Faraday shield apparatus and semiconductor process chamber

Abstract

This invention discloses a Faraday shielding device and a semiconductor process chamber. The Faraday shielding device (300) is used to shield the electric field generated by the radio frequency coil (200) in the semiconductor process chamber. The Faraday shielding device (300) includes a first shielding plate (310), a second shielding plate (320), and a driving mechanism (330). The first shielding plate (310) has a first opening (311) extending along its thickness direction, and the second shielding plate (320) has a second opening (321) extending along its thickness direction. The driving mechanism (330) is used to change the relative position between the first shielding plate (310) and the second shielding plate (320) to change the overlap between the first opening (311) and the second opening (321). The above solution can solve the problem of poor etching performance in semiconductor process chambers.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing technology, and in particular to a Faraday shielding device and a semiconductor process chamber. Background Technology

[0002] With the rapid development of technology, smartphones, tablets, and other electronic products have become indispensable in modern life. These electronic products contain many semiconductor chips, and the main material for manufacturing semiconductor chips is wafers. Wafers need to be etched with circuit patterns, which is usually done using semiconductor process chambers.

[0003] However, as the depth of the etched wafer circuit pattern increases, the width of the wafer circuit pattern becomes smaller and smaller, thereby reducing the aspect ratio of the wafer etching. As a result, the wafer circuit pattern often forms a "V" shape, which leads to poor etching performance of the semiconductor process chamber and poor wafer yield. Summary of the Invention

[0004] This invention discloses a Faraday shielding device and a semiconductor process chamber to solve the problem of poor etching performance in semiconductor process chambers.

[0005] To solve the above problems, the present invention adopts the following technical solution:

[0006] A Faraday shielding device is provided for shielding the electric field generated by a radio frequency coil in a semiconductor process chamber. The Faraday shielding device includes a first shielding plate, a second shielding plate, and a driving mechanism. The first shielding plate has a first opening extending through its thickness direction, and the second shielding plate has a second opening extending through its thickness direction. The driving mechanism is used to change the relative position between the first shielding plate and the second shielding plate to change the overlap between the first opening and the second opening.

[0007] A semiconductor process chamber includes a cavity, a radio frequency coil, and a dielectric window. The dielectric window is disposed on the top opening of the cavity, and the radio frequency coil is disposed on the side of the dielectric window away from the cavity. The chamber also includes the aforementioned Faraday shielding device, wherein a first shielding plate and a second shielding plate in the Faraday shielding device are located between the dielectric window and the radio frequency coil.

[0008] The technical solution adopted in this invention can achieve the following beneficial effects:

[0009] In the Faraday shielding device disclosed in this invention, as the etching depth of the wafer circuit pattern increases, the overlap between the first and second openings of the Faraday shielding device increases. As the overlap between the first and second openings increases, the aperture ratio of the Faraday shielding device increases, allowing more of the magnetic field generated by the RF coil to pass through. This results in more plasma being generated within the semiconductor process chamber, leading to higher wafer etching efficiency. Consequently, the increase in the depth of the wafer circuit pattern has a smaller impact on the width, thereby improving the aspect ratio of the wafer etching and enhancing the etching performance of the semiconductor process chamber, resulting in a higher wafer yield. Attached Figure Description

[0010] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings:

[0011] Figure 1 This is a cross-sectional view of a semiconductor process chamber disclosed in an embodiment of the present invention;

[0012] Figure 2 for Figure 1 A partial sectional view;

[0013] Figure 3 This is a schematic diagram of the drive mechanism and the first shielding plate of the Faraday shielding device disclosed in an embodiment of the present invention;

[0014] Figure 4 This is a schematic diagram of the structure of the second shielding plate of the Faraday shielding device disclosed in an embodiment of the present invention;

[0015] Figure 5 This is a schematic diagram showing the first and second openings of the Faraday shielding device disclosed in an embodiment of the present invention completely overlapping.

