JP3297279B2 - Surface treatment end point detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a processing liquid (etching liquid, developing liquid, etc.) supplied to the surface of a substrate such as a glass substrate for a liquid crystal display or a semiconductor wafer to remove an object formed on the substrate surface. In the surface treatment for removing the layer (such as an etching treatment or a development treatment), a curtain of the same liquid as the treatment liquid is formed in a measurement region between the measurement window provided to face the substrate surface and the substrate surface. The present invention relates to a surface treatment end point detecting device for detecting the end point of surface treatment, and more particularly to an improved technique of a liquid curtain forming means provided in the surface treatment end point detecting device.

[0002]

2. Description of the Related Art As a conventional surface treatment end point detecting apparatus of this type, there is, for example, an apparatus proposed by the present applicant in Japanese Patent Application Laid-Open No. 5-322515.

The conventional apparatus disclosed in this publication irradiates measurement light in a predetermined wavelength band onto a substrate surface and reflects the measurement light reflected from the substrate surface (the surface of the surface layer formed on the substrate surface or the surface layer). Interference light of each reflected light from the interface of each film constituting the interface, the interface between the lowermost layer of the surface layer and the substrate surface)
The amount of reflected light is measured, and the change in the amount of reflected light is analyzed to detect the end point of the etching process.

Further, in this conventional apparatus, during the etching process, the processing liquid is supplied while rotating or reciprocating the substrate in the horizontal direction. As a result, a pulsating flow or bubbles of the processing liquid are generated on the substrate surface. Teaches that if the pulsating flow or bubbles are present in the measurement light beam or the reflected light beam, the measurement light beam or the reflected light beam is scattered, and a measurement error occurs, thereby lowering the accuracy of end point detection.

As one of effective means for solving such inconveniences, a conventional apparatus employs a so-called liquid curtain forming means (liquid curtain method). The liquid curtain forming means is provided to face the substrate surface, and transmits a measurement light beam to irradiate the substrate, and a measurement window (glass plate) for transmitting and taking in a reflected light beam from the substrate surface.
By filling the measurement area between the substrate surface and the measurement area with the same liquid as the processing liquid, it is possible to prevent the pulsating flow from entering the measurement area from the outside, and to prevent air bubbles from entering the measurement area from the outside and the inside of the measurement area. The generation of bubbles is suppressed.

Further, the conventional liquid curtain forming means is designed to fill the space between the measuring window and the substrate surface with the processing liquid, the distance between the measuring window and the substrate surface, the amount of liquid flowing out of the liquid curtain forming means, and the like. The reference value is experimentally determined, and the measurement window is fixedly installed at a position where the distance between the measurement window and the substrate surface becomes the reference distance with respect to the substrate set in the etching device (surface treatment device). The processing liquid is discharged from the liquid curtain forming means at a reference liquid flow amount to form a liquid curtain.

[0007]

However, the prior art having such a structure has the following problems. That is, in the conventional liquid curtain forming means, it is possible to prevent the pulsating flow from entering the measurement area, but there is a case where bubbles exist in the measurement area, which causes a measurement error. Was.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and it is possible to prevent a pulsating flow from entering a measurement region, and to prevent a bubble from entering a measurement region and generate air bubbles in a measurement region. It is an object of the present invention to provide a surface treatment end point detecting device provided with a liquid curtain forming means capable of suitably suppressing the above.

[0009]

Means for Solving the Problems The present inventor investigated the cause of the presence of bubbles in the measurement area with the conventional apparatus, and found out that the cause was as follows.

That is, for example, in an apparatus for etching a glass substrate for a liquid crystal display, an etching process is performed while the substrate is supported by a group of rollers and reciprocated in a horizontal direction. As a result, the horizontal plane of the substrate surface on which the substrate is supported deviates from the originally planned horizontal plane, and the distance between the measurement window fixedly installed and the actual substrate surface with respect to the originally planned horizontal plane becomes the reference distance. It is considered that air bubbles exist in the measurement region due to the absence of the air bubbles.

For example, when the distance between the measurement window and the substrate surface is wider than the reference distance, the processing area for the liquid curtain is not sufficiently filled in the measurement area, and bubbles enter the measurement area from outside. On the other hand, if the distance between the measurement window and the substrate surface is narrower than the reference distance, the processing liquid flowing out of the liquid curtain hits the substrate surface, and the water pressure on the substrate surface increases. It is conceivable that bubbles are generated at the time.

Therefore, the present inventor tried to adjust the distance between the measurement window and the surface of the substrate by manually changing the mounting position of the measurement window as needed, and to adjust the distance between the measurement window and the surface of the substrate. It is difficult to adjust the temperature, and in this type of etching equipment, etc., organic solvents and acids are used. Manually adjusting the distance between the measurement window and the substrate surface may pose a danger to the human body. Furthermore, even if the distance between the measurement window and the substrate surface can be adjusted manually, it is difficult to predict when the mechanical degradation will occur, and the distance between the measurement window and the substrate surface must be adjusted in advance. Is difficult, and as a result, it is inevitable to discharge a substrate which becomes a processing failure.

Further, for example, a glass substrate for a liquid crystal display has a constant thickness so far, but substrates having different thicknesses have been manufactured due to recent technical improvements and the like. When substrates having different thicknesses are successively put into a surface treatment device such as an etching device, the distance between the measurement window and the substrate surface varies for each substrate having a different thickness, for the same reason as described above. It is predicted that bubbles enter the measurement area or generate bubbles.

In this case, it is considered that it is not so difficult to manually adjust the distance between the measurement window and the substrate surface to the reference distance because the thickness of the substrate to be put into the surface treatment device or the like is known in advance. Since the adjustment may be performed before the substrate is put into the surface treatment apparatus, it is considered that the processing failure of the substrate can be prevented. However, the danger to the human body has not been eliminated before, and it is troublesome to adjust the distance between the measurement window and the substrate surface for each substrate having a different thickness. In addition, in consideration of the above-described deterioration of the machine, it is considered that generation of bubbles and the like cannot always be suppressed.

Further, the present inventor investigated and investigated the cause of the inconvenience such as the generation of the above-mentioned air bubbles, and found that the distance between the measurement window and the substrate surface was a reference distance. Despite flowing out of the processing solution for formation,
It has been found that bubbles exist in the measurement region even if the temperature, concentration, etc. of the processing liquid are different. In other words, the presence of bubbles in the measurement area can occur not only because the distance between the measurement window and the substrate surface is deviated from the reference distance, but also due to other factors such as the temperature and concentration of the processing liquid. found.

On the other hand, the inventor of the present invention adjusts the distance between the measurement window and the substrate surface as appropriate, irrespective of the cause of the presence of air bubbles, and determines the amount of the processing liquid for forming the liquid curtain. It has been found that by appropriately adjusting the value of, the generation of bubbles and the like can be suitably suppressed. Further, the present inventors have also found that the presence of bubbles in the measurement area causes a characteristic change in the amount of measurement light reflected from the substrate surface.

Based on the above research results, the present inventor:
The following invention which can automatically suppress the presence of bubbles in the measurement area has been made.

That is, among the inventions made by the present inventors,
The invention according to claim 1 has a measurement window facing the substrate surface, irradiates measurement light to the substrate surface through the measurement window, and from the substrate surface of the measurement light through the measurement window. Reflected light quantity measuring means for measuring the quantity of reflected light (reflected light quantity), and end point detecting means for analyzing a change in the reflected light quantity measured by the reflected light quantity measuring means and detecting the end time of the surface treatment on the substrate surface And a liquid curtain forming means for filling a measurement area between the measurement window and the substrate surface with a processing liquid to form a curtain of the liquid in the measurement area, and supplying the processing liquid to the substrate surface. In a surface treatment for removing a layer to be removed formed on the surface of the substrate, a surface treatment end point detection device for forming a curtain of the treatment liquid in the measurement area and detecting an end point of the surface treatment. , The measurement And a contacting / separating unit for bringing the substrate surface into and out of contact with the substrate surface, a processing condition capturing unit for capturing a processing condition including an interval between the measurement window and the substrate surface before the surface processing, and Control means for controlling the contact / separation means so that the distance between the measurement window and the surface of the substrate is set to an optimum distance.

