Turntable for ultrasonic cleaning and method of using the same

Abstract

The present invention discloses an acoustic cleaning insert. In one example, the acoustic cleaning insert includes a turntable configured to rotate around a central axis. The turntable also includes a platform having an outer periphery. The platform is radially arranged around the central axis. The turntable has an inner ring and an outer ring surrounding the inner ring. A plurality of baffles couple the inner ring and the outer ring to the platform. The plurality of baffles are arranged at predetermined angles around the central axis. The turntable further includes a plurality of retainers. Each retainer is formed by a portion of the platform, a portion of each of the inner ring and the outer ring, and a first side wall and a second side wall formed by a plurality of baffles. The turntable is configured to be immersed in an ultrasonic vibration fluid.

Description

Technical Field

[0001] The present application relates to a carousel for ultrasonically cleaning a workpiece and a method of using the same. Background Art

[0002] Integrated circuits are formed on a substrate by sequentially depositing conductive, semiconductive, or insulating layers. After depositing a layer, the layer is etched to produce circuit features. As a series of layers are sequentially deposited and etched, the outer or uppermost surface of the substrate (i.e., the exposed surface of the substrate) becomes increasingly non-planar. This non-planar outer surface is periodically flattened to provide a relatively flat surface for additional processing. Chemical mechanical polishing (CMP) is a planarization technique. This planarization technique requires the substrate to be mounted on a carrier head or polishing head. The exposed surface of the substrate is placed against a polishing pad. The carrier head provides a controllable load (i.e., pressure) on the substrate to push the substrate against the polishing pad, thereby flattening the non-planar surface of the substrate.

[0003] After any of the CMP operations, the parts of the chemical mechanical polishing tool must be cleaned to remove particles and contaminants from the contaminants. One method of removing contaminants is by immersing one or more parts in a fluid bath and bombarding the parts with sound waves to remove contaminants. The sound waves are generated via a transducer and propagated through the liquid to the parts located in a tank that holds the fluid. The sound waves can cause cavitation near the parts, thereby releasing particles, such as dust and grease, from the parts.

[0004] Conventional acoustic wave cleaners include racks or the like that support CMP parts during cleaning. These racks can attenuate or absorb the energy transmitted by ultrasonic and / or megasonic waves, thereby reducing the effectiveness and efficiency of the acoustic wave cleaner. In addition, the use of racks in conventional cleaners can produce "hot spots", i.e., corrosion or anodization of the surface of the parts. These hot spots are caused by the uneven power density produced by conventional low-frequency transducers. Conventional acoustic wave transducers can produce large bubbles that transfer too much energy to the parts, thereby corroding the surface coating on the CMP parts. In addition, the corners of the tank may attenuate or disperse the sound waves, which can prevent the energy in the sound waves from reaching the parts, resulting in inefficient cleaning of the parts.

[0005] Therefore, there is a need for improved apparatus for cleaning CMP tool components. Summary of the invention

[0006] The present invention discloses an acoustic cleaning insert. In one example, the acoustic cleaning insert includes a turntable configured to rotate around a central axis. The turntable also includes a platform having an outer periphery. The platform is radially arranged around the central axis. The turntable has an inner ring and an outer ring surrounding the inner ring. Multiple partitions couple the inner ring and the outer ring to the platform. The multiple partitions are arranged at predetermined angles around the central axis. The turntable further includes multiple retainers. Each retainer is formed by a portion of the platform, a portion of each of the inner ring and the outer ring, and a first side wall and a second side wall formed by multiple partitions. The turntable is configured to be immersed in an ultrasonic vibration fluid.

[0007] In another example of the present disclosure, an acoustic cleaning system is provided. The acoustic cleaning system includes a tank having an inner surface and an outer surface. The inner surface is configured to contain a liquid capable of propagating acoustic waves. A plurality of acoustic transducers are radially arranged around the inner surface of the tank. The acoustic cleaning system has a turntable configured to rotate around a central axis. The turntable also includes a platform having an outer periphery. The platform is radially arranged around the central axis. The turntable has an inner ring and an outer ring surrounding the inner ring. A plurality of baffles couple the inner ring and the outer ring to the platform. The plurality of baffles are arranged at predetermined angles around the central axis. The turntable further includes a plurality of retainers. Each retainer is formed by a portion of the platform, a portion of each of the inner ring and the outer ring, and a first side wall and a second side wall formed by a plurality of baffles. The turntable is configured to be immersed in an ultrasonic vibration fluid.

