| 摘要 |
PURPOSE:To attain the most precise pattern designing by making combination of a straight line part and oblique line parts of 45 deg. and 135 deg. a basis, and specifying the ratio of line width of the oblique line part and line width of the straight line part, pad pitch in each channel and the relation of adjoining pitch interval of straight line part of leader lines. CONSTITUTION:Following conditions are set in a leader line pattern. (1) Relation between line width d of straight line part and line width S of a leader line 27 in each channel is made to S=2<1/2>d. (2) The distance DELTAX between the intersection B of oblique line part side line AB and pad side line EC and a pad area 40 is made DELTAX=D-2d. (3) T=2P' is satisfied between pitch P' of straight line part of the leader line 27 and pitch T of the pad 26 (accordingly, T=2P is also satisfied). From conditions (1) and (2), channel resistance of all channels can be made equal, and from the condition (3), for instance, all of points A and F form a line on a straight line of alpha=135 deg.. That is, the densest pattern high in space utilization efficiency (especially in the direction of track width) can be realized.
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