Raised split-ring resonator plasma source

Abstract

A plasma generating device for generating a plasma inside of a chamber includes a base extending along a ground plane. The device further includes a conductive resonator defining a gap and connected to an energy supply, where the gap comprises a width. The device includes at least one support that includes a first end structured to engage the base and an opposing second end structured to support the conductive resonator a distance away from the base. The conductive resonator is structured to generate the plasma at or near the gap and above the base.

Description

Patent ApplicationAttorney Docket No. 3213070W001RAISED SPLIT-RING RESONATOR PLASMA SOURCECROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims priority to, and the benefit of, U.S. Provisional Patent Application Serial No., 63 / 703,252, filed on October 4, 2024. The contents of said application are herein incorporated by reference.TECHNICAL FIELD

[0002] The following disclosure is directed to the field of electrical antennas for igniting and sustaining plasma, and specifically where the electrical antenna is a component of a gas sensor making use of the plasma emission for spectroscopic analysis to determine the nature of a gas mixture. More specifically, aspects of the following disclosure are directed to a split-ring resonator that is supported above the ground plane and structured to operate over a range of high and low pressures.BACKGROUND

[0003] Semiconductor processing tools require ultra clean wafer processing chambers that maintain tight control over a number of gases used or produced during wafer processing. It is important to the operation of the processing tools to accurately measure the makeup of these process gases. Accurate measurement of the process gases aids in optimizing132445295.1Patent ApplicationAttorney Docket No. 3213070W001 process recipes and also provides endpoint control. Another factor in ensuring ultra clean wafer processing is quickly detecting and locating leaks in the semiconductor processing tool. In addition, characterizing backgrounds such as water or hydrocarbon contaminants after periodic maintenance is also important in order to maintain product yield and quality.

[0004] Many semiconductor tools use plasma to facilitate deposition and etch processing. For example, plasma is necessary for most sputter deposition processes and also plays a role in plasma enhanced atomic layer deposition, plasma assisted chemical vapor deposition, and most etch processes. The light emitted directly from these plasmas is sometimes monitored through a window in the process chamber to enable the quality control measurements mentioned above using a method called optical emission spectroscopy (OES). However, it is sometimes desired to monitor gases in the process chamber when the plasma source is not enabled or in chambers where a plasma source is not used, such as buffer / transfer or degas chambers. In other cases, the plasma source may be positioned away from or remote from the process chamber so that only the chemical products enter the process chamber. Consequently, for the above-mentioned situations it is not always possible to use the plasma source of the process chamber to analyze the process gases.

[0005] In some instances, gases and leaks may be monitored with residual gas analyzers based on mass spectrometry. Unfortunately, mass spectrometers require lower pressures for operation than the pressures used during most semiconductor processing. Therefore, to use mass spectrometry, additional pumping is required in order to reduce a sample pressure for analysis. This additional pumping adds costs and slows the response time of the system.232445295.1Patent ApplicationAttorney Docket No. 3213070W001Additionally, the ion-optical lens systems of mass spectrometers are particularly susceptible to damage from many of the film depositions used in building semiconductor devices. Even very thin layers of dielectrics cause charge buildup which degrades spectrometer performance and may prevent the mass spectrometer from working.

[0006] One alternative to either mass spectrometry or monitoring the process plasma is the use of a sensor that provides its own plasma source. Such a sensor may operate in a way that is analogous to the plasma OES measurement described above but can be installed in a chamber where there is no plasma source or can be used during times when the internal plasma source is not operating. Sensors of this type are hereafter referred to as Self Plasma-OES (SP- OES) sensors. (See, for example, US7309842, US7123361, WO10129277A2, US20200273676, and US10262841. See also, https: / / products.inficon.com / en-us / nav-products / product / detail / p- quantus-lplOO / , http: / / www.nanotek.com / eng / products / products.php?ptype=view&prdcode=1608050006&catcod e= 181000&page= 1 &catcode= 181000&searchopt=&searchkey=.)

[0007] These sensors (INFICON Quantus LP-100, Nanotek AEGIS etc...) are able to operate at pressures between about le-3 mbar and about 1 mbar. This pressure range covers some semiconductor processes; however, many process chambers operate above this pressure range during at least some part of the process. For example, important processes like ALD and CVD sometimes operate at 10s of mbar. Creating plasmas at lower pressures takes advantage of a longer mean free path of electrons, for example about 380 pm or more for pressures below 1 mbar, in order to use fairly low electric fields to impart sufficient energy to the electrons to ionize332445295.1Patent ApplicationAttorney Docket No. 3213070W001 the gas molecules, thus creating the desired plasma. For example, the first ionization energy of argon (Ar) is 15.8 eV. Therefore, the electric field must be high enough to impart this much energy to a free electron between collisions with the surrounding gas molecules if the electrons arc going to cause ionization of the argon. This suggests that the electric field required to ionize argon at 1 mbar pressure is 15.8 eV / (e*380 pm), or 41.6 kV / m (where e is the magnitude of the charge on the electron). As the pressure is decreased, the mean path length that the electrons travel between collisions with the background gas increases, and thus the energy that they acquire between collisions for a given electric field increases. Accordingly, lower pressures require lower electric fields to strike a plasma. This also implies that creating plasma at higher pressure typically requires higher electric fields to achieve ionization energies over much shorter mean free paths. For example, ionizing Ar at 50 Torr will require about 2E6 V / m since the mean free path for electrons at this pressure is only about 8 pm, and 15.8 eV is still required to ionize Ar.

[0008] Other resonators have been developed that create an electric field near the resonator gap that is sufficient to ignite and sustain a microplasma in many gases and at pressures ranging from below 1 mbar and up to and slightly above 1000 mbar. There are many potential uses for microplasmas including disinfection and as a controlled light source. In one application the plasma source may be exposed to a process gas in a SP-OES.

