Displacement measurements in semiconductor wafer processing

Abstract

Wafers, which start as flat surfaces during the semiconductor manufacturing process, may warp or bend as layers and features are added to the underlying substrate. This warping can be detected between manufacturing processes by rotating the wafer adjacent to a displacement sensor. The displacement sensor can generate displacement data relative to baseline measurements to identify areas of the wafer that are warped upward or downward. The displacement data can then be mapped to locations on the wafer corresponding to alignment features. This mapping can then be used to adjust parameters in subsequent semiconductor processes, including adjusting how the carrier head holds the wafer or applies pressure to the wafer during the polishing process when the wafer is polished.

Description

Technology Field

[0001] This application claims the benefit and priority thereto of U.S. Official Application No. 17 / 334,407, filed on May 28, 2021, titled "DISPLACEMENT MEASUREMENTS IN SEMICONDUCTOR WAFER PROCESSING," the contents of which are incorporated herein by reference in their entirety for all purposes.

[0002] The present disclosure generally relates to measuring wafer warping between semiconductor manufacturing processes. Specifically, the present disclosure describes measuring displacement data around a wafer to characterize the wafer warping / bending, and then using the displacement data to control subsequent processes to compensate for the warping / bending. Background Technology

[0003] Integrated circuits are typically formed on a substrate by the sequential deposition of conductive, semiconducting, and / or insulating layers on a silicon wafer. Various manufacturing processes utilize planarization of layers on the substrate between processing steps. For example, in the case of polishing a metal layer to form vias, plugs, and / or lines within trenches of a patterned layer, the overlying layer is planarized until the top surface of the patterned layer is exposed. In other applications, such as the planarization of a dielectric layer for photolithography, the overlying layer is polished until a desired thickness remains on the underlying layer.

[0004] Chemical mechanical polishing (CMP) is a common method of planarization. This planarization method typically requires that a substrate be mounted on a carrier or a polishing head. The exposed surface of the substrate is typically positioned toward a rotating polishing pad. The carrier head provides a controllable load on the substrate to push it toward the polishing pad. An abrasive polishing slurry is typically supplied to the surface of the polishing pad.

[0005] One challenge in CMP and other semiconductor processes is maintaining a consistent surface on the wafer. Although a wafer may start as a relatively flat silicon crystal, various semiconductor processes can place layers or features on the wafer by depositing, growing, adding, etching, removing, and / or otherwise. These additional layers and features can accumulate, causing stresses to build up on the wafer. These stresses can then cause the wafer to bend or warp. This warping can lead to problems where the wafer surface is no longer uniform when polishing or cleaning.

[0006] In some embodiments, the system may include a platform configured to support the wafer and rotate the wafer around the center of the wafer; and one or more displacement sensors positioned to measure the displacement of the wafer when the wafer is rotated.

[0007] In some embodiments, a method for measuring the displacement of wafers between semiconductor manufacturing processes may include rotating the wafer around the center of the wafer; generating displacement data by measuring the displacement of the wafer at a predetermined distance from the center of the wafer when the wafer is rotated; and controlling a polishing process or a cleaning process performed on the wafer using the displacement data.

[0008] In some embodiments, a non-transient computer-readable medium may include instructions that, when executed by one or more processors, cause one or more processors to perform operations including receiving displacement data generated using a displacement sensor with respect to a wafer—the displacement data may indicate a curved or bent area on the wafer—; identifying parameters of a carrier head corresponding to a location of a curved or bent area on the wafer—the carrier head may be part of a chemical-mechanical polishing (CMP) machine or a wafer cleaning machine—and adjusting the parameters of the carrier head to compensate for a curved or bent area on the wafer during a cleaning or polishing process.

[0009] In any embodiment, any and all of the following features may be implemented in any combination and without limitation. The system may also include an alignment sensor positioned to detect a notch in the wafer when the wafer is rotated. One or more displacement sensors may include a laser displacement sensor; and the alignment sensor may include a through-beam sensor. One or more displacement sensors may also be positioned to detect a notch in the wafer when the wafer is rotated. One or more displacement sensors may include a displacement sensor positioned above the wafer. One or more displacement sensors may include a displacement sensor positioned below the wafer. One or more displacement sensors may include a plurality of displacement sensors positioned along the radial line of the wafer. One or more displacement sensors may include a plurality of displacement sensors positioned at different rotation angles around the wafer. Methods / operations may also include measuring the displacement of a baseline wafer to generate baseline displacement data representing a flat wafer surface. Generating displacement data may include determining the displacement of the wafer relative to baseline displacement data. Methods / operations may also include mapping the displacement data to two-dimensional coordinates on the wafer based on alignment data. Methods / operations may also include mapping the displacement data to angles of rotation on the wafer based on alignment data. Methods / operations may also include identifying a displacement region on the wafer from the displacement data and providing the displacement region to a polishing process or a cleaning process. Adjusting the parameters of the carrier head may include adjusting the angle at which the carrier head grips the wafer during the cleaning or polishing process.Adjusting the parameters of the carrier head may include adjusting the amount of pressure provided for a curved or warped area on the wafer during a cleaning or polishing process. Adjusting the amount of pressure may include identifying a chamber within the carrier head adjacent to the curved or warped area on the wafer; and adjusting the pressure within the chamber to compensate for the curved or warped area on the wafer. Adjusting the amount of pressure may include adjusting the pressure at which a brush cleans the curved or warped area on the wafer during a cleaning process. Displacement data may be generated using a displacement sensor by rotating the displacement sensor around the wafer. Brief explanation of the drawing

[0010] Further understanding of the nature and benefits of the various embodiments may be realized by reference to the drawings and the remainder of this specification, wherein similar reference numbers are used throughout the drawings to refer to similar components. In some cases, a sub-label is associated with a reference number to indicate one of a number of similar components. Where a reference to a reference number is made without specifying an existing sub-label, it is intended to refer to all such a number of similar components.

[0011] FIG. 1 illustrates a schematic cross-sectional view of an example of a polishing device according to some embodiments.

[0012] FIG. 2 illustrates a measured spectrum from an in-situ optical monitoring system according to some embodiments.

[0013] FIG. 3 illustrates the path of a sequence of spectrum measurements on a substrate according to some embodiments.

[0014] FIG. 4 illustrates a system for measuring wafer displacement according to some embodiments.

[0015] FIG. 5a illustrates a displacement sensor positioned at the edge of a wafer according to some embodiments.

[0016] FIG. 5b illustrates a displacement sensor positioned to measure the displacement of the bottom edge of a wafer according to some embodiments.

[0017] FIG. 5c illustrates a plurality of displacement sensors according to some embodiments.

[0018] FIG. 5d illustrates a plurality of displacement sensors positioned at different rotational angles according to some embodiments.

[0019] FIG. 6 illustrates a three-dimensional graph of displacement data according to some embodiments.

[0020] FIG. 7a illustrates a baseline wafer that can be measured by a displacement sensor according to some embodiments.

[0021] FIG. 7b illustrates a convex wafer according to some embodiments.

[0022] FIG. 7c illustrates a concave wafer according to some embodiments.

[0023] FIG. 8 illustrates a graph of displacement data for bent wafers according to some embodiments.

[0024] FIG. 9 illustrates a flowchart of different processes that can be executed as part of a semiconductor manufacturing process according to some embodiments.

