JP2013077715A - Antenna unit for inductive coupling plasma, and inductive coupling plasma processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna unit for inductive coupling plasma, having highly independent current control of annular antenna portions, even when using a high frequency antenna having concentrically disposed three or more annular antennas portions.SOLUTION: In an antenna unit 50, an antenna 13 includes at least three antenna portions 13a, 13b, 13c, disposed in a concentric shape, for forming an inductive electric field in a processing chamber by supply of high frequency power. Each antenna portion is formed of antenna lines 61, 62, 63, 64, etc. wound in a spiral shape. Among antenna portions 13a, 13b, 13c, mutually adjacent antenna portions have antenna lines which are wound mutually reversely.

Description

  The present invention relates to an inductively coupled plasma antenna unit used when performing inductively coupled plasma processing on a substrate to be processed such as a glass substrate for manufacturing a flat panel display (FPD), and an inductively coupled plasma processing apparatus using the same.

  In a flat panel display (FPD) manufacturing process such as a liquid crystal display device (LCD), there is a process of performing plasma processing such as plasma etching or film formation on a glass substrate. In order to perform such plasma processing Various plasma processing apparatuses such as a plasma etching apparatus and a plasma CVD film forming apparatus are used. Conventionally, a capacitively coupled plasma processing apparatus has been widely used as a plasma processing apparatus. Recently, however, an inductively coupled plasma (ICP) has a great advantage that a high-density plasma can be obtained at a high vacuum level. Processing devices are attracting attention.

  In an inductively coupled plasma processing apparatus, a high frequency antenna is disposed above a dielectric window that forms the top wall of a processing container that accommodates a substrate to be processed, and a processing gas is supplied into the processing container and high frequency power is supplied to the high frequency antenna. By supplying, inductively coupled plasma is generated in the processing container, and a predetermined plasma process is performed on the substrate to be processed by the inductively coupled plasma. As a high-frequency antenna, a planar annular antenna having a planar predetermined pattern is frequently used.

  In an inductively coupled plasma processing apparatus using a planar annular antenna, plasma is generated in a space immediately below the planar antenna in the processing container. At this time, a high plasma density region is generated according to the electric field strength at each position immediately below the antenna. Therefore, the pattern shape of the planar annular antenna is an important factor that determines the plasma density distribution. By adjusting the density of the planar annular antenna, the induced electric field is made uniform and uniform. Is generating plasma.

  Therefore, an antenna unit having two annular antenna portions of an inner portion and an outer portion with an interval in the radial direction is provided, and these impedances are adjusted to independently control the current values of these two annular antenna portions, A technique for controlling the density distribution of the inductively coupled plasma as a whole has been proposed by controlling how the density distribution formed by diffusion of the plasma generated by each annular antenna portion is superimposed (Patent Document 1).

  However, if the length of one side of the substrate exceeds 1 m and the size is increased, the plasma diffusion effect is not sufficient in the middle part of the two annular antennas with only the two annular antenna parts of the inner part and the outer part. Density distribution control becomes difficult.

  Therefore, by providing three or more annular antenna portions concentrically and independently controlling these current values, a technology that can form uniform plasma even when the substrate size is large. Has been proposed (Patent Document 2).

Japanese Patent Laid-Open No. 2007-311182 JP 2009-277859 A

  However, when three or more annular antenna portions are provided concentrically, magnetic field overlap occurs around the antenna, and interference occurs between the annular antenna portions, so that the induction electric field of each annular antenna portion is independently controlled. It will damage the sex.

  The present invention has been made in view of such circumstances, and even when a high-frequency antenna having three or more annular antenna portions provided concentrically is used, the independent controllability of the induction electric field of the annular antenna portion is achieved. An object is to provide a high inductively coupled plasma antenna unit and an inductively coupled plasma processing apparatus using the antenna unit.

  In order to solve the above problems, a first aspect of the present invention is an inductively coupled plasma having a planar antenna that forms an inductive electric field for generating inductively coupled plasma for plasma processing a substrate in a processing chamber of a plasma processing apparatus. The antenna unit includes at least three antenna portions that are concentrically provided to form an induction electric field in the processing chamber when high-frequency power is supplied. An inductively coupled plasma antenna unit is provided in which adjacent antennas of the antenna portions are wound so that the antenna wires are wound in reverse. To do.

  In addition, a second aspect of the present invention provides a processing chamber that accommodates a rectangular substrate and performs plasma processing, a mounting table on which the rectangular substrate is mounted, and a process of supplying a processing gas into the processing chamber A gas supply system, an exhaust system for exhausting the processing chamber, and an induction for plasma processing of the substrate in the processing chamber which is disposed outside the processing chamber via a dielectric member and is supplied with high frequency power A planar antenna that forms an induction electric field that generates coupled plasma; and a high-frequency power supply unit that supplies high-frequency power to the antenna. The antenna is guided into the processing chamber by being supplied with high-frequency power. At least three antenna portions provided concentrically to form an electric field, and the antenna portion is formed by winding an antenna wire in a spiral shape; Things each other provides an inductively coupled plasma processing apparatus characterized by being wound such antenna line is Gyakumaki each other.