[0009] Split-ring resonators, covered with a thin layer of dielectric, such as glass, has been demonstrated to prevent erosion of the ring. Under certain conditions, such as in the monitoring of process gases containing metallic atoms, these currently used resonators suffer from deposition of metal onto the dielectric. This changes the electrical properties of the resonator such432445295.1Patent ApplicationAttorney Docket No. 3213070W001 as the frequency and quality factor and thus shorten lifespan. Moreover, these currently used resonators are only capable of operating in a fairly restricted pressure range and need to be exchanged for a different resonator when operating in high or low pressures.

[0010] These are just some of the problems associated with Self Plasma-OES sensors currently in use, especially with regards to monitoring semiconductor processing tools.BRIEF SUMMARY OF THE INVENTION

[0011] Aspects of the present disclosure are directed to embodiments of a plasma generating device for generating a plasma inside of a chamber. In some embodiments, the plasma generating device includes a base extending along a ground plane, a resonator defining a gap and connected to an energy supply, wherein the gap comprises a width, and at least one support that includes a first end structured to engage the base and an opposing second end structured to support the resonator a distance away from the base. In some embodiments, the resonator is structured to generate the plasma at or near the gap and above the base.

[0012] In some embodiments of the plasma generating device, the at least one support includes an insulator portion comprised of an insulating material and positioned between the base and the resonator. In some embodiments of the plasma generating device, the at least one support comprises a coupler structured to couple the resonator to the at least one support, wherein the coupler is comprised of an insulating material. In some embodiments of the plasma generating device, the resonator comprises a first resonator portion and a second resonator portion, wherein at least one of the first resonator portion and the second resonator portion are configured to pivot532445295.1Patent ApplicationAttorney Docket No. 3213070W001 relative to each other to change the width of the gap. In some embodiments, the plasma generating device further includes a tuner supported by the base and configured to compensate for a change in resonator capacitance as the width of the gap changes. In some embodiments of the plasma generating device, the tuner is configured to move relative to the base. In some embodiments, the plasma generating device further includes a support shield structured to couple to the at least one support and at least partially surround a portion of the resonator to inhibit metal deposition on the insulation portion. In some embodiments, the plasma generating device further includes at least one magnetic element configured to generate a magnetic field, and wherein the magnetic field is configured to alter a path of electrons to enable the plasma generating device to operate at pressures from less than about 10 mTorr to over 100 Torr. In some embodiments of the plasma generating device, the connection between the energy supply and the resonator occurs via the at least one support.

[0013] Aspects of the present disclosure are directed to embodiments of a system for analysis of a gas. In some embodiments, the system includes a chamber comprising a plurality of sides that define a chamber interior. In some embodiments, the system includes a plasma generating device comprising a base positioned on one of the plurality of sides and extending along a ground plane, a conductive resonator defining a gap and connected to an energy supply, wherein the gap comprises a width, and at least one support that includes a first end structured to engage the base and an opposing second end structured to support the conductive resonator a distance away from the base. In some embodiments, the system includes an optical member hermetically sealed to one of the plurality of chamber sides. In some embodiments of the system, the conductive632445295.1Patent ApplicationAttorney Docket No. 3213070W001 resonator is structured to generate the plasma at or near the gap and above the base.

[0014] In some embodiments of the system, the at least one support includes an insulator portion comprised of an insulating material and positioned between the base and the conductive resonator. In some embodiments, the position of the at least one support structure acts as an RF filter and is structured to minimize the out of band hamionics from an RF energy source and the plasma. In some embodiments, the harmonic content will be at integer multiples of the fundamental and the filter can minimize these effects. The positioning of the supports is about 1 / 4 wavelength of the 2nd harmonic which is approximately 1 / 8 of the fundamental frequency. In some embodiments, the system further includes an analyzer configured to receive and analyze light emitted through the optical member and determine a presence of a gas based on the analysis of the light. In some embodiments of the system, the resonator includes a first resonator portion and a second resonator portion, wherein at least one of the first resonator portion and the second resonator portion are configured to pivot relative to the other to change the width of the gap. In some embodiments, the system further includes a tuner configured to be supported by the base and to compensate for a change in resonator capacitance as the width of the gap changes. In some embodiments, the tuner is configured to compensate for low mechanical precision or tolerances in manufacturing components of the device / system. In some embodiments, the system further includes a support shield structured to couple to the at least one support and at least partially surround a portion of the resonator. In some embodiments of the system, the support shield and the conductive resonator are comprised of a same material. In some embodiments, the system further includes at least one magnetic element in cooperation with the plasma generating device732445295.1Patent ApplicationAttorney Docket No. 3213070W001 and configured to generate a magnetic field to alter a path of electrons to enable the plasma generating device to operate at pressures from about less than 10 mTorr to over 100 Torr of nitrogen. Aspects of the present disclosure arc directed to embodiments of a method of manufacturing a plasma generating device. In some embodiments, the method includes structuring a base to extend along a ground plane, structuring a resonator to define a gap comprising a width and to connect to an energy source, and structuring at least one support to include a first end structured to engage the base and structuring an opposing second end s to support the resonator a distance away from the base. In some embodiments, the method includes structuring the resonator to generate the plasma at or near the gap and above the base.

[0015] In some embodiments, the method further includes structuring a support shield to couple to the at least one support and at least partially surround a portion of the resonator. In some embodiments, the method further includes structuring the resonator to comprise a first resonator portion and a second resonator portion and structuring at least one of the first resonator portion and the second resonator portion to pivot relative to each other to change the width of the gap. In some embodiments, the method further includes structuring a tuner to be supported by the base and to compensate for a change in resonator capacitance as the width of the gap changes as well as compensation for mechanical errors and changes in the conductive resonator that develop through use, such as erosion at the tip ends of the conductive resonator. In some embodiments, the method further includes structuring at least one magnetic element to generate a magnetic field to alter a path of electrons to enable the plasma generating device to operate at pressures from below about 10 mTorr to over 100 Torr.832445295.1Patent ApplicationAttorney Docket No. 3213070W001BRIEF DESCRIPTION OF DRAWINGS

[0016] A more particular description of the invention briefly summarized above may be had by reference to the described embodiments, some of which are illustrated in the accompanying drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments. Thus, for further understanding of the nature and objects of the invention, references can be made to the following detailed description, read in connection with the drawings.

