WO2012043384A1

WO2012043384A1 - Apparatus for etching silicon-containing material

Info

Publication number: WO2012043384A1
Application number: PCT/JP2011/071639
Authority: WO
Inventors: 崇志福田; 真弓　聡; 俊介功刀
Original assignee: 積水化学工業株式会社
Priority date: 2010-09-29
Filing date: 2011-09-22
Publication date: 2012-04-05
Also published as: JP2013251290A; TW201220391A

Abstract

The purpose of the present invention is to improve uniformity of etching of a silicon-containing material. A substrate (9) to be processed, said substrate being coated with a silicon-containing material (9a), is supported on a virtual plane (PL), and the substrate is relatively moved in the transfer direction (x) with respect to a nozzle (30). A processing gas containing a fluorine-based reactive component is brought into contact with a substrate to be processed (9) by blowing out the processing gas from a blow out port (31) of the nozzle (30). The nozzle (30) extends in the width direction (y) that orthogonally intersects the transfer direction (x), and a cross-section that orthogonally intersects the width direction (y) is tapered toward the virtual plane (PL). The blow out port (31) is opened in the tip of the nozzle (30). A reaction field (1a) is defined between the tip of the nozzle (30) and the virtual plane (PL), and a diffusion space (1e) is defined between the tilted side surface (34) of the nozzle (30) and the virtual plane (PL).

Description

Silicon-containing material etching equipment

This invention relates to an apparatus for etching silicon-containing materials such as amorphous silicon.

For example, an etching apparatus that etches a surface film of an object to be processed by spraying a processing gas from the nozzle onto the object to be processed while moving the object to be processed such as a glass substrate for a flat panel display relative to the nozzle in the transport direction. Is known (see Patent Documents 1 and 2, etc.). In general, the tip surface of this type of nozzle (the surface facing the object to be processed) is a flat surface having a certain area. The processing gas stays for a while between the tip surface of the nozzle and the object to be processed, so that the processing reaction is sufficiently caused. In the nozzles of Patent Documents 1 and 2, for example, three (a plurality of) blowing holes are formed side by side in the conveyance direction of the workpiece. A pair of suction holes are formed on both sides in the transport direction across each blowing hole. The opening at the lower end of each suction hole and the opening at the lower end of the blowing hole are separated from each other in the transport direction.

JP 2009-129996 A JP 2009-129998 A

As shown in FIG. 14, the inventor performed an amorphous silicon etching process using the nozzle 5 having substantially the same structure as that described in Patent Documents 1 and 2. The dimension along the conveyance direction (left-right direction in FIG. 14) of the tip surface 5e of the nozzle 5 is 300 mm, and the dimension in the width direction (direction perpendicular to the paper surface in FIG. 14) perpendicular to the conveyance direction of the nozzle tip surface 5e is 640 mm. Met. The pitch of the three blowing

holes

5a, 5a, 5a was 100 mm, and the interval between each blowing hole 5a and the suction hole 5b was 25 mm. Each blowout hole 5a and suction hole 5b were slit-shaped extending in the width direction. A processing gas containing HF and O ₃ was blown out from the three blowing

holes

5a, 5a, and 5a while the glass substrate 9 coated with amorphous silicon was carried in the carrying direction by the roller conveyor 6. As a result, a plurality of streaky processing irregularities extending in the width direction were formed on the surface of the glass substrate 9 at a pitch of 100 mm in the transport direction.

Therefore, as shown in FIG. 15, an amorphous silicon etching process was similarly performed using a nozzle 5X having only one blowing hole 5a. The dimension along the conveying direction (left-right direction in FIG. 15) of the tip surface 5e of the nozzle 5X is 22 mm, and one blowing hole 5a is provided at the exact center. The dimensions of the nozzle 5X in the width direction (direction perpendicular to the paper surface of FIG. 15) and the point that the blowout holes 5a are slit-shaped extending in the width direction are the same as those of the nozzle 5 (FIG. 15). As a result, the above-mentioned streaky process unevenness was not formed. On the other hand, the amount of etching processing at the front end portion and the rear end portion in the traveling direction of the substrate 9 was lower than that at the center portion.

Further, as shown in FIG. 16, a flat rectifying plate 7 facing the nozzle 5X is disposed slightly below the height at which the substrate 9 is conveyed, and an amorphous silicon etching process is performed. The dimension along the conveying direction of the rectifying plate 7 (left and right direction in FIG. 16) was 63 mm, and the dimension of the rectifying plate 7 in the width direction (direction perpendicular to the paper surface of FIG. 16) was the same as that of the nozzle 5X. Then, the difference in etching processing amount between the front and rear end portions and the central portion in the traveling direction of the substrate 9 is reduced, but the etching processing amount is large at the front end portion in the traveling direction, and the etching processing amount is large at the rear end portion in the traveling direction. It has become smaller.

The blowout flow velocity from the nozzle 5X was 0.4 m / s, and the Reynolds number was 0.07. Therefore, it is considered that the processing gas newly blown out does not have a momentum enough to push out the processed gas blown out first. Therefore, the processed gas stays between the nozzle front end surface 5e and the substrate 9 to reduce the reaction component concentration in the newly blown processing gas. As a result, the etching processing amount on the surface of the substrate is reduced. This is thought to have caused variations.

The present invention has been made on the basis of the above knowledge, and an object of the present invention is to improve the uniformity of the etching process when etching a silicon-containing material such as amorphous silicon near atmospheric pressure.

