Ultrapure Water Particle Counting
Ultrapure water particle counting is critical for purity of final product.
The smelting and refining industry uses clean water to produce electronic-grade chemicals. Ultra pure water is integral to various manufacturing processes, including mixing raw materials, rinsing wafers, and supporting heating and cooling operations. Precise dilution with purified water ensures that process chemicals meet the required specifications. Particle monitoring and controlling impurities in the process chemicals used in manufacturing microelectronics is essential to ensure reliable chemical reactions and the final product’s quality and integrity. This paper explores the application of a high-sensitivity ultrapure water particle counter (Ultra DI® 20 Plus) to optimize ultrapure water (UPW) filtration performance in copper smelting and refining operations, and it demonstrates how sulfuric acid, a by-product of the process, can be refined to meet the high purity standards required by the semiconductor industry.
Production of Electronic-Grade Sulfuric Acid from Copper Smelting
As the semiconductor industry advances towards sub-10nm technology nodes, its processes demand increasingly high-quality, particle-free chemicals, including sulfuric acid. Ultrapure water (UPW) plays a critical role in producing high-quality sulfuric acid, making ultrapure water particle counting essential to monitor and control nanoparticles in the UPW source to maintain desired particle cleanliness levels and identify and mitigate contaminant sources.
While sulfuric acid is a by-product of the copper smelting process, the acid obtained from copper smelting does not meet the stringent standards of particle cleanliness required in semiconductor manufacturing. To achieve the cleanliness demanded by semiconductor fabs, the quality of the raw materials used to produce the acid must be carefully managed. This study focuses on improving ultrapure water particle counting to meet these requirements.
Sulfur Dioxide and the Copper Smelting Process
One step in the processing of copper is roasting, where an ore is heated in the presence of oxygen. Sulfur dioxide (SO2) is a by-product of roasting chalcopyrite, a copper iron sulfide mineral that is a primary source of copper and sulfur. When the chalcopyrite is roasted, sulfur from the mineral is oxidized to produce sulfur dioxide gas [1]:
The sulfur dioxide (SO2) generated during the smelting process can be used to produce sulfuric acid (H₂SO₄) via a method known as the contact process [2]. The contact process is the most widely adopted method for the industrial production of sulfuric acid. The acid produced in this way is widely utilized for fertilizer production, metal leaching, semiconductor manufacturing, and other industrial applications. The Lurgi and Monsanto double-contact process [3] is recognized for producing high-quality sulfuric acid through its precise, computer-controlled processes.
Download this paper to learn about
the contact process of producing sulfuric acid and how particle counters can provide a valuable tool for process chemical and semiconductor manufacturers to control and optimize the quality of their ultrapure water.
