TWI454872B - An etching solution mixing device and an etching solution concentration measuring device - Google Patents

Description

Etching solution blending device and etching solution concentration measuring device

The present invention relates to a semiconductor film manufacturing process or a flat panel display manufacturing process (liquid crystal substrate manufacturing engineering, organic EL display manufacturing engineering, etc.) connected to an aluminum film (for example, a film of aluminum or aluminum alloy, molybdenum or molybdenum alloy) An etching solution blending device for an etching device for a film and a second film of aluminum or aluminum alloy; hereinafter referred to as an aluminum film.

An etching process for an aluminum film such as a liquid crystal substrate manufacturing process, a mixed aqueous solution of nitric acid and phosphoric acid as an etching solution, a mixed aqueous solution of nitric acid and phosphoric acid and acetic acid, a mixed aqueous solution of nitric acid and phosphoric acid and malonic acid, and the like as an acid component. The mixed acid aqueous solution is used by spraying or by immersion. Mostly, a mixed aqueous solution of nitric acid, phosphoric acid and acetic acid is used. For example, an aqueous solution having a phosphoric acid concentration of 70.0%, an acetic acid concentration of 10.0%, a nitric acid concentration of 4.0%, and a water concentration of 16.0% may be mentioned.

The etching solution for the aluminum film for the liquid crystal substrate manufacturing process, in order to obtain the highest resolution with the etching process, the pattern is clear, the specific taper angle, the stability and the high production yield, the composition and concentration must be strictly controlled. . In particular, with the recent high definition of patterning, the miniaturization of the pattern width has been demanded. Along with this, the improvement of the blending precision of the etching liquid concentration is strongly demanded.

In addition, as the amount of the etching liquid used increases, the size of the liquid crystal display increases, the size of the glass substrate increases due to the multi-faceted single-piece substrate, mass production, and the like, so that a large amount of etching liquid becomes necessary. Furthermore, with the low price competition of liquid crystal displays in the world, the cost of reducing the etching liquid is also strongly demanded.

In order to cope with such a problem, for example, a chemical liquid monitoring device that continuously switches a plurality of etching grooves in order to continuously measure the concentration or temperature of the chemical solution in one measurement system has been proposed (for example, see Patent Document 1).

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2003-086565

However, in the past, the etching liquid was used after the blending (recipe) and the concentration were adjusted to the target value in a manufacturing plant such as a liquid crystal display, not only in terms of equipment and running costs, but also from the viewpoints of techniques such as concentration measurement. It is extremely difficult. It is necessary to measure the concentration of each component in order to verify whether or not it is a specific composition and concentration in order to mix the nitric acid stock solution, the phosphoric acid stock solution, the acetic acid stock solution, and the pure water etching solution.

However, it is impossible to accurately measure the concentration of nitric acid, phosphoric acid, and acetic acid in the etching solution either online or offline. It is impossible to immediately measure the acid concentration after blending.

In the past, it has not been conventionally known to measure the application of such three kinds of mixed acids. The etchant manufacturer, for example, samples the etched liquid after one adjustment, measures the acid concentration by an off-line ion chromatography analyzer, and replenishes the under-adjusted stock solution for secondary blending. One part is a device for batch concentration adjustment by intermittent measurement by non-aqueous and titration methods, but it has a complicated device, and it is necessary to use a titration reagent and waste liquid, and because it is intermittently There are many problems such as poor control and so on.

In other words, in a manufacturing plant such as a liquid crystal display (hereinafter referred to as "use side"), it is necessary to use an etching liquid which has been adjusted in composition and concentration by an etchant manufacturer (hereinafter referred to as "supply side").

In this case, a method in which an etchant prepared by mixing a nitric acid raw solution, a phosphoric acid stock solution, an acetic acid stock solution, and pure water adjusted to a specific concentration on a supply side to a specific composition and concentration is filled in a container and then supplied to the use side is used.

The etching liquid prepared on the supply side needs to be in a period corresponding to transportation and storage until it is used on the use side, and there is a problem that the etching liquid is deteriorated during this period. Further, since acetic acid in the etching liquid is volatile, there is a problem that the concentration of acetic acid is lowered, and nitric acid is volatilized into NOx gas, which causes a problem that the concentration of nitric acid is lowered.

Further, the etchant blending device of the continuous blending method has not been seen not only on the use side but also on the supply side. This is because there is no concentration measuring device that continuously measures the component concentration of the etching liquid. These problems can also be used as a major reason why the blending of the etching liquid is not performed in a manufacturing plant (use side) such as a liquid crystal display.

Here, the present invention has been made in view of the above circumstances, and an object of the present invention is to provide an etching liquid which can be accurately and quickly adjusted from a etching stock solution to a desired concentration on the use side, and which can accurately manage the composition of the etched liquid which is blended. And a concentration of etching solution blending device.

In order to achieve the above object, the inventors of the present invention first confirmed the correlation between the nitric acid concentration of the etching solution in the blending tank and the conductivity of the diluent which diluted the etching solution to a specific magnification with pure water as shown in FIG. . Further, it was confirmed by experiments that the nitric acid concentration of the etching solution of the blending tank was correlated with the absorbance as shown in FIG. Further, it was confirmed by experiments that the water concentration of the etching liquid in the blending tank was correlated with the absorbance as shown in FIG. Further, it was confirmed by experiments that the phosphoric acid concentration of the etching solution was correlated with the absorbance as shown in FIG. Further, the phosphoric acid concentration of the etching solution was confirmed by experiments as shown in Fig. 13 in relation to its density.

In the present invention, the nitric acid concentration is adjusted and controlled by measuring the conductivity of the diluted aqueous solution, and the nitric acid concentration is adjusted and controlled by the absorbance measurement, and the water concentration is adjusted and controlled by the absorbance measurement, and the absorbance is adjusted and controlled. In addition, since the phosphoric acid concentration is adjusted and controlled by the density measurement, the concentration of the three components of the nitric acid concentration, the water concentration, and the phosphoric acid concentration is comprehensively adjusted and controlled.

