Wafer near-edge geometry can significantly affect the yield of semiconductor device processing.
Knowledge of near-edge geometrical properties can help the producer and consumer determine if the dimensional characteristics of a specimen wafer satisfy given geometrical requirements.
The metric, ZDD, quantifies the near-edge curvature of wafers used in semiconductor device processing.
Consideration should be given to the use of this or other proposed near-edge geometry metrics as a process control tool rather than a material exchange specification.
This Test Method covers calculation of near-edge curvature ZDD (radial double derivative of z [height]).
The metric calculated by this Test Method is based on a height data array; either a single surface (front or back) or thickness.
This Test Method is suitable for polished, epitaxial, SOI, or other layer condition.
The Test Method is applicable to categories of wafers specified in SEMI M1 used in advanced IC manufacturing.
This Test Method does not cover acquisition of the height data array. However, it gives the required characteristics of the height data array.
Referenced SEMI Standards
SEMI M1 — Specification for Polished Single Crystal Silicon Wafers
SEMI M20 — Practice for Establishing a Wafer Coordinate System
SEMI M59 — Terminology for Silicon Technology
SEMI M67 — Test Method for Determining Wafer Near-Edge Geometry from a Measured Thickness Data Array Using the ESFQR, ESFQD and ESBIR Metrics
SEMI M70 — Test Method for Determining Wafer-Near-Edge Geometry Using Partial Wafer Site Flatness
SEMI M77 — Test Method for Determining Wafer Near-Edge Geometry Using Roll-Off Amount, ROA
SEMI MF1530 — Test Method for Measuring Flatness, Thickness, and Total Thickness Variation on Silicon Wafers by Automated Noncontact Scanning
