JP5500098B2 - Inductively coupled 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, and the like. The present invention relates to an inductively coupled 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. 9 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. 10 is a conceptual diagram showing the relationship between the depth from the outermost surface and the temperature. As shown in FIG. 10, 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.

  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 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 JP 2009-158251 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

  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, the technique described in Patent Document 8 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 by the reactive gas or plasma and the reactive gas flow at the same time. Thus, an object of the present invention is to provide an inductively coupled plasma processing apparatus and method capable of processing the entire desired region of the substrate in a short time when the substrate is subjected to low temperature plasma treatment.

Inductively coupled plasma processing apparatus of the first aspect of the present invention is a switch Yanba having a space long surrounded by a dielectric, and a gas inlet for supplying gas into said space, parallel to the space of the elongated provided, and a hole elongated surrounded by a dielectric, and a conductor rod disposed in the hole of the long, a high frequency power source connected to said conductor rod, slits like in communication with the space In the inductively coupled plasma processing apparatus having a substrate mounting table that is disposed opposite to the opening and that holds the substrate, the conductor rod includes a plurality of conductor rods, and the plurality of conductors By electrically connecting the rods at the end portions, the conductor rods as a whole constitute a coil, and the plurality of conductor rods are arranged across the space, and the longitudinal direction of the chamber and the longitudinal length of the opening portion It is arranged in parallel with the direction, and with respect to the longitudinal direction of the opening Immediately orientation, characterized by comprising a moving mechanism that allows relative movement between the chamber and the substrate mounting table.

  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, in an arbitrary cross section cut by a plane perpendicular to the longitudinal direction including the chamber, the distance between the conductor rod and a conductor other than the conductor rod is It is desirable that the distance is greater than the distance between the conductor rod and the chamber.

  With such a configuration, it becomes possible to generate plasma with higher efficiency.

  Further, in this case, it is preferable that a high-frequency current having an opposite phase flows through a plurality of the conductive rods that are opposed to each other across the chamber, or a high-frequency current having the same phase flows. It may be configured as follows.

  Further, it is preferable that the refrigerant is configured to flow through the long hole.

  With such a configuration, effective cooling of the plasma processing apparatus can be realized.

Also, preferably, the holes of the elongated separately, it is desirable that the coolant channel of the hole and parallel to the long of the long is provided in the dielectric.

  With such a configuration, effective cooling of the plasma processing apparatus can be realized.

In this case, preferably, the hole and before Kihiya Nakadachiryuro of the long, it is preferable to refrigerant manifold communicating respectively provided in the longitudinal direction of both the front edge of the winding Yanba.

  With such a configuration, a more compact and simple plasma processing apparatus can be realized.

Preferably, the dielectric is housed in a conductor case grounded through an air layer.

  With such a configuration, abnormal discharge can be suppressed. Moreover, the weight of the plasma processing apparatus can be reduced.

  Further, the long hole may be composed of a dielectric cylindrical tube.

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

In this case, preferably, before the winding Yanba it may be formed of a gap between the plurality of bundled dielectric cylinder made of pipe.

  With such a configuration, a more inexpensive plasma processing apparatus can be realized.

The front direction perpendicular to the longitudinal direction of the width of Kichi Yanba may be wider configuration than direction perpendicular to the longitudinal direction of width of the opening.

  With such a configuration, stable plasma processing can be realized.

Inductively coupled plasma processing method of the second aspect of the present invention, while supplying a gas into the switch Yanba having a space long surrounded by a dielectric, the substrate from the space and the slits shaped opening communicating Inductive coupling that generates a high-frequency electromagnetic field in the chamber by ejecting a gas toward the coil and supplying high-frequency power to a coil made of a conductive rod provided in a long hole surrounded by the dielectric In the type plasma processing method, the plurality of conductor rods are composed of a plurality of wires, and the plurality of conductor rods are electrically connected at their ends so that the conductor rods as a whole constitute a coil, while the plurality of conductor rods are the spaces And the longitudinal direction of the chamber and the longitudinal direction of the opening are disposed in parallel, and the chamber and the substrate mounting table are arranged in a direction perpendicular to the longitudinal direction of the opening. While relatively moving Characterized by treating the surface of Kimotozai.

