Patent Application
20050275251
The field of invention relates generally to remote center compliant devices. More particularly, the present invention is directed to a compliant device suited for use in imprint lithography to hold a template.
Compliant devices are devices that have elastic properties to compliantly float one body relative to another, while providing a desired number of degrees of freedom of movement therebetween. These properties permit, inter alia, the floating body to compensate out-of-tolerance spatial orientations with respect to a work surface. Active compliant devices use actuators to achieve a desired spatial orientation between bodies. “Passive” compliant devices are unpowered, i.e., with out active control. Being able to be kinematically constrained in any translational or rotational direction, a “passive” compliant device achieves proper spatial orientation between the floating body and a work piece through interconnecting linkages and passive elastic elements, e.g., springs. Actuation of the compliance function occurs upon contact of the floating body with the work surface. To that end, forces transferred between the floating body and a support body coupled thereto via linkages may be achieved serially or in parallel.
An exemplary compliant device is shown in U.S. Pat. No. 6,696,220 to Bailey et al. that discloses a remote passive compliant device for use in imprint lithography. The remote passive compliant device facilitates a transfer of forces between the floating body and a support body coupled thereto serially, through a plurality of linkages. The linkages are coupled between the floating body and the support by via flexure joints. With this configuration, proper spatial orientation between an imprint lithography template and imprinting material of a work surface may be achieved.
Thus, a need exists for providing improved compliant devices for use in imprint lithography processes.
The present invention is directed to a compliant device comprising a support body, a floating body, and a plurality of flexure arms. Each of the plurality of transfer arms is connected between the support body and the floating body to transfer a load therebetween in parallel. To that end, the flexure arms having first and second sets of flexure joints. The first set of flexure joints facilitate rotational movement of the flexure arm about a first axis extending along a first direction. The second set of flexure joints arranged to facilitate rotational movement of the flexure arm about a second axis, extending along a second direction that is transverse to the first direction. The flexure joints are revolute joints. Thus, the movement of the flexure arms is constrained to rotational movement about two transversely orientated axes. In one embodiment the compliant device is a passive compliant device. In an alternate embodiment, the compliant device is an active compliant device. These and other embodiments are discussed more fully below.
Referring to
Referring to
Orientation stage 10 is configured to control movement of template 22 and place the same in a desired spatial relationship with respect to a reference surface (not shown). To that end, plurality of actuators 40, 42, and 44 are connected between outer frame 14 and inner frame 12 so as to be spaced about orientation stage 10. Each of actuators 40, 42, and 44 has a first end 46 and a second end 48. First end 46 of actuator 40 faces outer frame 14, and second end 48 faces inner frame 12. Actuators 40, 42, and 44 tilt inner frame 12 with respect to outer frame 14 by facilitating translational motion of inner frame 12 along three axes Z1, Z2, and Z3. Orientation stage 10 may provide a range of motion of approximately ±1.2 mm about axes Z1, Z2, and Z3. In this fashion, actuators 40, 42, and 44 cause inner frame 12 to impart angular motion to both compliant device 18 and, therefore, template 22 and template chuck 20, angular motion about one or more of a plurality of axes T1, T2 and T3. Specifically, by decreasing a distance between inner frame 12 and outer frame 14 along axes Z2 and Z3 and increasing a distance therebetween along axis Z1, angular motion about tilt axis T2 occurs in a first direction. Increasing the distance between inner frame 12 and outer frame 14 along axes Z2 and Z3 and decreasing the distance therebetween along axis Z1, angular motion about tilt axis T2 occurs in a second direction opposite to the first direction. In a similar manner angular movement about axis T1 may occur by varying the distance between inner frame 12 and outer frame 14 by movement of inner frame 12 along axes Z1 and Z2 in the same direction and magnitude while moving of the inner frame 12 along axis Z3 in a direction opposite and twice to the movement along axes Z1 and Z2. Similarly, angular movement about axis T3 may occur by varying the distance between inner frame 12 and outer frame 14 by movement of inner frame 12 along axes Z1 and Z3 in the same direction and magnitude while moving of inner frame 12 along axis Z2 in direction opposite and twice to the movement along axes Z1 and Z3. Actuators 40, 42, and 44 may have a maximum operational force of ±200 N. Orientation stage 10 may provide a range of motion of approximately +0.150 about axes T1, T2, and T3.
