US20170110292A1 - Tunable gas delivery assembly with internal diffuser and angular injection - Google Patents

Abstract

An apparatus for providing processing gases to a process chamber with improved uniformity is disclosed. One embodiment provides a gas delivery assembly. The gas delivery assembly includes a hub, a nozzle, and one or more gas diffusers disposed in the nozzle. The nozzle has a cylindrical body with a side wall and a top surface. A plurality of injection passages are formed inside the nozzle to deliver processing gases into the process chamber via a plurality of outlets disposed in the side wall. The injection passages are configured to direct process gases out of each outlet disposed in the side wall in a direction which is not radially aligned with a centerline of the hub.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• This application is a divisional application of co-pending U.S. patent application Ser. No. 13/959,801, filed on Aug. 6, 2013, (which is related to U.S. patent application Ser. No. 13/790,735, filed Mar. 8, 2013) which claims benefit of U.S. Provisional Patent Application Ser. No. 61/768,901, filed on Feb. 25, 2013. Each of aforementioned patent applications are incorporated herein by reference.
BACKGROUND
• Field
• Embodiments of the present invention generally relate to a substrate processing system. More particularly, embodiments of the present invention relate to an apparatus for providing processing gases to a process chamber with improved uniformity.
• Description of the Related Art
• During manufacturing of microelectronic devices, inductively coupled plasma reactors are used in various processes. Conventional inductively coupled plasma reactors generally include a vacuum chamber having a side wall and a ceiling, a workpiece support pedestal within the chamber and generally facing the ceiling, a gas inlet capable of supplying one or more processing gases into the chamber, and one or more coil antennas overlying the ceiling. A gas inlet generally includes one or more gas lines coupled to a gas delivery assembly with a plurality of outlets.
• The gas delivery assembly generally includes a hub, a nozzle, and outlets disposed in the side wall of the nozzle. Typically there is a vacuum pump disposed in the vacuum chamber to maintain the vacuum environment inside the chamber. It has been observed that in certain applications or chamber designs, there is a skew in the distribution of processing gas.
• Therefore, there is a need for an improved apparatus for delivering processing gas with improved uniformity.
SUMMARY
• Embodiments of the present invention relate to an apparatus for providing processing gases to a process chamber with improved uniformity. One embodiment of the present invention provides a gas delivery assembly. The gas delivery assembly includes a nozzle and one or more gas diffusers disposed in the nozzle. The nozzle has a cylindrical body with a side wall and a top surface. A plurality of injection passages are formed inside the nozzle to deliver processing gases into the process chamber via a plurality of outlets disposed in the side wall. The injection passages are configured to direct process gases out of each outlet disposed in the side wall in a direction which is not radially aligned with a centerline of the hub.
• In one embodiment, a gas delivery assembly is disclosed. The gas delivery assembly includes a nozzle having a cylindrical body with a side wall and a top surface, a first trench disposed in the top surface, and a first diffuser disposed in the first trench. A first plenum is formed between the first diffuser and a bottom of the first trench. The gas delivery assembly further includes a plurality of outer injection passages formed within the nozzle. Each of the outer injection passages extends from the bottom of the first trench to a first location inside the nozzle that is a first distance away from the top surface. The gas delivery assembly further includes a connecting passage connecting each of the outer injection passages to a first outlet disposed in the side wall of the nozzle. The connecting passage is substantially parallel to a bottom of the nozzle and is not radially aligned with a centerline of the nozzle.
• In another embodiment, a substrate processing system is disclosed. The substrate processing system includes a chamber body defining a processing volume and a chamber lid having a central opening. The substrate processing system further includes a substrate support disposed in the processing volume and a gas delivery assembly having a hub and a nozzle disposed over the chamber lid. A portion of the nozzle is positioned in the processing volume through the central opening in the chamber lid. The nozzle includes a cylindrical body having a side wall, a top surface having one or more trenches, and a gas diffuser disposed inside each trench.
BRIEF DESCRIPTION OF THE DRAWINGS
