Multiphysics Model for Chlorine-Ion Related Corrosion in Cu-Al Wirebond Microelectronic Packages

2015 ◽  
Author(s):  
Pradeep Lall ◽  
Yihua Luo ◽  
Luu Nguyen
Keyword(s):  
Inductively Coupled Plasma ◽  
Galvanic Corrosion ◽  
Copper Wire ◽  
Open Circuit ◽  
Chloride Ions ◽  
Thermal Resistivity ◽  
Molding Compound ◽  
Wire Bond ◽  
Electrolytic Corrosion ◽  
Microelectronic Packages

The increasing price of gold has resulted in industry interest in use of copper as alternative wire bonds interconnect material. Copper wire has the advantages of the lower cost, lower thermal resistivity, lower electrical resistivity, higher mechanical strength and higher deformation stability over the gold wire. In spite of the upside above, the Cu-Al wire bond is susceptible to the electrolytic corrosion and the reliability of Cu-Al wire bond is of great concern. Typical electronic molding compounds are hydrophilic and absorb moisture when exposed to humid environmental conditions. EMC contain ionic contaminants including chloride ions as a result of the chemical synthesis of the subcomponents of the resin, etching of metallization and the decomposition of the die-attach glue. The presence of moisture in the operating environment of semiconductor package makes the ion more mobile in the EMC. The migration of chloride ions to the Cu-Al interface may induce electrolytic corrosion inside the package causing degradation of the bond interface resulting in eventual failure. The rate at which the corrosion happens in the microelectronic packages is dependent upon the rate at which the ions transport through the EMC in addition to the reaction rate at the interface. In this effort, a multiphysics model for galvanic corrosion in the presence of chloride has been presented. The contaminant diffusion along with the corrosion kinetics has been modeled. In addition, contaminated samples with known concentration of KCl contaminant have been subjected to the temperature humidity conditions of 130°C/100RH. The resistance of the Cu-Al interconnects in the PARR test have been monitored periodically using resistance spectroscopy. The diffusion coefficients of chloride ion has been measured in the electronic molding compound at various temperatures using two methods including diffusion cell and inductively coupled plasma (ICPMS). Moisture ingress into the EMC has been quantified through measurements of the weight gain in the EMC as a function of time. Tafel parameters including the open circuit potential and the slope of the polarization curve has been measured for both copper, aluminum under different concentrations of the ionic species and pH values in the EMC. The measurements have been incorporated into the COMSOL model to predict the corrosion current at the Cu-Al bond pad. The model predictions have been correlated with experimental data.

Chlorine-Ion Related Corrosion in Cu-Al Wirebond Microelectronic Packages

2015 ◽  
Author(s):  
Pradeep Lall ◽  
Yihua Luo ◽  
Luu Nguyen
Keyword(s):  
Diffusion Coefficients ◽  
Inductively Coupled Plasma ◽  
Copper Wire ◽  
Chloride Ions ◽  
Thermal Resistivity ◽  
Comsol Multiphysics ◽  
Molding Compound ◽  
Wire Bond ◽  
Electrolytic Corrosion ◽  
Microelectronic Packages

