Electrostatic chucking plate for improving etching uniformity

Abstract

The application provides an electrostatic chucking disc for improving etching uniformity, comprising a surface layer, an intermediate layer and a base, the intermediate layer has two independent temperature control zones, namely a center zone and an edge zone, wherein the center zone is a central circular area corresponding to the center part of the wafer, and the edge zone is a peripheral annular area corresponding to the peripheral edge area of the wafer. The electrostatic chucking disc originally unable to support the center / edge independent temperature control is changed to support the center / edge independent temperature control, and the problem of in-plane etching uniformity deterioration caused by the thinning of the edge of the focus ring is compensated by adjusting the edge temperature when the cavity is high in time.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and more specifically to an electrostatic adsorption disk for improving etching uniformity. Background Technology

[0002] As wafer sizes increase, higher demands are placed on the etching uniformity of the reaction process chamber. In order to ensure uniformity within the etched wafer, mainstream dry etching chambers incorporate a focusing ring around the wafer, typically made of a material similar to the surface material of the wafer to be etched.

[0003] The focusing ring is located at the edge of the electrostatic adsorption disk. During the etching process, as the cavity RF increases, the focusing ring will gradually wear down, resulting in the focusing ring becoming thinner and the edge etching rate increasing. During one MTBC (etching process between two cleaning cycles), the etching rate changes are different between the inner and outer rings (central and edge regions) of the wafer. The etching rate of the inner ring remains basically unchanged, while the etching rate of the outer ring increases rapidly, resulting in poor cavity etching uniformity. Summary of the Invention

[0004] In view of the shortcomings of the prior art described above, the purpose of this application is to provide an electrostatic adsorption disk that improves etching uniformity, in order to solve the problem that the uniformity of cavity etching deteriorates as the cavity RF increases in the prior art.

[0005] To achieve the above and other related objectives, this application provides an electrostatic adsorption disk for improving etching uniformity, comprising a surface layer, an intermediate layer and a base. The intermediate layer has two independent temperature control zones, namely a central zone and an edge zone. The central zone is a central circular area corresponding to the center of the wafer, and the edge zone is an outer ring area corresponding to the outer edge of the wafer.

[0006] Preferably, the heating coil in the central area is a concentric circle winding, and the heating coil in the edge area is a ring winding.

[0007] Preferably, the two sets of heating coils are completely insulated from each other and do not conduct electricity, and the heating power, start / stop and temperature rise slope are set separately.

[0008] Preferably, the space between the two sets of heating coils is filled with heat-insulating ceramic filler.

[0009] Preferably, an electrostatic adsorption electrode for holding the wafer is embedded inside the surface layer.

[0010] Preferably, the electrostatic adsorption electrode is used for zoned adsorption voltage control according to the above two independent temperature control zones.

[0011] Preferably, the base is provided with two independent and non-interconnected cooling channels.

[0012] Preferably, a metal isolation rib is set between the two cooling channels, and a vacuum insulation micro-gap is reserved.

[0013] As described above, the electrostatic adsorption disk for improving etching uniformity provided in this application has the following beneficial effects: it transforms the electrostatic adsorption disk, which originally could not support individual temperature control of the center / edge, into one that can support individual temperature control of the center / edge, and compensates for the problem of poor etching uniformity in the wafer surface caused by the thinning of the focus ring edge when the cavity has high hours by adjusting the edge temperature. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0015] Figure 1 The graph shows the comparison between the temperature of the electrostatic adsorption disk and the etching rate. Figure 2 The diagram shows a temperature control zone of an electrostatic adsorption disk for improving etching uniformity, as provided in an embodiment of this application. Detailed Implementation

[0016] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. This application can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this invention.

[0017] The technical solutions of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0018] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," indicating orientation or positional relationships, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0019] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components; and they can refer to a wireless connection or a wired connection. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0020] Furthermore, the technical features involved in the different embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0021] like Figure 1 As shown, the inventors discovered through experiments that the temperature of the electrostatic adsorption disk (ESC) is directly proportional to the etching rate (ER). Lowering the temperature of the edge area of ​​the electrostatic adsorption disk can reduce the edge etching rate. However, the electrostatic adsorption disk used in the machine is a temperature control integrated design, which cannot support separate temperature control of the center / edge to compensate for the differences in the wafer surface.

