Baffle for providing uniform process gas flow on substrate and around susceptor

Abstract

A substrate processing chamber includes a susceptor and a shutter. The susceptor is disposed in the substrate processing chamber. The base comprises a base part and a rod part. The base part is larger than the rod part in diameter. A baffle plate is disposed around the susceptor to direct gas supplied to the substrate processing chamber to flow around the susceptor, from a periphery of a base portion of the susceptor to a stem portion of the susceptor, and to one or more discharge ports of the substrate processing chamber.

Description

Cross - Reference to Related Applications

[0001] This application claims priority to U.S. Provisional Application No. 63 / 415,792, filed on October 13, 2022. The entire disclosure of the above application is incorporated herein by reference. Technical Field

[0002] The present disclosure generally relates to substrate processing systems, and more particularly, to a baffle for providing a uniform process gas flow over a substrate and around a pedestal in a substrate processing system. Background Art

[0003] The background description provided herein is for the purpose of generally presenting the background of the disclosure. The work of the currently named inventors within the scope described in this background art section, as well as aspects of the specification that were not determined to be prior art at the time of filing the application, are neither expressly nor impliedly admitted to be prior art to the present disclosure.

[0004] Atomic layer deposition (ALD) is a thin - film deposition method that sequentially performs gaseous chemical processes to deposit a thin film on the surface of a material (such as the surface of a substrate like a semiconductor wafer). Most ALD processes use at least two chemical substances called precursors (reactants), with each precursor reacting with the surface of the material in a sequential and self - limiting manner. For example, a typical ALD process includes a series of dosing and purging steps that are performed sequentially and repeatedly. By repeatedly exposing to different precursors, a thin film is gradually deposited on the surface of the material.

[0005] Thermal ALD (T - ALD) processes are typically performed in a heated processing chamber. A vacuum pump and a controlled flow of inert gas are used to maintain the processing chamber at a pressure below atmospheric pressure. The substrate to be coated is placed in the processing chamber, and the temperature of the substrate and the processing chamber is allowed to reach equilibrium before starting the ALD process. Plasma - enhanced ALD (PEALD) processes use plasma during the dosing step. The plasma can be generated in - situ in the processing chamber. Alternatively, plasma can be generated away from the processing chamber and supplied to the processing chamber. Summary of the Invention

[0006] A substrate processing chamber includes a pedestal and a baffle. The pedestal is disposed in the substrate processing chamber. The pedestal includes a base portion and a stem portion. The diameter of the base portion is greater than the diameter of the stem portion. The baffle is disposed around the pedestal to direct the gas flow supplied to the substrate processing chamber around the pedestal from the periphery of the base portion of the pedestal to the stem portion of the pedestal and towards one or more discharge ports of the substrate processing chamber.

[0007] In an additional feature, the baffle is annular and bowl - shaped.

[0008] In an additional feature, regardless of the position of the discharge port in the substrate processing chamber, the gas flow around the susceptor is uniform.

[0009] In an additional feature, the substrate processing chamber further includes a substrate, which is placed on the susceptor. Regardless of the position of the discharge port in the substrate processing chamber, the gas flow is uniform on the substrate.

[0010] In an additional feature, the baffle is connected to the bottom of the substrate processing chamber.

[0011] In an additional feature, the baffle includes a plurality of legs connected to the bottom of the substrate processing chamber.

[0012] In an additional feature, the baffle includes a plurality of legs connected to the bottom of the substrate processing chamber. The gas flow flows towards the discharge port of the substrate processing chamber through the gap between the legs and the bottom of the substrate processing chamber.

[0013] In an additional feature, the outer edge of the baffle contacts the side wall of the substrate processing chamber. The interior of the baffle is separated from the susceptor.

[0014] In an additional feature, the lower part of the base portion of the susceptor tapers radially inward. The interior of the baffle extends radially inward towards the lower part of the base portion of the susceptor and the rod portion of the susceptor.

[0015] In an additional feature, the baffle includes a flange and a base portion. The flange extends radially outward from the lower part of the base portion of the baffle. The base portion of the baffle extends radially inward towards the rod portion of the susceptor.

[0016] In an additional feature, the upper part of the base portion of the baffle extends further radially inward towards the rod portion of the susceptor than the base portion of the baffle.

[0017] In an additional feature, the baffle is integrally formed.

[0018] In an additional feature, the baffle further includes a plurality of legs connected to the bottom of the substrate processing chamber. The baffle and the legs are integrally formed.

[0019] In an additional feature, the upper part of the base portion of the baffle extends further radially inward towards the rod portion of the susceptor than the base portion of the baffle, and the baffle further includes a plurality of legs connected to the bottom of the substrate processing chamber. The baffle and the legs are integrally formed.

[0020] In an additional feature, the baffle includes a plurality of legs connected to the bottom of the substrate processing chamber. The substrate processing chamber further includes: an annular plate disposed on the bottom of the substrate processing chamber and around the rod portion of the pedestal to support a plurality of lift pins for lifting a substrate disposed on the pedestal. The inner diameter of the base portion of the baffle is smaller than the outer diameter of the base portion of the pedestal and larger than the outer diameters of the rod portion and the annular plate. The height of the legs is greater than or equal to the thickness of the annular plate. The gas flow flows around the outer diameter of the annular plate and flows through the gap between the legs and the bottom of the substrate processing chamber to the discharge port of the substrate processing chamber.

[0021] In an additional feature, the outer diameter of the flange contacts the side wall of the substrate processing chamber. The inner diameter of the flange is smaller than or equal to the outer diameter of the base portion of the pedestal. The inner diameter of the base portion of the baffle is smaller than the inner diameter of the flange, smaller than the outer diameter of the base portion of the pedestal, and larger than the outer diameter of the rod portion.

[0022] In an additional feature, the upper portion of the base portion of the baffle extends radially inward further toward the rod portion of the pedestal than the base portion of the baffle. The outer diameter of the flange contacts the side wall of the substrate processing chamber. The inner diameter of the flange is smaller than or equal to the outer diameter of the base portion of the pedestal. The inner diameters of the base portion and the upper portion of the base portion of the baffle are smaller than the inner diameter of the flange, smaller than the outer diameter of the base portion of the pedestal, and larger than the outer diameter of the rod portion.

