Method for cutting fin structures

Abstract

The present invention discloses a method for cutting a fin-like structure, comprising the following steps. First, a photomask is provided, wherein the photomask includes a serpentine pattern. Next, a photoresist layer is formed to cover the fin-like structure, wherein the fin-like structure is located on a substrate. Thereafter, exposure and development are performed to form a photoresist pattern in the photoresist layer, wherein the photoresist pattern corresponds to the serpentine pattern. The photoresist pattern is then transferred and the cut portion of the fin-like structure is etched to cut the fin-like structure.

Description

Technical Field

[0001] The present invention relates to a method for cutting a fin-shaped structure, and in particular to a method for cutting a fin-shaped structure by using a photomask with a serpentine pattern. Background Art

[0002] As semiconductor device sizes shrink, maintaining the performance of small-sized semiconductor devices is a primary goal in the industry. To improve semiconductor device performance, various multi-gate field-effect transistors (multi-gate MOSFETs) have been developed. Multi-gate MOSFETs offer several advantages. First, their fabrication process can be integrated with traditional logic device fabrication processes, resulting in significant fabrication process compatibility. Second, their three-dimensional structure increases the contact area between the gate and the substrate, enhancing the gate's control over the charge in the channel region, thereby reducing the drain-induced barrier lowering (DIBL) and short channel effects associated with small-sized devices. Furthermore, since a gate of the same length has a larger channel width, the current flow between the source and drain can be increased. The three-dimensional structure of a multi-gate MOSFET consists of a fin-shaped structure formed in the substrate, with the gate positioned above the fin. The fabrication process also includes a fin-cutting process to complete the layout of the various components in the integrated circuit. Summary of the Invention

[0003] The present invention provides a method for cutting a fin-shaped structure, wherein the method uses a photomask including a serpentine pattern to cut the fin-shaped structure to avoid exposure defects.

[0004] The present invention provides a method for cutting a fin-like structure, comprising the following steps. First, a photomask is provided, wherein the photomask includes a serpentine pattern. Next, a photoresist layer is formed to cover the fin-like structure, wherein the fin-like structure is located on a substrate. Thereafter, exposure and development are performed to form a photoresist pattern in the photoresist layer, wherein the photoresist pattern corresponds to the serpentine pattern. The photoresist pattern is then transferred and the cut portion of the fin-like structure is etched to cut the fin-like structure.

[0005] Based on the above, the present invention provides a method for cutting a fin structure, comprising: applying a photomask with a serpentine pattern, forming a photoresist layer covering the fin structure on a substrate, performing exposure and development to form a photoresist pattern in the photoresist layer corresponding to the serpentine pattern of the photomask, and transferring the photoresist pattern and etching the cut portion of the fin structure, thereby cutting the fin structure. The serpentine pattern of the present invention can avoid problems such as exposure failure or overexposure of individual island or dot patterns, thereby improving the cutting defects of the fin structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 A schematic flow chart of a method for cutting a fin-shaped structure in a preferred embodiment of the present invention;

[0007] Figure 2 Schematic diagram of the layout of the photomask relative to the fin structure in the method for cutting the fin structure in a preferred embodiment of the present invention;

[0008] Figure 3 Schematic top view of a photoresist layer covering a fin structure in a method for cutting a fin structure in a preferred embodiment of the present invention;

[0009] Figure 4 is a schematic top view of the fin structure after cutting in a preferred embodiment of the present invention;

[0010] Figure 5 Schematic diagram of the layout of the photomask relative to the fin structure in the method for cutting the fin structure in another preferred embodiment of the present invention.

