TWI651752B - Etching device, etching method, method of manufacturing substrate, and substrate - Google Patents

Abstract

The etching apparatus (100) of the present invention includes an etching tank (110) having a substrate carrying inlet (111) and a substrate carrying outlet (112), and a conveying device (120) that is moved from the substrate carrying inlet (111) toward the substrate. (112) transporting the substrate (500); the nozzle (130) is disposed inside the etching bath (110), and blowing the reaction gas to the back surface (510) of the substrate 500 transported by the transport device (120); and the air flow control device (140), which is disposed inside the etching bath (110), and prevents external air flowing into the etching tank (110) from the substrate carrying inlet (111) and the substrate carrying outlet (112) from flowing into the back surface (510) of the substrate (500) and A gap (131) between the nozzles (130).

Description

Etching device, etching method, method of manufacturing substrate, and substrate

The present invention relates to an etching apparatus, an etching method, a method of manufacturing a substrate, and a substrate.

It is known that in the manufacturing process of a flat panel display, it is known that the substrate is charged by static electricity generated when the substrate is in contact with a stage or the like. Therefore, in order to suppress such charging, it has been proposed that the substrate is placed on the side of the platform or the like (hereinafter referred to as "back surface"), and the back surface of the substrate is roughened by etching with a plasma containing an HF-based gas. Method (for example, refer to Patent Document 1). Further, a method of reacting a fluorine-containing gas with steam and a plasma to generate a reaction gas containing an HF-based gas, and blowing the reaction gas onto a substrate to etch the substrate is known (for example, see Patent Document 2).

As the etching apparatus, a configuration in which a substrate carrying port and a substrate carrying port are provided in a groove for performing chemical treatment of a glass substrate (hereinafter referred to as "etching groove") is known (for example, see Patent Document 3). In order to continuously carry out the process of loading the substrate into the substrate, the substrate transfer port and the substrate transfer port are opened, and the substrate is transferred from the substrate transfer port to the substrate transfer port, and the reaction gas is supplied from the nozzle provided on the substrate transfer path. Blow to one side of the substrate.

[Previous Technical Literature] [Patent Literature]

Patent Document 1: International Publication No. 2010/128673

Patent Document 2: Japanese Patent Laid-Open No. 2007-201067

Patent Document 3: Japanese Patent Laid-Open Publication No. 2012-216581

The thickness of each portion in the back surface of the substrate is determined based on the concentration of the reaction gas exposed at the portion thereof and the cumulative time at which the portion is exposed to the reaction gas. These factors may vary greatly due to airflow disturbances caused by external air flowing in from the substrate transfer port and the substrate transfer port. However, in the prior etching apparatus, since the influence of the airflow disturbance cannot be sufficiently suppressed, the unevenness of the thickness occurs as the outside air flows into the inside of the etching bath. As a result, it is difficult to reduce the amount of charge of static electricity in the back surface of the substrate.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an etching apparatus and an etching method capable of suppressing thickness unevenness caused by external air flowing into an etching bath.

An etching apparatus according to an aspect of the present invention includes: an etching tank having a substrate carrying port and a substrate carrying port; and a conveying device that transports the substrate from the substrate carrying port toward the substrate carrying port; and the nozzle is disposed inside the etching groove a reaction gas is blown to one surface of the substrate conveyed by the transfer device, and a gas flow control device is provided inside the etching groove to prevent the inside of the etching groove from flowing into the inside of the etching groove from the substrate transfer port and the substrate transfer port Air flows into a gap between one of the surfaces of the substrate and the nozzle.

In an etching apparatus according to an aspect of the present invention, the airflow control device may include: a first ventilation path that allows external air flowing into the etching groove from the substrate carrying inlet toward the gap, and is disposed at the substrate carrying inlet a first vent opening between the nozzle and the second venting path, the outside air flowing into the etching groove from the substrate carrying port toward the gap is provided between the substrate carrying port and the nozzle The second vent flows in.

An etching apparatus according to an aspect of the present invention may include: a connection path connecting the above a venting path and the second venting path described above.

An etching apparatus according to an aspect of the present invention may include: a suction device that sucks outside air flowing from the first ventilation path and the second ventilation path into the connection path.

In an etching apparatus according to an aspect of the present invention, the first ventilation path may be provided to block the front side of the nozzle as viewed from the substrate carrying inlet, and the front side of the nozzle may be blocked by observing the front side of the nozzle. The second ventilation path described above is set.

In the etching method of the present invention, the substrate is carried out from the substrate transfer port having the substrate transfer port and the substrate transfer port toward the substrate transfer port, and the etching port is prevented from flowing into the etching groove from the substrate transfer port and the substrate transfer port. The outside air flows into the gap between the one surface of the substrate and the nozzle, and the reaction gas is blown from the nozzle to one surface of the substrate.

In an etching method according to an aspect of the present invention, external air flowing into the etching chamber from the substrate carrying port toward the gap flows into the first vent port provided between the substrate carrying port and the nozzle. The air passage prevents the outside air flowing into the etching tank from the substrate carrying inlet from flowing into the gap, and the outside air that flows into the etching tank from the substrate carrying port toward the gap is provided in the substrate carrying port and The second vent port between the nozzles flows into the second air passage, and the outside air flowing into the etching tank from the substrate carrying port is prevented from flowing into the gap. In an etching method according to an aspect of the present invention, the inflow and the inflow connection may be The outside air of the connection path of the first ventilation path and the second ventilation path.

A method of manufacturing a substrate according to an aspect of the present invention includes a method of manufacturing a substrate in which a substrate is etched by the etching method.

A substrate according to an aspect of the present invention has a first surface and a substrate on a second surface opposite to the first surface, and an average value of an arithmetic mean surface roughness of the entire first surface is 0.3 to 1.5 nm. The average of the arithmetic mean surface roughness of the peripheral portion of the first surface and the center of the first surface The arithmetic mean surface roughness of the portion is different, and the standard deviation of the arithmetic mean surface roughness of the entire first surface is 0.06 or less.

In the substrate of one aspect of the invention, the substrate may have a size of 1500 mm × 1500 mm or more.

In the substrate according to one aspect of the invention, the difference between the arithmetic mean surface roughness of the central portion of the first surface and the average of the arithmetic mean surface roughness of the entire first surface may be -0.13 or more and 0.13 or less.

According to the present invention, it is possible to suppress the unevenness of the thickness caused by the flow of outside air into the inside of the etching bath.

100‧‧‧ etching device

110‧‧‧etching trough

111‧‧‧Substrate entrance

112‧‧‧Substrate removal

120‧‧‧Transporting device

121‧‧‧Roller

130‧‧‧Nozzles

131‧‧‧ gap

132‧‧‧ gas supply path

132a‧‧‧Blowing out

133‧‧‧First gas aspiration path

133a‧‧‧first suction port

134‧‧‧Second gas suction path

134a‧‧‧second suction port

135‧‧‧ top board

140‧‧‧Airflow control device

141‧‧‧First ventilation path

141a‧‧‧First back panel

141b‧‧‧ first front panel

141c‧‧‧First vent

142‧‧‧second ventilation path

142a‧‧‧second back panel

142b‧‧‧ second front panel

142c‧‧‧second vent

143‧‧‧first exhaust

144‧‧‧Second vent

144c‧‧‧First vent

150‧‧‧Connection path

160‧‧‧Suction device

500‧‧‧Substrate

510‧‧‧ back

520‧‧‧ positive

600‧‧‧ gas recovery unit

700‧‧‧ space

711‧‧‧Substrate entrance

712‧‧‧Substrate removal

730‧‧‧Nozzle

731‧‧‧ gap

732‧‧‧ gas supply path

732a‧‧‧Blowing

733‧‧‧First gas aspiration path

733a‧‧‧first suction port

734‧‧‧Second gas suction path

734a‧‧‧second suction port

741‧‧‧First ventilation path

742‧‧‧second ventilation path

750‧‧‧Substrate

751‧‧‧Back

1000‧‧‧Substrate Manufacturing System

1010‧‧‧First cleaning tank

1020‧‧‧First buffer tank

1030‧‧‧etching groove

1031‧‧‧Substrate entrance

1032‧‧‧Substrate removal

1040‧‧‧Second buffer tank

1050‧‧‧Second cleaning tank

1051‧‧‧High pressure shower

1070‧‧‧Transporting device

1071‧‧‧Roller

1080‧‧‧Nozzles

dA‧‧‧Size

dB‧‧‧Size

dC‧‧‧Size

dD‧‧‧Size

EXH1‧‧ vent

EXH2‧‧ vent

FFU1‧‧‧Fan filter unit

FFU2‧‧‧Fan filter unit

I1‧‧‧ distance

I2‧‧‧ distance

Fig. 1 is a side view schematically showing an etching apparatus according to a first embodiment of the present invention.