[0023] In an additional feature, the substrate processing chamber further includes an annular plate disposed on the bottom of the substrate processing chamber and around the rod portion of the pedestal to support a plurality of lift pins for lifting a substrate disposed on the pedestal. The outer diameter of the flange contacts the side wall of the substrate processing chamber. The inner diameter of the flange is smaller than or equal to the outer diameter of the base portion of the pedestal. The inner diameter of the base portion of the baffle is smaller than the inner diameter of the flange, smaller than the outer diameter of the base portion of the pedestal, and larger than the outer diameters of the rod portion and the annular plate.

[0024] In an additional feature, the substrate processing chamber further includes an annular plate that is disposed at the bottom of the substrate processing chamber and surrounds the rod portion of the pedestal to support a plurality of lift pins for lifting a substrate disposed on the pedestal. The upper portion of the base portion of the baffle extends further radially inwardly towards the rod portion of the pedestal than the base portion of the baffle. The outer diameter of the flange contacts the sidewall of the substrate processing chamber. The inner diameter of the flange is less than or equal to the outer diameter of the base portion of the pedestal. The inner diameters of the base portion of the baffle and the upper portion of the base portion are less than the inner diameter of the flange, less than the outer diameter of the base portion of the pedestal, and greater than the outer diameters of the rod portion and the annular plate.

[0025] In an additional feature, the baffle includes a plurality of legs. The legs include through holes for inserting fasteners to fix the baffle to the bottom of the substrate processing chamber.

[0026] In an additional feature, the substrate processing chamber further includes a showerhead and a vacuum pump. The showerhead is disposed above the pedestal to supply gas into the substrate processing chamber during processing of a substrate disposed on the pedestal and during cleaning of the substrate processing chamber. The vacuum pump is coupled to the discharge port to evacuate gas from the substrate processing chamber during the processing and the cleaning.

[0027] Based on the detailed description, claims, and drawings, a further scope of applicability of the present disclosure will become apparent. The detailed description and specific examples are for illustrative purposes only and are not intended to limit the scope of the present disclosure. Description of the Drawings

[0028] The present disclosure will be more fully understood from the detailed description and the drawings, in which:

[0029] Figure 1 An example of a substrate processing system having a processing chamber including a baffle according to the present disclosure is shown;

[0030] Figure 2 A processing chamber including a baffle and a uniform gas flow provided by the baffle in the processing chamber are shown;

[0031] Figure 3 A cross-sectional view of the baffle is shown;

[0032] Figure 4 A top perspective view of the baffle is shown, which shows the design, shape, and geometry of the baffle;

[0033] Figure 5 A bottom perspective view of the baffle is shown, which shows the design, shape, and geometry of the baffle;

[0034] Figure 6 shows a top plan view of a baffle, which shows the design, shape, and geometry of the baffle; and

[0035] Figure 7 shows a bottom plan view of the baffle, which shows the design, shape, and geometry of the baffle.

[0036] In the drawings, reference numerals may be reused to identify similar and / or identical elements. DETAILED DESCRIPTION

[0037] In most substrate processing systems (also referred to as tools), a processing chamber includes one or more exhaust ports through which process gases supplied to the processing chamber are pumped out using a pump. Generally, the exhaust ports are not uniformly (symmetrically) arranged in the processing chamber. Due to the arrangement (such as position) of the exhaust ports in the processing chamber, the process gas flow around the pedestal in the processing chamber may be non-uniform. The non-uniform flow of the process gas around the pedestal affects the distribution of the process gas on the surface of the substrate disposed on the pedestal and the distribution of the process gas beyond the edge of the pedestal during substrate processing.

[0038] The present disclosure provides a baffle arranged around a pedestal to achieve a uniform process gas flow around the substrate surface and the pedestal. The design (shape) of the baffle makes the process gas flow around the pedestal in the processing chamber uniform even if the exhaust ports are non-uniformly (asymmetrically) arranged in the processing chamber. The design (shape) of the baffle can limit the risk of deposition on the baffle during substrate processing, which would otherwise cause a change in processing performance.

[0039] Without the baffle, sufficient uniformity of the flow around the pedestal and the substrate cannot be achieved, especially when the exhaust ports are non-uniformly (asymmetrically) arranged in the processing chamber. The non-uniform flow causes non-uniform deposition on the substrate. The baffle according to the present disclosure has a bowl-shaped geometry. This geometry limits the flow of the process gas between the baffle and the inner wall of the processing chamber. Due to the limitation provided by the baffle, uniform pumping of the process gas can be achieved even in the case of non-uniform exhaust port arrangement. The baffle does not use restricted flow channels (such as holes) inside the baffle. Therefore, the baffle eliminates the risk of deposit accumulation, which would otherwise cause a change in process performance over time. The baffle design is symmetric and there is no risk of improper installation as described below, which would otherwise result in poor performance.

[0040] The baffle according to the present disclosure can redirect the flow of the process gas from the edge of the pedestal to the center of the pedestal rod and then collectively to the discharge port without providing holes in the baffle to define the flow channels. The absence of holes in the baffle not only eliminates the risk of deposit accumulation but also eliminates cavities that may be difficult to clean, resulting in particle reduction. The baffle includes fixing features (e.g., feet with holes) to fasten the baffle to the processing chamber. The fixing features ensure the static positioning of the baffle and also reduce the risk of metal-to-metal scratching, which otherwise can lead to particle contamination and migration of metal components to the surface of the substrate. The baffle has a simple and symmetric geometry. The symmetric design of the baffle prevents incorrect installation of the baffle in the processing chamber, which otherwise can lead to performance issues. These and other features of the baffle will be described in detail below.

[0041] The present disclosure is organized as follows. Referring to Figure 1 An example of a substrate processing system including a processing chamber is shown and described. Figure 1 The baffle in the processing chamber is schematically shown. Figure 2 The processing chamber including the baffle is shown and further described in detail. Figure 2 The design of the baffle and the uniform gas flow around the pedestal are shown and described. Figure 2-7 The geometry of the baffle is shown and described in detail.

[0042] Figure 1 An example of a substrate processing system 100 is shown. The substrate processing system 100 includes a processing chamber 102. The processing chamber 102 includes a pedestal 104 and a showerhead 106. During processing, a substrate 108 is placed on the pedestal 104. During substrate processing, the showerhead 106 supplies one or more process gases to the processing chamber 102.

