KR20210148406A - Ground Strap Assemblies - Google Patents

Abstract

The present disclosure relates to methods and apparatus for plasma processing a substrate. In one embodiment, the substrate processing chamber includes a ground strap assembly. The grounding strap assembly includes a grounding strap and one or more connectors coupled to the substrate support and/or the chamber body. Each connector has a first clamp member and a second clamp member. A ground strap is fastened between the first clamp member and the second clamp member of each connector. An inner surface of each of the first and second clamp members is coupled to a ground strap and coated with a dielectric coating. Modification of the thickness and roughness of the inner surfaces enables adjustment of the capacitance characteristics of the connectors.

Description

Ground Strap Assemblies

[0001] Embodiments of the present disclosure generally relate to methods and apparatus for processing substrates, such as semiconductor substrates, using plasma. More particularly, embodiments of the present disclosure relate to radio frequency (RF) ground strap assemblies for plasma processing chambers.

[0002] Plasma enhanced chemical vapor deposition (PECVD) is used to process substrates, such as semiconductor substrates, solar panel substrates and flat panel display substrates. PECVD is generally performed by introducing one or more precursor gases into a vacuum chamber having a substrate, where the substrate is placed on a substrate support in the vacuum chamber. The precursor gases are directed towards the process volume through a gas distribution plate, typically placed near the top of the vacuum chamber. The precursor gases are energized (eg, excited) into the plasma by applying electrical power, such as radio frequency (RF) power, to the electrode by one or more power sources coupled to the electrode in the chamber. The excited gas or gas mixture then reacts to form a material film layer on the surface of the substrate disposed on the substrate support. The material film layer may be, for example, a passivation layer, a gate insulator, a buffer layer and/or an etch stop layer.

[0003] During processing, the substrate support is electrically grounded to cancel any voltage drop across the substrate support, which will affect the deposition uniformity of the material film layer across the surface of the substrate. Additionally, if the substrate support is not properly grounded, the high electrical potential difference between the substrate support and the chamber body can result in electrical arcing and forming parasitic plasmas between the substrate support and the chamber body. This results in particle formation, metal contamination, non-uniform deposition, yield loss and hardware damage. The parasitic plasma reduces the concentration and density of the capacitively coupled plasma in the chamber, thus reducing the deposition rate of the material film layers.

[0004] To minimize arcing and the generation of parasitic plasma in a large area plasma chamber, the substrate support is typically grounded to the chamber body by thin flexible ground straps to form a current return path. However, conventional ground strap arrangements provide electrical return paths with significant electrical inductance (eg, impedance) at radio frequencies such as 13.56 MHz and above. Thus, a significant voltage potential difference still remains between the substrate support and the chamber body, leading to unwanted arcing and parasitic plasma formation at the periphery of the substrate support.

[0005] Accordingly, there is a need in the art for an improved substrate processing apparatus having ground strap assemblies having reduced electrical impedance.

[0006] The present disclosure relates to methods and apparatus for plasma processing a substrate. In one embodiment, a substrate processing chamber is provided. A substrate processing chamber includes a chamber body having one or more chamber walls that partially define a process volume and a chamber bottom coupled to the one or more chamber walls. The chamber bottom further includes a chamber connector coupled to the chamber bottom, the chamber connector having a first clamping member coupled to the second clamping member by one or more fasteners. The substrate support is disposed in the process volume and includes a support connector coupled to the substrate support. The support connector has a first clamping member coupled to the second clamping member by one or more fasteners. The ground strap is coupled to the substrate support by a support connector at a first end and coupled to the bottom of the chamber by a chamber connector at a second end. A dielectric coating is formed on one or more surfaces of the support connector and/or chamber connector configured to contact the ground strap.

[0007] In one embodiment, a grounding strap assembly is provided. The grounding strap assembly includes a chamber connector and a support connector, wherein a dielectric coating is formed on one or more surfaces of each of the chamber connector and support connector. The grounding strap assembly further includes a grounding strap having a first end coupled to the support connector and a second end coupled to the chamber connector. The support connector and chamber connector function as capacitors.