Fig. 2 is a cross-sectional view showing a nozzle of the etching apparatus according to the first embodiment of the present invention.

Fig. 3 is a front view of the nozzle and the air flow control device as viewed from the substrate carrying inlet side.

4 is a schematic view showing the flow of outside air in the etching bath, (a) showing a flow of external air when the first ventilation path and the second ventilation path are provided near the nozzle, and (b) showing not near the nozzle. A diagram showing the flow of outside air when such a ventilation path is set.

Fig. 5 is a side view showing a part of a substrate manufacturing system including an etching apparatus according to a first embodiment of the present invention.

6 is a view showing a distribution of air pressure fluctuation around the nozzle when the etching groove does not include the air flow control device, wherein (a) shows a state in which the end portion of the substrate reaches the vicinity of the nozzle, and (b) the substrate is transferred from the substrate transfer port to the substrate. (c) a diagram showing a state in which the end portion of the substrate is conveyed to the vicinity of the nozzle.

7 is a diagram showing a numerical simulation calculation model relating to a concentration distribution of a reaction gas, (a) showing a calculation model of a space lower than a substrate in an etching bath, and (b) expanding a gap between a nozzle and a substrate in the simulation space. Figure.

Fig. 8 is a graph showing the dependence of the suction pressure on the numerical simulation results relating to the concentration distribution of the reaction gas, and (a) shows an example of the result of calculating the concentration distribution of the reaction gas in the gap in the comparative example before the introduction of the gas flow control device. Fig., (b), (c) and (d) are graphs showing the calculation results of the examples for PBB = -0.5 Pa, -1 Pa, -1.5 Pa, in order.

Fig. 9 is a graph showing the dependence of the suction pressure on the numerical simulation results relating to the concentration distribution of the reaction gas, (a) showing the calculation results of the comparative examples, and (b), (c) and (d) are sequentially displayed. A graph of the calculation results of the examples at PBB = -0.5 Pa, -1 Pa, -1.5 Pa.

In the embodiment of the present invention, description will be made using Figs. 1 to 4 . FIG. 1 is a side view schematically showing an etching apparatus 100. 2 is a cross-sectional view of the nozzle 130. Fig. 3 is a front view of the nozzle and the air flow control device viewed from the substrate carrying inlet side. Figure 4 is a schematic diagram showing the flow of outside air in an etch bath. 4(a) is a view showing the flow of outside air when the first ventilation path 141 and the second ventilation path 142 are provided in the vicinity of the nozzle 130, and FIG. 4(b) shows that the ventilation path is not provided near the nozzle 130. A map of the flow of outside air. In Figs. 4(a) and 4(b), the flow of the outside air is indicated by a thicker arrow.

Hereinafter, the etching apparatus 100 of the present embodiment will be described with reference to Fig. 1 .

As shown in FIG. 1, the etching apparatus 100 includes an etching bath 110, a conveying device 120, a nozzle 130, and a gas flow control device 140. The etching apparatus 100 performs a chemical treatment using an external air piezoelectric slurry on one surface of the substrate 500 (for example, the back surface 510). Thereby, the surface of one of the substrates 500 is roughened.

The substrate 500 is, for example, a glass substrate used for a liquid crystal display, a flat panel display of an organic EL display, an organic EL illumination, a solar cell, a battery, or the like. The substrate 500 is cut into a rectangular shape in the manufacturing process of the substrate 500 to be described later. The size of the substrate 500 is, for example, 2880 mm in the width direction (the direction orthogonal to the plane of the drawing in FIG. 1), and 3130 mm in the conveyance direction (the horizontal direction in the paper surface in FIG. 1). Further, the thickness of the substrate 500 is, for example, 0.6 mm. In addition, the size and thickness of the substrate 500 are not limited to the equivalent. The shape of the substrate 500 is also not It is limited to a rectangular shape and may be a circular shape or a ribbon shape.

The etching bath 110 has a substrate carrying inlet 111 and a substrate carrying port 112. The substrate transfer port 111 and the substrate transfer port 112 are located at the same height as shown in FIG. 1 . The substrate carrying inlet 111 and the substrate carrying opening 112 have a slit shape extending in the width direction of the substrate 500. The width of the substrate carrying port 111 and the substrate carrying port 112 (the length in the direction orthogonal to the plane of the drawing in FIG. 1) is set to a value larger than the width of the substrate 500 so that the substrate 500 can pass therethrough. Moreover, the height of the substrate carrying port 111 and the substrate carrying port 112 (the length in the vertical direction of the paper surface in FIG. 1) is set to be sufficiently larger than the thickness of the substrate 500. For example, the height of the substrate carrying inlet 111 and the substrate carrying opening 112 is 5 to 20 mm. The substrate transfer port 111 and the substrate transfer port 112 are always open during the transfer of the substrate 500 from the substrate transfer port 111 to the substrate transfer port 112, for example.

The transport device 120 transports the substrate 500 from the substrate transfer port 111 toward the substrate transfer port 112. The conveying device 120 is, for example, a drum conveyor composed of a plurality of rollers 121. The plurality of rollers 121 are provided in parallel with each other at an appropriate interval in the transport direction of the substrate 500, and are matched with the heights of the substrate transfer port 111 and the substrate transfer port 112. The plurality of rollers 121 form a transport path that enters the inside of the etching bath 110 from the substrate transfer inlet 111 upstream of the substrate 500, and is carried out to the outside of the etching bath 110 through the substrate transfer port 112, and is sent to the substrate 500. The transport direction is downstream. The plurality of rollers 121 support the back surface 510 and transport the substrate 500. Therefore, the front surface 520 which will be described later does not contact the drum 121, and the front surface 520 is not damaged by the drum 121.

The plurality of rollers 121 are synchronously rotated by a drive control mechanism (not shown). When the plurality of rollers 121 are rotated in the same direction (clockwise in FIG. 1), the substrate 500 is horizontally transported from the substrate loading port 111 toward the substrate carrying port. Further, the conveying device 120 is not limited to the drum conveyor, and may be realized by a mechanism such as a belt conveyor or a robot arm.

The nozzle 130 blows a reaction gas to one surface (for example, the back surface 510) of the substrate 500 conveyed by the transfer device 120. The nozzle 130 is disposed inside the etching bath 110.

Hereinafter, the detailed structure of the nozzle 130 will be described with reference to Figs. 1 to 3 .

The nozzle 130 includes, for example, a gas supply path 132, a first gas suction path 133, and a second gas suction path 134 as shown in FIG. 2 . The upper end of the nozzle 130 is planar. At the upper end of the nozzle 130, an air outlet 132a of the gas supply path 132, a first suction port 133a of the first gas suction path 133, and a second suction port 134a of the second gas suction path 134 are provided. The first suction port 133a is provided between the air outlet 132a and the substrate carrying port 111, and the second suction port 134a is provided between the air outlet 132a and the substrate carrying port 112. The gas supply path 132, the first gas suction path 133, and the second gas suction path 134 have the same cross section in the direction orthogonal to the plane of the drawing of FIG. The air outlet 132a, the first suction port 133a, and the second suction port 134a have a slit shape extending in a direction orthogonal to the plane of the paper of Fig. 2 . The width of the air outlet 132a, the first suction port 133a, and the second suction port 134a (the length in the direction orthogonal to the plane of the paper in FIG. 2) is designed to be roughened over the entire surface 510 of the substrate 500. A number is greater than the width of the substrate 500.

The gas supply path 132 is connected to a reaction gas generating device (not shown) provided outside the etching bath 110. The reaction gas generating device generates a reaction gas from the material gas, and supplies the reaction gas to the gas supply path 132. Further, a raw material gas supply unit (not shown) is provided in the reaction gas generating device. The material gas supply unit supplies a raw material of the reaction gas, that is, a material gas. The raw material gas system contains, for example, a fluorine-based source gas and a carrier gas.

