Hybrid inductively coupled plasma source for ion and radical etching

Abstract

An apparatus for an inductively coupled plasma (ICP) chamber provides both high power and low power etching capabilities in a single chamber. In some embodiments, the apparatus may comprise a dielectric tube positioned vertically along a central axis of at least one planar coil perpendicular to and surrounding the dielectric tube and has a first end with a first opening with a first diameter and a second end with a second opening with a second diameter smaller than the first opening and is configured to contain inductively coupled plasma, at least one electromagnetic coil surrounding the dielectric tube that is configured to control ions or plasma internally in the dielectric tube, and at least one coil surrounding the dielectric tube above the planar coil where the at least one coil is configured to generate inductively coupled plasma internally in the dielectric tube.

Description

PATENTAttorney Docket No.: 44024990WO1Hybrid Inductively Coupled Plasma Source for Ion and Radical EtchingFIELD

[0001] Embodiments of the present principles generally relate to semiconductor processing of semiconductor substrates.BACKGROUND

[0002] Etching is used in semiconductor manufacturing to form semiconductor structures on substrates. The etching is typically accomplished using ions generated from plasma. Inductively coupled plasma (ICP) semiconductor chambers may produce such ions using high power sources. If sensitive structures have been formed on the substrates, the use of high-power etching may damage the sensitive structures. To avoid damaging the sensitive structures, the substrates are transferred to a second process chamber to undergo low power etching using radicals. The inventors have observed that the transferring of the substrates back and forth between different process chambers substantially impacts the throughput of the substrates and production yields. In addition, care must be taken when transferring the substrate to not expose the substrate to the environment as metals used in the substrate may oxidize and require additional cleaning steps between etching processes, further impacting the substrate throughput.

[0003] Accordingly, the inventors have provided methods and apparatus for performing high power etching using ions and low power etching using radicals in a single process chamber with a hybrid plasma source.SUMMARY

[0004] Methods and apparatus for providing a hybrid plasma source for a etch process chamber are provided herein.

[0005] In some embodiments, an apparatus for an inductively coupled plasma (ICP) chamber may comprise a dielectric tube positioned vertically along a central axis of at least one planar coil perpendicular to and surrounding the dielectric tube where the dielectric tube has a first end with a first opening with a first diameter and a second end with a second opening with a second diameter smaller than the first opening and the dielectric tube is configured to contain11613959_1PATENTAttorney Docket No.: 44024990WO1 inductively coupled plasma, at least one electromagnetic coil surrounding the dielectric tube where the at least one electromagnetic coil is configured to control ions or plasma internally in the dielectric tube, and at least one coil surrounding the dielectric tube above the at least one planar coil where the at least one coil is configured to generate inductively coupled plasma internally in the dielectric tube.

[0006] In some embodiments, the apparatus may further comprise a dielectric tube that has a first gas passage in a wall of the dielectric tube extending from the first end of the dielectric tube to the second end of the dielectric tube, a dielectric tube that has an end cap with an internal gas passage that interfaces with the second end and extends the internal gas passage into a first end of the second opening, an end cap that is a metal material, a second opening that has a nozzle at a second end inside of the dielectric tube, a nozzle that has a plurality of holes, at least one electromagnetic coil that is connected to a DC power source, at least one coil that is connected to an RF power source, a first end of the dielectric tube interfaces with a hub which has a plurality of separated gas passages and a central opening with a diameter approximately equal to the first diameter, a hub that also interfaces with a gas delivery nozzle that projects into a process volume of ICP chamber where the gas delivery nozzle has a central opening with a diameter approximately equal to the first diameter, a gas delivery nozzle that has a plurality of gas passages with one or more outlet angles, a baffle that is positioned between the hub and the gas delivery nozzle and configured to block ions from plasma generated in the dielectric tube, a dielectric tube that has a faraday shield surrounding the dielectric tube and is constructed with a plurality of electrically isolated segments with a plurality of vertical slots in the electrically isolated segments and a faraday shield that is electrically floating or electrically grounded, and / or a ferrite shield that is positioned to block electromagnetic fields generated by the at least one electromagnetic coil surrounding the dielectric tube from the at least one planar coil surrounding the dielectric tube.

[0007] In some embodiments, an apparatus for etching substrates may comprise a process chamber with a process volume positioned above a21613959_1PATENTAttorney Docket No.: 44024990WO1 substrate support and configured to etch substrates, one or more RF power sources configured to power one or more inductively coupled plasmas, a primary coil set electrically connected to the one or more RF power sources and configured to provide inductively coupled plasma internal to a process volume of the process chamber to provide high power plasma etching for substrates where the primary coil set has one or more planar coils surrounding a central axis of a process chamber, a secondary coil set electrically connected to the one or more RF power sources and configured to provide inductively coupled plasma inside a dielectric tube to provide low power plasma etching for substrates where the secondary coil set has one or more coils surrounding the dielectric tube that is positioned vertically along the central axis and perpendicular to the primary coil set, at least one electromagnetic coil surrounding the dielectric tube where the at least one electromagnetic coil is configured to control ions or plasma internally in the dielectric tube, and a controller that interfaces with the primary coil and secondary coil to control plasma generation in the process volume and plasma generation in the dielectric tube.

