JP5182340B2 - Plasma processing apparatus and method - Google Patents

Description

  The present invention includes a thermal plasma process for treating a substrate by irradiating the substrate with thermal plasma, a low-temperature plasma process for treating a substrate by simultaneously irradiating the substrate with plasma by a reactive gas or plasma and a reactive gas flow The present invention relates to a plasma processing apparatus and method.

  Conventionally, semiconductor thin films such as polycrystalline silicon (poly-Si) are widely used for thin film transistors (TFTs) and solar cells. In particular, the poly-Si TFT has a high carrier mobility and can be manufactured on a transparent insulating substrate such as a glass substrate. For example, a pixel circuit such as a liquid crystal display device, a liquid crystal projector, or an organic EL display device can be used. It is widely used as a switching element constituting the circuit or as a circuit element of a liquid crystal driving driver.

  As a method for manufacturing a high-performance TFT on a glass substrate, there is a manufacturing method generally called “high temperature process”. Among TFT manufacturing processes, a process using a high temperature with a maximum temperature of about 1000 ° C. is generally called a “high temperature process”. Features of the high-temperature process are that a relatively good quality polycrystalline silicon can be formed by solid phase growth of silicon, a good quality gate insulating layer can be obtained by thermal oxidation of silicon, and a clean polycrystalline. This is the point that an interface between silicon and the gate insulating layer can be formed. Due to these characteristics, a high-performance TFT having high mobility and high reliability can be stably manufactured in a high-temperature process.

  On the other hand, since the high temperature process is a process of crystallizing a silicon film by solid phase growth, a long-time heat treatment of about 48 hours is required at a temperature of about 600 ° C. This is a very long process, and in order to increase the process throughput, a large number of heat treatment furnaces are inevitably required, and it is difficult to reduce the cost. In addition, quartz glass has to be used as an insulating substrate with high heat resistance, so the cost of the substrate is high and it is said that it is not suitable for large area.

  On the other hand, a technique for lowering the maximum temperature in the process and manufacturing a poly-Si TFT on an inexpensive large-area glass substrate is a technique called “low temperature process”. Among TFT manufacturing processes, a process for manufacturing poly-Si TFTs on a heat-resistant glass substrate that is relatively inexpensive in a temperature environment where the maximum temperature is approximately 600 ° C. or lower is generally called a “low-temperature process”. In a low temperature process, a laser crystallization technique for crystallizing a silicon film using a pulse laser having an extremely short oscillation time is widely used. Laser crystallization is a technique that utilizes the property of crystallizing in the process of solidifying instantaneously by irradiating a silicon thin film on a substrate with high-power pulsed laser light.

  However, this laser crystallization technique has some major problems. One is a large amount of trap levels localized inside the polysilicon film formed by the laser crystallization technique. Due to the presence of the trap level, carriers that are supposed to move in the active layer by the application of voltage are trapped and cannot contribute to electrical conduction, which has adverse effects such as a decrease in TFT mobility and an increase in threshold voltage. Further, there is a problem that the size of the glass substrate is limited due to the limitation of the laser output. In order to improve the throughput of the laser crystallization process, it is necessary to increase the area that can be crystallized at one time. However, since the current laser output is limited, when this crystallization technique is adopted for a large substrate such as the seventh generation (1800 mm × 2100 mm), it takes a long time to crystallize one substrate.

  Laser crystallization technology generally uses a laser shaped in a line, and crystallization is performed by scanning this laser. This line beam is shorter than the width of the substrate because of limited laser output, and it is necessary to scan the laser several times in order to crystallize the entire surface of the substrate. As a result, a line beam seam area is generated in the substrate, and an area that is scanned twice is formed. This region is significantly different in crystallinity from the region crystallized by one scan. For this reason, the element characteristics of the two are greatly different, which causes a large variation in devices. Finally, since the laser crystallization apparatus has a complicated apparatus configuration and a high cost of consumable parts, there are problems that the apparatus cost and running cost are high. As a result, a TFT using a polysilicon film crystallized by a laser crystallization apparatus becomes an element with a high manufacturing cost.

  In order to overcome the problems such as the limitation of the substrate size and the high apparatus cost, a crystallization technique called “thermal plasma jet crystallization method” has been studied (for example, see Non-Patent Document 1). The technology is briefly described below. When a tungsten (W) cathode and a water-cooled copper (Cu) anode are opposed to each other and a DC voltage is applied, an arc discharge occurs between the two electrodes. By flowing argon gas between these electrodes under atmospheric pressure, thermal plasma is ejected from the ejection holes vacated in the copper anode. Thermal plasma is thermal equilibrium plasma, which is an ultra-high temperature heat source having substantially the same temperature of ions, electrons, neutral atoms, etc., and the temperature of which is about 10,000K. Therefore, the thermal plasma can easily heat the object to be heated to a high temperature, and the substrate on which the a-Si film is deposited scans the front surface of the ultra-high temperature thermal plasma at a high speed, thereby crystallizing the a-Si film. Can be

  Thus, since the apparatus configuration is very simple and the crystallization process is performed under atmospheric pressure, it is not necessary to cover the apparatus with an expensive member such as a chamber, and the apparatus cost can be expected to be extremely low. The utilities required for crystallization are argon gas, electric power, and cooling water, which is a crystallization technique with low running costs.

