Process control signals and index polishing for wafer uniformity

Abstract

A method for performing a polishing process on a substrate may include receiving the substrate in a known alignment within a carrier head of a polishing station for the polishing process. The polishing process may also involve polishing the substrate in the carrier head by a polishing pad on a platen such that the substrate passes over one or more sensors in the platen along one or more predetermined sensor paths relative to the known alignment of the substrate. The method may also include moving the carrier head to a first position based on one or more predetermined sensor paths, moving the platen to a second position based on one or more predetermined sensor paths, and rotating the substrate relative to the platen such that one or more sensors pass along one or more predetermined sensor paths.

Description

Technical Field

[0001] Cross - reference to related applications

[0001] This application claims the benefit and priority of U.S. Provisional Application No. 63 / 485,254, filed on February 15, 2023, entitled "INDEX POLISHING FOR PROCESS CONTROL SIGNAL AND WAFER UNIFORMITY", the content of which is incorporated herein by reference in its entirety for all purposes.

[0002]

[0002] This disclosure generally describes a method for polishing a semiconductor substrate. More specifically, this disclosure describes a method for aligning a substrate and controlling the movement of the substrate relative to sensors within a polishing station.

Background Art

[0003]

[0003] Substrates may be polished as part of a semiconductor manufacturing process. Due to the presence of multiple moving parts, sensors that detect the attributes of the substrate may make measurements at different locations on the substrate. The resulting signals have large errors and uncertainties and may lead to inaccurate readings.

Summary of the Invention

[0004]

[0004] A method of performing a polishing process on a substrate may include receiving the substrate within a carrier head of a polishing station with a known alignment for the polishing process. The polishing process may be such that the substrate within the carrier head is polished by a polishing pad on a platen such that the substrate passes over one or more sensors within the platen along one or more predetermined sensor paths relative to the known alignment of the substrate. The method may also include moving the carrier head to a first position based on one or more predetermined sensor paths, moving the platen to a second position based on one or more predetermined sensor paths, and rotating the substrate relative to the platen such that one or more sensors pass along one or more predetermined sensor paths. [Brief explanation of the drawing]

[0005] [Figure 1]

[0005] A substrate having multiple dies according to several embodiments. [Figure 2]

[0006] A substrate, a carrier head, and a platen according to several embodiments. [Figure 3]

[0007] This is a diagram of a platen and a substrate on a sensor path according to several embodiments. [Figure 4]

[0008] This is a graph showing measurement values ​​from a sensor according to several embodiments. [Figure 5]

[0009] A substrate and a set of predetermined sensor paths according to several embodiments. [Figure 6]

[0010] A substrate having a sensor path according to several embodiments. [Figure 7]

[0011] A substrate and a single predetermined sensor path according to several embodiments. [Figure 8]

[0012] A substrate and a single predetermined sensor path according to several embodiments. [Figure 9]

[0013] This is a graph showing measurement values ​​from a sensor according to several embodiments. [Figure 10]

[0014] This is a platen having an abrasive pad according to a specific embodiment. [Figure 11]

[0015] This is a flowchart of a method for performing a polishing process on a substrate according to several embodiments. [Figure 12]

[0016] This is an exemplary computer system according to several embodiments. [Modes for carrying out the invention]

[0006]

[0017] In semiconductor manufacturing, a substrate may comprise multiple dies arranged on the substrate. As part of the manufacturing process, one or more layers of films or other materials may be deposited on the substrate. One or more layers of films may be partially or completely removed by a polishing process using chemical mechanical polishing (CMP) equipment. Due to the precision nature of semiconductor manufacturing, the amount of films and / or other materials removed during the polishing process can be precisely controlled.

[0007]

[0018] During the polishing process, the substrate may be received by a CMP (Chemical Polishing) device at a carrier head. The platen may include a polishing pad and one or more sensors embedded in the platen. As the platen, carrier head, and substrate rotate, the polishing pad can apply slurry to the substrate and remove material. The sensors can detect the thickness of the substrate as the material is removed. However, because the substrate, carrier head, and platen are rotating, the sensors cannot follow the same path on the substrate in each path. As a result, the readings from the sensors may be inaccurate and inconsistent. Embodiments described herein solve this and other technical problems by indexing the substrate, carrier head, and / or platen with known alignments so that a predetermined sensor path can be tracked, thereby improving the accuracy of the polishing process.

[0008]

[0019] Figure 1 shows a substrate 102 having a plurality of dies 104a to n according to a particular embodiment. The substrate 102 may include silicon or other suitable material. The substrate 1002 may also include one or more films, such as photomasks used in semiconductor manufacturing processes.

[0009]

[0020] The multiple dies 104a-n may include chips such as integrated circuits, systems-on-a-chips, photovoltaic cells, and other such circuits. The dies may be of any size or arrangement. For example, die 104 may be laid out in a grid pattern on substrate 102, as shown in Figure 1. Alternatively, die 104a-n may be laid out in a different pattern depending on the size of die 104a-n. The pattern in which die 104 is arranged may also be determined based on other manufacturing concerns.

[0010]

[0021] Each die 104 may be associated with a set of attributes for their use. For example, one or more films may need to be completely or partially removed during the manufacturing process. Since the CMP equipment can apply the polishing process to various substrates with various dies, the amount of material removed may vary depending on the particular substrate and die arrangement. Similarly, the materials in the substrate and / or the films applied to the substrate may vary. Therefore, the rate at which these materials are removed during the polishing process may also vary. Thus, it may be desirable to determine an accurate measurement of the amount of material removed by the polishing process.

[0011]

[0022] Figure 2 shows a substrate 202, a carrier head 204, and a platen 106 according to a particular embodiment. The substrate 202 may be similar to the substrate 102 in Figure 1. Therefore, multiple dies may be arranged on the substrate 202. The substrate 202 may also contain one or more films that need to be completely or partially removed by a polishing process. The substrate 202 may be received by a CMP apparatus configured to apply a polishing process to the substrate 202.

[0012]

[0023] The CMP apparatus may also include a carrier head 204. The carrier head 204 may be configured to receive the substrate 202 and move the substrate 202 within the CMP apparatus. The carrier head 204 may also rotate or cause the substrate 202 to rotate. The carrier head 204 may have a home position within the CMP apparatus. The home position may provide a known reference point relative to the platen 106 and / or the CMP apparatus itself.

