摘要:
An overlay measurement recipe is checked for reliability as follows. A first pair of overlay layers (130, 150) is formed (610), and the recipe is used to obtain alignment measurements for the two layers. Then another pair of overlay layers (130, 150) is obtained (630), possibly using the same masks, but this time at least one of the layers (150) is offset from its previous position. The overlay measurement recipe is used again to obtain alignment measurements (640). The two sets of measurements are checked against the offset of the layers from their previous positions to validate the recipe. Other embodiments are also provided.
摘要:
A pillar array is printed in positive photoresist using an optical mask (108) having an array of features (310) corresponding to the pillars. The pillars' width/length dimensions are below the exposure wavelength. Superior results can be achieved (less peeling off of the pillars and less overexposure at the center of each pillar) if the mask features (310) are downsized relative to the pillars' target sizes, and the exposure energy is reduced. Negative photoresist (with a dark field mask) can be used, and can provide good results (in terms of pillars peeling-off) if the combined area of the features (410) corresponding to the pillars is smaller than the area between the features (410).
摘要:
In photolithographic exposure, a feature (144) of an optical mask is projected onto a dark area (160). The light intensity inside the dark area is reduced by providing a non-printable clear cutout (410) inside the feature. The optical mask has the same optical pathlength outside the feature (144) adjacent to the entire outer boundary of the feature as at the cutout, the optical pathlength being measured along the optical mask's thickness.
摘要:
In photolithographic exposure, a feature (144) of an optical mask is projected onto a dark area (160). The light intensity inside the dark area is reduced by providing a non-printable clear cutout (410) inside the feature. The optical mask has the same optical pathlength outside the feature (144) adjacent to the entire outer boundary of the feature as at the cutout, the optical pathlength being measured along the optical mask's thickness.
摘要:
In photolithographic exposure, the illumination pattern (120R) formed on a photosensitive surface (106) is a reverse of the pattern (130) on the optical mask (124). The reverse pattern (120R) is obtained using off-axis illumination when the photosensitive surface is at other than the best focus position.