JPS63178843A - Treatment of photosensitive coating liquid - Google Patents

Abstract

PURPOSE:To extinguish and dissolve air bubble contained into the titled liq. by introducing the titled liq., from which the dissolved oxygen is removed, to a retention part and prolong retention time in the retention part while pressurizing the titled coating liq. in the retention part. CONSTITUTION:The photosensitive coating liq. 33a is supplied from a liq. inlet 8a, introduced to an inlet 9a of tube, arrives at an outlet 9b of module 9 and the dissolved oxygen contained in the liq. 33a is deaerated while the liq. passes through each tube. The dissolved air, which is deaerated while the liq. passes through the module 9, reduces the degree of vacuum of the pressure reducing chamber 10. But at that time, the pressure of the pressure reducing chamber 10 is kept at the desired degree of vacuum by detecting the degree of vacuum with a pressure sensor 13 and actuating a vacuum pump 12 with a control circuit 14. The blister generation after forming of the film is prevented by the obtained photosensitive coating liq. with the dissolved air deaerated.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method for treating a photosensitive coating liquid in order to improve the coating quality when the coating liquid is applied by a coating device. The present invention relates to a method for treating a photosensitive coating liquid for removing dissolved air and bubbles contained in the coating liquid before the coating liquid is applied.

[Prior Art] Generally, when applying certain liquids, it is necessary to remove air dissolved in the liquid and air bubbles contained therein. For example, when a photosensitive coating liquid for photosensitive materials is applied to a substrate by a coating device while containing dissolved air and air bubbles, depending on the coating device, the dissolved air in the photosensitive coating solution may precipitate, or in normal cases. In this case, bubbles contained in the photosensitive coating solution cause defects such as vertical streaks and pinholes on the coated surface, making it impossible to form a uniform photosensitive film on the substrate. It is necessary to remove dissolved air and air bubbles contained in the photosensitive coating solution.

Conventionally, there are many known methods to deal with this problem, first of all removing the air dissolved in the liquid (referred to as deaeration), but a typical example is a method of placing the liquid under reduced pressure. An example of this is the Special Publication No. 51-3525
No. 9, JP-A-56-147605, JP-A-56-76
No. 213, JP-A-49-97003, JP-A-50-1
Devices disclosed in publications such as No. 59469 are known.

There is also a method using a porous polymer membrane, examples of which include JP-A-51-28261 and JP-A-54-123.
No. 785, JP-A-55-121806, JP-A-57-
Methods and devices disclosed in publications such as No. 165007 and Japanese Unexamined Patent Publication No. 58-81404 1 are known.

On the other hand, removing air bubbles contained in the liquid (called defoaming)
Many methods are known. Conventionally, when using a photosensitive coating liquid as a device for performing such defoaming treatment,
Special Publication No. 4.7-6835.

JP 57-6365, JP 53-139274, JP 59-69108, JP 59-92!00
No. 3, JP-A-59-156405.

2. Description of the Related Art Ultrasonic defoaming (referred to as ultrasonic processing) apparatuses are known, which are disclosed in publications such as Japanese Patent Application Laid-Open No. 61-50608.

[Problem that the invention seeks to solve]

However, although the former degassing method can remove air dissolved in the liquid, a phenomenon occurs in which fine bubbles are generated in the liquid. Furthermore, although these methods and devices can remove air dissolved in the liquid, it is extremely difficult to remove air bubbles. Therefore, the microbubbles generated as described above, the bubbles formed by their merging, and the bubbles contained in the liquid are applied to the substrate by a coating device, for example, when a photosensitive coating liquid is used. Then, a problem arises in that a uniform photoresist film cannot be formed.

Furthermore, although the latter defoaming method can remove air bubbles contained in the photosensitive coating liquid, it cannot remove air dissolved in the liquid. Since the air dissolved in the defoamed photosensitive coating liquid is saturated or supersaturated, for example, when the temperature of the photosensitive coating liquid increases or shearing force is applied, the dissolved air precipitates out. However, when it is coated on a substrate, problems occur due to bubbles, making it impossible to form a uniform photoresist film.

The present invention has been made based on the above-mentioned circumstances, and its object is to prevent the generation of air bubbles from dissolved air and bubbles contained in the coating liquid in a method of applying a photosensitive coating liquid to a substrate using a coating device. It is an object of the present invention to provide a method for treating the photosensitive coating liquid in order to prevent coating failure and form a uniform photosensitive film on a substrate.

