Adhesive wafer bonding using partially cured benzocyclobutene for three-dimensional integration
2006 (English)In: Journal of the Electrochemical Society, ISSN 0013-4651, Vol. 153, no 4, G291-G295 p.Article in journal (Refereed) Published
Wafer-level three-dimensional integration (3D) is an emerging technology to increase the performance and functionality of integrated circuits (ICs), with adhesive wafer bonding a key step in one of the attractive technology platforms. In such an application, the dielectric adhesive layer needs to be very uniform, and precise wafer-to-wafer alignment accuracy (similar to 1 mu m) of the bonded wafers is required. In this paper we present a new adhesive wafer bonding process that involves partially curing (cross-linking) of the benzocyclobutene (BCB) coatings prior to bonding. The partially cured BCB layer essentially does not reflow during bonding, minimizing the impact of inhomogeneities in BCB reflow under compression and/or any shear forces at the bonding interface. The resultant nonuniformity of the BCB layer thickness after wafer bonding is less than 1% of the average layer thickness, and the wafers shift relative to each other during the wafer bonding process less than 1 mu m (average) for 200 mm diameter wafers. When bonding two silicon wafers using partially cured BCB, the critical adhesion energy is sufficiently high (>= 14 J/m(2)) for subsequent IC processing.
Place, publisher, year, edition, pages
2006. Vol. 153, no 4, G291-G295 p.
level, precision, mems
IdentifiersURN: urn:nbn:se:kth:diva-15485DOI: 10.1149/1.2168409ISI: 000235723600049OAI: oai:DiVA.org:kth-15485DiVA: diva2:333526
QC 201005252010-08-052010-08-05Bibliographically approved