## 1 Introduction  
For several decades, the integration of electronic devices to improve system performance has accelerated rapidly. Due to the resulting miniaturization of semiconductor devices, thermal management issues related to electronic components have become increasingly important [1, 2]. Especially in small electronic devices, the generated heat significantly affects the efficiency degradation, lifetime, and overall performance. A previous study reported that even a small temperature rise of 10-15 \({}^{\circ}\)C in electronic devices reduces the life expectancy by 50% and decreases system reliability [3]. Therefore, heat dissipation control techniques are becoming more important than ever. In particular, to prevent abnormal temperature rises in such devices, it is necessary to lower the thermal resistance at the contact interface between a chip and heatsink by applying a thermal interface material (TIM). Such a material should have a high thermal conductivity, which decreases the thermal resistance between the chip and heat sink [4, 5, 6, 7, 8]. The primary requirements for TIM are high thermal conductivity and stability and low electric conductivity. Among them, high thermal conductivity is the most important parameter, and generally requires using a small loading fraction of fillers, which is becoming important for low-cost and high-efficiency devices [9]. Recently, polymer materials are widely used as TIMs because of their easy processing, light weight, and low cost. However, polymers generally have low thermal conductivity (\(\sim\)0.16 Wm\({}^{-1}\)K\({}^{-1}\)) due to the random arrangement of their macromolecular chains [10]. Recently, various research has been conducted to enhance the thermal conductivity of polymer [10; 11; 12; 13; 14; 15]. For example, [PERSON], et al. used a metal oxide (Al\({}_{2}\)O\({}_{3}\)) filler to enhance the thermal conductivity and explained the importance of using a nanosphere filler and nanosphere's morphology to reduce the phonon scattering between the fillers on an uneven surface [16]. [PERSON] et al. enhanced the thermal conductivity of polymer (\(\sim\)2.84 Wm\({}^{-1}\)K\({}^{-1}\)) using one-dimensional carbon fiber to make a thermal path [17]. However, current polymer-based TIMs do not satisfy the demands of various advanced devices due to the high loading fraction of fillers (\(>\)50 wt%), which can degrade the original electrical insulation while increasing the thermal conductivity [14]. Therefore, it is necessary to develop novel structures consisting of materials with low electrical conductivity to achieve efficient heat conduction with low loading of fillers. Among the generally used fillers, metal oxides such as alumina (Al\({}_{2}\)O\({}_{3}\)), copper oxide (CuO), and titanium-dioxide (TiO\({}_{2}\)) are cheaper and more stable with a lower electrical conductivity than other metals [16; 18]. Thus, they are less likely to cause electrical problems in electronic devices after the packaging process. In particular, TiO\({}_{2}\) not only has a low electrical conductivity due to its wide bandgap (\(\sim\)3.2 eV at room temperature), but also relatively high thermal conductivity [18; 19]. Although these advantages showcased TiO\({}_{2}\) as a potential candidate for TIM filler, few studies have been reported. In this study, we demonstrate the effective improvement of thermal conductivity of TIM by constructing a TiO\({}_{2}\) nanosphere (NS)-monolayer structure in a polymer. COMSOL Multiphysics simulations were conducted to explain the thermal conductivity enhancing effect of the monolayer structure, considering complex heat transfer such as conduction, convection, and thermal resistance.