Pattern manufacturing method
A simplified pattern manufacturing method using an indium-containing oxide hard mask allows for efficient production of patterns with high aspect ratios and precise contact holes by combining wet and dry etching techniques, addressing the complexity of existing processes.
Patent Information
- Application Number
- JP2024062479
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-04-09
- Publication Date
- 2025-10-22
AI Technical Summary
The existing patterning process for manufacturing patterns with high aspect ratios is complicated and inefficient.
A pattern manufacturing method involving the formation of a hard mask made of indium-containing oxide without tin, which is amorphous and can be easily wet-etched using a weak acid like oxalic acid, and used to create a pattern with high selectivity during dry etching, followed by peeling off the mask after etching.
Enables the production of patterns with high aspect ratios efficiently by simplifying the process and ensuring precise, small-diameter contact holes without dimensional shifts, suitable for high-definition displays.
Smart Images
Figure 2025159752000001_ABST
Abstract
Description
[Technical Field]
[0001] The present disclosure relates to a pattern manufacturing method. [Background technology]
[0002] Patent Document 1 discloses a patterning process for etching a film stack. In the patterning process, a bottom antireflective coating layer is formed on the film stack, a hard mask layer is formed on the bottom antireflective coating layer, and a photoresist layer is formed on the hard mask layer. The hard mask layer is made of a metal-containing material. Then, a photoresist layer is patterned, the hard mask layer is patterned so that openings in the patterned photoresist layer are transferred to the hard mask layer, and the bottom antireflective coating layer is patterned so that openings in the patterned hard mask layer are transferred to the bottom antireflective coating layer. Finally, the film stack is etched. In the patterning process, a patterned bottom antireflective coating layer is formed on the film stack, a patterned hard mask layer is formed on the patterned bottom antireflective coating layer, and a patterned photoresist layer is formed on the patterned hard mask layer. (Paragraphs 0014, 0033, 0035, 0040, 0049, 0058, and 0064) [Prior art documents] [Patent documents]
[0003] [Patent Document 1] Special Publication No. 2023-527694 Summary of the Invention [Problem to be solved by the invention]
[0004] The patterning process disclosed in US Pat. No. 6,213,999 is significantly more complicated.
[0005] In view of this problem, an object of one aspect of the present disclosure is to provide a simple pattern manufacturing method that can manufacture a pattern having a high aspect ratio, for example. [Means for solving the problem]
[0006] A pattern manufacturing method according to one embodiment of the present disclosure includes: a) forming a film; b) forming a hard mask made of an oxide containing indium but not containing tin on the film to form a first portion covered by the hard mask and a second portion not covered by the hard mask on the film; c) dry-etching the second portion; and d) peeling off the hard mask after step c). [Brief explanation of the drawings]
[0007] [Figure 1A] 1 is a cross-sectional view schematically illustrating an intermediate product of a pattern manufactured by the pattern manufacturing method of the first embodiment. [Figure 1B] FIG. 2 is a top view schematically illustrating an intermediate product of a pattern manufactured by the pattern manufacturing method of the first embodiment. [Figure 2A] 1 is a cross-sectional view schematically illustrating an intermediate product of a pattern manufactured by the pattern manufacturing method of the first embodiment. [Figure 2B] FIG. 2 is a top view schematically illustrating an intermediate product of a pattern manufactured by the pattern manufacturing method of the first embodiment. [Figure 3A] 1 is a cross-sectional view schematically illustrating an intermediate product of a pattern manufactured by the pattern manufacturing method of the first embodiment. [Figure 3B] FIG. 2 is a top view schematically illustrating an intermediate product of a pattern manufactured by the pattern manufacturing method of the first embodiment. [Figure 4A] 1 is a cross-sectional view schematically illustrating an intermediate product of a pattern manufactured by the pattern manufacturing method of the first embodiment. [Figure 4B] FIG. 2 is a top view schematically illustrating an intermediate product of a pattern manufactured by the pattern manufacturing method of the first embodiment. [Figure 5A] 1 is a cross-sectional view schematically illustrating an intermediate product of a pattern manufactured by the pattern manufacturing method of the first embodiment. [Figure 5B] FIG. 2 is a top view schematically illustrating an intermediate product of a pattern manufactured by the pattern manufacturing method of the first embodiment. [Figure 6A] 1 is a cross-sectional view schematically illustrating an intermediate product of a pattern manufactured by the pattern manufacturing method of the first embodiment. [Figure 6B] FIG. 2 is a top view schematically illustrating an intermediate product of a pattern manufactured by the pattern manufacturing method of the first embodiment. [Figure 7A] 1 is a cross-sectional view schematically illustrating a pattern manufactured by a pattern manufacturing method according to a first embodiment. [Figure 7B] FIG. 1 is a top view schematically illustrating a pattern manufactured by the pattern manufacturing method of the first embodiment. [Figure 8] 1 is a flowchart showing the flow of a pattern manufacturing method according to a first embodiment. [Figure 9] 10 is a flowchart showing the flow of a pattern manufacturing method according to a modified example of the first embodiment. [Figure 10] FIG. 2 is a cross-sectional view schematically illustrating a mask made of an insulating film and a positive resist. [Figure 11] FIG. 2 is a cross-sectional view schematically illustrating a mask made of an insulating film and a negative resist. DETAILED DESCRIPTION OF THE INVENTION
[0008] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the same or equivalent elements are designated by the same reference numerals, and redundant description will be omitted.
