Separation and Purification Technology 76 (2010) 44–51 Contents lists available at ScienceDirect Separation and Purification Technology journal homepage: www.elsevier.com/locate/seppur Ultrapurification of hydrogen peroxide solution from ionic metals impurities to semiconductor grade by reverse osmosis R. Abejón, A. Garea ∗ , A. Irabien Departamento de Ingeniería Química y Química Inorgánica, Universidad de Cantabria, Avda. Los Castros s/n, 39005 Santander, Cantabria, Spain article info Article history: Received 21 June 2010 Received in revised form 10 September 2010 Accepted 15 September 2010 Keywords: Ultrapurification Hydrogen peroxide Reverse osmosis High-purity chemicals Metallic ion traces abstract The present research is centred upon the application of reverse osmosis to the ultrapurification of aqueous hydrogen peroxide (35%, w/w). Semiconductor Equipment and Materials International (SEMI) organi- zation develops the globally most respected standards to establish the quality requirements for the chemicals used in this sector; one of these standards, SEMI C30 is proposed for hydrogen peroxide. Electronic grade hydrogen peroxide accounts for sub-ppm metallic impurity levels (sub-ppb concentra- tions are required for the most exigent grades), so various elements present as impurities in technical grade hydrogen peroxide exceed the fixed limits. A preliminary experimental study was carried out with a laboratory-scale facility (flat-sheet membrane unit) with 6 different commercial reverse osmo- sis membranes in order to choose the most appropriate one for hydrogen peroxide ultrapurification. BE membrane (manufactured by Woongjin Chemical) was selected for further viability study because of its higher permeate flux (1.95 × 10 -5 m 3 /m 2 s at 40 bar) and metal rejections values (ranging from 0.825 for B to 0.961 for Cu). The Kedem–Katchalsky model resulted as the most representative for characterizing the selected membrane behaviour as it achieved a percentage of overall variation explained upper than 94%. © 2010 Elsevier B.V. All rights reserved. 1. Introduction Hydrogen peroxide is considered a key chemical for the semi- conductor industry. The preparation of semiconductor materials and the manufacture of printed circuit boards employ aqueous hydrogen peroxide solutions for cleaning silicon wafers, removing photoresists or etching copper on printed circuit boards. Most usual cleaning baths for silicon wafer surface cleaning (SC1, SC2 or SPM) include hydrogen peroxide in their formulations [1]. The said baths remove particulate, organic and metallic pollutants from silicon surface, avoiding electric inoperativeness and decreased minority carrier lifetime caused by pollution [2]. In order to avoid contamina- tion because of the bath itself, extremely high levels of purity are required for all the components, so strict control about impurity concentration in these chemicals becomes necessary. Semiconductor Equipment and Materials International (SEMI) organization is the global industry association serving the man- ufacturing supply chains for the microelectronic, display and photovoltaic industries. This organization facilitates the develop- ment of the globally most respected technical standards in this field. Among all the topics regulated, some refer to process chemicals and indicate the requirements to be fulfilled in order to be accepted as ∗ Corresponding author. E-mail address: gareaa@unican.es (A. Garea). electronic chemicals. For the particular case of hydrogen perox- ide, the SEMI C30 document is applicable [3], where six different electronic grades are defined in function of the allowed maximum pollutant concentration, as can be seen in Table 1. Although typically commercialized grades of aqueous hydrogen peroxide solutions have been treated by traditional purification techniques (L-L extraction, adsorption, membrane technologies, distillation...) for lowering impurity levels [4], hydrogen perox- ide for use in electronics demands very low content of pollutants. Hence, ultrapurification processes are needed to achieve electronic grade requirements from standard grade product. While technical viability of hydrogen peroxide ultrapurifica- tion is well solved as commercialization of the different electronic grades demonstrates, scientific papers hinting process fundamen- tals cannot be found. Therefore, patents become the only available bibliographic source. As result of the bibliographical review over the last twenty years, more than 25 patents relative to purification of hydrogen peroxide have been found. According to the noticed references, distillation, adsorption, ion exchange and membranes technologies are the most relevant techniques when electronic grade chemical is desired. Whichever technology is selected, prevention measures to avoid as much as possible contamination from environment and mate- rials are essentials for successful results. The use of cleanroom is a solution for the maintenance of low levels of environmental 1383-5866/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.seppur.2010.09.018