JP2004509429A - Plasma reactor with symmetrical parallel conductor coil antenna - Google Patents

Abstract

The present invention is implemented in a plasma reactor for processing semiconductor workpieces. The reactor is on a vacuum chamber with side walls and a ceiling, a workpiece support pedestal generally facing the ceiling in the chamber, a gas input capable of introducing process gas into the chamber, and a top of the ceiling, at least approximately one from axisymmetric. A first multi-conductor solenoid-like interleaved parallel conductor coil antenna wound about axisymmetric substantially perpendicular to the top of each coaxial helical solenoid displaced laterally. Each helical solenoid is offset from the other helical conductor. In another embodiment, the antenna is on the top and the segmentation on the solenoid having a first plurality of conductors wound about a symmetry axis substantially perpendicular to the top in each coaxial side-by-side helical solenoid. The parallel conductor coil antenna. Each helical solenoid is offset from the other helical solenoid closest to the direction perpendicular to the axis of symmetry by a distance equal to the width of the conductors, so that each helical solenoid has a slightly different diameter. Have.

Description

[0001]
(Background of the Invention)
Plasma reactors used to fabricate semiconductor microelectronic circuits can use RF inductively coupled magnetic fields to maintain a plasma formed from the process gas. Such a plasma is useful for performing etching and deposition processes. In general, a high frequency RF source power signal is applied to a coil antenna near the ceiling of the reactor chamber. The semiconductor wafer or workpiece support on the pedestal in the chamber has a bias RF signal applied thereto. The power of the signal supplied to the coil antenna mainly determines the plasma ion density in the chamber, while the power of the bias signal applied to the wafer determines the ion energy on the wafer surface. One problem with such coil antennas is that there is a relatively large voltage drop across the antenna that induces undesirable effects in plasmas such as arcs. This effect becomes more severe as the frequency of the source power signal applied to the coil antenna increases because the reactance of the coil antenna is proportional to the frequency. In some reactors, this problem is solved by limiting the frequency to a low range, for example about 2 MHz. Unfortunately, at such low frequencies, the coupling of RF power to the plasma is not very efficient. It is often easy to achieve a stable high density plasma discharge at a frequency in the range of 10 MHz to 20 MHz. Another drawback of operating at low frequencies (eg 2 MHz) is that the elements of these elements as impedance matching networks are very large and therefore bothersome and expensive.
[0002]
Another problem with coil antennas is that efficient inductive coupling to the antenna is generally achieved by increasing the number of turns of the coil forming a high magnetic flux density. This increases the inductive reactance of the coil and increases the circuit Q (ratio of circuit reactance to resistance) because the resistance of the circuit (consisting mainly of plasma resistance) remains constant. This in turn leads to this instability and difficulty of maintaining impedance matching across changing chamber conditions. The inductance of the coil is so great that instability occurs especially when self-resonance occurs near the frequency of the RF signal applied to the coil, coupled with stray capacitance.
[0003]
These problems are: “Inductively Coupled Plasma Reactor With Symmetrical Parallel Multiples coiling A Common RF Terminal: Inductively coupled plasma X u with a symmetrical parallel multi-coil having a common RF terminal” Inductive with symmetrically spirally arranged conductors interleaved on the outside, as described elsewhere in US Pat. No. 5,919,389 issued on Jul. 6, 1999. This is solved by the invention of the coil antenna. By dividing the antenna into multiple conductors in an interleaved symmetrical pattern, the voltage drop is reduced. This is because it is divided into multiple conductors of the antenna. Therefore, the frequency of the source power signal is not limited as in a conventional coil antenna. This type of coil antenna is referred to herein as an “interleaved” coil antenna. Such interleaved coil antennas not only have a flat pancake shape, but also a dome shape, a dome shape with a cylindrical skirt around the sidewall, or a flat with a cylindrical skirt around the sidewall of the chamber Various configurations having a pancake shape are disclosed (US Pat. No. 5,919,389).
[0004]
One limitation of coil antennas placed on the ceiling of the chamber (not only the traditional format but also the interleaved format) is that the mutual inductance between adjacent conductors of the antenna is generally horizontal (typically RF power). Is perpendicular to the vertical direction, which must be inductively coupled to the plasma. This is one important factor that limits the spatial control of power deposition on the plasma. The object of the present invention is to overcome this limitation in the spatial control of inductive coupling.
[0005]
In general, in the case of inner and outer coil antennas, they are physically arranged radially (rather than being limited to their respective radii), i.e. horizontally, so that their radial position is accordingly Diffused. This is a particularly true horizontal “pancake” shape. Thus, changing the relative distribution of RF power supplied between the inner and outer antennas limits the ability to change the radial distribution of the plasma ion distribution. This problem is particularly serious when processing semiconductor wafers having a large diameter (eg, 300 mm). This is because as the wafer size increases, it becomes more difficult to maintain a uniform plasma ion density across the entire wafer surface. The radial distribution of the plasma ion density can be easily adjusted by adjusting the radial distribution of the magnetic field applied from the overhead antenna. It is this magnetic field that determines the plasma ion density. Therefore, there is a need for the ability to trim or adjust the radial distribution of the applied RF magnetic field as the wafer size increases. It is therefore necessary to increase the influence of the distribution of RF power applied between the inner and outer antennas, in particular to limit each of the inner and outer antennas to separate or very narrow radial positions. It is necessary to achieve this.
[0006]
Another problem encountered when using inner and outer coil antennas is that they generally have significantly different impedances because the outer antenna has a significantly larger inductance than the inner antenna (because of the longer outer radius distance). It is. As a result, the impedance of the two coils is not the same. This problem becomes more serious as the chamber size increases to accommodate larger semiconductor wafers. One way around this problem is to use independent RF power sources to drive the inner and outer antennas. Since each power supply has its own impedance matching network, impedance imbalance between the inner and outer antennas is not a problem. However, since it is difficult or impractical to keep the two independent power supplies in phase, beneficial and useless interference between the RF fields generated by the two antennas as their RF currents are no longer in phase or out of phase. Occurrence causes another problem that undesirable effects occur. This problem is overcome according to one aspect of the present invention by using a single, novel, dual output RF power supply that has the ability to distribute different RF power levels to its two outputs. However, with this single RF power supply, the imbalance between the impedances of the inner and outer antennas is again a problem. Therefore, it is necessary to facilitate at least equalization of the impedances of the inner and outer coils without sacrificing any inductive coupling.
[0007]
(Summary of Invention)
One embodiment of the present invention is implemented in a plasma reactor for processing semiconductor workpieces. The reactor is an interleaved vacuum chamber with side walls and a ceiling, a workpiece support pedestal generally facing the ceiling, a gas inlet capable of supplying process gas to the chamber, and a solenoid placed on the ceiling. A coil antenna of parallel conductors, and further comprising a first plurality of conductors wound about a symmetry axis substantially perpendicular to the ceiling in each coaxial helical solenoid displaced laterally at least substantially uniformly from axial symmetry. . Each helical solenoid is offset from the other helical solenoid in a direction parallel to the symmetry axis. An RF plasma source power source is connected to both ends of the plurality of conductors.
[0008]
In another embodiment, the antenna is placed on a ceiling and in each of the coaxially arranged helical solenoids, a solenoid comprising a first plurality of conductors wound about an axis of symmetry substantially perpendicular to the ceiling. A segmented parallel conductor coil antenna, each helical solenoid being offset from the other helical solenoid closest in the direction perpendicular to the axis of symmetry by a distance of about the conductor width of the multiple conductors, thereby Helical solenoids have slightly different diameters.
[0009]
In any embodiment, the reactor is further placed on the ceiling, surrounded by a first solenoid interleaved parallel conductor coil antenna and having an inner antenna with a smaller lateral dimension. So that the first parallel conductor coil antenna becomes the outer coil antenna. In one form, the reactor further comprises a second RF plasma source power source connected to the inner coil antenna so that the respective RF power levels supplied to the inner and outer antennas are the inner and outer antennas. Can be adjusted differentially to control the radial distribution of the RF magnetic field supplied from. However, in a preferred embodiment, the RF plasma source power supply has two RF outputs with power levels that can be differentially adjusted, one of the two RF outputs connected to the outer antenna. The other is connected to the inner antenna, so that the respective RF power levels supplied to the inner and outer antennas are different to control the radial distribution of the RF magnetic field supplied from the inner and outer antennas. It can be adjusted dynamically.
[0010]
Preferably, the number of first parallel multi-conductors is greater than the number of second parallel multi-conductors, and accordingly the length of the first parallel multi-conductor is the inductive reactance of the outer antenna and the inner antenna It will be shortened to at least approach it.
[0011]
Also, if the inner antenna is a parallel conductor antenna, preferably, the number of first parallel multiple conductors is greater than the number of second parallel multiple conductors, and the length of the first parallel multiple conductors is: Accordingly, the length of the first parallel multiple conductors is shortened so that the inductive reactance of the outer antenna is at least close to the inductive reactance of the inner antenna.
