JP3456804B2 - Method and apparatus for manufacturing oxide etching products - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for producing an oxide etching product. More specifically, the present invention relates to maintaining a constant composition of an etching solution for etching an oxide. The present invention relates to a manufacturing method and an apparatus capable of remarkably improving the defect rate of the obtained oxide etching product.

[0002]

2. Description of the Related Art Conventionally, a thin oxide film is formed on the surface of a substrate, an etching resist is formed on the thin film, an appropriate mask is superposed on the thin film, and, for example, irradiated with ultraviolet rays,
Thereafter, it is widely practiced to develop an oxide etching product by developing a desired resist circuit pattern and etching a thin oxide film with an etching solution. For example, an oxide etching product using a thin film of a transparent conductive metal oxide is used as a display element such as a liquid crystal display or a transparent electrode of an input device such as a touch panel. As the above transparent conductive metal oxide, tin oxide, indium oxide, indium tin oxide, etc. are used, and as the etching solution, a mixed aqueous solution of hydrochloric acid-nitric acid is usually used.

[0003]

However, for example, when a mixed aqueous solution of hydrochloric acid-nitric acid is used as the etching solution, hydrochloric acid or water evaporates by heating, or the etching object brings out the etching solution. There is a drawback that the composition of the component always changes. This tendency becomes remarkable when the etching solution is sprayed, and the suction condition of the duct in the etching process also influences. As a result, the performance of the etching solution changes, which affects the finish of the product, resulting in an increase in defective rate and a decrease in reliability. Therefore, generally, as a method of controlling the change in the composition of the etching solution, analysis and analysis of individual solution components are performed.
A method of measuring and replenishing the component according to the changed amount is conceivable, but this method not only complicates the process but also requires complicated replacement of the replenishing solution, and the apparatus becomes large-scaled and the efficiency is high. It was bad.

In recent years, the display element and the input element as described above have become large in size, and have been highly densified and miniaturized. Therefore, a method of manufacturing an oxide etching product with high accuracy and efficiency is required. . Therefore, the present invention prevents an increase in the defective rate and a decrease in reliability of oxide-etched products,
An object of the present invention is to provide a method and an apparatus for producing an oxide etching product, which enables highly accurate and efficient oxide etching processing.

[0005]

As a result of earnest research, the present inventors were able to solve the above-mentioned conventional problems. That is, the present invention provides a step of forming a thin film of tin oxide, indium oxide or indium tin oxide on the surface of a substrate, a step of forming a pattern of an etching resist on the thin film of oxide, and a step of forming the oxide film. Hydrochloric acid thin film
In the method for producing an oxide etching product including the step of etching using an etching solution composed of a nitric acid mixed aqueous solution, the conductivity of the etching solution is measured in the etching step using the etching solution, and the measurement is performed. When the result is fluctuated with respect to the previously determined conductivity, hydrochloric acid-nitric acid mixed aqueous solution having a predetermined composition is replenished to the etching solution, and the conductivity of the etching solution is determined as described above. The composition of the etching solution was kept constant by adjusting the conductivity set in advance, and the conductivity measurement was performed by a cylindrical electromagnetic method covered with a fluororesin insulator. The conductivity measuring electrode has a length of 1.1 to 3.0 times that of the electrode,
Diameter is accommodated in a hollow cylindrical container of 1.1 to 3.0 times of the electrode, the etching liquid to the container, the hollow cylindrical volume
The present invention provides a method for producing an oxide-etched product, which is characterized in that it is introduced into the container from the tangential direction of the inner peripheral surface of the container and allowed to pass therethrough.

[0006]

Further, in the present invention, the weight ratio of hydrochloric acid to nitric acid in the hydrochloric acid-nitric acid mixed aqueous solution of the etching solution is
The method for producing an oxide-etched product is 1: 0.05-5: 5, and the total acid in the etching solution is contained in a ratio of 0.6-0.9 mol per 100 g of the etching solution. It is a thing.