[0025] FIG. 10 illustrates a flowchart of a method for measuring the displacement of wafers during semiconductor manufacturing processes according to some embodiments.

[0026] FIG. 11 illustrates an exemplary computer system in which various embodiments can be implemented. Specific details for implementing the invention

[0027] FIG. 1 illustrates an example of a polishing device (100). The polishing device (100) may include a rotatable disc-shaped platen (120) on which a polishing pad (110) can be positioned. The platen may be operable to rotate around an axis (125). For example, a motor (121) may rotate the platen (120) by rotating a drive shaft (124). The polishing pad (110) may be a two-layer polishing pad having an outer polishing layer (112) and a softer backing layer (114).

[0028] The polishing device (100) may include a port (130) for dispensing a polishing liquid (132), such as a slurry, onto a polishing pad (110). The polishing device may also include a polishing pad conditioner for wearing down the polishing pad (110) to maintain the polishing pad (110) in a consistent polishing state.

[0029] The polishing device (100) may include at least one carrier head (140). The carrier head (140) may be operable to hold the substrate (10) against the polishing pad (110). The carrier head (140) may have independent control of polishing parameters associated with each individual substrate, for example, pressure.

[0030] In particular, the carrier head (140) may include a retaining ring (142) for holding the substrate (10) under the flexible membrane (144). The carrier head (140) may also include a plurality of independently controllable pressurizable chambers defined by the membrane, for example, three chambers (146a-146c), which can apply independently controllable pressures to associated zones on the flexible membrane (144) and thus on the substrate (10). For ease of illustration, only three chambers are illustrated in FIG. 1, but in other embodiments, there may be one or two chambers, or four or more chambers, for example, five chambers.

[0031] The carrier head (140) may be suspended from a support structure (150), for example, a carousel or a track, and may be connected to a carrier head rotation motor (154) by a drive shaft (152) so that the carrier head can rotate about an axis (155). Optionally, the carrier head (140) may move laterally, for example, on sliders on the carousel (150) or track; or by rotational vibration of the carousel itself. In operation, the platen may rotate about its center axis (125), and the carrier head may rotate about its center axis (155) and / or translate laterally across the top surface of the grinding pad.

[0032] Although only one carrier head (140) is shown, more carrier heads may be provided to hold additional substrates so that the surface area of ​​the polishing pad (110) can be used efficiently. The polishing device may also include an in-situ monitoring system (160). The in-situ monitoring system may generate a sequence of values ​​that vary over time, depending on the thickness of the layer on the substrate. The in-situ monitoring system (160) may include an optical monitoring system. In particular, the in-situ monitoring system (160) may measure a sequence of spectra of light reflected from the substrate during polishing.

[0033] Optical access (108) through the polishing pad may be provided by including an aperture (i.e., a hole extending through the pad) or a solid window (118). The solid window (118) may be secured to the polishing pad (110), for example, as a plug that fills the aperture of the polishing pad. Alternatively, the solid window may be molded into the polishing pad or secured using adhesive, but in some embodiments, the solid window may be supported on a platen (120) and protrude into the aperture of the polishing pad.

[0034] The optical monitoring system (160) may include a light source (162), a light detector (164), and a remote controller (190), for example, a circuitry (166) for transmitting and receiving signals between the light source (162) and the light detector (164). One or more optical fibers may be used to transmit light from the light source (162) to the optical access of the polishing pad and to transmit light reflected from the substrate (10) to the detector (164). For example, a bifurcated optical fiber (170) may be used to transmit light from the light source (162) to the substrate (10) and then to the detector (164). The bifurcated optical fiber may include a trunk (172) positioned close to the optical access, and two branches (174 and 176) connected to the light source (162) and the detector (164), respectively.

[0035] In some embodiments, the top surface of the platen may include a recess (128) into which an optical head (168) is fitted to hold one end of the trunk (172) of the branched optical fiber. The optical head (168) may include a mechanism for adjusting the vertical distance between the top of the trunk (172) and the solid window (118).

[0036] The output of the circuit section (166) may be a digital electronic signal transmitted to a controller (190) for an optical monitoring system via a rotary coupler (129) of the drive shaft (124), for example, a slip ring. Likewise, the light source may be turned on or turned off in response to control commands of digital electronic signals transmitted from the controller (190) to the optical monitoring system (160) via the rotary coupler (129). Alternatively, the circuit section (166) may communicate with the controller (190) via a wireless signal.

[0037] The light source (162) may be operated to emit ultraviolet (UV), visible light, or near-infrared (NIR) light. The photodetector (164) may be a spectrometer. A spectrometer is an optical instrument for measuring the intensity of light for a portion of the electromagnetic spectrum. For example, a grating spectrometer may be used. Typical outputs of a spectrometer may include the intensity of light as a function of wavelength (or frequency). FIG. 2 illustrates an example of a measured spectrum (200) having intensity as a function of wavelength.

[0038] As mentioned above, the light source (162) and the light detector (164) may be connected to an operable computing device, for example, a controller (190), to control their operation and receive their signals. The computing device may include a microprocessor located near the polishing device. For example, the computing device may be a programmable computer. In relation to control, the computing device may, for example, synchronize the activation of the light source with the rotation of the platen (120). A display (192), for example, an LED screen, and a user input device (194), for example, a keyboard and / or a mouse, may be connected to the controller (190).

[0039] In operation, the controller (190) may receive a signal that carries information describing the spectrum of light received by the photodetector during a specific flash of the light source or a time frame of the detector, for example. Thus, this spectrum may be the spectrum measured in situ during polishing. Although not limited to any particular theory, the spectrum of light reflected from the substrate (10) may gradually change as polishing proceeds due to changes in the thickness of the outermost layer, and thus may yield a sequence of spectra that change over time.

[0040] The optical monitoring system (160) may be configured to generate a sequence of spectra, or "spectral data," measured at a measurement frequency. Relative movement between the substrate (10) and the optical access (108) causes the spectra of the sequence to be measured at different positions on the substrate (10). In some embodiments, a light beam generated by the light source (162) may be emitted from a point (indicated by the arrow (R) in FIG. 3) that rotates together with the platen (120). As illustrated in FIG. 3, in such an embodiment, relative movement between the substrate (10) and the optical access (108) may cause the spectra to be measured at positions (300) of a path across the substrate (10). In some embodiments, only one spectrum is measured per rotation of the platen. Also, in some embodiments, the emission point of the light beam is fixed, and measurements are taken only when the optical access (108) is aligned with the light beam.

[0041] The CMP process represents one of many different processes that can be performed during the manufacturing of semiconductor wafers. When different layers and features are added to a substrate, the CMP process can be used to flatten the wafer and remove specific amounts of material between stages. Ideally, a wafer can start as a completely flat silicon crystal substrate. However, as layers and features are added to the substrate, this additional material adds stress to the structure and can cause warping or curvature in the wafer. Such warping can cause problems during the CMP process because the wafer is polished unevenly, which can result in layers with non-uniform thickness after the CMP process is completed.

[0042] The embodiments described herein address these and other technical problems by characterizing the vertical displacement of a wafer between semiconductor manufacturing processes. Displacement measurements can be taken around the perimeter of the wafer using a displacement sensor. The resulting displacement data can then be used to control the polishing process, the cleaning process, and / or the angle or orientation at which the wafer is handled. This allows subsequent semiconductor processes to compensate for wafer warping.

