JP5617818B2 - Inductively coupled plasma processing apparatus and inductively coupled plasma processing 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, and the like The present invention relates to an inductively coupled plasma processing apparatus and an inductively coupled plasma processing 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 sealed 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. 10 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” refers to relatively moving the semiconductor film 37 (and the substrate 36 supporting the semiconductor film 37) and the thermal plasma 35, and moving only one or both of them. 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. 11 is a conceptual diagram showing the relationship between the depth from the outermost surface and the temperature. As shown in the figure, by moving the thermal plasma 35 at a high speed, only the vicinity of the surface can be processed at a high temperature. 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.

  Further, a method for generating a long plasma using a microstrip line is disclosed (for example, see Patent Document 8). In this configuration, it is considered that the chamber wall surface in contact with the plasma cannot be completely cooled (not surrounded by the water-cooled flow path), and therefore cannot operate as a thermal plasma source.

  Moreover, what forms a linear elongate plasma torch by arranging a plurality of discharge electrodes in a line is disclosed (see, for example, Patent Document 9).

  An apparatus for performing etching or CVD that uses a planar spiral coil is disclosed (see, for example, Patent Document 10), which generates a large area plasma in a vacuum and forms a base material. Are related to a technical field different from the technical field of the present invention.

  In addition, an apparatus for performing etching or CVD that uses multiple vortex coils or multiple spiral coils has been disclosed (see, for example, Patent Document 11). And is related to a technical field different from the technical field of the present invention.

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 Special table 2010-539336 JP 2009-158251 A JP-A-3-79025 Japanese Patent Laid-Open No. 08-83696

S. Higashi, H .; Kaku, T .; Okada, H .; Murakami and S.M. Miyazaki, Jpn. J. et al. Appl. Phys. 45, 5B (2006) pp. 4313-4320

  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 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, the technique described in Patent Document 9 shown in the conventional example is inferior in thermal plasma stability (large time change) as compared to the inductively coupled high-frequency plasma torch described above, and is based on the electrode material. There is a disadvantage that there is a lot of contamination (contamination) in the material.

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 or a plasma and a reactive gas flow simultaneously. in the base material for low-temperature plasma treatment Te, and its object is to provide an inductively coupled plasma processing apparatus and an inductively coupled plasma processing method can be processed in a short time the entire desired to be processed areas of the substrate.

The inductively coupled plasma processing apparatus of the first invention of the present application has a long and linear opening, a long shape in a direction parallel to the longitudinal direction of the opening, and communicates with the opening. A long chamber surrounded by a dielectric member; a gas supply pipe for introducing gas into the long chamber; and a coil having a long shape in a direction parallel to the longitudinal direction of the opening. An inductively coupled plasma torch unit comprising: a high-frequency power source connected to the coil; provided outside the long chamber; and a substrate placed thereon to eject gas from the opening A substrate mounting table arranged in a direction, and a moving mechanism that allows the long chamber and the substrate mounting table to move relative to each other in a direction perpendicular to the longitudinal direction of the opening, The coil is composed of a plurality of conductor pieces, and each conductor piece is independent. Not made one round or more annular, and the entire coil is characterized in that an annular at least one round.

  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, the entire desired region to be treated of the substrate can be processed in a short time.

  In the plasma processing apparatus of the first invention of the present application, preferably, the coil preferably has a spiral shape as a whole.

  With such a configuration, a plasma processing apparatus can be realized with a simple configuration.

  In this case, it is preferable that the spiral coil is planar.

  With such a configuration, a plasma processing apparatus can be realized with a simpler configuration.

  Preferably, the inner wall surface of the chamber close to the spiral coil is a plane parallel to the plane formed by the spiral coil.

  With such a configuration, a plasma processing apparatus with high plasma generation efficiency can be realized.

  Preferably, the chamber is configured as a space sandwiched between two dielectric plates having at least one groove.

  With such a configuration, a plasma processing apparatus can be realized with a simple configuration.

Preferably, the maximum cross-sectional area of the long chamber is larger than the outer shape of the spiral coil .

  With such a configuration, a plasma processing apparatus with high plasma generation efficiency can be realized.