[0043] The pedestal 104 includes a base portion 110 and a stem portion 112. The base portion 110 is generally cylindrical and has a diameter larger than the substrate 108. The stem portion 112 can be cylindrical or in the shape of the letter "Y", with the flared or forked end of the "Y" connected to the base portion 110. The other end of the stem portion 112 is connected to the bottom of the processing chamber 102. The diameter of the stem portion 112 is smaller than the base portion 110. A pedestal lift assembly 113 is coupled to the stem portion 112 to move the pedestal 104 relative to the showerhead 106.

[0044] The base portion 110 includes a heater 114 to heat the substrate 108. The base portion 110 also includes a cooling channel (not shown) to circulate coolant supplied from a coolant supply source 116 to regulate the temperature of the susceptor 104. The base portion 110 includes a temperature sensor 118 to sense the temperature of the susceptor 104. The temperature sensor 118 is connected to a temperature controller 119. Based on the temperature detected by the temperature sensor 118, the temperature controller 119 controls the heater 114 and the coolant flowing into the cooling channel of the base portion 110 from the coolant supply source 116 to regulate the temperature of the susceptor 104.

[0045] The showerhead 106 includes a base portion 120 and a stem portion 122. The base portion 120 is cylindrical and extends radially across the substrate 108. The diameter of the base portion 120 is larger than the diameter of the substrate 108. On the surface facing the substrate, the base portion 120 includes a panel that contains a plurality of holes (not shown), through which one or more process gases enter the processing chamber 102 during substrate processing. The stem portion 122 is also generally cylindrical and has a diameter smaller than that of the base portion 120. The first end of the stem portion 122 is connected to the central portion of the base portion 120. The second end of the stem portion 122 is connected to the top plate of the processing chamber 102.

[0046] Although not shown, the base portion 120 may include a heater to heat the process gas. The base portion 120 may also include a cooling channel to circulate coolant supplied from a coolant supply source 116 to regulate the temperature of the showerhead 106. The base portion 120 includes a temperature sensor 124 to sense the temperature of the showerhead 106. The temperature sensor 124 is connected to the temperature controller 119. Based on the temperature sensed by the temperature sensor 124, the temperature controller 119 controls the heater and the flow rate of the coolant flowing into the cooling channel of the base portion 120 from the coolant supply source 116 to regulate the temperature of the showerhead 106.

[0047] The gas delivery system 130 supplies one or more gases to the processing chamber 102. The gas delivery system 130 includes a plurality of gas sources 132-1, 132-2,......, 132-N (collectively referred to as gas sources 132), where N is a positive integer. The gas sources 132 supply various gases, including process gases, purge gases, precursors, cleaning gases, etc. The gas delivery system 130 includes a plurality of valves 134-1, 134-2,......, 134-N (collectively referred to as valves 134). The valves 134 are connected to the gas sources 132 and control the gas flow rate supplied by the gas sources 132.

[0048] The gas delivery system 130 includes a plurality of mass flow controllers (MFCs) 136-1, 136-2, ..., 136-N (collectively referred to as MFC 136). The MFC 136 is connected to the valve 134 and controls the mass flow of the gas supplied by the gas source 132 via the valve 134. The gas delivery system 130 includes a manifold 138. The manifold 138 is connected to the MFC 136 and the showerhead 106. The manifold 138 supplies gas to the showerhead 106.

[0049] During substrate processing, certain processes may use one or more vaporized precursors. Thus, although not shown, the substrate processing system 100 may further include a vaporized precursor supply source to supply one or more vaporized precursors. The vaporized precursor supply source may also be connected to the manifold 138. When in use, the manifold 138 may supply one or more vaporized precursors supplied by the vaporized precursor supply source to the showerhead 106.

[0050] In some processes, a plasma may be used during substrate processing. Although not shown, the substrate processing system 100 may further include a radio frequency (RF) power source to supply RF power to generate a plasma. For example, the RF power source may supply RF power to the showerhead 106 with the pedestal 104 grounded or floating. Alternatively, the RF power source may supply RF power to the pedestal 104 with the showerhead grounded or floating. In either case, when one or more process gases are supplied into the processing chamber 102 via the showerhead 106, the RF power supplied by the RF power source excites the process gases in the processing chamber 102 to generate a plasma between the showerhead and the substrate 108. In some processes, the plasma may be generated remotely from the (outside of) the processing chamber 102 and supplied to the processing chamber 102 instead of being generated in the processing chamber 102.

[0051] The processing chamber 102 includes a plurality of exhaust ports arranged around the lower perimeter of the sidewall of the processing chamber 102 (e.g., Figure 2 the exhaust port 103 is shown). The exhaust port is coupled to a foreline 144 connected to the processing chamber 102. The substrate processing system 100 further includes a vacuum pump 140 that is connected to the processing chamber 102 via the foreline 144 through a valve 142. During substrate processing, the vacuum pump 140 maintains the pressure (e.g., vacuum) inside the processing chamber 102. The vacuum pump 140 may also evacuate the process gases and reaction by-products in the processing chamber 102 during substrate processing and during cleaning of the processing chamber 102.

[0052] When the substrate 108 is clamped to the susceptor 104 using vacuum clamping, the vacuum pump 140 also provides the vacuum clamping. Although not shown, the substrate can be clamped to the susceptor 104 using other clamping methods (e.g., electrostatic clamping provided by electrodes in the base portion 110 of the susceptor 104, mechanical clamping, etc.). The processing chamber 102 also includes a controller 150. The controller 150 controls all elements of the substrate processing system 100 described above.

[0053] The processing chamber 102 also includes a baffle 160. The baffle 160 is only schematically shown in Figure 1 . The baffle 160 will be shown and described in further detail with reference to Figure 2-7 . Generally, the exhaust ports are not uniformly (symmetrically) arranged in the processing chamber 102. Due to the arrangement (e.g., position) of the exhaust ports in the processing chamber 102, the process gas flow around the susceptor 104 may be non-uniform. The non-uniform flow of the process gas around the susceptor 104 can affect the distribution of the process gas on the surface of the substrate 108 during substrate processing and beyond the edge of the susceptor 104.