[0017] FIG. 1 illustrates a top view of an embodiment of a plasma generating device.

[0018] FIG. 2A illustrates a top view of an embodiment of a plasma generating device.

[0019] FIG. 2B illustrates a close up, enlarged illustration of a portion of the embodiment of FIG. 2A.

[0020] FIG. 3 illustrates a perspective view of an embodiment of a resonator of a plasma generating device.

[0021] FIG. 4A illustrates a side view of the embodiment of FIG. 2A.

[0022] FIG. 4B illustrates an enlarged close-up view of a portion of the embodiment of FIG. 4A.

[0023] FIG. 5 illustrates a sectional view of the embodiment of 2A taken along line932445295.1Patent ApplicationAttorney Docket No. 3213070W001A-A.

[0024] FIG. 6 illustrates a perspective view of an embodiment of a plasma generating device with four resonator supports.

[0025] FIG. 7A illustrates an upside-down perspective view of an embodiment of a resonator support shield.

[0026] FIG. 7B illustrates a top plan view of the embodiment of FIG. 7A.

[0027] FIG. 8 illustrates a top plan view a plasma generating device with a power extension.

[0028] FIG. 9 illustrates an enlarged, close-up view of a portion of the embodiment of FIG. 8.

[0029] FIGS. 10A-D illustrate embodiments of a resonator structured to adjust a width of the resonator gap.

[0030] FIG. 11 illustrates a top perspective view of an embodiment of the plasma generator with a plurality of conductive elements.

[0031] FIG. 12 illustrates a close-up perspective view of a portion of the resonator with one or more lock members.

[0032] FIG. 13 illustrates a top plan view of an embodiment of a plasma generating device with a tuner.

[0033] FIG. 14 illustrates a sectional view of another embodiment of a tuner for a plasma generating device.

[0034] FIG. 15 schematically illustrates an embodiment of a system for analysis of1032445295.1Patent ApplicationAttorney Docket No. 3213070W001 a process gas.

[0035] FIG. 16 schematically illustrates another embodiment of a system for analysis of a process gas.

[0036] FIG. 17 schematically illustrates another embodiment of a system for analysis of a process gas.

[0037] FIG. 18 illustrates an embodiment of a method for tunning the plasma generating device according to some embodiments of the present disclosure.DETAILED DESCRIPTION OF THE INVENTION

[0038] The following discussion relates to various embodiments of an adjustable raised split-ring resonator plasma source for generation of plasma or microplasma. It will be understood that the herein described embodiments are examples that illustrate certain inventive concepts as detailed herein. To that end, other variations and modifications will be readily apparent to those of sufficient skill. In addition, certain terms are used throughout this discussion in order to provide a suitable frame of reference with regard to the accompanying drawings. These temis such as “upper”, “lower”, “forward”, “rearward”, “interior”, “exterior”, “front”, “back”, “top”, “bottom”, “inner”, “outer”, “first”, “second”, and the like are not intended to limit these concepts, except where so specifically indicated. The terms “about” or “approximately” as used herein may refer to a range of 80%- 125% of the claimed or disclosed value. With regard to the drawings, their purpose is to depict salient features of the adjustable raised split-ring resonator plasma source for generation of plasma or microplasma and are not specifically provided to scale.1132445295.1Patent ApplicationAttorney Docket No. 3213070W001

[0039] Referring to Figs. 1-3, an embodiment of a plasma generating device 100 is shown and may be used to create a high electric field or electromagnetic waves that interact with a surrounding environment to generate a plasma, indicated generally as circlc / cllipsc 400 (FIG. 15). The generated plasma 400 (FIG. 15) serves as a source of light with a spectrum that is dependent, among other things, on the make-up of the gas mixture from which it is generated. Analysis of this spectrum can be used to determine the composition of the surrounding environmental gases. In this way the presence of unwanted gases or vapors in the surrounding environment may be detected.

[0040] In some embodiments, the plasma generating device 100 includes a splitring resonator or conductive resonator (resonator) 110 defining a gap 107 and being comprised of a metal, such as tungsten or nickel, or metal alloy, such as steel, Inconel, or Hastelloy. In some embodiments, the gap 107 in the resonator 110 is the area with the highest radio frequency (RF) field, which causes the plasma generation. In some embodiments, the split ring resonator 110 may further comprise a thickness T (FIG. 4B) of approximately 1mm. In some embodiments, the split ring resonator 110 comprises a thickness T (FIG. 4B) that is less than 1mm. In some embodiments, the split ring resonator 110 may comprise a thickness T (FIG. 4B) greater than 1mm, for example of about 2mm. In some embodiments, the resonator 110 further includes one or more support engagement portions 111 and an RF feed engagement portion 115. In some embodiments, one or more of the support engagement portions 111 and the RF feed engagement portion 115 define an opening I l la, 115a that traverses the thickness of the split ring resonator 110.

[0041] During a process step, metal may deposit onto the resonator 110. The1232445295.1Patent ApplicationAttorney Docket No. 3213070W001 deposition of a metal onto the metal resonator 110 will initially produce little to no change in the electrical properties of the resonator 110. Accordingly, the exposed resonator 110 may be used in an environment where metal deposition is occurring for a much longer period of time than a resonator 110 that is covered or at least partially surrounded by an insulating material. While the term “ring” has been used with reference to certain embodiments of the resonator 110, this term is not meant to be limited to a circular ring but may include all circular and non-circular shaped resonators, such as rectangular, elliptical, and other shapes.

