KR101251930B1 - Apparatus and method for generating Inductively Coupled Plasma - Google Patents

Abstract

The field enhanced inductively coupled plasma processing apparatus includes a process chamber having a dielectric lead and a plasma source assembly disposed over the dielectric lead. The plasma source assembly includes at least one horizontal induction coil configured to inductively couple RF energy into the process chamber to form and maintain a plasma in the process chamber, and to the horizontal induction coil to capacitively couple RF energy into the process chamber. At least one power applying electrode electrically connected, a first positioning mechanism coupled to the power applying electrode to change a horizontal position of the power applying electrode, and an RF generator coupled to the at least one power applying electrode .
In certain embodiments, a field enhanced inductively coupled plasma processing apparatus includes a vertical induction coil connected to a horizontal induction coil and disposed on a side of a dielectric lead, and an agent that moves the vertical position of the vertical induction coil as a whole or changes the spacing of the vertical induction coil. It further comprises a two-position adjustment mechanism.

Description

Field-reinforced inductively coupled plasma processing apparatus and plasma forming method {Apparatus and method for generating Inductively Coupled Plasma}

Embodiments of the present invention relate to semiconductor processing equipment, and more particularly, to an inductively coupled plasma processing apparatus and a plasma forming method.

Inductively coupled plasma (ICP) process reactors generally form a plasma by directing current into a process gas disposed within the process chamber via one or more induction coils disposed outside the process chamber. The induction coil can be disposed out of the chamber and electrically separated, for example, by a dielectric lead. For certain plasma processes, heater elements may be placed over the dielectric leads to facilitate constant temperature maintenance within the chamber during and between processes.

The heater may be an open break heater (eg a non-closed electric loop) or a no break heater (eg a closed electric loop). In embodiments where the heater element is an open disconnected heater element, the heater element introduces a plasma non-uniformity, which may result in asymmetry, for example, in the non-uniform etch rate or etch pattern of the substrate being processed. Such plasma nonuniformity can be eliminated by replacing the open disconnect heater element with a non disconnect heater element.

RF energy delivered to the induction coil is also inductively coupled to the non-interruptible heater element, which undesirably reduces the energy available to form a plasma in the process chamber (e.g., Reduce the plasma strike window).

Thus, there is a need for an improved inductively coupled plasma reactor.

Embodiments of a field enhanced inductively coupled plasma processing apparatus and plasma forming method are provided.

In certain embodiments, a field enhanced inductively coupled plasma processing apparatus includes a process chamber having a dielectric lead and a plasma source assembly disposed over the dielectric lead. The plasma source assembly includes at least one horizontal induction coil configured to inductively couple RF energy into the process chamber to form and maintain a plasma in the process chamber, and to the horizontal induction coil to capacitively couple RF energy into the process chamber. At least one power applying electrode electrically connected, a first positioning mechanism coupled to the power applying electrode to change a horizontal position of the power applying electrode, and an RF generator coupled to the at least one power applying electrode .

In certain embodiments, a field enhanced inductively coupled plasma processing apparatus includes a vertical induction coil connected to a horizontal induction coil and disposed on a side of a dielectric lead, and an agent that moves the vertical position of the vertical induction coil as a whole or changes the spacing of the vertical induction coil. It further comprises a two-position adjustment mechanism.

In certain embodiments, the plasma forming method has at least one horizontal induction coil disposed on the dielectric lead and having at least one vertical induction coil coupled with the horizontal induction coil and electrically connected with the horizontal induction coil. Providing a process gas into an interior volume of a process chamber having at least one power applying electrode; Providing RF power to the power applying electrode from an RF power source; Forming a plasma from the process gas using the RF power inductively capacitively coupled to the process gas by the horizontal induction coil and the vertical induction coil; And controlling at least one of plasma uniformity or ion density by changing at least one of a horizontal position of the power applying electrode, a distance of the horizontal induction coil, a vertical position of the vertical induction coil, and a distance of the vertical induction coil. It includes.

Thus, a field enhanced inductively coupled plasma reactor and methods of use are provided herein. The field enhanced inductively coupled plasma reactor of the present invention advantageously improves the RF power available to collide with the plasma in the chamber without altering other plasma properties, such as plasma uniformity or ion density. The field enhanced inductively coupled plasma reactor of the present invention may further advantageously control and / or adjust plasma properties such as uniformity and / or density during processing.

While the foregoing is directed to embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims.

