supplying the liquid for preventing drying to the surface of the substrate W is used.
8 may be provided on the housing 3a of the film thickness measuring device 3.

As described above, with the top ring 2 holding the substrate W raised above the turntable 1, the position between the turntable 1 and the surface of the substrate W held on the top ring 2 is increased. The measurement window 35 of the film thickness measuring device 3 is made to enter the space from the side, and the film thickness of a predetermined film thickness measurement site on the surface of the substrate W held by the top ring 2 is measured above the turntable 1. In this case, the nozzle 57 may be configured to be horizontally movable between the upper part of the turntable 1 and the standby position on the side of the turntable 1.

In the above embodiment, the case where the film thickness of the film to be polished is optically measured has been described as an example. However, for example, other measurement objects such as line width dimension measurement and defect measurement can be used. When a measuring device for optically performing measurement is provided in the substrate polishing apparatus, the present invention can be similarly applied to the measurement of each measurement object.

[0066]

As is apparent from the above description, according to the first aspect of the present invention, the measuring means is provided with a measuring window, the measuring window is opposed to the measuring site on the substrate surface, and the cleaning liquid is supplied to the substrate. Supply to the measurement site on the surface, clean the measurement site, fill the measurement space between the measurement window with the partial area of the substrate surface facing the measurement window, and perform optical measurement in that state. Therefore, the waiting time on the side of the polishing equipment at the time of optical measurement can be shortened as compared with the conventional configuration. Then, at a predetermined timing during the measurement period in which the measurement by the measurement means is performed, the liquid for preventing drying is supplied to the entire surface of the substrate, so that natural drying during the measurement period for the entire surface of the substrate is performed. Thus, it is possible to prevent the inconvenience of forming dirt on the substrate surface that cannot be easily washed off due to the polishing powder sticking to the substrate surface.

According to the second aspect of the present invention, the liquid for preventing drying is supplied to the measurement window at a predetermined timing during the non-measurement period in which the measurement by the measurement means is not performed. Also, natural drying of the measurement window during the non-measurement period can be prevented, and the inconvenience of forming stains that cannot be easily washed off on the measurement window can also be prevented.

According to the third aspect of the present invention, since the cleaning liquid supply means is configured to supply the cleaning liquid to the measurement site and the measurement window and also serves as the measurement window drying prevention means, the number of parts of the apparatus is reduced. can do. In addition, the amount of the outflow of the cleaning liquid from the cleaning liquid supply unit is configured to be switchable, and the control unit is configured to control the switching of the amount of the outflow of the cleaning liquid from the cleaning liquid supply unit according to a predetermined procedure. In addition, the outflow amount of the cleaning liquid from the cleaning liquid supply means can be switched as needed, and the useless amount of the cleaning liquid can be reduced.

[Brief description of the drawings]

FIG. 1 is a plan view showing a schematic configuration of an entire substrate polishing apparatus provided with a film thickness measuring device which is one of the optical measuring devices for the substrate polishing device.

FIG. 2 is a longitudinal sectional view of the entire substrate polishing apparatus.

FIG. 3 is a schematic configuration diagram of an example of an optical system of a film thickness measuring device.

FIG. 4 is an enlarged vertical sectional view near a measurement window.

FIG. 5 is a block diagram showing a configuration of a control system of the apparatus.

FIG. 6 is a longitudinal sectional view showing a configuration of a main part of a modification of the film thickness measuring apparatus.

[Explanation of symbols]

 1: Turntable 2: Top ring 3: Film thickness measuring device 4: Cleaning liquid supply mechanism 5: Substrate drying prevention mechanism 6: Controller 35: Measurement window 38: Measurement space 45: Flow control valve W: Substrate

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hitoshi Atsuta 4-chome Tenjin Kitamachi 1-chome, Horikawa-dori Teranouchi, Kamigyo-ku, Kyoto Dainippon Screen Mfg. Co., Ltd. (72) Inventor Noriyuki Kondo Kamigyo, Kyoto-shi 4-chome Tenjin, Horikawa-dori Terunouchi-ku 1 Kitamachi 1 Dainippon Screen Mfg. Co., Ltd.

Claims (3)

[Claims] 1. An optical measuring device for a substrate polishing apparatus, provided in a substrate polishing apparatus for polishing a substrate surface, for optically measuring a predetermined object to be measured on the substrate surface, comprising: In the state where the measurement window is opposed to the measurement site on the substrate surface, captures reflected light from the substrate surface at the measurement site via the measurement window, based on the reflected light. A measuring unit for optically measuring a predetermined measurement target on the substrate surface at the measurement site; and an optically transparent cleaning liquid applied to the measurement site while the measurement window is opposed to the measurement site on the substrate surface. A cleaning liquid supply unit that supplies the cleaning liquid to the measurement area between the measurement window and a part of the substrate surface facing the measurement window. To prevent drying Substrate drying prevention means for supplying a predetermined liquid, and prior to measurement by the measurement means, while the measurement window is opposed to the measurement area on the substrate surface, the cleaning liquid supply means cleans the measurement area. Control means for filling the measurement space with a cleaning liquid, and controlling the substrate drying prevention means to supply a liquid for preventing drying over the entire surface of the substrate at a predetermined timing during the measurement period by the measurement means. An optical measuring device for a substrate polishing apparatus, comprising: 2. The optical measurement device for a substrate polishing apparatus according to claim 1, further comprising: a measurement window drying prevention unit that supplies a predetermined liquid for preventing drying to the measurement window, wherein the control unit includes the measurement unit. At a predetermined timing during a non-measurement period in which measurement is not performed by the measurement window, wherein the measurement window drying prevention means controls the supply of a liquid for preventing drying to the measurement window. apparatus. 3. The optical measurement device for a substrate polishing apparatus according to claim 2, wherein the cleaning liquid supply unit is configured to supply a cleaning liquid to the measurement site and the measurement window, and the measurement window drying prevention unit. And a liquid amount switching means for switching a liquid outflow amount of the cleaning liquid from the cleaning liquid supply means, wherein the control means determines a liquid outflow amount of the cleaning liquid from the cleaning liquid supply means in accordance with a predetermined procedure. An optical measuring device for a substrate polishing apparatus, which performs switching control.