The fluorine-based raw material gas system is used to generate a fluorine-based reaction component that reacts with the surface of the substrate 500. The fluorine-based reaction component can be produced by introducing a fluorine-based source gas and water molecules into a plasma to cause a reaction. The carrier gas system is used to carry out the transfer and dilution of the fluorine-based raw material gas or to perform plasma discharge. In the present embodiment, CF _{4 is} used as the fluorine-based source gas, and alcohol is used as the carrier gas. Further, the following description will be made using hydrogen fluoride (HF) as an example of a fluorine-based reaction component. Further, the fluorine-based source gas is not limited thereto, and other perfluorocarbons such as C ₂ F ₆ and C ₃ F ₈ may be used, and hydrofluorocarbons such as CHF ₃ , CH ₂ F ₂ and CH ₃ F, SF ₆ and NF _{3 may be used.} Other fluorine-containing compounds such as XeF ₂ . Further, the carrier gas is not limited thereto, and other inert gases such as helium, neon or xenon may be used.

The material gas contains, for example, water vapor. In the present embodiment, the material gas supply unit includes a water addition unit that adds water to CF ₄ and alcohol. The water addition unit is, for example, a humidifier that supplies liquid water as saturated steam. The amount of water added can be adjusted by the temperature adjustment of the humidifier. The water vapor partial pressure in the material gas can be set by adjusting the amount of water added. Thereby, the condensation temperature of the fluorine-based reaction component and the water vapor generated in the plasma (that is, the temperature at which the hydrofluoric acid which causes the reaction with the substrate is formed) can be changed.

A plasma generating unit (not shown) connected to the material gas supply unit is provided in the reaction gas forming device. The plasma generating portion includes a pair of electrodes. The pair of electrodes are disposed via a passage for supplying the material gas. One of the pair of electrodes is connected to the power source and the other is grounded. By applying a high voltage from the power source, an electric field is generated between the pair of electrodes to discharge. Thereby, a plasma is generated between the pair of electrodes, and the raw material gas is introduced into the plasma to react with CF ₄ and water molecules to generate hydrogen fluoride which reacts with the surface of the substrate 500. That is, the raw material gas is introduced into the plasma to become a reaction gas. The reaction gas system is blown from the air outlet 132a to the back surface 510 of the substrate 500.

The top plate 135 is disposed above the nozzle 130 horizontally opposite to the upper end of the nozzle 130 as shown in FIGS. 1 to 3. After the substrate 500 is carried in from the substrate carrying inlet 111, it passes between the upper end of the nozzle 130 and the lower surface of the top plate 135, and is carried out from the substrate carrying opening 112. The distance between the upper end of the nozzle 130 and the lower surface of the top plate 135 is substantially equal to the thickness of the substrate carrying inlet 111 and the substrate carrying opening 112 (the length in the vertical direction of the paper surface in FIG. 1) so that the substrate 500 can pass therethrough.

While the substrate 500 passes between the upper end of the nozzle 130 and the lower surface of the top plate 135, the reaction gas blown from the air outlet 132a fills the gap 131 between the back surface 510 of the substrate 500 and the nozzle 130 (see FIG. 2). The back surface 510 is roughened while the back surface 510 is exposed to the reaction gas.

The arithmetic mean surface roughness of the back surface 510 is preferably from 0.3 to 1.5 nm. When the arithmetic mean surface roughness is 0.3 nm or more, it is difficult to produce a peeling tape when the substrate 500 is peeled off from the stage. Electricity. When the arithmetic mean surface roughness is 1.5 nm or less, the roughening treatment does not take time, and the in-plane strength of the substrate 500 is not insufficient.

A flat heater (not shown) that freely adjusts the temperature is provided on the lower surface of the top plate 135. By the heater, a region on the side opposite to the back surface 510 of the substrate 500 (hereinafter referred to as "front surface 520") which is located immediately below the top plate 135 can be heated. The width of the heater (as shown in Fig. 2 in the direction orthogonal to the plane of the paper) is such that the entire surface of the front surface 520 of the substrate 500 can be warmed, a number of which is greater than the width of the substrate 500. When the back surface 510 is defined as the first surface, the front surface 520 on the opposite side to the first surface is defined as the second surface.

The temperature at which the substrate 500 is carried into the etching bath 110 and the temperature of the heater of the top plate 135 are appropriately set in accordance with the condensation temperature of hydrogen fluoride and water vapor. Thereby, while the substrate 500 is passing through the top plate 135, the temperature of the back surface 510 can be set to be equal to or lower than the condensation temperature, and the temperature of the front surface 520 can be set to be equal to or higher than the condensation temperature. Therefore, hydrogen fluoride and water vapor condense only on the back surface 510 to form hydrofluoric acid. Thereby, even if one part of the reaction gas blown out from the air outlet 132a enters the gap between the top plate 135 and the front surface 520, the substrate 500 can be selectively etched only on the back surface 510. Therefore, the front surface 520 forming the electronic component or wiring can be kept smooth without being roughened.

The first gas suction path 133 and the second gas suction path 134 are external to the etching bath 110 and are connected to the gas recovery device 600 (see FIG. 1). The gas recovery device 600 includes a general suction mechanism, such as a rotary pump. The reaction gas supplied to the gap 131 is sucked from the first suction port 133a and the second gas suction port 134a, and is passed through the first gas suction path 133 and the second gas suction path 134 by the gas recovery device 600. Recycling.

Hereinafter, the air flow control device 140 will be described with reference to Figs. 1, 3, and 4.

The air flow control device 140 is disposed inside the etching bath 110 as shown in FIG. The airflow control device 140 suppresses the gap 131 between the surface of one side of the substrate 500 (in the present embodiment, the back surface 510) and the nozzle 130 from the outside of the substrate carrying port 111 and the substrate carrying port 112 into the etching bath 110 (see FIG. 2). . As shown in FIG. 1, the airflow control device 140 includes, for example, The first ventilation path 141 and the second ventilation path 142.

The first ventilation path 141 has a first vent 141c between the substrate carrying inlet 111 and the nozzle 130. As shown in FIG. 4( a ), the first air vent 141 flows in the outside air flowing into the etching groove 110 from the substrate carrying inlet 111 toward the gap 131 from the first air vent 141 c. Thereby, the first air passage 141 suppresses the inflow of the outside air flowing into the inside of the etching bath 110 from the substrate carrying inlet 111 into the gap 131.

As shown in FIG. 1 , the first ventilation path 141 includes, for example, a first back panel 141 a and a first front panel 141 b in the vicinity of the nozzle 130 . The first back panel 141a and the first front panel 141b are disposed, for example, at intervals of 50 to 100 mm. The first back panel 141a and the first front panel 141b are connected by a first side panel (not shown). The width of the first back panel 141a and the first front panel 141b is somewhat longer than the width of the substrate 500. The upper portion of the space surrounded by the first back panel 141a, the first front panel 141b, and the first side panel is open, and the open upper space becomes the first vent 141c.

As shown in FIG. 3, the first back panel 141a, the first front panel 141b, and the first side panel are disposed from the bottom surface of the etching tank 110 to the vicinity of the drum 121 as viewed from the substrate carrying inlet 111. The height. Thereby, the first air passage 141 functions as a shielding mechanism that shields the outside air from flowing into the gap 131 from the substrate loading port 111. The height of the first front panel 141b is lower than that of the first back panel 141a. Thereby, the first air passage 141 has a long box shape in the width direction of the opening of the first air vent 141c toward the substrate carrying inlet 111 side. Therefore, the outside air that has flowed in from the substrate carrying inlet 111 is more likely to flow into the first vent 141c.

As shown in FIG. 1, the upper end portion of the first back plate 141a is provided, for example, so as to enter between the adjacent two sets of the rollers 121. The upper end portion of the first back surface plate 141a is disposed at a position as high as possible without interfering with the range of the substrate 500 conveyed by the transport device 120. Thereby, it is possible to suppress the outside air flowing into the etching groove 110 from the substrate carrying inlet 111 from flowing into the gap 131. For example, the distance between the back surface 510 of the substrate 500 and the upper end portion of the first back surface plate 141a is 1 to 10 The mode setting of mm. The upper end position of the first front panel 141b is set, for example, at a position 50 to 100 mm lower than the position of the upper end portion of the first back panel 141a.

