JP2006049713A - Method and apparatus for removing resist - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To remove resist laminated on various grounds surely while shortening the time required for removing the resist even in case of a large area substrate. <P>SOLUTION: The resist removing apparatus D comprises a plasma processing section 10 for lowering adhesion of resist 4 and a substrate 1 by irradiating the resist with fluorine based plasma processing gas under pressure in the vicinity of atmospheric pressure, and a section 20 for stripping and removing the resist 4 from the substrate 1 by supplying water to the resist 4 subjected to lowering adhesion. The removing section for supplying water to the resist comprises a nozzle 23 for blowing pure water to the resist on the substrate, and/or a processing tank for immersing the substrate into pure water. The plasma processing section is provided with a linear opening 16b for blowing out fluorine based plasma gas, and a diffuser 35 for widening the irradiation width of the linear opening. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a resist removal method and a resist removal apparatus for peeling off and removing a resist formed on a surface of a base substrate, a glass substrate or the like in a manufacturing process of a printed circuit board or a liquid crystal display. The present invention relates to a resist removal method and a resist removal apparatus that can reliably remove a resist laminated on a base film.

  In semiconductor manufacturing processes such as LSI and liquid crystal display manufacturing and manufacturing processes of multilayer printed wiring boards and the like, various resists such as photosensitive resins are used for pattern formation depending on the purpose. These resists are removed (peeled) in a step after pattern formation.

    As a resist stripping method, a wet process using a chemical solution or a process using low-pressure plasma is generally employed. In the wet treatment using a chemical solution, a treatment such as washing and drying of the treatment chemical solution is required as a post process. Further, if the drying is insufficient, there is a problem that the remaining chemical causes poor quality.

  In addition, since the process using low-pressure plasma is a decompression process, it takes a lot of time for evacuation, and there is a problem that throughput is poor. Furthermore, when processing a substrate having a large area, a large-capacity vacuum container or a vacuum exhaust device is required, which increases the cost of the device.

Therefore, as a conventional resist stripping technique that does not require a vacuum container or a vacuum exhaust apparatus, there is a resist stripping method and a resist stripping apparatus (Japanese Patent Application No. 2003-030007) according to the application of the present applicant. The technique described in this specification introduces a halogen-based gas that has been made into plasma under a pressure close to atmospheric pressure into an atmosphere having an appropriate humidity to generate an active reaction gas such as hydrofluoric acid (HF), There is a technique for removing the resist by etching the SiO ₂ layer. In this technique, the underlying SiO ₂ layer is etched, a functional group that is hydrolyzed by an active reaction gas is added to the resist, and then the resist is lifted off to lift off the resist.

By the way, in the above-described method of generating plasma in the vicinity of the atmospheric pressure, the underlayer on which the resist is laminated is limited to the SiO ₂ layer, and depending on the underlayer, it cannot be peeled off and removed. The application process is limited in the manufacturing process and the liquid crystal display manufacturing process. In addition, the resist material is limited, and the resist is not applied to a modified resist such as impurity ions doped in a manufacturing process of a semiconductor or a liquid crystal display. Furthermore, the apparatus for generating plasma is in the form of a line, and in order to remove the resist laminated on a large substrate to be processed, it is necessary to move the substrate for processing, which requires a lot of processing time.

  The present invention has been made in view of such problems, and the object of the present invention is to ensure that a variety of resists are laminated on the ground without changing the resist removal process by the ground on which the resist is laminated. It is an object of the present invention to provide a resist removal method and a resist removal apparatus that can be removed in a short time. It is another object of the present invention to provide a resist removal method and a resist removal apparatus that can reduce the time required for resist removal even when the substrate on which the resist is laminated has a large area. It is another object of the present invention to provide a resist removal method and a resist removal apparatus that can reduce damage to the substrate and the base film when removing the resist on the substrate.

The resist removal method according to the present invention is a method of removing a resist laminated on a substrate such as a glass substrate or a printed circuit board, and irradiates the resist by converting the fluorine-based gas into plasma under a pressure near atmospheric pressure. And a step of reducing the adhesion between the resist and the substrate, and a step of supplying moisture to the resist to remove and remove the resist whose adhesion is reduced from the substrate. The fluorine-based gas is preferably a gas containing F atoms such as CF ₄ or C ₂ F ₆ or a mixed gas thereof.

