An injection assembly and methods for chemical vapor processing reactors

Abstract

An injection assembly for an ALD, atomic layer deposition, or CVD, chemical vapor deposition, reactor; a reactor having such an injection assembly and a method of cleaning such an injection assembly The injection assembly having a cylindrical body comprising an opening at a bottom end, the side of the cylindrical body comprising at least one injection opening, and at least one annular injector comprising an annular flow channel and an injection inlet for receiving at least one of a: plasma, etch gas, carrier gas or precursor, the annular injector being affixed around the cylindrical body to envelop the injection opening such that the injection opening, annular flow channel and injection inlet are in fluid connection.

Description

[0001] AN INJECTION ASSEMBLY AND METHODS FOR CHEMICAL VAPOR PROCESSING REACTORS

[0002] TECHNICAL FIELD

[0003] The present disclosure generally relates to injection assemblies for chemical vapor processing reactors, such as Atomic Layer Deposition (ALD) or Chemical Vapor Deposition (CVD) reactors, and associated methods.

[0004] BACKGROUND

[0005] This section illustrates useful background information without admission of any technique described herein representative of the state of the art.

[0006] While there are various injection geometries for chemical vapor processing, such as CVD and ALD, reactors, many rely on diffusion to provide the desired mixing and partial pressure distribution. Such reliance does not provide for uniform partial pressure distribution of precursor over the surface of a deposition target or substrate. Precursor utilization is thus poor, with much of the precursor traveling over the substrate to the exhaust without substantial deposition.

[0007] Chemical vapor processing methods benefit from uniform partial pressure distribution of the precursor over the substrate surface to reach uniform film thicknesses, especially over large area substrates. In addition, ALD method benefits from fast gas switching times in the reactor and accurately controlled surface temperatures of the flow channel surfaces upstream the substrate. Furthermore, the common flow path for different precursors should be minimized to reduce precursor interactions on surfaces prior to the substrate.

[0008] Therefore, there is an ongoing need to develop improved designs for injection geometries which provide for at least one of: more uniform partial pressure, fast gas switching times, accurately controlled surface temperatures and / or minimal common flow path.

[0009] SUMMARY

[0010] The present disclosure aims to provide an improved injection geometry for use in chemical vapor processing reactors, such as ALD and CVD reactors, to improve the operation of reactors using said geometry, or at least to provide an alternative to existing technology.Embodiments as described herein provide for streamlined vertical gas delivery to a substrate, with an annular injector to improve gas mixing and improved precursor utilization. Further, embodiments described here are compatible with Plasma-Enhanced Atomic Layer Deposition (PEALD), including remote plasma configurations, without the need of moving parts above the wafer. Without moving parts, fewer mechanical particles are introduced. Certain embodiments of the present disclosure aim to improve uniformity of film deposition onto substrate surfaces, particularly during single wafer deposition.

[0011] The appended claims define the scope of protection. Any examples and technical descriptions of apparatuses, products and / or methods in the description and / or drawings not covered by the claims are presented not as embodiments of the invention but as background art or examples useful for understanding the invention.

[0012] According to a first example aspect there is provided an injection assembly for a chemical vapor deposition reactor, such as an ALD, atomic layer deposition, or CVD, chemical vapor deposition, reactor; the injection assembly comprising: a cylindrical body comprising an opening at a bottom end, the side of the cylindrical body comprising at least one injection opening, and at least one annular injector comprising an annular flow channel and an injection inlet for receiving at least one of a: plasma, etch gas, carrier gas or precursor, the annular injector being affixed around the cylindrical body to envelop the injection opening such that the injection opening, annular flow channel and injection inlet are in fluid connection. Such chemical vapor injector assemblies may be, for example, for chemical vapor deposition and / or etching, atomic layer deposition and / or etching, gas phase deposition and / or etching, plasma etching.

[0013] Within some embodiments, the injection opening comprises a plurality of holes spaced around the side of the cylindrical body. In at least some embodiments the side of the cylindrical body comprises at least one wall defining at least a portion of the cylindrical body. In certain embodiments the side of the cylindrical body comprises a plurality of walls. In certain embodiments the plurality of holes are evenly spaced around the side of the cylindrical body. In at least some embodiments the plurality of holes are aligned in a line around the side of the cylindrical body.

[0014] In certain embodiments, the injection opening comprises a slit. In at least some embodiments, the slit continues around the entire circumference of the cylindrical body such that the body is split into at least two segments.According to some embodiments, the injection assembly comprises a plurality of injection openings and a plurality of annular injectors, each annular injector being affixed around the cylindrical body such that it envelops an individual injection opening such that the annular flow channel and injection inlet of each injector is in fluid connection with an individual injection opening.

[0015] In some embodiments, a portion of each annular injector forms a portion of the side of the cylindrical body.

[0016] In certain embodiments, at least one of the annular injectors is an annular plasma injector further comprising:

[0017] a plasma electrode within the annular flow channel of the annular plasma injector;

[0018] an insulated feedthrough in an outer wall of the annular plasma injector, and a conductor conductively coupled to the plasma electrode, the conductor passing through the insulated feedthrough.

[0019] Within certain embodiments, the plasma electrode is ring-shaped.

[0020] In at least some embodiments, the annular injector closest to the opening at the bottom end of the cylindrical body is an annular plasma injector. While in certain embodiments, the annular injector furthest from the opening at the bottom end of the cylindrical body is an annular plasma injector.

[0021] In certain embodiments, the cylindrical body comprises an at least partially tapered cylinder. In some embodiments, the cylindrical body is in the shape of a truncated cone. In at least an embodiment, the cylindrical body comprises a funnel shape.

[0022] According to some embodiments, the assembly is modular such that the annular injector(s) and cylindrical body are releasably affixed to each other.

[0023] Within certain embodiments, the injection opening closest to the opening at the bottom end of the cylindrical body is a distance of at least one times the diameter of the cylindrical body away from the bottom of the cylindrical body.