According to a second aspect of the present invention, in the surface treatment end point detecting device according to the first aspect, a liquid outflow amount adjusting variably the liquid outflow amount of the processing liquid from the liquid curtain forming means. Means for controlling the distance between the measurement window and the substrate surface to an optimum distance, and further, the reflection amount measured by the reflected light amount measurement means by bubbles present in the measurement area. While examining a change in the amount of light appearing in the amount of light (hereinafter, referred to as a "change in the amount of air bubbles"), the outflow amount of the processing liquid from the liquid curtain forming means is controlled by controlling the liquid outflow amount adjusting means so as to eliminate the change in the amount of air bubbles Is adjusted by feedback control.

According to a third aspect of the present invention, there is provided a measurement window facing a substrate surface, irradiating the substrate surface with measurement light through the measurement window, and measuring the measurement light through the measurement window. A reflected light quantity measuring means for measuring the quantity of reflected light (reflected light quantity) from the substrate surface, and analyzing a change in the reflected light quantity measured by the reflected light quantity measuring means to determine the end point of the surface treatment on the substrate surface. End point detecting means for detecting, and a liquid curtain forming means for forming a curtain of the liquid in the measurement area by filling the processing area in the measurement area between the measurement window and the substrate surface, At the time of surface treatment for supplying the treatment liquid and removing a layer to be removed formed on the surface of the substrate, a surface for forming a curtain of the treatment liquid in the measurement area and detecting an end point of the surface treatment Processing end point detection device A light amount change (hereinafter, referred to as a “bubble light amount”) that is included in the reflected light amount measured by the reflected light amount measuring unit due to bubbles existing in the measurement area; Change)
And control means for controlling the contact / separation means so as to eliminate the change in the amount of air bubbles while adjusting the distance between the measurement window and the substrate surface by feedback control.

According to a fourth aspect of the present invention, there is provided the surface treatment end point detecting device according to the third aspect, wherein the outflow amount of the processing solution from the liquid curtain forming means is variably adjusted. Means for controlling the distance between the measurement window and the substrate surface by feedback control so as to eliminate the change in the amount of air bubbles while checking the change in the amount of air bubbles, and forming the liquid curtain. The amount of the processing liquid flowing out from the means is adjusted by feedback control.

According to a fifth aspect of the present invention, in the surface treatment end point detecting device according to any one of the third and fourth aspects, the distance between the measurement window and the substrate surface before the surface treatment is included. The apparatus further includes processing condition capturing means for capturing processing conditions, and the control means adjusts the distance between the measurement window and the substrate surface by feedback control,
And, prior to the adjustment by the feedback control of the outflow amount of the processing liquid from the liquid curtain forming means, the distance between the measurement window and the substrate surface is set to an optimum distance based on the fetched processing conditions. It is characterized in that the contact / separation means is controlled.

[0023]

The operation of the present invention is as follows. That is,
According to the first aspect of the present invention, the processing condition capturing means captures the processing conditions, and the control means contacts and separates the distance between the measurement window and the substrate surface based on the captured processing conditions so that the distance between the measurement window and the substrate surface is an optimum distance. Control means. Here, the optimal interval is an interval at which bubbles do not exist in the measurement area according to the processing conditions. For example, the presence of bubbles in the measurement area is purely the interval between the measurement window and the substrate surface. The above-mentioned optimum interval is the reference interval if the deviation is caused by deviation from the reference interval. In addition, if the optimal interval is also caused by the temperature or concentration of the processing solution, for example, the reference interval The distance is slightly shifted from the above. In addition, the processing conditions to be taken in include the distance between the measurement window and the substrate surface before the surface processing, and when other processing conditions such as the temperature and concentration of the processing solution can vary, the other processing conditions The distance between the measurement window and the substrate surface is adjusted to an optimum distance according to the processing conditions.

According to the second aspect of the present invention, after the control means sets the distance between the measurement window and the substrate surface to the optimum distance, the control means further measures the amount of reflected light by the bubbles present in the measurement area. While checking the change in the amount of air bubbles, the liquid outflow amount adjusting means is controlled so as to eliminate the change in the amount of air bubbles, and the amount of outflow of the processing liquid from the liquid curtain forming means is adjusted by feedback control. That is, even if the distance between the measurement window and the substrate surface is set to the optimum distance, bubbles may be present in the measurement area due to some other factor. Even in such a case, the reflected light amount measurement is performed by the bubbles. By performing feedback control on the basis of a change in the amount of air bubbles appearing in the amount of reflected light measured by the means so that the air bubbles actually disappear, the presence of air bubbles in the measurement area can be more reliably suppressed.

According to the third aspect of the present invention, the air bubbles are actually eliminated based on the change in the amount of air bubbles measured by the reflected light amount measuring means by the air bubbles existing in the measurement area.
The distance between the measurement window and the substrate surface is adjusted by feedback control. This makes it possible to automatically search for the optimum distance between the measurement window and the substrate surface where bubbles are actually eliminated irrespective of what requirement causes bubbles to be present in the measurement region.

According to the fourth aspect of the invention, the feedback control based on the change in the amount of bubbles is performed in addition to the adjustment of the distance between the measurement window and the substrate surface, and the flow of the processing liquid from the liquid curtain forming means. It is possible to adjust the amount.
Any of the adjustment by feedback control of the distance between the measurement window and the substrate surface and the adjustment by feedback control of the flow-out amount of the processing liquid from the liquid curtain forming means may be performed first or prioritized. .

According to the fifth aspect of the present invention, prior to the feedback control of the third and fourth aspects, similarly to the first aspect of the invention, the distance between the measurement window and the substrate surface is adjusted according to the processing conditions. Is controlled to set the optimal interval.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic overall configuration diagram of an etching apparatus, which is one of surface treatment apparatuses provided with a surface treatment end point detection device according to the present invention. FIG. 2 is a diagram illustrating a measurement head, first and second light source units, FIG. 3 is a diagram illustrating a detailed configuration of the liquid curtain control unit, and FIG. 3 is a diagram illustrating a schematic configuration of a lifting drive mechanism.
In the following embodiment, an end point detection in a case where a layer (removal layer) to be removed of a glass substrate for a liquid crystal display on which a predetermined surface layer including a layer (film) to be removed is formed is removed by etching will be described as an example. As will be described, the present invention is similarly applied to the detection of the end point when the removal layer of the semiconductor wafer on which the predetermined surface layer including the removal layer is formed is removed by etching and the detection of the end point of the development processing of these various substrates. can do.

In FIG. 1, reference numeral 1 denotes an etching tank, in which a transport roller group 2 for holding a substrate S in a horizontal position and reciprocating in a horizontal direction is provided. In the vicinity of both ends of the transport roller group 2, sensors 3a and 3b composed of micro switches and the like are provided. When one end of the substrate S conveyed rightward in FIG. 1 comes into contact with the sensor 3a on the right side, a detection signal is given to the control unit 4. As a result, the control unit 4 reverses the drive mechanism (not shown) of the transport roller group 2, and the substrate S is transported in the reverse direction. Then, when the other end of the substrate S contacts the left sensor 3b, the transport direction of the substrate S is switched. Hereinafter, the substrate S is reciprocated in the horizontal direction at a constant cycle by alternately contacting the left and right ends of the substrate S with the left and right sensors 3a and 3b.

