Semiconductor chip test system and method

[0015] In the following description, several specific details are set forth. However, embodiments as described herein may be practiced without some of the specific details. In particular embodiments, well-known structures and techniques have not been shown in detail in order not to obscure the understanding of the description.

[0016] figure 1 A block diagram of a semiconductor chip testing system 10 according to one embodiment of the present invention is shown. The semiconductor chip test system 10 includes a robot arm 11 , a test interface device 12 , a test circuit 13 , an image acquisition device 14 , a processor 15 and a controller 16 .

[0017] The robotic arm 11 is used to pick up a semiconductor chip to be tested, such as a wafer to be tested or a packaged die, and place the semiconductor chip in the test interface device 12 or remove it from the test interface device 12 . In some cases, the robot arm 11 may be omitted from the semiconductor chip testing system 10 . For example, the semiconductor chip to be tested can be placed in the test interface device by a worker.

[0018] A test interface device 12 , such as a probe card for wafer testing, includes a plurality of probes for providing an electrical connection between the semiconductor chip to be tested and the test circuit 13 . The robot arm 11 inserts the semiconductor chip to be tested into the test interface device 12, especially into the corresponding chip test socket, so that the pins of the chip are in contact with the corresponding probes, so as to test the chip. The test interface device 12 preferably includes a plurality of chip test sockets to test a plurality of semiconductor chips. It is also conceivable that only one chip test socket is included in the test interface device 12 .

[0019] The test circuit 13 includes various circuits that provide semiconductor chip test functions. It is capable of performing various tests on the semiconductor chip under the control of the controller 16 .

[0020] Image acquisition device 14 is capable of acquiring an image of test interface device 12 showing a plurality of probes included by the test interface device. The image may refer to one or more images. In one embodiment, the image acquisition device 14 includes an imaging device, such as a camera, capable of acquiring images of the test interface device 12 . Preferably, only one image of the test interface device is acquired, which image shows all probes comprised by the test interface device. In one embodiment, a plurality of images of the test interface device 12 are acquired, each image showing at least a portion of the plurality of probes included in the test interface device 12 . Typically, a microscope camera is used due to the small size of the probes in test interface devices. Considering the field of view of the camera, it is sometimes necessary to image different parts of the test interface device separately, thus it is necessary to collect multiple images of the test interface device for a comprehensive inspection of the test interface device. In one embodiment, the image acquisition device 14 is capable of determining an image showing a plurality of probes of the test interface device based on the plurality of images, and in particular is able to combine the plurality of images to obtain an image of the test interface device showing all probes An image of , enabling this combination of images based on fiducial markers.

[0021] In another embodiment, the image acquisition device 14 can acquire one or more images from the external test interface device 12, for example, a camera can be installed somewhere outside the test system 10, and the image acquisition device of the test system 10 14 Receive one or more images from the camera either by wire or wirelessly.

[0022] During the semiconductor chip testing process, due to long-term use, the test interface device 12 may have defects, such as foreign objects, probe denting, probe tilt, and some probes are burnt black due to a short circuit in the test interface device. Certain defects may not affect semiconductor chip testing, in which case the test interface device can continue to be used. However, some defects may seriously affect the testing of semiconductor chips, and such test interface devices need to be replaced for further testing, so as to determine whether they really have fatal defects. A test interface device 12 containing these defects can be shown in the image of the test interface device taken above. By processing the image, defects in the test interface device can be identified, and it can be judged whether these defects may be fatal, thereby judging whether the test interface device needs to be replaced for further inspection.

[0023] Processor 15 receives the image of test interface device 12 from image acquisition device 14 and processes the image. Although the combining of multiple images into an image showing all probes of the test interface device is described with reference to the image acquisition device 14 , it is also contemplated that this process is performed in the processor 15 . In this case, the processor 15 receives a plurality of images from the image acquisition device 14, each image showing at least a portion of the probes of the test interface device, preferably each image showing different probes from each other. Processor 15 preferably includes an image combining unit (not shown) capable of combining multiple images of test interface device 12 to generate a combined image showing all probes of test interface device 12 . Processor 15 performs further processing on the combined image as described below to detect the test interface device. It is also contemplated that rather than combining multiple images together, each image is processed sequentially to determine possible defects in the portion of the test interface device shown in the current image.

