The FinFET technology is regarded as a better alternative for modern high-performance and low-power integrated-circuit design due to more effective channel control and lower power consumption. However, the gate-misalignment problem resulting from process variation and the parasitic resistance resulting from interconnecting wires based on the FinFET technology becomes even more severe compared with the conventional planar CMOS technology. Such gate misalignment and unwanted parasitic resistance may increase the threshold voltage and decrease the drain current of transistors. When applying the FinFET technology to analog circuit design, the variation of drain currents can destroy current-ratio matching among transistors and degrade circuit performance. In this article, we present the first FinFET placement and routing algorithms for layout generation of a common-centroid FinFET array to precisely match the current ratios among transistors. Experimental results show that the proposed matching-driven FinFET placement and routing algorithms can obtain the best current-ratio matching compared with the state-of-the-art common-centroid placer.

The FinFET technology has been regarded as a better alternative among different device technologies at 22nm node and beyond due to more effective channel control and lower power consumption. However, the gate misalignment problem resulting from process variation based on the FinFET technology becomes even severer compared with the conventional planar CMOS technology. Such misalignment may increase the threshold voltage and decrease the drain current of a single transistor. When applying the FinFET technology to analog circuit design, the variation of drain currents will destroy the current matching among transistors and degrade the circuit performance. In this paper, we present the first FinFET placement technique for analog circuits considering the impact of gate misalignment together with systematic and random mismatch. Experimental results show that the proposed algorithms can obtain an optimized common-centroid FinFET placement with much better current matching.

Analog layout design has been a manual, time-consuming, and error-prone task for decades. To speed up layout design time for a new design, analog layout designers prefer referring to legacy designs and layouts rather than starting from scratch, or thoroughly applying placement and routing tools because legacy layouts contain pretty much design expertise. Motivated by such layout design process, this paper presents the first knowledge-based physical synthesis methodology to generate new layouts by integrating existent design expertise. The proposed approach can automatically analyze legacy design data including circuits, layouts, and constraints, extract matched sub-circuits between new and legacy designs, and generate multiple layouts for the new design by utilizing the quality-approved legacy layouts as much as possible. Experimental results show that the proposed methodology can achieve high layout reusage rate, and hence the designers' layout preference can be successfully reserved.

Although several Engineering Change Order (ECO) routers had been proposed to obtain a routing solution based on different design objectives, mask re-spin cost still cannot be effectively reduced because the ECO routing problem is handled in a sequential manner. This paper presents a three-stage ECO routing flow which can simultaneously route all ECO nets while considering routing layer minimization. Experimental results demonstrate that our proposed ECO routing flow can effectively reduce the number of changed masks with only negligible wirelength and via overhead.

Mobility is the primary device parameter affecting circuit performance in flexible thin-film transistor (TFT) technologies, and is particularly sensitive to the change of mechanical strain and temperature. However, existing algorithms only consider the impact of mechanical strain in cell placement of flexible TFT circuits. Without taking temperature into consideration, mobility may be dramatically decreased which leads to circuit performance degradation. This article presents the first work to minimize the mobility variation caused by the change of both mechanical strain and temperature. Experimental results show that the proposed algorithms can effectively and efficiently reduce the increasing critical path delay.

Although modern analog placement algorithms aimed to minimize area and wirelength while satisfying symmetry, proximity, and other placement constraints, the generated layout does not reflect the circuit performance very well because of the routing-induced parasitics on the critical current/signal paths. To simultaneously consider symmetry, wirelength, area utilization, and current/signal paths during analog placement, this paper explores the feasibilities of symmetry islands and monotonic current paths in slicing trees for analog placement optimization. Experimental results show that the proposed formulation and algorithms can generate much more compact layouts resulting in similar or even better circuit performance compared with the previous work.

Mobility is the key device parameter to affect circuit performance in flexible thin-film transistor (TFT) technologies, and it is very sensitive to the change of mechanical strain and temperature. However, existing algorithms only consider the impact of mechanical strain in cell placement of flexible TFT circuit. Without taking temperature into consideration, mobility may be dramatically decreased which leads to circuit performance degradation. This paper presents the first work to reduce the mobility influence caused by the change of both mechanical strain and temperature. Experimental results show that the proposed algorithms can effectively reduce the chip temperature and the influence caused by mobility variation.

As process technologies advance to the subwavelength era, the 1-D design style is regarded as one of the most effective ways to continue scaling down the minimum feature size. To improve the printability of 1-D cell design, it is essential to insert dummy patterns and optimize line-end gap distribution for each layer. This paper presents novel 1-D cell generation algorithms that simultaneously minimize 1-D cell area and enhance the printability. Experimental results show that the proposed algorithms can effectively and efficiently reduce the number of diffusion gaps, minimize used routing tracks, insert sufficient dummy patterns, and eliminate stage-like line-end gaps without power and timing overhead. Consequently, the 1-D cell area is minimized and the printability of the cell is enhanced. To the best of our knowledge, this is also the first work in the literature that considers line-end gap distribution during 1-D cell generation.

Although modern analog placement algorithms aimed to minimize area and wirelength while satisfying symmetry, proximity, and other placement constraints, the generated layout does not reflect the circuit performance very well because of the routing-induced parasitics on the critical current/signal paths. This paper introduces the current-path constraints in analog placement, demonstrates their impact on circuit performance, and derives new problem formulation and algorithms to find placement solutions with monotonic current paths. Experimental results show that the proposed formulation and algorithms can generate compact layouts resulting in the even better circuit performance after performing post-layout simulation.