Method of fabricating thin films and semiconductor structures

Abstract

The application provides a thin film and a semiconductor structure manufacturing method, and the thin film manufacturing method comprises the following steps: providing a substrate, pretreating the substrate, changing chemical bonds on the surface of the substrate which have inhibitory effect on thin film deposition, and forming a thin film on the substrate. The application first pretreats the substrate, changes the chemical bonds on the surface of the substrate which have inhibitory effect on thin film deposition, and then forms a thin film on the substrate, so that the deposition rate of the thin film can be improved, the manufacturing cost of the thin film is reduced, and the production per hour of the wafer is improved.

Description

Technical Field

[0001] This invention relates to the field of semiconductor integrated circuit technology, and in particular to a method for fabricating a thin film and a method for fabricating a semiconductor structure. Background Technology

[0002] Plasma Enhanced Atomic Layer Deposition (PEALD) is widely used in chip fabrication due to its excellent filling performance and high-quality thin film properties. Some processes involve forming silicon nitride on oxide layers using PEALD, such as forming a pre-metal dielectric (PMD) layer as an etch stop layer, or forming silicon nitride on vias as a capping layer.

[0003] While plasma atomic layer deposition (PAL) for silicon nitride formation offers excellent filling performance, its low deposition rate results in a lengthy production time and high costs. Therefore, improving the silicon nitride deposition rate to reduce costs and increase wafer per hour (WPH) is a crucial issue that needs to be addressed. Summary of the Invention

[0004] The purpose of this invention is to provide a thin film and semiconductor structure and a method for fabricating the same, which improves the deposition rate of the thin film, saves manufacturing costs, and increases the hourly output of wafers.

[0005] To solve the above-mentioned technical problems, according to a first aspect of the present invention, a method for manufacturing a thin film is provided, comprising the following steps:

[0006] Provide a substrate, pretreat the substrate to alter the chemical bonds on the substrate surface that inhibit thin film deposition; and

[0007] A thin film is formed on the substrate.

[0008] Optionally, altering the chemical bonds on the substrate surface that inhibit thin film deposition includes: converting the Si-H bonds on the substrate surface into Si-OH bonds, or converting the Si-OH bonds on the substrate surface into Si-H bonds.

[0009] Optionally, the thin film comprises a silicon nitride thin film, and the pretreatment includes converting Si-OH bonds on the substrate surface into Si-H bonds.

[0010] Optionally, the pretreatment includes pre-cleaning the substrate with a cleaning agent containing hydrogen ions.

[0011] Optional cleaning agents containing hydrogen ions include DHF or SPM.

[0012] Optionally, before pretreating the substrate, the fabrication method further includes forming a silicon oxide layer on the substrate.

[0013] Optionally, a thin film may be formed on the substrate using a plasma-enhanced chemical vapor deposition process, a low-pressure chemical vapor deposition process, a plasma-enhanced atomic layer deposition process, or a thermal atomic layer deposition process.

[0014] Optionally, the step of forming a thin film on the substrate includes:

[0015] The substrate is placed inside the reaction chamber;

[0016] A precursor gas is introduced into the reaction chamber, and the precursor gas is adsorbed onto the surface of the substrate. The adsorption efficiency of the substrate for the precursor gas after the chemical bond change is higher than that of the substrate before the chemical bond change.

[0017] A reaction gas is introduced into the reaction chamber, and the reaction gas is ionized to form plasma, which reacts with the precursor gas to form a thin film.

[0018] Optionally, the precursor gas includes P41, and the reactant gas includes nitrogen.

[0019] To address the aforementioned technical problems, according to a second aspect of the present invention, a method for fabricating a semiconductor structure is also provided, comprising the following steps:

[0020] A substrate is provided, on which a stacked structure comprising at least an oxide layer, a nitride layer and an oxide layer is formed;

[0021] The stacked structure is etched to form trenches that expose the substrate;

[0022] Pretreatment is performed to alter the chemical bonds on the trench sidewalls, bottom, and surface of the stacked structure that inhibit thin film deposition; and

[0023] A thin film is formed, which covers the sidewalls and bottom of the trench and the stacked structure.

