PLASMA ATOMIC LAYER DEPOSITION SYSTEM AND METHOD
20170016114 ยท 2017-01-19
Inventors
Cpc classification
C23C16/4412
CHEMISTRY; METALLURGY
C23C16/45536
CHEMISTRY; METALLURGY
C23C16/4583
CHEMISTRY; METALLURGY
C23C16/4404
CHEMISTRY; METALLURGY
C23C16/458
CHEMISTRY; METALLURGY
C23C16/45582
CHEMISTRY; METALLURGY
International classification
C23C16/455
CHEMISTRY; METALLURGY
Abstract
A gas deposition chamber includes a volume expanding top portion and a substantially constant volume cylindrical middle portion and optionally a volume reducing lower portion. An aerodynamically shaped substrate support chuck is disposed inside the gas deposition chamber with a substrate support surface positioned in the cylindrical middle portion. The top portion reduces gas flow velocity, the aerodynamic shape of the substrate support chuck reduces drag and promotes laminar flow over the substrate support surface, and the lower portion increases gas flow velocity after the substrate support surface. The gas deposition chamber is configurable to 200 mm diameter semiconductor wafers using ALD and or PALD coating cycles. A coating method includes expanding process gases inside the deposition chamber prior to the process gas reaching a substrate surface. The method further includes compressing the process gases inside the deposition chamber after the process gas has flowed passed the substrate being coated.
Claims
1. A method for coating a substrate with a solid material layer comprising the steps of: supporting the substrate on substrate support surface disposed in a substantially constant volume middle portion of a hollow gas deposition volume; introducing a first process gas into a volume expanding top portion of the hollow gas deposition volume and allowing the first process gas to expand in volume prior to impinging surfaces of the substrate; drawing the process gas out of the hollow deposition chamber through a exit port wherein the exit port is positioned opposed to the volume expanding top portion of the hollow gas deposition volume; removing substantially all of the first process gas from the hollow gas deposition volume while delivering an flow of inert gas into the hollow gas deposition volume; introducing a second process gas into the volume expanding top portion of the hollow gas deposition volume and allowing the second process gas to expand in volume prior to impinging surfaces of the substrate; and, removing substantially all of the second process gas from the hollow gas deposition volume while delivering a flow of inert gas into the hollow gas deposition volume.
2. The method of claim 1 wherein one of the first and the second process gases comprises a charged plasma gas.
3. The method of claim 2 wherein another of the first and the second process gases comprises a precursor gas.
4. The method of claim 3 wherein the hollow gas deposition volume further comprising a volume reducing bottom portion reducing the volume of the hollow deposition chamber between the substantially constant volume middle portion and the exit port further comprising step of reducing the volume of each of the first and the second process gasses as they pass between the substrate support surface and the exit port.
5. The method of claim 4 further comprising the step of preventing eddy current formation proximate to the substrate support surface by forming the substrate surface on a drag reducing aerodynamically shaped substrate support chuck.
Description
5. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] The features of the present invention will best be understood from a detailed description of the invention and a preferred embodiment thereof selected for the purposes of illustration and shown in the accompanying drawings in which:
[0025]
[0026]
[0027]
[0028]
[0029]
[0030]
[0031]
[0032]
[0033]
[0034]
[0035]
[0036]
[0037]
[0038]
[0039]
[0040]
[0041]
[0042]
[0043]
[0044]
[0045]
[0046]
6. LISTING OF ITEM NUMBERS
[0047]
TABLE-US-00001 100 Conventional thermal ALD system 110 Gas deposition chamber 120 Closable lid 130 System cabinet 1000 Load lock Configuration 1010 Plasma Source 1020 Gas cabinet 1030 Precursor Port 1040 Reaction (or Gas Deposition) Chamber 1050 Load Port 1060 Gate Valve 1070 Load lock chamber 1080 Transport Arm 1090 Isolation Valve 1100 Turbo Vacuum Pump 1110 Mag-Lev Turbo Vacuum Pump 1120 Roughing Vacuum Pump 1130 System Control Module 1140 Transport Mechanism 1150 Isolation Valve 1160 Pressure Gauge 1190 Top Vent 1200 Trap Assembly 2010 Plasma gas Port 2070 Substrate Holder 2080 Heated Chuck 2100 Plasma source flange 2140 Purge gas conduit 2150 Purge gas conduit 2160 Plasma port 3010 Load port aperture 3020 Load lock gate 3035 Circular Flange 3045 Transport Arm Inner Rod 3050 Transport Arm Outer Casing 3055 Load port aperture 3060 Load Port Shield 3070 Exit port) 5000 Gas Deposition Chamber 5010 Pressure Gauge 5015 Exit port 5020 Trap assembly 5025 Isolation valve 5030 Conical portion 5060 Trap exit port 5080 Hollow gas deposition volume 5090 Heated Chuck 5100 Precursor Gas Port 5105 External chamber wall 5110 Plasma exciter tube 5115 Cylindrical middle portion 5120 Plasma Source 5125 Top circular aperture 5130 Plasma source flange 5135 Substrate load aperture 5140 