WO2012043383A1

WO2012043383A1 - Etching method, and device

Info

Publication number: WO2012043383A1
Application number: PCT/JP2011/071638
Authority: WO
Inventors: 俊介功刀; 真弓　聡
Original assignee: 積水化学工業株式会社
Priority date: 2010-09-28
Filing date: 2011-09-22
Publication date: 2012-04-05
Also published as: KR101362632B1; TWI428983B; CN103155116B; KR20130052034A; CN103155116A; JPWO2012043383A1; TW201216361A; JP5276223B2

Abstract

To easily control the amount of etching on a silicon-containing material. In a pre-treatment step, a treatment fluid containing a second oxidative reaction component is sprayed from a pre-treatment nozzle (42) and is brought into contact with an object (9) to be treated. Subsequently, in an etching treatment step, while the object (9) to be treated is moved in a moving mechanism (20) so as to cut across a treatment space (39), a treatment gas containing a fluorine reaction component and a first oxidative reaction component is supplied to the treatment space (39) and is brought into contact with the object (9) to be treated.

Description

Etching method and apparatus

The present invention relates to a method and apparatus for etching a silicon-containing material, and more particularly, to an etching method and apparatus suitable for controlling the etching amount of a silicon-containing material that is etched with an oxidation reaction of amorphous silicon or the like.

An apparatus for etching a silicon-containing material such as amorphous silicon using plasma near atmospheric pressure is known (see Patent Documents 1 and 2). For example, in Patent Document 1, a gas in which water vapor is added to a fluorine-containing component such as CF _{4 is} converted into plasma under atmospheric pressure. Fluorine-based reaction components such as HF and COF ₂ are generated by plasmatization. Ozone is further mixed with the gas after being plasmatized and brought into contact with the object to be processed. Thereby, the silicon coated on the object to be processed is etched through the following two-stage reaction process.

In the first stage, an oxidation reaction of silicon occurs (Equation 1).
3Si + 2O ₃ → 3SiO ₂ (Formula 1)
In the second stage, the oxidized silicon reacts with a fluorine-based reaction component such as HF, and is converted into a volatile component (SiF ₄ or the like).
SiO ₂ + 4HF → SiF ₄ + 2H ₂ O (Formula 2)
On the surface of the object to be processed, HF and H ₂ O in the processing gas are condensed to form a condensed layer of hydrofluoric acid water.

In Patent Document 2, a plasma gas containing a fluorine-based reaction component and an ozone-containing gas are blown out from separate blowout ports and brought into contact with the object to be processed. The workpiece is reciprocated (scanned) with respect to the gas blowing nozzle. Here, one-way movement to the forward side or the backward side is defined as one scan. One reciprocating movement is two scans.

JP 2007-294642 A JP 2009-099880 ([0023], FIG. 2)

In an etching process using a processing gas containing a fluorine-based reactive component such as HF and an oxidizing reactive component such as ozone, when the workpiece crosses the processing space for the first time (at the first crossing, the first scan) After that, the etching rate is lower than when the workpiece crosses the processing space (at the second and subsequent crossings, the second and subsequent scans). At the first crossing, the second stage etching reaction (Equation 2) does not start until after the first stage oxidation reaction (Equation 1) occurs. Therefore, the fluorine-based reaction component is wasted. In addition, a condensed layer of hydrofluoric acid water or the like resulting from the fluorine-based reaction component is formed on the surface of the object to be processed, and this condensed layer obstructs the oxidation reaction, so that the etching reaction becomes more difficult to occur. In the second and subsequent crossings, the surface of the object to be processed has already been oxidized by the processing up to the previous time, so that the second stage etching reaction (Equation 2) can be started immediately. For this reason, the number of times the workpiece crosses the processing space (the number of crossings, the number of scans) and the cumulative etching amount are not directly proportional, the proportionality is inferior, and the etching amount is not easily controlled.
The present invention has been made based on the above circumstances, and prevents the fluorine-based reaction component from being wasted by making the etching reaction of the silicon-containing material sufficiently occur from the first crossing, and the etching amount. It is intended to make it possible to easily control.

In order to achieve the above object, an etching method according to the present invention etches a silicon-containing material using a processing gas containing a fluorine-based reaction component and a first oxidizing reaction component in a processing space near atmospheric pressure. In the method
A pretreatment step of bringing a treatment fluid containing a second oxidizing reaction component into contact with an object to be treated containing the silicon-containing material;
After the pretreatment step, supply the processing gas to the processing space while moving the object to be processed relative to the processing space so as to cross (pass) the processing space, or An etching process step for generating each reaction component of the process gas in a processing space;
It is characterized by including.

In the pretreatment process, the second oxidizing reaction component in the processing fluid causes an oxidation reaction with the silicon-containing material (see Formula 1). Subsequently, when the object to be processed first traverses the processing space in the etching process (at the first crossing (at the time of passage), the first scan), the oxidation reaction of the silicon-containing material has already progressed through the pretreatment process. Yes. Therefore, the etching reaction (see Formula 2) by the fluorine-based reaction component in the processing gas can be started immediately. Therefore, the etching rate can be sufficiently increased even at the first crossing, and the waste of the fluorine-based reaction component can be avoided. Furthermore, when the first oxidative reaction component in the processing gas contacts the object to be processed at the time of the first crossing, the oxidation of the silicon-containing material can be further advanced. At the time of the second and subsequent crossings, the surface of the silicon-containing material has already been oxidized by the previous crossings, so that the etching reaction due to the fluorine-based reaction component in the processing gas can be caused immediately. In addition, the silicon-containing material can be further oxidized by the first oxidizing reaction component in the processing gas. Therefore, the etching rate at the first crossing and the etching rate at the second and subsequent crossings can be made substantially the same. Therefore, the proportionality between the number of crossings and the cumulative etching amount can be increased. Therefore, by setting the number of crossings, it is possible to easily control the final etching amount of the silicon-containing material to a desired value.

