阅读说明：本技术 在处理腔室内的等离子体致密化 (Plasma densification within a processing chamber ) 是由 B·S·权 D·H·李 P·K·库尔施拉希萨 K·D·李 R·林杜尔派布恩 I·贾米尔 于 2020-03-25 设计创作，主要内容包括：一种用于形成膜的系统和方法包含以下步骤：在处理腔室的处理容积中产生等离子体以在基板上形成膜。处理腔室可包含：气体分配器,气体分配器被配置成在处理容积中产生等离子体。再者,将阻挡气体提供至处理容积以在位于处理容积中的等离子体周围形成气幕。阻挡气体是由气体供应源经由沿着处理腔室的第一侧设置的入口端口来供应。此外,排气口是沿着处理腔室的第一侧来设置,且等离子体和阻挡气体是通过排气口被清除。(A system and method for forming a film comprising the steps of: a plasma is generated in a processing volume of a processing chamber to form a film on a substrate. The processing chamber may comprise: a gas distributor configured to generate a plasma in the processing volume. Further, a barrier gas is provided to the processing volume to form a gas curtain around a plasma located in the processing volume. The barrier gas is supplied by a gas supply source via an inlet port disposed along a first side of the process chamber. Further, an exhaust port is disposed along the first side of the processing chamber, and the plasma and barrier gases are purged through the exhaust port.)

1. A method for forming a film, the method comprising the steps of:

generating a plasma in a processing volume of a processing chamber to form the film on a substrate;

introducing a barrier gas into the processing volume of the processing chamber via an inlet port from a first side of the processing chamber to create a gas curtain along one or more edges of the substrate during a time period that overlaps with the creation of a plasma in the processing volume; and

the plasma and the barrier gas are purged through an exhaust of the processing chamber.

2. The method of claim 1, wherein the step of generating the plasma comprises the steps of: ionizing a process gas flowing through a gas distributor of the process chamber.

3. The method of claim 2, wherein the substrate is disposed on a substrate support of the process chamber, and wherein the substrate is disposed between the gas distributor and the first side.

4. The method of claim 2, wherein a flow rate of the barrier gas is based on at least one of a flow rate of the process gas, a type of the barrier gas, and a type of the process gas.

5. The method of claim 1, wherein the barrier gas is one of helium, hydrogen, nitrogen, argon, oxygen, or nitrogen oxide.

6. The method of claim 1, wherein the barrier gas is an inert gas.

7. The method of claim 1, wherein generating the gas curtain along the one or more edges of the substrate increases a uniformity of a density of the plasma over the substrate.

8. The method of claim 7, wherein increasing the uniformity of the density of the plasma over the substrate increases uniformity of a thickness of the film formed on the substrate.

9. A processing chamber, comprising:

a gas distributor configured to generate a plasma within a processing volume by ionizing a process gas;

a substrate support configured to support a substrate within the processing volume;

a gas inlet port disposed along a first wall of the process chamber; and

a gas supply coupled to the gas inlet port and configured to introduce a barrier gas into the processing volume to generate a gas curtain along one or more edges of the substrate during a time period that overlaps with the generation of the plasma within the processing volume.

10. The processing chamber of claim 9, wherein the first wall of the processing chamber is opposite the gas distributor.

11. The processing chamber of claim 9, wherein the gas supply is configured to supply the barrier gas at a flow rate based on at least one of a flow rate of the process gas, a type of the barrier gas, and a type of the process gas.

12. The processing chamber of claim 9, wherein the barrier gas is one of helium, hydrogen, nitrogen, argon, oxygen, or an oxynitride.

13. The processing chamber of claim 9, wherein generating the gas curtain along the one or more edges of the substrate increases a uniformity of a density of the plasma over the substrate.

14. The processing chamber of claim 9, further comprising:

a shield disposed within the processing volume and surrounding the substrate support, the shield configured to control a flow of the barrier gas; and

an exhaust port disposed along the first wall of the process chamber.