Further, the present invention is intended to improve the conductivity value of the conductivity meter based on the correlation calculation, and to measure the conductivity of the diluent after diluting the etching liquid in the mixing tank with pure water (or the illuminating meter of the etching solution) The absorbance value) and the absorbance value of the absorbance photometer that detects the water concentration of the etching solution and the absorbance value (or the density value of the densitometer) of the absorbance photometer that detects the phosphoric acid concentration of the etching solution are performed by a multi-component algorithm ( The double regression analysis method and the multivariate analysis method are used to adjust and control the component concentration of the etching liquid which is more correct. In this case, the acetic acid concentration can be calculated by subtracting the nitric acid concentration, the water concentration, and the phosphoric acid concentration from 100%.

In other words, in order to achieve the above object, the etching solution mixing device of the present invention includes a mixing tank for arranging an etching solution for an aluminum film, a pipe connected to the mixing groove, and the like, as shown in Figs. 1 and 5 a pump for feeding the etchant or the liquid used for the immersion of the etchant; an etchant blending device connected to the etching device by the pipeline, characterized in that: pure water is detected by a conductivity meter a nitric acid stock solution obtained by diluting a nitric acid concentration of the etching liquid obtained by diluting a conductivity of a diluent of the etching liquid in the mixing tank or a nitric acid concentration of the etching liquid obtained by detecting an absorbance of the etching liquid by an absorption photometer At least one of a mixed acid solution or pure water, a nitric acid concentration detecting/liquid replenishing means for replenishing the mixing tank, and a monoacid stock solution and a mixed acid according to a water concentration of the etching liquid obtained by detecting the etching liquid by an absorption photometer At least one of a raw liquid or pure water, a water concentration detecting/liquid replenishing means for replenishing the mixing tank, and detecting the suction of the etching liquid by an absorption photometer Phosphoric acid concentration of the etching liquid obtained by luminosity or phosphoric acid concentration of the etching liquid obtained by detecting the density of the etching liquid by density, and at least one of a monoacid stock solution, a mixed acid stock solution or pure water is supplied to the blending tank Concentration detection / liquid replenishment means.

In addition, as shown in FIG. 2 and FIG. 6, the etching liquid mixing device of the present invention includes a mixing tank for arranging an etching solution for an aluminum film, a pipe connected to the mixing tank, and the etching liquid sent to the pipe. Or a pump for the liquid of the aforementioned etching liquid; connected to the etching device by the aforementioned pipe An etching solution mixing device characterized by comprising: a conductivity meter for detecting a conductivity of a diluent for diluting an etching liquid in the mixing tank with pure water; or an absorption photometer for detecting a nitric acid concentration of the etching solution, and detecting An absorptiometer for extracting a water concentration of the etching solution, an absorbance photometer or a densitometer for detecting a phosphoric acid concentration of the etching solution, and a conductivity value of the conductivity meter for detecting a nitric acid concentration or detecting the nitric acid concentration The absorbance value of the absorptiometer, and the absorbance value of the absorbance photometer that detects the water concentration, the absorbance value of the spectrophotometer that detects the phosphoric acid concentration, or the density value of the densitometer that detects the phosphoric acid concentration, etc. a component calculation algorithm (regression analysis method, multivariate analysis method) for calculating a component concentration calculation method of a component concentration of the etching liquid, and a liquid supply for supplying at least one of a monoacid stock solution, a mixed acid stock solution, and pure water to the blending tank means.

Further, the etching liquid mixing device according to the present invention is characterized in that the etching liquid further contains an aqueous solution of phosphoric acid or nitric acid, and the etching liquid further contains an aqueous solution of at least one of an organic acid, hydrochloric acid, sulfuric acid, and perchloric acid. The acid-based acetic acid and malonic acid, and the etching liquid blending device are continuously blended.

As described above, according to the etching liquid blending device of the present invention, the following effects can be exhibited.

(1) An etching liquid blending device of an aluminum film which is extremely difficult in the past can be realized on the use side of a semiconductor manufacturing factory or a flat panel display manufacturing factory.

(2) The nitric acid concentration, the water concentration, the phosphoric acid concentration, and the acetic acid concentration of the etching solution can be measured continuously and continuously, and can be continuously adjusted to a specific concentration with a high degree of accuracy.

(3) Even if the acetic acid in the etching solution is volatile and the acetic acid concentration is lowered, and the nitric acid is volatilized into NOx gas and the concentration of nitric acid is lowered, the concentration is continuously measured, so that the concentration is automatically adjusted to the target value. .

(4) Since the concentration of the etched liquid to be tempered can be accurately maintained, the control of the high-definition size of the aluminum film can be made constant, and the control of the taper angle of the aluminum film is also fixed to produce the product. The yield has increased significantly.

(5) The etchant can be blended and the concentration can be verified on the use side, so that a large amount of etching liquid can be produced, the etching device can be directly supplied to the pipeline, and the cost can be reduced.

Hereinafter, a suitable embodiment of the present invention will be described in detail with reference to the drawings. However, the shapes of the constituent devices described in the embodiments, the relative arrangement thereof, and the like are not intended to limit the scope of the invention to the drawings, and the drawings are merely illustrative examples.

Fig. 1 is a system diagram showing a device according to a first embodiment of the present invention. The reference numerals in the figures are the machines and parts that constitute the etching solution blending device. That is, the etching liquid mixing device is a mixing tank 1 for adjusting the etching liquid, a liquid level meter 2, a circulation pump 11 for purifying and stirring the etching liquid, and also for supplying the liquid to the etching device, and piping 12. The filter 13 for removing fine particles in the etching liquid, the air valve 14 for circulating agitation, the phosphate raw material supply tank 20, the flow rate adjusting valve 24 for supplying the phosphate raw liquid, the acetic acid raw liquid supply tank 21, and the acetic acid raw liquid supply The flow rate adjusting valve 25, the nitric acid raw material supply tank 22, the flow rate adjusting valve 26 for supplying the raw nitric acid liquid, the flow rate adjusting valve 27 for supplying pure water, the air valve 29 for supplying the liquid to the point of use (POU), and the connection The piping of each machine, the N ₂ gas piping 23, piping of pure water, etc. are comprised.

According to the present invention, the apparatus attached to the etching liquid mixing device is a sampling pump 3, a dilution pump 38, a pure water pump 39, a conductivity meter 15 that detects a nitric acid concentration, and an absorptiometer 16 that detects a water concentration, and detects An absorbance photometer of phosphoric acid concentration, an electric instrument or an air meter.

