Joint reliability evaluation of thermo-compression bonded FPCB/RPCB joints under high temperature storage test

2013 ◽  
Vol 53 (12) ◽  
pp. 2036-2042 ◽  
Author(s):  
Jeong-Won Yoon ◽  
Min-Kwan Ko ◽  
Bo-In Noh ◽  
Seung-Boo Jung
Keyword(s):  
High Temperature ◽  
Reliability Evaluation ◽  
Storage Test ◽  
Joint Reliability ◽  
High Temperature Storage ◽  
Temperature Storage

Copper Ball Voids: Failure Mechanisms and Methods of Controlling at High Temperature Automotive Application

2019 ◽  
Vol 2019 (DPC) ◽  
pp. 000519-000530
Author(s):  
Chu-Chung Lee ◽  
TuAnh Tran ◽  
Varughese Mathew ◽  
Rusli Ibrahim ◽  
Poh-Leng Eu
Keyword(s):  
High Temperature ◽  
Void Formation ◽  
High Volume ◽  
Automotive Application ◽  
Corrosion Mechanism ◽  
Adhesion Promoter ◽  
Storage Test ◽  
Ball Bond ◽  
High Temperature Storage ◽  
Temperature Storage

Since 2008, fine gauge (≤ 35 μm diameter) copper (Cu) wire has been rapidly replacing fine gauge gold (Au) wire in consumer, commercial, and industrial products [2–4]. The first wave of Cu wire products used bare, uncoated Cu wire which is soon to known having Cu-Al IMC corrosion induced by mobile chlorine ions in the epoxy mold compound system when IC parts are subjected to moisture related package stress tests such as biased HAST (Highly Accelerated Stress Test) [1–7]. Additionally, when comparing to Au wires, the 2nd bond process window of bare Cu wire can be very narrow and becomes a concern of moving into HVM (high volume manufacturing) [8]. Thus, palladium-coated Cu (PdCu) wire was introduced to the semiconductor assembly market aiming to provide more margin of passing biased HAST and enhance 2nd bond process capability [9–13]. However, the use of Pd-Cu wire is not a panacea to all Cu wire bond problems. One unique anomaly for Pd-Cu wire is the Cu ball void [1] which is observed only with Pd-Cu and not bare Cu ball bonds during HTSL (high temperature storage life) tests. The mechanism of forming Cu ball voids was proven to be the galvanized corrosion mechanism with Pd-Cu coupling. Significant factors affecting the formation rate of Cu ball voids are found to be baking temperature, EFO current settings, bonding parameters and mold compound additives (sulfur). Both anodic and cathodic chemical reactions will be proposed for Cu voids in this paper. Even though Cu void can be considered as a cosmetic defect for the majority of application since the peak temperature of device mission profile is always no larger than 175C. The application at extreme high temperature (for example, 190C) can actually cause electrical failure at the ball bon region due to the Cu void formation in terms of size and location at the Cu-Al IMC region. The main effect is due to the selected mold compound having high amount of metallic adhesion promoter which is sulfur-based and extensive high temperature storage test condition (190C). The FIB/SEM picture of failing ball bond due to Cu voids from this particular device will be presented in the paper. Thus, a newly developed doped Cu wire without Pd coating has been proposed by many wire suppliers to overcome Cu ball voids. However, doped Cu wires without Pd coating have suffered the same high volume manufacturing issues observed by bare Cu wires. For example, short tail and mean time between assist (MTBA) for doped Cu wires without Pd coating are both as poor as bare Cu wires. We will present high temperature storage test results obtained by doped PdCu wires in this paper. To balance high volume manufacturing issues and Cu void formation, doped PdCu wires are also proposed recently. Several doped PdCu wires whose extensive high temperature storage results (220C) will be presented in this paper. The worst case mold compound with high amount of sulfur based adhesion promoter has been used to test the effectiveness of these new wire types. At such harsh testing condition, there is one doped PdCu wire in our test can actually survive without electrical failed ball bond due to Cu voids. Factors of effectiveness of doped PdCu wires will be discussed in this paper. Authors have chosen to focus on Cu voids at both 1st bond (ball bond) and 2nd bond (wedge). 20 um wire diameter has been used for all test vehicle in this study. All controlling factors of eliminating Cu voids will surely be included at the end of this paper.

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.

Stability Investigation of High Heat-Resistant Resin under High Temperature for Ultra-High Blocking Voltage SiC Devices

2013 ◽  
Vol 740-742 ◽  
pp. 669-672 ◽  
Author(s):  
Toru Izumi ◽  
Tetsuro Hemmi ◽  
Toshihiko Hayashi ◽  
Katsunori Asano
Keyword(s):  
High Temperature ◽  
Linear Thermal Expansion ◽  
High Heat ◽  
Storage Test ◽  
Heat Resistant ◽  
Blocking Voltage ◽  
High Temperature Storage ◽  
Higher Temperature ◽  
Insulation Performance ◽  
Temperature Storage

The reliability of three kinds of high heat-resistant resins has been evaluated under high temperatures. These resins were applied to insulation substrates and a high temperature storage test has been carried out. The insulation performance of the resins was evaluated by applying 20 kV between a pair of electrodes on the substrate covered with resin. The insulation performance at 20 kV was maintained in samples with two of the three kinds of resins for 1,000 hours at 225oC. In a higher temperature storage test at 250oC, samples with one of the kinds of resin were not able to maintain insulation of 20 kV for 200 hours, while the two remaining resins were not able to maintain the insulation for 1,000 hours. In most samples that were not able to maintain the insulation, cracks or detachments were seen. Hardening caused by oxidation of the resin and differences in the coefficient of linear thermal expansion (CTE) are considered as causes of the cracks or detachments. It is thought to be necessary to lower the CTE of the resin and inhibit its oxidation in order to use it at more than 250oC for long periods of time.

Failure Analysis of the Die-Attach in a Metal-Type Package

1996 ◽  
Author(s):  
J. Acki ◽  
A. Murakami ◽  
T. Akutsu ◽  
S. Matsuda ◽  
A. Maruyama ◽  
...  
Keyword(s):  
High Temperature ◽  
Alloy Layer ◽  
Storage Test ◽  
Power Mosfet ◽  
Package Design ◽  
Die Attach ◽  
Metal Type ◽  
High Temperature Storage ◽  
Space Projects ◽  
Temperature Storage

Abstract RECENTLY POWER MOSFETS have been used for satellite power supplies. NASDA has developed such a Power MOSFET for the space projects. It has a metal-type package, and the die is attached by Au-Si alloy to achieve high temperature operation (Tj=200°C). The fabricated device failure was detected thermal resistance tests after high temperature storage test at 200°C for 1000 hours. This failure is caused by the die peeling between the Au-Si eutectic alloy layer and the Ni plating surface on the Cu-W substrate. In this paper, we describe the failure mechanism and improvements in the package design and fabrication process. The newly developed power MOSFET for space use exhibits good performance in the high temperature storage test.

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