Method for splitting semiconductor wafers

A method of splitting a semiconductor wafer, the method comprising:

• forming one or more epitaxial layers on the semiconductor wafer;
• forming a plurality of device structures in the one or more epitaxial layers;
• forming a metallization layer and/or a passivation layer over the plurality of device structures;
• attaching a carrier to the semiconductor wafer with the one or more epitaxial layers, the carrier protecting the plurality of device structures and mechanically stabilizing the semiconductor wafer;
• forming a separation region within the semiconductor wafer, the separation region having at least one altered physical property which increases thermo-mechanical stress within the separation region relative to the remainder of the semiconductor wafer;
• and
• applying an external force to the semiconductor wafer such that at least one crack propagates along the separation region and the semiconductor wafer splits into two separate pieces, one of the pieces retaining the plurality of device structures,
• wherein applying the external force to the semiconductor wafer comprises applying ultrasonic vibrations to the semiconductor wafer.

A method of splitting a semiconductor wafer, the method comprising:

• forming one or more epitaxial layers on the semiconductor wafer;
• forming a plurality of device structures in the one or more epitaxial layers;
• forming a metallization layer and/or a passivation layer over the plurality of device structures;
• attaching a carrier to the semiconductor wafer with the one or more epitaxial layers, the carrier protecting the plurality of device structures and mechanically stabilizing the semiconductor wafer;
• forming a separation region within the semiconductor wafer, the separation region having at least one altered physical property which increases thermo-mechanical stress within the separation region relative to the remainder of the semiconductor wafer;
• and
• applying an external force to the semiconductor wafer such that at least one crack propagates along the separation region and the semiconductor wafer splits into two separate pieces, one of the pieces retaining the plurality of device structures,
• wherein applying the external force to the semiconductor wafer comprises:
• applying a polymer to the semiconductor wafer and/or the carrier, the polymer having a CTE (coefficient of thermal expansion) different from a CTE of the semiconductor wafer;
• and
• subjecting the polymer and the semiconductor wafer to a temperature process during which the polymer imparts mechanical stress to the semiconductor wafer.

A method of splitting a semiconductor wafer, the method comprising:

• forming one or more epitaxial layers on the semiconductor wafer;
• forming a plurality of device structures in the one or more epitaxial layers;
• forming a metallization layer and/or a passivation layer over the plurality of device structures;
• attaching a carrier to the semiconductor wafer with the one or more epitaxial layers, the carrier protecting the plurality of device structures and mechanically stabilizing the semiconductor wafer;
• forming a separation region within the semiconductor wafer, the separation region having at least one altered physical property which increases thermo-mechanical stress within the separation region relative to the remainder of the semiconductor wafer;
• and
• applying an external force to the semiconductor wafer such that at least one crack propagates along the separation region and the semiconductor wafer splits into two separate pieces, one of the pieces retaining the plurality of device structures,
• wherein the at least one altered physical property of the separation region comprises a plurality of microscopic cracks that are at least partially disconnected from one another within the separation region,
• wherein the plurality of microscopic cracks connect to one another in response to the external force, to form the at least one crack which propagates along the separation region,
• wherein the semiconductor wafer is a SiC wafer,
• wherein the at least one crack formed by the connection of the plurality of microscopic cracks in response to the external force has a saw-tooth pattern.