Chamber lid for dissipating charges

Abstract

Disclosed herein are a chamber lid, a processing chamber having the chamber lid, and a method for reducing a particle generation. The chamber lid includes a body including a plasma-facing side; and a protective surface disposed on the plasma- facing side and including a conductive layer. The conductive layer has a thickness of no greater than about 1 um.The protective surface further includes a chemically resistant layer disposed on the conductive layer and having a thickness of no greater than about 5 um. The reactive ion etching chamber includes a plurality of side walls coupled with the chamber lid, and a conductive liner connected to the ground. The conductive layer of the chamber lid is coupled with the conductive liner. The method includes discharging electrons accumulated on the chamber lid via the conductive layer and the conductive liner.

Description

CHAMBER LID FOR DISSIPATING CHARGESBACKGROUNDField

[0001] The present disclosure relates to a chamber lid of a semiconductor processing system, and, more specifically, relates to a chamber lid including a conductive layer for dissipating electronic charges.Description of the Related Art

[0002] Plasma is used in many semiconductor processes, including deposition of layers, etch of materials, and cleaning of chambers. Plasma includes charged particles, such as electrons and ions, which can be directed to targeted surfaces by RF power and / or bias voltages. In a reactive ion etching chamber, plasma is generated in a processing volume between a chamber lid and a substrate. Ions in the plasma are accelerated by a bias voltage toward the substrate for etching. Certain electrons can be accelerated toward the chamber lid and accumulated on the chamber lid. These accumulated electron on the chamber lid can cause several problems, including sputtering of the chamber lid by ions, which can generate unwanted particles inside the processing chamber.

[0003] Thus, a need exists for an improved chamber lid of a processing chamber capable of reducing the generation of unwanted particles.SUMMARY

[0004] Disclosed herein are a chamber lid, a processing chamber comprising the chamber lid, and a method for reducing unwanted particles in the processing chamber. In an embodiment, the chamber lid includes a body comprising a plasma-facing side; and a protective surface disposed on the plasma-facing side and including a conductive layer. The conductive layer has a thickness of no greater than about 1 urn. The protective surface further includes a chemically resistant layer disposed on the conductive layer and having a thickness of no greater than about 5 urn or 10 urn.

[0005] In an embodiment, the reactive ion etching chamber includes a plurality of side walls coupled with a chamber lid, and a conductive liner connected to the ground. The chamber lid includes a body having plasma-facing side; and a protective surface disposed on the plasma-facing side. The protective surface includes a conductive layer coupled with the conductive liner and having a thickness of no greater than about 1 urn; and a chemically resistant layer disposed on the conductive layer and having a thickness of no greater than about 5 urn or 10 urn.

[0006] In an embodiment, the method includes disposing a chamber lid in the processing chamber, the chamber lid comprising a conductive layer deposited on a plasma-facing side of the chamber lid and a chemically resistant layer deposited on the conductive layer, the conductive layer having a thickness of no greater than 1 urn; connecting the conductive layer to a conductive liner of a processing chamber; and discharging charges, such as electrons, negative radicals, accumulated on the chamber lid via the conductive layer of the chamber lid and the conductive liner.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only exemplary embodiments and are therefore not to be considered limiting of its scope, may admit to other equally effective embodiments.

[0008] Figure 1 illustrates a schematic top view of a processing system, according to an embodiment of the present disclosure.

[0009] Figure 2 illustrates a schematic cross-sectional view of a reactive ion etching chamber having an improved chamber lid, according to an embodiment of the present disclosure.

[0010] Figure 3a illustrates a schematic cross-sectional view of a chamber lid having one or more protective layers, according to an embodiment.

[0011] Figure 3b illustrates a schematic cross-sectional view of a chamber lid having one or protective layers with varying oxidation levels, according to an embodiment.

[0012] Figure 4a illustrates a schematic cross-sectional view of a chamber lid, according to an embodiment.

[0013] Figure 4b illustrates a schematic bottom view of a chamber lid, according to an embodiment

[0014] Figure 5 illustrates a schematic cross-sectional view of a RIE chamber, according to an embodiment.

