KR101505497B1 - Small volume symmetric flow single wafer ald apparatus - Google Patents

Abstract

The ALD reactor chamber includes a vertically moved heater-susceptor having an annular attached flow ring conduit therearound, the conduit having a heater-susceptor disposed about the bottom of the flow loop when the heater- And has an outer surface at its edge separating the outer space of the reactor above the wafer and below the wafer. When the susceptor is placed in the processing position, the outer edge of the flow loop is located close to the annular ring attached to the Hd of the reactor and forms the configuration of the grooved body (TIG) with the ring and the conduit. In some cases, the TIG design has a stepped contour (SC), thereby limiting diffusion-backflow of the downstream gas to the exterior space of the reactor.

Description

TECHNICAL FIELD [0001] The present invention relates to a small-sized, single-wafer atomic layer deposition apparatus,

SUMMARY OF THE INVENTION The present invention is based on the discovery that a small, symmetrical flow-type atom that improves the ALD cycle time by minimizing the volume of the reaction space while maintaining the symmetry of the gas flow associated with the off-axis wafer transfer slot valve and / Layer deposition (ALD) device.

The ALD reactor can have a variety of design configurations. The construction of a conventional single wafer ALD reactor includes a cross-flow design in which continuous exposure (pulses) of the chemical precursor and removal (purge) of the injected gas are carried out substantially And they are also pumped out in the horizontal direction and discharged. The transfer of the wafers can take place in the same horizontal plane at right angles to the gas flow direction. The term "traveling wave" is used to refer to the movement of a precursor pulse in a time-dependent manner from an injection orifice to a pump orifice (see, e.g., T. Suntola, "Atomic Layer Epitaxy" in Handbook of Crystal Growth 3 , Huerle ed., Ch. 14, pp. 601 et seq. (1994).

In a so-called "pure" ALD process, the first precursor is completely removed from the reaction space before the second precursor is introduced (see S. M. Bedair, "Atomic layer epitaxy deposition processes," Sci. Tech. B12 (1), Jan / Feb, pp. 179 et seq. (1994). However, undesirable parasitic chemical vapor deposition (CVD) occurs at the edge of the wafer in the traveling wave direction as the wafer becomes larger in size, e.g., 300 mm and 450 mm, and the cycle time approaches the lower limit. This parasitic CVD is due to undesirable chemical reactions resulting from the simultaneous coexistence of the dispersion tracer portion of the first precursor and the remaining precursor at the beginning of the second precursor in time and space. To avoid this parasitic CVD, the removal of the precursor between the pulses is used. This often requires a long removal time. In a horizontal single wafer design, the concentration of the trailing edge of the first precursor pulse must be reduced to a minor level, e. G., Any value less than about 1% of the first precursor peak value, to avoid such parasitic CVD For example, in US Pat. No. 6,015,590 to Suntola.

Since ALD is a self-limiting process, the direction and flow symmetry of the precursor is not important, as CVD will be meaningless if sufficient time is used for the precursor removal period - generally referred to as the "purge period & Can be discussed. However, for high deposition rates (thickness / unit time or low cycle time), flow symmetry becomes important as the purge time approaches the lowest possible time for commercial manufacturing values.

An alternative single wafer design utilizes precursor gas injected from a line-centered and line-symmetrical vertical gas distribution module (GDM) (e.g., using a line-centered orifice or showerhead) The tail is advantageously limited to overlap in the wafer radius (1/2 of the diameter) in the case of high despreading, allowing for faster pumping (pumped at all azimuths) and removal of unused and byproduct gases do.

Currently, many single wafer commercial ALD reactors utilize vertical precursor implantation where vertical pumping occurs after radial flow. Figure 1 shows such an ALD reactor system 10 in which two precursors A and B are injected vertically into the reaction chamber 14 through valves 12a and 12b. Gas is extracted from the chamber 14 by a pump 16. As shown, the gas flow in the chamber 14 is initially directed to another injector 18 or shower (not shown) positioned linearly symmetrically on the wafer 20, for example, typically supported by the susceptor 22, Perpendicular to the head, and then radially outward from the center of the wafer 20 to its edge. Thereafter, the gas is pumped out of the chamber 14 in a vertical flow, and in this case a combined radial / vertical flow pumping is provided. Ideally, such a configuration provides flow symmetry at the wafer edge.

As shown in Figure 2, in a commercial single wafer system, the wafer to be processed is introduced into the reactor by a robotic center handler 24. These wafer transfer devices are also commonly used in CVD devices used in the silicon chip manufacturing industry. The wafer 26 typically is introduced at a particular azimuth and range on the outer surface or the radius of the reaction chamber 14 adjacent to the reactor wall (θ ₁ and Δθ ₁₎ through a rectangular slot valve (28). This slot valve 28 and its rectangular passage into the chamber 14 breaks the symmetry of the radial gas flow as schematically shown in the figure.