[0008] In one embodiment, a grounding strap assembly is provided. The grounding strap assembly includes a grounding strap having a first end coupled to the support connector and a second end coupled to the chamber connector. The first and second ends of the ground strap are formed of a dielectric material, and the chamber and support connectors function as capacitors at the first and second ends.

[0009] In such a way that the above-mentioned features of the present disclosure may be understood in detail, a more detailed description of the disclosure briefly summarized above may be made with reference to embodiments, some of which are attached illustrated in the drawings. It should be noted, however, that the appended drawings illustrate only exemplary embodiments and are not to be considered limiting of their scope, as they may admit to other equally effective embodiments.
1 illustrates a cross-sectional view of a substrate processing system having therein one or more ground straps coupled to a substrate support, in accordance with one embodiment of the present disclosure;
2 illustrates a side view of an exemplary grounding strap according to an embodiment of the present disclosure;
3 illustrates a cross-sectional view of a portion of the substrate processing chamber of FIG. 1 ;
4A illustrates a cross-sectional view of a portion of a grounding strap assembly according to an embodiment of the present disclosure;
4B illustrates a cross-sectional view of a portion of a grounding strap assembly according to an embodiment of the present disclosure;
5 illustrates a cross-sectional view of a grounding strap assembly according to an embodiment of the present disclosure;
To facilitate understanding, like reference numbers have been used where possible to designate like elements that are common to the drawings. It is contemplated that elements and features of one embodiment may be beneficially incorporated into other embodiments without further recitation.

[0017] The present disclosure relates to methods and apparatus for plasma processing a substrate. In one embodiment, the substrate processing chamber includes a ground strap assembly. The grounding strap assembly includes a grounding strap and one or more connectors coupled to the substrate support and/or the chamber body. Each connector has a first clamp member and a second clamp member. A ground strap is fastened between the first clamp member and the second clamp member of each connector. An inner surface of each of the first and second clamp members is coupled to a ground strap and coated with a dielectric coating. Modification of the thickness, roughness and dielectric constant of the inner surfaces enables the adjustment of the capacitance characteristics of the connectors.

[0018] Embodiments herein are illustratively described below with reference to use in a PECVD system configured to process substrates, such as a PECVD system available from Applied Materials, Inc. of Santa Clara, CA. However, it should be understood that the disclosed subject matter is useful in other system configurations, such as etching systems, other chemical vapor deposition systems, and any other system in which a substrate is exposed to plasma within a process chamber. It should further be understood that the embodiments disclosed herein may be practiced using chambers using different types of substrates and process chambers provided by other manufacturers. It should also be understood that the embodiments disclosed herein may be adapted for practice in other process chambers configured to process substrates of various shapes, sizes and dimensions.

[0019] 1 is a cross-sectional view of a substrate processing system 100, such as a PECVD apparatus, according to one embodiment. Substrate processing system 100 uses plasma to use plasma during fabrication of liquid crystal displays (LCDs), flat panel displays, organic light emitting diodes (OLEDs) or photovoltaic cells for solar cell arrays. ) to process. The structures may include p-n junctions to form diodes for photovoltaic cells, metal oxide semiconductor field-effect transistors (MOSFETs) and thin film transistors (TFTs).

[0020] The substrate processing system 100 is configured to deposit various materials including, but not limited to, dielectric materials, semiconductor materials, and insulating materials on the large area substrate 114 . For example, dielectric and semiconductor materials may include polycrystalline silicon, epitaxial silicon, amorphous silicon, microcrystalline silicon, silicon germanium, silicon oxide, silicon oxynitride, silicon nitride, and combinations or derivatives thereof. . The plasma processing system 100 is further configured to receive therein gases including, but not limited to, precursor gases, purge gases, and carrier gases. For example, the plasma processing system may receive a gaseous species such as hydrogen, oxygen, nitrogen, argon, helium, silane, and combinations or derivatives thereof.

