Gas shower head, manufacturing method and plasma device including the gas shower head

Abstract

The present invention discloses a gas shower head, a manufacturing method and a plasma device including the gas shower head. The gas shower head includes a back plate and a gas distribution plate, the gas distribution plate includes a plurality of annular gas distribution areas with the circle center as the circle center; a plurality of gas through holes penetrating the gas inlet surface and the gas outlet surface are arranged on each annular gas distribution area, the gas through holes at least include a plurality of first gas through holes inclined at a certain angle along the radial direction, the gas through holes also include a plurality of second gas through holes, the second gas through holes are parallel to the central axis or have a different radial inclination direction from the first gas through holes; the gases flowing out of the first gas through holes and the second gas through holes in the same annular gas distribution area are away from each other.

Description

Technical Field

[0001] The invention relates to the field of semiconductor manufacturing, and in particular to a gas shower head for a plasma device, a manufacturing method thereof and a plasma device provided with the gas shower head. Background Art

[0002] A large amount of micro-processing is required during the production of semiconductor chips. Common plasma etching reactors can form various micron or even nano-sized through holes or grooves on the substrate, and then combine with other processes such as chemical vapor deposition to ultimately form various semiconductor chip products.

[0003] With the advancement of technology, the application and demand of ultra-deep aspect ratio etching are becoming more and more extensive. For example, in the field of memory, 3D NAND flash memory has become one of the main memory chip structures. The process of manufacturing 3D NAND chips includes first forming alternating silicon oxide and silicon nitride material layers, the number of layers can reach 64 layers or even hundreds of layers, and then plasma etching through all these material layers. Since the overall thickness of these material layers is very large, greater than 5um or even more than 8um, it belongs to ultra-deep aspect ratio etching.

[0004] When the number of etched silicon oxide and silicon nitride layers exceeds one hundred, it is difficult to ensure that the deep holes or grooves etched with current technology are vertical, and the sidewalls may tilt, and the tilt directions of different areas of the substrate are not exactly the same.

[0005] Therefore, in order to obtain vertically etched holes or grooves, researchers need to find out what causes the sidewall tilt and improve it. Summary of the invention

[0006] In view of the above problems in the background technology, the present invention proposes a gas shower head for a plasma device capable of improving uniformity.

[0007] A gas shower head for a plasma device, the gas shower head comprising a gas distribution plate having an inlet surface and an outlet surface, the gas distribution plate being a disc-shaped structure having a center, comprising a central axis passing through the center and perpendicular to the gas distribution plate, the gas distribution plate comprising a plurality of annular gas distribution areas having the center as the center;

[0008] A plurality of gas through holes penetrating the gas inlet surface and the gas outlet surface are arranged on each annular gas distribution area, wherein the gas through holes at least include a plurality of first gas through holes inclined at a certain angle in the radial direction, and the gas through holes further include a plurality of second gas through holes, wherein the second gas through holes are parallel to the central axis or have a different radial inclination direction from the first gas through holes;

[0009] The gases flowing out of the first gas through hole and the gases flowing out of the second gas through hole in the same annular gas distribution area are away from each other.

[0010] Optionally, the gas outlet directions of the plurality of first gas through holes are inclined toward a direction close to the central axis, and the gas outlet directions of the plurality of second gas through holes are inclined toward a direction away from the central axis or are parallel to the central axis.

[0011] Optionally, the gas outlet directions of the plurality of first gas through holes are inclined away from the central axis, and the gas outlet directions of the plurality of second gas through holes are inclined toward the central axis or are parallel to the central axis.

[0012] Optionally, the first gas through hole and the second gas through hole in the same annular gas distribution area have a first radial distance difference from the opening center of the gas inlet surface to the central axis, and the first gas through hole and the second gas through hole in the same gas distribution area have a second radial distance difference from the opening center of the gas outlet surface to the central axis, and the second radial distance difference is greater than the first radial distance difference.

[0013] Optionally, in the same gas distribution area, the distances from the opening centers of the first gas through holes and the second gas through holes on the gas inlet surface to the central axis are equal, and the first gas through holes and the second gas through holes are alternately arranged.

[0014] Optionally, in the same gas distribution area, the distances from the opening centers of the first gas holes and the second gas holes on the gas inlet surface to the central axis are equal, a number of adjacent first gas holes form a first gas unit, a number of adjacent second gas holes form a second gas unit, and the first gas units and the second gas units are alternately arranged.

[0015] Optionally, the gas outlet directions of the multiple first gas holes are inclined toward the direction close to the central axis, and the gas outlet directions of the multiple second gas holes are inclined toward the direction away from the central axis. A plurality of third gas holes are also arranged on the gas distribution plate, and the third gas holes are parallel to the central axis. The first gas holes, the second gas holes and the third gas holes are arranged alternately at intervals.

[0016] Optionally, in the same gas distribution area, there is a radial distance difference greater than 0 between the opening centers of the first gas through hole and the second gas through hole on the gas inlet surface and the central axis.

[0017] Optionally, in the same gas distribution area, the radial distance from the opening center of the first gas through hole on the air inlet surface to the central axis is smaller than the radial distance from the opening center of the second gas through hole on the air inlet surface to the central axis, and the opening centers of the first gas through hole and the second gas through hole on the air inlet surface are located in the same radial direction.

[0018] Optionally, in the same gas distribution area, the radial distance from the opening center of the first gas through hole on the air inlet surface to the central axis is smaller than the radial distance from the opening center of the second gas through hole on the air inlet surface to the central axis, and the opening centers of the first gas through hole and the second gas through hole on the air inlet surface are respectively located in different radial directions.

[0019] Optionally, the first inclination angle and the second inclination angle are greater than or equal to 0° and less than 30°.

[0020] Optionally, an angle between the first gas through hole and the second gas through hole is greater than or equal to 5°.

[0021] Optionally, an annular isolation zone is arranged between two adjacent annular gas distribution zones, and the annular gas distribution zones and the annular isolation zones are alternately distributed in radial direction.

[0022] Optionally, the radial width of the annular isolation zone is greater than the radial width of the gas distribution zone.

[0023] Optionally, the gas shower head further includes a back plate, the back plate is opposite to the gas inlet surface of the gas distribution plate, and a plurality of heat conduction layers are arranged between the back plate and the gas distribution plate.

[0024] Optionally, the heat conduction layer is arranged on the upper surface of the annular isolation area.

[0025] Optionally, at least a portion of the openings of the first gas through holes or the second gas through holes on the gas outlet surface are located within the orthographic projection area of ​​the heat conduction layer on the gas outlet surface of the gas distribution plate.

