Patent Application
20250180985
The present disclosure relates to photomechanical shaping systems (e.g., Nanoimprint Lithography and Inkjet Adaptive Planarization). In particular, the present disclosure relates to methods of using and fabricating a nanoimprint template with a mesa sidewall coating that is used in photomechanical shaping systems.
Nano-fabrication includes the fabrication of very small structures that have features on the order of 100 nanometers or smaller. One application in which nano-fabrication has had a sizeable impact is in the fabrication of integrated circuits. The semiconductor processing industry continues to strive for larger production yields while increasing the circuits per unit area formed on a substrate. Improvements in nano-fabrication include providing one or both of greater process control and improving throughput while also allowing continued reduction of the minimum feature dimensions of the structures formed.
One nano-fabrication technique in use today is commonly referred to as nanoimprint lithography. Nanoimprint lithography is useful in a variety of applications including, for example, fabricating one or more layers of integrated devices by shaping a film on a substrate. Examples of an integrated device include but are not limited to CMOS logic, microprocessors, NAND Flash memory, NOR Flash memory, DRAM memory, MRAM, 3D cross-point memory, Re-RAM, Fe-RAM, STT-RAM, MEMS, and the like. Exemplary nanoimprint lithography systems and processes are described in detail in numerous publications, such as U.S. Pat. Nos. 8,349,241, 8,066,930, and 6,936,194, all of which are hereby incorporated by reference herein.
The nanoimprint lithography technique disclosed in each of the aforementioned patents describes the shaping of a film on a substrate by the formation of a relief pattern in a formable material (polymerizable) layer. The shape of this film may then be used to transfer a pattern corresponding to the relief pattern into, onto, or into and onto an underlying substrate.
The shaping process uses a template spaced apart from the substrate. The formable liquid is applied onto the substrate. The template is brought into contact with the formable liquid that may have been deposited as a drop pattern using the formable liquid to spread and fill the space between the template and the substrate. The formable liquid is solidified to form a film that has a shape (pattern) conforming to a shaping surface of the template. After solidification, the template is separated from the solidified layer such that the template and the substrate are spaced apart.
The substrate and the solidified layer may then be subjected to known steps and processes for device (article) fabrication, including, for example, curing, oxidation, layer formation, deposition, doping, planarization, etching, formable material removal, dicing, bonding, and packaging, and the like. For example, the pattern on the solidified layer may be subjected to an etching process that transfers the pattern into the substrate.
A first embodiment, may be a method of fabricating a template. The method of fabricating a template can comprise receiving a template with a mesa. The template has a first coating on: the mesa; a recessed surface; and mesa sidewalls connecting the recessed surface to the mesa. A first cured formable material layer has been formed on the first coating on the mesa, the mesa sidewalls, and the recessed surface using a first shaping process. Tn improvement to the method of fabricating the template can comprise: forming a second cured formable material layer on top of the first cured formable material layer on the recessed surface using a second shaping process; removing the first cured formable material layer and the first coating on the mesa, and a portion of the second cured formable material layer on the sidewalls and the recessed surface; and removing the first cured formable material layer and the second cured formable material layer from the mesa sidewalls and the recessed surface.
In an aspect of the first embodiment the second shaping process can include dispensing a plurality of droplets of formable material on the first cured formable material layer on top of the recessed surface.
In an aspect of the first embodiment the second shaping process can include contacting the first cured resist layer on the mesa with a blank template.
In an aspect of the first embodiment, the second shaping process can includes curing the uncured resist to form the second cured resist layer.
In an aspect of the first embodiment, the second shaping process can be performed M times, wherein M is an integer greater than 2.
In an aspect of the first embodiment, N can be 5.
In an aspect of the first embodiment the first shaping process can be different from the second shaping process.
In an aspect of the first embodiment, the first coating can be a 10 nm thick chrome layer deposited using an atomic layer deposition process.
In an aspect of the first embodiment, the mesa can include patterned features underneath the first coating.
