WO2022031404A1

WO2022031404A1 - Apparatus and method for making seamless soft stamps

Info

Publication number: WO2022031404A1
Application number: PCT/US2021/041246
Authority: WO
Inventors: Arvinder Chadha; Manivannan Thothadri
Original assignee: Applied Materials, Inc.
Priority date: 2020-08-03
Filing date: 2021-07-12
Publication date: 2022-02-10
Also published as: EP4189485A1; TW202212966A; KR20230044281A; JP2023537471A; CN116056866A

Abstract

The present disclosure provides for an imprint lithography apparatus including a backing plate, and one or more masters coupled to the backing plate. Each of the masters includes a base coupled to the backing plate, and at least one mesa structure extending from the base. Each mesa structure includes features disposed thereon. The imprint lithography apparatus is capable of producing stamps used to further pattern devices, or the imprint lithography apparatus is capable of producing devices. The stamps and devices produced from the imprint lithography apparatus is substantially free of defects associated with seams that are disposed between adjacent masters.

Description

APPARATUS AND METHOD FOR MAKING SEAMLESS SOFT STAMPS

BACKGROUND

Field

[0001] Embodiments of the present disclosure generally relate to systems and methods of manufacturing a semiconductor device. More particularly, the present disclosure is directed to apparatuses and methods for making seamless soft stamps.

Description of the Related Art

[0002] Imprint lithography is a contact patterning method that can be used to fabricate nanometer scale patterns. Generally, imprint lithography begins by creating a template of a pattern. An imprint material, such as a resin, is deposited on the substrate to be patterned. Then, the patterned template is pressed against the imprint material to imprint the pattern into the substrate. The imprint material is then cured to solidify the patterning in the resin on the substrate.

[0003] However, conventional imprint lithography methods and apparatus have various challenges. For example, conventional imprint lithography methods with nanofeatures are not suitable for large area substrates (greater than 300 mm), such as display devices, because conventionally used masters are not large enough to pattern large area displays. As such, some conventional imprint methods have used multiple masters, which have been adhered to one another. However, a seam is formed between the masters, which is then transferred into the patterning on the substrate. The patterned irregularities are caused by the seams between masters and also at the periphery of masters. Irregularities can cause decreased device efficiency and even device failure. Large imprint substrates are prepared by aligning and imprinting multiple masters simultaneously or sequentially. The regions between adjacent masters (e.g., seams) and the regions at the periphery of each of the masters can also create irregularities on the imprint substrate that affect performance of the device, such as a visual defect. For example, in the case of a light guided panel (LGP), when a seam is imprinted into the LGP, the seam becomes a surface feature that could direct, scatter or out-couple light out of the LGP. In the case of liquid crystal display (LCD), when a seam is imprinted into the LCD, the viewer will see visual defects arising from the seam in the display.

[0004] Therefore, there is a need for imprint lithography methods and apparatuses that can be used to imprint large area substrates to produce patterns substantially free irregularities corresponding to seams and periphery regions of masters.

SUMMARY

[0005] In an embodiment, an imprint lithography apparatus is provided, including a backing plate, and one or more masters coupled to the backing plate. Each of the masters includes a base coupled to the backing plate, and at least one mesa structure extending from the base. Each mesa structure includes features disposed thereon.

[0006] In another embodiment, an imprint method includes imprinting features of an imprint lithography apparatus into an imprint material disposed on a surface of a substrate. The imprint lithography apparatus including a backing plate and one or more masters coupled to the backing plate. Each of the masters include a base coupled to the backing plate, and at least one mesa structure extending from the base. Each mesa structure includes features disposed thereon. The imprint material is subjected to a cure process. The imprint lithography apparatus is released from the imprint material.

[0007] In another embodiment, an imprint lithography apparatus is provided, including a backing plate and one or more masters coupled to the backing plate. Each of the masters include a base coupled to the backing plate, and at least one mesa structure extending from the base, each mesa structure having features disposed thereon. The imprint lithography apparatus has a width of at least 25 mm and a length of at least 25 mm.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. [0009] FIGS. 1A and 1 B depict schematic, cross-sectional views of various imprint lithography apparatuses according to embodiments of the present disclosure.