1 is a schematic side view of a field enhanced inductively coupled plasma reactor in accordance with some embodiments of the present invention;
2 is a schematic plan view of a horizontal induction coil, a vertical induction coil and a power application electrode of a field enhanced inductively coupled plasma reactor in accordance with some embodiments of the invention;
3 is a schematic perspective view of a horizontal induction coil and a vertical induction coil of a field enhanced inductively coupled plasma reactor in accordance with some embodiments of the invention;
4 is a schematic plan view of a heater element of a field enhanced inductively coupled plasma reactor in accordance with some embodiments of the present invention;
5 shows a flow diagram for a method of forming a plasma in accordance with certain embodiments of the present invention.

The inductively coupled plasma reactor according to the present invention can provide increased radio frequency (RF) energy available for impinging the plasma. For example, an improved or enhanced plasma collision window is provided. In addition, the inductively coupled plasma reactor according to the present invention advantageously provides excellent plasma collision performance without substantially altering the uniformity, density or other desirable properties of the plasma.

1 is a schematic side view of a field enhanced inductively coupled plasma reactor 100 in accordance with the same embodiments of the present invention. The field enhanced inductively coupled plasma reactor 100 may be used alone or as an assembly device, such as a semiconductor wafer processing system, as a processing module of an integrated semiconductor substrate processing system. Variations according to embodiments of the present invention include an inductively coupled plasma etch reactor. The semiconductor equipment listed above is merely illustrative and may be modified as appropriate to other etch reactors, CVD reactors that are non-etching reactors, or other semiconductor processing equipment.

The reactor 100 is a process having a conductive body 130 and a dielectric lead 120 that together form a processing volume, a substrate support pedestal 116 disposed within the processing volume, a plasma source assembly 160, and a controller 140. Chamber 110. The conductive body 130 is coupled to the electrical ground 134. Support pedestal (cathode) 116 may be coupled to bias power source 122 via first matching network 124. Although other frequencies and powers may be provided as desired for a particular application, bias power supply 122 may be a power supply up to 1000 W at a frequency of about 13.56 MHz, which may illustratively produce continuous or pulsed power. In another embodiment, the bias power source 122 may be a DC or pulsed DC power supply.

In some embodiments, dielectric lead 120 may be substantially planar. Field enhanced inductively coupled plasma reactor 100 may have, for example, a domed lead or other type of lead. The plasma source assembly 160 is typically disposed above the dielectric lead 120 and configured to inductively couple RF power into the processing chamber 110. The plasma source assembly 160 includes at least one or more horizontal induction coils, at least one or more vertical coils connected to at least one or more horizontal induction coils, at least one or more power applying electrodes, and a plasma power source. At least one horizontal induction coil may be disposed over the dielectric lead 120. At least one vertical induction coil may be connected to the at least one horizontal induction coil and disposed on the side of the dielectric lead 120. As shown in FIG. 1, at least one or more horizontal induction coils 109, 111 disposed over the dielectric lead 120 are illustratively disposed.

Multiple horizontal induction coils 109, 111 are arranged helically, for example. When one end of the first horizontal induction coil 109 is on the left with respect to the center, the other end is located on the right with respect to the center. When one end of the second horizontal induction coil 111 is on the right with respect to the center, the other end is located on the left with respect to the center. At least one or more horizontal induction coils 109 and 111 are arranged in engagement with each other at a predetermined distance. The spacing between the first horizontal induction coil and the second horizontal induction coil, the spacing between the vertical induction coils, the number of windings of each coil may be appropriately selected, for example, to control the density or profile of the plasma.

The first horizontal induction coil 109 and the second horizontal induction coil 111 are coupled to the plasma power source 118 through the matching network 119, respectively. Although other frequencies and powers may be provided as desired for a particular application, the plasma power supply 118 may generate up to 4000 W at frequencies adjustable for example in the range of 50 kHz to 13.56 MHz.

In certain embodiments, power divider 104 may be provided between at least one or more horizontal induction coils to distribute a relative amount of RF power provided by plasma power source 118 to each coil by capacitor coupling. For example, as shown in FIG. 1, the power divider 104 is configured to control the amount of RF power provided to each coil to the plasma power source 118 and the first horizontal induction coil 109 and the second horizontal induction. It may be disposed between the power applying electrode (102, 103) connected to the coil 111, respectively.