In an aspect of the first embodiment removing the first cured formable material layer and the first coating on the mesa, and a portion of the second cured formable material layer on the sidewalls and the recessed surface can include exposing the first cured formable material layer and the chrome on the mesa, and the second cured formable material layer on the sidewalls and the recessed surface to a first etchant for a first etching period.
The first embodiment can further comprise, depositing a plurality of droplets of formable material onto the mesa after the first coating is removed from the mesa; contacting the plurality of droplets of formable material on the mesa with a first patterned template; exposing the plurality of droplets of formable material underneath the template to actinic radiation to form a patterned layer; exposing the patterned layer and the mesa to a second etchant forming patterns in the mesa.
The first embodiment may further comprise depositing a hard mask onto the mesas prior to depositing the droplets of formable material onto the mesa.
The first embodiment may also be a method of shaping a film on a substrate using the template fabricated using the method of the first embodiment, wherein the method of shaping the film further comprises: contacting formable material on the substrate with the template; exposing the formable material under the template to actinic radiation; and separating the template from the formable material.
The first embodiment may also be a method of manufacturing an article, from a substrate on which the film was shaped, further comprising: processing the substrate; and forming the article from the processed substrate.
A second embodiment, may be a non-transitory computer-readable medium encoded with instructions for a template fabrication system. The template fabrication system receiving a template with a mesa, wherein the template has a first coating on: the mesa; a recessed surface; and mesa sidewalls connecting the recessed surface to the mesa. A first cured formable material layer has been formed on the first coating on the mesa, the mesa sidewalls, and the recessed surface using a first shaping process. An improvement to the non-transitory computer-readable medium comprises instructions for: forming a second cured formable material layer on top of the first cured formable material layer on the recessed surface using a second shaping process; removing the first cured formable material layer and the first coating on the mesa, and a portion of the second cured formable material layer on the sidewalls and the recessed surface; and removing the first cured formable material layer and the second cured formable material layer from the mesa sidewalls and the recessed surface.
A third second embodiment, may be a controller of a template replication fabrication system configured to receive a template with a mesa. The template has a first coating on: the mesa; a recessed surface; and mesa sidewalls connecting the recessed surface to the mesa. A first cured formable material layer has been formed on the first coating on the mesa, the mesa sidewalls, and the recessed surface using a first shaping process. An improvement to the controller comprises: the controller sending instructions to the template replication tool for forming a second cured formable material layer on top of the first cured formable material layer on the recessed surface using a second shaping process; the controller sending instructions to an etching tool for removing the first cured formable material layer and the first coating on the mesa, and a portion of the second cured formable material layer on the sidewalls and the recessed surface; and the controller sending instructions to an etching tool for removing the first cured formable material layer and the second cured formable material layer from the mesa sidewalls and the recessed surface.
These and other objects, features, and advantages of the present disclosure will become apparent upon reading the following detailed description of exemplary embodiments of the present disclosure, when taken in conjunction with the appended drawings, and provided claims.
So that features and advantages of the present invention can be understood in detail, a more particular description of embodiments of the invention may be had by reference to the embodiments illustrated in the appended drawings. It is to be noted, however, that the appended drawings only illustrate typical embodiments of the invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.
Throughout the figures, the same reference numerals and characters, unless otherwise stated, are used to denote like features, elements, components, or portions of the illustrated embodiments. Moreover, while the subject disclosure will now be described in detail with reference to the figures, it is done so in connection with the illustrative exemplary embodiments. It is intended that changes and modifications can be made to the described exemplary embodiments without departing from the true scope and spirit of the subject disclosure as defined by the appended claims.
The nanoimprint lithography technique can use a template with a mesa to shape a formable material with the mesa in a plurality of fields across a substrate. This is done by contacting formable material with the mesa and curing the formable material under the mesa with actinic radiation. The formable material may spread out beyond the mesa during this process forming extrusions. The applicant has found that it is desirable to prevent the extrusions from curing. The applicant has found that an effective way of preventing the extrusions from curing is to coat mesa sidewalls of the template with a material that absorbs the actinic radiation as described in US Patent Publication No. 2023-0095286-A1. The applicant has found that this method is not 100% and small pinholes can form in the coating allowing extrusions to form. What is needed is a method of applying the coating such that pinholes do not form.
