JP2019071407A - Surface treatment method and apparatus - Google Patents

Abstract

To suppress processing unevenness in dry etching of a substrate to be processed containing a silicon-containing substance such as a glass substrate.SOLUTION: A substrate 9 to be processed is passed through a processing region 22a by transfer means 30. A process gas containing hydrogen fluoride is supplied to the processing region 22a. Local drying spaces are provided on an upstream side and a downstream side in a transport direction of the processing region 22a, a drying gas with an absolute humidity lower than the atmospheric gas outside the processing region is supplied to the local drying spaces.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method and apparatus for surface treatment of a substrate to be treated containing a silicon content, and more particularly to a surface treatment method and apparatus for dry etching a surface to be treated.

In a process of manufacturing a flat panel display or the like using glass as a substrate, the glass substrate is likely to be peeled off and charged, and an electric circuit or the like may be destroyed by discharge after charging. Patent Document 1 proposes that the back surface of the glass substrate be subjected to dry etching with plasma containing a hydrogen fluoride gas to have a constant surface roughness in order to prevent the peeling and charging.
In patent document 2, the dry etching of the glass substrate is performed in the process area | region of the atmospheric pressure open | released outside.

Patent No. 5679513 JP, 2013-77721, A

When the processing area is open to the outside, while the glass substrate can be easily carried in and out, the external atmosphere gas is likely to be caught in the processing area.
According to the findings of the inventors, when the humidity of the external atmosphere gas is high, the treatment unevenness such as the formation of a white turbid part on the surface to be treated is caused by being caught in the treatment area.
An object of the present invention is to suppress processing unevenness in dry etching of a substrate to be processed including a silicon-containing material such as a glass substrate, in view of the circumstances.

In order to solve the above-mentioned subject, the inventor conducted earnest research and consideration.
As a solution, for example, it is conceivable to replace the entire processing chamber to be subjected to the surface treatment with nitrogen or to dry it. However, the running cost is high and the economy is bad.
Therefore, when both ends in the transport direction of the processing area were locally dried, processing unevenness could be prevented even if the humidity of the processing chamber was high.
The present invention has been made based on the above considerations and findings, and is a surface treatment method for dry etching a surface to be treated of a substrate to be treated containing a silicon-containing material,
Transporting the target substrate in a transport direction so as to pass through the processing region;
Supplying a process gas containing a fluorine-based reaction component to the processing region;
Supplying a drying gas having an absolute humidity lower than that of the atmosphere gas outside the processing region to the local drying spaces respectively provided on the upstream side and the downstream side in the transport direction of the processing region;
It is characterized by having.
Examples of the silicon-containing substance include SiO ₂ , SiN, Si, SiC, and SiOC.
The fluorine-based reaction component is a compound capable of reacting with the silicon-containing substance, and examples thereof include HF, COF _{2 and the} like.

Preferably, the drying gas is supplied in a laminar flow.
The relative humidity at 25 ° C. to 30 ° C. of the dry gas is preferably 10% RH or less.

The apparatus according to the present invention is a surface treatment apparatus for dry etching a surface to be treated of a substrate containing a silicon-containing material,
A processing unit having a processing area;
Transport means for transporting the substrate to be processed in the transport direction so as to pass through the processing area;
A process gas supply means for supplying a process gas containing a fluorine-based reaction component to the processing region;
A definition unit which is provided on the upstream side and the downstream side of the transport direction of the processing unit so as to be continuous with the processing region;
Drying gas supply means for supplying a drying gas having an absolute humidity lower than the atmosphere gas outside the processing region to the local drying space;
It is characterized by having.
It is preferable that a low humidity box defining a part of the local drying space is disposed below the passage of the substrate to be processed, and the upper surface of the low humidity box is open.
It is preferable that the dry gas supply means includes a diffusion nozzle for diffusing the dry gas in the width direction orthogonal to the transport direction and spraying the dry gas into the local drying space.

The process gas is preferably generated by plasmatizing a source gas containing a fluorine-containing gas and water under near atmospheric pressure.
The pressure in the processing region is preferably near atmospheric pressure.
In the present specification, the vicinity of the atmospheric pressure means a range of 1.013 × 10 ^{4 to} 50.663 × 10 ⁴ Pa, and in consideration of facilitation of pressure adjustment and simplification of the device configuration, 1.333 × 10 ⁴ ~10.664 × ¹⁰ 4 Pa, and more preferably from ^{9.331 × 10 4 ~10.397 × 10 4} Pa.

