Method for manufacturing fin portion and semiconductor device

Abstract

The application provides a fin manufacturing method and a semiconductor device. The method comprises the following steps: providing a substrate, forming a groove in the substrate, and performing hydrofluoric acid cleaning; filling an isolation material in the groove to form an isolation structure; and etching the substrate to form a fin line, which is cut by the isolation structure in the extending direction to form a fin. The application forms the groove for cutting the fin line first, fills the isolation structure after the hydrofluoric acid cleaning, and then etches the substrate to form the fin line. The cutting step of the fin line is moved to before the formation of the fin line, and the hydrofluoric acid cleaning process is also moved to before the formation of the fin line. Therefore, the loss of the fin line sidewall size caused by the hydrofluoric acid cleaning can be avoided, and the size of the fin line does not need to be increased when the fin line is etched, so that the process window is expanded.

Description

Technical Field

[0001] This invention relates to the field of integrated circuit manufacturing technology, and in particular to a method for manufacturing fins and a semiconductor device. Background Technology

[0002] With the continuous development of semiconductor technology, traditional planar devices can no longer meet people's needs for high-performance devices. Fin-Field-Effect Transistor (FinFET) is a three-dimensional device, which includes fins formed vertically on the substrate and a high-dielectric-constant metal gate (HKMG) that intersects the fins. This design can significantly improve circuit control and reduce leakage current, while also significantly shortening the gate length of the transistor.

[0003] However, in FinFET technology, the fin cutting step is performed after all the straight fin lines have been etched. The fin cutting process involves hydrofluoric acid cleaning, resulting in a loss of approximately 1 nanometer on the sidewalls of the fin lines. If the final fin size is to meet requirements, the fin size needs to be increased beforehand during etching. This reduces the space available for etching, significantly increasing the challenges of the etching process. The morphology of the fins and the height of the internal and external oxide layers become difficult to control, ultimately affecting electrical properties. Summary of the Invention

[0004] The purpose of this invention is to provide a method for manufacturing fins and a semiconductor device, which moves the cutting step of the fin lines forward to before the formation of the fin lines, avoids the loss of the sidewall dimensions of the fin lines caused by hydrofluoric acid cleaning, and increases the process window.

[0005] To solve the above-mentioned technical problems, the present invention provides a method for manufacturing a fin, comprising the following steps:

[0006] A substrate is provided, a groove is formed in the substrate, and hydrofluoric acid cleaning is performed;

[0007] Fill the groove with insulating material to form an insulating structure; and

[0008] The substrate is etched to form fin lines, which are truncated in the extension direction by the isolation structure to form multiple fins.

[0009] Optionally, the step of forming the groove in the substrate includes:

[0010] A hard mask layer and a patterned photoresist layer are sequentially formed on the substrate;

[0011] Using the patterned photoresist layer as a mask, the hard mask layer is etched to form the patterned hard mask layer;

[0012] Remove the patterned photoresist layer;

[0013] Using the patterned hard mask layer as a mask, a portion of the substrate is etched to form the groove.

[0014] Optionally, the step of filling the groove with insulating material to form an insulating structure includes:

[0015] A insulating material is filled in, which fills the groove and covers the substrate;

[0016] The insulating material and the hard mask layer are planarized to expose the substrate.

[0017] Optionally, before forming the hard mask layer, the method further includes: forming a stop layer on the substrate;

[0018] The isolation material and the hard mask layer are planarized until the stop layer is exposed.

[0019] Optionally, the stop layer is made of silicon nitride, and the hard mask layer is made of silicon oxide.

[0020] Optionally, the insulating material may be formed using a flow-through chemical vapor deposition method.

[0021] Optionally, the insulating material may be made of silicon oxide.

[0022] Optionally, the fin lines can be formed using a self-aligned process.

[0023] Optionally, the bottom of the isolation structure and the bottom of the fin are located in the same plane.

[0024] Accordingly, the present invention also provides a semiconductor device comprising a fin manufactured using the fin manufacturing method described above.

