A plasma processing apparatus for semiconductor substrates

Abstract

The application relates to the technical field of wafer processing equipment, in particular to a plasma processing equipment for semiconductor substrates, which comprises a plasma traction part, a plasma generating part and a concentration balancing part; the plasma traction part forms an axial electric field above the substrate body after being connected with a first power supply; the plasma generating part generates plasma; and the concentration balancing part is arranged outside an etching chamber to increase the plasma concentration of the central region or the edge region; the application effectively improves the uniformity of the global plasma distribution of the substrate body, fundamentally solves the core defects that the plasma density and ion energy are difficult to be cooperatively controlled and the concentration distribution is uneven in the existing etching equipment, adapts to the high-precision etching demand of 7nm and below advanced process masks, and significantly improves the chip preparation yield.

Description

Technical Field

[0001] This invention relates to the field of wafer processing equipment technology, and more particularly to a plasma processing device for semiconductor substrates. Background Technology

[0002] In semiconductor photolithography, the photomask serves as the master for pattern transfer, and its etching precision directly determines the yield of chips in advanced processes of 7nm and below. However, existing mainstream reactive ion etching equipment has an inherent defect of interference from plasma density and ion energy coupling: the conventional capacitively coupled plasma density is difficult to exceed 10. 10 cm -3 The large scale leads to insufficient etching rate. Simply increasing the RF power will cause excessive ion energy, resulting in damage to the chromium layer of the mask and excessive line edge roughness. Furthermore, the plasma is prone to density gradient differences between the center and the edge due to edge effects in the cavity, leading to deterioration of the uniformity of critical dimensions. Summary of the Invention

[0003] This invention relates to a plasma processing device for semiconductor substrates, aiming to solve the problems of plasma density and ion energy coupling interference and uneven plasma concentration distribution in the etching chamber in existing etching equipment.

[0004] To achieve the above objectives, the present invention provides a plasma processing apparatus for semiconductor substrates, comprising: A plasma traction device is disposed in an etching chamber and its top is used to support the substrate body. After the plasma traction device is connected to a first power supply, it forms an axially extending electric field above the substrate body. A plasma generator is disposed in the etching chamber and located above the plasma traction device to generate plasma above the substrate body after process gas is introduced and a second power supply is turned on, and the plasma moves axially toward the substrate body under the action of the axially extending electric field. A concentration balancing element is disposed outside the etching chamber to generate an axially extending magnetic field after being connected to a third power source. The axially extending magnetic field causes the plasma to accelerate towards the central or edge region of the substrate body, thereby increasing the plasma concentration in the central or edge region and balancing the plasma concentration throughout the entire substrate body.

[0005] Optionally, the plasma processing apparatus for semiconductor substrates further includes a plasma gate, which is disposed in the etching chamber and between the plasma generator and the plasma traction unit. The plasma gate is provided with a second guide channel corresponding to the central region of the substrate body and capable of guiding plasma to the central region, and a first guide channel corresponding to the edge region of the substrate body and capable of guiding plasma to the edge region, so as to block crosstalk between plasmas moving towards the central region and the edge region by providing independent first and second guide channels.

[0006] Optionally, the plasma generator includes an induction coil, a gas pipe, and a gas spraying device; The gas pipe is fixedly inserted into the top of the etching chamber, and its inlet end is connected to the gas source. The gas spray component is fixed in the etching chamber and has several gas guides that are separated from each other and whose inlets are located on their circumferential sidewalls. Each gas guide extends from the circumferential sidewall of the gas spray component toward the center position, and its inlet end is connected to the outlet end of the gas pipe. The induction coil is located on the outer top wall of the etching chamber so that, after being connected to the second power supply, it can break down the process gas introduced from the gas pipe into the gas guide into plasma.

[0007] Optionally, the plasma gate is attached to the bottom of the gas sprayer, and the plasma gate includes a first sub-gate, a second sub-gate, and a third sub-gate; The first sub-selection section is arranged around the outside of the second sub-selection section, and there is a preset radial distance between the inner ring wall of the first sub-selection section and the inner sidewall of the etching chamber; the orthographic projection structure of the second sub-selection section on the inner top wall of the etching chamber covers the orthographic projection structure of the edge region on the inner top wall of the etching chamber; the first guide is arranged in the second sub-selection section and communicates with the gas guide; The second sub-selection section is arranged around the outside of the third sub-selection section. The area of ​​the orthographic projection structure of the third sub-selection section on the inner top wall of the etching chamber is the same as the area of ​​the orthographic projection structure of the central region on the inner top wall of the etching chamber. The second guide is arranged in the third sub-selection section and communicates with the gas guide.

[0008] Optionally, the magnetic field generated by the concentration balancing element, extending axially, acts on the central region; Both the second guide channel and the first guide channel are provided in multiples, and the number of the second guide channels is less than the number of the first guide channels. The aperture of each second guide channel is the same as the aperture of each first guide channel. Alternatively, the number of the second guide channel and the first guide channel may be the same, and the aperture of the second guide channel may be smaller than the aperture of the first guide channel.

[0009] Optionally, a plurality of concentration balancing elements are provided, and the magnetic fields generated by the plurality of concentration balancing elements extending along the axial direction act on the circumferentially connected segments of the edge region respectively. Both the second guide channel and the first guide channel are provided in multiples, and the number of the second guide channels is greater than the number of the first guide channels. The aperture of each second guide channel is the same as the aperture of each first guide channel. Alternatively, the number of the second guide channel and the first guide channel may be the same, and the aperture of the second guide channel may be larger than the aperture of the first guide channel.