In the etching process, it is preferable to control the etching amount of the silicon-containing material by adjusting the number of times that the workpiece crosses the processing space (number of times of crossing). When the number of crossings reaches the set number, the etching process is stopped. As a result, the silicon-containing material can be reliably etched to a desired thickness. The etching can be stopped when the remaining thickness of the silicon-containing film reaches a predetermined value, or the etching can be stopped when the entire silicon-containing film has just been removed. According to the present invention, it is possible to easily determine the timing for stopping etching.

The silicon-containing material is preferably one that causes an etching reaction (see Formula 2) with a fluorine-based reaction component with an oxidation reaction (see Formula 1), such as amorphous silicon, single crystal silicon, polycrystalline silicon, etc. Examples include silicon alone, silicon nitride, and silicon carbide.
Examples of the fluorine-based reaction component in the processing gas include HF, COF _{2 and the} like.
Examples of the first oxidizing reaction component in the processing gas include O ₃ , O radical, NOx, and the like.
Examples of the second oxidizing reaction component in the processing fluid include O ₃ , O radical, and NOx. The processing fluid is not limited to gas, and may be liquid such as ozone water, nitric acid, hydrogen peroxide and the like.

In the etching treatment step, it is preferable that the fluorine-based reaction component is generated by converting the fluorine-based source gas containing a fluorine-containing component and a hydrogen-containing additive component into plasma at a pressure near atmospheric pressure.
Thereby, HF etc. can be produced | generated as a fluorine-type reaction component. In the etching process, a condensed layer of hydrofluoric acid water or the like resulting from the fluorine-based reaction component is formed on the surface of the object to be processed. An etching reaction is performed through this condensed layer. On the other hand, in the pretreatment step, the condensed layer is not formed, so that the condensed layer does not interfere with the oxidation reaction, and the oxidation reaction can be caused reliably.
Examples of the fluorine-containing component include fluorine-containing compounds such as PFC (perfluorocarbon) and HFC (hydrofluorocarbon). Examples of the PFC include CF ₄ , C ₂ F ₄ , C ₂ F ₆ , C ₃ F _{8 and the} like. Examples of HFC include CHF ₃ , CH ₂ F ₂ , CH ₃ F and the like. Furthermore, fluorine-containing compounds other than PFC and HFC such as SF ₆ , NF ₃ , and XeF ₂ may be used as the fluorine-based component, and F ₂ may be used.
The fluorine-containing component is preferably diluted with a diluent component. Examples of the dilution component include rare gases such as helium, argon, neon, and xenon, and inert gases such as nitrogen. In addition to the function of diluting the fluorine-containing component, the dilution component has a function as a carrier gas for transporting the fluorine-containing gas and a function as a discharge gas for generating stable plasma discharge.
The hydrogen-containing additive component is preferably water (water vapor, H ₂ O). Water can be added to the fluorine-based raw material gas by vaporizing with a vaporizer. In addition to water, the hydrogen-containing additive component may be an OH group-containing compound, hydrogen peroxide, or a mixture thereof. Examples of the OH group-containing compound include alcohol.
In this specification, the vicinity of 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 ⁴ ˜10.664 × 10 ⁴ Pa is preferable, and 9.331 × 10 ⁴ to 10.397 × 10 ⁴ Pa is more preferable.

An etching apparatus according to the present invention is an etching apparatus for etching a silicon-containing material using a processing gas containing a fluorine-based reaction component and a first oxidizing reaction component in a processing space near atmospheric pressure.
A pretreatment section having a pretreatment nozzle for blowing out a treatment fluid containing a second oxidizing reaction component, and bringing the treatment fluid into contact with an object to be treated containing the silicon-containing material;
An image forming unit that defines the processing space; and a moving mechanism that moves the object to be processed after contact with the processing fluid relative to the image forming unit so as to cross the processing space. An etching processing unit that supplies the processing gas to the processing space or generates the reaction components of the processing gas in the processing space;
It is provided with.