[0016] Figure 6 This is a schematic diagram showing the overlapping state of the first opening and the second opening of the Faraday shielding device disclosed in an embodiment of the present invention.

[0017] Explanation of reference numerals in the attached figures:

[0018] 100-cavity,

[0019] 200-RF coil,

[0020] 300 - Faraday shielding device; 310 - First shielding plate; 311 - First opening; 312 - First clearance hole; 320 - Second shielding plate; 321 - Second opening; 322 - Second clearance hole; 330 - Drive mechanism; 331 - Drive source; 332 - Connecting frame; 3321 - Connecting rod; 3322 - Adapter rod; 334 - Accommodation space.

[0021] 400 - Media Window. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0023] The technical solutions disclosed in the various embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0024] In semiconductor manufacturing, wafers are etched within semiconductor process chambers. As the depth of the etched circuit pattern increases, the width of the pattern decreases, reducing the aspect ratio and often resulting in a "V"-shaped morphology. Related techniques increase the etching time per etch cycle to achieve a high aspect ratio. However, this method can lead to over-etching at the bottom of the circuit pattern in each etching cycle, causing the sidewalls to form a "scalloped" shape, which can negatively impact device performance.

[0025] like Figures 1-6 As shown, this embodiment of the invention discloses a Faraday shielding device 300, which is used to shield the electric field generated by the radio frequency coil 200 in a semiconductor process chamber. The disclosed Faraday shielding device 300 includes a first shielding plate 310, a second shielding plate 320, and a driving mechanism 330.

[0026] The first shielding plate 310 has a first opening 311 extending through its thickness direction, and the second shielding plate 320 has a second opening 321 extending through its thickness direction. A driving mechanism 330 is used to change the relative position between the first shielding plate 310 and the second shielding plate 320, thereby changing the overlap of the first opening 311 and the second opening 321. Optionally, the driving mechanism 330 can drive either the first shielding plate 310 or the second shielding plate 320 to move; this is not limited herein. The first shielding plate 310 and the second shielding plate 320 can be stacked and movably connected.

[0027] Compared to manually changing the relative position between the first shielding plate 310 and the second shielding plate 320, using the drive mechanism 330 to drive the first shielding plate 310 offers higher precision, thus improving the etching accuracy of the wafer. Furthermore, the drive mechanism 330's movement of the first shielding plate 310 or the second shielding plate 320 prevents operators from directly contacting them, thereby avoiding electric shock and ensuring operator safety.

[0028] Optionally, the drive mechanism 330 can be a drive motor, cylinder, hydraulic cylinder, or other power structure, and of course, it can also be other power structures, which are not limited in this article.

[0029] Projecting along the thickness direction of the first shielding plate 310, the overlap between the first opening 311 and the second opening 321 is maximized when the projected outline of the first opening 311 coincides with the projected outline of the second opening 321. The overlap is minimized when the projected outline of the first opening 311 is outside the projected outline of the second opening 321. A greater overlap between the first opening 311 and the second opening 321 indicates a larger aperture ratio of the Faraday shielding device 300. The aperture ratio refers to the ratio of the open portion of the Faraday shielding device 300 to the total portion of the Faraday device. A larger aperture ratio allows the magnetic field to pass through more parts, generating more plasma and resulting in faster etching efficiency.

[0030] The Faraday shielding device 300 disclosed in this application is used to shield the electric field generated by the radio frequency coil 200. If the electric field generated by the radio frequency coil 200 is not shielded, the electric field will affect the uniformity of the etching rate of the wafer. The principle of the Faraday shielding device 300 in shielding the electric field is that the propagation direction of the electric field in space is perpendicular to the direction of the first opening 311 on the Faraday shielding device 300. The electric field propagates to the Faraday shielding device 300 and is absorbed by the Faraday shielding device 300. The direction of magnetic field propagation is parallel to the Faraday shielding direction, so the magnetic field can propagate through the first opening 311 and the second opening 321.

