Inductively Coupled Plasma Processing Equipment

Abstract

A novel inductively coupled plasma processing apparatus is provided. [Solution] The inductively coupled plasma processing apparatus 1 includes a stage, a chamber, a gas supply channel, multiple antennas 54, and at least one high-frequency power supply 52. ​​Each of the multiple antennas 54 is a coil with less than one turn that includes a folded portion 62 that forms a recess that is recessed in a direction toward or away from the center 2c of the object 2 when the object 2 is viewed in a direction perpendicular to the mounting surface of the stage. When viewed in a direction perpendicular to the object 2 mounted on the stage, the multiple antennas 54 are aligned in the circumferential direction DC of the object 2, overlapping the object 2 and along the entire circumference of the object 2.

Description

[Technical Field]

[0001] The present invention relates to an inductively coupled plasma processing apparatus for processing an object using inductively coupled plasma. [Background technology]

[0002] A plasma CVD apparatus or a plasma etching apparatus is shown in Figure 4 of Patent Document 1. Patent Document 1 states that "multiple high-frequency antennas 10 are arranged on the side wall of a vacuum vessel 11 in parallel to a substrate S on a substrate holder 33." [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2013 / 030953 Summary of the Invention [Problem to be solved by the invention]

[0004] At least one embodiment of the present invention provides a novel inductively coupled plasma processing apparatus, which may be one or both of an inductively coupled plasma processing apparatus that can shorten the distance from the antenna to the target object and an inductively coupled plasma processing apparatus that can increase the degree of freedom in the characteristics of the plasma used to process the target object, or may be other than these. [Means for solving the problem]

[0005] One embodiment of the present invention provides an inductively coupled plasma processing apparatus including: a stage having a mounting surface on which a plate-shaped object can be mounted; a chamber forming an internal space in which the object mounted on the stage is placed; a gas supply line for supplying a process gas to the internal space of the chamber; a plurality of antennas for generating an inductive electric field that converts the process gas in the internal space of the chamber into plasma when a high-frequency current is supplied; and at least one high-frequency power supply for supplying the high-frequency current to the plurality of antennas, wherein each of the plurality of antennas is a coil with less than one turn that includes a folded portion that forms a recess that is recessed in a direction toward or away from the center of the object when the object is viewed in a direction perpendicular to the mounting surface; and the plurality of antennas are arranged in a circumferential direction of the object while overlapping the object and following the entire circumference of the object when the object is viewed in the perpendicular direction.

[0006] Another embodiment of the present invention provides an inductively coupled plasma processing apparatus comprising: a stage having a mounting surface on which a plate-shaped object can be mounted; a chamber forming an internal space in which the object mounted on the stage is placed; a gas supply line for supplying a process gas to the internal space of the chamber; a plurality of antennas that generate an inductive electric field that converts the process gas in the internal space of the chamber into plasma when a high-frequency current is supplied; a plurality of high-frequency power sources that individually supply the high-frequency current to the plurality of antennas; each of the plurality of antennas being a coil with less than one turn that includes a folded portion that forms a recess that is recessed in a direction toward or away from the center of the object when the object is viewed in a direction perpendicular to the mounting surface; and the plurality of antennas are arranged in a circumferential direction of the object along the entire circumference of the object when the object is viewed in the perpendicular direction.

[0007] In the two embodiments described above, at least one of the following features may be added to the inductively coupled plasma processing apparatus.

[0008] The multiple high-frequency power sources individually supply the high-frequency current to the multiple antennas so that the magnetic fields generated around two adjacent antennas in the circumferential direction of the object reinforce each other in the region between the two antennas.

[0009] The plurality of antennas are aligned in the circumferential direction of the object along the entire periphery of the object, overlapping the object when the object is viewed in the perpendicular direction.

[0010] When the object is viewed in the perpendicular direction, the plurality of antennas are aligned in the circumferential direction of the object along the entire circumference of the object, overlapping the outer periphery of the object.

[0011] The vertical distance from the object attached to the stage to the plurality of antennas is shorter than the length of the folded portion in the direction along the folded portion.

[0012] The object is disk-shaped, and the folded portion is trapezoidal in shape with a width that decreases toward the center of the object when the object is viewed in the vertical direction, and includes a tip portion corresponding to an upper base and a pair of side portions corresponding to a pair of oblique sides, and the circumferential distance between two adjacent antennas in the circumferential direction of the object is shorter than the length of the tip portions of the folded portion. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic diagram showing a vertical cross section of an inductively coupled plasma processing apparatus according to an embodiment of the present invention; [Figure 2] 2 is a schematic diagram showing a vertical cross section of an antenna housing chamber that houses an antenna. FIG. [Figure 3] FIG. 1 is a schematic diagram of an object attached to a stage viewed in a direction perpendicular to the object via multiple antennas. [Figure 4] FIG. [Figure 5] FIG. 1 is a schematic diagram showing an object and multiple antennas. [Figure 6] FIG. 6 is an enlarged view of an upper part of FIG. 5. [Figure 7] FIG. 7 is an enlarged view of a part of FIG. 6. [Figure 8] FIG. 10 is a conceptual diagram for explaining the direction of current flowing through two antennas adjacent to each other in the circumferential direction of the object. [Figure 9] FIG. 9 is a cross-sectional view taken along line IX-IX shown in FIG. 8. [Figure 10] 10 is a schematic diagram showing a vertical cross section of two antennas according to another embodiment of the present invention. [Figure 11] 11 is a graph showing changes in voltage of the two antennas shown in FIG. 10. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0015] Fig. 1 is a schematic diagram showing a vertical cross section of an inductively coupled plasma processing apparatus 1 according to one embodiment of the present invention. Fig. 2 is a schematic diagram showing a vertical cross section of an antenna housing chamber 59 that houses an antenna 54. Fig. 3 is a schematic diagram of an object 2 attached to a stage 14, viewed in a direction perpendicular to the object 2 via multiple antennas 54.

