SCHOTT Borofloat® 33 / Nexterion® Glass B Flatness and Surface Quality SCHOTT Borofloat® 33 / Nexterion® Glass B Borofloat® 33 is a flat, borosilicate glass Borofloat® 33 is manufactured using the “microfloat” method The production method produces virtually flawless flat glass and a mirror-like surface quality Many Parameters Influence Glass Sheet “Flatness” Surface Flatness is the deviation for a plano surface Warp is the difference between the maximum and minimum deviations of the median surface relative to the backside reference plane. Warp is like the wavy deformation seen in potato chips. Bow is the measure of how concave or convex the deformation of the median surface of the glass sheet at the center point, independent of any thickness variations. The easy way to visualize Bow is if you think of a bowl turned either upside down or right side up on a flat surface (convex or concave). Total Thickness Variation (TTV) represents the difference between the minimum and maximum thickness measured on the sheet of glass. Thickness Tolerance (inter-slide) The production of large flat sheets of glass yields variances in thickness. Thickness will vary depending on sheet size and where on the sheet the measurement is made. In order to accommodate this fact SCHOTT uses a nominal tolerance value Thickness deviation (intra-slide) This is the thickness differences between slides Surface Roughness Smoothness: RA (average roughness) or RMS (root mean squared) is a measure of the texture of a surface. Bow and Warp Total Thickness Variation (TTV) “Flatness” of Nexterion® Glass B Slides SCHOTT Nexterion® defines “flatness” as the accumulated overall possible thickness deviation This includes warp, intra-slide thickness deviation, and interslide thickness tolerance convex side up Warp Thickness deviation intra-slide S-shape a Thickness tolerance inter-slide b concave side up Warp P Nexterion® slides have a maximum total “flatness” deviation of ≤ 25 µm for these three factors combined Measurement of individual Glass B Slide Flatness using Interferrometry ZYGO's VeriFire™ XP/D Laser Fizeau mechanical phase-shifting interferometer Flatness of Nexterion® Glass B Slides The typical flatness across a single 75.6 x 25 mm slide is ≤ 5 µm Surface MicroRoughness of Glass B Slides Measured using Digital instrument nanoScope Atomic Force Microscope (AFM) Surface MicroRoughness of Glass B Slides Typical MicroRoughness Ra < 3 nm This data represents typical average values and is for reference only. Thank you