Method for etching passivation layer of wafer
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsJun-Kai Peng, Wei-Kun Yeh, Chiarn-Lung Lee
Life of this patent
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Abstract
In an improved method for etching a groove n the uppermost layer of a semiconductor wafer, a conventional anisotropic etch is performed to achieve a narrow groove and an isotropic etch is performed to widen the groove at the device surface and thereby round the edges where the walls of the groove meet the surface of the wafer. During a later step of applying a protective tape to the device side of the wafer to protect it during a step of grinding the back of the wafer, the rounded edges of the groove are unlikely to cut through the adhesive layer of the tape and thereby cause particles of adhesive to remain on the wafer surface when the tape is removes.
Claims7
A method for processing a semiconductor wafer having a device surface and a back surface, the method comprising,
- etching the device surface with an anisotropic etch to form a groove with substantially vertical side walls and sharp edges where the side walls meet the device surface of the wafer,
- etching the device surface with an isotropic etch to form rounded edges where the edges were previously sharp,
- and after the etching steps, applying a grinding tape to the device surface of the wafer to protect the device side of the wafer during a subsequent step of grinding the back of the wafer, the grinding tape having an adhesive layer formed on a backing layer, and then grinding the back surface of the wafer to give the wafer a selected thickness,
- and removing the grinding tape and avoiding a residue of adhesive that would otherwise occur when sharp etched edges of the passivation layer cut into the adhesive layer of the grinding tape.
A method for processing a semiconductor wafer having a device surface and a back surface, the method comprising,
- etching the device surface with an anisotropic etch to form a groove with substantially vertical side walls and sharp edges where the side walls meet the device surface of the wafer,
- rounding the previously sharp edges,
- applying a grinding tape to the device surface of the wafer to protect the device side of the wafer during a subsequent step of grinding the back of the wafer, the grinding tape having an adhesive layer formed on a backing layer, and then grinding the back surface of the wafer to give the wafer a selected thickness,
- applying a second adhesive tape to the grinding tape and using a roller to obtain good adhesion between the two adhesive tapes, the step of rolling the second tape tending to force the adhesive layer of the grinding tape into the groove etched in the device surface of the wafer,
- and using the second tape to remove the grinding tape and avoiding a residue that would otherwise occur when sharp etched edges of the passivation layer cut into the adhesive layer of the grinding tape during the rolling step.
Dependencies are inferred from the claim text.