[0054] Therefore, the baffle 160 is disposed around the susceptor 104 to achieve a uniform gas flow over the substrate 108 and around the susceptor 104. As shown and described in further detail with reference to Figure 2-5 , the design (shape) of the baffle 160 is to achieve a uniform gas flow over the substrate 108 and around the susceptor 104. The design (shape) of the baffle 160 equalizes the gas flow around the susceptor 104, regardless of the arrangement (position) of the exhaust ports. In addition, the design (shape) of the baffle 160 can limit the risk of deposition on the baffle 160 during substrate processing, which would otherwise cause changes in process performance.

[0055] In the absence of the baffle 160, the flow uniformity around the susceptor 104 and around the substrate 108 cannot be sufficiently uniform. Non-uniform flow can lead to non-uniform deposition on the substrate 108. As detailed below, the baffle 160 has a bowl-shaped geometry, which can limit the flow of process gas and reaction by-products between the baffle 160 and the inner wall of the processing chamber 102. Due to the restriction provided by the baffle 160, uniform pumping of the process gas can be achieved in the case of non-uniform arrangement of the exhaust ports. The baffle 160 does not use restricted flow channels (e.g., holes) inside the baffle 160. Therefore, the baffle 160 eliminates the risk of deposit accumulation, which would otherwise cause changes in process performance over time. The design of the baffle 160 is symmetric and there is no risk of improper installation as described below, which would otherwise result in poor performance.

[0056] Specifically, in the case where no holes or other flow-restricting features (such as holes) are provided on the baffle 160, as detailed below, the baffle 160 can redirect the flow of the process gas from the edge of the susceptor 104 to the center of the stem 112 of the susceptor 104 and then collectively flow to the discharge port. The absence of holes on the baffle 160 not only eliminates the risk of sediment accumulation but also eliminates cavities that may be difficult to clean, thereby achieving particle reduction. As Figure 2-7 shown, the baffle 160 includes fixing features (legs with through-holes) to fasten the baffle 160 to the processing chamber 102. The fixing features of the baffle 160 can ensure the static positioning of the baffle 160 in the processing chamber 102. Although both the baffle 160 and the walls of the processing chamber 102 are made of metallic materials, the fixing features of the baffle 160 also reduce the risk of metal-to-metal scratching due to friction between the baffle 160 and the walls of the processing chamber 102, which would otherwise cause particle contamination and migration of metal components to the surface of the substrate 108. The symmetric design of the baffle 160 prevents incorrect installation of the baffle 160, which would otherwise lead to performance issues. These and other features of the baffle will be described in detail below with reference to Figure 2-7 .

[0057] Figure 2 FIG. shows the processing chamber 102 including the baffle 160, where the design of the baffle 160 and the uniform gas flow around the susceptor 104 are described in more detail. Figure 2 The elements in Figure 1 have been shown and will not be described again for the sake of brevity. Other elements shown in Figure 2 will be described below.

[0058] In addition to the baffle 160, Figure 2 two other elements not shown in Figure 1 are also shown. First, the processing chamber 102 includes a cylindrical block 170 surrounding the stem 112 of the susceptor 104. When the susceptor 104 is moved up and down by the susceptor lift assembly 113, the cylindrical block 170 mates with the stem 112 of the susceptor 104 and provides a seal for the processing chamber 102.

[0059] Second, the processing chamber 102 includes a lift pin assembly. The lift pin assembly includes a lift pin mounting plate 180 and a plurality of lift pins arranged on the lift pin mounting plate 180. For example, three lift pins 182-1, 182-2, and 182-3 can be used (the third lift pin 182-3 is not visible in the shown view and is therefore not shown but exists). The lift pins 182-1, 182-2, and 182-3 are collectively referred to as the lift pins 182.

[0060] The lift pin mounting plate 180 is an annular plate that surrounds the cylindrical block 170. The lift pin mounting plate 180, together with the baffle 160, guides the air flow towards the discharge port, which will be described in further detail below. The lift pin 182 passes through the base portion 110 of the base 104. When the base 104 is moved up and down by the base lift assembly 113, the lift pin 182 can lower and raise the substrate 108 relative to the base 104, as shown below.

[0061] When the substrate 108 is to be loaded into the processing chamber 102, the base 104 is lowered so that the top end of the lift pin 182 protrudes above the base portion 110 of the base 104. A computer-controlled robotic arm (not shown) loads the substrate 108 into the processing chamber 102, and the substrate 108 is positioned on the top end of the lift pin 182. After the robotic arm retracts, the base 104 moves upward so that the top end of the lift pin 182 retracts below the upper surface of the base portion 110 of the base 104, and the substrate 108 is positioned on the upper surface of the base portion 110 of the base 104.

[0062] After processing, when the substrate 108 is to be removed from the processing chamber 102, the base 104 is lowered so that the top end of the lift pin 182 protrudes above the base portion 110 of the base, and the substrate 108 is positioned on the top end of the lift pin 182. The robotic arm inserts into the gap between the substrate 108 and the upper surface of the base portion 110 of the base 104, and the substrate 108 is removed from the processing chamber 102.

[0063] Before detailing the baffle 160, an example of the geometry of the base portion 110 of the base 104 will be detailed. For example, the base portion 110 of the base 104 includes an upper portion 111 and a lower portion 115. The upper portion 111 of the base 110 is cylindrical. During processing, the substrate 108 is positioned on the upper portion 111 of the base portion 110. The lower portion 115 of the base portion 110 extends downward from the bottom of the upper portion 111 towards the bottom of the processing chamber 102, as shown below.

[0064] For example, the lower portion 115 of the base portion 110 has a trapezoidal cross-section. Specifically, in the example shown, the lower portion 115 of the base portion 110 tapers radially inwards by a first distance from the bottom of the upper portion 111 towards the stem portion 112 of the base 104. The lower portion 115 of the base portion 110 tapers downward by a first distance towards the bottom of the processing chamber 102. After the first distance, the lower portion 115 of the base portion 110 extends radially inwards and is parallel to the upper portion 111. After the first distance, the lower portion 115 of the base portion 110 extends towards and then upward towards the stem portion 112 of the base 104. Thus, the upper end of the lower portion 115 has the same outer diameter (OD) as the upper portion 111, but the diameter of the lower end of the lower portion 115 is smaller than the diameter of the upper end of the lower portion 115.