The supply liquid is a phosphate stock solution, an acetic acid stock solution, a nitric acid stock solution, a mixed acid stock solution, and pure water, but not all of them are required, and depending on the composition of the etching liquid, equipment conditions, operating conditions, and conditions for obtaining the supply liquid, etc. The selection of the optimum supply liquid and supply device is the same for FIGS. 2 to 8.

As a blending method, it is preferable to use a continuous blending method, but it may also be a batch blending method. In the case of continuous blending, use one-time blending, using pure water, phosphoric acid stock solution, acetic acid stock solution, and nitric acid stock solution, first prepare a once-adjusted acetic acid-rich blending solution that increases the concentration of acetic acid, and then supplement it with pure water, phosphoric acid stock solution, and nitric acid stock solution. Micro adjustment to a specific concentration is also possible. In the case of the batch blending method, the order of mixing the raw liquids is preferably pure water, a phosphoric acid stock solution, an acetic acid stock solution, or a nitric acid stock solution.

The phosphate raw material supply tank 20 storing the phosphoric acid stock solution is pressurized to 0.1 to 0.2 MPa with N ₂ gas from the pipe 23, and is pressurized by the opening of the phosphoric acid raw material flow rate adjusting valve 24. The acetic acid stock solution supply tank 21 in which the acetic acid stock solution is stored is pressurized to 0.1 to 0.2 MPa with N ₂ gas from the piping 23, and is pressurized by the opening of the acetic acid raw liquid flow rate adjusting valve 25. The nitric acid raw material supply tank 22 that stores the nitric acid raw liquid is pressurized to 0.1 to 0.2 MPa by the N ₂ gas from the pipe 23, and is pressurized by the opening of the nitric acid raw material flow rate adjusting valve 26. The pure water communicates with the branch pipe from the existing pipe, and is supplied by the opening of the pure water flow regulating valve 27. These supply liquids are automatically adjusted by individual valves and supplied to the mixing tank 1.

Further, a portion of the etching liquid sampled by the mixing tank 1 by the sampling pump 3 of the line 18 is separated by the dilution pump 38 of the line 34, and is mixed with the pure water of the pure water pump 39 from the line 35. The mixture is mixed and stirred by the line 36 to be diluted to a specific ratio, and then the conductivity of the diluent is continuously measured by the conductivity meter 15 which detects the concentration of the nitric acid, and the already measured diluent is discharged from the line 37.

The etching solution is preferably diluted in a continuous manner according to the dilution method of the pure water, and a batch dilution method in which the etching solution and the pure water are supported by the stirring tank may be used.

The nitric acid concentration of the diluent can be measured by measuring the conductivity of the diluent, but since it is diluted to a specific ratio (for example, 10 times), the nitric acid concentration of the etching solution before dilution can be measured. Further, if the conductivity of the etching liquid before dilution is measured to measure the nitric acid concentration, it is difficult because the phosphoric acid concentration or the acetic acid concentration greatly affects the conductivity.

Fig. 2 is a system diagram showing a second embodiment of the present invention. This embodiment is added to improve the measurement accuracy of the first embodiment. Multi-component calculator 33. The other configuration is the same as that in the case of Fig. 1 .

Fig. 3 is a system diagram showing a third embodiment of the present invention. In the present embodiment, the sampling pump 3 is sampled by the mixing tank 1, the absorptiometer 19 for detecting the nitric acid concentration set offline, the absorptiometer 16 for detecting the water concentration, and the absorptiometer 17 for detecting the phosphoric acid concentration, from the tube. The path 18 is introduced into the sample solution to continuously measure the absorbance, and the measured liquid is returned to the mixing tank 1. The other configuration is the same as that in the case of Fig. 1 .

Fig. 4 is a system diagram showing the apparatus of the fourth embodiment of the present invention. In the present embodiment, the multi-component calculator 33 is added in order to improve the measurement accuracy of the third embodiment. The other configurations are the same as those in the case of Figs. 1 and 3.

Fig. 5 is a system diagram showing the apparatus of the fifth embodiment of the present invention. In this embodiment, in order to perform batch blending, a load cell 4 is attached to the blending tank 1 of FIG. 1 instead of the liquid level altimeter 2, and the weight of the blending liquid of the blending tank 1 is accurately measured, according to one blending The concentration and the concentration measurement value are used for concentration adjustment. The other configuration is the same as that in the case of Fig. 1 .

Fig. 6 is a system diagram showing the apparatus of the sixth embodiment of the present invention. In this embodiment, in order to perform batch blending, a load cell 4 is attached to the blending tank 1 of FIG. 2 instead of the liquid level altimeter 2, and the weight of the blending liquid of the blending tank 1 is accurately measured, and the concentration is from the concentration. The measured value is used to calculate the supplementary weight and to control the supplementary weight. The other configuration is the same as that in the case of Fig. 2 .

Fig. 7 is a system diagram showing the apparatus of the seventh embodiment of the present invention. In this embodiment, in order to perform batch blending, a load cell 4 is attached to the blending tank 1 of FIG. 3 instead of the liquid level altimeter 2, and the weight of the blending liquid of the blending tank 1 is accurately measured, according to one round of blending. The concentration and the concentration measurement value are used for concentration adjustment. The other configuration is the same as that in the case of FIG.

Fig. 8 is a system diagram showing the apparatus of the eighth embodiment of the present invention. In the present embodiment, in order to perform batch blending, a load cell 4 is attached to the blending tank 1 of FIG. 4 instead of the liquid level altimeter 2, and the weight of the blending liquid of the blending tank 1 is accurately measured, and the concentration is from the concentration. The measured value is used to calculate the supplementary weight and to control the supplementary weight. The other configuration is the same as that in the case of Fig. 4 .

Next, a control system of the apparatus according to the embodiment shown in Figs. 1 to 8 will be described. In FIGS. 1 to 4, the liquid level of the liquid level meter 2 and the mixing tank 1, the conductivity meter 15 (or the absorptiometer 19), the nitric acid concentration of the etching solution, the absorbance photometer 16 and the moisture concentration of the etching solution, and the light absorption. The phosphorometer 17 (or the densitometer 17) and the phosphoric acid concentration of the etching solution essentially function as independent functions, respectively, and the present invention is characterized in that they complement each other and function. The concentration of the etching solution must be managed to a specific concentration in order to perform etching at an optimum etching rate and to perform etching with an optimum etching profile. In addition, the target value of the nitric acid concentration of the etching solution, the target value of the water concentration, the target value of the phosphoric acid concentration, and the target value of the acetic acid concentration, which are necessary for the quality management of the product substrate, must be advanced in advance according to the operation practice or calculation. Set to each controller.