15. A processing chamber, comprising:

a gas distributor configured to provide a process gas to a process volume for generating a plasma;

a substrate support configured to support a substrate within the processing volume;

a gas inlet port disposed along a first wall of the process chamber;

a gas supply configured to introduce a barrier gas into the processing volume of the processing chamber to generate a gas curtain along one or more edges of the substrate during a time period that overlaps with the generation of the plasma within the processing volume;

a shield disposed within the processing volume and surrounding the substrate support, the shield configured to control a flow of the barrier gas to form the gas curtain; and

an exhaust port disposed along the first wall of the process chamber.

Technical Field

Embodiments of the present disclosure generally relate to depositing thin films on semiconductor substrates.

Description of the Related Art

Plasma Enhanced Chemical Vapor Deposition (PECVD) may be used to form one or more films on a substrate for semiconductor device fabrication. In many cases, when performing PECVD, a plasma is generated within the processing chamber to form a film or films on the substrate. Further, the uniformity of the one or more parameters of the film corresponds to the uniformity of the density of the plasma. Thus, any difference in plasma density may cause one or more parameters of the film or films to change. In one example, non-uniform plasma density can produce films with non-uniform edge-to-edge thickness, which can result in processed substrates that are not suitable for use in semiconductor device fabrication. Therefore, the yield may be reduced, and the manufacturing cost may be increased.

Accordingly, there remains a need in the art for improved methods of forming thin films on semiconductor substrates and hardware components.

Disclosure of Invention

In one embodiment, a method for forming a film comprises the steps of: the method includes generating a plasma in a processing volume of a processing chamber to form a film on a substrate, introducing a barrier gas into the processing volume of the processing chamber through an inlet port from a first side of the processing chamber to generate a gas curtain along one or more edges of the substrate, and purging the plasma and the barrier gas through an exhaust port along the first side of the processing chamber.

In one embodiment, a processing chamber comprises: a substrate support configured to support a substrate within a processing volume of the processing chamber, a gas inlet port disposed along a first side of the processing chamber, and an exhaust port disposed along the first side of the processing chamber. The gas inlet port is configured to be coupled to a gas supply configured to introduce a barrier gas into the processing volume of the processing chamber to create a gas curtain along one or more edges of the substrate.

In one embodiment, a processing chamber comprises: a gas distributor, a substrate support, a gas inlet, a gas supply, and an exhaust. The gas distributor is configured to generate a plasma within a processing volume of the processing chamber by ionizing a process gas. The substrate support is configured to support a substrate within a processing volume of the processing chamber. The gas inlet port is disposed along a first side of the processing chamber. The gas supply is coupled to the gas inlet port and configured to introduce a barrier gas into the processing volume of the processing chamber to create a gas curtain along one or more edges of the substrate. The exhaust port is disposed along the first side of the processing chamber.

Drawings

So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. However, it should be noted that: the appended drawings illustrate only exemplary embodiments and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.

Fig. 1 and 2 are schematic cross-sectional views of a substrate processing system in accordance with one or more embodiments.

FIG. 3 illustrates a top view of a substrate and an air curtain in accordance with one or more embodiments.

Fig. 4 illustrates a flow diagram of a method of forming a film in accordance with one or more embodiments.

To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.

Detailed Description

The semiconductor device may be produced by forming one or more films on a substrate, and may include: films comprising silicon, nitride, and oxide, and the like. A processing chamber for processing a substrate may be configured to perform operations including Chemical Vapor Deposition (CVD) including plasma enhanced CVD (pecvd), Plasma Enhanced Atomic Layer Deposition (PEALD), or Physical Vapor Deposition (PVD). The quality of the film on the substrate may be negatively affected based on differences and non-uniformities in the plasma density of the plasma above the substrate within the processing chamber. Differences in plasma density within the processing volume of a processing chamber can negatively affect edge-to-edge uniformity of films formed on substrates. In addition, any non-uniformity of the film may cause a decrease in yield, thereby increasing the manufacturing cost of the semiconductor device.

