JP2008119560A - Steam focusing nozzle and cleaning process - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steam nozzle removing an object to be washed by centralizing steam on a treatment substrate after a steam eruption and utilizing the centralization of a thermal energy and hitting power. <P>SOLUTION: The steam is dispersed on a dispersion board inside the nozzle and the dispersed steam is sprayed to a focusing point on the nozzle central axis at a tapered side wall by Coanda effect. The use of the focusing nozzle having this construction prevents a reduction in the temperature of a high-temperature fluid observed in a general circular nozzle to enable a spraying of the steam good in temperature efficiency on the treatment substrate. Further, the effective use of the thermal energy and the hitting power of the steam centralized by the focusing nozzle enables the cleaning of particles which have been difficult to remove, and the removal of a resist film or the like. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to cleaning and resist removal of a semiconductor substrate, a glass substrate for liquid crystal, a glass substrate for PDP, and a plastic substrate.

As a conventional resist removal method, a method using a chemical solution has been mainly used, but recently, a resist removal method using vapor without using a chemical solution has been proposed.

According to Patent Document 1, a wafer is placed in a container in a resist removal apparatus, vapor is injected and filled into the container from a nozzle, and the pressure in the container is increased to liquefy the vapor and penetrate the wafer. Thereafter, there is a method of removing the resist by generating a crack in the resist by reducing the pressure in the sealed state and vaporizing a part again. However, this method requires a highly airtight container, pressurizing device, and decompressing device, and thus there is a problem that the cost of the device increases as the semiconductor, liquid crystal substrate, and PDP substrate increase in size.
JP 2005-259743 A

The resist remover injection device proposed in Patent Document 2 includes a heating plate as a removing agent vaporizing means inside a vertically long cylindrical hollow container, and an organic base and an organic solvent are provided up to the surface of the heating plate. It is comprised so that the removal agent containing can be introduce | transduced. The removing agent is vaporized and sprayed toward the resist film forming surface of the substrate to remove the resist film. In the embodiment of the present invention, a resist film removal experiment is performed by spraying steam with a fan-shaped nozzle (divergence angle of about 80 degrees). First, when the resist was removed only with vapor, the distance between the nozzle tip and the substrate was changed, but it was confirmed that the resist film could not be removed if the distance was long, and could only be removed if the distance was shortened. However, this process takes time. In order to improve this, the removal time of the resist film is shortened by introducing a remover (peeling solution) into the nozzle, evaporating it with a heating plate and injecting the remover together with the vapor onto the substrate. However, this method requires a heating plate in the temperature-controlled chamber or nozzle, which complicates the structure. Also, as the semiconductor, liquid crystal substrate, and PDP substrate become larger, the device cost increases and the amount of chemicals used increases. Such a problem is considered.
JP 2005-259862 A

As a result of removing the resist film only with water vapor, the example of Patent Document 2 reveals that the distance between the nozzle tip and the substrate is related to the resist removal. The nozzle used in this experiment is a wide-angle flat-type steam injection nozzle, which injects steam at a wide angle. This nozzle is suitable for injecting a normal temperature gas or liquid, but has a demerit that when high temperature fluid such as saturated steam or superheated steam is injected, ambient air is involved and the temperature is lowered.

Other nozzles include a divergent nozzle and a slit nozzle. The divergent nozzle is a steam nozzle that is designed to be throat-shaped from the nozzle entrance and become atmospheric pressure by adiabatic expansion. This nozzle is suitable for increasing the jetting force, but is designed so that the jet spreads at a certain angle, so that the surrounding fluid is involved and the steam temperature is lowered. The slit nozzle is a nozzle that has a linear slit in the width direction and obtains a uniform jet in the width direction, and is used as a nozzle for pure water cleaning or substrate drying. When the jet flowing from this nozzle is viewed from the direction orthogonal to the width direction, the jet spreads while entraining the surrounding fluid. Even in the case of this nozzle, the steam temperature decreases.

Therefore, it is expected to develop a steam nozzle that prevents the steam temperature from decreasing, concentrates the steam on the processing substrate, and removes the object to be cleaned by using the concentration of thermal energy and striking force.