  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. Sectional drawing which shows the structure of the plasma processing apparatus in Embodiment 2 of this invention. Sectional drawing which shows the structure of the plasma processing apparatus 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 5 of this invention. The perspective view which shows the structure of the plasma processing apparatus in Embodiment 6 of this invention. Sectional drawing which shows the structure of the plasma processing apparatus in Embodiment 7 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. FIGS. 1B and 1C are cross-sectional views taken along a plane parallel to the longitudinal direction of the inductively coupled plasma torch unit and perpendicular to the substrate. 1B is a cross-sectional view taken along broken lines A to A ′ in FIG. 1A, and FIG. 1C is a cross-sectional view taken along broken lines B to B ′ in FIG. 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 copper rod 3 as a conductor rod forming a coil is arranged inside a quartz block 4 constituting a long chamber made of a dielectric. The quartz block 4 is accommodated in a portion surrounded by a brass block 5 and a brass lid 6 provided around the quartz block 4. Since the brass block 5 and the brass lid 6 are grounded, high-frequency leakage (noise) can be effectively prevented and undesirable abnormal discharge can be effectively prevented.

  A space 7 inside the long chamber is a slit provided in the quartz block 4. That is, the long chamber is surrounded by the 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.

  A plasma gas manifold 9 is provided above the brass lid 6. The gas supplied to the plasma gas manifold is longer in the chamber than the plasma gas supply hole 11 as a gas inlet provided in the quartz block 4 via the plasma gas supply pipe 10 including the hole provided in the quartz block 4. It is introduced into the internal space 7. Since a plurality of plasma gas supply pipes 10 are provided in the longitudinal direction, a uniform gas flow can be easily formed in the longitudinal direction.

  Four copper rods 3 are provided, and these are electrically connected at the end portions so as to constitute a coil as a whole. Each copper bar 3 is provided in parallel to the long chamber and in a copper bar insertion hole 12 which is a long hole surrounded by quartz which is a dielectric.

  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, 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 quartz block 4 and the brass block 5 are provided with a cooling water pipe 15 penetrating them. The copper rod insertion hole 12 and the cooling water pipe 15 are water paths (refrigerant flow paths) arranged in parallel with each other, and a refrigerant formed by a space between the resin case 17 provided on the outside of the brass block 16 and the brass block 16. It communicates with a cooling water manifold 18 as a manifold. The resin case 17 is provided with a cooling water inlet / outlet as a refrigerant inlet / refrigerant outlet (not shown), and the water cooling pipe is routed to the torch unit T in a very simple manner. A torch can be constructed. That is, two refrigerant manifolds 18 are provided on both sides in the longitudinal direction of the long chamber, and refrigerant passages that communicate the two refrigerant manifolds 18 with each member are provided.

  The copper rods 3 are electrically connected by a coupler 19 in the cooling water manifold 18, and the four copper rods 3 as a whole form a spiral coil with two turns. Two of the copper bars 3 pass through the brass block 16 and are connected to the copper plate 20 through the high-frequency introduction terminal hole or the ground terminal hole provided in the resin case 17, and are connected to a high-frequency matching circuit (not shown) through the copper plate 20. Is done.

  Thus, in this Embodiment, since the copper rod insertion hole 12 and the cooling water piping 15 with a circular cross section which penetrate the quartz block 4 are provided, it describes in patent document 6 shown in the prior art example. A much larger amount of refrigerant can be allowed to flow than in the case of water cooling in the technology as a double tube configuration.

  The gas introduction to the plasma gas manifold 9 is realized via a plasma gas supply pipe 21 provided with a flow rate control device such as a mass flow controller upstream thereof.

  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 copper rod 3 forming a coil from a high-frequency power source (not shown) while gas is being injected from the plasma outlet 8 toward the substrate 2 while supplying gas into the long chamber. By doing so, plasma is generated in the space 7 inside the long chamber, and the substrate 2 is irradiated with the plasma from the plasma outlet 8, whereby the thin film 22 on the substrate 2 can be subjected to plasma treatment. 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 FIGS.