In addition, the downstream drainage pump 16 is usually set in the range and azimuth (θ ₂ and Δθ _2), wherein θ ₂ is typically does not have to be the same as θ _1. Even if such an arrangement accommodates on-axial mechanical drive support hardware to allow vertical movement of the susceptor, this asymmetry can create circulating pockets, stagnation zones and / or pumping azimuth non-uniformities. For example, if residual precursors are removed from the first precursor stream by pumping or by uneven azimuthal flow from the wafer, additional devices are provided to allow the parasitic CVD to occur asymmetrically or non-uniformly in one azimuthal direction of the wafer . In this case, the beginning of the parasitic CVD occurs asymmetrically and permanently over a certain azimuthal direction or angle (s) due to recirculation, stagnation and / or pumping effects.

It is known in the art that the volume of the reaction space (the space above the wafer between the wafer and the precursor injection part (e.g., showerhead)) is well known in the art (see, for example, M. Ritala and M. Leskela , "Atomic Layer Deposition" in Handbook of Thin Film Materials, H. Nalwa, ed., Vol. 1, Ch. 2, pp. 103 et seq. (2002). In order to decrease the precursor removal time, the retention time (PV / F, where P is the pressure, V is the volume of the reaction space and F is the flow through the reaction space) and thus the ALD cycle time, The volume should be minimized. Using a vertically movable susceptor design (see, for example, U.S. Patent No. 5,855,675 to Doering et al., Assigned to the assignee of the present invention and incorporated herein by reference) And the gas distribution orifice (showerhead) in the reactor lid can be optimized to make the flow and residence time uniform; That is, the volume of the reaction space can be minimized while locally limiting uniform exposure. In addition, the reaction space may include an annular zone between the susceptor edge and the upper reactor inner wall for parasitic reaction space.

The broken flow symmetry due to the wafer slot valve and azimuthal placement of the wafer passageway is achieved by using a vertically movable susceptor / heater configured to position the wafer above the wafer slot valve when the wafer and its heater / Although substantially recovered, this method was still limited in terms of fine control of the symmetrical flow. For example, a vortex can be formed in the pocket associated with the wafer slot valve below the wafer plane when the downstream gas continues to form a stagnation zone and the susceptor is placed in its processing position. Therefore, there is a need for a reactor design that provides minimal reaction space volume and improved symmetric flow while retaining the ability to work with conventional wafer (slot) transfer devices. The present invention provides a solution to this requirement and provides a less limited volume with symmetrical flow, which provides a high throughput, high performance (HP) single wafer reactor.

Summary of the Invention

In one embodiment of the present invention, the reaction chamber apparatus comprises a vertically movable heater-susceptor which, when the susceptor is in a machined (higher) position, Is connected to an annular attached flow loop which acts as a gas conduit, with an outlet port of the flow loop extending downward.

Another embodiment of the present invention provides a reaction chamber apparatus comprising a heater-susceptor coupled to an annular attached flow ring conduit around a susceptor, the conduit having a heater- Has an outer surface at its edge that separates the outer space of the reactor above the wafer and below the wafer from the bottom of the flow loop from the limited reaction space when placed in the processing (higher) position.

In another embodiment, the present invention provides a reaction chamber apparatus comprising a heater-susceptor coupled to an annular attached flow ring conduit around a susceptor, the conduit having a heater- Has an outer surface at its edge that separates the outer space of the reactor above the wafer from the limited reaction space when placed in the processing (higher) position, the outer edge being located proximate to the annular ring attached to the reactor lid, And acts as a tongue in groove (TIG) configuration with the conduit outer member. In some cases, the TIG design has a stepped geometry to limit the back flow of downstream gas to the reactor exterior space.

Another embodiment of the present invention provides a reaction chamber apparatus having a vertically movable susceptor (VMS) for loading (lower) position, the susceptor having an annular attached flow loop (AFR) around the susceptor, (Or deep flow loop (DFR)) conduit, which moves the reaction gas effluent to a downstream pump that is off-axis with respect to the line-centered center of the reaction chamber. In some cases, a downstream baffle 56 may be positioned between the output orifice 42 of the annular AFR and the downstream pump 16 to provide a symmetrical gas flow at the wafer edge within the upstream wafer plane.