Hereinafter, an example in which a solution of nitric acid, phosphoric acid, acetic acid, and pure water is mixed as an etching liquid will be described.

The nitric acid concentration of the etching solution must be managed to a specific concentration range in order to exert optimum etching performance. It is necessary to adjust the concentration of nitric acid to a specific target value, for example, 4.0 ± 0.5%.

The inventor of the present invention experimentally reviews the relationship between the nitric acid concentration of the etching solution and the conductivity, and experimentally confirms the nitric acid concentration of the etching solution in the blending tank, and the conductivity of the diluent which is diluted with pure water to a specific ratio. The relationship between them. As shown in FIG. 9, it was confirmed that the conductivity of the diluted solution in which the etching solution was diluted to a specific magnification with pure water was linearly related to the nitric acid concentration of the etching liquid, and the dilution liquid which diluted the etching liquid to a specific magnification with water was detected. The conductivity can be determined by the concentration of nitric acid. As shown in FIGS. 1 and 5, the conductivity meter 15 provided in the conduit 37 is provided with various compensation functions and conductivity controllers 30 for minimizing measurement errors. The measured value of the conductivity of the liquid diluted to a specific magnification with pure water is input to the conductivity controller 30, and the phosphoric acid stock solution, the acetic acid stock solution, the nitric acid stock solution, and the pure water are outputted by the output signal so that the value becomes the target value. At least one of them is automatically controlled by the flow regulating valves 24, 25, 26, and 27, and is supplied to adjust the concentration of nitric acid to a target value.

The inventors of the present invention examined the relationship between the nitric acid concentration of the etching solution and the absorbance by an experiment, and confirmed the correlation between the nitric acid concentration of the etching solution of the mixing tank and the absorbance of the etching solution. The measurement wavelength of the absorbance is preferably in the range of 250 nm to 320 nm in the ultraviolet region, and the sensitivity is particularly suitable in the vicinity of 290 nm. As shown in Fig. 10, it was confirmed that the absorbance of the ultraviolet absorption spectrophotometer having a measurement wavelength of λ = 290 nm was linear with respect to the concentration of nitric acid, and the concentration of nitric acid was accurately measured by measuring the absorbance. As shown in FIGS. 3 and 7, the absorptiometer 19 provided on the line 18 is provided with various compensation functions and absorbance controller 40 for minimizing the measurement error. The absorbance measurement value of the sample liquid introduced from the line 18 is input to the absorbance controller 40, and at least one of the phosphoric acid stock solution, the acetic acid stock solution, the nitric acid stock solution, and the pure water is outputted by the output signal so that the value becomes the target value. Automatically controlled by the flow regulating valves 24, 25, 26, 27, respectively, to adjust the nitric acid concentration to the target value

In addition, the moisture concentration of the etching solution must be managed to a specific concentration range in order to exhibit optimum etching performance. Therefore, it is necessary to blend the water concentration to a specific target value, for example, 16.0 ± 1.0%.

The inventors of the present invention examined the relationship between the water concentration of the etching solution and the absorbance of the etching solution by experimentally reviewing the relationship between the water concentration and the absorbance of the etching solution. The measurement wavelength of the absorbance is preferably in the range of 1920 nm to 1960 nm in the near-infrared region, and the sensitivity is particularly suitable in the vicinity of 1931 nm. As shown in FIG. 11, the linear relationship between the absorbance at the measurement wavelength λ=1931 nm and the water concentration was confirmed, and the water concentration was accurately measured by measuring the absorbance. As shown in Figs. 1, 3, 5, and 7, the absorptiometer 16 provided on the line 18 is provided with various compensation functions and absorbance controllers 31 for minimizing measurement errors. The absorbance measurement value of the sample liquid introduced from the line 18 is input to the absorbance controller 31, and at least one of the phosphoric acid stock solution, the acetic acid stock solution, the nitric acid stock solution, and the pure water is outputted by the output signal so that the value becomes the target value. Automatically controlled by flow regulating valves 24, 25, 26, 27, respectively, to adjust the water concentration to the target value

In addition, the phosphoric acid concentration of the etching solution must be managed to a specific concentration range in order to exhibit optimum etching performance. Therefore, it is necessary to blend the phosphoric acid concentration. For a specific target value, for example, 70.0 ± 1.0%.

The inventors of the present invention have experimentally reviewed the relationship between the phosphoric acid concentration of the etching solution and the absorbance, and found that the measurement wavelength of the absorbance is preferably in the range of 2050 nm to 2200 nm in the near-infrared region, and is particularly suitable in the vicinity of 2101 nm. As shown in Fig. 12, it was confirmed that the absorbance at the measurement wavelength λ = 2101 nm is linear with the phosphoric acid concentration, and the water concentration can be measured by measuring the absorbance. As shown in Figs. 1, 3, 5, and 7, the absorptiometer 17 provided on the line 18 is provided with various compensation functions and absorbance controllers 32 for minimizing measurement errors. The absorbance measurement value of the sample liquid introduced from the line 18 is input to the absorbance controller 32, and at least one of the phosphoric acid stock solution, the acetic acid stock solution, the nitric acid stock solution, and the pure water is outputted by the output signal so that the value becomes the target value. The flow rate adjusting valves 24, 25, 26, and 27 are automatically controlled and supplied to adjust the phosphoric acid concentration to a target value.

Further, the inventors of the present invention examined the relationship between the phosphoric acid concentration of the etching solution and the density by an experiment, and found that as the concentration of phosphoric acid increases, the density also increases. As shown in Fig. 13, it was confirmed that the density was linear with the phosphoric acid concentration, and the phosphoric acid concentration was measured by measuring the density. 1, 3, 5, and 7, the absorptiometer 17 is replaced with a densitometer, and the absorbance controller 32 is replaced with a density controller, which is the same as the function of the absorptiometer 17 and the absorbance controller 32.