[0026] Optionally, the air inlet surface includes a plurality of grooves, each of the grooves has an inclined bottom surface, and the first gas through hole is arranged on the inclined bottom surface of the groove.

[0027] Optionally, the groove includes a side wall that is recessed along the air inlet surface toward the air outlet surface and an inclined bottom surface that forms a certain angle with the side wall.

[0028] Optionally, the groove includes two inclined bottom surfaces inclined in different directions, and the two inclined bottom surfaces form a "V"-shaped groove.

[0029] Optionally, the first gas through hole and the second gas through hole extend perpendicularly to the inclined bottom surface of the groove toward the gas outlet surface.

[0030] Optionally, a plurality of countersunk holes are arranged in the groove, the countersunk holes are arranged on the inclined bottom surface of the groove, and the openings of the gas through holes are arranged on the inclined bottom surface of the countersunk holes.

[0031] Optionally, a plurality of countersunk holes are arranged on the air inlet surface, each of the countersunk holes has an inclined bottom surface, and the opening of the gas through hole is arranged on the inclined bottom surface of the countersunk hole.

[0032] Furthermore, the present invention also discloses a plasma device, comprising a vacuum reaction chamber, wherein the vacuum reaction chamber is provided with:

[0033] A base, used to support the substrate to be processed;

[0034] A gas shower head, arranged opposite to the base, and used for providing reaction gas into the vacuum reaction chamber;

[0035] A radio frequency source power source, used to dissociate the reaction gas to generate plasma;

[0036] a radio frequency bias power source, applied to the base, for driving charged particles in the plasma to process the substrate;

[0037] The gas shower head has the features as claimed in claim 1.

[0038] Optionally, the output frequency of the RF bias power source is greater than or equal to 10,000 watts.

[0039] Optionally, the depth-to-width ratio of the substrate etching is greater than or equal to 40:1.

[0040] Optionally, the etching target layer of the substrate is greater than or equal to 100 layers.

[0041] Optionally, the output frequency of the RF bias power source is greater than or equal to 100Khz and less than or equal to 2Mhz.

[0042] Optionally, the RF bias power source outputs a pulsed RF bias signal.

[0043] Optionally, the gas pressure in the reaction chamber is less than or equal to 100 mTorr.

[0044] Furthermore, the present invention also discloses a method for manufacturing the gas shower head mentioned above, comprising the following steps:

[0045] A disc-shaped gas distribution plate is provided, wherein the gas distribution plate comprises a gas inlet surface, a gas outlet surface and a central axis perpendicular to the gas distribution plate.

[0046] A plurality of annular gas distribution areas are arranged on the gas distribution plate, and a plurality of first gas through holes with a first inclination angle and a plurality of second gas through holes with a second inclination angle are arranged in each of the gas distribution areas, wherein the gas outlet direction of the plurality of first gas through holes is inclined toward the direction close to the central axis, and the gas outlet direction of the plurality of second gas through holes is inclined toward the direction away from the central axis.

[0047] Optionally, a plurality of annular grooves are formed on the gas inlet surface of the gas distribution plate, and the annular grooves have at least one inclined bottom surface;

[0048] The angle between the inclined bottom surface and the air inlet surface is 0°-30°, and the first gas through hole and the second gas through hole are arranged perpendicular to the inclined bottom surface.

[0049] Optionally, when making the groove, a recessed portion with a certain depth is first made perpendicular to the air inlet surface and toward the air outlet surface, and then an inclined bottom surface is made on the bottom surface of the recessed portion.

[0050] Optionally, a plurality of countersunk holes are arranged on the inclined bottom surface, and the air inlet of the gas through hole is arranged at the bottom of the countersunk hole.

[0051] Optionally, the diameter of the countersunk hole is larger than the diameter of the gas through hole. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 It is a schematic structural diagram of the plasma device of the present invention;

[0053] Figure 2 It is a schematic diagram of the morphology of the etching result obtained by etching a substrate in the prior art;

[0054] Figure 3 It is a schematic diagram of the effect of the gas showerhead hole spacing on the substrate surface;

[0055] Figure 4 It is a partial structural schematic diagram of the gas shower head shown in the present invention;

[0056] Figure 5A-5D A schematic diagram showing the structure of a gas distribution plate according to an embodiment of the present invention;

[0057] Figure 5E A schematic diagram showing the structure of a gas distribution plate according to an embodiment of the present invention

[0058] Figure 6A-6C A schematic diagram showing the structure of a gas distribution plate according to an embodiment of the present invention;

[0059] Figure 7A-7B A schematic diagram showing the structure of a gas distribution plate according to an embodiment of the present invention;

[0060] Figure 8A-8C A schematic diagram showing the structure of a gas distribution plate according to an embodiment of the present invention;

[0061] Fig. 9 A schematic diagram showing the structure of a gas distribution plate according to an embodiment of the present invention;

[0062] Fig.10 A schematic diagram showing the structure of a gas distribution plate according to an embodiment of the present invention;

[0063] Fig.11 A schematic diagram showing the structure of a gas distribution plate according to an embodiment of the present invention;

[0064] Fig.12 The figure is a schematic diagram of the morphology of etching results obtained by etching a substrate using the device of the present invention. DETAILED DESCRIPTION

[0065] The specific implementation of the present invention is described below in conjunction with the accompanying drawings.

[0066] The present invention provides a plasma device for ultra-deep aspect ratio etching, such as Figure 1 As shown, it includes a vacuum reaction chamber 50 surrounded by the outer wall 30 of the reaction chamber, and a reaction space is formed inside the vacuum reaction chamber for plasma etching process treatment; a base 40 is arranged in the vacuum reaction chamber for fixing the substrate W to be processed, and the base 40 also serves as the lower electrode of the vacuum reaction chamber. A flat gas shower head 10 is arranged on the top of the reaction chamber, and the gas shower head 10 is connected to the external gas source 20 through a pipeline. The gas shower head corresponds to the position of the base and also serves as the upper electrode of the vacuum reaction chamber. A radio frequency source power source 72 can be selectively applied to one of the upper electrode or the lower electrode to generate a high-frequency electric field between the upper electrode and the lower electrode, so that the reaction gas introduced into the reaction chamber is ionized to generate plasma. A radio frequency bias power source 74 is applied to the lower electrode, so that sufficient DC bias voltage is generated in the sheath layer on the upper surface of the substrate, accelerating the charged ions in the plasma to quickly bombard the substrate for etching. A plasma confinement device 60 is disposed around the susceptor 40 to confine the plasma in the plasma zone, and a vacuum pumping device 80 is used to exhaust the unreacted gas and reaction byproduct gas in the reaction chamber to maintain the vacuum state of the reaction chamber 50 .

