Plasma processing apparatus and wafer processing method

Abstract

The embodiment of the invention provides a plasma processing device and a wafer processing method. The plasma processing device comprises a process chamber, a medium cylinder, a plasma generation unit, a base assembly, a main exhaust system and an auxiliary adsorption system, the main exhaust system is connected with the process chamber through a main exhaust pipeline and is used for adjusting the pressure in the process chamber; the auxiliary adsorption system is used for exhausting gas between the to-be-treated workpiece and the bearing surface before the main exhaust system works; the base assembly comprises a tray and a connecting rod for supporting the tray, the tray is provided with a bearing surface for bearing a to-be-treated workpiece, a plurality of adsorption holes are formed in the bearing surface, and air exhaust channels for communicating the adsorption holes with the auxiliary adsorption system are formed in the tray and the connecting rod; the auxiliary adsorption system comprises an auxiliary exhaust pipeline connected to the exhaust channel and a first valve arranged on the auxiliary exhaust pipeline. According to the technical scheme of the embodiment of the invention, the wafer can be effectively prevented from sliding due to the lateral force of the air flow in the technological process, and the stability and yield of the technology are ensured.

Description

Technical Field

[0001] This disclosure relates to the field of semiconductor manufacturing equipment technology, and in particular to a plasma processing apparatus and a wafer processing method. Background Technology

[0002] In semiconductor chip manufacturing, ICP (Inductively Coupled Plasma) etching and resist stripping equipment are critical process equipment. To reduce the bombardment damage to wafers by high-energy ions, remote plasma technology is widely used. This technology generates plasma in a region far from the wafer and uses a grid or baffle structure to filter out most charged ions, allowing only electrically neutral free radicals to reach the wafer surface. The highly reactive chemical properties of these free radicals react with the materials on the wafer surface, thus completing the etching or resist stripping process. In high-temperature processes (e.g., above 400°C), aluminum nitride (AlN) ceramics are often used as the material for heaters (trays) due to their excellent thermal conductivity and insulation. At conventional temperatures, aluminum alloys are also widely used due to their good machinability and cost advantages.

[0003] However, in actual manufacturing processes, residual gas often remains between the wafer and the heater after the wafer is placed on the heater surface. This gas forms an "air cushion" on the back of the wafer, causing it to be in a "suspended" or low-friction state. If the main extraction system is activated for high-flow extraction or pressure control, the airflow will generate a lateral drag force, causing the wafer to slide towards the extraction port, since the extraction port is usually located on the side or bottom of the chamber. This wafer sliding leads to poor process uniformity and can even cause wafer fragmentation or equipment failure. Summary of the Invention

[0004] This disclosure provides a plasma processing apparatus and a wafer processing method to solve or alleviate one or more technical problems in the prior art.

[0005] As one aspect of this disclosure, an embodiment provides a plasma processing apparatus, comprising: A process chamber that defines a reaction space; A medium cylinder, wherein a first end of the medium cylinder is connected to a cover plate and a second end is connected to the process chamber; A plasma generation unit is used to excite process gas within the dielectric cylinder to generate plasma. A tray is disposed within the process chamber, the tray having a bearing surface for bearing the workpiece to be processed; The main exhaust system, connected to the chamber via a main exhaust pipe, is used to regulate the pressure within the process chamber. An auxiliary adsorption system is used to discharge the gas between the workpiece to be treated and the bearing surface before the main exhaust system is activated; The bearing surface is provided with multiple adsorption holes, and the tray is provided with an air extraction channel that connects the adsorption holes and the auxiliary adsorption system.

[0006] In one embodiment, the auxiliary adsorption system includes an auxiliary exhaust pipe and a first valve disposed on the auxiliary exhaust pipe, the auxiliary exhaust pipe being connected to the extraction channel.

[0007] In one embodiment, the plurality of adsorption holes are circular holes, and the circular holes are arranged on the bearing surface to form concentric circles of at least one diameter.

[0008] In one embodiment, the plurality of adsorption holes are strip-shaped openings arranged in a straight line or arc along the plane of the bearing surface, and the plurality of strip openings are arranged to form at least one group of adsorption ports surrounding the center of the tray at the same distance.

