Assembly Process Development for Fine Pitch Flip Chip Silicon-to-Silicon 3D Wafer Level Integration with No Flow Underfill

2010 ◽  
Vol 7 (3) ◽  
pp. 146-151 ◽  
Author(s):  
Zhaozhi Li ◽  
Sangil Lee ◽  
Brian J. Lewis ◽  
Paul N. Houston ◽  
Daniel F. Baldwin ◽  
...  
Keyword(s):  
High Performance ◽  
Flip Chip ◽  
Process Development ◽  
Low Cost ◽  
Three Dimensional ◽  
Process Time ◽  
Wafer Level ◽  
Fine Pitch ◽  
3D Packaging ◽  
Small Form Factor

The industry has witnessed the adoption of the flip chip for its low cost, small form factor, high performance, and great I/O flexibility. As three-dimensional (3D) packaging technology moves to the forefront, the flip chip to wafer integration, which is also a silicon-to-silicon assembly, is gaining more and more popularity. No flow underfill is of special interest for the wafer level flip chip assembly, as it can dramatically reduce the process time and the cost per package, due to the reduction in the number of process steps as well as the dispenser and cure oven that would otherwise be necessary for the standard capillary underfill process. This paper introduces the development of a no flow underfill process for a sub-100 micron pitch flip chip to CSP wafer level assembly. Challenges addressed include the no flow underfill reflow profile study, underfill dispense amount study, chip floating control, underfill voiding reduction, and yield improvement. Also, different no flow underfill candidates were investigated to determine the best performing processing material.

No Flow Underfill Process Development for Fine Pitch Flip Chip Silicon to Silicon Wafer Level Integration

2010 ◽  
Vol 2010 (DPC) ◽  
pp. 000708-000735 ◽  
Author(s):  
Zhaozhi Li ◽  
John L. Evans ◽  
Paul N. Houston ◽  
Brian J. Lewis ◽  
Daniel F. Baldwin ◽  
...  
Keyword(s):  
High Performance ◽  
Flip Chip ◽  
Process Development ◽  
Low Cost ◽  
Three Dimensional ◽  
High Yield ◽  
Process Time ◽  
Assembly Process ◽  
Wafer Level ◽  
Fine Pitch

The industry has witnessed the adoption of flip chip for its low cost, small form factor, high performance and great I/O flexibility. As the Three Dimensional (3D) packaging technology moves to the forefront, the flip chip to wafer integration, which is also a silicon to silicon assembly, is gaining more and more popularity. Most flip chip packages require underfill to overcome the CTE mismatch between the die and substrate. Although the flip chip to wafer assembly is a silicon to silicon integration, the underfill is necessary to overcome the Z-axis thermal expansion as well as the mechanical impact stresses that occur during shipping and handling. No flow underfill is of special interest for the wafer level flip chip assembly as it can dramatically reduce the process time as well as bring down the average package cost since there is a reduction in the number of process steps and the dispenser and cure oven that would be necessary for the standard capillary underfill process. Chip floating and underfill outgassing are the most problematic issues that are associated with no flow underfill applications. The chip floating is normally associated with the size/thickness of the die and volume of the underfill dispensed. The outgassing of the no flow underfill is often induced by the reflow profile used to form the solder joint. In this paper, both issues will be addressed. A very thin, fine pitch flip chip and 2x2 Wafer Level CSP tiles are used to mimic the assembly process at the wafer level. A chip floating model will be developed in this application to understand the chip floating mechanism and define the optimal no flow underfill volume needed for the process. Different reflow profiles will be studied to reduce the underfill voiding as well as improve the processing yield. The no flow assembly process developed in this paper will help the industry understand better the chip floating and voiding issues regarding the no flow underfill applications. A stable, high yield, fine pitch flip chip no flow underfill assembly process that will be developed will be a very promising wafer level assembly technique in terms of reducing the assembly cost and improving the throughput.

Wafer Level Assembly Technique Development for Fine Pitch Flip Chip 3D Die-to-Wafer Integration

2010 ◽  
Vol 2010 (1) ◽  
pp. 000548-000553
Author(s):  
Zhaozhi Li ◽  
Brian J. Lewis ◽  
Paul N. Houston ◽  
Daniel F. Baldwin ◽  
Eugene A. Stout ◽  
...  
Keyword(s):  
Flip Chip ◽  
Low Cost ◽  
Three Dimensional ◽  
Cost Effective ◽  
Market Demand ◽  
Wafer Level ◽  
Packaging Technology ◽  
Fine Pitch ◽  
3D Packaging ◽  
Assembly Technique