[0067] As a processing purpose, the substrate W processed in the vacuum reaction chamber of the present invention includes several insulating material layers. A typical application is a 3D NAND substrate, including a first insulating material layer 1 and a second insulating material layer 2 alternately stacked, such as Figure 2The first insulating material layer 1 is made of silicon oxide, and the second insulating material layer 2 is made of silicon nitride. The cumulative number of silicon oxide layers and silicon nitride layers is greater than or equal to 100. The aspect ratio of the through hole formed by etching on the insulating material layer is greater than or equal to 40.

[0068] During the etching process, it was found that as the etching depth continued to increase, it was difficult to ensure that the side walls of the etched deep holes were vertical. Test results showed that the deep holes or grooves obtained by etching often tilted and twisted, and the tilt directions and tilt angles in different areas were not exactly the same. Figure 2 A schematic diagram showing the etching results obtained so far is shown. Figure 2 It was found that some of the holes or grooves on the etched substrate were distorted, while the etching morphology of the other holes or grooves was good and met the process requirements, and the inclination angles and distortion directions of the unqualified holes or grooves on both sides of the etched holes or grooves with good morphology sometimes had a mirror image phenomenon. At the same time, the inventor found that the spacing L1 between adjacent etched holes or grooves that met the requirements was consistent with the spacing L1 between two adjacent gas outlets in the gas shower head. Therefore, the inventor speculated that the distribution of gas through holes on the gas shower head in the reaction chamber has an important influence on the uniformity of substrate etching.

[0069] In order to verify the above speculation, the inventors conducted Figure 3 In the test shown, a test substrate W is placed in a plasma reaction chamber, and a certain amount of deposition gas is introduced into the gas shower head. After a period of time, it is found that the thickness of the film deposited in the area W1 corresponding to the gas through holes under the gas shower head is smaller than that in the area W2 corresponding to the area between adjacent gas through holes. This confirms that the distribution of gas through holes on the gas shower head has an important influence on the uniformity of substrate etching.

[0070] Since one purpose of the plasma reactor designed by the present invention is to etch holes or grooves with ultra-high aspect ratios, in order to obtain etching results with better morphology, the reaction gas includes both etching gas and deposition gas. Especially in the process of etching high aspect ratios, the etching of holes or grooves is a process in which the etching process and the deposition process are carried out simultaneously. The inventors have found that no matter in the etching process or the deposition process, the undissociated gas in the reaction gas basically does not participate in the reaction, and only the neutral free radicals or charged particles in the plasma will carry out etching or deposition reactions. Therefore, after the reaction gas flows out of the gas shower head 10 at a certain speed, a part of the gas is vertically sprayed to the substrate surface to form a molecular flow, and the other part of the gas diffuses to the surroundings and flows to the substrate surface at a lower speed to form a transition molecular flow. Since the diffusion path of the transition molecular flow gas is longer and the time spent in the plasma dissociation area is longer, the dissociation produces more free radicals and charged particles that can participate in the etching reaction and the deposition reaction, while the molecular flow gas is vertically sprayed to the substrate surface, and the dissociation produces fewer free radicals and charged particles. Therefore, the substrate surface area W1 to which the molecular flow is sprayed has fewer components participating in the etching reaction or the deposition reaction than other areas W2. Therefore, uneven processing will occur on the substrate surface. When the mask layer on the substrate surface is unevenly processed, the etched deep holes or grooves will be distorted and tilted when the etching pattern is transferred downward.

[0071] In order to solve the above technical problems, the present invention provides a gas shower head, such as Figure 4As shown, the gas shower head includes a back plate 15 and a gas distribution plate 100. A plurality of gas through holes are provided on the gas distribution plate to transport the reaction gas between the upper and lower electrodes. Since the gas distribution plate of the gas shower head contacts the plasma during the etching process, in order to ensure the uniform treatment of the substrate by the plasma, it is necessary to maintain the temperature uniformity of different areas of the gas distribution plate. In the present invention, the material of the back plate is usually aluminum, and the material of the gas distribution plate is usually a ceramic material resistant to plasma corrosion. In some processes, the temperature of the gas distribution plate is too high and the temperature is uneven due to the bombardment of the gas distribution plate by the plasma, which may cause the cracking of the gas distribution plate. As the reaction process continues, the gradually heated gas distribution plate will cause different batches of substrates to have different processing degrees, reducing the repeatability of the equipment, so it is necessary to cool the gas distribution plate. In other processes, sometimes it is necessary to uniformly heat the gas distribution plate. Since the gas distribution plate is full of gas through holes, there is not enough space to set the temperature regulating device. Therefore, the present invention sets the temperature regulating device inside the back plate 15. The temperature regulating device includes a heating device and a cooling device, which will not be repeated here. In order to achieve temperature control of the gas distribution plate and to avoid poor contact caused by different thermal expansion coefficients of substrates of different materials and the gas distribution plate, the present invention sets a heat conduction layer 104 between the back plate 15 and the gas distribution plate 100. The heat conduction layer 104 can ensure good thermal contact between the gas distribution plate and the back plate. The temperature of the gas distribution plate is controlled by controlling the temperature control device in the back plate to improve the temperature uniformity of the entire gas distribution plate. When processing different areas of the same substrate and different batches of substrates, the gas distribution plate can have good uniformity and repeatability.

[0072] In the case of a limited number of gas through holes, in order to ensure the etching rate of the substrate, it is necessary to provide sufficient reaction gas to the vacuum reaction chamber, therefore, the reaction gas in each gas through hole needs to have a certain flow rate. In order to avoid uneven processing on the substrate surface, after eliminating the influence of the electric field distribution in the reaction chamber, the inventors found that the size of the gas flow out of the gas distribution plate and the degree of gas diffusion are the main reasons for the inclination of the etched deep holes. If the reaction gas rate flowing out of the gas through hole is reduced, it will help solve the problem of distortion and inclination of the etched deep holes. However, reducing the gas flow rate in the gas through hole will cause the total amount of reaction gas supplied to the vacuum reaction chamber to decrease, which will then cause the etching rate of the substrate to decrease, and it is impossible to meet production needs. If the number of gas through holes is increased, since the gas through holes are distributed in an annular shape on the gas distribution plate, and a larger heat conduction layer is set between adjacent annular gas through holes, and the distance between the two heat conduction layers is small, it can only be achieved by increasing the number of gas through holes between two adjacent gas through holes. However, when the number of gas through holes is increased, the gas outlets on the gas outlet surface of the gas distribution plate will become more dense. When the reaction gas flows downward to the substrate surface, the distance between the outlets of two adjacent gas through holes is small, and the gas at the outlets will be connected into one piece, resulting in a gas curtain phenomenon. The annular gas curtain will have a worse effect on the processing uniformity of the substrate, so the present invention needs to provide a gas shower head that can uniformly process the substrate.

