Method for forming patterned structure
By forming an oriented self-assembled layer on the photoresist layer and etching a second opening, the problem of pattern deviation caused by photoresist standing waves was solved, achieving high-quality patterning effects, especially in forming patterns with larger aspect ratios in semiconductor structures.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-07
- Publication Date
- 2026-03-27
AI Technical Summary
In existing technologies, standing waves in photoresist cause patterns to deviate from expectations during the formation of semiconductor structures, leading to problems such as increased pattern roughness, base plates, or undercutting, which affect the patterning effect.
A first phase and a second phase are separated on the photoresist layer using a directional self-assembled layer. A second opening is formed by etching to improve the pattern quality. The combination of the photoresist layer and the directional self-assembled layer is used as a mask for etching the target layer.
It improves the pattern resolution and aspect ratio, reduces pattern roughness, reduces foot or undercut, and ensures that the pattern meets expectations in the target layer.
Smart Images
Figure CN121752040A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present invention relates to a method of forming a patterned structure. BACKGROUND
[0002] Photoresists are used in semiconductor processes to form patterns. As the size of semiconductor structures becomes smaller, patterns with larger aspect ratios are more advantageous to improve performance and increase productivity. Thicker photoresists can help form patterns with larger aspect ratios. However, light used to pattern the photoresist can form standing waves in the photoresist, especially when the photoresist is too thick. The standing waves of light can cause the patterns formed in the photoresist to deviate from expectations, such as increasing the roughness of the patterns, causing the patterns to have footing or undercut, etc. Once the patterns formed in the photoresist are not as expected, the patterns formed in a target layer using the patterned photoresist also deviate from expectations. Therefore, it is necessary to develop a new method to pattern a structure. SUMMARY
[0003] The present invention provides a method of forming a patterned structure. The method includes the following operations. A photoresist layer on a target layer is patterned to form a first opening in the patterned photoresist layer. A directed self-assembly layer is formed on the patterned photoresist layer and in the first opening, wherein a directed self-assembly material in the directed self-assembly layer separates into a first phase on the patterned photoresist layer and a second phase in the first opening by being attracted by a degree of polarity of the patterned photoresist layer. The second phase is removed to form a second opening through the directed self-assembly layer. The target layer is etched through the second opening.
[0004] In some embodiments, the photoresist layer has a thickness of 80 nm to 120 nm.
[0005] In some embodiments, when the directed self-assembly layer is formed on the patterned photoresist layer, a total thickness of the patterned photoresist layer and a portion of the directed self-assembly layer on the patterned photoresist layer is 120 nm to 300 nm.
[0006] In some embodiments, when the directed self-assembly layer is formed on the patterned photoresist layer, a thickness of the portion of the directed self-assembly layer on the patterned photoresist layer is 10 nm to 180 nm.
[0007] In some embodiments, the patterned photoresist layer is polar to attract a polar end of the first phase, or the patterned photoresist layer is non-polar to attract a non-polar end of the first phase.
[0008] In some embodiments, the oriented self-assembly material includes a first portion having a first glass transition temperature and a second portion having a second glass transition temperature lower than the first glass transition temperature, and the first portion is adsorbed onto a patterned photoresist layer when the oriented self-assembly material separates into a first phase and a second phase.
[0009] In some embodiments, the oriented self-assembled layer is formed at a temperature between the first glass transition temperature and the second glass transition temperature.
[0010] In some embodiments, the oriented self-assembling material is a copolymer, and the copolymer is vertically arranged on the surface of the patterned photoresist layer.
[0011] In some embodiments, the first phase also includes a portion extending to the side of the patterned photoresist layer.
[0012] In some embodiments, the method further includes forming a hard mask layer on the target layer and forming a photoresist layer on the hard mask layer before patterning the photoresist layer.