The increasing price of gold has resulted in industry interest in use of copper as alternative wire bonds interconnect material. Copper wire has the advantages of the lower cost, lower thermal resistivity, lower electrical resistivity, higher mechanical strength and higher deformation stability over the gold wire. In spite of the upside above, the Cu-Al wire bond is susceptible to the electrolytic corrosion and the reliability of Cu-Al wire bond is of great concern. Typical electronic molding compounds are hydrophilic and absorb moisture when exposed to humid environmental conditions. EMC contain ionic contaminants including chloride ions as a result of the chemical synthesis of the subcomponents of the resin, etching of metallization and the decomposition of the die-attach glue. The presence of moisture in the operating environment of semiconductor package makes the ion more mobile in the EMC. The migration of chloride ions to the Cu-Al interface may induce electrolytic corrosion inside the package causing degradation of the bond interface resulting in eventual failure. The rate at which the corrosion happens in the microelectronic packages is dependent upon the rate at which the ions transport through the EMC in addition to the reaction rate at the interface. In this effort, a multiphysics model for electrolytic corrosion in the presence of chloride has been presented. The contaminant diffusion along with the corrosion kinetics has been modeled. In addition, contaminated samples with known concentration of KCl contaminant have been subjected to the temperature humidity conditions (130°C/100RH)The resistance of the Cu-Al interconnects in the PARR test have been monitored periodically using resistance spectroscopy. The diffusion coefficients of chloride ion at various temperatures in the molding compound have been measured using inductively coupled plasma. Measured diffusion coefficients have been incorporated into the COMSOL multiphysics model. Moisture ingress into the EMC has been quantified through measurements of the weight gain in the EMC. Predictions from the COMSOL multiphysics model have been correlated with experimental data.

Reliability Assessment of Cu-Al WB Under High Temperature and High Voltage Bias Application

2020 ◽  
Author(s):  
Pradeep Lall ◽  
Sungmo Jung
Keyword(s):  
High Temperature ◽  
High Voltage ◽  
Galvanic Corrosion ◽  
Copper Wire ◽  
Ionic Transport ◽  
Gold Wire ◽  
Process Window ◽  
Voltage Bias ◽  
Wire Bond ◽  
Wire Bonds

Abstract Electronics in automotive underhood environments may be subjected to high temperature in the range of 125–200°C. Transition to electric vehicles has resulted in need for electronics capable of operation under high voltage bias. Automotive electronics has simultaneously transitioned to copper wire-bond from gold wire-bond for first-level interconnections. Copper has a smaller process window and a higher propensity for corrosion in comparison with gold wire bonds. There is scarce information on the reliability of copper wire bonds in presence of high voltage bias under operation at high temperature. In this paper, a multiphysics model for micro galvanic corrosion in the presence of chlorine is introduced. The diffusion cell is used to measure the diffusivity of chlorine in different pH values and different temperatures. Diffusivity measurements are incorporated into the 3D ionic transport model to study the effect of different environmental factors on the transport rate of chlorine. The tafel parameters for copper, aluminum and intermetallics have been extracted through measurements of the polarization curves. The multiple physics of ionic transport in presence of concentration gradient, potential gradient is coupled with the galvanic corrosion.

High Temperature Storage and HAST Reliability of Copper-Aluminum Wirebond Interconnects

2014 ◽  
Author(s):  
Pradeep Lall ◽  
Shantanu Deshpande ◽  
Luu Nguyen
Keyword(s):  
High Temperature ◽  
Copper Wire ◽  
Gold Wire ◽  
Wire Bonding ◽  
Remaining Useful Life ◽  
Thermal Resistivity ◽  
Wire Bond ◽  
Trade Offs ◽  
Marquardt Algorithm ◽  
Temperature And Humidity

Gold wire bonding has been widely used as first-level interconnect in semiconductor packaging. The increase in the gold price has motivated the industry search for alternative to the gold wire used in wire bonding and the transition to copper wire bonding technology. Potential advantages of transition to Cu-Al wire bond system includes low cost of copper wire, lower thermal resistivity, lower electrical resistivity, higher deformation strength, damage during ultrasonic squeeze, and stability compared to gold wire. However, the transition to the copper wire brings along some trade-offs including poor corrosion resistance, narrow process window, higher hardness, and potential for cratering. Formation of excessive Cu-Al intermetallics may increase electrical resistance and reduce the mechanical bonding strength. Current state-of-art for studying the Cu-Al system focuses on accumulation of statistically significant number of failures under accelerated testing. In this paper, a new approach has been developed to identify the occurrence of impending apparently-random defect fall-outs and pre-mature failures observed in the Cu-Al wirebond system. The use of intermetallic thickness, composition and corrosion as a leading indicator of failure for assessment of remaining useful life for Cu-al wirebond interconnects has been studied under exposure to high temperature and temperature-humidity. Damage in wire bonds has been studied using x-ray Micro-CT. Microstructure evolution was studied under isothermal aging conditions of 150°C, 175°C, and 200°C till failure. Activation energy was calculated using growth rate of intermetallic at different temperatures. Effect of temperature and humidity on Cu-Al wirebond system was studied using Parr Bomb technique at different elevated temperature and humidity conditions (110°C/ 100%RH, 120°C/ 100%RH, 130°C/ 100%RH) and failure mechanism was developed. The present methodology uses evolution of the IMC thickness, composition in conjunction with the Levenberg-Marquardt algorithm to identify accrued damage in wire bond subjected to thermal aging. The proposed method can be used for quick assessment of Cu-Al parts to ensure manufactured part consistency through sampling.

