Next-Generation Lead-Free Solder Plating Products for High Speed Bumping, Capping and Micro-Capping Applications

2013 ◽  
Vol 2013 (1) ◽  
pp. 000458-000460
Author(s):  
Jonathan Prange ◽  
Julia Woertink ◽  
Yi Qin ◽  
Pedro Lopez Montesinos ◽  
Inho Lee ◽  
...  
Keyword(s):  
High Speed ◽  
Flip Chip ◽  
Lower Cost ◽  
Lead Free ◽  
Height Distribution ◽  
Lead Free Solder ◽  
Next Generation ◽  
Organic Additives ◽  
Microelectronic Devices ◽  
Free Solder

Flip-chip interconnect and 3-D packaging applications must utilize reliable lead-free solder joints in order to produce highly efficient, advanced microelectronic devices. The solder alloy most commonly utilized for these applications is SnAg, which is typically deposited by electroplating due to lower cost and greater reliability as compared to other methods. The electroplating performance and robustness of SnAg products for bumping and capping applications is highly dependent on the organic additives used in the process. Here, next-generation SnAg products that improve the rate of solder electrodeposition without compromising key requirements such as tight Ag% control, uniform height distribution and smooth surface morphology will be discussed. These plated solders were then evaluated for compatibility with bumping, capping and micro-capping applications.

Next-Generation Copper, Nickel and Lead-Free Metallization Products for Next-Generation Devices and Applications

2015 ◽  
Vol 2015 (DPC) ◽  
pp. 000611-000638
Author(s):  
Jonathan Prange ◽  
Yi Qin ◽  
Matthew Thorseth ◽  
Inho Lee ◽  
Masaaki Imanari ◽  
...  
Keyword(s):  
High Performance ◽  
Flip Chip ◽  
Low Cost ◽  
Lead Free ◽  
Lead Free Solder ◽  
Next Generation ◽  
Copper Nickel ◽  
Microelectronic Devices ◽  
Architectural Features ◽  
Free Solder

Flip-chip interconnect and 3-D packaging applications must utilize reliable, high-performance metallization products in order to produce highly-efficient, low-cost microelectronic devices. As the market moves to shrinking device architectural features and increasingly difficult pattern layouts, more demand is placed on the plating performance of the copper, nickel and lead-free solder products used to create these interconnects. Additionally, the move from traditional C4 bumping processes with lead-free solder to capping processes utilizing copper pillars with lead-free solder requires metal interfaces that are highly compatible in order to avoid defects that could occur. In this paper, next-generation products developed for copper pillar, nickel barrier, and lead-free solder plating will be introduced that are capable of delivering high-performance and highly reliable metallic interconnects. The additive packages that were selected and optimized allowing for increased rate of electrodeposition, uniform height control with controllable pillar shape and smooth surface morphology will be discussed. Furthermore, compatibility will be shown for a lead-free solder cap electrodeposited onto copper pillar structures, both with and without nickel barrier layers, on large pore features (≥50 μm diameter) and micro pore features (≤20 μm diameter) for both bumping and capping applications.

scholarly journals Growth Kinetics of Reaction Layers in Flip Chip Joints with Cu-cored Lead-free Solder Balls

2004 ◽  
Vol 45 (3) ◽  
pp. 754-758 ◽  
Author(s):  
Ikuo Shohji ◽  
Yuji Shiratori ◽  
Hiroshi Yoshida ◽  
Masahiko Mizukami ◽  
Akira Ichida
Keyword(s):  
Growth Kinetics ◽  
Flip Chip ◽  
Lead Free ◽  
Lead Free Solder ◽  
Solder Balls ◽  
Free Solder ◽  
Kinetics Of Reaction ◽  
Kinetics Of

Control of Bump Morphology in Lead Free Solder Plating for Higher Density Packaging

2014 ◽  
Vol 2014 (DPC) ◽  
pp. 001643-001669
Author(s):  
Koji Tatsumi ◽  
Kyouhei Mineo ◽  
Takeshi Hatta ◽  
Takuma Katase ◽  
Masayuki Ishikawa ◽  
...  
Keyword(s):  
High Speed ◽  
Flip Chip ◽  
New Technologies ◽  
Short Circuit ◽  
Lead Free Solder ◽  
Cu Pillar ◽  
Fine Pitch ◽  
Different Shapes ◽  
Free Solder ◽  
High Density Packaging

Solder bumping is one of the key technologies for flip chip connection. Flip chip connection has been moving forward to its further downsizing and higher integration with new technologies, such as Cu pillar, micro bump and Through Silicon Via (TSV). Unlike some methods like solder printing and ball mounting, electroplating is a very promising technology for upcoming finer bump formation. We have been developing SnAg plating chemical while taking technology progress and customers' needs into consideration at the same time. Today, we see more variety of requests including for high speed plating to increase the productivity and also for high density packaging such as narrowing the bump pitch itself and downsizing of the bump diameter. To meet these technical needs, some adjustments of plating chemical will be necessary. This time we developed new plating chemicals to correspond to bump miniaturization. For instance, our new SnAg chemical can control bump morphology while maintaining the high deposition speed. With our new plating chemicals, we can deposit mushroom bumps that grow vertically against the resist surface, also this new chemicals work effectively to prevent short-circuit between mushroom bumps with fine pitch from forming. In addition, we succeeded in developing high speed Cu pillar plating chemicals that can control the surface morphology to create different shapes. We'd like to present our updates on controlling bump morphology for various applications.

