JP5066887B2 - Water quality evaluation method and apparatus - Google Patents

Description

  The present invention relates to an apparatus for evaluating water quality, such as ultrapure water, and a water quality evaluation method using the apparatus, and in particular, the test water is brought into contact with the electronic device substrate and the surface property of the electronic device substrate is measured. The present invention relates to a water quality evaluation apparatus and a water quality evaluation method for evaluating water quality.

  A large amount of ultrapure water is used in the manufacturing process of electronic devices such as semiconductors and liquid crystals. Since the impurity concentration in the ultrapure water affects the electronic device substrate, it is necessary to detect the impurity in the ultrapure water.

  As a water quality evaluation method for detecting the impurity concentration in ultrapure water, Japanese Patent Application Laid-Open No. 2001-208748, Japanese Patent Application Laid-Open No. 2001-228138, and Japanese Patent Application Laid-Open No. 2001-237289 disclose that a semiconductor substrate (wafer) is accommodated in a container and ultrapure water is used. Is passed through the container to allow impurities in the ultrapure water to adhere to the wafer, and then the surface properties of the semiconductor substrate are measured to evaluate the quality of the ultrapure water.

  Of the above, Japanese Patent Application Laid-Open No. 2001-208748 takes out the wafer from the container after drying, dries it, measures the number of fine particles on the wafer surface with a wafer particle counter, and evaluates the water quality. Japanese Patent Laid-Open No. 2001-228138 similarly evaluates the water quality by measuring the iron concentration on the wafer surface taken out from the container and dried with a total reflection X-ray fluorescence spectrometer.

  In these methods, since the wafer is taken out of the container, measurement errors due to wafer contamination may increase. In addition, the total reflection X-ray fluorescence analyzer is large and expensive.

In Japanese Patent Laid-Open No. 2001-237289, a wafer is rotated at high speed in a container and dried, and then measured with a total reflection X-ray fluorescence analyzer. Error due to wafer contamination is eliminated, but total reflection fluorescence is eliminated. X-ray analyzers are large and expensive. Further, a mechanism for rotating the container at a high speed is required, and the container cost is high.
JP 2001-208748 A JP 2001-228138 A JP 2001-237289 A

  An object of the present invention is to solve the above-mentioned conventional problems and to provide a water quality evaluation apparatus and method capable of accurately evaluating the quality of water such as ultrapure water while having a relatively simple apparatus configuration.

The water quality evaluation apparatus according to claim 1 has a storage chamber for storing an electronic device substrate, a container having an inlet and an outlet for circulating test water in the storage chamber, and an electron stored in the storage chamber. a light irradiating means for irradiating light to the device substrate, and receives the reflected light or scattered light from the electronic device substrate Ri name and a light receiving means for detecting the intensity of light of the light emitting means The irradiation end and the light receiving end of the light receiving means are respectively exposed in the storage chamber, and the container has a bottom plate having the storage chamber and an upper lid for closing the storage chamber, The storage chamber is formed of a circular recess recessed from the upper surface of the bottom plate, and the inflow port for allowing the test water to flow into the storage chamber is provided at the center of the upper lid, and at the center of the bottom surface of the storage chamber, The outlet for allowing the test water to flow out of the storage chamber is provided. The light irradiation means includes an irradiation light source disposed outside the container, and an irradiation light introducing member for guiding the light irradiated from the irradiation light source into the storage chamber. The introduction member is inserted from the upper surface of the upper lid toward the center of the upper surface of the substrate in the accommodation chamber at a predetermined angle, and the front end surface thereof is exposed in the accommodation chamber, and the irradiation light introduction member The front end surface is an irradiation end of the light, a reflected light absorber disposed outside the container on the opposite side of the light irradiation means 180 ° around the inflow port, and a substrate from the substrate in the storage chamber A reflected light trap having a reflected light deriving member for guiding reflected light from the accommodation chamber to the reflected light absorber, or a reflected light receiving element arranged outside the container, and reflection from a substrate in the accommodation chamber A reflected light deriving member for guiding light from the accommodation chamber to the reflected light receiving element; and the reflected light Reflected light receiving means including a reflected light intensity recording calculator for recording the intensity of reflected light detected by the light receiving element is disposed, and the reflected light deriving member has an axis centered from the substrate in the accommodating chamber. It is inserted from the upper surface of the upper lid toward the center of the upper surface of the substrate in the storage chamber at a predetermined angle so as to coincide with the optical axis of the reflected light, and its tip surface is exposed in the storage chamber. The front end surface of the reflected light deriving member is a light receiving end of reflected light, and the scattered light receiving element disposed outside the container by shifting the position around the inflow port by 90 ° from the light irradiation means. A scattered light deriving member that guides scattered light from the substrate in the accommodation chamber to the scattered light receiving element from the accommodation chamber, and a scattered light intensity recording calculator that records the intensity of the scattered light detected by the scattered light receiving element; Scattered light receiving means comprising: is disposed, and the scattered light deriving member is Inserted from the top surface of the upper lid toward the center of the top surface of the substrate in the storage chamber toward the center of the top surface of the substrate in the storage chamber so that its axis coincides with the optical axis of the scattered light from the substrate in the storage chamber, Is exposed in the storage chamber, and the front end surface of the scattered light deriving member is a light receiving end of the scattered light .