Further, according to the present invention, an etcher for bringing an etching solution into contact with an object to be etched, the etching solution is sampled from the etcher, the conductivity thereof is measured, and a predetermined value is determined based on the obtained conductivity measurement data. a conductivity sensor and a control unit as possible out to sent to the etcher with nitrate mixed aqueous solution in an appropriate amount, - hydrochloric acid composition
Hydrochloric acid having a predetermined composition of the - and a supply solution storage tank for storing the nitric acid mixed aqueous solution, wherein the measurement of the conductivity, off
Cylindrical electromagnetic conductivity measurement covered with a fluorine resin insulator
The length of the electrode is 1.1 to 3.0 times that of the electrode, and the diameter is
It is housed in a hollow cylindrical container having 1.1 to 3.0 times the pole,
The container is filled with the etching solution, and the inner peripheral surface of the hollow cylindrical container
Is introduced into the container from the tangential direction of
The present invention provides an oxide etching product manufacturing apparatus characterized by the above.

Further, the present invention provides a hollow cylindrical container,
An oxide etching product manufacturing apparatus as described above, which is provided with an inflow port and an outflow port for an etching solution, and the inflow port is installed so that the etching solution is introduced into the container from a tangential direction of an inner peripheral surface. Is provided.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION According to the present invention, if the etching conditions such as the etcher, heating temperature, spray pressure, and suction condition of the duct are fixed, the fluctuations of the components of the etching solution are constant, and the fluctuations are different for each component. It was unidirectional, and it was found that there was a significant correlation between the variation in the composition of the etching solution and the conductivity of the etching solution. It is based on the finding that it is possible to detect the composition change of the etching liquid more favorably by accommodating it in the container.

(Step of Forming Oxide Thin Film on Base Material Surface) The method of forming the base material and the oxide thin film in the present invention is not particularly limited and can be freely selected.

Examples of the type of oxide in the present invention include tin oxide, indium oxide and indium tin oxide.

(Step of Forming Etching Resist on Oxide Thin Film) The etching resist that can be used in the present invention and the method of forming the same are not particularly limited and can be freely selected.

(Step of Etching Using Etching Solution) The present invention has a main feature in this step. In the present invention, it is first necessary to clarify in advance the relationship between the conductivity and the variation in the composition of the etching solution. This relationship is simple by fixing the etching conditions such as etcher, heating temperature, spray pressure, suction condition of the duct, etc., by actually manufacturing the oxide etching product, and examining the fluctuation of each component of the etching solution at that time. Can be calculated. If this relationship becomes clear, the concentration of each component of the replenisher can be calculated. As a replenisher for the etching solution, it is convenient and preferable to prepare a hydrochloric acid-nitric acid mixture solution of each calculated concentration as one solution and replenish it to an etcher or the like when a change in conductivity is observed. The hydrochloric acid and the nitric acid may be separately prepared and individually introduced into the etcher.

Examples of the etching solution that can be used in the present invention include a hydrochloric acid-nitric acid mixed aqueous solution exhibiting a good correlation in the fluctuations of the conductivity and the composition of the etching solution. Regarding the quantitative ratio, it is preferable that the weight ratio of hydrochloric acid: nitric acid in the etching solution is 1: 0.05 to 1: 5. When the amount of nitric acid to hydrochloric acid is less than the above, the etching rate tends to decrease, and conversely, when the amount of nitric acid exceeds the above ratio,
The etching resist is likely to be adversely affected.

When the total acid in the etching solution is contained in a ratio of more than 0.4 mol and less than 0.6 mol per 100 g of the etching solution, the rate of change in conductivity is small, so that the composition of the components of the etching solution is small. Since the control is difficult and the control accuracy may be lowered depending on the case, it is preferable not to use the etching solution composition in this range. Further, if the total acid in the etching solution is contained in a ratio of less than 0.2 mol per 100 g of the etching solution, the etching efficiency may decrease, and if the total acid exceeds 0.9 mol, the etching resist is adversely affected. Therefore, the total acid in the etching solution is preferably contained in the range of 0.2-0.4 mol or 0.6-0.9 mol per 100 g of the etching solution, and particularly preferably 0.6-0. It is preferable that it is 0.9 mol because the composition of the replenisher for the etching liquid described later can be easily determined.