Manual load Port 5145 Load port gate 5155 Opposing circular flanges 5165 Radial axis 5175 Purge Gas Conduit 6010 Heating coils 6015 Substrate support surface 6020 reflective thermal baffles 6050 Circular top plate 6090 Hemispherical Outer shell 6100 Hollow tubes 7020 Top aperture 7030 Precursor Gas Port 7080 Hyperboloid mid-portion 7085 volume reducing lower portion 7090 Substrate support chuck 7095 Bottom circular aperture 8000 Gas deposition chamber second embodiment 8100 Precursor port 8105 Top portion 8110 Cylindrical ring middle portion 8115 Lower portion 8130 Plasma source flange 8140 Load port 8145 Substrate load port 8155 Trap flange 8160 Bottom circular aperture 8170 Vent tube 10000 Vacuum system schematic 9010 Vacuum gauge 9020 Pump exhaust 9030 Load lock purge port 9040 Pump purge 9050 Soft start valve 11000 Input gas panel schematic 12000 Front load lock configuration 13000 Front load tall gas cabinet configuration 13100 Manual load port 13110 Deposition chamber 14000 Front load side control configuration 14100 System controls 15000 Front load front control configuration 15100 Controller 16000 Cluster configuration 16100 Side Mounted Controller 16110 Load port 16120 Load lock port with gate valve 17000 Dual reaction chamber side controller configuration 17100 Side controller 17110 Load port gate 18000 Dual reaction chamber dual controller configuration 18010 Maintenance station display 18020 Operator station controls 18030 Operator station displays 18040 Maintenance station controls 18050 Emergency Shutoff Control 19000 System 19100 Load chamber 19110 Top access load port gate 19120 Back hinges 19130 Transport arm 20000 Gas deposition chamber 20005 Deposition chamber 20100 Outer wall 20110 Hollow deposition chamber 20115 Rectangular input aperture 20120 Plasma source flange 20130 Trap assembly flange 20140 Load port 20150 Load port aperture 20160 End flange 20170 Movable load port aperture cover 20180 Shuttle mechanism 20185 Purge line and valve 20190 Link 21000 Substrate support chuck 21100 Circular substrate support surface 21110 Hemispherical bottom portion 21120 Radius 21130 Substrate support lifting mechanism 21140 Substrate support element 21140 Brackets 21145 Top circular plate 21150 Circular substrate support element 21160 Circular recess 21170 Lift pins 21180 Lift plate 21200 Bottom wall of chamber housing 21210 Actuator plunger 21220 Transfer bracket 21230 Actuator 21240 Bellows 21270 Stationary rods
7. DESCRIPTION OF SOME EMBODIMENTS OF THE INVENTION
7.1 Overview
[0048] The present invention is a gas deposition system configured to deposit thin films onto substrate surfaces by several gas deposition processes. In particular, the gas deposition system of the present invention is configured as a plasma assisted or plasma enhanced atomic layer deposition (PALD) system, which includes a plasma source. The plasma source is suitable for delivering a plurality of different plasma excited gases into a gas deposition or reaction chamber. In addition, the gas deposition system of the present invention is configured as a conventional atomic layer deposition (ALD) system suitable for delivering a plurality of different ALD precursors or reactants into the gas deposition or reaction chamber. One advantage of the PALD aspect of the present invention is that a PALD gas deposition system can be used to deposit thin film material types that are not able to be deposited by the conventional or thermal ALD process and therefore not able to be deposited by conventional ALD coating systems.
[0049] In the exemplary embodiments described below, the gas deposition systems are configured to coat a top surface and side edge of a single circular semiconductor wafer up to 200 mm in diameter; however, several aspects of the present invention are independent of the type of substrate being coated. While the exemplary gas deposition systems described herein are configured to coat circular flat semiconductor substrates one at a time, various aspects of the present invention are independent of the shape or material of the substrate. In particular, the present invention uses a method of reducing the velocity of process gases delivered into the gas deposition chamber by expanding the volume of the process gases prior to the process gasses coming into contact with the surfaces being coated and these methods is usable in other gas deposition system configurations. Additionally, because the systems of the present invention utilize ALD and PALD coating processes, the present invention is capable of applying uniform coating layers to substantially flat surfaces as well as to complex shapes including those with micron scale high aspect ratio topographic features. Accordingly, the systems of the present invention are usable to coat three dimensional substrates such as formed metallic, plastic or ceramic elements including surgical tools, engine parts, electrical components and any other three dimensional element having surfaces to be coated as may be required. Moreover, the systems of the present invention, as described herein, allow every surface of the substrate that is exposed to deposition gases to be coated with a substantially uniform thin film layer thickness.