[0013]

[0024] The CMP apparatus may also include a platen 206. In some embodiments, the platen 206 may be larger than the substrate 202. The platen 206 may be configured to support a polishing pad 207. The polishing pad 207 can support a slurry used during the polishing process. The slurry may include polishing particles in a chemically reactive solution. When the platen 206 rotates, the slurry may polish the substrate 202 and remove material chemically via mechanical means (polishing particles) and / or the chemically reactive solution. In some embodiments, the polishing pad 207 may be offset from the platen 206. For example, a first axis of the polishing pad may be parallel to a corresponding axis of the platen 206 and may be translated a distance along a second axis perpendicular to the first axis.

[0014]

[0025] The platen 206 may also include one or more sensors 208a - c. The one or more sensors 208a - c may be arranged at regular intervals with respect to the platen 206. For example, if there are three sensors 108a - c, each of the sensors 108a - c may be placed at a position 120° with a constant radial distance from the center of the platen 206. In the case of four sensors, each sensor may be placed every 90°. Other configurations may also be used at different radial distances and / or placed at different angular intervals around the platen 206.

[0015]

[0026] One or more sensors 108a-c may include electrical sensors, optical sensors, or other suitable detection devices. One or more sensors 108a-c may be used to detect one or more attributes of the substrate 202 and / or the die placed on the substrate 202 (such as the thickness of the substrate 202 or the film on the substrate 202). By determining the thickness of the film on the substrate 202, one or more sensors 108a-c can be used to determine the amount of material removed during the polishing process. As the substrate 202 and the platen 206 rotate relative to each other, one or more sensors 108a-c can follow one or more sensor paths across the substrate 202 (and the die placed thereon). Measurements made by one or more sensors 108a-c may differ based on where the individual measurements are made along the sensor path on the substrate 202. Therefore, even when made by the same sensor, the measurements may have a high degree of variability.

[0016]

[0027] Figure 3 shows a diagram of the platen 306 and the substrate 302 on the sensor paths 310a-c according to a particular embodiment. The substrate 302 may be similar to the substrate 102 in Figure 1. Therefore, multiple dies may be arranged on the substrate 302. The substrate 302 may also contain one or more films that need to be completely or partially removed by the polishing process. The substrate 302 may be supported by a carrier head similar to the carrier head 204 in Figure 2. The substrate 302, platen 306, and carrier head may be randomly aligned. The carrier head may rotate, or the substrate 302 may rotate with respect to the platen 306. For example, the substrate 302 is usually loaded onto the carrier head of the CMP apparatus in a random orientation. Furthermore, the CMP apparatus may start the polishing process with the carrier head in its home location or at a random location. Prior to this disclosure, the orientation and location of the substrate 302 and carrier head were not specifically adjusted based on the desired path of the sensor.

[0017]

[0028] Platen 306 may be similar to platen 206 of FIG. 2. Thus, platen 306 is included in the CMP apparatus and may include one or more sensors 308a - c. The one or more sensors 308a - c may include electrical sensors, optical sensors, or other suitable detection devices, and sensors 308a - c may be placed at regular intervals with respect to platen 306. Platen 306 may also support a polishing pad that contains slurry. The polishing pad and / or slurry may remove material from substrate 302 during the polishing process.

[0018]

[0029] During the polishing process, platen 306 may rotate at a first rotational speed. The carrier head and / or substrate 202 may rotate at a second rotational speed. Due to the first rotational speed and the second rotational speed, as well as the random orientation of substrate 302 with respect to platen 306, the one or more sensors 308a - c may follow one or more sensor paths 310a - c across substrate 302 via unregulated or undetermined paths. For example, if substrate 302 and platen 306 are not aligned, the one or more sensor paths 310a - c may move across different portions of substrate 302 each time they pass through. Since the one or more sensors 308a - c may move along different sensor paths, measurements by the one or more sensors 308a - c may be taken at inconsistent locations.

[0019]

[0030] For example, sensor path 310a may represent measurements taken by sensor 308a at a first time. Sensor 308a may be able to cross a first set of dies on substrate 302 along sensor path 310a. The signal quality associated with measurements by sensor 308 may vary depending on the location where the measurement is taken. If the measurement is taken at the boundary between dies, the signal quality may be minimized. If the measurement is taken at the center of a die in the first set of dies, the signal quality may be maximized. Generally, the closer the measurement is taken to the center of the die, the higher the signal quality may be.

[0020]

[0031] Sensor path 310b may represent a measurement taken by sensor 308a at a second time. Sensor 308a may traverse a second set of dies on substrate 302. The second set of dies may include some or all of the dies included in the first set of dies, or it may be a completely different set of dies. In either case, sensor path 310b may vary significantly from sensor path 310a. Therefore, measurements taken along sensor path 310b may differ from measurements taken along sensor path 310a. Similar variability may be observed in measurements taken along sensor path 310c.

[0021]

[0032] Figure 4 shows a graph 400 representing sensor measurements according to a specific embodiment. Graph 400 may represent measurements taken by the sensor during the polishing process. The sensor may be similar to sensor 308a in Figure 3. The sensor may be used to determine the thickness of a substrate similar to substrate 102 in Figure 1. The thickness may be used to determine the amount of material removed during the polishing process.

[0022]

[0033] Graph 400 can be generated during a polishing process in which the substrate, platen, and carrier head are in random alignment, as described in Figure 3. Because the substrate, carrier head, and platen are in random alignment, one or more sensor paths similar to one or more sensor paths 310a-c may have a high degree of variability, as measurements may be taken at different locations on the substrate at different times.

[0023]

[0034] Looking at Graph 400, general trends can be identified. For example, peaks in signal quality (representing substrate thickness) may occur at approximately +50mm, -50mm, +75mm, etc. Dips in signal quality may be observed at 0mm, +25mm, +140mm, etc. Peaks may represent signals recorded by sensors traversing sensor paths that pass through a consistent or central portion of each die, rather than at the boundaries between dies on the substrate. Conversely, dips may represent areas where the sensor path traverses the boundaries between dies.

[0024]

[0035] Despite the identification of general trends, Graph 400 can represent a high degree of variability. For example, at approximately -120 mm, the maximum measured thickness could be approximately 330 mm. At the same location, the minimum thickness could be 220 micrometers. This variability can represent approximately 33% uncertainty. This level of uncertainty may be unacceptable for certain precision applications.