[0043] FIG. 4 illustrates a system (400) for measuring wafer displacement according to some embodiments. The system (400) may include a platform (412) configured to support a wafer (404) and to rotate the wafer (404) around a central axis (414) of the wafer (404). For example, before being placed in a CMP machine, an operator or a robotic arm may place the wafer (404) on the platform (412). Then, the platform (412) may rotate the wafer (404) around the central axis (414). Various sensors may measure properties of the wafer (404) during rotation.

[0044] In some embodiments, the system (400) may include an alignment sensor. The alignment sensor may be implemented using a through-beam sensor configured to pass a beam of light between the first component (401) and the second component (403). The alignment sensor may be configured to detect when the beam is blocked between the first component (401) and the second component (403). Thus, the alignment sensor may be used in conjunction with the rotation of the wafer (404) provided by the platform (412) to align the wafer (404) to a predefined orientation. For example, the wafer (404) may include a notch (416) or other edge feature along the outer perimeter of the wafer (404). Generally, when the wafer (404) rotates about the central axis (414), the wafer (404) will block the beam between the first component (401) and the second component (403). However, if the notch (416) location along the edge of the wafer (404) passes over the first component (401) of the alignment sensor, the beam can be detected by the second component (403) and thus the location of the notch (416) can be indicated.

[0045] Once the location of the notch (416) is identified on the wafer (404), the system (400) may optionally rotate the wafer (404) to a predetermined orientation. For example, in some cases, the system (400) may stop the rotation of the wafer (404) when the notch (416) is located. In other cases, the system (400) may continue to rotate the wafer (404) until a predetermined angle of rotation is reached. This process performed by the system (400) may be used to ensure that the wafer (404) is rotated to a known orientation before being moved to a subsequent machine in the semiconductor manufacturing process. For example, some systems may use robotic arms to handle the wafer (404) as it is moved between various machines. Before being placed on the polishing pad of a CMP machine (or any other semiconductor manufacturing machine), the wafer (404) may be rotated to a known position. As described below, this alignment and rotational orientation of the wafer (404) can also be used to identify curved or bent locations on the wafer (404).

[0046] The system (400) may be implemented at least partially by a machine referred to as an aligner. Specifically, the aligner may be configured to rotate the wafer (404) until the notch (416) is located. In some embodiments, the aligner may be modified to also perform distance or displacement measurements on the wafer (404) when the wafer (404) is rotated. The system (400) may further include a displacement sensor (406). As used herein, the term "displacement sensor" may include any sensor configured to measure the distance from the sensor to a surface. In some embodiments, as an example, a laser displacement sensor may be used. The laser displacement sensor may emit one or more laser beams aimed at the surface of the wafer (404) and receive reflections from the wafer (404). Then, the displacement sensor (406) may calculate the distance between the displacement sensor (406) and the surface of the wafer (404) to which the laser beam is aimed. When the wafer (404) is rotated around the central axis (414), the displacement sensor (406) can continuously sample distance measurements for the surface of the wafer (404).

[0047] When modifying the aligner, the system (400) may also include a computer system that controls and / or records displacement data received from the displacement sensor (406). The computer system may include one or more processors (e.g., microprocessors, microcontrollers, digital controllers, FPGAs, programmable hardware, etc.) configured to control the operation of the displacement sensor (406) and to record the displacement data. One or more processors may be an integrated part of the system (400). Alternatively, one or more processors may be part of a separate computer system that communicates with the displacement sensor (406) via a wired or wireless interface. Instructions for controlling the displacement sensor (406) may be stored on one or more memory devices, such as a non-transient computer-readable medium, and these instructions may enable one or more processors to perform operations such as receiving and processing displacement data, rotating the wafer (404), repackaging the displacement data, etc. An example of a computer system is described in Fig. 11 below.

[0048] A displacement sensor may be positioned to measure the displacement of the wafer (404) when the wafer (404) is rotated. Measuring the displacement of the wafer (404) may generate displacement data. The displacement data may include a distance measurement from the displacement sensor (406) to the wafer (404). Alternatively, the displacement data may include the displacement of the wafer (404) from a baseline location. For example, the baseline location for the wafer (404) may be determined by measuring displacement data for a bare silicon substrate or another wafer known to be flat as a reference. If the wafer (404) is bent downward such that the displacement measurement is longer than the baseline displacement, the displacement data may include negative values. If the wafer (404) is bent upward such that the displacement measurement is shorter than the baseline displacement, the displacement data may include corresponding positive values.

[0049] The example of FIG. 4 includes a system (400) that combines an aligner and a displacement sensor (406). However, instead of modifying the aligner to include the displacement sensor (406), other systems may omit the aligner and provide a dedicated displacement sensor equipped with a platform that rotates the wafer (400). In other embodiments, the displacement sensor (406) itself may rotate around a central axis (414) while the wafer (404) is kept stationary. In these embodiments, the displacement sensor itself may replace the aligner and perform alignment functions together with the displacement sensor (406). For example, the displacement sensor (406) may collect displacement data and detect the location of the notch (416).

[0050] FIG. 5a illustrates a displacement sensor (506a) positioned at the edge of a wafer (504) according to some embodiments. In the example of FIG. 4 above, the displacement sensor (506) may be aimed at the outer edge of the wafer. For example, the outer edge of the wafer may include the outermost 1 cm of the wafer (504) so ​​that the displacement measurement characterizes the displacement along the outer edge of the wafer (504). This positioning of the displacement sensor (506a) may provide specific technical advantages. Specifically, the curvature or bending of the wafer (504) may be most pronounced at the edge. Since the wafer (504) is mounted on a platform in the central portions of the wafer (504), the greatest displacement may be measured along the edge of the wafer (504). Additionally, when aimed at the edge of the wafer, the displacement sensor (506a) may also perform the function of an aligner. Specifically, the displacement sensor (506a) can continuously sample displacement measurements from the wafer (504). When a notch is encountered in the wafer (504), the displacement measurement may exceed a negative threshold distance, and the displacement sensor (506a) can interpret this measurement as the location of the notch. Thus, the displacement sensor (506a) can determine orientation and displacement data for the wafer (504).

[0051] FIG. 5b illustrates a displacement sensor (506b) positioned to measure the displacement of the bottom edge of a wafer (504) according to some embodiments. Instead of being positioned above the wafer (504) as illustrated in FIG. 5a, the displacement sensor (506b) may be placed below the wafer (504). This positioning of the displacement sensor (506b) may provide specific technical advantages. Specifically, when a robotic arm is used to move the wafer (504) to / from the system, the displacement sensor (506b) positioned below the wafer (504) will typically not interfere with the movement of the wafer (504) by the robotic arm when the robotic arm lifts the wafer (504). Another technical advantage provided by this arrangement involves the effect of the emission displacement sensors on semiconductor devices. Typically, devices on the wafer may be placed on the top side of the wafer (504) and exposed. By placing the displacement sensor (506b) under the wafer (504), the system can prevent lasers or other high-intensity light sources from shining onto these semiconductor devices. This can be advantageous if these semiconductor devices are particularly sensitive to high-intensity light.

