Ion implantation system, deposition sensor device for semiconductor manufacturing system and method for detecting depositions in semiconductor manufacturing apparatus

Abstract

An ion implantation system includes sensors for monitoring the deposition of particles or sheets of other materials. The sensors monitor the film thickness on a transparent panel by emitting light and detecting reflections of the light from behind the panel. The system generates a warning for a cumulative thickness. The composition of the film can also be detected by the sensors.

Description

Technical Field

[0001] The present disclosure relates generally to semiconductor manufacturing systems, and more particularly to monitoring deposition on semiconductor manufacturing systems. Cross-reference to related applications

[0002] This application claims priority to U.S. Provisional Application No. 63 / 599,689, filed on November 16, 2023. This prior application is incorporated herein by reference in its entirety for all purposes. Prior Art

[0003] In the manufacture of semiconductor devices, ion implantation is used to dope semiconductors with impurities. Ion implantation systems are typically used to dope workpieces, such as semiconductor wafers, with ions from an ion beam to produce n-type or p-type material doping or to form passivation layers during the manufacture of integrated circuits. This beam processing is typically used to selectively implant the wafer with a designated dopant material at a predetermined energy level and controlled concentration to produce a semiconductor material during the manufacture of integrated circuits. When used to dope semiconductor wafers, the ion implantation system injects a selected ion species into the workpiece to produce the desired foreign material. When implanting ions into silicon wafers, ions generated from source materials such as antimony, arsenic, or phosphorus produce "n-type" foreign material wafers, while "p-type" foreign material wafers are typically produced from ions generated from source materials such as boron, gallium, or indium. When implanting ions into silicon carbide (SiC) wafers, nitrogen (n-dopant) and aluminum (p-dopant) are traditionally used as ion species.

[0004] A typical ion implanter includes an ion source, an ion extraction device, a mass analyzer, with or without a post-acceleration section, a beam transport device, and a wafer processing device. The ion source generates ions with the desired atomic or molecular dopant species. These ions are extracted from the ion source by the ion extraction device, which is typically a set of electrodes that excites and directs the flow of ions from the ion source, thereby forming an ion beam. The desired ions are separated from the ion beam in the mass analyzer, which is typically a magnetic dipole that performs mass dispersion or separation of the extracted ion beam. The beam transport device, which is typically a vacuum system containing a series of focusing and acceleration / deceleration devices, transports the analyzed ion beam to the wafer processing device while maintaining the desired properties of the ion beam. Finally, semiconductor wafers or other target materials for implantation are transported into and out of the wafer processing apparatus via a wafer transport system, which may include one or more robotic arms, for positioning a wafer to be processed in front of the analyzed ion beam and for removing processed wafers from the ion implanter.

[0005] For many ion implantation systems, the ion beam is physically smaller than a target workpiece, so the ion beam is scanned in one or more directions to adequately cover a surface of the target workpiece. Typically, an electrostatic or magnetic beam scanner scans the ion beam in a fast direction, and a mechanical device moves the target workpiece in a slow scan direction to provide adequate coverage of the ion beam across the workpiece surface.

[0006] Ion implantation systems generate unwanted deposits, which can result from liner damage and / or stray particles within certain chambers. Ion implantation systems are highly tuned instruments requiring high precision, and these deposits can hinder or prevent adequate operation. Undesirable tool behavior, such as elevated contaminant particle levels or inadequate surface sealing, can be driven by material deposits on critical parts of the tool.

[0007] Preventive maintenance on ion implanters is typically performed according to a predefined schedule to remove these deposits, for example by cleaning or replacing parts. If preventive maintenance is performed prematurely, the availability of certain tools may be compromised. Conversely, if preventive maintenance is delayed too long, the tool may be unexpectedly unavailable or inferior product may be produced. Either of these situations can lead to manufacturing delays and other problems. Summary of the Invention

[0008] This disclosure provides a system and method for monitoring deposition in the harsh environment of an ion implantation system. Specifically, the monitoring system can be used during operation of the ion implantation system. Deposition within the system can be monitored, and maintenance can be performed when necessary, rather than according to a pre-set maintenance schedule. This improves the uptime of the ion implantation system and avoids unintended degradation in implant quality.

[0009] Therefore, the following is a simplified summary of the present disclosure, intended to provide a basic understanding of certain aspects of the disclosure. This summary is not an extensive overview of the disclosure. It is not intended to identify key or critical elements of the disclosure, nor is it intended to delineate the scope of the disclosure. Its purpose is to present some concepts of the disclosure in a simplified form as a prelude to the more detailed description that follows.

[0010] In one aspect, the disclosure relates to an ion implantation system comprising: an ion source that generates ions and an ion beam along a beam line; a mass analyzer positioned downstream of the ion source that generates a magnetic field based on a selected charge-to-mass ratio and an angle adjustment; a workpiece target associated with the beam line; a controller configured to move the ion beam relative to the workpiece target; and a sensor assembly embedded in a wall of a chamber of the ion implantation system, the sensor assembly comprising a photodetector, a light source, and a transparent panel; the transparent panel comprising an outer surface and an inner surface, the outer surface facing the chamber and the inner surface facing away from the chamber; wherein the photodetector is configured to receive light reflected from deposits on the outer surface of the transparent panel.

[0011] In another aspect, the disclosure relates to a deposition sensor device for a semiconductor manufacturing system, the sensor device comprising: a light detector, a light source, and a transparent panel; the transparent panel comprising an outer surface and an inner surface, wherein the light source is configured to emit light toward the inner surface of the transparent panel, and the light detector is configured to receive light reflected from deposition on the outer surface of the transparent panel.

[0012] In another aspect, the technology described herein relates to a method for detecting deposition in semiconductor manufacturing equipment, comprising: performing an ion implantation, etching, or deposition operation; emitting light toward an inner surface of a transparent panel, the transparent panel having an inner surface and an outer surface; detecting light reflected from a deposition on an outer surface of the transparent panel, the deposition resulting from the ion implantation operation; processing the detected light reflected from the deposition; and sending a warning signal for performing maintenance.

