ALX Polymer for Wafer Level Packaging: Mechanical Property Evaluation After Multiple Lead-Free Solder Reflows

2010 ◽  
Vol 2010 (DPC) ◽  
pp. 001054-001079
Author(s):  
Takeshi Eriguchi ◽  
Orson Wang ◽  
Kaori Tsuruoka ◽  
Yuichiro Ishibashi ◽  
Yong Zhang
Keyword(s):  
Mechanical Property ◽  
Dielectric Constant ◽  
Moisture Absorption ◽  
Lead Free ◽  
Low Dielectric Constant ◽  
Lead Free Solder ◽  
Wafer Level ◽  
Low Dielectric ◽  
Wafer Level Packaging ◽  
Free Solder

For bumping and wafer level packaging (WLP) applications, BCB and polyimide are the predominant spin-on dielectric materials used for re-passivation, redistribution, interlayer dielectric, and stress buffer layers. Each of these materials has their respective strengths and weaknesses. BCB has exceptionally low shrinkage on cure and moisture absorption, low curing temperature, and a low dielectric constant, but is a mechanically brittle material which limits its application in bump-on-polymer applications. Polyimides are superior mechanically to BCB and are utilized more in bump-on-polymer structures, but suffer from much higher shrinkage on cure and moisture absorption (which can lead to blistering if not carefully processed), have higher dielectric constants, and have much higher cure temperatures. ALX spin-on polymer dielectric was developed to combine low shrinkage, low moisture absorption, low dielectric constant, and excellent mechanical and stress buffering properties with a cure temperature between 190C to 250C, depending on the application(1-3). Previous papers have reported the mechanical properties at 190C and the application of ALX in eutectic SnPb solder bump structures. The use of lead-free solder requires reflow temperatures up to 260C. Although ALX polymer is curable at less than 200C, the influence of lead-free solder reflow wasnft investigated. In this presentation we evaluate mechanical property changes of ALX Polymer films after different cure schedules and multiple reflows at lead-free solder temperatures. The impact of these parameters on WLP will be discussed.

Thermoplastic Optical Polymers with Lead-Free Solder Reflow Resistance for HB-LED Packaging and Assembly

2010 ◽  
Vol 2010 (1) ◽  
pp. 000156-000163
Author(s):  
Weijun Zhou ◽  
Quan Yuan ◽  
Chris Li ◽  
Stephen F. Hahn ◽  
Kurt A. Koppi ◽  
...  
Keyword(s):  
Block Copolymers ◽  
Dimensional Stability ◽  
Moisture Absorption ◽  
Lead Free ◽  
Lead Free Solder ◽  
Optical Polymers ◽  
Reflow Process ◽  
Short Period ◽  
Solder Reflow ◽  
Free Solder

A new class of thermoplastic optical polymers made by substantially fully hydrogenating block copolymers of styrene and butadiene, known as cyclic block copolymers (CBCs), were recently discovered to exhibit lead-free solder reflow resistance with peak reflow temperature up to 260°C. This kind of behavior is uncommon for traditional thermoplastic polymers. The block copolymer design and the resulting nanostructured morphology lead to strong elastic and soft solid material characteristics for CBC, which may explain why CBCs can maintain good dimensional stability at high temperatures (i.e., above its glass transition temperature, Tg) for a short period of time such as in a solder reflow process. This hypothesis was examined by computational fluid dynamics modeling on a molded CBC lens of LUXEON K2 LED package configuration. When the CBC lens is subjected to a simulated solder reflow process, the change in physical dimension due to thermal expansion and gravity effects is predicted to be negligible. However, the residual stress in the molded lens may play a profound role on its dimensional stability. There exists a critical stress value below which no observable deformation is predicted for the CBC lens. With excellent optical transparency and good long term optical stability, low moisture absorption, and good injection moldability, CBCs is a promising class of materials for LED packaging that contributes to improved LED manufacturing economics.

Microstructure Evolution, Thermal and Mechanical Property of Co Alloyed Sn-0.7Cu Lead-Free Solder

2020 ◽  
Vol 49 (4) ◽  
pp. 2660-2668 ◽  
Author(s):  
Jianglei Fan ◽  
Hengtao Zhai ◽  
Zhanyun Liu ◽  
Xiao Wang ◽  
Xiangkui Zhou ◽  
...  
Keyword(s):  
Mechanical Property ◽  
Microstructure Evolution ◽  
Lead Free ◽  
Lead Free Solder ◽  
Free Solder

Mechanical property analyses of porous low-dielectric-constant films for stability evaluation of multilevel-interconnect structures

2004 ◽  
Vol 460 (1-2) ◽  
pp. 167-174 ◽  
Author(s):  
Shou-Yi Chang ◽  
Hui-Lin Chang ◽  
Yung-Cheng Lu ◽  
Syun-Ming Jang ◽  
Su-Jien Lin ◽  
...  
Keyword(s):  
Mechanical Property ◽  
Dielectric Constant ◽  
Low Dielectric Constant ◽  
Stability Evaluation ◽  
Low Dielectric

The Effects of Temperature Cyclic Loading on Lead-Free Solder Joints of Wafer Level Chip Scale Package by Taguchi Method

2008 ◽  
Vol 130 (1) ◽  
Author(s):  
Wen-Ren Jong ◽  
Hsin-Chun Tsai ◽  
Hsiu-Tao Chang ◽  
Shu-Hui Peng
Keyword(s):  
Low Temperature ◽  
Shear Strain ◽  
Solder Joints ◽  
Strain Range ◽  
Lead Free ◽  
Lead Free Solder ◽  
Wafer Level ◽  
Chip Scale Package ◽  
Free Solder ◽  
Plastic Creep