[0021] The substrate processing system 100 includes a substrate processing chamber 102 coupled to a gas source 104 . The substrate processing chamber 102 includes chamber walls 106 that partially define a process volume 110 and a chamber bottom 108 (collectively, a chamber body 101 ). The process volume 110 generally has a sealable slit valve 112 in the chamber walls 106 that enables entry and exit of the substrate 114 into and out of the process volume 110 . accessed through Chamber walls 106 and chamber bottom 108 are generally fabricated from aluminum, aluminum alloys, or other suitable materials for substrate processing. In one embodiment, chamber walls 106 and chamber bottom 108 are coated with a protective barrier material to reduce the effects of corrosion. For example, chamber walls 106 and chamber bottom 108 may be coated with a ceramic material, a metal oxide material, or a rare earth-containing material.

[0022] Chamber walls 106 support lid assembly 116 . A gas distribution plate 126 coupled to the chamber walls 106 or lid assembly 116 is suspended from the backing plate 128 in the substrate processing chamber 102 . A gas volume 140 is formed between the gas distribution plate 126 and the backing plate 128 . The gas source 104 is connected to the gas volume 140 via a gas supply conduit 141 . The gas supply conduit 141 , the backing plate 128 and the gas distribution plate 126 are generally formed of an electrically conductive material and are in electrical communication with each other. In one embodiment, the gas distribution plate 126 and the backing plate 128 are fabricated from a single block of material. The gas distribution plate 126 is generally perforated to evenly distribute the process gases into the substrate processing volume 110 .

[0023] The substrate support 118 is disposed within the substrate processing chamber 102 opposite the gas distribution plate 126 in a generally parallel manner. The substrate support 118 supports the substrate 114 during processing. Generally, the substrate support 118 is made of conductive materials, such as aluminum, and encapsulates at least one temperature control device, which maintains the substrate 114 at a predetermined temperature during processing. to controllably heat or cool the substrate support 118 .

[0024] The substrate support 118 has a first surface 120 and a second surface 122 . The first surface 120 is opposite the second surface 122 . A third surface 121 perpendicular to the first surface 120 and the second surface 122 couples the first surface 120 and the second surface 122 . The first surface 120 supports the substrate 114 . A stem 124 is coupled to the second surface 122 . The stem 124 is an actuator (not shown) that moves the substrate support 118 between an elevated processing position (as shown) and a lowered position that enables substrate transfer in and out of the substrate processing chamber 102 . The substrate support 118 is coupled to the . The stem 124 also provides a conduit for electrical and thermocouple leads between the substrate support 118 and other components of the substrate processing system 100 .

[0025] An RF power source 142 is generally used to create a plasma between the gas distribution plate 126 and the substrate support 118 . The RF power source 142 generates an electric field between the gas distribution plate 126 and the substrate support 118 to form a plasma from the gases present between the gas distribution plate 126 and the substrate support 118 . can do. Various frequencies may be used. For example, the frequency may be from about 0.3 MHz to about 200 MHz, such as about 13.56 MHz. In one embodiment, the RF power source 142 is coupled to the gas distribution plate 126 at the first output 146 via an impedance matching circuit 144 . A second output 148 of the impedance matching circuit 144 is further electrically coupled to the chamber body 101 .

In one embodiment, a remote plasma source (not shown), such as an inductively coupled remote plasma source, may also be coupled between the gas source 104 and the gas volume 140 . Between processing the substrate, a cleaning gas may be provided to a remote plasma source. The cleaning gas may be excited into a plasma in a remote plasma source to form a remote plasma. An excited species generated by a remote plasma source may be provided into the substrate processing chamber 102 to clean the chamber components. The cleaning gas may be further excited by the RF power source 142 to reduce recombination of dissociated cleaning gas species. Suitable cleaning gases include, but are not limited to, _{NF 3} , F ₂ and SF _{6 .}

[0027] One or more grounding straps 130 are electrically connected to the substrate support 118 at the top end 152 of each grounding strap 130 and at the bottom end 154 of each grounding strap 130 at the bottom of the chamber. electrically connected to 108 . In one embodiment, the ground straps 130 are electrically connected to the second surface 122 of the substrate support 118 at the top end 152 . In further embodiments, the ground straps 130 are electrically connected to the third surface 121 at the top end 152 . The substrate processing chamber 102 may include any suitable number of grounding straps for grounding the substrate support 118 to the chamber bottom 108 to form an RF current return path between the substrate support 118 and the chamber bottom 108 . may include arms 130 (five straps are shown in FIG. 1 ). For example, one strap, two straps, three straps, four straps, five straps or more may be used. Ground straps 130 are configured to shorten the path for RF current during processing and to minimize arcing and parasitic plasma near the periphery of substrate support 118 .

