TWI453548B - A method for adjusting the density of the developing solution, a regulating device, and a developing solution - Google Patents

Description

Method for adjusting concentration of developing solution, adjusting device and developing solution

The present invention relates to a method for adjusting a concentration of a developing liquid, a modulating device, and a developing solution, and more particularly to an alkaline modulating image for a developing process of a photoresist used in a process such as a liquid crystal substrate or a printed substrate. The alkali concentration method of the liquid is adjusted to a desired concentration so that a certain developing speed can be maintained, and a method for adjusting the concentration of the developing liquid for achieving higher quality development processing can be ideally performed. A liquid-like modulation device, and a developing liquid which can be obtained by the concentration adjustment method and the modulation device.

In order to perform development processing of a photoresist of a process such as a liquid crystal substrate or a printed circuit board, an aqueous alkali solution containing tetramethylammonium hydroxide (TMAH) or the like as a main component is used as a developing solution. As a result of the increase in the size of the substrate or the progress of the treatment, the alkaline developer has been used in a large amount, and it has been recovered by the use of the developer and then regenerated and supplied to the developing device. However, with repeated use, the processing procedure is stopped moderately, and the alkali concentration is lowered due to the reaction with the acid in the photoresist, the reaction of carbonic acid gas or oxygen in the air, and therefore, in the development process, the photoresist pattern is Since the dimensional accuracy and the film thickness accuracy of the unexposed portion are lowered, it is an important subject to manage the alkali concentration.

For the concentration management of the developing liquid, for example, there is disclosed a management device for managing an alkali-based developing liquid used for development of a photoresist, and a developing device is circulated and supplied with a developing liquid, and Simultaneous management of the cycle A "developing liquid management device" for preventing deterioration of development performance, both of the alkali concentration of the developing solution and the dissolved resin concentration in the developing solution. In the developing solution management device, the concentration of the dissolved resin in the developing liquid is detected by an absorption photometer, the alkali concentration of the developing liquid is detected by a conductivity meter, and then the developing liquid in the apparatus is discharged and the developing liquid is replenished. The stock solution and the pure water or the freshly prepared developing liquid make the alkali concentration, the dissolved resin concentration, and the liquid level of the developing liquid in the apparatus constant.

[Patent Document 1] Japanese Patent No. 2556178

In the production of the substrate, the development process and the etching treatment are not affected by the alkali concentration of the developing solution or the dissolved resin concentration in the developing solution, and it can be seen that it is formed on the mask or the substrate. A phenomenon in which the line width of a pattern such as a circuit fluctuates. In fact, when the developing solution is recycled, the line width (CD value) of the photoresist pattern formed on the substrate or the like by the developing process is gradually deviated from the reference value (design value). tendency. That is, in the development processing, in the repeated processing, the development speed, in other words, the dissolution rate of the photoresist varies, and the dimensional accuracy of the obtained photoresist pattern gradually decreases. As a result, the line width of the pattern formed on the substrate by etching is affected. Therefore, in the supply management of the developing liquid, a management method that does not bring about an improvement in the development speed is desired.

The present invention has been developed in view of the above circumstances, and an object thereof is to provide a method for adjusting a concentration of a developing liquid, which is used for adjusting the use. A method for adjusting the concentration of an alkaline developing solution for developing a photoresist of a process such as a liquid crystal substrate or a printed substrate, which can maintain a constant development speed and can perform higher quality development processing. The method of adjusting the concentration of liquid. Further, another object of the present invention is to provide a developing device for a developing liquid which can be modulated to perform higher-quality developing processing using an alkaline used developing solution recovered by a developing procedure of a photoresist. A modulation device for the developing solution of the developing liquid. Further, another object of the present invention is to provide an alkaline developing solution obtained by using the used developing solution using the above-described concentration adjusting method and the modulating device, which is a high-quality developing image. liquid.

In order to solve the problem, the inventors of the present invention have conducted various reviews and confirmed that the developing solution is mainly affected by the fact that the alkali concentration is maintained at the reference concentration and the dissolved resin concentration is managed, and the carbon dioxide gas in the air is mainly absorbed. The carbonate in the developing solution offsets the dissolution energy of the developing solution, and the dissolution rate of the developing solution is lowered. Further, regarding the influence of the carbonate on the dissolution energy of the developing solution, focusing on the relationship between the CD value and the carbonate concentration in the developing solution, it is found that it is not easily affected by the change in the concentration of the dissolved resin, but The solubility of the developing solution is lowered by a certain tendency due to an increase in the concentration of the carbonate. In addition, it has been found that when the concentration of the alkali solution is increased according to a specific relationship, the concentration of the developer can be maintained at a constant level, and the dissolution of the developer can be maintained at a constant level. invention.

That is, the first aspect of the present invention is for adjusting the use of a photoresist. A method for adjusting the concentration of an alkaline concentration of an alkaline developing solution for development processing, which is characterized in that the alkali concentration of the developing solution and the carbonate concentration in the developing solution are measured, and the development can be performed according to the preparation The alkali concentration is adjusted by the relationship between the alkali concentration of the dissolution energy and the carbonate concentration at which the obtained CD value becomes a certain value.

Further, a second aspect of the present invention is a modulation apparatus for modulating an alkaline developing solution for use in a developing process of a photoresist, characterized in that: a method for modulating a predetermined concentration a developing solution of the developing liquid; supplying the prepared developing liquid to the supply tube of the developing program; receiving the used developing liquid to the recovery tube of the preparation tank; and having a higher concentration of the alkali than the reference concentration a new developing solution stock solution is supplied to the raw material supply pipe of the preparation tank; a concentration meter for detecting the alkali concentration of the developing liquid in the preparation tank and the carbonate concentration in the developing liquid; and detection according to the concentration meter a control device for controlling supply of a developing solution of the developing liquid from the raw liquid supply pipe, wherein the control device is based on an alkali concentration of the developing liquid measured by the concentration meter and a carbonate concentration in the developing liquid, The preliminarily prepared relationship between the alkali concentration and the carbonate concentration which can exhibit the solubility of the CD value obtained by the development process is controlled, and the supply of the developing solution liquid is controlled to have a function of adjusting the alkali concentration.

