Double-sided imprinting

Abstract

To provide favorable double-sided imprinting.SOLUTION: Systems, apparatus and methods for double-sided imprinting are provided. An example system includes first rollers for moving a first web including a first template having a first imprinting feature, second rollers for moving a second web including a second template having a second imprinting feature, dispensers for dispensing resist, a locating system for locating reference marks on the first and second webs for aligning the first and second templates, a light source for curing the resist, and a moving system for feeding the substrate between the first and second templates and unloading the double-side-imprinted substrate from the first and second webs.SELECTED DRAWING: Figure 11B

Description

[Technical field]

[0001] (CROSS REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of the filing date of U.S. Provisional Application No. 62 / 511,172, filed May 25, 2017. The contents of U.S. Application No. 62 / 511,172 are incorporated herein by reference in their entirety.

[0002] The present disclosure relates generally to imprinting techniques, particularly for double-sided imprinting. [Background technology]

[0003] There are many challenges to overcome when developing processes and / or tools to move from creating single-sided imprints on a substrate to imprints on both sides from a template. Challenges may include positioning and aligning the substrate and template, locating reference features to aid in alignment, creating imprints without air entrapment and defects, and holding the substrate without damage. Summary of the Invention [Means for solving the problem]

[0004] The present disclosure describes methods, devices, and systems for double-sided imprinting that address the challenges described above.

[0005] One aspect of the disclosure includes a method for manufacturing a substrate, the method comprising the steps of: stretching a first web along a first roller and stretching a second web along a second roller, the first web comprising a first template and the second web comprising a second template; aligning reference marks on the first web and the second web such that the first template and the second template are aligned with one another; stretching the first web along the first roller in a first direction and exposing the first template to a first dispenser, stretching the second web along the second roller in a second direction and exposing the second template to a second dispenser; dispensing a first resist onto the first template by the first dispenser and dispensing a second resist onto the second template by the second dispenser; and exposing the first template and the second template with the first resist to a first template. the first template with the first resist and the second template with the second resist facing each other; inserting a substrate between the first template with the first resist and the second template with the second resist; curing the first resist and the second resist such that the cured first resist has a first imprinted feature associated with the first template on a first side of the substrate and the cured second resist has a second imprinted feature associated with the second template on a 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.

[0006] In some implementations, the method further includes: crimping the first and second webs at a location adjacent to the reference mark such that after the aligning step, the crimped first and second webs are moved with the first and second templates aligned with each other; and de-cramping the first and second webs such that after the curing step, the substrate with the cured first and second resists can pass through the gap between the first and second webs. The crimping of the first and second webs can include actuating a chuck with a clamp such that the chuck is on the first web and the clamp is on the second web. The chuck can include a vacuum chuck configured to chuck on the first web with a vacuum. In some examples, the chuck is configured to be movable along a rail parallel to an axis defined by the first roller, and the chuck and clamp are moved with the first and second webs after crimping. The chuck can be positioned on a pair of guides, each of which can be movable on a respective rail connected to the frame. Aligning the reference marks on the first web and the second web can include adjusting a relative position of the guides on the respective rails in at least one of an x, y, or theta direction.

[0007] The first roller and the second roller can be arranged such that after the inserting step, the substrate is moved together with the first template and the second template, and a first resist is pressed onto a first side of the substrate and filled into a first imprinting feature on the first template, and a second resist is pressed onto a second side of the substrate and filled into a second imprinting feature on the second template.

[0008] The method may further include moving a first squeegee roller over the first web and pressing the first template into the first resist such that the first resist fills into the first imprinting features on the first template, and moving a second squeegee roller over the second web and pressing the second template into the second resist such that the second resist fills into the second imprinting features on the second template. The first and second squeegee rollers may be positioned opposite each other while the first and second squeegees are moving together.

[0009] In some cases, aligning the reference marks on the first and second webs includes aligning a first reference mark on the first web with a second reference mark on the second web and aligning a third reference mark on the first web with a fourth reference mark on the second web. The first and third reference marks can define an area in which the substrate is configured to be imprinted with the first template. In some cases, aligning the reference marks on the first and second webs includes moving a z-roller of the first roller in at least one of the x, y, or theta directions. In some cases, aligning the reference marks on the first and second webs includes identifying the location of the reference marks by using at least one of a camera system or a laser system.

[0010] The first direction can be a counterclockwise direction and the second direction can be a clockwise direction. In some embodiments, the first roller includes at least one air turn roller configured to float the first web by air pressure. In some embodiments, the first roller includes at least one air turn roller configured to chuck the first web by vacuum.

[0011] In some embodiments, the first roller includes two first z-rollers arranged in a vertical direction, and the second roller includes two second z-rollers arranged in a vertical direction. Dispensing the first resist onto the first template by the first dispenser can include dispensing the first resist onto the first template when the first template is in a horizontal direction, and dispensing the second resist onto the second template by the second dispenser can include dispensing the second resist onto the second template when the second template is in a horizontal direction.

[0012] In some examples, inserting the substrate includes inserting the substrate by a first holder along an insertion direction. In some cases, unloading the substrate includes moving the substrate with the first and second imprinted features along a direction opposite to the insertion direction and unloading the substrate with the first and second imprinted features by a first holder. In some cases, unloading the substrate includes moving the substrate with the first and second imprinted features along the insertion direction and unloading the substrate with the first and second imprinted features by a second, different holder. The method can further include measuring a first tension of the first web by a first tension sensor and measuring a second tension of the second web by a second tension sensor. The method can further include controlling at least one of a temperature and a cleanliness of a chamber surrounding at least the first template and the second template.

[0013] The method can include locating a first reference mark on the first web using a detection system positioned upstream of one of the first rollers when the first web is stationary before the first template is stretched into the imprinting region. The method can include locating a first reference mark on the first web using a reference mark on the substrate, aligning the first reference mark on the first web with a reference mark on the substrate, and after alignment, pressing the first reference mark and moving the first web such that the first template is moved to an imprinting start position of the substrate in synchronization with the imprinting start position. The method can further include aligning the reference marks on the first and second webs, including measuring an angle of the first web by one or more sensors arranged on an edge of the first web, and repositioning the substrate based on the measured angle of the first web.

[0014] Another aspect of the disclosure features a system for double-sided imprinting including a first roller for moving a first web including a first template; a second roller for moving a second web including a second template; an alignment system configured to align reference marks on the first web and the second web such that the first template and the second template are aligned with one another; a first dispenser configured to dispense a first resist onto the first template; a second dispenser configured to dispense a second resist onto the second template; a loading system configured to insert a substrate between the first template and the second template; and a light source configured to harden the first resist and the second resist such that the hardened first resist has first imprinted features associated with the first template on a first side of the substrate and the hardened second resist has second imprinted features associated with the second template on a second side of the substrate. In operation, the first web is stretched along a first roller in a first direction to expose the first template to a first dispenser, the second web is stretched along a second roller in a second direction to expose the second template to a second dispenser, and then the first web is stretched along the first roller in a direction opposite to the first direction and the second web is stretched along the second roller in a direction opposite to the second direction so that the first template with the first resist and the second template with the second resist face each other.

[0015] In some implementations, the system further includes an unloading system configured to unload the substrate with the first imprinted feature on a first side and the second imprinted feature on a second side. In some cases, the loading system is configured to unload the substrate when the substrate with the first and second imprinted features is moved back to the loading system.

[0016] In some implementations, the system further includes a crimping system configured to crimp the first and second webs at a location adjacent the reference mark such that the crimped first and second webs are moved with the first and second templates aligned with each other, and to de-crimp the first and second webs such that the substrate with the hardened first and second resists can pass through the gap between the first and second webs. The crimping system can include a chuck configured to chuck the first web and a clamp configured to crimp the second web when actuated with the chuck. The chuck can include a vacuum chuck configured to chuck onto the first web using a vacuum. The chuck can be configured to be movable along a rail parallel to an axis defined by the first roller, and the chuck and clamp can be moved with the first and second webs after crimping the first and second webs. In some embodiments, the chuck is positioned on a pair of guides, each of the guides movable on a respective rail connected to the frame, and the alignment system is configured to align the reference marks on the first web and the second web by adjusting the relative positions of the guides on the respective rails in at least one of the x, y, or theta directions.

[0017] The first roller and the second roller can be arranged such that the substrate is moved with the first template and the second template, the first resist is pressed onto a first side of the substrate and filled into the first imprinting features on the first template, and the second resist is pressed onto a second side of the substrate and filled into the second imprinting features on the second template. The alignment system can be configured to align the reference marks on the first web and the second web by moving a z-roller of the first roller in at least one of an x, y, or theta direction. The system can further include a positioning system configured to identify locations of the reference marks on the first web and the second web for alignment, the positioning system can include at least one of a camera system or a laser system.

[0018] The first direction can be a counterclockwise direction and the second direction can be a clockwise direction. In some examples, the first roller includes at least one air turn roller configured to float the first web by air pressure. In some examples, the first roller includes at least one air turn roller configured to chuck the first web by vacuum. In some examples, the first roller includes two first z-rollers arranged in a vertical direction, the second roller includes two second z-rollers arranged in a vertical direction, the first dispenser can be configured to dispense the first resist onto the first template when the first template is in a horizontal direction, and the second dispenser is configured to dispense the second resist onto the second template when the second template is in a horizontal direction.

[0019] The system can further include first and second tension sensors configured to measure tension in the first and second webs, respectively. The system can further include a chamber configured to enclose the first and second templates, and a controller configured to control at least one of a temperature and cleanliness of the chamber.

[0020] A third aspect of the present disclosure provides a method for manufacturing a substrate, comprising the steps of stretching a first web along a first roller, the first web comprising a first template having a first imprinting feature; dispensing a first resist onto the first template; loading a substrate onto the first template such that a first side of the substrate contacts the first resist on the first template; pressing the substrate onto the first template such that the substrate is movable with the first template; dispensing a second resist onto a second side of the substrate; and aligning a first reference mark on the first web with a second template having a second imprinting feature such that the second imprinting feature is aligned with the first imprinting feature. and after the aligning step, stretching the first web along the first roller and stretching the second web along the second roller at the same speed simultaneously; hardening the first resist and the second resist such that the hardened first resist has a first imprinted feature corresponding to the first imprinted feature on the first side of the substrate and the hardened second resist has a second imprinted feature corresponding to the second imprinted 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.

[0021] The method can further include waiting until the first resist diffuses into the first imprinting features of the first template. The first imprinting features can include grating features, and the grating features can be configured such that the first resist uniformly fills into the grating features.

[0022] The first reference mark can be positioned in front of a first imprinting feature on the first web along a direction of stretching the first web, and the second reference mark can be positioned in front of a second imprinting feature on the second web along this direction. In some examples, the first template includes one or more pre-patterned through-holes, and compressing the substrate onto the first web includes holding the substrate under vacuum with a vacuum chuck through the one or more pre-patterned through-holes.

[0023] In some implementations, the first roller includes two first z rollers arranged in a horizontal direction, and the second roller includes two second z rollers arranged in a horizontal direction. The two first z rollers can define a first range of movement for the first web, and the two second z rollers can define a second range of movement for the second web, and the first range of movement can be greater than and encompass the second range of movement. In some cases, the first roller and the second roller are arranged to define a vertical distance between the first template and the second template, and the vertical distance can be defined such that the second resist is pressed onto the second side of the substrate and filled into the second imprinting features on the second template.

[0024] The method can further include moving a second squeegee roller over the second web and pressing the second template into the second resist such that the second resist fills into the second imprinting features prior to the curing step. The method can further include moving a second roller with the second web into contact with the second resist on the second side of the substrate after the aligning step such that the second template is pressed into the second resist and the second resist fills into the second imprinting features.

[0025] In some embodiments, unloading the substrate includes pulling the second web away from one of the second rollers to separate it from the substrate, and depressing the substrate and removing the substrate from the first web.

[0026] A fourth aspect of the present disclosure provides a method and apparatus for manufacturing a substrate, the method comprising: a first roller for moving a first web including a first template having a first imprinting feature; a second roller for moving a second web including a second template having a second imprinting feature; a first dispenser configured to dispense a first resist onto the first template; a loading system configured to load a substrate onto the first template such that a first side of the substrate contacts the first resist on the first template; a pressing system configured to press the substrate onto the first web such that the substrate is movable with the first web; a second dispenser configured to dispense a second resist onto a second side of the substrate; The system for double-sided imprinting includes a positioning system configured to locate a first reference mark on the first web with a second reference mark on the second web to align with the reference mark, a light source configured to harden the first resist and the second resist such that the hardened first resist has a first imprinted feature corresponding to the first imprinted feature on the first side of the substrate and the hardened second resist has a second imprinted feature corresponding to the second imprinted feature on the second side of the substrate, and an unloading system configured to unload the substrate with the first imprinted feature on the first side and the second imprinted feature on the second side. After the first and second reference marks are aligned with each other, the first and second webs are stretched simultaneously at the same speed.

[0027] The first imprinting feature of the first template can include a grating feature, and the grating feature can be configured such that the first resist uniformly fills into the grating feature. The first reference mark can be positioned in front of the first imprinting feature on the first web along a direction of extending the first web, and the second reference mark is positioned in front of the second imprinting feature on the second web along this direction. The first template can include one or more pre-patterned through-holes, and the compression system includes a vacuum chuck configured to hold the substrate with a vacuum through the one or more pre-patterned through-holes.

[0028] In some implementations, the first roller includes two first z rollers arranged in a horizontal direction, and the second roller includes two second z rollers arranged in a horizontal direction. The two first z rollers can define a first range of movement for the first web, and the two second z rollers can define a second range of movement for the second web, the first range of movement being greater than the second range of movement and encompassing the second range of movement. The first roller and the second roller can be arranged to define a vertical distance between the first template and the second template, and the vertical distance can be defined such that the second resist is pressed onto the second side of the substrate and filled into the second imprinting features on the second template.

[0029] The first dispenser, the loading system, the second dispenser, the positioning system, the light source, and the unloading system can be arranged sequentially along a direction of extending the first web along the first roller. The system can further include a squeegee roller configured to apply pressure on the second web and urge the second template into the second resist such that the second resist fills into the second imprinting features of the second template.