[0011] Description of main component symbols

[0012] 10, 10a: Photomask

[0013] 12, 12a, 12b, 12c: Snake pattern

[0014] 20: Photoresist layer

[0015] 22: Photoresist pattern

[0016] 110: Base

[0017] 112, 112a: Fin-shaped structure

[0018] 112c, 112ca, 112cb, 112cc: Cutting part

[0019] c: curved part

[0020] i: Island pattern

[0021] θ: bending angle

[0022] S1, S2, S3, S4: Steps DETAILED DESCRIPTION

[0023] Figure 1 FIG. 4 is a flow chart illustrating a method for cutting a fin-shaped structure according to a preferred embodiment of the present invention. Figure 2 A schematic diagram illustrating the layout of the photomask relative to the fin structure in the method for cutting the fin structure in a preferred embodiment of the present invention is shown. Figure 1 and Figure 2 .in accordance with Figure 1 A step S1 of providing a photomask, wherein the photomask includes a serpentine pattern, provides a layout diagram of the photomask 10 relative to the fin structure 112, as shown in FIG. Figure 2 As shown. The fin structure 112 is located on a substrate 110. The method of forming the fin structure 112 may be, for example, first providing a block substrate (not shown), forming a hard mask layer (not shown) on the block substrate, and patterning the hard mask layer to define the position of the fin structure to be formed in the block substrate below. Then, an etching process is performed to form the fin structure 112 in the block substrate (not shown). In this way, the production of the fin structure 112 on the substrate 110 is completed. In one embodiment, the hard mask layer is removed after the fin structure 112 is formed, but the method of forming the fin structure 112 is not limited thereto.

[0024] In this embodiment, the photomask 10 includes a serpentine pattern 12 corresponding to the fin structure 112 to be cut. Figure 2 As shown, the portion of the fin structure 112 that overlaps with the serpentine pattern 12 is the cut portion 112c to be removed. In other words, the serpentine pattern 12 includes a plurality of island patterns i, wherein the island pattern i is used to correspond to the cut portion 112c of the fin structure 112 to be removed. Alternatively, the serpentine pattern 12 can be considered to include a bent portion c, wherein the bent portion c has different bending angles θ to respectively connect the island patterns i. The bending angle θ depends on the relative position and size of the island pattern i to be connected. Replacing the traditional photomask for cutting the fin structure 112 with only the island pattern i with the serpentine pattern 112 can avoid problems such as exposure failure of individual island patterns i or overexposure removal of adjacent fin structures 112 that do not need to be removed, thereby improving the cutting defects of the fin structure 112.

[0025] In other embodiments, the photomask 10 may further include other patterns. Figure 5 A schematic diagram of the layout of the photomask relative to the fin structure in a method for cutting the fin structure in another preferred embodiment of the present invention is shown. Figure 5 As shown, the photomask 10a includes a plurality of serpentine patterns 12a / 12b / 12c for cutting the fin structures 112a respectively. Figure 5 The serpentine patterns 12a / 12b / 12c can be respectively Figure 2Alternatively, the serpentine patterns 12a / 12b / 12c may be adjusted according to the positions of the to-be-cut portions 112ca / 112cb / 112cc of the fin-shaped structure 112, respectively.

[0026] To simplify the present invention, the following Figure 2 The embodiment of FIG. 1 describes that the pattern of the photomask 10 is transferred to the fin structure 112 via the photoresist layer. Figure 3 A schematic top view of a photoresist layer covering a fin structure in a method for cutting a fin structure in a preferred embodiment of the present invention is shown. Figure 1 Step S2: forming a photoresist layer to cover the fin structure, providing a photoresist layer 20 to cover the fin structure 112, such as Figure 3 shown.

[0027] in accordance with Figure 1 Step S3: performing exposure and development to form a photoresist pattern on the photoresist layer. Figure 3 As shown, exposure and development are performed to form a photoresist pattern 22 on the photoresist layer 20. Since the photoresist layer 20 is used to transfer the pattern of the photomask 10 to the fin structure 112, Figure 2 The pattern of the photomask 10 should be roughly the same as Figure 3 The photoresist layer 20 has the same pattern as that of the photomask 10. In an ideal state, the serpentine pattern 12 of the photomask 10 in this embodiment corresponds to forming the photoresist pattern 22 into a serpentine groove in the photoresist layer 20, but the present invention is not limited thereto. In a preferred embodiment, according to the distribution of the photomask 10 relative to the fin structure 112, the serpentine groove (photoresist pattern) 22 overlaps the cut portion 112c of the adjacent fin structure 112 to cut the fin structure 112. In a more preferred embodiment, the serpentine groove (photoresist pattern) 22 overlaps the cut portion 112c of the adjacent two fin structures 112, so that the cut portions 112c of the two fin structures 112 are removed to cut the two fin structures 112.

