JP6261220B2 - Inductively coupled plasma processing equipment - Google Patents

Description

  The present invention relates to an inductively coupled plasma processing apparatus for performing plasma processing on a substrate to be processed such as a glass substrate for manufacturing a flat panel display (FPD).

  In a flat panel display (FPD) manufacturing process such as a liquid crystal display (LCD), there is a process of performing plasma processing such as plasma etching or film formation on a glass substrate, and plasma etching is performed in order to perform such plasma processing. Various plasma processing apparatuses such as an apparatus and a plasma CVD 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 the inductively coupled plasma processing apparatus, a high frequency antenna is disposed above a dielectric window that forms the top wall of a processing chamber for accommodating a substrate to be processed, and a processing gas is supplied into the processing chamber and high frequency power is supplied to the high frequency antenna Thus, inductively coupled plasma is generated in the processing chamber, and a predetermined plasma treatment 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 planar antenna having a predetermined planar pattern is often used. As such an inductively coupled plasma processing apparatus, for example, one disclosed in Patent Document 1 is known.

  Recently, the size of the substrate to be processed has been increased. For example, in the case of a rectangular glass substrate for LCD, the length of short side × long side is changed from about 1500 mm × about 1800 mm to about 2200 mm × about 2400 mm. Furthermore, the size is remarkably increased to a size of about 2800 mm × about 3000 mm.

  As the substrate to be processed increases in size, the rectangular dielectric window that forms the top wall of the inductively coupled plasma processing apparatus also increases in size, but the dielectric material such as quartz or ceramics that forms the dielectric window Is not suitable for enlargement due to its brittleness. For this reason, for example, as described in Patent Document 2, the dielectric window is divided into four parts by a metal support beam (metal support beam) to cope with an increase in the size of the dielectric window.

  By the way, since the enlargement of the substrate to be processed is still progressing significantly, it has been studied to further increase the number of divisions of the dielectric window portion, but by linear division as described in Patent Document 2. If the dielectric window is divided into three parts per side using a technique, for example, equally divided into nine parts, if the high-frequency antenna is annular or spiral, the metal support beam that defines the central divided window becomes the high-frequency antenna. A parallel closed circuit is formed, and a back electromotive force is generated in the metal support beam, so that the plasma directly under the metal support beam is weakened.

  For this reason, in Patent Document 3, the dielectric window is divided by a radial metal support beam crossing the high frequency antenna at the center of the dielectric window so that a closed circuit parallel to the high frequency antenna is not formed on the metal support beam. Technology is disclosed.

  For example, as shown in FIG. 17, when the high-frequency antenna 413 is formed by concentrically forming three annular antennas 413 a, 413 b, and 413 c, a portion that extends radially from the center of the dielectric window 402 to the metal support beam 406. Is provided so that the metal support beam 406 does not form a closed circuit parallel to the high-frequency antenna.

Japanese Patent No. 3077709 Japanese Patent No. 3609985 JP 2012-227428 A

  However, as shown in FIG. 17, when the metal support beam 406 is formed so as to extend radially from the center of the dielectric window 402, the long side of the dielectric window 402 formed in a rectangular shape corresponding to the rectangular substrate is formed. The long side center divided piece 402a including the short side and the short side central divided piece 402b including the short side have different radial widths, and the number of turns of the antenna wire of the high frequency antenna 413 is the same. The electric field strength of the induction electric field is different from the side center divided piece 402b, and it is difficult to perform plasma processing with high uniformity.

  Such a problem does not occur when a closed circuit parallel to the high-frequency antenna is formed on the metal support beam. For example, the rectangular dielectric window 402 is similarly divided into four by a diagonal line.

  On the other hand, Patent Document 3 discloses that processing gas is supplied by using a metal support beam as a shower casing. However, in the division mode as shown in FIG. 17, gas supply may be insufficient from the metal support beam. In this case, it is necessary to separately provide a ceramic shower member in which gas discharge holes are arranged in a union jack shape at the center of the dielectric window 402. In this case, since the ceramic shower member is expensive, the cost increases. In addition, since unevenness is formed in the processing chamber, by-products are likely to adhere, and particles are likely to be generated due to peeling.

  Therefore, as shown in FIG. 18, it is conceivable to use the metal support beam 406 itself as a union jack and use it as a shower casing. However, since the metal support beam 406 is concentrated at the center of the dielectric window 402, There is a concern that the plasma density may decrease in the center of the processing chamber.

  The present invention has been made in view of such circumstances, and provides an inductively coupled plasma processing apparatus capable of performing uniform plasma processing on a large substrate to be processed using a split type dielectric window. Is an issue.

  In addition, when a split type dielectric window is used for a large substrate to be processed, the plasma density at the center may be lowered even if a metal support beam that divides the dielectric window is used as a shower casing. It is an object of the present invention to provide a non-inductively coupled plasma processing apparatus.

In order to solve the above-described problem, according to a first aspect of the present invention, there is provided an inductively coupled plasma processing apparatus for performing inductively coupled plasma processing on a rectangular substrate, wherein a processing chamber that accommodates a substrate, and a substrate in the processing chamber are provided. A high frequency antenna for generating inductively coupled plasma in a region to be disposed, and a rectangular shape disposed between the plasma generating region in which the inductively coupled plasma is generated and the high frequency antenna are provided corresponding to the substrate. And the high frequency antenna is provided to circulate in a plane corresponding to the dielectric window, the dielectric window including a first divided piece including a long side, and a short side. A second divided piece that is divided into a plurality of divided pieces by a metal support beam, and the height a from the short side of the second divided piece and the length of the first divided piece the ratio a / b between the height b of the sides, 0.8 Above 1.2 are divided so that the range, the dielectric window, a line extending in the direction of 45 ° ± 6 ° from the four corners and the first line, among the first line, each of the The metal provided along the first line and the second line when a line parallel to the long side connecting the two intersections where two of the short sides intersect is a second line An inductively coupled plasma processing apparatus is provided that is divided into the first divided piece and the second divided piece by the support beam .