[0024] In some embodiments, the annular injectors are welded to the cylindrical body.At least some embodiments further comprise a diffuser plate affixed within the cylindrical body between the at least one injection opening and the opening at the bottom end of the cylindrical body.

[0025] According to a second example aspect there is provided a chemical vapor processing reactor, such as an ALD, atomic layer deposition, or CVD, chemical vapor deposition, reactor, comprising an injection assembly as described herein.

[0026] According to a third example aspect there is provided a method of cleaning an injection assembly as described herein, the method comprising the step of introducing an etch gas; such as a chemical etching gas with plasma activation, to the topmost injection opening.

[0027] According to a fourth example aspect there is provided a method of atomic layer or chemical vapor deposition comprising multiple steps of deposition, each step comprising introducing at least one of: a plasma, etch gas, carrier gas or precursor into an annular injector of the injection assembly as described herein.

[0028] Different non-binding example aspects and embodiments have been illustrated in the foregoing. The embodiments in the foregoing are used merely to explain selected aspects or steps that may be utilized in different implementations. Some embodiments may be presented only with reference to certain example aspects. It should be appreciated that corresponding embodiments may apply to other example aspects as well.

[0029] BRIEF DESCRIPTION OF THE FIGURES

[0030] Some example embodiments will be described with reference to the accompanying figures, in which:

[0031] Figures 1a - 1c show schematical cross sections at a vertical center axis of gas injection assemblies according to certain embodiments;

[0032] Figures 2a and 2b show schematical cross sections at a vertical center axis of gas injection assemblies according to some embodiments;

[0033] Figures 3a and 3b show cross sections of the cylindrical body according to some embodiments;Figures 4a and 4b show cross sections of cylindrical bodies and annular injectors according to certain embodiments;

[0034] Figure 5 shows a schematical cross section at a vertical center axis of a gas injection assembly as installed in a reactor according to certain embodiments;

[0035] Figures 6a - 6d show schematical cross sections at a vertical center axis of gas injection assemblies according to at least some embodiments;

[0036] Figures 7a - 7g illustrate schematical cross sections of injection modules comprising electrodes according to certain embodiments;

[0037] Figures 8a and 8b show schematical cross sections of injection assemblies providing for angled injection according to at least some embodiments; and

[0038] Figures 9a and 9b show schematical cross sections of injection assemblies having modules of varying diameter according to at least some embodiments.

[0039] DETAILED DESCRIPTION

[0040] The basics of an atomic layer deposition, ALD, growth mechanism are known to a skilled person. ALD is a special chemical deposition method based on sequential introduction of at least two reactive precursor species to at least one substrate. A basic ALD deposition cycle consists of four sequential steps: pulse A, purge A, pulse B and purge B. Pulse A consists of a first precursor vapor and pulse B of another precursor vapor. Inactive gas and a vacuum pump are typically used for purging gaseous reaction by-products and the residual reactant molecules from the reaction space during purge A and purge B. A deposition sequence comprises at least one deposition cycle. Deposition cycles are repeated until the deposition sequence has produced a thin film or coating of desired thickness. Deposition cycles can also be either simpler or more complex. For example, the cycles can include three or more reactant vapor pulses separated by purging steps, or certain purge steps can be omitted. Or, as for plasma-assisted ALD, for example PEALD (plasma-enhanced atomic layer deposition), or for photon-assisted ALD, one or more of the deposition steps can be assisted by providing required additional energy for surface reactions through plasma or photon in-feed, respectively. Accordingly, the pulse and purge sequence may be different depending on each particular case. The deposition cycles forma timed deposition sequence that is controlled by at least one processor. Thin films grown by ALD are dense, pinhole free and have uniform thickness.

[0041] As for substrate processing steps, the at least one substrate is typically exposed to temporally separated precursor pulses in a reaction vessel (or chamber) to deposit material on the substrate surfaces by sequential self-limiting surface reactions. In the context of this application, the term ALD comprises all applicable ALD based techniques and any equivalent or closely related technologies, such as, for example the following ALD subtypes: MLD (Molecular Layer Deposition), plasma-assisted ALD, for example PEALD (Plasma Enhanced Atomic Layer Deposition) and photon-assisted or photon-enhanced Atomic Layer Deposition (known also as flash enhanced ALD or photo-ALD).

[0042] In ALD, at least one substrate is typically exposed to temporally separated precursor pulses in a reaction vessel to deposit material on the substrate surfaces by sequential selfsaturating surface reactions. In the context of this application, the term ALD comprises all applicable ALD based techniques and any equivalent or closely related technologies, such as, for example the following ALD sub-types: MLD (Molecular Layer Deposition) plasma-assisted ALD, for example PEALD (Plasma Enhanced Atomic Layer Deposition) and photon-enhanced Atomic Layer Deposition (known also as flash enhanced ALD).

[0043] The basics of chemical vapor deposition, CVD are known to a skilled person. In typical CVD, the wafer (substrate) is exposed to one or more volatile precursors, which react and / or decompose on the substrate surface to produce the desired deposit. Frequently, volatile byproducts are also produced, which are removed by gas flow through the reaction chamber. By varying experimental conditions, including substrate material, substrate temperature, and composition of the reaction gas mixture, total pressure gas flows, etc., materials with a wide range of physical, tribological, and chemical properties can be grown. CVD and related processes are employed in many thin film applications, including dielectrics, conductors, passivation layers, oxidation barriers, conductive oxides, tribological and corrosion-resistant coatings, heat-resistant coatings, and epitaxial layers for microelectronics.