As described above, since the conventional nozzle has a divergence angle while entraining the surrounding fluid after the steam is ejected, the problem is that the steam temperature is lowered after the steam is injected and the temperature efficient steam is not injected onto the processing substrate. There is.

Therefore, a steam nozzle is provided that prevents a drop in the steam temperature found in conventional nozzles, concentrates the steam on the processing substrate, and removes the object to be cleaned using the concentration of thermal energy and striking force.

According to Non-Patent Document 1, when a jet flow is ejected from a general circular nozzle (three-dimensional axis target nozzle) into an infinitely wide space, a large velocity gradient (velocity difference) between the surrounding fluid and viscous action As a result, it flows in the downstream direction while entraining the surrounding fluid and widening the jet width. Since the circular nozzle has such characteristics, when steam is jetted, the surrounding fluid is entrained between the jetting outlet and the processing substrate surface, and the temperature is lowered. In the nozzle of the present invention, the vapor is once dispersed inside the nozzle, takes a flow path that guides to the converging point downstream of the jet outlet along the tapered surface by the Coanda effect, and there is no divergence angle in the conventional nozzle. It is possible to prevent a decrease in vapor temperature between the surfaces of the processing substrates.
Toshihiko Kawauchi, “Journal Engineering” p3, published by Morikita Publishing Co., Ltd., March 2004.

Hereinafter, the difference between a general circular nozzle and the focusing nozzle of the present invention will be described with reference to specific drawings. FIG. 1 shows a vapor jet explanatory diagram of a general circular nozzle, and FIG. 2 shows a vapor jet explanatory diagram of a focusing nozzle. In the circular nozzle of FIG. 1, the vapor having a flow rate Q passes through a circular hole (pipe) having a diameter d without changing its speed, and is jetted from the jet port 42, and reaches the processing substrate surface 6 at a distance h from the jet port 42. The jet coming out of the jet outlet entrains the surrounding fluid (arrow a) and reaches the surface of the processing substrate while widening the divergence angle. At this time, the spray area of the steam sprayed onto the surface of the processing substrate is A. On the other hand, in the focusing nozzle shown in FIG. 2, the vapor having a flow rate Q passes through a circular hole having a diameter d, and after colliding with the dispersion plate 31, the dispersion plate inclined surface and the hemispherical side wall 31 and the tapered side wall 41 are It converges on the processing substrate surface at a distance h from the jet nozzle 42 via the side wall. The steam injection area at this time is B. In the case of a general circular nozzle, since it has a divergence angle, the jetting area A is larger than the circular hole diameter d. Therefore, when saturated steam having the same flow rate is introduced into the same hole diameter d, it is possible to concentrate the striking force in a focusing nozzle having a small injection area.

In order to confirm the concentration of steam in the focusing nozzle of the present invention, the steam temperature distribution in the vicinity of the jet outlet was measured. FIG. 3 shows the temperature distribution measurement result in the vicinity of the jet nozzle in the focusing nozzle. The diameter of the steam introduction part circular hole was d = 2 mm, and saturated steam at 102 ° C. was introduced. The center of the jet outlet 42 is the coordinate origin (r = 0, h = 0), and the chromel-alumel thermoelectric is in the range of downstream direction h = 0-8mm and radial direction r = 0-3mm and r = 0-3mm. Steam temperature was measured using a pair. The gray part (a) is a region where the steam temperature is 100 to 102 ° C., and is a region from the position of the tapered side surface (b) and c of the injection port to the point (e) via the converging point (2). This coincides with the white lines of the steam flow in the design of the nozzle of the present invention (b), c, and c, and the steam passes through this flow path and joins at the focal point 2 to reach the steam. It can be seen that the temperature is maintained. From the above, in the focusing nozzle, it has been possible to concentrate the steam and prevent the steam temperature from being lowered.

Next, in order to confirm the steam temperature drop in the circular nozzle as a comparison, the steam temperature distribution in the vicinity of the jet nozzle was measured. FIG. 4 shows the result of measuring the temperature distribution in the vicinity of the jet nozzle in the circular nozzle. The diameter of the nozzle introduction part circular hole was d = 2 mm, and saturated steam at 102 ° C. was introduced. The center of the jet outlet 42 is the coordinate origin (r = 0, h = 0), and the chromel-alumel thermoelectric is in the range of downstream direction h = 0-8mm and radial direction r = 0-3mm and r = 0-3mm. Steam temperature was measured using a pair. The steam temperature was 102 ° C. at the injection port and 90 ° C. at a point 5 mm away from the injection port. Therefore, in the case of a circular nozzle, it has been confirmed that the steam temperature decreases as the distance from the injection port increases.