Further, in the present invention, in order to adjust the alkali concentration with higher precision, the alkali concentration can be adjusted by considering the carbonate concentration and the dissolved resin concentration in the developing solution. That is, the third aspect of the present invention is a method for adjusting the concentration of a developing solution, and a method for adjusting the concentration of the alkali concentration of the alkaline developing solution used for the development processing of the photoresist, which is characterized in that : Determination of the alkali concentration of the imaging solution, The concentration of the carbonate in the liquid and the concentration of the dissolved resin are adjusted according to the relationship between the alkali concentration of the solubility at which the CD value obtained by the development process is constant and the carbonate concentration and the dissolved resin concentration. Alkali concentration.

Further, a fourth aspect of the present invention is a modulating device for a developing liquid, which is a modulating device for modulating an alkaline developing liquid used for developing a photoresist, and is characterized in that it is used for modulation. a concentration developing solution for the developing solution; supplying the prepared developing liquid to the supply tube of the developing program; receiving the used developing liquid to the recovery tube of the preparation tank; and increasing the alkali concentration to a higher concentration than the reference concentration a new developing solution stock solution is supplied to the raw material supply pipe of the preparation tank; a concentration meter for detecting the alkali concentration of the developing liquid in the preparation tank, the carbonate concentration in the developing liquid, and the dissolved resin concentration; The detection concentration of the concentration meter controls a supply device for supplying the liquid of the developing liquid from the raw liquid supply pipe, and the control device is based on the alkali concentration of the developing liquid measured by the concentration meter, and in the developing liquid The carbonate concentration and the dissolved resin concentration, and the relationship between the alkali concentration and the carbonate concentration and the dissolved resin concentration, which are capable of exhibiting a certain value of the CD value obtained by the development process, are controlled in advance. Supplying stock solution having an alkali concentration adjustment function.

According to the present invention, as the concentration of the carbonate in the developing solution increases, the alkali concentration of the developing solution is adjusted according to a specific relationship, and the dissolution energy of the developing solution for the photoresist is maintained constant. Photoreceptor treatment It can maintain a certain development speed and can perform higher quality development processing. Further, depending on the carbonate concentration and the dissolved resin concentration in the developing liquid, the alkali concentration of the developing liquid is adjusted according to a specific relationship, and a higher-quality developing process can be performed.

An embodiment of the method for adjusting the concentration of the developing liquid of the present invention and the apparatus for modulating the developing liquid will be described with reference to the drawings.

The method for adjusting the concentration of the developing liquid of the present invention (hereinafter simply referred to as "concentration adjusting method") is a development processing program for a developing device including a rotary developing device, a coating and developing device, and the like, and is adjusted for use in a photoresist. The method for adjusting the concentration of the alkali concentration of the development solution (hereinafter referred to as "visual liquid"), and the preparation device for the development liquid of the present invention (hereinafter simply referred to as "modulation device") The modulating device for modulating the above-described developing liquid, the present invention is particularly preferably applied to a developing device which is used for a developing device for recovering a photoresist of a process such as a liquid crystal substrate or a printed substrate. The case where the developing solution is reused.

In the present invention, the alkali component of the developing solution may, for example, be an inorganic alkali aqueous solution or a tetrahydric hydroxide composed of an inorganic base such as potassium hydroxide, sodium hydroxide, sodium phosphate or sodium citrate alone or in a mixture. An aqueous solution of an organic alkali such as ammonium (TMAH) or choline. In the case where TMAH is used as the developing solution, the TMAH concentration (alkali concentration) is set to, for example, 2.380% by weight. Further, the developing solution may contain a conventional additive such as a nonionic surfactant or a fluorine-based surfactant.

Further, in the present invention, the "CD value" means the line width of the photoresist pattern obtained on the substrate by the development process. In addition, the "reference concentration" of the base to be described later refers to the concentration of the base (the initial alkali concentration) of the CD value which can be obtained. The CD value described above is the CD value at the time of performing the development processing for a predetermined period of time set in advance, and is the original CD value which is the basis of the evaluation before the change. Further, the base to be used may be a single base, or may be an additive containing the above-mentioned additives, and the solubility of the additive may be increased by the reference concentration of the base when the solid liquid containing the additive is used. The difference is better.

First, a modulation apparatus which is ideally applicable to the implementation of the concentration adjustment method of the present invention will be described. The modulating device of the present invention is a modulating device for modulating a developing liquid used for developing processing as shown in FIG. 4, and modulating the above-described developing liquid using a used developing liquid recovered by a developing program. . The modulation device includes a modulation groove (1) for modulating a predetermined concentration of the developing liquid, and a developing program for supplying the prepared developing liquid to the developing device (9) (hereinafter referred to as "development" Supply tube (2); the used developing solution is supplied to the recovery tube (3) of the brewing tank (1); and a new developing liquid stock solution having a higher alkali concentration than the reference concentration is supplied to a raw liquid supply pipe (6) of the preparation tank (1); a concentration meter (5) for detecting an alkali concentration of the developing liquid in the preparation tank (1) and a carbonate concentration in the developing liquid; and detection according to the concentration meter The concentration is a control device (not shown) for controlling the supply of the developing liquid solution from the raw liquid supply pipe (6).

The modulation tank (1) adjusts the concentration of the developing liquid to a certain target value, and supplies the developing solution whose concentration has been adjusted to the display as needed. The supply tank of the image forming device (9) is constituted by, for example, a container having a corrosion resistance of an internal volume of about 100 to 2,000 liters. In the brewing tank (1), in order to maintain the received developing solution at an equal concentration, a circulation flow path (4) containing a pump (41) as a stirring means of the developing liquid is provided. According to the above-described circulation stirring means, the number of particles generated is smaller than that of the stirring means provided with a screw or the like in the tank, and the contamination of the developing liquid can be reduced.

