Plasma etching apparatus and its upper electrode assembly

Abstract

The application discloses a plasma etching device and an upper electrode assembly thereof. The upper electrode assembly comprises a substrate, an air inlet and a connecting end, the air inlet is connected with a power supply, and at least two levels of gas introduction layers are arranged. The gas introduction layers are nested with each other and connected with the substrate. Each level of the gas introduction layer covers the air inlet, and a gas flow space is reserved between adjacent levels of the gas introduction layers to introduce the reaction gas in stages. Each level of the gas introduction layer is provided with at least one protruding part, and the surface of the protruding part is provided with a gas hole to disperse the reaction gas introduced by itself. The protruding part in each level of the gas introduction layer can first gather and disperse the introduced gas, thereby improving the concentration uniformity of the gas introduced into the reaction chamber. The gas introduced into the reaction chamber based on the above mode can improve the concentration uniformity of the plasma, thereby improving the product yield of the semiconductor device.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor device manufacturing, and more particularly to a plasma etching device and an upper electrode assembly thereof. BACKGROUND

[0002] In the process of preparing semiconductor devices, plasma etching technology is often used to prepare trench, channel and other characteristic structures.

[0003] In the process of preparing 3D memory devices, as the storage density of 3D memory devices increases, the number of stacked layers of the stack structure increases, making the aspect ratio of the trench or channel that penetrates or partially etches the stack structure larger and larger. The etching process becomes more and more demanding when preparing characteristic structures with the above characteristics. On the one hand, the number of stacked layers in 3D memory devices has increased dramatically, making the process indicators more demanding and the process window much smaller. On the other hand, when using existing etching technology, the defects of poor uniformity of some indicators of the wafer level to be processed are increasingly prominent. SUMMARY

[0004] In view of the above problems, the purpose of the present application is to provide an improved plasma etching device and an upper electrode assembly thereof. The reaction gas is introduced by the upper electrode assembly to improve the uniformity of the gas concentration introduced into the reaction chamber, thereby improving the uniformity of the plasma concentration in the reaction chamber, and improving the wafer uniformity of the 3D memory device prepared by the above etching device, thereby improving the yield of the 3D memory device.

[0005] According to a first aspect of the present application, an upper electrode assembly for a plasma etching device is provided, comprising:

[0006] a substrate comprising a gas inlet and a connection end, the gas inlet being open to a reaction gas, and the connection end being electrically connected to a power supply;

[0007] at least two levels of gas introduction layers, each level of gas introduction layers being nested with each other and connected to the substrate, each level of gas introduction layers covering the gas inlet, and a gas flow space being reserved between adjacent levels of gas introduction layers to introduce the reaction gas in stages,

[0008] wherein each level of gas introduction layers is provided with at least one protruding portion, and the surface of the protruding portion is provided with a gas passage hole to disperse the reaction gas introduced by itself.

[0009] Optionally, each level of gas introduction layers comprises:

[0010] a bottom plate comprising a plurality of gas passage holes and having at least one protruding portion; and

[0011] a side wall connected to the substrate at one end and connected to the bottom plate at the other end.

[0012] Optionally, the number of the protrusions in the gas introduction layer increases exponentially.

[0013] Optionally, the number of the protrusions in the gas introduction layer increases exponentially.

[0014] Optionally, the protrusions in the gas introduction layer are arranged around the protrusions in the previous gas introduction layer to disperse the reaction gas introduced by the protrusions in the previous gas introduction layer.

[0015] Optionally, the protrusions in the gas introduction layer including at least two protrusions are uniformly distributed, and / or the protrusions in the gas introduction layer including one protrusion are located in the central region of the bottom plate.

[0016] Optionally, the first gas introduction layer includes one protrusion located in the central region of the bottom plate, or includes at least two protrusions arranged around the central region of the bottom plate and equidistant from the center.

[0017] Optionally, the third gas introduction layer includes four protrusions, and every two adjacent protrusions are symmetrically arranged based on the protrusions in the first or second gas introduction layer.

[0018] Optionally, the third gas introduction layer includes four protrusions, and every two adjacent protrusions are symmetrically arranged based on the protrusions in the first or second gas introduction layer.

