Active temperature control of showerheads for high temperature processes

Abstract

A showerhead for a substrate processing system includes a backplate constructed from a metallic material and a faceplate constructed from a ceramic material, the showerhead further includes a first cooling plate disposed between the backplate and a central region of the faceplate, and a plurality of heaters disposed between the backplate and a peripheral region of the faceplate.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 302,279, filed January 24, 2022. The disclosure of the above application is incorporated herein by reference in its entirety. [Technical field]

[0002] The present disclosure relates generally to semiconductor processing systems, and more particularly to a corrosion resistant heater for active temperature control of a showerhead for high temperature processes. [Background technology]

[0003] The background description provided herein is intended to provide a general overview of the contents of the present disclosure. Work by the currently named inventors within the scope of what is described in this background section, as well as aspects of the description that may not otherwise be considered prior art at the time of filing, are not admitted, expressly or impliedly, as prior art against the present disclosure.

[0004] Atomic layer deposition (ALD) is a thin film deposition technique in which gas chemical processes are performed sequentially to deposit thin films on the surface of a material (e.g., the surface of a substrate such as a semiconductor wafer). Most ALD reactions use at least two chemicals, called precursors (reactants), to react sequentially with the surface of the material, one precursor at a time, in a self-limiting manner. By repeated exposure to separate precursors, thin films are gradually deposited on the surface of the material.

[0005] Thermal ALD (T-ALD) is carried out in a heated processing chamber. The processing chamber is maintained at sub-atmospheric pressure using a vacuum pump and a controlled flow of inert gas. The substrate to be coated with the ALD film is placed in the processing chamber and allowed to equilibrate to the temperature of the processing chamber before starting the ALD process. Summary of the Invention

[0006] A showerhead for a substrate processing system includes a backplate constructed from a metallic material and a faceplate constructed from a ceramic material, the showerhead further includes a first cooling plate disposed between the backplate and a central region of the faceplate, and a plurality of heaters disposed between the backplate and a peripheral region of the faceplate.

[0007] In further features, the first cooling plate and the plurality of heaters are in direct thermal contact with the faceplate.

[0008] In a further feature, the first cooling plate is in direct thermal contact with the backplate.

[0009] In a further feature, the first cooling plate includes a material having a higher thermal conductivity than a metallic material of the backplate.

[0010] In a further feature, the backplate is made of aluminum or an alloy and the first cooling plate is made of copper.

[0011] In further features, the first cooling plate and the multiple heaters lie in a plane parallel to the faceplate.

[0012] In a further feature, the plurality of heaters surround the first cooling plate.

[0013] In a further feature, each heater of the plurality of heaters is controlled independently from the remaining heaters of the plurality of heaters.

[0014] In a further feature, a portion of each of the plurality of heaters is in direct contact with the faceplate, and a remaining portion of each of the plurality of heaters is encapsulated in an electrically insulating and thermally conductive material.

[0015] In a further feature, the showerhead further includes a layer of thermally resistant material disposed between the plurality of heaters and the backplate, the thermally resistant material having a lower thermal conductivity than the backplate.

[0016] In a further feature, the layer is annular with an inner diameter greater than a diameter of the first cooling plate and an outer diameter equal to or less than a diameter of the faceplate.

[0017] In a further feature, a diameter of the first cooling plate is greater than or equal to half the diameter of the faceplate.

[0018] In a further feature, the multiple heaters are arranged along a circle having a diameter less than or equal to a diameter of the faceplate.

[0019] In a further feature, the first cooling plate comprises a heater.

[0020] In a further feature, the heater is a low power heater as compared to the plurality of heaters.

[0021] In a further feature, the heater is in direct thermal contact with at least one of the backplate and the faceplate.

[0022] In a further feature, the showerhead further comprises a second cooling plate disposed on the backplate, the second cooling plate comprising cooling channels for circulating a coolant therethrough.

[0023] In a further feature, the showerhead further includes a layer of thermally resistant material disposed between the backplate and the second cooling plate, the thermally resistant material having a lower thermal conductivity than the backplate.

[0024] In a further feature, the showerhead further includes a plurality of layers of thermally resistant material disposed between the backplate and the second cooling plate, the thermally resistant material having a lower thermal conductivity than the backplate, the thermal conductivity of the layers increasing from the backplate to the second cooling plate.

[0025] In a further feature, at least one of the plurality of layers includes a pattern of features that provide air pockets.

[0026] In a further feature, the showerhead further comprises a stem comprising a metallic portion and a ceramic portion, the ceramic portion being embedded within the metallic portion and the backplate.

[0027] In a further feature, the ceramic portion includes a plurality of segments extending radially from the ceramic portion, the distal ends of the segments extending perpendicular to the segments to the faceplate.

[0028] In a further feature, the distal end extends through a notch in the first cooling plate to the faceplate.

[0029] In a further feature, the stem comprises a gas inlet. The metallic portion, the ceramic portion, and the plurality of segments comprise gas passages in fluid communication with the gas inlet.

[0030] In a further feature, the faceplate includes a plurality of through holes. The gas passage is in fluid communication with the through holes.

[0031] Further areas of applicability of the present disclosure will become apparent from the detailed description, the claims, and the drawings. The detailed description and specific examples are for purposes of illustration only and are not intended to limit the scope of the present disclosure. [Brief description of the drawings]

[0032] The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein:

[0033] [Figure 1] FIG. 1 illustrates an example of a substrate processing system including a processing chamber.

[0034] [Diagram 2] FIG. 2 illustrates an example of a showerhead for use in the processing chamber of FIG.

