SEMI HB6 - Test Method for Measurement of Thickness and Shape of Crystalline Sapphire Wafers by Using Optical Probes
This Standard was technically approved by the HB-LED Global Technical Committee. This edition was approved for publication by the global Audits and Reviews Subcommittee on December 4, 2015. Available at www.semiviews.org and www.semi.org in March 2016; originally published June 2015.
Crystalline sapphire wafers (CSW) are used as substrates for manufacturing compound semiconductor devices, in particular high brightness light emitting diodes (HB-LED).
In SEMI HB1 a multitude of requirements is defined for CSW qualified for device production, including geometry and surface characteristics.
Thickness (thickness, thickness variation, local thickness variation) and wafer shape (warp, bow, sori) are important characteristics for depositing layers of III-V compound on CSW during manufacturing HB-LED.
In addition, careful process and quality control of those wafer characteristics during CSW and device manufacturing requires continuous monitoring by the supplier as well as by the user of CSW.
An understanding of the measurements methods used for the qualification of CSW is required to enable agreement on specifications. Such an understanding is provided by standardized test methods for the wafer characteristics.
This Document provides standardized test methods for measuring selected characteristics of CSW, geometry and surface deviations. In addition, this Document defines terms and metrics needed for quantifying the wafer geometry and surface characteristics.
This Test Method covers the noncontact, nondestructive measurement of clean CSW used for manufacturing semiconductor devices.
The diameter and thickness range covered by this Test Method depends on details of the specific set-up used.
The surface condition of the CSW may be as cut, etched or polished.
This Test Method does not cover measurements in the wafer edge profile.
This Test Method may also be applied to wafers of other materials within the constraints of diameter, thickness and surface condition.
Referenced SEMI Standards
SEMI E89 — Guide for Measurement System Analysis (MSA)
SEMI HB1 — Specifications for Sapphire Wafers Intended for Use for Manufacturing High Brightness-Light Emitting Diode Devices
SEMI M1 — Specification for Polished Single Crystal Silicon Wafers
SEMI M20 — Practice for Establishing a Wafer Coordinate System
SEMI MF1569 — Guide for Generation of Consensus Reference Materials for Semiconductor Technology