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Temperature Cycling to Delineate Plastic Zones at Metallization Cracks

IP.com Disclosure Number: IPCOM000119614D
Original Publication Date: 1991-Feb-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 2 page(s) / 53K

Publishing Venue

IBM

Related People

Coles, LS: AUTHOR [+3]

Abstract

Determining the configuration of highly strained areas (plastic zones) in the vicinity of cracks in integrated circuit metallization is accomplished by temperature cycling, which etches voids in the metal in the plastic zones.

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Temperature Cycling to Delineate Plastic Zones at Metallization Cracks

      Determining the configuration of highly strained areas
(plastic zones) in the vicinity of cracks in integrated circuit
metallization is accomplished by temperature cycling, which etches
voids in the metal in the plastic zones.

      Study of metallization failure on semiconductor products has
shown that thermal fatigue (temperature cycling) induces creep-type
metal migration, a mechanism that causes the plastic zones in
deformed metal to become void of metal without disturbing the
surrounding structures.  This has the effect of allowing a person to
"see" the plastic zone, once the metal has been removed.

      The process determines metal properties and defines a basic
fracture cell concept for this film metallization, independent of
manufacturing process.  The methodology allows the person to
determine properties when the metal is plastically deformed,
circumventing property change due to removal of covering layers.  The
methodology also allows a more accurate interpretation of reliability
studies by allowing subtraction of the mechanical interaction from
the thermal effects and allows an understanding of stress-related
failure mechanisms.

      Figs. 1 and 2 show an integrated circuit metallization 1 with a
crack 2 respectively, before and after temperature cycling to
delineate the plastic zone 3 in the vicinity of a known or suspected
crack 2.  The very large-scale integra...