[0012]
The lateral displacement of the first multiple conductors of the outer antenna is preferably uniform, and the lateral displacement of the second multiple conductors of the inner antenna is preferably uniform, thereby The inner and outer antennas are confined within each narrow annulus with a width corresponding to the thickness of the conductor, thereby maximizing the effect of the difference between the inner and outer antennas on the radial distribution of the supplied RF field. To do.
[0013]
(Detailed description of preferred embodiments)
Solenoid interleaved coil antenna
Referring to FIG. 1, the efficiency of inductive coupling to the plasma is increased by configuring the antenna 100 as a solenoid multi-conductor interleaved coil antenna. In the illustrated embodiment, the solenoid antenna 100 defines a vertical straight cylinder, or virtual cylindrical surface or position, whose axis of symmetry coincides with the axis of symmetry of the vacuum chamber 101 of the reactor. Preferably, furthermore, it coincides with the axis of symmetry of the workpiece received for processing. In FIG. 1, the reactor chamber 101 is defined by a cylindrical side wall 105 and a flat ceiling 110. The wafer support pedestal 115 is provided in the reactor chamber 101 and is directed toward the chamber ceiling and is centered on the axis of symmetry of the chamber. A vacuum pump 120 is connected to the exhaust outlet of the chamber. The process gas supply source 125 supplies process gas into the reactor chamber via the gas inlet 130. The process gas can include, for example, a halide gas for polysilicon etching, a fluorocarbon gas for silicon dioxide etching, or a silane for chemical vapor deposition of silicon. Alternatively, the gas can include, for example, a chlorine-containing gas for metal etching. The gas inlet 130 is shown in FIG. 1 as a single pipe, but in practice it is realized through a more sophisticated structure, such as multiple inlets.
[0014]
Under the influence of RF power induced from the antenna to the chamber, these gases support the plasma for processing the workpiece. The plasma process performed may include not only etching but also deposition using a suitable precursor gas, such as chemical vapor deposition.
[0015]
The pedestal 115 has a conductive electrode 115a that is coupled to a bias RF power source 145 via an impedance matching network 140. The chamber sidewall 105 can be a metal such as aluminum, while the ceiling 110 can be a dielectric such as quartz. In other embodiments of the present invention, the ceiling is not flat and can be dome-shaped or conical. Furthermore, the ceiling 110 may be a semiconductor other than a dielectric. The semiconductor material of the ceiling has an optimal conductivity so that it acts as a window against the RF inductive magnetic field from the electrodes as well as the antenna. To determine the optimum conductivity for this purpose, the method of “Parallel Plate Electrode Plasma Reactor Having An Inductive Antenna Coupling Power Through a Parallel Plate Electrode with a parallel power electrode through a parallel plate electrode” Kenneth S. under the name of “reactor”. U.S. Pat. No. 6,077,384 issued to Collins and issued June 20, 2000. In this case, the ceiling 100 is used as an electrode, but it can be grounded (shown in dotted lines) or connected to the RF power source 155 via the matching network 150 (similarly , Indicated by dotted lines). The chamber and / or antenna may have a shape other than a cylindrical shape, for example, it may be rectangular or have a square cross section. The workpieces may also have a shape other than circular, for example, they may be square or other external shapes. The workpieces to be processed may be semiconductor wafers or they may be other things such as mask reticles.
[0016]
Interleaved solenoid coil antenna 100 can include any number of interleaved conductors. In the embodiment of FIG. 1, the coil antenna consists of three interleaved symmetrically arranged conductors 160, 163, 166. The multiple conductors of the antenna are placed along respective helical paths that are substantially parallel to each other. Each helix forms a solenoid configuration according to the same virtual upright cylindrical surface. As shown, the helical conductors 160, 163, 166 are uniformly spaced from each other in the vertical direction. More generally, the conductors are substantially evenly spaced from one another in the direction of the chamber's approximately axis of symmetry. These power input taps 160a, 163a, 166a are connected to the RF plasma source power source 175 via the impedance matching network 170, respectively. These return taps 160b, 163b, 166b are connected (grounded) to the ground, respectively. As shown, the power (input) taps 160a, 163a, 166a are preferably in the same horizontal plane of the virtual circle and are arranged along the circumference of the virtual circle with uniform spacing and three conductors. In the case of, it is 120 degrees. More generally, the aforementioned planes cross the axis of symmetry of the chamber. Similarly, the return taps 160b, 163b, 166b are on the same plane and are arranged at a uniform interval. In this embodiment, the helical path of each conductor 160, 163, 166 has taps 160a, 163a, 166a in the same plane, but is sufficient in the axial direction to achieve a substantially uniform axial displacement between the conductors. It has a gentle slope. In other embodiments, the taps need not be in the same plane.
[0017]
In the embodiment of FIG. 1, the power and return taps of each conductor are axially aligned (here, since the chamber axis is shown to be vertically oriented, ) For example, the power tap 160a and the return tap 160b of the conductor 160 are aligned in the axial direction. Preferably, the grounded end of the winding is closest to the chamber ceiling, as shown in FIG. 1, to prevent high potentials from approaching the plasma, thereby tending to arc and undesirable capacitance Minimize coupling effects.
[0018]
The main advantage is that inductive coupling is provided by multiple conductors other than a single conductor (e.g., three conductors 160, 163, 166), so that for the same amount of inductive coupling, a short conductor Can be used. This feature greatly reduces the potential drop along each conductor and advantageously reduces capacitive coupling.
[0019]
In this illustrated embodiment, the antenna 100 is symmetrically disposed about the symmetry axis of the cylindrical reactor chamber sidewall 105. Thus, for example, the input taps 160a, 163a, 166a are equally spaced from the symmetry axis of the cylindrical sidewall 105. Similarly, the output (return) taps 100b, 163b, 166b at the bottom of the antenna 100 are equally spaced from the axis of symmetry of the cylindrical side wall 105. Further, each conductor 160, 163, 166 is substantially the same shape and substantially the same length spaced substantially the same distance from each other about the axis of symmetry. Preferably, the input and output taps of each conductor (eg, input and output taps 160a, 160b) are vertically aligned with each other (ie, along the axis of symmetry of cylindrical sidewall 105).
[0020]
Why solenoid coils give good coupling
The solenoid feature of the illustrated embodiment of the present invention increases the coupling of the antenna to the plasma because each conductor segment is spaced from its nearest neighbor conductor segment in the direction of the axis of symmetry. In this way, the magnetic field lines contributing to the mutual coupling between the conductor segments are axial, so that they effectively reach the plasma in the reactor chamber. Thus, the coupling to the plasma is increased compared to a flat design where the coils have mutual coupling in the direction perpendicular to the chamber axis. In the embodiment of FIG. 1, the three conductors 160, 136, 166 are axially separated from each other so that the mutual inductance between the nearest neighboring conductors is generally in the axial direction of the chamber.
[0021]
Inner and outer solenoid coil antennas with multiple interleaved conductors
FIGS. 2-4 show a perspective view, top view and longitudinal section of a reactor having inner and outer solenoid antennas, each antenna having a number of interleaved conductors of the type shown in FIG. The inner solenoidal antenna 210 has two interleaved conductors 215, 220 (different from the three shown in FIG. 1). However, in other embodiments, a greater number of conductors may be provided than these interleaved conductors. The power taps (terminals) 215a and 220a are arranged 180 degrees apart from each other, and the return taps 215b and 220b are the same. As in the embodiment of FIG. 1, the power and return terminals of each conductor 215, 220 of FIG. 2 are vertically aligned. In other embodiments, they may not be axially aligned. Also, as in the embodiment of FIG. 1, in FIG. 2, the power taps 215a, 220a are on the upper surface across the axis, while the return taps 215b, 220b are on the lower surface across the axis. In the position shown, both of these crossed surfaces are horizontal. Each of the conductors 215, 220 is wound in a helix with sufficient slope, and the 180 degree angular separation of the power taps 215a, 220a is the axis between the conductors 215, 220 shown in FIG. Sufficient to provide a directional offset.
[0022]
The outer antenna 230 has three interleaved parallel conductors 235, 240, 245 having power taps 235a, 240a, 245a spaced 120 degrees in the upper horizontal plane and return taps 235b, 240b, 245b spaced 120 degrees in the lower horizontal plane. doing. In order to facilitate adjustment of the radial distribution of plasma ion density, the power level supplied to each one of the inner and outer antennas 210, 230 must be adjustable separately or operatively. For this purpose, FIG. 2 shows two separate RF power sources 250, 255 coupled to the inner and outer antennas 210, 230 via respective impedance matching networks 260, 265. One problem with using separate power supplies is that their output signals tend to wander in phase and out of phase. Instead, FIG. 4 shows a common RF power supply 270 having two differentially adjustable outputs connected to the inner and outer antennas 210, 230. Dual output RF power supply 270 is described later in this document. Its main advantage is that the separately adjustable RF signals supplied to the inner and outer antennas 210, 230 are in phase, but their respective power levels can be adjusted with respect to each other. The innovative design of the multi-coil antenna facilitates impedance matching and balancing between multiple coils and the use of a common power source.