[0024] The processor 15 processes the acquired images to inspect the test interface device 12 and determine possible defects in the test interface device 12 . Specifically, the processor 15 can extract a plurality of target regions from the current image based on the pixel value of the image, for a grayscale image, a grayscale value, and a predetermined first pixel threshold, and for each target region, based on Data representing the pixel value, size and/or location of the target area is used to determine possible defects in the test interface device shown in the current image. Pixel values ​​are described below with reference to grayscale values. It is also contemplated that the image of the test interface device 12 is a color image, and that color images are processed. In the case of processing color images, the respective thresholds as described below need to be adjusted appropriately.

[0025] In one embodiment, the processor 15 determines the number of possible defects in the test interface device 12 based on the image of the test interface device 12. In another embodiment, the processor 15 determines the number of defects in the test interface device 12 based on the image. The position of the defective probe. It is also contemplated to determine the type of defect.

[0026]The processor 15 can further generate an output signal based on the defect determination results for the test interface device 12 . Specifically, the processor 15 can compare the defect determination result of the test interface device 12 with a predetermined standard, and generate an output signal based on the comparison result. By comparing the defect determination results with predetermined standards, an output signal is automatically generated, enabling the user to be notified of the "health" of the test interface device during semiconductor chip testing, for example, the output signal may indicate that the user needs to replace the test interface device for further processing. It is also possible to show the user only the current defect determination results.

[0027] The predetermined criteria may include a predetermined number threshold, whereby the number of determined defects is compared with the predetermined number threshold, and when the number of determined defects is greater than the predetermined number threshold, it indicates that the test interface device has There are more than expected number of defects that need to be replaced for further inspection, thereby generating an output signal indicating that the test interface device 12 needs to be replaced. In this embodiment, by determining the number of possible defects in the test interface device, it is judged whether the test interface device can be used continuously or needs to be removed for special inspection.

[0028] The predetermined standard may include a pre-stored list, which at least includes the positions of key probes used in the testing process of the semiconductor chip to be tested. Probes that play a key role in a test. If the position of the probes involved in the defect overlaps with the positions of these key probes, the defect will affect subsequent testing, so the test interface device needs to be replaced. The processor 15 compares the determined positions of the probes involved in the defect with the positions of the key probes included in the pre-stored list, and compares the determined positions of the probes involved in the defect with the positions of the probes involved in the current test in the pre-stored list. The same condition indicates that the critical probes used for the current test may be defective, whereby an output signal is generated indicating that the test interface device needs to be replaced. .

[0029] In other embodiments, it is also conceivable that the predetermined criteria comprise pre-stored defect types, on the basis of which it can be determined whether to generate an output signal indicating that the test interface device needs to be replaced. It is also possible to include the type of defect in the aforementioned pre-stored list, and determine whether the test interface device needs to be replaced in combination with the type and location of the defect. The predetermined criteria can be expected to relate to any combination of defect type, location and number, and based on which it is determined whether the test interface device needs to be replaced.

[0030] The controller 16 controls the mechanical arm 11 , the test interface device 12 , the test circuit 13 , the image acquisition device 14 and the processor 15 so that they realize their respective functions according to predetermined timing.

[0031] figure 2 A block diagram of a processor 15 according to one embodiment of the invention is shown. The processor 15 includes an image preprocessing unit 151 , an area extraction unit 152 , a foreign matter determination unit 153 , a probe defect determination unit 154 , a recording unit 155 , and a determination result processing unit 156 .

[0032] The image preprocessing unit 151 receives the image of the test interface device 12 . The image preprocessing unit 151 can include the aforementioned image combination unit, which combines multiple images showing various parts of the test interface device 12 into one image showing all the probes thereof. In addition, the image preprocessing unit 151 can extract the image of the region of interest in the image of the test interface device 12, such as the image representing the area of ​​the chip test seat; and perform image binarization, contrast enhancement and/or image smoothing and other processing.

[0033] The preprocessed image of the test interface device 12 is output to the area extraction unit 152 . In the region extracting unit 152, the pixel value (gray value) of the image of the test interface device is compared with a predetermined first pixel threshold to extract a plurality of target regions from the current image. Preferably, the average pixel value of the current image can be determined first, and the first pixel threshold is determined based on the average pixel value of the current image. Considering that probes and/or foreign objects in the test interface device are lighter in color relative to the substrate, this first pixel threshold is set, and areas in the image are accounted for if their pixel values ​​are greater than this first pixel threshold Probes and/or foreign objects may be shown, and these areas are identified as target areas. The extracted object regions are then processed sequentially or in parallel. In one embodiment, the first pixel threshold may be a threshold range.