Using the systems and methods discussed herein, the uniformity of the density of plasma within the processing volume (particularly plasma on a substrate) can be significantly improved. Uniformity can be improved for a particular process, for example, by introducing a barrier gas into the processing volume to create a gas curtain that reduces the dispersion of the plasma within the processing volume. The reduced dispersion of the plasma within the processing volume increases the uniformity of the plasma over the substrate. In various embodiments, the reduced dispersion of the plasma within the processing volume (e.g., increased densification of the plasma within the processing volume) results in an increase in the deposition rate of about 20% as compared to a processing system that does not include techniques to reduce the dispersion of the plasma. Furthermore, reducing the dispersion of the plasma can actively adjust film properties (e.g., refractive index (n), stress, and extinction coefficient (k)) due in part to increased deposition uniformity of the formed film.

Fig. 1 illustrates a schematic cross-sectional view of a processing chamber 100 according to one implementation described herein. The processing chamber 100 is a PECVD chamber, but may be another plasma enhanced processing chamber. The processing chamber 100 has a chamber body 102, a substrate support 104 disposed inside the chamber body 102, and a lid assembly 106 coupled to the chamber body 102 and enclosing the substrate support 104 in a processing volume 120. The substrate support 104 is configured to support a substrate 154 thereon during processing. The substrate 154 is provided to the processing volume 120 via the opening 126. Although the implementation of fig. 1 is directed to a PECVD chamber, the lid assembly 106 and the substrate support 104 of fig. 1 may be used with other processing chambers that utilize a plasma generated in the processing volume 120.

The gas supply source 111 includes: one or more gas sources. The gas supply 111 is configured to deliver one or more gases from one or more gas sources to the process volume 120. Each of the one or more gas sources provides a process gas (e.g., argon, hydrogen, or helium) that can be ionized for plasma formation. For example, one or more of a carrier gas and an ionizable gas may be provided to the processing volume 120 along with one or more precursors. When processing a 300mm substrate, the process gas is introduced into the processing chamber 100 at a flow rate of from about 6500sccm to about 8000sccm, from about 100sccm to about 10,000sccm, or from about 100sccm to about 1000 sccm. Alternatively, other flow rates may be utilized. In some examples, a remote plasma source may be used to deliver plasma to the processing chamber 100 and may be coupled to the gas supply 111.

The gas distributor 112 has openings 118 for allowing process gas (or gases) to enter the process volume 120 from the gas supply 111. Process gases are supplied to the process chamber 100 through conduit 114 and enter a gas mixing zone 116 before flowing through openings 118.

The electrode 108 is disposed adjacent to the chamber body 102 and separates the chamber body 102 from the other components of the lid assembly 106. The electrode 108 is part of the lid assembly 106, but may be a separate sidewall electrode. The electrode 108 may be an annular, or ring-shaped member, and may be a ring-shaped electrode. The electrode 108 may be a continuous ring around the perimeter of the processing chamber 100 surrounding the processing volume 120, or may be discontinuous at selected locations. The electrode 108 may also be a perforated electrode (e.g., a perforated ring or mesh electrode). The electrode 108 may also be a plate electrode (e.g., a secondary gas distributor).

The electrode 108 is coupled to a power source 128. The power source 128 is a Radio Frequency (RF) power source electrically coupled to the electrode 108. In addition, the power source 128 provides between about 100Watt and about 3,000Watt at a frequency of about 50kHz to about 13.6 MHz. Alternatively, the power source 128 may be pulsed during various operations. The electrode 108 and power source 128 facilitate additional control of the plasma formed within the processing volume 120.

The substrate support 104 comprises: one or more metallic or ceramic materials, or formed from one or more metallic or ceramic materials. Exemplary metallic or ceramic materials include: one or more metals, metal oxides, metal nitrides, metal oxynitrides, or any combination thereof. For example, the substrate support 104 may include: aluminum, aluminum oxide, aluminum nitride, aluminum oxynitride, or any combination thereof, or formed from aluminum, aluminum oxide, aluminum nitride, aluminum oxynitride, or any combination thereof.