• So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, 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 typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.
• FIG. 1 schematically illustrates a sectional view of a plasma processing system according to one embodiment of the invention.
• FIG. 2 is an enlarged sectional view of a gas delivery assembly according to one embodiment of the invention.
• FIG. 3A is an isometric view of a nozzle according to one embodiment of the invention.
• FIG. 3B is a partial sectional view of the nozzle ofFIG. 3A.
• FIG. 3C is a top view of the nozzle ofFIG. 3A.
• FIG. 3D is a sectional view of the nozzle ofFIG. 3A taken throughsection line3C depicted inFIG. 2.
• 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 disclosed in one embodiment may be beneficially utilized on other embodiments without specific recitation.
DETAILED DESCRIPTION
• Embodiments of the present invention generally relate to an apparatus for providing processing gases to a process chamber with improved uniformity. More particularly, embodiments of the present invention provide a gas delivery assembly including a hub for receiving one or more gases from a source, a nozzle for injecting the one or more gases to a process chamber through a plurality of injection passages and one or more gas diffusers disposed in a top surface of the nozzle. The gas diffusers create a small pressure head when the nozzle is coupled to the hub, thus the processing gases received from a single source can have uniform flow through multiple injection points.
• FIG. 1 schematically illustrates a sectional view of asubstrate processing system100, for processing a variety of substrates and accommodating a variety of substrate sizes, for example, a substrate diameter of up to about 300 mm or 450 mm. Thesubstrate processing system100 includes achamber body102 having aprocessing volume104 defined therein. Thechamber housing assembly102 may includesidewalls106 and achamber lid108. Asubstrate support assembly110 may be disposed in theprocessing volume104. Thesubstrate support assembly110 supports asubstrate112 during processing. Aslit valve opening144 may be formed in thechamber wall106 to allow a robot (not shown) to move substrates in and out of theprocessing volume104. Aslit valve door148 may be used to selectively close theslit valve opening144. A plurality of lift pins146 may be selectively extended from thesubstrate support assembly110 to facilitate substrate transfer between the robot and thesubstrate support assembly110. In one embodiment, thesubstrate support assembly110 may include anelectrostatic chuck113 for securing thesubstrate112 thereon during processing.
• Thechamber lid108 has anopening116 to allow entrance of one or more processing gases. Theopening116 may be a central opening located near acenterline118 of thesubstrate processing system100 and correspond to a center of thesubstrate112 being processed.
• Agas delivery assembly120 is disposed over thechamber lid108 through theopening116. Thegas delivery assembly120 may be connected to agas source124 through one or moregas input lines122 to supply one or more processing gases to theprocessing volume104. In one embodiment, the one or more processing gases may exit theprocessing volume104 via apumping channel138 formed in aliner140 disposed inside theprocessing volume104. The pumpingchannel138 may be in fluid communication with avacuum pump142. Alternatively, thevacuum pump142 may be connected to theprocessing volume104 directly.
• Asensor126 may be disposed over thechamber lid108 and configured to monitor thesubstrate112 in theprocessing volume104 through thegas delivery assembly120. Thesensor126 may be connected to asystem controller128 to provide feedback for process control.
• Thesystem controller128 comprises a central processing unit (CPU) (not shown), a memory (not shown), and support circuits (not shown) for the CPU and facilitates control of the components of theprocess chamber100. Thesystem controller128 may be one of any form of general-purpose computer processor that can be used in an industrial setting for controlling various chambers and sub-processors. The memory of the CPU may be one or more of readily available memory such as random access memory (RAM), read only memory (ROM), floppy disk, hard disk, or any other form of digital storage, local or remote. The support circuits are coupled to the CPU for supporting the processor in a conventional manner. These circuits include cache, power supplies, clock circuits, input/output circuitry and subsystems, and the like. The inventive method is generally stored in the memory or other computer-readable medium accessible to the CPU as a software routine. Alternatively, such software routine may also be stored and/or executed by a second CPU (not shown) that is remotely located from the hardware being controlled by the CPU.
