Title :
Thermomechanical and electrochemical reliability of fine-pitch through-package-copper vias (TPV) in thin glass interposers and packages
Author :
Demir, Kubilay ; Ramachandran, Kishore ; Sato, Yuuki ; Qiao Chen ; Sukumaran, Vijay ; Pucha, Raghuram ; Sundaram, Venky ; Tummala, Rao
Author_Institution :
3D Syst. Packaging Res. Center, Georgia Inst. of Technol., Atlanta, GA, USA
Abstract :
This paper reports reliability of copper-plated through-package-vias (TPVs) in glass interposer by modeling and experimental validation using accelerated life tests. In this paper, both thermomechanical reliability and electrochemical reliability of fine-pitch TPVs in glass interposer were investigated. Thermomechanical reliability was investigated by developing finite element models to calculate the thermomechanical stresses and strains inside TPVs during thermal cycling tests with several glass and polymer liner combinations. Fatigue lifetime of TPVs in glass is predicted based on these simulation results and then validated using experiments. Test samples with daisy chains of TPVs are fabricated with different glass and polymer material combinations and subjected to accelerated temperature cycling tests to assess the thermomechanical reliability of TPVs in glass interposer. Resistance of each daisy chain is monitored using 4-point probe during cycling. It is observed that majority of test samples passed 1000 thermal cycles without any significant changes in electrical resistance. Cross-sectioning of TPV daisy chains that showed significant changes in resistance, revealed that failures were related to defects induced during copper plating in TPV side walls. Electrochemical migration reliability of TPVs in glass was investigated to study conductive anodic filament (CAF) resistance of glass at very small via spacing. Test samples with different material combinations were subjected to biased and highly accelerated stress temperature-humidity test (HAST) to assess electrochemical migration reliability of TPVs. After biased-HAST for 100 hours at 130°C, 85% relative humidity (RH) and 5 V DC, no CAF failures were detected in either of the two material combinations, indicating good insulation reliability under high temperature and humidity conditions.
Keywords :
copper; finite element analysis; glass; humidity; integrated circuit packaging; integrated circuit reliability; life testing; 4-point probe; CAF resistance; FEM; HAST; RH; TPV; accelerated life tests; accelerated temperature cycling tests; conductive anodic filament resistance; copper plating; copper-plated through-package-vias; cross-sectioning; daisy chains; electrochemical migration reliability; fine-pitch through-package-copper vias; finite element models; glass combinations; highly accelerated stress temperature-humidity test; humidity conditions; insulation reliability; polymer liner combinations; polymer material combinations; relative humidity; temperature 130 degC; thermal cycling tests; thermomechanical reliability; thermomechanical strains; thermomechanical stresses; thin glass interposers; thin glass packages; time 100 hour; voltage 5 V; Copper; Glass; Polymers; Reliability; Stress; Vehicles; Glass Interposer; Mechanical modeling; Reliability; TPV (Through Package Via); Temperature Cycling Test (TCT); biased-HAST (Highly Accelerated Stress testing);
Conference_Titel :
Electronic Components and Technology Conference (ECTC), 2013 IEEE 63rd
Conference_Location :
Las Vegas, NV
Print_ISBN :
978-1-4799-0233-0
DOI :
10.1109/ECTC.2013.6575595
