The synthetic fused silica glass AQ series is a high-purity, high-quality functional material based on AGCʼs abundant experience accumulated over its long history of technological R&D in fine glasses, fine chemicals, and fine ceramics.


  • Lens material for Semiconductor lithography system
  • Lens material for FPD lithography equipment
  • Photo mask substrate
  • Other optical materials
  • Glass wafer

AProduction method and Features of AQ series

AGC’s Synthetic Fused Silica AQ series is manufactured by the VAD method. The VAD method can reduce Si-OH content, providing customers with synthetic fused silica with the following features.


  • High transmittance for deep ultraviolet rays with frequencies < 200 nm ranging from the i-ray to KrF, ArF, or Xe excimer lamps, and even for near infrared rays *1
  • Excellent Compaction/Rarefaction and Polarization Induced Birefringence(PIB) characteristics*2
  • Resistant to heat processing around 1000°C*3
  • Excellent durability against high-energy laser beams
  • Thermal expansion as low as 1/10 that of conventional glass
  • High uniformity
  • Very high purity, very low metal impurity content
  • Low OH group content
  • Outstanding chemical resistance
  • Low dielectric loss
  • *DUV-absorption due to electron transition and IR-absorption caused by Si-OH vibration are both reduced.
  • *No rarefaction can be seen in silica glass having low SiOH content such as AGC silica glass. In addition, some ArF excimer laser exposure tests indicate low SiOH containing silica glass has good compaction and PIB characteristics. AGC has installed excimer laser exposure test lines to estimate long-term durability of silica glass. AGC has been diligently researching and developing based on a wealth of the exposure results for a long time.
  • *Decrease in SiOH content makes the Si-O-Si binding network rigid and viscosity high, and consequently makes the heat resistance of silica glass high.

Typical Characteristics

Chemical constitution SiO2 wt(%) 100
Thermal properties CTE ppm/K (50 to 200℃) 0.6
Softening Point 1600
Annealing Point 1120
Strain Point 1060
Optical properties Refractive Index nD 1.46
Chemical properties Acid Resistance mg/cm2 0.000
Alkali Resi mg/cm2 0.032
Mechanical properties Density g/cm3 2.20
Young’s Modulus GPa 74
Knoop Microhardness kg/mm2 540
Electrical properties Bulk Resistivity log(Ω・cm) at 200℃ 12.5
Dielectric Constant at 1MH,R.T. 4.0
  • Data is for reference only.

Transmission Range

Transmittance in Deep Ultraviolet Range

  • Data is for reference only.

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Product catalog
Designation Features and principal applications
AQ The standard grade of AGCʼs synthetic fused silica glass
Application example: Photomask Substrate (~KrF), Glass Wafer, Illumination Optics for i-line (365nm
Life science, UV-LED
AQ3 AQ enhanced in uniformity of refractive index
Application example: Projection Optics for i-line (365nm)
QJ AEnhanced purity AQ, with guaranteed low metallic impurity content
Application example: Glass wafer for High-temperature and High-purity Process, HTPS, Life science applications
AQ2 High transmittance in vacuum ultraviolet and near infrared
Application example: Optical material for Xe excimer lamp (172nm)
AQT High resistance against deep ultraviolet excimer laser beams along with highly uniform refractive index
Application example: Projection Optics for ArF excimer laser (193nm)
AQR High resistance against deep ultraviolet excimer laser beams
Application example: Illumination Optics for ArF excimer laser (193nm)
QC‐i High transmittance for deep ultraviolet excimer laser beams and low birefringence
Application example: Photomask Substrate for ArF immersion system
AQ4 High resistance and high transmittance in a range from UV to DUV
Application example: Window material for Low-k wiring device, etc