Three Dimensional (3D) Packaging has become an industry obsession as the market demand continues to grow toward higher packaging densities and smaller form factor. In the meanwhile, the 3D die-to-wafer (D2W) packaging structure is gaining popularity due to its high manufacturing throughput and low cost per package. In this paper, the development of the assembly process for a 3D die-to-wafer packaging technology, that leverages the wafer level assembly technique and flip chip process, is introduced. Research efforts were focused on the high-density flip chip wafer level assembly techniques, as well as the challenges, innovations and solutions associated with this type of 3D packaging technology. Processing challenges and innovations addressed include flip chip fluxing methods for very fine-pitch and small bump sizes; wafer level flip chip assembly program creation and yield improvements; and set up of the Pb-free reflow profile for the assembled wafer. 100% yield was achieved on the test vehicle wafer that has totally 1,876 flip chip dies assembled on it. This work has demonstrated that the flip chip 3D die-to-wafer packaging architecture can be processed with robust yield and high manufacturing throughput, and thus to be a cost effective, rapid time to market alternative to emerging 3D wafer level integration methodologies.

Pre-Applied Underfill (PAUF) for Fine Pitch Flip Chip 3D Chip Stacking

2012 ◽  
Vol 2012 (DPC) ◽  
pp. 001432-001451
Author(s):  
Anupam Choubey ◽  
E. Anzures ◽  
A. Dhoble ◽  
D. Fleming ◽  
M. Gallagher ◽  
...  
Keyword(s):  
High Performance ◽  
Flip Chip ◽  
Fatigue Testing ◽  
Electrical Performance ◽  
Process Time ◽  
Wafer Level ◽  
Fine Pitch ◽  
Semiconductor Packages ◽  
Reliability Performance ◽  
3D Chip Stacking

Current demands of the industry on performance and cost has triggered the electronics industry to use high I/O counts semiconductor packages. Copper pillar technology has been widely adopted for introducing high I/O counts in Flip Chip and 3D Chip Stacking. With the introduction of flipchip technology new avenues have been generated involving 3D chip stacking to expand the need for high performance. With the increase in the demand for high density, copper pillar technology is being adopted in the industry to address the fine pitch requirements in addition to providing enhanced thermal and electrical performance. For this study, Copper pillars and SnAg were electrolytically deposited using Dow's electroplating chemistry on internally developed test structures. After plating, wafers were diced and bonded using thermocompression bonding techniques. Copper pillar technology has been enabled to pass reliability requirements by using Underfill materials during the bonding. Underfill materials assist in redistributing the stress generated during reliability such as thermal fatigue testing. Out of the several Underfill technologies available, we have focused on pre-applied or wafer level underfill materials with 60% silica filler for this study. In the pre-applied underfill process the underfill is applied prior to bonding by coating directly on the whole wafer. Pre-applied underfill reduces the underfill dispense process time by being present prior to bonding. In this study, we have demonstrated the application of wafer level underfill for fine pitch bonding of internally developed test vehicles with SnAg-capped copper pillars with 25 μm diameter and 50 μm bump pitch. This paper demonstrates bonding alignment for fine pitch assembly with wafer level underfill to achieve 100% good solder joins after bonding. Wafer level underfill has been demonstrated successfully to bond and pass JEDEC level 3 preconditioning and standard TCT, HTS and HAST reliability tests. This paper also discusses defect mechanisms which have been found to optimize the bonding process and reliability performance. Alan/Rey ok move from Flip Chip and Wafer Level Packaging 1-6-12.

FOWLP Technology as an Wafer Level System in Packaging (SiP) Solution

2017 ◽  
Vol 2017 (DPC) ◽  
pp. 1-41 ◽  
Author(s):  
Lewis(In Soo) Kang
Keyword(s):  
High Performance ◽  
Flip Chip ◽  
Low Cost ◽  
Industrial Applications ◽  
System Control ◽  
Wafer Level ◽  
Communication Module ◽  
3D Packaging ◽  
Control Application ◽  
Wafer Level Package

The market of Connectivity, Internet of Things (IoT), Wearable and Smart industrial applications leads Fan Out Wafer Level Package (FOWLP) technologies to a promising solution to overcome the limitation of conventional wafer level package, flip chip package and wire bonding package in terms of the solution of low cost, high performance and smaller form factor packaging. Moreover, FOWLP technology can be extended to system-in-package (SiP) area, such as multi chip 2D package and 3D stack package types. nepes Corporation has developed several advanced package platforms such as single, multi dies and 2D, 3D packaging by using FOWLP and embedding technologies. To fulfill SiP (system-in-package) with FOWLP, several dies and components have been embedded into one package which offers 40~90 % of volumetric shrink compared to the current module system with the flexibility of product design for end users. 3D package technology of PoP (Package on Package) structure will be introduced for communication module and system control application.