The substrate 102 and the substrate chuck 104 may be further supported by a substrate positioning stage 106. The substrate positioning stage 106 may provide translational motion, rotational motion, or both along one or more of the positional axes x, y, and z, and rotational axes θ, ψ, and φ. The substrate positioning stage 106, the substrate 102, and the substrate chuck 104 may also be positioned on a base (not shown). The substrate positioning stage may be a part of a positioning system. In an alternative embodiment, the substrate chuck 104 may be attached to the base.
Spaced-apart from the substrate 102 is a template 108 (also referred to as a superstrate). The template 108 may include a body having a mesa 110 extending towards the substrate 102 on a front side of the template 108. The mesa 110 may have a shaping surface 112 thereon also on the front side of the template 108. The shaping surface 112, also known as a patterning surface, is the surface of the template that shapes the formable material 124. In an embodiment, the shaping surface 112 is planar and is used to planarize the formable material. Alternatively, the template 108 may be formed without the mesa 110, in which case the surface of the template facing the substrate 102 is equivalent to the mesa 110 and the shaping surface 112 is that surface of the template 108 facing the substrate 102, the mesa sidewalls are the sidewalls of the template 108.
The template 108 may be formed from such materials including, but not limited to, one or more of: fused-silica; quartz; silicon; organic polymers; siloxane polymers; borosilicate glass; fluorocarbon polymers; metal; hardened sapphire; and the like. The shaping surface 112 may have features defined by a plurality of spaced-apart template recesses 114 and template protrusions 116. The shaping surface 112 defines a pattern that forms the basis of a pattern to be formed on the substrate 102. In an alternative embodiment, the shaping surface 112 is featureless in which case a planar surface is formed on the substrate. In an alternative embodiment, the shaping surface 112 is featureless and the same size as the substrate and a planar surface is formed across the entire substrate.
Template 108 may be coupled to a template chuck 118. The template chuck 118 may be, but is not limited to one or more of: vacuum chuck; pin-type chuck; groove-type chuck; electrostatic chuck; electromagnetic chuck; and other similar chuck types. The template chuck 118 may be configured to apply one or more of: stress; pressure; and strain to template 108 that varies across the template 108. The template chuck 118 may include a template magnification control system 121. The template magnification control system 121 may include piezoelectric actuators (or other actuators) which can squeeze, stretch, or both squeeze and stretch different portions of the template 108. The template chuck 118 may include a system such as a zone based vacuum chuck, an actuator array, a pressure bladder, etc. which can apply a pressure differential to a back surface of the template causing the template to bend and deform.
The template chuck 118 may be coupled to a shaping head 120 which is a part of the positioning system. The shaping head 120 may be moveably coupled to a bridge. The shaping head 120 may include one or more actuators such as voice coil motors, piezoelectric motors, linear motor, nut and screw motor, etc., which are configured to move the template chuck 118 relative to the substrate in at least the z-axis direction, and potentially other directions (e.g., positional axes x, and y, and rotational axes θ, ψ, and φ).
The shaping system 100 may further comprise a fluid dispenser 122. The fluid dispenser 122 may also be moveably coupled to the bridge. In an embodiment, the fluid dispenser 122 and the shaping head 120 share one or more or all of the positioning components. In an alternative embodiment, the fluid dispenser 122 and the shaping head 120 move independently from each other. The fluid dispenser 122 may be used to deposit liquid formable material 124 (e.g., polymerizable material) onto the substrate 102 in a drop pattern. Additional formable material 124 may also be added to the substrate 102 using one or more techniques, such as, drop dispense, spin-coating, dip coating, chemical vapor deposition (CVD), physical vapor deposition (PVD), thin film deposition, thick film deposition, and the like prior to the formable material 124 being deposited onto the substrate 102. The formable material 124 may be dispensed upon the substrate 102 before, after, or both before and after a desired volume is defined between the shaping surface 112 and the substrate 102 depending on design considerations. The formable material 124 may comprise a mixture including a monomer as described in U.S. Pat. Nos. 7,157,036 and 8,076,386, both of which are herein incorporated by reference.
