Alignment method, transfer method and transfer apparatus

A transfer method for transferring a pattern or a thin film as a transfer material carried on a transparent carrier to a predetermined position of a substrate, comprising:

• a holding step of proximately holding the substrate formed with a first alignment mark on a surface and the carrier formed with the transfer material and a second alignment mark on a surface with the respective alignment mark formed surfaces facing each other;
• an imaging step of imaging both the first alignment mark and the second alignment mark collectively within a same field of view of a same imager via the carrier from a side opposite to the alignment mark formed surface of the carrier;
• a position detecting step of detecting positions of both the first alignment mark and the second alignment mark based on an image containing both the first alignment mark and the second alignment mark obtained by imaging;
• an aligning step of adjusting relative positions of the substrate and the carrier based on a detection result in the position detecting step;
• and
• a transferring step of transferring the transfer material on the surface of the carrier to the substrate by bringing the substrate and the carrier, the relative positions of which are adjusted, into contact, wherein:
• the first alignment mark includes more low spatial frequency components than the second alignment mark;
• the imaging step is performed in a state where a distance in an optical axis direction of the imager between the alignment mark formed surface of the substrate and the alignment mark formed surface of the carrier held proximate to each other is longer than the depth of field of the imager and the imager is focused on the alignment mark formed surface of the carrier;
• and
• in the position detecting step, a filtering process of removing high spatial frequency components from the image is performed and a center of gravity position of the first alignment mark is detected from the image after filtering.

A transfer apparatus for transferring a pattern or a thin film as a transfer material to a substrate, comprising:

• a holder that proximately holds the substrate formed with a first alignment mark on a surface and a carrier carrying the transfer material to be transferred to the substrate and a second alignment mark on a surface with the respective alignment mark formed surfaces facing each other;
• an imager configured for imaging both the first alignment mark and the second alignment mark collectively within a same field of view via the carrier from a side opposite to the alignment mark formed surface of the carrier;
• a position detector configured for detecting positions of both the first alignment mark and the second alignment mark based on an image containing both the first alignment mark and the second alignment mark imaged by the imager;
• and
• an aligner that adjusts relative positions of the substrate and the carrier based on a detection result of the position detector, wherein:
• the first alignment mark includes more low spatial frequency components than the second alignment mark;
• a distance in an optical axis direction of the imager between the alignment mark formed surface of the substrate and the alignment mark formed surface of the carrier held proximate to each other by the holder is longer than the depth of field of the imager;
• the imager performs imaging in a state where the alignment mark formed surface of the carrier is in focus;
• and
• the position detector performs a filtering process of removing high spatial frequency components from the image and detects a center of gravity position of the first alignment mark from the image after filtering.

An alignment method for arranging a first substrate and a second substrate opposite to each other and adjusting a mutual positional relationship, comprising:

• a holding step of proximately holding the first substrate formed with a first alignment mark on a surface and the second substrate formed with a second alignment mark on a surface with the respective alignment mark formed surfaces facing each other;
• an imaging step of imaging the first alignment mark and the second alignment mark within a same field of view of an imager via the second substrate from a side opposite to the alignment mark formed surface of the second substrate;
• a position detecting step of detecting positions of the first alignment mark and the second alignment mark based on an image obtained by imaging;
• and
• an aligning step of adjusting relative positions of the first substrate and the second substrate based on a detection result in the position detecting step, wherein:
• the imaging step is performed in a state where a distance in an optical axis direction of the imager between the alignment mark formed surface of the first substrate and that of the second substrate is longer than the depth of field of the imager and the imager is focused on the alignment mark formed surface of the second substrate;
• and
• in the position detecting step, a filtering process of removing high spatial frequency components from the image is performed and a center of gravity position of the first alignment mark is detected from the image after filtering wherein:
• center of gravity positions of the first alignment mark and the second alignment mark in the image are respectively detected in the position detecting step, and at least one of the first substrate and the second substrate is moved by a movement amount calculated based on the respective center of gravity positions of the first and second alignment marks in the aligning step;
• a plurality of first alignment marks are provided on the first substrate, whereas a plurality of second alignment marks corresponding to the first alignment marks are provided on the second substrate;
• a plurality of pairs of alignment marks, each pair including one first alignment mark and one second alignment mark corresponding to the first alignment mark, are respectively imaged by individual imagers in the imaging step;
• and
• the movement amount is calculated based on a virtual first figure formed by connecting the detected center of gravity positions of the plurality of first alignment marks and a virtual second figure formed by connecting the detected center of gravity positions of the plurality of second alignment marks in the aligning step.