Characterizing the Retention of UPW Filters Using a Polydispersed Silica Challenge

Constant developments in the microelectronics industry, with finer line widths and the requirement of essentially particle-free water, also brings with it many challenges involving the conservation and reuse of water, treatment of growing streams of wastewater produced from high-purity water from processes such as CMP, photolithography and etchant rinsing. This article provides an overview of featured keynote speakers, technical presentations on UPW and process water/wastewater as well as Roundtable Networking session at the UPW Micro 2015 conference.

The complexity of integrated circuit (IC) manufacturing for advanced nodes, paired with the growing demand for higher yields and lower defectivity, requires close alignment among industry stakeholders. New systematic improvements of system design, material choice and quality assurance methodologies are needed to minimise every possible source of contamination and variation in the manufacturing process. An extensive collaborative effort between SEMI Standards Task Forces and IRDS roadmap teams, representing the IC manufacturing supply chain, is focused on developing industry best practices to enable proactive yield management. As a result, relevant SEMI Standards are being revised to focus on the quality of UPW and liquid chemicals, design and operation of related systems, qualification of polymer assemblies and process critical materials and components. This article was originally published in the Ultrapure Micro Journal in March 2019.

This article provides an overview of the biggest challenge of UPW technology – particle control. The latest semiconductor technologies require near particle-free water, where the “killer” particle size is far below the size that UPW metrology can effectively detect. Also, current advanced treatment methods cannot guarantee reliable removal of killer-sized particles. The quality of the high-purity materials used downstream of the final filters has not typically been tested for shedding of the “killer” particles. Consequently, the semiconductor industry requires a comprehensive approach for the particle control. A new approach should include mitigating particle occurrence and continuously improving the technologies used in UPW polish and distribution systems. Such an approach should also include extensive use of SEMI standards to improve the quality of the materials used; a new way to engineer solutions related to system-configuration and system design; improved process control; and a careful review of critical operational decisions. Collaboration throughout the industry via IRDS and SEMI Standards is key to enabling such systematic improvement, and overcoming the metrology and other constraints. This article was originally published in the Ultrapure Micro Journal in November 2017.

Particles in ultrapure water (UPW), used during the manufacture of microcircuits on semiconductor wafers, can deposit onto the wafer surface thereby causing decreased yield and reliability of the microcircuits. As microcircuit future sizes continue to decrease, understanding the ability of a filter to capture and retain these particles becomes increasingly important and challenging. In 2013, SEMI C79-0113, “Guide to Evaluate the Efficacy of Sub-15 nm Filters used in Ultrapure Water (UPW) Distribution System” was published. This document provides a SEMI recommended method for evaluating the efficacy of filter elements used to remove particles in UPW fluid streams. Since the release of this guide, the method has been enhanced to allow quantification of particle retention over a broad size range. This was accomplished by adding larger silica particles to the Ludox® SM30 silica specified by SEMI C79 resulting in a poly-dispersed silica challenge. A particle size distribution (PSD) slope of -2 (log-log) was selected so the challenge would more closely mimic a PSD typically found in UPW, yet still have sufficient large particles to measure a log retention value of 2 or 99% retention. This silica challenge has been designated as an “area-weighted challenge”. The use of this enhanced method has resulted in some interesting observations including indication of a most penetrating particle size similar to what is observed in gas filtration. The presence of a most penetrating particle size would indicate that retention mechanisms other than sieving are active, particularly for particles smaller than 30 nm. This paper will review the enhancements made to the test method, review the retention data from a number of filter types and manufacturers, and discuss the implications for filters used in UPW. This article was originally published in the Ultrapure Micro Journal in November 2017.

This presentation was given at the Ultrapure Micro 2020 annual conference. It was presented in the Ultrapure Water Production track, as part of the UPW Contamination Control session.

This presentation was given at the Ultrapure Micro 2019 annual conference. It was presented during the Learning Series, as part of the Ultrapure Water Production track.

This presentation was given at the Ultrapure Micro 2018 annual conference. It was presented as a Keynote presentation.

This presentation was given at the Ultrapure Micro 2017 annual conference. It was presented in the Ultrapure Water Production track, as part of the Enabling Advanced Fab Needs session.

This presentation was given at the Ultrapure Micro 2017 annual conference. It was presented as a Keynote presentation.

This presentation was given at the Ultrapure Micro 2016 annual conference. It was presented as a Keynote presentation.