1. Field
Embodiments of the present disclosure generally relate to reduced-pressure processing techniques. More particularly, embodiments of the present disclosure relate to a one-piece injector assembly for directing the flow of process gases into a reduced-pressure processing system.
2. Description of the Related Art
Semiconductor substrates are processed for a wide variety of applications, including the fabrication of integrated devices and microdevices. One technique for processing substrates includes exposing the substrate to gases at reduced pressures and causing the gases to deposit a material, such as dielectric material or a conductive metal, on a surface of the substrate. For example, epitaxy is a deposition process that may be used to grow a thin, high-purity layer, usually of silicon or germanium, on a surface of a substrate (e.g., a silicon wafer). The material may be deposited in a cross-flow chamber by flowing a process gas (e.g., a mixture of precursor gases and carrier gases) parallel to, and across, the surface of a substrate positioned on a support, and decomposing (e.g., by heating the process gas to high temperatures) the process gas to deposit a material from the process gas onto the surface of the substrate.
The quality of the deposited film in epitaxy is directly affected by the precision with which gas flows and temperature are controlled in a process chamber. Flow control and temperature control are affected by the design of the process chamber, including the design of one or more liner rings, injectors, injector assemblies, and exhaust ports. Flow of the process gases may be controlled to allow the flow rate of process gas across the substrate to differ on different pathways (e.g., flow rate may be faster within a central pathway than within pathways near edges of a substrate), in order to improve thickness uniformity of the deposited layer across the entire substrate.
To control the relative flow rates of process gas having different flow rates on different paths across the substrate to affect the thickness uniformity of the deposited film, there is a need for a one-piece injector assembly with isolation between separate process gas pathways therethrough.
An injector assembly is provided. The injector assembly generally comprises a one piece construct configured with multiple independently controllable channels therethrough by which one or more fluids may be flowed therethough and into a reduced-pressure processing chamber.
A lower liner for a reduced-pressure processing chamber is provided. The lower liner generally includes a ring-shaped body configured with a portion removed therefrom to accommodate an injector assembly and a portion cut-away therefrom to allow rotation of the lower liner during installation of the lower liner and the injector assembly in the reduced-pressure processing chamber.
An upper liner for a reduced-pressure processing chamber is provided. The upper liner generally includes a ring-shaped body configured with a portion thereof cut-away to accommodate an injector assembly and a thicker portion configured to line a region of the processing chamber adjacent to the cut-away portion of a lower liner.
A method for installing a one-piece injector assembly in a reduced-pressure processing chamber is provided. The method generally includes rotating a lower liner of the reduced-pressure processing chamber to align a first portion cut-away from the lower liner with an injection cap of the reduced-pressure processing chamber, inserting the one-piece injector assembly through the first portion cut-away from the lower liner and into contact with the injection cap of the reduced-pressure processing chamber, rotating the lower liner to align the first portion cut-away from the lower liner with a loading port of the reduced-pressure processing chamber, and inserting an upper liner into the reduced-pressure processing chamber while simultaneously aligning a first portion cut-away from the upper liner with the one-piece injector assembly, a thicker portion of the upper liner with the first portion cut-away from the lower liner, and a second portion cut-away from the upper liner with a second portion cut-away from the lower liner.
An exhaust liner is provided. The exhaust liner generally comprises a one-piece construct configured with a channel therethrough by which one or more fluids may flow therethough and exit a reduced-pressure processing chamber.
So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this disclosure and are therefore not to be considered limiting of its scope, for the disclosure may admit to other equally effective embodiments.
To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one embodiment may be beneficially utilized in other embodiments without specific recitation.
Methods and apparatuses for controlling and directing flow of process gases into a processing chamber are provided. The methods and apparatuses enable introduction of process gases into a processing chamber in a manner allowing the process gases to flow across a substrate within the processing chamber in a plurality of parallel pathways.
One embodiment disclosed herein is a gas inlet mechanism consisting of a one-piece injector assembly with multiple independent flow channels extending therethrough in isolation from one another.
In another embodiment, a lower liner of a processing chamber includes a portion thereof cut-out to accommodate an injector assembly and a second portion thereof cut-out to allow rotation of the lower liner past the injector assembly during installation of the lower liner and the injector assembly in the reduced-pressure process chamber.