Further, the used developing solution recovered is adjusted to a constant temperature in the developing device (9), and the developing liquid in the brewing tank (1) is maintained at a substantially constant temperature. However, in order to more accurately measure the concentration of the developing liquid by the concentration meter (5) to be described later, it is preferable to accurately maintain the temperature of the developing liquid in the brewing tank (1) at a constant temperature (for example, 25 ° C). Therefore, in an ideal form, a temperature adjustment means (not shown) including a heater or a cooler is provided in the modulation tank (1) or the circulation flow path (4).

The supply pipe (2) is composed of a flow path from the modulation tank (1) to the developing device (9) and a pump (21) interposed in the flow path, and modulates the modulation groove (1). The developing solution is supplied to the developing device (9). Further, the recovery pipe (3) is constituted by a discharge port (a drain port of the chamber) of the used developing liquid of the developing device (9) to a flow path of the brewing tank (1), and is used for being disposed in the flow path. Or a pump (not shown) on the side of the developing device (9), and the used developing solution is recovered to the brewing tank (1). Further, although not shown, a buffer tank for temporarily storing the used developing liquid may be provided in the recovery pipe (3), and the temperature of the used developing liquid is adjusted to be in the modulation tank (1). Since the developing solution has the same temperature, it is also possible to provide a temperature adjusting means such as a thermostatic bath.

The raw liquid supply pipe (6) is composed of a flow path from the raw liquid supply mechanism (A) (not shown) to the modulation tank (1) and a flow rate adjusting valve (61) interposed in the flow path, and the modulation groove ( 1) When the concentration of the developing liquid in the lower portion is lowered, the liquid level of the developing liquid liquid having a higher concentration than the reference concentration is 20 to 25 wt% in the case of TMAH by the control of the flow rate adjusting valve (61) of the control device to be described later. The concentration of the developing solution stock solution is supplied to the brewing tank (1). The raw liquid supply mechanism (A) mainly conveys the above-mentioned flow path of the preparation tank (1) by the raw liquid storage tank by preserving a raw liquid storage tank having an internal volume of a high concentration of the developing liquid stock solution of about 500 to 3,000 liters. The pump consists of a liquid stock solution.

Further, in the modulating device of the present invention, when the alkali concentration of the developing liquid in the modulating tank (1) is higher than the target concentration, the concentration of the developing liquid is lowered, and therefore, the modulation is usually performed. The tank (1) supplies the dilution water supply pipe (7) of the dilution water. The dilution water supply pipe (7) is composed of a flow path from the dilution water supply mechanism (B) (not shown) to the modulation tank (1) and a flow rate adjustment valve (71) interposed in the flow path. The control device of the control device described later controls the flow rate adjusting valve (71) to supply ultrapure water to the brewing tank (1). As the dilution water supply means (B), a pure water production apparatus including a storage tank and a liquid supply pump is generally used.

Further, in the modulating device of the present invention, in order to reduce the amount of the developing liquid in the modulating tank (1) to a certain amount or less, the developing liquid is replenished, so that a new image having a reference density is provided. The liquid is supplied to the new liquid supply pipe (8) of the brewing tank (1). The new liquid supply pipe (8) is a flow path from the fresh liquid supply mechanism (C) (not shown) to the modulation tank (1) and is interposed in the flow path. The flow rate adjusting valve (81) is configured to supply a developing liquid of a reference concentration (for example, TMAH having a concentration of 2.38 wt%) to the brewing tank (1) by controlling the flow rate adjusting valve (81) by a control device to be described later. The new liquid supply mechanism (C) mainly uses a new liquid storage tank of about 500 to 3,000 liters in total volume for pre-accommodating a new developing liquid, and the above-mentioned flow path to the preparation tank (1) by the new liquid storage tank. It is composed of a liquid pump.

In the modulating device of the present invention, the concentration meter (5) is usually interposed in the above-described circulation flow path in order to more accurately measure the alkali concentration of the developing liquid in the modulating tank (1) and the carbonate concentration in the developing liquid. (4). As the concentration meter (5), a specific concentration meter is used in order to prevent the concentration measurement from being affected by fluctuations in the concentration of the dissolved resin in the developing solution. Specifically, as the concentration meter (5) described above, the lower concentration meter, that is, the temperature of the developing liquid, the ultrasonic wave propagation speed, and the electromagnetic conductivity are measured, and the predetermined temperature, alkali concentration, and carbonic acid are prepared in advance. The relationship between the ultrasonic propagation rate of the salt concentration and the electromagnetic conductivity (matrix), and the multi-component concentration meter for detecting the alkali concentration of the developing liquid and the carbonate concentration in the developing liquid.

The multi-component concentration meter described above is a concentration meter capable of simultaneously measuring the concentrations of two components of a base and a carbonate by measuring the ultrasonic wave propagation speed and the electromagnetic conductivity in a solution at a constant temperature. In other words, when the temperature of the solution is constant, the multi-component concentration meter is based on the principle of the concentration of each component, and the principle of the propagation speed and electromagnetic conductivity of the ultrasonic wave in the specific liquid. It is composed of an ultrasonic transducer, an ultrasonic transmitter, an electromagnetic conductivity converter, an electromagnetic conductivity transmitter, and a microprocessor that performs predetermined calculations.

In the case where the multi-component concentration meter is applied to the measurement of the concentration of the above-described developing liquid, the ultrasonic wave propagation speed measured in advance under a certain temperature condition by various combinations for each alkali concentration and carbonate concentration The relationship with the electromagnetic conductivity is prepared in advance as a matrix, that is, by writing to the microprocessor, the calculated alkali concentration and the carbonate concentration can be accurately estimated from the measured values based on the aforementioned matrix. In addition, as the multi-component concentration meter as described above, for example, a multi-component concentration meter for liquids manufactured by Fuji Industrial Co., Ltd. can be mentioned. Further, in addition to the above-described multi-component concentration meter, as a concentration meter for measuring the alkali concentration, a concentration meter using a bending method using a tortuosity of a measuring fluid or a near-infrared method using a wavelength close to the infrared field can be used. Further, as the concentration meter for measuring the carbonate concentration, for example, a concentration meter using a neutralization titration or the like can be used.