[0030] The first roller can include at least one air turn roller configured to float the first web by air pressure. The second roller can be configured to be movable with the second web and to contact the second resist on the second side of the substrate after the aligning step, such that the second template is pressed into the second resist and the second resist fills into the second imprinting features. In some embodiments, the loading system can include an equipment front end module (EFEM) and the unloading system can include a second EFEM. In some embodiments, the positioning system includes at least one of a camera system or a laser system. The system can further include an alignment system configured to align a first reference mark on the first web with a second reference mark on the second web.

[0031] A fifth aspect of the present disclosure provides a method for fabricating a substrate, comprising the steps of stretching a first web along a first roller and stretching a second web along a second roller until a first template of a first web and a second template of a second web are brought together into an imprinting zone; aligning reference marks for the first template and the second template; dispensing a first resist onto a first side of the substrate and dispensing a second resist onto a second side of the substrate; feeding the substrate into the imprinting zone between the first template and the second template; and dispensing the first resist into a first imprinting feature of the first template on the first side of the substrate and dispensing the second resist into a second imprinting feature of the first template. pressing the first template and the second template onto the substrate such that the first imprinted feature fills into a second imprinted feature of the second template on the second side of the substrate; hardening the first resist and the second resist such that the hardened first resist has a first imprinted feature corresponding to the first imprinted feature on the first side of the substrate and the hardened second resist has a second imprinted feature corresponding to the second imprinted 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.

[0032] In some cases, pressing the first template and the second template onto the substrate can include applying a first press dome onto the first template. In some cases, pressing the first template and the second template onto the substrate can include applying a second press dome onto the second template.

[0033] In some implementations, pressing the first template and the second template onto the substrate includes moving a first squeegee roller over the first web and pressing the first template into the first resist such that the first resist fills into the first imprinting features on the first template, and moving a second squeegee roller over the second web and pressing the second template into the second resist such that the second resist fills into the second imprinting features on the second template. The first and second squeegee rollers can be positioned opposite each other while moving the first and second squeegees together.

[0034] The method may further include contacting the first press dome with the first template and the second press dome with the second template, and making a correction for alignment of the first template and the second template. The second press dome may include a glass dome or an annular ring vacuum chuck. The first press dome may include a glass dome or an annular ring vacuum chuck. Unloading the substrate may include pulling the first web off one of the first rollers and pulling the second web off one of the second rollers to separate the first template and the second template from the substrate.

[0035] In some cases, the substrate is rigid and the step of feeding the substrate includes presenting the substrate by gripping an edge of the substrate using a holder. In some cases, the substrate is flexible and the step of feeding the substrate includes stretching the substrate from a roll of blank substrates. The method can further include applying a first protective film on the hardened first resist on the first side of the substrate after the substrate is separated from the first template, and applying a second protective film on the hardened second resist on the second side of the substrate after the substrate is separated from the second template. The method can further include rolling the substrate with the hardened first resist on the first side and the hardened second resist on the second side over a roller.

[0036] A sixth aspect of the present disclosure provides a method for manufacturing a substrate, the method comprising the steps of: stretching a first web along a first roller and a second roller, the first web comprising a first template having a first imprinting feature; stretching 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 each other to define a nip; aligning reference marks for the first template and the second template; dispensing a first resist onto one of a first side of a substrate and the first template; dispensing a second resist onto one of a second side of the substrate and the second template; and pressing the first resist into the first imprinting feature on the first side of the substrate by the first roller. simultaneously extending the first template and the second template into the nip such that the second resist is pressed by a third roller into the second imprinting feature on the second side of the substrate, and delivering the substrate into the nip with the first imprinting feature facing the first side of the substrate and the second imprinting feature facing the second side of the substrate; hardening the first resist and the second resist such that the hardened first resist has a first imprinted feature corresponding to the first imprinting feature on the first side of the substrate and the hardened 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.

[0037] In some cases, unloading the substrate includes pulling the first web off the second roller and the second web off the fourth roller to separate the first and second templates from the substrate. In some cases, unloading the substrate includes back-stretching the first web off the first roller and the second web off the third roller to retract the substrate to separate the first and second templates from the substrate.

[0038] A seventh aspect of the present disclosure provides a method for fabricating a substrate comprising: a first roller configured to move a first web including a first template having a first imprinting feature; a second roller configured to move a second web including a second template having a second imprinting feature; one or more dispensers configured to dispense resist; a positioning system configured to identify locations of reference marks on the first and second webs for aligning the first and second templates; and a method for fabricating a substrate comprising the steps of: applying a first imprinting feature to a first web of a substrate; The system for double-sided imprinting includes a light source configured to harden a resist such that the hardened second resist has a first imprinted feature corresponding to the first imprinted feature on the side and the first imprinted feature corresponds to the second imprinted feature on the second side of the substrate, and a movement system configured to deliver the substrate between the first template and the second template and unload the substrate with the first imprinted feature on the first side and the second imprinted feature on the second side. The dispenser can be configured to dispense the first resist onto one of the first side of the substrate and the first template and dispense the second resist onto one of the second side of the substrate and the second template.

[0039] In some implementations, one of the first rollers and one of the second rollers are positioned opposite each other to define a nip, and the movement system is configured to feed the substrate into the nip as the first template and the second template are extended into the nip with the first imprinting feature facing the first side of the substrate and the second imprinting feature facing the second side of the substrate, such that the first resist is pressed into the first imprinting feature on the first side of the substrate by the first roller and the second resist is pressed into the second imprinting feature on the second side of the substrate by the third roller.

[0040] In some cases, the first web is pulled away from another of the first rollers and the second web is pulled away from another of the second rollers positioned opposite one of the first rollers such that the substrate is separated from the first and second templates. In some cases, the movement system is configured to retract the substrate and separate it from the first and second templates as the first and second webs are reverse stretched away from one of the first and second rollers, respectively.

[0041] In some implementations, the system further includes a pressing system configured to press the first template and the second template onto the substrate such that the first resist fills into first imprinting features of the first template on a first side of the substrate and the second resist fills into second imprinting features of the second template on a second side of the substrate.

[0042] In some embodiments, the pressing system includes a first press dome configured to be applied over the first template. The first press dome can include a glass dome or an annular ring vacuum chuck. In some embodiments, the pressing system includes a second press dome configured to be applied over the second template. The second press dome can include a glass dome or an annular ring vacuum chuck. The system can further include a compensation system configured to compensate for alignment of the first template and the second template when the first press dome is pressed into contact with the first template and the second press dome is pressed into contact with the second template.

[0043] In some implementations, the system includes a first squeegee roller configured to be moved over the first web and to press the first template into the first resist so that the first resist fills into the first imprinting features on the first template, and a second squeegee roller configured to be moved over the second web and to press the second template into the second resist so that the second resist fills into the second imprinting features on the second template. The first and second squeegee rollers can be positioned opposite each other while the first and second squeegees are moved together.

[0044] In some cases, the motion system includes a holder configured to grip an edge of the substrate. In some cases, the system includes rollers for the blank substrate, and the motion system is configured to rotate the rollers to feed the substrate.

[0045] In some implementations, the system further includes a first roller of a first protective film configured to be applied over the hardened first resist on the first side of the substrate and a second roller of a second protective film configured to be applied over the hardened second resist on the second side of the substrate. The system can further include a roller configured to be rotated and to receive the substrate with the hardened first resist on the first side and the hardened second resist on the second side.

[0046] The details of one or more disclosed implementations are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages will become apparent from the description, drawings, and claims. The present specification also provides, for example, the following items: (Item 1) 1. A double-sided imprinting method comprising the steps of: stretching a first web along a first roller and a second web along a second roller, the first web comprising a first template and the second web comprising a second template; aligning reference marks on the first web and the second web such that the first template and the second template are aligned with one another; stretching the first web along the first roller in a first direction to expose the first template to a first dispenser, and stretching the second web along the second roller in a second direction to expose the second template to a second dispenser; Dispensing a first resist onto the first template by the first dispenser and dispensing a second resist onto the second template by the second dispenser; stretching the first web along the first roller in a direction opposite to the first direction and stretching the second web along the second roller in a direction opposite to the second direction such that the first template with the first resist and the second template with the second resist face each other; inserting a substrate between the first template with the first resist and the second template with the second resist; hardening the first resist and the second resist such that the hardened first resist has first imprinted features associated with the first template on a first side of the substrate and the hardened second resist has second imprinted features associated with the second template on a second side of the substrate; unloading the substrate with the first imprinted feature on the first side and the second imprinted feature on the second side; A method comprising: (Item 2) after said aligning, crimping the first and second webs adjacent the reference mark such that the crimped first and second webs are moved with the first and second templates aligned with one another; decompressing the first web and the second web after the curing so that the substrate with the cured first resist and second resist can pass through a gap between the first web and the second web. The method of claim 1, further comprising: (Item 3) 3. The method of claim 2, wherein crimping the first web and the second web includes actuating the chuck with the clamp such that the chuck is on the first web and the clamp is on the second web. (Item 4) 4. The method of claim 3, wherein the chuck comprises a vacuum chuck configured to chuck onto the first web using a vacuum. (Item 5) the chuck is configured to be movable along a rail parallel to an axis defined by the first roller; The chuck and the clamp are moved together with the first web and the second web after the crimping. The method according to item 3. (Item 6) 6. The method of claim 5, wherein the chuck is positioned on a pair of guides, each of the guides being movable on a respective rail connected to a frame. (Item 7) 7. The method of claim 6, wherein aligning reference marks on the first web and the second web includes adjusting a relative position of the guides on the respective rails in at least one of an x, y, or theta direction. (Item 8) 2. The method of claim 1, wherein the first roller and the second roller are arranged such that after the inserting, the substrate is moved together with the first template and the second template, the first resist is pressed onto a first side of the substrate and filled into a first imprinting feature on the first template, and the second resist is pressed onto a second side of the substrate and filled into a second imprinting feature on the second template. (Item 9) moving a first squeegee roller over the first web to press the first template into the first resist such that the first resist fills into first imprinting features on the first template; moving a second squeegee roller over the second web to press the second template into the second resist such that the second resist fills into second imprinting features on the second template; The method of claim 1, further comprising: (Item 10) 10. The method of claim 9, wherein the first squeegee roller and the second squeegee roller are positioned opposite one another while moving the first squeegee and the second squeegee together. (Item 11) 2. The method of claim 1, wherein aligning reference marks on the first web and the second web includes aligning a first reference mark on the first web with a second reference mark on the second web and aligning a third reference mark on the first web with a fourth reference mark on the second web. (Item 12) Item 12. The method of item 11, wherein the first reference mark and the third reference mark define an area in which the substrate is configured to be imprinted with the first template. (Item 13) 2. The method of claim 1, wherein aligning reference marks on the first web and the second web includes moving a z-roller of the first roller in at least one of an x, y, or theta direction. (Item 14) 2. The method of claim 1, wherein aligning reference marks on the first web and the second web includes identifying locations of the reference marks by using at least one of a camera system or a laser system. (Item 15) Item 10. The method of item 1, wherein the first roller comprises at least one air turn roller configured to float the first web by air pressure. (Item 16) Item 10. The method of item 1, wherein the first roller comprises at least one air turn roller configured to chuck the first web by vacuum. (Item 17) 2. The method of claim 1, wherein the first direction is a counterclockwise direction and the second direction is a clockwise direction. (Item 18) 2. The method of claim 1, wherein the first roller comprises two first z-rollers arranged in a vertical direction, and the second roller comprises two second z-rollers arranged in the vertical direction. (Item 19) dispensing the first resist onto the first template by the first dispenser includes dispensing the first resist onto the first template when the first template is in a horizontal orientation; dispensing the second resist onto the second template by the second dispenser includes dispensing the second resist onto the second template when the second template is in the horizontal orientation. Item 19. The method according to item 18. (Item 20) inserting the substrate includes inserting the substrate by a first holder along an insertion direction; Unloading the substrate comprises: moving the substrate with the first and second imprinted features along a direction opposite to the insertion direction and unloading the substrate with the first and second imprinted features by the first holder; and moving the substrate with the first and second imprinted features along the insertion direction and unloading the substrate with the first and second imprinted features by a second, different holder. 2. The method according to claim 1, comprising one of the steps: (Item 21) Measuring a first tension in the first web with a first tension sensor; measuring a second tension in the second web with a second tension sensor; The method of claim 1, further comprising: (Item 22) Item 10. The method of item 1, further comprising controlling at least one of a temperature and a cleanliness of a chamber surrounding at least the first template and the second template. (Item 23) 2. The method of claim 1, further comprising: prior to extending the first template into an imprinting area, identifying a location of a first reference mark on the first web when the first web is stationary using a detection system positioned upstream of one of the first rollers. (Item 24) locating a first reference mark on the first web using a reference mark on the substrate; and aligning the first reference mark on the first web with the reference mark on the substrate; pressing the first reference mark and moving the first web so that the first template is moved to an imprinting start position of the substrate in synchronization with the imprinting start position of the substrate after the alignment; The method of claim 1, further comprising: (Item 25) measuring an angle of the first web with one or more sensors arranged on an edge of the first web; repositioning the substrate based on the measured angle of the first web. The method of claim 1, further comprising: (Item 26) 1. A system for double-sided imprinting, comprising: a first roller for moving a first web including the first template; a second roller for moving a second web including the second template; an alignment system configured to align reference marks on the first web and the second web such that the first template and the second template are aligned with one another; and a first dispenser configured to dispense a first resist onto the first template; a second dispenser configured to dispense a second resist onto the second template; and a loading system configured to insert a substrate between the first template and the second template; and a light source configured to harden the first resist and the second resist such that the hardened first resist has first imprinted features associated with the first template on a first side of the substrate and the hardened second resist has second imprinted features associated with the second template on a second side of the substrate; Equipped with In operation, the first web is stretched along the first roller in a first direction to expose the first template to the first dispenser, the second web is stretched along the second roller in a second direction to expose the second template to the second dispenser, and then the first web is stretched along the first roller in a direction opposite to the first direction, and the second web is stretched along the second roller in a direction opposite to the second direction, such that the first template with the first resist and the second template with the second resist face each other. system. (Item 27) 1. A double-sided imprinting method comprising the steps of: stretching a first web along a first roller, the first web comprising a first template having a first imprinting feature; Dispensing a first resist onto the first template; loading the substrate onto the first template such that a first side of the substrate contacts the first resist on the first template; compressing the substrate onto the first template such that the substrate is movable with the first template; Dispensing a second resist onto a second side of the substrate; aligning a first reference mark on the first web with a second reference mark on a second web including a second template having the second imprinting feature such that the second imprinting feature is aligned with the first imprinting feature; after said aligning, stretching the first web along the first roller and stretching the second web along the second roller simultaneously at the same speed; hardening the first resist and the second resist such that the hardened first resist has first imprinted features corresponding to the first imprinted features on a first side of the substrate and the hardened second resist has second imprinted features corresponding to the second imprinted features on a second side of the substrate; unloading the substrate with the first imprinted feature on the first side and the second imprinted feature on the second side; A method comprising: (Item 28) 1. A system for double-sided imprinting, comprising: a first roller for moving a first web including a first template having a first imprinting feature; a second roller for moving a second web including a second template having second imprinting features; a first dispenser configured to dispense a first resist onto the first template; a loading system configured to load the substrate onto the first template such that a first side of the substrate contacts the first resist on the first template; a crimping system configured to crimp the substrate onto the first web such that the substrate is movable with the first web; a second dispenser configured to dispense a second resist onto a second side of the substrate; a positioning system configured to identify a location of a first reference mark on the first web with a second reference mark on the second web to align the first reference mark with a second reference mark; a light source configured to harden the first resist and the second resist such that the hardened first resist has first imprinted features corresponding to the first imprinted features on a first side of the substrate and the hardened second resist has second imprinted features corresponding to the second imprinted features on a second side of the substrate; an unloading system configured to unload the substrate with the first imprinted feature on the first side and the second imprinted feature on the second side; Equipped with After the first and second reference marks are aligned with one another, the first and second webs are stretched simultaneously at the same speed. system. (Item 29) 1. A double-sided imprinting method comprising the steps of: stretching the first web along a first roller and the second web along a second roller until a first template on a first web and a second template on a second web are brought together into an imprinting zone; aligning reference marks for the first template and the second template; Dispensing a first resist onto a first side of a substrate and dispensing a second resist onto a second side of the substrate; delivering the substrate into the imprinting zone between the first template and the second template; pressing the first template and the second template onto the substrate such that the first resist fills into first imprinting features of the first template on a first side of the substrate and the second resist fills into second imprinting features of the second template on a second side of the substrate; hardening the first resist and the second resist such that the hardened first resist has first imprinted features corresponding to the first imprinted features on a first side of the substrate and the hardened second resist has second imprinted features corresponding to the second imprinted features on a second side of the substrate; unloading the substrate with the first imprinted feature on the first side and the second imprinted feature on the second side; A method comprising: (Item 30) 1. A double-sided imprinting method comprising the steps of: stretching a first web along a first roller and a second roller, the first web comprising a first template having a first imprinting feature; stretching 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 positioned opposite one another to define a nip; aligning reference marks for the first template and the second template; Dispensing a first resist onto one of a first side of a substrate and the first template; dispensing a second resist onto one of a second side of the substrate and the second template; simultaneously extending the first template and the second template into the nip such that the first resist is pressed by the first roller into the first imprinting features on a first side of the substrate and the second resist is pressed by the third roller into the second imprinting features on a second side of the substrate, and delivering the substrate into the nip with the first imprinting features facing a first side of the substrate and the second imprinting features facing a second side of the substrate; hardening the first resist and the second resist such that the hardened first resist has first imprinted features corresponding to the first imprinted features on a first side of the substrate and the hardened second resist has second imprinted features corresponding to the second imprinted features on a second side of the substrate; unloading the substrate with the first imprinted feature on the first side and the second imprinted feature on the second side; A method comprising: (Item 31) 1. A system for double-sided imprinting, comprising: a first roller configured to move a first web including a first template having a first imprinting feature; a second roller configured to move a second web including a second template having second imprinting features; and one or more dispensers configured to dispense the resist; a positioning system configured to identify locations of reference marks on the first web and the second web for aligning the first template and the second template; and a light source configured to harden a first resist such that the hardened first resist has first imprinted features corresponding to the first imprinted features on a first side of a substrate and a second resist such that the hardened second resist has second imprinted features corresponding to the second imprinted features on a second side of the substrate; a translation system configured to deliver the substrate between the first template and the second template and unload the substrate with the first imprinted feature on the first side and the second imprinted feature on the second side; A system comprising: [Brief description of the drawings]