[0042] Referring to FIGS. 1, 2A, 2B, 4A, 4B-6, in some embodiments, the resonator 110 is supported by one or more resonator supports 120 positioned along the resonator 110. In some embodiments, the one or more resonator supports 120 are configured to engage the resonator 110 at the one or more support engagement portions 111 of the resonator 110. In some embodiments, the one or more resonator supports 120 are at least partially received by the opening I l la defined in the support engagement portion 111 of the resonator 110. In some embodiments, the resonator supports 120 are structured to support the resonator 110 a distance D (FIG. 4B) away from a ground plane P formed by a base 102 of the plasma generating device 100, a wall of a process chamber, or a vacuum wall. In some embodiments, the distance or space between the resonator 110 and the base 102 comprises an empty space. In some embodiments, the process chamber 300 (FIGS. 15-17) may comprise a chamber where one or more semiconductor manufacturing processes are performed on a substrate. In some embodiments, the process chamber may be kept at a pressure during operation that differs from atmospheric pressure. In some embodiments, the base 102 is formed as part of a flange that is structured to be part of a wall of a1332445295.1Patent ApplicationAttorney Docket No. 3213070W001 process chamber 300 (FIGS. 15-17). In some embodiments, the base 102 defines a first side 101 that is facing the interior 301 (FIGS. 15-17) of a chamber 300 (FIGS. 15-17) or chamber environment and an opposing side 103 that faces away from the chamber interior 301 (FIGS. 15- 17) or chamber environment. In some embodiments, the first side 101 of the base 102 further includes a groove 104 that surrounds the resonator 110 and is dimensioned to at least partially accept a seal member, such as an O-ring.

[0043] Referring to FIGS. 2A, 2B, 4 and 5, in some embodiments, the one or more resonator supports 120 are preferably positioned as far from the gap 107 as possible while still performing their supportive function. In some embodiments, the one or more supports are positioned along the conductive resonator 110 at about 1 / 4 wavelength of the 2nd harmonic, which is approximately 1 / 8 of the fundamental frequency. In some embodiments, the one or more resonator supports 120 may each include a support extension 121 and an insulator portion 122 positioned between the base 102 and the resonator 110. In some embodiments, the insulator portion comprises a dielectric spacer or washer that is coupled to or fits at least partially around the support extension 121. In some embodiments, the support extension 121 includes an end 121a that is structured to engage with the base 102. In some embodiments, a coupler 126 or dielectric fastener is configured to couple the resonator 110 to the resonator support 120. In some embodiments, the coupler 126 is structured to couple a second end 121b of the support extension 121 of the resonator support 120 to the resonator 110. In some embodiments, two or more resonator supports 120 are provided to support the resonator 110. In some embodiments, only a single resonator support 120 is provided. In some embodiments, the insulator portion 122 and the1432445295.1Patent ApplicationAttorney Docket No. 3213070W001 coupler 126 are comprised of an insulating material, such as a ceramic material. In some embodiments, the coupler 126 is comprised of a metal and is isolated from the resonator 110.

[0044] In an embodiment, each of the one or more resonator supports 120 may include a resonator support shield 130 that is positioned to inhibit deposition of metal onto the insulator portion 122 as shown in FIGS. 1, 2 A, 2B, 7 A and 7B. The resonator support shield 130 may be comprised of a similar material as the resonator 110 and is structured to inhibit metal deposition on the insulator portion 122 of the one or more resonator supports 120 during operation. Metal deposition on the insulator would decrease the lifespan of the plasma generating device 100. In an embodiment, the resonator support shield 130 includes a shield body 132. The shield body 132 may include a shield base 134 defining a central opening 138 and a shield wall 136 that is positioned at least partially around the outer periphery of the shield base 132. In operation, the resonator support shield 130 may be positioned such that a portion of the resonator support 120 extends through the central opening 138 and the insulator portion 122 is at least partially surrounded by the shield wall 138. In some embodiments, the resonator support shield 130 comprises a shape that generally conforms to an exterior surface of the insulator portion 122 or dielectric spacer. In some embodiments, the resonator support shield 130 may be structured to at least partially lit around a portion of the resonator 110 without contacting the resonator 110. In some embodiments, the resonator support shield 130 is coupled to the resonator support 120 and does not contact the base 102 or the resonator 110. In addition, in some embodiments, ultraviolet (UV) shields may be used to shield seals, such as O-rings, from UV radiation output by the plasma 400 (FIG. 15).1532445295.1Patent ApplicationAttorney Docket No. 3213070W001

[0045] In some embodiments, an RF feed or a feed pin 150 is generally located away from the gap 107 and is structured to couple the resonator 110 to an energy source 200 (FIGS. 15-17) that is located outside of the chamber 300 (FIGS. 15-17). In some embodiments, the energy source 200 comprises an RF energy source. In some embodiments, the feed pin 150 may directly pass through the base 102 or the chamber wall and to the energy source 200 (FIGS. 15- 17). In another embodiment, the resonator 110 may be positioned away from the feed pin 150 as shown in FIGS. 8 and 9. In these embodiments, a power extension 158 may couple the feed pin 150 to the resonator 110. In some embodiments, similar shields to the resonator support shield 130 may be used to shield at least a portion of the feed pin 150. The RF pin 150 feeds a large amount of energy into the resonator 110 during operation which may cause the resonator 110 to rise to a very high temperature. The high temperature may result in an increased deposition of material onto the resonator 110 (e.g., through a thermal decomposition of gases) and / or warping of the resonator 110, which will decrease the life of the resonator 110. In some embodiments, the high temperature may comprise a range of 200°C-400°C. In some embodiments, the high temperature may comprise a temperature below200°C. Of course, in some embodiments, operating the conductive resonator 110 at a temperature which is too low may result in condensation, which also decreases the life of the plasma generating device 100. In some embodiments, the one or more resonator supports 120 may be structured to remove excess heat from the resonator 110 to inhibit damage to the resonator 110 and extend the resonator life. In some embodiments, at least a portion of each of the one or more resonator supports 120 may be comprised of a high thermally conductive portion 128 (FIG. 4B) to facilitate heat dissipation from1632445295.1Patent ApplicationAttorney Docket No. 3213070W001 the resonator 110. In some embodiments, the high thermally conductive portion 128 (FIG. 4B) is comprised of aluminum nitride. In some embodiments, each of the one or more resonator supports 120 may include one or more high thermal conductivity connections to further facilitate heat dissipation from the resonator 110.