[0050] Several improvements of the system of the present invention as compared to conventional gas deposition systems relate to the shape of a gas deposition or reaction chamber shown in side cut away view in
[0051] Other improvements of the of the system of the present invention as compared to conventional gas deposition systems relate to the versatility of the manner in which gas combinations can be delivered into the gas deposition chamber to perform either conventional thermal ALD coating processes or plasma assisted or PALD coating processes. In addition, the system of the present invention can also perform chemical vapor deposition (CVD) coating process cycles by injecting at least two gases into the chamber simultaneously.
[0052] These and other aspects and advantages will become apparent when the description below is read in conjunction with the accompanying drawings.
7.2 Exemplary System Architecture
[0053]
[0054] A substrate to be coated or otherwise processed is loaded through the load port aperture (3010) onto a substrate holder (2070) which is initially stationed inside the load lock chamber (1070). The substrate holder (2070) is fixedly attached to a transport arm (1080) and movable from the load lock chamber (1070) into the gas deposition chamber (1040) by linear movement of the transport arm (1080). The transport arm (1080) is moved along a linear axis from the load lock chamber to the gas deposition chamber by a magnetic transducer (1140). Other means of actuating the transport arm, such as linear induction motors, hydraulic pistons, pneumatic rams, or the like, including a manual transport mechanism are also usable without deviating from the present invention. In addition, the transport arm (1080) and transducer (1140) are configured to lower the substrate holder into contact with a heated chuck once the substrate holder and substrate supported thereon are positioned in a coating position inside the gas deposition chamber. The lowering action and subsequent raising of the substrate holder to remove the substrate may be provided by lowering and raising the transducer (1140).
[0055] The load lock chamber (1070) and the gas deposition chamber (1040) are interconnected through a load port (1050). The load port (1050) comprises a rectangular conduit that extends between the spherical load lock chamber (1070) and the reaction chamber (1040). The load port (1050) is sized to pass a substrate supported on the substrate holder (2070) from the load lock chamber (1070) to the reaction chamber (1040). A gate valve (1060) is disposed in the load port (1050) between the load lock chamber (1070) and gas deposition chamber (1040). The gate valve (1060) serves to isolate the reaction chamber (1040) from the load lock chamber (1070). This prevents contaminates from entering the reaction chamber (1040) when the load lock chamber is open to the atmosphere. The closed gate valve (1060) is also used to maintain a vacuum pressure in the reaction chamber (1040) while the load lock chamber is opened to atmosphere while substrates are being loaded into or unloaded from the load lock chamber (1070). The transport arm (1080) moves the substrate holder (2070) and the substrate held thereon from the load lock chamber to the deposition chamber and positions the substrate is in a coating position within the gas deposition chamber (1040). As best viewed in
[0056] The gas deposition chamber (1040) comprises a chamber enclosure wall, described below, formed to enclose a hollow gas deposition chamber which is sized to receive substrates to be coated or processed therein and which is constructed as a chamber suitable for deep vacuum pump down. The gas deposition chamber (1040) includes four ports passing through the chamber enclosure wall. A plasma source flange (2100) is formed at a narrow top end of the gas deposition chamber (1040) and a plasma source (1010) or other high-energy input source is attached to the plasma source flange (2100) for delivering plasma gases into the gas deposition chamber (1040). A plasma port (2160) delivers plasma gases to the plasma source (1010) and the plasma port interfaces with a plasma exciter tube (5110) which excites the plasma gases passing there through and delivers the plasma gases into the gas deposition chamber (1040) through the plasma source flange (2100). A second port comprises a precursor port (1030) passing through the narrow top end of the gas deposition chamber (1040) for delivering precursor gases into the gas deposition chamber proximate to the plasma source flange (2100). The plasma port (2160) and the precursor port (1030) are both in fluid communication with a gas panel, which is housed inside a gas tight cabinet (1020) that includes a top vent (1190) for venting the gas cabinet to a safe venting area. A third port passing through the gas deposition chamber enclosure comprises a rectangular load port aperture (3055). The rectangular load port aperture (3055) is sized and shaped as required to transport the substrate holder (2070) and a substrate to be coated there through. A fourth port passing through the gas deposition chamber enclosure comprises an exit port formed by a circular aperture (3070) at a wider base portion of the gas deposition chamber (1040). The exit port (3070) interfaces with an ALD type trap assembly (1200) that attaches to the base of the gas deposition chamber (1040). The ALD type trap assembly (1200) is heated and reacts with precursor and or plasma gases in gas outflow exiting from the gas deposition chamber (1040) to remove any remaining precursor and or plasma gases from the outflow to thereby prevent precursor and or plasma gas contamination of down stream vacuum system elements. The trap assembly (1200) also supports a vacuum pressure gauge (1160) for monitoring the gas pressure in the trap assembly. The gas deposition chamber (1040) may also include other ports such as additional precursor ports, purge gas ports, gauge ports, electrical interface ports, and the like, as may be required. Each of the gas deposition chamber ports is constructed with high performance vacuum seals and other hardware as required to prevent precursor gases from leaking out or atmosphere from leaking in when the reaction chamber is drawn down to a deep vacuum. Accordingly, it is advantageous to limit the number of ports in the reaction chamber.