[0047] [Figure 1] FIG. 1 shows a schematic diagram of an exemplary imprinting tool with direct annular template chucking with a web dome.

[0048] [Diagram 2] FIG. 2 shows a schematic diagram of an exemplary imprinting tool with indirect template chucking with a glass dome.

[0049] [Figure 3A] FIG. 3A shows a schematic diagram of an exemplary template vacuum chucking.

[0050] [Figure 3B] FIG. 3B shows a schematic diagram of an exemplary air / vacuum bar chucking.

[0051] [Figure 4A]FIG. 4A shows a schematic diagram of exemplary alternating regions of pressure and vacuum.

[0052] [Figure 4B] FIG. 4B shows a schematic diagram of an example of a glass dome template backing plate with a substrate pressure dome.

[0053] [Figure 5-1] 5A-5B show schematic diagrams of an example of locating a reference mark on a template.

[0054] [Figure 5-2] 5C-5D show schematic diagrams of an embodiment of locating a reference mark on a substrate.

[0055] [Figure 5-3] 5E-5F show schematic diagrams of an example of locating a reference mark on a template.

[0056] [Figure 5-4] 5G-5H show schematic diagrams of an embodiment of side-to-side imprinting alignment with a vacuum chuck.

[0057] [Figure 6A] FIG. 6A shows a schematic diagram of an example of using a squeegee roller during imprinting.

[0058] [Figure 6B] FIG. 6B shows a schematic diagram of another embodiment of using a squeegee roller during imprinting.

[0059] [Figure 7A] FIG. 7A shows a schematic diagram of an example of implementing the theta adjustment method.

[0060] [Figure 7B] FIG. 7B shows a schematic diagram of an example of implementing a web angle measurement method.

[0061] [Figure 8] FIG. 8 shows a schematic diagram of an exemplary system for producing double-sided imprints on a substrate.

[0062] [Figure 9] FIG. 9 shows a schematic diagram of another exemplary system for forming imprints on both sides of a substrate at once.

[0063] [Figure 10] FIG. 10 shows a schematic diagram of an exemplary system using dual glass dome imprinting in conjunction with low cost flexible substrates in roll form.

[0064] [Figure 11A] FIG. 11A shows a schematic diagram of an exemplary tool for double-sided imprinting.

[0065] [Figure 11B] FIG. 11B shows a schematic diagram of another exemplary tool for double-sided imprinting.

[0066] [Figure 12A-1] 12A-1-12I show schematic diagrams of an example procedure for using the tool of FIG. 11A for double-sided imprinting. [Figure 12A-2] 12A-1-12I show schematic diagrams of an example procedure for using the tool of FIG. 11A for double-sided imprinting. [Figure 12A-3] 12A-1-12I show schematic diagrams of an example procedure for using the tool of FIG. 11A for double-sided imprinting. [Figure 12A-4] 12A-1-12I show schematic diagrams of an example procedure for using the tool of FIG. 11A for double-sided imprinting. [Figure 12A-5] 12A-1-12I show schematic diagrams of an example procedure for using the tool of FIG. 11A for double-sided imprinting. [Figure 12B-1]12A-1-12I show schematic diagrams of an example procedure for using the tool of FIG. 11A for double-sided imprinting. [Figure 12B-2] 12A-1-12I show schematic diagrams of an example procedure for using the tool of FIG. 11A for double-sided imprinting. [Figure 12B-3] 12A-1-12I show schematic diagrams of an example procedure for using the tool of FIG. 11A for double-sided imprinting. [Figure 12C] 12A-1-12I show schematic diagrams of an example procedure for using the tool of FIG. 11A for double-sided imprinting. [Figure 12D] 12A-1-12I show schematic diagrams of an example procedure for using the tool of FIG. 11A for double-sided imprinting. [Figure 12E] 12A-1-12I show schematic diagrams of an example procedure for using the tool of FIG. 11A for double-sided imprinting. [Figure 12F] 12A-1-12I show schematic diagrams of an example procedure for using the tool of FIG. 11A for double-sided imprinting. [Figure 12G] 12A-1-12I show schematic diagrams of an example procedure for using the tool of FIG. 11A for double-sided imprinting. [Figure 12H] 12A-1-12I show schematic diagrams of an example procedure for using the tool of FIG. 11A for double-sided imprinting. [Figure 12I] 12A-1-12I show schematic diagrams of an example procedure for using the tool of FIG. 11A for double-sided imprinting.

[0067] [Figure 13A] 13A-13F show schematic diagrams of example features of the tool of FIG. 11A for double-sided imprinting. [Figure 13B] 13A-13F show schematic diagrams of example features of the tool of FIG. 11A for double-sided imprinting. [Figure 13C]13A-13F show schematic diagrams of example features of the tool of FIG. 11A for double-sided imprinting. [Figure 13D] 13A-13F show schematic diagrams of example features of the tool of FIG. 11A for double-sided imprinting. [Figure 13E] 13A-13F show schematic diagrams of example features of the tool of FIG. 11A for double-sided imprinting. [Figure 13F] 13A-13F show schematic diagrams of example features of the tool of FIG. 11A for double-sided imprinting.

[0068] [Figure 14] FIG. 14 shows a schematic diagram of another exemplary tool for double-sided imprinting.

[0069] [Figure 15-1] 15A-15H show schematic diagrams of an exemplary procedure for using the tool of FIG. 14 for double-sided imprinting. [Figure 15-2] 15A-15H show schematic diagrams of an exemplary procedure for using the tool of FIG. 14 for double-sided imprinting. [Figure 15-3] 15A-15H show schematic diagrams of an exemplary procedure for using the tool of FIG. 14 for double-sided imprinting. [Figure 15-4] 15A-15H show schematic diagrams of an exemplary procedure for using the tool of FIG. 14 for double-sided imprinting.

[0070] [Figure 16] FIG. 16 is a flow diagram of an exemplary process for fabricating a double-sided imprint on a substrate.

[0071] [Figure 17] FIG. 17 is a flow diagram of another exemplary process for fabricating a double-sided imprint on a substrate.

[0072] [Figure 18]FIG. 18 is a flow diagram of a third exemplary process for fabricating a double-sided imprint on a substrate.

[0073] [Figure 19] FIG. 19 is a flow diagram of a fourth exemplary process for fabricating a double-sided imprint on a substrate. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0074] For double-sided imprinting, alignment of imprinted features from one side to another is critical in the manufacture of some devices. In some implementations, alignment of the top-side template to the pattern on the bottom side of the substrate requires finding reference marks on both the template and the substrate, and then using a high-resolution positioning system to align the template and substrate relative to each other. After alignment, the template can be carefully pressed against the substrate to ensure that no pockets of trapped air are created and that the detailed features of the template are completely filled. Once illumination light, e.g., ultraviolet (UV) light, cures the resist, e.g., UV-curable resist, between the template and substrate, the template can be separated and the patterns can stand on both sides of the substrate.

[0075] The imprinting process involves contacting a substrate with a UV curable resist with the template web as it moves under rollers. The rolling action causes the UV resist to fill the spaces in the template and push out all the air. At this point, the UV resist is cured and the template is separated from the substrate under the rollers as the web path bends and moves away from the linear motion of the substrate on the vacuum chuck.

[0076] When the template is carried by a flexible, moving web, it is difficult to determine the position of the template with a high degree of accuracy. The web can move a small amount side to side as it advances over rollers in the tool. The web can be advanced by rollers that are connected to motors. These rollers have diameter variations and rotary encoders have limited resolution. Because the web is also flexible, tension variations cause the web and template to stretch and move vertically.

[0077] In some implementations, the web is advanced into a zone where a template is available for imprinting on the substrate and a camera system is used to locate alignment marks on the template. Once the location of the reference marks is found, the template can be used to create the imprint on the substrate without moving the web. In this way, movement after locating the substrate can be eliminated, ensuring greater positional accuracy of the template and better alignment to the imprint on the opposite side of the substrate. In some implementations, the imprint features are transferred to the substrate without relying on advancement of the web over a leading roller.

[0078] The present disclosure describes methods, devices, and systems for double-sided imprinting that address the problems described above. Figures 1-4B show an example template chucking method. Figures 5A-5H show an example of locating reference marks on the template and substrate for side-to-side imprint alignment. Figures 6A-6B show an example squeegee roller for pushing the template into the resist along the substrate during imprinting. Figures 7A-7B show an example of a theta adjustment for correcting roller angle misalignment and web angle measurement. Figures 8-10 show an example implementation of double-sided imprinting. Figures 11A-13F show an example tool for aligned double-sided imprinting with associated procedures and configurations. Figures 14-15H show an example tool for simultaneous double-sided imprinting with associated procedures. Figures 16-19 show an example process for fabricating a double-sided imprint on a substrate, for example, using the devices, systems, or tools described above.

