Coil for generating a radio frequency field

Abstract

According to some embodiments, a coil for generating a radio frequency (RF) field within a semiconductor device is provided. The coil may comprise a tubular portion formed in two turns, the two turns configured to surround a plasma vessel of a semiconductor manufacturing apparatus, the second end of the tubular portion being bent toward the first end of the tubular portion, and the first end and the second end of the tubular portion being bent at an angle from the two turns. The coil may comprise a first terminal attached to the first end of the tubular portion, configured to be operably coupled to an RF source. The coil may comprise a second terminal attached to the second end of the tubular portion, configured to be operably coupled to ground.

Description

Background Art

[0001] Plasma-based operations are frequently used in semiconductor device manufacturing. Plasma non-uniformity can lead to detrimental defects in fabricated devices, for example due to non-uniform deposition or etching.

[0002] The description of the background art provided herein is for the purpose of generally presenting the context of the present disclosure. To the extent described in this Background Art section, the work of the present inventors, as well as aspects of the description that may not qualify as prior art at the time of filing, are neither expressly nor implicitly admitted as prior art to the present disclosure.

Summary of the Invention

Means for Solving the Problems

[0003] According to some embodiments, a coil for generating a radio frequency (RF) field within a semiconductor device is provided. The coil may comprise a tubular portion formed into 2 turns, the 2 turns being configured to surround a plasma container of a semiconductor manufacturing apparatus, a second end of the tubular portion being bent toward a first end of the tubular portion, and the first end of the tubular portion and the second end of the tubular portion being bent at an angle from the 2 turns. The coil can comprise a first terminal attached to the first end of the tubular portion, the first terminal being configured to be operatively coupled to an RF source. The coil can comprise a second terminal attached to the second end of the tubular portion, the second terminal being configured to be operatively coupled to ground.

[0004] In some examples, the second end of the tubular portion is bent such that the second end overlaps the first end of the tubular portion.

[0005] In some examples, the tubular portion comprises a metal.

[0006] In some examples, the tubular portion comprises one of ultra-high conductivity copper or silver-plated stainless steel.

[0007] In some examples, the first terminal is welded to the first end of the pipe section, and the second terminal is welded to the second end of the pipe section.

[0008] In some examples, the first end of the tube section is bent at an angle ranging from approximately 60 to 100 degrees, starting from two turns.

[0009] In some examples, the second end of the tube section is bent at an angle ranging from two turns to approximately 60 to 100 degrees.

[0010] A method is provided for forming a coil for generating an RF field within a semiconductor manufacturing apparatus. In some embodiments, the method includes the step of forming a tubular portion of the coil from a single tubular piece such that the tubular portion forms two turns. The method may further include the step of bending a second end of the tubular portion toward a first end of the tubular portion. The method may further include the step of bending the second end and the first end of the tubular portion at an angle with respect to the two turns. The method may further include the step of attaching a first terminal to the first end of the tubular portion and a second terminal to the second end of the tubular portion.

[0011] In some examples, the second end of the tube section is bent so that the second end overlaps with the first end of the tube section.

[0012] In some examples, the tubular portion contains highly conductive copper.

[0013] In some examples, the tubing includes silver-plated stainless steel.

[0014] In some examples, the first terminal is welded to the first end of the pipe section, and the second terminal is welded to the second end of the pipe section.

[0015] In some examples, the first end of the tube section is bent at an angle ranging from approximately 60 to 100 degrees, starting from two turns.

[0016] In some examples, the second end of the tube section is bent at an angle ranging from two turns to approximately 60 to 100 degrees.

[0017] According to several embodiments, a semiconductor processing tool is provided. The tool may comprise an RF source, one or more process stations, each configured to receive and process a semiconductor wafer, one or more receptacles configured to receive gas from a gas source, convert the received gas into plasma, and disperse the plasma to one or more process stations, and a coil. The coil may comprise a tubular portion formed in two turns, the two turns configured to surround one of the one or more receptacles, with a second end of the tubular portion bent toward a first end of the tubular portion, and the first end and the second end of the tubular portion bent from the two turns at an angle. The coil may further comprise a first terminal attached to the first end of the tubular portion, configured to be operably coupled to the RF source. The coil may further comprise a second terminal attached to the second end of the tubular portion, configured to be operably coupled to ground.

