TW535473B - System and method for identifying solder joint defects - Google Patents

Abstract

An improved circuit inspection system (100) incorporates an automated measuring technique (1400) that accounts for acceptable Z-axis elevation variance across both a printed-circuit device (410) and a mounting surface (420) when making solder-joint pass/fail decisions. The improved solder-joint inspection system (100) applies a near neighbor solder joint diameter error analysis (1100) for each solder joint on a printed-circuit device (410). A near neighbor solder joint diameter error outlier analysis (1300) is used to identify solder joint defects with improved accuracy.

Description

535473 V. Description of the Invention The present disclosure is generally related to a system and method for inspecting the resolution of a circuit board assembly using a measurement system, and in particular to measuring solder joints in a circuit board assembly for quality analysis. system. BeiGong 1 Fast and accurate quality control inspection of welding and assembly of electronic devices has become a priority item in the electronics manufacturing industry. Q. The size of components and soldering connections has become smaller, components on circuit board assemblies have been improved. Put under the device package to avoid being seen = The advent of surface mounting technology (bribery) has made rapid and accurate inspection of electronic devices and electrical connections between devices extremely difficult in manufacturing environments. Many existing inspection systems for electronic devices and connections are used Penetrating the Korean radio to form an image, it emphasizes the appearance of these devices and connecting internal structures. These systems often use conventional x-ray photography, where penetrating radiography includes X-rays. For example, the chest, arms, feet, spine and other human bodies The medical treatment of the part is first possible, and it is the most familiar example of the usual X-ray radiographic images. When an object is formed by an X-ray beam, the image or picture formed by the X-ray beam presents the X-ray shadow shaped by the object being inspected. Light and shadow are recorded by X-ray sensitive materials such as negatives or other suitable facilities. The shape of X-rays or X-ray images is not only reflected by the internal structural features of the object The direction of the X-ray center hitting the object is determined. Therefore, a complete interpretation and analysis of X-ray images implemented by human vision or computer values is required. Some wisdom about the characteristics of the object and its orientation to the x-ray beam is needed ^ / 、、、 二 # It is necessary to make specific assumptions about the shape and internal structure of the object:… ^ The direction of the X-rays on the edge of the object. Based on these shapes of light ~ image, it can be analyzed to determine the corresponding object. Structure 4 535473 5. Inventive features, such as flaws in the solder connection, which produce various image appearances. These fakes. X warp creates blur, which degrades the reliability of image interpretation and the quality of decision-making based on X-ray image analysis The fundamental ambiguity due to the assumptions of conventional X-ray analysis is that small variations in solder connection defects such as structural characteristics of shape, density, and size are usually caused by the solder connection itself and nearby solder connections, electronic devices, circuit boards, and The shading blocks of other objects are obscured. Since the shading blocks and nearby objects are usually different for each type of solder, it is necessary to take a sufficient hypothetical history to fine stone Cui i also Determining the shape, size, and location of the solder within each solder joint is extremely tedious and often almost impossible. In an attempt to compensate for these deficiencies, some systems employ the ability to view objects from several angles. This additional Observation causes these systems to partly depend on the ambiguity presented in the X-ray projection image. However, the use of multiple viewing angles requires the use of complex mechanical manipulation systems. 'Usually requires up to five independent non-orthogonal motion axes. This mechanical complexity results in Increased cost, longer inspection time, size and weight, poor positioning accuracy due to mechanical complexity, and the complexity of calibration and computer control due to non-orthogonal motion axes. As usual with the discussion above 乂The problems related to photography can be alleviated by generating: = cross-sectional images of objects. For example, X-ray fracture assisted by tomography X-ray tomography (CT) # ^ Beer layer makeup technology has been used in medical applications To produce a section or tomographic image. It has been widely used in medical applications mainly due to approximately -or two public _〇 ·. … Wang You's relatively low resolution is satisfactory and is not as stringent as the corresponding industrial requirements. In the case of electronic inspection, special electrical materials such as solder joints are required in the house. V. Inspection of the invention description (3), for example, 20 micrometers (approximately 0.08 in._one. In addition, industrial == Multiple images must be produced per second for practical use in industrial production lines-an inspection system that first achieves the speed and accuracy required for electronic inspection is described in the following patent: issued to others: "Using US Patent No. 5,097,492, Γ 二 Γ, etc. for the automatic tomographic X-ray inspection of electronic inspection ^, "quoting the X-ray inspection system first", etc. The title is "Automation for Electronic Inspection: Japanese ^ Le US patent No. 5 plus ".. first", US patent No. 、, US patent No. 5,291,535 entitled "Used to detect excessive / insufficient material defects and clothing", issued to r〇 The title of "U.S. Patent for Detecting and Controlling Solder Property: U.S. Patent No. 5" & "Tiger Patent, Issued-Method and Apparatus for Checking Electrical Connections by Si 5 561" The patent of Jinjin No., issued to the deficiencies, etc. is entitled "Used for high-resolution = child inspection. Method and Device "U.S. Patent No. 54: U.S. Patent No. 5,259, to Baker et al. Entitled" Tomographic X-ray Examination System and :: Introduction: Method of Radiation Path Radiation Source "12 U.S. Patent No. 5,583,904 entitled "Continuous Linear Scanning Tomography X α-2 System and Method", U.S. Patent entitled "Self-Gamma and Curve Compensation for Tomography X-ray Board Inspection" issued to S Search The mother of the first ^, ..., patent is incorporated herein by reference. 535473 V. Description of the invention (4) In a tomography system, it observes a fixed system and has a smaller imaging area than the object being inspected , It may be necessary to move the object around

