Solder Joining Technology

1989 ◽  
Vol 154 ◽  
Author(s):  
Nick Koopman
Keyword(s):  
Flip Chip ◽  
Materials Design ◽  
Wire Bonding ◽  
Future Trends ◽  
Joining Technology ◽  
Solder Bumps ◽  
Design Factors

An in-depth review of controlled collapse chip connections (c-4), or otherwise known as Flip Chip Solder Joining Technology, is present. The C4 joint utilizes solder bumps deposited on wettable terminals on the chip and a matching footprint of the substrate. The upsidedown chip (flip chip) is aligned to the substrate and all joints are made simultaneously by reflowing the solder. An in depth review of this technology is presented. Materials, design factors, fabrication processes, tools, assembly, rework, and reliability are discussed. Future trends are indicated and comparisons make with wire bonding and Tab (tape automated bonding).

A cost effective PoP structure with high I/O density

2014 ◽  
Vol 2014 (DPC) ◽  
pp. 000768-000785
Author(s):  
Hongjie Wang ◽  
Weidong Huang ◽  
Fei Geng ◽  
Yuan Lu ◽  
Bo Zhang ◽  
...  
Keyword(s):  
Solder Ball ◽  
Flip Chip ◽  
Solder Bump ◽  
Cost Effective ◽  
Wire Bonding ◽  
Manufacturing Cost ◽  
Good Reliability ◽  
Solder Bumps ◽  
Package Size ◽  
Interconnection Structure

Package-on-package (PoP) structure is widely used in smart phones and tablets in which memory package is directly attached to the top of the application processor. As the market demands more speed and bandwidth, memory devices need more than 1000 I/Os to support future requirements. However← since the package size also becomes smaller and smaller, finer I/O pitch is absolutely required. Although using some new technology can achieve finer I/O pitch, it increases the manufacturing cost. Using traditional mature technology can reduce manufacturing cost, but has limitation in finer I/O pitch. So, it demands a reasonable balance between design, process and cost to develop an applicable PoP structure. In this paper we proposed a novel and cost effective PoP interconnection structure and a multi-layer PoP model. The PoP interconnection was formed by the solder ball on the top package connected to the solder bumps on the bottom package. The solder bump was made of a smaller solder ball attached on a Cu stud bump on the top of bottom substrate. The Cu stud bump was made through wire bonding machines and was coined so that the small solder ball can be attached to it. Using film assist molding technology, a half of the solder ball is exposed outside of molding compound, which can be connected with the solder ball of the top package through reflow process. This PoP interconnection structure was named solder bump through molding (BTM). A three layer PoP vehicle package was designed in our experiments. The top package was a wire bonding BGA, the middle and bottom packages were both flip chip BGA with BTM interconnection structure. The package size of these three packages was 10×10mm2 and ball pitch was 0.4mm. The assembly process of top package was as normal as other wire bonding BGA. The assembly processes of middle and bottom packages were as follows: The Cu stud bumps were first bonded to the top surface of the substrate using wire bonding machines. Small solder balls were attached to the top of Cu stud bumps using stencil tool and then reflowed. After solder bumps were made, all chips were flip bonded to the substrates. Then, using film assist molding and MUF technology, the chips were encapsulated and Cu stud bumps were half exposed. After all the packages were ready, the package stacking and reflow was performed one by one from top to the bottom and the overall three layer PoP was formed. C-scan test and cross section analysis showed that the encapsulation had no voids in most samples. Electrical test results showed the interconnection was good. Reliability study will be also discussed in this paper, which is still in research now. In BTM structure, both Cu stud and solder ball attach can be easily realized. The ball pitch can be 0.4mm or smaller and the process is also applicable for more layer PoP. Thus, BTM PoP structure provides a good solution considering the balance among cost, performance and manufacturing for 3D package. Acknowledgments The authors acknowledge the support of National Science and Technology Major Project (Project number：2013ZX02501003).

Non-Chemical Solder Bump Removal Technique for Repackaging Flip Chip ICs

2012 ◽  
Author(s):  
Mauri Sutton ◽  
George Geoghegan ◽  
Kenneth Schopen ◽  
Kathleen Kingma ◽  
Steve Castro ◽  
...  
Keyword(s):  
Success Rate ◽  
Flip Chip ◽  
Solder Bump ◽  
Wire Bonding ◽  
Solder Bumps ◽  
Bonding Area ◽  
Probe Card ◽  
Bond Pads ◽  
Removal Technique ◽  
Predictable Condition

Abstract In this paper we will discuss an empirically discovered technique to remove residual solder bumps or remnants using reflow and wicking to a gold plated surface rather than mechanical or chemical means. Extraction of flip chip ICs, for the purpose of repackaging, can leave bond pads in inconsistent and undesirable conditions such as 1) retaining remnants of the solder bumps or 2) damaged or eliminated pad metal caused by acid or mechanical means used to separate the IC from the board. These conditions hinder subsequent wire bonding and probe card use. Though other techniques have been found to be suitable at times, the technique described in this paper consistently leaves the bonding area in an acceptable, more predictable condition, as the bulk of the solder bump material is removed. This lends to a higher wire bonding success rate.

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.

scholarly journals Design and Switching Characteristics of Flip-Chip GaN Half-Bridge Modules Integrated with Drivers

2021 ◽  
Vol 11 (15) ◽  
pp. 7057
Author(s):  
Lin Wang ◽  
Zhe Cheng ◽  
Zhi-Guo Yu ◽  
De-Feng Lin ◽  
Zhe Liu ◽  
...  
Keyword(s):  
Flip Chip ◽  
High Electron Mobility Transistors ◽  
Wire Bonding ◽  
High Electron ◽  
Parasitic Inductance ◽  
Switching Performance ◽  
Turn On ◽  
Electron Mobility Transistors ◽  
Chip Technology ◽  
Switching Characteristics

Half-bridge modules with integrated GaN high electron mobility transistors (HEMTs) and driver dies were designed and fabricated in this research. Our design uses flip-chip technology for fabrication, instead of more generally applied wire bonding, to reduce parasitic inductance in both the driver-gate and drain-source loops. Modules were prepared using both methods and the double-pulse test was applied to evaluate and compare their switching characteristics. The gate voltage (Vgs) waveform of the flip-chip module showed no overshoot during the turn-on period, and a small oscillation during the turn-off period. The probabilities of gate damage and false turn-on were greatly reduced. The inductance in the drain-source loop of the module was measured to be 3.4 nH. The rise and fall times of the drain voltage (Vds) were 12.9 and 5.8 ns, respectively, with an overshoot of only 4.8 V during the turn-off period under Vdc = 100 V. These results indicate that the use of flip-chip technology along with the integration of GaN HEMTs with driver dies can effectively reduce the parasitic inductance and improve the switching performance of GaN half-bridge modules compared to wire bonding.

scholarly journals Demonstration of fine pitch FCOB (Flip Chip on Board) assembly based on solder bumps at Fermilab

2009 ◽  
Vol 4 (11) ◽  
pp. T11001-T11001
Author(s):  
E Skup ◽  
M Trimpl ◽  
R Yarema ◽  
J C Yun
Keyword(s):  
Flip Chip ◽  
Fine Pitch ◽  
Solder Bumps

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.

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