The semiconductor industry has strict requirements for water quality, and ultrapure water, as the core consumable for production, directly affects the chip yield rate in terms of its quality. Semiconductor ultrapure water needs to meet multidimensional indicators: the resistivity needs to reach 18.2M Ω· cm (25 ℃) or above to ensure extremely low ion content; TOC (Total Organic Carbon) should be controlled below 0.5ppb to avoid affecting lithography accuracy; Particles larger than 0.05 microns should not exceed 100 per liter to prevent lithography defects; Dissolved oxygen below 1 ppb inhibits bacterial growth and oxide layer formation.
Ultra pure water application runs through the entire semiconductor production process: the wafer preparation process is used for cleaning and impurity removal to ensure surface crystallinity; Clean the template and wafer in the photolithography process to ensure precise patterns; The etching and mechanical polishing processes play a cooling and cleaning role to maintain process consistency; Clean metal thin films during the electrochemical deposition stage to ensure deposition accuracy; It can also be used for equipment cooling and laboratory experiments to ensure reliable data.
Ultra pure water source comes from tap water and requires multiple processes for deep treatment: the front-end uses ACF, UF, RO, EDI and other processes to reduce TOC from 1-3 ppm in tap water to 10-30 ppb; Further reduced to ≤ 0.5ppb through TOC-UV lamp device, ultimately meeting the standard. In terms of detection, particles are monitored using a liquid particle counter, TOC、 The indicators such as resistivity, dissolved oxygen, pH, etc. are detected in real-time through online monitoring devices (such as electrochemical instruments), and some scenarios require integrated systems to achieve dynamic water quality control.
The monitoring cycle should be set based on the working conditions and changes in water quality, with regular sampling and analysis to promptly identify water quality issues and avoid chip quality degradation or production loss caused by excessive total organic carbon, high dissolved oxygen, and excessive particulate matter. With the reduction in size and improvement in precision of semiconductor components, ultra pure water monitoring requires continuous upgrading of detection accuracy and technology (such as remote monitoring) to meet the increasingly stringent water quality requirements of the industry.