[0010] Optionally, the plasma processing equipment for the semiconductor substrate further includes a radial drive connected to the concentration balancing member; the radial drive is used to drive the concentration balancing member to perform radial movement, so as to adjust the position of the axially extending magnetic field acting on the central region.

[0011] Optionally, the plasma processing equipment for the semiconductor substrate further includes a plurality of circumferential driving elements, each of which is connected to each of the concentration balancing elements in a one-to-one correspondence. Each of the circumferential driving elements is used to drive each of the concentration balancing elements to perform circumferential movement, so as to adjust the circumferential position of the magnetic field extending along the axial direction acting on each segment of the edge region.

[0012] Optionally, the plasma traction device includes a ceramic patch, a lower electrode, and a cooling section connected sequentially downward along the axial direction; the top of the ceramic patch supports the substrate body; after the lower electrode is connected to the first power source, it generates an electric field that extends axially and penetrates the ceramic patch.

[0013] Optionally, the plasma processing equipment for semiconductor substrates further includes a concentration detection device, an etching degree detection device, and a control module; The concentration detection device is disposed in the etching chamber, with its detection end facing upwards of the substrate body, for detecting the plasma concentration above the substrate body; the etching degree detection device is disposed in the etching chamber, with its detection end facing upwards of the upper surface of the substrate body, for detecting the etching degree of the substrate body. The first power supply, the second power supply, the third power supply, the gas source, the concentration detection device, and the etching degree detection device are all connected to the control module; the control module controls the first power supply, the second power supply, the gas source, and the third power supply according to the plasma concentration information detected by the concentration detection device and / or the etching degree information of the substrate body detected by the etching degree detection device.

[0014] Optionally, the plasma processing equipment for semiconductor substrates further includes a pin drive and a plurality of pins; The plasma traction component is provided with a plurality of movable holes arranged at intervals along the circumferential direction through the axial direction; each of the ejector pins is movably disposed in the movable holes in a corresponding manner. The driving end of the ejector pin drive is connected to the ejector pin to drive the ejector pin to move up and down along the axial direction.

[0015] Optionally, the end faces of the non-working areas of the etching chamber, the plasma traction device, and the plasma generator that come into contact with the plasma are all coated with an oxide layer or a plasma spray coating.

[0016] The beneficial effects of this invention are as follows: This invention uses a plasma traction device to form an independent axial electric field above the substrate, decoupling plasma generation from ion traction acceleration. This allows for an increase in etching rate by improving the second power supply, overcoming the capacitive coupling plasma density bottleneck, without simultaneously increasing ion energy. This avoids damage to the chromium layer of the mask and excessive line edge roughness caused by high-energy ions. Simultaneously, the axial magnetic field generated by the surrounding concentration balancing device actively controls the plasma to accelerate its accumulation towards the center or edge regions, specifically compensating for plasma concentration gradient differences caused by edge effects within the etching chamber. This effectively improves the uniformity of plasma distribution across the entire substrate, fundamentally solving the core defects of existing etching equipment, such as the difficulty in coordinating plasma density and ion energy control and uneven concentration distribution. It is suitable for the high-precision etching requirements of masks in advanced processes of 7nm and below, significantly improving chip fabrication yield. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a plasma processing apparatus for a semiconductor substrate in some embodiments of the present invention; Figure 2 for Figure 1 The diagram shows the structure of the gas spray component.

[0018] Explanation of reference numerals in the attached figures: 1. Etching chamber; 2. Plasma generator; 21. Induction coil; 22. Gas pipe; 23. Gas spraying device; 231. Gas guide channel; 3. Plasma traction device; 31. Lower electrode; 32. Cooling section; 33. Ceramic patch; 4. Concentration balancing device; 5. Concentration detection device; 6. Etching degree detection device; 7. Ejector pin device; 8. Ejector pin driving device; 9. Plasma gate device; 91. First sub-gate device; 92. Second sub-gate device; 921. First guide channel; 93. Third sub-gate device; 931. Second guide channel; 10. First power supply; 11. Second power supply. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention. Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by those skilled in the art. The terms "comprising" and similar expressions used herein mean that the element or object preceding the word covers the element or object listed following the word and its equivalents, but do not exclude other elements or objects.

[0020] This invention relates to a plasma processing device for semiconductor substrates, aiming to solve the problems of plasma density and ion energy coupling interference and uneven plasma concentration distribution in the etching chamber in existing etching equipment.

[0021] To address the problems existing in the prior art, embodiments of the present invention provide a plasma processing apparatus for semiconductor substrates, such as... Figure 1 As shown, the plasma processing equipment for semiconductor substrates includes a plasma traction unit 3, a plasma generator 2, and a concentration balancing unit 4.

[0022] In some embodiments, such as Figure 1 As shown, the plasma traction device 3 is disposed in the etching chamber 1 and its top is used to support the substrate body (e.g., the substrate body, but not limited to a mask or wafer). After the plasma traction device 3 is connected to the first power supply 10, an electric field extending along the axial direction (hereinafter referred to as the axial electric field) is formed above the substrate body.