  In any of the above embodiments, the antenna unit constitutes a multiple antenna in which a plurality of antenna wires are wound in a spiral shape, and the plurality of antenna wires are arranged so as to be shifted by a predetermined angle in the circumferential direction. It is preferable.

  Further, the substrate is preferably rectangular, and the antenna unit is suitable for an application having a frame shape corresponding to the rectangular substrate. In this case, at least one of the antenna units is spirally formed by winding a plurality of antenna wires in the same plane so that the number of turns of the corner portion is larger than the number of turns of the central portion of the side. It can be constituted as follows. In addition, the antenna portion configured to be wound in a spiral shape so that the number of turns at the corner portion is larger than the number of turns at the central portion of the side is a frame surrounded by the outer contour line and the inner contour line. It is preferable that a bent portion is formed in each antenna line so that the region is line symmetric with respect to a center line passing through two opposing sides of the antenna portion.

  At least one of the antenna units may have a plurality of regions corresponding to different portions of the substrate, and high frequency power may be supplied independently to the plurality of regions.

  A plurality of antenna circuits including a power feeding section having a power feeding path from a matching unit connected to a high frequency power source for feeding power to the antenna sections to the antenna lines, and including the antenna sections and the power feeding sections are formed. Preferably, the antenna circuit further includes impedance control means for adjusting an impedance of at least one of the antenna circuits and thereby controlling a current value of each antenna unit. In this case, a variable capacitor provided in the power feeding path can be suitably used as the impedance control means.

  According to the present invention, the antenna unit is configured by winding the antenna wire in a spiral shape, and adjacent antenna members of the antenna unit are wound so that the antenna units are reversely wound. Therefore, for example, in the case of having three antenna portions, the intermediate antenna portion is reversely wound around the outer antenna portion and the inner antenna portion, so that a reverse induction electric field is generated in the intermediate antenna portion. The induction electric field formed by the antenna unit, the inner antenna unit, and the intermediate antenna unit can be separated to eliminate these interferences, thereby enhancing their independent controllability. Therefore, the plasma density distribution can be controlled according to various processes.

It is sectional drawing which shows the inductively coupled plasma processing apparatus which concerns on one Embodiment of this invention. It is a top view which shows an example of the antenna unit for inductively coupled plasma used for the inductively coupled plasma processing apparatus of FIG. It is a top view for demonstrating the outline of the high frequency antenna of FIG. 2, an outline, the frame area | region enclosed by them, and the bending part of an antenna line. It is a figure which shows the electric power feeding circuit of the high frequency antenna used for the inductively coupled plasma processing apparatus of FIG. The magnetic field, induced magnetic field, and plasma state (a) when a current is passed through a conventional tricyclic antenna, and the magnetic field, induced magnetic field, and plasma state (b) when a current is passed through the antenna of this embodiment. It is a schematic diagram for comparing and explaining. It is a top view which shows other embodiment of a high frequency antenna. It is a top view which shows the 1st part used for the antenna part of the high frequency antenna of FIG. It is a top view which shows the 2nd part used for the antenna part of the high frequency antenna of FIG. It is a figure which shows the further another example of an antenna part.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a sectional view showing an inductively coupled plasma processing apparatus according to an embodiment of the present invention, and FIG. 2 is a plan view showing an antenna unit used in the inductively coupled plasma processing apparatus. This apparatus is used, for example, for etching a metal film, an ITO film, an oxide film, or the like when forming a thin film transistor on an FPD glass substrate, or for ashing a resist film. Examples of the FPD include a liquid crystal display, an electro luminescence (EL) display, and a plasma display panel (PDP).

This plasma processing apparatus has a rectangular tube-shaped airtight main body container 1 made of a conductive material, for example, aluminum whose inner wall surface is anodized. The main body container 1 is assembled so as to be disassembled, and is grounded by a ground wire 1a. The main body container 1 is divided into an antenna chamber 3 and a processing chamber 4 by a dielectric wall 2 in the vertical direction. Therefore, the dielectric wall 2 constitutes the ceiling wall of the processing chamber 4. The dielectric wall 2 is made of ceramics such as Al ₂ O ₃ , quartz, or the like.

  A shower casing 11 for supplying a processing gas is fitted into the lower portion of the dielectric wall 2. The shower casing 11 is provided in a cross shape and has a structure that supports the dielectric wall 2 from below. The shower housing 11 that supports the dielectric wall 2 is suspended from the ceiling of the main body container 1 by a plurality of suspenders (not shown).