The first exhaust port 143 is open at the bottom surface of the etching groove 110 where the first ventilation path 141 is provided. The first exhaust port 143 is, for example, a slit shape in the width direction of the first air passage 141, but the shape of the first exhaust port 143 is not limited thereto.

The second ventilation path 142 has a second air vent 142c between the substrate carrying port 112 and the nozzle 130. As shown in FIG. 4( a ), the second air passage 142 allows the outside air flowing into the etching tank 110 from the substrate carrying port 112 toward the gap 131 to flow in from the second air vent 142 c. Thereby, the second air passage 142 suppresses the inflow of the outside air flowing into the inside of the etching bath 110 from the substrate carrying port 112 into the gap 131.

As shown in FIG. 1 , the second ventilation path 142 includes, for example, a second back panel 142 a and a second front panel 142 b in the vicinity of the nozzle 130 . The second back panel 142a and the second front panel 142b are disposed, for example, at intervals of 50 to 100 mm. The second back panel 142a and the second front panel 142b are connected by a second side panel (not shown). The width of the second back panel 142a and the second front panel 142b is somewhat longer than the width of the substrate 500. The upper portion of the space surrounded by the second back panel 142a, the second front panel 142b, and the second side panel is open, and the open upper space becomes the second vent 142c.

As shown in FIG. 3, the second back panel 142a, the second front panel 142b, and the second side panel are viewed from the substrate carrying opening 112, and are disposed from the bottom surface of the etching groove 110 to the vicinity of the roller so as to block the front of the nozzle 130. The height of 121. Thereby, the second air passage 142 functions as a shielding mechanism that shields the outside air from flowing into the gap 131 from the substrate carrying port 112. The second front panel 142b has a lower height than the second back panel 142a. Thereby, the second air passage 142 has a long box shape in the width direction of the opening of the second air vent 142c toward the substrate carrying port 112 side. Therefore, the outside air that has flowed in from the substrate carrying port 112 is more likely to flow into the second vent 142c.

As shown in FIG. 1, the upper end portion of the second back panel 142a is, for example, a group of two adjacent rollers. It is provided in the manner of the tube 121. The upper end portion of the second back plate 142a is disposed at a position as high as possible without interfering with the range of the substrate 500 conveyed by the transfer device 120. Thereby, it is possible to suppress the outside air flowing into the etching groove 110 from the substrate carrying port 112 from flowing into the gap 131. For example, the distance between the back surface 510 of the substrate 500 and the upper end portion of the second back surface plate 142a is set to be 1 to 10 mm. The upper end position of the second front panel 142b is set, for example, at a position 50 to 100 mm lower than the position of the upper end portion of the second back panel 142a.

The second exhaust port 144 is open at the bottom surface of the etching groove 110 where the second ventilation path 142 is provided. The second exhaust port 144 is, for example, a slit shape in the width direction of the second air passage 142, but the shape of the second exhaust port 144 is not limited thereto.

The first ventilation path 141 and the second ventilation path 142 are connected as shown in FIG. 1 , for example, outside the etching groove 110 by a connection path 150 . The connecting path 150 penetrates the internal space of the first ventilation path 141 and the second through the first exhaust port 143 disposed at the bottom of the first ventilation path 141 and the second exhaust port 144 disposed at the bottom of the second ventilation path 142. The internal space of the ventilation path 142.

The first ventilation path 141, the connection path 150, and the second ventilation path 142 form a bypass path for bypassing the outside air toward the gap 131. The outside air that has flowed into the inside of the etching bath 110 from the substrate loading port 111 or the substrate carrying port 112 flows out through the bypass path on the substrate carrying port 112 side or the substrate carrying port 111 side. Therefore, the outside air flowing into the inside of the etching bath 110 is prevented from flowing directly into the gap 131.

A suction device 160 is connected to the connection path 150. Suction device 160 includes a general suction mechanism, such as a rotary pump. By operating the suction device 160, the internal gas of the connection path 150 can be discharged, and the gases inside the first ventilation path 141 and the second ventilation path 142 can be discharged. It is not necessary to continuously operate the suction device 160, and when the outside air flowing into the etching bath 110 is large, it is necessary to operate it as needed.

Hereinafter, the configuration of the substrate manufacturing system 1000 including the etching apparatus 100 will be described with reference to FIG. 5. FIG. 5 is a side view showing a portion of the substrate manufacturing system 1000. In Figure 5, the symbol No. 1030 corresponds to the etching bath 110 shown in FIG. In FIG. 5, the symbols shown in FIG. 1 are collectively indicated by the symbols constituting the constituent elements of the etching bath 1030.

The substrate manufacturing system 1000 includes a first cleaning tank 1010, a first buffer tank 1020, an etching tank 1030, a second buffer tank 1040, a second cleaning tank 1050, and a conveying device 1070.

The conveying device 1070 conveys the substrate 500 from the left side of the drawing to the right side of the drawing. The conveying device 1070 is, for example, a drum conveyor composed of a plurality of rollers 1071. The plurality of rollers 1071 form a transport path that sequentially passes through the first cleaning tank 1010, the first buffer tank 1020, the etching tank 1030, the second buffer tank 1040, and the second from the upstream side of the first cleaning tank 1010. The cleaning tank 1050 is sent to the downstream side of the second cleaning tank 1050.

Although not shown in the drawings, on the upstream side of the first cleaning tank 1010, for example, a device for forming or polishing the substrate 500 is provided. On the downstream side of the second cleaning tank 1050, for example, means for performing drying or inspection of the substrate 500 is provided.

The first cleaning tank 1010, the first buffer tank 1020, the second buffer tank 1040, and the second cleaning tank 1050 each include a substrate transfer port and a substrate transfer port. The substrate transfer port and the substrate transfer port of each groove are the same height and the same size as the substrate transfer port 1031 and the substrate transfer port 1032 of the etching bath 1030. The substrate transfer ports of the respective grooves are sequentially connected to the substrate transfer inlets of the grooves adjacent to the downstream side in the transfer direction.

Hereinafter, the manufacturing process of the substrate 500 will be described using FIG.

After the substrate 500 is formed into a strip shape by a floating method, for example, a cutting step of cutting the substrate 500 to a desired size, a chamfering step of chamfering the end surface of the substrate 500, and a surface of the polishing substrate 500 (front surface 520) The polishing process is carried to the first cleaning tank 1010. As the polishing method, for example, a method of supplying a slurry to a substrate for polishing is used. The slurry is a dispersion in which abrasive particles are dispersed in a liquid of water or an organic solvent. As the abrasive particles, for example, cerium oxide is used.

The polished substrate 500 is transferred to the first cleaning tank 1010 by the conveying device 1070. In the first cleaning bath 1010, abrasive particles are removed from the surface of the substrate 500. For the first cleaning In the tank 1010, for example, the substrate 500 is first washed by washing, and the abrasive particles on the surface of the substrate 500 are washed away with water. Thereafter, the substrate 500 is washed with a slurry. In the slurry cleaning, the cleaning slurry is blown from the nozzle to the substrate, and a cleaning mechanism such as a circular brush is used to remove the cleaning method of the abrasive particles that cannot be removed by the shower cleaning. As the cleaning slurry, for example, a dispersion obtained by dispersing cerium oxide, calcium carbonate, or magnesium carbonate in a liquid of an organic solvent is used.

The substrate 500 is carried out from the first cleaning tank 1010 by the conveying device 1070, and is carried into the first buffer tank 1020. The first buffer tank 1020 is provided to prevent the reaction gas from leaking from the substrate carrying inlet 1031 to the first cleaning tank 1010. Thereby, the cleaning step performed in the first cleaning tank 1010 is not contaminated by the reaction gas.

The first buffer tank 1020 has, for example, a fan filter unit FFU1 on the top plate and an exhaust port EXH1 on the bottom plate. The fan filter unit FFU1 filters the outside air and introduces it into the inside of the first buffer tank 1020, and sets the inside of the first buffer tank 1020 to a positive pressure state. The outside air introduced by the fan filter unit FFU1 is discharged from the exhaust port EXH1 to the outside of the first buffer tank 1020 having a relatively low pressure together with the dust or gas inside the first buffer tank 1020.