[0008] In some embodiments, the apparatus may further comprise high-power plasma etching that uses approximately 3kW or higher of RF power from the one or more RF power sources and low power plasma etching that uses less than approximately 1 kW of RF power from the one or more RF power sources, a primary coil set and a secondary coil set that are energized separately or together by the controller, a ferrite shield that is positioned to block electromagnetic fields generated by the at least one electromagnetic coil surrounding the dielectric tube from the primary coil set, and / or a dielectric tube that has a first end with a first opening with a first diameter and a second end with a second opening with a second diameter that is smaller than the first opening where the dielectric tube has a first gas passage in a wall of the dielectric tube extending from the first end of the dielectric tube to the second end of the dielectric tube, the dielectric tube has an end cap with an internal gas passage that interfaces with the second end and extends the internal gas passage into a first end of the second opening, and the second opening has a nozzle at a second end inside of the dielectric tube.31613959_1PATENTAttorney Docket No.: 44024990WO1

[0009] In some embodiments, a method of etching a substrate in a single process chamber may comprise generating a high power inductively coupled plasma in a process volume of a process chamber using a planar coil set positioned about a central axis of the process chamber and above the process volume when commanded by a controller of the single process chamber where the high power inductively coupled plasma uses approximately 5kW or higher of RF power, etching the substrate with ions generated with the high power inductively coupled plasma, generating a low power inductively coupled plasma in a dielectric tube positioned vertically along the central axis and perpendicular to the planar coil set using a vertical coil set surrounding the dielectric tube when commanded by the controller of the single process chamber where the low power inductively coupled plasma uses approximately 500W or lower of RF power, and etching the substrate with radicals generated with the low power inductively coupled plasma.

[0010] Other and further embodiments are disclosed below.BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Embodiments of the present principles, briefly summarized above and discussed in greater detail below, can be understood by reference to the illustrative embodiments of the principles depicted in the appended drawings. However, the appended drawings illustrate only typical embodiments of the principles and are thus not to be considered limiting of scope, for the principles may admit to other equally effective embodiments.

[0012] Figure 1 depicts a cross-sectional view of a process chamber with a hybrid ICR source in accordance with some embodiments of the present principles.

[0013] Figure 2 depicts a cross-sectional view of a dielectric tube with a secondary coil set surrounded by an electromagnet in accordance with some embodiments of the present principles.

[0014] Figure 3 depicts a cross-sectional view of a dielectric tube and a ferrite shield in proximity of a primary coil set in accordance with some embodiments of the present principles.41613959_1PATENTAttorney Docket No.: 44024990WO1

[0015] Figure 4 depicts a cross-sectional view of a gas flow within a dielectric tube in accordance with some embodiments of the present principles.

[0016] Figure 5 depicts a cross-sectional view of a dielectric tube in accordance with some embodiments of the present principles.

[0017] Figure 6 depicts a cross-sectional view of a dielectric tube and end cap in accordance with some embodiments of the present principles.

[0018] Figure 7 depicts an isometric view and a top-down cross-sectional view of a dielectric tube with a faraday shield in accordance with some embodiments of the present principles.

[0019] Figure 8 depicts an isometric view of a power distribution hub, conductors, and an inner primary coil set in accordance with some embodiments of the present principles.

[0020] Figure 9 depicts an isometric view of a secondary coil set and an electromagnet in accordance with some embodiments of the present principles.

[0021] Figure 10 depicts a top-down sectional view of a gas delivery hub in accordance with some embodiments of the present principles.

[0022] Figure 11 depicts a cross-sectional view of a central gas delivery nozzle with one or more gas passages in accordance with some embodiments of the present principles.

[0023] Figure 12 depicts a top-down sectional view of a central gas delivery nozzle with one or more gas passages in accordance with some embodiments of the present principles.

[0024] Figure 13 is a method of etching a substrate with a low-power etching process and a high-power etching process in a single process chamber in accordance with some embodiments of the present principles.

[0025] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. The figures are not drawn to scale and may be simplified for clarity. Elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.51613959_1PATENTAttorney Docket No.: 44024990WO1DETAILED DESCRIPTION

[0026] The methods and apparatus provide an etch process chamber with both low power radical etching and high-power ion etching capabilities using a hybrid plasma source. The hybrid plasma source can be used to etch substrates with ions and / or radicals in a single process chamber without the need to transfer the substrates between low power etch chambers and high power etch chambers.

[0027] Traditionally, high power etching (greater than 5kW) is performed in a first etch chamber and low power etching (less than 1 kW) is performed in a second etch chamber. The low power etching is used when parts of the device cannot withstand the higher power of the ion etching. Because two different semiconductor process chambers are needed to perform both high and low power etching, the wafer containing the device structure must be transported back and forth between the two etching chambers. The transporting between chambers slows down the semiconductor processing which in turn reduces the overall number of device structures which can be constructed for a given amount of time. In addition, the semiconductor manufacturer needs to invest in and maintain two different types of etching chambers (low and high-power etching chambers) which increases the cost of the manufacturing process. The present principles provide a semiconductor chamber with both a low power etching capability and a high-power etching capability by adding a remote plasma source (dielectric tube and secondary coils) within a high-power etching chamber. The semiconductor chamber becomes a ‘hybrid’ as the chamber has a low power plasma RF source for radical generation and a high-power plasma RF source for ion generation.

[0028] A first set of coils is used to form inductively coupled plasma into the chamber to etch using ions formed in the plasma inside of the process volume of the chamber. A remote plasma source formed by a dielectric tube which is positioned centrally to the first set of coils and above the process volume of the chamber is used to etch using radicals. The dielectric tube includes a second set of coils wrapped around the tube to form inductively coupled plasma within the dielectric tube. The plasma formed within the dielectric tube produces radicals which are then flowed into the semiconductor chamber to etch the substrate in a61613959_1PATENTAttorney Docket No.: 44024990WO1 low power mode. The chamber of the present principles operates as both a high- power etching chamber (ion etching) and also as a low power etching chamber (radical etching).