[0008] In yet another example, a method for sonic cleaning is disclosed, the method comprising rotating a turntable about a central axis. The turntable is disposed in a tank and further configured to hold a plurality of workpieces. The method further comprises activating a plurality of sonic transducers at a distance from the central axis for ultrasonically vibrating a fluid disposed in the tank. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Therefore, in a manner in which the above-mentioned features of the present disclosure can be understood in detail, a more particular description of the present disclosure briefly summarized above can be obtained by reference to embodiments, some of which are shown in the accompanying drawings. It should be noted, however, that the drawings illustrate only typical embodiments of the present disclosure and are therefore not to be considered limiting of the scope of the present disclosure, as the disclosure may admit to other equally effective embodiments.

[0010] Figure 1 is a schematic side view of an ultrasonic cleaning system in which a rotating disk is disposed.

[0011] Figure 2 Show Figure 1 An isometric view of an example of a turntable is shown in FIG.

[0012] Figure 3 Show Figure 2An isometric view of an alternative example of a turntable shown in FIG.

[0013] Figure 4A yes Figures 1 to 3 A side view of a turntable shown in FIG. 4 having a plurality of holders supporting a plurality of workpieces.

[0014] Figure 4B Yes Figure 4A Bottom view of the turntable shown in .

[0015] Figure 5 is to use Figures 1 to 4B A flow chart of a method for cleaning multiple workpieces on a turntable is shown in FIG. DETAILED DESCRIPTION

[0016] The present invention discloses a turntable for ultrasonically cleaning a CMP workpiece and a method for using the same. The CMP workpiece is a component of a CMP polishing tool, such as a polishing pad. Without limitation, the polishing pad can be a belt pad or a polishing pad, and the workpiece can also be any part of the CMP polishing tool that supports the polishing pad, or a part that needs to be replaced or maintained routinely.

[0017] An ultrasonic cleaner includes a tank filled with a liquid having an ultrasonic transducer configured to generate high frequency waves (e.g., sound waves) that propagate through the liquid. As disclosed herein, one or more workpieces to be cleaned are placed in the liquid in the tank. A turntable holding the one or more workpieces is suspended and rotated within the tank. Thus, the turntable of the present disclosure does not require brackets and other devices disposed within the tank that may reduce cleaning efficiency. Thus, the amount of energy transferred from the waves generated by the ultrasonic transducer is increased by utilizing the fluid within the tank that rotates the turntable. In this way, an increase in cavitation close to the workpiece is achieved.

[0018] High frequency sound waves are generated, for example, by an ultrasonic transducer and propagated through the liquid to the workpiece. The sound waves may cause cavitation adjacent to the workpiece, which releases particles, such as dust and grease, from the workpiece. Advantageously, the rotating turntable disclosed herein reduces energy losses in the tank by reflecting the sound waves toward the workpiece and / or focusing the sound waves on the workpiece, thus improving the efficiency of the ultrasonic cleaning system. It should be understood herein that frequencies from about 18 kHz to about 350 kHz may be considered ultrasonic frequencies, and frequencies above 350 kHz may be considered megahertz ultrasonic frequencies.

[0019] Figure 11 is a schematic side view of an ultrasonic cleaning system 100 in which a turntable 104 is disposed. The ultrasonic cleaning system 100 includes a turntable 104 and a plurality of ultrasonic transducers 132 disposed within a tank 108. The tank 108 has one or more walls 112 having an inner surface 114 and an outer surface 116 opposite the inner surface 114. The tank 108 has a bottom 118 coupled to the one or more walls 112. The bottom 118 is capable of supporting one or more ultrasonic transducers 132. A power source (not shown) provides radio frequency (RF) power to the ultrasonic transducers 132. The tank 108 may be at least partially filled with a liquid 120 that enables the ultrasonic and / or megasonic waves generated by the ultrasonic transducers 132 to propagate. In some examples, the liquid 120 includes deionized water. In some examples, the liquid 120 includes one or more solvents, such as a cleaning solution of standard clean 1 (SC1), a selective deposition removal reagent (SDR), a surfactant, an acid, a base, or any other chemical used to remove contaminants and / or particles from a workpiece (e.g., Figure 2 shown).