[0023] Integrating the substrate body support and axial electric field generation functions into one not only simplifies the internal structural layout of the etching chamber 1 and reduces the interference of redundant components on the plasma flow field, but also utilizes the characteristic that the axial electric field is perpendicular to the substrate body surface to ensure that charged ions (plasma) are accelerated and bombarded in a direction perpendicular to the substrate body, avoiding problems such as pattern linewidth deviation and sidewall steepness degradation caused by oblique incidence. At the same time, the electric field coverage area is precisely matched with the substrate body support area, which can ensure uniform ion energy distribution throughout the substrate body, providing a core guarantee for the etching accuracy and uniformity of precision substrate bodies such as masks and wafers. It also facilitates the independent control of ion energy by adjusting the parameters of the first power supply 10, realizing decoupled control with plasma density.

[0024] The first power supply 10 includes, but is not limited to, an RF power supply or a DC power supply. When an RF power supply is selected, it can flexibly match the power range of 0~1000W and can stably generate a uniform axial electric field, which can meet the ion energy gradient control requirements of most etching processes. When a DC power supply is selected, it can provide a more stable constant potential difference and avoid noise interference caused by RF coupling. It is especially suitable for high-precision mask etching scenarios with extremely high requirements for ion energy consistency.

[0025] In some embodiments, such as Figure 1 As shown, the plasma generator 2 is disposed in the etching chamber 1 and located above the plasma traction member 3, so as to generate plasma above the substrate body after the process gas is introduced and the second power supply 11 is turned on, and the plasma moves axially toward the substrate body under the action of the axially extending electric field.

[0026] The second power supply 11 includes, but is not limited to, a radio frequency power supply, preferably an adjustable frequency band radio frequency source with a power of 0~5000W.

[0027] In some embodiments, such as Figure 1 As shown, the concentration balancing element 4 is arranged in a ring outside the etching chamber 1 to generate an axially extending magnetic field (hereinafter referred to as the axial magnetic field) after being connected to the third power supply. The axially extending magnetic field will cause the plasma to accelerate towards the central region or the edge region of the substrate body, thereby increasing the plasma concentration in the central region or the edge region, and thus balancing the plasma concentration in the entire substrate body.

[0028] This setup externalizes the magnetic field generating component, preventing the concentration balancing component 4 from being directly corroded by active particles due to plasma contact, and also preventing its metal material from being bombarded by plasma and generating impurities that contaminate the process environment. At the same time, through the Lorentz force of the axial magnetic field, the plasma can be actively targeted and controlled to gather in the central or edge regions where the concentration is low, accurately compensating for the concentration gradient difference caused by the inherent edge effect in the etching chamber 1. The plasma distribution across the entire substrate can be quickly balanced without adjusting the overall process parameters, fundamentally improving etching uniformity. In addition, the external structure facilitates later maintenance and replacement, reducing equipment operation and maintenance costs.

[0029] The third power source includes, but is not limited to, a DC power source, and may also be a low-frequency pulse power source. When it is working, it provides stable power to the concentration balancing element 4 which is arranged around the outer wall of the etching chamber 1, and can generate a uniform or non-uniform magnetic field that extends along the axial direction.

[0030] In some embodiments, such as Figure 1As shown, the plasma processing equipment for semiconductor substrates further includes a plasma gate 9, which is disposed in the etching chamber 1 and located between the plasma generator 2 and the plasma traction unit 3. The plasma gate 9 divides the etching chamber 1 into an upper plasma generator chamber and a lower plasma transport chamber.

[0031] In some embodiments, such as Figure 1 As shown, the plasma gate 9 is provided with a second guide channel 931 corresponding to the central region of the substrate body and capable of guiding plasma to the central region, and a first guide channel 921 corresponding to the edge region of the substrate body and capable of guiding plasma to the edge region. By providing independent first guide channels 921 and second guide channels 931, crosstalk between plasmas moving towards the central region and the edge region is blocked. The first guide channel 921 and the second guide channel 931 are preferably through holes.

[0032] This design avoids the upward diffusion of byproducts and sputtered particles generated during the etching process, which could contaminate core components such as the plasma generator 2. Furthermore, the first guide channel 921 and the second guide channel 931 independently guide the plasma flowing to the edge and center regions of the substrate body, respectively, blocking crosstalk between the two plasma paths and ensuring that the plasma flow fields in the center and edge regions do not interfere with each other. Simultaneously, this separation structure precisely limits the range of the axial electric field within the plasma transport cavity, preventing the axial electric field from extending upwards into the plasma generation cavity and interfering with the ionization process of the process gas. This further enhances the decoupling effect between plasma generation and ion traction, providing a stable flow field basis for subsequent concentration balance control.

[0033] In some embodiments, such as Figure 1 As shown, the plasma generator 2 includes an induction coil 21, a gas pipe 22, and a gas spraying device 23.

[0034] In some embodiments, such as Figure 1 As shown, the gas pipe 22 is fixedly inserted into the top of the etching chamber 1, with its inlet end connected to a gas source. The gas spray element 23 is fixed inside the etching chamber 1, and has several mutually spaced gas guide channels 231 with their inlets located on their circumferential sidewalls. Each gas guide channel 231 extends from the circumferential sidewall of the gas spray element 23 towards the center, and its inlet end is connected to the outlet end of the gas pipe 22. The induction coil 21 is located on the outer top wall of the etching chamber 1, so that after being connected to the second power supply 11, the process gas introduced from the gas pipe 22 into the gas guide channel 231 is broken down into plasma.

[0035] The structure of circumferential sidewall air intake combined with multiple sets of mutually isolated gas guide channels 231 not only avoids the problem of uneven gas distribution caused by traditional top center air intake, but also allows the process gas to diffuse smoothly from the circumferential sidewall to the center along the gas guide channel 231, forming a uniform planar airflow field below the gas spray component 23, ensuring the uniformity of plasma generation concentration throughout the entire area.

