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In July 2026, another important progress was made in the field of domestic organosilicon special intermediates: the terminal-vinyl low-crosslinking silicone oil product specially customized for advanced semiconductor packaging officially achieved 10,000-ton mass production. The vinyl groups of this product are 100% accurately distributed at both ends of the linear polysiloxane molecular chain, the molecular structure regularity reaches 99.4%, the volatile content is lower than 12ppm, and the vinyl content error is controlled within ±0.015%. The successful mass production of this product fills the long-term technical gap in high-end categories of domestic terminal-vinyl silicone oil, directly solves the "stuck neck" problem of the core raw material for low-stress organosilicon underfill for 2.5D/3D advanced packaging in China, and provides key material guarantee for the supply chain security of domestic new-generation AI chips, vehicle-mounted power semiconductors and other industries.
Terminal-vinyl silicone oil is a vinyl silicone oil with a highly special structure. Different from ordinary vinyl silicone oil with vinyl groups distributed on side chains, its two vinyl groups are accurately located at both ends of the linear polysiloxane molecule. The entire molecule presents an almost perfect straight-chain structure without random distribution of side active groups. This unique molecular structure allows it to form a completely linearly extended crosslinking network when participating in the silicon-hydrogen addition reaction, completely avoiding the local three-dimensional excessive crosslinking problem that easily occurs when ordinary side-vinyl silicone oil is crosslinked. The prepared addition-cured silicone gel has extremely low internal stress, extremely high light transmittance, nearly zero shrinkage and extremely stable dielectric properties, and is an irreplaceable core raw material in the current advanced semiconductor packaging field. For a long time in the past, the traditional alkali-catalyzed end-capping process was commonly used in the production of domestic terminal-vinyl silicone oil, which could not accurately control the end-capping position of vinyl groups. The produced products were mixed with a large number of impurity components with side-chain vinyl groups, and the molecular structure regularity was less than 78%, which could not meet the strict application requirements of advanced semiconductor packaging. Previously, the ultra-high-purity terminal-vinyl silicone oil used in domestic advanced packaging fields was almost completely dependent on imports. Not only was the procurement cost 7-9 times that of ordinary vinyl silicone oil, but it also long faced risks such as unstable supply and embargo of special specifications, which has seriously restricted the pace of China's semiconductor industry upgrading to advanced processes below 7nm.
The terminal-vinyl low-crosslinking silicone oil product that has achieved mass production this time has achieved two subversive innovations in core technologies. On the one hand, the precise anchoring living polymerization technology of vinyl double end caps was innovatively developed. The technical team designed a brand-new directional end-capping reaction system for double-terminal vinyl groups. By matching the double-terminal vinyl end-capping agent and cyclic siloxane monomers at the molecular level accurately in the initial stage of the reaction, and cooperating with a novel controllable ring-opening catalyst, the polymerization reaction extends along the linear direction from beginning to end, completely avoiding the random generation of side-chain vinyl groups during the polymerization process. The molecular structure regularity of the final product reaches 99.4%, and the proportion of terminal vinyl groups exceeds 99.2%, completely solving the industry problem of messy product components in traditional processes. On the other hand, a non-damaging deep devolatilization process for terminal-vinyl systems was developed. Aiming at the characteristics of high linearity of the molecular chain of terminal-vinyl silicone oil and highly concentrated boiling point distribution, the team innovatively adopted a multi-stage series high-vacuum falling film devolatilization coupled with inert gas countercurrent purging process. The small molecule devolatilization is completed under the mild temperature condition of the whole process below 85°C, completely avoiding the polymerization deactivation of vinyl groups in a high-temperature environment, and the total volatile content of the final product is controlled below 12ppm. At the long-term working temperature of 130°C for semiconductors, no small molecular substances will precipitate and pollute the chip circuits.
At present, this domestically produced terminal-vinyl low-crosslinking silicone oil has completed batch application verification in multiple advanced semiconductor scenarios. In the field of 2.5D/3D advanced packaging, the chip underfill prepared with this product has a curing shrinkage rate of less than 0.1%, and the internal stress is only 1/5 of that of traditional underfill materials, which will not cause stress damage to the precision chip bumps of processes below 3nm. At the same time, the dielectric constant of the product is stably maintained at 2.6, and the dielectric loss is lower than 0.0018, which fully meets the strict requirements of high-computing-power AI chips for high-speed signal transmission. Related products have been widely used in the new-generation advanced packaging production lines of leading domestic chip packaging enterprises. In the field of vehicle-mounted power semiconductors, the potting adhesive prepared with this terminal-vinyl silicone oil has extremely high thermal shock resistance. After 1500 temperature cycle tests from -55°C to 150°C, no cracking and interface debonding occur in the adhesive layer, and it has been batch applied in the packaging links of IGBT and SiC power modules for new energy vehicles. In the field of optoelectronics, the optical-grade organosilicon packaging adhesive prepared with this high-purity terminal-vinyl silicone oil has a 400nm visible light transmittance of 99.3%. After 3000 hours of strong blue light irradiation, the light transmittance retention rate still exceeds 98.5%, which perfectly adapts to the packaging requirements of optoelectronic devices such as Mini/Micro LEDs and optical windows of LiDAR. In the field of MEMS sensors, the packaging protective adhesive prepared with this product has extremely low modulus and extremely high dimensional stability, which will not cause additional stress interference to the precision micro-mechanical structures, and has been widely used in the packaging protection of various MEMS sensors for smartphones and autonomous driving.
According to the latest industry statistics, the market demand for domestic semiconductor-grade terminal-vinyl silicone oil in 2026 has increased by 217% year-on-year compared with 2025. The successful mass production of domestic products this time has directly broken the long-term monopoly of overseas enterprises in this field. The core raw material procurement cost for downstream advanced packaging enterprises has decreased by 72%, and the product delivery cycle has been shortened from the original 9 months to 5 days. With the continuous release of subsequent supporting production lines, it is expected that by 2027, the domestic market share of domestically produced semiconductor-grade terminal-vinyl silicone oil will reach more than 92%. It will not only completely solve the core raw material supply risk of the domestic semiconductor industry, but also promote China's advanced packaging material industry to gain stronger competitive advantages in the global market.