[0016] The inductively coupled plasma processing apparatus 1 is an apparatus that generates plasma by supplying a high-frequency current to an antenna 54. This plasma is called inductively coupled plasma. The object 2 is processed directly or indirectly by the inductively coupled plasma.

[0017] The processing performed on the object 2 by the inductively coupled plasma processing apparatus 1 using plasma may be any one of surface modification, deposition, and dry etching, or may be other than these. Deposition may be plasma CVD, which is classified as CVD (chemical vapor deposition), or may be any one of ion plating and sputtering, which are classified as PVD (physical vapor deposition), or may be other than these. Dry etching may be reactive ion etching, or may be other than these.

[0018] As shown in FIG. 1, the object 2 is a flat solid. The contour shape of the object 2 may be any of a circle, a rectangle, and a square, or may be other shapes. The object 2 may be a substrate for an integrated circuit including semiconductor elements such as transistors, or may be other shapes. If the object 2 is a substrate for an integrated circuit, the object 2 may be the substrate before or after the integrated circuit is manufactured, or may be the substrate during the integrated circuit is manufactured.

[0019] When the object 2 is a substrate for an integrated circuit, the substrate may be any one of a semiconductor wafer, a substrate for an FPD (Flat Panel Display) such as a liquid crystal display device or an organic EL (electroluminescence) display device, a substrate for an optical disk, a substrate for a magnetic disk, a substrate for a magneto-optical disk, a substrate for a photomask, a ceramic substrate, and a substrate for a solar cell, or may be other than these. The semiconductor wafer may be a silicon wafer or a wafer of a compound semiconductor.

[0020] When the objects 2 are semiconductor wafers on which integrated circuits including semiconductor elements are manufactured, and two objects 2 are to be bonded together, the treatment performed on the objects 2 by the inductively coupled plasma processing apparatus 1 using plasma may be activation of the surfaces of the objects 2 before bonding the two objects 2 together. Activation is one type of surface modification.

[0021] 1, the inductively coupled plasma processing apparatus 1 includes a stage 14 on which an object 2 is mounted, and a chamber 21 that houses the object 2 mounted on the stage 14. The inductively coupled plasma processing apparatus 1 further includes a gas exhaust path 32 that guides gas exhausted from an internal space 25 of the chamber 21, a gas supply path 42 that supplies a process gas to the internal space 25 of the chamber 21, and a plasma source 51 that generates plasma from the process gas in the chamber 21.

[0022] The stage 14 includes a horizontal mounting surface 14s on which the object 2 is mounted while being in contact with the object 2. The object 2 is mounted on the stage 14 in a horizontal position. The stage 14 may be an electrostatic chuck that holds the object 2 by electrical attraction, or may be something else. The inductively coupled plasma processing apparatus 1 may or may not include a high-frequency power supply 11 that applies a high-frequency voltage to the stage 14, which corresponds to an electrode. FIG. 1 shows an example of the former. In this example, the high-frequency power supply 11 is connected to the stage 14 via an impedance matching box 12 and a capacitor 13.

[0023] The object 2 is attached to the stage 14 so that the upper surface of the object 2 is in contact with the atmosphere in the chamber 21 and the lower surface of the object 2 is in contact with the stage 14. The upper surface of the object 2 is the processing surface 2s of the object 2 on which processing using plasma is performed. When performing sputtering, in which atoms scattered from a thin film material called a target are deposited on the processing surface 2s, the object 2 may be attached to the stage 14 with the processing surface 2s facing downward.

[0024] The chamber 21 includes a partition wall 23 that forms a passage opening 24 through which the object 2 passes and an internal space 25 in which the object 2 that has passed through the passage opening 24 is placed, and a door 22 that moves relative to the partition wall 23 to open and close the passage opening 24. When the door 22 closes the passage opening 24 of the partition wall 23, the internal space 25 of the partition wall 23, which corresponds to the internal space 25 of the chamber 21, is sealed. The object 2 is processed with the interior of the chamber 21 sealed.

[0025] Partition wall 23 may include a cylindrical peripheral wall 27 extending vertically, an upper wall 26 closing the upper end of peripheral wall 27, and a lower wall 28 closing the lower end of peripheral wall 27. Alternatively, partition wall 23 may be cup-shaped and open upward. In the latter case, door 22 may be a lid that moves up and down relative to partition wall 23 to open and close an opening in partition wall 23 corresponding to passage opening 24.

[0026] The gas exhaust path 32 is connected to an exhaust port 31 that opens in the internal space 25 of the chamber 21. The gas supply path 42 is connected to a supply port 41 that opens in the internal space 25 of the chamber 21. When the control device 3, which will be described later, opens the gas exhaust valve 33, the suction force of the exhaust pump 34 is transmitted to the internal space 25 of the chamber 21 via the gas exhaust path 32 and the exhaust port 31. When the control device 3 opens the gas supply valve 43, a process gas from a gas supply source is supplied to the internal space 25 of the chamber 21 via the gas supply path 42 and the supply port 41. The process gas may be a raw material gas that is converted into plasma that chemically reacts with the target object 2, or may be something else.

[0027] The plasma source 51 includes a plurality of antennas 54 that generate an induction electric field in the chamber 21 when a high-frequency current is supplied thereto, and at least one high-frequency power supply 52 that supplies a high-frequency current to the plurality of antennas 54 .

