Two step implant to improve line edge roughness and line width roughness
OwnerJohn Hautala, Huixiong Daiinventors
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Abstract
Methods of processing patterned photoresist to reduce line edge roughness and line width roughness on a semiconductor workpiece are disclosed. The method is performed after the photoresist has been patterned and before the etching process is commenced. Two implants, using different species, are performed at high tilt angles. In certain embodiments, the tilt angle may be 45° or more. Further, the implants are performed at twist angles such that the trajectory of the ions is nearly parallel to the patterned photoresist lines. In this way, the ions from the two implants glance the top and sidewalls of the photoresist lines. Using this technique, the LER and LWR of the photoresist lines may be reduced with minimal impact on the CD.
Claims20
A method of reducing line edge roughness (LER) and line width roughness (LWR) of a patterned photoresist disposed on a workpiece, wherein the patterned photoresist has sidewalls and a thickness known as a critical dimension (CD), and wherein the workpiece is disposed on a platen capable of twist about a rotational axis and tilt about a tilt axis, the method comprising:
- orienting the workpiece on the platen by selecting a twist angle of the platen so as to align a trajectory of an incoming ion beam to a primary photoresist direction and by selecting a high tilt angle, wherein the primary photoresist direction is parallel to the sidewalls;
- directing a first ion beam having a first species toward the workpiece after the orienting;
- and
- directing a second ion beam having a second species, different from the first species, toward the workpiece after directing the first ion beam while the workpiece remains oriented.
A method of reducing line edge roughness (LER) and line width roughness (LWR) of a patterned photoresist disposed on a workpiece, wherein the patterned photoresist has sidewalls and a thickness known as a critical dimension (CD), and wherein the workpiece is disposed on a platen capable of twist about a rotational axis and tilt about a tilt axis, the method comprising:
- orienting the workpiece on the platen by selecting a twist angle of the platen so as to align a primary photoresist direction to a trajectory of an incoming ion beam and by selecting a high tilt angle, wherein the primary photoresist direction is parallel to the sidewalls;
- directing a first ion beam comprising silicon ions toward the workpiece after the orienting;
- rotating the workpiece 180° after directing the first ion beam;
- directing the first ion beam toward the workpiece a second time after rotating;
- directing a second ion beam having a second species, different from the silicon ions, toward the workpiece;
- rotating the workpiece 180° after directing the second ion beam;
- and
- directing the second ion beam toward the workpiece a second time after rotating a second time.
A method of reducing line edge roughness (LER) and line width roughness (LWR) of a patterned photoresist disposed on a workpiece, wherein the patterned photoresist has sidewalls and a thickness known as a critical dimension (CD), and wherein the workpiece is disposed on a platen capable of twist about a rotational axis and tilt about a tilt axis, the method comprising:
- orienting the workpiece on the platen by selecting a twist angle of the platen so as to align a trajectory of an incoming ion beam to a primary photoresist direction and by selecting a high tilt angle, wherein the primary photoresist direction is parallel to the sidewalls;
- and
- directing an ion beam having an inert species toward the workpiece while the workpiece remains oriented.
Dependencies are inferred from the claim text.