Another embodiment of the present invention provides a configuration of a TIG chamber as described above and having a reaction chamber, an AFR conduit, and a pump connected to remove the gas stream from the bottom chamber leading to the pump. The gas injection orifices that can bypass the reaction space and the AFR conduits are positioned such that the gas injected through the orifices enters the stream connected to the pump below the output orifice 42 of the AFR. Therefore, this orifice injects gas directly into the pumping conduit, which is directly connected to the input of the pump, periodically during the ALD periodicization, without any additional squeezing device between the output orifice 42 of the AFR and the downstream pump orifice.

In another embodiment, the ALD apparatus includes a plurality of process modules, each process module having one or more reactor chambers, each reactor chamber having a vertically movable substrate holder between a working position and a load / unload position And each of the substrate holders is oriented in a respective reactor chamber such that a gas outlet port is formed in each of the reactor chambers when each substrate holder is in a working position, And is formed by the edge surface of the substrate holder. The wall of the gas outlet port channel is attached to the substrate holder and can move with it. It is preferred that the upper section of the outer wall section of the gas outlet port channel be located within the annular groove 114 which is itself a circular shield (not shown) that fits around the gas inlet distributor of each reactor chamber circular shield.

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

The invention is illustrated by way of non-limiting example with reference to the accompanying drawings:

Figure 1 shows an ALD reactor in which a precursor is injected vertically and a combined radial / vertical flow pumping occurs.

Figure 2 shows a slot valve and an off-axis downstream pump that breaks the symmetry of the radial gas flow within the ALD device.

Figure 3 illustrates the relative orientation of the deep flow loop (DFR), wafer slot valve position and output orifice 42 of the DFR under the slot valve in an ALD device constructed in accordance with one embodiment of the present invention.

Figures 4A and 4B illustrate the removal of the unused zone at the corners of the reaction space by a coutoured fillet of the gas into the DFR and the removal of the unused zone and the alternative stepwise design of the trough in accordance with one embodiment of the present invention. And Fig.

5 illustrates the use of a downstream baffle 56 to symmetry the flow upstream in an ALD apparatus according to one embodiment of the present invention.

Figure 6 shows an ALD having a total of two process modules, constructed in accordance with one embodiment of the present invention, with four reactor chambers and one transfer chamber, with each module associated with a load lock. Top plan view of a multi-single wafer (MSW) process apparatus.

Figure 7 shows a cross-sectional view of the reactor chamber of the MSW apparatus shown in Figure 6;

Figure 8 shows in further detail the reactor chamber of the MSW apparatus shown in Figure 6 with a vertically movable susceptor in a lower (load / unload) position.

A small-scale, symmetrical flow (SVSF) device is described herein for a minimum ALD reaction volume with a symmetrical flow while minimizing chemical transfer to the reactor wall. This description includes not only the reactor design and its functionality, but also a discussion of the combinatorial effect of the small space for the reaction space, a generalized design for separating the reaction space from the reactor walls without recirculation, minimization of the gas expansion volume below the wafer plane, And a time-phased multi-level controlled downstream pump arrangement that is suitably designed to achieve flow symmetry in an off-axis pumping conduit with maintainability and assembly characteristics in all cases.

In one embodiment of the present invention, the reaction chamber apparatus comprises a vertically movable heater-susceptor which, when the susceptor is in a machined (higher) position, Is connected to an annular attached flow loop which acts as a gas conduit, with an outlet port of the flow loop extending downward.

Another embodiment of the present invention provides a reaction chamber apparatus comprising a heater-susceptor connected to an annular attached flow ring conduit around a susceptor, the conduit having a heater-susceptor for processing Higher position), the outer surface at its edge separating the outer space of the reactor above the wafer and below the wafer from the bottom of the flow loop from the limited reaction space.

In yet another embodiment, the present invention provides a reaction chamber apparatus comprising a heater-susceptor connected to an annular attached flow ring conduit around a susceptor, wherein the conduit is configured such that the heater- Has an outer surface at its periphery that separates the reactor outer space above the wafer from the confined reaction space when placed in the processing (higher) position, the outer edge being located proximate the annular ring attached to the reactor lid, (TIG) together with the outer member. In some cases, the TIG design has a stepped contour (SC), which can limit the diffusion-backflow of the downstream gas to the outside space of the reactor.

Significantly, in embodiments of the present invention, the design and operation of the tongue and groove 52 members are such that they are not in physical contact with each other. The contact member will be a particle source device, which can induce adhesion by metal-to-metal contact (metal bonding in vacuum) and compromise the shrinkage of the heater-susceptor. In addition, the contact design will have considerable difficulty in maintaining mechanical stability. For this reason, the present inventors have designed and operated a "near" or "diffusion-seal" TIG device.