[0013] The above summary is intended only to provide a brief overview of certain features of certain embodiments of the present disclosure, and other embodiments may include additional and / or different features than those mentioned above. In particular, this summary is not intended to limit the scope of the present application. Therefore, to achieve the foregoing and related ends, the present disclosure comprises the features described below and particularly pointed out in the claims. The following description and accompanying drawings set forth in detail certain illustrative embodiments of the present disclosure. However, these embodiments are indicative of some of the various ways in which the principles of the present disclosure may be employed. Other objects, advantages, and novel features of the present disclosure will become apparent from the following detailed description of the disclosure when considered in conjunction with the drawings. Furthermore, unless expressly indicated otherwise, the features of the various embodiments and examples described herein may be combined with one another. Simple diagram description

[0014]

[0014] Figure 1 is a simplified top view illustrating an ion implantation system according to one aspect of the present disclosure.

[0015] [FIG. 2] is a scanning electron microscope (SEM) image and an energy dispersive X-ray spectroscopy (EDX) analysis result of a typical deposited film formed on a test panel.

[0016] [Fig. 3] is a schematic cross-sectional view of an example of a sensor device installed in a chamber of an ion implantation system. [Fig.

[0017] [FIG. 4A] to [FIG. 4C] are schematic cross-sectional views of the sensor device of FIG. 3 as the chamber accumulates deposition during operation.

[0018] [FIG. 5] is a schematic cross-sectional view of an example of a sensor device mounted to a load lock chamber of an ion implantation system.

[0019] [FIG. 6] is a flow chart of an example method for detecting deposition in an ion implantation system.

[0020] [FIG. 7] is a data set showing an example of a collection of data on which a warning can be based.

[0021] [ FIG8 ] shows a top view of a sensor device 800 constructed to test the concepts disclosed herein.

[0022] [FIG. 9A] is a graph showing data collected by measuring a range of visible and infrared light reflected onto a photodetector, which can separate the intensity at each wavelength.

[0023] [FIG. 9B] is a graph showing data collected from a control example, in which five different LED wavelengths of the sensor device of FIG. 8 were reflected from an uncoated quartz transparent panel and measured.

[0024] FIG. 9C and FIG. 9D are diagrams showing test data of the sensor device of FIG. 8 .

[0025] [FIG. 10A] (500 nm thickness) and [FIG. 10B] (1000 nm thickness) demonstrate the accuracy of the sensor with consistent readings at different locations on the sample panel. Implementation Method

[0026] Certain semiconductor manufacturing systems would benefit from monitoring devices to measure and characterize deposition levels, alerting operators when preventative maintenance is urgently needed. Semiconductor manufacturing systems, such as ion implantation systems, contain chambers that are under vacuum and are bombarded by particle streams and other processes during use. Monitoring deposition within these systems is difficult due to the harsh conditions within the chambers.

[0027] The present disclosure is generally directed to various apparatus, systems, and methods related to ion implantation or other semiconductor manufacturing processes in a workpiece. More specifically, the present disclosure is directed to a semiconductor manufacturing system having a deposition monitor and methods for detecting deposition and providing warnings when maintenance is necessary. Ion implantation systems and other semiconductor manufacturing systems, such as etching (e.g., thin film etching) and deposition (e.g., plasma deposition) semiconductor manufacturing systems, may also include the deposition sensors disclosed herein.

[0028] Thus, the technology is described with reference to the drawings, wherein like reference numerals may be used to refer to similar elements throughout. It will be understood that the descriptions of these aspects are for illustrative purposes only and should not be construed in a limiting sense. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the technology described herein. Furthermore, the scope of the present invention is not intended to be limited to the embodiments or examples described below with reference to the accompanying drawings, but is intended to be limited only to the appended claims and their equivalents.

[0029] It should also be noted that the drawings are provided to illustrate embodiments of certain aspects of the present disclosure and are therefore to be considered as examples only. In particular, the elements shown in the drawings are not necessarily to scale with one another, and the placement of the various elements in the drawings is selected to provide a clear understanding of the individual embodiments and is not to be construed as necessarily representing the actual relative positions of the various components for all embodiments encompassed by this disclosure.

[0030] It will also be understood that in the following description, any direct connection or coupling between functional blocks, devices, components, or other physical or functional units shown in the drawings or described herein may also be implemented via an indirect connection or coupling. Furthermore, it is recognized that functional blocks or units shown in the drawings may be implemented as individual features or components in one embodiment, and may also or alternatively be implemented in whole or in part in a common feature or component in another embodiment.

[0031] The use of the terms workpiece and workpiece support herein will recognize that a workpiece will be utilized in an operation, and that a workpiece support is used to support and position the workpiece. Furthermore, ion implantation systems may be manufactured with a workpiece support configured to support a workpiece, without the workpiece support typically being manufactured or sold with the workpiece. Therefore, discussions of the workpiece and how the beam or components of the ion implantation system disclosed herein relate to the workpiece should also be understood as being disclosed in terms of the workpiece support. If a workpiece is in place on the workpiece support, the term workpiece target is used herein to refer to the workpiece, or to a workpiece configured to be held in position by the workpiece support.

[0032] Ion implantation systems, particularly high-dose implanters, generate significant amounts of sputtering from the system's graphite liners, Faraday devices, and apertures. These particles are deposited onto surfaces within the system's chamber or onto the workpiece. These deposits accumulate as films (e.g., see FIG. 2 discussed below), which eventually flake or break off, potentially landing on the workpiece.

[0033] Particles of graphite and photoresist may contribute to the deposited film within the process chamber. Particles of dopants, insulators, and conductors contribute to the deposited film within the beamline area. Particles of feedstock gases and reaction byproducts contribute to the deposited film near the source. As can be seen, after several months of use, approximately 8 microns of deposited film had accumulated on the test silicon wafer.

