Microwave plasma etching apparatus with zoning control
By employing a partitioned structure design with dual microwave solid-state sources and coaxial waveguides, and adjustable scalable components, the problem of poor etching uniformity in large-size wafers was solved. This enabled independent control and optimization of plasma density in the wafer center and edge regions, thereby improving the etching effect.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HENAN ORIENTALMATERIALS CO LTD
- Filing Date
- 2026-03-06
- Publication Date
- 2026-06-02
AI Technical Summary
Large wafers suffer from poor etching uniformity, especially during plasma diffusion, where the plasma density at the wafer edge is significantly lower than that in the center, making it difficult to achieve the required etching uniformity.
A partitioned structure design with dual microwave solid-state sources and coaxial waveguides is adopted. The inner waveguide corresponds to the central region of the wafer, and the outer waveguide corresponds to the edge region. High-density plasma is generated separately. The vertical position of the inner flow guide is adjusted by a retractable component to adjust the plasma supply and optimize etching uniformity.
It improves the etching uniformity of large-size wafers and adapts to the etching needs of wafers of different sizes by independently controlling the plasma density in the center and edge regions, thereby improving the etching effect.
Smart Images
Figure CN122138631A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of semiconductor equipment technology, and more specifically to a microwave plasma etching apparatus with zoned control. Background Technology
[0002] Plasma etching technology utilizes the interaction between plasma and wafer surface materials in a vacuum environment to selectively remove material from specific areas, precisely replicating the pattern defined by photoresist on the thin film surface, thus providing a foundation for the formation of subsequent device structures.
[0003] Among various plasma etching equipment, the electron cyclotron resonance (ECR) etching machine based on microwave-excited plasma has the advantages of strong plasma activity, low-temperature processing characteristics, reduced thermal damage to wafer surface materials, and facilitates high-precision etching control.
[0004] The microwave signal generated by the microwave solid-state source is directionally transmitted to the interior of the reaction chamber through a waveguide structure. Electromagnetic coils are arranged around the reaction chamber. When electrons are in the electric field generated by the microwaves and the perpendicular magnetic field generated by the coils, they will cyclotronically rotate along a specific trajectory. When the microwave frequency is fixed at 2.45 GHz and the magnetic flux density reaches 875 Gs, electrons will undergo cyclotron resonance. At this point, the probability of collisions between electrons and gas molecules increases significantly, leading to efficient ionization and the generation of high-density plasma, providing sufficient active particles for the etching process.
[0005] Because there is a certain spatial distance between the plasma generation area and the wafer surface, active particles need to diffuse to reach the wafer surface to participate in the etching reaction. As the wafer diameter continues to increase, the problems of plasma attenuation and uneven distribution during diffusion become more and more obvious. Specifically, the plasma density in the wafer edge area is significantly lower than that in the central area, which directly makes it difficult to achieve the required global etching uniformity for large-size wafers. Summary of the Invention
[0006] The purpose of this invention is to provide a microwave plasma etching apparatus with zoned control to solve the technical problem of poor etching uniformity of large-size wafers mentioned in the background art.
[0007] According to one aspect of the present invention, a zone-controlled microwave plasma etching apparatus is provided, comprising:
[0008] The system comprises a first microwave solid-state source, a second microwave solid-state source, an inner waveguide and an outer waveguide arranged coaxially, an inner flow guide, an outer flow guide, and a retractable component.
[0009] The first microwave solid-state source transmits microwaves to the inner waveguide via a coaxial cable to generate a first plasma within the inner waveguide, and the second microwave solid-state source transmits microwaves to the outer waveguide via a coaxial cable to generate a second plasma in the annular region between the inner and outer waveguides.
[0010] The outer guide shroud is fixedly connected to the outer waveguide, and the inner guide shroud is sleeved on the outside of the inner waveguide. An adjustable clamping cavity is formed between the inner guide shroud and the outer guide shroud to guide the second plasma to diffuse towards the edge region of the wafer.
[0011] The retractable component is connected to the inner flow shield and driven to move in the vertical direction to adjust the volume inside the adjustable clamping cavity.