Different fluid dispensers 122 may use different technologies to dispense formable material 124. When the formable material 124 is jettable, ink jet type dispensers may be used to dispense the formable material. For example, thermal ink jetting, microelectromechanical systems (MEMS) based ink jetting, valve jet, and piezoelectric ink jetting are common techniques for dispensing jettable liquids.
The shaping system 100 may further comprise a curing system that induces a phase change in the liquid formable material into a solid material whose top surface is determined by the shape of the shaping surface 112. The curing system may include at least a radiation source 126 that directs actinic energy along an exposure path 128. The shaping head and the substrate positioning stage 106 may be configured to position the template 108 and the substrate 102 in superimposition with the exposure path 128. The radiation source 126 sends the actinic energy along the exposure path 128 after the template 108 has contacted the formable material 124.
The shaping system 100 may further comprise a field camera 136 that is positioned to view the spread of formable material 124 after the template 108 has contacted the formable material 124.
The shaping system 100 may further comprise a droplet inspection system 138 that is separate from the field camera 136. The droplet inspection system 138 may include one or more of a CCD, a camera, a line camera, and a photodetector. The droplet inspection system 138 may include one or more optical components such as: lenses, mirrors, optical diaphragms, apertures, filters, prisms, polarizers, windows, adaptive optics, and light sources. The droplet inspection system 138 may be positioned to inspect droplets prior to the shaping surface 112 contacting the formable material 124 on the substrate 102. In an alternative embodiment, the field camera 136 may be configured as a droplet inspection system 138 and used prior to the shaping surface 112 contacting the formable material 124.
The shaping system 100 may further include a thermal radiation source 134 which may be configured to provide a spatial distribution of thermal radiation to one or both of the template 108 and the substrate 102. The thermal radiation source 134 may include one or more sources of thermal electromagnetic radiation that will heat up one or both of the substrate 102 and the template 108 and does not cause the formable material 124 to solidify. The thermal radiation source 134 may include a SLM such as a digital micromirror device (DMD), Liquid Crystal on Silicon (LCoS), Liquid Crystal Device (LCD), etc., to modulate the spatio-temporal distribution of thermal radiation. The shaping system 100 may further comprise one or more optical components which are used to combine the actinic radiation, the thermal radiation, and the radiation gathered by the field camera 136 onto a single optical path that intersects with the imprint field when the template 108 comes into contact with the formable material 124 on the substrate 102. The thermal radiation source 134 may send the thermal radiation along a thermal radiation path (which in
Prior to the formable material 124 being dispensed onto the substrate, a substrate coating 132 may be applied to the substrate 102. In an embodiment, the substrate coating 132 may be an adhesion layer. In an embodiment, the substrate coating 132 may be applied to the substrate 102 prior to the substrate being loaded onto the substrate chuck 104. In an alternative embodiment, the substrate coating 132 may be applied to substrate 102 while the substrate 102 is on the substrate chuck 104. In an embodiment, the substrate coating 132 may be applied by spin coating, dip coating, drop dispense, slot dispense, etc. In an embodiment, the substrate 102 may be a semiconductor wafer. In another embodiment, the substrate 102 may be a blank template (replica blank) that may be used to create a daughter template after being imprinted.
