KR20090094217A - Method for regulating concentration of developing solution, apparatus for preparing the developing solution, and developing solution - Google Patents

Abstract

This invention provides a method for regulating the concentration of a developing solution, which can regulate the alkali concentration of an alkaline developing solution used in a photoresist development process so that high-quality development treatment can be carried out, and an apparatus for preparing the developing solution. In the method for regulating the concentration of a developing solution, the concentration of an alkali in the developing solution and the concentration of a carbonate in the developing solution are specified, and the alkali concentration is regulated based on a previously provided relationship between alkali concentration and carbonate concentration, which can realize such a dissolving capability that can render the CD value obtained by the development treatment constant. The apparatus for preparing a developing solution comprises a preparation tank, a feed line for feeding a developing solution to a development process, a recovery line for receiving a used developing solution, a stock solution feed line for feeding a fresh developing solution stock to the preparation tank, a concentration meter for detecting the concentration of an alkali in the developing solution and the concentration of a carbonate in the developing solution, and a control unit forcontrolling the feed of the developing solution stock based on a specific relation.

Description

Method for regulating concentration of developer, manufacturing apparatus and developer {Method for regulating concentration of developing solution, apparatus for preparing the developing solution, and developing solution}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for adjusting the concentration of a developer, a manufacturing apparatus, and a developer, and in particular, a method for adjusting the alkali concentration of an alkaline developer used for developing a photoresist in a manufacturing process such as a liquid crystal substrate or a printed circuit board. It is possible to maintain the development speed and obtain a concentration control method of the developer to be adjusted to an appropriate concentration so as to enable higher quality development treatment, a production apparatus for developing the developer suitable for the implementation of the concentration adjustment method, and a concentration control method and a production apparatus. It relates to a developer that can be.

In developing processes of a photoresist in manufacturing processes, such as a liquid crystal substrate and a printed circuit board, the aqueous alkali solution which has tetramethylammonium hydroxide (TMAH) etc. as a main component is used as a developing solution. Such alkaline developer is currently being used in large quantities due to the increase in substrate size and the progress of the process. From the standpoint of cost reduction, the alkaline developer is recovered and supplied to the developing process. However, as the use is repeated, the alkali concentration decreases due to reaction with acid in the resist, reaction with carbon dioxide gas or oxygen in the air, etc. during process stoppage, thereby reducing the dimensional accuracy of the resist pattern and developing the unexposed portion in the development process. Since film thickness precision falls, it is important to manage alkali concentration uniformly.

Regarding the concentration control of the developer, for example, an apparatus for managing an alkaline developer used for developing a photoresist, wherein both the alkali concentration of the developer to be circulated and the dissolved resin concentration in the developer are circulated and supplied to the developer. The "developer management apparatus" which manages and prevents deterioration of image development performance is disclosed. In such a developer management apparatus, the dissolved resin concentration in the developing solution is detected by a light absorption photometer, the alkali concentration of the developing solution is detected by a conductivity meter, and the alkali level, the dissolved resin concentration, and the liquid level of the developing solution in the apparatus are constant. The developing solution in the apparatus is discharged, and the stock solution and pure water of the developing solution are supplied, or the newly prepared developing solution is supplied.

Patent Document 1: Patent No. 2561578

BRIEF DESCRIPTION OF THE DRAWINGS It is a graph which shows the relationship between the shortage with respect to the reference concentration of carbonate concentration and alkali concentration, and the relationship between the carbonate concentration and the alkali concentration which can exhibit predetermined | prescribed solubility.

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

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

It is a flowchart which shows the main component of the manufacturing apparatus of the developing solution which concerns on this invention.

Explanation of the sign

1: manufacturing tank

2: supply line

21: pump

3: recovery line

4: circulating flow path

41: pump

5: densitometer

6: stock solution supply line

61: flow control valve

7: dilution water supply line

71: flow control valve

8: New liquid supply line

81: flow control valve

9: developer

A: Stock Solution

B: dilution water supply mechanism

C: New fluid supply mechanism

Disclosure of Invention

Problems to be Solved by the Invention

By the way, in the manufacture of a substrate, even though the alkali concentration of the developing solution and the dissolved resin concentration in the developing solution are constantly controlled, when the development treatment and the etching treatment are performed, the line width of a pattern such as a photomask or a circuit formed on the substrate is A change is seen. In fact, when the developer is recycled, the line width (CD width) of the photoresist pattern such as a circuit formed on the substrate by the development treatment tends to gradually deviate from the reference value (design value). That is, the developing speed, in other words, the dissolution rate with respect to the photoresist fluctuates while repeating the process in the developing process, and the dimensional accuracy of the resulting resist pattern gradually decreases. As a result, the line width of the pattern formed in a board | substrate by etching is having an influence. Therefore, in the supply management of the developing solution, an improved management method that does not cause a change in the developing speed is desired.

The present invention has been carried out in view of the above circumstances, and an object thereof is a concentration control method for adjusting an alkali concentration of an alkaline developer used for developing a photoresist in a manufacturing process such as a liquid crystal substrate, a printed substrate, and the like. It is to provide a method for adjusting the concentration of the developer can be maintained, and a higher quality development treatment. Another object of the present invention is to provide a developing apparatus for producing a developer capable of producing a developer having a higher quality development by using an alkaline used developer recovered from a developing process of a photoresist. Another object of the present invention is to provide a developer capable of high-quality development as an alkaline developer obtained by using the above-described concentration adjusting method and production apparatus and effectively using the used developer.

Means to solve the problem

MEANS TO SOLVE THE PROBLEM In order to solve the said subject, as a result of various examination by the present inventors, although the alkali concentration is maintained at the reference concentration in the developing solution and the dissolved resin concentration is managed, the carbonate produced in the developing solution mainly absorbs the carbonic acid gas in air. It was confirmed that the dissolving ability of was canceled and the dissolution rate of the developer was reduced. In addition, as a result of focusing on the relationship between the CD value and the concentration of carbonate in the developer, the effect of carbonate on the solubility of the developer was not significantly affected by the change in the concentration of the dissolved resin. It was found that the degradation tends to be constant. When the concentration was adjusted to increase the alkali concentration based on a specific relationship with the increase in the carbonate concentration in the developer, the present inventors found that the developing ability of the developer with respect to the photoresist can be kept constant.

