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Highly Sensitive Electrical Shorting Monitor for BEOL Semiconductor Fabrication

IP.com Disclosure Number: IPCOM000243970D
Publication Date: 2015-Nov-02
Document File: 1 page(s) / 65K

Publishing Venue

The IP.com Prior Art Database

Abstract

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Title

Highly Sensitive Electrical Shorting Monitor for BEOL Semiconductor Fabrication

Abstract

Disclosed is a method to increase sensitivity to Back End of Line Inter Layer Dielectric (BEOL ILD) films, integration, or etch variability for metal shorts.

Problem

A method is needed for detecting metal-to-metal line shorting in Back End of Line (BEOL) semiconductor fabrication in advanced technology nodes with small wire pitches and dimensions, as well as in analog/mixed signal technologies with varying geometry devices, wire pitches, and features (small and large features.)

Current solutions add a Tungsten or refractory metal layer underneath a subtractive metal line stack. The sensitivity to removing the tungsten layer substantially increases.

Solution/Novel Contribution

The novel contribution is a method and a structure to detect inconsistencies or stack up tolerance issues with fail modes.

Method/Process

The structure has a thin Tungsten or other refractory metal as part of the subtractive metal stack in a kerf comb structure. The Tungsten is on the bottom of the stack. The Tungsten is etched in a subtractive metal etcher along with the Ti-Nitride, Aluminum, and Titanium. As the last metal to be etched and the most challenging, the metal remains unless the etch perfectly removes the Tungsten.

The process can be driven by a poor or non-uniform etch either by varying underlying Chemical Mechanical Planarization (CMP) or oxide/level topography or by varying oxide o...