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Polysilicon Strap Process for Fuses

IP.com Disclosure Number: IPCOM000102864D
Original Publication Date: 1990-Mar-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 1 page(s) / 43K

Publishing Venue

IBM

Related People

Cronin, JE: AUTHOR [+3]

Abstract

In a device process wherein doped polysilicon is used to form a connective strap from a trench to a nearby device structure, e.g., a diffusion, fuses and resistors may be formed during the strap deposition and definition process. Benefits of self-passivation and lack of conductive material splatter after blowing polysilicon fuses are derived. Since the conductive strap has wide conductivity tolerance, the polysilicon thickness and doping level may be tailored to optimize fuse blowing and/or to make resistors of desired values.

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Polysilicon Strap Process for Fuses

      In a device process wherein doped polysilicon is used to form a
connective strap from a trench to a nearby device structure, e.g., a
diffusion, fuses and resistors may be formed during the strap
deposition and definition process. Benefits of self-passivation and
lack of conductive material splatter after blowing polysilicon fuses
are derived.  Since the conductive strap has wide conductivity
tolerance, the polysilicon thickness and doping level may be tailored
to optimize fuse blowing and/or to make resistors of desired values.

      Referring to the figure, the same masking level and processing
used to define polysilicon trench straps is also used to create P+
polysilicon fuse or resistor 2 in oxide 4 over oxide 6 on silicon
substrate 8.  Thin oxide 10, which covers polysilicon 2, has a very
uniform thickness at all points on a wafer.  At the process step
wherein borderless contacts are made to diffusions, tungsten contacts
12 may be made to ends of fuse 2.

      Laser blowing of such fuses has wide process tolerance due to
the well-defined thickness of polysilicon 2 and oxide 10.  This type
of fuse structure may be blown electrically, if desired.  Blown fuses
are self-passivating and provide no problem with conductive debris.

      Disclosed anonymously.