  The plurality of copper bars 3 are arranged in parallel, and the four copper bars 3 as a whole form a solenoid coil having a spiral shape and two turns. In other words, the high-frequency current in the opposite phase flows through the conductor rods facing each other across the long chamber among the plurality of conductor rods. In this case, in the cross section cut by a plane perpendicular to the longitudinal direction of the torch unit T, the induction electromagnetic field in the vicinity of the midpoint of the line segment connecting the centers of the conductor rods facing each other with the long chamber interposed therebetween becomes strong and efficient. Plasma generation can be realized.

  On the other hand, all four copper bars 3 are bundled in the cooling water manifold 18, high-frequency power is supplied to one side in the longitudinal direction, and the other side is grounded to all four copper bars 3. A high-frequency current having the same phase can also flow. In other words, among the plurality of conductor rods, a high-frequency current having the same phase may flow through the conductor rods facing each other with the long chamber interposed therebetween. In this case, in the cross section cut by a plane perpendicular to the longitudinal direction of the torch unit T, the induction electromagnetic field in the vicinity of the midpoint of the line segment connecting the centers of the opposing conductor rods across the long chamber is substantially zero. Since a strong induction electromagnetic field is generated near the upper and lower ends of the long chamber, efficient plasma generation can be realized.

  In this case, since the high-frequency current branches to the four copper rods, the current per one becomes small. In other words, when copper bars having the same thickness are used, the DC resistance and inductance of the entire coil are reduced. Therefore, the copper loss in the coil is reduced and the power efficiency is increased.

  By bundling two conductor rods arranged on the same side across the long chamber in the cooling water manifold 18, it is also possible to arrange coils having one winding in two stages in parallel. Also in this case, a high-frequency current having an opposite phase flows to a conductive rod facing the long chamber among the plurality of conductive rods, but the high-frequency current branches to two copper rods, so that the current per one Get smaller. In other words, when copper bars having the same thickness are used, the DC resistance and inductance of the entire coil are reduced. Therefore, the copper loss in the coil is reduced and the power efficiency is increased.

  The method of reducing the copper loss by such a device configuration 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 T is elongated in the longitudinal direction. .

  Moreover, in this structure, the distance between the copper rod 3 and the conductors (the brass block 5 and the brass lid 6) other than the copper rod 3 in an arbitrary cross section cut by a plane perpendicular to the longitudinal direction including the long chamber, It is larger than the distance between the copper rod 3 and the long chamber. Here, the distance between the copper bar 3 and the long chamber means the distance between the copper bar 3 and the space 7 inside the long chamber (a rectangular parallelepiped). In general, since the induction electromagnetic field formed by the high frequency current source is inversely proportional to the square of the distance from the high frequency current source, the distance between the copper bar 3 and a conductor other than the copper bar 3 is greater than the distance between the copper bar 3 and the long chamber. However, the electromagnetic field that induces eddy currents in the conductors other than the copper rod 3 is larger than the electromagnetic field effective for plasma generation, and the copper loss (eddy current loss) increases. In order to avoid this, the distance between the copper bar 3 and a conductor other than the copper bar 3 is configured to be larger than the distance between the copper bar 3 and the long chamber.

  In such a configuration, since it is necessary to maintain a certain distance between the copper rod 3 and the plasma jet port 8, the quartz is located closer to the plasma jet port 8 than the copper rod 3 closest to the plasma jet port 8. A cooling water pipe 15 for cooling the block 4 is provided. Similarly, a cooling water pipe 15 for cooling the quartz block 4 is also arranged at a portion closer to the brass lid 6 than the copper rod 3 closest to the brass lid 6.

  Further, even if the distance from the copper rod 3 is maintained in the brass block 5 and the brass lid 6, copper loss (eddy current loss) occurs. Therefore, in order to prevent problems caused by this, the cooling water pipe 15 is attached to the copper rod 3. It is provided near the site.