[0010] FIGS. 1 C-1 E depict a schematic, cross-sectional view of an imprint lithography apparatus and various imprint materials on a substrate having various imprint material thickness in accordance with an embodiment of the present disclosure.

[0011] FIG. 1 F depicts a schematic, cross-sectional view of an imprint lithography apparatus according to an embodiment of the present disclosure.

[0012] FIG. 2 depicts a schematic bottom view of an imprint lithography apparatus in accordance with an embodiment of the present disclosure.

[0013] FIG. 3A-3C depicts a top view of an imprint substrate at various stages of imprinting with an imprint lithography apparatus in accordance with an embodiment of the present disclosure.

[0014] FIG. 4 depicts a flow diagram of an imprint method in accordance with an embodiment of the present disclosure.

[0015] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.

[0016] It is to be noted, however, that the appended drawings illustrate only exemplary embodiments of this disclosure and are therefore not to be considered limiting of its scope, for the disclosure may admit to other equally effective embodiments.

DETAILED DESCRIPTION

[0017] Before describing embodiments of the present disclosure, it is to be understood that the present disclosure is not limited to the details of construction or methods set forth in the following description. The present disclosure is capable of other embodiments and of being practiced or being carried in various ways. [0018] Embodiments of the present disclosure generally relate to imprint lithography, and more particularly to methods and apparatuses for creating a large area imprint without a seam. An imprint lithography apparatus is provided having a backing plate, and one or more masters coupled to the backing plate. Each of the masters includes a base coupled to the backing plate, and at least one mesa structure extending from the base. Each mesa structure includes features disposed thereon.

[0019] The embodiments that follow will refer to methods and apparatuses for creating a large area imprint without a seam. The embodiments are useful for imprinting other materials in other applications with seam-like challenges at the periphery of the master, stamp or display device.

[0020] FIGS. 1A and 1 B depicts a schematic, cross-sectional view of an imprint lithography apparatus (e.g., 100A, 100B) according to an embodiment of the present disclosure. The imprint lithography apparatus (e.g., 100A, 100B) is used to pattern substrates by imprinting a material disposed on the substrate using features disposed on the imprint lithography apparatus (e.g., 100A, 100B), curing the material that has been imprinted, and releasing the imprint lithography apparatus (e.g., 100A, 100B) from the material to produce an imprinted material. The imprinted material is a stamp used to further imprint other devices, alternatively, the imprinted material is a film over a display device. The imprint lithography apparatus (e.g., 100A, 100B) includes a complementary pattern with respect to the imprinted material. In some embodiments, which can be combined with other embodiments described herein, the imprinted material is a stamp with a negative pattern with respect to the pattern on the imprint lithography apparatus. Furthermore, the imprint lithography apparatus has a positive pattern with respect to the negative pattern of the stamp and a positive pattern with respect to the positive pattern of the device to be imprinted with the stamp. In some embodiments, which can be combined with other embodiments described herein, the imprinted material is a display device and the device has a complementary pattern with respect to a negative pattern of the imprint lithography apparatus 100A, 100B.

[0021] As shown in FIG. 1A, an imprint lithography apparatus 100A includes a backing plate 104 and master(s) (e.g., 102A, 102B, collectively 102) coupled to the backing plate 104. Each of the masters 102 include a base 108 coupled to the backing plate 104 and at least one mesa structure 106 extending from the base 108, each mesa structure 106 having features 112 disposed thereon. The backing plate 104 is composed of glass, aluminum, stainless steel, quartz, polymer, or combinations thereof. The backing plate 104 has a thickness of about 100 pm, such as about 100 pm to about 500 pm. Each of the masters 102 is composed of silicon, Periodic Group lll-V materials, glass, polymer, or combinations thereof. In some embodiments, which can be combined with other embodiments described herein, adjacent masters are separated by seams 114.