[0029] The independent ion and radical etching capabilities can be used together to control plasma behavior above the wafer in the process volume of the process chamber by using a remote source for electronegative gases like sulfur hexafluoride (SFe) and the like to ignite the plasma for primary coil high- power etching. In some cases, the dielectric tube with the secondary coil can be energized to start the spark / ignite gas of the primary high-power etching plasma in the process volume with inert or equivalent gases inside the dielectric tube and which aids in the primary ion (high power) etch with the traditional primary coil setup. The advantages of the present principles include expanded capability with both traditional pairs of RF coils for ion etching and independently powered remote RF coils at the center around the dielectric tube for radical etching. In some embodiments, an electromagnetic core is introduced around the dielectric tube for improved plasma and / or ion control and can be used as a tuning knob during low-power etching processes. With the present principles, arcing and electromagnetic interference that occurs when using metal gas lines is eliminated, as the gas delivery path for radical generation is formed in the dielectric of a sidewall of the dielectric tube. The present techniques have the ability to retain both center gas delivery for traditional high-power RF source etching while using the same interface with an ion blocking baffle for delivering radicals from the low-power RF plasma source.

[0030] The present principles provide a low-power RF source that provides, at least, a remote high-density source that operates in a radical only mode and / or with ions for plasma ignition, a remote source with easy ignitions, a source that operates along with and independently of a high-power RF source, and / or capabilities to limit high-power RF power delivery from affecting the low-power RF plasma formed in the dielectric tube. In some embodiments, a ferrite shield is used to limit interaction of the primary high-power RF coils. The ferrite shield is selected to have low permeability variability, to have thermal management capability for variability control (e.g., low degradation at less than approximately 200 degrees Celsius but with high performance), and / or to have a remote plasma71613959_1PATENTAttorney Docket No.: 44024990WO1 generation area that has a line of sight for ion flux mode directly into the process volume of the chamber. In some embodiments, the high-power RF primary coil may be completely planar or with vertical sections on the outer side of coil. In some embodiments, the inner and outer coils may have different numbers of turns (e.g., three turns on the inner coil and 2-3 turns on the outer coil to balance power, etc.). The chamber of the present principles includes, in some embodiments, space for the remote plasma source which also enables balanced power deposition, increased high voltage on the inner primary coil near the lid for improved source only ignition, a ferrite shield above the inner primary coil and on the inner side of the inner primary coil to limit primary high-power RF deliver into the remote cavity of the dielectric tube, and / or increased power coupling (decreased current) with approximately 5% increase or less in parasitic loss.

[0031] Fig. 1 is a process chamber 100 with a hybrid I CP source for low-power etching and high-power etching. In some embodiments, the process chamber 100 may be used for front end of line (FEOL) etch processes. The chamber body 102 includes a substrate support 104 to hold a substrate 106 during processing. The substrate support 104 may also include an electrode 108 electrically connected to a bias power source 110 via a bias match network 112. A process shield 120 surrounds a process volume 116 in which a first plasma 118 is generated to produce ions for high-power etching processes. Gases used in the generation of ions from the first plasma 118 may be supplied by a first gas supply 126 to the center of the process volume 116 and / or around the perimeter of the process volume 116 through side nozzles 186. Vacuum levels within the process volume 1 16 may be adjusted using a vacuum pump 114 connected to the chamber body 102. The ICP source assembly 130 includes an inner primary coil set 146 and an outer primary coil set 148. In some embodiments, the inner primary coil set 146 and the outer primary coil set 148 may be planar and lie in the same plane as depicted in Fig. 1. The ICP source assembly 130 includes a first power source assembly 154 with a high-power RF source 156 connected to a high-power distribution hub 152 via a high-power RF match network 158. In some embodiments, the high-power RF source 156 may provide approximately 3kW or higher of RF power for performing ion etching in the process volume 116 of the process chamber 100. In some embodiments, the high-power RF source81613959_1PATENTAttorney Docket No.: 44024990WO1156 may provide approximately 5kW or higher RF power for performing ion etching in the process volume 116 of the process chamber 100. The high-power distribution hub 152 provides symmetrically distributed power via a symmetrical conductor set 150 to the inner primary coil set 146 and the outer primary coil set 148 for ICP plasma generation within the process volume 116. The lid 128 of the process chamber 100 is a dielectric window for primary ICP plasma generation within the process volume 116.

[0032] The process chamber 100 is a multiple RF power source chamber and includes a second power source assembly 160 with a low-power RF source 162 connected to a secondary coil set 144 via a low-power RF match network 164. The low-power RF source 162 provides power to the secondary coil set 144 to generate ICP plasma within the dielectric tube 184 to generate radicals for low- power etching within the process volume 116. The dielectric tube 184 is positioned vertically along a central axis 198 of an inner primary coil set 146 and / or an outer primary coil set 148 which surround the dielectric tube 184. The dielectric tube 184 contains a second plasma 172 which is inductively coupled to a secondary coil set 144 and is used to form radicals for low-power etching processes in the process volume 116 of the process chamber 100. In some embodiments, the low-power RF source 162 may provide approximately 1 kW or less of RF power to the secondary coil set 144 for performing radical etching in the process volume 116 of the process chamber 100. In some embodiments, the low-power RF source 162 may provide approximately 500W or less of RF power to the secondary coil set 144 for performing radical etching in the process volume 116 of the process chamber 100.

