Patterning structure and method for manufacturing the same

Abstract

A method for manufacturing a patterned structure includes the following processes. A hard mask layer and a photoresist layer are sequentially stacked in a first direction. The photoresist layer is formed on the hard mask layer. An isotropic etching process is performed on the hard mask layer and the photoresist layer in a second direction perpendicular to the first direction, such that the width of the hard mask layer in the second direction is smaller than the width of the photoresist layer in the second direction. In this way, the thickness and shape of the photoresist layer are less damaged and the size of the hard mask layer is shortened, which is beneficial to precisely reducing the critical dimensions of the subsequently formed structures or components.

Description

Technical Field

[0001] The present invention relates to a patterned structure and a method for manufacturing a patterned structure. Background Art

[0002] For the process of semiconductor structures or semiconductor components, patterning through a mask is a very important and emphasized step. Especially for the formed semiconductor structures or semiconductor components, the size of the mask has a significant correlation with the critical dimension (CD) on the semiconductor structure or semiconductor component.

[0003] One of the problems to be solved by those skilled in the art is how to ensure that the pattern formed by photoresist on the mask is not damaged on the premise of ensuring that the mask size can be reduced. Summary of the Invention

[0004] One aspect of the present invention relates to a method for manufacturing a patterned structure.

[0005] According to an embodiment of the present invention, a method for manufacturing a patterned structure includes the following processes. Stack a hard mask layer and a photoresist layer in sequence in a first direction. The photoresist layer is formed on the hard mask layer. Perform an isotropic etching process on the hard mask layer and the photoresist layer in a second direction perpendicular to the first direction, so that the width of the hard mask layer in the second direction is smaller than the width of the photoresist layer in the second direction.

[0006] According to an embodiment of the present invention, in the step of sequentially stacking a hard mask layer and a photoresist layer upward, the hard mask layer and the photoresist layer are sequentially stacked on a bottom layer. The material of the photoresist layer is the same as that of the bottom layer.

[0007] According to an embodiment of the present invention, the method further includes patterning the hard mask through the photoresist layer.

[0008] In some embodiments, in the step of sequentially stacking a hard mask layer and a photoresist layer in a first direction, the hard mask layer and the photoresist layer are sequentially stacked on a bottom layer, and the bottom layer is a semiconductor material layer. After performing the isotropic etching process, the semiconductor material layer is patterned through the pattern of the patterned hard mask layer.

[0009] According to an embodiment of the present invention, before performing the isotropic etching process, directly etch the photoresist layer and the hard mask layer in the first direction to simultaneously reduce the width of the photoresist layer in the second direction and the width of the hard mask layer in the second direction.

[0010] According to an embodiment of the present invention, the isotropic etching process uses a radical compound.

[0011] According to an embodiment of the present invention, after performing an isotropic etching process, the photoresist layer completely covers the hard mask layer in a first direction.

[0012] According to an embodiment of the present invention, after performing an isotropic etching process, the photoresist layer has a uniform thickness in a first direction.

[0013] One aspect of the present invention relates to a patterned structure. The photoresist layer has a uniform thickness in a first direction.

[0014] According to an embodiment of the present invention, a patterned structure includes a hard mask layer and a photoresist layer. The photoresist layer is stacked on the hard mask layer in a first direction. The width of the hard mask layer in a second direction perpendicular to the first direction is smaller than the width of the photoresist layer in the second direction. The photoresist layer completely covers the hard mask layer in the first direction.

[0015] In one or more embodiments of the present invention, the photoresist layer has a uniform thickness in a first direction.

[0016] In summary, by performing isotropic etching with a high etching selectivity ratio on the side surfaces of the stacked hard mask layer and photoresist layer, it is possible to ensure that the size of the hard mask layer is shortened without damaging the thickness and shape of the photoresist layer, thereby facilitating the reduction of the critical dimensions of the subsequently formed structures or components.