In a second aspect of the present invention, there is provided an inductively coupled plasma processing apparatus for performing inductively coupled plasma processing on a rectangular substrate. A high-frequency antenna for generating plasma, and a dielectric window having a rectangular shape disposed between the plasma generation region in which the inductively coupled plasma is generated and the high-frequency antenna are provided corresponding to the substrate. The high-frequency antenna is provided to circulate in a plane corresponding to the dielectric window, and the dielectric window includes a first divided piece including a long side and a second divided piece including a short side. So as to include a height a from the short side of the second divided piece and a height b from the long side of the first divided piece. The ratio a / b is in the range of 0.8 to 1.2. Is divided as the dielectric window, the long sides and the short sides are each divided into three or more, wherein the metal support beams, absent a closed loop circuit is caused along the high frequency antenna A line extending in the direction of 45 ° ± 6 ° from the four corners of the dielectric window is defined as a first line, and two first intersections of the first lines where two of the short sides intersect are connected. , A line parallel to the long side is a second line, a pair of long sides is divided into three lines, a pair of short sides is divided into three lines, a pair of short sides is divided into three lines, and the fourth line is When the intersection of the first line, the third line, and the fourth line is a second intersection, the dielectric window extends from the second line and one of the long sides. Defined by two third lines and a portion of the first line between the first intersection and the second intersection. Two first divided pieces formed at the center of the long side, including the long side, the two fourth lines extending from one short side, and the first of the first line Two second divided pieces including the short side and formed in a central portion of the short side, which are partitioned by an intersection and a portion between the second intersection, and the third line It has four third divided pieces that are partitioned by the fourth line and are formed at the corners of the dielectric window, and these divided pieces are divided by the metal support beams. An inductively coupled plasma processing apparatus is provided.

According to a third aspect of the present invention, there is provided an inductively coupled plasma processing apparatus for performing inductively coupled plasma processing on a rectangular substrate, wherein the inductive coupling is performed between a processing chamber for accommodating the substrate and a region in which the substrate is disposed in the processing chamber. A high-frequency antenna for generating plasma, a dielectric window that is disposed between a plasma generation region in which the inductively coupled plasma is generated and the high-frequency antenna, and has a rectangular shape corresponding to a substrate; A gas supply section for supplying a processing gas for forming plasma in the processing chamber, the high-frequency antenna is provided so as to circulate in a plane corresponding to the dielectric window, and the dielectric window is long. The first division of dividing into a plurality of divided pieces by a metal first support beam so as to include a first divided piece including a side and a second divided piece including a short side, and or short sides of the second divided piece The ratio a / b between the height b of the long side of the height a and the first divided piece is divided to be in the range of 0.8 to 1.2, further wherein the plurality of split At least a part of the piece is divided into a second part by a metal second support beam provided so as to pass through the center of the dielectric window, and the first support beam and the second support beam are A gas flow path through which the processing gas flows and a plurality of gas discharge holes for discharging the processing gas, functioning as the gas supply unit, and the dielectric window in a direction of 45 ° ± 6 ° from its four corners When the extending line is the first line and the line parallel to the long side connecting the two intersecting points where the two of the first lines sandwich each of the short sides is the second line, The first support beam is provided along the first line and the second line, and the first support beam is formed by the first support beam. Providing an inductively coupled plasma processing apparatus characterized by being divided piece to the second divided piece.

  According to a fourth aspect of the present invention, there is provided an inductively coupled plasma processing apparatus for performing inductively coupled plasma processing on a rectangular substrate, wherein the substrate is inductively coupled to a processing chamber containing the substrate and a region where the substrate is disposed in the processing chamber. A high-frequency antenna for generating plasma, a dielectric window that is disposed between a plasma generation region in which the inductively coupled plasma is generated and the high-frequency antenna, and has a rectangular shape corresponding to a substrate; A gas supply section for supplying a processing gas for forming plasma in the processing chamber, the high-frequency antenna is provided so as to circulate in a plane corresponding to the dielectric window, and the dielectric window is long. The first division of dividing into a plurality of divided pieces by a metal first support beam so as to include a first divided piece including a side and a second divided piece including a short side, and Is it the short side of the second segment? The ratio a / b between the height a of the first divided piece and the height b from the long side of the first divided piece is divided within a range of 0.8 to 1.2, and the plurality of divided pieces At least a part of the piece is divided into a second part by a metal second support beam provided so as to pass through the center of the dielectric window, and the dielectric window has the long side and the short side. The first support beam is divided into three or more parts, and the first support beam and the second support beam do not have a closed loop circuit generated along the high-frequency antenna, and the dielectric The long side connecting two first intersecting points where two lines sandwiching the short side of each of the first lines are defined as a first line extending from the four corners of the window in a direction of 45 ° ± 6 °. A line parallel to the second line is a second line, a pair of long sides each divided into three is a third line, When the line that divides each short side into three is the fourth line, and the intersection of the first line, the third line, and the fourth line is the second intersection, the dielectric window is The second line, the two third lines extending from one of the long sides, and the portion of the first line between the first intersection and the second intersection. , Two first divided pieces formed at a central portion of the long side, two fourth lines extending from one short side, and the first line of the first line. Two second divided pieces formed at a central portion of the short side, including the short side, and partitioned by a portion between one intersection and the second intersection; and the third A third line segment that is divided by a line and the fourth line and is formed at a corner of the dielectric window. The segment pieces are divided by the first support beam. An inductively coupled plasma processing apparatus is provided.