[0044] An injection assembly for a chemical vapor reactor, such as an ALD, atomic layer deposition, or CVD, chemical vapor deposition reactor, is illustrated within Figure 1a. As illustrated, the injection assembly 100 comprises: a cylindrical body 110 comprising an opening 112 at a bottom end, the side of the cylindrical body comprising at least one injection opening 115. The injection assembly 100 further comprises at least one annular injector 130 comprising an annular flow channel 135 and an injection inlet 137 for receivingat least one of a: plasma, etch gas, carrier gas or precursor, the annular injector 130 being affixed around the cylindrical body 110 to envelop the injection opening 115 such that the injection opening 115, annular flow channel 135 and injection inlet 137 are in fluid connection.

[0045] Within at least some embodiments chemical vapor processing includes deposition or etching. In certain embodiments chemical vapor processing includes preclean prior to deposition or etching. In some embodiments chemical vapor processing includes atomic layer deposition, ALD.

[0046] As can be seen, the walls of the annular injector 130 serve to form the annular flow channel 135. In certain embodiments, the wall of the cylindrical body, also serves to form the annular flow channel. For example, in at least some embodiments, a portion of each annular injector forms a portion of the side of the cylindrical body. For example, as seen in Figure 1, the injector 130 and cylindrical body 110 may share a wall. In at least some embodiments the annular injector is affixed such that it is an integral part of the side or wall of the cylindrical body.

[0047] Figure 1a further illustrates how a flow channel is created from the injection inlet 137 to the annular flow channel 135 through the injection opening 115 into the inner volume of the cylindrical body 110.

[0048] In at least some embodiments, the annular injector is affixed around the cylindrical body such that the cylindrical body is within the ring-like shape formed by the annular injector. For example, as seen within Figure 1a. Figure 1b illustrates an example of certain embodiments wherein the annular injector is affixed at least partially within the cylindrical body. In some embodiments the annular injector is affixed at least partially within the cylindrical body such that the ring-like shape lies within and protrudes from the cylindrical body. In certain embodiments, for example the example embodiment of Figure 1c, the ringlike shape is subsumed by the cylindrical body. In some embodiments, the annular injector is affixed around the cylindrical body to encompass, surround and / or contain the injection opening such that the injection opening, annular flow channel and injection inlet are in fluid connection.

[0049] As also illustrated within Figure 1c, within at least some embodiments, the injection inlet comprises a hose connection 139. For example, within certain embodiments the hoseconnections are vacuum compatible. Certain embodiments employ compression fittings. At least some embodiments employ O-rings and certain embodiments comprise VCR fittings.

[0050] Also illustrated within Figure 1 is a substrate 170 to show a location of a substrate when the injection assembly is in use within a reactor system according to certain embodiments. Within certain embodiments the substrate is a wafer. In some embodiments the reactor system is a single wafer reactor system.

[0051] Figures 2a and 2b illustrate injection assemblies comprising a plurality of annular injectors and injection openings according to certain embodiments. As seen in Figure 2a, the injection assembly comprises a plurality of injection openings 215a, 215b, 215c and a plurality of annular injectors 230a, 230b and 230c, each annular injector being affixed around the cylindrical body 210 such that it envelops one of the injection openings 215a, 215b or 215c such that the annular flow channel 235a, 235b and 235c and injection inlet 237a, 237b and 237c of each injector is in fluid connection with one of the injection openings 215a, 215b or 215c. Injection assemblies according to certain embodiments may comprise two, three, four, five, six or more annular injectors. In at least some embodiments, each annular injector is affixed to the cylindrical body such that it covers a plurality of injection openings. For example, the annular injector may be sized so as to cover a plurality of injection openings or a plurality of sets of injection openings.

[0052] Within certain embodiments, the injection opening closest to the opening at the bottom end of the cylindrical body is a distance of at least one times the diameter of the cylindrical body away from the bottom of the cylindrical body. Within certain embodiments the injection opening closest to the opening at the bottom end of the cylindrical body is at least one diameter of the cylindrical tube away from the start of a taper of the cylindrical body leading to the opening. This may be provided, for example, by an injection module which itself comprises a cylindrical wall extended to an opening configured to be the opening at the bottom of the injection assembly.

[0053] Within certain embodiments having a plurality of annular injectors, there are dedicated lines for each annular injector. That is, the lines only serve to supply a single type of injection. Having several dedicated lines, such as several dedicated precursor lines, avoids crosscontamination.

[0054] As also illustrated within Figure 2a, within at least some embodiments, at least one of the annular injectors 230c is an annular plasma injector further comprising a plasma electrode245, within the annular flow channel 235c of the annular plasma injector; an insulated feedthrough 247 in an outer wall of the annular plasma injector, and a conductor 243 conductively coupled to the plasma electrode 245, the conductor passing through the insulated feedthrough 247. Within at least some embodiments, the plasma electrode is ringshaped. Within certain embodiments the annular plasma injector further comprises a cooling mechanism, such as, for example, water cooling. In embodiments comprising a plasma electrode, during operation, the electrode operates to filter out ions and only radicals are introduced into the inner volume of the cylindrical body via the injection opening.

[0055] Within at least some embodiments, the outer wall of the annular injector is a portion of the wall away from the cylindrical body. In some embodiments, the outer wall is the wall further from the cylindrical body, for example in embodiments wherein the annular injector is substantially a rectangular toroid. Within certain embodiments there is only a single annular injector, and it is an annular plasma injector.

[0056] Within at least some embodiments, the distance of the annular plasma injectors from the opening at the bottom of the cylindrical body, and thus from a substrate when the injector assembly is in use, provide for filtering out of ions in the plasma. In embodiments providing for filtering or removing of ions, there is lower plasma damage due to the lack of ions. Within at least some embodiments, filtering is provided for by affixing a perforated metal plate or mesh within the injection assembly. Such a perforated metal plate or mesh is affixed between an annular plasma injector and the opening at the bottom end of the cylindrical body within at least some embodiments. Within at least some embodiments the perforated metal plate or mesh is electrically grounded. While in some embodiments the perforated metal plate or mesh is connected to a de or ac source in order to control the electric field difference (voltage) between the perforated metal plate or mesh and a substrate.