[0020] The turntable 104 can be completely immersed in the liquid 120 and surrounded by the liquid 120. Therefore, the turntable 104 can be suspended within the tank 108. For example, a connector 128 or a similar device can suspend the turntable 104 from the support 124. The connector 128 can include various belts, ropes, chains, strings and other flexible linkages. The support 124 can be an overhead beam, a metal rod or a similar support, and the connector 128 can be attached to the support 124. In other examples, other devices such as screws, bolts and couplers can be used to suspend the turntable 104 on the support 124 and / or the connector 128.

[0021] The motor 148 is coupled to the turntable 104 via the connector 128. In one example, the connector 128 is the shaft 216 ( Figure 2 ). The motor 148 is configured to rotate the turntable 104 within the tank 108 at a predetermined angular velocity. The motor 148 can be a DC or AC motor that provides torque to the shaft 216, thereby rotating the turntable 104. The motor 148 can include a rotor, a stator, bearings, windings, and other components such as a commutator. As shown, the motor 148 is adjacent to the support 124, but it should be understood that the motor 148 is not limited to the position and can be positioned anywhere along the connector 128, above the connector 128, or below the connector 128. In some instances, the motor 148 can be immersed in the liquid 120 without departing from the scope of the present disclosure.

[0022] The turntable is in direct contact with the liquid 120 and the connector 128. By suspending the turntable 104 within the tank 108, more energy can be delivered near the turntable 104 to clean the workpiece 252 ( Figure 2 ). For example, more energy in the form of ultrasonic and / or megasonic waves may be used to cavitate the liquid 120 near the rotating disk 104.

[0023] In one example, by positioning the ultrasonic transducer 132 close to the inner surface 114 of the tank 108, the ultrasonic and / or megasonic waves emitted by the ultrasonic transducer 132 can propagate within the tank 108 and release energy near the turntable 104 supporting the workpiece 252. For example, the ultrasonic and / or megasonic waves emitted by the ultrasonic transducer 132 can be reflected from the inner surface 114 toward the turntable 104. Therefore, the ultrasonic and / or megasonic waves generated by the ultrasonic transducer 132 are not attenuated at the corners of the tank 108. In addition, more energy from the ultrasonic and / or megasonic waves is used for cavitation generation. Each ultrasonic transducer 132 is configured to apply energy between about 900 watts and about 1500 watts, such as about 1000 watts or about 1150 watts, to the liquid 120. In another example, each ultrasonic transducer 132 is configured to apply energy between about 1100 watts and about 1350 watts, such as about 1250 watts or about 1300 watts.

[0024] The transducer support 136 connects the ultrasonic transducer 132 to the inner surface 114 of the tank 108. In one example, the transducer support 136 can raise the ultrasonic transducer 132 from the bottom 118 by an offset distance 144 to form a space between the ultrasonic transducer 132 and the bottom 118. The offset distance 144 can be between about 1 inch and about 5 inches, such as about 2 inches or about 4 inches. In some examples, the offset distance 144 is less than about 0.5 inches. In another example, the offset distance 144 is substantially zero (0) so that the ultrasonic transducer 132 is flush mounted with the bottom 118. For example, each ultrasonic transducer 132 can be fixed to the bottom 118 of the tank 108 with a fastener (e.g., a bolt or a screw). Therefore, in some examples, the transducer support 136 can be a fastener for fixing the ultrasonic transducer 132. The space between the ultrasonic transducer 132 and the inner surface 114 of the bottom 118 can mechanically isolate the ultrasonic transducer 132 from the wall 112 and the bottom 118 of the tank 108. In another example, the space between the bottom 118 and the ultrasonic transducer 132 is less than about six inches. However, it should be understood that a larger or smaller space may be used without departing from the scope of the present disclosure.

[0025] When activated, the ultrasonic transducer 132 can generate ultrasonic and / or megasonic waves in the liquid 120. The distance 140 between the ultrasonic transducer 132 and the workpiece 252 and the turntable 104 is determined during the cleaning recipe, as explained in more detail below. The distance 140 includes the vertical (z) and horizontal (x and y) components of each ultrasonic transducer 132. The vertical component and horizontal component of each ultrasonic transducer 132 on the inner surface 114 of the wall 112 and the bottom 118 can be the same. Alternatively, the vertical component and horizontal component between the ultrasonic transducers 132 on the inner surface 114 of the wall 112 and the bottom 118 can be different. In another example, in the case where the inner surface 114 of the tank 108 has a circular circumference, the waves generated by the ultrasonic transducer 132 are reflected from the inner surface 114 to the turntable 104. Therefore, compared with conventional ultrasonic cleaners, more energy is transmitted near the conveyor belt 104. Thus, the ultrasonic transducer 132 disclosed herein increases cavitation of the liquid 120 in the tank 108 proximate the turntable 104 .

