Strong, high-yield and low-temperature thermocompression silicon wafer-level bonding with gold

2004 ◽  
Vol 14 (7) ◽  
pp. 884-890 ◽  
Author(s):  
M M V Taklo ◽  
P Storås ◽  
K Schjølberg-Henriksen ◽  
H K Hasting ◽  
H Jakobsen
Keyword(s):  
Low Temperature ◽  
Silicon Wafer ◽  
High Yield ◽  
Wafer Level

Low-temperature Cu-Cu thermocompression bonding for encapsulation of a MEMS mirror

2019 ◽  
Vol 2019 (NOR) ◽  
pp. 000012-000016
Author(s):  
Henri Ailas ◽  
Jaakko Saarilahti ◽  
Tuomas Pensala ◽  
Jyrki Kiihamäki
Keyword(s):  
Low Temperature ◽  
Bond Strength ◽  
Bonding Temperature ◽  
Bonding Process ◽  
Ex Situ ◽  
High Yield ◽  
Maximum Temperature ◽  
Wafer Level ◽  
Cu Films ◽  
Thermocompression Bonding

Abstract In this study, a low temperature wafer-level packaging process aimed for encapsulating MEMS mirrors was developed. The glass cap wafer used in the package has an antireflective (AR) coating that limits the maximum temperature of the bonding process to 250°C. Copper thermocompression was used as copper has a high self-diffusivity and the native oxidation on copper surfaces can be completely removed with combination of ex situ acetic acid wet-etch and in situ forming gas anneal. Making it suitable for a development of a low temperature bonding process. In this work, bonding on of sputtered and electrodeposited copper films was studied on temperatures ranging from 200°C to 300°C as well as the effect of pretreatment on bond strength. The study presents a successful thermocompression bonding process for sputtered Cu films at a low temperature of 200°C with high yield of 97 % after dicing. The bond strength was recorded to be 75 MPa, well above the MIL-STD-883E standard (METHOD 2019.5) rejection limit of 6.08 MPa. The high dicing yield and bond strength suggest that the thermocompression bonding could be possible even at temperatures below 200°C. However, the minimum bonding temperature was not yet determined in this study.

Commercial-off-the-Shelf (COTS) 3D Integration using Low Temperature Wafer Bonding

2011 ◽  
Vol 2011 (DPC) ◽  
pp. 000836-000858 ◽  
Author(s):  
Sang Hwui Lee ◽  
Michael Khbeis
Keyword(s):  
Low Temperature ◽  
Wafer Bonding ◽  
High Yield ◽  
Activation Process ◽  
Wafer Level ◽  
3D Integration ◽  
Release Process ◽  
Adhesive Film ◽  
Die Set ◽  
Commercial Off The Shelf

This paper reports on a successful 3D integration (3DI) of multi-purpose signal processor (MSP) chips with memory chips using die-to-wafer (D2W) and wafer-to-wafer (W2W) bonding technologies. 3D integration enables compact systems of commercial-off-the-shelf (COTS) parts with high functionality using a wafer-level process for better thinning process uniformity and high yield throughput. The3D system is comprised of commercial Flash memory bare die and MSP bare die. The bare die are face-down aligned to a 150mm diameter silicon handle wafer with alignment marks polished silicon surface. Unique features on the commercial die are detected and used for die registration using a flip-chip bonder with vision automation. An adhesive film between the die and silicon handle wafer are used for temporary bonding. After the die-to-wafer population and bonding, the die substrates are thinned at the wafer-level to a target of 60 microns for the memory die and 25 microns for the MSP die, respectively. The thinned memory die set is permanently transferred onto a 150mm diameter silicon carrier wafer using a low temperature silicon covalent wafer bonding. Following bonding, an adhesive film release process is used to separate the memory die set from the temporary handle wafer. The thinned MSP die on a second handle wafer are then aligned to the thinned memory die set using a wafer-to-wafer alignment tool, and bonded with thin-film polyimide in a high-yield, low temperature wafer bonding process, followed by the release process to separate the MSP die set from the handle wafer. Finally, the MSP/memory stack are electrically connected using a via-last through-silicon-via (TSV) process. One of the key considerations for COTS 3DI is to meet the back-end-of-line (BEOL) thermal budgets of 350–400 Celsius. Plasma-assisted preparation facilitates the reduction in thermal budget for silicon covalent bonding and is performed at 150 Celsius, followed by a long-term annealing process at 175 Celsius. Stacking of thinned die relies on low temperature polyimide bonding that is performed at 200 Celsius. Fluorine and oxygen based plasma surface activation process and CTE-matched polyimide bonding play a critical role in enabling the low temperature bonding for this 3D MSP/memory integration. The thinning and bonding processing details that are presented in this paper are essential for COTS 3DI but can also be applied to several low-profile multi-chip module and packaging applications.

