Method of patterning

Abstract

The application provides a patterning method, which comprises the following steps: forming a sacrificial layer on a target layer to be etched, wherein the sacrificial layer is a low-density carbon film; forming a hard mask layer with SiOCN as a material on the sacrificial layer; forming an etching pattern on the sacrificial layer and the hard mask layer; and etching the target layer by using the formed etching pattern. The application can improve the etching characteristics of the film above the layer to be etched, and obtain a substantially vertical sidewall.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing technology, and more particularly to a patterning method. Background Technology

[0002] As the size of semiconductor devices continues to shrink, the process of patterning thin films becomes increasingly challenging. Improving etching processes is essential to create these minute patterns.

[0003] Currently, commonly used etching methods form amorphous carbon films and SiON layers on the material to be etched. However, during etching, the inventors discovered that it is difficult to obtain vertical sidewalls, which is very disadvantageous for forming small-sized patterns. Summary of the Invention

[0004] To address the above problems, the present invention provides a patterning method that can improve the thin film etching characteristics above the layer to be etched, resulting in substantially vertical sidewalls.

[0005] This invention provides a patterning method, comprising:

[0006] A sacrificial layer is formed on the target layer to be etched, the sacrificial layer being a low-density carbon film;

[0007] A hard mask layer made of SiOCN is formed on the sacrificial layer;

[0008] An etching pattern is formed on the sacrificial layer and the hard mask layer;

[0009] The target layer is etched using the formed etching pattern.

[0010] Optionally, the sacrificial layer is formed by PECVD, including:

[0011] A first reaction gas containing carbon and hydrogen, along with an inert gas, is introduced into the reaction chamber. The gas flow rate is controlled at 10–5000 sccm, the temperature at 100–800℃, and the pressure at 1–100 Torr.

[0012] Optionally, the first reactant gas may be any one of C3H6, C2H4, C2H2, C2H6, and C3H8.

[0013] Alternatively, the inert gas may be any one of argon (Ar), helium (He), and chlorine (Cl).

[0014] Optionally, the hard mask layer is formed by PECVD, including:

[0015] A second reaction gas containing silicon, oxygen, carbon, and nitrogen, as well as ammonia (NH3), is introduced into the reaction chamber. The flow rate of the second reaction gas is controlled at 1–5000 sccm, the flow rate of the ammonia is controlled at 1–1000 sccm, the temperature is 100–600℃, and the pressure is 1–100 Torr.

[0016] Optionally, the second reactant gas is a mixture of SiH4, N2O, and hydrocarbon gases.

[0017] Optionally, the hydrocarbon gas may be any one of C3H6, C2H4, C2H2, C2H6, and C3H8.

[0018] Optionally, an etching pattern is formed on the sacrificial layer and the hard mask layer, including:

[0019] The hard mask layer is etched using dry etching to form an etching pattern;

[0020] The etched hard mask layer is used as a mask to etch the sacrificial layer, and the etched pattern is transferred to the sacrificial layer.

[0021] The patterning method provided by this invention improves the sacrificial layer and hard mask layer above the target layer to be etched. The pattern obtained after etching has basically vertical sidewalls, which is particularly suitable for etching processes with small dimensions and can obtain fine patterns on the target layer. Attached Figure Description

[0022] Figure 1 This is a schematic flowchart of a patterning method provided in an embodiment of the present invention;

[0023] Figure 2 A schematic diagram of a structure for forming an etching pattern using the patterning method provided in the embodiments of the present invention. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and not intended to limit the scope of this disclosure. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention. Furthermore, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessarily obscuring the concepts of this disclosure.

[0025] The accompanying drawings illustrate various structural schematics according to embodiments of the present disclosure. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0026] In the context of this disclosure, when a layer / element is referred to as being "above" another layer / element, the layer / element may be directly above the other layer / element, or there may be an intermediate layer / element between them. Additionally, if a layer / element is "above" another layer / element in one orientation, then when the orientation is reversed, the layer / element may be "below" the other layer / element.

[0027] Figure 1 This is a schematic flowchart illustrating a patterning method provided in an embodiment of the present invention. Figure 1 As shown, an embodiment of the present invention provides a patterning method, the method comprising:

[0028] Step 101: A sacrificial layer is formed on the target layer to be etched. The sacrificial layer is a low-density carbon thin film.

