Methods to improve the performance stability of metal gate devices

Abstract

This application provides a method for improving the performance stability of metal gate devices, comprising: step one, providing a substrate, and sequentially forming a gate oxide layer and a high-k dielectric layer on the substrate; step two, forming a titanium nitride capping layer on the high-k dielectric layer; step three, etching the titanium nitride capping layer with tungsten chloride to improve the uniformity of the titanium nitride capping layer; and step four, forming a dummy gate material layer. Etching the titanium nitride thin film with tungsten chloride (WClx) after deposition improves the uniformity of the titanium nitride thin film, thereby enhancing the performance stability of the metal gate device.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and specifically to a method for improving the performance stability of metal gate devices. Background Technology

[0002] In the front gate process of high-k metal gates, the capping layer (CAP layer) formed on the high-k dielectric layer is a titanium nitride (TiN) film grown by PVD deposition. It serves two purposes: firstly, as an etch stop layer for removing the dummy gate, and secondly, to prevent O diffusion in the high-k dielectric layer. However, due to limitations in the PVD cavity structure and deposition methods (e.g., sputtering), achieving high uniformity in titanium nitride deposition is difficult. Figure 1 As shown, thicker titanium nitride films tend to deposit more readily at the wafer edges. Adjusting various process parameters can slightly improve the deposition morphology, but its effect on uniformity is very limited. Summary of the Invention

[0003] In view of the shortcomings of the prior art described above, the purpose of this application is to provide a method for improving the performance stability of metal gate devices, which solves the problem of poor uniformity of PVD deposited titanium nitride thin films in the prior art.

[0004] To achieve the above and other related objectives, this application provides a method for improving the performance stability of metal gate devices, comprising: Step 1: Provide a substrate, and sequentially form a gate oxide layer and a high-k dielectric layer on the substrate; Step 2: Form a titanium nitride capping layer on the high-k dielectric layer; Step 3: Use tungsten chloride to etch the titanium nitride capping layer to improve the uniformity of the titanium nitride capping layer; Step four: Form a pseudo-gate material layer.

[0005] Preferably, the gate oxide layer is formed using a thermal oxidation process.

[0006] Preferably, a high-k dielectric layer is formed using a chemical vapor deposition process.

[0007] Preferably, the material of the high-k dielectric layer includes hafnium oxide, aluminum oxide, hafnium silicate, zirconium dioxide, or hafnium zirconate.

[0008] Preferably, the titanium nitride coating is formed using a physical vapor deposition process.

[0009] Preferably, a pseudo-gate material layer is formed using a deposition process.

[0010] Preferably, the material of the pseudo-gate material layer includes amorphous silicon.

[0011] As described above, the method for improving the performance stability of metal gate devices provided in this application has the following beneficial effects: after depositing a titanium nitride thin film, tungsten chloride is used to etch it, thereby improving the uniformity of the titanium nitride thin film and achieving the effect of improving the performance stability of the metal gate device. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0013] Figure 1 This diagram illustrates the poor uniformity of PVD-deposited titanium nitride films. Figure 2 The flowchart shown is a method for improving the performance stability of metal gate devices provided in an embodiment of this application. Figure 3 The image shows a comparison of the significant improvement in the uniformity of titanium nitride films compared to existing technologies. Detailed Implementation

[0014] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. This application can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this invention.

[0015] The technical solutions of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0016] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," indicating orientation or positional relationships, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0017] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components; and they can refer to a wireless connection or a wired connection. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0018] Furthermore, the technical features involved in the different embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0019] Please see Figure 2 The flowchart illustrates a method for improving the performance stability of metal gate devices provided in an embodiment of this application.

[0020] like Figure 2 As shown, the method for improving the performance stability of metal gate devices includes the following steps: Step 1: Provide a substrate, and sequentially form a gate oxide layer and a high-k dielectric layer on the substrate; Step 2: Form a titanium nitride capping layer on the high-k dielectric layer; Step 3: Use tungsten chloride to etch the titanium nitride capping layer to improve the uniformity of the titanium nitride capping layer; Step four: Form a pseudo-gate material layer.