That is, the first aspect of the present invention is a concentration adjusting method for adjusting the alkali concentration of an alkaline developer used for developing a photoresist, the alkali concentration of the developing solution and the carbonate concentration in the developing solution can be measured and developed. It exists in the density | concentration control method of the developing solution characterized by adjusting alkali concentration on the basis of the previously created relationship of alkali concentration and carbonate concentration which can exhibit solubility so that CD value may become constant value.

In addition, a second aspect of the present invention is a manufacturing apparatus for producing an alkaline developer used for developing a photoresist, a manufacturing tank for producing a developer having a predetermined concentration, a supply line for supplying the developed developer to a developing process, A recovery line for receiving the finished developer into the production tank, a stock solution supply line for supplying a new developer stock solution having a higher concentration than the standard concentration to the production tank, a concentration meter for detecting the alkali concentration of the developer in the production tank and the carbonate concentration in the developer, A control device is provided to control the supply of the developer stock solution from the stock solution supply line on the basis of the detected concentration by the densitometer, and the controller includes an alkali concentration of the developer measured by the densitometer and a carbonate concentration and development of the developer. To ensure that the CD value It exists in the developing apparatus of the developing solution characterized by having the function of adjusting supply of a developing solution stock solution based on the previously created relationship between the alkali concentration which can exhibit solubility, and the carbonate concentration, and adjusting alkali concentration.

In the present invention, the alkali concentration may be adjusted in consideration of the dissolved resin concentration together with the carbonate concentration in the developer in order to adjust the alkali concentration with higher accuracy. That is, the third aspect of the present invention is a concentration adjusting method for adjusting the alkali concentration of an alkaline developer used for developing a photoresist, wherein the alkali concentration of the developer, the carbonate concentration in the developer and the dissolved resin concentration are measured, and the developer is treated. The alkali concentration is adjusted on the basis of a previously prepared relationship between the alkali concentration, the carbonate concentration, and the dissolved resin concentration, which can exert the solubility so that the CD value obtained by the constant value becomes a constant value. exist.

Further, a fourth aspect of the present invention is a manufacturing apparatus for producing an alkaline developing solution used for developing a photoresist, a manufacturing tank for producing a developer having a predetermined concentration, a supply line for supplying the developed developer to a developing process, A recovery line for accepting the finished developer to the production tank, a stock solution supply line for supplying the developer with a new developer stock solution having an alkali concentration higher than the reference concentration, an alkali concentration of the developer in the production tank, a carbonate concentration in the developer and a dissolved resin concentration A densitometer to detect and a control device for controlling the supply of the developer stock solution from the stock solution supply line on the basis of the detected concentration by the densitometer, wherein the controller includes the alkali concentration of the developer measured by the densitometer, the developer Carbonate concentration, dissolved resin concentration, development It has a function to control the supply of developer stock solution based on the pre-created relationship between alkali concentration, carbonate concentration and dissolved resin concentration which can exert the solubility so that the CD value can be constant. It exists in the manufacturing apparatus of the developing solution.

Effects of the Invention

According to the present invention, the alkali concentration of the developer is adjusted on the basis of a specific relationship as the carbonate concentration in the developer is increased, and in order to maintain the solubility of the developer in the photoresist, The developing speed can be maintained, and higher quality development can be performed. Further, according to the carbonate concentration and the dissolved resin concentration in the developing solution, by adjusting the alkali concentration of the developing solution on the basis of a specific relationship, a higher quality developing treatment is possible.

Implement the invention  Best form for

EMBODIMENT OF THE INVENTION Embodiment of the density | concentration adjustment method of the developing solution which concerns on this invention, and one Embodiment of the manufacturing apparatus of a developing solution is demonstrated with reference to drawings.

The concentration control method of the developer according to the present invention (hereinafter abbreviated as "concentration control method") is an alkaline developer used for developing a photoresist in a developing process including a developing device such as a spin developer device, a coater developer device, or the like. (Hereinafter abbreviated as "developer") is a concentration adjusting method for adjusting the alkali concentration, and the developing apparatus for producing a developer (hereinafter abbreviated as "manufacturing apparatus") according to the present invention is a manufacturing apparatus for producing the developer. The present invention is particularly well suited for reusing a used developer recovered from a developing process of a photoresist in a manufacturing process such as a liquid crystal substrate or a printed circuit board as a developing process.

In the present invention, as the alkali component of the developer, an inorganic alkaline aqueous solution composed of an inorganic alkali or a mixture of inorganic alkalis such as potassium hydroxide, sodium hydroxide, sodium phosphate and sodium silicate, tetramethylammonium hydroxide (TMAH) and trimethyl monoethanol ammonium Organic alkali aqueous solution, such as hydroxide (Corine), etc. are mentioned. When TMAH is used as the developer, the TMAH concentration (alkali concentration) is set to 2.380 wt%, for example. Moreover, the developer may contain conventionally well-known additives, such as a nonionic surfactant and a fluorochemical surfactant.

In the present invention, the "CD value" refers to the line width of the photoresist pattern obtainable on the substrate by the development treatment. In addition, the "reference concentration" of alkali mentioned later means the density | concentration (initial alkali concentration) of the alkali from which the following CD values are obtained. The above-mentioned CD value is a CD value when the development process for a predetermined time is set in advance, and is an original CD value serving as an evaluation standard before the value is changed. The alkali used as such standard may be an alkali alone or an additive as described above may be included, and it is preferable to add a difference in solubility by the additive with respect to the standard concentration of the alkali when the actual liquid containing the additive is used.

