Evalulation of Electrodeposited Photoresists for use in the Fabrication of an Optochip Silicon Interposer

2011 ◽  
Vol 2011 (DPC) ◽  
pp. 001555-001595
Author(s):  
Cornelia Tsang ◽  
Janet Okada ◽  
Eric Huenger
Keyword(s):  
Printed Circuit Boards ◽  
Process Integration ◽  
Product Yield ◽  
Wafer Surface ◽  
Wafer Level ◽  
Design Elements ◽  
Conformal Coating ◽  
3D Packaging ◽  
Study Process ◽  
Negative Tone

As 3D packaging technology and designs evolve, increasing complexity has been introduced in the fabrication of these devices. The integration of optical devices along with electronic wired elements such as the package platform identified in image sensors is one prime example where the design elements of the structures significantly increase the topography on the surface of the system. This multiplies the degree of difficulty in the lithography solution chosen to facilitate fabrication of these structures. The use of electrodeposited (ED) photoresists is a technology platform that has been used in MEMs, printed circuit boards, backside vias, etc, and can play a significant role in enabling new 3D packaging solutions. In this research, the successful fabrication of an Optochip silicon interposer, which integrates electrical and optical components onto a single substrate with high density interconnection, was enabled through use of electrodeposited (ED) photoresist. The Optochip interposer was manufactured in a standard 200 mm semiconductor fab and this precipitated the process integration requirement of first etching “optical vias” into the silicon at wafer-level prior to the final lithography steps. As such, challenging topography was introduced into the system. A resist solution able to address the following conditions was required: 1) sufficient conformal coating into large optical vias measuring 150 um diameter by 200 um depth, 2) no resist pull-back over sharp 90 degree angle corners where the optical vias met the wafer surface, 3) ability to resolve 30 um diameter surface pads at 50 um pitch and 4) chemical resistance to Ni and cyanide-based Au plating baths. This presentation will discuss how various photoresists were examined that resulted in ED photoresist being chosen for the aforementioned application. Both negative-tone and positive-tone ED photoresists were considered. Experiments to study process parameters and environmental factors on product yield were performed using test wafers with optical vias. These experiments resulted in positive-tone ED photoresist being selected. Test wafers plated with NiAu resulted in ~ 90% process yield. The presentation will conclude by demonstrating the ability to achieve good yield on integrated product wafers.

3D Process Integration – Requirements and Challenges

2008 ◽  
Vol 1112 ◽  
Author(s):  
Juergen Max Wolf ◽  
Armin Klumpp ◽  
Kai Zoschke ◽  
Robert Wieland ◽  
Lars Nebrich ◽  
...  
Keyword(s):  
System Integration ◽  
New Technologies ◽  
Process Integration ◽  
High Volume ◽  
System Level ◽  
Wafer Level ◽  
System Architectures ◽  
Future System ◽  
3D Packaging ◽  
Third Dimension

AbstractHeterogeneous system integration is one of the key topics for future system integration. Scaling of System on Chip (SoC) alone does not address today's requirements of smart electronic systems in terms of performance, functionality, miniaturization, low production cost and time to market. The traditional microelectronic packaging will more and more convert into complex sys-tem integration. ‘More than Moore’ will be required due to tighter integration of system level components at the package level. This trend leads to advanced System in Package solutions (SiP) which require the synergy and a combination of wafer level and board integration technologies and which are rapidly evolving from a specialty technology used in a narrow set of applications to a high volume technology with wide ranging impact on electronics markets especially due to the high volume and very cost competitive consumer and communication market. Advanced SiP approaches explore the third dimension which results in complex system architectures that also require, beside new technologies and improved materials, adequate system design tools and reli-ability models. One of the most promising technology approaches is 3D packaging which in-volves a set of different integration approaches including stacked packages, silicon interposer with Through Silicon Vias (TSV) and embedding technologies. The paper highlights future sys-tem and potential technical solutions.