[0013] The present invention also provides a method for forming a patterned structure. The method includes the following operations: patterning a photoresist layer on a target layer to form a first opening in the patterned photoresist layer; forming an oriented self-assembled layer on the patterned photoresist layer and in the first opening, wherein the oriented self-assembled material in the oriented self-assembled layer is separated into a first phase and a second phase by being attracted by the hydrophilicity of the patterned photoresist layer, the first phase covering the top surface of the patterned photoresist layer and the side surface of the first opening, and the first phase surrounding the second phase; removing the second phase to form a second opening through the oriented self-assembled layer; and etching the target layer through the second opening.
[0014] In some implementations, the thickness of the photoresist layer is 80 nm to 120 nm.
[0015] In some embodiments, when forming the oriented self-assembled layer on the patterned photoresist layer, the total thickness of the patterned photoresist layer and the portion of the oriented self-assembled layer on the patterned photoresist layer is 120 nm to 300 nm.
[0016] In some embodiments, when forming the oriented self-assembled layer on the patterned photoresist layer, the thickness of the portion of the oriented self-assembled layer on the patterned photoresist layer is from 10 nm to 180 nm.
[0017] In some embodiments, the patterned photoresist layer is hydrophilic to attract the hydrophilic end of the first phase, or the patterned photoresist layer is hydrophobic to attract the hydrophobic end of the first phase.
[0018] In some embodiments, the oriented self-assembly material includes a first portion having a first glass transition temperature and a second portion having a second glass transition temperature lower than the first glass transition temperature, and the first portion is adsorbed onto a patterned photoresist layer when the oriented self-assembly material separates into a first phase and a second phase.
[0019] In some embodiments, the oriented self-assembled layer is formed at a temperature between the first glass transition temperature and the second glass transition temperature.
[0020] In some embodiments, the oriented self-assembling material is a copolymer, and the copolymer is vertically arranged on the top surface of the patterned photoresist layer.
[0021] In some embodiments, the method further includes forming a hard mask layer on the target layer and forming a photoresist layer on the hard mask layer before patterning the photoresist layer. Attached Figure Description
[0022] The invention can be more fully understood by reading the following detailed description of the embodiments and referring to the accompanying drawings.
[0023] Figure 1 and Figure 2 This is a flowchart of a method for forming a patterned structure according to some embodiments of the present invention.
[0024] Figures 3 to 8 This is a cross-sectional view of a structure in multiple stages of forming a patterned structure according to some embodiments of the present invention. Detailed Implementation
[0025] To make the description of the present invention more detailed and complete, various aspects of the embodiments are described below in an illustrative manner, but this does not limit the embodiments of the present invention to only one form. Embodiments of the present invention may be combined with or substituted for each other where advantageous, and other embodiments may be added without further explanation.
[0026] Furthermore, in this invention, spatial relative terms, such as below and above, may be used to describe the relationship between one element (or feature) and another element (or feature) in the figures. In addition to the directions depicted in the figures, spatial relative terms are intended to cover different orientations of the device during use or operation. For example, the device may be oriented in other ways (e.g., rotated 90 degrees) and can be interpreted accordingly using spatial relative terms. In this invention, unless otherwise stated, the same element symbols in different figures refer to the same or similar elements formed from the same or similar materials by the same or similar methods.
[0027] The terms “about,” “approximately,” “approximately,” “substantially,” and “truly” used in this invention include, as understood by those skilled in the art, the values (or characteristics) and deviations thereof. For example, taking into account errors in values (or characteristics), these terms may indicate values within one or more standard deviations (e.g., values within ±30%, ±20%, ±15%, ±10%, or ±5%), or they may indicate deviations included in practical operation of the characteristic (e.g., “truly parallel” may indicate that practical operation is close to parallel, rather than ideally perfect parallel). Furthermore, an acceptable range of deviation may be selected based on the nature or other properties of the measurement, rather than applying only one range of deviation to all values (or characteristics).