When the silicon-containing material is etched by the etching apparatus, the object to be processed is first arranged in the pretreatment section and is opposed to the pretreatment nozzle. Then, the processing fluid is blown out from the preprocessing nozzle and brought into contact with the object to be processed. The silicon-containing material can be oxidized by the second oxidizing reaction component in the processing fluid (see Formula 1). Next, the object to be processed is placed in the etching processing unit, and the moving unit is moved back and forth with respect to the defining unit. Each time the workpiece passes through the processing space, it contacts the processing gas in the processing space. When the object to be processed first traverses the processing space (at the first crossing), the oxidation reaction of the silicon-containing material has already progressed by the pretreatment in the pretreatment section. Therefore, the etching reaction (see Formula 2) by the fluorine-based reaction component in the processing gas can be started immediately. Therefore, the etching rate can be sufficiently increased even at the first crossing, and the waste of the fluorine-based reaction component can be avoided. Furthermore, when the first oxidative reaction component in the processing gas comes into contact with the object to be processed at the first crossing, the oxidation of the silicon-containing material can be further advanced. At the time of the second and subsequent crossings, the surface of the silicon-containing material has already been oxidized by the previous crossings, so that an etching reaction due to the fluorine-based reaction component in the processing gas can be immediately caused. In addition, the silicon-containing material can be further oxidized by the first oxidizing reaction component in the processing gas. Therefore, the etching rate at the first crossing and the etching rate at the second and subsequent crossings can be made substantially the same. Therefore, the proportionality between the number of crossings and the cumulative etching amount can be increased. Therefore, by setting the number of times of traversal, the final etching amount of the silicon-containing material can be easily controlled so as to become a desired value.
The etching apparatus may include a plurality of the defining units. The plurality of defining units may be arranged in the relative movement direction of the workpiece. As a result, a plurality of processing spaces may be arranged in the relative movement direction. By moving the object to be processed relative to the relative movement direction by the moving mechanism, the object to be processed sequentially traverses the plurality of processing spaces. An operation in which the workpiece crosses one of the plurality of processing spaces corresponds to one crossing (one scan).
The defining unit may include a processing nozzle that blows out the processing gas.

According to the present invention, the etching reaction of the silicon-containing material in the etching processing section or the etching processing process can be sufficiently caused from the first crossing. Therefore, it is possible to prevent the fluorine-based reaction component at the first crossing from being wasted. In addition, the proportionality between the number of crossings and the cumulative etching amount can be increased, and the etching amount can be easily controlled.

It is a side view showing a schematic structure of an etching device concerning a 1st embodiment of the present invention. It is a side view which shows schematic structure of the etching apparatus which concerns on 2nd Embodiment of this invention. It is a side view which shows schematic structure of the etching apparatus which concerns on 3rd Embodiment of this invention. It is a schematic block diagram of the etching apparatus which concerns on 4th Embodiment of this invention. 3 is a graph showing the results of Example 1.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an etching apparatus 1 according to the first embodiment of the present invention. The workpiece 9 is formed of, for example, a glass substrate of a liquid crystal display panel and has a thin flat plate shape. A surface of the workpiece 9 (upper surface in FIG. 1) is coated with a silicon-containing material 9a to be etched. The silicon-containing material is made of, for example, amorphous silicon. In addition to amorphous silicon, the silicon-containing material 9a may be single crystal silicon or polycrystalline silicon. Furthermore, the silicon-containing material 9a is not limited to silicon alone, and may be silicon nitride, silicon carbide, or the like as long as it is etched (formula 2) through an oxidation reaction (formula 1).

The etching apparatus 1 includes a processing chamber 10, a roller conveyor 20 (movement mechanism), a preprocessing unit 40, and an etching processing unit 30. The pressure in the processing chamber 10 is near atmospheric pressure. A carry-in port 11 is provided on a wall on the entry side (right side in FIG. 1) of the processing chamber 10. A carry-out port 12 is provided on the exit side wall (left side in FIG. 1) of the processing chamber 10. An etching processing unit 30 is incorporated in the central portion of the processing chamber 10. A pretreatment unit 40 is incorporated in a portion on the entry side (right side in FIG. 1) in the treatment chamber 10.

The roller conveyor 20 is arranged inside the processing chamber 10 along the feeding direction (x direction, left-right direction in FIG. 1), and is also installed outside the processing chamber 10 on the entry side and the exit side. 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 right and left in FIG. Each shaft 21 is provided with a roller 22.

The workpiece 9 is placed on the roller 22. As the shaft 21 and the roller 22 rotate together, the workpiece 9 is conveyed in the x direction. The workpiece 9 is carried into the processing chamber 10 from the carry-in port 11, subjected to a predetermined process in the processing chamber 10, and then carried out from the carry-out port 12. The conveyor 20 has a function as a support part for supporting the object 9 to be processed and a function as a moving mechanism for moving the object 9 to be processed.

In the roller conveyor 20, at least the shaft 21 and the roller 22 in the processing chamber 10 are rotatable in both forward and reverse directions. The forward direction is the direction in which the workpiece 9 is conveyed from the entry side to the exit side (leftward in FIG. 1), and the reverse direction is the direction in which the workpiece 9 is conveyed from the exit side to the entry side (rightward in FIG. 1). ).

The etching processing unit 30 includes a fluorine-based raw material supply unit 31, a first oxidizing reaction component generation unit 32, and a main processing nozzle 33. The fluorine-based material supply unit 31 stores a fluorine-based material gas. The fluorine-based source gas includes a fluorine-containing component and a dilution component. The fluorine-containing component is, for example, CF ₄ . The dilution component is, for example, Ar.

As the fluorine-containing component, other PFC (perfluorocarbon) such as C ₂ F ₄ , C ₂ F ₆ , C ₃ F ₈ may be used instead of CF ₄ , and CHF ₃ , CH ₂ F ₂ , CH ₃ may be used. HFC (hydrofluorocarbon) such as F may be used, and SF ₆ , NF ₃ , XeF ₂ , F _2, etc. may be used.