[0046] In some embodiments, the feed pin 150 may comprise a conductive element 152 (FIG. 2A) that electrically couples to the resonator 110. In some embodiments, the feed pin 150 or a portion of the feed pin 150 may be at least partially surrounded or coated with an insulator element 154 (FIGS. 15-17). In FIGS. 15-17, in some embodiments, the feed pin 150 may extend through the base 102 or may extend out from the interior 301 of the process chamber 300 to an exterior of the process chamber, or otherwise through the vacuum wall 303. In an embodiment, the feed pin 150 may directly connect the resonator 110 to the energy source 200, or alternatively as shown in FIGS. 8 and 9, a power extension 158 may be provided so that the resonator 110 may be positioned away from the feed pin 150 that traverses the base 102. This alternative embodiment provides increased flexibility in positioning the resonator 110 regardless of where the energy source 200 may be located. In some embodiments, the power extension 158 may electrically couple to the resonator 110 at a remote pin 159. In some embodiments, the remote pin 159 may be part of a resonator support 120. In some embodiments, the feed pin 150 may be part of a resonator support 120. In some embodiments, the power extension 158 may be structured to be a certain length or to comprise a certain geometry in order to match the power load of the resonator 110 in order to achieve or maintain a high quality factor.

[0047] As used herein, the quality factor is a dimensionless parameter that1732445295.1Patent ApplicationAttorney Docket No. 3213070W001 describes the level at which a resonator is underdamped. The quality factor is defined as a ratio of the initial energy stored in the resonator 110 to the energy lost in one radian of the cycle of oscillation. A higher quality factor indicates a lower rate of energy loss from the resonator 110, which results in a stronger / higher electric field in the gap 107. Accordingly, a higher quality factor is preferred for the plasma generating device 100 because it will result in the plasma generating device 100 being able to generate a plasma over a larger pressure range while consuming less power. Tn some embodiments, a high quality factor is one that is greater than 200.

[0048] The resonator 110 may be operated at a particular frequency where it resonates, for example at 2.45 GHz. The choice of frequency may impact a dimension (i.e., the length, diameter and / or thickness) of the resonator 110. In some embodiments, the size of the resonator 110, as measured from tip to tip, comprises a length of 1 / 2 wavelength at the frequency of interest. In some embodiments, the wavelength of interest depends on the effective dielectric constant, which depends on the composition of the material surrounding the resonator 110 as well as the geometry of the resonator 110. As previously mentioned, in some embodiments the resonator 110 defines a break or gap 107 having a width W spanning a distance between two ends 110a, 110b (FIG. 13) of the resonator 110. In some embodiments of the resonator 110, the width W of the gap 107 may be adjusted so that the plasma generating device 100 may be used over a range of pressures. In some embodiments, the range of pressures is from mTorr to hundreds of Torr. In some embodiments, the range of pressures comprises about 1 mTorr to about 760 Torr. In some embodiments, the range of pressures includes atmospheric pressure.

[0049] Referring to the embodiments of the plasma generating device 100 of FIGS.1832445295.1Patent ApplicationAttorney Docket No. 3213070W00110A-12, the resonator 110 includes a first resonator portion 112 and a second resonator portion 114 that are structured to pivot relative to each about a pivot axis 116 in order to increase or decrease the width W of the gap 107. Increasing the width of the gap enables the plasma generating device 100 to operate at low pressures of about 10 mTorr. In some embodiments, the low the plasma generating device 100 is configured to operate at low pressures below 100 mTorr. The ability to adjust the gap 107 of the resonator 110 avoids a new part having to be made and / or installed for a particular application where only a small number of components are being made. The ability to adjust the width W of the gap 107 decreases operating costs as well as downtime.

[0050] In other embodiments, the movement of the first and / or the second resonator portions 112, 114 may be accomplished by other means, such as by sliding at least one of the first and second resonator portions 112, 114. In some embodiments, the resonator 110 may include two movable resonator portions 112, 114 and a stationary resonator portion 117 (FIG. 9) such that each of the two moveable resonator portions 112, 114 is structured to pivotally couple to the stationary resonator portion 117 (FIG. 9). In some embodiments, the stationary resonator portion 117 (FIG. 9) is electrically coupled to the feed pin 150 (or remote feed pin 159). In some embodiments, the first and second resonator portions 112, 114 are pivotally coupled to the stationary resonator portion 117 (FIG. 9) at corresponding resonator supports 120. In an embodiment, the resonator 110 may only include one moveable resonator portion that pivotally couples to the stationary resonator portion. For example, either the first or the second resonator portion 112, 114 may be structured to move and the other resonator portion comprises the stationary resonator portion. In some embodiments, such as shown in FIGS. 10A-D, the feed pin1932445295.1Patent ApplicationAttorney Docket No. 3213070W001150 is structured to electrically couple to the resonator 110 at an area at or near the pivot axis 116. In some embodiments, the feed pin 150 may electrically couple to the resonator 110 at a stationary resonator portion 117. As shown in the embodiment of FIGS. 10B, 10D, and 12, the first moveable resonator portion 112 may include a first lip 112a and the second resonator portion 114 may include a second lip 114a. In some embodiments, the first lip 112a and the second lip 114a are structured to overlap each other and maintain an RF connection between them as the first and second resonator portions 1 12, 114 pivot relative to each other. In some embodiments, the one or more resonator supports 120 enable pivoting of the first and second resonator portion 112, 114 relative to each other.