  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). A portion of the brass block 5 that is downstream of the plasma outlet 8 forms a space that gradually widens toward the substrate 2. With such a configuration, it is possible to suppress a decrease in the plasma density due to the plasma contact with the brass block 5, and at the same time, it is possible to provide the cooling water pipe 15 at a position close to the portion in contact with the plasma.

  In this configuration, since the length of the plasma injection port 8 in the longitudinal direction is equal to or greater than the width of the base material 2, one-time scanning (the torch unit T and the base material mounting table 1 are relatively moved). The entire thin film 22 in the vicinity of the surface of the substrate 2 can be processed.

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 copper rod 3 that forms the coil, a high frequency electromagnetic field is generated in the space 7 inside the long chamber to generate plasma, and the plasma is supplied from the plasma outlet 8 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 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. Further, the width of the cross section obtained by cutting the long chamber along a plane perpendicular to the central axis (the width of the chamber internal space 7 in FIG. 1A) is the width of the plasma ejection port 8 (the gap in FIG. 1A). The width may be the same as or slightly larger. 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 7 of the long chamber, a relatively uniform plasma can be generated in the long direction, so that the substrate can be processed uniformly compared to the conventional example disclosed in Patent Document 6. it can.

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

  FIG. 3 shows the configuration of the plasma processing apparatus according to Embodiment 2 of the present invention, which is a cross-sectional view taken along a plane perpendicular to the longitudinal direction of the inductively coupled plasma torch unit, and corresponds to FIG. To do.

  In the second embodiment of the present invention, only the shape of the quartz block 4 is different from that of the first embodiment, and therefore other explanations are omitted.

  In FIG. 3, a quartz block 4 is housed in a brass block 5 and a brass lid 6 as a grounded conductor case via an air layer.

  In Embodiment 1, when the torch unit is operated for a long time, an inert gas such as Ar enters the gap between the quartz block 4 and the brass block 5 or the brass lid 6, and abnormal discharge occurs in this gap. There is a case. In order to avoid this, an air layer is provided in the present embodiment. In order to suppress the retention of inert gas such as Ar more securely, a hole that allows the air layer to communicate with the space outside the torch unit is provided, or a fan or the like is used to connect the gas in the air layer and the space outside the torch unit. It is also effective to promote exchange with a certain gas.

Here, the explanation was made on the assumption that the atmosphere in the space outside the torch unit is air, but the atmosphere in the space outside the torch unit is an inert gas such as N _{2 that} has a high discharge start voltage at atmospheric pressure. In this case, the same effect is obtained. Alternatively, it is also effective to supply air, N ₂ or the like to the air layer using a flow rate control device to avoid retention of an inert gas such as Ar.

  Further, in the present embodiment, there is an advantage that the quartz block 4 and thus the torch unit T can be reduced in weight.

(Embodiment 3)
Embodiment 3 of the present invention will be described below with reference to FIG.

  FIG. 4 shows the configuration of the plasma processing apparatus according to Embodiment 3 of the present invention, which is a cross-sectional view of the inductively coupled plasma torch unit cut along a plane perpendicular to the longitudinal direction, and corresponds to FIG. To do.

  In FIG. 4, in place of the quartz block 4 in the first embodiment, a large number of quartz tubes 23 are provided. That is, the copper rod insertion hole 12 and the cooling water pipe 15 as long holes for accommodating the copper rod 3 are configured as an internal space of the quartz tube 23 as a dielectric cylindrical tube. The space 7 inside the long chamber is composed of gaps between the bundled quartz tubes 23.

  The quartz block 4 in the first embodiment needs to be formed with a large number of elongated holes in the longitudinal direction, and thus becomes a relatively expensive part. However, the cylindrical quartz tube 23 is mass-produced. Therefore, an inexpensive plasma processing apparatus can be realized by bundling them to form a long chamber.

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

  FIG. 5 shows the configuration of the plasma processing apparatus according to Embodiment 4 of the present invention, which is a cross-sectional view of the inductively coupled plasma torch unit cut along a plane perpendicular to the longitudinal direction, and corresponds to FIG. To do.