[0031] In the embodiments disclosed in this application, as the etching depth of the wafer circuit pattern increases, the overlap between the first opening 311 and the second opening 321 of the Faraday shielding device 300 increases. With the increase in the overlap between the first opening 311 and the second opening 321, the aperture ratio of the Faraday shielding device 300 increases. More of the magnetic field generated by the RF coil 200 passes through, more plasma is generated in the semiconductor process chamber, and the wafer etching efficiency is higher. As a result, the increase in the depth of the wafer circuit pattern has a smaller impact on the width, thereby improving the aspect ratio of the wafer etching, improving the etching performance of the semiconductor process chamber, and promoting a higher wafer yield.

[0032] In addition, by increasing the etching efficiency of the wafer, the sidewalls of the circuit pattern are etched into a "scallop" shape, which would otherwise result from increasing the etching time within the cycle, thereby improving the device performance of the wafer.

[0033] In another alternative embodiment, the angle by which the drive mechanism 330 controls the first shielding plate 310 to rotate each time is equal to the included angle between the opposite sidewalls of the first opening divided by the total number of process cycles. In related technologies, the etching process includes an etching step and a deposition step, which alternate in a cycle. The etching step etches the wafer, while the deposition step deposits a protective film on the sidewalls of the etched image to make the sidewalls less susceptible to etching. A deposition step is performed after each etching step; therefore, one etching step and one deposition step constitute one process cycle. The total number of process cycles is the total number of etching and deposition step cycles.

[0034] Furthermore, there can be multiple first openings 311, which can be distributed circumferentially along the first shielding plate 310. Similarly, there can be multiple second openings 321, which can be distributed circumferentially along the second shielding plate 320. The first openings 311 and the second openings 321 can be configured in a one-to-one correspondence. In this scheme, the number of both first openings 311 and second openings 321 is multiple, thereby further increasing the aperture ratio of the Faraday shielding device 300 and thus improving the wafer etching efficiency.

[0035] In the above embodiments, the first shielding plate 310 and the second shielding plate 320 can move along the plane containing the first shielding plate 310, that is, the first shielding plate 310 can move horizontally relative to the second shielding plate 320. This solution requires reserving space for the movement of the first shielding plate 310, thus the first shielding plate 310 occupies a relatively large installation space. In another optional embodiment, the driving mechanism 330 is used to drive the first shielding plate 310 to rotate along its central axis to change the overlap between the first opening 311 and the second opening 321. In this case, the first shielding plate 310 occupies a smaller installation space, thereby making the Faraday shielding device 300 smaller in size.

[0036] In another alternative embodiment, both the first opening 311 and the second opening 321 can be strip-shaped structures. The first opening 311 can extend from the center of the first shielding plate 310 to the edge of the first shielding plate 310. The second opening 321 can extend from the center of the second shielding plate 320 to the edge of the second shielding plate 320.

[0037] Typically, the center of the first shielding plate 310 and the second shielding plate 320 corresponds to the center of the cavity 100 of the semiconductor process chamber. The first opening 311 and the second opening 321 extend from the center to the edge, thereby enabling the plasma at the center and edge positions within the cavity 100 to be relatively uniform, thus improving the etching uniformity of the semiconductor process chamber.

[0038] In another alternative embodiment, the width of the first opening 311 gradually increases in the direction extending from the center of the first shielding plate 310 to the edge of the first shielding plate 310; and the width of the second opening 321 gradually increases in the direction extending from the center of the second shielding plate 320 to the edge of the second shielding plate 320.

[0039] In this scheme, the plasma distribution at the center of the cavity 100 is greater, while the plasma distribution at the edge region is less. Therefore, the width of the first opening 311 and the width of the second opening 321 increase from the center to the edge, thereby increasing the opening ratio of the Faraday shielding device 300 near the edge. This allows the plasma quantity at the center and edge to be relatively balanced, further improving the etching uniformity of the semiconductor process cavity.

