JP2009529223A - Small volume symmetrical flow single wafer ALD system - Google Patents

Abstract

  The ALD reaction chamber includes a vertically movable heater susceptor with an annular attached flooring conduit on its outer periphery, which when the heater susceptor is in its process position, above the wafer and against the bottom of the flooring. The edge is provided with an external surface separating the external space of the reactor below. When the susceptor is in the process position, the ring and conduit together form a tongue-in-groove (TIG) structure where the outer edge of the flooring is close to the annular ring attached to the reaction chamber Hd. In some cases, the TIG design can be provided with a stepped shape (SC) to limit the diffusion back flow of the downstream gas to the external space of the reactor.

Description

RELATED APPLICATION This application is a regular application of US Provisional Patent Application No. 60 / 820,042 filed on July 21, 2006, and claims priority thereto, November 22, 2005. Claiming priority to German patent application No. 105005636326.6 filed on September 13, 2004, and in addition to the regular application of US Provisional Patent Application No. 60 / 609,598 filed on September 13, 2004. Related to U.S. Patent Application No. 11 / 224,767 filed on September 12, 2005, claiming priority thereto, which is incorporated by reference. Each is assigned to the co-owner of the present invention and is incorporated herein by reference.

  The present invention minimizes reaction space volume and at the same time improves ALD cycle time by maintaining gas flow symmetry associated with off-axis wafer transport slot valves and / or off-axis downstream pumping conduits. The present invention relates to a volume symmetric flow atomic layer deposition (ALD) apparatus.

  ALD reactors can have various design structures. The structure of a conventional single wafer ALD reactor includes a cross-flow design, where sequential chemical precursor exposure (pulse) and implantation gas removal (purge) cause the wafer surface to be approximately horizontal. It flows across and is likewise sent out horizontally. Wafer transport can be performed in the same horizontal plane perpendicular to the gas flow direction. The term “traveling wave” has been used to describe the movement of time-dependent precursor pulses from the injection orifice to the pump orifice. For example, refer to prior art documents (see Non-Patent Document 1).

  In the case of so-called “pure” ALD processes, the first precursor is completely removed from the reaction space before the second precursor is introduced. For example, refer to prior art documents (see Non-Patent Document 2). However, when the wafer is scaled to a larger size, for example 300 mm or 450 mm, and when the cycle time is reduced to the lower limit, undesirable parasitic chemical vapor deposition (CVD) occurs in the direction of the traveling wave at the edge of the wafer. To occur. Parasitic CVD results from an undesirable chemical reaction due to the coexistence of residual precursors in time and space simultaneously at the tail of the dispersed first precursor and at the beginning of the second precursor. In order to avoid this parasitic CVD, precursor removal is used between pulses. Often a long removal time is required. In the case of a horizontal single wafer structure, to avoid this parasitic CVD, the concentration of the trailing edge of the first precursor pulse is up to any number of trace bells, for example, less than about 1% of the peak value of the first precursor. Must be reduced. For example, refer to prior art documents (see Patent Document 1).

  Since ALD is a self-regulating process, if sufficient time is utilized for the precursor removal period, commonly referred to as the “purge period”, no significant CVD will occur, so it is symmetric with the precursor flow direction. It can be said that sex is not a problem. However, flow symmetry becomes important when seeking high deposition rates (thickness / unit time or low cycle time) and reducing the purge time to the shortest possible time for values in commercial production.

  An alternative single wafer design utilizes a precursor gas injected from an axial and axisymmetric vertical gas supply module (GDM) (e.g., using an axial orifice or showerhead), where the distributed tail is highly inverted. As advantageous in the case of diffusion, it is constrained to overlap by the radius of the wafer (half the diameter), allowing faster delivery of unutilized and by-product gases (omnidirectional delivery) and removal. It becomes possible.

  Many commercial single wafer ALD reactors today utilize vertical precursor injection followed by a vertical feed followed by a radial flow. FIG. 1 illustrates such an ALD reactor system 10 in which two precursors (A, B) are injected vertically into the reaction chamber 14 via valves 12a, 12b. Gas is extracted from the reaction chamber 14 by the pump 16. As shown in the illustration, the gas in the reaction chamber 14 initially flows vertically from, for example, a showerhead or other implanter 18 disposed axisymmetrically above a wafer 20 that is typically supported by a susceptor 22. Then, it flows radially outward from the center of the wafer 20 to its edge. Next, the gas is sent out from the reaction chamber 14 so as to make a vertical flow, and the combined delivery of the radius and the vertical flow is performed. Ideally, this configuration would make the flow at the wafer edge symmetrical.

As illustrated in FIG. 2, in the case of a commercially available single wafer system, the wafer to be processed is sent to the reactor by the robot central handler 24. These wafer transport mechanisms are generally also used in CVD equipment useful for the silicon chip manufacturing industry. Wafer 26 is introduced through a rectangular slot valve 28 located at a specific azimuth and range (θ ₁ and Δθ ₁ ), typically on the radius or outer surface of reaction chamber 14 proximate to the reactor wall. . The slot valve 28 and the rectangular passage to the reaction chamber 14 break the symmetry of the radial gas flow schematically shown in the explanatory diagram.