Therefore, by using the focusing nozzle of the present invention, it is possible to prevent a drop in steam temperature seen in a general circular nozzle, to concentrate the steam, and to concentrate the heat energy and the striking force.

As described above, by using the nozzle of the present invention, it is possible to concentrate the vapor on the processing substrate, and to perform cleaning and target removal using the concentration of thermal energy and striking force.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIGS. 5 to 7 relate to the first embodiment of the present invention, FIG. 5 is a sectional view of the focusing nozzle structure showing the best embodiment of the nozzle of the present invention, FIG. 6 is a jet model diagram, and FIG. it is a model diagram showing a F _y.

As shown in FIG. 5, the nozzle 1 of the present invention is a three-dimensional axis target nozzle configured from three parts, a steam introduction part 2, a dispersion part 3, and a focusing part 4. The steam introduction part 2 is provided with a steam flow path composed of a cylindrical tube having a diameter d and a length L. The dispersion part 3 has a conical dispersion plate 32 arranged on the central axis in a hemispherical cavity having a radius r, and a steam channel is provided in a gap between the slope of the dispersion plate 32 and the inner wall 31 of the hemispherical cavity. ing. The converging unit 4 includes a flow path that narrows in a tapered shape.

In order to explain the function of the nozzle of the present invention, a steam flow path when steam is introduced will be described. The steam 5 is introduced from the introduction port 21 of the introduction part 2, passes through the circular hole 22, collides with the apex “a” of the conical dispersion plate 32 of the dispersion part 3, and is dispersed into the axial target form. The dispersed steam flows along the inclined surface of the conical dispersion plate by the Coanda effect, and collides with b of the hemispherical cavity inner wall 31. Again, the Coanda effect is guided along the hemispherical cavity inner side wall 31 and the tapered side wall 41 to the jet outlet 42 and injected from the outlet. The jet steam is focused on a point 61 at a distance h from the jet port on the nozzle central axis.

Dispersing the vapor impinges at an angle of T ₃₂ hemispherical cavities in the side wall 31 at point b, but described diversion of the jet that time. FIG. 6 shows a jet model when the jet strikes the wall at an angle. According to Non-Patent Document 2, when the jet collides with the wall at an angle forming T with the wall, the relationship between the jet Q before the collision and the jets Q _a and Q _b after the collision is expressed by Equations 1 and 2. Increasing the jet Q _a in the traveling direction of the steam from the equation reduces the jet Q _b in the opposite direction, in order to obtain a smooth vapor flow to the traveling direction, minimizing the incidence angle T ₃₂ in the present invention the nozzle I know that I should do.

Maeda Masanobu, “The first fluid dynamics” p84, published by Ohmsha Publishing Co., Ltd., October 2002.

Distributed steam guided to the ejection port along the tapered side wall by the Coanda effect at the focusing unit impinges at an angle of substrate and T ₄₁ becomes straight jet. FIG. 7 is a model diagram showing the striking force Fy to the processing substrate. Figure in the case of jet Q _a impinges at an angle of substrate and T _41, it shows a batting power, batting power Fy to substrate vertically downward direction is represented by Fy = FsinT _41. Therefore, by increasing the taper angle T ₄₁ of the tapered side walls, it is possible to increase the liquid-driving power to the substrate vertically downward direction.

Further, Non-Patent Document 3, in the inclined 2 jet impingement to impinge at an angle to the jet, the larger the collision angle T _41, it is shown that the jet width decreases.
Koichi Enomoto, Toshihiko Kochiuchi, Toshihiro Ando, “Numerical Simulation on Mixing Control of Jet”, Osaka University Cyber Media Center Large-scale Computer System User Report vol.1, No.1, 2005.5 No.1.