First, the manufacturing apparatus suitable for implementation of the density adjustment method of this invention is demonstrated. As shown in Fig. 4, as a manufacturing apparatus for producing a developer used in the developing process, the developer is produced using the used developer recovered from the developing process. Such a manufacturing apparatus uses a manufacturing tank 1 for producing a developer of a predetermined concentration, a supply line 2 for supplying the manufactured developer to a developing process (hereinafter referred to as a "developing apparatus") such as a developing apparatus 9, and the like. The recovery line which can accept this finished developer to the manufacturing tank 1, the stock solution supply line 6 which supplies the new developing solution stock solution whose alkali concentration is higher than a reference concentration to the manufacturing tank 1, and the manufacturing tank 1 It is provided with the density meter 5 which detects the alkali concentration of a developing solution, and the carbonate concentration in a developing solution, and the control apparatus (not shown) which controls supply of a developing solution stock solution from the raw-stock supply line 6 based on the detected density by the said density meter, have.

The production tank 1 is a supply tank for adjusting the concentration of the developer to a constant target value and supplying the developer with the concentration control to the developing device 9 as needed, and having, for example, corrosion resistance of about 100 to 2000 liters. It is composed by one container. In the production tank 1, a circulation passage 4 in which the pump 41 is opened is provided as a stirring means for the developer in order to maintain the contained developer at a uniform concentration. The stirring means by the circulation as described above has less generation of particles as compared with stirring apparatuses such as screws provided in the tank, and can reduce contamination of the developer.

In addition, the used developer recovered is controlled to a constant temperature in the developing apparatus 9, and the developer in the production tank 1 also maintains a substantially constant temperature. However, in order to more accurately measure the concentration of the developing solution by the densitometer 5 described later, it is preferable to maintain the temperature of the developing solution in the production tank 1 accurately at a constant temperature (for example, 25 ° C). And in the preferable aspect, the manufacturing tank 1 or the circulation flow path 4 is provided with the temperature control means (not shown) containing a heater and a cooler.

The supply line 2 consists of a flow path from the manufacturing tank 1 to the developing device 9 and a pump 21 remodeled in the flow path, and the developing solution produced in the manufacturing tank 1 is the developing device 9. It is supposed to supply. In addition, the recovery line 3 is composed of a flow path from the discharge port (drain of the chamber) of the used developer to the manufacturing tank 1, and the pump provided on the flow path or the developing device 9 side ( (Not shown) to recover the used developer to the production tank 1. In addition, although not shown, the recovery line 3 may be provided with a buffer tank for temporarily storing the used developer, and in order to adjust the temperature of the used developer to a temperature equivalent to that of the developer in the production tank 1. Temperature control means such as this may be provided.

The stock solution supply line 6 is composed of a flow path from the stock solution supply mechanism A (not shown) to the production tank 1 and a flow rate control valve 61 opened in the flow path. When the concentration is lowered, a developer stock solution having a concentration higher than the reference concentration, for example, a developer stock solution having a concentration of 20-25% by weight in the case of TMAH, is controlled by the control of the flow regulating valve 61 by the controller described later. ) To be supplied. The stock solution supply mechanism (A) is a stock solution storage tank having a volume of about 500 to 3000 liters for accommodating a high concentration of the stock solution solution in advance, and a pump for feeding the developer stock solution from the stock solution tank in the flow passage leading to the production tank (1). It is mainly composed.

Moreover, in the manufacturing apparatus of this invention, in order to reduce the density | concentration of the developing solution when the alkali concentration of the developing solution in the manufacturing tank 1 becomes higher than a target concentration, the dilution water supply line which supplies dilution water to the manufacturing tank 1 normally. (7) is provided. The dilution water supply line 7 is composed of a flow path from the dilution water supply mechanism B (not shown) to the production tank 1 and a flow rate regulating valve 71 opened in the flow path. Ultrapure water is supplied to the manufacturing tank 1 by control of the flow regulating valve 71. As a dilution water supply mechanism B, the pure water manufacturing apparatus containing a storage tank and a liquid feed pump is used normally.

In addition, in the manufacturing apparatus of the present invention, when the amount of the developer in the production tank 1 is reduced to a certain amount or less, a new liquid supply line 8 for supplying a new developer with a reference concentration to the production tank 1 to replenish the developer is provided. It is provided. The new liquid supply line 8 is constituted by a flow path from the new liquid supply mechanism C (not shown) to the manufacturing tank 1 and a flow rate regulating valve 81 opened in the flow path, and regulates the flow rate by a control device described later. By the control of the valve 81, the developing solution 1 is supplied with a reference concentration developer (for example, TMAH having a concentration of 2.38% by weight). The new liquid supply mechanism (C) is mainly composed of a new liquid saving tank having an internal volume of about 500 to 3000 liters for accommodating a new developer solution, and a pump for feeding the developer solution from the new liquid saving tank to the flow passage leading to the manufacturing tank (1). .

In the manufacturing apparatus of the present invention, the densitometer 5 is usually mounted in the circulation passage 4 described above in order to more accurately measure the alkali concentration of the developer in the production tank 1 and the carbonate concentration in the developer. As the densitometer 5, a specific densitometer is used to measure the concentration with high accuracy without being influenced by the fluctuation of the dissolved resin concentration in the developer. Specifically, the densitometer 5 measures the temperature of the developer, the ultrasonic wave propagation rate and the electron conductivity, and based on the relationship (matrix) between the ultrasonic wave propagation rate and the electron conductivity at a predetermined temperature, alkali concentration and carbonate concentration. A multi-component densitometer is used for detecting the alkali concentration of the developer and the carbonate concentration in the developer.

The multi-component densitometer is a densitometer which can simultaneously measure the concentration of two components of alkali and carbonate in real time by measuring the ultrasonic wave propagation rate and the electron conductivity in a solution at a constant temperature. That is, the multi-component concentration meter is based on the principle that the ultrasonic wave propagation rate and the electron conductivity in the liquid are uniquely specified according to the concentration of each component when the temperature of the solution is constant. For example, when measuring the two components, the ultrasonic transducer, It consists of an ultrasonic transmitter, an electron conductivity transducer, an electron conductivity transmitter and a microprocessor which performs a predetermined operation.

