Patent Application
20240134151
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 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 requires precise temperature control. Process temperature is controlled through the use of radiant heat lamps. Each lamp is typically associated with one or more reflectors that increases and directs the light energy to the substrate. The lamps and reflectors are often replaced, and thus, are a significant contributor to the operating cost of the processing chamber. The reflectors are also difficult to manufacture.
Thus, there is a need for an improved reflector for a process chamber that utilizes lamps for heating.
A reflector and processing chamber having the same are described herein. In one example, a reflector is provided that includes cylindrical body, a cooling channel, and a reflective coating. The cylindrical body has an upper surface and a lower surface. The lower surface has a plurality of concave reflector structures disposed around a centerline of the cylindrical body. The cooling channel disposed in or on the cylindrical body. The reflective coating is disposed on the plurality of concave reflector structures.
In another example, a processing chamber applicable for use in semiconductor manufacturing includes a chamber body, a plurality of lamps, a substrate support, a support surface, a window, a reflector including a cylindrical body, a plurality of concave reflector structures, a cooling channel, and a reflective coating. The chamber body having an internal volume. The substrate support disposed in the internal volume. The window disposed over the substrate support and at least partially bounding the internal volume. The reflector positioned to reflect light emitted from the lamps through the window and into the internal volume. The cylindrical body having an upper surface and a lower surface. The lower surface having a plurality of concave reflector structures disposed around a centerline of the cylindrical body. The cooling channel disposed in or on the cylindrical body. The reflective coating disposed on the plurality of concave reflector structures.
In another example, a processing chamber applicable for use in semiconductor manufacturing includes a chamber body, a plurality of lamps, a substrate support, a window, a reflector including cylindrical body, an upper surface and a lower surface, a plurality of concave reflector structures, a shell, a baffle, a cooling channel, a second cooling channel, a side surface, a reflective coating. The chamber body having an internal volume. The substrate support disposed in the internal volume. The substrate support includes a support surface. The window is disposed over the substrate support and at least partially bounding the internal volume. The reflector is positioned to reflect light emitted from the lamps through the window and into the internal volume. The cylindrical body having an upper surface and a lower surface. The lower surface having a plurality of concave reflector structures disposed around a centerline of the cylindrical body. The cylindrical body is made from a polymer. The shell extends through the cylindrical body and projects below the lower surface to a distal end. The shell is made from a second polymer where the first and second polymer is combined with a filler that improves thermal conductivity of the polymer. The filler includes one or more of boron nitride, aluminum nitride, silicon carbide, carbon-based structures, diamond, or metal powder. The baffle is coupled to the distal end of the shell. The cooling channel is disposed in or on the cylindrical body having an inlet and an outlet port disposed through the upper surface or a side surface of the cylindrical body and shell. The second cooling channel disposed in or on the shell having an inlet and an outlet port disposed through the upper surface or a side surface of the cylindrical body and shell. The reflective coating disposed on the plurality of concave reflector structures. The reflective coating is gold or aluminum.
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.
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 non-specific plane of reference. This non-specific plane of reference may be vertical, horizontal or other angular orientation.
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 reflector for use in a semiconductor process chamber, and a semiconductor process chamber having the same. The reflector is generally fabricated from a polymer and has a reflective coating disposed on a plurality of concave surfaces formed in one side of the reflector.
Conventional light reflectors disposed on a processing chamber are generally fabricated from a metal, such as aluminum. These aluminum reflectors are coated with a reflective coating that directs infrared light emitted by a lamp to a substrate disposed within the process chamber. However, machining these aluminum reflectors is time intensive, costly, may delay operations should a replacement be required. The disclosure below is a nonmetallic reflector body, coated with a reflective material which provides a significant improvement over the aluminum reflectors. The nonmetallic based reflector provides flexibility in construction, including, reflectivity layer selecting, and nonmetal material selection which may lead to faster reproduction of spare parts and less processing chamber downtime. Moreover, the nonmetallic based reflector can include integrated cooling for improved performance and longer service life. The nonmetallic based reflector can also include integrated light baffles that reduce the number of components needed to operate the chamber, and also simplifies the supply chain and amount of components needed to be inventoried to adequately service the processing chamber.