The shaping system 100 may include an imprint field atmosphere control system that includes one or both of a gas system and a vacuum system, an example of which is described in U.S. Patent Publication Nos. 2010/0096764 and 2019/0101823 which are hereby incorporated by reference. The atmosphere control system may include one or more of pumps, valves, solenoids, gas sources, gas tubing, etc. which are configured to cause one or more different gases to flow at different times and different regions. The atmosphere control system may be connected to a first gas transport system that transports gas to and from the edge of the substrate 102 and controls the imprint field atmosphere by controlling the flow of gas at the edge of the substrate 102. The atmosphere control system may be connected to a second gas transport system that transports gas to and from the edge of the template 108 and controls the imprint field atmosphere by controlling the flow of gas at the edge of the template 108. The atmosphere control system may be connected to a third gas transport system that transports gas to and from the top of the template 108 and controls the imprint field atmosphere by controlling the flow of gas through the template 108. One or more of the first, second, and third gas transport systems may be used in combination or separately to control the flow of gas in and around the imprint field.
The shaping system 100 can be regulated, controlled, directed by one or more processors 140 (controller) in communication with one or more components and subsystems such as the substrate chuck 104, the substrate positioning stage 106, the template chuck 118, the shaping head 120, the fluid dispenser 122, the radiation source 126, the thermal radiation source 134, the field camera 136, imprint field atmosphere control system, and the droplet inspection system 138. The processor 140 may operate based on instructions in a computer readable program stored in a non-transitory computer readable memory 142. The processor 140 may be or include one or more of a CPU, MPU, GPU, ASIC, FPGA, DSP, and a general-purpose computer. The processor 140 may be a purpose-built controller or may be a general-purpose computing device that is adapted to be a controller. Examples of a non-transitory computer readable memory include but are not limited to RAM, ROM, CD, DVD, Blu-Ray, hard drive, networked attached storage (NAS), an intranet connected non-transitory computer readable storage device, and an internet connected non-transitory computer readable storage device. The controller 140 may include a plurality of processors that are both included in the shaping system 100a and in communication with the shaping system 100a. The processor 140 may be in communication with a networked computer 140a on which analysis is performed and control files such as a drop pattern are generated. In an embodiment, there are one or more graphical user interface (GUI) 141 on one or both of the networked computer 140a and a display in communication with the processor 140 which are presented to an operator or user.
Either the shaping head 120, the substrate positioning stage 106, or both varies a distance between the mesa 110 and the substrate 102 to define a desired space (a bounded physical extent in three dimensions) that is filled with the formable material 124. For example, the shaping head 120 may apply a force to the template 108 such that mesa 110 is in contact with the formable material 124. After the desired volume is filled with the formable material 124, the radiation source 126 produces actinic radiation (e.g., UV, 248 nm, 280 nm, 350 nm, 365 nm, 395 nm, 400 nm, 405 nm, 435 nm, etc.) causing the formable material 124 to undergo a chemical reaction such as curing, solidifying, cross-linking. The formable material 134 will also conform to a shape of the substrate surface 130 and the shaping surface 112, defining a patterned layer on the substrate 102. The formable material 124 is cured while the template 108 is in contact with formable material 124, forming the patterned layer on the substrate 102. Thus, the shaping system 100 uses a shaping process to form the patterned layer which has recesses and protrusions which are an inverse of the pattern in the shaping surface 112. In an alternative embodiment, the shaping system 100 uses a shaping process to form a planar layer with a featureless shaping surface 112.
The shaping process may be done repeatedly in a plurality of imprint fields (also known as just fields or shots) that are spread across the substrate surface 130. Each of the imprint fields may be the same size as the mesa 110 or just the pattern area of the mesa 110. The pattern area of the mesa 110 is a region of the shaping surface 112 which is used to imprint patterns on a substrate 102 which are features of the device or are then used in subsequent processes to form features of the device. The pattern area of the mesa 110 may or may not include mass velocity variation features (fluid control features) which are used to prevent extrusions from forming on imprint field edges. In an alternative embodiment, the substrate 102 has only one imprint field which is the same size as the substrate 102 or the area of the substrate 102 which is to be patterned with the mesa 110. In an alternative embodiment, the imprint fields overlap. Some of the imprint fields may be partial imprint fields which intersect with a boundary of the substrate 102.