At least one of the power applying electrodes 102, 103 is electrically coupled to the first horizontal induction coil 109 or the second horizontal induction coil 111, respectively, for example, as shown in FIG. 1.

RF power may be provided to the first horizontal induction coil and the second horizontal induction coil via the at least one power applying electrode 102, 103 in the plasma power supply 118, respectively.

In certain embodiments, the at least one power applying electrode 102, 103 is movable with one of the at least one horizontal induction coil to facilitate positioning relative to each other and / or relative to the dielectric lead 120. Can be combined. For example, at least one first positioning mechanism (not shown) may be coupled to at least one or more power applying electrodes 102, 103 to change the horizontal position that is connected with the first horizontal induction coil and the second horizontal induction coil. . The first positioning mechanism (not shown) can be a manual or automatic device capable of changing the horizontal positioning of the power applying electrodes 102, 103 including devices including lead screws, linear bearings, stepper motors, wedges, and the like. .

In some embodiments, as shown in FIG. 1, a first positioning mechanism (not shown) is coupled to the power applying electrodes 102, 103, respectively, to independently control the horizontal position of the power applying electrodes 102, 103. Can be.

In certain embodiments, the first position adjustment mechanism (not shown) may change the distance between the first horizontal induction coil 109 and the second horizontal induction coil 111 so as to change the first horizontal induction coil 109 and the second horizontal. It may be coupled to the induction coil 111, respectively.

Independent control of the horizontal position of the power applying electrode and / or control of the spacing between the horizontal induction coils facilitates capacitive coupling of relative RF power to control the density of the plasma and / or the area of the plasma. For example, the closer the horizontal position of the power applying electrode is to the center of the coil, the higher the plasma density, and the larger the distance between the horizontal induction coils, the lower the plasma density, but the plasma area increases.

Control over the amount of capacitive coupling of RF power of the plasma source assembly 160 facilitates control of plasma characteristics in the chamber. For example, capacitive coupling of the plasma source assembly 160 is controlled to vary the plasma impingement window and maintain the desired inductively coupled plasma characteristics. Selective control over the spacing between the horizontal induction coils or the position of the power applying electrode facilitates collision with the plasma without coupling much RF energy into the plasma where a sufficient capacitive coupling has been formed once, thus allowing the characteristics of the plasma (e.g., , Density, dissociation fraction, ion / neutron ratio, etc.) are preferably changed. In addition, this change further facilitates compensation for process effects that can lead to non-uniform plasma, such as non-uniform gas velocity in the chamber by asymmetric gas delivery and / or pumping. For example, by increasing capacitive coupling in regions of low plasma density to regions of higher plasma density, the overall plasma distribution in the chamber can be formed more uniformly, facilitating more uniform processing.

One or more electrodes of plasma source assembly 160 may be disposed symmetrically on top of dielectric lead 120 to promote uniform coupling of RF energy to the plasma. In certain embodiments, one or more electrodes are configured to not provide a continuous path through which current can be induced in one or more electrodes. Thus, in embodiments where a single electrode is used, the electrode may include a dielectric break so that the electrode does not form a conductive annular ring. However, such unusual breaks can lead to plasma non-uniformity by asymmetry in shape. In electrodes where a single electrode is used, dielectric breakdown within the electrode may be positioned to compensate for the natural plasma distribution in the chamber, so as to correspond to a region of relatively high plasma density or close to the pump port of the chamber.

In certain embodiments, two or more horizontal induction coils 109, 111 are disposed in engagement with one another to symmetrically distribute the desired plasma effects generated by the dielectric space. For example, as shown in FIG. 2, there is shown a schematic plan view showing two helical horizontal induction coils 109, 111 and two power applying electrodes 102, 103 spaced at substantially uniform intervals. .

As shown in FIG. 1, the vertical induction coil 113 is connected to at least one of the horizontal induction coils 109 and 111. In certain embodiments, the vertical induction coil 113 may be moved entirely in the vertical direction or vary the spacing therebetween by a second positioning mechanism (not shown). For example, the second positioning mechanism (not shown) may be a manual or automatic device that can change the position or spacing of the vertical induction coil 113, including devices including lead screws, linear bearings, stepper motors, wedges, and the like. Can be.

