JPH1184679A - Continuous development method of photosensitive resin and development initiator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a development method for a photosensitive resin which keeps the specified performance of a developer right after vatting and makes it possible to obtain substrates having stable quality from the start of the operation of a development device in a development method for the photosensitive resin using an aq. alkaline soln. as the developer and a development initiator. SOLUTION: Development is executed in this continuous development method for the photosensitive resin at the time of developing the exposed photosensitive resin by the aq. alkaline soln., by dissolving the photosensitive resin into the developer at the time of vatting, detecting the concn. of the photosensitive resin in the developer by a spectrophotometer under continuation of the development, discharging the developer when the concn. of the photosensitive resin in the developer exceeds a regulated value, detecting the liquid level of the developer by a liquid level gage, detecting the alkali concn. of the developer by an electrical conductivity meter and replenishing the stock developer and pure water in such a manner that the amt. of the developer and the alkali concn. maintain regulated values, thereby maintaining the concn. of the photosensitive resin and alkali concn. in the developer always constant. The development initiator contg. the positive type photosensitive resin made alkali soluble is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for continuously developing a photosensitive resin and a development initiator. More specifically, the present invention relates to a continuous development method and a development initiator for a positive photosensitive resin capable of obtaining a line width and a residual film ratio after development that are more stable immediately after the bathing.

[0002]

2. Description of the Related Art A photosensitive resin containing a compound having a quinonediazide group changes from alkali-insoluble to alkali-soluble when the quinonediazide group is decomposed by light irradiation to form a carboxyl group. Therefore, if the substrate coated with the photosensitive resin is exposed to light and then developed with an aqueous alkali solution, the photosensitive resin in a portion irradiated with light can be removed, and the photosensitive resin can be used as a positive photosensitive resin. Can be. Positive photosensitive resins have been widely used because of their remarkably excellent resolution. In semiconductor manufacturing processes using positive photosensitive resin, liquid crystal substrate manufacturing processes, printed circuit board manufacturing processes, etc.,
As a developing solution of the photosensitive resin, an aqueous solution of an organic alkali such as an aqueous solution of tetramethylammonium hydroxide or choline, or an aqueous solution of an inorganic alkali such as an aqueous solution of potassium hydroxide, an aqueous solution of sodium carbonate, or an aqueous solution of sodium metasilicate is sprayed or used. Used in dip systems. When the positive-type photosensitive resin is developed with such an alkaline aqueous solution, the positive-type photosensitive resin that has become alkali-soluble by exposure is eluted into the developer, and in the batch operation, the eluted photosensitive resin is contained in the developer. And the accumulated amount increases as the number of processed substrates increases. As the concentration of the photosensitive resin in the developer increases, the residual film ratio on the substrate decreases. The residual film ratio is the ratio of the thickness of the photosensitive resin after development (TAD) to the thickness of the photosensitive resin before development (TBD). Residual film ratio (%) = (TAD / TBD) × 100 Is the value represented by FIG. 1 is a diagram showing an example of the relationship between the number of processed substrates, the photosensitive resin concentration in a developer, and the remaining film ratio in a conventional developing method. In this figure, the horizontal axis indicates the number of processed substrates, the left vertical axis indicates the absorbance of the developer at 450 nm, and the right vertical axis indicates the residual film ratio of the substrate. 450 of developer
The absorbance at nm is a value proportional to the concentration of the photosensitive resin in the developer. According to the conventional developing method, the remaining film ratio decreases with the number of processed substrates as shown in this figure, so that the quality of the developed substrate is not stable and the developer is completely replaced when a certain number of processed substrates is reached. A need arises. A continuous development method that can always keep the quality of the developed substrate constant has been studied. For example, JP-A-5-40
No. 345 discloses a developing solution discharging means for detecting the concentration of a dissolved resin in a developing solution by an absorptiometer and discharging the developing solution, and a developing solution level and a pure water by detecting the level of the developing solution by a level meter. And a second replenishing means for detecting the alkali concentration of the developer with a conductivity meter and replenishing the undiluted developing solution or pure water to thereby constantly maintain the developing performance of the developing solution. A developing solution management device has been proposed. FIG. 2 is a diagram showing an example of the relationship between the number of processed substrates, the photosensitive resin concentration in the developer, and the remaining film ratio when such a developer management device is used. In this figure, when the number of processed substrates exceeds 400, the concentration of the photosensitive resin in the developing solution becomes substantially constant, and the residual film ratio of the substrate becomes substantially constant accordingly. , The concentration of the photosensitive resin in the developer gradually increases, and the residual film ratio of the substrate changes accordingly. For this reason, there has been a demand for a method of continuously developing a photosensitive resin which has a constant developing performance immediately after bathing of a developing solution and can always perform stable development.