Water quality according to claim 2 is characterized in that it comprises Oite to claim 1, the light-receiving signal intensity or recording means for recorded over time the change of the light receiving means.

Water evaluation device according to claim 3, in claim 1 or 2, which is characterized in that the light-receiving signal intensity or the change of the light receiving means including an alarm means for generating an alarm signal when it reaches a predetermined value It is.

A water quality evaluation apparatus according to a fourth aspect of the present invention is the water quality evaluation apparatus according to any one of the first to third aspects, wherein the light irradiating means emits light of a specific wavelength, and the light receiving means detects the intensity of the light of the specific wavelength. It is what is characterized by.

Water evaluation method according to claim 5, meet water quality evaluation method for evaluating the quality of ultra pure water using the water quality evaluation apparatus according to any one of claims 1 to 4, the housing of the water quality evaluation device housing the electronic device substrate in the room, the inlet and through the outlet causes a continuous flow of test water consisting of ultra-pure water into the housing chamber, said light irradiating means to the housing chamber of the electronic device substrate And the water quality is evaluated by detecting the intensity of reflected light or scattered light from the electronic device substrate with the reflected light receiving means or scattered light receiving means .

The water quality evaluation method according to claim 6 is the electronic device substrate according to claim 5, wherein the electronic device substrate is a silicon wafer, a substrate in which a silicon oxide film, an aluminum thin film or a copper thin film is formed on the surface of the silicon wafer, a glass substrate, a GaAs wafer, or sapphire. A wafer is used.

  In the water quality evaluation method and apparatus of the present invention, light is irradiated toward the electronic device substrate in the container, the intensity of the reflected light or scattered light is detected, and the water quality is evaluated. If fine particles in the test water such as ultrapure water adhere to the surface of the electronic device substrate, the reflected light intensity decreases and the scattered light intensity increases, so the impurity concentration in the test water is detected from the reflected light intensity or scattered light intensity. Water quality can be evaluated.

  In the present invention, since the measurement is performed while the electronic device substrate is accommodated in the container, an error due to contamination does not occur. Further, the light irradiation means and the light receiving means have a simpler configuration and lower cost than the total reflection X-ray fluorescence analyzer. Furthermore, since the measurement is performed in a state where water has passed through or in a state where water is present in the container, a mechanism for rotating the electronic device substrate in the container at a high speed is unnecessary, and the container cost is low.

In the present invention, since so as to expose the light receiving end of light irradiation end and the light receiving unit of the light irradiation means in the housing chamber, directly light irradiated on the electronic device substrate, Ru can be accurately irradiated.

  In the present invention, the intensity or change of the received light signal detected by the light receiving means may be recorded with time so that the change in water quality with time can be confirmed.

  In addition, an alarm signal may be issued when the temporal change in the intensity or change of the received light signal reaches a predetermined value set in advance so that the deterioration of water quality such as ultrapure water can be known.

  Note that the measurement light may be either ultraviolet light or visible light. By using light having a specific wavelength, it is possible to increase measurement accuracy.

  Embodiments of the present invention will be described below with reference to the drawings.

  1 is a longitudinal sectional view of a water quality evaluation apparatus according to an embodiment, FIG. 2 is a top view of a substrate holding container of the water quality evaluation apparatus, FIG. 3 is a perspective view of a bottom plate of the substrate holding container, FIG. These are the schematic system diagrams which show the water quality evaluation method using this water quality evaluation apparatus.