[0036] Meanwhile, the multi-point air intake on the circumferential sidewall, combined with the long-distance extension design of the gas guide 231, effectively prolongs the residence and premixing time of the process gas in the gas guide 231. This not only improves the energy coupling efficiency between gas molecules and the high-frequency magnetic field excited by the induction coil 21, reducing the threshold power of gas breakdown, but also slows down the process of gas breakdown into plasma. This precisely confines the ionization reaction within the gas guide 231, avoiding problems such as premature local breakdown and arc discharge caused by an excessively short air intake path. This further ensures the stability and uniformity of plasma generation, reduces damage to the core components in the etching chamber 1 caused by abnormal discharge, and extends the service life of the core components.

[0037] Of course, in other embodiments, the gas pipe 22 can also be fixedly inserted into the side wall of the etching chamber 1. The specific installation method can be flexibly adjusted according to the space of the process equipment, which will not be described in detail here.

[0038] In some embodiments, the structure of the plurality of gas channels 231 can be a series of bent channels arranged alternately around the circumference of the gas spray member 23 and staggered radially inward and outward. Multiple gas channels 231 extend interlaced within the spray member, without being interconnected, ultimately forming a maze-like layout in a plan view (e.g., ...). Figure 2 As shown in the figure, this structure significantly lengthens the flow path of the process gas, further extending the residence and premixing time of the gas in the spray element, enabling it to more fully absorb the magnetic field energy of the induction coil 21, reduce the breakdown threshold, and improve ionization efficiency.

[0039] Specifically, when the process starts, the second power supply 11 supplies power to the induction coil 21 on the outer top wall of the etching chamber 1, which generates a high-frequency alternating magnetic field. This magnetic field breaks down the process gas that is fully premixed and uniformly mixed in the labyrinth-shaped gas guide 231 and sent in through the gas pipe 22, generating high-density plasma below the gas spraying component 23. At the same time, the first power supply 10 supplies power to the plasma traction component 3 to form a vertically downward axial electric field. Under the action of this electric field, the plasma accelerates vertically towards the substrate body along the axial direction. After the concentration balancing component 4 located outside the chamber is connected to the third power supply, it generates an axial magnetic field. Under the action of the axial magnetic field, the plasma is transported to the region with low plasma concentration in the aforementioned central and edge regions, so that the plasma concentration in the central and edge regions tends to be consistent or the difference between the two plasma concentrations is negligible.

[0040] Of course, in other embodiments, the gas channels 231 can also be connected to each other. The specific connection method can be adjusted according to the actual process requirements, which will not be elaborated here.

[0041] In some embodiments, such as Figure 1 As shown, the plasma gate 9 is attached to the bottom of the gas spray member 23. The plasma gate 9 includes a first sub-gate section 91, a second sub-gate section 92, and a third sub-gate section 93. Preferably, the first sub-gate section 91 and the second sub-gate section 92 are both annular structures, and the third sub-gate section 93 is a disk-shaped structure.

[0042] It is worth noting that the gas guide 231 is recessed at the bottom of the gas spray member 23, and the groove of the gas guide 231 is in contact with the top of the plasma selector 9.

[0043] In some embodiments, such as Figure 1 As shown, the first sub-selection section 91 is arranged around the outside of the second sub-selection section 92. The first sub-selection section 91 preferably extends circumferentially and is fixed on the inner wall of the etching chamber 1. The inner ring wall of the first sub-selection section 91 and the inner wall of the etching chamber 1 have a preset radial distance (i.e., the radial width of the first sub-selection section 91). It is worth noting that the first sub-selection section 91 does not have a first guide channel 921 and a second guide channel 931.

[0044] In this embodiment, the radial width of the first sub-selection section 91 forms an annular gas buffer and retention area around the etching chamber 1. After the process gas flows out from the gas guide 231, it will first enter this area for secondary uniform diffusion, which invisibly prolongs the effective movement path and residence time of the gas in the cavity. This allows the gas molecules to have more time to absorb the magnetic field energy of the induction coil 21, reducing the breakdown threshold and improving ionization uniformity. It also helps to smooth out peaks and valleys through the flow stabilization effect of the buffer zone, eliminating flow rate fluctuations caused by the gas entering from the circumferential sidewall, and preventing the gas from escaping directly downward from the edge of the etching chamber 1 too early.

[0045] In some embodiments, such as Figure 1As shown, the orthographic projection structure of the second sub-selection section 92 on the inner top wall of the etching chamber 1 covers the orthographic projection structure of the edge region on the inner top wall of the etching chamber 1; the first guide channel 921 is disposed in the second sub-selection section 92 and communicates with the gas guide channel 231; the second sub-selection section 92 is arranged around the outside of the third sub-selection section 93, the area of ​​the orthographic projection structure of the third sub-selection section 93 on the inner top wall of the etching chamber 1 is the same as the area of ​​the orthographic projection structure of the central region on the inner top wall of the etching chamber 1, and the second guide channel 931 is disposed in the third sub-selection section 93 and communicates with the gas guide channel 231.