  Preferably, when defining “depth of the chamber” = “length of the chamber in the direction from the spiral coil to the chamber”, the depth of the chamber is 0.5 mm or more and 7 mm or less. It is desirable to be. More preferably, the depth of the chamber is 1 mm or more and 5 mm or less.

  With such a configuration, a plasma processing apparatus with high plasma generation efficiency can be realized.

  The opening may be provided on the opposite side of the spiral coil in the chamber, and the direction from the opening to the chamber and the direction from the spiral coil to the chamber are mutually different. It may be vertical.

  Alternatively, the coil may be disposed so as to surround the chamber, and may have a solenoid shape as a whole.

  With such a configuration, a plasma processing apparatus can be realized with a simple configuration.

The inductively coupled plasma processing method of the second invention of the present application is directed to a substrate from a slit-like opening formed in the long chamber while supplying gas into the long chamber surrounded by a dielectric member. Gas is ejected and has a long shape in a direction parallel to the longitudinal direction of the long chamber, and is composed of a plurality of conductor pieces, each conductor piece alone does not form a ring of one or more rounds, And as a whole, it is an inductively coupled plasma processing method for generating a high-frequency electromagnetic field in the long chamber by supplying high-frequency power to an annular coil having at least one round, and the longitudinal direction of the opening provided the elongated chamber and said substrate move relative products et al., outside of being arranged in a direction to eject gas from the opening by flop plasma and the long chamber perpendicular orientation relative the group was The surface of the material is treated.

  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, the entire desired region to be treated of the substrate can be processed 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. In this case, the entire desired region to be treated of the substrate can be processed 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 2 of this invention. The top view which shows the structure of the spiral coil in Embodiment 1 and 2 of this invention The top view which shows the structure of the spiral coil in Embodiment 3 of this invention. The perspective view which shows the structure of the plasma processing apparatus in Embodiment 4 of this invention. Sectional drawing which shows the structure of the plasma processing apparatus in Embodiment 4 of this invention. The perspective view which shows the structure of the solenoid coil in Embodiment 5 of this invention. The perspective view which shows the structure of the solenoid coil in Embodiment 6 of this invention. Sectional drawing which shows the structure of the plasma processing apparatus in a prior art example 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 FIG. 1 and FIG.

  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 of the inductively coupled plasma torch unit cut along a plane parallel to the longitudinal direction and perpendicular to the substrate. 1B is a cross-sectional view taken along the broken line in FIG. 1A, and FIG. 1A is a cross-sectional view taken along the broken line 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 parts (parts) are arranged.

  1 and 2, the base material 2 is placed on the base material placing table 1. In the inductively coupled plasma torch unit T, a conductor-made planar and multiple vortex spiral coil 3 is disposed in the vicinity of the first quartz plate 4 and the second quartz plate 5. The spiral coil 3 is composed of two conductor pieces. Each conductor piece alone does not form a ring of one or more rounds, and the coil as a whole has a ring of almost one round. In order to generate plasma efficiently, it is necessary to configure each conductor piece so that a high-frequency current having the same phase flows in the circumferential direction.

  For example, by connecting the inner peripheral side ends 3a and 3b of each conductor piece to the high frequency power supply side (high voltage side) and connecting the outer peripheral side ends 3c and 3d of each conductor piece to the ground side, It is possible to flow a high-frequency current having the same phase in the circumferential direction. On the contrary, the end portions 3a and 3b on the inner circumference side of each conductor piece are connected to the ground side, and the end portions 3c and 3d on the outer circumference side of each conductor piece are connected to the high frequency power supply side (high voltage side). May be.

  The long chamber made of dielectric is defined by a space (space 7 inside the long chamber) surrounded by the second quartz plate 5 and the third quartz plate 6. The inner wall surface of the long chamber near the spiral coil 3 is a plane parallel to the plane formed by the spiral coil 3. In such a configuration, since the distance from the spiral coil 3 to the long chamber is equal at any part of the spiral coil 3, inductively coupled plasma can be generated with small high-frequency power, and efficient plasma generation is possible. realizable. Further, the outer shape of the long chamber is configured to be larger than the outer shape of the spiral coil 3. Such a configuration also leads to an equal distance from the spiral coil 3 to the long chamber at an arbitrary portion of the spiral coil 3, so that a plasma processing apparatus with high plasma generation efficiency can be realized.