[0003]

SUMMARY OF THE INVENTION The present invention relates to a method for continuously developing a photosensitive resin using an aqueous alkali solution as a developing solution, in which the developing performance is constant immediately after the bathing of the developing solution and more stable than when the operation of the developing device is started. To develop,
An object of the present invention is to provide a method for continuously developing a photosensitive resin capable of obtaining a substrate of constant quality and a development initiator used for the method.

[0004]

Means for Solving the Problems The inventors of the present invention have made intensive studies to solve the above-mentioned problems, and as a result, have found that a developing solution at the time of building a bath contains an alkali-soluble photosensitive resin. As a result, it has been found that the residual film ratio of the substrate can be made constant immediately after the start of the operation of the developing device, and the present invention has been completed based on this finding. That is, according to the present invention, (1) when developing the exposed photosensitive resin with an alkaline aqueous solution, the photosensitive resin is dissolved in the developing solution at the time of building bath, and the photosensitive resin in the developing solution is continuously developed. The resin concentration is detected by a spectrophotometer, and when the concentration of the photosensitive resin in the developer exceeds a specified value, the developer is discharged.The liquid level of the developer is detected by a liquid level meter, and the alkali of the developer is detected. By detecting the concentration with a conductivity meter and replenishing the undiluted developing solution and pure water so that the amount of the developing solution and the alkali concentration maintain the specified values, the concentration of the photosensitive resin and the alkali concentration in the developing solution are constantly maintained. (2) The method according to (1), wherein the development is performed while keeping the development temperature constant. Continuous development method of resin, (3) developer for bathing The concentration of the photosensitive resin in the substantially equal first to the concentration of the photosensitive resin in the developing solution at the time constant (1) or
(2) The method for continuous development of the photosensitive resin described in (2), and (4)
A development initiator characterized by containing an alkali-soluble positive photosensitive resin.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The photosensitive resin used in the method of the present invention can be used without any particular limitation as long as it becomes soluble in an aqueous alkali solution upon exposure. For example, a photosensitive resin using a cresol novolak resin as a resin component and an ester of o-naphthoquinonediazidesulfonic acid and polyhydroxybenzophenone as a sensitizer can be used. As the developer used in the method of the present invention,
Any alkaline aqueous solution capable of dissolving and removing the exposed photosensitive resin can be used without particular limitation. Examples of such an alkaline aqueous solution include potassium hydroxide, sodium hydroxide, sodium phosphate, and sodium silicate. And inorganic alkali aqueous solutions composed of a single or a mixture of inorganic alkalis, and organic alkaline aqueous solutions composed of a single or a mixture of organic alkalis such as tetramethylammonium hydroxide and choline.

In the method of the present invention, the exposed liquid crystal substrate, printed circuit board and the like are developed with an alkaline developer in a developing step. In the method of the present invention, the photosensitive resin is dissolved in the developing solution at the time of bathing. The photosensitive resin is preferably the same as that applied on the substrate to be developed, and more preferably a positive photosensitive resin in which the photosensitive resin becomes alkali-soluble by exposure. It is preferable that the concentration of the photosensitive resin in the developer during the bathing is substantially equal to the concentration of the photosensitive resin in the developer during the steady state. When the concentration of the photosensitive resin in the developing solution at the time of bathing is substantially equal to the concentration of the photosensitive resin in the developing solution at the steady state, the concentration of the photosensitive resin in the developing solution is constant. 0.8 to less than the concentration of the photosensitive resin in the developer at all times
It means that it is 1.2 times. The concentration of the photosensitive resin in the developer can be determined by measuring the absorbance of the developer at a specific wavelength using a spectrophotometer. The wavelength for measuring the absorbance can be arbitrarily selected according to the photosensitive resin, and for example, a wavelength of 450 nm can be suitably used. The concentration of the photosensitive resin in the developer at a constant time is estimated by determining the operating conditions of the developing device in advance, estimated by conducting preliminary experiments, or assumed based on past operation results. be able to.

In the method of the present invention, a development initiator is prepared in advance in order to dissolve the photosensitive resin in the developing solution at the time of bathing. The development initiator is an aqueous solution of an alkali-soluble positive photosensitive resin, and can be made alkali-soluble by, for example, exposing the positive photosensitive resin to light. The concentration of the photosensitive resin in the development initiator is not particularly limited and can be arbitrarily selected. For example, the concentration of the photosensitive resin in the development initiator can be determined by changing the concentration of the photosensitive resin in the developing solution at a steady state. 2 to 100 times the concentration of In the method of the present invention, the developing solution is bathed by mixing the undiluted developing solution, the development initiator and the pure water. What is a developing solution?
An aqueous solution containing a high concentration of alkali, for example, 20% by weight of tetramethylammonium hydroxide.
An aqueous solution can be used. By mixing the undiluted developing solution, the development initiator and the pure water, a developing solution containing an alkali and a photosensitive resin substantially equal to the alkali concentration and the photosensitive resin concentration in the developing solution in a steady state is built up. . In the method of the present invention, after the development is started using the bathed developing solution, the concentration of the photosensitive resin, the alkali concentration and the amount of the solution in the developing solution are continuously measured, and the concentration of the photosensitive resin in the developing solution is measured. If the value exceeds the specified value, the developing solution is discharged, and the developing solution and pure water are replenished so as to maintain the specified alkali concentration and liquid amount. According to the method of the present invention, the photosensitive resin concentration and the alkali concentration in the developing solution are kept constant and do not fluctuate immediately after the start of the operation of the developing device. Substrate can be obtained.

