This study introduces an enhanced thermal management strategy for efficient heat dissipation from GaN power amplifiers with high power densities. The advantages of applying an advanced liquid-looped silicon-based micro-pin fin heat sink (MPFHS) as the mounting plate for GaN devices are illustrated using both experimental and 3D finite element model thermal simulation methods, then compared against traditional mounting materials. An IR thermography system was equipped to obtain the temperature distribution of GaN mounted on three different plates. The influence of mass flow rate on a MPFHS was also investigated in the experiments. Simulation results showed that GaN device performance could be improved by increasing the thermal conductivity of mounting plates’ materials. The dissipated power density of the GaN power amplifier increased 17.5 times when the mounting plate was changed from LTCC (Low Temperature Co-fired Ceramics) (k = 2 Wm⁻¹ K⁻¹) to HTCC (High-Temperature Co-fired Ceramics) (k = 180 Wm⁻¹ K⁻¹). Experiment results indicate that the GaN device performance was significantly improved by applying liquid-looped MPFHS, with the maximum dissipated power density reaching 7250 W/cm². A thermal resistance model for the whole system, replacing traditional plates (PCB (Printed Circuit Board), silicon wafer and LTCC/HTCC) with an MPFHS plate, could significantly reduce θ_js (thermal resistance of junction to sink) to its theoretical limitation value.

With the development of integrated circuits, high power, and high integration chip array devices are facing the requirements of high heat flux and temperature uniformity. The micro-channel heat sink can meet the heat dissipation requirements of chip array devices with high heat flux, and the flow channel with fractal structure can achieve high temperature uniformity of chip array. In this study, the H-shaped fractal micro-channel structure was proposed to cooling the 4?4 chip (1 ? 1 mm) array. The interior fillet structure was introduced to optimize T-shaped and L-shaped corner structures in the fractal channel. The simulation results show that the overall pressure drop of micro-channel heat sink with is reduced 18.7%, and the maximum temperature difference of 4?4 chip array is less than 1.2? at 1000 W/cm2. The micro-channel heat sink with interior fillet structure interior fillet structure was fabricated and assembled, and the hydro-thermal performance was characterized by thermal test chip at different flow rates and heat fluxes. The experimental results show that the standard deviation of temperature of 4?4 chip array is less than 3.5? at 1000 W/cm2 and 480 ml per minute. The error between experimental and simulation data is within ?1.5%, which proves the reasonability of CFD modelling and simulation. Furthermore, the results demonstrate that by introducing interior fillet structure into the T-shaped and L-shaped structures could reduce pumping power and improve temperature uniformity of chip array, which can be applied to improve the performance of the chip array devices with high heat flux.

The development of semiconductor processes and advanced packaging technology has promoted significant advancements in the miniaturization and integration of electronic devices and systems. However, these developments present substantial challenges to the thermal and stress design of current chips, necessitating novel approaches to address these issues. Traditional finite element simulation-assisted design methods have proven inadequate in meeting the demands of highly integrated electronic devices and microsystems due to their inability to effectively simulate the integration process, cross-scale, and multi-physical field coupling. To address these challenges and shorten the design and development period of electronic devices and microsystems, rigorous thermal and stress testing and analyses must be conducted. A promising approach is the utilization of TTC (thermal test chip) technology, a novel in situ testing method, as the primary tool for thermal/stress testing and analyses of the internal interfaces of electronic devices and microsystems. This technology has emerged as a crucial element in validating thermal/stress processes during packaging, as well as in the design of effective heat dissipation solutions. This paper is structured as follows: first, it introduces the principle of thermal test chips; second, it summarizes the domestic and international research progress and index parameter comparison of thermal test chips, as well as the application progress in chip packaging and heat dissipation; and finally, it looks forward to the application prospect of thermal test chips in microsystem design and advanced packaging.

Further development of integrated circuits is greatly limited by the thermal problems inherent to chips. To eliminate the large thermal resistance between the contact surfaces of the components, thermal interfacial material (TIM) is widely used to enhance the thermal performance of packages. However, the existing TIM materials have performance problems such as low thermal conductivity, internal structural defects, and aging behavior and delamination after long-term use. These shortcomings have become important factors that hinder the improvement of heat dissipation of chips. This paper proposes a low junction-to-case thermal resistance packaging method of introducing a fluid phase change in the package, which utilizes latent heat to efficiently transfer heat while eliminating the TIM layer and the thermal resistance introduced by it. Theoretically, the novel method has the potential to obtain a low thermal resistance of 0.031°C/W and greatly reduces the thermal resistance of the inner structures of the package except for the die and lid. A Si-Al package sample with a total thickness of 2.9 mm was fabricated, and the influence of phase-change heat transfer on the thermal resistance of the junction case was tested with a silicon-based thermal test chip as the heat source. In the experiment, this method reduces the thermal resistance of the sample from ~0.46°C/W to ~0.1°C/W under a 3-W power input.

When chips perform numerous computational tasks or process complex instructions, they generate substantial heat, potentially affecting their long-term reliability and performance. Thus, accurate and effective temperature measurement and management are crucial to ensuring chip performance and lifespan. This paper presents a multi-channel temperature measurement system based on a diode temperature-sensitive array thermal test chip (TTC). The thermal test chip accurately emulates the heat power and thermal distribution of the target chip, providing signal output through row and column address selection. The multi-channel temperature measurement system centers around a microcontroller and includes voltage signal acquisition circuits and host computer software. It enables temperature acquisition, storage, and real-time monitoring of 16 channels in a 4 × 4 array thermal test chip. During experiments, the system uses a constant current source to drive temperature-sensitive diodes, collects diode output voltage through multiplexers and high-precision amplification circuits, and converts analog signals to digital signals via a high-speed ADC. Data transmission occurs via the USB 2.0 protocol, with the host computer software handling data processing and real-time display. The test results indicate that the system accurately monitors chip temperature changes in both steady-state and transient thermal response tests, closely matching measurements from a semiconductor device analyzer, with an error of about 0.67%. Therefore, this multi-channel temperature measurement system demonstrates excellent accuracy and real-time monitoring capability, providing an effective solution for the thermal design and evaluation of high power density integrated circuits.