[0028] The substrate support 118 includes one or more support connectors 132 coupled to the substrate support 118 . In one embodiment, the one or more support connectors 132 are coupled to the second surface 122 of the substrate support 118 . In further embodiments, the one or more support connectors 132 are coupled to the third surface 121 of the substrate support 118 . Five support connectors are shown in FIG. 1 . However, other quantities of support connectors 132 are also contemplated depending on the number of ground straps 130 utilized.

[0029] Similarly, the chamber bottom 108 includes one or more chamber connectors 134 coupled to the chamber bottom 108 . In other embodiments, one or more chamber connectors 134 are coupled to chamber walls 106 . In FIG. 1 five chamber connectors are shown coupled to the chamber bottom 108 . However, other quantities of chamber connectors 134 are also contemplated depending on the number of ground straps 130 utilized. 1 , each of the ground straps 130 is coupled to a substrate support 118 via a support connector 132 at a top end 152 , and at a corresponding bottom end 154 . It is coupled to the chamber bottom 108 via a chamber connector 134 . The coupling of each ground strap 130 to the support connector 132 and chamber connector 134 forms a ground strap assembly 150 .

[0030] 2 is a side view of an exemplary grounding strap 130 . The body 232 of the grounding strap 130 is generally a rectangular piece of thin flexible aluminum material having a top end 152 and a bottom end 154 with an optional slit 234 at the top end 152 and It is centrally located along the body 232 between the lowermost ends 154 . In one example, grounding strap 130 is further fabricated with one or more folds (not shown) positioned between top end 152 and bottom end 154 . In another example, one or more folds may be formed when the substrate support 118 is raised and lowered between the home position and the processing position during processing to flex the ground strap 130 and form one or more folds. In one embodiment, the grounding strap 130 has a length L of between about 14 inches and about 30 inches, such as between about 18 inches and about 28 inches, such as between about 22 inches and about 24 inches. In one embodiment, the grounding strap 130 has a width W of from about 0.5 inches to about 2 inches, such as from about 1 inch to about 1.5 inches. 2 illustrates an example of a grounding strap 130 suitable for the processing system described herein. Ground strap 130 is generally of any suitable size, shape, and material conducive to substrate processing.

[0031] 3 is a cross-sectional view of a portion 300 of the substrate processing chamber 102 of FIG. 1 . 3 shows three sets of grounding straps 130 coupled to the substrate support 118 by support connectors 132 and further coupled to the chamber bottom 108 by chamber connectors 134 . Ground strap assemblies 150 are illustrated. As shown, each grounding strap assembly 150 includes a single support connector 132 and a single grounding strap 130 coupled to a single chamber connector 134 . However, it is also contemplated that one or more ground straps 130 may be coupled to each support connector 132 and/or each chamber connector 134 . For example, each support connector 132 and/or each chamber connector 134 may be coupled to two ground straps 130 .

[0032] According to one embodiment, each of the support connector 132 and chamber connector 134 includes a first clamp member 362 , 372 and a second clamp member 364 , 374 , respectively. Ground straps 130 are fastened between the first clamp member 362 and the second clamp member 364 of each support connector 132 at the top end 152 and at the bottom end 154 of each chamber. It is fastened between the first clamp member 362 and the second clamp member 364 of the connector 134 . The fastening of the ground straps 130 is achieved through a mechanical clamping force between the first clamp members 362 , 372 and the second clamp members 364 , 374 .

