Metal contamination in a semiconductor manufacturing environment can greatly reduce wafer yield or create long term product reliability issues. Vapor Phase Decomposition Inductively Coupled Plasma Mass Spectroscopy (VPD-ICPMS) is the preferred analytical technique to measure trace metals on silicon wafers.
Appropriate handling prior to submitting the wafers to the lab is very critical. Below are 6 very important rules to follow to prevent cross-contamination from sources such as an unfiltered environment or human contact.
- Always handle wafers with vacuum wands, never with hands, and on the opposite side of the wafer from which you want analyzed.
- Open wafer boxes and perform all wafer movements in a cleanroom or at least in a laminar flow hood.
- Ship wafers in a cleaned wafer box, such as a cassette, FOUP, or FOSB.
- Place wafers in the cassette with the side to be analyzed facing up.
- After wafers are loaded in the wafer cassette, tape the cassette closed to prevent accidental opening and contamination from the outside air.
- Double bag the cassette with plastic and seal before placing in a box for shipping.
Improper wafer handling can lead to confusing and inaccurate data. Following these simple steps will ensure your samples are not contaminated by secondary sources.