  FIG. 7 is a schematic diagram for explaining a semiconductor film crystallization method using this thermal plasma.

  In FIG. 1, a thermal plasma generator 31 includes a cathode 32 and an anode 33 that is disposed to face the cathode 32 with a predetermined distance therebetween. The cathode 32 is made of a conductor such as tungsten. The anode 33 is made of a conductor such as copper, for example. Further, the anode 33 is formed in a hollow shape, and is configured to be cooled through water through the hollow portion. The anode 33 is provided with an ejection hole (nozzle) 34. When a direct current (DC) voltage is applied between the cathode 32 and the anode 33, an arc discharge is generated between the two electrodes. In this state, by flowing a gas such as argon gas between the cathode 32 and the anode 33 under atmospheric pressure, the thermal plasma 35 can be ejected from the ejection hole 34. Here, the “thermal plasma” is a thermal equilibrium plasma, which is an ultra-high temperature heat source having substantially the same temperature of ions, electrons, neutral atoms, etc., and having a temperature of about 10,000K.

  Such thermal plasma can be used for heat treatment for crystallization of a semiconductor film. Specifically, a semiconductor film 37 (for example, an amorphous silicon film) is formed on the substrate 36, and thermal plasma (thermal plasma jet) 35 is applied to the semiconductor film 37. At this time, the thermal plasma 35 is applied to the semiconductor film 37 while relatively moving along a first axis (left and right direction in the illustrated example) parallel to the surface of the semiconductor film 37. That is, the thermal plasma 35 is applied to the semiconductor film 37 while scanning in the first axis direction. Here, “relatively move” means that the semiconductor film 37 (and the substrate 23 supporting it) and the thermal plasma 35 are relatively moved, and only one of them is moved and both are moved together. Any of the cases are included. By such scanning of the thermal plasma 35, the semiconductor film 37 is heated by the high temperature of the thermal plasma 35 to obtain a crystallized semiconductor film 38 (polysilicon film in this example) (for example, see Patent Document 1). ).

  FIG. 8 is a conceptual diagram showing the relationship between the depth from the outermost surface and the temperature. As shown in FIG. 8, only the vicinity of the surface can be processed at a high temperature by moving the thermal plasma 35 at a high speed. After the thermal plasma 35 passes, the heated region is quickly cooled, so that the vicinity of the surface becomes high temperature for a very short time.

  Such a thermal plasma is generally generated in a dotted region. The thermal plasma is maintained by thermionic emission from the cathode 32, and thermionic emission becomes more active at a position where the plasma density is high. Therefore, positive feedback is applied, and the plasma density becomes higher. That is, arc discharge is concentrated on one point of the cathode, and thermal plasma is generated in a dotted region.

  If you want to process a flat substrate uniformly, such as when crystallizing a semiconductor film, it is necessary to scan a dotted thermal plasma over the entire substrate. In order to construct a process that can be processed, it is effective to widen the thermal plasma irradiation area. For this reason, techniques for generating thermal plasma over a large area have been studied for a long time.

  For example, a method for widening a plasma jet by simultaneously jetting a widening gas for widening the plasma jet from two locations in a direction intersecting the central axis of the outer nozzle onto a plasma jet ejected from the outer nozzle of the plasma torch Is disclosed (for example, see Patent Document 2). Alternatively, a plasma nozzle characterized in that the mouth portion of the nozzle passage is inclined at a predetermined angle with respect to the axis of the nozzle passage, and a casing constituting the nozzle passage, or a part of the casing, A method is disclosed in which a plasma nozzle is passed and moved along a workpiece by rotating it around the longitudinal axis at high speed (see, for example, Patent Document 3). Further, there is disclosed one provided with a rotating head having at least one eccentrically arranged plasma nozzle (see, for example, Patent Document 4).

  It is not intended to process a large area in a short time, but as a welding method using thermal plasma, a strip electrode is used and the width direction is arranged to be the weld line direction and welding is performed. A high-speed gas shielded arc welding method is disclosed (see, for example, Patent Document 5).

  In addition, an inductively coupled plasma torch having a linear elongated shape using a flat rectangular parallelepiped insulator material is disclosed (for example, see Patent Document 6).

  In addition, a method of generating a long and narrow linear plasma using a long electrode has been disclosed (for example, see Patent Document 7). Although described as generating heat plasma, it generates low-temperature plasma and is not suitable for heat treatment. If thermal plasma is generated, it is assumed that it is difficult to generate uniform thermal plasma in the longitudinal direction because arc discharge is concentrated in one place because of the capacitive coupling type using electrodes. On the other hand, the low temperature plasma processing apparatus is an apparatus capable of performing plasma processing such as etching and film formation by converting an etching gas or a gas for CVD (Chemical Vapor Deposition) into plasma.