[0024] In the thin film fabrication method provided by the present invention, the substrate is first pretreated to change the chemical bonds on the substrate surface that inhibit the deposition of the thin film, and then the thin film is formed on the substrate. This can improve the deposition rate of the thin film, thereby reducing the fabrication cost of the thin film and increasing the hourly output of wafers.

[0025] Furthermore, by pretreating the substrate, the chemical bonds on the substrate surface that inhibit film deposition are altered. The substrate with altered chemical bonds exhibits higher adsorption efficiency for precursor gases than the substrate without altered chemical bonds. In other words, the adsorption of precursor gases is enhanced by altering chemical bonds, thereby increasing the film deposition rate.

[0026] The semiconductor structure fabrication method provided by this invention first provides a substrate, on which a stacked structure comprising at least an oxide layer, a nitride layer, and an oxide layer is formed. Next, the stacked structure is etched to form trenches exposing the substrate. Then, a pretreatment is performed to alter the chemical bonds on the trench sidewalls, bottom, and the exposed substrate surface that inhibit thin film deposition. Finally, a thin film is formed, covering the trench sidewalls, bottom, and the substrate surface. This invention performs pretreatment before thin film formation to alter the chemical bonds on the substrate and trench surface, thereby increasing the thin film deposition rate, reducing fabrication costs, and improving the efficiency of semiconductor structure fabrication. Attached Figure Description

[0027] Figures 1a to 1d This is a schematic diagram of the steps involved in forming a thin film on a substrate using plasma-enhanced atomic layer deposition (PEALD).

[0028] Figures 2a to 2d This is a schematic diagram of the steps involved in the chemisorption of P41 on a silicon substrate.

[0029] Figures 3a to 3f This is a schematic diagram of the steps involved in the chemisorption of P41 on a silicon oxide layer.

[0030] Figure 4 This is a schematic flowchart of a method for manufacturing a thin film according to an embodiment of the present invention.

[0031] Figure 5 This is a schematic flowchart of a method for fabricating a semiconductor structure according to an embodiment of the present invention.

[0032] Figures 6 to 8 This is a schematic diagram of the steps in a method for fabricating a semiconductor structure according to an embodiment of the present invention.

[0033] Figures 9a to 9d This is a schematic diagram of different groups of semiconductor structures provided in an embodiment of the present invention.

[0034] Explanation of reference numerals in the attached figures:

[0035] 10-Substrate; 20-Layered structure; 21-First oxide layer; 22-First nitride layer; 23-Second oxide layer; 24-Second nitride layer; 25-Third oxide layer; 31-Trench; 32-Thin film. Detailed Implementation

[0036] Figures 1a to 1d This is a schematic diagram illustrating the steps involved in forming a thin film on a substrate using plasma-enhanced atomic layer deposition (PEALD). The steps for forming a thin film on a substrate using PEALD generally include: First, please refer to... Figure 1a As shown, the substrate is placed in the reaction chamber, and a precursor gas is introduced into the reaction chamber, where the precursor gas is adsorbed onto the substrate surface; then, please refer to... Figure 1b As shown, remove excess precursor gas, for example, by blowing away excess precursor gas; then, please refer to... Figure 1c and Figure 1d As shown, a reactive gas is introduced into the reaction chamber, and the reactive gas is ionized to form plasma. The plasma reacts with the precursor gas on the substrate surface to form a thin film. Afterward, unreacted gas and reaction byproducts are removed, for example, by blowing away the byproducts and excess gas.

[0037] When the formed thin film is a silicon nitride thin film and the substrate is a silicon substrate, the precursor gas contains P41 (SiH2I2) and the reactant gas contains nitrogen.

[0038] Figures 2a to 2d This is a schematic diagram illustrating the steps involved in the chemisorption of P41 on a silicon substrate. Please refer to it. Figures 2a to 2d As shown, silicon-hydrogen bonds (Si-H) are formed on the silicon (Si) substrate. After P41 is introduced, the I (iodine) in P41 combines with the H (hydrogen) in the silicon substrate to form HI (hydrogen iodide) gas. The Si (silicon) in P41 combines with the Si (silicon) in the silicon substrate, so that P41 is adsorbed on the silicon substrate.

