Method of forming a semiconductor device

Abstract

A method of forming a semiconductor device includes forming first sacrificial patterns on an underlying structure; forming first remaining mask layers having a "U" shape between the first sacrificial patterns such that the first remaining mask layers are in contact with the first sacrificial patterns; forming first remaining mask patterns by patterning the first remaining mask layers, each of the first remaining mask patterns including a horizontal portion parallel to an upper surface of the underlying structure and a vertical portion perpendicular to the upper surface of the underlying structure; forming second mask patterns spaced apart from the vertical portions of the first remaining mask patterns; removing the first sacrificial patterns remaining after forming the second mask patterns; and forming first mask patterns by etching the horizontal portions of the first remaining mask patterns.

Description

[0001] Cross-reference to related applications

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2018-0138093, filed on November 12, 2018, with the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] The present invention relates to a method for forming a semiconductor device, and more specifically, to a method for forming fine patterns and a method for forming a semiconductor device using such patterns. Background Technology

[0004] As semiconductor devices become highly integrated, the size of patterns on semiconductor devices decreases. However, there are limitations in forming fine patterns using such exposure equipment due to the optical resolution limitations. Summary of the Invention

[0005] One aspect of the present invention provides a method for forming a semiconductor device in which fine patterns can be formed.

[0006] According to one aspect of the present invention, a method of forming a semiconductor device includes: forming a first sacrificial pattern on a lower structure; forming a first residual mask layer having a "U" shape between the first sacrificial patterns such that the first residual mask layer contacts the first sacrificial pattern; forming a first residual mask pattern by patterning the first residual mask layer, each of the first residual mask patterns including a horizontal portion parallel to an upper surface of the lower structure and a vertical portion perpendicular to the upper surface of the lower structure; forming a second mask pattern spaced apart from the vertical portions of the first residual mask pattern; removing the first sacrificial pattern after forming the second mask pattern; and forming the first mask pattern by etching the horizontal portions of the first residual mask pattern.

[0007] According to one aspect of the present invention, a method of forming a semiconductor device includes: forming first sacrificial patterns on a lower structure, each of the first sacrificial patterns having a first width and the first sacrificial patterns being spaced apart from each other by a first distance greater than the first width; forming first residual mask patterns between the first sacrificial patterns to contact the first sacrificial patterns, each of the first residual mask patterns including a horizontal portion parallel to an upper surface of the lower structure and a vertical portion perpendicular to the upper surface of the lower structure; forming a second mask pattern spaced apart from the vertical portions of the first residual mask patterns; removing the remaining first sacrificial patterns after forming the second mask pattern; and forming the first mask pattern by anisotropically etching the first residual mask pattern.

[0008] According to one aspect of the present invention, a method of forming a semiconductor device includes: forming a first residual mask pattern on a lower structure, each of the first residual mask patterns including a horizontal portion parallel to an upper surface of the lower structure and a vertical portion extending from a portion of the horizontal portion in a direction perpendicular to the upper surface of the lower structure; forming a second mask pattern on the lower structure after forming the first residual mask pattern; and performing anisotropic etching on the first residual mask pattern and the second mask pattern. The horizontal portion of the first residual mask pattern is etched by anisotropic etching to form the first mask pattern, and the second mask pattern is formed by a first pattern contacting the horizontal portion of the first residual mask pattern and a second pattern spaced apart from the first residual mask pattern. Attached Figure Description

[0009] The above and other aspects, features and advantages of this disclosure will become clear from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0010] Figures 1 to 16 This is a diagram illustrating an example of a method for forming a semiconductor device according to some embodiments of the concept of the present invention;

[0011] Figure 17A and Figure 17B This is a cross-sectional view illustrating an example of a method for forming a semiconductor device according to some embodiments of the concept of the present invention;

[0012] Figures 18A to 18C This is a cross-sectional view illustrating an example of a method for forming a semiconductor device according to some embodiments of the concept of the present invention;

[0013] Figures 19 to 21 These are illustrations showing examples of methods for forming semiconductor devices according to some embodiments of the present invention; and

[0014] Figures 22 to 33 This is a diagram illustrating an example of a method for forming a semiconductor device according to some embodiments of the concept of the present invention. Detailed Implementation

[0015] Hereinafter, various examples of methods for forming semiconductor devices according to embodiments of the present invention will be described with reference to the accompanying drawings. Figures 1 to 16 Examples of methods for forming semiconductor devices according to embodiments are described. Figures 1 to 16 middle, Figure 1 , Figure 3 , Figure 5 , Figure 7 , Figure 9 , Figure 11 , Figure 13 and Figure 15 This is a plan view illustrating an example of a method for forming a semiconductor device according to an embodiment. Figure 2 , Figure 4A , Figure 4B , Figure 4C , Figure 6 , Figure 8 , Figure 10A , Figure 10B , Figure 12A , Figure 12B , Figure 14 and Figure 16 It shows along Figure 1 , Figure 3 , Figure 5 , Figure 7 , Figure 9 , Figure 11 , Figure 13 and Figure 15 The sectional view of the area intercepted by line I-I' in the plan view.

