Method and apparatus for servicing silicon deposition chamber using non-reactive gas-filled maintenance enclosure

Abstract: A process and apparatus is disclosed for providing access to the interior of a vacuum deposition chamber in a vacuum deposition apparatus (10) without exposing residues, such as chlorosilane residues, within the chamber to moisture and/or oxygen-containing gases. The process comprises first placing over the upper surface of the vacuum deposition apparatus (10) an enclosure (40) which has a bottom opening large enough to completely cover the top opening to the chamber, and which is capable of being filled with one or more non-reactive gases. One or more non-reactive gases are then flowed into the enclosure (40) to purge moisture and/or oxygen-containing gases from the enclosure. After the enclosure (40) has been mounted on the apparatus (10) and purged by the flow of non-reactive gases therein, the vacuum deposition chamber may be opened, while continuing the flow of non-reactive gases into the enclosure (40). After servicing, the vacuum deposition chamber may be resealed, the flow of non-reactive gases shut off, and the enclosure (40) then removed from the apparatus (10). In a preferred embodiment, the flow of non-reactive gases into the enclosure (40) is positioned to flow down from the top of the enclosure (40) at a right angle to openings (44) in the sidewall (43) of the enclosure (40) provided for accessing the vacuum deposition chamber, to thereby provide a gas curtain of non-reactive gas flow across the openings (44) to inhibit ingress of moisture and/or oxygen-containing gases, as well as particulate impurities, into the enclosure (40).

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a process and apparatus for servicing apparatus used in the processing of semiconductor wafers. More particularly, this invention relates to a process and apparatus which is useful in the cleaning of a reactor chamber used for the deposition of epitaxial silicon on a silicon wafer. 2. Description of the Related Art In the deposition of an epitaxial layer of silicon on a silicon semiconductor wafer by chemical vapor deposition (CVD) in a vacuum deposition chamber, using chlorosilane gas, various chlorosilane polymer byproducts or residues form in the deposition chamber. When the deposition chamber is subsequently opened to the atmosphere for servicing, moisture and/or oxygen-containing gases can enter the chamber and react with such chlorosilane polymeric residues to form chlorosiloxane polymers, which can result in the release of significant amounts of corrosive HCl gas and a powdery material which sometimes ignites. Control, or preferably elimination, of such a reaction of moisture or oxygen with chlorosilane residues accumulated in a vacuum deposition chamber of semiconductor wafer processing apparatus is, therefore, important for safety, reliability, and particle defect reduction. One previous approach to the solution of this problem has been to use exhaust systems to ventilate the area around the vacuum deposition chamber so that when the chamber was opened and exposed to moisture and/or oxygen-containing gases, the corrosive and inflammable gaseous byproducts, generated during such exposure, could be removed as they were formed. While such an approach reduced at least some of the deleterious effects of such chlorosiloxane formation, it would be more desirable if the reaction itself of the chlorosilane with moisture and/or oxygen to form chlorosiloxane could be completely suppressed or eliminated. Furthermore, JP-A-62 104 036 discloses a semiconductor treatment apparatus which has a system of chambers. In particular, the apparatus comprises an inert gas purging chamber; a first supplier for introducing inert gas into the purging chamber; an auxiliary chamber connected to the purging chamber; a first gate door for shutting-off the purging chamber and the auxiliary chamber; a first exhaust for exhausting gas in the auxiliary chamber; a second supplier for introducing inert gas into the auxiliary chamber; a second gate door for shutting-off the exhausting chamber from the atmosphere, which is located at the port opening for wafer boats of the auxiliary chamber; a third gate door for shutting-off the treating chamber connected with the inert gas purging chamber; a second exhaust for exhausting gas in the treating chamber; and a transporting mechanisms for