Another embodiment of the present invention provides a reaction chamber device with a vertically movable susceptor (VMS) for a loading (lower) position, the susceptor having an annular attached flow loop AFR) (or deep-flow loop (DFR)) conduit, which moves the reaction gas effluent to a downstream pump orifice that is off-axis with respect to the line-centered center of the reaction chamber. In some cases, the downstream baffle 56 may be located between the output orifice 42 of the annular AFR and the downstream pump 16 to form a symmetrical gas flow at the wafer edge in the upstream wafer plane.

Another embodiment of the present invention provides a TIG chamber configuration as described above and having a pump connected to remove the gas stream from the reaction space, wherein the AFR conduit and the lower chamber are connected to a pump. The gas injection orifices that can bypass the reaction space and the AFR conduit are positioned such that the gas injected through the orifice enters the stream leading to the pump below the output orifice 42 of the AFR. Therefore, the orifice injects the gas directly into the pumping conduit, which immediately follows the input of the pump, without additional contraction device between the output orifice 42 of the AFR and the downstream pump orifice periodically during the ALD periodization. In some cases, the injected gas may be injected at an azimuth point to achieve a uniform exposure and a uniform residence time. Also, the orifice of the AFR may have a hole-shaped retraction device in the plane of the orifice, and the hole may be designed differently in different azimuthal directions to induce a symmetrical flow in the wafer plane. This TIG design may be such that the inner edge of the TIG lid member is curved to eliminate unused space in the reaction space.

The HP ALD design described herein is described in more detail, for example, in US patent application Ser. No. 11 / 224,767, referenced above, and in "Multiple-Single Wafer (MSW)" reactor systems as described in German Patent Application DE 102005056326.6 . ≪ / RTI > In that case, a plurality (e.g., four) of substantially independent HP reactors may be located in a common vacuum housing system. In DE 102005056326.6 there is an additional requirement of less gas flow (mainly counter diffusion flow, as opposed to convective flow) between other substantially independently operating reactors located in the same master vacuum housing.

More specifically, in a plurality of single wafer systems, a plurality of reactor chambers are arranged in a single process module. The substrate, which is preferably a circular wafer, is not placed in a common process chamber, but rather is placed in a separate reactor chamber which is connected to the flow power in the gas discharge zone. The individual reactor chambers in the process module can be loaded / unloaded during a common load / unload phase. To do this, the substrate holder is lowered from the working position to the load / unload position. At the processing position, the walls of the substrate holder form the gas discharge outlet port described herein. The individual reactor chambers are separated when the substrate holder is placed in the processing position through the diffusion barrier to prevent gas flow from one chamber to the other. The individual chambers are preferably arranged at a common height and gathered about a center formed by the rotational axis of the load / unload device.

Referring now to Figure 3, there is shown an HP ALD system 30 constructed in accordance with an embodiment of the present invention, which includes a limited reaction volume 32 (minimized and optimized) that is not recirculated, , Symmetry flow, and little gas reactant transport outside the HP reaction zone. The system 30 includes a reactor chamber 34 and a number of components similar to those described above. A vertically moveable heater-susceptor 36 (e.g., configured as discussed in the referenced patent owned by the present assignee) is accommodated in the chamber 34, and the heater-susceptor 36 The wafer 38 is placed. The heater-susceptor 36 is connected to an annular flow loop 40, which acts as a gas conduit, around it. The flow loop 40 has an outlet port 42 located below the bottom of the wafer transfer slot valve 28 when the susceptor 36 is in its processing (higher) position.

The ALD system of the present invention may be used for single wafer deposition, or, in some cases, multiple smaller wafers may be located on a single carrier within the chamber. Importantly, the reactants are advantageously protected from being deposited on the inner wall of the reactor chamber in that they use this limited design as a single, sole-standing wafer reactor, and are advancing in the maintenance advantages for a single wafer reactor .

An annular flow ring conduit 40 attached around the susceptor 36 is configured to allow the heater-susceptor 40 to move relative to the bottom of the flow loop from the reaction space defined when the heater- And an outer surface 44 at its edge separating the outer space of the reactor below the wafer. The outer edge 44 is proximate to an annular ring 46 attached to the reactor lid 48 and acts in combination with the ring 46 and conduit outer member 44 to form an in- . That is, as shown in the figure, the outer edge of the flow loop is fitted within the groove 52 in the annular ring attached to the reactor lid. In some cases, the TIG design has a stepped geometry (SC), which can limit the diffusion-backflow of the downstream gas to the outside space of the reactor. The annular flow loop moves the reaction gas effluent to the downstream pump 16, which is off-axis with respect to the line-centered center of the reaction chamber.