[0016] Reference Figure 1 and Figure 2 A first sacrificial pattern 10 may be formed on the lower structure 5. The first sacrificial pattern 10 may be formed in a linear shape. The first sacrificial pattern 10 may be formed from a spin-coated hard mask (SOH) material. For example, the first sacrificial pattern 10 may be formed from a carbon-containing material. The steps of forming the first sacrificial pattern 10 may include: forming a sacrificial material layer on the lower structure 5, and patterning the sacrificial material layer using photolithography with an exposure apparatus. The terms first, second, third, etc., used herein are used only to distinguish or differentiate one element from another.

[0017] The first mask layer 15 may be formed conformally on the lower structure 5 having the first sacrificial pattern 10. For example, the first mask layer 15 may extend over or cover the upper and side surfaces of each of the first sacrificial patterns 10 and a portion of the lower structure 5 disposed between the first sacrificial patterns 10. As used herein, an element covering another element or surface may partially or completely cover said element or surface.

[0018] In the example, atomic layer deposition (ALD) can be used to form the first mask layer 15 from silicon oxide. In some embodiments, the material of the first mask layer 15 is not limited to silicon oxide, but can be formed from another material such as silicon oxynitride (SiON) instead of silicon oxide.

[0019] The first mask layer 15 can be formed at a temperature at which the first sacrificial pattern 10 does not deform. For example, when the first sacrificial pattern 10 is formed from an SOH material formed at a first temperature, the first mask layer 15 can be formed at a second temperature lower than the first temperature. For example, when the first sacrificial pattern 10 is formed at about 260°C, the first mask layer 15 can be formed at a temperature lower than 260°C (e.g., lower than 250°C).

[0020] The first sacrificial pattern 10 may be formed according to a first pitch Pa. Each of the first sacrificial patterns 10 may have a first width Wa. The first sacrificial patterns 10 may be spaced apart from each other by a first distance Sa. The ratio of the first width (Wa) to the first distance (Sa) may be about 3 to 7. The sum of the first width Wa and the first distance Sa may be the first pitch Pa. The first thickness ta1 of the first mask layer 15 may be about one-third of the first width Wa.

[0021] Reference Figure 3 and Figure 4A A second sacrificial pattern 20 may be formed on the first mask layer 15 to fill the space between the first sacrificial patterns 10. As used herein, the element filling the space or region may partially or completely fill the space or region. The steps of forming the second sacrificial pattern 20 may include: forming a sacrificial material layer on the first mask layer 15; and etching the sacrificial material layer until the first mask layer 15 formed on the first sacrificial patterns 10 is exposed. The second sacrificial pattern 20 may be formed of the same material as the first sacrificial pattern 10.

[0022] Reference Figure 3 and Figure 4B The portion of the first mask layer 15 located on the first sacrificial pattern 10 can be removed to expose the upper surface of the first sacrificial pattern 10. It should be understood that the elements described herein may not be completely removed. The first mask layer 15 can be formed as a first residual mask layer 15a having a "U" shape, located between the first sacrificial patterns 10 and below or under the second sacrificial pattern 20. A sacrificial capping layer 22 can be formed on the first sacrificial pattern 10 and the second sacrificial pattern 20. The sacrificial capping layer 22 can be formed of the same material as the first sacrificial pattern 10 and the second sacrificial pattern 20.

[0023] Reference Figure 3 and Figure 4C The sacrificial capping layer 22, the first sacrificial pattern 10, and the second sacrificial pattern 20 may be etched sequentially to expose the upper region of the first remaining mask layer 15a. The sacrificial capping layer 22 may be etched and removed, and the first sacrificial pattern 10 and the second sacrificial pattern 20 may be partially etched to reduce their height, thereby exposing the upper region of the first remaining mask layer 15a.

[0024] In some embodiments, after the sacrificial capping layer 22 is formed, the sacrificial capping layer 22 and the first sacrificial pattern 10 and the second sacrificial pattern 20 are etched in sequence, so that the first sacrificial pattern 10 and the second sacrificial pattern 20 can be reduced in height to have substantially the same height.

[0025] Reference Figure 5 and Figure 6The upper spacer 25 may be formed on the side surface of the upper region of the first remaining mask layer 15a. The upper spacer 25 may be formed on the first sacrificial pattern 10 and the second sacrificial pattern 20, and may extend on or cover the side surface of the upper region of the first remaining mask layer 15a.

[0026] The step of forming the upper spacer 25 may include: conformally forming a spacer material layer on the lower structure 5 having a first residual mask layer 15a and a first sacrificial pattern 10 and a second sacrificial pattern 20 with reduced height; and anisotropically etching the spacer material layer. The upper spacer 25 may be formed of a material having etch selectivity relative to the first sacrificial pattern 10, the second sacrificial pattern 20, and the first residual mask layer 15a. For example, the upper spacer 25 may be formed of polysilicon or silicon nitride. The upper spacer 25 may be formed at a temperature that does not deform the first sacrificial pattern 10, as described above for the first mask layer 15 (see...). Figure 1 and Figure 2 As in ( ).

[0027] Reference Figure 7 and Figure 8 The upper spacer 25 and the first remaining mask layer 15a can be used as etching masks to etch the first sacrificial pattern 10 and the second sacrificial pattern 20. As a result, the first sacrificial pattern 10 can be etched to form the first sacrificial spacer 10a, and the second sacrificial pattern 20 can be etched to form the second sacrificial spacer 20a.