In another embodiment, an upper liner of a processing chamber includes a portion thereof cut-out to accommodate an injector assembly and a thicker portion configured to line an area of the process chamber adjacent to a cut-out portion of a lower liner.
In another embodiment, a method is provided to install an injector mechanism in a processing chamber by rotating a lower liner of the processing chamber such that a first portion cut-away from the lower liner is aligned with an injection cap of the processing chamber, inserting the injector mechanism through the first portion cut-away from the lower liner and into contact with the injection cap of the processing chamber, rotating the lower liner to align the first portion cut-away from the lower liner with a loading port of the processing chamber, and inserting an upper liner into the processing chamber while simultaneously aligning a first portion cut-away from the upper liner with the one-piece injector assembly, a thicker portion of the upper liner with the first portion cut-away from the lower liner, and a second portion cut-away from the upper liner with a second portion cut-away from the lower liner.
In another embodiment, a method is provided to flow process gases into a processing chamber through separate channels of a one-piece injector assembly.
Referring to
The substrate 108 (not to scale) can be brought into the processing chamber 100 through a loading port 103 and positioned on the substrate support 106. The loading port 103 is obscured by the substrate support 106 in
According to one embodiment, the substrate support 106 is supported by a central shaft 132, which may directly support the substrate support 106 as shown in
According to one embodiment, the processing chamber 100 also comprises a lamphead 145, which supports the array of lamps 102 and cools the lamps 102 during and/or after processing. Each lamp 102 is coupled to an electrical distribution board (not shown), which supplies electricity to each lamp 102.
A circular shield 167, which may be a preheat ring, may be optionally disposed around the substrate support 106 and surrounded by a liner assembly 163. The circular shield 167 prevents or reduces leakage of heat and or light noise from the lamps 102 to the device side 116 of the substrate 108 while providing a pre-heat zone for the process gases. The circular shield 167 is made from chemical vapor deposited (CVD) SiC, sintered graphite coated with SiC, grown SiC, opaque quartz, coated quartz, or any similar, suitable material that is resistant to chemical breakdown by process and purging gases.
The liner assembly 163 is sized to be nested within or surrounded by an inner circumference of the base ring 136. The liner assembly 163 shields the metallic walls of the processing chamber 100 from the process gases used in processing. The metallic walls may react with the process gases and be damaged or introduce contamination into the processing chamber 100. While the liner assembly 163 is shown as a single body, in embodiments of the present disclosure, the liner assembly 163 comprises one or more liners and other components, as described below and shown in
According to one embodiment, the processing chamber 100 also includes one or more optical pyrometers 118, which measure temperatures within the processing chamber 100 and on the surface of substrate 108. A controller (not shown) controls electricity distribution from the electrical distribution board to the lamps 102. The controller also controls flows of cooling fluids within the processing chamber 100. The controller controls temperatures within the process chamber by varying the electrical voltage from the electrical distribution board to the lamps 102 and by varying the flows of cooling fluids.
A reflector 122 is placed outside the upper dome 128 to reflect infrared light radiating from the substrate 108 and upper dome 128 back into the processing chamber 100. The reflector 122 is secured to the upper dome 128 using a clamp ring 130. The reflector 122 has one or more connection ports 126 connected to a cooling fluid source (not shown). The connection ports 126 connect to one or more passages (not shown) within the reflector to allow cooling fluid (e.g., water) to circulate within the reflector 122.
According to one embodiment, the processing chamber 100 comprises a process gas inlet 174 connected to a process gas source 172. The process gas inlet 174 is configured to direct process gas generally across the surface of the substrate 108. The process chamber also comprises a process gas outlet 178 located on the side of the processing chamber 100 opposite the process gas inlet 174. The process gas outlet 178 is coupled to a vacuum pump 180.
According to one embodiment, the processing chamber 100 comprises a purge gas inlet 164 formed in the sidewall of the base ring 136. A purge gas source 162 supplies purge gas to the purge gas inlet 164. If the processing chamber 100 comprises a circular shield 167, the circular shield 167 is disposed between the process gas inlet 174 and the purge gas inlet 164. The process gas inlet 174, purge gas inlet 164, and process gas outlet 178 are shown for illustrative purposes, and the position, size, number of gas inlets and outlets, etc. may be adjusted to facilitate a uniform deposition of material on the substrate 108.