  This shower casing 11 is made of a conductive material, preferably a metal, for example, aluminum whose inner surface or outer surface is anodized so as not to generate contaminants. The shower casing 11 is formed with a gas channel 12 extending horizontally, and a plurality of gas discharge holes 12 a extending downward are communicated with the gas channel 12. On the other hand, a gas supply pipe 20 a is provided at the center of the upper surface of the dielectric wall 2 so as to communicate with the gas flow path 12. The gas supply pipe 20a penetrates from the ceiling of the main body container 1 to the outside and is connected to a processing gas supply system 20 including a processing gas supply source and a valve system. Therefore, in the plasma processing, the processing gas supplied from the processing gas supply system 20 is supplied into the shower housing 11 through the gas supply pipe 20a and discharged into the processing chamber 4 from the gas discharge hole 12a on the lower surface thereof. The

  A support shelf 5 protruding inward is provided between the side wall 3 a of the antenna chamber 3 and the side wall 4 a of the processing chamber 4 in the main body container 1, and the dielectric wall 2 is placed on the support shelf 5. The

  An antenna unit 50 including a radio frequency (RF) antenna 13 is disposed in the antenna chamber 3. The high frequency antenna 13 is connected to a high frequency power supply 15 through a matching unit 14. The high frequency antenna 13 is separated from the dielectric wall 2 by a spacer 17 made of an insulating member. Then, a high frequency power having a frequency of 13.56 MHz, for example, is supplied to the high frequency antenna 13 from the high frequency power supply 15, whereby an induction electric field is formed in the processing chamber 4, and the induction electric field is supplied from the shower casing 11. The processing gas is turned into plasma. The antenna unit 50 will be described later.

  Below the inside of the processing chamber 4, there is a mounting table 23 for mounting a rectangular FPD glass substrate (hereinafter simply referred to as a substrate) G so as to face the high-frequency antenna 13 with the dielectric wall 2 interposed therebetween. Is provided. The mounting table 23 is made of a conductive material, for example, aluminum whose surface is anodized. The substrate G mounted on the mounting table 23 is attracted and held by an electrostatic chuck (not shown).

  The mounting table 23 is housed in an insulator frame 24 and is supported by a hollow column 25. The support column 25 penetrates the bottom of the main body container 1 while maintaining an airtight state, is supported by an elevating mechanism (not shown) disposed outside the main body container 1, and the loading table 23 is moved by the elevating mechanism when the substrate G is loaded / unloaded. Is driven in the vertical direction. A bellows 26 that hermetically surrounds the support column 25 is disposed between the insulator frame 24 that houses the mounting table 23 and the bottom of the main body container 1. In addition, airtightness in the processing container 4 is guaranteed. In addition, on the side wall 4a of the processing chamber 4, a loading / unloading port 27a for loading and unloading the substrate G and a gate valve 27 for opening and closing the loading / unloading port 27a are provided.

  A high frequency power source 29 is connected to the mounting table 23 via a matching unit 28 by a power supply line 25 a provided in the hollow support column 25. The high frequency power supply 29 applies high frequency power for bias, for example, high frequency power having a frequency of 6 MHz to the mounting table 23 during plasma processing. The ions in the plasma generated in the processing chamber 4 are effectively drawn into the substrate G by the high frequency power for bias.

  Further, in the mounting table 23, a temperature control mechanism including a heating means such as a ceramic heater, a refrigerant flow path, and the like, and a temperature sensor are provided in order to control the temperature of the substrate G (both not shown). ). Piping and wiring for these mechanisms and members are all led out of the main body container 1 through the hollow support column 25.

  An exhaust device 30 including a vacuum pump and the like is connected to the bottom of the processing chamber 4 through an exhaust pipe 31. The exhaust chamber 30 exhausts the processing chamber 4, and the inside of the processing chamber 4 is set and maintained in a predetermined vacuum atmosphere (for example, 1.33 Pa) during the plasma processing.

  A cooling space (not shown) is formed on the back side of the substrate G mounted on the mounting table 23, and a He gas flow path 41 for supplying He gas as a heat transfer gas with a constant pressure is formed. Is provided. By supplying the heat transfer gas to the back side of the substrate G in this way, it is possible to avoid a temperature rise or temperature change of the substrate G under vacuum.

  Each component of the plasma processing apparatus is connected to and controlled by a control unit 100 including a microprocessor (computer). Connected to the control unit 100 is a user interface 101 including a keyboard for performing an input operation such as command input for managing the plasma processing apparatus by an operator, a display for visualizing and displaying the operating status of the plasma processing apparatus, and the like. Has been. Further, the control unit 100 causes each component of the plasma processing apparatus to execute processing according to a control program for realizing various processings executed by the plasma processing apparatus under the control of the control unit 100 and processing conditions. A storage unit 102 that stores a program for processing, that is, a processing recipe, is connected. The processing recipe is stored in a storage medium in the storage unit 102. The storage medium may be a hard disk or semiconductor memory built in the computer, or may be portable such as a CDROM, DVD, or flash memory. Moreover, you may make it transmit a recipe suitably from another apparatus via a dedicated line, for example. Then, if desired, an arbitrary processing recipe is called from the storage unit 102 by an instruction from the user interface 101 and is executed by the control unit 100, so that the desired processing in the plasma processing apparatus is performed under the control of the control unit 100. Is performed.

Next, the antenna unit 50 will be described in detail.
The antenna unit 50 includes the high-frequency antenna 13 as described above, and further includes a power feeding unit 51 that feeds the high-frequency power that has passed through the matching unit 14 to the high-frequency antenna 13.

