JP2006344998A - Inductive coupling plasma treatment apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inductive coupling plasma processing apparatus capable of executing uniform plasma treatment with higher dense plasma without causing deterioration of plasma density due to capacitive coupling components and ununiformity of plasma density due to deviation of an electric field distribution with respect to a large substrate. <P>SOLUTION: In the plasma treatment apparatus, inductive coupling plasma is formed in a treatment chamber 4 by supplying high-frequency power to a high-frequency antenna 13, thereby applying plasma treatment to a substrate G. In this apparatus, the high-frequency antenna 13 has a portion 63 where the presence density of antenna lines 46, 47, 48, 49, 50, 51 and 52 is not dense and portions 61, 62 where the density is dense, and is configured so that the antenna lines are not provided in its center portion 60. The entire antenna is spaced from a dielectric wall 2 to such a degree that the capacitive coupling between the high-frequency antenna 13 and the plasma decreases to a desired value. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an inductively coupled plasma processing apparatus that performs processing such as etching on a substrate.

  In a manufacturing process of a liquid crystal display (LCD) or the like, various plasma processing apparatuses such as a plasma etching apparatus and a plasma CVD film forming apparatus are used to perform a predetermined process on a glass substrate. Conventionally, a capacitively coupled plasma processing apparatus has been widely used as such a plasma processing apparatus. Recently, however, an inductively coupled plasma (Inductively Coupled Plasma) having a great advantage that a high-density plasma can be obtained at a high vacuum degree. : ICP) processing devices are attracting attention.

  The inductively coupled plasma processing apparatus arranges a high frequency antenna outside a dielectric window of a processing container that accommodates a substrate to be processed, supplies a processing gas into the processing container and supplies high frequency power to the high frequency antenna. Inductively coupled plasma is generated in the processing vessel, and a predetermined plasma process is performed on the substrate to be processed by the inductively coupled plasma. As a high-frequency antenna for an inductively coupled plasma processing apparatus, a spiral planar antenna is frequently used.

  By the way, recently, the LCD glass substrate has been increased in size, so that the inductively coupled plasma processing apparatus has to be increased in size, and the high-frequency antenna has also been increased in size accordingly.

  However, if the spiral high-frequency antenna is enlarged as it is, the antenna length becomes long, the antenna impedance becomes high, the high-frequency power supplied to the high-frequency antenna becomes difficult to match, and the antenna potential becomes high. . When the antenna potential is increased, capacitive coupling between the high-frequency antenna and the plasma is strengthened, so that inductively coupled plasma cannot be formed effectively, and the electric field distribution is biased, resulting in non-uniform plasma density and processing. The problem of non-uniformity occurs.

  As a technique for reducing the antenna impedance, a technique is known in which a high-frequency antenna is multiplexed in a plane to reduce inductance (Patent Document 1, etc.).

However, since the conventional multiplexing antenna has a branching portion in the center, when the multiplexing progresses, the branching portion becomes flat, the capacitive coupling component increases, and a sufficient plasma density cannot be obtained. However, when the substrate is enlarged, there is a limit to the effect of preventing the bias of the electric field distribution due to the multiplexing of the antennas. For this reason, it is strongly desired to realize a uniform plasma process with a higher density plasma by further reducing the capacitive coupling component and further improving the non-uniformity of the process due to the bias of the electric field distribution.
JP-A-8-83696

  The present invention has been made in view of such circumstances, and it is possible to achieve a higher density plasma without causing a decrease in plasma density due to capacitive coupling components and nonuniformity of plasma density due to bias of electric field distribution with respect to a large substrate. An object of the present invention is to provide an inductively coupled plasma processing apparatus capable of performing uniform plasma processing.