The substrate support is shown in a position to allow processing of a substrate in the process chamber. The central shaft 132, substrate support 106 or 107, and arms 134 may be lowered by an actuator (not shown). A plurality of lift pins 105 passes through the substrate support 106 or 107. Lowering the substrate support to a loading position below the processing position allows lift pins 105 to contact the lower dome 114, pass through holes in the substrate support 106 and the central shaft 132, and raise the substrate 108 from the substrate support 106. A robot (not shown) then enters the processing chamber 100 to engage and remove the substrate 108 though the loading port 103. The robot or another robot enters the process chamber through the loading port 103 and places an unprocessed substrate on the substrate support 106. The substrate support 106 then is raised to the processing position by the actuator to place the unprocessed substrate in position for processing.
According to one embodiment, processing of a substrate 108 in the processing chamber 100 comprises inserting the substrate through the loading port 103, placing the substrate 108 on the substrate support 106 or 107, raising the substrate support 106 or 107 and substrate 108 to the processing position, heating the substrate 108 by the lamps 102, flowing process gas 173 across the substrate 108, and rotating the substrate 108. In some cases, the substrate may also be raised or lowered during processing.
According to some aspects of the present disclosure, epitaxial processing in processing chamber 100 comprises controlling the pressure within the processing chamber 100 to be lower than atmospheric pressure. According to one embodiment, pressure within the processing chamber 100 is reduced to be between approximately 10 torr and 80 torr. According to another embodiment, pressure within the processing chamber 100 is reduced to be between approximately 80 torr and 300 torr. According to one embodiment, the vacuum pump 180 is activated to reduce the pressure of the processing chamber 100 before and/or during processing.
The process gas 173 is introduced into the processing chamber 100 from one or more process gas inlets 174, and exits the processing chamber 100 through one or more process gas outlets 178. The process gas 173 deposits one or more materials on the substrate 108 through thermal decomposition, for example, or other reactions. After depositing materials on the substrate 108, effluent (i.e., waste gases) 166, 175 are formed from the reactions. The effluent 166, 175 exits the processing chamber 100 through the process gas outlets 178.
When processing of a substrate 108 is complete, the process chamber is purged of process gas 173 and effluent 166, 175 by introducing purge gas 165 (e.g., hydrogen or nitrogen) through the purge gas inlets 164. Purge gas 165 may be introduced through the process gas inlets 174 instead of, or in addition to, the purge gas inlets 164. The purge gas 165 exits the process chamber through the process gas outlets 178.
Exemplary One-Piece Injector Assembly and Liner Assembly
In embodiments of the present disclosure, the process gas flows across the substrate in a plurality of parallel pathways. In one embodiment, one of the pathways intersects the central axis of the processing chamber 100. The process gas flows across the substrate at different rates in the different pathways, for example, the process gas flows fastest in a central pathway, with decreasing flow rates in pathways further from the central axis. Varying the flow rates of the process gas in the pathways improves thickness uniformity of a deposited layer as compared to a layer deposited by process gas flowing across the entire surface of the substrate at a single flow rate.
In some embodiments, the process gas that is supplied to the process chamber comprises multiple types of process gases, for example, a group III precursor gas (e.g., trimethylindium (In(CH3)3) and a group V precursor gas (e.g., phosphine (PH3)). In some embodiments, the multiple process gases are supplied to the process chamber through separate process gas inlets. In some embodiments, the multiple process gases are supplied at a plurality of pressures.
In some embodiments, process gas is supplied to the injector inlets 204 in separate streams at a plurality of pressures and/or flow rates by the process gas source 172. The separate channels 202 of the one-piece injector assembly 200 enable the separate streams of process gas to enter the processing chamber 100 through the process gas inlets 206 at a plurality of pressures and/or flow rates. The flow rate of process gas across the surface of the substrate 108 may be affected by the pressure of the process gas when entering the processing chamber 100. By maintaining the separate streams of process gas, the separate channels of the one-piece injector assembly 200 enable the process gas to flow across the substrate at differing flow rates in different regions. For example, process gas supplied to the process chamber through a central process gas inlet may be supplied at a higher flow rate and/or pressure than process gas supplied to a process gas inlet other than the central process gas inlet. The arc-shaped surface 208 may enable each of the process gas inlets 206 to be at a same distance from a substrate 108 being processed in a processing chamber 100.