  As shown in FIG. 2, the high-frequency antenna 13 includes an outer antenna portion 13a that is an annular antenna portion disposed at an outer portion, an inner antenna portion 13b that is an annular antenna disposed at an inner portion, and an intermediate portion therebetween. This is a three-ring antenna that is configured by being arranged concentrically with an intermediate antenna portion 13c that is a ring-shaped antenna portion. The outer antenna portion 13a, the inner antenna portion 13b, and the intermediate antenna portion 13c are all flat type having a rectangular outline, and the arrangement area of the antenna lines arranged facing the substrate has a frame shape. Yes.

  The outer antenna portion 13a, the inner antenna portion 13b, and the intermediate antenna portion 13c constitute a multiplex (quadruple) antenna in which four antenna wires are wound so as to form a spiral shape. The winding direction of the outer antenna portion 13a and the inner antenna portion 13b is the same, and the intermediate antenna portion 13c is reversed. That is, the winding direction of the antenna wire is configured to be opposite between adjacent antenna portions.

  The outer antenna portion 13a has four antenna wires 61, 62, 63, 64, and these antenna wires 61, 62, 63, 64 are wound at 90 ° positions so that the antenna wire arrangement area is It has a substantially frame shape, and the number of turns at the corner where the plasma tends to become weaker is made larger than the number of turns at the center of the side. In the illustrated example, the number of turns at the corner is 3, and the number of turns at the center of the side is 2. Further, as shown in FIG. 3, a frame region 67, which is an antenna line arrangement region indicated by diagonal lines, surrounded by the outer line 65 and the inner line 66 of the outer antenna portion 13 a is opposed to the rectangular substrate G. Therefore, a crank portion (bending portion) 68 is formed on each antenna line so as to be line symmetric (mirror symmetry) with respect to a center line passing through two opposing sides of the outer antenna 13a. Since the plasma is generated corresponding to the arrangement area of the antenna line, the plasma generated by the outer antenna portion 13a can also be directly opposed to the substrate G by causing the frame region 67 to face the substrate G as described above. .

  The inner antenna portion 13b has four antenna wires 71, 72, 73, 74, and these antenna wires 71, 72, 73, 74 are shifted in position by 90 ° and are the same as the antenna wires of the outer antenna portion 13a. The antenna wire is arranged in a direction, the antenna wire is arranged in a substantially frame shape, and the number of turns at the corner where the plasma tends to be weakened is made larger than the number of turns at the center of the side. In the illustrated example, the number of turns at the corner is 3, and the number of turns at the center of the side is 2. Further, as shown in FIG. 3, in order to make the frame region 77 indicated by the oblique lines surrounded by the outer outline 75 and the inner outline 76 of the inner antenna portion 13b face the rectangular substrate G, the two opposing sides are penetrated. Crank portions (bent portions) 78 are formed in each antenna line so as to be line symmetric (mirror symmetry) with respect to the center line. Thereby, the plasma generated by the inner antenna portion 13b can also be directly opposed to the substrate G.

  The intermediate antenna portion 13c has four antenna lines 81, 82, 83, and 84. The positions of the antenna wires 81, 82, 83, and 84 are shifted by 90 ° from each other between the outer antenna portion 13a and the inner antenna portion 13b. The antenna wire is wound in the opposite direction, the antenna wire is arranged in a substantially frame shape, and the number of turns at the corner where the plasma tends to be weakened is larger than the number of turns at the center of the side. In the illustrated example, the number of turns at the corner is 2, and the number of turns at the center of the side is 1. Further, as shown in FIG. 3, in order to directly face the frame region 87 indicated by the oblique lines surrounded by the outer outline 85 and the inner outline 86 of the intermediate antenna portion 13c with the rectangular substrate G, the two opposing sides are penetrated. Crank portions (bent portions) 88 are formed in each antenna line so as to be line symmetric (mirror symmetry) with respect to the center line. As a result, the plasma generated by the intermediate antenna portion 13c can also face the substrate G.

  The antenna chamber 3 includes four first power supply members 16a that supply power to the outer antenna portion 13a, four second power supply members 16b that supply power to the inner antenna portion 13b, and four first power supply members that supply power to the intermediate antenna portion 13c. Three power feeding members 16c (only one is shown in FIG. 1) are provided. The lower ends of the first power feeding members 16a are connected to the terminals 22a of the outer antenna portion 13a, and the lower ends of the second power feeding members 16b are It is connected to the terminal 22b of the inner antenna part 13b, and the lower end of each third feeding member 16c is connected to the terminal 22c of the intermediate antenna part 13c. The first power supply member 16 a, the second power supply member 16 b, and the third power supply member 16 c are connected in parallel to the high frequency power supply 15 through the matching unit 14. The high-frequency power supply 15 and the matching unit 14 are connected to a feeding line 19. The feeding line 19 branches to the feeding lines 19 a, 19 b, and 19 c on the downstream side of the matching unit 14, and the feeding line 19 a has four first feeding members. 16a, the power supply line 19b is connected to the four second power supply members 16b, and the power supply line 19c is connected to the four third power supply members 16c.

  The power supply lines 19, 19 a, 19 b, 19 c, the power supply members 16 a, 16 b, 16 c and the terminals 22 a, 22 b, 22 c constitute a power supply unit 51 of the antenna unit 50.