In order to achieve the above object, the present invention provides an etching apparatus for etching a silicon-containing material by bringing a processing gas containing a fluorine-based reaction component into contact with a substrate to be processed containing the silicon-containing material under atmospheric pressure. In
A support unit for supporting the substrate to be processed on a virtual plane;
A nozzle having a blowing hole for blowing out the processing gas and extending in the width direction of the virtual plane;
Transport means for moving the substrate to be processed relative to the nozzle in the transport direction along the virtual plane and perpendicular to the width direction;
The nozzles are extremely thin (the dimension in the transport direction is extremely small) and the tip edge extending in the width direction and a pair on both sides of the transport direction and approach each other as they approach the tip edge A cross section perpendicular to the width direction is pointed toward the virtual plane, the blowing holes are distributed in the width direction and open to the tip edge, and the tip edge and the virtual side A reaction field is defined between the pair of inclined side surfaces and the virtual plane, and diffusion spreads in a direction perpendicular to the virtual plane as the distance from the reaction field in the transport direction increases. It is characterized by a defined space.

According to the above characteristic configuration, the uniformity of the etching treatment of the silicon-containing material can be improved. According to the inventor's experiment, even when a plurality of nozzles are arranged in the transport direction, it was possible to prevent the formation of streak-like processing unevenness on the surface of the substrate to be processed (see Example 1 described later). The reason is considered as follows. That is, the processing gas is blown out from the blowing hole and comes into contact with the substrate to be processed in the reaction field. This contact causes an etching reaction of the silicon-containing material. Diffusion spaces are connected to both sides of the reaction field in the transport direction. The process gas diffuses into the diffusion space immediately after the contact in the reaction field. Since the diffusion space is expanded as the distance from the reaction field increases, diffusion resistance hardly occurs. Therefore, even if the blowing speed of the processing gas is small, the processing gas blown earlier can be surely pushed out from the reaction field by the newly blown flow. Therefore, fresh process gas always contacts the substrate to be processed in the reaction field. Therefore, it can prevent that the density | concentration of the reaction component in the process gas in a reaction field falls. Most of the etching reactions occur locally only within a narrow reaction field. The local etching rate in the reaction field is the same even when the front end of the substrate to be processed is located in the reaction field or when the central part of the substrate is located in the reaction field. Even when the rear end portion of the substrate in the traveling direction is located in the reaction field, it is almost uniform. In the diffusion space, the processing gas is sufficiently diffused and the reaction component concentration is greatly reduced, so that the etching reaction hardly occurs. Therefore, the entire substrate to be processed can be etched almost uniformly. As a result, it is considered that even when a plurality of nozzles are arranged in the transport direction, it is possible to prevent or suppress the formation of streak-like processing unevenness extending in the width direction on the surface of the substrate to be processed.

The average flow velocity of the processing gas in the blowing holes is preferably 0.1 m / s to 1.0 m / s, more preferably 0.2 m / s to 0.6 m / s. By suppressing the blowing flow rate of the processing gas to a small value, it is possible to prevent the airflow in the processing tank from being disturbed. Even if the blowing flow rate is small, a sufficient etching rate can be secured. In addition, the effect of reducing the diffusion resistance described above and the effect of preventing the turbulence of the airflow in the treatment tank can be combined to sufficiently ensure the uniformity of the treatment. Here, the average blowing flow rate is obtained by dividing the blowing flow rate by the cross-sectional area of the blowing hole.

The nozzle may be formed with a suction hole connected to the gas suction means, and the suction hole may be opened at the tip edge so as to be in contact with the blowout hole.
During the etching process, the gas in the vicinity of the opening of the suction hole at the tip edge is locally sucked into the suction hole by the gas suction means in parallel with the blowing of the processing gas. For this reason, the processing gas is blown out from the blowing hole and comes into contact with the substrate to be processed, and is immediately sucked into the suction hole. Therefore, it is possible to more reliably prevent the treated gas from staying in the reaction field, and it is possible to more reliably prevent a decrease in the concentration of reaction components in the reaction field. Furthermore, the flow state such as the flow velocity and direction of the processing gas in the reaction field can be made even more reliable regardless of the position of the substrate to be processed in the traveling direction. Therefore, the uniformity of the etching process can be further improved.

It is preferable that a rectifying plate facing the nozzle across the virtual plane is provided along the virtual plane, and the rectifying plate extends from the pair of inclined side surfaces to both sides in the transport direction. As a result, even if the virtual plane is a virtual plane, the state of the flow in which the processing gas diffuses into the diffusion space can be kept substantially constant regardless of the traveling position of the substrate to be processed. As a result, the state of the processing gas flow in the reaction field can be reliably kept substantially constant regardless of the position of the substrate to be processed. Therefore, the uniformity of the etching process can be further improved.

The apparatus further includes a processing gas supply unit that supplies the processing gas to the nozzle, and the processing gas supply unit includes a plasma generation unit that includes a pair of electrodes that generate a discharge under atmospheric pressure between each other, and contains fluorine It is preferable that the fluorine-based reaction component is generated by introducing a raw material gas containing a component and a hydrogen-containing additive component into the space between the pair of electrodes and converting it into plasma.
As fluorine-containing components, PFC (perfluorocarbon) such as CF ₄ , C ₂ F ₄ , C ₂ F ₆ , C ₃ F ₈ , HFC (hydrofluorocarbon) such as CHF ₃ , CH ₂ F ₂ , CH ₃ F, etc. Other examples include SF ₆ , NF ₃ , XeF ₂ , and F ₂ . The hydrogen-containing additive component is preferably water (H ₂ O), and other examples include OH group-containing compounds such as alcohol and hydrogen peroxide.
In this specification, the term “near atmospheric pressure” means a range of 1.013 × 10 ⁴ to 50.663 × 10 ⁴ Pa, and considering the ease of pressure adjustment and the simplification of the apparatus configuration, 1.333 × 10 6. ⁴ to 10.664 × 10 ⁴ Pa is preferable, and 9.331 × 10 ⁴ to 10.9797 × 10 ⁴ Pa is more preferable.