[0028] Reference Figure 9 and Figure 10A The upper spacer 25 can be used as an etching mask to etch the first remaining mask layer 15a. As a result, the first remaining mask layer 15a with a "U" shape can be formed into a first remaining mask pattern 15b with an "L" shape.

[0029] Each of the first remaining mask patterns 15b may include a horizontal portion 15b1 parallel to the upper surface 5s of the lower structure 5 and a vertical portion 15b2 extending from a portion of the horizontal portion 15b1 in a direction perpendicular to the upper surface 5s of the lower structure 5.

[0030] The first sacrificial spacer 10a may contact the lower structure 5. The second sacrificial spacer 20a may be formed on the horizontal portion 15b1 of the first residual mask pattern 15b. The vertical portion 15b2 of the first residual mask pattern 15b may be formed between the adjacent first sacrificial spacer 10a and the second sacrificial spacer 20a.

[0031] As described above, each of the first sacrificial patterns 10 may be formed having a first width Wa. The first sacrificial patterns 10 may be spaced apart from each other by a first distance Sa. Each of the first sacrificial patterns 10 may be formed by two of the first sacrificial spacers 10a that are spaced apart from each other, and each of the second sacrificial patterns 20 may be formed by two of the second sacrificial spacers 20a that are spaced apart from each other.

[0032] A second mask pattern 30 can be formed. The steps of forming the second mask pattern 30 may include: performing a deposition process on the lower structure 5, which has formed the first sacrificial spacer 10a, the second sacrificial spacer 20a, and the first remaining mask pattern 15b, to conformally form a mask material layer; and anisotropically etching the mask material layer. In order to form the second mask pattern 30, the first remaining mask pattern 15b is partially etched while etching the mask material layer, so that the height of the first remaining mask pattern 15b can be reduced.

[0033] The second mask pattern 30 may be formed of the same material as the first residual mask pattern 15b. The second mask pattern 30 may be formed having a reference value equal to or greater than the above. Figure 1 and Figure 2 The thickness ta1 and thickness ta2 of the first mask layer 15 are described.

[0034] The second mask pattern 30 may include a first pattern 30a formed on the side surfaces of two second sacrificial spacers 20a (divided from a second sacrificial pattern 20) and a second pattern 30b formed between two first sacrificial spacers 10a divided from a first sacrificial pattern 10.

[0035] The first pattern 30a of the second mask pattern 30 may contact the horizontal portion 15b1 of the first remaining mask pattern 15b. The second pattern 30b of the second mask pattern 30 may be spaced apart from the first remaining mask pattern 15b.

[0036] Each of the first patterns 30a of the second mask pattern 30 may have an upper surface that decreases in height or height from a portion of its contact with the second sacrificial spacer 20a. Therefore, the first patterns 30a of the second mask pattern 30 may have an asymmetrical side structure, that is, opposite sidewalls with unequal heights.

[0037] The second pattern 30b of the second mask pattern 30 may be a gap-filling pattern that fills the gap between the two first sacrificial spacers 10a, and the second pattern 30b may include side surfaces with a symmetrical structure, that is, opposite sidewalls with equal height.

[0038] The vertical portion 15b2 of each of the first remaining mask patterns 15b can be formed between a pair of second mask patterns 30.

[0039] Reference Figure 9 and Figure 10B A third sacrificial spacer 35 may be formed to fill the space between the first patterns 30a of the second mask pattern 30. The step of forming the third sacrificial spacer 35 may include: forming a sacrificial material layer on the lower structure 5 on which the second mask pattern 30 is formed; and partially etching the sacrificial material layer to expose the first remaining mask pattern 15b and the second mask pattern 30. The third sacrificial spacer 35 may be formed of the same material as the first sacrificial spacer 10a and the second sacrificial spacer 20a.

[0040] Reference Figure 11 and Figure 12A The upper spacer 25 can be removed to expose the first sacrificial spacer 10a and the second sacrificial spacer 20a. The first sacrificial spacer 10a, the second sacrificial spacer 20a and the third sacrificial spacer 35 can reduce or prevent the collapse of the first remaining mask pattern 15b and the second mask pattern 30.

[0041] Reference Figure 11 and Figure 12B The first sacrificial spacer 10a, the second sacrificial spacer 20a, and the third sacrificial spacer 35 can be selectively removed. The first remaining mask pattern 15b and the second mask pattern 30 can be retained.

[0042] Reference Figure 13 and Figure 14 The first remaining mask pattern 15b and the second mask pattern 30 can be etched anisotropically. As a result, the height of the first remaining mask pattern 15b, which has an "L" shape, can be reduced or decreased to form a first mask pattern 15c, which has an "I" shape. The height of the second mask pattern 30, which has an "I" shape, can also be reduced or decreased. Therefore, the first mask pattern 15c and the second mask pattern 30 can be formed to have an "I" shape. A trimming pattern 40 can be formed to expose the edge areas of the first mask pattern 15c and the second mask pattern 30.

[0043] Reference Figure 15 and Figure 16 The first mask pattern 15c and the second mask pattern 30 can be formed in a linear or stripe manner, using the trimming pattern 40 (see Figure 13 and Figure 14 The first mask pattern 15c and the edge regions of the second mask pattern 30 are etched using an etching mask. In an illustrative example, the trimmed pattern 40 (see...) Figure 13 and Figure 14 This can be a photoresist pattern. Alternatively, the pattern 40 can be trimmed (see...). Figure 13 and Figure 14This can be a sacrificial pattern patterned through photolithography. Next, the trimmed pattern 40 can be removed (see...). Figure 13 and Figure 14 ).