[Electronic device substrate W]
As an electronic device substrate (hereinafter, simply referred to as a substrate) W used in the water quality evaluation method of the present invention, a silicon wafer, a silicon oxide film, an aluminum thin film, or a copper thin film is formed on the surface of the silicon wafer. Examples include a substrate, a glass substrate, a GaAs wafer, and a sapphire wafer. However, these are only examples, and other electronic device substrates may be used in the present invention.

[Water quality evaluation apparatus 10]
The water quality evaluation apparatus 10 in this embodiment includes a substrate holding container 11 including a bottom plate 12 having a storage chamber 12a for a substrate W and an upper lid 13 for closing the storage chamber 12a. The storage chamber 12 a is formed of a circular depression that is recessed from the upper surface of the bottom plate 12.

  In this embodiment, the substrate holding container 11 is made of a material that does not transmit light, for example, metal.

  Near the center of the upper lid 13, an inlet 14 is provided for allowing test water (ultra pure water) to flow into the storage chamber 12a. Near the center of the bottom surface of the storage chamber 12a, the storage chamber 12a is provided. An outlet 15 is provided for allowing the test water to flow out from the inside. A water supply pipe 16 is connected to the inlet 14, and a drain pipe 17 is connected to the outlet 15.

  Reference numeral 12b denotes a leg erected downward from the lower surface of the bottom board 12. The legs 12b are configured to support the substrate holding container 11 substantially horizontally when the substrate holding container 11 is disposed on a substantially horizontal plane.

  In this embodiment, the light irradiation device 30 that irradiates light toward the substrate W accommodated in the accommodation chamber 12a, the reflected light trap 40 that absorbs the reflected light from the substrate W, A scattered light receiving device 50 that receives scattered light from the substrate W is provided.

  The light irradiation device 30 includes an irradiation light source 31 arranged outside the substrate holding container 11, an irradiation light introducing member 32 for guiding light irradiated from the irradiation light source 31 into the storage chamber 12a, and the irradiation light source. And a power source 33 for supplying power to 31. In this embodiment, a laser light source is used as the irradiation light source 31. The irradiation light introducing member 32 is made of a hollow tube, a rod-shaped body made of glass or transparent resin, or the like. The irradiation light introducing member 32 is inserted from the upper surface of the upper lid 13 at a predetermined angle toward the vicinity of the center of the upper surface of the substrate W in the accommodation chamber 12a, and its tip surface (light irradiation end) is located in the accommodation chamber 12a. Is exposed. Light from the irradiation light source 31 passes through the irradiation light introducing member 32 and is irradiated near the center of the upper surface of the substrate W in the storage chamber 12a.

  The reflected light trap 40 is arranged around the inflow port 14 on the side opposite to the light irradiation device 30 by 180 °. The reflected light trap 40 includes a reflected light absorber 41 disposed outside the substrate holding container 11, a reflected light deriving member 42 that guides reflected light from the substrate W to the reflected light absorber 41 from within the storage chamber 12 a. It has. The reflected light deriving member 42 is also made of a hollow tube, glass, a transparent resin rod-like body, or the like, and is arranged at a predetermined angle from the upper surface of the upper lid 13 so that its axis coincides with the optical axis of reflected light from the substrate W. Then, it is inserted toward the vicinity of the center of the upper surface of the substrate W in the storage chamber 12a, and its front end surface (light receiving end) is exposed in the storage chamber 12a.

  The scattered light receiving device 50 is arranged around the inflow port 14 at a position shifted by 90 ° from the light irradiation device 30. The scattered light receiving device 50 includes a scattered light receiving element (not shown) arranged outside the substrate holding container 11 and a scattered light derivation that guides scattered light from the substrate W from the storage chamber 12a to the scattered light receiving element. A member 51 and a scattered light intensity recording calculator 52 that records the intensity of the scattered light detected by the scattered light receiving element over time are provided. The scattered light deriving member 51 is also made of a hollow tube, glass, a transparent resin rod-like body, or the like, and is arranged at a predetermined angle from the upper surface of the upper lid 13 so that its axis coincides with the optical axis of the scattered light from the substrate W. Then, it is inserted toward the vicinity of the center of the upper surface of the substrate W in the storage chamber 12a, and its front end surface (light receiving end) is exposed in the storage chamber 12a.

  In this embodiment, the water quality evaluation apparatus 10 includes an alarm device (not shown) that generates an alarm signal when the intensity of the scattered light detected by the scattered light receiving device 50 or the intensity change exceeds a predetermined value. ) Is provided.