  In the inductively coupled plasma processing apparatus according to the third and fourth aspects, the second support beam can be provided in a cross shape passing through the center of the dielectric window.

In the inductively coupled plasma processing apparatus according to the first to fourth aspects, the high-frequency antenna is provided in a plurality of directions so as to circulate along a circumferential direction of the dielectric window within a plane corresponding to the dielectric window. The antenna portion can be arranged concentrically. Moreover, it is preferable that a high frequency of 1 MHz to 27 MHz is applied to the high frequency antenna.

According to the first and second aspects of the present invention, the dielectric window having a rectangular shape includes a first divided piece including a long side and a second divided piece including a short side. The ratio a / b between the height a from the short side of the second divided piece and the height b from the long side of the first divided piece is 0. It is divided so as to be in the range of .8 to 1.2. For this reason, uniform plasma processing can be performed on a large substrate to be processed using the split type dielectric window.

According to the third and fourth aspects of the present invention, the dielectric window having a rectangular shape includes a first divided piece including a long side and a second divided piece including a short side. The first division which is divided into a plurality of divided pieces by the first support beam made of the metal, and the height a from the short side of the second divided piece and the height width from the long side of the first divided piece The ratio a / b to b is divided so as to be in the range of 0.8 to 1.2, and at least a part of the plurality of divided pieces is provided so as to pass through the center of the dielectric window. The second division is made by the metal second support beam, and the first support beam and the second support beam have a gas flow path through which the process gas flows and a plurality of gas discharge holes for discharging the process gas. And configured to function as a gas supply unit. As described above, when the split type dielectric window is used, the first support beam does not intersect at the center of the dielectric window, so that a sufficient processing gas is supplied from the support beam. Even if the second support beam passing through is provided, it is possible to avoid a decrease in the plasma density in the central portion.

1 is a cross-sectional view schematically showing an inductively coupled plasma processing apparatus according to a first embodiment of the present invention. It is a top view which shows the dielectric material window used for the inductively coupled plasma processing apparatus of FIG. It is a top view which shows the dielectric material window and high frequency antenna which are used for the inductively coupled plasma processing apparatus of FIG. It is a schematic diagram which shows the dielectric material window divided | segmented radially. It is a figure which shows the etching distribution at the time of etching using the dielectric window divided into 8 by providing the part extended radially from a center in a metal support beam, and the high frequency antenna which goes around. It is a schematic diagram for demonstrating the division | segmentation state of the dielectric window used for the inductively coupled plasma processing apparatus of the 1st Embodiment of this invention. It is a top view which shows the other example of the dielectric material window used for the inductively coupled plasma processing apparatus of FIG. It is a top view which shows the dielectric material window and high frequency antenna of FIG. It is a top view which shows the dielectric material window used for the inductively coupled plasma processing apparatus of the 2nd Embodiment of this invention. It is a top view which shows the other example of the dielectric material window used for the inductively coupled plasma processing apparatus of the 2nd Embodiment of this invention. It is a top view which shows the other example of a high frequency antenna. (A) The figure is a top view which shows the metal window which concerns on a reference example, (B)-(D) figure is a top view which shows the example of the dielectric material window used for embodiment of this invention. It is a figure which shows the window width ratio dependence of an electric field strength ratio and an angle. FIGS. 4A to 4C are plan views showing still other examples of dielectric windows used in the inductively coupled plasma processing apparatus of FIG. FIGS. 9A to 9C are plan views showing another example of a dielectric window used in the inductively coupled plasma processing apparatus according to the second embodiment of the present invention. FIGS. 9A to 9C are plan views showing still another example of a dielectric window used in the inductively coupled plasma processing apparatus according to the second embodiment of the present invention. It is a figure which shows the conventional dielectric material window. It is a figure which shows the example which added the metal support beam which has a shower function to the conventional dielectric material window.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

<First Embodiment>
FIG. 1 is a cross-sectional view schematically showing an inductively coupled plasma processing apparatus according to the first embodiment of the present invention. The inductively coupled plasma processing apparatus shown in FIG. 1 is a plasma process such as etching of a metal film, ITO film, oxide film or the like when forming a thin film transistor on a rectangular substrate, for example, a glass substrate for FPD, or an ashing process of a resist film. Can be used. Here, as FPD, a liquid crystal display (LCD), an electroluminescence (Electro Luminescence; EL) display, a plasma display panel (PDP), etc. are illustrated. Moreover, it can use also for the plasma processing similar to the above with respect to the glass substrate for solar cell panels not only for the glass substrate for FPD.

  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 electrically grounded by a ground wire 1a. The main body container 1 is vertically divided into an antenna chamber 3 and a processing chamber 4 by a rectangular dielectric window 2 formed to be insulated from the main body container 1. The dielectric window 2 constitutes the top wall of the processing chamber 4.

  Between the side wall 3a of the antenna chamber 3 and the side wall 4a of the processing chamber 4, a metal support shelf (metal support shelf) 5 protruding inside the main body container 1 and a metal support beam (metal support beam) are provided. 6 is provided. The metal support shelf 5 and the metal support beam 6 are made of aluminum, for example. As will be described later, the dielectric window 2 is divided into a plurality of dielectric window pieces formed of a ceramic such as alumina or a dielectric such as quartz, and in the divided state, the metal support shelf 5 and the metal support beam 6 are divided. Supported by The metal support beam 6 is suspended from the ceiling of the main body container 1 by a plurality of suspenders (not shown). The metal support shelf 5 and the metal support beam 6 may be covered with a dielectric member.