In the design of a small, symmetrical flow ALD reactor, it should be considered to transfer the gas precursor quickly and substantially uniformly across semiconductor wafers or wafers or workpieces or workpieces with high phase characteristics. In order to obtain a minimum exposure time and the use of efficient precursors, the inventors wish that the chemical precursors will have high aspect properties at the center and edges of the wafer within approximately the same period, with approximately the same concentration.

An advantage of simultaneous exposure is that an efficient conformal coating is achieved across the wafer area. The non-uniformity in the wafer with high phase characteristics will be minimized optimally and at the same time a minimum amount of precursor will be used. To understand this, the present inventors have referred to the theory of "hole " coating with a high aspect ratio [R. Gordon, et al., "A Kinetic Model for Step Coverage by Atomic Layer Deposition in Narrow Holes or Trenches," Chem. Vap. Deposition, 9, No. 2, pp. 73 et seq. (2003). Exposure of a single ALD precursor proceeds by gas diffusion transfer from the top to the bottom of the hole. A hole located near the position on the wafer where the first precursor is reached will first coat the vicinity of the topmost portion with a suitably sufficient amount of a single pulse and then coat the hole bottom. Holes remote from the position at which the first precursor reaches the wafer will then sufficiently coat the bottom with these properties. Reactors with distributed vertical injection are more suitable for efficiently meeting these conditions, while reactors with horizontal injection are poorly operated in this respect. In order to obtain an efficient coating, it is desirable to use a suitably designed showerhead or gas distribution manifold (GDM) in which the gas is dispensed simultaneously over the entire wafer surface as much as possible.

Optimal ALD systems include the consideration of GDM to provide rapid and efficient transfer of chemical precursors into the GDM and, in turn, rapid precursor flow to the reaction space (see, for example, application filed on April 5, 2006 And U.S. Patent Application Serial No. 11 / 278,700 to Dalton et al., Assigned to the assignee of the present invention and incorporated herein by reference). The detailed design of showerheads (and high partial pressure chemical precursor source vaporizers) with uniform injection and short residence time is considered separate from the design of the reactor itself, but the design is optimized for optimum performance Optimized and integrated.

In summary, a high performance system constructed in accordance with the present invention includes a chemical precursor source that can rapidly deliver high partial pressure precursor vapor by GDM, and an optimized reactor chamber design. To this end, the inventors contemplate chemical supply / transport, GDM and reactor optimized as modules for each other and individually. However, as noted above, for efficient and uniform coating with high phase characteristics, the present inventors have found that the symmetrical exposure at the center and edge of the wafer at approximately the same time, and the reactor design that is symmetrical about the flow at the wafer edge, .

In light of the advantages of the line-symmetric flow, we discuss the benefits of symmetrical flow during exposure, and removal of reactants and byproducts. The importance of removing the precursor using azimuthal symmetry is related to minimizing the onset of parasitic CVD at all azimuthal points around the wafer edge. Also, whatever the azimuthal symmetry or otherwise, if the flow is recirculated or stagnated at unnecessary corners in the pocket region associated with the wafer slot valve by design, a vortex can be created and the precursor residue is removed / Remains during the purge period and can induce parasitic CVD.

Therefore, the start-up limitations of the design include:

a. The injection flow supports GDM with a linear-symmetric geometry for the target workpiece. For example, it may be a circular GDM with center (if at least in the machining position) aligned with the center of the circular wafer (or other workpiece), or a group of circular wafers (or workpieces) on which deposition takes place.

b. The wafer is positioned on the heater-susceptor using a horizontal movement by a robotic process through a rectangular slot valve.

c. The pumping port leading to the downstream pump may be off-axis with respect to the center wafer axis.

d. The reaction space (the volume between the showerhead and the wafer surface) must be minimized.

e. The downstream volume must be minimized, the gas expansion causing the long purge time to be minimized, the use of (unneeded) downstream contraction eliminated, and the conductance from the reaction space to the downstream pump must be maximized.

f. Multi-level flow can be obtained without using shrinkage restrictions on the downstream side of the introduction point of the gas influent to improve the ALD reaction efficiency for the wafer by changing the effective pumping rate of the downstream pump.

The ALD cycle time (CT) is determined by the exposure of the first precursor, subsequent removal of the first precursor and subsequent removal of the first precursor reaction product (or "purge"), and subsequent exposure of the second precursor, And removal of the second precursor reaction by-products. The sum of these four periodic time elements is ALD CT.

