Megasonic cleaning with cavity performance monitoring

Abstract

Multiple embodiments of megasonic cleaning chambers are provided herein. In some embodiments, the megasonic cleaning chamber includes a chamber body defining an interior space, a substrate support for supporting a substrate disposed within the interior space, a supply tube including a transparent material configured to direct a cleaning fluid toward the substrate support, a megasonic power generator coupled to the supply tube to provide megasonic power to the cleaning fluid, a megasonic transducer coupled to the megasonic power generator and the supply tube to generate megasonic waves in the cleaning fluid and form cavities in the cleaning fluid, the megasonic transducer configured to direct the megasonic waves and the cavities toward the substrate support, and one or more sensors configured to generate a signal indicative of a characteristic of the cavities in the cleaning fluid.

Description

[Technical field]

[0001] TECHNICAL FIELD

[0001] Embodiments of the present disclosure generally relate to substrate processing apparatus. [Background technology]

[0002]

[0002] Megasonic cleaning chambers are used in the semiconductor industry to clean various types of substrates. Megasonic cleaning chambers generally use acoustic energy to create cavity implosions in a cleaning fluid directed at the substrate. However, large cavities in the cleaning fluid can damage the substrate during cleaning.

[0003]

[0003] Accordingly, the inventors have provided an improved apparatus and method for cleaning a substrate in a megasonic cleaning chamber. Summary of the Invention

[0004]

[0004] Several embodiments of a megasonic cleaning chamber are provided herein. In some embodiments, the megasonic cleaning chamber includes a chamber body defining an interior space, a substrate support for supporting a substrate disposed within the interior space, a supply tube including a transparent material configured to direct a cleaning fluid to the substrate support, a megasonic power generator coupled to the supply tube to provide megasonic power to the cleaning fluid, a megasonic transducer coupled to the megasonic power generator and the supply tube to generate megasonic waves in the cleaning fluid and form cavities in the cleaning fluid, the megasonic transducer configured to direct the megasonic waves and the cavities to the substrate support, and one or more sensors configured to generate a signal indicative of a characteristic of the cavities in the cleaning fluid.

[0005]

[0005] In some embodiments, a method for cleaning a substrate in a megasonic cleaning chamber includes flowing a cleaning fluid toward the substrate through a supply tube in the megasonic cleaning chamber, using a megasonic transducer to generate megasonic waves through the cleaning fluid to form a cavity in the cleaning fluid, and using one or more sensors to identify characteristics of the cavity in situ based on radiation received from the cavity.

[0006] In some embodiments, a non-transitory computer readable medium has stored thereon instructions that, when executed, cause a method of cleaning a substrate in a megasonic cleaning chamber to be performed, the method including flowing a cleaning fluid through a supply tube in the megasonic cleaning chamber toward the substrate, using a megasonic transducer to generate megasonic waves through the cleaning fluid to form a cavity in the cleaning fluid, and using one or more sensors to characterize the cavity in situ based on radiation received from the cavity.

[0007]

[0007] Other and further embodiments of the present disclosure are described below.

[0008]

[0008] The embodiments of the present disclosure, briefly summarized above and described in more detail below, can be understood by reference to the exemplary embodiments of the present disclosure illustrated in the accompanying drawings. However, since the present disclosure may admit of other equally effective embodiments, the accompanying drawings depict only typical embodiments of the present disclosure and therefore should not be considered as limiting the scope. [Brief description of the drawings]

[0009] [Figure 1]

[0009] A schematic side view of a megasonic cleaning chamber according to at least some embodiments of the present disclosure is shown. [Diagram 2]

[0010] FIG. 1 shows a schematic top view of a megasonic cleaning chamber in accordance with at least some embodiments of the present disclosure. [Diagram 3]

[0011] FIG. 1 shows a schematic side view of a megasonic cleaning chamber in accordance with at least some embodiments of the present disclosure. [Figure 4]

[0012] FIG. 1 shows a schematic side view of a megasonic cleaning chamber in accordance with at least some embodiments of the present disclosure. [Diagram 5]

[0013] 1 illustrates a flowchart of a method for cleaning a substrate in a megasonic cleaning chamber in accordance with at least some embodiments of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010]

[0014] To facilitate understanding, the same reference numbers have been used, where possible, to designate identical elements common to the figures. The figures are not to scale and may be simplified for clarity. Elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.