According to the present invention, the uniformity of the etching treatment of the silicon-containing material can be improved.

1 is a side view of an etching apparatus according to a first embodiment of the present invention. FIG. 2 is a plan sectional view taken along line II-II in FIG. 1. It is a perspective view of the nozzle of the said etching apparatus. It is side surface sectional drawing which expands and shows a part of nozzle of the said etching apparatus. It is side surface sectional drawing which shows the modification of the nozzle of the said etching apparatus. It is side surface sectional drawing which shows the modification of the nozzle of the said etching apparatus. It is side surface sectional drawing which shows the modification of the nozzle of the said etching apparatus. It is side surface sectional drawing which shows the modification of the nozzle of the said etching apparatus. It is side surface sectional drawing which shows the modification of the nozzle of the said etching apparatus. It is side surface sectional drawing of the nozzle of the etching apparatus which concerns on 2nd Embodiment of this invention. FIG. 11 is a bottom view of the nozzle of the etching apparatus according to the second embodiment, taken along line XI-XI in FIG. 10. It is a side view of the etching apparatus which concerns on 3rd Embodiment of this invention. It is a side view of the etching apparatus which concerns on 4th Embodiment of this invention. It is side surface sectional drawing of the nozzle apparatus as a reference example in the process leading to this invention. It is side surface sectional drawing of the nozzle apparatus as a reference example in the process leading to this invention. It is side surface sectional drawing of the nozzle apparatus as a reference example in the process leading to this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 and 2 show an etching apparatus 1 according to a first embodiment of the present invention. The substrate 9 to be processed is composed of, for example, a glass substrate of a liquid crystal display panel and has a thin flat plate shape. The thickness t of the substrate 9 to be processed is, for example, about t = 0.4 mm to 1.1 mm. A surface of the substrate 9 to be processed (upper surface in FIG. 1) is coated with a silicon-containing material 9a (FIG. 4) to be etched. The silicon-containing material is made of, for example, amorphous silicon. In addition to amorphous silicon, the silicon-containing material may be single crystal silicon or polycrystalline silicon, and is not limited to silicon alone, but may be silicon nitride, silicon oxide, silicon carbide, or the like.

The etching apparatus 1 brings a processing gas into contact with the substrate 9 to be processed under atmospheric pressure and performs an etching process on the silicon-containing material. The processing gas contains a fluorine-based reaction component. Examples of the fluorine-based reaction component include HF, COF ₂ , OF ₂ , and O ₂ F ₂ . When the silicon-containing material is silicon such as amorphous silicon, the processing gas further contains an oxidizing reaction component. Examples of the oxidizing reaction component include O ₃ and O radicals.

As shown in FIG. 1, the etching apparatus 1 includes a processing tank 2, a processing gas supply unit 10, a roller conveyor 20, and a nozzle 30. The processing tank 2 accommodates the nozzle 30 and a part of the conveyor 20. The pressure in the processing tank 2 is near atmospheric pressure.

The processing gas supply unit 10 includes a plasma generation unit 11 for generating a fluorine-based reaction component and an oxidizing reaction component supply unit 16. The plasma generation unit 11 has a pair of electrodes 12 facing each other. A solid dielectric layer (not shown) is provided on the opposing surface of both or one of the electrodes 12. The power source 3 is connected to one electrode 12, and the other electrode 12 is electrically grounded. By supplying power from the power supply 3, for example, a pulsed high-frequency electric field is applied between the pair of electrodes 12. As a result, glow discharge is generated between the electrodes 12 near atmospheric pressure.

A fluorine raw material supply unit 14 is connected to a space 13 between the electrodes 12. An addition unit 15 is connected to a path connecting the fluorine raw material supply unit 14 and the interelectrode space 13. A raw material gas containing a fluorine-containing component is sent from the fluorine raw material supply unit 14, and a hydrogen-containing additive component from the addition unit 15 is added thereto. The added source gas is introduced into the interelectrode space 13. Thereby, in the inter-electrode space 13, the source gas is turned into plasma (including excitation, decomposition, radicalization, and ionization), and a fluorine-based reaction component such as HF is generated.

Examples of the fluorine-containing component used as a raw material for the fluorine-based reaction component include PFC (perfluorocarbon) such as CF ₄ , C ₂ F ₄ , C ₂ F ₆ , and C ₃ F ₈ , CHF ₃ , CH ₂ F ₂ , and CH ₃ F. HFC (hydrofluorocarbon) such as Furthermore, as the fluorine-containing _component, it may be used _{_{SF 6, NF 3, XeF 2}} , F 2 and the like. Here, for example, CF ₄ is used as the fluorine-containing component.

The fluorine raw material supply unit 14 dilutes the fluorine-containing component with the dilution component. The diluent components, Ar, He, Ne, other rare gases Kr, etc., include inert gas such as _{N 2.} In addition to the role of diluting the fluorine-containing component, the dilution component plays a role as a carrier gas and a gas for plasma generation. Here, for example, Ar is used as a dilution component.