The patterned layer may be formed such that it has a residual layer having a residual layer thickness (RLT) that is a minimum thickness of formable material 124 between the substrate surface 130 and the shaping surface 112 in each imprint field. The patterned layer may also include one or more features such as protrusions which extend above the residual layer having a thickness. These protrusions match the recesses 114 in the mesa 110.
In an alternative embodiment, the shaping process 300 is used to planarize the substrate 102. In which case, the shaping surface 112 is featureless and may also be the same size or larger than the substrate 102.
The beginning of the shaping process 300 may include a template mounting step causing a template conveyance mechanism to mount a template 108 onto the template chuck 118. The shaping process 300 may also include a substrate mounting step, the processor 140 may cause a substrate conveyance mechanism to mount the substrate 102 onto the substrate chuck 104. The substrate may have one or more coatings and structures. The order in which the template 108 and the substrate 102 are mounted onto the shaping system 100 is not particularly limited, and the template 108 and the substrate 102 may be mounted sequentially or simultaneously.
In a positioning step, the processor 140 may cause one or both of the substrate positioning stage 106 and a dispenser positioning stage to move an imprinting field i (index i may be initially set to 1) of the substrate 102 to a fluid dispense position below the fluid dispenser 122. The substrate 102, may be divided into N imprinting fields, wherein each imprinting field is identified by a shaping field index i. In which N is the number of shaping fields and is a real positive integer such as 1, 10, 62, 75, 84, 100, etc. {N∈+}. In a dispensing step S302, the processor 140 may cause the fluid dispenser 122 to dispense formable material based on a drop pattern onto an imprinting field. In an embodiment, the fluid dispenser 122 dispenses the formable material 124 as a plurality of droplets. The fluid dispenser 122 may include one nozzle or multiple nozzles. The fluid dispenser 122 may eject formable material 124 from the one or more nozzles simultaneously. The imprint field may be moved relative to the fluid dispenser 122 while the fluid dispenser is ejecting formable material 124. Thus, the time at which some of the droplets land on the substrate may vary across the imprint field i. The dispensing step S302 may be performed during a dispensing period Td for each imprint field i.
In an embodiment, during the dispensing step S302, the formable material 124 is dispensed onto the substrate 102 in accordance with a drop pattern. The drop pattern may include information such as one or more of: position to deposit drops of formable material, the volume of the drops of formable material, type of formable material, shape parameters of the drops of formable material, etc. In an embodiment, the drop pattern may include only the volumes of the drops to be dispensed and the location of where to deposit the droplets.
After, the droplets are dispensed, then a contacting step S304 may be initiated, the processor 140 may cause one or both of the substrate positioning stage 106 and a template positioning stage to bring the shaping surface 112 of the template 108 into contact with the formable material 124 in a particular imprint field. The contacting step S304 may be performed during a contacting period Tcontact which starts after the dispensing period Td and begins with the initial contact of the shaping surface 112 with the formable material 124. In an embodiment, at the beginning of the contact period Tcontact the template chuck 118 is configured to bow out the template 108 so that only a portion of the shaping surface 112 is in contact with a portion of the formable material. In an embodiment, the contact period Tcontact ends when the template 108 is no longer bowed out by the template chuck 118. The degree to which the shaping surface 112 is bowed out relative to the substrate surface 130 may be estimated with the spread camera 136. The spread camera 136 may be configured to record interference fringes due to reflectance from at least the shaping surface 112 and the substrate surface 130. The greater the distance between neighboring interference fringes, the larger the degree to which the shaping surface 112 is bowed out.
During a filling step S306, the formable material 124 spreads out towards the edge of the imprint field and the mesa sidewalls 246. The edge of the imprint field may be defined by the mesa sidewalls 246. How the formable material 124 spreads and fills the mesa may be observed via the field camera 136 and may be used to track a progress of a fluid front of formable material. In an embodiment, the filling step S306 occurs during a filling period Tf. The filling period Tf begins when the contacting step S304 ends. The filling period Tf ends with the start of a curing period Tc. In an embodiment, during the filling period Tf the back pressure and the force applied to the template are held substantially constant. Substantially constant in the present context means that the back pressure variation and the force variation is within the control tolerances of the shaping system 100 which may be less 0.1% of the set point values.