Flip-chip Packages with Periphery Cu Pillar Bumps as Wire Bond Replacement—Design, Modeling & Characterization

2013 ◽  
Vol 2013 (1) ◽  
pp. 000235-000235
Author(s):  
Zhe Li ◽  
Siow Chek Tan ◽  
Yee Huan Yew ◽  
Pheak Ti Teh ◽  
MJ Lee ◽  
...  
Keyword(s):  
High Speed ◽  
High Performance ◽  
Flip Chip ◽  
Low Cost ◽  
Electrical Performance ◽  
Package Design ◽  
Cu Pillar ◽  
Fine Pitch ◽  
Field Programmable ◽  
Small Form Factor

Cu pillar is an emerging interconnect technology which offers many advantages compared to traditional packaging technologies. This paper presents a novel packaging solution with periphery fine pitch Cu pillar bumps for low cost and high performance Field Programmable Gate Array (FPGA) devices. Wire bonding has traditionally been the choice for low cost implementation of memory interfaces and high speed transceivers. Migration to Cu pillar technology is mainly driven by increasing demand for IO density and package small form factor. Cu pillar bumps also offer significant improvement on electrical performance compared to wire bonds. This paper presents Cu pillar implementation in an 11×11mm flip chip CSP package. Package design is optimized for serial data transport up to 6.114Gbps to meet CPRI_LVII and PCIe Gen2 compliance requirements. Package design strategy includes die and package co-design, SI/PI modeling and physical layout optimization.

SiP(System in Package) Solutions with Wafer Level Packaging Technology

2011 ◽  
Vol 2011 (DPC) ◽  
pp. 002226-002253 ◽  
Author(s):  
In Soo Kang ◽  
Jong Heon (Jay) Kim
Keyword(s):  
Embedded System ◽  
High Performance ◽  
Low Cost ◽  
Wafer Level ◽  
Molding Compound ◽  
Wafer Level Packaging ◽  
Ic Packaging ◽  
Chip Size ◽  
Bonding Technology ◽  
Small Form Factor

In mobile application, the WLP technology has been developing to make whole package size almost same as chip size. However, the I/O per chip unit area has increased so that it gets difficult to realize ideal pad pitch for better reliability. Recently, to achieve the thin and small size, high performance and low cost semiconductor package, Embedding Die and Fanout Technologies have been suggested and developed based on wafer level processing. In this work, as a solution of system in package, wafer level embedded package and fanout technology will be reviewed. Firstly, Wafer level embedded System in Package (WL-eSiP) which has daughter chip (small chip) embedded inside mother chip (bigger chip) without any special substrate has been suggested and developed. To realize wafer level embedded system in package (WL-eSiP), wafer level based new processes like wafer level molding for underfilling and encapsulation by molding compound without any special substrate have been applied and developed, including high aspect ratio Cu bumping, mold thinning and chip-to-wafer flipchip bonding. Secondly, Fan-out Package is considered as alternative package structure which means merged package structure of WLCSP (wafer level chip size package) and PCB process. We can make IC packaging widen area for SIP(System in Package) or 3D package. In addition, TSV and IPD are key enabling technology to meet market demands because TSV interconnection can provide wider bandwidth and high transmission speed due to vertical one compared to wire bonding technology and IPD can provide higher performance, more area saving to be assembled and small form factor compared to discrete passive components.

Ultra Fine Pitch RDL Development in Multi-layer eWLB (embedded Wafer Level BGA) Packages

2015 ◽  
Vol 2015 (1) ◽  
pp. 000822-000826 ◽  
Author(s):  
Won Kyoung Choi ◽  
Duk Ju Na ◽  
Kyaw Oo Aung ◽  
Andy Yong ◽  
Jaesik Lee ◽  
...  
Keyword(s):  
High Performance ◽  
Process Development ◽  
Cost Effective ◽  
Access Point ◽  
Data Access ◽  
Memory Device ◽  
Logic Device ◽  
Wafer Level ◽  
Component Level ◽  
Fine Pitch