[0052] FIG. 5c illustrates a plurality of displacement sensors (506c, 508c) according to some embodiments. In this example, the plurality of displacement sensors (506c, 508c) may be positioned on a radial line (510) extending outward from the center of the wafer (504). This allows the system to measure displacement data at multiple points of each rotation angle. Although the example in FIG. 5c illustrates two displacement sensors (506c, 508c), this number of displacement sensors is provided merely as an example and is not intended to be limited. Other embodiments may include more than two displacement sensors. When the plurality of displacement sensors measure displacement data along the radial line (510), the system can generate a displacement map of multiple locations on the wafer (504) to generate a displacement map of the entire surface of the wafer (504), rather than just the edges of the wafer. Prior to the present disclosure, a measurement station was required to perform a laser scan of the entire surface of the wafer (504) to generate an accurate view of many different aspects of the wafer (504). However, the measurement station is expensive and time-consuming to operate. Providing a plurality of displacement sensors (506c, 508), as depicted in FIG. 5c, can provide surface mapping of displacement data for the wafer (504) by replacing at least some of the operations performed by the measurement station with a low-cost, high-speed process.

[0053] FIG. 5d illustrates a plurality of displacement sensors (506d, 508d) positioned at different rotational angles according to some embodiments. Instead of positioning the displacement sensors (506d, 508d) along the same radial line at different radial distances, some embodiments may position the displacement sensors (506d, 508d) at the same radial distance separated by a known rotational angle (512). These embodiments may provide redundant displacement data for a location as a backup in the event that one of the displacement sensors (506d, 508d) fails. These embodiments may also use the redundant displacement data to characterize, calibrate, and / or detect malfunctions in the displacement sensors (506d, 508d). Note that more than two displacement sensors may also be used without limitation. Another technical advantage provided by aligning multiple displacement sensors (506d, 508d) at the same radial distance is the collection of parallel data for the wafer (504). For example, by placing multiple displacement sensors (506d, 508d) on the wafer (504) at approximately 180° apart, the entire wafer perimeter can be measured in half a rotation rather than a full rotation. Similarly, by placing four displacement sensors on the wafer (504) at approximately 90° apart, the entire wafer perimeter can be measured in 1 / 4 a rotation rather than a full rotation. Thus, these configurations can reduce the total time required to collect displacement data by 50%, 25%, etc.

[0054] The combinations of different displacement sensor numbers and / or locations exemplified in FIGS. 5a and 5b may be used in any combination and without limitation. For example, some embodiments may include a plurality of displacement sensors located at different rotational angles and / or different radial distances on the top side of the wafer, and, optionally, additional displacement sensors located at different rotational angles and / or different radial distances on the bottom side of the wafer. Some embodiments may also use different sensor types or configurations when multiple displacement sensors are used. For example, some embodiments may use a plurality of laser displacement sensors, each operating at a different optical frequency. Different frequencies may be reflected differently from the wafer, and thus using different optical frequencies for different sensors can improve the accuracy of the overall displacement data measurement. Additionally, some embodiments may use different sensor types when multiple displacement sensors are used. For example, a laser displacement sensor may be used at one location and an ultrasonic displacement sensor may be used at another location.

[0055] FIG. 6 illustrates a three-dimensional (3D) graph (600) of displacement data according to some embodiments. The graph (600) includes distance measurements for the default or baseline displacement of the wafer. Locations on the wafer may be mapped to Cartesian coordinates on a millimeter scale. These coordinates may be assigned based on alignment data for the notch. For example, the notch location may be assigned the coordinate position (0, 150) in the (x, y) plane of the graph (600). Thus, once the alignment position of the displacement data is captured, some embodiments may rotate the displacement data to match the coordinate locations based on the notch location.

[0056] In this example, displacement data is stored as a vertical distance relative to the baseline location. For example, the ring (602) may represent the baseline location of the wafer where no curvature or bending exists. Data points (604) representing distances measured above the baseline location may be expressed as positive displacements. These data points (604) may correspond to locations on the wafer that are curved or bent upward relative to the center of the wafer. Data points (606) representing distances measured below the baseline location may be expressed as negative displacements. These data points (606) may correspond to locations on the wafer that are curved or bent downward relative to the center of the wafer.

[0057] Displacement data can be stored for each wafer as each wafer is rotated on the platform. Additionally, displacement data for each displacement sensor of the wafer measuring system can be stored. For a single wafer, displacement data from various displacement sensors can be combined to generate a 3D mapping of displacements across the entire surface of the wafer. This displacement data can then be transmitted to other machines in the semiconductor processing pipeline and used to control operations for those machines as described below.

[0058] FIG. 7a illustrates a baseline wafer (704) that can be measured by a displacement sensor (706) according to some embodiments. The baseline wafer (704) may be an ideally flat wafer in the z-plane. In other words, the baseline wafer (704) may generate displacement data representing a constant baseline displacement (720) aligned with the surface of the wafer (704). The displacement data received from the baseline wafer (704) may be used to characterize the relative displacement of other subsequent wafers measured by the system. The baseline wafer (704) may be measured as part of a calibration or initialization process for the system. Displacement data from subsequent measurements of subsequent wafers may be subtracted from the displacement data from the baseline wafer. Although not explicitly shown in FIG. 7a, embodiments including a plurality of displacement sensors may store baseline displacement data for each sensor. Displacement data measured from subsequent wafers may be subtracted from the baseline displacement data for each corresponding displacement sensor.

[0059] FIG. 7b illustrates a convex wafer (704b) according to some embodiments. The convex profile indicates that the wafer (704b) is curved or bent downward at the edges of the wafer (704b) relative to the center of the wafer. The displacement (722) may be greater than the baseline displacement (720) and may result in negative values ​​for the displacement (722) when subtracted from the baseline displacement (720). Likewise, FIG. 7c illustrates a concave wafer (704c) according to some embodiments. The concave profile indicates that the wafer (704c) is curved or bent upward at the edges of the wafer (704c) relative to the center of the wafer. The displacement (724) may be smaller than the baseline displacement (720) and may result in positive values ​​for the displacement (724) when subtracted from the baseline displacement (720).

[0060] FIG. 8 illustrates a graph (800) of displacement data for curved wafers according to some embodiments. Instead of being mapped to 2D coordinates on 3D axes, the displacement data may be mapped to 2D axes, where the x-axis indicates the angle of rotation and the y-axis indicates the displacement relative to the baseline. The mapping for the angle of rotation may also be based on alignment data to determine the origin for the rotation. The displacement data (802) corresponds to a wafer that may include concave and / or convex portions. This type of wafer may be characterized as a "potato chip" shape that wavy up and down along the wafer edge. The displacement data (804) corresponds to a wafer having one side that is twisted or curved upward. The graph (800) illustrates how displacement data for any type of curved or bent state of a wafer may be characterized by the system described herein.

[0061] Mapping of the 2D coordinates in Fig. 6, or mapping of the angles of rotation in Fig. 8, can be used to control subsequent processes. For example, the 2D coordinates in Fig. 6 can be used to identify 2D regions of a wafer that need to be polished more, cleaned more, or exposed to differential pressures during the polishing process. For example, these differential pressures may include lower pressures in some regions and higher pressures in others to compensate for irregularities in the wafer, such as those indicated in the displacement data. Adjacent regions of displacement on the wafer can be grouped together into a single region and mapped to a specific pressurized chamber of the CMP carrier head. These regions on the wafer can be identified in the mapped data described above.