[0028] The antenna 54 is a metal conductor such as copper. The multiple antennas 54 are physically separated. All antennas 54 have the same specifications, such as shape, size, and material. The antenna 54 is also called a coil. The number of turns of the antenna 54 is less than one. The antenna 54 is a single cylindrical pipe or cylindrical shaft formed into a predetermined shape. The outer diameter of the antenna 54 in a cross section taken along a plane perpendicular to the center line of the antenna 54 is the same or approximately the same at every position on the antenna 54.

[0029] Antenna 54 may be an external antenna, an internal antenna, or a built-in antenna, or may be other than these. FIG. 2 shows an example in which antenna 54 is a built-in antenna. A built-in antenna is an antenna that does not protrude from the inner surface of chamber 21 that is in contact with the atmosphere within chamber 21, and at least a portion of it is disposed between the inner surface of chamber 21 and the outer surface of chamber 21. An external antenna is an antenna that is disposed outside chamber 21. An internal antenna is an antenna that protrudes from the inner surface of chamber 21. An internal antenna is also called a protruding antenna. When antenna 54 is an internal antenna, antenna 54 is covered by an antenna protector made of a dielectric material, such as a protective tube coaxial with antenna 54.

[0030] 2, the antenna 54 is inserted into two cylindrical antenna holders 55 called feedthroughs and is held in the chamber 21 via the two antenna holders 55. The antenna holders 55 may be in contact with the antenna 54, or may hold the antenna 54 via an antenna protector such as a protective tube. The antenna 54 includes an intermediate portion extending from one antenna holder 55 to the other antenna holder 55, a first arm portion passing through one antenna holder 55 and extending in a direction away from the intermediate portion, and a second arm portion passing through the other antenna holder 55 and extending in a direction away from the intermediate portion. The intermediate portion includes a folded portion 62 and a pair of support portions 61, which will be described later.

[0031] As shown in the example of FIG. 2 , when the antenna 54 is an embedded antenna, the antenna housing chamber 59 includes a hole 57 in the partition wall 23 that opens on the outer and inner surfaces of the partition wall 23, a flange 56 that closes the opening on the outer surface of the partition wall 23, and an antenna cover 58 that closes the opening on the inner surface of the partition wall 23. The flange 56 and the antenna cover 58 are attached to the partition wall 23. The antenna 54 is held by the flange 56 via two antenna holders 55. The antenna 54 is not in contact with the partition wall 23 or the antenna cover 58. The flange 56, the antenna cover 58, and the antenna holder 55 are all made of a dielectric material such as alumina or quartz. The inner surface of the partition wall 23 and the inner surface of the antenna cover 58 are included in the inner surface of the chamber 21 that is in contact with the atmosphere within the chamber 21.

[0032] The antenna housing chamber 59 is formed by the surfaces of the flange 56 and the antenna cover 58 and the inner surface of a hole 57 in the partition wall 23 extending from the flange 56 to the antenna cover 58. The space between the inner surface of the antenna housing chamber 59 and the surface of the antenna 54 may be filled with a solid dielectric material. In FIG. 2, the solid dielectric material filling the antenna housing chamber 59 is not shown. This is also the case in FIG. 10, which will be described later. The solid dielectric material may be powder of the dielectric material bonded or unbonded to each other, or may be one or more clumps of the dielectric material larger than the particles of the powder of the dielectric material.

[0033] As shown in Fig. 3, the multiple antennas 54 are connected to at least one high-frequency power supply 52. ​​Fig. 3 shows an example in which one high-frequency power supply 52 is provided for each antenna 54. In this example, the multiple antennas 54 are connected to the multiple high-frequency power supplies 52 in a one-to-one relationship. The control device 3 controls all the high-frequency power supplies 52 to control the current, voltage, phase, and the like supplied to each antenna 54.

[0034] The at least one high frequency power supply 52 does not have to be a plurality of high frequency power supplies 52 in the same number as the antennas 54. Specifically, the at least one high frequency power supply 52 may be a plurality of high frequency power supplies 52 each connected to a plurality of different antennas 54, or may be a single high frequency power supply 52 to which all of the antennas 54 are connected. In these cases, two or more antennas 54 are connected in parallel to a single high frequency power supply 52.

[0035] Antenna 54 includes an input terminal connected to high-frequency power supply 52 and a grounded earth terminal. High-frequency power supply 52 includes an output terminal connected to antenna 54 and a grounded earth terminal. The output terminal of high-frequency power supply 52 is connected to the input terminal of antenna 54 via impedance matching device 53 (see FIG. 2). Impedance matching device 53 is a device that brings the input impedance of a circuit to which high-frequency current from high-frequency power supply 52 is supplied closer to the output impedance of high-frequency power supply 52. ​​Antenna 54 and impedance matching device 53 are included in the circuit to which high-frequency current from high-frequency power supply 52 is supplied.

[0036] The inductively coupled plasma processing apparatus 1 includes a control device 3 that controls the electronic and electrical devices provided in the inductively coupled plasma processing apparatus 1. The control device 3 includes at least one computer that can communicate with each other. The computer includes a memory 3b that stores information such as programs, and a CPU 3a (central processing unit) that controls the inductively coupled plasma processing apparatus 1 in accordance with the programs stored in the memory 3b. The control device 3 controls the inductively coupled plasma processing apparatus 1 to cause the inductively coupled plasma processing apparatus 1 to perform its functions. In other words, the control device 3 is programmed to cause the inductively coupled plasma processing apparatus 1 to perform its functions.

[0037] Next, the antenna 54 will be described.