Above the transport roller group 2, a nozzle 5 for ejecting an etching solution is provided. The etching liquid stored in the storage tank 6 is sent to the nozzle 5 by the pump 7, and while the nozzle 5 is oscillated by the motor 8,
The etching liquid is sprayed on the surface of the substrate S (the surface on which the removal layer is formed) that is reciprocated in the horizontal direction. The drive control of the pump 7 and the motor 8 is also performed by the control unit 4.

A measuring head 10 is provided above the substrate S. The measuring head 10 is optically connected to the first and second light source units 11 and 12 via optical fibers 13a and 13b, and connects an end point detecting unit 14, a liquid curtain control unit 15 and cables 16a and 16b. Are electrically connected via

The first light source section 11 mainly emits measurement light used for detecting the end point of the etching process. As shown in FIG. 2, the first light source section 11 includes a halogen lamp, a xenon lamp, and the like. 11a, filters 11b and 11c for wavelength selection, a condenser lens 11d, and the like. From the measurement light emitted from the light source 11a, only light of a predetermined wavelength or wavelength band is extracted by filters 11b and 11c as needed, collected by a condenser lens 11d, and guided to an entrance of an optical fiber 13a. Is guided to the measuring head 10 through the optical fiber 13a.

In the filter 11b, for example, 190
Filter out only the light in the wavelength band of
c selectively extracts a more optimal wavelength (for example, 430 nm or 460 nm) or a wavelength band (430 to 460 nm or the like) from the wavelength bands extracted by the filter 11b.
For example, the surface of a glass substrate S for a liquid crystal display is ITO
(Indium-Thin-Oxide: Indium Tin Oxide) film is formed, and then a resist film is formed in a predetermined pattern on the film, and the ITO film in the etching region where the resist film is not formed is removed by etching. When the light in the wavelength band of 190 to 500 nm is used as the measurement light, the S / N ratio of the measured light amount of the reflected light from the substrate S is improved due to the refractive index between the glass substrate S and the ITO film, etc. Furthermore, of the wavelength band of 190 to 500 nm, a wavelength (for example, 430 nm or 460 nm) or a wavelength band (43 nm) that reduces the reflectance in the mask region where the resist film is formed.
If 0 to 460 nm is used as the measurement light, the S / N ratio of the measurement light amount of the reflected light used for the end point detection is further improved. Extraction of these wavelengths or wavelength bands is performed by filters 11b and 11c as necessary.

The second light source unit 12 is for projecting measurement light used for measuring a distance W between the measurement window 17 of the measurement head 10 and the surface of the substrate S. The measuring light emitted from the light source 12a is condensed by the condensing lens 12b and guided to the entrance of the optical fiber 13b, and the optical fiber 13b The light is guided to the measurement head 10 through the light source.

Driving control for the first and second light source units 11 and 12 (control of turning on / off the light sources 11a and 12a, etc.) is performed by the control unit 4.

The measuring head 10 has an optical system (hereinafter referred to as a monitor optical system) 20 for mainly detecting the end point of the etching process, and an interval W between the measuring window 17 and the surface of the substrate S. Optical system (hereinafter referred to as interval detection optical system)
30 are provided. The monitor optical system 20 includes a slit 21, a collimator lens 22, a half mirror 23, a mirror 24, an imaging lens 25, a slit 26, and a light receiving element 2.
7, the interval detection optical system 30 includes a slit 31,
It comprises a collimator lens 32, a half mirror 33, an objective lens 34, an imaging lens 35, a light receiver 36, and an interval detector 37.

The measurement light from the first light source unit 11 is guided into the measurement head 10 through the optical fiber 13a, the light beam is narrowed down by the slit 21, the light is collimated by the collimator lens 22, and the half mirror 23 is The light passes through the measurement window 17 formed of a glass plate or the like, and is irradiated on the surface of the substrate S. This measurement light beam is reflected by the surface of the surface layer formed on the surface of the substrate S, the interface between the films constituting the surface layer, the lowermost layer of the surface layer and the interface between the surface of the substrate S, and the like. The interference light beam of the reflected light passes through the measurement window 17 again, the optical path is changed by the half mirror 23 and the mirror 24, and the light beam is condensed by the imaging lens 25, and the light beam is narrowed by the slit 26, and the light receiving element such as a photodiode is received. The light is received at 27 and its light quantity is measured. The amount of reflected light (interference light) from the surface of the substrate S measured by the light receiving element 27 is equal to a predetermined time t.
_At every ₁ (for example, 10 ms), it is taken into the end point detection unit 14 and the liquid curtain control unit 15 via the cable 16a.

The measuring light from the second light source unit 12 is guided into the measuring head 10 through the optical fiber 13b, the light beam is narrowed down by the slit 31, the parallel light beam is converted by the collimator lens 32, and the half mirror 33 is moved. Transmission, objective lens 34
Pass through a position deviated from the optical axis OA, and pass through the measurement window 17 to irradiate the surface of the substrate S. The reflected light of the measurement light from the surface of the substrate S passes through the measurement window 17 again, passes through a position deviated from the optical axis OA of the objective lens 34, and the optical path is changed by the half mirror 33 to form the imaging lens 35. And is received at a predetermined position (light receiving element) of a light receiving device 36 such as a photodiode array or a CCD in which a plurality of light receiving elements are arranged in a one-dimensional direction.

The distance W between the measurement window 17 and the surface of the substrate S (hereinafter, simply referred to as “space W” means the distance W between the measurement window 17 and the surface of the substrate S) is a predetermined reference. When the distance is Wx, the components 31 to 36 of the distance detecting optical system 30 are adjusted and arranged so that the reflected light of the measurement light from the surface of the substrate S is received at the central position (light receiving element) Px of the light receiver 36. ing. In this case, if the interval W is wider than the predetermined reference interval Wx (in the case where the position of the substrate S with respect to the measurement window 17 is lower than the position at the time of the reference interval Wx in the figure), FIG. As shown by the imaginary line, the center of gravity of the region where the reflected light of the measurement light from the surface of the substrate S is received by the light receiver 36 is shifted downward in FIG. On the other hand, when the interval W is narrower than the predetermined reference interval Wx (in the case where the position of the substrate S with respect to the measurement window 17 is shifted above the position at the time of the reference interval Wx),
Contrary to the case where the interval W is wider than the predetermined reference interval Wx, the center of gravity of the region where the reflected light of the measurement light from the surface of the substrate S is received by the light receiver 36 is shifted upward in FIG. Further, the amount of deviation of the interval W from the predetermined reference interval Wx corresponds to the amount of deviation of the center of gravity of the light receiving area of the light received by the light receiver 36 from the surface of the substrate S from Px. The interval detection unit 37 determines that the interval W is the reference position Wx based on the above principle.
Is detected, and the detection result is provided to the liquid curtain control unit 15 via the cable 16b.

The measuring head 10 is configured to be able to move up and down (so that the distance W can be widened and narrowed) with respect to the substrate S held by the transport roller group 2 in a horizontal posture. The lifting drive mechanism 40 for raising and lowering can be realized by various configurations, an example of which is shown in FIG. That is, an elevating guide 41 is attached to the measuring head 10, and the elongate hole 4 of the elevating guide 41 is
2 is slidably fitted to a cylindrical member 43 rotatably provided on the inner surface of the etching tank 1, and the measuring head 10 is held in the etching tank 1 (horizontal posture by the transport roller group 2). It can move up and down with respect to the substrate S). The lower end of the lifting guide 41 is received on the inclined surface of the member 44. A screw shaft 45 is attached to the base end of the member 44, and a worm gear (not shown) rotated by a stepping motor 46 is meshed with the screw shaft 45 in an orthogonal state. Then, the worm gear is rotated in the forward and reverse directions by the stepping motor 46, so that the screw shaft 4 is rotated.
5. The member 44 is displaced in the horizontal direction in the figure, and the elevating guide 41 is moved up and down along the inclined surface of the member 44,
0 is raised and lowered with respect to the substrate S. The moving amount of the elevation of the measuring head 10 is controlled by the number of driving steps of the stepping motor 46, and the driving control of the stepping motor 46 is performed by the liquid curtain control unit 15.