transporting wafer boats transported to the auxiliary chamber to the treating chamber and vice versa. Thereby, mixing of air with inert gas in the purging chamber to which semiconductors e.g. wafers are transported can be completely avoided, preventing contamination of wafers and the treating chamber. SUMMARY OF THE INVENTION The invention is defined in claims 1 and 7, respectively. Particular embodiments of the invention are set out in the dependent claims 2 to 6 and 8 to 12, respectively. In particular, the present invention comprises a process and apparatus by which the formation of chlorosiloxane from accumulated chlorosilane residues, and the resultant formation of byproducts which may be corrosive and inflammatory, may be completely suppressed or eliminated. In accordance with the invention, an enclosure is fitted over the deposition chamber and then purged with one or more non-reactive gases, all prior to opening the chamber. The deposition chamber is then opened, while this enclosure is in place, and any required maintenance is then carried out in the deposition chamber while continuing to flow such non-reactive gas into the enclosure. Any components which need to be removed from the opened deposition chamber, e.g., a susceptor or showerhead, may be inserted into a sealed vessel, prior to removal of the component from the enclosure, for transportation to a remote facility such as a cleaning facility where any such accumulated chlorosilane residues may then be removed from the component. The following description and accompanying drawings will serve to further illustrate the invention. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a flow sheet, illustrating the process of the invention. Figure 2 is a side view of a prior art vacuum deposition apparatus prior to fitting the enclosure of the invention onto the apparatus, and prior to opening the vacuum deposition chamber. Figure 2A is a fragmentary top view of a portion of the prior art apparatus of Figure 2, showing the top plate and underlying quartz window of the vacuum deposition chamber bolted in place prior to opening the chamber. Figure 3 is a side view of a portion of the apparatus shown in Figure 2, but with the enclosure of the invention fitted on the top surface of the apparatus over the vacuum deposition chamber in preparation for opening the chamber. Figure 4 is an isometric view of the enclosure of the invention used to provide an atmosphere of non-reactive gas over the top portion of the apparatus, showing the means for providing ingress and egress to the interior of the enclosure by a worker without admission of moisture or oxygen-containing gases into the enclosure. Figure 5 is an isometric view of the framework of the enclosure, including a portion of the gas distribution manifold used to provide a flow of non-reactive gas into the enclosure. Figure 6 is a top view of the gas distribution manifold for flowing the non-reactive gas into the enclosure. Figure 7 is a vertical side view of the enclosure mounted on the apparatus over the top of the vacuum deposition chamber with the cover of the enclosure partially removed to show the flow of non-reactive gas flowing downward from the manifold into the enclosure from the top of the enclosure to provide a blanket of non-reactive gas flowing downwardly adjacent the opening into the enclosure to prevent ingress of outside gases into the enclosure. DETAILED DESCRIPTION OF THE INVENTION The invention provides a process and apparatus for providing access to the interior of a vacuum deposition chamber without exposing residues within the chamber to moisture and/or oxygen-containing gases by first placing, over the upper portion of an apparatus containing a vacuum deposition chamber, an enclosure capable of being filled with one or more gases. One or more non-reactive gases are then flowed into the enclosure to purge moisture and/or oxygen-containing gases from the enclosure. The vacuum deposition chamber cover may then be removed and the chamber opened, while continuing the flow of non-reactive gas/gases into the enclosure. After completion of the work within the vacuum deposition chamber, including removal of any components therein which may need cleaning or replacement, the vacuum deposition chamber cover is again secured over the chamber to seal the chamber. The flow of non-reactive gases into the enclosure may then be stopped and the enclosure