Characterization of Unfilled Tungsten Plugs on a 0.35μm CMOS Multilevel Metallization Process

1996 ◽  
Author(s):  
H. Sur ◽  
S. Bothra ◽  
Y. Strunk ◽  
J. Hahn
Keyword(s):  
Process Development ◽  
Process Integration ◽  
Wafer Level ◽  
Electrical Failure ◽  
Analysis Techniques ◽  
Integration Approach ◽  
Intermetal Dielectric ◽  
Metallization Process ◽  
Section Analysis

Abstract An investigation into metallization/interconnect failures during the process development phase of an advanced 0.35μm CMOS ASIC process is presented. The corresponding electrical failure signature was electrical shorting on SRAM test arrays and subsequently functional/Iddq failures on product-like test vehicles. Advanced wafer-level failure analysis techniques and equipment were used to isolate and identify the leakage source as shorting of metal lines due to tungsten (W) residue which was originating from unfilled vias. Further cross-section analysis revealed that the failing vias were all exposed to the intermetal dielectric spin-on glass (SOG) material used for filling the narrow spaces between metal lines. The outgassing of the SOG in the exposed regions of the via prior to and during the tungsten plug deposition is believed to be the cause of the unfilled vias. This analysis facilitated further process development in eliminating the failure mechanism and since then no failures of this nature have been observed. The process integration approach used to eliminate the failure is discussed.

Innovative 3D Structures Utilizing Wafer Level Fan-Out (WLFO) Technology

2013 ◽  
Vol 2013 (DPC) ◽  
pp. 001486-001519
Author(s):  
Curtis Zwenger ◽  
JinYoung Khim ◽  
YoonJoo Khim ◽  
SeWoong Cha ◽  
SeungJae Lee ◽  
...  
Keyword(s):  
Low Cost ◽  
Ease Of Use ◽  
Wafer Level ◽  
3D Structures ◽  
Wafer Level Packaging ◽  
Functional Convergence ◽  
3D Packaging ◽  
Improved Design ◽  
On Chip ◽  
Mobile Handset

The tremendous growth in the mobile handset, tablet, and networking markets has been fueled by consumer demand for increased mobility, functionality, and ease of use. This, in turn, has been driving an increase in functional convergence and 3D integration of IC devices, resulting in the need for more complex and sophisticated packaging techniques. A variety of advanced IC interconnect technologies are addressing this growing need, such as Thru Silicon Via (TSV), Chip-on Chip (CoC), and Package-on-Package (PoP). In particular, the emerging Wafer Level Fan-Out (WLFO) technology provides unique and innovative extensions into the 3D packaging realm. Wafer Level Fan-Out is a package technology designed to provide increased I/O density within a reduced footprint and profile for low density single & multi-die applications at a lower cost. The improved design capability of WLFO is due, in part, to the fine feature capabilities associated with wafer level packaging. This can allow much more aggressive design rules to be applied compared to competing laminate-based technologies. In addition, the unique characteristics of WLFO enable innovative 3D structures to be created that address the need for IC integration in emerging mobile and networking applications. This paper will review the development of WLFO and its extension into unique 3D structures. In addition, the advantages of these WLFO designs will be reviewed in comparison to current competing packaging technologies. Process & material characterization, design simulation, and reliability data will be presented to show how WLFO is poised to provide robust, reliable, and low cost 3D packaging solutions for advanced mobile and networking products.

Journey Toward Process Convergence in TSV Technology

2010 ◽  
Vol 2010 (DPC) ◽  
pp. 001282-001321
Author(s):  
Sesh Ramaswami ◽  
John Dukovic
Keyword(s):  
Process Integration ◽  
Semiconductor Industry ◽  
Rapid Development ◽  
Chemical Mechanical Planarization ◽  
Cost Effective ◽  
Superior Performance ◽  
Wafer Level ◽  
Unit Process ◽  
Integration Schemes ◽  
Process Convergence

Continuous demand for more advanced electronic devices with higher functionality and superior performance in smaller packages is driving the semiconductor industry to develop new and more advanced 3D wafer-level interconnect technologies involving TSVs (through-silicon vias). The TSVs are created either on full-thickness wafer from the wafer front-side ¡V as part of wafer-fab processing during Middle-Of-Line (¡§via middle¡¨) or Back-End-Of-Line (¡§via last BEOL¡¨) ¡V or from the wafer backside after wafer thinning (¡§via last backside¡¨). Independent of the specific approach, the main steps include via etching, lining with insulator, copper barrier/seed deposition, via fill, and chemical mechanical planarization (CMP). Over the past year, the industry has been converging toward some primary unit processes and integration schemes for creating the TSVs. A common cost-of-ownership framework has also begun to emerge. Active collaboration underway among equipment suppliers, materials providers and end users is bringing about rapid development and validation of cost-effective TSV technology in end products. This presentation will address unit-process and integration challenges of TSV fabrication in the context of 20x100ƒÝm and 5x50ƒÝm baseline process flows at Applied Materials. Highlights of wafer-backside process integration involving wafers bonded to silicon or glass carriers will also be discussed.