Low Temperature Al-Al Thermo-compression Bonding with Sn Oxidation Protect Layer for Wafer-level Hermetic Sealing

2016 ◽  
Vol 136 (6) ◽  
pp. 237-243 ◽  
Author(s):  
Shiro Satoh ◽  
Hideyuki Fukushi ◽  
Masayoshi Esashi ◽  
Shuji Tanaka
Keyword(s):  
Low Temperature ◽  
Wafer Level ◽  
Hermetic Sealing

High Precision Low Temperature Direct Wafer Bonding Technology for Wafer-Level 3D ICs Manufacturing

2016 ◽  
Vol 75 (9) ◽  
pp. 345-353 ◽  
Author(s):  
F. Kurz ◽  
T. Plach ◽  
J. Suss ◽  
T. Wagenleitner ◽  
D. Zinner ◽  
...  
Keyword(s):  
Low Temperature ◽  
High Precision ◽  
Wafer Bonding ◽  
Wafer Level ◽  
3D Ics ◽  
Direct Wafer Bonding ◽  
Bonding Technology

Low Temperature Direct Silicon Wafer Bonding Using Argon Activation

1997 ◽  
Vol 36 (Part 2, No. 5A) ◽  
pp. L527-L528 ◽  
Author(s):  
Robert W. Bower ◽  
Frank Y.-J. Chin
Keyword(s):  
Low Temperature ◽  
Silicon Wafer ◽  
Wafer Bonding

Development of High Density RDL Technologies for Panel Level Processing

2019 ◽  
Vol 2019 (DPC) ◽  
pp. 000284-000313
Author(s):  
Lars Böttcher ◽  
S. Karaszkiewicz ◽  
F. Schein ◽  
R. Kahle ◽  
A. Ostmann
Keyword(s):  
Coefficient Of Thermal Expansion ◽  
High Density ◽  
Organic Films ◽  
High Yield ◽  
Wafer Level ◽  
Final Size ◽  
Process Yield ◽  
Cu Pillar ◽  
Thin Organic Films ◽  
Advanced Packaging

Advanced packaging technologies like wafer-level fan-out and 3D System-in-Packages (SIPs) are rapidly penetrating the market of electronic components. A recent trend to reduce cost is the extension of processes to large manufacturing formats, called Panel Level Packaging (PLP). In a consortium of German partners from industry and research advanced technologies for PLP are developed. The project aims for an integrated process flow for SIPs with chips embedded into an organic laminate matrix. At first dies with Cu pillar structures are placed into openings of a laminate frame layer with very low coefficient of thermal expansion (CTE). They are embedded by vacuum lamination of thin organic films, filling the very small gap down to 15 μm between chips and frame. The frame provides alignment marks for a local registration of following processes. The ridged frame limits die shift during embedding and gives a remarkable handling robustness. Developments are initially performed on a 305×256mm2 panel format, aiming for a final size of 610×615 mm2. On the top side of embedded chips, a 20μm dielectric film is applied. The goal is to avoid additional via formation and to realize a direct connection between the Cu pillar of the die and the RDL The RDL formation is based on semi-additive processing. Therefore a Ti or TiW barrier and Cu seed layer is sputtered. Subsequently a 7μm photoresist is applied and exposed by a newly developed Direct Imaging (DI) system. Lines and spaces of 4μm were achieved with high yield. In the following, Cu is simultaneously electroplated for the via contacts and interconnects traces. Finally, the photo resist is stripped and the TiW barrier and Cu seed layers are etched. The goal of the development is to provide a technology for a high-density RDL formation on large panel sizes. The paper will discuss the new developments in detail, e.g. the influence of most significant process parameters, like lithographical resolution, minimum via diameter and the placement and alignment accuracy on overall process yield.

Through Silicon Via Technology: Cost effective Cu-TSV Interconnects by EMC3D and Technical Challenges with Cu-TSV

2010 ◽  
Vol 2010 (DPC) ◽  
pp. 000425-000445
Author(s):  
Paul Siblerud ◽  
Rozalia Beica ◽  
Bioh Kim ◽  
Erik Young
Keyword(s):  
Low Cost ◽  
Cost Effective ◽  
High Yield ◽  
Integrated Process ◽  
Wafer Level ◽  
Through Silicon Via ◽  
Wafer Level Packaging ◽  
Current State ◽  
Future Technologies ◽  
Ic Technology

The development of IC technology is driven by the need to increase performance and functionality while reducing size, power and cost. The continuous pressure to meet those requirements has created innovative, small, cost-effective 3-D packaging technologies. 3-D packaging can offer significant advantages in performance, functionality and form factor for future technologies. Breakthrough in wafer level packaging using through silicon via technology has proven to be technologically beneficial. Integration of several key and challenging process steps with a high yield and low cost is key to the general adoption of the technology. This paper will outline the breakthroughs in cost associated with an iTSV or Via-Mid structure in a integrated process flow. Key process technologies enabling 3-D chip:Via formationInsulator, barrier and seed depositionCopper filling (plating),CMPWafer thinningDie to Wafer/chip alignment, bonding and dicing This presentation will investigate these techniques that require interdisciplinary coordination and integration that previously have not been practiced. We will review the current state of 3-D interconnects and the of a cost effective Via-first TSV integrated process.

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