The hydrogen-containing additive component is water vapor (H ₂ O). The addition part 15 is comprised with the vaporizer of water. Water is stored in the vaporizer 15 in a liquid state. Fluorine-based source gas (CF ₄ + Ar) from the supply unit 14 is introduced into the liquid in the vaporizer 15 and bubbled. Alternatively, the raw material gas may be introduced to the upper part of the liquid level in the vaporizer 15 and the saturated vapor in the upper part may be pushed out by the raw material gas. Thereby, water vapor is added to the source gas. By adjusting the temperature of the vaporizer 15, it is possible to adjust the vapor pressure of water and thus the amount of addition. Alternatively, a part of the raw material gas (CF ₄ + Ar) is introduced into the vaporizer 15, the remainder bypasses the vaporizer 15, and the flow rate ratio between the part and the remainder is adjusted to reduce the amount of water added. You may adjust. As an additive component, an OH group-containing compound, hydrogen peroxide, or the like may be used instead of water. Examples of the OH group-containing compound include alcohol.

The oxidizing reaction component supply unit 16 is configured by an ozonizer. The ozonizer 16 generates O ₃ as an oxidizing reaction component using O ₂ as a raw material. The oxidizing reaction component is not limited to O ₃ but may be O radical or NOx. If the silicon-containing film to be etched is silicon oxide or the like, the oxidizing reaction component supply unit 16 may be omitted.

Next, the roller conveyor 20 and the nozzle 30 will be described. The roller conveyor 20 has a function as a support unit that supports the substrate 9 to be processed and a function as a transport unit that transports the substrate 9 to be processed.

As is well known, the roller conveyor 20 has a shaft 21 and a roller 22. A plurality of shafts 21 are arranged at intervals in the x direction (conveying direction, left and right in FIG. 1). The axis of each shaft 21 is horizontally oriented in the y direction (width direction, the direction orthogonal to the plane of FIG. 1) perpendicular to the x direction. A plurality of rollers 22 are provided on each shaft 21 at intervals in the y direction. The substrate 9 to be processed is placed horizontally on the roller 22 in a flat state. The roller conveyor 20 supports the substrate 9 to be processed on a virtual horizontal plane PL that is the height of the upper end of the roller 22 and conveys the substrate 9 to be processed in the x direction along the virtual plane PL.

As shown in FIG. 1, a nozzle 30 is disposed above the roller conveyor 20 in the processing tank 2. The nozzle 30 is supported by the upper part in the processing tank 2 with the mount which is not shown in figure. As shown in FIGS. 2 and 3, the nozzle 30 extends long in the y direction (the width direction of the virtual plane). The length of the nozzle 30 in the y direction is sufficiently larger than the dimension of the nozzle 30 in the x direction, and is preferably larger than the length of the substrate 9 to be processed in the y direction. As shown in FIG. 1, the central axis CL of the cross section perpendicular to the extending direction of the nozzle 30 is perpendicular to the virtual plane PL and thus perpendicular to the substrate 9 to be processed.

A blowing hole 31 is formed inside the nozzle 30. As shown in FIG. 4, the blowing hole 31 extends vertically along the central axis CL. The width w in the x direction of the blowout hole 31 is preferably about w = 1 mm to 6 mm, and more preferably about w = 4 mm. As shown in FIG. 2, the blowout holes 31 are distributed over almost the entire length of the nozzle 30 in the longitudinal direction (y direction). Specifically, the blowout hole 31 extends long in the y direction and has a slit shape. The blowing hole 31 may be configured by a large number of small holes arranged in the y direction instead of the slit shape. The length (distribution width) in the y direction of the blowout holes 31 is slightly larger than the length in the y direction of the substrate 9 to be processed. In planar projection view, it is preferable that each end portion in the y direction of the blowing hole 31 slightly protrudes outward from the end portion on the same side in the y direction of the substrate 9 to be processed. The blowout hole 31 may be configured by a large number of small holes arranged in the y direction.

As shown in FIG. 1, the base end portion (upper end portion) of the blowing hole 31 is connected to the supply path 19 from the processing gas supply unit 10. Although illustration is omitted, a rectification unit is provided between the supply path 19 and the processing gas supply unit 10. The rectifying unit includes a chamber extending in the y direction, slits extending in the y direction, and a large number of small holes dispersed in the y direction. The processing gas is made uniform in the y direction by passing through the rectifying unit.

As shown in FIGS. 3 and 4, the cross section perpendicular to the y direction of the upper portion 32 of the nozzle 30 is rectangular. On the other hand, the cross section orthogonal to the y direction of the lower portion 33 of the nozzle 30 is tapered so as to point toward the virtual plane PL. The nozzle lower portion 33 has a pair of inclined side surfaces 34 and 34 on both sides in the x direction, and a tip edge 35 facing the virtual plane PL. The pair of inclined side surfaces 34, 34 are inclined surfaces that are inclined with respect to the central axis CL so as to approach each other toward the tip edge 35. At the tip (lower end) of the nozzle 30, the pair of inclined side surfaces 34 and 34 are sufficiently close to each other, and a nozzle tip edge 35 is formed between the lower ends of the inclined side surfaces 34 and 34. The nozzle tip edge 35 is extremely thin, that is, has a very small dimension in the x direction and extends long in a straight line in the y direction (the direction perpendicular to the plane of FIG. 1).

