Fine-pitch bump-less Cu-Cu bonding for wafer-on-wafer stacking and its quality enhancement

2010 ◽  
Author(s):  
L. Peng ◽  
H. Y. Li ◽  
D. F. Lim ◽  
R. I. Made ◽  
G. Q. Lo ◽  
...  
Keyword(s):  
Quality Enhancement ◽  
Fine Pitch ◽  
Cu Bonding

scholarly journals The Effect of an Ag Nanofilm on Low-Temperature Cu/Ag-Ag/Cu Chip Bonding in Air

2021 ◽  
Vol 11 (20) ◽  
pp. 9444
Author(s):  
Yoonho Kim ◽  
Seungmin Park ◽  
Sarah Eunkyung Kim
Keyword(s):  
Low Temperature ◽  
High Performance ◽  
Bonding Process ◽  
Bonding Interface ◽  
Fine Pitch ◽  
Bonding Technology ◽  
Cu Bonding ◽  
Cu Oxidation ◽  
Pure Cu

Low-temperature Cu-Cu bonding technology plays a key role in high-density and high-performance 3D interconnects. Despite the advantages of good electrical and thermal conductivity and the potential for fine pitch patterns, Cu bonding is vulnerable to oxidation and the high temperature of the bonding process. In this study, chip-level Cu bonding using an Ag nanofilm at 150 °C and 180 °C was studied in air, and the effect of the Ag nanofilm was investigated. A 15-nm Ag nanofilm prevented Cu oxidation prior to the Cu bonding process in air. In the bonding process, Cu diffused rapidly to the bonding interface and pure Cu-Cu bonding occurred. However, some Ag was observed at the bonding interface due to the short bonding time of 30 min in the absence of annealing. The shear strength of the Cu/Ag-Ag/Cu bonding interface was measured to be about 23.27 MPa, with some Ag remaining at the interface. This study demonstrated the good bonding quality of Cu bonding using an Ag nanofilm at 150 °C.

Ultra-fine pitch Cu-Cu bonding of 6μm bump pitch for 2.5D application

2016 ◽  
Author(s):  
Ser Choong Chong ◽  
Ling Xie ◽  
Sunil Wickramanayaka ◽  
Vasarla Nagendra Sekhar ◽  
Daniel Ismael Cereno
Keyword(s):  
Fine Pitch ◽  
Cu Bonding

scholarly journals Technical Barriers and Development of Cu Wirebonding in Nanoelectronics Device Packaging

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
C. L. Gan ◽  
E. K. Ng ◽  
B. L. Chan ◽  
U. Hashim ◽  
F. C. Classe
Keyword(s):  
Success Factors ◽  
Bonding Parameters ◽  
Green Mold ◽  
Fine Pitch ◽  
Bga Package ◽  
Bond Interface ◽  
Ball Bonds ◽  
Cu Bonding ◽  
Reliability Performance ◽  
Intermetal Dielectric

Bondpad cratering, Cu ball bond interface corrosion, IMD (intermetal dielectric) cracking, and uncontrolled post-wirebond staging are the key technical barriers in Cu wire development. This paper discusses the UHAST (unbiased HAST) reliability performance of Cu wire used in fine-pitch BGA package. In-depth failure analysis has been carried out to identify the failure mechanism under various assembly conditions. Obviously green mold compound, low-halogen substrate, optimized Cu bonding parameters, assembly staging time after wirebonding, and anneal baking after wirebonding are key success factors for Cu wire development in nanoelectronic packaging. Failure mechanisms of Cu ball bonds after UHAST test and CuAl IMC failure characteristics have been proposed and discussed in this paper.

Comparison of Enabling Wafer Bonding Techniques for TSV Integration

2010 ◽  
Author(s):  
Bioh Kim ◽  
Thorsten Matthias ◽  
Markus Wimplinger ◽  
Paul Kettner ◽  
Paul Lindner
Keyword(s):  
Adhesive Bonding ◽  
Silicon Oxide ◽  
Bonding Temperature ◽  
Transient Liquid Phase ◽  
Alignment Accuracy ◽  
Process Time ◽  
Covalent Bonds ◽  
3D Ics ◽  
Fine Pitch ◽  
Cu Bonding

In this study are compared the technical merits and demerits of three bonding methods suitable for manufacturing 3D-ICs. Patterned metal thermo-compression bonding facilitates fine-pitch, high-density TSV stacking with lower electrical resistance and higher mechanical strength. Direct Cu-Cu bonding is preferred over transient liquid phase bonding with Sn or Sn alloys, but reliable Cu-Cu bonds result only from high process temperature and long process time. Both bonding temperature and post-bond annealing temperature have the most significant influence on Cu-Cu bond properties. The pre-bonding of silicon oxide bonds occurs at room temperature and thus does not induce any run-out errors in wafer alignment, resulting in higher post-bond alignment accuracy. Subsequent heating to high temperatures is necessary to achieve covalent bonds, but modifying the surface chemistry by plasma activation allows the formation of strong chemical bonds at significantly lower annealing temperatures (200–400°C). Adhesive bonding has such advantages as low bonding temperature and process time compared to metal bonding, the tolerance to wafer topography and surface conditions, and the ability to join any wafer materials. However, the material reflow imposes some challenges for maintaining the alignment accuracy and another major concern is the reliability of polymer adhesives during the post-bond processes.

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