As a dilution component, instead of Ar, other rare gases such as He, Ne, and Kr may be used, and other inert gases such as N ₂ may be used. 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.

An addition unit 34 is added to the fluorine-based raw material supply unit 31. The hydrogen-containing additive component of the addition unit 34 is added to the fluorine-based source gas of the fluorine-based source supply unit 31. The hydrogen-containing additive component is water vapor (H ₂ O). The addition part 34 is comprised with the vaporizer of water. Water is stored in the vaporizer 34 in a liquid state. Fluorine-based source gas (CF ₄ + Ar) is introduced into the liquid in the vaporizer 34 and bubbled. Alternatively, the fluorine-based raw material gas may be introduced into the upper part of the liquid level in the vaporizer 34, and the saturated vapor in the upper part may be pushed out by the fluorine-based raw material gas. As a result, water vapor is added to the fluorine-based source gas. By adjusting the temperature of the vaporizer 34, the vapor pressure of water and thus the amount added can be adjusted. Alternatively, a part of the fluorine-based source gas (CF ₄ + Ar) is introduced into the vaporizer 34, the remainder is bypassed by the vaporizer 34, and the amount of water added is adjusted by adjusting the flow rate ratio between the part and the remainder. May be adjusted. The fluorine-based source gas after the addition of water is sent to the main processing nozzle 33.

The 1st oxidizing reaction component production | generation part 32 is comprised with the ozonizer. The ozonizer 32 generates ozone-containing gas (O ₂ + O ₃ ) using oxygen (O ₂ ) as a raw material. Ozone in the ozone-containing gas _{_{(O 2 + O 3) (}} O 3) corresponds to the "first oxidation reaction component" in the claims. The ozone-containing gas (O ₂ + O ₃ ) from the ozonizer 32 is sent to the main processing nozzle 33.

The main processing nozzle 33 is installed at the center of the processing chamber 10 and extends in the width direction (y direction) orthogonal to the paper surface of FIG. A plasma generation unit 35 (fluorine-based reaction component generation unit) is provided inside the main processing nozzle 33. The plasma generation unit 35 includes at least a pair of electrodes 36. A solid dielectric layer is provided on both or one opposing surface of the pair of electrodes 36. A power source (not shown) is connected to one electrode 36 of the pair of electrodes 36, and the other electrode 36 is electrically grounded. For example, a pulsed high-frequency electric field is applied between the pair of electrodes 36 by supplying power from the power source. As a result, a glow discharge is generated between the electrodes 36 near atmospheric pressure.

A fluorine-based raw material supply unit 31 is connected to a space 36 a between the electrodes 36. The fluorine-based source gas (CF ₄ + Ar + H ₂ O) after the addition of water is introduced into the interelectrode space 36a. Thereby, in the interelectrode space 36a, the fluorine-based source gas is turned into plasma (including excitation, decomposition, radicalization, and ionization), and fluorine-based reaction components such as HF and COF ₂ are generated.
The plasma generation unit 35 may be provided on a path between the fluorine-based raw material supply unit 31 and the main processing nozzle 33 instead of inside the main processing nozzle 33.

The plasma-based fluorine-based gas and the ozone-containing gas from the ozonizer 32 are mixed in the main processing nozzle 33 to generate a processing gas. The processing gas contains a fluorine-based reaction component (HF, COF ₂ or the like) and a first oxidizing reaction component (O ₃ ).

Although illustration is omitted, a first rectification unit is provided inside the main processing nozzle 33. The first rectification unit includes a chamber extending in the y direction (a direction orthogonal to the plane of FIG. 1), a slit extending in the y direction, and a large number of small holes arranged in the y direction. The processing gas is made uniform in the y direction by passing through the first rectifying unit.

The lower part of the main processing nozzle 33 is inserted into the processing chamber 10. The main processing nozzle 33 faces the central portion of the roller conveyor 20 in the processing chamber 10 in the vertical direction. A processing space 39 is defined between the main processing nozzle 33 and the conveyor 20 immediately below the main processing nozzle 33. The main processing nozzle 33 constitutes an image forming unit that defines the processing space 39 in cooperation with the roller conveyor 20. A plurality of blowing portions 37 are provided at the lower end of the main processing nozzle 33. The plurality of blowing portions 37 are arranged at intervals in the x direction. In the figure, the number of the blowing portions 37 is three, but may be one or two, or four or more. Each blowing unit 37 faces the processing space 39. Each blowout part 37 includes a slit-like blowout opening 37a extending in the y direction (direction orthogonal to the plane of FIG. 1). The outlet 37a may be configured by a large number of small holes arranged in the y direction. The processing gas after passing through the rectifying unit is distributed to each blowing unit 37 and blown downward from each blowing port 37a. This blowing flow becomes a uniform flow in the y direction. The processing space 39 is a region in the space along the lower surface of the main processing nozzle 33 where the processing gas can diffuse while maintaining effective reactivity.

Next, the preprocessing unit 40 will be described.
The pretreatment unit 40 includes a treatment fluid supply unit 41 and a pretreatment nozzle 42. The processing fluid supply unit 41 is configured by, for example, an ozonizer. The ozonizer 41 generates ozone-containing gas (O ₂ + O ₃ ) using oxygen (O ₂ ) as a raw material. This ozone-containing gas (O ₂ + O ₃ ) corresponds to the “processing fluid” in the claims. Ozone (O ₃ ) in the processing fluid (O ₂ + O ₃ ) constitutes the “second oxidizing reaction component” in the claims. An ozonizer 41 is connected to the pretreatment nozzle 42. The processing fluid (O ₂ + O ₃ ) is introduced from the ozonizer 41 into the preprocessing nozzle 42.