The substrate 500 is carried out from the first buffer tank 1020 by the transport device 1070, and is carried into the etching bath 1030. In the etching bath 1030, the reaction gas is blown from the nozzle 1080 (130 in FIG. 1) on the back surface 510 of the substrate 500, and the back surface 510 of the substrate 500 is roughened.

The roughened substrate 500 is carried out from the etching bath 1030 by the transfer device 1070, and is carried into the second buffer tank 1040. The second buffer tank 1040 is provided to prevent the reaction gas from leaking from the substrate discharge port 1032 to the second cleaning tank 1050. Thereby, the washing step performed in the second washing tank 1050 is not contaminated by the reaction gas.

The second buffer tank 1040 has, for example, a fan filter unit FFU2 on the top plate and an exhaust port EXH2 on the bottom plate. The fan filter unit FFU2 filters the outside air and introduces it into the inside of the second buffer tank 1040, and sets the inside of the second buffer tank 1040 to a positive pressure state. The outside air introduced by the fan filter unit FFU2 is discharged from the exhaust port EXH2 to the outside of the first buffer tank 1020 having a relatively low pressure together with the dust or gas inside the second buffer tank 1040.

The substrate 500 is carried out from the second buffer tank 1040 by the transport device 1070, and is carried into the second cleaning tank 1050. The second cleaning tank 1050 includes a high pressure shower 1051. In the second cleaning bath 1050, both surfaces of the substrate 500 are cleaned, and glass swarf generated by roughening, etching-derived products, and the like are removed. The cleaning method is not particularly limited, and examples thereof include high pressure shower cleaning, brushing, ultrasonic cleaning, or the like. The cleaned substrate 500 is carried out from the second cleaning tank 1050 by the conveying device 1070, and is supplied to a drying step or a detecting step.

Hereinafter, the function of the airflow control device 140 will be described using Figs. 4 to 6 . FIG. 6 is a view showing a distribution of gas fluctuations around the nozzle 1080 when the etching bath 1030 does not include the air flow control device 140.

As shown in FIG. 4(a), the back surface 510 of the substrate 500 is roughened by the reaction gas blown from the nozzle 130. The thickness of each portion in the back surface 510 of the substrate 500 is determined by the concentration of the reaction gas exposed at the portion thereof and the cumulative time at which the portion is exposed to the reaction gas. These factors greatly vary due to airflow disturbances generated by the gap 131 between the substrate 500 and the nozzles 130. The airflow disturbance is caused by the outside air flowing into the inside of the etching bath 110 through the substrate carrying port 111 and the substrate carrying port 112.

The inflow of the outside air is caused by a pressure difference between the first buffer tank 1020 and the second buffer tank 1040 shown in FIG. As will be apparent from the inventors' investigation, especially when the size of the substrate 500 is large enough to span the length of a plurality of grooves, the pressure difference is remarkably generated. Moreover, it has been clarified by the inventors that the degree of inflow of outside air varies with time due to the conveyance of the substrate 500.

The reason why a pressure difference is generated between the first buffer tank 1020 and the second buffer tank 1040 is considered to be various. For example, the difference between the first cleaning tank 1010 and the second cleaning tank 1050 is one of the possible causes.

In the first cleaning tank 1010, for example, shower cleaning and slurry cleaning are performed before the substrate 500 is carried out. However, even if the devices are activated, the air pressure distribution throughout the first cleaning tank 1010 does not vary greatly. On the other hand, when the substrate 500 is moved into the second clear When the tank 1050 is washed, high pressure shower cleaning is performed by the high pressure shower 1051. When the high pressure shower 1051 is actuated, the gas distribution in the entire interior of the second cleaning tank 1050 is greatly changed. The fluctuation is changed by the substrate inlet of the second cleaning tank 1050, and the pressure inside the adjacent second buffer tank 1040 is varied. Particularly in the case where the size of the substrate 500 is large, a state in which the substrate 500 straddles from the etching groove 1030 to the second cleaning bath 1050 is generated. In this case, during the roughening of one portion of the substrate 500 in the etching bath 1030, another portion of the substrate 500 is subjected to high pressure showering in the second cleaning bath 1050, thereby generating pressure during roughening. Change, and the inflow of outside air. Such a situation occurs when the length of the substrate 500 is the length from the nozzle 1080 to the substrate transfer inlet of the second cleaning tank 1050 in the transport direction of the substrate 500.

A pressure difference is generated between the first buffer tank 1020 and the second buffer tank 1040, and other reasons may also be considered.

For example, as shown in FIG. 6, when the size of the substrate 500 is large, the air pressure of the first buffer tank 1020 and the second buffer tank 1040 differs depending on the relative positions of the substrate 500 and the etching bath 1030. As a result, a pressure distribution is generated inside the etching bath 1030, and an air flow is generated before and after the nozzle 1080. The substrate 500 having a large size refers to a length from the air outlet 132a of the nozzle 1080 to the substrate loading port of the first buffer tank 1020 in the transport direction of the substrate 500, or from the air outlet 132a to the second of the nozzle 1080. The substrate of the buffer tank 1040 has a length greater than or equal to the length of the substrate.

For example, as shown in FIG. 6(a), when the front end portion of the substrate 500 reaches the vicinity of the nozzle 1080, the first buffer tank 1020 is divided into upper and lower spaces by the substrate 500. At this time, the outside air is introduced by the fan filter unit FFU1, and the space above the first buffer tank 1020 becomes a positive pressure. Since the introduced outside air is blocked by the substrate 500, the space on the lower side of the first buffer tank 1020 becomes a negative pressure. On the other hand, the second buffer tank 1040 introduces outside air through the fan filter unit FFU2, and the entire space becomes a positive pressure. The etching bath 1030 divides a space between the substrate carrying inlet 1031 and the nozzle 1080 by the substrate 500. Due to the underside of the substrate 500 The space is connected to the substrate transfer inlet 1031 via the space below the first buffer tank 1020, and thus is a negative pressure. On the other hand, since the space between the nozzle 1080 and the substrate transfer port 1032 is connected to the substrate transfer port 1032 via the entire space of the second buffer tank 1040, it becomes a positive pressure. As a result, inside the etching bath 1030, a gas flow from the substrate carrying port 1032 toward the substrate carrying port 1031 is generated.

As shown in FIG. 6(c), when the rear end portion of the substrate 500 is transported to the vicinity of the nozzle 1080, since the substrate 500 does not exist in the first buffer tank 1020, the outside air is introduced through the fan filter unit FFU1, and the first buffer tank is introduced. The entire space of 1020 becomes positive pressure. On the other hand, the second buffer tank 1040 is divided into upper and lower spaces by the substrate 500. At this time, the outside air is introduced by the fan filter unit FFU2, and the space above the second buffer tank 1040 becomes a positive pressure. Since the introduced outside air is blocked by the substrate 500, the space on the lower side of the second buffer tank 1040 becomes a negative pressure. The etching bath 1030 partitions the space between the nozzle 1080 and the substrate carrying port 1032 by the substrate 500. Since the space on the lower side of the substrate 500 is connected to the substrate carry-out port 1032 via the space on the lower side of the second buffer tank 1040, it becomes a negative pressure. On the other hand, since the space between the nozzle 1080 and the substrate transfer opening 1031 is connected to the substrate transfer inlet 1031 through the entire space of the first buffer tank 1020, it becomes a positive pressure. As a result, an air flow from the substrate carrying inlet 1031 toward the substrate carrying port 1032 is generated inside the etching bath 1030.

Further, as shown in FIG. 6(b), in the middle of transporting the substrate 500 from the substrate loading port 1031 to the substrate carrying port 1032, depending on whether or not the substrate 500 separates the spaces of the first buffer tank 1020 and the second buffer tank 1040, Achieve various pressure distributions.

As described above, particularly in the case of using a substrate of a larger size, depending on the relative position of the substrate 500 and the etching groove 1030, a different pressure distribution is generated before and after the nozzle 1080 in the etching groove 1030. Since the plurality of substrates 500 are sequentially and continuously transported through the substrate transfer port 1031 and the substrate transfer port 1032, the pressure difference between the nozzles 1080 and the like changes with time.