[0040] In the specific process, the total number of process cycles within the semiconductor process chamber can be 100. According to process requirements, the total rotation angle of the first shielding plate 310 is 15°, so the first shielding plate 310 rotates 0.15° in each process cycle. For example, when the semiconductor process chamber is in the 100th cycle, the total rotation angle of the first shielding plate 310 is 15°, and the first opening 311 and the second opening 321 completely overlap.

[0041] In one specific embodiment, on the first shielding plate 310 and the second shielding plate 320, the area ratio of the first opening 311 to its adjacent solid surface is 3:1, and the area ratio of the second opening 321 to its adjacent solid surface is also 3:1. This can be understood as the first opening 311 being three times the size of its adjacent solid surface, and the second opening 321 being three times the size of its adjacent solid surface. Therefore, during the first process cycle, the first opening 311 and the second opening 321 cannot be completely blocked; the solid surfaces partially block the openings. For example, during the first process cycle, the opening ratio is 50%, and during the 100th process cycle, the opening ratio increases to 75%.

[0042] Taking the first shielding plate 310 rotating a total angle of 15° and the process cycle totaling 100 times as an example: In the first process cycle, the solid areas on the first shielding plate 310 and the second shielding plate 320 do not overlap at all. The solid area of ​​the first shielding plate 310 blocks the second opening 321, but the second opening 321 is not completely blocked. The solid area of ​​the second shielding plate 320 blocks the first opening 311, but the first opening 311 is not completely blocked. At this time, the aperture ratio of the Faraday shielding device can be 50%. In the second process cycle, the solid areas of the first shielding plate 310 and the second shielding plate 320 overlap by 1%, and the aperture ratio increases by 0.25%, meaning that the aperture ratio is 50.25% in the second process cycle. In the 100th process cycle, the solid areas of the first shielding plate 310 and the second shielding plate 320 overlap by 100%, and the aperture ratio increases by 25%, reaching 75%.

[0043] This document discloses a specific driving mechanism 330. Of course, the driving mechanism 330 can also be other structures, which are not limited here. Specifically, the driving mechanism 330 may include a driving source 331 and a connecting frame 332. One end of the connecting frame 332 is connected to the first shielding plate 310, and the other end of the connecting frame 332 can be connected to the driving source 331. The driving source 331 can be located above the first shielding plate 310.

[0044] In this scheme, the first shielding plate 310 is connected to the driving source 331 through the connecting bracket 332, so that the first shielding plate 310 and the driving source 331 are less likely to have cross-current, thus making it less likely to cause a short circuit in the driving source 331.

[0045] In another optional embodiment, the connecting frame 332 may further include adapter rods 3322 and connecting rods 3321, with multiple adapter rods 3322 and multiple connecting rods 3321. One end of each connecting rod 3321 may be located at the edge of the first shielding plate 310 and distributed circumferentially around the first shielding plate 310. The other ends of each connecting rod 3321 are connected to one end of each adapter rod 3322, and the other ends of each adapter rod 3322 converge toward the center of the first shielding plate 310 and connect to each other to form a converging end. The driving source 331 is connected to the converging end.

[0046] In this scheme, multiple adapter rods 3322 and multiple connecting rods 3321 can evenly transmit the driving force of the drive source 331 to the edge of the first shielding plate 310, thus making the edge of the first shielding plate 310 more uniformly stressed, thereby improving the driving performance of the drive mechanism 330.

[0047] At this time, the multiple adapter rods 3322 and the multiple connecting rods 3321 form a frame structure, and the radio frequency coil 200 can be located in the accommodating space 334 of the frame structure. At this time, the radio frequency coil 200 can be placed in the accommodating space 334, thereby providing protection for the radio frequency coil 200.

[0048] In another alternative embodiment, the connecting rod 3321 and the first shielding plate 310 can be connected vertically, and the adapter rod 3322 and the connecting rod 3321 can be connected vertically. This connection method has a simple and compact structure and strong connection strength.

