GB/T 31352-2014Test methods for warp of sapphire substrates (English PDF)

3.1 Warp

Free and holding the wafer difference between the maximum and the minimum distance between the planes and the reference plane planes.

3.2 The median plane datum plane

Designated by the wafer is less than the nominal diameter of the plane three equidistant points on the circumference of the diameter of the decision.

4.1 Contact test

The sapphire substrate sheet is placed on the three fulcrum reference ring 3 forms a fulcrum reference plane, the use of low pressure along the displacement indicator

Sapphire substrate sheet measuring predetermined path distance from the reference plane, the record in pairs displacement indicator readings and find the difference, for a range of

Paired difference between the maximum and minimum values whichever is the difference divided by 2, which means that the value obtained warpage of the substrate sheet.

4.2 Non-contact test

The sapphire substrate sheet is placed on the three fulcrum reference ring 3 forms a fulcrum reference plane, the use of non-contact displacement sensor

Along a predetermined path sapphire substrate sheet measuring distance from the reference plane, the record in pairs displacement indicator readings and find the difference, for a series of

Tabulated values for the difference, whichever is the difference between maximum and minimum values divided by 2, which means that the value obtained warpage of the substrate sheet.

4.3 white light interferometric test

Sapphire laser irradiation surface of the substrate sheet, the light reflected through the superposition of interference, the interference pattern recorded by the optical imaging system, the level of the beginning of shape

Measurement appearance; in the Z-axis direction of the objective lens continues to move slightly, in each position thereof, the optical imaging system to collect image photographing, shaped […]