Heat Treatment Influence on the Corrosion Resistance of a Cu-Al-Fe-Mn Bronze

2018 ◽  
Vol 69 (5) ◽  
pp. 1055-1059 ◽  
Author(s):  
Mariana Ciurdas ◽  
Ioana Arina Gherghescu ◽  
Sorin Ciuca ◽  
Alina Daniela Necsulescu ◽  
Cosmin Cotrut ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Structural Changes ◽  
Heating Temperature ◽  
Galvanic Corrosion ◽  
Cooling Water ◽  
Open Circuit ◽  
Water Quenching ◽  
Heat Treated ◽  
Different Temperatures

Aluminium bronzes are exhibiting good corrosion resistance in saline environments combined with high mechanical properties. Their corrosion resistance is obviously confered by the alloy chemical composition, but it can also be improved by heat treatment structural changes. In the present paper, five Cu-Al-Fe-Mn bronze samples were subjected to annealing heat treatments with furnace cooling, water quenching and water quenching followed by tempering at three different temperatures: 200, 400 and 550�C. The heating temperature on annealing and quenching was 900�C. The structure of the heat treated samples was studied by optical and scanning electron microscopy. Subsequently, the five samples were submitted to corrosion tests. The best resistance to galvanic corrosion was showed by the quenched sample, but it can be said that all samples are characterized by close values of open-circuit potentials and corrosion potentials. Concerning the susceptibility to other types of corrosion (selective leaching, pitting, crevice corrosion), the best corrosion resistant structure consists of a solid solution, g2 and k compounds, corresponding to the quenched and 550�C tempered sample.

Corrosion surveillance program for tank, fuel cladding and supporting structure of 30 MW Indonesian RSG GAS research reactor

Kerntechnik ◽  
2021 ◽  
Vol 86 (3) ◽  
pp. 236-243
Author(s):  
G. R. Sunaryo ◽  
R. Kusumastuti ◽  
Sriyono
Keyword(s):  
Water Quality ◽  
Power Plants ◽  
Research Reactor ◽  
Visual Analysis ◽  
Galvanic Corrosion ◽  
Steel Wire ◽  
Chloride Ions ◽  
Bottom Surface ◽  
Surveillance Program ◽  
Probe Set

Abstract The objective of this research is to understand the condition of the structural material of the 30 MW RSG-GAS research reactor as input for the aging management program. Furthermore, this should enable a prediction of the remaining life of the components. In the current experiment, corrosion surveillance was carried out at Interim Storage for Spent Fuel (ISSF), that has similar water quality as in reactor pool by using a corrosion probe which is made of aluminum alloy and stainless steel. The probe set is designed to understand the effect of water quality in the ISSF pond. The corrosion processes observed were pitting, crevice and galvanic corrosion. Two sets of corrosion probes were immersed into the ISSF pool in 2007, hanging by steel wire, 1-meter height from the bottom surface. One probe set consists of horizontal and vertical positions. The soaking time was 7 years. The observations made were water chemical content, corrosion rate and visual analysis, macro and micro. For macro visual observations an optical microscope was used, for micro-observations SEM-EDX. From the results of macro-observations, information on the presence of galvanic corrosion, crevice and pitting was obtained. SEM-EDX provides information on the influence of chloride ions on corrosion products. This experience will be very useful in dealing with the aging process of Indonesia’s nuclear power plants in the future.