  A variable capacitor 21a is interposed in the feeder line 19a, a variable capacitor 21c is interposed in the feeder line 19c, and a variable capacitor is not interposed in the feeder line 19b. The variable capacitor 21a and the outer antenna portion 13a constitute an outer antenna circuit, and the variable capacitor 21c and the intermediate antenna portion 13c constitute an intermediate antenna circuit. On the other hand, the inner antenna circuit includes only the inner antenna portion 13b.

  As will be described later, the impedance of the outer antenna circuit is controlled by adjusting the capacitance of the variable capacitor 21a, and the impedance of the intermediate antenna circuit is controlled by adjusting the capacitance of the variable capacitor 21c. The magnitude relationship between the currents flowing through the outer antenna circuit, the inner antenna circuit, and the intermediate antenna circuit can be adjusted. The variable capacitors 21a and 21c function as current control units for the outer antenna circuit and the intermediate antenna circuit.

The impedance control of the high frequency antenna 13 will be described with reference to FIG. FIG. 4 is a diagram illustrating a power feeding circuit of the high-frequency antenna 13. As shown in this figure, the high frequency power from the high frequency power supply 15 is supplied to the outer antenna circuit 91a, the inner antenna circuit 91b, and the intermediate antenna circuit 91c through the matching unit 14. Here, the outer antenna circuit 91a, is constituted by the outer antenna portion 13a and the variable capacitor 21a, since the intermediate antenna circuit 91c is composed of an intermediate antenna circuit 13c and the variable capacitor 21c, the impedance _{Z out} of the outer antenna circuit 91a adjusting the position of the variable capacitor 21a and can be changed by changing the capacitance, the impedance Z _middle of the intermediate antenna circuit 91c is varied by varying the capacity by adjusting the position of the variable capacitor 21c Can do. On the other hand, the inner antenna circuit 91b includes only the inner antenna portion 13b, and its impedance Z _in is fixed. At this time, the current I _out of the outer antenna circuit 91a can be changed corresponding to the change of the impedance Z _out , and the current I _middle of the intermediate antenna circuit 91c can be changed corresponding to the change of the impedance Z _middle. . The current I _in of the inner antenna circuit 91b changes according to the ratio of Z _out , Z _middle, and Z _in . Thus, the variable capacitor 21a, by changing the _{Z out} and _{Z middle} by volume adjustment of 21c, freely current _{I in} an intermediate antenna circuit 91c of a current _{I middle} of the outer antenna circuit 91a of the current _{I out} and the inner antenna circuit 91b Can be changed. The plasma density distribution can be controlled by controlling the current flowing through the outer antenna portion 13a, the current flowing through the inner antenna portion 13b, and the current flowing through the intermediate antenna portion 13c.

  Next, a processing operation when performing plasma processing, for example, plasma etching processing, on the substrate G using the inductively coupled plasma processing apparatus configured as described above will be described.

  First, the substrate G is loaded into the processing chamber 4 from the loading / unloading port 27a with the gate valve 27 opened, and is loaded on the loading surface of the loading table 23. The substrate G is fixed on the mounting table 23 (not shown). Next, the processing gas supplied from the processing gas supply system 20 into the processing chamber 4 is discharged into the processing chamber 4 from the gas discharge holes 12 a of the shower housing 11 and processed by the exhaust device 30 through the exhaust pipe 31. By evacuating the inside of the chamber 4, the inside of the processing chamber is maintained in a pressure atmosphere of about 0.66 to 26.6 Pa, for example.

  At this time, He gas is supplied to the cooling space on the back side of the substrate G as a heat transfer gas via the He gas flow path 41 in order to avoid a temperature rise or temperature change of the substrate G.

  Next, a high frequency of 13.56 MHz, for example, is applied from the high frequency power supply 15 to the high frequency antenna 13, thereby forming a uniform induction electric field in the processing chamber 4 via the dielectric wall 2. Due to the induction electric field formed in this manner, the processing gas is turned into plasma in the processing chamber 4 to generate high-density inductively coupled plasma. With this plasma, a plasma process such as a plasma etching process is performed on the substrate G.

  In this case, the high-frequency antenna 13 includes, as described above, the outer antenna portion 13a that is the annular antenna portion disposed in the outer portion, the inner antenna portion 13b that is the annular antenna portion disposed in the inner portion, and these Since it is a tri-annular antenna that is configured to be concentrically spaced from the intermediate antenna portion 13c that is an annular antenna portion disposed in the intermediate portion, the size of the glass substrate G is larger than 1 m per side. Even if it is a thing, the nonuniformity of the plasma by the fall of the plasma density between each antenna part becomes difficult to produce.

Further, the high frequency antenna 13 has a variable capacitor 21a connected to the outer antenna portion 13a to enable impedance adjustment of the outer antenna circuit 91a, and a variable capacitor 21c connected to the intermediate antenna portion 13c to allow impedance of the intermediate antenna circuit 91c. Having allow adjustment, it is possible to change the current _{I in} the middle antenna circuit 91c of a current _{I middle} of the outer antenna circuit 91a of the current _{I out} and the inner antenna circuit 91b freely. That is, by adjusting the positions of the variable capacitors 21a and 21c, it is possible to control the current flowing through the outer antenna unit 13a, the current flowing through the inner antenna unit 13b, and the current flowing through the intermediate antenna unit 13c. The inductively coupled plasma generates plasma in a space immediately below the high-frequency antenna 13, and since the plasma density at each position corresponds to the electric field strength at each position, the current flowing through the outer antenna portion 13a in this way. The plasma density distribution can be controlled by controlling the electric field strength distribution by controlling the current flowing through the inner antenna portion 13b and the current flowing through the intermediate antenna portion 13c.