[0051] In some embodiments, a lock 140 (FIG. 12) is connected to at least one of the first and second resonator portions 112, 114 and may be structured to define a locked state and an unlocked state where movement of the first and second resonator portions 112, 114 relative to each other is inhibited or permitted, respectively. In some embodiments, the lock 140 includes a first lock member 142 and a second lock member 144 that are structured to move relative to each other. In some embodiments, a portion of the resonator 110 may be positioned in the lock 140. In some embodiments, a portion of the resonator 110 may be positioned between the first and second lock members 142, 144. In some embodiments, when the lock is in the locked state, the first and second lock members 142, 144 exert a compressive force against the portion of the resonator 110. In some embodiments, the portion of the resonator 110 is a portion where one resonator portion pivots relative to another resonator portion. In some embodiments, movement of lock 140 between the unlocked and locked states may be accomplished by moving at least one of the first and second2032445295.1Patent ApplicationAttorney Docket No. 3213070W001 lock members 142, 144 relative to the other. In some embodiments, the lock 140 may include one or more lock surfaces 146 structured to engage a key, which may facilitate movement between the unlocked and locked state. In some embodiments, the first and second lock members 142, 144 may comprise a nut and the key may comprise a wrench. When in the unlocked state, the width W of the gap 107 may be adjusted to be very small, for example on the order of 0.001 inch. In some embodiments, the width W of the gap 107 may be adjusted to be on the order of 0.002 inches. Smaller widths W of the resonator gap 107 are better suited for situations where the resonator 1 10 is used in high pressure environment, such as at or about atmospheric pressure. Alternatively, larger widths W of the resonator gap 107 are better suited for situations where the resonator 110 is used in a low-pressure environment, such as one or more mTorr. Accordingly, the ability of the user to adjust the width of the resonator 110 between uses enables the inventive plasma generator 100 to be used over a wide range of pressures.

[0052] Methods of self-tuning the plasma generating device 100 will now be discussed with reference to FIG. 11. The characteristics of plasma 400 (FIG. 15) generated by the plasma generating device 100 are related to the width W of the resonator gap 107 and the pressure of the environment in which the resonator 110 is located. Changing the with of the gap 107 causes a change in the antenna impedance which shifts the resonator frequency. As the width W of the gap 107 is increased by movement of the first and second resonator portions 112, 114 away from each other, the tip-to-tip capacitance of the resonator 110 decreases. The decreased capacitance may result in a change, such as a decrease, in the quality factor of the resonator 110. In order to correct this loss in quality factor or otherwise tune the resonator 110, the plasma2132445295.1Patent ApplicationAttorney Docket No. 3213070W001 generating device 100 is structured such that as the width W of the gap 107 is increased, the first and second resonator portions 112, 114 are brought closer to conductive elements 127. In this manner, the resonator 110 comprises a self-correcting mechanism which acts to correct or maintain the quality factor while maintaining the frequency range of interest can be adjusted to compensate for what would otherwise cause a change in the antenna’s impedance. In some embodiments, moving the first and second resonator portions 112, 114 changes the overlap with the dielectric (more or less) which can increase or decrease the effective dielectric constant experienced by the resonator. This changes its electrical length and adjusts the frequency to compensate for the change from the gap 107

[0053] Some embodiments of the plasma generator 100 include a tuner 160, such as that shown in the embodiments of FIGS. 1, 2A, 13 and 16. In some embodiments, the tuner 160 may be included instead of, or in addition to the self-correcting mechanism previously described. In some embodiments, the tuner 160 includes a tuning member 162 that is positioned on the base 102 or seated in a recess of the base 102. In some embodiments, the tuning member 162 extends along the ground plane P and is generally positioned in the region of the gap 107. In some embodiments, the tuning member 162 may comprise a circular or disk shape. The tuning member 162 defines an opening 164 structured to at least partially accept a tuning adjuster 166. In some embodiments, the tuning adjuster 166 moveably couples the tuning member 162 to the base 102. In some embodiments, the tuner 160 is comprised of a metal or metal alloy and, in an embodiment, may be comprised of the same material as the resonator 110. In some embodiments, the tuning adjuster 166 may permit the tuning member 162 to be moved relative to the resonator2232445295.1Patent ApplicationAttorney Docket No. 3213070W001110 towards one end of the resonator 110a or the other end of the resonator 110b. In some embodiments, the tuning adjuster 166 may facilitate the movement of the tuning member 162 relative to the resonator 110. In some embodiments, the tuning adjuster 166 is configured to define an unlock and lock state of the tuning member 162. When in the unlocked state, the tuning member 162 is able to move relative to the resonator 110 and when in the locked state, the tuning member 162 is inhibited from moving relative to the resonator 110. In this manner, one side of the resonator 110 may be loaded relative to the other side of the resonator 110 in order to maintain a high quality factor when the width of the gap 107 is changed. Once the tuning member 162 is in the desired position, the tuning adjuster 166 may be actuated to lock the tuning member 162 in place.

