Reactor casing assembly

Abstract

To provide a reactor casing assembly.SOLUTION: The present invention relates to a casing assembly for a reactor for epitaxial deposition of a semiconductor film on a substrate. The casing assembly includes an inner casing and an outer casing made of quartz and connected by at least two flanges made of engineering plastic. The present invention also relates to a reaction chamber enclosed by the casing assembly, and to a reactor using at least one of the reaction chambers.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to the field of epitaxial deposition of semiconductor films on substrates, and in particular to a casing assembly for a reaction chamber characterized by a double casing design. The present invention further relates to a reaction chamber and a reactor comprising the above-mentioned casing assembly. Additionally, the present invention relates to the field of depositing silicon carbide and gallium nitride films onto semiconductor substrates in hot-wall cross-flow homoepitaxial or heteroepitaxial reactors, although not exclusively. [Background technology]

[0002] Semiconductor films produced by epitaxial growth, also known as epilayers, are formed by deposition in a reaction chamber of a reactor. The deposited material may be the same as the substrate or may contain a different semiconductor with specific desired qualities. Epitaxial techniques control the crystalline structure formed on the substrate and improve the epilayer surface characteristics, making it suitable for the fabrication of highly complex microprocessors and memory devices.

[0003] Typically, the reaction chamber is heated to a desired temperature prior to film deposition, and the temperature is then maintained substantially constant throughout the deposition process. To this end, an isolation system is used to reduce the energy required to achieve and maintain the nominal temperature of the deposition process.

[0004] Epitaxial growth equipment for the silicon (Si), silicon germanium (SiGe), silicon carbide (SiC), or gallium nitride (GaN) industries may include hot-wall reaction chambers, where the walls are actively heated and temperatures can reach 1800°C in the region where the chemical vapor deposition process occurs.

[0005] These temperatures may be achieved, for example, via an induction heating system comprising an induction coil wound around the reaction chamber and connected to a power generation circuit. In this case, the chamber may comprise one or more heat-conducting elements, such as an assembly of one or more graphite parts. Indeed, graphite is characterized by a high sensitivity and will be effectively heated under an alternating electromagnetic field.

[0006] The above-mentioned chambers typically comprise an enclosure that may perform one or more of the following functions: (i) protecting the chamber from contamination; (ii) providing an enclosure for vacuum generation; (iii) preventing overheating of the chamber's ambient environment; and (iv) preventing leakage of process gases within the reactor.

[0007] The enclosure must avoid interaction and interference with the electromagnetic fields generated by the induction heating system and must be capable of withstanding temperatures up to 1000°C without structural damage and without releasing contaminants into the chamber.

[0008] To provide an enclosure with the above characteristics, quartz tubes, such as those described in U.S. Patent No. 5,629,492, are often used. The tubes may be hollow and may be cooled with an internal liquid flow. Cooling the tube allows the quartz to better withstand the heat radiating from the reaction chamber.

[0009] Quartz enclosures are typically fabricated by welding two concentric quartz tubes together and joining them at their edges, creating a fluid-tight cavity between the tubes for the flow and evacuation of cooling fluids, such as water, through a series of inlets and outlets protruding above the surface of the outer tube.

[0010] However, the above solutions are not ideal, and welding concentric quartz tubes often results in irreparable damage to the tubes, thereby affecting manufacturing costs. Overall, the welding process is primarily an artisanal process with inherently unpredictable yields, which substantially increases the manufacturing costs of quartz enclosures and creates serious procurement issues. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] US Patent Application Publication No. 2023 / 0313410 Summary of the Invention

[0012] An object of the present invention is to overcome the drawbacks of the prior art. More specifically, an object of the present invention is to provide a casing assembly for a reaction chamber, comprising: (i) a quartz inner casing and a quartz outer casing extending along a longitudinal direction (x), the inner casing being coaxially mounted relative to the outer casing and at least partially housed within the outer casing; and (ii) a first flange and a second flange made of an engineering plastic material connecting the inner casing and the outer casing and creating a liquid-tight cavity therebetween. The first flange comprises at least one inlet for directing a cooling fluid into the liquid-tight cavity, and either the first flange or the second flange comprises at least one outlet for discharging the cooling fluid from the liquid-tight cavity.