In the processing unit, the processing regions are respectively provided at a plurality of positions separated in the transport direction,
It is preferable that the definition part of the said local drying space is each provided in the upstream and downstream of the said conveyance direction in each process area | region.
By this, the surface roughening degree of a to-be-processed surface can be raised. Alternatively, even if the substrate to be treated is difficult to be roughened, the surface can be surely roughened.

  According to the present invention, processing unevenness can be suppressed in dry etching of a substrate to be processed containing a silicon-containing substance such as a glass substrate.

FIG. 1 is a front view showing a schematic configuration of a surface treatment apparatus according to a first embodiment of the present invention. FIG. 2 is a plan view of a nozzle portion of the surface treatment apparatus, taken along line II-II of FIG. FIG. 3 is a plan view taken along line III-III of FIG. 1 partially showing the aeration tube of the surface treatment apparatus. FIG. 4 is a front view showing a schematic configuration of a surface treatment apparatus according to a second embodiment of the present invention. FIG. 5 is a front view showing a schematic configuration of a surface treatment apparatus according to a third embodiment of the present invention. FIG. 6 is a front view showing a schematic configuration of a surface treatment apparatus according to a fourth embodiment of the present invention. FIG. 7 is a photograph of the surface to be treated of a glass substrate showing the results of Comparative Example 1. FIG. 8 is an AFM (atomic force microscope) image of the white spot of Comparative Example 1. FIG. 9 is an AFM (atomic force microscope) image of the transparent portion of Comparative Example 1. FIG. 10 is a photograph of the treated surface of the glass substrate showing the results of Example 5.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First Embodiment
FIG. 1 shows a surface treatment apparatus 1 according to a first embodiment of the present invention. The to-be-processed substrate 9 is a glass substrate which should become semiconductor devices, such as a flat panel display, for example. The glass substrate 9 contains a silicon-containing substance such as SiO ₂ as a main component.

  The surface treatment apparatus 1 roughens the surface to be treated 9 a (the back surface or the lower surface) of the glass substrate 9 by dry etching while transporting the glass substrate 9 in the transport direction MD. As a result, on the surface 9a to be treated, fine irregularities of surface roughness Ra = angstrom order to nanoorder, preferably Ra = 0.3 nm to 1 nm are formed.

The surface treatment apparatus 1 includes a treatment chamber 2 (treatment chamber), a process gas supply unit 3, a dry etching unit 20, and a conveyance unit 30. The process gas supply unit 3 includes a process gas generation unit 10 (HF generation unit) and a source gas supply unit 12.
The process gas generation unit 10 is configured of an atmospheric pressure plasma generation unit including a pair of electrodes 11 and 11 facing each other. Although not shown, a solid dielectric such as alumina (Al ₂ O ₃ ) is provided on the facing surface of at least one electrode. One of the electrodes 11 is connected to the high frequency power supply 15, and the other is electrically grounded. A preferably pulsed high frequency voltage is applied between the electrodes 11 to generate glow discharge near the atmospheric pressure, and the interelectrode space 11c becomes a discharge space.

The source gas supply unit 12 is connected to the upstream end of the interelectrode space 11c (discharge space). The fluorine-containing source gas contains a fluorine-containing gas, water (H ₂ O), and a carrier gas.
As the fluorine-containing gas, PFC (perfluorocarbon) such as CF ₄ , C ₂ F ₄ , C ₂ F ₆ , C ₃ F ₈ or the like, HFC (hydrofluorocarbon) such as CHF ₃ , CH ₂ F ₂ , CH ₃ F or the like It includes SF ₆ , NF ₃ , XeF ₂ and other fluorine-containing compounds. Here, CF ₄ is used as the fluorine-containing gas.

  Carrier gases include rare gases such as helium, argon, neon, xenon, nitrogen, and other inert gases. The carrier gas has a function as a dilution gas for diluting the fluorine-containing gas, a function as a discharge generated gas in the discharge space 11 c, and the like, in addition to the function of transporting the fluorine-containing gas.

The fluorine-containing source gas is plasmatized (including excitation, activation, radicalization, ionization, etc.) in the discharge space 11c, whereby the fluorine-containing gas (CF ₄ ) is decomposed to generate fluorine as a fluorine-based reaction component. Hydrogen fluoride (HF) is produced. As a result, a process gas is generated from the fluorine-containing source gas. The reaction formula for producing hydrogen fluoride is, for example, the following formula.
CF ₄ + 2H ₂ O → 4HF + CO ₂ (Equation 1)
The fluorine-based reaction component in the process gas is not limited to hydrogen fluoride (HF), and may be COF ₂ or the like.

  A process gas supply passage 13 is connected to the downstream end of the interelectrode space 11c (discharge space). The process gas supply path 13 extends to the processing chamber 2.

