F29 Monitoring Solder Bump Composition on C4 Flip Chip Process Line for the Semiconductor Packaging Industry

2003 ◽  
Vol 18 (2) ◽  
pp. 182-182
Author(s):  
T. He
Author(s):  
Kaustubh Nagarkar ◽  
Tan Zhang ◽  
David Esler ◽  
David Simon ◽  
Paul Gillespie ◽  
...  

Flip chip packaging is one of the fastest growing segments in electronics packaging technology. The semiconductor packaging industry is continuing to migrate towards Pb-free electronics assembly. Therefore, the development of compatible materials for Pb-free flip chip packaging is critical to this transition [1]. Flip chip devices are commonly underfilled to compensate for the mismatch in the Coefficient of Thermal Expansion (CTE) between the die and the chip carrier. The No Flow Underfill (NFU) process is a type that can increase the throughput of the flip chip assembly process and reduce manufacturing costs. Significant research has been performed to develop NFUs for eutectic applications. However, further research is required for the development of NFUs that are compatible with the Pb-free solders and the high temperature reflow process associated with these solders. In this paper, the challenges associated with the development of 'filled' underfill formulations for assembly with the 95.5Sn/3.8Ag/0.7Cu bumped flip chip devices are discussed. The effects of process variables that affect voiding in the underfill layer have been presented. The impact on voiding due to stencil printing of the underfill has been discussed. The impact on assembly reliability due to the underfill material properties has also been reported.


Author(s):  
George F. Gaut

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.


Author(s):  
Jin Yang ◽  
Charles Ume

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.


2008 ◽  
Vol 47-50 ◽  
pp. 907-911
Author(s):  
Chang Woo Lee ◽  
Y.S. Shin ◽  
J.H. Kim

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.


2020 ◽  
Vol 9 (2) ◽  
pp. 98-131
Author(s):  
Liang-Hsuan Chen ◽  
Chia-Jung Chang

For some quality inspection practices, subjective judgements based on the inspectors' experience and knowledge, such as visual inspection, may be required for some particular quality characteristics. This kind of measurement system, including its associated randomness and fuzziness, should be assessed by Measurement system analysis (MSA) before its application. For such purpose, this article represents observations with randomness and fuzziness from MSAs as fuzzy random variables, and then two pairs of descriptive parameters, i.e., expected value and variance, are derived. Then, the relationship of the total sum of squares of factors is proven to hold, so that fuzzy analysis of variance (FANOVA) in terms of gauge repeatability and reproducibility can be developed. The proposed approach has the advantage that FANOVA is developed based on the relationship of the total sum of squares of factors, considering randomness and fuzziness. A real case in the semiconductor packaging industry is used to demonstrate the applicability of the proposed approaches to MSA.


2011 ◽  
Vol 2011 (1) ◽  
pp. 000008-000016 ◽  
Author(s):  
Antonio La Manna ◽  
K. J. Rebibis ◽  
C. Gerets ◽  
E. Beyne

A key element for improving 3D stacking reliability is the choice of the right Underfill materials. The Underfill is a specialized adhesive that has the main purposes of locking top and bottom dies; it must fill the gap between bumps and between dies, while reducing the differential movement that would occur during thermal cycling. Traditional underfill processes are based on local dispensing after solder bump reflow (Capillary dispensing), or before flip chip operation with no need of reflow (No Flow Underfill, NUF). In case of 3D stacking, such processes present some limitations: need of a dispensing area (die size increase); material flowing (spacing between dies) and cost (low throughput). After an introduction on typical underfill applications like die-to-package and die-die assembly, we report the work done to assess the properties of several Wafer Applied Underfill (WAUF) materials and their integration in 3D stacking. These materials have been initially applied on silicon wafers in order to assess the minimum achievable thickness and the material uniformity. The wafers have been coated by using different methods: spin coating and film lamination. After this initial assessment, the most promising materials have been used for 3D stacking. The test vehicle used has Cu/Sn μbumps with a pitch of 40μm. The quality of the materials is judged by electrical test, SAM (Surface Acoustic Microscope) and X-SEM (Scanning Electron Microscope).


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