Multilayer printed wiring board and method of measuring characteristic impedance

Abstract

A multilayer printed wiring board having a compact test coupon formed on each of the signal wiring layers is provided, and accurate and efficient method of characteristic impedance measurement for each signal wiring layer is realized. The test coupon is constituted by a plurality of linear parts extending parallel to each other and folded-back parts mutually connecting the linear parts. A through hole is provided for serially connecting the respective test coupons of the signal wiring layers adjoining each other. Two measuring pads, one is connected to one end of the serially connected test coupons and another is connected to the ground layer, are also provided. The measurement is performed by applying a step pulse between two measuring pads and measuring voltages of reflection waves from the serially connected test coupons.

Description

technical field [0001] The present invention relates to a multilayer printed wiring board on which electronic circuit components are mounted, and a method of measuring characteristic impedance of signal wiring formed on the multilayer printed wiring board. More specifically, the present invention relates to a technique for measuring the characteristic impedance of signal wiring of a multilayer printed wiring board using a TDR (Time Domain Reflectometry) method. Background technique [0002] In recent years, as the density requirements for printed wiring boards have increased, a plurality of wiring boards formed with wiring patterns (patterns) on them have been pressed into three or more layers including the surface wiring board layer. A multilayer printed wiring board is formed. In addition, the operating speed of electronic circuit components mounted on multilayer printed wiring boards is also increasing. In an electronic circuit element operating at high speed, reflected...

AI Technical Summary

Problems solved by technology

However, in this technique, the characteristic impedance of the signal wiring on the printed board is calculated by measuring the cross-sectional shape of the wiring formed as a sample, so it is difficult to measure the characteristic impedance accurately

In order to measure the characteristic impedance electrically accurately, a sample having the shape shown in Fig. 6 is required, so the area occupied by the sample increases

[0006] In addition, when measuring the characteristic impedance using a conventional sample as shown in FIG. 6, it is necessary to measure the characteristic impedance of each signal wiring layer separately using the TDR (Time Domain Reflectometry) method, so it takes a long time to perform the measurement.

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