In the case of applying to the concentration measurement of the developer as described above in the multi-component concentration meter, by preliminarily preparing the relationship between the ultrasonic wave propagation rate and the electron conductivity measured in advance under a constant temperature condition for each combination of alkali concentration and carbonate concentration, That is, by writing to the microprocessor, it is possible to accurately estimate the alkali concentration and the carbonate concentration from the measured values based on the matrix. As said multicomponent concentration meter, the multicomponent concentration meter for liquids of Fuji-Kyosha Co., Ltd. is mentioned, for example. As the densitometer for measuring alkali concentrations in addition to the multicomponent densitometer described above, a densitometer using a refraction method for measuring the refractive index of a fluid, or a densitometer using a near infrared method for measuring the wavelength of the near infrared region may be used. As a densitometer to be used, a densitometer using neutralization titration can be used.

In the manufacturing apparatus of the present invention, in addition to the operation control of the entire apparatus, a control apparatus for controlling the feeding of the developer stock solution, the feeding of the dilution water, and the feeding of the new developing solution based on the measurement of the densitometer 5 as described above (not shown). It is provided. Such a control device includes an input device for digitally converting a signal of each measuring device, an arithmetic processing device such as a program controller and a computer, and an output device for analog converting a control signal from the arithmetic processing device.

The control device described above is configured to control the supply of the developer stock solution from the stock solution supply line 6 on the basis of the detected concentration by the densitometer 5. That is, the control device is a relationship between the alkali concentration of the developer measured by the densitometer 5 and the carbonate concentration in the developer, the shortage between the pre-made carbonate concentration and the reference concentration of the alkali concentration, and, if reduced, a CD that can be obtained by developing. It has a function of controlling the supply of the developer stock solution based on a previously created relationship between the alkali concentration and the carbonate concentration capable of exhibiting solubility so that the value becomes a constant value. Thereby, the used developer from the developing apparatus 9 is collect | recovered in the manufacturing apparatus of this invention, and the developing solution of the alkali density appropriate in the manufacturing tank 1 can be manufactured.

The control device is also configured to control the supply of the dilution water from the dilution water supply line 7 and the supply of the new developer from the new solution supply line 8 together with the supply of the developer solution. Thereby, in the manufacturing apparatus of this invention, the liquid amount of the developing solution in the manufacturing tank 1 can be managed uniformly.

In addition, in the manufacturing apparatus of the present invention, in order to prevent contact between the developer and the developer stock solution, the inside of the system is sealed by an inert gas such as nitrogen. In the manufacturing apparatus of the present invention, a mechanism for discharging excess used developer out of the system is provided at an appropriate location in order to maintain the amount of liquid in the system. Although not shown, for example, the manufacturing tank 1 is provided with a flow path or overflow device for drain including a control valve.

Next, the concentration control method of the present invention together with the function of the manufacturing apparatus will be described. In the method for adjusting the concentration of the present invention, in producing the developer using the above-described manufacturing apparatus, first, the used developer discharged from the developing apparatus 9 is recovered by the recovery line 3 to the manufacturing tank 1. In addition, the developer (developing solution containing the spent developer) of the production tank 1 is circulated through the circulation passage 4 and mixed with stirring to maintain the developer at a constant temperature by means of temperature control means, and then the alkali concentration of the developer and the developer The carbonate concentration in it is measured by the densitometer (5). As the densitometer 5, the above-mentioned multicomponent densitometer is used.

After measuring the alkali concentration of the developer in the production tank 1 and the carbonate concentration in the developer, the flow control valve 61 of the feed solution supply line 6 is controlled by the control device, and the alkali of the developer in the production tank 1 is controlled. Adjust the concentration to the appropriate concentration. In this case, the present invention is based on the relationship between the carbonate concentration prepared in advance and the deficiency with respect to the reference concentration of the alkali concentration, that is, the pre-created relationship between the alkali concentration and the carbonate concentration capable of exhibiting solubility so that the CD value becomes a constant value. The alkali concentration is adjusted to a value equal to or higher than the reference concentration in correspondence with the measured value of the carbonate concentration. Thereby, the dissolution ability of the developing solution with respect to a photoresist can be kept constant. The above idea of the present invention will also be described in detail below.

When the developer is recycled and supplied to the developing process, carbonic acid gas in the air is sucked in to form a carbonate in the developing solution, and this carbonate cancels the solubility of the developing solution in the photoresist, and thus the dimensions of the resist pattern obtained by developing. Decreases the precision. As a result, the line width of the circuit pattern formed on the substrate is different from the design width. Therefore, if the alkali concentration of the developing solution and the developing time are set constant in the developing treatment, the CD value is highly correlated with the carbonate concentration in the used developing solution.

The influence of the carbonate concentration in the developer on the CD value is as shown in FIG. FIG. 2 illustrates the development of a predetermined time for each concentration by adjusting the alkali concentration (TMAH concentration) to 3 to 5 kinds of concentrations ranging from 2.20 to 3.27% by weight with respect to seven kinds of developing solutions (TMAH) having different carbonate concentrations. Although the relationship between the CD value in the case and the carbonate concentration in the developer was confirmed, as shown in FIG. 2, when a newly prepared developer (five kinds having different alkali concentrations) having a carbonate concentration of 0 ppm was used, the CD value was 2.77 to For example, when a developer having a carbonate concentration of 525 ppm (four kinds having different alkali concentrations) is used for a 5.16 μm thickness, a developer having a CD value of 3.70 to 5.05 μm and a carbonate concentration of 1000 ppm (four kinds having different alkali concentrations) is used. In this case, the CD value is 3.59 to 4.30 mu m. That is, the relationship shown in Fig. 2 shows that the solubility of the developer in the photoresist decreases with a constant tendency and the CD value increases in a constant relation with the correspondence of the carbonate concentration in the developer.

