Photomasks are called in many ways including Reticle and Working mask depends on the application.
NIPPON FILCON define them as follows.
A reticle is a photomask used for steppers and scanners (with step and repeat system) to transfer circuit pattern on wafers. Reticles are available for any types of steppers. NIPPON FILCON supports circuit patterns with various size-reduction ratios are supported to meet stepper lens reduction ratio.
It is often used exposure device like mirror projection aligners which operates exposure without the photomasks touching wafers.
Photomask types and specification
| Photomask types | Light shielding | Mask size | Glass Substrate | Pellicle | Application | Pattern ratio |
|---|---|---|---|---|---|---|
| Reticle | 2 layer chrome (Binary) |
5" or 6" | Quartz | Applicable or not applicable |
Step & repeat exposure equipment (Steppers/scanners) |
5×,4×,2.5×, 2×,1×, |
| Working mask | ~ 9" | Quartz or Soda lime |
One shot exposure equipment (Aligner) |
1× |
Most of all mask sizes are available at NIPPON FILCON.
Below chart shows the standard sizes according to semiconductor standard. Other sizes are also available by cutting the glasses into suitable sizes.
Large size over 10"upto 813mm×813mm is also available. Please see Large photomasks for the details.
| Size | Thickness | 0.06" | 0.09" | 0.12" | 0.15" | 0.18" | 0.20" | 0.25" |
|---|---|---|---|---|---|---|---|---|
| Side length | mm | 1.52 | 2.30 | 3.05 | 3.80 | 4.60 | 5.00 | 6.35 |
| 4" | 101.2 | 4006 | 4009 | --- | --- | --- | --- | --- |
| 5" | 126.6 | 5006 | 5009 | --- | --- | 5018 | --- | --- |
| 6" | 152.0 | --- | 6009 | 6012 | --- | --- | --- | 6025 |
| 7" | 177.4 | --- | --- | 7012 | 7015 | --- | --- | --- |
| 9" | 228.6 | --- | --- | 9012 | --- | --- | 9020 | 9025 |
| UT | --- | 3"x 5" | --- | --- | --- | --- | --- | |
| others | --- | --- | --- | 7.25R | --- | --- | --- |
*Large masks from 10" upto 813mm×813mm are also available.
Line and space thickness as small as 0.5µm is supported for vertical and horizontal straight lines,
Depends on the mask size and design patterns, there are some limitations for the line and space thickness. NIPPON FILCON will let you know the feasibility after checking the design.
| Mask Type | Reticle, Working mask, Master mask |
|---|---|
| Exposure | Laser writing |
| Minimum line thickness | 0.5µm ~ |
| Line thickness accuracy | ±0.05µm ~ |
| Position accuracy | ±0.05µm ~ |
| Defect standard | 0 def. sq. cm/ 0.5µm or bigger |