  The metal support beam 6 may also serve as a shower casing for supplying a processing gas. When the metal support beam 6 also serves as a shower casing, a gas flow path 8 extending in parallel to the surface to be processed of the substrate to be processed is formed inside the metal support beam 6 as shown in the figure. In the gas flow path 8, a plurality of gas discharge holes 8 a for ejecting process gas into the process chamber 4 are formed. A processing gas is supplied to the gas flow path 8 from the processing gas supply system 20 via the gas supply pipe 20a, and the processing gas is discharged into the processing chamber 4 from the gas discharge holes 8a. Instead of being supplied from the support beam 6, or in addition to the process gas, a ceramic shower member provided separately from the dielectric window 2 may be provided to discharge the process gas.

  A high frequency antenna 13 is disposed in the antenna chamber 3 above the dielectric window 2 so as to face the dielectric window 2. The high-frequency antenna 13 is disposed away from the dielectric window 2 by a spacer 14 made of an insulating member.

  A first high frequency power supply 18 is connected to the high frequency antenna 13 through a power supply member 15, a power supply line 16, and a matching unit 17. During the plasma processing, for example, high-frequency power of 13.56 MHz is supplied to the high-frequency antenna 13 from the first high-frequency power source 18 via the matching unit 17, the feed line 16, and the feed member 15. An induction electric field is formed in the inner plasma generation region, and the processing gas supplied from the plurality of gas discharge holes 8 a is converted into plasma in the plasma generation region in the processing chamber 4 by the induction electric field.

  In order to place a rectangular FPD glass substrate (hereinafter simply referred to as a substrate) G as a substrate to be processed so as to face the high-frequency antenna 13 with the dielectric window 2 in between in the lower part of the processing chamber 4. The mounting table 23 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. However, the airtightness in the processing chamber 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 second 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 column 25. The second high frequency power supply 29 applies high frequency power for biasing, for example, high frequency power having a frequency of 3.2 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 self-bias generated by the bias high-frequency power.

  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 dielectric window 2 and the high frequency antenna 13 will be described with reference to FIGS.
FIG. 2 is a plan view showing the dielectric window, and FIG. 3 is a plan view showing the dielectric window and the high-frequency antenna.

  As shown in FIG. 2, the rectangular dielectric window 2 has a long side 2a and a short side 2b. The dielectric window 2 is divided by the metal support beam 6 into two long side divided pieces 201 including the long side 2a and two short side divided pieces 202 including the short side 2b, and the long side divided. The piece 201 and the short side divided piece 202 are divided so as to have the same radial width.

  Specifically, the dielectric window 2 has four lines extending in the direction of 45 ° from the four corners as the first lines 51, and two of the first lines 51 intersecting each other with the two short sides 2 b intersecting each other. When the line parallel to the long side connecting the intersection point P is the second line 52, the two long side side divided pieces 201 and the two short side side divided by the first line 51 and the second line 52. It is divided into pieces 202. The metal support beam 6 exists in a predetermined width including the first line 51 and the second line 52, and the long side divided piece 201 and the short side divided piece 202 are supported by the metal support beam 6. ing.

  The high-frequency antenna 13 is provided so as to circulate in the circumferential direction in the plane of the dielectric window 2, and in this example, the outer antenna portion 13a, the intermediate antenna portion 13b, and the inner antenna portion are spaced apart in the radial direction. 13c has three concentric antenna parts, and all have the same rectangular shape as the dielectric window 2 in outline. In this example, these antenna parts are formed in an annular shape.

  In the processing chamber 4, plasma is generated in a space immediately below the antenna line of the high-frequency antenna 13, and at this time, a high plasma density is obtained according to the electric field strength at each position immediately below the antenna line of the high-frequency antenna 13. Because of the distribution of the region and the low plasma density region, the high-frequency antenna 13 has three rotating antenna parts, an outer antenna part 13a, an intermediate antenna part 13b, and an inner antenna part 13c, spaced in the radial direction. By adjusting these impedances, the current value can be controlled independently, and the density distribution of the inductively coupled plasma as a whole can be controlled.

  The form of division of the dielectric window 2 and the shape of the high-frequency antenna 13 are merely examples, and various types can be used as will be described later.

  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 hole 8a of the metal support beam 6 which also serves as a shower housing, and the exhaust device 30 discharges the exhaust pipe. The inside of the processing chamber 4 is evacuated through 31 to maintain the processing chamber 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 1 MHz to 27 MHz, for example, is applied from the high frequency power supply 18 to the high frequency antenna 13, thereby generating a uniform induction electric field in the processing chamber 4 through the dielectric window 2. Due to the induction electric field generated in this way, the processing gas is turned into plasma in the processing chamber 4 and high-density inductively coupled plasma is generated. By this plasma, for example, a plasma etching process is performed on the substrate G as a plasma process.

  In this case, the size of the dielectric window 2 is increasing, and the dielectric window 2 is divided into a plurality of dielectric window pieces. At this time, if the dielectric window 2 is divided radially, the electric field strength distribution of the induction electric field is not uniform. It has been found that the uniformity of the plasma treatment becomes insufficient.

  This point will be described with reference to the schematic diagram of FIG. FIG. 4 is a schematic view showing a dielectric window divided radially. In FIG. 4, for convenience, the high-frequency antenna 13 is depicted as a two-turn annular antenna, and the metal support beam 6 is omitted. As shown in FIG. 4, when the rectangular dielectric window 2 is divided into diagonal lines, which is a typical radial division, the radial width of the long-side divided piece 201 ′ including the long side 2a (that is, the dielectric) The distance from the center of the window 2 to the long side 2a is B / 2 where B is the length of the short side 2b. On the other hand, the radial width (that is, the distance from the center of the dielectric window 2 to the short side 2b) of the short side divided piece region 202 ′ including the short side 2b is A / when the length of the long side 2a is A. 2. Accordingly, the radial width of the short-side divided piece 202 ′ is larger than the radial width of the long-side divided piece 201 ′. Here, since the number of turns of the high-frequency antenna 13 is the same in the long-side divided piece 201 ′ and the short-side divided piece 202 ′, the portion corresponding to the long-side divided piece 201 ′ is reduced by the small width in the radial direction. However, the electric field strength of the induction electric field is increased. For this reason, the portion corresponding to the long-side divided piece 201 ′ has a higher current density and stronger plasma, and the plasma uniformity is lowered.