[0033] The second plasma 172 is formed when the secondary coil set 144 is energized. Gases for radical formation flow from a second gas source 122 into a gas distribution hub 174 through a dielectric tube gas passage 176 in a wall of the dielectric tube 184, through an end cap gas passage 180 in the end cap 166, through a nozzle 168 inserted into a first opening 514 at a first end 510 (see Fig. 5) of the dielectric tube 184, and into a radical and / or ion source generation region 170 of the dielectric tube 184. The second plasma 172 and / or ions are controlled by an electromagnet 140 which draws power from a DC power source91613959_1PATENTAttorney Docket No.: 44024990WO1138. In some embodiments, the electromagnet 140 may be positioned below the secondary coil set 144 (depicted in Fig. 1) and / or positioned around the perimeter of the secondary coil set 144 (depicted in Fig. 2). The Lorentz force provided by the electromagnet 140 can be used to toggle from a radical only flow into the process volume 116 of the process chamber 100 to a radical and ion flow into the process volume 116 of the process chamber 100.

[0034] A second opening of a second end of the dielectric tube 184 interfaces with a center opening in the gas distribution hub 174 which interfaces with a center opening of a gas delivery nozzle 132 with one or more gas passages 134. In some embodiments, the dielectric tube 184 may have a side opening 188 or nozzle connected to a second dielectric tube gas passage 178. The side opening 188 may be supplied by an optional third gas source 124 via the second dielectric tube gas passage 178. The flow of the gas from the side opening 188 may assist in optimizing the containment of the second plasma 172, the blocking of ions from the second plasma, assisting in the flow of radicals into the process volume 116 of the process chamber 100, and / or energizing of the radicals formed by the second plasma 172 prior to entering the process volume 116, and the like. The side opening 188 may have an angled nozzle to direct flow downwards, perpendicular to the sidewalls inside the dielectric tube 184, and / or upwards inside of the dielectric tube 184 and the like. In some embodiments, an ion baffle 136 may be used to further block ions from entering into the process volume 116 of the process chamber 100. In some embodiments, the ion baffle 136 may be formed of ceramic material with a plurality of holes that permit radicals to flow through while blocking ions from entering the process volume 116. In some embodiments, the ion baffle136 may be conductive to further aid in blocking ions by applying an opposite electric charge to attract ions and, thus, block ions from entering the process volume 116.

[0035] In some embodiments, due to the close proximity of the inner primary coil set 146, a ferrite shield 142 may be installed in the process chamber 100 to minimize the impact of the electromagnetic fields produced by the inner primary coil set 146 on the second plasma generated in the dielectric tube 184. The shape and positioning of the ferrite shield 142 may be altered (e.g., see Fig. 3,101613959_1PATENTAttorney Docket No.: 44024990WO1 ferrite shield 302) based on the positioning of the inner primary coil set 146 and the positioning of the secondary coil set 144 and / or the location of the second plasma 172. In some embodiments, a faraday shield 182 surrounds the dielectric tube 184. The faraday shield 182 may have slots (e.g., see Fig. 7, slots 702) to facilitate in controlling the plasma formation within the dielectric tube 184 by the secondary coil set 144.

[0036] In some embodiments, a controller 190 controls the operation of any apparatus, systems, assemblies, parts, or methods described herein, including the process chamber 100. The controller 190 may use a direct control of the process chamber 100, or alternatively, a control of the computers (or other controllers) associated with the process chamber 100. The controller 190 may also control the primary coils and / or secondary coils to control plasma generation in the process volume and / or plasma generation in the dielectric tube. In operation, the controller 190 enables data collection and feedback from the process chamber 100 to optimize performance of the process chamber 100 and to control the processes according to methods described herein such as low- power and high-power etching processes within a single chamber. The controller 190 generally includes a central processing unit (CPU) 192, a memory 194, and a support circuit 196. The CPU 192 may be any form of a general-purpose computer processor that can be used in an industrial setting. The support circuit 196 is conventionally coupled to the CPU 192 and may comprise a cache, clock circuits, input / output subsystems, power supplies, and the like. Software routines, such as methods as described herein may be stored in the memory 194 and, when executed by the CPU 192, transform the CPU 192 into a specific purpose computer (controller 190). The software routines may also be stored and / or executed by a second controller (not shown) that is located remotely from the process chamber 100.

[0037] The memory 194 is in the form of computer-readable storage media that contains instructions, when executed by the CPU 192, to facilitate the operation of the semiconductor processes and equipment. The instructions in the memory 194 are in the form of a program product such as a program that implements methods of the present principles. The program code may conform to any one of111613959_1PATENTAttorney Docket No.: 44024990WO1 a number of different programming languages. In one example, the disclosure may be implemented as a program product stored on a computer-readable storage media for use with a computer system. The program(s) of the program product define functions of the aspects (including the methods and processes described herein). Illustrative computer-readable storage media include, but are not limited to: non-writable storage media (e.g., read-only memory devices within a computer such as CD-ROM disks readable by a CD-ROM drive, flash memory, ROM chips, or any type of solid-state non-volatile semiconductor memory) on which information is permanently stored; and writable storage media (e.g., floppy disks within a diskette drive or hard-disk drive or any type of solid-state random access semiconductor memory) on which alterable information is stored. Such computer-readable storage media, when carrying computer-readable instructions that direct the functions of the methods described herein, are aspects of the present principles.