  The inductively coupled plasma torch unit T is entirely surrounded by a shield member (not shown) made of a grounded conductor, which can effectively prevent high-frequency leakage (noise) and effectively prevent undesirable abnormal discharge. Can be prevented.

  The space 7 inside the long chamber is surrounded by a flat surface forming one side of the second quartz plate 5 and a recess (groove) provided in the third quartz plate 6. That is, the entire long chamber is surrounded by a dielectric. The plasma generated in the space 7 inside the long chamber is ejected toward the base material 2 from the plasma ejection port 8 as a slit-like opening in the long chamber. Further, the longitudinal direction of the long chamber and the longitudinal direction of the plasma jet outlet 8 are arranged in parallel. Further, the plasma jet port 8 is provided on the opposite side to the spiral coil 3 in the long chamber.

  A plasma gas manifold 9 surrounded by a recess (groove) provided in the first quartz plate 4 and a flat surface (a surface opposite to the long chamber) forming one surface of the second quartz plate 5 is provided. The gas supplied to the plasma gas manifold 9 from the plasma gas supply pipe 10 passes through a plasma gas supply hole 11 as a long gas introduction portion provided in the second quartz plate 5, and is a space 7 inside the long chamber. To be introduced. With such a configuration, a uniform gas flow in the longitudinal direction can be easily realized. The flow rate of the gas introduced into the plasma gas supply pipe 10 is controlled by providing a flow rate control device such as a mass flow controller upstream thereof.

  The plasma gas supply hole 11 is a long slit, but a plurality of round holes may be provided in the longitudinal direction.

  The spiral coil 3 is bonded (bonded) to the first quartz plate 4 with an adhesive 12. Further, the central axis of the spiral coil 3 is arranged in parallel with the longitudinal direction of the long chamber and the longitudinal direction of the plasma ejection port 8.

  Further, a straight line (dotted line A in FIG. 2) parallel to the longitudinal direction of the spiral coil 3 and passing through the center of the long chamber parallel to the longitudinal direction of the long chamber (dotted line in FIG. 2). B), a straight line parallel to the longitudinal direction of the plasma gas supply hole 11 and passing through the center of the plasma gas supply hole 11 (dotted line C in FIG. 2), and parallel to the longitudinal direction of the plasma outlet 8 and the center of the plasma outlet 8 The straight lines passing through (dotted line D in FIG. 2) are arranged in parallel and on the same plane. With such a configuration, the volume of the portion that generates plasma can be minimized while obtaining uniform plasma, so that a plasma processing apparatus with high plasma generation efficiency can be realized.

  Further, a shield gas nozzle 13 as a shield gas supply port is disposed in a portion close to the substrate mounting table 1, and a shield gas manifold 14 is provided therein. In this way, two systems of gas introduction are prepared, and a shielding gas is supplied in addition to the plasma gas suitable for plasma generation, such as oxygen and carbon dioxide in the atmosphere, which are unnecessary or have an adverse effect on the processing. It is possible to reduce contamination of the plasma irradiation surface. The shield gas supply port may be a slit having a shape that is long in a direction parallel to the long direction of the plasma outlet 8, or may be in a direction parallel to the long direction of the plasma outlet 8. It may be a number of holes arranged side by side.

  The spiral coil 3 is hollow, and the inside is a refrigerant flow path. That is, cooling water as a coolant flows inside the spiral coil 3, and cooling of the spiral coil 3 and cooling of the first quartz plate 4 joined thereto are realized. A water cooling tube 15 made of a conductor serving as a refrigerant flow path is joined to the third quartz plate 6 by an adhesive 12. The water-cooled tube 15 is electrically grounded and is configured to facilitate plasma ignition (ignition).

  The first quartz plate 4, the second quartz plate 5, and the third quartz plate 6 are bonded (bonded) to each other, and the inductively coupled plasma torch unit T is effectively cooled by increasing the thermal conductivity of each other. It is configured to be.

  Joining of spiral coil 3 and first quartz plate 4, joining of water-cooled tube 15 and third quartz plate 6, joining of first quartz plate 4 and second quartz plate 5, second quartz plate 5 and first quartz plate 4. The joining with the three quartz plates 6 can be performed by using various adhesives in addition to those by a welding method. In order to ensure cooling efficiency, when using an adhesive, it is preferable to apply it as thinly as possible and uniformly.