  In order to solve the above problems, the present invention provides a processing chamber that accommodates a substrate to be processed and performs plasma processing, a substrate mounting table on which the substrate to be processed is mounted, and a processing gas in the processing chamber. A processing gas supply system for supplying gas, an exhaust system for exhausting the processing chamber, a dielectric wall constituting the upper wall of the processing chamber, and an antenna wire at a portion corresponding to the dielectric wall outside the processing chamber A high-frequency antenna for forming an induction electric field in the processing chamber by being supplied with a predetermined high-frequency power, and a high-frequency power source from a high-frequency power source near the center of the high-frequency antenna A power supply member for supplying power, and plasma processing is performed on the substrate to be processed by forming inductively coupled plasma in the processing chamber by supplying high frequency power to the high frequency antenna The high-frequency antenna has a portion where the density of the antenna wire is sparse and a portion where the antenna wire is sparse, and is configured such that no antenna wire exists in the center portion thereof. There is provided an inductively coupled plasma processing apparatus characterized in that all of them are separated from the dielectric wall to such an extent that capacitive coupling between plasmas is reduced to a desired value.

  As described above, the high-frequency antenna has a portion where the density of the antenna wire is sparse and a portion where the antenna wire is sparse, so that the induction electric field can be made uniform (the uneven distribution of the induction electric field can be eliminated) and uniform plasma can be generated. In addition, since the antenna line does not exist in the central portion corresponding to the power feeding portion, the capacitive coupling between the antenna and the plasma can be reduced even if the substrate is large, and the decrease in plasma density can be suppressed. Also, capacitive coupling between the high frequency antenna and the plasma can be reduced by appropriately separating the entire high frequency antenna from the dielectric wall.

  In the inductively coupled plasma processing apparatus, it is preferable that the high-frequency antenna is multiplexed with a plurality of the antenna wires branched from the feeding member. By multiplexing in this way, the inductance can be reduced, the antenna impedance can be lowered, the antenna potential can be lowered, the unevenness of the electric field distribution can be more effectively eliminated, and the capacitive coupling can be reduced. It can be made difficult to occur. Such an effect can be made extremely high by making the number of antenna wires eight and making it eight.

  It is preferable that one or more capacitors are interposed in series on the antenna line. As a result, the antenna impedance can be lowered and the antenna potential can be lowered. Further, in a multiplexed antenna, by interposing one or a plurality of capacitors in series in any of the plurality of antenna lines, the effect of reducing the antenna impedance due to the synergistic action with the multiplexing can be further enhanced. it can.

  In the high-frequency antenna, the distance from the dielectric wall may be greater in the center portion than in the peripheral portion. As a result, the capacitive coupling component can be effectively reduced by separating the vicinity of the feeding portion having the highest potential of the antenna from the dielectric wall. In this case, the peripheral portion of the antenna may be brought into contact with the dielectric wall, and only the central portion may be separated from the dielectric wall.

  According to the present invention, a high-frequency antenna arranged substantially in a plane has a portion where the density of antenna wires is sparse and a portion where it is dense, and there is no antenna wire in the central portion corresponding to the feeding portion. In addition, since the capacitive coupling component does not increase by appropriately separating all of the high frequency antennas from the dielectric wall, the plasma density is reduced and the electric field distribution is biased by the capacitive coupling component even for large substrates. Therefore, a uniform plasma treatment can be performed with a higher density plasma without causing a non-uniform plasma density.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a sectional view showing an inductively coupled plasma etching apparatus according to an embodiment of the present invention. This apparatus is used for etching a metal film, an ITO film, an oxide film or the like when forming a thin film transistor on an LCD glass substrate in the manufacture of an LCD, for example.

This plasma etching 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).

  The shower casing 11 is made of a conductive material, preferably a metal, for example, aluminum whose inner 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 thereof, 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 supply 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

  In the antenna chamber 3, a radio frequency (RF) antenna 13 is disposed on the dielectric wall 2 so as to face the dielectric wall 2. The high frequency antenna 13 is separated from the dielectric wall 2 within a range of 50 mm or less by a spacer 13a made of an insulating member. Near the central portion of the antenna chamber 3, four feed members 16 extending vertically are provided, and a high frequency power source 15 is connected to the feed members 16 via a matching unit 14. The power supply member 16 is provided around the gas supply pipe 20a. Details of the high-frequency antenna 13 will be described later.

  During the plasma processing, the high frequency power supply 15 supplies, for example, high frequency power having a frequency of 13.56 MHz for forming an induction electric field to the high frequency antenna 13. In this way, an induction electric field is formed in the processing chamber 4 by the high frequency antenna 13 to which the high frequency power is supplied, and the processing gas supplied from the shower casing 11 is turned into plasma by the induction electric field. At this time, the output of the high frequency power supply 15 is appropriately set so as to have a value sufficient to generate plasma.