[0034] The foreign matter determination unit 153 receives the extracted multiple target areas, and determines for each target area whether it shows a foreign matter, and the determination of the foreign matter may be based on at least one of the size and pixel value of the target area. Specifically, determine the first data representing the size of the target area and/or the second data representing the pixel value of the target area, compare the first data with a predetermined size threshold, and/or compare the second data The data is compared with a predetermined second pixel value threshold to determine whether the target area represents a foreign object or a probe, and the target area representing the probe is determined as the first target area.

[0035] Typically foreign objects in test interface devices are much larger in size than the probe tips and are darker in color. Therefore, it can be determined whether the target area is a foreign object or not by the size and/or pixel value of the target area. A target area having a size larger than a predetermined size threshold and/or a pixel value smaller than a second pixel value threshold will be identified as representing a foreign object. The aforementioned size threshold and the second pixel value threshold should be set to be able to distinguish the probe from the foreign matter. In one embodiment, the size threshold can be set based on whether the currently processed image is the aforementioned combined image. When combining image mosaics showing parts of different probes, it may result in overlap between probes at the mosaic, so the size threshold should be set to be greater than or equal to the size of two normal probes. The second pixel value threshold should be greater than the first pixel value threshold and can be determined based on the pixel values ​​representing the region of the probe. Preferably, the second pixel threshold is determined to be smaller than a predetermined value of pixel values ​​of the intact probe region. This is because the probe may be dented or burned, making it darker in color. Dented or burnt probes are usually darker than sound probes, but not as dark as foreign objects. Setting the second pixel threshold in this way can avoid determining the sunken or burnt probe area as a foreign object. The second pixel value threshold may also be a threshold range.

[0036] The first data representing the size of the target area may be the area of ​​the target area, the area and/or diameter of the smallest circumscribed circle, or even the number of pixels in the target area. This is not limiting, and other parameters are contemplated as long as they represent the size of the target area. The second data representing the pixel values ​​of the target area may be the average value of the pixel values ​​of the pixels in the target area, which is not limiting.

[0037] In one embodiment, the above-described region extraction process and foreign matter determination process can be combined, in which case the pixel values ​​of the image can be compared to a predetermined threshold range that can distinguish foreign matter from the substrate and Probes (including burnt, pitted and sound probes) are distinguished and can be determined in conjunction with the first pixel value threshold and the second pixel value threshold. When some pixel values ​​are within this threshold range, it indicates that it may indicate a foreign object. When some pixel values ​​are less than this threshold range, these pixel values ​​indicate the substrate of the test interface device. When some pixel values ​​are greater than this threshold range, it indicates that these pixel values ​​represent the substrate of the test interface device. , it indicates that these pixel values ​​represent probes. The foreign matter can also be further determined in combination with the size of the regions formed by the pixel values ​​within the threshold range.

[0038] The probe defect determining unit 154 further performs defect detection on the probe on the first target region representing the probe. Defects on the probes mainly relate to whether the probes are burnt, whether the probes are dented, and whether the probes are tilted. The probe defect determination unit 154 performs detection of the above defects based on the color of each first target area and the distance between adjacent first target areas.

[0039] The probe defect determination unit 154 can compare the second data representing the pixel value of the first target area with a predetermined third pixel value threshold to identify whether there is a probe representing burnt or dented in the first target area. The third pixel value threshold is greater than the second pixel value threshold and can be determined based on the pixel values ​​of the sound probes. In one embodiment, the third pixel value threshold may be a threshold range representing a range of pixel values ​​for intact probes. Since the second data representing the pixel values ​​of the target area has been determined and the first target area is included in the plurality of target areas, the second data representing the pixel values ​​of the first target area can be obtained. If the pixel value of the first target area is greater than the third pixel value threshold or meets the third pixel value threshold range, it means that the first target area is a good probe; otherwise, it means that the probe represented by the first target area has been detected. Burnt or dented. Likewise, the second pixel value threshold and the third pixel value threshold can be combined to form a threshold range to distinguish intact probes, burnt or dented probes, and foreign objects.