  The advantage of the structure in which the spiral coil 3 and the water-cooled tube 15 are joined to the first quartz plate 4 and the third quartz plate 6, respectively, is that they can be manufactured at low cost and with short delivery time because existing plate materials and pipe materials can be used. The cooling efficiency is good because the distance between the long chamber and the coolant channel can be reduced. That is, in the present embodiment, since the cross section of the refrigerant flow path is circular, a much larger amount of refrigerant than in the case of water-cooling as a double tube configuration in the technique described in Patent Document 6 shown in the conventional example. Effective cooling is possible.

  A rectangular slit-shaped plasma ejection port 8 is provided, and the substrate mounting table 1 (or the substrate 2 on the substrate mounting table 1) is disposed to face the plasma ejection port 8. In this state, high-frequency power is supplied to the spiral coil 3 from a high-frequency power source (not shown) while gas is being jetted from the plasma nozzle 8 toward the substrate 2 while gas is being supplied into the long chamber. The thin film 22 on the substrate 2 can be plasma-treated by generating plasma in the space 7 inside the long chamber and irradiating the substrate 2 with the plasma from the plasma outlet 8. The base material 2 is processed by relatively moving the long chamber and the base material mounting table 1 in a direction perpendicular to the longitudinal direction of the plasma ejection port 8. 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.

  Various gases can be used as the gas supplied into the long chamber. However, considering the stability of the plasma, the ignitability, the life of the member exposed to the plasma, etc., it is desirable that the main gas is an inert gas. Among these, Ar gas is typically used. When plasma is generated only by Ar, the plasma becomes considerably high temperature (10,000 K or more).

  In this configuration, since the length in the longitudinal direction of the plasma outlet 8 is equal to or larger than the width of the base material 2, a single scan (the inductively coupled plasma torch unit T and the base material mounting table 1 is performed). The entire thin film 22 in the vicinity of the surface of the substrate 2 can be processed by relatively moving).

In such a plasma processing apparatus, a high-frequency power source (not shown) is supplied while Ar or Ar + H ₂ gas is supplied from a gas outlet into a long chamber and gas is jetted from the plasma outlet 8 toward the substrate 2. Further, by supplying high frequency power of 13.56 MHz to the spiral coil 3, plasma is generated by generating a high frequency electromagnetic field in the space 7 inside the long chamber, and the plasma is supplied from the plasma outlet 8 to the substrate 2. By performing irradiation and scanning, heat treatment such as crystallization of a semiconductor film can be performed.

As conditions for plasma generation, the distance between the plasma jet port 8 and the substrate 2 = 3 to 50 mm, the scanning speed = 50 to 3000 mm / s, the total plasma gas flow rate = 1 to 100 SLM, the H ₂ concentration in Ar + H ₂ gas = 0-10%, shielding gas (N ₂₎ flow rate = 1～100SLM, a value of about RF power = 0.5～10KW appropriate. However, among these quantities, the gas flow rate and power are values per 100 mm of the length of the plasma jet port 8. This is because it is considered appropriate to input parameters proportional to the length of the plasma jet port 8 for parameters such as gas flow rate and electric power.

  As described above, the long chamber and the substrate mounting table 1 are arranged in a direction perpendicular to the longitudinal direction of the plasma nozzle 8 while the longitudinal direction of the plasma nozzle 8 and the substrate mounting table 1 are arranged in parallel. Therefore, the length of the plasma to be generated and the processing length of the substrate 2 can be configured to be substantially equal. In addition, the width of the cross section obtained by cutting the long chamber along a plane perpendicular to the central axis (the width of the space 7 inside the long chamber in FIG. 1A) is the width of the plasma ejection port 8 (FIG. 1A It may be a little larger than the width of the gap). 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.