[0013] It is a further object of the present invention to provide a reaction chamber for epitaxial film deposition comprising the above-described casing assembly, and a reactor incorporating the above-described reaction chamber.

[0014] The above-mentioned main object is achieved by the invention as defined in the appended claims, which form an integral part of this specification.

[0015] It should be noted that the use of reference signs in the claims does not limit their scope: their sole purpose is to make the claims easier to understand.

[0016] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description of Example Embodiments of the Disclosure. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a simplified schematic diagram of a first embodiment of a casing assembly according to the present invention, where panel a) provides a side view of the casing assembly along the longitudinal direction (x), while panel b) provides a front view in a plane perpendicular thereto (yz). [Figure 2] FIG. 2 is a side view of a second embodiment of a casing assembly according to the present invention. [Figure 3] FIG. 10 is a side view of a third embodiment of a casing assembly according to the present invention. [Figure 4] FIG. 1 is a schematic diagram of a portion of a reaction chamber according to another embodiment of the present invention, where panel a) provides a lateral side view along the longitudinal direction (x) while panel b) provides a front view in a plane perpendicular thereto (yz). DETAILED DESCRIPTION OF THE INVENTION

[0018] It will be understood that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of the illustrated embodiments of the present disclosure.

[0019] DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS While certain specific embodiments and examples are disclosed below, it will be understood by those skilled in the art that the scope of the invention extends beyond the specifically disclosed embodiments and / or uses of the invention, and obvious variations and equivalents thereof. It is therefore not intended that the scope of the disclosed invention should be limited by the specific disclosed embodiments described below.

[0020] According to a first aspect, the present invention relates to a casing assembly for a reaction chamber suitable for epitaxial deposition of semiconductor films on substrates, including but not limited to deposition of Si, SiGe, SiC, or GaN films on semiconductor substrates of the same or different materials in a horizontal, hot-wall, single-wafer reaction chamber.

[0021] The casing assembly according to the invention comprises an inner casing and an outer casing made of quartz and extending in a horizontal plane along a longitudinal direction (x), the inner casing being mounted coaxially relative to the outer casing and being partially or completely housed within the latter.

[0022] The inner and outer casings are hollow and may have an essentially prismatic or cylindrical shape, preferably with a circular, oval, elliptical or rectangular cross section in a transverse plane (yz) defined as any plane perpendicular to the longitudinal direction (x).

[0023] The longitudinal lengths of the inner and outer casings may differ, for example the inner casing may extend beyond the edges of the outer casing.

[0024] The casing assembly provides an enclosure for the reaction chamber, which allows for the placement, access, and movement of the reaction chamber (and portions thereof) of the reaction and deposition unit, which is the core of the reactor where semiconductor substrates are typically placed on substrate holders to perform the actual epitaxial deposition process.

[0025] The sides of the inner and outer casings are open in cross section and may be closed or partially closed as described below, and are also referred to as the upstream and downstream sides, respectively, depending on the direction of injection / exhaust of precursor gases in the reaction and deposition units.

[0026] The inner and outer casings are connected to a first flange on one side and a second flange on the other side. These flanges create a closed, liquid-tight cavity between the inner surface of the outer casing and the outer surface of the inner casing. This liquid-tight cavity is suitable for flowing a cooling fluid, such as demineralized water, to prevent the quartz element from overheating. The cooling fluid may be under slight pressure, creating a pressure differential of approximately 0.3 bar to 1 bar relative to its surroundings. To counter this pressure, multiple pushers and / or spacers located on the outer surfaces of one or both flanges can prevent the flanges from displacing outward.

[0027] The first flange includes at least one inlet for directing cooling fluid into the liquid-tight cavity, and either the first flange or the second flange includes at least one outlet for discharging cooling fluid from the liquid-tight cavity.