[0025]

[0036] To obtain more accurate measurements, the substrate, carrier head, and platen may be aligned before the start of the polishing process. The substrate may include a reference point at a location on the substrate. The substrate may be aligned before being placed in the CMP apparatus. For example, the substrate may be placed in a known alignment within a forward-opening unified pod (FOUP). The substrate may then be placed on the carrier head of the CMP apparatus while maintaining the known alignment.

[0026]

[0037] The carrier head can move to a corresponding home position within the CMP apparatus. Similarly, the platen can move to a corresponding home position. Since the carrier head and platen are in their corresponding home positions and the substrate is in a known alignment, the substrate, carrier head, and platen can be aligned with each other. When the substrate, carrier head, and platen are aligned with each other, one or more predetermined sensor paths can be calculated so that the one or more sensor paths are consistent and pass through locations on the substrate aligned with the die center rather than the die boundary.

[0027]

[0038] Various parameters may be used to determine one or more predetermined sensor paths. For example, an ideal path may be determined for a particular arrangement of dies on a substrate. An ideal sensor path can maximize the signal quality of sensor measurements by crossing the maximum number of dies at or near the center of the dies. Additionally or alternatively, an ideal sensor path can maximize the number of boundaries between dies that are crossed vertically.

[0028]

[0039] In some embodiments, one or more sensor paths may be determined as associated sensors. For example, a first predetermined sensor path may be associated with a first sensor, and a second predetermined sensor path may be associated with a second sensor. The first and second predetermined sensor paths may be independent of each other. In another embodiment, one or more predetermined sensor paths may be determined so that one or more sensors pass along the same predetermined sensor path. One or more sensors may alternate so that each passes along the predetermined sensor path at different times at regular intervals. In yet another embodiment, there may be multiple predetermined sensor paths. One or more sensors may repeatedly pass along each of the multiple predetermined sensor paths.

[0029]

[0040] The first rotational speed of the platen and the second rotational speed of the substrate may be used to align one or more predetermined sensor paths. In some embodiments, the first and second rotational speeds may be the same (e.g., 90 rpm). In other embodiments, the first and second rotational speeds may be different (e.g., 45 rpm and 120 rpm, respectively). Furthermore, the first and second rotational speeds may be in the same direction (e.g., clockwise) or in alternating directions.

[0030]

[0041] This technique can generate repeatable sensor paths for each path of one or more sensors, so that signals are collected at predetermined locations throughout the polishing process. Signals from each scan can be directly compared, reducing uncertainty between measurements. Substrate thickness can be monitored with each rotation of the substrate and / or platen. More specifically, this technique can generate repeatable sensor traces for each scan so that signals are collected at predetermined locations throughout the polishing process. Signals from each scan can be directly compared, and thickness can be monitored with each rotation. Eliminating deviations between scans significantly improves endpoint robustness.

[0031]

[0042] The indexing of the polishing process may include one or more of the following steps: First, the substrate may be aligned to a known position. For example, the substrate may often have notches or other visual references indicating a known position on the substrate. The location of the reference may be determined before loading the substrate onto the carrier head. This makes it possible to load the substrate onto the carrier head in a known position relative to the carrier head. As will be explained in detail below, this makes it possible to align the sensor path across the substrate with the dies on the substrate. For example, the substrate may be rotated so that the sensor path follows through the central portion of each die rather than along the boundary between dies.

[0032]

[0043] The controller of a CMP device may include a computer-readable non-temporary storage medium for storing instructions. These instructions may be part of a recipe or other command sequence used to control the operation of the CMP device. When one or more processors of the controller execute these instructions, the controller can move the carrier head to the home position and / or rotation. Similarly, the controller can rotate the platen to the origin. In some embodiments, the polishing process may also include rotating the platen to a first rotation away from the origin rotation. Similarly, the process may also include moving the rotation and / or position of the carrier head to a first rotation and / or position away from the home rotation and / or position. This allows the CMP device to rotate and position the substrate relative to the sensor at a known position and / or rotation. In any case, this ensures that the platen and carrier head are in known locations before each polishing process.

[0033]

[0044] Next, the recipe may rotate the carrier head and / or platen at a predetermined rotational speed (e.g., revolutions per minute) selected based on a predetermined sensor path. For example, in some embodiments, a fixed rotational speed of the platen (e.g., 90 rpm) may be used, as this speed typically determines the rate at which the film is removed from the substrate. In some embodiments, the rotational speed of the carrier head may be set to be approximately the same as the rotational speed of the platen (e.g., 90 rpm). Alternatively, the rotational speed of the carrier head may be slightly greater or less than the rotational speed of the platen (e.g., platen rotational speed 93 RPM and carrier head rotational speed 87 RPM). However, a custom rotational speed may be determined to generate a predetermined sensor path. Specifically, rather than simply selecting the rotational speeds of these components to generate a random sensor path, a predetermined sensor path may be used as the starting point for this process, and the rotational speeds of the platen and carrier head relative to each other may be selected to generate the predetermined sensor path.

[0034]

[0045] Several different sensor paths are provided below as examples. Sensor paths can be generated using specific rotational speeds of the carrier head and / or platen, as described below. For example, one of the following sensor paths can be selected, and the known rotational speeds associated with that sensor path can be used in the recipe. Alternatively, new sensor paths not explicitly shown below can be developed, and other sensor paths can be generated using geometric calculations. For example, since the starting positions of the substrate, carrier head, and platen are known along with a given sensor path, the rotational speeds of these components can be calculated by solving known geometric rotation equations that calculate their relative motion. The following figures show exemplary sensor paths across the substrate determined by the techniques described herein. The examples are not exhaustive, and many other different paths, not explicitly shown here, may also be used. Based on the die layout on the substrate, other sensor paths may be selected to maximize signal quality. The starting direction of the substrate, and the rotational speeds of the platen and carrier head can then be adjusted to match the given sensor path.

[0035]

[0046] Figure 5 shows a substrate 502 and a set of predetermined sensor paths 510a-c according to several embodiments. The substrate 502 may be similar to the substrate 102 in Figure 1. Thus, the substrate 502 may include a plurality of dies 504a-n. The substrate 502 may have a known alignment determined by a photodetector or other suitable method. The substrate 502 may be received by the carrier head of a CMP apparatus according to the known alignment. The carrier head may be similar to the carrier head 204 in Figure 2.