[0040] The probe defect determination unit 154 can also determine third data representing the distance between the first target area and another adjacent first target area, and compare the third data with a predetermined distance threshold to identify Indicates the first target region of the tilted probe. When a certain probe is tilted, the distance between two adjacent probes will change and become too large or too small, and the distance threshold can be determined based on the distance between the intact probes. The distance threshold is preferably Threshold range representing the distance between intact probes. When the determined distance between the first target regions is within the threshold range, it means that the probe tilt is not involved; otherwise, it is determined that the probe tilt is involved. In one embodiment, in the case of judging that the probes are tilted between certain two probes, it can be further determined which probe is tilted in combination with the position of the original probes in the current test interface device. Since the minimum goal of image processing according to various embodiments of the present invention is to pre-judge the "health status" of the test interface device during chip testing, it is also possible not to specifically limit which probe is tilted, but only to record The current two probes may involve tip tilt. This can improve the processing speed and meet the test time requirements. A detailed inspection can be performed after the test interface device is removed.

[0041] The probe defect determination unit 154 can first determine for each first target region whether it is inclined, and then determine whether it is burnt or dented, and vice versa. When the probe tilt is first determined, it is not necessary to determine whether it is burnt or dented, and only the first target area that does not involve probe tilt is further inspected. Therefore, it is possible to determine the first target area that does not involve probe inclination as a new first target area, and then further detect whether the probe is burnt or dented for the new first target area. The same is true when the probes are first determined to be burnt or dented.

[0042] The recording unit 155 records the defects that may exist in the probe interface device determined by the above-mentioned foreign matter determining unit 153 and the probe defect determining unit 154 , especially records the position, type and/or quantity of the defects. Where multiple images of a probe interface device are processed sequentially showing different probes from each other, the defect shown in each image is recorded and the defects in the multiple images are added together to determine the probe Possible defects in pin interface devices.

[0043] The determination result processing unit 156 compares the recorded defect determination result with a predetermined standard, and generates an output signal based on the comparison result. The output signal can be output by the test system to the user to prompt the user to replace the test interface device. The output signal can be a visual signal or an audible signal.

[0044] above reference figure 1 The image acquisition device, processor, and controller shown in are showing a semiconductor chip test system according to an embodiment of the present invention, and it can be expected that all or part of the functions of the image acquisition device, processor, and controller are combined in a single computer and /or implemented in the processor. It is contemplated that the processor is located at a remote location. In one embodiment, the image acquisition device includes an imaging device that captures images of the test interface device and sends the captured images to a processor at a remote location that sends determinations of defects back to a computer at the test system. A controller enables corresponding output signals to be generated at the test system.

[0045] image 3 A method 30 for testing a semiconductor chip using a semiconductor chip testing system according to an embodiment of the present invention is shown.

[0046] According to the method 30, at 100, an image of a test interface device is acquired, the image showing a plurality of probes of the test interface device. At 200, an image of the test interface device is processed and the test interface device is inspected based on the image to determine possible defects in the test interface device, in particular to determine the number of defects, the location of the probes involved in the defect and/or the location of the defect. type. At 300, an output signal is generated based on the determination of the defect.

[0047] In the process of testing a semiconductor chip using a semiconductor chip testing system, the image of the test interface device is acquired, thereby adding the above method 30, so that the "health status" of the test interface device can be determined in real time during the semiconductor chip test process, so as to determine whether The test interface device needs to be removed from the test system for further inspection.

[0048] In one embodiment, at 300, the determination of the defect is compared to a predetermined standard to generate an output signal. The predetermined criteria may include a predetermined number threshold, in which case, at 200, the number of defects that may exist in the test interface device is determined, and the number is compared with the predetermined number threshold, and when it is determined that the number is greater than An output signal is generated indicating that the test interface device needs to be replaced if the quantity threshold is exceeded.

[0049] The predetermined criteria may include a pre-stored list including at least the locations of key probes for testing the semiconductor chip to be tested. In this case, at 200, the location of the probe involved in the defect in the test interface device is determined, and the location is compared to a pre-stored list, upon determining that the location is the same as the location in the pre-stored list An output signal is generated indicating that the test interface device needs to be replaced in the event of a .

[0050] In order to detect possible defects in the test interface device, at 200, image processing is performed on the image of the test interface device. In one embodiment, a plurality of target regions are extracted from the image based on pixel values ​​of the image and a predetermined first pixel threshold, the target regions representing foreign objects and/or probes, for each target region based on the representation of the The pixel value, size and/or position data of the target area is used to determine possible defects in the test interface device shown in this image.