[0022] In some embodiments, which can be combined with other embodiments described herein, the mesa structures 106 are equidistant from one another. The mesa spacing is defined by the spacing between the center of a mesa structure to the center of an adjacent mesa structure. Although the figures depict the mesa structures 106 having equal distance between one another, it is also contemplated that the mesa structures have different spacing between adjacent mesa structures. Similarly, the mesa structures are identical in dimensions and pattern features, alternatively, the mesa structures differ in dimensions and in pattern features. In some embodiments, which can be combined with other embodiments described herein, one or more masters 102 are coupled to the backing plate 104. The masters 102 are coupled to the backing plate 104 using a bonding material 105 or vacuum adhesion. The bonding material is a continuous bonding material (e.g., as shown in FIG. 1A), or the bonding material is a discontinuous bonding material (e.g., as shown in FIG. 1 B). A continuous bonding material 105, as shown in Figure 1A, is deposited over substantially the entire surface area of the backing plate 104. A discontinuous bonding material 105A, 105B, as shown in Figure 1 B, is deposited selectively at each interface between each master 102 and the backing plate 104 (e.g., 105A), or is deposited intermittently over the surface area of the backing plate (e.g., 105B). In some embodiments, which can be combined with other embodiments described herein, the bonding material is one or more of a hydrocarbon based material, such as benzocyclobutene (BCB), a multicomponent UV-sensitive negative photoresist based on epoxy resin, gamma butyrolactone and triaryl sulfonium salt (e.g., SU8), thermoset, thermoplastic, low shrinkage adhesive, epoxy with low coefficient of thermal expansion (CTE), silicon rubbers, epoxies, acrylate urethane, and combination(s) thereof. [0023] Although the figures depict two masters 102A, 102B on the backing plate 104, it is also contemplated that a single master or more than two masters may be disposed on the backing plate 104 depending on the application or use of the imprint lithography apparatus 100A, 100B. In some embodiments, which can be combined with other embodiments described herein, the imprint lithography apparatus includes an array of masters, such as a two by one array or larger, such as a two by two array or larger, such as a four by three array, such as an 8 by 5 array of masters. Each master includes a width of about 25 mm to about 3 m, such as about 50 mm to about 2 m, such as about 50 mm to about 100 mm. Each master includes a length of about 25 mm to about 3 m, such as about 50 mm to about 2 m, such as about 50 mm to about 100 mm. Each master 102 includes at least a single mesa structure 106, as shown in FIG. 1 B, or a plurality of mesa structures 106, as shown in FIG. 1A. A cross- sectional top view of the master can be any shape such as circular, rectangular, square, and other geometries depending on the application of the imprint lithography apparatus.

[0024] Referring back to FIG. 1A, each mesa structure 106 includes a base interface portion 108 having a mesa height 111 and a pattern portion (e.g., including features 112) having a pattern height 113. Each mesa structure 106 includes a mesa ratio of mesa height 111 to pattern height 113 of about 5000:1 to about 1 :1 , such as about 1000:1 , such as about 500:1. The pattern height 113 is about 10 nm to about 50 pm, such as about 10 nm to about 1 pm, such as about 100 nm to about 1 pm, such as about 500 nm to about 1 pm. In some embodiments, which can be combined with other embodiments described herein, the mesa height 111 is about 1 pm to about 100 pm, such as about 1 pm to about 25. Each mesa structure 106 includes a mesa width. The mesa width is about 5 pm to about 50 mm, such as about 5 pm to about 50 pm, or about 100 pm to about 200 pm, or about 10 mm to about 25 mm. In some embodiments, which can be combined with other embodiments described herein, the base 108 includes a base thickness 109 of about 25 pm to about 3 mm, such as about 25 pm to about 50 pm. A ratio of base thickness 109 to mesa height 111 is 25:1 or greater, such as 30:1 or greater.

[0025] Each feature 112 of the mesa structure 106 includes a width of about 10 nm to about 500 nm, such as about 20 nm to about 300 nm. The width of each feature 112 corresponds to a width of display features of the display to be imprinted with the imprint lithography apparatus or with a stamp produced from the imprint lithography apparatus. Each feature has a binary, or non-binary geometry. In some embodiments, which can be combined with other embodiments described herein each feature includes a cross-sectional shape including one or more of a circle, a rectangle, an asymmetric slant, a blazed shape, and combinations thereof.