[0044] As described above, a first mask pattern 15c and a second mask pattern 30 having a linear or stripe shape can be provided. Next, a method for forming a semiconductor device using the first mask pattern 15c and the second mask pattern 30 will be described. Figure 17A and Figure 17B This is a cross-sectional view illustrating an example of a method for forming a semiconductor device according to an embodiment.

[0045] Reference Figure 17A , refer to the above Figures 1 to 16 The described lower structure 5 can be a lower structure 105 such as a semiconductor substrate. The first mask pattern 15c and the second mask pattern 30 described above can be formed on the lower structure 105. The trench 105t can be formed by etching the lower structure 105 using the first mask pattern 15c and the second mask pattern 30 as etching masks.

[0046] In the example, when the current structure 105 is a semiconductor substrate, the portion 105a of the semiconductor substrate 105 left below the first mask pattern 15c and the second mask pattern 30 provided during the formation of the trench 105t can be an active region. Therefore, a portion 105a of the semiconductor substrate 105 defined by the trench 105t, for example, an active region, can be formed.

[0047] Reference Figure 17B A gap-fill pattern 120 can be formed to fill the trench 105t. The step of forming the gap-fill pattern 120 may include: forming a gap-fill material layer on the semiconductor substrate 105 on which the trench 105t is formed; and planarizing the gap-fill material layer. The first mask pattern 15c and the second mask pattern 30 may be removed simultaneously with or after planarizing the gap-fill material layer. Thus, a gap-fill pattern 120 remaining in the trench 105t can be formed.

[0048] In the example, when the portion 105a of the semiconductor substrate 105 defined by the trench 105t is an active region, the gap fill pattern 120 may be an isolation region formed of an insulating material such as silicon oxide. The first mask pattern 15c and the second mask pattern 30 may be removed simultaneously with or after the formation of the isolation region 120.

[0049] Figures 18A to 18C This is a cross-sectional view illustrating another example of a method for forming a semiconductor device according to some embodiments.

[0050] Reference Figure 18A , refer to the above Figures 1 to 16The described lower structure 5 may be a lower structure 5a comprising a semiconductor substrate 150, an insulating layer 155 on the semiconductor substrate 150, a conductive layer 160 on the insulating layer 155, and a capping insulating layer 165 on the conductive layer 160. The capping insulating layer 165 may be formed of a material having etch selectivity relative to the first mask pattern 15c and the second mask pattern 30, for example, formed of silicon nitride. The conductive layer 160 may be formed of a conductive material that can be used as a gate electrode of a semiconductor device or a conductive material that can be used as wiring of a semiconductor device. For example, the conductive layer 160 may be formed of a polysilicon layer, a metal nitride layer such as TiN or TaN, or a metal such as tungsten (W), copper (Cu), or a combination thereof.

[0051] Reference above Figures 1 to 16 The first mask pattern 15c and the second mask pattern 30 described herein can be formed on the lower structure 5a.

[0052] Reference Figure 18B The first mask pattern 15c and the second mask pattern 30 can be used as etching masks to etch the capping insulating layer 165 of the structure 5a to form the capping insulating pattern 165a.

[0053] In the example, the first mask pattern 15c and the second mask pattern 30 can be etched and removed simultaneously with the formation of the capping insulating pattern 165a, but some embodiments are not limited to this. For example, the first mask pattern 15c and the second mask pattern 30 can be retained after the formation of the capping insulating pattern 165a.

[0054] Reference Figure 18C The conductive pattern 160a can be formed by etching the conductive layer 160 using the capping insulating pattern 165a as an etching mask. Therefore, the lower structure 5a may include the conductive pattern 160a and the capping insulating pattern 165a, which can be formed by patterning using the first mask pattern 15c and the second mask pattern 30, and thus stacked in sequence.

[0055] In the example, conductive pattern 160a can be the gate electrode of a semiconductor device.

[0056] In the illustrative example, conductive pattern 160a can be wiring for a semiconductor device.

[0057] In an illustrative example, conductive pattern 160a may be a bit line of a memory semiconductor device such as dynamic random access memory (DRAM).

[0058] Refer to Figure 13 and Figure 14 As described above, in order to form a first mask pattern 15c and a second mask pattern 30 having a linear or stripe shape, a trimming pattern can be formed. Figure 13 and Figure 14The trimming pattern 40 is used to cut a portion of the first mask pattern 15c and the second mask pattern 30. The trimming pattern 40 can be formed after the first mask pattern 15c and the second mask pattern 30 are formed, but some embodiments are not limited thereto. Hereinafter, reference will be made to... Figure 19 , Figure 20 and Figure 21 Describe the formation of the trimming pattern ( Figure 13 and Figure 14 Example of the operation in 40) being modified. Figure 19 This is to show the above Figure 12A The cross-sectional structure also includes a plan view of the trimmed pattern 170. Figure 20 It shows along Figure 19 A sectional view of the area intercepted by line I-I'. Figure 21 It shows the use of Figure 19 The plan view of the patterned structure of the trimmed pattern 170 in the plan view.

[0059] Reference Figure 19 and Figure 20 The trimming pattern 170 can be formed on the lower structure 5, which includes the first to third sacrificial spacers 10a, 20a and 35. The trimming pattern 170 can be formed by photoresist patterning.