[0008]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention. Example 1 As a developing solution, a 20% by weight aqueous solution of tetramethylammonium hydroxide was prepared. The quinonediazide-based positive photosensitive resin was exposed to alkali to make it soluble in alkali, dissolved in a 20% by weight aqueous solution of tetramethylammonium hydroxide, and the 10-fold diluted solution had an absorbance of 1.20 measured at 450 nm. Was prepared. FIG. 3 is a system diagram of the developing device used in the present embodiment. The substrate 6 is moved by the roller conveyor 5 in the developing tank 1 provided with the developing chamber hood 4, and the substrate is developed by spraying a developing solution onto the substrate from a developing solution spray 7. In the development processing tank, a pump 8 for feeding a developer spray, a filter 9 for removing fine particles and the like in the developer, a circulation pump 11 for cleaning and stirring the developer, a filter for removing fine particles 13, spectrophotometer 16, liquid level meter 3, conductivity meter 15, overflow tank 2, developer discharge pump 18, developing solution supply can 1
9, a flow control valve 21 for supplying a developing solution and a flow control valve 22 for supplying pure water. The amount of the developer in the developing tank was 100 liters. Development initiator 1
0.0 liter, 1.9 liter undiluted solution and 88.00 pure water
By mixing 1 liter, the developing solution was bathed in the developing tank. The quinone azide-based positive photosensitive resin was applied, and the exposed substrate was developed using this developing apparatus. Each time 200 substrates were processed, the absorbance of the developing solution at 450 nm and the residual film ratio of the substrate were measured. FIG. 4 is a diagram showing the relationship between the number of processed substrates, the concentration of the photosensitive resin in the developer, and the remaining film ratio in this embodiment. From this figure, it can be seen that according to the continuous developing method of the present invention, the concentration of the photosensitive resin in the developer is constant immediately after the start of the development, and the residual film ratio of the developed substrate is also constant from the beginning.

[0009]

According to the method of the present invention, by using a development initiator, it is possible to start the operation of a developing apparatus using a developing solution in which a photosensitive resin substantially equal to the concentration at a steady state is dissolved. As a result, it is possible to obtain a substrate developed to a certain quality from the beginning of the operation.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of the relationship between the number of processed substrates, the concentration of a photosensitive resin in a developing solution, and the remaining film ratio in a conventional developing method.

FIG. 2 is a diagram illustrating an example of a relationship between the number of processed substrates and the concentration of a photosensitive resin in a developer and a remaining film ratio when a developer management device is used;

FIG. 3 is a system diagram of a developing device used in the embodiment.

FIG. 4 is a diagram showing the relationship between the number of processed substrates, the concentration of a photosensitive resin in a developing solution, and the remaining film ratio in an example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Development processing tank 2 Overflow tank 3 Liquid level meter 4 Developing room hood 5 Roller conveyor 6 Substrate 7 Developing solution spray 8 Liquid sending pump 9 Filter 11 Circulation pump 13 Fine particle removal filter 15 Conductivity meter 16 Spectrophotometer 18 Development Liquid discharge pump 19 Undeveloped solution supply can 21 Flow rate control valve for supplying undeveloped solution 22 Flow rate control valve for supplying pure water

Claims (4)

[Claims] In developing an exposed photosensitive resin with an aqueous alkali solution, the photosensitive resin is dissolved in a developing solution at the time of building bath, and the concentration of the photosensitive resin in the developing solution is reduced while continuing the development. If the concentration of the photosensitive resin in the developing solution exceeds a specified value, the developing solution is discharged, the level of the developing solution is detected by a liquid level meter, and the alkali concentration of the developing solution is detected by a spectrophotometer. The concentration of the photosensitive resin in the developing solution and the alkali concentration are always kept constant by replenishing the developing solution and pure water so that the amount of the developing solution and the alkali concentration are maintained at specified values. A method for continuously developing a photosensitive resin, which comprises developing. 2. The continuous developing method for a photosensitive resin according to claim 1, wherein the photosensitive resin is a positive photosensitive resin which has become alkali-soluble by exposure. 3. The photosensitive resin according to claim 1, wherein the concentration of the photosensitive resin in the developing solution at the time of bathing is substantially equal to the concentration of the photosensitive resin in the developing solution at a steady state. Continuous development method. 4. A development initiator comprising a positive photosensitive resin which has become alkali-soluble.