  In addition, in the conventional cylindrical ICP torch, a plasma gas and a sheath gas that are supplied along the wall surface of a member constituting the cylindrical chamber have been disclosed. Is generally cylindrical (see, for example, Non-Patent Document 2: FIG. 8).

JP 2008-53634 A Japanese Patent Laid-Open No. 08-118027 JP 2001-68298 A Special Table 2002-500818 Japanese Patent Laid-Open No. 04-284974 Special table 2009-545165 gazette JP 2007-287454 A

S. Higashi, H .; Kaku, T .; Okada, H .; Murakami and S.M. Miyazaki, Jpn. J. et al. Appl. Phys. 45, 5B (2006) pp. 4313-4320 Jun Takeuchi, Tomohisa Okada, Toyonobu Yoshida, Kazuo Akashi, Journal of the Japan Institute of Metals 52, 7 (1988) pp. 711-718

  However, conventional techniques for generating a large area of thermal plasma have not been effective for applications in which the vicinity of the surface of a substrate is treated at a high temperature for a very short time, such as crystallization of a semiconductor.

  In the technology for generating thermal plasma in a large area described in Patent Document 2 shown in the conventional example, although the width is widened, the temperature distribution in the widened region is 100 ° C. or more and is uniform. Realization of heat treatment is impossible.

  Further, in the techniques described in Patent Documents 3 and 4 shown in the conventional example, the thermal plasma is generated in a large area, and the heat plasma is essentially oscillated. Since the time is shorter than when scanning without rotating, the time for processing a large area is not particularly shortened. Further, for uniform processing, it is necessary to make the rotation speed sufficiently higher than the scanning speed, and it is inevitable that the nozzle configuration becomes complicated.

  Moreover, the technique described in Patent Document 5 shown in the conventional example is a welding technique and is not a configuration for uniformly processing a large area. Even if this is applied to a large area processing application, in this configuration, since a point-like arc vibrates along the strip electrode, plasma is generated uniformly when time averaged, but instantaneously non-uniform plasma is generated. Has occurred. Therefore, it cannot be applied to large area uniform processing.

  Further, the technique described in Patent Document 6 shown in the conventional example is an inductively coupled high-frequency plasma torch, unlike the technique using DC arc discharge disclosed in Non-Patent Document 1 and Patent Document 1. It is a feature. Since it is an electrodeless discharge, it has the advantages of excellent thermal plasma stability (small time change) and less contamination (contamination) of electrode material into the substrate.

  In an inductively coupled plasma torch, in order to protect the insulator material from high-temperature plasma, a method is generally adopted in which the insulator material is made into a double tube configuration and a coolant is passed therebetween. However, in the technique described in Patent Document 6 shown in the conventional example, since the insulator material has a flat rectangular parallelepiped shape, a refrigerant having a sufficient flow rate can be obtained simply by adopting a double tube configuration. Can't flow. This is because the insulator material is generally inferior in mechanical strength to metal, and if the insulator material is too long in the longitudinal direction, the internal pressure of the double pipe cannot be increased. For this reason, there is a limit to uniformly processing a large area.

  Even if it is assumed that there is no problem of cooling of the insulator material, in the technique described in Patent Document 6 shown in the conventional example, the high-temperature plasma formed in the internal space of the insulator material is from the lowermost part. Since only a small part of the jetting is directly applied to the base material, there is a problem that power efficiency is poor. Further, in the internal space of the insulator material, since the plasma density near the center is high, there is a problem that the plasma becomes non-uniform in the longitudinal direction and the substrate cannot be processed uniformly.

  Even in the case of dot-like thermal plasma, if the diameter is large, the number of scans during large area processing can be reduced, so that it can be processed in a short time depending on the application. However, if the diameter of the thermal plasma is large, the time for the thermal plasma to pass over the substrate during scanning becomes substantially longer, so that only the vicinity of the surface of the substrate cannot be treated at a high temperature for a very short time. Even a considerably deep region of the material becomes high temperature, which may cause defects such as cracking of the glass substrate and peeling of the film.

  Further, in the technique described in Non-Patent Document 2 shown in the conventional example, in the cylindrical ICP torch widely used in the past, the shape of the gas inlet is cylindrical as a whole, so that it has a uniform large area. Not suitable for processing.

  The present invention has been made in view of such a problem. When the high-temperature heat treatment is performed uniformly in the vicinity of the surface of the base material for a very short time, or the base material is irradiated with plasma by the reactive gas or plasma and the reactive gas flow at the same time. Therefore, it is an object of the present invention to provide a plasma processing apparatus and method capable of processing the entire desired region of the base material in a short time when the base material is subjected to low temperature plasma processing.

