Aarhus University Seal / Aarhus Universitets segl



APV Arias Wet Bench designed for Aarhus

Document Responsible: Pia Bomholt Jensen        

Date: 21/1 2014

1)    Purpose/Formål

The purpose of this APV instruction is to ensure that employees at iNANO are aware of the potential dangers that exist when working with the Arias Wet Bench located inside the cleanroom facility. The aim of this APV instruction is also to prevent personal injury to maintenance personnel of the Arias Wet Bench. All users who work on the instrument should be aware of the potential hazards listed


2)    The Instrument/Instrumentet

The wet bench is an instrument specially designed and constructed to serve the photoresist processing needs of iNANO and fits into the existing cleanroom infrastructure. Integrated into the wet bench are smaller instruments for processing resists. Integration allow optimal space usage, high safety, and efficient resist processing.  Because the diversity of photoresist needs at iNANO the instrument is equipped with manual resist spin coaters and hot plates for maximal flexibility compared to automated systems that only handle a few resists. To develop different resists of high chemical dissimilarity, the wet benches are equipped with manual development bath for maximal flexibility. The smaller instruments that are integrated into the bench are one HMDS oven (a dedicated APV have been made) for superior adhesion  of resists to sample, 2 resist spinners for resist coating of wafers, 2 hot plates for driving out resist solvents after spin coating, one convection oven for resist baking or dehydration, one quick dump bath for alkaline developers, one quick dump DI water bath with integrated water conductivity sensor for rinsing wafers after development, one section dedicated to lift-off process with temperature controlled ultra-sonication bath, acetone bath, isopropanol bath and quick dump DI water bath. Chemicals are stored in ventilated cabinets under the working surface. While highly functionally integrated for resist processing, the wet bench is also designed to maintain the laminar flow in the working area and through out the yellow room. Because most resists and chemicals for development are relatively harmless, we adapted an open wet bench design, which has the advantage of superior laminar flow and easy access to the many integrated components. However, this open design does not protect the users from splashes. Therefore for safety reasons only harmless organic chemicals and weak alkaline developer solutions with low toxicity are allowed. In other words, the wet bench must not be used as a fume hood!!  


3)    Hazardous Conditions/Risiko

Hot surfaces can cause burns. Users can be exposed to hazardous chemical fumes if chemicals are not handled according to equipment training instructions by super-users. There is a risk of fire if chemicals are not handled safely. There is a risk of chemical explosions.


4)    Protective Clothing/Beskyttelsesdragt

A cleanroom suit, protective eye ware, gloves must be worn when working at the wet bench. The user must clean the resist spinners with napkins soaked in acetone and isopropanol. The users are required to use an additional layer of acetone resistant gloves for this purpose.


5)    Identification/Identifikation

The wet bench is designed for resist processing and due to the open design, only chemicals with low reactivity, toxicity, corrosiveness are allowed. Strongly oxidizing and explosive chemicals are strictly forbidden. Still, caution and care must be taken when working with chemicals. There are many toxic and non-toxic chemicals stored in the ventilated space in the wet bench. Please consult super-user and read MSDS. 


6)    Maintenance/Vedligeholdelse

Bath with acetone and isopropanol are drained into stainless steel waste containers in the technical room. Sensors will inform the user that the waste containers are full.  


7)    Additional Safety Notes/Ekstra sikkerhed

Because of risk of explosion of chemical vapor and ignition by the instrument electronics, the instrument electronics are constantly purged with a flow of nitrogen to remove vapor from organic solvents, and instrument shuts down if integrated sensors detect low nitrogen low. Sensors in the ventilated chemical storage space detects major chemical spills and warns the user. 


8) Electrical Safety/ El sikkerhed

The instrument is powered by 3 phase 400V electricity. The instrument is CE marked. However, the electrical safety can be compromised and deadly to the user if the instrument is repaired by unauthorized personnel.