[0062] FIG. 9 illustrates a flowchart (900) of different processes that may be executed as part of a semiconductor manufacturing process according to some embodiments. Note that prior to the start of the flowchart (900), the wafer may have been processed using various semiconductor machines, such as machines that perform various deposition processes, etching processes, etc. After these processes are executed, a robotic arm may move the wafer onto a wafer aligner / displacement measuring system (902). This system (902) may be implemented using the system (400) described above. The wafer aligner / displacement measuring system (902) may generate displacement data (908).

[0063] A robotic arm can move a wafer onto a CMP machine (904) to perform a CMP process. Displacement data (908) can be transmitted to a handling control unit (910) and / or an endpoint control unit (912) for the CMP machine (904). Then, the displacement data can be used to control a polishing process performed on the wafer. Specifically, the CMP machine (904) may include a carrier head that grips or holds the wafer. The carrier head may be associated with a number of parameters. These parameters can control the angle at which the wafer is gripped by the carrier head, and / or the amount of pressure applied to the wafer at various locations. These parameters can be adjusted on the carrier head to compensate for curved or bent areas on the wafer during the cleaning or polishing processes described below.

[0064] For example, displacement data (908) can be used to control how the handling control unit (910) grips the wafer. For example, a flat wafer may be gripped by the carrier head using more force than a curved wafer. The CMP machine may receive displacement data and adjust the gripping force applied to the wafer based on the amount of displacement identified in the displacement data. Additionally, if the wafer is curved along a portion of the wafer's circumference, the handling control unit (910) may grip the wafer at a slight angle so that the curved portion protrudes slightly more than the rest of the wafer from the carrier head (140) of the CMP machine (100) illustrated in FIG. 1. Additionally, the chambers (146) may be pressurized based on the displacement data (908). Specific chambers (146) located behind the curved portions of the wafer may be pressurized more than other chambers to push the curved portions in alignment with the rest of the wafer or to apply greater pressure during the polishing process. This can create a flat surface on the wafer when the wafer is pushed against the polishing pad of the CMP machine (904). Since the orientation of the wafer is known from the alignment procedure, displacement data can be mapped to specific chambers (146) of the carrier head (140) located over the curved portions of the wafer. These chambers may be pressurized more or less based on positive / negative displacement data associated with each corresponding area of ​​the wafer.

[0065] The displacement data (908) may also be used by the endpoint control unit (912) of the CMP process performed by the CMP machine (904). For example, the real-time thickness of the top layer film on the wafer may be measured when the wafer is polished using the process described in FIGS. 1 through 3 above. For example, a flat wafer may be polished faster and with more force than a curved or bent wafer. Without access to the displacement data, the polishing process generally uses an average or worst-case polishing speed / pressure to accommodate both flat and bent wafers. However, if the wafer can be characterized as flat or bent using the displacement data, the speed / pressure applied during the polishing process may be adjusted accordingly. The CMP machine may use the displacement data to determine whether the wafer is flat, and if the wafer is flat, the CMP machine may increase the speed / pressure of the polishing process. If the wafer is not flat, the CMP machine may reduce the speed or pressure of the polishing process. This may lead to a 5% to 10% increase in the throughput of wafers through the polishing process. Displacement data may also be provided to the CMP machine (904) to allow both flat and curved wafers to be polished to have similar desired post-polishing characteristics. For example, the curved portion of the wafer may be polished more than the flat portion of the wafer to create a flat surface for the entire wafer. Some embodiments may also adjust other parameters of the polishing process based on the displacement data. For example, a substantially flat wafer may use a higher temperature or a slurry with higher abrasiveness to polish faster, while a curved wafer may use a slurry with lower abrasiveness to polish more finely, or vice versa.Additionally, while the wafer is being polished, temperatures and chemical additives may be applied to different areas on the wafer. For example, a first chemical additive and / or temperature for the slurry may be used on the curved part of the wafer, while a second chemical additive and / or temperature may be used on the flat part of the wafer.

[0066] Measurements of reflected wavelengths may be affected by wafer displacement from the polishing pad. Displacement data (908) may be used to compensate for locations on the wafer that may be curved or bent and thus lead to inaccurate thickness measurements of the surface being polished. For example, a positive displacement data indicating that the wafer is curved toward the polishing pad may subtract or add a proportional amount from the thickness measurement based on the effect of the displacement on the reflected wavelengths received by the spectrometer. Ultimately, the endpoint may be adjusted to polish the curved portions of the wafer more than other portions of the wafer to create a completely flat surface on the wafer for subsequent steps of the semiconductor manufacturing pipeline.

[0067] Next, the wafer may be moved to a cleaner (906) or wafer cleaning machine configured to clean the wafer from debris left after the polishing process. Displacement data (908) may be transmitted to the handling control unit (914) of the cleaner (906) and / or to software implementing the cleaning recipe (916). The cleaner (906) may include a carrier head similar to the carrier head described above for the CMP machine (904). Next, the displacement data (908) may also be used to control the cleaning process performed on the wafer. For example, the handling control unit (914) may be modified to grip the wafer differently based on the displacement data so that the wafer is more uniformly oriented for the cleaning process, as described above for the polishing process. Additionally, the cleaning recipe (916) may be modified based on the wafer's warp / curvature profile. Parts of the wafer corresponding to the curved areas may be cleaned more or less based on relative positive / negative values ​​in the displacement data. For example, the pressure applied by the brush to the wafer may be adjusted using positive / negative displacement data to apply more or less pressure to the protruding areas of the wafer in the cleaning machine.

[0068] FIG. 10 illustrates a flowchart (1000) of a method for measuring the displacement of wafers during semiconductor manufacturing processes according to some embodiments. The method may include rotating the wafer around the center of the wafer (1002). This rotation may be performed when the wafer is supported on a platform, as illustrated in FIG. 4 above. This rotation may also be used simultaneously to locate and align notches on the wafer using an alignment sensor.

[0069] The method may further include generating displacement data (1004) by measuring the displacement of the wafer at a predetermined distance from the center of the wafer when the wafer is rotated. The predetermined distance may correspond to a position where the displacement sensor reads the displacement data from the wafer. The predetermined distance may be located at any point along the outer edge of the wafer, along a radial line extending from the center of the wafer, and / or at an angular displacement from an alignment sensor or another displacement sensor as illustrated in FIGS. 5a through 5d above. The displacement data may characterize displacement measurements from a plurality of different displacement sensors. The displacement sensor may be implemented using a laser displacement sensor or any other type of displacement sensor configured to measure distances.

[0070] The method may additionally include using displacement data (1006) to control a polishing or cleaning process performed on a wafer. This part of the method may be optional, and some embodiments of the method may use displacement data to characterize the wafer without using displacement data to control any other processes. For example, displacement data may be used to characterize the wafer surface and / or to characterize or test previous processes performed on the wafer. Controlling the polishing process may include using displacement data to adjust handling controls and / or change the orientation in which the carrier head holds the wafer. Controlling the polishing process may also include using displacement data to apply varying amounts of pressure to the back surface of the wafer to compensate for curvature in the wafer when the wafer is pushed against the polishing pad. Some embodiments may also use displacement data to control other processes, such as the cleaning process.

