傾斜型X線CTを用いたBGAはんだ接合部の異物検査手法  [in Japanese] Inspection Technique of Foreign Objects in BGA Solder Joint Using Oblique X-ray Computed Tomography  [in Japanese]

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Abstract

プリント配線板にBGA(Ball Grid Array)やCSP(Chip Scale Package)などを実装する場合,はんだ接合部に混入する異物は接合強度の低下を招く。従来から広く行われてきた可視光を用いた外観検査手法では,はんだに隠れる部分の異物は検査されてこなかった。一方,X線CT(Computed Tomography)方式で得られる水平スライス画像では,異物が存在する接合部の情報をスライス画像として得ることができ,それらを自動的に検出することができれば実装品質の向上が期待できる。そこで本稿では,はんだ接合部を撮影したCTスライス画像から,異物を自動的に検出する手法について提案する。本手法では,異物混入によって生じるはんだ接合部の形状変化に着目して,それを特徴づける複数の値を算出し良否判定を行う。実際に異物の混入したプリント回路板を用いて検証を行った結果,検出正解率98.9%で異物検出することができ,本手法の有効性が確認できた。

Foreign objects in a solder joint could deteriorate the joint strength when mounting BGA (Ball Grid Array) packages or CSP (Chip Scale Package) on printed circuit boards. However, foreign objects within solder bumps are not detected by optical inspection which has been used widely. Recently, X-ray computed tomography (CT) for the inspection of printed circuit boards has been developed. X-ray CT visualizes the foreign objects inside a solder joint. If they are automatically detected, higher soldering quality is expected. In this paper, we propose an automated detection method of foreign objects in solder joints using CT slice images. In the method, some characteristic values are identified which show the solder joint deformation. In the experiments, actual mounting substrates involving solder bumps contaminated by foreign objects were checked using the proposed method. The detection accuracy rate reached 98.9%, which clearly indicates that the proposed method is useful in practice.

Journal

  • Journal of The Japan Institute of Electronics Packaging

    Journal of The Japan Institute of Electronics Packaging 13(1), 63-70, 2010-01-01

    The Japan Institute of Electronics Packaging

References:  7

Codes

  • NII Article ID (NAID)
    10025984502
  • NII NACSIS-CAT ID (NCID)
    AA11231565
  • Text Lang
    JPN
  • Article Type
    ART
  • ISSN
    13439677
  • NDL Article ID
    10549752
  • NDL Source Classification
    ZN33(科学技術--電気工学・電気機械工業--電子工学・電気通信)
  • NDL Call No.
    Z74-B258
  • Data Source
    CJP  NDL  J-STAGE 
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