Failure Analysis on Low Pull Strength of Thermo-sonic Wedge Bond between Gold Wire and Gold Substrate of MEMS Device

2007 ◽  
Author(s):  
Sanjay Kumar Thakur ◽  
Gan Tai Kwee
Keyword(s):  
Failure Analysis ◽  
Gold Wire ◽  
Gold Substrate ◽  
Pull Strength ◽  
Mems Device

Evaluation of Secondary Wire Bond Integrity on Ag Plated and Ni/Pd Based Lead Frame Plating Finishes

2009 ◽  
Author(s):  
G. Srinivasan ◽  
R. Murcko ◽  
K. Srihari
Keyword(s):  
High Temperature ◽  
Failure Analysis ◽  
Wire Bonding ◽  
Strength Test ◽  
Lead Frame ◽  
Wire Bond ◽  
Pull Strength ◽  
High Temperature Storage ◽  
The Wire ◽  
Temperature Storage

As the legislatures demand the use of lead (Pb) free plating finishes in lead frame manufacturing, different plating finishes are being offered by the lead frame makers. Lead frames are most often designed with two different Pb free plating finishes, primarily tin and nickel/palladium (Ni/Pd) based. The tin post mold plated lead frames use silver selective plating on the lead fingers for secondary wire bonding whereas the pre-plated Ni/Pd based lead frames use the same Ni/Pd based finish throughout. Enhanced versions of Ni/Pd based plating finishes such as nickel/palladium/gold (Ni/Pd/Au), nickel/palladium/gold-palladium (Ni/Pd/Au-Pd) and nickel/palladium/gold-silver (Ni/Pd/Au – Ag) are now available to further improve the wirebondability, solderability and reliability of the package. The development of a new lead frame finish involves a wide variety of concerns which must be addressed and thus mandates further evaluation of these new structures. Using the common Pb free lead frame plating finish of selectively plated silver (Ag) as the basis, a comparative approach was used to evaluate the secondary wire bond integrity of a 25 micron (1 mil) thick gold wire on Ni/Pd based lead frame plating finishes. The integrity of the secondary wire bonds for different plating finishes was investigated at various assembly thermal exposure stages using the wire pull strength test as the arbiter. Reliability tests, such as High Temperature Storage (HTS) and Unbiased Highly Accelerated Stress Test (UBHAST), were also conducted. Finally, failure analysis was conducted with the help of metallographic cross sectioning, SEM/EDX (Scanning Electron Microscope/Energy Dispersive X-ray) analysis and statistical analysis of the wire pull strength test results. Before wire bonding the lead frames, the plating surface was investigated for its surface integrity with the help of plating quality tests, such as: (i) adhesive tape test, (ii) bend test, (iii) heating test and the (iv) scribing test. Also, since wire pull is a destructive test, a statistical method called a nested gauge R&R study was used to estimate the repeatability and reproducibility of the measurement system. Failure analysis showed that there were silver and copper migrations over the Ag plated lead frame when exposed to a high temperature storage test at 175°C for 1000 hrs, but this did not affect the bond integrity. However, the Ni/Pd based lead frames did not show any metal migration since nickel acts as a barrier against the base metal diffusion.

Effect of Ca Content on Mechanical Properties of 4N Gold Wire for Quad Flat Nolead (QFN) Stacked Die Package

2010 ◽  
Vol 97-101 ◽  
pp. 36-39
Author(s):  
Azman Jalar ◽  
Saidatul Azura Radzi ◽  
Muhammad Azmi Abd Hamid
Keyword(s):  
Mechanical Properties ◽  
Trace Elements ◽  
Gold Wire ◽  
Wire Bonding ◽  
Strength Increase ◽  
Element Analysis ◽  
Bonding Material ◽  
Pull Strength ◽  
Fine Pitch ◽  
Automatic Wire

This paper discusses the effect of two similar gold wire (wire A and wire B) used mainly as a wire bonding material for Quad Flat Nolead (QFN) package. Both wires with diameter of 25.4 μm were bonded using automatic wire bonder by maintaining the temperature at 200°C. The effect of trace elements on the mechanical properties of 4N gold wire has not been widely investigated for some years despite the important of wire-bonding and the move towards fine pitch applications. Due to the element analysis, atomic percentage of Ca in wire B is higher than wire A. Pull strength increase with the increasing of the trace element. The higher pull strength of wire B could improve the yield strength, elastic modulus and recrytallization temperature.