[0054] Another embodiment of a tuner 170 is shown in FIGS. 14 and 17. In some embodiments, the tuner 170 includes a tuning member 172 that is positioned in the area of the gap 107 and is structured to extend through the base 102. In some embodiments, the tuning member 172 comprises a tuning slug or a tuning extension with a free end 173 that may be adjusted in a direction towards the base 102 or in a direction away from the base 102. In some embodiments, the tuner 170 further includes a housing 174 structured to at least partially accommodate a portion of the tuning member 172 and a biasing member 176 that is coupled to or in contact with the tuning member 172. In some embodiments, The opposing end 175 of the tuning member 172 includes an adjuster 178 that is structured to enable adjustment of the tuning member 172 to move the free end 173 relative to the base 102 and the resonator 110. As shown, the housing 174 is positioned on an opposing side of the base 102 as the resonator 110. A seal member 177 is positioned inside the housing 174 and surrounds a portion of the tuning member 172. In some embodiments, the2332445295.1Patent ApplicationAttorney Docket No. 3213070W001 seal member 177 is a compression seal that is structured to be compressed against the housing 174 by the biasing member 176 to create a hermetic seal. In an embodiment, at least a portion of an outer surface of the tuning member 172 comprises a plurality of threads structured to engage complementary threads on an inner surface of the housing 174. In order to tune the plasma generator 100 using the tuner 170, the adjuster 178 is manipulated or actuated, which moves the free end 173 of the tuning member 172 along the tuning axis X in a direction away from the base 102 and towards the resonator 110 or towards the base 102 and away from the resonator 1 10. The biasing member 176 is structured to exert a biasing force F or a compressive force against the seal member 177 to maintain a hermetic seal between the free end 173 of the tuning member 172 and the adjuster 178 during adjustment of the tuning member 172. Adjustment of the tuning member 172 relative to the resonator 110 acts to tune the resonator 110 in a similar manner as the previously described embodiment of the tuner 160. In some embodiments, the tuner 160, 170 may be replaced when one or more components of the tuner 160, 170 experience wear or failure. In some embodiments, the one or more tuners 160, 170 are configured to enable tuning of both the first and second resonator portions or each side of the conductive resonator 110. In some embodiments one or more tuning elements 160, 170 may be employed to tune the resonant frequency and quality factor as well as to compensate for manufacturing tolerances.

[0055] Referring to FIG. 15, some embodiments, the plasma generating device 100 includes or is used with one or more magnetic elements 180 (FIG. 15), which enable the plasma generating device 100 to operate over a wider pressure range than would normally be possible. Positioning of the one or more magnetic elements 180 in relation to the base 102 alters the electron2432445295.1Patent ApplicationAttorney Docket No. 3213070W001 path, which may enable the plasma generating device 100 to operate over a wide range of pressures. In some embodiments, the one or more magnetic elements 180 cause the electrons to take a longer path, which results in the plasma generating device 100 being able to operate at lower pressures than would normally be possible. In some embodiments, the plasma generating device 100 may operate at pressures from about 100 mTorr to about 1000 Torr. In some embodiments, the one or more magnetic elements 180 enable the plasma generating device 100 to operate at lower pressures (from less than about 10 mTorr to about 100 mTorr). In some embodiments, the one or more magnets 180 may be located opposite the gap 107 (i.e., on an opposite side 103 of the base 102 from the gap 107) or near the gap 107. The one or more magnetic elements 180 may be any size or shape and may generate any strength of magnetic field as may be required. In some embodiments, the size and shape of the one or more magnetic elements 180 may dictate where the one or more magnetic elements 180 are positioned on the opposite side of base 102 from the gap 107. In some embodiments, the one or more magnetic elements 180 are positioned outside the chamber environment (e.g., on the other side of vacuum wall). In some embodiments, the one or more magnetic elements 180 cooperate with the base 102.

[0056] The components of a system for analysis of a process gas including a chamber 300 with the plasma generator will now be described with reference to FIGS. 15-17. As shown, the chamber 300 includes a plurality of chamber walls 303 that each include an inner surface 302 defining an inner chamber space 301 and an outer surface 304 that is not exposed to the environment of the inner chamber space. The interior of the chamber 300 is coupled in a gastight manner to a process chamber (not shown) via a connecting conduit 306. As shown, the2532445295.1Patent ApplicationAttorney Docket No. 3213070W001 plasma generator 100 is positioned on an inner surface 302 of the chamber 300 and includes a resonator 110, such as those previously described that is supported on the base 102 of a flange that is removably coupled to the chamber 300. As previously described, the resonator 110 defines a gap 107 and is supported above the ground plane P by one or more resonator supports 120. An RF feed 150 couples the resonator to an energy source 200 positioned outside of the chamber 300. In operation, the process gas enters the chamber 300 through the connecting conduit 306. The RF feed 150 feeds power to the resonator 110, which generates a plasma 400 at or above the gap 107. The plasma 400 interacts with the process gas in the chamber and emits light 50, which is transmitted through an optical member 308 positioned in one of the chamber walls 303. In some embodiments, the optical member 308 is hermetically sealed to one of the chamber walls. In some embodiments, the optical member 308 is positioned above or below the gap 107. In some embodiments, the optical member 308 comprises a chamber window positioned above the gap 107. In some embodiments, light emitted by the plasma passes through the optical member 308. In some embodiments, the light 50 is then analyzed using an analyzer 75. In some embodiments, the analyzer 75 comprises a light sensor / spectrometer and a composition of process gases are determined or a presence of a particular gas is determined. Some embodiments of the system include the tuner 160, 170. In some embodiments, the optical element 308 may be structured to be removed and replaced if damaged or worn. In some embodiments, the optical element 308 may include a clamping device configured to facilitate installation and removal of the optical element 308.

[0057] An exemplary method 500 of tuning the system will now be described with2632445295.1Patent ApplicationAttorney Docket No. 3213070W001 general reference to FIG. 18. The method begins with providing a system for the analysis of a process gas including a plasma generating device 502, such as those described above and shown in FIGS. 15-17. A standardized sample is introduced into the chamber at step 504. The plasma generating device is operated at step 506 to generate a plasma in the presence of the standardized sample. A measurement is taken at step 508 and compared to an expected result based on the standardized sample. In some embodiments, the measurement includes at least one of: power; frequency; plasma intensity; starting pressure; mass to charge; a physical gap. If the obtained measurement is not within an acceptable range, (e.g., the quality factor is determined to be below the desired level and / or the device is operating at an improper frequency and / or pressure and / or the measured mass to charge does not correspond to the standard sample), then the width of the gap is adjusted and / or the tuner is adjusted at step 510 and the process then reverts back to step 504. The tuning process continues until the depth of the generated curve is maximized (indicating a high quality factor) and the width of the curve indicates that the system is operating in the proper frequency. When the obtained measurement is within an acceptable range, then the tuning process is ended at step 512. Ensuring that the system is operating in the proper frequency is extremely important so as not to run afoul of government regulations and / or government authorizations.