[0071] The optional step of using displacement data to control a polishing or cleaning process performed on a wafer can be executed by the computer system of the corresponding polishing machine or cleaning machine. For example, software instructions on the computer system of the polishing machine may cause one or more processors to receive displacement data generated using a displacement sensor. As described above, the displacement data may indicate at least one area that is curved or bent on the wafer. These instructions may also cause the machine to identify parameters of the carrier head corresponding to a location on the area of ​​the wafer that is curved or bent. The computer system may then adjust the parameters of the carrier head to compensate for the area that is curved or bent on the wafer. As described above, these parameters may adjust the angle at which the carrier head grips the wafer, adjust the pressure applied during the polishing process, adjust the orientation of the wafer during the process, adjust the pressure applied to the back surface of the wafer using various chambers of the carrier head, and so on.

[0072] It should be recognized that the specific steps illustrated in FIG. 10 provide specific methods for measuring the displacement of wafers between semiconductor manufacturing processes according to various embodiments. According to alternative embodiments, different sequences of steps may also be performed. For example, alternative embodiments may perform the steps outlined above in a different order. Additionally, the individual steps illustrated in FIG. 10 may include a number of sub-steps that can be performed in various sequences appropriate to each individual step. Furthermore, additional steps may be added or removed depending on specific applications. Many variations, modifications, and alternatives are also within the scope of this disclosure.

[0073] Each of the methods described herein may be implemented by a computer system. Each step of these methods may be executed automatically by a computer system and / or may receive inputs / outputs involving a user. For example, a user may provide inputs for each step of the method, and each of these inputs may respond to a specific output requesting such input, wherein the output is generated by the computer system. Each input may be received in response to a corresponding requested output. Furthermore, inputs may be received from a user, received from another computer system as a data stream, retrieved from a memory location, retrieved via a network, requested from a web service, etc. Likewise, outputs may be provided to a user, provided to another computer system as a data stream, stored in a memory location, transmitted via a network, provided to a web service, etc. In short, each step of the methods described herein may be performed by a computer system and may involve any number of inputs, outputs, and / or requests to and from the computer system, with or without a user. Steps that do not involve a user may be described as being performed automatically by the computer system without human intervention. Accordingly, in light of this disclosure, it will be understood that each step of each method described herein may be modified to include inputs and outputs to and from a user, or that any decisions may be made by a processor and performed automatically by the computer system without human intervention. Furthermore, some embodiments of each of the methods described herein may be implemented as a set of instructions stored on a tangible non-transient storage medium to form a tangible software product.

[0074] FIG. 11 illustrates an exemplary computer system (1100) in which various embodiments may be implemented. The computer system (1100) may be used to implement any of the computer systems described above. For example, the computer system (1100) may be used to control a displacement sensor and to store displacement data. The computer system (1100) may also be used to transmit displacement data to other semiconductor manufacturing machines, such as a CMP machine or a cleaner. The CMP machine and / or cleaner may also include a computer system (1100) that uses displacement data to control a polishing and / or cleaning process.

[0075] As illustrated in the drawing, the computer system (1100) includes a processing unit (1104) that communicates with a plurality of peripheral subsystems via a bus subsystem (1102). These peripheral subsystems may include a processing acceleration unit (1106), an I / O subsystem (1108), a storage subsystem (1118), and a communication subsystem (1124). The storage subsystem (1118) includes tangible computer-readable storage media (1122) and system memory (1110).

[0076] The bus subsystem (1102) provides a mechanism for various components and subsystems of the computer system (1100) to communicate with each other as intended. Although the bus subsystem (1102) is schematically illustrated as a single bus, alternative embodiments of the bus subsystem may utilize multiple buses. The bus subsystem (1102) may be any of various types of bus structures, including a memory bus or memory controller, a peripheral bus, and a local bus using any of various bus architectures. For example, such architectures may include an Industry Standard Architecture (ISA) bus, a Micro Channel Architecture (MCA) bus, an Enhanced ISA (EISA) bus, a Video Electronics Standards Association (VESA) local bus, and a Peripheral Component Interconnect (PCI) bus, which can be implemented as a mezzanine bus manufactured according to the IEEE P1386.1 standard.

[0077] A processing unit (1104), which may be implemented as one or more integrated circuits (e.g., a conventional microprocessor or microcontroller), controls the operation of a computer system (1100). One or more processors may be included in the processing unit (1104). These processors may include single-core or multi-core processors. In certain embodiments, the processing unit (1104) may be implemented as one or more independent processing units (1132 and / or 1134) having single or multi-core processors included in each processing unit. In other embodiments, the processing unit (1104) may also be implemented as a quad-core processing unit formed by integrating two dual-core processors into a single chip.

[0078] In various embodiments, the processing unit (1104) may execute various programs in response to program code and may maintain a number of concurrently executed programs or processes. At any given time, some or all of the program codes to be executed may reside in the processor(s) (1104) and / or the storage subsystem (1118). Through appropriate programming, the processor(s) (1104) may provide the various functionalities described above. The computer system (1100) may additionally include a processing acceleration unit (1106) which may include a digital signal processor (DSP), a special purpose processor, etc.

[0079] The I / O subsystem (1108) may include user interface input devices and user interface output devices. User interface input devices may include pointing devices such as keyboards, mice, or trackballs, touchpads or touchscreens integrated into a display, scroll wheels, click wheels, dials, buttons, switches, keypads, audio input devices having voice command recognition systems, microphones, and other types of input devices. User interface input devices may include motion sensing and / or gesture recognition devices, such as a Microsoft Kinect® motion sensor, which enables users to control and interact with input devices, such as a Microsoft Xbox® 360 game controller, through a natural user interface using gestures and spoken commands. User interface input devices may also include eye gesture recognition devices, such as a Google Glass® blink detector, which detect eye activity from users (e.g., blinking while taking photos and / or making menu selections) and convert eye gestures into input for an input device (e.g., Google Glass®). Additionally, user interface input devices may include voice recognition detection devices that enable users to interact with voice recognition systems (e.g., Siri® Navigator) via voice commands.

[0080] User interface input devices may also, without limitation, include three-dimensional (3D) mice, joysticks or pointing sticks, gamepads and graphic tablets, and audio / visual devices, such as speakers, digital cameras, digital camcorders, portable media players, webcams, image scanners, fingerprint scanners, barcode readers, 3D scanners, 3D printers, laser rangefinders, and eye-tracking devices. Additionally, user interface input devices may include, for example, medical imaging input devices, such as computed tomography, magnetic resonance imaging, positional emission tomography, and medical ultrasound diagnostic devices. User interface input devices may also include, for example, audio input devices, such as MIDI keyboards, digital instruments, etc.

[0081] User interface output devices may include display subsystems, indicator lights, or non-visual displays, such as audio output devices. Display subsystems may be flat panel devices, projection devices, touchscreens, etc., such as using a cathode ray tube (CRT), liquid crystal display (LCD), or plasma display. Generally, the use of the term “output device” is intended to include all possible types of devices and mechanisms for outputting information from a computer system (1100) to a user or another computer. For example, user interface output devices may include, without limitation, various display devices that visually convey text, graphics, and audio / video information, such as monitors, printers, speakers, headphones, car navigation systems, plotters, voice output devices, and modems.