[0036]

[0047] The carrier head can support the substrate 502 on a platen similar to the platen 206 in Figure 2. The platen may support a polishing pad and / or slurry and may include one or more sensors, such as one or more sensors 208a-c in Figure 2. The substrate 502, carrier head, and platen can rotate as described with respect to Figure 3. In Figure 3, the substrate 302, carrier head, and platen 306 may not be aligned. However, here the substrate 502 may be in a known alignment, and the carrier head and platen may be moved to their respective home positions. Thus, the substrate 502, carrier head, and platen can be aligned with respect to each other. Thus, a predetermined sensor path 510a-c can be determined by aligning the substrate 502 and rotating / positioning the carrier head on the platen with respect to the sensor positions. The predetermined sensor path 510a-c can then be implemented by rotating the substrate 502 at a first rotational speed and the platen at a second rotational speed (e.g., 90 rpm and 90 rpm, respectively). The first and second rotational speeds can be calculated so that the sensor traverses these same paths each time the substrate 502 passes over the sensor. This may be in contrast to a CMP process that does not calculate rotational speed based on the sensor path, and therefore the sensor traverses a different path each time it passes under the substrate 502.

[0037]

[0048] A predetermined sensor path 510a can traverse a first set of dies on the substrate 502. A predetermined sensor path 510a can traverse the center or vicinity of a first number of dies. A predetermined sensor path 510b can traverse a second set of dies on the substrate 502. A predetermined sensor path 510b can traverse the center or vicinity of a second number of dies. A predetermined sensor path 510c can traverse a third set of dies on the substrate 502. A predetermined sensor path 510c can traverse the center or vicinity of a third number of dies. These sensor paths may be selected to maximize the number of dies for which the path traverses the center or vicinity of the dies.

[0038]

[0049] In some embodiments, the number of centers traversed by each of the predetermined sensor paths 510a to c can provide an acceptable signal quality. Each of the predetermined sensor paths 510a to c can then be used by one or more sensors. Each of the one or more sensors can travel along a specific predetermined sensor path 510a to c, or one or more sensors can travel along all of the predetermined sensor paths at different times.

[0039]

[0050] In other embodiments, only one of the predetermined sensor paths 510a to c may provide acceptable signal quality. For example, a predetermined sensor path 510a may coincide with the boundaries between a very large number of dies and / or be too far from the centers of a very large number of dies. A predetermined sensor path 510c may have similar defects. A predetermined sensor path 510b may cross a threshold number of dies at or near the center. Furthermore, a predetermined sensor path 510b may also cross the boundaries between dies substantially perpendicularly. Thus, a predetermined sensor path 510b may be selected as the desired sensor path. One or more of the sensors can then pass along the predetermined sensor path 510b during the polishing process.

[0040]

[0051] Figure 6 shows a substrate 602 having sensor paths 610a-b according to several embodiments. The substrate 602 may be similar to the substrate 102 in Figure 1. The substrate 602 may be in a known alignment determined by a photodetector or other suitable method. The substrate 602 may be received by a carrier head of a CMP apparatus according to the known alignment. The carrier head may be similar to the carrier head 204 in Figure 2.

[0041]

[0052] The carrier head can support the substrate 602 on a platen similar to the platen 206 in Figure 2. The platen supports the polishing pad and / or slurry and may include one or more sensors, such as one or more sensors 208a-c in Figure 2. Similar to the substrate 502 in Figure 5, the substrate 602, carrier head, and platen can be aligned with respect to each other so that predetermined paths 610a-c can be determined.

[0042]

[0053] In some embodiments, a predetermined sensor path 610a-c may be a set of straight lines crossing the substrate 602 at a given interval (e.g., 60°). Each of the predetermined sensor paths 610a-c may cross a certain number of dies at or near the center of each die so as to maximize the signal quality of the measurements taken along the predetermined sensor path 610a-c. The predetermined sensor paths 610a-c may also cross a certain number of boundaries between dies substantially perpendicularly. The predetermined sensor paths 610a-c may be implemented by rotating the substrate 602 at a first rotational speed and the platen at a second rotational speed (e.g., 45 rpm and 90 rpm, respectively).

[0043]

[0054] In some embodiments, one or more sensors can travel along corresponding paths of predetermined sensor paths 610a to c. In other embodiments, each of one or more sensors can travel along each of the predetermined sensor paths 610a to c at different times. The predetermined sensor paths 610a to c may provide larger sample size measurements by measuring the attributes of more dies on the substrate 602 than a single predetermined sensor path.

[0044]

[0055] Figure 7 shows a substrate 702 and a single predetermined sensor path 710 according to several embodiments. The substrate 702 may be similar to the substrate 102 in Figure 1. The substrate 702 may be in a known alignment determined by a photodetector or other suitable method. The substrate 702 may be received by a carrier head of a CMP apparatus according to the known alignment. The carrier head may be similar to the carrier head 204 in Figure 2.

[0045]

[0056] The carrier head can support the substrate 702 on a platen similar to the platen 206 in Figure 2. The platen supports the polishing pad and / or slurry and may include one or more sensors, such as one or more sensors 208a-c in Figure 2. Similar to the substrate 502 in Figure 5, the substrate 702, the carrier head, and the platen can be aligned with respect to each other so that a predetermined path 710 can be determined.

[0046]

[0057] In some embodiments, a large rpm difference between the platen and the substrate 702 may not affect the manufacturing or polishing process. In such cases, a predetermined sensor path 710 may be an ideal sensor path. The predetermined sensor path 710 may maximize the signal quality of measurements performed by one or more sensors as one or more sensors pass along the predetermined sensor path 710. As shown in Figure 7, the predetermined sensor path 710 may generate multiple identical arcs across the substrate 702 at different times. In other words, the predetermined sensor path 710 may include a single shape that follows across the substrate 702 at different locations at different times. The predetermined sensor path 710 may be implemented by rotating the substrate 702 at a first rotational speed and the platen at a second rotational speed (e.g., 67.5 rpm and 90 rpm, respectively).

[0047]

[0058] In some embodiments, one or more sensors may travel along the relevant path of a predetermined sensor path 710. In other embodiments, each of the one or more sensors may travel along each of the predetermined sensor paths 710 at different times, with one sensor following another after a delay. Thus, the predetermined sensor path 710 may provide larger sample size measurements by measuring the attributes of more dies on the substrate 702 by repeating the predetermined sensor path 710 at different locations.