  According to the method for removing a resist according to the present invention configured as described above, for example, if a resist laminated on an aluminum film formed on a substrate is irradiated with a plasma-based fluorine-based gas, F ions are exposed to the resist and the base. Most of them are concentrated at the interface with the aluminum film and hardly exist in the resist. That is, F radicals generated by plasma under a pressure near atmospheric pressure permeate the resist and aggregate at the interface between the resist and the base film, generating a gap between the resist and the base film, and improving the adhesion. It is decreasing. The resist with reduced adhesion can be easily removed from the substrate by a wet process in which moisture is supplied to the resist in the next process, for example. In addition, no damage remains on the substrate or the substrate.

  The supply of moisture to the resist is preferably performed by a process of spraying pure water on the substrate and / or a process of immersing the substrate in pure water. Water can be supplied using tap water such as tap water, but pure water is preferable in consideration of post-treatment. According to this configuration, the adhesion of the resist to the substrate is reduced by the plasma treatment in the previous process, and moisture is supplied by spraying or dipping between the substrate and the resist, and the resist is swollen and easily removed. be able to. The resist is easily removed from the surface of the substrate by the pressure of the sprayed water.

  The resist removal apparatus according to the present invention is an apparatus for removing a resist formed on a substrate such as a glass substrate or a printed board, and irradiates the resist by converting the fluorine-based gas into plasma under a pressure near atmospheric pressure. A plasma processing unit that reduces adhesion between the resist and the substrate, and a removal processing unit that supplies moisture to the resist with reduced adhesion and removes the resist by peeling off the substrate. . The two processes can be performed in succession to efficiently remove the resist.

  The resist removing apparatus of the present invention configured as described above is activated by converting the fluorine-based gas into plasma in the plasma processing unit and spraying and irradiating the resist stacked on the substrate surface. Occurs and adhesion decreases. Next, when moisture is supplied to the resist in the removal processing section, the resist with reduced adhesion can swell and easily peel off from the substrate surface and be removed. In this way, the fluorine-based gas is turned into plasma to reduce the adhesiveness of the resist, and the moisture is supplied and removed, so that even different types of resist can be easily removed. Moreover, even in the case of a base having strong adhesion to the resist, it can be removed reliably, and the processing time in removing the resist after patterning can be shortened.

  In the above resist removal apparatus, the plasma processing unit preferably includes a line-shaped blowout port for blowing out the plasma fluorine-based gas, and preferably includes a diffusion member that widens the irradiation width of the blowout port. With this configuration, the resist laminated on the substrate can be irradiated with a processing gas in a wide width, so that the adhesion force can be reduced in a short time and the wet process for supplying moisture in the next process is performed. The processing time including the resist removal process can be greatly shortened.

Moreover, as a preferable specific aspect of the resist removal apparatus according to the present invention, the removal processing unit includes a nozzle for spraying pure water onto the resist on the substrate and / or a treatment tank for immersing the substrate in pure water. It is characterized by. According to this configuration, the resist whose adhesion has been lowered by the plasma treatment in the previous step is swollen by the moisture sprayed by the nozzle and / or the moisture immersed in and supplied to the treatment tank. The resist floats and can be easily removed. In addition, when the substrate is immersed in pure water and then sprayed with pure water, the resist can be easily removed with the pressure of the sprayed pure water, and a resist removal process can be performed in a short time.

In the present invention, the fluorine-based gas containing F atoms is turned into plasma by discharge plasma treatment under a pressure near atmospheric pressure. Under pressure near atmospheric pressure refers to a pressure condition of 1.333 × 10 ^{4 to} 10.664 × 10 ⁴ Pa (100 to 800 Torr). In particular, the range of 9.331 × 10 ^{4 to} 10.9797 × 10 ⁴ Pa (700 to 780 Torr) is preferable because pressure adjustment is easy and the apparatus configuration is simple.

  In the present invention, as the plasma generating section for converting the fluorine-based gas into plasma, for example, a glow discharge plasma is generated by applying a pulsed electric field between the counter electrodes, and the fluorine-based plasma gas is passed between the counter electrodes. An apparatus etc. can be mentioned.

  Examples of the material of the electrode that generates plasma include simple metals such as iron, copper, and aluminum, alloys such as stainless steel and brass, and intermetallic compounds. The pair of electrodes constituting the counter electrode preferably has a structure in which the distance between the counter electrodes (plasma space) is constant in order to avoid occurrence of arc discharge due to electric field concentration. Specific examples of the electrode structure include a parallel plate type, a roll-plate type, a roll-roll type, and a coaxial cylindrical type.