[0028] The expression "liquid-tight cavity" should be understood to mean a cavity through which the cooling fluid can flow without leakage. The cavity is surrounded by the inner and outer casings and the first and second flanges. The cavity may be connected through one or more of its inlets to a piping system and / or a container that provides the cooling fluid, optionally under pressure. The cavity may also be connected through one or more of its outlets to a piping system and / or a container and / or a drain that allows the cooling fluid to be discharged after use. The cooling fluid may also follow a closed loop that allows continuous circulation of the liquid in and out of the cavity.

[0029] The number of inlets and outlets each may be kept below 20 to simplify manufacturing of the part and / or due to space constraints.

[0030] The first flange may be located either upstream or downstream of the reaction chamber (and the second flange may be located downstream or upstream) depending on the structural features of the reactor.

[0031] Both the first and second flanges are made of engineering plastic materials. These flanges reduce the risk of damaging the fragile quartz elements of the casing assembly compared to metal flanges. In addition, engineering plastic flanges are lighter than their metal counterparts and easier to handle and machine.

[0032] Additionally, the use of flanges avoids the problem of welding the inner and outer quartz casings together, thereby ensuring a faster, more efficient, and cost-effective manufacturing process.

[0033] According to one embodiment of the present invention, the first flange and the second flange may be advantageously selected from engineering plastic materials that are stable at temperatures above 70° C., such as polypropylene (PP-H), polyethylene (PE), chlorinated polyvinyl chloride (PVC-C), polyether ether ketone (PEEK), acetal copolymer (POM-C), and cast nylon (PA6-C or PA6-G), which allows the casing assembly to perform well, particularly in hot-wall reactors, for Si, SiGe, SiC, or GaN film deposition, especially for SiC or GaN, which require higher temperatures.

[0034] According to another embodiment, the casing assembly of the invention further comprises one or more pipes positioned in the liquid-tight cavity and extending in a straight or winding serpentine line along the longitudinal direction, the number of pipes being advantageously kept below 20 and being chosen to be the same as the number of inlets.

[0035] In this embodiment, each pipe is connected to an inlet and is provided with at least one opening for injecting cooling fluid into the liquid-tight cavity. The pipes allow for better distribution of the cooling fluid within the liquid-tight cavity. This is particularly true when the inlet and outlet are mounted on the same flange, and the pipes direct the cooling fluid longitudinally away from the outlet, allowing the cooling fluid to flow over a wider surface of the inner and outer casings. The number and spacing of the inlets and outlets in the cross-section also affect the distribution of the cooling fluid, as can be surmised by those skilled in the art.

[0036] Advantageously, the pipe may be provided with a plurality of openings, which may be of the same or different size and shape, located at different positions along its length in order to improve the spatial distribution of the cooling fluid and thus ensure a particularly uniform and effective cooling of the casing assembly.

[0037] If one or more inlets are located on the first flange and each is connected to one or more pipes, the first flange may be provided with a suitable conduit or recess for fitting and securing onto the side of the pipe. The second flange may also optionally be provided with a suitable recess for fitting onto the opposite side of the pipe, thereby providing additional structural support and reducing the risk of displacement. This may also aid in mounting the casing assembly.

[0038] In general, cooling of the casing assembly ensures better mechanical stability of the quartz elements and is particularly important for hot-wall reactors such as those described above for Si, SiGe, SiC, or GaN epitaxial deposition, especially SiC or GaN deposition. In the latter case, for example, the casing assembly may be exposed to temperatures of up to 1000°C due to the extremely high temperatures (1000-1800°C) of the adjacent reaction and deposition units, resulting in thermal irradiation of the casing assembly.

[0039] Many materials, such as quartz or heat-resistant glass or other vitreous materials, can be used for the pipes described above. However, the inventors have found that engineering plastics stable at temperatures above 70°C, such as polypropylene (PP-H), polyethylene (PE), chlorinated polyvinyl chloride (PVC-C), polyether ether ketone (PEEK), acetal copolymer (POM-C), and cast nylon (PA6-C or PA6-G), work particularly well in the practice of the present invention. Pipes made from these materials are easier to manufacture and handle than their quartz or glass counterparts.

[0040] According to another embodiment, the casing assembly of the present invention further comprises (i) a first O-ring and a second O-ring connecting the first flange and the second flange to the inner casing, respectively, and (ii) a third O-ring and a fourth O-ring connecting the first flange and the second flange to the outer casing, respectively.