[0011]

[0015] Multiple embodiments of megasonic cleaning chambers are provided herein. The megasonic cleaning chambers provided herein are configured to in situ characterize cavities formed in the cleaning fluid. The cavities may be characterized by characteristics such as size, temperature, energy, shape, and the like. For example, the megasonic cleaning chamber may include one or more sensors to facilitate monitoring the characteristics of the cavities or to facilitate monitoring and controlling the characteristics of the cavities. The megasonic cleaning chamber may include a controller configured to alter one or more parameters of the megasonic cleaning chamber, for example, to control the size, temperature, or energy of the cavities. By controlling the characteristics of the cavities in the cleaning fluid, the megasonic cleaning chamber may advantageously form cavities that are large enough to provide adequate cleaning power and small enough to prevent damage to the substrate being cleaned.

[0012]

[0016] 1 illustrates a schematic side view of a megasonic cleaning chamber or cleaning chamber 100 in accordance with at least some embodiments of the present disclosure. The cleaning chamber 100 generally includes a chamber body 102 defining an interior space 110. The chamber body 102 may be made of any suitable material. A substrate support 116 may be disposed within the interior space 110 for supporting a substrate 112 disposed within the interior space 110. The substrate support 116 may be coupled to a motor 160 to facilitate rotational movement of the substrate support 116. The substrate 112 may be any substrate suitable for use in semiconductor applications.

[0013]

[0017] The cleaning chamber 100 further includes a supply tube 118 disposed within the interior space 110 to direct the cleaning fluid 114 toward the substrate 112. The supply tube 118 is generally made of a transparent material. In some embodiments, the supply tube 118 is made of quartz. In some embodiments, the supply tube 118 is a vertical tube that extends in a direction perpendicular to the top surface of the substrate 112. In some embodiments, the supply tube 118 may extend at an angle less than 90 degrees relative to the top surface of the substrate 112.

[0014]

[0018] In some embodiments, a fluid supply 124 is coupled to the supply tube 118 for holding and supplying the cleaning fluid to the supply tube 118. In some embodiments, the cleaning fluid includes a mixture of liquid and gas. In some embodiments, the cleaning fluid includes a liquid, such as water, ammonium hydroxide, hydrogen peroxide, etc. In some embodiments, the cleaning fluid includes a gas, such as hydrogen (H2), oxygen (O2), helium (He), nitrogen (N2), argon (Ar), or a combination thereof. In some embodiments, the cleaning fluid may include a surfactant. In some embodiments, the fluid supply 124 is coupled to the supply tube 118 through a sidewall of the supply tube 118. A drain system 140 may be coupled to the chamber body 102 for draining the cleaning fluid and contaminants. The drain system 140 may include one or more valves (not shown) for controlling pressure within the interior space 110 and one or more pumps (not shown).

[0015]

[0019] The cleaning chamber 100 includes a megasonic power generator 120 coupled to a supply tube 118 for providing megasonic power to the cleaning fluid 114. In some embodiments, a megasonic transducer 126 is coupled to the megasonic power generator 120 and the supply tube 118 for generating megasonic waves 132 in the cleaning fluid 114. The megasonic waves 132 in the cleaning fluid 114 form cavities 134 in the cleaning fluid 114. The megasonic transducer 126 is configured to direct the megasonic waves 132 and the cavities 134 toward the substrate 112 to clean the substrate 112. In some embodiments, the megasonic waves have a frequency range of about 0.4 MHz to about 6.0 MHz.