In the drawing, reference numeral 47 denotes a shielding wall which prevents driving components such as the stepping motor 46 from being exposed to the atmosphere of the etching solution scattered in the etching tank 1.

The lifting drive mechanism 40 may be constituted by a well-known uniaxial drive mechanism including a screw shaft, a guide shaft, a motor, and the like, in addition to the above-described structure.

Further, in the lifting / lowering drive mechanism 40 shown in FIG. 3 and the above-mentioned modified example, in order to prevent the drive parts such as the motor from being exposed to the etching solution atmosphere,
The driving parts may be designed to be provided outside the etching tank 1.

In this embodiment, a liquid curtain forming mechanism 50 is provided. As shown in FIG. 2, the liquid curtain forming mechanism 50 includes a liquid outlet 51, a liquid feed pipe 52, and a flow control valve 5.
3. The liquid supply unit 54 and the like. Liquid outlet 51
Is configured such that a wall surface 55 near the measurement window 17 of the measurement head 10 is an inner wall, and an outer wall 56 is provided therearound. The upper part of the space 57 between the inner wall 55 and the outer wall 56 is closed,
On the other hand, the lower part of the space 57 is open. Liquid supply pipe 5
One end of 2 is connected to the space 57, and the other end is connected to the liquid supply unit 54. The etching liquid supplied from the liquid supply unit 51 is supplied to the space 57 of the liquid outflow unit 51 via the liquid supply pipe 52, and flows out from the lower part of the space 57 toward the surface of the substrate S. Measurement window 17
In the measurement area 18 between the substrate and the surface of the substrate S, the etchant EQ
Is to be satisfied. The liquid curtain forming mechanism 50 of the present embodiment is configured such that the amount of liquid sent through the liquid sending pipe 52 can be arbitrarily adjusted by the flow control valve 53, and by this adjustment, the liquid outlet 51 ( (Below the space 57)
It is possible to arbitrarily change and adjust the amount of liquid flowing out of the apparatus. The flow control of the flow control valve 53 is performed by the liquid curtain control unit 15. The control of the formation of the liquid curtain itself, that is, the control of the supply of the processing liquid from the liquid supply unit 54 and the control of the stop thereof are performed by the control unit 4.

The end point detecting section 14 is constituted by a microcomputer, a personal computer, or the like, and analyzes a change in the amount of reflected light from the surface of the substrate S measured by the monitor optical system 20 in the measuring head 10. The end point of the etching is detected by a conventionally known method. That is, as described above, the reflected light from the surface of the substrate S
The interference light reflected from the surface of the surface layer formed on the surface of the substrate, the interface between the films constituting the surface layer, and the interface between the lowermost layer of the surface layer and the surface of the substrate S. In the process of removing the removal layer, the amount of reflected light changes in accordance with the decrease in the thickness of the removal layer. After the removal layer is removed, the film of each film constituting the surface bath is removed. Since the thickness does not change, the amount of reflected light does not change and becomes constant.
Therefore, a point in time when the amount of reflected light changes from a state in which it changes to a state in which it does not change is specified, and this point is defined as the end point of the etching process. When detecting the end point, the end point detection unit 14 supplies an end point detection signal to the control unit 4. The control unit 4 stops each unit based on the end point detection signal, and ends the etching process.

The liquid curtain control unit 15 is also constituted by a microcomputer or a personal computer,
A U (central processing unit) 61, a memory 62, a program memory 63, and the like are provided. The CPU 61 follows the program (processing procedure) created in advance and stored in the program memory 63, as will be described later.
And the flow rate adjustment of the stepping motor 46 of the lifting drive mechanism 40 and the liquid curtain forming mechanism 50 for raising and lowering the measuring head 10 based on the current interval W given by the monitor and the amount of reflected light measured by the monitor optical system 20. By appropriately controlling the drive of the valve 53, an interval W and a liquid outflow amount that can appropriately suppress bubbles in the processing liquid filled in the measurement area 18 are specified. The memory 62 also stores collected data for one cycle of the horizontal reciprocation of the substrate S (the amount of reflected light measured by the monitor optical system 20 during one cycle of the horizontal reciprocation of the substrate S). Are stored in areas M1, M2, and the like. The area M1 stores the current one cycle of collected data, and the area M2 stores the previous one cycle of collected data. The liquid curtain control unit 15 is also provided with detection information of the sensors 3a and 3b from the control unit 4.

The monitor optical system 2 in the measuring head 10
0 and the first light source unit 11 constitute a reflected light amount measuring unit in the present invention, the end point detecting unit 14 corresponds to the end point detecting unit in the present invention, and the liquid curtain forming mechanism 50 corresponds to the liquid curtain forming unit in the present invention. I do. The lifting drive mechanism 40 corresponds to the contact / separation unit in the present invention, and the interval detection optical system 30 and the second light source unit 12 in the measurement head 10 constitute the processing condition capturing unit in the present invention. further,
The liquid curtain control unit 15 corresponds to a control unit in the present invention, and the flow control valve 53 corresponds to a liquid outflow amount adjusting unit in the present invention.

The end point detection of the etching process by the apparatus having the above-described configuration is performed by the liquid curtain forming mechanism 5.
0 is performed in a state where the measurement region 18 is filled with an etching solution used in the etching process.

As described above, the interval W is equal to the reference interval W
In some cases, bubbles may be present in the measurement area 18 even if the processing conditions such as the temperature and concentration of the etching liquid (processing liquid) deviate from x or the processing conditions are different.

Therefore, the liquid curtain control unit 15 determines the distance W and the amount of the etchant flowing out of the liquid curtain forming mechanism 50 (hereinafter, referred to as “outflow”) so as to eliminate bubbles in the measurement area 18.
The “liquid outflow amount” is simply referred to as the liquid curtain forming mechanism 5.
It means the amount of the etchant flowing out from zero. ). This operation will be described with reference to the flowcharts shown in FIGS.

It is assumed that the initial value of the liquid outflow amount is set to a reference liquid outflow amount determined in the conventional apparatus. In addition, the flowcharts of FIGS.
The substrate S is set on the swing roller group 2 and the nozzle 5
Of the etching liquid from the liquid curtain forming mechanism 50
5 shows the operation from the state where the formation of the liquid curtain at the reference liquid outflow amount is started.

First, it is determined whether or not the current interval W (before surface treatment) is deviated from the reference interval Wx. If it is deviated, the process of step S2 is executed. If not, the process proceeds to step S3 ( Step S1). Whether the current interval W is deviated from the reference interval Wx is determined by the interval detection optical system 30.
It is determined from the detection result from.

In step S2, the interval W is set to the reference interval Wx
The measurement head 10 is driven up and down so that In addition, from the detection result from the interval detecting optical system 30, it is possible to determine whether the current interval W is shifted widely or narrowly than the reference interval Wx, and the shift amount. The driving of the stepping motor 46 of the elevation drive mechanism 40 is controlled based on the driving direction and the moving amount.