[0015] Figure 6 illustrates a method for protecting a chamber lid, according to an embodiment.

[0016] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.DETAILED DESCRIPTION

[0017] The disclosure contemplates that terms such as “couples,” “coupling,” “couple,” and “coupled” may include but are not limited to welding, fusing, melting together, interference fitting, and / or fastening such as by using bolts, threaded connections, pins, and / or screws. The disclosure contemplates that terms such as “couples,” “coupling,” “couple,” and “coupled” may include but are not limited to integrally forming. The disclosure contemplates that terms such as “couples,” “coupling,” “couple,” and “coupled” may include but are not limited to direct coupling and / or indirect coupling, such as indirect coupling through components such as links, blocks, and / or frames.

[0018] Disclosed herein are a chamber lid, a processing chamber having the chamber lid, and a method for reducing unwanted particles in a RIE chamber. In an embodiment, the chamber lid includes a dielectric body covered by a protectivesurface. The protective surface includes a conductive layer deposited on a chamber body. The conductive layer is configured to dissipate charges to a grounded part of the processing chamber. In an embodiment, the charges include electrons and negative radicals. In another embodiment, the charges include positive radicals. The thickness of the conductive layer is selected to avoid any substantial amount of RF power loss in the RIE chamber. In an example, the conductive layer is made of yttrium with a thickness no greater than 1 urn. The conductive layer cause no more than about 1 percent or 0.1 percent of RF power loss at 10 MHz frequency.

[0019] The protective surface also includes a chemically-resistant layer covering the conductive layer. The chemically-resistance layer protects the conductive layer from the etch chemistry in the RIE chamber. The chemically-resistant layer may include a plurality of slits allowing electronic charges to reach the underneath conductive layer. The chemically-resistance layer has resistance determined to maintain a normal generation of the plasma.

[0020] A chamber lid as set forth of the present disclosure can discharge electronic charges on the chamber lid, thus keeping a sheath voltage adjacent to the chamber lid low and reducing the generation of unwanted particles in the RIE chamber. The chamber lid will not require a substantial adjustment of parameters for the plasma generation.

[0021] In an embodiment, the RIE chamber includes a chamber lid as set forth in the present disclosure. The chamber lid is electrically coupled with a grounded part of the RIE chamber to discharge charges to the ground. The method for reducing unwanted particles in a RIE chamber utilizes and grounds the chamber lid as set forth in the present disclosure in the RIE chamber.

[0022] Figure 1 illustrates a schematic top view of a plasma processing system 100, according to one or more embodiments. According to an embodiment, the processing system 100 includes a chamber having a chamber lid for dissipating charges as described in the present disclosure. The processing system 100 includes one or more load lock chambers 122 (two are shown in Figure 1 ), a processing platform 104, a factory interface 102, and a controller 144. In one or moreembodiments, the processing system 100 may be adapted for use in a CENTURA® integrated processing system provided by Applied Materials, Inc., located in Santa Clara, California. It is contemplated that other processing systems (including those from other manufacturers) may be adapted to benefit from the present disclosure.

[0023] The processing platform 104 includes a plurality of processing chambers 110, 112, 120, 128, and a transfer chamber 136. Each of the processing chambers 110, 112, 120, 128 is coupled to the transfer chamber 136. The transfer chamber 136 can be maintained under vacuum. The factory interface 102 is coupled to the transfer chamber 136 through the load lock chambers 122. Two load lock chambers 122 are shown in Figure 1. The load lock chambers 122 are used to transfer substrates from an ambient (e.g., atmospheric) pressure environment of the factory interface 102 to the vacuum environment of the transfer chamber 136.

[0024] In one or more embodiments, the factory interface 102 includes at least one docking station 109 and at least one factory interface robot 114 to facilitate the transfer of substrates 124. The docking station 109 is configured to accept one or more front opening unified pods (FOUPs). Two FOURS 106A, 106B are shown in the implementation of Figure 1. The factory interface robot 114 has a blade 116 that is configured to transfer one or more substrates from the FOUPS 106A to the load lock chambers 122.