A Novel Non-Destructive Approach to Deprocess the Sealing Cap from MEMS Device for Failure Analysis

2010 ◽  
Author(s):  
Hsien-Wen Liu ◽  
King-Ting Chiang ◽  
Tao-Chi Liu ◽  
Ming-Lun Chang ◽  
Jandel Lin
Keyword(s):  
Failure Analysis ◽  
Failure Modes ◽  
Ex Situ ◽  
Mems Devices ◽  
Mems Sensors ◽  
Micro Electro Mechanical Systems ◽  
New Approach ◽  
Wet Chemical ◽  
Mems Device ◽  
Non Destructive

Abstract Applications of Micro-Electro-Mechanical Systems (MEMS) sensors have developed rapidly in the last decade, increasing the need of Failure Analysis (FA) to characterize abnormalities and to identify failure modes of various types of MEMS devices. One of the greatest challenges is removal of the sealing cap from the MEMS device without any impact to the moveable sensing elements. A novel non-destructive technique has been successfully developed using KOH wet chemical etching followed by application of ex-situ hand sticking to deprocess the sealing cap from an accelerometer device. This new approach provides a quick and reliable way to remove the sealing cap from a MEMS device.

Failure Analysis With the Scanning Electron Microscope

1972 ◽  
Vol 30 ◽  
pp. 482-483
Author(s):  
John R. Devaney
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Integrated Circuits ◽  
Failure Analysis ◽  
High Reliability ◽  
Military Applications ◽  
Small Structure ◽  
Useful Life ◽  
Insight Into ◽  
Scanning Electron

Occasionally in history, an event may occur which has a profound influence on a technology. Such an event occurred when the scanning electron microscope became commercially available to industry in the mid 60's. Semiconductors were being increasingly used in high-reliability space and military applications both because of their small volume but, also, because of their inherent reliability. However, they did fail, both early in life and sometimes in middle or old age. Why they failed and how to prevent failure or prolong “useful life” was a worry which resulted in a blossoming of sophisticated failure analysis laboratories across the country. By 1966, the ability to build small structure integrated circuits was forging well ahead of techniques available to dissect and analyze these same failures. The arrival of the scanning electron microscope gave these analysts a new insight into failure mechanisms.

Using the scanning electron microscope for failure analysis of high density magnetic media

1987 ◽  
Vol 45 ◽  
pp. 392-393
Author(s):  
Evelyn R. Ackerman ◽  
Gary D. Burnett
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Failure Analysis ◽  
High Density ◽  
Magnetic Media ◽  
Specific Data ◽  
Retrieval Systems ◽  
Operating Environments ◽  
The Media ◽  
Scanning Electron

Advancements in state of the art high density Head/Disk retrieval systems has increased the demand for sophisticated failure analysis methods. From 1968 to 1974 the emphasis was on the number of tracks per inch. (TPI) ranging from 100 to 400 as summarized in Table 1. This emphasis shifted with the increase in densities to include the number of bits per inch (BPI). A bit is formed by magnetizing the Fe203 particles of the media in one direction and allowing magnetic heads to recognize specific data patterns. From 1977 to 1986 the tracks per inch increased from 470 to 1400 corresponding to an increase from 6300 to 10,800 bits per inch respectively. Due to the reduction in the bit and track sizes, build and operating environments of systems have become critical factors in media reliability.Using the Ferrofluid pattern developing technique, the scanning electron microscope can be a valuable diagnostic tool in the examination of failure sites on disks.

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