[0035] [Diagram 3] FIG. 3 shows an example of a first cooling plate with a heater disposed above a central region of the faceplate of the showerhead of FIG.

[0036] [Figure 4] FIG. 4 shows an example of a first cooling plate and outer heater disposed above the peripheral region of the showerhead of FIG.

[0037] [Diagram 5] FIG. 5 illustrates an example of a gas distribution manifold for the showerhead of FIG. [Figure 6] FIG. 6 illustrates an example of a gas distribution manifold for the showerhead of FIG.

[0038] [Figure 7] FIG. 7 shows an example of a thermal resistor disposed between the backplate of the showerhead of FIG. 2 and a second cooling plate disposed above the backplate.

[0039] In the drawings, reference numbers may be reused to identify similar and / or identical elements. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0040] In some processes, the pedestal used to support the substrate has a ceramic top plate and the showerhead used to deliver process gases has a ceramic face plate. In these processes, the gap between the pedestal top plate and the showerhead face plate is narrow. The processes require the showerhead and the pedestal to be heated to high temperatures. In addition, the pedestal is heated to a temperature higher than the temperature of the showerhead. Because of the narrow gap between the pedestal and the showerhead, heat from the pedestal is coupled into the showerhead face plate.

[0041] Some processes use process gases with high thermal conductivity, and these processes have long soak times (i.e., the time the faceplate is exposed to these gases). In these processes, the faceplate tends to heat up more in the center region than in the peripheral region, resulting in darkening of the center region. This darkening causes the center region to tend to be hotter than the peripheral region, resulting in large temperature gradients across the radius of the faceplate, which can cause damage (e.g., cracking) to the faceplate.

[0042] The present disclosure solves these and other problems by providing a cooling plate over a central region of a faceplate and a plurality of heaters over a peripheral region of the faceplate. The cooling plate and heaters are disposed between a faceplate and a metallic backplate of the showerhead. The cooling plate and heaters are in thermal contact with the faceplate and the backplate. The backplate is cooled using cooling channels disposed above the backplate. The cooling plate conducts heat from the central region of the faceplate. The heat conducted by the cooling plate is transferred to the backplate, which is cooled by the cooling channels.

[0043] A heater located above the peripheral region of the faceplate (also called an outer heater) heats the peripheral region of the faceplate. A cooling plate above the central region of the faceplate also includes a heater. The cooling plate heater can heat the central region as well as cool it. By controlling the heat provided by the cooling plate and the heat provided by the outer heater, a uniform temperature gradient can be achieved across the radius of the faceplate.

[0044] In some examples, a layer of thermally resistant material may be disposed between the outer heater and the backplate. In some examples, one or more layers of thermally resistant material may also be disposed between the backplate and the cooling channels. These layers may be patterned, as described in more detail below.

[0045] Additionally, the present disclosure provides gas distribution channels from the stem of the showerhead to the faceplate to deliver process gases to the faceplate. The gas distribution channels are designed to separate the process gases flowing through the showerhead and the process by-products escaping through the showerhead from fluid communication with the cooling plate and heater. This separation allows for optimization of heater materials and heating element designs without limiting compatibility with corrosive by-products of the process chemistry.

[0046] Further, the stem, which is connected to the backplate, receives the heat conducted by the backplate. The stem is typically made of metal coated with a rust-preventive material. To prevent the stem from being damaged by heat from the backplate, the stem according to the present disclosure includes an upper metal portion and a lower ceramic portion embedded in the upper metal portion. The metal portion is lined with a rust-preventive material to prevent corrosion by process gases flowing through the stem. The ceramic portion is connected to the backplate. The ceramic portion is not only not corroded by the process gases, but can also withstand heat from the backplate. Further, a gas distribution channel extends from the ceramic portion to the faceplate, the gas distribution channel also being composed of a ceramic material. The gas distribution channel passes through cavities in the backplate and the cooling plate. These and other features of the present disclosure are described in detail below.

[0047] The present disclosure is organized as follows: With reference to FIG. 1, an example of a processing chamber in which a showerhead according to the present disclosure can be used is shown and described; With reference to FIG. 2, a showerhead according to the present disclosure is shown and described; With reference to FIG. 3, an example of a cooling plate with a heater disposed above a central region of the faceplate of the showerhead is shown and described; With reference to FIG. 4, an outer heater and cooling plate disposed above a peripheral region of the faceplate is shown and described in further detail; With reference to FIG. 5 and FIG. 6, a ceramic gas distribution manifold embedded in the showerhead stem and backplate is shown and described in further detail; With reference to FIG. 7, a thermal resistor used between the showerhead backplate and the upper cooling plate is shown and described in further detail. Example of a substrate processing system

[0048] 1 illustrates an example of a substrate processing system 100 that includes a processing chamber 102 configured to process a substrate using thermal atomic layer deposition (T-ALD). The processing chamber 102 surrounds the other components of the substrate processing system 100. The processing chamber 102 includes a substrate support (e.g., pedestal) 104. During processing, a substrate 106 is disposed on the pedestal 104.

[0049] One or more heaters 108 (e.g., a heater array) may be disposed on a ceramic plate that is disposed on a metallic base plate of the pedestal 104 to heat the substrate 106 during processing. One or more additional heaters, referred to as zone heaters or primary heaters (not shown), may be disposed on the ceramic plate above or below the heater 108. Additionally, although not shown, a cooling system may be disposed in the base plate of the pedestal 104 including cooling channels through which a coolant flows to cool the pedestal 104, and one or more temperature sensors may be disposed in the pedestal 104 to sense the temperature of the pedestal 104.