[0033] 4A illustrates the support connector 132 in more detail. In one embodiment, the first clamp member 362 of the support connector 132 is an L-block having a main body 480 and an extension 482 . The contact area is from about 0.5 square inches to about 3 square inches, such as from about 1 square inch to about 2 square inches, depending on the desired capacitance. The main body 480 has a long axis X that is substantially parallel to the second surface 122 of the substrate support 118 . The extension 482 protrudes substantially perpendicular to the long axis X from the upper surface 481 of the main body 480 , the second surface 122 and the second surface 483 on the upper surface 483 of the extension 482 . contact Accordingly, the upper surface 481 of the main body 480 does not directly contact the second surface 122 of the substrate support 118 , and extends 482 from the second surface 122 of the substrate support 118 . ) and placed at the same distance as the height (E). In one embodiment, the upper surfaces 481 and 483 are substantially planar.

Main body 480 further contacts second clamp member 364 on lower surface 485 of main body 480 when fastening ground strap 130 . In one embodiment, the lower surface 485 is substantially planar. In another embodiment, the lower surface 485 includes a planar first portion 431 substantially parallel to the second surface 122 and a second portion oriented _{at an angle α 1 relative to the second surface 122 (} 433). For example, the second portion 433 is oriented _{at an angle α 1 from} about 0 degrees to about 45 degrees with respect to the first portion 431 . In one embodiment, the lower surface 485 further includes a recess (not shown) formed therein, and a protrusion (not shown) formed on the upper surface 487 of the second clamp member 364 . ), or vice versa. Recesses and protrusions formed in the lower surface 485 and upper surface 487 are shaped and sized to receive the dimensions of the grounding strap 130 , such that the grounding strap 130 is more securely fastened by the support connector 132 . create a pocket

In one embodiment, the upper surface 487 of the second clamp member 364 is substantially parallel to the lower surface 485 of the first clamp member 362 . In one embodiment, the upper surface 487 is a planar first portion 435 substantially parallel to the lower surface 485 , and is grounded when the substrate support 118 is raised and lowered between the home position and the processing position. It has a second portion 437 defined by a radial curve to receive the folding of the strap 130 . In other embodiments, the second portion 437 is a planar surface disposed _{at an angle α 2 from} about 0 degrees to about 45 degrees with respect to the first portion 435 . The second clamp member 364 further includes a lower surface 489 facing the chamber bottom 108 . In one embodiment, the lower surface 489 is substantially planar.

[0036] The first clamp member 362 and the second clamp member 364 each include at least one set of fastener holes configured to receive fasteners, such as bolts, screws, or the like. For example, the first clamp member 362 includes a first set of fastener holes 456 configured to receive at least one fastener 466 for coupling the first clamp member 362 to the substrate support 118 . do. The first set of fastener holes 456 are disposed through the extension 482 of the first clamp member 362 and the main body 480 . In one embodiment, the first clamp member 362 further includes a second set of fastener holes 458 aligned with a third set of fastener holes 460 disposed through the second clamp member 364 . . The second and third sets of fastener holes 458 , 460 are configured to receive at least one fastener 468 for coupling the second clamp member 364 to the first clamp member 362 . In one embodiment, the second set of fastener holes 458 are disposed only through the main body 480 of the first clamp member 362 and not the extension 482 . In one embodiment, first clamp member 362 is aligned to receive at least one fastener 468 for coupling first clamp member 362 to substrate support 118 and second clamp member 364 . and configured only one set of fastener holes 458 . The one or more sets of fastener holes described above are disposed near peripheral edges of the first clamp member 362 and the second clamp member 364 such that the fasteners 466 , 468 engage the first clamp member 362 and It does not contact the ground strap 130 fastened between the second clamp members 364 .

4B illustrates the chamber connector 134 in more detail. In one embodiment, each of the first clamp member 372 and the second clamp member 374 of the chamber connector 134 has a long axis X that is substantially parallel to the chamber bottom 108 . In one embodiment, the upper surface 491 of the first clamp member 372 and the lower surface 499 of the second clamp member 374 are substantially planar. In one embodiment, the lower surface 495 of the first clamp member 372 and the upper surface 497 of the second clamp member 374 each have a first portion and a first substantially parallel to the chamber bottom 108 , respectively. and a second portion oriented at an angle with respect to the portion. For example, the lower surface 495 may have a first portion 421 that is substantially parallel, and a second portion 423 oriented _{at an angle β 1 relative to the first portion 421 of about 0 degrees to about 45 degrees.} have Similarly, the upper surface 497 has a first portion 425 that is substantially parallel, and _{a second portion 427 oriented at an angle β 2 from} about 0 degrees to about 45 degrees relative to the first portion 425 . has