Further, a downstream discharge pump 16 is generally provided in the azimuth and range θ ₂ and Δθ ₂ . Here, θ ₂ is generally not necessarily the same as θ ₁ . This configuration is compatible with on-axis mechanical drive support hardware that allows vertical movement of the susceptor, but at the same time these asymmetries can form recirculation pockets, stagnation zones and / or discharge azimuth misalignments. Uniformity can be formed. For example, if residual precursor from the first precursor stream is exhausted or swept away from the wafer with non-uniform azimuthal flow, the parasitic CVD is asymmetrical or non-uniform toward one azimuthal direction of the wafer. There are additional mechanisms that occur uniformly. In this case, the occurrence of parasitic CVD occurs asymmetrically and early in a particular azimuthal direction or direction due to recirculation, stagnation and / or evacuation effects.

  The desirability of a small reaction space volume (the space above the wafer between the wafer and the precursor injection component (eg showerhead)) is known in the art. For example, refer to prior art documents (see Non-Patent Document 3). To shorten precursor removal time, residence time (PV / F, where P is pressure, V is the volume of the reaction space, and F is the flow rate through the reaction space), and therefore to shorten the ALD cycle time Should minimize the volume of ALD reaction space. In the case of a vertically movable susceptor design (see, for example, the prior art document (see Patent Document 2)), the distance between the wafer surface and the gas supply orifice (shower head) of the reactor lid depends on the flow rate and the residence. It can be optimized for time uniformity, i.e. the volume of the reaction space can be minimized within the limits of locally uniform exposure. Furthermore, the reaction space can include an annular region between the susceptor edge forming the parasitic reaction space volume and the upper inner wall of the reactor.

US Pat. No. 6,015,590 US Pat. No. 5,855,675 (assigned to Doering et al., Assigned to the assignee of the present invention and incorporated herein by reference) T.A. See Suntola, edited by Huerle, “Atomic Layer Epitaxy”, Handbook of Crystal Growth, Vol. 3, 1994, Chapter 14, p. S. M.M. Bedair, “Atomic layer epitaxy deposition processes”, J. Am. Vac. Sci. Tech. B12 (1), 1994, January issue, p.179 and below M.M. Ritala and M.M. By Leskela, H.C. See Nalwa, “Atomic Layer Deposition”, Handbook of Thin Film Materials, Volume 1, 2002, Chapter 2, p.103 and below.

  Flow symmetry due to the azimuthal arrangement of the wafer slot valve and wafer path is vertical because the wafer is positioned above the wafer slot valve when the wafer and its heater / susceptor are in process position. Although largely restored by using a movable susceptor / heater, this approach was nevertheless limited with respect to fine tuning of the symmetric flow. For example, when the susceptor was in its process position, the downstream gas also formed a stagnation region and vortex in the pocket associated with the wafer slot valve below the wafer surface. Therefore, there is a need for a reactor design that minimizes reaction space volume, improves symmetric flow, and at the same time maintains the ability to interface with conventional wafer (slot) transport mechanisms. In accordance with the present invention, a solution to these requirements is provided, resulting in a small limited volume resulting in a symmetric flow, providing a high throughput, high performance (HP) single wafer reactor.

  In one embodiment of the present invention, the reaction chamber apparatus includes a vertically movable heater susceptor that is connected to an annular accessory flooring that functions as a gas conduit, with the susceptor in the process (high) position. At the end, the floor outlet port extends below the bottom of the wafer transport slot valve.

  In accordance with another embodiment of the present invention, a reaction chamber apparatus is provided that includes a heater susceptor, the outer periphery of which is connected to an annular attached flooring conduit, the conduit being connected to the process of the heater susceptor relative to its loading position. When in the (high) position, the edge is provided with an external surface that separates the external space of the reaction chamber above and below the floor of the flooring from the limited reaction space.

  In yet another embodiment, the present invention provides a reaction chamber apparatus comprising a heater susceptor, the outer periphery of which is connected to an annular attached flooring conduit, wherein the conduit is connected to the process of the heater susceptor relative to its loading position. When in the (high) position, the edge has an external surface that separates the external space of the reaction chamber above the wafer from the limited reaction space, and the outer edge is adjacent to an annular ring attached to the lid of the reaction chamber. Both the ring and the conduit outer member serve as a tongue-in-groove (TIG) structure. In some cases, the TIG design can be provided with a stepped shape (SC) to limit the diffusion back flow of the downstream gas to the external space of the reactor.