[0012] In one possible implementation, the inner shroud includes an upper cylindrical section and a lower semi-conical section, with the inner wall of the cylindrical section fitting against the outer wall of the inner waveguide; the outer shroud is semi-conical and integrally connected with the outer waveguide.
[0013] In one possible implementation, a first waveguide coaxial converter is provided above the inner waveguide, and a second waveguide coaxial converter is provided above the outer waveguide; wherein, one end of the first waveguide coaxial converter is connected to a first microwave solid-state source via a coaxial cable, and the other end is connected to the inner waveguide; one end of the second waveguide coaxial converter is connected to a second microwave solid-state source via a coaxial cable, and the other end is connected to the outer waveguide.
[0014] In one possible implementation, a telescopic component through-hole is provided above the outer waveguide, through which the telescopic component extends into the interior of the outer waveguide and connects with the inner flow guide.
[0015] In one possible implementation, the telescopic component includes a connecting rod and a linear motor. The connecting rod passes through a telescopic component through-hole on the outer waveguide and connects to the inner guide shield. The linear motor drives the inner guide shield to move vertically along the outer wall of the inner waveguide via the connecting rod.
[0016] In one possible implementation, the inner waveguide and the outer waveguide are each connected to an independent gas supply line, and each gas supply line is equipped with a gas flow controller.
[0017] In one possible implementation, the aforementioned partitioned microwave plasma etching apparatus further includes an electromagnetic coil located outside the reaction chamber to generate a magnetic field, causing electrons in the inner waveguide and annular region to undergo electron cyclotron resonance under the combined action of the microwave electric field and magnetic field, thereby generating high-density plasma.
[0018] In one possible implementation, the output power of the first microwave solid-state source and the second microwave solid-state source can be independently adjusted to control the density of the first plasma and the second plasma, respectively.
[0019] In one possible implementation, the semi-conical section at the bottom of the inner fairing is arranged coaxially with the outer fairing, and the inclination angles of their conical surfaces are the same.
[0020] In one possible implementation, vacuum sealing gaskets are provided at the connection points of the first waveguide coaxial converter, the second waveguide coaxial converter, and the corresponding coaxial cable and waveguide, and the sealing gaskets are made of fluororubber.
[0021] This invention provides a microwave plasma etching apparatus with zoned control, which has the following advantages:
[0022] The microwave plasma etching apparatus system with partitioned control provided by this invention firstly employs a partitioned structure design with dual microwave solid-state sources and coaxial waveguides. The inner waveguide corresponds to the wafer center region, and the outer waveguide corresponds to the edge region, each independently generating high-density plasma. This avoids the problem of low edge density caused by plasma diffusion attenuation, improving the overall etching uniformity of large-size wafers. Secondly, the plasma density in the wafer center and edge regions can be adjusted by regulating the microwave power and reactive gas flow rate of the inner and outer waveguides, further optimizing etching uniformity. Finally, the inner shroud can move vertically along the outer wall of the inner waveguide. By adjusting the height of the inner shroud in the vertical direction, the cavity volume between the inner and outer shrouds can be changed, allowing for adjustments to the plasma supply in the edge region as needed. This addresses dynamic uniformity deviations in wafers of different sizes or during the etching process, thereby improving the etching effect on large-size wafers. Attached Figure Description
[0023] The above and other objects, features, and advantages of exemplary embodiments of the present invention will become readily apparent upon reading the following detailed description with reference to the accompanying drawings. In the drawings, several embodiments of the invention are illustrated by way of example and not limitation, and like or corresponding reference numerals denote like or corresponding parts, wherein:
[0024] Figure 1 This is a schematic diagram of a partition-controlled microwave plasma etching apparatus according to an embodiment of the present invention.
[0025] Figure 2 This is a schematic diagram of another partition-controlled microwave plasma etching apparatus according to an embodiment of the present invention.
[0026] Figure 3 This is a schematic diagram of another partition-controlled microwave plasma etching apparatus according to an embodiment of the present invention.
[0027] Figure 4 This is a schematic diagram of another partition-controlled microwave plasma etching apparatus according to an embodiment of the present invention.