  If the “depth of the space 7 inside the long chamber” is defined as “the length of the long chamber in the direction from the spiral coil 3 to the long chamber”, the depth of the space 7 inside the long chamber is defined. This corresponds to d in FIG. When the experiment was conducted at atmospheric pressure with the length (length in the longitudinal direction) of the space 7 inside the long chamber being 95 mm and changing the depth d, when the depth d was 1 mm or more and 5 mm or less, the high frequency power was 10 kW. In the following, thermal plasma was successfully generated by Ar gas. If the high frequency power is further increased, it is considered that thermal plasma is generated even when the depth d is 0.5 mm or more and 7 mm or less, but if it is out of this range, inductively coupled plasma processing at atmospheric pressure is difficult. From this experimental result, it can be said that the depth d is preferably 0.5 mm or more and 7 mm or less, and more preferably, the depth d is 1 mm or more and 5 mm or less. This also indicates that the volume of the space 7 inside the long chamber may be small, and it is considered that high power efficiency can be obtained as compared with the conventional example.

  In the present embodiment, multiple vortex spiral coils 3 are used. The advantages will be described below. The impedance of the coil should not be less than 5 times, preferably less than 2 times the characteristic impedance (usually 50Ω) of the cable connecting the high frequency power supply and the matching circuit (provided between the high frequency power supply and the coil). It is difficult to obtain a good alignment state. When it is desired to process a large base material 2, that is, when the processing length of the base material 2 (for example, the length or diameter of the short side of the base material 2) is increased, the length of the spiral coil in the longitudinal direction is It is necessary to lengthen it accordingly. However, when a simple spiral spiral coil is used, as the coil becomes longer, the coil inductance (proportional to the impedance) increases, making it difficult to obtain a good matching state.

  On the other hand, in this embodiment, multiple vortex spiral coils 3 are used. The spiral coil 3 is composed of two conductor pieces. Each conductor piece alone does not form a ring of one or more rounds, and the coil as a whole has a ring of almost one round. And it is set as the structure which supplies a high frequency electric power in parallel with respect to each conductor piece. Since each conductor piece alone does not form a ring of more than one turn, the current path is shorter than a simple spiral spiral coil (which needs to form a ring of at least one turn). Furthermore, since these are connected in parallel, the spiral coil 3 as a whole has a very small inductance.

  Thereby, even when the processing length of the base material 2 (for example, the length or the diameter of the short side of the base material 2) is increased, a low inductance coil that can obtain a good matching state can be realized. The entire coil needs to have at least one circular shape. This is essential for the generation of high temperature inductively coupled plasma.

(Embodiment 2)
The second embodiment of the present invention will be described below with reference to FIGS.

  FIG. 3 shows the configuration of the plasma processing apparatus according to Embodiment 2 of the present invention, and is an assembly configuration diagram of an inductively coupled plasma torch unit, in which perspective views of parts (part) are arranged. .

  In FIG. 3, a conductor-made planar and multiple vortex spiral coil 3 is arranged in the vicinity of the first quartz plate 4 and the second quartz plate 5. The spiral coil 3 is composed of four conductor pieces, and each conductor piece alone does not form a ring of more than one turn, and the coil as a whole has a ring of substantially one turn. In order to generate plasma efficiently, it is necessary to configure each conductor piece so that a high-frequency current having the same phase flows in the circumferential direction.

  For example, the inner ends 3e, 3f, 3g and 3h of each conductor piece are connected to the high frequency power supply side (high voltage side), and the outer ends 3i, 3j, 3k and 3m of each conductor piece are connected to each other. By connecting to the ground side, it is possible to flow a high-frequency current having the same phase in the circumferential direction. On the contrary, the end portions 3e, 3f, 3g and 3h on the inner peripheral side of each conductor piece are connected to the ground side, and the end portions 3i, 3j, 3k and 3m on the outer peripheral side of each conductor piece are supplied with high frequency power. You may connect to the side (high voltage side).

  In such a configuration, the length of each conductor piece (the length of the current path) is further shorter than in the first embodiment, and the inductance can be further reduced.

  FIG. 4 is a plan view showing the configuration of the spiral coil in the first and second embodiments of the present invention. 4A is a simple vortex spiral coil 3, FIG. 4B is a multiple (double) vortex spiral coil 3 used in the first embodiment, and FIG. The shape of the multiple (quadruple) vortex spiral coil 3 used in the second embodiment is shown.