  According to another embodiment of the present invention, there is provided a reaction chamber apparatus comprising a vertically movable susceptor (VMS) for a charged (low) position, the susceptor having an annular attached flooring (AFR) (or deep) on its outer periphery. Connected to a flooring (DFR) conduit, the annular AFR conduit delivers the exhaust reactant gas to a downstream pump orifice that is off-axis relative to the center of the reaction chamber axis. In some cases, it is possible to place a downstream baffle between the lower orifice of the annular AFR and the downstream pump to produce a symmetric gas flow at the wafer edge of the upstream wafer surface.

  According to yet another embodiment of the present invention, there is provided a TIG chamber structure as described above comprising a pump connected to remove gas flow from the reaction space, an AFR conduit, and a lower chamber leading to the pump. A gas injection orifice is provided that allows the reaction space and the AFR conduit to be bypassed so that the gas injected into the orifice flows into the flow down to the pump below the output orifice of the AFR. Therefore, this orifice allows gas to be directly injected into the pumping conduit that leads directly to the pump input periodically during ALD cycling without the need for additional restriction between the AFR output orifice and the pump input orifice. Become.

  In yet another embodiment, the ALD apparatus includes a plurality of process modules, each process module comprising one or more reaction chambers, each reaction chamber having a position between the process position and the loading / unloading position. The substrate holder is movable in the vertical direction, and when each of the substrate holders reaches the process position in the respective reaction chamber, an exhaust port is formed in the respective reaction chamber. Oriented, the ports are formed by the outer peripheral walls of the respective reaction chambers and the edge surfaces of the respective substrate holders. The wall surface of the exhaust port channel is attached to the substrate holder and is movable therewith. The upper segment of the outer wall segment of the exhaust port channel desirably fits within the ring groove, which fits around a circular shield that itself fits around the air distributor of each individual reaction chamber.

  Further embodiments, features and advantages of the present invention are discussed below.

  For purposes of illustration and not limitation, the present invention is illustrated in the figures of the accompanying drawings.

  Described herein is a small volume symmetric flow (SVSF) apparatus defined for a minimum ALD reaction volume that produces symmetric flow with minimal chemical transport to the reactor walls. This description includes the design of the reactor and its functionality, as well as a small volume with respect to the reaction space, a general design to separate the reaction space from the reactor wall without recirculation, and gas expansion below the wafer surface. Time phase multi-level choke downstream pump structure with all-round design to minimize volume and achieve flow symmetry in the case of off-axis pumping conduit with maintainability and assembly characteristics Includes discussion on the combined effects of

  In one embodiment of the present invention, the reaction chamber apparatus includes a vertically movable heater susceptor that is connected to an annular attached flooring that functions as a gas conduit and the susceptor is in the process (high) position. At the end, the floor outlet port extends below the bottom of the wafer transport slot valve.

  In accordance with another embodiment of the present invention, a reaction chamber apparatus is provided that includes a heater susceptor, the outer periphery of which is connected to an annular attached flooring conduit, the conduit having a heater susceptor relative to its loading position. When in the process (high) position, it has an outer surface at its edge that separates the reactor outer space above and below the floor from the floor of the flooring from the limited reaction space.

  In yet another embodiment, the present invention provides a reaction chamber apparatus that includes a heater susceptor, the outer periphery of which is connected to an annular attached flooring conduit, the conduit being connected to the loading position of the heater susceptor. When in its process (high) position, it has an outer surface at its edge that separates the outer space of the reactor above the wafer from the limited reaction space, and the outer edge is a ring attached to the lid of the reaction chamber Located in close proximity to the ring, the ring and conduit outer member together act as a tongue-in-groove (TIG) structure. In some cases, the TIG design can be provided with a stepped shape (SC) to limit the diffusion back flow of the downstream gas to the external space of the reactor.

  In the case of the embodiment of the present invention, it is important that the tongue member and the groove member are designed and operated so that these members do not come into physical contact with each other. The contact member would be a particle source mechanism, possibly causing contact sticking between metals (metal bonding in a vacuum), making it difficult to retract the heater susceptor. Furthermore, the contact design makes it very difficult to maintain mechanical stability. For these reasons, a “proximity” or “diffusion-sealed” TIG mechanism was designed and operated.

  According to another embodiment of the present invention, there is provided a reaction chamber apparatus with a vertically movable susceptor (VMS) for its charging (low) position, the susceptor having an annular attached flooring (AFR) at its outer periphery. (Or deep flooring (DFR)) connected to a conduit that delivers the exhaust reactant gas to a downstream pump orifice that is off-axis relative to the center of the reaction chamber axis. In some cases, it is possible to place a downstream baffle between the lower orifice of the annular AFR and the downstream pump to produce a symmetric gas flow at the wafer edge of the upstream wafer surface.

