KOSEN 한인과학기술자네트워크

>안녕하세요. 경희대학교에 재학중인 학생입니다. > >날로 번창하는 것을 보니 저도 기쁘군요. > >다름이 아니라.. > >산업용 디지털 X-ray PCB 검사장치에 대한 다양한 방법에 대한 사항을 알고 십습니다. > >1)산업용 CT, laminograpny등의 기본 원리 및 장치 구조들에 대해 알고 싶어요 > >2) 현재 세계적인 경향도 더불어 알았으면 좋겠습니다. > >관련 자료가 있으면 꼭 좀 보내 주시고,,있는 곳을 알려주세요.. > >그럼 수고 하시고요.. > >새해 복 많이 받으세요. ------------------------------------------------------------------ 1. eal-time X-ray inspection of 3-D defects in circuit board patterns Doi, Hideaki (Hitachi, Ltd) Suzuki, Yoko | Hara, Yasuhiko | Iida, Tadashi | Fujishita, Yasuhiro | Karasaki, Koichi Source: IEEE International Conference on Computer Vision Jun 20-23 1995 1995 Sponsored by: IEEE IEEE p 575-582 Abstract: This paper reports/defect-detection techniques using X-ray in order to find three-dimensional defects such as tunnels in printed circuit board (PCB) patterns. X-ray images of fine PCB patterns, however, show patterns on more than layer, have degrees of distortion that vary over an image, are subject to intensity variation due to fluctuations in the intensity of the X-ray source, and so on. To overcome these problems, we examined distortion caused by perspective transform on sphere surface of an X-ray detector and developed defect-detection algorithm based on feature extraction. Fluctuation of X-ray strength and heavy shading of the acquired image are compensated by signal processing. Evaluation of the system confirmed that the system could detect defects deeper than 20μm and with surface areas greater than 70×35μm2 in fine PCB patterns and that the inspection time for a 600×800mm2 PCB was only 20 minutes. In English 2. Inspection of ball grid array (BGA) solder joints using X-ray cross-sectional images Roh, Y.J. (Korea Advanced Inst of Science and Technology) Ko, K.W. | Cho, H.S. | Kim, H.C. | Joo, H.N. | Kim, S.K. Source: Proceedings of SPIE - The International Society for Optical Engineering 3836 Sep 21-Sep 22 1999 1999 Sponsored by: SPIE Society of Photo-Optical Instrumentation Engineers p 168-178 0277-786X Abstract: The ball grid array(BGA) chip is widely used in high density printed circuit board(PCB). However, inspection of defects in the solder joints is difficult by visual or a normal x-ray imaging method, because unlike conventional packages with gullwing type leads, solder joints of the BGA are located underneath its own package and ball type leads. Therefore, x-ray digital tomosynthesis(DT), which form a cross-sectional image of 3-D objects, is needed to image and inspect the solder joints of BGA. In this paper, we propose a series of algorithms for inspecting the solder joints of BGA by using x-ray cross-sectional images that are acquired from the developed DT system. BGA solder joints are examined to check the alignment between the chip and pad on a PCB, bridge(electrically short), adequate solder volume. The volume of the solder joint is represented by a gray level in the x-ray images: thus solder joints can be examined by use of the gray-level profiles of each joint. To inspect and classify various defects, pattern classification method using a learning vector quantization(LVQ) neural network and a look up table(LUT) is proposed. The clusters into which a gray-level profile is classified are generated by the learning process of the network by using a number of sampled gray-level profiles. A series of these developed algorithms for inspecting and classifying defects were tested on a number of BGA solder joints. The experimental results show that the proposed method yields satisfactory solutions for inspection based on x-ray cross-sectional images. In English 3. X-ray systems fill modern PCB inspection voids Miller, Don (CR Technology) Source: EE: Evaluation Engineering v 36 n 11 Nov 1997 A. Vernon Nelson Associates p 48-50 0149-0370 Abstract: Today's high-density chip packages including ball grid arrays (BGA), microBGA, and flip chips have opened a vast array of possibilities for printed circuit board (PCB) designers. Along with the opportunities come some tough inspection tasks that must be done quickly and efficiently to bring competitive products to market. To faced this dilemma and to meet the demands placed on devices, PCB manufacturers are taking a closer look at X-ray inspection. This technology helps to set up and control the manufacturing process, analyze prototypes, and identify process faults. In addition, this technology is proving to be an effective and cost-efficient tool to discover shorts, opens, voids, and misalignments of the solder balls on the manufactured boards. In English 4. Implementing an effective solution for inspecting BGAs Zarkoob, Ben (Siemens Information Communication Networks) Source: EE: Evaluation Engineering 39 10 Oct 2000 A. Vernon Nelson Associates 3 pp 0149-0370 Abstract: Ball grid array (BGA) is a new technology which replaces the conventional devices on the PCBs. X-ray inspection system can easily locate critical problems associated with the solder reflow. They provide for checking of the soldered joints and to inspect system through-holes on the PCB. It permits precise and accurate hole inspection. The advantages of X-ray inspection systems in the PCB industry are presented. In English 5. AOI and x-ray find a niche in assembled PCB inspection Markstein, Howard W. Source: Electronic Packaging and Production v 38 n 15 Dec 1998 Cahners Publ Co p 30-34 0013-4945 Abstract: Automated optical inspection (AOI) and X-ray inspection of assembled printed circuit boards (PCBs) are key operations prior to electrical testing. The results include higher yields at electrical test and a reduction in time-consuming diagnostics. In English EI99034587407 >