[0038] In some embodiments, an electromagnet 240 surrounds the secondary coil set 144 as depicted in a view 200 of Fig. 2. Positioning of the electromagnet 240 around the secondary coil set 144 makes the electromagnet 240 less susceptible to interaction with the inner primary coil set 146, and the ferrite shield 142 may not be needed in some cases. In some embodiments, the ferrite shield 302 may surround and cover a bottom of the secondary coil set 144 as depicted in a view 300 of Fig. 3. The ferrite shield 302 blocks the interaction of the inner primary coil set 146 and / or the electromagnet 140 with the secondary coil set 144. The ferrite shield 302 may be used in place of the ferrite shield 142 or used in conjunction with the ferrite shield 142. Gases used for generating plasma within the dielectric tube 184 come from a gas supply source (e.g., second gas source 122 of Fig. 1 , etc.) and through gas supply tubes into the gas delivery hub 174 as indicated by gas flow 402 as depicted in a view 400 of Fig. 4. The gas flow 402 is then directed through the dielectric tube gas passage 176 inside of the sidewall of the dielectric tube 184 and into an end cap gas passage 180 of the end cap 166. The dielectric tube gas passage 176 is nonconductive and allows for gas flow without using a metal gas tube which would interfere with the secondary coil set 144 when generating plasma in the dielectric tube 184.121613959_1PATENTAttorney Docket No.: 44024990WO1

[0039] In some embodiments, the end cap 166 may be attached to the dielectric tube 184 by fasteners 404. The end cap 166 may be formed of a conductive material such as aluminum and the like. The gas flow 402 continues down into the nozzle 168 inserted into a first opening 514 at a first end 510 (see Fig. 5) of the dielectric tube 184, and into the radical and / or ion source generation region 170 of the dielectric tube 184. The nozzle 168 may have more than one gas outlet 406 which may be angled in any direction to facilitate in dissipating the gas or gases into the second plasma 172 with the dielectric tube 184. The second plasma 172 generates radicals and ions from the gases which flow downward towards the process volume 116 of the process chamber 100. The electromagnet 140 may be energized to produce electromagnetic fields 416 that influence the trajectories of the ions to facilitate in reducing the number of ions that flow into the process volume 116. The electromagnet 140 may also facilitate to increase the density of the second plasma 172 by confining the second plasma with the electromagnetic fields 416. In some cases, some ions may escape and continue to flow downward and may be blocked by the ion baffle 136 which aids in further reducing the number of ions that flow into the process volume 116. Radicals produced by the second plasma 172 are largely unaffected by the electromagnet 140 or the ion baffle 136 and continue to flow 412 into the process volume 116 for low-power etching of the substrate 106.

[0040] In some embodiments, the side opening 188 or nozzle may flow gas in any direction inside of the dielectric tube 184. The side opening 188 may be supplied by an optional third gas source 124. The gas flow 410 from the side opening 188 may assist in optimizing the containment of the second plasma 172, the blocking of ions from flowing from the second plasma 172 to the process volume 116, assisting in the flow 412 of radicals into the process volume 116 of the process chamber 100, and / or energizing the radicals prior to entry into the process volume 116, and the like. The side opening 188 may have an angled nozzle to direct flow downwards, perpendicular to the sidewalls inside the dielectric tube 184, and / or upwards inside of the dielectric tube 184 and the like. In some embodiments, an ion baffle 136 may be used to further block ions 414 from entering into the process volume 116 of the process chamber 100. The ion baffle 136 may be grounded or may have a floating or set voltage. The gas flow131613959_1PATENTAttorney Docket No.: 44024990WO1408 from the optional third gas source 124 may be, in some embodiments, an inert gas and the like.

[0041] In some embodiments, the dielectric tube 184 has a height 502 that is greater than a width 504 as depicted in a view 500 of Fig. 5. The first end 510 has a first opening 514 with a first diameter 508. The second end 512 has a second opening 516 with a second diameter 506 that is greater than the first diameter 508. The second opening 516 extends substantially through the height 502 of the dielectric tube 184 to form the radical and / or ion source generation region 170 in which the second plasma 172 is formed from which the radicals used in low-power etching are sourced. The dielectric tube gas passage 176 is formed into the sidewall 518 of the dielectric tube 184. In some embodiments, the dielectric tube gas passage 176 may be formed by drilling at least 50% or more of the way through the height 502 of the dielectric tube 184, flipping the dielectric tube 184 and drilling through the rest of the height of the dielectric tube 184. When drilling from the top and then from the bottom of the dielectric tube 184, one or more of the drilled portions of the dielectric tube gas passage 176 may be angled 532 less than 90 degrees from a plane 530 in which the second end 512 of the dielectric tube 184 lies. In some embodiments, the dielectric tube 184 may be formed of a ceramic material such as, for example but not limited to, aluminum oxide and the like.

[0042] In some embodiments, a plurality of recesses 602 may be formed into sides of the dielectric tube 184 nearer the first end 510 as depicted in a view 600 of Fig. 6. The recesses 602 are formed to accept a block 604 of material in which one or more of the fasteners 404 may penetrate into in order to attach the end cap 166 to the dielectric tube 184. The block 604 may be formed of a material with a high temperature tolerance such as, but not limited to, polyether ether ketone (PEEK) and the like. The dielectric tube 184 interfaces at the second end 512 with the gas distribution hub 174. In some embodiments, the faraday shield 182 attached to the dielectric tube 184 may be formed of a first half 182A and a second half 182B that are separated from each other as depicted in a view 700A of Fig. 7. In some embodiments, the faraday shield 182 has a plurality of slots 702 that have a height 706 greater than a width 704. The number of slots 702,141613959_1PATENTAttorney Docket No.: 44024990WO1 the width 704, and / or the height 706 may be adjusted to allow for adjustability of the effects of the secondary coil set 144 on the second plasma 172. Larger slots provide more energy to be inductively coupled into the second plasma 172 which increases plasma density and radical density while smaller slots reduce the amount of energy inductively coupled into the second plasma 172 which decreases plasma density and radical density.

