1. Clean area for production absolute cleanness – does not exist! cleanness is given by money, that we want (can) spend big influence of used materials – only glass, plastic, stainless-steels, etc. movement of people and goods – undesired, minimized as at is possible (slow moving staff) principle of clean areas: multiple „capsulation“, increase of cleanness step by step through the building indoor area (interior) is cleaner than the outside (exterior)

2. Rules in clean areas Gradual increase of cleanness begins at the reception (take shoes off) Work in boxes – controlled circulation of air-flow (laminar), in the remaining space turbulent Regular cleaning service everywhere (but not so often – it makes a dust ) Minimum movement of people/material (regulated entry) Proper choice of materials (stainless, glass, plastics) No personal things (pencil, papers, mobile, keys, etc-), everything must stay in dress-room Cleanness of media – water, air – big influence on yield Discipline of staff – mainly dress-code

3. Classes of cleanness according FS 209b Class of clean. (simplified) = number of dust particles in a cubic feet (or meter)

4. Classes of cleanness according FS 209b No. Of dust particles in a cubic feet (draft F.S. 209, US) Class of cleanness0,1 um0,2 um0,3 um0,5 um5 um 012345012345 35 350 - 7,5 75 750 - 3 30 300 - 1 10 100 1 000 10 000 100 000 - 7 70 700

5. Air flow – determine cleanness Turbulent advantage: + no accumulation of dust, + easy and cheap to provide. Laminar advantage: highest cleanness, disadvantage: very expensive and difficult to provide.

6. Optical inspection of the cleanness Number of flashes between two (more) mirrors are counted. Each flash stands for a dust particle. Between two mirrors, there is a laser beam.

7. Water – influence on quality and yield H 2 O – used for Si –wafer washing (rinsing) washing of PCB after soldering ultrasonic washing – the most powerful way of rinsing H 2 O – need to have minimum rezistivity (M  required!) distillation of H 2 O – not sufficient, necessary to make: demineralized/deionized water (DIO water) producing of DIO water: Reverse osmotic process – big pressure (MPa) on the water level in front of membrane filter. In front of the filter – accumulation of clean water, behind the filter – rests of ions. Very expensive method.

8. Layout of workplaces and boxes Windows are concentrated at one side, workplaces and boxes on the second side. Filling by chemicals, service, maintenance – only from rear side (so called „grey“ area – lover cleanness)

9. Example of layout – cross section of factory hall

10. Double handover boxes – as in the submarine or space probe. Separation of different atmosphere pressures. Difference of pressures helps to keep pollutions (dust) in current room/space. Materials: stainless steels, plastics (but not all, some of them can generate dust – can crumbing) Manipulation with material – handover windows

11. Air showers – for material/people Handover boxes: equipped by air- shower – material is first blow-off and than can be excluded into clean room.

12. Typical arrangement – boxes at one side, stainless furniture in the middle, windows are opposite.

13. Typical arrangement – vacuum deposition on the left side, stainless furniture in the middle, staff – in the overall clothes.

14. Typical arrangement – windows opposite, minimum of things and tools on the tables.

15. Typical dress-room – personal things are in boxes, overalls hanging on the carriers. Blue doors belong to the „grey“ space.

16. ESD free areas Electrostatic discharges – dangerous for CMOS, TTL and FEL structures/devices Microelectronic circuits can be damaged by energy of the discharge: E ~ ½ CU 2 dont touch! (sensitive)protected (in cover)

17. Immunity of electronic devices to electrostatic discharge Resistance of different groups of devices to voltage breakdown (destructive):

18. Energetic resistance of devices Basic marking of ESD sensitive devices.

19. Influence of human body – most frequent source of ESD Check-in before entering EPA EPA means ESD Protected Areas No grounding! No metallic grounding elements No devices pack into aluminum foil All the connections must be done with high impedance Controlled transfer (draining) of charge

20. Influence of human body – rings, bracelets

21. Connection of metal parts – only through high impedances In EPA areas are possible only distributions systems with isolated phase conductors. Systems TN-C and TN-S are forbidden. From the safety reasons over current protection must be used.

22. ESD roofs in EPAs Special roof for EPA rooms: Older design: stuck (glued) cooper bars on the concrete, double roofs, difficult to build. Today: conductive adhesive (paste) and PVC with powder of graphite or other semiconductor.