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MJB4 Staff Page (Restricted)

 
iLab Name: C - MJB4
iLab Kiosk: BRK Lithography Core
FIC: Shared
Owner: Joon Park
Location: Cleanroom - N Bay
Maximum Wafer Size: 4"/100 mm

Overview

General Description

The Suss MJB4 is a contact mask aligner for exposing pieces up to 100 mm wafers with 3, 4, and 5 inch photomasks.

Specifications

• Light source: 
  • 350 W Mercury Short-arc lamp, Micro Lens (MO) optics for sharper edges.
  • Output wavelengths: 350-450 nm, covering the g-line (436 nm), h-line (405 nm), and i-line (365 nm)
  • Exposure uniformity: ±2.5% over 100 mm round.

• Output intensity: 

  CP	CI1	CI2
  275W	25 mW/cm2 at 365 nm (i-line)	60 mW/cm2 at 405 nm (h-line)

• Maximum resolution, under optimum conditions with 1 μm thick resist:
  • Soft contact: 2.0 μm
  • Hard contact: 1.0 μm
  • Vacuum contact: <0.8 μm
• Alignment accuracy, under optimal conditions:
  • Top Side Alignment: 1 μm, <0.5 μm with "SUSS recommended wafer targets"
  • Infrared Alignment (not equipped, would require purchase of BSA options): 2 μm
• Travel:
  • Alignment stage travel:
    • X & Y: ±5 mm, resolution of 0.1 μm
    • Theta: ±5°, resolution of 4x10^-5°
  • Topside Microscope Travel:
    • X: ±40 mm
    • Y: +25 mm to -55 mm
    • Theta: None with single field,  ±4° with optional splitfield microscope (would need to be purchased)
• Usable masks and substrate:
  • Substrate Sizes: 5 x 5 mm up to 100 mm wafer
  • Substrate thickness: Up to 4 mm
  • Mask size: 2" x 2" up to 5" x 5"
    
    

Sample Requirements and Preparation

Samples should be cleaned and prepared with further processing steps in mind, as well as conditions that enable good adhesion between the substrate and photoresist.

For the aligner itself, samples must be free of resist on the substrate backside. If any resist or residue is present, it should be removed with the following process:

1. Put on a clean, new pair of solvent gloves.
2. In a solvent hood (with appropriate PPE), squirt some acetone on either a cleanroom wipe, a cleanroom swab, or a polyester wipe.
3. Hold the sample firmly with tweezers, or if necessary, with clean, double gloved hands. Note that holding with hands is only recommended if the gloved hand has touched NOTHING since being put on.
4. Carefully wipe the wafer backside with the wipe/swab, making sure not to touch the substrate front side. Acetone can wick into resist, and so should only areas of resist to be removed.
5. Repeat as necessary to remove any residue.

Proper Alignment of Wafer Pieces

The MJB4 uses a self leveling stage to automatically planarize the substrate chuck against the photomask when contact mode is engaged. This works well for wafers, but this mechanism must be considered when using small substrate pieces. When exposing on a single piece, be sure to place it directly in the center of the chuck. To further assist in proper planarization, place 3 spare substrate pieces evenly separated towards the edges of the chuck.

Standard Operating Procedure

Written SOP

Training / SOP Video

Questions & Troubleshooting

Why am I having so much trouble aligning for a two step lithography?

When using small samples, be sure to place them in the center of the chuck. If this is not possible, placing 3 "helper" pieces may level the sample. See Proper Alignment of Wafer Pieces for more info.

How do I start the lamp power supply?

BNC standard procedure is to leave the lamp power supply "on" at all times. In the rare event that a previous user has turned off the lamp power supply, follow the instructions below to restart it:

1. Activate power by pressing the ON key.
2. Wait for the display to show "READY".
3. Ensure the "350W Hg" LED is lit under LAMP TYPE. If any other lamp type is lit, turn the power off, contact BNC staff, and leave a note on the tool indicating it is down. Starting with the incorrect lamp type selected may cause the lamp to explode.
4. After verifying the display shows "READY" and the "350 W Hg" Lamp Type LED is lit, press the CP key.
5. The display will show "WAIT", and then "START". Once start is shown, press the START button.
6. The lamp ignition sequence will commence. It will display "IGNITION", then "LAMP COLD", and the "LAMP LIFE/POWER" LED in the FAILURE group may blink until the lamp reaches operating conditions.
7. Once the warm-up sequence is complete, the LAMP POWER display will show the actual lamp power.
8. Press the CH1 or CH2 button depending on the calibration required.

Process Library

References

Suss

MJB4 User Manual - Condensed (Internal Resource)

MO Exposure Optics (Internal Resource)

MJB4 Brochure (Internal Resource)