  In the above description, the double and quadruple vortex spiral coils 3 are illustrated, but a spiral coil having a multiplicity of triple or fivefold or more can also be used.

(Embodiment 3)
Hereinafter, a third embodiment of the present invention will be described with reference to FIG.

  FIG. 5 is a plan view showing the configuration of the spiral coil according to Embodiment 3 of the present invention.

  In FIG. 5, a conductor-made planar and multiple vortex spiral coil 3 is used. The multiplicity of the coil is four. The spiral coil 3 is composed of four conductor pieces, and each conductor piece alone does not form a ring of more than one turn, and the coil as a whole has a ring of substantially one turn. Further, the inner peripheral end of each conductor piece is coupled at the center of the spiral coil 3.

(Embodiment 4)
Hereinafter, a fourth embodiment of the present invention will be described with reference to FIGS.

  FIG. 6 shows the configuration of the plasma processing apparatus according to the fourth embodiment of the present invention, and is an assembly configuration diagram of an inductively coupled plasma torch unit, in which perspective views of parts (part) are arranged. . FIG. 7 is a cross-sectional view taken along a plane perpendicular to the longitudinal direction of the inductively coupled plasma torch unit.

  6 and 7, the long chamber made of a dielectric is composed of a quartz plate 17 provided below the lid 16, a cylindrical quartz tube 18, and a quartz having a narrow opening at one end. It is defined by a space surrounded by the nozzle 19 (space 7 inside the long chamber). The lower surface of the quartz tube 18 and the upper surface of the quartz nozzle 19 are joined in an annular shape without a gap. A plurality of helical solenoid coils 20 made of a conductor are arranged around the quartz tube 18 so as to surround the long chamber. The inner wall surface of the long chamber on the side close to the solenoid coil 20 forms a surface parallel to the cylindrical shape of the solenoid coil 20 as a whole.

  In such a configuration, since the distance from the solenoid coil 20 to the long chamber is equal at any part of the solenoid coil 20, inductively coupled plasma can be generated with a small high frequency power, and efficient plasma generation can be achieved. realizable. The solenoid coil 20 is composed of three U-shaped conductor pieces 20a, 20b, and 20c. Each conductor piece alone does not form a ring of one or more rounds, and the coil as a whole has a ring of approximately three turns. . In order to generate plasma efficiently, it is necessary to configure each conductor piece so that a high-frequency current having the same phase flows in the circumferential direction.

  The inductively coupled plasma torch unit T is entirely surrounded by a shield member (not shown) made of a grounded conductor, which can effectively prevent high-frequency leakage (noise) and effectively prevent undesirable abnormal discharge. Can be prevented.

  The space 7 inside the long chamber is surrounded by a quartz plate 17, a quartz tube 18, and a quartz nozzle 19. That is, the entire long chamber is surrounded by a dielectric. The plasma generated in the space 7 inside the long chamber is formed into a base material from a plasma outlet 8 as a slit-like opening (a narrower opening provided below the quartz nozzle 19) in the long chamber. Erupts towards Further, the longitudinal direction of the long chamber and the longitudinal direction of the plasma jet outlet 8 are arranged in parallel.

  A plasma gas manifold 9 is provided that is surrounded by a recess (groove) provided in the lid 16 and a flat surface (surface opposite to the long chamber) forming one surface of the quartz plate 17. The gas supplied from the plasma gas supply pipe 10 to the plasma gas manifold 9 passes through a plasma gas supply hole 11 (through hole) as a long gas introduction portion provided in the quartz plate 17 and is provided inside the long chamber. It is introduced into the space 7. With such a configuration, a uniform gas flow in the longitudinal direction can be easily realized. The flow rate of the gas introduced into the plasma gas supply pipe 10 is controlled by providing a flow rate control device such as a mass flow controller upstream thereof.

  The plasma gas supply hole 11 is a long slit, but a plurality of round holes may be provided in the longitudinal direction.

  The central axis of the solenoid coil 20 is disposed so as to coincide with the central axis of the long chamber and the central axis of the plasma ejection port 8.

  In order to effectively cool the quartz tube 18, the solenoid coil 20 may be bonded to the quartz tube 18, and a coolant such as cooling water may be passed through the hollow solenoid coil 20.