[0019] Optionally, the bottom plates in each gas introduction layer are the same shape, and the centers of the bottom plates are vertically projected to coincide.

[0020] Optionally, the density of the gas holes on the protrusions is greater than or equal to the density of the gas holes in other regions of the bottom plate connected to the protrusions.

[0021] Optionally, the gas holes in other regions of the bottom plate connected to the protrusions are uniformly distributed.

[0022] Optionally, the protrusions in each gas introduction layer are conical in shape.

[0023] Optionally, the sizes of the protrusions in each gas introduction layer are equal, and the heights of the protrusions in each gas introduction layer are gradually decreased, and / or the diameters of the protrusion bottom surfaces in each gas introduction layer are gradually decreased.

[0024] Optionally, the heights of the protrusions in each gas introduction layer are gradually decreased by a multiple, and / or the diameters of the protrusion bottom surfaces in each gas introduction layer are gradually decreased by a multiple.

[0025] Optionally, the distance between the gas introduction layer and the substrate is a sum of the height of the protrusion in the upper gas introduction layer, the distance between the upper gas introduction layer and the substrate, and a correction factor.

[0026] The distance between the gas introduction layer and the substrate refers to a distance between other areas connected with the protrusions in the gas introduction layer and a connecting surface between the substrate and the gas introduction layer.

[0027] According to a second aspect of the present application, a plasma etching device is provided, comprising:

[0028] a cavity surrounding a reaction chamber;

[0029] an upper electrode assembly as described above, at least partially located in the reaction chamber, and configured to introduce a reaction gas into the reaction chamber;

[0030] a lower electrode located in the reaction chamber and arranged opposite to the upper electrode assembly, and

[0031] a supporting platform located between the upper electrode assembly and the lower electrode, and configured to support a semiconductor structure to be etched.

[0032] Optionally, the plasma etching device is a capacitively coupled plasma etching device.

[0033] The plasma etching device and the upper electrode assembly thereof provided in the present application can improve the uniformity of the concentration of the reaction gas introduced into the reaction chamber by introducing the reaction gas into the reaction chamber through at least two gas introduction layers. Further, the protrusions in each gas introduction layer can better improve the uniformity of the concentration of the reaction gas introduced into the reaction chamber by first gathering and then dispersing the introduced gas. Furthermore, the gas introduced into the reaction chamber based on the above method can improve the uniformity of the concentration of the plasma, and thus improve the uniformity of the wafer level after etching. Moreover, the feature structure obtained by etching based on the above etching device can increase the window of the subsequent process in the semiconductor device, and improve the yield of the semiconductor device. BRIEF DESCRIPTION OF DRAWINGS

[0034] The above and other objects, features and advantages of the present application will become more apparent from the following description of embodiments of the present application taken in conjunction with the accompanying drawings, in which:

[0035] Figure 1 A structure diagram of a plasma etching device according to the first embodiment of the present application is shown.

[0036] Figure 2 A perspective structure diagram of an upper electrode assembly in the plasma etching device according to the first embodiment of the present application is shown.

[0037] Figure 3 An exploded view of the upper electrode assembly in the plasma etching device according to the first embodiment of the present application is shown.

[0038] Figure 4 An exploded view of the upper electrode assembly in the plasma etching device according to the second embodiment of the present application is shown. DETAILED DESCRIPTION

[0039] The present application will be described in more detail by referring to the attached drawings. Like elements are denoted by like reference numerals throughout the various figures. Individual parts in the figures are not drawn to scale for the sake of clarity. Moreover, certain known elements can not be shown. For the sake of simplicity, a semiconductor structure obtained after several steps can be described in one figure.

[0040] It should be understood that when a layer, a region is referred to as being "on" or "above" another layer, another region, it can be directly on the other layer, the other region or intervening layers or regions can also be present. In this context, "directly on" or "directly above" will be used to refer to a layer, a region that is immediately on the other layer, the other region.