아래의 자료들은 산업기술정보원(http://www.kiniti.re.kr)을 통해 검색된 자료입니다. 웹을 통해 원문신청이 가능합니다. 참고해 보시기 바랍니다. * X-ray computed laminography: an approach of computed tomography for applications with limited access, Gondrom, S.; Zhou, J.; Maisl, M.; Reiter, H.; Kroning, M.; Arnold, W.;, Nucl. Eng. Des. (Netherlands) (June 1999), pp141-7, 12 ref(s) CODEN: NEDEAU Abstract : Computed laminography (CL) is an image forming method of X-ray testing that yields images of object slices by a simple linear translation of the object relative to the tube-detector system. No relative movement of the X-ray tube to the detector is needed and in contrast to classical laminography all object layers can be obtained by one scan. Moreover CL turns out to be equivalent to a computed tomography (CT) with a limited angular region, which allows the reconstruction of object slices using slightly modified CT algorithms, resulting in a higher resolution compared with simple tomosynthesis in the case of classical laminography. * Improvements to X-ray laminography for automated inspection of solder joints, Sankaran, V.; Kalukin, A.R.; Kraft, R.P.;, IEEE Trans. Compon. Packag. Manuf. Technol. C, Manuf. (USA) vol.21, no.2 (April 1998) (USA), p148-54, 16 ref(s) CODEN: ITCMF2 Abstract : With the increased usage of fine-pitch assemblies and ball grid array (BGA) packages, there is a dramatic increase in demand for automated defect detection techniques such as X-ray laminography. However, the limitations of this imaging medium are not well understood by the industry. This article addresses the need for improving the imaging resolution of X-ray laminography, particularly for accurate three-dimensional (3-D) measurement of solder joint structures. The authors have developed a new method for reconstruction of the laminographs which improves the signal-to-noise ratio (SNR) of the laminographs significantly and enables better 3-D visualization of solder shape. Application of automated solder joint defect classification using neural networks has also been studied. Components with BGA, gull-wing and J-lead joints were imaged and several neural network methods were used to identify different classes of defects particularly significant to each type of joint. A novel probabilistic neural network approach for two-dimensional (2-D) image classification has been developed which performs as well as or better than a conventional backpropagation network * Unpowered opens test with X-ray laminography, Oresjo, S., Proceedings. International Test Conference 1997 (IEEE Cat. No.97CH36126) (1997), pxiv+1054, pp276, Abstract : It is shown how X-ray laminography can be used to detect solder opens. With this method X-ray images are taken of the device under test (DUT). The lead content in solder makes the solder joints appear clearly in the image. Using image processing algorithms and also calibration information, the captured image of the solder joint is automatically translated into key mechanical measurements of the solder joint, such as heel height, center height, toe height, average height, fillet length and width at the toe and the heel. An important feature of this method is that these mechanical characteristics of the solder joint are used by the image processor to automatically determine an open solder joint from a good solder joint. All pins, including VCC and grounds, almost all component types, including bypass capacitors, can be inspected for opens as well as marginal opens. Typically over 98% of all solder joints on a PCB can be inspected * Development of an inspection process for ball-grid-array technology using scanned-beam X-ray laminography, Rooks, S.M.; Benhabib, B.; Smith, K.C.;, IEEE Trans. Compon. Packag. Manuf. Technol. A (USA) vol.18, no.4 (Dec. 1995) (USA), p851-61, Abstract : An inspection process based on scanned-beam X-ray laminography (SBXLAM) is proposed herein for quantitatively monitoring the quality of ball-grid-array (BGA) joints. The long-term reliability of the BGA joints depends on the component-assembly process producing joints with sufficient solder volume and proper alignment. Inspection algorithms were developed to measure the critical BGA-joint characteristics, including the alignment between the ball and the PCB pad, the solder thickness, and the average joint-diameter, and thus, determine whether the joints are defective. The performance of the inspection algorithms was evaluated by inspecting samples with defects that were independently verified * Laminography generates real-time, data for on-line solder quality inspection, Adams, J.A., Proceedings of the Printed Circuit World Convention 5 (1990), p744, ppA10/3-14, 13 Abstract : The manufacture of circuit boards is becoming ever more complex due to the increasing lead count, decreasing lead pitch, and the switch to double-sided surface mount and Chip-On-Board designs. Since quality cannot be 'inspected into' a product it becomes essential that the manufacturing engineer obtain real-time, data for on-line process control in order to keep board yields high. A new technology, Scanned-Beam Laminography (SBL), solves this problem by generating laminographic X-ray slices that are automatically analyzed against original CAD designs to provide quantitative data on the structure of each solder connection. This paper discusses the generation of quantitative, on-line, real-time, process control data through the use of automated Scanned-Beam Laminography, and the application of the resulting data to the soldering process. In addition, it addresses the accuracy and repeatability of SBL-based automated solder joint inspection and process control data for bridging, voids, misalignment, lifted-leads, and insufficient and excessive solder. Specific case study results are presented * Design of an experimental system for dual energy X-ray CT, Sukovic, P.; Clinthorne, N.H.;, 1999 IEEE Nuclear Science Symposium. Conference Record. 1999 Nuclear Science Symposium and Medical Imaging Conference (Cat. No.99CH37019) (1999), Abstract : We present the design of a dual energy (DE) X-ray computed tomography (CT) test bench. It employs amorphous silicon (a-Si:H) imaging arrays and helical cone-beam geometry. Our goals are to evaluate: (1) the applicability of a-Si:H imaging arrays for tomography; (2) how our previously published dual energy penalized weighted least squares (DE PWLS) reconstruction method performs on experimentally acquired data; and (3) the optimal imaging geometry. 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