[0009] 1. First embodiment 1.1 Pattern manufacturing method 1A, 2A, 3A, 4A, 5A, and 6A are cross-sectional views schematically illustrating intermediate products of a pattern manufactured by the pattern manufacturing method of the first embodiment. FIG. 7A is a cross-sectional view schematically illustrating a pattern manufactured by the pattern manufacturing method of the first embodiment. FIGS. 1B, 2B, 3B, 4B, 5B, and 6B are top views schematically illustrating intermediate products of a pattern manufactured by the pattern manufacturing method of the first embodiment. FIG. 7B is a top view schematically illustrating a pattern manufactured by the pattern manufacturing method of the first embodiment. FIG. 8 is a flowchart showing the flow of the pattern manufacturing method of the first embodiment.
[0010] In the pattern manufacturing method of the first embodiment, steps S101 to S107 shown in FIG. 8 are executed.
[0011] In step S101, as shown in FIGS. 1A and 1B, a film 101 is formed on a substrate. In the first embodiment, the film 101 is an insulating film made of an insulator. The insulator is a resin. The insulator may be a material other than a resin. For example, the insulator may be silicon nitride (SiN x ), silicon oxide (SiO x ) etc.
[0012] In the subsequent step S102, as shown in FIGS. 2A and 2B, an oxide film 102 is formed on the film 101. The formed oxide film 102 is made of an oxide. The oxide contains indium but does not contain tin. The oxide is preferably indium zinc oxide (IZO) or indium gallium zinc oxide (IGZO). The oxide film 102 is in direct contact with the film 101.
[0013] An oxide film made of an oxide containing tin, such as indium tin oxide (ITO), crystallizes and becomes non-amorphous when exposed to high temperatures of 200°C or higher. Therefore, the oxide film does not dissolve in a weak acid, such as oxalic acid, after being exposed to high temperatures of 200°C or higher. Therefore, the oxide film cannot be wet-etched by an acid etching process (SLA) using a weak acid, such as oxalic acid, after being exposed to high temperatures of 200°C or higher.
[0014] In contrast, an oxide film 102 made of an oxide containing indium but not tin, such as IZO or IGZO, does not crystallize and remains amorphous even when exposed to high temperatures of 200° C. or higher. Therefore, the oxide film 102 is easily dissolved in a weak acid such as oxalic acid, even after being exposed to high temperatures of 200° C. or higher. Therefore, the oxide film 102 can be easily wet-etched by SLA using a weak acid such as oxalic acid, even after being exposed to high temperatures of 200° C. or higher.
[0015] In addition, the oxide film 102 made of an oxide containing indium but not tin, such as IZO or IGZO, has high dry etching resistance and is hardly etched by dry etching. Therefore, a hard mask formed by patterning the oxide film 102 has a high selectivity when dry etching is performed.
[0016] 3A and 3B, a resist pattern 103 is formed on the oxide film 102. The formed resist pattern 103 covers a part of the upper surface of the oxide film 102. As a result, a protected portion 102a protected by the resist pattern 103 and an unprotected portion 102b not protected by the resist pattern 103 are formed in the oxide film 102. In forming the resist pattern 103, for example, a resist film made of a general positive resist is formed on the entire upper surface of the oxide film 102, and the formed resist film is patterned by photolithography.
[0017] In the next step S104, as shown in Figures 4A and 4B, the unprotected portions 102b are wet-etched by SLA using a weak acid such as oxalic acid. At this time, the protected portions 102a are left unetched. As a result, the oxide film 102 is patterned to obtain a hard mask 104 made of the protected portions 102a. The unprotected portions 102b may also be etched by a method other than SLA using a weak acid.