[0028] Explanation of reference numerals in the attached figures:
[0029] 11. First microwave solid-state source; 12. Second microwave solid-state source; 21. Inner waveguide; 211. First waveguide coaxial converter; 22. Outer waveguide; 221. Second waveguide coaxial converter; 222. Telescopic component through hole; 31. Inner flow guide; 31a. Cylindrical section; 31b. Semi-conical section; 32. Outer flow guide; 4. Telescopic component; 41. Connecting rod; 42. Linear motor; 42a. Mover; 42b. Stator; 5. Wafer; 6. Electromagnetic coil; 7. Reaction chamber; 81. First flow meter; 82. Second flow meter; 83. Gas supply chamber; 9. Upper protective housing. Detailed Implementation
[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Those skilled in the art should understand that the embodiments described below are only some, not all, of the embodiments disclosed. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.
[0031] To address the technical problem of poor etching uniformity in large-size wafers in existing technologies, this invention provides a microwave plasma etching apparatus with zoned control.
[0032] In this invention, a partitioned structure design using dual microwave solid-state sources and coaxial waveguides is employed. The inner waveguide corresponds to the wafer center region, and the outer waveguide corresponds to the edge region, each independently generating high-density plasma. This avoids the problem of low edge density caused by plasma diffusion attenuation, thus improving the overall etching uniformity of large-size wafers. Secondly, the plasma density in the wafer center and edge regions can be adjusted by regulating the microwave power and reactive gas flow rate of the inner and outer waveguides, further optimizing etching uniformity. Finally, the inner shroud can move vertically along the outer wall of the inner waveguide. By adjusting the height of the inner shroud in the vertical direction, the cavity volume between the inner and outer shrouds can be changed, allowing for adjustments to the plasma supply to the edge region as needed. This addresses dynamic uniformity deviations in wafers of different sizes or during the etching process, thereby improving the etching effect on large-size wafers.
[0033] After introducing the basic principles of the present invention, various non-limiting embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Any number of elements in the drawings is for illustrative purposes only and not for limitation, and any naming is for distinction only and has no limiting meaning.
[0034] The principles and spirit of the present invention will be explained in detail below with reference to several representative embodiments.
[0035] According to one aspect of the present invention, a microwave plasma etching apparatus with zoned control is provided, such as... Figure 1 As shown, it includes:
[0036] The system comprises a first microwave solid-state source 11, a second microwave solid-state source 12, an inner waveguide 21 and an outer waveguide 22 arranged coaxially, an inner flow guide 31, an outer flow guide 32, and a retractable component 4.
[0037] The first microwave solid-state source 11 transmits microwaves to the inner waveguide 21 via a coaxial cable to generate a first plasma within the inner waveguide 21, and the second microwave solid-state source 12 transmits microwaves to the outer waveguide 22 via a coaxial cable to generate a second plasma in the annular region between the inner waveguide 21 and the outer waveguide 11.
[0038] The outer guide shroud 32 is fixedly connected to the outer waveguide 22, and the inner guide shroud 31 is sleeved on the outside of the inner waveguide 21. An adjustable clamping cavity is formed between the inner guide shroud 31 and the outer guide shroud 32 to guide the second plasma to diffuse towards the edge region of the wafer 5.
[0039] The aforementioned retractable component 4 is connected to the inner flow guide shroud 31 and driven to move in the vertical direction to adjust the volume inside the aforementioned adjustable clamping cavity.
[0040] It should be noted that both the first microwave solid-state source 11 and the second microwave solid-state source 12 operate at a frequency of 2.45 GHz. This frequency matches the 875 Gs magnetic flux density generated by the electromagnetic coil 7, satisfying the conditions for electron cyclotron resonance and ensuring the efficient ionization generation of the first and second plasmas.
[0041] Specifically, the first microwave solid-state source 11 transmits microwaves to the inner waveguide 21 via a coaxial cable, forming a stable electric field environment inside the inner waveguide 21. This environment, in conjunction with an external magnetic field, excites the first plasma, which is specifically responsible for etching the central region of the wafer 5. The second microwave solid-state source 12 transmits microwaves to the outer waveguide 22 via another coaxial cable, exciting the second plasma in the annular region between the inner and outer waveguides to enhance the etching uniformity of the edge region of the wafer 5.