Cost Effective and High Performance 28nm FPGA with New Disruptive Silicon-Less Interconnect Technology (SLIT)

2014 ◽  
Vol 2014 (1) ◽  
pp. 000599-000605 ◽  
Author(s):  
Woon-Seong Kwon ◽  
Suresh Ramalingam ◽  
Xin Wu ◽  
Liam Madden ◽  
C. Y. Huang ◽  
...  
Keyword(s):  
High Performance ◽  
Process Integration ◽  
Cost Effective ◽  
Disruptive Innovation ◽  
Design Rule ◽  
Wind Condition ◽  
Silicon Etching ◽  
Wafer Level ◽  
Effective Manner ◽  
Interconnect Technology

This paper introduces the first comprehensive demonstration of new disruptive innovation technology comprising multiple Xilinx patent-pending innovations for highly cost effective and high performance Xilinx FPGA, which is so called stack silicon-less interconnect technology (SLIT) that provides the equivalent high-bandwidth connectivity and routing design-rule as stack silicon interconnect (SSI) technology at a cost-effective manner. We have successfully demonstrated the overall process integration and functions of our new SLIT-employed package using Virtex® -7 2000T FPGA product. Chip-to-Wafer stacking, wafer level flux cleaning, micro-bump underfilling, mold encapsulation are newly developed. Of all technology elements, both full silicon etching with high etch selectivity to dielectric/fast etch rate and wafer warpage management after full silicon etching are most crucial elements to realize the SLIT technology. In order to manage the wafer warpage after full Si removal, a couple of knobs are identified and employed such as top reinforcement layer, micro-bump underfill properties tuning, die thickness/die-to-die space/total thickness adjustments. It's also discussed in the paper how the wafer warpage behaves and how the wafer warpge is managed. New SLIT module shows excellent warpage characteristics of only −30 μm ~ −40 μm at room temperature for 25 mm × 31 mm in size and +20 μm ~ +25 μm at reflow temperature. Thermal simulation results shows that thermal resistance of new SLIT package is almost comparable to that of standard 2000T FCBGA package using TSV interposer with standard heat sink configuration and air wind condition. The reliability assessment is now under the study.

Solder Joint Reliability Study for Wafer Level Packages on Flexible and Rigid Boards

2013 ◽  
Vol 2013 (1) ◽  
pp. 000039-000044
Author(s):  
Gary Gu ◽  
Jon Chadwick ◽  
Daniel Jin
Keyword(s):  
Solder Joint ◽  
Parametric Design ◽  
Low Cost ◽  
Wafer Level ◽  
Solder Joint Reliability ◽  
Conformal Coating ◽  
Joint Reliability ◽  
Chip Size ◽  
The Right ◽  
Elastic Plastic Materials

Applications of Wafer Level Packages (WLPs) have shown tremendous growth in the rapid developing smartphones and other portable electronic devices. The technology trends lead to smaller chip size, low cost, and more integrated functions, but also face higher reliability requirements due to the reduced number of solder bumps as well as smaller bump size and height. New assembly technologies such as flexible phone board and conformal coating also brought up new thermo-mechanical reliability challenges. Based on 3D finite element modeling, the current studies focus on solder joint reliability of WLPs and compared between flex based and traditional rigid based WLP assemblies. Conformal coated and underfilled WLPs as well as some bump parameters are also studied. The parametric studies were carried out in ANSYS and all models were created by using APDL (ANSYS Parametric Design Language) scripts. Each simulation starts from stress free status set at solder reflow temperature and were subjected to thermal cyclic load between −40 and +125°C with ramp and dwell time. Creep strain was considered for solder alloys and kinematic plastic hardening was considered for other elastic-plastic materials. The solder fatigue life is estimated by using modified Coffin-Manson equation and was compared with available thermal cycling test data. The results show that underfill is still the most effective option and conformal coating can play an important role if the right material is selected. Bump parameters such as height, which have certain effects on the solder reliability on WLP-on-Rigid, have limited impact on WLP-on-Flex assembly.