  In accordance with yet another embodiment of the present invention, there is provided a TIG chamber structure as described above comprising a pump connected to remove gas flow from the reaction space, an AFR conduit, and a lower chamber leading to the pump. A gas injection orifice is provided that allows the reaction space and the AFR conduit to be bypassed so that the gas injected into the orifice flows into the flow down to the pump below the output orifice of the AFR. Thus, this orifice allows gas to be directly injected into the pumping conduit that leads directly to the pump input periodically during ALD cycling without any additional restriction between the AFR output orifice and the pump input orifice. become. In some cases, the injected gas can also be injected from an azimuth point to achieve uniform exposure and uniform residence time. An AFR orifice can also be provided with a restrictor in the form of a hole in its orifice surface, and these holes can be designed in various azimuth directions to induce a symmetric flow in the wafer surface. It is possible to apply. The TIG design can be applied by curving the inner edge of the TIG lid part to eliminate the dead space of the reaction space.

  The HP ALD design described herein is further described in the “multi-single wafer” (MSW) reactor system described, for example, in the above-mentioned US Patent Application No. 11 / 224,767 and German Patent No. 1020050563326.6. It can also be used. In that case, it is possible to house several (eg four) nearly independent HP reactors in a common vacuum housing system. In the case of DE 102005056326.6, a slight gas flow (almost countercurrent due to diffusion as opposed to convection) between otherwise independently operating reactors contained in the same master vacuum housing is present. Further needed.

  That is, in the case of a multi-single wafer system, several reaction chambers are arranged in a single process module. Substrates where circular wafers are desirable are not in a common process chamber, but instead are in separate reaction chambers associated with the exhaust zone flow dynamics. Individual reaction chambers within the process module can be loaded / unloaded during a common loading / unloading step. To do this, the substrate holder is lowered from the process position to the loading / unloading position. In the process position, the wall surface of the substrate holder forms the gas exhaust port described herein. When the substrate holder reaches the process position through the diffusion barrier, the individual reaction chambers are separated and gas flow from one reaction chamber to another is avoided. The individual reaction chambers are preferably arranged at a common height and are grouped around a center formed by the rotation axis of the loading / unloading device.

  Referring now to FIG. 3, an HP ALD system 30 configured in accordance with one embodiment of the present invention is illustrated, but quantified (minimized and optimized) with respect to a limited reaction volume 32, There is no recirculation, a symmetric flow is produced, and there is less reactant gas transport outside the HP reaction zone. System 30 includes a reaction chamber 34 as well as several components similar to those described above. Housed in the reaction chamber 34 is a vertically movable heater susceptor 36 (eg, configured as described in the above-mentioned patent owned by the assignee) on which a wafer 38 is placed. The heater susceptor 36 is connected to an annular flooring 40 whose outer periphery functions as a gas conduit. The flooring 40 includes an outlet port 42 located below the bottom surface of the wafer transport slot valve 28 when the susceptor 36 is in its process (high) position.

  The ALD system can be used for single wafer deposition or, in some cases, several smaller wafers can be placed on a single carrier in a reaction chamber. Importantly, with respect to the use of this limited design as a single stand-alone wafer reactor, the reactants are effectively shielded from adhering to the inner walls of the reaction chamber, thus improving the maintenance benefits for the single wafer reactor. That is the point.

  When the heater susceptor is in the process (high) position relative to its loading position, the annular flooring 40 attached to the outer periphery of the susceptor 36 limits the reaction of the external space of the reactor above and below the wafer with respect to the bottom surface of the flooring. The edge is provided with an external surface that separates from the space. The outer edge 44 is adjacent to an annular ring 46 attached to the reactor lid 48, and the ring 46 and the conduit outer member 44 together serve as a tongue-in-groove (TIG) structure. That is, as shown in the figure, the outer edge of the flooring fits into a groove in an annular ring attached to the reactor lid. In some cases, the TIG design can be provided with a stepped shape (SC) to limit the diffusion back flow of the downstream gas to the external space of the reactor. The annular flooring delivers exhaust reaction gas to the downstream pump orifice 16 which is off-axis with respect to the center of the reaction chamber axis.

  Design considerations for small volume symmetric flow ALD reactors require rapid and nearly uniform distribution of gas precursors to single or multiple semiconductor wafers or single or multiple workpieces with high topological features It is. To achieve the shortest exposure time and efficient precursor utilization, it is desirable to deliver chemical precursors at approximately the same concentration within approximately the same time frame to high aspect ratio features in the center and edge of the wafer.

  The advantage of exposing for the same time is to achieve an efficient conformal coating on the wafer area. The non-uniformity in the wafer of high topological features is reduced to an optimal degree, while at the same time the precursor usage is minimized. To understand this, refer to the theory for coating high aspect ratio “holes”. R. Gordon et al., “A Kinetic Model for Step Coverage by Atomic Layer Deposition in Narrow Holes or Trenches”, Chem. Vap. See Deposition, 2003, Vol. 9, No. 2, p.73 et seq. Single ALD precursor exposure is performed by gas diffusion transport from the top to the bottom of the hole. Holes located near the location on the wafer where the first precursor reaches are first coated near the top of the hole with a single pulse of the appropriate sufficient dose and then the bottom of the hole. Holes far from the location of the first precursor reaching the wafer are then coated at the bottom of their features to saturation. Reactors with distributed vertical injection are better suited to satisfy this condition efficiently, whereas reactors with horizontal injection are poor in this regard. In order to achieve an efficient coating, it is desirable to utilize a properly designed showerhead or gas distribution manifold (GDM) where gas is distributed over the wafer surface as simultaneously as possible.