The tip (lower end) of the blowout hole 31 reaches the nozzle tip edge 35 and opens to form a blowout port. Nearly the entire nozzle tip edge 35 is a blowout port. The width of the tip edge of the nozzle 30 in the x direction is the same as the width of the blowout hole 31 in the x direction, and is about 4 mm, for example. At the tip (lower end) of the nozzle 30, the inclined side surface 34 and the inner surface of the blowout hole 31 on the same side of the center axis CL intersect each other at an acute angle to form a knife edge 35e. The knife edge 35e extends in the y direction (a direction perpendicular to the paper surface of FIG. 4).

Knife edges

35e, 35e on both sides across the central axis CL constitute both ends of the nozzle tip edge 35 in the x direction.

The angle θ formed by the central axis CL and the inclined side surface 34 is preferably θ = 60 ° or less. From the viewpoint of processing uniformity, the smaller the angle θ, the better. On the other hand, if θ is too small, processing of the nozzle 30 becomes difficult. Therefore, the angle θ is more preferably about θ = 20 ° to 30 °. By setting the lower limit of the angle θ to about 20 °, the processing of the nozzle 30 can be facilitated.

The horizontal distance L from the upper end of the inclined side surface 34 to the inner surface of the blowing hole 31 is preferably as small as possible from the viewpoint of processing uniformity. On the other hand, if the distance L is too small, it is difficult to process the nozzle 30. The horizontal distance L considering the processing of the nozzle 30 is preferably about L = 10 mm to 30 mm. The vertical height h of the inclined side surface 34 is preferably as large as possible from the viewpoint of processing uniformity, and for example, h = 10 mm or more is preferable.

The reaction field 1a is defined between the nozzle tip edge 35 and the virtual plane PL. The reaction field 1a has substantially the same width as the nozzle tip edge 35 in the x direction and has substantially the same length as the nozzle tip edge 35 in the y direction (the direction perpendicular to the plane of FIG. 1). That is, the reaction field 1a has a very small dimension in the x direction (extremely thin) and extends long in a straight line in the y direction. The width of the reaction field 1a in the x direction is, for example, about 2 mm. When the substrate 9 to be processed crosses the reaction field 1a, an etching reaction of the silicon-containing film 9a on the surface of the substrate 9 to be processed occurs in the reaction field 1a.

The gap g1 between the nozzle tip edge 35 and the upper surface of the substrate 9 to be processed is preferably g1 = 1 mm to 10 mm, and more preferably g1 = 3 mm to 7 mm.

A diffusion space 1e is defined between each of the pair of inclined side surfaces 34 of the nozzle 30 and the virtual plane PL. As a result, a diffusion space 1 e is defined between each inclined side surface 34 and the substrate 9 to be processed. A pair of diffusion spaces 1e sandwich the reaction field 1a from both sides in the x direction. Each diffusion space 1e extends by the same length as the inclined side surface 34 in the y direction. Each diffusion space 1e is connected to the reaction field 1a and expands in the vertical direction (direction perpendicular to the virtual plane PL) as it moves away from the reaction field 1a in the x direction, and the peripheral space of the nozzle 30 in the processing tank 2 It is connected to. The reaction field 1a and the diffusion space 1e are at a pressure near atmospheric pressure.

As shown in FIG. 1, a rectifying plate 40 is provided immediately below the nozzle 30. The rectifying plate 40 is disposed between the two rollers 22 adjacent in the x direction. As shown in FIGS. 1 and 2, the rectifying plate 40 has a flat plate shape that is horizontally oriented along the virtual plane PL and that extends long in the y direction. The central portion in the x direction of the rectifying plate 40 just intersects the central axis CL of the nozzle 30. The size of the rectifying plate 40 in the x direction is larger than the size of the nozzle 30 in the x direction, and both end portions of the rectifying plate 40 in the x direction extend from the pair of inclined side surfaces 34 and 34 to both sides in the x direction. The dimension of the rectifying plate 40 in the y direction is larger than the dimension of the substrate 9 to be processed in the y direction, and further larger than the dimension of the blowing hole 31 in the y direction. Both ends of the rectifying plate 40 in the y direction protrude outward in the y direction from the substrate 9 to be processed, and further protrude outward in the y direction from the blowout holes 31. As shown in FIG. 1, the upper surface of the rectifying plate 40 is located slightly below the virtual plane PL. As shown in FIG. 4, the gap g2 between the virtual plane PL and the upper surface of the rectifying plate 40 is preferably about g2 = 1 mm to 3 mm. The nozzle 30 and the current plate 40 face each other up and down across the virtual plane PL. Both end surfaces of the rectifying plate 40 in the x direction are downward inclined surfaces.

The operation of the etching apparatus 1 configured as described above will be described.
The substrate 9 to be processed is transported along the x direction by the roller conveyor 20. At the same time, the fluorine-based source gas (CF ₄ + Ar + H ₂ O) from the

supply units

14 and 15 is turned into plasma by the plasma generation unit 11, and the ozone-containing gas (O ₂ + O ₃ ) from the ozonizer 16 is mixed therewith. Process gas is obtained. After this processing gas is made uniform in the y direction by the rectifying unit (not shown), it is introduced into the blowing hole 31 and blown out from the tip (lower end) of the blowing hole 31. The average blowing flow rate of the processing gas in the blowing holes 31 is preferably 0.1 m / s to 1.0 m / s, more preferably 0.2 m / s to 0.6 m / s. It is possible to prevent the airflow in the processing tank 2 from being disturbed by suppressing the blowout flow rate to be small. The blowing flow rate can be adjusted by the supply flow rate of the processing gas.