[0023]
The elevational cross section of FIG. 4 shows how the individual radial shapes of the inner and outer antennas 210, 230 are in a small area of the ceiling 110, with the remaining area above most of the ceiling. It provides enough space for the placement of temperature control elements. In particular, for example, the temperature control element can have thermal conductive spacers 286, 288 in contact with the top surface of the ceiling 110 in portions not under the inner and outer antennas 210, 230. The inner spacer 286 is an upright solid cylinder surrounded by the inner antenna 210, while the outer spacer is a solid annulus surrounded by the inner and outer antennas 210, 230. A cooling plate 290 is placed in contact with the top surfaces of the heat transfer spacers 286 and 288 and has a cooling passage 292 through which a cooling liquid extending through the cooling plate circulates. In addition, the spacers 286, 288 may have a hollow space for facing the ceiling 110 to accommodate the heating lamp 294.
[0024]
Inside of solenoid / How the outer antenna increases the adjustment of the radial distribution of plasma ion density
Flat (“pancake-like”) type inner and outer antennas will be distributed across a relatively large horizontal annulus, so the “location” of their radiated power deposition is individually defined It has not been. For example, some of the outer windings of the inner antenna are near the inner winding of the outer antenna. Accordingly, these RF currents flowing in the outermost winding of the inner antenna affect the coupling of the inner winding of the outer antenna. Similarly, the RF current flowing in the innermost winding of the outer antenna affects the coupling of the outer winding of the inner antenna. As a result, the positional effects of the inner and outer antennas are diffused and the radial power distribution cannot be easily controlled by simply adjusting the RF power supplied to the solenoid coil. This can shift the radial distribution of the RF field (and hence the radial distribution of the plasma ion density) for the differences provided between the power levels supplied to the inner and outer antennas. Decrease degree.
[0025]
Conversely, in the embodiment shown in FIGS. 2-4, the inner and outer antennas 210 of the solenoids in which the multiple conductors are offset from each other in a substantially vertical direction (ie, more generally in the direction of the chamber axis). , 230 does not actually have a radial width that exceeds the radial width of the thin conductor itself. This clearly shows that in the horizontal plane (ie, more generally the plane across the chamber axis), the inner and outer antennas 210, 230 appear as two individual concentric circles with a thin circular line. This is best seen in the embodiment of FIG. Thus, for example, all of the RF power supplied to the outer antenna 230 radiates into the chamber from a single individual radial position of the outer antenna and is wasted at the internal radial position as in the conventional antenna described above. There is nothing to do. This is also true for the inner antenna in that all of the RF power supplied to the inner antenna 210 radiates from a single individual radius of the inner antenna 210. Thus, it is not wasted at the outer radial position. As a result, for a given range of differences in the supplied power levels of the inner and outer antennas 210, 230, the shift in the radial distribution of plasma ion density can be much greater than in the conventional case. Understood.
[0026]
This feature provides significant advantages as the chamber size is increased upwards to accommodate larger semiconductor wafer sizes. As the size of the wafer increases, it becomes difficult to maintain a uniform plasma ion density across the entire wafer surface and to adjust the distribution of plasma ion density across the wafer surface. The radial distribution of plasma ion density is largely determined by the radial distribution of a given induced magnetic field. Therefore, the radial distribution of the plasma ion density can be easily formed by adjusting the radial distribution of the induced magnetic field provided from the overhead antenna. As the size of the wafer increases, a greater ability to create or adjust the radial distribution of the applied RF induced magnetic field is needed more than previously possible. This need includes (a) limiting each of the inner and outer antennas to separate or very narrow radial positions, and (b) providing this antenna as a plurality of symmetrically arranged conductors. By increasing the effect of the distribution of the RF power applied between the inner and outer antennas. This not only provides a basis for significantly increased impedance matching and power distribution capabilities of various diameter antennas, but also reduces the effects of voltage drops and undesirable capacitive coupling, as described in detail below. Minimize.
[0027]
How the impedances of the inner and outer antennas are matched
As described hereinabove, the large dimension of the outer antenna 230 is longer than the conductor length of the inner antenna 210 and thus exhibits a large inductive reactance. This creates a problem in maintaining a uniform potential difference across the reactor chamber, and an impedance matching problem if a common RF power source is used. One feature of the present invention solves this problem by adjusting the length and number of multiple conductors of the interleaved coil of the inner antenna as compared to the outer antenna. In particular, the outer conductor is provided as a larger number of each interleaved conductor than the inner conductor. Furthermore, each of the outer conductors is proportionally shorter. The number of interleaved conductors between the inner and outer antennas and the ratio of the conductor lengths are sufficient to reduce the imbalance between the impedances of the inner and outer antennas.
[0028]
Therefore, this problem is solved as one of the features of the present invention by reducing the inductance (length) of each of the conductors in the outer antenna 230. In order to avoid simultaneous reduction of the overall inductive coupling of the outer antenna 230, the number of each conductor is provided in the outer antenna 230 more than in the inner antenna 210. In particular, the inner antenna 210 has only two conductors with taps provided at 180 degrees, whereas the outer antenna 230 is provided every 120 degrees as shown in FIG. 2-4. It has three conductors with a given tap. A larger number of conductors relative to the other antennas increases inductive coupling to compensate for each shorter conductor length. In addition, each of the short conductors exhibits a greatly reduced voltage drop compared to the use of a similar single conductor antenna.
[0029]
First integrated embodiment
FIG. 5 shows a first integrated embodiment with multiple solenoidal overhead antennas, each having a plurality of interleaved conductors. The inner solenoid antenna 510 has a pair of interleaved conductors 515, 520 with power taps 515a, 520a spaced 180 degrees apart. The outer solenoid antenna 525 has four interleaved conductors 530, 535, 540, 545 with power taps 530a, 535a, 540a, 545a at 90 degree intervals relative to the axis of symmetry. Each interleaved conductor is substantially parallel to the remaining conductors of the provided antenna. The inner circular power bus 550 above the inner antenna 510 is connected to the inner antenna power taps 515a, 520a. Similarly, the outer circular power bus 552 is connected to the outer antenna power taps 530a, 535a, 540a, 545a. A set of four arms 560, 562, 564, 566 below the outer antenna 525 and spaced 90 degrees connect each grounded tap to a circular grounded housing 570. Two opposite arms 560, 564 spaced 180 degrees apart are connected to the grounded taps 515b, 520b of the inner antenna, respectively, and to the grounded taps 530b, 545b of the outer antenna. . The remaining two opposite arms 562, 566 are connected to grounded taps 535b, 545b of the outer antenna. For each one of the plurality of antenna conductors given in FIG. 5, the power tap and the grounded tap are axially aligned.
[0030]
Furthermore, the power and ground taps of both inner and outer antennas are collinear and axially aligned. However, other embodiments are possible where they need not be aligned. Multiple conductors and symmetric designs facilitate the use of such aligned taps within and between multiple coils, greatly simplifying the input of RF power to the antenna, Minimize the possibility of crosstalk, stray reactance, and inhomogeneities in the plasma.
[0031]
Segmented and lined solenoid conductors
6A and 6B show a single solenoid conductor coil antenna in which multiple conductors are not interleaved (eg, as in the form shown in FIG. 1), but segmented into parallel conductors 610, 620. FIG. Therefore, a solenoid antenna is formed which is considered to be composed of segmented conductors arranged side by side. The top view of FIG. 6B shows how the segmented conductors are arranged rather than arranged along the axis in the direction of the axis of the chamber, or vertically as shown. Show. As in the interleaved embodiment of a given antenna, the arrayed conductors are arranged symmetrically about an axis along helical paths that are substantially parallel to each other. Since one of the conductors 610, 620 has a slightly larger helical radius than the other, the conductor 610 is an inner segment and the conductor 620 is an outer segment. The aligned conductors 610 and 620 function as a single antenna. Because they are placed close together. For example, in the illustrated embodiment, they are spaced apart by a radial distance that is within about one-twentieth of the thickness of the conductors 610, 620. In some implementations, this distance is as much as thirty times the conductor thickness, or as small as a fraction of the conductor thickness.
[0032]
FIG. 7A shows how a segmented and aligned multi-conductor antenna of two solenoids of the type shown in FIGS. 6A and 6B can be used as the inner and outer instead of the inner and outer antennas of FIG. It shows how. In FIG. 7A, the inner antenna 710 consists of a pair of aligned solenoid conductors 712, 714 having upper power taps 712a, 714a and lower return taps 712b, 714b. The outer antenna 730 consists of four side-by-side solenoid conductors 735, 740, 745, 750, each having a smaller number of conductors than the number of inner antennas 710. Their power taps 735a, 740a, 745a, 750a are at the top and their return taps 735b, 740b, 745b, 750b are at the bottom. The inner and outer antennas 710, 730 are preferably connected to different power output terminals so that their power levels are adjusted differentially. This can be accomplished using separate power supplies or a common power supply with separately or differentially adjustable outputs, as described below.
[0033]
FIG. 7B shows a variation of the embodiment of FIG. 7A, where the reactor chamber ceiling, which is different from the flat as in the embodiment of FIG. 7A, is dome-shaped, and the segmented solenoid inner and outer antennas are It is along the dome-shaped ceiling 110 of FIG. 7B. Thus, each solenoidal coil 712, 714 of the inner antenna 710 and each solenoidal coil 735, 740 of the outer antenna 730 are wound in a conical helix or helical dome shape, with each lower winding. The wires 712, 714, 735, 740 have a larger diameter than the upper winding of the coil. Preferably, the conical surface before the coils 712, 714, 735, 740 are wound coincides with the dome-shaped ceiling 110 of FIG. 7B.