Reliability Study of Reference Semiconductor Encapsulation Materials for Biocompatible Packaging

2012 ◽  
Vol 2012 (1) ◽  
pp. 000148-000153
Author(s):  
Karl Malachowski ◽  
Karen Qian ◽  
Maaike Op de Beeck ◽  
Rita Verbeeck ◽  
George Bryce ◽  
...  
Keyword(s):  
Elevated Temperatures ◽  
Process Integration ◽  
Material Selection ◽  
Semiconductor Industry ◽  
Electrical Performance ◽  
Integration Scheme ◽  
Back Side ◽  
Wafer Level ◽  
Nitride Layers

Material selection is the key issue when developing a biocompatible packaging process for implantable electronic systems. To secure a reliable performance of the chip in such a package, its encapsulation has to be considered up-front in the wafer-level integration scheme. A differentiation of two main material types can be made:1) Insulating or passive materials functioning as a bi-directional diffusion barrier preventing body fluids leaking into the package causing systems malfunction due to possible materials corrosion and also avoiding a leakage of built-in materials to the in-vivo environment and2) Conductive or active materials as diffusion barriers, e.g. against copper diffusion or as direct external contacts responsible for electrical performance of the system. This study investigates the properties of two widely used insulating materials in the semiconductor industry, the nitride and the oxide. Both material types are deposited in a PECVD system using different temperatures; 400 ° C for CMOS compatibility and 200 ° C for wafer back side process integration when a temporary carrier system is used. The biocompatibility investigations of these materials (evaluated using cell lines and primary cells) show promising results. However, for the long term application, the stability results for the oxide layers show hydration effects resulting in material degradation where the nitride layers clearly show corrosion and are even etched when elevated temperatures are applied. This fact is surprising since nitride layers are widely used as a humidity barrier for various chip types but obviously not suitable for a direct contact with liquids. Various analysis methods using e.g. Fourier Transformed IR Spectroscopy or mass measurements substantiate this thesis.

New Stacked Die Interconnect Technology for High-Performance and Low-Cost FPGA

2015 ◽  
Vol 12 (3) ◽  
pp. 111-117
Author(s):  
Woon-Seong Kwon ◽  
Suresh Ramalingam ◽  
Xin Wu ◽  
Liam Madden ◽  
C. Y. Huang ◽  
...  
Keyword(s):  
High Performance ◽  
Flip Chip ◽  
Process Integration ◽  
Cost Effective ◽  
Design Rule ◽  
Innovative Technology ◽  
Wind Condition ◽  
Wafer Level ◽  
Effective Manner ◽  
Interconnect Technology

This article introduces the first comprehensive demonstration of new innovative technology comprising multiple key technologies for highly cost-effective and high-performance Xilinx field programmable gate array (FPGA), which is so-called stack silicon-less interconnect technology (SLIT) that provides the equivalent high-bandwidth connectivity and routing design-rule as stack silicon interconnect (SSI) technology at a cost-effective manner. We have successfully demonstrated the overall process integration and functions of our new SLIT-employed package using Virtex®-7 2000T FPGA product with chip-to-wafer stacking, wafer-level flux cleaning, microbump underfilling, mold encapsulation, and backside silicon removal. Of all technology elements, both full silicon removal process with faster etching and no dielectric layer damage and wafer warpage management after full silicon etching are most crucial elements to realize the SLIT technology. To manage the wafer warpage after full Si removal, a couple of knobs are identified and used such as top reinforcement layer, microbump underfill properties tuning, die thickness, die-to-die space, and total thickness adjustments. It is also discussed in the article how the wafer warpage behaves and how the wafer warpage is managed. New SLIT module shows excellent warpage characteristics of only −30 μm ∼ −40 μm at room temperature (25°C) for 25 mm × 31 mm in size and +20 μm ∼ +25 μm at reflow temperature (250°C). Thermal simulation results shows that thermal resistance of new SLIT package is almost comparable to that of standard 2000T flip-chip ball grid array (FC-BGA) package using through silicon via interposer with standard heat sink configuration and air wind condition. The reliability assessment is now under the study.

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