[0034] During a maintenance procedure, these surfaces can be cleaned or replaced to prevent such flakes from depositing on the workpiece. Preventative maintenance procedures are time-consuming, and the parts to be replaced are expensive. Disclosed herein is a system and method for monitoring deposition in the system and identifying the appropriate time to perform the maintenance procedure. This is an improvement over performing scheduled preventative maintenance, which may occur too early or too late to prevent flakes from depositing on the workpiece. The disclosed monitoring device includes a sensor chamber sealed by a transparent panel that separates the sensor chamber from the ion implantation system's typically vacuum chamber. In one exemplary embodiment, the sensor chamber is not vacuum, allowing for easier maintenance and easier cooling and connection of electrical components. The window is monitored for light reflection to determine the amount of deposition or the thickness of the deposited contaminant coating.

[0035] Ion implantation, in contrast to diffusion, which is a chemical process, is a physical process used in semiconductor device manufacturing to selectively implant dopants into semiconductor workpiece and / or wafer materials. Therefore, implantation does not rely on chemical interactions between the dopant and the semiconductor material. For ion implantation, dopant atoms / molecules are ionized and isolated, sometimes accelerated or decelerated, formed into a beam, and swept across a workpiece or wafer. The dopant ions actually bombard the workpiece, entering the surface and typically resting below the workpiece surface within its lattice structure. The ion beam is unobstructed by any windows or glass. Therefore, analysis and monitoring of deposition on the interior walls of an ion implantation system cannot be accomplished by analyzing the beam or beam path.

[0036] Referring now to the drawings, FIG1 is a schematic diagram of an exemplary ion implantation system 100 according to an aspect of the present disclosure. The system 100 is presented for context and illustration purposes, and it is appreciated that aspects of the present disclosure are not limited to the ion implantation system described, and other suitable ion implantation systems having varying configurations may be employed.

[0037] The system 100 has a terminal 102, a beamline assembly 104, and an end station 106. The terminal 102 includes an ion source 108 powered by a high voltage power supply 110, which generates and directs an ion beam 112 having a selected species to the beamline assembly 104. The ion source 108 generates charged ions, which are extracted and formed into the ion beam 112, which is directed along a beam path in the beamline assembly 104 to the end station 106.

[0038] To generate the ions, a gas containing a dopant material (not shown) to be ionized is located within an ion generation chamber 114 of the ion source 108. The dopant gas may be fed into the ion generation chamber 114, for example, from a gas source (not shown). In addition to the power supply 110, it will be appreciated that one or more suitable mechanisms (not shown) may be used to excite free electrons within the ion generation chamber 114, such as an RF or microwave excitation source, an electron beam injection source, an electromagnetic source, and / or a cathode that generates an arc discharge within the chamber. The excited electrons collide with the dopant gas molecules, thereby generating ions. Typically, positive ions are generated, although the present disclosure is also applicable to systems in which negative ions are generated.

[0039] In this example, the ions are controllably extracted through a slit 116 in the ion generation chamber 114 by an ion extraction assembly 118. The ion extraction assembly 118 includes a plurality of extraction and / or suppression electrodes 120a, 120b. The ion extraction assembly 118 may, for example, include a separate extraction power supply (not shown) to bias the extraction and / or suppression electrodes 120a, 120b to accelerate ions from the ion generation chamber 114. It will be appreciated that because the ion beam 112 includes particles of similar charge, the beam may tend to expand radially outward because the similarly charged particles repel each other. It will also be appreciated that beam expansion can be exacerbated at low energies. Many particles of similar charge (e.g., high current) in a high-current (high-conductivity) beam move relatively slowly (e.g., low energy) in the same direction, resulting in significant repulsive forces between the particles but little momentum to maintain their movement in the direction of the beam path. Therefore, the ion extraction assembly 118 is generally configured such that the beam is extracted at high energies so that the beam does not expand excessively (e.g., so that the particles have sufficient momentum to overcome repulsive forces that could cause beam expansion). Furthermore, in this example, the beam 112 is generally transmitted throughout the system 100 at a relatively high energy and is lowered just before a workpiece 122 held on a workpiece support 175 positioned in the end station 106 to enhance beam containment. The workpiece target in this example is where the workpiece 122 is located or configured to be located on the workpiece support 175.

[0040] In the example of FIG1 , the beamline assembly 104 includes a beam guide 124, a mass analyzer 126, a scanning system 128, and a collimator and / or corrector assembly 130 (generally referred to as a collimator). The mass analyzer 126 performs mass analysis and angular correction / adjustment on the ion beam 112. In this example, the mass analyzer 126 is formed at an angle of approximately 90 degrees and includes one or more magnets (not shown) that act to establish a (dipolar) magnetic field therein. When the beam 112 enters the mass analyzer 126, it is accordingly bent by the magnetic field, causing ions with inappropriate charge-to-mass ratios to be repelled. More specifically, ions with excessively large or low charge-to-mass ratios are deflected into the sidewalls 132 of the mass analyzer 126. In this manner, the mass analyzer 126 primarily permits those ions in the beam 112 having a desired charge-to-mass ratio to pass therethrough and exit through a resolving aperture 134 of a mass resolving aperture assembly 136, details of which will be discussed further below.

[0041] The mass analyzer 126 can perform angular corrections on the ion beam 112 by controlling or adjusting the amplitude of the magnetic dipole field. This adjustment of the magnetic field causes selected ions having a desired / selected charge-to-mass ratio to travel along a different or altered path. Thus, the resolving aperture 134 can be adjusted based on the altered path. In one example, the mass resolving aperture assembly 136 is movable about an X-direction (e.g., a direction transverse to the ion beam 112) to accommodate the altered path through the resolving aperture 134.

[0042] It will be appreciated that collisions of the ion beam 112 with other particles in the system 100 may degrade beam integrity. Accordingly, one or more pumps (not shown) may be included to evacuate at least the beam guide 124 and mass analyzer 126.

[0043] The scanning system 128 in the illustrated example includes a magnetic scanning element 138 and a focusing and control element 140. Respective power supplies 142, 144 are operatively coupled to the magnetic scanning element 138 and the focusing and control element 140, and more specifically to respective electromagnets 146a, 146b and electrodes 148a, 148b located therein.