[0009] In one embodiment, the diameter of the concentric circles or the distance between the adsorption port groups is determined according to the diameter of the workpiece to be processed.

[0010] In one embodiment, the device further includes a grid disposed at the connection between the medium cylinder and the chamber or inside the chamber, the grid being located between the region corresponding to the coil and the tray.

[0011] In one embodiment, the grid is provided with filter through-holes configured to filter ions in the plasma and allow free radicals to pass through.

[0012] In one embodiment, the tray is made of aluminum nitride ceramic or an aluminum alloy with an anodized surface.

[0013] In one embodiment, the main exhaust system includes: The second valve is installed on the main exhaust pipe; The connection port between the main exhaust pipe and the process chamber is located on the side or below the tray, and is used to laterally extract air from the process chamber.

[0014] In one possible implementation, the plasma generation unit includes: An RF coil is wound around the outer wall of the dielectric cylinder; A radio frequency (RF) power supply, electrically connected to the RF coil, is used to couple RF energy to the process gas inside the dielectric cylinder.

[0015] In one embodiment, the device further includes: An air intake unit is located at the top of the medium cylinder and is used to introduce process gas into the medium cylinder. A gas path control device is provided, wherein the main exhaust system, the auxiliary adsorption system, and the intake unit are all connected to the gas path control device; wherein the gas path control device is configured to supply gas to the intake unit and provide suction negative pressure for the main exhaust system and the auxiliary adsorption system.

[0016] As one aspect of this disclosure, this embodiment provides a wafer processing method using the aforementioned plasma processing apparatus, comprising: S1: Place the wafer on the support surface of the tray of the plasma processing device; S2: Open the first valve to connect the adsorption hole on the tray with the negative pressure source. Use the negative pressure source to extract the residual gas between the wafer and the support surface through the adsorption hole to eliminate the air cushion effect and make the wafer adhere to the support surface. S3: Close the first valve; S4: Open the second valve of the main exhaust system, use the negative pressure source to evacuate and control the pressure of the process chamber, and perform plasma treatment process.

[0017] The embodiments disclosed herein employ the above-described technical solution. By setting adsorption holes on the tray surface and coordinating with the operation sequence of the auxiliary adsorption system, the air cushion effect on the back of the wafer can be eliminated in advance before the main suction action begins, increasing the friction between the wafer and the tray. This effectively prevents the wafer from sliding due to the lateral force of airflow during the process, ensuring the stability and yield of the process.

[0018] The above overview is for illustrative purposes only and is not intended to be limiting in any way. Further aspects, embodiments, and features of this disclosure will become readily apparent from the accompanying drawings and the following detailed description, in addition to the illustrative aspects, embodiments, and features described above. Attached Figure Description

[0019] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the various drawings denote the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings depict only some embodiments provided according to this disclosure and should not be construed as limiting the scope of this disclosure.

[0020] Figure 1 A schematic diagram of the overall structure of a plasma processing apparatus according to an embodiment of the present disclosure is shown. Figure 2 A cross-sectional view of a base assembly according to an embodiment of the present disclosure is shown.

[0021] Explanation of reference numerals in the attached drawings: 1. Process chamber; 2. Base assembly; 21. Tray; 22. Connecting rod; 23. Adsorption hole; 24. Air extraction channel; 3. Main exhaust pipe; 4. Medium cylinder; 5. Inlet pipe; 6. Grille; 7. Wafer; 8. Auxiliary exhaust pipe; 9. Coil. Detailed Implementation

[0022] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of this disclosure. Therefore, the drawings and description are to be considered exemplary in nature and not restrictive.

