JPH0354571A - Method for removing photosensitive resin - Google Patents

Abstract

PURPOSE:To prevent the blackening and thinning of a chromium thin film by treating the film with oxygen plasma added with alcohol. CONSTITUTION:Substrates 4 formed with patterns consisting of a photosensitive resin on the chromium thin film of glass substrates are placed on a boat 3 and the boat is put into a reaction chamber 2. After a desired vacuum degree is developed in the chamber and thereafter, the substrates are treated by using the oxygen plasma formed by bubbling gaseous nitrogen in a hermetic vessel 14 and incorporating ethyl alcohol therein. The photosensitive resin is then removed in the state absent of the thinning and blackening of the chromium film.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a method for removing photosensitive resin used in microfabrication, and in particular, proposes a high-speed method for removing photosensitive resin on a thin chromium film. .

Conventional methods for removing photosensitive resin used in selective patterning of various thin film buttons and coatings on substrates include heating immersion in organic solvents, hot sulfuric acid to which hydrogen peroxide has been added, etc. Methods using chemicals, such as immersion in water, immersion in fuming nitric acid, immersion in highly concentrated developer, etc., and methods using gases, such as ashing in oxygen (02) plasma. There is,
It is selected as appropriate depending on the substrate material and photosensitive resin base, or in consideration of physical or chemical damage to the device during fabrication.

Methods that use chemicals require high maintenance costs for securing the large amount of pure water required after treatment and for treating waste liquid, so dry treatment using oxygen plasma has recently become more popular, even though the initial investment is high. This is becoming effective in terms of lowering running costs. Ashing of the photosensitive resin by oxygen plasma is carried out, for example, as shown in the figure, in a quartz reaction chamber 2 to which a rotary pump 1 is connected as a mechanism for maintaining a reduced pressure state. This is achieved by leaving a substrate 4 coated with a photosensitive resin together with a boat 3 formed of aluminum or aluminum, and generating an oxygen plasma state in the reaction chamber 2 with power supplied from a high frequency power source 5. be decapitated. In addition, ρ 6. A is an opening/closing valve for vacuuming, valve 8.9 is an opening/closing valve for oxygen gas, which is the raw material gas, and nitrogen (N2) gas for purging, and 1o is a lid for taking port 3 in and out. , O-ring, etc. are used in combination to maintain the vacuum. Reference numeral 11 denotes an electrode for capacitive coupling installed on the outer wall of the quartz container 2.

Generally, in order to increase the ashing rate by oxygen plasma, two methods are effective: increasing the temperature of the substrate to accelerate the decomposition of the photosensitive resin, and increasing high-frequency power to supply a large amount of oxygen plasma. If the container 2 is made of quartz, the substrate can be easily heated and heated from the outside using a heating means such as an infrared lamp.

Problems to be Solved by the Invention Photomasks have long been used industrially to selectively shape chromium (-Or) thin films on glass substrates. Moreover, the well-known photomask has a high added value, and even if it takes a long time to process, there is no problem with productivity. However, in recent years, active type liquid crystal display devices, which require a thin chromium film on a glass substrate, have suddenly attracted attention.

For active substrates that make up liquid crystal panels, productivity equivalent to or higher than that of conventional silicon-based semiconductor substrates is required due to cost considerations. It is no longer acceptable to process photopolymer on chrome for 6-10 minutes.

The present inventors attempted to remove the photosensitive resin on the chromium by heating the substrate and increasing the applied high-frequency power in the same manner as in the conventional removal of the photosensitive resin.

As a result, it was found that 1) the surface of the chromium thin film turned black as Crux even in the absence of the photosensitive resin; 2) When a photosensitive resin coexists, the chromium thin film is etched as Or Cox and the film is reduced. There are two points. It can be understood that if an attempt is made to avoid these side effects, the temperature rise of the substrate will be suppressed, and for that reason, the high frequency power will also be lowered, resulting in a decrease in productivity. This method was developed in view of the above, and is intended to prevent deterioration and thinning of the chromium thin film by adding hydrocarbon gas 1 or steam during the oxygen plasma treatment of the chromium thin film.

The hydrocarbon gas or vapor mixed into the working material gas is decomposed by high frequency power and releases a large amount of ap group radicals. On the other hand, ketone groups are generated from the photosensitive resin decomposed by oxygen plasma, and as a result, the ketone groups immediately react with the apkyl groups and are lost as etheroles, which suppresses the bonding between chromium and ketone groups and causes the reaction. It is thought that CrCOx, which is a sex product, is no longer produced. In addition, after the removal of the photosensitive resin is completed, the radicals of the alkylene group continue to react with the oxygen plasma, so it is thought that the direct reaction between the oxygen plasma and chromium is suppressed, resulting in the production of Crux. It will be done.

EXAMPLE A method for removing a photosensitive resin according to an example of the present invention will be described below.

The reaction chamber was a cylindrical quartz container with an inner diameter of 360 ff and a length of about 100 ft., and a glass substrate with a thickness of 1.1 ff and a chromium thin film with a thickness of 1 μm was deposited on a chromium thin film of about 48 pieces each by a ceramic plate. This article describes the results of plasma treatment on a boat.

As the photosensitive resin, NNR-747 manufactured by Nagase Sangyo Co., Ltd. was applied to a film thickness of 1 μm, and the pattern occupancy rate on the substrate after exposure and development was 60 Yus. 13.56M} 12.800 watts of high-frequency power is supplied via capacitive coupling from the outer wall of the quartz container, and under the processing conditions of a vacuum degree of 0.7 Torr, an oxygen gas flow rate of 1008 CCM, and a substrate heating temperature of 200 degrees Celsius, the exposure on bare glass can be achieved in 46 minutes. The plastic resin could be removed. Under these conditions, it depends to some extent on the surface condition of the chromium, that is, whether or not a thin oxide film is formed on the surface due to passivation.
When the removal of the photosensitive resin is completed, partial disappearance and blackening of the chromium thin film is observed. Therefore, as indicated by the dotted line 12 in the figure, nitrogen (N2) gas was introduced into the airtight container 14 containing the alcohol solution 13 at 1o using the open/close valves 15 and 16.
When a hydrocarbon gas obtained by bubbling an ethyl alcohol (C2H501{) liquid as a carrier gas was introduced into the reaction chamber 2 at a flow rate of osccM, it took 60 minutes to remove the photosensitive resin. However, no thinning or blackening of the chromium film occurred. The removal speed of the photosensitive resin is different from that of etepanorekonore (C2H50H) and Nimethylrea! Equivalent results can be obtained by using an anole recorder such as recorder (OH, OH) or fluorophore recorder (05M, OHI).

Effects of the Invention According to the present invention, the photosensitive resin on the chromium thin film can be removed by oxygen plasma without film loss or blackening, although the processing time is somewhat longer, and it is possible to remove the photosensitive resin on the chromium thin film using oxygen plasma without reducing the film or blackening. Compared to its counterpart, processing time is significantly reduced from shame to child;
Its industrial value is extremely high.

[Brief explanation of drawings]

The figure is a system diagram of a photosensitive resin ashing device using oxygen plasma. 1...Vacuum pump, 2...Reaction chamber, 3...
...Boat, 4...Board, 5...
High frequency power supply, 6, 7, 8, 9, 15.16...
Opening/closing vanolep, 10... Lid, 1 1 1... High frequency electrode, 4... Airtight container.

Claims (1)

[Claims] A method for removing photosensitive resin, which comprises adding hydrocarbon gas or steam such as alcohol to oxygen plasma under reduced pressure in a reaction chamber during oxygen plasma treatment of a thin chromium film.