In a curing step S308, the processor 140 may send instructions to the radiation source 126 to send a curing illumination pattern of actinic radiation through the template 108, the mesa 110, and the shaping surface 112 during a curing period Tc. The curing illumination pattern provides enough energy to cure (polymerize) the formable material 124 under the shaping surface 112. The curing period Tc is a period in which the formable material under the template receives actinic radiation with an intensity that is high enough to solidify (cure) the formable material. In an alternative embodiment, the formable material 124 is exposed to a gelling illumination pattern of actinic radiation before the curing period Tc which does not cure the formable material but does increase the viscosity of the formable material.
In a separation step S310, the processor 140 uses one or more of: the substrate chuck 104, the substrate positioning stage 106, template chuck 118, and the shaping head 120 to separate the shaping surface 112 of the template 108 from the cured formable material on the substrate 102 during a separation period Ts. If there are additional imprint fields to be imprinted, then the process moves back to step S302. In an alternative embodiment, during step S302 two or more imprint fields receive formable material 124 and the process moves back to steps S302 or S304.
In an embodiment, after the shaping process 300 is finished additional semiconductor manufacturing processing is performed on the substrate 102 in a processing step S312 so as to create an article of manufacture (e.g., semiconductor device). In an embodiment, each imprint field includes a plurality of devices.
The further semiconductor manufacturing processing in processing step S312 may include etching processes to transfer a relief image into the substrate that corresponds to the pattern in the patterned layer or an inverse of that pattern. The further processing in processing step S312 may also include known steps and processes for article fabrication, including, for example, inspection, curing, oxidation, layer formation, deposition, doping, planarization, etching, formable material removal, dicing, bonding, packaging, mounting, circuit board assembly, and the like. The substrate 102 may be processed to produce a plurality of articles (devices).
The process of template replication uses shaping process 300 but it is done only one time. Steps S312 of the template replication process may include etching, cleaning, inspecting, and forming coating on the mesa sidewalls. In an alternative embodiment, a coating is formed on the mesa sidewalls of the blank template prior to performing the shaping process 300.
However, the filling process can cause some formable material 124 to extrude beyond the mesa sidewalls 246 of the mesa 110 forming a liquid extrusion 524c as illustrated in
The applicant has found that performance of the template 108 is improved when a mesa sidewall coating 548 is applied to the mesa sidewalls 246. The mesa sidewall coating 548 may include one or more of: a metal; a hydrophobic coating; a gas absorption coating; a conductive coating; a hardening coating, an actinic radiation absorbing coating; and an actinic radiation reflecting coating. As illustrated in
As seen in
The quality of the mesa sidewall coating 548 is very important to the performance of the shaping system 100. The applicant has developed a method of testing the quality of the mesa sidewall coating 548. The testing method includes depositing droplets of formable material 124 on the substrate in the imprint field and on the imprint field edge right below the mesa as illustrated in
The imprinted film will then be inspected for extrusions.
