Organic/Inorganic Alternating-Structure Thin-Film Process and Control for Encapsulation of Machine Parts

Keywords: Organic electronic device packaging, PECVD, organic/inorganic alternating multilayer films, water and oxygen barrier performance. In recent years, organic electronic devices have experienced rapid development and have become one of the major highlights of the electronics industry in the 21st century. According to a market analysis report by the specialized agency NanoMarkets, the future output value of the organic electronics industry is projected to exceed 300 billion U.S. dollars. Organic electronic devices are characterized by their light weight, thinness, and flexibility. Organic electronic device packaging requires low-temperature processing, flexibility, and thin-film encapsulation. Alternating multilayer films are considered the most effective approach for thin-film encapsulation. There are various methods available for fabricating such films; however, these methods must meet the requirements of low-temperature operation, high density, and flexibility.

　　Keywords: Organic electronic device encapsulation, PECVD, organic/inorganic alternating multilayer films, water and oxygen barrier performance

　　Organic electronic devices have experienced rapid development in recent years and have become one of the major highlights of the electronics industry in the 21st century. According to a market analysis report by the specialized agency NanoMarkets, the future output value of the organic electronics industry is projected to exceed 300 billion U.S. dollars. Organic electronic devices are characterized by their light weight, thinness, and flexibility. Therefore, packaging for organic electronic devices requires low-temperature, flexible, and thin-film encapsulation technologies. The alternating-layer film structure is considered the most effective approach for thin-film encapsulation. There are various methods for preparing such films; however, only the alternating organic/inorganic film structure can currently meet the stringent requirements of low temperature, high density, and flexibility. Our research group has independently designed and built an ICP-PECVD system capable of achieving low-temperature growth (below 120°C) of homogeneous, co-deposited alternating organic/inorganic films within the same chamber. Using this equipment, we have conducted an in-depth study on the growth of alternating organic/inorganic films, examining the effects of parameters such as deposition temperature, RF power, process gas flow rates and ratios, and deposition pressure on the properties of individual inorganic or organic layers. We have also comprehensively investigated how factors like the interface characteristics of the alternating structure and the number of alternating layers influence the water and oxygen barrier performance. The experimental results show that the inorganic layer serves primarily as the main barrier against water and oxygen molecules, while the organic layer mainly enhances flexibility and relieves stress in the inorganic layer. Moreover, defects and density in the inorganic layer significantly affect the overall water and oxygen barrier performance of the encapsulation structure, and the interface characteristics of the alternating structure play a crucial role in determining the barrier performance. A single-cycle alternating organic/inorganic structure achieves a water and oxygen barrier rate of 10⁻² g/m²·day, whereas a four-cycle alternating organic/inorganic structure attains a barrier rate as low as 10⁻⁵ g/m²·day.

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