UV: MJB3 (LPN, IEF, SPEC)

UV: MJB3 (LPN, IEF, SPEC)Edit

Description

3 inches photomask aligner

It uses a 200W non-filtered Hg lamp. The dominant wavelength is 405 nm.

single field optical microscope (2 inches field)
suitable for 2 and 3 wafers and small pieces.

Location

Clean Room, room  (LITHOGRAPHY) building D6
Phone:

Person in charge

Christophe Dupuis
room :
phone :  

Christophe Roblin
room :
phone : 

Instructions

Warning : This is a complex and delicate machine.

A training session prior to use it is mandatory .

1) Sign In!!! Check the sign in sheet.

2) The Hg bulb should be started only once per day. Don't turn off the lamp, it will automatically switch off at 9 pm (be carefull if you work late!).

If you are the first user of the day, start Hg lamp by pressing the "start" pushbutton on the power supply located under the table. The lamp needs 30 min to warm up.

3) Turn on vacuum pump - the switch is behind the computer display.

4) Check compressed air, nitrogen and vacuum pressures on manometers.

4) Switch on the mask aligner – main unit.

5) Install mask

• Choose the mask holder according to your mask.
• Load photomask so that chrome side will be facing the wafer. 
• Switch on mask vacuum, install holder but do not tighten knobs.

6) Center the chuck in the X , Y and ? positions using the coarse micrometers prior to load the wafer.

7) Choose the appropriate chuck according to your sample size / shape and the exposure mode you will apply  : see selection table

8) Place your sample (check if the backside is clean). Put it on the sample stage center and slide it to the left so that the chuck is centered below the mask plate. If you are processing small pieces that can't be centered on the chuck, place 2 extra chips of the same thickness forming  together with the first one a large triangle. (see image)

9) Adjust Z stage according to your sample thickness : there are two control bars located on the left-hand side: the contact lever (rotation-bar for raising and lowering the chuck) and the separation lever (slide-bar for alternating between contact and separation). Gently turn the rotation-bar 180 degrees. Never force on this lever. If it seems locked, move the slide-bar into "contact" position (this will enable the contact lever to rotate). While lifting the chuck, you may gauge the separation by looking between the substrate and the mask from the left side of the aligner. Watch also the loosed maskholder.  It should elevate for about 1 mm  when the sample comes in contact to the mask.
If it elevates too high, release contact lever, turn Z stage knob clockwise to lower the stage (make sure it's unlocked), retry to establish contact. If the mask holder doesn't rise at all, release contact lever, turn Z stage knob counterclockwise to upper the stage. Proceed until the mask holder lifts for  approx. 1 mm. Then, release contact lever and thigten the maskholder knobs. The Z stage knob should never be manipulated when the stage is in contact position.

The Z adjustment is done.

10) With the contact lever, slowly raise chuck to  bring your sample in contact with the mask

DO NOT TRY TO ACTION THE CONTACT LEVER WHILE SEPARATION LEVER IN SEPARATION POSITION

11) Turn on the microscope lamp.

12) To move viewing area, the microscope can be positioned with a lever to the left of the mask aligner.
Depress buttons to move in x, y directions. Don't try to move without depressing these buttons. Adjust focus at this
point. Please be careful not to wind the grey wire around  by twisting the lever.

13) alignment :

When you are in contact mode, slide separation lever. This will separate the sample from the mask and allow the alignment.

Use the coarse x, y and theta micro-manipulators to roughly align sample and mask patterns. The micro-manipulators have markers on the fine knobs that show their allowable range. Moving the stage out of these markers will degrade the micro-manipulators. If you reach the limits of the micro-manipulators’ fine range of movement, lower the sample chuck and carefully re-align your sample with coarse knob.

14) Once wafer has been aligned:

• Check if the mercury lamp is hot – When the lamp is hot, UxI should correspond to ~200 watts.
• Bring into contact
• Set exposure time. time is in 1/10 seconds. Integr./time switch on integr. (supposed to adjust time as a function of the lamp brightness)
• Press expose button. The top stage will move forward and shutter will open.

15) After exposure, remove wafer by lowering the chuck and sliding the drawer out.
DO NOT FORCE. If the drawer sticks, center stage with the X and Y
micrometers and the rotation with ? micrometer and then pull the drawer out.

16) After exposing all wafers, loosen knob holding photomask and remove holder.
Turn off the vacuum to mask and remove mask. Replace holder but DO NOT
tighten knobs, the next person will just have to loosen them to put their mask in.

17) Before you turn off the mask aligner ask other users if they want to use it.
Turn off machine in the following order:

a) Turn off power to mask aligner
b) Turn off power to pump (if noone uses the spinner at the same time)
c) DO NOT TURN OFF THE POWER SUPPLY TO THE LAMP (it is done automatically each day at 9:00 pm)

NOTES and FAQs:

  - 3” wafers are the largest size wafer this mask aligner can fully expose. You can use anything smaller than this, even pieces.
  - The microscope's viewing area is only 2" square. Mind this point when you design your masks.
  - If the chuck "sticks" to the mask when you release contact lever, you sample may  require cleaning on its backside (vacuum leak between the chuck and the wafer)

Restarting
Lamp must be cool before restarting … or you risk damaging the lamp.
Therefore wait ~30 minutes after previous use.

How can you tell when the bulb is getting old?
        The power to the lamp is higher than 250W.
        The lamp turns off at any time
What is the voltage to the lamp after it has started?
        ~100 V
What is the pressure in the bulb after it is hot?
        ~1000 PSI or 6.5 MPa !
Why do we use a bulb with such high pressure?
        The high pressure is from a dense mercury vapor. This gives a very high intensity light output.
Why do we use a mercury bulb?
        The spectrum of mercury produces lots of UV light, particularly at 365 nm (i-line), 405 nm (h-line), and 435 nm (g-line).
What should you do if the bulb doesn’t start?
        Press start again.