[0048]

[0059] Figure 8 shows a substrate 802 and a single predetermined sensor path 810 according to a particular embodiment. Substrate 802 may be similar to substrate 102 in Figure 1. Substrate 802 may be in a known alignment determined by a photodetector or other suitable method. Substrate 802 may be received by a carrier head of a CMP apparatus according to the known alignment. The carrier head may be similar to carrier head 204 in Figure 2.

[0049]

[0060] The carrier head can support the substrate 802 on a platen similar to the platen 206 in Figure 2. The platen supports the polishing pad and / or slurry and may include one or more sensors, such as one or more sensors 208a-c in Figure 2. Similar to the substrate 502 in Figure 5, the substrate 802, carrier head, and platen can be aligned with respect to each other so that a predetermined path 810 can be determined.

[0050]

[0061] In some embodiments, a large rpm difference between the platen and the substrate 802 may not affect the manufacturing or polishing process. In such cases, a predetermined sensor path 810 may be an ideal sensor path. The predetermined sensor path 810 may maximize the signal quality of measurements performed by one or more sensors as one or more sensors pass along the predetermined sensor path 810. As shown in Figure 8, the predetermined sensor path 810 may generate multiple identical arcs across the substrate 802 at different times. In other words, the predetermined sensor path 810 may include a single shape that follows across the substrate 802 at different locations at different times. The predetermined sensor path 810 may be implemented by rotating the substrate 802 at a first rotational speed and the platen at a second rotational speed (e.g., 135 rpm and 90 rpm, respectively).

[0051]

[0062] In some embodiments, one or more sensors may travel along the relevant path of a predetermined sensor path 810. In other embodiments, each of the one or more sensors may travel along each of the predetermined sensor paths 810 at different times, with one sensor following another after a delay. Thus, the predetermined sensor path 810 may provide larger sample size measurements by measuring the attributes of more dies on the substrate 802 by repeating the predetermined sensor path 810 at different locations.

[0052]

[0063] Figure 9 shows a graph 900 representing sensor measurements in several embodiments. Graph 900 may represent measurements taken by the sensor during the polishing process. The sensor may be similar to sensor 308a in Figure 3. The sensor may be used to determine the thickness of a substrate similar to substrate 102 in Figure 1. The thickness may be used to determine the amount of material removed during the polishing process.

[0053]

[0064] Sensor measurements may be performed according to the techniques described herein, in which the substrate, carrier head, and platen are aligned (or indexed). Thus, graph 900 can be generated for each sensor path by a predetermined repeatable sensor path. Signals can be collected at predetermined locations throughout the polishing process. Signals from each scan can be directly compared, reducing uncertainty between measurements.

[0054]

[0065] Returning briefly to Figure 4, an uncertainty of approximately 33% may be observed. In contrast, Graph 900 may not show easily recognizable deviations. Therefore, measurements performed during the polishing process using the techniques described above may be more reliable than measurements performed without indexing of the substrate, carrier head, and platen. Because the measurements may be more reliable, higher precision may be achieved during the polishing process.

[0055]

[0066] Figure 10 shows a platen 1006 having a polishing pad 1012 according to a particular embodiment. Platen 1006 may be similar to platen 206 in Figure 2. Platen 206 may support the polishing pad 1012. The polishing pad 1012 may include one or more grooves 1014a-b. Although only two grooves 1014a-b are illustrated, any number of grooves 1014a-b may be present. The grooves 1014a-b receive the slurry and allow the slurry to flow through the grooves 1014a-b. The slurry may contain abrasive particles in a chemically reactive solution so that a substrate, such as a substrate 1016, can be polished as the slurry flows through the grooves 1014a-b.

[0056]

[0067] The platen 1006 may include a shaft 1020. The polishing pad 1012 may include a corresponding shaft 1022 parallel to the shaft 1020. When the polishing pad 1012 is placed on the platen 1006, the polishing pad 1012 may be offset with respect to the platen 1006 such that the corresponding shaft 1022 is parallel to the shaft 1020 but offset by some amount.

[0057]

[0068] Since the polishing pad 1012 is offset from the platen 1006, the slurry in grooves 1014a-b may sweep or wobble along the radial direction of the platen 1006 as the platen 1006 rotates. Thus, the slurry may come into contact with the substrate 1016 (such as substrate 202 in Figure 2) and polish the substrate 1016 in one or more dimensions. For example, the slurry may polish an arc across the substrate as grooves 1014a-b rotate with respect to the substrate 1016. Grooves 1014a-b may also move radially with respect to the substrate 1016 due to the wobble caused by the offset of the polishing pad 1012. This can lead to higher precision and / or efficiency during the polishing process, especially when the polishing process is performed in a short time. By utilizing the platen indexing process described above, the grooves 1022 of the polishing pad start from the same location. This ensures that the same slurry flow field is observed across different wafers. This also improves the consistency of measurements between different wafers polished with the same device.

[0058]

[0069] Figure 11 shows a flowchart of Method 1100 for performing a polishing process on a substrate according to a particular embodiment. Method 1100 may be performed by some or all of the systems disclosed herein, such as those described with respect to Figure 2. In step 1102, Method 1100 may include receiving the substrate in a known alignment. The substrate may be received by a carrier head of a polishing station for the polishing process. The substrate may be similar to substrate 102 in Figure 1. Therefore, multiple dies may be arranged on the substrate. The substrate may also contain one or more films that need to be completely or partially removed by the polishing process. The carrier head may be configured to rotate or to rotate the substrate.

[0059]

[0070] The polishing process allows the substrate in the carrier head to be polished by a polishing pad on the platen. As shown in Figure 10, the grooves of the polishing pad may be offset from the corresponding axis of the platen. During the polishing process, the substrate can pass over one or more sensors in the platen along one or more predetermined sensor paths relative to a known alignment of the substrate.

[0060]

[0071] One or more sensors may be similar to one or more sensors 208a-c. One or more sensors may include electrical sensors, optical sensors, or other suitable detection devices, and may be mounted at regular intervals with respect to the platen. One or more predetermined sensor paths may be determined to maximize the signal quality associated with one or more of the one or more sensors. Signal quality may be maximized by having one or more sensor paths cross the center of the maximum number of dies and / or substantially perpendicularly cross the boundary of the maximum number of dies.

