The Challenges of Fine Pitch Copper Wire Bonding in BGA packages

2006 ◽  
Author(s):  
Mohd Rusli Ibrahim ◽  
Yong Cheng Choi ◽  
Larry Lim ◽  
Jiang Lu ◽  
Low Teck Poh ◽  
...  
Keyword(s):  
Copper Wire ◽  
Wire Bonding ◽  
Bga Packages ◽  
Fine Pitch ◽  
Copper Wire Bonding

Fine pitch copper wire bonding on 45nm tech Cu/low-k chip with different bond pad metallurgy

2011 ◽  
Author(s):  
Leong Ching Wai ◽  
Norhanani Binte Jaafar ◽  
Michelle Chew ◽  
Sivakumar ◽  
Gunasekaran ◽  
...  
Keyword(s):  
Copper Wire ◽  
Wire Bonding ◽  
Fine Pitch ◽  
Copper Wire Bonding ◽  
Low K

Fine Pitch Cu Wire Bonding – As Good As Gold

2010 ◽  
Vol 2010 (1) ◽  
pp. 000650-000655
Author(s):  
Bernd K. Appelt ◽  
William T. Chen ◽  
Andy Tseng ◽  
Yi-Shao Lai
Keyword(s):  
Raw Materials ◽  
Copper Wire ◽  
Commodity Prices ◽  
Gold Wire ◽  
Wire Bonding ◽  
Fine Pitch ◽  
Methodical Approach ◽  
Copper Wire Bonding ◽  
Gold Wires ◽  
The Impact

Fine pitch wire bonding has traditionally been the domain of gold wires. The significant increase in gold commodity prices has driven a continuous reduction in wire diameters to minimize the impact of the raw materials cost of the wire. This has reached a point now where copper wires are beginning to displace gold wires despite the technical challenges associated with copper wires. The basic challenges like propensity for oxidation, hardness and propensity for corrosion can be managed with the appropriate investment in tooling and infrastructure. Doubts are persisting about yield and reliability. With a very methodical approach to developing the process controls, it can be demonstrated that yields are as good as those for gold despite the fact that copper bonds are not reworkable. Likewise, the typical JEDEC reliability tests can be full filled. Here, an extensive effort has been placed on extended JEDEC testing to demonstrate that with good process control and proper materials choices, test durations of more than 2x can be passed. This excellent performance demonstrates that copper wire bonding can be as good as or better than gold wire bonding.

Advancements in Silver Wire Bonding

2017 ◽  
Author(s):  
Subramani Manoharan ◽  
Chandradip Patel ◽  
Patrick McCluskey
Keyword(s):  
Failure Modes ◽  
Copper Wire ◽  
Gold Wire ◽  
Good Alternative ◽  
Wire Bonding ◽  
Silver Wire ◽  
Process Window ◽  
Fine Pitch ◽  
Wire Bonds ◽  
Copper Wire Bonding

Silver is a leading competitor to gold and copper in fine pitch wire bonding used in the interconnection of microelectronic devices. Primary material for wire bonding has been gold, which gave way to copper in order for original equipment manufacturers to realize cost benefits. However, copper wire bonding has exhibited several reliability issues, especially in industrial and high temperature applications. Corrosion is the major problem, which was mitigated by coating the wire with palladium, which increased overall cost of production. Other concerns include harder free air ball (FAB) leading to under pad metallization cracking, smaller process window, excessive aluminum splash especially in fine pitch bonding, and lower throughput and yield arising from the hardness and stiffness of copper. Due to the above concerns, automotive, military and aerospace industries are still reluctant to fully adopt copper wire bonding. Light emitting diodes (LEDs) are also not manufactured with copper wires due to its low reflectance. Some of these industries are still using gold wire bonds in most of their packages, but are continually looking for an alternative. Silver wire bonds have good electrical and thermal conductivity, are less prone to corrosion than copper, have low melting points and comparable hardness to gold. Also, cost of silver has been shown to be similar to that of palladium coated copper wire, hence making it a good alternative. Silver wire bonding, a relatively new area of research, has attracted a lot of research focused on wire dopant material, bonding process, quality and reliability. This paper is aimed to serve as a comprehensive review of research done in this area, by summarizing the literature on silver wire bonding, establishing benefits and drawbacks over other wire bond materials and indicating reliability concerns along with failure modes and mechanisms.

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