KOSEN 한인과학기술자네트워크

원하시는 것과 같은 경향 및 종류 등에 대해 나와있는 자료를 찾기는 어려웠습니다. 검색을 하다 보니 대체로 PCB X-ray 검사 시스템을 개발하는 회사 위주의 사이트들이 많았습니다. 이런 사이트들을 통해서 경향이나 종류등을 파악하시는 것도 좋을 것 같습니다. 아래의 사이트는 PCB x-ray inspection system과 관련하 참고문헌들이 나와있습니다. 참고해 보시기 바랍니다. http://lca.kaist.ac.kr/~arnold/Publications.html 아래의 문헌도 참고해 보시기 바랍니다. 개인저자 Brown, Kerry ; Bolliger, Bruce 논 문 명 X RAY IMPROVES PCB ASSEMBLY - by Kerry Brown and Bruce Bolliger X-ray laminography sees through components for process control. / 발행사항 1994 기타로 다음 사이트들도 참고해보시기 바랍니다. http://www.qualitymag.com/articles/1999/apr99/0499f9.html http://www.emtmagazine.co.uk/archives/September99/technicalarticlesep99xray.html >안녕하세요. > >다음의 사항에 대한 내용을 알수 있나요? > >현재 전세계적인 PCB X-ray 검사 시스템의 경향 및 종류 등에 대한 내용을 알 수 있나요? 또한 관련 내용이 잘 나와있는 잡지나 보고서을은 어떤 것이 있는지 알수 있는지요? > >너무 광범위한 질문 같은데 혹시나 구할수 있지 않을까해서 적습니다. > >그럼 답장 기다리겠습니다. > >수고하십시오..

>안녕하세요. > >다음의 사항에 대한 내용을 알수 있나요? > >현재 전세계적인 PCB X-ray 검사 시스템의 경향 및 종류 등에 대한 내용을 알 수 있나요? 또한 관련 내용이 잘 나와있는 잡지나 보고서을은 어떤 것이 있는지 알수 있는지요? > >너무 광범위한 질문 같은데 혹시나 구할수 있지 않을까해서 적습니다. > >그럼 답장 기다리겠습니다. > >수고하십시오.. --------------------------------------------------------------------- These paper were published on x-ray analysis of PCB. Real-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 12 Refs. EI95082831890 2. Mechanical reliability and failure analysis of PBGA packages soldered on electroless Ni/immersion Au and organic coated Cu Mei, Zequn (Hewlett-Packard Co) Callery, Patrick Source: American Society of Mechanical Engineers (Paper) Nov 16-21 1997 1997 ASME 10p 0402-1215 Abstract: The mechanical reliability of thermal enhanced plastic ball grid array (PBGA) packages with 352-540 pin count and 27 gram heatsinks was evaluated by shock and vibration tests. The PBGA packages soldered on the printed circuit board (PCB) pads of organic coated copper (OCC) finish survived the tests, while the PBGA packages on the PCB pads of electroless nickel (Ni)/immersion gold (Au) finish failed because of a brittle fracture at the interface between PBGA solder balls and PCB pads. Failure analysis of the brittle fracture was performed to identify the root cause. XPS (X-ray photoelectron spectroscopy) analysis of the un-soldered electroless Ni/immersion Au finish revealed that phosphorous (P), which was introduced in the Ni during electroless Ni plating, accumulated at the interface between Ni and Au. X-ray diffraction showed that electroless Ni was amorphous with supersaturated P. XPS and energy dispersive X-ray analysis (EDXA) of the brittle fracture surface indicated that the fracture occurred in a region of 100 angstroms thickness where tin (Sn), P, and Ni concentrations abruptly changed. The most likely mechanism for the brittle fracture was the presence and segregation of P in electroless Ni which degraded the interfacial strength between Ni3Sn4 intermetallic and Ni. Brittle fracture of the interfacial intermetallic Ni3Sn4 and oxidation of the Ni surface through the porosity in the immersion Au were other two possible mechanisms. In English 12 Refs. EI98024046412 Ei tagged | Document availability and cost 3. 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 18 Refs. Ei tagged | Document availability and cost 4. New method for image separation of overlapped images from a two-layered printed circuit board (PCB) An, Jinung (Korea Advanced Inst of Science and Technology) Cho, Young-Bin | Gweon, Dae-Gab Source: Image and Vision Computing v 15 n 11 Nov 1997 Elsevier Science Ltd p 861-866 0262-8856 Abstract: Conventional laminography provides cross-sectional X-ray imaging which separates the top and bottom sides, or any other layer of the printed circuit board (PCB), into separated images. However, only an image on the focal plane is obtained by a set of projections. Furthermore, the image is blurred by superimpositions of the out-of-focus structures. This paper presents a new method for image separation via object translation with a moving X-Y table instead of synchronously rotating or translating two components, i.e. a source and detector. This method uses a recursive process with a simple mathematical function which is derived analytically by the X-ray projection geometry. An X-ray imaging system has been constructed for the purpose of evaluating the proposed method, and was used for the test sample experiments. The experimental results