[0023] Figure 1 A schematic diagram of a plasma processing apparatus according to an embodiment of the present disclosure is shown. Figure 1 As shown, the device includes: Process chamber 1, with an opening at its upper part, defines a reaction space for accommodating the workpiece to be processed; The dielectric cylinder 4 has its first axial end connected to the cover plate and its second end connected to the opening of the process chamber 1. The dielectric cylinder 4 is usually made of dielectric materials such as quartz or ceramic. A plasma generating unit is used to excite process gas in the dielectric cylinder 4 to generate plasma. The plasma generating unit includes a coil 9 wound around the outside of the dielectric cylinder 4. The base assembly 2, disposed in the process chamber 1, includes a tray 21 and a connecting rod 22 supporting the tray 21. The tray 21 has a bearing surface for bearing the workpiece (wafer 7) to be processed. The main exhaust system is connected to the process chamber 1 via the main exhaust pipe 3 and is used to regulate the pressure inside the process chamber (1); the main exhaust pipe 3 is connected to the bottom or side wall of the process chamber 1. as well as An auxiliary adsorption system is used to discharge the gas between the workpiece to be treated and the bearing surface before the main exhaust system is activated; The bearing surface is provided with a plurality of adsorption holes 23, and the tray 21 and the connecting rod 22 are provided with an air extraction channel that connects the adsorption holes 23 to the auxiliary adsorption system. The auxiliary adsorption system includes an auxiliary exhaust pipe 8 connected to the air extraction channel and a first valve provided on the auxiliary exhaust pipe 8.

[0024] In this embodiment, radio frequency energy is fed into the internal vacuum environment via the feed coil 9 and the dielectric cylinder 4, exciting the introduced process gas into plasma. To achieve remote plasma processing, a grid 6 is provided between the dielectric cylinder 4 and the wafer 7.

[0025] In one embodiment, a grid 6 is disposed at the opening of the process chamber 1, covering the opening. The grid 6 has a specific aperture ratio and aspect ratio, and its function is to filter out most of the charged ions in the plasma while allowing electrically neutral free radicals to pass through. In this way, the substances reaching the surface of the wafer 7 are mainly chemically active free radicals, which react with the photoresist or other substances on the surface of the wafer 7 without causing physical bombardment damage to the wafer circuitry.

[0026] The specific material and structural form of the grid 6 affect its function of "filtering ions and allowing free radicals to pass through". In one embodiment, the grid 6 is made of a conductive material (such as aluminum alloy, stainless steel, or a material with a conductive coating on its surface) and is grounded. When positively charged ions pass through the grid, they are neutralized by the grounded metal wall and thus eliminated, while electrically neutral free radicals can pass through smoothly.

[0027] In another embodiment, the grid 6 is made of an insulating material (such as quartz or ceramic). In this case, the filter pores on the grid 6 are designed with a preset aspect ratio (e.g., the ratio of pore depth to pore diameter is greater than a certain threshold). Ion quenching is achieved by utilizing multiple collisions and sidewall adsorption effects within the narrow channel, thereby achieving a filtration effect.

[0028] In a preferred embodiment, to balance ion filtration efficiency and free radical transport flux, the aperture ratio of the grid 6 is set between 30% and 60%. If the aperture ratio is too low, the concentration of free radicals reaching the wafer surface will be insufficient, reducing the process rate; if the aperture ratio is too high, it may lead to decreased mechanical strength or ion leakage. Simultaneously, the aspect ratio of the filter vias (i.e., the ratio of grid thickness to aperture) is set between 0.5:1 and 3:1. Preferably, the aspect ratio is greater than or equal to 1:1. By setting this aspect ratio, utilizing the multiple collisions of ions within the narrow channel and the sidewall adsorption effect, more than 90% of charged ions can be effectively filtered out, ensuring that the reactants reaching the wafer surface are mainly electrically neutral free radicals.

[0029] Specifically, the structural parameters of the grille 6 can be adjusted according to specific process requirements. The following are some typical example parameters: Example A (Focusing on High Transmission Rate): The grid 6 is made of aluminum alloy with a thickness of 3 mm to 5 mm. The diameter of the filter pores is 3 mm to 6 mm, and the aspect ratio is approximately 0.8:1 to 1:1. This example is suitable for roughing processes with low ion bombardment sensitivity but requiring a high ashing rate.

