Masanori Noguchi

Study for a defect detection system with capacitance on the printed wiring board

Recently consumer products focused on electrical devices are miniaturized and its packaging size becomes smaller and smaller such as cellular phones, digital cameras and etc. It means that an innovation to miniaturize the printed circuit board (PCB) is required. Along with this requirement of the minute PCB, a technique of the fine pattern design and tiny component mounting on the board must be newly developed. Regarding a growing trend of the minute and multi-layers design of the PCB, a line width of the circuit pattern is reduced up to 25 [μm] and then the defect inspection is proposed as the most important technology. Therefore we study a new system development for the defects which are difficult to inspect on the fine patterns. To find the defects at a continuity test is done by the non-contact method and the inspection for finding the position of the defect is request. In this report, as the way of the continuity test by using the probe, we have an experiment of the contacting method. Moreover, we can compare it with the non-contact method on the board.

A Study on Defect Inspection System for Minute Printed Wiring Boards by Using Capacitance Type Sensor

今日の携帯電話に見られるように電子機器がますます小型化し，プリント配線板（PWB）にもより微細なものが求められている。さらに，この微細化への要求に加え，新しいパターン設計と電子部品の搭載技術は共に開発されなければならず，より正確な位置決め精度の重要性が増してきている。例えば，PWBのフレキシブル基板の多層化設計の統合へ進むなかで，配線幅が25 μmへと向かっている。本研究の目的は，PWBの正確な自動測定技術のニーズに答えることにある。従来のパターンマッチングによる画像処理検査や光学顕微鏡方式などの複雑な測定技術が必要であったが，われわれはこれらの自動測定技術にとって代わる新たな設計による測定法を確立したものである。今回の報告では，検査を行うためのプローブ形状と精度向上のための補正方法を示し，実験により150 μmまで細くしたPWBの欠陥を5%以内の精度で測定できることを示した。

Study on minute printed wiring board inspection system with a multi-function probe

Currently, there are electrical inspection methods for detecting defects in printed wiring boards. However, the reliability of these inspections is less than ideal. In order to improve these methods, not only is it necessary to have a system that is resistant to wear, high speed, with stable data acquisition, but a system that is able to perform on high-density circuits. This research focuses on a development of a non-contact probe inspection system for printed wiring boards. In order to eliminate connectivity defects that arose from contact probes used in previous inspection methods, this new system utilizes a probe with an attached dielectric material. In order to tailor to boards with very fine wiring, it is necessary for the system to conduct high-precision positioning as well as to capture signals within a microscopic region to detect even the smallest defects. This paper is concerned with the development of a new non-contact inspection system with multi-function probe to detect defects of printed wiring boards.