[0051] Specifically, extract a plurality of target areas from the image based on the pixel values ​​of the image and a predetermined first pixel threshold; for each target area, determine the first data representing the size of the target area and/or represent the target area The first data and/or the second data are compared with the predetermined size threshold and/or the second pixel value threshold, respectively, to determine whether the target area represents a foreign object or a probe, and will represent a probe The target area of ​​the needle is determined as the first target area.

[0052] Next, for each first target area, determine third data representing the distance between the first target area and another adjacent first target area, and compare the third data with a predetermined distance threshold , to determine whether the first target region represents a tilted probe, the first target region other than the first target region representing a tilted probe is the first target region of a non-sloping probe, which will represent a non-sloping The first target area of ​​the probe is determined as the new first target area.

[0053] Next, for each new first target region, the second data representing the pixel value of the first target region is compared with a predetermined third pixel value threshold to identify the first pixel representing a burnt or dented probe. a target area. It is also contemplated to first determine for each first target area whether it is burnt or dented, and then determine the tilt of the corresponding probe for first target areas that are not burned or dented.

[0054] It is contemplated that after processing for each target area in 200, all defects that may exist in the test interface device are determined. At 300, the determination results of each defect among all the defect determination results are respectively compared with a predetermined standard, and an output signal is generated based on the comparison result. For example, at 200 the number of all defects is determined, and at 300 the number is compared with a predetermined standard.

[0055] It is also conceivable that, after a defect is determined for a target area in 200, the determination result of the defect is compared with a predetermined standard at 300, thereby generating an output signal based on the comparison result. For example, immediately after determining at 200 the location of a target area where a defect exists and/or the type of defect present, the location and/or type are compared at 300 to predetermined criteria.

[0056] Figure 4 A flow 200 of processing an image of a test interface device according to an embodiment of the present invention is shown. The process 200 can be implemented by the processor 15 .

[0057] According to this embodiment, at 201, one or more images of the test interface device from the image acquisition device are pre-processed, which includes combining multiple images showing different parts of the test interface device from each other into an image of the test interface device. an image. This combination of images can be based, for example, on fiducial markers shown in the images. Sequential processing of each of the multiple images showing different portions is also contemplated. In one embodiment, the above preprocessing further includes performing image enhancement, segmentation and/or binarization.

[0058] At 202, compare the pixel values ​​of the preprocessed image with a predetermined first pixel threshold to extract multiple target regions. Since probes and/or foreign objects in the test interface device are lighter in color compared to the substrate, this first pixel threshold is set, and areas in the image that have pixel values ​​greater than the first pixel threshold indicate that these areas may Probes and/or foreign objects are shown, these areas are determined as target areas, and all target areas are stored, otherwise the pixel values ​​in the image represent the substrate of the test interface device.

[0059] At 203, a target area counter i is set and assigned a value of 1. At 204, the i-th target region is extracted.

[0060] At 205, first data representing the size of the target area and/or second data representing pixel values ​​of the target area are determined, the first data is compared with a predetermined size threshold, and/or the second The data is compared to a predetermined second pixel value threshold to determine whether the target area represents a foreign object or a probe. Typically foreign objects in test interface devices are much larger in size than the probe tips and are darker in color. Therefore, it can be determined whether the target area is a foreign object or not by the size and/or pixel value of the target area. It is contemplated that the target area is determined to represent a foreign object only when it is determined that the first data is greater than the size threshold or the second data is smaller than the second pixel threshold, and it is also contemplated that only when the first data is determined to be greater than the size threshold and the second data is smaller than the second pixel threshold Only when the pixel threshold is reached, it is determined that the target area represents a foreign object.

[0061] If it is determined at 205 that the first data is greater than the size threshold and/or the second data is less than the second pixel threshold, then at 206 the target area is determined to represent a foreign object, and at 214 the defect is recorded, particularly the location of the foreign object and the type of defect ( foreign body). In one embodiment, a defect counter can be set at 214, and the defect counter is incremented by 1 each time a defect is detected, thereby determining the number of defects. After recording the defect, make the target area counter i=i+1, determine whether all target areas in the image have been processed by comparing i with the number of target areas in the image at 215, if not, return to 204. Continue to extract the i-th target area for subsequent processing.

[0062] If it is determined at 205 that the first data is less than the size threshold and/or the second data is greater than the second pixel threshold, then at 207 the target area is determined to represent the first target area of ​​the probe.

[0063] At 208, third data representing a distance between the first target area and another adjacent first target area is determined and compared to a predetermined distance threshold to identify probes indicative of tilt the first target area. The distance threshold may be a threshold range.