[0018] In some examples, one or more process stations comprise four process stations.

[0019] In some examples, the second end of the tube section is bent so that the second end overlaps with the first end of the tube section.

[0020] In some examples, the tubular portion contains highly conductive copper.

[0021] In some examples, the tubing includes silver-plated stainless steel.

[0022] In some examples, the first terminal is welded to the first end of the pipe section, and the second terminal is welded to the second end of the pipe section.

[0023] In some examples, the first end of the tube portion is bent at an angle in the range of 2 turns to about 60° to 100°.

[0024] In some examples, the second end of the tube portion is bent at an angle in the range of 2 turns to about 60° to 100°. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] [Figure 1A] FIG. 3 is a diagram showing an example coil for generating a radio frequency (RF) field, according to some embodiments. [Figure 1B] FIG. 4 is another diagram showing an example coil for generating a radio frequency (RF) field, according to some embodiments. [Figure 1C] FIG. 5 is another diagram showing an example coil for generating a radio frequency (RF) field, according to some embodiments. [Figure 2] FIG. 6 is a diagram showing an example of an RF field generated using the coils shown in FIG. 1A, FIG. 1B, and FIG. 1C. [Figure 3A] FIG. 7 is a diagram showing another example coil for generating an RF field, according to some embodiments. [Figure 3B] FIG. 8 is another diagram showing another example coil for generating an RF field, according to some embodiments. [Figure 4] FIG. 9 is a diagram showing an example of an RF field generated using the coils shown in FIG. 3A and FIG. 3B. [Figure 5] FIG. 10 is a top view of an example multi-station process chamber utilizing coils similar to the coils shown in FIG. 3A and FIG. 3B, according to some embodiments. [Figure 6] FIG. 11 is a flowchart of an example process for manufacturing a coil according to some embodiments. DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

[0026] In some semiconductor manufacturing tools, plasma can be generated by generating a radio frequency (RF) field that converts the process gas within a receptacle or vessel into plasma. Note that, as used herein, “receptacle” and “vessel” may be interchangeable. The receptacle or vessel may be referred to as a “plasma vessel.” In this case, the plasma may be used to perform plasma-based manufacturing operations (e.g., deposition or etching operations) on a wafer being processed. The RF field may be generated using a coil placed around the outer portion of the receptacle or vessel. The coil may have a first terminal operably coupled to an RF source (e.g., an RF generator) and a second terminal grounded. Thus, upon receiving an RF signal input to the first terminal, the coil can generate an RF field near and within the receptacle.

[0027] Non-uniformity in the RF field can lead to non-uniformity in the plasma generated by the RF field. Plasma non-uniformity can cause defects in the processed wafer, for example, due to the uneven thickness of layers deposited or etched across the wafer. Therefore, it is important to improve the uniformity of the RF field, and thus the uniformity of the plasma. Figures 1A to 1C show an example of a coil that can generate a non-uniform RF field, particularly in the region adjacent to two terminals of the coil.

[0028] This specification discloses coils and methods for manufacturing coils that result in improved uniformity of the RF field, and therefore improved uniformity of the plasma. In particular, the coils disclosed herein may have terminals that are bent away from the coil turn, and therefore bent at an angle away from the receptacle surrounding the coil turn. Furthermore, the two ends of the coil to which the two terminals are attached may be bent opposite each other and optionally overlap at least to some extent. The angle of the coil ends away from the receptacle and / or the clamping of the two opposite (and possibly overlapping) terminals can help to improve the uniformity of the generated RF field, particularly in the region near the termination. It should be noted that the coil may consist of a single tubular piece rather than multiple parts welded together. The tubing may be made of ultra-high conductive copper or silver-plated stainless steel. An example of a coil according to those disclosed herein is shown in Figures 3A and 3B and described below in relation to those figures, and a method for forming such a coil is shown in Figure 6 and described below in relation to Figure 6.