[0038] In one embodiment, the lower surface 495 further includes a recess (not shown) formed therein, and matches a protrusion (not shown) formed on the upper surface 497, or vice versa. . Recesses and protrusions formed in the lower surface 495 and upper surface 497 are shaped and sized to receive the dimensions of the grounding strap 130 such that the grounding strap 130 is more securely fastened by the chamber connector 134 . create a pocket It is further contemplated that the chamber connector 134 may be substantially similar in size, shape, and configuration to the support connector 132 .

[0039] Similar to support connector 132 , first clamp member 372 and second clamp member 374 each include at least one set of fastener holes configured to receive fasteners, such as bolts, screws, or the like. For example, the second clamp member 374 includes a first set of fastener holes 446 configured to receive at least one fastener 462 for coupling the second clamp member 374 to the chamber bottom 108 . do. In one embodiment, the second clamp member 374 further includes a second set of fastener holes 448 aligned with a third set of fastener holes 450 disposed through the first clamp member 372 . . The second and third sets of fastener holes 448 , 450 are configured to receive at least one fastener 464 for coupling the second clamp member 374 to the first clamp member 372 . In one embodiment, the second clamp member 374 is aligned to receive at least one fastener 464 for coupling the second clamp member 374 to the chamber bottom 108 and the first clamp member 372 . and only one set of fastener holes 448 configured. The one or more sets of fastener holes described above are disposed near peripheral edges of the first clamp member 372 and the second clamp member 344 such that the fasteners 462 and 464 engage the first clamp member 372 and It does not come into contact with the ground strap 130 fastened between the second clamp members 344 .

[0040] Generally, the components of ground strap assembly 150 are formed of a conductive material such as aluminum, nickel, nickel alloy, or the like. In one embodiment, the first clamp members 362 , 372 and the second clamp members 364 , 374 further include a dielectric coating 490 formed on their desired surfaces. The dielectric coating 490 enables the support connector 132 and/or the chamber connector 134 to function as a capacitor along the current return path provided by the ground strap assembly 150 .

[0041] In one embodiment, a dielectric coating 490 is formed on the surfaces of the support connector 132 and/or the chamber connector 134 , which are in contact with the ground strap 130 to provide a ground between these surfaces. configured to fasten the strap 130 . For example, a dielectric coating 490 is formed on the lower surface 485 of the first clamp member 362 and the upper surface 487 of the second clamp member 364 . Alternatively or additionally, a dielectric coating 490 is formed on the lower surface 495 of the first clamp member 372 and the upper surface 497 of the second clamp member 374 . The dielectric coating 490 may also include, in addition to the surfaces configured to contact the ground strap 130 , the lower surface 489 of the second clamp member 364 and/or the upper surface of the first clamp member 372 ( 491) may be selectively formed. The dielectric coating 490 formed on the lower surface 489 and/or the upper surface 491 may further be utilized to modify the capacitance characteristics of components of the grounding strap assembly 150 .

[0042] The dielectric coating 490 is formed of any suitable dielectric material including, but not limited to, polytetrafluoroethylene (PTFE), polyether ether ketone (PEEK), Teflon, yttrium oxide, and the like. In some embodiments, the dielectric coating 490 is formed by spread coating. In one embodiment, the dielectric coating 490 is formed by anodizing the desired surfaces of the support and chamber connectors 132 , 134 . For example, the dielectric coating 490 may be formed of anodized aluminum.