removed from the apparatus. Referring now to the drawings, and in particular to Figure 2 and 2A, a vacuum deposition apparatus is generally illustrated at 2 which, in the illustrated embodiment, includes a vacuum deposition reactor apparatus 10, an interlock or loadlock 20 through which wafers may be moved in and out of deposition reactor 10 without breaking the vacuum in reactor 10, and heat lamp modules 30 and 34. The vacuum deposition chamber 11 itself within vacuum deposition reactor apparatus 10 is provided with quartz windows at the top and bottom of vacuum chamber 11. A portion of one of these quartz windows is shown at 12 in Figure 2A. Upper quartz window 12, and the corresponding quartz window at the bottom of vacuum chamber 11 permit chamber 11 and the contents therein to be radiantly heated via heat lamp modules 30 and 34, which are normally positioned immediately adjacent the windows, as shown by the position of heat lamp module 30 in Figure 2. Upper heat lamp module 34 is hinged at 36 to permit the module to be swung out of the way to permit removal of upper quartz window 12 for ingress into vacuum chamber 11. As shown in Figure 2A, quartz window 12 is secured to vacuum deposition reactor apparatus 10 via a ring 14 which is bolted to apparatus 10 via bolts 16. When it is desired to open chamber 11, for example to clean it or to change some of the components so that a different diameter wafer may be processed therein, in accordance with the invention, enclosure 40 is first mounted onto the top surface of apparatus 10, as shown in Figure 3. As more clearly shown in Figures 4 and 5, enclosure 40 comprises a hood-like structure which may, as shown in the illustrations, be generally rectangular in shape with perimeter dimensions generally just slightly smaller than that of vacuum deposition reactor apparatus 10, but slightly larger than the diameter of ring 14, to permit enclosure 40 to rest on the upper surface of apparatus 10 surrounding ring 14, with sufficient room to permit access to and removal of ring 14 with enclosure 40 in place. Enclosure 40 is most preferably formed of transparent sheet material 42, such as a transparent plastic to permit one working within enclosure 40 with his/her hands to visually monitor the work from outside enclosure 40. When enclosure 40 is formed from a transparent flexible plastic material, e.g., a polyethylene or vinyl material, a frame 50, formed of metal or wood, but preferably from a rigid plastic material, is used to provide a rigid support for transparent plastic material 42, as shown in Figure 5. Alternatively, if transparent sheet material 42 is formed in part of a rigid transparent material, as will be described below, rigid frame 50 may be either partially or totally eliminated. In any event, as shown in Figure 3, 4, and 7, at least a portion of transparent sheet material 42 is formed of a flexible plastic material which will permit insertion of one's hands into the enclosure to permit one to access the top of the vacuum deposition apparatus in order to open and service chamber 11. Such flexible plastic material, which preferably is also transparent, is usually provided on either one side 43 of enclosure 40, or on side 43 as well as the opposite side of enclosure 40 as well. As shown in Figures 3 and 4, preferably flexible plastic material 42 is cut at 45 into strips 44, providing a structure similar to that found at entrances to clean rooms in semiconductor wafer processing facilities. Alternatively, the flexible plastic material could be provided with a single slit on side 43 of enclosure 40, with the two halves of the slit provided with velcro or other fastening means to permit the opening formed by the slit to be wholly or partially closed. As shown in Figures 3 and 4, the cuts 45 in flexible plastic material 42 may extend only about half way up side 43, resulting in short strips 44. Alternatively, as shown in Figure 7, cuts 45' in flexible plastic material 42 may extend further up side 43 of enclosure 40 resulting in longer individual strips 44'. While the provision of longer length cuts 45' and strips 44', as illustrated in Figure 7, will facilitate access to the interior of enclosure 40, and to the top of deposition apparatus 10, shorter length strips 44 and cuts 45 will reduce the possibility of undesired gases or solid materials from entering enclosure 40. The use of such short strips 44 and cuts 45, as shown