Development of Backside Buried Metal Layer Technology for 3D-ICs

2019 ◽  
Vol 2019 (1) ◽  
pp. 000268-000273
Author(s):  
Naoya Watanabe ◽  
Yuuki Araga ◽  
Haruo Shimamoto ◽  
Katsuya Kikuchi ◽  
Makoto Nagata

Abstract In this study, we developed backside buried metal (BBM) layer technology for three-dimensional integrated circuits (3D-ICs). In this technology, a BBM layer for global power routing is introduced in the large vacant area on the backside of each chip and is parallelly connected with the frontside routing of the chip. The resistances of the power supply (VDD) and ground (VSS) lines consequently decrease. In addition, the BBM structure acts as a decoupling capacitor because it is buried in the Si substrate and has metal–insulator–silicon structure. Therefore, the impedance of power delivery network can be reduced by introducing the BBM layer. The fabrication process of the BBM layer for 3D-ICs was simple and compatible with the via-last through-silicon via (TSV) process. With this process, it was possible to fabricate the BBM layer consisting of electroplated Cu (thickness: approximately 10 μm) buried in the backside of the CMOS chip (thickness: 43 μm), which was connected with the frontside routing of the chip using 9 μm-diameter TSVs.

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
Weijun Zhu ◽  
Gang Dong ◽  
Yintang Yang

The design of three-dimensional (3D) power delivery network (PDN) is constrained by both power and thermal integrity. Through-silicon via (TSV) as an important part of transmission power and heat in stack, the rational design of TSV layout is particularly important. Using minimal TSV area to achieve the required 3D PDN is significant to reduce manufacturing costs and increase integration. In this paper, we propose electrical and thermal models of 3D PDN, respectively, and we use them to solve the 3D voltage drop and temperature distribution problems. The accuracy and efficiency of our proposed methods are demonstrated by simulation measurement. Combining these two methods, a layer-based optimization solution is developed and allows us to adjust the TSV density for different layers while satisfying the global power and thermal constraints. This optimization is scalable and has the same guiding value for multichip stacks with different functions and constraints. A setup of four-chip stack is used to demonstrate the feasibility of this optimization and a large TSV area saving is achieved by this method.


2019 ◽  
Vol 16 (10) ◽  
pp. 909-916
Author(s):  
Jin-Hong Park ◽  
Munehiro Tada ◽  
Hyun-Yong Yu ◽  
Duygu Kuzum ◽  
Yeul Na ◽  
...  

Author(s):  
Je-Hyoung Park ◽  
Ali Shakouri ◽  
Sung-Mo Kang

CMOS VLSI technology has been facing various technical challenges as the feature sizes scale down. To overcome the challenges imposed by the shrink of the conventional on-chip interconnect system in IC chips, alternative interconnect technologies are being developed: one of them is three dimensional chips (3D ICs). Even though 3D IC technology is a promising solution for interconnect bottlenecks, thermal issues can be exacerbated. Thermal-aware design and optimization will be more critical in 3D IC technology than conventional planar IC technology, and hence accurate temperature profiles of each active layer will become very important. In 3D ICs, temperature profile of one layer depends not only on its own power dissipation but also on the heat transferred from other layers. Thus, thermal considerations for 3D ICs need to be done in a holistic manner even if each layer can be designed and fabricated individually. Conventional grid-based temperature computation methods are accurate but are computationally expensive, especially for 3D ICs. To increase computational efficiency, we developed a matrix convolution technique, called Power Blurring (PB) for 3D ICs. The temperature resulting from any arbitrary power dissipation in each layer of the 3D chip can be computed quickly. The PB method has been validated against commercial FEA software, ANSYS. Our method yields good results with maximum error less than 2% for various case studies and reduces the computation time by a factor of ∼ 60. The additional advantage is the possibility to evaluate different power dissipation profiles without the need to re-mesh the whole 3D chip structure.


Author(s):  
Hai Wei ◽  
Tony F. Wu ◽  
Deepak Sekar ◽  
Brian Cronquist ◽  
Roger Fabian Pease ◽  
...  

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