[0039] Figures 3a to 3f This is a schematic diagram illustrating the steps of chemisorption of P41 on a silicon oxide (SiOx) layer. Please refer to it. Figures 3a to 3f As shown, the silicon oxide layer forms silicon-hydroxyl (Si-OH) bonds. After P41 is introduced, the I (iodine) in P41 combines with the H (hydrogen) in the silicon substrate to form HI (hydrogen iodide) gas, and the Si (silicon) in P41 combines with the O (oxygen) in the silicon substrate, causing P41 to be adsorbed onto the silicon oxide layer. However, please refer to... Figure 3d As shown, before I combines with H to form HI gas, there is a transition state between I, H, Si and O.

[0040] Through analysis, the inventors discovered that the adsorption efficiency of P41 is related to surface chemical bonds. Si-H bonds are conducive to the adsorption of P41, while Si-OH bonds are prone to forming unstable transition states during the adsorption process, which is not conducive to the adsorption of P41. In other words, Si-OH bonds have an inhibitory effect on the adsorption of P41, resulting in the substrate surface having an inhibitory effect on thin film deposition.

[0041] Further research has led to the present invention providing a method for fabricating a thin film, comprising: providing a substrate, pretreating the substrate to alter chemical bonds on the substrate surface that inhibit thin film deposition, and forming a thin film on the substrate.

[0042] Accordingly, the present invention also provides a method for fabricating a semiconductor structure, comprising: providing a substrate, forming a stacked structure comprising at least an oxide layer, a nitride layer and an oxide layer on the substrate; etching the stacked structure to form trenches exposing the substrate; performing pretreatment to alter chemical bonds in the trench sidewalls, bottom and exposed substrate surface that inhibit thin film deposition; and forming a thin film covering the trench sidewalls, bottom and the surface of the substrate.

[0043] In the thin film fabrication method provided by the present invention, the substrate is first pretreated to change the chemical bonds on the substrate surface that inhibit the deposition of the thin film, and then the thin film is formed on the substrate. This can improve the deposition rate of the thin film, thereby reducing the fabrication cost of the thin film and increasing the hourly output of wafers.

[0044] In the semiconductor structure fabrication method provided by the present invention, a pretreatment is performed before the thin film is formed to change the chemical bonds on the substrate surface to which the thin film is to be formed, thereby increasing the deposition rate of the thin film, reducing the fabrication cost of the thin film, and improving the fabrication efficiency of the semiconductor structure.

[0045] 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.

[0046] As used herein, the singular forms “a,” “an,” and “the” include plural objects unless otherwise expressly indicated. As used herein, the term “or” is generally used to mean “and / or” unless otherwise expressly indicated. As used herein, the term “a number” is generally used to mean “at least one” unless otherwise expressly indicated. As used herein, the term “at least two” is generally used to mean “two or more” unless otherwise expressly indicated. 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.

[0047] Figure 4 This is a schematic flowchart of a method for fabricating a thin film according to an embodiment of the present invention. Figure 4 As shown, the method for fabricating the thin film in this embodiment includes the following steps:

[0048] S11: Providing a substrate, pretreating the substrate to alter the chemical bonds on the substrate surface that inhibit thin film deposition; and

[0049] S12: A thin film is formed on the substrate.

[0050] In step S11, a substrate is provided and pretreated to alter the chemical bonds on the substrate surface that inhibit thin film deposition.

[0051] The substrate material can be silicon, germanium, silicon germanide, silicon carbide, gallium arsenide, or indium gallium arsenide, or it can be silicon-on-insulator or germanium-on-insulator; or it can be other materials, such as gallium arsenide or other III-V compounds. In this embodiment, the substrate is a silicon substrate.