[0043] In one embodiment, the dielectric coating 490 has a thickness of from about 10 μm to about 100 μm, such as from about 20 μm to about 80 μm, such as from about 40 μm to about 60 μm. For example, the dielectric coating 490 has a thickness of about 50 μm. In one embodiment, the dielectric coating 490 further has a surface roughness value of from about 0 μm to about 5 μm, such as from about 2 μm to about 4 μm. By modifying the thickness and surface roughness of the dielectric coating 490 , the capacitance characteristics of the support connector 132 and chamber connectors 134 are precisely controlled, such that the impedance and ultimately the voltage across the length of the ground strap assembly 150 . It may be possible to correct the potential difference. For example, by reducing the thickness of the dielectric coating 490 formed on the support connector 132 or the chamber connector 134 , the capacitance of the component is increased therein, thereby reducing the total impedance across the ground strap assembly 150 and the substrate. A reduction in the voltage potential difference between the support 118 and the chamber body 108 may result.

[0044] 5 is a cross-sectional view of ground strap assembly 550 . Ground strap assembly 550 is substantially similar to ground strap assembly 150 , but includes two ground straps 130 , 131 coupled together in an overlapping manner by dielectric fastener 592 at junction 596 . include The grounding strap 130 is coupled to the support connector 132 at the top end 152 , and the grounding strap 131 is coupled to the chamber connector 134 at the bottom end 154 . Support connector 132 and chamber connector 134 are substantially similar to the embodiments described above and will include a dielectric coating 490 formed on desired surfaces of support connector 132 and chamber connector 134 . can For example, a dielectric coating 490 is formed on the surfaces of support connector 132 and chamber connector 134 , when clamped therein, in contact with ground straps 130 , 131 .

[0045] In one embodiment, dielectric fastener 592 includes a bolt, screw, etc., and a matching nut for coupling ground straps 130 , 131 therebetween. To secure the grounding straps 130 , 131 relative to each other, two or more plates 594 may further be disposed on opposite sides of the grounding straps 130 , 131 at the junction 597 . Plates 594 may be formed of any suitable metallic material including, but not limited to, stainless steel, aluminum, nickel, and the like. Although depicted as screws or bolts in FIG. 5 , dielectric fasteners 592 are generally any suitable coupling mechanism.

[0046] The dielectric fastener 592 is formed of any suitable dielectric material including, but not limited to, PTFE, PEEK, Torlon, and the like. In one embodiment, dielectric fastener 592 is formed of the same material as dielectric coating 490 . Similar to dielectric coating 490 , dielectric fastener 592 functions as a capacitor along the current return path provided by ground strap assembly 550 . By modifying the thickness of the dielectric fastener 592 and the contact area between the dielectric fastener 592 and the ground straps 130, 131, the capacitance characteristics of the dielectric fastener 592 are precisely controlled, such that the ground strap assembly 550 is may enable further modification of the impedance over the length of In one embodiment, dielectric fastener 592 is utilized as a capacitor, in addition to support connector 132 and/or chamber connector 134 having a dielectric coating 490 formed thereon. In one embodiment, dielectric fastener 592 is utilized as a capacitor in place of support connector 132 and/or chamber connector 134 . Accordingly, the grounding strap assembly 550 may have any combination of capacitors at one or more locations along the grounding strap assembly 550 .

[0047] In the operation of a conventional plasma processing chamber, the substrate support provides a return path for RF power supplied to the gas distribution plate and the substrate support itself, such that a voltage potential difference is created between the substrate support and peripheral interior surfaces of the chamber body. This potential difference inadvertently causes electrical arcing between the substrate support and surrounding surfaces, such as chamber walls. The magnitude of the potential difference and thus the amount of arcing between the substrate support and the chamber walls depends in part on the resistance and size of the substrate support. Arcing is detrimental and causes particle contamination, film deposition fluctuations, substrate damage, chamber component damage, yield loss and system downtime.

[0048] Utilization of ground straps coupled to the substrate support and chamber body provides an alternative RF return path to RF power supplied to the substrate support or gas distribution plate, thereby reducing the likelihood of electrical arcing between the substrate support and the chamber body. . However, conventional ground strap assemblies still provide significant electrical resistance and impedance along the alternative RF return path they are believed to create, creating a voltage potential difference sufficient to cause arcing between the substrate support and the chamber body. formed between the chamber bodies.

[0049] By forming a dielectric layer on the ground strap connectors and utilizing the connectors as capacitors, the voltage potential difference between the substrate support and the chamber body is significantly reduced, thus increasing the RF grounding efficiency. As a result, the reduced voltage potential difference eliminates or reduces arcing between the substrate support and the chamber body.