[0030] Example B (focusing on high ion filtration efficiency): The grid 6 is made of quartz or anodized aluminum with a thickness of 6 mm to 10 mm. The diameter of the filter vias is 2 mm to 4 mm, with an aspect ratio of approximately 1.5:1 to 3:1. With this high aspect ratio structure, charged ions in the plasma readily collide with and neutralize the via walls as they pass through. This example is particularly suitable for damage-free precision processes involving sensitive structures such as gate oxide layers.

[0031] In addition, the filter holes are arranged in a dense hexagonal honeycomb pattern on the surface of the grid 6 to maximize the porosity while ensuring mechanical strength.

[0032] In one implementation, such as Figure 1 As shown, the apparatus also includes an air intake unit (e.g., a spray head or air intake nozzle) located at the top of the media cylinder 4. The air intake unit passes through the cover plate or is directly integrated into the cover plate and is used to introduce process gas into the media cylinder 4. The process gas enters from the top, passes through the plasma excitation region, and then passes through the grid 6 to reach the process chamber 1 below.

[0033] like Figure 1 As shown, the plasma processing apparatus provided in this embodiment further includes an integrated gas path control device. To simplify equipment layout and achieve unified scheduling of process gases, the gas path control device is connected to the main exhaust pipe 3, the auxiliary exhaust pipe 8, and the intake pipe 5, respectively.

[0034] Despite in the appendix Figure 1 The gas path control device is shown as a single module, but those skilled in the art should understand that the gas path control device functionally integrates gas supply control and exhaust control functions, and its specific structure is as follows: 1. Gas Supply Function Module: The gas path control device internally includes a gas supply control unit (e.g., comprising a mass flow controller (MFC), pneumatic valves, etc.). One end of the gas supply control unit is connected to an external high-purity process gas source (not shown), and the other end is connected to the gas inlet pipe 5. During the process, the gas path control device is configured to regulate the flow rate of the process gas (such as etching gas or stripping gas) and deliver it to the reaction chamber via the gas inlet pipe 5 and the gas inlet unit at the top of the medium cylinder 4.

[0035] 2. Exhaust Function Module: The gas path control device also integrates a vacuum exhaust unit (e.g., including components such as a dry pump, turbomolecular pump, and throttle valve). Both the main exhaust pipe 3 and the auxiliary exhaust pipe 8 are connected to the intake port of this vacuum exhaust unit.

[0036] For the main exhaust pipe 3, the gas path control device controls the main control valve (second valve) installed on the main exhaust pipe 3 to pump gas from the process chamber 1 at a high flow rate to maintain the vacuum level required for plasma processing (e.g., 1 mTorr to 100 mTorr).

[0037] For the auxiliary adsorption system, the gas path control device controls the first valve set on the auxiliary exhaust pipe 8 to use the negative pressure provided by the vacuum exhaust unit to extract the gas from the back of the wafer 7 through the gas extraction channel 24 inside the tray 21.

[0038] This design, which integrates intake and exhaust control into the same physical unit (gas path control device), not only reduces the complexity of the piping at the bottom of the equipment, but also facilitates the unified management of the equipment's gas interlock safety mechanism, preventing the accidental introduction of toxic process gases when the vacuum system is not ready.

[0039] Furthermore, this disclosure provides two implementation schemes for the power source configuration of the auxiliary adsorption system and the main exhaust system: Option 1: The auxiliary adsorption system and the main exhaust system are connected to the same vacuum pump. In this configuration, the auxiliary exhaust pipe 8 merges into the rear end of the main exhaust pipe 3, or is connected to the pump inlet via a switching valve. This design reduces the equipment footprint and lowers hardware costs.

[0040] Option 2: Connect the auxiliary adsorption system to a separate vacuum pump. Since the pumping volume required for auxiliary adsorption is much smaller than the main process exhaust volume, and the start-up timing may need to be independently controlled, using a separate pump can avoid the main pump's strong suction causing instantaneous impact on the wafer, and can achieve more precise back negative pressure control.

[0041] The plasma processing apparatus also includes a radio frequency power supply electrically connected to the coil 9 via a matching network for providing radio frequency energy to the coil 9.