The etching temperature may be in the usual range, but if it is low, the etching rate will be small, and if it is high, the composition of the components of the etching solution will change rapidly and the effect on the etching resist will be large, so that it is 20 to 50 ° C. preferable. In the case of etching using a spray, the spray pressure may be in the usual range, but is preferably 1 to 5 kg / cm ^{2 in} view of the etching rate and the physical influence on the etching resist.

Next, the etching process in the present invention will be described with reference to the drawings. FIG. 1 is a process chart for explaining an example of the etching process in the present invention. The etching liquid is applied toward the object to be etched by the spray type etcher 1 provided with the overflow pipe 9 for the etching liquid. The etching solution in the etcher 1 is sent by the solution sending pump 4 through the etching solution solution sending pipe 6 to the conductivity detecting and controlling section 2, where the conductivity is measured. The etching solution after the conductivity measurement is returned to the etcher through the etching solution return pipe 7. Further, the replenishing amount of the etching liquid is estimated based on the measured value of the electric conductivity and converted into a signal, and this signal is sent to the replenishing liquid feeding pump 5 by the control signal wiring 10 to replenish the necessary amount of etching liquid. It is sent from the liquid storage tank 3 to the etcher 1 through the replenishing liquid feeding pump 5 through the replenishing liquid feeding pipe 8.

Further, as shown in FIG.
1, the replenishing liquid feed pump 12 and the replenishing liquid feed pipe 13 may be separately installed as needed.

By appropriately selecting the composition of the hydrochloric acid-nitric acid mixed aqueous solution to be replenished and adjusting the amount of liquid flowing out from the overflow pipe 9, the amount of metal dissolved in the etching liquid can be made constant. As a result, complicated liquid exchange becomes unnecessary.

The replenisher tanks 3 and 11 contain hydrochloric acid-
In order to prevent the decomposition gas of the nitric acid mixed aqueous solution from flowing out and to stop the progress of the decomposition, it is preferable to use a closed container.

Here, the conductivity of the etching solution is measured by the conductivity detecting and controlling section 2 as described above, but the present invention covers the insulator installed in the conductivity detecting and controlling section 2. It is indispensable to house the separated conductivity measuring electrode in a hollow cylindrical container and pass the etching solution through this container. An electromagnetic conductivity measuring coil is usually used to measure the electric conductivity, which has a cylindrical shape with its periphery covered with an insulator such as a fluororesin. If the electrode is not housed in a hollow cylindrical container, the decomposed gas generated from the etching solution adheres to the insulator as bubbles and grows, which interferes with the contact between the etching solution and the coil, and the measurement accuracy of the conductivity is improved. It may decrease. In particular, when the fluororesin is used as the insulator, the bubbles tend to adhere, and when it is remarkable, the conductivity of the etching solution cannot be measured. On the other hand, when the electrode is housed in a hollow cylindrical container, the linear velocity of the etching liquid flowing into the container increases, bubbles do not adhere to the insulator, and the conductivity can be measured stably and accurately.

FIG. 3 and FIG. 4 are perspective perspective views showing an example of the conductivity measuring electrode and a hollow cylindrical container for housing the same. An electromagnetic conductivity measuring coil is covered with a fluororesin, constitutes a conductivity measuring electrode 21, and is housed in a hollow cylindrical container 20. The etchant passes through this container and its conductivity is measured. The container 20 is provided with an etching liquid inlet 22 and an outlet 23. The etching liquid is introduced into the container 20 through the inflow port 22 and comes into contact with the electrode 21, and then the outflow port 23.
And then returned to Etcher 1. Here, the etching solution inlet 22 is attached so that the etching solution flows in the tangential direction of the inner peripheral surface of the container. By doing this, the linear velocity of the inflow of the etching solution becomes faster,
It is preferable that the bubbles of decomposed gas of the etching solution are extremely unlikely to adhere to the insulator. The inflow port 22 may be provided so that the etching liquid flows in the tangential direction of the inner peripheral surface, and may be provided in any direction with respect to the length direction of the container 20.