The volume is used to locate different areas of the object in the imaging area to generate a multi-slice X-ray examination, and the pieces together form an image of the entire object. This is often achieved by supporting the object with a mechanical manipulation system such as an X-Y-Z positioning table. This stage is moved to bring the desired area of the object into the imaging area. The movement in the X and Y directions determines the area to be inspected, and the movement in the z direction moves the object up and down to select the plane within the object whose cross-sectional image is to be taken. Several of the above-referenced patent disclosure devices and methods are used to generate cross-sectional images of a test object at a fixed or alternative cross-sectional image focus plane. In these systems, a x-light source system and a x-light detector system are isolated at a fixed distance in the z-axis direction and the sectional image focus plane is located at a pre-specified position in the z-axis direction. This position is for the X-ray system, the M-ray detector system, and the direction of the vehicle is in the middle. The x-ray detection and measurement system collects data. The planar image can thus be claimed by I to M to be fixed in the fixed or selectable sectional image focusing plane at a predetermined specific position along the z-axis direction. : And in these systems, it is important that the positions of the focal plane of the cross-sectional image and the plane within the object to be imaged are assembled to coincide with the same -position along the Z-axis direction. If this condition is not met, the selected objects in the test object will not be obtained. Instead, the cross-sectional image of the plane in the test object that includes the selected appearance π square ^ square test object will be in some configurations less than the optimal field of view for the material to join (V-one: 535473 five According to the invention, the imaging consequence is that these analyses that are less than the optimal field of view will lead to inaccurate analysis of related solder joints. At present, it is generally used by technical entities that are used to locate the selected appearance of the test object in the focus plane of the cross-sectional image. The z-axis position of the selected appearance is used. 3 measurements and 4 objects are positioned using this measurement so that the appearance of the appearance matches the z-axis position of the focal plane of the profile shirt. Any standard method and device can be used for the entity Measure the 2-axis position of the selected appearance. 2-axis measurement 1 systems are available in several types on the market, which are used to determine the test object on 1 or 4 surfaces that are known on z or just below the surface The distance between the appearances of the ^ type system simply mechanically fixes the test object, a mechanical probe: = laser optical triangulation system,-optical interferometer, and the z-axis position measurement system One can be used Forms a "z-map" of the surface of the test object. The "z-map" typically contains an array of χ_γ positions with a ζ value of the surface of the test object at a particular position. The position is on a plane shared with the test object. It is spotted on the top, which is substantially parallel to the shoulder surface to the focal plane of the image. The cross-sectional image appearance system 2 on the circuit board takes the money used as the m and uses the f-based range-finding cat. The device has been particularly used in cross-section x-ray imaging systems. It is used to form an electronic circuit board assembly. The circuit board assembly is typically thinner than the surface area where the component is being mounted. Some circuit assemblies It is made of a very stable material such as pottery. However, most of the electricity: Boards are slightly elastic or in some cases very structured. This elasticity allows the circuit board to be perpendicular to the main surface area (i.e. contains = 535473 V. Description of the invention The surface area of the pin) or the z-axis is wound. In addition, the thickness of some circuit board assemblies will vary. In addition to the electronic assembly, many other objects have dimensional variations in proportion. X-ray imaging The depth of field of view of the Z focusing plane is significant. By measuring the surface of the test object being wound, the variation in the Z dimension can be used to appropriately adjust the test object's z-focal plane for X-ray imaging of the section. The positional relationship allows the desired image of the appearance discussed in the test object to be imaged. This rangefinder standard is designed for use as described in US Patent No. 4,926,425 to Baker et al. Within the system, this patent is hereinafter referred to as the 452 patent. The 452 patent discloses a tomographic x-ray inspection system in which an M x-ray-based imaging system has a very shallow field of view and is used to check the solid state of a printed circuit board. Objects. The depth line of the field of view provides facilities for inspecting solder joints without disturbing the components above or below the solder joint. The material above or below the solder joint is out of focus and therefore has a roughly uniform background. To provide the desired selectivity, tomographic X-ray inspection results in: the system's field of view depth is less than about one millionth of an inch. Unfortunately, the surface variation of printed circuit boards often exceeds this tolerance. 2 To serve this disadvantage, the use of the surface of the printed circuit board-laser detector is not good, right. Laser rangefinder

The loyalty map of you 3 is used to image the X first to position the printed circuit board so that it is within one of the circuit board inspection systems even when the board is moved from the field of view to another. The disadvantage is that in deciding the solder joint to be measured, the method is reduced to indicating that a solder joint is "possible, defective". This Tan material joint inspection II, "or" There are 4 families of joints with a female appearance appearance application 9 535473 V. Description of the invention (7 preset thresholds to make these connections. Method & identify 4 defects "solder joint! Right What percentage of the individual solder joints of the array package are "defective" circuit circuits? The proportion is particularly clear. The circuit package of the "kickoff: matrix: A) of the solder joints of the purchase order has a flat surface, which is generally It is covered by a rectangular or regular body, and it is "Japanese film. This side may be led back and forth by a small ball? Christine:" or the integrated circuit of the integrated circuit package ... As is known, the flat bottom surface is formed-a substrate / a multilayer substrate on the mold) 'integrated circuit mold is fixed here. The combination of several factors makes the bonding of a matrix of materials to the solder ball three important two: the surface of the wheel (that is, the welding will be wound to form the package mounting surface) First, the relative distance between the surface of the packaging material and the printed circuit board y, or Ί Generally speaking, BGA „, makes its side drink the mounting surface of the road board (that is, the edges flip up). However, J 1 angle corner BGA package winding mainly occurs in various ways, and it is packaged with coffee. The distance between the mounting surface and the printed circuit board varies in many different ways across the entire mounting surface. Such as pillar array packages (CGA), flip-flops, chip size packages (csp), and quadrangular planar packages (QFp), but not Other packages limited to this also suffer from entanglement problems. "In addition to package entanglement, printed circuit board materials are also entangled. It should be 1%. This situation is not mutually exclusive. In another way, printed circuits The board (that is, the mounting surface) and the package can be entangled. In addition, the printed circuit and (or any of the m-any-will be subject to "tilt". When the height of the mounting surface Z dimension) on the package or printed circuit board Ren 10 from the upper side to the other five invention is described in (8) exhibits a change when the side.

