Sintered Stainless Steel

Additionally, for semiconductor applications involving corrosive specialty gases, this product-thanks to its excellent resistance to halogens, acids, and alkalis-can operate stably over the long term in fluorine- and chlorine-based gas environments without being corroded by the medium and generating secondary impurities. Compared to organic filter media such as PTFE and glass fiber, its high-temperature resistance, aging resistance, and non-volatile properties make it perfectly suited for high-temperature gas processes, completely resolving the industry-wide challenge of gas contamination caused by the high-temperature decomposition of organic materials.

During continuous operation in a factory, CMP slurry is not a static system but constantly undergoes circulation, shearing, pressure changes, and chemical reactions. During this process, nanoparticles may gradually aggregate due to van der Waals forces, electrostatic shielding effects, or changes in the chemical environment, forming large agglomerates much larger than the original particles. Factors influencing agglomeration formation include high-speed shearing by the circulating pump leading to local dispersant failure; prolonged slurry storage time resulting in decreased colloidal stability; temperature changes altering the surface charge of particles; increased metal ion concentration in the slurry compressing the electric double layer and inducing particle aggregation; and air entering the circulation system forming microbubbles, promoting particle bridging.

Traditional polymer membranes primarily rely on two-dimensional membrane structures for surface retention. During filtration, particles tend to accumulate on the membrane surface, forming a cake layer, leading to a rapid increase in pressure differential. In contrast, NAVI titanium's sintered stainless steel employs a three-dimensional interconnected microporous structure. Its internal channels are interconnected, allowing particles to not only be retained on the surface but also gradually distribute along the channel depth, achieving typical depth filtration. This filtration method offers several significant advantages. First, the nano-slurry flows uniformly throughout the entire pore network, preventing the formation of localized high-speed scouring zones and reducing abrasive wear on the filter media. Second, larger agglomerated particles are preferentially retained at the channel inlets, while normal nanoparticles can pass through smoothly, thus not significantly altering the slurry particle size distribution.

Copper CMP is a key step in the Damascene (damascene interconnect) process. Its goal is to remove copper overplating while maintaining the copper filling in trenches and vias. Due to copper's high ductility and low hardness, it is susceptible to localized mechanical stress during CMP, making the particle state of the slurry particularly important for process stability. Copper CMP slurries typically use colloidal silica as the primary abrasive, with a particle size generally controlled between 30 and 80 nm, and are supplemented with chemical additives such as hydrogen peroxide and benzotriazole (BTA) to regulate oxidation and corrosion inhibition on the copper surface. The primary task of sintered stainless filters in copper CMP is to remove abnormal particles several times larger than the normal abrasive particle size, rather than intercepting all particles.

Tungsten CMP is primarily used for machining tungsten plugs in contact plugs and planar interconnects. Compared to copper, tungsten is harder, and the removal process relies mainly on a combination of chemical oxidation and mechanical grinding. Therefore, oxidants and high-hardness abrasives are typically added to the slurry. Tungsten CMP filters must withstand significantly higher levels of abrasion. Because the abrasive cutting power in the slurry is stronger, ordinary polymer filter media are prone to pore enlargement or membrane wear after long-term operation. This product, however, features an integral sintered metal skeleton, capable of withstanding continuous high-speed scouring and maintaining filtration accuracy over a long period. Tungsten CMP is highly sensitive to metallic impurities.

STI (Shallow Trench Isolation) CMP is mainly used to remove silicon oxide material after trench filling, achieving electrical isolation between transistors. Since STI directly affects subsequent gate formation, its planarization quality requirements are extremely high. STI slurries typically use nano-cerium oxide (CeO₂) as the main abrasive. Its particles have high chemical activity and can synergistically react with the silica surface, improving polishing efficiency. A characteristic of cerium oxide slurries is that the particles have a strong surface charge, making them prone to agglomeration due to pH or ion concentration changes.