JP2002511613A - Chemical process automatic control system - Google Patents

Abstract

(57) Abstract: A chemical delivery system for a chemical liquid containing a plurality of predetermined chemical components comprises an analyzer for determining a ratio of one of the predetermined chemical components in the chemical liquid to be delivered. Is used. The analyzer is fed with a precise volume of chemical liquid sample by a precision analysis sample feeder in the form of an automated sample syringe. Information about the determination by this analyzer of at least one proportion of said predetermined chemical component in the chemical liquid to be delivered is stored in a control unit which can be realized by a microcomputer. The controller controls a replenisher that delivers a precisely controlled amount of the predetermined chemical component to a source of chemical liquid. The analysis is repeated and values and trends are checked to ensure that the results are accurate, valid and iterative. During the titration analysis, a multi-step operation is performed to control the titration, especially near the end point, to ensure accuracy. After each analysis, a purging process is performed using a purge gas such as air and a rinsing solvent to force removal of the previous sample. The sample syringe is cycled repeatedly until the previous sample has been completely removed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION

The present invention relates generally to chemical processing systems. More particularly, it relates to a system for automatically monitoring and replenishing fluid levels in chemical processing systems such as chemical baths. Further, the invention described herein relates to an automatic online chemical bus control system. This system can be used, for example, in an automatic chemical bath control system for a chemical mechanical planarization process.

[0002]

[Prior art]

Chemical mechanical planarization or polishing (CMP) processes are widely used in the manufacture of microcircuits. A typical CMP process utilizes an abrasive slurry diluted with a diluent. Oxidant slurry may be used. Maintaining slurry quality is essential to maximize equipment manufacturing. Slurry properties, such as pH, specific gravity, solids weight percent, slurry particle size distribution, etc., must be dynamically measured to ensure that the slurry is stable. That is, the slurry must be resistant to settling and agglomeration, and free of impurities such as aggregates of slurry particles, foreign matter, adsorbed carbon dioxide, and ionic impurities.

[0003] The monitoring and measurement of the slurry characteristics and the analysis of chemical components can be performed online or offline. While online measurements provide real-time data,
Many analytical instruments are not easily adapted for on-line sampling, and users have opted for off-line analytical techniques. In addition, online analytical instruments frequently require maintenance and calibration for proper operation. Therefore, there is a need for a technique for improved automatic online CMP wrestling control.

[0004] One of the most challenging problems with control in current CMP processes is mechanical operation. With further miniaturization of the circuit, the mechanical operation is too coarse to control to the required fine resolution. Therefore, new CMP processes rely more heavily on developments in chemical polishing rather than mechanical polishing. However, chemical polishing requires greater control of the chemical bath. Many chemicals added are dynamic in nature and deplete with use, especially in the case of hydrogen peroxide, which degrades over time and changes in feedstock concentration. This change and decomposition
Affects both the finishing (mixing) and dispensing (or holding) steps in slurry preparation and usage. The only way to properly control the chemical bath is frequent and accurate chemical analysis and replenishment.

Additionally, the chemical composition of the CMP chemical bath should be monitored and replenished as needed. Examples include Semi-Sperse® W2000, Cabot Corporation, Auror
a, IL tungsten CMP slurry is a non-metallic slurry, mixed with an oxidizer, useful for polishing tungsten and titanium. However, the oxidant (hydrogen peroxide) concentration must be monitored and replenished. Ideally, monitoring and replenishment should be automated online. The weight percentage of hydrogen peroxide in Semi-Sperse® W2000 is tested using reductive titration with an oxidizing agent such as cerium sulfate (Ce (SO ₄ ) ₂ ), potassium permanganate (KMnO ₄ ) be able to. But,
To be useful, automatic titration / control systems must be as reliable, accurate, and reproducible as or better than manual titration methods. To this end, a platinum ORP sensor, a gold ORP sensor, a temperature sensor, and a color sensor can be used to detect a differential endpoint (ie, an inflection point). Therefore, there is a need for a technique for accurate, reliable and reproducible in-line analysis of chemical CMP baths and automatic replenishment of depleted bath components.

[0006]

[Problems to be solved by the invention]

It is an object of the present invention to provide a chemical analysis and control system that protects a controlled process from illogical consequences.

[0007] It is another object of the present invention to provide a chemical control system that achieves accurate and variable delivery of water and reagents.

[0008] It is another object of the present invention to provide a chemical analysis system that achieves continuous titration vessel level sensing.

It is a further object of the present invention to provide a chemical analysis system that achieves automatic detection of problems associated with titration vessel level changes, such as insufficient reagents, low water pressure, disabled valves, and the like.

It is a further object of the present invention to provide a chemical analysis and control system that alerts a user, for example, to potential problems in a system that requires cleaning or preventative maintenance.

It is a further object of the present invention to provide a chemical analysis system that provides a user with an indication of changes in the daily performance of the system.

[0012] Another object of the present invention is to provide a chemical analysis system that automatically and safely replenishes a predetermined amount of chemicals.

It is a further object of the present invention to provide a chemical analysis system that minimizes water consumption between cleaning and filling of the titration vessel.

It is another object of the present invention to provide a chemical analysis system that achieves continuous level measurement of a wide range of corrosive caustic solutions in a small space.

It is a further object of the present invention to provide a chemical sampling system capable of withdrawing a representative chemical sample from a stationary tank several hundred feet away and achieving accurate and repeatable chemical property measurements of the withdrawn sample. It is to be.

Yet another object of the present invention is to allow a representative chemical sample to be withdrawn from a stationary tank several hundred feet away without requiring the installation and operation of a pump in that tank, and that the tank can be used for another one. It is to provide a chemical sampling system, which may be a tank forming two recirculation loops.

Yet another object of the present invention facilitates accurate finishing (mixing) of peroxide slurries and other mixtures by analyzing and compensating for feedstock changes and decomposition.

A further object of the present invention is to provide the ability to re-store chemicals not used in the test in the tank from which they were drawn, thereby preventing waste of the unused chemicals. That is.

It is a further object of the present invention to provide a chemical analysis system that can accommodate a wide range of amounts and concentrations of samples and can increase the versatility of the system.

It is another object of the present invention to provide a porous wood, ceramic for flow restriction, electrolyte preservation, without having to bother with ion migration problems associated with gel-filled control cell electrolytes. It is an object of the present invention to provide a chemical analysis system with a control cell having an extended period of zero potential electrical connection to the solution without the use of a plastic or plastic plug.

Another object of the present invention is to measure the concentration of a plurality of mixed and retained mixtures, measure the level of each mixture, calculate the volume of each mixture, and then, by analysis or over time. Accordingly, it is an object of the present invention to provide a chemical treatment system which maintains the accuracy by adjusting the replenishment amount determined in accordance with the solution amount in the tank.

It is another object of the present invention to provide a chemical control system for level monitoring, chemical analysis and peroxide control in a mixing or dispensing (or holding) tank used for preparing a CMP slurry. .

It is an object of the present invention to provide a chemical processing system with electronic communication for communicating data including information related to analysis results, status, errors, replenishment amounts, etc., to a remote host operator interface.

[0024]

[Means for Solving the Problems]

These and other objects are addressed by the titration analyzer aspect of the present invention, which comprises a microprocessor-based system for performing various wet chemical analysis procedures such as direct pH measurement or pH, ORP or colorimetric titration. Is achieved by The analyzer of the present invention also performs sample search, sample preparation, cleaning, data manipulation, auto-calibration, and diagnostics.

