Double-sided imprinting

1. A double-sided imprinting method comprising:

drawing a first web along first rollers, the first web comprising a first template having a first imprinting feature;

dispensing a first resist on the first template;

waiting until the first resist spreads into the first imprinting feature of the first template;

loading a substrate onto the first template, such that a first side of the substrate is in contact with the first resist on the first template;

clamping the substrate onto the first template, such that the substrate is movable together with the first template;

dispensing a second resist on a second side of the substrate;

aligning a first reference mark on the first web with a second reference mark on a second web that includes a second template, wherein the second template has a second imprinting feature, such that the second imprinting feature is aligned with the first imprinting feature;

after the aligning, drawing the first web along the first rollers and drawing the second web along second rollers simultaneously at a same rate;

curing the first resist and the second resist, such that the cured first resist has a first imprinted feature corresponding to the first imprinting feature on the first side of the substrate and the cured second resist has a second imprinted feature corresponding to the second imprinting feature on the second side of the substrate; and

unloading the substrate with the first imprinted feature on the first side and the second imprinted feature on the second side.

2. The method of claim 1 , wherein the first imprinting feature comprises a grating feature and the grating feature is configured such that the first resist uniformly fills into the grating feature.

3. The method of claim 1 , wherein aligning the first reference mark on the first web with the second reference mark on the second web comprises:

locating the first reference mark and the second reference mark by using at least one of a camera system or a laser system.

4. The method of claim 1 , wherein the first reference mark is positioned ahead of the first imprinting feature on the first web along a direction of drawing the first web, and the second reference mark is positioned ahead of the second imprinting feature on the second web along the direction.

5. The method of claim 1 , further comprising:

locating the first reference mark on the first web using a detecting system positioned before one of the first rollers, the detecting system comprising at least a camera system or a laser system.

6. The method of claim 1 , further comprising:

before clamping the substrate onto the first template,

locating the first reference mark on the first web and a reference mark on the substrate; and

aligning the first reference mark on the first web with the reference mark on the substrate.

7. The method of claim 1 , wherein the first template comprises one or more pre-patterned through holes, and

wherein clamping the substrate onto the first web comprises holding with vacuum the substrate by a vacuum chuck through the one or more pre-patterned through holes.

8. The method of claim 1 , wherein the first rollers comprise two first z-rollers arranged in a horizontal direction, and the second rollers comprise two second z-rollers arranged in the horizontal direction.

9. The method of claim 8 , wherein the two first z-rollers define a first moving range for the first web and the two second z-rollers define a second moving range for the second web, and

wherein the first moving range is larger than the second moving range and encloses the second moving range.

10. The method of claim 8 , wherein the first rollers and the second rollers are arranged to define a vertical distance between the first template and the second template, and

wherein the vertical distance is defined such that the second resist is pressed onto the second side of the substrate and filled into the second imprinting feature on the second template.

11. The method of claim 1 , further comprising:

before the curing, moving a squeegee roller onto the second web to push the second template into the second resist, such that the second resist fills into the second imprinting feature.

12. The method of claim 1 , further comprising:

after the aligning, moving the second rollers together with the second web to be in contact with the second resist on the second side of the substrate, such that the second template is pressed into the second resist and the second resist fills into the second imprinting feature.

13. The method of claim 1 , wherein unloading the substrate comprises:

pulling the second web away from one of the second rollers to separate from the substrate; and

unclamping the substrate and taking from the first web the substrate.

14. A double-sided imprinting method comprising:

drawing a first web along first rollers and drawing a second web along second rollers until a first template of the first web and a second template of the second web are brought together into an imprinting zone that is between adjacent two of the first rollers and between adjacent two of the second rollers;

aligning reference marks for the first template and the second template in the imprinting zone;

dispensing a first resist on a first side of a substrate and a second resist on a second side of the substrate;

feeding the substrate into the imprinting zone between the first template and the second template;

after the substrate is fed into the imprinting zone, pressing the first template and the second template onto the substrate in the imprinting zone, such that the first resist fills into a first imprinting feature of the first template on the first side of the substrate and the second resist fills into a second imprinting feature of the second template on the second side of the substrate;

curing the first resist and the second resist, such that the cured first resist has a first imprinted feature corresponding to the first imprinting feature on the first side of the substrate and the cured second resist has a second imprinted feature corresponding to the second imprinting feature on the second side of the substrate; and

unloading the substrate with the first imprinted feature on the first side and the imprinted feature on the second side.

15. The method of claim 14 , wherein pressing the first template and the second template onto the substrate comprises applying a first press dome on the first template and a second press dome on the second template,

wherein the method further comprises:

bringing the first press dome into contact with the first template and bringing the second press dome into contact with the second template; and

making a correction for alignment of the first template and the second template.

16. The method of claim 14 , wherein pressing the first template and the second template onto the substrate comprises:

moving a first squeegee roller onto the first web to push the first template into the first resist, such that the first resist fills into the first imprinting feature on the first template; and

moving a second squeegee roller onto the second web to push the second template into the second resist, such that the second resist fills into the second imprinting feature on the second template.

17. A double-sided imprinting method comprising:

drawing a first web along a first roller and a second roller, the first web comprising a first template having a first imprinting feature;

drawing a second web along a third roller and a fourth roller, the second web comprising a second template having a second imprinting feature, the first roller and the third roller being positioned opposite to each other and defining a nip;

aligning reference marks for the first template and the second template;

dispensing a first resist on one of a first side of a substrate and the first template;

dispensing a second resist on the second template;

simultaneously drawing the first template and the second template into the nip and feeding the substrate into the nip with the first imprinting feature facing the first side of the substrate and the second imprinting feature facing a second side of the substrate, such that the first resist is pressed by the first roller into the first imprinting feature on the first side of the substrate and the second resist is pressed by the third roller into the second imprinting feature on the second side of the substrate;

curing the first resist and the second resist, such that the cured first resist has a first imprinted feature corresponding to the first imprinting feature on the first side of the substrate and the cured second resist has a second imprinted feature corresponding to the second imprinting feature on the second side of the substrate; and

unloading the substrate with the first imprinted feature on the first side and the second imprinted feature on the second side,

wherein unloading the substrate comprises:

reversely drawing the first web from the first roller and the second web from the third roller and retracting the substrate to separate the first template and the second template from the substrate.