A plasma processing apparatus according to a first invention of the present application includes a cylindrical chamber having a slit-shaped opening, a gas inlet for supplying gas into the chamber, a coil for generating a high-frequency electromagnetic field in the chamber, In a plasma processing apparatus having a high-frequency power source that supplies high-frequency power to a coil, and a substrate mounting table that holds the substrate and is disposed to face the opening,
The cylindrical chamber is composed of a long and conductive casing and a long dielectric cylinder provided inside the casing, and the longitudinal direction of the cylindrical chamber and the opening is arranged parallel to the longitudinal direction, perpendicular orientation relative to the longitudinal direction of the opening, provided with a movement mechanism that allows relative movement between the chamber and the substrate mounting table, the gas inlet , the housing from between the dielectric tube, characterized in that it is configured to introduce the housing and the gas along the surface of the dielectric tube.

  With such a configuration, when the high temperature heat treatment is performed uniformly in the vicinity of the surface of the base material for a very short time, or the base material is subjected to low temperature plasma treatment by irradiating the base material with plasma or plasma and a reactive gas flow at the same time. In this case, it is possible to realize a plasma processing apparatus that can process the entire desired region of the substrate in a short time.

  In the plasma processing apparatus of the first invention of the present application, it is preferable that the plasma processing apparatus includes a gas manifold that is arranged in parallel to the longitudinal direction of the cylindrical chamber and communicates with the gas inlet.

  With such a configuration, plasma processing with excellent longitudinal uniformity can be realized.

In this case, it is more preferable that the gas manifold is formed by a groove provided in the housing .

  With such a configuration, a simple structure can be realized.

Preferably, the gas supply hole that communicates the gas manifold and the gas introduction port is formed by a groove provided in the housing .

  With such a configuration, a simpler structure can be realized.

  More preferably, the depth of the groove constituting the gas supply hole is preferably smaller than the depth of the groove constituting the gas manifold.

  With such a configuration, it is possible to realize a plasma process that is further excellent in uniformity in the longitudinal direction.

  In the plasma processing apparatus of the first invention of the present application, preferably, the coil is a solenoid coil, and the extending direction of the coil and the longitudinal direction of the opening are preferably arranged in parallel.

  With such a configuration, plasma processing with excellent uniformity in the longitudinal direction of the opening can be realized.

  In this case, more preferably, the space inside the chamber is U-shaped in a cross-sectional shape obtained by cutting the chamber along a plane perpendicular to the extending direction of the coil.

  With such a configuration, it is possible to realize a plasma process that is further excellent in uniformity in the longitudinal direction.

  Preferably, the outside of the U-shaped space inside the chamber is configured by a metal cylinder, the inside of the U-shaped space inside the chamber is configured by a dielectric cylinder, and the dielectric cylinder includes It is desirable that a coil be provided.

  With such a configuration, it is possible to realize plasma processing with excellent reliability and excellent uniformity in the longitudinal direction.

In the plasma processing method of the second invention of the present application, gas is supplied into a cylindrical chamber composed of a long and conductive casing and a long dielectric cylinder provided inside the casing. In the plasma processing method for generating a high-frequency electromagnetic field in the chamber by ejecting gas from the slit-shaped opening formed in the chamber toward the base material and supplying high-frequency power to the coil, in treating the surface of the substrate while relatively moving the said substrate and said chamber perpendicular orientation relative to the longitudinal direction of the opening, from between the dielectric tube and the housing, wherein the housing A gas is supplied into the cylindrical chamber along the surface of the body and the dielectric cylinder .

  With such a configuration, when the high temperature heat treatment is performed uniformly in the vicinity of the surface of the base material for a very short time, or the base material is subjected to low temperature plasma treatment by irradiating the base material with plasma or plasma and a reactive gas flow at the same time. At this time, it is possible to realize a plasma processing method capable of processing the entire desired region of the base material in a short time.

  According to the present invention, when a high temperature heat treatment is performed uniformly in the vicinity of the surface of the base material for a very short time, or the base material is subjected to low temperature plasma treatment by simultaneously irradiating the base material with plasma or plasma and a reactive gas flow. At this time, it is possible to realize plasma processing that can process the entire desired region of the substrate in a short time.

Sectional drawing which shows the structure of the plasma processing apparatus in Embodiment 1 of this invention The perspective view which shows the structure of the plasma processing apparatus in Embodiment 1 of this invention. The perspective view which shows the structure of the plasma processing apparatus in Embodiment 1 of this invention. Sectional drawing which shows the structure of the plasma processing apparatus in Embodiment 2 of this invention. The perspective view which shows the structure of the plasma processing apparatus in Embodiment 2 of this invention. The perspective view which shows the structure of the plasma processing apparatus in Embodiment 2 of this invention. Schematic diagram for explaining a conventional method for crystallizing a semiconductor film using thermal plasma Conceptual diagram showing the relationship between the depth from the outermost surface and the temperature in the conventional example

  Hereinafter, a plasma processing apparatus according to an embodiment of the present invention will be described with reference to the drawings.