When an analysis is initiated by the automatic manager portion of the system, the analyzer performs a series of tests without the need for further instructions by a human operator. The system may be implemented on a personal computer. Each analysis is automatically repeated, and the results of the analysis are evaluated statistically, ensuring that the final report results can be repeated with user-specified tolerances. The end result is then validated by the computerized manager by performing a series of range and trend checks.

The computerized manager allows a user to view and modify analytical configuration parameters such as sample volume, dilution volume, tolerance, and the like. Further, the computerized manager allows the user the flexibility to operate various valves, syringes and mixers, and obtain electrode and detector displays. These devices are described in detail below.

According to one aspect of the present invention, an online automatic analyzer eliminates the need for manual analysis and provides analytical accuracy and repeatability over manual methods and conventional instruments. The system in some aspects of the invention operates in conjunction with a replenishment system, with automated control as well as process bus monitoring.

The analyzer of the present invention automatically extracts samples from a plurality of process buses and performs a chemical analysis of process chemistry. The result of the analysis is sent to the manager system.
Self-calibration and consultation routines are programmed in the analyzer to ensure consistent and reliable system performance.

As shown, the analyzer of the present invention includes a precision replenishment system that receives a drug addition instruction from the manager system. According to the present invention, the medicine addition instruction,
Based on analytical results, amp-minutes, process time (bus time), or manually entered operator commands. The manager system determines the specific pump to be activated and the specific valve to be opened and closed and communicates to the replenisher control system. A precision flow sensor is used to monitor the added volume. The system is designed to maintain residual chemicals and report chemical usage by process batches. A digital keypad is used to allow remote control of this entire system operation.

In one embodiment of the invention, the PC interface is a Microsoft Windows ™ based system that uses graphical icons to simplify the operation of the system. The computerized manager communicates with all of the other modules written via the RS-422 interface and processes the received data according to predetermined operator settings. Commands generated by the computerized manager initiate control functions and operator alerts. In a further aspect of the invention, the computerized manager includes a database that provides a history of all parameters monitored by the system. Such historical information can be used to generate reports available from the computerized manager. Thus, for time frames, parameters, buses, chemicals or modules, the operator always has
Various tables, graphs, charts and status reports can be printed.

Overview of Principles of Operation The analyzer of the present invention performs three basic functions, specifically, sampling, analysis, and cleaning. Diagnostics, automatic calibration, and calculations are included in these functions.

Sampling Sampling involves withdrawing liquid from a tank, sample loop, or grab sample outlet and sending it to an analysis cell. For titration and / or analysis where a precise amount of sample is required, the sample syringe is circulated to pump the sample into it and purge any other liquid. The sample is cycled through the reaction cell beaker several times to ensure that the sample is representative of the liquid in the tank. During this phase, both the timer and the sample appearance detector are used to verify that the sample has arrived in a reasonable time to perform the analysis. Before the last dose of sample has been dispensed, the beaker is completely clean. For analysis where the sample is tested directly without dilution, the liquid is pushed into the analysis beaker by the pressure of this sample loop or by being drawn by an eductor.

Analysis After the sample has been delivered to the cell, an analysis is performed. Titration analysis, in one embodiment of the present invention, may be performed with any conditioning reagents fed by gravity through a solenoid valve. The titrant is delivered by a syringe that operates under the control of a stepping motor. The titrant is added continuously, during which an analog display is provided at predetermined intervals to find the end point. When the end point is found, the beaker is cleaned and the test is repeated until the result is within the user specified tolerance. In a workable embodiment of the invention, at least
Three repetitions are required, with a maximum of nine allowed. As soon as the test results meet the continuous analysis stop condition, the analyzer performs a thorough cleaning to avoid cross-contamination.

Cleaning The cleaning process rinses all analyzer configurations that have come into contact with the sample solution. This begins with an air purge through the rotary valve and filter. If the sample is not cleared from the entire line, an error condition is generated for the next analysis, alerting that the air pressure is low. Once purged with air, the rinsing water is switched to a spray condition to maximize the rinsing effect, and if used, the sample syringe is circulated until it is clean. Depending on the process in which the analyzer is being used, there may not be a water rinse of the sampling line. Following this, the direct filling line to the beaker is cleaned.

Grab Sample A bottle sample is provided to the analyzer for analysis at the grab sample shipper port. In order to obtain optimal results, the sample concentration must be within a certain range (alarm limit) of the parameter being tested.

PH Electrode Calibration A pH calibration is performed when a user-specified time has elapsed since the last pH calibration and prior to analysis using a pH electrode. The calibration uses two pH buffers to determine the slope and offset of the pH electrode. Once a stable reading is obtained with one buffer, the beaker is cleaned and another buffer reading is taken. The value of the slope is sent to the automated manager so that the operator can know the status of the electrodes. The slope and offset values are retained by the analyzer to convert the voltage reading to a pH value. The frequency of calibration is set through an analysis configuration table register entitled "Calibration Valid Time".

ORP Electrode Calibration ORP electrodes are used for differential rather than absolute titration, so no calibration is required. However, determining the sensitivity of the electrode is desirable because it can vary with use. The electrode sensitivity, calculated as the ratio of the actual response to the ideal response, is reported after each analysis and can be viewed with an automated manager along with other analyzer parameters.

ISE Methodology and Calibration Ion-selective electrodes (ISE) are used to measure a variety of electrolytes using standard addition methods. In a standard addition method, a known amount of a standard solution containing a known concentration of an electrolyte is sequentially added to a solution of an unknown concentration. The electrode voltage is measured after each addition. As the ion selective electrode increases the signal, it is possible to extrapolate to a point of zero electrolyte concentration to determine the amount of electrolyte in the original sample.

Three to five additions are performed such that the concentration is approximately doubled for each addition. Thus, the change in voltage between additions, DE, is large enough to give accurate results. A change of about 20 mV or more is desirable and should not be less than 5 mV. The higher the value of DE, the greater the repeatability of the analysis. In addition, high concentration standards are most preferred because they minimize dilution of the test solution. (Ion selective electrodes are also sensitive to solution ionic strength.) The standard solution addition method is accurate and reproducible. This eliminates the need to prepare a calibration standard that makes the background solution (matrix) the same as the unknown. The basic assumption using standard (known) addition is that the matrix has the same effect on the added electrolyte as it does on the original electrolyte in the unknown sample.

Turbidity Probe Methodology and Tuning Turbidity sensors are used to measure titrations having 1) a concentration proportional to turbidity, and 2) a turbidity (cloudy) endpoint. The proportional method requires calibration to prove the correlation between turbidity and concentration. Sulfate measurement (as barium sulfate)
It is an example of this type of measurement.

The example of turbid endpoint titration is used for cyanide in plating solutions. This method titrates a solution of unknown cyanide concentration with silver nitrate. When all of the cyanide is consumed with silver ions, the excess silver ions combine with the iodide indicator, forming a cloudy precipitate in the beaker. This cloud is detected by the turbidity sensor and generates a signal at the end of the titration. This increase in turbidity appears graphically as an elbow or a sharp upward curvature in turbidity.