[0017] The above is only used to illustrate the problems to be solved by the present invention, the technical means for solving the problems, and the effects produced thereby, etc. The specific details of the present invention will be described in detail in the following embodiments and related drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The advantages of the present invention and the drawings should be better understood by referring to the following listed embodiments and the accompanying drawings. The descriptions of these drawings are only listed embodiments, so it should not be considered as limiting individual embodiments or the scope of the claims of the invention.

[0019] Figures 1 to 3 A cross-sectional schematic diagram of different processes in a method for manufacturing a structure for patterning according to an embodiment of the present invention;

[0020] Figure 4 A flowchart of a method for manufacturing a patterned structure according to an embodiment of the present invention; and

[0021] Figures 5 to 7 A cross-sectional schematic diagram of different processes in a method for manufacturing a patterned structure according to an embodiment of the present invention.

[0022]

SYMBOL DESCRIPTION

[0023] 100: Patterned structure

[0024] 120: Bottom layer

[0025] 140: Hard mask layer

[0026] 160: Photoresist layer

[0027] 165: Effective photoresist area

[0028] 200: Method

[0029] 210~230: Process

[0030] 300: Patterned structure

[0031] 320: Bottom layer

[0032] 340: Hard mask layer

[0033] 360: Photoresist layer

[0034] 400: Isotropic etching

[0035] D1: Direction

[0036] D2: Direction

[0037] T1: Thickness

[0038] T2: Thickness

[0039] T3: Thickness

[0040] T4: Thickness

[0041] W1: Width

[0042] W2: Width

[0043] W3: Width

[0044] W4: Width Detailed implementation manners

[0045] Examples are given below in conjunction with the accompanying drawings for detailed description. However, the provided examples are not intended to limit the scope covered by the present invention, and the description of the structure operation is not intended to limit the execution order. Any structure formed by recombining elements and having an equivalent effect is within the scope covered by the present invention. In addition, the drawings are for illustrative purposes only and are not drawn to the original size. For ease of understanding, the same or similar elements will be denoted by the same reference numerals in the following description.

[0046] In addition, the terms used throughout the specification and claims, unless otherwise specified, generally have their ordinary meanings as used in the art, in the context of this invention, and in the specific context. Certain terms used to describe this invention will be discussed below or elsewhere in this specification to provide additional guidance to those skilled in the art regarding the description of this invention.

[0047] In this document, terms such as "first", "second", etc. are only used to distinguish elements or methods of operation with the same technical terms, and are not intended to indicate an order or limit this invention.

[0048] In addition, similar terms such as "comprising", "including", "providing", etc. are open-ended limitations in this document, meaning including but not limited to.

[0049] Furthermore, in this document, unless otherwise specifically defined in the context for articles, "a" and "the" can generally refer to a single or multiple. It will be further understood that the terms "comprising", "including", "having", and similar terms used in this document specify the features, regions, integers, steps, operations, elements, and / or components described therein, but do not exclude one or more other features, regions, integers, steps, operations, elements, components, and / or groups thereof described or additional thereto.

[0050] Please refer to Figures 1 to 3 。 Figures 1 to 3 A cross-sectional schematic diagram of different processes in a method for fabricating a structure for patterning according to an embodiment of the present invention is shown.

[0051] As Figure 1 shown, in an embodiment of the present invention, the patterned structure includes a stacked hardmask (HD) layer 140 and a photoresist (PR) layer 160. In a vertical first direction D1, the hardmask layer 140 and the photoresist layer 160 are sequentially stacked on an under layer (UL) 120.

[0052] In some embodiments, the under layer 120 is, for example, a layer of semiconductor material, such as a layer including a silicon substrate. The hardmask layer 140 is formed on the under layer 120, and then the photoresist layer 160 is formed on the hardmask layer 140. In this way, a pattern can be formed on the hardmask layer 140 through the photoresist layer 160, and then the under layer 120 of the semiconductor material can be patterned through the pattern on the hardmask layer 140.