[0026] The tank 108 has a perimeter P defined by a radius 150, which is measured from a centerline 152 extending to the inner surface 114 of the tank 108. In one example, one or more ultrasonic transducers 132 are immersed in the liquid 120 by hanging each ultrasonic transducer 132 from a hanger 156 positioned on the tank 108. The hanger 156 is detachably coupled to the ultrasonic transducer 132. Therefore, each ultrasonic transducer 132 has a radial component defined by the radius 150, so that each ultrasonic transducer 132 can be placed at any position along the perimeter P. The radial component can be expressed as an angle θ or an arc length s. For example, if the tank 108 is circular, the perimeter P of the tank 108 is P=2πr, where r is equal to the radius 150. In another example, where the tank 108 is substantially square, the perimeter P is defined as 4*w, where w is equal to the width of one side of the tank 108.

[0027] In other examples, where the tank 108 is not substantially square, the perimeter P is defined as Where m is equal to the number of inner surfaces 114 of the tank 108. In another example, the ultrasonic transducers 132 are arranged at radially equidistant angles r eq Positioning, req≤N / P, where N is the number of ultrasonic transducers 132 and P is the perimeter, as defined above. In yet another example, the ultrasonic transducers 132 are not equidistantly arranged around the inner surface 114 of the tank 108, such that the arc length s is less than the length of the perimeter P and greater than the width of a given ultrasonic transducer 132, allowing for spacing or gaps between adjacent ultrasonic transducers 132. Therefore, the angle θ at which the ultrasonic transducers are arranged is greater than s / r to accommodate the gaps between adjacent ultrasonic transducers 132 and less than 2π.

[0028] Figure 2 Show Figure 1 1 is an isometric view of an example of a turntable 104 shown in FIG. The turntable 104 includes a platform 200 coupled to a carrier 204, and a plurality of support features 256 coupled to the platform 200. The platform 200 has an upper surface 208 and a lower surface 212 opposite the upper surface 208. The carrier 204 extends from the lower surface 212 of the platform 200 in the negative z-axis direction 203. In one example, the shaft 216 rotatable about the central axis 220 is configured to be coupled to the connector 128 ( Figure 1 In another example, the shaft 216 is integral with the connector 128, such as Figure 1 As shown. The shaft 216 is physically coupled to the platform 200 and applies a rotational torque to the shaft 216 when the motor 148 is operated. In one example, the shaft 216 terminates at 208 of the platform 200. Alternatively, the shaft 216 extends through the upper surface 208 and the lower surface 212 of the platform 200, and the shaft 216 remains coupled thereto. In one example, the central axis 220 of the turntable 104 is substantially aligned with the centerline 152 of the tank 108. However, it should be understood that in other examples, the centerline 152 and the central axis 220 may not be aligned without departing from the aspects of the disclosure as described herein.

[0029] The carrier 204 includes a plurality of retainers 224, an inner ring 244, and an outer ring 248. The plurality of retainers 224 extend radially around the central axis 220. Each of the plurality of retainers 224 includes a first sidewall 228 and a second sidewall 232. The first sidewall 228 and the second sidewall 232 each include one or more of the plurality of baffles 222. Each retainer 224 is defined by the lower surface 212 of the platform 200 on one end of the carrier 204. In addition, each retainer 224 is defined by the inner ring 244 and the outer ring 248 on the other end of the carrier 204. The diameter of the inner ring 244 is smaller than the diameter of the outer ring 248 so that the outer ring 248 completely surrounds the inner ring 244. The inner ring 244 and the outer ring 248 are shown as cylindrical rings, but are not limited to the shapes. Each of the inner ring 244 and the outer ring 248 can be formed as a circle, a quadrilateral, or a square.

