Alignment method based on holographic lithography, system and device

An alignment method based on holographic lithography, applied to a holographic lithography system, wherein the holographic lithography system comprises a holographic mask and a silicon wafer sequentially arranged along the transmission direction of an illumination light, and the method comprises:

• controlling the illumination light to generate an alignment image after passing through an alignment image area of the holographic mask, wherein the alignment image comprises a first period image and a second period image, and the period of the first period image is different from that of the second period image;
• obtaining a light intensity corresponding to the first period image and a light intensity corresponding to the second period image generated according to the alignment image;
• and
• adjusting a relative position of the silicon wafer and/or the holographic mask to determine an alignment position between the silicon wafer and the holographic mask with respect to the holographic lithography according to a preset alignment condition, wherein the preset alignment condition is that the light intensity corresponding to the first period image and the light intensity corresponding to the second period image are equal and both reach a maximum value;
• wherein the holographic lithography system further comprises a grating and a light intensity sensor sequentially arranged between the holographic mask and the silicon wafer along the transmission direction of the illumination light,
• the grating and the silicon wafer are relatively fixed,
• the grating is correspondingly provided with a first alignment area corresponding to the first period image and a second alignment area corresponding to the second period image,
• the first period image comprises a first period fringe and a second period fringe with the same period,
• the second period image comprises a third period fringe and a fourth period fringe with the same period,
• a length direction of the first period fringe and a length direction of the third period fringe are the same and perpendicular to a length direction of the second period fringe and a length direction of the fourth period fringe,
• the first alignment area comprises a first alignment grating and a second alignment grating with the same shapes as the first period fringe and the second period fringe respectively, and
• the second alignment area comprises a third alignment grating and a fourth alignment grating with the same shapes as the third period fringe and the fourth period fringe respectively;
• wherein obtaining the light intensity corresponding to the first period image and the light intensity corresponding to the second period image generated according to the alignment image comprises:
• obtaining a light intensity corresponding to the first alignment grating, a light intensity corresponding to the second alignment grating, a light intensity corresponding to the third alignment grating, and a light intensity corresponding to the fourth alignment grating when the illumination light sequentially passes through the alignment image area and the grating;
• wherein adjusting the relative position of the silicon wafer and/or the holographic mask to determine the alignment position between the silicon wafer and the holographic mask with respect to the holographic lithography according to the preset alignment condition comprises:
• adjusting a relative position of the silicon wafer and/or the holographic mask in a first direction to determine a first position where the light intensity corresponding to the first alignment grating and the light intensity corresponding to the third alignment grating are equal and both reach a maximum value, wherein the first direction is perpendicular to the length direction of the first period fringe;
• and
• adjusting a relative position of the silicon wafer and/or the holographic mask in a second direction to determine a second position where the light intensity corresponding to the second alignment grating and the light intensity corresponding to the fourth alignment grating are equal and both reach a maximum value, wherein the second direction is perpendicular to the length direction of the second period fringe.