[0057] Annular plasma injectors according to some embodiments are serviceable. For example, within certain embodiments the annular plasma injectors are modular such that they are releasably affixed to the cylindrical body and may be removed to service the annular plasma injector. Within at least some embodiments the outer wall of the plasma injector is removable so as to provide servicing of the electrode.

[0058] Within at least some embodiments, the assembly is modular such that the annular injector(s) and cylindrical body are releasably affixed to each other. Within certain modular embodiments there are interfaces between injectors such that they are modular. For example, within at least some embodiments the annular injectors further comprise flangesconfigured to allow for connection between flanges and / or the cylindrical body. At least some embodiments employ welded flanges. In certain embodiments the interface between injectors comprises a vacuum flange. For example, the vacuum flange may be configured to provide for a vacuum tight seal between the injection module and another body, such as another injection module or portion of a cylindrical body of an injection assembly. In at least some embodiments the interface is a quick release flange. For example, an ISO standard Quick Flange, QF, or Kleinflansch (KF) is employed in at least some embodiments. At least some embodiments employ CF flanges. Certain embodiments employ a flange having a chamfered back surface. Some embodiments employ a chamfered back surface configured to interface with an elastomeric O-ring, the flange being configured to interface with a circular clamp. Within certain embodiments the interface comprises a flange, centering ring and elastomeric O-ring.

[0059] In at least some embodiments, the annular injectors are welded to the cylindrical body. In certain embodiments, a portion of the annular injectors are welded to the cylindrical body. In at least some embodiments, the portion of annular injectors which are plasma annular injectors are not welded to the cylindrical body. Within certain embodiments the entire injector assembly is welded. In at least embodiments employing welds, leaks can be avoided without the need for O-rings or elastomer seals. By minimizing the use of seals, at least some embodiments avoid leaks and permeations of contaminants, such as oxygen. For example, providing for minimum oxygen incorporation allows for higher quality, ultralow oxygen content metal nitride films.

[0060] As seen in Figure 2a, within at least some embodiments, the annular injector 230c closest to the opening 212 at the bottom end of the cylindrical body 210 is an annular plasma injector. Embodiments having an annular plasma injector closest to the opening at the bottom end of the cylindrical body provide maximal radical flux on the substrate surface and minimal film growth upstream the flow channel. In such embodiments, deposition plasma gas can be injected closest to the substrate.

[0061] In certain embodiments, such as that of Figure 2b, the annular injector furthest from the opening at the bottom end of the cylindrical body is an annular plasma injector.

[0062] Figure 2b illustrates an embodiment of the injector assembly of Figure 2a wherein both the top and bottom annular injectors 230a and 230c are annular plasma injectors. In the embodiments of Figure 2b, each of injectors 230a and 230c further comprise a plasma electrode 245a or 245c within the respective annular flow channel 235a or 235c of theannular plasma injector; an insulated feedthrough 247a or 247c in an outer wall of the respective annular plasma injector, and a conductor 243a or 243c conductively coupled to the respective plasma electrode 245a or 245c, the conductor passing through the respective insulated feedthrough 247a or 247c. Within at least some embodiments, annular plasma injectors may be positioned at any point along the cylindrical body. That is, any one of the annular injectors may be an annular plasma injector comprising a plasma electrode as discussed here. It can be appreciated that the annular plasma injector(s) could be positioned at any point along the vertical axis of the cylindrical body.

[0063] At least some embodiments comprising annular plasma injectors provide for integrated Capacitively Couple Plasma (CCP). At least some embodiments provide for remote plasma -systems. Certain embodiments provide for Plasma Enhanced ALD (PEALD).

[0064] As seen in Figure 3a, within at least some embodiments there is a singular injection opening. Figure 3a shows both the side, or wall, 310a of the cylindrical body, but also the injection opening 312. This opening may be positioned relative to the injection inlet of the enveloping annular injector in a variety of ways as will be discussed later. In at least some embodiments the injections opening(s) are configured to ensure uniform flow.

[0065] Within certain embodiments the injection inlet and injection opening(s) are configured to ensure at least one of a uniform flow into an inner volume of the cylindrical body and turbulent mixing. In at least some embodiments, the flow injection angles relative to the tangent of the annular body are selected such that vortices or a vortex pattern will form in the annular channel and in the cylindrical flow channel increasing the effectiveness of mixing.

[0066] As shown by Figure 3b, within some embodiments, the injection opening comprises a plurality of holes spaced around the side of the cylindrical body. In certain embodiments, the plurality of holes are of varying diameters. Within at least some embodiments, the plurality of holes have the same diameter. Figure 3b shows both the side 310b of the cylindrical body, but also the injection opening 312a, 312b, 312c. As in Figure 3b, in certain embodiments the plurality of holes are evenly spaced around the side of the cylindrical body. In at least some embodiments the plurality of holes are aligned in a line around the side of the cylindrical body, for example such that no hole is closer to the opening at the body of the cylindrical body than any other hole.In certain embodiments, the injection opening comprises a slit. In at least some embodiments, the slit continues around the entire circumference of the cylindrical body such that the body is split into at least two segments.

[0067] Figures 4a and 4b illustrate annular injectors 430a and 430b of at least some embodiments. As seen, the annular injectors 430a and 430b each comprise injection inlets 437a and 437b respectively. Injection openings 412, 412a, 412b and 412c of the cylindrical body 410a and 410b are also shown. As seen within Figure 4b, in certain embodiments, the injection inlet 437b is not normal to annular injector 430b. In at least some embodiments, the injection inlet provides a flow path which is not normal to the annular flow channel of the annular injector. In some embodiments, the injection inlet is from 1 to 85 degrees from normal to the annular injector. In certain embodiments, the injection inlet is from 1 to 45 degrees from normal to the annular injector. In at least some embodiments the injection inlet is from 1 to 25 degrees from normal.

