K-Patents Oy - semiconductor

K-Patents Applications in Semiconductor Industry Semiconductor and Microelectronics Fabrication: Wet Chemical Wafer Processing The K-Patents Semicon Refractometer measures real-time the liquid chemical concentrations in the semiconductor fabrication process, i.e. from chemical supplies down to fab in-line and tool in-situ chemical quality control. The concentration of dissolved solids is determined by making an optical measurement of the solution’s refractive index. The advantage of this principle is that the same instrument can be used to measure any chemical. The K-Patents Refractometer provides a continuous 4-20 mA or Ethernet signal and immediate feedback to the control system, if the chemical is out of the specifications. The K-Patents Refractometer is physically small and easy to install in the bulk chemicals dispense, and in point of use chemical blending, spiking and monitoring applications. Ref. Application Note 5.00.00 Bulk Chemical Delivery Systems Fabs with many products typically use a high number of different bulk chemicals. And since the predominant delivery method of chemicals in Fabs is by drum, every time a person handles a new drum there is a potential for human error. Occasionally, wafer defects occur due to wrong drum of chemical being dispensed onto the wafers. Therefore, the type of chemical should always be monitored and validated before it enters the process. With K-Patents technology, low and high concentration alarms can be configured to eliminate these defects caused by human errors in container handling or equipment failure at the distribution point. Ref. Application Note 5.00.10 Ref. Paper: In-Situ Chemical Monitoring in Semiconductor Fabrication Chemical Supplies To top of the page Anisotropic Etch of Silicon Wet etch is used to chemically remove layers (metal, silicon, photoresist) from the surface of a wafer. For instance, potassium hydroxide (KOH) is commonly used for etching Silicon. The etch rate of silicon in a KOH bath depends on the bath temperature and the KOH concentration. As etching progresses some KOH (namely OH^- ions) is consumed in the process. K-Patents Semicon Refractometer provides a real-time indication of the KOH concentration and helps to determine the correct etch end point. This way the bathlife can be increased. In some cases the bathlife can be doubled. Ref. Application Note 5.00.20 To top of the page
Post-Etch Wafer Cleaning: EKC in Spray Solvent Tools K-Patents Semicon Refractometer is used for concentration measurement of aqueous mixtures, such as EKC-265. EKC-265 is formulated to remove etching residues namely the remaining polymer material after the etching and the ashing operation (where the photoresist layer is removed). The purpose of the real-time in situ measurement is to determine the bath life. The water content of the rinsing bath starts from 18% and goes down to 13% where it stabilizes. The more water, the more aggressive the solution is. The refractometer provides a reliable indication of the bathlife, so that the bathlife can be extended, the wafer throughput can be increased and the overall chemical consumption can be reduced. Ref. Application Note 5.00.30 To top of the page Chemical Mechanical Planarization (CMP): Blending and Dispense of Hydrogen Peroxide H₂O₂ Slurry The CMP slurries, especially oxide polishing slurries commonly require mixing or dilution before use. It is essential to measure the H₂O₂ concentration in the mixed slurry, because altering the concentration of the slurry constituents will affect the chemical reaction rates and wafer polishing rate. Too much H₂O₂ can result in contamination of the wafer. K-Patents Semicon Refractometer is an in-line metrology device, which measures the H₂O₂ content of the slurry during blending and in the slurry dispense line. K-Patents measurement signal is not influenced by the entrapped air. Ref. Application Note 5.00.50 To top of the page
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