As shown in FIG. 4(b), the airflow control device 140 is not disposed in the etching bath 110. At the time, the outside air that has flowed in from the substrate carrying inlet 111 and the substrate carrying opening 112 is hardly blocked, and reaches the gap 131 between the back surface 510 of the substrate 500 and the nozzle 130. Therefore, the concentration distribution of the reaction gas filled in the gap 131 is directly affected by the disturbance of the gas flow. As a result, the thickness of the back surface 510 of the substrate 500 produces unevenness.

On the other hand, as shown in FIG. 4(a), when the airflow control device 140 is provided in the etching bath 110, the outside air that has flowed in from the substrate carrying inlet 111 and the substrate carrying port 112 flows into the first ventilation path. 141. The bypass path formed by the connection path 150 and the second ventilation path 142 is prevented from directly reaching the gap 131. Moreover, since the pressure inside the first ventilation path 141 and the second ventilation path 142 is always equal pressure by the connection path 150, the time difference between the first buffer tank 1020 and the second buffer tank 1040 is also moderated. The impact of changes. Thereby, the concentration distribution of the reaction gas filled in the gap 131 is hardly affected by the airflow interference, thereby increasing the roughness uniformity of the back surface 510 of the substrate 500.

Further, when the suction device 160 is operated, the internal pressure of the connection path 150 is maintained at a negative pressure for a long time (for example, -1 to -2 Pa). Thereby, even if a pressure difference (for example, a maximum of ±3 Pa) occurs between the first buffer tank 1020 and the second buffer tank 1040, the flow of the outside air occurs almost between the substrate carrying port 111 and the first vent 141c, and Between the substrate carrying outlet 112 and the second vent 142c. Therefore, in the gap 131 between the back surface 510 of the substrate 500 and the nozzle 130, the influence of the inflow of the outside air is lowered. Further, since the first vent 141c and the second vent 142c are opened toward the side opposite to the nozzle 130, the airflow of the gap 131 is not greatly disturbed by operating the suction device 160.

As described above, in the etching apparatus of the present embodiment, as shown in FIG. 4(a), the substrate transfer port 111 having the etching groove 110 having the substrate transfer port 111 and the substrate transfer port 112 is transferred to the substrate transfer port 112. 500, and the reaction gas is blown from the nozzle 130 to the back surface 510 of the substrate 500. The blowing system of the reaction gas is prevented from flowing into the gap 131 between the back surface 510 of the substrate 500 and the nozzle 130 from the substrate carrying port 111 and the substrate carrying port 112 into the gap 131 between the back surface 510 of the substrate 500 and the nozzle 130.

For example, in order to prevent the outside air flowing into the etching groove 110 from the substrate carrying inlet 111 from flowing into the gap 131, as shown in FIG. 4(a), the outside air flowing into the etching groove 110 from the substrate carrying port 111 toward the gap 131 is set. The first vent 141c between the substrate carrying inlet 111 and the nozzle 130 flows into the first air passage 141.

In order to prevent the outside air flowing into the etching groove 110 from the substrate carrying port 112 from flowing into the gap 131, as shown in FIG. 4(a), the outside air flowing into the etching groove 110 from the substrate carrying port 112 toward the gap 131 is provided on the substrate. The second vent 142c between the outlet 112 and the nozzle 130 flows into the second ventilation path 142.

Therefore, it is possible to suppress the thickness unevenness on the back surface 510 of the substrate 500 which occurs as the outside air flows into the inside of the etching bath 110.

The preferred embodiments of the present invention have been described above with reference to the drawings, but the present invention is not limited to the above examples. The shapes and combinations of the constituent members shown in the above examples are merely examples, and various modifications can be made based on design requirements and the like without departing from the spirit of the invention.

For example, in the above embodiment, the first ventilation path 141 and the second ventilation path 142 are connected to the common suction device 160, but the first ventilation path 141 and the second ventilation path 142 may be respectively connected to different suctions. Device. In this case, the outside air that has flowed into the inside of the etching bath 110 from the substrate carrying inlet 111 and the outside air that has flowed into the inside of the etching bath 110 from the substrate carrying port 112 are independently discharged. Even in this case, the outside air flowing into the inside of the etching bath 110 can be prevented from flowing into the gap 131 between the back surface 510 of the substrate 500 and the nozzle 130. As a result, the thickness unevenness in the back surface 510 of the substrate 500 can be suppressed.

Further, in the method for producing a substrate according to an aspect of the present invention, after forming into a strip shape by a float method or a melt method, the method includes: a cutting step of cutting the substrate 500 to a desired size; and pouring the end surface of the substrate 500 The corner chamfering step and the step of etching the back surface 510 by the etching method described in the above embodiment on the substrate 500 subjected to the polishing step of the surface (front surface 520) of the substrate 500. As a result, a basis for suppressing the thickness unevenness in the back surface 510 can be obtained. Board 500.

Further, in the substrate according to the embodiment of the present invention, the average value of the arithmetic mean surface roughness of the entire back surface 510 is 0.3 to 1.5 nm, and the average of the arithmetic mean surface roughness of the peripheral portion of the back surface 510 is opposite to the back surface 510. The arithmetic mean surface roughness of the central portion is different, and the standard deviation of the arithmetic mean surface roughness of the entire back surface 510 is 0.06 nm or less.

When the substrate 500 is divided into nine regions of three vertical and horizontal directions, the central portion thereof is defined as a central portion, and the region around the central portion other than the central portion is referred to as a peripheral portion. The peripheral portion is in the region of 500 mm from the edge. The average value of the arithmetic mean surface roughness of the peripheral portion is the average of the arithmetic mean surface roughness of the eight regions except the central portion. The arithmetic mean surface roughness of the central portion and the peripheral portion is not the same, but the deviation of the arithmetic mean surface roughness of the entire back surface 510 is represented by a standard deviation of 0.06 or less, thereby effectively suppressing the peeling charge amount and suppressing the cause Stripping damage caused by charging. Further, the arithmetic mean surface roughness of the central portion may be higher than the arithmetic mean surface roughness of the peripheral portion.

In addition, the larger the size of the substrate, the more the possibility of damage to the substrate caused by the peeling electrification when placed on the vacuum suction platform for a certain period of time. Therefore, in the substrate according to the embodiment of the present invention, since the substrate size is 1500 mm × 1500 mm or more, the effect of suppressing the peeling charge amount is preferable, which is preferable. Further, if the substrate size is 2000 mm × 2000 mm or more, the effect is further improved.

In addition, when the value of the arithmetic mean surface roughness of the center portion of the back surface 510 minus the average value of the arithmetic mean surface roughness of the entire back surface 510 is -0.13 or more and 0.13 or less, the peeling charge amount can be more effectively suppressed.

[Examples]

Hereinafter, an embodiment of the present invention will be described using Figs. 7 to 9 . Fig. 7 is a view showing a numerical simulation calculation model relating to a concentration distribution of a reaction gas and an example of calculation results. Fig. 8 and Fig. 9 are graphs showing the pressure dependence of numerical simulation results relating to the concentration distribution of the reaction gas.

Fig. 7 is a calculation model showing numerical simulation relating to the concentration distribution of the reaction gas. Here, a simulation calculation of the flow of the reaction gas in the nozzle and the gap is performed. As a calculation software, fluid calculation was performed by a direct method using ANSYS (registered trademark) (product name: ANSYS FLUENT, version: 14.5, manufactured by ANSYS, Inc.).

Figure 7(a) shows a computational model of the space 700 below the substrate 750 in the etched trench. In the calculation of the embodiment, a first ventilation path (air flow control device) 741 is provided on the upstream side (left and right of the drawing) in the transport direction of the substrate 750 with respect to the nozzle 730, and a second ventilation path is provided on the downstream side (right side) (air flow control) Device) 742. In the calculation of the comparative example, the first ventilation path 741 and the second ventilation path 742 are not provided.

The boundary conditions as pressure related are set as follows. The pressure of the substrate transfer inlet 711 is equal to the pressure P _{LD of the} first buffer tank. The pressure of the substrate transfer port 712 is equal to the air pressure P _{NT of the} second buffer tank. The pressure inside the first ventilation path 741 and the second ventilation path 742 is equal to the air pressure of the connection path (suction pressure of the suction device) P _BB .