[0029] Figure 1A shows a receptacle 102 and coil 104 having a first configuration. The receptacle 102 may be made of ceramic or another similar material. The receptacle 102 may be configured to receive gas from a gas source and convert the received gas into plasma. The plasma may then be placed in a process station to perform plasma-based operations (e.g., plasma-based deposition, plasma-based etching operations, etc.) on one or more wafers to be processed. The plasma may be generated using an RF field generated using the coil 104. As shown, the coil 104 is positioned around a portion of the receptacle 102 such that the RF field generated using the coil 104 causes the process gas in the receptacle 102 to be converted into plasma. One terminal of the coil 104 may be operably coupled to an RF source (e.g., an RF generator), and a second terminal of the coil 104 may be operably coupled to ground. Therefore, when coil 104 is coupled to an RF source and receives an RF signal from the RF source, it can then create an RF field that converts the process gas in receptacle 102 into plasma.

[0030] Figure 1B shows a three-dimensional view of coil 104. As shown, the first terminal 122 of coil 104 is operably coupled to an RF source (not shown), and the second terminal 124 of coil 104 is operably coupled to ground (not shown). Note that the receptacle (e.g., receptacle 102 in Figure 1A), if present in the diagram of Figure 1B, is located inside coil 104. Figure 1C shows a top view of coil 104. Figure 1C further shows the RF source 152 to which the first terminal of the coil is operably coupled and the ground to which the second terminal of the coil is operably coupled. The first terminal 122 and the second terminal 124 are positioned in contact with the receptacle. Furthermore, note that due to terminal 122, in some areas coil 104 has two turns, but in areas adjacent to terminal 122 coil 104 has an additional turn, or part of the coil.

[0031] Placing the terminals in contact with the receptacle, as well as coil non-uniformity with respect to the coil's turns, can cause RF field non-uniformity when using the coils shown in Figures 1A, 1B, and 1C. RF field non-uniformity can, in turn, lead to plasma non-uniformity. Plasma non-uniformity can cause defects in the fabricated wafer, such as uneven thickness of deposited or etched material. An example of a non-uniform RF field that can be generated by the coils shown in Figures 1A, 1B, and 1C is shown in Figure 2. Figure 2 is a color scale plot showing the magnitude of the RF field in different regions of the receptacle. Note that the RF field in region 202, corresponding to the coil regions of the first and second terminals, exhibits RF field non-uniformity.

[0032] This specification discloses a coil configured to generate a more uniform RF field within a receptacle and a method for manufacturing such a coil. A more uniform RF field subsequently generates a more uniform plasma, thereby reducing defects in the processed wafer. In some embodiments, the coil disclosed herein has a tubular portion formed into two turns. The two turns may be configured to surround a receptacle (which may also be referred to herein as a “plasma receptacle” and / or “plasma vessel”). A first terminal may be attached to a first end of the tubular portion, which is configured to be operably coupled to an RF source, such as an RF generator. A second terminal may be attached to a second end of the tubular portion, which is configured to be operably coupled to ground. In some embodiments, the tubular portion may be made of ultra-high conductive copper. Alternatively, in some embodiments, the tubular portion may be made of silver-plated stainless steel. The first and second terminals may be welded to the tubular portion. In some embodiments, the first and second ends of the tube may be bent at an angle away from the two turns surrounding the receptacle. By bending the tube away from the receptacle, the tube can have a more uniform number of turns in all areas around the receptacle, thereby resulting in improved uniformity of the RF field. In some embodiments, the first and second terminals may be bent at an angle away from the two turns. The angle may be in the range of about 60 to 100 degrees, about 70 to 90 degrees, or substantially about 90 degrees. In some embodiments, the first and second ends of the tube may be bent so that the first and second ends overlap or are sandwiched together. The overlap of the first and second ends can produce improved uniformity of the RF field, as the first and second ends are operably coupled to the RF source and ground, respectively.