[0034]
Tuning the inner and outer flat coil antennas
FIG. 8 shows how the flat form of the inner and outer interleaved coil antennas can be modified to tune the antennas to bring their impedances closer to matching. As in the embodiment of FIG. 5, the inner antenna of FIG. 8 has two interleaved conductors 815, 820, while the outer antenna 825 has four interleaved conductors 830, 835, 840, 845. have. The power taps 815a and 820a of the inner antenna are connected in common, while the ground taps 815b and 820b are provided at an interval of 180 degrees. Outer antenna power taps 830a, 835a, 840a, 845a are provided at 90 degree intervals, and outer antenna ground taps 830b, 835b, 840b, 845b are also provided at 90 degree intervals. As in the embodiment of FIG. 5, the inner and outer antennas of FIG. 8 are substantially impedance matched. This is because the outer antenna is provided twice as many as the individual conductors as the inner antenna, so that its length reduces their respective inductance without sacrificing the overall inductive coupling of the outer antenna. This is because it is shortened in proportion to.
[0035]
As noted above, good impedance matching between the inner and outer multi-conductor antennas 810, 825 uses a common power source for both antennas, thus providing better coupling of power to the plasma and more practical. Facilitates many desirable benefits including application. Induction with the same principle of improved impedance matching including solenoids and flat shapes, as well as interleaved and segmented ones, including multiple antennas each with multiple conductors, regardless of shape It can be applied to sex sources.
[0036]
Solenoid interleaved antenna with dome ceiling
FIG. 9 illustrates how a plasma reactor having a dome-shaped ceiling 110 has the inner and outer antennas 510, 525 of the cylindrical solenoid of FIG. In FIG. 9, the outer antenna 525 is mounted on the outer portion of the dome ceiling and is therefore provided at a somewhat lower level than the inner antenna 510.
[0037]
FIG. 10 shows a variation of FIG. 9 in which the outer antenna 525 is modified to be an antenna that conforms to the slope and substantially vertical surface of the outer portion of the dome-shaped ceiling 110.
[0038]
FIG. 11 shows a variation of FIG. 9 in which the solenoid of the outer winding 525 is modified to be an antenna having an inverted conical partial shape so that the cross section is perpendicular to the surface of the dome-shaped ceiling 110. ing.
[0039]
FIG. 12 shows a variation of FIG. 10 in which the inner antenna 510 has been replaced by a flat interleaved coil antenna 1200 of the type described in the aforementioned patent granted to Qian et al.
[0040]
FIG. 13 shows a variation of FIG. 9 that is placed at the level of the cylindrical side wall 105 of the chamber so that the outer antenna 525 surrounds the side wall 105 of the chamber rather than being placed on the ceiling 110.
[0041]
Solenoid interleaved antenna on a flat ceiling
FIG. 14 shows a modification of FIG. 13 in which the ceiling is flat.
FIG. 15 shows a modification of FIG. 14, in which the inner antenna is the flat interleaved parallel conductor coil antenna 1200 of FIG.
[0042]
Combining interleaving and segmentation
FIG. 16 shows a single solenoidal coil antenna 1600 having both the interleaving described with reference to FIG. 1 and the segmentation described with reference to FIG. 6a. The antenna of FIG. 16 has an inner segment 1605 with two interleaved parallel conductors 1610, 1620. This inner segment 1605 is substantially an example of the two conductors of the interleaved solenoid coil of FIG. The antenna of FIG. 16 further includes an outer segment 1630 that surrounds the inner segment 1605. The outer segment also has two interleaved parallel conductors 1640, 1650. Outer segment 1630 is also an example of the two conductors of the interleaved solenoid coil of FIG. The top ends of each of the conductors in FIG. 16 are power taps, all of which are connected to an RF power source 1670 via an impedance matching network 1660. The lower end of each conductor in FIG. 16 is a return tap connected to the ground.
[0043]
FIG. 17 shows another embodiment of the present invention that is similar to the embodiment of FIG. 5, except that the outer antenna 525 is replaced with the antenna 1600 of FIG. The inner antenna 510 of FIG. 17 is the same as that described with reference to FIG.
[0044]
FIG. 17 is a perspective view giving a detailed view of the antenna 1600 from the longitudinal sectional view of FIG. FIG. 17 illustrates that the power and ground taps 161a, 1610b of the inner segment conductor 1610 are vertically aligned and offset by 180 degrees from the vertically aligned power and ground taps 1620a, 1620b of the other inner antenna conductors 1620 of the inner segment. Indicates that Similarly, the power and ground taps 1640a, 1640b of the outer segment conductor 1640 are vertically aligned and offset by 180 degrees from the vertically aligned power and ground taps 1650a, 1650b of the other conductors 1650 of the outer segment. Indicates that Further, the tap of the inner segment 1605 is disposed at a 90 degree position with respect to the tap of the outer segment 1630.
[0045]
An inner annular power bus 1750 above the inner antenna 510 provides RF power to each of the inner antenna 510 power taps. An outer annular power bus 1760 on both the inner and outer segments 1605, 1630 of the outer antenna provides RF power to each of the power taps of the segments 1605, 1630.
[0046]
RF power supply having a plurality of differentially adjustable outputs
An RF power supply having at least two differentially adjustable power outputs is described earlier in this specification and is entitled “Inductively Coupled Plasma Source with Controllable Power Deposition” April 6, 2000 by Barnes et al. And described in pending US patent application Ser. No. 09 / 544,377. This description is hereby incorporated by reference. FIG. 18 shows one embodiment of such a power supply with dual outputs. In FIG. 18, an RF power source 1800 includes an RF generator 1810 connected to a series capacitor 1820 and a variable parallel capacitor 1825 via an impedance matching network 1815. The first RF output terminal 1830 of the power supply 1800 is connected between the matching network 1815 and the series capacitor 1820, while the second RF output terminal 1840 is connected to the opposite side of the series capacitor 1820. Regulating the variable parallel capacitor 1825, depending on the adjustment, distributes much power to one output terminal or the other output terminal. Therefore, the power levels at the two output terminals can be adjusted differentially. As shown in FIG. 18, the first output terminal 1830 is connected to the inner antenna, while the other output terminal 1840 is connected to the outer antenna of FIG. In FIG. 19, terminals 1830 and 1840 are connected to segmented parallel conductor antennas 710 and 130, respectively, on the inside and outside of FIG. 20, output terminals 1830 and 1840 are connected to interleaved coil antennas 810 and 825 on the inner and outer sides of FIG. 8, respectively. More generally, the dual output power supply of FIG. 18 can be used in any plasma reactor having an inner and outer antenna having a terminal 1830 connected to the inner antenna and a terminal 1840 connected to the outer antenna. This is true for each of the reactors having outer and inner antennas described above with reference to FIGS.
[0047]
The power supply can also have more than two differentially adjustable outputs for use with a reactor having more than two antennas. For example, FIG. 21 shows a reactor having three antennas: an inner antenna 2110, an intermediate antenna 2120, and an outer antenna 2130. Each of these three antennas can be any type of suitable coil antenna, for example, a flat or solenoidal single conductor coil antenna, a flat or solenoidal interleaved parallel conductor antenna, a solenoidal segmented antenna. It may be a parallel conductor antenna, or a combination of the different types described above. However, in the embodiment of FIG. 21, the inner antenna 2110 is the solenoid-like interleaved parallel conductor antenna of FIG. 2, and the intermediate antenna 2120 is the segmented, interleaved parallel conductor antenna 1600 of FIG. . Further, the outer antenna 2130 is a major modification of the segmented and interleaved parallel conductor antenna 1600 of FIG.
[0048]
FIG. 22 shows an RF power supply having three differentially adjustable output terminals for use with three plasma reactors, eg, a plasma reactor with three antennas of FIG. The RF power source of FIG. 22 shows an RF power generator 2210 having a matching network 2215, first and second series capacitors 2220, 2230, and first and second variable parallel capacitors 2240, 2250. The first variable parallel capacitor 2240 is connected to both the first series capacitor and ground, and the second variable parallel capacitor 2250 is connected to both the second series capacitor 2230 and ground. The first output terminal 2260 is connected between the matching network 2215 and the first series capacitor 2220. The second output terminal 2265 is connected between the first parallel capacitor 2240 and the second series capacitor 2230. The third output terminal 2270 is connected to the other side of the second series capacitor 2230. Preferably, the first output terminal 2260 is connected to the power tap of the inner antenna 2110 of FIG. 21, the second output terminal 2265 is connected to the power tap of the intermediate antenna 2110, and the third output terminal 2270 is Connected to the power tap of the outer antenna 2130.
[0049]
FIG. 23 shows a variation of the three-terminal RF power supply of FIG. 22, where the first series and parallel capacitors 2220, 2240 are connected in parallel to the second series and parallel capacitors 2230, 2250.