Further, the inventors of the present invention can conduct conductivity by measuring the conductivity of the diluent after the etching liquid in the mixing tank by pure water, as shown in Table 1 below, according to the research and analysis of the correlation. The absorbance value of the absorbance photometer (or the absorbance value of the absorbance photometer of the etchant for measuring the nitric acid concentration) and the absorbance photometer of the etchant solution and the absorbance of the phosphoric acid concentration of the etchant (or the densitometer) The characteristic values of the three types of density values are calculated by linear regression analysis (MLR-ILS) to obtain a more accurate concentration of the component of the etching solution. In this case, the acetic acid concentration can be calculated by subtracting the nitric acid concentration, the water concentration, and the phosphoric acid concentration from 100%.

As shown in Fig. 2, the outputs from the measured values of the conductivity meter 15, the absorptiometer 16, and the absorptiometer 17 are input to the multi-component calculator 33, and the multi-component algorithm (multi-regression analysis/multivariate analysis) Method), adjust and control the concentration of the correct etching solution. At least one of the phosphoric acid stock solution, the acetic acid stock solution, the nitric acid stock solution, and the pure water is passed through the flow rate adjusting valve 24 by the output signal of the multi-component calculator 33 so that the nitric acid concentration, the acetic acid concentration, the water concentration, and the phosphoric acid concentration are the target values. , 25, 26, and 27 are automatically controlled, and the supply is adjusted to the target value. The description of FIGS. 4, 6, and 8 is also the same as that of FIG. 2, and therefore will be omitted.

The embodiment of Fig. 1 to Fig. 4 can also be used in the batch blending mode, but it is used in a continuous blending manner. Here, the functional relationship of the control system intended for the apparatus of the first embodiment shown in Fig. 1 will be described. The liquid level altimeter 2 is connected to the liquid level controller shown at the end. When the mixing tank 1 is empty, the liquid level altimeter 2 detects that it is empty, and the phosphate raw liquid, the acetic acid raw liquid, the nitric acid raw liquid and the pure water are respectively passed through the flow regulating valve 24 by the output signal of the liquid level controller. 25, 26, 27 and automatically control the liquid supply, so that the liquid level reaches the set position. In one round of mixing, pure water, phosphoric acid stock solution, acetic acid stock solution, and nitric acid stock solution are used to prepare a once-adjusted acetic acid-containing mixed solution having a concentration of acetic acid larger than that of the etching new liquid, and then supplemented by a phosphoric acid stock solution, a nitric acid stock solution, and pure water. It is also possible to finely adjust to a specific concentration. Further, the output signal of the liquid level controller is such that the phosphoric acid stock solution, the acetic acid stock solution, the nitric acid stock solution, and the pure water have the same concentration as the etching new liquid, and the flow rate adjusting valves 24 and 25 are used. 26, 27 adjust the valve opening and send liquid.

Next, the conductivity meter 15 continuously measures the conductivity of the diluent of the etching solution, and at least one of the phosphoric acid stock solution, the acetic acid stock solution, the nitric acid stock solution, and the pure water is at an appropriate minute flow rate by the output signal of the conductivity controller 30. At least one of the flow rate adjusting valves 24, 25, 26, and 27 adjusts the valve opening degree to supply the liquid, and automatically controls the concentration of the nitric acid to a target value.

When the concentration of nitric acid is small, the conductivity meter 15 continuously measures the conductivity of the diluent of the etching solution, and the output of the conductivity controller 30 adjusts the valve opening degree by the flow regulating valve 26 at a suitable minute flow rate of the phosphoric acid solution. The liquid supply is automatically controlled in such a manner as to achieve a target nitric acid concentration. Further, the absorptiometer 16 continuously measures the water concentration of the etching solution, and at least one of the phosphoric acid stock solution, the acetic acid stock solution, the nitric acid stock solution, and the pure water is at a suitable minute flow rate by the output signal of the absorbance controller 31, by the flow regulating valve 24 At least one of 25, 26, and 27 adjusts the valve opening degree to supply the liquid, and automatically controls the concentration of the nitric acid to be the target value.

When the water concentration is small, the absorption photometer 16 continuously measures the water concentration of the etching liquid, and the liquid output is adjusted by the flow rate adjusting valve 27 at a suitable minute flow rate by the output signal of the absorbance controller 31. It is automatically controlled in such a manner as to become the target water concentration.

Further, the absorptiometer 17 continuously measures the phosphoric acid concentration of the etching solution, and at least one of the phosphoric acid stock solution, the acetic acid stock solution, the nitric acid stock solution, and the pure water is at a suitable minute flow rate by the output signal of the absorbance controller 32, by the flow regulating valve 24 At least one of 25, 26, and 27 adjusts the valve opening degree to supply the liquid, and automatically controls the concentration of the nitric acid to be the target value.

When the phosphoric acid concentration is small, the absorption photometer 17 continuously measures the phosphoric acid concentration of the etching solution, and the liquid crystal is supplied by the flow rate adjusting valve 24 at a suitable minute flow rate by the output signal of the absorbance controller 32. It is automatically controlled in such a manner as to achieve a target concentration of phosphoric acid.

Next, the functional relationship of the control system intended for the apparatus of the second embodiment shown in Fig. 2 will be described. In the present embodiment, it is mainly applied to a case where the nitric acid concentration, the water concentration, the phosphoric acid concentration, and the acetic acid concentration are adjusted in a proper manner. As shown in Fig. 2, the outputs from the measured values of the conductivity meter 15, the absorptiometer 16, and the absorptiometer 17 are input to the multi-component calculator 33, and the multi-component algorithm (multi-regression analysis/multivariate analysis) Method), adjust and control the concentration of the correct etching solution. When the mixing tank 1 is empty, the liquid level altimeter 2 detects that it is empty, and the phosphate raw liquid, the acetic acid raw liquid, the nitric acid raw liquid and the pure water are respectively passed through the flow regulating valve 24 by the output signal of the liquid level controller. 25, 26, 27 and automatically control the liquid supply, so that the liquid level reaches the set position. By adjusting the valve opening degree by the flow regulating valves 24, 25, 26, 27 at a suitable flow ratio in such a manner that the phosphoric acid stock solution, the acetic acid stock solution, the nitric acid stock solution, and the pure water have the same concentration as the etching new liquid. Give liquid. Next, the nitric acid concentration, the acetic acid stock solution, the nitric acid stock solution, and the pure water are passed through the flow regulating valves 24 and 25 by the output signals of the multi-component calculator 33 so that the nitric acid concentration, the acetic acid concentration, the water concentration, and the phosphoric acid concentration become the target values. In addition, 26 and 27 are automatically controlled to supply liquid, and the supply is adjusted to adjust the concentration of each component to the target value. The circulating liquid supply pump 11 is operated by a request signal from a use point, and the liquid supply valve 29 is opened to supply liquid to the point of use. After the liquid supply starts, the liquid level is lowered, so that the liquid level altimeter 2 detects a decrease, and the phosphoric acid stock solution, the acetic acid stock solution, the nitric acid stock solution, and the pure water are respectively passed through the flow regulating valve 24 by the output signal of the liquid level controller. , 25, 26, 27 and automatically control the liquid supply, so that the liquid level returns to the set position. The functional relationship of other control systems is the same as in the case of Figure 1.