[0018] Through steps S103 and S104, a hard mask 104 made of amorphous oxide containing indium but not tin, such as IZO or IGZO, is formed on the film 101. The formed hard mask 104 is in direct contact with the upper surface of the film 101. The hard mask 104 covers part of the upper surface of the film 101. As a result, a first portion 101a protected by the hard mask 104 and a second portion 101b not protected by the hard mask 104 are formed in the film 101.
[0019] The hard mask 104 is hardly etched by dry etching, so it is sufficient for the hard mask 104 to have a slight thickness, for example, a thickness of 100 nm or less.
[0020] In the following step S105, the resist pattern 103 is stripped off as shown in FIGS. 5A and 5B.
[0021] In the subsequent step S106, as shown in FIGS. 6A and 6B, the second portion 101b is dry-etched. As described above, the hard mask 104 has a high selectivity when dry-etching is performed. As a result, only the second portion 101b is selectively dry-etched, and the first portion 101a remains unetched. As a result, the film 101 is patterned to form a pattern 105 made of the first portion 101a. In dry-etching the second portion 101b, anisotropic dry etching under low pressure is preferably performed.
[0022] During dry etching of the second portion 101b, molecules constituting the etching gas collide with the hard mask 104, causing the temperature of the hard mask 104 to rise to a high temperature of 200°C or higher. However, the hard mask 104 can maintain an amorphous state even when the temperature of the hard mask 104 reaches a high temperature of 200°C or higher. Therefore, even after the second portion 101b has been dry-etched, the hard mask 104 is easily dissolved in a weak acid such as oxalic acid, and can be easily wet-etched by SLA using a weak acid such as oxalic acid.
[0023] 7A and 7B, the hard mask 104 is stripped, leaving the pattern 105. In stripping the hard mask 104, the hard mask 104 is wet-etched by SLA using a weak acid such as oxalic acid.
[0024] The film 101 formed in step S101 is not particularly limited, but may be, for example, an interlayer insulating film provided in a high-definition liquid crystal display (LCD) such as a head-mounted display (HMD) using a color filter on array (COA). When the film 101 formed in step S101 is an interlayer insulating film, a pattern 105 can be formed in which a through-hole 105h having a planar shape similar to the planar shape of the through-hole 103h shown in Figures 3A and 3B is formed. The through-hole formed in the pattern 105 becomes, for example, a contact hole connecting a thin film transistor and a pixel electrode.
[0025] 1.2 Variations FIG. 9 is a flowchart showing the flow of a pattern manufacturing method according to a modified example of the first embodiment.
[0026] In the first embodiment, as shown in FIG. 8, after the hard mask 104 is formed in S104 and before the second portion 101b is dry-etched in step S106, the resist pattern 103 is stripped in step S105.
[0027] In contrast, in the modified example of the first embodiment, as shown in FIG. 9, after the second portion 101b is dry-etched in step S106 and before the hard mask 104 is stripped in step S107, the resist pattern 103 is stripped in step S105.
[0028] 1.3 Comparison of masks made of positive resist, masks made of negative resist, and hard masks made of oxides containing indium but not tin The manufacture of high-resolution, narrow-frame flat panel displays (FPDs) often requires the formation of small-diameter contact holes that extend straight through the insulating film thickness direction in a thick insulating film. However, when contact holes are formed by wet etching, even with an ideal mask, the etching proceeds in the direction of the insulating film surface, resulting in a contact hole diameter that is larger than the diameter of the mask pattern. This necessitates the formation of contact holes by highly anisotropic dry etching. Therefore, the mask must have high dry-etching resistance. In addition, the mask must be easily peelable. Furthermore, the mask must have a shape suitable for forming small-diameter contact holes that extend straight through the insulating film thickness direction.
[0029] FIG. 10 is a cross-sectional view that schematically illustrates a mask made of an insulating film and a positive resist.
[0030] The mask 801 made of a positive resist shown in FIG. 10 has a relatively high dry etching resistance.
[0031] The mask 801 made of positive resist is formed by exposing the film to light to form exposed and unexposed portions, and then removing the exposed portions by development. The light that exposes the film is less likely to reach the film as it travels downward. For this reason, the mask 801 made of positive resist often has a forward tapered cross-sectional shape that narrows as it travels upward. Therefore, when the insulating film 802 is dry-etched using the mask 801 made of positive resist, the side surfaces of the mask 801 are dry-etched along with the insulating film 802, narrowing the width of the mask 801. This causes a dimensional shift, and the diameter of the holes formed in the insulating film 802 becomes larger.
