Study of Structure and Failure Mechanisms in ACA Interconnections Using SEM

Frisk, Laura

doi:10.5772/36965

Cited by 5 publications

(3 citation statements)

References 51 publications

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“…The high pressure is amplified for figure 9c) as the assembly shows a pressure spike due to nonplanarity in the bonding. Origins of a nonplanarity failure can range from production, bonding process, epoxy curing to humidity absorption [13]. For process self-planarization [14] as well reducing epoxy spill we attach polyimide tape on the backside of our substrates for the flip-chip bonding.…”

Section: Sphird Hybridisationmentioning

confidence: 99%

Pixel detector hybridisation and integration with anisotropic conductive adhesives

Volker,

Schmidt,

Dannheim

et al. 2024

J. Inst.

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A reliable and cost-effective interconnect technology is required for the development of hybrid pixel detectors. The interconnect technology needs to be adapted for the pitch and die sizes of the respective applications. This contribution presents recent results of a newly developed in-house single-die interconnection process based on Anisotropic Conductive Adhesives (ACA). The ACA interconnect technology replaces solder bumps with conductive micro-particles embedded in an epoxy layer applied as either film or paste. The electro-mechanical connection between the sensor and ASIC is achieved via thermocompression of the ACA using a flip-chip device bonder. The ACA technology can also be used for ASIC-PCB/FPC integration, replacing wire bonding or large-pitch solder bumping techniques. A specific pixel-pad topology is required to enable the connection via micro-particles and create cavities into which excess epoxy can flow. This pixel-pad topology is achieved with an in-house Electroless Nickel Immersion Gold (ENIG) process. The ENIG and ACA processes are qualified with a variety of different ASICs, sensors, and dedicated interconnect test structures, with pad diameters ranging from 12 μm to 140 μm and pitches between 20 μm and 1.3 mm. The produced assemblies are characterized electrically, with radioactive-source exposures, and in tests with high-momentum particle beams. This contribution introduces the developed interconnect and plating processes and showcases different hybrid assemblies produced and tested with the above-mentioned methods. A focus is placed on recent optimization of the plating and interconnect processes, resulting in an improved plating uniformity and interconnect yield.

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Section: Sphird Hybridisationmentioning

confidence: 99%

Pixel detector hybridisation and integration with anisotropic conductive adhesives

Volker,

Schmidt,

Dannheim

et al. 2024

J. Inst.

View full text Add to dashboard Cite

show abstract

“…The delamination will take place when the adhesion strength was lower than the vapor pressure level. Case study 3: Deformation [34][35][36][37][38] Deformation refers to the shape change or varies in size of an object.…”

Section: Mechanical and Thermomechanical Failure Modementioning

confidence: 99%

“…are bonded together, problems at interface ( Fig. 1-1) such as buckling [3] , cracking [4], formation of voids [5,6], adhesive fracture and delamination [7] may occur. Several factors such as high residual stress (external or internal), presence of contaminants, geometry concern or misfit in the coefficient of thermal expansion are always in the discussion to prevent bond failure.…”

Section: Introductionmentioning

confidence: 99%