Actuators 40, 42, and 44 are selected to minimize mechanical parts and, therefore, minimize uneven mechanical compliance, as well as friction, which may cause particulates. Examples of actuators 40, 42, and 44 include voice coil actuators, piezo actuators, and linear actuators. An exemplary embodiment for actuators 40, 42, and 44 is available from BEI Technologies of Sylmar, Calif. under the trade name LA24-20-000A. Additionally, actuators 40, 42, and 44 are coupled between inner frame 12 and outer frame 14 so as to be symmetrical disposed thereabout and lie outside of central throughway 24 and central opening 26. With this configuration an unobstructed throughway between outer frame 14 to compliant device 18 is configured. Additionally, the symmetrical arrangement minimizes dynamic vibration and uneven thermal drift, thereby providing fine-motion correction of inner frame 12.
The combination of the inner frame 12, outer frame 14, flexure ring 16 and actuators 40, 42, and 44 provides angular motion of compliant device 18 and, therefore, template chuck 20 and template 22 about tilt axes T1, T2 and T3. It is desired, however, that translational motion be imparted to template 22 along axes that lie in a plane extending transversely, if not orthogonally, to axes Z1, Z2, and Z3. This is achieved by providing compliant device 18 with a functionality to impart angular motion upon template 22 about one or more of a plurality of compliance axes, shown as C1 and C2, which are spaced-part from tilt axes T1, T2 and T3 and exist on the surface of the template when the template, the template chuck, and the compliant device are assembled.
Referring to
Each of flexure arms 54, 56, 58, and 60 includes first and second sets of flexure joints 62, 64, 66, and 68. The first and second sets of flexure joints 62, 64, 66, and 68 are discussed with respect to flexure arm 56 for ease of discussion, but this discussion applies equally to the sets of flexure joints associated with flexure arms 56, 58, and 60. Although it is not necessary, compliant device 18 is formed from a solid body, for example, stainless steel. As a result, support body 50, floating body 52 and flexures arms 54, 56, 58, and 60 are integrally formed and are rotationally coupled together vis-à-vis first and second sets of flexure joints 62, 64, 66, and 68. Support body 50 includes a centrally disposed throughway 70. Floating body includes a centrally disposed aperture 72 that is in superimposition with throughway 70. Each flexure arm 54, 56, 58, and 60 includes opposed ends, 74 and 76. End 74 of each flexure arms 54, 56, 58, and 60 is connected to support body 50 through flexure joints 66 and 68. End 74 lies outside of throughway 70. End 76 of each flexure arm 54, 56, 58, and 60 is connected to floating body 52 through flexure joints 62 and 64. End 76 lies outside of aperture 72.
Referring to
Referring to
As a result, each flexure arm 54, 56, 58, and 60 is located at a region of said device 18 where groups of the axes of rotation overlap. For example, end 74 of flexure arm 54 is located where axes 110 and 114 overlap and end 76 is positioned where axes 108 and 112 overlap. End 74 of flexure arm 56 is located where axes 106 and 114 overlap, and end 76 is positioned where axes 110 and 112 overlap. End 74 of flexure arm 58 is located where axes 106 and 118 overlap, and end 76 is located where axes 104 and 116 overlap. Similarly, end 74 of flexure arm 60 is located where axes 110 and 118 overlap, and end 76 is located where 108 and 116 overlap.
As a result of this configuration, each flexure arm 54, 56, 58, and 60 is coupled to provide relative rotational movement with respect to support body 50 and floating body 52 about two groups of overlapping axes with a first group extending transversely to the remaining group. This provides each of flexure arms 54, 56, 58, and 60 with movement about two groups of orthogonal axes while minimizing the footprint of the same. Device 18 may provide a tilting motion range of approximately ±0.040, an active tilting motion range of approximately ±0.020, and an active theta motion range of approximately ±0.00050 above the above mentioned axes. Furthermore, having the reduced footprint of each flexure arm 54, 56, 58, and 60 allows leaving a void 120 between throughway 70 and aperture 72 unobstructed by flexure arms 54, 56, 58, and 60. This makes device 18 suited for use with an imprint lithography system, discussed more fully below.
Referring to
Referring to
Two sets of transversely extending axes may be in substantially close proximity such that RCC 122 may be considered to lie upon an intersection thereat by appropriately establishing distances d1-d8. A first set of includes four axes is shown as 124, 126, 128, and 130. Joints 62 and 66 of flexure arm 54 lie along axis 124, and joints 62 and 66 of flexure arm 56 lie along axis 126. Joints 62 and 66 of flexure arm 58 lie along axis 128, and joints 62 and 66 of flexure arm 60 lie along axis 130. A second set of four axes is shown as 132, 134, 136, and 138. Joints 64 and 68 of flexure arm 56 lie along axis 132, and joints 64 and 68 of flexure arm 58 lie along axis 134. Joints 64 and 68 of flexure arm 60 lie along axis 136, and joints 64 and 68 of flexure arm 54 lie along axis 138. With this configuration movement of floating body 52, with respect to RCC 122, about any one of the set of axes 124, 126, 128, 130, 132, 134, 136, and 138 is decoupled from movement about the remaining axes 124, 126, 128, 130, 132, 134, 136, and 138. This provides a gimbal-like movement of floating body 52 with respect to RCC 122, with the structural stiffness to resist, if not prevent, translational movement of floating body with respect to axis 124, 126, 128, 130, 132, 134, 136, and 138.
Referring to
To provide rotational movement of floating body 52 with respect to support body 50 actuators 150, 152, 154, and 156 may be activated. For example, actuator 150 may be activated to move lever arm 140 along the F1 direction and actuator 154 would be operated to move lever arm 146 in a direction opposite to the direction lever arm 140 moves. Similarly, at least one of actuators 152 and 156 are activated to move lever arms 142 and 148 respectively. Assuming both actuators 152 and 156 are activated, then each of lever arms 140, 142, 146, and 148 are moved toward one of flexure arms 54, 56, 58, and 60 that differs from the flexure arm 54, 56, 58, and 60 toward which the remaining lever arms 140, 142, 146, and 148 move. An example may include moving lever arm 140 toward flexure arm 54, lever arm 142 toward flexure arm 56, lever arm 146 toward flexure arm 58 and lever arm 142 toward flexure arm 60. This would impart rotational movement about the F3 direction. It should be understood, however, each of lever arms 140, 142, 146, and 148 may be moved in the opposite direction. Were it desired to prevent translational displacement between support body 50 and floating body 52 along the F3 direction while imparting rotational movement thereabout, then each of lever arms 140, 142, 146, and 148 would be moved the same magnitude. However, were it desired to impart rotational movement of floating body 52 about the F1 and F2 directions, this may be achieved in various manners.
Since rotational movement of floating body 52 is guided by the first and second RCCS, floating body 52 can be actively adjusted for two independent angular configuration with respect to support body by translation along the F3 direction. For example, moving each of lever arms 140, 142, 146, and 148 with actuators 150, 152, 154, and 156, respectively, differing amounts would impart translation of floating body 52 along the F3 direction while imparting angular displacement about the F3 direction. Additionally, moving only three lever arms 140, 142, 146, and 148 would also impart translation motion about the F3 direction while imparting angular displacement about the F3 direction. Were it desired to provide impart translational motion between support body 50 and floating body 52 without impart rotational movement therebetween, two of actuators 150, 152, 154, and 156 would be activated to move two of lever arms 140, 142, 146, and 148. In one example, two opposing lever arms, such as for example, 140 and 146, or 142 and 148 would be moved in the same direction the same magnitude. Moving lever arms 140 and 146 in one direction, e.g., toward flexure arms 60 and 58, respectively, would cause the entire side of floating body 52 extending between flexure arms 58 and 60 to increase in distance from the side of support body 50 in superimposition therewith, effectively creating rotation movement of floating body 16 about the F2 direction. Decrease would the distance between the side of floating body 52 extending between flexure arms 56 and 54 and the side of support body 50 in superimposition therewith. Conversely, moving lever arms 140 and 146 in an opposite direction, e.g., toward flexure arms 54 and 56, would cause the entire side of floating body 52 extending between flexure arms 58 and 60 to decrease in distance from the side of support body 50. The distance between the side of floating body 52 extending between flexure arms 58 and 60 and the side of support body 50 in superimposition therewith would increase. Similarly, rotational movement of floating body 52 about the F1 direction may be achieved by movement of lever arms 142 and 148 with actuators 152 and 156, respectively, as discussed above with respect to movement of lever arms 140 and 146. It should be understood that any linear combination of movement of the aforementioned lever arms may be effectuated to achieve desired motion.
From the foregoing it is seen that rotational motions of floating body 52 about the F1, F2 and F3 directions are orthogonal to each other. By adjusting the magnitude of each actuation force or position at actuators 150, 152, 154 and 156, any combination or rotational motions about the F1, F2 and F3 directions are constrained by the structural stiffness of flexure arms 54, 56, 58, and 60, floating body 52 and support body 50.
Referring to
Template 22 and substrate 158 are shown spaced-apart a distance defining a gap 160 therebetween. The volume associated with gap 160 is dependent upon many factors, including the topography of the surface of template 22 facing substrate and the surface of substrate 158 facing template 22, as well as the angular relationship between a neutral axis A of substrate with respect to the neutral axis B of substrate 158. In addition, were the topography of both of the aforementioned surfaces patterned, the volume associated with gap 160 would also be dependent upon the angular relation between template 22 and substrate 158 about axis Z. Considering that desirable patterning with imprint lithography techniques is, in large part, dependent upon providing the appropriate volume to gap 160, it is desirable to accurate align template 22 and substrate 158. To that end, template 22 includes template alignment marks, one of which is shown as 162, and substrate 158 includes substrate alignment marks, one of which is shown as 164.
In the present example it is assumed that desired alignment between template 22 and substrate 158 occurs upon template alignment mark 162 being in superimposition with substrate alignment mark 164. As shown, desired alignment between template 22 and substrate 158 has not occurred, shown by the two marks be offset, a distance O. Further, although offset O is shown as being a linear offset in one direction, it should be understood that the offset may be linear along two directions shown as O1 and O2. In addition to, or instead of, the aforementioned linear offset in one or two directions, the offset between template 22 and substrate 158 may also consist of an angular offset, shown in
Referring to
After the desired alignment has occurred, actuators 40, 42, and 44 are operated to move template 22 into contact with a surface proximate to substrate. In the present example surface consists of polymerizable imprinting material 166 disposed on substrate 158. It should be noted that actuators 40, 42, and 44 are operated to minimize changes in the angle formed between neutral axes A and B once desired alignment has been obtained. It should be known, however, that it is not necessary for neutral axes A and B to extend exactly parallel to one another, so long as the angular deviation from parallelism is within the compliance tolerance of compliant device 18, as defined by flexure joints 62, 64, 66, and 68 and flexure arms 54, 56, 58, and 60. In this fashion, neutral axes A and B may be orientated to be as parallel as possible in order to maximize the resolution of pattern formation into polymerizable material. As a result, it is desired that position 122 at which the first and second RCCs are situation be placed at the interface of template 22 and material.
Referring to
Referring to
Upon contact with material 166, it is desired that portion 180 of material 166 in superimposition with projections 30 remain having a thickness t1, and sub-portions 182 remain having a thickness t2. Thickness t1 is referred to as a residual thickness. Thicknesses “t1” and “t2” may be any thickness desired, dependent upon the application. Thickness t1 and t2 may have a value in the range of 10 nm to 10 μm. The total volume contained material 166 may be such so as to minimize, or to avoid, a quantity of material 166 from extending beyond the region of substrate 158 not in superimposition with mold 172, while obtaining desired thicknesses t1 and t2. To that end, mesa 170 is provided with a height, hm, which is substantially greater than a depth of recesses 174, hr. In this manner, capillary forces of material 166 with substrate 158 and mold 172 restrict movement of material 166 from extending beyond regions of substrate 158 not in superimposition with mold 172, upon t1 and t2 reaching a desired thickness.
A benefit provided by system 10 is that it facilitates precise control over thicknesses t1 and t2. Specifically, it is desired to have each of thicknesses t1 be substantially equal and that each of thicknesses t2 be substantially equal. As shown in
The embodiments of the present invention described above are exemplary. As a result, many changes and modifications may be made to the disclosure recited above, while remaining within the scope of the invention. Therefore, the scope of the invention should not be limited by the above description, but instead should be determined with reference to the appended claims along with their full scope of equivalents.
The present application is a continuation-in-part of U.S. application Ser. No. 10/858,179, filed on Jun. 1, 2004, entitled “Compliant Device for Nano-Scale Manufacturing,” listing Byung-Jin Choi and Sidlgata V. Sreenivasan as inventors, and a divisional of U.S. Application No. (unassigned), Attorney Docket Number, P227M1I141, filed on even date herewith, entitled “Method and System to Control Movement of a Body for Nano-Scale Manufacturing,” listing Byung-Jin Choi and Sidlgata V. Sreenivasan as inventors.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 11142825 | Jun 2005 | US |
| Child | 11142838 | Jun 2005 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 10858179 | Jun 2004 | US |
| Child | 11142838 | Jun 2005 | US |