Therefore, when it is going to keep CD value constant in developing, it is necessary to make alkali concentration high according to carbonate concentration. For example, if the CD value is set to 4.00 µm, when using a newly prepared developer having a carbonate concentration of 0 ppm, the alkali concentration (TMAH concentration) is adjusted to 2.38% by weight (reference concentration), but a developer having a carbonate concentration of 500 ppm is used. When used, the alkali concentration (TMAH concentration) must be adjusted to 2.50% by weight, and when using a developer solution of 1000 ppm of carbonate concentration, the alkali concentration (TMAH concentration) must be adjusted to 2.71% by weight.

From the above relationship, regarding the alkali concentration required in the developer, the relationship between the carbonate concentration when the CD value is kept constant and the required correction amount of the alkali concentration (the relationship between the shortage with respect to the reference concentration of the alkali concentration) is shown in FIG. Can be represented as: The relationship between the carbonate concentration and the shortage with respect to the reference concentration of the alkali concentration is a relationship derived in advance from the relationship between the alkali concentration and the carbonate concentration in the case of performing a constant development treatment (a treatment capable of obtaining a constant CD value) as described above. It means the relationship between the carbonate concentration and the deficiency with respect to the reference alkali concentration (the concentration of the said developer when using the newly manufactured developer which does not contain a carbonate). In the graph of FIG. 1, the values in parentheses of the TMAH concentration (alkali concentration) of the longitudinal axis indicate a deficiency of the concentration relative to the reference concentration (2.38 wt%).

The present invention focuses on the relationship between the alkali concentration and the carbonate concentration in the developer in the case where the CD value is kept constant as described above, so that the reference alkali concentration is corrected according to the carbonate concentration. And in the case of using TMAH, the correction amount (lack of the reference concentration of carbonate concentration and alkali concentration) shown in FIG. 1 can be expressed by the following approximation formula:

Formula (I)

y = 8 x 10 ^-8 x ² + 2 x 10 ^-4 x ... (I)

Where x is the carbonate concentration (ppm) and y is the TMAH concentration (% by weight).

In order to confirm the relationship of FIG. 2 and to discover the approximation formula and the relationship of FIG. 1, a plurality of newly prepared alkali concentrations containing no carbonates (such as a TMAH aqueous solution actually used), carbonates, A plurality of types of developing solutions as samples having different alkali concentrations are prepared, and a prescribed developing treatment in which the temperature and the developing time are made constant is performed for each developing solution, and the CD values of the obtained resist patterns are measured, respectively. At this time, the developer of each alkali concentration containing carbonate is added with a calculated amount of dry ice while checking the carbonate concentration so that the carbonate concentration becomes 100 ppm, 325 ppm, 500 ppm, 1000 ppm, 1500 ppm, 2000 ppm, for example. It manufactures multiple types. And a relational expression is estimated by statistical process from the obtained result.

In the present invention, the above formula (1) (the relationship of the graph shown in FIG. 1) is based on the above, that is, on the basis of a pre-created relationship between the alkali concentration and the carbonate concentration which can exhibit the solubility that the CD value becomes constant. The alkali concentration is adjusted in accordance with the carbonate concentration in the developer. 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. As a result, the dissolving ability of the developer can be kept constant, the dimensional accuracy of the resist pattern can be increased, and the CD value can be controlled constantly. When the carbonate concentration in the developing solution is 0 ppm, the alkali concentration is set to the reference concentration.

In carrying out the present invention in a manufacturing apparatus or the like, it is necessary to determine the actual alkali concentration according to the carbonate concentration so as to obtain a constant CD value in the concentration control of the developer. In that case, the relationship between the carbonate concentration prepared in advance and the alkali concentration capable of exhibiting a predetermined solubility, that is, the pre-created relationship between the alkali concentration and the carbonate concentration capable of exhibiting solubility so that the CD value becomes a constant value (carbonate concentration and Alkali concentration is adjusted based on the relationship with alkali concentration which added the shortfall mentioned above). This 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, when TMAH is used, 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 approximation formula:

expression( II )

y = 8 x 10 ^-8 x ² + 2 x 10 ^-4 x + 2.38 ... (II)

Where x is the carbonate concentration (ppm) and y is the TMAH concentration (% by weight).

In the production apparatus of the present invention, an algorithm for concentration measurement and a control operation is written in the control apparatus, and the concentration control in the production tank 1 determines the alkali concentration of the developer measured by the densitometer 5 and the carbonate concentration in the developer. Basically, the flow rate regulating valve 61 of the stock solution supply line 6 is controlled in accordance with the above formula (II), and the stock solution corresponding to the shortage of alkali concentration is added to adjust the alkali concentration to a predetermined target value. In addition, when the alkali concentration is too high in view of the relationship (relationship of formula (II)), pure water for dilution is supplied to the production tank 1 through the dilution water supply line 7.

When a part of the recovered used developer is discharged and the amount of the developer in the production tank 1 is reduced, the developer stock solution and the pure water are produced through the stock solution supply line 6 and the dilution water supply line 7. ) And the amount of liquid in the production tank 1 is adjusted to a certain range by adjusting the alkali concentration by the above operation. Alternatively, a new developer is supplied to the manufacturing tank 1 through the new liquid supply line 8 to adjust the liquid amount.

The supply control of the developer stock solution, the supply control of the dilution water, and the control of supply of the new developer solution respectively supply the supply amount of the developer stock solution from the stock solution supply mechanism (A), the supply amount of pure water from the dilution water supply mechanism (B), and the new drug supply line (8). Can be carried out by cascading the supply amount of the developer from the step C). And in these controls, for example, the so-called asymptotic method disclosed by " dilution method and dilution device of alkaline developing stock solution " described in Japanese Patent No. 3741811 can be used.

