Y.C.P. Carisey

Bio: Y.C.P. Carisey is an academic researcher from Delft University of Technology. The author has contributed to research in topics: Copper & Nanoparticle. The author has an hindex of 2, co-authored 2 publications receiving 8 citations.

3D interconnect technology based on low temperature copper nanoparticle sintering

Abstract: We explore a methodology for patterned copper nanoparticle paste for 3D interconnect applications in wafer to wafer (W2W) bonding. A novel fine pitch thermal compression bonding process (sintering) with coated copper nanoparticle paste was developed. Most of the particle size is between 10–30 nm. Lithographically defined stencil printing using photoresist and lift-off was used to apply and pattern the paste. Variations in sintering process parameters, such as: pressure, geometry and ambient atmosphere, were studied. Compared to Sn-Ag-Cu (SAC) microsolder bumps, we achieved better interconnect resistivity after sintering at 260 °C for 10 min, in a 700 mBar hydrogen forming gas (H 2 /N 2 ) environment. The electrical resistivity was 7.84 ± 1.45 µΩ·cm, which is about 4.6 times that of bulk copper. In addition, metallic nanoparticle interconnect porosity can influence the electrical properties of the interconnect. Consequently, we investigated the porosity effect on conductivity using finite element simulation. A linear relationship between the equivalent conductivity and particle overlapping ratio was found.

Metallic Nanoparticle Based Interconnect for Heterogeneous 3D Integration

Abstract: We explored the properties and performance of copper-based metallic nanoparticle paste (MNPs) for interconnects applications in 3D heterogeneous integration. A patterning method was developed to process micron sized sintered MNPs structures. This enables the fabrication of IC interconnect test structures to characterise specific resistivity sintered MNPs and the contact resistances of sintered MNP to bulk copper (bCu) which was respectively 78.4 mOhm.micrometer and 0.23 Ohm.micrometer2. In situ XRD analysis showed no oxidation of MNPs at processing temperatures below 100 oC. When Copper based MNPs are sintered under forming gas conditions, no oxidation of copper is measured. With in situ TEM at a temperature range of 220 -- 260 oC local melting of copper nanoparticles was observed. This is in agreement with the electrical measurements, the resistivity and contact resistance are considerably reduced when MNPs is sintered in this temperature range. Copper-based MNPs is successfully applied as die attach and wafer to wafer (W2W) bonding. However, for W2W bonding, the specific contact resistance was 800 Ohm.micrometer2.

Nanopackaging: Nanotechnologies and Electronics Packaging

Abstract: Nanotechnologies are being applied to microelectronics packaging, primarily in the applications of nanoparticle nanocomposites, or in the exploitation of the superior mechanical, electrical, or thermal properties of carbon nanotubes. Composite materials are studied for high-k dielectrics, electrically conductive adhesives, conductive "inks," underfill fillers, and solder enhancement. These trends are demonstrated by paper presentations over the past few years at ECTC and other conferences, which show research to be concentrated in relatively few laboratories, with little work being done on the packaging requirements of the new nanoelectronics technologies. Future needs (predictably) include education and software development

Low-temperature, organics-free sintering of nanoporous copper for reliable, high-temperature and high-power die-attach interconnections

Abstract: A novel die-attach joining technique based on low-temperature film sintering of nanoporous Cu is demonstrated Nanoporous Cu films are proposed as a low-cost replacement of nano-sintering pastes with the following benefits: (i) synthesis by electrochemical dealloying, compatible with standard lithography processes; (ii) no organic content to minimize risks of voiding and corrosion; and (iii) controllable physical properties post sintering through tailorable initial nanostructure and morphology As a first proof-of-concept, thin films of nanoporous Cu with 25–50nm feature size and ∼60% relative density were synthesized by dealloying of Cu-Si films The nanoporous Cu films were then sintered on bulk Cu metallizations at temperatures of 200–250°C for 5–15min with an applied pressure of 6–9MPa, in reducing atmosphere A maximum shear strength of 42kgf was achieved and analysis of the fracture profiles showed failure through the sintered joints, confirming strong metallurgical bonding to bulk Cu Cross-sections of joints formed at 200°C and 250°C −15min observed by SEM showed relative density as high as 85%, achieved for the first time with sintered copper

A Cu-Cu Bonding Method Using Preoxidized Cu Microparticles under Formic Acid Atmosphere

Abstract: Many power semiconductor devices now require high tolerance of current density and reliability at high temperature, therefore Cu-Cu bonding using an insert material has raised the level of concerns for its great thermal stability and conductivity. In this study, a low-pressure bonding process was developed to achieve a Cu-Cu bonding using preoxidized Cu microparticles under formic acid atmosphere. The Cu microparticles were preoxidized to generate oxide films and Cu oxide nanostructures, which were then reduced and bonded at 300 °C under formic acid atmosphere to achieve a Cu-Cu bonding. Shear strength of the Cu-Cu bondings were tested to optimize the parameters of bonding process. Fracture surfaces of the Cu-Cu bonding, as well as cross-sectional microstructures, were observed by scanning electrical microscope (SEM) and components were identified by X-ray diffraction (XRD) to investigate the bonding mechanism. The findings reveal that the oxide films and the nanostructures play key roles in this reduction bonding process, which is a promising method to obtain a Cu-Cu bonding satisfying the requirements of power device packaging.