[0068] As seen in Figure 4a, the injection opening may be positioned opposite the injection inlet of the enveloping annular injector. The injection opening may also be positioned such that it is not directly in line with injection inlet. In at least some embodiments the injection opening and injection inlet may positioned at any position along the annular injector.

[0069] Figure 5 illustrates a chemical vapor reactor 501, such as an ALD, atomic layer deposition, or CVD, chemical vapor deposition reactor, the reactor 501 comprising an injection assembly 500 according to at least some embodiments. As shown, the injection assembly 500 comprises a plurality of annular injectors 530a, 530b, 530c, 530d, 530e, each annular injector being affixed around the cylindrical body 510 such that it envelops an individual injection opening such that the annular flow channel and injection inlet of each injector is in fluid connection with an individual injection opening. While five annular injectors are shown here, certain embodiments may comprise any number of annular injectors. Figure 5 further shows, optionally, that both the topmost 530a and bottommost 530e annular injectors are annular plasma injectors. In at least some embodiments, any number of the annular injectors are annular plasma injectors.

[0070] As seen within Figure 5, the reactor 501 is assembled such that the injection assembly 500 is releasably affixed or sealed to the remaining portions of the reactor 501 via a set of seals 565a and 565b. In certain embodiments, the seals may take the form of O-rings. The use of seals 565a and 565b according to some embodiments provides for thermal insulation if not isolation of the injection assembly from the remainder of the reactor.In at least some embodiments, the injection assembly 500 is connected to a reactor such that the topmost injector 530a is connected to one of a plasma, etch gas or carrier gas, the next three injectors 530b, 530c, 530d are connected to different precursors and the final injector 530e is connected to a plasma gas or carrier. However, the order and type of connections may vary and be in any order within certain embodiments.

[0071] According to certain embodiments, the injection assembly is held in place by the base 514 of the cylindrical body 512 being clamped to a body 561 of the reactor. In certain embodiments, the injection assembly 500 is clamped to the body 561 via a screw 563 which tightens a clamping plate 567 thus engaging the seals 565a, 565b. At least some reactors according to certain embodiments include vacuum generators to exhaust the reaction space formed by the inner volume of the injection assembly and the remainder of the reactor. Also illustrated within Figure 5 is a wafer or substrate 570 placed approximately relative to the injection assembly where it would be during a deposition cycle.

[0072] As also illustrated within Figure 5, within at least some embodiments, the injection assembly 500 comprises a top inlet 555. In certain embodiments the top inlet is for the addition of remote plasma, precursor and / or etch gas. The top inlet also provides for the option to purge the injection assembly and / or reactor with a carrier gas from the top. In at least some embodiment, the top inlet 555 allows for an inert gas to be introduced at the top inlet 555 such that it pushes plasma generated active species towards the wafer or substrate 570, and to accelerate the purging. In certain embodiments the injection assembly comprises an inlet configured to purge the injection assembly, such a purging inlet may be placed, for example: substantially opposite to a foreline or exhaust gas line, at the opposite end of the injection assembly from where a deposition target would be located during deposition, substantially opposite the opening at the bottom of the injection assembly.

[0073] Further illustrated within Figure 5 are the radio frequency, RF, generators 569a and 569b. As shown, the RF generators are conductively connected to the electrodes 545a and 545b of plasma injectors 530a and 540e. As seen, connections to the electrodes is provided through insulators 547a and 547b. Within certain embodiments this connection through the insulators, or insulated electrical feedthroughs, is the only support of the electrodes within the injectors. In some embodiments the electrodes are supported via various insulated supporting means arranged within the injector body. Once again, while the RF generators are illustrated at the top and bottom annular injectors, they may be located at any injector comprising a plasma electrode.Within at least some embodiments direct current, DC, sources are connected to the plasma injectors to provide for DC generated plasma. Many embodiments provide for plasma generation with either a DC or RF source.

[0074] As can be seen within Figure 5, within at least some embodiments, the area of the injection assembly comprising injectors is referred to as an electrode and / or a source zone 557.

[0075] In at least some embodiments the injection assembly is configured to be connected to a ground potential when installed into a reactor. For example, at least some embodiments comprise a conductive connector conductively affixed to the cylindrical body of the injector assembly.

[0076] At least some reactors according to certain embodiments do not require an outside vacuum chamber. Due to the sealing provided by the construction of the injection assembly and interface with the reactor, the outer surface of the injection assembly may be kept at atmospheric pressure. This allows for easier control of the temperature of the injection assembly. At least some embodiments further comprising a heating arrangement affixed around the outer surface of the injection assembly.

[0077] Figures 6a - 6d illustrate injection assemblies 600a - 600d according to certain embodiments. The injection assemblies 600a - 600d are shown installed within reactors 601a - 601 d. As illustrated, within at least some embodiments, the cylindrical body comprises a tapered cylinder. This may be embodied within only a portion of the cylindrical body as shown in figures 6a - 6c. As shown, the taper may be either expanding the cylindrical body or contracting the cylindrical body. Within some embodiments, the taper is comprised only within the portion of the cylindrical body not having annular injectors. For example, the taper may be comprised in the bottom half or third of the cylindrical body. As per Figure 6a, the taper may be such that the cylindrical body expands in width or radius until the opening at the bottom of the cylindrical body. For example, such that the diameter matches or is slightly larger than the target substrate or wafer. As per Figure 6b within certain embodiments, the taper is a narrowing taper. In certain embodiments the taper narrows to a diameter less than the that of the substrate, wafer or deposition target.

