Formation method of semiconductor device
By forming a silicon oxynitride material layer on the surface of the polycrystalline silicon material layer to cover and protect its surface, the problem of particles formed by gasification of polycrystalline silicon in the annealing process is solved, and the quality and reliability of semiconductor devices are improved.
Patent Information
- Application Number
- CN202510397008.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-31
- Publication Date
- 2025-07-04
AI Technical Summary
In the annealing process of semiconductor devices, the polysilicon material layer sublimates at high temperature to form gaseous polysilicon, resulting in particle deposition, affecting device quality, and uneven oxygen oxidation may lead to the risk of polysilicon bridging.
The silicon oxynitride material layer is formed on the surface of the polycrystalline silicon material layer covering its surface, side walls and gate oxide layer surface exposed in the opening. After the annealing process, the silicon oxynitride material layer is removed to prevent the polycrystalline silicon from gasifying to form particles.
It effectively reduces the formation of particles, improves the quality of semiconductor devices, avoids the risk of polysilicon bridging, and improves the overall performance of the device.
Smart Images
Figure CN120264832A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of semiconductor technology, and in particular to a method for forming a semiconductor device. Background Art
[0002] Polycrystalline silicon layers are often used in semiconductor devices. For example, in some BCD devices, it is necessary to form and etch polycrystalline silicon layers. The shapes of the polycrystalline silicon layers to be formed in different regions are also different. For example, in some regions, a gate oxide layer needs to be formed on a substrate, then a polycrystalline silicon material layer is formed on the surface of the gate oxide layer, and then the polycrystalline silicon material layer is etched to form a polycrystalline silicon material layer with an opening, and a part of the surface of the gate oxide layer is exposed inside the opening. Then, an annealing process is performed on the polycrystalline silicon material layer to improve the quality of the polycrystalline silicon material layer. The specific method for forming a semiconductor device is as follows. First, please refer to Figure 1 , a substrate 101 is provided. The substrate 101 mostly selects silicon material, for example, a wafer can be selected as the substrate 101. Then, a gate oxide layer 102 is formed on the surface of the substrate 101, and the forming method can be a method of depositing a layer of silicon dioxide. Then, a polycrystalline silicon material layer 103 is formed on the surface of the gate oxide layer 102, and the forming method can be a method of depositing polycrystalline silicon material. Then, the polycrystalline silicon material layer 103 is etched according to the region where it is located to form the required shape. For example, please refer to Figure 2 , the polycrystalline silicon material layer 103 is etched to form an opening 104, and a part of the surface of the gate oxide layer 102 is exposed in the opening 104. Then, an annealing process is performed on the polycrystalline silicon material layer 103 after the opening 104 has been etched.
[0003] The annealing process of the prior art is as follows: the semiconductor device is placed in the chamber of the annealing process. First, the temperature is raised from about 25°C to about 300°C for preheating, and then annealing treatment is performed at a temperature of about 1100°C for about 30 s. Finally, the temperature is lowered to about 550°C for cooling.
[0004] However, the polycrystalline silicon in the polycrystalline silicon material layer 103 sublimes to form gaseous polycrystalline silicon in the nitrogen (N2) atmosphere at a high temperature of 1100°C in the annealing machine. When the temperature in the chamber drops or is at room temperature, the gaseous polycrystalline silicon condenses to form particles 105 (particles) and drops. The dropped particles 105 have a very great impact on the quality of the polycrystalline silicon material layer 103, and further reduce the quality of the subsequent formed semiconductor device. Although some processes solve the problem of particles by introducing a small amount of oxygen into the chamber of the annealing process, if there are problems with the environment or the machine being unstable, it will cause the silicon dioxide formed on the surface of the polycrystalline silicon material layer 103 to be unevenly oxidized by oxygen, and there will be a risk of polycrystalline silicon bridging in the region where the distance between adjacent polycrystalline silicon material layers 103 is small. Summary of the Invention
[0005] An object of the present invention is to provide a method for forming a semiconductor device, which can reduce the formation of particles, thereby improving the quality of the semiconductor device.
[0006] To achieve the above object, the present invention provides a method for forming a semiconductor device, comprising:
[0007] Providing a substrate;
[0008] Successively forming a gate oxide layer and a polysilicon material layer having an opening on the surface of the substrate, and a part of the surface of the gate oxide layer is exposed in the opening;
[0009] Forming a silicon oxynitride material layer on the surface of the polysilicon material layer, and the silicon oxynitride material layer covers the surface of the polysilicon material layer, the sidewalls of the opening, and the surface of the gate oxide layer exposed in the opening;
[0010] Performing an annealing process on the polysilicon material layer and the silicon oxynitride material layer;
[0011] Removing the silicon oxynitride material layer.
