Adhesive bonding in microelectronics and photonics

Abstract

The use of adhesive bonding in joining of materials with different characteristics is of major importance in a variety of microelectronic and photonic applications. The curing of such adhesives is also of great consequence, with the use of optical radiation for adhesive curing becoming the method of choice in various applications, especially bonding of components in microelectronics and fiber-optic assembly. This article reviews recent advances in the development of adhesives, their applications, and their curing methods using optical radiation; it also includes a brief overview of the adhesion mechanisms.

Joining of dissimilar materials

“…Specific surfaces, various mechanisms and/or their combinations may be engaged in the bonding process. Bond formation results in a contact zone (intermediary zone) created between the adherent and adhesive [284]. Adhesive should completely wet the bonding area, but material surfaces will be irregular and voids may occur.…”

“…Adhesive should completely wet the bonding area, but material surfaces will be irregular and voids may occur. The adhesive composition and the contact zone determine the bond characteristics, viscosity of adhesive and surface energy of the substrate [284].…”

“…Adhesives have become widely used in different industry sectors, especially in electronics [286]. For example, adhesive bonding is used in the fibre to glass ferrule attachment in fibre optics manufacturing [284].…”

“…Advantages of adhesive bonding are: (i) creation of a continuous bond, (ii) corrosion prevention (sealed joint), (iii) stress distribution over a joint area, (iv) vibration reduction, (v) invisibility of joints within assembly, (vi) minimization of an assembly mass, (vii) no substrate deformation and (vii) minimizations of components in an assembly (Niagu et al [179]; Small and Courtney [224]; Yacobi et al [284]). …”

Spectral-domain optical coherence tomography on a silicon chip

“…Ismail et al have proposed a SiON-compatible microlens fabrication technique which will eliminate the need for bulky lenses in the current configuration [Ism12]. For the integration of active component, wafer bonding techniques have been widely used to demonstrate high performance hybrid platforms and its higher flexibility is more preferable compared to monolithic integration due to the large mismatch in lattice and thermal expansion coefficient between passive and active materials [Yac02]. One possible approach for realizing an integrated light source could be directing the emitted light from active region using 45 o turning mirrors towards the passive layer which is bonded to the active layer by using the wafer bonding techniques described elsewhere [Roe06,Roe08].…”