Browse Prior Art Database

Direct Write EC Scheme

IP.com Disclosure Number: IPCOM000039631D
Original Publication Date: 1987-Jul-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 2 page(s) / 74K

Publishing Venue

IBM

Related People

Lussow, RO: AUTHOR [+3]

Abstract

A method has been proposed which will provide engineering change (EC) capability to a semiconductor module without requiring the addition of new wires. It provides greater chip density to the device since no EC pads are required on the surface. In the production of packaging devices it has been a practice to include EC pads on the surface which may be used for making subsequent changes. In this proposal, three additional green sheets are added to the module which are designated as EC layers No. 1,2, and 3 (Fig. 1A). Vias are punched in the EC layers to permit both the LST via 4 and the power via 5 to go through the layers from the chip 6. Dielectric pads 7 (Fig. 1B) are inserted to electrically isolate selected vias 4, as may be required.

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Direct Write EC Scheme

A method has been proposed which will provide engineering change (EC) capability to a semiconductor module without requiring the addition of new wires. It provides greater chip density to the device since no EC pads are required on the surface. In the production of packaging devices it has been a practice to include EC pads on the surface which may be used for making subsequent changes. In this proposal, three additional green sheets are added to the module which are designated as EC layers No. 1,2, and 3 (Fig. 1A). Vias are punched in the EC layers to permit both the LST via 4 and the power via 5 to go through the layers from the chip 6. Dielectric pads 7 (Fig. 1B) are inserted to electrically isolate selected vias 4, as may be required.

(Image Omitted)

The sheets all have vias with the first having an horizontal preprint master line pattern (Fig. 2A) and the third having a vertical preprint master line pattern (Fig. 2C). The sheets are tailored by direct write techniques so that the lines are connected to vias to achieve the desired changes. A typical change illustrated in Fig. 2B shows a direct write pattern on EC2 layer 2 to LST via 4 to horizontal 10 and vertical lines 9.

(Image Omitted)

The basic function of the EC2 layer is to improve the local wirability of EC1 and EC3. Without the EC2 layer, each LST via can only be connected to two adjacent horizontal and two vertical lines. With the EC2 layer, the number of lines is unlimited. Fi...