[0046] The partitioned design of the second sub-selection section 92 and the third sub-selection section 93 achieves physical isolation between the plasma flow fields of the edge region and the center region: the projection of the second sub-selection section 92 completely covers the edge region of the substrate, and its internal first guide channel 921 is precisely connected to the gas guide channel 231 to ensure that the edge region receives an independent and sufficient plasma supply; the projection of the third sub-selection section 93 is strictly matched with the area of ​​the center region, and its internal second guide channel 931 is independently connected to the corresponding gas guide channel 231 to avoid the gas supply to the center region being interfered with by the flow field of the edge region. This structure allows the first guide channel 921 and the second guide channel 931 to adapt to the plasma transport requirements of the edge region and the center region respectively. With the partitioned magnetic field control of the concentration balance component 4, it can specifically compensate for the concentration deviation in different regions. It also structurally blocks the crosstalk between the two plasma paths, ensuring the independence of the etching environment of the center region and the edge region, and greatly improving the control accuracy of the etching uniformity of the entire substrate body. It is especially suitable for the high-precision processing requirements of large-size wafers and photomasks.

[0047] In some embodiments, the axially extending magnetic field generated by the concentration balancing element 4 acts on the central region; both the second guide channel 931 and the first guide channel 921 are provided in plurality, and the number of second guide channels 931 is less than the number of first guide channels 921, and the aperture of each second guide channel 931 is the same as the aperture of each first guide channel 921. Alternatively, the number of second guide channels 931 and the first guide channel 921 is set to be the same, and the aperture of the second guide channel 931 is smaller than the aperture of the first guide channel 921. Both of these arrangements result in a higher plasma concentration in the edge region than in the central region.

[0048] This design takes advantage of the natural tendency of plasma to accumulate in the central region of the substrate body, by actively reducing the number of second channels 931 to decrease the initial plasma supply to the central region, thus avoiding the problem of excessively fast etching rate in the center from the physical source. At this time, the concentration balancing component 4 plays a role in "precise compensation": when fewer second channels 931 cause the plasma concentration in the central region to be lower than that in the edge region, the axial magnetic field generated by it can accelerate the plasma to the central region through the Lorentz force, thereby specifically making up for the concentration gap in the central region and achieving bidirectional synergistic control of "channel current limiting and magnetic field enrichment".

[0049] In some embodiments, a plurality of concentration balancing elements 4 are provided, and the axially extending magnetic fields generated by the plurality of concentration balancing elements 4 act on the circumferentially connected segments of the edge region respectively; a plurality of second guide channels 931 and first guide channels 921 are provided, and the number of second guide channels 931 is greater than the number of first guide channels 921, and the aperture of each second guide channel 931 is the same as the aperture of each first guide channel 921. Alternatively, the number of second guide channels 931 and first guide channels 921 is the same, and the aperture of the second guide channels 931 is larger than the aperture of the first guide channels 921. Both of these configurations result in a lower plasma concentration in the edge region than in the central region.

[0050] This setup addresses the pain point of uneven local concentration in the circumferential region of the edge area due to airflow disturbances and the asymmetry of the etching chamber 1 structure. It proactively increases the number of second guide channels 931 to enhance the initial plasma supply in the central region, providing sufficient "power source" for edge concentration control. At this point, the concentration balancing element 4 functions as "zoned targeted enrichment": multiple concentration balancing elements 4 are arranged in zones along the circumferential edge. Their respective axial magnetic fields do not cover the entire region but are precisely applied to corresponding sections. Using the Lorentz force, the plasma is drawn and concentrated towards the low-concentration zones at the edge (it is worth noting that this traction and concentration is all axial), specifically supplementing the concentration gaps at various points along the circumferential edge. This achieves coordinated control through "multiple guide channels ensuring supply and multiple magnetic poles for zoned enrichment." This avoids insufficient etching rate in the edge region due to excessively low initial concentration, and accurately corrects local deviations in the circumferential edge region without significant adjustments to overall process parameters. Only a relatively low-intensity zoned magnetic field is needed to achieve concentration balance across the entire edge region, significantly reducing the power load of a single concentration balancing element 4. In other words, the configuration of this embodiment can achieve a balance between plasma concentration in the central and peripheral regions, and can also adjust the balance of plasma concentration in each segment of the peripheral region.

[0051] Of course, in other embodiments, when the number and aperture of the first guide channel 921 and the second guide channel 931 are the same, the plasma concentration in the central region will be higher than that in the edge region due to the edge effect. Therefore, in order to make the plasma concentration regions in the central region and the edge region consistent, the axial magnetic field can be set to act on the edge region, which will not be elaborated here.

[0052] In some embodiments, the plasma processing apparatus for semiconductor substrates further includes a radial drive member connected to the concentration balancing member 4; the radial drive member is used to drive the concentration balancing member 4 to perform radial movement in order to adjust the position of the axially extending magnetic field acting on the central region.

[0053] This embodiment uses a radial drive to move the concentration balancing component 4 radially back and forth, dynamically adapting to the concentration deviation characteristics at different radial positions in the central region. Since the central region of the substrate is not an absolutely uniform field, density gradient differences often occur between the near-center and far-center regions due to airflow distribution and electric field edge effects. In this case, the target point of the axial magnetic field can be precisely moved by adjusting the radial position of the concentration balancing component 4. For example, if the density near the center is too high, the concentration balancing component 4 can be slightly adjusted outward, using the Lorentz force to pull more plasma axially towards the low-concentration region, thereby increasing the plasma concentration.

[0054] In some embodiments, the radial drive may be, but is not limited to, a ball screw module driven by a stepper motor, a piezoelectric ceramic micro-motion platform, or a pneumatic linear slide.

[0055] It is worth noting that, in other embodiments, the radial drive can drive the concentration balancer 4 to move along any radial line.