[0057] Generally, the gas deposition chamber of the load lock configuration (1000) is continuously maintained at a low vacuum pressure during operation and during substrate loading and unloading through the load port (1050). At start up, the roughing vacuum pump (1120) is used to draw the gas deposition chamber (1040) from atmospheric pressure down to less than 1 torr. Thereafter a magnetic bearing or (mag-lev) turbo vacuum pump (1110) is used to draw the gas deposition chamber (1040) down to an operating pressure, e.g. less than 100 torr. The gate valve (1060) serves to isolate the gas deposition chamber (1040) from the load lock chamber (1070). For example, the gate valve (1060) is closed before the load lock chamber is purged to atmospheric pressure for loading or unloading a substrate into the load lock chamber. This feature of the load locked gas deposition system (1000) is particularly advantageous because it reduces gas deposition cycle times. In particular, because the gas deposition chamber (1040) is isolated from the load lock chamber by the gate valve (1060), the deposition chamber (1040) remains at a vacuum pressure, e.g. less than 1 ton, during substrate load and unload cycles. This eliminates the need to use the roughing pump (1120) after each substrate is loaded into the deposition chamber (1040). Instead, each time a substrate is loaded into the gas deposition chamber (1040) or each time the gas deposition chamber is purged to remove a precursor gas between coating deposition cycles, the vacuum pressure in the gas deposition chamber can be pumped down using only the magnetic bearing or (mag-lev) turbo vacuum pump (1110). This makes the gas deposition chamber (1040) pump down a smaller adjustment to its vacuum pressure than would have to be made if the deposition chamber was exposed to the atmosphere. The small adjustments to the vacuum pressure inside the reaction chamber (1040) e.g. from less than 1 ton to less than 100 torr are shorter in duration as compared to pumping the deposition chamber down from atmospheric pressure. Thus, the load lock configuration (1000) can reduce the time required to coat each substrate by several minutes. In addition, the magnetic bearings of the turbo pump (1110) are used to gain increased pump velocity which is needed to produce lower vacuum pressures, e.g. down to less than 1 microtorr. As further shown in
[0058] Referring to
[0059] Referring to
[0060] To move a substrate from the load lock chamber (1070) to the gas deposition chamber (1040), the substrate holder (2070) is initially positioned in the load lock chamber (1070). The substrate holder is sized to receive a substrate to be coated thereon and to pass the substrate through the load port (1050). To place the substrate to be coated onto the substrate holder (2070), the load port gate valve (1060) is closed to isolate the gas deposition chamber (1040) from the load lock chamber and the load lock chamber is purged to equalize its internal pressure with the local atmospheric pressure. Thereafter a user or automatic substrate manipulator, not shown, opens the load lock chamber gate (3020), inserts a substrate through the load port aperture (3010), and places it onto the substrate holder (2070). Typically, semiconductor wafers are handled using wafer tweezers to pass the wafer through the load port aperture for loading or unloading the wafer onto the substrate holder (2070).
[0061] In the present example, the substrate holder (2070) holds a thin circular disk shaped semiconductor wafer having a diameter of up to 200 mm. The wafer is substantially centered on the substrate holder by a circular flange (3035) shown in
[0062] Referring now to
[0063] Referring now to
[0064] In the present example, the substrate holder (2070) comprises a solid thin disk formed from a unitary layer of metal, e.g. stainless steel or aluminum, with a high thermal conductivity for quick conduction of thermal energy from the heated chuck to the substrate. However, the highest substrate temperatures that will be required by the gas deposition processes also need to be considered when selecting the materials of substrate holder (2070) to ensure that deformation or melting of the substrate holder does not occur at high process temperatures. Similarly, the material of the arc shaped load port shield (3060) should be suitable for high temperature environments and may comprise stainless steel or aluminum. In a further aspect of the present invention, a bottom side of the substrate holder solid thin disk portion may be hollowed out in some areas, e.g. around the circumferential edge, to reduce material weight while still providing rapid thermal conduction from the heated chuck to the substrate. The substrate holder (2070) stays in the reaction chamber (1040) during processing and further serves to shield the horizontally disposed heated chuck substrate support surface to prevent material layers formed by the coating cycles being conducted in the gas deposition chamber from building up on the substrate support surface. The substrate holder (2070) also positions the substrate supported thereon in the coating position which is substantially centered over the horizontally disposed heated chuck substrate support surface and substantially coaxial with a substantially vertically disposed central axis of the gas deposition chamber and centered over heating elements disposed inside the heated chuck. When inserting or removing a substrate, the substrate holder (2070) is transported over the substrate support surface of the heated chuck without making contact with the heated chuck. However, once the substrate holder (2070) is in the coating position, it is lowered into contact with the heating chuck to remaining in contact with the heated chuck throughout the coating cycle. After coating, the substrate holder (2070) is then raised out of contact with the heated chuck for transport. In addition to reducing gas deposition chamber pump down time, the load lock configuration (1000) helps to prevent contaminants, such as water vapor, from getting into the gas deposition chamber (1040).