• Optionally, thesubstrate processing system100 may include anantenna assembly130 disposed over thechamber lid108. Theantenna assembly130 is configured to generate plasma in theprocessing volume104. Theantenna assembly130 may include one or more solenoidal interleaved coil antennas disposed coaxial with thecenterline118 of thesubstrate processing system100. Aheater assembly132 may be disposed over thechamber lid108. Theheater assembly132 may be secured to thechamber lid108 by clampingmembers134,136.
• Thegas delivery assembly120 is configured to supply one or more processing gases to theprocessing volume104 in a uniform manner.FIG. 2 is an enlarged sectional view of thegas delivery assembly120 disposed on thechamber lid108 with the clampingmembers134,136 and theheater assembly132 removed. In the embodiment ofFIG. 2, thecenterline118 of theprocessing system100 is also the centerline of thegas delivery assembly120.
• As shown inFIG. 2, thegas delivery assembly120 includes ahub210, anozzle230 and one ormore gas diffusers250 disposed in thenozzle230. When assembled, thenozzle230 is disposed through theopening116 of thechamber lid108. Thenozzle230 may have aflange232 for mounting thenozzle230 on thechamber lid108. A portion of thenozzle230 protrudes into theprocessing volume104 through theopening116 to deliver processing gas to theprocessing volume104. Thehub210 is positioned on thechamber lid108 covering theopening116 and thenozzle230. Thehub210 is disposed over thenozzle230 and provides an interface between thegas input lines122 and thenozzle230.
• Thehub210 has a body shaped to enclose theopening116 and interface with thenozzle230. The body has an outer surface facing the exterior environment and abottom surface213 for contacting with thenozzle230 and thechamber lid108. In one embodiment, the body is substantially circular and concentric with thecenterline118. The body has anouter channel206 and aninner channel208. In one embodiment, both inner andouter channels208,206 are circular and theouter channel206 is arranged radially outward of theinner channel208. In one embodiment, theouter channel206 and theinner channel208 have different heights in the body. One ormore inlet passages212a,212bare formed through the body and connected to theouter channel206 and theinner channel208. Because the outer andinner channels206,208 have different heights, theinlet passage212bconnected to the innercircular channel208 does not disrupt, e.g., is isolated from, theouter channel206. The one ormore inlet passages212a,212bare adapted to connect with the one or more gas input lines122. In one embodiment, the one ormore inlet passages212a,212bare non-symmetrical relative to thecenterline118.
• Thetop surface231 of thenozzle230 has one ormore trenches260 and thegas diffusers250 are disposed inside at least one of the trenches260 (detail described below). Agland226 may be formed in thebottom surface213 of thehub210 to receive aseal276. When assembled, theglands226 and theseals276 surround theopening116 of thechamber lid108 and theseal276 contacts thechamber lid108 to form an air tight seal between theprocessing volume104 and the exterior environment. Anothergland278 may be formed between theinner channel208 and theouter channel206 to receive aseal280 to form an air tight seal between the two channels.
• In one embodiment, thegas injection assembly120 includes anobservation window270. The body of thehub210 may have a throughhole222 and thenozzle230 may be a hollow cylinder having acentral opening240. Theobservation window270 may be disposed between thehub210 and thenozzle230. In one embodiment, thenozzle230 may have arecess242 for supporting theobservation window270. Thehub210 may have agland272 formed to receive aseal274 to provide a vacuum seal between thehub210 and theobservation window270. In one embodiment, theobservation window270 is fabricated from quartz.
• Thenozzle230 has a cylindrical body with aside wall228 and atop surface231 for contacting with thebottom surface213 of thehub210. Thenozzle230 has a plurality ofinner injection passages238 and a plurality ofouter injection passages236 for injecting one or more processing gases from the outer andinner channels206,208 of thehub210 to theprocessing volume104. In one embodiment, theouter injection passages236 are arranged radially outward of theinner injection passages238. The outer andinner injection passages236,238 may have outlets at various positions to achieve gas injection. In one embodiment, as shown inFIG. 2, theouter injection passages236 haveoutlets306 disposed in theside wall228 and are connected to theoutlets306 by connectingpassages330. Theinner injection passages238 haveoutlets350 disposed in abottom surface235 of thenozzle230 and directed downward from thenozzle230. In one embodiment, the outer andinner injection passages236,238 are evenly distributed in azimuthal orientation (e.g., in an evenly distributed polar array).