  In the present embodiment, a multiple helical solenoid coil 20 is used. The advantages will be described below. The impedance of the coil should not be less than 5 times, preferably less than 2 times the characteristic impedance (usually 50Ω) of the cable connecting the high frequency power supply and the matching circuit (provided between the high frequency power supply and the coil). It is difficult to obtain a good alignment state. When it is desired to process a large base material 2, that is, when the processing length of the base material 2 (for example, the length or diameter of the short side of the base material 2) is increased, the length of the solenoid coil in the longitudinal direction is It is necessary to lengthen it accordingly.

  However, when a simple spiral solenoid coil is used, as the coil becomes longer, the coil inductance (proportional to the impedance) increases, making it difficult to obtain a good matching state. On the other hand, in the present embodiment, a multiple helical solenoid coil 20 is used. The solenoid coil 20 is composed of three U-shaped conductor pieces, and each conductor piece alone does not form a ring of one or more rounds, and the coil as a whole has a ring of approximately three turns. And it is set as the structure which supplies a high frequency electric power in parallel with respect to each conductor piece. Since each conductor piece alone does not form a ring of more than one turn, the current path is shorter than a simple spiral solenoid coil (which needs to form a ring of at least one turn).

  Furthermore, since these are connected in parallel, the solenoid coil 20 as a whole has a very small inductance. Thereby, even when the processing length of the base material 2 (for example, the length or the diameter of the short side of the base material 2) is increased, a low inductance coil that can obtain a good matching state can be realized. The entire coil needs to have at least one circular shape. This is essential for the generation of high temperature inductively coupled plasma.

(Embodiment 5)
The fifth embodiment of the present invention will be described below with reference to FIG.

  FIG. 8 is a perspective view showing the configuration of the solenoid coil according to the fifth embodiment of the present invention.

  In FIG. 8, the solenoid coil 20 is composed of two conductor pieces 20d and 20e, and each conductor piece alone does not form a ring of one or more rounds, and the coil as a whole has a ring of substantially one and a half rounds. The conductor pieces 20d and 20e are disposed at positions slightly apart in the vertical direction.

(Embodiment 6)
Hereinafter, a sixth embodiment of the present invention will be described with reference to FIG.

  FIG. 9 is a perspective view showing the configuration of the solenoid coil according to the sixth embodiment of the present invention.

  In FIG. 9, the solenoid coil 20 is composed of two conductor pieces 20f and 20g, and each conductor piece alone does not form a ring of one or more rounds, and the coil as a whole has a ring of substantially one and a half rounds. The conductor pieces 20f and 20g are arranged at positions that are hardly separated in the vertical direction.

  In the above description, the double and triple helical solenoid coils 20 are illustrated, but it is also possible to use solenoid coils having a multiplicity of four or more.

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

  For example, 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.

  Moreover, although the case where the spiral coil 3 was planar was illustrated, the spiral coil 3 does not necessarily need to be a plane. For example, a configuration using a so-called bell-shaped spiral coil in which the distance between the spiral coil 3 and the first quartz plate 4 gradually increases toward the center of the vortex.

  Moreover, although the case where the plasma jet port 8 is provided on the opposite side to the spiral coil 3 in the long chamber is illustrated, the direction from the plasma jet port 8 to the long chamber and the long length from the spiral coil 3 are illustrated. The configuration may be such that the directions to the chambers are perpendicular to each other.

  In addition, the various configurations of the present invention enable high-temperature treatment of the vicinity of the surface of the base material 2, but for crystallization of a TFT semiconductor film and modification of a solar cell semiconductor film described in detail in the conventional example. Of course, it can be applied to cleaning and reducing degassing of the protective layer of plasma display panels, flattening and reducing degassing of dielectric layers composed of aggregates of silica particles, reflow of various electronic devices, solid impurities It can be applied to various surface treatments such as plasma doping using a source. 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.