In the modulation apparatus of the present invention, in addition to the operation control of the entire apparatus, the conveyance of the developing liquid solution, the delivery of the dilution water, and the new developing liquid are controlled by the concentration meter (5). Control device for transport (not shown). The control device includes an input device for digitally converting the signals of the measuring devices, an arithmetic processing device such as a program controller or a computer, and an output device for analogizing the control signals from the arithmetic processing device.

The above control device controls the supply of the developing liquid solution from the raw liquid supply pipe (6) based on the detected concentration of the concentration meter (5). That is, the control device is based on the alkali concentration of the developing liquid measured by the concentration meter (5) and the carbonate concentration in the developing liquid, and the insufficient amount of the carbonate concentration and the alkali concentration prepared in advance to the reference concentration. Relationship, in other words, able to send The relationship between the alkali concentration of the solubility of the CD obtained by the development process and the carbonate concentration, which is obtained by the development process, controls the supply of the stock solution and has a function of adjusting the alkali concentration. Thereby, in the modulating device of the present invention, the used developing liquid is recovered by the developing device (9), and a developing liquid having an appropriate alkali concentration can be prepared in the modulating tank (1).

Further, the above-described control device is configured to control the supply of the developing solution liquid, and to control the supply of the dilution water from the dilution water supply pipe (7) and the new display from the new liquid supply pipe (8). Like the supply of liquid. Thereby, in the modulating device of the present invention, the liquid amount of the developing liquid in the modulating tank (1) can be managed to be constant.

Further, in the modulating device of the present invention, in order to prevent contact between the developing liquid or the developing liquid solution and the air, the inside of the system is sealed by an inert gas such as nitrogen. Further, in the modulating device of the present invention, in order to keep the amount of liquid in the system constant, it is provided at an appropriate portion to discharge the remaining used developing liquid to the outside of the system when the developing liquid solution is supplied. mechanism. Although not illustrated, for example, the brewing tank (1) is provided with a flow path or an overflow device for discharging the control valve.

Next, the function of the above-described modulation device and the concentration adjustment method of the present invention will be described. In the concentration adjustment method of the present invention, when the developing liquid is modulated by using the above-described modulation device, first, the used developing liquid discharged from the developing device (9) is recovered to the brewing tank by the collecting pipe (3). (1) Further, while the developing liquid (including the developing liquid used for the used developing liquid) in the brewing tank (1) is circulated in the circulation flow path (4), the mixture is stirred and mixed, and the temperature adjusting means is used. The developing solution is kept at a certain temperature and then measured The alkali concentration of the liquid and the carbonate concentration in the developing solution. As the concentration meter (5), the aforementioned multi-component concentration meter was used.

After measuring the alkali concentration of the developing liquid in the brewing tank (1) and the carbonate concentration in the developing liquid, the flow rate adjusting valve (61) of the raw liquid supply pipe (6) is controlled by the above-described control device to modulate The alkali concentration of the developing liquid in the tank (1) is adjusted to an appropriate concentration. In this case, according to the present invention, the relationship between the alkalinity and the carbonate concentration of the solubility of the carbonate concentration and the alkali concentration which are prepared in advance, and the amount of the base concentration, which is a certain value of the CD value, can be exhibited. The relationship produced is adjusted to a value equal to or higher than the reference concentration in accordance with the measured value of the carbonate concentration. Thereby, the dissolution energy of the developer to the photoresist can be maintained constant. Hereinafter, the above-described idea of the present invention will be more specifically described.

In the case where the developing device is circulated and supplied with the developing liquid, the carbon dioxide gas in the air is absorbed, and carbonate is generated in the developing liquid, and the dissolution of the carbonate and the developing liquid to the photoresist can be offset, resulting in display The dimensional accuracy of the photoresist pattern obtained by the treatment is lowered. As a result, the line width of the circuit pattern formed on the substrate is different from the design width. Further, when the alkali concentration of the developing liquid and the developing time of the developing treatment are set to be constant, the CD value is affected by the concentration and height of the carbonate in the developing liquid to be used.

The effect of the carbonate concentration in the developing solution on the CD value is shown in Fig. 2. 2 is a concentration of 3 to 5 types in the range of 2.20 to 3.27 wt%, and the concentration of each of the 7 kinds of development liquids (TMAH) having different carbonate concentrations is determined to be constant at each concentration. The CD value in the case of time development processing is thicker than the carbonate in the aforementioned developing solution Degree relationship. As shown in Fig. 2, when a newly prepared developing solution having a carbonate concentration of 0 ppm (five kinds having different alkali concentrations) is used, the CD value is 2.77 to 5.16 μm, whereas, for example, a carbonate concentration is used. In the case of a 525 ppm imaging solution (four kinds of alkali concentrations), the CD value is 3.70 to 5.05 μm, and when a developer solution having a carbonate concentration of 1000 ppm (four types having different alkali concentrations) is used, the CD value becomes 3.59. 4.30 μm. That is, the relationship shown in Fig. 2 is shown, and as the concentration of carbonate in the developing liquid increases, the dissolution energy of the developing solution to the photoresist decreases with a certain tendency, and the CD value increases in a constant relationship.

Therefore, in the case of development processing, in order to maintain the CD value to a certain extent, it is necessary to increase the alkali concentration in response to the carbonate concentration. For example, when the CD value is set to 4.00 μm, and a newly prepared developing solution having a carbonate concentration of 0 ppm is used, the alkali concentration (TMAH concentration) is adjusted to 2.38 wt% (reference concentration), but carbonic acid is used again. In the case of a developing solution having a salt concentration of 500 ppm, the alkali concentration (TMAH concentration) must be adjusted to 2.50% by weight, and in the case of using a developing solution having a carbonate concentration of 1000 ppm, the alkali concentration (TMAH concentration) must be adjusted to 2.71. Wt%.