The electrode 122 is embedded within the substrate support 104, but may alternatively be coupled to a surface of the substrate support 104. The electrode 122 is coupled to a power source 136. The power source 136 is DC power, pulsed DC power, Radio Frequency (RF) power, pulsed RF power, or any combination thereof. The power source 136 is configured to drive the electrode 122 with a drive signal to generate a plasma within the processing volume 120. The drive signal may be one of a DC signal and a varying voltage signal (e.g., an RF signal). Further, the electrode 122 may alternatively be coupled to the power source 128 (rather than the power source 136), and the power source 136 may be omitted.

A plasma is generated in the processing volume 120 by the power source 128 and the power source 136. An RF field is established by driving at least one of electrode 108 and electrode 122 with a drive signal to facilitate formation of a capacitive plasma within processing volume 120. The presence of the plasma facilitates processing of the substrate 154 (e.g., deposition of a film to the surface of the substrate 154).

One or more gas inlet ports 152 are coupled to a gas supply 153 and disposed within the bottom chamber wall 101 of the processing chamber 100 below the substrate support 104. A gas supply 153 provides one or more gases to the processing volume 120 via a gas inlet port 152. For example, the gas supply 153 provides a barrier gas to the process volume 120. The barrier gas is any gas that does not significantly interact (e.g., mix) with the plasma and is capable of forming a gas curtain around the substrate 154 while mitigating the dispersion of the plasma within the processing volume 120. For example, the gas that does not significantly interact with the plasma may be any gas that at least partially slows the dispersion of the plasma within the processing volume 120. Further, the barrier gas may be any gas that reduces the formation of parasitic plasma. Further, the barrier gas may be an inert gas. Alternatively, or additionally, the barrier gas may be helium, hydrogen, nitrogen, argon, oxygen, or Nitrogen Oxides (NO)_x) And so on. Gas supplyThe source 153 controls the type of barrier gas and the flow rate of the barrier gas into the processing volume 120 to control one or more parameters of the gas curtain created by the barrier gas. Additionally, the barrier gas may function as a purge gas to facilitate removal of gases, plasma, or process byproducts from the processing volume 120.

The shield (or ring) 160 directs the barrier gas to flow along the periphery of the substrate support 104 and the periphery of the substrate 154. For example, the shield 160 may control the flow of the barrier gas such that the barrier gas flows along the perimeter of the substrate support 104 and the perimeter of the substrate 154 before being dispersed within the processing volume 120. The shield 160 is coupled to the chamber wall 101. Alternatively, the shield 160 may be coupled to another chamber wall of the processing chamber 100. As shown, the shield 160 circumscribes the substrate support 104.

The exhaust port 156 is coupled to the vacuum pump 157 and is disposed along the same wall of the processing chamber 100 (e.g., the chamber wall 101) (as the gas inlet port 152). Alternatively, the exhaust port 156 may be disposed along another wall of the processing chamber 100 so long as the flow of the barrier gas along the periphery of the substrate 154 is not negatively affected, thereby preventing the gas curtain 214 of fig. 2 from being formed. The vacuum pump 157 removes excess process gases or byproducts from the process volume 120 through an exhaust port 156 during and/or after processing.