[0056] In some embodiments, the plasma processing apparatus for semiconductor substrates further includes a plurality of circumferential driving members, each of which is connected to each of the concentration balancing members 4 in a one-to-one correspondence. Each of the circumferential driving members is used to drive each of the concentration balancing members 4 to perform circumferential movement in order to adjust the circumferential position of each segment of the edge region by the axially extending magnetic field.

[0057] By linking each circumferential drive component with each concentration balancing component 4 in a one-to-one manner, the circumferential landing point of each axial magnetic field in the edge region can be precisely adjusted to adapt to the local concentration deviation characteristics of each edge segment. Due to the asymmetrical structure of the air inlet, exhaust outlet, observation window, etc. of the etching chamber 1, non-uniform concentration depressions may easily appear in the circumferential region of the edge region. At this time, there is no need to adjust the global process parameters. It is only necessary to drive the concentration balancing component 4 of the corresponding segment to move slightly in the circumferential direction to accurately align the target point of the axial magnetic field with the low concentration segment. The Lorentz force is used to target and guide the plasma to fill the concentration gap. This "regional independent circumferential adjustment" design not only solves the problem that fixed magnetic poles cannot adapt to the asymmetrical concentration distribution in the circumferential region of the edge region, but also avoids the flow field disturbance caused by the sweeping of a single magnetic pole over a wide range. It can achieve fine concentration compensation in the 360° full range of the edge region, and is especially suitable for the problem of uneven local etching in the edge region of large-size substrates due to the limitations of the chamber structure.

[0058] In some embodiments, the circumferential drive and the radial drive can be controlled by a separate control system, or they can be connected to a control module described later.

[0059] In some embodiments, the top of the etching chamber 1 is provided with several axially penetrating slits so that the high-frequency alternating magnetic field generated by the induction coil 21 can penetrate into the interior of the etching chamber 1 with low loss, while avoiding the metal top plate from directly cutting the magnetic field lines, which would generate eddy current loss and additional Joule heat. The slits are evenly distributed circumferentially and avoid the orthographic projection area of ​​the induction coil 21, which not only preserves the overall structural strength of the top plate, but also cuts off the annular eddy current path formed in the top plate, reduces the ineffective dissipation of radio frequency energy, and ensures that the magnetic field energy is concentrated and coupled to the gas spray component 23 at the top of the etching chamber 1, thereby improving the inductive coupling efficiency.

[0060] In some embodiments, such as Figure 1 As shown, the plasma traction device 3 includes a ceramic patch 33, a lower electrode 31, and a cooling section 32 connected sequentially downward along the axial direction; the top of the ceramic patch 33 supports the substrate body; after the lower electrode 31 is connected to the first power supply 10, it generates an electric field that extends axially and penetrates the ceramic patch 33.

[0061] In this embodiment, the ceramic patch 33 is made of dielectric materials such as high-purity alumina. It serves as the direct bearing surface of the substrate body, possessing excellent flatness and mechanical strength. Furthermore, its insulating properties block the direct conductive path between the lower electrode 31 and the substrate body, avoiding the risk of electrostatic breakdown. At the same time, it ensures that the axial electric field can penetrate to the top of the substrate body without distortion, preventing electric field shielding due to metal contact. The lower electrode 31 is made of good conductors such as aluminum alloy. After being connected to the first power supply 10, it can efficiently couple radio frequency energy, forming a uniform and stable axial electric field above the ceramic patch 33, providing a reliable electric field driving force for plasma directional traction. The cooling section 32 has a built-in circulating cooling channel, which can continuously remove the heat generated by the lower electrode 31 due to radio frequency loss and plasma irradiation during the etching process. This keeps the surface temperature of the ceramic patch 33 stably controlled between -20℃ and 80℃, avoiding critical dimensional deviations caused by deformation of the substrate body due to thermal stress, and preventing thermal decomposition of process gases or abnormal deposition of residues caused by high temperature. This ensures long-term consistency of etching accuracy from the perspective of thermal field stability.

[0062] Specifically, after the first power supply 10 is turned on, the lower electrode 31 forms a high-low potential with the inner top wall of the grounded (zero potential) etching chamber 1, thereby generating an axial electric field. The potential difference is uniformly distributed in the vertical direction, and the plasma accelerates along the axial direction perpendicularly to the upper surface of the substrate body under the action of the electric field force. By setting the high potential end on the lower electrode 31 and the low potential end on the inner top wall of the etching chamber 1 respectively, the electric field penetration efficiency can be guaranteed by the tight bonding between the lower electrode 31 and the ceramic patch 33.

[0063] In some embodiments, the plasma processing equipment for semiconductor substrates further includes a concentration detector 5, an etching degree detector 6, and a control module; the concentration detector 5 is disposed in the etching chamber 1, with its detection end facing upwards from the substrate body, for detecting the plasma concentration above the substrate body; the etching degree detector 6 is disposed in the etching chamber 1, with its detection end facing upwards from the upper surface of the substrate body, for detecting the etching degree of the substrate body; the first power supply 10, the second power supply 11, the third power supply, the gas source, the concentration detector 5, and the etching degree detector 6 are all connected to the control module; the control module controls the first power supply 10, the second power supply 11, the gas source, and the third power supply according to the plasma concentration information detected by the concentration detector 5 and / or the etching degree information of the substrate body detected by the etching degree detector 6.