[0041] These four O-rings are essential to prevent leakage of the cooling fluid from the liquid-tight cavity. The first and second flanges feature appropriate recesses for seating the four O-rings.

[0042] The inventors have observed that the above-mentioned O-rings can be successfully made of a fluorinated polymer, preferably a fluoroelastomer (FKM). However, it may be advantageous for the O-ring connecting the inner casing to the flange located on the downstream side of the casing assembly, i.e., either the first or second O-ring, to be made of a fully fluorinated polymer, preferably a perfluoroelastomer (FFKM). The downstream side of the inner casing is exposed to higher temperatures than the upstream side because it receives the flow of process gas from the reaction and deposition unit. Therefore, the O-ring connecting the inner casing to the downstream flange may benefit from the selection of a more robust material.

[0043] According to another embodiment of the invention, the sealing areas of the outer casing with the third O-ring and the fourth O-ring are both mounted either on the inner surface or on the outer surface of the outer casing.

[0044] "Sealing area" means the surface of the outer casing that comes into contact with the O-ring to ensure a seal between the parts. "Inner surface" of the outer casing means the longitudinal surface that faces towards the hollow interior space of the outer casing (conversely, the outer surface faces outwards). The same definition applies mutatis mutandis to the inner casing.

[0045] This embodiment makes it possible to simplify the manufacture of the outer casing: indeed, the required geometric tolerances of the outer casing are ensured by advantageously addressing the same surface of the casing (either internal or external) both upstream and downstream.

[0046] For installation purposes, it may be particularly advantageous to have the sealing region of the outer casing in which both the third O-ring and the fourth O-ring rest on the inner surface of the outer casing.

[0047] The outer casing may be made to slide toward the first (or second) flange above the corresponding O-ring, and the second (or first) flange may then be positioned to enclose the space, thereby facilitating manipulation of the casing assembly from within the reactor during installation, replacement, and maintenance operations, as this design reduces obstructions.

[0048] When pipe(s) connected to the inlet(s) are used, the O-ring sealing the outer casing is subject to different constraints depending on whether it is placed on (i) a flange with an inlet, or (ii) a flange without an inlet.

[0049] In the first case, the pipe, or any connecting conduit to the pipe, will pass through the flange below the O-ring, so the O-ring will always be positioned outward relative to the pipe, or any conduit connecting the pipe and inlet.

[0050] In the second case, the O-ring may be located behind the tip of the tube to save space. Therefore, the third and fourth O-rings, as well as the portions of the flange corresponding to the two O-rings, may have different diameters. In order for the two O-rings to properly seal the outer casing, the outer casing must in this case exhibit a variable cross-section.

[0051] The above-described configuration can be advantageously achieved by maintaining an essentially constant cross section of the outer casing throughout its length and locally varying its cross section corresponding to the flange with the inlet by creating a modification or "step".

[0052] There are a number of ways in which this localized modification of cross section can be achieved. To utilize standard commercially available cylindrical or parallelepiped quartz duct casing, it is possible to manufacture / procure the modified and standard structures separately and then permanently join them together.

[0053] To avoid damaging these quartz parts when they are fitted together, the inventors have found that laser welding or cold welding techniques work particularly well in the practice of the present invention.

[0054] The inner and / or outer casings are preferably made of optically clear quartz, otherwise they are likely to overheat due to the increased heat absorption properties of the opaque material.

[0055] The inventors have found that a casing assembly having an essentially cylindrical shape works well in the practice of the invention, its symmetry facilitating assembly of the parts.

[0056] Essentially cylindrical means that the shape may deviate locally from the ideal cylindrical shape for up to 15% of its length.

[0057] Those skilled in the art will understand that, individually, the casing assembly may require additional elements to function properly according to its purpose. For example, at least a third flange and a fourth flange may be used to connect the casing assembly, more specifically the inner casing, with other elements / regions upstream and downstream of the reaction chamber. Advantageously, these flanges may be made of stainless steel.

[0058] The casing assembly may also include additional O-rings, for example, to seal (a) the inlet on the first (or second) flange and, if present, (b) the pipe to the inlet.