[0021] In step one, a substrate is provided. Optionally, the substrate may be a silicon substrate, a germanium substrate, or a silicon-on-insulator substrate, etc.; or the substrate material may also include other materials, such as gallium arsenide or other III-V compounds. Those skilled in the art can select the substrate material according to the type of device structure formed on the substrate, therefore the type of substrate should not limit the scope of protection of this invention.

[0022] For example, a thermal oxidation process is used to form the gate oxide layer.

[0023] Alternatively, the high-k dielectric layer may be made of materials such as, but not limited to, hafnium oxide (HfO2), aluminum oxide (Al2O3), hafnium silicate (HfSiOx), zirconium dioxide (ZrO2), or hafnium zirconium oxide (HfZrOx).

[0024] For example, a high-k dielectric layer is formed using a chemical vapor deposition process.

[0025] In step two, a titanium nitride capping layer is formed using a physical vapor deposition process.

[0026] In step three, due to the physical characteristics of the tungsten chloride etching cavity, tungsten chloride reaction gas is more likely to accumulate in the wafer edge region, thus making it easier for tungsten chloride and titanium nitride to react fully in the wafer edge region. This complements the fact that PVD titanium nitride is easier to deposit a thicker film at the wafer edge, thereby obtaining a smoother titanium nitride film.

[0027] like Figure 3 As shown, compared with the prior art, the method for improving the performance stability of metal gate devices provided in this application can reduce the in-plane range (the difference between the maximum and minimum film thickness) of titanium nitride film obtained by PVD by 50%.

[0028] This method of using tungsten chloride to improve the uniformity of titanium nitride films can also be used in semiconductor manufacturing processes for other unpatterned films in which titanium nitride is used as a constituent material.

[0029] In step four, a dummy gate material layer is formed using a deposition process. For example, the material of the dummy gate material layer includes amorphous silicon.

[0030] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of this application. Therefore, the drawings only show the components related to this invention and are not drawn according to the actual number, shape and size of the components. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0031] In summary, the method for improving the performance stability of metal gate devices provided in this application involves etching the titanium nitride thin film with tungsten chloride after deposition, thereby increasing the uniformity of the titanium nitride thin film and achieving the effect of improving the performance stability of the metal gate device. Therefore, this application effectively overcomes the various shortcomings of the prior art and has high industrial application value.

[0032] The above embodiments are merely illustrative of the principles and effects of this application and are not intended to limit this application. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this application. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this invention should still be covered by the claims of this application.

Claims

1. A method for improving the performance stability of metal gate devices, characterized in that, The method includes: Step 1: Provide a substrate, and sequentially form a gate oxide layer and a high-k dielectric layer on the substrate; Step 2: Form a titanium nitride capping layer on the high-k dielectric layer; Step 3: Use tungsten chloride to etch the titanium nitride coating layer to improve the uniformity of the titanium nitride coating layer; Step four: Form a pseudo-gate material layer.

2. The method according to claim 1, characterized in that, The gate oxide layer is formed using a thermal oxidation process.

3. The method according to claim 1, characterized in that, The high-k dielectric layer is formed using a chemical vapor deposition process.

4. The method according to claim 1 or 3, characterized in that, The high-k dielectric layer is made of hafnium oxide, aluminum oxide, hafnium silicate, zirconium dioxide, or hafnium zirconate.

5. The method according to claim 1, characterized in that, The titanium nitride capping layer was formed using a physical vapor deposition process.

6. The method according to claim 1, characterized in that, The pseudo-gate material layer is formed using a deposition process.

7. The method according to claim 1 or 6, characterized in that, The material of the pseudo-gate material layer includes amorphous silicon.

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