[Multi-component calculator 33]

The inventors of the present invention found out that the conductivity of the dilute aqueous solution of nitric acid concentration, the absorbance of the nitric acid concentration, the absorbance of the water concentration, the absorbance of the phosphoric acid concentration, and the density of the phosphoric acid concentration are measured by experiments in the presence of nitric acid, phosphoric acid, and acetic acid. It is not only sensitive to one component, but because they are related to each other, the correct concentration must be obtained by heavy regression analysis.

In addition, the inventors of the present invention found the conductivity values of the three kinds of characteristic values (measuring the conductivity of the dilution liquid after etching the etching liquid in the etching treatment tank for the aluminum film with pure water by the results of the research and analysis of the correlation relationship). The conductivity value of the meter or the absorbance value of the spectrophotometer for measuring the nitric acid concentration of the etching solution, the absorbance value of the spectrophotometer for measuring the water concentration of the etching solution, and the absorbance value of the absorptiometer for measuring the phosphoric acid concentration of the etching solution (or The density value of the densitometer)) is calculated by linear regression analysis (MLR-ILS) to determine the component concentration (nitric acid concentration, water concentration, and phosphoric acid concentration) of the correct etching solution, which can be subtracted from 100%. The calculated nitric acid concentration, water concentration, and phosphoric acid concentration were used to calculate the acetic acid concentration.

Here, the calculation formula of the double regression analysis is exemplified. The heavy regression analysis consists of two stages of correction and prediction. Assuming a heavy regression analysis of the n component system, m calibration standard solutions were prepared. The concentration of the jth component present in the i-th solution is represented by Cij. Here, i=1 to m and j=1 to n. For each of the m standard solutions, p characteristic properties (for example, absorbance or conductivity at a certain wavelength) Aik (k = 1 to p) were measured. The concentration data and the characteristic value data can be collectively represented as a matrix (C, A).

The ranks to which these ranks are assigned are referred to as correction ranks, and are represented by symbols S(Skj; k=1 to p, j=1 to n).

[Math 2]

C=A‧S

From the known C and A (the contents of A are not only the measured values at the same time, but also the heterogeneous measured values may be mixed in. For example, the absorbance and the conductivity), the calculation of S by the rank calculation is a correction phase. At this point you must have p≧n and m≧np. Each element of S is an unknown number, so it is preferable that m>np, and in this case, the minimum second-order calculation is performed as follows.

[Math 3]

S=(A ^T A) ^-1 (A ^T C)

Here, the T-th power represents the transposed rank, and the (-1)-th power represents the retrograde column. When p specific values are measured for the sample liquid having an unknown concentration, and these are set to Au (Auk; k = 1 to p), multiplied by S to obtain a desired concentration Cu (Cuj; j = 1 to n).

[Math 4]

Cu=Au‧S

This is the forecasting phase. By selecting one of the calibration standards 12 (12 calibration standard solutions) as the unknown sample, and using the remaining 11 criteria to obtain the calibration rank, the calculated unknown sample concentration is compared with the known value (weight modulation value). The calculation results of the MLR-ILS calculation by the Leave-One-Out method are shown in Table 1. Table 1 shows the concentrations of phosphoric acid, nitric acid, and water obtained by the near-infrared 2 wavelength (1931, 2101 nm) and 10-fold diluted conductivity.

The multi-component calculator 33 adjusts and controls the concentration of the component of the correct etching liquid by the multi-component algorithm (re-regression analysis method/multivariate analysis method) based on the above-described inventors' knowledge and originality.

The multi-component calculator 33 is connected to a conductivity meter 15, an absorptiometer 16, and an absorptiometer 17.

The multi-component calculator 33, the conductivity and the absorbance input by the conductivity meter 15, the absorptiometer 16, and the absorptiometer 17 are calculated by a multi-component algorithm (re-regression analysis/multivariate analysis). For the correct concentration of the etching solution (nitric acid concentration, water concentration, and phosphoric acid concentration), the acetic acid concentration is calculated by subtracting the calculated nitric acid concentration, water concentration, and phosphoric acid concentration from 100% to make each of these concentrations. At least one of the flow rate adjustment valves 24, 25, 26, and 27 is opened and closed to open and close the flow rate adjustment valve. Thereby, the stock solution or the pure water corresponding to the flow rate control valve to be controlled is supplied into the etching treatment tank 1, and the component concentrations are adjusted.

Next, the functional relationship of the control system intended for the apparatus of the third embodiment shown in Fig. 3 will be described. In this embodiment, instead of measuring the conductivity of the diluent after diluting the etching solution in the mixing tank of FIG. 1 with pure water by a conductivity meter, the nitric acid concentration of the etching solution is detected by an absorption photometer for control. . The functional relationship of other control systems is the same as in the case of Figure 1.

Next, the functional relationship of the control system intended for the apparatus of the fourth embodiment shown in Fig. 4 will be described. In this embodiment, instead of measuring the conductivity of the diluent after diluting the etching solution in the mixing tank of FIG. 2 with pure water by a conductivity meter, the nitric acid concentration of the etching liquid is detected by an absorption photometer for control. . The functional relationship of other control systems is the same as in the case of Figure 2.