[0061]

[0072] In step 1104, method 1100 may include moving the carrier head to a first position based on one or more predetermined sensor paths. The first position may be the same as the associated home position of the carrier head in the CMP apparatus. In step 1106, the method may include moving the platen to a second position based on one or more predetermined sensor paths. The second position may be the same as the associated home position of the platen, as described in Figure 2. Using known alignments of the substrate, the first position of the carrier head, and the second position of the platen, the techniques and methods described herein can be implemented.

[0062]

[0073] In step 1106, method 1100 may include rotating the substrate relative to the platen so that one or more sensors pass along one or more predetermined sensor paths. In some embodiments, a first rotational speed may be associated with the platen and determined based on one or more sensor paths. A second rotational speed may be associated with the substrate and determined based on one or more sensor paths. The first and second rotational speeds may be the same or different (e.g., both 90 rpm, or 135 rpm and 90 rpm, respectively). For example, the first and second rotational speeds may be used to implement any of the predetermined sensor paths shown in Figures 5-8.

[0063]

[0074] Figure 12 shows an exemplary computer system 1200 according to a particular embodiment. System 1200 may be used to implement any of the computer systems, methods, or techniques described above. For example, computer system 1200 may be used to perform method 1100 of Figure 1. As shown in Figure 12, computer system 1200 includes a processing unit 1204 that communicates with several peripheral subsystems via a bus subsystem 1202. These peripheral subsystems may include a processing acceleration unit 1206, an I / O subsystem 1208, a storage subsystem 1218, and a communication subsystem 1224. The storage subsystem 1218 includes a tangible computer-readable storage medium 1222 and system memory 1210.

[0064]

[0075] The bus subsystem 1202 provides a mechanism for various components and subsystems of the computer system 1200 to communicate with each other as intended. Although the bus subsystem 1202 is schematically shown as a single bus, alternative embodiments of the bus subsystem may utilize multiple buses. The bus subsystem 1202 may be one of several types of bus structures, including a memory bus or memory controller, a peripheral bus, and a local bus using one of various bus architectures. For example, such architectures may include an Industry Standard Architecture (ISA) bus, a Microchannel Architecture (MCA) bus, an Extended ISA (EISA) bus, a Video Electronics Standards Institute (VESA) local bus, and a Peripheral Component Interconnect (PCI) bus, which may be implemented as a mezzanine bus manufactured to the IEEE P1386.1 standard.

[0065]

[0076] The processing unit 1204, which can be implemented as one or more integrated circuits (e.g., conventional microprocessors or microcontrollers), controls the operation of the computer system 1200. One or more processors may be included within the processing unit 1204. These processors may include single-core processors or multi-core processors. In certain embodiments, the processing unit 1204 may be implemented as one or more independent processing units 1232 and / or 1234, each processing unit may include a single processor or a multi-core processor. In other embodiments, the processing unit 1204 may also be implemented as a quad-core processing unit formed by integrating two dual-core processors onto a single chip.

[0066]

[0077] In various embodiments, the processing unit 1204 can execute various programs in response to program code and can maintain multiple programs or processes running simultaneously. At a given time, some or all of the program code to be executed may reside in the processor(s) 1204 and / or in the memory subsystem 1218. Through appropriate programming, the processor(s) 1204 can provide the various functions described above. The computer system 1200 may further include a processing acceleration unit 1206, which may include a digital signal processor (DSP), a dedicated processor, and the like.

[0067]

[0078] The I / O subsystem 1208 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 displays, scroll wheels, click wheels, dials, buttons, switches, keypads, audio input devices with voice command recognition systems, microphones, and other types of input devices.

[0068]

[0079] User interface input devices may also include, but are not limited to, three-dimensional (3D) mice, joysticks or pointing sticks, gamepads and graphic tablets, 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. Furthermore, user interface input devices may also include medical imaging input devices, such as computed tomography, magnetic resonance imaging, positional emission tomography, and medical ultrasound imaging devices. User interface input devices may also include audio input devices, such as MIDI keyboards and digital musical instruments.

[0069]

[0080] User interface output devices may include non-visual displays such as display subsystems, indicator lights, or audio output devices. Display subsystems may include flat panel devices such as those using cathode ray tubes (CRTs), liquid crystal displays (LCDs), or plasma displays, projection devices, touchscreens, etc. In general, the use of the term “output device” is intended to include all conceivable types of devices and mechanisms for outputting information from the computer system 1200 to a user or another computer. For example, user interface output devices may include, but are not limited to, a variety of display devices that visually convey text, graphics, and audio / video information, such as monitors, printers, speakers, headphones, car navigation systems, plotters, audio output devices, and modems.

[0070]

[0081] The computer system 1200 may include a storage subsystem 1218 containing software elements that are currently located in the system memory 1210. The system memory 1210 may store program instructions that can be loaded and executed on the processing unit 1204, as well as data generated during the execution of these programs.

[0071]

[0082] Depending on the configuration and type of the computer system 1200, the system memory 1210 may be volatile (such as random access memory (RAM)) and / or non-volatile (such as read-only memory (ROM), flash memory, etc.). RAM typically contains readily accessible data and / or program modules and / or are currently being operated and executed by the processing unit 1204. In some embodiments, the system memory 1210 may include several different types of memory, such as static random access memory (SRAM) or dynamic random access memory (DRAM). In some embodiments, a basic input / output system (BIOS), which includes basic routines that help transfer information between elements within the computer system 1200, such as during startup, may be stored, typically in ROM. As an example, but not an limitation, the system memory 1210 may also include application programs 1212, program data 1214, and an operating system 1216, which may include client applications, web browsers, intermediate-tier applications, relational database management systems (RDBMS), etc. For example, Operating System 1216 may include various versions of Microsoft Windows®, Apple Macintosh®, and / or Linux operating systems, various commercially available UNIX® or UNIX-like operating systems (including, but not limited to, various GNU / Linux operating systems, Google Chrome® OS, etc.), and / or mobile operating systems such as iOS, Windows® Phone, Android® OS, BlackBerry® 12 OS, and Palm® OS.

[0072]

[0083] The storage subsystem 1218 may also provide a tangible (non-temporary) computer-readable storage medium for storing basic programming and data structures that provide the functionality of several embodiments. Software (programs, code modules, instructions) that, when executed by the processor, provides the above-mentioned functionality may be stored in the storage subsystem 1218. These software modules or instructions may be executed by the processing unit 1204. The storage subsystem 1218 may also provide a repository for storing data used according to several embodiments.

