Solderability and Reliability of Sintered Nano-Ag Bond Pads of Printed Re-Distribution Layer (RDL)

2021 ◽  
Author(s):  
S. W. R. Lee ◽  
J. C. C. Lo ◽  
X. Qiu ◽  
N. Tu
Keyword(s):  
High Temperature ◽  
Solder Joint ◽  
Wafer Level ◽  
Joint Reliability ◽  
Ball Shear Test ◽  
Alternative Approach ◽  
High Temperature Storage ◽  
Bond Pads ◽  
Photolithography Process ◽  
Temperature Storage

Abstract Re-distribution layer (RDL) is one key enabling technology for advance packaging. RDL is usually fabricated in wafer level by photolithography process. An alternative approach for implementing RDL by additive manufacturing (AM) method is proposed in this study. This allows RDL to be fabricated on singulation chip. Nano-silver (nano-Ag) ink is printed on the silicon chip to form routing traces and bond pads. However, the Ag pad may be consumed by solder quickly if the process is not properly controlled. This paper studied the effect of nano-Ag ink sintering condition on the solderability of Ag pad. The solder joint mechanical integrity was evaluated by solder ball shear test. High temperature storage test was also carried out to evaluate the solder joint reliability. Experiment results showed that Ag pad fabricated by AM is SMT compatible. High temperature storage did not cause early failure to the samples. There was not significant change in the Ag3Sn IMC layer thickness and mechanical strength. The finding of the present study will serve as a very useful reference for future practice of forming solder joints on sintered nano-Ag pads.

Effect of Fe content on the interfacial reliability of SnAgCu/Fe-Ni solder joint

2013 ◽  
Vol 2013 (1) ◽  
pp. 000109-000114
Author(s):  
Hao Zhang ◽  
Qing-Sheng Zhu ◽  
Zhi-Quan Liu ◽  
Li Zhang ◽  
Hongyan Guo ◽  
...  
Keyword(s):  
High Temperature ◽  
Solder Joint ◽  
Solder Joints ◽  
Temperature Cycling ◽  
Growth Speed ◽  
Fe Content ◽  
Ball Shear Test ◽  
High Temperature Storage ◽  
Interfacial Reliability ◽  
Temperature Storage

Fe-Ni films with compositions of Fe-75Ni, Fe-50Ni, and Fe-30Ni were used as under bump metallization (UBM) to evaluate the interfacial reliability of SnAgCu/Fe-Ni solder joints through ball shear test, high temperature storage, as well as temperature cycling. The shear strength for Fe-75Ni, Fe-50Ni, and Fe-30Ni solder joints after reflow were 42.57, 53.94, 53.98 MPa respectively, which are all satisfied with the requirement of industrialization (>34.3 MPa ). High temperature storage was conducted at 150°C and 200°C respectively. It was found that higher Fe content in Fe-Ni layer had the ability to inhibit the mutual diffusion at interface region at 150°C, and the growth speed of intermetallic compound (IMC) decreased with the increase of Fe concentration. When stored at 200°C, the thickness of IMC would reach a limitation for all these three films after 4 days, and cracks occurred at the interface between IMC and Fe-Ni layer. Temperature cycling tests revealed that SnAgCu/Fe-50Ni solder joint had the lowest failure rate (less than 10%), which has the best interfacial reliability among three compositions.

Active and Passive Devices Embedded in Laminate-Based Multilayer Board

2012 ◽  
Vol 2012 (DPC) ◽  
pp. 001253-001283
Author(s):  
Satoshi Okude ◽  
Kazushisa Itoi ◽  
Masahiro Okamoto ◽  
Nobuki Ueta ◽  
Osamu Nakao
Keyword(s):  
High Temperature ◽  
Thermal Cycling ◽  
Flip Chip ◽  
Wafer Level ◽  
Active Device ◽  
Electrical Connection ◽  
Passive Devices ◽  
High Temperature Storage ◽  
Circuit Resistance ◽  
Temperature Storage