[0044] The focusing and control element 140 receives the mass-analyzed ion beam 112 having a relatively narrow profile (e.g., a "pencil-tip" beam). A voltage applied to the electrodes 148a and 148b by the power supply 144 operates to focus and control the beam to a scan vertex 150 of the magnetic scanning element 138. A voltage waveform applied to the electromagnets 146a and 146b by the power supply 142 (which can be the same power supply as 144) then scans the beam 112 back and forth in this example, defining a scanned ion beam 152 (sometimes referred to as a ribbon beam) therein. It will be appreciated that the scan vertex 150 can be defined as the point in the optical path from which each beamlet or scanned portion of the ion beam 112 appears to originate after having been scanned by the magnetic scanning element 138.

[0045] The scanned ion beam 112 then passes through the collimator 130, which in the illustrated example comprises two dipole magnets 154a and 154b. The two dipole magnets 154a and 154b are, for example, substantially trapezoidal in shape and oriented in mirror-image relation to each other, thereby bending the beam 112 into a substantially S-shape. In other words, the two dipole magnets 154a and 154b have equal angles and radii, and opposite directions of curvature.

[0046] The parallelizer 130 changes the path of the scanned ion beam 112 so that it travels parallel to a beam axis regardless of the scan angle. Thus, the implantation angle is relatively consistent across the workpiece 122.

[0047] One or more deceleration stages 156 are located downstream of the parallelizer 130 in this example. At this point in the system 100, the ion beam 112 is generally transmitted at a relatively high energy level to mitigate the tendency of the beam to expand, which can be particularly high at elevated beam densities, such as at the scan apex 150. The one or more deceleration stages 156, for example, include one or more electrodes 158a, 158b operable to decelerate the beam 112. The one or more electrodes 158a, 158b typically represent an aperture through which the ion beam 112 travels and can be depicted as straight lines in FIG. 1 .

[0048] However, it will be appreciated that although two electrodes 120a and 120b, electromagnets 146a and 146b, electrodes 148a and 148b, and electrodes 158a and 158b are depicted in the exemplary ion extraction assembly 118, the magnetic scanning element 138, the focusing and control element 140, and the deceleration stage 156, respectively, these elements may include any suitable number of electrodes configured and biased to accelerate and / or decelerate ions and to focus, bend, deflect, converge, diverge, scan, collimate, and / or clean up the ion beam 112, such as disclosed in U.S. Patent No. 6,777,696 to Rathmell et al., the entirety of which is hereby incorporated by reference. Furthermore, the focusing and control element 140 may include electrostatic deflection plates (e.g., one or more pairs thereof), as well as an Einzel lens, a quadrupole, and / or other focusing elements to focus the ion beam.

[0049] The end station 106 then receives the ion beam 112 directed toward the workpiece 122. It is appreciated that different types of end stations 106 can be employed in the ion implantation system 100. For example, a "batch" type end station can simultaneously support multiple workpieces 122 on a rotating workpiece support structure, where the workpieces rotate through a beam path 160 (also known as a beam line) of the ion beam 112 until all workpieces are fully implanted. On the other hand, a "tandem" type end station supports a single workpiece 122 along the beam path 160 for implantation, where multiple workpieces are implanted one at a time in a tandem manner, with each workpiece fully implanted before implantation of the next workpiece begins. In a hybrid system, the workpiece 122 can be mechanically translated in a first direction (the Y direction, or so-called slow scan direction) while the ion beam 112 is scanned in a second direction (the X direction, or so-called fast scan direction) to apply the beam 112 to the entire workpiece 122.

[0050] In one example, a workpiece support 175 is coupled to a mechanical beam-to-workpiece translation system that moves the workpiece 122 relative to the beam 112 in the X-direction, the Y-direction, or both. This is an alternative to a beam-to-workpiece translation system that scans the beam 112 across one or more dimensions of the workpiece 122. As described above, a hybrid system may also be utilized. For the purposes of the presently disclosed technology, whether scanning the beam 112 or moving the workpiece 122, the velocity and positioning of the beam 112 relative to the workpiece 122 (the beam-to-workpiece velocity and position) are of interest.

[0051] The end station 106 in the illustrated example is an inline type end station that supports the single workpiece 122 along the beam path 160 for implantation. For example, a dosimetry system 162 is included in the end station 106, positioned near the workpiece 122 for measurement of the ion beam 112 (e.g., measurement can be performed prior to implantation). During calibration, the beam 112 passes through the dosimetry system 162. The dosimetry system 162, for example, includes one or more analyzers 164 that continuously traverse an analyzer path 166 to measure the profile of the scanned ion beam 152.

[0052] The one or more analyzers 164 may include, for example, a current density sensor, such as a Faraday cup, that measures the current density of the scanned ion beam 152, where the current density is a function of the implantation angle (e.g., the relative orientation between the ion beam and a mechanical surface of the workpiece 122, and / or the relative orientation between the ion beam and a lattice structure of the workpiece). The current density sensor, for example, moves in a substantially orthogonal manner relative to the scanned ion beam 152 and thus generally traverses the width of the scanned ion beam. In one example, the dose measurement system 162 measures both the beam density distribution and the angular distribution.

[0053] A control system 168 (also referred to as a controller) is further configured to control, communicate with, and / or adjust the ion source 108, the mass analyzer 126, the mass-resolving aperture assembly 136, the magnetic scanning element 138, the parallelizer 130, and the dose measurement system 162. The control system 168 may include a computer, microprocessor, or the like, and may be operable to obtain measurements of characteristics of the ion beam 112 and adjust parameters accordingly. The control system 168 may be coupled to the terminal 102 from which the ion beam 112 is generated, as well as the mass analyzer 126 of the beamline assembly 104, the magnetic scanning element 138 (e.g., via power supply 142), the focusing and control element 140 (e.g., via power supply 144), and the deceleration stage 154. Thus, any of these components may be adjusted by the control system 168 to facilitate the desired ion implantation.