Referring to FIG. 1, a heater element 121 may be disposed above the dielectric lead 120 to facilitate internal heating of the process chamber 110. The heater element 121 may be disposed between the dielectric lead 120 and the horizontal induction coils 109 and 111 and the power applying electrodes 102 and 103. In some embodiments, the heater element 121 may include a resistive heating element and a power source 123 such as an AC power source that provides sufficient energy to control the temperature of the heater element 121 to about 50 to about 100 degrees Celsius. Can be connected to. In certain embodiments, the heater element 121 may be an open disconnect heater. In certain embodiments, the heater element 121 may include an uninterrupted heater, such as an annular element, to facilitate uniform plasma formation in the process chamber 110.

 For example, FIG. 4 shows a top view of a heater element 121 according to some embodiments of the invention. The heater element 121 may include an annular portion 300 having a fin 302 extending inwardly. In certain embodiments, annular portion 300 may be disposed along the periphery of dielectric lead 120 as shown in FIGS. 1 and 3. For example, the annular portion 300 may have an outer diameter that is substantially the same as the outer diameter of the dielectric lead 120. In certain embodiments, annular portion 300 may have an outer diameter that is greater than or less than the outer diameter of dielectric lead 120. Other suitable configurations of the annular portion 300 can be used that allow for substantially uniform heating of the dielectric leads 120. Fins 302 may be any suitable width, length, number, and / or location relative to annular portion 300 to provide a desired amount and distribution of heat in process chamber 100. As shown in FIG. 3, the fin 302 may be disposed symmetrically with respect to the annular portion 300 of the heater element 121 and may extend inward radially therefrom.

Referring to FIG. 1, during operation, a substrate 114 (such as a semiconductor wafer or other substrate suitable for plasma processing) may be disposed on the pedestal 116 and the process gas may be in a gaseous state within the process chamber 110. It may be supplied from gas panel 138 through inlet port 126 to form a mixture. As discussed in greater detail in FIG. 5, power is supplied from the plasma power source 118 to the horizontal induction coils 109, 111 and the vertical induction coil 113 so that the gaseous mixture 150 is processed in the process chamber 110. May be ignited into the plasma 155. In some embodiments, power from the bias source 122 may also be provided to the pedestal 116. The pressure in the interior of the process chamber 110 may be controlled using the throttle valve 127 and the vacuum pump 136. The temperature of the conductive body 130 can be controlled using conduits (not shown) formed through the conductive body 130.

The temperature of the wafer 114 may be controlled by stabilizing the temperature of the support pedestal 116. In one embodiment, helium gas from gas source 148 may be provided via gas conduit 149 with a channel formed between the groove (not shown) and the backside of wafer 114 disposed on the pedestal surface. Helium gas is used to facilitate heat transfer between the pedestal 116 and the wafer 114. During processing, support pedestal 116 may be heated to a steady state temperature by a resistive heater (not shown) therein and helium gas may facilitate uniform heating of wafer 114. Using such thermal control, the wafer 114 may be maintained at a temperature of, for example, 0 ° C to 500 ° C.

The controller 140 includes a central processing unit (CPU) 144, a memory 142, and a support circuit 146 for the CPU 144 to facilitate control of the components of the reactor 100 and the plasma formation method. do. Controller 140 may be used in industrial settings to control various chambers and subprocessors. The memory, or computer readable medium, of the CPU 144 may be one or more than one, such as random access memory (RAM), read only memory (ROM), floppy disk, hard disk, or any other form of local or remote digital storage. It may be a readily available memory. The support circuit 146 is coupled to the CPU 144 to support the processor in a conventional manner. Such circuits include cache, power supplies, clock circuits, input / output circuits and subsystems, and the like. The method of the present invention can be stored in the memory 142 as a software routine that can be executed or executed to control the operation of the plasma reactor 100 in the manner described below. The software routine may also be stored and / or executed by a second CPU (not shown) located remotely from hardware controlled by the CPU 144.

5 illustrates a method 400 of forming a plasma in a field enhanced inductively coupled reactor, similar to the plasma reactor 100 described above, in accordance with certain embodiments of the present invention. The method generally begins at "402" where a process gas (or gases) is provided to the process chamber 110. Process gas or gases may be supplied from gas panel 138 via inlet port 126 and form gaseous mixture 150 in chamber 110. Chamber components, such as conductive body 130, dielectric leads 120, and support pedestal 116, may be heated as described above to a desired temperature before or after process gas is provided.

Dielectric lead 120 may be heated by supplying power from power source 123 to heater element 121. The power supplied can be controlled to maintain the process chamber 110 at a desired temperature during process processing.