[0025] Each of the load lock chambers 122 has a first port interfacing with the factory interface 102 and a second port interfacing with the transfer chamber 136. The transfer chamber 136 has a vacuum robot 130 disposed therein. The vacuum robot 130 has one or more blades 134 (two are shown in Figure 1 ) capable of transferring the substrates 124 between the load lock chambers 122 and the processing chambers 110, 112, 120, and 128.

[0026] The controller 144 is coupled to the processing system 100 and is used to control processes and methods, such as the operations of the methods described herein (for example the operations of the methods as described in other parts of the present disclosure). The controller 144 includes a central processing unit (CPU) 138,a memory 140 containing instructions, and support circuits 142 for the CPU. The controller 144 controls various items directly, or via other computers and / or controllers.

[0027] Figure 2 illustrates a schematic cross-sectional view of a plasma processing chamber 200. In one embodiment, the processing chamber 200 functions as a reactive ion etch (RIE) chamber, or other plasma etch chamber. In some embodiments, the processing chamber 200 may function as a plasma enhanced chemical vapor deposition (PECVD) chamber, a plasma enhanced physical vapor deposition (PEPVD) chamber, or a plasma enhanced atomic layer deposition (PEALD) chamber. In some embodiments, the plasma processing chamber 200 may function as a plasma treatment chamber, or a plasma based ion implant chamber, for example a plasma doping (PLAD) chamber.

[0028] The plasma processing chamber 200 includes a plasma source 204, such as an inductively coupled plasma (ICP) source, electrically coupled to an RF power supply 214 via an RF matching circuit 212. In other embodiments, the plasma source 204 is a capacitively coupled plasma (CCP) source, such as a plasma electrode disposed in the processing volume facing the substrate support where the plasma electrode is electrically coupled to an RF power supply.

[0029] The plasma processing chamber 200 includes a chamber body 206 and a chamber lid 208. The chamber lid 208 is disposed on the chamber body 206 and configured to protect a processing volume 216. One or more process gases are introduced into the processing volume 216 from a process gas source 210 via a nozzle 228 (or showerhead). The plasma source 204, which may be one or more inductive coils in one embodiment, is disposed on the chamber lid 208 outside of the processing chamber 200. The RF power supply 214 and the plasma source 204 are used to form and maintain a plasma using the process gases and inductive energy in the processing volume 216.

[0030] To isolate the processing volume from the plasma source 204, the chamber lid 208 includes a dielectric body having a plasma facing surface covered by a protective coating. The dielectric body may be made of any suitable dielectric materials. Suitable dielectric materials may include a bulk sintered ceramic material,a corrosion resistant metal oxide, or metal nitride material, for example aluminum oxide (AI2O3), aluminum nitride (AIN), titanium oxide (TiO), titanium nitride (TiN), yttrium oxide including YO and Y2O3, mixtures thereof, or combinations thereof, among other materials.

[0031] In an embodiment, the protective coating includes one or more layers of conductive materials, which are disposed on a plasma-facing surface of the chamber lid. The one or more layers of the conductive materials are configured to dissipate charges caused by the impinging electrons coming from the plasma. The conductive materials may include silicon, silicon carbide, copper, yttrium, aluminum, doped silicon nitride, or any other suitable conductive materials.

[0032] In an embodiment, the protective coating includes one or more layers of chemically resistant materials covering the one or more layers of conductive materials. The one or more layers of chemically resistant materials may be any material that can sufficiently resist the plasma chemistry in the processing chamber. The chemically resistant materials may include AIN, yttrium oxide, AI2O3, and other suitable materials. The one or more layers of chemically resistant materials are configured to have a low resistance such that electronic charges can quickly reach the one or more conductive layer covered by the chemically resistant materials.

[0033] The processing volume 216 is fluidly coupled to one or more vacuum pumps 226, through a vacuum outlet 224, which maintain the processing volume 216 at sub- atmospheric conditions and evacuate processing, and / or other gases, therefrom. A substrate support assembly 202 is disposed in the processing volume 216. The substrate support assembly 202 includes an ESC 222 for supporting and biasing a substrate 230. The ESC 222 includes an electrode 220 embedded therein. The electrode 220 is coupled with a power source 232 and utilized for both biasing and clamping the substrate 230. The electrode 220 is formed of an electrically conductive material, such as one or more metal meshes, foils, plates, or combinations thereof.