  A susceptor 22 as a mounting table for mounting the LCD glass substrate G is provided below the processing chamber 4 so as to face the high-frequency antenna 13 with the dielectric wall 2 interposed therebetween. The susceptor 22 is made of a conductive material, for example, aluminum whose surface is anodized. The LCD glass substrate G placed on the susceptor 22 is attracted and held on the susceptor 22 by an electrostatic chuck (not shown).

  The susceptor 22 is housed in an insulator frame 24 and is further 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 susceptor 22 is moved by the elevating mechanism when the substrate G is loaded and unloaded. It is driven in the vertical direction. A bellows 26 that hermetically surrounds the support column 25 is disposed between the insulator frame 24 that accommodates the susceptor 22 and the bottom of the main body container 1. Airtightness in the 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 susceptor 22 via a matching unit 28 by a power feeding rod 25 a provided in the hollow column 25. The high frequency power source 29 applies high frequency power for bias, for example, high frequency power having a frequency of 6 MHz to the susceptor 22 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 order to control the temperature of the substrate G, 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 the susceptor 22 (none is 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 or the like is connected to the bottom of the processing chamber 4 via an exhaust pipe 31. The exhaust device 30 exhausts the processing chamber 4, and the inside of the processing chamber 4 is predetermined during plasma processing. The vacuum atmosphere (for example, 1.33 Pa) is set and maintained.

Next, a detailed configuration of the high frequency antenna 13 will be described.
FIG. 2 is a plan view showing the high-frequency antenna 13. As shown in FIG. 2, the high-frequency antenna 13 is an eight-fold antenna having a square outer shape. Hereinafter, for convenience, the high frequency antenna 13 will be described using an XY coordinate system in which the center of the high frequency antenna 13 is the origin O.

  The high-frequency antenna 13 has four power feeding portions 41, 42, 43, 44 connected to the power feeding member 16 at substantially the same radial position and shifted by about 90 ° from the center around the center portion, Two antenna wires extend outward from each power feeding portion. Specifically, two antenna lines 45 and 46 extend from the power feeding part 41, antenna lines 47 and 48 extend from the power feeding part 42, and antenna lines 49 and 50 extend from the power feeding part 43. The antenna wires 51 and 52 extend from the power feeding unit 44. Then, the two antenna lines extending from each power feeding unit are provided close to each other in parallel.

  The antenna lines 45 and 46 extending from the power feeding part 41 are respectively connected to the first straight line parts 45a and 46a extending from the power feeding part 41 to the middle position of the antenna periphery in the negative Y-axis direction, and the terminal position of the first straight line part. The second straight line portions 45b and 46b that bend 90 ° inward and extend to an intermediate position up to the antenna periphery, and the antenna peripheral portion bent at an angle of approximately 45 ° obliquely outward at the terminal position of the second straight line portion Third straight portions 45c, 46c extending to the end, and fourth straight portions 45d, 46d bent at the end positions of the third straight portions 45c, 46c and extending substantially parallel to the first straight portions 45a, 46a, have. Further, the inner antenna line 46 has a fifth straight part 46e bent inward by 90 ° at the terminal position of the fourth straight part 46d so as to have the same length as the outer antenna line 45. The antenna wire 45 is grounded via the capacitor 18 connected in series at the end of the fourth straight portion 45d, and the antenna wire 46 connects the capacitor 18 connected in series at the end of the fifth straight portion 46e. Is grounded.

  The antenna lines 47 and 48 extending from the power feeding part 42 adjacent to the power feeding part 41 in the clockwise direction are respectively shifted by 90 ° from the direction of the first straight parts 45a and 46a of the antenna lines 45 and 46, that is, X. First linear portions 47a and 48a extending from the feeding portion 42 to the intermediate position on the periphery of the antenna in the negative axial direction, and bent to 90 ° inward at the terminal position of the first linear portion, to the intermediate position to the periphery of the antenna Second linear portions 47b and 48b extending; third linear portions 47c and 48c extending to the antenna peripheral edge by bending obliquely outward at an angle of approximately 45 ° at the terminal position of the second linear portion; The first straight portions 47d and 48d are bent at the end positions of the straight portions 47c and 48c and extend substantially parallel to the first straight portions 47a and 48a. Further, the inner antenna line 48 has a fifth straight part 48e bent inward by 90 ° at the terminal position of the fourth straight part 48d so as to have the same length as the outer antenna line 47. The antenna line 47 is grounded via a capacitor 18 connected in series at the end of the fourth straight part 47d, and the antenna line 48 connects the capacitor 18 connected in series at the end of the fifth straight part 48e. Is grounded.