[0026] FIGS. 1 C-1 E depict a schematic, cross-sectional view of an imprint lithography apparatus 100C and various imprint materials of imprint substrates 130A, 130B, 130C having various imprint material thickness 121 in accordance with an embodiment of the present disclosure. The features 112 of the imprint lithography apparatus 100C is contacted with an imprint material 120 disposed on a substrate 118 having various imprint material thicknesses 121. In some embodiments, which can be combined with other embodiments described herein, the imprint material thickness 121 of the imprint substrate 130A is greater than the pattern height 113 of the pattern portion (e.g., the features 112), as shown in FIG. 1 C. Alternatively, the imprint material thickness 121 of the imprint substrate 130B is substantially equal to the pattern height 113, as shown in FIG. 1 D. Alternatively, the imprint material thickness 121 of the imprint substrate 130C is less than the pattern height 113, as shown in FIG. 1 E. The pattern height 113 is at least two times greater than the thickness 121 of the imprint 130C. In the embodiments depicted in FIG. 1 C and FIG. 1 D, the base interface portions 110 of the mesa structures 106 are in contact with the imprint material. In the embodiments depicted in FIG. 1 E, the base interface portions 110 of the mesa structures 106 are spaced away from the imprint material.

[0027] Conventional masters do not have mesa structures 106 having base interface portions 110. Instead, features of conventional masters are dispose directly on a master base, and seams similar to the seams 114 depicted in FIGS. 1 A-1 E are present between masters which create defects, such as bumps and/or dents in the imprint substrate during imprinting of adjacent masters. Although a filler can be used to reduce issues with seam formation, the seams can be under filled producing a concave area, or the seams can be over filled to form a convex area. Under and/or over filling seams can produce defects resulting in visual defects. Similarly, defects are also formed using conventional masters even without seams, such as in conventional single masters. In this case, defects are formed between imprint locations using methods in which each master is used to imprint an imprint substrate sequentially or simultaneously. It has been found that the base interface portions 110 of the mesa structures 106 in accordance with the present disclosure prevents defects because it spaces the seam areas 114 away from the imprint material 120. In some embodiments, which can be combined with other embodiments described herein, the base interface portion 110 and the pattern portion (e.g., features 112) of the mesa structures 106 are integral with one another. Alternatively, as shown in FIG. 1 F, the pattern portion includes a residual layer 140 which is disposed between the base interface portion 110 and the features 112. The residual layer 140 and the features 112 are composed of a pattern portion material that is different from the composition of the base interface portion 110. The pattern portion is composed of TiN, TaN, Nb20s, SiN, SiCN, SiC>2, SiCN, SiCON, VaO, or combination(s) thereof.

[0028] FIG. 2 depicts a schematic bottom view of an imprint lithography apparatus 200 in accordance with an embodiment of the present disclosure. The imprint lithography apparatus 200 depicts an array of masters (collectively 202) on a backing plate 204. Although each master 202(1 ,1 ), 202(1 ,2), 202(1 ,3), 202(2,1 ), 202(2,2), 202(2,3) is depicted to be rectangular and similar in size, it is also contemplated that each master have different shapes and sizes. Additionally, each of the masters include a base 208, each base 208 includes the same or different mesa structures 210, and each mesa structure 210 includes the same or different features 212. For illustrative purposes, the master 202(1 ,1 ) is depicted to correspond to the master 102A depicted in FIG. 1A, and the master 202(2,1 ) is depicted to correspond to the master 102B depicted in FIG. 1A. Further, masters 202(1 ,2) and 202(2,2) are depicted to correspond to the masters that are used to imprint the imprint substrate 330 shown in FIGS. 3A to 3C.