[0078] In at least some embodiments the cylindrical body is shaped, and injector constructed, such that there are no edges between the bottommost injector and the opening at the bottom of the cylindrical body, that is the opening in the cylindrical body configured to face the substrate for deposition when the injection assembly is installed in a reactor.Within at least some embodiments, the entire cylindrical body is tapered. Within certain embodiments, the cylindrical body comprises multiple tapers. In some embodiments, the cylindrical body is a cone. For example, within certain embodiments, the cylindrical body is in the shape of a truncated cone as seen in Figure 6d.

[0079] As seen in Figure 6a and 6d, at least some embodiments further comprise a diffuser plate 617 affixed within the cylindrical body between the at least one injection opening and the opening at the bottom end of the cylindrical body. In certain embodiments the diffuser plate is between the annular injector closest the opening at the bottom end of the cylindrical body and the injection opening closest the opening at the bottom end of the cylindrical body. In certain embodiments, there are a plurality of diffuser plates arranged between different injectors. In at least some embodiments there are diffuser plates arranged between each injector or between the electrode zone and the wafer.

[0080] As illustrated in Figures 6a - 6d the opening at the bottom end of the cylindrical body may take on a variety of shapes and sizes. In at least some embodiments, for example as shown in Figure 6b, the opening is smaller than the target substrate. In at least some embodiments the opening is sized to cover the entire target substrate.

[0081] Annular plasma injectors 730a - 730g, further comprising at least one plasma electrode affixed to the annular plasma injector according to certain embodiments are shown in Figures 7a - 7g. As seen in Figures 7a and 7d, the electrodes 745a, 745d of plasma injectors according to certain embodiments are configured to be connected to a source 769a, 769d, for example a DC or RF source, via insulated feedthroughs 747a, 747d. As further illustrated, plasma injectors according to the illustrated embodiments each comprise an annular flow channel 735a - 735d, plasma electrode 745a - 745d, injection opening 715a - 715d, injection inlets 737a, 737b, 737b', 737c, 737c’, 737d, and a cylindrical body 710.

[0082] While the injectors of Figures 7a - 7c are illustrated relative to a substrate 770 as if they comprised the entirety of the injection assembly, it will be appreciated that the injectors may be included with other injectors in an injection assembly as discussed here. Similarly, the injectors of Figures 7a - 7d may replace the plasma injectors of any other embodiment.

[0083] Within certain embodiments as illustrated by Figures 7a - 7b, the electrodes 745a, 745b form capacitively coupled plasma, CCP. Plasma generated by such electrodes is more homogeneous as the electrodes are equidistant from the wall of the injector module. Also,within the annular flow channels, the flow of plasma gases is more uniform. Within certain embodiments, as illustrated within Figures 7b and 7c, there may be two injection inlets 737b, 737b’, 737c, 737c’. For example, within certain embodiments the injection inlets are arranged on opposing sides of the injector. Within Figure 7b, suspension of the electrode may be accomplished as in previous embodiments, for example, via the insulating feedthrough not illustrated within Figure 7b as the cross section does not bisect said feedthrough.

[0084] As seen within Figure 7c, within at least some embodiments the cross-section of the electrode is non-uniform. Within at least some embodiments the cross-section of the electrode comprises a shape having at least one corner or sharp edge. As seen, in certain embodiments the cross-section is polygonal, for example, in the shape of a pentagon. The provision of such corners or sharp edges provides for better plasma generation and ensures more homogenous plasma . Further, the corners or sharp edges provide for easier ignition of plasma even over short durations. For example, within certain embodiments, the corners or sharper edges of the electrode allow for ignition of plasma even over pulses of less than half a second.

[0085] Figure 7d illustrates a plasma injector according to at least some embodiments wherein the electrode comprises at least a portion of an inner wall of the annular injector. For example, as seen in Figure 7d, the electrode 745d according to certain embodiments forms a portion of a wall defining the annular flow channel 735d. In at least some embodiments the electrode 745d is separated from an outer wall 731 d of the injector 730d by a layer of electrically insulating material 749d. In at least some embodiments this electrically insulating material 749d is the same material used for the insulated feedthrough 747d. In certain embodiments the insulated feedthrough 747d and insulating material layer 749d are a continuous layer of electrically insulating material.

[0086] In at least some embodiments, the injector comprises a further insulated feedthrough to provide cooling to the electrode. For example, the feedthrough may be configured to provide a fluid flow around and / or through at least a portion of the electrode. In at least some embodiments the further insulated feedthrough is comprised within another insulated feedthrough to form a coaxial feedthrough.

[0087] As also seen in Figure 7d, within certain embodiments the electrode 745d is conductively connected to a conductor which passes through an insulated feedthrough 747d to a connection for source 769d, for example an RF or DC source. The conductor is insulatedfrom an outer wall 731 d of the injector 730d via the feedthrough and the insulating material 749d. The electrode 745d is insulated from the cylindrical body by electrode insulating 747d’. In this fashion, the electrode 745d may be at a different electrical potential than the outer wall of the injector 731 d which is conductively connected to the cylindrical body.

[0088] In at least some embodiments the outer wall 731 d is conductively isolated from the cylindrical body. In certain embodiments, both the outer wall 731d and the electrode 745d are insulated from the cylindrical body.

[0089] Figures 7d - 7g illustrate annular plasma injectors 730d - 740f comprising electrodes having an annular shape, or ring electrodes. As seen, just electrodes may take on a variety of shapes and in some embodiments, may form a portion of the annular flow channel.

[0090] Figures 7e and 7f illustrate the manner in which an electric potential can be conducted to electrodes of annular plasma injectors according to certain embodiments. In at least some embodiments, a first conductive connection is provided to a first electrode within the annular flow channel as seen in Figure 7e. As shown, this connection may be provided via a conductor passing through an insulated feedthrough. As per Figure 7f, within certain embodiments, alternatively, or in addition, to the connection of Figure 7e, a conductive connection is provided to a ring electrode surrounding the annular flow channel via an insulated feedthrough.