[0082] The computer system (1100) may include a storage subsystem (1118) comprising software elements shown as currently located within the system memory (1110). The system memory (1110) may store program instructions that are loadable and executable on the processing unit (1104), as well as data generated during the execution of these programs.

[0083] Depending on the configuration and type of the computer system (1100), the system memory (1110) may be volatile (e.g., random access memory (RAM)) and / or non-volatile (e.g., read-only memory (ROM), flash memory, etc.). RAM typically contains data and / or program modules that are immediately accessible to the processing unit (1104) and / or are currently being operated and executed by the processing unit (1104). In some embodiments, the system memory (1110) may include a number of different types of memory, such as static random access memory (SRAM) or dynamic random access memory (DRAM). In some embodiments, for example, a basic input / output system (BIOS) containing basic routines that help transfer information between elements within the computer system (1100) during startup may typically be stored in ROM. As an example not limited to, system memory (1110) also exemplifies application programs (1112), program data (1114), and operating systems (1116), which may include client applications, web browsers, intermediate layer applications, relational database management systems (RDBMS), etc.For example, the operating system (1116) may include various versions of Microsoft Windows®, Apple Macintosh®, and / or Linux operating systems, various commercially available UNIX® or UNIX-like operating systems (including, without limitation, various GNU / Linux operating systems, Google Chrome® OS, etc.) and / or mobile operating systems, such as iOS, Windows® Phone, Android® OS, BlackBerry® 10 OS, and Palm® OS operating systems.

[0084] The storage subsystem (1118) may also provide a computer-readable storage medium of a type for storing basic programming and data configurations that provide the functionality of some embodiments. Software (programs, code modules, instructions) that provides the functionality described above when executed by a processor may be stored in the storage subsystem (1118). These software modules or instructions may be executed by the processing unit (1104). The storage subsystem (1118) may also provide a storage for storing data used according to some embodiments.

[0085] The storage subsystem (1100) may also include a computer-readable storage medium reader (1120) that may be additionally connected to computer-readable storage media (1122). Together with the system memory (1110) and optionally in combination with them, the computer-readable storage media (1122) may comprehensively represent remote, local, fixed, and / or removable storage devices, in addition to storage media for temporarily and / or more permanently containing, storing, transmitting, and retrieving computer-readable information.

[0086] Computer-readable storage media (1122) containing code, or parts of code, may also include any suitable media, including storage media and communication media, such as but not limited to volatile and non-volatile, removable and non-removable media implemented in any method or technique for the storage and / or transmission of information. This may include tangible computer-readable storage media, such as RAM, ROM, electronically erasable programmable ROM (EEPROM), flash memory or other memory technology, CD-ROM, digital versatile disk (DVD), or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or other types of computer-readable media. This may also include intangible computer-readable media, such as any other media that can be used to transmit data signals, data transmissions, or desired information and can be accessed by a computing system (1100).

[0087] For example, computer-readable storage media (1122) may include a hard disk drive that reads from or writes to non-removable non-volatile magnetic media, a magnetic disk drive that reads from or writes to a removable non-volatile magnetic disk, and an optical disk drive that reads from or writes to a removable non-volatile optical disk, such as a CD-ROM, DVD, and Blu-Ray® disk, or other optical media. Computer-readable storage media (1122) may include, but are not limited to, Zip® drives, flash memory cards, universal serial bus (USB) flash drives, secure digital (SD) cards, DVD disks, digital video tapes, etc. Computer-readable storage media (1122) may also include solid-state drive (SSD)-based non-volatile memory, such as flash memory-based SSDs, enterprise flash drives, solid-state ROM, etc., SSD-based volatile memory, such as solid-state RAM, dynamic RAM, static RAM, DRAM-based SSDs, magnetoresistive RAM (MRAM) SSDs, and hybrid SSDs using a combination of DRAM and flash memory-based SSDs. Disk drives and their associated computer-readable media may provide non-volatile storage of computer-readable instructions, data structures, program modules, and other data for a computer system (1100).

[0088] The communication subsystem (1124) provides an interface to other computer systems and networks. The communication subsystem (1124) functions as an interface for receiving data from other systems and transmitting data from the computer system (1100) to other systems. For example, the communication subsystem (1124) can enable the computer system (1100) to be connected to one or more devices via the Internet. In some embodiments, the communication subsystem (1124) may include radio frequency (RF) transceiver components for accessing wireless voice and / or data networks (e.g., using cellular phone technology, advanced data network technology, such as 3G, 4G or EDGE (enhanced data rates for global evolution), WiFi (IEEE 802.11 family standards), or other mobile communication technologies, or any combination thereof), global positioning system (GPS) receiver components, and / or other components. In some embodiments, the communication subsystem (1124) may provide wired network connectivity (e.g., Ethernet) in addition to or instead of the wireless interface.

[0089] In some embodiments, the communication subsystem (1124) may also receive input communications in the form of structured and / or unstructured data feeds (1126), event streams (1128), event updates (1130), etc., on behalf of one or more users who can use the computer system (1100).

[0090] For example, the communication subsystem (1124) may be configured to receive data feeds (1126), such as Twitter® feeds, Facebook® updates, web feeds, such as RSS (Rich Site Summary) feeds, and / or real-time updates from one or more third-party information sources, in real time from users of other communication services and / or social networks.

[0091] Additionally, the communication subsystem (1124) may also be configured to receive data in the form of continuous data streams that may include event streams (1128) of real-time events and / or event updates (1130) that may be essentially continuous or unrestricted without an explicit end. Examples of applications that generate continuous data may include, for example, sensor data applications, financial tickers, network performance measurement tools (e.g., network monitoring and traffic management applications), clickstream analysis tools, automotive traffic monitoring, etc.

[0092] The communication subsystem (1124) may also be configured to output structured and / or unstructured data feeds (1126), event streams (1128), event updates (1130), etc., to one or more databases capable of communicating with one or more streaming data source computers coupled to the computer system (1100).

[0093] The computer system (1100) may be one of various types, including a handheld portable device (e.g., iPhone® cellular phone, iPad® computing tablet, PDA), a wearable device (e.g., Google Glass® head-mounted display), a PC, a workstation, a mainframe, a kiosk, a server rack, or any other data processing system.

[0094] Due to the ever-changing nature of computers and networks, the description of the computer system (1100) depicted in the drawings is intended merely as a specific example. Many other configurations are possible that have more or fewer components than the system depicted in the drawings. For example, custom hardware may also be used and / or specific elements may be implemented in hardware, firmware, software (including applets), or a combination thereof. Furthermore, connections to other computing devices, such as network input / output devices, may be utilized. Based on the disclosures and teachings provided herein, other ways and / or methods for implementing various embodiments should be apparent.

[0095] In the foregoing description, for the purposes of explanation, numerous specific details have been described to provide a complete understanding of the various embodiments. However, it will be apparent that some embodiments may be practiced without some of these specific details. In other cases, widely known structures and devices are illustrated in block diagram form.

[0096] The foregoing description provides only exemplary embodiments and is not intended to limit the scope, applicability, or configuration of the present disclosure. Rather, the foregoing description of various embodiments will provide enabling disclosure for implementing at least one embodiment. It should be understood that various changes may be made to the function and arrangement of elements without departing from the spirit and scope of some embodiments as described in the appended claims.