confirm that the method is a powerful tool for separating objects from overlapped X-ray images. In English 16 Refs. EI98013998984 Ei tagged | Document availability and cost 5. Real-time X-ray image enhancement as a PCB inspection and evaluation tool Lin, Robert Jr. (CR Technology, Inc) Source: Electronic Manufacturing v 36 n 6 Jun 1990 p 26-28 0895-3708 Abstract: X-radiographic film exposure as used in traditional electronic applications requires high expertise yet offers limited image evaluation. But its high cost is one of the major limitations. These costs are also dependent upon whether the facility had its own developing capabilities or if it used outside services. In either case, the investment must be considered major. It is pointed out how x-radiography and integrated real-time computer image processing may be combined to provide a real-time X-ray image enhancement tool that improves on the deficiencies of traditional x-radigraphic film exposure. In English Ei tagged | Document availability and cost 6. 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 Ei tagged | Document availability and cost 7. Process yield and reliability of 0.65 mm pitch technology in surface mounting Liu, J. (IVF The Swedish Inst of Production Engineering Research) Source: Soldering & Surface Mount Technology n 16 Feb 1994 p 5-10 0954-0911 Abstract: This paper describes the influence of soldering parameters on solder joint quality and reliability of 0.65 mm pitch QFP technology. Soldering process parameters such as soldering temperature conveyor speed and board size have systematically been varied using factorial experimental analysis. Solder joint quality has been characterised in therms of solder ball formation, open joints and porosity behaviour. Equipment used includes microfocus X-ray non-destructive testing apparatus, optical and scanning electron microscope. The reliability of joints has been investigated by temperature cycling from -55 to +125 °C for 1000 cycles. The time per cycle was approximately 1 hour. The results from the present work show that pad layout on the printed circuit board (PCB) and the quality of pretinning during PCB production have a considerable influence on the solder joint yield. In English 11 Refs. EI94091390795 Ei tagged | Document availability and cost 8. NASA evaluates automated inspection systems Savage, Robert M. (NASA Goddard Flight Cent) Fan, Mark S. | Park, Hyun Soo Source: Test & Measurement World v 13 n 12 Nov 1993 4p 0744-1657 Abstract: Suppliers of automated inspection (AI) systems say their systems offer relief from the labor-intensive and often subjective manual inspection of solder joints in high-volume PCB production runs. Therefore, at NASA's Goddard Space Flight Center, the authors evaluated six AI systems to determine if they were suitable for inspecting NASA's high-reliability PCBs. The authors found that the advantages offered by AI systems in high-volume/low-mix applications do not apply to NASA's low-volume/high-mix PCB applications. The long setup and test times required for these systems cannot be justified for NASA's short production runs. AI systems were incapable of identifying critical defects in many situations where a human inspector could readily identify them. Yet, an AI system can uncover hidden defects, which is essential for meeting NASA's quality standards. It was therefore concluded that an AI system could supplement -- not replace -- manual inspection for NASA's low-volume, high-reliability surface-mount solder joints. In English EI94021207389 Ei tagged | Document availability and cost 9. Real-time X-ray inspection. Essentials of the technique Pascente, Joseph E. (Lixi, Inc) Source: Electronic Manufacturing v 36 n 6 Jun 1990 p 24-25 0895-3708 Abstract: X-rays have not changed significantly since their discovery. However, their applications have grown as manufacturers and customers demand higher levels of inspection quality. X-ray systems have developed from closed expensive systems to real-time portable devices that can be used in conjunction with computer and machine vision. The benefits of real-time vs. film processing for PCB's and components go beyond its adaptability to production-line inspection. In English Ei tagged | Document availability and cost 10. 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