  It is preferable that a solid dielectric is disposed between the counter electrodes. Specifically, a solid dielectric may be disposed on at least one of the pair of electrodes constituting the counter electrode. At this time, it is preferable that the solid dielectric and the electrode on the side to be installed are in close contact with each other and the opposite surface of the electrode in contact is completely covered. If there is a portion where the electrodes directly face each other without being covered by the solid dielectric, arc discharge is likely to occur therefrom.

  The solid dielectric may be in the form of a sheet or a film. The thickness of the solid dielectric is preferably 0.01 to 4 mm. If the thickness of the solid dielectric is too thick, a high voltage may be required to generate discharge plasma, and if it is too thin, dielectric breakdown may occur during voltage application and arc discharge may occur. The solid dielectric may be a film coated on the electrode surface by a thermal spraying method.

  Examples of the solid dielectric include alumina, plastics such as polytetrafluoroethylene and polyethylene terephthalate, metal oxides such as glass, silicon dioxide, zirconium dioxide, and titanium dioxide, and double oxides such as barium titanate. In addition, various types such as those obtained by multilayering these can be used. In order to avoid an inappropriate discharge such as an arc discharge, it is preferable to round the corner of the electrode member on the center gap side.

  The solid dielectric preferably has a relative dielectric constant of 2 or more (25 ° C. environment, the same applies hereinafter). Specific examples of the solid dielectric having a relative dielectric constant of 2 or more include polytetrafluoroethylene, glass, and metal oxide film. Further, in order to stably generate a high density discharge plasma, it is preferable to use a solid dielectric having a relative dielectric constant of 10 or more. The upper limit of the relative dielectric constant is not particularly limited, but about 18,500 is known as an actual material. Examples of the solid dielectric having a relative dielectric constant of 10 or more include a metal oxide film mixed with 5 to 50% by weight of titanium oxide and 50 to 95% by weight of aluminum oxide, or a metal oxide containing zirconium oxide. The thing which consists of a film can be mentioned.

  The distance between the electrodes of the counter electrode used in the present invention is appropriately determined in consideration of the thickness of the solid dielectric, the magnitude of the applied voltage, the purpose of using plasma, and the like, but is 0.1 to 5 mm. preferable. If the distance between the electrodes is less than 0.1 mm, it may not be sufficient to install the pair of electrodes with a small distance between the electrodes, and the installation work becomes complicated. On the other hand, when it exceeds 5 mm, it is difficult to generate uniform discharge plasma. Furthermore, the preferable distance between electrodes is 0.5-3 mm in which discharge is easy to stabilize.

  An electric field such as a high frequency, a pulse wave, or a microwave is applied between the electrodes of the counter electrode to generate plasma. However, it is preferable to apply a pulse electric field, and in particular, the rise time and / or the fall time of the electric field is 10 μs. The following pulsed electric fields are preferred. If it exceeds 10 μs, the discharge state tends to shift to an arc and becomes unstable, and it becomes difficult to maintain a high-density plasma state by a pulse electric field. Also, the shorter the rise time and fall time, the more efficiently ionization of the gas during plasma generation, but it is actually difficult to realize a pulsed electric field with a rise time of less than 40 ns. A more preferable range of the rise time and the fall time is 50 ns to 5 μs. The rise time here refers to the time during which the voltage (absolute value) continuously increases, and the fall time refers to the time during which the voltage (absolute value) decreases continuously.

  The electric field strength of the pulse electric field is 1-1000 kV / cm, preferably 20-300 kV / cm. If the electric field strength is less than 1 kV / cm, the process takes too much time, and if it exceeds 1000 kV / cm, arc discharge tends to occur.

  The frequency of the pulse electric field is preferably 0.5 kHz or more. If it is less than 0.5 kHz, the plasma density is low, and the process takes too much time. The upper limit is not particularly limited, but it may be a high frequency band such as 13.56 MHz that is commonly used and 500 MHz that is used experimentally. In consideration of ease of matching with the load and handling, 500 kHz or less is preferable. By applying such a pulse electric field, the processing speed can be greatly improved.

  Moreover, it is preferable that one pulse duration in a pulse electric field is 200 microseconds or less, More preferably, it is 3-200 microseconds. If it exceeds 200 μs, it tends to shift to arc discharge. Here, one pulse duration means a continuous ON time of one pulse in a pulse electric field composed of repetition of ON / OFF.

  Note that the voltage applied between the electrodes of the counter electrode is not limited to a pulse voltage, and may be a continuous wave voltage. As the pulse voltage waveform, an appropriate waveform such as a square wave type, a modulation type, or a combination of the above waveforms can be used in addition to the impulse type. Further, the voltage waveform may be a so-called one-wave waveform in which a voltage is applied to either the positive or negative polarity side, in addition to the voltage application repeating positive and negative. A bipolar waveform may also be used. Of course, an AC waveform that is a general sine wave may be used.