The processing fluid supply unit 41 of the preprocessing unit 40 and the oxidizing reaction component supply unit 32 of the etching processing unit 30 may be shared with each other. For example, a single ozonizer serves as both the ozonizer 32 of the etching processing unit 30 and the ozonizer 41 of the pretreatment unit 40. The ozone-containing gas supply path from this single ozonizer branches into two branch paths. These branch paths may be connected to the main processing nozzle 33 and the preprocessing nozzle 42, respectively.

The pretreatment nozzle 42 is installed at the upper part on the entry side (right side in FIG. 1) in the treatment chamber 10. The pretreatment nozzle 42 extends in the y direction of the etching apparatus 1 (the direction orthogonal to the plane of FIG. 1). Although not shown, a second rectification unit is provided inside the ozonizer 41. The second rectification unit includes a chamber extending in the y direction, a slit extending in the y direction, and a large number of small holes arranged in the y direction. The ozone-containing gas (O ₂ + O ₃ ) from the ozonizer 41 is made uniform in the y direction by passing through the second rectification unit.

The lower part of the pre-processing nozzle 42 is inserted into the processing chamber 10 and vertically opposes the part near the carry-in entrance 11 of the roller conveyor 20 in the processing chamber 10. A preprocessing space 49 is defined between the preprocessing nozzle 42 and the roller conveyor 20 immediately below the preprocessing nozzle 42. A blowing portion 43 is provided at the lower end portion of the pretreatment nozzle 42. The blowing unit 43 faces the preprocessing space 49. The blow-out portion 43 includes a slit-like blow-out port 43a extending in the y direction (a direction orthogonal to the plane of FIG. 1). The outlet 43a may be configured by a large number of small holes arranged in the y direction. The ozone-containing gas after passing through the rectifying unit is sent to the blowing unit 43 and blown downward from the blowing port 43a. This blowing flow becomes a uniform flow in the y direction. The pretreatment space 49 is a region in the space along the lower surface of the pretreatment nozzle 42 where the ozone-containing gas (treatment fluid) can diffuse while maintaining effective reactivity.

The operation of the etching apparatus 1 configured as described above will be described.
[Import process]
The workpiece 9 is carried into the processing chamber 10 from the carry-in entrance 11 by the roller conveyor 20. As a result, the workpiece 9 is first introduced into the pretreatment space 49 and is opposed to the pretreatment nozzle 42. The workpiece 9 crosses the preprocessing space 49.

[Pretreatment process]
In parallel with the above carry-in process, ozone-containing gas (processing fluid) is introduced from the ozonizer 41 to the pretreatment nozzle 42 and blown out from the outlet 43a. This ozone-containing gas comes into contact with the workpiece 9 passing through the pretreatment space 49. Ozone (O ₂ ) in the ozone-containing gas reacts with the silicon-containing material 9a on the surface of the workpiece 9 to oxidize the surface portion of the silicon-containing material 9a (Formula 1). At this stage, since the condensed layer such as hydrofluoric acid water caused by the fluorine-based reaction component is not formed on the surface of the object 9 to be processed, the oxidation reaction of the silicon-containing material 9a can be surely caused.

[Transfer process]
The roller conveyor 20 continuously conveys the workpiece 9 at a constant speed. As a result, the workpiece 9 passes through the preprocessing space 49 and is transferred to the processing space 39. When the entire object 9 has exited the pretreatment space 49, the supply of the ozone-containing gas from the ozonizer 41 is stopped.

[Etching process]
Then, the object 9 is subjected to an etching process. That is, the fluorine-based source gas (CF ₄ + Ar + H ₂ O) from the fluorine-based material supply unit 31 and the addition unit 34 is introduced into the main processing nozzle 33 and is converted into plasma by the plasma generation unit 35 to generate a fluorine-based reaction such as HF. Generate ingredients. The plasma-containing gas is mixed with an ozone-containing gas (O ₂ + O ₃ ) from the ozonizer 32 to obtain a processing gas. This processing gas is blown out from each blowing port 37 a and supplied into the processing space 39.

In parallel with the processing gas supply, the roller conveyor 20 (moving mechanism) in the processing chamber 10 repeats normal rotation and reverse rotation. As a result, the workpiece 9 is reciprocated (scanned) in the processing chamber 10. Every time the workpiece 9 moves one way (one scan) toward the forward side (leftward in FIG. 1) or the backward side (rightward in FIG. 1), the entire workpiece 9 crosses the processing space 39 once. . The workpiece 9 contacts the processing gas from the main processing nozzle 33 when crossing the processing space 39.

When the workpiece 9 first crosses the processing space 39 in the forward direction (at the first crossing, the first scan), the oxidation reaction (formula 1) of the silicon-containing material 9a on the surface layer has already progressed by the pretreatment step. It is out. Therefore, the etching reaction (formula 2) by the fluorine-based reaction component such as HF in the processing gas can be started immediately when the processing gas comes into contact with the workpiece 9. Therefore, the etching rate can be sufficiently increased even at the first crossing, and the waste of the fluorine-based reaction component can be avoided. Furthermore, when the ozone in the processing gas contacts the workpiece 9 during the first crossing, the oxidation of the silicon-containing material 9a (Formula 1) can be further advanced.