(Embodiment 1)
Hereinafter, Embodiment 1 of the present invention will be described with reference to FIGS.

  FIG. 1A shows the configuration of the plasma processing apparatus according to Embodiment 1 of the present invention, and is a cross-sectional view taken along a plane perpendicular to the longitudinal direction of an inductively coupled plasma torch unit. FIG. 1B is a cross-sectional view taken along broken lines A to A ′ in FIG. 1A, and includes a central axis of the solenoid coil and a cross-sectional view taken along a plane perpendicular to the substrate.

  1A is a cross-sectional view taken along broken lines B to B ′ in FIG. FIG. 2 is an assembly configuration diagram of the inductively coupled plasma torch unit shown in FIG. 1, in which perspective views of respective components are arranged. FIG. 3 is a perspective view of the lid constituting the inductively coupled plasma torch unit as viewed from below.

  1 to 3, the base material 2 is placed on the base material placing table 1. In the inductively coupled plasma torch unit T, a helical conductor rod 3 forming a solenoid coil is disposed inside the quartz tube 4 as a dielectric cylinder so as to penetrate the quartz tube 4. Around the quartz tube 4, a brass block 5 serving as a housing for providing a wall surface of the cylindrical chamber is disposed, and the upper side of the quartz tube 4 is in contact with a brass lid 6. The space 7 inside the cylindrical chamber is a cylindrical, long and thin U-shaped space surrounded by the quartz tube 4, the brass block 5, the lid 6, and the brass block 17. That is, of the cross-sectional shape obtained by cutting the cylindrical chamber along a plane perpendicular to the extending direction of the conductor rod 3, the space inside the cylindrical chamber is U-shaped. The extending direction of the conductor rod 3 is the direction of the central axis of the solenoid coil formed by the conductor rod 3 (the left-right direction in FIG. 1B), and means the direction in which the coil extends.

  Below the lid 6, a groove to be a plasma gas manifold 8, a groove to be a plasma gas supply hole 9, a groove to be a sheath gas manifold 10, and a groove to be a sheath gas supply hole 11 are formed. Further, a shield gas nozzle 13 is disposed in a portion close to the substrate mounting table 1, and a shield gas manifold 14 is provided therein. In this way, three types of gas introduction are prepared, and the gas type, gas flow rate, and the like are appropriately adjusted by dividing into plasma gas suitable for plasma generation and sheath gas protecting the inner wall surface of the brass block 5. In addition to enabling stable plasma processing, it is possible to reduce the contamination of the plasma irradiation surface with gases that are unnecessary or have an adverse effect on the processing, such as oxygen and carbon dioxide in the air by supplying a separate shielding gas. It becomes.

  The inside of the quartz tube 4 in which the conductor rod 3 is disposed is immersed in water as an insulating fluid, and the conductor rod 3 is cooled by flowing water as a refrigerant. The brass block 5 and the lid 6 are provided with a cooling water pipe 15 penetrating them. These water passages (refrigerant flow passages) communicate with a cooling water manifold 22 as a refrigerant manifold formed by a space between the resin case 18 provided outside the brass block 17 and the brass block 17. The resin case 18 is provided with one coolant inlet / outlet 24 as a refrigerant inlet / outlet, and the water cooling piping to the inductively coupled torch unit T is very simple. A small torch can be constructed.

  The conductor rod 3 is connected to the copper block 19 through a high frequency introducing terminal hole 26 and a ground terminal hole 27 provided in the resin case 18, and is connected to a high frequency matching circuit (not shown) through the copper plate 20.

  A rectangular slit-shaped plasma nozzle 12 (which may be referred to as an “opening”) is provided, and the substrate mounting table 1 (or the substrate 2 on the substrate mounting table 1) is a plasma nozzle. 12 is arranged to face. In this state, high-frequency power is applied to the conductor rod 3 that forms a solenoid coil from a high-frequency power source (not shown) while gas is ejected from the plasma outlet 12 toward the base material 2 while gas is supplied into the cylindrical chamber. By supplying, plasma is generated in the cylindrical chamber, and the thin film 16 on the base material 2 can be plasma-treated by irradiating the base material 2 with the plasma from the plasma outlet 12.

  This configuration is characterized in that the longitudinal direction of the cylindrical chamber, the extending direction of the coil, and the longitudinal direction of the opening 12 are all arranged in parallel, and is perpendicular to the longitudinal direction of the opening 12. The substrate 2 is processed by moving the chamber and the substrate mounting table 1 relative to each other. That is, the inductively coupled plasma torch unit T or the substrate mounting table 1 is moved in the left-right direction in FIG. 1A and in the direction perpendicular to the paper surface in FIG.

  Next, the gas supply structure will be described. The plasma gas supply pipe 41 and the sheath gas supply pipe 42 are provided on the lid 6 and communicate with the plasma gas manifold 8 and the sheath gas manifold 10 through a through hole inside the lid 6.