[0065] Now refer to Figure 2-7Describe the geometry of baffle 160 in detail. Figure 2 and Figure 3 Shows a cross-sectional view of baffle 160. Figure 4 and Figure 5 Show the top and bottom perspective views of baffle 160, respectively. Figure 6 and Figure 7 Show the top and bottom plan views of baffle 160, respectively. Different components of baffle 160 can be seen in different Figure 2-7 views. Figure 3-7 Shows all components or features of baffle 160 described below. Not all elements or features of baffle 160 are visible in each Figure 3-7 view. Only the elements or features of baffle 160 that are visible in Figure 3-7 are labeled in Figure 3-7 . Therefore, the following description refers to Figure 3-7 for simplicity and will not be described separately.

[0066] If the base portion of base 104 is fully cylindrical (i.e., the upper part 111 and the lower part 115 of base portion 110 are cylindrical), the geometry of baffle 160 described below can also be the same. Even if the base portion of base 104 is fully cylindrical, baffle 160 can guide the gas flow as described below.

[0067] Baffle 160 is generally an annular and bowl-shaped structure. Specifically, baffle 160 includes a flange (also referred to as an annular portion) 200 and a base portion 202. Baffle 160 is integrally formed. Baffle 160 is manufactured as a single workpiece including flange 200 and base portion 202. Flange 200 extends radially outward from base portion 202, forming a flange-like structure. Base portion 202 is annular. As detailed below, base portion 202 extends downward and radially inward from the bottom of flange 200.

[0068] The outer diameter of flange 200 is greater than the outer diameter of the base portion 110 of base 104 (i.e., the outer diameter of the upper part 111 of base portion 110 of base 104). Flange 200 contacts the side wall of processing chamber 102. The inner diameter (ID) of flange 200 matches the outer diameter of the upper part 111 of base portion 110 of base 104. In some examples, although not shown, since baffle 160 is disposed below upper part 111 and adjacent to the tapered lower part 115 of base portion 110, the inner diameter of flange 200 can be smaller than the outer diameter of upper part 111. As shown, the inner diameter of flange 200 can be circular, but it doesn't have to be.

[0069] The base portion 202 extends radially inward a second distance from the bottom of the flange 200 towards the stem portion 112 of the base 104. In the illustrated example, the upper portion 204 of the base portion 202 of the baffle 160 extends radially inward from the inner diameter of the base portion 202 towards the stem portion 112 of the base 104. The upper portion 204 of the base portion 202 of the baffle 160 extends further radially inward towards the stem portion 112 of the base 104 than the remainder of the base portion 202, forming a flange-like structure. The upper portion 204 of the base portion 202 extends a third distance from the base portion 202 towards the stem portion 112 of the base 104. The third distance is less than the second distance.

[0070] In some implementations, the upper portion 204 of the base portion 202 of the baffle 160 may be omitted, but the baffle 160 can still direct gas flow as described below. In some embodiments, the lower portion 115 of the base portion 110 of the base 104 may be cylindrical instead of conical. Additionally, the upper portion 204 of the base portion 202 of the baffle 160 may be omitted, but the baffle 160 can still direct gas flow as described below.

[0071] The upper portion 204 of the base portion 202 of the baffle 160 is parallel to the upper portion 111 of the base portion 110 of the base 104. The upper portion 204 of the base portion 202 is also parallel to the upper surface of the flange 200. The upper surface of the base portion 202 is also parallel to the upper surface of the flange 200. The outer diameter of the base portion 202 may, but need not, be less than the outer diameter of the flange 200. In some examples, although not shown, the outer diameter of the base portion 202 may be the same as the outer diameter of the flange 200.

[0072] The inner diameter of the base portion 202 of the baffle 160 and the upper portion 204 of the base portion 202 of the baffle 160 is less than the inner diameter of the flange 200. The inner diameter of the base portion 202 of the baffle 160 and the upper portion 204 of the base portion 202 is less than the outer diameter of the upper portion 111 of the base portion 110 of the base 104. The inner diameter of the base portion 202 of the baffle 160 and the upper portion 204 of the base portion 202 is greater than the outer diameter of the stem portion 112 of the base 104. The inner diameter of the base portion 202 of the baffle 160 and the upper portion 204 of the base portion 202 is also greater than the outer diameter of the lift pin mounting plate 180.

[0073] In some implementations, although not shown, to further facilitate and enhance the gas flow described below, the upper portion 204 of the base portion 202 of the baffle 160 may taper radially inward and downward towards the bottom of the processing chamber 102. Additionally, although not shown, the upper surface of the base portion 202 may taper radially inward and downward towards the bottom of the processing chamber 102. In some examples, although not shown, one or both of the upper portion 204 and the upper surface of the base portion 202 can taper radially inward and downward at the same or different angles (i.e., having the same or different slopes) towards the bottom of the processing chamber 102.

[0074] The flange 200 and the base portion 202 may have different thicknesses (heights). For example, as shown, the flange 200 can be thicker (greater in height) than the base portion 202. In some examples, although not shown, the flange 200 and the base portion 202 may have the same thickness (height). Thus, due to the geometries of the above-mentioned flange 200 and base portion 202, the baffle 160 is generally annular and bowl-shaped.

[0075] The baffle 160 further includes a plurality of legs. For example, the baffle 160 may include four legs, but any number greater than or equal to two legs may also be used. In Figure 2 the cross-sectional view of the baffle 160 shown and Figure 4 the perspective view of the baffle shown, only two legs 210-1 and 210-2 can be seen. The third and fourth legs 210-3 and 210-4 are not visible in Figure 2 and Figure 4 but are visible (overlapping each other) in the cross-sectional view of the baffle 160 shown in Figure 3 and are separately visible in the perspective view of the baffle 160 shown in Figure 5 . All four legs 210-1, 210-2, 210-3, and 210-4 can be seen in Figure 7 . The legs 210-1, 210-2, 210-3, and 210-4 (and any other legs that may be used but not shown) are collectively referred to as legs 210. The legs 210 may also be integrally formed with the baffle 160.

[0076] The legs 210 extend from the bottom of the base portion 202 of the baffle 160. The legs 210 extend downward toward the bottom of the processing chamber 102. As shown, the legs 210 may extend vertically from the base portion 202. In some examples, although not shown, in order to further facilitate and enhance the gas flow described below, the legs 210 may be inclined and may extend downward and radially outward from the base portion 202 to the bottom of the processing chamber 102. Whether the legs 210 are vertical or inclined, the height of the legs 210 is greater than or equal to the thickness (height) of the lift pin mounting plate 180.