  The antenna lines 49 and 50 extending from the power feeding part 43 adjacent to the power feeding part 42 in the clockwise direction are respectively shifted by 90 ° from the direction of the first straight parts 47a and 48a of the antenna lines 47 and 48, that is, Y. First linear portions 49a and 50a extending from the feeding portion 43 to the middle position of the antenna periphery toward the axial positive direction, and bent to 90 ° inward at the terminal position of the first straight portion, to the intermediate position to the antenna periphery A second straight line portion 49b, 50b extending, a third straight line portion 49c, 50c extending obliquely outward at an angle of approximately 45 ° at the terminal position of the second straight line portion and extending to the peripheral edge portion of the antenna, There are fourth straight portions 49d and 50d which are bent at the end positions of the straight portions 49c and 50c and extend substantially parallel to the first straight portions 49a and 50a. Further, the inner antenna line 50 has a fifth straight part 50e bent inward by 90 ° at the terminal position of the fourth straight part 50d so as to have the same length as the outer antenna line 49. The antenna line 49 is grounded via a capacitor 18 connected in series at the end of the fourth straight line portion 49d, and the antenna line 50 is connected to the capacitor 18 connected in series at the end of the fifth straight line portion 50e. Is grounded.

  The antenna lines 51 and 52 extending from the power feeding unit 44 adjacent to the power feeding unit 43 in the clockwise direction are respectively shifted by 90 ° from the direction of the first straight portions 49a and 50a of the antenna lines 49 and 50, that is, X. First linear portions 51a and 52a extending from the power feeding portion 44 to the middle position of the antenna periphery toward the axial positive direction, and bent to 90 ° inward at the terminal position of the first straight portion, to an intermediate position to the antenna periphery A second straight line portion 51b, 52b that extends, a third straight line portion 51c, 52c that bends obliquely outward at an angle of approximately 45 ° at the terminal position of the second straight line portion and extends to the peripheral edge of the antenna, The first straight portions 51d and 52d are bent at the terminal positions of the straight portions 51c and 52c and extend substantially parallel to the first straight portions 51a and 52a. Further, the inner antenna line 52 has a fifth straight part 52e bent inward by 90 ° at the terminal position of the fourth straight part 52d so as to have the same length as the outer antenna line 51. The antenna line 51 is grounded via the capacitor 18 connected in series at the end of the fourth straight part 51d, and the antenna line 52 connects the capacitor 18 connected in series at the end of the fifth straight part 52e. Is grounded.

  The first of the antenna wires 45, 46, 47, 48, 49, 50, 51, 52 is formed on the outer portion of the central portion 60 where there is no antenna wire between the four power feeding portions 41, 42, 43, 44. The antenna line in which the straight line portions 45a, 46a, 47a, 48a, 49a, 50a, 51a, 52a and the second straight line portions 45b, 46b, 47b, 48b, 49b, 50b, 51b, 52b are densely present exists. A square central portion 61 is formed, and a substantially square peripheral portion 62 is formed in which antenna lines on which the fourth straight portions 45d, 46d, 47d, 48d, 49d, 50d, 51d, and 52d are densely disposed are formed. Between the central portion 61 and the peripheral portion 62, an intermediate portion where the antenna lines on which the third straight portions 45c, 46c, 47c, 48c, 49c, 50c, 51c, and 52c are arranged sparsely exist 3 is formed.

  The antenna lines 45, 46, 47, 48, 49, 50, 51, 52 all have the same length, and the capacitors 18 connected to the respective antenna lines all have the same capacity. . Therefore, the current value flowing through each antenna line is equal.

  Next, the processing operation when the plasma etching process is performed on the LCD glass substrate G using the inductively coupled plasma etching apparatus configured as described above will be described.