[0060] Reference Figure 21 and Figure 12A The first sacrificial spacers to the third sacrificial spacers 10a, 20a and 35, the first remaining mask pattern 15b and the second mask pattern 30 can be etched using the trimmed pattern 170 as an etching mask, and then the trimmed pattern 170 can be removed. Next, the first sacrificial spacers to the third sacrificial spacers 10a, 20a and 35 can be removed.

[0061] In the resulting product, the first residual mask pattern 15b and the second mask pattern 30 are anisotropically etched to form a shape having the same shape as the reference pattern. Figure 15 and Figure 16 The same "I"-shaped first mask pattern 15c and second mask pattern 30.

[0062] Next, refer to Figures 22 to 33 Examples of modifications to a semiconductor device formation method according to some embodiments are described. Figures 22 to 33 middle, Figure 22 , Figure 24 , Figure 26 , Figure 28 , Figure 30 and Figure 32 This is a plan view illustrating an example of a method for forming a semiconductor device according to some embodiments, and Figure 23 , Figure 25A , Figure 25B , Figure 25C , Figure 27 , Figure 29A , Figure 29B , Figure 31A , Figure 31B and Figure 33 It is along Figure 22 , Figure 24 , Figure 26 , Figure 28 , Figure 30 and Figure 32 The sectional view taken from line I II I' of the plan view.

[0063] Reference Figure 22 and Figure 23 The first sacrificial pattern 210 may be formed on the lower structure 205. The first sacrificial pattern 210 may be formed as having a linear shape. The first sacrificial pattern 210 may be formed from a spin-coated hard mask (SOH) material. For example, the first sacrificial pattern 210 may be formed from a carbon-containing material. The steps of forming the first sacrificial pattern 210 may include: forming a sacrificial material layer on the lower structure 205; and patterning the sacrificial material layer using photolithography.

[0064] A first mask layer 215 may be conformally formed on a lower structure 205 having a first sacrificial pattern 210. For example, the first mask layer 215 may extend over, or cover, the upper and side surfaces of the respective first sacrificial patterns 210 and the portion of the lower structure 205 located between the first sacrificial patterns 210. In this example, the first mask layer 215 may be formed by reference to... Figure 1 and Figure 2 The first mask layer described ( Figure 1 and Figure 2 The material in 15) is the same as the material in the formation.

[0065] The first sacrificial pattern 210 may be formed with a first pitch Pb. Each of the first sacrificial patterns 210 may have a first width Wb. The first sacrificial patterns 210 may be spaced apart from each other by a first distance Sb. The ratio of the first width Wb to the first distance Sb may be about 5 to 7. The sum of the first width Wb and the first distance Sb may be the first pitch Pb. The first thickness tb1 of the first mask layer 215 may be about one-fifth of the first width Wb.

[0066] Reference Figure 24 and Figure 25AThe second sacrificial pattern 220 may be formed on the first mask layer 215 to fill the space between the first sacrificial patterns 210. The step of forming the second sacrificial pattern 220 may include: forming a sacrificial material layer on the first mask layer 215; and etching the sacrificial material layer until the first mask layer 215 located on the first sacrificial pattern 210 is exposed.

[0067] Reference Figure 24 and Figure 25B The portion of the first mask layer 215 located on the first sacrificial pattern 210 can be removed to expose the upper surface of the first sacrificial pattern 210. The first mask layer 215 can be formed as a first residual mask layer 215a located between the first sacrificial patterns 210 and below the second sacrificial pattern 220.

[0068] Processes can be performed to reduce or decrease the height of the first sacrificial pattern 210 and the second sacrificial pattern 220. For example, the capping layer ( Figure 4B 22) can be followed and referenced Figure 4B The same or similar manner described is formed by extending over or covering the first sacrificial pattern 210 and the second sacrificial pattern 220, and the capping layer ( Figure 4B 22) and the first sacrificial pattern 210 and the second sacrificial pattern 220 can be etched sequentially according to the reference. Figure 4C The first sacrificial pattern 210 and the second sacrificial pattern 220 are formed in the same or similar manner to reduce the height, thereby exposing the upper region of the first remaining mask layer 215a.

[0069] Reference Figure 24 and Figure 25C Next, the upper spacer 225 can be aligned with the reference. Figure 6 The upper spacer 225 is formed on the side surface of the upper region of the first residual mask layer 215a in the same or similar manner as described. The upper spacer 225 may be formed on the first sacrificial pattern 210 and the second sacrificial pattern 220, and may extend on or cover the side surface of the upper region of the first residual mask layer 215a.

[0070] Reference Figure 26 and Figure 27 Next, the upper spacer 225 and the first remaining mask layer 215a can be used as etching masks to etch the first sacrificial pattern 210 and the second sacrificial pattern 220. Each of the first sacrificial patterns 210 can be etched and formed as two first sacrificial spacers 210a spaced apart from each other, and each of the second sacrificial patterns 220 can be etched and formed as two second sacrificial spacers 220a spaced apart from each other.

[0071] Reference Figure 28 and Figure 29A It can be followed and referenced Figure 10A A similar manner is described, using the upper spacer 225 as an etching mask to etch the first residual mask layer 215a. As a result, the first residual mask layer 215a having a "U" shape can be formed into a first residual mask pattern 215b having an "L" shape.