[0050] Moreover, the reduced voltage potential difference reduces the formation of parasitic plasma during processing. During deposition processes, the plasma generated generally leaks into other parts of the chamber, parasitic to form unwanted films on various chamber components, such as chamber walls, chamber bottom, substrate support and a plurality of ground straps. become plasma. The formation of the parasitic plasma typically occurs between the outer edge of the substrate support or gas distribution plate and the surrounding chamber walls or below the substrate support. Parasitic plasmas are detrimental because such plasmas adversely affect plasma uniformity of thin films deposited on a substrate and can accelerate corrosion of chamber components, such as the ground straps themselves. Thus, reducing or eliminating the formation of parasitic plasma during processing extends the life of the ground straps 130 as well as other chamber components.

[0051] Although the foregoing relates to embodiments of the present disclosure, other and additional embodiments of the disclosure may be devised without departing from the basic scope of the disclosure, the scope of which is set forth in the following claims. is determined by

Claims (15)

A substrate processing chamber comprising:
chamber body - the chamber body comprising:
one or more chamber walls at least partially defining a process volume; and
a chamber bottom coupled to the one or more chamber walls, the chamber bottom coupled to a chamber connector, the chamber connector comprising a first clamping member coupled to a second clamping member by one or more fasteners; Including more-;
a substrate support disposed in the process volume, the support connector coupled to the substrate support, the support connector further comprising a first clamping member coupled to a second clamping member by one or more fasteners; and
A grounding strap having a first end and a second end
includes,
the support connector and/or the chamber, wherein the first end is coupled to the substrate support in the support connector and the second end is coupled to the chamber bottom in the chamber connector and configured to contact the ground strap. a dielectric coating formed on one or more surfaces of the connector;
substrate processing chamber. According to claim 1,
wherein the dielectric coating is formed of anodized aluminum;
substrate processing chamber. According to claim 1,
wherein the dielectric coating is formed of PTFE;
substrate processing chamber. According to claim 1,
wherein the dielectric coating has a thickness of about 10 μm to about 100 μm;
substrate processing chamber. 3. The method of claim 2,
wherein the dielectric coating has a thickness of about 10 μm to about 100 μm;
substrate processing chamber. According to claim 1,
wherein the dielectric coating has a surface roughness of about 0 to about 5 μm;
substrate processing chamber. 3. The method of claim 2,
wherein the dielectric coating has a surface roughness of about 0 to about 5 μm;
substrate processing chamber. According to claim 1,
wherein the dielectric coating is further formed on one or more surfaces of the support connector and/or the chamber connector that are not configured to contact the ground strap.
substrate processing chamber. A ground strap assembly comprising:
a chamber connector having a dielectric coating formed on one or more surfaces of the chamber connector;
a support connector, the support connector having a dielectric coating formed on one or more surfaces of the support connector; and
A grounding strap having a first end and a second end
includes,
wherein the first end is coupled to the support connector and the second end is coupled to the chamber connector, the chamber connector and the support connector functioning as capacitors;
ground strap assembly. 10. The method of claim 9,
wherein the support connector and the chamber connector are formed of aluminum;
ground strap assembly. 11. The method of claim 10,
wherein the dielectric coating is formed of anodized aluminum;
ground strap assembly. 12. The method of claim 11,
wherein the dielectric coating has a thickness of about 10 μm to about 100 μm;
ground strap assembly. 11. The method of claim 10,
wherein the dielectric coating is formed of PTFE;
ground strap assembly. 10. The method of claim 9,
wherein the chamber connector and the support connector each include a first clamping member and a second clamping member coupled together by one or more fasteners;
ground strap assembly. A ground strap assembly comprising:
chamber connector;
support connector; and
A grounding strap having a first end and a second end
includes,
wherein the first end is coupled to the support connector, the second end is coupled to the chamber connector, the first end and the second end of the grounding strap are formed of a dielectric material, the chamber connector and the support connector functions as capacitors at the first end and the second end;
ground strap assembly.

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