The processing gas contacts the substrate 9 to be processed in the reaction field 1 a immediately below the nozzle tip edge 35. This processing gas causes an etching reaction in the reaction field 1a. Specifically, the amorphous silicon film 9a is oxidized by O ₃ in the processing gas, and further reacted with HF to be converted into a volatile component such as SiF ₄ . As a result, the portion of the amorphous silicon film 9a disposed in the reaction field 1a can be etched.

As shown by a thick arrow f in FIG. 4, the processing gas diffuses into the diffusion space 1e immediately after contacting the substrate 9 to be processed in the reaction field 1a. Since the diffusion space 1e is greatly expanded as it moves away from the reaction field 1a, almost no diffusion resistance is generated. Therefore, even if the blowing speed of the processing gas is small, the processing gas blown earlier can be easily pushed out from the reaction field 1a by the newly blown flow. Therefore, in the reaction field 1a, fresh process gas is always in contact with the substrate 9 to be processed. Therefore, it is possible to prevent the concentration of the reaction components in the reaction field 1a (HF and O ₃₎ to decrease, thereby improving the etching rate.

Most of the etching reaction occurs locally only in the narrow reaction field 1a. The local etching rate in the reaction field 1a is such that the central part of the substrate 9 to be processed is located in the reaction field even when the front end of the substrate 9 to be processed is located in the reaction field 1a. Even when the rear end of the substrate 9 in the traveling direction is located in the reaction field, it is almost uniform. In the diffusion space 1e, the processing gas is sufficiently diffused and the concentration of the reaction component is greatly reduced, so that the etching reaction hardly occurs on the surface of the substrate 9 in the diffusion space 1e. In addition, since the rectifying plate 40 extends outward in the x direction from the pair of inclined side surfaces 34, the flow state of the processing gas in the diffusion space 1 e is also kept almost constant regardless of the traveling position of the substrate 9 to be processed. be able to. As a result, the entire substrate 9 can be etched uniformly. Furthermore, combined with the effect of preventing the turbulence of the airflow in the processing tank 2 due to the low blowout flow rate, the processing uniformity can be further improved.

The diffused treated gas is exhausted by an exhaust means (not shown).

Next, another embodiment of the present invention will be described. In the following embodiments, the same reference numerals are given to the drawings for the configurations already described, and the description thereof is omitted.
5 to 10 show modified examples of the shape of the nozzle 30. FIG. As shown in FIG. 5, the nozzle tip edge 35 </ b> A may be slightly flattened (cut flat) to have a planar shape. Even in this case, it is preferable that the width of the tip edge 35A in the x direction is as small as possible. The width w2 from the inner surface of the blowing hole 31 to the outer end of the planar tip edge 35A is preferably w2 ≦ 2 mm, more preferably w2 <1 mm. The reaction field 1a is defined between the tip edge 35A of the nozzle 3 and the virtual plane PL, and thus is defined between the tip edge 35A and the substrate 9 to be processed. The width of the reaction field 1a in the x direction is substantially equal to the width of the nozzle tip edge 35A in the x direction and is larger than the width of the blowing hole 31 in the x direction.

The inclined side surface 34 may not be a flat surface. As shown in FIG. 6, the inclined side surface 34 may be a gentle concave curved surface. As shown in FIG. 7, the inclined side surface 34 may be a gently convex curved surface. As shown in FIG. 8, a convex portion 36 may be formed on the inclined side surface 34. As shown in FIG. 9, a concave portion 37 such as a groove may be formed on the inclined side surface 34. The convex portion 36 or the concave portion 37 may have a spot shape, or may have a bead shape or a stripe shape extending in the vertical direction or the y direction. The number of the convex portions 36 or the concave portions 37 may be one or plural.

In the second embodiment shown in FIGS. 10 and 11, a pair of suction holes 39 are formed inside the nozzle 30. The pair of suction holes 39 are provided on both sides in the x direction with the blowout hole 31 in between. Each suction hole 39 has a slit shape extending in the y direction, and is inclined so as to approach the central blowing hole 31 as it goes downward. The lower end portion (suction port) of each suction hole 39 reaches the nozzle tip edge 35 and opens. The inner surface of each suction hole 39 on the central axis CL side and the inner surface of the blowing hole 31 intersect at an acute angle at the nozzle tip edge 35. At the nozzle tip edge 35, the blowout holes 31 and the suction holes 39 on both sides thereof are arranged in contact with each other. The width of each suction hole 39 in the x direction is smaller than the width of the blowing hole 31 in the x direction (for example, about 2 mm), and preferably about one half (for example, 1 mm) of the width of the blowing hole 31 in the x direction. The width of each suction hole 39 in the x direction may be substantially equal to the width of the blowing hole 31 in the x direction, or may be larger than the width of the blowing hole 31 in the x direction. The suction hole 39 may be configured by a plurality of small holes arranged in the y direction.

A suction port 38 is provided in the upper portion 32 of the nozzle 30. The upper end portion of the suction hole 39 is connected to the suction pump 4 (gas suction means) via the suction port 38.

The inclined side surface 34 of the nozzle 30 changes discontinuously in the vicinity of the tip edge 35, and a ridge line 34c is formed. Below the ridge line 34c, the inclination is small with respect to the virtual plane PL.