[0034] Figure 3a illustrates a schematic cross-sectional view of a chamber lid 300, according to an embodiment. The chamber lid 300 includes a lid body 302 and a protective surface 314. The lid body 302 extends between and are supported bychamber walls and is configured to enclose the processing chamber. In an embodiment, the protective surface 314 include a conductive layer 304 and a chemically resistant layer 306. The chamber body 302 may be formed of a dielectric material and have any shape. The chamber body 302 includes an external surface 312 facing the plasma source 204 (shown in Figure 2) and an internal (plasma-facing) surface 310 facing the processing volume 216.

[0035] The conductive layer 304 is coated on the plasma-facing surface 310 of the chamber lid 300. The conductive layer 304 is connected to ground. The conductive layer 304 can quickly dissipate charges to the ground. The conductive layer 304 is grounded either directly or via other conductive parts of the processing chamber. In an embodiment, the conductive layer 304 is selected from a material that has sufficient conductivity and can be deposited in thin layers. The material of the conductive layer 304 may include doped aluminum nitride, silicon carbide, silicon, yttrium, or any other suitable materials. The conductive layer 304 may substantially cover the entire plasma-facing surface 310. In an embodiment, the conductive layer 304 has a thickness of no more than 5 urn, no more than 2 urn, or no more than 1 urn. The conductive layer 304 is configured to cause a relatively low loss of RF power for plasma generation. In an embodiment, the RF power loss caused by the conductive layer 304 is no greater than 1 percent, no greater than 0.1 percent, or no greater than 0.01 percent.

[0036] The chemically resistant layer 306 is disposed on top of the conductive layer 304, such that the conductive layer 304 is disposed between the chemically resistant layer 306 and the plasma-facing surface 310 of the lid body 302. The conductive layer 304 is comprised of a material selected to have sufficient resistance to the etch chemistry in the processing volume 216. In an embodiment, the chemically resistant layer 306 may be made of a material that is resistant to the etch chemistry. For example, the chemically resistant layer 306 may be made of aluminum nitride or yttrium oxide. In an embodiment, the chemically resistant layer 306 is configured to have a proper resistance to allow electronic charges generated during a normal plasma generation to pass through and reach the conductive layer 304. The resistance of the chemically resistant layer 306 may be determined according to thegeometry and electrical potential of the chamber lid, the ion current during a plasma process, material properties of the chemical resistant layer 306, and other parameters. In an example, a chamber lid of a diameter of about 30-50 cm and an ion current of about 0.5 A to about 2.5 A, the chemically resistant layer 306 may have a resistance between 10 ohms and 1000 ohms or between 10 ohms and 100 ohms (measured along a thickness of the chemically resistant layer) to maintain the ion current during the plasma generation. Thus, parameters for the plasma generation may not be substantially adjusted after the chemically-resistant layer 306 is included in the chamber lid. The chemically resistant layer 306 may have a thickness between 10 nm and 100 urn, or between 100 nm and 10 urn, or between 1 urn and 5 urn depending on the electrical resistance of the material.

[0037] In an embodiment, the conductive layer 304 connects to the ground 308 via one or more other grounded parts of the processing chamber. To have an electrical connection with other grounded parts, the resistant layer 306 may leave contact areas between the conductive layer 304 and other grounded parts uncovered. For example, circumferential areas of the conductive layer 304 may be exposed and contact with other grounded parts of the processing chamber. Alternatively, the conductive layer 304 may connect to the ground 308 directly.

[0038] Figure 3b illustrates a chamber lid 320 having a protective surface 322 whose electrical resistance and chemical resistance can be controlled according to a level of the oxygen content, according to an embodiment. The protective surface 322 has a chemically resistant portion 328 and a conductive portion 326. In an embodiment, the chemically resistant portion 328 and the conductive portion 326 contain a common element, such as yttrium. In another example, the common element between the conductive portion 326 and the chemically resistant portion 328 may include yttrium or other suitable rare-earth element.