[Means and effects for solving the problems] The object of the present invention is to perform a treatment to remove dissolved air in the prepared photosensitive coating liquid before applying it to a substrate using a coating device. Then, by increasing the residence time in the retention section while applying pressure to the coating liquid in the retention section,
This is achieved by a method for processing a photosensitive coating liquid, which is characterized by dissolving bubbles contained in the coating liquid (hereinafter referred to as defoaming treatment).

That is, the present invention is the first to apply a photosensitive coating solution to a substrate by sequentially conducting two processing steps, one for removing dissolved air and the other for removing air bubbles by applying pressure, before applying the photosensitive coating solution. In this case, it is possible to obtain a uniform photoresist film that satisfies the essential functions of a photosensitive material, which was previously unanticipated.

The greatest feature of the present invention is that a unique effect has been found by sequentially combining degassing treatment and defoaming treatment, which tend to cause coating defects such as vertical streaks and pinholes when used alone. There is.

This processing method will be described in detail below.

It is essential that the photosensitive coating liquid prepared in the present invention is first subjected to a deaeration treatment and then subjected to a defoaming treatment.

Even if the degassing step is continuously combined after the defoaming treatment step, the above-mentioned unique effect is not observed.

Any method may be used for the degassing step of the present invention, but in the case of a photosensitive coating liquid, the degassing step is usually 300 Torr to 1 Torr.
It is preferable to carry out the process under a pressure of about rr.

Note that the photosensitive coating liquid may be continuously deaerated, or the pressure may be reduced for each photosensitive coating liquid tank. However, when a photosensitive coating liquid is continuously applied to a substrate using a coating device, it is preferable to lead it to a continuous degassing step.Moreover, when using an organic solvent, a degassing method that hardly causes evaporation is preferable. desirable. Furthermore, as an apparatus for performing deaeration treatment, one having a simple structure is preferable in terms of equipment cost, stability during long-term operation, maintainability, running cost, etc.

Such methods and devices include degassing devices using porous polymer membranes.

Generally, a deaerator A using a tube made of a porous polymer membrane has a decompression chamber 2 containing a spiral tube 1 made of a porous polymer membrane and a vacuum degree as shown in FIG. It is constituted by a pressure sensor 5 which detects the pressure and activates or stops the vacuum pump 4 which lowers the pressure in the decompression chamber 2 via the control circuit 3.

When removing gas dissolved in the liquid 6 or the like using the degassing device A, the decompression chamber 2 is passed through the porous polymer membrane spiral tube at a predetermined speed using the pump 7. JP-A-59-216606 and JP-A-60 are methods for increasing the throughput while degassing desired dissolved air from the liquid.
Publication No. 25514 discloses that the material, inner diameter and wall thickness of the tube are determined, the length per tube that satisfies the desired amount of dissolved air degassing and throughput is determined, and multiple tubes are arranged in parallel. A method for determining the number of tubes needed to make a tube module is described.

In the defoaming process of the present invention, pressure is applied to the degassed liquid, so in the case of a photosensitive coating liquid, the defoaming process may be carried out continuously or all at once. It may take the form of processing. However, when applying the photosensitive coating liquid to a continuously moving substrate using a coating device, it is preferable to continuously lead the photosensitive coating liquid to a defoaming treatment step.

Such a defoaming treatment device has a structure that can pressurize the photosensitive coating liquid, and has a residence that can secure the necessary time for microbubbles or bubbles in the photosensitive coating liquid to melt and disappear under pressure. It is desirable that the retention section has a temperature control device capable of controlling the temperature of the photosensitive coating liquid therein, and is further provided with a filter for filtration.

There is a close relationship between defoaming ability by pressurization and residence time, and although it depends on the degree of pressurization, appropriate defoaming can be achieved when the residence time is within a certain range, for example, 2 minutes or more.

If the residence time is long, the microbubbles or air bubbles will be completely melted and eliminated, but the volume of the residence will become large and the device will not be effective.

If the residence time is short, such as 2 minutes or less, the microbubbles or air bubbles may not be completely dissolved and may flow out as they are.

In either case, the amount of dissolved air in the degassed liquid,
The degree of pressurization and residence time are closely related to each other. However, the degree of pressurization is naturally limited due to the capacity of the pressurizing means, the pressure resistance of the defoaming device, manufacturing costs, operational safety, etc., and in the case of photosensitive coating liquids, it is generally 0.5 kg/c+a. Above 5
The pressure should be lower than kg/crA gauge pressure.

In addition, by installing a filtration filter in the retention area and creating a structure in which microbubbles or air bubbles are trapped in the filter, it is possible to prevent the microbubbles or air bubbles from flowing out, and to create a retention area with a short retention time. I can do it.