[0038] Hereinafter, viewing the object 2 attached to the stage 14 in a direction perpendicular to the attachment surface 14s of the stage 14 via the multiple antennas 54 may be simply referred to as viewing in the vertical direction.

[0039] Fig. 4 is a perspective view of the antenna 54. Fig. 5 is a schematic diagram showing the object 2 and the multiple antennas 54. The upper part of Fig. 5 shows a schematic diagram of the object 2 and the multiple antennas 54 viewed vertically. The lower part of Fig. 5 shows a schematic diagram of the object 2 and the multiple antennas 54 viewed horizontally. Fig. 6 is an enlarged view of a portion of the upper part of Fig. 5. Fig. 7 is an enlarged view of a portion of Fig. 6.

[0040] As shown in the upper part of Figure 5, the antenna 54 includes a folded portion 62 having a recess 65 formed therein, which is recessed in a direction toward or away from the center 2c of the object 2 when viewed vertically. The upper part of Figure 5 shows an example in which the recess 65 is formed to be recessed toward the center 2c of the object 2 when viewed vertically. In this example, the antenna 54 further includes a pair of support portions 61 extending upward from both ends of the folded portion 62 (see also Figure 4). The pair of support portions 61 extend downward from the two antenna holders 55 (see Figure 2) described above. The folded portion 62 is supported by the pair of support portions 61.

[0041] The folded portion 62 has a line-symmetric shape when viewed in the vertical direction. The folded portion 62 may also have a shape that is not line-symmetric. The folded portion 62 may be any of, or other than, a U-shape, a V-shape, a W-shape, a C-shape, a circular arc (an arc with a central angle less than 360 degrees), a rectangle with one long or short side omitted, and a square with one side omitted. FIG. 5 shows an example in which the folded portion 62 is an isosceles trapezoid with the lower base omitted. When the folded portion 62 is a U-shape, a C-shape, or a circular arc, the radius of curvature of the folded portion 62 is smaller than the shortest distance from the center 2c of the object 2 to the outer periphery 2o of the object 2.

[0042] As shown in Fig. 6, when the folded portion 62 is a polygon such as a trapezoid, the folded portion 62 has one or more corners. The corners of the folded portion 62 may be formed by two straight lines that intersect with each other, or may be formed by a curve such as an arc. Fig. 6 shows an example in which the folded portion 62 has two arc-shaped corners. The corners of the folded portion 62 correspond to the joints of the tip portion 63 and the side portions 64, which will be described later.

[0043] The folded portion 62 includes a tip portion 63 that forms the bottom of the recess 65, and a pair of side portions 64 that extend from both ends of the tip portion 63 toward the entrance of the recess 65. The pair of support portions 61 extend upward from the pair of side portions 64. The ends of the pair of side portions 64 opposite the tip portion 63 form the entrance of the recess 65. The pair of side portions 64 may be parallel or non-parallel. In the latter case, the pair of side portions 64 may be inclined in opposite directions relative to the axis of symmetry 66. Figure 6 shows an example in which the pair of side portions 64 are inclined at equal angles in opposite directions relative to the axis of symmetry 66.

[0044] FIG. 6 shows an example in which the tip portion 63 is linear and perpendicular to the axis of symmetry 66, and the side portion 64 is linear and inclined relative to the tip portion 63. In this example, the tip portion 63 corresponds to the upper base of a trapezoid, and the side portion 64 corresponds to the hypotenuse of the trapezoid. The tip portion 63 may be an arc or a point, or may have a shape other than these. When the folded portion 62 is axially symmetrical U-shaped, the tip portion 63 is an arc that intersects with the axis of symmetry 66. When the folded portion 62 is V-shaped, the tip portion 63 is a point located on the axis of symmetry 66.

[0045] 7, the direction of symmetry axis 66 when viewed vertically is defined as the height direction of folded portion 62, and the direction perpendicular to symmetry axis 66 when viewed vertically is defined as the width direction of folded portion 62. The maximum length of folded portion 62 in the height direction is defined as height H1 of folded portion 62, and the length of folded portion 62 in the width direction is defined as width W1 of folded portion 62.

[0046] The width W1 of the folded portion 62 may be constant or may vary. The folded portion 62 may include portions where the width W1 varies and portions where the width W1 is constant. If the width W1 is constant, the width W1 may be equal to the height H1, or may be greater than or less than the height H1. If the width W1 varies, the minimum or maximum value of the width W1 may be equal to the height H1, or may be greater than or less than the height H1. The height H1 may be greater than the minimum value of the width W1 and less than the maximum value of the width W1. The minimum value of the width W1 may be equal to the shortest distance from the center 2c of the object 2 to the folded portion 62 when viewed vertically, or may be greater than or less than this shortest distance.

[0047] When the folded portion 62 is trapezoidal as in the example shown in Figure 7, the length of the upper base of the folded portion 62 corresponds to the length L2 of the tip portion 63. The length of the upper base of the folded portion 62 may be equal to the height H1 of the folded portion 62, or may be greater than or less than the height H1. The same applies to the hypotenuse of the folded portion 62. The length of the upper base of the folded portion 62 may be equal to the length of the hypotenuse of the folded portion 62, or may be greater than or less than this length.

[0048] When viewed vertically, the contour of the folded portion 62 includes an inner contour line 67i that forms the recess 65 and an outer contour line 67o that extends along and outside the inner contour line 67i. In FIG. 7, the inner contour line 67i and the outer contour line 67o are indicated by thick lines. A boundary point 67b in FIG. 7 indicates the boundary between the inner contour line 67i and the outer contour line 67o. The boundary point 67b corresponds to the end of the folded portion 62 in the height direction of the folded portion 62 (the vertical direction on the paper in FIG. 7).