[0073]

[0084] The storage subsystem 1218 may also include a computer-readable storage medium reader 1220, which may be further connected to the computer-readable storage medium 1222. Together with the system memory 1210, and optionally in combination with the system memory 1210, the computer-readable storage medium 1222 may comprehensively represent remote, local, fixed, and / or removable storage devices and storage media for storing, transmitting, and retrieving computer-readable information, both temporarily and / or more permanently.

[0074]

[0085] The computer-readable storage medium 1222 containing code or a portion of code may also include, but is not limited to, any suitable medium, including storage and communication media, such as volatile and non-volatile, removable and non-removable media, which are implemented in any method or technique for storing and / or transmitting information. This may include tangible computer-readable storage media or other tangible computer-readable media, such as RAM, ROM, electronically erasable programmable ROM (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile disk (DVD) or other optical storage, magnetic cassette, magnetic tape, magnetic disk storage or other magnetic storage devices. This may also include non-tangible computer-readable media, such as any other medium which may be used to transmit data signals, data transmission or desired information and which may be accessed by the computing system 1200.

[0075]

[0086] For example, computer-readable storage media 1222 may include hard disk drives that read from or write to non-removable non-volatile magnetic media, magnetic disk drives that read from or write to removable non-volatile magnetic disks, and optical disk drives that read from or write to removable non-volatile optical disks, such as CD-ROMs, DVDs, and Blu-ray® discs, or other optical media. Computer-readable storage media 1222 may also include, but are not limited to, Zip® drives, flash memory cards, Universal Serial Bus (USB) flash drives, Secure Digital (SD) cards, DVD discs, digital videotapes, and the like. Computer-readable storage media 1222 also include SSDs (solid-state drives) based on non-volatile memory, such as SSD-based flash memory, enterprise flash drives, solid-state ROMs, etc., and SSDs based on volatile memory, such as solid-state RAM, dynamic RAM, static RAM, DRAM-based SSDs, magnetoresistive RAM (MRAM) SSDs, etc. This may include hybrid SSDs that use a combination of DRAM-based SSDs and flash memory-based SSDs. Disk drives and their associated computer-readable media may provide non-volatile storage for computer-readable instructions, data structures, program modules, and other data for the computer system 1200.

[0076]

[0087] The communication subsystem 1224 provides interfaces to other computer systems and networks. The communication subsystem 1224 functions as an interface for receiving data from other systems to computer system 1200 and for transmitting data from computer system 1200 to other systems. For example, the communication subsystem 1224 may enable computer system 1200 to connect to one or more devices via the Internet. In some embodiments, the communication subsystem 1224 may include radio frequency (RF) transceiver components for accessing wireless voice and / or data networks (e.g., using cellular telephone technology, 3G, 4G, or advanced data network technologies such as EDGE (Global Evolutionary High Speed ​​Data Rate), WiFi (IEEE 802.12 family standards), or other mobile communication technologies, or any combination thereof), a Global Positioning System (GPS) receiver component, and / or other components. In some embodiments, the communication subsystem 1224 may provide wired network connectivity (e.g., Ethernet) in addition to or instead of the wireless interface.

[0077]

[0088] In some embodiments, the communication subsystem 1224 may also receive input communications in the form of structured and / or unstructured data feeds 1226, event streams 1228, event updates 1230, etc., for one or more users who may use the computer system 1200.

[0078]

[0089] As an example, the communication subsystem 1224 may be configured to receive data feeds 1226 in real time from users of social networks and / or other communication services, such as web feeds including Twitter® feeds, Facebook® updates, Rich Site Summary (RSS) feeds, and / or real-time updates from one or more third-party information sources.

[0079]

[0090] Furthermore, the communication subsystem 1224 may also be configured to receive data in the form of a continuous data stream. This data may include an event stream 1228 of real-time events and / or event updates 1230, which may be continuous or unlimited in nature and have no 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, and automotive traffic monitoring.

[0080]

[0091] The communication subsystem 1224 may also be configured to output structured and / or unstructured data feeds 1226, event streams 1228, event updates 1230, etc., to one or more databases that can communicate with one or more streaming data source computers connected to the computer system 1200.

[0081]

[0092] The computer system 1200 may be one of various types, including handheld portable devices (e.g., iPhone® cellular phone, iPad® computing tablet, PDA), wearable devices (e.g., Google Glass® head-mounted display), PCs, workstations, mainframes, kiosks, server racks, or any other data processing systems.

[0082]

[0093] Due to the ever-changing nature of computers and networks, the description of the computer system 1200 shown in the figure is intended merely as a specific example. Many other configurations are possible, having more or fewer components than the system shown in the figure. For example, customized hardware may also be used, and / or certain 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 employed. Based on the disclosures and teachings provided herein, other ways and / or methods for implementing various embodiments should be apparent.

[0083]

[0094] As used herein, the terms “about,” “approximately,” and “substantially” should be interpreted as being within the range expected by those skilled in the art in light of this specification.

[0084]

[0095] The above description includes numerous details to facilitate a complete understanding of the various embodiments for illustrative purposes. However, it will be apparent that some embodiments can be carried out without some of these specific details. In other examples, well-known structures and devices are shown in the form of block diagrams.

[0085]

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

[0086]

[0097] Specific details are provided in the above description to facilitate a full understanding of the embodiments. However, it will be understood that embodiments can be carried out even without these specific details. For example, circuits, systems, networks, processes, and other components may be shown as components in the form of block diagrams to avoid obscuring the embodiments with unnecessary details. In other examples, well-known circuits, processes, algorithms, structures, and techniques may be shown without unnecessary details to avoid obscuring the embodiments.

[0087]

[0098] Furthermore, note that individual embodiments have been described as processes, shown as flowcharts, flow diagrams, data flow diagrams, structural diagrams, or block diagrams. While flowcharts sometimes describe processes as sequential, many processes can be executed in parallel or simultaneously. Moreover, the order of processes may be rearranged. A process terminates when a process is completed, but it may have additional steps not shown in the diagram. A process can correspond to a method, function, procedure, subroutine, subprogram, etc. If a process corresponds to a function, its termination may correspond to the function's return to the calling function or main function.