[0091] Figures 7e and 7f illustrate annular plasma injectors 730e and 730f, further comprising a further plasma electrode. That is, annular plasma injectors according to at least certain embodiments comprise two electrodes. As can be seen, plasma electrodes according to certain embodiments have an annular shape. In at least some embodiments, a plasma electrode forms at least a portion of the annular flow channel, or wall of the annular flow channel.

[0092] Within at least some embodiments, the body of the injector comprises at least one of: Ti, Ni, stainless steel, Al or an alloy comprising one of the mentioned materials. In certain embodiments, coatings of the injectors and / or injection assemblies, electrodes or plasma units can be done using at least one of: Ti, Ni, Al, Mo, Co, Cu, V, Ag, Ru, Au, and oxides of the above listed elements and oxides of elements such as Si, Zn, Zr, Sn, Hf, Nb, Ta. Within at least some embodiments the electrodes comprise at least one of: W, Ti, Ni, Cu, Al, and stainless steel.Figures 8a and 8b illustrate injection assemblies 800a, 800b according to at least some embodiments of the present invention. The injection assemblies 800a, 800b are installed into reactors 801a, 801b. The assemblies may be modular as described elsewhere herein. Within at least some embodiments, such as those illustrated within Figures 8a and 8b, the injectors 830a - 830c are arranged such that injection is performed at an angle which is not normal to the wall of the cylindrical body. Within at least some embodiments this angled injection may be accomplished by providing an injection path 817 between the annular flow channel 835 and injection opening 815. This injection path may be provided by, for example, a plurality of pipes leading to a plurality of injection openings. The injection path may also be provided by a further annular shape disposed between the annular flow channel 835 and injection opening 815. For example, the injection path may form a ring around the cylindrical body. Injection may be performed at a positive angle, such that injection is angled towards the opening at the bottom of the cylindrical body; or at a negative angle, such that the injection is angled away from the opening at the bottom of the cylindrical body.

[0093] As also seen in Figure 8a and 8b, according to certain embodiments, the shape of the injectors is such that they have a skewed annular channel. In at least some embodiments the angle of skey of the annular channel matches the angle of injection.

[0094] Further illustrated within Figures 8a and 8b is that, in at least some embodiments, the number of injectors is adjusted based on the intended usage. Any number of injectors may be employed, while three are illustrated here for the sake of clear illustration.

[0095] As seen in Figures 9a and 9b, at least some embodiments comprise injection assemblies having a varying diameter. As illustrated in Figure 9a, within certain embodiments the diameter of the cylindrical body varies such that there are at least two distinct diameters. Within at least some embodiments the cylindrical body has two distinct diameters, within certain embodiments there are only two distinct diameters. In certain embodiments the cylindrical body varies in diameter such that at each injector, the cylindrical body is of a different diameter, as seen in Figure 10b.

[0096] According to a third example aspect there is provided a method of cleaning an injection assembly as described herein, the method comprising the step of introducing an etching fluid, such as a thermal etching or plasma etching fluid. In at least some embodiments thermal etching using gas and / or liquid phase etching is employed. In certain embodiments a plasma etch gas is introduced to the topmost injection opening. Such a method of cleaning may be employed in-situ, that is, when the injection assembly is installed for use. Certainembodiments are configured to provide cleaning via a topmost, that is furthest from the bottom opening, annular injector. Such topmost injectors may be used to activate etch and clean out the injection assembly, for example, in a periodic fashion.

[0097] Within at least some methods of cleaning, the injection assembly is sand blasted in order to clean the assembly. Such sand blasting may be performed in lieu of or in addition to the plasma etch cleaning as discussed herein. In certain methods of cleaning, the injection assembly is detached from the reactor, or uninstalled and mechanically cleaned. In at least some methods the injection assembly is cleaning by mechanically abrasive methods or chemical methods. Cleaning according to certain embodiments may be performed on when the injection assembly is disassembled into parts. For example, within at least some embodiments, modules of the injection assembly are disconnected from each other prior to cleaning.

[0098] According to a fourth example aspect there is provided a method of atomic layer or chemical vapor processing, such as deposition comprising multiple steps of deposition, or etching, also potentially comprising multiple steps, or pre cleaning. Each step comprising introducing at least one of: a plasma, etch gas, carrier gas or precursor into an annular injector of the injection assembly as described herein.

[0099] At least some embodiments provide for the ability to be run in thermal mode, or plasma mode, or a combined thermal + plasma in one process step. At least some embodiments provide for thermal ALD. While certain embodiments provide for a pre cleaning step or etching step.

[0100] At least some annular injectors according to certain embodiments are toroidal. Toroids as discussed herein include, but are not limited to, round toroids, square toroids, rectangular toroids, and elliptical toroids. At least some toroidal objects as discussed herein include toroidal polyhedrons. Certain toroidal objects are irregular toroids such that they do not have a consistent cross section. At least some toroidal objects are annular.

[0101] According to an example aspect there is provided a method for treating a substrate, the method comprising the steps of: placing the substrate in a reactor comprising an injection assembly according embodiments described herein, treating the substrate by introducing at least one of a plasma, etch gas, carrier gas or precursor via the injection inlet of the at least one annular injector. Within at least some embodiments, the method further comprises the step of purging the reactor after the step of treating the substrate. In certainembodiments, the method comprises repeating the treating and purging steps sequentially until a desired treatment of the substrate is achieved. In at least some embodiments, the injection assembly comprises a plurality of annular injectors each connected to an individual input and the sequentially treatment comprises introducing at least one of a plasma, etch gas, carrier gas or precursor through different injection inlets of the plurality of annular injectors during different treatment steps. In certain embodiments, the injection assembly comprises at least one annular plasma injector and the treating of the substrate comprises multiple steps, wherein a portion of the steps are conducted in a plasma mode and a portion of the steps are conducted in a thermal mode.

