Pattern dependent corrosion in hybrid bonding and discharge measurement to define root cause of the corrosion

Hybrid Bonding has emerged as a promising technology for advanced 3D integration, offering superior electrical and thermal performance, as well as fine pitch interconnection. While hybrid bonding offers significant advantages over traditional micro-bumps for increasing interconnect densities and enabling pitch scaling, further scaling presents challenges. Topography and chemistry control of the Cu/dielectric surface, issues like the presence of particles leading to bonding failures, and wafer/die alignment accuracy are areas actively addressed by both companies and research institutions. 

One of the purposes of this internship project is to understand the underlying mechanisms in the different steps of the process module critical to achieving a successful hybrid bonding result. Specifically, pattern-dependent corrosion of Cu pads on the bonding surface is a significant threat to precise hybrid bonding, especially as the pad critical dimension (CD) decreases. So far, pattern-dependent corrosion hasn't been widely recognized as a major challenge compared to other risks like contamination from singulation or pick-and-place accuracy. However, this corrosion will pose a significant challenge for scaling hybrid bonding, becoming more severe as the pad CD decreases, posing a risk particularly for pad CD values under 200 nm. 

This internship project will focus on identifying specific CMP parameters that induce pattern-dependent corrosion. This will involve systematically varying key CMP process parameters at coupon scale on an experimental CMP tool, such as slurry composition (e.g. pH, abrasive, inhibitor), downforce, platen speed, and polishing time. Also, accumulated charge during process is expected to be a primary cause of pattern-dependent corrosion. Therefore, project will involve using a novel methodology to measure electrical discharge from hybrid bonding pads, especially from structures smaller than 1 µm. The intern will learn to operate a wafer probe station and oscilloscope to record current discharge from the hybrid bonding pads.

Type of Project: Combination of internship and thesis

Master's degree: Master of Science; Master of Engineering Science

Master program: Chemistry/Chemical Engineering; Materials Engineering; Nanoscience & Nanotechnology; Physics

Duration: up to 1 year

Supervisor: Stefan De Gendt (Chemistry, Nano)

For more information or application, please contact the supervising scientists Sung Woo Park (sung.woo.park.ext@imec.be), Harold Philipsen (harold.philipsen@imec.be) and Stefan De Gendt (stefan.degendt@imec.be).

Only for self-supporting students.