  An optimal ALD system has considerations for rapid and efficient delivery of chemical precursors to the GDM and even rapid flow of the precursor into the reaction space by the GDM (for example, to the assignee of the present invention). (See Dalton et al. US Patent Application No. 11 / 278,700 filed Apr. 5, 2006, assigned and incorporated herein by reference). The detailed design of a showerhead (and high partial pressure chemical precursor source evaporator) with uniform injection and short residence time is a separate consideration from the design of the reactor itself, but is sufficiently competitive To obtain a system, it must be optimized and integrated with the best method.

  In summary, a high performance system constructed in accordance with the present invention includes a chemical precursor source capable of rapidly delivering high partial pressure precursor vapors with GDM and an optimized reaction chamber design. For the purposes of this disclosure, the chemical precursor source / delivery device, DGM, and reactor are modular with each other and are individually optimized. However, as mentioned above, an efficient and uniform coating of high topological features requires an axisymmetric exposure at approximately the same time at the center and edge of the wafer and an axisymmetric reactor design with respect to the flow at the edge of the wafer. It is advantageous to use it.

  In considering the benefits of axisymmetric flow, we discuss the benefits of symmetric flow during removal of reactants and byproducts as well as exposure. The importance of removing the precursor in azimuth symmetry is related to minimizing the occurrence of parasitic CVD at all azimuth points around the wafer edge. In addition, vortices can occur if the design results in flow recirculation in the pocket area associated with the wafer slot valve or unnecessary stagnation in the corners, regardless of whether the azimuth is symmetric. Precursor residue is present during the precursor removal / purge period and can result in parasitic CVD.

Therefore, the constraint conditions for starting the design are as follows.
a. The injected flow favors a GDM that is axisymmetric with respect to the target workpiece. For example, it can be circular (at least when it is in the processing position) aligned with the center of a circular wafer (or other workpiece) or group of circular wafers (or workpieces) that will be deposited. It can be GDM.
b. A wafer is placed on the heater susceptor using horizontal movement by robot operation via a rectangular slot valve.
c. The pumping port leading to the downstream pump can be off-axis with respect to the wafer central axis.
d. The reaction space (volume between the showerhead and the wafer surface) is minimized.
e. Minimizing the downstream volume, minimizing gas expansion that lengthens the purge time, eliminating the use of (unnecessary) downstream constrictions, and maximizing conductance from the reaction space to the downstream pump.
f. In order to improve the ALD reaction efficiency for the wafer by modifying the effective pumping speed of the downstream pump, a multi-level flow is realized without using a constricted constriction portion downstream of the injection point of the gas injection port.

  The ALD cycle time (CT) is the exposure of the first precursor, followed by removal of unused portions of the first precursor and / or reaction by-products of the first precursor (or “purge”), followed by Exposure of the second precursor and removal of unused portions of the second precursor and reaction by-products of the second precursor. The sum of these four cycle time elements is ALD CT.

  In the approach of the present invention, a limited flow path is formed by attaching a guide pumping conduit to the edge of the heater susceptor to minimize the reaction space volume. This design takes the form of a flooring where the flow path is located as close as possible to the wafer and mechanically attached to the heater susceptor. By using an annular conduit flooring attached to a vertically movable susceptor, the removal period is greatly reduced and CT is improved.

  The flooring 40 includes a conduit with an input orifice 50 at the same nominal height as the susceptor 36. When the wafer (ie, susceptor) is in the processing position, the lower orifice 42 of the flooring 40 will be located below or well below the lower edge of the slot valve 28. This constraint provides a strong separation of convection from the slot valve and improves flow symmetry just downstream of the wafer edge and wafer surface. Thereby, deep flooring (DFR) is appropriately formed. The outer edge of the DFR is placed close to the inside of the downstream reaction chamber wall 51 to minimize diffusion backflow to the slot valve and the upper outer reactor wall.

  When the vertically movable susceptor 36 with flooring 40 is raised to its “above” or processing position, the DFR outer surface component 44 is attached to the “lid ring” 46 mounted inside the reactor lid 48. Overlap at a position very close to the bottom surface of the second surface component. The inner surface of the lid ring and the outer surface of the flooring form a limiting surface for the reactant flow, limiting the reaction space.

  Iterative simulations have shown that (although) a small amount of reactant is back-diffused upstream in the flooring conduit and reaches a deliberately separated region 55 outside the lid ring. This results in an undesirable adhesion layer on the reactor wall 57 and, in the case of a multi-single wafer reactor, excessive diffusion crosstalk between the intentionally separated reactors.