[0032] FIG. 11 is a cross-sectional view that schematically illustrates a mask made of an insulating film and a negative resist.
[0033] The negative resist mask 901 shown in FIG. 11 is formed by exposing the film to light to form exposed and unexposed portions, and then developing to remove the unexposed portions. The light that exposes the film is less likely to reach the film as it travels downward. Therefore, the negative resist mask 901 often has a reverse tapered cross-sectional shape that becomes thicker as it travels upward. Therefore, when the insulating film 902 is dry-etched using the negative resist mask 901, the side surfaces of the mask 901 are not dry-etched, and the width of the mask 901 does not become narrower. Therefore, no dimensional shift occurs, and the diameter of the holes formed in the insulating film 902 is roughly the same as the diameter of the mask 901.
[0034] Novolac-based negative resists, which are primarily used in the manufacture of FPDs and other devices, can generally be removed by wet stripping using a stripping solution. However, dry etching alters the surface, making it impossible to remove the resist by wet stripping alone. For this reason, when novolac-based negative resists are used in dry etching, the surface area is generally removed by ashing using ozone, and the remaining area is then removed by wet stripping using a stripping solution. However, when high-definition semiconductors are manufactured, the negative resist is removed by ashing using ozone without wet stripping.
[0035] Furthermore, a mask made of a novolac-based negative resist does not have sufficiently high dry etching resistance.
[0036] Acrylic negative resists have relatively high dry etching resistance.
[0037] However, acrylic negative resists are expensive and have low photosensitivity. Therefore, masks made of acrylic negative resists have problems such as requiring a long exposure time. The development of acrylic negative resists suitable for masks has not progressed.
[0038] In contrast, the hard mask 104 made of an oxide containing indium but not tin has high dry etching resistance, as described above. Furthermore, as described above, the hard mask 104 can be easily stripped by SLA using a weak acid such as oxalic acid. Furthermore, a slight thickness is sufficient for the hard mask 104, and the through holes 104h formed in the hard mask 104 extend straight in the thickness direction of the hard mask 104 and do not have a tapered shape. Therefore, the hard mask 104 has a shape suitable for forming small-diameter contact holes that extend straight in the thickness direction of the insulating film.
[0039] The present disclosure is not limited to the above-described embodiments, and may be replaced with a configuration that is substantially the same as the configuration shown in the above-described embodiments, a configuration that has the same effect, or a configuration that can achieve the same purpose. [Explanation of symbols]
[0040] 101 Membrane 101a First Part 101b Second Part 102 Oxide film 102a Protected part 102b Unprotected part 103 Resist Pattern 104 Hard Mask 105 patterns
Claims
1. a) forming a film; b) forming a hard mask on the film, the hard mask being made of an oxide containing indium and not containing tin, to form a first portion of the film covered by the hard mask and a second portion of the film not covered by the hard mask; c) dry etching the second portion; d) stripping the hard mask after step c); A pattern manufacturing method comprising:
2. The oxide is indium zinc oxide or indium gallium zinc oxide. The pattern manufacturing method according to claim 1 .
3. the hard mask is made of amorphous, Step c) maintains the hard mask in the amorphous state. The pattern manufacturing method according to claim 1 or 2.
4. The hard mask can maintain the amorphous state even when the temperature of the hard mask reaches 200° C. or higher, In step c), the temperature of the hard mask is 200° C. or higher. The pattern manufacturing method according to claim 3 .
5. the hard mask is soluble in a weak acid; Step c) comprises dissolving the hard mask in the weak acid. The pattern manufacturing method according to claim 1 or 2.
6. The hard mask has a thickness of 100 nm or less. The pattern manufacturing method according to claim 1 or 2.
7. the film is an interlayer insulating film, In step c), a contact hole is formed in the interlayer insulating film. The pattern manufacturing method according to claim 1 or 2.
8. Step a) is a-1) forming an oxide film made of the oxide on the film; a-2) forming a resist pattern on the oxide film to form a protected portion covered with the resist pattern and an unprotected portion not covered with the resist pattern on the oxide film; a-3) etching the unprotected portion with a weak acid to obtain the hard mask; Equipped with The pattern manufacturing method includes: e) a step of stripping the resist pattern after step b) and before step c) or after step c) and before step d) Equipped with The pattern manufacturing method according to claim 1 or 2.
Citation Information
Patent Citations
Selective deposition of carbon onto photoresist layers in lithography applications
JP2023527694A