[0064] This embodiment constructs a fully closed-loop intelligent control system encompassing "perception, decision-making, and execution." The concentration detection device 5 captures the full-domain distribution characteristics of plasma above the substrate in real time, and the etching rate detection device 6 monitors the etching process online. This provides the control module with dual-dimensional process feedback: on one hand, it can dynamically adjust the output of the third power supply based on real-time concentration data to correct the magnetic field strength, drive the radial and circumferential drive components, and fine-tune the position of the concentration balance device 4, accurately compensating for concentration deviations between the central and edge regions. On the other hand, it can synchronously and collaboratively control the power of the first power supply 10 (ion energy), the power of the second power supply 11 (plasma density), and the gas source flow rate in conjunction with etching rate feedback. This achieves optimized matching of ion energy, plasma concentration, and etching rate, avoiding process fluctuations caused by single-parameter control and responding promptly to changes in operating conditions such as airflow disturbances and consumable aging. It automatically maintains long-term stability of etching uniformity and precision without manual intervention, significantly reducing reliance on operator experience and significantly improving the etching yield and process repeatability of photomasks and large-size wafers in advanced processes.

[0065] In some embodiments, the concentration detection element 5, the etching degree detection element 6, and the control module can all be mature commercial standardized components. The concentration detection element 5 can be an optical emission spectrometer or a Langmuir probe array, the etching degree detection element 6 can be a laser interferometer or an endpoint detector, and the control module is built based on an industrial PLC or an embedded industrial control computer.

[0066] In some embodiments, such as Figure 1 As shown, the plasma processing equipment for semiconductor substrates further includes a pin drive 8 and a plurality of pins 7; the plasma traction member 3 has a plurality of movable holes arranged circumferentially through it along the axial direction; each pin 7 is correspondingly arranged with one of the movable holes, and each pin 7 is movably disposed within the movable hole; the driving end of the pin drive 8 is connected to the pin 7 to drive the pin 7 to move up and down along the axial direction. Preferably, the plurality of pins 7 are arranged at equal intervals.

[0067] This embodiment enables automated, non-destructive loading and unloading of the substrate body. Several ejector pins 7 are evenly distributed circumferentially in the non-working area of ​​the plasma traction unit 3. When picking up or placing the substrate body, the ejector pins 7 rise and pass through the movable hole to smoothly lift the substrate body, avoiding direct contact between the robot arm and the bearing surface, which could cause scratches on the ceramic patch 33 or contamination of the substrate body. During etching, the ejector pins 7 descend and retract into the movable hole, without affecting the bonding accuracy between the substrate body and the ceramic patch 33 or the uniformity of the axial electric field.

[0068] In some embodiments, one ejector pin driver 8 can be used to drive several ejector pins 7 to move up and down simultaneously, or several ejector pin drivers 8 can be provided, with each ejector pin driver 8 corresponding to each ejector pin 7.

[0069] In some embodiments, the end faces of the non-working areas of the etching chamber 1, the plasma traction device 3, and the plasma generator 2 that are in contact with the plasma are all coated with an oxide layer or a plasma spraying layer.

[0070] The non-working areas of the etching chamber 1, plasma traction device 3, and plasma generator 2 that come into contact with the plasma are all coated with an oxide layer or a plasma spray coating, which can provide multiple protections. This type of coating has high density and strong chemical inertness. It can not only block active particles in the plasma from etching the material of the equipment body and prevent metal impurities from falling off and contaminating the process environment, but also reduce the secondary electron emission coefficient of the wall of the etching chamber 1, reduce wall recombination loss, stabilize the distribution of the plasma sheath, and reduce the probability of adsorption of residues on the inner wall of the etching chamber 1, thus extending the cleaning cycle.

[0071] In some embodiments, the oxide layer or plasma spray coating layer may be ceramic materials such as yttrium oxide, aluminum oxide, or yttrium fluoride.

[0072] In some embodiments, the plasma processing equipment for semiconductor substrates includes, but is not limited to, plasma etching equipment, and can also be extended to plasma deposition equipment and photoresist removal equipment: In the deposition process, the axial magnetic field generated by the concentration balancing device can regulate the radial distribution of reactive particles and improve the global uniformity of film thickness; In the photoresist removal process, the structure can guide active plasma to cover the substrate surface more uniformly, improving the photoresist removal efficiency while avoiding local over-bombardment damage to the underlying material.

[0073] While embodiments of the present invention have been described in detail above, it will be apparent to those skilled in the art that various modifications and variations can be made to these embodiments. However, it should be understood that such modifications and variations fall within the scope and spirit of the present invention. Furthermore, the present invention described herein may have other embodiments and can be implemented or carried out in various ways.

Claims

1. A plasma processing apparatus for semiconductor substrates, characterized in that, include: A plasma traction device is disposed in an etching chamber and its top is used to support the substrate body. After the plasma traction device is connected to a first power supply, it forms an axially extending electric field above the substrate body. A plasma generator is disposed in the etching chamber and located above the plasma traction device to generate plasma above the substrate body after process gas is introduced and a second power supply is turned on, and the plasma moves axially toward the substrate body under the action of the axially extending electric field. A concentration balancing element is disposed outside the etching chamber to generate an axially extending magnetic field after being connected to a third power source. The axially extending magnetic field causes the plasma to accelerate towards the central or edge region of the substrate body, thereby increasing the plasma concentration in the central or edge region and balancing the plasma concentration throughout the entire substrate body.

