2-4.Wafer Surface Orientation
Denotes the orientation of the surface of a wafer with respect to a crystallographic plane within the lattice structure.
In wafers cut intentionally “off orientation”, the direction of cut is parallel to the primary at, away from the secondary at.
Measured with x-ray goniometer on a sample of one wafer per ingot in the center of the wafer.
3-9. Comet Tails Comet tails have a discrete head and trailing tail. These features are aligned parallel to the major at. Usually, all comet tails tend to be of the same length. Count once per occurrence. Two comet tails within 200 microns count as [...]
2-23.Micropipe density A micropipe, also referred to as “micropore”, “microtube”, “capillary defect “or “pinhole defect”, is a crystallographic defect in a single crystal substrate.It is a important parameter to manufacturers of silicon carbide (SiC) substrates which are used in a variety of industries such as [...]
3-1. Large Point Defects Defects which exhibit a clear shape to the unassisted eye and are > 50 microns across. These features include spikes, adherent particles, chips and craters. Large point defects less than 3 mm apart count as one defect.
2-12.Edge Exclusion The outer annulus of the wafer is designated as wafer handling area and is excluded from surface nish criteria (such as scratches, pits, haze, contamination, craters,dimples, grooves, mounds, orange peel and saw marks). This annulus is 2 mm for 76.2 mm substrates, and [...]
2-24.Wafer Orientation Wafers are grown from crystal having a regular crystal structure, with silicon having a diamond cubic structure with a lattice spacing of 5.430710 Å (0.5430710 nm).When cut into wafers, the surface is aligned in one of several relative directions known as crystal orientations. [...]
1-2.Stacking Sequence If we are going to make a laminated structure, we must know the thickness of each ply and the angle of each ply traditionally in degrees defined from the top layer down.