  As described above, such a problem is that the metal support beam shown in FIG. 17 is provided with a portion extending radially from the center and divided into eight windows so as not to form a closed circuit parallel to the high-frequency antenna. This also occurs in the case of the technique described in Patent Document 3.

  When the etching process was actually performed by the plasma processing apparatus using the dielectric window and the high-frequency antenna shown in FIG. 17, the etching distribution of the substrate was as shown in FIG. FIG. 5 shows the etching rate of each part when the etching rate of the short side central part of each of the inner side and the outer side of the substrate G is 1.00. The short side central part is more than the long side central part. The etching rate was lowered.

Therefore, in the present embodiment, the rectangular dielectric window 2 is divided into the long side divided piece 201 including the long side 2a and the short side divided piece 202 including the short side 2b, and the long side divided. The piece 201 and the short side divided piece 202 are divided so that the radial widths are equal. Specifically, as shown in FIG. 2, the dielectric window 2 sandwiches the short side 2b among the four first lines 51 extending from the four corners in the direction of 45 ° and the first lines 51. A second line 52 that is parallel to the long side 2a and connects two intersecting points P where two intersect, and the first side 51 and the second line 52 allow the long side divided piece 201 and the short side to be It is divided into divided pieces 202. Therefore, as shown schematically in FIG. 6 corresponding to FIG. 4, the radial width (height from the long side 2a) of the long side divided piece 201 and the radial direction of the short side divided piece 202 The width (height from the short side 2b) is B / 2. For this reason, since the long-side divided piece 201 and the short-side divided piece 202 have the same number of turns of the high-frequency antenna 13 and the same width in the radial direction, the electric field strengths of the induction electric fields in the corresponding portions are the same. Thus, uniform plasma can be formed.

  7 and 8 show an example in which the present embodiment is applied to a dielectric window having a division mode in which a closed circuit parallel to the high-frequency antenna is not configured. FIG. 7 is a plan view showing the dielectric window, and FIG. 8 is a plan view showing the dielectric window and the high-frequency antenna. In this example, the long side 2a and the short side 2b are each divided into three, and the dielectric window 2 is divided into two long side central divisions formed in a portion corresponding to the long side center by a metal support beam 6. Eight divisions divided into a piece 203, two short side center divided pieces 204 formed in a portion corresponding to the center of the short side, and four corner divided pieces 205 including the long side end portion and the short side end portion. It is a type. The long side central divided piece 203 and the short side central divided piece 204 are divided so that the radial widths are equal. The number of divisions of the long side 2a and the short side 2b may be three or more.

  Specifically, a line extending in the direction of 45 ° from the four corners of the dielectric window 2 is defined as a first line 51, and two intersection points P where two of the first lines 51 across the short side 2b intersect each other are connected. A line parallel to the long side is referred to as a second line 52, a line dividing the pair of long sides 2a into three parts is referred to as a third line 53, and a line dividing each of the pair of short sides 2b into three parts is a fourth line 54. When the intersection of the first line 51, the third line 53, and the fourth line 54 is an intersection point Q, the dielectric window 2 extends from the second line 52 and one long side 2a. Two long side center divided pieces 203 divided by two third lines 53 and a portion between the intersection point P and the intersection point Q of the first line 51, and two second sides extending from one short side 2b The four short lines 204 divided by the four lines 54 and the portion between the intersection point P and the intersection point Q of the first line 51, and the third 53 and is divided into four corners divided side 205 which is defined by the fourth line 54. The metal support beam 6 having a predetermined width exists in the portion between the intersection point P and the intersection point Q of the second line 52, the third line 53, the fourth line 54, and the first line 51, that is, in the divided portion. These divided pieces are supported by the metal support beam 6.

  As in FIG. 3, the high-frequency antenna 13 has three concentric antenna parts, an outer antenna part 13 a, an intermediate antenna part 13 b, and an inner antenna part 13 c, all of which have the same rectangular shape as the dielectric window 2. It has a shape.

  In this example, the length in the radial direction of the long side central divided piece 203 and the length in the radial direction of the short side central divided piece 204 are both ½ of the length of the short side 2b, and both are equal. Become. Therefore, the long side central divided piece 203 and the short side central divided piece 204 have the same number of turns of the high-frequency antenna 13 and the same width in the radial direction. Thus, uniform plasma can be formed.

  Further, even if the long side 2a and the short side 2b of the dielectric window 2 are divided into three as described above, the metal support beam 6 does not form a closed circuit parallel to the high-frequency antenna 13, so that the metal support The back electromotive force is not generated in the beam 6 and the plasma immediately below the metal supporting beam 6 is not weakened.

<Second Embodiment>
Next, a second embodiment of the present invention will be described.
In the first embodiment, the metal support beam 6 of the dielectric window 2 does not necessarily have the function of a shower casing that discharges processing gas, and the metal support beam 6 has the function of a shower casing. However, in the present embodiment, the metal support beam of the first embodiment is configured as a shower housing, and an additional metal support beam is provided. In addition, it has a dielectric window configured to supply process gas only from the metal support beam.

  In the first embodiment, the metal support beam 6 is used in order to make the dielectric window 2 into a division mode in consideration of the uniformity of plasma. For this reason, even if the metal support beam 6 is used as a shower casing, the supply of the processing gas may be insufficient particularly in the portion corresponding to the center of the dielectric window 2. In such a case, conventionally, a ceramic shower member having gas discharge holes arranged in a union jack shape has been provided separately.