[0039] In an embodiment, the protective surface 322 may be formed by pure yttrium, which is conductive. The chemically resistant portion 328 may be formed by yttrium oxide, which is less conductive and has stronger resistance to the etch chemistry. In an embodiment, a gradient 324 for the oxygen content is formed in the chemically resistant portion 328. For example, the oxygen content decreases fromthe exposed surface 332 to the boundary 330 between the conductive portion 326 and the resistant portion 328. The higher concentration of oxygen adjacent to the exposed surface 332 can increase the resistance to the etch chemistry, while the decreasing concentration of oxygen toward the boundary 330 can increase the electrical conductivity.

[0040] In an embodiment, the protective surface 322 can be formed by a CVD or ALD process with varying oxygen flow rates. For example, the conductive portion 326 may be a layer of pure yttrium formed without the presence of oxygen. The protective portion 328 may be yttrium oxide formed by the similar CVD process with an increasing flow rate of oxygen. The conductive portion 326 may be less than 1 urn and the protective portion 328 may be between 1 urn and 5 urn.

[0041] Figure 4a illustrates a schematic cross-sectional view of a chamber lid 400, according to an embodiment. The chamber lid 400 includes a dielectric body 402, a conductive layer 404, and a protective layer 406. The conductive layer 404 includes a planar portion 409 substantially covering the plasma-facing surface of the dielectric body 402 and an annular portion 408 deposited at the circumferential areas of the dielectric body 402 and uncovered by the protective layer 406. The annular portion 408 may contact with other grounded parts 410. In an embodiment, the annular portion 408 is disposed further away from the substrate support assembly 202 relative to the planar portion 409. The planar portion 409 may include an annular portion 411 extending beyond the protective layer 406. The annular portion 411 can also contact with other grounded parts 410 to discharge electrons. The protective layer 406 includes a plurality of slits 412, 414 that are configured to reduce a load of the plasma source. The plurality of slits 412 and 414 expose the conductive layer 404 and are symmetrically arranged around a center 416 of the chamber lid 400. The plurality of slits 412, 414 may be arranged in a pattern according to a geometry of the plasma source to allow polarization of RF waves to pass through. For example, slits 412 form one group and are arranged according to a positive polarity of RF waves, and slits 414 form another group and are arranged according to a negative polarity of the RF waves. In an embodiment, the plurality of slits 412 and 414 form a radiating pattern that extend radially outward from the center 416, like spokes of a bicycle wheel.

[0042] Figure 5 illustrates a schematic configuration of a RIE chamber 500, according to an embodiment. The RIE chamber 500 includes a chamber lid 502 disposed above the processing volume 216. The chamber lid 502 is isolated from a second side wall 506 by a spacer 508. The chamber lid 502 is electrically connected to a grounded part 410 via the annular portion 408 (shown in Fig. 4a). The grounded part 410 may be a conductive liner 514 disposed around the processing volume 216 and configured to protect other parts of the RIE chamber 500. The conductive liner 514 is grounded and can dissipate charges from the chamber lid 502 to the ground. As shown in Figure 5, the conductive liner 514 is supported by a first side wall 510 and is protected by a second side wall 506. An ICP RF coil 504 is disposed on top of the chamber lid 502 and configured to generate a plasma in the processing volume 216. The first side wall 510 and the second side wall 506 overlap with each other at a location 512 where the conductive liner 514 couples with the first side wall.

[0043] Figure 6 illustrates a method 600 for reducing a particle generation in a processing chamber, according to an embodiment. The processing chamber includes a chamber lid as set forth in various embodiments of the present disclosure. The chamber lid includes a conductive layer deposited on a plasma-facing side of the chamber lid and a chemically resistant layer deposited on the conductive layer. The conductive layer may have a thickness of no greater than 1 urn, and the conductive layer may be grounded through a conductive liner of the processing chamber. At operation 602, processing gases are provided to the processing chamber, and a plasma is formed within the processing chamber by a plasmas source. At operation 604, a substrate is exposed to the plasma formed in the processing chamber and being processed. Charged particles, such as electrons and ions, are accelerated and may speed out of the plasma and sputter the chamber lid. At operation 606, charged particles, such as electrons or ions, accumulated on the chamber lid of the processing chamber during processing of the substrate is discharged to the ground via the conductive layer and the conductive liner, thus reducing the sputtering effect and particles that may be generated.

