AVS 51st International Symposium
    Surface Science Thursday Sessions
       Session SS2-ThM

Paper SS2-ThM2
Advanced Adhesion Test Methods for Semiconductor Interconnect Film

Thursday, November 18, 2004, 8:40 am, Room 210C

Session: Tribology, Adhesion, and Friction
Presenter: A.K. Sikder, Center for Tribology, Inc.
Authors: A.K. Sikder, Center for Tribology, Inc.
N. Gitis, Center for Tribology, Inc.
M. Vinogradov, Center for Tribology, Inc.
Correspondent: Click to Email
For faster signal propagation in integrated circuits, new materials with lower dielectric constant (low-k) values are required with copper metal lines. Low-k materials possess many challenges due to their poor mechanical integrity and weak adhesion to other interconnects, so it is important to characterize their adhesion behavior. There are numerous techniques known for adhesion and delamination testing of coatings, some of the most common being a tape test, stud-pull test, scratch test and an indentation test. Each of them has its advantages, but neither one is universally effective for soft to hard, ultra-thin to thick films. The new testing technology, based on multiple sensors coupled with servo-control of forces and displacements, has been developed to fill this void. A novel technology for scratch testing has been developed in order to evaluate the tribo-mechanical behavior of interconnect thin films, where an indenter moves in both vertical (loading) and horizontal (sliding) directions, while acoustic emission and electrical resistance sensors allow for detection of the initiation of fracture, and the scratch pattern indicates the type of failure. The impression left by scratch testing is then observed using scanning probe and optical microscopy, integrated into the instrument mod. UNMT. Scratch testing on various interconnect blanket and patterned, single and multilayered, polished and unpolished film is presented. Adhesion and delamination characteristics are discussed with respect to the intrinsic properties of the different interconnect films (low-k, copper and tantalum) and their surface roughness. Their effective testing in the stack of the films is complimented by frictional and acoustic measurements. The multi-sensing technology allowed for comprehensive characterization of the scratch, adhesion and durability of thin coatings.