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TECHNICAL INFORMATION

Technical
Data

Photomask production processes and technical references for substrates, pellicles, and coatings.

01 / PHOTO MASK PROCESS

Production Process

From exposure to outgoing inspection, the 12-step process shown in cross-section.

  • Production environmentClass in Writer 10 class
  • Temperature22.5 ± 0.1℃
  1. 01

    Writing

    Writing

  2. 02

    Develop

    Development

  3. 03

    Etch

    Etching

  4. 04

    PR strip

    Resist removal

  5. 05

    Metrology (C/D)

    Line width measurement

  6. 06

    Metrology (T/P)

    Position measurement

  7. 07

    Mask clean

    Cleaning

  8. 08

    Defect inspection

    Defect inspection

  9. 09

    Defect repair

    Defect repair

  10. 10

    Final clean

    Final cleaning

  11. 11

    Pellicle mount

    Pellicle mounting

  12. 12

    Audit

    Final audit

  • Glass / Quartz
  • Chrome
  • Resist
  • Defect
  • Pellicle

Process cross-sections are schematic diagrams provided to aid understanding.

02 / FUNDAMENTALS

Fundamentals

Compare Soda lime and Quartz thermal expansion and transmittance. Transmittance uses different wavelengths and thicknesses for each substrate.

Thermal Expansion

Soda lime Quartz -6 -3 0 +3 +6 +4.05μm +0.325μm 22.0 22.5 23.0 Length change (μm) Temperature (°C)
1,000mm board · 22.5°C baseline · room-temperature linear approximation (22.0–23.0°C)
Soda lime
8.1–9.5 × 10−6/K · 8.1–9.5μm per 1°C on 1,000mm
Quartz
6.5 × 10−7/°C (0.65 × 10−6/K) · 0.65μm per 1°C
Length basis
1,000mm at 22.5°C · average over 20–300°C
1,000mm board made at 22.5°C, shown to 3 decimal places. Soda lime uses 8.1 × 10−6/K as a reference curve
Temp. (°C)Soda lime (mm)Quartz (mm)
22.0999.9961000.000
22.51000.0001000.000
23.01000.0041000.000

Transmittance

Quartz 436nm Soda lime 350nm 0 20 40 60 80 100 6.35mm 2 4 6 8 10 Transmittance (T%) Thickness (mm)
Table values only · different wavelengths (Quartz at 436nm, Soda lime at 350nm)
Transmittance by substrate, wavelength, and thickness (T%)
SubstrateWave (nm)2.3mm3.0mm4.8mm6.35mm10mm
Quartz43693.293.3-93.2-
40593.393.3-93.2-
36593.293.1-93.1-
Soda lime35084.7779.2871.11-58.54

The graph connects only values listed in the table. The Quartz line ends at 6.35mm because no 10mm value was supplied. About 93% for Quartz is external transmittance, including surface reflection, and it barely changes with thickness. Quartz at 365nm and 405nm also stays near 93% at the same thicknesses. Soda lime at 350nm is a general grade. UV transmittance varies widely with iron (Fe3+) content, and it falls as thickness increases because of that absorption.

Material properties are manufacturer reference values. CTE is an average over 20–300°C, and the graph is a room-temperature linear approximation from 22.0–23.0°C. Soda lime is 8.1–9.5 × 10−6/K depending on composition. The graph and length table use the low end, 8.1 × 10−6/K, as a reference curve. A 0.5°C Quartz change is about 0.00033mm, so it rounds to 1000.000 at three decimal places.

03 / PELLICLE

Pellicle

Properties of pellicle film types.

Pellicle mounting service

Pellicle film comparison · Supplied reference
PropertyCellulose filmPer-Fluoropolymer film
G-lineI-lineG-lineI-lineKrF
Exposure wavelength rangeSupportedSupportedSupportedSupportedSupported
Transmittance≥99%≥99%≥99%≥99%≥99%
Lifetime (i-line source)200,000 J/cm21,000,000 J/cm2
Equivalent exposure count*Approx. 333,333Approx. 1,666,667

* Values converted from 600 mJ/cm2 per exposure. They are not a guarantee of actual service life.

04 / ANTI-FOULING COATING

Anti-Fouling Coating

Coated versus standard mask properties.

Anti-fouling coating service

Characteristics of coated vs. standard masks
ItemCoated productStandard mask
Thickness≥200Å-
Transmittance89% at 436nm89% at 436nm
Reflectance10±5.0% at 436nm10±5.0% at 436nm
Hardness9H8H
Contact angle≥110°<42°
Water-repellency durabilityChrome ≥60° / Glass ≥100°-

Coating Hardness Test

8H pencil · 1 kg weight · toolmaker's microscope
ItemNormal G/MCoated G/M
Microscope
Standard mask after the 8H pencil test, with dark damage on the pattern
Normal G/M
Coated mask after the 8H pencil test, with no visible damage on the pattern
Coated G/M
ResultChrome and glass damageNo chrome or glass damage

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