In some embodiments, the process gas comprises a mixture of multiple process gases. The separate channels 202 of the one-piece injector assembly 200 enable the multiple types of process gases to enter the processing chamber 100 through the process gas inlets 206 without mixing before entering the processing chamber 100, by, for example, introducing different gases in alternating channels across the plane of the substrate.
According to certain embodiments, the one-piece injector assembly 200 is combined with a liner assembly (e.g., an upper liner and a lower liner) configured to ease installation of the one-piece injector assembly 200 in processing chamber 100.
The upper liner 300 is assembled together with the one-piece injector assembly 200 by aligning the one-piece injector assembly with the cut-away portion 302 of the upper liner 300 as the upper liner 300 is installed into the processing chamber 100. A thicker portion 304 of the upper liner 300 aligns with a cut-away portion 404 of the lower liner 400 to protect the processing chamber 100 wall from exposure to process gases while allowing use of loading port 103 for access to the interior of processing chamber 100. The upper liner 300, one-piece injector assembly 200, one-piece exhaust liner 500, and lower liner 400 are installed between the upper dome 128 and the lower dome 114 in the processing chamber 100. As described above, the cut-away portion 404 of the lower liner 400 is at an angle of approximately 90° from the channels 202 of one-piece injector assembly 200 when the one-piece injector assembly 200 and lower liner 400 are installed in the processing chamber 100. As shown in
While
According to one embodiment, processing of a substrate 108 in the processing chamber 100 using the one-piece injector assembly 200 is similar to processing in the processing chamber 100 described above. Processing of a substrate 108 in the processing chamber 100 using the one-piece injector assembly 200 may comprise inserting the substrate through the loading port 103, placing the substrate 108 on the substrate support 106 or 107, raising the substrate support 106 or 107 and substrate 108 to the processing position, heating the substrate 108 by the lamps 102, flowing process gas 173 across the substrate 108, and rotating the substrate 108. In some cases, the substrate may also be raised or lowered during processing.
In the case of performing epitaxial deposition using a single type of process gas in processing chamber 100 using the one-piece injector assembly 200, the single type of process gas is supplied to each of the injector inlets 204 by an injection cap. Referring again to
Upon exiting the process gas inlets 206 of the one-piece injector assembly, the process gas flows across and parallel to the upper surface of the substrate. As described above, the process gas inlet passages are generally parallel to the upper surface of the substrate, causing the process gas to flow parallel to the upper surface of the substrate in a laminar flow pattern. Supplying the process gas at a higher flow rate across the center of the substrate improves the thickness uniformity of a deposited layer from epitaxial deposition, as compared to a deposited layer from flowing process gas across the entire substrate at a single flow rate.
In the case of performing epitaxial deposition using multiple types of process gas in processing chamber 100 using the one-piece injector assembly 200, a mixture of the multiple types of process gas is supplied to each of the injector inlets 204 by an injection cap. Referring again to
Upon exiting the process gas inlets 206 of the one-piece injector assembly, the process gas flows across and parallel to the upper surface of the substrate. As described above, the process gas inlet passages are generally parallel to the upper surface of the substrate, which causes the process gas to flow parallel to the upper surface of the substrate in a laminar flow pattern. Preventing the flows of process gas from mixing before entering the process chamber improves the thickness uniformity of a deposited layer from epitaxial deposition.
A system controller (not shown) can be used to regulate the operations of the processing chamber 100. The system controller can operate under the control of a computer program stored on a hard disk drive of a computer. For example, the computer program can dictate the process sequencing and timing, mixture of gases, chamber pressures, RF power levels, susceptor positioning, slit valve opening and closing, and other parameters of a particular process.
To provide a better understanding of the foregoing discussion, the above non-limiting examples are offered. Although the examples may be directed to specific embodiments, the examples should not be interpreted as limiting the disclosure in any specific respect.
While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.
This application claims benefit of U.S. provisional patent application Ser. No. 62/013,978, filed Jun. 18, 2014, and U.S. provisional patent application Ser. No. 62/015,225, filed Jun. 20, 2014, which are herein incorporated by reference.
Number | Date | Country | |
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62015225 | Jun 2014 | US | |
62013978 | Jun 2014 | US |