These and other factors can—the effect of & A ^ ^, make the printed circuit assembly contain: several devices (such as array packaging), which have significant changes in the; measurement. In the case of a ball grid array where you " such as a badly connected surface conductor is substantially equal to (in the case of installation applied to BGA packages. Hopewell), the increase in the distance between the bga women's clothing surface and the printed circuit board will increase As a result, more than one solder joint is elongated, making the retro t solder joints. In general, the lighter the tn is in the pre-reflow condition, the closer it is to the center of the array, and its reflow condition collapses. Columns crash more often. m "Although the ball grid array near the outer edge of the array, the entire majority of the measured solder on the column package, the wide printed circuit assembly and the array package are related to the electrical or electrical via the corresponding solder. The joints are properly connected. The relevant differences in the various measurements of solder joints (in the case where the corresponding solder joints are properly connected) are acceptable for the entire number of solder joint measurements; representative of the affected variation. The wide range of solder joint measurement makes it extremely difficult to set the pass / fail gate value for various solder joint measurements that accurately reflect the true electrical and physical conditions of each material joint. In practice, it is necessary to use a dry material joint for a concrete device. It is problematic for the inspection system to accurately detect "open circuits". Not only is it time consuming to reproduce each BGA package, it is identified as having a < <, > defective solder joint test results, a full-featured test lacking a printed circuit (i.e., fully embedded printed circuit board) assembly, or In-circuit testing of components' requires 100% electrical testing. Non-destructive certification methods are not available. 535473 5. Description of the invention (9) The accuracy of the conclusion of the defect is independently confirmed. In response ', some manufacturers already have elliptical gaskets using various printed circuit devices. The oval-shaped pads cause the solder balls to form an oval solder joint when the pads are properly bonded by the solder. These ^ circle = cymbals allow detection of "open" solder joints while the associated solder image remains circular. Although there are other improvements in detecting solder joints, it wants to have improved systems and methods for improving solder joint inspection systems: precision; it is based on accurately identifying the PCBs used to physically and electrically connect printed circuit boards. Defective solder joints for various printed circuit devices that take into account acceptable variations in the printed circuit device being measured. In response to these and other deficiencies in the known art, a solder joint inspection system and method is used to apply test thresholds to solder joint defects. In one configuration, the material bonding inspection system records the position information of several pins (ie, solder bonding interface) on each printed circuit device of the circuit assembly (that is, a fully implanted printed circuit board) and the printed circuit. The distance between the mounting surface of the assembly and the device package is changed: failure: Tan, the material joint inspection system is generated for each-Tan material joint-expected to pass: = straight f to allow for the group itching on each printed circuit device Material junction = acceptable variation of recorded true value. Briefly describe, on-the-shelf ... an improved itchy material joint inspection system for measuring m-fluid use for solder joints; and a data storage facility is implemented. … Recorded in the printed circuit assembly for each “tank material connection measurement,” is: heart === is considered to be provided-a method for identification ... one by one 'This method can be encapsulated into the following steps: Welding 12 V. Description of the invention 10 Expected expected value of material bonding, which takes into account the variation in the height of the printed circuit device against the printed circuit board; a comparison is recorded for each material bonding = an error value is generated for each solder joint; As well as identifying out-of-bounds measurements, other embodiments of the system can be seen as providing a method for expanding the rigidity test threshold. In this regard, this method can be summarized into the following steps :: Obtaining position information for several pins on a printed circuit device; Obtaining information about the height variation of the entire mounting surface of the printed circuit device; 2 recordings Measurements of several solder joints related to the plurality of pins; response to = = height variation of the mounting surface to estimate the possible range of the respective solder joints = range; and setting at least one threshold value to respond to the range A boundary. Other systems, methods, and features related to the use of electrical connection defects that take into account acceptable solder joint diameter variations in printed circuit board assemblies will become apparent to those skilled in the art by reviewing the following figures and detailed description understandable. It is intended that all such systems, methods, and features included in this description be in the field of systems and methods for identifying defects that are protected by the scope of the attached patent application. The system and method for confirming the electrical connection defect can be better understood with reference to the following drawings. The components in the figure do not necessarily emphasize their scales, but they clearly emphasize the principle of the test method in confirming the electrical connection between more than one of the printed circuit boards. Furthermore, the same component number is designated as the corresponding part in each drawing. FIG. 1 is a block diagram of an exemplary circuit inspection system. Figure 2 is a description of the solder joint diameter value of an exemplary ball grid array. 