[0058] In some embodiments, the method 500 of tuning the system is not required. In some embodiments, the system is configured to be tuned in air at low power and with the generation of a plasma by connecting the plasma generation device 100 to a diagnostic tool, such as a network analyzer. In some embodiments, the plasma generation device 100 may be tuned while observing the resonance and the quality factor using the network analyzer.2732445295.1Patent ApplicationAttorney Docket No. 3213070W001

[0059] In some embodiments, one or more components of the plasma generating devices disclosed may be formed using an HTCC process disclosed in U.S. Appl. Publication 2024 / 0047178 and then laser cut. In some embodiments, one or more components of the plasma generating devices disclosed may be comprised of a metal, for example stainless steel and / or tungsten. The metal used will depend on the conditions and manner in which the device is operated. In some embodiments, one or more of the components of the plasma generating devices disclosed are formed from a material capable of being photoetched, laser cut, and / or milled.

[0060] While the present invention has been particularly shown and described with reference to certain exemplary embodiments, it will be understood by one skilled in the art that various changes in detail may be effected therein without departing from the spirit and scope of the invention that can be supported by the written description and drawings. Further, where exemplary embodiments are described with reference to a certain number of elements, it will be understood that the exemplary embodiments can be practiced utilizing either less than or more than the certain number of elements.2832445295.1

Claims

Patent ApplicationAttorney Docket No. 3213070W001CLAIMS1. A plasma generating device for generating a plasma inside of a chamber, comprising, a base extending along a ground plane; a conductive resonator defining a gap and connected to an energy supply, wherein the gap comprises a width; at least one support that includes a first end structured to engage the base and an opposing second end structured to support the conductive resonator a distance away from the base, wherein the conductive resonator is structured to generate the plasma at or near the gap and above the base.

2. The plasma generating device of claim 1, wherein the at least one support includes an insulator portion comprised of an insulating material and positioned between the base and the resonator.

3. The plasma generating device of claim 1 , wherein the at least one support comprises a coupler structured to couple the conductive resonator to the at least one support, wherein the coupler is comprised of an insulating material.

4. The plasma generating device of claim 1, further comprising a tuner supported by the base and configured to compensate for a change in resonator capacitance.

5. The plasma generating device of claim 4, wherein the conductive resonator comprises a first resonator portion and a second resonator portion, wherein at least one of the first resonator portion and the second resonator portion are configured to pivot relative to each other to change the width of the gap.2932445295.1Patent ApplicationAttorney Docket No. 3213070W0016. The plasma generating device of claim 5, wherein the tuner is configured to move relative to the base.

7. The plasma generating device of claim 2, further comprising a support shield structured to couple to the at least one support and at least partially surround a portion of the resonator to inhibit metal deposition on the insulation portion.

8. The plasma generating device of claim 1, further comprising at least one magnetic element configured to generate a magnetic field, and wherein the magnetic field is configured to alter a path of electrons to enable the plasma generating device to operate at pressures below about 10 mTorr.

9. The plasma generating device of claim 1, wherein the connection between the energy supply and the conductive resonator occurs via the at least one support.

10. A system for analysis of a gas, comprising: a chamber comprising a plurality of sides that define a chamber interior; a plasma generating device comprising, a base positioned on one of the plurality of sides and extending along a ground plane, a conductive resonator defining a gap and connected to an energy supply, wherein the gap comprises a width, and at least one support that includes a first end structured to engage the base and an opposing second end structured to support the conductive resonator a distance away from the base; and an optical member hermetically sealed to one of the plurality of chamber sides, wherein conductive resonator is structured to generate the plasma at or near the gap and above the base.3032445295.1Patent ApplicationAttorney Docket No. 3213070W00111. The system of claim 10, wherein the at least one support includes an insulator portion comprised of an insulating material and positioned between the base and the conductive resonator.

12. The system of claim 10, further comprising an analyzer configured to receive and analyze light emitted through the optical member and determine a presence of a gas based on the analysis of the light.

13. The system of claim 10, wherein the conductive resonator comprises a first resonator portion and a second resonator portion, wherein at least one of the first resonator portion and the second resonator portion are configured to pivot relative to each other to change the width of the gap-14. The system of claim 10, further comprising a tuner configured to be supported by the base and to compensate for a change in resonator capacitance.

15. The system of claim 11, further comprising a support shield structured to couple to the at least one support and at least partially surround a portion of the conductive resonator and configured to inhibit metal deposition on the insulation portion.

16. The system of claim 10, wherein the support shield and the conductive resonator are comprised of a same material.

17. The system of claim 10, further comprising at least one magnetic element in cooperation with the plasma generating device and configured to generate a magnetic field to alter a path of electrons to enable the plasma generating device to operate at pressures below about 10 mTorr.

18. A method of manufacturing a plasma generating device, comprising:3132445295.1Patent ApplicationAttorney Docket No. 3213070W001 structuring a base to extend along a ground plane; structuring a conductive resonator to define a gap comprising a width and to connect to an energy source; structuring at least one support to include a first end structured to engage the base and structuring an opposing second end s to support the conductive resonator a distance away from the base; and structuring the conductive resonator to generate the plasma at or near the gap and above the base.

19. The method of claim 18, further comprising structuring a support shield to couple to the at least one support and at least partially surround a portion of the conductive resonator.

20. The method of claim 18, further comprising structuring: the conductive resonator to comprise a first resonator portion and a second resonator portion; and at least one of the first resonator portion and the second resonator portion to pivot relative to each other to change the width of the gap.

21. The method of claim 19, further comprising structuring a tuner to be supported by the base and to compensate for a change in resonator capacitance as the width of the gap changes.

22. The method of claim 18, further comprising structuring at least one magnetic element generate a magnetic field to alter a path of electrons to enable the plasma generating device to operate at pressures below 10 mTorr.

23. The method of claim 18, further comprising positioning of the at least one support along the conductive resonator at approximately 1 / 8 of a fundamental frequency.3232445295.1

Images