[0043] The slots 702 also aid in cooling of the dielectric tube 184. The generation of the second plasma 172 inside of the dielectric tube 184 generates a substantial amount of heat. The slots 702 allow, for example but not limited to, direct flow of air on the dielectric tube 184 to cool the dielectric tube 184 during use. In some embodiments, the faraday shield 182 may be grounded or left floating. A grounded faraday shield allows for higher power (greater than 500W) to be inductively coupled into the second plasma 172. A floating faraday shield allows for more tunability (higher control of radicals). When the secondary coil set 144 is energized, a chance exists that plasma may be formed inside of the dielectric tube gas passage 176 in the sidewall 518 of the dielectric tube 184. In some embodiments as depicted in a top-down cross-section view 700B, the slots 702 are positioned such that the faraday shield 182 covers or shields the dielectric tube gas passage 176 from the fields of the secondary coil set 144 to reduce the direct energy transfer from the secondary coil set 144 into the dielectric tube gas passage 176 to prevent plasma formation inside of the dielectric tube gas passage 176.

[0044] A view 800 of Fig. 8 depicts an example of a symmetrical conductor set 150 with four conductors 802-808 that connect the inner primary coil set 146 to the high-power distribution hub 152. The symmetrical conductor set 150 may also include more than four conductors or less than four conductors. The symmetrical conductor set 150 is formed such that the conductors form around the dielectric tube 184 without interfering with the electromagnet 140 and / or the secondary coil set 144. Current from the high-power RF source 156 flows 812 from the high-power distribution hub 152 down through the conductors and into the inner primary coil set 146. RF current then travels to RF ground through the ends 810 of the inner primary coil set 146. The space provided within the151613959_1PATENTAttorney Docket No.: 44024990WO1 symmetrical conductor set 150 provides room for the dielectric tube 184 and for a secondary ICP plasma generation assembly 908 (depicted in a view 900 of Fig. 9). In some embodiments, the secondary ICP plasma generation assembly 908 may include a supporting structure 906 that interfaces with the secondary coil set 144 to properly position the secondary coil set 144 around the dielectric tube 184 (not shown in Fig. 9) along with support for the electromagnet 140 beneath the secondary coil set 144. In some embodiments, the secondary coil set 144 has power applied at input 902 and is grounded at output 904. As discussed above, in some embodiments, the electromagnet 204 may surround the secondary coil set 144 and, thus, the secondary ICP plasma generation assembly 908 may be reconfigured to hold the electromagnet 204 around and adjacent to the secondary coil set 144 (not shown).

[0045] A top-down sectional view 1000 of Fig. 10 depicts an example of the gas distribution hub 174 that attaches beneath the dielectric tube 184 to the second end 512 of the dielectric tube 184. The gas distribution hub 174 has a central opening 1014 with a diameter 1020 that is equal to or larger than the second diameter 506 of the second opening 516 of the dielectric tube 184 to allow for ion and / or radical flow into the process volume 116 for low-power etching of the substrate 106. In some embodiments, a first gas flow 1002 from the second gas source 122 enters a first gas passage 1022 which connects to a first vertical gas passage 1016. The first vertical gas passage 1016 interacts with the dielectric tube gas passage 176 at the second end 512 of the dielectric tube 184. In some embodiments, a second gas flow 1004 from the optional third gas source 124 enters a second gas passage 1024 which connects to a second vertical gas passage 1018. The second vertical gas passage 1018 may interact with the second dielectric tube gas passage 178 at the second end 512 of the dielectric tube 184.

[0046] In some embodiments, a third gas flow 1006 from the first gas supply 126 enters a third gas passage 1026 which may split into two or more sub-gas passages that connect with a first ring-like gas distribution plenum 1010 within the gas distribution hub 174. The first ring-like gas distribution plenum 1010 distributes gas to one or more gas passages 134 in the gas delivery nozzle 132161613959_1PATENTAttorney Docket No.: 44024990WO1(e.g., see Figs. 11 and 12). The distributed gases are used in the first plasma 118 generated by ICP in the process volume 116 of the process chamber 100 for high-power etching processes. In some embodiments, a fourth gas flow 1008 from the first gas supply 126 or another gas supply different from the first gas supply 126 enters a fourth gas passage 1028 which may split into two or more sub-gas passages that connect with a second ring-like gas distribution plenum 1012 within the gas distribution hub 174. The second ring-like gas distribution plenum 1012 distributes gas to one or more gas passages 134 in the gas delivery nozzle 132 (e.g., see Figs. 11 and 12). The distributed gases are used in the first plasma 118 generated by ICP in the process volume 116 of the process chamber 100 for high-power etching processes. In some embodiments, the gas distribution hub 174 may have more or less than four gas passages and / or more or less than two ring-like gas distribution plenums internal to the gas distribution hub 174.