535473 5. Description of the invention (n figure. Figure 3 is a drawing of the solder joint diameter value of another exemplary ball grid array. Brother Fig. 4 is a side view of the influence of the ball grid array and winding on the respective solder joint diameters. / Fig. 5 is the ball grid array winding and the printed circuit board tilt are consumed and the respective solder joint diameter is wound. Figure 6 is a plan view of an exemplary ball grid array device, showing the method used to determine the distance from the center of a device for two-material bonding. #Figure is solder bonding by the center of I Exemplary tracing diagram of diameter value to solder joint (pin) distance. A picture is the second exemplary tracing diagram of solder junction diameter value to solder joint (pin) distance from the center of mouth. Mouth ... The figure is an exaggerated plan view of the solder joint on the exemplary ball grid array package. One of the second configuration of solder joint on an exemplary ball grid array package. The solder joint diameter is an exaggerated plan view. The intention is to show the correlation between the identified solder joint and its adjacent solder joint on the -exemplary ball grid array package, which can be applied by the circuit inspection system of Fig. 1. f U is the proximity of the package type and error size classification. The tracing point diagram of the σ straight value error of the adjacent welding can be created by using the daily record of the circuit inspection system in Fig. 1. Figure 13 is a tracing point diagram showing the error of the joint diameter near the adjacent material. 14 5 、 Explanation of the invention (丨 2) '' External: Analysis '' can be used in the circuit inspection system shown in Figure 1.… The figure is a flowchart showing the method used to use the test threshold value. '' It can be used in the circuit inspection shown in Figure 1 The system is implemented. Figure 15 is a functional block diagram showing the exemplary components of the solder joint analysis application shown in Figure 丨. Figure 16 is-Process ® shows a method for identifying solder joint flaws, which The circuit inspection system of Fig. 1 can be implemented. The present invention is directed to a system and method for the problems listed above. It is particularly important that an improved solder joint inspection system is configured to apply the method for use in testing. Door swing value, which can significantly reduce the number of "defects" found during the analysis of more than one measurement for each material interface. Improvements that are assembled in accordance with the method used to test threshold values The solder joint inspection system takes into account the acceptable variation in the distance between the mounting surface of the printed circuit device and the printed circuit board when setting the pass / fail criteria. More specifically, Caimu uses the test gate method to identify High-frequency variation between adjacent solder joints accepts low-frequency variation of measured parameters of adjacent solder joints across the entire mounting surface of a printed circuit device. To facilitate the description of the sigma system and methods, an exemplary system reference The diagrams are discussed. The interpretation system and related methods are provided for illustrative purposes only. Various modifications are possible without departing from their inventive concepts. For example, the explanatory materials, diagrams, and related descriptions The focal point is a direct measurement related to solder bonding that is fixed to the BG A package. Those skilled in the art will understand that the low-frequency variation that occurs in other solder joint types (that is, non-spherical joints) is at least the same reason that caused the BGA package to circulate with the printed circuit board. 535473 5. Description of the invention. Eight—According to a preferred embodiment, if a commercially available circuit board inspection is performed by Aglolem Technology of Palo Alto, Calif. = 5DX x-ray inspection system available from the company, the system is recorded in the printed circuit assembly (ie, in printed circuit The board is implanted) on the position of several pins (ie solder joint interface). The solder joint inspection system uses this positional information to match each of the adjacent groups of pins on the printed electronics to each of the plurality of pins. After recording ㈣observed-at least-features of solder joints-actual measurements, the solder joint inspection system generates an IT failure / failure criterion for each measurement associated with each individual printed circuit board. It takes into account the acceptable (i.e. low frequency) variation of the actual measured i recorded. Exemplary solder joints can be measured thickness, shape, hill height, solder volume, and others. Several estimation techniques can be used to identify individualized expectations for each pin of the printed circuit board. For example, an embodiment uses statistics derived from adjacent solder joint measurements to estimate the desired measurement currently being tested. Statistics can include average, mean, median, and so on. In a variation of this first embodiment, measurements recorded from the entire mounting surface may be sampled when estimating the expected value. In other words, the value of each solder joint used to lightly close the 100-pin device can be determined from the actual measurement of the set of solder joints from the entire 100-pin device. -The second embodiment implements a two-dimensional polynomial fit to the measurement data for solder joint identification under test-the desired measurement value. -The third embodiment uses a FOU⑽ analysis of the measurement results to identify the high-frequency variation in the joining of adjacent bars. The inverse Fourler transform can be used to identify specific solder joints-Issue 16 535473 Description of the Invention Expected measurements. Once the relevant expected measurements for each solder joint of one of the packages under test are identified, the solder joint inspection system performs a comparison of the inter-period measurements of each of the special joints in question with the associated expected values to produce a difference. After the associated error values for the individual solder joints tested on each printed circuit device have been identified, out-of-bounds analysis can be performed to derive conventional pass / fail criteria for each solder joint.