[0042] In one possible implementation, the inner flow guide 31 includes an upper cylindrical section 31a and a lower semi-conical section 31b, with the inner wall of the cylindrical section 31a fitting against the outer wall of the inner waveguide.
[0043] In one possible implementation, the outer shroud 32 is semi-conical and integrally connected with the outer waveguide 22.
[0044] It should be noted that the outer guide shroud 32 adopts a semi-conical structure and is fixedly connected to the outer waveguide 22. For example, the outer guide shroud 32 can be bolted or welded to the outer waveguide 22 to form an integral unit. The adjustable clamping cavity formed between the semi-conical section 31b of the inner guide shroud 31 and the outer guide shroud 32 can guide the second plasma to diffuse along a preset trajectory to the edge region of the wafer 5. The inner guide shroud 31 adopts a composite structure with an upper cylindrical shape and a lower semi-conical shape. It is assembled to the outside of the inner waveguide 21 by a sleeve, and the inner wall of the upper cylindrical section 31a is tightly fitted to the outer wall of the inner waveguide 21.
[0045] It is understandable that the telescopic component 4 is an adjustable mechanism. The telescopic component 4 is directly connected to the inner guide shroud 31. By driving the inner guide shroud to move in the vertical direction, the internal volume of the adjustable clamping cavity can be changed in real time.
[0046] Specifically, for example, see Figure 2 When the retractable component 4 drives the inner guide shroud 31 to move upward, the volume of the adjustable clamping cavity formed between the lower semi-conical section 31b in the inner guide shroud 31 and the outer guide shroud 32 decreases, the transmission channel of the second plasma narrows, and the plasma flow rate diffused to the edge of the wafer 5 decreases accordingly. This is suitable for scenarios where the etching rate at the edge of the wafer is slightly higher than that at the center, and uniformity compensation can be achieved by reducing the supply of plasma at the edge.
[0047] For example, see also Figure 3 When the retractable component 4 drives the inner guide shroud 31 to move downward, the volume of the adjustable clamping cavity formed between the lower semi-conical section 31b of the inner guide shroud 31 and the outer guide shroud 32 increases, thereby widening the transmission channel of the second plasma and increasing the flow rate of the second plasma. This effectively compensates for the problem of severe plasma attenuation at the edge of large-size wafers and improves the edge etching rate.
[0048] In the above embodiments, the mechanical adjustment method of changing the adjustable clamping cavity by driving the inner guide shroud 31 to move vertically through the retractable component 4 can quickly adjust the diffusion flow rate of the second plasma and can be adapted to large-size wafers of different diameters.
[0049] See Figure 4 , Figure 4 A partial top view of the above-mentioned device, such as... Figure 4 As shown, a telescopic component through hole 222 is provided above the outer waveguide 22. The telescopic component 4 extends into the outer waveguide 12 through the telescopic component through hole 222 and is connected to the inner guide shroud 21.
[0050] See Figures 1 to 4In one possible implementation, the retractable component 4 includes a connecting rod 41 and a linear motor 42. The connecting rod 41 passes through the telescopic component through hole 222 provided on the outer waveguide 22 and is connected to the inner flow guide 31. The linear motor 42 drives the inner flow guide 31 to move vertically along the outer wall of the inner waveguide 21 through the connecting rod 41.
[0051] It is understandable that the aforementioned retractable component 4 achieves precise vertical drive of the inner guide shield 31 through the coordinated action of the linear motor 42 and the connecting rod 41.
[0052] Specifically, the connecting rod 41 passes through the telescopic component through hole 222 above the outer waveguide 22, with one end firmly connected to the inner guide shroud 31 and the other end connected to the linear motor 42; the linear motor 42 provides vertical driving force to the connecting rod 41, thereby driving the inner guide shroud 31 to move vertically along the outer wall of the inner waveguide 21 through the connecting rod 41.
[0053] In one possible implementation, the device further includes an upper protective housing 9, with the linear motor 42 fixedly mounted on the lower surface of the upper protective housing 9.
[0054] In one possible implementation, the linear motor 42 includes a mover 42a and a stator 42b, with the mover 42a fixedly connected to the connecting rod 41 and the stator 42b fixed to the lower surface of the upper protective housing 9.