In the above relationship, the relationship between the concentration of alkali and the amount of alkali required to maintain the CD value as a necessary amount of alkali concentration to maintain the CD value (the relationship between the alkali concentration and the shortage of the reference concentration) ), as shown in Figure 1. The relationship between the carbonate concentration and the alkali concentration to the shortage of the reference concentration means that the relationship between the alkali concentration and the carbonate concentration in the case of performing a predetermined development process (processing for obtaining a predetermined CD value) is as described above. Relationship, refers to the concentration of carbonate and the alkali concentration on the basis (use is not The relationship between the insufficient amount of the concentration of the developing solution in the case of the newly prepared developing solution containing carbonate, and the value in the parentheses of the TMAH concentration (alkali concentration) on the vertical axis in the graph of Fig. 1 is a display pair. The insufficient amount of the concentration of the reference concentration (2.38 wt%).

As described above, the present invention focuses on the relationship between the alkali concentration of the developing liquid and the carbonate concentration when the CD value is maintained constant, and corrects the alkali concentration serving as the standard in accordance with the carbonate concentration. Further, in the case of using TMAH, the above-described correction amount (the shortage of the carbonate concentration and the alkali concentration to the reference concentration) shown in Fig. 1 is represented by the following mathematical expression.

[Math. 1] y=8×10 ^{- 8} x ² + 2 × 10 ^{- 4} x (1) where x is the carbonate concentration (ppm) and y is the TMAH concentration (wt%)

In addition, in order to confirm the relationship of FIG. 2, the relationship between the above mathematical formula and FIG. 1 is found, and a plurality of kinds of developing liquids having different alkali concentrations not containing carbonate are prepared (for example, the TMAH aqueous solution actually used). And a plurality of kinds of developing liquids which are different from the carbonate and have a different alkali concentration as a sample, and each of the developing liquids is subjected to a predetermined development process for determining the temperature and the development time, and the respective obtained photoresists are measured. The CD value of the agent pattern. In this case, a calculated amount of dry ice is added to the developing solution containing the alkali concentration of the carbonate, and the calculated concentration of the dry ice is, for example, 100 ppm, 325 ppm, 500 ppm, 1000 ppm, 1500 ppm, or 2000 ppm. Modulate a plurality of species. Further, based on the obtained results, the relationship is estimated based on statistical processing.

According to the present invention, the relationship between the alkali concentration of the dissolution energy capable of exhibiting a CD value and the carbonate concentration is based on the above-described mathematical expression (I) (the relationship of the graph shown in FIG. 1). Adjust the alkali concentration in response to the concentration of carbonate in the imaging solution. In other words, the alkali concentration is adjusted to a value equal to or higher than the reference concentration in accordance with the measured value of the carbonate concentration. Thereby, the dissolution energy of the developing solution can be maintained constant, the dimensional accuracy of the photoresist pattern can be improved, and the CD value can be controlled to be constant. Further, when the carbonate concentration in the developing solution is 0 ppm, the alkali concentration is set to the reference concentration.

Further, when the present invention is implemented by a modulating device or the like, the concentration of the developing solution is adjusted, and in order to obtain a constant CD value, it is necessary to determine the actual alkali concentration in accordance with the concentration of the carbonate. In this case, the relationship between the concentration of the carbonate prepared in advance and the concentration of alkali which can exhibit a predetermined solubility, that is, the alkali concentration and the carbonate concentration of the solubility of the CD having a predetermined value can be exhibited. The relationship (the relationship between the carbonate concentration and the alkali concentration of the aforementioned deficiency) is adjusted to adjust the alkali concentration. The above relationship is shown in the graph of Fig. 1 as the relationship between the carbonate concentration on the horizontal axis and the TMAH concentration on the vertical axis. Therefore, in the case of using TMAH, the above relationship (the relationship between the carbonate concentration and the alkali concentration capable of exhibiting a predetermined solubility) can be expressed by the following mathematical expression.

[Mathematical Formula 2] ^a y = 8 × 10 ⁸ x ² + ² × 10 ^{a 4} x + 2.38 ......... (II) wherein, x is the bicarbonate concentration (ppm), y is the concentration of TMAH (wt%)

In the modulation apparatus of the present invention, the calculation method of the concentration measurement and the control calculation is written to the control device, and the concentration of the modulation tank (1) is adjusted, and the alkali concentration and the display liquid of the developing solution measured by the concentration meter (5) are displayed. For the carbonate concentration in the liquid, the flow rate adjusting valve (61) of the raw liquid supply pipe (6) is controlled according to the above formula (II), and a developing liquid liquid which is insufficient in alkali concentration is added to adjust the alkali concentration to a predetermined amount. The target value. In the case where the alkali concentration is too high in accordance with the above relationship (the relationship of the formula (II)), the dilution water supply pipe (7) is passed through, and the pure water for dilution is supplied to the preparation tank (1).

Further, when a portion of the used used developing liquid is discharged, the amount of the developing liquid in the brewing tank (1) is lowered, and the raw liquid supply pipe (6) and the dilution water supply pipe (7) are transmitted. The developing solution liquid and the pure water are supplied to the brewing tank (1), and the alkali concentration is adjusted by the above operation, whereby the liquid amount of the brewing tank (1) is adjusted within a certain range. Alternatively, the new liquid supply tube (8) is supplied to the brewing tank (1) to adjust the amount of liquid.

The supply control of the developing solution stock solution, the supply control of the dilution water, and the supply control of the new developing liquid are respectively supplied from the dilution water supply mechanism by the supply amount of the developing liquid stock solution from the raw liquid supply mechanism (A). The supply amount of the pure water of (B)) and the supply amount of the developing liquid from the fresh liquid supply pipe (8) are controlled in series. In addition, the so-called asymptotic method disclosed by the "dilution method and dilution device of the alkali imaging stock solution" described in Japanese Patent No. 3741811, for example, can be used.