  In FIG. 5, the width of the long chamber in the direction perpendicular to the longitudinal direction is wider than the width in the direction perpendicular to the longitudinal direction of the plasma jet outlet 8.

  With such a configuration, stable plasma processing can be realized by securing a sufficient discharge space.

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

  FIG. 6 shows the configuration of the plasma processing apparatus according to Embodiment 5 of the present invention, which is a cross-sectional view of the inductively coupled plasma torch unit cut along a plane perpendicular to the longitudinal direction, and corresponds to FIG. To do.

  In FIG. 6, the width of the opening provided in the lowermost part of the brass block 5 is configured to be wider than the width of the opening of the quartz block 4 constituting the plasma jet port 8. In such a configuration, since the high frequency electromagnetic field generated by the copper rod 3 promotes plasma excitation further downward, the plasma ejection intensity is increased, and higher temperature plasma can be applied to the substrate.

(Embodiment 6)
Embodiment 6 of the present invention will be described below with reference to FIG.

  FIG. 7 shows the configuration of the plasma processing apparatus according to Embodiment 6 of the present invention, which is a cross-sectional view taken along a plane perpendicular to the longitudinal direction of the inductively coupled plasma torch unit, and corresponds to FIG. To do.

  In FIG. 7, the width of the opening provided at the lowermost portion of the brass block 5 is configured to be wider than the width of the opening of the quartz block 4 constituting the plasma jet port 8. In the first embodiment, the widths are almost equal. Since the concentration of the inert gas such as Ar is increased in the space between the torch unit and the base material, the configuration of the first embodiment is configured so that the lowermost portion of the brass block 5 shields the high frequency electromagnetic field. It was effective in suppressing plasma excitation. On the other hand, in this embodiment, in order to suppress plasma excitation in this space, the shield gas is jetted from the shield gas supply pipe provided in the brass block 5 to the vicinity of the plasma jet port 8.

In other words, an inert gas such as Ar is supplied to the space 7 inside the long chamber to generate plasma, while an inert gas such as N ₂ having a high discharge start voltage at atmospheric pressure is used as a shielding gas. In the vicinity of the outlet 8, the long plasma to be ejected is supplied so as to be sandwiched from the direction perpendicular to the long direction, and the plasma is shaped into a long shape. The shield gas outlet may be a slit-like gas outlet parallel to the plasma outlet 8 or may be a number of hole-like gas outlets arranged in parallel to the plasma outlet 8.

(Embodiment 7)
The seventh embodiment of the present invention will be described below with reference to FIG.

  FIG. 8 shows the configuration of the plasma processing apparatus according to Embodiment 7 of the present invention, which is a cross-sectional view of the inductively coupled plasma torch unit cut along a plane perpendicular to the longitudinal direction, and corresponds to FIG. To do.

  In FIG. 8, the copper rod insertion hole 12 has a larger diameter of the circle that makes its cross section than the holes constituting the other cooling water pipes 15, and a plurality of copper rods 3 are accommodated in one copper rod insertion hole 12. ing. Such a configuration is effective for reducing the number of long holes formed in the quartz block 4.

  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.

  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, the protective layer of the plasma display panel is cleaned and degassed, the surface of the dielectric layer consisting of an aggregate of silica particles is flattened and degassed, various electronic devices are reflowed, and the solid impurity source is reduced. It can be applied to various surface treatments such as plasma doping. 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 plasma gas supply pipe 10 may be surrounded by a grounded conductor. When the plasma gas supply pipe 10 is made of a dielectric, a high frequency electromagnetic field is irradiated inside the pipe, and an undesirable discharge may occur inside the pipe. By adopting a configuration in which the plasma gas supply pipe 10 is surrounded by a grounded conductor, such an undesirable discharge can be effectively suppressed.

  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 crystallization of a TFT semiconductor film and modification of a solar cell semiconductor film. Of course, the present invention is intended to clean and reduce the degassing of the protective layer of the plasma display panel, planarize and reduce the degassing of the dielectric layer composed of the aggregate of silica fine particles, reflow various electronic devices, and provide a solid impurity source. In various surface treatments such as plasma doping used, it is an invention useful for treating the entire desired region of the substrate in a short time when performing high temperature heat treatment in the vicinity of the surface of the substrate uniformly for a very short time. is there.