[0050]
In practice, the variable parallel capacitors 2240, 2250 are tuned to distribute different RF power levels to the inner, middle and outer antennas until the desired radial distribution of the supplied RF magnetic field or plasma ion density is obtained. The The particular radial distribution to be obtained depends on the process being performed. For example, some processes require a uniform distribution. Other processes, such as aluminum etching, produce a non-uniform gas or ion distribution across the wafer surface that is compensated by selecting an appropriate non-uniform radial distribution of the supplied RF magnetic field. This selection is achieved by adjusting variable parallel capacitors 2230, 2250.
[0051]
FIG. 24 shows a variation of the embodiment of FIG. 1, where the coil antenna 100 including the coil conductors 160, 163, 166 is a rectangle with a symmetry axis as opposed to a circle as in the embodiment of FIG. is there. This embodiment is better adapted to handle flat panel displays and the like.
[0052]
Advantages of disclosed embodiments
Many problems in this area that have reduced the performance of plasma reactors have now been solved. The solenoid feature of the present invention increases the efficiency of the antenna because each conductor segment is replaced by its nearest neighbor conductor segment in a substantially axial direction. In this way, the magnetic field lines that can contribute to the mutual coupling between the conductor segments are in the vertical direction, so that they advantageously reach the plasma in the reactor chamber. Thus, the coupling to the plasma is increased for a flat design where the coils are interconnected in a direction perpendicular to the chamber axis.
[0053]
The vertical solenoid interleaved multi-conductor inner and outer antennas have almost no radial width beyond the width of the thin conductor itself. Thus, for example, most of the RF power supplied to the outer antenna radiates into the chamber from a single individual radius of the outer antenna, thus “wasting” at the internal radial position as in the conventional antenna described above. “No. This is true for the inner antenna in that the majority of the RF electrodes supplied to the inner antenna radiate from a single individual radius of the inner antenna. Thus, it is not wasted at the outer radial position. As a result, for a given range of differences in power levels supplied for the inner and outer antennas, a much greater shift in the radial distribution of plasma ion density than is possible in the past is achieved. .
[0054]
This feature of the present invention is particularly advantageous in that it provides a uniform and / or tunable plasma ion distribution over a very large wafer surface. Thus, the chamber size can be easily increased to large diameter wafers using the inner and outer antenna structures. Furthermore, by using a very large number of antennas, for example intermediate antennas between the inner and outer antennas, very large ones can be obtained.
[0055]
The problem of imbalance between the impedances of the inner and outer antennas is overcome by adjusting the length and number of multiple conductors in the interleaved coils of the inner and outer antennas. The outer antenna is segmented into a greater number of interleaved conductors than the inner antenna. Furthermore, each conductor of the outer antenna is proportionally shorter. The number of interleaved conductors between the inner and outer antennas and the ratio of the conductor lengths are sufficient to reduce the imbalance between the impedances of the inner and outer antennas. Therefore, this problem is solved by reducing the inductance (length) of each conductor of the outer antenna relative to the inner antenna. To avoid the concomitant reduction in the overall inductive coupling of the outer antenna, much more individual conductors are provided in the outer antenna than the inner antenna. A very large number of individual antennas increases inductive coupling to compensate for the shortened conductor length of the outer antenna. For the inner and outer antennas to be matched or nearly matched, a common power source that drives both antennas can be used without encountering impedance matching problems. The illustrated embodiment of the present invention uses a multiple output common power supply with a differentially adjustable power level that allows adjustment of the radial distribution of plasma ion density.
[0056]
As an alternative to an interleaved multi-conductor antenna, a segmented multi-conductor antenna has the advantages of an interleaved conductor antenna and can be realized in the various shapes described above having a solenoid or dome shape. Further, the segmented shapes can be combined with the interleaved shapes according to the embodiments described above and illustrated.
[0057]
The solenoid interleaved, segmented conductor antenna described above preferably has a common surface power tap on one side (eg, top) and a common surface return tap on the other side (eg, bottom). Have. Advantageously, for each one of the conductors of a given antenna, its power and return taps are vertically aligned (or more generally aligned along the axis of the coil antenna), Therefore, the shape of the antenna can be advantageously simplified.
[0058]
Thus, first, some and indeed all of the aforementioned advantages are provided simultaneously in the same plasma source.
[0059]
Although the invention has been described in detail with particular reference to the illustrated embodiments, it will be understood that modifications and changes can be made without departing from the true spirit and scope of the invention. It should be.
[Brief description of the drawings]
[Figure 1]
1 shows a first embodiment of the present invention having a single solenoid interleaved multi-conductor coil antenna.
[Figure 2]
FIG. 6 shows a perspective view of a second embodiment of the present invention having a multi-conductor coil antenna with interleaved inner and outer solenoids.
[Fig. 3]
FIG. 5 shows a top view of a second embodiment of the present invention having a multi-conductor coil antenna with interleaved inner and outer solenoids.
[Fig. 4]
FIG. 6 shows a cross-sectional view of a second embodiment of the present invention having a multi-conductor coil antenna with interleaved inner and outer solenoids.
[Figure 5]
1 shows a perspective view of a first preferred embodiment of the present invention having an interleaved conductor coil antenna with inner and outer solenoids. FIG.
FIG. 6A
FIG. 6 shows a perspective view of another embodiment of the present invention having a single solenoid segmented multi-conductor coil antenna.
FIG. 6B
FIG. 6 shows a top view of another embodiment of the present invention having a single solenoid segmented multi-conductor coil antenna.
FIG. 7A
Fig. 4 shows another embodiment of the invention with segmented conductor antennas for inner and outer solenoids.
FIG. 7B
FIG. 7B shows a variation of the implementation of the present invention of FIG. 7A where the coil antenna matches the dome shape.
[Fig. 8]
Fig. 4 shows another embodiment of the invention comprising an outer flat interleaved conductor coil antenna, the length of the conductor being tuned to approximately match the impedance of the inner coil antenna.
FIG. 9
FIG. 5 shows one shape of a solenoid, interleaved conductor coil antenna, with a plasma reactor having a dome shaped ceiling of the reactor chamber.
FIG. 10
Fig. 5 shows another shape of a solenoid, interleaved conductor coil antenna, with a plasma reactor having a dome shaped ceiling of the reactor chamber.
FIG. 11
Fig. 5 shows another shape of a solenoid, interleaved conductor coil antenna, with a plasma reactor having a dome shaped ceiling of the reactor chamber.
FIG.
Fig. 5 shows another shape of a solenoid, interleaved conductor coil antenna, with a plasma reactor having a dome shaped ceiling of the reactor chamber.
FIG. 13
Fig. 5 shows yet another shape of a solenoid, interleaved conductor coil antenna, with a plasma reactor having a dome shaped ceiling of the reactor chamber.
FIG. 14
FIG. 5 shows one configuration of a solenoid interleaved multi-conductor coil antenna with a plasma reactor having a flat chamber ceiling.
FIG. 15
Fig. 6 shows another form of solenoid, interleaved multi-conductor coil antenna, along with a plasma reactor with a flat chamber ceiling.
FIG. 16
An embodiment of the present invention which combines interleaving and segmentation of a plurality of conductors in a single solenoid coil antenna will be described.
FIG. 17
FIG. 17 shows a preferred embodiment of the present invention with inner and outer coil antennas, which are solenoid coil antennas of the type shown in FIG. 16 where the outer antenna has interleaved and segmented conductors.
FIG. 18
FIG. 6 shows a single power supply with two differentially adjustable outputs connected respectively to the inner and outer coil antennas of FIG.
FIG. 19
FIG. 19 shows the power supply having the dual output of FIG. 18 connected to the inner and outer coil antennas of FIG.
FIG. 20
FIG. 19 shows the power supply having the dual output of FIG. 18 connected to the inner and outer coil antennas of FIG. 8, respectively.
FIG. 21
Fig. 4 illustrates another embodiment of the present invention having inner, middle and outer solenoidal multi-conductor coil antennas.
FIG. 22
FIG. 22 illustrates a first embodiment of a power supply having a differentially adjustable triple output for use with the reactor of FIG.
FIG. 23
FIG. 22 illustrates a second embodiment of a power supply having a differentially adjustable triple output for use with the reactor of FIG.
FIG. 24
3 shows another embodiment of FIG. 1 in which the coil antenna is a square other than a circle.