[0042] Figure 2 A side cross-sectional view of a tray 21 according to an embodiment of the present disclosure is shown. Figure 1 and Figure 2 As shown, in order to solve the wafer slippage problem, the bearing surface of the tray 21 (i.e. the upper surface in contact with the wafer 7) is provided with multiple adsorption holes 23.

[0043] The tray 21 includes a disc portion and a connecting rod portion 22 (such as...). Figure 1 (The columnar structure below the middle tray). The suction hole 23 communicates with the second air passage in the connecting rod portion 22 through the first air passage formed in the disc portion, together forming the suction channel 24. This suction channel 24 is connected to the external auxiliary exhaust pipe 8.

[0044] The auxiliary adsorption system may include an auxiliary exhaust pipe 8 extending from the connecting rod 22, and a first valve disposed on the pipe. The auxiliary exhaust pipe 8 may be connected to the same vacuum pump as the main exhaust pipe 3, or it may be connected to a separate vacuum pump.

[0045] In one embodiment, the material of tray 21 is selected according to the process temperature requirements. For high-temperature processes (such as above 400°C), tray 21 is preferably made of aluminum nitride (AlN) ceramic, taking advantage of its dual advantages of thermal conductivity and insulation; for conventional temperature processes, tray 21 can be made of aluminum alloy and subjected to surface anodizing treatment to improve corrosion resistance.

[0046] In one embodiment, a plurality of adsorption holes 23 are circular holes, arranged on the bearing surface to form concentric circles of at least one diameter. The diameter of the concentric circles is distributed according to the standard size of the workpiece (wafer 7) to be processed, including but not limited to 200mm (8 inches), 300mm (12 inches), or 450mm (18 inches). For example, an inner ring adsorption hole group and an outer ring adsorption hole group can be provided, wherein the distribution diameter of the inner ring adsorption hole group corresponds to the edge region of a 200mm wafer, and the distribution diameter of the outer ring adsorption hole group corresponds to the edge region of a 300mm wafer. This multi-region layout design allows the same tray 21 to be compatible with or specifically adapted to wafers of different sizes, ensuring that gas in the edge and center regions can be effectively extracted whether processing 8-inch or 12-inch wafers, preventing edge warping or slippage due to incomplete coverage.

[0047] In one embodiment, the multiple adsorption holes 23 can also be designed as strip-shaped openings (grooves), arranged in straight lines or arcs along the plane of the bearing surface. Multiple strip-shaped openings are arranged to form an adsorption port group surrounding the center of the tray. The length and radial position of the strip-shaped openings are also set based on common wafer sizes such as 200mm and 300mm. For example, the strip-shaped openings can extend radially, covering a range from a radius of 100mm (corresponding to an 8-inch edge) to a radius of 150mm (corresponding to a 12-inch edge). This design not only increases the adsorption area but also ensures that the suction channel is not completely blocked even when there is slight eccentricity in wafer placement, thereby maintaining a stable vacuum adsorption force.

[0048] In this embodiment, the diameter of the concentric circles or the distribution distance of the adsorption port group is determined according to the diameter of the workpiece to be processed (wafer 7) to ensure that the adsorption holes 23 are located within the area covered by the wafer 7 and to avoid air leakage.

[0049] This disclosure also provides a method for wafer processing using the above-described apparatus. The core of this method lies in resolving the slippage problem caused by the "air cushion" by controlling the specific operating timing of different pipelines using an air path control device. The method includes: Step S1: Transfer the wafer 7 and place it on the support surface of the tray 21. At this time, due to the fast falling speed and tight contact of the wafer, there is often residual process gas or transport gas between the wafer 7 and the tray 21, forming a micron-sized gas film (air cushion).

[0050] Step S2: Before the gas path control device opens the main control valve (second valve) on the main exhaust pipe 3, the first valve of the auxiliary adsorption system is opened first. At this time, using the negative pressure provided by the exhaust unit of the gas path control device, the residual gas between the wafer 7 and the tray 21 is directionally extracted through the suction channel 24 and the adsorption hole 23.