The internal pressure of the processing chamber 2 is approximately atmospheric pressure.
The processing unit 20 is accommodated in the processing chamber 2 (processing chamber). The processing unit 20 includes a nozzle unit 21 and an opposing member 23.

  As shown in FIGS. 1 and 2, the nozzle portion 21 is in the shape of a container extending in a width direction TD (direction orthogonal to the sheet of FIG. 1) orthogonal to the transport direction MD. A blowout port 21a and a suction port 21b are formed on an upper surface 21f (a processing area defining surface) of the nozzle portion 21. The blower outlet 21a is in the form of a slit extending in the width direction TD (direction orthogonal to the sheet of FIG. 1). The dimension in the width direction TD of the blowout port 21a is the same as or slightly larger than the width dimension of the glass substrate 9 (the dimension in the direction orthogonal to the paper surface of FIG. 1). Although not shown, a rectifying unit is provided inside the nozzle unit 21. The rectifying unit includes a chamber, a slit, a perforated plate, and the like (see, for example, JP-A-2004-006586). The process gas from the process gas supply passage 13 is made uniform in the width direction TD (the direction orthogonal to the sheet of FIG. 1) of the nozzle portion 21 by passing through the straightening unit, and then blown upward from the outlet 21a. Ru.

  The suction port 21b extends in a slit shape in the width direction TD (the direction orthogonal to the paper surface of FIG. 1). The suction port 21 b is connected to a suction unit (not shown) such as a vacuum pump via the suction passage 14.

The blowout port 21a and the suction port 21b are spaced apart on both sides (left and right in FIG. 1) of the nozzle upper surface 21f in the transport direction MD. Preferably, the blowout port 21a is disposed near the end of the nozzle upper surface 21f on the downstream side of conveyance (left side in FIG. 1), and the inlet 21b is the end of the upstream side of transfer on the nozzle upper surface 21f (right side in FIG. 1) It is arranged near.
Contrary to the above-described arrangement, the air outlet 21a may be disposed upstream of the conveyance, and the inlet 21b may be disposed downstream of the conveyance. The blower outlet 21a may be disposed at the central portion of the nozzle upper surface 21f in the transport direction, and the pair of suction outlets 21b may be disposed on the transport upstream side and the transport downstream side across the blower outlet 21a.
A substrate heating unit 4 such as an infrared heater is provided on the upstream side of the nozzle 21 in the transport direction MD.

  The opposing member 23 is disposed apart above the nozzle portion 21. The opposing member 23 is formed in a horizontal plate shape, and extends in parallel with the nozzle portion 21 in the width direction TD (the direction orthogonal to the paper surface of FIG. 1). The lower surface 23 a (facing surface) of the facing member 23 faces the top surface 21 f of the nozzle portion 21 in the vertical direction (facing direction). A flat space 22 is formed between the facing surfaces 23a and 21f. The flat space 22 extends in the width direction TD (the direction orthogonal to the plane of FIG. 1). As shown in FIG. 2, both ends of the flat space 22 in the width direction TD are closed by a pair of end walls 27.

The portion from the blowout port 21a to the suction port 21b in the flat space 22 is a processing area 22a. Both ends of the flat space 22 and thus in the transport direction MD of the processing region 22a are open and connected to the external atmosphere. Two directions orthogonal to the transport direction MD in the processing area 22a are closed by the upper and lower surfaces 23a and 21f and the pair of end walls 27. That is, the processing area 22a is closed except for both sides in the transport direction MD.
The internal pressure of the flat space 22 and thus of the processing region 22a is near the atmospheric pressure.

  The nozzle unit 21 doubles as one component of the processing unit 20 that defines the processing region 22 a and one component of the process gas supply unit 3 that supplies the process gas to the processing region 22 a.

  The transport means 30 is constituted by, for example, a roller conveyor, supports the glass substrate 9 horizontally, and takes the glass substrate 9 in and out of the loading / unloading port 2a of the processing chamber 2 along the transport direction MD, Pass through area 22a. The to-be-processed surface 9a of the glass substrate 9 at the time of conveyance is turned downward. The distance d from the nozzle upper surface 21 f to the surface 9 a (lower surface) of the glass substrate 9 being transported is, for example, about d = 1 mm to 5 mm.

