Embodiments of the present disclosure generally relate to substrate processing equipment.
Within substrate processing equipment, for example in semiconductor substrate processing, some manufacturing processes may generate particles which frequently contaminate the substrate being processed, contributing to device defects. As device geometries shrink, susceptibility to defects increases and particle contaminant requirements become more stringent. The inventors have observed that contaminant particles can come from corrosion of the gas lines coupled to the processing equipment, for example due to corrosive gases that may be part of a particular substrate processing recipe.
Therefore, the inventors have provided improved methods and apparatus for reducing contaminants from gas lines in substrate processing equipment.
Methods and apparatus for delivering one or more gases to a process chamber are provided herein. In some embodiments a gas delivery system includes a process chamber having an inner volume; a gas source panel; a gas line coupling the inner volume to the gas source panel; and a first gas filter disposed along the gas line proximate the inner volume, wherein the first gas filter comprises a filter element body having a first end and a second end opposite the first end, and a filtration efficiency of about 1 to about 5 log reduction value (LRV).
In some embodiments, a substrate processing apparatus includes: a process chamber comprising a chamber body having sidewalls, a bottom, and a chamber lid that together define an inner volume of the process chamber; one or more gas inlet ports disposed through the chamber body and fluidly coupled to the inner volume; a substrate support disposed within the inner volume; and one or more first gas filters having a filtration efficiency of about 1 to about 5 LRV coupled to the inner volume at a location proximate to the process chamber.
In some embodiments, a method for delivering a gas into a process chamber includes: flowing a gas through a gas line from a gas panel having a gas panel filter to an inner volume of a process chamber; and flowing the gas through a first gas filter disposed downstream of the gas panel filter and proximate the inner volume of the process chamber, wherein the first gas filter has a filtration efficiency of about 1 to about 5 LRV.
Other and further embodiments of the present disclosure are described below.
Embodiments of the present disclosure, briefly summarized above and discussed in greater detail below, can be understood by reference to the illustrative embodiments of the disclosure depicted in the appended drawings. However, the appended drawings illustrate only typical embodiments of the disclosure and are therefore not to be considered limiting of 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. The figures are not drawn to scale and may be simplified for clarity. Elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.
Methods and apparatus for improved substrate processing equipment are provided herein. Embodiments of the present disclosure provide improved filtering of process gas contaminant particles that can be found in the supply gas lines of substrate processing equipment. For example, for semiconductor applications, such as etching processes, corrosive agents (such as comprising chlorine gas) are often used. The gas line systems are typically made out of low cost 312L stainless steel material. Stainless steel material usually has good corrosion resistance against chlorine gases, however, during chamber maintenance the gas lines are exposed to atmosphere. The moisture from the ambient and the residual chlorine gas adsorbed to the gas line surface react with each other and form hypochlorous acid (HClO), an oxidizing corrosive media which condenses on the internal surfaces of the gas line. HClO is severely corrosive and results in pitting corrosion of the gas line especially in the regions close to grain boundaries and localize carbides. The aforementioned corrosion issue results in the formation of corrosion by-products in the form of small particles. During process chamber operation, these particles will be carried to the chamber and cause substrate particle defects and metal contamination. The inventors have observed that particles with signatures of oxides of iron, for example, iron oxide, iron chromium oxide, and iron nickel oxide may be found on substrates, especially immediately following maintenance of stainless steel gas lines. The inventors have also observed that the same type of corrosion can also occur on other gas delivery system components such as valves, pressure gages, gas valve diaphragm, and the like, whether made of stainless steel or materials other than stainless steel. The inventors have discovered that the gas filter of the present disclosure may advantageously reduce the amount of contaminant particles that reach substrates. The gas filters can inserted to the locations similar to but not limited to gas line endpoint, gas hub, showerhead gas inlet, or the like.
In addition to contaminants from corrosion of the gas line, other sources of contamination may be advantageously addressed by the present disclosure. The inventors have discovered that substrates may also be contaminated by particles accumulated inside the gas lines due to erosion of o-rings and/or backstream condensation of process gases during or after previously performed substrate processing. For example, the inventors have observed that aluminum oxide based nanoparticles may form inside a gas line of an etch tool due to condensation of back streamed process chemistry gases.