  In the present invention, the water supply process (wet process) performed in the removal processing unit includes a process method such as a process of spraying pure water on a resist-laminated substrate, or a process of immersing a resist-laminated substrate in a pure water tank. Can be mentioned. Moreover, it is possible to use tap water or the like instead of pure water. As water used for the wet treatment, ozone water or the like can be used. In that case, as ozone water, for example, ozone generated by an ozone generator is dissolved in water by an ozone dissolution module. The ozone dissolution module preferably contains a gas permeable membrane made of a non-porous membrane. An aqueous solution containing various organic solvents may be used as the cleaning liquid.

  As described above, according to the present invention, the step of reducing the adhesion with the base film by irradiating the resist with a fluorine-based gas that has been converted to plasma under a pressure close to atmospheric pressure, and the adhesion is reduced. A step of supplying moisture to the resist and peeling and removing it from the substrate. After the resist is floated in the first plasma treatment step, the resist is swollen and removed in the second wet treatment step. Even when the adhesive strength is strong, it can be surely removed, and the resist laminated on various bases can be removed. Further, the resist removal process can be performed without damaging the substrate surface.

  Hereinafter, an embodiment of a resist removing apparatus according to the present invention will be described with reference to the drawings. FIG. 1 is a diagram schematically showing the configuration of an embodiment of the resist removal apparatus of the present invention, FIG. 2 is a diagram schematically showing the configuration of the plasma processing unit in FIG. 1, and FIG. 3 is a substrate for performing resist removal processing. FIG.

  A resist removing apparatus D shown in FIGS. 1 and 2 is an apparatus for removing a resist formed on a surface of a substrate 1 after pattern formation. A plasma processing unit 10 for processing the resist on the substrate is peeled off and removed. The removal processing unit 20 and the transfer unit 30 are provided, and the plasma processing unit 10 and the removal processing unit 20 are arranged in parallel. The transport unit 30 is configured to transport the substrate 1 through the plasma processing unit 10 and the removal processing unit 20 and process the substrate 1 in two consecutive steps. As shown in FIG. 3, the substrate 1 from which the resist is removed has a patterned aluminum film 3 formed on the surface of an epoxy substrate (base substrate) 2, for example, and a resist 4 is laminated on the aluminum film as a base film. ing.

  The plasma processing unit 10 includes a plasma processing chamber 11, and an atmospheric gas introduction port 11a is provided in the upper portion of the plasma processing chamber, and an exhaust port 11b is provided in the lower portion. An atmospheric gas supply unit 12 is connected to the atmospheric gas inlet 11a, and the gas atmosphere inside the plasma processing chamber 11 can be arbitrarily set. For example, the atmospheric temperature is 20 ° C. and the humidity is 50% atmospheric (under a pressure near atmospheric pressure). It is possible to maintain the optimum conditions for plasma processing.

  In the plasma processing chamber 11, a plasma generation unit 13 that converts gas into plasma is installed. The plasma generation unit 13 is disposed inside the plasma processing chamber 11 at a position above the substrate 1 on which the resist 4 transferred by the transfer unit 30 is stacked. The plasma generator 13 is constituted by a parallel plate type counter electrode 14 composed of a voltage application electrode 14a and a ground electrode 14b. A power supply 15 is connected to the counter electrode 14.

  The voltage application electrode 14a and the ground electrode 14b of the counter electrode 14 are arranged to face each other so as to be parallel to each other with a predetermined distance (distance between the electrodes) between the voltage application electrode 14a and the ground electrode 14b. A plasma space 16 is formed. Each surface of the voltage application electrode 14a and the ground electrode 14b is covered with a solid dielectric (not shown).

A gas introduction port 16a is provided on one end (upper end) side of the plasma space 16 in the counter electrode 14, and a gas blowing port 16b is provided on the other end (lower end) side. A gas supply unit 17 is connected to the gas inlet 16a via a gas supply line 18, and a fluorine-based gas such as CF ₄ gas is supplied between the voltage application electrode 14a and the ground electrode 14b. it can. Then, by applying an electric field (pulse electric field) from the power supply 15 between the voltage application electrode 14a and the ground electrode 14b in a gas supply state, glow discharge plasma is generated between the voltage application electrode 14a and the ground electrode 14b. The supplied gas is converted into plasma, and the plasma gas is blown downward from the gas blowing port 16b and irradiated onto the resist 4 of the substrate 1.