[0028] This invention provides a method 10 for forming a patterned structure and a method 20 for forming a patterned structure, such as... Figure 1 and Figure 2 As shown. While reading Figure 1 and Figure 2 Further details regarding the present invention may be found elsewhere. Figures 3 to 8 Methods 10 and 20 include the following operations. In operation 11 of method 10 and operation 21 of method 20, a photoresist layer 103 is patterned on the target layer 101 to form a first opening 104 in the patterned photoresist layer 105. In operation 12 of method 10 and operation 22 of method 20, a directed self-assembly layer 106 is formed on the patterned photoresist layer 105 and in the first opening 104. In operation 12 of method 10, the directed self-assembly material in the directed self-assembly layer 106 is attracted by the polarity of the patterned photoresist layer 105 and separated into a first phase 106A on the patterned photoresist layer 105 and a second phase 106B in the first opening 104. However, in operation 22 of method 20, the oriented self-assembled material in the oriented self-assembled layer 106 is attracted by the water affinity of the patterned photoresist layer 105 and separated into a first phase 106A and a second phase 106B, wherein the first phase 106A covers the top surface of the patterned photoresist layer 105 and the side surface of the first opening 104, and the first phase 106A surrounds the second phase 106B. In operation 13 of method 10 and operation 23 of method 20, the second phase 106B is removed to form a second opening 107 through the first phase 106A of the oriented self-assembled layer 106. In operation 14 of method 10 and operation 24 of method 20, the target layer 101 is etched through the second opening 107.
[0029] This invention uses a combination of a patterned photoresist layer 105 and a first phase 106A of an oriented self-assembled layer 106 to pattern the target layer 101. Therefore, compared to patterning the target layer 101 using only the patterned photoresist layer 105, the photoresist layer 103 of this invention can be thinner, thus preventing light standing waves from remaining in the photoresist layer 103 and altering the desired pattern of the first opening 104 formed when the patterned photoresist layer 103 is changed in operations 11 and 21. Once the pattern of the first opening 104 meets expectations, such as not increasing roughness, not causing footing or undercutting, the second opening 107 formed in operations 13 and 23 by removing the second phase 106B of the oriented self-assembled layer 106 in the first opening 104 can also have the same high quality as the first opening 104. In addition to the high quality of the second opening 107, the thickness of the mask used to etch the target layer 101 in operations 14 and 24 includes contributions from the first phase 106A of the patterned photoresist layer 105 and the oriented self-assembled layer 106. Therefore, the mask can be thick enough to form a pattern with a larger aspect ratio in the target layer 101. Overall, the pattern formed in the target layer 101 has high quality, for example, it can reduce roughness to improve line edge roughness (LER) and / or line width roughness (LWR), reduce bases or undercuts, etc., and the pattern in the target layer 101 can have a larger aspect ratio. Next, the methods 10 and 20 of the present invention will be described in detail through the following embodiments.
[0030] Reference Figure 3Prior to performing the patterned photoresist layer 103 in operations 11 and 21, in some embodiments, methods 10 and 20 may further include forming a hard mask layer 102 on the target layer 101 and forming the photoresist layer 103 on the hard mask layer 102. The target layer 101 may be any layer to be etched in subsequent operations. The photoresist layer 103 is patterned to form a patterned photoresist layer 105 that can be used in subsequent operations, such that the patterned photoresist layer 105 can thus serve as a mask for etching the target layer 101. In subsequent operations, the hard mask layer 102 may also serve as a mask similar to the patterned photoresist layer 105 for etching the target layer 101, wherein, during etching of the target layer 101, the pattern formed in the patterned photoresist layer 105 (e.g., the second opening 107) is transferred to the hard mask layer 102. Compared to embodiments excluding the hard mask layer 102, the hard mask layer 102 has greater etch resistance than the photoresist layer 103, thus making it easier to maintain consistent pattern dimensions when transferring the pattern to the target layer 101. In some embodiments, the hard mask layer 102 comprises any suitable hard mask material, such as amorphous carbon, silicon nitride, or combinations thereof. In some embodiments, the hard mask layer 102 is a neutral layer, with no preference for the arrangement of the oriented self-assembly materials in the oriented self-assembly layer 106. In some embodiments, the hard mask layer 102 and the photoresist layer 103 are formed by any suitable method, such as chemical vapor deposition or physical vapor deposition.