  For some processes, a plasma with a uniform density distribution is not always optimal for the process. Therefore, by grasping the optimum plasma density distribution according to the process and setting the positions of the variable capacitors 21a and 21c in which the plasma density distribution can be obtained in the storage unit 102 in advance, the control unit 100 performs each process. It is possible to perform plasma processing by selecting the optimal positions of the variable capacitors 21a and 21c.

  By the way, conventionally, in such a three-ring antenna, the winding direction of the antenna wire is the same in all three antenna portions. For this reason, as shown in FIG. 5A, the magnetic field generated by the current flowing in the antenna line is in the same direction in each antenna part, and the superposition of these magnetic fields causes interference between the three antenna parts. It was found that the independent controllability of the induced electric field in the antenna part was poor. For this reason, the controllability of the plasma density distribution is deteriorated.

  On the other hand, in the present embodiment, as shown in FIG. 5B, the winding direction of the antenna wire is the same for the outer antenna portion 13a and the inner antenna portion 13b, and the intermediate antenna portion 13c is reversed. Yes. That is, it is configured such that the winding direction of the antenna wire is reversed between adjacent antenna portions. Thus, by making the winding direction of the intermediate antenna portion 13c reverse, an induced electric field in the reverse direction is generated in the intermediate antenna portion 13c, thereby causing the outer antenna portion 13a, the inner antenna portion 13b, and the intermediate antenna portion 13c to The induced electric field that is formed can be separated to eliminate these interferences and to increase their independent controllability. Therefore, the plasma density distribution can be controlled according to various processes.

  In FIG. 5, x of the antenna line indicates that the electric field is in the direction from the front to the back perpendicular to the paper surface, and ● indicates that the electric field is in the direction from the back to the front perpendicular to the paper surface. .

  Further, since the high-frequency antenna 13 has a rectangular shape corresponding to the substrate G, the plasma can be supplied to the entire rectangular substrate G. Furthermore, since each antenna part has a substantially frame shape and the number of turns of the antenna wire is increased at corners where the plasma tends to be weak, relatively high plasma density distribution uniformity can be obtained. However, when the number of turns of the antenna wire at the corner portion is increased in each antenna portion, as shown in Patent Documents 1 and 2, the antenna wire protrudes outside and inside the central portion of the side at the outermost periphery and innermost periphery, respectively. Therefore, the outer and inner lines are slanted, and the plasma generation region surrounded by them is inclined by a predetermined angle with respect to the center of the rectangular substrate G, The uniformity of plasma with respect to the substrate G may be insufficient.

  In contrast, in the present embodiment, crank portions (bending portions) 68, 78, and 88 are formed on the antenna wires of the outer antenna portion 13a, the inner antenna portion 13b, and the intermediate antenna portion 13c, respectively, so that the number of turns of the corner portion is increased. The protrusion to the outside and inside due to the increase can be eliminated, and the frame regions 67, 77, 87 of each antenna portion can be directly opposed to the rectangular substrate G, and can be directly opposed to the rectangular substrate G. The plasma in a state can be generated, and more uniform plasma treatment can be performed.

  The present invention can be variously modified without being limited to the above embodiment. For example, in the above-described embodiment, the case where three antenna portions are provided has been described. However, the present invention is not limited to this, and if the winding direction of the antenna wire is reversed between adjacent antenna portions, the size of the substrate is increased. Four or more antenna portions may be provided corresponding to the above.

  In the above embodiment, each antenna unit is a quadruple antenna in which the four antenna wires are shifted by 90 ° and wound so that the whole is spiral, but the number of antenna wires is limited to four. It may be an arbitrary number of multiple antennas, and the angle to be shifted is not limited to 90 °. Furthermore, in each antenna part, a crank part (bent part) was formed in order to make the frame area directly face the rectangular substrate, but this is a multiple antenna in which the frame area is made to face the rectangular board without forming the crank part. May be.

  Furthermore, in the above-described embodiment, each antenna unit is configured in an annular shape so that high-frequency power is integrally supplied, but the antenna unit has a plurality of regions corresponding to different portions of the substrate, High frequency power may be supplied independently to the plurality of regions. Thereby, finer plasma distribution control can be performed. For example, a rectangular plane corresponding to the rectangular substrate is formed, and a first portion and a second portion are formed by winding a plurality of antenna wires in a spiral shape. The first portion includes a plurality of antenna lines and a rectangular plane. Are formed so as to connect the four corners at positions different from the rectangular plane, and the second portion includes a plurality of antenna lines, and the central portion of the four sides of the rectangular plane. And the center part of the four sides is provided at a position different from the rectangular plane so that the first part and the second part are independently supplied with the high-frequency power. Can do.