During the second and subsequent crossings, the surface of the silicon-containing material 9a has already been oxidized by the previous crossings, so that the processing gas comes into contact with the object 9 to be etched by HF or the like in the processing gas ( Equation 2) can be caused immediately and the etching rate can be made sufficiently high. Furthermore, the oxidation (formula 1) of the silicon-containing material 9a can be further advanced by ozone in the processing gas. Therefore, the etching rate at the first crossing and the etching rate at the second and subsequent crossings can be made substantially the same. Therefore, the proportionality between the number of crossings and the cumulative etching amount can be increased, and these can be in a substantially direct relationship. Therefore, by setting the number of crossings, it is possible to easily control the final etching amount of the silicon-containing material 9a to a desired value.

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

[Etching stop process]
When the number of crossings reaches the set number, the etching process is stopped. As a result, the silicon-containing material 9a of the workpiece 9 can be reliably etched to a desired thickness. The etching can be stopped when the remaining thickness of the silicon-containing film 9a reaches a predetermined value, or the etching can be stopped when the entire silicon-containing film 9a is just removed. The timing for stopping the etching can be easily determined.

[Unloading process]
After the etching process is stopped, the workpiece 9 is unloaded from the unloading port 12 by the roller conveyor 20.

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 same parts as those already described, and the description thereof is omitted.
FIG. 2 shows a second embodiment of the present invention. In this embodiment, the preprocessing nozzle 42 of the preprocessing unit 40 is in contact with the main processing nozzle 33 of the etching processing unit 30. Therefore, the time for shifting from the pretreatment process to the etching process is shorter than in the first embodiment.

The oxidizing reaction component of the processing fluid in the pretreatment process and the oxidizing reaction component of the processing gas in the etching process are not limited to O _3, and may be other oxidizing gases such as NOx.
Furthermore, the processing fluid in the pretreatment process is not limited to gas, and may be an oxidizing liquid such as ozone water or hydrogen peroxide water.
FIG. 3 shows a third embodiment of the present invention. In this embodiment, an ozone water supply unit 45 is used in place of the ozonizer 41 as the processing fluid supply unit. Liquid ozone water is stored in the supply unit 45 as a processing fluid.

In the third embodiment, a preprocessing chamber 50 is provided separately from the processing chamber 10. The pretreatment chamber 50 is disposed on the entry side (right side in FIG. 3) from the treatment chamber 10. A portion of the roller conveyor 20 on the entry side from the processing chamber 10 is disposed in the preprocessing chamber 50. A carry-in port 51 is provided on the upstream wall (right side in FIG. 3) of the pretreatment chamber 50 in the feed direction x. A carry-out port 52 is provided on the wall on the downstream side (left side in FIG. 3) of the pretreatment chamber 50 in the feed direction x. The carry-out port 52 faces the carry-in port 11 of the processing chamber 10.

A spray-type pretreatment nozzle 47 is provided on the upper side of the pretreatment chamber 50. An ozone water supply unit 45 is connected to the spray type pretreatment nozzle 47. The lower part of the spray-type pretreatment nozzle 47 is inserted into the pretreatment chamber 50 and faces the roller conveyor 20 in the pretreatment chamber 50 in the vertical direction. A pretreatment space 49 is defined between the spray type pretreatment nozzle 47 and the roller conveyor 20. The spray port at the tip (lower end) of the spray type pretreatment nozzle 47 faces the pretreatment space 49. A plurality of spray pretreatment nozzles 47 may be arranged in the width direction y orthogonal to the paper surface of FIG.

According to the third embodiment, the workpiece 9 is first carried into the pretreatment chamber 50 from the carry-in port 51 and crosses the pretreatment space 49 in the pretreatment chamber 50 (pretreatment step). At the same time, ozone water from the ozone water supply unit 45 is introduced into the spray pretreatment nozzle 47 and sprayed into the pretreatment space 49. This ozone water comes into contact with the workpiece 9 and an oxidation reaction (formula 1) of the silicon-containing material 9a occurs. Thereafter, the workpiece 9 is unloaded from the unloading port 52 and loaded into the processing chamber 10 from the unloading port 11 (transfer process). During the transfer process, a drying process (not shown) of the workpiece 9 using an air knife or the like is performed. Then, in the processing chamber 10, the etching process of the workpiece 9 is performed in the same manner as in the first embodiment.

FIG. 4 shows a fourth embodiment of the present invention. In this embodiment, the etching processing unit 60 is configured by a so-called direct type plasma processing apparatus. The etching processing unit 60 has first and

second electrodes

61 and 62. A power source (not shown) is connected to the first electrode 61. The second electrode 62 is electrically grounded. A solid dielectric layer (not shown) is provided on the opposing surface of at least one of the

electrodes

61 and 62. When an electric field is applied between the

electrodes

61 and 62, a discharge is generated near atmospheric pressure. A space between the

electrodes

61 and 62 becomes a discharge space 63.