[0031] Reference Figure 4In operations 11 and 21, a photoresist layer 103 is patterned on the target layer 101 using any suitable photolithography method to form a first opening 104 in the patterned photoresist layer 105. Since the patterned photoresist layer 105 will work together with the first phase 106A of the oriented self-assembled layer 106 as a mask to etch the target layer 101 in subsequent operations, the thickness 103T of the photoresist layer 103 can be very thin. In some embodiments, the thickness 103T of the photoresist layer 103 is preferably 80 nm to 120 nm, for example, 80 nm, 90 nm, 100 nm, 110 nm, or 120 nm. When the thickness 103T is too large, as mentioned above, the quality of the first opening 104 may degrade, and when the thickness 103T is too small, the mask used for etching the target layer 101 in subsequent operations may not be suitable for forming a pattern with a larger aspect ratio in the target layer 101. In some embodiments, the thickness 105T of the patterned photoresist layer 105 is preferably 80 nm to 120 nm, such as 80 nm, 90 nm, 100 nm, 110 nm, or 120 nm. In some embodiments, the thickness 103T of the photoresist layer 103 and the thickness 105T of the patterned photoresist layer 105 are substantially the same. In some embodiments, the first opening 104 extends through the patterned photoresist layer 105 from the upper surface of the patterned photoresist layer 105 to the lower surface of the patterned photoresist layer 105. In some embodiments, the first opening 104 exposes a layer beneath the patterned photoresist layer 105 (e.g., exposes the target layer 101 or the hard mask layer 102).
[0032] In some embodiments, the photoresist layer 103 (or patterned photoresist layer 105) comprises any suitable photoresist material, such as polymethyl methacrylate, epoxy polymers, etc. In some embodiments, the material of the photoresist layer 103 (or patterned photoresist layer 105) is polar, such that when the oriented self-assembled layer 106 is formed on the patterned photoresist layer 105 in a subsequent operation, the patterned photoresist layer 105 can attract the polar ends of the first phase 106A in the oriented self-assembled layer 106. In some embodiments, the material of the photoresist layer 103 (or patterned photoresist layer 105) is nonpolar, such that when the oriented self-assembled layer 106 is formed on the patterned photoresist layer 105 in a subsequent operation, the patterned photoresist layer 105 can attract the nonpolar ends of the first phase 106A in the oriented self-assembled layer 106. In some embodiments, the photoresist layer 103 (or patterned photoresist layer 105) is made of a hydrophilic material, such that when the oriented self-assembled layer 106 is formed on the patterned photoresist layer 105 in a subsequent operation, the patterned photoresist layer 105 can attract the hydrophilic ends of the first phase 106A in the oriented self-assembled layer 106. In some embodiments, the photoresist layer 103 (or patterned photoresist layer 105) is made of a hydrophobic material, such that when the oriented self-assembled layer 106 is formed on the patterned photoresist layer 105 in a subsequent operation, the patterned photoresist layer 105 can attract the hydrophobic ends of the first phase 106A in the oriented self-assembled layer 106.