Specifically, the adjustment of the alkali concentration, for example, in the production tank 1 using the above asymptotic method is carried out by using a high concentration of developer stock solution (or dilution water) in the developer in the production tank 1 in which the alkali concentration has decreased (or the alkali concentration has increased). ), The difference between the concentration measurement step of measuring the concentration of the developer solution by the densitometer 5 and the concentration measured in the concentration measurement step and the target concentration (concentration obtained from the formula (II)) On the basis, the deficiency (or the amount of dilution) of the developer stock solution is calculated, and a manufacturing process is performed to supply an amount corresponding to 85 to 99%, preferably 92 to 98% of the calculated deficiency (or the amount of addition). . The manufacturing process is repeated from the concentration measuring process until the measured concentration becomes a value within a predetermined target concentration threshold. Thereby, the alkali concentration in the developing solution can be managed by the manufacturing tank 1 with much higher precision.

As mentioned above, based on the relationship between the carbonate concentration previously prepared and the deficiency with respect to the reference concentration of alkali concentration, the alkali concentration is adjusted to the value more than a reference concentration according to the measured value of carbonate concentration. In other words, the alkali concentration is adjusted based on a previously created relationship between the alkali concentration and the carbonate concentration capable of exhibiting solubility so that the CD value becomes a constant value. This keeps the solubility of the developing solution with respect to a photoresist constant. Therefore, according to the present invention, it is possible to maintain a constant developing speed with respect to the photoresist in the developing process, and to further increase the dimensional accuracy and the film thickness precision of the resist pattern produced in the developing process, thereby further improving the development of high quality. It becomes possible.

In the present invention, the alkali concentration may be adjusted in accordance with the dissolved resin concentration together with the carbonate concentration in the developer in order to adjust the alkali concentration with higher accuracy. As described above, when the developer is recycled and supplied, carbonate is generated in the developer, and the photoresist is dissolved in the developer by the developing treatment, and the dissolved resin tends to decrease the solubility of the developer slightly. Therefore, in adjusting the alkali concentration as described above, it is preferable to correct according to the dissolved resin concentration in the developing solution.

The influence of the dissolved resin concentration in the developing solution on the CD value is as shown in FIG. 3. Fig. 3 shows the relationship between change in dissolved resin concentration and CD value when a certain time development is carried out with six different types of developer (TMAH at a concentration of 2.38% by weight) which differ in the concentration of the dissolved resin (resin component constituting the photoresist). However, as shown in Fig. 3, the CD value when a developer having a dissolved resin concentration of 0.2 abs is used, for example, with respect to a reference CD value when a developer having a dissolved resin concentration of O abs (a developer in which the resin is not dissolved) is used. When this increased by 0.04 µm and a developer having a dissolved resin concentration of 0.8 abs, the CD value increased by 0.288 µm. That is, the relationship shown in FIG. 3 shows that the solubility of the developing solution with respect to the photoresist decreases with a constant tendency with the increase of the dissolution resin concentration in the developing solution, and the CD value increases in a constant relationship.

The relationship between the alkali concentration, the carbonate concentration and the dissolved resin concentration in the developer when the CD value is kept constant can be found from the experiment. In order to discover the relationship, a plurality of newly prepared developer solutions having different alkali concentrations (eg, aqueous TMAH solutions actually used) containing no carbonate and a resin component (a resin component constituting the photoresist), a carbonate and the resin component are used. A plurality of types of developing solutions as samples containing different alkali concentrations, and subjected to the same developing process for each of the developing solutions as described above when the formulas (I) and (II) were led, and the CD values of the obtained resist patterns, respectively. Measure As for the carbonate concentration of the developer having different alkali concentrations, the same value as in the case described above was adjusted to an appropriate value of, for example, 100 to 2000 ppm by addition of dry ice, and the dissolved resin concentration was measured for the dissolved resin concentration of each developer. 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 by dissolving the photoresist in a calculated amount.

From the results obtained, the relational expression can be estimated by performing multifactor analysis, for example, by using the statistical processing as the dependent variable and the alkali concentration, the carbonate concentration and the dissolved resin concentration as independent variables. As a result, for example, when TMAH is used as the developer, the alkali solution for exerting the solubility of the alkali concentration in the developer (as described above, a deficiency relative to the reference concentration of the alkali concentration), i.e., the CD value, becomes constant. The correction amount of the concentration can be expressed by the following approximation formula. In the following formula | equation, the numerical value of TMAH concentration (y) shows the deficiency with respect to a reference concentration.

expression( III )

y = (2.33 x 10 ^-6 x ² + 6.36 x 10 ^-4 x + 0.36c) /8.79 ... (III)

Where x is the carbonate concentration (ppm), c is the dissolved resin concentration (abs), and y is the TMAH concentration (% by weight).

The unit abs (absorbance) of the dissolved resin concentration is a dimensionless unit in which the concentration of the substance in the liquid is expressed by absorbance, which is a measure of the absorption intensity of the substance with respect to a specific wavelength of light, as is well known. The concentration can be expressed as absorbance at the absorption wavelength (for example, 560 nm) peculiar to the dissolved resin.

In the present invention, the alkali concentration of the developer, the carbonate concentration and the dissolved resin concentration in the developer are measured, and the alkali concentration is adjusted in accordance with the carbonate concentration and the dissolved resin concentration in the developer based on the above formula (III). 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. As a result, the dissolving ability of the developer can be kept constant, the dimensional accuracy of the resist pattern can be further increased, and the CD value can be further controlled constantly.

Further, in carrying out the present invention in the above-described production apparatus, it is necessary to determine the actual alkali concentration in accordance with the carbonate concentration and the dissolved resin concentration, in order to obtain a constant CD value in the concentration control of the developer. In this case, alkali concentration is adjusted based on the previously created relationship between the alkali concentration, the carbonate concentration, and the dissolved resin concentration which can exhibit the solubility so that the CD value becomes a constant value. The relationship can be expressed by the following approximation when using TMAH:

expression( IV )

y = (2.33 x 10 ^-6 x ² + 6.36 x 10 ^-4 x + 0.36c) /8.79 + 2.38 ... (IV)

Where x is the carbonate concentration (ppm), c is the dissolved resin concentration (abs), and y is the TMAH concentration (% by weight).

