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Masterslice Concept for Multiple Chip Sizes

IP.com Disclosure Number: IPCOM000076895D
Original Publication Date: 1972-May-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Tsui, F: AUTHOR

Abstract

Due to temperature changes, pads placed at the periphery of a semiconductor chip are subjected to mechanical stresses, which are higher the larger the chip size and which are often the cause of failures. This problem is minimized by having the pads in the central area of the chip.

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Masterslice Concept for Multiple Chip Sizes

Due to temperature changes, pads placed at the periphery of a semiconductor chip are subjected to mechanical stresses, which are higher the larger the chip size and which are often the cause of failures. This problem is minimized by having the pads in the central area of the chip.

For a chip with central pads, the chip size is chosen solely according to its circuit requirements. Since chips of different sizes and designed for different functions generally use the same basic devices for their circuits, a single masterslice arrangement with a common set of a maximum number of pads is used for a great number of different chip types. For all process steps, except the metallization step, a set of basic masks is used based on a layout comprising a regularly patterned assembly of basic devices. Circuits for input/output powering and encoding/decoding purposes are provided in the area between and under the pads.

For making the actual masks for a chip smaller than the standard maximum size, the technique of combinational overlaying of masks is used. For each individual chip size, only one additional framing mask is needed, which is used to limit the basic layout to the desired size and to cover up all the unwanted devices in the oversize areas.

Placing the pads near the center of the chip improves the wirability of the chip, since additional areas can be freely used, if necessary, at the periphery of the chip to accommodate more...