Fig. 7(b) shows the gap between the amplification nozzle 730 and the substrate 750 in the simulation space. In the simulation calculation, the size d _{A of the air} outlet 732a is set to 2 mm, the size d _{B of the} first suction port 733a is set to 7 to 10 mm, and the size d _{C of the} second suction port 734a is set to 7~. 10mm. Further, the interval d _{D of the} gap 731 is set to 2 to 5 mm. Further, the outlet 732a of the center to boast a first suction mouth 733a of the center distance I ₁ is set to 70mm, the center 734a of the boast from the center to the outlet 732a of the second suction port I ₂ is set to 70mm. The mesh size is in the range of 0.1 to 4 mm, and the value suitable for the position within each simulation space is selected.

Regarding the parameters d _B , d _C , and d _D , a plurality of them are selected within the above range, and each value is calculated. However, the conclusion that the coarseness uniformity is improved by using the airflow control device and the conclusion that the coarseness uniformity can be further improved by operating the suction device. In Figs. 8 and 9, the calculation results when d _B = 7 mm, d _C = 10 mm, and d _D = 4 mm are set.

The reaction gas is blown out from the air outlet 732a to the gap 731 through the gas supply path 732. The reaction gas system is sucked from the first suction port 733a toward the first gas suction path 733. Again The gas system is sucked from the second suction port 734a toward the second gas suction path 734. In order to express this condition, a boundary condition in which the inflow velocity of the reaction gas in the gas passage path 732 is a constant value is set. Further, a boundary condition in which the internal pressure of each of the first gas suction path 733 and the second gas suction path 734 is a constant value is set. In the present simulation calculation, the reaction gas inflow velocity of the gas supply path 732 was set to 0.07 m/s. Further, the internal pressure of the first gas suction path 733 was set to -1.9 Pa, and the internal pressure of the second gas suction path 734 was set to -1.9 Pa.

In the gap 731, the substrate 750 is transported from left to right (in the direction of the arrow shown in FIG. 7(b)). In order to express this, the back surface 751 of the substrate 750 is set to have a moving boundary condition of a certain speed in the right direction. In this simulation calculation, the moving speed of the back surface 751 of the substrate 750 was set to 167 mm/s.

The concentration distribution of the reaction gas in the gap 731 is calculated by changing the conditions. The conditions of the change are the air pressure P _LD of the first buffer tank, the air pressure P _{NT of the} second buffer tank, and the air pressure of the connection path (suction pressure of the suction device) P _BB .

With respect to the given P _BB , it was tried to change the combination of several kinds of P _LD and P _{NT to} investigate how the concentration distribution of the reaction gas in the gap 731, especially the maximum value, changes. It is considered that the difference between P _LD and P _NT corresponds to the magnitude of the external air flow flowing into the etching bath. Therefore, according to the simulation, the degree of sensitivity of the concentration distribution of the reaction gas in the gap 731 to the inflow of the outside air can be grasped.

The thickness of the back surface 751 of the substrate 750 is determined by the concentration of the reaction gas exposed on the back surface 751 of the substrate 750 and the cumulative time of exposure to the reaction gas. The accumulation time is mainly determined by the speed at which the substrate 750 is transferred. In the simulation calculation, as described above, the speed at which the substrate 750 is transferred is set to a constant value of 167 mm/s. Therefore, the thickness of the back surface 751 of the substrate 750 is mainly determined by the maximum value of the concentration distribution (the thickness increases as the maximum value increases). Therefore, according to the simulation, it is understood that the thickness of the back surface 751 of the substrate 750 is affected by the inflow of external air.

Fig. 8(a) shows an example of the result of calculating the concentration distribution of the reaction gas in the gap 731 in the above comparative example of the introduction of the gas flow control device. The horizontal axis (Position: position (m)) is the position inside the nozzle 730, and the vertical axis ([HF] (ppm)) is the concentration of the reaction gas. The position in the nozzle 730 is such that the blowing port 732a is used as the origin, the side of the first suction port 733a is set to be negative, and the side of the second suction port 734a is set to be a positive coordinate. The substrate 750 is transferred from the left to the right of the drawing, and the reaction gas is also affected by the substrate 750, and has a concentration distribution on the right side (Position>0) of the air outlet 732a.

Corresponding to each combination of P _LD and P _NT described above, a plurality of concentration distribution curves are obtained. An example is as follows.

Pm:P _LD =P _NT =0 Pa,pm_LD_0 pa_NT_-1 pa:P _LD =0 Pa,P _NT =-1 pa,pm_LD_1 pa_NT_0 pa:P _LD =1 Pa,P _NT =0 pa,pm_LD_1pa_NT_1 pa:P _LD =1 Pa, P _NT =1 pa, pm_LD_-1 pa_NT_-1 pa: P _LD =-1 Pa, P _NT =-1 pa, pm_NT_0 pa_LD_-1 pa: P _LD =-1 Pa, P _NT =0 Pa, pm_NT_1 pa_LD_0 pa: P _LD =0 Pa, P _NT =1 pa. It can be seen from Fig. 8(a) that there is a tendency that the peak value becomes higher when P _LD <P _NT and the peak value becomes lower when P _LD >P _NT . On the other hand, the position of the peak is hardly changed and exists in the vicinity of the second suction port 734a.

In the embodiment after the introduction of the air flow control device, when the combination of P _LD and P _{NT is} changed under the given P _BB , the magnitude of the peak height variation range (hereinafter referred to as "peak fluctuation range") is remarkable. The magnitude of the peak variation corresponds to the magnitude of the effect of external air inflow on the roughening of the substrate 750. The inventors have explored the relationship between P _BB and the peak variation range based on this simulation calculation.

8(b), (c), and (d) show an embodiment in which P _BB = -0.5 Pa, -1 Pa, -1.5 Pa (the etching apparatus provided with the air flow control device of the present invention) Calculation results. The horizontal axis and the vertical axis and the example are the same as in Fig. 8(a). In Figs. 8(a), (b), (c), and (d), the magnitudes of the peak fluctuation ranges were 272 ppm, 114 ppm, 75 ppm, and 23 ppm, respectively.

When the absolute value of P _BB is sequentially increased from zero, the peak fluctuation amplitude gradually decreases. This means that the influence of the inflow of outside air on the roughening of the substrate can be reduced by sucking the outside air flowing into the etching bath by the suction device.

Figure 9 is a graph showing the peaks of a plurality of concentration profiles obtained by changing the combination of P _LD and P _NT under the given P _BB . The horizontal axis (ΔP(Pa)) represents the difference between P _LD and P _NT (ΔP = P _{LD -} P _NT ). The vertical axis is the peak of each concentration distribution ([HF] _max (ppm)). For example, (P _LD , P _NT )=(-1 Pa, 0 Pa) and (P _LD , P _NT )=(0 Pa, +1 Pa), there is a different combination ΔP with respect to P _LD and P _NT Equal situation. Therefore, in Fig. 9, a plurality of (three points in Fig. 9) data points are plotted for the same value of ΔP. Fig. 9(a) shows the settlement result of the comparative example. 9(b), (c), and (d) show the calculation results of the examples in the case where PBB = -0.5 Pa, -1 Pa, -1.5 Pa. The serial numbers of the data points marked in the figure correspond to the following.

#1:(P _LD , P _NT )=(0 Pa, 0 Pa)

#2:(P _LD , P _NT )=(0 Pa, -1 Pa)

#3:(P _LD , P _NT )=(0 Pa, -0.5 Pa)

#4:(P _LD , P _NT )=(1 Pa, 0 Pa)

#5:(P _LD , P _NT )=(1 Pa, 1 Pa)

#6:(P _LD , P _NT )=(1 Pa, 0.5 Pa)

#7:(P _LD , P _NT )=(0.5 Pa, 0 Pa)

#8:(P _LD , P _NT )=(0.5 Pa, 0.5 Pa)

#9:(P _LD , P _NT )=(0.5 Pa, -0.5 Pa)

#10:(P _LD , P _NT )=(-1 Pa, -1 Pa)

#11:(P _LD , P _NT )=(-0.5 Pa, -0.5 Pa)

#12:(P _LD , P _NT )=(-1 Pa, 0 Pa)

#13:(P _LD , P _NT )=(-0.5 Pa, 0 Pa)

#14:(P _LD , P _NT )=(0 Pa, 1 Pa)

#15:(P _LD , P _NT )=(0.5 Pa, 1 Pa)

#16:(P _LD , P _NT )=(0 Pa, 0.5 Pa)

#17:(P _LD , P _NT )=(-0.5 Pa, 0.5 Pa)

#18:(P _LD , P _NT )=(0 Pa, 0 Pa)

As shown in FIG. 9, when the absolute value of P _BB increases from zero, the peaks are approximately equal. Therefore, when the suction device of the air flow control device of the present invention is used, the concentration distribution of the reaction gas in the gap can be stably distributed without being affected by the time variation of the pressures of the first buffer tank and the second buffer tank. This means that the roughness uniformity can be easily improved by operating the suction device.