[0049] The height H1 corresponds to the maximum length of the outer contour line 67o in the height direction of the folded portion 62. The width W1 corresponds to the length of the outer contour line 67o in the width direction of the folded portion 62. The inner height of the folded portion 62 corresponds to the maximum length of the inner contour line 67i in the height direction of the folded portion 62. The inner width (spacing) of the folded portion 62 corresponds to the length of the inner contour line 67i in the width direction of the folded portion 62. The relationship between the inner height of the folded portion 62 and the inner width of the folded portion 62 may be the same as the relationship between the height H1 and the width W1 described above.

[0050] As shown in the lower part of FIG. 5, all portions of the folded portion 62 are arranged on a single plane. In other words, the folded portion 62 extends along a single plane. The folded portion 62 may be arranged on a horizontal plane, or on a plane inclined relative to the horizontal plane. In the latter case, the folded portion 62 may be arranged on a plane that rises or falls as it approaches the center 2c of the target object 2. The lower part of FIG. 5 shows an example in which the folded portion 62 is horizontal and arranged on a single horizontal plane. In this example, all of the folded portions 62 are arranged on a single horizontal plane.

[0051] Distance L1 shown in the lower part of Fig. 5 means the vertical distance from the target object 2 attached to the stage 14 to the multiple antennas 54. Distance L1 may be equal to the length of the folded portion 62 in the direction along the folded portion 62 (the length of the outer contour line 67o shown in Fig. 7), or may be greater than or less than this length. The lower part of Fig. 5 shows an example in which distance L1 is shorter than the length of the folded portion 62 in the direction along the folded portion 62.

[0052] As shown in the upper part of Fig. 5, the multiple folded portions 62 are arranged in the circumferential direction DC of the object 2 (the direction along the outer periphery 2o of the object 2) along the entire circumference of the object 2 when viewed vertically. The interval between two adjacent folded portions 62 in the circumferential direction DC of the object 2 (the interval in the circumferential direction DC of the object 2) may be uniform or uneven. The upper part of Fig. 5 shows an example in which the multiple folded portions 62 are arranged at equal intervals in the circumferential direction DC of the object 2.

[0053] When viewed in the vertical direction, the folded portion 62 may or may not overlap the object 2. In the former case, the folded portion 62 may or may not overlap the outer periphery 2o of the object 2. The upper side of FIG. 5 shows an example in which all of the folded portions 62 overlap the outer periphery 2o of the object 2. In this example, some of the folded portions 62 are disposed inside the outer periphery 2o of the object 2, and the remaining portions of the folded portions 62 are disposed outside the outer periphery 2o of the object 2.

[0054] As described above, the shape of the folded portion 62 is axisymmetric with respect to the axis of symmetry 66 (see FIG. 6) when viewed in the vertical direction. The antenna 54 is disposed so that the axis of symmetry 66 is perpendicular to the tangent line TL to the outer periphery 2o of the object 2 (the tangent line TL at the intersection of the axis of symmetry 66 and the outer periphery 2o) or perpendicular to the outer periphery 2o when viewed in the vertical direction. FIG. 6 shows an example in which the object 2 is a circular plate and the axis of symmetry 66 is perpendicular to the tangent line TL. When the object 2 is a rectangular or square plate, the axis of symmetry 66 is perpendicular to the outer periphery 2o of the object 2.

[0055] The shortest distance from the center 2c of the object 2 (see FIG. 5) to the folded portion 62 when viewed vertically corresponds to the shortest distance from the center 2c of the object 2 to the antenna 54 when viewed vertically. This shortest distance is the same for all antennas 54. This shortest distance may be equal to the height H1 of the folded portion 62 (see FIG. 7), or may be greater than or less than the height H1. When the folded portion 62 overlaps the outer periphery 2o of the object 2 when viewed vertically, the distance in the height direction of the folded portion 62 from the intersection of the axis of symmetry 66 and the outer contour 67o of the folded portion 62 (see FIG. 7) to the intersection of the axis of symmetry 66 and the outer periphery 2o of the object 2 may be greater than or less than half the height H1 of the folded portion 62.

[0056] Hereinafter, two adjacent folded portions 62 in the circumferential direction DC of the object 2 may be referred to as two adjacent folded portions 62, and the two inner side portions 64 of the four side portions 64 of two adjacent folded portions 62 may be referred to as two adjacent side portions 64. The two adjacent side portions 64 are not a pair of side portions 64 of one folded portion 62, but a pair of side portions 64 of separate folded portions 62.

[0057] Two adjacent side portions 64 indirectly face each other in the horizontal direction. In Figure 6, the two adjacent side portions 64 are depicted as if they are directly facing each other in the horizontal direction, but in reality, a part of the chamber 21 is disposed between them. When viewed vertically, the two adjacent side portions 64 may be parallel or non-parallel. Figure 6 shows an example of the former.

[0058] The minimum value of the spacing between two adjacent side portions 64 corresponds to the shortest distance between the two adjacent side portions 64. The minimum value of the spacing between two adjacent side portions 64 may be equal to the height H1 (see FIG. 7) of the folded portion 62, or may be greater than or smaller than the height H1. The minimum value of the spacing between two adjacent side portions 64 may be equal to the outer diameter of the antenna 54 in a cross section of the antenna 54 taken along a plane perpendicular to the center line of the antenna 54, or may be greater than or smaller than the outer diameter.

[0059] The distance between two adjacent antennas 54 in the circumferential direction DC means the minimum distance between two adjacent side portions 64. The distance between two adjacent antennas 54 in the circumferential direction DC may be equal to the length L2 (see FIG. 7) of the tip end 63 of the folded portion 62, or may be greater than or less than the length L2. FIG. 6 shows an example in which the distance between two adjacent antennas 54 in the circumferential direction DC is shorter than the length L2 of the tip end 63 of the folded portion 62.