[0073] like Figure 4 As shown, a plurality of gas channels are arranged on the back plate 15. The reaction gas enters the back plate from the external gas source 20 through the gas delivery pipeline, is mixed or evenly distributed in the back plate, and then enters the plasma dissociation area between the upper electrode and the lower electrode through the gas through holes on the gas distribution plate. It is used to distribute the reaction gas and transport it to the inside of the gas distribution plate 100. A plurality of gas through holes are arranged on the gas distribution plate 100 to evenly distribute the reaction gas transported from the back plate. Since the gas shower head is usually disc-shaped, the gas through holes and the heat conduction layer are usually arranged in a circular ring shape. In order to ensure good thermal contact between the back plate and the gas distribution plate, the area of ​​the heat conduction layer should be as large as possible. Since the gas inlet of the gas through hole can only be arranged on the side of the heat conduction layer, and in order to ensure the uniform distribution of the gas through holes on the gas distribution plate, annular gas through holes and annular heat conduction layers are usually arranged alternately.

[0074] exist Figure 4In the gas shower head shown, one side of the gas distribution plate 100 adjacent to the back plate 15 is the gas inlet surface 101, and the other side is the gas outlet surface 102, and the gas through holes 110 are obliquely arranged inside the gas distribution plate. Considering that the current substrates are all circular, in order to uniformly process the substrates, the present invention designs the gas distribution plate to be a disc-shaped structure with a center, and assumes that there is a central axis passing through the center and perpendicular to the gas distribution plate, the gas distribution plate includes a plurality of annular gas distribution areas with the center as the center, each annular gas distribution area is provided with a plurality of gas through holes passing through the gas inlet surface and the gas outlet surface, the gas through holes at least include a plurality of first gas through holes inclined at a certain angle along the radial direction, the gas through holes also include a plurality of second gas through holes, the second gas through holes are parallel to the central axis or have a different radial inclination direction from the first gas through holes; Figure 4 In the embodiment shown, the gas outlet directions of the plurality of first gas through holes are inclined toward the direction close to the central axis, and the gas outlet directions of the plurality of second gas through holes are inclined toward the direction away from the central axis, thereby ensuring that the gases flowing out of the plurality of first gas through holes and the second gas through holes in the same annular gas distribution area are away from each other and do not converge. The structural design of the present invention will be described in detail below.

[0075] Figures 5A-5D A schematic diagram of an exemplary gas distribution plate structure of the present invention is shown, wherein Figure 5A This is the gas inlet surface view of the gas distribution plate. Figure 5B This is the gas outlet surface view of the gas distribution plate. Figure 5C It is a cross-sectional view of the gas distribution plate along RR. Figure 5D Schematic diagram of the inclination angles of the first gas through hole and the second gas through hole in the same gas distribution area. Figures 5A-5D In the illustrated embodiment, a plurality of annular gas distribution areas 106 are provided on the gas distribution plate 100, and a plurality of gas through holes 110 penetrating the gas inlet surface 101 and the gas outlet surface 102 are provided in each annular gas distribution area. For the convenience of processing and manufacturing, the gas through holes are arranged on the gas distribution plate in circles according to different diameters with the center of the gas distribution plate as the center. In the present embodiment, a circle of gas through holes is provided in each annular gas distribution area. An annular isolation area 105 is provided between two adjacent annular gas distribution areas, and no gas through holes are provided on the annular isolation area. In the present embodiment, the annular gas distribution areas 106 and the annular isolation areas 105 are radially alternately distributed.

[0076] In order to match the design of the gas through holes and to ensure the heat transfer effect, a heat conduction layer 104 is provided on the upper surface of the annular isolation area 105. The heat conduction layer 104 is also distributed between two adjacent circles of gas through holes in an annular structure.

[0077] Depend on Figure 5CIt can be seen that the gas through holes are arranged obliquely inside the gas distribution plate. In the same annular gas distribution area, the gas through holes include a plurality of first gas through holes 110a having a first inclination angle and a plurality of second gas through holes 110b having a second inclination angle. Figure 5A As shown, the radial width of the annular isolation area 105 is greater than the radial width of the annular gas distribution area 106. In this embodiment, only one circle of gas through holes is provided on each annular gas distribution area 106, that is, the distances from the opening centers of the first gas through hole 110a and the second gas through hole 110b on the gas inlet surface 101 to the central axis are equal in the same gas distribution area, and the first gas through hole 110a and the second gas through hole 110b are alternately arranged. The two groups of gas through holes have different radial inclination directions. Specifically, the gas through hole 110a is inclined at a certain angle toward the central axis, and the gas outlet direction of the gas through the gas through hole 110a is close to the central axis, and the gas through hole 110b is inclined at a certain angle toward the direction away from the central axis, and the gas outlet direction of the gas through the gas through hole 110b extends toward the direction away from the central axis. The gases of the first gas through hole and the second gas through hole in the same annular gas distribution area are far away from each other and do not converge. In other embodiments, the first gas through hole and the second gas through hole do not strictly follow the rule of alternating with each other. For example, a plurality of adjacent first gas through holes form a first gas unit, and a plurality of adjacent second gas through holes form a second gas unit, and the first gas unit and the second gas unit are arranged alternately. The inclination angles of the gas through hole 110a and the gas through hole 110b may be the same or different, wherein the first inclination angle α of the first gas through hole is the angle between the gas through hole 110a and the air inlet surface 101, and the angle range is 60° to 90 degrees. Similarly, the second inclination angle β of the second gas through hole is the angle between the gas through hole 110b and the air inlet surface 101, and the angle range is 60° to 90 degrees. Figure 5D For the convenience of description, in this embodiment, the gas through hole 110a and the gas through hole b have the same inclination angle but different inclination directions.