Due to the endpoint method, the turbidity probe does not require calibration except when the probe is replaced. This is due to the fact that this titration is not absolute, but seeks for a relative change. The resistor connected to the probe is set to provide sufficient sensitivity to detect even slight turbidity. By adjusting the detection values in the analysis configuration table, the titration can be adjusted to match the operator's first observation as the endpoint. The endpoint can be set anywhere from almost invisible turbidity to very cloudy.

[0043]

[Summary of the Invention]

According to a first system aspect of the present invention, there is provided a chemical control system for a chemical solution containing a predetermined chemical component. According to this aspect of the invention, the analyzer determines one proportion of the predetermined chemical component in the chemical solution. A sample of the chemical solution is sent to the analyzer with a precision sample feeder to the analyzer. Information about the analyzer's determination of one of the predetermined chemical components in the chemical solution to be delivered is received by the controller. The control device can be realized by a microcomputer. A replenisher responsive to the controller delivers a controlled amount of the predetermined chemical component. A controlled amount of this chemical component is pumped into a tank or container holding the chemical solution.

In one embodiment of the invention, the analyzer is a titrator system. Some properties of the sample are monitored by one or more sensors or electrodes, depending on the addition of the reagent.

In some embodiments of the present invention, the analyzer includes a reaction cell that receives a sample of the chemical solution from a precision analyzer sample feeder. In an embodiment of the present invention, the electrodes measure predetermined electrical properties of the chemical solution, and the reaction cell is a glass beaker. The sensor may be a pH electrode, an ORP electrode, an ion selective electrode, or a turbidity sensor.

The present invention can monitor slurry. In that embodiment, one of the predetermined chemical component in the slurry is H ₂ O _2. The delivery of the chemicals takes place through a global loop that distributes the chemical solution in the plant. The global loop may be pressurized.

In some embodiments, the controller comprises a display for displaying information in response to a decision made by the analyzer. Further, the display device includes a plurality of predetermined parameters of the chemical control system, diagnostic conditions of the chemical control system, operation history of the replenishment device, information related to the history of system failure, information on calibration of the chemical sensor, information on chemical products, Information on the volume of the chemical solution in the dispensing device, as well as additional system parameters and their history can be displayed.

In another embodiment, the liquid level in each solution tank is pumped through an orifice from a pressure regulator to reduce the head pressure of a gas such as N ₂ exiting a tube immersed in each solution tank. Monitored by monitoring. The pressure of the monitor gas through the orifice corresponds to the liquid level. The pressure of the monitoring gas is maintained generally between 1 and 15 psi, preferably between 2 and 10 psi.

In a highly preferred embodiment of the invention, the precision analyzer sample feeder comprises an eductor for drawing a sample into the analyzer. This eductor creates a negative pressure in the sample line.

The analyzer is purged by the purge system after recording each reading. In one embodiment, the purge system includes a gas purge valve that controls a pressurized purge gas to purge the analyzer. In addition, some embodiments include a rinse solvent purge valve that controls the flow of rinse solvent to purge the analyzer. The rinse solvent may clean the gas purge valve as well as the analyzer.

According to a further system aspect of the present invention, there is provided a chemical control system for a chemical solution containing a predetermined chemical component, comprising a precision analyzer sample for delivering a precise volume sample of the chemical solution. It has a feeding device. The precision sample is placed in the reaction cell, and a precise analyzer reagent delivery device delivers a precise amount of the predetermined reagent to the reaction cell. Here, typically, the characteristics of the chemical solution are measured by a sensor during the addition of the reagent. Information about the properties of the chemical solution measured by the sensor is received by the controller and stored for analysis. This data is then used by the control device to control the refill device. The replenisher adds a controlled amount of a predetermined chemical component to a source of the chemical solution.

The sample of the chemical solution is sent to the reaction cell via the sample line, and a detection device is provided to detect the presence of the chemical solution in the sample line. In one embodiment, a proximity sensor or optical sensor is located near the sample line. Thus, the sensor sends a signal to the controller indicating that a chemical solution is available.

In a highly preferred embodiment of the invention, said precision analyzer sample feeder comprises a syringe. The syringe is operated by a controllable drive including a drive motor and a control circuit. Preferably, the drive motor is a known stepping motor.

As already mentioned, when the analysis of the chemical solution is completed, the reaction cell and the sample line are purified by a purifier using a purge gas. Further, the purifier uses a rinse solvent. The rinsing solvent may be water, and in some embodiments of the present invention, is provided in a jetting manner to maximize the rinsing effect. The purifier also circulates through the sample syringe until the previous sample has been removed.

According to a first method aspect of the present invention, there is provided a method for analyzing a chemical solution having a first chemical composition in a tank. This method is a step of sending a sample of the chemical solution having the first chemical composition to an analysis cell, and performing a titration analysis on the chemical solution having the first chemical composition sent to the analysis cell, Controlling a syringe so as to feed the titrant into the chemical solution having the first chemical composition sent to the analysis cell; and analyzing a predetermined chemical property of the chemical solution. Determining the end point of the titration analysis; and performing a purification procedure.

[0056] In one embodiment of the method of the present invention, the feeding step includes the step of:
Includes the further step of delivering a predetermined amount of sample of a chemical solution having a chemical composition.
In a further embodiment, delivering the sample comprises changing the speed at which the performing the titration analysis is performed. This changing step is performed according to the step of determining the end point of the titration analysis. In the first stage, the titration analysis is performed in inverse proportion to the rate of change of the monitoring signal. However, as the end point of the titration analysis approaches, the feed rate changes. In short, in the early stages of the titration, the titrant is pumped at the maximum possible rate without pumping faster than the reaction can take place and without overshooting the endpoint. However, as the end point is approached, the change per unit volume of titrant added to the system switches to the second stage, as indicated by the increase in signal from the sensor. In this second stage, the rate of addition of the titrant is constant and slow, and the response of the sensor can change freely beyond the inflection point. This is done to give speed accuracy, since the changing speed appears to affect or shift near the end point and the titration is less.

In another embodiment of the present invention, the pumping step includes purging all liquid associated with the previous sample from the sample loop. In this manner, the next sample to be delivered will indicate the current content of the chemical solution being delivered.

The sending step includes a step of detecting sending a sample of the chemical solution having the first chemical composition to the analysis cell. This step is performed in some embodiments using a proximity sensor or a light sensor, as described above. In addition, the time for feeding the sample is also measured. If the sample has not become available within a predetermined maximum time, a misadjustment is signaled.

In yet another embodiment of the present invention, performing a titration analysis includes delivering a conditioning reagent. In some embodiments, the delivery of such reagents is via a gravity controlled delivery device.

In some embodiments, controlling the syringe that carries the titrant comprises controlling a stepping motor drive coupled to the syringe. An advantage of using a syringe in the present invention is that it allows precise control over the amount of titrant or sample fed into the reaction cell. Further, by controlling the stepping motor driving device, it is possible to control the feeding speed.

In yet another embodiment of the method of the present invention, the steps of monitoring a predetermined property of the chemical solution and determining the end point of each titration analysis are repeated. These steps are repeated until it is established that the results of the titration analysis are repeatable within predetermined parameters. In one embodiment, these steps are performed approximately three to nine times.

As indicated above, after performing the titration analysis, a purification procedure step is performed that includes pushing purge air through a filter through which the chemical solution having the first chemical composition has passed. In some embodiments, all sample lines and reaction cells are also purged.
Further, circulation is performed on the sample syringe until the sample syringe is cleaned from the previous sample. In one embodiment, the pressure of the purge gas is monitored and an error alert is issued if the pressure falls below a predetermined pressure. In addition, a rinsing liquid that can use water flows through the filter and the sample line connected to it.