According to this embodiment, in parallel with the supply of the processing gas to the nozzle 30, the gas near the lower end opening of the suction hole 39 is locally sucked into the suction hole 39 by the suction pump 4. For this reason, the processing gas is blown out from the blowing hole 31 and comes into contact with the substrate 9 immediately under the processing gas, and is immediately sucked into the suction hole 39. Therefore, it is possible to more reliably prevent the treated gas from staying in the reaction field 1a. Thereby, in the reaction field 1a, the to-be-processed substrate 9 can be surely brought into contact with only a fresh process gas, and the decrease in the concentration of the reaction components in the reaction field 1a can be prevented more reliably. Furthermore, the flow of the processing gas in the reaction field 1a can be made uniform regardless of the position of the substrate 9 in the traveling direction. Therefore, the uniformity of the etching process can be further improved.

In the third embodiment shown in FIG. 12, three (plural) nozzles 30 are provided. Three nozzles 30 are arranged at intervals in the x direction. The processing gas is distributed to the blowing holes 31 of each nozzle 30. A rectifying plate 40 is disposed immediately below each nozzle 30. Corresponding nozzles 30 and rectifying plates 40 face each other up and down across the virtual plane PL. The configuration of each nozzle 30 is the same as that of the first embodiment, such that each nozzle 30 extends in the y direction (the direction orthogonal to the plane of FIG. 12), and the lower portion 33 is tapered.

According to the present invention, even when a plurality of nozzles 30 are arranged in the x direction, streaky process unevenness extending in the y direction on the substrate 9 to be processed is prevented from being formed at the same interval as the arrangement interval of the nozzles 30. Or it can be suppressed.

FIG. 13 shows a fourth embodiment of the present invention. In this embodiment, the nozzles at both ends in the x direction in the third embodiment (FIG. 12) are exhaust nozzles 50. The shape of the exhaust nozzle 50 is substantially the same as that of the processing gas blowing nozzle 30. That is, the exhaust nozzle 50 has a pair of inclined side surfaces 54 and 54 on both sides in the x direction and a leading edge 55 that faces the virtual plane PL, and extends long in the y direction (width direction orthogonal to the paper surface of FIG. 13). ing. The inclined side surfaces 54 and 54 approach each other as they approach the tip edge 55. The tip edge 55 is very thin and extends linearly in the y direction. A cross section perpendicular to the y direction of the lower portion 53 of the exhaust nozzle 50 is tapered so as to point toward the virtual plane PL.

An exhaust hole 51 is formed in the exhaust nozzle 50. The suction path 5 is connected to the upper end of the exhaust hole 51. A suction path 5 is connected to the gas suction means 4. The lower end of the exhaust hole 51 opens at the tip edge 55 and is distributed in a slit shape over substantially the entire length of the nozzle 50 in the longitudinal direction (y direction perpendicular to the paper surface of FIG. 13). The exhaust hole 51 may be configured by a large number of small holes arranged in the y direction instead of the slit shape.

The blowout nozzle 30 is disposed just in the middle between the

exhaust nozzles

50 and 50 at both ends. The distance from the center axis CL of the blowout nozzle 30 to the center axis _{CL 50} of the exhaust nozzle 50 is, for example, several tens of mm ~ several hundred mm, where is about 100 mm.

Note that the blowout nozzle 30 may be arranged so as to be biased toward one of the exhaust nozzles 50. For example, the

exhaust nozzle

50, 50 if just when the distance from the intermediate position to the center axis _{CL 50} of one of the exhaust nozzle 50 is about 100 mm, a blow nozzle 30, several tens mm (preferably from the intermediate position 20mm ) It may be arranged so as to be biased toward the one exhaust nozzle 50 within a range of about.

In the fourth embodiment, the gas around the

exhaust nozzles

50, 50 at both ends is sucked into the exhaust hole 51 by driving the suction exhaust unit 4. In particular, the gas around the lower end of each exhaust nozzle 50, that is, the tip edge 55 is sucked into the exhaust hole 51. This suction flow can stabilize the gas flow f in the space between each exhaust nozzle 50 and the central blowing nozzle 30, and can further improve the uniformity of processing.

The present invention is not limited to the above embodiment, and various modifications can be adopted without departing from the spirit of the present invention.
For example, the conveying unit may be connected to the nozzle 30. The substrate to be processed 9 may be stopped by moving the nozzle 30 in the transport direction.
The rectifying plate 40 may be omitted.

The gap g1 between the tip edge of the nozzle 30 and the upper surface of the substrate 9 to be processed may be made relatively large. This makes it easier to diffuse the processing gas from the reaction field 1a to the diffusion space 1e. For example, in the above embodiment, the preferred range of the gap g1 is g1 = 1 mm to 10 mm, but it may be about g1 = 10 mm to 30 mm.

A plurality of embodiments may be combined with each other. For example, the plurality of nozzles 30 shown in FIG. 12 may be constituted by the nozzles 30 with the suction holes 39 shown in FIG. 10, or may be constituted by the deformed nozzles 30 shown in FIGS. The shape of the exhaust nozzle 50 (FIG. 13) may be similar to the shape of the blowout nozzle 30 of FIGS.