[0030] In the example shown, the plurality of baffles 222 forming the first sidewall 228 and the second sidewall 232 are formed by rods or bars, which may be made of metal, plastic, polymer, or a combination thereof. For example, the baffles 222 are formed by rods so that the first sidewall 228 and the second sidewall 232 each have an opening between adjacent baffles 222. Each retainer 224 is formed by a substantially quadrilateral arrangement of the baffles 222 so that there are six sides, five of which have openings. The first sidewall 228 and the second sidewall 232 are formed on opposite sides of the quadrilateral arrangement of the baffles 222 and have a maximum opening for each retainer 224. Advantageously, the energy emitted from the transducer 132 has a direct line of sight path to each workpiece 252. In addition, the plurality of baffles 222 minimizes the energy absorbed from the transducer, thereby saving more energy for cavitation generation. The material selected for the plurality of baffles reflects at least one of ultrasonic waves and megasonic waves.

[0031] The slots 240 are defined by spaces or gaps formed between the inner ring 244 and the outer ring 248, each slot 240 having dimensions in the x-axis direction 201 and the y-axis direction 202. The slots 240 are further defined by the first sidewall 228 and the second sidewall 232 extending along the y-axis direction 202. The length of the slot 240 is defined by the inner ring 244 and the outer ring 248 in the xy plane. The xy plane has dimensions in the x-axis direction 201 and the y-axis direction 202. The width of the slot 240 is defined by the distance between the first sidewall 228 and the second sidewall 232. Therefore, in one example, the width of the slot 240 defined by the inner ring 244 is the same as the width of the slot 240 defined by the outer ring 248. In another example, the width of the slot 240 defined by the inner ring 244 is less than the width of the slot 240 defined by the outer ring 248. One or more workpieces 252 are held in the carrier 204 by the plurality of holders 224. Each workpiece 252 is positioned within a slot 240 of the retainer 224. The workpieces 252 extend partially below the plane formed by the inner ring 244 and the outer ring 248 because the space / clearance within the slot 240 enables a portion of the workpiece 252 to extend therethrough.

[0032] The support feature 256 is coupled to the upper surface 208 of the platform 200 and extends from the upper surface 208 in the positive z-axis direction 203 and radially from the central axis 220 in the xy plane. As shown, the support feature 256 extends radially from the shaft 216, and in one example, the support feature 256 is coupled to the shaft 216 and / or the platform 200 by welding. In another example, the support feature 256 is coupled to the shaft 216 and / or the platform 200 by an adhesive or by one or more fixing members (such as bolts, screws or other suitable couplings). It should be understood that the platform 200 and the carrier 204 can be welded or coupled with the fixing members in substantially the same manner as described above.

[0033] Figure 3 Shows Figure 2 2 is an isometric view of an alternative example of a turntable 104 shown in the ultrasonic cleaning system 100 of FIG. The alternative turntable 300 has an axis 216 extending from the upper surface 208 of the platform 200 through to the lower surface 212. The carrier 204 extends from the upper surface 208 of the platform 200 in the positive z-axis direction 203. When the workpieces 252 are disposed in the holder 224, each workpiece 252 rests on the upper surface 208. When the turntable 300 rotates, each slot 240 holds its respective workpiece 252 within the turntable 300 because a portion of each workpiece 252 extends through the opening in the partition 222. The support features 256 extend from the upper surface 208 of the platform 200 in the positive z-axis direction 203 to the axis 216. The support features 256 extend radially from the central axis 220 so that the carrier 204 surrounds the support features 256.

[0034] Figure 4A yes Figures 1 to 3 1, depicting a plurality of holders 224 for supporting a plurality of workpieces 252. The carrier 204 has a height 400 suitable for accommodating each workpiece 252 so that when the carrier 204 is Figure 2 When oriented as shown, a gap 404 is formed between the workpiece 252 and the top of the carrier 204. Alternatively, when the carrier 204 is as shown Figure 3 When oriented as shown, a gap 404 is between the workpiece 252 and the inner and outer rings 244, 248. The slots 240 are configured to retain each workpiece 252 within the holder 224 as the turntable 300 rotates. Thus, each holder 224 has a height 400 and a width that is greater than each workpiece 252. As described above, the slots 240 thereby enable a portion of each workpiece 252 to extend below the carrier 204 between the inner and outer rings 244, 248. By extending a portion of each workpiece 252 beyond the circumference of the carrier 204, the turntable enables a line of sight between each workpiece 252 and one or more ultrasonic transducers 132. Maintaining a line of sight enables efficient cavitation because more energy from the ultrasonic transducer 132 is transferred to the liquid 120 and ultimately cavitation is generated in the liquid 120.