[0065] After the coating process is completed, the substrate is removed in reverse order of insertion by transporting the substrate support (2070) and substrate supported thereon back to the load lock chamber (1070), closing the load port gate valve (1060), purging the load lock chamber to atmosphere and removing the substrate through the lock port aperture (3010).
[0066] Referring now to
[0067] The gas deposition chamber (5000) extends along a substantially vertical central longitudinal axis (V) and comprises an external chamber wall (5105) formed to enclose a hollow gas deposition volume (5080) therein. The external chamber wall (5105) is open at top end thereof and forms a top circular aperture (5125) centered with respect to the axis (V). The chamber wall top end forms or is attached to a top or plasma source flange (5130) suitable for supporting a plasma source (5120) thereon and forming a vacuum seal with the plasma source (5120). In the present example, the top circular aperture (5125) is approximately 75 mm, (2.95 inches) in diameter.
[0068] The plasma source includes a plasma input port, (e.g. 2160 in
[0069] The plasma input port is in fluid communication with plasma gas supply containers housed in an input gas panel, shown schematically in
[0070] A precursor gas port (5100) passes through the external chamber wall (5105) proximate to the top circular aperture (5215). In the present example, the precursor gas port (5100) is not directed vertically downward but instead the precursor gas port (5100) is oriented approximately at a 45-degree angle with respect to the (V) axis to direct precursor gas input flow exiting therefrom vertically downward but not along the vertical axis (V). The precursor port (5100) is in fluid communication with the input gas panel (11000) shown schematically in
[0071] The external chamber wall (5105) is formed to surround a volume expanding top portion of the hollow the hollow gas deposition volume (5080). In the example embodiment shown in
[0072] The cylindrical middle portion (5115) of the external chamber wall is formed to surround a cylindrical middle volume centered with respect to the vertical axis (V). In the example embodiment of the chamber (5000), the cylindrical middle portion (5115) of the external chamber wall has a substantially constant internal diameter of approximately 300 mm, (11.8 inches) that is substantially coaxial with the axis (V). The cylindrical middle portion (5115) extends from the top portion to a circular exit aperture or exit port (5015) that is centered with respect to the vertical axis (V) and opposed to the top aperture (5125). A trap assembly (5020) interfaces with the exit port (5015) such that outflow from the hollow deposition volume (5080) exits through the trap assembly (5020). The trap assembly includes a conical portion (5030) that narrows in diameter to form a trap exit port (5060). The trap exit port (5060) is in fluid communication with the vacuum turbo pump (1100), which removes outflow from the hollow gas deposition volume (5080) and pumps the volume (5080) down to a desired vacuum pressure.
[0073] A heated chuck (5090) positioned inside the hollow gas deposition volume (5080) includes a substantially horizontally disposed substrate support surface (6015) for supporting a substrate thereon. A rectangular substrate load aperture (5135) extends through the middle portion of the external chamber wall (5105) opposed to the substrate support surface (6015). A substrate load port (5140) is attached to or integrally formed with the external chamber wall surrounding the substrate load aperture (5135) and provides a passageway for substrates to enter and exit the hollow chamber volume (5080).
[0074] The cylindrical middle portion (5115) and the trap assembly (5020) are attached together by opposing circular flanges (5155), with one circular flange being fixedly attached to or integrally formed with the cylindrical middle portion (5115) the other circular flange being fixedly attached to or integrally formed with the trap assembly (5020). The opposing circular flanges (5155) form a vacuum seal between the cylindrical middle portion (5115) and the trap assembly (5020) and are attach to a structural frame, not shown, to support the entire gas deposition chamber (5000) on the structural frame.
[0075] The trap assembly (5020) comprises a conventional ALD trap or filter such as the one disclosed in co-pending U.S. patent application Ser. No. 11/167,570, published as US Patent Publication No. 2006-0021573 by Monsma et al. entitled VAPOR DEPOSITION SYSTEMS AND METHODS, filed on Jun. 27, 2005, which is incorporated herein by reference in its entirety. The trap assembly (5020) includes a heated trap element formed with sufficient surface area to react with precursor and excited plasma gases passing through the trap assembly (5020) as they exit the hollow gas deposition volume (5080). In particular, the trap surface area may be heated to substantially the same temperature as the substrate being coated in order to cause the precursor or charged plasma gasses to react with the trap surface area and form the same material layers on the trap surface area as are being coated onto substrate surfaces by the coating process being carried out in the gas deposition chamber. Over time, material layers built up on the trap surface area may degrade trap performance so the trap element can be removed and replaced as required to maintain good trap performance.