In this flowchart, the optimum interval is fixed to the reference interval Wx. For example, the measurement area 1 is only due to the fact that the interval W is deviated from the reference interval Wx due to mechanical deterioration such as wear of the swing roller group 2 or the like.
If bubbles are present in the sample 8, if the interval W is set to the reference interval Wx, the amount of liquid flowing out is the reference amount of liquid flowing out. is expected. Actually, the interval W is equal to the reference interval W
measurement area 1 due to factors other than deviation from x
Since it is possible that bubbles are present in the nozzle 8, such a case is dealt with, and in this flowchart, as described below, measurement is performed by adjusting the interval W and the liquid outflow amount by feedback control. The bubbles in the area 18 are eliminated.

[0055] In step 3, the incorporation amount of one period of the reflected light of the reciprocating movement in the horizontal direction of the substrate S (the amount of reflected light) in a predetermined time interval t _1, the digital data by the A / D converter (not shown) converts Then, the data is stored in the storage area M1 of the collected data for the current one cycle in the memory 62.

During one cycle of the horizontal reciprocation of the substrate S, the spot SP of the measurement light emitted from the monitor optical system 20 to the surface of the substrate S is displaced as shown by the imaginary line in FIG. Incorporation into the liquid curtain controller 15 of the reflected light amount is made at a predetermined time t ₁ interval. The liquid curtain control unit 15
After receiving a signal that the substrate S has contacted the right (or left) sensor 3a (or 3b) via the control unit 4,
The same sensor 3a (or 3b) to store the amount of reflected light from the monitor optical system 20 to sequentially storage area M1 is taken at a predetermined time t ₁ interval until it receives a signal substrate S is contacted again via the control unit 4 Thus, the amount of reflected light for one cycle of the horizontal reciprocation of the substrate S is collected.

FIGS. 9A and 9B show the collected reflected light amounts for one cycle. In the figure, the vertical axis represents the amount of reflected light, and the horizontal axis represents time. FIG. 9A is a graph in a case where no air bubble exists in the measurement region 18, and FIG. 9B is a graph in a case where an air bubble exists in the measurement region 18.

As shown in FIG. 9A, since a pattern for etching is formed on the surface of the substrate S, a region to be etched by a region measured by the monitor optical system 20 (etched region). And a non-etched region (mask region), and the reflectance of the surface of the substrate S is different between the etched region and the mask region. As shown in FIG. 8, the spot SP of the measurement light emitted from the monitor optical system 20 to the surface of the substrate S moves along the same trajectory.
The change in the amount of reflected light in the graph shown in FIG.
Is the basis for the change in the amount of reflected light. The base of this change in the amount of reflected light hardly changes with the collected data for one cycle collected by one cycle of the reciprocating movement of the substrate S before and after.

As shown in FIG. 9B, if air bubbles are present in the measurement area 18, the air bubbles are displayed at an arbitrary position in the graph of FIG. So-called spike-like light quantity change (bubble light quantity change) in which the reflected light quantity changes sharply in a very short time due to scattered light due to
SS appears.

Returning to the flowchart of FIG. 4, it is determined whether or not the current collection in step S3 is for the first cycle. If the current cycle is for the first cycle, the process of step S5 is executed, and the process returns to step S3. If it is after the cycle, the process proceeds to step S6 (step S4).

If the current collection is the first cycle, step S
At 5, the storage data in the area M1 is transferred to the area M2 (storage area for the previously collected data) to prepare for the next second cycle of collection. Then, in the same manner as described above, the collection in the second cycle (this time) is performed in step S3, and the process proceeds to step S6 according to the determination in step S4. At this time, the collected data of one cycle of the second cycle collected this time is stored in M1 which is the storage area of the current collected data, and the data collected last time is stored in M2 which is the storage area of the previously collected data. 1 of the first cycle
The collected data for the cycle is stored.

In step S6, the difference between the data stored in the area M1 and the data stored in the area M2 is obtained.
The number of bubble light quantity changes SS appearing in the collected data for the cycle is obtained. FIG. 9B shows the collected data of the previous cycle (for example, the first cycle), and FIG. 9C shows the collected data of the current cycle (for example, the second cycle). In this step S6, FIG.
The graph of FIG. 9B (the amount of reflected light of each graph measured at each t ₁ ) is subtracted from the graph of FIG. The result is shown in FIG.
(D).

As is apparent from the figure, as a result of the difference between the current collected data and the previous collected data, the base of the change in the amount of reflected light in each graph is canceled. On the other hand, since the places where the bubble light amount changes SS appear in each graph are random, the places where the respective bubble light amount changes SS appear in the current data collection and the previous data collection do not match. Therefore, FIG.
As shown in (d), in the result of the difference, the bubble light amount change SS that appeared during the current data collection and the bubble light amount change SS that appeared during the previous data collection remain. The change in bubble light amount SS (SSn) is (+)
On the side, the change in the amount of bubble light SS that appeared during the previous data collection
(SSp) remains on the (-) side.

Then, based on the results shown in FIG. 9D, the amount of change in the amount of air bubbles SS collected during the current data collection is searched, and the number thereof is obtained. For example, in FIG. 9D, the difference between the reflected light amounts of the adjacent measurement points is obtained for each measurement point at t _{1 in} order from the left side of the figure, and the difference value is
From around "0", it starts to increase, then from increase to decrease,
From the decrease, the location where the value changes to around “0” is searched, and such a location is referred to as the change in the amount of bubble light SS which appeared during the current data collection.
And find the number.

Next, it is determined whether or not there is a bubble light amount change SS (SSn) that has appeared during the current data collection.
If there is no S (SSn), the process proceeds to step S8. On the other hand, if there is a bubble light amount change SS (SSn), step S9 in FIG.
Go to (Step S7).

In step S8, the liquid curtain control unit 15
Is notified to the end point detection unit 14, and the current interval W and the liquid outflow amount are held. The end point detection unit 14 performs a normal end point detection process based on the notification from the liquid curtain control unit 15. At this time, the condition of the interval W and the liquid outflow amount adjusted so that no bubbles exist in the measurement area 18 is set. Since the end point is detected under the liquid curtain formed by the above, measurement errors due to bubbles and the like can be eliminated, and accurate end point detection can be performed.

When the interval W before the surface treatment is the reference interval Wx in step S1 or when the interval W is set to the reference interval Wx in the processing in step S2, the bubbles actually exist in the measurement area 18. The adjustment process by the liquid curtain control unit 15 can be completed after confirming that there is no such error in the collected data in the first cycle and the second cycle.

In step S9 (see FIG. 5), the number (current value) of changes in the amount of bubble light SS that has appeared during the current data collection.
Is compared with the number (previous value) of the bubble light quantity change SS that appeared in the previous data collection, which was obtained in the same manner as the previous time. If the current value has increased or is the same as the previous value, step S
Proceed to step S10, while if it has decreased, step S11
Proceed to. Here, for example, i (i is a natural number of 2 or more)
The number of the change in the amount of bubble light SS determined in step S6 based on the collected data in the cycle and the collected data in the (i-1) cycle is set as the previous value, and the collected data in the (i + 1) cycle and the collected data in the i cycle Then, the number of the bubble light amount change SS obtained in step S6 is used as the current value and the comparison is performed.
If the bubble light quantity change SS obtained from the collected data in the first cycle and the collected data in the second cycle is the current value, there is no previous value corresponding thereto, and in this case, “0” is set as the previous value. .

In steps S10 and S11, the measuring head 10 is moved toward and away from the surface of the substrate S by a predetermined movement amount. In step S10, the head is driven in a direction opposite to the previous driving direction. In step S11, driving is performed in the same direction as the previous driving direction, contrary to step S10. When step S10 or S11 is executed for the first time, the first driving direction is determined by using the predetermined driving direction as the previous driving direction, and when step S10 or S11 is executed, the executed driving direction is stored. When the step S10 or S11 is executed next, the stored driving direction is determined as the previous driving direction and the current driving direction is determined. Step S10,
The predetermined moving amount of the measuring head 10 in S11 is:
By setting the amount of movement corresponding to one drive pulse of the stepping motor 46 of the elevating drive mechanism 40 to be sufficiently small, it is possible to finely adjust the distance W by approaching and separating.