[0012] Optionally, in the method for forming a semiconductor device, the method for forming a gate oxide layer on the surface of the substrate includes: depositing an oxide layer on the surface of the substrate to form a gate oxide layer.
[0013] Optionally, in the method for forming a semiconductor device, the method for forming a polysilicon material layer having an opening on the surface of the gate oxide layer includes:
[0014] Forming a layer of polysilicon material layer on the surface of the gate oxide layer;
[0015] Etching the polysilicon material layer to form an opening.
[0016] Optionally, in the method for forming a semiconductor device, the thickness of the silicon oxynitride layer is 180 Å to 220 Å.
[0017] Optionally, in the method for forming a semiconductor device, the temperature of the annealing process is greater than 300 °C.
[0018] Optionally, in the method for forming a semiconductor device, the time of the annealing process is greater than 30 s.
[0019] Optionally, in the method for forming a semiconductor device, the silicon oxynitride material layer is removed by wet etching.
[0020] Optionally, in the method for forming a semiconductor device, the silicon oxynitride material layer is removed by wet etching with phosphoric acid.
[0021] Optionally, in the method for forming the semiconductor device, the rate of removing the silicon oxynitride material layer by wet etching with phosphoric acid is 20 Å / min to 30 Å / min.
[0022] Optionally, in the method for forming the semiconductor device, the temperature of the phosphoric acid is 150°C to 180°C.
[0023] In the method for forming a semiconductor device provided by the present invention, it includes: providing a substrate, sequentially forming a gate oxide layer and a polysilicon material layer with an opening on the surface of the substrate, and a part of the surface of the gate oxide layer is exposed inside the opening; forming a silicon oxynitride material layer on the surface of the polysilicon material layer, and the silicon oxynitride material layer covers the surface of the polysilicon material layer, the side walls of the opening, and the surface of the gate oxide layer exposed inside the opening; performing an annealing process on the polysilicon material layer and the silicon oxynitride material layer; removing the silicon oxynitride material layer. In the present invention, after etching the polysilicon material layer to form an opening, a layer of silicon oxynitride material layer is formed, and the silicon oxynitride material layer covers the surface of the polysilicon material layer, the side walls of the opening, and the surface of the gate oxide layer exposed inside the opening. The silicon oxynitride material layer covers and protects all the places where the polysilicon material layer can be exposed. When performing the annealing process, it prevents the polysilicon material layer from generating polysilicon gas, thereby preventing the polysilicon gas from pre-cooling to form particulate impurities. Finally, the present invention adopts the method of forming a silicon oxynitride material layer to cover the surface of the polysilicon material layer, the side walls of the opening, and the surface of the gate oxide layer exposed inside the opening, reducing the formation of particles and improving the quality of the semiconductor device. Description of the Drawings
[0024] Figure 1 is a schematic structural diagram of a semiconductor device after forming a polysilicon material layer in the prior art;
[0025] Figure 2 is a schematic structural diagram of a semiconductor device after etching the polysilicon material layer to form an opening in the prior art;
[0026] Figure 3 is a schematic structural diagram of a semiconductor device after performing an annealing process in the prior art;
[0027] Figure 4 is a flowchart of the method for forming a semiconductor device according to an embodiment of the present invention;
[0028] Figure 5 is a schematic structural diagram of a semiconductor device after forming a polysilicon material layer according to an embodiment of the present invention;
[0029] Figure 6 is a schematic structural diagram of a semiconductor device after etching the polysilicon material layer to form an opening according to an embodiment of the present invention;
[0030] Figure 7 It is a schematic structural diagram of a semiconductor device after forming a silicon oxynitride material layer according to an embodiment of the present invention;
[0031] Figure 8 It is a schematic structural diagram of a semiconductor device after removing the silicon oxynitride material layer according to an embodiment of the present invention;
[0032] In the figure: 101 - substrate, 102 - gate oxide layer, 103 - polysilicon material layer, 104 - opening, 105 - particle, 201 - substrate, 202 - gate oxide layer, 203 - polysilicon material layer, 204 - opening, 205 - silicon oxynitride material layer. Specific embodiments
[0033] The following will describe the specific embodiments of the present invention in more detail with reference to the schematic diagrams. According to the following description, the advantages and features of the present invention will be clearer. It should be noted that the drawings are all in a very simplified form and use non-precise scales, only for the purpose of facilitating and clearly assisting in explaining the purpose of the embodiments of the present invention.