In addition, as shown in FIGS. 1 and 2, the drive rollers 34 on both sides of the transport unit 30 in the immediate vicinity of the nozzle portion 21 have a cylindrical shape (round shape) with an axial length substantially the same as the width dimension of the nozzle portion 21. There is. Annular members 34 c made of a soft material such as an O-ring are provided on the outer peripheral portion of the drive roller 34 at intervals.
Further, the transport means 30 includes the free roller 35 of the nozzle upper surface 21 f. An annular body 35 c made of a soft material such as an O-ring is provided on the outer periphery of the free roller 35.
The annular bodies 34 c and 35 c are in contact with the glass substrate 9.
A shielding wall 36 is provided between the free rollers 35 adjacent in the width direction TD and further outside the free rollers 35 in the width direction.

The surface treatment apparatus 1 further includes a local drying unit 40. The local drying means 40 includes a pair of low humidity boxes 41 and a drying gas supply means 50.
As shown in FIG. 1, the pair of low humidity boxes 41 are respectively provided on the upstream side and the downstream side in the transport direction MD across the nozzle portion 21 and thus the processing region 22 a. Also, the low humidity box 41 is disposed below the passage of the glass substrate 9.

  As shown in FIG. 2, the low humidity box 41 extends in the width direction TD by the same length as the nozzle portion 21 in parallel with the nozzle portion 21. As shown in FIG. 1, the upper surface portion of the low humidity box 41 is open. Both end portions 23 e of the opposing member 23 in the transport direction project beyond the nozzle portion 21 and cover the low humidity box 41.

As shown in FIG. 1, the interior 42a of the low humidity box 41 and the space 42b between the upper end of the low humidity box 41 and the end 23e of the opposing member form a local drying space 42. The low humidity box 41 and the opposing member end 23 e constitute a defining portion 43 that defines the local drying space 42.
The local drying space 42 is provided on the upstream side and the downstream side of the transport direction MD of the processing region 22a. The drying space portion 42b of each local drying space 42 is continuous with the processing region 22a. The flat space 22 is configured by the processing area 22a and the drying space portion 42b on both sides thereof.

  As shown in FIG. 1 and FIG. 2, the drive roller 34 is accommodated in the low humidity box 41. An upper end portion of the drive roller 34 is slightly protruded from an upper end opening of the low humidity box 41.

As shown in FIG. 1, the dry gas supply means 50 includes a dry gas source 51, a dry gas supply passage 52, and an air diffuser 53 (dry gas blowing portion). Dry air is used as the dry gas of the dry gas source 51. The dry air has an absolute humidity lower than that of the atmosphere gas outside the processing area 22a. That is, the absolute humidity of the dry air is lower than the absolute humidity of the atmosphere gas at least near the inlet / outlet 2a outside the processing chamber 2, and furthermore, the absolute gas of the atmosphere gas in the space 2b outside the flat space 22 in the treatment chamber 2 Lower than humidity.
Preferably, the absolute humidity of the dry air is less than or equal to 10 g / m ³ . The relative humidity at 25 ° C. to 30 ° C. of the drying gas is preferably 10% RH or less.

  As shown in FIG. 1, drying gas supply paths 52 extend from the drying gas source 51 to the low humidity boxes 41. At the inside 42 a of the low humidity box 41, a diffuser tube 53 (diffusion nozzle) is provided. The tip of the dry gas supply passage 52 is connected to the air diffuser 53.

As shown in FIG. 2 and FIG. 3, the aeration pipe 53 is a pipe for the purpose of the diffusion effect of gas, has a large number of ejection holes 53 a, and extends over substantially the entire width of the low humidity box 41. The diameter of the ejection holes 53a is, for example, 10 μm or more on average, and the ejection porosity at about 500 μm is 70%.
The air diffusion tube 53 is disposed immediately below the drive roller 34 in the low-humidity box 41, but may be offset from the drive roller 34.
The gas diffusion method is not limited to the aeration tube 53.

The glass substrate 9 is dry etched (surface roughened) by the surface treatment apparatus 1 as follows.
By plasmatizing the fluorine-containing source gas in the process gas generation unit 10, a process gas containing hydrogen fluoride (HF) is generated. The process gas is sent to the etching processing unit 20 through the process gas supply path 13 and supplied from the blowout port 21a to the processing region 22a (process gas supply step).
The process gas in the processing region 22a flows from the blowout port 21a toward the suction port 21b.

Furthermore, dry gas is introduced from the dry gas source 51 to the air diffusion pipe 53 through the dry gas supply passage 52. The dry gas is spouted from the respective ejection holes 53a while diffusing in the aeration tube 53 in the width direction TD. By this, the dry gas is supplied to the inside 42 a of the low humidity box 41 (dry gas supply step). Furthermore, the drying gas is diffused upward from the opening at the upper end of the low humidity box 41 to fill the entire area of the local drying space 42. The flow rate of the drying gas is as small as possible so that the flow of the drying gas in the local drying space 42 is laminar.
It is possible to prevent or suppress that the drying gas of the local drying space 42 becomes a gas curtain and the outside atmosphere gas enters into the processing region 22a. Therefore, even if the humidity of the external atmosphere gas is high, the inside of the processing region 22a can be maintained at an appropriate moisture content.