[0035] Figure 4B Yes Figure 4A A bottom view of the plurality of retainers 224 is seen. Figure 4B Yes Figure 4A2. The carrier 204 has an outer diameter 408 sufficient to accommodate each workpiece 252 while enabling a portion of at least one of the workpieces 252 to extend beyond the circumference of the outer ring 248. The inner ring 244 has an inner diameter 412 such that the circumference of the inner ring 244 enables at least an inner portion of the workpiece 252 to extend over the inner ring 244 toward the central axis 220. Extending the workpieces 252 beyond the inner ring 244 and the outer ring 248 in this manner enables the liquid 120 to circulate more efficiently around and through each workpiece 252 because less energy is lost in the liquid after colliding with surfaces of the turntable 104 that are not desired to be cleaned. A plurality of retainers 224 are formed at an angle 420 around the central axis 220 of the carrier 204 such that a gap 416 is formed between each workpiece 252. The gap 416 and the angle 420 are functions of the inner diameter 412 and the outer diameter 408. Thus, the gap 416 and the angle 420 can be optimized to facilitate cleaning of the workpieces 252. In one example, the angle 420 is less than or equal to N / 2π, where N is the number of workpieces 252. In one example, the angle 420 is between about 15 degrees and about 35 degrees, such as about 20 degrees or about 25 degrees.

[0036] Figure 5 is to use Figures 1 to 3 . At operation 504, the plurality of workpieces are rotated in the liquid tank. In one example, the plurality of workpieces 252 are disposed in the turntable 104. The turntable 104 rotates about the central axis 220, thereby causing the workpieces 252 immersed in the liquid 120 to rotate about the central axis 220 of the turntable 104.

[0037] The method 500 proceeds to operation 508 by activating a plurality of acoustic transducers at a distance from the workpiece to ultrasonically vibrate the fluid. In one example, the ultrasonic transducer 132 is positioned at a distance 140 from the workpiece 252. The distance 140 is between about 8 inches and about 36 inches, such as about 12 inches. In another example, the distance 140 is between about 15 inches and about 25 inches, such as about 24 inches or about 20 inches. In yet another example, the distance 140 is less than or equal to about 16 inches or less than about 12 inches, or about 10 inches. As described above, the distance 140 between the ultrasonic transducers 132 mounted to the wall 112 or the bottom 118 of the tank 108 can be equidistant or have different distances. In one example, the distance 140 between each ultrasonic transducer 132 and the central axis 220 of the turntable 104 is equidistant. One advantage is that when the ultrasonic transducer 132 is arranged equidistant from the central axis of the rotating disk 104, the resonant frequency can be achieved more quickly.

[0038] The parameters of the cleaning recipe are adjusted at operation 512. The parameters of the cleaning recipe may include the frequency of the transducer, the power transmitted to the fluid by the transducer, the deoxygenation level of the fluid, the rotation speed of the workpiece, and the duration of the turntable rotation. For example, the ultrasonic transducer 132 receives power from a power supply (not shown) so that the ultrasonic transducer 132 vibrates at a frequency between about 50kHz and about 100kHz, such as about 55kHz. In another example, a plurality of ultrasonic transducers 132 vibrate at a frequency between about 60kHz and about 85kHz, such as about 70kHz. In another example, the ultrasonic transducer 132 vibrates at a frequency between about 75kHz and about 85kHz, such as about 80kHz. With the above frequencies, the size of each cavity or bubble becomes smaller, so that each cavity gives each workpiece 252 less energy. Therefore, the frequencies disclosed above are capable of cleaning each workpiece 252 while reducing the occurrence of hot spots or anodization associated with larger bubbles of conventional ultrasonic cleaners.

[0039] Each ultrasonic transducer 132 is configured to deliver between about 750 Watts and about 1500 Watts of energy to the liquid 120. In one example, the energy delivered to the liquid 120 is between about 850 Watts and about 1350 Watts, such as about 900 Watts or about 950 Watts. In another example, the energy delivered to the liquid 120 is between about 1100 Watts and about 1300 Watts, such as about 1150 Watts, or about 1250 Watts, or about 1275 Watts.

