Defect Detection of Flip-Chip Solder Bump with Wavelet Analysis of Laser Ultrasound Signals

2006 ◽  
Author(s):  
Jin Yang ◽  
Lizheng Zhang ◽  
I.C. Ume
Keyword(s):  
Wavelet Analysis ◽  
Defect Detection ◽  
Flip Chip ◽  
Solder Bump ◽  
Laser Ultrasound ◽  
Ultrasound Signals

Defect Detection of Flip Chip Solder Bumps Through Local Temporal Coherence Analysis of Laser Ultrasound Signals

2007 ◽  
Author(s):  
Jin Yang ◽  
Charles Ume
Keyword(s):  
Defect Detection ◽  
Flip Chip ◽  
Solder Bump ◽  
Temporal Coherence ◽  
Coherence Analysis ◽  
Laser Ultrasound ◽  
Surface Mount ◽  
Flip Chips ◽  
Solder Bumps ◽  
Ultrasound Signals

Microelectronics packaging technology has evolved from through-hole and bulk configuration to surface-mount and small-profile ones. In surface mount packaging, such as flip chips, chip scale packages (CSP), and ball grid arrays (BGA), chips/packages are attached to the substrates or printed wiring boards (PWB) using solder bump interconnections. Solder bumps, which are hidden between the device and the substrate/board, are no longer visible for inspection. A novel solder bump inspection system has been developed using laser ultrasound and interferometric techniques. This system has been successfully applied to detect solder bump defects including missing, misaligned, open, and cracked solder bumps in flip chips, and chip scale packages. This system uses a pulsed Nd:YAG laser to induce ultrasound in the thermoelastic regime and the transient out-of-plane displacement response on the device surface is measured using the interferometric technique. In this paper, local temporal coherence (LTC) analysis of laser ultrasound signals is presented and compared to previous signal processing methods, including Error Ratio and Correlation Coefficient. The results show that local temporal coherence analysis increases measurement sensitivity for inspecting solder bumps in packaged electronic devices. Laser ultrasound inspection results are also compared with X-ray and C-mode Scanning Acoustic Microscopy (CSAM) results. In particular, this paper discusses defect detection for a 6.35mm×6.35mm×0.6mm PB18 flip chip and a flip chip (SiMAF) with 24 lead-free solder bumps. These two flip chip specimens are both non-underfilled.

Modal Analysis of Flip Chip for Solder Bump Defect Detection

2012 ◽  
Vol 468-471 ◽  
pp. 2104-2110
Author(s):  
Jun Chao Liu ◽  
Tie Lin Shi ◽  
Ke Wang ◽  
Miao Zeng ◽  
Guang Lan Liao
Keyword(s):  
Modal Analysis ◽  
Defect Detection ◽  
Flip Chip ◽  
Solder Bump ◽  
Ultrasonic Waves ◽  
Critical Element ◽  
Inspection Method ◽  
Chip Technology ◽  
Solder Bumps ◽  
Resonance Frequencies

Flip chip technology is one of the fastest growing segments of microelectronics packaging because of its ability to satisfy the increasing demands of high input/output density, package miniaturization, and reduced cost. A critical element in the successful application of flip chip technology is the reliability of solder bumps. In this paper, a nondestructive inspection method combining ultrasonic excitation with modal analysis is proposed for flip-chip solder bump defect detection. The signal generator and power amplifier are utilized to drive the capacitive air-coupled ultrasonic transducer to produce continuous ultrasonic waves for exciting the test chips. The vibration velocities of the chips are measured by the laser scanning vibrometer to extract the modal shapes and resonance frequencies. The results prove that the defective chips can be distinguished from the good chip by the modal shapes, and the resonance frequencies of the chips decrease with the increase of the open solder bumps. Therefore, this detection method may provide a new path for the improvement and innovation of flip chip on-line inspection systems.

The Use of Precision Selective Area Milling for Failure Analysis of Flip-Chip Packages

2002 ◽  
Author(s):  
George F. Gaut
Keyword(s):  
Failure Analysis ◽  
Flip Chip ◽  
Solder Bump ◽  
Selective Area ◽  
Fill Material ◽  
Solder Bumps ◽  
Time Required

Abstract Access to the solder bump and under-fill material of flip-chip devices has presented a new problem for failure analysts. The under-fill and solder bumps have also added a new source for failure causes. A new tool has become available that can reduce the time required to analyze this area of a flip-chip package. By using precision selective area milling it is possible to remove material (die or PCB) that will allow other tools to expose the source of the failure.

Precise Quantitative Evaluation of Nano-Ordered Intermetallic Compounds in Sn-3.0Ag-0.5Cu Lead-Free Solder Bump by Using TEM

2008 ◽  
Vol 47-50 ◽  
pp. 907-911
Author(s):  
Chang Woo Lee ◽  
Y.S. Shin ◽  
J.H. Kim
Keyword(s):  
Intermetallic Compounds ◽  
Flip Chip ◽  
Solder Bump ◽  
Lead Free Solder ◽  
Growth Behaviour ◽  
Sic Particles ◽  
Imcs Growth ◽  
Ordered Intermetallic ◽  
Free Solder ◽  
The One

The growth behaviour of the intermetallic compounds (IMCs) in Pb-free solder bump is investigated. The Pb-free micro-bump, Sn-50%Bi, was fabricated by binary electroplating for flip-chip bond. The diameter of the bump is about 506m and the height is about 60 6m. In order to increase the reliability of the bonding, it is necessary to protect the growth of the IMCs in interface between Cu pad and the solder bump. For control of IMCs growth, SiC particles were distributed in the micro-solder bump during electroplating. The thickness of the IMCs in the interface was estimated by FE-SEM, EDS, XRF and TEM. From the results, The IMCs were found as Cu6Sn5 and Cu3Sn. The thickness of the IMCs decreases with increase the amount of SiC particles until 4 g/cm2. The one candidate of the reasons is that the SiC particles could decrease the area which be reacted between the solder and Cu layer. And another candidate is that the particle can make to difficult inter-diffusion within the interface.

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