[0050] The processing chamber 102 includes a gas distribution apparatus 110, such as a showerhead, for introducing and distributing process gases into the processing chamber 102. The gas distribution apparatus (hereafter showerhead) 110 includes a stem 112. One end of the stem 112 is connected to an upper surface of the processing chamber 102. A backplate 114 of the showerhead 110 is generally cylindrical and extends radially outward from the opposite end of the stem 112 at a location spaced apart from the upper surface of the processing chamber 102. The surface of the backplate 114 of the showerhead 110 that faces the substrate includes a faceplate (shown in subsequent figures). The faceplate includes a number of outlets or features (e.g., slots or through-holes) through which process gases enter the processing chamber 102.

[0051] The showerhead 110 also includes multiple cooling plates and multiple heaters (shown and described with reference to subsequent figures). The upper cooling plate includes conduits (see FIG. 2) through which a coolant may be circulated. Additionally, although not shown, one or more temperature sensors may be disposed within the showerhead 110 to sense the temperature of the showerhead 110. The showerhead 110 includes additional features, such as one or more thermal resistors, shown and described in more detail below with reference to subsequent figures.

[0052] The gas delivery system 130 includes one or more gas sources 132-1, 132-2, ..., and 132-N (collectively, gas sources 132), where N is an integer greater than zero. The gas sources 132 are connected to a manifold 139 by valves 134-1, 134-2, ..., and 134-N (collectively, valves 134) and mass flow controllers 136-1, 136-2, ..., and 136-N (collectively, mass flow controllers 136). An output of the manifold 139 is provided to the processing chamber 102. The gas sources 132 may provide process gases, cleaning gases, purge gases, inert gases, etc. to the processing chamber 102.

[0053] The fluid supply system 140 supplies coolant to the cooling system in the pedestal 104 and to the upper cooling plate in the showerhead 110. A temperature controller 150 may be connected to the heater 108, the zone heaters, the cooling system, and temperature sensors in the pedestal 104. The temperature controller 150 may also be connected to the cooling plate, the heater, and temperature sensors in the showerhead 110. The temperature controller 150 may control the power supplied to the heater 108, the zone heaters, and the flow of coolant through the cooling system in the pedestal 104 to control the temperature of the pedestal 104 and the substrate 106. The temperature controller 150 may also control the power supplied to the heaters located in the showerhead 110 and the flow of coolant through conduits located in the upper cooling plate of the showerhead 110 to control the temperature of the showerhead 110.

[0054] A vacuum pump 158 maintains a sub-atmospheric pressure inside the processing chamber 102 during substrate processing. A valve 156 is connected to an exhaust port of the processing chamber 102. The valve 156 and vacuum pump 158 are used to control the pressure within the processing chamber 102 and to evacuate reactants from the processing chamber 102 via the valve 156. A system controller 160 controls the components of the substrate processing system 100. Shower head example

[0055] Figure 2 shows a cross-sectional view of a showerhead 200 according to the present disclosure. The showerhead 200 can be used in place of the showerhead 110 in the processing chamber 102 shown in Figure 1. The showerhead 200 includes a faceplate 202, a backplate 204, and a stem 206, each of which is cylindrical.

[0056] The faceplate 202 is constructed from a ceramic material. The faceplate 202 includes a plenum 210 defined by a sidewall 203 of the faceplate 202 and upper and lower surfaces 205, 207 of the faceplate 202. The lower surface 207 of the faceplate 202 includes a plurality of through holes 212-1, 212-2, ..., and 212-N (collectively, through holes 212), where N is a positive integer. The through holes 212 extend from the lower surface 207 of the faceplate 202 to the plenum 210. The through holes 212 are in fluid communication with the plenum 210.

[0057] The backplate 204 has a larger diameter than the faceplate 202. The backplate 204 is made of a metal, such as aluminum or an alloy. An upper surface 205 of the faceplate 202 is attached to a lower surface 211 of the backplate 204. A stem 206 is attached to an upper central region of the backplate 204. The stem 206 includes an inlet 208 for receiving process gas.

[0058] The stem 206 is comprised of a metal portion 220 and a ceramic portion 222 that is embedded within a lower central region 230 of the metal portion 220. The ceramic portion 222 includes an upper portion 232 and a lower portion 234. The upper portion 232 of the ceramic portion 222 is embedded within the lower central region 230 of the metal portion 220. The lower portion 234 of the ceramic portion 222 is embedded within the upper central region of the backplate 204.

[0059] The ceramic portion 222 includes a number of segments (elements 242 shown in FIGS. 5 and 6) that extend radially from the lower portion 234 of the ceramic portion 222 through respective slots in the backplate 204. The distal ends (referred to as ports), only two of which are shown at 240-1, 240-2 (collectively ports 240), extend perpendicular to the segments 242 towards the faceplate 202. The ports 240 are disposed within respective slots in the backplate 204. The ports 240 are attached to the upper surface 205 of the faceplate 202 as will be shown in further detail with reference to FIGS. 5 and 6 and described below.

[0060] A plurality of gas passages pass through the metal portion 220 and ceramic portion 222 of the stem 206, through the segments 242 and ports 240, and through the faceplate 202. The gas passages are shown at 250-1, 250-2, 250-3, 250-4, 250-5, 250-6, and 250-7 (collectively, gas passages 250). The gas passages 250 are in fluid communication with the inlet 208 of the stem 206 and are in fluid communication with the plenum 210 and the through holes 212 in the faceplate 202. The ceramic portion 222 and the gas passages 250 in the ceramic portion 222 define a gas distribution manifold in the backplate 204. The gas distribution manifold (elements 222 and 250) delivers process gases from the inlet 208 of the stem 206 to the faceplate 202.

