Patent Application
20190341280
This non-provisional application claims priority under 35 U.S.C. § 119(a) on Patent Application No(s). 201810413913.4 filed in China on May 3, 2018, the entire contents of which are hereby incorporated by reference.
The present invention relates to a wafer pedestal of a semiconductor processing chamber, especially to a pedestal provided with multiple heating zones and a reaction chamber including the same.
Among the semiconductor processing equipment, a reaction chamber is a processing chamber includes a pedestal used for supporting a wafer to perform various processes, such as etching process. During some processes involving gas reaction, there is a high demand to maintain a proper wafer temperature. Based on the demand, the pedestal is properly designed and can be served as a heater with thermal control means that is able to precisely maintain the wafer temperature during processes. In general, the heater includes a plate made of ceramic or metal and heating elements sealed in the plate, like heating coils. More specific, the heater may further include other electronic elements such as thermal sensors and a thermal controller.
Said heater plays a key role in many wafer processes (e.g. CVD, PECVE, Optical lithography, etching and cleaning) since the operation of thermal control affects the process of chemical reaction. For example, reaction gas is distributed and deposited onto the reaction surface of the wafer to form a conductive layer or an insulation layer. Said thermal control is a significant approach to obtain a deposition thin film on the wafer with a uniform thickness and fine quality,
A known prior art disclosed in a reference (CN101807515A) is a heater having multiple heating zones, which includes a plate having plural resistive heating elements. Each heating element is configured to produce a particular amount of heat and shaped to fit the corresponding one of the heating zones defined on the plate. The temperature over plate could be maintained to a uniform value by properly controlling the line width and power supply for each of heating elements. In general, heat transfers according to a thermal gradient established in the plate. In the case where the plate includes plural heating elements operated at different levels of heating processes, the complicated heat transfer may become an issue, particularly in a lateral transfer, which will probably affect the required heating duration and the temperature uniformity over the heater.
In view of the background of thermal control as mentioned above, there is a demand in the semiconductor manufacture field to develop a wafer pedestal with multiple heating zones and a preferred heat transferring confinement mechanism.
An objective of the present invention is to provide a wafer pedestal including a plate having a top, a bottom opposite to the top and a thickness extending between the top and the bottom, the plate defining a central axis; a heating assembly embedded in the plate; and a thermal insulation assembly embedded in the plate at a radial position, the plate being divided into a first heating zone and a second heating zone based on the radial position.
In one preferred embodiment, the plate has at least one groove extending from the bottom toward the top, the thermal insulation assembly is inserted into the at least one groove.
In one preferred embodiment, the thermal insulation assembly is sealed in the plate.
In one preferred embodiment, the heating assembly includes plural thermal conductive elements extending between the top and the bottom.
In one preferred embodiment, at least a portion of the thermal conductive elements passes through at least a portion of the thermal insulation assembly.
In one preferred embodiment, the thermal insulation assembly has at least one cutout surrounding a portion of the thermal conductive elements.
In one preferred embodiment, the heating assembly includes a first thermal conductive element and a second thermal conductive element extending between the top and the bottom of the plate, wherein the first thermal conductive element is defined by a first radius with respect to the central axis, the second thermal conductive element is defined by a second radius with respect to the central axis, and the thermal insulation assembly is defined by a third radius with respect to the central axis, and wherein the second radius is larger than the third radius that is larger than the first radius.
In one preferred embodiment, the thermal insulation assembly is a ring extending between the top and the bottom of the plate.
In one preferred embodiment, the plate has at least one groove extending from the bottom toward the top, the ring is inserted into the at least one groove.
Another objective of the present invention is to provide a reaction chamber including the wafer pedestal as mentioned above.
The foregoing and other features and advantages of the present disclosure will be described in detail in the following detailed descriptions of several embodiments as well as in the accompanying drawings illustrating the principles of the invention.
Aspects of the disclosure can be better understood with reference to the following drawings. Non-limiting and non-exhaustive embodiments are described with reference to the following drawings. The components in the drawings are not necessarily to scale, with the emphasis instead being placed upon illustrating the structure and principles of the invention.
The present disclosure will be fully described with reference to the drawings showing illustrated embodiments of the invention. However, given that this claimed subject matter can be achieved through various forms, the construction of the subject matter being covered or filed is not limited to any illustrated embodiments disclosed herein, which are merely illustrative. Similarly, the present disclosure aims to provide a reasonably wide scope to the claimed subject matter being filed or covered. Furthermore, illustrated embodiments of the claimed subject matter can be, for example, a method, a device or a system. Therefore, these embodiments may be implemented in hardware, software, firmware or any form of combination thereof (which is, as it is known, not software).