The applicant has developed a new mesa sidewall coating method 600 that improves upon previous methods of coating the mesa sidewalls described by a flowchart in
The mesa sidewall coating method 600 may include a first coating step S602. The first coating step S604 may include depositing a first coating 752 on: the mesa 110; the mesa sidewalls 246; and the recessed surface 244 as illustrated in
The mesa sidewall coating method 600 may include a first shaping process S606. The details of the first shaping process S606 are described in US Patent Publication No. 2023-0095286-A1 which is hereby incorporated by reference. An intermediate product of the first shaping process is a first cured formable material layer 754a as illustrated in
The mesa sidewall coating method 600 may include a second shaping process S608. The second shaping process S608 is a process of forming second cured formable material layer 754b on the recessed surface 244 so that the total thickness of cured formable material on the recessed surface 244 has a fourth thickness t4 as illustrated in
The mesa sidewall coating method 600 may include a criteria testing step S610. The criteria testing step S610 is a test that is correlated with the tested or predicted extrusion performance of the template. Extrusion performance means the statistical probability that an extrusion will be formed during the imprinting process over the life of the template. This extrusion performance may be based on experimental testing of templates to obtain images such as those illustrated in
The mesa sidewall coating method 600 may include an etching step S612. The etching step S612 includes a plurality of etching substeps. A first etching substep may include removing cured formable material from the mesa as illustrated in
The etching step S612 includes a second etching substep. The second etching substep may be an isotropic etching process or an anisotropic etching process. The second etching substep may include exposing the first coating 752 to one or more of a liquid, a gas, and a plasma for a period of time such that the patterned features under the chrome on the mesa and the alignment marks are exposed. The second etching substep has an etching differential between the first coating 752, the material of the mesa, and the total cured formable material 754d on the recessed surface 244 and the mesa sidewalls 246. The second etching substep may also have an etching differential between the alignment marks 750 and the first coating 752. The alignment marks 750 may have a protective coating or may be made of a different material from the first coating 752. After the second etching substep the first coating 752 is removed from the mesa and the total cured formable material 754d has a sixth thickness t6 that is less than a fifth thickness t5 as illustrated in
The etching step S612 includes a third etching substep which may be a descumming step. The third etching substep includes removing substantially all of the remaining formable material leaving a template that has a first coating on the mesa sidewall without pinholes or other openings close to the mesa sidewalls. The patterned template 708 includes features that have a maximum depth d. The maximum depth may be between 1-250 nm. In a first embodiment, the mesa may be surrounded by a step that has with a maximum depth d surrounding the mesa. In a second embodiment, the first coating does not extend to the top of the mesa, but extends close to the maximum depth d from the top of the mesa.
The first shaping process S606 is summarized in
The first shaping process S606 can include a first contacting step S618. The first contacting step S618 can include contacting liquid formable material 124 on the mesa with a blank template. The first contacting step S618 is performed such that the formable material spreads and fills the features on the mesa and forms extrusions on the mesa sidewall.
The first shaping process S606 can include a first curing step S620. The first curing step S620 can include exposing the formable material 124 to curing energy. The curing energy may be actinic radiation, thermal energy, or chemical energy, or some other method of curing, solidifying, cross-linking, the formable material to form the first cured formable material layer 754a. In an embodiment, the first cured formable material layer 754a includes: material on the mesa 110, extrusions on the mesa sidewalls 266, and material on the recessed surface 244. In an embodiment, the first cured formable material layer 754a includes: material on the mesa 110, extrusions on the mesa sidewalls 266, and material on some of the recessed surface 244. In an embodiment, the first cured formable material layer 754a includes: material on the mesa 110 and extrusions on the mesa sidewalls 266. In an embodiment, the first cured formable material layer 754a includes material on the mesa 110.
The second shaping process S608 is summarized in
The second shaping process S608 can include a second contacting step S624. The second contacting step S618 can include contacting first cured formable material layer 754a on the mesa with a blank template as illustrated in
The second shaping process S608 can include a second curing step S620. The second curing step S620 can include exposing the formable material 124 to curing energy. The curing energy may be actinic radiation, thermal energy, or chemical energy, or some other method of curing, solidifying, cross-linking, the formable material to form the second cured formable material layer 754b as illustrated in
Further modifications and alternative embodiments of various aspects will be apparent to those skilled in the art in view of this description. Accordingly, this description is to be construed as illustrative only. It is to be understood that the forms shown and described herein are to be taken as examples of embodiments. Elements and materials may be substituted for those illustrated and described herein, parts and processes may be reversed, and certain features may be utilized independently, all as would be apparent to one skilled in the art after having the benefit of this description.
