Development of a New Wire Bonding Technology on Integrated Circuit Devices

2009 ◽  
Author(s):  
Yingwei Jiang ◽  
Ronglu Sun ◽  
Sonder Wang ◽  
C. L. Zhang ◽  
Youmin Yu ◽  
...  
Keyword(s):  
Integrated Circuits ◽  
Copper Wire ◽  
Electrical Characterization ◽  
Wire Bonding ◽  
Bonding Process ◽  
Process Window ◽  
Temperature Cycle ◽  
Tool Selection ◽  
Bonding Technology ◽  
Gold Bump

In IC packaging, copper wire is generally regarded as a competent successor to gold wire due to many advantages in mechanical characteristics and cost efficiency. However, its known disadvantages restrict it to low-end integrated circuits as well. This paper discusses the development of a new wire bonding technology — copper ball on gold bump (COG) bonding in current wire bonders with both 1 mil copper and gold wires. It covers material and tool selection, wire bonding process window development, electrical characterization and reliability studies. The material and tool selection includes copper wire, experimental chip, capillary and wire bonder. Process window development focuses on two crucial stages, copper free air ball (FAB) formation and bonding process window development for both gold bump and copper ball bonded on Au bump. DOE approach is introduced into the relative process developments. The experimental studies reveal that flow rate of shielding gas is a key factor to obtain the qualified FAB formation and process window optimization for gold bump and copper ball on gold bump is more crucial to develop a successful COG bonding. Wire pull test, ball shear test and crater test are involved in the output measurement based on the criteria of JEDEC during the process window development. Package integrity and reliability performance with the COG bonding are fully assessed by performing electrical characterization and package internal delamination detection on the evaluated samples which have respectively undergone three reliability tests, High Temperature Baking, Temperature Cycle and Autoclave. The study result finally indicates that the COG bonding is a practicable approach to achieving copper wire application to high-end integrated circuits.

Development of 6mil Copper Wire Bonding for Replacing 10–15mil Aluminum Wire

2009 ◽  
Author(s):  
Yingwei Jiang ◽  
Ronglu Sun ◽  
Sonder Wang ◽  
Kenny Tan ◽  
Youmin Yu ◽  
...  
Keyword(s):  
Process Development ◽  
Copper Wire ◽  
Experimental Studies ◽  
Wire Bonding ◽  
Bonding Process ◽  
Process Window ◽  
Temperature Cycle ◽  
Tool Selection ◽  
Experimental Development ◽  
Ic Package

In IC package assembly, copper (Cu) wire bonding is a developing alternative interconnection technology for its advantages of more cost saving and better mechanical and electrical characteristics than gold (Au) and aluminum (Al) wires. This paper discusses experimental development of 6mil Cu wire bonding on ASM wire bonder to replace 15mil Al wire in a power IC package. It covers wire and tool selection, wire bonding process development, wire bonding integrity inspection and reliability study. The wire and tool selection includes wire type, capillary and wire bonder. The process development focuses on two crucial stages, Free Air Ball (FAB) formation and bonding process window development. DOE approach is introduced into the process development. The experimental studies show that flow rate of forming gas is a key factor to form the qualified FAB and a workable process window is established. Wire pull and ball shear tests are conducted to measure wire bonding strength of the built samples based on the criteria of JEDEC. Meanwhile, crater test and Zygo’s 3-D measurement are carried out to inspect any risk of underlying metal integrity in die before reliability tests. The data discloses that sufficient Al bond pad thickness is needed to avoid underlying metal damage during bonding process. The results of the two reliability tests, High Temperature Baking (HTB) and Pre-Condition (PC) & Temperature Cycle (TC), show that Cu/AL IMC growth is slow and accordingly lifetime of product may significantly extend. The overall result of the study finally indicates that with current thermosonic ball bonder, 6mil Cu wire is feasible to replace heavy 10–15mil Al wire in power package assembly.

Failure Analysis on Power Trench MOSFET Devices with Copper Wire Bonds

2011 ◽  
Author(s):  
Huixian Wu ◽  
Arthur Chiang ◽  
David Le ◽  
Win Pratchayakun
Keyword(s):  
Failure Analysis ◽  
Copper Wire ◽  
New Technology ◽  
Analytical Techniques ◽  
Wire Bonding ◽  
Bonding Process ◽  
Wire Bonds ◽  
Copper Wire Bonding ◽  
Wet Chemical ◽  
Microelectronic Components

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.

Electrical Failures Due to Particle Induced Copper Wire Bond Corrosion

2016 ◽  
Author(s):  
W.F. Kho ◽  
Gary H.G. Chan
Keyword(s):  
Integrated Circuits ◽  
Case Studies ◽  
Calcium Chloride ◽  
Copper Wire ◽  
Temperature Cycle ◽  
Reliability Test ◽  
Electrochemical Migration ◽  
Electrical Failure ◽  
Wire Bond ◽  
First Case

Abstract Contamination by particles is one of the major causes of failures in integrated circuits. In some cases, particles may absorb moisture leading to electrochemical migration, dendrite growth, and electrical leakage and short failures. This work presents two case studies of particle induced corrosion of copper wire bond that resulted in an electrical failure. In the first case, adjacent pin resistive short failures were found to fail due to corrosion and electrochemical migration at wires that were in contact with calcium chloride particles. Analysis showed that the highly hygroscopic calcium chloride particles absorbed moisture and resulted in corrosion and electrochemical migration of the copper wires. For the second case, an electrical open failure after temperature cycle reliability test was found to be due to an organophosphorus particle being in contact with the wire.

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