  In the present invention, the irradiation light from the irradiation light source 31 may be either ultraviolet light or visible light. Alternatively, the light source 31 may emit light having a specific wavelength. In this case, the irradiation light source 31 itself may emit light of a specific wavelength, and the substrate W is irradiated with only light of a specific wavelength out of the irradiation light from the irradiation light source 31 via a spectroscope or a filter. You may comprise. Alternatively, the scattered light receiving device 50 may be configured to detect the intensity of light of a specific wavelength. By using light of a specific wavelength for measurement in this way, the measurement accuracy can be increased.

  The inner diameter of the circular storage chamber 12a of the bottom plate 12 is sufficiently larger than the diameter of the substrate W to be held. On the bottom surface of the storage chamber 12a, a plurality (three in this embodiment) of radial ridges 24 are provided at equal intervals in the circumferential direction as means for holding the substrate W. Each radial ridge 24 extends in the radial direction of the storage chamber 12a.

  The substrate W is held substantially horizontally on these radial rods 24 concentrically in the center of the storage chamber 12a with the plate surface facing upward. A step-shaped support base 25 having a step 26 on which the peripheral edge of the substrate W is placed is provided on the outer end portion of each ridge 24. The level difference of the level 26 corresponds to the thickness of the substrate W. In addition, a support portion 27 that supports the lower surface of the substrate W in the radial direction is provided in the middle of the extending direction of each flange 24.

  A plurality of protrusions 23 for positioning the upper lid 13 protrude from the upper surface of the bottom plate 12. These protrusions 23 are arranged at substantially equal intervals in the circumferential direction of the storage chamber 12a. The lower surface of the upper lid 13 is provided with a recess (not shown) with which the protrusions 23 are engaged. Reference numeral 28b denotes a bolt hole into which a bolt 28a for fixing the upper lid 13 to the bottom board 12 is screwed.

  When the substrate W is accommodated in the storage chamber 12a and the test water is introduced into the storage chamber 12a from the inflow port 14, the test water is supplied from the inflow port 14 to the center of the substrate W. The test water flows radially from the center toward the outer peripheral side at a substantially constant flow rate. Thereby, the test water can be brought into contact with the entire surface of the substrate W substantially uniformly.

  A male screw 16 a is formed on the outer peripheral surface on the downstream side of the water supply pipe 16, and a female screw (not shown) is formed on the inner peripheral surface of the inlet 14 to which the male screw 16 a is screwed. The water supply pipe 16 is connected to the inflow port 14 by the male screw 16a being screwed into the inflow port 14 through a sealing material (not shown). A male screw 17 a is formed on the outer peripheral surface on the upstream side of the drain pipe 17, and a female screw (not shown) on which the male screw 17 a is screwed is formed on the inner peripheral surface of the outlet 15. The male pipe 17a is screwed into the outlet 15 via a sealing material (not shown), so that the drain pipe 17 is connected to the outlet 15.

  Hereinafter, the connection between the male screw provided on one side and the female screw provided on the other side so as to be connected to each other is referred to as connection by screwing. Thus, by connecting by screwing, the airtightness of a connection part becomes favorable.

  The upstream side of the water supply pipe 16 is bifurcated into an introduction pipe 18 and a lead-out pipe 19. In this embodiment, the water supply pipe 16, the introduction pipe 18 and the lead-out pipe 19 are made of a series of T-shaped pipes, and the axial axes of the introduction pipe 18 and the lead-out pipe 19 are substantially straight. Thus, the water supply pipes 16 extend in a direction substantially orthogonal thereto. However, the introduction pipe 18 and the lead-out pipe 19 do not have to be in a straight line as long as they are bifurcated.

  Opening / closing valves 20 and 21 are connected to the leading ends of the introduction pipe 18 and the lead-out pipe 19, respectively. In this embodiment, ball valves with good airtightness when closed are used as the opening and closing valves 20 and 21. The introduction pipe 18 and the lead-out pipe 19 are connected to the on-off valves 20 and 21 by screwing. Reference numeral 18a denotes a male screw formed on the outer periphery of the leading end of the introduction pipe 18 and screwed into a downstream connection port (not shown) of the opening / closing valve 20 via a sealing material (not shown). A male screw formed on the outer periphery of the distal end of the tube 19 and screwed into an upstream connection port (reference numeral omitted) of the on-off valve 21 via a sealing material (not shown) is shown.

