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Addition of Boron to Low-K Dielectrics to Increase Mechanical Integrity while Lowering K-Effective

IP.com Disclosure Number: IPCOM000020747D
Original Publication Date: 2003-Dec-11
Included in the Prior Art Database: 2003-Dec-11
Document File: 1 page(s) / 59K

Publishing Venue

IBM

Abstract

The inclusion of boron into the low-k dielectric, such as SiCOH, will form desired B-C, B-N and B-O bonds, which are stronger than the corresponding Si-based bonds.

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Addition of Boron to Low-K Dielectrics to Increase Mechanical Integrity while Lowering K-Effective

The inclusion of boron into the low-k dielectric, such as SiCOH, will form desired B-C, B-N and B-O bonds, which are stronger than the corresponding Si bonds. One problem that can arise is the strong hygroscopic nature of borosilicate glasses. This can be circumvented in BEOL integration in similar manner to how other water-absorbing materials such as many organic polymers are integrated. To wit, one takes precautions to always bake out the layers prior to capping, and one builds in redundant layers and metal structures to seal the innards of the chip against ingress of environmental components such as moisture.

Use of boron to dope low-k dielectrics, such as SiCOH, is disclosed. PEVCD method includes an organoslicate precursor such as a cyclic organosiloxane, trimethyl borate or boron bunyldimethyl siloxide (for B-O bonds) and a carrier gas such as He or CO2. Alternatively, other boron-containing molecules such as borazine, diborane, triphenyl borane (for B-C bonds), etc., may be used. In addition to homogeneous addition of boron bonds to the film, a boron-rich layer at top or bottom could serve as an adhesion promoter, given that carbon-rich surfaces tend not to be strong adhesion interfaces. Structures containing this film are also disclosed, such as Cu damascene and dual-damascene multilevel on-chip interconnects embedded in boron-containing low-k SiCOH with k <...