[0059] In a second aspect, the present invention relates to a reaction chamber for epitaxial deposition of semiconductor films on substrates, comprising a casing assembly according to any one of the above-mentioned embodiments.

[0060] The reaction chamber also comprises a reaction and deposition unit in which the actual film deposition takes place, which comprises one or more structural / separation elements extending along its length and made of a sensitive material, i.e., a material with high sensitivity such as graphite, which can be effectively heated under an electromagnetic field.

[0061] The reaction and deposition unit may be provided with a receiving area configured to receive a substrate holder and may further comprise means for rotating the substrate holder and for measuring and controlling the angular velocity of the substrate holder. The reaction and deposition unit may optionally be specifically designed for horizontal hot-wall reactors for Si or SiGe, preferably SiC or GaN deposition. This may include elements made of SiC and / or parts coated with SiC or TaC.

[0062] The reaction chamber further comprises an insulation system configured to contain the reaction and deposition unit and minimize heat dissipation from the reaction and deposition unit. The insulation system may be made of a porous carbonaceous material, such as a carbon composite made from short-length carbon fibers, optionally interconnected or pressed together in a matrix. The insulation system may be comprised of one or more insulating shells.

[0063] The thermal insulation system may further comprise thermal insulation caps for enclosing the upstream and downstream sides of the reaction and deposition units, which may be provided with inlets and outlets to allow the introduction and evacuation of precursors and other working gases.

[0064] The casing assembly defines the perimeter of the reaction chamber and encloses the reaction and deposition unit and the thermal insulation system.

[0065] The casing assembly also has 10 chambers. -7 It may include connection to a vacuum generating system so that pressures as low as millibars can be reached.

[0066] The casing assembly, the reaction and deposition unit, and the insulation system may all be essentially cylindrical in shape.

[0067] In a third aspect, the present invention relates to a reactor for epitaxial deposition of a semiconductor film on a substrate.

[0068] The reactor comprises (i) at least one reaction chamber as described above, and (ii) an induction heating system configured to heat sensitive elements of the reaction and deposition units of the at least one reaction chamber.

[0069] The reactor according to the invention may advantageously be chosen for the homoepitaxial or heteroepitaxial deposition of Si or SiGe, preferably SiC or GaN, and may be chosen to be of the horizontal, single-wafer, hot-wall type. The reactor according to the invention is preferably a horizontal, cross-flow, hot-wall, epitaxial reactor for the deposition of silicon carbide.

[0070] It will be understood that a reactor according to the present invention will include many other elements typically required for its operation.

[0071] For example, the reactor will include a gas panel for controlling the delivery of process and working gases through an appropriate assembly of gas pipes and gas liners, including precursor and cooling gases for the reaction chamber, and gases for rotating the substrate holder and / or for purging the chamber to remove residue after use.

[0072] The reactor will generally be equipped with systems for exhaust gas evacuation and for controlling the rotation speed of the substrate holder. The reactor will also typically include a system for vacuum generation, and water lines and a demineralized water tank for cooling the casing assembly.

[0073] The examples presented below are not intended to be actual representations of any particular materials, structures, or devices, but merely idealized representations used to describe embodiments of the present disclosure. Specifically, they are not intended to otherwise limit the scope of aspects and implementations in any way. Indeed, for purposes of brevity, conventional manufacturing, association, preparation, and other functional aspects of systems may not be described in detail. Furthermore, connecting lines shown in the various figures are intended to represent example functional relationships and / or physical couplings between the various elements. Many alternative or additional functional relationships or physical connections may exist in an actual system and / or may not be present in some embodiments.

[0074] While certain specific embodiments and examples are disclosed below, it will be understood by those skilled in the art that the scope of the invention extends beyond the specifically disclosed embodiments and / or uses of the invention, and obvious variations and equivalents thereof. It is therefore not intended that the scope of the disclosed invention should be limited by the specific disclosed embodiments described below.

[0075] Figure 1 shows a simplified schematic diagram of one embodiment of a casing assembly (10) according to the present invention, providing a) a side view along the longitudinal direction (x) and b) a front view in a plane (yz) perpendicular to (x).