[0079] These techniques described in this disclosure can be applied to fabricate any suitable micro- or nano-structures or any double-sided patterned structures, such as diffraction gratings, on a single or both sides of any suitable substrate (e.g., rigid or flexible material). In one example, the techniques can be utilized to fabricate diffractive optical elements (DOEs) for eyepieces, as described in U.S. Patent Application No. 14 / 726,424, entitled "Methods and systems for generating virtual content display with a virtual or augmented reality apparatus," filed May 29, 2015, the contents of which are hereby incorporated by reference in their entirety. The DOEs can have one or more layers, each layer including an orthogonal pupil expansion (OPE) diffractive element and an exit pupil expansion (EPE) diffractive element. In some cases, the OPE diffractive element and the EPE diffractive element can be fabricated on opposite sides of a waveguide substrate. In some cases, the OPE and EPE diffractive elements can be fabricated on one side of a waveguide substrate, and other components can be fabricated on the other side of the waveguide substrate. In another example, the present techniques can be utilized to fabricate a diffraction grating on one side of a substrate with varying structures on the other side of the substrate, as illustrated in FIG. 7E of U.S. Provisional Patent Application No. 62 / 447,608, entitled "Manipulating optical phase variations in diffractive structures," filed Jan. 18, 2017, the contents of which are hereby incorporated by reference in their entirety. (Example of template chucking method) I. Direct Annular Template Chucking with Web Dome

[0080] When the template is carried by a flexible moving web, it is difficult to determine the position of the template with high accuracy. A flexible template (e.g., a coated resist template - CRT) can move a small amount side to side as the web advances over rollers in the imprinting tool. When the template is advanced by rollers connected to motors, motion errors accumulate because these rollers have variations in their diameter and rotary encoders have limited resolution. Since the web is also flexible, tension variations stretch the web and template and move them vertically. In some implementations, an annular ring grips the template with a vacuum, so the web can be moved with a set of precision stages to align it to a reference mark on the substrate while the web is guided to the contact point through optical feedback.

[0081] 1 shows an exemplary imprinting tool 100 with direct annular template chucking with a web dome. A web 102 is stretched against an annular ring vacuum chuck 104, which is located above the web 102 and between z-rollers 106a, 106b in the imprinting tool 100. The ring vacuum chuck 104 has a cavity 108 inside the vacuum region that may be covered and sealed with a glass window 110. The glass window 110 allows a vision system 112 to precisely locate reference marks on a template 120 on the web 102, a UV curing light 114 to cure a UV resist 116, and pressure or vacuum to be applied to the web 102 in the region inside the ring vacuum chuck 104.

[0082] When pressure is applied to the inner area of ​​the annular ring vacuum chuck 104, the web 102 with the template 120 can bend outward like a balloon, with the area in the center of the ring being pushed down slightly towards the substrate 118 on the stage 130, which can be moved vertically (e.g., along the Z direction) and horizontally (e.g., along the X direction). When the template 120 and substrate 118 come together for imprinting (either by moving the template 120 down or the substrate 118 up), the center portion of the template 120 can initially touch the substrate 118 within a small circular area, and as the template 120 and substrate 118 are brought closer together, the contact area will continue to increase as air is pushed out and the resistor fills in the details within the template 120. At this point, the resist 116 is hardened with light 114, the ring vacuum chuck 104 releases the template 120, and the stage 130 and web 102 are advanced together until separation occurs at the z-rollers 106a or 106b.

[0083] Holding a flexible template, e.g., template 120, with an annular ring vacuum chuck, e.g., ring vacuum chuck 104, provides several advantages. First, the technique fixes the template for precise positioning. Second, if the template is a transparent material, the technique allows a vision system to see through alignment marks on the substrate below to perform precision alignment. The technique also allows pressure to be applied to the back of the template, bending the template so that when contact occurs with the substrate, the contact point can be in the center and air can be forced out between the template and substrate. A transparent template allows a UV curing step to harden the features. For separation of the template from the features, the vacuum is released and the web with the substrate is driven forward, and separation occurs at the rollers as the path of the web moves away from the linear path of the substrate. (II. Indirect Template Chucking with Glass Dome)

[0084] FIG. 2 shows a schematic diagram of an exemplary imprinting tool 200 with indirect template chucking with a glass dome. The imprinting force can be applied using a separate pressure dome assembly 204 that can be lowered into the backside of the web 202 above the template 220. The glass dome 204 can include a thin piece of transparent glass 210 that takes on a dome shape when a closed volume 208 behind the glass 210 is pressurized. The glass backside allows for optical template reference mark location by a vision system 212 and UV curing by a UV light 214. Once the dome-shaped glass 204 is lowered into the backside of the web 202, friction between them can lock the web 202 in place. At this point, the vision system 212, e.g., a camera, can find the reference marks on the template 220 and on the substrate 218 below. The stage assembly 230 that holds the substrate can move the reference marks to align with the optical feedback, e.g., horizontally along the X direction.

[0085] After alignment, the substrate 218 is brought out from under the template 220, a UV-curable resist 216 is applied, and then the substrate 218 is moved back into alignment for imprinting. When the dome 204 and template 220 are moved into the substrate 218, for example vertically, the template 220 will first contact the substrate 218 at the center and a contact patch will grow outward, pushing out the air. At this point, the imprint can be cured with UV light, and then the dome 204 can be raised and separated from the backside of the flexible template 220. The web 202 can be advanced with the substrate 218 on the vacuum chuck 204, and the template 220 can be separated from the substrate 218 at the z-rollers 206a or 206b. (III. Template Vacuum Chucking and Air / Vacuum Bar Chucking)

[0086] FIG. 3A shows a schematic diagram of an exemplary template vacuum chucking 300. A web 302 is stretched along two z-rollers 306a, 306b. The web 302 can be vacuum chucked by vacuum chucks 308, 310 at certain locations around the template area including the template 320 to prevent the web 302 from slipping around the z-rollers 306a, 306b or to prevent tension fluctuations from inducing errors in the position of the web 302. As illustrated in FIG. 3A, the two vacuum chucks 308, 310 can be arranged in front of and behind the high-friction z-roller 306b, respectively. The vacuum chuck 308 is adjacent to but spaced from the template 320. The web 302 can be stopped by locking the high-friction z-rollers 306a and / or 306b with a brake 304 and maintaining tension with drive motors upstream and downstream of the imprinting zone. The vision system 312 can directly identify the location of the reference marks on the template 320 on the web 302. The UV curing light 314 can also directly cure the UV resist on the template 320.

[0087] FIG. 3B shows a schematic diagram of an exemplary air / vacuum bar chucking 350. An air bearing turn bar 354 is used in FIG. 3B instead of a leading z-roller, e.g., z-roller 406b in FIG. 3A. A web 352 is stretched along the air bearing turn bar 354 and z-roller 356. In some cases, the air bearing turn bar 354 can create a vacuum on its air pressure switch and act to crimp the web 352 after it is stopped in an area where the template reference mark for the template 370 can be precisely located. As discussed in more detail in FIG. 13B, the air bearing turn bar 354 can float the web 352 and does not impose any lateral or angular constraint on the web 352. IV. Glass Dome Template Backing Plate with Substrate Pressure Dome

[0088] The crucial technical challenge of imprinting both sides of a substrate by imprinting one side at a time is holding the substrate for imprinting without damaging the pattern on the back side. If the pattern on the back side comes into contact with the vacuum chuck or wafer handling end effector, damage can occur in three or more modes: the first damage mode can be scratching of the imprinted pattern, the second damage mode can occur if any residue falls onto the vacuum chuck that is transferred to the substrate, and the third damage mode can be that the vacuum chuck is somehow contaminated with uncured resist that is transferred to the substrate and cured as defects. In some cases, a double-sided process in which the substrate is gripped by a robot along the edges can eliminate these defect issues, but the robot can add complexity.

[0089] In some implementations, the vacuum chuck is created with a pocket to provide a cushioned area for the imprinted pattern, which can help mitigate the chafing problem, but may not prevent other failure modes.

[0090] FIG. 4A shows a schematic diagram of an exemplary alternating region 400 of pressure and vacuum. As shown, a substrate 402 is held by a vacuum chuck in two small regions 404a, 404b around the periphery of the substrate 402. An area 406 for imprinting is surrounded by the periphery at the center of the substrate 402. Optical reference marks 408 are around the periphery and outside the area 406. The substrate 402 has a tight array of vacuum and pressure zones 410 to minimize distortion of the substrate 402 while preventing the substrate 402 from touching the vacuum chuck. This wafer chuck can eliminate abrasion and particle contamination. In some cases, this wafer chuck has local elastic distortions while chucking under pressure and vacuum regions. The amplitude of distortions can be exacerbated by a reduction in substrate thickness. However, these distortion areas can be flattened during the imprinting process.

[0091] FIG. 4B shows a schematic diagram of an embodiment 450 of a glass dome template backing plate with a substrate pressure dome. The web 452 is stretched along two z-rollers 456a, 456b, which can be moved vertically up and down. The substrate 458, which is matched in mechanical bending properties of the glass dome 454, can be held by a vacuum chuck 460 on a stage 480 in an annular vacuum area along the edge. The center of the vacuum chuck 460 can have a deep recess so as not to touch any critical features or transfer any residue. After alignment of the substrate 458 and template 470, the glass dome 454 can press downwards, pressing the template 470 into the substrate 458, initially creating a small circular contact at the center, which can grow to the edge of the substrate 458 as full contact is achieved. Curing and separation can occur, and the web 452 can be peeled off the substrate 458 in a typical manner around the z-rollers 456a. (Example of Alignment Reference Marks and Imprinting Alignment)

[0092] Another crucial technical challenge of double-sided imprinting of a substrate is precisely locating the reference marks on the template and on the backside of the substrate.

[0093] 5A-5B show schematic diagrams of an embodiment 500, 530 of locating a reference mark on a template. A web 502 is stretched along two z-rollers 506a, 506b. As FIG. 5A shows, a reference mark 512, e.g., a diffraction pattern, on the template 510 is located with the laser light from the laser 504 from the opposite side of the web 502 when the protective layer is removed. A laser sensor 508 is positioned on a movable stage 520 and configured to detect the laser light 504 through the web 502. When the reference mark 512 on the template 510 is moved between the laser 504 and the laser sensor 508, the laser light will be diffracted or blocked by the reference mark 512, and as a result, the intensity of the laser light detected by the laser sensor 508 will be changed. Based on the change in the detected laser light intensity, the location of the reference mark 512 can be determined.

[0094] In some cases, as Figure 5B shows, the laser 504 can also be used to detect reference marks 514 on the edge of the template 510 when the template 510 is mounted on the edge of a vacuum chuck and looked up. The vacuum chuck can be an x-stage air bearing vacuum chuck, such as the air / vacuum bar vacuum chuck 354 of Figure 3B. A camera system can also be used to identify the location of the reference marks 512 or 514 from the top of the template 510 or mounted facing the vacuum chuck.

[0095] 5C-5D show schematic diagrams of examples 550, 570 of locating a reference mark on a substrate. A separate laser 554 (FIG. 5C) or camera system 572 (FIG. 5D) can find the reference mark 562 on the substrate 560 after the substrate 560 is acquired, for example, by a vacuum chuck stage. This camera system 572 or laser 554 can be pointed downward and fixed to chuck the substrate 560. The substrate 560 can be moved in x and y by the vacuum chuck stage to find the center of the reference mark 562.

[0096] If a camera system is used to look down at the reference marks 512 or 514 on the template 510, and a downward looking camera 572 is used to find the reference mark 562 on the substrate 560, it may be possible to place a separate reference target on the vacuum chuck stage that is visible and measurable by both cameras. Knowing the xy stage position of this reference mark in both cameras may allow a simple method for initially aligning both vision systems.

[0097] 5E-5F show schematic diagrams of examples 580, 585 of locating a reference mark on a template. Before the template 510 is moved for imprinting, the template 510 is positioned in front of the z-roller 506b at an angle to the horizontal. A laser 582 (FIG. 5E) or a camera system 586 (FIG. 5F) can be arranged in front of (or upstream of) the z-roller 506b and aligned with the template 510 at a similar angle to the horizontal. A first side imprint can be formed on a first side of the substrate 560, for example, by aligning with a reference mark on the substrate 560. The tilted laser 582 or tilted camera system 586 can identify the location of the fiducial reference mark 512 on the template 510 before the start of a second side imprint formed on a second, opposite side of the substrate 560, when the web 502 does not need to move. The fiducial reference mark 512 can be aligned with a reference mark 562 on the substrate 560 for the second side imprint using, for example, a laser 554 or a camera system 572 shown in Figures 5C and 5D. In this way, inaccurate template movements of the flexible template 510, for example a CRT, can be eliminated, thereby increasing the alignment accuracy (overlay) of the second side imprint relative to the first side imprint formed on the first side of the substrate 560.

[0098] 5G-5H show schematic diagrams of an embodiment 590 of side-to-side imprinting alignment with a vacuum chuck. The first imprint template 510a on the first web 502a can be tensioned to remove sagging, and then a set of cameras, including, for example, a camera 592, can be used to identify the location of the first fiducial mark 512a on the first imprint template 510a, optionally the second fiducial mark 512b on the second imprint template 510b of the second web 502b, and the fiducial mark 562 on the side of the substrate 560 in the same figure. A stage holding the substrate 560 can align the fiducial marks 512a, 512b, and 562. After alignment, a vacuum chuck 594 above the first web 502a can grip the first imprint template 510a from above, as illustrated in FIG. 5G. The vacuum chuck 594 can be connected to a precision movement mechanism that can move the first imprint template 510a to an imprint start position that is synchronized with the imprint start position of the substrate 560, as illustrated in Figure 5H. This eliminates inaccurate movement of the first imprint template 510a and allows side-to-side imprint alignment, e.g. a first imprint formed from the first imprint template 510a on a first side of the substrate 560 to be aligned with a second imprint formed from the second imprinted template 510b on a second, opposite side of the substrate 560. (Exemplary Squeegee Roller)

[0099] 6A shows a schematic diagram of an embodiment 600 of using squeegee rollers during imprinting. A web 602 is stretched along two z-rollers 606a, 606b. After the web 602 is stopped and reference marks on the template 610 and substrate 616 (not shown) are identified by a vision system 612, an additional roller 608 (called a squeegee roller) is lowered into the backside of the web 602, for example along the Z direction, and configured to push the template 610 into the resist 618 along the substrate 616 on the stage 620. The squeegee roller 608 traverses between the z-rollers 606a, 606b and may be able to push air out as the roller 608 moves back and forth along the X direction, which may help fill in the details of the template 610. The squeegee roller 608 can be shifted slightly, the resist 618 can be cured with UV light 614, and the template 610 can be separated from the substrate 616 at the z-roller 606a.