[0025] In summary, the present invention provides a method for fabricating fins and a semiconductor device. First, a groove is formed in a substrate and cleaned with hydrofluoric acid. An isolation material is then filled into the groove to form an isolation structure. Next, the substrate is etched to form fin lines. The fin lines are truncated in their extension direction by the isolation structure to form fins. The present invention first forms a groove for truncating the fin lines, performs hydrofluoric acid cleaning, fills the groove to form an isolation structure, and then etches the substrate to form the fin lines. This moves the fin-cutting step before fin line formation, thus moving the hydrofluoric acid cleaning process before fin line formation. This avoids the loss of fin line sidewall dimensions caused by hydrofluoric acid cleaning, eliminating the need to increase the fin line size during etching, thereby expanding the process window. Attached Figure Description

[0026] Those skilled in the art will understand that the accompanying drawings are provided to better understand the invention and do not constitute any limitation on the scope of the invention.

[0027] Figure 1 This is a flowchart of a method for manufacturing a fin according to an embodiment of the present invention;

[0028] Figure 2-8 This is a schematic diagram of the steps in a method for manufacturing a fin according to an embodiment of the present invention.

[0029] Figures 2 to 8 middle:

[0030] 100 - Substrate; 110 - Stop layer; 120 - Hard mask layer; 130 - Groove; 140 - Isolation material; 150 - Isolation structure; 160 - Fin line hard mask layer; 170 - Fin. Detailed Implementation

[0031] To make the objectives, advantages, and features of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that the drawings are all in a very simplified form and are not drawn to scale, and are only used to facilitate and clarify the explanation of the embodiments of this invention. Furthermore, the structures shown in the drawings are often part of the actual structures. In particular, different figures may emphasize different aspects and may sometimes use different scales.

[0032] As used in this invention, the singular forms “a,” “an,” and “the” include plural objects; the term “or” is generally used to mean “and / or”; the term “a number” is generally used to mean “at least one”; and the term “at least two” is generally used to mean “two or more”. Furthermore, the terms “first,” “second,” and “third” are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as “first,” “second,” or “third” may explicitly or implicitly include one or at least two of that feature, unless otherwise expressly indicated.

[0033] Figure 1 This is a flowchart of a method for manufacturing a fin according to an embodiment of the present invention.

[0034] like Figure 1 As shown, the method for manufacturing the fin includes the following steps:

[0035] S01: Provide a substrate, form a groove in the substrate, and perform hydrofluoric acid cleaning;

[0036] S02: Fill the groove with insulating material to form an insulating structure;

[0037] S03: Etching the substrate to form fin lines, the fin lines being truncated by the isolation structure in the extending direction to form fins.

[0038] Figures 2-8 The diagram below illustrates the structural steps of a fin manufacturing method according to an embodiment of the present invention. The following will be discussed in conjunction with... Figure 1 and Figures 2-8 The method for manufacturing the fin provided in one embodiment of the present invention will be described in detail.

[0039] In step S01, please refer to Figure 2 and Figure 3 As shown, a substrate 100 is provided, in which a groove 130 is formed and subjected to hydrofluoric acid cleaning.

[0040] The substrate 100 can be any suitable substrate material known to those skilled in the art, such as at least one of the following materials: silicon, silicon-on-insulator (SOI), silicon-on-insulator (SSOI), silicon-on-insulator (S-SiGeOI), silicon-on-insulator (SiGeOI), and germanium-on-insulator (GeOI).

[0041] Specifically, firstly, a stop layer 110 and a hard mask layer 120 are formed on the substrate 100. Next, a photoresist layer is formed on the hard mask layer 120, and a patterned photoresist layer is formed through exposure and development. Using the patterned photoresist layer as a mask, the hard mask layer 120 is etched to form a patterned hard mask layer 120. Next, the patterned photoresist layer is removed, and using the patterned hard mask layer 120 as a mask, the stop layer 110 and the substrate 100 are etched to form a plurality of grooves 130 within the substrate 100. Finally, the substrate 100 is cleaned with hydrofluoric acid.