The installation direction and installation location of the etching solution outlet 23 are not particularly limited, but sufficient contact between the electrode 21 and the etching solution should be considered. The outlet 23 may be oriented in the tangential direction of the inner peripheral surface of the container 20.

It is preferable that the inner peripheral surface of the hollow cylindrical container 20 and the conductivity measuring electrode 21 are not separated from each other as much as possible, and the two do not contact each other (except for the fixing portion 24 of the electrode). For example, in FIG. 3, when the shape of the electrode 21 is cylindrical, the length of the container 20 is 1.1 to that of the electrode.
About 3.0 times, the diameter of the container is 1.1 to 3.0 of that of the electrode.
About twice is good. The installation direction of the electrode 21 in the container 20 is
It may be adjusted as appropriate so that the adhesion of bubbles is minimized, but it is preferable that the length direction of the container 20 and the length direction of the electrode 21 coincide with each other. The shape of the electrode 21 is also preferably cylindrical.

The rate of inflow of the etching solution into the container can be appropriately selected in consideration of the size of the container and the like, but is preferably 2 to 20 liters / minute, for example.

[0027]

The present invention clarifies the correlation between the conductivity and the variation in the composition of the components of the etching solution in the etching step in the method for producing an oxide etching product, while the conductivity of the etching solution changes. Is detected by a conductivity meter, the amount of each component to be replenished is known from the above correlation, and by replenishing this, the composition of the components of the etching solution can be kept constant (conductivity is kept at a set value). It has one feature. Another feature is that the conductivity of the etching solution is measured by accommodating the conductivity measuring electrode covered with an insulator in a hollow cylindrical container and passing the etching solution through this container. . By doing so, the bubbles derived from the etching solution do not adhere to the electrode, and the conductivity can be measured more satisfactorily.

[0028]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited thereto. Example 1 An etching treatment was carried out using the apparatus shown in FIG. 1 and the container and the conductivity measuring electrode shown in FIG. The conductivity measuring electrode is provided with a fluororesin as an insulator, has a columnar shape, and has a length of 20 mm and a diameter of 18 m.
m, with a hole having a diameter of 5 mm in the center. The length of the container is 40 mm and the diameter is 30 mm. Furthermore, the inlet and outlet of the etching solution of this container are pipes with an inner diameter of 5 mm, and the inlet is attached to the lower part of the container so that the etching solution flows in the tangential direction of the inner peripheral surface of the container. The outlet was attached to the center of the container.

In this example, a glass plate was used as the substrate, indium tin oxide was used as the oxide, and thermosetting ink was used as the etching resist. Indium tin oxide was formed on the substrate by sputtering, and an etching resist was formed by screen printing. The size of the indium tin oxide film is 5
The size was 00 mm and the size was 320 mm × 400 mm. Also,
The etching conditions were a temperature of 35 ° C., a spray type etcher, a spray pressure of 1.8 kg / cm ² , an effective etching distance of 2 m, a retained liquid amount of 300 liters, and a conveyor speed of 1.8 m / min. As the components and composition of the etching solution, 35% hydrochloric acid and 67% nitric acid were used, water was added, and hydrochloric acid was 22.0% by weight (0.60 mol per 100 g of the etching solution) and nitric acid was 6.3. weight%
(Etching solution is contained in an amount of 0.10 mol per 100 g), and 310 kg of the obtained mixed solution is charged into an etcher. As a replenisher for keeping the components and composition of the etching solution constant, a mixed aqueous solution of 28.0% by weight of hydrochloric acid and 6.4% by weight of nitric acid was used. The conductivity set value of the control unit was 765 ms / cm. The model used for measuring the conductivity is an electromagnetic induction type conductivity meter. In addition, in the conductivity detection and control unit, the rate of inflow of the etching solution into the container was 5 liters / minute.
The control device was operated to continue the etching while automatically supplying the replenisher, and 40000 sheets of the objects to be etched were processed, but no defective product due to the etching was generated. The amount of replenisher used during this period was 420 kg. In addition,
Table 1 below shows the analysis results of the etching solution for each number of processed sheets. As can be seen from Table 1, the composition of etching components does not change much even when the number of processed wafers increases.