We have developed active and passive devices embedded multilayer board utilizing our laminate-based WLCSP embedding technology. The proposed embedded board is realized by laminating plural circuit formed polyimide films together by adhesive with thin devices being arranged in between those polyimide layers. The electrical connection via has a filled via structure composed of the alloy forming conductive paste which ensures high reliable connection. The embedded active device is WLCSP which has no solder bump on its pads therefore the thickness of the die is reduced to 80 microns. The embedded passive device is a chip resistor or capacitor whose thickness is 150 microns with copper electrodes. The electrical connection between components and board's circuits are made by same conductive paste vias. The thin film based structure and low profile devices yields the 260 microns thickness board which is the thinnest embedded of its kind in the world. To confirm the reliability of the embedded board, we have performed several reliability tests on the WLCSP and resistors embedded TEG board of 4 polyimide/5 copper circuit layers. As environmental tests, we performed a moisture reflow test compliant to JEDEC MSL2 followed by a thermal cycling test (−55 deg.C to 125 deg.C, 1000cycles) and a high temperature storage test (150 deg.C). All tested samples passed the moisture reflow test and showed no significant change of circuit resistance after the thermal cycling/high temperature storage tests. Moreover, mechanical durability of the board was also confirmed by bending the devices embedded portion. The embedded device was never broken and the circuit resistance change was also within acceptable range. The proposed embedded board will open up a new field of device packaging. Alan/Rey ok move from Flip Chip and Wafer Level Packaging 1-3-12.

High Temperature Storage Reliability of Bond Resistance of Palladium-Coated Copper Ball Bonds

2017 ◽  
Vol 2017 (1) ◽  
pp. 000432-000437 ◽  
Author(s):  
Michael David Hook ◽  
Michael Mayer ◽  
Stevan Hunter
Keyword(s):  
High Temperature ◽  
Ball Bond ◽  
Wire Bonds ◽  
High Temperature Storage ◽  
Ball Bonding ◽  
Ball Bonds ◽  
Bond Pads ◽  
Wire Resistance ◽  
Temperature Storage

Abstract Reliability of wire bonds made with palladium-coated copper (PCC) wire of 25 μm diameter is studied by measuring the wire bond resistance increase over time in high temperature storage at 225 °C. Ball bonds are made on two bond pad thicknesses and tested with and without mold compound encapsulation. Bond pads are aluminum copper (Al-0.5%Cu), 800 nm and 3000 nm thick. The wirebonding pattern is arranged to facilitate 4-wire resistance measurements of 12 bond pairs in each 28-pin ceramic test package. The ball bonding recipe is optimized to minimize splash on 3000 nm Al-0.5%Cu with shear strength at least 120 MPa. Ball bond diameter is 61 μm and height is 14 μm. Measurements include bond shear test data and in-situ resistance before and during high temperature storage. Bonds on 3000 nm pads are found to be significantly more reliable than bonds on 800 nm pads within 140 h of aging.

scholarly journals Effect of Isothermal Aging and Copper Substrate Roughness on the SAC305 Solder Joint Intermetallic Layer Growth of High Temperature Storage (HTS)

2020 ◽  
Vol 49 (12) ◽  
pp. 2999-3008
Author(s):  
Rabiah Al Adawiyah Ab Rahim ◽  
Muhammad Nubli Zulkifli ◽  
Azman Jalar ◽  
Atiqah Mohd Afdzaluddin ◽  
Siow Shyong Kim
Keyword(s):  
High Temperature ◽  
Solder Joint ◽  
Aging Process ◽  
Turning Point ◽  
Copper Substrate ◽  
Sac305 Solder ◽  
Initial Exposure ◽  
Cu Substrate ◽  
High Temperature Storage ◽  
Temperature Storage

This study aims to evaluate the effect of copper (Cu) substrate surface roughness on the intermetallic compound (IMC) growth and interfacial reaction of SAC305 lead-free solder joint after undergone an aging process. Aging process was conducted using high temperature storage (HTS) at temperature of 150 °C and aging times of 200, 400, 600, 800, and 1000 h. IMC morphology and growth were examined using infinite focus microscope (IFM). Then, the SAC305 solder joint IMC growth kinetic was measured based on power law relationship and diffusion coefficient formula. It was noted that the morphology of IMC for the rougher Cu substrate has scallop-shaped and uniform layer as compared to that of smoother Cu substrate for the initial exposure to the HTS. In addition, Cu substrate with Ra of 579 nm is the turning point for the creation of Cu6Sn5 towards more Cu3Sn of IMC. In addition, Cu substrate with Ra of 579 nm also acts as the turning point for the IMC growth of SAC305 solder joint on Cu substrate for the solid-state diffusion to be happened during 150 °C of aging from grain boundary dominant toward volume diffusion dominant.

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