in Figure 3 and 4, would also permit the use of rigid transparent material on the upper portion of side 43 of enclosure 40, if desired. Referring to Figures 2 and 5, it will be noted that the bottom of frame 50 in Figure 5 is provided with what appears to be small appendages or members 52, and similar raised portions or members 54 are found on the top surface of apparatus 10. Such members 52 and 54 comprise fastening means capable of interlocking with one another, such as, for example, adhesive or velcro strips, which prevent or inhibit lateral movement of enclosure 40 with respect to vacuum deposition apparatus 10, once enclosure 40 has been placed on the top surface of apparatus 10 in preparation for opening vacuum deposition chamber 11. In accordance with the invention, to prevent moisture or oxygen-containing gases, such as air, from entering enclosure 40 and subsequently entering vacuum deposition chamber 11 after it is opened, one or more non-reactive gases, such as, for example, neon, argon, helium, or nitrogen, is flowed into enclosure 40 via conduit 60. A sufficient flow of such gas or gases into enclosure 40 is maintained to provide a slight positive pressure inside enclosure 40 to thereby prevent the entrance of undesirable gases and or solid particles into enclosure 40. Usually a flow of from about 20 standard liters per minute (slm) to about 40 slm of said non-reactive gas, per 28,32 dm 3 (cubic foot) of volume of said enclosure will comprise a sufficient flow to prevent entry of either moisture and/or oxygen-containing gases into said enclosure and into the open deposition chamber. In accordance with a preferred embodiment of the invention, the flow of such non-reactive gas or gases into enclosure 40 is preferably directed downward from the top of enclosure 40 from positions at the top of enclosure 40 adjacent the walls having openings therein, e.g., sidewall 43, so that a downwardly directed gas flow or gas curtain will be provided just inside the openings, e.g., just inside strips 44 or 44' and slits 45 or 45', through the flexible plastic. To provide such a gas flow, a gas manifold 62 is connected to gas inlet conduit 60, as shown in Figure 5. Manifold 62, in the illustrated embodiment, comprises a first cross conduit 64 which interconnects gas inlet conduit 60 with gas outlet conduits 66 and 68. Outlet conduits 66 and 68 are positioned at the top of enclosure 40 along the sides of enclosure 40, such as sidewall 43, which have openings therein. In this manner, non-reactive gases entering manifold 62 via conduit 60 flow into enclosure 40 through generally downwardly facing openings 70 in conduits 66 and 68, as best seen in Figure 7, to provide a downward flowing gas curtain just inside transparent flexible plastic strips 44'. Thus, in the practice of the invention, enclosure 40 is placed on the top surface of vacuum deposition apparatus 10 (after moving upper heat lamp module 34, if present, out of the way). The flow of non-reactive gas or gases into enclosure 40 is then commenced to purge moisture and/or oxygen-containing gases from enclosure 40. Cover ring 14 and upper quartz window 12 may then be removed, by reaching into enclosure 40 via strips 44 or 44' formed by slits 45 or 45' in flexible plastic material 42, to thereby open vacuum deposition chamber 11, while continuing the flow of one or more non-reactive gases into enclosure 40. If components are to be removed from chamber 11, such components may be placed in a special sealable container, which might comprise, in a simplified approach, a sealable plastic bag, to be removed from chamber 11, and then from enclosure 40, for transporting to a remote location, e.g., a vented enclosure, where the components may be cleaned or in other ways serviced. After completion of the work within the vacuum deposition chamber, quartz window 12 and cover ring 14 are resecured to vacuum deposition apparatus 10 to reseal chamber 11. The flow of non-reactive gas/gases into enclosure 40 may then be stopped and enclosure 40 may be removed from apparatus 10. In this manner chamber 11 may be serviced and components added, replaced, and/or removed from chamber 11 without exposing chlorosilane residues within chamber 11 to moisture and/or oxygen-containing gases capable of reacting with such chlorosilane residues to form corrosive HCl vapors and/or incendiary products within or adjacent to the vacuum deposition apparatus.

