Cu Pillar Planarization to Enhance Thermosonic Flipchip Bonding

Roshanghias, Ali; Rodrigues, Augusto; Kaczynski, Jaroslaw; Binder, Alfred; Schmidt, Andreas B.

doi:10.23919/empc53418.2021.9584966

Cited by 4 publications

(1 citation statement)

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“…The proposed planarization process led to an increase of up to 60% in the contact area. 15 Nonetheless, these studies were conducted on Cu pillars with a diameter of 100 μm and a large pitch size of 350 μm which are not categorized in the ultra-fine pitch class. In another study by Bajwa et al, ultrafine pitch (10 μm) bonding of Cu pads was carried out.…”

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confidence: 99%

3D Integration via D2D Bump-Less Cu Bonding with Protruded and Recessed Topographies

Roshanghias

Kaczynski

Rodrigues

et al. 2023

ECS J. Solid State Sci. Technol.

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Bump-less copper (Cu) bonding is currently the most attractive approach for fine-pitch (< 20 µm) 3D integration due to its compatibility with the wafer back-end-of-the-line fabrication process. In this study, themocompression bonding of bump-less Cu pads with a diameter of 4 µm and a pitch size of 10 µm was pursued, while chemical mechanical polishing (CMP)-processed Cu pads enclosed in SiO2 were employed with both protruded and recessed topographies. The effects of Cu topography (protruded or recessed) and bonding temperature on the electrical and microstructural properties of the die bonds as well as mechanical bonding strength were investigated. It was found that thermocompression bonding of CMP-processed Cu can be realized at shorter processing times, lower bonding temperatures, and pressures than standard electroplated Cu bonding. The bonding yield of the three configurations, i.e. protruded-protruded, protruded-recessed, and recessed-recessed Cu pads was also compared.

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confidence: 99%