[0052] The substrate is pretreated to alter the chemical bonds on its surface that inhibit thin film deposition. In one embodiment of the invention, altering the chemical bonds on the substrate surface that inhibit thin film deposition includes: converting Si-H bonds on the substrate surface into Si-OH bonds, or converting Si-OH bonds on the substrate surface into Si-H bonds. That is, if the chemical bonds on the substrate surface are Si-H bonds, and Si-H bonds inhibit subsequent thin film deposition, then the substrate is pretreated to convert the Si-H bonds into Si-OH bonds; if the chemical bonds on the substrate surface are Si-OH bonds, and Si-OH bonds inhibit subsequent thin film deposition, then the substrate is pretreated to convert the Si-OH bonds into Si-H bonds. Of course, this is not limited to Si-OH and Si-H bonds; the substrate surface may also have other chemical bonds that inhibit thin film deposition, and these chemical bonds can all be altered.

[0053] Before pretreatment of the substrate, the substrate can be cleaned to remove impurities and contaminants from the substrate surface, such as by wet cleaning or deionized water cleaning.

[0054] Before pretreating the substrate, a silicon oxide layer may be formed on the substrate. In one embodiment, the oxide layer may be formed using plasma-enhanced atomic layer deposition (PEALD) or plasma-enhanced chemical vapor deposition (PECVD), but this is not the only option.

[0055] In one embodiment of the present invention, the thin film is a silicon nitride thin film, and the pretreatment includes converting the Si-OH bonds on the substrate surface into Si-H bonds. That is, when a silicon nitride thin film is formed on the substrate, the Si-OH bonds on the substrate surface (when a silicon oxide layer is formed on the substrate) have an inhibitory effect on the deposition of the silicon nitride thin film. In the pretreatment, the Si-OH bonds on the substrate surface are converted into Si-H bonds to improve the deposition rate of the silicon nitride thin film.

[0056] The pretreatment includes pre-cleaning the substrate with a cleaning agent containing hydrogen ions (H+) to convert the Si-OH bonds on the substrate surface into Si-H bonds. In one embodiment, the cleaning agent containing hydrogen ions includes DHF (diluted hydrofluoric acid) or SPM (a mixture of sulfuric acid and hydrogen peroxide).

[0057] In step S12, a thin film is formed on the substrate.

[0058] In one embodiment of the present invention, a thin film may be formed on the substrate using plasma-enhanced chemical vapor deposition (PECVD), low-pressure chemical vapor deposition (LPCVD), plasma-enhanced atomic layer deposition (PECVD), thermal atomic layer deposition (thermal ALD), or any other suitable method known to those skilled in the art.

[0059] The following explanation uses the formation of a thin film on the substrate using a plasma-enhanced atomic layer deposition process as an example.

[0060] First, the substrate is placed in the reaction chamber, that is, the substrate to be formed into a thin film and pretreated is placed in the reaction chamber.

[0061] Next, a precursor gas is introduced into the reaction chamber. The precursor gas is adsorbed onto the substrate surface. The adsorption efficiency of the substrate for the precursor gas after the chemical bond change is higher than that of the substrate before the chemical bond change. In this embodiment, the precursor gas is introduced into the reaction chamber and adsorbed onto the substrate surface until saturation, forming a layer to be reacted on the substrate surface.

[0062] For example, the precursor gas includes P41. Since the Si-OH bonds on the substrate surface have been converted into Si-H bonds, the substrate with Si-H bonds on its surface has a higher adsorption efficiency for the precursor gas than the substrate with Si-OH bonds on its surface. That is, the pretreatment of the substrate in step S11 improves the adsorption efficiency of the precursor gas.

[0063] In one embodiment, after introducing the precursor gas into the reaction chamber, the process further includes removing excess precursor gas. For example, an inert gas (e.g., argon) is introduced into the reaction chamber to flush it and remove excess precursor gas that has not been adsorbed by the substrate surface.

[0064] Next, a reactive gas is introduced into the reaction chamber. The reactive gas is ionized to form plasma, which reacts with the precursor gas to form a thin film. For example, the reactive gas contains nitrogen. Under a high-frequency or DC electric field, the nitrogen is ionized to form nitrogen plasma, which reacts with the precursor gas on the substrate surface to form silicon nitride on the substrate. Because the adsorption efficiency of the precursor gas on the substrate surface is improved, the amount of precursor gas adsorbed on the substrate surface increases, thereby increasing the film deposition rate.