  However, since the ceramic shower member is expensive, the cost increases. In addition, since unevenness is formed in the processing chamber, by-products are likely to adhere, and particles are likely to be generated due to peeling.

  For this reason, in the present embodiment, as shown in FIG. 9, the metal support beam is used as a shower casing, and the dielectric shown in FIGS. In addition to the metal support beam 6 of the window 2, a dielectric window 2 'provided with a cross-shaped metal support beam 6a passing through the center is used.

  In this case, the long side divided piece 201 is further divided into the first divided piece 201a and the second divided piece 201b by the metal support beam 6a, and the short side divided piece 202 is further divided into the first divided piece 202a. And divided into second divided pieces 202b.

  FIG. 10 shows a dielectric provided with a cross-shaped metal support beam 6a passing through the center in addition to the metal support beam 6 of the dielectric window 2 shown in FIGS. 7 and 8 as another example of the first embodiment. This is an example using a body window 2 '. In the example of FIG. 10, a metal support beam 6 b is further provided along the first line 51 to connect the corner portion of the dielectric window 2 ′ from the intersection point Q.

  In the example of FIG. 10, the long side central divided piece 203 is further divided into a first divided piece 203a and a second divided piece 203b by the metal support beam 6a, and the short side central divided piece 204 is further divided into the first divided piece. It is divided into a piece 204a and a second divided piece 204b, and the corner divided piece 205 is further divided into a first divided piece 205a and a second divided piece 205b by the metal support beam 6b.

  The dielectric window 2 of the first embodiment is parallel to the long side 2a as a dividing line at the center thereof so that the radial width of the long side divided piece and the short side divided piece are the same. The metal support beam 6 is provided along the second line 52, and there is no crossing portion of the metal support beam 6 in the center. Therefore, even if a dielectric window 2 'is formed by adding a cross-shaped metal support beam 6a that passes through the center to the metal support beam 6 of the dielectric window 2, as shown in FIG. The concentration of the metal support beams does not occur, and the plasma density does not decrease at the center of the processing chamber 4. In the example of FIG. 10, since the metal support beam 6 a is provided so as to intersect the high frequency antenna 13, there is no closed loop circuit generated along the high frequency antenna 13.

  Further, by adding the metal support beams 6a and 6b in this way, the number of divisions of the dielectric window can be further increased, and it becomes easy to cope with the increase in the size of the dielectric window as the apparatus is further increased in size.

<Field strength ratio of induction field>
Next, the electric field strength ratio of the induced electric field between the second divided piece 202 including the short side 2b and the first divided piece 201 including the long side 2a will be described.

The electric field strength E of the induction electric field is proportional to the antenna current amount I and the number of turns n, and inversely proportional to the window width (radial width) d, as shown in the following equation (1).
E ∝ I × n / d (1)

  From the equation (1), the electric field strength of the induction electric field varies depending on the width of the window width d. When the window width d is increased along the radial direction, plasma must be generated more widely than when the window width d is narrow. For this reason, the electric field strength of the induction electric field E is weakened, and the plasma is weakened. On the contrary, if the window width d narrows in the radial direction, the electric field strength of the induction electric field E increases.

  For example, as shown in FIG. 12A, when the first line 51 'is diagonal, the electric field strength of the induction electric field E of the second divided piece 202' including the short side 2b is the weakest. . In the example shown in FIG. 12A, the window width ratio a / b between the window width dB (= a) of the second divided piece 202 ′ and the window width dA (= b) of the first divided piece 201 ′. Is assumed to be 1.3.

  Hereinafter, when the window width ratio a / b is reduced to 1.1 as shown in FIG. 12B, the window width dB (= a) of the second divided piece 202 becomes narrower, and the second divided piece. The electric field strength of 202 increases. Further, as shown in FIG. 12C, when the window width ratio a / b becomes 1, the electric field strength of the second divided piece 202 further increases, and the second divided piece 202 and the first divided piece 201 are further increased. The electric field strengths of both induction electric fields E are equal. Further, as shown in FIG. 12D, when the window width ratio a / b is less than 1, for example, 0.9, the electric field of the induction electric field E is generated between the second divided piece 202 and the first divided piece 201. The intensity is reversed.

The electric field strength EA of the first divided pieces 201 ′ and 201 including the long side 2a shown in FIGS.
EA = I × n / dA (2)
It is.

The electric field strength EB of the second divided pieces 202 ′ and 202 including the short side 2b is
EB = I × n / dB (3)
It is.

The ratio “EB / EA” between the electric field intensity EB of the second divided pieces 202 ′ and 202 and the electric field intensity EA of the first divided pieces 201 ′ and 201 is:
EB / EA = (I × n / dB) / (I × n / dA) (4)
It is.

Since the first divided pieces 201 ′ and 201 and the second divided pieces 202 ′ and 202 have the same amount of current I and the number of turns n of the antenna,
EB / EA = (1 / dB) / (1 / dA)
= DA / dB (5)
It becomes.

Since the window width dA is the radial window width b of the first divided pieces 201 ′ and 201, and the window width dB is the radial window width a of the second divided pieces 202 ′ and 202,
EB / EA = b / a (6)
It becomes.

  As shown in the equation (6), the electric field intensity ratio “EB / EA” of the induction electric field E is determined by the radial window width a of the first divided pieces 201 ′ and 201 and the second divided pieces 202 ′ and 202. Is inversely proportional to the window width ratio “a / b” to the window width b in the radial direction.

Table 1 is a table showing the window width a, the window width b, the window width ratio a / b, the electric field intensity ratio EB / EA, and the angle θ formed by the first line 51 ′ or 51 and the long side 2a.