[0054] The strength and orientation of the magnetic field generated in the mass analyzer 126 can be adjusted, for example, by adjusting the amount of current flowing through the field windings therein to, for example, change the charge-to-mass ratio of the beam. The implant angle can be controlled by coordinating the mass resolving aperture assembly 136 to adjust the strength or amplitude of the magnetic field generated in the mass analyzer 126. The control system 168 can adjust the magnetic field of the mass analyzer 126 and the position of the resolving aperture 134 based on measurement data, in this example, from the analyzer 164. The control system 168 can verify the adjustments using additional measurement data and, if necessary, perform additional adjustments through the mass analyzer 126 and the resolving aperture 134.

[0055] Although the sensor device disclosed herein is primarily described for use in ion implantation systems, it can also be used in other semiconductor processing equipment. Other semiconductor manufacturing systems include etching and deposition systems. In particular, the sensor device is used in vacuum semiconductor processing chambers to produce long-term films or other deposits.

[0056] The sensor device disclosed herein can be coupled to an equipment chamber, such as a chamber external to the ion implantation system 100. The chamber can be configured to be under vacuum and, during operation, is under vacuum. For example, the sensor device can be coupled to the terminal 102, the beamline assembly 104, and / or the end station 106. Within the end station 106, a dose measurement system 162 is located within a specific area of interest for deposition monitoring. Sputtered particles or deposited flakes can be detected in this area, where the analyzer 164 measures the current density immediately before the beam strikes the workpiece 122.

[0057] Furthermore, the sensor device can be coupled to the ion source 108 chamber. Deposition buildup can be caused by subcomponents of the ion source 108, such as the ion generation chamber 114 and the ion extraction assembly 118. However, monitoring is best performed within the chamber, on an outer wall of the ion source 108 chamber, so the components do not need to be under vacuum.

[0058] Monitoring the sidewalls 132 of the mass analyzer 126 can be useful in eliminating particle flaking and causing problems downstream. In one example, significant problems can be detected by monitoring for sudden changes in these areas, such as the beam striking and etching the sidewalls 132.

[0059] FIG3 is a schematic cross-sectional view of an exemplary sensor device 300. The sensor device 300 is embedded within an opening 315 in a sidewall 305 of a chamber 310 of the ion implantation system. The opening 315 can be formed, for example, by drilling a cylindrical hole in the sidewall 305 of the chamber 310. The chamber 310 can also have other geometries, such as a cube or a frustum of a cone. Exemplary depths and diameters of the opening 315 can range from 0.5 cm to 20 cm, such as from 1 cm to 15 cm or from 2 cm to 8 cm.

[0060] A transparent panel 320 is disposed on one side of the chamber 310. The transparent panel 320 allows light to pass therethrough at a high transmittance, such as 80% or greater, at a 90-degree incidence, such as 90% to 99%, or 93% to 98%. The transparent panel 320 should be of sufficient thickness to allow the reflectance to be detected as discussed below. This thickness can be, for example, 1 cm, or 0.25 to 5 inches, 0.5 to 3 inches, or 0.75 to 1.5 inches. The transparent panel 320 can be made of glass or a transparent polymer. For example, the transparent panel 320 can include one or more of quartz, silica, soda lime, borosilicate, aluminum, lead, soda, barium oxide, thorium oxide, lanthanum oxide, cerium oxide, fluorine, acrylate, polycarbonate, or polyethylene terephthalate.

[0061] In one example, an outer surface 365 of the transparent panel 320 is substantially flush with the sidewall 305 of the chamber 310. A deposited film 370 is formed on the outer surface 365 of the transparent panel 320. The transparent panel 320 is supported by a seal 325. The seal can be a rubber O-ring or some other elastomeric or metallic material with suitable geometry that effectively forms a vacuum seal. The seal 325 seals an inner surface 375 of the transparent panel 320 against the outer surface 365 of the transparent panel 320. The seal 325 contacts an inner wall 330 of the chamber 310 and an inner surface 375 of the transparent panel 320. In other examples, the seal 325 may contact the side of the transparent panel 320 and the sidewall 305 of the chamber 310. The transparent panel 320 is held in place within the chamber 310, for example, by bolting a sealing plate to the chamber 310, as is done with the other ports of the chamber 310. Alternatively, the transparent panel 320 may be held in place within the chamber 310 by being adhered to the sidewalls 305 of the chamber 310. Other mechanisms for retaining the transparent panel 320 within the chamber 310 may also be utilized, for example, a retaining ring may be placed around the outer surface 365 of the transparent panel 320 and adhered or otherwise secured to the sidewalls 305 of the chamber 310.

[0062] In one embodiment, the chamber 310 is under vacuum during operation. The sidewalls 305 can be made of a suitable material, such as aluminum or other metals sufficiently rigid to withstand the vacuum of the chamber 310. As mentioned above, the sensor assembly 300 can be embedded in various chambers of the ion implantation system.

[0063] Behind the transparent panel 320 is a photodetector 335 and a light source 340 within a sensor chamber. The light source 340 can, for example, be an LED array comprising multi-colored LEDs, i.e., LEDs emitting light at different wavelengths. These wavelengths can correspond to one or more of red, blue, and green light in the visible light spectrum. Wavelengths ranging from 620 to 750 nm (red), 450 to 495 nm (blue), and 495 to 570 nm (green) can be used. The light source 340 can also or alternatively emit light in the infrared range, such as 780 to 1500 nm, for example, 790 to 900 nm. In one example, the light source 340 includes multiple LEDs in an array, one dedicated to red, green, blue, and infrared light. Incandescent light or laser light can also be used.

[0064] The photodetector 335 can be, for example, a photodiode, such as a pn, pin, or amalgamated photodiode, or a metal-semiconductor (MSM) photodetector. In one example, the photodetector is capable of detecting multiple colors / wavelengths, including, for example, red, blue, green, and infrared light. In some examples, multiple photodetectors 335 are provided to account for different wavelengths, such as one photodetector 335 for infrared light and one photodetector 335 for visible light. Regardless, the photodetector 335 should be capable of detecting the wavelengths emitted by the light source 340. In this example, the photodetector 335 is a broad-response detector, for example, detecting light within a hemisphere, 50 to 100% of a hemisphere, or 75 to 90% of a hemisphere.