[0060] Next, the magnetic field generated around the antenna 54 will be described.

[0061] 8 is a conceptual diagram for explaining the direction of current flowing through two antennas 54 adjacent to each other in the circumferential direction DC of the target 2. FIG. 9 is a cross-sectional view taken along line IX-IX shown in FIG.

[0062] When processing the object 2, the object 2 is placed on the stage 14 in the chamber 21, and the chamber 21 is sealed. The atmosphere in the chamber 21 is then exhausted, and a process gas is supplied into the chamber 21. Then, a high-frequency current is supplied to all of the antennas 54. This ionizes the process gas in the chamber 21, generating plasma in the chamber 21. The processing surface 2s of the object 2 is processed directly or indirectly by the ions and radicals contained in this plasma.

[0063] When a high-frequency current flows through the folded portion 62 of the antenna 54, a magnetic field is generated around the tip 63 and the pair of side portions 64 of the folded portion 62. This change in the magnetic field generates an induced electric field in the chamber 21. This induced electric field ionizes the process gas in the chamber 21.

[0064] The magnetic field generated around the tip 63 of the folded portion 62 and the magnetic field generated around the side portions 64 of the folded portion 62 reinforce each other. The magnetic fields generated around the pair of side portions 64 of the folded portion 62 also reinforce each other. In particular, because the distance between the tip 63 and the side portions 64 is short at the joint between the tip 63 and the side portions 64, a stronger magnetic field is generated compared to positions away from the joint. Therefore, a stronger magnetic field is generated in the region inside the folded portion 62 and in the regions above and below it. This generates a stronger induced electric field within the chamber 21.

[0065] Two adjacent side portions 64 (the two inner side portions 64 of the four side portions 64 of two folded portions 62 adjacent to each other in the circumferential direction DC of the object 2) are defined as a first side portion 64A and a second side portion 64B. In Fig. 8, the direction of the current flowing through the first side portion 64A and the second side portion 64B is indicated by thick arrows.

[0066] When a current is flowing through the first side portion 64A in a direction away from the tip portion 63, the current may also flow through the second side portion 64B in a direction toward the tip portion 63, or may also flow through the second side portion 64B in a direction away from the tip portion 63. Figures 8 and 9 show an example of the former. In the former case, when a current is flowing through the first side portion 64A in a direction away from the tip portion 63, there may or may not be a period during which the current is flowing through the second side portion 64B in a direction away from the tip portion 63.

[0067] First magnetic field lines 64a in Fig. 9 indicate magnetic field lines generated around first side portion 64A. Second magnetic field lines 64b in Fig. 9 indicate magnetic field lines generated around second side portion 64B. The hatched areas in Fig. 9 indicate areas where magnetic fields reinforce each other.

[0068] When a current flows through the first side portion 64A in a direction away from the tip portion 63 and then flows through the second side portion 64B in a direction toward the tip portion 63, the magnetic fields generated around the first side portion 64A and the second side portion 64B reinforce each other, as shown in FIG. 9 . The same applies when the direction of the current flowing through the first side portion 64A and the second side portion 64B changes. Therefore, if the control device 3 controls the phase of the high-frequency current supplied to all antennas 54 so that there is a period in which the current flows in opposite directions through the first side portion 64A and the second side portion 64B, a stronger magnetic field is generated in the region between the first side portion 64A and the second side portion 64B and in the regions above and below it. This allows for efficient plasma generation.

[0069] Next, the effects of this embodiment will be described.

[0070] In this embodiment, the target object 2 is carried into the chamber 21 and attached to the stage 14. Then, a process gas is supplied into the chamber 21. Then, a high-frequency current is supplied from at least one high-frequency power supply 52 to multiple antennas 54. When the high-frequency current is supplied to the multiple antennas 54, an induced electric field is generated in the chamber 21. This ionizes the process gas in the chamber 21, and plasma is generated in the chamber 21. The target object 2 attached to the stage 14 is processed by contact between this plasma and the target object 2, etc.

[0071] Each of the multiple antennas 54 is a coil with less than one turn. The inductance of the coil is proportional to the square of the number of turns of the coil and proportional to the cross-sectional area of ​​the coil (the area inside the coil). The number of turns of the coil is less than one. Furthermore, since multiple antennas 54 are provided, the cross-sectional area of ​​the coil is reduced compared to when high-frequency current is supplied to only one coil (antenna 54). This reduces the inductance of the antenna 54 and the plasma potential. The reduction in plasma potential can eliminate or reduce damage to the target 2.

[0072] Additionally, each of the multiple antennas 54 includes a folded portion 62 having a recess 65 formed therein that is recessed in a direction toward or away from the center 2c of the object 2 when viewed in a direction perpendicular to the object 2 attached to the stage 14. Therefore, compared to when the antenna 54 is a vertical U-shape that opens upward, the portion of the antenna 54 that contributes to plasma generation can be made longer, thereby improving the plasma generation efficiency.

[0073] Furthermore, the multiple antennas 54 are aligned in the circumferential direction DC of the object 2 along the entire circumference of the object 2, overlapping the object 2 when viewed in a direction perpendicular to the object 2 attached to the stage 14. Because the multiple antennas 54 are aligned in the circumferential direction DC of the object 2 along the entire circumference of the object 2, the uniformity of the processing of the object 2 by plasma can be improved. Furthermore, the distance from the antennas 54 to the object 2 can be shortened compared to when the multiple antennas 54 do not overlap the object 2. This allows the distance between the space with high plasma electron density and the object 2 to be shortened.