[0076] Referring to
[0077] The external chamber wall (5105) includes a top portion that extends from the top circular aperture (5125) to a top edge of the cylindrical middle portion (5115). In the example embodiment of
[0078] The heated chuck (5090) is disposed with its circular substrate support surface (6015) substantially coaxial with the vertical (V) axis and substantially coplanar with or slightly vertically below the interface between the volume expanding top portion and the top edge of the cylindrical middle portion (5115). Accordingly, a substrate being coated is substantially horizontally disposed on the substrate support surface (6015) with its circular center sustainably coaxial with the (V) axis and with the surface being coated exposed to a gas flow that has been expanded in volume and reduced in velocity by flow through the volume expanding top portion. In particular, the volume expanding top portion is formed to reduce the velocity of gas flow as the gas flows from input port (5100) and or exciter tube (5110) to the substrate support surface (6015) disposed in the cylindrical middle portion (5115).
[0079] In the exemplary embodiment shown in
[0080] More generally, the shape of the hollow gas deposition volume (5080) as well as the position and shape of the heated chuck (5090) are configured to reduce aerodynamic drag or resistance to gas flow associated with a substrate supported on the substrate support surface (6015) and the heated chuck (5090). According to Bernoulli's equation, aerodynamic drag is proportional to the square of the gas flow velocity so any reduction in gas flow velocity proximate to the heated chuck (5090) serves to reduce the aerodynamic drag of the heated chuck (5090). According to the present invention, the velocity of gas flow exiting from the precursor port (5100) and or the exciter tube (5110) steadily decreases as the gas flow expands in volume along the gas deposition chamber top portion described above. Thus, the shape of the gas deposition volume (5080) and specifically the continuously increasing volume of the top portion of the external chamber wall (5105) from the top aperture (5125) to the cylindrical mid portion (5115) serve to decrease gas flow velocity and reduce aerodynamic drag caused by the heated chuck (5090). To further reduce aerodynamic drag or resistance to gas flow as it impinges on the heated chuck (5090) and flows around the heated chuck (5090) to the trap assembly (5020) the drag coefficient of the substrate support chuck (5090) support elements may also be reduced.
[0081] Referring to
[0082] The heated chuck (5090) further comprises a hemispherical outer shell (6090) that attaches to the circular top plate (6050) at a bottom circumferential edge thereof. The hemispherical outer shell (6090) is hollow and houses a plurality of electrical resistance heater coils (6010), or the like. The heater coils are positioned proximate to or formed integrally with the circular top plate (6050) or associated middle circular plates for heating the circular top plate (6050) and transferring thermal energy to a substrate supported on the substrate support surface (6015) or on a substrate holder (2070) in contact with the substrate support surface (6015). The electrical heaters may be opposed by reflective thermal baffles (6020) and or thermally insulating materials positioned to maintain the top circular plate (6050) at a desired operating temperature. The heated chuck (5090) may further comprise one or more temperature sensors positioned to detect local temperature and deliver a temperature signal to the system controller, (e.g. 1130 shown in
[0083] The heated chuck is supported within the hollow gas deposition volume (5080) by three hollow tubes (6100) that each pass through and are held in place between the opposing flanges (5155). Each hollow tube (6100) is fixedly attached to the outer shell (6090) and the three hollow tubes are disposed approximately 60 degrees apart around the circumference of the outer shell (6090). The hollow tubes (6100) serve as conduits for passing electrical wires through the outer shell (6090) and may also serve as fluid conduits as may be required. The use of the three hollow tubes (6100) to support the heated chuck (5090) reduces aerodynamic drag in the region between the hemispherical outer shell (6090) and the internal diameter of the cylindrical middle portion (5115) by providing a substantially open conduit for the gas to pass through as is flows around the heated chuck (5090).
[0084] The improved gas deposition chamber (5000) includes external heating elements surrounding the external chamber wall (5105) and a thermal insulation layer surrounding the external heating elements. These are shown in phantom in
[0085] Referring now to
[0086] A load port (8140) forms a substrate load port (8145) and a corresponding aperture, not shown, passing through the middle cylindrical ring portion (8110) for loading and unloading substrates into the gas deposition chamber (8000). The load port (8145) is substantially opposed to the substrate support surface provided by the substrate support chuck positioned inside into the gas deposition chamber (8000). The gas deposition lower portion (8115) is formed to reduce the internal chamber volume below the substrate support surface. More specifically, the lower portion (8115) is formed to more closely follow the contour of the substrate support chuck below the substrate support surface. The reduction of internal chamber volume below the substrate support surface serves to increase gas flow velocity below the substrate support surface and the increased gas velocity helps to reduce the time required for a given gas volume to flow through the gas deposition chamber (8000). Thus the shape of the lower portion (8115), which is formed to reduce the internal chamber volume below the substrate support surface, reduces gas deposition cycle times.