[0065] In another embodiment, the light detector 335 can be located outside the opening 315 and completely outside any wall of the chamber 310. A fiber optic cable can be run from the opening 315, such as where the light detector 335 is depicted, to a light detector 335 located outside the chamber 310. A fiber optic cable can also transmit light and replace the light source 340 shown in the figure. The other end of the fiber optic cable would be coupled to a light source outside the opening 315 and completely outside any wall of the chamber 310.

[0066] In the example sensor device 300 of FIG. 3 , the light detector 335 and the light source 340 are coupled to (eg, mounted on) a backing plate 345 , which is attached to an outer surface 360 of the chamber 310 .

[0067] 3, and in some cases, the light source 340 are in communication with a local processor 350. In other examples, the processor may be remote and coupled via wires.

[0068] The processor 350 processes the signal received from the light detector 335 and transmits information to the user, for example, by providing a simplified signal to a computing device or even directly sending a report to a display screen. Reports or warnings transmitted directly via the computing device or display screen can indicate that maintenance is not required, that maintenance is required within, for example, six months, three months, one month, or immediately. Warnings can also indicate that reflectivity has changed significantly over a short period of time, thereby indicating a serious problem. The processor 350 can also control the light source 340, turning it on and off, and in some cases, regularly pulsing light. Pulsing light can provide better signals and data.

[0069] The photodetector 335 and light source 340 should both be oriented or configured (e.g., using optical fibers) so that light emitted from the light source 340 will strike the outer surface 365 of the transparent panel 320, and at least some reflected light from deposits on the outer surface 365 will be detected by the photodetector 335. In the example of FIG3 , the photodetector 335 and light source 340 are both oriented in the same direction and are immediately adjacent to each other. In other examples, the photodetector 335 and light source 340 can be oriented in different directions, but generally care should be taken to ensure that light directly emitted from the light source does not strike the photodetector 335, thereby overpowering any signal from the reflected light. In one example, a light barrier can be positioned between the photodetector 335 and light source 340 to prevent light directly emitted from the light source from being detected by the photodetector 335.

[0070] 4A-4C depict the operation of the sensor device 300 as the chamber 310 accumulates deposition.

[0071] 4A , the chamber 310 is new or has just been cleaned, and thus has no deposited film 370. Light 380 is emitted from the light source 340. The light 380 travels through the transparent panel 320 and into the chamber 310 without any substantial reflection being detected by the light detector 335.

[0072] In FIG4B , the chamber 310 has been in use for some time, for example, 0.5 to 2 months, and has accumulated a deposit of a deposited film 370. The light 380 now strikes the deposit on the outer surface 365 of the transparent panel 320, and some reflected light 385 is reflected back toward the light detector 335. This depicts a situation where there is some deposit, but not enough to signal a need for maintenance, cleaning, or replacement.

[0073] In FIG4C , the chamber 310 has been in use for a longer period of time, such as 3 to 12 months, and deposits of the deposited film 370 continue to accumulate on the outer surface of the transparent panel 320. More light 380 now strikes the deposits on the outer surface 365 of the transparent panel 320, and thus more reflected light 385 is reflected back toward the light detector 335. This depicts a situation where there is significant enough deposit to signal the need for maintenance cleaning or replacement.

[0074] In another example, shown in FIG5 , a sensor device 500 is used in a load lock chamber 510. The load lock chamber 510 is a preparation chamber used to depressurize the atmosphere surrounding a workpiece before loading it into a processing chamber (or terminal) where implantation occurs. No ion beam is operated in this chamber 510. Deposition that occurs in this chamber 510 is typically silicon dust particles that enter the chamber when the gate is open and the pressure differential creates turbulence.

[0075] In FIG5 , a photodetector 535 and light source 540 pair are positioned side-by-side beneath a transparent panel floor 520 of the load lock chamber 510. The photodetector 535 and light source 540 are coupled to a processor 560, which may be local or remote. The processor 560 may provide simplified signals to a main processor for the ion implanter and / or control the emission, sensing, and alarm processes discussed above.

[0076] In an alternative approach, rather than using a photodetector positioned behind a transparent panel to detect light reflected from deposits on the outer surface of the panel, reflections from the deposits can be detected from the top of the deposits as they reflect light within the chamber. For example, the light source can project light through the chamber onto a target on one side of the chamber, and a photodetector can detect the reflected light on the other, adjacent side of the chamber. In this example, a clean sample chamber will reflect a higher amount of light than a chamber with deposits on it. The deposits will cause the light to be less reflective. For example, the light source can illuminate light from one adjacent side of the chamber onto a target area on the side of the chamber, and a photodetector on the other adjacent side (the side of the chamber opposite the light source) can be configured to detect the reflected light.

[0077] Referring now to Figure 6, methods associated with the sensor apparatus used in the ion implantation system will be further described. Figure 6 is a flow chart of an exemplary method for detecting deposition in an ion implantation system.

[0078] At operation 610, after assembly of the sensor assembly within a chamber of the ion implantation system, ion implantation operations such as those described above in a system such as that shown in FIG. 1 are performed. Typically, operations can continue for several months without maintenance.

[0079] At operation 620, light is emitted toward an inner surface of a transparent panel having an inner surface and an outer surface. The transparent panel can be mounted flush with the side of a process chamber (as shown in FIG. 3 ) or on a glass floor (as shown in FIG. 5 ). As discussed above, the light can be emitted by an LED array. The light can be multi-colored and / or infrared.

[0080] At operation 630, light reflected from a deposit on an outer surface of the transparent panel resulting from an ion implantation operation is detected. Before initial operation of the ion implantation system or after maintenance, all or a substantial amount of the emitted light from the sensor will be transmitted through the transparent panel and thus not reflected back for detection. Over a period of time, such as weeks or months of operation, the deposit will cause a film to accumulate on the transparent panel. Increasing amounts of light will be reflected back to a light detector for detection.