[0077] Through holes are drilled through the base portion 202 and each leg 210. Examples of the through holes are 212-1 and 212-2 in Figure 2 and Figure 3 . Although the leg 210-2 can be seen in Figure 4 , the through hole 212-2 of the leg 210-2 cannot be seen in Figure 4 . Although the leg 210-3 cannot be seen in Figure 4 , the through hole of the leg 210-3 can be seen in Figure 4The through hole 212-3 of the support leg 210-3 can be seen. The third through hole 212-3 and the fourth through hole 212-4 for the third support leg 210-3 and the fourth support leg 210-4 are visible (overlapping each other) in Figure 3 the cross-sectional view of the baffle 160 shown, and are separately visible in Figure 5 the perspective view of the baffle 160 shown. In Figure 6 all four through holes 212-1, 212-2, 212-3 and 212-4 can be seen. The through holes 212-1, 212-2, 212-3 and 212-4 (and any additional through holes that may be used but not shown for any additional support legs) are collectively referred to as the through hole 212.

[0078] Fasteners (not shown) can be inserted into the through hole 212 to fasten the baffle 160 to the bottom of the processing chamber 102. The fasteners can be inserted and fastened from the bottom of the processing chamber 102 or the top of the base portion 202 of the baffle 160. As described above, due to the symmetric design (shape) of the baffle 160, the support legs 210 of the baffle 160 can be fixed at any position on the bottom of the processing chamber 102 without considering the position of the discharge portion in the processing chamber 102 (i.e., regardless of the position of the discharge portion in the processing chamber 102).

[0079] When installed, the upper surface of the flange 200 of the baffle 160 is below the bottom of the upper portion 111 of the base portion 110 of the base 104. The inner diameter of the flange 200 surrounds the lower portion 115 of the base portion 110 of the base 104. The inner diameter of the flange 200 does not contact the lower portion 115 of the base portion 110 of the base 104. Instead, there is a gap between the inner diameter of the flange 200 and the periphery of the lower portion 115 of the base portion 110 of the base 104. The gap separates the inner diameter of the flange 200 from the lower portion 115 of the base portion 110 of the base 104.

[0080] In addition, the upper surface of the base portion 202 of the baffle 160 and the upper portion 204 of the base portion 202 also do not contact the lower portion 115 of the base portion 110 of the base 104. Instead, there is a gap between the lower portion 115 of the base portion 110 of the base 104 and the upper surface of the base portion 202 of the baffle 160 and the upper portion 204 of the base portion 202 of the baffle 160. The gap separates the lower portion 115 of the base portion 110 of the base 104 from the upper surface of the base portion 202 of the baffle 160 and the upper portion 204 of the base portion 202 of the baffle 160.

[0081] In addition, although in Figure 2It is not visible in the figure, but due to the presence of the feet 210, there is a gap between the bottom of the base portion 202 of the baffle 160 and the bottom of the processing chamber 102. Together with the geometry of the baffle 160 described above, these gaps and the other gaps described above promote and enhance the gas flow described below. As described below, the lifting pin mounting plate 180 further promotes and enhances the gas flow.

[0082] As Figure 2 shown, the baffle 160 can promote the gas flow in the processing chamber 102. Specifically, the showerhead 106 feeds the process gas into the processing chamber 102. The vacuum pump 140 (as Figure 1 shown) evacuates the process gas and the reaction by-products generated by the reaction of the process gas with the substrate 108 from the processing chamber 102. The process gas and the reaction by-products flow over the substrate 108, bypass the susceptor 104 and the baffle 160, and are discharged from the discharge port of the processing chamber 102, as described below.

[0083] The process gas delivered by the showerhead 106 uniformly flows over the substrate 108 in the directions shown by the arrows 220-1 and 220-2. The process gas and the reaction by-products uniformly flow between the showerhead 106 and the substrate 108 in the directions shown by the arrows 220-1 and 220-2 towards the sidewalls of the processing chamber 102.

[0084] Then, the process gas and the reaction by-products flow downward towards the bottom of the processing chamber 102 in the directions shown by the arrows 220-3 and 220-4 around the upper portion 111 of the base portion 110 of the susceptor 104. The process gas and the reaction by-products flow through the gap between the sidewall of the processing chamber and the outer diameter of the upper portion 111 of the base portion 110 of the susceptor 104 in the directions shown by the arrows 220-3 and 220-4.

[0085] Subsequently, the process gas and the reaction by-products flow through the gap between the inner diameter of the flange 200 of the baffle 160 and the periphery of the tapered lower portion 115 of the base portion 110 of the susceptor 104. The process gas and the reaction by-products flow downward towards the bottom of the processing chamber 102 in the directions shown by the arrows 220-5 and 220-6.

[0086] Thereafter, the process gas and the reaction by-products flow through the gap between the upper portion 204 of the base portion 202 of the baffle 160 and the bottom periphery of the tapered lower portion 115 of the base portion 110 of the susceptor 104. Specifically, the process gas and the reaction by-products flow downward around the upper portion 204 of the base portion 202 of the baffle 160 towards the bottom of the processing chamber 102 in the directions shown by the arrows 220-7 and 220-8. In addition, due to the action of the lifting pin mounting plate 180, the process gas and the reaction by-products flowing around the upper portion 204 of the base portion 202 of the baffle 160 flow towards the feet 210 of the baffle 160 in the directions shown by the arrows 220-9 and 220-10.

[0087] Subsequently, the process gas and reaction by-products flow through the gap provided by the legs 210 between the bottom of the base portion 202 of the baffle 160 and the bottom of the processing chamber 102 towards the discharge ports, such as the discharge port 103 and any other discharge ports of the processing chamber. Thus, regardless of the position of the legs 210 of the baffle 160 and regardless of the position of the discharge ports in the processing chamber 102, compared with when the baffle 160 is not used, the process gas and reaction by-products can flow evenly around the substrate 108 and the susceptor 104, and are finally discharged from the processing chamber 102 more efficiently via the discharge ports.

[0088] Therefore, the bowl-shaped geometry of the baffle 160 restricts the flow of the process gas and reaction by-products between the baffle 160 and the inner wall of the processing chamber 102. Specifically, the baffle 160 causes the process gas and reaction by-products to flow from the outer edge of the susceptor 104 towards the center of the stem portion 112 of the susceptor 104, and then, as indicated by the arrow and described above, collectively flow towards the discharge ports. Due to the restriction provided by the baffle 160, uniform pumping of the process gas and reaction by-products can be achieved regardless of whether the discharge ports are unevenly (asymmetrically) arranged in the processing chamber 102.