[0033] Reference Figure 5 and Figure 6In operations 12 and 22, a oriented self-assembled layer 106 is formed on the patterned photoresist layer 105 and in the first opening 104 by any suitable deposition method, such as chemical vapor deposition or physical vapor deposition. The oriented self-assembled material in the oriented self-assembled layer 106 can self-assemble into different phases (e.g., self-assemble into a first phase 106A and a second phase 106B) depending on the environment in which the oriented self-assembled layer 106 is located. For example, the patterned photoresist layer 105 and the first opening 104 can provide different environments for the oriented self-assembled layer 106 (e.g., provide different surface shapes, different surface properties, etc.), such that the oriented self-assembled material on the patterned photoresist layer 105 forms the first phase 106A, and the oriented self-assembled material on the first opening 104 forms the second phase 106B. By reassembling the oriented self-assembled material of the oriented self-assembled layer 106 into a first phase 106A and a second phase 106B according to the positions of the patterned photoresist layer 105 and the first opening 104, the first phase 106A can be selectively retained on the patterned photoresist layer 105 to increase its total thickness as a mask in subsequent operations, and the second phase 106B can be selectively removed to form a second opening 107 for etching the target layer 101 in subsequent operations. For example, in some embodiments, in operations 12 and 22, the total thickness T1 of the portion of the patterned photoresist layer 105 and the oriented self-assembled layer 106 on the patterned photoresist layer 105 is preferably 120 nm to 300 nm, such as 120 nm, 150 nm, 200 nm, 225 nm, 250 nm, 275 nm, or 300 nm. This ensures that the mask used for etching the target layer 101 in subsequent operations is not too thin to form a pattern with a larger aspect ratio in the target layer 101, and is not too thick to cause unnecessary waste and lack of additional benefits. In some embodiments, in operations 12 and 22, the thickness T2 of the portion of the oriented self-assembled layer 106 on the patterned photoresist layer 105 is preferably 10 nm to 180 nm, such as 10 nm, 25 nm, 50 nm, 75 nm, 100 nm, 125 nm, 150 nm, or 180 nm. In some embodiments, the first phase 106A further includes a portion extending to cover the sidewalls of the patterned photoresist layer 105. In some embodiments, the first phase 106A covers the sidewalls of the first opening 104. In some embodiments, the first phase 106A surrounds the second phase 106B, and the second phase 106B is separated from the patterned photoresist layer 105. In some embodiments, the oriented self-assembled layer 106 contacts the patterned photoresist layer 105 and contacts layers exposed through the first opening 104 (e.g., target layer 101 or hard mask layer 102).
[0034] In some embodiments, the oriented self-assembly material in the oriented self-assembly layer 106 includes a first end A and a second end B, wherein the patterned photoresist layer 105 attracts the first end A to the patterned photoresist layer 105 and repels the second end B from approaching the patterned photoresist layer 105, such that the oriented self-assembly material can be separated into a first phase 106A and a second phase 106B arranged in different ways on the patterned photoresist layer 105 and the first opening 104.
[0035] In some embodiments, the oriented self-assembled material in the oriented self-assembled layer 106 is attracted by the polarity of the patterned photoresist layer 105 and separated into a first phase 106A and a second phase 106B. For example, in some embodiments of operation 12, the first end A of the oriented self-assembled material is a polar end, the second end B of the oriented self-assembled material is a non-polar end, and the patterned photoresist layer 105 is polar to attract the polar end of the oriented self-assembled material in the first phase 106A. In some embodiments of operation 12, the first end A of the oriented self-assembled material is a non-polar end, the second end B of the oriented self-assembled material is a polar end, and the patterned photoresist layer 105 is non-polar to attract the non-polar end of the oriented self-assembled material in the first phase 106A. In some embodiments, the dipole moment of the polar end is greater than that of the non-polar end. In some embodiments, the difference between the dipole moment of the first end A of the oriented self-assembled material adsorbed on the patterned photoresist layer 105 and the dipole moment of the material of the patterned photoresist layer 105 is less than the difference between the dipole moment of the second end B of the oriented self-assembled material and the dipole moment of the material of the patterned photoresist layer 105. In some embodiments, the polar end includes vinylpyridine, isoprene, methyl methacrylate, ethylene oxide, tetrahydrofuran, oxetane, or combinations thereof. In some embodiments, the non-polar end includes styrene, isoprene, caprolactone, or combinations thereof.In some embodiments, the directional self-assembly material is a copolymer and includes monomers such as copolymers of styrene and vinylpyridine (e.g., poly(styrene-b-vinylpyridine)); copolymers of styrene and isoprene (e.g., poly(styrene-b-isoprene)); copolymers of styrene and methyl methacrylate (e.g., poly(styrene-b-methyl methacrylate)); copolymers of isoprene and ethylene oxide (e.g., poly(isoprene-b-ethylene oxide)); and copolymers of ethylene oxide and caprolactone (e.g., poly(ethylene oxide-b-caprolactone)). The following copolymers are included: styrene-b-caprolactone; styrene-b-tetrahydrofuran; styrene-b-isoprene-b-ethylene oxide; oxetane; styrene-b-dimethylsiloxane; and ethylene oxide. The copolymers of styrene and acetic acid (e.g., poly(styrene-b-acetic acid)); copolymers of styrene and vinyl alcohol (e.g., poly(styrene-b-vinyl alcohol)); or combinations thereof. In some embodiments, the copolymers of the oriented self-assembling materials are vertically aligned on the surface (e.g., the top surface) of the patterned photoresist layer 105.