[0044] It is contemplated that one or more aspects disclosed herein may be combined. Moreover, it is contemplated that one or more aspects disclosed hereinmay include some or all of the aforementioned benefits. While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

Claims

What is claimed is:1 . A chamber lid for a plasma processing chamber, comprising: a body comprising a plasma-facing side and configured to protect a processing volume of the plasma processing chamber; and a protective surface disposed on the plasma-facing side and comprising a conductive layer.

2. The chamber lid of claim 1 , wherein the conductive layer is configured to couple with a conductive liner of the plasma processing chamber to discharge electrons.

3. The chamber lid of claim 1 , wherein the conductive layer includes yttrium, silicon carbide, doped aluminum nitride, or silicon.

4. The chamber lid of claim 3, wherein the conductive layer has a thickness of no greater than about 1 urn.

5. The chamber lid of claim 4, wherein the conductive layer is made of yttrium.

6. The chamber lid of claim 1 , wherein the protective surface further includes a chemically resistant layer disposed on the conductive layer.

7. The chamber lid of claim 6, wherein the chemically resistant layer has an electrical resistance between 10 ohm and 100 ohm measured along a thickness of the chemically resistant layer.

8. The chamber lid of claim 7, wherein the chemically resistant layer has a thickness between about 1 urn and about 10 urn.

9. The chamber lid of claim 6, wherein the conductive layer is made of yttrium, and the chemically resistant layer is made of yttrium oxide.

10. The chamber lid of claim 9, wherein an oxygen content of the chemically resistant layer decreases in a direction from an outer surface of the chemically resistant layer toward the body.11 . The chamber lid of claim 6, wherein the chemically resistant layer includes a plurality of slits exposing the conductive layer.

12. The chamber lid of claim 11 , wherein the plurality of slits are arranged in a pattern that extends radially outward from a center of the chamber lid.

13. A reactive ion etching chamber, comprising: a plurality of side walls; a chamber lid disposed on the side walls, and a conductive liner coupled with the side walls, wherein the chamber lid comprises: a body comprising a plasma-facing side; and a protective surface disposed on the plasma-facing side and comprising: a conductive layer disposed in contact with the conductive liner and having a thickness of no greater than about 1 urn; and a chemically resistant layer disposed on the conductive layer and having a thickness of no greater than about 10 urn.

14. The reactive ion etch chamber of claim 13, further comprising a spacer disposed between a side wall and the chamber lid.

15. The reactive ion etch chamber of claim 13, wherein the conductive layer comprises yttrium, and the chemically resistant layer comprises yttrium oxide.

16. The reactive ion etch chamber of claim 15, wherein the chemically resistant layer has an electrical resistance between 10 ohm and 100 ohm measured along a thickness of the chemically resistant layer.

17. The reactive ion etch chamber of claim 16, wherein an oxygen content of the chemical resistance layer decreases in in a direction from an outer surface of the chemically resistant layer toward the body.

18. The reactive ion etch chamber of claim 14, further comprising an RF coil disposed on top of the chamber lid.

19. The reactive ion etch chamber of claim 13, wherein the chemically resistant layer comprises a plurality of slits exposing the conductive layer.

20. A method for reducing a particle generation in a processing chamber, comprising: forming a plasma within a processing chamber; processing a substrate exposed to the plasma formed in the processing chamber; and discharging charges accumulated on a chamber lid of the processing chamber during processing of the substrate, the chamber lid comprising a conductive layer deposited on a plasma-facing side of the chamber lid and a chemically resistant layer deposited on the conductive layer, the conductive layer having a thickness of no greater than 1 urn, the conductive layer grounded through a conductive liner.

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