[0040] During cavitation, small vapor-filled cavities may form in the liquid 120, thereby creating cavities, i.e., bubbles or voids, where the pressure in the liquid 120 is relatively low. When the cavities collapse, shock waves are generated near the bubbles extending radially outward from each cavity. The energy from the shock waves removes particles from each workpiece 252. The plurality of baffles 222 enables a greater surface area of ​​each workpiece 252 to be exposed to the liquid 120 so that the energy from the ultrasonic transducer 132 is transferred to cavitation and removes particles from each workpiece 252. The plurality of baffles 222 allows a line of sight to be maintained between at least one of the ultrasonic transducers 132 and substantially every point on the surface of the corresponding workpiece 252. Conventional holders require more surface contact between each workpiece and the conventional holder, thus reducing the energy available for fluid cavitation, and thereby reducing the efficiency and effectiveness of the cleaning process.

[0041] The cleaning recipe includes the oxidation parameters of the fluid. For example, the liquid 120 has an oxygen content of between about 1 ppb and about 20 ppb, such as about 15 ppb. In one example, the oxygen content of the liquid 120 is between about 5 ppb and about 15 ppb, such as about 7 ppb or about 10 ppb. In another example, the oxygen content of the liquid 120 is less than or equal to about 10 ppb, or less than or equal to about 5 ppb.

[0042] The rotation speed of the turntable 104 is between about 5rpm and 50rpm, such as about 15rpm or 20rpm. In another example, the turntable 104 is between about 25rpm and about 40rpm, such as rotating at about 30rpm or about 35rpm. The rotation speed is adjusted to optimize the cleaning of the workpiece 252 by changing the cavitation rate on the surface of each workpiece 252. The turntable 104 can rotate for about 10 minutes to about 60 minutes, such as a duration of about 20 minutes. In another example, the duration of the rotation of the turntable 104 is between about 15 minutes and about 45 minutes, such as about 25 minutes. In another example, the duration is between about 25 minutes and about 35 minutes. In another example, the duration is between about 27 minutes and about 33 minutes, such as about 30 minutes.

[0043] At operation 514, particles from the workpiece are removed by resonating the fluid in the tank. The cleaning recipe may include a resonant mode in which the ultrasonic transducer 132 resonates the liquid 120 at or near the natural frequency of the liquid 120. Resonating the liquid 120 optimizes the rate of energy delivered to each workpiece 252 for cavitation. During the resonance of the liquid 120, more energy is transferred from the ultrasonic transducer 132 to the surface of each workpiece 252. In one example that can be combined with the other examples described above, the shape of the tank 108 is circular. The tank 108 having a circular shape enables energy to be uniformly concentrated on the turntable 104. In addition, the energy reflected from the turntable 104 to the inner surface 114 is redirected back to the center of the tank 108 and the turntable 104. Reflecting energy back to the center of the tank 108 increases the power density of the liquid 120, and thus increases the cavitation rate and / or density of the liquid 120. It should be understood that the shape of the tank 108 is not limited to annular or circular, and the shape can be any shape suitable for holding the liquid 120. Advantageously, however, the circular shape of the tank 108 eliminates dead zones, ie, volumes of fluid where the power density of the fluid is significantly reduced, inhibiting cavitation of the fluid, since the disturbances caused by the acoustic waves in the fluid cancel each other out.

[0044] An optional operation 516 may be performed, in which the cleanliness level of each workpiece is determined. Each workpiece may be tested in a liquid particle counter (LPC) to determine the contamination level of the workpiece. If the cleanliness of each workpiece exceeds a predetermined threshold, the method 500 may terminate. If one or more workpieces do not exceed the predetermined threshold, operation 516 proceeds to operation 504 and the method continues until the workpiece has exceeded the predetermined threshold of cleanliness.

[0045] Disclosed herein are examples of a turntable for ultrasonically cleaning a workpiece, and methods of use thereof. Advantageously, the turntable is utilized to reduce energy losses in the tank by reflecting sound waves toward the workpiece, thereby improving the cleaning efficiency of the ultrasonic transducer. Although the foregoing is directed to specific examples, other examples may be devised without departing from the scope of the present disclosure.