[0053] In some embodiments, the material of the underlying layer 120 is the same as that of the photoresist layer 160 or other photoresist materials. The hard mask layer 140 is formed on the underlying layer 120, and then the photoresist layer 160 is formed on the hard mask layer 140. Thus, a pattern can be formed on the hard mask layer 140 through the photoresist layer 160, and the underlying layer 120 of the photoresist material serves as an extension layer of the photoresist layer 160 to form a further photoresist pattern through the hard mask layer 140.

[0054] For the purpose of simple illustration, the same or similar dimensions, lengths, widths, or thicknesses are denoted by the same or similar reference numerals. In Figures 1 to 3 , the hard mask layer 140 has a thickness T1 in the first direction D1 and a width W1 in the second direction D2, where the second direction D2 is perpendicular to the first direction D1. Similarly, the photoresist layer 160 has a thickness T2 in the first direction D1 and a width W2 in the second direction D2. In the present invention, the first direction D1 refers to the vertical direction of the stack, and the second direction D2 refers to the horizontally extending direction, and the second direction D2 is perpendicular to the first direction D1.

[0055] Figure 2 Continuing Figure 1 . To reduce the size of the hard mask layer 140, a part of the photoresist layer 160 is first removed so that a part of the hard mask layer 140 is exposed and not covered by the photoresist layer 160. The hard mask layer 140 not covered by the photoresist layer 160 can be removed.

[0056] As Figure 2 shown, a part of the photoresist layer 160 is removed, so that the width W2 of the photoresist layer 160 is reduced. Such a manufacturing process can be referred to as a trimming process of the photoresist layer 160. In some embodiments, the trimming process for reducing the width W2 of the photoresist layer 160 can be achieved by plasma. Since the trimming process is achieved by plasma, with the reduction of the width W2, the thickness T2 of the photoresist layer 160 will also decrease accordingly. This may cause the thickness T2 of the photoresist layer 160 to deviate from the designed value.

[0057] Figure 3 Continuing Figure 2 . Based on the photoresist layer 160 with the reduced width W2 after trimming, the exposed part of the hard mask layer 140 can be removed through an etching process. In this embodiment, the part of the hard mask layer 140 not covered by the photoresist layer 160 is removed, and the width W1 of the hard mask layer 140 is reduced to form a patterned structure 100. The patterned structure 100 can be used to pattern the underlying layer 120.

[0058] In some embodiments, the etching of the hard mask layer 140 also acts on the photoresist layer 160. Therefore, accompanying the etching of the hard mask layer 140, the photoresist layer 160 will also be eroded. Since the hard mask layer 140 is etched from the outside to the inside, the erosion of the photoresist layer 160 is also from the outside to the inside. Thus, the photoresist layer 160 will no longer be uniform and will form a protruding hill shape, which is shown by a dashed line in Figure 3 This corresponds to the fact that, for different positions in the second direction D2, the thickness of the effective photoresist region 165 of the photoresist layer 160 will be different. This will cause the pattern on the hard mask layer 140 to deviate from the design when performing further processes on the hard mask layer 140 through the photoresist layer 160 subsequently, resulting in instability of the critical dimension (CD) / IMB corresponding to the pattern on the hard mask layer 140. When patterning is to be performed again according to the hard mask layer 140 to form a semiconductor structure / component, it will also likely deviate from the pre-designed pattern and critical dimension.

[0059] Please refer to Figure 4 and, according to Figure 4 the different processes illustrated, refer to Figures 5 to 7 respectively. Figure 4 The flowchart of method 200 for manufacturing a patterned structure 300 is illustrated according to an embodiment of the present invention. In this embodiment, method 200 includes process 210 to process 230. Figures 5 to 7 The cross-sectional schematic diagrams of different processes in method 200 for manufacturing a patterned structure 300 are illustrated according to an embodiment of the present invention.