In the continuous blending mode, the liquid level of the blending tank is usually controlled to maintain the vicinity of the upper limit height of the full tank. In other words, when the etched liquid to be immersed is sent to the storage tank or the use point and the liquid level is lowered, the etchant is immediately adjusted once, and then the control is adjusted so that the concentration of each component becomes the target value. That is, the liquid level of the mixing tank is maintained at a full state, so that it also has an effective storage tank function.

The embodiment of Figures 5 to 8 is used in a batch blending manner. Here, the functional relationship of the control system that is recognized by the apparatus of the fifth embodiment shown in FIG. 5 will be described. In this embodiment, in order to perform batch blending, a load cell 4 is attached to the blending tank 1 of FIG. 1 instead of the liquid level altimeter 2, and the weight of the blending liquid of the blending tank 1 is accurately measured, according to one blending The concentration and the concentration measurement value are used for concentration adjustment. The etched liquid to be blended is almost completely fed to the storage tank or the use point, and the blending tank 1 is in an empty state. When the mixing tank 1 is in an empty state, the load cell 4 detects the lower limit, and the output signal of the load cell 4 is supplied by the flow rate adjusting valve 27 before the blending weight of the pure water becomes a specific weight.

Next, the output signal of the load cell 4 is supplied by the flow regulating valve 24 until the blending weight of the phosphate stock solution becomes a specific weight. Next, the output signal of the load cell 4 is supplied by the flow rate adjusting valve 25 until the blending weight of the acetic acid stock solution becomes a specific weight. Further, by the output signal of the load cell 4, the liquid is supplied from the flow rate adjusting valve 26 until the blending weight of the nitric acid raw liquid becomes a specific weight. Here, the mixed liquid mixed in the mixing tank 1 is stirred by the circulation pump 11.

Next, the concentration of each component of the sampled mixture is measured by the sampling pump 3. The control of the addition of the phosphoric acid stock solution, the acetic acid stock solution, the nitric acid stock solution, and the pure water is performed in accordance with the measured weight of each raw liquid and the concentration measurement of each component concentration, and is automatically controlled by the flow rate adjusting valves 24, 25, 26, and 27, respectively. The liquid is finely adjusted so as to be the concentration of the target value. Here, the mixed liquid mixed in the mixing tank 1 is again stirred by the circulation pump 11. Next, the concentration of each component of the sampled mixture is measured by the sampling pump 3. When the concentration measurement value of each component concentration falls within the concentration range of the target value, the mixing of one batch is completed. The functional relationship of other control systems is the same as in the case of Figure 1.

Next, the functional relationship of the control system intended for the apparatus of the sixth embodiment shown in Fig. 6 will be described. In the present embodiment, in order to perform batch blending, a load cell 4 is attached to the blending tank 1 of FIG. 2 instead of the liquid level altimeter 2, and the weight of the blending liquid of the blending tank 1 is accurately measured. The component calculator 33 performs correct calculation of the concentration measurement value, calculation of the supplementary weight, and control of the supplementary weight. The etched liquid to be blended is almost completely fed to the storage tank or the use point, and the blending tank 1 is in an empty state. When the mixing tank 1 is in an empty state, the load cell 4 detects the lower limit, and the output signal of the load cell 4 is supplied by the flow rate adjusting valve 27 before the blending weight of the pure water becomes a specific weight. Next, the output signal of the load cell 4 is supplied by the flow regulating valve 24 until the blending weight of the phosphate stock solution becomes a specific weight. Next, the output signal of the load cell 4 is supplied by the flow rate adjusting valve 25 until the blending weight of the acetic acid stock solution becomes a specific weight. Further, by the output signal of the load cell 4, the liquid is supplied from the flow rate adjusting valve 26 until the blending weight of the nitric acid raw liquid becomes a specific weight. Here, the mixed liquid mixed in the mixing tank 1 is stirred by the circulation pump 11. Next, the concentration of each component of the sampled mixture is measured by the sampling pump 3. The multi-component calculator 33 performs the control of the supplementary weight by the calculation of the combined weight of the phosphate raw liquid, the acetic acid raw liquid, the nitric acid raw liquid, and the pure water in accordance with the control of the blending weight of each stock solution and the concentration measurement value of each component concentration. The flow rate adjustment valves 24, 25, 26, and 27 are automatically controlled to supply liquid, and are finely adjusted so as to have a target value. Here, the mixed liquid mixed in the mixing tank 1 is again stirred by the circulation pump 11. Next, the concentration of each component of the sampled mixture is measured by the sampling pump 3. When the concentration measurement value of each component concentration falls within the concentration range of the target value, the mixing of one batch is completed. The functional relationship of other control systems is the same as in the case of FIG. The functional relationship between the control systems of Figs. 7 and 8 is the same as that of Figs. 5 and 6, and therefore will be omitted.

The inventors of the present invention have found that by using the correlation of the respective control functions according to the correlation of the respective control functions as described above, it is possible to easily realize the integration of the etching liquid composition into a certain blending and continuous blending.

Further, as described above, the present invention is not limited to the case where a solution of nitric acid and acetic acid with phosphoric acid or pure water is used as the etching solution, and it is also applicable to a solution of phosphoric acid and nitric acid and pure water as an etching solution, and phosphoric acid and nitric acid. An aqueous solution of at least one of an organic acid, hydrochloric acid, sulfuric acid, or perchloric acid, and the organic acid is an aqueous solution of acetic acid or oxalic acid.

1. . . Blending slot

2. . . Liquid level altimeter

3. . . Sampling pump

4. . . Load cell

11. . . Circulating pump

15. . . Conductivity meter

16. . . Absorbance photometer

17. . . Absorbance photometer (density meter)

19. . . Absorbance photometer

20‧‧‧phosphoric acid supply tank

21‧‧‧Acidate supply tank

22‧‧‧Nitrate liquid supply tank

24‧‧‧phosphoric acid solution flow regulating valve

25‧‧‧Acetate solution flow regulating valve

26‧‧‧Nitrate liquid flow control valve

27‧‧‧Pure water flow control valve

30‧‧‧ Conductivity controller

31‧‧‧Absorbance controller

32‧‧‧Absorbance controller (density controller)

33‧‧‧Multi-component calculator

40‧‧‧Absorbance controller

Fig. 1 is a system diagram of an etching liquid blending apparatus according to a first embodiment of the present invention.

Fig. 2 is a system diagram of an etching liquid blending apparatus according to a second embodiment of the present invention.