[0041] In this application, the term "semiconductor structure" refers to a collective term for the entire semiconductor structure formed at various steps in the fabrication of a memory device, including all layers or regions that have been formed. Many specific details of the present application are described below in order to provide a thorough understanding of the present application. However, as will be understood by those skilled in the art, the present application can be practiced without

[0042] In the preparation of channel holes, top selection gate trenches and other structures in 3D memory devices, the concentration distribution of the reaction gas introduced into the etching device is improved, and the concentration distribution and the incident angle distribution of the plasma are improved under the excitation of the power supply, so that the stability of some parameters from the wafer center to the wafer edge is better. Although the wafer edge has always been the focus of research on the yield improvement of semiconductor devices, the difference between the wafer center and the wafer edge needs to be effectively overcome at the beginning of process equipment and process research. The plasma etching device provided in the application improves the uniformity of the introduced reaction gas concentration, so that the plasma concentration at the wafer center, the plasma concentration at the wafer center, and the plasma concentration at the wafer edge are closer, thereby improving the uniformity of the plasma concentration in the etching device.

[0043] The present application can be presented in various forms, some examples of which will be described below.

[0044] Figure 1 The structure of the plasma etching device provided by the first embodiment of the application is shown. Figure 2 The structure of the plasma etching device provided by the first embodiment of the application is shown. Figure 3 The structure of the plasma etching device provided by the first embodiment of the application is shown.

[0045] As Figure 1 The plasma etching device 1000 is illustrated by taking a capacitively coupled plasma etching device as an example. The plasma etching device 1000 includes a reaction chamber, an upper electrode assembly 100, a lower electrode 300, and a bearing platform 400.

[0046] The reaction chamber is formed by a cavity 200, which includes a top, a bottom and a sidewall, and the reaction chamber is in a vacuum environment. The upper electrode assembly 100 is at least partially located in the reaction chamber and is used to introduce reaction gas into the reaction chamber. The lower electrode 300 is located in the reaction chamber and is arranged opposite to the upper electrode assembly 100. A radio frequency power supply (not shown in the figure) is loaded to the upper electrode assembly 100 and the lower electrode 300, and a high frequency electric field is generated in the reaction chamber. Then the initial electrons in the reaction chamber obtain energy under the action of the radio frequency electric field, bombard the reaction gas to ionize it, generate more electrons, ions and neutral radicals, and then form a dynamic equilibrium plasma.

[0047] The bearing platform 400 is used to place the semiconductor device 500 to be processed (a semiconductor structure device in the manufacturing process before the formation of a high aspect ratio feature structure). The bearing platform 400 can be a flat plate or a clamp.

[0048] In the process of etching semiconductor structure device to prepare high aspect ratio feature structure (for example, channel hole in 3D memory device, top select gate trench), the plasma etching device 1000 introduces reaction gas into the reaction chamber through the upper electrode assembly 100 to improve the uniformity of the gas concentration. Further, the plasma etching device 1000 generates plasma under the action of the electric field formed in the reaction chamber, and the plasma concentration at the center of the semiconductor device 500 to be processed, the plasma concentration in the middle region of the semiconductor device 500, and the plasma concentration in the edge region of the semiconductor device 500 are close to equal. Further, the semiconductor device 500 is etched by using the above-mentioned plasma etching device 1000 to form channels and trenches that fully or partially penetrate the stack structure, which can better improve the yield of the semiconductor device.

[0049] In combination with Figure 2 , Figure 3 , the upper electrode assembly 100 that can introduce reaction gas in stages is shown. The upper electrode assembly 100 includes a substrate 110 and at least two stages of gas introduction layers. The substrate 110 includes a gas inlet and a connection end (not shown in the figure), the gas inlet is connected to the reaction gas provided from the outside, and the connection end is electrically connected to the power supply to form an electric field to generate plasma. Each stage of the at least two stages of gas introduction layers is nested with each other and connected to the substrate 110, each stage of the gas introduction layers covers the gas inlet on the substrate 110, and a gas flow space is reserved between adjacent stages of the gas introduction layers to introduce the reaction gas introduced by the gas inlet into the reaction chamber in stages. Further, each stage of the gas introduction layers is provided with at least one protrusion, and the surface of the protrusion is provided with a gas passage to disperse the reaction gas introduced by itself, thereby achieving the purpose of improving the uniformity of the introduced reaction gas concentration.