[0033] Figures 3A and 3B show an example coil 302 for generating an RF field according to several embodiments. As shown in Figure 3A, the first end of the coil 302 is bent away from two turns of the coil 302 in section 304. The first end of the coil 302 is terminated at a first terminal 306 configured to be operably coupled to an RF source. The second end of the coil 302 is bent away from two turns of the coil 302 in section 308. The second end of the coil 302 is terminated at a second terminal 310 configured to be operably coupled to ground. Note that by bending the ends of the tube away from two turns of the coil, the coil exhibits greater uniformity in the turns around the receptacle which will be located within two turns, resulting in a higher uniformity of the generated RF field compared to the coil shown in Figures 1A and 1C and described above in relation to these figures. Furthermore, it should be noted that the ends of the coil 302 are overlapped, as shown in Figure 3A, which further enhances the uniformity of the RF field.

[0034] Figure 3B shows a diagram of the coil 302 around the receptacle 354. Note that the turns of the coil 302 are more uniform around the region of the receptacle 354 than the coil shown in Figure 1A and described above in relation to Figure 1A.

[0035] Figure 4 shows an example of an RF field generated using the coils shown in Figures 3A and 3B and described above in relation to these figures. As shown in the figure, the RF field in Figure 4 is more uniform in all regions, including the region adjacent to the coil terminals, compared to the RF field shown in Figure 2 and described above in relation to Figure 2.

[0036] In some embodiments, multiple coils, for example, as shown in Figures 3A and 3B and described above in relation to these figures, may be used in multiple stations of a multi-station process chamber. For example, each station may have a plasma receptacle, and coils may be arranged around a portion of the plasma receptacle of the station. As a more specific example, consider a multi-station process chamber having four stations, where there may be four plasma receptacles, each associated with one of the four stations. Continuing this example, each plasma receptacle may have a coil (for example, as shown in Figures 3A and 3B and described above in relation to these figures). Each coil may be operably coupled to an RF source associated with the process chamber. Note that in some embodiments, each station of the multi-station process chamber may have its own RF source.

[0037] Figure 5 shows a top view of an example multi-station process chamber 500 according to several embodiments. The multi-station process chamber 500 includes four process stations, namely station 502, station 504, station 506, and station 508. Each station is associated with coils (e.g., coil 510, coil 512, coil 514, and coil 516) arranged around a region of a plasma receptacle (not shown). While the multi-station process chamber 500 includes four stations, it should be noted that in some embodiments, the multi-station process chamber may include two, six, eight, or other stations.

[0038] In some embodiments, the coil may be formed primarily from a single tube piece rather than from multiple segments connected to each other to form turns in the coil. The single tube piece may be bent to form two turns in the coil. The second end of the tube may then be bent toward the first end of the tube. For example, the second end of the tube may be bent toward the first end such that the first and second ends of the tube overlap to at least some extent. The first and second ends of the tube may be bent at an angle with respect to the two turns such that when the tube is positioned around the region of the plasma receptacle, the first and second ends of the tube are bent toward the plasma receptacle. For example, the first and second ends may be bent at an angle in the range of about 60 to 100 degrees, in the range of about 70 to 90 degrees, or about 90 degrees. A first terminal may be attached to the first end, where the first terminal is configured to be coupled to an RF source. The second terminal may be attached to the second end, where it is configured to be connected to ground. For example, the first and second terminals may be welded to the first and second ends of the pipe, respectively.

[0039] Figure 6 is a flowchart of process example 600 for manufacturing a coil according to several embodiments. In some embodiments, the blocks of process 600 may be executed in an order other than that shown in Figure 6. In some embodiments, two or more blocks of process 600 may be executed substantially in parallel. In some embodiments, one or more blocks of process 600 may be omitted.

[0040] In 602, the tubular portion of the coil may be formed from a single tubular piece. The tubular portion may be formed (e.g., molded) from two turns. The single tubular piece may include ultra-high conductive copper or silver-plated stainless steel. The two turns may be configured to be positioned around a portion of the plasma receptacle.

[0041] In 604, the second end of the tube portion may be bent toward the first end of the tube portion. For example, the second end may be bent such that it overlaps with the first end of the tube portion to at least some extent. As another example, the second end may be bent toward the first end such that the second end and the first end are close together but do not overlap.