[0087]
[0088] The gas flow model uses a constant input volume of 100 Standard Cubic Centimeters per Minute (SCCM) through the input port (7030) and a constant input volume of 200 SCCM through the top aperture (7020). The resulting graphical plots shows a flow velocity entering the deposition chamber through the input port (7030) of approximately 3.0 Meters per Second (m/s) and a flow velocity entering the deposition chamber through the through the top aperture (7020) in the approximate range of 1.2 to 3.0 (m/s). The graphical plots further shows a gas flow impinging on the substrate support surface that has a substantially constant velocity of less than 0.3 m/s over the entire circular surface. The graphical plots further shows gas flow direction vectors indicated by arrowheads. The arrowheads show that gas impinging onto the substrate support surface substantially flows radially outward toward the circular peripheral edge of the substrate support surface and over the circular peripheral edge toward the bottom circular aperture (7095).
[0089] Moreover, the graphical plots shown in
[0090]
[0091] On the reaction chamber side, a second turbo vacuum pump (1110) is usable to pump down the reaction chamber (1040). A second vacuum gage (5010) is disposed between the second turbo vacuum pump (1110) and the deposition chamber (1040) for detecting and reporting gas pressure in the deposition chamber. A second isolation valve (5025) is disposed between the roughing pump (1120) and the second turbo vacuum pump (1110) to isolate the deposition chamber (1040) from the roughing pump. The roughing pump (1120) includes an exhaust port (9020) that is vented to a safe venting area and outflow from the reaction chamber (1040) is preferably vented to the exhaust port (9020). In addition, the deposition chamber includes a top aperture (2010) for attaching a plasma source to the deposition chamber (1040) and the plasma source may deliver charged or uncharged process or inert gases into the deposition chamber. In other embodiments, the top aperture is sealed if the system (10000) is configured without a plasma source. The vacuum system (10000) may also include one or more ports, e.g. (9030) in the load lock chamber, (9040) in the second turbo pump (1110), (9050) in the roughing pump (1120) and (2140) in the substrate load port, to deliver a purge gas into various portions of the vacuum system to increase gas pressure or to purge unwanted gases from the region being purged.
[0092] Referring now to
[0093] Generally the vacuum system (10000) and the gas input system s (11000) shown in
[0094] More generally, with respect to the reaction or deposition chambers of the present invention, the gas input system (11000) is configured to deliver a continuous flow of inert or purge gas through each of the process gas input lines associated with the deposition chamber. The continuous flow of inert gas serves as a carrier gas suitable for carrying process gases into the gas deposition chamber and serves to prevent process gases from entering the process gas input lines from the gas deposition chamber and possibly mixing in the gas input lines to coat internal surfaces of the gas input lines with solid layers. In addition, for each process gas input line or port, the gas input system (11000) is configured to select one process gas from a plurality of process gas supply containers in fluidic communication with the gas input line and to deliver the selected process gas into the input line. Process gases may be delivered in a continuous flow stream or in pulses controlled by opening and closing a gas pulse valve disposed between the input line and a process gas supply. In addition, the gas input system may deliver a continuous or a non-continuous flow of inert gases to various other lines and ports used to flush out or change the gas pressure in other regions of the gas deposition system as may be required.
[0095] The components of the exemplary gas deposition systems described above can be associated in various orientations and combinations so as to produce a variety of configurations, each with characteristics useful to a particular purpose. Each configuration may include four external side faces such as opposing front and back faces and opposing left and right side faces. In addition, each system includes at least one load port for loading and unloading substrates for coating and at least one user interface area that is usable to enter commands for controlling the gas deposition system. In the systems described below, whichever face includes the load port or ports is considered the system front face. The example gas deposition systems may comprise stand-alone gas deposition chambers as may be used in a laboratory or for low volume preproduction testing or the example gas deposition systems may be configured to cooperate with other systems such as a load lock port, substrate loading and unloading system or other automated device. The example gas deposition systems described below may be configured for zero zero footprint use wherein the entire gas deposition system is located outside a clean room or other process area where space is limited and but configured to be loaded, unloaded and operated from inside the clean room.