[0088]

[0099] The term “computer-readable medium” includes, but is not limited to, portable or fixed-storage devices, optical storage devices, wireless channels, and various other media capable of storing, containing, or carrying instructions and / or data. A code segment or machine-executable instruction may represent any combination of a procedure, function, subprogram, program, routine, subroutine, module, software package, class, or instruction, data structure, or program statement. A code segment may be connected to another code segment or hardware circuit by passing information, data, arguments, parameters, or memory contents. Information, arguments, parameters, data, etc., may be passed, transferred, or transmitted via any suitable means, including memory sharing, message passing, token passing, network transmission, etc.

[0089]

[0100] Furthermore, the embodiments may be implemented by hardware, software, firmware, middleware, microcode, a hardware description language, or any combination thereof. If implemented by software, firmware, middleware, or microcode, the program code or code segments for performing the required tasks may be stored in a machine-readable medium. A processor(s) may perform the required tasks.

[0090]

[0101] While the features are described in the above specification with reference to specific embodiments, it should be recognized that not all embodiments are limited thereto. Various features and aspects of several embodiments may be used individually or collectively. Furthermore, embodiments may be used in any number of environments and applications other than those described herein without departing from the broader spirit and scope of this specification. Therefore, this specification and the drawings should be considered illustrative, not limiting.

[0091]

[0102] Furthermore, for explanatory purposes, the method has been described in a specific order. In alternative embodiments, it should be understood that the method may be executed in an order different from that described. Also, it should be understood that the method described above may be executed by hardware components or embodied in a sequence of machine-executable instructions, which may be used to cause a machine, such as a general-purpose or special-purpose processor or a logic circuit programmed with instructions, to execute the method. These machine-executable instructions may be stored on one or more machine-readable media, such as a CD-ROM or other type of optical disk, a floppy diskette, ROM, RAM, EPROM, EEPROM, magnetic or optical card, flash memory, or other type of machine-readable media suitable for storing electronic instructions. Alternatively, the method may be executed by a combination of hardware and software.

Claims

1. A method for performing a polishing process on a substrate, Receiving a substrate in a known alignment within a carrier head of a polishing station for a polishing process, wherein the polishing process causes the substrate in the carrier head to be polished by a polishing pad on the platen such that the substrate passes over one or more sensors in the platen along one or more predetermined sensor paths for the substrate to the known alignment of the substrate; Moving the carrier head to the first position based on the one or more predetermined sensor paths, Moving the platen to a second position based on the one or more predetermined sensor paths, Rotating the substrate relative to the platen so that the one or more sensors pass along the one or more predetermined sensor paths. Methods that include...

2. The method according to claim 1, wherein one or more sensors are used to detect one or more attributes indicating the thickness of the substrate during polishing.

3. Based on the one or more predetermined sensor paths, a first rotational speed related to the platen is determined, Based on the one or more predetermined sensor paths, a second rotational speed related to the substrate is determined. The method according to claim 1, further comprising:

4. The method according to claim 1, wherein the groove of the polishing pad is offset from the corresponding axis of the platen.

5. The method according to claim 1, wherein the one or more sensors include at least one of an optical sensor or an electrical sensor.

6. The method according to claim 1, wherein each of the one or more sensor paths is associated with the corresponding sensor of each of the one or more sensors.

7. The method according to claim 1, wherein each of the one or more sensors shares at least one of the one or more sensor paths.

8. The method according to claim 7, wherein the one or more sensors pass along at least one of the one or more sensor paths at different times.

9. The method according to claim 1, wherein the one or more sensor paths maximize the signal quality associated with one or more of the one or more sensors.

10. The method according to claim 9, wherein maximizing the signal quality is determined by the one or more sensor paths that cross the center of the maximum number of dies.

11. The method according to claim 9, wherein maximizing the signal quality is determined by the one or more sensor paths that cross a maximum number of substantially vertical boundaries between dies.

12. A system for polishing circuit boards, A carrier head configured to accept a substrate, Platen and, One or more processors, One or more non-temporary computer-readable media containing instructions, wherein, when the instructions are executed by the one or more processors, the system... Receiving the substrate in a known alignment of the carrier head of a polishing system for a polishing process, wherein the polishing process is performed such that the substrate in the carrier head is polished by a polishing pad on the platen such that the substrate passes over one or more sensors in the platen along one or more predetermined sensor paths for the substrate to the known alignment of the substrate; Moving the carrier head to the first position based on the one or more predetermined sensor paths, Moving the platen to a second position based on the one or more predetermined sensor paths, Rotating the substrate relative to the platen so that the one or more sensors pass along the one or more predetermined sensor paths. One or more non-temporary computer-readable media that cause this to be done A system that includes these features.

13. The system according to claim 12, wherein the grooves of the polishing pad are offset from the corresponding axis of the platen.

14. The system according to claim 12, wherein the one or more sensors include at least one of a photodetector or an electrical detector.

15. The system according to claim 12, wherein each of the one or more sensor paths is associated with the corresponding sensor of each of the one or more sensors.

16. The system according to claim 12, wherein each of the one or more sensors shares at least one of the one or more sensor paths.

17. One or more non-temporary computer-readable media containing instructions, wherein, when the instructions are executed by one or more processors, the instructions are transmitted to the one or more processors. Receiving a substrate in a known alignment within a carrier head of a polishing station for a polishing process, wherein the polishing process causes the substrate in the carrier head to be polished by a polishing pad on the platen such that the substrate passes over one or more sensors in the platen along one or more predetermined sensor paths for the substrate to the known alignment of the substrate; Moving the carrier head to the first position based on the one or more predetermined sensor paths, Moving the platen to a second position based on the one or more predetermined sensor paths, Rotating the substrate relative to the platen so that the one or more sensors pass along the one or more predetermined sensor paths. One or more non-temporary computer-readable media that perform the steps necessary to carry out the process.

18. The one or more non-temporary computer-readable media according to claim 17, wherein the one or more sensor paths maximize the signal quality associated with one or more of the one or more sensors.

19. One or more non-temporary computer-readable media according to claim 18, wherein maximizing the signal quality is determined by one or more sensor paths that cross the center of the maximum number of dies.

20. One or more non-transient computer-readable media according to claim 18, wherein maximizing the signal quality is determined by one or more sensor paths that cross a maximum number of substantially vertical boundaries between dies.

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