The etching processing unit 60 is provided with an oxygen supply unit 64 in place of the ozonizer 32. Oxygen (O ₂ ) from the oxygen supply unit 64 is mixed with the fluorine-based source gas (CF ₄ + Ar + H ₂ O) from the fluorine-based material supply unit 31 and the addition unit 34. The mixed gas is introduced into the discharge space 63 and turned into plasma. As a result, in the discharge space 63, a fluorine-based reaction component such as HF and an oxidizing reaction component such as ozone and O radical are generated.

The second electrode 62 also serves as a stage, and the workpiece 9 is placed on the upper surface thereof. A moving mechanism 65 is connected to the second electrode / stage 62. Although detailed illustration is omitted, the moving mechanism 65 includes, for example, a linear motion motor, a slide guide, and the like, and reciprocates the second electrode / stage 62 along the feed direction x.

The workpiece 9 is first opposed to the pretreatment nozzle 42 of the pretreatment unit 40. Ozone is sprayed from the pretreatment nozzle 42 onto the workpiece 9. Thereby, the surface portion of the silicon-containing material 9a can be oxidized in advance (pretreatment step).

The workpiece 9 after the pretreatment process is moved onto the stage 62 of the etching processing unit 60 (transfer process). The transfer may be performed manually or using a transfer mechanism such as a robot actuator. Or the said stage 62 may serve as the support part 48 which supports the to-be-processed object 9 in a pre-processing process. That is, first, the workpiece 9 is placed on the stage 62. In the pretreatment step, the stage 62 is opposed to the pretreatment nozzle 42, and as a result, the workpiece 9 is opposed to the pretreatment nozzle 42. Thereafter, the stage 62 and thus the workpiece 9 may be moved to the etching processing unit 60.

In the etching processing unit 60, the workpiece 9 is reciprocally moved across the lower portion of the first electrode 61 by the moving mechanism 65 (etching process step). When the workpiece 9 is positioned in the discharge space 63 so as to face the first electrode 61, each reaction component (HF, COF ₂ , ozone, O radical, etc.) in the processing gas generated in the discharge space 63 is generated. In contact with the workpiece 9, the silicon-containing material 9 a is etched. The discharge space 63 becomes a processing space for performing an etching process. The first electrode 61 constitutes a defining unit that defines the processing space 63 in cooperation with the second electrode / stage 62.

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, by moving the main processing nozzle 33 or the first electrode 61 of the

etching processing units

30 and 60 and the

preprocessing nozzles

42 and 47 of the preprocessing unit 40 by moving the workpiece 9 to be stationary, Switching to the etching process or reciprocation in the etching process may be performed. The moving mechanism may move the main processing nozzle 33 or the first electrode 61 instead of the workpiece 9.

The etching apparatus 1 may include a plurality of

main processing nozzles

33, 33..., And the plurality of

main processing nozzles

33, 33... May be arranged in a line in the x direction. May be arranged in one row. In this case, by moving the object 9 in one direction in the x direction with respect to the

main processing nozzles

33, 33..., The object 9 sequentially traverses the plurality of

processing spaces

39, 39. The movement of the workpiece 9 across one of the

processing spaces

33, 33... Corresponds to one crossing. It is preferable to set the number of main processing nozzles so that the final etching amount of the silicon-containing material 9a becomes a desired value. Of course, the workpiece 9 may be reciprocated in the x direction with respect to the

main processing nozzles

33, 33. A plasma generation unit 35 may be stored in each of the plurality of main processing nozzles 33, and plasma gas generated by one plasma generation unit 35 may be distributed to the plurality of main processing nozzles 33.

In the pretreatment step, the workpiece 9 is placed in the treatment space 39, and only the oxidizing reaction component-containing gas (processing fluid) from the oxidizing reaction component supply unit 32 is blown out from the nozzle 33 to come into contact with the workpiece 9 You may let them. In this case, the processing space 39 also serves as the preprocessing space of the preprocessing unit, the supply unit 32 serves as the processing fluid supply unit 41 of the preprocessing unit, and the nozzle 33 also serves as the preprocessing nozzle. In the subsequent etching step, it is preferable that a processing gas containing a fluorine-based reaction component or an oxidizing reaction component is blown out from the nozzle 33 and brought into contact with the portion 9 to be processed.
A plurality of embodiments may be combined with each other. For example, the ozone water spray nozzle 47 of the third embodiment may be applied as the pretreatment nozzle of the fourth embodiment (FIG. 4).

Examples will be described. In addition, this invention is not limited to a following example.
An apparatus having substantially the same configuration as that of the etching apparatus 1 shown in FIG. 1 was used. The processing target 9 was a glass substrate coated with an amorphous silicon film 9a, and the size thereof was 10 cm × 10 cm. The substrate 9 was subjected to a pretreatment step and then subjected to an etching treatment step. In addition, in the apparatus of Example 1, it replaced with the conveyor 20 as the support part and moving mechanism of the to-be-processed object 9, and used the movement stage.

[Pretreatment process]
An ozone-containing gas (O ₂ + O ₃ ) was introduced from the treatment fluid supply unit 41 to the pretreatment nozzle 42 as a pretreatment treatment fluid, and was blown out from the blowout port 43 a to be brought into contact with the substrate 9. The flow rate of the ozone-containing gas was 1 SLM, and the ozone concentration was 8 to 10 vol%. The width of the outlet 43a (dimension in the direction perpendicular to the paper surface in FIG. 1) was 10 cm. The substrate 9 was transported in the feeding direction x in parallel with the ozone-containing gas spraying. The conveyance speed of the substrate 9 was 4 m / min. The number of times the substrate 9 was passed through the pretreatment space 49 was one.