[0055] In one possible implementation, the device further includes a telescopic component protective shell, which is a hollow cylindrical design that houses the portion of the linear motor 42 and the connecting rod 41 above the inner waveguide 21 and the outer waveguide 22. One end of the telescopic component protective shell is fixed to the lower surface of the upper protective shell 9, and the other end is fixedly connected to the upper surface of the outer waveguide 22.
[0056] It should be noted that the diameter of the hollow area inside the telescopic component protective shell is not less than the diameter of the telescopic component through hole 222, and the fixed connection between the telescopic component protective shell and the upper surface of the outer waveguide 22 completely includes the telescopic component through hole 222 to form a regional seal. The reaction gas overflowing from the telescopic component through hole 222 will be confined in the telescopic component protective shell and will not continue to diffuse outward, thus avoiding the destruction of the vacuum environment.
[0057] In one possible implementation, the device further includes an electromagnetic coil 6 disposed around the reaction chamber 7 to generate a magnetic field, causing electrons in the inner waveguide 21 and the annular region to undergo electron cyclotron resonance under the combined action of the microwave electric field and the magnetic field, thereby generating plasma.
[0058] See Figure 4 In one possible implementation, a first waveguide coaxial converter 211 is provided above the inner waveguide 21, and a second waveguide coaxial converter 221 is provided above the outer waveguide.
[0059] Among them, one end of the first waveguide coaxial 211 converter is connected to the first microwave solid-state source 11 via a coaxial cable, and the other end is connected to the inner waveguide 21.
[0060] One end of the aforementioned second waveguide coaxial converter 221 is connected to the aforementioned second microwave solid-state source 12 via a coaxial cable, and the other end is connected to the external waveguide 22.
[0061] In one possible implementation, the inner waveguide 21 and the outer waveguide 22 are each connected to an independent gas supply pipeline, and each of the gas supply pipelines is equipped with a gas flow controller (first flow meter 81, second flow meter 82).
[0062] In one possible implementation, the device further includes a gas supply chamber 83, which supplies gas to the inner waveguide 21 and the annular region between the inner waveguide 21 and the outer waveguide 22 via two gas supply pipelines. As mentioned above, a first flow meter 81 and a second flow meter 82 are respectively present in the two gas supply pipelines. By controlling the first flow meter 81, the flow rate of the reaction gas supplied from the gas supply chamber 83 to the inner waveguide 21 can be controlled. By controlling the second flow meter 82, the flow rate of the reaction gas supplied from the gas supply chamber 83 to the annular region between the inner waveguide 21 and the outer waveguide 22 can be controlled.
[0063] It is understood that, in the above embodiments, the flow rates of the reaction gas required for plasma generation can be adjusted separately through the independent gas supply paths of the inner waveguide 21 and the outer waveguide 22 and the corresponding gas flow meters (first flow meter 81 and second flow meter 82), providing an independent and controllable gas environment for the etching process in different regions.
[0064] In one possible implementation, the output power of the first microwave solid-state source 11 and the second microwave solid-state source 12 can be independently adjusted to control the density of the first plasma and the second plasma, respectively.
[0065] In one possible implementation, the semi-conical section at the lower part of the inner fairing 21 is arranged coaxially with the outer fairing 22, and the inclination angles of their conical surfaces are the same.
[0066] In one possible implementation, the connection points of the first waveguide coaxial converter 211, the second waveguide coaxial converter 221 and the corresponding coaxial cable and waveguide (inner waveguide 21, outer waveguide 22) are all provided with vacuum sealing gaskets, and the sealing gaskets are made of fluororubber.
[0067] In the above embodiments, firstly, the partitioned microwave plasma etching apparatus adopts a partitioned structure design with dual microwave solid-state sources and coaxial waveguides. The inner waveguide corresponds to the wafer center region, and the outer waveguide corresponds to the edge region, each independently generating high-density plasma. This avoids the problem of low edge density caused by plasma diffusion attenuation, improving the overall etching uniformity of large-size wafers. Secondly, the plasma density in the wafer center and edge regions can be adjusted by regulating the microwave power and reactive gas flow rate of the inner and outer waveguides, further optimizing etching uniformity. Finally, the inner shroud can move vertically along the outer wall of the inner waveguide. By adjusting the height of the inner shroud in the vertical direction, the cavity volume between the inner and outer shrouds can be changed, increasing or decreasing the plasma supply to the edge region as needed to address dynamic uniformity deviations in wafers of different sizes or during the etching process, thereby improving the etching effect on large-size wafers. This solves the technical problem of poor uniformity control in the etching process of large-size wafers using microwave-excited plasma methods in the prior art.