[0061] A first cooling plate 260 is disposed above a central region of the upper surface 205 of the faceplate 202. The first cooling plate 260 is circular, as shown in more detail with reference to Figure 3 and described below. In some examples, the first cooling plate 260 has a diameter that is half or more than the diameter of the faceplate 202.

[0062] The first cooling plate 260 is made of a metal (e.g., copper) having a high thermal conductivity. For example, the first cooling plate 260 is constructed of a material having a higher thermal conductivity than the backplate 204. The first cooling plate 260 is in direct thermal contact with the backplate 204 and in direct thermal contact with the top surface 205 of the faceplate 202. The first cooling plate 260 conducts heat from a central region of the faceplate 202 and transfers the conducted heat to the backplate 204.

[0063] 3 and described below. In some processes, the heater 262 can be used to heat a central region of the faceplate 202. The heater 262 and first cooling plate 260 extend radially beyond the port 240 in the ceramic portion 222 of the stem 206 toward the outer diameter (OD) of the faceplate 202.

[0064] A number of heaters (referred to as outer heaters), only two of which are shown at 270-1 and 270-2 (collectively, outer heaters 270), are disposed above the upper surface 205 of the faceplate 202. The outer heaters 270 are disposed along the periphery of the faceplate 202 (e.g., proximate the OD). The outer heaters 270 are shown in further detail with reference to FIG. 4 and described below. Briefly, the outer heaters 270 are disposed within respective slots in the backplate 204. The outer heaters 270 are encapsulated in an electrically insulating material 272 (e.g., aluminum nitride) having high thermal conductivity. The outer heaters 270 heat the peripheral region of the faceplate 202.

[0065] The bottom surface of the outer heater 270 may be in direct thermal contact with the top surface 205 of the faceplate 202. The top surface of the insulating material 272 may be in direct thermal contact with the backplate 204. In some examples, a first thermal resistor 274 may be disposed between the top surface of the insulating material 272 and the backplate 204. The first thermal resistor 274 is shown in further detail with reference to FIG. 4 and described below. The first thermal resistor 274 can reduce heat transfer from the outer heater 270 to the backplate 204.

[0066] A controller (e.g., controller 160 shown in FIG. 1 ) controls the power supplied to the outer heater 270 and the heater 262 in the first cooling plate 260. The outer heater 270 is a high-power heater compared to the heater 262. The outer heater 270 can provide more heat than the heater 262. The controller can individually control the outer heaters 270 independent of each other. For example, the controller can not only turn each of the outer heaters 270 on and off, but also control the amount of power supplied to each of the outer heaters 270, which determines the amount of heat generated by each of the outer heaters 270. The heat supplied to the faceplate 202 by the heaters 270, 262 and the heat conducted from the faceplate 202 by the first cooling plate 260 provides temperature uniformity across the radius of the faceplate 202. Additionally, in some processes, the heaters 270 , 262 can be controlled to provide a desired temperature gradient or zone across the radius of the faceplate 202 .

[0067] A second cooling plate 280 is disposed above the backplate 204. The second cooling plate 280 is annular and its OD is equal to or less than the OD of the faceplate 202. The second cooling plate 280 includes a conduit 282 through which coolant from a fluid supply system flows. The second cooling plate 280 may include multiple conduits through which coolant can flow at different flow rates. The second cooling plate 280 cools the backplate 204. Heat conducted by the first cooling plate 260 from the central region of the faceplate 202 and transferred to the backplate 204 is removed from the backplate 204 by the second cooling plate 280. A portion of the heat generated by the outer heater 270 that is transferred to the backplate 204 is also removed from the backplate 204 by the second cooling plate 280.

[0068] The coolant flowing through the conduits 282 may become hot and lose its ability to provide cooling (i.e., cooling capacity) as heat flows from the faceplate 202 to the second cooling plate 280. For example, if water is used as the coolant (although other coolants can be used), the water may boil at 100 degrees and lose its cooling capacity. Because the temperature of the showerhead 200 can reach hundreds of degrees, it is necessary to keep the temperature of the coolant well below the boiling point of the coolant (e.g., well below 100 degrees when using water as the coolant). This is accomplished by placing a second thermal resistor (also called a heat choke) 286 between the backplate 204 and the second cooling plate 280.

[0069] The heat choke 286 is shown in further detail with reference to Figure 7 and described below. Briefly, the heat choke 286 may be composed of multiple layers of material having a different thermal conductivity than the metal or alloy used to form the backplate 204. At least one of the layers may be patterned, as described below with reference to Figure 7. With layers of different thermal conductivity, the heat choke 286 gradually impedes heat flow from the backplate 204 to the second cooling plate 280, preventing overheating and boiling of the coolant. Example of a cooling plate and heater used above the faceplate

[0070] 3 shows a top view of the first cooling plate 260 with a heater 262. The first cooling plate 260 is circular. The heater 262 comprises a circular plate with a smaller diameter than the first cooling plate 260. The heater 262 is disposed on top of the first cooling plate 260. The top surfaces of the first cooling plate 260 and the heater 262 are coplanar. The heater 262 is in direct thermal contact with the backplate 204 and the first cooling plate 260. The heater 262 is electrically insulated from the first cooling plate 260 and the backplate 202.

