User Manual - The University of Texas at Dallas
Contents
1. run plenty of DI water at the same time to dilute it This is a serious issue because strong bases and acids can react violently in the drain lines When you are finished clean up your work area and return all the tools you have been using to their proper place especially papers and rags DOCUMENT TITLE Base Hood Operations 11 1 2005 Roger Robbins Page 8 of 12 Appendix A Air Flow measurements Airflow measurements in linear feet per minute were taken with the main exhaust damper at full open The slit damper in the back wall of the hood was also set at full open Readings were taken at the center of the front sash opening and at the center of each of the slit exhaust openings on the back wall of the hood The airflow measurements are shown in Table A1 Slit 1 Slit 2 Airflow at Center of Hood Face Opening Figure A1 Face opening of Base Hood showing location of Air Flow measurements Table A1 Air Flow Measurements Flow Location ft min 1190 _Upper Slit Lower Slit 1275 Main Exhaust Damper full open Slit valves full open DOCUMENT TITLE Base Hood Operations 11 1 2005 Roger Robbins Page 9 of 12 Appendix B Maintenance Details This appendix contains a collection of photos showing the hood infrastructure details for maintenance reference SINK TIME ENTER SINK HOTPLATE HR MIN SEC PTIMER OFF TIMER OFF at po 0 35 4 22 08 BEAKER TEMP 20 5 C A Figure B2 Sink Timer Screen2. under the removable panel In addition to the hotplate itself there is a separate thermocouple temperature probe available to measure the temperature of the medium that you are trying to heat This probe is located in its holding fixture in the right rear corner of the hood The temperature is read on the control panel by pushing the Process button DI Water Sink The DI water sink is connected to the acid drain line and can accept waste base solutions with plenty of water dilution The DI water faucet is a recirculating loop so that the water does not stagnate and grow microorganisms which contaminate the water with particles and organic material Figure 6 DI water sink and recirculating DI water faucet DOCUMENT TITLE Base Hood Operations 11 1 2005 Roger Robbins Page 7 of 12 Rules of Operation Now that the features of the hood have been described we will put forth a few operating rules Rules When approaching the hood to start work please notice the conditions in the hood and note any situational dangers Either correct them or notify Clean Room Staff Fill out the required Chemical use form Wear appropriate personal protective equipment o Safety glasses o Appropriate gloves o Chemical apron if necessary Only one operation at a time is allowed Never place a chemical container on the floor Always turn off the hotplate when your job is complete You can slowly dump waste base solution into the sink but
3. Base Hood Operations Roger Robbins 11 1 2005 The University of Texas at Dallas ERIK JONSSON SCHOOL OF ENGINEERING DOCUMENT TITLE Base Hood Operations 11 1 2005 Roger Robbins Page 1 of 12 Base Hood Operations Roger Robbins 11 1 2005 Table of Contents Base no0d OSO irrita 3 INTOAUCH Misa dados 3 DescuplOlia nana liada 3 CAR Deals asista iii iacio n 4 COO AN ere ere Mer eo ene IE ne eNO ee ie tebe See Seri renee ee eer ee 4 A e A 4 EX aro 5 Maene St USO 6 EMODE O AAA NA 6 AU ENANA td 6 Hood Controller KeypadW DISplay omccoconccoccnnnoconnnonanononannnonannnononononenonancnnns 6 o aan de pase ET meat OT E E ERE 7 OM LCI oN CRM eae eaten ig Kea aa en es apenas ere eccee mee orcsm man anc teases 7 Rules OF OB Sr ANON es ii beat 8 PADDCNIOIX AY ETE N E O 9 POO CIICIN D rere 10 Maintenance Details 0 0 ccc ccccccccesceceseeeeseeseueuseueusaueuuaueuaueuaueaveusaueuuaueuuans 10 DOCUMENT TITLE Base Hood Operations 11 1 2005 Roger Robbins Page 2 of 12 Base Hood Operations Roger Robbins 11 1 2005 CAMyDocuments Teaching RogerPapers BaseHoodOps doc Introduction This document describes the Clean Room s 4 foot base hood from leatherwood Plastics Inc Lewisville Texas This hood is intended to be used with bases only especially no solvents It is a plastic hood with a DI water sink and a hotplate built into the working surface Normally it is used for optical resist development It is small and can suppo
4. HOTPLATE TIME ENTER HR MIN SEC NO 22 06 SHO ALARMS pa 4 5 Figure B3 Hotplate Timer Screen Figure B4 Alarm Screen LEATHERWOOD PLASTICS PHOTORESIST BENCH UTD JOB 198 Y Figure B5 About screen Hood Mfg ID DOCUMENT TITLE Base Hood Operations 11 1 2005 Roger Robbins Page 10 of 12 TE SA A z Ss ta E S A Figure B6 This is the sump where the water drains from the sink Do not throw resist in this sink Resist dissolved in developer is ok NO SOLVENTS Solvents will dissolve the hood Figure B7 Access panel to change the Hood light DOCUMENT TITLE Base Hood Operations 11 1 2005 Roger Robbins Page 11 of 12