[0016]

[0020] The cleaning chamber 100 includes one or more sensors 142 configured to facilitate identifying a characteristic of the cavity 134 in the cleaning fluid 114. For example, the one or more sensors 142 may generate a signal indicative of a characteristic of the cavity 134 or may generate a signal for identifying a characteristic of the cavity 134. In some embodiments, the characteristic of the cavity 134 may be a size of the cavity. In some embodiments, the cleaning chamber 100 further includes a laser source 162 disposed within the interior space 110. In some embodiments, the laser source 162 and the one or more sensors 142 are configured to detect light from the laser source 162 to identify a size of the cavity 134 based on a measured diffraction of the laser beam after the laser beam from the laser source 162 passes through the cavity 134. In some embodiments, the one or more sensors 142 are multiple sensors disposed along a vertical position 164 of the supply tube 118. FIG. 2 illustrates a schematic top view of a portion of the cleaning chamber 100 in accordance with at least some embodiments of the present disclosure. In some embodiments, the sensors 142 are detectors. In some embodiments, multiple sensors 142 are positioned along multiple radial positions along the arcuate path 210 around the supply tube 118. In some embodiments, multiple sensors 142 are positioned approximately halfway around the supply tube 118, or 180 degrees.

[0017]

[0021] 1 , the supply tube 118, the megasonic transducer 126, and the one or more sensors 142 may be collectively referred to as an upper assembly 150. The upper assembly 150 may be configured to translate laterally 156 across the substrate support 116 so that the entire top surface of the substrate 112 may be cleaned. The one or more sensors 142 may be coupled to the supply tube 118 via a mounting frame or other suitable coupling device.

[0018]

[0022] The cleaning chamber 100 may include a controller 170 for controlling the operation of the cleaning chamber 100. The controller 170 generally includes a central processing unit (CPU) 172, a memory 174, and support circuits 176. The CPU 172 may be one of any form of general-purpose computer processor that may be used in an industrial setting. The support circuits 176 are conventionally coupled to the CPU 172 and may include cache, clock circuits, input / output subsystems, power supplies, and the like. Software routines, such as processing methods as described above, may be stored in the memory 174 and, when executed by the CPU 172, transform the CPU 172 into the controller 170. The software routines may also be stored and / or executed by a second controller (not shown) located remotely from the cleaning chamber 100.

[0019]

[0023] During operation, the controller 170 enables data collection and feedback from the cleaning chamber 100 and provides instructions to the system components to optimize performance of the cleaning chamber 100. For example, the controller 170 may be configured to use one or more sensors 142 or signals from one or more sensors 142 to identify a size of the cavity 134 or other characteristic of the cavity and modify one or more parameters of the cleaning chamber 100 to change the size of the cavity 134 or other characteristic of the cavity. The memory 174 may be a non-transitory computer-readable medium having instructions that, when executed by the CPU 172 (or the controller 170), perform the methods described herein.

[0020]

[0024] Embodiments according to the present disclosure may be implemented in hardware, firmware, software, or any combination thereof. Also, embodiments may be implemented as instructions stored using one or more computer-readable media, which may be read and executed by one or more processors. A computer-readable medium may include any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computing platform, or a "virtual machine" running on one or more computing platforms). For example, a computer-readable medium may include any suitable form of volatile or non-volatile memory. In some embodiments, a computer-readable medium may include a non-transitory computer-readable medium.

[0021]

[0025] 3 shows a schematic side view of a megasonic cleaning chamber according to at least some embodiments of the present disclosure. In some embodiments, the cleaning chamber 100 includes a light source 310 directed toward the supply tube 118. The one or more sensors 142 may include a camera 320 having a high-speed imaging sensor configured to capture an image of the cavity 134 illuminated by photons 330 from the light source 310 to determine the size of the cavity 134.

[0022]

[0026] 4 shows a schematic side view of a megasonic cleaning chamber 100 according to at least some embodiments of the present disclosure. In the megasonic cleaning chamber of claim 1, one or more sensors 142 include an optical emission spectrometer 410 to identify the wavelength and intensity of sonoluminescence emission or optical emission spectrum (OES) due to the cavity 134 in the cleaning fluid 114. For example, OES of the gas in the cavity 134. Based on the OES data, characteristics of the cavity such as the cavity temperature, energy, cleaning performance, and tendency to potentially damage the substrate 112 can be estimated. The OES emission from the cavity 134 can be generated by the megasonic wave 132 passing through the cleaning fluid 114.