  The removal processing unit 20 includes a processing chamber 21, in which a clean air introduction port 21 a is provided in the upper portion, and a gas exhaust and drainage port 21 b is provided in the lower portion. A clean air supply unit 22 is connected to the clean air inlet 21a. A pure water blowing nozzle 23 for supplying moisture to the resist is disposed inside the processing chamber 21. A pure water supply source 24 is connected to the pure water blowing nozzle 23. Although it does not specifically limit as water which supplies a water | moisture content, It is preferable to use a pure water.

  The pure water blowing nozzle 23 is disposed above the transport unit 30 and is preferably located at a position about 5 to 10 cm away from the substrate to be processed. The pure water blowing nozzle 23 passes through the plasma processing chamber 11 and sprays pure water onto the surface (resist formation surface) of the substrate 1 transported into the processing chamber 21 to supply moisture to the resist. The amount of pure water to be blown out and the temperature are appropriately adjusted, and if a large amount is blown out at a high pressure, the resist in a state where the adhesion is lowered can be surely blown off and removed. In addition, even when blown out with a weak pressure, the resist in a substantially peeled state is hydrolyzed and can be easily removed in a later process, and for example, it is reliably removed from the substrate in a separate peeling process or cleaning process (not shown). Is done.

  A drying device 25 is installed on the outlet side in the transport direction of the pure water blowing nozzle 23. The drying device 25 sprays pure water and supplies water to remove the resist 4, and blows air from the drying air blowing port to dry the substrate 1 on the substrate 1 wet with pure water. Is. The substrate 1 is unloaded from the processing chamber 21 after drying.

  The transport unit 30 is configured by a transport conveyor such as a belt conveyor or a roller conveyor. In this embodiment, a plurality of rollers 31 are arranged, and the resist is removed by rotating these rollers. The substrate 1 on which 4 is laminated is sequentially transferred from the plasma processing chamber 11 of the plasma processing unit 10 to the processing chamber 21 of the removal processing unit 20. The plasma processing chamber 11 and the processing chamber 21 are arranged adjacent to each other, and the substrate 1 exiting the plasma processing chamber 11 is configured to enter the processing chamber 21 quickly and continuously.

  The transfer unit 30 is not limited to the roller conveyor mechanism as described above. For example, the transfer unit 30 is moved by a mechanical linear motion mechanism, an air cylinder, a hydraulic cylinder, etc. May be transferred to the processing chamber 21, and is preferably capable of uniformly performing the resist removal process by transferring the substrate 1 at a constant transfer speed. The transport unit shown in FIG. 1 shows a type having a large number of rollers, and the transport unit shown in FIG. 2 shows a type in which a transport base that fixes the substrate 1 is moved.

In the resist removing apparatus D configured as described above, the inside of the plasma processing chamber 11 is brought into a predetermined gas atmosphere (for example, an air temperature of 20 ° C. and a humidity of 50% air) under a pressure near atmospheric pressure, and plasma Fluorine-based gas (CF ₄ : 100%) is supplied from the gas supply unit 17 to the plasma space 16 between the voltage application electrode 14a and the ground electrode 14b of the generation unit 13 to obtain a state under a pressure near atmospheric pressure, An electric field (for example, a pulse electric field) from the power supply 15 is applied between the voltage application electrode 14a and the ground electrode 14b. By applying this electric field, glow discharge plasma is generated in the plasma space 16 between the voltage application electrode 14a and the ground electrode 14b, and the CF ₄ gas (plasma gas) converted into plasma flows through the gas outlet 16b in the plasma space 16. Blow out.

Then, the CF ₄ plasmatized gas blown out from the gas blowout port 16b is used as a processing gas in the gas atmosphere (temperature 20 ° C., humidity 50% air) in the plasma processing chamber 11 as a resist 4.
Is irradiated onto the laminated substrate 1, the adhesion between the resist 4 and the substrate 1 is lowered. That is, when the resist laminated on the underlying aluminum film is irradiated with a plasma-based fluorine-based gas, most of the F ions are concentrated at the interface between the resist 4 and the underlying aluminum film 3. Then, there is almost no F ion in the resist.

  FIG. 4 shows the distribution of F ions before and after the resist plasma treatment. In FIG. 4, the vertical axis represents the number of atoms, and the horizontal axis represents the depth of the resist. That is, “0.0” on the horizontal axis represents the resist surface, the resist thickness is about 2.0 μm, and the depth of “2.0” is the underlying aluminum film. As is apparent from FIG. 4, after the treatment, most of the F ions are present at the interface between the resist 4 and the underlying aluminum film 3 and aggregate to process the interface. As a result, peeling occurs at the interface between the resist 4 and the surface of the underlying aluminum film 3, a gap is formed, and the adhesion is lowered.