There is a step of calibrating the pH electrode before performing the step of performing the titration analysis, comprising: performing a first pH reading on the pH electrode using a first pH buffer; Taking a second pH reading at the pH electrode using the pH buffer of 2 and determining a slope value and an offset value for the pH electrode. In another embodiment, an ORP electrode is provided. In this embodiment, performing the titration analysis includes performing a titration difference analysis. Further, there is a step of determining the sensitivity of the ORP electrode.

In some embodiments, determining the endpoint of the titration analysis comprises determining the turbidity endpoint. This involves using a turbidity sensor to determine the turbidity endpoint. As usual, this embodiment further comprises the step of titrating a solution of unknown cyanide concentration, which may use silver ions. Determining the turbidity endpoint of the titration using the turbidity sensor can include determining a change in the rate of change in turbidity of the chemical solution.

According to yet another method aspect of the present invention, there is provided a method for analyzing a chemical solution having a first chemical composition in a tank, wherein a sample of the chemical solution having the first chemical composition is sent to an analysis cell. And a step of performing ion selective analysis on the chemical solution having the first chemical composition sent to the analysis cell, wherein the chemical solution having the first chemical composition sent to the analysis cell has an electrolyte of a known concentration. Feeding a predetermined amount of the standard solution having a plurality of times, and after each feeding of the predetermined amount of the standard solution, the predetermined chemistry of the chemical solution having the first chemical composition sent to the analysis cell. -Selective analysis step including the step of measuring the potential of an ion-selective electrode in accordance with the characteristic characteristics; and the amount of electrolyte in a chemical solution having a first chemical composition sent to the analysis cell. A determining step, the method comprising containing the extrapolating step the measured values of a plurality of electrode potential at the point set in advance of the electrolyte concentration, and determining the amount of electrolyte is provided.

In one embodiment of this method of the invention, the step of delivering the predetermined amount of the expanded solution a plurality of times comprises delivering the predetermined amount of the standard solution approximately two to six times. In another embodiment, the amount of the standard solution having a known concentration of electrolyte is predetermined, thereby having a first chemical composition delivered to the analytical cell after each delivery of the predetermined amount of the standard solution. In the step of measuring the potential of the ion-selective electrode according to a predetermined chemical property of the chemical solution, the difference between the sequentially measured potential values is approximately 5 mV.
４０40 mV. The difference between the sequentially measured potential values is about 5 mV-
Preferably it is 30 mV, most preferably about 20 mV.

In another embodiment of this method of the invention, there is the step of reducing the speed at which the step of delivering the predetermined amount of the standard solution multiple times is performed. This improves the accuracy of determining the end point of the titration.

In yet another embodiment, the extrapolating step includes extrapolating the measured values of the plurality of electrode potentials to a zero point of the electrolyte concentration. In yet another embodiment, in the step of feeding the predetermined amount of the standard solution having the known concentration of the electrolyte a plurality of times, the concentration of the electrolyte in the standard solution is higher than the concentration of the electrolyte in the chemical solution having the first chemical composition. high. This reduces the dilution of the chemical solution having the first chemical composition.

[0069]

BEST MODE FOR CARRYING OUT THE INVENTION

In one aspect of the invention, the analyzer performs sensor differential tracking and alerting. The analysis uses a "differential" endpoint to avoid dependence on the absolute or compensated value of the sensor. When chemical equilibrium is reached during the titration, large swings occur in the sensor readings. This difference or increased rate of change is sought to determine that the end point of the titration has been reached. By tracking, reporting, and alerting of required sensor differentials, a user can be alerted to potential problems and, if necessary, choose to perform cleaning or preventative maintenance.

After performing the calibration process, the system of the present invention analyzes and sifts the data. Certain embodiments of the analyzer of the present invention do not accept the results of one analysis as correct and use the results for process control or feedback, but rather repeat at least two or more analyses. , Ensuring that the value is recoverable. Thereafter, the results are checked to determine if the values are within a predetermined range and to ensure that the values are valid.
If the value is iterative and valid, it is considered highly likely to be representative. Some features of the data sieving method of the present invention are as follows.

1. The end result is not just based on the average of many tests.

[0072] 2. The tolerance between each test is limited to a maximum value that can be predetermined, so that the accuracy can be selected.

[0073] 3. Limiting the maximum number of tests (typically up to nine) terminates unsuccessful attempts and alerts the operator to current or impending malfunction of the device.

This method logic protects the process under control from spurious results and gives the user instructions to execute daily on the machine. Increasing the number of tests before reaching the final result is a good warning that maintenance is required.

According to another aspect of the present invention, the automatic correction of the replenishment amount is performed based on the amount of the liquid in the storage tank. Adjustment of the calculated batch volume is advantageously made based on the current tank level reading.

The safety of the process is increased by setting a safe limit for replenishment. Replenishment is limited, regardless of the amount shown in the calculations. One of the safety features of the present invention
In performing one, the analyzer / controller goes through several increments towards the targeted replenishment. In particular, if the result is a large deviation from the target.

According to yet another aspect of the present invention, rinsing and filling of the beaker is performed at high speed and in small volumes (
Consumption) by spraying. The use of a spray rinse is advantageous because it facilitates rapid cleaning and filling of the beaker while minimizing water consumption. In most chemical analysis industries, time and water are important resources to save.

The agitation speed in the titration vessel of the chemical treatment system varies according to the set control parameters to achieve maximum mixing and cleaning while minimizing foaming and air entrapment. By varying the stirring speed, various functions can be optimized throughout the titration and washing steps. The titration vessel is sealed except for a drain / overflow tubing connected to the drain via an overflow detector. The overflow detector has a function of detecting a malfunction and issuing a warning.

In a highly advantageous embodiment of the present invention, the level in the titration vessel is monitored or sensed continuously, without relying on a discrete point measurement technique. As a result, it is possible to change the water and the reagent more accurately and continuously and to send them out, and it is also possible to automatically detect a malfunction. Such issues include, for example, insufficient reagents, low water pressure and inoperable valves. By using continuous titration vessel level sensing, the liquid can be sent to the titration vessel and measured using a simple, low cost valve. This is not accurate enough for titrants (eg, ± 0.001 milliliters), but is sufficient for conditioning reagents or buffers (eg, ± 0.1 milliliters).

To achieve continuous level measurement in a defined space containing a wide range of corrosive caustic solutions, detection of air pressure (ie, head pressure of static liquid against the top of a slowly bubbling immersed tube) ) Is performed in the titration vessel. Sensing tube is only 0.125 ”
No external head diameter is needed, thus requiring "headspace", ie, space for equipment just above the solution. The tube can be made of a semi-rigid or rigid material that is resistant to solution, such as Teflon or glass.