[0028] in accordance with Figure 1 Step S4: transferring the photoresist pattern and etching the cut portion of the fin structure to cut the fin structure. Figures 3 and 4 As shown, the photoresist pattern 22 is transferred and the cut portion 112c of the fin structure 112 is etched to remove the cut portion 112c. Subsequently, the photoresist layer 20 is removed, as shown in FIG. Figure 4 As shown, a fin-shaped structure f is formed after cutting.

[0029] In summary, the present invention provides a method for cutting a fin structure, which provides a photomask including a serpentine pattern, forms a photoresist layer covering the fin structure on a substrate, performs exposure and development to form a photoresist pattern corresponding to the serpentine pattern in the photoresist layer, and transfers the photoresist pattern and etches the cut portion of the fin structure, thereby cutting the fin structure. The serpentine pattern can be regarded as including a plurality of island patterns, wherein the island patterns are used to correspond to the cut portion of the fin structure to be removed. Replacing a plurality of individual island patterns with the serpentine pattern of the present invention can avoid problems such as failure of exposure of individual island patterns or overexposure removal of adjacent fin structures that do not need to be removed, thereby improving the cutting defects of the fin structure.

[0030] The above descriptions are merely preferred embodiments of the present invention. All equivalent changes and modifications made according to the claims of the present invention should fall within the scope of the present invention.

Claims

1. A method for cutting a fin-shaped structure, comprising: providing a photomask, wherein the photomask comprises a serpentine pattern; forming a photoresist layer to cover a plurality of fin-shaped structures, wherein the plurality of fin-shaped structures are located on a substrate; Performing exposure and development to form a photoresist pattern on the photoresist layer, wherein the photoresist pattern corresponds to the serpentine pattern and overlaps a plurality of cut portions of the plurality of adjacent fin-shaped structures; as well as The photoresist pattern is transferred and cut portions of the plurality of fin structures are etched to cut the plurality of fin structures. 2 . The method for cutting a fin structure as claimed in claim 1 , wherein the photoresist pattern comprises a serpentine groove formed by the serpentine pattern of the photomask. 3 . The method for cutting a fin-shaped structure as claimed in claim 2 , wherein the serpentine groove overlaps the plurality of cut portions of the adjacent plurality of fin-shaped structures. 4 . The method for cutting a fin-shaped structure as claimed in claim 3 , wherein the serpentine groove overlaps the plurality of cut portions of two adjacent fin-shaped structures, thereby removing the plurality of cut portions of two fin-shaped structures to cut the two fin-shaped structures.

5. The method of cutting fin-shaped structures according to claim 1 , further comprising, after cutting the plurality of fin-shaped structures: The photoresist layer is removed. 6 . The method for cutting a fin-shaped structure as claimed in claim 1 , wherein the photomask comprises a plurality of serpentine patterns for cutting the plurality of fin-shaped structures respectively. 7 . The method for cutting a fin-shaped structure as claimed in claim 1 , wherein the serpentine pattern comprises a plurality of island-shaped patterns, wherein the plurality of island-shaped patterns are used to correspondingly remove the plurality of cut portions of the plurality of fin-shaped structures. 8 . The method for cutting a fin-shaped structure as claimed in claim 7 , wherein the serpentine pattern comprises a plurality of curved portions, wherein the plurality of curved portions have different bending angles to respectively connect the plurality of island-shaped patterns.

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