  As shown in FIG. 3, grooves serving as manifolds 8 and 10 and gas supply holes 9 and 11 are formed on the lower surface of the lid 6. The grooves that form the manifolds 8 and 10 are deep and long dug in parallel with the longitudinal direction of the cylindrical chamber, and function as a gas reservoir. The grooves to be the gas supply holes 9 and 11 are shallow and are dug short in parallel with the longitudinal direction of the cylindrical chamber, and the number thereof is large. In other words, the depth of the grooves constituting the gas supply holes 9 and 11 is smaller than the depth of the grooves constituting the gas manifolds 8 and 10. From a slight gap between the convex portion of the lid 6 and the quartz tube 4, two members (the convex portion of the lid 6 and the quartz tube 4) are directed downward from the torch unit T toward the base material 2. It is the structure which oozes out along the surface of two members from between.

  Similarly, from a slight gap between the convex portion of the lid 6 and the brass block 5, the sheath gas is directed downward, that is, in the direction from the torch unit T to the base material 2, with the two members (the convex portion of the lid 6 and the brass block It is the structure which oozes out along the surface of two members from between 5). If the portion where the gas leaks into the cylindrical chamber is called a gas inlet, the gas inlet is provided in parallel to the longitudinal direction of the opening 12 and is provided on the surface facing the opening 12. It has a configuration. With such a configuration, the gas flow in the cylindrical chamber and the gas flow from the gas outlet toward the substrate mounting table 1 are both smooth and easily stratified, thereby enabling stable plasma processing. . On the other hand, the shielding gas is ejected between the opening 12 and the substrate 2 from a large number of holes communicating with the shielding gas manifold 14 or a single groove.

  At this time, by devising the direction of the hole or the single groove, the direction of gas ejection can be directed to the opening 12 or the surface of the substrate 2, depending on the type of treatment. What is necessary is just to select suitably.

  Further, in this configuration, since the length of the plasma injection port 12 in the longitudinal direction is equal to or larger than the width of the base material 2, one-time scanning (relative movement of the torch unit T and the base material mounting table 1 is performed). Thus, the entire thin film 16 near the surface of the substrate 2 can be heat-treated.

In such a plasma processing apparatus, Ar or Ar + H ₂ gas from the gas ports in the tubular chamber, while supplying N ₂ gas from the shield gas port, a gas toward the plasma jetting port 12 to the substrate 2 spouting Then, by supplying high frequency power of 13.56 MHz from a high frequency power source (not shown) to the conductor rod 3 forming the solenoid coil, plasma is generated in the cylindrical chamber, and the plasma is supplied from the plasma outlet 12 to the base material. By irradiating 2 and scanning, heat treatment such as crystallization of the semiconductor film can be performed.

  As described above, the direction of the central axis of the solenoid coil, the longitudinal direction of the plasma ejection port 12, and the base material mounting table 1 are arranged in parallel with each other in a direction perpendicular to the longitudinal direction of the plasma ejection port 12, Since the cylindrical chamber and the substrate mounting table 1 are relatively moved, it is possible to configure the length of the plasma to be generated and the processing length of the substrate 2 to be substantially equal.

  Further, the width of the cross section obtained by cutting the cylindrical chamber along a plane perpendicular to the central axis (the width of the chamber internal space 7 in FIG. 1B) is the width of the plasma outlet 12 (the gap in FIG. 1B). It is sufficient if it is slightly larger than That is, the volume of plasma to be generated can be made extremely small compared to the conventional one. As a result, power efficiency is dramatically increased.

  Further, in the internal space of the cylindrical chamber, relatively uniform plasma can be generated in the direction of the central axis, so that the plasma becomes uniform in the longitudinal direction and the substrate can be processed uniformly.

(Embodiment 2)
Hereinafter, a second embodiment of the present invention will be described with reference to FIGS.

  FIG. 4A shows the configuration of the plasma processing apparatus according to Embodiment 2 of the present invention, and is a cross-sectional view taken along a plane perpendicular to the longitudinal direction of the inductively coupled plasma torch unit. 4B is a cross-sectional view taken along broken lines A to A ′ in FIG. 4A, and is a cross-sectional view taken along a plane that includes the central axis of the solenoid coil and is perpendicular to the base material.

  4A is a cross-sectional view taken along broken lines B to B ′ in FIG. FIG. 5 is an assembly configuration diagram of the inductively coupled plasma torch unit shown in FIG. 4, in which perspective views of respective components are arranged. FIG. 6 is a perspective view of the lid constituting the inductively coupled plasma torch unit as viewed from below.

  In the second embodiment of the present invention, only the shapes of the quartz tube 4 and the lid 6 are different from those of the first embodiment, and therefore other explanations are omitted.

  The quartz tube 4 is a cylinder having a uniform outer diameter, excluding protruding portions for positioning and sealing (parts of which have a larger outer diameter). It is superior to Embodiment 1 of the invention. In order to make the gas flow laminar by filling the space above the quartz tube 4, the lower part of the lid 6 is greatly convex downward. And it is shape | molded in circular arc shape so that the front-end | tip of a convex part may follow the quartz tube 4. As shown in FIG. Further, since the water-cooled pipe 15 can be formed on the convex portion, more effective water cooling than in the first embodiment is possible.