For this reason, the F radicals generated by the atmospheric pressure plasma permeate the resist and form an aggregated layer at the interface between the resist and the base film. Thus aggregate layer at the interface between the resist and the underlying film is formed, and F radicals react with O _2, H 2 _O in the atmosphere COF ₂ is generated, after the COF ₂ is reacted with H _{2 O} Hydrofluoric acid (HF) is produced. This hydrofluoric acid dissolves the base film between the base film and the resist, and lowers the adhesion between the resist and the base film, thereby creating a gap at the interface and reducing the adhesion between the resist and the base film. Conceivable. Specifically, it is considered that [—COF ₂ ] is hydrolyzed (—COF ₂ + H ₂ O → COOH + HF) to dissolve the base film. Actually, when the cross-sectional portion of the interface between the resist and the base film after the plasma treatment was observed with a microscope, it was confirmed that the resist was lifted from the base film and was almost peeled off.

  The substrate 1 is subjected to a plasma process and a removal process for supplying moisture while being transported by the transport unit 30 at a predetermined scan speed (for example, 500 mm / min to 1000 mm / min). The scan speed can be set according to the type and thickness of the resist layered, and in the case of a resist with strong adhesion, the scan speed is slowed down to increase the plasma processing time and the removal processing time. Removal can be ensured. Further, the pressure in the plasma processing chamber 11 is not particularly limited, and it is sufficient that there is a differential pressure necessary for the processing gas to flow from the plasma generation unit 13 to the substrate 1.

The substrate 1 that has been subjected to the plasma processing in the plasma processing chamber 11 and thus the adhesion of the resist 4 has been lowered is transported by the transport unit 30 into the processing chamber 21 of the removal processing section 20, and from the pure water blowing nozzle 23. Moisture is supplied to the resist 4 with the blown pure water, and the resist is swollen and removed. That is, the resist 4 whose adhesion is lowered due to the spraying of pure water swells, is washed from the surface of the substrate 1 and falls off. For this reason, even a resist having strong adhesion to the base film can be reliably removed. Thereafter, it is dried by the drying device 25 and carried out of the processing chamber 21. In the above embodiment, CF ₄ is used as the fluorine-based gas for plasmatization, but the same effect can be obtained by using C ₂ F ₆ , CHF ₃ , and C ₃ F ₈ instead. Can do.

  In addition, the resist whose adhesion has been reduced by the plasma treatment is removed from the substrate surface by supplying and cleaning water by irradiating pure water. Instead, the resist substrate after the plasma treatment is treated with pure water. You may make it remove by swelling and peeling of a resist by immersing in the stored processing tank (not shown). In this case, the substrate having the resist whose adhesion is lowered by the plasma treatment is transported into the processing chamber 21 for supplying moisture, transported by the transport unit 30 and immersed in the processing tank in which pure water is stored, Moisture is supplied to the resist to swell and peel off.

  Furthermore, the resist whose adhesion has been lowered by the plasma treatment is first immersed in a treatment tank in which pure water is stored, and water is supplied to the resist to swell and float from the base film, and then the pure water blowing nozzle Alternatively, pure water may be blown from 23 to remove the resist with reduced adhesion by blowing off with water pressure. Thus, after performing the immersion process soaked in pure water first, by performing the spray process which sprays a pure water, the processing time of a resist removal process can be shortened significantly.

  Another embodiment of the present invention will be described in detail with reference to FIGS. FIG. 5 is a diagram schematically showing the configuration of another embodiment of the resist removing apparatus according to the present invention, and FIG. 6 is a cross-sectional view showing the configuration of the diffusion plate. Note that this embodiment is different from the above-described embodiment in that the plasma processing unit includes a line-shaped air outlet that blows out the plasma-based fluorine-based gas, and the plasma processing unit includes a diffusion member that widens the irradiation width of the air outlet. It is characterized by that. Other substantially equivalent configurations are denoted by the same reference numerals, and detailed description thereof is omitted.