[0049] In another alternative embodiment, the outer contour of the first shielding plate 310 may be the same as that of the second shielding plate 320, and the outer contour of the first opening 311 may be the same as that of the second opening 321. In this solution, the outer dimensions of the first shielding plate 310 and the second shielding plate 320 are the same, thus making the structure of the Faraday shielding device 300 more compact.

[0050] Furthermore, the opening ratios of the first shielding plate 310 and the second shielding plate 320 are both greater than 50%. When the first opening 311 and the second opening 321 completely overlap, the opening ratio of the Faraday shielding device can be greater than 50%, thus giving the Faraday shielding device a large opening ratio.

[0051] Based on the Faraday shielding device 300 of any of the above embodiments of the present invention, the present invention also discloses a semiconductor process chamber, wherein the disclosed semiconductor process chamber has the Faraday shielding device 300 of any of the above embodiments. The semiconductor process chamber disclosed in the present invention further includes a cavity 100, a radio frequency coil 200, and a dielectric window 400. The dielectric window 400 is disposed on the top opening of the cavity 100, and the dielectric window 400 and the cavity 100 enclose an etching space, in which the wafer is etched. The radio frequency coil 200 is disposed on the side of the dielectric window 400 away from the cavity 100. The first shielding plate 310 and the second shielding plate 320 in the Faraday shielding device 300 are located between the dielectric window 400 and the radio frequency coil 200.

[0052] In this scheme, as the etching depth of the wafer circuit pattern increases, the overlap between the first opening 311 and the second opening 321 of the Faraday shielding device 300 increases. With the increase in the overlap between the first opening 311 and the second opening 321, the aperture ratio of the Faraday shielding device 300 increases. More of the magnetic field generated by the RF coil 200 passes through, and more plasma is generated in the semiconductor process chamber. The etching efficiency of the wafer is higher, so that the increase in the depth of the wafer circuit pattern has a smaller impact on the width, thereby improving the aspect ratio of the wafer etching, improving the etching performance of the semiconductor process chamber, and promoting a higher wafer yield.

[0053] In the specific operation process, after the etching step and the deposition step complete one alternating cycle, the drive mechanism 330 drives the first shielding plate 310 to rotate by a certain angle, thereby increasing the overlap between the first opening 311 and the second opening 321. After the drive mechanism 330 drives the first shielding plate 310 to rotate by a certain angle, the next alternating cycle of the etching step and the deposition step is performed.

[0054] In the above embodiment, the second shielding plate 320 can be fixed to the dielectric window 400 by screws. The screws can be made of resin or other insulating materials.

[0055] In another optional embodiment, the first shielding plate 310 may have a first clearance hole 312, and the second shielding plate 320 may have a second clearance hole 322. The first clearance hole 312 and the second clearance hole 322 may be arranged opposite to each other. The gas inlet pipe of the semiconductor process chamber can pass through the first clearance hole 312 and the second clearance hole 322 into the dielectric window 400, and the gas inlet pipe is used to introduce reactive gas into the semiconductor process chamber.

[0056] The above embodiments of the present invention focus on describing the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. For the sake of brevity, they will not be described in detail here.

[0057] The above description is merely an embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A control method for a Faraday shielding device, wherein the Faraday shielding device is used to shield the electric field generated by a radio frequency coil (200) in a semiconductor process chamber, characterized in that, The Faraday shielding device (300) includes a first shielding plate (310), a second shielding plate (320), and a driving mechanism (330). The first shielding plate (310) has a first opening (311) extending through its thickness direction, and the second shielding plate (320) has a second opening (321) extending through its thickness direction. The driving mechanism (330) is used to change the relative position between the first shielding plate (310) and the second shielding plate (320) to change the overlap between the first opening (311) and the second opening (321). The control method includes: The angle at which the drive mechanism (330) controls the first shield plate (310) to rotate each time is equal to the included angle between the opposite sidewalls of the first opening (311) divided by the total number of process cycles. The overlap between the first opening and the second opening increases with the increase of the number of process cycles. When the total number of process cycles is reached, the first opening (311) and the second opening (321) completely overlap.