Turning now to the side sectional view of a process chamber 100 illustrated in
The process chamber 100 further includes a substrate support 110 disposed in the internal volume 125 of the chamber body 101 to support the substrate 160 during processing. The substrate 160 disposed on the substrate support 110 is heated by lamps 150. The lamps 150 are disposed above and/or below the substrate support 110. The lamps 150 can be, for example, tungsten filament lamps or high power LEDs. The lamps 150 below the substrate support 110 can direct radiation, such as infrared radiation, through the lower dome 120 disposed below the substrate support 110 to heat the substrate 160 and/or the substrate support 110. The lower dome 120 is made of a transparent material, such as quartz. In some embodiments, a substrate support 110 having a ring shape may be used. A ring-shaped substrate support can be used to support the substrate 160 around the edges of the substrate 160, so that the bottom of the substrate 160 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 160 during processing. The lamps 150 below the substrate support 110 can be installed within or adjacent to a lower reflector 130 and within or adjacent to a lower shell assembly 132. The lower reflector 130 can surround the lower shell assembly 132. Generally, the lower reflector 130 and the lower shell assembly 132 can be formed of a polymer, coated with a reflective material, such as, for example, gold, aluminum or other suitable material. A lower temperature sensor 191, such as a pyrometer, can be installed in the lower shell assembly 132 to detect a temperature of the substrate support 110 or the back side of the substrate 160. Alternatively, one or both of the lower reflector 130 and the lower shell assembly 132 may be fabricated as later described below with reference to an upper shell assembly 190 and an upper reflector 140.
The lamps 150 above the substrate support 110 can direct radiation, such as infrared radiation, through the upper dome 122 disposed above the substrate support 110. The upper dome 122 is made of a transparent material, such as quartz. The lamps 150 above the substrate support 110 can be installed adjacent to the upper shell assembly 190 and within or adjacent to an upper reflector 140. The upper reflector 140 can surround the perimeter of the upper shell assembly 190. Generally, the upper reflector 140 and the upper shell assembly 190 can be formed of polymer coated with a reflective material, such as, for example, gold, aluminum or other suitable material. An upper temperature sensor 192, such as a pyrometer, can be installed in or adjacent to the upper shell assembly 190 to detect a temperature of the substrate 160 during processing. Although
The upper reflector 140, the lower reflector 130, the upper shell assembly 190, and the lower shell assembly 132 can be manufactured by processes such as, but not limited to, casting, injection molding, compression molding (e.g., pressed powder), and 3D printing (additive manufacturing). One, some or all of the upper reflector 140, the lower reflector 130, the upper shell assembly 190, and the lower shell assembly 132 have a reflective coating suitable for directing light toward the substrate 160 or away from a location where light is undesired. The reflective coating may be, but is not limited to, reflective materials such as, gold and aluminum, among others. The reflective coating may include a transparent protective layer, such as a protective magnesium fluoride layer, disposed over the reflective materials. The reflective coating may optionally include an underlying adhesion layer, such as nickel. In one example, the reflective coating is a gold layer having a thickness of about 50 nm to about 300 nm and high reflectivity for infra-red wavelength (about 700 nm to 1 mm). A gold reflective coating may have a reflectance of 90% or more. In another example, the reflective coating is an aluminum layer having a thickness of about 50 nm to about 300 nm. When present, the magnesium fluoride layer protection layer may be about 20 nm to about 1 μm thick. The resulting reflective coating may have a reflectance of 90% or more. In all embodiments, the thickness of the coatings is selected such that the reflectance of the cylindrical body is 90% or more.