[0081] Figure 2 is an image produced by energy dispersive X-ray spectroscopy of a layered deposition on a silicon test wafer placed on a graphite liner in an ion implantation system, and then the test wafer removed and inspected for deposition. As can be seen in Figure 2, different layers exhibit different types of deposition.

[0082] Energy dispersive X-ray spectroscopy (EDX) allows for the detection of different chemical species in the deposit. Figure 2 shows how deposits that differ in molecular composition can be distinguished by the brightness of the layers in the SEM image. For example, chamber liners are often made of graphite, and Faraday devices often contain graphite. This will produce a carbon-rich spectrum. Ion sources and dopants may produce fluorine, boron, arsenic, phosphorus, and germanium deposits. Using different wavelengths reflected from the deposited film provides a spectrum of the reflected light, which provides more information about which species are present in the deposit.

[0083] Depending on the shielding and the amount of light coming from within the system itself, there may be high levels of background light entering the detector. One way to calibrate the system for this is to pulse the light source and record a baseline signal for when the light source is off, and a separate average for when the light source is pulsed on. These averages can be taken over a period of time, such as one hour to one month, or one day to four weeks. In this way, a calibration for a baseline condition can be established. By subtracting the average detected light when the light source is off from the average detected light when the light source is on, a precisely calibrated signal can be determined for light reflected from the light source alone.

[0084] At operation 640, a processor is used to analyze the detected light reflected from the deposit. If the light has a different wavelength, this provides the operator with more information about the source of the deposit. Machine learning can be used to enable the processor to identify certain spectra as indicative of a failure or contamination in a specific area of the ion implant system. For example, a record of spectral data can be saved and correlated with background and known fault points. The collected spectral data can then be analyzed in real time by comparing it with previously stored and compiled data using machine learning. The results of the analysis can be provided for display to the operator.

[0085] Knowing the deposited composition allows maintenance to be focused on a specific area of the ion implantation system, reducing costs and system downtime. When maintenance actions are performed on the system, the actions taken and / or empirically determined conditions (e.g., deposited film depth and composition) can be input and stored as further training examples for machine learning.

[0086] At operation 650, a warning signal is sent to perform maintenance. This can be sent by the processor to a display, such as a monitor screen. The warning can indicate that maintenance is required within, for example, six months, three months, one month, or immediately. The warning can also indicate that a large change in reflectivity has occurred within a short period of time, thereby indicating a serious problem. Furthermore, a more detailed report can be provided regarding the raw data of the reflected spectral wavelengths, or processed data, aided by machine learning, indicating the composition of the deposited film.

[0087] Figure 7 illustrates a data set that can be used to trigger a warning. The example data set depicted in Figure 7 can be part of a report provided to an operator. For example, a single point for each wavelength can represent the deposition status at a given point in time. In another example, the history of deposited film accumulation can be displayed using multiple points for each wavelength. This data can also be used to predict when maintenance will be necessary by fitting a curve to the data and inferring the time until a maintenance threshold is reached. Examples

[0088] Figure 8 shows a top view of a sensor device 800, constructed to test the concepts disclosed above. The sensor device 800 includes a photodiode 840 in the center of a lamp 802. Five LEDs 891-895 emitting at different wavelengths are arranged around the photodiode 840. A first LED 891 emits light at 470 nm (blue light). A second LED 892 emits light at 525 nm (green light). A third LED 893 emits light at 630 nm (red light). A fourth LED 894 emits light at 850 nm (infrared light). A fifth LED 895 emits light at 780 nm (infrared light). A transparent panel is placed above the LEDs 891-895 and the photodiode 840 to reflect the light back toward the photodiode 840. To maximize the response from the photodiode 840, each LED 891-895 is oriented at an angle toward the center of the transparent panel to try to approximate the optimal angle for the photodiode to receive the reflected light.

[0089] The sensor device 800 was operated and tested using test panels with a DLC (diamond-like coating) film to simulate deposited film thicknesses of 500 nm, 750 nm, and 1000 nm. Changes in response at different wavelengths were observed using the different test panels. Example 1

[0090] Figure 9A shows a graph of data collected by measuring the entire visible and infrared range reflected onto a photodetector, separating the intensity at each wavelength. The results show differences in reflectance and response at different wavelengths for the same thickness. The rectangles on the graph in Figure 9A indicate the five wavelengths tested using the apparatus of Figure 8. This demonstrates that a simpler, less expensive apparatus using only five different wavelengths still provides a wealth of information about the deposited layer, enabling the user to determine thickness and possible composition differences. Example 2

[0091] FIG9B is a diagram showing a control example where five different LED wavelengths of the sensor device of FIG8 are reflected from an uncoated quartz transparent panel and measured. This helps to calibrate and normalize the sensor. Example 3

[0092] Figures 9C and 9D show test data from the sensor device of Figure 8 . Five different LED wavelengths from the sensor device of Figure 8 were reflected and measured from three coated test panels of varying thicknesses, positioned behind a transparent quartz panel. The results indicate that the reflectance coefficients of these five wavelengths can be used to distinguish coating thicknesses. For the same wavelength, different thicknesses produce different reflectance coefficients. For the same thickness, different wavelengths produce different reflectance coefficients. Example 4

[0093] Example 3 was repeated several times at different locations on two coated sample panels, and the results were very consistent, demonstrating the high precision of the sensor device. Figures 10A (500 nm thickness) and 10B (1000 nm thickness) show the repeatability of the sensor's performance at different locations on the sample panels.

[0094] The coating thickness was determined to be nearly identical (less than 1% variation) at all test locations across the coated quartz sample area. The signal-to-noise ratio response varied by only 1 mV. This statistically consistent data indicates that this approach will be successful in practical implementations of ion implantation systems.

[0095] Although the present disclosure has been shown and described with respect to certain applications and implementations, it will be appreciated that equivalent changes and modifications will occur to others skilled in the art upon reading and understanding this specification and the accompanying drawings. With respect to the various functions performed by the aforementioned components (assemblies, devices, circuits, systems, etc.), unless otherwise indicated, the terms used to describe such components (including any reference to "means") are intended to correspond to any component that performs the specified function of the component (i.e., is functionally equivalent), even if the structure is not identical to the disclosed structure, but performs the function described in the exemplary embodiments of the present disclosure described herein.