  First, after the gate valve 27 is opened, the substrate G is loaded into the processing chamber 4 by a transfer mechanism (not shown), placed on the placement surface of the susceptor 22, and then an electrostatic chuck (not shown). To fix the substrate G on the susceptor 22. Next, a processing gas containing an etching gas is discharged from the processing gas supply system 20 into the processing chamber 4 into the processing chamber 4 through the gas discharge hole 12 a of the shower housing 11, and the exhaust device 30 passes through the exhaust pipe 31. By evacuating the inside of the processing chamber 4, the processing chamber is maintained in a pressure atmosphere of about 1.33 Pa, for example.

  Next, a high frequency of 13.56 MHz 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.

  In this case, as described above, the high-frequency antenna 13 forms the central part 61 and the peripheral part 62 in which the antenna lines are arranged densely, and the intermediate part 63 in which the antenna lines are arranged sparsely, and the antenna lines exist densely. Since the portion and the sparsely existing portion are configured alternately, and there is no antenna line in the central portion 60 corresponding to the feeding portion, the substrate G is a super-large one having a side of 1 m or more. However, plasma density non-uniformity due to uneven electric field distribution and plasma density reduction due to capacitive coupling components do not occur.

  The type that feeds power from the central part of the antenna wire has a tendency that the capacitance electric field strength is large in the central part of the processing vessel and small in the peripheral part. Thus, there is no antenna line in the central part, and the antenna line 3 is formed immediately below the high-frequency antenna 13 in the processing chamber 4, and the induced electric field strength is formed in the portion where the substrate G is disposed in the processing chamber 4. The distribution can be leveled to make the electric field strength distribution uniform.

  Further, since the high frequency antenna 13 has eight antenna lines branched from the power supply member and multiplexed, the inductance is reduced to 1/8 and the antenna impedance is lowered as compared with the case of one antenna line. be able to. Accordingly, the antenna potential can be effectively reduced by this, and this also makes it difficult to cause nonuniform electric field distribution and increase in capacitive coupling components.

  Furthermore, since the capacitor 18 is interposed in series at the terminal portions of the antenna lines 45, 46, 47, 48, 49, 50, 51, 52, this also reduces the antenna impedance and the antenna potential. it can.

  Furthermore, since the high frequency antenna 13 is separated from the dielectric wall 2 by the spacer 13a, this also can reduce the capacitive coupling between the high frequency antenna 13 and the plasma. The separation distance at this time can be appropriately set within a range of 50 mm or less depending on the frequency and output of the high-frequency power and the plasma density to be obtained.

  Furthermore, the antenna lines 45, 46, 47, 48, 49, 50, 51, 52 all have the same length, and the capacitors 18 connected to the antenna lines all have the same capacity. Therefore, the current values flowing through the antenna wires are equal, and the effect of uniforming the electric field strength is high. However, if eight antenna lines are configured to be composed of two pairs each having four equal lengths, four pairs of the same antenna lines are arranged 90 ° apart from each other. The arrangement of the antenna lines becomes symmetric, and the effect of uniforming the electric field strength can be obtained.

  As described above, since plasma density non-uniformity and reduction of plasma density due to capacitive coupling components are prevented, even with a very large substrate G having a side of 1 m or more, a more uniform plasma with a higher density plasma. An etching process can be performed.

  After performing the etching process as described above, the application of the high frequency power from the high frequency power supplies 15 and 29 is stopped, the pressure in the processing chamber 4 is increased to a predetermined pressure, and the gate valve 27 is opened. When the substrate G is unloaded from the processing chamber 4 to the load lock chamber (not shown) via the loading / unloading port 27a, the etching process for the substrate G is completed.

Next, another example of the high frequency antenna will be described.
FIG. 4 is a plan view showing the structure of another example of the high-frequency antenna. This high-frequency antenna 13 'has four power supply portions 41', 42 ', 43', 44 'provided in the same manner as the power supply portions 41, 42, 43, 44 of the high-frequency antenna 13 of FIG. This is a quadruple antenna in which one antenna line extends from each part. Specifically, the antenna line 45 'is fed from the power feeding part 41', the antenna line 47 'is fed from the feeding part 42', the antenna line 49 'is fed from the feeding part 43', and the antenna line 51 is fed from the feeding part 44 '. 'Extends.

