Fundamentals of Wafer Bonding for SOI: From Physical Mechanisms Towards Advanced Modeling

Abstract

The wafer bonding has been established as a key process used for the fabrication of silicon-on-insulator (SOI) substrates. In the present paper an overview of the fundamental aspects involved in the wafer bonding process is presented. The mechanisms of the silicon and silicon oxide bonding are discussed with an emphasis on the phenomenological models developed in case of SOI bonding. Interactions between the mechanical adhesion and the dynamics of the interface chemistry and their impact on the bonding modeling are also discussed. One of the main challenges today is the validation of existing models and the comparison of physical measurements with the advanced modeling results.

Fabrication and characterization of silicon-on-insulator wafers

“…The thinning down for the formation of the device layer is achieved through grinding, wet or dry chemical processes [55]. The BSOI method is predominantly employed to fabricate device layers with a thickness between 10 to 100 µ m [56]. However, it presented a deterioration in uniformity when utilized for the fabrication of thinner device layers.…”

(Invited) In Memoriam Ulrich Gösele: Wafer Bonding à la Carte

“…Figure 1. Schematic of bonding simulation approach: ability to bond and reliability of the system with respect to temperature and time [10]. While the schemes to predict relevant information about bonded wafer pairs can be drafted, the current challenge is the comparison to physical measurements.…”

“…An alternative is the bond-and-etch back SOI (BESOI) process, in which an etch stop is introduced in advance, before wafer bonding. Recently, we reported on advanced modelling approaches that are related to SOI bonding [10]. The predictive modelling of bonding is driven by the following questions: can two wafers be bonded and later how the bonding interface will strengthen with annealing.…”

“…Figure 1. Schematic of bonding simulation approach: ability to bond and reliability of the system with respect to temperature and time [10].…”

Wafer-scale detachable monocrystalline germanium nanomembranes for the growth of III–V materials and substrate reuse

“…14,15 In recent years, various strategies for fabrication of detachable membranes and substrate reuse have been proposed. For example, the Smart-Cut™ process 16,17 pioneered the fabrication of NMs on oxide substrates, using ion implantation to create a separation interface in the parent substrate, and wafer bonding to transfer the layer on the inexpensive substrate holder. Another technique called Epitaxial li-off of layers (ELO) uses a sacricial layer with selective chemical etching to grow and release the "active" epitaxial structure.…”