[0078] according to Figure 5B As shown, in this embodiment, since the first gas through holes 110a are inclined at the same angle toward the central axis, these gas outlets also have the same radial distance on the gas outlet surface. Similarly, the second gas through holes 110b are inclined at the same angle away from the central axis, and the second gas through holes 110b also have the same radial distance on the gas outlet surface. Figure 5A and Figure 5BIt can be seen that a circle of gas through holes at the same radial distance on the air inlet surface 101 is changed into two circles of gas through holes on the air outlet surface 102. Compared with the distance between two adjacent air inlets on the gas through hole circle at the same radial distance on the air inlet surface, the distance between two adjacent air outlets on the same gas through hole circle on the air outlet surface increases. At the same time, compared with the radial difference between two circles of gas through holes in two adjacent annular gas distribution areas on the air inlet surface, the radial difference between two adjacent circles of gas through holes on the air outlet surface decreases, so the opening distribution of the gas through holes on the air outlet surface is more uniform. Compared with the prior art, although the number of openings of the gas through holes on the air inlet surface has doubled, the present invention cleverly designs the gas through holes to be inclined at a certain angle, so that the distance between two adjacent gas through holes in the same annular gas distribution area on the air outlet surface is not reduced, so the problem of the air curtain forming at the outlet of the same circle of gas through holes due to the too small distance between adjacent gas through holes will not occur.

[0079] In other embodiments, the inclination angles of the gas through holes can be set to different levels, as long as the gas outlets can be evenly distributed on the gas outlet surface and the gas inlet on the gas inlet surface does not affect the setting of the heat conduction layer, it complies with the inventive concept of the present invention.

[0080] In the embodiment of the present invention, the first gas through hole and the second gas through hole located in the same annular gas distribution area can be simultaneously set to have an angle of 60°-90° with the air inlet surface, or one group of gas through holes can be set to have a certain inclination angle, and the other group of gas through holes can be parallel to the central axis along the vertical direction. Figure 5E In the embodiment shown, a third group of gas through holes 110c is provided, and a third inclination angle is provided between the third group of gas through holes and the air inlet surface. Preferably, the third inclination angle is smaller than the first inclination angle and the second inclination angle. In this embodiment, the third inclination angle is set to 90°, parallel to the central axis in the vertical direction. In this embodiment, the first gas through hole, the second gas through hole and the third gas through hole are alternately provided, so that the gas through holes in the same annular gas distribution area form three circles of gas outlets on the air outlet surface, thereby improving the uniform distribution of the gas through holes on the air outlet surface. Since the distance between the gas outlets in two adjacent annular gas distribution areas on the air outlet surface is related to the angle between the two adjacent gas through holes and the thickness of the gas distribution plate, when one of the two adjacent gas through holes in the same annular gas distribution area is provided with a larger inclination angle and the other is provided perpendicular to the air outlet surface, the distance between the two adjacent circles of gas outlets on the air outlet surface can also be increased, thereby avoiding the generation of a gas curtain.

[0081] according to Figure 5CAs shown, the openings arranged on the air inlet surface of the gas distribution plate can only be located on both sides of the heat conduction layer, and the heat conduction layer 104 has a positive projection area 104a on the air outlet surface 102. According to the embodiment shown above, since the gas through holes of the present invention have a certain inclination angle, the gas outlet of the gas through hole 110 on the air outlet surface 102 is at least partially located within the projection area 104a. The design of the present invention allows the gas outlet to bypass the limitation of the heat conduction layer, fully utilizes the space of the air outlet surface, reduces the distance between the outlets of two adjacent circles of gas through holes, and makes the air outlets of the gas through holes more evenly distributed on the air outlet surface.

[0082] In this embodiment, by setting the gas through holes to have a certain inclination angle or two or more groups of gas through holes in the same gas distribution area to have an angle greater than 5°, the gas outlet distribution on the lower surface of the gas distribution plate can be made more uniform while ensuring that the area of ​​the heat conduction layer is not reduced, and the gas curtain phenomenon that may be caused by the close distance between two adjacent gas outlets can be avoided. In this embodiment, the number of gas through holes is greatly increased, so the gas flow rate in each gas through hole can be effectively reduced without reducing the total amount of gas supplied to the vacuum reaction chamber, avoiding the reaction gas from being sprayed onto the substrate surface without dissociation, and improving the uniformity of the substrate surface and other areas under the gas through holes.

[0083] In this embodiment, in order to ensure the heat conduction effect between the gas distribution plate and the back plate, the area of ​​the heat conduction layer should be set as large as possible. Therefore, the heat conduction layer is set between two adjacent circles of gas through holes as much as possible. However, in other embodiments, two circles of gas through holes can also be set between two adjacent circles of heat conduction layers. Figures 6A-6C An embodiment of a gas distribution plate 200 is shown.

[0084] exist Fig. 6A In the schematic diagram of the gas distribution plate air intake surface structure shown in the figure, there is a radial distance difference greater than 0 between the first gas through hole and the second gas through hole on the air intake surface of the same annular gas distribution area and the central axis, that is, two circles of gas through holes 210 are set on the air intake surface of the same annular gas distribution area. The distance between the air intake ports of the two circles of gas through holes on the air intake surface 201 is small to adapt to the small distance between the two adjacent circles of heat conduction layers. Fig. 6A In the embodiment shown, the first gas through holes and the second gas through holes in the same annular gas distribution area are located in the same radial direction and are evenly arranged in their respective annular gas distribution areas. Figure 6CIn the cross-sectional view shown, the first gas through hole 210a is inclined toward the central axis, so that there is a first inclination angle α between the first gas through hole and the air inlet surface, and the second gas through hole 210b is inclined away from the central axis, so that there is a second inclination angle β between the second gas through hole and the air inlet surface. The first inclination angle α and the second inclination angle β may be the same or different, and the first inclination angle α and the second inclination angle β are in the range of 60°-90°.

[0085] Depend on Figure 6B It can be seen from the schematic diagram of the gas outlet surface 202 of the gas distribution plate shown that the distance between the gas outlets of two closely adjacent circles of gas inlets on the gas inlet surface becomes larger. Assuming that the opening centers of the first gas through hole and the second gas through hole on the gas inlet surface have a first radial distance difference from the central axis, and the opening centers of the first gas through hole and the second gas through hole on the gas outlet surface in the same gas distribution area have a second radial distance difference from the central axis, it can be seen from the embodiment of the present invention that the second radial distance difference is greater than the first radial distance difference. Therefore, the opening distribution of the gas through holes on the gas outlet surface is more uniform than the opening distribution on the gas inlet surface. When the number of gas through holes is increased, the distance between the openings of two adjacent gas through holes with the same radial distance on the gas outlet surface does not decrease. Therefore, it is avoided that the gas outlets in the same annular gas distribution area are too dense to form a gas curtain, which affects the uniformity of substrate processing.

[0086] Fig. 7A and Figure 7B Another embodiment is shown. In this embodiment, two circles of gas through holes are also set in the same annular gas distribution area. Unlike the above embodiment in which the first gas through hole and the second gas through hole are distributed in the same radial direction, the first gas through hole and the second gas through hole in this embodiment are staggered and located in different radial directions. The gas through hole close to the inner circle is inclined at an angle toward the central axis, and the second gas through hole close to the outer circle is inclined at another angle away from the central axis. These two angles can be the same or different. The gas through holes on both sides of the annular heat conduction layer are reasonably arranged to ensure that the gas outlets are evenly distributed on the gas outlet surface.

