Method for processing workpiece

A method for etching a workpiece using a plasma processing apparatus, wherein

• the plasma processing apparatus includes a holding structure which holds the workpiece, and a processing container which accommodates the holding structure,
• the holding structure is rotatable by 360 degrees in the processing container around an inclination shaft provided in the processing container,
• the inclination shaft intersects the holding structure,
• an axis of the inclination shaft is parallel to a surface of an electrode plate of an upper electrode provided on a ceiling side of the processing container and a surface of the workpiece held by the holding structure,
• in a state in which the surface of the workpiece held by the holding structure and the surface of the electrode plate are parallel to each other and face each other, a first center axis of the workpiece and a second center axis of the processing container overlap with each other and a first direction of the first center axis and a second direction of the second center axis are the same,
• the first center axis is perpendicular to the surface of the workpiece,
• the first direction is directed upward of the surface of the workpiece,
• the second center axis is perpendicular to the surface of the electrode plate,
• the second direction is directed toward the electrode plate provided on the ceiling side of the processing container from a bottom portion side of the processing container,
• the first center axis is inclined with respect to the second center axis as the holding structure rotates around the inclination shaft,
• the method comprises:
• a first step of generating a plasma in the processing container in which the workpiece is held by the holding structure, in a state in which the first direction and the second direction are maintained to form a first angle;
• and
• a second step of, after execution of the first step, generating a plasma in the processing container in which the workpiece is held by the holding structure, in a state in which the first direction and the second direction are maintained to form a second angle,
• the first angle and the second angle are −180 degrees to +180 degrees,
• an absolute value of the first angle and an absolute value of the second angle are different from each other
• the workpiece includes a laminated region and a mask provided on the laminated region,
• the laminated region includes a plurality of first layers and a plurality of second layers,
• the first layers and the second layers are alternately laminated along a lamination direction,
• the first layers and the second layers being made of different materials,
• the absolute value of the first angle is smaller than the absolute value of the second angle,
• in the first step, the laminated region is etched in the lamination direction using the mask, and, by the etching, a groove is formed in the laminated region, and
• in the second step, the first layers exposed to an inside of the groove are selectively etched.