FIG. 1 is a schematic diagram of a coupling device 10 useful in the practice of the present invention. This coupling device applies a compressive load to the flared portion 13 of the tube 14 by means of a screw element 11. As shown in the drawing, the end face of the expanding portion 13 is brought into close contact with the elastic washer seal 15 to achieve the connection. It is common in today's industry to use such divergent tube connections. In known devices, in order to achieve a leak-free connection, the end of the tube (not shown) is expanded and the end face of a threaded nut (not shown) and a hard mating surface (not shown) Sandwich it between. Pipe with mating surface 13 and mating surface (not shown)
The presence of a chemically resistant elastomeric washer 15 between: 1) reduces the amount of torque required to form a seal; and 2) causes tube material creep or "cold flow". 3) to maintain the seal, and 3) to adjust the slightest defects in the mating surface of the tube to improve the connection. In performing this fit, a washer having an appropriate diameter and thickness is used to ensure that the washer is fully extended when forming the seal under compression, while not closing the fluid path through the center of the washer. It is important to use. In addition, by using a washer having an appropriate size, the washer can be easily aligned (arranged) at the time of installation. Notably, the elastomeric washer performs significantly better than conventional Teflon washers in that it is not susceptible to `` cold flow '' that either leaks or requires tightening. That's what it means.

FIG. 2 is a schematic diagram of an analyzer 20 illustrating a sample draw / purge technique useful in the practice of the present invention. The sample liquid supplied to the analyzer must, of course, represent the total volume of the sample in the tank. To accomplish this, the sample is sometimes withdrawn from a recirculation loop (not shown) formed by a pressure tube through which the sample normally flows. The analyzer accomplishes this and can draw samples from a stationary tank (not shown) several hundred feet away. In the illustrated embodiment of the present invention, the sample is supplied from three tanks (not shown) to the respective valves 22, 23, 24
Drawn through. The first purpose here is to obtain a representative sample. Another aim is to achieve this with the simplest or smallest device. One known solution to this problem is to attach a pump (not shown) to the tank and create an additional recirculation loop (not shown). This is due to the addition of relatively maintenance-intensive equipment, ie, pumps, and the plant (not shown).
It has the disadvantage of adding the danger of constantly recirculating the fluid throughout. Instead, the analyzer of the present invention uses a relatively simple eductor 26 to create a vacuum and draw the sample whenever needed beyond the sample detector 27. In addition, unused portions of the sample are drawn back to the tank by pressurized air or nitrogen supplied via valve 28 to purge the line and prepare for the next draw. In some aspects of the invention, a pump (not shown) may be used to create a vacuum instead of an eductor to avoid wasting water. This has the advantage of reducing the need for maintenance with only intermittent use. Also, in the case of a multi-tank, the required equipment is reduced in total. The preferred arrangement saves cost and equipment complexity by installing a single analyzer that draws samples from several tanks and utilizing a common vacuum system. The sample that reaches the vacuum system becomes waste. However, sample material that reaches the valve before the vacuum system is not waste.

The sampling method also has the advantage of a regular backflushing sample filter (not shown), which can be provided in the sample line. In conventional systems, the sample material flows through the filter in only one direction, causing premature deposits and clogging.

The sampling method of the present invention also has the advantage of ensuring that a fresh sample has arrived. The sample line is purged with gas after each analysis,
The sample detector 27 can be used to confirm a change from “no sample” to “with sample”. This change confirms sample utilization and presence and proper operation of the sampling system. By comparison, a recirculating sample system may only have an inert or non-representative sample therein. The mere detection of the presence of the sample in this case is insufficient to ensure correct analytical results.

FIG. 3 is a schematic view showing that a water or solvent rinse valve 29 can be added in addition to the purge gas valve 28 shown in FIG. Here, the rinse valve 29
Is provided for cleaning the system between sampling of incompatible liquids and for cleaning the purge gas valve itself. This function is important because if not, dried samples would accumulate in this and other valves, causing them to fail. There is also a need to place a rinse valve behind the purge gas valve. This is because without it, the purge gas valve is particularly affected by sample accumulation. This air / water (or gas / solvent) combination
It is particularly effective in that it cleans the device with minimal time and solvent consumption due to the high propulsion and flow caused by the gas. In the practice of the present invention, the gas produces rain which is propelled in the tube.

The three tank sample valves (22, 23, 24) shown in FIG. 2 are, in another embodiment, replaced by a single rotating valve (not shown) having multiple inlets and one outlet. be able to. This configuration minimizes "waste legs" and facilitates removal of old sample liquid. This is particularly advantageous when working with mutually incompatible samples. However, rotary valves can easily wear out and cause premature valve failure, especially when rotated when filled with sample.
This vulnerability is overcome by the gas / solvent rinse system described above (FIG. 3). This allows the rotation of the rotary valve to be limited to periods when the system is clean or empty.

The analyzer of the present invention uses a variable sample amount device. The device allows for a more versatile tool by allowing a wide range of samples to be concentrated, for example, by allowing a variety of different chemical reactions, each requiring only a single sample volume, to be performed sequentially. It can be. This sampling device is realized in the form of a syringe or burette and uses only the middle of the sample column in three parts. This technique prevents both the upper three-part air and the lower three-part sediment from becoming part of the sample analyzed. This feature is realized by this novel use of a variable sampling device.

The waste leaves the titration vessel extending along a vertical ascent path. This minimizes confinement of the sample mixture when compared to a horizontal or descending pass. The vertical path is
Keep air filled until emptied by waste eductor or pump. This is important because the trapped liquid can move or delay the end point of the titration.

In practicing the present invention, the flow of the electrolyte is intermittent and controlled. Electrochemical sensors such as pH sensors and ORP sensors require a reference cell and an electrical connection to the solution at zero potential. Many schemes have been tested for this, all of which have advantages and disadvantages. Gel-filled reference cell electrolytes have been used because of their low maintenance requirements. The electrolyte does not flow and does not require refilling, but is stagnant. However, the function of this cell electrolyte is impaired due to ion migration when the gel enters and exits and drift over a predetermined time,
The state becomes exhausted and the potential becomes a non-zero state. A known alternative is a slowly flowing reference electrolyte. In this known configuration, contaminants are released and a zero potential is maintained. A porous plug or stopper made of wood, ceramic or plastic is placed on the top to restrict the flow and thereby preserve the electrolyte. The disadvantage of this is that the pores eventually obstruct and restrict the flow of electrolyte and / or block the passage of current, reducing the stability and responsiveness of the electrode.

In the present invention, the device for restricting flow is a valve, not a porous plug. The valve is located upstream away from the sample. Thus, the valve cannot obstruct or prevent flow. The flow of the electrolyte becomes inactive during the measurement and the stability is improved. The electrolyte can then flow between one measurement and the next, thereby maintaining zero potential.

Another feature of the present invention is that the sample tube contacts the wall of the glass beaker. This breaks the droplets and allows the correct amount of sample to be dispensed. On the other hand, in order to minimize the mixing time, the top of the tube is directly directed to the liquid vortex. Furthermore,
To minimize signal fluctuations when the bubbles separate, the level sensing tube in the titration vessel should be
Cut at a 45 degree angle.

FIG. 4 illustrates an analyzer / controller system 40 constructed in accordance with the principles of the present invention.
FIG. 4 is a schematic diagram of the control method, and a control method will be described with reference to FIG. As shown in this figure, the analyzer 41 integrated with the manager 42 has a plurality of sample lines, specifically, H ₂
A sample line 44 from the O ₂ feed drum 48, a sample line 45 from the H ₂ O ₂ mixing station 49, and a sample line 46 from the H ₂ O ₂ distribution tank 50 are received.