[0042] Figure 4 This is a top view of the structure after the grooves have been formed. Figure 3 yes Figure 4 The cross-sectional view in the X direction, specifically the cross-sectional view at AA′. From Figure 3 and Figure 4 As can be seen, multiple grooves 130 are formed within the substrate 100. The positions of the grooves 130 correspond to the cutting positions of the subsequently formed fin lines. The subsequently formed fin lines extend along the X direction, and the grooves 130 cut off the fin lines in this extending direction. That is to say, before the fin lines are formed, the predetermined positions are cut off and hydrofluoric acid cleaning is performed. At this time, the fin lines have not yet been formed, and the hydrofluoric acid cleaning does not affect the size of the fin lines.

[0043] The stop layer 110 is made of silicon oxide, and the hard mask layer 120 is made of silicon nitride. Both the stop layer 110 and the hard mask layer 120 can be fabricated by chemical vapor deposition (CVD), physical vapor deposition (PVD), atomic layer deposition (ALD), or a combination thereof.

[0044] In step S02, please refer to Figure 5 and Figure 6 As shown, the insulating material 140 is filled in the groove 130 to form an insulating structure 150.

[0045] In this embodiment, specifically, an isolation material 140 is filled, which completely fills the groove 130 and covers the hard mask layer 120. The isolation material 140 is made of silicon oxide and can be formed using flow chemical vapor deposition (FCVD). Of course, in other embodiments, it can also be formed using, for example, chemical vapor deposition (CVD), physical vapor deposition (PVD), atomic layer deposition (ALD), or a combination thereof.

[0046] Next, the isolation material 140 and the hard mask layer 120 are planarized until the stop layer 110 is exposed. Chemical mechanical polishing (CMP) can be used to polish the isolation material 140 and the hard mask layer 120. The isolation material 140 is made of silicon oxide, the hard mask layer 120 is made of silicon oxide, and the stop layer 110 is made of silicon nitride. A suitable polishing slurry can be selected for CMP polishing until the stop layer 110 is exposed. The stop layer 110 prevents damage to the substrate 100 during polishing.

[0047] In step S03, please refer to Figure 7 and Figure 8 As shown, the substrate 100 is etched to form fin lines, which are truncated in the extending direction by the isolation structure 150 to form fin portions 170.

[0048] In this embodiment, a self-aligned process is used to form the fin lines. For example, a fin line hard mask layer 160 is formed on the stop layer 110. Then, multiple layers, such as a first core layer and a second core layer, can be sequentially formed on the fin line hard mask layer 160. Subsequently, the fin line pattern is transferred to the fin line hard mask layer 160 through etching and other steps. Finally, the substrate 100 is etched using the fin line hard mask layer 160 as a mask to form the fin lines. This self-aligned process is well known to those skilled in the art and will not be described in detail here. Of course, other orientations can also be used to form the fin lines, and this invention is not limited to this.

[0049] Figure 8 This is a top view of the structure after the fin lines have been formed. Figure 7 yes Figure 8 The cross-sectional view in the Y direction, specifically the cross-sectional view at BB′. From Figure 7 and Figure 8 As can be seen, the fin lines extend along the X direction, and the isolation structure 150 is located precisely where the fin lines are to be cut off. That is, the fin lines are truncated by the isolation structure 150 in the extending direction to form the fin portion 170. In other words, after the fin lines are formed, since the fin lines are isolated by the isolation structure 150 and the fin portion 170 has already been formed, it is not necessary to cut the fin lines again, nor is it necessary to perform hydrofluoric acid cleaning. Therefore, the sidewall dimensions of the fin lines can be avoided by preventing hydrofluoric acid cleaning from affecting them.