  Accordingly, in one embodiment of the present invention, the lid ring 46 is configured with a recess that allows the outer surface 44 of the flooring to be inserted when in the “up” position for processing. The result is a tongue-in group (TIG) design, as shown in FIG. 4a. According to simulation, this design reduces the steady deposition rate on the outer wall of the reactor at a level 100 times the wafer deposition rate.

  By using a TIG having a stepped mating surface shape for the flooring 40 and the lid ring 46, it is possible to further reduce the diffusion backflow. This configuration is shown in FIG. 4b. In this configuration, the outer surface of the flooring 40 is divided into two portions 44a and 44b, the inner portion 44a overlapping a portion of the groove 52 formed between the inner and outer portions of the lid ring 46, and the outer portion 44b. Extends into the groove 52. The inner and outer portions 44a and 44b of the flooring that overlap and extend into the groove 52 of the lid ring 46 generally resemble a stepped structure.

  The back-diffusion reinforcement simulation for the stepped TIG design of FIG. 4b showed that the back-diffusion is reduced by a factor of 10,000 to the steady wafer deposition rate depending on the step spacing. The stepped design also addresses mechanical thermal expansion issues that could otherwise make it difficult to maintain the tolerances required in TIG designs. A multi-stage step design (eg, including multiple portions such as 44a and 44b, each overlapping a certain extent in each of the grooves 52 and extending therein, which can further reduce diffusive transport to the reactor wall. ) Is not shown (though considered within the scope of the present invention). Therefore, for the attached flooring design, there is a hierarchy of performance that can lead to a “general staircase” design using multiple stages.

  Alternatively, if a single fin component (not a double ring) is attached to the inner surface of the reactor lid and the DFR is in an overlapping position with respect to the outer ring of the susceptor while in the process position, an alternative embodiment would be Realize. However, in this case, the reaction space is limited, but the diffusion of reactants to the outer wall of the reactor at the same vertical height as the wafer is not sufficiently blocked. Similarly, if the DFR does not extend deeper than the slot valve, there will be insufficient recirculation and separation for the slot valve. These inadequate alternative embodiments show certain preferences for the combination of the attached deeper annular DFR and stepped TIG designs. According to this TIG design, the inner edge of the TIG lid part can be curved to eliminate dead space in the reaction space. For example, it is possible to use a fillet 54 that is curved as shown in FIG. 4 or has a contour as shown in FIG.

  Simulations show that the design shown in FIG. 3 results in about 10% asymmetric flow due to the off-axis pump. This off-axis pump position can be handled by placing the azimuth baffle 56 at the center to cover an azimuth of about 10 to 150 degrees to balance the azimuthal flow. Such an arrangement is shown in FIG.

  The ALD system described above is assigned to the assignee of the present invention and is incorporated by reference herein in its entirety. US Patent Application Publication No. 10 / 791,030 to Liu et al. It is possible to operate using a multi-level flow design without a restrictor downstream, as described in the bi-level flow system proposed by Sneh in US / 062490). Thus, according to an embodiment of the present invention, there is provided a TIG chamber structure as described above comprising a pump connected to remove gas flow from the reaction space, an AFR conduit, and a lower chamber leading to the pump. A gas injection orifice is provided that allows the reaction space and the AFR conduit to be bypassed so that the gas injected into the orifice flows into the flow down to the pump below the output orifice of the AFR. Thus, this orifice allows gas to be directly injected into the pumping conduit that leads directly to the pump input periodically during ALD cycling without any additional restriction between the AFR output orifice and the pump input orifice. become. In some cases, the injected gas can also be injected from an azimuth point to achieve uniform exposure and uniform residence time. The TIG design can be applied by curving the inner edge of the TIG lid part to eliminate the dead space of the reaction space, for example curved as illustrated in FIG. 4 or as illustrated in FIG. It is possible to use a fillet 54 that shows an outline.

  Maintenance aspects are also desirable. Maintenance is ultimately required due to the ALD adhesion layer on the inner wall of the deep flooring. This is accomplished by a maintenance procedure that utilizes access from the lid to the heater susceptor and then manually removes and replaces the DFR components used thereafter. The deep flooring used can be cleaned and reused.

  The simulation method and its results are described in Appendix A of the above provisional patent application, incorporated herein by reference, along with reinforcement data.

  Referring now to FIG. 6, there is shown a multi-single wafer ALD process that is similar to that described above and can include individual reaction chambers configured to include the TIG mating ring described above. A typical apparatus includes a total of two process modules 58 with four individual reaction chambers 60 each. Here, a robot arm (not shown) of the transfer chamber 62 is used to transfer the substrate from the two load locks 64 to the process module 58 so that the coating is applied in the reaction chamber 60. An atmospheric pressure wafer transfer module 68 and two adjacent load locks allow wafer transfer for loading and unloading from the vacuum transfer chamber. A cooling station 66 is also provided.