From the above, the size of the focusing nozzle was set as follows. The diameter d of the circular hole 22 is 2 mm, the length L of the circular hole 22 is 10 mm, the radius r of the hemispherical cavity 31 is 10 mm, the dispersion angle T ₃₁ of the conical dispersion plate 32 is 60 degrees, and the collision angle T at the point b. ₃₂ = 45 degrees, the diameter f of the bottom surface of the dispersion plate f = 6.8 mm, the taper angle T ₄₁ of the tapered side wall ₄₁ = 60 degrees, the distance e = 2 mm between the injection hole of the circular hole 22 and the apex a of the conical dispersion plate did.

(Example 1)
(Resist removal experiment)

The results of a resist removal experiment using the nozzle of the present invention will be described below.
Saturated steam (steam flow rate 100 L / min) generated by a steam boiler is introduced into the steam inlet 21 of the nozzle 1, and a substrate with a resist film is placed at the converging point 61 so as to be orthogonal to the central axis of the nozzle. Steam was sprayed toward. The resist used at this time is a positive-type photoresist for g-line wavelength, which is previously applied with a spin coater and baked at 100 ° C. for 10 minutes on a hot plate. FIG. 8 is a photograph showing the resist removal process. It shows that a crack occurred on the resist film surface 10 seconds after the start of vapor jetting, and the resist film could be removed locally after 20 seconds. An experiment similar to that of the focusing nozzle was performed using a circular nozzle, but no change was observed on the resist surface.

Thus, it was proved that by using the focusing nozzle of the present invention, the vapor can be concentrated on the processing substrate, and the resist film can be removed by utilizing the concentration of thermal energy and striking force.
(Example 2)

In the focusing nozzle according to the first embodiment of the present invention, a liquid nozzle is newly installed at the center of the shaft, and a chemical solution such as a surfactant, an etching solvent, a resist stripping solution, pure water, or alkaline electrolyzed water is supplied from the liquid nozzle together with the vapor. By flowing functional water such as hydrogen or hydrogen water at a constant ratio, more effective cleaning, etching, or resist stripping using the temperature effect of steam can be performed. By using this two-fluid nozzle, a temperature control facility for the chemical solution is not required, and a reduction in the amount of chemical solution used and a reduction in device cost are expected.

As mentioned above, although embodiment and the Example of this invention were described, the scope of the present invention is not limited to this. In the nozzle according to the first embodiment of the present invention, the dispersion plate of the dispersion portion has a conical shape, but may have a semicircular shape, a pyramid shape, a quadratic curved surface, or a shape having an inclined surface of a cubic curved surface. Any mechanism may be used as long as it causes steam to collide with the apex or the center and guide the steam along the inclined surface by the Coanda effect.

Further, in the nozzle of the first embodiment of the present invention, the dispersion part is a hemispherical cavity and the dispersed vapor collides with the curved side wall, but even if it is a cylindrical cavity having a tapered side wall and changing in diameter at a certain rate. The cavity may have a taper angle that is developed in multiple stages so that dispersed steam can easily enter.

Further, in the nozzle of the first embodiment of the present invention, the converging part has a tapered side wall with a cylindrical cavity whose diameter changes at a constant rate, and the steam is guided to the converging point along the tapered side wall by the Coanda effect. It may not be a straight side wall with a constant taper angle, but may be a combination of straight side walls with a taper angle of two or more steps or a curved side wall.
(Example 3)

FIG. 9 is a sectional view showing the configuration of a focusing nozzle with a heat insulating skirt. The heat insulation skirt 51 is added to the lower portion of the injection port, and has a hollow disk shape with an inner diameter R51, an outer shape R52, and a thickness of several millimeters. By adding the heat insulating skirt, it is possible to prevent the surrounding fluid from being caught and to allow the vapor flow after focusing to flow radially along the surface of the processing substrate. Using this vapor flow, not only the surface of the processing substrate is overheated, but also contaminants and exfoliation such as resist can be carried on the air current and carried outside the processing target region. Furthermore, by increasing the outer diameter R52 of the heat insulating skirt, a large area on the surface of the processing substrate can be heated, so that there is an effect of shortening processing time such as cleaning and resist stripping. The shape of the heat insulation skirt is not limited to this. However, it is necessary to have a shape that does not obstruct the flow path of the dispersed vapor flowing along the tapered side wall due to the Coanda effect. In FIG. 9, the inner diameter R51 of the hollow disc is made larger than the injection port diameter R41 so as not to obstruct the flow path.