Fig. 3 is a system diagram of an etching liquid blending apparatus according to a third embodiment of the present invention.

Fig. 4 is a system diagram of an etching liquid blending apparatus according to a fourth embodiment of the present invention.

Fig. 5 is a system diagram of an etching liquid blending apparatus according to a fifth embodiment of the present invention.

Fig. 6 is a system diagram of an etching liquid blending apparatus according to a sixth embodiment of the present invention.

Fig. 7 is a system diagram of an etching liquid blending apparatus according to a seventh embodiment of the present invention.

Fig. 8 is a system diagram of an etching liquid blending apparatus according to an eighth embodiment of the present invention.

Fig. 9 is a graph showing the relationship between the nitric acid concentration of the etching liquid of the present invention and the conductivity of the diluent.

Fig. 10 is a graph showing the relationship between the nitric acid concentration and the absorbance of the etching liquid according to the present invention.

Figure 11 is a graph showing the relationship between the water concentration and the absorbance of the etching liquid according to the present invention.

Figure 12 is a graph showing the relationship between the phosphoric acid concentration and the absorbance of the etching solution according to the present invention.

Figure 13 is a graph showing the relationship between the phosphoric acid concentration and the density of the etching solution according to the present invention.

1. . . Blending slot

2. . . Liquid level altimeter

3. . . Sampling pump

11. . . Circulating pump

12. . . Pipeline

13. . . Filter for removing fine particles and the like in the etching liquid

14. . . Air valve for circulation mixing

15. . . Conductivity meter

16. . . Absorbance photometer

17. . . Absorbance photometer (density meter)

18. . . Pipeline

20. . . Phosphate stock solution tank

twenty one. . . Acetic acid stock solution tank

twenty two. . . Nitric acid raw liquid supply tank

twenty three. . . N ₂ gas piping

twenty four. . . Phosphate stock flow control valve

25. . . Acetic acid solution flow regulating valve

26. . . Nitric acid raw liquid flow regulating valve

27. . . Pure water flow control valve

29. . . Air valve for liquid supply

33. . . Multi-component calculator

34. . . Pipeline

35. . . Pipeline

36. . . Pipeline

37. . . Pipeline

38. . . Dilution pump

39. . . Pure water pump

Claims (8)

An etchant fluid blending apparatus comprising: a mixing tank for arranging an etching solution for an aluminum film; a tube connected to the mixing tank; and a pump for discharging the etching liquid or the liquid used for the etching liquid to the piping An etchant liquid blending apparatus connected to the etching apparatus by the pipeline, characterized by comprising: a nitric acid concentration detecting/liquid replenishing member, which is configured to dilute the etching liquid in the blending tank with pure water by a conductivity meter At least one of a monoacid stock solution, a mixed acid stock solution, or pure water, wherein the nitric acid concentration of the etching liquid obtained by the conductivity of the diluent or the nitric acid concentration of the etching liquid obtained by detecting the absorbance of the etching liquid by an absorption photometer The replenishing tank replenishing tank and the water concentration detecting/liquid replenishing member are at least a monoacid stock solution, a mixed acid stock solution or pure water according to a water concentration of the etching liquid obtained by detecting the etching liquid by an absorption photometer. A replenishing tank and a phosphoric acid concentration detecting/liquid replenishing member for detecting the absorption of the etching liquid by an absorption photometer Phosphoric acid concentration obtained by concentration of the etchant, or the etchant at a density densitometer detects the etching solution and the resultant single liquid acid, or a mixed acid liquid of at least one water supply to the engagement groove tone. An etchant fluid blending apparatus comprising: a mixing tank for arranging an etching solution for an aluminum film; a tube connected to the mixing tank; and a pump for discharging the etching liquid or the liquid used for the etching liquid to the piping ;borrow An etching liquid mixing device connected to the etching device by the pipe line, comprising: a conductivity meter for detecting a conductivity of a diluent for diluting an etching liquid in the mixing tank with pure water; or detecting the etching liquid An absorbance photometer for nitric acid concentration, an absorptiometer for detecting the water concentration of the etching solution, and an absorptiometer or a densitometer for detecting the phosphoric acid concentration of the etching solution, and a component concentration calculation member for detecting a nitric acid concentration The conductivity value of the conductivity meter or the absorbance value of the absorbance photometer that detects the nitric acid concentration, and the absorbance value of the absorbance photometer that detects the water concentration, and the absorbance value of the spectrophotometer that detects the phosphoric acid concentration or The density value of the density meter of the phosphoric acid concentration is detected, and the component concentration of the etching liquid is calculated by a multi-component algorithm (heavy regression analysis method, multivariate analysis method), and a liquid replenishing member is a monoacid liquid solution. At least one of the mixed acid solution and the pure water is supplied to the aforementioned mixing tank. The etching liquid mixing device according to claim 1 or 2, wherein the etching liquid is an aqueous solution containing phosphoric acid or nitric acid. The etching liquid mixing device according to claim 3, wherein the etching liquid further contains an aqueous solution of at least one of an organic acid, hydrochloric acid, sulfuric acid, and perchloric acid. The etching solution blending device according to claim 4, wherein the organic acid is acetic acid or malonic acid. The etching liquid blending device according to claim 1 or 2, wherein the etching liquid blending device is a continuous blending method. An etchant concentration measuring apparatus comprising: a conductivity meter that detects a conductivity of a diluent of an etching solution for an aluminum film diluted with pure water; or an absorptiometer that detects a concentration of nitric acid of the etching solution, and detects An absorptiometer for determining a water concentration of the etching solution, an absorbance photometer or a densitometer for detecting a phosphoric acid concentration of the etching solution, and a component concentration calculating member for measuring a conductivity value of the conductivity meter of the conductivity. Or the absorbance value of the absorbance photometer of the nitric acid concentration, the absorbance value of the absorbance photometer that detects the water concentration, and the absorbance value of the spectrophotometer that detects the phosphoric acid concentration or the density meter that detects the phosphoric acid concentration. The density value is calculated by a multi-component algorithm (re-regression analysis method/multivariate analysis method). An etchant concentration measuring apparatus according to claim 7, wherein the spectrophotometer for detecting the nitric acid concentration of the etching liquid is an ultraviolet absorption spectrophotometer using a wavelength of an ultraviolet region.