  In parallel, the glass substrate 9 is transported by the transport means 30 along the transport direction (transport step). The glass substrate 9 is heated by the substrate heating unit 4 and then carried into the processing region 22a through the local drying space 42 on the upstream side of conveyance (right side in FIG. 1).

In the processing area 22 a, the process gas contacts the surface 9 a to be processed of the glass substrate 9. As a result, the hydrogen fluoride and the water vapor are condensed on the surface 9a to be treated to form an aggregation layer of hydrofluoric acid water. An etching reaction occurs between the aggregation layer of hydrofluoric acid water and the silicon content of the glass substrate 9. The reaction formula is, for example, the following formula.
SiO ₂ + 4HF + H ₂ O → SiF ₄ + 3H ₂ O (equation 2)
As a result, it is possible to form minute irregularities of about surface roughness Ra = angstrom order to nanoorder, preferably about 0.3 nm to 1 nm, on the surface 9a to be treated.

As described above, even if the humidity of the external atmosphere gas is high, the local drying unit 40 can maintain the inside of the processing region 22a with an appropriate amount of water, so that the thickness of the aggregation layer can be prevented from being excessive. Therefore, the etching reaction can be favorably performed. As a result, it is possible to prevent the occurrence of processing unevenness such as a clouded portion on the surface 9a to be treated.
By making the flow of the drying gas into a laminar flow, the influence of the drying gas on the flow of the process gas can be sufficiently reduced, and the surface of the glass substrate 9 can be surely roughened and the processing unevenness such as white turbidity can be surely made. Can be prevented.

Further, the glass substrate 9 is discharged from the processing region 22a to the outside of the processing unit 20 through the local drying space 42 on the conveyance downstream side (left side in FIG. 1).
By providing the local drying spaces 42 on both sides in the transport direction MD of the processing area 22a, it is possible to reliably prevent the processing unevenness such as the white turbid part from being formed on any of the front end side and the rear end side of the glass substrate 9 .
It is sufficient to locally dry only the side of the processing region 22a, and it is not necessary to dry the entire processing chamber (processing chamber), so that the increase in running cost can be suppressed, and economic efficiency can be ensured.

Next, another embodiment of the present invention will be described. The same reference numerals are assigned to the drawings for the same configurations as those described in the following embodiments.
Second Embodiment
FIG. 4 shows a second embodiment of the present invention. In the surface treatment apparatus 1B of the second embodiment, the surface roughening degree of the substrate to be treated 9 is made higher than that of the first embodiment (FIG. 1), or the substrate to be treated 9 which is harder to etch than the first embodiment is roughened. It is suitable for processing.

  Specifically, in the processing unit 20 of the surface treatment apparatus 1B, two (multiple) nozzle portions 21 are provided. The nozzles 21 are arranged in a line along the transport direction MD. The basic structure of each nozzle portion 21 is the same as that of the first embodiment, and the air outlet 21a and the air inlet 21b are separated from each other in the transport direction MD and are opened at the nozzle upper surface 21f (processing area defining surface).

A flat opposing member 23 is disposed above the nozzle portion 21. The opposing member 23 straddles the two nozzle portions 21. A processing region 22 a is defined between the portion from the outlet 21 a to the inlet 21 b of each nozzle portion 21 and the facing member 23.
In other words, in the processing unit 20 of the surface treatment apparatus 1B, treatment areas 22a are provided at two places (a plurality of positions) separated in the transport direction MD.

The local drying means 40 of the surface treatment apparatus 1B includes twice the number of the nozzle parts 21, that is, four low humidity boxes 41. Low humidity boxes 41 are provided on both sides (left and right in FIG. 4) of the nozzle portions 21 in the transport direction MD. Two low humidity boxes 41 are disposed between the two nozzle portions 21.
A diffuser 53 (drying gas blowing portion) of the drying gas supply means 50 is provided between the drive roller 34 and the bottom plate of the low humidity box 41 in each low humidity box 41. A drying gas supply path 52 branches from the drying gas source 51 and is connected to the air diffusion tubes 53 of the low humidity boxes 41.
A dry gas such as dry air from the dry gas source 51 is blown out from each aeration pipe 53 through the dry gas supply passage 52 so that a low humidity is established between each low humidity box 41 and the opposing member 23 above it. A local dry space 42 is formed.