[0100] FIG. 6B shows a schematic diagram of another embodiment 650 of using squeegee rollers. A web 652 is stretched along two z-rollers 656a, 656b. After the web 652 is locked at the z-roller 656b, a camera can identify the location of a reference mark (or pattern) on the template 660, and the squeegee roller 658 can be parked near the locked z-roller 656b. The unlocked z-roller 656a can be lifted slightly offset along the Z-direction, while the adjacent drive roller, i.e., the squeegee roller 658, can be pulled along a portion of the web 652 along the X-direction to maintain tension as the web path is shortened. In some cases, a z-axis vacuum chuck can be on the substrate 666 to lift the substrate 666 until it touches the squeegee roller 658 and the locked z-roller 656b. The squeegee roller 658 can move away from the locked z-roller 656b, pushing the template 660 into the resist 668 on the substrate 666 and pushing air out. The squeegee roller 658 can stop after the template 660 is in full contact with the substrate 666 and the resist 668 is cured. After curing, the web 652 and substrate 666 can advance together and template separation can occur at the z-roller 656a. Exemplary Theta Adjustment and Web Angle Measurements

[0101] A unique way to correct angular misalignment in the theta-z direction by a small amount is to move one of the z rollers relative to each other along its axis. FIG. 7A shows a schematic diagram of an example 700 of implementing this method. The web 702 can move with the z rollers 706a, 706b due to high friction, wrap angle, and / or tension. In some cases, air bearing bushings can be used instead of roller bearings that allow low friction in rotation and axially. A push actuator (not shown) can push one end of the z roller shaft and a spring can push the other end to eliminate the rebound. This alignment can cause small waves in the web 702 if it is over-displaced, however, it can work well enough for small angles. Adjusting the position in this way can eliminate the need for a large, bulky and expensive rotary stage mounted as a single unit on either the x-stage or the rotary section or the web path and all of its support rollers.

[0102] Web angle change is a large component to web alignment errors when making double-sided imprinting. Figure 7B shows a schematic diagram of an exemplary method 750 for measuring the web angle to correct feed-forward imprinting alignment. The method 750 can, for example, directly measure the web angle immediately before each imprinting, and the substrate can be repositioned, for example, by a stage under the substrate chuck, based on the measured web angle prior to starting imprinting. For example, as illustrated in Figure 7B, two non-contact sensors 710a, 710b can be positioned upstream of the z-roller 706b on the edge of the web 702 and used together to measure the exact angle of the web 702. The sensors 710a, 710b are fixed and do not move with the web 702. (Example of double-sided imprinting) (I.1 step double-sided imprint, substrate nip feed)

[0103] 8 shows a schematic diagram of an exemplary system 800 for making double-sided imprints on a substrate. The system 800 is configured to use two webs 802a, 802b, one above and one below. The web 802a is stretched along two z-rollers 804a and 804b, and the web 802b is stretched along two z-rollers 804c and 804d. The webs 802a, 802b include separate templates 806a, 806b. The top and bottom templates 806a, 806b can be identified using a vision system, and precision adjustment axes can be distributed between the top and bottom webs such that the webs 802a, 802b can be aligned with each other.

[0104] In some cases, as Fig. 8 shows, the substrate 810 is coated with resist 808a and the template 806b is coated with resist 808b under the bottom side of the substrate 810 before the template 806b is rolled into the imprinting zone, for example along the X direction. In some cases, the substrate 810 can be coated with resist on both the top and bottom sides before being rolled into the imprinting zone. The loading robot can be configured to hold the substrate 810 on an edge and feed the substrate 810 into the nip between the rollers 804b, 804d as the webs 802a, 802b advance, while the top and bottom z rollers 804b, 804d push the resist 808a, 808b into the details of the templates 806a, 806b and remove air. Once the substrate 810 is in full contact with the templates 806a, 806b, the webs 802a, 802b and robot can be stopped and UV light can cure the resist 808a, 808b. In some implementations, the webs 802a, 802b and robot are reversed and the templates 806a, 806b are separated from the substrate 810. In some implementations, the webs 802a, 802b are advanced and pulled away from the rollers 804a, 804c so as to separate from the substrate 810. The substrate 810 can be held by another robot to the left of the rollers 804a, 804c. This process can improve imprinting throughput but may not accurately position the imprints. (II. One-step double-sided imprint using double glass domes)

[0105] FIG. 9 shows a schematic diagram of another exemplary system 900 for forming imprints on both sides of a substrate 950 at once. The system 900 is configured to combine the double-sided imprinting method described in FIG. 8 with each side imprinting using separate glass domes described in FIG. 2. The web 902 is stretched along two z-rollers 906a and 906b, and the web 952 is stretched along two z-rollers 956c and 956d. The webs 902, 952 include separate templates 920, 970. The system 900 can have, for example, top and bottom double template rolls 920, 970 separated by a few millimeters. The system 900 includes two top and bottom pressurized glass domes 904 and 954, vision alignment systems 912, 962, and precision adjustment axes (not shown) distributed between the system components for proper relative alignment of the top and bottom templates 920, 970 along the Z direction. The system 900 is also configured to dispense resist 930 onto the top and bottom surfaces of the substrate 950, or onto the template 920 and / or template 970 itself.

[0106] The imprinting sequence may be as follows: the webs 902 and 952 are advanced so that a new top template 920 and a new bottom template 970 are both brought into the imprinting zone. The vision systems 912 and 962 locate the reference marks on the templates 920, 970, and various adjustment axes align the top and bottom templates 920, 970. The glass pressure domes 904 and 954 are brought into contact with the webs 902, 952 on the top and bottom surfaces. There may be fine adjustment axes of the glass domes 904 or 954 that are configured to make slight corrections with respect to optimal template alignment after the glass domes 904 or 954 contact the webs 902 or 952. The resist 930 is applied to the top and bottom surfaces of the substrate 950. For example, a robot with a special thin end effector can present the substrate 950 between the top and bottom templates 920, 970 by gripping the substrate 950 on the edges. The top and bottom glass domes 904 and 954 can come together evenly such that as the pressure domes come together the z position of the substrate 950 is determined by the positions of the pressure domes 904 and 954. When the domes 904, 954 are completely flat and the templates 920, 970 are completely filled, the resist 930 is cured by the UV lamps 914. The pressure domes 904, 954 are then retracted from the top and bottom webs 902, 952. The webs 902, 952 and the robot can be reversed together and the templates 920 and 970 are peeled off the substrate 950 at the z rollers 906a, 956a.

[0107] The technique described above addresses the challenges of double-sided imprinting, i.e., all of the process requirements can be embodied in one tool architecture. The technique can facilitate UV curing and enable alignment, uniform force application, UV resist flow, nanofeature formation, and template and feature separation. III. Substrate on a Roll

[0108] It is desirable to use a suitable low cost substrate material that is flexible enough to be wound on a roll, with optical properties that can enable significant manufacturing cost reductions in large quantities. Most of the imprinting methods described above can be adapted to use substrates supplied in roll form, in particular the double glass dome imprinting process described in Figure 9. Handling of the substrate can be simpler than the edge gripping method.

[0109] FIG. 10 shows a schematic diagram of an exemplary system 1000 that uses a low-cost flexible substrate 1030 in roll format in conjunction with dual glass dome imprinting. The dual glass dome printing arrangement of the system 1000 is similar to the system 900 of FIG. 9. A first web 1002 is stretched along two z-rollers 1006a and 1006b from roller 1008a to roller 1008b. The web 1002 can be rotated from roller 1008b back to roller 1008a. The web 1002 includes a first template 1010 that includes imprinting features that are imprinted on the top side of the substrate 1030. A second web 1052 is stretched along two z-rollers 1056a and 1056b from roller 1058a to roller 1058b. The web 1052 can be rotated from roller 1058b back to roller 1058a. The second web 1052 includes a second template 1060 that includes imprinting features to be imprinted on the bottom side of the substrate 1030. The system 1000 can include two pressurized glass domes 1004 and 1054, top and bottom, vision alignment systems 1012, 1062, and precision adjustment axes (not shown) distributed among the system components for proper relative alignment of the top and bottom templates 1010, 1060 along the Z direction. The system 1000 can be configured to dispense resist, e.g., UV-curable resist, onto the top and bottom surfaces of the substrate 1030, or onto the template 1010 and / or template 1060 themselves.

[0110] The substrate 1030 is stretched from roller 1032 to roller 1034. In some cases, the substrate 1030 is a blank substrate that is rolled up on roller 1032 as illustrated in FIG. 10. In some cases, the roll of blank substrate is protected by a layer of film that is rolled up with the blank substrate to become the substrate 1030. Once the substrate 1030 enters the imprinting region of the system 1000, the protective cover film can be removed. The templates 1010 and 1060 can be brought into contact with the substrate 1030 using pressure domes 1004 and 1054, respectively. Air can be pushed out until the templates 1010 and 1060 are in full contact with the substrate 1030, and UV light 1014 can then cure the resist as the webs 1002, 1052 are secured in place. Thus, blank substrate 1030 becomes substrate 1040, with both sides imprinted with the corresponding features of templates 1010 and 1060. Domes 1004 and 1054 can be retracted from the backsides of templates 1010 and 1060, for example by a vacuum chuck, and separation of templates 1010, 1060 and substrate 1040 will occur as webs 1002, 1052 are advanced, where the path of substrate 1030 diverges from the paths of templates 1010, 1060. At this point, the imprinted features are fully formed on substrate 1040.

[0111] In some implementations, as FIG. 10 illustrates, the substrate 1040 is wound with a first layer of protective film 1070 on the back side and a second layer of protective film (not shown) on the front side on the substrate 1042 that is wound on a roller 1034. The first layer of protective film 1070 can be stretched onto the back side of the substrate 1040 from roller 1072a to z-roller 1072b. The second layer of protective film can be stretched onto the front side of the substrate 1040 from another roller (not shown) to another z-roller (not shown). A squeegee roller 1036, for example, squeegee roller 608 in FIG. 6A, can be used to press the protective film onto the substrate 1040. In some cases, another process can be applied to the imprinted substrate 1040 before the protective film is wound or the substrate 1042 with features imprinted on both sides can be cut from the roll.

[0112] The techniques described above allow single-sided patterning of substrates and patterning on substrates with tight front-to-back alignment to be performed by keeping the substrates in roll format and simplifying material handling. By supplying low cost substrates in roll format, the techniques can be economical to imprint patterns on both sides of the substrate and keep the substrate in this format until individual components need to be singulated. (Example Tool for Coordinated Double-Sided Imprint)

[0113] Nanofabrication equipment typically forms features on one side at a time. If a single-sided process is used to create features on both sides, it essentially takes twice the time and two pieces of equipment, but may still have an alignment step to align the substrate features to the template features. Also, the imprinted features after formation are fragile and susceptible to handling damage. These types of substrates are typically handled with backside contact, but touching the backside of the substrate in cases where there are features on both sides can damage these features.

[0114] 11A shows a schematic diagram of an exemplary tool 1100 for aligned double-sided imprinting on a substrate. The tool is configured to fabricate imprinted features on both sides of a substrate whose positions are precisely controlled relative to each other. The front and back templates can be optically pre-aligned to each other before imprinting and features on both sides can be created simultaneously. The tool is also configured to handle the substrate without damaging the imprinted features on both sides of the substrate.

[0115] In some implementations, the imprinting tool 1100 includes three zones: (a) substrate input, (b) imprint engine, and (c) imprinted substrate output. Two webs 1102a, 1102b are stretched through z-rollers 1104a, 1104c to z-rollers 1104b, 1104d, respectively. The webs 1102a, 1102b have individual flexible templates, e.g., CRTs, that are stretched together in an area where the substrate 1112 is inserted. The substrate 1112 is a wafer substrate and can be taken from a substrate container 1110 that stores several blank substrates. The robot 1106 is configured to take the substrate 1112 from the container 1110 via the robot holder 1108 and insert it into the area between the flexible templates.

[0116] Before the substrate 1112 is inserted, the reference marks on the templates of each web 1102a, 1102b can be optically aligned with one another using a camera system and actuation that allows for relative positioning of the webs 1102a, 1102b. As discussed in more detail below, the tool 1100 of FIG. 11A can include a crimping system for crimping the two webs 1102a and 1102b. After the reference marks are aligned, the webs 1102a, 1102b can be crimped together to eliminate relative motion of the templates. The webs 1102a, 1102b can be reversed to allow for the insertion of the substrate 1112, UV-curable resist from resist injection heads 1114a, 1114b can be applied to the templates, and the templates can then be realigned together with the substrate and resist between them. As the substrate 1112 progresses through the process zones in zone (b), a UV light source 1116 can cure the resist. After curing, the compression system can be decompressed to separate the webs 1102a, 1102b and allow the imprinted substrate 1118 to pass, as illustrated in Figure 12H below. The fully imprinted substrate 1118 from the substrate 1112 can then exit and be picked up by another robot holder 1120 of another robot 1122 and stored in an imprinted substrate container 1124. The imprinted substrates 1118 in the container 1124 can be stored in soft cushioning and separated from one another.

[0117] FIG. 11B shows a schematic diagram of an exemplary tool 1150 for aligned double-sided imprinting on a substrate. Compared to the tool 1100 of FIG. 11A, the tool 1150 does not include unloading automation with a robot 1122 and a container 1124 in zone (c). Instead, the imprinted substrate 1118 can be returned to zone (a) and stored in the container 1110. In this way, the tool 1150 can eliminate unloading automation for the imprinted substrate 1118 and combine unloading automation with substrate loading automation. Similar to the tool 1100, the tool 1150 can also include a crimping system with a vacuum chuck 1208 for the web 1102a and a clamp 1210 for the web 1102b. After the reference marks on the web 1102a are aligned with the reference marks on the web 1102b, the webs 1102a, 1102b can be crimped together to each other by the crimping system to eliminate relative motion of the templates.

[0118] In an exemplary processing sequence, the substrate 1112 is lowered into the top between the two templates on the webs 1102a and 1102b for double-sided imprinting. After imprinting is completed and fully cured with the UV light source 1116, the z-rollers 1104a and 1104c can be rotated back so that the fully imprinted substrate 1118 is retrieved from the top by the same robot handler 1108 and robot 1106. In this way, the vacuum chuck 1208 and clamps 1210 can keep the templates aligned without having to be de-pressed to allow the imprinted substrate 1118 to exit from the bottom. Thus, the configuration (and processing sequence) of the tool 1150 can allow template alignment to be maintained for each sequential substrate, resulting in a significant reduction in process time as the time-consuming alignment process is performed only once on each set of templates.