[0087] In both of the above-mentioned two embodiments, two circles of gas through holes are arranged in the same annular gas distribution area. In other embodiments, more than two circles of gas through holes may be arranged in the same annular gas distribution area. Due to the limitation that gas through holes cannot be arranged on the annular isolation area between two adjacent annular gas distribution areas, and the radial dimension of the annular isolation area is larger than the radial dimension of the gas through holes, the gas through holes in the same annular gas distribution area are arranged relatively densely on the air inlet surface. The present invention increases the distance between the air outlets of several circles of gas through holes in the same annular gas distribution area on the air outlet surface by arranging the gas through holes with a certain inclination angle. On the premise of increasing the number of gas through holes, a gas curtain will not be formed, thereby ensuring that the reaction gas is evenly supplied to the reaction chamber.

[0088] same Figure 5C The embodiment shown, Figures 6A-6C and Figure 7A-7B In the embodiment shown, at least part of the gas outlets are located in the projection area of ​​the heat conduction layer on the gas outlet surface, so that the space on the gas outlet surface can be fully utilized and the gas outlets can be evenly arranged.

[0089] In order to meet the needs of etching equipment with high aspect ratios, the present invention increases the number of gas holes on the original gas distribution plate technology. By setting the gas holes to have a certain inclination with the vertical direction, it is ensured that while the number of gas holes is increased, there will be no problems such as gas curtains that affect the uniform processing of the substrate. As the number of gas holes on the gas distribution plate increases, in order to match the gas holes on the gas distribution plate, the back plate above it must also be improved. One way is to simultaneously increase the number of gas holes on the gas distribution plate, but this will increase costs. At the same time, designing a new back plate will also extend the design cycle and increase component management costs.

[0090] In order to solve the above problems, the present invention is further improved on the basis of the embodiments described above, and the designed gas distribution plate can be applied to the existing backplane and has better gas uniformity.

[0091] Figures 8A-8C A gas distribution plate 400 with grooves arranged on the gas inlet surface is shown schematically, wherein: Fig. 8A 401 is a schematic diagram of the structure of the gas inlet surface of the gas distribution plate. Figure 8B 402 is a schematic diagram of the structure of the gas outlet surface of the gas distribution plate. Figure 8C Figure 1 is a schematic diagram of the cross-sectional structure of the gas distribution plate. Fig. 8A In the embodiment, a groove 420 with a certain inclination angle is provided in the annular gas distribution area. In order to make full use of the space between the heat conducting layers, the groove 420 may have one inclined bottom surface or may include two inclined bottom surfaces 420a and 420b. The two inclined bottom surfaces make the groove 420 V-shaped. The inclination angles of the two inclined bottom surfaces may be the same or different. Figure 8CAs can be seen from the cross-sectional schematic diagram, a circle of first gas through holes 410a and second gas through holes 410b with a certain inclination angle are respectively arranged on the two inclined surfaces of the groove 420. Figure 8C In the embodiment shown, the first gas through hole 410a and the second gas through hole 410b located in the same annular gas distribution area are staggered and spaced apart, located in different radial directions, and have a certain distance between each other. In another embodiment, the first gas through hole 410a and the second gas through hole 410b can be arranged in pairs on the gas inlet surface, and are located in pairs on the same radial direction, such as Fig. 6A Embodiment described.

[0092] exist Figures 8A-8C In the described embodiment, the groove 420 is provided to greatly reduce the difficulty of making the inclined hole. Since the diameter of the gas through hole on the gas distribution plate is relatively small, usually about 1 mm, when a drill with a smaller diameter processes the inclined hole on a plane, the drill is very likely to break. However, the present invention provides two inclined surfaces 420a and 420b according to the angle and direction of the gas through hole to be inclined, which can ensure that the drill is still perpendicular to the processing surface (i.e., the inclined surfaces 420a and 420b) when processing the inclined hole, avoiding damage to the drill and reducing the difficulty of making the inclined gas through hole.

[0093] In addition, the groove 420 formed by the inclined surfaces 420a and 420b also forms a guide groove for uniform gas distribution. According to the above, under the premise of not changing the existing back plate design as much as possible, the original gas channel of the back plate transports the reaction gas into the groove 420, and evenly diffuses in the groove 420 to form a gas isobaric zone. After the uniform diffusion of the groove 420, the reaction gas entering the reaction chamber from the first gas through hole 410a and the second gas through hole 410b can be guaranteed to be as uniform as possible. The present invention increases the number of gas through holes on the gas distribution plate without changing the existing back plate. By setting the groove 420 on the air inlet surface, the uniform distribution of the gas is ensured, and at the same time, Figure 8B It can be seen from the schematic diagram of the outlet surface structure that the outlets of the gas through holes are very evenly distributed on the outlet surface. Compared with the limitation of the heat conduction layer on the inlet surface, the present invention sets the gas through holes to be inclined at a certain angle and sets a part of the outlets below the heat conduction layer, so as to maximize the uniform distribution of the outlets. Since the distribution of gas entering the vacuum reaction chamber is mainly affected by the distribution of the outlets, the gas distribution plate provided by the present invention can greatly improve the distribution uniformity of the reaction gas.

[0094] A groove consisting of only inclined surfaces may be provided on the gas inlet surface of the gas distribution plate. In another embodiment, in order to reduce the height of the gas through hole, the groove may be first recessed downward by a certain distance, and then an inclined bottom surface may be provided to form a V-shaped structure, such as Fig. 9 shown.

[0095] exist Fig. 9 In the cross-sectional schematic diagram of the gas distribution plate shown, the groove 520 is firstly sunken downwardly for a certain distance perpendicular to the gas inlet surface, and then two inclined surfaces 520a and 520b are provided, and a first gas through hole 510a inclined toward the central axis and a second gas through hole 510b inclined away from the central axis are provided on the two inclined surfaces 520a and 520b, respectively. Since it is difficult to make a small-diameter and high-depth hole, the embodiment of the present invention can reduce the depth of the gas through hole, thereby reducing the difficulty and cost of making the gas through hole.