[0097] Specific details are provided in the foregoing description to provide a complete understanding of the embodiments. However, it will be understood that the embodiments may be practiced without these specific details. For example, circuits, systems, networks, processes, and other components may be illustrated as components in the form of block diagrams to avoid obscuring the embodiments from unnecessary details. In other cases, widely known circuits, processes, algorithms, structures, and technologies may be illustrated without unnecessary details to avoid obscuring the embodiments.

[0098] Additionally, it should be noted that individual embodiments may be described as processes depicted as flowcharts, flow diagrams, data flow diagrams, structure diagrams, or block diagrams. While a flowchart may describe operations as a sequential process, many of the operations may be performed in parallel or simultaneously. Furthermore, the order of operations may be rearranged. A process terminates when its operations are completed, but may have additional steps not included in the drawings. A process may correspond to a method, function, procedure, subroutine, subprogram, etc. If a process corresponds to a function, its termination may correspond to the return of the function to the calling function or the main function.

[0099] The term "computer-readable medium" includes, but is not limited to, portable or stationary storage devices, optical storage devices, wireless channels, and various other media capable of storing, containing, or transmitting instruction(s) and / or data. Code segments or machine-executable instructions may represent procedures, functions, subprograms, programs, routines, subroutines, modules, software packages, classes, or any combination of instructions, data structures, or program statements. Code segments may be coupled to other code segments or hardware circuits by transmitting and / or receiving information, data, arguments, parameters, or memory contents. Information, arguments, parameters, data, etc., may be transmitted, forwarded, or transmitted through any suitable means, including memory sharing, message passing, token passing, network transmission, etc.

[0100] Furthermore, embodiments may be implemented by hardware, software, firmware, middleware, microcode, hardware description languages, or any combination thereof. Where implemented in software, firmware, middleware, or microcode, program code or code segments for performing necessary tasks may be stored on a machine-readable medium. Processor(s) may perform the necessary tasks.

[0101] In the foregoing specification, features are described with reference to specific embodiments, but it should be recognized that not all embodiments are limited thereto. Various features and aspects of some embodiments may be used individually or together. Furthermore, the embodiments may be utilized in any number of environments and applications beyond those described herein without departing from the broader spirit and scope of this specification. Accordingly, the specification and drawings should be regarded as illustrative rather than restrictive.

[0102] Additionally, for the purposes of explanation, the methods have been described in a specific order. It should be recognized that in alternative embodiments, the methods may be performed in a different order than described. It should also be recognized that the methods described above may be embodied in sequences of machine-executable instructions that can be performed by hardware components or used to enable a machine, such as a general-purpose or special-purpose processor, to perform the methods, such as logic circuits programmed with instructions. These machine-executable instructions may be stored on one or more machine-readable media, such as CD-ROMs or other types of optical discs, floppy disks, ROMs, RAMs, EPROMs, EEPROMs, magnetic or optical cards, flash memory, or other types of machine-readable media suitable for storing electronic instructions. Alternatively, the methods may be performed by a combination of hardware and software.

Claims

Claim 1 A system comprising: a platform configured to support a wafer and to rotate the wafer around the center of the wafer; one or more displacement sensors positioned at a radius at a predetermined distance from the center of the wafer to measure the displacement of the wafer around the radius when the wafer is rotated; and a controller configured to receive displacement data from the one or more displacement sensors and use the displacement data to adjust the angle at which a carrier head grips the wafer during a polishing or cleaning process. Claim 2 A system according to claim 1, further comprising an alignment sensor positioned to detect a notch in the wafer when the wafer is rotated. Claim 3 In claim 2, the one or more displacement sensors include a laser displacement sensor; and the alignment sensor includes a through-beam sensor, the system. Claim 4 A system according to claim 1, wherein the one or more displacement sensors are also positioned to detect a notch in the wafer when the wafer is rotated. Claim 5 A system according to claim 1, wherein the one or more displacement sensors include a displacement sensor positioned on the wafer. Claim 6 A system according to claim 1, wherein the one or more displacement sensors include a displacement sensor positioned below the wafer. Claim 7 A system according to claim 1, wherein the one or more displacement sensors include a plurality of displacement sensors positioned along a radial line of the wafer. Claim 8 A system according to claim 1, wherein the one or more displacement sensors comprise a plurality of displacement sensors positioned at different rotational angles around the wafer. Claim 9 A method for measuring displacement of wafers between semiconductor manufacturing processes, comprising: a step of rotating the wafer around the center of the wafer; a step of generating displacement data representing the displacement of the wafer around the radius at a predetermined distance from the center of the wafer when the wafer is rotated; and a step of controlling a polishing process or a cleaning process performed on the wafer using the displacement data — the use of the displacement data includes adjusting the angle at which a carrier head holds the wafer during the polishing or cleaning process. Claim 10 A method for measuring the displacement of wafers between semiconductor manufacturing processes, wherein, in claim 9, the method further comprises the step of measuring the displacement of a baseline wafer to generate baseline displacement data representing a flat wafer surface. Claim 11 A method for measuring the displacement of wafers between semiconductor manufacturing processes, wherein the step of generating the displacement data includes the step of determining the displacement of the wafer relative to the baseline displacement data. Claim 12 A method for measuring displacement of wafers between semiconductor manufacturing processes, further comprising the step of mapping the displacement data to two-dimensional coordinates on the wafer based on alignment data in claim 9. Claim 13 A method for measuring displacement of wafers between semiconductor manufacturing processes, further comprising the step of mapping the displacement data to angles of rotation on the wafer based on alignment data in claim 9. Claim 14 A method for measuring displacement of wafers between semiconductor manufacturing processes, further comprising the steps of: identifying a displacement region on the wafer in the displacement data; and providing the displacement region to the polishing process or the cleaning process. Claim 15 A non-transient computer-readable medium comprising instructions, wherein the instructions, when executed by one or more processors, cause the one or more processors to perform operations including: receiving displacement data generated using a displacement sensor positioned at a radius at a predetermined distance from the center of the wafer with respect to the wafer—the displacement data indicates a displacement of the wafer around the radius, and the displacement data indicates a curved or bent area on the wafer—; identifying parameters of a carrier head corresponding to a location of the curved or bent area on the wafer—the carrier head is part of a chemical-mechanical polishing (CMP) machine or a wafer cleaning machine—and adjusting the parameters of the carrier head by adjusting the angle at which the carrier head grips the wafer to compensate for the curved or bent area on the wafer during a cleaning or polishing process. Claim 16 delete Claim 17 A non-transient computer-readable medium comprising instructions, wherein adjusting the parameters of the carrier head includes adjusting the amount of pressure provided to a curved or bent area on the wafer during the cleaning or polishing process. Claim 18 A non-transient computer-readable medium comprising instructions, wherein adjusting the amount of pressure comprises: identifying a chamber within the carrier head adjacent to a curved or bent region on the wafer; and adjusting the pressure within the chamber to compensate for the curved or bent region on the wafer. Claim 19 A non-transient computer-readable medium comprising instructions, wherein adjusting the amount of pressure includes adjusting the pressure at which a brush cleans a curved or bent area on the wafer during the cleaning process. Claim 20 In claim 15, the displacement data is a non-transient computer-readable medium comprising instructions generated using the displacement sensor by rotating the displacement sensor around the wafer.

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