Tables 1 and 2 show the results of measuring the in-plane distribution of the roughened substrate thickness (arithmetic average surface roughness Ra (JIS B0601-2013)) by atomic force microscopy. Table 1 shows the measurement results when the etching tank was not introduced into the gas flow control device of the present invention. Table 2 shows the measurement results in the case where the etching tank was introduced into the gas flow control device of the present invention. The production conditions are as follows. Etching groove size: 850 mm, substrate: alkali-free glass (product name: AN100, manufactured by Asahi Glass Co., Ltd.), substrate size: width 2880 mm × transport direction length 3130 mm, substrate transport speed: 10 m/min, reaction gas composition: CF ₄ , N _2. Water vapor, reaction gas ejection flow rate at the nozzle portion: 0.07 m/sec.

The measurement points are three rows in the width direction of the substrate, and nine points in total in three rows in the transport direction of the substrate. The measurement points are arranged in the width direction of the substrate, in the order of 500 mm from the leftmost end, at the center, and at the right end of 500 mm (hereinafter referred to as "1st line", "2nd line", "3rd" Row"). The measurement points are arranged in the direction in which the substrate is transported, and are arranged at a position 500 mm from the foremost end, at the center, and at a distance of 500 mm from the last end (hereinafter referred to as "first column", "second column", "third" Column").

The measurement was carried out in the following manner. First, a sample having a width of 5 mm × a length of 5 mm including each measurement point was cut out from the roughened substrate. Next, use an atomic force microscope Product Name: SPI-3800N, manufactured by Seiko Instruments Inc.) Observe the roughened surface of each sample. The cantilever uses the SI-DF40P2. The observation system was performed for a scanning area of 5 μm × 5 μm using a dynamic force model at a scan ratio of 1 Hz (number of data in the area: 256 × 256). Based on this observation, the arithmetic mean surface roughness Ra of each measurement point was calculated. The calculation software uses a software attached to an atomic force microscope (software name: SPA-400).

In Tables 1 and 2, the arithmetic mean surface roughness Ra (unit: nm) of each measurement point is shown in an array form. Each row of Table 1 and Table 2 sequentially corresponds to the first row, the second row, and the third row of the measurement point from the left. The columns of Tables 1 and 2 correspond to the first column, the second column, and the third column of the measurement points in order from the top.

As shown in Table 1, when the airflow control device is not introduced, the uniformity of the roughness is low, and the thickness of the central portion of the substrate is smaller than the average value. Specifically, the average value of Ra is 0.43, the standard deviation is 0.073, and the difference between Ra and the average value in the central portion of the substrate is -0.144. On the other hand, as shown in Table 2, in the case of introducing the air flow control device, both the uniformity of the thickness and the thickness of the central portion of the substrate can be improved. Specifically, the average value of Ra is 0.45, the standard deviation is 0.057, and the difference between Ra and the average value in the central portion of the substrate is +0.11.

The measurement of the peeling charge amount was carried out in the following manner. First, a sample having a width of 410 mm and a length of 510 mm was cut out from the roughened substrate. Next, the sample is placed in a vacuum pump Suction the platform for a certain period of time. From the above vacuum suction platform, the sample was peeled off using a lift pin. The amount of charge of the sample immediately after peeling was measured by a surface potentiometer (product name: MODEL 341B, manufactured by Trek Japan Co., Ltd.).

The measurement was performed on Examples, Comparative Example 1, and Comparative Example 2. The embodiment is a glass substrate which is roughened by using an etching apparatus including the air flow control device of the present invention. Comparative Example 1 is a glass substrate which is roughened using an etching apparatus which does not include the gas flow control device of the present invention. Comparative Example 2 is a commercially available glass substrate. The production conditions of the examples and comparative example 1 are as follows. Etching groove size: 850 mm, substrate: alkali-free glass (product name: AN100, manufactured by Asahi Glass Co., Ltd.), substrate size: width 2880 mm × transport direction length 3130 mm, substrate transport speed: 10 m/min, reaction gas composition: CF ₄ , N _2. Water vapor, reaction gas ejection flow rate at the nozzle portion: 0.07 m/sec.

The measured peeling charge amount was a relative comparative value, and was an example: Comparative Example 1: Comparative Example 2 = 0.84: 1.0: 0.91. The charge amount of the Example was lower than that of Comparative Example 1 and Comparative Example 2. As shown in Tables 1 and 2, this is because the roughening of the etching groove of the present invention is carried out to improve the uniformity of the roughening.

As shown in the above embodiment, according to the present invention, the concentration distribution of the reaction gas in the gap between the surface to be roughened and the nozzle of the substrate is not affected by the pressure fluctuation of the first buffer tank and the second buffer tank, but may be substantially Stable distribution. Thereby, the thickness unevenness of the back surface of the substrate can be suppressed. As a result, the amount of peeling electrification of the substrate can be reduced.

The present application is based on a Japanese patent application filed on Apr. 16, 2014, the entire disclosure of which is hereby incorporated by reference.

Claims (7)

An etching apparatus comprising: an etching tank having a substrate carrying inlet and a substrate carrying outlet; and a conveying device that transports the substrate from the substrate carrying inlet toward the substrate carrying outlet; and the nozzle is disposed inside the etching tank to discharge a reaction gas a surface of the substrate conveyed by the transfer device; and an air flow control device installed in the etching groove to prevent external air flowing into the etching groove from the substrate transfer port and the substrate transfer port from flowing into the substrate a gap between the nozzle and the nozzle; the airflow control device includes: a first air passage that allows external air to flow from the substrate inlet to the gap into the etching tank, and is disposed between the substrate inlet and the nozzle a first vent opening; and a second venting path for causing external air flowing into the etching tank from the substrate carrying port toward the gap, and flowing from a second vent provided between the substrate carrying port and the nozzle The nozzle includes a gas suction port for sucking the reaction gas The etching apparatus of claim 1, comprising a connection path connecting the first ventilation path and the second ventilation path. The etching apparatus of claim 2, comprising: a suction device that sucks outside air flowing from the first ventilation path and the second ventilation path into the connection path. The etching apparatus according to any one of claims 1 to 3, wherein the first ventilation path is viewed from the substrate carrying inlet to block the spray Provided in front of the mouth, the second ventilation path is provided from the substrate carrying port and is closed to seal the front side of the nozzle. An etching method for preventing the flow from the substrate transfer port and the substrate transfer port into the outside of the etching groove from the substrate transfer port having the substrate transfer port and the substrate transfer port toward the substrate transfer port Air flows into a gap between one surface of the substrate and the nozzle, and the reaction gas is blown from the nozzle to one surface of the substrate; and external air that flows into the etching chamber from the substrate inlet toward the gap is provided on the substrate. The first vent opening between the inlet and the nozzle flows into the first air passage, and the outside air that has flowed into the etching tank from the substrate carrying inlet is prevented from flowing into the gap, and flows into the gap from the substrate carrying port. The outside air in the etching tank flows into the second air passage from the second air vent provided between the substrate carrying port and the nozzle, and the outside air flowing into the etching tank from the substrate carrying port is prevented from flowing into the gap; the nozzle Containing gas pumping the above reaction gas mouth. The etching method of claim 5, wherein the suction flows into the outside air connecting the connection path of the first ventilation path and the second ventilation path. A method of manufacturing a substrate comprising the step of etching a substrate by the etching method of claim 5 or 6.