[0030]

[Table 1]

Example 2 An etching process was performed using the apparatus shown in FIG. That is, this device is almost the same as the device of FIG. 1 used in Example 1, but the replenishing liquid storage tank 11, the replenishing liquid feeding pump 12, and the replenishing liquid feeding pipe 13 are separately installed. In this example, a glass plate as the base material,
Indium tin oxide was used as the oxide, and thermosetting ink was used as the etching resist. Indium tin oxide was formed on the substrate by sputtering, and an etching resist was formed by screen printing. The indium tin oxide film has a thickness of 500Å,
The size was 320 mm x 400 mm. The etching conditions were a temperature of 40 ° C., a spray type etcher, a spray pressure of 1.5 kg / cm ² , an effective etching distance of 2 m, a retained liquid amount of 300 liters, and a conveyor speed of 2.5 m / min. Regarding the components and composition of the etching solution, hydrochloric acid is 11.6% by weight (containing 0.32 mol per 100 g of etching solution) and nitric acid is 22.3% by weight.
The mixture was mixed so that it contained 0.35 mol per 100 g of etching solution, and 300 kg of the obtained mixed solution was charged into an etcher. As replenishing liquid, 67% nitric acid (replenishing liquid storage tank 11) and 30% hydrochloric acid (replenishing liquid storage tank 3)
Both acid components were pumped to the etcher by a liquid pump in a volume ratio of 1.0: 2.4, respectively, so that the desired conductivity was achieved. The conductivity set value of the control unit was 770 ms / cm. The conductivity measuring device and conditions were the same as in Example 1. The control device was operated to continue the etching while automatically supplying the replenishing solution, and 50,000 objects to be etched were processed, but no defective product due to the etching was generated.

COMPARATIVE EXAMPLE 1 The conductivity measuring electrode was not housed in a hollow cylindrical container,
The same treatment as in Example 1 was carried out except that it was placed in a liter-shaped rectangular parallelepiped tank as it was, and the etching solution from the etcher was passed therethrough at a rate of 5 liters / minute. As a result, the display value of the conductivity did not exceed the set value and the supply of the replenishing liquid was not performed. Therefore, when 6550 sheets were processed, a defective product was generated due to insufficient etching. The reason why the conductivity did not increase despite the decrease in the acid concentration of the etching solution injection was that air bubbles adhered to the electrodes. The conductivity display value before removing bubbles is 742 ms /
Although it was cm, it was 821 ms / cm when the bubbles were removed. The analysis result of the etching solution shows that the hydrochloric acid concentration is 1
The concentration was 4.2% and the nitric acid concentration was 6.5%.

[0033]

EFFECTS OF THE INVENTION The method of the present invention can maintain the composition of an etching solution for etching an oxide constantly constant and easily, and therefore can significantly improve the defect rate of the obtained oxide etching product. it can.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of an apparatus for carrying out the present invention.

FIG. 2 is a diagram showing an example of another device for carrying out the present invention.

FIG. 3 is a perspective view showing a hollow cylindrical container housed in a conductivity detection and control section of an apparatus for carrying out the present invention and a conductivity measuring electrode housed in the container.

FIG. 4 is a perspective view showing a hollow cylindrical container housed in a conductivity detection and control unit of an apparatus for carrying out the present invention and a conductivity measuring electrode housed in the container.