Moreover, although the nozzle of the first embodiment of the present invention is a three-dimensional axis target nozzle, it may be a two-dimensional wide nozzle applied to a linear conveying apparatus. The cross-sectional shape of the dispersion plate may be triangular or semicircular and long in the lateral width direction.

Further, the nozzle of the present invention is implemented in a cleaning apparatus, an etching apparatus, or a resist removal apparatus used for a cleaning process, an etching process, or a resist removal process of a semiconductor, a liquid crystal glass substrate, a PDP glass substrate, and an LCD mounting substrate. It is used by being mounted on a spin rotation device or a linear conveyance device. In that case, the nozzle may be a larger nozzle according to the size of the substrate, or the same nozzle may be arranged in a plurality of stages.

Further, the nozzle of the present invention can be used as a general cleaning nozzle for tableware cleaning, automobile cleaning, and the like, which remains within the technical scope of the above field. This nozzle can be used not only for steam cleaning but also as a cleaning nozzle using a high-temperature fluid.

INDUSTRIAL APPLICABILITY The present invention can be used in a cleaning process and a resist removal process in the manufacturing field of conductors, glass substrates for liquid crystals, FPD glass substrates, quartz substrates for masks, silicon wafers, various media substrates, and the like.

It is steam jet explanatory drawing of a general circular nozzle. It is vapor jet explanatory drawing of the focusing nozzle of this invention. It is a graph which shows vapor | steam temperature distribution of a jet nozzle vicinity in the focusing nozzle of this invention. It is a graph which shows the vapor | steam temperature distribution of a jet nozzle vicinity by a circular nozzle. It is a structure sectional view showing the best embodiment of the focusing nozzle of the present invention. It is a jet model figure when a jet hits a flow with respect to a wall diagonally. It is a model figure which shows the impact force Fy to the process board | substrate of a steam jet in a converging point. It is a photograph figure which shows a resist removal experiment result. It is a structure sectional view of a focusing nozzle with a heat insulation skirt.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Nozzle 2 Steam introducing part 3 Dispersing part 4 Converging part 5 Steam 6 Process substrate 21 Inlet 22 Circular hole 31 Semi-spherical inner wall 32 Conical dispersion plate 41 Tapered side wall 42 Spout 51 Heat insulating skirt 61 Focusing point

Claims (9)

A steam nozzle having a structure in which steam is dispersed and guided to a converging point on the central axis of the nozzle by a tapered side wall. The steam nozzle according to claim 1, comprising a steam introduction part, a dispersion part, and a converging part, and comprising a circular hole, a dispersion plate, and a tapered side wall. 3. The steam nozzle according to claim 1, wherein the dispersion plate has a conical shape, a polygonal pyramid shape, a spherical shape, or a shape having an inclined surface of a quadric surface or a cubic surface. The tapered side wall is a straight side wall having a constant taper angle, a combination of straight side walls having a taper angle of two or more, a curved side wall, or a combination of a straight side wall and a curved side wall. Item 3. A steam nozzle according to items 1 to 3. The steam nozzle according to claim 1, wherein a hollow disk-like heat insulation skirt is installed in the lower part of the steam nozzle to prevent the surrounding fluid from being caught and to improve heat insulation. 6. A steam nozzle according to claim 1, wherein a liquid nozzle is provided near the center in the converging part, and the liquid introduced from the liquid nozzle has a function of mixing near the converging part. The steam nozzle according to claim 1, wherein the steam nozzle is a three-dimensional axis target nozzle or a two-dimensional wide nozzle. A cleaning method or a resist removal method, wherein particles, oils, organic substances, glass cullet, resist, and the like are removed using the vapor nozzle according to claim 1. The liquid introduced from the liquid nozzle according to claim 6 is a surfactant, an etching solvent, a chemical solution such as a resist stripping solution, pure water, functional water, or the like, and this liquid is mixed with steam at a constant ratio in the vicinity of the focusing portion. A cleaning method and a resist removal method characterized by removing particles, fats and oils, organic matter, glass cullet, resist, and the like using temperature effects.