[0071] 2, the heater 262 has a thickness or height that is less than the thickness or height of the first cooling plate 260. The heater 262 is shown as being closer to the backplate 204 than to the faceplate 202. However, the heater 262 can be located closer to the faceplate 202 than to the backplate 204. Alternatively, the heater 262 can be located in a central portion of the first cooling plate 260 such that the heater 262 is equidistant from both the faceplate 202 and the backplate 204.

[0072] A plurality of notches 290-1, 290-2, ..., 290-6 (collectively, notches 290) are provided in the first cooling plate 260 along with the heater 262. A segment 242 (shown in FIG. 5) of the ceramic portion 222 passes through the notches 290. Example of an external heater used above the faceplate

[0073] Figure 4 shows a bottom view of the first cooling plate 260 and the outer heater 270. The bottom view shows in more detail the outer heater 270 and the first thermal resistor 274. Elements identified using the same reference numbers as used in Figures 2 and 3 have already been described with reference to Figures 2 and 3 and therefore will not be described again for the sake of brevity.

[0074] The outer heater 270 surrounds the first cooling plate 260. The outer heater 270 and the first cooling plate 260 lie in a plane parallel to the faceplate 202. The outer heater 270 is generally pie-shaped, although the outer heater 270 may be any other shape. Additionally, the outer heaters 270 may be radially equidistant (i.e., placed along a circle) as shown. Alternatively, the outer heaters 270 may be arranged in a different pattern. For example, one set of the outer heaters 270 may be on a first circle having a first radius, while another set of the outer heaters 270 may be on a second circle having a second radius different from the first radius.

[0075] In the illustrated example, the outer heater 270 is composed of an inner curved portion 300 and an outer curved portion 302. The inner curved portions 300 of all the outer heaters 270 have the same radius. The inner curved portions 300 of all the outer heaters 270 lie on a first circle having a first radius R1. The outer curved portions 302 of all the outer heaters 270 have the same radius. The outer curved portions 302 of all the outer heaters 270 lie on a second circle having a second radius R2>R1. The first and second circles are concentric. The centers of the first and second circles are aligned with the centers of the faceplate 202, the backplate 204, the stem 206, the first cooling plate 260, and the heater 262.

[0076] The first thermal resistor 274 is annular. The inner diameter (ID) of the first thermal resistor 274 is larger than the OD of the first cooling plate 260. The outer diameter (OD) of the first thermal resistor 274 is equal to or smaller than the OD of the faceplate 202 (as shown in FIG. 2). The ID of the first thermal resistor 274 is smaller than the diameter of a first circle having a radius R1 in which the inner curved portions 300 of all the heaters 270 are located. The OD of the first thermal resistor 274 is larger than the diameter of a second circle having a radius R2 in which the outer curved portions 302 of all the heaters 270 are located.

[0077] The first thermal resistor 274 is constructed from a material that has a different (lower) thermal conductivity than the metal or alloy used to form the backplate 204 and the insulating material 272 used to encapsulate the outer heater 270. Thus, the first thermal resistor 274 impedes heat flow from the outer heater 270 to the backplate 204. Gas Distribution Manifold Example

[0078] Figures 5 and 6 show the ceramic portion 222 of the stem 206 in further detail. Figure 5 shows a cross-sectional view of the ceramic portion 222 from a different angle than that shown in Figure 2 to show segments of the ceramic portion 222. Figure 6 shows a cross-sectional view of the ceramic portion 222 in further detail along with adjacent elements of the showerhead 200. In Figures 5 and 6, elements identified using the same reference numbers as used in Figures 1-4 have already been described with reference to Figures 1-4 and therefore will not be described again for the sake of brevity.

[0079] 5 shows segments 242-1, 242-2 (collectively, segments 242) extending radially outward from the base of ceramic portion 222 toward the OD of backplate 204. Although only two segments 242 are shown, showerhead 200 may include multiple segments 242. For example, showerhead 200 may include six segments 242 and six ports 240. In general, showerhead 200 may include multiple segments 242 and respective ports 240. The distal ends of segments 242 extend perpendicular to segments 242 and parallel to the vertical axis of showerhead 200 to form ports 240. Ports 240 are attached to upper surface 205 of faceplate 202.

[0080] Segment 242 includes additional gas passages 250-8 and 250-9 that are not visible in Figure 2. Gas passages 250-8 and 250-9 are in fluid communication with the remainder of gas passage 250 and are an integral part of the gas distribution manifold described above with reference to Figure 2.

[0081] 6 shows segments 242 and ports 240 in further detail. Portions of segments 242 and ports 240 overlap a radially outer portion of first cooling plate 260 and a radially outer portion of heater 262. Ports 240 are attached to upper surface 205 of faceplate 202 such that gas passages 250 in ports 240 are aligned and in fluid communication with respective gas passages 250 in faceplate 202. The overlap of first cooling plate 260, portions of segments 242, and ports 240 prevents overheating of the gas distribution manifold (i.e., elements 222, 242, and 240). Example of a heat choke used between the backplate and the cooling plate

[0082] 7 illustrates an example of a heat choke 286 disposed between the second cooling plate 280 and the backplate 204, as shown in FIG. 2. For example, the heat choke 286 comprises a first plate 330 and a second plate 332. The outer diameters of the first and second plates 330, 332 are equal to or less than the OD of the backplate 204. The first and second plates 330, 332 are constructed from materials having different thermal conductivities, each less than the thermal conductivity of the material comprising the backplate 204.

