Anodic Bonding Glass (SD2)

The thermal expansion characteristics of SD2 are matched with those of silicon single crystal. Therefore, anodic bonding with little distortion can be performed over a wide temperature range.

  • Matching thermal expansion characteristics with silicon single crystal
    By carefully selecting the glass composition of aluminosilicate type (SiO2-Al2O3-Na2O type), the thermal expansion was matched with that of silicon single crystal over a wide temperature range.
  • Easy anodic bonding
    The volume resistivity is reduced by adding a small amount of Na. This results in a glass composition that can perform strong bonding even at temperatures of 400 °C or lower.
  • Stable quality
    The variation in the thermal expansion characteristics between production lots is very small and stable.
  • Easy to process
    SD2 can be etched with low concentration hydrofluoric acid aqueous solution, and the etched surface becomes a mirror like surface.

  • Semiconductor pressure sensor substrate
  • Acceleration sensor substrate
  • Nozzle part of inkjet printer
  • Glass for micro-machining bonding
PropertyUnitValueRemarks
Thermal Properties
Coefficient of Thermal Expansionx10-7/°C3230～300°C (thermal expansion meter)
x10-7/°C3330～350°C (thermal expansion meter)
x10-7/°C3430～400°C (thermal expansion meter)
x10-7/°C3530～450°C (thermal expansion meter)
x10-7/°C3630～500°C (thermal expansion meter)
Strain Point°C6701014.5 poise
Transformation (Tg)°C720
Sag Point (Ts)°C785
Mechanical Properties
Specific Gravity2.6
Young’s ModulusGPa87
Modulus of RigidityGPa35
Poisson’s Ratio0.24
Knoop Hardness638
Abrasion Factor44
Chemical Resistance
HN03 Resistancemg/cm20.08*1
H2S04 Resistancemg/cm2<0.01*2
NaOH Resistancemg/cm2<0.01*3
Optical Properties
Refractive Index(Nd)1.531
Abbe-number(νd)59
Electrical Properties
Dielectric Loss(tanδ)0.010　20°C　1MHz
(tanδ)0.019100°C　1MHz
(tanδ)0.049200°C　1MHz
Dielectric Coefficient6　20°C　1MHz
7100°C　1MHz
7200°C　1MHz
Volume Resistivityx1012Ω・m4.1　20°C　DC500V　1 minute
x1012Ω・m0.4100°C　DC500V　1 minute
x1012Ω・m3.8200°C　DC500V　1 minute

*1 Indicates weight reduction in mg/cm2 per unit area when polished glass sample of 43.7 mm diameter (30 cm2 on both sides) and 5 mm in thickness was immersed in well stirred 80 °C 30% HNO3 aqueous solution for 50 hours.

*2 Indicates weight reduction in mg/cm2 per unit area when polished glass sample of 43.7 mm diameter (30 cm2 on both sides) and 5 mm in thickness was immersed in well-stirred 80 °C. H2SO4: HNO3:H2O = 1:1:1 aqueous solution for 50 hours.

*3 Indicates weight reduction in mg/cm2 per unit area when polished glass sample of 43.7 mm diameter (30 cm2 on both sides) and 5 mm in thickness was immersed in well-stirred 50°C. 0.00N NaOH aqueous solution for 15 hours.