The trapped microbubbles or bubbles are melted and eliminated by the degassed liquid to be degassed, which has the ability to melt and absorb bubbles and the like under pressure.

Further, by lowering the temperature of the liquid to be defoamed in the retention section to be lower than the temperature of the liquid when it is degassed, the defoaming ability can be improved. This can be understood from the fact that the amount of air dissolved in the liquid is greater when the liquid temperature is lower. Generally, when using a photosensitive coating liquid, it is desirable that the liquid temperature during defoaming be 2° C. or more lower than the liquid temperature during degassing.

The prepared photosensitive coating liquid is first subjected to a deaeration process using the above-mentioned deaerator or the like to remove air dissolved in the liquid. The photosensitive coating liquid thus deaerated is in a state where it absorbs air and is easily melted. Therefore, the more air dissolved in the photosensitive coating liquid is removed, the higher the ability of the photosensitive coating liquid to absorb and dissolve air becomes. The amount of dissolved air to be degassed depends on the amount of air bubbles to be degassed in the next defoaming process, the composition of the photosensitive coating liquid, and the time when the coating is applied to a continuously moving substrate by the coating device. It is determined by the shape of the photoresist film, etc. In the degassing method in which the photosensitive coating liquid is placed under reduced pressure or in the degassing method using a porous polymer membrane tube, the coating liquid is certainly degassed, but as mentioned above, the former In the latter case, microbubbles are generated, and in the latter case, the air bubbles that have flowed in before being deaerated cannot be removed.As a result, both methods cannot remove the microbubbles or air bubbles.

However, since the degassed liquid of the photosensitive coating liquid containing such microbubbles or air bubbles has the ability to absorb and dissolve air, it is necessary to pressurize the degassed liquid to increase the residence time as described above. This makes it extremely easy to eliminate microbubbles or air bubbles.

Furthermore, by increasing the amount of air removed in the degassing step so that the dissolved air in the degassing liquid does not become saturated even if the microbubbles or bubbles contained in the degassing liquid disappear by pressurization. It is possible to prevent the precipitation of dissolved air due to a drop in the liquid temperature of the photosensitive coating liquid and shearing force, and as a result, when such a photosensitive coating liquid is applied to a substrate, there will be no vertical streaks, pinholes, blisters, etc. Since the occurrence of the above defects can be prevented, a uniform photoresist film can be obtained.

Next, the present invention will be explained based on the deaerator shown in FIG. 2 and the deaerator shown in FIG.

First, the deaerator 8 shown in FIG. 2 is a module 9 formed of a large number of tubes made of porous polymer membranes. Decompression chamber 1
0. Photosensitive coating liquid inlet 8a outlet Bb, exhaust pipe 11. Vacuum pump 12. The module 9 is composed of a pressure sensor 13 and a control circuit 14, and is housed in a decompression chamber 10.

The inlet and outlet of the tube are 9a and 9b are the inlet and outlet of the liquid respectively.
It opens at a and 8b. The decompression chamber 10 is a vacuum pump 1
2 through piping 11, and is maintained at a desired degree of vacuum by pressure sensor 13 and control circuit 14.

The photosensitive coating liquid 33a is supplied from the liquid inlet 8a and guided to the tube inlet 9a, and while passing through each tube, the dissolved air in the photosensitive coating liquid 33a is degassed, and the photosensitive coating liquid 33a is removed from the outlet of the module 9. 9b, and becomes a deaerated photosensitive coating liquid 33b. The dissolved air degassed while passing through the module 9 lowers the degree of vacuum in the decompression chamber 10, but at this time the pressure sensor 13 detects the degree of vacuum and the control circuit 1
4, the vacuum pump 12 is operated to maintain the decompression chamber 10 at a desired degree of vacuum.

The porous polymer membrane tube forming the module 9 is made of polytetrafluoroethylene resin, and has an inner diameter of 1.8 mm and a wall thickness of 0.2 mm.

Next, FIG. 3 shows a typical defoaming device for carrying out this invention. Reference numeral 15 denotes a defoaming device, which has an inlet 17a for the deaerated photosensitive coating liquid 33b in the upper part and an outlet 17b in the lower part in the circular or polygonal tube 16 which holds the tube axis in the vertical direction. A liquid guide pipe 18 is provided, and the liquid guide pipe 18
The volume is large at the central portion 18a.