In our method, a confined flow path is formed by attaching an inner chamber pumping conduit to the edge of the heater-susceptor to minimize the volume of the reaction space. This design places the flow path as close to the wafer as possible and takes the form of a flow loop mechanically attached to the heater-susceptor. Removal time is greatly reduced and CT is improved by using an annular conduit flow loop attached to a movable vertical susceptor.

The annular flow ring has a conduit 40 having an input orifice 50 at the same nominal height as the susceptor 36. The output orifice 42 of the annular flow annulus 40 is located beneath or substantially below the lower edge of the slot valve 28 when the wafer (i.e., the susceptor) is in the working position. This limitation provides for good convective flow separation from the slot valve and improves flow symmetry just below the wafer edge and the wafer surface. A deep-drawn ring (DFR) is then suitably formed. The outer edge of the DFR is located close to the inside of the downstream reactor chamber wall 51 to minimize diffusional backfire against the outer valve wall surface of the slot valve and top.

When the vertically movable susceptor 36 with the flow loop 40 is raised to its "up" or to the working position, the outer surface member 44 of the DFR is located inside the lid 48 of the reactor Quot; cover-ring "46 to which it is attached. The inner surface of the sheath ring member and the outer surface of the flow loop form a defined surface for reactant flow and provide a restriction to the reaction space.

By repetitive simulation tests, some small amount of reactant despreads the upstream flow in the conduit of the flow loop, reaching the intentionally separated region 55 outside the cover ring. This creates undesirable deposits on the reactor walls 57 and, in the case of multiple single wafer reactors, excessive diffusive crosstalk between intentional independent reactors.

Therefore, in one embodiment of the present invention, the cover ring 46 is comprised of a recess that allows insertion of the outer surface 44 of the flow ring into the recess when positioned "up" for processing. The result is a "in-groove design (TIG)" design as shown in FIG. Simulation shows that from this design a reduction in steady state deposition rate on the outer reactor wall by a factor of about 100 is achieved relative to the wafer deposition rate.

A further reduction in diffusional backflow can be obtained by using a TIG having a stepped contour harmonized with the flow ring 40 and the cover ring 46. This configuration is shown in FIG. 4B. In this configuration, the outer surface of the flow ring 40 is divided into two portions 44a, 44b, the inner portion 44a having a groove 52 portion formed between the inner and outer portions of the cover ring 46 And the outer portion 44b extends into the groove 52. As shown in Fig. Together, the inner and outer portions 44a, 44b of the flow loop resemble a stepped, similar structure that overlaps and extends into the groove 52 of the cover ring 46.

The back-diffusion supporting simulation for the step-like TIG design of FIG. 4B shows that a maximum 10,000-fold reduction in back-diffusion compared to steady-state wafer deposition varies with the space within the stepped structure. The step-like design also addresses the mechanical thermal expansion problem that can create the necessary tolerances in a otherwise difficult to maintain TIG design. Multiple levels of stepped design (e.g., multiple portions such as 44a and 44b, which overlap and extend at successive distances in the grooves 52, respectively, which can further reduce diffusive transport to the reactor wall) Are not shown (although they are contemplated within the scope of the present invention). Thus, there is a performance scheme for an attached flow loop design that can lead to a "generalized stepped" design, using multiple steps.

Alternatively, an alternative embodiment is realized when a single fin member (rather than a double loop) is attached to the inner surface of the reactor lid and the DFR is located in an overlapping position with respect to the outer ring of the susceptor during the working position . However, in this case, the reaction space will be limited, but the reactant diffusion to the reactor outer wall at the same vertical height as the wafer will not be well separated. Similarly, if the DFR is not limited as it extends deeper than the slot valve, recirculation and separation for the slot valve will be poor. This poor alternative means that an annular extended DFR with attached depth combined with a stepped TIG design is particularly preferred. The TIG design can be made such that the inner edge of the TIG lid element is curved to eliminate unused space in the reaction space. For example, a curved or countered contour 54 as shown in Fig. 4 may be used.

From the simulation, it is confirmed that the design shown in Fig. 3 shows an asymmetric flow of about 10% due to the off-axis pump. The position of such an off-axis pump can be designed by placing a downstream baffle 56 over an azimuth angle of about 10 to 150 degrees centered to balance the azimuthal flow. Such a configuration is shown in Fig.