The low humidity box 41 and the opposing member 23 constitute a defining portion 43 of the local drying space 42. That is, the defining portion 43 of the local drying space 42 is provided on the upstream side (left side in FIG. 4) and the downstream side (right side in FIG. 4) of the transport direction MD of each processing area 22a.
The absolute humidity of each local drying space 42 is lower than that of the atmosphere gas outside each processing area 22a. That is, the absolute humidity of each local drying space 42 is lower than the absolute humidity of the atmosphere gas at least near the inlet / outlet 2a outside the processing chamber 2, and further, the atmosphere of the space 2b outside the flat space 22 in the processing chamber 2 Lower than the absolute humidity of the gas.
The processing chamber 2 surrounds the whole of the two nozzle portions 21, the four low humidity boxes 41, and the opposing member 23. The internal pressure of the processing chamber 2 is approximately atmospheric pressure.

Furthermore, in the surface treatment apparatus 1B, an individual process gas supply unit 3B is provided for each nozzle unit 21. Each process gas supply unit 3B includes a source gas supply unit 12 and a process gas generation unit 10. The source gas supply unit 12 includes a gas box 12a. Each gas component (for example, CF ₄ , Ar, H ₂ O) of the fluorine-containing source gas and N ₂ gas for purge are introduced into the gas box 12 a.

The process gas generation unit 10 is connected to the outlet side (downstream side) of the gas box 12a. The process gas generation unit 10 is configured by an atmospheric pressure plasma generation unit (plasma unit) including at least a pair of electrodes (not shown) as in the first embodiment (FIG. 1). Between the pair of electrodes, a glow discharge near atmospheric pressure is generated, and the fluorine-containing source gas (CF ₄ + Ar + H ₂ O) is supplied to be plasmatized, thereby including hydrogen fluoride (HF). Gas is produced.

A process gas supply path 13 extends from each process gas generation unit 10. The process gas supply passage 13 is connected to the outlet 21 a of the corresponding nozzle unit 21.
Although not shown in detail, the process gas supply passage 13 between the process gas generation unit 10 and the nozzle unit 21 preferably has a double-pipe structure of an inner pipe and an outer pipe. A process gas is passed through the inner pipe in the double pipe, and the space between the outer pipe and the inner pipe is an air layer for heat retention. More preferably, the process gas supply passage 13 is warmed or kept warm by a heater such as a ribbon heater.

  According to the surface treatment apparatus 1B, the process gas flows from the blowout port 21a toward the suction port 21b in each processing area 22a. And by the conveyance means 30, the to-be-processed substrate 9 is sequentially passed through two (plural) process area | regions 22a along conveyance direction MD. Therefore, the processing surface 9a of the processing target substrate 9 is roughened (etched) in the processing region 22a on the upstream side (left side in FIG. 4) in the transport direction MD, and subsequently on the downstream side in FIG. The roughening process is further performed in the processing area 22a on the right side). By this, the surface roughness degree of the to-be-processed surface 9a can be raised. Alternatively, even for the processing target substrate 9 which is hard to be roughened, the surface can be surely roughened.

Furthermore, since the local drying spaces 42 are formed on both sides of the transport direction MD of each processing area 22a, the inside of each processing area 22a can be maintained at an appropriate moisture content (humidity). Therefore, the etching reaction in each processing region 22a can be favorably performed.
The processing substrate 9 passes through the local drying space 42 immediately before being introduced into each processing region 22a and immediately after passing through each processing region 22a. As a result, it is ensured that processing unevenness such as a white turbid portion can be made on both the front end side (right side in FIG. 4) and the rear end side (left side in FIG. 4) of the transport direction MD of the substrate 9 to be processed. It can prevent.

Third Embodiment
As shown in FIG. 5, the third embodiment relates to a modification of the second embodiment (FIG. 4). In the surface treatment apparatus 1C of the third embodiment, one low humidity box 41C is disposed between the two nozzle portions 21. The one low humidity box 41C serves both as the downstream low humidity box of the upstream side (left side in FIG. 5) of the nozzle portion 21 and the upstream low humidity box of the downstream side (right side in FIG. 5) of the nozzle portion 21. The local drying means 40 includes three low humidity boxes 41, 41C, 41.

Fourth Embodiment
As shown in FIG. 6, 4th Embodiment concerns on the modification of 2nd Embodiment (FIG. 4). In surface treatment apparatus 1D of a 4th embodiment, common (single) source gas supply part 12 and process gas generation part 10 are used to two (plural) nozzle parts 21. The process gas supply passage 13 is branched into two (multiple) branch passages 13 b. Each branch passage 13 b is connected to the outlet 21 a of the corresponding nozzle portion 21.
Thereby, the process gas from one process gas generation unit 10 can be divided and supplied to the two (plurality) nozzle units 21.