The gas delivery system 100 may be coupled to a process chamber 102, for example, having an inner volume 104 surrounded by chamber body 106. In the exemplary embodiment depicted in
In some embodiments, the showerhead 122 may be configured to function as an RF electrode. As shown in
An exhaust system 126 comprising an exhaust port 128 for passing exhaust gases out of the inner volume 104 is coupled to the process chamber 102.
The gas delivery system 100 includes a gas line 130 provided to flow and deliver gases into the inner volume 104 of the process chamber 102. One or more first gas filters (e.g., first gas filters 132, 134, and 136 shown) are coupled to the gas line 130 proximate respective endpoints of the gas line 130, for example, adjacent the inner volume 104. In some embodiments, the first gas filter may be disposed in a gas line downstream of all gas sources and flow control devices (such as mass flow controllers, flow ratio controllers, valves, fixed orifices, or the like) in the gas line such that no flow control component (other than the terminal portion of the gas line) is disposed between the first gas filter and the chamber component to which the gas line is coupled, such as a showerhead, gas distribution hub, gas nozzle, or the like. In some embodiments, the first gas filter may be incorporated into the chamber component that delivers the gas to the inner volume 104 (e.g., the showerhead, gad distribution hub, gas nozzle, or the like). In some embodiments, the first gas filter may be disposed in a gas line downstream of all gas sources and flow control devices other than a shutoff valve disposed just upstream of the terminal portion of the gas line.
In some embodiments, the first gas filters (e.g., first gas filters 132,134, 136) may be fluidly coupled to the inner volume 104 via one or more components of the process chamber 102. For example, as depicted in the exemplary embodiment of
In some embodiments, the first gas filters (e.g., first gas filters 132, 134, 136) may be disposed through the chamber body 106 (or provided in other locations). For example, as illustrated in
The gas delivery system 100 further includes a gas panel 138 coupled to the inner volume 104 by the gas line 130. The gas panel 138 comprises one or more gas sources (gas source 140 shown) containing one or more gases for use in processes within the inner volume 104. In some embodiments, the gas panel 138 may include a second gas filter 142. The second gas filter 142 may have a filtration efficiency of at least about 9 log reduction value (LRV) (out of 1×109 particles >20 nm, one will pass through the filter). The second gas filter 142, located in a relatively high pressure area of the gas delivery system 100 (e.g., near the gas source 140), can use a high efficiency filter such as a 9 LRV gas filter suitable for removing particles in the gas provided by the gas source 140.
In some embodiments, the gas delivery system 100 includes a flow splitter 144 to apportion gases from the gas panel 138 to various endpoints of the gas line 130 disposed in respective process chamber locations. For example, as depicted in
The filter element body 202 comprises one or more materials having corrosion resistance to commonly used process gases, for example Cl2, O2, SiCl4, NF3, NH4, CH2, and others. In some embodiments, the filter element body 202 may be made from stainless steel (such as 316L SST), nickel, or nickel-based alloys (such as an alloy comprising nickel, chromium, iron, molybdenum, cobalt, and tungsten, for example HASTELLOY®, commercially available from Haynes International, located Kokomo, Ind.), or the like. The filter is made with partially sintered powder of the above materials having a porosity permeable for process gases but not for large enough particles. The sintered filter material has a larger porosity matrix, as compared to conventional gas filters, advantageously providing significantly less pressure drop and delay. Hence, the gas filter can be used in low pressure regions unlike traditional gas filters. The gas filter can also be made in small cylindrical or disk shapes which can advantageously be easily installed at the ends of gas lines or gas hubs with no major design changes.
In some embodiments, for example, in the non-limiting exemplary embodiment depicted in
In some embodiments, the inner diameter of the midsection 208 may be about 0.125 inches to about 2.00 inches, or in some embodiments, about 0.125 inches to about 0.25 inches. In some embodiments, the outer diameter of the midsection 208 may be about 0.125 inches to about 1 inch. In some embodiments, the length of the midsection 208 may be in a range from about 0.50 inches to about 10 inches. In some embodiments, the surface area of the inner surface 212 may be, for example, between about 0.2 square inches and about 63 square inches. Other dimensions having other surface areas may also be used in certain applications depending upon the gas flow characteristics required.
