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Element Trimming Fusible Link

IP.com Disclosure Number: IPCOM000041465D
Original Publication Date: 1984-Jan-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Nickel, DJ: AUTHOR

Abstract

A fusible link 10 is provided for trimming resistors or capacitors. Polysilicon fuses 12, 14, 16, 18 and 20 of different widths are provided on a chip so that they can be selectively opened with only a two-wire connection scheme. As shown in the figure, pads 1 and 2 have metal lines 22 and 24 connected to opposite ends of each of the fuses 12, 14, 16, 18 and 20. By using, e.g., a tester-generated current pulse which is proportional to the desired resistance, a selected fuse 12, 14, 16, 18 or 20 may be opened. Thus, if the resistance from A to C is desired, an open would be made in fuse 12. However, if a larger resistance is desired, e.g., from A to E, an open would be formed in fuse 16. Elements A through F could be made from lightly doped polysilicon or diffusion in the bulk silicon.

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Element Trimming Fusible Link

A fusible link 10 is provided for trimming resistors or capacitors. Polysilicon fuses 12, 14, 16, 18 and 20 of different widths are provided on a chip so that they can be selectively opened with only a two-wire connection scheme. As shown in the figure, pads 1 and 2 have metal lines 22 and 24 connected to opposite ends of each of the fuses 12, 14, 16, 18 and 20. By using, e.g., a tester-generated current pulse which is proportional to the desired resistance, a selected fuse 12, 14, 16, 18 or 20 may be opened. Thus, if the resistance from A to C is desired, an open would be made in fuse 12. However, if a larger resistance is desired, e.g., from A to E, an open would be formed in fuse 16. Elements A through F could be made from lightly doped polysilicon or diffusion in the bulk silicon. A through F could also be a plurality of capacitors connected from points B through F to the common node A in a parallel arrangement. A trimmable capacitor would then be formed between pad 1 and/or pad 2 and the common node A. The capacitance resulting from trimming would be inversely proportional to the current pulse from the tester. It can be seen that the energy of the current pulse is adjusted such that the desired thin fuse or line, along with all thinner fuses or lines, is blown.

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