After sorting and testing, the individual dies are physically separated. Diamond scribing, laser scribing, and diamond wheel sawing are used for die separation. Diamond scribing is the oldest method and involves scoring a line across the wafer surface with a diamond tip. The wafer is then bent along the line, causing a fracture and separation. Laser scribing is similar except that a laser is used to score the fracture line. Diamond sawing involves wet-cutting the substrates with a high-speed circular diamond saw. Sawing may be used to either partially cut and scribe the surface, or can be used to completely cut through the wafer.
The following are the potential hazards of die separation.
Vaporization Products - Laser
- Possible employee exposure to vaporization products from laser scribing.
- Identify vaporization hazards and perform appropriate exposure evaluations.
- Perform exposure measurements for the solvents used.
- 29 CFR 1910.1000 Table Z-1 contains permissible exposure limits for various chemicals.
- Provide appropriate ventilation to reduce concentration levels in the air.
- Use respiratory protection when necessary to further reduce exposure and protect employees. [29 CFR 1910.134]
- Occupational Health Guidelines for Chemical Hazards. US Department of Health and Human Services (DHHS), National Institute for Occupational Safety and Health (NIOSH) Publication No. 81-123, (1981, January). Provides a table of contents of guidelines for many hazardous chemicals. The files provide technical chemical information, including chemical and physical properties, health effects, exposure limits, and recommendations for medical monitoring, personal protective equipment (PPE), and control procedures.
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