Further, for example, by providing an on-off valve (not shown) in each branch path 13b, the nozzle portion 21 for supplying the process gas can be selected according to the transport position of the substrate 9 to be processed.
Specifically, when the substrate 9 to be processed passes through the processing region 22a on the upstream side (left side in FIG. 6) in the transport direction MD, the process gas is supplied only to the nozzle portion 21 on the upstream side. The process gas to the nozzle unit 21 on the right side in FIG. 6 may be stopped, and when the substrate 9 to be processed passes the processing region 22 a on the downstream side (right side in FIG. 6), the nozzle unit 21 on the downstream side Alternatively, the process gas may be supplied to the upstream side (left side in FIG. 6) of the process gas to the nozzle portion 21.

The present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the invention.
For example, the hydrogen fluoride of the process gas is not limited to that generated by plasma discharge. The HF generation means is not limited to atmospheric pressure plasma, and may be corona discharge. A gas obtained by vaporizing the hydrogen fluoride aqueous solution may be used as the process gas. Alternatively, dry etching may be performed by bubbling a hydrogen fluoride aqueous solution.
The dry gas is not limited to dry air, and may be dry nitrogen or other dry inert gas.
In the surface treatment apparatuses 1B, 1C, and 1D of the second to fourth embodiments (FIGS. 4 to 6), the number of the nozzle portions 21 and the processing areas 22a is not limited to two, and may be three or more.
In the third embodiment (FIG. 5), as in the fourth embodiment (FIG. 6), the common (single) source gas supply unit 12 and the process gas generation unit 10 are used for the plurality of nozzle units 21. It may be

Examples will be described. The present invention is not limited to the following examples.
A surface treatment apparatus having substantially the same configuration as the apparatus 1 shown in FIG. 1 was used.
The glass substrate 9 was passed through the processing region 22a as a substrate to be processed.
The width of the glass substrate 9 (dimension in the direction perpendicular to the paper surface of FIG. 1) was 370 mm.
The length of the glass substrate 9 in the transport direction (left and right direction in FIG. 1) was 470 mm.
The transfer speed of the glass substrate 9 was 2.5 m / min.
The heating temperature of the glass substrate 9 by the heating unit 4 was 45 ° C.

A dry gas consisting of dry air was supplied to the local dry spaces 42 on both sides.
The temperature of the drying gas was 25 ° C., and the relative humidity was 8% RH.
The supply flow rate of drying gas to each local drying space 42 was 25 slm.
The temperature of the external atmosphere (air) was 30 ° C., and the relative humidity was 30% RH. The external atmosphere was temperature controlled and controlled by a precision air conditioner.

In the process gas generation unit 10, a fluorine-containing source gas containing CF ₄ , Ar and H ₂ O is plasmatized to generate a process gas.
The flow rate of CF ₄ of the fluorine-containing source gas was 0.8 slm, and the flow rate of Ar was 11.2 slm.
The flow rate of the process gas was 12 slm.
The dew point of the process gas was 30.degree.
The process gas is supplied to the processing region 22 a to contact the processing surface 9 a of the glass substrate 9.

  The processing surface 9a of the glass substrate 9 after the processing had no processing unevenness such as white turbidity, and a good etching process could be performed. The surface roughness was 0.82 nm.

Comparative Example 1
As a comparative example, the dry gas supply was stopped and the etching process of the glass substrate 9 was performed. That is, the supply flow rate of the drying gas to each local drying space 42 was set to 0 L / min. The other conditions were the same as in Example 1.
As shown in the photograph of FIG. 7, on the treated surface 9 a of the glass substrate 9 after the treatment in Comparative Example 1, treatment unevenness such as white turbidity was formed. FIG. 8 is an AFM image of the white spot of Comparative Example 1. FIG. 9 is an AFM image of the transparent portion of Comparative Example 1.
If the distribution of roughness is not uniform in the glass surface, the processing unevenness can be recognized due to the difference in contrast.
Even if Ra is almost the same value, if it is in the same plane, the difference in the etching shape causes a difference in contrast, which appears as uneven processing (FIG. 8).
If the roughness is uniformly expressed (pin-like shape), the processing unevenness can not be recognized even with high Ra (FIG. 9).

In Example 2, the temperature of the external atmosphere was 30 ° C., and the relative humidity was 50% RH.
The other conditions were the same as in Example 1.
Also in Example 2, the processing surface 9a of the glass substrate 9 after the processing had no processing unevenness such as white turbidity, and a good etching process could be performed.