Returning to
The length of the first gas filter may vary depending on the total flow passing through the gas line 130. In some embodiments, the length of the first gas filter may be about 0.5 inches to about 8 inches. In addition, the length, diameter, or other configuration of each first gas filter may vary depending upon the location of use. For example, in some processing systems first gas filters provided in some gas delivery locations or zones may be longer than other first gas filters provided in other gas delivery locations or zones. For example, zones that receive more of the total gas flow may use longer first gas filters than zones that receive less of the total gas flow.
In some embodiments, the filter element body 202 may be in the form of a disc rather than a tube. A disc shaped filter may be advantageous, for example, with gas line endpoints having substantially larger cross sectional areas.
In some embodiments, the gas hub 300 may be disposed atop the chamber lid 108 (depicted in
The hub body 302 is connected to the endpoint of the gas line 130 proximate the process chamber 102. A collar 304 having one or more seals 306 (for example, a gasket, o-ring, or the like) attaches the hub body 302 to the endpoint of the gas line 130 while preventing or limiting any gas leaks at the interface of the gas line 130 and the gas hub 300. An opening 320 in the collar 304 fluidly couples the first gas filter 132 to the gas line 130.
The hub body 302 includes a passageway 308 having a diameter greater than the diameter of the first gas filter 132 to define a gap 310 between the outer surface 214 of the first gas filter 132 and the surface of the hub body 302 along the passageway 308. The gap 310 is provided to facilitate passing filtered gas from the first gas filter 132 into the inner volume 104 depicted in
In some embodiments, the passageway 308 may include a counterbore formed at the outer surface of the hub body 302 defining a shoulder 322 near the end of the passageway 308. The first gas filter 132 may include a flange 324 proximate the end of the first gas filter 132 to rest on the shoulder 322 when installed and to facilitate proper placement of the first gas filter 132 in the hub body 302. A seal 316 (similar to seals 306, 312) may be provided around the end of the first gas filter 132 and adjacent to the flange 324. The seal 316 sits in a space defined by the outer diameter of the end of the first gas filter 132, the flange 324, an inner surface of the counterbore, and the adjacent surface of the collar 304 and prevents or limits any gas from bypassing the first gas filter 132 when flowing into the passageway 308. A portion 326 of the first gas filter 132 adjacent to the flange 324 may be provided with an enlarged diameter slightly smaller than the diameter of the passageway 308 to facilitate positioning and holding the first gas filter 132 in place within the passage. The enlarged diameter portion 326 of the first gas filter 132 may also further minimize risk of gas bypassing the first gas filter 132.
A conduit 314 having a passage volume 318 couples the passageway 308 (and gap 310) to the inner volume 104, for example through the showerhead 122, as illustrated by the directional arrow pointing in the direction of the inner volume 104. Although not shown, the chamber lid 108 of the process chamber may have additional conduits as needed to control the flow of gas to desired locations within the process chamber.
The stem 404 (and inner surface of the gas line 130) and an outer surface 412 of the first gas filter 132 define a gap 410 surrounding the outer surface 412. The gap 410 is provided to facilitate flow of gas through the first gas filter 132. Although
The flange section 402 of the elongated flange 401 is coupled to a gas distribution component 408 of the process chamber, for example by bolting or clamping. The gas distribution component 408 may be part of a gas hub, showerhead, or other component coupled to the end of gas line 130 proximate the process chamber. The flange section 402 includes a seal 406 (similar to seals 306, 312, 316 discussed above) to prevent or limit gas leaks at the interface between the flange section 402 and the gas distribution component 408.
In some embodiments, the flange section 402 may include a counterbore formed at the end of the flange section 402 defining a shoulder 416 near the end of the flange section 402. The first gas filter 132 may include a flange 418 proximate the end of the first gas filter 132 to rest on the shoulder 416 when installed and to facilitate proper placement of the first gas filter 132 in the flange section 402. A seal 414 (similar to seals 306, 312, 316, and 406) may be provided around the end of the first gas filter 132 within a groove formed in the outer diameter of the flange 418. The seal 414 sits in a space defined by the groove in the flange 418 and an inner surface of the counterbore and prevents or limits any gas from bypassing the first gas filter 132. A portion 420 of the first gas filter 132 adjacent to the flange 418 may be provided with an enlarged diameter slightly smaller than the inner diameter of the elongated flange 401 to facilitate positioning and holding the first gas filter 132 in place within the passage. The enlarged diameter portion 420 of the first gas filter 132 may also further minimize risk of gas bypassing the first gas filter 132.