[Etching process]
Subsequent to the pretreatment step, an etching treatment step was performed. The fluorine-based material gas from the fluorine-based material supply unit 31 is a mixed gas of CF ₄ and Ar, and water (H ₂ O) is added to the mixed gas in the adding unit 34. The flow rate of each gas component was as follows.
CF ₄ : 0.1 SLM
Ar: 1SLM
The dew point of the fluorine-based raw material gas after the addition of water was about 18 ° C. This fluorine-based raw material gas was supplied to the plasma generation unit 35 and turned into plasma under atmospheric pressure. The plasma discharge conditions were as follows.
Thickness of the interelectrode space 36a: 1 mm
Width of electrode 36 (dimension in the direction perpendicular to the plane of FIG. 1): 10 cm
Applied voltage: Vpp = 13kV
Pulse frequency: 40 kHz
The plasma-based fluorine-based gas and the ozone-containing gas (O ₂ + O ₃ ) from the first oxidizing reaction component generation unit 32 were mixed to obtain a processing gas, and this processing gas was blown out from each blowing port 37a. The flow rate of the ozone-containing gas from the first oxidizing reaction component generation unit 32 was 1 SLM, and the ozone concentration was 8 to 10 vol%. The width of the blowout port 37a (dimension in the direction perpendicular to the paper surface in FIG. 1) was 10 cm. The substrate 9 was reciprocated in the feed direction x in parallel with the spraying of the processing gas. The moving speed of the substrate 9 was 4 m / min.

Then, the etching amount corresponding to the number of times the substrate 9 was passed through the processing space 39 (number of crossings) in the etching process was measured. As indicated by the solid line in FIG. 5, the number of crossings and the etching amount were in a substantially proportional relationship. It was confirmed that an etching rate substantially the same as that at the second and subsequent crossings could be obtained even at the first crossing.

[Comparative Example 1]
As a comparative example, the pretreatment process in Example 1 was omitted and only the etching process was performed. The processing conditions for the etching process were exactly the same as in the above example. And the etching amount according to the frequency | count (number of crossings) which passed the board | substrate 9 in the process space 39 in the etching process was measured.

As shown by the broken line in FIG. 5, in Comparative Example 1, the etching rate at the first crossing was lower than the etching rate at the second and subsequent crossings. For this reason, the number of crossings and the etching amount were not directly proportional, and the proportionality was lower than that of Example 1. From the above results, it was shown that it is effective to perform a pretreatment step in advance in controlling the etching amount based on the number of crossings.

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

DESCRIPTION OF SYMBOLS 1 Etching apparatus 9 To-be-processed object 9a Silicon content 10 Processing chamber 11 Carry-in port 12 Carry-out port 20 Roller conveyor (movement mechanism)
21 Shaft 22 Roller 30 Etching processing section 31 Fluorine-based raw material supply section 32 First ozonizer (first oxidizing reaction component generation section)
33 Main processing nozzle (imaging part)
34 Addition unit 35 Plasma generation unit (fluorine-based reaction component generation unit)
36 Electrode 36a Discharge space (interelectrode space)
37 blowing section 37a blowing outlet 39 processing space 40 preprocessing section 41 processing fluid supply section (second oxidizing reaction component generation section)
42 Pretreatment nozzle 43 Blowout part 43a Blowout opening 45 Ozone water supply part (treatment fluid supply part)
47 spray type pretreatment nozzle 48 support part 49 pretreatment space 50 pretreatment chamber 51 carry-in port 52 carry-out port 60 etching treatment part 61 first electrode (definition part)
62 Second electrode / stage 63 Processing space 64 Oxygen supply unit 65 Moving mechanism

Claims

In an etching method for etching a silicon-containing material using a processing gas containing a fluorine-based reaction component and a first oxidizing reaction component in a processing space near atmospheric pressure,
A pretreatment step of bringing a treatment fluid containing a second oxidizing reaction component into contact with an object to be treated containing the silicon-containing material;
After the pretreatment step, the processing gas is supplied to the processing space while moving the object to be processed relative to the processing space so as to cross the processing space, or in the processing space. An etching process for generating the reaction components of the process gas;
An etching method comprising:
2. The etching method according to claim 1, wherein, in the etching process, the etching amount of the silicon-containing material is controlled by adjusting the number of times the object to be processed crosses the processing space.
3. The fluorine-based reaction component is generated by converting the fluorine-based source gas containing a fluorine-containing component and a hydrogen-containing additive component into plasma at a pressure close to atmospheric pressure in the etching process step. The etching method as described in 4. above.
In an etching apparatus for etching a silicon-containing material using a processing gas containing a fluorine-based reaction component and a first oxidizing reaction component in a processing space near atmospheric pressure,
A pretreatment section having a pretreatment nozzle for blowing out a treatment fluid containing a second oxidizing reaction component, and bringing the treatment fluid into contact with an object to be treated containing the silicon-containing material;
An image forming unit that defines the processing space; and a moving mechanism that moves the object to be processed after contact with the processing fluid relative to the image forming unit so as to cross the processing space. An etching processing unit that supplies the processing gas to the processing space or generates the reaction components of the processing gas in the processing space;
An etching apparatus comprising: