METHOD OF SELF-ALIGNED FULLY INTEGRATED STCK FABRICATION
The embodiments disclose a method of self-aligned fully integrated stack fabrication that includes writing fully integrated self-aligned data and servo two dimensional low-frequency guiding patterns that include encoded servo-information to create various types of self-assembly low-frequency guiding structures, guiding high density self-assembly processes using the low-frequency guiding structures to create high density data and servo fields and etching the high density data and servo fields and low-frequency encoded servo-information into a template substrate to create fully integrated stack master templates to use in the fabrication of stacks such as bit patterned media.
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Bit patterned media (BPM) disk manufacturing includes fabricating master-templates. Fabricating master-templates includes nano-imprint lithography processes. Nano-imprint lithography includes self-assembly processes to create high density patterns. Self-assembly processes create regular patterns such as hexagonal close packed or square structures used for creating BPM data-patterns. Two or more pattern overlay processes are added to create BPM of servo-patterns. Overlay misalignments create inaccuracies in the master templates.
In a following description, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration a specific example in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present invention.
General Overview:It should be noted that the descriptions that follow, for example, in terms of a method of self-aligned fully integrated stack fabrication is described for illustrative purposes and the underlying system can apply to any number and multiple types of stacks and servo-information. In one embodiment the method of self-aligned fully integrated stack fabrication can be configured using numerous etching and guided self assembly processes. The method of self-aligned fully integrated stack fabrication can be configured to include large servo-field patterns that include servo information and can be configured to include small servo-field patterns that include servo information using the present invention.
The low-frequency data-field and larger servo information guiding structures are combined into one integrated set of guiding patterns to avoid using overlays of separate data and servo patterns which may cause inaccuracies during the stack fabrication process. The combined integrated set of guiding patterns enables encoding servo information into the low-frequency servo-field patterns at the same time for transfer into the stack during fabrication of one embodiment.
A process is used to etch low-frequency guiding patterns into an imprint substrate to imprint a resist layer deposited on an image layer 110. The imprinted resist layer is used to transfer the low-frequency guiding patterns into the image layer deposited onto a template substrate 120. A single or multi-layered image layer is deposited onto the template substrate. A wet reverse-tone process or a dry reverse-tone process is used to transfer the low-frequency guiding patterns into the image layer.
The processes continue to use the low-frequency guiding patterns to guide a self-assembly process to create a high-frequency background 130. The guided self-assembly process creates a high-frequency background in the data-fields and at the same time creates high-frequency background servo-fields that include the low-frequency encoded servo information. The concurrently created fully integrated data and servo fields can be effectively planarized of one embodiment.
In another embodiment a direct-etch process is used to transfer the low-frequency guiding patterns directly into the image layer. A subsequent guided self-assembly process is used to create a high-frequency background of the data-fields and at the same time create the low-frequency encoded servo-fields of one embodiment.
The method of self-aligned fully integrated stack fabrication continues with a process to etch the high-frequency data and servo fields and low frequency servo information into the template substrate 140. The etched substrate including the high-frequency data patterns and the low frequency servo patterns forms a fully integrated stack fabrication master template 150 of one embodiment.
DETAILED DESCRIPTION Low-Frequency Guiding Patterns:The master-template 212 is formed using a substrate 230 using a material such as quartz 232 or silicon 234. The next step is to deposit an image layer 220 onto the substrate 230. The image layer may include a single-layer image layer 222 using materials such as chromium (Cr) 224 or amorphous carbon (a-C) 226. The image layer may include a multi-layer image layer 228. The next process step is to deposit a resist layer 215 onto the image layer. The description of the processes continues in
In another embodiment e-beam lithography of low-frequency guiding patterns 236 can be used to transfer the guiding patterns to the resist layer. E-beam lithography by emitting a beam of electrons following the low-frequency guiding patterns exposes the resist layer. An e-beam lithography exposed resist layer 238 can be developed by removing for example the non-exposed areas of the resist layer materials which for example can be removed using a chemical etching process of one embodiment.
The transfer of the low-frequency guiding patterns using processes such as the imprint template or e-beam lithography form the topography of the low-frequency guiding patterns in the resist layer on top of the image layer 244 and substrate 230. In one embodiment a direct-etch process 250 using a process such as ion beam etching 253 is used to etch low-frequency patterns into image layer 254 directly. In another embodiment a reverse-tone process 260 is performed using a wet reverse tone process 262 or dry reverse tone process 264 to transfer the low-frequency guiding patterns into image layer 244. A continuation of the processing is shown in
Guided Self-Assembly Process:
The process continues with a step to etch patterns into substrate 280. The etching transfers the high-frequency data-field patterns 282 and the low frequency servo information encoded servo-field patterns in a high frequency background 284 into the substrate material. The remaining portions of the layers deposited on the substrate are removed and the etched substrate cleaned. The remaining etched substrate forms a fully integrated stack fabrication master template 150. The method of self-aligned fully integrated stack fabrication can be used to produce a bit-patterned stack fabrication master template 290 or any other patterned stack fabrication master template 292 of one embodiment.
Low-Frequency Large Servo-Field Guiding Patterns:The combined fully integrated low-frequency two dimensional guiding patterns 300 also include low-frequency large servo-field guiding patterns 320. The low-frequency large servo-field guiding patterns 320 are chosen to be compatible with the natural patterns create by the traditional sparse hexagonal guiding structures for the data-fields. A process to encode servo-information 206 into the low-frequency large servo-field guiding patterns 320 can be used to pattern the servo-information into a stack during the fabrication process. The combined fully integrated low-frequency two dimensional guiding patterns 300 avoids overlaying separate data-field and servo-field patterns which may cause inaccuracies due to miss-positioning of the overlays of one embodiment.
High-Frequency Large Servo-Field Master Template:The process proceeds to spin a resist layer onto the image layer 425. The low-frequency large servo field guiding patterns are etched into a substrate to create a low-frequency large servo field guiding patterns imprint template 430. The resist layer 420 is used to imprint the low-frequency large servo field guiding patterns. The next step in the imprinting process is to set low-frequency large servo field guiding patterns imprint template into resist layer 435 of one embodiment.
An ultraviolet (UV) light source 440 is used to project ultraviolet (UV) light through the low-frequency large servo field guiding patterns imprint template 430 to the resist layer. The resist through capillary action fills the cavities of the low frequency guiding patterns. The process to use ultraviolet (UV) light to cure resist 445 material sets the low-frequency large servo field guiding patterns into the resist to form an imprinted resist layer 460. A process to lift the low-frequency large servo field guiding patterns imprint template from the imprinted resist layer 450 is completed to reveal the imprinted resist layer 460. The continuation of the processes is described in
The spun HSQ 510 hardens and then is planarized. A HSQ etch-back 525 is used to planarize the HSQ 510. The planarization of the HSQ is achieved using processes such as chemical etching or mechanical planarization. The planarized HSQ 520 matches the upper surface level of the imprinted resist layer 460. An etch-back to remove imprinted resist 535 is processed to reveal the reverse tone planarized HSQ 520. Subsequent processes are described in
Continuing from the processes described in
A high frequency guided self-assembly process 160 is used to spin poly styrene-poly dimethylsiloxane (PS-PDMS) and anneal 650 the material to harden the high density structures. The highest portions of the high density structures consist of poly styrene (PS) 660. A chemical process is used to etch-back PS 670. The etched chromium (Cr) image layer 640 and remaining high frequency PDMS structures form a mask in subsequent etching processes. Processes described in
The etched quartz substrate 760 forms the large servo-field high-frequency master template 330. The low frequency large servo information encoded servo field patterns in a high frequency background 340 and high-frequency data field patterns 282 form the fully integrated stack fabrication master template 150. The use of the method of self-aligned fully integrated stack fabrication produces a highly accurate fully integrated stack fabrication master template 150 to fabricate bit-patterned stacks and any other patterned stack media of one embodiment.
Low-Frequency Small Servo-Field Guiding Patterns:The combined fully integrated low-frequency two dimensional guiding patterns 800 also include low-frequency small servo-field guiding patterns 810. The low-frequency small servo-field guiding patterns 810 illustrated are chosen to be compatible with the natural patterns create by the square guiding structures for the data-fields. A process to encode servo-information 206 into the low-frequency small servo-field guiding patterns 810 can be used to pattern the servo-information into a stack during the fabrication process of one embodiment.
High-Frequency Small Servo-Field Master Template:A low-frequency small servo guiding patterns imprint template 940 is created by etching the low-frequency small servo guiding patterns into a substrate. The transfer process proceeds to spin resist layer onto image layer 425. The next step is to set low-frequency small servo field guiding patterns imprint template into resist 930. The resist layer 950 through capillary action fills the cavities of the low frequency guiding patterns of one embodiment.
An ultraviolet (UV) light source 440 is used to project ultraviolet (UV) light through the low-frequency small servo guiding patterns imprint template 940 to the resist layer 950. The process to use ultraviolet (UV) light to cure resist 445 material sets the low-frequency small servo field guiding patterns into the resist to form an imprinted resist layer 970. A process to lift the low-frequency small servo guiding patterns imprint template 940 from the resist layer 950 is completed to reveal the imprinted resist layer 970 and portions of the surface of the amorphous-carbon (a-C) image layer 920. The continuation of the processes is described in
A process proceeds to spin hydrogen silsesquioxane (HSQ) 515 over the imprinted resist layer 970 and exposed surfaces of the amorphous-carbon (a-C) image layer 920. The spun HSQ 510 reaches a level above the imprinted resist layer 970. A HSQ etch-back 525 lowers the level of the etched HSQ 520 to match the level of the imprinted resist layer 970 of one embodiment.
An etch-back to remove imprinted resist 535 exposes HSQ small servo mask 1010 and HSQ low-frequency data mask 1000 structures. The mask structures leave portions of the surface of the amorphous-carbon (a-C) image layer 920 exposed. Processing continues as described in
The upper sections of the PS-PDMS structures include polymethylsiloxane (PDMS) 1105 and the lower sections include polystyrene (PS) 1110. The high density PS-PDMS structures set between the HSQ small servo mask 1010 and HSQ low-frequency data mask 1000 structures. The masks on the amorphous-carbon (a-C) image layer 920 are used in an etching process of the image layer of one embodiment.
An ion beam etching process 600 etches into a-C image layer 1140. The etching is followed by processes to remove PS-PDMS and HSQ 1145. The removal of the HSQ small servo mask 1120, HSQ data mask 1125 and PS-PDMS data mask 1130 exposes the etched a-C image layer high frequency data mask 1150 and etched a-C image layer low frequency small servo mask 1160. Processes continue as described in
The etched silicon substrate 1215 includes the high frequency data patterns and low frequency small servo patterns 820. The etched silicon substrate 1215 forms the small servo-field high-frequency master template 1220. The low frequency small servo information encoded servo field patterns in a high frequency background 830 of
The foregoing has described the principles, embodiments and modes of operation. However, the invention should not be construed as being limited to the particular embodiments discussed. The above described embodiments should be regarded as illustrative rather than restrictive, and it should be appreciated that variations may be made in those embodiments by workers skilled in the art without departing from the scope as defined by the following claims.
Claims
1. A method of self-aligned fully integrated stack fabrication, comprising:
- writing fully integrated self-aligned data and servo two dimensional low-frequency guiding patterns that include encoded servo-information and configured to create various types of self-assembly low-frequency guiding structures;
- guiding high density self-assembly processes using the low-frequency guiding structures and configured to create high density data and servo fields; and
- etching the high density data and servo fields and low-frequency encoded servo-information into a template substrate and configured to create fully integrated stack master templates.
2. The method of claim 1, wherein the self-assembly low-frequency guiding structures include various types of structures such as hexagonal close packed and square guiding structures and configured to create low-frequency data and servo fields.
3. The method of claim 2, wherein servo-field low-frequency guiding structures are larger than data-field low-frequency guiding structures and are configured to be compatible with self-assembly long-range order natural patterns.
4. The method of claim 1, further comprising depositing a resist layer on an image layer deposition on the template substrate and imprinting the resist layer with the self-aligned fully integrated data and servo two dimensional low-frequency guiding patterns.
5. The method of claim 1, wherein various low-frequency patterned self-assembly guiding structures created in the imprinted resist layer are transferred to the image layer using transfer processes such as a wet reverse-tone process and a dry reverse-tone process.
6. The method of claim 1, wherein the image layer deposition onto the template substrate is configured to include single layer and multi-layered image layers using materials such as chromium and amorphous carbon.
7. The method of claim 1, further comprising using a direct-etch process to transfer directly into the image layer the self-aligned fully integrated data and servo two dimensional low-frequency guiding patterns.
8. The method of claim 1, wherein the guided self-assembly process includes using various self-assembling agents such as poly styrene-poly dimethylsiloxane (PS-PDMS), polystyrene polymethyl methacrylate (PS-PMMA), polystyrene-polyethylene oxide (PS-PEO) and any other suitable self-aligning agents.
9. The method of claim 8, wherein the high density self-assembly process creates a high-frequency background on the image layer enabling effective planarization.
10. The method of claim 1, wherein the template substrate includes the use of materials such as quartz and silicon.
11. The method of claim 1, wherein etching the high density data and servo fields and low-frequency encoded servo-information into the template substrate is a single process avoiding overlays and includes the use of e-beam lithography.
12. The method of claim 1, further comprising using various combinations of processes such as e-beam lithography, guided self-assembly processes and direct-etch processes using the two dimensional low-frequency guiding patterns to create a fully integrated stack fabrication master template.
13. An apparatus, comprising:
- means for writing self-aligned data and servo two dimensional low-frequency guiding patterns that includes encoded servo-information; and
- means for fully integrating various compatible two dimensional low-frequency self-assembly guiding structures created using the self-aligned data and servo two dimensional low-frequency guiding patterns, wherein the fully integrated compatible two dimensional low-frequency self-assembly guiding structures are used in processes to pattern stack master-templates.
14. The apparatus of 13, further comprising means wherein the low-frequency data-field guiding patterns are written to create natural patterned guiding structures such as sparse hexagonal and wherein the low-frequency servo-field guiding patterns are written to create guiding structures compatible with the low-frequency data-field natural patterned guiding structures.
15. The apparatus of 13, further comprising means for encoding servo-information into the low-frequency large servo-field guiding pattern structures.
16. The apparatus of 13, further comprising means for concurrent etching of the low-frequency data-field patterns and low-frequency large servo-field guiding patterns into a single nano-imprint template.
17. A fully integrated stack patterning system, comprising:
- compatible fully integrated self-aligned data and servo two dimensional low-frequency guiding patterns written and configured to include encoded servo-information;
- various types of compatible self-assembly low-frequency guiding structures created using the two dimensional low-frequency guiding patterns; and
- high density data and servo field structures created using a self-assembly process guided by the low-frequency guiding structures, together with the low-frequency encoded servo-information structures are etched into a substrate and configured to create a patterned fully integrated stack fabrication master template.
18. The fully integrated stack patterning system of claim 17, wherein the data two dimensional low-frequency guiding patterns include natural patterns configured to create low-frequency data guiding structures such as sparse hexagonal guiding structures.
19. The fully integrated stack patterning system of claim 17, wherein the servo two dimensional low-frequency guiding patterns are configured to create low-frequency servo guiding structures that are larger than and compatible with the natural patterns of the low-frequency data guiding structures.
20. The fully integrated stack patterning system of claim 17, wherein the high density data and servo field structures including the low-frequency encoded servo-information structures are planarized.
Type: Application
Filed: Jan 31, 2012
Publication Date: Aug 1, 2013
Applicant: SEAGATE TECHNOLOGY, LLC (Cupertino, CA)
Inventor: René Johannes Marinus Van de Veerdonk (Pleasanton, CA)
Application Number: 13/363,039
International Classification: C25F 3/00 (20060101); C23F 1/00 (20060101);