  As shown in FIG. 7, each reaction chamber includes a substrate holder 70 for supporting the substrate 72. The substrate 72 rests on a substrate holder 70 that occupies most of the area. Only the outer peripheral zone of the reaction chamber 60 formed by the shield 74 surrounding the process chamber is not occupied by the substrate holder 70. This configuration provides a circular gas discharge port 76.

  The lid or ceiling of all reaction chambers 60 includes a supply orifice (such as GDM) component 78 surrounded by a circular shield 74. The process gas and carrier gas inlets 80 together form an inlet orifice. Gas is supplied by the gas inlet 80 so that the amount of gas exceeds almost the entire level of the supply orifice 78. The air supply orifice 78 features a number of sieve-like gas discharge openings (not shown in this figure) on its lower side facing the reaction chamber 60. The process gas and the carrier gas can flow into the reaction chamber 60 through these gas discharge openings.

  That is, in this embodiment, the gas flows horizontally (after vertical injection) and passes radially through the reaction chamber to the outer peripheral area where it is redirected downward by the shield 74 in the vertical direction. The gas then flows through the circular gas exhaust channel 76 formed by the channel inner wall 82 and the channel outer wall 84. The gas flowing from the gas exhaust channel 76 flows into a common gas exhaust conduit 86 that surrounds the central axis 98 of the process module. The common gas discharge conduit 86 can be connected to a foreline and a vacuum pump.

  The channel inner wall 82 is also the outer wall of the substrate holder 70. The substrate holder 70 forms a main body shaped like a pot that is inverted upside down. The flat outer wall (or “bottom surface”) of the pot forms the support surface of the substrate 72. The outer wall 82 of the cylindrical pot wall surface forms the inner wall of the gas discharge port 76. A channel outer wall 84 separated from the channel inner wall 82 by a gap is securely connected to the channel inner wall 82 and thus to the substrate holder 70. Ribs or struts can be utilized for this secure connection (not shown).

  The upper segment 90 of the channel outer wall 84 (stepped design “kick up”) fits into the ring groove of the sealing ring 92 located radially outward relative to the shield when the substrate holder 70 is in its process position. In the upper segment 90, the material thickness of the channel outer wall 84 is gradually reduced according to the design. The sealing ring 92 is formed with a ring groove having an open bottom surface into which the segment 90 of the channel outer wall 84 can be inserted. Thereby, a gas sealing is provided between the reaction chamber 60 and the gap space 94. The channel outer wall (of deep flooring) also forms a (gas diffusion flow) sealing surface for the inner wall 96 of the gas exhaust conduit 86. Accordingly, the gas flowing through the gas exhaust conduit 86 cannot reach the gap space 94. As the substrate holder 70 is lowered from the process position to the loading position, the outer surface of the pipe-shaped outer channel wall 84 moves along the inner wall 96 of the gas exhaust conduit 86 (with a slight spacing).

  As shown, the ALD device can be symmetric with respect to the central axis 98. It is also possible to provide a lift pin 100 (functioning through the opening 102 of the substrate holder 70). The substrate holder 70 is supported by the pedestal 104 and the reaction chamber can include an upper portion 106.

  Starting from the position shown in FIG. 7, since the lift pins 100 are retracted, the substrate 72 is positioned at the contact points 108 and 110. FIG. 8 shows the substrate holder in its lower (loading / unloading) position in the reactor 60. In order to send the substrate 72 to and from the reactor, the drive mechanism (not shown) lifts the substrate using the lift pins 100 pushed from the retracted position to the substrate support position shown in FIG. It can be supported by lift pins at a position above the possible height. In this way, it becomes possible to sequentially load and remove substrates from the reaction chamber.

  FIG. 8 shows an enlarged view of the seal interface where the segment 90 of the channel outer wall 84 is inserted into the ring groove 114 of the sealing ring 92.

  Thus, when the substrate holder is in the process position, the upper segment of the channel wall firmly connected to the substrate holder fits into the groove of the circular sealing ring covered by the shield. The circular shield 74 and the sealing ring 92 can be integrated into a single piece part. The circular shield 74 forms the outer peripheral wall of the process chamber, extends vertically downward from the air supply orifice, is surrounded by its inner wall 82 and outer wall 84, and the inner wall is firmly connected to the substrate holder 70. The discharge channel 76 is reached. When the substrate holder is lowered from the aforementioned process position where layer growth on the substrate surface occurs to the loading / unloading position, the gap space between the individual process chambers is opened. In this loading and unloading position, the substrate holder is located below the gap space. The substrate holder is characterized by an opening for penetrating the lift pins. The lift pins are lifted by a lift mechanism to lift the substrate from below and pull it away from the substrate holder. To perform the loading and unloading operations, the reaction chamber features a side slot opening that allows the robotic arm to enter the reaction chamber. The substrate holder is carried by a lift shaft that can shift the substrate holder vertically as described above.