The production apparatus of the preferred embodiment of the present invention is manufactured in the production tank 1, the supply line 2, the recovery line 3, the stock solution supply line 6, the densitometer 5 and the control apparatus in the same manner as the apparatus of the above-described aspect. It is composed by. In this case, as the concentration meter 5, a multicomponent concentration meter for detecting the alkali concentration of the developer in the production tank, the carbonate concentration in the developer and the dissolved resin concentration is used. The control apparatus described above includes an alkali concentration, a carbonate concentration, and a dissolved resin concentration capable of exhibiting solubility so that the alkali concentration of the developing solution measured by the densitometer 5, the carbonate concentration and the dissolved resin concentration, and the CD value in the developing solution become constant values. On the basis of the previously created relationship with, it has a function of controlling the supply of the developer stock solution to adjust the alkali concentration.

As the densitometer 5, the same multicomponent densitometer as described above to which the measuring function of dissolved resin concentration is added can be used. Such a multi-component concentration meter is based on the principle that when the temperature of the solution is constant, the propagation rate, electron conductivity and absorbance of the ultrasonic wave in the liquid are uniquely specified according to the concentration of each component of alkali, carbonate and dissolved resin. The multi-component concentration meter measures the concentration of the developer, the ultrasonic wave propagation rate, the electron conductivity and the absorbance, and the relationship between the ultrasonic wave propagation rate, the electron conductivity and the absorbance at a predetermined temperature, alkali concentration, carbonate concentration and dissolved resin concentration (preliminary The alkali concentration of the developer and the carbonate concentration in the developer are based on a matrix which defines the relationship between the ultrasonic wave propagation speed, the electron conductivity and the absorbance measured in advance for each combination of the prepared alkali concentration, carbonate concentration and dissolved resin concentration under a constant temperature condition. And to detect the dissolved resin concentration.

In the production apparatus of the present invention, the stock solution supply line is formed according to the above formula (VI) in the same manner as in the above-described apparatus based on the alkali concentration of the developing solution measured by the densitometer 5, the carbonate concentration in the developing solution and the dissolved resin concentration. The flow rate regulating valve 61 of 6) is controlled, and the alkali concentration is adjusted to a predetermined target value by adding a developer stock solution suitable for the shortage of alkali concentration.

When the alkali concentration becomes too high in view of the relationship (relationship of formula (VI)), the pure water for dilution is supplied to the production tank 1 through the dilution water supply line 7 in the same manner as in the above-described apparatus. do. On the other hand, when the amount of the developer in the production tank 1 is reduced, the developer solution and the pure water are supplied to the production tank 1 through the stock solution supply line 6 and the dilution water supply line 7, or the new solution supply line. The new developing solution is supplied to the manufacturing tank 1 through (8), and alkali concentration is adjusted by the said operation.

In the present invention, the alkali concentration of the developer, the carbonate concentration in the developer, and the dissolved resin concentration are measured as described above, and the previously created relationship between the alkali concentration, the carbonate concentration, and the dissolved resin concentration capable of exhibiting solubility so that the CD value becomes a constant value. Adjust the alkali concentration based on. Thereby, the solubility of the developing solution with respect to a photoresist, ie, developing speed, can be maintained more constant. Therefore, according to this invention, the dimensional precision and film thickness precision of the resist pattern produced by the image development process can be improved further.

As described above, according to the present invention, since the dimensional accuracy and the film thickness precision of the resist pattern can be further improved in the developing process, a higher quality developing process is possible. As a result, a pattern can be formed on the substrate in an etching process with high accuracy. In addition, since the alkali concentration is gradually set higher with the increase in the carbonate concentration in the developing solution, the recycling rate of the developing solution can be increased, and the developing process can be further stabilized. Moreover, according to the manufacturing apparatus of this invention, the used developing solution collect | recovered from the developing process can be used, and the developing solution which can develop higher quality development can be manufactured. The developing solution obtained by the concentration adjusting method and the manufacturing apparatus of the present invention maintains a constant developing speed with respect to the photoresist, so that high quality developing treatment can be performed.

Therefore, the prescribed development treatment was carried out using a newly prepared developer (TMAH having a concentration of 2.38% by weight) that was not containing carbonate, and the obtained resist pattern was confirmed to have a CD value of 4.00 mu m. On the other hand, several kinds of used developer with carbonate concentration of 100-2000 ppm are prepared, the TMAH concentration is adjusted based on the relationship of Formula (II) mentioned above, and each developer is used for the same developing treatment as above. As a result, even if any developer was used, the CD value was 4.00 m. By this, it was confirmed that constant solubility can be maintained by adjusting the alkali concentration based on the relationship between the formulas (I) and (II) (the relationship shown in FIG. 1).

In addition, several kinds of used developing solutions having a carbonate concentration of 100 to 2000 ppm and a dissolved resin concentration of 0 to 2.0 abs were prepared, and the TMAH concentration was adjusted based on the relationship of Formula (IV) described above. As a result of the same development treatment as above using each developer, the CD value was 4.00 µm even when any developer was used. It was confirmed by this that also about the developing solution which melt | dissolved resin, the solubility can be maintained more uniformly by adjusting alkali concentration on the basis of the relationship of Formula (III) and (VI).

Claims (14)