[0042] In 606, the first end of the tube portion may be bent at an angle with respect to two turns of the coil, and the second end of the tube portion may be bent at an angle with respect to two turns of the coil. For example, the first and second ends may be bent such that when the coil is positioned around the plasma receptacle, the ends of the tube portion are bent away from the plasma receptacle. In some embodiments, the first and / or second ends may be bent away from two turns of the coil at an angle in the range of about 60 to 100 degrees, about 70 to 90 degrees, or about 90 degrees. In some embodiments, the first end may be bent at a first angle away from two turns of the coil, and the second end may be bent at a second angle away from two turns of the coil, where it should be noted that the first and second angles are different.

[0043] In 608, the first terminal may be attached to the first end of the tube section, and the second terminal may be attached to the second end of the tube section. For example, the first terminal and the second terminal may be welded to the first end and the second end, respectively. As described above, the first terminal may be operably coupled to an RF source. The second terminal may be operably coupled to ground.

[0044] conclusion This description includes numerous specific details to provide a full understanding of the embodiments presented. The disclosed embodiments may be implemented without some or all of these specific details. In other examples, well-known process behaviors were not described in detail to avoid unnecessarily obscuring the disclosed embodiments. While the disclosed embodiments are described in conjunction with specific embodiments, it should be understood that the specific embodiments are not intended to limit the disclosed embodiments.

[0045] Unless otherwise indicated, the method operations and device features disclosed herein include techniques and apparatus commonly used in measurement, semiconductor device manufacturing techniques, software design and programming, and statistics, which are within the scope of the skills of those skilled in the art.

[0046] Unless otherwise defined herein, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Various scientific dictionaries containing the terms included herein are well known and available to those skilled in the art. Any methods and materials similar or equivalent to those described herein may be used in carrying out or testing the embodiments disclosed herein, although only a few methods and materials are described.

[0047] A numerical range includes the number that defines the range. All the largest numerical limits given throughout this specification are intended to include all the lower numerical limits as if such lower numerical limits were explicitly stated herein. All the smallest numerical limits given throughout this specification include all the higher numerical limits as if such higher numerical limits were explicitly stated herein. All numerical ranges given throughout this specification include all the narrower numerical ranges that fall within such wider numerical ranges as if all such narrower numerical ranges were explicitly stated herein.

[0048] The headings provided herein are not intended to limit this disclosure.

[0049] As used herein, the singular terms “a,” “an,” and “the” include plural references unless the context clearly indicates otherwise. As used herein, the term “or” refers to non-exclusive or unless otherwise indicated.

[0050] Various computing elements, including processors, memory, instructions, routines, models, or other components, may be described or claimed as “configured to” perform one or more tasks. In such contexts, the phrase “configured to” is used to imply a structure by indicating that the component contains a structure (e.g., stored instructions, circuits, etc.) that performs one or more tasks while in operation. Thus, a unit / circuit / component can be said to be configured to perform tasks even when the given component is not necessarily currently operating (e.g., not on).

[0051] The constructs used with the language "configured to" can refer to hardware, such as circuits, or memory that stores executable program instructions to perform an operation. Furthermore, "configured to" can refer to a general structure (e.g., a general-purpose circuit) operated by software and / or firmware (e.g., an FPGA or general-purpose processor running the software) to operate in a way that enables it to perform an enumerated task. Additionally, "configured to" can refer to one or more memories or memory elements that store computer-executable instructions for performing an enumerated task. Such memory elements may include memory on a computer chip containing processing logic. In some contexts, "configured to" can also include adapting a manufacturing process (e.g., semiconductor manufacturing equipment) to produce a device (e.g., an integrated circuit) that has been made to perform or execute one or more tasks. [Explanation of symbols]

[0052] 102 Receptacle 104 coils 122 First terminal 124 Second terminal 152 RF Source 202 areas 302 Coil 304 parts 306 First terminal 308 parts 310 Second terminal 500 Multi-Station Process Chambers 502 Process Station 504 Process Station 506 Process Station 508 Process Station 510 coil 512 coil 514 Coil 516 Coil 600 processes

Claims

1. A coil for generating a radio frequency (RF) field within a semiconductor manufacturing apparatus, wherein the coil is A tubular portion formed in two turns, wherein the two turns are configured to surround the plasma container of the semiconductor manufacturing apparatus, the second end of the tubular portion is bent toward the first end of the tubular portion, and the first end and the second end of the tubular portion are bent at a certain angle from the two turns, A first terminal attached to the first end of the tube portion, the first terminal configured to be operably coupled to an RF source, A second terminal attached to the second end of the pipe portion, the second terminal configured to be operably coupled to ground and A coil equipped with a coil.