  The plasma gas supply pipe 41 and the sheath gas supply pipe 42 are provided on the lid 6 and communicate with the plasma gas manifold 8 and the sheath gas manifold 10 through a through hole inside the lid 6. As shown in FIG. 6, grooves serving as manifolds 8 and 10 and gas supply holes 9 and 11 are formed on the lower surface of the lid 6. The grooves that form the manifolds 8 and 10 are deep and long dug in parallel with the longitudinal direction of the cylindrical chamber, and function as a gas reservoir. The groove to be the gas supply hole 9 is shallow and is dug long in parallel with the longitudinal direction of the cylindrical chamber, and the number thereof is one. The grooves serving as the gas supply holes 11 are shallow and are dug short in parallel with the longitudinal direction of the cylindrical chamber, and the number thereof is large. In other words, the depth of the grooves constituting the gas supply holes 9 and 11 is smaller than the depth of the grooves constituting the gas manifolds 8 and 10.

  A major difference from the first embodiment is that the groove to be the gas supply hole 9 is dug long in the longitudinal direction. Even in the configuration as in the second embodiment, a large number of shallow grooves dug in the longitudinal direction can be used. Conversely, in the configuration as in the first embodiment, the trench is dug out in the longitudinal direction. It is also possible to use a single shallow groove.

  In this configuration, the plasma gas oozes out downward, that is, in the direction from the torch unit T toward the base material 2 from a slight gap (shallow groove) between the convex portion of the lid 6 and the quartz tube 4. . Similarly, from a slight gap between the convex portion of the lid 6 and the brass block 5, the plasma gas oozes downward, that is, in the direction from the torch unit T to the base material 2.

  The plasma processing apparatus and method described above merely exemplify typical examples of the scope of application of the present invention.

  The various configurations of the present invention enable high-temperature treatment of the vicinity of the surface of the substrate 2, but can be applied to the crystallization of the semiconductor film for TFT and the modification of the semiconductor film for solar cell described in detail in the conventional example. Of course, various surfaces such as cleaning and reducing degassing of the protective layer of plasma display panels, flattening and reducing degassing of dielectric layers composed of aggregates of silica fine particles, reflow of various electronic devices, etc. Applicable to processing. Moreover, as a manufacturing method of a solar cell, it can apply also to the method of apply | coating the powder obtained by grind | pulverizing a silicon ingot on a base material, and irradiating this with a plasma and fuse | melting it, and obtaining a polycrystalline silicon film.

  Further, the inductively coupled plasma torch unit T may be scanned with respect to the fixed substrate mounting table 1, but the substrate mounting table 1 is scanned with respect to the fixed inductively coupled plasma torch unit T. May be.

  The helical coil may be a multiple helical shape as disclosed in JP-A-8-83696. With such a configuration, the inductance of the coil can be reduced and the power efficiency can be improved. This is particularly effective when the width of the base material 2 to be treated is large, that is, when the inductively coupled plasma torch unit or the coil is elongated in the longitudinal direction.

  Further, a plurality of point-like gas outlets may be arranged, or may be linear.

  Moreover, although the structure which used the brass as a metal of a component material was illustrated, the part which corresponds to the inner wall of a cylindrical chamber among the components which consist of a metal material is coated with an insulator material, and mixing of the metal material to plasma is carried out. It is possible to prevent arc discharge while preventing it.

  It is also possible to use an ignition source in order to facilitate plasma ignition. As an ignition source, an ignition spark device used for a gas water heater or the like can be used.

  In the description, the term “thermal plasma” is used for simplicity. However, it is difficult to distinguish between thermal plasma and low temperature plasma. For example, Tanaka Yasunori “Non-equilibrium in thermal plasma” plasma nucleus Journal of Fusion Society, Vol. 82, no. 8 (2006) p. As described in 479-483, it is also difficult to classify plasma types based on thermal equilibrium alone. The present invention has an object of heat-treating a substrate, and can be applied to a technique for irradiating high-temperature plasma without being bound by terms such as thermal plasma, thermal equilibrium plasma, and high-temperature plasma.

In addition, the case where high-temperature heat treatment is performed in the vicinity of the surface of the base material uniformly for a very short time is illustrated in detail. The present invention can also be applied. By mixing the reaction gas with the plasma gas or the sheath gas, the plasma by the reaction gas is irradiated onto the substrate, and etching or CVD can be realized. Alternatively, by using a rare gas or a gas obtained by adding a small amount of H ₂ gas to the rare gas as the sheath gas, a gas containing a reactive gas is supplied as a shielding gas, so that the plasma and the reactive gas flow can be simultaneously formed on the substrate. Etching and CVD can also be realized.