[0029] Step 102: Form a hard mask layer made of SiOCN on the sacrificial layer;

[0030] Step 103: Form an etching pattern on the sacrificial layer and the hard mask layer;

[0031] Step 104: Etch the target layer using the formed etching pattern.

[0032] In one implementation, step 101, the sacrificial layer can be formed using PECVD (plasma-enhanced chemical vapor deposition). Specifically, a first reaction gas containing carbon and hydrogen, along with an inert gas, is introduced into the reaction chamber. The gas flow rate is controlled at 10–5000 sccm, the temperature at 100–800°C, and the pressure at 1–100 Torr. The first reaction gas can be any one of C3H6, C2H4, C2H2, C2H6, and C3H8. The inert gas can be any one of argon (Ar), helium (He), and chlorine (Cl).

[0033] Further, in step 102, the hard mask layer can be formed using PECVD. Specifically, a second reaction gas containing silicon, oxygen, carbon, and nitrogen, as well as ammonia (NH3), is introduced into the reaction chamber. The flow rate of the second reaction gas is controlled at 1–5000 sccm, the flow rate of the ammonia is controlled at 1–1000 sccm, the temperature is 100–600°C, and the pressure is 1–100 Torr. The second reaction gas can be a mixture of SiH4, N2O, and hydrocarbon gases. The hydrocarbon gas can be any one of C3H6, C2H4, C2H2, C2H6, and C3H8.

[0034] Further, in step 103, an etching pattern is formed on the sacrificial layer and the hard mask layer, specifically including: etching the hard mask layer using dry etching to form an etching pattern; using the etched hard mask layer as a mask to etch the sacrificial layer, transferring the etching pattern to the sacrificial layer. Finally, the target layer to be etched is etched.

[0035] refer to Figure 2 , where 201 represents the target layer to be etched, 202 represents the low-density carbon film, and 203 represents the SiOCN film. Figure 2 The image shows the etched pattern formed after etching, with substantially vertical sidewalls.

[0036] The patterning method provided in this invention improves the sacrificial layer and hard mask layer above the target layer to be etched. The pattern obtained after etching has basically vertical sidewalls, which is particularly suitable for etching processes with small dimensions and can obtain fine patterns on the target layer.

[0037] It should also be noted that the sacrificial layer and hard mask layer can be formed in multiple layers, and alternating sacrificial layers and hard mask layers can be formed repeatedly as needed.

[0038] The above description does not provide detailed explanations of the technical aspects of each layer's patterning, etching, etc. However, those skilled in the art should understand that various technical means can be used to form layers and regions of the desired shape. Furthermore, to form the same structure, those skilled in the art can also design methods that are not entirely identical to those described above. Additionally, although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination.

[0039] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A patterning method, characterized in that, include: A sacrificial layer is formed on the target layer to be etched. The sacrificial layer is a low-density carbon film. The sacrificial layer is formed by PECVD, which includes: introducing a first reaction gas containing carbon and hydrogen elements and an inert gas into the reaction chamber. The gas flow rate is controlled at 10~5000 sccm, the temperature is 100~800℃, and the pressure is 1~100 Torr. The first reaction gas is any one of C3H6, C2H4, C2H2, C2H6 and C3H8, and the inert gas is argon or helium. A hard mask layer made of SiOCN is formed on the sacrificial layer; An etching pattern is formed on the sacrificial layer and the hard mask layer; The target layer is etched using the formed etching pattern.

2. The method according to claim 1, characterized in that, The hard mask layer is formed by PECVD and includes: A second reaction gas containing silicon, oxygen, carbon, and nitrogen, as well as ammonia, is introduced into the reaction chamber. The flow rate of the second reaction gas is controlled at 1~5000 sccm, the flow rate of the ammonia is controlled at 1~1000 sccm, the temperature is 100~600℃, and the pressure is 1~100 Torr.

3. The method according to claim 2, characterized in that, The second reacting gas is a mixture of SiH4, N2O and hydrocarbon gases.

4. The method according to claim 3, characterized in that, The hydrocarbon gas used is any one of C3H6, C2H4, C2H2, C2H6 and C3H8.

5. The method according to claim 1, characterized in that, Forming etching patterns on the sacrificial layer and the hard mask layer includes: The hard mask layer is etched using dry etching to form an etching pattern; The etched hard mask layer is used as a mask to etch the sacrificial layer, and the etched pattern is transferred to the sacrificial layer.

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