A gap 19 between the liquid guide pipe 18 and the pipe body 16 is filled with @prepared liquid 35 maintained at a constant temperature and pressure. 1
9a is an inlet for the temperature control liquid 35, and 19b is a bath outlet. An air vent valve 20 is provided at the top of the liquid guide pipe 18 when liquid feeding is started, and a pressure valve for applying pressure to the degassed photosensitive coating liquid 33b is provided after the outlet 17b at the bottom. 21 are provided. The liquid conduit 18 is connected after the deaeration device, and the photosensitive coating liquid 33b flowing down the liquid conduit 18 from above is pressurized by the pressure valve 21 and at the center part 18a of the liquid conduit. The flow rate is reduced and the residence time is increased.

Applying pressure to the photosensitive coating liquid 33b and the central portion 18 of the liquid guide pipe
Microbubbles or air bubbles mixed into the photosensitive coating liquid 33b are dissolved into the liquid and disappear due to the residence time at point a.

FIG. 4 shows another form of the defoaming device for carrying out the present invention, and in the figure, 23a and 23b are filters provided in the liquid conduit 18. 2
2 is included.

Similarly to FIG. 3, the photosensitive coating liquid 33b flowing down the liquid guide pipe 18 is pressurized by the pressure valve 21, and its flow rate is reduced in the central part 18a of the liquid guide pipe.
Although the residence time becomes longer, the fine bubbles or air bubbles present in the photosensitive coating liquid 33b are trapped by the filter, so the residence time of the fine bubbles or air bubbles becomes even longer.

The trapped microbubbles or air bubbles are melted and eliminated by pressurization into the deaerated photosensitive coating liquid 33b, which has the ability to melt and absorb bubbles, and become a photosensitive coating liquid 33C.

In FIGS. 3 and 4, the liquid temperature during the defoaming process can be lower than that of the photosensitive coating liquid 33b flowing in from the inlet 17a by controlling the temperature of the temperature control liquid 35. Furthermore, the defoaming efficiency can be increased.

Figure 1 shows the flow of the experimental equipment used to confirm the above effects, and 24 in the figure is the KM'A tank.

25 is a pump, 8 is a deaerator, 15 is a defoaming device, and 30 is a valve. The photosensitive coating liquid 33 is supplied to the defoaming device 15 by a pump 25 through a device 8 consisting of a preparation tank 24 equipped with an agitator 32 . Air is mixed and dispersed using the gas-liquid mixer 34 on the input side of the pump 25, and air is mixed and dispersed between the pump 25 and the deaerator 8.
Bubble detectors 27, 28 and 29 are installed between the degassing device 15 and the output side piping of the defoaming device 15, and a pressurizing valve 21 is installed between the degassing device 15 and the bubble detector 29. 25 and the degassing device 8, a pressure gauge 26 is installed between each, and a bubble detector 28 and the degassing device 1 are installed.
Between 5 and 5, a sampling valve 31 for sampling the photosensitive coating liquid 33b is installed in order to check the degree of degassing by the degassing device 8.

The aim is to evaluate the degassing ability and defoaming ability by 1.

Note that bubble detectors 27, 28, and 29 are manufactured by Japanese Patent Application Laid-Open No. 1985-85.
The material disclosed in Publication No. 44 was made into a pressure-resistant large-scale type and used.

〔Example〕

The embodiments of the present invention will be described below with reference to one specific example, but these examples are not intended to limit the scope of the present invention in any way.

Example 1 Using the experimental apparatus shown in Figure 1, a photosensitive coating liquid ■ and No. 1 were prepared using the experimental apparatus shown in Figure 1.
Table (Photosensitive coating liquid - ■) Table 2 (Photosensitive coating liquid - ■) ■ Specifications and conditions of deaerator a Decompression chamber degree of vacuum Adjust to obtain the desired amount of deaeration.

b Tube material Polytetrafluoroethylene resin Inner diameter 1.81111 Wall thickness 0.2+n ■ Defoaming device specifications and conditions a Inner volume 5Ilb Filter Microwind II 1 ttm (A
(Made by MF CUND) C Temperature adjustment Temperature: Adjust so that the liquid temperature at the outlet is 2℃ lower than the inlet liquid temperature Flow rate: 2β/min dEntrained air bubbles Size: 50 to 300μ Passage of photosensitive coating liquids ■ and H under the above conditions amount.

In addition to changing the pressure applied to the defoaming device, if a filter is installed or if the outlet liquid temperature is lower than the inlet liquid temperature, air bubble detectors are installed between the degassing device and the defoaming device, and on the outlet side of the defoaming device. Table 3 shows the results of comparing the detection signals of . Note that air bubble detectors 2 are installed on the inlet and outlet sides of the deaerator 8.
Since there was almost no difference in the detection signal of 7.28, it was compared with the inlet side of the defoaming device 15.