[0096] In addition, although a particular feature of the present disclosure may have been disclosed with respect to only one of several embodiments, such feature may be combined with one or more other features of other embodiments as may be desired and advantageous for any given or particular application. Furthermore, where the terms "including," "having," and variations thereof are used in the detailed description or claims, these terms are intended to be inclusive in a manner similar to the term "comprising."

[0097] 100:Ion implantation system 102: Terminal 104: Harness assembly 106: Terminal 108: ion source 110: Power supply 112: Ion Beam 114: Ion Generating Chamber 116: Slit 118: Ion extraction component 120a: Extraction / suppression electrode 120b: Extraction / suppression electrode 122: Artifact 124: Beam Guide 126:Mass Analyzer 128: Scanning system 130: Parallelizer and / or corrector component 132: Sidewall 134: Parsing hole 136: Mass Resolving Aperture Components 138: Magnetic scanning element 140: Focusing and control components 142: Power supply 144:Power supply 146a: Electromagnet 146b: Electromagnet 148a: Electrode 148b: Electrode 150: Scan Vertex 152: Scanned ion beam 154a: Bipolar magnet 154b: Bipolar magnet 156: reduction stage 158a: Electrode 158b: Electrode 160: Beam path 162: Dosimetry System 164:Analyzer 166:Analyzer path 168: Control System 175: Workpiece support 300: Sensor device 305: Side wall Room 310 315: Opening 320: Transparent panel 325: Seal 330: Inner wall 335: Photodetector 340: Light Source 345: Back panel 350: Processor 360: outer surface 365: Outer surface 370:Deposition film 375:Inner surface 380: Light 385:Reflected Light 500:Sensor device 510: Loading lock chamber 520: Transparent Panel Floor 535: Photodetector 540: Light Source 560: Processor 610: Operation 620: Operation 630: Operation 640: Operation 650: Operation 800:Sensor device 802: Lighting 840: Photodiode 891: First LED 892: Second LED 893: Third LED 894: Fourth LED 895: Fifth LED X: direction Y: direction

Claims

1. An ion implantation system, comprising: An ion source that generates ions and produces an ion beam along a beamline; a mass analyzer positioned downstream of the ion source that generates a magnetic field based on a selected charge-to-mass ratio and angle adjustment; a workpiece target associated with the beamline; and a controller configured to move the ion beam in relation to the workpiece target. And a sensing device coupled to the chamber of the ion implantation system, the sensing device including a photodetector, a light source, and a transparent panel; The transparent panel includes an outer surface and an inner surface, the outer surface facing the chamber and the inner surface facing away from the chamber, and the inner surface of the transparent panel is sealed against the outer surface of the transparent panel; wherein the photodetector is configured to receive light reflected from a deposition on the outer surface of the transparent panel.

2. The ion implantation system of claim 1, wherein the light source emits light of multiple wavelengths.

3. The ion implantation system of claim 1, further comprising a processor that causes the light source to emit pulsed light.

4. The ion implantation system of claim 1, further comprising a processor that receives an input signal from the photodetector, processes the input signal into a simplified signal, and sends the simplified signal to a main processor for the ion implantation system.

5. The ion implantation system of claim 1, further comprising a display screen configured to send a warning about a maintenance event based on a signal from the photodetector.

6. The ion implantation system of claim 1, wherein the light source includes an LED configured to emit light at wavelengths corresponding to red, green and blue light.

7. The ion implantation system of claim 1, wherein the light source includes an LED configured to emit light at an infrared wavelength.

8. The ion implantation system of claim 1, wherein the chamber is selected from the loading lock chamber, the dosimetry system chamber, the ion source chamber, and the mass analyzer chamber.

9. The ion implantation system of claim 1, wherein the chamber is configured to be under vacuum during operation.

10. A deposition sensor device for a semiconductor manufacturing system, the sensor device comprising: Photodetector, light source, and transparent panel; The transparent panel includes an outer surface and an inner surface, the inner surface of the transparent panel being sealed against the outer surface of the transparent panel, wherein the light source is configured to emit light toward the inner surface of the transparent panel, and the photodetector is configured to receive light reflected from a deposition on the outer surface of the transparent panel.

11. The deposition sensor device of claim 10, wherein the photodetector and the light source are coupled to a backplane.

12. The deposition sensor device of claim 10, wherein the light source includes an LED configured to emit light at wavelengths corresponding to red, green and blue light.

13. The deposition sensor device of claim 10, wherein the light source includes an LED configured to emit light at an infrared wavelength.

14. The deposition sensor device of claim 10, further comprising a processor that receives an input signal from the photodetector, processes the input signal into a simplified signal, and sends the simplified signal to a main processor for the ion implantation system.

15. A method for detecting deposition in a semiconductor manufacturing apparatus, comprising: To perform ion implantation, etching, or deposition operations; The system emits light toward the inner surface of a transparent panel having an inner surface and an outer surface, the inner surface of which is sealed against the outer surface of the transparent panel; detects light reflected from a deposition on the outer surface of the transparent panel, the deposition being generated during an ion implantation operation; processes the detected light reflected from the deposition; and sends a warning signal for performing maintenance.

16. The method of claim 15, wherein the light includes wavelengths corresponding to red, green and blue light.

17. The method of claim 15, wherein the light includes a wavelength corresponding to infrared light.

18. The method of claim 15, wherein the processing includes comparing the detected light with previously collected light detection data compiled through machine learning to determine that the maintenance of the ion implantation system is due.

19. The method of claim 15, wherein, in operation, a vacuum is applied to a chamber adjacent to the outer surface of the transparent panel.

20. The method of claim 15, wherein the emitted light is from a multi-color LED array, and the detected light is detected by a photodiode, and the multi-color LED array and the photodiode are adjacent to each other and oriented in the same direction.

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