[Explanation of symbols]

1 Etcher 2 Conductivity detection and control unit 3,11 Replenisher tank 4 Liquid feed pump 5,12 Replenisher liquid feed pump 6 Etching liquid delivery pipe 7 Etching liquid return pipe 8,13 Supply liquid supply pipe 9 Overflow piping 10 Control signal wiring 20 Hollow cylindrical container 21 Conductivity measurement electrode 22 Inlet 23 Outlet

Front page continuation (72) Inventor Yoshikatsu Kubota 7-35 Higashiohisa, Arakawa-ku, Tokyo Asahi Denka Kogyo Co., Ltd. (56) Reference JP-A-63-184726 (JP, A) JP-A-63-171886 (JP, A) JP 63-57784 (JP, A) JP 61-4233 (JP, A) JP 60-114579 (JP, A) JP 57-140339 (JP, A) JP-A-52-34795 (JP, A) JP-A-7-176853 (JP, A) JP-A-6-138067 (JP, A) JP-A-4-249757 (JP, A) JP-A-4-242160 ( JP, A) JP-A-4-158254 (JP, A) Actual development: 2-14061 (JP, U) JP-B-55-33018 (JP, B2) Patent 3406079 (JP, B2) (58) Fields investigated (Int.Cl. ⁷ , DB name) C23F 1/00 C23F 1/08 C23F 1/16 C03C 15/00 G01N 27/07 H01L 21/306

Claims (4)

(57) [Claims] 1. A step of forming a thin film of tin oxide, indium oxide or indium tin oxide on the surface of a substrate,
In the method for producing an oxide etching product, which comprises the step of forming a pattern of an etching resist on the oxide thin film and the step of etching the oxide thin film with an etching solution consisting of a hydrochloric acid-nitric acid mixed aqueous solution, In the step of etching using an etching solution, the conductivity of the etching solution is measured, and when the measurement result fluctuates with respect to a predetermined conductivity, hydrochloric acid having a predetermined composition is used. By replenishing the etching solution with a nitric acid-mixed aqueous solution and adjusting the conductivity of the etching solution to the previously determined conductivity, the composition of the etching solution is kept constant. measurements of conductivity, fluorine cylindrical electromagnetic conductivity measurement electrode covered with an insulator resin, the electrode length
1.1 to 3.0 times the diameter, 1.1 to 3.0 times the diameter of the electrode
Of the hollow cylindrical container, and the etching solution is placed in the container from the tangential direction of the inner peripheral surface of the hollow cylindrical container.
A method for producing an oxide-etched product, characterized in that the oxide-etched product is introduced into and passed through. 2. The weight ratio of hydrochloric acid: nitric acid in the hydrochloric acid-nitric acid mixed aqueous solution of the etching solution is 1: 0.05.
The method for producing an oxide-etched product according to claim 1, wherein the total acid content in the etching solution is 1: 5, and the total acid content is 0.6 to 0.9 mol per 100 g of the etching solution. 3. An etcher for bringing an etching liquid into contact with an object to be etched, and the etching liquid is sampled from the etcher, the conductivity thereof is measured, and hydrochloric acid having a predetermined composition is obtained based on the obtained measurement data of the conductivity. - a conductivity sensor and a control unit that can be <br/> be fed to the etcher with nitrate mixed aqueous solution in an appropriate amount, hydrochloride having a predetermined composition of the - and replenishing water reservoir for storing the nitric acid mixed aqueous solution, Where the measurement of the conductivity is performed on the fluororesin insulator.
Cover the columnar electromagnetic conductivity measuring electrode with
1.1 to 3.0 times the pole and 1.1 to 3.0 in diameter
It is housed in a double hollow cylindrical container and the etching is performed in the container.
From the tangential direction of the inner peripheral surface of the hollow cylindrical container,
Was introduced into the vessel, <br/> oxide etch product manufacturing apparatus characterized that you performed by passing. 4. A hollow cylindrical container is provided with an inlet and an outlet for an etching solution, and the inlet is such that the etching solution is introduced into the container from a tangential direction of an inner peripheral surface. The oxide etching product manufacturing apparatus according to claim 3 , which is attached to the device.