Furthermore, in order to examine the amount of deaeration of the photosensitive coating liquid degassed by the deaerator, the degassed liquid was sampled from the sampling valve 31 and the dissolved oxygen concentration was measured with a dissolved oxygen concentration meter.

The term "relative dissolved air amount" used to express the amount of deaeration is defined as follows.

A relative dissolved air content of 100% is what is shown when the liquid to be degassed is thoroughly stirred at a certain temperature (20°C in this case), the dissolved air is saturated, and the dissolved oxygen concentration is measured with a dissolved oxygen concentration needle. Regarding the amount of dissolved air in the degassed liquid, the degassed liquid is brought to the same temperature as the liquid containing saturated dissolved air before being degassed (20°C in this case), and the dissolved oxygen concentration is determined in the same way. is measured with a dissolved oxygen concentration meter, and the value at this time is expressed as a relative value to a liquid with a relative dissolved air content of 100%, and is called the relative dissolved air content and is expressed as a percentage. Therefore, it can be said that the smaller the relative dissolved air amount is, the higher the deaeration amount is.

×... There is almost no difference between the incoming detection signal and the outgoing detection signal △... The outgoing detection signal is slightly less than the incoming detection signal ◇... 〃 Considerably less ○... Outgoing detection signal is extremely rare (1 to 100 times/1
0 minutes■...There is no outgoing detection signal. As shown in Table 3, after degassing with the degassing device, air is degassed by pressurizing and retaining the coating liquid in the retaining section. It turns out that it is possible. It can also be seen that installing a filter and lowering the liquid temperature during defoaming are also effective in defoaming.

(Effects of the Invention) As described above, in the method for treating a photosensitive coating liquid according to the present invention, dissolved air in the coating liquid is removed by degassing treatment before the prepared photosensitive coating liquid is introduced into the coating process. Then, by applying pressure to the application liquid and increasing the residence time of the application liquid, microbubbles or air bubbles contained in the application liquid can be dissolved and dissolved in the cough liquid. Therefore, in the actual coating process, the photosensitive coating liquid treated according to the present invention has an enhanced ability to dissolve and absorb bubbles, so there is no precipitation or outflow of bubbles, and there is no blister formation after the formation of the photoresist film. This can be prevented, and the photoresist film thus formed can be made uniform.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram of one embodiment of the experimental apparatus of the present invention, and FIG. 2 is a schematic explanatory diagram of one embodiment of the experimental apparatus of the present invention.
3 is a schematic sectional view of one example of a defoaming device used for dissolving and extinguishing air bubbles of the present invention; FIG. 4 is a schematic sectional view of another example of the defoaming device; FIG. 5 1 is a general schematic explanatory diagram of a deaerator using a tube made of a porous polymer membrane. 8... Deaerator 9... Porous polymer membrane tube module 12...
・Vacuum pump 13...Pressure sensor 14...Control circuit 15...Defoaming device 16...Pipe body 17a...Inflow port 17b...
・Outlet port 18...Liquid guide pipe 19...Gap part 21...Pressure valve 22...Liquid guide pipe 23a, 23
b. -- Filter 24... Liquid preparation tank 25... Pump 26... Pressure gauge 27.28.29... Air bubble detector 31... Sampling valve 32... Stirrer 33.33a, 33b , 33cm... Photosensitive coating liquid 34... Gas-liquid mixing device 35... Temperature control liquid (3 others) Procedural amendment document March 2θ, 1988

Claims (3)

[Claims] (1) Before applying the prepared photosensitive coating liquid to a substrate using a coating device, a treatment is performed to remove dissolved air in the coating liquid, and then the coating liquid is pressurized in a retention area to remove air. A method for processing a photosensitive coating liquid, characterized in that air bubbles contained in the coating liquid are melted and eliminated by increasing the residence time in a retention section. (2) The pressure applied to the coating liquid is 0.5 kg/cm^2
2. The method of processing a photosensitive coating liquid according to claim 1, wherein the pressure is set to be equal to or higher than the gauge pressure, and the residence time of the coating liquid in the retention section is set to 2 minutes or more. (3) A patent claim characterized in that a filter for filtration is installed in the retention part, and the temperature of the photosensitive coating liquid in the retention part is lowered by 2°C or more than during the treatment to remove dissolved air. A method for treating a photosensitive coating liquid according to item 1.