[0074] In this embodiment, high-frequency current is supplied individually to the multiple antennas 54. In other words, one high-frequency power supply 52 is provided for each antenna 54. Therefore, the current, voltage, frequency, phase, etc. can be set for each antenna 54. Plasma characteristics such as electron density change depending on the characteristics of the power supplied to the antenna 54. Plasmas generated near the individual antennas 54 affect each other. Therefore, by supplying high-frequency current individually to the multiple antennas 54, the degree of freedom in the characteristics of the plasma used to process the target object 2 can be increased.

[0075] In this embodiment, when a current flows through the antenna 54, a magnetic field is generated that rotates clockwise relative to the direction of the current flow (right-hand rule). The folded portion 62 of the antenna 54 forms a recess 65 that is recessed in a direction toward or away from the center 2c of the object 2 when viewed in a direction perpendicular to the object 2 attached to the stage 14. When a current flows through the folded portion 62 having such a shape, the magnetic fields generated by the application of current to the folded portion 62 reinforce each other in the region inside the folded portion 62 and in the regions above and below it.

[0076] Furthermore, the multiple high-frequency power supplies 52 individually supply high-frequency currents to the multiple antennas 54 so that the magnetic fields generated around two antennas 54 adjacent to each other in the circumferential direction DC of the target 2 reinforce each other in the region between the two antennas 54. If the magnetic fields reinforce each other in the region between the two antennas 54, the magnetic fields also reinforce each other in the regions above and below that region. Therefore, a stronger induced electric field can be generated in the region between the two antennas 54 adjacent to each other in the circumferential direction DC of the target 2 and in the regions above and below it. This can improve the uniformity of the plasma.

[0077] In this embodiment, when viewed in a direction perpendicular to the object 2 attached to the stage 14, the multiple antennas 54 are not only aligned along the entire circumference of the object 2 in the circumferential direction DC of the object 2, but also overlap the outer periphery 2o of the object 2. When viewed in a direction perpendicular to the object 2 attached to the stage 14, a portion of the antenna 54 is disposed inside the outer periphery 2o of the object 2, and the remaining portion of the antenna 54 is disposed outside the outer periphery 2o of the object 2. Therefore, plasma with high electron density is generated in multiple spaces that overlap the outer periphery 2o of the object 2 when viewed in a direction perpendicular to the object 2 attached to the stage 14. The plasma moves from these spaces toward the outer periphery 2o of the object 2 and the center 2c of the object 2. This improves the uniformity of the plasma treatment of the object 2.

[0078] In this embodiment, the vertical distance L1 (see FIG. 5) from the target object 2 attached to the stage 14 to the multiple antennas 54 is shorter than the length of the turn-back portion 62 in the direction along the turn-back portion 62 (the length of the outer contour line 67o shown in FIG. 7). Near the multiple antennas 54, plasma is generated with a distribution corresponding to the arrangement of the multiple antennas 54. Since the multiple antennas 54 are not only aligned along the entire circumference of the target object 2 in the circumferential direction DC of the target object 2 but also overlap with the target object 2, unevenness in the plasma distribution near the multiple antennas 54 can be reduced. Therefore, the target object 2 can be uniformly processed without increasing the distance L1. Furthermore, since the length of the turn-back portion 62 in the direction along the turn-back portion 62 is relatively long, the portion of the antenna 54 that contributes to plasma generation can be increased.

[0079] In this embodiment, multiple antennas 54 are lined up in the circumferential direction DC of the disk-shaped object 2 along the entire circumference of the object 2 and overlap the disk-shaped object 2. When viewed in a direction perpendicular to the object 2 attached to the stage 14, the folded portion 62 of the antenna 54 is trapezoidal in shape with a width that decreases in the direction toward the center 2c of the object 2. Therefore, the spacing between the multiple antennas 54 on the outer periphery 2o of the object 2 can be narrower than when the folded portion 62 is a rectangle or square with one side omitted.

[0080] The trapezoidal folded portion 62 includes a tip portion 63 corresponding to the upper base and a pair of side portions 64 corresponding to a pair of oblique sides. The distance in the circumferential direction DC between two adjacent antennas 54 in the circumferential direction DC of the target 2 is shorter than the length L2 (see FIG. 7 ) of the tip portions 63 of the folded portion 62. Therefore, the distance between the multiple antennas 54 is relatively narrow. By narrowing the distance between the multiple antennas 54, it is possible to reduce the unevenness of the plasma distribution near the multiple antennas 54.

[0081] Next, another embodiment will be described.

[0082] As mentioned above, the antenna 54 is not limited to an embedded antenna, but may be an external antenna or an internal antenna. Figure 10 shows an example in which the antenna 54 is an internal antenna, also known as a protruding antenna.

[0083] 10 , the antenna 54 is inserted into a hole 57 in the partition wall 23, which opens on the outer and inner surfaces of the partition wall 23, and protrudes from the inner surface of the partition wall 23 toward the internal space 25 of the chamber 21 where plasma is generated. The shape of the antenna 54 and the arrangement of the multiple antennas 54 are the same as those described above. The antenna 54 is housed in a protective case 71 attached to the partition wall 23 so as to cover the opening on the internal surface of the partition wall 23. The protective case 71 is an example of an antenna protector that protects the antenna 54 from the plasma generated in the internal space 25 of the chamber 21.

[0084] Fig. 10 shows two antennas 54 adjacent to each other in the circumferential direction DC. Fig. 11 is a graph showing changes in voltage of the two antennas 54 shown in Fig. 10. The dashed-dotted line in Fig. 11 shows changes in voltage of one of the antennas 54. The dashed-two-dotted line in Fig. 11 shows changes in voltage of the other antenna 54.

