Lightwave Logic Inc (LWLG)

[XenaLives]

But apparently "final yield" can be affected my many other factors...

Measuring yield
The final die yield is the compounded yield of all the independent steps that are required to produce a functional die. Those include:

Wafer Yield (YW) - fraction of wafers that are not scrapped
Die Yield or wafer sort yield (YD) - fraction of dies that are not scrapped
Assembly Yield (YA) - fraction of chips that are not scrapped during the packaging stage
Burn-in Yield (YB) - fraction of chips that pass burn-in
The overall yield is therefore Y = YW · YD · YA · YB

Yield loss
Yield loss refers to the source that affects the final yield. Those usually fall into two categories:

Parametric Yield Loss - Dies that function but not within the desired specifications
Catastrophic Yield Loss - Dies that do not function due to a defect
During a new process technology bring-up, yield loss can be very high (< 40% yield). The process of identifying yield losses, quantifying them, and improving them is referred to as yield learning.

https://en.wikichip.org/wiki/yield#:~:text=Measuring%20yield%5Bedit%5D,dies%20that%20are%20not%20scrapped