[0072] Each of the first remaining mask patterns 215b may include a horizontal portion 215b1 parallel to the upper surface 205s of the lower structure 205 and a vertical portion 215b2 extending from a portion of the horizontal portion 215b1 in a direction perpendicular to the upper surface 205s of the lower structure 205.

[0073] A second mask pattern 230 can be formed. The steps of forming the second mask pattern 230 may include: performing a deposition process on the lower structure 205 on which the first sacrificial spacer 210a, the second sacrificial spacer 220a, and the first remaining mask pattern 215b have been formed, to conformally form a mask material layer; and anisotropically etching the mask material layer. In order to form the second mask pattern 230, the first remaining mask pattern 215b is partially etched together with the etched mask material layer, thereby reducing the height of the first remaining mask pattern 215b.

[0074] The second mask pattern 230 may be formed of the same material as the first residual mask pattern 215b. The second mask pattern 230 may be formed to have a thickness tb2 that is the same as the thickness tb1 of the first mask layer 215, as described above. Figure 22 and Figure 23 The description.

[0075] Each of the second mask patterns 230 may have an upper surface that gradually decreases in height or depth starting from a portion of its contact with the first sacrificial spacer 210a and the second sacrificial spacer 220a. Therefore, the second mask pattern 230 may have an asymmetrical side structure, that is, it has opposing sidewalls of unequal height.

[0076] The second mask pattern 230 may include a first pattern 230a formed on the side surfaces of two second sacrificial spacers 220a divided from a second sacrificial pattern 220 and a second pattern 230b formed between two first sacrificial spacers 210a divided from a first sacrificial pattern 210.

[0077] The first pattern 230a of the second mask pattern 230 may contact the horizontal portion 215b1 of the first remaining mask pattern 215b, and the second pattern 230b of the second mask pattern 230 may be spaced apart from the first remaining mask pattern 215b.

[0078] Reference Figure 28 and Figure 29B A third sacrificial spacer 235 can be formed to fill the space between the second mask patterns 230. The third sacrificial spacer 235 can be formed of the same material as the first sacrificial spacer 210a and the second sacrificial spacer 220a.

[0079] Reference Figure 30 and Figure 31A The upper spacer 225 can be removed to expose the first sacrificial spacer 210a and the second sacrificial spacer 220a.

[0080] Reference Figure 30 and Figure 31B The first sacrificial spacer 210a, the second sacrificial spacer 220a and the third sacrificial spacer 235 can be removed.

[0081] Reference Figure 32 and Figure 33 The first residual mask pattern 215b and the second mask pattern 230 can be etched anisotropically. As a result, the height of the first residual mask pattern 215b, which has an "L" shape, can be reduced or decreased, and it is formed into a first mask pattern 215c, which has an "I" shape. The height of the second mask pattern 230, which has an "I" shape, can also be reduced or decreased. Therefore, the first mask pattern 215c and the second mask pattern 230 can have an "I" shape with a constant or uniform width.

[0082] In some embodiments, the first mask pattern 215c and the second mask pattern 230 may be patterned using the trimming pattern 40, as shown in reference to Figure 13 and Figure 14 The description is as follows. Therefore, the first mask pattern 215c and the second mask pattern 230 can be formed as having a linear or stripe shape.

[0083] In examples, a method of forming a semiconductor device according to some embodiments may include: forming a first sacrificial pattern 10 or 210 on a lower structure 5 or 205; forming a first residual mask layer 15a or 215a having a "U" shape and contacting the first sacrificial pattern 10 or 210 such that it is situated between the first sacrificial patterns 10 or 210; patterning the first residual mask layer 15a or 215a to form a horizontal portion 15b1 or 215b1 parallel to the upper surface of the lower structure 5 or 205 and a vertical portion... The first remaining mask pattern 15b or 215b is formed on the vertical portion 15b2 or 215b2 of the upper surface of the lower structure 5 or 205; a second mask pattern 30 or 230 is formed spaced apart from the vertical portion 15b2 or 215b2 of the first remaining mask pattern 15b or 215b; the remaining first sacrificial pattern 10 or 210 is removed; and the horizontal portion 15b1 or 215b1 of the first remaining mask pattern 15b or 215b is etched to form the first mask pattern 15c or 215c.

[0084] In examples, a method of forming a semiconductor device according to some embodiments may include: forming a first residual mask pattern 15b or 215b on a lower structure 5 or 205, comprising a horizontal portion 15b1 or 215b1 and a vertical portion 15b2 or 215b2, the horizontal portion 15b1 or 215b1 being parallel to the upper surface of the lower structure 5 or 205, and the vertical portion 15b2 or 215b2 extending from some portions of the horizontal portion 15b1 or 215b1 in a direction perpendicular to the upper surface of the lower structure 5 or 205; forming a second mask pattern 30 or 230 on the lower structure 5 or 205; and anisotropically etching the first residual mask pattern 15b or 215b and the second mask pattern 30 or 230. The horizontal portion 15b1 or 215b1 of the first residual mask pattern 15b or 215b may be etched by anisotropic etching to form a first mask pattern 15c or 215c. The second mask pattern 30 or 230 may be formed by a first pattern 30a or 230a that contacts the horizontal portion 15b1 or 215b1 of the first remaining mask pattern 15b or 215b and a second pattern 30b or 230b that is spaced apart from the first remaining mask pattern 15b or 215b.