[0023]

[0027] 5 shows a flow chart of a method 500 for cleaning a substrate in a megasonic cleaning chamber (e.g., cleaning chamber 100) in accordance with at least some embodiments of the present disclosure. At 502, the method 500 includes flowing a cleaning fluid (e.g., cleaning fluid 114) through a supply tube (e.g., supply tube 118) in the megasonic cleaning chamber toward a substrate (e.g., substrate 112).

[0024]

[0028] At 504, the method 500 includes using a megasonic transducer (e.g., megasonic transducer 126) to generate megasonic waves (e.g., megasonic waves 132) through the cleaning fluid to form cavities (e.g., cavities 134) in the cleaning fluid. In some embodiments, the megasonic waves have a frequency range of about 0.4 MHz to about 6.0 MHz.

[0025]

[0029] At 506, method 500 includes using one or more sensors (e.g., one or more sensors 142) to in situ determine a characteristic of the cavity based on radiation received by the one or more sensors from the cavity. A characteristic such as a size of the cavity may be determined from any suitable sensing technique, such as laser diffraction, optical, spectroscopy, or acoustic methods. For example, in some embodiments, using one or more sensors to determine a size of the cavity based on radiation received from the cavity includes directing a laser (e.g., laser source 162) into the delivery tube, detecting scattered laser light (e.g., scattered laser light 148) via one or more sensors, and determining a size of the cavity based on the detected scattered laser light.

[0026]

[0030] In some embodiments, using one or more sensors to determine the size of the cavity includes using an optical method, such as a camera for high speed photography. For example, the optical method may include directing a light source (e.g., light source 310) at the supply tube, using a camera (e.g., camera 320) having one or more sensors configured to generate an image of the cavity, and determining the size of the cavity based on the image. The light source advantageously provides better contrast between the background and the cavity.

[0027]

[0031] In some embodiments, using one or more sensors to identify a characteristic of the cavity based on radiation received from the cavity includes using an optical emission spectrometer (e.g., optical emission spectrometer 520) having one or more sensors configured to detect optical emission from the cavity caused by the megasonic waves to identify, for example, a temperature of the cavity and an energy of the cavity. The temperature of the cavity and the energy of the cavity may refer to the temperature or energy of the gas in the cavity. Based on the data from the optical emission spectrometer, cleaning performance and possible damage can be estimated. In some embodiments, a controller (e.g., controller 170) may obtain OES data from the optical emission spectrometer to identify a size of the cavity based on the OES data.

[0028]

[0032] In some embodiments, the method 500 includes adjusting parameters of the megasonic cleaning chamber if characteristics such as the size of the cavity, the temperature of the cavity, or the energy of the cavity are outside of a desired range. In some embodiments, the parameters include one or more of the power provided by the megasonic power generator to the megasonic transducer, the frequency of the megasonic waves, the gas concentration in the cleaning fluid, or the temperature of the cleaning fluid. For example, if the cavity is too small, one or more of the power provided by the megasonic power generator to the megasonic transducer, the gas concentration in the cleaning fluid, or the temperature of the cleaning fluid can be increased. If the cavity is too large, one or more of the power provided by the megasonic power generator to the megasonic transducer, the gas concentration in the cleaning fluid, or the temperature of the cleaning fluid can be reduced. In some embodiments, the desired range of cavity sizes is from about 1 micron to about 20 microns in diameter. In some embodiments, the parameters can be adjusted via an end user, via a control method using a controller, or via an artificial intelligence (AI) control method based on the use of a controller and data processing using any suitable AI technique.

[0029]

[0033] In some embodiments, the method 500 includes rotating the substrate while flowing the cleaning fluid. In some embodiments, the method 500 includes moving a supply tube over the substrate while flowing the cleaning fluid to clean the entire substrate.

[0030]

[0034] While the forgoing is directed to several embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof.

Claims

1. a chamber body defining an interior space; a substrate support for supporting a substrate disposed within the interior space; a delivery tube comprising a transparent material configured to direct a cleaning fluid towards the substrate support; a megasonic power generator coupled to the supply tube for providing megasonic power to the cleaning fluid; a megasonic transducer coupled to the megasonic power generator and the supply tube to generate megasonic waves in the cleaning fluid and form a cavity in the cleaning fluid, the megasonic transducer configured to direct the megasonic waves and the cavity towards the substrate support; and A megasonic cleaning chamber comprising one or more sensors configured to generate a signal indicative of a characteristic of the cavity in the cleaning fluid.