[0065] In one embodiment, after the film is formed, the process further includes removing unreacted gases and reaction byproducts. For example, an inert gas (e.g., argon) is introduced into the reaction chamber to flush the chamber and remove unreacted gases and reaction byproducts.

[0066] In the thin film fabrication method provided by the present invention, the substrate is first pretreated to change the chemical bonds on the substrate surface that inhibit the deposition of the thin film, and then the thin film is formed on the substrate. This can improve the deposition rate of the thin film, thereby reducing the fabrication cost of the thin film and increasing the hourly output of wafers.

[0067] Accordingly, the present invention also provides a method for fabricating a semiconductor structure. Figure 5 This is a schematic flowchart of a method for fabricating a semiconductor structure according to an embodiment of the present invention. Figure 5 As shown, the method for fabricating the semiconductor structure in this embodiment includes the following steps:

[0068] S21: Provide a substrate, and form a stacked structure on the substrate comprising at least an oxide layer, a nitride layer and an oxide layer;

[0069] S22: Etch the stacked structure to form trenches that expose the substrate;

[0070] S23: Perform pretreatment to alter the chemical bonds on the trench sidewalls, bottom, and exposed substrate surface that inhibit thin film deposition; and

[0071] S24: Form a thin film that covers the sidewalls, bottom, and surface of the substrate of the trench.

[0072] Figures 6 to 8 This is a schematic diagram of the steps involved in fabricating a semiconductor structure according to an embodiment of the present invention. Next, we will combine... Figure 5 , Figures 6 to 8 The method for fabricating the semiconductor structure provided in the embodiments of the present invention will be described in detail.

[0073] In step S21, please refer to Figure 6 As shown, a substrate 10 is provided, and a stacked structure 20 comprising at least an oxide layer, a nitride layer and an oxide layer is formed on the substrate 10.

[0074] The substrate 10 can be made of silicon, germanium, silicon germanide, silicon carbide, gallium arsenide, or indium gallium arsenide, or it can be silicon-on-insulator or germanium-on-insulator; or it can be other materials, such as gallium arsenide or other III-V compounds. In this embodiment, the substrate 10 is a silicon substrate.

[0075] A multilayer structure 20 comprising at least an oxide layer, a nitride layer, and an oxide layer is formed on the substrate 10. In one embodiment of the present invention, please refer to... Figure 6 As shown, a first oxide layer 21, a first nitride layer 22, a second oxide layer 23, a second nitride layer 24, and a third oxide layer 25 are sequentially formed on the substrate 10. These layers constitute a stacked structure 20. Alternatively, in another embodiment of the invention, only the first oxide layer 21, the first nitride layer 22, and the second oxide layer 23 may be formed on the substrate 10. Furthermore, in another embodiment, more layers may be formed on the third oxide layer 25. It should be noted that the top layer of the stacked structure 20 is an oxide layer.

[0076] In one embodiment, the oxide layer is a silicon oxide layer and the nitride layer is a silicon nitride layer. The first oxide layer 21 can be formed using plasma-enhanced atomic layer deposition (PEALD), the first nitride layer 22 can be formed on the first oxide layer 21 using thermal atomic layer deposition (TEALD), the second oxide layer 23 can be formed on the first nitride layer 22 using plasma-enhanced chemical vapor deposition (PECVD), the second nitride layer 24 can be formed on the second oxide layer 23 using PECVD, and the third oxide layer 25 can be formed on the second nitride layer 24 using PECVD. However, this is not the only option; any other suitable method known to those skilled in the art can be used to form the oxide and nitride layers.

[0077] In one embodiment, the thicknesses of the third oxide layer 25 and the second oxide layer 23 are both greater than the thicknesses of the second nitride layer 24 and the first nitride layer 22. After the trenches are formed, the surface of the oxide layer is primarily exposed, thus allowing for pretreatment mainly of the oxide layer surface. For example, the thickness of the first oxide layer 21 is... The thickness of the first nitride layer 22 is The thickness of the second oxide layer 23 is The thickness of the second nitride layer 24 is The thickness of the third oxide layer 25 is Of course, this is not the only option; the specific thickness of each oxide and nitriding layer can be determined based on actual needs.