Next, the interval W in steps S10 and S11
Then, it is checked whether or not the adjustment exceeds the allowable range of the interval W (step S12). That is, if the measurement window 17 is too close to the surface of the substrate S, the substrate S may collide with the measurement head 10, and it is not possible to reduce the number of bubbles. Even if the distance is too far, reduction of bubbles cannot be expected. Therefore, the allowable range of the interval W is determined in advance, and if the allowable range is exceeded, it is difficult to eliminate bubbles by the contact / separation drive (adjustment of the interval W) between the measurement window 17 and the surface of the substrate W.
As will be described later, an adjustment process including adjustment of a liquid outflow amount is performed. The current interval W can be known from the detection result of the interval detection optical system 30.

In step S12, if the current interval W does not exceed the allowable range, step S13 is executed, and
On the other hand, if it exceeds the allowable range, step S14 in FIG. 6 is executed.

In step S13, as in step S5, the stored data in area M1 is transferred to area M2 to prepare for data collection in the next cycle. Then, returning to step S3 in FIG. 4, the interval W is adjusted while checking whether there is an actual bubble in the measurement area 18 based on the presence or absence of the bubble light amount change SS, and the bubble disappears in the measurement area 18 by this adjustment. If
Proceeding from step S7 to S8, the adjustment processing by the liquid curtain control unit 15 is terminated.

Next, the processing after step S14 will be described with reference to FIG.
This will be described with reference to the flowchart of FIG.

First, similarly to step S2, the elevation drive mechanism 40 is driven so that the interval W becomes the reference interval Wx (step S14). This is because when the process proceeds from step S12 to step S14, the current interval W exceeds the allowable range.
This is to return to x. Since the interval W at this time is known from the detection result of the interval detection optical system 30, the driving direction and the amount of movement for setting the current interval W to the reference interval Wx are determined.

Next, as in step S3, data for one cycle of the reciprocating movement of the substrate S in the horizontal direction is collected.
It is stored in the storage area M1 (step S15). Then, it is determined whether this is the first data collection or the second or later data collection since the processing after step S14 is executed (step S16). If it is the first data collection, the area is determined in the same manner as steps S5 and S13. The storage data of M1 is transferred to the area M2, and the process returns to step S15 in preparation for the next and subsequent data collection (step S17).
If the data is collected after the first time, the process proceeds to step S18.
When the last collected data of one cycle (stored in the area M1) is used in the processing up to step S13, the storage data of the area M1 is transferred to the area M2 before or after the processing of step S14. If it is changed to, steps S16 and S17 can be omitted.

In step S18, as in step S6, the difference between the stored data in the areas M1 and M2 is obtained, and the number of changes in the amount of bubble light SS appearing in the current collected data is obtained based on the difference.

Then, similarly to step S7, the presence / absence of bubbles in the measurement area 18 is determined based on the presence / absence of the bubble light quantity change SS obtained in step S18 (step S19). If not, the process proceeds to step S8 in FIG. 4 to end the adjustment process by the liquid curtain control unit 15. On the other hand, if there is a bubble light amount change SS in the measurement area 18, the current value and the previous value of the bubble light amount change SS are compared, as in step S9, and whether the current value is greater than the previous value or not. If the current value is smaller than the previous value, the process proceeds to step S22 (step S22).
20). As the previous value when this step S20 is first executed, the number of the last bubble light amount change SS obtained in the processing up to step S13 in FIGS. 4 and 5 may be used, or simply “0” may be used. May be used.

In steps S10 and S11 in FIG. 5, the measuring head 10 is moved toward and away from the surface of the substrate S by a predetermined moving amount.
In step 22, the amount of the etchant flowing out of the liquid curtain forming mechanism 50 is changed and adjusted by a predetermined adjustment amount. Further, in step S21, the change is adjusted in the direction opposite to the previous adjustment direction (increase or decrease), and in step S22, the change is adjusted in the same direction as the previous adjustment direction. When step S21 or S22 is executed for the first time, the first adjustment direction is determined using the predetermined adjustment direction as the previous adjustment direction, and when step S21 or S22 is executed, the executed adjustment direction is stored. In advance, when step S21 or S22 is executed next, the stored adjustment direction is determined as the previous adjustment direction and the current adjustment direction is determined. Step S2
1. The adjustment of the change of the liquid outflow amount in S22 is performed by adjusting the flow control valve 53 of the liquid curtain forming mechanism 50, and by setting the adjustment amount sufficiently small, the adjustment of the liquid outflow amount can be finely performed. Become so.

Next, proceeding to the flowchart of FIG. 7, it is checked whether or not the current outflow amount exceeds the permissible range of the outflow amount as a result of the adjustment of the outflow amount in steps S21 and S22 (step). S23). If the amount of liquid flowing out is too large or too small, the reduction of bubbles cannot be expected. In the liquid curtain formed by the liquid curtain forming mechanism 50, the liquid curtain is not formed on the entire surface of the substrate S in the area where the spot SP of the measurement light beam moves in FIG. Therefore, if the amount of the liquid flowing out of the processing liquid for forming the liquid curtain is too large, a large amount of the etching liquid is supplied to a part of the surface of the substrate S, and the etching process is performed only on a part of the surface of the substrate S. As a result, the etching process cannot be performed uniformly over the entire surface of the substrate S. Therefore, the allowable range of the liquid outflow amount is determined in advance, and the liquid outflow amount is adjusted within the allowable range.

In step S23, if the current liquid outflow amount does not exceed the allowable range, step S24 is executed, while if it exceeds the allowable range, step S25 is executed.

In step S24, steps S5 and S1
3, as in S17, the storage data in the area M1 is transferred to the area M2, and the data is collected in preparation for the next cycle of data collection.
The process returns to step S15.

In step S25, it is determined whether or not the result of the check in step S23 is that the current liquid outflow exceeds the upper limit or the lower limit of the allowable range of the liquid outflow. If the number exceeds the lower limit, the processing in step S26 is executed. If the number exceeds the lower limit, the processing in step S27 is executed.

In step S26, the measuring head 10 is brought closer to the surface of the substrate S by a predetermined moving amount.
In step S27, the measuring head 10 is moved away from the surface of the substrate S by a predetermined moving amount. This is performed by driving the stepping motor 46 of the lifting / lowering drive mechanism 40 in the same manner as in steps S10 and S11 in FIG. 5, and the amount of movement here is set to the same amount as the amount of movement in steps S10 and S11. Is done.

Then, as a result of the movement of the measuring head 10 with respect to the surface of the substrate S (adjustment of the interval W) in steps S26 and S27, the current interval W is within the allowable range (step S12).
(Same as the allowable range) is checked, and if it is outside the allowable range, the process proceeds to step S29, while if not, the process proceeds to step S30 (step S28).

In step S29, it is determined that adjustment for eliminating bubbles in the measurement area 18 is impossible, and an abnormal end is reported to the operator by turning on an abnormal lamp or sounding an abnormal buzzer, and the abnormal end is made. This is also notified to the control unit 4. When receiving the abnormality notification, the control unit 4 stops the operation of each unit and ends the etching process.

In step S30, the liquid outflow amount is returned to the reference liquid outflow amount, and the flow advances to step S24 to transfer the storage data in the area M1 to the area M2 as in steps S5, S13, and S17. The process returns to step S15 after preparing for data collection in the cycle of. Then, while checking whether there are actually bubbles in the measurement area 18 based on the presence or absence of the bubble light amount change SS, adjustment by feedback control of the liquid outflow amount and feedback control of the interval W are performed. If there are no bubbles in 18,
Proceeding from step S19 to S8, the liquid curtain control unit 15
Is terminated.