In this study, the effects of the temperature cyclic loading on three lead-free solder joints of 96.5Sn–3.5Ag, 95.5Sn–3.8Ag-0.7Cu, and 95.5Sn–3.9Ag-0.6Cu bumped wafer level chip scale package (WLCSP) on printed circuit board assemblies are investigated by Taguchi method. The orthogonal arrays of L16 is applied to examine the shear strain effects of solder joints under five temperature loading parameters of the temperature ramp rate, the high and low temperature dwells, and the dwell time of both high and low temperatures by means of three simulated analyses of creep, plastic, and plastic-creep behavior on the WLCSP assemblies. It is found that the temperature dwell is the most significant factor on the effects of shear strain range from these analyses. The effect of high temperature dwell on the shear strain range is larger than that of low temperature dwell in creep analysis, while the effect of high temperature dwell on the shear strain range is smaller than that of low temperature dwell in both plastic and plastic-creep analyses.

Polynorbornene for Low K Interconnection

1997 ◽  
Vol 476 ◽  
Author(s):  
N. R. Grove ◽  
P. A. Kohl ◽  
S. A. Bidstrup-Allen ◽  
R. A. Shick ◽  
B. L. Goodall ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Moisture Absorption ◽  
Electrical Performance ◽  
Low Dielectric Constant ◽  
High Glass Transition Temperature ◽  
Low Dielectric ◽  
Microelectronics Industry

AbstractWithin the microelectronics industry, there is an ongoing trend toward miniaturization coupled with higher performance. The scaling of transitors toward smaller dimensions, higher speeds, and lower power has resulted in an urgent need for low dielectric constant interlevel insulators. Low dielectric constant interlevel dielectrics have already been identified as being critical to the realization of high performance integrated circuits in the SLA Roadmap. Thus, there exists a need in the microelectronics industry for a thermally stable, noncorrosive low dielectric constant polymer with good solvent resistance, high glass transition temperature, good mechanical performance and good adhesive properties, particularly to copper. In addition, the desired dielectric material should be capable of being processed in environmentally friendly solvents, and the final thermal and electrical performance should not be affected by manufacturing or post environmental conditions. High glass transition temperature polynorbornenes are being developed which provide many of these desired features. This polymer family is produced via a new transition metal catalyzed polymerization. Attributes which make polynorbornene particularly attractive in microelectronics include: (i) excellent thermal performance, (ii) adhesion to conductors without the use of adhesion promoters or barrier layers, (iii) very low moisture absorption (< 0.1 wt %), and (iv) low dielectric constant (2.2 – 2.6). Side groups which have been added to the polynorbornene backbone improve adhesion, dielectric properties and mechanical properties.

Poly(Arylene Ethers) as Low Dielectric Constant Materials for ULSI Interconnect Applications

1996 ◽  
Vol 443 ◽  
Author(s):  
Raymond N. Vrtis ◽  
Kelly A. Heap ◽  
William F. Burgoyne ◽  
Lloyd M. Robeson
Keyword(s):  
Thermal Stability ◽  
Dielectric Constant ◽  
Moisture Absorption ◽  
Dielectric Material ◽  
Mechanical Analysis ◽  
Low Dielectric Constant ◽  
Low Dielectric ◽  
Arylene Ether ◽  
Low Dielectric Constant Materials ◽  
Excellent Adhesion

AbstractPoly(arylene ethers)s are low dielectric constant organic spin on materials. PAE-2, which is a non-fluorinated poly(arylene ether), exhibits a dielectric constant below 3.0, thermal stability greater than 425 °C as well as excellent adhesion to Si, SiO2, and Al. These are the major atributes which makes it a very attractive candidate for integration as an interlevel or inter-metal dielectric material (ILD). Material properties including dielectric constant, thermal stability, moisture absorption, and mechanical analysis will be discussed.

Creep Analysis of Wafer Level Chip Scale Package (WLCSP) With 96.5Sn-3.5Ag and 100In Lead-Free Solder Joints and Microvia Build-Up Printed Circuit Board

2000 ◽  
Author(s):  
John H. Lau ◽  
Stephen H. Pan ◽  
Chris Chang
Keyword(s):  
Shear Stress ◽  
Printed Circuit Board ◽  
Circuit Board ◽  
Lead Free ◽  
Lead Free Solder ◽  
Wafer Level ◽  
Shear Creep ◽  
Printed Circuit ◽  
Chip Scale Package ◽  
Free Solder

Abstract In this study, time-temperature-dependent nonlinear analyses of lead-free solder bumped wafer level chip scale package (WLCSP) on printed circuit board (PCB) assemblies subjected to thermal cycling conditions are presented. Two different lead-free solder alloys are considered, namely, 96.5wt%Sn-3.5wt%Ag and 100wt%In. The 62wt%Sn-36wt%Pb-2wt%Ag solder alloy is also considered to establish a baseline. All of these solder alloys are assumed to obey the Garofalo-Arrhenius steady-state creep constitutive law. The shear stress and shear creep strain hysteresis loops, shear stress history, and shear creep strain history at the corner solder joint are presented for a better understanding of the thermal-mechanical behaviors of lead-free solder bumped WLCSP on PCB assemblies. Also, the effects of microvia build-up PCB on the WLCSP solder joint reliability are investigated.

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