• FIGS. 3A-3D illustrate thenozzle230 according to various embodiments of the invention.FIG. 3A is an isometric view of thenozzle230, whileFIG. 3B is a partial sectional view of thenozzle230. Thetop surface231 of thenozzle230 has anouter trench302 and aninner trench304. In one embodiment, the outer andinner trenches302,304 are circular and concentric with thecenterline118. The plurality ofoutlets306 of theouter injection passages236 are disposed in theside wall228. In one embodiment, theoutlets306 are disposed evenly along the circumference of theside wall228.
• As shown inFIG. 3B, thegas diffusers250a,250bare disposed inside the outer andinner trenches302,304, respectively. Thegas diffusers250a,250bare spaced frombottoms352,354 of the outer andinner trenches302,304, thus, creatingplenums356,358 between thegas diffusers250a,250bandbottoms352,354 of the outer andinner trenches302,304 so that the processing gases may be evenly distributed into theinjection passages236,238. Thegas diffusers250a,250bmay be any suitable gas permeable material or structure. In one embodiment, as shown inFIG. 3A, thegas diffusers250a,250bhave a plurality ofholes308. Thegas diffusers250a,250bmay be made of alumina or the same material as thenozzle230. In one embodiment, thenozzle230 and thegas diffusers250a,250bare made of ceramic material. When thehub210 and thenozzle230 are assembled, theinner trench304 of thenozzle230 is aligned with theinner channel208 of thehub210, and theouter trench302 of thenozzle230 is aligned with theouter channel206 of thehub210.
• As shown inFIG. 3B, theouter injection passage236 extends from thebottom352 of theouter trench302 to a location within thenozzle230 that is a distance away from thetop surface231. Theinner injection passage238 extends from thebottom354 of theinner trench304 to a location within thenozzle230 that is a distance away from thetop surface231. In one embodiment, theinner injection passage238 extends further into thenozzle230 than theouter injection passage236.
• FIG. 3C is a top view of thenozzle230, in which thegas diffusers250a,250bare transparent for better illustration. As described above, thenozzle230 has the plurality ofouter injection passages236 and the plurality ofinner injection passages238 disposed therein. In one embodiment, theouter injection passages236 are arranged radially outward of theinner injection passages238. As shown inFIG. 3C, theouter injection passages236 haveinlets320 disposed at the bottom of theouter trench302, and theinner injection passages236 haveinlets310 disposed at the bottom of theinner trench304. Theinlets310,320 may be disposed evenly inside the inner andouter trenches304,302. The area of one of the plurality ofholes308 of thegas diffusers250a,250bmay be smaller than the surface area of one of theinlets310,320. In one embodiment, the total area of theholes308 of thediffuser250aequals the total surface area of theinlets320, and the total area of theholes308 of thediffuser250bequals the total surface area of theinlets310. Thegas diffusers250a,250bcreate a small pressure head when thenozzle230 is coupled to thehub210, thus the processing gases received from asingle gas source124 can have uniform flow through multiple injection points.
• FIG. 3D is a sectional view of thenozzle230 without thegas diffusers250. As shown inFIG. 2, theouter injection passages236 extends from the bottom of theouter trench302 to a distance inside thenozzle230 from thetop surface231, and theoutlets306 of theouter injection passages236 are disposed in theside wall228. As shown inFIG. 3D, eachoutlet306 and the correspondingouter injection passage236 are connected by a connectingpassage330. The connectingpassage330 is not perpendicular to a tangent340 of theside wall228 at the outlet306 (e.g., the angle “A” inFIG. 3D does not equal to 90 degrees). In other words, the connectingpassages330 are not radially aligned with thecenterline118 of thechamber body102, which is also the centerline of thehub210,nozzle230, andgas diffusers250a,250b.In one embodiment, the angle “A” ranges from about 15 degrees to about 60 degrees. The processing gases exiting theoutlet306 are directed in the same direction defined by the connectingpassage330. If the angle “A” is 90 degrees, then the processing gases coming out of the outlet that is facing thevacuum pump142 may travel at a faster speed compare to the processing gases coming out of all other outlets. By changing the angle “A” to an angle other than 90 degrees, the processing gases are coming out of each outlet at substantially the same speed, thus creating a more uniform gas flow inside the process chamber.
• In summary, by adding one or more internal gas diffusers in the nozzle of a gas delivery assembly along with changing the angle of processing gases coming out of outlets disposed along the circumference of the side wall of the nozzle, a more uniform flow of the processing gases is achieved.
• While the foregoing is directed to embodiments of the present 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.