[0050] In this embodiment, the bottom of the isolation structure 150 and the bottom of the fin 170 are located in the same plane to completely cut off the fin lines. Of course, in other embodiments, the bottom of the isolation structure 150 may be lower than the bottom of the fin 170.

[0051] Compared with the prior art, the fin fabrication method provided in this embodiment first forms a groove 130 in the substrate 100 and performs hydrofluoric acid cleaning. An isolation material 140 is then filled into the groove 130 to form an isolation structure 150. Next, the substrate 100 is etched to form fin lines. The fin lines are truncated by the isolation structure 150 in the extension direction X to form fins 170. This invention first forms a groove 130 for truncating the fin lines, performs hydrofluoric acid cleaning, fills the groove to form the isolation structure 150, and then etches the substrate 100 to form the fin lines. This moves the fin line cutting step forward to before the fin line formation, thus also moving the hydrofluoric acid cleaning process before fin line formation. This avoids the loss of fin line sidewall dimensions caused by hydrofluoric acid cleaning, and therefore eliminates the need to increase the fin line size during etching, thereby expanding the process window.

[0052] Accordingly, the present invention also provides a semiconductor device comprising a fin manufactured by the fin manufacturing method described above.

[0053] In summary, the present invention provides a method for fabricating fins and a semiconductor device. First, a groove is formed in a substrate and cleaned with hydrofluoric acid. An isolation material is then filled into the groove to form an isolation structure. Next, the substrate is etched to form fin lines. The fin lines are truncated in their extension direction by the isolation structure to form fins. The present invention first forms a groove for truncating the fin lines, performs hydrofluoric acid cleaning, fills the groove to form an isolation structure, and then etches the substrate to form the fin lines. This moves the fin-cutting step before fin line formation, thus moving the hydrofluoric acid cleaning process before fin line formation. This avoids the loss of fin line sidewall dimensions caused by hydrofluoric acid cleaning, eliminating the need to increase the fin line size during etching, thereby expanding the process window.

[0054] The above description is merely a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of the claims.

Claims

1. A method for manufacturing a fin, characterized in that, Includes the following steps: A substrate is provided, a groove is formed in the substrate, and hydrofluoric acid cleaning is performed; The groove is filled with insulating material to form an insulating structure; as well as The substrate is etched to form fin lines, which are truncated by the isolation structure in the extension direction to form fins; wherein the fin lines are formed using a self-aligned process. The position of the groove corresponds to the cutting position of the fin line. The fin line is cut at a predetermined position before it is formed.

2. The method for manufacturing the fin according to claim 1, characterized in that, The step of forming a groove in the substrate includes: A hard mask layer and a patterned photoresist layer are sequentially formed on the substrate; Using the patterned photoresist layer as a mask, the hard mask layer is etched to form the patterned hard mask layer; Remove the patterned photoresist layer; Using the patterned hard mask layer as a mask, a portion of the substrate is etched to form the groove.

3. The method for manufacturing the fin according to claim 2, characterized in that, The step of filling the groove with insulating material to form an insulating structure includes: A insulating material is filled in, which fills the groove and covers the substrate; The insulating material and the hard mask layer are planarized to expose the substrate.

4. The method for manufacturing the fin according to claim 3, characterized in that, Before forming the hard mask layer, the method further includes: forming a stop layer on the substrate; The isolation material and the hard mask layer are planarized until the stop layer is exposed.

5. The method for manufacturing the fin according to claim 4, characterized in that, The stop layer is made of silicon nitride, and the hard mask layer is made of silicon oxide.

6. The method for manufacturing the fin according to claim 1, characterized in that, The insulating material is formed using a flow-through chemical vapor deposition method.

7. The method for manufacturing the fin according to claim 1, characterized in that, The insulating material contains silicon dioxide.

8. The method for manufacturing the fin according to claim 1, characterized in that, The bottom of the isolation structure and the bottom of the fin are located in the same plane.

9. A semiconductor device, characterized in that, The fins include those manufactured by the method described in any one of claims 1 to 8.

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