Advances in Wire Bonding Technology for Overhang Applications

2016 ◽  
Vol 2016 (1) ◽  
pp. 000456-000462 ◽  
Author(s):  
Aashish Shah ◽  
Gary Schulze ◽  
Nestor Mendoza ◽  
J.H. Yang ◽  
Rob Ellenberg ◽  
...  

Abstract Wire bonding is the most popular interconnect technology and the workhorse of the semiconductor packaging industry. Wire bonding is widely used for 3D packaging in which multiple dies are often stacked vertically in a ‘stacked die’ configuration. In such packages, one or more dies may be unsupported in an ‘overhang’ (e.g. cantilever beam) configuration. Wire bonding on an overhang die causes die deflection. If not optimized, it may lead to improper ball shape, inconsistent looping, pad crack and die crack issues. Therefore, careful process optimization is needed to have the best outcome in wire bonding performance. This optimization is often tedious and time-consuming. Moreover, recent trends towards minimizing package size (e.g. ultra-thin dies) and increasing number of die stacks add to the challenges of optimizing a wire bonding process for overhang devices. This paper examines the challenges of wire bonding on overhang devices. Finite element analysis (FEA) of overhang devices is presented. Die deflection data obtained from the FEA correlates well with the experimental results obtained on the ball bonder. The FEA results show that die deflection increases significantly with decreasing die thickness and increasing overhang distance. Other factors such as substrate thickness, and bonding temperature also effect die deflection, although less significantly than die thickness and overhang distance. Various considerations for optimizing a ball bonding process on overhang devices are discussed. Experimental results of ball bonding optimization on 50 μm and 75 μm thick overhang devices with different overhang configurations are presented.

2014 ◽  
Vol 609-610 ◽  
pp. 1153-1158
Author(s):  
Dong Rui Wang ◽  
Mei Liu

The wire bonding process in the package of MEMS accelerometer is analyzed by the finite element software ANSYS/LS-DYNA. Impact on the bonding strength of the ultrasonic amplitude, ultrasonic frequency and the friction between wire bond and bond pad are studied. The strength of wire bond is evaluated through the bond pull test experiment. The test result shows that the analysis on the wire bonding is helpful for improving the quality of wire bonding.


Author(s):  
Li Jia ◽  
Guo Hao ◽  
Guo Zhiping ◽  
Miao Shujing ◽  
Wang Jingxiang

<p>By MEMS packaging test platform for bonding process of bonding temperature and bonding time, and test silicon specifications experimental study. Experimental results indicate that when the bonding voltage of 1200V, bonding temperature of 445<sup>0</sup>C to 455<sup>0</sup>C, bonding time is 60s,the void fraction is less than 5%.Glass and silicon wafer bonding quality can achieve the best. The experimental results in order to improve the glass silicon bonding quality provide the basis.</p>


2020 ◽  
Vol 142 (2) ◽  
Author(s):  
Wan-Chun Chuang ◽  
Wei-Long Chen

Abstract This study successfully established a strip warpage simulation model that is applied to the wire bonding process, and explored the effects of structural designs, material types, and processes such as molding, post and mold cure (PMC), pretreatment, and ball mounts on the strip warpage. The error between the experimental values and the simulation values is less than 13.7%. In addition, the Taguchi method is used to determine that the key factors affecting the strip warpage are the die thickness and the mold compound thickness, and that the secondary key factor is the molding temperature. This study concluded that in order to reduce strip warpage, the die thickness must be increased, while the compound thickness and the molding temperature must be decreased. To solve this problem, the structural design criteria proposed in this study use a smaller distance ratio of the neutral axis of the strip (zn) to the dice centroid (zdie). With this modification, it can reduce warpage and overall thickness of the strip. These observations indicate that the proposed model can be used to understand the effects of structural design, material types, and process parameter changes on the strip warpage. Strip design criteria are also provided in order to reduce the strip warpage, and thus, meet the requirement of thin and compact production lines, accelerate product development cycles, improve product quality, and reduce development costs.


1998 ◽  
Vol 26 (2) ◽  
pp. 109-119 ◽  
Author(s):  
M. Koishi ◽  
K. Kabe ◽  
M. Shiratori

Abstract The finite element method has been used widely in tire engineering. Most tire simulations using the finite element method are static analyses, because tires are very complex nonlinear structures. Recently, transient phenomena have been studied with explicit finite element analysis codes. In this paper, the authors demonstrate the feasibility of tire cornering simulation using an explicit finite element code, PAM-SHOCK. First, we propose the cornering simulation using the explicit finite element analysis code. To demonstrate the efficiency of the proposed simulation, computed cornering forces for a 175SR14 tire are compared with experimental results from an MTS Flat-Trac Tire Test System. The computed cornering forces agree well with experimental results. After that, parametric studies are conducted by using the proposed simulation.


Author(s):  
Huixian Wu ◽  
Arthur Chiang ◽  
David Le ◽  
Win Pratchayakun

Abstract With gold prices steadily going up in recent years, copper wire has gained popularity as a means to reduce cost of manufacturing microelectronic components. Performance tradeoff aside, there is an urgent need to thoroughly study the new technology to allay any fear of reliability compromise. Evaluation and optimization of copper wire bonding process is critical. In this paper, novel failure analysis and analytical techniques are applied to the evaluation of copper wire bonding process. Several FA/analytical techniques and FA procedures will be discussed in detail, including novel laser/chemical/plasma decapsulation, FIB, wet chemical etching, reactive ion etching (RIE), cross-section, CSAM, SEM, EDS, and a combination of these techniques. Two case studies will be given to demonstrate the use of these techniques in copper wire bonded devices.


Author(s):  
Brian D. Sosnowchik ◽  
Liwei Lin ◽  
Albert P. Pisano

In this work, we present a rapid, low temperature process for the bonding of silicon to steel through the use of inductive heating for MEMS sensor applications. The bonding process takes as short as three seconds with a maximum bonding temperature as low as 230°C at the steel surface. The bonding strength is strong, and causes minimal damage to steel. The process has also been shown to work using leaded and leadfree bonding solder with minimal surface preparation to the steel. Four characterization experiments – tensile and compressive 4-point bend, axial extension, and fatigue tests – have been performed to validate the bonding process and materials. As such, this work illustrates the promise of applying inductive heating for the rapid silicon bonding to steel components for MEMS sensing applications.


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