The above-described ALD system is described in U. S. Patent Application No. 10 / 791,030 to Liu et al., Which is assigned to the assignee of the present invention and which is incorporated herein by reference and does not require a downstream shrinkage device Level flow design proposed by Sneh in < RTI ID = 0.0 > U. < / RTI > Thus, embodiments of the present invention may provide a TIG chamber configuration, as described above and having a pump connected to remove the gas stream from the reaction space, wherein the AFR conduit and the lower chamber are pumped. The gas injection orifices that can bypass the reaction space and the AFR conduits are positioned such that the gas injected through the orifices enters the stream leading to the pump below the output orifice 42 of the AFR. Thus, the orifice injects gas directly into the pump conduit, which is connected directly to the input of the pump, without any additional squeezing device between the output orifice 42 of the AFR and the downstream pump orifice periodically during ALD periodization. In some cases, the injected gas may be injected at the azimuth point to achieve a uniform exposure and a uniform residence time. The TIG design may be such that the inner edge of the TIG lid member is curved to eliminate unused space in the reaction space. For example, a curved or projected contour 54 as shown in Fig. 4 may be used.

Maintenance characteristics are also desirable. ALD deposits on the inner wall of the deep-run loop will ultimately require maintenance. This is accomplished by manual removal and replacement of the used DFR components followed by a maintenance procedure using a lid-access to the heater-susceptor. The deep-flow rings used can be cleaned and reused.

Simulation methods and results with support data are given in Appendix A of the above-cited patent application, which is incorporated herein by reference.

Referring now to FIG. 6, there is shown a plurality of single wafer ALD process devices, similar to those described above, that may include individual reactor chambers configured using the TIG-fitted rings discussed above. The illustrated apparatus includes a total of two process modules 58, each having four separate chambers 60. The process chambers 60, 6, with the help of the robotic arm of the transfer chamber 62, the substrate can be transferred from the two load locks 64 into the process module 58, Is coated in the chamber (60). The atmospheric wafer transfer module 68 and two adjacent load locks provide wafer transfer for loading and unloading into and out of the vacuum transfer chamber. A cooling station 66 is also provided.

As shown in FIG. 7, each of the reactor chambers includes a substrate holder 70 for supporting a substrate 72. The substrate 72 is located on the substrate holder 70 and covers most of its area. However, the outer peripheral region of the chamber 60, which is formed by the shield 74 surrounding the process chamber, is not covered by the substrate holder 70. With this configuration, a circular gas discharge port 76 is formed.

The cover or ceiling of all chambers 60 includes a component 78 of gas inflow orifices (such as GDM) surrounded by a circular shield 74. The process gas and the gas influent 80 for the carrier gas are joined together into the gas inlet orifice part 78. The gas inlet 80 is fed into a gas volume extending over approximately the full height of the gas inlet orifice component 78. The gas inlet orifice component 78 forms, on its underside, a gas outlet opening similar to a plurality of sieves projecting toward the chamber 60 (not shown in FIG. 7). Through this gas outlet opening, the process gas and carrier gas can flow into the chamber 60.

In particular, in this embodiment, the gas flows horizontally through the chamber in a radial direction toward the peripheral region where the gas diverges vertically downwardly by the shield 74 (after vertical injection). Thereafter, the gas flows through the circular gas discharge channel 76, which is formed by the inner channel wall 82 and the outer channel wall 84. The gas flowing out of the gas discharge channel 76 flows into a common gas outlet conduit 86 surrounding the central axis of the process module 98. The previous line and the vacuum pump may be connected to the common gas outlet conduit 86 described above.

The channel inner wall 82 is also the outer wall of the substrate holder 70. The substrate holder 70 together form a body shaped like an inverted port. The flat outer wall (or "bottom") of the port forms a support surface for the substrate 72. The outer wall of the cylindrical port wall 82 forms the inner wall of the gas discharge outlet port 76. The channel outer wall 84 separated by the gap from the channel inner wall 82 is rigidly connected to the channel inner wall 82 and thus the substrate holder 70. For this firm connection, ribs or struts may be used (not shown).

The upper section 90 of the channel outer wall 84 (the "riser" of the step-like design) has a sealing ring 92 positioned radially outwardly with respect to the shield when the substrate holder 70 is in the processing position ) Into the annular groove (114). In this upper section 90, the material thickness of the outer channel wall 84 is reduced in accordance with the designed-in step. The seal ring 92 forms an annular groove 114 through which the bottom of the outer channel wall 84 can open and into which the compartment 90 of the outer channel wall 84 can be introduced. Whereby a gas seal ring is formed between the chamber 60 and the gas space 94. The outer channel wall (of the deep flow annulus) also forms a sealing surface (gas diffusion flow) against the inner wall 96 of the gas outlet conduit 86. Thus, the gas flowing through the gas outlet conduit 86 can not reach into the gas space 94. When the substrate holder 70 is lowered from the working position to the loading position, the outer surface of the pipe-shaped outer channel wall 84 moves (within a small space) along the inner wall 96 of the gas outlet conduit 86 .