  Before the use point, a sampling tube 3 for supplying test water from the ultrapure water supply pipe 1 to the water quality evaluation apparatus 10 via the opening / closing valve 2 is branched. This sampling tube 3 is connected to the tube joint 4 by external fitting, band fastening or the like. The sampling tube 3 and the tube joint 4 constitute a test water supply pipe. The tube joint 4 is screwed into the upstream connection port (reference numeral omitted) of the open / close valve 20 of the introduction pipe 18. Reference numeral 4 a denotes a male screw formed on the outer periphery of the distal end of the tube joint 4 and screwed into the upstream connection port of the opening / closing valve 20.

  An open / close valve 22 is also connected to the downstream side of the drain pipe 17. In this embodiment, the opening / closing valve 22 is also a ball valve. The drain pipe 17 and the open / close valve 22 are also connected by screwing. Reference numeral 17 b denotes a male screw formed on the outer periphery of the downstream end of the drain pipe 17 and screwed into the upstream connection port (reference numeral omitted) of the opening / closing valve 22.

  The drain pipe 17 is an L-shaped pipe that extends downward from the outlet 15 and then bends at a substantially right angle from the middle. However, the shape of the water pipe 17 is not limited thereto.

  On the downstream side of the opening / closing valve 21 of the outlet pipe 19 and the downstream side of the opening / closing valve 22 of the drain pipe 17, drain pipes 5 and 6 for guiding the effluent water from the outlet pipe 19 and drain pipe 17 to the drainage system, respectively. Is connected. In this embodiment, the pipes 5 and 6 are also connected to the open / close valves 21 and 22 by screwing. Reference numerals 5 a and 6 a indicate male threads formed on the outer circumferences of the upstream ends of the pipes 5 and 6 and screwed into the downstream connection ports (not shown) of the on-off valves 21 and 22, respectively.

  However, since these pipes 5 and 6 are on the drain side, it is not necessary to consider the airtightness of the connections between the pipes 5 and 6 and the valves 21 and 22. Therefore, the connection between the pipes 5 and 6 and the valves 21 and 22 may not be by screwing. The connection at other locations may not necessarily be by screwing, but on the water supply side, it is preferably a screwing type with high airtightness.

  Next, a procedure for evaluating the quality of ultrapure water using the water quality evaluation apparatus 10 having such a configuration will be described.

  First, the board | substrate W is arrange | positioned in the storage chamber 12a, the upper cover 13 is covered on the bottom board 12, it fixes with the volt | bolt 28a, and the storage chamber 12a is closed.

  Next, the open / close valve 2 of the sampling tube 3, the open / close valves 20 and 21 of the introduction pipe 18 and the discharge pipe 19 are opened, and water is supplied into the introduction pipe 18, the discharge pipe 19 and the open / close valves 20 and 21, respectively. To clean.

  Next, the open / close valve 22 of the drain pipe 17 is opened to pass the test water into the storage chamber 12 a, and the test water is brought into contact with the substrate W.

  At this time, the flow rate of the test water is adjusted by adjusting the opening degree of the opening / closing valve 21 on the outlet pipe 19 side while keeping the opening / closing valve 20 on the introduction pipe 18 side at a constant opening degree. Although it is conceivable to adjust the flow rate of the test water by adjusting the opening degree of the open / close valve 20 on the introduction pipe 18 side, the valve constituent material is caused by friction of each part during the valve operation. There is a risk of elution in the test water or fine particles mixed into the test water. On the other hand, if the flow rate of the test water is adjusted by adjusting the opening degree of the open / close valve 21 on the outlet pipe 19 side, even if elution of constituent materials or mixing of fine particles occurs in the test water from the open / close valve 21. Since the opening / closing valve 21 is located on the downstream side of the water supply pipe 16, the supply water into the storage chamber 12a is not contaminated.

  In this way, light is irradiated from the light irradiation device 30 toward the substrate W in the storage chamber 12a in a state where water has passed through the storage chamber 12a, and the intensity of the scattered light from the substrate W by the scattered light receiving device 50. And the detected value is recorded over time by the scattered light intensity recording calculator 52.

  When impurities in the test water adhere to the surface of the substrate W, the greater the amount of adhesion, the lower the reflected light intensity from the substrate W and the scattered light intensity from the substrate W increases. Therefore, the quality of the test water (impurity concentration, etc.) can be evaluated from the intensity of the scattered light from the substrate W or its change with time.