2. 2. The megasonic cleaning chamber of claim 1, further comprising a laser source disposed within the interior space, the one or more sensors being a plurality of sensors disposed along a vertical position of the supply tube and configured to detect a laser beam from the laser source, and the characteristics of the cavity include a size of the cavity determined based on a measured diffraction of the laser beam.

3. The megasonic cleaning chamber of claim 2 , wherein the plurality of sensors are positioned along a plurality of radial positions around the supply tube.

4. 10. The megasonic clean chamber of claim 1, further comprising a light source directed toward the supply tube, and wherein the one or more sensors are high speed photography sensors configured to capture images of the cavity illuminated by the light source to identify characteristics of the cavity.

5. 10. The megasonic cleaning chamber of claim 1, wherein the one or more sensors are disposed in an optical emission spectrometer configured to determine an optical emission spectrum (OES) emitted by the cavity in the cleaning fluid.

6. The megasonic cleaning chamber of claim 1 , wherein the substrate support is coupled to a motor configured to rotate the substrate support.

7. The megasonic cleaning chamber of claim 1 , wherein the delivery tube is made of quartz.

8. The megasonic cleaning chamber of claim 1 , wherein the supply tube and the one or more sensors are configured to translate across the substrate support.

9. The megasonic cleaning chamber of claim 1 , further comprising a controller configured to use the one or more sensors to identify the characteristic of the cavity in the cleaning fluid.

10. 1. A method of cleaning a substrate in a megasonic cleaning chamber, comprising: flowing a cleaning fluid toward the substrate through a supply tube in a megasonic cleaning chamber; using a megasonic transducer to generate megasonic waves through the cleaning fluid to form cavities in the cleaning fluid; and The method includes using one or more sensors to characterize the cavity in situ based on radiation received from the cavity.

11. 11. The method of claim 10, further comprising adjusting parameters of the megasonic cleaning chamber if the identified cavity characteristics are outside of a desired range.

12. The method of claim 11 , wherein the parameters include one or more of the power provided to the megasonic transducer, the frequency of the megasonic waves, the gas concentration in the cleaning fluid, or the temperature of the cleaning fluid.

13. The method of claim 11 , wherein the specified characteristic is the size of the cavity and the desired range is from about 1 micron to about 20 microns in diameter.

14. using one or more sensors to identify a characteristic of the cavity based on radiation received from the cavity; directing a laser at said delivery tube; detecting scattered laser light via the one or more sensors; and 14. A method according to any one of claims 10 to 13, comprising determining a size of the cavity based on the detected scattered laser light.

15. using one or more sensors to identify a characteristic of the cavity based on radiation received from the cavity; directing a light source at said supply tube; using a camera having the one or more sensors to acquire an image of the cavity; and 14. The method of claim 10, further comprising determining a size of the cavity based on the image.

16. 14. The method of any one of claims 10 to 13, wherein using one or more sensors to identify a characteristic of the cavity based on radiation received from the cavity comprises using an optical emission spectrometer having the one or more sensors configured to detect optical emission from the cavity caused by the megasonic wave.

17. rotating the substrate while passing the cleaning fluid; and 14. The method of claim 10, further comprising moving the supply tube over the substrate while flowing the cleaning fluid.

18. 14. The method of claim 10, wherein the megasonic waves have a frequency range of about 0.4 MHz to about 6.0 MHz.

19. 14. A non-transitory computer readable medium having instructions stored thereon that, when executed, cause a method for cleaning a substrate in a megasonic cleaning chamber as recited in any one of claims 10 to 13 to be performed.

20. 20. The non-transitory computer-readable medium of claim 19, wherein using one or more sensors to identify a characteristic of the cavity based on radiation received from the cavity includes using an optical emission spectrometer having the one or more sensors configured to detect optical emission from the cavity caused by the megasonic wave.

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