As shown, the ALD device may be symmetrical with respect to the central axis 98. A lifting pin 100 (operating through opening 102 in substrate holder 70) may also be provided. The substrate holder 70 is supported by a pedestal 104 and the chamber may have an uppermost portion 106.

7, the lift pins 100 are in a contracted state such that the substrate 72 rests on the contact points 108, 110. As shown in Fig. Figure 8 shows a substrate holder in a lower (loading / unloading) position within the reactor 60. In order to transfer the substrate 72 into / out of the reactor, the substrate may be elevated using a lift pin 100, which moves from the retracted position shown in FIG. 7 to the loading and unloading feed (Not shown) to a substrate support position supported by the lift pins at a position above the level at which the lift pins can occur. In this manner, substrates can be continuously loaded / unloaded into / from the reaction chamber.

An enlarged view of the sealing interface in which the compartment 90 of the outer channel wall 84 is inserted into the annular groove 114 of the sealing ring 92 is also shown in Fig.

Therefore, when the substrate holder is placed in the processing position, the upper section of the channel wall, which is tightly connected with the substrate holder, is inserted into the circular groove 114 of the circular sealing ring, which is itself covered by the shield. These circular shields 74 and seal rings 92 may be combined into a single piece-piece. The circular shield 74 forms a circumferential wall of the process chamber and extends vertically from the gas inlet orifice component 78 to the gas discharge channels enclosed by the interior 82 and exterior 84 walls of the gas discharge channel 76 , Wherein the inner wall is tightly connected to the substrate holder (70). When the substrate holder is lowered from the above-mentioned processing position where layer growth occurs on the substrate surface to the load / unload position, the clearance space between the individual process chambers is opened. In this loading and unloading position, the substrate holder lies below the crevice space. The substrate holder forms an opening for penetration of the lift pin. The lift pins are lifted by the lift mechanism and raise the substrate from the lower surface to separate the lift pins from the substrate holder. To perform load and unload operations, the reactor chamber forms a side slot opening through which the robotic arm can reach the reactor chamber. The substrate holder is carried by a lift shaft, which can move the substrate holder vertically as described above.

Thus, a small, symmetrical flow (SVSF) device formed for a minimal ALD reaction volume with a symmetrical flow while minimizing chemical transfer to the reactor wall has been described. Although specific exemplary embodiments have been discussed, the present invention is not intended to be limited by these, and the present invention should be determined only by the following claims.

Claims (16)

delete delete A heater-susceptor (36) vertically movable between a machining position and a load / unload position and having a substrate support surface and a circumference;  An annular flow loop conduit (40) having an inner edge and an outer edge (44), wherein the input orifice (50) of the annular flow loop conduit (40) is flush with the substrate support surface of the heater- And the output orifice 42 of the annular flow annular conduit 40 is connected to a valve (not shown) which allows the wafer to be loaded / unloaded from the reaction chamber 34 when the heater-susceptor 36 is in a processing position Annular flow loop conduit (40) attached around the heater-susceptor (36) at the inner edge of the annular flow loop conduit (40) so as to be positioned below the heater-susceptor (36); And As the annular ring 46 attached to the lid 48 of the reaction chamber 34, (A) from the limited reaction space 32 of the reaction chamber 34 to the reaction chamber (not shown) on the wafer location on the substrate support surface of the heater-susceptor 36, The inner surface of the outer edge 44 of the annular flow-ring conduit 40 is connected to the annular collar 46 (in the form of a tongue-in-groove: TIG) (B) the upper section 90 of the outer edge 44 of the annular flow channel conduit 40 is positioned in a stepped manner to fit into a portion of the annular ring 46 And an annular ring (46). delete 4. An apparatus according to claim 3, wherein the annular flow ring conduit (40) is configured to direct the reaction gas effluent to a downstream pump orifice located off-axis with respect to the axi-centric center of the reaction chamber Wherein the reaction chamber device is configured to move the reaction chamber device. 6. The reaction chamber apparatus of claim 5, further comprising a downstream baffle (56) located between the output orifice (42) of the annular flow loop conduit (40) and the downstream pump (16). The reaction chamber apparatus of claim 3, further comprising a pump (16) connected to remove the gas stream from the lower chamber leading to the reaction chamber (34), the annular flow channel conduit (40) and the pump (16). delete delete 4. The reaction chamber apparatus of claim 3, wherein the output orifice (42) of the annular flow ring conduit (40) comprises a hole-like restrictor in the plane of the output orifice (42). delete The reaction chamber apparatus according to claim 3, wherein the inner edge of the reaction chamber lid (48) is curved. delete delete delete delete

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