In Example 3, the temperature of the external atmosphere was 30 ° C., and the relative humidity was 60% RH.
The other conditions were the same as in Example 1.
Also in Example 3, the processing surface 9a of the glass substrate 9 after the processing had no processing unevenness such as white turbidity, and a good etching process could be performed.

In Example 4, dry air was used as the dry gas, and the local dry space 42 had a temperature of 28.9 ° C., a relative humidity of 8% RH, and an absolute humidity (moisture content) of 2.3 g / m ³ .
The atmosphere gas of the processing chamber 2, that is, the atmosphere gas of the outside 2b of the processing unit 20 was a temperature of 30 ° C., a relative humidity of 30% RH, and an absolute humidity (water content) of 9.1 g / m ³ .
The other processing conditions were the same as in Example 1.
The processing surface 9a of the glass substrate 9 after the processing had no processing unevenness such as white turbidity, and a good etching process could be performed. The surface roughness was 0.82 nm.

In Example 5, dry nitrogen (N ₂ ) was used as the drying gas. The local drying space 42 had a temperature of 28.4 ° C., a relative humidity of 6% RH, and an absolute humidity (water content) of 1.7 g / m ³ .
The atmosphere gas of the processing chamber 2, that is, the atmosphere gas of the outside 2b of the processing unit 20 was a temperature of 30 ° C., a relative humidity of 30% RH, and an absolute humidity (water content) of 9.1 g / m ³ .
The other processing conditions were the same as in Example 1 and Example 4.
FIG. 10 is a photograph taken by irradiating light to the edge of the glass substrate 9 after the processing of the fifth embodiment. As shown in the figure, the processed surface 9a of the glass substrate 9 after the processing was free from uneven processing such as white turbidity, and a good etching process could be performed. The surface roughness was 0.79 nm. The surface roughness equivalent to dry air (Example 4) was obtained using dry nitrogen.

  The invention is applicable, for example, to the manufacture of flat panel displays.

MD transport direction
TD Width direction 1, 1B to 1D Surface treatment device 2 Processing chamber (treatment chamber)
2b Outer space (outside of processing area)
3, 3B Process gas supply means 9 Substrate 9a to be processed 10 Process gas generation unit 12 Raw material gas supply unit 12a Gas box 13 Process gas supply passage 13b Branching passage 13v Opening and closing valve 20 Processing unit 21 Nozzle unit 21a Suction port 21b Suction Mouth 22a treatment area 30 transport means 34 drive roller 35 free roller 40 local drying means 41, 41C low humidity box 42 local drying space 43 defining unit 50 drying gas supply means
52 Drying gas supply passage 53 Aeration tube (drying gas outlet)
53a vent hole

Claims (7)

A surface treatment method for dry etching a treated surface of a substrate to be treated containing a silicon-containing substance, comprising:
Transporting the target substrate in a transport direction so as to pass through the processing region;
Supplying a process gas containing hydrogen fluoride to the processing region;
Supplying a drying gas having an absolute humidity lower than that of the atmosphere gas outside the processing region to the local drying spaces respectively provided on the upstream side and the downstream side in the transport direction of the processing region;
A surface treatment method comprising:   The surface treatment method according to claim 1, wherein the drying gas is supplied in a laminar flow.   The surface treatment method according to claim 1, wherein a relative humidity at 25 ° C. to 30 ° C. of the drying gas is 10% RH or less. A surface treatment apparatus for dry etching a surface to be treated of a substrate to be treated containing a silicon-containing substance, comprising:
A processing unit having a processing area;
Transport means for transporting the substrate to be processed in the transport direction so as to pass through the processing area;
A process gas supply means for supplying a process gas containing hydrogen fluoride to the processing region;
A definition unit which is provided on the upstream side and the downstream side of the transport direction of the processing unit so as to be continuous with the processing region;
Drying gas supply means for supplying a drying gas having an absolute humidity lower than the atmosphere gas outside the processing region to the local drying space;
A surface treatment apparatus comprising:   The surface according to claim 4, wherein a low humidity box defining a part of the local drying space is disposed below the passage of the substrate to be treated, and the upper surface of the low humidity box is open. Processing unit.   The surface treatment apparatus according to claim 4 or 5, wherein the dry gas supply means includes a diffusion nozzle for diffusing the dry gas in the width direction orthogonal to the transport direction and spraying the dry gas into the local dry space. In the processing unit, the processing regions are respectively provided at a plurality of positions separated in the transport direction,
The surface treatment apparatus according to any one of claims 4 to 6, wherein a defining portion of the local drying space is provided on the upstream side and the downstream side of the transport direction in each processing region.