[0047] A cross-sectional view 1100 of Fig. 11 depicts an example of the gas delivery nozzle 132 with a first end 1124 that attaches beneath the gas distribution hub 174. The gas delivery nozzle 132 has a central opening 1106 with a diameter 1122 that is equal to or larger than the diameter 1020 of the gas distribution hub 174 to allow for ion and / or radical flow into the process volume 116 for low-power etching of the substrate 106. In some embodiments, the central opening 1106 may have an angled flare at a second end 1 126 of the gas delivery nozzle 132 that increases the diameter 1122 of the central opening 1106. The angle 1120 of the flare 1130 may be from approximately zero to approximately 90 degrees relative to a plane 1128 of the second end 1126 of the gas delivery nozzle 132. The flare 1130 may have one or more first angled nozzles 1110 a gas flow 1112 from one or more first gas passages 1108 inward to distribute radicals (or ions) uniformly across the entire surface of the substrate 106. The gas flow 1112 facilitates in neutralization and radial control of the gas distribution and is effective at high pressures, such as but not limited to, approximately 100 mTorr or greater. In some embodiments, the gas is an inert gas. In some embodiments, the gas delivery nozzle 132 may have one or more second gas passages 1104 that flow gases 1118 perpendicular to the substrate 106 in the process volume 116 for high-power etching processes. In some171613959_1PATENTAttorney Docket No.: 44024990WO1 embodiments, the gas delivery nozzle 132 may have one or more third gas passages 1102 that flow gases 1114 at an outward angle 1116 in the process volume 116. In some embodiments, the outward angle 1116 may be from approximately zero to approximately 90 degrees relative to a plane 1128 of the second end 1126 of the gas delivery nozzle 132.

[0048] In some embodiments, the flare 1130 of the gas delivery nozzle 132 may have the gas flow 1112 at a downward angle (angle 1120) and also at a sideways angle 1208 as depicted in a top-down view 1200 of Fig. 12 to facilitate in evenly distributing the gases without the individual gas flows interfering with other individual gas flows within the process volume 116. The sideways angle 1208 may be from greater than zero to approximately 90 degrees relative to the inner wall 1132 of the flare 1130 of the central opening 1106 of the gas delivery nozzle 132. In some embodiments, the one or more first gas passages 1108 may be fed by a first ring-like gas plenum 1206 of the gas distribution hub 174. In some embodiments, the one or more gas passages 1110 may be fed by a second ringlike gas plenum 1204 of the gas distribution hub 174. In some embodiments, the one or more gas passages 1110 may be fed by a third ring-like gas plenum 1202 of the gas distribution hub 174. The diameters and / or distribution of the gas passages in the gas delivery nozzle 132 may be different from the top-down view 1200 of Fig. 12. In addition, the supplying of the gases into the gas passages may be accomplished via a plenum feeding more than one gas passage or fed with gas individually.

[0049] Fig. 13 is a method 1300 of using a hybrid ICP source chamber to perform both low-power etching processes and high-power etching processes in a single chamber. The techniques can be used to operate an etch chamber to achieve both Ion etching (high-power etching) with a primary set of coils and a dielectric tube with a secondary set of coils at a center of dielectric window above the process volume of the etch chamber for radical etching with low power for expanded process capability within same chamber. Existing ICP plasma sources for ion etching typically have a top lid as a dielectric window and inner and outer RF primary coils above the top lid coupled to a high-power RF power source and a gas feed at a center of the process volume for generating plasma inside the181613959_1PATENTAttorney Docket No.: 44024990WO1 process volume of the process chamber for high power application for ion etching. For advance nodes with lower power applications, the nodes need a radical etch additional knob in-situ approach to generate radicals and independently power an additional secondary RF coil a dielectric tube on center for plasma uniformity control and as an additional knob for tuning. The present techniques provide the ability for a plasma chamber with hybrid ICP source architecture to have an expanded capability with a top dielectric window lid for ion etching and a center dielectric tube with embedded holes for gas delivery with an electromagnet core. The present techniques enable both ion and radical etching inside the process volume of the same process chamber independently or, in some embodiments, simultaneously (as a tuning knob to control plasma behavior above a wafer using dielectric tube plasma source for an electronegative gas, such as but not limited to, SFe to assist in igniting plasma in the process volume for primary ion etching.

[0050] In block 1302, one or more substrates are obtained for low-power or high-power etch processing and positioned in the hybrid ICP source chamber. In block 1304, a low power etch process is performed on a first selection of substrates in the hybrid ICP source chamber. Low power applications with less than 3nm nodes need radical etching (low power etching) with extreme uniformity and hardware symmetry to achieve desired process results. The present techniques provide such uniformity and symmetry. An electromagnet surrounding the dielectric tube provide Lorentz forces on the interior of the dielectric tube for improved second plasma control and can be used as a tuning knob. In block 1306, a high-power etch process is performed on a second selection of substrates in the hybrid ICP source chamber. In some embodiments, substrates of the first selection may also be in the second selection and vice versa. The present techniques allow a process chamber to retain both a center gas delivery from a central opening for traditional ICP source high power etching while also using the same central opening with a baffle to deliver radicals for ICP source low power etching (dielectric tube).

[0051] Embodiments in accordance with the present principles may be implemented in hardware, firmware, software, or any combination thereof.191613959_1PATENTAttorney Docket No.: 44024990WO1Embodiments may also be implemented as instructions stored using one or more computer readable media, which may be read and executed by one or more processors. A computer readable medium may include any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computing platform or a “virtual machine” running on one or more computing platforms). For example, a computer readable medium may include any suitable form of volatile or non-volatile memory. In some embodiments, the computer readable media may include a non-transitory computer readable medium.