Further, this figure shows a replenishment control unit 52 and a local control unit 53 (LCU5
3) and the level pressure transducer 55 are shown. Since the analyzer 41 and the manager 42 are combined, the automatic analysis of the distributed sample is performed under the control of the LCU 53. Analysis results include parameter history, replenishment printouts, system diagnostics,
The data is displayed on the display 57 together with the sensor calibration data, the operator alarm and the alarm. In the event of a malfunction, alarm 59 is activated, generating tower light and an audible signal.

This figure shows a replenishing device 60 including a precise syringe pump 62 for performing automatic replenishment based on the result of the above analysis. Refill controller 52 is used to receive multiple chemical dispenses from a common pump (not shown). Replenishment adjustments are made under software control according to a predetermined replenishment formula for adjustments based on the analysis of the H ₂ O ₂ replenishment feedstock drum 48.

The level monitoring of the distribution tank 50 monitors the level of this distribution tank,
Includes hardware and software that automatically adjusts replenishment rates as calculated from the analysis. In a particular embodiment of the present invention, the level device of the distribution tank, the NO ₂ to about 2
Teflon tube 64 containing ~ 10 psi. In this particular embodiment, the dispensing of the replenished liquid takes place via a global supply loop 66 shown schematically. The supply loop 66 may be pressurized.

FIG. 5 is a diagram schematically illustrating a fluid circuit interconnection between various components of the present invention. As shown, in practicing the present invention, a pair of chemical sensors 82 and 83 are housed in a reaction cell 80, which may be a glass beaker. In one embodiment of the present invention, chemical sensor 82 is an ion selective electrode ("ISE") and chemical sensor 83 is p-type.
H sensor or ORP electrode. The reaction cell 80 includes a mixer 85 disposed below the reaction cell 80.

[0097] Deionized water is fed into the reaction cell from a deionized water source 87 via a valve 88. Valve 88 is an electrically operated two-way valve. Precise amounts of sample solution and predetermined reagents are delivered by respective syringe assemblies 90, 91, 92 and 93. In this embodiment of the present invention, the syringe assembly, the sample, NaOH, is devoted to the _{Ag 2 NO 3, Na 2 S} 2 O 3. These syringe assemblies are controlled by stepping motors (not shown) controlled by the electronics shown in FIG. 7 via respective electrical valves 95-98. In this embodiment, nitrogen gas is used for purging the syringe assemblies 90, 91, 92, and 93, and the rinsing can be controlled by the control panel 100. Regarding the nitrogen cleaning process related to the operation of the control panel 100,
This will be described later with reference to FIG.

The waste cell 112 (FIG. 6) is connected to the reaction cell 80 via the electric valve 110.
From the waste. FIG. 6 is a schematic diagram of the interconnection between the various components of the present invention. The components described above are denoted by the same reference numerals. As shown, the electric valve 110 is connected to a waste pump 112.

The liquid sample from the sampling chamber 155 is supplied via lines 116 and 117. Here, a proximity sensor 118 is arranged on the line 117 and sends a signal indicating that the sample has arrived to a control device (not shown). The sample is drawn into the syringe assembly 90 via a three-way electrical valve 95.

FIG. 6 further shows that a plurality of sample sources 121 to 125 have air valves 131 to 1 respectively.
A sampling chamber 120 connected via 35 is shown. Each air valve is connected to an air source 140 via electric valves 141-145, respectively.

FIGS. 5 and 6 show that deionized water from deionized water source 87 is directed to the top of cell chamber 120 via electrical valves 150 and 152. Cell room 1
The bottom of 20 is connected to a common line 155 to which sample sources 121 to 125 are connected via air valves 131 to 135, respectively. The common line 155 is connected to the waste valve 160. In addition, a glove sample source 161 is shown in these figures. The grab sample source 161 is connected to the common line 15 via an electric valve 163.
5 and the common line 155 is connected to the bottom of the cell chamber 120 as described above. FIG. 5 shows that in this particular embodiment, the club sample 161 is withdrawn from the trough 165.

FIG. 6 shows that the KCl electrolyte source 170 is located in the reagent compartment 171. The KCl electrolyte is supplied to the contents of the reaction cell 80 via the electric valve 174. Similarly, a KI source 176 and a H ₂ SO ₄ source 177 located in this reagent compartment
Are fed into the reaction cell via electric valves 178 and 179, respectively. This reagent compartment holds several reagent sources, as shown, which are each supplied to a syringe assembly 90, 91, 92, 93. These reagents have already been described. The electric valves 95-98 are three-way valves, each of which can be controlled such that a corresponding syringe assembly takes in each reagent and delivers precisely measured reagents to the reaction cell.

FIG. 7 is a schematic diagram of a nitrogen gas circuit, and further includes a stepping motor control board 18.
0 and an electronic system for generating the electrode signals. Referring to FIGS. 5 and 7, a nitrogen source 184 supplies nitrogen to pressure regulators 182 and 183. Each pressure regulator is connected to a corresponding pressure gauge 185 and 186, respectively. Pressure regulated nitrogen is directed from one pressure regulator 183 via line 188 to a T coupler 190 located between electrical valves 150 and 152. This nitrogen is used to purge the sampling chamber 120. The other pressure regulating nitrogen is led to the reaction cell 80 via the valve 192 and the line 193.

FIG. 7 shows three more signal state amplifiers 200, 201 and 202. These amplifiers are electrically connected to the ISE, ORP, and pH electrodes, respectively. In one embodiment of the present invention, signal condition amplifier 200 has a rated input voltage of ± 2000 mV, signal condition amplifier 201 has a rated input voltage of ± 1000 mV, signal condition amplifier 2.
O2 has a rated input voltage of ± 420 mV, and is insulated and grounded. A stepping motor (not shown) for controlling the syringe assembly is controlled by a stepping motor control board 180. In this embodiment of the invention, stepper motor control board 180 is capable of controlling four stepper motors.

While the invention has been described with reference to particular embodiments and applications, those skilled in the art, in light of this teaching, will appreciate that additional embodiments can be made without departing from or departing from the scope of the appended claims. Can be created. Therefore, the description in the specification and the drawings is for facilitating the understanding of the present invention, and does not limit the scope of the present invention.

[Brief description of the drawings]

FIG. 1 is a plan view of a coupling device useful in practicing the present invention.

FIG. 2 is a schematic diagram of an analyzer device for extracting a sample from a plurality of chemical tanks.

FIG. 3 is a schematic diagram of an apparatus in which a rinsing solvent is combined with the purge gas apparatus of FIG. 2;

FIG. 4 is a schematic diagram showing an embodiment of the analyzer / control device of the present invention, showing a control method.

FIG. 5 is a schematic diagram illustrating fluid flow interconnections between various components of the present invention on a first side of a device panel.

FIG. 6 is a schematic diagram illustrating the interconnections between various electrical components of the present invention.