2. The control method for the Faraday shielding device according to claim 1, characterized in that, The number of first openings (311) is multiple, and the multiple first openings (311) are distributed at intervals along the circumference of the first shielding plate (310). The number of second openings (321) is multiple, and the multiple second openings (321) are distributed at intervals along the circumference of the second shielding plate (320). The first openings (311) and the second openings (321) are arranged in a one-to-one correspondence. The driving mechanism (330) drives the first shielding plate (310) to rotate along its central axis to change the overlap of the first openings (311) and the second openings (321).

3. The control method for the Faraday shielding device according to claim 2, characterized in that, Both the first opening (311) and the second opening (321) are strip-shaped structures. The first opening (311) extends from the center of the first shielding plate (310) to the edge of the first shielding plate (310). The second opening (321) extends from the center of the second shielding plate (320) toward the edge of the second shielding plate (320).

4. The control method for the Faraday shielding device according to claim 3, characterized in that, The width of the first opening (311) gradually increases in the direction extending from the center of the first shielding plate (310) to the edge of the first shielding plate (310); The width of the second opening (321) gradually increases in the direction extending from the center of the second shielding plate (320) to the edge of the second shielding plate (320).

5. The control method for the Faraday shielding device according to claim 1, characterized in that, The outer contour of the first shielding plate (310) is the same as that of the second shielding plate (320), the outer contour of the first opening (311) is the same as that of the second opening (321), and the opening ratio of the first shielding plate (310) and the second shielding plate (320) is greater than 50%.

6. The control method for the Faraday shielding device according to claim 2, characterized in that, The drive mechanism (330) includes a drive source (331) and a connecting frame (332). One end of the connecting frame (332) is connected to the first shielding plate (310), and the other end of the connecting frame (332) is connected to the drive source (331). The drive source (331) is located above the first shielding plate (310).

7. The control method for the Faraday shielding device according to claim 6, characterized in that, The connecting frame (332) includes a converter rod (3322) and a connecting rod (3321), and there are multiple converter rods (3322) and multiple connecting rods (3321); One end of each of the multiple connecting rods (3321) is located at the edge of the first shielding plate (310) and is distributed at intervals along the circumference of the first shielding plate (310). The other ends of the multiple connecting rods (3321) are respectively connected to one end of each of the multiple adapter rods (3322). The other ends of the multiple adapter rods (3322) converge toward the center of the first shielding plate (310) and are connected to each other to form a converging end. The driving source (331) is connected to the converging end.

8. The control method for the Faraday shielding device according to claim 7, characterized in that, The connecting rod (3321) is perpendicularly connected to the first shielding plate (310), and the adapter rod (3322) is perpendicularly connected to the connecting rod (3321).

9. A semiconductor process chamber, comprising a cavity (100), a radio frequency coil (200), a dielectric window (400), and a Faraday shield (300), wherein the dielectric window (400) is disposed on an opening at the top of the cavity (100), and the radio frequency coil (200) is disposed on the side of the dielectric window (400) away from the cavity (100), characterized in that, The Faraday shielding device (300) includes a first shielding plate (310), a second shielding plate (320), and a driving mechanism (330); the first shielding plate (310) has a first opening (311) extending through its thickness direction, and the second shielding plate (320) has a second opening (321) extending through its thickness direction. The first shielding plate (310) and the second shielding plate (320) are located between the dielectric window (400) and the radio frequency coil (200); the driving mechanism (330) is used to change the relative position between the first shielding plate (310) and the second shielding plate (320) to change the overlap of the first opening (311) and the second opening (321); The first shielding plate (310) and the second shielding plate (320) in the Faraday shielding device (300) are located between the dielectric window (400) and the radio frequency coil (200); The Faraday shielding device (300) is used to perform the control method as described in claims 1-8.

Images