  This embodiment is suitable when the substrate as the material to be processed is large. When removing a resist on a large glass substrate used in a liquid crystal display or the like by low-pressure plasma treatment, it is necessary to treat the resist with an electrode having a size equal to or larger than that of the substrate. Further, when such a large substrate is carried out by the atmospheric pressure plasma processing, a very large amount of electric power and processing gas are required, which is not practical. In actuality, while moving the material to be processed, the atmospheric pressure plasma is discharged in a line shape, and the processing gas activated by passing through the discharge portion is sprayed onto the substrate. For this reason, a processing part becomes a line shape, and when processing the whole board | substrate, since a board | substrate is moved and processed, very much time is required.

  In the present embodiment, in order to solve the above-mentioned problems, the processing width is widened by installing a diffusion plate 35 that widens the irradiation width of the plasmified gas below the line-shaped plasma generation section, and the power used for the processing. And processing gas can be suppressed. The plasma generating part is provided with a flat counter electrode 14 as in the above-described embodiment, and the gas outlets of the plasma space 16 between the counter electrodes are line-shaped. The diffusion plate 35 is installed below the line-shaped gas outlet, and is formed with an upper plate member 36 having two introduction slits 36a facing the plasma generator 13 and a plurality of discharge slits 37a in parallel. The lower plate member 37 is laminated with a space therebetween, and a middle space portion serves as a gas flow passage 38. The two introduction slits 36a of the diffusion plate 35 are opened upward, and the plurality of discharge slits 37a are opened downward.

  When the diffusion plate 35 configured as described above is attached, the processing gas (plasmaized gas) blown out from the gas blowing port 16b enters the gas flow passage 38 of the diffusion plate 35 through the introduction slit 36a, and a plurality of parallels. From the discharge slit 37a toward the substrate 1. In this way, the processing gas is blown out from a plurality of slits, and the processing width can be widened by increasing the irradiation width of the outlet, and the resist removal process is reliably executed even when the transport speed of the substrate 1 is increased. It can be shortened.

Examples of the present invention will be described below.
<Example 1>
[substrate]
Base: glass substrate, SiO ₂ film, a-Si film, SiNx film, aluminum film, Cr film, Mo film Resist resin: Novolak resin was applied on the entire surface and then baked. The thickness is 1.2 μm.
[Plasma conditions]
Fluorine gas: CF ₄ (100%)
Plasma treatment atmosphere: Air temperature 20 ° C, humidity 50% air [Power supply conditions]
Applied voltage: 10 kV
Frequency: 25 kHz (pulse electric field)
[Conveying speed]
500mm / min

A glass substrate, a SiO ₂ film, an a-Si film, a SiNx film, an aluminum film, a Cr film, and a Mo film are used as a base for forming a resist layer, and the resist of the present invention is applied to the resist applied to each base. A removal method was carried out. The result of removing the resist was confirmed by microscopic observation. As a result, the resist could be reliably removed on the base other than the Cr film and the Mo film. As described above, the resists laminated on the various kinds of substrates can be easily peeled and removed without being limited to the underlying film.

  From the results of Example 1, the base sample from which the resist was removed is a film in which the base can be dissolved in hydrofluoric acid (HF). After the plasma treatment, F ions of the fluorine-based gas aggregate at the interface between the resist and the base film, and the adhesion of the base film is lowered by dissolving the surface of the base film by hydrolysis at the interface. Then, the resist can be removed by a wet process of supplying water in a later process. Therefore, it is preferable to perform a wet process for supplying moisture immediately after the plasma process.

<Example 2>
As shown in FIG. 5, the substrate 1 on which the resist 4 was laminated was subjected to plasma treatment by attaching a diffusion plate 35 to the line-shaped plasma generator 13, and then the resist was removed by washing with water. The removed state of the resist was confirmed by microscopic observation. The removal process could not be performed with a line plasma apparatus alone unless the conveying speed was 0.05 m / min or less. However, when the diffusion plate 35 was attached, the removing process could be performed even with a conveying speed of 0.2 m / min or less. By attaching the diffusion plate in this way, the processing speed of the resist removal process could be improved.

<Example 3>
As shown in FIG. 7, in the line-shaped plasma generation unit 13 to which the diffusion plate 35 is attached, the substrate 1 on which the resist is laminated is processed in a fixed state, and the case where the substrate is moved by the transport unit and scanned. Compared. The length of the diffusing plate 35 in the scanning direction was set to 400 mm, and the size of the substrate 1 was set to a dimension that was sufficiently covered by the plasmaizing gas blowing range of the diffusing plate 35. The spray irradiation time is a time for spraying pure water onto the surface of the substrate 1 in a wet process for supplying moisture after the plasma process.