[0051] Step S2 can quickly eliminate the air cushion on the back of wafer 7, allowing wafer 7 to adhere tightly to the surface of tray 21 under negative pressure, significantly increasing the static friction between the two and achieving physical locking.

[0052] Step S3: Close the first valve of the auxiliary adsorption system (or, depending on process requirements, adjust the gas path control device to maintain a slight negative pressure on the back). At this point, wafer 7 has been stably adsorbed or attached to tray 21.

[0053] Step S4: Open the main control valve (second valve) on the main exhaust pipe 3. The gas path control device pumps a large flow of gas into the process chamber 1 through the main exhaust pipe 3 to quickly achieve the vacuum and pressure environment required by the process.

[0054] During this process, since the air cushion has been removed and the bonding has been achieved in step S2, even if the high-speed airflow generated by the main exhaust creates a lateral shear force on the wafer surface, the wafer 7 will not slide towards the exhaust port.

[0055] Step S5: The gas path control device activates its gas supply module, delivering a precise flow rate of process gas into the dielectric cylinder 4 via the inlet pipe 5 and the inlet unit. Simultaneously, radio frequency power is applied using coil 9 to excite the gas into plasma. After the generated plasma is filtered by grid 6 to remove ions, the remaining free radicals reach the surface of wafer 7 for chemical processing (such as etching or resist removal).

[0056] According to the solution of this disclosure embodiment, by adopting the control strategy of "extracting the back first and then the chamber", combined with the adsorption structure on the tray surface, the industry problem of wafer slippage during large volume and large pressure differential control is effectively solved, thereby improving the reliability of the equipment and the consistency of the process.

[0057] The plasma processing apparatus provided in this disclosure can be widely used in various dry processes in semiconductor manufacturing.

[0058] As a typical application scenario, this device can be configured as an inductively coupled plasma (ICP) etching apparatus. In this scenario, by introducing etching gas (such as a fluorine- or chlorine-containing gas) into the process chamber 1, high-density plasma is used to perform fine patterning etching of silicon oxide, polysilicon, or metal layers on the wafer surface. The anti-slip design of the aforementioned tray 21 is particularly critical in the high-flow step of the etching process, ensuring the alignment accuracy of pattern transfer.

[0059] As another preferred application scenario, given that this device is equipped with an ion-filtering grid 6, it is particularly suitable for dry ashing or descum removal equipment. In such processes, high-energy ions are filtered out by the grid 6, and only electrically neutral oxygen or hydrogen radicals react chemically with the photoresist on the wafer surface, thereby achieving flexible photoresist stripping. This process is typically accompanied by high process temperatures (e.g., above 250°C to 400°C) and large gas flow rates. In this disclosure, the adsorption function of the tray 21, combined with high-temperature resistant materials (such as aluminum nitride), effectively prevents wafer displacement under the impact of high-temperature gas flow, solving the common wafer slippage problem in the photoresist stripping process.

[0060] In addition, the device can also be used for surface treatment of wafers, such as surface activation or cleaning processes prior to thin film deposition.

[0061] Other components of the process chamber in the above embodiments can be constructed using various technical solutions known now and in the future to those skilled in the art, and will not be described in detail here.

[0062] In the description of this specification, it should be understood that the terms "center," "longitudinal," "transverse," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this disclosure.

[0063] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this disclosure, "multiple" means two or more, unless otherwise explicitly specified.

[0064] In this disclosure, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances.

[0065] In this disclosure, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0066] The foregoing disclosure provides many different implementations or examples for carrying out different structures of this disclosure. To simplify the disclosure, specific examples of components and arrangements have been described above. Of course, these are merely examples and are not intended to limit the scope of this disclosure. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various implementations and / or arrangements discussed.