[0076] Specifically, panel a) shows a casing assembly (10) made of quartz and comprising an inner casing (100) and an outer casing (150) connected via a first flange (200) and a second flange (250). In this example, the sides of the outer casing abut against the first and second flanges, while the inner casing is longer and extends beyond them. Both the inner and outer casings are hollow and have an essentially cylindrical shape. The first flange comprises two inlets (300) for injecting a cooling fluid, such as demineralized water, into the liquid-tight cavity.

[0077] Each inlet is connected to a pipe (310) having an open end, i.e., an opening (315) at its tip, which is located adjacent to the second flange, so that the cooling fluid expands correspondingly to the second flange and flows back toward the first flange, where two outlets (350) are located (only one of which is visible in this view).

[0078] The inlet and the pipe may be connected longitudinally via a short conduit fabricated in the flange, and the pipe may be partially placed within this conduit.

[0079] The first and second flanges are preferably made of an engineering plastic that is stable above 70°C and may be located either upstream or downstream of the flow of precursor gas. The pipe may also advantageously be made of an engineering plastic with similar properties.

[0080] Panel b) shows the same casing assembly (10) of panel a) in cross section (yz) as seen from the front. This view illustrates the circular cross-section of both the inner and outer casings (100, 150) and the first flange (200). The inlet (300) and outlet (350) are located on the first flange. Conduits (301, 351) connect the inlet to a pipe (not shown) and the outlet to a liquid-tight cavity, respectively, so that the cooling liquid can be drained after use. The conduits are short longitudinal channels manufactured in the flanges. They connect the inlet to a pipe, the latter optionally inserted partially into said conduit for its entire length or a section thereof.

[0081] Generally, when the inlets and outlets are located on one and the same flange, it is convenient to alternate them radially. In both panels a) and b), the thicknesses of the inner and outer casings, the pipes, and the inlets and outlets are not shown.

[0082] Figure 2 provides a simplified side view of one embodiment of the casing assembly (10) of the present invention along a longitudinal direction (x) perpendicular to the transverse plane (yz). First and second flanges (200, 250) connect the inner and outer casings (100, 150), which are two quartz tubes. The flanges are made of polypropylene.

[0083] The flanges and pipes define a liquid-tight cavity between them. Two inlets (300) are located on the first flange and two outlets (350) are located on the second flange (one not shown). Generally, a person skilled in the art will adapt the number of connections to correspond to the size of the assembly and the temperatures reached during operation.

[0084] The inlet is configured to inject a cooling fluid into the fluid-tight cavity, where the fluid may expand to reach an outlet on the opposite side of the outer casing for discharge.

[0085] At least two stainless steel flanges (600, 650) are located on the sides of the inner casing (100). The stainless steel flanges may have a ring-like shape. They are used to separate chambers or to connect the casing assembly to other elements located upstream and downstream of the reaction chamber, such as enclosed areas or drums used to perform specific operations.

[0086] A plurality of pushers (700) are used to counter the pressure exerted on the first and second flanges by the cooling fluid within the cavity.

[0087] In general, however, one or more pushers may be used on the first flange and / or the second flange to counteract pressure exerted thereon by the cooling fluid within the cavity. For example, the inner casing and outer casing may be pressed against either the first flange or the second flange, and one or more pushers may be used to counteract pressure against the other flange, thereby avoiding the need to use pushers on both ends of the casing.

[0088] At least four O-rings (410, 420, 430, 440) are used. The first O-ring (410) and the second O-ring (420) connect the first flange and the second flange with the inner casing, respectively. They are positioned in suitable grooves or recesses made in the flanges, and the sealing area on the inner casing is located on its outer surface.

[0089] A third O-ring (430) and a fourth O-ring (440) connect the first flange and the second flange to the outer casing, respectively. Both are positioned in appropriate grooves or recesses made in the flanges. However, the sealing area of the third O-ring on the outer casing is located on its outer surface, while the sealing area of the fourth O-ring on the outer casing is located on the outer surface of the outer casing.

[0090] Note that the second flange features a variable cross section in transverse cross section, here represented by a "step" that is partially housed within the outer casing and retains the fourth O-ring.