[0089] In addition, since the baffle 160 does not use restricted flow channels (such as holes) inside the baffle 160, the baffle 160 eliminates the risk of sediment accumulation, which would otherwise cause changes in process performance and alter fluid conductivity over time. The absence of holes in the baffle 160 also eliminates cavities that may be difficult to clean, thereby achieving the purpose of reducing particles.

[0090] In addition, the symmetric design (geometry) of the baffle 160 eliminates the risk of improper installation of the baffle in the processing chamber 102, which would otherwise result in poor performance. Specifically, the legs 210 of the baffle 160 ensure the static positioning of the baffle 160 and also reduce the risk of scratching between metals, which would otherwise cause particle contamination and migration of metal components to the surface of the substrate 108.

[0091] The baffle 160 helps to direct the flow of gases and reaction by-products not only during substrate processing but also during the cleaning of the processing chamber 102. For example, during the cleaning of the processing chamber 102, the substrate 108 is not used. In some cleaning processes, a dummy substrate may be used. One or more cleaning gases are supplied into the processing chamber 102 via the showerhead 106. The cleaning gases react with the residual materials deposited throughout the processing chamber 102 during substrate processing. The vacuum pump 140 removes the cleaning gases, the residual materials ejected from the components of the processing chamber 102, and any reaction by-products formed by the reaction of the cleaning gases with the residual materials. The vacuum pump 140 discharges these substances from the processing chamber 102 via the discharge port of the processing chamber 102. As described above, the baffle 160 directs the flow of these substances during the cleaning process.

[0092] The foregoing description is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses. The broad teachings of the disclosure can be implemented in a variety of forms. Thus, while the disclosure includes specific examples, the true scope of the disclosure should not be so limited since other modifications will become apparent upon study of the drawings, the specification, and the appended claims.

[0093] It should be understood that, without changing the principles of the disclosure, one or more steps in a method may be performed in a different order (or simultaneously). Additionally, while each embodiment is described above as having certain features, any one or more of those features described with respect to any embodiment of the disclosure can be implemented in and / or combined with the features of any other embodiment, even if the combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and permutations of one or more of the embodiments with each other remain within the scope of the disclosure.

[0094] Various terms are used to describe the spatial and functional relationships between elements (e.g., between modules, between circuit elements, between semiconductor layers, etc.), and the various terms include "connected", "joined", "coupled", "adjacent", "next to", "on top of", "above", "below", and "disposed". Unless the relationship between the first and second elements is explicitly described as "direct", when such a relationship is described in the foregoing disclosure, the relationship can be a direct relationship where there are no other intermediate elements between the first and second elements, but can also be an indirect relationship where there is one or more intermediate elements between the first and second elements (spatially or functionally). As used herein, the phrase "at least one of A, B, and C" should be interpreted to mean a logical (A or B or C) using a non-exclusive logical OR, and should not be interpreted to mean "at least one of A, at least one of B, and at least one of C".

[0095] In some implementations, the controller is part of a system, which can be part of the above examples. Such systems can include semiconductor processing equipment, which includes one or more processing tools, one or more chambers, one or more platforms for processing, and / or specific processing components (wafer chucks, gas flow systems, etc.). These systems can be integrated with electronics for controlling their operations before, during, and after the processing of semiconductor wafers or substrates. The electronics can be referred to as a "controller", which can control various components or sub-components of one or more systems.

[0096] Depending on the processing requirements and / or system type, the controller can be programmed to control any of the processes disclosed herein, including the delivery of processing 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 delivery settings, position and operation settings, wafer transfer in and out of tools and other transfer tools, and / or load locks that connect or dock with a specific system.

[0097] Broadly speaking, a controller can be defined as electronics that has various integrated circuits, logic, memory, and / or software for receiving instructions, issuing instructions, controlling operations, enabling cleaning operations, enabling endpoint measurements, etc. The integrated circuits can include chips in the form of firmware that stores 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).

[0098] The program instructions can be instructions sent to the controller in the form of various individual settings (or program files), which define the operating parameters for performing a specific process on or for a semiconductor wafer or system. In some embodiments, the operating parameters can be part of a recipe defined by a process engineer to complete one or more processing steps during the fabrication of one or more layers, materials, metals, oxides, silicon, silicon dioxide, surfaces, circuits, and / or die of a wafer.

[0099] In some implementations, the controller can be part of or coupled to a computer that is integrated with the system, coupled to the system, otherwise networked to the system, or a combination thereof. For example, the controller can be in the "cloud" or be all or part of a wafer fab host system, which can permit remote access to wafer processing. The computer can implement remote access to the system to monitor the current progress of a manufacturing operation, examine the history of past manufacturing operations, examine trends or performance criteria of multiple manufacturing operations, change parameters of the current process, set processing steps to follow the current process, or initiate a new process.

[0100] In some examples, a remote computer (such as a server) can provide a process recipe to the system via a network, which can include a local network or the Internet. The remote computer can include a user interface that enables input or programming of parameters and / or settings, which are then sent from the remote computer to the system. In some examples, the controller receives instructions in the form of data that specify the parameters for each processing step to be performed during one or more operations. It should be understood that the parameters can be specific to the type of process to be performed and the type of tool that the controller is configured to interface with or control.

[0101] Thus, as described above, the controller can be distributed, for example, by including one or more discrete controllers that are networked together and work towards a common purpose, such as the processes and controls described herein. An example of a distributed controller for such a purpose is one or more integrated circuits on a chamber that communicate with one or more integrated circuits remotely (such as at the platform level or as part of a remote computer), which are combined to control the process on the chamber.

[0102] Example systems can 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, an orbit chamber or module, and any other semiconductor processing system that can be associated with or used for the manufacture and / or preparation of semiconductor wafers.

[0103] As described above, depending on one or more processing steps to be performed by the tool, the controller can communicate with one or more other tool circuits or modules, other tool components, cluster tools, other tool interfaces, adjacent tools, neighboring tools, tools located throughout the factory, a host computer, another controller, or tools used in the material transport that shuttles wafer containers to and from tool locations and / or load ports in a semiconductor manufacturing facility.

