Patent Application
20160348276
Field
Embodiments described herein generally relate to a semiconductor process chamber. More specifically, embodiments of the disclosure relate to a semiconductor process chamber having one or more reflectors.
Description of the Related Art
In the fabrication of integrated circuits, deposition processes are used to deposit films of various materials upon semiconductor substrates. These deposition processes may take place in an enclosed process chamber. Epitaxy is a deposition process that grows a thin, ultra-pure layer, usually of silicon or germanium on a surface of a substrate. Forming an epitaxial layer on a substrate with uniform thickness across the surface of the substrate can be challenging. For example, there are often portions of the epitaxial layer, where the thickness dips or rises for an unknown reason. These variations in thickness degrade the quality of the epitaxial layer and can increase production costs. Thus, there is a need for an improved process chamber to produce epitaxial layers having a uniform thickness across the surface of the substrate.
Embodiments disclosed herein generally relate to a reflector to be used in a semiconductor process chamber. In one embodiment, a reflector for processing a semiconductor substrate is provided. The reflector includes an annular body having an outer edge, an inner edge, and a bottom side. The bottom side includes a plurality of first surfaces and a plurality of second surfaces. Each first surface and each second surface is positioned at a different angular location around the annular body. Each first surface is a curved surface having a radius of curvature from about 1.50 inches to about 2.20 inches.
In another embodiment, a reflector for processing a semiconductor substrate is provided. The reflector includes an annular body having an outer edge, an inner edge, and a bottom side. The bottom side includes 20 first surfaces and 12 second surfaces. Each first surface and each second surface is positioned at a different angular location around the annular body. Each first surface is a curved surface having a radius of curvature from about 2.02 inches to about 2.10 inches. Each second surface is disposed adjacent to, and between, two first surfaces.
In another embodiment, a process chamber is provided including a sidewall, a substrate support, and a first reflector disposed above the substrate support. The first reflector includes an annular body having an outer edge, an inner edge, and a bottom side, the bottom side including a plurality of first surfaces and a plurality of second surfaces. Each first surface and each second surface is positioned at a different angular location around the annular body. Each first surface is a curved surface having a radius of curvature from about 1.50 inches and about 2.20 inches.
So that the manner in which the above recited features of the disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this disclosure and are therefore not to be considered limiting of its scope, for the disclosure may admit to other equally effective embodiments.
To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one embodiment may be beneficially utilized on other embodiments without specific recitation.
Embodiments described herein generally relate to a semiconductor process chamber. More specifically, embodiments of the disclosure relate to a semiconductor process chamber having one or more reflectors.
In this disclosure, the terms “top”, “bottom”, “side”, “above”, “below”, “up”, “down”, “upward”, “downward”, “horizontal”, “vertical”, and the like do not refer to absolute directions. Instead, these terms refer to directions relative to a basis plane of the chamber, for example a plane parallel to a substrate processing surface of the chamber.
The process chamber 100 further includes a substrate support 110 disposed in the chamber body 101 to support the substrate 50 during processing. The substrate 50 on the substrate support 110 can be heated by lamps 150 disposed above and below the substrate support 110. The lamps 150 can be, for example, tungsten filament lamps. The lamps 150 below the substrate support 110 can direct radiation, such as infrared radiation, through a lower dome 120 disposed below the substrate support 110 to heat the substrate 50 and/or the substrate support 110. The lower dome 120 can be made of a transparent material, such as quartz. In some embodiments, a substrate support 110 having a ringed shape may be used. A ringed-shaped substrate support can be used to support the substrate 50 around the edges of the substrate 50, so that the bottom of the substrate 50 is directly exposed to the heat from the lamps 150. In other embodiments, the substrate support 110 is a heated susceptor to increase temperature uniformity of the substrate 50 during processing. The lamps 150 below the substrate support 110 can be installed within or adjacent to a lower outer reflector 130 and within or adjacent to a lower inner reflector 132. The lower outer reflector 130 can surround the lower inner reflector 132. The lower outer reflector 130 and the lower inner reflector 132 can be formed of aluminum and plated with a reflective material, such as gold. A lower temperature sensor 191, such as a pyrometer, can be installed in the lower inner reflector 132 to detect a temperature of the substrate support 110 or the back side of the substrate 50.
The lamps 150 above the substrate support 110 can direct radiation, such as infrared radiation, through an upper dome 122 disposed above the substrate support 110. The upper dome 122 can be made of a transparent material, such as quartz. The lamps 150 above the substrate support 110 can be installed within or adjacent to an upper inner reflector 200 (a first reflector) and within or adjacent to an upper outer reflector 140 (a second reflector). The upper outer reflector 140 can surround the upper inner reflector 200. The upper outer reflector 140 and the upper inner reflector 200 can be formed of aluminum and plated with a reflective material, such as gold. An upper temperature sensor 192, such as a pyrometer, can be installed in or adjacent to the upper inner reflector 200 to detect a temperature of the substrate 50 during processing. Although
The process chamber 100 can be coupled to one or more process gas sources 170 that can supply the process gases used in the epitaxial depositions. The process chamber 100 can further be coupled to an exhaust device 180, such as a vacuum pump. In some embodiments, the process gases can be supplied on one side (e.g., the left side of
The partial side sectional view of
The plurality of first reflecting surfaces 210 and the plurality of second reflecting surfaces 220 can be disposed around the annular body 201 in a circular array. One of the first reflecting surfaces 210 is disposed one position before and one position after each second reflecting surface 220 in the circular array. The circular array can include one or more instances in which two or more first reflecting surfaces are arranged in a row. For example, the circular array of the upper inner reflector 200 includes eight instances of two first reflecting surfaces 210 in a row. Furthermore, the circular array includes four instances in which one of the second reflecting surfaces 220 is disposed one position before and one position after one of the first reflecting surfaces 210.
Each first reflecting surface 210 is a curved surface having a radius of curvature 212 from about 1.50 inches to about 2.20 inches, such as from about 2.02 inches to about 2.10 inches, such as about 2.06 inches. On the other hand, each second reflecting surface 220 is substantially flat. In some embodiments, each first reflecting surface 210 has a cylindrical shape extending in a direction from the outer edge 202 towards the inner edge 203 of the reflector 200. In other embodiments, each first reflecting surface has a frustoconical shape extending in a direction from the outer edge 202 towards the inner edge 203 of the reflector 200. In embodiments using a frustoconical shape, the radius of curvature can decrease in the direction from the outer edge 202 towards the inner edge 203 of the reflector.
The inventors of the present application observed nonuniformities in the thickness of epitaxial layers formed on 300 mm substrates in a process chamber including the components shown in
After discovering that the thickness nonuniformities could be removed by changing the radius defining the first reflecting surfaces, the inventors then determined that a radius defining the curved surface of the first reflecting surfaces from about 1.50 inches to about 2.20 inches, such as a radius from about 2.02 inches to about 2.10 inches, such as a radius of about 2.06 inches provided the best results for removing the nonuniformities in the thickness in the epitaxial layers formed in the chambers used to process 300 mm substrates. Removing these thickness nonuniformities can improve product quality and reduce waste.
While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.
This application claims priority to U.S. Provisional Patent Application Ser. No. 62/168,670, filed on May 29, 2015, which herein is incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| 62168670 | May 2015 | US |