  The antenna wires 45 ', 47', 49 ', 51' are respectively connected to the first straight portions 45a ', 47a', 49a ', 51a' and the second straight portions 45b ', 47b', 49b ', 51b'. , Third linear portions 45c ', 47c', 49c ', 51c' and fourth linear portions 45d ', 47d', 49d ', 51d', and these antenna lines 45 ', 47', 49 ′ And 51 ′ have the same structure and arrangement as the antenna wires 45, 47, 49, and 51 of FIG. 2 except that the capacitor 19 is interposed in the third straight portions 45c ′, 47c ′, 49c ′, and 51c ′. Have.

  Accordingly, the high-frequency antenna 13 'is similar to the high-frequency antenna 13 of FIG. 2 in that an antenna is provided at the outer portion of the central portion 60' where there is no antenna line between the four feeding portions 41 ', 42', 43 ', 44'. Antenna in which the first straight portions 45a ', 47a', 49a ', 51a' and the second straight portions 45b ', 47b', 49b'51b 'of the lines 45', 47 ', 49', 51 'are arranged A substantially square central portion 61 ′ in which the lines are densely formed is formed, and a substantially square peripheral portion 62 in which the antenna lines on which the fourth straight portions 45 d ′, 47 d ′, 49 d ′, and 51 d ′ are arranged densely exist. ′ Is formed, and an intermediate portion 63 ′ in which antenna lines on which the third straight portions 45c ′, 47c ′, 49c ′, 51c ′ are arranged sparsely exist between the central portion 61 ′ and the peripheral portion 62 ′. Is formed.

  The antenna wires 45 ', 47', 49 ', 51' all have the same length, and the terminating capacitor 18 connected to each antenna wire and the capacitor 19 provided in the third straight line portion are All of them have the same capacity, and therefore the current values flowing through the antenna lines are equal.

  As described above, the high-frequency antenna 13 'in FIG. 4 also has the central portion 61' and the peripheral portion 62 'in which the antenna wires are densely arranged, and the intermediate portion 63' in which the antenna wires are sparsely arranged, similarly to the high-frequency antenna in FIG. Formed so that the portions where the antenna lines are densely present and the portions where the antenna wires are sparsely alternated, and the antenna line does not exist in the central portion 60 ′ corresponding to the feeding portion. Even a super-large one having a side of 1 m or more does not cause nonuniformity of plasma density due to bias of electric field distribution and lowering of plasma density due to capacitive coupling components.

  Also, since the high frequency antenna 13 'has four antenna lines branched from the power supply member and multiplexed, the inductance is reduced to ¼ and the antenna impedance is reduced as compared with the case of one antenna line. Can be made. Therefore, the antenna potential can be effectively lowered, and this also makes it difficult to cause nonuniform electric field distribution and increase in capacitive coupling components.

  Capacitors 18 and 19 are interposed in series with the antenna lines 45 ', 47', 49 ', and 51' in the terminal portions and the third straight line portions, respectively, so that this also reduces the antenna impedance. The antenna potential can be lowered. Since this high frequency antenna 13 'is a quadruple antenna, the antenna impedance reduction effect is essentially small compared to the eight-fold high frequency antenna of FIG. 2, but two capacitors 18, 19 are provided for each antenna line. Since it is interposed, it is possible to obtain an antenna impedance reduction effect and an effect of lowering the antenna potential halfway, and an effect close to that of the high-frequency antenna 13 of FIG. In this case, the above effect can be further enhanced by positioning the capacitor 19 at the center of the length of each antenna line.

  The present invention can be variously modified without being limited to the above embodiment. For example, in the above embodiment, the high-frequency antenna has the pattern shown in FIG. 2, but the present invention is not limited to this, and it is only necessary that the density of the antenna line be formed so that the electric field of the substrate placement portion is uniform. For example, in the example of FIG. 2, four power feeding units are provided, but three or less or five or more may be used, and the number of antenna lines extending from each power feeding unit is not limited to one or two, but three ( The total number of antennas may be 12) or more. Further, although each antenna line is bent so as to form a square, the present invention is not limited to this, and may be bent to other shapes such as including a curve according to the substrate shape or the like. As the number of antenna lines increases, the impedance reduction effect increases. However, as multiplexing progresses, antenna lines are difficult to be arranged and capacitive coupling components tend to increase. From the viewpoint of effectively exhibiting the impedance lowering effect, an eight-fold antenna as shown in FIG. 2 is preferable.