Copper Wire Bond Optimization for Power Devices

2018 ◽  
Author(s):  
T. Pinili ◽  
R. Watkins ◽  
W. Qin ◽  
G. Brizar ◽  
J. De Clerq ◽  
...  
Keyword(s):  
Copper Wire ◽  
Power Devices ◽  
Wire Bond

Study of Factors Contributing to Robust Copper Wire Bond on QFN

2019 ◽  
Vol 44 (1) ◽  
pp. 985-989
Author(s):  
Tan Boo Wei ◽  
Ken Niu
Keyword(s):  
Copper Wire ◽  
Wire Bond

scholarly journals The influence of gelatine on the corrosion behaviour of cold worked copper wire in alkaline media

2006 ◽  
Vol 42 (1) ◽  
pp. 33-43 ◽  
Author(s):  
Svetlana Ivanov ◽  
Mirjana Rajcic-Vujasinovic ◽  
Zoran Stevic
Keyword(s):  
Corrosion Rate ◽  
Corrosion Behaviour ◽  
Copper Wire ◽  
Positive Influence ◽  
Open Circuit ◽  
Alkaline Media ◽  
Forming Process ◽  
Deformation Degree ◽  
Cold Worked ◽  
Potentiodynamic Method

Copper wire obtained by dip-forming process was cold worked to the deformation degrees of 83, 87, 91, 95 and 99 %. Electrochemical potentiodynamic method was used to investigate corrosion behavior of these wires in aqueous solutions of Na2CO3 (1 mol/dm3). Open circuit potentials as well as peak potentials are given as a function of deformation degree in Na2CO3 without and with addition of gelatine in concentration between 0.1 and 0.5 g/l. It was found that the addition of gelatine does not change the mechanism of the process, but influences on current density. Small concentrations of gelatine (0.1 g/l or less) have positive influence on the corrosion protection of copper in alkaline solution, but the addition of gelatine in concentration 0.5 g/l causes the increasing of its corrosion rate.

Modeling Vibration Induced Fatigue Failure of Free Standing Wire Bonds

2017 ◽  
Vol 2017 (1) ◽  
pp. 000635-000640
Author(s):  
Zhenzhen Shen ◽  
James Storey ◽  
Otto Fanini ◽  
Michael Osterman
Keyword(s):  
Natural Frequency ◽  
Electronic Device ◽  
Experimental Testing ◽  
Preliminary Test ◽  
Time To Failure ◽  
Free Standing ◽  
Element Analysis ◽  
Molding Compound ◽  
Wire Bond ◽  
Wire Bonds

Abstract Wire bonds are used to connect device terminals to package terminals or substrate terminal that forms circuits that are needed to create desired higher level functions. If a wire bond breaks or becomes detached during operation, the desired function will be lost. Depending on the design, a loss in function could be catastrophic. Aluminum, gold, and copper wires are used to create wire bonds in electronic products. These materials have been selected for their ability to be formed as fine wires and their ability to provide low electrical resistance. In many electronics packages, wire bonds are encapsulated in a polymer molding compound that is used to protect the electronic device. However, in some electronic devices such as hermetically sealed cavity packages, wire bonds may be free-standing. Under vibration loading, free-standing wire bonds may be subject to failure due to mechanical fatigue. In this work, an analytic model is presented for predicting natural frequency of a free-standing wire bond and for assessing a wire bond time to failure under a harmonic loading condition. The model for natural frequency is calibrated by finite element analysis and validated through experimental testing. The life prediction model, a test plan, and preliminary test results are presented.

Sign in / Sign up

Export Citation Format

Share Document