In operation, as illustrated in
However, the inventors have observed that as the one or more gases flow along the gas line 130, corrosion of the gas line 130 and the other flow components, for example, the flow splitter 144 or the gas flow control elements 146, 148, 150 may undesirably contaminate the one or more gases before they are delivered to the inner volume 104. The first gas filters 132, 134, 136 provided with a filtration efficiency of about 1 LRV to about 5 LRV, for example, about 2 LRV to about 4 LRV, are advantageously coupled to the gas line 130, proximate endpoints of the gas line 130 disposed proximate the inner volume 104. Thus, the first gas filters 132, 134, 136 perform a filtration of the one or more gases immediately prior to delivery of the gas into the inner volume 104.
In some embodiments, the first gas filters 132, 134, 136 may provide the same filtration efficiency to gases flowing in the gas line 130 and incident upon the inner surfaces 212 of the first gas filters 132, 134, 136 at a flow rate between about 10 sccm to about 10,000 sccm. In some embodiments according to the present disclosure, the first gas filters 132, 134, 136 may provide a similar filtration efficiency even when located in region of low pressure, for example, relative to the pressure inside the gas line 130 at an exit point of the gas panel 138. For example, the first gas filters 132, 134, 136 may be located in a portion of the gas line 130 proximate the inner volume having a pressure less than 500 mTorr, for example, between about 1 mTorr and 500 mTorr.
When provided as part of the gas delivery system 100, the first gas filter (e.g., 132, 134, or 136) further ensures a stable pressure difference in inside the gas line 130, between a first point located upstream of the first gas filter (e.g., 132, 134, or 136) and a second point located downstream of the first gas filter (e.g., 132, 134, or 136). For example, when using the exemplary first gas filter 132 having a filtration efficiency of about 1 LRV to about 5 LRV pressure build up in the gas line 130 which may otherwise occur due to filter induced gas flow blockage on the inner surface 212, is advantageously avoided, and a stable pressure difference between the inner surface 212 and the outer surface 214 is maintained. Accordingly, the first gas filter (e.g., 132, 134, or 136) allows for uninterrupted flow of the one or more gases, for example by delaying the flow by a negligible amount of time, for example, by less than 0.2 seconds.
A controller 152 may be provided and coupled to various components of the gas delivery system 100 to control the operation of the gas delivery system 100. The controller 152 includes a central processing unit (CPU) 154, support circuits 156 and a memory or computer readable medium 158, and support circuits 156. The controller 152 may control the gas delivery system 100 directly, or via computers (or controllers) associated with particular process chamber and/or support system components. The controller 152 may be any form of general-purpose computer processor that can be used in an industrial setting for controlling various chambers and sub-processors. The memory, or computer readable medium, 158 of the controller 152 may be one or more of readily available memory such as random access memory (RAM), read only memory (ROM), floppy disk, hard disk, optical storage media (e.g., compact disc or digital video disc), flash drive, or any other form of digital storage, local or remote. The support circuits 156 are coupled to the CPU 154 for supporting the processor in a conventional manner. These circuits include cache, power supplies, clock circuits, input/output circuitry and subsystems, and the like. Inventive methods as described herein, such as the method for providing one or more gases to a process chamber, may be stored in the memory 158 as software routine 160 that may be executed or invoked to control the operation of the gas delivery system 100 in the manner described herein. The software routine may also be stored and/or executed by a second CPU (not shown) that is remotely located from the hardware being controlled by the CPU 154.
Thus, improved gas filters and gas delivery systems incorporating such gas filters have been provided herein. The methods and systems disclosed herein provide process gas contaminant particle filtering that may advantageously be utilized in low pressure regions of a processing equipment supply gas line.
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.
This application claims benefit of U.S. provisional patent application Ser. No. 62/414,173, filed Oct. 28, 2016, which is herein incorporated by reference in its entirety.
Number | Date | Country | |
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62414173 | Oct 2016 | US |