[0068] The above-described preferred embodiments of the present invention are provided as examples, but it will be apparent to those skilled in the art that such embodiments are provided merely by way of example. Many modifications, alterations, and alternatives will occur to those skilled in the art without departing from the spirit and intent of the invention. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in the practice of the invention. The appended claims are intended to define the scope of protection of the invention and therefore cover the modular compositions, equivalents, or alternatives within the scope of these claims.
Claims
1. A microwave plasma etching apparatus with zoned control, characterized in that, include: The system comprises a first microwave solid-state source, a second microwave solid-state source, an inner waveguide and an outer waveguide arranged coaxially, an inner flow guide, an outer flow guide, and a retractable component. Wherein, the first microwave solid-state source transmits microwaves to the inner waveguide via a coaxial cable to generate a first plasma within the inner waveguide, and the second microwave solid-state source transmits microwaves to the outer waveguide via a coaxial cable to generate a second plasma in the annular region between the inner and outer waveguides. The outer flow guide is fixedly connected to the outer waveguide, and the inner flow guide is sleeved on the outside of the inner waveguide. An adjustable clamping cavity is formed between the inner flow guide and the outer flow guide to guide the second plasma to diffuse towards the wafer edge region. The retractable component is connected to the inner flow guide and is driven to move in the vertical direction to adjust the volume inside the adjustable clamping cavity.
2. The apparatus according to claim 1, characterized in that: The inner flow guide includes an upper cylindrical section and a lower semi-conical section, with the inner wall of the cylindrical section fitting against the outer wall of the inner waveguide. The outer flow guide is semi-conical and integrally connected with the outer waveguide.
3. The apparatus according to claim 2, characterized in that: A first waveguide coaxial converter is provided above the inner waveguide, and a second waveguide coaxial converter is provided above the outer waveguide; The first waveguide coaxial converter is connected to the first microwave solid-state source at one end via a coaxial cable, and to the inner waveguide at the other end. One end of the second waveguide coaxial converter is connected to the second microwave solid-state source via a coaxial cable, and the other end is connected to the external waveguide.
4. The apparatus according to claim 1, characterized in that: The outer waveguide has a telescopic component through hole at the top, and the telescopic component extends into the interior of the outer waveguide through the telescopic component through hole and is connected to the inner flow guide shroud.
5. The apparatus according to claim 4, characterized in that: The telescopic component includes a connecting rod and a linear motor. The connecting rod passes through the telescopic component through hole provided on the outer waveguide and is connected to the inner flow guide. The linear motor drives the inner flow guide to move vertically along the outer wall of the inner waveguide through the connecting rod.
6. The apparatus according to claim 1, characterized in that: The inner waveguide and the outer waveguide are each connected to an independent gas supply pipeline, and each gas supply pipeline is equipped with a gas flow controller.
7. The apparatus according to claim 1, characterized in that: The device also includes an electromagnetic coil located outside the reaction chamber to generate a magnetic field, causing electrons in the inner waveguide and the annular region to undergo electron cyclotron resonance under the combined action of the microwave electric field and the magnetic field, thereby generating plasma.
8. The apparatus according to claim 1, characterized in that: The output power of the first microwave solid-state source and the second microwave solid-state source can be adjusted independently to control the density of the first plasma and the second plasma, respectively.
9. The apparatus according to claim 2, characterized in that: The semi-conical section at the bottom of the inner fairing is coaxially arranged with the outer fairing, and the inclination angles of their conical surfaces are the same.
10. The apparatus according to claim 3, characterized in that: Vacuum sealing gaskets are provided at the connection points of the first waveguide coaxial converter, the second waveguide coaxial converter and the corresponding coaxial cable and waveguide, and the sealing gaskets are made of fluororubber.