Claims (164)

A plasma reactor for use with a supply of RF power to process a workpiece,
A vacuum chamber having a ceiling and defining axial symmetry;
A workpiece support pedestal in the chamber;
A first solenoid interleaved coil antenna placed on at least an intermediate portion of the ceiling and having a first plurality of conductors wound about an axis of symmetry in a respective coaxial helical solenoid;
With
The plurality of conductors are at least substantially uniformly laterally displaced from the symmetry axis, the plurality of conductors are offset from each other in the direction of the symmetry axis, and each of the plurality of conductors is at both ends of the RF source power supply A plasma reactor characterized by being connected. The coil antenna is between an upper surface and a lower surface substantially perpendicular to the axis of symmetry, and a helical solenoid defined by each conductor terminates at an upper point of the conductor near the upper surface and a lower point of the conductor near the lower surface. The plasma reactor according to claim 1, wherein the RF power source is connected to both ends of the upper point and the lower point of each of the conductors. The plasma reactor according to claim 2, wherein the upper point is connected to an output terminal of the RF power source, and the lower point is grounded so as to reduce a potential near the ceiling. The plasma reactor according to claim 2, wherein the upper points are angularly displaced from each other by about 360 / n, where n is the number of the plurality of conductors of the coil antenna. 5. The plasma reactor according to claim 4, wherein the lower points are angularly displaced from each other by about 360 / n, where n is the number of the plurality of conductors of the coil antenna. The plasma reactor according to claim 5, wherein the upper point is on the same plane and on the upper surface. The plasma reactor according to claim 6, wherein the lower point is on the same plane and on the lower surface. The plasma reactor according to claim 7, wherein the lower surface is substantially flush with the upper surface of the ceiling and is on the lower surface. The plasma reactor according to claim 2, wherein the upper end and the lower end of each of the conductors are on the same straight line in a direction parallel to the symmetry axis. The helical conductor of the plurality of conductors is cylindrical, and the lateral extent is the diameter of the helical solenoid, thereby defining an upright cylinder of the coil antenna. Plasma reactor. The plasma reactor of claim 1 further comprising a plasma bias RF power source connected to a support pedestal of the workpiece. The plasma reactor according to claim 1, wherein the plasma source power source includes a source RF generator and an impedance matching network connected between the source RF generator and the antenna. The plasma reactor of claim 1, wherein the plasma bias power source comprises a bias RF generator and an impedance matching network connected between the bias RF generator and a support pedestal of the workpiece. And further comprising an inner coil antenna placed on the ceiling, surrounded by an interleaved conductor coil antenna of the first solenoid and having a smaller lateral extent, whereby the first solenoid The plasma reactor according to claim 1, wherein the interleaved conductor coil antenna is an outer coil antenna. And a second RF plasma source power source connected to the inner coil antenna so that the respective RF power levels supplied to the inner and outer antennas are supplied from the inner and outer antennas. The plasma reactor according to claim 14, wherein the plasma reactor is differentially adjustable to control the radial distribution of the RF magnetic field. The first RF plasma source power supply has two RF outputs having differentially adjustable power levels, one of the two RF outputs being connected to the outer antenna and the other being an inner antenna. So that the respective RF power levels supplied to the inner and outer antennas are differentially adjusted to control the radial distribution of the RF magnetic field supplied from the inner and outer antennas. A plasma reactor characterized in that it is possible. The number of the first plurality of conductors is greater than the number of the second plurality of conductors, and the length of the first plurality of conductors accordingly sets the inductive reactance of the outer antenna to that of the inner antenna. The plasma reactor according to claim 14, wherein the plasma reactor is shortened to at least approach the reactance. The inner antenna is placed on the ceiling and wound about the symmetry axis of a coaxial helical solenoid that is at least substantially uniform laterally displaced from the symmetry axis, less than the displacement of the outer antenna. A second solenoid interleaved conductor coil antenna having two conductors, wherein each helical solenoid conductor is offset from a conductor of another helical solenoid in a direction parallel to the axis of symmetry. The plasma reactor according to claim 14. The plasma reactor according to claim 18, wherein the number of the first plurality of conductors of the outer antenna is larger than the number of the second plurality of conductors of the inner antenna. The number of the first parallel multiple conductors is greater than the number of the second parallel multiple conductors, and the length of the first parallel multiple conductors accordingly sets the inductive reactance of the outer antenna to the inner antenna. 20. The plasma reactor of claim 19, wherein the plasma reactor is shortened to be at least close to the inductive reactance of the. 21. The plasma reactor according to claim 20, wherein the number of the second plurality of conductors is sufficient to compensate for the short length. The plasma reactor according to claim 21, wherein the number of the first plurality of conductors is twice the number of the second plurality of conductors. The lateral displacement of the first plurality of conductors of the outer antenna is uniform, and the lateral displacement of the second plurality of conductors of the inner antenna is uniform, whereby the inner and outer antennas are uniform. Is limited to within each narrow annular width corresponding to the thickness of the conductor, thereby minimizing the effect of the radial inner and outer differences of the supplied RF field. The plasma reactor according to claim 18. The plasma reactor according to claim 23, wherein the chamber and the inner and outer antennas are cylindrical. 25. The reactor chamber of claim 24, wherein the lateral displacements of the first and second multiple conductors are outer and inner radii, respectively, and are above and around the chamber and the central region, respectively. . The inner coil antenna is between an upper inner surface and a lower inner surface substantially perpendicular to the axis of symmetry, and a helical solenoid defined by each conductor of the inner antenna is at the upper point of the conductor near the upper inner surface and the lower The outer coil antenna terminates at a lower point of the conductor near the inner surface, and the outer coil antenna is between the upper outer surface and the lower outer surface substantially perpendicular to the axis of symmetry, and the helical solenoid defined by each conductor of the outer antenna is 19. The plasma reactor according to claim 18, wherein the plasma reactor terminates at an upper point of the conductor near the upper outer surface and at a lower point of the conductor near the lower outer surface. The upper point of the outer antenna is angularly displaced from each other by about 360 / n, where n is the number of conductors of the outer coil antenna, and the upper point of the inner antenna is m equal to the inner coil 27. The plasma reactor according to claim 26, wherein the number of antennas is angularly displaced from each other by about 360 / n when the number is the number of conductors of the antenna. The lower point of the outer antenna is angularly displaced from each other by about 360 / n, where n is the number of conductors of the outer coil antenna, and the lower point of the inner antenna is m of the inner coil The number of conductors of the antenna is angularly displaced from each other by about 360 / n, and the upper and lower points of each of the conductors are aligned along a direction parallel to the axis of symmetry. 28. The plasma reactor according to claim 27, wherein: And an inner annular RF power conductor bus having substantially the same radius as the inner antenna on the upper inner surface, wherein the upper point of the inner antenna is connected to the inner annular RF power conductor bus, and An outer annular RF power conductor bus having substantially the same radius as the outer antenna is provided on an upper outer surface, and the upper point of the outer antenna is connected to the outer annular RF power conductor bus. Item 29. The plasma reactor according to Item 28. 28. The plasma reactor according to claim 27, wherein n is an integer multiple of m, and n / m of the upper point of the outer antenna is angularly aligned with the upper point of the antenna. . 3. The plasma reactor according to claim 2, wherein the upper point and the lower point are equally spaced with respect to the axial symmetry of the reactor. 32. The plasma reactor according to claim 31, wherein the conductors are about the axis of symmetry of the reactor and are equally spaced and substantially the same shape. The plasma reactor according to claim 1, wherein the antenna conductors are substantially parallel to each other. The plasma reactor according to claim 1, wherein the solenoid antenna is rectangular. 3. The plasma reactor according to claim 2, wherein the upper points are equally spaced azimuthally and the lower points are equally spaced azimuthally. The plasma reactor according to claim 2, wherein corresponding points of the upper and lower points are axially aligned. A plasma reactor having an RF source power supply for processing a workpiece,
A vacuum chamber having a ceiling and defining an axis of symmetry;
A workpiece support pedestal in the chamber;
A segmented coil antenna of a first solenoid having a first plurality of conductors wound around an axis of symmetry in a helical solenoid each above a ceiling and coaxially arranged;
Have