[0083] For example, if the backplate 204 is made of aluminum, the first plate 330 may be made of stainless steel, and the second plate 332 may be made of a non-metallic material (e.g., a semiconductor material). For example, the thermal conductivity of the first plate 330 is less than that of the backplate 204 and greater than that of the second plate 332. Thus, the first and second plates 330, 332 form a thermal resistor (i.e., heat choke 286) that gradually impedes (i.e., slows) the flow of heat from the backplate 204 to the second cooling plate 280 to prevent overheating of the coolant in the conduit 282. Specifically, the thermal resistor (i.e., heat choke 286) prevents the coolant flowing through the second cooling plate 280 from reaching its boiling point.

[0084] The first plate 330 further comprises recesses 334, which provide air pockets that further increase the thermal resistance of the thermal resistor (i.e., heat choke 286). Specifically, the first plate 330 comprises a plurality of recesses 334-1, 334-2, 334-3, ..., and 334-N, where N is an integer greater than 1 (collectively, recesses 334). The recesses 334 can be located on at least one of the top and bottom surfaces of the first plate 330. The recesses 334 on the top surface of the first plate 330 can be sized, shaped, and quantified such that approximately 65% ​​of the surface area of ​​the top surface of the first plate 330 contacts the bottom surface of the second cooling plate 280.

[0085] Similarly, the recess 334 on the bottom surface of the first plate 330 may be sized, shaped, and sized such that approximately 65% ​​of the surface area of ​​the bottom surface of the first plate 330 contacts the top surface of the second plate 332. Other ratios of contact area of ​​the top and bottom surfaces of the first plate 330 may be used. For example, the contact area of ​​the top and bottom surfaces of the first plate 330 may vary between 50-80%. Additionally, the contact areas of the top and bottom surfaces of the first plate 330 may be different (i.e., not equal).

[0086] More specifically, the first and second plates 330, 332 are constructed from materials having relatively low thermal conductivity. The first plate 330 may have a higher thermal conductivity than the second plate 332. The first and second plates 330, 332 provide a thermal barrier for heat flowing from the backplate 204 to the second cooling plate 280. The second plate 332 provides a thermal barrier for heat flowing from the backplate 204 to the first plate 330, and the first plate 330 provides a thermal barrier for heat flowing from the second plate 332 to the second cooling plate 280. The first and second plates 330, 332 act as heat chokes or thermal resistors in series with one another. Thus, the second plate 332 and the first plate 330 present an increasing thermal barrier or resistance to heat flowing from the backplate 204 to the second cooling plate 280.

[0087] The recesses 334 include air pockets on at least one of the top and bottom surfaces and are spaced apart across the first plate 330 to further enhance the thermal barrier. The stack of first and second plates 330, 332 forms a thermal resistor (i.e., heat choke 286) that prevents the second cooling plate 280 from conducting a relatively large amount of heat from the backplate 204, thereby allowing the outer heater 270 to operate at a relatively high capacity.

[0088] The thermal resistors (i.e., heat chokes 286) also keep the coolant (e.g., water) in the conduits 282 from approaching its boiling point due to heat flow. Thus, the second cooling plate 280, the outer heater 270, the heat chokes 286, the first cooling plate 260, and the heater 262 provide a balance between heating and cooling the showerhead 200 and minimize temperature gradients across the faceplate 202.

[0089] The first plate 330 may be fabricated as a monolithic plate. Alternatively, the first plate 330 may include three layers: two layers (top and bottom) with recesses 334 (in the form of recesses or slots cut through the layers), and a third layer that is flat (i.e., does not have recesses 334) and is sandwiched between the two layers. The three layers may be bonded together (e.g., brazed or diffusion bonded).

[0090] The recesses 334 can be arranged in a number of ways on at least one of the top and bottom surfaces of the first plate 330. The recesses 334 on the top surface of the first plate 330 may be aligned with the recesses 334 on the bottom surface of the first plate 330. Alternatively, the recesses 334 on the top surface of the first plate 330 may be offset relative to the recesses 334 on the bottom surface of the first plate 330. For example, the recesses 334 on the top surface of the first plate 330 may overlap with at least one of the recesses 334 on the bottom surface of the first plate 330. Alternatively, none of the recesses 334 on the top surface of the first plate 330 may overlap with the recesses 334 on the bottom surface of the first plate 330.

[0091] The recesses 334 on the top and bottom surfaces of the first plate 330 may have any size, shape, and amount, so long as the contact areas of the top and bottom surfaces of the first plate 330 are as described above. For example, the recesses 334 on the top and bottom surfaces of the first plate 330 may be the same size and shape. Alternatively, the recesses 334 on the top surface of the first plate 330 may be a different size and / or shape than the recesses 334 on the bottom surface of the first plate 330. The recesses 334 can be symmetrically or asymmetrically disposed on the top and bottom surfaces of the first plate 330.

[0092] The number of recesses 334 may differ (e.g., lesser or more) than the number shown. The top and bottom surfaces of the first plate 330 may have the same number of recesses 334. Alternatively, the top surface of the first plate 330 may include a different number of recesses 334 than the bottom surface of the first plate 330. The depth of the recesses 334 may be the same or different. The recesses 334 on the top and bottom surfaces of the first plate 330 may have the same depth. Alternatively, the recesses 334 on the top surface of the first plate 330 may have a first depth. The recesses 334 on the bottom surface of the first plate 330 may have a second depth. The depth of the recesses 334 on the top surface of the first plate 330 may vary in a first pattern. The depth of the recesses 334 on the bottom surface of the first plate 330 may vary in a second pattern. Any combination of the above variations may be used.