  When a gas containing argon as a main component is used as the plasma gas or the sheath gas, thermal plasma is generated as exemplified in detail in the embodiments. On the other hand, when a gas containing helium as a main component is used as a plasma gas or a sheath gas, a relatively low temperature plasma can be generated. By such a method, processing such as etching and film formation can be performed without heating the substrate too much.

Examples of the reactive gas used for etching include a halogen-containing gas such as C _x F _y (x and y are natural numbers), SF _{6, and the} like, and silicon and silicon compounds can be etched. If O ₂ is used as the reaction gas, it is possible to remove organic substances, resist ashing, and the like. The reactive gas used for CVD includes monosilane, disilane, and the like, and silicon or silicon compound can be formed. Alternatively, a silicon oxide film can be formed by using a mixed gas of O ₂ and an organic gas containing silicon typified by TEOS (Tetraethoxysilane).

  In addition, various low-temperature plasma treatments such as surface treatment for modifying water repellency and hydrophilicity are possible. Compared to the prior art (for example, described in Patent Document 7), since it is an inductive coupling type, even if a high power density per unit volume is applied, it is difficult to shift to arc discharge, so a higher density plasma is generated. As a result, a high reaction rate can be obtained, and the entire desired region to be treated of the substrate can be processed in a short time.

  As described above, the present invention can be applied to the crystallization of the TFT semiconductor film and the modification of the semiconductor film for the solar cell, as well as cleaning the protective layer of the plasma display panel, reducing the degassing, In various surface treatments such as surface flattening of dielectric layers consisting of aggregates, reduction of degassing, reflow of various electronic devices, etc. This invention is useful for processing the entire desired region to be processed in a short time. Further, the present invention is useful for processing the entire desired region of the substrate in a short time in low temperature plasma processing such as etching, film formation, and surface modification in manufacturing various electronic devices.

DESCRIPTION OF SYMBOLS 1 Base material mounting base 2 Base material T Inductive coupling type plasma torch unit 3 Conductor rod 4 Quartz tube 5 Brass block 6 Lid 7 Chamber internal space 8 Plasma gas manifold 9 Plasma gas supply hole 10 Sheath gas manifold 11 Sheath gas supply hole 12 Plasma jet Outlet 13 Shield gas nozzle 14 Shield gas manifold 15 Cooling water piping 16 Thin film 17 Brass block 18 Resin case 19 Copper block 20 Copper plate 22 Cooling water manifold 41 Plasma gas supply piping

Claims (9)

A cylindrical chamber having a slit-like opening, a gas inlet for supplying gas into the chamber, a coil for generating a high-frequency electromagnetic field in the chamber, a high-frequency power source for supplying high-frequency power to the coil, In a plasma processing apparatus having a substrate and a substrate mounting table disposed opposite to the opening,
The cylindrical chamber is composed of a long and conductive casing, and a long dielectric cylinder provided inside the casing, and
The longitudinal direction of the cylindrical chamber and the longitudinal direction of the opening are arranged in parallel,
A moving mechanism that allows the chamber and the substrate mounting table to move relatively in a direction perpendicular to the longitudinal direction of the opening;
Said gas inlet, said from between the housing and the dielectric tube, the plasma processing apparatus, wherein said the housing along the surface of the dielectric tube is configured to introduce gas. The plasma processing apparatus according to claim 1, further comprising a gas manifold arranged in parallel to a longitudinal direction of the cylindrical chamber and communicating with the gas inlet. The plasma processing apparatus according to claim 2, wherein the gas manifold includes a groove provided in the housing . The plasma processing apparatus according to claim 2, wherein a gas supply hole that communicates the gas manifold and the gas introduction port includes a groove provided in the housing . The plasma processing apparatus according to claim 4, wherein a depth of a groove constituting the gas supply hole is smaller than a depth of a groove constituting the gas manifold. The plasma processing apparatus according to claim 1, wherein the coil is a solenoid coil, and the extending direction of the coil and the longitudinal direction of the opening are arranged in parallel. The plasma processing apparatus according to claim 6, wherein a space inside the chamber is U-shaped in a cross-sectional shape obtained by cutting the chamber along a plane perpendicular to the extending direction of the coil. The outside of the U-shaped space inside the chamber is configured by a metal cylinder, the inside of the U-shaped space inside the chamber is configured by a dielectric cylinder, and the coil is provided in the dielectric cylinder. The plasma processing apparatus according to claim 7. A slit-like opening formed in the chamber while supplying gas into a cylindrical chamber composed of a long, conductive casing and a long dielectric cylinder provided inside the casing. In the plasma processing method for generating a high-frequency electromagnetic field in the chamber by ejecting gas from the portion toward the substrate and supplying high-frequency power to the coil,
When processing the surface of the substrate while relatively moving the chamber and the substrate in a direction perpendicular to the longitudinal direction of the opening,
The housing from between the dielectric tube, to supply gas to the cylindrical chamber along the surface of the dielectric tube and the housing,
A plasma processing method characterized by the above.

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