Figure 2 illustrates a schematic cross-sectional view of the processing chamber 100 and how the gases flow within the processing chamber 100 and create a gas curtain within the processing chamber 100, in accordance with one or more embodiments. One or more process gases flow from the gas supply 111 along a path 210 and through the gas distributor 112 to facilitate processing of the substrate 154. The process gas is converted to a plasma in a plasma region 220 above the substrate 154 in the processing volume 120 of fig. 1. A barrier gas is provided through the gas inlet port 152 to act as a purge gas to help remove excess process gas or byproducts from the process volume 120 through the exhaust port 156 during and/or after processing and also to create a gas curtain 214. The barrier gas flows along path 212 (e.g., paths 212a and 212 b). As the barrier gas is reduced, dispersion of the plasma throughout the processing chamber is achieved. For example, the barrier gases may not interact (e.g., mix) due to differences in electronegativity between the barrier gases and the process gases. In addition, reducing the plasma dispersion throughout the processing chamber increases the uniformity of the plasma density within the plasma region 220 above the substrate. For example, the density of the plasma along the edge of the substrate 154 may be similar to the density of the plasma near the center of the substrate 154. Furthermore, films formed from plasmas having more uniform densities may have more uniform edge-to-edge thicknesses or k-values. For example, the thickness of the film and/or the k value of the film along the edge of the substrate 154 may be similar to the thickness of the film and/or the k value of the film near the center of the substrate 154. Further, the deposition rate of films formed from plasmas having a more uniform density can be about 20% higher than the deposition rate of films formed from plasmas that do not have a uniform density, while maintaining similar film quality.

The gas curtain 214 acts as a flow resistor (choke) to reduce the plasma dispersion within the processing volume 120, to densify the plasma within the plasma region 220 and to increase the uniformity of the plasma density within the plasma region 220. In addition, an air curtain may be created around the entire perimeter of the substrate 154. Reducing the plasma dispersion within the processing volume traps the plasma and increases the uniformity of the plasma within the plasma region 220. Thus, the deposition uniformity of the corresponding film is increased. Further, reducing the dispersion of the plasma increases the quality of the plasma by increasing the rate and/or k-value of the deposition of the film formed on the substrate. Further, a shape of a cross section of an edge-to-edge thickness profile of a film formed on the substrate within the process chamber using the barrier gas is flatter than a shape of a cross section of an edge-to-edge thickness profile of a film formed on the substrate within the process chamber not using the barrier gas. Further, a k-value profile of a film formed on the substrate in the process chamber using the barrier gas is larger than a k-value profile of a film formed on the substrate in the process chamber not using the barrier gas.

The flow rate and type of the barrier gas may correspond to an amount that prevents the plasma from being dispersed within the processing volume 120, and may correspond to a uniformity of plasma density. For example, a higher flow rate may provide a greater reduction in the amount by which the plasma is dispersed and a greater increase in the uniformity of the plasma density (as compared to a lower flow rate). The flow rate of the barrier gas can be in a range of about 100sccm to about 5000 sccm. In one example implementation, when the flow rate of the process gas is about 3 liters, the flow rate of the barrier gas may be in a range between about 100sccm to about 1000sccm (depending on the type of process gas utilized). Further, the flow rate of the barrier gas may be less than the flow rate of the process gas. For example, the flow rate of the barrier gas may be a percentage of the flow rate of the process gas. An example flow rate of the barrier gas may be in a range of about 10% to about 80% of the process gas. Alternatively, percentages less than 10% and greater than 80% may be utilized.

Furthermore, different types of barrier gases may prevent different amounts of plasma from being dispersed and provide a greater increase in the uniformity of plasma density within the processing volume 120. Further, the flow rate of the barrier gas may be based on at least one of: the type of barrier gas utilized, the type of gas used to generate the plasma, the flow rate of the process gas, and the amount of plasma dispersion to be prevented. For example, the flow rate of the first barrier gas utilized with the first process gas may be different than the flow rate of the first barrier gas utilized with the second process gas. Further, the flow rate of the first barrier gas utilized with the first process gas may be different than the flow rate of the second barrier gas utilized with the first process gas. The type of barrier gas may be selected based on the electronegativity of the process gas (or gases). For example, the barrier gas may be selected based on a difference in electronegativity between the process gas and the barrier gas. Furthermore, the barrier gas may be selected to maximize the difference in electronegativity between the process gas and the barrier gas. Further, the barrier gas may be selected according to the drive signal utilized to convert the process gas into a plasma. For example, the barrier gas can be selected such that it does not ionize (e.g., ignite) into a plasma in the presence of a drive signal utilized to convert the process gas into a plasma.