[0093] The ODs of the first and second plates 330, 332 are less than or equal to the OD of the second cooling plate 280. The thicknesses of the first and second plates 330, 332 may vary depending on process requirements. The first plate 330 may be thicker than the second plate 332. In some applications, the second plate 332 may include a recess in at least one of its top and bottom surfaces and may include any of the variations described above with reference to the first plate 330.

[0094] Additionally, there may be additional permutations and combinations between the recesses of the first and second plates 330, 332. In some applications, the second plate 332 may be constructed from a thermoplastic material (e.g., polyimide). The second plate 332 may include all of the structural features of the first plate 330 described above. The second plate 332 may be used independently (i.e., by itself instead of being used with the first plate 330). Alternatively, in some applications, the second plate 332 may be omitted and the first plate 330 may be constructed from a thermoplastic material (e.g., polyimide).

[0095] Furthermore, although not shown, a third plate having a relatively low thermal conductivity may be used in addition to the first and second plates 330, 332. The third plate may be similar to either of the first and second plates 330, 332, except that the thermal conductivity of the third plate may be different from the first and second plates 330, 332. The third plate may be disposed above, below, or between the first and second plates 330, 332. The thermal conductivity of the third plate may be selected based on the location of the third plate. For example, a third plate disposed below the second plate 332 may have a lower thermal conductivity than the second plate 332. A third plate disposed above the first plate 330 may have a higher thermal conductivity than the first plate 330. A third plate disposed between the first and second plates 330 , 332 may have a thermal conductivity less than the first plate 330 and greater than the second plate 332 .

[0096] The above description is merely exemplary in nature and is not intended to limit the disclosure, its application, or uses. The broad teachings of the disclosure can be embodied in various forms. Thus, although the disclosure includes specific examples, the true scope of the disclosure should not be so limited, since other modifications will become apparent upon review of the drawings, specification, and claims that follow.

[0097] It should be understood that one or more steps in a method may be performed in different orders (or simultaneously) without altering the principles of the present disclosure. Moreover, although each embodiment is described above as having certain features, any one or more of those features described with respect to any embodiment of the present disclosure can be implemented in and / or combined with the features of any other embodiment, even if the combination is not specified. In other words, the embodiments described herein are not mutually exclusive, and substituting one or more embodiments for one another still falls within the scope of the present disclosure.

[0098] Spatial and functional relationships between elements (e.g., between modules, circuit elements, semiconductor layers, etc.) are described using a variety of terms, including "connected," "engaged," "coupled," "adjacent," "next to," "on top of," "above," "below," and "disposed." When a relationship between a first element and a second element is described in the above disclosure, unless specified as "direct," the relationship may be a direct relationship where there are no other intervening elements between the first element and the second element, but there may also be an indirect relationship where there are one or more intervening elements (spatially or functionally) between the first element and the second element. As used herein, the phrase at least one of A, B, and C should be interpreted as meaning the logic (A OR B OR C) using a non-exclusive logical OR, and not as meaning "at least one of A, at least one of B, and at least one of C."

[0099] In some implementations, the controller is part of a system, which may be part of the examples described above. Such systems may include semiconductor processing equipment, including one or more processing tools, one or more chambers, one or more processing platforms, and / or specific processing components (wafer pedestals, gas flow systems, etc.). These systems may be integrated with electronics for controlling the operation of the system before, during, and after processing of a semiconductor wafer or substrate.

[0100] This electronics may be referred to as a "controller" which may control various components or subcomponents of one or more systems. Depending on the processing requirements and / or type of system, the controller may be programmed to control any of the processes disclosed herein, including supply of process gases, temperature settings (e.g., heating and / or cooling), pressure settings, vacuum settings, power settings, radio frequency (RF) generator settings, RF matching circuit settings, frequency settings, flow rate settings, fluid supply settings, position and motion settings, wafer transport in and out of the tool, and wafer transport in and out of other transport tools and / or load locks connected or coupled to the particular system.

[0101] Broadly, a controller may be defined as an electronic device having various integrated circuits, logic, memory, and / or software that receives instructions, issues instructions, controls operations, enables cleaning operations, enables endpoint measurements, etc. Integrated circuits may include chips in the form of firmware that store program instructions, digital signal processors (DSPs), chips defined as application specific integrated circuits (ASICs), and / or one or more microprocessors or microcontrollers that execute program instructions (e.g., software).

[0102] Program instructions may be instructions communicated to the controller in the form of various individual settings (or program files) that define operational parameters for performing a particular process on or for a semiconductor wafer or for a system. The operational parameters, in some embodiments, may be part of a recipe defined by a process engineer to accomplish one or more processing steps during the manufacture of one or more layers, materials, metals, oxides, silicon, silicon dioxide, surfaces, circuits, and / or dies of the wafer.

[0103] The controller, in some embodiments, may be part of or coupled to a computer that is integrated with, coupled to, or otherwise networked to the system, or a combination thereof. For example, the controller may be in the "cloud" and may be all or part of a fab host computer system, allowing remote access of wafer processing. The computer may allow remote access to the system to monitor the current progress of a fabrication operation, examine the history of past fabrication operations, examine trends or performance indicators from multiple fabrication operations, change parameters of a current process, set up processing steps following a current process, or initiate a new process.