Next, at 404, RF power from RF power source 118 may be provided to the horizontal induction coil and the vertical induction coil to be inductively capacitively coupled to process gas mixture 150, respectively. While other power and frequencies may be used to form the plasma, RF power may be provided at exemplary frequencies up to 4000 W and adjustable frequencies of 50 kHz to 13.56 MHz.

In certain embodiments, the first positive RF power may be inductively coupled to the process gas via the horizontal induction coil and the vertical induction coil, as shown at 406. The first amount of RF power applied to the horizontal induction coil 109 is caused by the portion of the first amount of RF power that is inductively coupled into the heater element 121 by the non-interruptible heating element (eg, heater element). 121 may be undesirably reduced by the presence of an uninterrupted heating element), which makes it more difficult to undesirably impinge the plasma. However, when the second amount of RF power applied to the horizontal induction coil 111 is not capacitively coupled into the process gas and inductively coupled to the heater element 121, as shown at " 508 " The second amount of RF plasma is improved in performance so as to collide with the plasma under a wider range of conditions.

At 410, the plasma 155 is formed from the process gas mixture 150 using a first amount of RF power and a second amount of RF power provided to the horizontal induction coils 109, 111 and the vertical induction coil, respectively. . When colliding with the plasma to obtain plasma stabilization, the method 400 generally ends and the plasma processing can continue as desired. For example, the process may continue at least partially using RF power settings and other process parameters per standard process regime. Alternatively or in combination, the power applying electrodes 102 and 103 connected to the horizontal moving coils can be moved horizontally or the horizontal moving coils can be varied in distance to change the capacitive coupling of RF power into the process chamber during the process. The vertical moving coil can change the capacitive coupling of RF power into the process chamber 100 by changing its vertical position or changing its spacing.

Thus, a field enhanced inductively coupled plasma reactor and methods of use are provided herein. The field enhanced inductively coupled plasma reactor of the present invention advantageously improves the RF power available to collide with the plasma in the chamber without altering other plasma properties, such as plasma uniformity or ion density. The field enhanced inductively coupled plasma reactor of the present invention may further advantageously control and / or adjust plasma properties such as uniformity and / or density during processing.

While the foregoing is directed to embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

100: plasma reactor 102, 103: power application electrode
104: power divider 109: first horizontal induction coil
110: process chamber 111: second horizontal induction coil
113: vertical induction coil 114: substrate
116: substrate support pedestal 118: plasma power source
120: dielectric lead 121: heater element
122: bias power supply 123: power supply
126: inlet port 127: throttle valve
130: conductive body 134; Electrical grounding
136: vacuum pump 138: gas panel
140: controller 142: memory
144: CPU 146: support circuit
148: gas source 155: plasma
160: plasma source assembly 300: annular portion

Claims (11)

A field enhanced inductively coupled plasma processing apparatus,
A process chamber having a dielectric lead;
A plasma source assembly disposed over said dielectric lead,
A first horizontal induction coil helically positioned at one end on the left with respect to the center and the other end on the right with respect to the center;
A second horizontal induction coil spirally positioned at one end to the right of the center and the other end to the left of the center;
A first power application electrode and a second power application electrode electrically connected to any one of the first horizontal induction coil and the second horizontal induction coil to capacitively couple RF energy into the process chamber;
A first positioning mechanism coupled to the first and second power applying electrodes to change the horizontal position of the power applying electrodes;
A power divider connected to the first power applying electrode and the second power applying electrode to distribute a relative amount of RF power by capacitor coupling; And
And an RF generator coupled to the power divider. The method of claim 1,
And the first position adjustment mechanism changes the horizontal position of the power application electrode. The method of claim 1,
And the first position adjustment mechanism is coupled to the horizontal induction coil to vary the spacing of the horizontal induction coil. delete delete 4. The method according to any one of claims 1 to 3,
And a vertical induction coil connected to the horizontal induction coil and disposed on a side of a dielectric lead. The method according to claim 6,
And a second position adjustment mechanism that moves the vertical position of the vertical induction coil as a whole or changes the spacing of the vertical induction coil. The method of claim 7, wherein
Wherein said first and second positioning mechanisms comprise at least one of a lead screw, a linear bearing, a stepper motor, and a wedge. The method according to any one of claims 1 to 3,
And a heater element disposed between the power applying electrode and the dielectric lead of the plasma source assembly. delete delete

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