[0060] Please also refer to Figure 4 and Figure 5 simultaneously. In process 210, a hard mask layer 340 and a photoresist layer 360 are sequentially formed stacked in a vertical first direction D1. In this embodiment, the hard mask layer 340 and the photoresist layer 360 are sequentially formed on the underlying layer 320.

[0061] In some embodiments, the underlying layer 320 is, for example, a layer of semiconductor material, such as a layer including a silicon substrate. The hard mask layer 340 is formed on the underlying layer 320, and subsequently the photoresist layer 360 is formed on the hard mask layer 340. Thus, a pattern can be formed on the hard mask layer 340 through the photoresist layer 360, and then the underlying layer 320 of semiconductor material can be patterned through the pattern on the hard mask layer 340. And in some embodiments, the material of the underlying layer 320 is a photoresist material, such as the same as the photoresist layer 360, such that after patterning through the hard mask layer 340, the underlying layer 320 of photoresist material serves as an extension layer of the photoresist layer 360, and a further photoresist pattern is formed through the hard mask layer 340.

[0062] In Figures 5 to 7In [the structure], the hard mask layer 340 has a thickness T3 in a vertical first direction D1 and a width W3 in a lateral second direction D2. The second direction D2 is perpendicular to the first direction D1. Similarly, the photoresist layer 360 has a thickness T4 in the first direction D1 and a width W4 in the second direction D2.

[0063] Please return to Figure 5 . In Figure 5 In [the structure], the hard mask layer 340 and the photoresist layer 360 can be formed, for example, by a deposition process. Through subsequent processes of the method 200, the width W3 of the hard mask layer 340 can be reduced to a predetermined thickness, which is half or less than half of the original thickness, so that the size of the hard mask layer 340 is reduced. For example, the width W3 of the hard mask layer 340 is, for example, 40 nanometers when formed, and through subsequent processes of the method 200, the width W3 of the hard mask layer 340 can be reduced to 20 nanometers, but this does not limit the present invention. At the same time, the central portion of the photoresist layer 360 covering the reduced hard mask layer 340 can also be free of the problem of uneven thickness.

[0064] Please also refer to Figure 4 and Figure 6 . In the optional process 220, the widths W3 and W4 of the hard mask layer 340 and the photoresist layer 360 in the second direction D2 perpendicular to the first direction D1 are reduced simultaneously. It should be noted that at this time, the width W3 of the hard mask layer 340 has not been reduced to the designed final thickness. It can be understood that before reducing the hard mask layer 340 to the designed size, the outer part of the hard mask layer 340 can be preliminarily removed first to increase the speed of the overall process.

[0065] As Figure 6 shown, after being designed, after a part of the photoresist layer 360 is removed, the remaining thickness T4 should be sufficient to perform subsequent processes of patterning the hard mask layer 340.

[0066] In some embodiments, etching can be provided in the first direction D1 to directly etch into the photoresist layer 360 and the hard mask layer 340, thereby reducing the width W4 of the photoresist layer 360 and the width W3 of the hard mask layer 340 simultaneously in the second direction D2.

[0067] In some embodiments, the optional process 220 can be implemented by, for example, Figure 2 and Figure 3 . Specifically, a trimming process can be performed on the photoresist layer 360 by plasma, and then the outer exposed hard mask layer 340 can be removed by an etching method. In this way, although the outer part of the photoresist layer 360 may have uneven thickness due to erosion (not shown), the influence on the central portion of the photoresist layer 360 is less, and it can still be ensured that the thickness of the portion of the photoresist layer 360 covering the hard mask layer 340 in the center is substantially uniform.

[0068] In some embodiments, the reduced width of the hard mask layer 340 can be set to be less than a predetermined value, thereby ensuring that the erosion of the photoresist layer 360 is small, so that the non-uniformity of the outer edge of the photoresist layer 360 relative to the central thickness is not obvious, and ensuring that the overall thickness T4 of the photoresist layer 360 still maintains a certain degree of uniformity.

