SEMI HB7 - Test Method for Measurement of Waviness 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 May 19, 2015. Available at www.semiviews.org and www.semi.org in 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.
Waviness and other surface features are important characteristics for depositing layers of III-V compound on CSW during HB-LED manufacturing.
In addition, careful process and quality control of the wafer waviness during CSW and device manufacturing requires continuous monitoring of waviness 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 a standardized test method for measuring one of the most basic characteristics of CSW, waviness. In addition, this document defines terms and metrics needed for quantifying the waviness of CSW.
This Test Method covers the noncontact, nondestructive measurement of waviness of clean CSW used for manufacturing semiconductor devices.
The thickness range of the CSW to be measured with this Test Method depends on details of the specific set-up used.
The surface condition of the CSW may be as cut or lapped.
This Test Method does not cover any 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