[0078] In step S22, please refer to Figure 7 As shown, the stacked structure 20 is etched to form trenches 31 that expose the substrate 10.

[0079] For example, firstly, a photoresist layer is formed on the stacked structure 20. The photoresist layer is exposed and developed to form a patterned photoresist layer, which exposes the area where a trench is to be formed. Next, the stacked structure 20 is etched using the patterned photoresist layer as a mask, i.e., the third oxide layer 25, the second nitride layer 24, the second oxide layer 23, the first nitride layer 22, and the first oxide layer 21 are etched sequentially until the substrate 10 is exposed, forming a trench 31 that penetrates the stacked structure 20 and exposes the substrate 10. Then, the patterned photoresist layer is removed.

[0080] In step S23, please continue to refer to Figure 7 As shown, pretreatment is performed to change the chemical bonds on the sidewalls and bottom of the trench 31 and the surface of the stacked structure 20 that inhibit thin film deposition.

[0081] For example, a cleaning agent containing hydrogen ions (H+) is used to pre-clean the sidewalls and bottom of the trench 31 and the stacked structure 20, that is, to clean the structure formed in step S22 above, so that the Si-OH bonds on the sidewalls and bottom of the trench 31 and the surface of the stacked structure 20 (specifically the surface of the third oxide layer 25) are converted into Si-H bonds. In one embodiment, DHF or SPM is used for cleaning.

[0082] In step S24, please refer to Figure 8 As shown, a thin film 32 is formed, which covers the sidewalls and bottom of the trench 31 and the laminated structure 20.

[0083] In one embodiment, the thin film 32 can be formed using a plasma-enhanced atomic layer deposition process. Of course, the thin film 32 can also be formed using any suitable process known to those skilled in the art, such as plasma-enhanced chemical vapor deposition, low-pressure chemical vapor deposition, or thermal atomic layer deposition.

[0084] The present invention performs a pretreatment before forming the thin film 32 to change the chemical bonds on the substrate surface (i.e., the sidewalls and bottom of the trench 31 and the surface of the stacked structure 20) of the thin film 32 to be formed, thereby increasing the deposition rate of the thin film 32, thereby reducing the manufacturing cost of the thin film 32 and improving the manufacturing efficiency of the semiconductor structure.

[0085] In one embodiment of the present invention, after the trench 31 is formed, different pretreatments are performed to verify the deposition rate of the thin film. The first group undergoes no pretreatment, the second group undergoes pretreatment with DIW (deionized water), the third group undergoes pretreatment with DHF, and the fourth group undergoes pretreatment with SPM. Then, based on the four pretreatment groups, the same deposition method and the same deposition time are used to form the thin film 32. The thickness of the thin film on the sidewalls and top of the trench 31 in each group is then measured to verify the deposition rate.

[0086] Figures 9a to 9d This is a schematic diagram of different groups of semiconductor structures provided in one embodiment of the present invention. The thickness of the thin film 32 formed in each group was measured. Please refer to... Figure 9a As shown, the first group does not undergo pretreatment, and the thickness of the film 32 at the top of the trench 31 is... The thickness of the film 32 on the side of the trench 31 is Please refer to Figure 9b As shown, the second group is pretreated using DIW, and the thickness of the film 32 at the top of the trench 31 is... The thickness of the film 32 on the side of the trench 31 is Please refer to Figure 9c As shown, the third group uses DHF for pretreatment, and the thickness of the film 32 at the top of the trench 31 is... The thickness of the film 32 on the side of the trench 31 is Please refer to Figure 9d As shown, the fourth group is pretreated using SPM, and the thickness of the film 32 at the top of the trench 31 is... The thickness of the film 32 on the side of the trench 31 is

[0087] The above verification results show that the thickness of the thin film 32 formed after pretreatment with DHF and SPM is much greater than the thickness of the thin film 32 formed without pretreatment or with DIW pretreatment. That is, pretreatment of the substrate with a cleaning agent containing hydrogen ions can change the chemical bonds on the substrate surface that inhibit thin film deposition, specifically converting the Si-OH bonds on the substrate surface into Si-H bonds, thereby improving the adsorption efficiency of the precursor gas, increasing the deposition rate of the thin film, reducing the fabrication cost of the thin film, and improving the fabrication efficiency of the semiconductor structure.