[0069] Please also refer to Figure 4 and Figure 7 . In process 230, isotropic etching 400 is performed on the hard mask layer 340 and the photoresist layer 360 in the second direction D2, so that the width W3 of the hard mask layer 340 is less than the width W4 of the photoresist layer 360. That is, isotropic etching 400 is performed laterally on the stacked hard mask layer 340 and photoresist layer 360.

[0070] Performing isotropic etching 400 can ensure that the reduction in the thickness T3 of the hard mask layer 340 and the thickness T4 of the photoresist layer 360 in the second direction D2 can be uniform. In order to make the width W3 of the hard mask layer 340 less than the width W4 of the photoresist layer 360, the etching selectivity of isotropic etching 400 needs to be set so that the etching rates of isotropic etching 400 for the hard mask layer 340 and the photoresist layer 360 are different.

[0071] Compared with Figure 6 , after going through process 230, Figure 7 the width W4 of the photoresist layer 360 is almost the same, or only slightly reduced.

[0072] As Figure 7 shown, after etching, the width W3 of the hard mask layer 340 is less than the width W4 of the photoresist layer 360. In some embodiments, the width W3 of the hard mask layer 340 is reduced by one-half compared with Figure 5 , which means that the size of the hard mask layer 340 in the second direction D2 is reduced by half.

[0073] Subsequently Figure 6 for the photoresist layer 360 with a uniform thickness, in Figure 7 , through lateral isotropic etching 400, the photoresist layer 360 has an equal thickness T4 in the first direction D1. As mentioned above, since at least the part of the thickness of the hard mask layer 340 covered by the center of the photoresist layer 360 is uniform, the thickness of the photoresist layer 360 covering the hard mask layer 340 in Figure 7 will also be uniform.

[0074] In this way, when subsequently patterning the hard mask layer 340 through the photoresist layer 360, since it is ensured that the thickness of the photoresist layer 360 covering the central part of the hard mask layer 340 is uniform, the effective photoresist region of the photoresist layer 360 can be kept intact, ensuring that the patterning of the hard mask layer 340 can achieve the designed goal. In other words, the edge of the hard mask layer 340 will not have defects during patterning due to the uneven thickness of the photoresist layer 360, and the side effect of the hard mask layer 340 can be improved. This enables the critical dimension of the hard mask layer 340 to be effectively and precisely reduced.

[0075] For the isotropic etching 400 with a high etching selectivity, the etching selectivity of the hard mask layer 340 to the photoresist layer 360 is greater than one, so that more of the hard mask layer 340 is removed during the isotropic etching 400.

[0076] In some embodiments, the isotropic etching 400 with a high etching selectivity in process 230 can be achieved by a neutral, non - ion way. For example, in some embodiments, the isotropic etching 400 with a high etching selectivity in process 230 can, for example, provide a high etching selectivity through a radical compound in an adjustable manner. Such an etching method can peel off the atoms on the surface of the material layer by layer in a monolayer atomic manner with atomic - level precision. However, it should be understood that the present invention does not limit the isotropic etching 400 process used in process 230 in this way. In some embodiments, other isotropic etching techniques that can achieve a high etching selectivity are also included in the present invention. In some embodiments, the isotropic etching 400 with a high etching selectivity includes a neutral, non - ion wet etching method.

[0077] In some embodiments, process 220 and process 230 belong to etchings in different directions, so they need to be processed separately using different machine tools to increase the overall speed of method 200 and save the required time. For example, in some embodiments, in process 220, direct etching can be provided in a first machine tool in a first direction D1 to simultaneously remove the photoresist layer 360 and the hard mask layer 340 on the underlying layer 320; subsequently, the underlying layer 320, the hard mask layer 340, and the photoresist layer 360 are taken out from the first machine tool, and then the stacked underlying layer 320, hard mask layer 340, and photoresist layer 360 are placed with their sides facing up in another second machine tool to perform process 230 to execute the isotropic etching process.

