OCAPS photo resist drying (position 7, 8, 9)

Matrix OCAP: photo resist drying (position 7, 8, 9)

Reject:Dark area of the center, approx. 3 - 5 cm large with raggy windows / holes.

Point to measure:Starting point of air blowing.

(parameter: waiting time air blowing)

Critical measuring point:Starting point of falling dry of the photo resist layer before or after start air blowing (time between t1 and t2).

What to observe:The moment that the photo resist layer changes from a glossy layer into a somewhat frosted / dull layer: the starting point of falling dry of the photo resist layer.

Preferably to observe at the inside of the screen.

Critical parameterThe time between starting air blowing (t1) and first falling dry of the photo resist layer (t2).

This time must be between 0-4 seconds after start air blowing.

In case of too long or too short the time should be adjusted

t1 Start air blowingt1((To measure(

t2 Start falling dry photo resist layer(t2

Start air blowing (t1)t1(

Start falling dry54321012345678 (

of photo resist layer (t2)Too early

(before start air blowing)Good

Too late

ActionDecrease waiting time of air blowing with amount of seconds.No actionIncrease waiting time air blowing by the amount of seconds - 3

Observations:Actions:

1Start falling dry of layer before start air blowing. (Too early)The parameter waiting time of air blowing has to be decreased with amount of seconds between falling dry and air blowing.

2Time between start air blowing and start falling dry is 0 - 4 s. (Good)No actions

3Time between start air blowing and start falling dry longer than 4 - 5 s. (too late) The parameter waiting time of air blowing has to be increased by the amount of seconds between start air blowing and falling dry of the layer minus three.

If the waiting time and the air blowing time together exceeds the process time the air blowing time has to be decreased (in this case most of the time the transport will stop air blowing)

Eric van der Pols 14-04-1998