A specific configuration will be described with reference to FIGS.
For example, as shown in FIG. 6, the outer antenna portion 13a has a rectangular (frame shape) plane corresponding to the rectangular substrate G as a whole in a portion facing the dielectric wall 2 that forms an induction electric field that contributes to plasma generation. The first portion 113a and the second portion 113b are configured and formed by winding a plurality of antenna wires in a spiral shape. The antenna line of the first portion 113a forms four corners of a rectangular plane, and is provided to connect the four corners at positions different from the rectangular plane. The antenna line of the second portion 113b forms a central portion of the four sides of the rectangular plane, and is provided so as to connect the central portions of the four sides at positions different from the rectangular plane. Yes. The power supply to the first portion 113a is performed through the four terminals 122a and the power supply line 169, and the power supply to the second portion 113b is performed through the four terminals 122b and the power supply line 179, and these terminals 122a, 122b is independently supplied with high-frequency power.

  As shown in FIG. 7, the first portion 113 a constitutes a quadruple antenna in which the four antenna wires 161, 162, 163, 164 are wound at 90 ° positions and faces the dielectric wall 2. The portions forming the four corners of the rectangular plane are plane portions 161a, 162a, 163a, 164a, and the portions between these plane portions 161a, 162a, 163a, 164a are positions different from the rectangular plane. Thus, the three-dimensional parts 161b, 162b, 163b, and 164b are retracted to positions that do not contribute to the generation of the upper plasma. As shown in FIG. 8, the second portion 113 b also constitutes a quadruple antenna in which the four antenna wires 171, 172, 173, and 174 are wound at 90 ° positions and faces the dielectric wall 2. The portions forming the central part of the four sides of the rectangular plane are plane portions 171a, 172a, 173a, 174a, and the portion between these plane portions 171a, 172a, 173a, 174a is the rectangular plane. Are three-dimensional portions 171b, 172b, 173b, 174b in a state of being retracted to positions that do not contribute to the generation of the upper plasma so as to be in different positions.

  With such a configuration, independent plasma distribution control at the corner and the side center is achieved while adopting a relatively simple multiple antenna configuration in which the four antenna wires are wound in a fixed direction as in the above embodiment. Can be realized. Also in such a configuration, a reverse induced electric field can be formed by changing the winding direction of the antenna wire.

  Furthermore, in the above embodiment, each antenna unit is composed of multiple antennas wound with a plurality of antenna wires. However, as shown in FIG. 9, one antenna wire 181 is wound in a spiral shape. Also good.

  Furthermore, the form of each antenna unit is not necessarily the same. For example, only the outer antenna portion has the configuration described with reference to FIGS. 6 to 8 above, and other portions may be ordinary multiplex antennas, the crank portion may be provided in some antenna portions, You may mix an antenna and what wound one antenna.

  Furthermore, in the above embodiment, high frequency power is distributed and supplied from one high frequency power source to each antenna unit, but a high frequency power source may be provided for each antenna unit.

  Furthermore, in the above embodiment, in order to control the current of each antenna unit, a variable capacitor is provided in the outer antenna circuit and the intermediate antenna circuit, and the inner antenna circuit uses an impedance adjustment circuit without a variable capacitor. If a variable capacitor is provided in any two of the antenna circuit, the inner antenna circuit, and the intermediate antenna circuit, current control equivalent to that in the above embodiment can be performed, and current controllability equivalent to that in the above embodiment is not achieved. Alternatively, a variable capacitor may be provided according to the required controllability of current. For example, a variable capacitor may be provided in all antenna circuits, or a variable capacitor may be provided only in one of the antenna circuits. Furthermore, although the variable capacitor is used to adjust the impedance, other impedance adjusting means such as a variable coil may be used.

  Furthermore, in the above embodiment, the ceiling portion of the processing chamber is configured with a dielectric wall, and the antenna is disposed on the top surface of the dielectric wall of the ceiling portion outside the processing chamber. A structure in which the antenna is disposed in the processing chamber may be employed as long as it can be separated from the region by a dielectric wall.

  Furthermore, although the case where the present invention is applied to an etching apparatus has been described in the above embodiment, the present invention can be applied to other plasma processing apparatuses such as CVD film formation. Furthermore, although the example which used the rectangular substrate for FPD as a board | substrate was shown, it is applicable also when processing other rectangular substrates, such as a solar cell, and is not restricted to a rectangle, For example, circular, such as a semiconductor wafer It can also be applied to a substrate.