Practical Application and Analysis of Lead-Free Solder on Chip-On-Flip-Chip SiP for Hearing Aids

2017 ◽  
Vol 2017 (1) ◽  
pp. 000201-000207 ◽  
Author(s):  
Youngtak Lee ◽  
Doug Link
Keyword(s):  
Hearing Aids ◽  
Flip Chip ◽  
Failure Modes ◽  
Lead Free ◽  
Lead Free Solder ◽  
Solder Paste ◽  
Practical Application ◽  
Surface Mount ◽  
Free Solder ◽  
On Chip

Abstract Due to rapid growth of the microelectronics industry, packaged devices with small form factors, low costs, high power performance, and increased efficiency have become of high demand in the market. To realize the current market development trend, flip chip interconnection and System-in-Package (SiP) are some of the promising packaging solutions developed. However, a surprising amount of surface mount technology (SMT) defects are associated with the use of lead-free solder paste and methods by which the paste is applied. Two such defects are solder extrusion and tombstoning. Considerable amount of defects associated with solder overflow are found on chip-on-flip-chip (COFC) SiP in hearing aids. Through the use of design of experiments (DOE), lead-free solder defect causes on hearing aids application can be better understood and subsequently reduced or eliminated. This paper will examine the failure modes of solder extrusion and tombstoning that occurred when two different types of lead-free solders, Sn-Ag-Cu (SAC) and BiAgX were used within a SiP for attachment of surface mount devices (SMD) chip components for hearing aid applications. The practical application and analysis of lead-free solder for hearing aids will include the comprehensive failure analysis of the SMD components and compare the modeling and analysis of the two different solder types through the DOE process.

Study on electromigration in flip chip lead-free solder connections with 40 μm or 30 μm diameter on thin film ceramic substrates

2015 ◽  
Vol 2015 (1) ◽  
pp. 000799-000805
Author(s):  
Marek Gorywoda ◽  
Rainer Dohle ◽  
Bernd Kandler ◽  
Bernd Burger
Keyword(s):  
Thin Film ◽  
High Stability ◽  
Flip Chip ◽  
Lead Free ◽  
Published Data ◽  
Organic Substrates ◽  
Lead Free Solder ◽  
Ceramic Substrates ◽  
Solder Bumps ◽  
Free Solder

Electromigration comprises one of the processes affecting the long-term reliability of electronic devices; it has therefore been the focus of many investigations in recent years. In regards to flip chip packaging technology, the majority of published data is concerned with electromigration in solder connections to metallized organic substrates. Hardly any information is available in the literature on electromigration in lead-free solder connections on thin film ceramic substrates. This work presents results of a study of electromigration in lead-free (SAC305) flip chip solder bumps with a nominal diameter of 40 μm or 30 μm with a pitch of 100 μm on silicon chips assembled onto thin film Al2O3 ceramic substrates. The under bump metallization (UBM) comprised of a 5 μm thick electroless nickel immersion gold (ENIG) layer directly deposited on the AlCu0.5 trace. The ceramic substrates were metallized using a thin film multilayer (NiCr-Au(1.5 μm)-Ni(2 μm) structure on the top of which wettable areas were produced with high precision by depositing flash Au (60 nm) of the required diameter (40 μm or 30 μm). All electromigration tests were performed at the temperature of 125 °C. Initially, one chip assembly with 40 μm and one with 30 μm solder bumps was loaded with the current density of 8 kA/cm2 for 1,000 h. The assemblies did not fail and an investigation with SEM revealed no significant changes to the microstructure of the bumps. Thereafter seven chip assemblies with 40 μm solder bumps and five assemblies with 30 μm bumps were subjected to electromigration tests of 14 kA/cm2 or 25 kA/cm2, respectively. Six of the 40 μm-assemblies failed after 7,000 h and none of the 30 μm-assemblies failed after 2,500 h of test duration so far. Investigation of failed samples performed with SEM and EDX showed asymmetric changes of microstructure in respect to current flow. Several intermetallic phases were found to form in the solder. The predominant damage of the interconnects was found to occur at the cathode contact to chip; the Ni-P layers there showed typical columnar Kirkendall voids caused by migration of Ni from the layers into the solder. Failure of the contacts apparently occurred at the interface between Ni-P and solder. In summary, the results of the study indicate a very high stability of lead-free solder connections on ceramic substrates against electromigration. This high stability is primarily due to a better heat dissipation and thus to a relatively low temperature increase of the ceramic packages caused by resistive heating during flow of electric current. In addition, the type of the metallization used in the study seems to be more resistant to electromigration than the standard PCB metallization as it does not contain a copper layer.

Comparative Modeling and Analysis of Lead-Free Solder Extrusion for the Design of Reliability

2016 ◽  
Vol 2016 (1) ◽  
pp. 000111-000116
Author(s):  
Youngtak Lee ◽  
Doug Link
Keyword(s):  
Design Of Experiments ◽  
Flip Chip ◽  
Failure Modes ◽  
Form Factors ◽  
Lead Free ◽  
Lead Free Solder ◽  
Solder Paste ◽  
Modeling And Analysis ◽  
Surface Mount ◽  
Free Solder

Abstract Due to rapid growth of the microelectronics industry, packaged devices with small form factors, low costs, high power performance, and increased efficiency have become of high demand in the market. To realize the current market development trend, flip chip interconnection and System-in-Package (SiP) are some of the promising packaging solutions developed. However, a surprising amount of surface mount technology (SMT) defects are associated with the use of lead-free solder paste and methods by which the paste is applied. Two such defects are solder extrusion and tombstoning. Through the use of design of experiments (DOE), lead-free solder defect causes can be better understood and subsequently reduced or eliminated. This paper will examine the failure modes of solder extrusion and tombstoning that occurred when two different types of lead-free solders, Sn-Ag-Cu (SAC) and BiAgX were used within a SiP for attachment of surface mount devices (SMD) chip components. The systematic investigation will include the comprehensive failure analysis of the SMD components and compare the modeling and analysis of the two different solder types utilizing the design of experiments methods.

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