Each of the helical solenoid conductors is offset from the other helical solenoid conductor nearest the transverse direction of the symmetry axis by a distance of approximately the conductor width of the plurality of conductors, each of the conductors being A plasma reactor adapted to connect to both ends of an RF source power supply. 38. The plasma reactor of claim 37, wherein each helical solenoid of the antenna has a slightly different diameter. 38. The plasma reactor according to claim 37, wherein each of the segmented conductors of the antenna is substantially parallel to each other. The coil antenna is between an upper surface and a lower surface that are substantially perpendicular to the symmetry axis, and the helical solenoid defined by each conductor is at the upper point of the conductor near the upper surface and the conductor near the lower surface. 38. The plasma reactor according to claim 37, wherein the RF power source is connected to both ends of the upper point and the lower point of each of the conductors. The plasma reactor according to claim 40, wherein the upper point is connected to an output terminal of the RF power source, and the lower point is grounded so as to reduce a potential near the ceiling. 41. The plasma reactor according to claim 40, wherein the upper points are angularly displaced from each other by about 360 / n, where n is the number of the plurality of conductors of the coil antenna. 41. The plasma reactor according to claim 40, wherein the lower points are angularly displaced from each other by about 360 / n, where n is the number of the plurality of conductors of the coil antenna. 41. The plasma reactor according to claim 40, wherein the upper point is on the same plane and on the upper surface. 41. The plasma reactor according to claim 40, wherein the lower point is on the same plane and is on the lower surface. The plasma reactor according to claim 45, wherein the lower surface is substantially flush with an upper surface of the ceiling. 41. The plasma reactor according to claim 40, wherein the upper end portion and the lower end portion of each of the conductors are flush with each other in a direction parallel to the axis of symmetry. 38. The helical conductor of the plurality of conductors is cylindrical and the lateral extent is the diameter of the helical solenoid, whereby the coil antenna defines an upright cylindrical shape. Plasma reactor. The plasma reactor of claim 37, further comprising a plasma bias RF power source connected to the workpiece support pedestal. 38. The plasma reactor according to claim 37, wherein the plasma source power source includes a source RF generator and an impedance matching network connected between the source RF generator and the antenna. 50. The plasma reactor of claim 49, wherein the plasma source power source includes a bias RF generator and an impedance matching network connected between the bias RF generator and the workpiece support pedestal. 38. The method according to claim 37, further comprising an inner coil antenna on the ceiling, surrounded by the interleaved parallel conductor coil antenna of the first solenoid and having a smaller lateral extent. Plasma reactor. And a second RF source power source connected to the inner coil antenna so that the respective RF power levels supplied to the inner and outer antennas are RF magnetic fields supplied from the inner and outer antennas. 53. The plasma reactor according to claim 52, wherein the plasma reactor is differentially adjustable to control the radial distribution of the plasma. The first RF plasma source power source includes two RF outputs having differentially adjustable power levels, one of the two RF outputs being connected to the outer antenna and the other being the inner antenna. So that the respective RF power levels supplied to the inner and outer antennas are adjusted differentially to control the radial distribution of the RF magnetic field supplied from the inner and outer antennas. 53. The plasma reactor according to claim 52, which is possible. The number of the first parallel multiple conductors is greater than the number of the second parallel multiple conductors, and thereby the length of the parallel multiple conductors determines the inductive reactance of the outer antenna and the induction of the inner antenna. 53. The plasma reactor according to claim 52, wherein the plasma reactor is shortened to at least approach the sexual reactance. The inner antenna has a second solenoid segmented parallel conductor coil antenna on the ceiling and having a second plurality of conductors wound around the axis of symmetry in a coaxial helical solenoid 53. The plasma reactor according to claim 52, wherein each helical solenoid is offset from another helical solenoid in a direction perpendicular to the axis of symmetry. 57. The plasma reactor according to claim 56, wherein the number of the first plurality of conductors of the outer antenna is greater than the number of the second plurality of conductors of the inner antenna. The number of the first parallel multiple conductors is greater than the number of the second parallel multiple conductors, and thereby the length of the first parallel multiple conductors causes the inductive reactance of the outer antenna to 57. The plasma reactor according to claim 56, wherein the plasma reactor is shortened to at least approximate the inductive reactance of the antenna. 59. The plasma reactor according to claim 58, wherein the number of the second plurality of conductors is sufficient to compensate for the short length. 60. The plasma reactor according to claim 59, wherein the number of the first plurality of conductors is twice the number of the second plurality of conductors. The inner and outer antennas are limited within their narrow annular widths, each limited to the size of the corresponding number of conductors multiplied by the thickness of the conductor, thereby providing a radial direction of the supplied RF magnetic field. 57. The plasma reactor according to claim 56, wherein the influence of the difference between the inner and outer antennas is minimized. 62. The plasma reactor according to claim 61, wherein the chamber and the inner and outer antennas are cylindrical. 63. The plasma reactor of claim 62, wherein the lateral displacements of the first and second plurality of conductors are respective outer and inner radii overlying the periphery and center region, respectively. . The inner coil antenna is between an upper inner surface and a lower inner surface that are substantially perpendicular to the axis of symmetry, and a helical solenoid defined by each conductor of the inner antenna includes an upper point and a lower portion of a conductor near the upper inner surface. Terminated at the lower point of the conductor near the inner surface, and the outer coil antenna is between the upper outer surface and the lower outer surface substantially perpendicular to the symmetry axis, and the helical solenoid defined by each conductor of the outer antenna is 57. The plasma reactor according to claim 56, terminated at an upper point of a conductor near the upper outer surface and at a lower point of the conductor near the lower outer surface. The upper points of the outer antenna are angularly displaced from each other by about 360 / n, where n is the number of the plurality of conductors of the outer coil antenna; and
65. The plasma reactor of claim 64, wherein the upper points of the inner antenna are angularly displaced from each other by about 360 / m, where m is the number of the multiple conductors of the outer coil antenna. . The lower points of the outer antenna are angularly displaced from each other by about 360 / n, where n is the number of the conductors of the outer coil antenna;
The lower points of the inner antenna are angularly displaced from each other by about 360 / m, where m is the number of conductors of the outer coil antenna, and the upper and lower points of each of the conductors are 66. The plasma reactor according to claim 65, wherein the plasma reactor is aligned along a direction parallel to the axis of symmetry. And further comprising an inner annular RF power conductor bus on the upper inner surface and having a radius substantially the same as the radius of the inner antenna, wherein the upper point of the inner antenna is connected to the inner annular RF power conductor bus. And an outer annular RF power conductor bus on the upper outer surface and having a radius substantially the same as the radius of the outer antenna, wherein the upper point of the outer antenna is connected to the outer annular RF power conductor bus. The plasma reactor according to claim 66. 38. The plasma reactor according to claim 37, wherein the helical solenoids of the plurality of conductors are spiral in the lateral direction in addition to the longitudinal direction. The plasma reactor according to claim 68, wherein the helical solenoids of the plurality of conductors define a part of a three-dimensional surface. 70. The plasma reactor according to claim 69, wherein the three-dimensional surface is a part of a dome-shaped surface. The plasma reactor according to claim 70, wherein the ceiling defines a three-dimensional surface, and the three-dimensional surface of the helical solenoid coincides with the three-dimensional surface of the ceiling. 72. The plasma reactor according to claim 71, wherein the ceiling and the helical solenoid coincide with each other in a partial dome shape. 41. The plasma reactor according to claim 40, wherein the upper point and the lower point are equally spaced from each other with respect to an axis of symmetry of the reactor. 74. The plasma reactor according to claim 73, wherein the conductors are uniformly spaced with respect to each other and the axis of symmetry and are substantially the same shape. 38. The plasma reactor according to claim 37, wherein the solenoid antenna is rectangular. 38. The plasma reactor according to claim 37, wherein the solenoid antenna coincides with an upright cylinder. A plasma reactor for processing a workpiece,
A vacuum chamber having a ceiling and defining an axis of symmetry;
A workpiece support pedestal in the chamber;
An outer coil antenna having a first plurality of conductors symmetrically wound about the axis adjacent to the chamber;
An inner coil antenna having a second plurality of conductors symmetrically wound about the axis adjacent to the chamber;
With
The number of said 1st multiple conductors is larger than the number of said 2nd multiple conductors, The plasma reactor characterized by the above-mentioned. 78. The plasma reactor according to claim 77, wherein conductors in each of the plurality of conductors are substantially parallel to each other. 78. The plasma reactor according to claim 77, wherein at least the outer antenna is an interleaved parallel conductor coil antenna. 80. The plasma reactor according to claim 79, wherein at least the outer antenna is flat in a plane substantially parallel to the surface of the ceiling. 80. The plasma reactor according to claim 79, wherein at least the outer antenna has a dome shape. 80. The plasma reactor according to claim 79, wherein at least the outer antenna is a solenoid. 78. The plasma reactor of claim 77, wherein at least the outer antenna is a solenoid segmented parallel conductor coil antenna. In addition, each has independent RF plasma source power sources connected to the inner and outer coil antennas, whereby the respective RF power levels supplied to the inner and outer antennas are supplied from the inner and outer antennas. 78. The plasma reactor of claim 77, wherein the plasma reactor is operatively adjustable to control the radial distribution of the RF magnetic field. And an RF plasma source power supply with two RF outputs having differentially adjustable power levels, one of the two RF outputs being connected to the outer antenna and the other being connected to the inner antenna. , Whereby the respective RF power levels supplied to the inner and outer antennas are operatively adjustable to control the radial distribution of the RF magnetic field supplied from the inner and outer antennas. The plasma reactor according to claim 77. The RF plasma source power supply is
An RF power generator having an output terminal and a return terminal;
A series capacitor;
An impedance matching element connected between the output terminal of the RF power generator and one side of the series capacitor;
A variable parallel capacitor connected between the other side of the series capacitor and the return terminal;
A first output node connected to a connection point between the impedance matching element and the series capacitor;
A second output node connected to a connection point between the series capacitor and the variable parallel capacitor;
The plasma reactor according to claim 85, wherein: 86. The plasma reactor of claim 85, further comprising an intermediate coil antenna between the inner and outer antennas, wherein the RF source power source has a third differentially adjustable RF output. The RF plasma source power supply is
An RF power generator having an output terminal and a return terminal;
A first series capacitor;
An impedance matching element connected between the output terminal of the RF power generator and one side of the series capacitor;
A first variable parallel capacitor connected between the other side of the series capacitor and the return terminal;
A second series capacitor having one side connected to a connection point between the first series capacitor and the first parallel capacitor;
A second variable parallel capacitor connected between the other side of the second series capacitor and the RF return terminal;