[0119] 12A-1-12I show schematic diagrams of example operation sequences for the imprinting tool 1100 of FIG. 11A. For illustration purposes only, the operation sequences show the concept that the substrate progresses vertically from top to bottom. Other configurations can also be implemented, for example, a tool that is inverted so that the substrate can progress from bottom to top, or even horizontally. It is also noted that one or more of the operation sequences shown in FIG. 12A-1-12I can also be used for the imprinting tool 1150 of FIG. 11B.

[0120] 12A-1-12A-5 show the alignment of the reference marks 1204a, 1204b, 1204c, 1204d on the templates 1214a, 1214b of the webs 1102a, 1102b. The imprinting tool 1100 can include a crimping system including a vacuum chuck 1208 for the web 1102a and a clamp 1210 for the web 1102b. The vacuum chuck 1208 can be the vacuum chuck 308 or 310 of FIG. 3A. The vacuum chuck 1208 is positioned on a linear guide 1207 along a linear axis (or rail) 1206. The imprinting tool 1100 can also include a pair of nip rollers 1212a, 1212b that are retractable and can be moved slightly out of alignment with the webs 1102a, 1102b during imprinting. As discussed in more detail in FIG. 13F, the nip rollers 1212a, 1212b can be moved closer to one another to facilitate unloading the imprinted substrate 1118.

[0121] FIG. 12A-3 shows an exemplary template 1214a on the web 1102a. The template 1214a includes a plurality of features 1215 arranged within an area. In a particular embodiment, the substrate 1112 to be imprinted is a wafer, and the area can have a shape and size similar to that of the wafer. For example, the area can have a diameter D of, for example, about 200 mm. The template 1214a has two reference marks (or alignment marks) 1204a, 1204b designed to be aligned with the leading and trailing edges of the substrate 1112 during imprinting. Similarly, the template 1214b on the web 1102b also has two reference marks 1204c, 1204d similarly designed to be aligned with the leading and trailing edges of the substrate 1112 during imprinting. Therefore, reference mark 1204a must match reference mark 1204c, and reference mark 1204b must match reference mark 1204d so that the features on templates 1214a, 1214b are aligned with substrate 1112 and can be imprinted on both sides of substrate 1112.

[0122] A first alignment camera 1202a can be used to align the reference marks 1204a, 1204c on a first end of the templates 1214a, 1214b. A second alignment camera 1202b can be used to align the reference marks 1204b, 1204d on a second end of the templates 1214a, 1214b. The top schematic diagram of FIG. 12A-4 shows a misalignment between the templates 1214a, 1214b, where the reference marks 1204a and 1204c do not align with each other, and the reference marks 1204b and 1204d do not align with each other. Templates 1214a, 1214b can be adjusted in the x, y, and / or theta directions until the reference marks on templates 1214a, 1214b overlap with each other, e.g., 1204a with 1204c and 1204b with 1204d, as shown in the bottom schematic of FIG. 12A-4. In some cases, the theta adjustment for templates 1214b, 1214b can be implemented by adjusting at least one of the z rollers relative to each other along its axis, as illustrated in FIG. 7. In some cases, vacuum chuck 1208 first chucks onto web 1102a and adjusts the position of web 1102a in the x, y, and / or theta directions. While FIG. 12A-2 shows a bottom view of FIG. 12A-1 before adjustment, FIG. 12A-5 shows a bottom view of FIG. 12A-1 with a theta adjustment, in which the clamp 1210 is also rotated and the linear guide 1207 moves up along the linear axis 1206 on one end of the clamp 1210 and down on the other end of the clamp 1210.

[0123] The templates 1214a, 1214b, e.g., CRTs, can be adjusted in the X, Y, and theta directions. As illustrated in FIG. 12A-4, the X direction indicates the CRT advance direction and the Y direction traverses the width of the CRT. The camera systems 1202a and 1202b can view or view the CRT reference marks 1204a, 1204b, 1204c, 1204d and use the reference marks as feedback for relative positioning. The relative position of the webs 1102a, 1102b in the X direction can be controlled by advancing one of the webs on one side relative to the other of the webs using web drive rollers or can be moved through a vacuum chuck 1208 using linear guides or actuators 1207. The air turn bars 1104a-1104d allow the webs to slide in the X, Y, and theta directions with minimal friction, thus allowing for precise relative correction and aligning and placing the reference marks. The roller assembly 1300 can move in the Y direction to provide relative motion, as shown in Figure 13A, and a linear actuator 1207 can be mounted in the vacuum chuck 1208 to control the web in the Y direction. Theta adjustment can be accomplished by differential motion of the linear actuator 1207, which transmits motion through the vacuum chuck 1208.

[0124] After the reference marks 1204a, 1204b on the web 1102a are aligned with the reference marks 1204c, 1204d on the web 1102b, the webs 1102a, 1102b can be crimped together by a crimping system, for example, a vacuum chuck 1208 and a clamp 1210, to eliminate relative motion of the templates 1214a, 1214b. The crimping system can be positioned downstream of the leading reference marks 1204a, 1204c. Figures 12B-1-12B-3 show schematic diagrams of a configuration for crimping the webs 1102a, 1102b.

[0125] FIG. 12B-3 is a cross-sectional view of FIG. 12B-2 showing the crimping configuration. The vacuum chuck 1208 is supported by a pair of crimping actuators (and guides) 1218 for counterbalancing, which are further supported by a crimping bar 1210 with a rubber pad 1222 on top. A linear guide 1207 is connected on one end to the vacuum chuck 1208 via a connector 1209 and on the other end to a linear rail 1206 which is further connected to a machine frame 1220. The crimping configuration is configured such that the crimped webs 1102a, 1102b cannot have relative motion at or near the clamp 1210. The force difference can be minimized or eliminated so that the templates 1214a, 1214b (e.g., CRT) can have good alignment in an area large enough to encompass the substrate. The vertical linear rail 1206 is configured to pull and guide the templates 1214a, 1214b along a precision path at a constant velocity.

[0126] 12C-12D show schematic diagrams of an example of dispensing UV resist 1224 onto templates 1214a, 1214b. Webs 1102a, 1120b are moved back upward to expose templates 1214a, 1214b to resist injection heads 1114a, 1114b. A compression system, including vacuum chucks 1208 and clamps 1210, is moved together with webs 1102a, 1102b. Once reference marks 1204c, 1204d have passed back past resist injection heads 1114a, 1114b, resist injection heads 1114a, 1114b can begin dispensing UV resist 1224 onto templates 1214a, 1214b. When the reference marks 1204a, 1204b reach the resist injector heads 1114a, 1114b, the dispensing of the UV resist 1224 on the templates 1214a, 1214b is completed and the reverse motion is also completed. During the movement, tension is matched on both templates 1214a, 1214b.

[0127] After dispensing of the UV resist 1224 is completed, the webs 1102a, 1102b are advanced downward. At some point, as shown in FIGURE 12E, the substrate 1112 is inserted into the gap between the templates 1214a, 1214b. The gap is closed when the substrate 1112 and the UV resist 1224 are all moved downward between the webs 1102a, 1102b, as illustrated in FIGURE 12F. The compression system is also moved downward with the compressed webs 1102a, 1102b.

[0128] As the substrate 1112 and templates 1214a, 1214b with UV resist 1224 progress through process zone (b), as shown in FIG. 12G, the UV source 1116 cures the UV resist 1224 on the substrate 1112 resulting in a fully imprinted substrate 1118 with features on both sides. As shown in FIG. 12H, the fully imprinted substrate 1118 is pulled down to exit process zone (b) and the vacuum chuck 1208 and clamps 1210 are decompressed to separate the webs 1102a, 1102b. The imprinted substrate 1118 can then be moved out and picked up by the robot holder 1120 of the robot 1122 and stored in an imprinted substrate container 1124.

[0129] The tool 1100 can then be reset to imprint the next substrate 1112, as illustrated in Figure 12I. The resetting step can include separating the nip rollers 1212a, 1212b, retracting the linear guide 1207, tensioning the webs 1102a, 1102b, advancing the webs 1102a, 1102b, finding the reference marks on the templates 1214a, 1214b, diffusing the air turns, transferring the imprinted substrate 1118 (e.g., into the container 1124), and preparing the blank substrate 1112.

[0130] The present imprinting tool 1100 employs a vertical configuration in which the resist injection head can dispense UV resist in a symmetric and horizontal orientation, which also provides symmetric gravity, diffusion and separation, and particle isolation imprinting chambers, allowing for easier and more reliable delivery of ultra-thin substrates.

[0131] 13A-13F show schematic diagrams of example feature configurations of the tool 1100 of FIGs. 11A-12I for double-sided imprinting. It should also be noted that one or more of the feature configurations shown in FIGs. 13A-13E may also be used in the imprinting tool 1150 of FIG. 11B.

[0132] 13A shows a schematic diagram of an example configuration 1300 for a web path. A web 1102a can be fed from a feed roller 1302a and advanced in a clockwise direction through driver rollers 1304a, 1306a, z-rollers 1104a, 1104b, and driver rollers 1308a, 1310a to roller 1312a, while rollers 1306a and 1308a rotate in a counterclockwise direction. In some cases, the web 1102a from the feed roller 1302a includes a protective film. The driver roller 1304a can rotate in a clockwise direction and roller 1306a can rotate in a counterclockwise direction to remove the protective film from the web 1102a so that the template 1214a on the web 1102a is exposed. Similarly, web 1102b can be fed from feed roller 1302b and advanced in a counterclockwise direction through driver rollers 1304b, 1306b, z-rollers 1104c, 1104d, and driver rollers 1308b, 1310b to roller 1312b, while rollers 1306b and 1308b rotate in a clockwise direction. In some cases, web 1102b from feed roller 1302b includes a protective film. Driver roller 1304b can rotate in a counterclockwise direction and roller 1306b can rotate in a clockwise direction to remove the protective film from web 1102b such that template 1214b on web 1102b is exposed. In some cases, driver roller 1306b is a separate nip roller and is driven by driver roller 1306b'.

[0133] In some implementations, the configuration 1300 includes tension sensors 1314a, 1314b coupled to the z-rollers 1104b, 1104d and configured to measure tension in the webs 1102a, 1102b, respectively.

[0134] In some implementations, the z-rollers 1104a, 1104b, 1104c, 1104d are rollers with low friction. In some implementations, the z-rollers 1104a, 1104b, 1104c, 1104d are air turn rollers. As illustrated in FIG. 13B, the air turn roller 1104a can float the web 1102a through the air 1315 and does not impose lateral or angular constraints on the web 1104a. In some implementations, the air turn roller 1104a includes a central shaft 1320 and a cover 1318 made of a porous material supported by the central shaft 1320. There is an empty space between the central shaft 1320 and the cover 1318. Air pressure 1315 can be forced onto the space through inlet 1316, venting from cover 1318 such that a plenum of air 1315 is created between the initial position of cover 1318 and the current position of cover 1318, supporting cover 1318. Air turn rollers offer several advantages: 1) when typical z-rollers are used, small amounts of misalignment or theta offset can cause lateral stress and displace top-bottom pattern alignment; 2) there is a low risk of particle transfer between the z-roller and the web; 3) template float around the air turn can cause large particles to affect the smaller imprint area; 4) a tilted web may not track straight across the roller; and 5) the air turn may not resist motion in the linear axis 1206. FIG. 13C shows an implementation of FIG. 12A-5 where z-rollers 1104a, 1104b are air turn rollers.

[0135] Figure 13D shows a schematic diagram of an example configuration 1330 for an imprinting process. The tool 1100 includes a chamber 1332 configured to isolate an imprint engine process zone, e.g., zone (b) of Figure 11A, from the outside environment. The chamber 1332 can be controlled to have a constant temperature, e.g., 25°C, and / or level of cleanliness for imprinting.

[0136] 13E shows a schematic diagram of an exemplary substrate loading configuration 1350. The web 1102a can be pulled back, e.g., moved in reverse, for example, by rotating the rollers 1302a, 1304a, 1306a, 1104a, 1104b in a counterclockwise direction and wrapping over the roller 1306a. Similarly, the web 1102b can be pulled back, e.g., moved in reverse, by rotating the rollers 1302b, 1304b, 1306b and the rollers 1104c, 1104d in a clockwise direction and wrapping over the roller 1306b. The robot 1106 is configured to take the blank substrate 1112 from the container 1110 via the robot holder 1108 and insert it into the area between the flexible templates. The substrate 1112 can be a wafer substrate and the container 1110 can be a wafer container 1110′.

[0137] 13F shows a schematic diagram of an exemplary substrate unloading configuration 1370. By rotating rollers 1104b, 1308a, 1310a, 1312a, web 1102a can be pulled downward, e.g., advanced in a clockwise direction, to wrap onto roller 1312a. Similarly, web 1102b can be pulled downward, e.g., advanced in a counterclockwise direction, to wrap onto roller 1312b by rotating rollers 1104d, 1308b, 1310b, 1312b. When webs 1102a, 1102b are pulled downward, the crimping system releases and webs 1102a, 1102b are separated. After the fully imprinted substrate 1118 passes the position of the nip rollers 1212a, 1212b, the nip rollers 1212a, 1212b may approach each other to hold the webs 1102a, 1102b tightly. The fully imprinted substrate 1118 can then exit and be picked up by the robot holder 1120 of the robot 1122 and stored in an imprinted substrate container 1124. The substrate 1112 may be a wafer substrate and the container 1124 may be a wafer container 1124' for storing the double sided imprinted substrate 1118.

[0138] It should be noted that substrates of different shapes and sizes can be imprinted through this double-sided process equipment, other than the round substrate shown in the figure. Higher part throughput can be achieved when larger substrates that can be cut into more parts are run. Also, the width of the CRT is flexible, and a wider web can imprint larger substrates, leading to higher part throughput. (Exemplary scheme for simultaneous double-sided imprinting)

[0139] 14 shows a schematic diagram of another exemplary tool 1400 for double-sided imprinting on a substrate, e.g., a wafer substrate. For illustration purposes only, the substrate proceeds horizontally from right to left. Other configurations, e.g., the tool being inverted so that the substrate may proceed from left to right, or even vertically, can also be implemented.

