Fine pitch copper wire bonding in high volume production

2011 ◽  
Vol 51 (1) ◽  
pp. 13-20 ◽  
Author(s):  
Bernd K. Appelt ◽  
Andy Tseng ◽  
Chun-Hsiung Chen ◽  
Yi-Shao Lai
Keyword(s):  
Copper Wire ◽  
High Volume ◽  
Wire Bonding ◽  
Fine Pitch ◽  
Copper Wire Bonding ◽  
High Volume Production ◽  
Volume Production

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.

Copper Wire Bonding: R&D to High Volume Manufacturing

2012 ◽  
Vol 2012 (1) ◽  
pp. 000638-000649 ◽  
Author(s):  
Bob Chylak ◽  
Horst Clauberg ◽  
John Foley ◽  
Ivy Qin
Keyword(s):  
Copper Wire ◽  
Leading Edge ◽  
Relative Sensitivity ◽  
High Volume ◽  
Gold Wire ◽  
Wire Bonding ◽  
Bonding Process ◽  
Wire Diameter ◽  
Bond Quality ◽  
Copper Wire Bonding

During the past two years copper wire bonding has entered high volume manufacturing at a number of leading edge OSATs and IDMs. Usage of copper wire has achieved 20% market share and is expected to exceed 50% within three years. Products spanning the range from low pin count devices with relatively large wire diameter to FPGA's with nearly one thousand wires at 20 μm or even 18 μm wire are now using copper wire. This paper will discuss the requirements for developing a robust copper wire bonding process and then moving it to high volume manufacturing. Process optimization begins with the selection of the appropriate wire diameter, ball diameter, bonding tool and bonding process type. These are functions not only of the bond pad opening, but also of the pad aluminum thickness and relative sensitivity of the pad to damage. Proper optimization depends on the availability of new and modified bond quality metrologies, such as extensive reliance on cross-sectioning and intermetallic coverage measurements. The bonding window of a copper wire bonding process is defined in substantially new terms compared to optimization in gold wire bonding. Once an optimized process has been developed in the lab on a single bonder, it needs to be verified. Copper wire bond processes are much less forgiving with respect to the acceptable variability on the manufacturing floor. To ensure that the process is stable, a low volume pre-manufacturing test is highly recommended. This not only makes sure that the process is stable across multiple bonders, but also ensures the adequacies of manufacturing controls, incoming materials quality and sufficient equipment calibration and maintenance procedures.

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