[0052] While the foregoing is directed to embodiments of the present principles, other and further embodiments of the principles may be devised without departing from the basic scope thereof.201613959_1

Claims

PATENTAttorney Docket No.: 44024990WO1CLAIMS1. An apparatus for an inductively coupled plasma (ICP) chamber, comprising: a dielectric tube positioned vertically along a central axis of at least one planar coil perpendicular to and surrounding the dielectric tube, wherein the dielectric tube has a first end with a first opening having a first diameter and a second end with a second opening having a second diameter smaller than the first opening and wherein the dielectric tube is configured to contain inductively coupled plasma; at least one electromagnetic coil surrounding the dielectric tube, wherein the at least one electromagnetic coil is configured to control ions or plasma internally in the dielectric tube; and at least one coil surrounding the dielectric tube above the at least one planar coil, wherein the at least one coil is configured to generate inductively coupled plasma internally in the dielectric tube.

2. The apparatus of claim 1 , wherein the dielectric tube has a first gas passage in a wall of the dielectric tube extending from the first end of the dielectric tube to the second end of the dielectric tube.

3. The apparatus of claim 2, wherein the dielectric tube has an end cap with an internal gas passage that interfaces with the second end and extends the internal gas passage into a first end of the second opening.

4. The apparatus of claim 3, wherein the end cap is a metal material.

5. The apparatus of claim 3, wherein the second opening has a nozzle at a second end inside of the dielectric tube.

6. The apparatus of claim 5, wherein the nozzle has a plurality of holes.

7. The apparatus of claim 1 , wherein the at least one electromagnetic coil is connected to a DC power source.211613959_1PATENTAttorney Docket No.: 44024990WO18. The apparatus of claim 1 , wherein the at least one coil is connected to an RF power source.

9. The apparatus of claim 1 , wherein the first end of the dielectric tube interfaces with a hub which has a plurality of separated gas passages and a central opening with a diameter approximately equal to the first diameter.

10. The apparatus of claim 9, wherein the hub also interfaces with a gas delivery nozzle that projects into a process volume of ICP chamber, wherein the gas delivery nozzle has a central opening with a diameter approximately equal to the first diameter.11 . The apparatus of claim 10, wherein the gas delivery nozzle has a plurality of gas passages with one or more outlet angles.

12. The apparatus of claim 11 , wherein a baffle is positioned between the hub and the gas delivery nozzle and configured to block ions from plasma generated in the dielectric tube.

13. The apparatus of claim 1 , wherein the dielectric tube has a faraday shield surrounding the dielectric tube and constructed with a plurality of electrically isolated segments with a plurality of vertical slots in the electrically isolated segments and wherein the faraday shield is electrically floating or electrically grounded.

14. The apparatus of claim 1 , wherein a ferrite shield is positioned to block electromagnetic fields generated by the at least one electromagnetic coil surrounding the dielectric tube from the at least one planar coil surrounding the dielectric tube.221613959_1PATENTAttorney Docket No.: 44024990WO115. An apparatus for etching substrates, comprising: a process chamber with a process volume positioned above a substrate support and configured to etch substrates; one or more RF power sources configured to power one or more inductively coupled plasmas; a primary coil set electrically connected to the one or more RF power sources and configured to provide inductively coupled plasma internal to a process volume of the process chamber to provide high power plasma etching for substrates, wherein the primary coil set has one or more planar coils surrounding a central axis of a process chamber; a secondary coil set electrically connected to the one or more RF power sources and configured to provide inductively coupled plasma inside a dielectric tube to provide low power plasma etching for substrates, wherein the secondary coil set has one or more coils surrounding the dielectric tube that is positioned vertically along the central axis and perpendicular to the primary coil set; at least one electromagnetic coil surrounding the dielectric tube, wherein the at least one electromagnetic coil is configured to control ions or plasma internally in the dielectric tube; and a controller that interfaces with the primary coil and secondary coil to control plasma generation in the process volume and plasma generation in the dielectric tube.

16. The apparatus of claim 15, wherein high-power plasma etching uses approximately 3kW or higher of RF power from the one or more RF power sources and low power plasma etching uses less than approximately 1 kW of RF power from the one or more RF power sources.

17. The apparatus of claim 15, wherein the primary coil set and the secondary coil set are energized separately or together by the controller.

18. The apparatus of claim 15, wherein a ferrite shield is positioned to block electromagnetic fields generated by the at least one electromagnetic coil surrounding the dielectric tube from the primary coil set.231613959_1PATENTAttorney Docket No.: 44024990WO119. The apparatus of claim 15, wherein the dielectric tube has a first end with a first opening with a first diameter and a second end with a second opening with a second diameter smaller than the first opening, wherein the dielectric tube has a first gas passage in a wall of the dielectric tube extending from the first end of the dielectric tube to the second end of the dielectric tube, wherein the dielectric tube has an end cap with an internal gas passage that interfaces with the second end and extends the internal gas passage into a first end of the second opening, and wherein the second opening has a nozzle at a second end inside of the dielectric tube.

20. A method of etching a substrate in a single process chamber, comprising: generating a high power inductively coupled plasma in a process volume of a process chamber using a planar coil set positioned about a central axis of the process chamber and above the process volume when commanded by a controller of the single process chamber, wherein the high power inductively coupled plasma uses approximately 3kW or higher of RF power; etching the substrate with ions generated with the high power inductively coupled plasma; generating a low power inductively coupled plasma in a dielectric tube positioned vertically along the central axis and perpendicular to the planar coil set using a vertical coil set surrounding the dielectric tube when commanded by the controller of the single process chamber, wherein the low power inductively coupled plasma uses approximately 500W or lower of RF power; and etching the substrate with radicals generated with the low power inductively coupled plasma.241613959_1

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