[0050] Further, as shown in Figure 2 , each stage of the gas introduction layers (gas introduction layer 120, gas introduction layer 130, gas introduction layer 140) includes a bottom plate and a side wall. The bottom plate is provided with a plurality of gas passages 150, and the bottom plate of each stage of the gas introduction layers has at least one protrusion. Specifically, the bottom plate includes other regions and protrusions connected to the other regions, wherein the protrusions protrude away from the substrate 110 on the side of the surface of the other regions, and each protrusion is provided with a gas passage 150. Further, a small part of the other regions connected to the protrusions is curved in a downward arc, and the remaining other regions are flat. One end of the side wall is connected to the substrate 100, and the other end is connected to the bottom plate.

[0051] Further, the number of stages of the gas introduction layers is the order in which the reaction gas introduced from the gas inlet of the substrate 110 is introduced by the gas introduction layers, and the number of protrusions in the gas introduction layers increases gradually. Further, the number of protrusions in the gas introduction layers increases exponentially.

[0052] Furthermore, the protrusions in the gas inlet layer are dispersed around the protrusions in the previous gas inlet layer to disperse the reactive gas introduced by the protrusions in the previous gas inlet layer.

[0053] Furthermore, the protrusions in the gas inlet layer, which includes at least two protrusions, are evenly distributed, and / or the protrusions in the gas inlet layer, which includes one protrusion, are located in the central region of its own base plate.

[0054] Furthermore, the first-stage gas introduction layer (the gas introduction layer directly facing the substrate 110, which is also the gas introduction layer in which the reaction gas introduced from the air inlet is introduced for the first time) in the upper electrode assembly 100 includes a protrusion located in the central region of its own base plate, or includes at least two protrusions arranged around the central region of its own base plate and equidistant from each other.

[0055] like Figure 3 The diagram illustrates the structure of an upper electrode assembly 100. The upper electrode assembly 100 includes three gas inlet layers. The first-stage gas inlet layer 120 has one protrusion 121 located in the central region of its base plate. The second-stage gas inlet layer 130 includes two protrusions 131 arranged equidistant from the center of its base plate. The third-stage gas inlet layer 140 includes four protrusions 141, with each pair of adjacent protrusions symmetrically arranged based on either the protrusions in the first-stage gas inlet layer 120 or the second-stage gas inlet layer 130.

[0056] Furthermore, the base plates in each gas introduction layer have the same shape, and the projections of the centers of each base plate in the vertical direction coincide. For example, the base plate of each gas introduction layer is circular, like a wafer. The density of vent holes 150 on the protrusions in each gas introduction layer is greater than or equal to the density of vent holes in other regions connected to the protrusions in the base plate itself. The vent holes 150 in the other regions connected to the protrusions in the base plate are uniformly distributed, and further, the vent holes 150 in the other regions connected to the protrusions in the base plate are arranged in a concentric circular array.

[0057] Specifically, the protrusions 131 in the second stage gas introduction layer 130 are located on the same diameter of the bottom plate of the second stage gas introduction layer 130 and are equidistant from the center of the bottom plate of the second stage gas introduction layer 130. The protrusions 141 in the third stage gas introduction layer 140 are located on the same diameter of the bottom plate of the third stage gas introduction layer 140, and two protrusions 141 located on the same side of the center of the third stage gas introduction layer 140 are symmetrically arranged based on one protrusion 131 in the second stage gas introduction layer 130, and two protrusions 141 located on different sides of the center of the third stage gas introduction layer 140 and closest to the center of the third stage gas introduction layer 140 are symmetrically arranged based on the center of the first stage gas introduction layer 120 (the protrusion 121 in the first stage gas introduction layer 120). Further, the diameter on which the protrusions 131 in the second stage gas introduction layer 130 are located coincides with the projection of the diameter on which the protrusions 141 in the third stage gas introduction layer 140 are located in the vertical direction.

[0058] Further, the shape of the protrusions in each stage gas introduction layer is conical. Further, the size of the protrusions in each stage gas introduction layer is equal, and the height of the protrusions in each stage gas introduction layer decreases step by step, and / or the diameter of the bottom surface of the protrusions in each stage gas introduction layer decreases step by step. Specifically, the height of the protrusions in each stage gas introduction layer decreases step by step in multiples, and / or the diameter of the bottom surface of the protrusions in each stage gas introduction layer decreases step by step in multiples.