[0091] This embodiment allows the use of two standard cylindrical tubes for both the inner and outer casings, but geometric tolerances on the outer casing must be met on the opposing surfaces of the casings to accommodate the sealing areas on the outer and inner surfaces of the outer casing, facing the third and fourth O-rings, respectively.

[0092] FIG. 3 provides a schematic illustration of another embodiment of the present invention according to the same side view and frame of reference as FIG. 2, with like numerals corresponding to like functional features.

[0093] In this embodiment, the inner and outer casings (100, 150) are two coaxial quartz tubes of different lengths. Two flanges (200, 250) resting on the sides of the outer casing create a fluid-tight space between the tubes. The flanges are made of cast nylon, highlighted here with a crisscross pattern. They have a variable cross section in cross section, and both feature a "step" in the longitudinal direction. The outer casing also features a variable cross section, exhibiting a "step" corresponding to the first flange, allowing portions of both the first and second flanges to be covered by the outer casing on both sides.

[0094] The aforementioned "step" locally increases the cross section of the outer casing, which can be adapted to wrap precisely around the abutting portion of the first flange.

[0095] Two inlets (300) and two outlets (350) are mounted on the first flange (200). Each inlet is connected to a pipe (310) provided with openings (315) spaced apart along its longitudinal direction (x). The pipe abuts the second flange (250) and is housed in a suitable recess or receptacle located thereon.

[0096] A first O-ring (410) and a second O-ring (420) respectively connect the first flange and the second flange with the inner casing, which is a cylindrical tube. The O-rings are positioned in suitable grooves or recesses made in the flanges, and the sealing area of the inner casing with the first O-ring and the second O-ring is located on its outer surface.

[0097] The third O-ring (430) and the fourth O-ring (440) connect the first flange and the second flange to the outer casing, respectively. Both are positioned in suitable grooves or recesses manufactured in the flanges, and the sealing areas of the outer casing with the third O-ring and the fourth O-ring are located on its inner surface. Therefore, only the inner surface of the outer casing must comply with the geometric tolerances required to ensure a seal.

[0098] Figure 4 shows a schematic representation of a reaction chamber (500) according to one embodiment of the present invention. Panel a) provides a side view along the longitudinal direction (x), and panel b) provides a simplified view in the transverse plane (yz), using the same reference frame as in Figure 1.

[0099] The reaction chamber comprises a casing assembly enclosing a reaction and deposition unit (510) with a receiving area (515) for a substrate holder. In panel b), the reaction and deposition unit is highlighted in grey for clarity. It contains graphite and SiC elements. The former has a half-moon shape and is suitable for being heated via induction means for the deposition of SiC.

[0100] Alternatively, the reaction and deposition unit may advantageously comprise a graphite cylinder having a removable box-shaped graphite part provided with a receiving area for a substrate holder.

[0101] The reaction and deposition unit illustrated here is surrounded by an insulating system. The latter comprises at least two insulating shells (551, 552). Panel a) shows two additional insulating caps (575), which are not included in panel b) for clarity.

[0102] The reaction and deposition unit and the thermal insulation system are enclosed by a casing assembly according to one embodiment of the present invention.

[0103] The casing assembly comprises an inner casing (100), an outer casing (150), first and second flanges (200, 250), a plurality of inlets (300), and a plurality of outlets (350). Each inlet has a plurality of openings (315) and is connected to a pipe (310) that abuts the inside of the second flange.

[0104] The induction heating system comprises a coil (1100) wound around the casing and connected to a generator. The coil is not part of the reaction chamber and is therefore shown schematically with a dotted line. The coil is configured to heat the reaction and deposition unit to temperatures up to 1800°C.

[0105] It will be understood that the configurations and / or approaches described in this disclosure are exemplary in nature, and that these specific embodiments or examples are not to be construed in a limiting sense, as numerous variations are possible. The specific routines or methods described in this disclosure may represent one or more of any number of process strategies. As such, the various illustrated operations may be performed in the order illustrated, in other orders, or omitted in some cases.