As a result, the distance W between the surface of the substrate S set on the oscillating roller group 2 and the measurement window 17 is reduced to the reference distance Wx due to mechanical deterioration such as wear of the oscillating roller group 2.
It can be corrected automatically even if it deviates from the temperature.
Even if bubbles are present in the measurement area 18 due to other processing conditions, the bubbles are properly corrected by adjusting the amount of outflow liquid by feedback control and adjusting the interval W by feedback control.

In the above-described operation, the adjustment processing by the liquid curtain control unit 15 is performed in parallel with the etching processing. However, for example, every time a predetermined number of substrates S are etched, the test substrate is changed. Only the adjustment process by the liquid curtain control unit 15 is executed using
The distance W and the liquid outflow amount are adjusted so that air bubbles do not exist in the measurement area 18, and the state is maintained and the subsequent substrate S
The etching process (for a predetermined number) may be executed.

As the test substrate, the substrate S to be etched may be used as a test substrate. For example, a glass substrate having the same thickness as the substrate S to be etched and having no surface layer formed thereon may be used. A substrate may be used. The distance between the surface of the test substrate on which the surface layer is not formed and the measurement window 17 is smaller than the distance between the substrate S to be etched (having the surface layer) and the measurement window 17 by the thickness of the surface layer. Although it is wide, the thickness of the surface layer is on the order of μm, and such a difference is absorbed in the range of the error, so that a sufficiently accurate adjustment can be performed even when a test substrate having no surface layer is used.

When the adjustment process shown in FIGS. 4 to 7 is performed on a test substrate on which a surface layer is not formed, since there is no division such as an etching region or a mask region, one cycle collected in step 3 or S15 Figure 1 shows the collected data
As shown in FIG. 10A, the base of the change in the amount of reflected light is constant. However, as shown in FIGS. Since the base of the change in the amount of reflected light of the data is canceled, the number of changes in the amount of bubble light SS due to the bubbles in the measurement area 18 can be obtained. Note that FIGS. 10A to 10D correspond to FIGS.
FIGS. 10A to 10D are diagrams corresponding to FIGS. 10A and 10D, and FIG. 10A is a graph showing collected data for one cycle when there is no bubble in the measurement area 18, and FIGS. Is the measurement area 18
FIG. 10D is a graph showing collected data for one cycle before and after when air bubbles are present, and FIGS.
It is a graph which shows the result of having subtracted (b).

Further, according to the above embodiment, even when the substrates S having different thicknesses are successively subjected to the etching process, the distance W or the distance between the substrates S having the respective thicknesses is reduced so that no bubbles are present in the measurement region 18. It is also possible to automatically adjust the liquid outflow. In the case where the substrates S having different thicknesses are successively etched, usually, the etching is performed for each lot of a plurality of substrates S of the same type (same thickness) as one unit. That is, for example, after a plurality of substrates S having a thickness of 7 mm are etched, then a plurality of substrates S having a thickness of 11 mm are etched, and a plurality of substrates S having the same thickness are continuously formed. Etching is performed. Therefore,
Prior to the etching process on the substrates S of each lot, only the adjustment process by the liquid curtain control unit 15 is performed using a test substrate, whereby the interval W and the amount of the liquid flowing out are set so that no bubbles are present in the measurement area 18. After the adjustment, the state may be maintained and the etching process may be performed on the substrates S (for a plurality of substrates) of the lot. In addition,
As the test substrate, a substrate having the same thickness as the substrate S of the lot and having no surface layer formed thereon may be used, or the same substrate as the substrate S to be etched in the lot (the surface layer is also formed). May be used. Further, the adjustment process by the liquid curtain control unit 15 may be executed in parallel with the etching process for each substrate W to be etched without using a test substrate.

Next, some modified examples of the adjustment processing by the liquid curtain control unit 15 described with reference to FIGS. 4 to 7 will be introduced.

In FIGS. 4 to 7, the processing conditions to be taken are only the interval W before the surface treatment, the optimal interval is the reference interval Wx, and the interval W is the reference interval Wx in steps S2 and S14. For example, by taking in other processing conditions such as the temperature and concentration of the etching solution, the optimum intervals for these various processing conditions are obtained in advance, and in steps S2 and S14, the interval W is set to such an optimum interval. You may make it.

In this case, as shown by a dotted line in FIG. 1, for example, a setting section 70 for the operator to set processing conditions such as the temperature and concentration of the etching solution during the etching process (this setting section 70 is also a processing condition). The liquid curtain control unit 15 is configured so that the processing condition set by the setting unit 70 is fetched. Further, for example, when the temperature of the etching solution is T ₁ and the concentration of the etching solution is N ₁ , the optimum interval is W.
_{11. When} the temperature of the etching solution is T ₁ and the concentration of the etching solution is N ₂ , the optimum interval is W ₁₂ , and the temperature of the etching solution is T ₂
For example, when the concentration of the etchant is N ₂ , the optimum interval is W _{22, and} the optimum interval such that no bubbles exist in the measurement region 18 is experimentally obtained in advance for various combinations of processing conditions. The results are stored in a table. Then, in steps S2 and S14, the liquid curtain control unit 15 retrieves the table using the fetched processing conditions as a search key, extracts an optimum interval corresponding to the fetched processing conditions, and sets the interval W to the optimum interval. The lifting drive mechanism 40 is controlled as described above.

In the flowcharts of FIGS. 4 and 5,
First, the interval W between the measurement window 17 and the substrate S is set to the reference interval Wx (steps S1 and S2), but the processing is omitted and the interval W is adjusted by the feedback control from steps S3 to S13. The bubbles in the measurement area 18 may be eliminated.

Similarly, in the processing of steps S14 to S30 in the flowcharts of FIGS. 6 and 7, step S14 is omitted, and the adjustment of the liquid outflow amount by the feedback control of steps S15 to S30 and the interval W of the feedback control are performed. The bubbles in the measurement area 18 may be eliminated by the adjustment.

For example, in the flowcharts of FIGS. 4 and 5, first, the interval W is set to a reference interval Wx (an optimal interval may be set according to the processing conditions), and then the measurement is performed by adjusting the interval W by feedback control. The gap W is found so that the bubbles in the area 18 disappear or the number of bubbles in the measurement area 18 is minimized. When the bubbles in the measurement area 18 disappear, the adjustment processing by the liquid curtain control unit 15 ends. (Process of step S8) On the other hand, the measurement area 18
If an interval W at which the number of bubbles in the space is minimized is found, the bubbles in the measurement area 18 may be eliminated by adjusting the liquid outflow amount by feedback control at the interval W.

In addition, air bubbles in the measurement area 18 are eliminated by independently executing the adjustment processing for setting the interval W to the reference interval Wx (which may be an optimum interval according to processing conditions) and the adjustment processing for the interval W by feedback control. You may do so.

[0099]

As is apparent from the above description, according to the first aspect of the present invention, a predetermined processing condition,
The distance between the measurement window and the substrate surface is automatically adjusted to the optimum distance based on the acquired processing conditions, so that the burden and labor on the operator can be reduced, and the operator (human body) can be saved. Danger from organic solvents and acids can also be avoided.