  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, the plasma by the reaction gas is irradiated onto the substrate, and etching and CVD can be realized. Alternatively, the plasma and the reactive gas flow are simultaneously irradiated onto the substrate by supplying a gas containing a reactive gas as a shielding gas while using a rare gas or a gas obtained by adding a small amount of H ₂ gas to the rare gas as the plasma gas. In addition, plasma processing such as etching, CVD, and doping can be realized. When a gas containing argon as a main component is used as the plasma gas, thermal plasma is generated as exemplified in detail in the embodiment. On the other hand, when a gas containing helium as a main component is used as the plasma 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, Uniformity in the vicinity of the surface of the substrate for only a short time in various surface treatments such as surface flattening of dielectric layers consisting of aggregates, reduction of degassing, reflow of various electronic devices, plasma doping using solid impurity sources, etc. In the high temperature heat treatment, the present invention is useful for treating the entire desired region of the base material in a short time.

  In addition, it is a useful invention for processing a desired whole region of a substrate in a short time in low temperature plasma processing such as etching, film formation, doping, and surface modification in manufacturing various electronic devices. .

DESCRIPTION OF SYMBOLS 1 Substrate mounting base 2 Substrate T Inductively coupled plasma torch unit 3 Spiral coil 4 First quartz plate 5 Second quartz plate 6 Third quartz plate 7 Space inside long chamber 8 Plasma outlet 9 Plasma gas manifold 10 Plasma Gas supply pipe 11 Plasma gas supply hole 12 Adhesive 13 Shield gas nozzle 14 Shield gas manifold 15 Water-cooled tube 22 Thin film

Claims (12)

A long, linear opening;
A long chamber having an elongated shape in a direction parallel to the longitudinal direction of the opening, communicating with the opening, and surrounded by a dielectric member;
A gas supply pipe for introducing gas into the long chamber;
A coil having a long shape in a direction parallel to the longitudinal direction of the opening, and an inductively coupled plasma torch unit,
A high-frequency power source connected to the coil;
A substrate mounting table provided outside the long chamber and disposed in a direction in which the substrate is mounted and gas is ejected from the opening ;
A moving mechanism capable of relatively moving the long chamber and the substrate mounting table in a direction perpendicular to the longitudinal direction of the opening,
The coil is composed of a plurality of conductor pieces, each conductor piece alone does not form a ring of one or more rounds, and the coil as a whole has a ring of at least one round,
An inductively coupled plasma processing apparatus.
The plasma processing apparatus according to claim 1, wherein the coil is a spiral coil having a spiral shape as a whole. The plasma processing apparatus according to claim 2, wherein the spiral coil is planar. The plasma processing apparatus according to claim 3, wherein an inner wall surface of the chamber close to the spiral coil is a plane parallel to a plane formed by the spiral coil. The plasma processing apparatus according to claim 2, wherein the chamber is configured as a space sandwiched between two dielectric plates each having a groove. The inductively coupled plasma processing apparatus according to claim 2 , wherein a maximum cross-sectional area of the long chamber is larger than an outer shape of the spiral coil .
The depth of the chamber is 0.5 mm or more and 7 mm or less when defined as “depth of the chamber” = “length of the chamber in the direction from the spiral coil to the chamber”. Plasma processing equipment. The plasma according to claim 2, wherein the depth of the chamber is 1 mm or more and 5 mm or less when defining "depth of the chamber" = "length of the chamber in the direction from the spiral coil to the chamber". Processing equipment. The plasma processing apparatus according to claim 2, wherein the opening is provided in the chamber on a side opposite to the spiral coil. The plasma processing apparatus according to claim 2, wherein a direction from the opening to the chamber and a direction from the spiral coil to the chamber are perpendicular to each other. The plasma processing apparatus according to claim 1, wherein the coil is disposed so as to surround the long chamber and has a solenoid shape as a whole. While gas is supplied into the long chamber surrounded by the dielectric member, the gas is ejected from the slit-shaped opening formed in the long chamber toward the base material,
The long chamber has a long shape in a direction parallel to the longitudinal direction of the long chamber, and is composed of a plurality of conductor pieces. Each conductor piece alone does not form a ring of one or more rounds, and as a whole, at least one round. An inductively coupled plasma processing method for generating a high-frequency electromagnetic field in the long chamber by supplying high-frequency power to the annular coil of
The elongated chamber and the base material and the relatively moving article al, are arranged in a direction to eject gas from the opening by flop plasma and the length direction perpendicular to the longitudinal direction of the opening Treating the surface of the substrate provided outside the length chamber ;
An inductively coupled plasma processing method.

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