[0059] Further, the distance between the gas introduction layer and the substrate 110 is the sum of the height of the protrusions in the upper stage gas introduction layer, the distance between the upper stage gas introduction layer and the substrate 110, and a correction factor. Wherein, the distance between each stage gas introduction layer and the substrate 110 refers to the distance between the flat surface of the other area connected to the protrusions in the gas introduction layer and the connecting surface between the substrate 110 and the gas introduction layer.

[0060] The upper electrode assembly 100 in the embodiment introduces the reaction gas into the reaction chamber through the three-stage gas introduction layers. Wherein, part of the reaction gas introduced by the first stage gas introduction layer 120 is gathered by the protrusions 121 and then dispersedly introduced. The protrusions 131 in the second stage gas introduction layer 130 dispersively introduce at least most of the reaction gas introduced by the protrusions 121 into the next stage gas introduction layer. Further, the protrusions 141 in the third stage gas introduction layer 130 dispersively introduce at least most of the reaction gas introduced by the protrusions 131 into the reaction chamber, so as to improve the uniformity of the concentration of the reaction gas introduced into the reaction chamber.

[0061] Figure 4 An exploded view of the upper electrode assembly in the plasma etching device according to the second embodiment of the present application is shown.

[0062] The plasma etching device provided by the second embodiment replaces the upper electrode assembly 100 with the upper electrode assembly 800 on the basis of the plasma etching device 1000. As shown in FIG. 8, the upper electrode assembly 800 includes a first stage gas introduction layer 820, a second stage gas introduction layer 830, and a third stage gas introduction layer 840. Figure 4As shown, the upper electrode assembly 800 includes a substrate 810 and two-stage gas introduction layers. The substrate 110 includes a gas inlet through which a reaction gas is supplied from outside and a connection end electrically connected to a power source to form an electric field for generating plasma. The bottom plates in each stage of the gas introduction layers have the same shape, and the projections of the centers of the bottom plates in the vertical direction coincide. For example, the bottom plate of each stage of the gas introduction layers is circular like a wafer. The density of the gas holes 850 on the projection in each stage of the gas introduction layers is greater than or equal to the density of the gas holes in other regions of the bottom plate connected to the projection. The gas holes 850 in the other regions of the bottom plate connected to the projection are uniformly distributed, and further, the gas holes 850 in the other regions of the bottom plate connected to the projection are arranged in a concentric circular array.

[0063] Further, the first stage gas introduction layer 820 is directly connected to the substrate 810 and covers the gas inlet. The second stage gas introduction layer 830 covers the first stage gas introduction layer 820 and is connected to the substrate 810. The first stage gas introduction layer 820 has one projection 821 located in the center region of the bottom plate, and the second stage gas introduction layer 830 includes a plurality of projections 831 arranged around the center region of the bottom plate and equidistant from the center. The plurality of projections 831 are uniformly distributed. Specifically, the second stage gas introduction layer 830 has four uniformly distributed projections 831, for example, the four projections 831 form a circle with the center of the bottom plate as the center, and the circle is divided into four uniform circular arcs.

[0064] The upper electrode assembly 800 in the embodiment introduces the reaction gas into the reaction chamber through two-stage gas introduction layers. The reaction gas introduced by the first stage gas introduction layer 820 is gathered by the projection 821 and then dispersed. The projection 831 of the second stage gas introduction layer 830 uniformly disperses at least most of the reaction gas introduced by the projection 821 into the reaction chamber to improve the uniformity of the concentration of the reaction gas introduced into the reaction chamber.

[0065] It should be noted that the number of gas introduction layers in the upper electrode assembly, the number of projections of each gas introduction layer, and the distribution method can be adjusted according to actual needs.

[0066] The above describes embodiments of the present application. However, these embodiments are only for illustrative purposes, and are not intended to limit the scope of the present application. The scope of the present application is defined by the appended claims and their equivalents. Without departing from the scope of the present application, those skilled in the art can make various substitutions and modifications, which should fall within the scope of the present application.