[0064] If it is determined at 208 that the third data is not within the distance threshold range, that is, the distance between two regions representing probes is much larger or smaller than the normal distance between probes, it indicates that there may be a probe tilt. Thus, at 209 it is determined that the first target area may involve probe tilt, at 214 the defect involving probe tilt is recorded, after recording the defect, make target area counter i=i+1, and proceed to 215 .

[0065] If it is determined at 208 that the third data is within the distance threshold, that is, the distance between the two regions representing the probes meets the normal distance between the probes, at 210 it is determined that the first target region does not involve the probe. The needle is tilted.

[0066] The second data representing the pixel values ​​of the first target area is further compared at 211 to a predetermined third pixel value threshold to identify the first target area representing a burnt or dented probe.

[0067] If it is determined at 211 that the second data is less than the third pixel threshold, and the third pixel threshold is greater than the second pixel threshold, then at 212 it is determined that the probe represented by the first target area is burnt or dented, and thus, at 214, the Defect, and advance to 215 with target region counter i=i+1.

[0068] If it is determined at 211 that the second data is greater than the third pixel threshold, then at 213 the first target area is determined to represent a good probe, directly setting the target area counter i=i+1, and proceeding to 215 .

[0069] In 215, it is determined whether all target regions in the image have been processed by comparing i with the number of target regions in the image, if it is determined that all target regions have been processed, then proceed to 216, and the The determination results of all defects are compared with a predetermined standard, and an output signal is generated based on the comparison result.

[0070] The above is only for reference Figure 3-4 The illustrated embodiments describe the method of the present invention, and it will be understood that the various processes included in the above embodiments are not limiting and may be deleted, combined, altered, split and/or recombined as required to Add/modify/delete corresponding functions. For example, in one embodiment, processing related to probe defect detection can be eliminated and only foreign object detection is performed; it is also contemplated that only one or more of the above defect detection is performed. While described with reference to defects such as foreign matter, probe denting, probe burnt due to short circuit, probe tilt, etc., it is also contemplated that the processor processes the image of the test interface device to detect other defects.

[0071] Although in Figure 4 While each target region is shown to be processed sequentially, it is also contemplated to perform the above processing in parallel for each target region. Also, while in Figure 4 It is shown that after defect detection is performed for all target areas, the defect determination results are compared with predetermined standards. It is also expected that at 214, the defect determination results for each target area are compared with predetermined standards. Then end the defect detection of the remaining target areas, and directly generate an output signal based on the comparison result, if not, make the target area counter i=i+1, proceed to 204, and extract the next target area. In this example, Figure 4 The illustrated processing at 215 and 216 can be omitted.

[0072]In various embodiments of the present invention, reference is made to a number of thresholds, including quantity thresholds, size thresholds, first, second and third pixel value thresholds, and distance thresholds, contemplated for different types of test interface devices and /or detect the environment, and adjust the size or range of the above thresholds to meet the needs of specific application objects and/or environments. The predetermined standard is also mentioned in the above embodiments, and it can be expected to set the predetermined standard for different types of test interfaces and different tests that need to be performed.

[0073] The apparatus and methods of the present invention are described above with reference to various embodiments, wherein the mentioned embodiments may include a particular feature, structure or characteristic, but not every embodiment necessarily includes the particular feature, structure or characteristic. Furthermore, some embodiments may have some or all of the features described for other embodiments or none of the features described for other embodiments.

[0074] As used in the claims, the use of the ordinal adjectives "first," "second," "third," etc. to describe common elements merely means that different instances of similar elements are being referred to, and is not intended to be used unless otherwise indicated. It is implied that elements so described must be in the order given, whether temporally, spatially, hierarchically or in any other manner.

[0075] Individual features of different embodiments or examples can be combined in various ways with some features included and others excluded to adapt to many different applications. The drawings and foregoing description give examples of embodiments. Those skilled in the art will appreciate that one or more of the described elements may be combined into a single functional element. Alternatively, certain elements may be divided into multiple functional elements. Elements from one embodiment may be added to another embodiment. For example, the order of the processes described herein may be changed and is not limited to the manner described herein. Furthermore, the acts of any flowchart need not be performed in the order presented; nor do all acts necessarily need to be performed. Furthermore, those acts that are not dependent on other acts can be performed in parallel with other acts. The scope of the embodiments is by no means limited by these specific examples. Numerous variations, such as differences in processing sequence, product composition and structure, are possible, whether explicitly given in the specification or not.