FIG. 13 is a graph showing the dependence of the electric field strength ratio and angle on the window width ratio.
As shown in FIG. 13, as the value of the window width ratio a / b deviates from “1”, the value of the electric field intensity ratio EB / EA of the induced electric field deviates from “1”. This is because the induced electric field EB generated in the second divided pieces 202 ′ and 202 and the induced electric field generated in the first divided pieces 201 ′ and 201 when the window width ratio a / b deviates from “1”. It shows that the deviation from EA increases.

  In actual processing, it is effective for uniform processing that the difference between the induced electric field EB and the induced electric field EA is smaller, preferably that there is almost no difference between the induced electric field EB and the induced electric field EA. However, in practice, a certain tolerance can be expected for the deviation between the induced electric field EB and the induced electric field EA. An example of the allowable error is a range of about ± 20 to 25% from a practical viewpoint. For example, in order to suppress the deviation between the induced electric field EB and the induced electric field EA within about ± 20 to 25%, the electric field intensity ratio EB / EA of the induced electric field is suppressed to a range of about 0.8 to 1.2. Good. For this purpose, as shown in a range M1 in FIG. 13, the window width ratio a / b is set to be in the range of 0.8 to 1.2, and the first divided piece 201 and the second The divided piece 202 may be divided.

  In addition, setting the window width ratio a / b within the range of 0.8 to 1.2 means that the angle θ formed by the first line 51 and the long side 2a of the first divided piece 201 is 45 °. It is to shift from. For example, as shown in FIG. 13, the electric field of the induction electric field E can also be set by setting the angle θ so that the angle θ is within a range M2 of 45 ° to about ± 6 ° (a range of about 39 ° to about 51 °). The intensity ratio EB / EA can be suppressed to a range of about 0.8 to 1.2.

  Further, if the angle θ is set to be in the range of 45 ° to about ± 6 ° (a range of about 39 ° to about 51 °), the window width ratio a / b is 0.8 to 1.2. It can also be said that it can be set within the range.

  As described above, the window width ratio a / b is set in the range of 0.8 to 1.2, and / or the angle θ formed by the first line 51 and the long side 2a of the first divided piece 201 is set to By setting the range from 45 ° to about ± 6 ° (from about 39 ° to about 51 °), the electric field strength ratio EB / EA of the induced electric field is suppressed to a range from about 0.8 to 1.2. Thus, an inductively coupled plasma processing apparatus capable of achieving the above can be obtained.

  Further, the window width ratio a / b is set as shown in FIGS. 14A to 14C, the dielectric window 2 described with reference to FIGS. 7 and 8, and FIG. ) To (C), the dielectric window 2 'described with reference to FIG. 9, and the dielectric window 2 described with reference to FIG. 10 as shown in FIGS. 16 (A) to (C). It can also be applied to ′.

The present invention can be variously modified without being limited to the above embodiment.
For example, in the above-described embodiment, a concentric arrangement of three circulating antenna units is shown as a high-frequency antenna. However, there are four or more antenna units including only one antenna unit or two antenna units. It may be. By providing two or more antenna parts, the impedance value of each antenna part can be adjusted to control the current value independently, and the density distribution of the inductively coupled plasma as a whole can be controlled. In addition, the antenna portion constituting the high-frequency antenna has been described as an example of an annular portion. However, the antenna portion may be provided so as to circulate along the circumferential direction in the plane corresponding to the dielectric window. The shape may also be For example, a multiple spiral antenna as shown in FIG. In the example of FIG. 11, a multiplex (quadruple) antenna is configured in which four antenna wires 131, 132, 133, and 134 are wound by shifting positions by 90 ° to form a spiral shape as a whole. The arrangement area is substantially frame-shaped.

  In the above embodiment, the etching apparatus is illustrated as an example of the inductively coupled plasma processing apparatus. However, the present invention is not limited to the etching apparatus, and can be applied to the other plasma processing apparatus such as CVD film formation.

  Furthermore, although an example in which an FPD substrate is used as the substrate to be processed has been shown, a rectangular substrate can be applied to plasma processing for other substrates such as a substrate for a solar cell panel.

DESCRIPTION OF SYMBOLS 1; Main body container 2; Dielectric window 3; Antenna room 4; Processing room 5; Metal support shelf 6,6a, 6b; Metal support beam 13; High frequency antenna 13a; Outer antenna part 13b; 51; 1st line 52; 2nd line 53; 3rd line 54; 4th line 201; Long side side division piece 202; Short side side division piece 203; Long side center division piece 204; Divided piece 205; Corner divided piece G: Substrate (rectangular substrate)

Claims (7)