[0067] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any person skilled in the art can easily conceive of various variations or substitutions within the technical scope disclosed in this disclosure, and these should all be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. A plasma processing apparatus, comprising: Process chamber (1), the process chamber (1) defines a reaction space for accommodating the workpiece to be processed; A medium cylinder (4) is connected to the top opening of the process chamber (1), and the medium cylinder (4) is in communication with the process chamber (1); A plasma generation unit is used to excite process gas in the medium cylinder (4) to generate plasma; The base assembly (2), disposed in the process chamber (1), includes a tray (21) and a connecting rod (22) supporting the tray (21), the tray (21) having a bearing surface for bearing the workpiece to be processed; The main exhaust system is connected to the process chamber (1) via the main exhaust pipe (3) and is used to regulate the pressure inside the process chamber (1); as well as An auxiliary adsorption system is used to discharge the gas between the workpiece to be treated and the bearing surface before the main exhaust system is activated; The bearing surface is provided with a plurality of adsorption holes (23), and the tray (21) and the connecting rod (22) are provided with an air extraction channel that connects the adsorption holes (23) and the auxiliary adsorption system. The auxiliary adsorption system includes an auxiliary exhaust pipe (8) connected to the air extraction channel and a first valve provided on the auxiliary exhaust pipe (8).

2. The plasma processing apparatus of claim 1, wherein, The arrangement of the plurality of adsorption pores on the bearing surface satisfies any of the following conditions: The plurality of adsorption pores are circular pores and are arranged in at least one concentric circle; The plurality of adsorption pores are strip-shaped grooves and are arranged radially or in a ring shape; The arrangement range of the adsorption holes is set based on the size of the workpiece to be processed.

3. The plasma processing apparatus according to claim 1, further comprising: The grid (6) is arranged laterally at the connection between the medium cylinder (4) and the process chamber (1) or inside the process chamber (1), located between the plasma generation area and the tray (21); The grid (6) is provided with a plurality of filter holes, which are configured to allow neutral free radicals in the plasma to pass through and block or reduce the passage of charged ions, so that the reactive substances reaching the surface of the workpiece to be treated are mainly free radicals.

4. The plasma processing apparatus according to claim 3, wherein, The grid (6) is made of a conductive material and grounded; or the grid (6) is made of an insulating material, and the filter holes have a preset aspect ratio to filter ions.

5. The plasma processing apparatus according to claim 1, wherein, The tray (21) is equipped with a heating unit, and the material of the tray (21) is selected from one of the following materials: Aluminum nitride ceramics are used to provide process temperatures above 400°C. Aluminum alloy with an anodized surface.

6. The plasma processing apparatus according to claim 1, wherein, The main exhaust system includes: The second valve is installed on the main exhaust pipe (3); The connection port between the main exhaust pipe (3) and the process chamber (1) is located on the side or below the tray (21) for lateral air extraction from the process chamber (1).

7. The plasma processing apparatus according to claim 1, wherein, The plasma generation unit includes: The radio frequency coil is wound around the outer wall of the dielectric cylinder (4); A radio frequency (RF) power supply, electrically connected to the RF coil, is used to couple RF energy to the process gas inside the dielectric cylinder.

8. The plasma processing apparatus according to claim 1, further comprising: An air intake unit is disposed at the top of the medium cylinder (4) for introducing process gas into the medium cylinder (4); A gas path control device is provided, wherein the main exhaust system, the auxiliary adsorption system, and the intake unit are all connected to the gas path control device; wherein the gas path control device is configured to supply gas to the intake unit and provide suction negative pressure for the main exhaust system and the auxiliary adsorption system.

9. A wafer processing method, comprising the following steps: S1: Place the wafer on the support surface of the tray of the plasma processing apparatus according to any one of claims 1 to 8; S2: Open the first valve to connect the adsorption hole on the tray with the negative pressure source. Use the negative pressure source to extract the residual gas between the wafer and the support surface through the adsorption hole to eliminate the air cushion effect and make the wafer adhere to the support surface. S3: Close the first valve; S4: Open the second valve of the main exhaust system, use the negative pressure source to evacuate and control the pressure of the process chamber (1), and carry out plasma treatment process.

10. The method according to claim 9, wherein, In S2, gas is extracted until a preset vacuum level is reached between the wafer and the bearing surface; In step S4, process gas is supplied to the dielectric cylinder through the air intake unit, and radio frequency power is applied to the plasma generation unit. The generated plasma reacts with the wafer after being filtered by a grid.

Images