Referring now to FIG. 1, shown is a functional block diagram showing various components within an exemplary solder joint inspection system 100. As shown in FIG. Generally speaking, Fig. 1 shows various functional building blocks of a computer-based solder joint inspection system, which can be applied with various methods for identifying and confirming solder joint defects A. The solder joint inspection system 1 〇〇 It can include any of a wide variety of wired and / or wireless computing devices, such as desktop computers, portable computers, dedicated server computers, multiprocessor computing devices. Regardless of its specific configuration, the too dry material joint inspection system 100 may include, for example, a processing device 102, a memory 丨 丨 〇, more than one user interface device u〇, a display 130, and more than one input / output (1 / 〇 ) Devices 14, each of which is connected via a regional interface 118. The processing device 102 may include any custom-made or commercially available processing unit, one of several processors equipped with the solder joint inspection system 100, an auxiliary processing unit, or a central processing unit (cpu), semiconductor-based Microprocessor $ (in the form of a microchip), a macro processor, more than one application-specific sum circuit (ASIC), several appropriately-equipped digital logic gates, and other fairly familiar electronic groups Distribution, including discrete components in various combinations, to coordinate the overall operation of the solder joint inspection system 100. 17 535473 V. Description of the Invention (l5 The memory 110 may include electrical memory elements (such as random access memory (RAM such as DRAM, SRAM, etc.)) and non-electric memory elements (such as ROM, hard Disk, tape, CDROM, etc.). The memory 1 记忆 typically contains 10 / S 112, more than one application, such as solder joint analysis application 114. Those skilled in the art will understand the memory The 110 may (and typically will) include other components, which are omitted for brevity. These may include the main program being configured to control various aspects of the solder joint inspection mechanism. &Amp; More than one user user interface device 120 contains these components that a user can interact with with their solder joint inspection system 100. For example, in the case where the dry material joint inspection system 100 includes a personal computer (pc), these elements may include-a keyboard and a mouse. The solder joint inspection system here is expected to be used in extreme environments (such as near a solder flow machine). The components can include function keys or buttons, -touch sensitive Screen, a stylus, etc. (not shown), the display 130 may include a computer monitor or a plasma screen, or a liquid crystal display (LCD) as desired. Further referring to the first! FIG. / 〇device i4〇 can be adopted to facilitate the connection of the solder joint inspection system to another system and / or install more than one serial, parallel small computer system interface F. Universal serial busbar), Peng如 (such as eight :: two people): and / or other interface components' It can be used to communicate with the 5 inspection system. And-more than one remote data storage device == test measurement results. The network interface contains various components used to transmit and receive data over a network (not shown). For example, 18 535473 V. Description of the invention (a) 5 'The network interface device 150 彳 includes devices that communicate with input and output, such as a modulator / demodulator (such as a modem), and wireless (such as radio frequency). (RF)) receiving status, a telephone interface,-a connector, a router, a network card, etc. Various software and / or blades will be used to manage, coordinate, measure, and record estimates. Ten and compare the expected value with the measured value to generate an error value, and perform out-of-bounds analysis and other functions on the resulting error value. These and other functions related to the use of the reference solder joint inspection system 100 and the gripper body can be stored on any computer-readable medium for use in any computer-related system or method. In the context of this document, Φ brain-readable media represent electronic, magnetic, and child-friendly facilities that can contain or store electricity and are used in methods. This program = will be set by any computer-related system in the command execution system; ^ Hai computer-readable media, related use, such as computer-based systems, washing, and other processing彳 Order execution: also refers to other systems that execute these instructions. In this document ... ^ "optional media" may be any facility that stores, communicates, disseminates, or transports, in order to execute the system, the device: the following readable media such as electronic infrared or semiconductor systems, devices or playback media , But: a more specific example of a brain-readable medium (non-package:-electrical connection of more than one wiring 0). Including memory (read), read-only memory (= _ slices, random access memory (EPROM), electrical W erasure reading _), or flash memory, optical fiber second-read memory The portable read-only memory light 19 V. Description of the invention (17) CDROM. Note that the computer-readable media may even be paper or other suitable media on which the program can be printed electronically via, for example, optical scanning of the paper or other media, and the program can then be printed with appropriate The methods are compiled, interpreted or processed and then stored in computer memory. Figure 2 shows a sample point plot of sample data points measured and recorded from a particular type of BGA device package. As shown in the dot plot in Figure 2, the lean material includes more than 350 solder joints under inspection including the diameter in mn. One of the solder joints near the relevant pin on the left side of the trace is known to be defective and is indicated by the part number 21 °. The illustrated splicing junction 210 has a diameter of about MUm and is located near the center of the recorded diameter of the bga package. More specifically, the respective solder joints are recorded in the range of 29 to 31.5 mil, with a total variation in diameter of 2 5 mi1. In this data sheet it is clearly stated that it would not be possible to set a high or low threshold using the main acceptable solder joint defect isolation and / or identification of known solder joints. As a consequence, there is no acceptable solution for setting pass / fail thresholds under this profile. Similarly, FIG. 3 shows a tracing diagram of a sample data point recorded from another type of BGA device package and recorded in FIG. As shown in the tracing diagram in Figure 3, this data includes more than 350 solder joints inspected, including the diameter in md | units. The recorded diameter of each solder joint is in the range of 26.75 to 3 1.5 mil, and the total variation of the diameter is 4.75 mm, which is nearly two to seven tons of the diameter range recorded by the solder joint of the related BGA device shown in Figure 2. Alas, despite the dramatic increase in the range of recorded diameters, there is no single order in the tracing-solder joints are in place. Application may lead to inaccurate blemish determination.