[0096] Referring now to
[0097] Referring to
[0098] Referring to
[0099] Referring to
[0100]
[0101] In a further step toward space saving and component sharing,
[0102]
[0103] The system (18000) may also include one or more service interface devices interconnected with the system electronic controller. In particular, each service interface device is preferably outside the clean room and may be disposed on a non-front face of a zero footprint installation, as shown. Each service interface device is usable by a service operator, shift supervisor or the like to activate system maintenance and other non-operational procedures such as for shutting down the system, including an emergency shut down, reconfiguring the system, updating system control programs, adding new coating recipes, performing diagnostic tests, and any other non-routine control functions as may be required. In particular, each service interface device may include operator input controls (18040), such as a keypad, or the like, and a display device (18010). The service interface device or devices may be located in a locked drawer outside the clean room and may be configured to take precedence over the user interface controls located inside the clean room such that the user interface devices may be non-responsive when the service interface device are being accessed or when service tasks are being performed. This increases safety for the service personnel by preventing a user from initiating operations while the system is being worked on. The system (18000) includes two complete and independent gas deposition systems supported on a single frame. Each system can be operated simultaneously and independently of the other and the single frame reduces the cost and floor space footprint when compared with two separate systems.
[0104] Referring now to
[0105] Referring now to
[0106] Referring now to
[0107] A load port (20140) comprises a rectangular conduit formed integral with or otherwise fastened to the chamber outside wall (20100). The load port (20140) includes a rectangular load port aperture (20150), shown in
[0108] In the present embodiment, the shuttle mechanism (20180) comprises a pneumatic piston that advances the link and attached cover between the up and down positions in response to air pressure changes. Other actuator mechanisms are also usable. The cover (20170) may comprise a sheet metal element formed with a semicircular arc that substantially matches the outer radius of the outer wall (20100) and sized to completely overlap the load port aperture (20150). In the down or closed position, the cover merely contacts the outer radius of the outer wall (20100) without forming a gas seal. However, as the hollow deposition chamber (20110) is pumped down to a vacuum pressure suitable for deposition coating, the cover (20170) may be drawn tightly to the outer wall to at least partially seal the load port aperture during deposition cycles. This help to contain precursor and charged plasma gases within the hollow deposition chamber (20110) in order to avoid solid material layer formation inside the load port (20140).
[0109] To further prevent deposition gasses from entering the load port (21040), a purge line and valve (20185) are connected to an inert gas supply and disposed to deliver a continuous flow of inter gas into the load port rectangular conduit between the flange (20160) and the load port aperture (20150). The inert gas flow generates a positive gas pressure gradient between the load port rectangular conduit and the hollow deposition chamber (20110). As a result, any gas leaks around the cover (20170) will tend to leak from the high-pressure side, inside the load port, to the low-pressure side, inside the hollow deposition chamber (20110) thereby further helping to contain deposition gases inside the hollow deposition chamber. In addition, the positive gas pressure gradient in the load port helps to prevent contaminates from entering the load port (20140) through the input aperture (20115). In order to avoid excessive gas pressure build up in the load port (21040), a vent tube (8170), shown in
[0110] Referring now to
[0111] The lifting mechanism includes two or more lift pins (21170) attached to a lift plate (21180) at a bottom end of the lift pins. The lift pins (21170) each movably pass through corresponding holes that pass through a top circular plate (21145) and are attached to the circular substrate support element (21150) at top ends thereof. The lift plate (21180) is circular and is housed in a gas tight chamber formed by a chamber housing (21200) that attaches to a circular middle plate (21210) with a circular o-ring or c-ring (21220) is disposed to gas seal the chamber housing (21200) with respect to the middle plate (21210). A second o-ring or c-ring (21260) is disposed to gas seal the interface between the middle plate (21210) and the hemispherical bottom portion (21110).
[0112] A transfer bracket (21220) is disposed between an actuator element (21230) and the lift plate (21180) and movably passes through a bottom wall of the chamber housing (21200). Movement of the transfer bracket (21220) may be movably guided along stationary rods (21270) that engage with the transfer bracket. A bellows (21240) is disposed between the chamber housing (21200) and the transfer bracket (21220) to gas seal the chamber housing where the transfer bracket (21220) passes through the chamber housing (21200).
[0113] In response to an electrical command, pneumatic pulse, or the like, the actuator (21230) lifts an actuator plunger (21210) upward and holds the actuator plunger (21210) in a lifted position. The upward motion of the actuator plunger (21210) is transferred to the lift pins (21170), which move through the top plate (21145) lifting the circular substrate support element (21150) out of the circular recess (21160). The substrate support element therefore lifts the substrate from the substrate support surface (21100) and supports the substrate in a load/unload position resting on the circular substrate support element (21150).
[0114] It will also be recognized by those skilled in the art that, while the invention has been described above in terms of preferred embodiments, it is not limited thereto. Various features and aspects of the above described invention may be used individually or jointly. Further, although the invention has been described in the context of its implementation in a particular environment, and for particular applications, those skilled in the art will recognize that its usefulness is not limited thereto and that the present invention can be beneficially utilized in any number of environments and implementations where it is desirable to coat objects with thin layers of solid material by gas deposition processes. Accordingly, the claims set forth below should be construed in view of the full breadth and spirit of the invention as disclosed herein.