5. r to set the time on the two timers and see the temperature on the thermocouple probe The time is set by pressing the star key under either the sink timer or the hotplate timer and then either entering the times from the numeric keypad or pressing the up or down arrows in the oval keypad The alarm key brings up the alarm screen which displays the current and last few alarm messages Pres the Process key to see the temperature of the thermocouple temperature probe Figure 4 Controller keypad display and timer start stop keypads under the work surface on the front DOCUMENT TITLE Base Hood Operations 11 1 2005 Roger Robbins Page 6 of 12 Hotplate The hotplate shown in Figure 5 is a simple manual stirring hotplate with local controls located under the removable panel just in front of the hotplate There is a protective skirt around the hotplate heating surface to protect the hotplate from accidental spills into the sunken hotplate recess just below the hotplate heating surface This protects the hotplate itself from internal damage from chemical spills However in the event of an accidental spill onto the cool hotplate heating surface quickly wipe off the chemical re wipe with a DI water wetted wipe cloth and finally dry it off The local control knobs set the temperature and control the stirring magnet speed Figure 5 Stirring explosion proof manual hotplate showing protective skirt and controls
6. rt only one operation at a time Description The base hood is constructed of a chemical and fire resistant white PVCC plastic with a 3 by 2 5 foot perforated work surface including a DI water sink with gooseneck faucet and an imbedded manual hotplate There is a thermocouple temperature probe for measuring the temperature of your working medium on the hotplate There is an ergonomic sloping control panel on the left side that houses control functions for the hood The lighting is provided as filtered yellow light that will not expose optical resists The hood is exhausted by a 10 inch plastic exhaust line that leads to a chemical scrubber on the roof of the building The exhaust pressure is monitored by a photohelic pressure gauge which will set off the alarm and shut down the hood if the exhaust pressure is lost The sink drain leads straight to the chemical drain system acid drain line There is a Nitrogen blow off gun on a coiled line embedded in the work surface along with a DI water spray gun also on a coiled line These major features are shown in Figure 1 DOCUMENT TITLE Base Hood Operations 11 1 2005 Roger Robbins Page 3 of 12 Thermocouple Temperature Sensor Hotplate aa DI Water sink and faucet DI Water Gun Nitrogen Gun Exhaust ye Pressure Process Timers Gauge Figure 1 Base hood 4 ft showing major hood features Feature Details Control Panel The control panel is shown in Figure 2 and support
7. s the microprocessor keypad display the Emergency Off button EMO and the DI water resistivity readout along with the machine start stop buttons and a loss of exhaust light DI Water The hood has a recirculating de ionized water plumbing system to prevent stagnant water from growing microorganisms and contaminating the purity of the water Ther is a monitor readout of this condition at the top of the control panel that displays the resistivity of the water in meg ohms The nominal value of good DI water is 18 1 meg ohms or better If you notice that the value has slipped into the 17 meg ohm level or lower please notify the clean room staff and if this would impact your work discontinue using the water DOCUMENT TITLE Base Hood Operations 11 1 2005 Roger Robbins Page 4 of 12 DI Water Condition Meter Loss of Exhaust Indicator Light Hood Start Button Audio Enunciator Emergency Off Button Alarm Silence Button Hood Power Off Button Information Keypad Display Figure 2 Hood Control Panel Figure 3 Photohelic Exhaust pressure gauge left and alarm horn right Exhaust The photohelic pressure gauge Figure 3 measures the exhaust pressure in the exhaust line above the hood and if the pressure falls out of the acceptable range it will trigger the alarm horn Figure 3 to complain very loudly and the red alarm light on the control panel to light up Figure 2 If this happens quickly bring your work to a safe concl
8. usion and discontinue the use of the hood Also immediately notify clean room staff There may be a general loss of exhaust requiring clean room evacuation Follow staff direction DOCUMENT TITLE Base Hood Operations 11 1 2005 Roger Robbins Page 5 of 12 Machine Start Stop The Green HOOD START button on the control panel turns on the electricity to the hood functions The Red HOOD STOP button turns off most of the electricity to the hood Fire suppression power is left on and can only be turned off by the main disconnect The hood is generally left ON all the time This control is generally used when service is required EMO Button The Emergency Off Button is used if the hood is having an electrical problem that portends of immediate emergency If there is smoke coming from the insides or the hotplate is seriously overheating please don t hesitate to use this button If you have had to push the EMO button please notify Clean Room Staff immediately Audio Enunciator The audio enunciator is a piezoelectric beeper that announces either a non emergency fault or the completion of a timed event There is a convenient yellow alarm silencer button which you can use to cause immediate secession of the annoying beeps However please make sure that the cause of this alarm is corrected before leaving the hood Hood Controller Keypad Display This is a simple controller with very few functions It mainly allows the use
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