[0096] Fig.10 A schematic cross-sectional view of a gas distribution plate of another embodiment is shown. Fig.10 In the embodiment shown, a gas groove 620 is also provided, and the gas groove is provided with two inclined bottom surfaces 620a and 620b. In order to further reduce the depth of the small-diameter gas through hole, the present invention first makes countersunk holes 630a and 630b with larger diameters on the inclined bottom surface, and then makes small-diameter gas through holes at the bottom of the countersunk holes 630a and 630b. In this embodiment, for the convenience of processing, the countersunk holes 630a and 630b are also small holes with a certain inclination angle. The bottom surfaces of the countersunk holes 630a and 630b need to be provided with a certain inclination angle to facilitate the processing of the first gas through hole 610a and the second gas through hole 610b. In this embodiment, the height of the gas through hole on the gas distribution plate includes the sum of the height of the gas groove, the height of the countersunk hole, and the height of the small-aperture gas through hole. Since the processing difficulty of the groove and the countersunk hole is relatively low, and the height of the small-aperture gas through hole is relatively small, the difficulty of manufacturing the gas through hole on the gas distribution plate is greatly reduced. At the same time, due to the design of the gas groove, the gas uniformity of the gas through holes in the same groove on the gas outlet surface can be greatly improved, thereby improving the uniformity of substrate processing.

[0097] exist Fig.10 In the illustrated embodiment, the countersunk holes and gas through holes on different inclined surfaces in the same groove may be located in pairs in the same radial direction and arranged in parallel, or may be located in different radial directions and staggered by a certain distance.

[0098] exist Fig.11 In the embodiment shown, in order to reduce the difficulty of manufacturing the gas through hole, a countersunk hole with a larger aperture can be firstly manufactured on the gas inlet surface, and the countersunk hole can be set as a first gas countersunk hole 730a and a second gas countersunk hole 730b with a certain inclination angle, and then a first gas through hole 710a and a second gas through hole 710b with a small aperture are set on the inclined bottom surface of the countersunk hole. Since the difficulty of manufacturing the large aperture countersunk hole is greater than the difficulty of manufacturing the first small aperture gas through hole, the difficulty of manufacturing the gas through hole on the gas distribution plate is greatly reduced.

[0099] Since the greater the inclination angle is when processing the gas through holes on the gas distribution plate, the greater the processing difficulty is, therefore, in order to reduce the inclination angle, when two or more circles of gas through holes are set in the same annular gas distribution area, the circle of gas through holes close to the central axis is set to be inclined in the direction of the central axis, and the circle of gas through holes away from the central axis is set to be inclined in the direction away from the central axis. In other embodiments, other settings can be made on the same gas distribution plate as needed. For example, in the edge area of ​​the gas distribution plate, in order to ensure that the gas converges to the central area, the gas through holes in the annular gas distribution area of ​​the edge area can be set to be inclined to the central axis, and the inclination angles can be the same or different.

[0100] In the various embodiments described in the present invention, in order to facilitate the comparison of the distribution of gas through holes on the air inlet surface and the air outlet surface, it is assumed that the gas through holes have the same inclination angle. In actual work, since the distribution of the reaction gas between the upper electrode and the lower electrode is closely related to the distribution of the gas through holes on the air outlet surface, the inclination angle of the gas through holes on the gas distribution plate needs to be set according to actual needs, and can be set to be the same or different.

[0101] In the various embodiments described in the present invention, in order to facilitate the comparison of the distribution of gas holes on the air inlet surface and the air outlet surface, it is assumed that the inclination direction of the gas holes is toward the center of the circle or away from the center of the circle. In actual work, since the distribution of the reaction gas between the upper electrode and the lower electrode is closely related to the distribution of the gas holes on the air outlet surface, the inclination direction of the gas holes on the gas distribution plate needs to be set according to actual needs and can be set to any required direction.

[0102] The output frequency of the RF bias power source applied to the plasma device of the present invention is greater than or equal to 10,000 watts to achieve the processing of a substrate with an etching target layer of greater than or equal to 100 layers, and the aspect ratio of the substrate etched by the present invention is greater than or equal to 40: 1. The output frequency of the RF bias power source selected in the present invention is greater than or equal to 100Khz and less than or equal to 2Mhz.

[0103] In some embodiments, the RF bias power source 74 outputs a pulsed RF bias signal.

[0104] Fig.12 The substrate is obtained by using the plasma device described in the present invention. As can be seen from the figure, by setting the inclined gas through holes, not only the density of the gas through holes on the gas distribution plate is increased, but also the gas flow rate through the gas through holes is reduced, thereby avoiding the gas from the gas through holes being directly sprayed onto the substrate to cause different etching uniformities in different areas. The substrate made by using the gas shower head of the present invention can obtain deep holes or grooves with good morphology and high aspect ratio, meeting the needs of high-precision storage substrates.

[0105] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as a limitation of the present invention. After reading the above content, it will be apparent to those skilled in the art that various modifications and substitutions of the present invention will occur. Therefore, the protection scope of the present invention should be limited by the appended claims.

Claims

1. A gas shower head for a plasma device, the gas shower head comprising a gas distribution plate having an inlet surface and an outlet surface, the gas distribution plate being a disc-shaped structure having a center, comprising a central axis passing through the center and perpendicular to the gas distribution plate, characterized in that: The gas distribution plate includes a plurality of annular gas distribution areas with the circle center as the center; A plurality of gas through holes penetrating the gas inlet surface and the gas outlet surface are arranged on each annular gas distribution area, wherein the gas through holes at least include a plurality of first gas through holes inclined at a certain angle in the radial direction, and the gas through holes further include a plurality of second gas through holes, wherein the second gas through holes are parallel to the central axis or have a different radial inclination direction from the first gas through holes; The plurality of first gas through holes and the plurality of second gas through holes on the same annular gas distribution area form a first circle on the gas inlet surface, and the plurality of first gas through holes and the plurality of second gas through holes on the same annular gas distribution area respectively form a second circle and a third circle on the gas outlet surface; The gases flowing out of the first gas through hole and the second gas through hole in the same annular gas distribution area are separated from each other, so that the distance between the gas outlets of the adjacent gas through holes in the same annular gas distribution area on the gas outlet surface is greater than the distance between the gas inlets on the gas inlet surface, thereby avoiding the generation of a gas curtain; The gas shower head also includes a back plate, which is opposite to the gas inlet surface of the gas distribution plate. After the reaction gas is mixed or evenly distributed in the back plate, it enters the plasma dissociation area between the upper electrode and the lower electrode of the plasma device through the gas through holes on the gas distribution plate.

2. The gas shower head according to claim 1, characterized in that: The gas outlet directions of the plurality of first gas through holes are inclined toward the direction close to the central axis, and the gas outlet directions of the plurality of second gas through holes are inclined toward the direction away from the central axis or are parallel to the central axis.