Further, even when the distance between the measurement window and the substrate surface is deviated from the reference distance due to, for example, deterioration of the machine, the distance between the measurement window and the substrate surface before the surface treatment is included before starting the surface treatment. By taking in the processing conditions, the distance between the measurement window and the substrate surface can be automatically adjusted to an optimum distance (for example, a reference distance) based on the processing conditions, and the substrates having different thicknesses can be continuously surfaced. Even when the substrate is put into the processing apparatus, the processing conditions including the distance between the measurement window and the substrate surface before the surface treatment are taken in for each substrate, and the distance between the measurement window and the substrate surface is determined based on this processing condition. It can be automatically adjusted to an optimal interval (eg, a reference interval).

Furthermore, taking into account other processing conditions such as the temperature and concentration of the processing liquid other than the distance between the measurement window and the substrate surface before the surface treatment, the distance between the measurement window and the substrate surface is adjusted to the optimum distance according to the other conditions. It can also be adjusted automatically.

According to the second aspect of the present invention, after the distance between the measurement window and the substrate surface is set to the optimum distance, the processing from the liquid curtain forming means is performed while checking for the presence or absence of actual bubbles in the measurement area. Since the outflow amount of the liquid is adjusted by the feedback control, the presence of bubbles in the measurement area can be more reliably suppressed.

According to the third aspect of the present invention, the distance between the measurement window and the substrate surface is adjusted by feedback control while checking for the presence or absence of actual bubbles in the measurement area. It is possible to automatically find the optimum distance between the measurement window and the substrate surface where bubbles actually disappear regardless of the presence of bubbles in the region.

According to the fourth aspect of the present invention, in addition to the third aspect of the present invention, the amount of the processing liquid flowing out from the liquid curtain forming means is adjusted by feedback control. Air bubbles in the region can be more appropriately and reliably eliminated.

According to the fifth aspect of the present invention, the distance between the measurement window and the substrate surface is first set to an optimum distance, and then the measurement window and the substrate are checked while checking for the presence or absence of actual bubbles in the measurement area. Adjustment of the distance from the surface by feedback control and adjustment of the amount of processing solution flowing out from the liquid curtain forming means by feedback control can be performed, reducing the processing time as compared with adjustment using only feedback control. can do.

[Brief description of the drawings]

FIG. 1 is a schematic overall configuration diagram of an etching apparatus which is one of surface treatment apparatuses provided with a surface treatment end point detection apparatus according to the present invention.

FIG. 2 is a diagram showing a detailed configuration of a measurement head, first and second light source units, and a liquid curtain control unit.

FIG. 3 is a diagram showing a schematic configuration of a lifting drive mechanism.

FIG. 4 is a flowchart illustrating an adjustment process performed by a liquid curtain control unit.

FIG. 5 is a flowchart showing an adjustment process by the liquid curtain control unit.

FIG. 6 is a flowchart showing an adjustment process by the liquid curtain control unit.

FIG. 7 is a flowchart showing an adjustment process by the liquid curtain control unit.

FIG. 8 is a plan view showing a locus of displacement of a spot of a measurement light beam during an etching process.

FIG. 9 is a diagram for explaining a method of calculating the number of changes in the amount of bubble light from collected data for one cycle of a horizontal reciprocal movement of a substrate on which a surface layer is formed.

FIG. 10 is a diagram for explaining a method of calculating the number of changes in the amount of bubble light from collected data for one cycle of a horizontal reciprocation of a test substrate on which a surface layer is not formed.

[Explanation of symbols]

 Reference Signs List 10 measuring head 11 first light source unit 12 second light source unit 14 end point detecting unit 15 liquid curtain control unit 17 measuring window 18 measuring region 20 monitor optical system 30 interval detecting optical system 40 Elevating drive mechanism 50 Liquid curtain forming mechanism 53 Flow rate control valve S Substrate SS Bubble light quantity change

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ identification code FI H01L 21/66 H01L 21/306 E (58) Field surveyed (Int.Cl. ⁷ , DB name) G01B 11/00 H01L 21 / 306

Claims (5)

(57) [Claims] A measurement window facing the substrate surface, irradiating measurement light to the substrate surface through the measurement window, and measuring a reflected light of the measurement light from the substrate surface through the measurement window. Reflected light quantity measuring means for measuring the light quantity (reflected light quantity); end point detecting means for analyzing a change in the reflected light quantity measured by the reflected light quantity measuring means to detect the end time of the surface treatment on the substrate surface; Liquid curtain forming means for filling the measurement area between the window and the substrate surface with the processing liquid to form a curtain of the liquid in the measurement area, and supplying the processing liquid to the substrate surface to supply the processing liquid to the substrate. In a surface treatment end point detection device for forming a curtain of the treatment liquid in the measurement area and detecting an end point of the surface treatment during a surface treatment for removing a layer to be removed formed on the surface, the measurement window And said Contacting / separating means for bringing the substrate surface into and out of contact; processing condition capturing means for capturing processing conditions including an interval between the measurement window and the substrate surface before the surface processing; and measuring based on the captured processing conditions. Control means for controlling the contact / separation means so that the distance between the window and the surface of the substrate is set to an optimum distance. 2. The surface treatment end point detecting device according to claim 1, further comprising a liquid outflow amount adjusting means for variably adjusting a liquid outflow amount of the processing liquid from the liquid curtain forming means, and the control means. After the distance between the measurement window and the substrate surface is set to an optimum distance, the light amount change (hereinafter, “bubble”) that appears in the reflected light amount measured by the reflected light amount measuring unit due to bubbles existing in the measurement area. Change in light intensity)
Surface treatment end point detection, characterized in that the liquid outflow amount of the processing liquid from the liquid curtain forming means is adjusted by feedback control by controlling the liquid outflow amount adjusting means so as to eliminate the change in the bubble light amount while checking apparatus. 3. A measurement window facing the substrate surface, irradiating the substrate surface with measurement light through the measurement window, and measuring light reflected from the substrate surface through the measurement window. Reflected light quantity measuring means for measuring the light quantity (reflected light quantity); end point detecting means for analyzing a change in the reflected light quantity measured by the reflected light quantity measuring means to detect the end time of the surface treatment on the substrate surface; Liquid curtain forming means for filling the measurement area between the window and the substrate surface with the processing liquid to form a curtain of the liquid in the measurement area, and supplying the processing liquid to the substrate surface to supply the processing liquid to the substrate. In a surface treatment end point detection device for forming a curtain of the treatment liquid in the measurement area and detecting an end point of the surface treatment during a surface treatment for removing a layer to be removed formed on the surface, the measurement window And said And moving means for contacting and separating the sheet surface, the amount of light changes appearing in the reflected light amount measured by the reflected light amount measuring means by bubbles present in the measuring region (hereinafter,
Control means for controlling the contact / separation means so as to eliminate the change in the amount of air bubbles while checking the change in the amount of air bubbles, and adjusting the distance between the measurement window and the substrate surface by feedback control. A surface treatment end point detecting device, characterized in that: 4. The surface treatment end point detecting device according to claim 3, further comprising a liquid outflow amount adjusting means for variably adjusting a liquid outflow amount of the processing liquid from the liquid curtain forming means, and the control means. While examining the change in the light amount of the bubbles, the distance between the measurement window and the substrate surface is adjusted by feedback control so as to eliminate the change in the light amount of the bubbles, and the amount of the outflow of the processing liquid from the liquid curtain forming means is adjusted. A surface treatment end point detection device, wherein the adjustment is performed by feedback control. 5. The surface treatment end point detecting device according to claim 3, further comprising a processing condition capturing unit configured to capture processing conditions including an interval between the measurement window and the substrate surface before the surface processing. And the control means adjusts the distance between the measurement window and the substrate surface by feedback control, and prior to the adjustment by feedback control of the amount of the processing liquid flowing out of the liquid curtain forming means, A surface treatment end point detecting device, wherein the contact / separation means is controlled so that an interval between the measurement window and the substrate surface is set to an optimum interval based on the taken-in processing conditions.