2. The coil according to claim 1, wherein the second end of the tube portion is bent such that the second end overlaps with the first end of the tube portion.

3. The coil according to claim 1, wherein the tubular portion includes metal.

4. The coil according to claim 3, wherein the tubular portion includes either ultra-high conductive copper or silver-plated stainless steel.

5. The coil according to any one of claims 1 to 4, wherein the first terminal is welded to the first end of the tube portion, and the second terminal is welded to the second end of the tube portion.

6. The coil according to any one of claims 1 to 4, wherein the first end of the tube portion is bent at an angle within the range of approximately 60 to 100 degrees from the two turns.

7. The coil according to any one of claims 1 to 4, wherein the second end of the tube portion is bent at an angle within the range of approximately 60 to 100 degrees from the two turns.

8. A method for forming a coil for generating a radio frequency (RF) field within a semiconductor manufacturing apparatus, wherein the method is: The steps include forming the tube portion of the coil with a single tube piece such that the tube portion forms two turns, The steps include bending the second end of the pipe portion toward the first end of the pipe portion, The steps include bending the second end and the first end of the pipe portion at a certain angle with respect to the two turns, The steps include attaching a first terminal to the first end of the pipe portion and attaching a second terminal to the second end of the pipe portion. Methods that include...

9. The method according to claim 8, wherein the second end of the pipe portion is bent such that the second end overlaps with the first end of the pipe portion.

10. The method according to claim 8, wherein the tubular portion contains ultra-high conductive copper.

11. The method according to claim 8, wherein the tubular portion includes silver-plated stainless steel.

12. The method according to claim 8, wherein the first terminal is welded to the first end of the pipe portion, and the second terminal is welded to the second end of the pipe portion.

13. The method according to any one of claims 8 to 12, wherein the first end of the pipe portion is bent at an angle within the range of approximately 60 to 100 degrees from the two turns.

14. The method according to any one of claims 8 to 12, wherein the second end of the pipe portion is bent at an angle within the range of approximately 60 to 100 degrees from the two turns.

15. RF source and One or more process stations, each configured to receive and process semiconductor wafers, One or more receptacles configured to receive gas from a gas source, convert the received gas into plasma, and disperse the plasma to one or more process stations, A coil, wherein the coil is A tubular portion formed in two turns, wherein the two turns are configured to surround one of the one or more receptacles, the second end of the tubular portion is bent toward the first end of the tubular portion, and the first end and the second end of the tubular portion are bent at a certain angle from the two turns, A first terminal attached to the first end of the tube portion, the first terminal configured to be operably coupled to the RF source, A second terminal attached to the second end of the pipe portion, the second terminal configured to be operably coupled to ground and A coil and A semiconductor processing tool equipped with the following features.

16. The semiconductor processing tool according to claim 15, wherein the one or more process stations comprises four process stations.

17. The semiconductor processing tool according to claim 15, wherein the second end of the tube portion is bent so that the second end overlaps with the first end of the tube portion.

18. The semiconductor processing tool according to claim 15, wherein the tubular portion contains ultra-high conductive copper.

19. The semiconductor processing tool according to claim 15, wherein the tubular portion includes silver-plated stainless steel.

20. The semiconductor processing tool according to any one of claims 15 to 19, wherein the first terminal is welded to the first end of the tube portion, and the second terminal is welded to the second end of the tube portion.

21. The semiconductor processing tool according to any one of claims 15 to 19, wherein the first end of the tube portion is bent at an angle within the range of approximately 60 to 100 degrees from the two turns.

22. The semiconductor processing tool according to any one of claims 15 to 19, wherein the second end of the tube portion is bent at an angle within the range of approximately 60 to 100 degrees from the two turns.

Images