[0088] In summary, the thin film fabrication method provided by the present invention first pre-treats the substrate to change the chemical bonds on the substrate surface that inhibit the deposition of the thin film, and then forms the thin film on the substrate. This can improve the deposition rate of the thin film, thereby reducing the fabrication cost of the thin film and increasing the hourly yield of wafers.

[0089] Furthermore, by pretreating the substrate, the chemical bonds on the substrate surface that inhibit film deposition are altered. The substrate with altered chemical bonds exhibits higher adsorption efficiency for precursor gases than the substrate without altered chemical bonds. In other words, the adsorption of precursor gases is enhanced by altering chemical bonds, thereby increasing the film deposition rate.

[0090] The semiconductor structure fabrication method provided by this invention first provides a substrate, on which a stacked structure comprising at least an oxide layer, a nitride layer, and an oxide layer is formed. Next, the stacked structure is etched to form trenches exposing the substrate. Then, a pretreatment is performed to alter the chemical bonds on the trench sidewalls, bottom, and the exposed substrate surface that inhibit thin film deposition. Finally, a thin film is formed, covering the trench sidewalls, bottom, and the substrate surface. This invention performs pretreatment before thin film formation to alter the chemical bonds on the substrate and trench surface, thereby increasing the thin film deposition rate, reducing fabrication costs, and improving the efficiency of semiconductor structure fabrication.

[0091] 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 thin film, characterized in that, Includes the following steps: A substrate is provided, and the substrate is pretreated to change the chemical bonds on the substrate surface that inhibit thin film deposition; as well as A thin film is formed on the substrate.

2. The method for manufacturing a thin film according to claim 1, characterized in that, Changing the chemical bonds on the substrate surface that inhibit thin film deposition includes: converting the Si-H bonds on the substrate surface into Si-OH bonds, or converting the Si-OH bonds on the substrate surface into Si-H bonds.

3. The method for manufacturing a thin film according to claim 1, characterized in that, The thin film includes a silicon nitride thin film, and the pretreatment includes converting Si-OH bonds on the substrate surface into Si-H bonds.

4. The method for manufacturing a thin film according to claim 3, characterized in that, The pretreatment includes pre-cleaning the substrate using a cleaning agent containing hydrogen ions.

5. The method for manufacturing a thin film according to claim 4, characterized in that, Cleaning agents containing hydrogen ions include DHF or SPM.

6. The method for manufacturing a thin film according to claim 1, characterized in that, Before pretreating the substrate, the fabrication method further includes forming a silicon oxide layer on the substrate.

7. The method for manufacturing a thin film according to claim 1, characterized in that, A thin film is formed on the substrate using plasma-enhanced chemical vapor deposition, low-pressure chemical vapor deposition, plasma-enhanced atomic layer deposition, or thermal atomic layer deposition.

8. The method for manufacturing a thin film according to claim 1, characterized in that, The step of forming a thin film on the substrate includes: The substrate is placed inside the reaction chamber; A precursor gas is introduced into the reaction chamber, and the precursor gas is adsorbed onto the surface of the substrate. The adsorption efficiency of the substrate for the precursor gas after the chemical bond change is higher than that of the substrate before the chemical bond change. A reaction gas is introduced into the reaction chamber, and the reaction gas is ionized to form plasma, which reacts with the precursor gas to form a thin film.

9. The method for manufacturing a thin film according to claim 8, characterized in that, The precursor gas includes P41, and the reactant gas includes nitrogen.

10. A method for fabricating a semiconductor structure, characterized in that, Includes the following steps: A substrate is provided, on which a stacked structure comprising at least an oxide layer, a nitride layer and an oxide layer is formed; The stacked structure is etched to form trenches that expose the substrate; Pretreatment is performed to alter the chemical bonds on the trench sidewalls, bottom, and surface of the stacked structure that inhibit thin film deposition; as well as A thin film is formed, which covers the sidewalls and bottom of the trench and the stacked structure.

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