[0106] In this application, when used both in the specification and in the claims, the word "comprise" and variations thereof, such as "comprising" and "comprises", do not exclude the presence of other additional elements, components or steps.

[0107] The subject matter of this disclosure includes all novel and non-obvious combinations and subcombinations of the various processes, systems, and configurations, and other features, functions, operations and / or properties disclosed in this disclosure, as well as all equivalents thereof. [Explanation of symbols]

[0108] 10 Casing Assembly 100 Inner Casing 150 outer casing 200 First flange 250 Second flange 300 entrance 350 Exit

Claims

1. A casing assembly (10) for a reaction chamber suitable for epitaxial deposition of semiconductor films on substrates, comprising: an inner casing (100) and an outer casing (150) made of quartz and extending along a longitudinal direction (x), the inner casing (100) being placed coaxially with respect to the outer casing (150) and at least partially housed within the outer casing (150); a first flange (200) and a second flange (250) made of an engineering plastic material, connecting the inner casing (100) and the outer casing (150) and defining a liquid-tight cavity; Equipped with a casing assembly, wherein the first flange (200) or the second flange (250) comprises at least one inlet (300) for directing a cooling fluid into the liquid-tight cavity, and the first flange (200) or the second flange (250) comprises at least one outlet (350) for discharging the cooling fluid from the liquid-tight cavity.

2. 2. The casing assembly of claim 1, wherein the first flange (200) and the second flange (250) are made of an engineering plastic material that is stable at temperatures above 70°C, such as polypropylene, polyethylene, chlorinated polyvinyl chloride, polyether ether ketone, acetal copolymer, and cast nylon.

3. 3. The casing assembly of claim 1, further comprising one or more pipes (310) positioned within the liquid-tight cavity and extending along the longitudinal direction, each of the one or more pipes (310) connected to an inlet and provided with at least one opening (315).

4. The casing assembly of claim 3, wherein each of the one or more pipes (310) is provided with a plurality of openings disposed at different positions along the length.

5. 5. The casing assembly of claim 3 or 4, wherein each of the one or more pipes (310) is made of an engineering plastic material that is stable at temperatures above 70°C, such as polypropylene, polyethylene, chlorinated polyvinyl chloride, polyether ether ketone, acetal copolymer, and cast nylon.

6. Four O-rings, namely: a first O-ring (410) and a second O-ring (420) connecting the first flange (200) and the second flange (250) with the inner casing (100), respectively; a third O-ring (430) and a fourth O-ring (440) connecting the first flange (200) and the second flange (250) with the outer casing (150), respectively; The casing assembly of claim 1 , further comprising:

7. 7. The casing assembly of claim 6, wherein the first O-ring (410), the third O-ring (430), and the fourth O-ring (440) are made of a fluorinated polymer, and the second O-ring (420) is made of a fully fluorinated polymer, and the casing assembly is configured with the first flange (200) oriented upstream with respect to a flow of precursor gases for the epitaxial deposition of a semiconductor film on a substrate, and the second flange (250) oriented downstream with respect to the flow.

8. 8. The casing assembly of claim 6, wherein the sealing areas of the outer casing (150) having the third O-ring (430) and the fourth O-ring (440) are both on an inner surface of the outer casing (150).

9. A casing assembly according to any one of claims 1 to 8, wherein the inner casing (100) and the outer casing (150) have an essentially cylindrical shape.

10. A reaction chamber (500) for epitaxial deposition of a semiconductor film on a substrate, comprising: a reaction and deposition unit (510) extending along a longitudinal direction (x) and comprising one or more structural elements made of a sensitive material, the reaction and deposition unit being provided with a receiving area (515) configured to receive a substrate holder; an insulating system including one or more insulating shells (551, 552) enclosing said reaction and deposition units; a casing assembly (10) according to any one of claims 1 to 9, enclosing both the reaction and deposition unit and the thermal insulation system; A reaction chamber comprising:

11. A reactor (1000) for epitaxial deposition of a semiconductor film on a substrate, comprising: At least one reaction chamber (500) according to claim 10; at least one induction heating system (1100) configured to heat sensitive elements of said reaction and deposition unit (510) of at least one said reaction chamber (500); A reactor comprising:

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