[0029] FIGS. 3A-3C depicts a top view of an imprint substrate 330 at various stages of imprinting with an imprint lithography apparatus in accordance with an embodiment of the present disclosure. The imprint substrate 330 includes imprint areas 302(1 ,1 ), 302(1 ,2), 302(1 ,3), 302(2,1 ), 302(2,2), and 302(2,3). FIGS. 3A-3C can be described with reference to the method 400 provided in FIG. 4. The imprinted substrate shown in FIG. 3A is produced using an imprint lithography apparatus in accordance with the present disclosure, such as an imprint lithography apparatus having a single master, or an imprint lithography apparatus having two masters. As described in operation 402, the features of the imprint lithography apparatus is imprinted into the imprint material disposed on a surface of the substrate. The imprints are shown in imprint areas 302(1 ,1 ) and 302(2,1 ). Both of the imprint areas are imprinted simultaneously with an imprint lithography apparatus having two masters. Alternatively, each of the imprint areas are imprinted sequentially with an imprint lithography apparatus having a single master disposed thereon. Alternatively, each of the imprint areas are imprinted sequentially with two different imprint lithography apparatuses, each having a single master disposed thereon. In operation 404, the imprint areas are subjected to a cure process. The cure process is a local cure process on the imprinted areas, and does not cure the areas that have not been imprinted. Local cure processes can use any cure process known in the art, such as positioning a mask between the light source and the substrate to prevent UV light from reaching certain portions of the substrate. In some embodiments, which can be combined with other embodiments described herein, the cure process uses electromagnetic energy, such as ultraviolet light to expose the imprint material. The imprint material is exposed to the energy from below the substrate, such as for transparent substrates, or the imprint material is exposed to the energy from above the imprint material, such as for transparent imprint lithography apparatuses. The substrate is composed of glass, quartz, polymer, or combinations thereof. In operation 406, the imprint lithography apparatus is released from the imprint material. The method 400 is repeated to produce the imprint 300B as depicted in FIG. 3B, and again to produce imprint 300C as depicted in FIG. 3C. Similar to imprint 300A, imprint 300B is produced using one to four imprint lithography apparatuses, each having one to four masters. The imprint areas are formed sequentially with respect to one another, or simultaneously with respect to one or more imprint areas. Imprint 300C depicted in FIG. 3C is produced using one to six imprint lithography apparatuses, each having one to six masters. The imprint areas are formed sequentially with respect to one another, or simultaneously with respect to one or more imprint areas. In some embodiments, which can be combined with other embodiments described herein, a single imprint lithography apparatus is used to imprint a large area substrate such as a substrate with a width of about 1 m to about 3 m and a length of about 1 m to about 3 m. It is also contemplated to use a combination of imprint lithography apparatuses of the present disclosure, and stamps produced therefrom to pattern final devices.

[0030] The final imprinted substrate is formed into a stamp which can be used to pattern one or more devices, or the imprint substrate can be formed into a display device. The stamp comprises one or more of poly-di-methyl siloxane, photopolymer, oligomeric materials, acrylates, silicones, thermoplastic adhesives, elastomeric adhesives, thermally-cured acrylate, a UV-cured acrylate, sol-gels with organic matrix interspersed, sol-gels distributed with inorganic nano-particles, sol-gels with nanoparticles embedded as fillers or covalently bonded to the organic matrix, or combination(s) thereof. The presently disclosed methods and apparatuses are useful to produce liquid crystal displays (LCDs), light guide plates (LGPs), light field plates (LFPs), and wire grid polarizers (WGPs), in addition to other display device and other optical elements of films for other applications including augmented reality displays and/or eyepieces, 3-dimensional displays, virtual reality displays or eyepieces.

[0031] In summation, an imprint lithography apparatus is provided, including an imprint lithography apparatus, including a backing plate, and one or more masters coupled to the backing plate. Each of the masters includes a base coupled to the backing plate, and at least one mesa structure extending from the base portion. Each mesa structure includes features disposed thereon. The imprint lithography apparatus is capable of producing stamps used to further pattern devices, or the imprint lithography apparatus is capable of producing devices. The stamps and devices produced from the imprint lithography apparatus is substantially free of defects associated with seams that are disposed between adjacent masters.

Claims

What is claimed is:

1 . An imprint lithography apparatus, comprising: a backing plate; and one or more masters coupled to the backing plate, each of the masters comprising: a base coupled to the backing plate; and at least one mesa structure extending from the base, each mesa structure having features disposed thereon.

2. The imprint lithography apparatus of claim 1 , wherein each mesa structure comprises a base interface portion having a mesa height and a pattern portion having a pattern height, each pattern portion comprising features, and each mesa structure comprising a mesa ratio of mesa height to pattern height of about 5000: 1 to about 1 :1.

3. The imprint lithography apparatus of claim 1 , wherein the one or more masters comprises a pair of adjacent masters having a seam therebetween.

