Browse Prior Art Database

Process and Structure for Laser Fuse Blowing

IP.com Disclosure Number: IPCOM000034913D
Original Publication Date: 1989-May-01
Included in the Prior Art Database: 2005-Jan-27
Document File: 2 page(s) / 31K

Publishing Venue

IBM

Related People

Chesebro, DG: AUTHOR [+3]

Abstract

By placing an etch stop layer over fuse sites soon after fuses are defined, fuse blowing is performed through a well controlled, thin insulating layer, after most of overlying insulating material is removed. Referring to the figure, by standard processing fuses 2 are deposited and defined over insulating layer 4 and covered by reflowable glass layer 6. During usual definition of refractory metal M1 for first level circuitry, a region over the fuses is left covered by M1 by altering the M1 mask. This M1 region subsequently is used as an etch stop. Normal processing is then used to deposit oxide layer 8. Next, second level circuitry M2 is deposited and defined by standard processing. When M2 is an Al-based material, no further etch stop material is required over M2 for this process.

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Process and Structure for Laser Fuse Blowing

By placing an etch stop layer over fuse sites soon after fuses are defined, fuse blowing is performed through a well controlled, thin insulating layer, after most of overlying insulating material is removed. Referring to the figure, by standard processing fuses 2 are deposited and defined over insulating layer 4 and covered by reflowable glass layer 6. During usual definition of refractory metal M1 for first level circuitry, a region over the fuses is left covered by M1 by altering the M1 mask. This M1 region subsequently is used as an etch stop. Normal processing is then used to deposit oxide layer 8. Next, second level circuitry M2 is deposited and defined by standard processing. When M2 is an Al-based material, no further etch stop material is required over M2 for this process. Usual conformal layers of oxide 10, nitride 12, and polyimide are then applied. Terminal via hole opening masks are altered to expose not only terminal pads, e.g., at hole A, but also the fuse area in hole B. The last etch step in normal etch processing to open hole A to M2 is extended to etch through layer 8. M1 material in hole B acts as an etch stop. M1 is then selectively etched away and photoresist is removed to leave the structure shown in the figure. Fuse blowing is then performed during pad probe testing by a laser beam having to penetrate only glass 6 coverage of fuses 2. Broadly, an etch stop layer is provided over a fuse region aft...