MA6 Back-side Alignment

6.3.1 Adjust Location, Focus and Illumination

1. Back-side Alignment (BSA) microscopes will be active when clicking the "Mask Holder NOT Clamped" button.

• TSA microscopes do not move down.

2. The mask image will be shown on the PC screen through the windows of the wafer chuck.

3. Find the alignment marks using the following knobs for the BSA microscopes.

4. Adjust focus and illumination on the mask using the following knobs and indicators.

• Independent X- and Y-direction shift and focusing knobs for the right and left BSA microscopes.

• Focus and illumination indicators in the window.

5. Click the "Grab" button to capture the image of mask targets.

6. The following message appears.

6.3.2 Load Sample

1. Load the 4" wafer chuck and wafer, as shown in Non-Alignment.

• Make sure that the structure on the wafer is on the back side.

2. Click the "Next" button to turn on wafer vacuum.

3. Move the transport with the sample slide in.

4. Click the "Next" button.

5. The following window appears.

Note:

• If this window keeps being shown, the stage position is deviated too much from the position appropriate for the WEC contact, as a result of the alignment.
• If you click the "Close" button, then the WEC contact is stopped, resulting in the bad contact.
• In the alignment procedure, the vacuum contact should avoid this issue.

‎

6.3.3 Alignment

1. The following message appears.

2. Find and focus on the image of the alignment marks of the wafer.

3. Make an alignment between the wafer and mask image captured, using the manipulators.

• Manipulators

• The alignment (AL) gap is automatically set to be 25 μm, according to the recipe set up.
• If you are not comfortable with the AL gap, then move the Z-axis using the "Move Z-Axis by Steps" box on the right side of the window.
• You can check displacement upon the contact between the mask and sample, using the "Move Z-Axis box".

4. In the manual BSA alignment process, ignore the following messages in the window:

• Press [AL Check] to move to exposure position

5. Go to the Exposure section below.