[0102] Without limiting the scope and interpretation of the patent claims, certain technical effects of one or more of the example embodiments disclosed herein are listed in the following. The annular injector provides for gas mixing at the injection point and the injection openings provide for faster precursor delivery and quick purging. In embodiments having a plurality of injectors, many precursors can be brought to the injector through separated, individual flow channels. These separate flow channels provide for easier adjustment of flow rates for each gas injection channel and allows for optimization of mixtures and purges. There is minimal dead volume, thus streamlining flow paths and providing for faster purging. The separate flow paths provided for by embodiments having a plurality of injectors prevents mixing of precursors before the deposition target and thus avoid deposits in the system itself. At least some embodiments provide for a closed structure from the substrate normal direction thus avoiding cold spots that the substrate emissive heat radiation would sink, forming colder spots on the substrate.

[0103] In further embodiments, the injection assembly may be applied to other deposition technologies, such as Physical Vapor Deposition (PVD) and Plasma-Enhanced Chemical Vapor Deposition (PECVD), etching, plasma etching, Plasma Atomic Layer Etching, atomic layer etching and other chemical vapor processes.

[0104] In certain embodiments, the injection assembly is for use in an atomic layer etching (ALE) apparatus. For example, within at least some embodiments, the annular injectors provide for the introduction of at least one of a plasma and thermal etch in a process step within an ALE apparatus or method.

[0105] Various embodiments have been presented. It should be appreciated that in this document, words comprise, include, and contain are each used as open-ended expressions with no intended exclusivity.The foregoing description has provided by way of non-limiting examples of particular implementations and embodiments a full and informative description of the best mode presently contemplated by the inventors for carrying out the invention. It is however clear to a person skilled in the art that the invention is not restricted to details of the embodiments presented in the foregoing, but that it can be implemented in other embodiments using equivalent means or in different combinations of embodiments without deviating from the characteristics of the invention.

[0106] Furthermore, some of the features of the afore-disclosed example embodiments may be used to advantage without the corresponding use of other features. As such, the foregoing description shall be considered as merely illustrative of the principles of the present invention, and not in limitation thereof. Hence, the scope of the invention is only restricted by the appended patent claims.

Claims

CLAIMS1. An injection assembly for a chemical vapor reactor, such as an ALD, atomic layer deposition, CVD, chemical vapor deposition, or ALE, atomic layer etching, reactor; the injection assembly comprising:a cylindrical body comprising an opening at a bottom end, the side of the cylindrical body comprising at least one injection opening, andat least one annular injector comprising an annular flow channel and an injection inlet for receiving at least one of a: plasma, etch gas, carrier gas or precursor, the annular injector being affixed around, partially within or completely within the cylindrical body to envelop the injection opening such that the injection opening, annular flow channel and injection inlet are in fluid connection.

2. The injection assembly of claim 1 , wherein the injection opening comprises:one or more holes spaced around the wall of the cylindrical body, and / ora slit.

3. The injection assembly of claim 1 or 2, wherein the injection opening comprises is configured such that the plasma, etch gas, carrier gas or precursor enters the reactor at an angle to enable vertical delivery.

4. The injection assembly of any preceding claim, comprising a plurality of injection openings and a plurality of annular injectors, each annular injector being affixed around, partially within or completely within the cylindrical body such that it envelops an individual injection opening such that the annular flow channel and injection inlet of each injector is in fluid connection with an individual injection opening.

5. The injection assembly of any preceding claim, wherein at least one of the annular injectors is an annular plasma injector further comprising: a plasma electrode affixed to the annular plasma injector.

6. The injection assembly of claim 5, further comprising at least one insulated feedthrough in an outer wall of the annular plasma injector, and at least one conductor conductively coupled to at least one of the plasma electrodes, the conductor passing through the insulated feedthrough.

7. The injection assembly of any of claims 5 or 6, wherein an outer wall of the annular plasma injector comprises a non-conductive material, such as ceramic.

8. The injection assembly of any of claims 5 - 7, wherein at least one of the electrodes forms at least a portion of the wall of the annular channel of the annular plasma injector.

9. The injection assembly of claim 8, wherein the at least one of the electrodes forming at least a portion of the wall of the annular channel surrounds the annular channel.

10. The injection assembly of any of claims 5-9, wherein at least one of the electrodes has an annular shape.

11. The injection assembly of any of claims 6- 10, wherein at least one of the electrodes is suspended within the annular flow channel of the annular plasma injector via the conductor passing through the insulated feedthrough.

12. The injection assembly of any of claims 5 - 12, wherein the annular injector closest to the opening at the bottom end of the cylindrical body is an annular plasma injector.

13. The injection assembly of any preceding claim, wherein the cylindrical body comprises a tapered cylinder.

14. The injection assembly of any preceding claim, wherein the injection opening closest to the opening at the bottom end of the cylindrical body is a distance of at least one times the diameter of the cylindrical body away from the opening.

15. The injection assembly of any preceding claim, wherein the annular injectors are welded to the cylindrical body.

16. The injection assembly of any preceding claim, further comprising a diffuser plate affixed within the cylindrical body between the at least one injection opening and the opening at the bottom end of the cylindrical body.

17. A chemical vapor reactor; such as an ALD, atomic layer deposition, or CVD, chemical vapor deposition, reactor; comprising the injection assembly of any preceding claim.

18. A method of in-situ cleaning the injection assembly of any one of claims 1 - 16 comprising the step of introducing a plasma etch gas to the topmost injection opening.

19. A method for treating a substrate, the method comprising the steps of:placing the substrate in a reactor comprising an injection assembly according to any one of claims 1 - 16,treating the substrate by introducing at least one of a plasma, etch gas, carrier gas or precursor via the injection inlet of the at least one annular injector.

20. The method of claim 19, wherein the injection assembly comprises at least one annular plasma injector and the treating of the substrate comprises multiple steps, wherein a portion of the steps are conducted in a plasma mode and a portion of the steps are conducted in a thermal mode.

Images