An inductively coupled plasma processing apparatus for performing inductively coupled plasma processing on a rectangular substrate,
A processing chamber for accommodating the substrate;
A high-frequency antenna for generating inductively coupled plasma in a region where a substrate in the processing chamber is disposed;
A dielectric window that is disposed between the plasma generation region where the inductively coupled plasma is generated and the high-frequency antenna and has a rectangular shape provided corresponding to the substrate;
The high-frequency antenna is provided so as to circulate in a plane corresponding to the dielectric window,
The dielectric window is divided into a plurality of divided pieces by a metal support beam so as to include a first divided piece including a long side and a second divided piece including a short side, and the second The ratio a / b of the height a from the short side of the divided piece to the height b from the long side of the first divided piece is divided into a range of 0.8 to 1.2. ,
The dielectric window has a line extending in the direction of 45 ° ± 6 ° from its four corners as a first line, and connects two intersections where two of the first lines sandwich the short side, respectively. When the line parallel to the long side is the second line, the first divided piece and the first line are formed by the metal supporting beam provided along the first line and the second line. The inductively coupled plasma processing apparatus is divided into two divided pieces . An inductively coupled plasma processing apparatus for performing inductively coupled plasma processing on a rectangular substrate,
A processing chamber for accommodating the substrate;
A high-frequency antenna for generating inductively coupled plasma in a region where a substrate in the processing chamber is disposed;
A dielectric window that is disposed between the plasma generation region where the inductively coupled plasma is generated and the high-frequency antenna and has a rectangular shape provided corresponding to the substrate;
The high-frequency antenna is provided so as to circulate in a plane corresponding to the dielectric window,
The dielectric window is divided into a plurality of divided pieces by a metal support beam so as to include a first divided piece including a long side and a second divided piece including a short side, and the second The ratio a / b of the height a from the short side of the divided piece to the height b from the long side of the first divided piece is divided into a range of 0.8 to 1.2. ,
In the dielectric window, the long side and the short side are each divided into three or more, and the metal support beam does not have a closed loop circuit generated along the high-frequency antenna ,
A line extending in the direction of 45 ° ± 6 ° from the four corners of the dielectric window is defined as a first line, and the first line is connected to two first intersections where two of the short sides intersect each other. The line parallel to the long side is the second line, the pair of long sides is divided into three lines, the third line is the pair of short sides, and the fourth line is the line dividing the pair of short sides is the third line. When the intersection of the first line, the third line, and the fourth line is the second intersection,
The dielectric window is
Partitioned by the second line, two third lines extending from one of the long sides, and a portion of the first line between the first intersection and the second intersection. The two first divided pieces that include the long side and are formed at the center of the long side,
Including the short side defined by two fourth lines extending from one short side and a portion between the first intersection and the second intersection of the first line, The two second divided pieces formed at the center of the short side; and
The third line and the fourth line are divided into four third divided pieces formed at corners of the dielectric window, and these divided pieces are divided by the metal support beam. inductively coupled plasma processing apparatus, wherein the being. An inductively coupled plasma processing apparatus for performing inductively coupled plasma processing on a rectangular substrate,
A processing chamber for accommodating the substrate;
A high-frequency antenna for generating inductively coupled plasma in a region where a substrate in the processing chamber is disposed;
A dielectric window disposed between the plasma generation region where the inductively coupled plasma is generated and the high-frequency antenna, and having a rectangular shape corresponding to the substrate;
A gas supply unit for supplying a processing gas for forming plasma in the processing chamber;
The high-frequency antenna is provided so as to circulate in a plane corresponding to the dielectric window,
The dielectric window is divided into a plurality of divided pieces by a metal first support beam so as to include a first divided piece including a long side and a second divided piece including a short side. The ratio a / b between the height a from the short side of the second divided piece and the height b from the long side of the first divided piece is 0.8 or more and 1.2. Divided into the following ranges,
Further, at least a part of the plurality of divided pieces is second divided by a metal second support beam provided so as to pass through the center of the dielectric window,
The first support beam and the second support beam have a gas flow path through which a processing gas flows and a plurality of gas discharge holes for discharging the processing gas, and function as the gas supply unit ,
The dielectric window has a line extending in the direction of 45 ° ± 6 ° from its four corners as a first line, and connects two intersections where two of the first lines sandwich the short side, respectively. When the line parallel to the long side is the second line, the first support beam is provided along the first line and the second line, and the first support beam causes the first The inductively coupled plasma processing apparatus is divided into one divided piece and the second divided piece . An inductively coupled plasma processing apparatus for performing inductively coupled plasma processing on a rectangular substrate,
A processing chamber for accommodating the substrate;
A high-frequency antenna for generating inductively coupled plasma in a region where a substrate in the processing chamber is disposed;
A dielectric window disposed between the plasma generation region where the inductively coupled plasma is generated and the high-frequency antenna, and having a rectangular shape corresponding to the substrate;
A gas supply unit for supplying a processing gas for forming plasma in the processing chamber;
With
The high-frequency antenna is provided so as to circulate in a plane corresponding to the dielectric window,
The dielectric window is divided into a plurality of divided pieces by a metal first support beam so as to include a first divided piece including a long side and a second divided piece including a short side. The ratio a / b between the height a from the short side of the second divided piece and the height b from the long side of the first divided piece is 0.8 or more and 1.2. Divided into the following ranges,
Further, at least a part of the plurality of divided pieces is second divided by a metal second support beam provided so as to pass through the center of the dielectric window,
In the dielectric window, the long side and the short side are respectively divided into three or more by the first support beam, and the first support beam and the second support beam include the high-frequency antenna. There is no closed-loop circuit that occurs along
A line extending in the direction of 45 ° ± 6 ° from the four corners of the dielectric window is defined as a first line, and the first line is connected to two first intersections where two of the short sides intersect each other. The line parallel to the long side is the second line, the pair of long sides is divided into three lines, the third line is the pair of short sides, and the fourth line is the line dividing the pair of short sides is the third line. When the intersection of the first line, the third line, and the fourth line is the second intersection,
The dielectric window is
Partitioned by the second line, two third lines extending from one of the long sides, and a portion of the first line between the first intersection and the second intersection. The two first divided pieces that include the long side and are formed at the center of the long side,
Including the short side defined by two fourth lines extending from one short side and a portion between the first intersection and the second intersection of the first line, The two second divided pieces formed at the center of the short side; and
The third line and the fourth line are divided into four third divided pieces formed at corners of the dielectric window, and these divided pieces are divided by the first support beam. inductively coupled plasma processing apparatus characterized by being. The inductively coupled plasma processing apparatus according to claim 3, wherein the second support beam is provided in a cross shape passing through a center of the dielectric window. The high-frequency antenna is configured by concentrically arranging a plurality of antenna portions provided so as to circulate along a circumferential direction of the dielectric window within a plane corresponding to the dielectric window. The inductively coupled plasma processing apparatus according to any one of claims 1 to 5 . The inductively coupled plasma processing apparatus according to any one of claims 1 to 6 , wherein a high frequency of 1 MHz to 27 MHz is applied to the high frequency antenna.

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