[0034] In the following text, terms such as "first" and "second" are used to distinguish between similar elements and are not necessarily used to describe a specific order or time sequence. It is to be understood that, where appropriate, these terms may be replaced. Similarly, if the methods described herein include a series of steps, and the order of these steps presented herein is not necessarily the only order in which these steps can be performed, and some of the described steps may be omitted and / or some other steps not described herein may be added to the method.
[0035] Moreover, it should be understood that when a layer (or film), region, pattern or structure is referred to as being "on" a substrate, layer (or film), region and / or pattern, it can be directly on another layer or substrate, and / or there may also be an intervening layer. Additionally, it should be understood that when a layer is referred to as being "under" another layer, it can be directly under another layer, and / or there may also be one or more intervening layers. Additionally, the references to "on" and "under" each layer can be based on the drawings.
[0036] Please refer to Figure 4 , Figure 4 which is a flowchart of a method for forming a semiconductor device according to an embodiment of the present invention. The present invention provides a method for forming a semiconductor device, including:
[0037] S11: Provide a substrate, and sequentially form a gate oxide layer and a polysilicon material layer with an opening on the surface of the substrate, and a part of the surface of the gate oxide layer is exposed in the opening;
[0038] S12: Form a silicon oxynitride material layer on the surface of the polysilicon material layer, where the silicon oxynitride material layer covers the surface of the polysilicon material layer, the sidewalls of the opening, and the surface of the gate oxide layer exposed within the opening;
[0039] S13: Perform an annealing process on the polysilicon material layer and the silicon oxynitride material layer;
[0040] S14: Remove the silicon oxynitride material layer.
[0041] For the specific formation method, please refer to Figure 5 , First, provide a substrate 201. In the embodiment of the present invention, a silicon material is selected as the substrate, such as a wafer. Next, form a gate oxide layer 202 on the surface of the substrate 201 for isolating the substrate 201 from other structures in the subsequent process. The material of the gate oxide layer 202 can be an oxide layer, such as silicon dioxide. In the embodiment of the present invention, silicon dioxide is selected as the material of the gate oxide layer 202, and in other embodiments of the present invention, it can also be other oxides. The method for forming the gate oxide layer 202 can be a low-pressure chemical vapor deposition method, such as using a low-pressure chemical vapor deposition method. Next, form a polysilicon material layer 203 on the surface of the gate oxide layer 202, and the polysilicon material layer 203 can be formed by a chemical vapor deposition polysilicon method.
[0042] Next, please refer to Figure 6 , Etch the polysilicon material layer 203 to form an opening 204, thereby dividing the polysilicon material layer 203 into several parts, and each part is used to form the gate structure of different devices. The specific method for etching the polysilicon material layer 203 can be to first form a photoresist layer on the surface of the polysilicon material layer 203, and then develop and etch the photoresist layer to form a patterned photoresist layer. The patterned photoresist layer defines the area of the opening to be etched. Next, use the patterned photoresist layer as a mask to etch the polysilicon material layer 203 to form an opening 204 within the polysilicon material layer 203, and the opening 204 exposes a part of the surface of the gate oxide layer 202.
[0043] Next, please refer to Figure 7, a silicon oxynitride material layer 205 is formed on the surface of the polysilicon material layer 203, and the forming method can be a method of depositing a silicon oxynitride material. The silicon oxynitride material layer 205 covers the polysilicon material layer 203, the sidewalls of the opening 204, and the surface of the gate oxide layer 202 exposed in the opening 204, that is, the silicon oxynitride material layer 205 completely covers and protects the exposed part of the polysilicon material layer 203. The thickness of the formed silicon oxynitride material layer 205 can be 180 Å to 220 Å, preferably 200 Å. Then, the entire semiconductor device is placed in an annealing process chamber, and nitrogen is introduced to perform an annealing process on the polysilicon material layer 203. The annealing temperature can be greater than 300 °C, and the annealing time can be greater than 30 s. In the annealing process, since the silicon oxynitride material layer 205 completely covers and protects the exposed part of the polysilicon material layer 203. Therefore, the polysilicon material layer 203 will not sublime to form gaseous polysilicon, and when the temperature in the chamber drops or at room temperature, no particles will be formed and fall off.