[0104] In some examples, a remote computer (e.g., a server) can provide a process recipe to the system over a network, which may include a local network or the Internet. The remote computer can include a user interface that allows for entry or programming of parameters and / or settings. These parameters and / or settings are then communicated from the remote computer to the system. In some examples, the controller receives instructions in the form of data, where the data specifies parameters for each processing step that is performed during one or more operations. It should be understood that the parameters can be specific to the type of process being performed and the type of tool that the controller is configured to couple to or control.

[0105] Thus, as described above, the controller may be distributed, such as by having one or more separate controllers networked together and operating toward a common purpose, such as the processes and controls described herein. An example of a distributed controller for such purposes would be one or more integrated circuits on the chamber that communicate with one or more integrated circuits located remotely (at the platform level or as part of a remote computer) that in combination will control the process in the chamber.

[0106] Exemplary systems may include, but are not limited to, a plasma etch chamber or module, a deposition chamber or module, a spin rinse chamber or module, a metal plating chamber or module, a cleaning chamber or module, a bevel edge etch chamber or module, a physical vapor deposition (PVD) chamber or module, a chemical vapor deposition (CVD) chamber or module, an atomic layer deposition (ALD) chamber or module, an atomic layer etch (ALE) chamber or module, an ion implantation chamber or module, a tracking chamber or module, and any other semiconductor processing system related to or usable in the fabrication and / or manufacturing of semiconductor wafers.

[0107] As described above, depending on the process step or steps being performed by the tool, the controller may communicate with one or more of the other tool circuits or modules, other tool components, cluster tools, other tool interfaces, adjacent tools, nearby tools, tools located throughout the factory, a main computer, another controller, or tools used for material transport to and from containers of wafers to and from tool locations and / or load ports within a semiconductor production factory.

Claims

1. 1. A showerhead for a substrate processing system, comprising: A back plate made of a metal material; a faceplate constructed from a ceramic material; a first cooling plate disposed between the backplate and a central region of the faceplate; a plurality of heaters disposed between the backplate and a peripheral region of the faceplate; Equipped with a shower head.

2. 10. The showerhead of claim 1, The showerhead, wherein the first cooling plate and the plurality of heaters are in direct thermal contact with the faceplate.

3. 10. The showerhead of claim 1, The first cooling plate is in direct thermal contact with the backplate.

4. 10. The showerhead of claim 1, the first cooling plate comprises a material having a higher thermal conductivity than the metallic material of the backplate.

5. 10. The showerhead of claim 1, The showerhead, wherein the backplate is made of aluminum or an alloy and the first cooling plate is made of copper.

6. 10. The showerhead of claim 1, The showerhead, wherein the first cooling plate and the plurality of heaters are in a plane parallel to the faceplate.

7. 10. The showerhead of claim 1, The plurality of heaters surround the first cooling plate.

8. 10. The showerhead of claim 1, The showerhead, wherein each heater of the plurality of heaters is controlled independently from the remaining heaters of the plurality of heaters.

9. 10. The showerhead of claim 1, a portion of each of the plurality of heaters in direct contact with the faceplate, and a remaining portion of each of the plurality of heaters is encapsulated in an electrically insulating and thermally conductive material.

10. 10. The showerhead of claim 1, The showerhead further comprising a layer of thermally resistant material disposed between the plurality of heaters and the backplate, the thermally resistant material having a lower thermal conductivity than the backplate.

11. 11. The showerhead of claim 10, the layer is annular in shape with an inner diameter greater than a diameter of the first cooling plate and an outer diameter equal to or less than a diameter of the faceplate.

12. 10. The showerhead of claim 1, The showerhead, wherein a diameter of the first cooling plate is equal to or greater than half the diameter of the faceplate.

13. 10. The showerhead of claim 1, The showerhead, wherein the heaters are arranged along a circle having a diameter equal to or smaller than a diameter of the faceplate.

14. 10. The showerhead of claim 1, The first cooling plate comprises a heater.

15. 15. The showerhead of claim 14, The showerhead, wherein the heater is a low-output heater compared to the plurality of heaters.

16. 15. The showerhead of claim 14, The heater is in direct thermal contact with at least one of the backplate and the faceplate.

17. 10. The showerhead of claim 1, The showerhead further comprising a second cooling plate disposed on the backplate, the second cooling plate comprising cooling channels for circulating a coolant.

18. 20. The showerhead of claim 17, the showerhead further comprising a layer of thermally resistant material disposed between the backplate and the second cooling plate, the thermally resistant material having a lower thermal conductivity than the backplate.

19. 20. The showerhead of claim 17, 11. The showerhead of claim 10, further comprising: a plurality of layers of thermally resistant material disposed between the backplate and the second cooling plate, the thermally resistant material having a lower thermal conductivity than the backplate, the thermal conductivity of the layers increasing from the backplate to the second cooling plate.

20. 20. The showerhead of claim 19, At least one of the layers includes a pattern of features that provide air pockets.

21. 10. The showerhead of claim 1, The showerhead further comprising a stem comprising a metal portion and a ceramic portion, the ceramic portion embedded within the metal portion and the backplate.

22. 22. The showerhead of claim 21, the ceramic portion comprises a plurality of segments extending radially from the ceramic portion, distal ends of the segments extending perpendicular to the segments to the faceplate.

23. 23. The showerhead of claim 22, the distal end extending through a notch in the first cooling plate to the faceplate.

24. 23. The showerhead of claim 22, the stem comprises a gas inlet, and the metal portion, the ceramic portion, and the plurality of segments comprise gas passages in fluid communication with the gas inlet.

25. 25. The showerhead of claim 24, The faceplate includes a plurality of through holes, the gas passages being in fluid communication with the through holes.

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