FIG. 3 illustrates a top view of an air curtain 214 in accordance with one or more embodiments. As shown by fig. 3, the substrate 154 is surrounded by an air curtain 214. Alternatively, the gas curtain 214 may partially surround the substrate 154. Further, the thickness of the curtain of gas 214 may be substantially uniform, or non-uniform. Additionally, or alternatively, the distance between the base plate 154 and the gas curtain 214 may be substantially uniform or non-uniform.

As discussed herein, the film deposition operation may comprise: formation of one or more films on a substrate 154 disposed on the substrate support 104. Fig. 4 is a flow diagram of a method 400 for processing a substrate in accordance with one or more embodiments. The method 400 may be utilized to form one or more films on the substrate 154. For example, a substrate 154 may be disposed within the processing chamber 100 to form one or more films on the substrate 154.

At operation 410, a plasma is generated in the processing volume 120 of the processing chamber 100. For example, one or more process gases may be introduced into the process chamber 100 from a gas supply 111. The process gas may comprise: one or more of the at least one precursor gas, the ionizable gas, and the carrier gas may be ionized to form a plasma. For example, the electrode 122 may be driven by the power source 136 and with an RF signal to ionize the process gas (or gases) into a plasma. In addition, the precursor gas LG may be utilized in the presence of plasma to form a film on a substrate. For example, the power sources 128 and 136 may be driven while process gases are introduced into the processing chamber 100 to generate a plasma.

At operation 420, a barrier gas is introduced into the process volume 120 of the process chamber 100. For example, a barrier gas may be introduced into the processing volume 120 of the processing chamber 100 by a gas supply 153 via a gas inlet port 152. The barrier gas may create a gas curtain (e.g., gas curtain 214) that reduces the dispersion of the plasma within the processing volume 120, thereby increasing the uniformity of the density of the plasma over the substrate 154. For example, the gas curtain 214 may act as a choke to reduce the amount of parasitic plasma formed near the edge of the substrate 154 and increase the uniformity of the density of the plasma within the plasma region 220. Thus, edge-to-edge uniformity of one or more parameters of the film formed on the substrate 154 is also increased. For example, edge-to-edge uniformity of the thickness of the film may be increased. Alternatively, or additionally, edge-to-edge uniformity of the k-value of the film may be increased. In addition, the increase in uniformity of density may produce localized plasma densification that may improve plasma quality and increase the corresponding deposition rate of the film, thereby improving one or more parameters of the film.

The flow rate of the barrier gas may be selected based on the type of process gas, the type of barrier gas, and/or the flow rate of the process gas. The flow rate of the barrier gas may be less than the flow rate of the process gas. Further, the flow rate of the barrier gas may be a percentage of the flow rate of the process gas. Additionally, or alternatively, the flow rate of the barrier gas may correspond to an amount by which the plasma is densified over the substrate 154. For example, the flow rate of the barrier gas may be adjusted to maintain a substantially uniform plasma density over the substrate 154. For example, the flow rate of the barrier gas may be adjusted to maintain a plasma density within about 5% of optimal uniformity. Further, the flow rate of the barrier gas may be increased when the uniformity of the plasma density is less than a first threshold and when the increased plasma density is greater than a second threshold. When 2 thresholds are discussed, alternatively, more than 2 thresholds or less than 2 thresholds may be utilized.

At operation 430, the plasma and barrier gases are purged from the processing chamber 100. For example, the exhaust port 156 can be coupled to a vacuum pump 157, and the vacuum pump 157 removes excess process gases or byproducts from the process volume 120 through the exhaust port during and/or after processing.

Thus, using the systems and methods discussed herein, the uniformity of the density of the plasma can be increased within the processing volume of the processing chamber by introducing a barrier gas, thereby increasing the uniformity of the corresponding film or films produced on the substrate. In addition, the deposition rate of the film is increased. Accordingly, the yield of the corresponding semiconductor device can be increased, and the manufacturing cost can be reduced. The barrier gas may create a gas curtain, or choke, to reduce the dispersion of the plasma within the processing volume, thereby increasing the uniformity of the density of the plasma over the substrate.

While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.