Specifically, an example of the modulation groove (1) using the above-described asymptotic method For the adjustment of the alkali concentration, in order to adjust the alkali concentration (or the alkali concentration becomes high) to the developing solution in the preparation tank (1), a high concentration of the developing liquid solution (or dilution water) is added to the predetermined concentration, and the following is performed. a process for determining a concentration of a developing solution by a concentration meter (5); and a concentration determined according to the concentration measuring process and a target concentration (concentration obtained by the above formula (II)) The difference is calculated by the amount of the shortage of the stock solution (or the amount of the dilution water added), and the preparation process is performed in an amount of 85 to 99%, preferably 92 to 98%, which is equivalent to the calculated shortage (or addition amount). Further, the modulation process is repeated by the concentration measurement process described above until the measured concentration becomes a value within the region value of the target concentration set in advance. Thereby, the alkali concentration in the developing liquid of the brewing tank (1) can be managed with higher precision.

As described above, in the present invention, the alkali concentration is adjusted to a value equal to or higher than the reference concentration based on the measured value of the carbonate concentration based on the relationship between the carbonate concentration and the alkali concentration prepared in advance and the shortage of the reference concentration. In other words, the alkali concentration is adjusted in accordance with the relationship between the alkali concentration of the dissolution energy at which the CD value becomes a constant value and the carbonate concentration. Thereby, the dissolution energy of the developing solution to the photoresist can be maintained constant. Therefore, according to the present invention, it is possible to maintain a constant development speed for the photoresist in the developing device, and it is possible to further improve the dimensional accuracy and film thickness precision of the photoresist pattern produced by the developing process. Thereby, higher quality development processing can be performed.

Further, in the present invention, in order to adjust the alkali concentration with higher precision, the alkali concentration may be adjusted in accordance with the concentration of the carbonate in the developing solution in accordance with the concentration of the dissolved resin. As described above, in the case of circulating supply of the developing liquid, there will be the following tilting The carbonate is generated in the developing solution, and the photoresist is dissolved in the developing solution due to the development treatment. Although it is only slightly, the dissolved resin lowers the solubility of the developing solution. Therefore, in order to adjust the alkali concentration as described above, it is preferable to correct the concentration of the dissolved resin in the developing solution.

The effect of the dissolved resin concentration in the developing solution on the CD value is as shown in FIG. 3 is a view showing a case where six kinds of developing liquids (using a concentration of 2.38 wt% of TMAH) having different concentrations of a resin (a resin component constituting a photoresist) are dissolved and subjected to development processing for a predetermined period of time. For the relationship between the concentration of the dissolved resin and the change in the CD value, as shown in FIG. 3, for example, the dissolved resin is used as the reference CD value in the case of using a developing solution having a dissolved resin concentration of 0 abs (a developing solution in which the resin is not dissolved). In the case of a developing solution having a concentration of 0.2 abs, the CD value was increased by 0.04 μm, and when a developing solution having a dissolved resin concentration of 0.8 abs was used, the CD value was increased by 0.288 μm. That is, the relationship shown in Fig. 3 is a display, and as the concentration of the dissolved resin in the developing liquid increases, the dissolution energy of the developing solution to the photoresist decreases with a certain tendency, and the CD value increases in a constant relationship.

Therefore, it is possible to find out by the experiment the relationship between the alkali concentration of the developing liquid and the carbonate concentration and the dissolved resin concentration when the CD value is maintained constant. In order to find out the above relationship, a plurality of kinds of developing liquids (for example, an aqueous TMAH solution actually used) having different alkali concentrations different from carbonate and resin components (resin components constituting the photoresist) are prepared, and carbonic acid is contained. A plurality of kinds of developing liquids of the salt and the above-mentioned resin component and different alkali concentration samples are subjected to the same development processing as those of the above-described mathematical expressions (I) and (II) for each of the developing liquids, and the measurement is performed. Resistors obtained by each The CD value of the pattern. The carbonate concentration of each of the developing liquids having different alkali concentrations can be adjusted to an appropriate value of, for example, 100 to 2000 ppm by adding dry ice, and the dissolved resin concentration of each developing solution can be adjusted by the same as described above. The photoresist is dissolved in a calculated amount while measuring the dissolved resin concentration, and the alkali concentration and the dissolved resin concentration are adjusted to, for example, 100 ppm/0 abs, 250 ppm/0.3 abs, 500 ppm/0.6 abs, and 1000 ppm/0.9 abs.

Then, from the results obtained, by statistical processing, for example, the fluctuation amount of the CD value is used as the dependent variable, and the alkali concentration and the above-described carbonate concentration and dissolved resin concentration are used as independent variables, and multi-factor analysis is performed, whereby it is possible to estimate Relationship. In this case, when TMAH is used as the developing solution, the necessary correction amount of the alkali concentration of the developing liquid (the same amount of the alkali concentration as the above-mentioned base concentration) is sufficient to dissolve the CD value. The amount of correction of the usable alkali concentration can be expressed by the following mathematical formula. In the following mathematical formula, the value of TMAH concentration (y) shows the amount of deficiency to the reference concentration.

[Equation 3] y = (2.33 × 10 ^{a 6} x ² + 6.36 × 10 ^{a 4 x + 0.36c) /8.79......... (III} ) wherein, x is the bicarbonate concentration (ppm), c is the concentration of dissolved resin (abs), y is the TMAH concentration (wt%).

Further, the unit abs (absorbance) of the dissolved resin concentration is a unit of the dimensionless amount indicating the concentration of the substance in the liquid by the absorbance indicating the absorption intensity of light of a specific wavelength, as shown in the prior art. The concentration of the dissolved resin in the liquid is expressed by the absorbance at the absorption wavelength (for example, 560 nm) peculiar to the dissolved resin.