[0078] After going through processes 210 to 230 of method 200, as Figure 7As shown, a patterned structure 300 is formed on a bottom layer 320. In the present embodiment, the patterned structure 300 includes a hard mask layer 340 and a photoresist layer 360. The photoresist layer 360 is stacked on the hard mask layer 340 in a first direction D1. The width W3 of the hard mask layer 340 in a second direction D2 is smaller than the width W4 of the photoresist layer 360 in the second direction D2, such that the photoresist layer 360 completely covers the hard mask layer 340 in the first direction D1.

[0079] In the case where the hard mask layer 340 is completely covered by the photoresist layer 360 in the first direction D1, in some embodiments, it is also possible to plan to use a hard mask layer 340 with a high thickness.

[0080] As Figure 7 shown, the photoresist layer 360 of the patterned structure 300 has a uniform thickness T4 in the first direction D1. In some embodiments, the photoresist layer 360 has a uniform thickness at least in the central portion covering the hard mask layer 340.

[0081] In some embodiments, the bottom layer 320 is, for example, a layer of semiconductor material, and can perform patterning through the hard mask layer 340 with reduced dimensions to form a semiconductor structure or element, and the formed semiconductor structure or element can have a critical dimension that conforms to the design. In some embodiments, the semiconductor structure formed by patterning through the hard mask layer 340 is, for example, the patterning of a wire or an interconnect structure. In some embodiments, the patterned structure 300 can be applied to the patterning process of a wire or an interconnect structure of a multi layer reticle (MLR), so that the line width of the formed wire or interconnect structure can be appropriately and precisely reduced according to the design, and the overall critical dimension can be reduced.

[0082] In some embodiments, the bottom layer 320 can be a photoresist material to serve as an extension layer of the photoresist layer 360 and be used as a further photoresist after patterning through the hard mask layer 340.

[0083] In summary, the present invention provides a patterned structure for patterning and a manufacturing method of the patterned structure. By performing isotropic etching with a high etching selectivity ratio on the side surfaces of the stacked hard mask layer and photoresist layer, it is possible to ensure that the size of the hard mask layer is shortened without damaging the thickness and shape of the photoresist layer, thereby facilitating the reduction of the critical dimension of the subsequently formed structure or element, or facilitating the formation of an extension layer of the photoresist material.

[0084] Although the present invention has been described above in terms of embodiments, it is not intended to limit the present invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the scope defined in the claims.

Claims

1. A method for manufacturing a patterned structure, characterized in that, Comprising: Stacked in sequence on a bottom layer in a first direction to form a hard mask layer and a photoresist layer, wherein the photoresist layer is formed on the hard mask layer; Performing an isotropic etching process on the hard mask layer and the photoresist layer in a second direction perpendicular to the first direction, such that a first width of the hard mask layer in the second direction is smaller than a second width of the photoresist layer in the second direction, wherein the isotropic etching process performed on the hard mask layer and the photoresist layer is neutral and non-ionic, and the hard mask layer has an equal first width in the second direction; After performing the isotropic etching process on the hard mask layer and the photoresist layer, patterning the hard mask layer through the photoresist layer; And Patterning the bottom layer through the pattern of the patterned hard mask layer.

2. The method according to claim 1, wherein The material of the photoresist layer is the same as that of the bottom layer.

3. The method according to claim 1, wherein The bottom layer is a semiconductor material layer.

4. The method according to claim 1, characterized in that, Before performing the isotropic etching process, etching the photoresist layer and the hard mask layer in the first direction to simultaneously reduce the width of the photoresist layer in the second direction and the width of the hard mask layer in the second direction.

5. The method according to claim 1, characterized in that, The isotropic etching process uses a radical compound.

6. The method according to claim 1, wherein After performing the isotropic etching process, the photoresist layer completely covers the hard mask layer in the first direction.

7. The method according to claim 1, characterized in that After performing the isotropic etching process, the photoresist layer has an equal thickness in the first direction.

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