Reference is now made to the side view of FIG. 4. As shown in FIG. 4, the printed circuit assembly 400 may include a BGA device 410 and a printed circuit board via :): The dry material bonding 4 丨 2 is electrically and physically connected at a point where it is substantially aligned. It is important to note that the icon is not to scale. The relative height (ie, thickness) of the BGA device 4o and the printed circuit board 42o used to form the printed circuit device 400 will often change, and the size of various solder joints formed by several solder balls will appear small.

As further shown in the side view of FIG. 4, the BGA device 41 will be wound into an upward curve so that the opposite end of the BGA device 410 will be "pulled away" from the mounting (ie, upper) surface of the printed circuit board 420. BGA devices can be entangled due to thermal swelling misalignment within the package and / or other reasons such as stress applied by the printed circuit board. Solder bonding 412 is set up around the material of the BGA device 41〇. Because the volume of the material (solder) in each solder ball remains fixed, these connection points are removed from each other by the “z” dimension with the mounting surface (the lower side of the BGA device 41〇 and the upper surface of the printed circuit board 420), and The focus plane 450 will have a reduced diameter when measured. As explained previously, coiling the BGA device will cause large variations in the measured diameter of the solder joint 412. Due to the upward curvature of the BGA device 410, the solder joint near the center of the BGA device 410 typically has a larger diameter than the solder joint on the outer edge of the BGA device 410. As shown in the side view of FIG. 5, the printed circuit assembly 5000 can include a BGA garment 5 1 0 and a printed circuit board "0 bonded by solder 4 ^ 2 21 V. Description of the invention (19) on Babe The back-to-back points are electrically and physically connected. Figure 5 is not shown to scale as in Figure 4. In Figure $ there are at least two factors that cause acceptable variation in the associated solder joint measurement of the BGA device 510 The result: the printed circuit board is coiled and the BGA device is tilted. The BGA device is tilted when there is more than one angle and other angles have different "z" values. In the case of the BGA device coiled shown in Figure 4, printing Circuit board winding may be non-linear and change in both X and γ dimensions (ie toward the page). The consequence is that these connection points are mounted on the surface (the lower side of the BGA device 5 10 and the upper surface of the printed circuit board 520). The dimensions are removed from each other by "z," and will have a reduced diameter when the focal plane 450 is measured. As previously explained, BGA garment winding can cause large variations in the measured diameter of the solder joint 5 12 and it is difficult to use this information exclusively as a pass / fail criterion for the solder joint inspection system 100 (Figure 1). index of. Now, according to the plan view of FIG. 6, it shows an exemplary method for assigning an exemplary I 600 to a number of solder joints 6 and 2 on the mounting surface of the device. As shown in Figure 6, the solder joint inspection system ιο is used to identify the center of the particular BGA device 600 which is currently being tested. After the center 61 of the BGA device 600 has been determined on the X-Y surface, the solder joint inspection system 100 can be used to determine and store the distance from the center 61 to the center of each individual solder joint 612. The importance of these distance measurements will be understood after viewing the sample point plots in Figures 7 and 8. Fig. 7 shows the tracing points. Fig. 7000 illustrates various conductive points of an exemplary Bga device type. The solder joint diameter is arranged at a distance of 6 mm from the center of the BGA device 600 (Fig. 6). Opposite to the sample points in Figure 2 The 535473 V. Description of the Invention (20) The data shows that there is a slightly linear relationship between the solder joint diameter expressed in mil and the solder joint center 610 distance. Similarly, Fig. 8 shows the plotting point. Fig. 800 is an illustration of various conductive points of an exemplary bga device type using a distance from the center of the BGAt to configure the solder joint diameter. In contrast to the sample points in Fig. 3 and the sample points in Fig. 7, 'the lean material exhibits a linear relationship between the solder joint diameter expressed in mil and the distance from the center of the solder joint. However, in the case of the BGA package type analyzed and traced in Figure 8, the slope of the linear relationship is negative for the distance of the respective solder joints from the center of the device. It is clear that when these viewpoints are equipped with more than one threshold value for each separate solder joint set at 4 BGA t, it is considered acceptable for such gates to consider that various solder joints arranged along the χ_γ surface can be expected to be acceptable. Variations are possible. For example, the threshold above the expected bond diameter can reflect the average diameter pair distance from the solder bond center associated with a particular printed circuit device. The upper m-monitoring value can be applied in a linear manner as a positive difference of the recorded average diameter versus distance for a particular printed circuit device. An actual solder joint diameter that exceeds the threshold between mounting surfaces is not quite close to the threshold above, can be considered to have solder that exceeds and can be labeled for further investigation. Similarly, the threshold below the solder joint diameter can reflect the distance of the diameter versus the solder joint center from the brush circuit device. This door-to-door value can be applied in a linear fashion as a fixed negative difference in average diameter versus distance recorded for a particular printed circuit device. Actual solder joint diameters that exceed the threshold below the distance between the mounting surfaces are not quite close, can be considered to have an open circuit condition and can be marked for further investigation. 535473 V. Description of the Invention (2ι Figures 9 and 10 present two plan views of exemplary BGA devices. Figure 9 shows a BGA device 900 showing solder joints arranged in rows and columns near the outer edge of the device. The surface map in Figure 9 shows that the female surface of the bga garment 900 is consistently co-surfaced with the X and Y dimensions of the solder joint inspection system 100 (Figure 1). For illustration purposes, the exaggerated diameter The figure reveals several solder joints 912 over the entire mounting surface. The diameters of the individual solder joints shown are actually not to scale to show the variation in the overall solder joint diameter on the individual solder joints of the bga device. As shown in Section 9 The surface view of the figure shows that the BGA device _ reveals a non-linear "z-degree variation in the diameter of each solder joint. The solder joint diameter variation is random over the entire mounting surface of the BGA device. Figure 10 The BGA device 1000 shown presents solder joints 1012 arranged in rows and columns in the installation table of the device. The surface of the device 1000's women's clothing is coplanar with the X dimension of the solder joint inspection system 1 (Figure 1). in order to For the sake of clarity, this exaggerated diameter diagram reveals several solder joints 2 on the two mounting surfaces. As shown in the second and first surface of Fig. 1G, the BGA device 1000 has a winding in a typical manner, and the solder joints near the 4 edges have the smallest The diameter of the solder joint, which is closer to the center of the BGA device, has the largest diameter. A better example of the improved solder joint inspection system, system 100 (Figure 丨), and the printed circuit used to adopt the test threshold value A related method,-nearby adjacent analysis is interesting for clothing (such as β GA device_). Each of the related solder joints is accepted by the entire volume of the circuit device. It is assumed that the package There is a change in the solder joint measurement, 24 V. Description of the invention (22) But the measurement variation between adjacent solder joints should be small. Each and every relevant solder joint of the BGA device can be matched as shown in the partial surface diagram of n Nearby solder joints. When the solder joint is located along the edge of the BGA device as the solder joint 1112a, five solder joints ⑴ ^ will form adjacent elements near the solder joint 1112a. When the solder joint is located at the center of the BGA device, such as solder joint 1112b, the two solder joints ⑴3 & will form the adjacent element near the solder joint 1U2b: the cow group. As further shown, a 'field' Solder bonding (that is, surrounded by eight phase #solder bonding-solder bonding) can be matched with eight solder bonding. Note that in addition to those shown in Figure n, there are several different methods that can be used to select adjacent pins. (Ie, solder bonding). For example, a particular number of rows or columns of solder bonding may be considered in various other methods for matching adjacent solder bonding with the solder bonding being tested. A different method may be used Based on solder joints from a particular nearby solder joint group—measurements rely on estimates of appropriate solder joint measurements. For example, the relevant measurement values of each solder joint in a nearby adjacent group can be used to set the desired measurement for the identified solder joint. In this regard, the mean, median, or average measurement in d can be used as the expected value of the solder joint identified by this?. In some configurations, the -estimated value can be predicted. For example, the height of a solder joint can be measured, and the phase diameter of the material can be determined by knowing the volume of the original solder ball. Danjin: The value of the adjacent error in the vicinity of the latter can be compared with the actual solder joint measurement. "The measurement of the near-neighboring group of Qian can be derived from the expectation of the material joint. V. Description of the invention (23) For each several solders The joints are calculated. The adjacent adjacent error data of the previously described exemplary BGA device type is shown in the tracing graph of Figure 12.

