eprintid: 201
rev_number: 4
eprint_status: archive
userid: 6
dir: disk0/00/00/02/01
datestamp: 2009-01-20
lastmod: 2015-05-29 19:49:17
status_changed: 2009-04-08 16:55:52
type: report
metadata_visibility: show
item_issues_count: 0
creators_name: Cooker, Mark
creators_name: Dellar, Paul
contributors_name: Lee, William
contributors_name: deFalco, Carlo
contributors_name: Barton, David
contributors_name: Farmer, Chris
contributors_name: Fowler, Andrew
contributors_name: King, John
contributors_name: Shishkin, G. I.
title: An Investigation into the Physics of Blowing Polysilicon Fuses
ispublished: pub
subjects: materials
subjects: other
studygroups: esgi62
companyname: Analog Devices
full_text_status: public
abstract: The semi-conductor fuses in this research are fabricated on a submicron process. A voltage potential is applied across the fuse, in order to achieve a blow. This current peaks with a short pulse in the order of tens of milliamps which has a long decrease to zero current flow, resulting in a blown fuse. A fuse blows due to the pinching together of electrically insulating material which initially surrounds the conducting pathway. The pinch cuts across the conductor, and so halts the current flow. In small-geometry fuses a cavity also forms during the blowing process.

The company wishes to understand the fuse blow process mathematically in order to develop a model that can accurately simulate the blowing of the fuses. This report records the thermal, electrical, solid and fluid mechanics of the blowing process that was discussed at the Study Group, with remarks on possible future research for modelling the process.
problem_statement: On silicon polysilicon fuses (OBPF) are a critical element for Integrated Circuits. OBPF allow high precision products to be calibrated in their final packaged solution or in the customers application. The long term reliability and stability of OBPF is of utmost importance in critical applications, such as, automotive, telecom networks etc. The polysilicon fuse is blown open with the application of a particular voltage, with success measured by a change in resistance. During characterisation an extensive Design of Experiments (voltage, time, external R/C, different Wafer Process conditions etc) is carried to find an optimum blow condition, ensuring maximum yield and reliability.

What is not understood is the physic of the opening of the polysilicon fuse. This could be influenced by:

- the material properties of polysilicon, which will change with process
technology and Wafer Fab equipment set
- the stress state of surrounding insulating oxides
- thermal gradients due to length / width of polysilicon, distance form substrate etc
- heating sinking of fuse tab’s, number of contacts etc
- thermal time constant of applied current pulse
- impact of peak current, duration, rise time on efficiency of fuse opening.

The aim of this project is to investigate and simulate the physic of opening a polysilicon fuse. The outcome would be a model that would allow a reduced DOE to release a new product with OBPF.
date: 2008
date_type: published
pages: 13
citation:   Cooker, Mark and Dellar, Paul  (2008) An Investigation into the Physics of Blowing Polysilicon Fuses.  [Study Group Report]     
document_url: http://miis.maths.ox.ac.uk/miis/201/1/analog-1.pdf