3. The gas shower head according to claim 1, wherein: The gas outlet directions of the plurality of first gas through holes are inclined away from the central axis, and the gas outlet directions of the plurality of second gas through holes are inclined toward the central axis or are parallel to the central axis.

4. The gas shower head according to claim 1, wherein: In the same annular gas distribution area, the first gas through hole and the second gas through hole have a first radial distance difference from the opening center of the gas inlet surface to the central axis, and the first gas through hole and the second gas through hole in the same gas distribution area have a second radial distance difference from the opening center of the gas outlet surface to the central axis, and the second radial distance difference is greater than the first radial distance difference.

5. The gas shower head according to claim 2, wherein: In the same gas distribution area, the distances from the opening centers of the first gas through holes and the second gas through holes on the gas inlet surface to the central axis are equal, and the first gas through holes and the second gas through holes are alternately arranged.

6. The gas shower head according to claim 4, characterized in that: In the same gas distribution area, the distances from the opening centers of the first gas through holes and the second gas through holes on the gas inlet surface to the central axis are equal, a number of adjacent first gas through holes form a first gas unit, a number of adjacent second gas through holes form a second gas unit, and the first gas units and the second gas units are alternately arranged.

7. The gas shower head according to claim 1, wherein: The gas outlet directions of the plurality of first gas holes are inclined toward the direction approaching the central axis, and the gas outlet directions of the plurality of second gas holes are inclined toward the direction away from the central axis. A plurality of third gas holes are also arranged on the gas distribution plate, and the third gas holes are parallel to the central axis. The first gas holes, the second gas holes and the third gas holes are arranged alternately at intervals.

8. The gas shower head according to claim 1, wherein: The first inclination angle of the first gas through hole and the second inclination angle of the second gas through hole are greater than or equal to 0° and less than 30°.

9. The gas shower head according to claim 1, wherein: An included angle between the first gas through hole and the second gas through hole is greater than or equal to 5°.

10. The gas shower head according to claim 1, wherein: An annular isolation area is arranged between two adjacent annular gas distribution areas, and the annular gas distribution areas and the annular isolation areas are alternately distributed in radial direction.

11. The gas shower head according to claim 10, wherein: The radial width of the annular isolation region is greater than the radial width of the gas distribution region.

12. The gas shower head according to claim 10, wherein: The gas shower head further includes a plurality of heat conduction layers arranged between the back plate and the gas distribution plate.

13. The gas shower head according to claim 12, wherein: The heat conducting layer is disposed on the upper surface of the annular isolation region.

14. The gas shower head according to claim 13, wherein: At least part of the openings of the first gas through holes or the second gas through holes on the gas outlet surface are located within the orthographic projection area of ​​the heat conduction layer on the gas outlet surface of the gas distribution plate.

15. The gas shower head according to claim 1, wherein: The air inlet surface includes a plurality of grooves, each of which has an inclined bottom surface, and the first gas through hole is arranged on the inclined bottom surface of the groove.

16. The gas shower head according to claim 15, wherein: The groove comprises a side wall that is recessed toward the gas outlet surface along the gas inlet surface and an inclined bottom surface that forms a certain angle with the side wall.

17. The gas shower head according to claim 15, wherein: The groove includes two inclined bottom surfaces inclined in different directions, and the two inclined bottom surfaces form a "V"-shaped groove.

18. The gas shower head according to claim 17, wherein: The first gas through hole and the second gas through hole extend perpendicularly to the inclined bottom surface of the groove toward the gas outlet surface.

19. The gas shower head according to claim 15, wherein: A plurality of countersunk holes are arranged in the groove, the countersunk holes are arranged on the inclined bottom surface of the groove, and the openings of the gas through holes are arranged on the inclined bottom surface of the countersunk holes.

20. The gas shower head of claim 1, wherein: A plurality of countersunk holes are arranged on the air inlet surface, each of the countersunk holes has an inclined bottom surface, and the opening of the gas through hole is arranged on the inclined bottom surface of the countersunk hole.

21. A plasma device, comprising a vacuum reaction chamber, characterized in that: The vacuum reaction chamber is provided with: A base, used to support the substrate to be processed; A gas shower head, arranged opposite to the base, and used for providing reaction gas into the vacuum reaction chamber; A radio frequency source power source, used to dissociate the reaction gas to generate plasma; a radio frequency bias power source, applied to the base, for driving charged particles in the plasma to process the substrate; The gas shower head has the features as claimed in claim 1.

22. The plasma device according to claim 21, characterized in that: The output frequency of the radio frequency bias power source is greater than or equal to 10,000 watts.

23. The plasma device according to claim 21, characterized in that: The depth-to-width ratio of the substrate etching is greater than or equal to 40:

1.

24. The plasma device according to claim 21, characterized in that: The etching target layer of the substrate is greater than or equal to 100 layers.

25. The plasma device according to claim 21, characterized in that: The output frequency of the radio frequency bias power source is greater than or equal to 100Khz and less than or equal to 2Mhz.

26. The plasma device according to claim 21, characterized in that: The radio frequency bias power source outputs a pulsed radio frequency bias signal.

27. The plasma device according to claim 21, characterized in that: The gas pressure in the reaction chamber is less than or equal to 100 mTorr.

28. A method for manufacturing the gas shower head as claimed in claim 1, characterized in that: The steps include: A disc-shaped gas distribution plate is provided, wherein the gas distribution plate comprises a gas inlet surface, a gas outlet surface and a central axis perpendicular to the gas distribution plate. A plurality of annular gas distribution areas are arranged on the gas distribution plate, and a plurality of first gas through holes with a first inclination angle and a plurality of second gas through holes with a second inclination angle are arranged in each of the gas distribution areas, wherein the gas outlet direction of the plurality of first gas through holes is inclined toward the direction close to the central axis, and the gas outlet direction of the plurality of second gas through holes is inclined toward the direction away from the central axis.

29. The method of claim 28, wherein: A plurality of annular grooves are formed on the gas inlet surface of the gas distribution plate, wherein the annular grooves have at least one inclined bottom surface; The angle between the inclined bottom surface and the air inlet surface is 0°-30°, and the first gas through hole and the second gas through hole are arranged perpendicular to the inclined bottom surface.

30. The method of claim 29, wherein: When making the groove, firstly, a concave portion with a certain depth is made perpendicular to the air inlet surface and toward the air outlet surface, and then an inclined bottom surface is made on the bottom surface of the concave portion.

31. The method of claim 29, wherein: A plurality of countersunk holes are arranged on the inclined bottom surface, and the air inlet of the gas through hole is arranged at the bottom of the countersunk hole.

32. The method of claim 31, wherein: The diameter of the counterbore is greater than the diameter of the gas through hole.

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