The upper reflector 140, the lower reflector 130, the upper shell assembly 190, and the lower shell assembly 132 can be manufactured by polymer materials such as, but not limited to, polyether ether ketone (PEEK), polyimide, or other suitable high temperature polymers. All, some or none of the upper reflector 140, the lower reflector 130, the upper shell assembly 190, and the lower shell assembly 132 may be manufactured from the same material, as similarly, all, some or none of the upper reflector 140, the lower reflector 130, the upper shell assembly 190, and the lower shell assembly 132 may be have the same coating.
The process chamber 100 is coupled to one or more process gas sources 170 that supply the process gases used in the epitaxial depositions. The process chamber 100 is further 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 concave reflector structures (e.g., the first reflecting surfaces 21) are disposed around the annular body 201 in a circular array relative to a centerline of the cylindrical body. At least one of the first reflecting surfaces 210 is disposed between 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 consecutively. For example, the circular array of the upper reflector 140 includes eight instances of two first reflecting surfaces 210 spaced consecutively. 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 has 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. On the other hand, each second reflecting surface 220 is substantially flat. In some embodiments, each first reflecting surface 210 has a partial cylindrical shape extending in a radial direction from the outer edge 202 towards the inner edge 203 of the upper reflector 140. 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 upper reflector 140. In embodiments having a frustoconical shape, the radius of curvature decreases in the radial direction from the outer edge 202 to the inner edge 203 of the reflector 140.
The baffle structure 350 includes a middle baffle 352, a top baffle 354, and a cylindrical sensor tube 356. The middle baffle 352 and the top baffle 354 have a disk shape and are disposed around a common centerline of the cylindrical sensor tube 356. The baffle structure 350 may be constructed of the same material as the upper reflector 140, or other suitable material, such as aluminum.
The lower baffle 311 may be connected to the inner diameter surface 302 of the shell body 301. The top surface 325 of the lower baffle 311 may be connected to the inner diameter surface 302 by connectors 313 in a manner that creates an annular gap 312 between the inner diameter surface 302 and the outer edge 328. The connector 313 may be a bracket or structure suitable for connecting the lower baffle 311 to the shell body 301. In another embodiment, the connectors 313 are a web of material extending between the outer edge 328 of the lower baffle 311 and the inner diameter surface 302 at the distal end 303 of the shell body 301 when the shell body 301 and lower baffle 311 are fabricated as a monolithic structure. Furthermore, it is contemplated the upper shell assembly 190, including the optional lower baffle 311 and baffle structure 350, are formed as a monolithic structure. The lower baffle 311 is constructed of the same material as the upper reflector 140 and coated similarly. Furthermore, the lower baffle 311 may have a cut out 314 that enables a second temperature sensor, for example a pyrometer not shown, to have a line of sight down to the edge of the substrate 160. The cylindrical sensor tube 356 is generally utilized to provide a line of sight for a first temperature sensor, for example the upper temperature sensor 192 shown in
The shell assembly 190, including the lower baffle 311, may be constructed of the same material as the upper reflector 140 and coated similarly. The shell assembly 190 is configured to be inserted adjacent to the inner edge 203 of the upper reflector 140. The outer diameter of shell flange 305 is greater than the inner diameter of the inner edge 203 of the upper reflector 140 causing a lower surface 307 of the shell flange 305 to make at least partial contact with the top side 214 of the upper reflector 140 when inserted within the cylindrical body of the upper reflector 140.
As previously mentioned, nonmetals may be used to manufacture the reflector assembly 300. The nonmetallic or polymer body with reflective coating may be used on other components disposed on or within the chamber body that receive light or heat from lamp 150. These nonmetal or polymer bodies are exposed to high temperature during operation of the process chamber 100 of
Similarly, the shell assembly 490 comprises a shell flange and a shell body 401 that contains a formed cavity 445 between the shell body 401 inner wall 402, an outer wall 404, a distal end 403, and a proximate end 416. A cavity 445 is formed between the inner and outer wall where a cooling medium may be provided to thermally regulate the shell body 401 and prevent overheating. The cavity 445 has a shell inlet port 441 and a shell outlet port 442. The ports 441, 442 allow the flow to ingress and egress of the cooling medium from the cavity 445.
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.