[0085] In reference Figures 1 to 16 In the described example embodiment, two first mask patterns 15c and three second mask patterns 30 can be formed at a first pitch Pa. Therefore, the first sacrificial pattern 10 can be formed using an exposure apparatus, and by utilizing deposition and etching processes without an exposure apparatus, one (or a pair) of first sacrificial patterns 10 formed at the first pitch Pa can be formed into a total of five mask patterns 15c and 30, as shown. Figure 16 As shown. Therefore, according to the example embodiment, a patterning method can be provided in which the patterning resolution of the exposure device can be further increased by up to five times.

[0086] In reference Figures 22 to 33 In the described example embodiment, two first mask patterns 215c and four second mask patterns 230 can be formed with a first pitch of Pb. Therefore, the first sacrificial pattern 210 can be formed using an exposure apparatus, and by utilizing deposition and etching processes without an exposure apparatus, one (or a pair) of first sacrificial patterns 210 formed with a first pitch of Pb can be formed into a total of six mask patterns 215c and 230, as shown. Figure 33 As shown. Therefore, according to the example embodiment, a patterning method in which the patterning resolution of the exposure device is further increased by up to six times can be provided.

[0087] As in the example embodiment, five or six mask patterns can be formed using a sacrificial pattern with a pitch of Pa or Pb that can be formed by an exposure device. By forming semiconductor devices using mask patterns formed as described above, the integration density of semiconductor devices can be improved.

[0088] As described above, according to the example embodiments, a method for forming fine patterns in which the optical resolution limit of the exposure equipment can be reduced, and a method for forming a semiconductor device using the method for forming fine patterns, can be provided.

[0089] While exemplary embodiments have been shown and described above, those skilled in the art will understand that modifications and changes may be made without departing from the scope of the inventive concept as defined by the appended claims.

Claims

1. A method of forming a semiconductor device, comprising the steps of: forming first sacrificial patterns on an underlying structure; forming a first remaining mask layer extending on sidewalls of the first sacrificial patterns and between the first sacrificial patterns, such that the first remaining mask layer is in contact with the first sacrificial patterns; forming first remaining mask patterns by patterning the first remaining mask layer, the first remaining mask patterns comprising respective horizontal portions parallel to an upper surface of the underlying structure and respective vertical portions perpendicular to the upper surface of the underlying structure; forming second mask patterns spaced apart from the respective vertical portions of the first remaining mask patterns; removing the first sacrificial patterns after forming the second mask patterns; and forming first mask patterns by etching the respective horizontal portions of the first remaining mask patterns, each of the first mask patterns comprising a portion of a respective one of the vertical portions of the first remaining mask patterns. the respective vertical portions of the first remaining mask patterns are arranged between a corresponding pair of the second mask patterns, and wherein the respective horizontal portions of the first remaining mask patterns are in contact with one of the corresponding pair of the second mask patterns but are spaced apart from the other of the corresponding pair of the second mask patterns.

2. The method of claim 1, wherein, the step of forming the first remaining mask layer in contact with the first sacrificial patterns comprises:

3. The method of claim 1, wherein, forming a first mask layer on the underlying structure on which the first sacrificial patterns are formed, at a first thickness, the first mask layer extending on the side portions and the upper surface of the first sacrificial patterns and on the underlying structure between the first sacrificial patterns; forming second sacrificial patterns on the first mask layer between the first sacrificial patterns, wherein the second sacrificial patterns are separated from the underlying structure by the first mask layer extending between the first sacrificial patterns; and removing portions of the first mask layer on the first sacrificial patterns between the second sacrificial patterns. each of the first sacrificial patterns has a first width, 4. The method of claim 3, wherein, the first sacrificial patterns are spaced apart from each other by a first distance greater than the first width, and the first thickness is less than the first width. the step of forming the first remaining mask patterns by patterning the first remaining mask layer comprises:

5. The method of claim 3, wherein, etching the first sacrificial patterns and the second sacrificial patterns to expose an upper region of the first remaining mask layer; forming upper spacers on the side portions of the upper region of the first remaining mask layer; etching the first sacrificial patterns and the second sacrificial patterns by using the first remaining mask layer and the upper spacers as etch masks; and anisotropically etching the first remaining mask layer by using the etched first sacrificial patterns and second sacrificial patterns as etch masks to form the first remaining mask layer in a "U” shape into the first remaining mask patterns in an "L” shape. the step of forming the second mask patterns spaced apart from the respective vertical portions of the first remaining mask patterns comprises:

6. The method of claim 5, wherein, ​ forming a layer of mask material having a thickness equal to a first thickness of the first mask layer, the layer of mask material having a same material as a material of the first mask layer; and anisotropically etching the layer of mask material.

7. The method of claim 6, further comprising the step of:

8. The method of claim 7, wherein, forming the second mask pattern after forming the first mask pattern, the second mask pattern being formed simultaneously with the first mask pattern. forming the first mask pattern includes: anisotropically etching the "L" shaped first remaining mask pattern after removing the first and second sacrificial patterns.

9. The method of claim 1, further comprising the steps of: forming an isolation region in the trench, wherein forming trenches defining active regions by etching the lower structure using the first and second mask patterns as etch masks; and 10. The method of claim 1, wherein, removing the first and second mask patterns simultaneously with forming the isolation regions or after forming the isolation regions. the lower structure includes conductive layers and a capping insulating layer stacked in order.