[0140] A bottom web 1402a is stretched along two z-rollers 1404a, 1404b. The web 1402a includes a template 1406a, e.g., a CRT. The template 1406a may include a lattice feature as illustrated in FIG. 14. The template 1406a is configured with pre-patterned through holes so that a vacuum chuck 1416 below the template 1406a can gently hold the substrate 1414, e.g., a wafer, with a vacuum when the substrate 1414 is released by an upper loading equipment front end module (EFEM) 1408a. The vacuum chuck 1416 may be movable with the template 1406a. The top-loading EFEM 1408a can be positioned between a pair of dispenser heads 1410a, 1410b such that a first dispenser head 1410a can dispense resist onto the grating features of the template 1406a before the substrate 1414 is placed on the template 1406a, and a second dispenser head 1410b can dispense resist onto the substrate 1414 after the substrate 1414 is held on the template 1406a by a vacuum chuck 1416.

[0141] Another top web 1402b is stretched along two z-rollers 1404c, 1404d. The web 1402b includes a template 1406b (e.g., CRT), which may include features, such as grating features or other features. A UV light source 1412 can be positioned above the template 1406b. A second dispenser head 1410b can be arranged in front of the z-roller 1404c such that the second dispenser head 1410b already dispenses resist onto the top of the substrate 1414 when the substrate 1414 is moved under the template 1406b. The tool 1400 also includes another top-loading EFEM 1408b positioned adjacent to the z-roller 1404b. As discussed in more detail below, the top-loading EFEM 1408b is configured to take the substrate 1414 with the imprint from the template 1406a.

[0142] 15A-15H show schematic diagrams of an exemplary procedure for using the tool of FIG. 14 for double-sided imprinting.

[0143] FIG. 15A shows a schematic diagram of dispensing resist 1504a onto the bottom template 1406a. The first dispenser head 1410a can start dispensing resist 1504a after the alignment mark 1502a has passed the first dispenser head 1410a, such that the resist 1504a falls onto the feature of the template 1406a after the alignment mark 1502a, e.g., to the right of the alignment mark 1502a. After a quantity of resist 1504a has been dropped onto the feature of the template 1406a, the web 1402a can stop moving and wait for a period of time until the resist 1504a spreads over the feature of the template 1406a, as shown in FIG. 15B. In some embodiments, the template 1406a includes a grating feature configured to allow the resist to fall and spread precisely, e.g., evenly, and push out air, so that the resist 1504a fills the details within the template 1406a. The grating period of the grating features can be from tens of nanometers (nm) to tens of micrometers (μm).

[0144] After the resist 1504a has spread over the features of the template 1406a, the web 1402a can be moved again. As the resist 1504a moves under the top-loading EFEM 1408a, the web 1402a can be stopped and the substrate 1414 can be loaded onto the resist 1504a by the top-loading EFEM 1408a and held by the vacuum chuck 1416, as shown in FIG. 15C. Thus, the bottom surface of the substrate 1414 is in contact with the resist 1504a.

[0145] The web 1402a can then be moved again. When the substrate 1414 arrives under the second dispenser head 1410b, the second dispenser head 1410b begins to dispense the resist 1504b onto the top surface of the substrate 1414, as shown in FIG. 15D. In some cases, the web 1402a can stop waiting until the resist 1504b spreads on the top surface of the substrate 1414. In some cases, the resist 1504b spreads on the top surface of the substrate 1414 while the web 1402a continues to be moved. The tool 1400 can be configured such that the distance between the second dispense head 1410b and the z-roller 1404c is long enough for the resist 1540b to spread precisely on the top surface of the substrate 1414.

[0146] When the substrate 1414 with resist 1504a on the bottom surface and resist 1504b on the top surface is moved under the template 1406b, the features on the template 1406b begin to contact the resist 1504b, which fills the features on the template 1406b. Also, when the alignment mark 1502a is moved to be aligned with another alignment mark 1502b on the template 1406b, for example via a camera system, the top web 1402b can begin to be moved at the same speed as the bottom web 1402a. Also, the distance between the top template 1406b and the bottom template 1406a can be configured or controlled to allow the resist 1504b to fill into the features of the template 1406a, but the features do not contact the top surface of the substrate 1414. FIG. 15E shows a schematic diagram of a substrate 1414 with double-sided imprinting, eg, top resist 1504b in contact with top template 1406b and bottom resist 1504a in contact with bottom template 1406a.

[0147] As the substrate 1414 with the top resist 1504b and bottom resist 1504a and the templates 1406b and 1406a are moved under the UV light source 1412, the UV light source 1412 can be turned on to harden the resist 1504a and 1504b so that features on the templates 1406b and 1406a can be imprinted onto the resist on the top and bottom surfaces of the substrate 1414. The substrate 1414 with the imprinted resist is noted as the imprinted substrate 1414'.

[0148] After the resist 1504a, 1504b is cured on the substrate 1414, the top web 1402b is pulled upwardly around the z roller 1404d such that the template 1406b is separated from the imprinted substrate 1414', as illustrated in Figure 15F. To accomplish this, the roller 1404b can be positioned with a distance from the z roller 1404d.

[0149] The web 1402a is further moved underneath the top-loading EFEM 1408b. The vacuum chuck 1416 can release the substrate 1414' and the top-loading EFEM 1408b can take the imprinted substrate 1414' as illustrated in Figure 15G. The top-loading EFEM 1408b holding the imprinted substrate 1414' can be moved forward, for example to the left of the z-rollers 1404b, such that the imprinted substrate 1414' is separated from the bottom template 1406a as illustrated in Figure 15H.

[0150] Using the tool 1400 for double-sided imprinting as described above can provide several advantages. First, no substrate alignment is required. Second, alignment is implemented from the top template to the bottom template to eliminate imprint-related difficulties. Third, the bottom template can have pre-patterned through-holes to enable gentle vacuum retention of the substrate and ensure that the substrate is held during separation from the top template. Fourth, the tool can enable a gentle separation scheme with low separation forces that may avoid high separation forces that cause substrate loss or separation failure in both top and bottom imprints. Fifth, the bottom template has grating features configured to enable resist diffusion on the bottom template and eliminate fill concerns of the bottom imprint. Exemplary Double-Sided Imprinting Process

[0151] 16 is a flow diagram of an exemplary process 1600 for fabricating a double-sided imprint on a substrate. The process 1600 can be performed by the devices, systems, and / or tools described above, such as the imprinting tool 1100 of FIGS. 11-13F.

[0152] A first web is stretched along a first roller and a second web is stretched along a second roller (1602). The first web includes a first template including a first imprinting feature, e.g., a grating feature. The second web includes a second template including a second imprinting feature, e.g., a grating feature.

[0153] In some implementations, the first roller includes two first z rollers arranged vertically, and the second roller includes two second z rollers arranged vertically. The first z rollers can be positioned opposite the second z rollers with a distance. The first web can be stretched along the first z rollers in a counterclockwise direction, and the second web can be stretched along the second z rollers in a clockwise direction.

[0154] In some embodiments, the first roller includes at least one air turn roller configured to float the first web by air pressure. The air turn roller can be roller 1104a of FIG. 13A-13B. The second roller can also include at least one air turn roller configured to float the second web by air pressure. In some embodiments, the first roller includes at least one air turn roller configured to chuck the first web by vacuum, such as air bearing turn bar 354 of FIG. 3B.

[0155] The reference marks on the first and second webs are aligned (1604). A camera system (e.g., alignment cameras 1202a, 1202b in FIG. 12A-1) or a laser system (e.g., laser 504 and sensor 508 in FIG. 5A) can be used to locate (or detect) the reference marks on the first and second webs for alignment. The alignment system can be used to align the reference marks on the first and second webs such that the first and second templates are aligned with each other, e.g., a first imprinting feature is aligned with a second imprinting feature.

[0156] In some examples, aligning the reference marks on the first web and the second web includes aligning a first reference mark on the first web with a second reference mark on the second web and aligning a third reference mark on the first web with a fourth reference mark on the second web. The first and third reference marks can define an area in which the substrate is configured to be imprinted with the first template. The second and fourth reference marks can define an area in which the substrate is configured to be imprinted with the second template.

[0157] In some implementations, aligning the reference marks on the first web and the second web includes moving a z roller of the first roller in at least one of the x, y, or theta directions, as discussed above in Figures 12A-1-12A-5.

[0158] In some implementations, after the aligning step, the first and second webs are crimped at a location adjacent to the reference mark such that the crimped first and second webs are moved with the first and second templates aligned with each other. For example, as illustrated in FIG. 12B-1, the crimping location is downstream of the first reference mark.

[0159] The first web and the second web can be crimped together by a crimping system. The crimping system can include a chuck and a clamp. The chuck can be a vacuum chuck, such as vacuum chuck 1208 of FIG. 12A-1, configured to chuck onto the first web with a vacuum. The clamp can be clamp 1210 of FIG. 12A-1. The chuck can be actuated to chuck with the clamp such that the chuck is on one web and the clamp is on the second web.

[0160] In some cases, the chuck is configured to be movable along a rail parallel to an axis defined by the first roller, and the chuck and clamp are moved with the first and second webs after crimping. As illustrated in FIG. 12B-3, the chuck can be positioned on a pair of guides, each of which is movable on a separate rail connected to the frame. Aligning the reference marks on the first and second webs can include adjusting the relative position of the guides on the separate rails in at least one of the x, y, or theta directions. A tension sensor can be coupled to one of the first rollers to measure the tension of the first web. Another tension sensor can be coupled to one of the second rollers to measure the tension of the second web.

[0161] In some implementations, a chamber is used to enclose at least the first template and the second template. The chamber can be chamber 1332 of FIG. 13D. The controller can be configured to control the temperature and / or cleanliness of the chamber.

[0162] The first web is stretched in a first direction along a first roller to expose the first template to a first dispenser, and the second web is stretched in a second direction along a second roller to expose the second template to a second dispenser (1606). The first template can be stretched so that it is horizontal and underneath the first dispenser. The second template can be stretched so that it is horizontal and underneath the second dispenser.

[0163] A first dispenser dispenses a first resist onto the first template and a second dispenser dispenses a second resist onto the second template (1608). The first dispenser can dispense the first resist while the first template is passing through the first dispenser. The second dispenser can dispense the second resist while the second template is passing through the second dispenser.

[0164] When the first template is completely covered with the first resist and the second template is completely covered with the second resist, the first web and the second web are stretched in reverse (1610) so that the first template with the first resist and the second template with the second resist face each other. For example, the first web can be stretched upward in a counterclockwise direction to expose the first template for the resist, and the first web can then be stretched downward in a clockwise direction to pull the first template down. Similarly, the second web can be stretched upward in a clockwise direction to expose the second template for the resist, and the second web can then be stretched downward in a counterclockwise direction to pull the second template down.

[0165] A substrate is inserted (1612) between the first template with the first resist and the second template with the second resist. The substrate can be a rigid substrate, e.g., a wafer substrate such as a silicon wafer. The robot can be controlled to grip the edge of the substrate and feed the substrate into the gap between the first template and the second template. In some implementations, the first roller and the second roller are arranged such that after the inserting step, the substrate is moved together with the first template and the second template, the first resist is pressed, e.g., by one of the first rollers, onto a first side of the substrate and filled into the first imprinting features on the first template, and the second resist is pressed, e.g., by one of the second rollers, onto a second side of the substrate and filled into the second imprinting features on the second template.

[0166] In some implementations, the first squeegee roller is moved over the first web to press the first template into the first resist such that the first resist fills into the first imprinting features on the first template, and the second squeegee roller is moved over the second web to press the second template into the second resist such that the second resist fills into the second imprinting features on the second template. The first squeegee roller and the second squeegee roller can be positioned opposite each other while the first squeegee and the second squeegee are moving together. The first squeegee roller or the second squeegee roller can be squeegee roller 608 of FIG. 6A.

[0167] As the substrate and the first and second templates enter the imprinting zone, a light source, e.g., a UV light source, can irradiate and harden the first and second resists such that the hardened first resist has a first imprinted feature corresponding to the first imprinted feature on the first template on a first side of the substrate, and the hardened second resist has a second imprinted feature corresponding to the second imprinted feature on the second template on a second side of the substrate (1614). In such a way, the substrate is imprinted with double-sided imprinted features.

[0168] In some implementations, after curing, the first web and the second web are de-pressed to allow the substrate with the cured first resist and second resist to pass through the gap between the first web and the second web.

[0169] The double-sided imprinted substrate is unloaded 1616. The substrate can be unloaded by another robot and stored in a container, for example container 1124 in Figure 11A.

[0170] 17 is a flow diagram of another exemplary process 1700 for fabricating a double-sided imprint on a substrate. The process 1700 can be performed by the devices, systems, and / or tools described above, such as the imprinting tool 1400 of FIGS. 14-15H.

[0171] A first web is stretched (1702) along a first roller. The first web includes a first template having a first imprinting feature, e.g., a lattice feature. The first roller can include two z-rollers arranged in a horizontal direction and can be stretched from right to left. In some implementations, the first roller includes at least one air turn roller configured to float the first web by air pressure. The first roller can include at least one air turn roller configured to chuck the first web by vacuum.

[0172] A first resist is dispensed onto the first template (1704). The first dispenser can begin dispensing the first resist onto the first template as the beginning of the first template moves under the first dispenser and end as the end of the first template moves away from the first dispenser. After the first resist is dispensed onto the first template, the tool can wait a period of time until the first resist diffuses into the first imprinting features of the first template. In some implementations, the first imprinting features include grating features, the grating features configured to cause the first resist to uniformly fill into the grating features. Other imprinting features can also be used and configured to uniformly diffuse the first resist.