Claims (20)

What is claimed is:

1. A gas delivery assembly, comprising:

a cylindrical body having a side wall and a top surface;

a first trench disposed in the top surface, wherein the first trench includes a bottom; and

a first diffuser disposed in the first trench, wherein a first plenum is formed between the first diffuser and the bottom of the first trench.

2. The gas delivery assembly ofclaim 1, further comprising a second trench disposed in the top surface of the nozzle, wherein the second trench includes a second bottom.

3. The gas delivery assembly ofclaim 2, further comprising a second diffuser disposed in the second trench, wherein a second plenum is formed between the second diffuser and the bottom of the second trench.

4. The gas delivery assembly ofclaim 3, further comprising a plurality of outer injection passages formed within the cylindrical body, wherein each of the outer injection passages extends from the bottom of the first trench to a first location inside the cylindrical body that is a first distance away from the top surface.

5. The gas delivery assembly ofclaim 4, further comprising a plurality of inner injection passages formed within the cylindrical body, wherein each of the inner injection passages extend from the bottom of the second trench to a second location inside the cylindrical body that is a second distance away from the top surface.

6. The gas delivery assembly ofclaim 5, wherein the second distance is greater than the first distance.

7. The gas delivery assembly ofclaim 5, further comprising a connecting passage connecting each of the outer injection passages to an outlet disposed in the side wall of the cylindrical body, wherein the connecting passage is substantially parallel to a bottom of the cylindrical body.

8. The gas delivery assembly ofclaim 7, wherein an angle between the connecting passage and a tangent of the side wall at a corresponding outlet ranges from about 15 degrees to about 60 degrees.

9. A gas delivery assembly, comprising:

a hub, comprising:

an inner channel; and

an outer channel; and

a nozzle coupled to the hub, wherein the nozzle comprises:

a cylindrical body having a side wall and a top surface;

a first trench disposed in the top surface, wherein the first trench includes a bottom;

a second trench disposed in the top surface, wherein the second trench includes a bottom, wherein the inner channel of the hub is aligned with the second trench of the nozzle and the outer channel of the hub is aligned with the first trench of the nozzle; and

a first diffuser disposed in the first trench, wherein a first plenum is formed between the first diffuser and the bottom of the first trench.

10. The gas delivery assembly ofclaim 9, further comprising a second diffuser disposed in the second trench, wherein a second plenum is formed between the second diffuser and the bottom of the second trench.

11. The gas delivery assembly ofclaim 10, further comprising a plurality of outer injection passages formed within the nozzle, wherein each of the outer injection passages extends from the bottom of the first trench to a first location inside the nozzle that is a first distance away from the top surface.

12. The gas delivery assembly ofclaim 11, further comprising a plurality of inner injection passages formed within the nozzle, wherein each of the inner injection passages extend from the bottom of the second trench to a second location inside the nozzle that is a second distance away from the top surface.

13. The gas delivery assembly ofclaim 12, wherein the second distance is greater than the first distance.

14. The gas delivery assembly ofclaim 13, further comprising a connecting passage connecting each of the outer injection passages to an outlet disposed in the side wall of the nozzle, wherein the connecting passage is substantially parallel to a bottom of the nozzle.

15. The gas delivery assembly ofclaim 14, wherein an angle between the connecting passage and a tangent of the side wall at a corresponding outlet ranges from about 15 degrees to about 60 degrees.

16. A gas delivery assembly, comprising:

a nozzle comprising a cylindrical body having a side wall and a top surface;

a first trench disposed in the top surface;

a first diffuser disposed in the first trench, wherein a first plenum is formed between the first diffuser and a bottom of the first trench;

a plurality of outer injection passages formed within the nozzle, wherein each of the outer injection passages extends from the bottom of the first trench to a first location inside the nozzle that is a first distance away from the top surface; and

a connecting passage connecting each of the outer injection passages to a first outlet disposed in the side wall of the nozzle, wherein the connecting passage is substantially parallel to a bottom of the nozzle.

17. The gas delivery assembly ofclaim 16, further comprising a second trench disposed in the top surface of the nozzle.

18. The gas delivery assembly ofclaim 17, further comprising a second diffuser disposed in the second trench, wherein a second plenum is formed between the second diffuser and a bottom of the second trench.

19. The gas delivery assembly ofclaim 18, wherein the first and second diffusers are fabricated from alumina.

20. The gas delivery assembly ofclaim 18, wherein the first and second diffusers are fabricated from a same material as the nozzle.

Images