  In this embodiment, when the intensity of the scattered light detected by the scattered light receiving device 50 or a change in the intensity exceeds a predetermined value, the alarm device issues an alarm signal and the water quality of the test water is below the standard. It is to inform you that there is.

  In this water quality evaluation method, since the measurement is performed while the substrate W is housed in the substrate holding container 11, there is no error in the measurement result due to contamination by outside air or the like. In addition, the light irradiation device 30 and the scattered light receiving device 50 (and the reflected light trap 40) have a simpler configuration and lower cost than the total reflected light X-ray analyzer.

  Furthermore, in this water quality evaluation method, since the measurement is performed in a state where the water is passed through the storage chamber 12a in which the substrate W is accommodated, it is not necessary to dry the substrate W, and the measurement operation can be performed easily and quickly on site. This also eliminates the need for a mechanism for rotating the substrate W in the accommodation chamber 12a at a high speed and drying the substrate W as described in JP-A-2001-237289, and the container cost is low.

  As in this embodiment, by configuring the test water to be extracted from the ultrapure water supply pipe 1 before the use point, it is possible to evaluate water having the same quality as the water actually used.

  It is desirable that this water quality evaluation is performed periodically at regular intervals.

  In the above embodiment, the water quality is evaluated from the intensity of the scattered light from the substrate W and its change over time. For example, instead of the reflected light trap 40, the same structure as the scattered light receiving device 50 is used. The reflected light receiving device may be installed, and the water quality may be evaluated by measuring the intensity of reflected light from the substrate W and its change with time.

  Further, when the surface of the substrate W is made of a material that absorbs light of a specific wavelength, the water quality is evaluated by measuring the amount of absorption or absorption of the light of the specific wavelength in the reflected light or scattered light from the substrate W. It is also possible to do this.

  Water quality evaluation was performed using the water quality evaluation apparatus 10 described above.

[Example 1]
A silicon wafer was accommodated as a substrate W in the substrate holding container 11, and ultrapure water having a resistivity of 18.2 MΩ · cm and a TOC concentration of 1 ppb was passed through the container 11 as test water. In this state, laser light is irradiated from the light irradiation device 30 toward the silicon wafer in the storage chamber 12a, and the intensity of the scattered light from the silicon wafer is detected by the scattered light receiving device 50, and the detected value is scattered. Recording was performed with the light intensity recording calculator 52 over time.

  After 40 hours from the start of water flow, the scattered light intensity became 10 times that immediately after the start of water flow.

  This is because the sample water passed through the container 11 for 40 hours caused impurities in the sample water to adhere to the surface of the silicon wafer, which roughened the surface of the silicon wafer, thereby increasing the intensity of scattered light from the silicon wafer. It is shown that.

[Example 2]
The ultrapure water used in Example 1 was mixed with primary pure water having a resistivity of 17.0 MΩ · cm and a TOC concentration of 8 ppb, and passed through the substrate holding container 11 containing a silicon wafer. The water quality of the mixed water showed a resistivity of 18.0 MΩ · cm and a TOC concentration of 2 ppb. In this state, laser light is irradiated from the light irradiation device 30 toward the silicon wafer in the storage chamber 12a, and the intensity of the scattered light from the silicon wafer is detected by the scattered light receiving device 50, and the detected value is scattered. Recording was performed with the light intensity recording calculator 52 over time.

  As a result, 5 hours after the start of water flow, the scattered light intensity became 10 times that immediately after the start of water flow.

  This measurement result clearly reflects the increase in the TOC concentration in the test water, and shows the effectiveness of the method and apparatus of the present invention in water quality evaluation.