[0036] In some embodiments, the oriented self-assembled material in the oriented self-assembled layer 106 is attracted by the hydrophilicity of the patterned photoresist layer 105 and separated into a first phase 106A and a second phase 106B. For example, in some embodiments of operation 22, the first end A of the oriented self-assembled material is a hydrophilic end, the second end B of the oriented self-assembled material is a hydrophobic end, and the patterned photoresist layer 105 is hydrophilic to attract the hydrophilic end of the oriented self-assembled material in the first phase 106A. In some embodiments of operation 22, the first end A of the oriented self-assembled material is a hydrophobic end, the second end B of the oriented self-assembled material is a hydrophilic end, and the patterned photoresist layer 105 is hydrophobic to attract the hydrophobic end of the oriented self-assembled material in the first phase 106A. In some embodiments, the water solubility of the hydrophilic end is greater than that of the hydrophobic end. In some embodiments, the difference between the water solubility of the first end A of the oriented self-assembled material adsorbed on the patterned photoresist layer 105 and the water solubility of the material of the patterned photoresist layer 105 is less than the difference between the water solubility of the second end B of the oriented self-assembled material and the water solubility of the material of the patterned photoresist layer 105. In some embodiments, the hydrophilic end includes vinylpyridine, isoprene, methyl methacrylate, ethylene oxide, tetrahydrofuran, butadiene, or combinations thereof. In some embodiments, the hydrophobic end includes styrene, isoprene, caprolactone, butadiene, (trimethylsilyl)methyl methacrylate, propylene oxide, or combinations thereof.In some embodiments, the oriented self-assembly material is a copolymer and includes monomers such as copolymers of styrene and vinylpyridine (e.g., poly(styrene-b-vinylpyridine)); copolymers of styrene and isoprene (e.g., poly(styrene-b-isoprene)); copolymers of styrene and methyl methacrylate (e.g., poly(styrene-b-methyl methacrylate)); copolymers of isoprene and ethylene oxide (e.g., poly(isoprene-b-ethylene oxide)); and copolymers of ethylene oxide and caprolactone (e.g., poly(ethylene oxide-b-... Copolymers including styrene and tetrahydrofuran (e.g., poly(styrene-b-tetrahydrofuran)); copolymers including styrene, isoprene, and ethylene oxide (e.g., poly(styrene-b-isoprene-b-ethylene oxide)); copolymers including styrene and butadiene (e.g., poly(styrene-b-butadiene)); copolymers including butadiene and ethylene oxide (e.g., poly(butadiene-b-ethylene oxide)). The copolymers of methyl methacrylate and (trimethylsilyl)methyl methacrylate (e.g., poly(methyl methacrylate-b-(trimethylsilyl)methyl methacrylate)) are included; copolymers of ethylene oxide and propylene oxide (e.g., poly(ethylene oxide-b-propylene oxide)) are included; copolymers of styrene and dimethylsiloxane (e.g., poly(styrene-b-dimethylsiloxane)) are included; copolymers of styrene and ethylene oxide (e.g., poly(styrene-b-ethylene oxide)) are included; copolymers of styrene and acetic acid (e.g., poly(styrene-b-acetic acid)) are included; copolymers of styrene and vinyl alcohol (e.g., poly(styrene-b-vinyl alcohol)) are included; or combinations thereof. In some embodiments, the copolymers of the oriented self-assembly material are vertically aligned on the surface (e.g., the top surface) of the patterned photoresist layer 105.