Claims

1. An upper electrode assembly for a plasma etching apparatus, comprising: The application relates to a substrate for a plasma display panel, which comprises an inlet for a reaction gas and a connection for a power supply; at least two gas introduction layers, each of which is nested with the other and connected to the substrate, and each of which covers the inlet for the reaction gas, and each of which has a gas flow space between adjacent gas introduction layers to introduce the reaction gas in stages, the first gas introduction layer being directly connected to the substrate and covering the inlet, and the second gas introduction layer covering the first gas introduction layer and being connected to the substrate. Each gas introduction layer comprises a base plate, a plurality of gas holes, and at least one protrusion, the surface of the protrusion being provided with gas holes to disperse the reaction gas introduced by the protrusion, the density of the gas holes on the protrusion being greater than or equal to the density of the gas holes in the other regions of the base plate connected to the protrusion, the number of the protrusions in the gas introduction layer increasing in stages, and the order of the gas introduction layers being the order in which the reaction gas is introduced by the gas introduction layers after being introduced from the inlet. Each gas introduction layer further comprises: a side wall connected to the substrate at one end and to the base plate at the other end.

2. The upper electrode assembly of claim 1, wherein The number of the protrusions in the gas introduction layer increases exponentially in stages. The protrusions in the gas introduction layer are arranged around the protrusions in the previous gas introduction layer to disperse the reaction gas introduced by the protrusions in the previous gas introduction layer.

3. The upper electrode assembly of claim 1, wherein The protrusions in the gas introduction layer comprising at least two protrusions are uniformly distributed, and / or the protrusion in the gas introduction layer comprising one protrusion is located in the central region of the base plate.

4. The upper electrode assembly of claim 1, wherein The first gas introduction layer comprises one protrusion located in the central region of the base plate, or comprises at least two protrusions arranged around the central region of the base plate and equidistant from the center.

5. The upper electrode assembly of claim 4, wherein The third gas introduction layer comprises four protrusions, and each two adjacent protrusions are symmetrically arranged based on the protrusions in the first or second gas introduction layer.

6. The upper electrode assembly of claim 5, wherein, The second gas introduction layer comprises a plurality of protrusions arranged around the central region of the base plate and equidistant from the center.

7. The upper electrode assembly of claim 1, wherein The base plates in each gas introduction layer are identical in shape, and the projections of the centers of the base plates in the vertical direction coincide.

8. The upper electrode assembly of claim 1, wherein The gas holes in the other regions of the base plate connected to the protrusions are uniformly distributed.

9. The upper electrode assembly of claim 2, wherein, The protrusions in each gas introduction layer are conical in shape.

10. The upper electrode assembly of claim 1, wherein The sizes of the protrusions in each gas introduction layer are equal, and the heights of the protrusions in each gas introduction layer decrease in stages, and / or the diameters of the bottom surfaces of the protrusions in each gas introduction layer decrease in stages.

11. The upper electrode assembly of claim 1, wherein ​ 12. The upper electrode assembly of claim 11, wherein, ​ 13. The upper electrode assembly of claim 1, wherein The height of the protrusions in the gas introduction layers decreases by a factor from one layer to the next, and / or the diameter of the protrusion base in the gas introduction layers decreases by a factor from one layer to the next.

14. The upper electrode assembly of claim 12, wherein, The distance between the gas introduction layer and the substrate is the sum of the height of the protrusions in the previous gas introduction layer, the distance between the previous gas introduction layer and the substrate, and a correction factor, The distance between the gas introduction layer and the substrate refers to the distance between the other areas connected to the protrusions in the gas introduction layer and the connecting surface between the substrate and the gas introduction layer.

15. A plasma etching apparatus, characterized by comprising: Comprise: A cavity is formed around the reaction chamber; The upper electrode assembly of any one of claims 1-14 is at least partially located in the reaction chamber and is used to introduce a reaction gas into the reaction chamber; A lower electrode is located in the reaction chamber and is arranged opposite to the upper electrode assembly, and A carrying platform is located between the upper electrode assembly and the lower electrode and is used to carry a semiconductor structure to be etched.

16. The plasma etching apparatus of claim 15, wherein, The plasma etching device is a capacitively coupled plasma etching device.

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