It is a longitudinal cross-sectional view of the water quality evaluation apparatus which concerns on embodiment. It is a top view of the substrate holding container of the water quality evaluation apparatus. It is a perspective view of the bottom board of a substrate holding container. It is a schematic systematic diagram which shows the water quality evaluation method using the water quality evaluation apparatus of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 Sampling tube 4 Tube joint 10 Water quality evaluation apparatus 11 Substrate holding container 12 Bottom board 12a Accommodating chamber 13 Upper lid 14 Water supply port 15 Drainage port 16 Water supply pipe 17 Drainage pipe 18 Introduction pipe 19 Outlet pipe 20-22 Open / close valve 30 Light irradiation device 40 Reflection Optical trap 50 Scattered light receiving device 52 Scattered light intensity recording calculator W substrate

Claims (6)

A container having a storage chamber for storing the electronic device substrate, and having an inlet and an outlet for circulating test water in the storage chamber;
Light irradiating means for irradiating light toward the electronic device substrate housed in the housing chamber;
Receiving reflected light or scattered light from the electronic device substrate Ri name and a light receiving means for detecting the intensity,
The light emitting end of the light irradiating means and the light receiving end of the light receiving means are respectively exposed in the accommodation chamber,
The container has a bottom plate having the storage chamber and an upper lid for closing the storage chamber, and the storage chamber is formed of a circular depression recessed from the upper surface of the bottom plate,
The inflow port for allowing the test water to flow into the storage chamber is provided at the center of the upper lid, and the outlet for discharging the test water from the storage chamber is provided at the center of the bottom surface of the storage chamber. And
The light irradiation means includes an irradiation light source disposed outside the container, and an irradiation light introducing member for guiding light irradiated from the irradiation light source into the storage chamber,
The irradiation light introducing member is inserted at a predetermined angle from the upper surface of the upper lid toward the vicinity of the center of the upper surface of the substrate in the accommodation chamber, and a tip surface thereof is exposed in the accommodation chamber, and the irradiation light introduction The tip surface of the member is an irradiation end of the light,
Around the inlet, 180 ° opposite to the light irradiation means,
A reflected light trap comprising: a reflected light absorber disposed outside the container; and a reflected light deriving member that guides reflected light from the substrate in the storage chamber to the reflected light absorber from the storage chamber; or
A reflected light receiving element disposed outside the container; a reflected light deriving member for guiding reflected light from the substrate in the housing chamber to the reflected light receiving element from the housing chamber; and a reflection detected by the reflected light receiving element Reflected light receiving means comprising a reflected light intensity recording calculator for recording the light intensity
Is placed,
The reflected light deriving member is directed toward the center of the upper surface of the substrate in the receiving chamber at a predetermined angle from the upper surface of the upper lid so that the axis of the reflected light deriving member coincides with the optical axis of the reflected light from the substrate in the receiving chamber. The front end surface is exposed in the housing chamber, and the front end surface of the reflected light deriving member is a light receiving end of the reflected light,
Shift the 90 ° position around the inlet from the light irradiation means,
A scattered light receiving element disposed outside the container; a scattered light deriving member that guides scattered light from the substrate in the housing chamber to the scattered light receiving element; and scattering detected by the scattered light receiving element. Scattered light receiving means comprising a scattered light intensity recording calculator for recording the light intensity
Is placed,
The scattered light deriving member is directed toward the center of the upper surface of the substrate in the receiving chamber at a predetermined angle from the upper surface of the upper lid so that its axis coincides with the optical axis of the scattered light from the substrate in the receiving chamber. A water quality evaluation apparatus , wherein the tip end surface of the scattered light deriving member is exposed to the scattered light receiving end . Oite to claim 1, the water quality evaluation apparatus characterized by comprising a recording means for recorded over time the light-receiving signal intensity or the change of the light receiving means. 3. The water quality evaluation apparatus according to claim 1, further comprising alarm means for generating an alarm signal when the intensity of the received light signal of the light receiving means or a change thereof reaches a predetermined value. In any one of claims 1 to 3, the light irradiating means serves to irradiate light of a specific wavelength, the light receiving means is characterized in that for detecting the intensity of light of the specific wavelength Water quality evaluation device. Met claims 1 to water quality evaluation method for evaluating the quality of ultra pure water using the water quality evaluation apparatus according to any one of 4,
Housing the electronic device substrate in the housing chamber of the water quality evaluation device, causes continuously circulating test water consisting of ultra-pure water into the housing chamber through the inlet and the outlet,
Light is irradiated to the light irradiation means in said housing chamber of the electronic device substrate, the detected intensity of the reflected light or scattered light by the reflected light receiving means or scattered light receiving means from the electronic device substrate quality evaluation Water quality evaluation method characterized by performing. 6. The water quality according to claim 5, wherein the electronic device substrate is a silicon wafer, a substrate in which a silicon oxide film, an aluminum thin film or a copper thin film is formed on a surface of the silicon wafer, a glass substrate, a GaAs wafer, or a sapphire wafer. Evaluation methods.

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