Diamond Becomes An Ideal Material For Preparing Semiconductor Substrates

With the development of integration and miniaturization of semiconductor electronic devices, diamond's excellent thermal and electrical conductivity has become an ideal material for preparing semiconductor substrates. In order to meet the requirements of the semiconductor industry for high precision and high reliability performance of electronic devices, it is necessary to polish the surface of diamond. However, the high hardness, high wear resistance, and high chemical inertness of diamond make diamond processing face many difficulties. Existing diamond polishing technologies have their own advantages and disadvantages, and there is an urgent need for a diamond surface polishing technology that can achieve smoothness, flatness, and low damage while ensuring efficiency. Therefore, this article reviews the relevant literature on diamond polishing technology at home and abroad, summarizes the principles and advantages and disadvantages of mechanical polishing, thermochemical polishing, chemical mechanical polishing, plasma etching polishing, laser polishing and other technologies. For future diamond polishing technology, it should develop towards the combination of multiple technologies and the direction of intelligence, precision and environmental protection, thereby expanding the application scope of diamond materials.

 

In recent years, with the rapid development of 5G and artificial intelligence, their internal electronic components have been increasingly moving towards precision, integration, and miniaturization. Electronic devices are constantly shrinking, and the accumulation of heat generated during circuit operation can affect the operation of electronic devices and even cause damage. How to solve their heat dissipation problems and ensure the stable operation of the system is becoming increasingly important. At room temperature, diamond has a thermal conductivity greater than 2000 Wm-1K-1, excellent dielectric properties, and a low coefficient of thermal expansion (as shown in Table 1), making it an ideal heat dissipation material for manufacturing semiconductor devices. However, due to the uneven thickness, random crystal orientation, and rough surface with high internal stress that often occur during the growth process of diamond, as well as the high hardness, wear resistance, and chemical inertness of diamond materials, diamond processing is extremely difficult. Therefore, polishing techniques and equipment related to diamonds have always been a focus of attention in both academia and industry.

 

Various polishing techniques have been developed to meet the requirements of smooth, flat, and low damage diamond surfaces. The commonly used methods include mechanical polishing (MP), thermochemical polishing (TCP), chemical mechanical polishing (CMP), plasma etching polishing (PEP), laser polishing (LP), etc. However, each of the above methods has its own limitations, and there is currently no polishing technology that can simultaneously achieve high efficiency and high surface quality, which is an urgent problem that needs to be solved in industry.

Therefore, based on the current diamond polishing technology, starting from the equipment, principles, polishing efficiency, surface quality and other aspects of each polishing technology, the advantages and disadvantages of various polishing technologies are summarized, and the future development direction of diamond semiconductor substrate polishing technology is discussed.