A first output node connected to a connection point between the impedance matching element and the first series capacitor;
A second output node connected to a connection point between the first series capacitor and the first variable parallel capacitor;
A third output node connected to a connection point between the second series capacitor and the second variable parallel capacitor;
The plasma reactor according to claim 85, wherein: 78. The plasma reactor according to claim 77, wherein the inner and outer antennas are circular. 78. The plasma reactor according to claim 77, wherein the inner and outer antennas are rectangular. 78. The plasma reactor according to claim 77, wherein the inner antenna is on at least an intermediate part of the ceiling. 78. The plasma reactor according to claim 77, further comprising a process gas distribution inlet for supplying process gas to the chamber. 78. The plasma reactor of claim 77, wherein at least one of the inner and outer antennas is a segmented multi-conductor antenna. 78. The plasma reactor according to claim 77, wherein the length of the first parallel multiple conductors is shortened so that the inductive reactance of the outer antenna is at least close to the inductive reactance of the inner antenna. 78. The plasma reactor according to claim 77, wherein the inner antenna is on at least an intermediate part of the ceiling. 78. The plasma reactor according to claim 77, wherein the workpiece support substantially faces the ceiling. 78. The plasma reactor according to claim 77, wherein the outer antenna has a radius larger than that of the inner antenna. Each conductor defines two ends, and the ends of the first plurality of conductors are axially aligned with respective ends of the second plurality of conductors. 77. The plasma reactor according to 77. Each conductor defines first and second ends, and at least the first ends of the first plurality of conductors are equally spaced azimuthally and the at least the first 78. The plasma reactor according to claim 77, wherein the second ends of the plurality of conductors are equally spaced azimuthally. 78. The plasma reactor of claim 77, wherein at least one of the inner and outer antennas defines an upright cylinder. A coil antenna for radiating RF power to a vacuum chamber,
A plurality of parallel segmented conductors, each having a first end and a second end, wherein the first end is connected to a first common RF potential; And wherein the second end is adapted to be connected to a second common RF potential, each of the plurality of conductors being wound around a common axis of symmetry and the second end Each of which is substantially equally spaced from the axis. 102. The antenna of claim 101, wherein each segmented conductor coincides with an upstanding circular cylinder surface. Each of the conductors defines a first and a second end, each of the first ends being azimuthally substantially equally spaced from each other, and each of the second ends is 102. The antenna of claim 101, wherein the antennas are substantially equally spaced from one another. 102. The antenna of claim 101, wherein the plurality of segmented conductors define adjacent coaxial helices each oriented side by side with respect to the axis. 105. The antenna of claim 104, wherein each of the coaxial helices is offset by about a conductor width in the transverse direction of the axis with respect to the other. 102. The antenna according to claim 101, wherein each of the coaxial helices is wound at a pitch having a component in the axial direction. 102. The antenna of claim 101, wherein the first ends are substantially equally spaced from the axis. 102. The antenna of claim 101, wherein each of the conductors is substantially the same length. 102. The antenna of claim 101, wherein the spacing between conductors is substantially the same. 110. The antenna of claim 109, wherein a distance between conductors increases with distance from the axis. 110. The antenna of claim 109, wherein the distance between the conductors is substantially the same over their length. 112. The antenna of claim 111, wherein each of the conductors coincides with a substantially flat surface. 113. The antenna of claim 112, wherein each of the conductors coincides with a circularly symmetric surface. 114. The antenna of claim 113, wherein each of the conductors coincides with a flat circular symmetry plane. 114. The antenna of claim 113, wherein each of the conductors coincides with a dome-shaped circular symmetry plane. 114. The antenna of claim 113, wherein each of the conductors coincides with a curved upright circular cylinder surface. The antenna is adapted to operate with an RF source that provides the first and second potentials, and the first and second ends cross the RF source, respectively, with the first and second ends. 102. The antenna of claim 101, connected to a potential of two. 102. The antenna of claim 101, wherein the first ends are on a common plane. 102. The antenna of claim 101, wherein the second ends are on a common plane. The first end is on a first common surface, the second end is on a second common surface, and the first and second surfaces are parallel. 102. The antenna of claim 101. 121. The antenna of claim 120, wherein the first and second surfaces are spaced apart from each other in the axial direction. 102. The antenna of claim 101, wherein the first end defines a circular position centered on the axis. 123. The antenna of claim 122, wherein the second end defines a circular position centered on the axis. 102. The antenna of claim 101, wherein the plurality of segmented conductors define adjacent coaxial helices each oriented side by side with respect to the axis. 125. The antenna of claim 124, wherein each of the coaxial helices is offset by about a conductor width in the transverse direction of the axis with respect to the other. 102. The antenna according to claim 101, wherein each of the coaxial helices is wound at a pitch having a component in the axial direction. An antenna for radiating RF power to a vacuum chamber,
A plurality of parallel segmented conductors, each having a first end located in the first common region and a second end located in the second common region, each of which Is wound around a common axis through both regions, the region is coaxial with the axis, the conductors are substantially the same length, substantially the same shape, and the common axis An antenna characterized in that it is spaced substantially uniformly around each other. 128. The antenna of claim 127, wherein the second common region is outside the first common region with respect to the axis. 129. The antenna of claim 128, wherein the first and second common areas are axially displaced from each other. 131. The antenna of claim 129, wherein the first and second common areas overlap. 131. The antenna of claim 129, wherein one of the regions is outside the other with respect to the axis. 128. The antenna of claim 127, wherein at least one of the common regions is orthogonal to the axis. 128. The antenna of claim 127, wherein the first and second common regions are on respective planes parallel to each other. 128. The antenna of claim 127, wherein the first and second regions are in the same plane. 128. The antenna of claim 127, wherein the distance between adjacent conductors increases with distance from the common axis. 128. The antenna of claim 127, wherein the distance between adjacent conductors is kept substantially the same over their length. 102. The antenna of claim 101, wherein the first end is axially aligned with one of each of the second ends. 102. The antenna of claim 101, wherein the conductor is rectangular. An antenna for radiating RF power to a vacuum chamber,
A plurality of parallel segmented conductors, each having a first end located in the first common region and a second end located in the second common region, each of which Is wound around a common axis through both regions, the region is coaxial with the axis, the conductors are substantially the same length, substantially the same shape, and the common axis An antenna characterized in that it is spaced substantially uniformly around each other. 140. The antenna of claim 139, wherein the plurality of segmented conductors define adjacent coaxial helices that are each oriented side by side with respect to the axis. 141. The antenna of claim 140, wherein each of the coaxial helices is offset with respect to the other by about a conductor width in a direction across the axis. 140. The antenna of claim 139, wherein the coaxial helix is wound at a pitch having an axial component. 131. The antenna of claim 129, wherein the second common region is outside the first common region with respect to the axis. 128. The antenna of claim 127, wherein the first and second common areas are axially displaced from each other. 145. The antenna of claim 144, wherein the first and second common areas overlap. 144. The antenna of claim 144, wherein one of the regions is outside the other with respect to the common axis. 140. The antenna of claim 139, wherein at least one of the common axes is orthogonal to the common axis. 140. The antenna of claim 139, wherein the first and second common regions are on respective planes parallel to each other. 140. The antenna of claim 139, wherein the first and second regions are in the same plane. 128. The antenna of claim 127, wherein the distance between adjacent conductors increases with distance from the common axis. 128. The antenna of claim 127, wherein the distance between adjacent conductors is kept substantially the same over their length. An RF plasma reactor for processing a workpiece, comprising:
A vacuum chamber having a ceiling and defining an axis of symmetry;
A workpiece support pedestal in the chamber;
An outer coil antenna on the peripheral area of the ceiling;
An inner coil antenna on the inner area of the ceiling;
With
The outer coil antennas each have a first plurality of conductors wound around the axis of a coaxial helical solenoid, each of which is adapted to receive RF power, and the inner coil antennas are respectively A plasma reactor comprising a second plurality of conductors wound about said axis of a coaxial helical solenoid, each of which is adapted to receive RF power. 153. The plasma reactor according to claim 152, wherein the conductors of each antenna are substantially parallel to each other. 153. The plasma reactor according to claim 152, wherein the conductor of each antenna is interleaved. 153. The plasma reactor according to claim 152, wherein the helical solenoids are offset from each other in the direction of the axis. 153. The plasma reactor of claim 152, wherein each helical solenoid is offset with respect to the other by a distance of about the conductor width. 153. The plasma reactor according to claim 152, wherein the conductors of each antenna have approximately the same length and approximately the same shape. 153. The plasma reactor according to claim 152, further comprising an RF power source connected to both ends of each of the conductors. Each antenna conductor defines a first end and a second end, wherein each of the first end and the second end is azimuthally spaced substantially equal to each other. 153. The plasma reactor according to claim 152, wherein: 160. The plasma reactor according to claim 159, wherein the first end and the second end of the antenna are aligned with each other in the axial direction. 157. The plasma reactor according to claim 156, wherein each helical solenoid is wound at a pitch having an axial component. 156. The first end and the second end of the inner antenna are axially aligned with the first end and the second end of the outer antenna, respectively. A plasma reactor according to 1. 153. The plasma reactor of claim 152, wherein the outer antenna has a radius that is greater than a radius of the inner antenna. 140. The antenna of claim 139, wherein the conductor has a rectangular pattern.

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