In the present invention, the alkali concentration of the developing solution, the carbonate concentration in the developing solution, and the dissolved resin concentration are measured, and the above formula (III) adjusts the alkali concentration in response to the carbonate concentration and the dissolved resin concentration in the developing solution. . In other words, the alkali concentration is adjusted to a value equal to or higher than the reference concentration in accordance with the measured value of the carbonate concentration. Thereby, the dissolution energy of the developing solution can be maintained constant, the dimensional accuracy of the photoresist pattern can be further improved, and the CD value can be further controlled to be constant.

Further, in order to adjust the concentration of the developing solution in the above-described modulation apparatus or the like, it is necessary to determine the actual alkali concentration in accordance with the carbonate concentration and the dissolved resin concentration so that a certain CD value can be obtained. In this case, the alkali concentration is adjusted in accordance with the relationship between the alkali concentration of the dissolution energy at which the CD value becomes a constant value and the carbonate concentration and the dissolved resin concentration. The above relationship can be expressed by the following mathematical expression in the case of using TMAH.

[Mathematical Formula 4] y = (2.33 × 10 ^{a 6} x ² + 6.36 × 10 ^{a 4 x + 0.36c) /8.79+2.38......... (IV} ) wherein, x is the bicarbonate concentration (ppm), c is The dissolved resin concentration (abs), y is the TMAH concentration (wt%).

The preparation device of the preferred embodiment of the present invention is a modulation tank (1), a supply pipe (2), a recovery pipe (3), a raw liquid supply pipe (6), and a concentration meter (5) in the same manner as the device of the above-described configuration. And a control device. In this case, as the concentration meter (5), a multi-component concentration meter capable of detecting the alkali concentration of the developing liquid in the preparation tank, the carbonate concentration in the developing liquid, and the dissolved resin concentration is used. Moreover, the above control device is based on a concentration meter (5) The alkali concentration of the developing liquid, the concentration of the carbonate in the developing solution, the concentration of the dissolved resin, and the alkali concentration and the carbonate concentration and the dissolved resin concentration which can exhibit the solubility of the CD value. The relationship produced controls the supply of the stock solution and has the function of adjusting the alkali concentration.

As the concentration meter (5), the same multi-component concentration meter as described above to which the measurement function of the dissolved resin concentration is added can be used. The multi-component concentration meter is based on the principle that the concentration of each component of the alkali, the carbonate, and the dissolved resin depends on the concentration of the ultrasonic wave, the electromagnetic conductivity, and the absorbance in the specific liquid, depending on the temperature of the solution. The multi-component concentration meter described above measures the temperature of the developing solution, the ultrasonic wave propagation speed, the electromagnetic conductivity, and the absorbance, and the ultrasonic wave propagation speed according to the predetermined temperature, alkali concentration, carbonate concentration, and dissolved resin concentration prepared in advance. Relationship between Electromagnetic Conductivity and Absorbance (Provides the relationship between ultrasonic propagation rate, electromagnetic conductivity, and absorbance measured in advance under a certain temperature condition for each combination of previously prepared alkali concentration, carbonate concentration, and dissolved resin concentration. The matrix) is used to detect the alkali concentration of the developing solution, the carbonate concentration in the developing solution, and the dissolved resin concentration.

In the modulating device of the present invention, the alkali concentration of the developing liquid measured by the concentration meter (5), the carbonate concentration in the developing liquid, and the dissolved resin concentration are the same as those of the above-described apparatus. In the mathematical formula (IV), the flow rate adjustment valve (61) of the raw liquid supply pipe (6) is controlled, and a stock solution liquid solution which is insufficient in alkali concentration is added to adjust the alkali concentration to a predetermined target value.

Furthermore, in accordance with the above relationship (the relationship of the mathematical formula (IV)), When the alkali concentration is too high, the dilution water supply pipe (7) is passed through the dilution water supply pipe (7) in the same manner as the above-described apparatus, and the pure water for dilution is supplied to the preparation tank (1). Further, when the amount of the developing liquid in the modulating tank (1) is lowered, the raw liquid supply pipe (6) and the dilution water supply pipe (7) are passed through, and the developing liquid and the pure water are supplied to the modulating tank (1). Or, a new developing liquid is supplied to the brewing tank (1) through the new liquid supply pipe (8), and the alkali concentration is adjusted by the above operation.

In the present invention, as described above, the alkali concentration of the developing solution, the carbonate concentration in the developing solution, and the dissolved resin concentration are measured, and the alkali concentration and the carbonate concentration and dissolution which can exhibit the solubility of the CD value are constant. The relationship between the resin concentration and the previously prepared relationship adjusts the alkali concentration. Thereby, the dissolution energy of the developer to the photoresist, that is, the development speed can be further maintained constant. Therefore, according to the present invention, it is possible to further improve the dimensional accuracy and film thickness precision of the photoresist pattern produced by the image processing.

As described above, according to the present invention, since the dimensional accuracy and film thickness precision of the photoresist pattern can be further improved in the development processing, higher-quality development processing can be performed. As a result, it is possible to form a pattern with higher precision on the substrate by the etching process. Further, since the alkali concentration is gradually increased in response to an increase in the concentration of the carbonate in the developing liquid, the circulation rate of the developing liquid can be increased, and the development process can be further stabilized. Further, according to the modulating device of the present invention, it is possible to modulate a developing liquid which can perform higher-quality developing processing by using the used developing liquid recovered by the developing program. Moreover, since the developing liquid obtained by the concentration adjusting method and the modulating device of the present invention maintains a constant developing speed for the photoresist, High quality imaging processing is possible.

By the way, a predetermined development process was carried out using a newly-formed developing solution containing no carbonate (the actually used concentration of 2.38 wt% of TMAH), and when the obtained photoresist pattern was confirmed, the CD value was 4.00 μm. . On the other hand, a plurality of used developing liquids having a carbonate concentration of 100 to 2000 ppm are prepared, the TMAH concentration is adjusted according to the relationship of the above formula (II), and the same development as described above is performed using each developing liquid. As a result of the treatment, in the case of using any of the developing liquids, the CD value was 4.00 μm. As a result, it was confirmed that the alkali concentration can be adjusted according to the relationship between the mathematical formulas (I) and (II) (the relationship shown in FIG. 1), and a certain amount of dissolved energy can be maintained.