1; Main body container 2; Dielectric wall (dielectric member)
3; Antenna room 4; Processing chamber 13; High-frequency antenna 13a; Outer antenna part 13b; Inner antenna part 13c; Intermediate antenna part 14; Matching unit 15; High-frequency power supply 16a, 16b, 16c; Feed member 19, 19a, 19b, 19c Power supply line 20; processing gas supply system 21a, 21c; variable sensor capacitor 22a, 22b, 22c; terminal 23; mounting table 30; exhaust device 50; antenna unit 51; power supply unit 61, 62, 63, 64, 71, 72 73, 74, 81, 82, 83, 84; antenna wire 67, 77, 87; frame region 68, 78, 88; crank part (bent part)
91a; outer antenna circuit 91b; inner antenna circuit 91c; intermediate antenna circuit 100; control unit 101; user interface 102; storage unit G;

Claims (16)

An inductively coupled plasma antenna unit having a planar antenna for forming an inductive electric field for generating inductively coupled plasma for plasma processing a substrate in a processing chamber of a plasma processing apparatus,
The antenna has at least three antenna portions provided concentrically to form an induction electric field in the processing chamber when high-frequency power is supplied;
The antenna unit is configured by winding an antenna wire in a spiral shape,
The inductively coupled plasma antenna unit, wherein adjacent ones of the antenna portions are wound such that the antenna wires are wound in reverse.   The antenna section constitutes a multiple antenna formed by winding a plurality of antenna wires in a spiral shape, and the plurality of antenna wires are arranged so as to be shifted by a predetermined angle in the circumferential direction. The antenna unit for inductively coupled plasma according to claim 1.   3. The inductively coupled plasma antenna unit according to claim 2, wherein the substrate has a rectangular shape, and the antenna portion has a frame shape corresponding to the rectangular substrate.   At least one of the antenna portions is configured such that a plurality of antenna wires are wound in the same plane so that the number of turns of the corner portion is larger than the number of turns of the central portion of the side, thereby forming a spiral shape as a whole. The inductively coupled plasma antenna unit according to claim 3, wherein the inductively coupled plasma antenna unit is provided.   The antenna portion that is wound so that the number of turns in the corner portion is larger than the number of turns in the central portion of the side and becomes a spiral shape as a whole has an outer frame line and a frame region surrounded by the inner line. 5. The antenna unit for inductively coupled plasma according to claim 4, wherein a bent portion is formed in each antenna line so as to be symmetric with respect to a center line passing through two opposing sides of the antenna portion.   6. At least one of the antenna units has a plurality of regions corresponding to different portions of the substrate, and high frequency power is independently supplied to the plurality of regions. The antenna unit for inductively coupled plasma according to any one of the above.   A plurality of antenna circuits including a power feeding section having a power feeding path from a matching unit connected to a high frequency power source for feeding power to the antenna sections to the antenna lines, and including the antenna sections and the power feeding sections are formed. 7. The apparatus according to claim 1, further comprising an impedance control unit that adjusts an impedance of at least one of the antenna circuits and controls a current value of each antenna unit. 8. An antenna unit for inductively coupled plasma according to 1.   The inductively coupled plasma antenna unit according to claim 7, wherein the impedance control unit includes a variable capacitor provided in the power feeding path. A processing chamber for accommodating a rectangular substrate and performing plasma processing;
A mounting table on which a rectangular substrate is mounted in the processing chamber;
A processing gas supply system for supplying a processing gas into the processing chamber;
An exhaust system for exhausting the processing chamber;
A planar antenna disposed outside the processing chamber via a dielectric member and forming an induction electric field for generating inductively coupled plasma for plasma processing of the substrate in the processing chamber by supplying high-frequency power; ,
Comprising high frequency power supply means for supplying high frequency power to the antenna,
The antenna has at least three antenna portions provided concentrically to form an induction electric field in the processing chamber when high-frequency power is supplied;
The antenna unit is configured by winding an antenna wire in a spiral shape,
The inductively coupled plasma processing apparatus is characterized in that adjacent ones of the antenna portions are wound so that the antenna wires are reversely wound.   The antenna section constitutes a multiple antenna formed by winding a plurality of antenna wires in a spiral shape, and the plurality of antenna wires are arranged so as to be shifted by a predetermined angle in the circumferential direction. The inductively coupled plasma processing apparatus according to claim 9.   The inductively coupled plasma processing apparatus according to claim 10, wherein the substrate has a rectangular shape, and the antenna unit has a frame shape corresponding to the rectangular substrate.   At least one of the antenna portions is configured such that a plurality of antenna wires are wound in the same plane so that the number of turns of the corner portion is larger than the number of turns of the central portion of the side, thereby forming a spiral shape as a whole. The inductively coupled plasma processing apparatus according to claim 11.   The antenna portion that is wound so that the number of turns in the corner portion is larger than the number of turns in the central portion of the side and becomes a spiral shape as a whole has an outer frame line and a frame region surrounded by the inner line. 13. The inductively coupled plasma processing apparatus according to claim 12, wherein a bent portion is formed in each antenna line so as to be symmetric with respect to a center line passing through two opposite sides of the antenna portion.   The at least one of the antenna units has a plurality of regions corresponding to different portions of the substrate, and high frequency power is independently supplied to the plurality of regions. The inductively coupled plasma processing apparatus according to any one of the above.   The high frequency power supply means includes a high frequency power source for supplying power to each antenna unit, a matching unit connected to the high frequency power source for impedance matching, and a power supply unit having a power supply path from the matching unit to the antenna lines. A plurality of antenna circuits including each antenna unit and each power feeding unit; and impedance control means for adjusting an impedance of at least one of the antenna circuits and controlling a current value of each antenna unit. The inductively coupled plasma processing apparatus according to any one of claims 9 to 14.   The inductively coupled plasma processing apparatus according to claim 15, wherein the impedance control unit includes a variable capacitor provided in the power feeding path.

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