[0037] In some embodiments, the oriented self-assembly material includes a first portion having a first glass transition temperature (e.g., a monomer in the copolymer of the oriented self-assembly material) and a second portion having a second glass transition temperature lower than the first glass transition temperature (e.g., another monomer in the copolymer of the oriented self-assembly material). When the oriented self-assembly material separates into a first phase 106A and a second phase 106B, the first portion is a first end A adsorbed on the patterned photoresist layer 105, and the second portion is a second end B. In some embodiments, the oriented self-assembly layer 106 is formed at a temperature between the first and second glass transition temperatures, such that the second phase 106B is softer than the first phase 106A, facilitating removal of the second phase 106B in subsequent operations. In some embodiments, the first glass transition temperature is between 120°C and 150°C, for example, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, or 150°C. In some embodiments, the second glass transition temperature is 85°C to 115°C, for example 85°C, 90°C, 95°C, 100°C, 105°C, 110°C or 115°C.
[0038] Reference Figure 7 In operations 13 and 23, the second phase 106B of the oriented self-assembled layer 106 is removed by any suitable etching method, such as dry etching or wet etching, to form the second opening 107 in the patterned photoresist layer 105 and the first phase 106A of the oriented self-assembled layer 106. In subsequent operations, the patterned photoresist layer 105 and the first phase 106A of the oriented self-assembled layer 106 will be used as a mask to etch the target layer 101, and the second opening 107 defines the location of the pattern formed in the target layer 101.
[0039] Reference Figure 8 In operations 14 and 24, the target layer 101 is etched through the second opening 107 by any suitable etching method, such as dry etching or wet etching. In embodiments that include a hard mask layer 102, the hard mask layer 102 is etched through the second opening 107 before etching the target layer 101.
[0040] The method of this invention uses a combination of photoresist material and oriented self-assembly material to pattern a target layer. Therefore, when patterning the photoresist material layer, the photoresist material layer can be very thin to prevent standing waves of light from remaining in the photoresist material layer and thus affecting the pattern formed in the photoresist material layer. Therefore, the pattern in the photoresist material layer can be formed and transferred to the oriented self-assembly material layer as expected. Furthermore, when the target layer is etched using the patterned photoresist material layer and the oriented self-assembly material, the pattern formed in the target layer can also meet expectations, such as having higher resolution, a larger aspect ratio, reduced roughness to improve line edge roughness (LER) and / or line width roughness (LWR), and reduced foot or undercut, etc.
[0041] This invention has been described in considerable detail through some embodiments, but other embodiments may also be feasible. Therefore, the description of the embodiments is not intended to limit the scope and spirit of the appended claims. Those skilled in the art will be able to make modifications and alterations to this invention without departing from its scope and spirit. Such modifications and alterations are included in this invention when they fall within the scope and spirit of the appended claims.
[0042] [Symbol Explanation]
[0043] 10: Method
[0044] 11: Operation
[0045] 12: Operation
[0046] 13: Operation
[0047] 14: Operation
[0048] 20: Method
[0049] 21: Operation
[0050] 22: Operation
[0051] 23: Operation
[0052] 24: Operation
[0053] 101: Target Layer
[0054] 102: Hard mask layer
[0055] 103: Photoresist layer
[0056] 103T: Thickness
[0057] 104: First Opening
[0058] 105: Patterned photoresist layer
[0059] 105T: Thickness
[0060] 106: Directed Self-Assembly Layer
[0061] 106A: First Phase
[0062] 106B: Second Phase
[0063] 107: Second opening
[0064] A: First end
[0065] B: Second end
[0066] T1: Total thickness
[0067] T2: Thickness.