  Table 1 shows a comparison result of the resist removal process. As is clear from Table 1, in both cases of the fixing process and the scanning process, the resist could be reliably removed by setting the plasma processing time to 120 seconds or longer. Thus, it can be seen that if the plasma treatment is performed with a constant plasma irradiation time, the resist can be removed reliably in both the fixing treatment and the scanning treatment, and the treatment method is not limited.

<Example 4>
As a wet process for supplying moisture to the resist whose adhesion was reduced by the plasma process, a comparison was made between a process in which the substrate 1 is immersed in a pure water tank and a spray process in which pure water is sprayed after the immersion process. In order to complete the resist removal process in a short time, it is effective to perform the immersion process and the spray process continuously. In this case, pure water permeates the interface between the resist and the base film by the dipping treatment, and the resist is swollen and peeled off. Then, the resist that has been swollen and peeled off is removed by being blown away by pure water having a striking force such as spraying.

  Therefore, the processing time of the resist removal process can be shortened by continuously performing the two processes of the immersion process and the spray process. It took 70 seconds when the resist removal process was performed only by the spray process under the same conditions, but when the spray process was performed following the immersion process, the resist could be removed in 45 seconds. Under any condition, no change such as cloudiness was observed on the surface of the glass substrate after the resist 4 was removed, and no damage to the glass substrate was observed.

  Although one embodiment of the present invention has been described in detail above, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention described in the claims. Design changes can be made. For example, an example of a treatment tank for immersing the substrate in pure water or a nozzle for spraying pure water on the resist is shown as a removal processing unit that performs wet processing to supply moisture to the resist, but an ultrasonic humidifier or the like is used. It goes without saying that moisture may be supplied to the resist, or moisture may be supplied by spraying steam. In the case of steam, the resist can be swollen quickly, and hydrolysis is also carried out quickly, which is preferable. The resist may be either directly laminated on the base substrate or laminated on a thin film formed on the base substrate, and the present invention can be applied to removing either resist.

  As an application example of the present invention, the resist removal apparatus of the present invention is a plasma apparatus having a remote plasma processing unit, and can be connected in-line to an existing processing line for spraying pure water.

The figure which shows typically the structure of one Embodiment of the resist removal apparatus of this invention. The figure which shows typically the structure of the plasma processing part of FIG. The principal part sectional view showing typically the substrate which processes in the embodiment of the present invention. Explanatory drawing which shows the distribution condition of F ion before and after plasma processing. The figure which shows typically the structure of the plasma processing part of other embodiment of a resist removal apparatus. Sectional drawing which shows the structure of the diffusion plate of FIG. Explanatory drawing of Example 3 which compares the fixing process of a resist removal using a diffusion plate, and a scanning process.

Explanation of symbols

  1: substrate, 2: epoxy substrate (base substrate), 3: aluminum film (base), 4: resist, 10: plasma processing unit, 11: plasma processing chamber, 12: atmosphere gas supply unit, 13: plasma generating unit, 14: counter electrode, 14a: voltage application electrode, 14b: ground electrode, 15: power supply, 16: plasma space, 16a: gas inlet, 16b: gas outlet, 17: gas supply unit, 18: gas supply line, 20 : Removal processing unit, 21: processing chamber, 23: pure water blowing nozzle, 24: pure water supply source, 30: transport unit, 35: diffusion plate (diffusion member), 36a: introduction slit, 37a: discharge slit, 38: Distribution passage, D: Resist removal device

Claims (5)

A method of removing a resist laminated on a substrate,
A step of reducing the adhesion between the resist and the substrate by converting the fluorine-based gas into plasma and irradiating the resist under a pressure near atmospheric pressure, and a resist whose adhesion is lowered by supplying moisture to the resist And removing the substrate from the substrate.   The resist removal method according to claim 1, wherein the moisture is supplied to the resist by a process of spraying pure water on the substrate and / or a process of immersing the substrate in pure water. An apparatus for removing a resist formed on a substrate,
A plasma processing unit that lowers the adhesion between the resist and the substrate by converting the fluorine-based gas into plasma and irradiating the resist under a pressure near atmospheric pressure;
A resist removal apparatus, comprising: a removal processing unit that supplies moisture to the resist whose adhesion has been lowered and peels the resist from the substrate to remove the resist.   4. The resist removal apparatus according to claim 3, wherein the plasma processing unit includes a line-shaped blowout port for blowing out the plasma-ized fluorine-based gas, and a diffusion member that widens the irradiation width of the blowout port. . 5. The resist removal apparatus according to claim 3, wherein the removal processing unit includes a nozzle for spraying pure water onto the resist on the substrate and / or a treatment tank for immersing the substrate in pure water.

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