Appearances of the phrase “in one embodiment” herein are not necessarily referring to the same embodiment, and appearances of the phrase “in other embodiments” herein are not necessarily referring to a different embodiment. This for the purpose of, for example, stating that the claimed subject matter includes combinations of all or part of the illustrated embodiments.
Despite the absence of a top view in the drawings, the lateral carrying surface of the plate (202) generally is a circular surface. The shape of the top (2021) and/or the bottom (2022) is defined by a central axis (C) and a radius (R) extending radially about the central axis (C). The central axis (C) and the post (204) are substantially parallel, and the central axis (C) is perpendicular to the lateral carrying surface of the top (2021). The radius (R) and the thickness (H) of plate (202) are well determined to define a space sufficient for embedding the heating assembly in the plate (202) as shown in
In the illustrated embodiment, the plate (202) includes plural lift pin guides (2023) extending between the top (2021) and the bottom (2022) to allow corresponding lift pins pass through from the bottom (2022) toward the top (2021) to elevate the wafer. The post (204) extends downward from the bottom (2022) of plate (202). The post (204) is a hollow structure that allow accommodation of parts of the heating assembly, such as metal rods shown in
A second thermal conductive element (306b) has a second extending member (3062b) in the vertical direction between the bottom of reaction chamber and the plate. As shown in the figure, the second extending member (3062b) is symmetrical with respect to the central axis (C) and sandwich the first extending member (3062b). The second extending member (3062b) are two parallel metal rods. A second coil member (3061b) of the second thermal conductive element (306b) extends over a lateral plane (not depicted) at the top of the second extending member (3062b) and at least in part surrounds the central axis (C) at a second radius (R2). The second coil member (3061b) is slightly elevated above the first coil member (3061a) to avoid structural interference. The second coil member (3061b) is similar with a circular coil. In other embodiments, the shape of second coil member (3061b) may be rectangular, polygon or radiation.
The first and second coil members (3061a and 3061b) further have initial extending members (3063a, 3063b) provided between the respect extending members (3062a, 3062b) and their coil circumference portions. As shown in figure, a first initial extending member (3063a) and a second initial extending member (3063b) extend in opposite direction from the respective coil portions such that the produced heat will be dispersed over two halves of the plate and avoid heat accumulation on one side. In addition to that, less or more number of thermal conductive elements may be included. For example, the heating assembly may be composed of one single thermal conductive element having plural coil members distributed at different radiuses. Given that, in some embodiments, more heating zones could be defined depending on the number and/or the layout of the coil. In the embodiment, the plate (302) has a first heating zone defined by the first coil member (3061a) and a second heating zone defined by the second coil member (3061b). Said two heating zones might overlap with each other or be separate. In another embodiment, the first coil member (3061a) is elevated slightly higher than the second coil member (3061b). In some embodiments, based on design purpose, said coil member may include portions that extend in vertical direction.
Referring back to
As shown in the figure, a portion of the thermal insulation assembly (308) according to the embodiment has one or more cutouts (3082) formed thereon that respectively corresponds to the initial extending member (3063b) of the second coil member (3061b) such that a portion of the second coil member (3061b) passes through and surrounds the insulation structure. Among the various changes, the shape and position of cutouts may be determined depending on the layout of thermal conductive elements. In the embodiment, the thermal insulation assembly (308) is positioned at a third radius (R3) with respect to the central axis (C). As can be seen in
The wafer pedestal according to the invention provides a plate with heating means. Particularly, the plate includes a heating assembly and a thermal insulation assembly embedded therein. Said thermal insulation assembly is embedded within the plate according to one or more radial positions and extends in a vertical direction in order to cover the most of a longitudinal area of the plate. Based on said radial positions and the insulation layout, the plate can be at least divided into a first heating zone and a second zone to thereby fulfill a multi-zone heating approach for wafer while the thermal gradient of the wafer can be controlled.
Although certain details have been used to describe the present disclosure for a better understanding, it will be appreciated that certain changes and modifications may be made thereto within the scope of the claims. Therefore, the foregoing embodiments are presented merely as an exemplary and are not intended to limit the present disclosure. Also, the present disclosure is not limited by the details in the description herein, but allows to be modified within the scope of the appended claims and their equivalents.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201810413913.4 | May 2018 | CN | national |