2. The plasma processing apparatus for semiconductor substrates according to claim 1, characterized in that, It also includes a plasma gate, which is disposed in the etching chamber and between the plasma generator and the plasma traction unit. The plasma gate is provided with a second guide channel corresponding to the central region of the substrate body and capable of guiding the plasma to the central region, and a first guide channel corresponding to the edge region of the substrate body and capable of guiding the plasma to the edge region, so as to block crosstalk between the plasma moving to the central region and the edge region by providing independent first and second guide channels.

3. The plasma processing apparatus for semiconductor substrates according to claim 2, characterized in that, The plasma generator includes an induction coil, a gas pipe, and a gas spray device; The gas pipe is fixedly inserted into the top of the etching chamber, and its inlet end is connected to the gas source. The gas spray component is fixed in the etching chamber and has several gas guides that are separated from each other and whose inlets are located on their circumferential sidewalls. Each gas guide extends from the circumferential sidewall of the gas spray component toward the center position, and its inlet end is connected to the outlet end of the gas pipe. The induction coil is located on the outer top wall of the etching chamber so that, after being connected to the second power supply, it can break down the process gas introduced from the gas pipe into the gas guide into plasma.

4. The plasma processing apparatus for semiconductor substrates according to claim 3, characterized in that, The plasma gate is attached to the bottom of the gas sprayer, and the plasma gate includes a first sub-gate, a second sub-gate, and a third sub-gate. The first sub-selection section is arranged around the outside of the second sub-selection section, and there is a preset radial distance between the inner ring wall of the first sub-selection section and the inner sidewall of the etching chamber; the orthographic projection structure of the second sub-selection section on the inner top wall of the etching chamber covers the orthographic projection structure of the edge region on the inner top wall of the etching chamber; the first guide is arranged in the second sub-selection section and communicates with the gas guide; The second sub-selection section is arranged around the outside of the third sub-selection section. The area of ​​the orthographic projection structure of the third sub-selection section on the inner top wall of the etching chamber is the same as the area of ​​the orthographic projection structure of the central region on the inner top wall of the etching chamber. The second guide is arranged in the third sub-selection section and communicates with the gas guide.

5. The plasma processing apparatus for semiconductor substrates according to claim 4, characterized in that, The magnetic field generated by the concentration balancing element, extending axially, acts on the central region. Both the second guide channel and the first guide channel are provided in multiples, and the number of the second guide channels is less than the number of the first guide channels. The aperture of each second guide channel is the same as the aperture of each first guide channel. Alternatively, the number of the second guide channel and the first guide channel may be the same, and the aperture of the second guide channel may be smaller than the aperture of the first guide channel.

6. The plasma processing apparatus for semiconductor substrates according to claim 4, characterized in that, The concentration balancing element is provided in several parts, and the magnetic field generated by the concentration balancing element along the axial direction acts on the circumferentially connected sections of the edge region respectively. Both the second guide channel and the first guide channel are provided in multiples, and the number of the second guide channels is greater than the number of the first guide channels. The aperture of each second guide channel is the same as the aperture of each first guide channel. Alternatively, the number of the second guide channel and the first guide channel may be the same, and the aperture of the second guide channel may be larger than the aperture of the first guide channel.

7. The plasma processing apparatus for semiconductor substrates according to claim 5, characterized in that, It also includes a radial drive member connected to the concentration balancing member; the radial drive member is used to drive the concentration balancing member to make radial movements in order to adjust the position of the magnetic field extending along the axial direction acting on the central region.

8. The plasma processing apparatus for semiconductor substrates according to claim 6, characterized in that, It also includes several circumferential driving components, each of which is connected to each of the concentration balancing components in a one-to-one correspondence. Each of the circumferential driving components is used to drive each of the concentration balancing components to perform circumferential movement, so as to adjust the circumferential position of the magnetic field extending along the axial direction acting on each segment of the edge region.

9. The plasma processing apparatus for semiconductor substrates according to claim 1, characterized in that, The plasma traction device includes a ceramic patch, a lower electrode, and a cooling section connected sequentially downward along the axial direction; the top of the ceramic patch supports the substrate body; after the lower electrode is connected to the first power source, it generates an electric field that extends axially and penetrates the ceramic patch.

10. The plasma processing apparatus for semiconductor substrates according to claim 3, characterized in that, It also includes concentration detection components, etching detection components, and a control module; The concentration detection device is disposed in the etching chamber, with its detection end facing upwards of the substrate body, for detecting the plasma concentration above the substrate body; the etching degree detection device is disposed in the etching chamber, with its detection end facing upwards of the upper surface of the substrate body, for detecting the etching degree of the substrate body. The first power supply, the second power supply, the third power supply, the gas source, the concentration detection device, and the etching degree detection device are all connected to the control module; the control module controls the first power supply, the second power supply, the gas source, and the third power supply according to the plasma concentration information detected by the concentration detection device and / or the etching degree information of the substrate body detected by the etching degree detection device.

11. The plasma processing apparatus for semiconductor substrates according to claim 1, characterized in that, It also includes a ejector drive and several ejector pins; The plasma traction component is provided with a plurality of movable holes arranged at intervals along the circumferential direction through the axial direction; each of the ejector pins is movably disposed in the movable holes in a corresponding manner. The driving end of the ejector pin drive is connected to the ejector pin to drive the ejector pin to move up and down along the axial direction.

12. The plasma processing apparatus for semiconductor substrates according to claim 1, characterized in that, The non-working areas of the etching chamber, the plasma traction device, and the plasma generator that come into contact with the plasma are all coated with an oxide layer or a plasma spray coating.

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