4. The imprint lithography apparatus of claim 3, wherein a mesa structure of at least one of the pair of adjacent masters comprises a base interface portion having a mesa height and a pattern portion, wherein the seam is spaced away from the pattern portion by at least the mesa height.

5. The imprint lithography apparatus of claim 1 , wherein the at least one of base of at least one master comprises a plurality of mesa structures.

6. The imprint lithography apparatus of claim 5, wherein the plurality of mesa structures are spaced equidistant or non-equidistant from one another as determined by a distance from center to center of adjacent mesa structures of the plurality of mesa structures.

7. The imprint lithography apparatus of claim 5, wherein each mesa structure comprises features, wherein each mesa structure on a first master of the one or more masters comprises different features from one another.

8. The imprint lithography apparatus of claim 1 , wherein the master is bonded to the backing plate using a bonding material or adhesive or vacuum, wherein the master comprises silicon, Periodic Group lll-V materials, glass, polymer, or combinations thereof, and wherein the backing plate comprises glass, aluminum, stainless steel, quartz, polymer, or combinations thereof.

9. The imprint lithography apparatus of claim 1 , wherein the features of each mesa structure comprise: a width having a height of about 10 nm to about 500 nm; a feature diameter of about 10 nm to about 500 nm; and a cross-section geometry selected from a binary geometry, a non-binary geometry, a symmetric geometry, an asymmetric geometry, or combinations thereof.

10. An imprint method, comprising: imprinting features of at least one imprint lithography apparatus into an imprint material disposed on a surface of a substrate, each imprint lithography apparatus comprising: a backing plate; and one or more masters coupled to the backing plate, each of the masters comprising a base coupled to the backing plate, and at least one mesa structure extending from the base, each mesa structure having features disposed thereon; subjecting the imprint material to a cure process; and releasing each imprint lithography apparatus from the imprint material.

11 . The method of claim 10, wherein releasing each imprint lithography apparatus comprises forming a stamp, wherein the stamp comprises one or more of poly-di- methyl siloxane, photopolymer, oligomeric materials, acrylates, silicones, thermoplastic adhesives, elastomeric adhesives, thermally-cured acrylate, UV-cured acrylate, sol-gels or combination(s) thereof.

12. The imprint method of claim 10, wherein each mesa structure comprises a base interface portion having a mesa height and the features disposed on the base interface portion having a pattern height, wherein the imprint material has an imprint material thickness.

13. The imprint method of claim 12, wherein the imprint material thickness is less than the pattern height of the features.

14. The imprint method of claim 10, wherein releasing each imprint lithography apparatus from the imprint material forms a stamp, wherein the stamp is capable of imprinting a display film, wherein a master pattern of each imprint lithography apparatus corresponds to a positive pattern relative to a display pattern of the display and a stamp pattern corresponds to a negative pattern relative to the display pattern.

15. The imprint method of claim 14, wherein the stamp has a width of about 50 mm to about 3 m and a length of the about 50 mm to about 3 m.

16. The imprint method of claim 10, wherein the substrate is a display, wherein a master pattern of each imprint lithography apparatus corresponds to a negative pattern relative to a display pattern of the display.

17. The imprint method of claim 10, wherein the substrate comprises a plurality of imprint material portions, wherein each portion is imprinted, subjected to the cure process, and released simultaneously or sequentially using one or more of the at least one lithography apparatus.

18. An imprint lithography apparatus, comprising: a backing plate; and one or more masters coupled to the backing plate, each of the masters comprising: a base coupled to the backing plate; and at least one mesa structure extending from the base, each mesa structure having features disposed thereon, wherein the imprint lithography apparatus has a width of at least 25 mm and a length of at least 25 mm.

19. The imprint lithography apparatus of claim 18, wherein each mesa structure comprises a base interface portion having a mesa height and features disposed on the base interface portion with a pattern height, wherein the mesa height is about 10 nm to about 1 pm, and wherein the pattern height is about 1 pm to about 100 pm.

20. The imprint lithography apparatus of claim 18, wherein each features has a width of about 10 nm to about 500 nm, wherein the width of each feature corresponds to a width of display features of the display to be imprinted with the imprint lithography apparatus.