  This concludes the description of the small volume symmetric flow (SVSF) apparatus defined with respect to the minimum ALD reaction volume that produces symmetric flow with minimal chemical transport to the reactor wall. While specific illustrative embodiments have been discussed, the invention is not intended to be limited thereto, but should only be determined by the appended claims.

FIG. 2 illustrates an ALD reactor with vertical precursor injection and radius / vertical flow pumping. It is the figure which illustrated the off-axis downstream pump which destroys the symmetry of the radial gas flow in a slot valve and an ALD apparatus. FIG. 5 illustrates a deep flooring (DFR), wafer slot valve position, and relative orientation of a DFR orifice below the slot valve in an ALD apparatus configured in accordance with one embodiment of the present invention. FIG. 4 is a detailed view of an ALD apparatus with a tongue-in-groove (TIG) structure according to one of the embodiments of the present invention showing an alternative staircase shape design and removal of dead zones at the corners of the reaction space by forming fillets that direct gas to the DFR. FIG. 6 illustrates the use of a downstream baffle to symmetrize the upstream flow of an ALD apparatus according to one embodiment of the present invention. An ALD multi-single wafer (MSW) process equipment comprising a total of two process modules each provided with a transfer chamber with four reaction chambers and associated load locks, constituted by one of the embodiments of the present invention. It is a top view of a layout. It is sectional drawing of the reaction chamber of MSW apparatus shown in FIG. FIG. 7 is a diagram illustrating in more detail the reaction chamber of the MSW device shown in FIG. 6 with its vertically movable susceptor in its low (loading / unloading) position.

Claims (16)

  The heater susceptor is configured as a gas conduit and is coupled to an annular attached flooring with an outlet port extending below the bottom surface of the wafer transport slot valve of the reaction chamber apparatus when the vertically movable heater susceptor is in the processing position. , Reaction chamber equipment.   A heater susceptor having an outer periphery coupled to an annular attached flooring conduit, the flooring conduit being external to the reactor above and below the wafer position relative to the bottom surface of the flooring when the heater susceptor is in the processing position. Reaction chamber apparatus, characterized in that the edge is provided with an external surface separating the spaces.   A heater susceptor having an outer periphery coupled to an annular attached flooring conduit is included, and the flooring conduit defines a space outside the reaction chamber above the wafer position when the heater susceptor is in a processing position. An outer surface separated from the reaction space is provided at the edge, the edge being adjacent to an annular ring attached to the reactor lid, and a tongue-in groove (TIG) structure is formed by the annular ring and the outer member of the conduit. A reaction chamber device, characterized in that it is formed.   The reaction chamber apparatus according to claim 3, wherein the TIG structure includes a stepped shape that serves to limit the diffusion and backflow of the downstream gas to the external space of the apparatus.   A vertically movable susceptor, the outer periphery of which is coupled to an annular attached flooring conduit, is included, and the annular attached flooring delivers exhaust reaction gas to a downstream pump orifice disposed off-axis relative to the axial center of the reaction chamber The reaction chamber apparatus is configured as described above.   6. The reaction chamber apparatus according to claim 5, further comprising a downstream baffle disposed between the lower orifice of the annular attached flooring and the downstream pump.   4. The reaction chamber apparatus of claim 3, further comprising a pump coupled to remove gas flow from the reaction chamber, the flooring conduit, and a lower chamber leading to the pump.   In addition, a gas injection orifice coupled to allow bypassing of the reaction chamber and the flooring conduit is included, and the gas injected into the orifice flows into the flow leading to the pump below the output orifice of the flooring. The reaction chamber apparatus according to claim 7, wherein the reaction chamber apparatus is configured as follows.   The reaction chamber apparatus according to claim 8, wherein the gas injection orifice is configured to inject gas from an azimuth point.   9. The reaction chamber apparatus of claim 8, wherein the flooring orifice includes a restrictor in the form of a hole in the orifice surface.   The reaction chamber apparatus according to claim 10, wherein the hole is variously configured in various azimuth directions.   The reaction chamber apparatus according to claim 3, wherein an inner edge of the lid is curved.   An ALD apparatus including a plurality of process modules, each process module having one or more reaction chambers, and each reaction chamber being vertically movable between a process position and a loading / unloading position For each individual holder of the substrate holder, so that a gas discharge port is formed in the respective reaction chamber when the respective substrate holder is in its process position. An ALD apparatus characterized in that an orientation is applied and the port is formed by an outer peripheral wall of each reaction chamber and an edge surface of each substrate holder.   14. The apparatus of claim 13, wherein a wall surface of the gas exhaust port channel is attached to the substrate holder and is movable therewith.   The apparatus of claim 13, wherein an upper segment of an outer wall segment of the gas exhaust port channel is disposed within a ring groove.   The ALD apparatus according to claim 15, wherein the ring groove is fitted around a circular shield that fits around an air supply distributor of each individual reaction chamber.

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