The market for portable and mobile data access devices connected to a virtual cloud access point is exploding and driving increased functional convergence as well as increased packaging complexity and sophistication. This is creating unprecedented demand for higher input/output (I/O) density, higher bandwidths and low power consumption in smaller package sizes. There are exciting interconnect technologies in wafer level packaging such as eWLB (embedded Wafer Level Ball Grid Array), 2.5D interposers, thin PoP (Package-on-Package) and TSV (Through Silicon Via) interposer solutions to meet these needs. eWLB technologies with the ability to extend the package size beyond the area of the chip are leading the way to the next level of high density, thin packaging capability. eWLB provides a robust packaging platform supporting very dense interconnection and routing of multiple die in very reliable, low profile, low warpage 2.5D and 3D solutions. The use of these embedded eWLB packages in a side-by-side configuration to replace a stacked package configuration is critical to enable a more cost effective mobile market capability. Combining the analog or memory device with digital logic device in a semiconductor package can provide an optimum solution for achieving the best performance in thin, multiple-die integration aimed at very high performance. This paper highlights the rapidly moving trend towards eWLB packaging technologies with ultra fine 2/2μm line width and line spacing and multi-layer RDL. A package design study, process development and optimization, and mechanical characterization will be discussed as well as test vehicle preparation. JEDEC component level reliability test results will also be presented.

Ultra Fine Pitch RDL Development in Multi-layer eWLB (embedded Wafer Level BGA) Packages

2016 ◽  
Vol 2016 (DPC) ◽  
pp. 000809-000825
Author(s):  
Bernard Adams ◽  
Won Kyung Choi ◽  
Duk Ju Na ◽  
Andy Yong ◽  
Seung Wook Yoon ◽  
...  
Keyword(s):  
Line Width ◽  
High Performance ◽  
Process Development ◽  
Data Access ◽  
Electrical Performance ◽  
Logic Device ◽  
Wafer Level ◽  
Component Level ◽  
Wafer Level Packaging ◽  
Fine Pitch

The market for portable and mobile data access devices connected to a virtual cloud access point is exploding and driving increased functional convergence as well as increased packaging complexity and sophistication. This is creating unprecedented demand for higher input/output (I/O) density, higher bandwidths and low power consumption in smaller package sizes. There are exciting interconnect technologies in wafer level packaging such as eWLB (embedded Wafer Level Ball Grid Array), 2.5D interposers, thin PoP (Package-on-Package) and TSV (Through Silicon Via) interposer solutions to meet these needs. eWLB technologies with the ability to extend the package size beyond the area of the chip are leading the way to the next level of high density, thin packaging capability. eWLB provides a robust packaging platform supporting very dense interconnection and routing of multiple die in very reliable, low profile, low warpage 2.5D and 3D solutions. The use of these embedded eWLB packages in a side-by-side configuration to replace a stacked package configuration is critical to enable a more cost effective mobile market capability. Combining the analog or memory device with digital logic device in a semiconductor package can provide an optimum solution for achieving the best performance in thin, multiple-die integration aimed at very high performance. One of the greatest challenges facing wafer level packaging at present is the availability of routing and interconnecting high I/O fine pitch area array. RDL (redistribution layer) allows signal and supply I/O's to be redistributed to a footprint larger than the chip footprint in eWLB . Required line widths and spacing of 2/2 μm for eWLB applications support the bump pitch of less than 40um. Finer line width and spacing are critical for further design flexibility as well as electrical performance improvement. This paper highlights the rapidly moving trend towards eWLB packaging technologies with ultra fine 2/2um line width and line spacing and multi-layer RDL. A package design study, process development and optimization, and mechanical characterization will be discussed as well as test vehicle preparation. JEDEC component level reliability test results will also be presented.

Advances in the Fabrication Processes and Applications of Wafer Level Packaging

2014 ◽  
Vol 136 (2) ◽  
Author(s):  
Peisheng Liu ◽  
Jinlan Wang ◽  
Liangyu Tong ◽  
Yujuan Tao
Keyword(s):  
Integrated Circuit ◽  
Microelectromechanical Systems ◽  
Low Cost ◽  
Electrical Performance ◽  
Wafer Level ◽  
Wafer Level Packaging ◽  
3D Packaging ◽  
Circuit Fabrication ◽  
Fast Development ◽  
Small Form Factor

Fast development of wafer level packaging (WLP) in recent years is mainly owing to the advances in integrated circuit fabrication process and the market demands for devices with high electrical performance, small form factor, low cost etc. This paper reviews the advances of WLP technology in recent years. An overall introduction to WLP is presented in the first part. The fabrication processes of WLP and redistribution technology are introduced in the second part. Reliability problems of WLPs, such as the strength of solder joints and reliability problems concerning fan-out WLPs are introduced in the third part. Typical applications of WLP technologies are discussed in the last part, which include the application of fan-out WLP, 3D packaging integrating with WLP technologies and its application in microelectromechanical systems (MEMS).

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