  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 Plasma torch unit 3 Copper rod 4 Quartz block 5 Brass block 6 Brass lid 7 Space inside long chamber 8 Plasma outlet 9 Plasma gas manifold 10 Plasma gas supply pipe 11 Plasma gas supply hole 12 Copper rod insertion hole 13 Shield gas nozzle 14 Shield gas manifold 15 Cooling water piping 16 Brass block 17 Resin case 18 Cooling water manifold 19 Coupler 20 Copper plate 21 Plasma gas supply piping 22 Thin film

Claims (12)

And Ji Yanba having a space long surrounded by a dielectric, and a gas inlet for supplying gas into said space is provided in parallel with the space of the elongated, and long, surrounded by a dielectric the hole of the conductor rod provided in a bore of the long, said a high-frequency power source connected to the conductor rod, and slits shaped opening communicating with said space, is arranged opposite to the opening And inductively coupled plasma processing apparatus having a substrate mounting table for holding the substrate,
The conductor rods are composed of a plurality of wires, and the plurality of conductor rods are arranged across the space while electrically connecting the plurality of conductor rods at an end portion while the entire conductor rod constitutes a coil. And the longitudinal direction of the chamber and the longitudinal direction of the opening are arranged in parallel,
An inductively coupled plasma processing apparatus comprising 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. In any cross-section taken along a plane perpendicular to the longitudinal direction including the chamber, the distance between the conductor rod and the conductor other than the conductor rod is greater than the distance of the conductor rod and the chamber, according to claim 1, wherein Inductively coupled plasma processing apparatus. Wherein the plurality of conductive rods, the being configured to reverse phase high-frequency current flows through the conductor bar to opposite sides of the chamber, inductively coupled plasma processing apparatus according to claim 1. Wherein the plurality of conductive rods, the is configured to flow interposed therebetween opposite in phase to the conductor rod frequency current chamber, inductively coupled plasma processing apparatus according to claim 1. The inductively coupled plasma processing apparatus according to claim 1 , wherein a refrigerant flows through the elongated hole. Apart from the hole in the elongated, the dielectric of the long refrigerant passage hole and parallel elongated length to is provided, inductively coupled plasma processing apparatus according to claim 1. Hole and the front Kihiya Nakadachiryuro of the long, the front communicates with refrigerant manifold respectively provided in the longitudinal direction of both ends of the winding Yanba, inductively coupled plasma processing apparatus of claim 8. The dielectric, via an air layer are housed in a conductive case that is grounded, inductively coupled plasma processing apparatus according to claim 1. The inductively coupled plasma processing apparatus according to claim 1 , wherein the elongated hole is formed of a dielectric cylindrical tube. Before Kichi Yanba consists gap plurality of bundled dielectric cylinder made of tube, inductively coupled plasma processing apparatus of claim 11, wherein. Before direction perpendicular to the longitudinal direction of the width of Kichi Yanba, said wider than direction perpendicular to the longitudinal direction of the width of the opening, inductively coupled plasma processing apparatus according to claim 1. While supplying gas into the switch Yanba having a space long surrounded by a dielectric, the ejecting gas toward the substrate from the space and the slits shaped opening which communicates, surrounded by the dielectric In an inductively coupled plasma processing method for generating a high-frequency electromagnetic field in the chamber by supplying high-frequency power to a coil made of a conductive rod provided in a long hole ,
The conductor rods are composed of a plurality of wires, and the plurality of conductor rods are arranged across the space while electrically connecting the plurality of conductor rods at an end portion while the entire conductor rod constitutes a coil. And the longitudinal direction of the chamber and the longitudinal direction of the opening are arranged in parallel,
Treating the surface of the substrate while relatively moving the chamber and the substrate mounting table in a direction perpendicular to the longitudinal direction of the opening;
An inductively coupled plasma processing method.

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