[0085] The control device 3 may control the multiple high-frequency power supplies 52 so that voltages are applied to two adjacent antennas 54 with a phase difference greater than 0 degrees but less than 360 degrees. FIG. 11 shows an example in which the phase difference between the voltages of two adjacent antennas 54 is 180 degrees. In this way, the voltage difference between the two adjacent antennas 54 can be increased. Electrons in the chamber 21 are accelerated between the two adjacent antennas 54 due to this voltage difference. Therefore, plasma can be generated more efficiently.

[0086] The inner surface of chamber 21 includes a cylindrical side surface extending vertically, an upper surface (ceiling surface) closing the upper end of the side surface, and a lower surface closing the lower end of the side surface. When antenna 54 protrudes from the inner surface of chamber 21, antenna 54 may protrude from a portion other than the upper surface, such as the side surface. When antenna 54 protrudes from the side surface of the inner surface of chamber 21, the pair of supports 61 may be omitted from antenna 54.

[0087] Any two or more of the above-mentioned features may be combined. Any two or more of the above-mentioned steps may be combined.

[0088] Although the embodiments of the present invention have been described in detail, these are merely examples used to clarify the technical contents of the present invention, and the present invention should not be construed as being limited to these examples. The spirit and scope of the present invention are limited only by the appended claims. [Explanation of symbols]

[0089] 1: inductively coupled plasma processing apparatus, 2: object, 2c: center, 2o: outer periphery, 2s: processing surface, 3: control device, 3a: CPU, 3b: memory, 11: high frequency power supply, 12: impedance matching box, 13: capacitor, 14: stage, 14s: mounting surface, 21: chamber, 22: door, 23: partition wall, 24: passage port, 25: internal space, 26: upper wall, 27: peripheral wall, 28: lower wall, 31: exhaust port, 32: gas exhaust path, 33: gas exhaust valve, 34: exhaust pump, 41: supply port, 42: gas supply path, 43: gas supply valve, 51 : plasma source, 52: high frequency power supply, 53: impedance matching box, 54: antenna, 55: antenna holder, 56: flange, 57: hole, 58: antenna cover, 59: antenna housing, 61: support portion, 62: folded portion, 63: tip portion, 64: side portion, 64A: first side portion, 64B: second side portion, 64a: first magnetic field line, 64b: second magnetic field line, 65: recess, 66: axis of symmetry, 67b: boundary point, 67i: inner contour line, 67o: outer contour line, 71: protective case, DC: circumferential direction, H1: height, L1: distance, TL: tangent line

Claims

1. a stage having a mounting surface on which a plate-shaped object is mounted; a chamber forming an internal space in which the object attached to the stage is placed; a gas supply path for supplying a process gas to the internal space of the chamber; a plurality of antennas that, when supplied with high frequency current, generate an induction electric field that transforms the process gas in the interior space of the chamber into plasma; at least one high frequency power source that supplies the high frequency current to the plurality of antennas; Each of the plurality of antennas is a coil with less than one turn, including a folded portion that forms a recess that is recessed in a direction toward the center of the object or in a direction away from the center of the object when the object is viewed in a direction perpendicular to the mounting surface, The inductively coupled plasma processing apparatus, wherein the plurality of antennas are aligned in a circumferential direction of the object along the entire circumference of the object while overlapping the object when the object is viewed in the perpendicular direction.

2. a stage having a mounting surface on which a plate-shaped object is mounted; a chamber forming an internal space in which the object attached to the stage is placed; a gas supply path for supplying a process gas to the internal space of the chamber; a plurality of antennas that, when supplied with high frequency current, generate an induction electric field that transforms the process gas in the interior space of the chamber into plasma; a plurality of high frequency power sources that individually supply the high frequency current to the plurality of antennas; Each of the plurality of antennas is a coil with less than one turn, including a folded portion that forms a recess that is recessed in a direction toward the center of the object or in a direction away from the center of the object when the object is viewed in a direction perpendicular to the mounting surface, The inductively coupled plasma processing apparatus, wherein the plurality of antennas are arranged in a circumferential direction of the object along the entire circumference of the object when the object is viewed in the perpendicular direction.

3. 3. The inductively coupled plasma processing apparatus according to claim 2, wherein the plurality of high-frequency power sources individually supply the high-frequency currents to the plurality of antennas so that magnetic fields generated around two of the antennas adjacent to each other in the circumferential direction of the object reinforce each other in a region between the two antennas.

4. 4. The inductively coupled plasma processing apparatus according to claim 2, wherein the plurality of antennas are aligned in a circumferential direction of the object along the entire circumference of the object while overlapping the object when the object is viewed in the perpendicular direction.

5. 5. The inductively coupled plasma processing apparatus of claim 4, wherein the plurality of antennas are aligned in the circumferential direction of the object along the entire circumference of the object while overlapping the outer periphery of the object when the object is viewed in the perpendicular direction.

6. 5. The inductively coupled plasma processing apparatus according to claim 4, wherein a vertical distance from the object attached to the stage to the plurality of antennas is shorter than a length of the folded portion in a direction along the folded portion.

7. the object is disk-shaped, the folded portion has a trapezoidal shape whose width decreases toward the center of the object when the object is viewed in the perpendicular direction, and includes a tip portion corresponding to an upper base and a pair of side portions corresponding to a pair of oblique sides; 4. The inductively coupled plasma processing apparatus according to claim 1, wherein a distance in the circumferential direction between two of the antennas adjacent in the circumferential direction of the object is shorter than a length of the tip end of the folded portion.

Images