In other words, the data trace diagram 1200 shows the relationship between the adjacent errors in the vicinity and the pins (ie solder joints) classified by the type and amount of the BGA device. As shown in the data plot 1200 of Figure A, the error sign of the exemplary bgA 346 device is significantly different from the error sign of the exemplary BGA 347 device. Now refer to Figure 13 to analyze the plot of the adjacent error bounds. The synthesized data trace graph 1300 shows a square box trace graph analysis of nearby data trace graphs 1200 (Figure 12). The square box plot is an effective visual representation of central trend and dispersion. It displays the 25th, 50th, and 75th percentiles as well as the minimum and maximum values simultaneously. The "square box" of the square box plot point chart shows the middle or "most typical" value of 50%, while the "branch and whisker" of the square box plot point chart shows the more extreme value. The height of the square box 1302 and the "M" of each BGA device is a representative quarter-digit pitch (OR). It has been found that considering any diameter error more than three times the top of each square box 1302, 1304 is an effective pass / fail gate pinch value of the BGA device, such as a square box trace of a composite plot of 目 13 mesh According to the dot chart data, the BGA 347 device type does not have an adjacent error value outside the boundary that exceeds the planned value (three times the IOR). In this case, the improved solder joint inspection system 100 has accurately reported that there are no defects associated with solder joints of the exemplary BGA 347 device. For example, in the case of drawing a synthetic box with a figure of 1300, it is impossible to say the same thing about the out-of-bounds analysis of the solder joint error related to the exemplary B G A 3 4.6. As shown in I, several nearby neighboring error values have passed the planned error 26 535473

27 535473

V. Description of the Invention (25) Certain other characteristics of solder joints in one column of the X dimension and / or solder joints in one row of the γ dimension can be used to determine the best for the corresponding data set formed by the measured diameter Adaptive polynomial. The resulting best-fit polynomial can then be used to generate a desired value for each solder joint. In other cases, the expected value of each individual solder joint can be determined as a mathematical result from the expected best fit result in the X dimension and the expected best fit result in the γ dimension.

Alternatively, a Fouier analysis can be applied to the data being measured to produce a desired value for each force dry material joint. As already known,-transform into a two-dimensional representation of the weighted sum of Sm two and-. The transformation of $ jin advances from a continuous or discrete spatial domain to a continuous frequency domain. Therefore, the F_ier transform can be used to analyze the data in the frequency domain for high-frequency changes of the measured diameter. As is customary, high frequency variations can be removed via a properly configured chirp. An inverse F_k transform can then be applied to the data to derive the lookout value for each solder joint. Regardless of