Claims: A process for providing access to the interior of a vacuum deposition chamber (11) in a vacuum deposition apparatus (10) without exposing residues within said chamber (11) to moisture and/or oxygen-containing gases which comprises: a) placing over the upper surface of said vacuum deposition apparatus (10) containing said vacuum deposition chamber (11) an enclosure (40) which has a bottom opening large enough to completely cover the top opening to said chamber (11), which has in one or more sidewalls (43) thereof opening means (44; 44') to permit access to said opening in said chamber (11), and which is capable of being filled with one or more non-reactive gases; b) flowing one or more non-reactive gases into said enclosure (40) to purge moisture and/or oxygen-containing gases from said enclosure (40); c) opening said vacuum deposition chamber (11) while continuing to flow said one or more non-reactive gases into said enclosure (40); d) closing said vacuum deposition chamber (11); e) shutting off said flow of non-reactive gases into said enclosure (40); and f) removing said enclosure (40) from said apparatus (10). The process of claim 1, including the further step of flowing said one or more non-reactive gases into said enclosure (40) downwardly from the top of the enclosure (40) at a right angle to one or more openings provided in a sidewall (43) of said enclosure (40) for accessing said vacuum deposition chamber (11), to thereby provide a gas curtain of non-reactive gas flow across said one or more openings to inhibit ingress of moisture and/or oxygen-containing gases, as well as particulate impurities, into said enclosure (40). The process of claim 1 or 2, wherein said step of flowing said one or more non-reactive gases into said enclosure (40) further comprises flowing one or more non-reactive gases selected from the group consisting of neon, argon, helium, nitrogen, and combinations thereof. The process of any of claims 1 to 3, wherein said step of flowing said one or more non-reactive gases into said enclosure (40) further comprises flowing said one or more non-reactive gases into said enclosure (40) at a flow rate of from about 20 slm (standard liters per minute) to about 40 slm per 28,32 dm 3 (cubic foot) of volume of said enclosure (40). The process of any of claims 1 to 4, including the further steps of placing one or more components in said chamber (11) into a gas-tight container and removing said container containing said one or more components from said chamber (11) and said enclosure (40), to thereby avoid exposure of the surfaces of said component to moisture and/or oxygen-containing gases while said component is being removed from said chamber (11) and from said enclosure (40). The process of any of claims 1 to 5, including the further step of securing a bottom surface of said enclosure (40) to said upper surface of said vacuum deposition apparatus (10) to inhibit said enclosure (40) from moving off said upper surface of said vacuum deposition apparatus (10) while said chamber (11) is being serviced. Apparatus for providing access to the interior of a vacuum deposition chamber (11) in a vacuum deposition apparatus (10) for servicing through an opening normally covered by a cover on said chamber (11) without exposing residues within said chamber (11) to moisture and/or oxygen-containing gases which comprises: a) a removable enclosure (40) capable of being temporarily placed over the upper surface of said vacuum deposition apparatus (10) containing said vacuum deposition chamber (11) to permit servicing of the interior of said vacuum deposition chamber (11), said enclosure (40) having a bottom opening large enough to completely cover said cover on said chamber (11), said enclosure (40) being capable of being filled with one or more non-reactive gases flowed into said enclosure (40) to purge moisture and/or oxygen-containing gases from said enclosure (40); b) opening means (44; 44') formed in one or more sidewalls (43) of said enclosure (40) to permit access to said opening in said chamber (11); and c) means (62) for flowing said one or more non-reactive gases into said enclosure (40); to thereby prevent moisture and/or oxygen-containing gases from entering said enclosure (40), whereby such undesirable gases will be excluded from contact with residues within said vacuum deposition chamber (11) when said cover is removed to access said chamber (11) for servicing through said opening in said chamber while said enclosure (40) covers said opening to said chamber (11). The apparatus of claim 7, wherein said opening means formed in one or more sidewalls of said enclosure (40) comprises a plurality of vertical strips (44; 44') which extend to said bottom opening of said enclosure (40). The apparatus of claim 8, wherein said vertical strips (44') extend from a point adjacent the top of said sidewall (43) of said enclosure (40) to said bottom opening of said enclosure (40). The apparatus of claim 8, wherein said vertical strips (44) extend downwardly to said bottom opening of said enclosure (40) from a point about midway between the top of said sidewall (43) of said enclosure (40) and said bottom opening of said enclosure (40). The apparatus of any of claims 7 to 10, wherein at least a portion of said enclosure (40) is covered with transparent material. The apparatus of any of claims 7 to 11, which further includes means (66, 68, 70) for flowing said one or more non-reactive gases into said enclosure (40) downwardly from the top of said enclosure (40) at a right angle to one or more openings provided in a sidewall (43) of said enclosure (40) for accessing said vacuum deposition chamber (11), to thereby provide a gas curtain of non-reactive gas flow across said one or more enclosure sidewall openings to inhibit ingress of moisture and/or oxygen-containing gases, as well as particulate impurities, into said enclosure (40).

Inventors: CARLSON DAVID K, RILEY NORMA B, CARLSON, DAVID K., RILEY, NORMA B.
Applicants: APPLIED MATERIALS INC, APPLIED MATERIALS, INC.
Application year: 1993
Main classification: C23C16
IPC codes: H01L21, C23C16