FIG. 7 is a schematic diagram showing a nitrogen gas circuit and a stepping motor control board 180 on a second surface of the apparatus panel shown in FIG. 5;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Connection apparatus, 11 ... Screw element, 13 ... Expansion part, 14 ... Tube, 15 ... Washer seal, 20 ... Analyzer, 22,23,24,28 ... Valve, 26 ... Eductor, 27 ... Sample detector, 28 ... purge gas valve, 29 ... rinse valve, 40 ... analyzer / controller system, 41 ... analyzer, 42 ... manager, 44, 45,
46: sample line, 48: H ₂ O ₂ feed drum, 49: H ₂ O ₂ mixing station, 50: H ₂ O ₂ distribution tank, 52: replenishment control device, 53: local control unit, 55: level pressure conversion 57, display, 59, alarm, 60, refill, 62, syringe pump, 64, tube, 66, global supply loop, 80
... Reaction cell, 82, 83 ... Chemical sensor, 85 ... Mixer, 87 ... Deionized water source, 8
8: Valve, 90, 91, 92, 93: Syringe assembly, 95 to 98: Electric valve, 100: Control panel, 112: Waste pump, 116, 11
7 ... line, 118 ... proximity sensor, 121-125 ... sample source, 131-135 ...
Air valve, 120: sampling chamber, 140: air source, 141 to 145: electric valve, 161: grab sample source, 165: trough, 170: KCl electrolyte source, 17
1 ... reagent compartment, 174, 178, 179 ... electric valve, 176 ... KI source, 177
... H ₂ SO _4, 180 ... stepping motor control board, 182, 183 ... pressure regulator, 184 ... nitrogen source, 185, 186 ... pressure gauge, 188 ... Line, 190 ... T
Coupler, 192 ... valve, 193 ... line, 200, 201, 202 ... signal state amplifier.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 21/304 622 H01L 21/304 622S (81) Designated country EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE), OA (BF, BJ, CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP (GH, GM, KE, LS, MW, SD, SL, SZ, UG, ZW), EA (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, CA, CH, CN, CU, CZ, DE, DK, E , ES, FI, GB, GD, GE, GH, GM, HR, HU, ID, IL, IN, IS, JP, KE, KG, KP, KR, KZ, LC, LK, LR, LS, LT, LU, LV, MD, MG, MK, MN, MW, MX, NO, NZ, PL, PT, RO, RU, SD, SE, SG, SI, SK, SL, TJ, TM, TR, TT, UA , UG, US, UZ, VN, YU, ZW F term (reference) 2G042 AA01 CB03 GA02 HA02 HA03 HA07 HA10 4G068 AA02 AB11 AB17 AB30 AD01 AD21 AD24 AD36 AD39 AF01 AF09 AF28 AF29 AF31 4K057 WA19 WD10 WE25 WF10 WL03 AWM WM02 BB03 BB16 DD12 FF15 GG01

Claims (77)