Claims

1. A substrate processing chamber, which comprises: a pedestal disposed in the substrate processing chamber, the pedestal including a base portion and a stem portion, the diameter of the base portion being greater than the diameter of the stem portion; and a baffle disposed around the pedestal to direct gas supplied to the substrate processing chamber to flow around the pedestal from the periphery of the base portion of the pedestal to the stem portion of the pedestal and to one or more discharge ports of the substrate processing chamber.

2. The substrate processing chamber according to claim 1, wherein the baffle is annular and bowl-shaped.

3. The substrate processing chamber according to claim 1, wherein the gas flow around the pedestal is uniform regardless of the position of the discharge port in the substrate processing chamber.

4. The substrate processing chamber according to claim 1, further comprising a substrate placed on the pedestal, wherein the gas flow is uniform on the substrate regardless of the position of the discharge port in the substrate processing chamber.

5. The substrate processing chamber according to claim 1, wherein the baffle is connected to the bottom of the substrate processing chamber.

6. The substrate processing chamber according to claim 1, wherein the baffle includes a plurality of legs connected to the bottom of the substrate processing chamber.

7. The substrate processing chamber according to claim 1, wherein the baffle includes a plurality of legs connected to the bottom of the substrate processing chamber, and wherein the gas flow flows to the discharge port of the substrate processing chamber through a gap between the legs and the bottom of the substrate processing chamber.

8. The substrate processing chamber according to claim 1, wherein the outer edge of the baffle contacts the side wall of the substrate processing chamber, and wherein the interior of the baffle is separated from the pedestal.

9. The substrate processing chamber according to claim 1, wherein the lower portion of the base portion of the pedestal tapers radially inwardly, and wherein the interior of the baffle extends radially inwardly towards the lower portion of the base portion of the pedestal and the stem portion of the pedestal.

10. The substrate processing chamber according to claim 1, wherein the baffle includes a flange and a base portion, wherein the flange extends radially outwardly from the lower portion of the base portion of the baffle, and wherein the base portion of the baffle extends radially inwardly towards the stem portion of the pedestal.

11. The substrate processing chamber according to claim 10, wherein the upper portion of the base portion of the baffle extends further radially inwardly towards the stem portion of the pedestal than the base portion of the baffle.

12. The substrate processing chamber according to claim 10, wherein the baffle is integrally formed.

13. The substrate processing chamber according to claim 10, wherein the baffle further includes a plurality of legs connected to the bottom of the substrate processing chamber, and wherein the baffle and the legs are integrally formed.

14. The substrate processing chamber according to claim 10, wherein an upper portion of the base portion of the baffle extends further radially inwardly toward the rod portion of the susceptor than the base portion of the baffle, the baffle further includes a plurality of legs connected to a bottom of the substrate processing chamber, and wherein the baffle and the legs are integrally formed.

15. The substrate processing chamber according to claim 1, wherein the baffle includes a plurality of legs connected to a bottom of the substrate processing chamber, and the substrate processing chamber further comprises: An annular plate, which is disposed on the bottom of the substrate processing chamber and around the rod portion of the susceptor to support a plurality of lift pins for lifting a substrate disposed on the susceptor; wherein an inner diameter of the base portion of the baffle is smaller than an outer diameter of the base portion of the susceptor, and larger than outer diameters of the rod portion and the annular plate; wherein a height of the legs is greater than or equal to a thickness of the annular plate; and wherein the gas flow flows around an outer diameter of the annular plate and flows through a gap between the legs and the bottom of the substrate processing chamber to an exhaust port of the substrate processing chamber.

16. The substrate processing chamber according to claim 10, wherein: An outer diameter of the flange contacts a sidewall of the substrate processing chamber; An inner diameter of the flange is smaller than or equal to an outer diameter of the base portion of the susceptor; and An inner diameter of the base portion of the baffle is smaller than the inner diameter of the flange, smaller than the outer diameter of the base portion of the susceptor, and larger than an outer diameter of the rod portion.

17. The substrate processing chamber according to claim 10, wherein: An upper portion of the base portion of the baffle extends further radially inwardly toward the rod portion of the susceptor than the base portion of the baffle; An outer diameter of the flange contacts a sidewall of the substrate processing chamber; An inner diameter of the flange is smaller than or equal to an outer diameter of the base portion of the susceptor; and An inner diameter of the base portion and the upper portion of the base portion of the baffle is smaller than the inner diameter of the flange, smaller than the outer diameter of the base portion of the susceptor, and larger than an outer diameter of the rod portion.

18. The substrate processing chamber according to claim 10, which further includes an annular plate, the annular plate being disposed on a bottom of the substrate processing chamber and around the rod portion of the susceptor to support a plurality of lift pins for lifting a substrate disposed on the susceptor, wherein: An outer diameter of the flange contacts a sidewall of the substrate processing chamber; An inner diameter of the flange is smaller than or equal to an outer diameter of the base portion of the susceptor; and An inner diameter of the base portion of the baffle is smaller than the inner diameter of the flange, smaller than the outer diameter of the base portion of the susceptor, and larger than outer diameters of the rod portion and the annular plate.

19. The substrate processing chamber according to claim 10, which further includes an annular plate, the annular plate being disposed on a bottom of the substrate processing chamber and around the rod portion of the susceptor to support a plurality of lift pins for lifting a substrate disposed on the susceptor, wherein: The upper portion of the base portion of the baffle extends further radially inwardly toward the rod portion of the pedestal than the base portion of the baffle; The outer diameter of the flange contacts the sidewall of the substrate processing chamber; The inner diameter of the flange is less than or equal to the outer diameter of the base portion of the pedestal; and The inner diameters of the base portion of the baffle and the upper portion of the base portion are less than the inner diameter of the flange, less than the outer diameter of the base portion of the pedestal, and greater than the outer diameters of the rod portion and the annular plate.

20. The substrate processing chamber according to claim 1, wherein the baffle includes a plurality of legs, and wherein the legs include through holes for inserting fasteners to fix the baffle to the bottom of the substrate processing chamber.

21. The substrate processing chamber according to claim 1, further comprising: a showerhead disposed above the pedestal to supply the gas into the substrate processing chamber during processing of a substrate disposed on the pedestal and during cleaning of the substrate processing chamber; and a vacuum pump coupled to the discharge port to pump the gas out of the substrate processing chamber during the processing and the cleaning.

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