  In the above embodiment, all the high-frequency antennas are separated from the dielectric wall by a uniform distance. However, as shown in FIG. 5, the distance from the dielectric wall is larger in the center portion than in the peripheral portion. Also good. As a result, the capacitive coupling component can be effectively reduced by separating the vicinity of the feeding portion having the highest potential of the antenna from the dielectric wall. For the same reason, only the central portion of the antenna may be separated. When the capacitive coupling component is sufficiently reduced by other measures, the high frequency antenna may not be separated from the dielectric wall.

  In the above embodiment, one or two capacitors are provided for each antenna line, but three or more capacitors may be provided. Further, the position where the capacitor is provided is not limited to the above embodiment.

  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 not only to an etching apparatus but also to other plasma processing apparatuses such as sputtering and CVD film formation. Furthermore, although the LCD substrate is used as the substrate to be processed, the present invention is not limited to this, and can be applied to processing other substrates such as a semiconductor wafer.

1 is a cross-sectional view showing an inductively coupled plasma etching apparatus according to an embodiment of the present invention. The top view which shows the structure of the high frequency antenna provided in the apparatus shown in FIG. The figure which shows the electron density distribution in the position right under the high frequency antenna of FIG. The top view which shows the structure of the other example of a high frequency antenna. Sectional drawing which shows the other arrangement | positioning state of a high frequency antenna.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1; Main body container 2; Dielectric wall 3; Antenna chamber 4; Processing chamber 13; High-frequency antenna 15; High-frequency power source 16; Feeding member 20; Processing gas supply system 22: Susceptor 30: Exhaust device 41, 42, 43, 44; Feeder 45, 46, 47, 48, 49, 50, 51, 52; antenna wire 45a, 46a, 47a, 48a, 49a, 50a, 51a, 52a; first straight line 45b, 46b, 47b, 48b, 49b , 50b, 51b, 52b; second straight part 45c, 46c, 47c, 48c, 49c, 50c, 51c, 52c; third straight part 45d, 46d, 47d, 48d, 49d, 50d, 51d, 52d; 4 straight line parts 60; central part 61; central part 62; peripheral edge part 63; middle part

Claims (6)

A processing chamber for accommodating a substrate to be processed and performing plasma processing;
A substrate mounting table on which a substrate to be processed 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 dielectric wall constituting the upper wall of the processing chamber;
An antenna wire is formed in a predetermined pattern and grounded at a portion corresponding to the dielectric wall outside the processing chamber, and an induction electric field is formed in the processing chamber by supplying a predetermined high-frequency power. A high frequency antenna,
A power supply member for supplying high-frequency power from a high-frequency power source near the center of the high-frequency antenna, and by supplying high-frequency power to the high-frequency antenna, inductively coupled plasma is formed in the processing chamber to form a substrate to be processed. A plasma processing apparatus for performing plasma processing,
The high-frequency antenna has a portion where the density of the antenna wire is sparse and a portion where the antenna wire is sparse, and is configured so that no antenna wire exists in the center portion, and capacitive coupling between the high-frequency antenna and the plasma The inductively coupled plasma processing apparatus is characterized in that all of them are separated from the dielectric wall to such an extent that the value decreases to a desired value.   2. The inductively coupled plasma processing apparatus according to claim 1, wherein the high-frequency antenna includes a plurality of the antenna wires branched from the power supply member and multiplexed.   The inductively coupled plasma processing apparatus according to claim 2, wherein the number of antenna wires is eight.   The inductively coupled plasma processing apparatus according to any one of claims 1 to 3, wherein one or more capacitors are connected in series to the antenna line.   4. The inductively coupled plasma processing apparatus according to claim 2, wherein one or a plurality of capacitors are interposed in series in each of the plurality of antenna lines.   6. The inductively coupled plasma processing apparatus according to claim 1, wherein the high-frequency antenna has a distance from the dielectric wall at a center portion larger than that at a peripheral portion.

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