11. The method of claim 10, further comprising the steps of: forming a capping insulating pattern remaining under the first and second mask patterns by etching the capping insulating layer using the first and second mask patterns as etch masks; and wherein forming a conductive pattern by etching the conductive layers under the capping insulating pattern, the first and second mask patterns are removed simultaneously with forming the capping insulating pattern or after forming the capping insulating pattern.

12. A method of forming a semiconductor device, comprising the steps of: forming first sacrificial patterns on a lower structure, each of the first sacrificial patterns having a first width and the first sacrificial patterns being spaced apart from each other by a first distance greater than the first width; forming first remaining mask patterns between and in contact with the first sacrificial patterns, the first remaining mask patterns including respective horizontal portions parallel to an upper surface of the lower structure and respective vertical portions perpendicular to the upper surface of the lower structure; forming second mask patterns spaced apart from the respective vertical portions of the first remaining mask patterns; removing the first sacrificial patterns remaining after forming the second mask patterns; and 13. The method of claim 12, wherein, forming first mask patterns by anisotropically etching the first remaining mask patterns, each of the first mask patterns including a portion of a respective one of the vertical portions of the first remaining mask patterns.

14. The method of claim 12, wherein, the first and second mask patterns are formed of a same material and are formed to have a same width. forming the first remaining mask patterns in contact with the first sacrificial patterns includes: forming a first mask layer on the first sacrificial patterns at a first thickness, the first mask layer extending over side portions and an upper surface of the first sacrificial patterns and over an upper surface of the lower structure between the first sacrificial patterns; forming a second sacrificial pattern on the first mask layer between the first sacrificial patterns, wherein the second sacrificial pattern is separated from the upper surface of the underlying structure by the first mask layer on the upper surface of the underlying structure between the first sacrificial patterns; and removing portions of the first mask layer on the first sacrificial patterns between the second sacrificial patterns.

15. The method of claim 14, wherein, a ratio of a size of the first width to a size of the first distance is 3 to 7, and wherein the first thickness is one third of the size of the first width.

16. The method of claim 14, wherein, a ratio of a size of the first width to a size of the first distance is 5 to 7, and wherein the first thickness is one fifth of the size of the first width.

17. The method of claim 12, wherein, prior to forming the first mask pattern, the second mask pattern includes a first pattern in contact with the respective horizontal portions of the first remaining mask pattern and a second pattern spaced apart from the respective horizontal portions of the first remaining mask pattern.

18. A method of forming a semiconductor device, comprising the steps of: forming a first remaining mask pattern on an underlying structure, the first remaining mask pattern including respective horizontal portions parallel to an upper surface of the underlying structure and respective vertical portions extending from the respective horizontal portions in a direction perpendicular to the upper surface of the underlying structure; after forming the first remaining mask pattern, forming a second mask pattern on the underlying structure, wherein the second mask pattern includes a first pattern in contact with the respective horizontal portions of the first remaining mask pattern and a second pattern spaced apart from the first remaining mask pattern; and performing an anisotropic etch on the first remaining mask pattern and the second mask pattern, wherein the respective horizontal portions of the first remaining mask pattern are etched by the anisotropic etch to define first mask patterns, and each of the first mask patterns includes a portion of a respective one of the vertical portions of the first remaining mask pattern.

19. The method of claim 18, wherein, the steps of forming a first remaining mask pattern and a second mask pattern on the underlying structure include: forming first sacrificial patterns on the underlying structure, each of the first sacrificial patterns having a first width, the first sacrificial patterns spaced apart from each other by a first distance greater than the first width; forming a first mask layer on the underlying structure on which the first sacrificial patterns are formed, the first mask layer having a first thickness less than the first width; forming a second sacrificial pattern on the first mask layer between the first sacrificial patterns; forming a first remaining mask layer by removing portions of the first mask layer on the first sacrificial patterns between the second sacrificial patterns; etching the first sacrificial patterns and the second sacrificial patterns to expose an upper region of the first remaining mask layer; forming an upper spacer on the first sacrificial patterns and the second sacrificial patterns such that the upper spacer extends on sides of the upper region of the first remaining mask layer; forming first sacrificial spacers and second sacrificial spacers by etching the first sacrificial patterns and the second sacrificial patterns using the first remaining mask layer and the upper spacer as etch masks; etching the first remaining mask layer by an anisotropic etching process using the upper spacers as etching masks to form the first remaining mask pattern; forming second mask patterns on side portions of the first and second sacrificial spacers; and removing the upper spacers and the first and second sacrificial spacers.

20. The method of claim 19, wherein: in response to etching of the first and second sacrificial patterns using the first remaining mask layer and the upper spacers as etching masks, each of the first sacrificial patterns defines two of the first sacrificial spacers that are spaced apart from each other, and each of the second sacrificial patterns defines two of the second sacrificial spacers that are spaced apart from each other; a first one of the second mask patterns is formed on a respective side portion of each of the two of the second sacrificial spacers and is in contact with a respective horizontal portion of the first remaining mask pattern; and a second one of the second mask patterns is spaced apart from the respective horizontal portion of the first remaining mask pattern while the second one of the second mask patterns is formed between the two of the first sacrificial spacers.

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