What is the method used to generate these expected values? The low frequency (acceptable) of the measured values of the entire array package (Luan Xian A ~ 7) is again being found in the search for the expected value and the modified pass / fail gate root value. reflect. The system 100 can be programmed to store and analyze errors for foreign objects. These foreign objects are unanticipated (such as high-frequency) variations in solder joint measurements, which have been followed as shown in step ⑷0. The 'improved solder joint inspection system' can be programmed to compare the estimates generated at each step Or the respective measured value of each expected solder joint with each solder joint recorded in step 1406. As mentioned above and shown in step 1412, the improved solder joint inspection system is 28 535473. V. Description of the invention (26) Accurate index of solder joints caused by mosquito bug BGA device. It should be understood that the process steps shown in the flowchart of Figure 14 can be repeated to complete solder joint analysis of other printed circuit devices mounted on the printed circuit assembly. FIG. 15 is a functional block diagram showing various exemplary components of the solder joint analysis application 114 of FIG. In this regard, the solder joint analysis application < U4T includes recording logic 1500 configured to receive one or more of the characteristic values observed in various images generated and analyzed by the solder joint inspection system 00. The solder joint analysis application 14 may also include logic 15 10 each solder joint configured to be tested determines a desired value. As previously described, the logic 1510 may use any number of methods to generate a desired measurement for each individual solder joint, which takes into account variations between the mounting surface of the relevant device and the printed circuit board. As shown in Figure 15, record logic 1500 and logic 1510 can be configured to provide information about each individual solder joint to comparison logic 1520. Second, the comparison logic can be configured to determine the difference between the measured (ie recorded measurement) and the relevant expected value for each individual solder joint being observed. As further shown in this block diagram, the comparison logic 1520 can be configured to deliver each individual error data value to an error value data array 1530. Next, the error value out-of-bounds analysis logic 1 540 can be configured to receive a number of 5 Wu differences and perform out-of-bounds analysis on the data. After the error value foreign object has been identified in the out-of-bounds analysis logic 1540, the solder joint analysis application U4 can deliver identification information related to out-of-bounds data values that exceed a threshold value to the bound 29 535473 V. Description of the invention (27 = report logic, 550 The logic of the out-of-bounds error report is as follows: the system provides a position and / or other identification elements to one or more peripheral devices that are in line with the solder joint inspection system 1GG. Figure 16 is a flowchart showing the identification of solder joints. Defective method 0, which can be implemented by the circuit inspection system of Fig. 1. In this regard, the modification of the material bonding system can be implemented by measuring and recording the physical characteristics of each solder joint that is related to the specific characteristics. • Improved solder joint inspection system after mother-to-solder bonding. The information about array package winding and / or printed circuit board winding can be used at step 1604 to estimate the expected solder-to-measuring solder bonding. For example, as shown in step 1606, the improved solder joint inspection system TI can be configured to compare the expected value with that of each of the tested subjects. ^ The mother of a sacrifice-solder joint generation-error value If the display is deleted in steps, ^ U606 generated several error values can be applied in an error data value out-of-bounds analysis to identify defective joints. Second, ..., improved; C dry material joint inspection system 100. The specific embodiment has been disclosed in detail in the description and the figure for the purpose of example. It will be understood by those skilled in the art that changes and modifications can be made without departing from the spirit of the invention as set forth in the following application. Made. For example, other solder joint measurements related to non-array packages can be expected to reflect low frequency variations for various reasons, including the above-mentioned mounting surface due to "Z" | degree variations = results. Therefore, it has- More than two related technologies are used to adopt pass / fail thresholds for non-array sealing I solder joints. This disclosure intends to include the application of these technologies. 30 535473 V. Description of the Invention (28) Component Labeling Table Component Number Translation Component Number Translation 100 Solder bonding inspection system 550 Focusing plane 102 Processing device 600 BGA device 110 Memory 610 Center 112 Working system (0 / S) 612 Solder bonding 114 Material bonding analysis program 612a solder bonding 118 area interface 612b solder bonding 120 user interface device 700 trace point 130 display 800 trace point 140 input / output (I / O) device 900 BGA device 150 network interface device 910 solder joint 200 traces 912 solder joints 210 solder joints 1000 BGA device 300 traces 1012 solder joint 400 error assembly 1100 BGA device 410 BGA device 1112a solder joint 412 solder joint 1112b solder joint 420 printed circuit board 1113a solder joint 450 focus plane 1113b Solder Bonding 500 Printed Circuit Assembly 1200 Plotted Drawing 510 Printed Circuit Device 1300 Plotted Drawing 512 Solder Bonded 1302 Square Box 520 Printed Circuit Board 1304 Square Box 31 535473 V. Description of the Invention (29) Component Numbering Table Component Number Translation Name Component Number 1400 method 1402 step. 1404 step 1406 step 1408 step 1410 step 1412 step 1500 logic 1510 logic 1520 logic 1530 error value data array 1540 logic 1550 logic 1600 method 1602 steps 1604 step 1606 step 1608 step 32

Claims (1)

535473 1. A method for adopting a test gate pin value, including the following steps: Obtaining (H02) position information for several solder joints (412) on a printed circuit device (410); and obtaining (1404) indicating the printing Variation in the distance between the mounting surface of the circuit device (41) and a printed circuit board (420); the record (i406) is used to couple the number of the printed circuit device (410) to the printed circuit board (42) Measurement of the physical properties of each solder joint (412); the individual solder joint estimates (i408) in response to the variation in the distance between the mounting surface of the printed circuit device (41) and the printed circuit board (420) may be The range of accepted measurements; and setting (1412) at least one threshold value in response to the range. 2. The method as described in item 丨 of the patent application scope, wherein the estimation step (1408) includes performing statistical analysis on the recorded measurements of the identified adjacent solder joints (13). 3. The method as described in item i of the scope of patent application, wherein the setting step further comprises: comparing (1606) the threshold value with the recorded measurement as a number of solder joints on the printed circuit device (4U)) Generation-error value; and performing an out-of-bounds analysis (160) on the plurality of error values to establish at least one threshold value. 4. The method as described in item 3 of the scope of patent application, wherein the step (⑽6) of comparing the threshold value to the recorded test 4 includes a mathematical combination of the measurement of the value and the job record. 5.-A method for identifying solder joints, including the steps: 33 535473 535473 6. Scope of patent application 9. The system described in item 8 of the scope of patent application, 1 further includes: a facility (114) for analyzing these several error values to identify solder joint defects. 10. The system described in item 9 of the scope of patent application, wherein the facility for analysis includes a box plot (1304). 35