Corrosion of Gold and Copper Ball Bonds

2019 ◽  
Vol 34 (1) ◽  
pp. 831-841
Author(s):  
Christopher D. Breach ◽  
Hun Shen Ng ◽  
Teck Kheng Lee ◽  
Richard Holliday
Keyword(s):  
Ball Bonds

Partial diffusion reactions and the associated volume changes in thermally exposed Au-Al ball bonds

2004 ◽  
Vol 35 (4) ◽  
pp. 1273-1280 ◽  
Author(s):  
Naren J. Noolu ◽  
Nikhil M. Murdeshwar ◽  
Kevin J. Ely ◽  
John C. Lippold ◽  
William A. Baeslack
Keyword(s):  
Volume Changes ◽  
Ball Bonds

High Temperature Storage Reliability of Bond Resistance of Palladium-Coated Copper Ball Bonds

2017 ◽  
Vol 2017 (1) ◽  
pp. 000432-000437 ◽  
Author(s):  
Michael David Hook ◽  
Michael Mayer ◽  
Stevan Hunter
Keyword(s):  
High Temperature ◽  
Ball Bond ◽  
Wire Bonds ◽  
High Temperature Storage ◽  
Ball Bonding ◽  
Ball Bonds ◽  
Bond Pads ◽  
Wire Resistance ◽  
Temperature Storage

Abstract Reliability of wire bonds made with palladium-coated copper (PCC) wire of 25 μm diameter is studied by measuring the wire bond resistance increase over time in high temperature storage at 225 °C. Ball bonds are made on two bond pad thicknesses and tested with and without mold compound encapsulation. Bond pads are aluminum copper (Al-0.5%Cu), 800 nm and 3000 nm thick. The wirebonding pattern is arranged to facilitate 4-wire resistance measurements of 12 bond pairs in each 28-pin ceramic test package. The ball bonding recipe is optimized to minimize splash on 3000 nm Al-0.5%Cu with shear strength at least 120 MPa. Ball bond diameter is 61 μm and height is 14 μm. Measurements include bond shear test data and in-situ resistance before and during high temperature storage. Bonds on 3000 nm pads are found to be significantly more reliable than bonds on 800 nm pads within 140 h of aging.

Reliability of Coated and Alloyed Copper/Silver Ball Bonds

2017 ◽  
Vol 2017 (1) ◽  
pp. 000318-000324 ◽  
Author(s):  
Sarangapani Murali ◽  
Bayaras Abito Danila ◽  
Zhang Xi
Keyword(s):  
Electrical Resistance ◽  
Stress Test ◽  
Thermal Ageing ◽  
Epoxy Compound ◽  
Resistance Test ◽  
Ball Size ◽  
Green Mold ◽  
Wire Bonds ◽  
Ball Bonds

Abstract The paper discusses on the reliability of coated and alloyed copper/silver ball bonds on both epoxy molded and unmolded conditions:Moisture resistance test using unmolded device at 130°C 85%RH (humidity chamber) revealed no ball lift failure until 96hours for the ball size of 1.65 times the diameter of wireCorrosion resistance test using unmolded device at room temperature by dripping (or soaking) dilute chlorine (Cl) solution revealed no ball lift failure for gold wires. Copper base wire bonds failed after 6min of storage while silver (Ag) base wire bonds showed a few bond lifts within 2min. This shows that Ag base wires are more sensitive to Cl environment than copper (Cu) base wiresA case study of epoxy molded device using green mold compound and four types of Cu and Ag base ball bonds passed on thermal ageing (HTS) at 175°C for 4000h and on +5V bHAST for 500h. The test response is by measuring electrical resistance in order not to reduce below 10% of contact resistance measured during time zero bonding○ Cross-section analysis of the samples showed intact bonding of Cu and Ag base ball bonds after 4000h of HTS○ The result shows when Cu and Ag base wire bonds molded with a good compatible green mold epoxy compound satisfy the automotive electronic council (AEC – Q006 & Q100 Rev-H, for Cu) requirements of 2X stress test with respect to electrical resistance measurementAnother case study of epoxy molded device revealed Cu and Ag base wire bonds pass 3000cycles of thermal cycling (−55°C to +150°C) without any neck/heel cracks and stitch lifts In addition, fine wires are baked at elevated temperature under vacuum or by purging nitrogen to find the quality of wire surface. As expected, Au, Cu and Ag base wires show clean surface. For palladium (Pd) coated Cu wire, a good Pd adhesion to Cu core surface without blisters is evident.

Effects of Probe Marks on Shear Test of Copper Ball Bonds in Two Pad Aluminum Thicknesses

2016 ◽  
Vol 2016 (1) ◽  
pp. 000219-000226 ◽  
Author(s):  
Priscila Brown ◽  
Rachel Wynder ◽  
Dustin Tenney ◽  
Stevan Hunter
Keyword(s):  
Image Analysis ◽  
Shear Force ◽  
Shear Test ◽  
Physical Factors ◽  
Microscopic Image ◽  
Test Results ◽  
Contact Areas ◽  
Ball Bonds ◽  
Optical Microscopic Image ◽  
Bond Pads

Abstract This paper continues the work of reference [1], evaluating shear test results of Cu ball bonds over a variety of probe marks in two different pad aluminum (Al) thicknesses (0.8μm and 3μm). The presence of invasive probe marks on thick Al bond pads lowers certain shear force results.. Lower values of shear force imply reduced Cu bond reliability. Physical factors are investigated relating to poor intermetallic (IMC) formation in the Cu wirebond and bond shear force. Optical microscopic image analysis of Cu bonds, bond contact areas and Al “splash” are studied for correlation with the shear test results. Percent IMC coverage of bond contact areas decrease when invasive probe marks are present beneath the bond, which in turn may reduce the shear force. Probe mark features are studied to discover the characteristics of greatest influence on % IMC coverage and shear test values in each of the pad metal thicknesses.

Assessment of 20 Micrometer Diameter Wires for Wire Bond Interconnect Technology

2007 ◽  
Author(s):  
S. Saiyed ◽  
S. A. Kudtarkar ◽  
R. Murcko ◽  
K. Srihari
Keyword(s):  
High Temperature ◽  
Stress Test ◽  
Small Diameter ◽  
Mechanical Tests ◽  
Stress Tests ◽  
Bonding Wire ◽  
Chip Area ◽  
Wire Bond ◽  
Ball Bonds ◽  
The Wire

In the domain of wire bonding technology, the size and pitch of bond pads and ball bonds are shrinking to accommodate the demand for higher I/Os and increased functionality per chip area. This trend serves as a catalyst for bonding wire manufacturers to continuously develop lower diameter bonding wires. One mil (25 μm) diameter bonding wire, used widely in this interconnection technique, is now being replaced by 0.8 mil (20 μm) diameter bonding wire. In keeping with the need for higher operating speeds and higher temperatures for today’s ICs, the reliability of ball bonds formed by small diameter wires is of concern and requires investigation. This study explores the effects of 0.8 mil (20 μm) diameter bonding wire on the wire bond ball joint reliability and compares these effects with 1.0 mil (25 μm) diameter bonding wire. The reliability of the ball bonds was assessed using mechanical tests (wire pull and ball shear) for units subjected to stress tests such as the unbiased highly accelerated stress test and high temperature storage tests. The results of this investigation reveal that both the wire diameters are able to sustain their integrity after moisture testing. But, the bond strength degrades after high temperature tests due to the Kirkendall voiding mechanism occurring between gold wire and the aluminum bond pad.

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