Dust Level Control in Phototooling Basics

Transcription

1 Dust Level Control in Phototooling Basics Eric Janssens January 2002 EJA January

2 What is dust? Any material particles that may have a negative effect on their environment EJA January

3 Sources of dust Natural dust Cosmic dust from outer space Eruption of volcano s Sand, stone... due to erosion by wind and water Seeds, pollen Humans Man generated dust Exhaust by industry and traffic Generated by any friction Human body tissue: hair, skin particle, sweat,. EJA January

4 Dust generated by the human body Calling generates 20,000 particles Coughing generates 600,000 particles Sneezing generates 1,200,000 particles A man looses 1 hair every 15 minutes A man looses 15 grams of skin tissue every day EJA January

5 Dust generated by peoples action Writing on paper Folding paper Rubbing on a painted surface Rubbing metal on metal Putting on a screw 30µm particles 60µm particles 90µm particles 100µm particles 100µm particles.. By moving man make dust particles air born EJA January

6 Dust particles - Size distribution Air born dust particles range in size from 0 to +/- 50 µm There are many small particles and fewer larger ones Remark: dust particles may conglomerate EJA January

7 Dust particles - Size distribution EJA January

8 Definition Clean Room Class Clean room class x means: one cubic feet of air contains x particles of 0,5 µm or smaller EJA January

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10 The importance of clean room conditions As long as dust particles are relative small compared to the lines and spaces they don t cause much trouble Stricter demands for PCB frication Ever decreasing line and space widths Stricter tolerances for lines and spaces and pads More layers Higher yield Today the size of an average dust particles is ¼ to ½ of an average L/S Today dust particles cause more defects and the defects are more expensive EJA January

11 Dust particles in PCB production Dust particles jeopardise image formation: Phototool generation Dust on the film while plotting Dust in the light path while plotting Dust on the plotter drum (fly off, out focus) Dust on the film while processing Primary imaging Secondary imaging Dust particles scratch phototools and resist EJA January

12 Dust measurement Measuring/counting tools Particle size Measuring device µm Filter > 20 µm Petri dish EJA January

13 Petri dish EJA January

14 Pert dish EJA January

15 Pert dish EJA January

16 Dust measurement Measuring/counting tools Remark Particle size Measuring device µm Filter > 20 µm Petri dish µm Particle counters with light* µm Particle counter with laser light* * does not measure the heavier dust particles The naked human eye can see: 50 µm particles under normal conditions 25 µm particles under ideal conditions EJA January

17 Dust measurement: take care We are fighting an invisible enemy EJA January

18 PCB production anno 2000 To remain competitive in the PCB industry production is to be done in clean room conditions where the dust level is well controlled EJA January

19 Clean room: the compromise A clean room has to be build correctly and used correctly Find a compromise Quality of the installation versus installation cost Discipline applied versus comfort EJA January

20 Clean room: how to organise No paper or card board (paper is compressed dust) Limit access of people Limit access of materials Avoid transportation from one compartment to another (install hatch) No cutting or punching of film in the clean room No knifes,no scissors, nail files, no pencils No posters, no photos, no radio Use clean room certified tools and equipment discipline discipline discipline discipline discipline discipline discipline EJA January

21 Clean room: how to act No paper or card board (paper is compressed dust) Clean feet Dress correctly (overall, hair cap, over shoes, gloves) Never ever enter in out side clothing, not even for just a second Never ever leave the clean room in clean room clothing No brief cases, no handbags No food, no drinks, no smoking Move slowly and as little as possible Keep films in vertical position, use (humidity tide) envelopes Clean the film as often as needed discipline discipline discipline discipline discipline discipline discipline EJA January

22 Clean room: maintain dust level Golden rule Prevent dust generation (people, production process, environment) Prevent dust from entering the clean room Remove dust EJA January

23 Clean room: maintain dust level Implement cleaning programme per batch, shift, day, week, month what to clean, how to clean Remark: after cleaning the dust level is higher as before vacuum cleaner out of the clean room Replace mats Replace filters Wash clean room clothing in special washing machine discipline discipline discipline discipline discipline discipline discipline EJA January

24 Clean room: SPC programme Dust level at all relevant locations Cleaning Pressure over the filters Air flows. discipline discipline discipline discipline discipline discipline discipline EJA January

25 The ideal phototool l Shoeshine Hatch Changing room Overalls Haircap Glovers Over shoes + Hatch Film stock Lock Dust retaining mat ++ Package Check Retouch Lel Measure Plotter Processor Copy onto diazo Laminate Climitise film ++++ EJA January Chemistry supply

26 Dust level control at Agfa Agfa s commitment Production in class 1,000 Cutting and packaging in class 5,000 Special PCB packaging Film safe EJA January

27 Dust level control at Agfa EJA January

28 Dust level control at Agfa EJA January

29 Dust level control at Agfa EJA January

30 Dust level control at Agfa EJA January

31 Dust level control at Agfa EJA January

32 PCB packaging EJA January

33 Film safe 790 mm x 680 mm: FROJN 1179 mm x 870 mm: FROFG 1690 mm x 1480 mm: FPMM3 EJA January

34 Conclusion Working in clean room conditions is producing with well-focused discipline in a well-monitored environment in order to control defects EJA January

35 Conclusion Dust level control in the PCB industry is a question of common sense and discipline! but it makes the difference between making or loosing money EJA January