Method of Identifying Cracked Wafers
Original Publication Date: 1987-May-01
Included in the Prior Art Database: 2005-Feb-01
Cracks in silicon wafers can be revealed to the naked eye using various thin film liquids to magnify the appearance of the crack. The method allows scanning large surface areas at once to detect submicron cracks. The liquid used depends upon the surface properties of the wafer. For wafers whose surface will wet with water, including as-cut and sandblasted wafers, condensed water vapor works well. For hydrophobic wafers, materials such as alcohol or acetone can be used. Cracks in rough wafers cannot be seen by the naked eye and are difficult to find using microscopy or X-ray techniques. Cracks will appear on rough wafers after they are cooled to the dew point on a cold chuck. Moisture from the air condenses on the rough wafer as a thin film of water.