Examples will be described. Needless to say, the present invention is not limited to the following examples.
The amorphous silicon film 9a on the surface of the glass substrate 9 was etched using the etching apparatus 1 shown in FIG. The vertical dimension of the entire nozzle 30 was 55 mm, and the vertical height h of the inclined side surface 34 was h = 30 mm. The horizontal distance L from the upper end of the inclined side surface 34 to the inner surface of the blowing hole 31 was L = 10 mm. The angle θ of the inclined side surface 34 with respect to the vertical surface was θ = 20 ° slightly. The width of the blowing hole 31 in the x direction was 2 mm. The length of the blowout hole 31 in the y direction was 600 mm, which was 100 mm larger than the dimension of the glass substrate 9 in the y direction. Each end portion in the y direction of the blowing hole 31 protruded 50 mm outward from the glass substrate 9 in the y direction. The dimension of the upper surface of the current plate 40 in the x direction was 63 mm.

The fluorine-based raw material gas components of the processing gas were as follows.
CF ₄ 0.8 slm
Ar 16.2 slm
Water (H ₂ O) was added to the mixed gas of CF ₄ and Ar so that the dew point was 13 ° C. The added gas was turned into plasma in the plasma generation unit 11. The power supplied from the power source 3 was 450 V and 9.0 A in direct current, and this was converted into a high-frequency pulse voltage of Vpp = 12 kV and 25 kHz and supplied to the electrode 12. Furthermore, the ozone-containing gas from the ozonizer 16 was mixed with the fluorinated gas after being converted to plasma to obtain a processing gas. The flow rate of the ozone-containing gas was 12.68 slm, and the ozone concentration was 230 g / m ³ . This processing gas was blown out from the blowing hole 31 of the nozzle 30. The blowing flow rate was 0.4 m / s.

The glass substrate 9 was transported in the x direction at a transport speed of 4 m / min, and was brought into contact with the processing gas in the reaction field 1a immediately below the tip edge of the nozzle 30. The number of times the glass substrate 9 was passed through the reaction field 1a (number of scans) was three. The gap g1 between the tip edge of the nozzle 30 and the upper surface of the substrate 9 to be processed was g1 = 7 mm. As a result, the amorphous silicon film 9a on the surface of the substrate 9 to be processed was uniformly etched. Processing unevenness depending on the position of the substrate 9 to be processed was not formed, and no stripe-shaped processing unevenness extending in the y direction was formed.

The present invention is applicable to the manufacture of semiconductor devices and liquid crystal display devices.

DESCRIPTION OF SYMBOLS 1 Etching apparatus 1a Reaction field 1e Diffusion space 2 Processing tank 3 Power supply 4 Suction pump (gas suction means)
9 Substrate 9a Silicon-containing material 10 Processing gas supply unit 11 Plasma generation unit 12 Electrode 13 Discharge space (interelectrode space)
14 Fluorine raw material supply unit 15 Addition unit 16 Ozonizer (oxidation reaction component supply unit)
19 Supply path 20 Roller conveyor (support, transport means)
21 Shaft 22 Roller 30 Nozzle 31 Blowout hole 32 Upper part 33 Lower part 34 Inclined side surface 35 Tip edge 35A Plane tip edge 35e Knife edge 36 Convex part 37 Concave port 39 Suction port 39 Suction hole 40 Rectifier plate 50 Exhaust nozzle 51 Exhaust Hole 53 Lower portion 54 Inclined side surface 55 Tip edge CL Center axis PL Virtual plane

Claims

In an etching apparatus for etching a silicon-containing material by bringing a processing gas containing a fluorine-based reaction component into contact with a substrate to be processed containing the silicon-containing material under atmospheric pressure,
A support unit for supporting the substrate to be processed on a virtual plane;
A nozzle having a blowing hole for blowing out the processing gas and extending in the width direction of the virtual plane;
Transport means for moving the substrate to be processed relative to the nozzle in the transport direction along the virtual plane and perpendicular to the width direction;
The nozzle includes a tip edge that is extremely thin and extends in the width direction, and inclined side surfaces that form a pair on both sides in the transport direction and approach each other as they approach the tip edge. A cross section perpendicular to the direction is pointed toward the virtual plane, the blowing holes are distributed in the width direction and open to the tip edge, and a reaction field is defined between the tip edge and the virtual plane. In addition, a diffusion space is formed between the pair of inclined side surfaces and the virtual plane so as to expand in a direction orthogonal to the virtual plane as the distance from the reaction field increases in the transport direction. Etching equipment.
2. The etching apparatus according to claim 1, wherein an average blowing flow rate of the processing gas in the blowing hole is 0.1 m / s to 1.0 m / s.
3. The etching apparatus according to claim 1, wherein an average blowing flow rate of the processing gas in the blowing hole is 0.2 m / s to 0.6 m / s.
4. The nozzle according to claim 1, wherein a suction hole connected to the gas suction means is formed in the nozzle, and the suction hole is opened at the tip edge so as to be in contact with the blowout hole. 2. The etching apparatus according to item 1.
A rectifying plate facing the nozzle across the virtual plane is provided along the virtual plane, and the rectifying plate extends from the pair of inclined side surfaces to both sides in the transport direction. Item 5. The etching apparatus according to any one of Items 1 to 4.
The apparatus further includes a processing gas supply unit that supplies the processing gas to the nozzle, and the processing gas supply unit includes a plasma generation unit that includes a pair of electrodes that generate a discharge under atmospheric pressure between each other, and contains fluorine 6. The fluorine-based reaction component is generated by introducing a raw material gas containing a component and a hydrogen-containing additive component into the space between the pair of electrodes to generate plasma. 2. The etching apparatus according to item 1.