A concentration adjusting method for adjusting the alkali concentration of an alkaline developer used for developing a photoresist, wherein the alkali concentration of the developer and the carbonate concentration in the developer are measured, and the solubility is maintained so that the CD value obtained by the development treatment becomes a constant value. A method for adjusting the concentration of a developer, based on a pre-created relationship between an alkali concentration and a carbonate concentration capable of exerting an alkali. The method for adjusting the concentration of a developer according to claim 1, wherein the alkali component of the developer is tetramethylammonium hydroxide, and the relationship between the previously prepared alkali concentration and carbonate concentration is expressed by the following approximation formula: y = 8 x 10 ^-8 x ² + 2 x 10 ^-4 x + 2.38 Where x is the carbonate concentration (ppm) and y is the TMAH concentration (% by weight). The method of measuring the alkali concentration of the developer and the carbonate concentration in the developer, as a concentration meter, measures the ultrasonic wave propagation rate and the electron conductivity of the developer in the developer, and the predetermined temperature, alkali concentration and carbonate prepared in advance. A method for controlling the concentration of a developer using a multi-component concentration meter capable of detecting the alkali concentration of the developer and the carbonate concentration in the developer based on the relationship between the ultrasonic wave propagation rate and the electron conductivity at the concentration. A manufacturing apparatus for producing an alkaline developer used for developing a photoresist, comprising: a manufacturing tank for producing a developer having a predetermined concentration, a supply line for supplying the manufactured developer to a developing process, and a used developer for receiving the used developer in the manufacturing tank; A recovery line, a stock solution supply line for supplying a new developer stock solution having a higher concentration than the reference concentration to the production tank, a concentration meter for detecting the alkali concentration of the developer in the production tank, and a carbonate concentration in the developer, and a detection concentration with the concentration meter And a control apparatus for controlling the supply of the developer stock solution from the stock solution supply line, wherein the controller has an alkali concentration of the developer measured by the densitometer, a carbonate concentration in the developer, and a CD value obtained by developing. Can exhibit solubility to be a constant value The apparatus for manufacturing a developing solution, characterized in that by controlling the supply of the developer stock solution prepared in advance by the relationship between the alkali concentration and the carbonate concentration of the base has a function of adjusting the alkali concentration. The apparatus for producing a developer according to claim 4, wherein the alkali component of the developer is tetramethylammonium hydroxide, and the relationship between the alkali concentration and the carbonate concentration previously prepared is expressed by the following approximation formula: y = 8 x 10 ^-8 x ² + 2 x 10 ^-4 x + 2.38 Where x is the carbonate concentration (ppm) and y is the TMAH concentration (% by weight). 6. The densitometer according to claim 4 or 5, wherein the densitometer measures the ultrasonic wave propagation rate and the electron conductivity of the developer in the developer, and based on the relationship between the ultrasonic wave propagation rate and the electron conductivity at a predetermined temperature, alkali concentration and carbonate concentration. The manufacturing apparatus of the developing solution which is a multicomponent concentration meter which can detect the alkali concentration of a developing solution, and the carbonate concentration in a developing solution. A concentration adjusting method for adjusting the alkali concentration of an alkaline developer used for developing a photoresist, wherein the alkali concentration of the developer, the carbonate concentration and the dissolved resin concentration in the developer are measured, and the CD value obtained by developing is a constant value. A method for adjusting the concentration of a developing solution, characterized in that the alkali concentration is adjusted based on a previously prepared relationship between an alkali concentration, a carbonate concentration, and a dissolved resin concentration capable of exhibiting dissolving ability. 8. The method for adjusting the concentration of a developer according to claim 7, wherein the alkali component of the developer is tetramethylammonium hydroxide, and the relationship between the alkali concentration, the carbonate concentration, and the dissolved resin concentration prepared in advance is expressed by the following approximation formula: y = (2.33 x 10 ^-6 x ² + 6.36 x 10 ^-4 x + 0.36c) /8.79 + 2.38 Where x is the carbonate concentration (ppm), c is the dissolved resin concentration (abs), and y is the TMAH concentration (% by weight). The method according to claim 7 or 8, wherein the ultrasonic wave propagation rate, the electron conductivity of the developer and the absorbance of the developer are measured as a concentration meter in measuring the alkali concentration of the developer, the carbonate concentration in the developer, and the dissolved resin concentration. Developer using a multi-component concentration meter capable of detecting alkali concentration of developer, carbonate concentration in developer and dissolved resin concentration on the basis of the relationship between ultrasonic propagation rate, electron conductivity and absorbance at temperature, alkali concentration, carbonate concentration and dissolved resin concentration How to adjust the concentration of. A manufacturing apparatus for producing an alkaline developer used for developing a photoresist, comprising: a manufacturing tank for producing a developer having a predetermined concentration, a supply line for supplying the manufactured developer to a developing process, and a used developer for receiving the used developer in the manufacturing tank; A recovery line, a stock solution supply line for supplying a new developer stock solution having a higher concentration than the reference concentration to the production tank, an alkali concentration of the developer in the production tank, a concentration meter for detecting a carbonate concentration and a dissolved resin concentration in the development solution, and a concentration meter A control device for controlling the supply of the developer stock solution from the stock solution supply line on the basis of the detected concentration, the controller comprising an alkali concentration of the developer measured by the densitometer, a carbonate concentration and dissolved resin concentration in the developer, and a development CD value that can be obtained by processing An apparatus for producing a developer, characterized in that it has a function of controlling supply of a developer stock solution based on a pre-created relationship between an alkali concentration, a carbonate concentration, and a dissolved resin concentration capable of exhibiting solubility. The manufacturing apparatus of the developing solution of Claim 10 whose alkali component of a developing solution is tetramethylammonium hydroxide, and the relationship between the alkali concentration, carbonate concentration, and dissolved resin concentration which were prepared previously is represented by the following approximation formula: y = (2.33 x 10 ^-6 x ² + 6.36 x 10 ^-4 x + 0.36c) /8.79 + 2.38 Where x is the carbonate concentration (ppm), c is the dissolved resin concentration (abs), and y is the TMAH concentration (% by weight). 12. The concentration meter according to claim 10 or 11, wherein the concentration meter measures the ultrasonic wave propagation rate, the electron conductivity of the developer and the absorbance in the developer, and the ultrasonic wave propagation rate and the electron conductivity at the predetermined temperature, alkali concentration, carbonate concentration and dissolved resin concentration. And a multicomponent concentration meter capable of detecting the alkali concentration of the developer, the carbonate concentration in the developer, and the dissolved resin concentration based on the relationship between the absorbance and the absorbance. Alkali concentration was adjusted by the density | concentration adjustment method of the developing solution in any one of Claims 1-3, 7-9 using the used developing solution collect | recovered from the developing process. The developing solution characterized by the above-mentioned. The developing solution produced using the developing solution of any one of Claims 4-6 and 10-12 using the used developing solution collect | recovered from the image development process.