Claims
1. A method for forming a patterned structure, characterized in that, include: A photoresist layer is patterned on the target layer to form a first opening in the patterned photoresist layer; An oriented self-assembly layer is formed on the patterned photoresist layer and in the first opening, wherein the oriented self-assembly material in the oriented self-assembly layer is separated into a first phase on the patterned photoresist layer and a second phase in the first opening by being attracted by the polarity of the patterned photoresist layer. Remove the second phase to form a second opening through the oriented self-assembled layer; as well as The target layer is etched through the second opening.
2. The method according to claim 1, wherein the thickness of the photoresist layer is 80 nm to 120 nm.
3. The method according to claim 1, wherein when the oriented self-assembled layer is formed on the patterned photoresist layer, the total thickness of the patterned photoresist layer and a portion of the oriented self-assembled layer on the patterned photoresist layer is 120 nm to 300 nm.
4. The method of claim 1, wherein when forming the oriented self-assembled layer on the patterned photoresist layer, the thickness of a portion of the oriented self-assembled layer on the patterned photoresist layer is 10 nm to 180 nm.
5. The method of claim 1, wherein the patterned photoresist layer is polar to attract the polar end of the first phase, or the patterned photoresist layer is non-polar to attract the non-polar end of the first phase.
6. The method of claim 1, wherein the oriented self-assembled material comprises a first portion having a first glass transition temperature and a second portion having a second glass transition temperature lower than the first glass transition temperature, and the first portion is adsorbed onto the patterned photoresist layer when the oriented self-assembled material separates into the first phase and the second phase.
7. The method of claim 6, wherein the oriented self-assembled layer is formed at a temperature between the first glass transition temperature and the second glass transition temperature.
8. The method of claim 1, wherein the oriented self-assembly material is a copolymer, and the copolymer is arranged vertically on the surface of the patterned photoresist layer.
9. The method of claim 1, wherein the first phase further includes a portion extending to a side surface covering the patterned photoresist layer.
10. The method according to claim 1, wherein, It also includes forming a hard mask layer on the target layer and forming the photoresist layer on the hard mask layer before patterning the photoresist layer.
11. A method for forming a patterned structure, characterized in that, include: A photoresist layer is patterned on the target layer to form a first opening in the patterned photoresist layer; An oriented self-assembly layer is formed on the patterned photoresist layer and in the first opening, wherein the oriented self-assembly material in the oriented self-assembly layer is separated into a first phase and a second phase by being attracted by the hydrophilicity of the patterned photoresist layer, the first phase covering the top surface of the patterned photoresist layer and the side surface of the first opening, and the first phase surrounding the second phase; Remove the second phase to form a second opening through the oriented self-assembled layer; as well as The target layer is etched through the second opening.
12. The method of claim 11, wherein the thickness of the photoresist layer is 80 nm to 120 nm.
13. The method of claim 11, wherein when forming the oriented self-assembled layer on the patterned photoresist layer, the total thickness of the patterned photoresist layer and a portion of the oriented self-assembled layer on the patterned photoresist layer is 120 nm to 300 nm.
14. The method of claim 11, wherein when forming the oriented self-assembled layer on the patterned photoresist layer, the thickness of a portion of the oriented self-assembled layer on the patterned photoresist layer is from 10 nm to 180 nm.
15. The method of claim 11, wherein the patterned photoresist layer is hydrophilic to attract the hydrophilic end of the first phase, or the patterned photoresist layer is hydrophobic to attract the hydrophobic end of the first phase.
16. The method of claim 11, wherein the oriented self-assembled material comprises a first portion having a first glass transition temperature and a second portion having a second glass transition temperature lower than the first glass transition temperature, and the first portion is adsorbed onto the patterned photoresist layer when the oriented self-assembled material separates into the first phase and the second phase.
17. The method of claim 16, wherein the oriented self-assembled layer is formed at a temperature between the first glass transition temperature and the second glass transition temperature.
18. The method of claim 11, wherein the oriented self-assembly material is a copolymer, and the copolymer is vertically arranged on the top surface of the patterned photoresist layer.
19. The method according to claim 11, wherein, It also includes forming a hard mask layer on the target layer and forming the photoresist layer on the hard mask layer before patterning the photoresist layer.