[0044] Next, please refer to Figure 7 and Figure 8 , the silicon oxynitride material layer 205 is removed to expose the surface of the polysilicon material layer 203, the sidewalls of the opening, and the surface of the gate oxide layer 202 in the opening, so as to obtain a high-quality polysilicon material layer 203 without particles. Subsequently, the required device can be formed on the polysilicon material layer 203. In the embodiment of the present invention, a wet etching method can be used to remove the silicon oxynitride material layer 205. Specifically, phosphoric acid wet etching can be used to remove the silicon oxynitride material layer 205. The temperature of the phosphoric acid can be 150 °C to 180 °C. The etching rate of using phosphoric acid wet etching to remove the silicon oxynitride material layer is 20 Å / min to 30 Å / min, so the silicon oxynitride material layer 205 can be removed after about 2 minutes. The etching rate of phosphoric acid for removing silicon dioxide is about 1.3 Å / min, and the etching rate of phosphoric acid for removing polysilicon is about 2 Å / min. Therefore, when the silicon oxynitride material layer 205 is removed by phosphoric acid, the gate oxide layer 202 and the polysilicon material layer 203 are hardly reduced.
[0045] In summary, in the method for forming a semiconductor device provided by the embodiments of the present invention, the method includes: providing a substrate, sequentially forming a gate oxide layer and a polysilicon material layer with an opening on the surface of the substrate, and exposing a part of the surface of the gate oxide layer within the opening; forming a silicon oxynitride material layer on the surface of the polysilicon material layer, the silicon oxynitride material layer covering the surface of the polysilicon material layer, the sidewalls of the opening, and the surface of the gate oxide layer exposed within the opening; performing an annealing process on the polysilicon material layer and the silicon oxynitride material layer; and removing the silicon oxynitride material layer. In the present invention, after etching the polysilicon material layer to form an opening, a layer of silicon oxynitride material layer is formed, and the silicon oxynitride material layer covers the surface of the polysilicon material layer, the sidewalls of the opening, and the surface of the gate oxide layer exposed within the opening. The silicon oxynitride material layer covers and protects all the places where the polysilicon material layer can be exposed. During the annealing process, it prevents the polysilicon material layer from generating polysilicon gas, thereby preventing the polysilicon gas from pre-cooling to form particulate impurities. Finally, the present invention adopts the method of forming a silicon oxynitride material layer to cover the surface of the polysilicon material layer, the sidewalls of the opening, and the surface of the gate oxide layer exposed within the opening, reducing the formation of particles and improving the quality of the semiconductor device.
[0046] The above are only the preferred embodiments of the present invention and do not impose any limitation on the present invention. Any person skilled in the art within the technical field, without departing from the scope of the technical solution of the present invention, makes any form of equivalent substitution or modification and other changes to the technical solution and technical content disclosed by the present invention, all of which belong to the content of the technical solution not departing from the present invention and still fall within the protection scope of the present invention.
Claims
1. A method for forming a semiconductor device, characterized in that, Including: Providing a substrate; Successively forming a gate oxide layer and a polysilicon material layer with an opening on the surface of the substrate, and a part of the surface of the gate oxide layer is exposed within the opening; Forming a silicon oxynitride material layer on the surface of the polysilicon material layer, and the silicon oxynitride material layer covers the surface of the polysilicon material layer, the sidewalls of the opening, and the surface of the gate oxide layer exposed within the opening; Performing an annealing process on the polysilicon material layer and the silicon oxynitride material layer; Removing the silicon oxynitride material layer.
2. The method for forming a semiconductor device according to claim 1, wherein, The method for forming a gate oxide layer on the surface of the substrate includes: depositing an oxide layer on the surface of the substrate to form a gate oxide layer.
3. The method for forming a semiconductor device according to claim 1, wherein, The method for forming a polysilicon material layer with an opening on the surface of the gate oxide layer includes: Forming a layer of polysilicon material on the surface of the gate oxide layer; Etching the polysilicon material layer to form an opening.
4. The method for forming a semiconductor device according to claim 1, wherein, The thickness of the silicon oxynitride layer is 180 Å to 220 Å.
5. The method for forming a semiconductor device according to claim 1, wherein The temperature of the annealing process is greater than 300 °C.
6. The method for forming a semiconductor device according to claim 1, wherein, The time of the annealing process is greater than 30 s.
7. The method for forming a semiconductor device according to claim 1, wherein Wet etching is used to remove the silicon oxynitride material layer.
8. The method for forming a semiconductor device according to claim 7, wherein, Phosphoric acid is used for wet etching to remove the silicon oxynitride material layer.
9. The method for forming a semiconductor device according to claim 8, wherein, The etching rate of using phosphoric acid for wet etching to remove the silicon oxynitride material layer is 20 Å / min to 30 Å / min.
10. The method for forming a semiconductor device according to claim 8, wherein, The temperature of the phosphoric acid is 150 °C to 180 °C.