[0173] A substrate is loaded onto the first template (1706). A first side of the substrate, e.g., a bottom side, contacts the first resist on the first template. In particular, the first side of the substrate is loaded opposite the first imprinting feature of the first template. The substrate can be a rigid substrate, e.g., a silicon wafer. A holder, e.g., top-loading EFEM 1408a in FIG. 14, can be used to hold and release the substrate onto the first template. The holder can be arranged next to the first dispenser along the moving direction of the first web.

[0174] The substrate is pressed onto the first template (1708) such that the substrate is movable with the first template. A chuck, for example, vacuum chuck 1416 of FIG. 14, can be used to chuck the substrate onto the first template. In some implementations, the first template includes one or more pre-patterned through-holes, and the substrate can be held by vacuum by the vacuum chuck through the one or more pre-patterned through-holes. The vacuum chuck is movable and can be moved with the first web and substrate after pressing.

[0175] A second resist is dispensed onto a second side of the substrate, e.g., the top side of the substrate 1710. A second dispenser is arranged next to the holder and can begin dispensing the second resist onto the substrate as the substrate is moved under the second dispenser.

[0176] A second web is stretched along a second roller. The second web includes a second template having a second imprinting feature to be imprinted on the substrate. The second roller can include two second z-rollers arranged in a horizontal direction. As illustrated in FIG. 14, the two first z-rollers define a first range of movement for the first web, and the second z-roller defines a second range of movement for the second web. The first range of movement is greater than the second range of movement and encompasses the second range of movement. The first roller and the second roller can be arranged to define a gap between the first web and the second web. The gap has a vertical distance.

[0177] The first and second web reference marks are aligned (1712). As illustrated in FIG. 15D, the first reference mark on the first web can be aligned in front of the first imprinting feature along the direction of stretching of the first web, e.g., to the left of the location where the substrate is pressed. The second reference mark on the second web can also be aligned in front of the second imprinting feature along this direction, e.g., to the left of the location where the second imprinting feature is imprinted on the second side of the substrate.

[0178] For alignment, the second web can be static and wait for the first reference mark on the first web to move close to the second reference mark. A vision system can be used to identify the location of the second reference mark and / or the first reference mark. When the first reference mark is moved to match the second reference mark, the first template is aligned with the second template, e.g., the first imprinting feature is aligned with the second imprinting feature.

[0179] After alignment, the first and second webs are stretched simultaneously at the same speed (1714). In some implementations, the second reference mark is arranged adjacent to one of the second z rollers. When the first reference mark on the first web is moved to match the second reference mark, the second web begins to be stretched along the second z roller and the second template begins to be pressed, for example, by one of the second z rollers, into the second resist on the second side of the substrate. The vertical distance of the gap between the first and second webs can be configured such that the second template is pressed into the second resist and the second resist fills into the second imprinting features of the second template.

[0180] In some implementations, the vertical distance of the gap is high so that the second resist does not contact the second template when the substrate is moved into the gap. When the first reference mark on the first web and the second reference mark on the second web are aligned, the second z-roller can be moved vertically downwards such that the second template, together with the second web, is pressed into the second resist on the second side of the substrate.

[0181] In some implementations, a squeegee roller, such as squeegee roller 608 in FIG. 6A, is moved over the second web between two second z-rollers to press the second template into the second resist so that the second resist fills into the second imprinting features. In some cases, the first resist can also be pressed into the first imprinting by the squeegee roller.

[0182] The first resist and the second resist are cured (1716). A light source, for example a UV light source, can be positioned between the two second z-rollers and can cure the first resist and the second resist when the substrate is between the first template and the second template and the first resist and the second resist are both pressed into the first imprinting feature and the second imprinting feature, respectively. Thus, the cured first resist can have a first imprinted feature corresponding to the first imprinting feature on the first side of the substrate and the hardened second resist can have a second imprinted feature corresponding to the second imprinting feature on the second side of the substrate.

[0183] The double-sided imprinted substrate is unloaded 1718. In some implementations, after curing, the second web is stretched and pulled upward along one of the second z-rollers to separate from the substrate, and then a holder, such as top-loading EFEM 1408b in FIG. 14, is used to take the substrate while the vacuum chuck under the first template releases the substrate.

[0184] 18 is a flow diagram of a third exemplary process 1800 for fabricating a double-sided imprint on a substrate. The process 1800 can be performed by the devices, systems, and / or tools described above, such as the imprinting tool 900 of FIG. 9 or the imprinting tool 1000 of FIG.

[0185] A first web is stretched along a first roller and a second web is stretched along a second roller (1802). The first web includes a first template having a first imprinting feature imprinted on one side of a substrate, and the second web includes a second template having a second imprinting feature imprinted on the other side of the substrate. The first and second templates are brought together into an imprinting zone.

[0186] The reference marks for the first and second templates are aligned (1804). A camera system or a laser system can be used to detect the reference marks on the first and second webs for alignment of the first and second templates. For example, a first imprinting feature on the first template can be aligned with a second imprinting feature on the second template by aligning a first reference mark on the first web with a second reference mark on the second web.

[0187] A first resist is dispensed onto a first side of the substrate and a second resist is dispensed onto a second side of the substrate 1806. The first resist and the second resist can be held on the sides of the substrate by surface tension.

[0188] A substrate is delivered into the imprinting zone and between the first and second templates (1808). In some cases, the substrate is rigid, for example a silicon wafer, and the substrate can be provided by gripping an edge of the substrate using a holder. In some cases, as illustrated in FIG. 10, the substrate is flexible and the substrate can be provided by pulling from a roll of blank substrates along rollers.

[0189] In some implementations, the first roller includes two first z-rollers arranged horizontally and the second roller includes two second z-rollers arranged horizontally. The first roller and / or the second roller can be moved vertically to increase or decrease the vertical distance between the first web and the second web.

[0190] The first template and the second template are pressed onto the substrate (1810) such that the first resist fills into first imprinting features of the first template on a first side of the substrate and the second resist fills into second imprinting features of the second template on a second side of the substrate.

[0191] In some implementations, a first press dome is applied to the first template, for example, from the backside of the first template. The first press dome can be a glass dome, for example, glass dome 204 of FIG. 2 or 454 of FIG. 4B. The first press dome can be an annular ring vacuum chuck, for example, vacuum chuck 104 of FIG. 1. In some implementations, the second web is supported by a planar support, for example, stage 130 of FIG. 1 or stage assembly 230 of FIG. 2. In some implementations, a second press dome is applied to the second template, for example, from the backside of the second web. The second press dome can be a glass dome, for example, glass dome 204 of FIG. 2 or 454 of FIG. 4B. The second press dome can be an annular ring vacuum chuck, for example, vacuum chuck 104 of FIG. 1.

[0192] In some implementations, after the alignment of the reference marks, the first and second press domes are brought into contact with the first and second webs. There may be a fine adjustment axis for the first or second press dome configured to make a slight correction with respect to optimal template alignment after the first or second press dome contacts the first or second web. The first and second press domes may come together evenly such that as the first and second press domes come together, the z-position of the substrate is determined by the positions of the first and second press domes. When the first and second press domes are completely flat, the first and second templates may be completely filled with the first and second resists.

[0193] In some implementations, pressing the first template and the second template onto the substrate includes moving a first squeegee roller over the first web and pressing the first template into the first resist such that the first resist fills into the first imprinting features on the first template, and / or moving a second squeegee roller over the second web and pressing the second template into the second resist such that the second resist fills into the second imprinting features on the second template. The first and second squeegee rollers can be positioned opposite each other while moving the first and second squeegees together.

[0194] The first resist and the second resist are cured, for example, by a UV light source (1812). The cured first resist can have first imprinted features corresponding to the first imprinted features on the first side of the substrate, and the hardened second resist can have second imprinted features corresponding to the second imprinted features on the second side of the substrate.

[0195] The double-sided imprinted substrate is unloaded (1814). For example, the first web can be pulled away from one of the first rollers to separate the first template from the substrate. The second web can be pulled away from one of the second rollers to separate the second template from the substrate. In some implementations, the first press dome and / or the second press dome are initially retracted from the first web and / or the second web.

[0196] In some implementations, after the substrate is separated from the first template, a first protective film is applied onto the cured first resist on the first side of the substrate. After the substrate is separated from the second template, a second protective film can be applied onto the cured second resist on the second side of the substrate. In particular, the double-sided imprinted substrate with the first and / or second protective films can be wound into a roll over a roller.

[0197] 19 is a flow diagram of a fourth exemplary process 1900 for fabricating a double-sided imprint on a substrate. The process 1900 can be performed by the devices, systems, and / or tools described above, such as the imprinting tool 800 of FIG.

[0198] A first web is stretched along a first roller and a second roller (1902). The first web includes a first template having a first imprinting feature. The first roller and the second roller can be positioned in a first direction, for example, horizontally or vertically.

[0199] A second web is stretched (1904) along a third roller and a fourth roller. The second web includes a second template having a second imprinting feature. The third roller and the fourth roller can be positioned in a second direction that is the same as the first direction, for example, horizontally or vertically. The first roller and the third roller are positioned opposite each other to define a nip. It is noted that steps 1902 and 1904 can be performed simultaneously.

[0200] The reference marks for the first and second templates are aligned (1906) such that the first template is aligned with the second template. As described above, a camera system or a laser system can be used to identify the location of the reference marks on the first and second webs for alignment. In addition, an alignment system can be used to align the reference marks for the first and second templates. For example, precision adjustment axes can be distributed between the web supports for the first and second webs such that the first and second templates can be aligned with each other.

[0201] A first resist is dispensed onto a first side of the substrate or a first template, and a second resist is dispensed onto a second side of the substrate or a second template (1908). In some cases, the first resist and the second resist can be dispensed on both sides of the substrate. In some cases, as illustrated in FIG. 8, the first resist is dispensed onto a first side of the substrate, and the second resist is dispensed onto a second template.

[0202] The first template and the second template are simultaneously stretched into the nip, and the substrate is simultaneously fed into the nip (1910). The first imprinting feature faces a first side of the substrate, the second imprinting feature faces a second side of the substrate, and the first resist can be pressed into the first imprinting feature on the first side of the substrate by a first roller, and the second resist can be pressed into the second imprinting feature on the second side of the substrate by a third roller. The substrate can be fed into the nip by using a holder that grips an edge of the substrate. The substrate can be a rigid substrate, for example, a wafer.

[0203] Once the substrate is in full contact with the first and second templates, the first web, the second web, and the substrate can stop moving. The first and second resists are cured (1912), for example, by UV light, such that the cured first resist has first imprinted features corresponding to the first imprinted features on the first side of the substrate, and the hardened second resist has second imprinted features corresponding to the second imprinted features on the second side of the substrate.

[0204] The double-sided imprinted substrate is unloaded (1914). In some implementations, step 1914 may be similar to step 1814 of FIG. 18. The first web can be pulled away from the second roller and the second web can be pulled away from the fourth roller so that the substrate is separated from the first and second templates. The substrate can be gripped by another holder. In some implementations, the first web is stretched in reverse to be pulled away from the first roller and the second web is stretched in reverse to be pulled away from the third roller. The substrate is retracted by the same holder for feeding. In such a way, the substrate can be separated from the first and second templates.

[0205] Several implementations have been described. Nevertheless, it should be understood that various modifications may be made without departing from the spirit and scope of the techniques and devices described herein. The features shown in each of the implementations may be used independently or in combination with each other. Additional features and variations may also be included in the implementations. Thus, other implementations are within the scope of the following claims.

Claims

1. A system for double-sided imprinting, comprising: a first roller for moving a first web including a first template having a first imprinting feature; a second roller for moving a second web including a second template having second imprinting features; a translation system configured to stretch the first web along the first rollers and stretch the second web along the second rollers until the first template of the first web and the second template of the second web are brought together into an imprinting zone; an alignment system configured to align reference marks for the first template and the second template; one or more dispensers configured to dispense a first resist onto a first side of a substrate and a second resist onto a second side of the substrate; a loading system configured to deliver the substrate into the imprinting zone between the first template and the second template; and a pressing system configured to press the first template and the second template onto the substrate such that the first resist fills into the first imprinting features of the first template on the first side of the substrate and the second resist fills into the second imprinting features of the second template on the second side of the substrate; a light source configured to harden the first resist and the second resist such that the hardened first resist has first imprinted features corresponding to the first imprinted features on the first side of the substrate and the hardened second resist has second imprinted features corresponding to the second imprinted features on the second side of the substrate; an unloading system configured to unload the substrate with the first imprinted feature on the first side and the imprinted feature on the second side; A system comprising:

2. The pressing system comprises: a first press dome configured to be applied onto the first template towards the substrate; or a second press dome configured to be applied onto the second template towards the substrate; The system of claim 1 , comprising at least one of:

3. The pressing system comprises: configured to bring the first press dome into contact with the first template and the second press dome into contact with the second template; The system of claim 2 , further comprising a correction system configured to perform a correction regarding alignment of the first template and the second template.

4. The system of claim 2, wherein at least one of the first press dome or the second press dome comprises a glass dome or an annular ring vacuum chuck.

5. The pressing system comprises: a first squeegee roller configured to be moved over the first web and to press the first template into the first resist such that the first resist fills into the first imprinting features on the first template; and a second squeegee roller configured to be moved over the second web and to press the second template into the second resist such that the second resist fills into the second imprinting features on the second template; and Equipped with 2. The system of claim 1, wherein the first squeegee roller and the second squeegee roller are positioned opposite one another while moving the first squeegee roller and the second squeegee roller together.

6. The substrate is rigid, The system of claim 1 , wherein the loading system comprises a holder configured to grip an edge of the substrate while feeding the substrate.

7. The substrate is flexible; The system of claim 1 , wherein the substrate is drawn from a roll of blank substrate.

8. A first roller of a first protective film configured to be applied onto the hardened first resist on the first side of the substrate; a second roller of a second protective film configured to be applied onto the cured second resist on the second side of the substrate; and The system of claim 7 further comprising:

9. The system described in claim 7, further comprising a roller configured to rotate and receive the substrate with the hardened first resist on the first side and the hardened second resist on the second side.

10. The unloading system comprises:

2. The system of claim 1 , configured to pull the first web off one of the first rollers and pull the second web off one of the second rollers to separate the first template and the second template from the substrate.

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