[Claims] 1. A chemical control system for a chemical solution containing a predetermined chemical component, comprising: an analyzer for determining a proportion of the predetermined chemical component in the chemical solution to be delivered; A precision analyzer sample delivery device for delivering a sample to the analyzer, a control device for receiving information about the analyzer's determination of one of the predetermined chemical components in the chemical solution to be delivered, And a replenishing device for feeding a controlled amount of the predetermined chemical component. 2. The chemical control system according to claim 1, wherein said analyzer is a titrator system. 3. The analyzer according to claim 1, further comprising: a reaction cell for receiving a sample of the chemical solution from the precision analyzer sample feeder; and selectively measuring a predetermined characteristic of the chemical solution and a progress of the reaction with the chemical solution. The chemical control system according to claim 1, further comprising: 4. The chemical control system according to claim 3, wherein said reaction cell is a glass beaker. 5. The chemical control system according to claim 3, wherein said sensor is a pH electrode. 6. The chemical control system according to claim 3, wherein said sensor is an ORP electrode. 7. The chemical control system according to claim 3, wherein said sensor is an ion-selective electrode. 8. The chemical control system according to claim 3, wherein said sensor is a turbidity sensor. 9. The chemical control system of claim 1, wherein said chemical solution is a slurry, and wherein one of said predetermined chemical components in said slurry is H ₂ O ₂ . 10. The chemical control system according to claim 1, further comprising a global loop for distributing said chemical solution. 11. The chemical control system according to claim 1, wherein said control device comprises a display device for displaying information according to the decision made by said analyzer. 12. The chemical control system according to claim 11, wherein said display device displays information according to a plurality of predetermined parameters of said chemical control system. 13. The chemical control system according to claim 11, wherein said display device displays information according to a diagnosis condition of said chemical control system. 14. The chemical control system according to claim 11, wherein said display device displays information corresponding to a history of a refilling operation by said refilling device. 15. The system according to claim 11, wherein the display device displays information corresponding to a history of the failure of the system.
Chemical control system. 16. The chemical control system according to claim 11, further comprising a chemical sensor, wherein said display device displays information corresponding to calibration of said chemical sensor. 17. The chemical control system according to claim 11, further comprising a chemical tank, wherein said display device displays information according to an amount of said chemical solution in said chemical tank. 18. The chemical control system according to claim 17, further comprising a liquid level monitor connected between said chemical tank and said controller. 19. The liquid level monitoring device comprises a pressure monitor system for measuring the pressure of a monitor gas sent to the chemical tank via a pressure regulator and an orifice, and extends so as to be immersed in the tank. 19. The chemical control system of claim 18, wherein monitoring is performed in a flow area past the orifice in an inert tube. 20. The chemical control system of claim 19, wherein the pressure of the monitor gas sent to said liquid level monitor prior to said orifice is between 1 and 15 psi. 21. The chemical control system according to claim 20, wherein the pressure of the monitor gas sent to the liquid level monitor is 2 to 10 psi. 22. The chemical control system of claim 1, wherein said precision analyzer sample feeder comprises an eductor for drawing a sample into said analyzer. 23. The chemical control system according to claim 1, further comprising a purge system for purifying said analyzer. 24. The chemical control system of claim 23, wherein said purge system comprises a gas purge valve for controlling a pressurized purge gas for purifying said analyzer. 25. The chemical control system of claim 24, wherein said purge system comprises a rinse solvent purge valve for controlling a rinse solvent for purifying said analyzer. 26. The chemical control system of claim 25, wherein the actuation of the rinse solvent purge valve further purges the analyzer and analyzer tubing associated with the gas purge valve. 27. A chemical control system for a chemical solution containing a predetermined chemical component, comprising: a precision analyzer sample delivery device for delivering a precision sample of the chemical solution; and a reaction cell for receiving the precision sample of the chemical solution. A precision analyzer reagent delivery device for delivering a precise amount of a predetermined reagent to the reaction cell; a sensor for measuring a property of the chemical solution; and information relating to the property of the chemical solution measured by the sensor. And a replenishing device for receiving a controlled amount of the predetermined chemical component in response to the control device. 28. The chemical control system of claim 27, further comprising a second sensor for detecting the effectiveness of said solution. 29. The chemical control system according to claim 28, wherein said second sensor is a proximity sensor. 30. The precision analyzer sample delivery device includes a syringe.
7. Chemical control system. 31. The chemical control system of claim 30, comprising a controllable drive for driving said syringe. 32. The chemical control system of claim 31, wherein said controllable drive comprises a stepper motor drive. 33. The chemical control system of claim 27, wherein said replenishing device is configured to deliver said controlled amount of said predetermined chemical component to a storage tank for said chemical solution. 34. The chemical control system according to claim 27, further comprising a purifying device for purifying the reaction cell by removing a sample before the chemical solution. 35. The chemical control system of claim 34, wherein said purifier includes a purge gas. 36. The chemical control system of claim 35, wherein said purifier includes a rinsing solvent. 37. The chemical control system according to claim 34, wherein said purifying device includes a syringe circulating device for circulating a sample syringe until a previous sample is removed. 38. A method for analyzing a chemical solution having a first chemical composition in a tank, comprising: sending a sample of the chemical solution having the first chemical composition to an analysis cell; and sending the sample to the analysis cell. Performing a titration analysis on the obtained chemical solution having the first chemical composition, comprising: controlling a syringe so as to feed the titrant into the chemical solution; and performing the titration analysis while performing the titration analysis. A method comprising: titrating analysis comprising monitoring a defined chemical property; determining an endpoint of the titration analysis; and performing a purification procedure. 39. The method of claim 38, wherein said delivering step comprises the step of delivering a predetermined sample amount of a chemical solution having said first chemical composition to said analytical cell. 40. The method of claim 39, wherein the step of delivering a predetermined sample amount of the chemical solution having the first chemical composition to the analysis cell includes performing a cycle through the sample syringe. 41. The method of claim 38, wherein said feeding step includes an initial step of adjusting a rate at which said step of performing a titration analysis is performed in inverse proportion to a rate of change of a monitoring signal. 42. The method of claim 38, wherein the feeding step further comprises a final step in which the speed of the feeding is constant and slowed as the end point of the titration analysis approaches. 43. The method of claim 38, wherein said pumping step comprises removing all liquid corresponding to a previous sample from the sample loop. 44. The method as recited in claim 44, wherein the delivering step includes using a continuous pneumatic sensor to detect and confirm that all reagents, including a sample of the chemical solution having the first chemical composition, have been delivered to the analysis cell. 39. The method of claim 38, wherein: 45. The method according to claim 44, wherein the feeding step includes a step of measuring a timing of feeding each chemical solution to the analysis cell in order to monitor normality of reagent supply and apparatus operation. 46. The method of claim 38, wherein performing the titration analysis comprises delivering a conditioning reagent. 47. The method of claim 46, wherein delivering the conditioning reagent comprises controlling a gravity feeder. 48. The method of claim 46, wherein delivering the conditioning reagent comprises controlling a pump. 49. The method of claim 38, wherein controlling a syringe to carry a titrant comprises controlling a stepper motor coupled to the syringe. 50. The method of claim 38, wherein analyzing the predetermined chemical property of the chemical solution comprises reading the predetermined chemical property as an analog value. 51. The method of claim 50, wherein the steps of analyzing predetermined chemical properties of the chemical solution and determining the end point of each titration analysis are repeated. 52. The steps of analyzing a predetermined property of the chemical solution and determining an end point for each titration analysis are repeated until reproducibility of the results of the titration analysis is established within predetermined parameters. 52. The method of claim 51, wherein: 53. The method of claim 52, wherein the steps of analyzing a predetermined property of the chemical solution and determining an end point for each titration analysis are repeated about 2 to 9 times. 54. The step of performing the cleaning procedure includes purging gas backward through a filter through which the chemical solution having the first chemical composition sent to the analysis cell passes while performing the step of sending the sample. 39. The method of claim 38, comprising pushing forward. 55. The method of claim 54, further comprising the step of generating an error alert when the gas pressure is determined to exceed a predetermined pressure during the step of pushing the gas purge. 56. A step of injecting rinsing water with the purge gas through a filter through which the chemical solution having the first chemical composition sent to the analysis cell flows while performing the sample sending step. 55. The method of claim 54, wherein 57. The method of claim 56, wherein said rinsing water is a high speed and low volume spray. 58. The method of claim 56, further comprising the step of agitating the titrator to a maximum agitation rate that does not cause whipping to optimize titration and agitation. 59. The method of claim 56, further comprising the step of circulating through the sample syringe until the sample syringe is clean. 60. The method of claim 38, comprising calibrating the pH electrode prior to performing said performing a titration analysis. 61. The step of calibrating the pH electrode further comprises the steps of: performing a first pH reading on the pH electrode using a first pH buffer; and performing the calibration on the pH electrode using a second pH buffer. 61. The method of claim 60, comprising: performing a second pH reading at; and determining a slope value and an offset value for the pH electrode. 62. The method of claim 38, wherein providing an ORP electrode and performing said titration analysis comprises performing a differential titration analysis. 63. The method of claim 62, comprising determining the sensitivity of said ORP electrode prior to performing said differential titration analysis. 64. The step of determining the end point of the titration analysis comprises the step of determining the turbidity end point of the titration analysis, and further comprising the step of determining the turbidity end point using a turbidity sensor. 38 methods. 65. The step of performing the titration analysis on the chemical solution having the first chemical composition sent to the analysis cell includes the step of titrating a solution having an unknown cyanide concentration. Clause 64. The method of clause 64. 66. The method of claim 65, wherein the step of titrating the solution of unknown cyanide concentration uses silver ions. 67. Determining the turbidity end point of the titration using the turbidity sensor comprises determining a change in the rate of change in turbidity of the chemical solution and titrating until the rate of change drops to near zero. 65. The method of claim 64, comprising: 68. A method for analyzing a chemical solution having a first chemical composition in a tank, comprising: sending a sample of the chemical solution having the first chemical composition to an analysis cell; and sending the sample to the analysis cell. Performing ion selective analysis on the chemical solution having the first chemical composition, wherein the chemical solution having the first chemical composition sent to the analysis cell includes a standard solution having a known concentration of an electrolyte. Sending a predetermined amount a plurality of times, and after each feeding of the predetermined amount of the standard solution, according to a predetermined chemical property of the chemical solution having the first chemical composition sent to the analysis cell. An ion selective analysis step including a step of measuring a potential of an ion selective electrode; and a step of determining an amount of an electrolyte in a chemical solution having the first chemical composition sent to the analysis cell, Method characterized by comprising a step comprising extrapolating the values of a plurality of electrode potential at the point set in advance in the electrolyte concentration. 69. The method of claim 68, wherein the step of delivering the predetermined amount of the standard solution a plurality of times comprises delivering the predetermined amount of the standard solution approximately two to six times. 70. The step of delivering a predetermined amount of a standard solution having a known concentration of an electrolyte a plurality of times, wherein determining the amount of the standard solution having a known concentration of the electrolyte, thereby determining the predetermined amount of the standard solution. Measuring the potential of the ion selective electrode according to a predetermined chemical property of the chemical solution having the first chemical composition sent to the cell for analysis after each feeding of 69. The method of claim 68, comprising including the difference between the values being approximately 3mV to 40mV. 71. The method of claim 70, wherein the difference between the sequentially measured potential values is approximately 5 mV to 30 mV. 72. The method of claim 71, wherein the difference between the sequentially measured potential values is approximately 20 mV. 73. The method of claim 68, further comprising reducing the speed at which the step of delivering the predetermined amount of the standard solution multiple times is performed. 74. The method of claim 68, wherein the extrapolating step comprises extrapolating the plurality of measured electrode potential values to a zero point of the electrolyte concentration. 75. In the step of feeding a predetermined amount of a standard solution having an electrolyte of a known concentration a plurality of times, the concentration of the electrolyte in the standard solution has the first chemical composition sent to the analysis cell. 69. The method of claim 68, wherein the concentration of the electrolyte in the chemical solution is greater than the concentration of the electrolyte in the chemical solution, thereby reducing dilution of the chemical solution having the first chemical composition. 76. A fitting for connecting tubes, comprising: a diverging end of a tube member having an annular surface; a pressure washer coaxially joined to said diverging end; A pressure fitting part having a screw part for pressing the pressure washer so as to be pressed in the axial direction. 77. The fixture according to claim 76, wherein said pressure washer is formed of an elastic body.