Claims

1. A sonic cleaning insert, include: A turntable, the turntable being configured to rotate about a central axis, the turntable further comprising: a platform having an upper surface and a lower surface opposite to the upper surface, the platform being radially arranged around the central axis; an inner ring and an outer ring at the lower surface of the platform, the outer ring surrounding the inner ring and having a radial opening from the inner ring; a plurality of first baffles and a plurality of second baffles, the plurality of first baffles extending from the inner ring to the upper surface of the platform and being covered by the upper surface of the platform, the plurality of second baffles extending from the outer ring to the upper surface of the platform, wherein the plurality of first baffles and the plurality of second baffles are arranged at predetermined angles around the central axis, The turntable is configured to hold a workpiece covered by the upper surface of the platform, between adjacent first baffles of the plurality of first baffles, and through the radial opening between the inner ring and the outer ring for immersion in the ultrasonic vibration fluid.

2. The sonic cleaning insert of claim 1, include: A rotatable shaft is coupled to the upper surface of the platform, the rotatable shaft being configured to rotate the platform about the central axis.

3. The sonic cleaning insert of claim 2, further comprising: include: A plurality of support features are radially disposed about the central axis, the plurality of support features extending from the rotatable shaft and coupled to the platform.

4. The sonic cleaning insert of claim 1, wherein the turntable is configured to receive a workpiece between adjacent first baffles of the plurality of first baffles.

5. The sonic cleaning insert of claim 1, wherein each of the plurality of first baffles and each of the plurality of second baffles are disposed about the central axis at a predetermined angle, the predetermined angle being proportional to the number of baffles in the plurality of baffles.

6. The sonic cleaning insert of claim 1, further comprising: include: A plurality of support features are radially disposed about the central axis, the plurality of support features extending from a rotatable shaft coupled to the platform surface, wherein each support feature of the plurality of support features is disposed about the central axis at a support angle that is less than or equal to the predetermined angle.

7. A sonic cleaning system, include: a tank having an inner surface and an outer surface, the inner surface being configured to include a fluid capable of propagating sound waves; a plurality of acoustic transducers radially disposed about the inner surface of the tank; and A sonic cleaning insert positioned for insertion into a tank, the sonic cleaning insert comprising: A turntable, the turntable being configured to rotate about a central axis, the turntable further comprising: A platform having an upper surface and a lower surface opposite to the upper surface, the The platforms are radially arranged around the central axis; an inner ring and an outer ring at the lower surface of the platform, the outer ring surrounding the inner ring with radial openings from the inner ring; and a plurality of first baffles and a plurality of second baffles, wherein the plurality of first baffles extend from the inner ring to the upper surface of the platform and are covered by the upper surface of the platform, and the plurality of second baffles extend from the outer ring to the upper surface of the platform, wherein the A plurality of first baffles and the plurality of second baffles are arranged at a predetermined angle around the central axis, wherein the turntable is configured to hold a workpiece, the workpiece being covered by the upper surface of the platform, between adjacent first baffles of the plurality of first baffles, and through an opening between the inner ring and the outer ring for immersion in an ultrasonic vibrating fluid.

8. The sonic cleaning system of claim 7, include: A rotatable shaft is coupled to the upper surface of the platform, the rotatable shaft being configured to rotate the platform about the central axis.

9. The sonic cleaning system of claim 8, further comprising: include: A plurality of support features are radially disposed about the central axis, the plurality of support features extending from the rotatable shaft and coupled to the platform.

10. The sonic cleaning system of claim 7, wherein the tank includes a bottom and wherein the plurality of sonic transducers are located a distance from the bottom.

11. The sonic cleaning system of claim 7, wherein each of the plurality of first baffles and each of the plurality of second baffles is made of a material that reflects at least one of ultrasonic waves and megasonic waves.

12. A method for sonic cleaning using a sonic cleaning system as claimed in any one of claims 7 to 11, include: rotating a turntable about a central axis, the turntable being disposed in the tank, the turntable holding a plurality of workpieces; A plurality of acoustic transducers are activated at a distance from the central axis for ultrasonically vibrating a fluid disposed within the tank.

13. The method for sonic cleaning of claim 12, further comprising: include: Power is provided to vibrate the plurality of acoustic wave transducers at a frequency between about 50 kHz and about 100 kHz.

14. The method for sonic cleaning of claim 12, further comprising: include: The fluid is vibrated at a resonant frequency of the fluid, wherein each acoustic transducer of the plurality of acoustic transducers is located at an equidistant distance from the central axis of the rotating disk.

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