Further, a used developer liquid having a carbonate concentration of 100 to 2,000 ppm and a dissolved resin concentration of 0 to 2.0 abs was prepared, and the TMAH concentration was adjusted according to the relationship of the above formula (IV). Then, the results of the same development process as described above were carried out using each of the developing liquids, and in the case of using any of the developing liquids, the CD value was 4.00 μm. In the meantime, it was confirmed that the alkalinity concentration was adjusted according to the relationship between the mathematical formulas (III) and (IV), and the solubility was further maintained constant.

1‧‧‧Modulation slot

2‧‧‧Supply tube

21‧‧‧ pump

3‧‧‧Recycling tube

4‧‧‧Circular flow path

41‧‧‧ pump

5‧‧‧ concentration meter

6‧‧‧ stock solution supply tube

61‧‧‧Flow adjustment valve

7‧‧‧Dilution water supply pipe

71‧‧‧Flow adjustment valve

8‧‧‧New liquid supply pipe

81‧‧‧Flow adjustment valve

9‧‧‧Developing device

A‧‧‧ stock solution supply mechanism

B‧‧‧Dilution water supply mechanism

C‧‧‧New liquid supply mechanism

Fig. 1 is a graph showing the relationship between the carbonate concentration and the alkali concentration to the insufficient amount of the reference concentration, and the relationship between the carbonate concentration and the alkali concentration at which a predetermined solubility can be exhibited.

2 is a graph showing the effect of the carbonate concentration in the developing solution on the line width (CD value) of the photoresist pattern obtained by the developing process.

3 is a graph showing the influence of the dissolved resin concentration in the developing liquid on the line width (CD value) of the photoresist pattern obtained by the development processing.

Fig. 4 is a flow chart showing the main structural elements of a modulating device for a developing liquid of the present invention.

1‧‧‧Modulation slot

2‧‧‧Supply tube

3‧‧‧Recycling tube

4‧‧‧Circular flow path

5‧‧‧ concentration meter

6‧‧‧ stock solution supply tube

7‧‧‧Dilution water supply pipe

8‧‧‧New liquid supply pipe

9‧‧‧Developing device

21‧‧‧ pump

41‧‧‧ pump

61‧‧‧Flow adjustment valve

71‧‧‧Flow adjustment valve

81‧‧‧Flow adjustment valve

Claims (4)

A method for adjusting the concentration of a developing solution is a method for adjusting the concentration of an alkali concentration of an alkaline developing solution used for developing a photoresist, characterized in that the alkali component of the developing solution is hydrogen hydroxide. For the determination of the alkali concentration of the developing solution, the concentration of the carbonate in the developing solution, and the concentration of the dissolved resin, the alkali concentration and the carbonate of the solubility of the CD obtained by performing the development process are constant. the concentration of the resin previously dissolved concentrations produced by equation [1] represents the relationship between the alkali concentration adjustment, equation [1] y = (2.33 × 10 ^-6 x at the following ² + 6.36 × 10 ^-4 x + 0.36c) / 8.79 + 2.38 wherein x is the carbonate concentration (ppm), c is the dissolved resin concentration (abs), and y is the TMAH concentration (wt%). The method for adjusting the concentration of a developing solution according to the first aspect of the invention, wherein when the alkali concentration of the developing solution, the carbonate concentration in the developing solution, and the dissolved resin concentration are measured, the concentration meter is used as: The ultrasonic propagation velocity of the liquid, the electromagnetic conductivity and the absorbance of the developing solution, and the relationship between the ultrasonic propagation rate and the electromagnetic conductivity and the absorbance according to the predetermined temperature, alkali concentration, carbonate concentration and dissolved resin concentration prepared in advance. A multi-component concentration meter capable of detecting the alkali concentration of the developing solution, the carbonate concentration in the developing solution, and the dissolved resin concentration. A modulating device for developing a liquid is a modulating device for modulating an alkaline developing solution for use in a developing process of a photoresist, characterized in that the alkali component of the developing solution is tetramethylammonium hydroxide. a modulation tank for modulating a predetermined concentration of the developing liquid; supplying the prepared developing liquid to a supply tube of the developing program; and receiving the used developing liquid to the recovery tube of the preparation tank; a new developing liquid stock solution having a higher concentration than the reference concentration is supplied to the raw liquid supply pipe of the preparation tank; for detecting the alkali concentration of the developing liquid in the preparation tank, the carbonate concentration in the developing liquid, and the dissolved resin concentration a concentration meter; and a control device for controlling the supply of the developing liquid solution from the raw liquid supply pipe according to the detected concentration of the concentration meter, wherein the control device is based on the alkali of the developing liquid measured by the concentration meter The concentration, the carbonate concentration in the developing solution, the dissolved resin concentration, and the alkali concentration and the carbonate concentration and the dissolved resin concentration which are capable of exhibiting a certain value of the CD value obtained by the development process. Equation [2] represented by the relationship, controls the supply of liquid developer liquid, having a function of adjusting the alkali concentration, Equation [2] ^{y = (2.33 × 10 -6 x} 2 + 6.36 × 10 -4 or less in order for the x+0.36c)/8.79+2.38 wherein x is the carbonate concentration (ppm), c is the dissolved resin concentration (abs), and y is the TMAH concentration (wt%). The preparation device of the imaging liquid according to the third aspect of the patent application, wherein the concentration meter is for measuring the ultrasonic wave propagation speed of the developing liquid, the electromagnetic conductivity of the developing liquid, and the absorbance, according to a predetermined temperature and alkali prepared in advance. The relationship between the ultrasonic propagation rate of the concentration, the carbonate concentration and the dissolved resin concentration and the electromagnetic conductivity and the absorbance can detect the alkali concentration of the imaging liquid and the imaging liquid. The multi-component concentration meter of the carbonate concentration and the dissolved resin concentration.