[0022] To address this issue, this application provides an electrostatic adsorption disk that improves etching uniformity.

[0023] Please see Figure 2 It shows a schematic diagram of the temperature control zone of the electrostatic adsorption disk for improving etching uniformity provided in the embodiments of this application.

[0024] like Figure 2 As shown, the electrostatic adsorption disk 1 for improving etching uniformity has two independent temperature control zones, namely the center zone and the edge zone. The center zone is a central circular area corresponding to the center of the wafer, and the edge zone is an outer ring area corresponding to the outer edge of the wafer.

[0025] The electrostatic adsorption tray 1 is divided into a surface layer, a middle layer and a base from top to bottom. The surface layer has an embedded electrostatic adsorption electrode for holding the wafer. The middle layer is a dual-zone isolated heating layer with two independent temperature control zones. The base has two independent and non-interconnected cooling channels.

[0026] The electrostatic adsorption electrode can be selected to perform zoned adsorption voltage control according to the two independent temperature control zones mentioned above, and further optimize the uniformity of heat transfer in wafer bonding in conjunction with temperature control.

[0027] The heating coil in the central area is a concentric circle winding, while the heating coil in the edge area is a toroidal winding. The two sets of heating coils are completely insulated from each other and do not conduct electricity. Each set has its own independent power supply cable, and the heating power, start / stop, and temperature rise rate can be set separately. The space between the two sets of heating coils is filled with heat-insulating ceramic filler to block lateral heat conduction.

[0028] Metal isolation ribs are set between the two cooling channels, and vacuum insulation micro gaps are reserved to significantly reduce the lateral heat conduction between the central area and the edge area.

[0029] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of this application. Therefore, the drawings only show the components related to this invention and are not drawn according to the actual number, shape and size of the components. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0030] In summary, the electrostatic adsorption disk for improving etching uniformity provided in this application transforms the original electrostatic adsorption disk, which could not support independent temperature control at the center and edge, into one that can. At high cavity clock speeds, adjusting the edge temperature compensates for the reduced etching uniformity within the wafer surface caused by the thinning of the focusing ring edge. Therefore, this application effectively overcomes the various shortcomings of the prior art and has high industrial applicability.

[0031] The above embodiments are merely illustrative of the principles and effects of this application and are not intended to limit this application. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this application. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this invention should still be covered by the claims of this application.

Claims

1. An electrostatic adsorption disk for improving etching uniformity, characterized in that, The electrostatic adsorption disk includes a surface layer, an intermediate layer, and a base. The intermediate layer has two independent temperature control zones, namely a central zone and an edge zone. The central zone is a central circular area corresponding to the center of the wafer, and the edge zone is an outer ring area corresponding to the outer edge of the wafer.

2. The electrostatic adsorption disk according to claim 1, characterized in that, The heating coil located in the central area is a concentric circle winding, and the heating coil located in the edge area is a ring winding.

3. The electrostatic adsorption disk according to claim 2, characterized in that, The two sets of heating coils are completely insulated from each other and do not conduct electricity. The heating power, start / stop, and temperature rise slope are set respectively.

4. The electrostatic adsorption disk according to claim 2, characterized in that, The space between the two sets of heating coils is filled with heat-insulating ceramic filler.

5. The electrostatic adsorption disk according to claim 1, characterized in that, An electrostatic adsorption electrode for holding the wafer is embedded inside the surface layer.

6. The electrostatic adsorption disk according to claim 5, characterized in that, The electrostatic adsorption electrode is controlled by partitioned adsorption voltage according to the two independent temperature control zones.

7. The electrostatic adsorption disk according to claim 1, characterized in that, The base is equipped with two independent and non-interconnected cooling channels.

8. The electrostatic adsorption disk according to claim 7, characterized in that, Metal isolation ribs are installed between the two cooling channels, and vacuum insulation micro-gaps are reserved.

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