Differential anodization showerhead

Abstract

Various embodiments disclosed herein generally relate to an apparatus having a partially anodized gas distribution showerhead comprising a body having a plurality of gas passages extending from an upstream side to a downstream side, each of the upstream side and the downstream side having a different porosity, wherein each of the plurality of gas passages comprises an orifice hole formed at a center of the body, and wherein the downstream side and a portion of each of the plurality of gas passages comprise an anodized layer disposed on the downstream side and the portion of each of the plurality of gas passages.

Description

[0001] background

[0002] field

[0003] The various embodiments disclosed herein generally relate to an apparatus with a partially differentially anodized gas distribution nozzle.

[0004] Related technical descriptions

[0005] Plasma-enhanced chemical vapor deposition (PECVD) is commonly used to deposit thin films on substrates such as semiconductor substrates, solar panel substrates, flat panel display (FPD) substrates, and organic light-emitting diode (OLED) substrates. PECVD is typically achieved by introducing a process gas from a gas distribution nozzle into a vacuum chamber, which has a substrate mounted on a pedestal. Plasma is excited by applying an RF current from one or more RF sources coupled to the chamber to electrodes within the chamber. The plasma reacts to form a material layer on the surface of the substrate positioned on the pedestal. The design of the gas distribution nozzle and the application of the RF current significantly influence the properties of the plasma.

[0006] Some substrates used in industry are planar substrates, such as rectangular, flexible sheets of glass, plastic, or other materials typically used in the manufacture of flat panel displays, solar panels, OLED devices, and other applications. Materials for forming electronic devices, films, and other structures on planar substrates are deposited onto them through numerous processes, including PECVD. However, inhomogeneities and / or film contamination cause problems with electronic devices formed on planar substrates. Numerous modifications have been made to gas distribution nozzles and / or PECVD process parameters, but improvements in film quality remain a priority.

[0007] Therefore, there is a need in the art for devices with gas distribution nozzles that can mitigate or minimize the problems discussed herein. Summary of the Invention

[0008] The various embodiments disclosed herein generally relate to an apparatus having an anodized gas distribution nozzle. In one embodiment, a gas distribution nozzle is provided, the gas distribution nozzle comprising a body having a plurality of gas passages extending from an upstream side to a downstream side, each of the upstream side and the downstream side having a different porosity, wherein each of the plurality of gas passages includes an orifice hole formed at the center of the body, and wherein a portion of the downstream side and each of the plurality of gas passages includes an anodized layer disposed on the downstream side and a portion of each of the plurality of gas passages.

[0009] In another embodiment, a plasma processing apparatus is disclosed. The apparatus includes: a processing chamber body having walls and a floor; a base disposed within the processing chamber body and movable between a first position and a second position; and one or more strips coupled to the base and coupled to one or more of the floor or the walls. The apparatus also includes a nozzle disposed within the processing chamber body opposite to the base. The nozzle includes a body having a plurality of gas passages extending from an upstream side to a downstream side, each of the upstream and downstream sides having a different porosity, wherein each of the plurality of gas passages includes an orifice formed at the center of the body, and wherein a portion of the downstream side and a portion of each of the plurality of gas passages includes an anodized layer disposed on the downstream side and a portion of each of the plurality of gas passages.

[0010] In another embodiment, a plasma-enhanced chemical vapor deposition (PECVD) apparatus is disclosed. The apparatus includes: a chamber body having multiple walls and a chamber floor; and a base disposed within the chamber body and movable between a first position spaced a first distance from the chamber floor and a second position spaced a second distance from the chamber floor greater than the first distance. The apparatus further includes multiple strips coupled to the base and to one or more of the chamber floor and the multiple walls. The multiple strips are unevenly distributed along the base. The apparatus also includes a gas distribution nozzle disposed within the chamber body, opposite the base, and having multiple gas channels extending through the nozzle. The gas dispensing nozzle includes a body having a plurality of gas passages extending from an upstream side to a downstream side, each of the upstream side and the downstream side having a different porosity, wherein each of the plurality of gas passages includes an orifice formed at the center of the body, and wherein a portion of the downstream side and a portion of each of the plurality of gas passages includes an anodized layer disposed on the downstream side and a portion of each of the plurality of gas passages.

[0011] Brief description of the attached figures

[0012] To gain a more detailed understanding of the features and structures described above in this disclosure, reference can be made to various embodiments to obtain a more specific description of the disclosure briefly outlined above, some of which are illustrated in the accompanying drawings. However, it should be noted that the drawings illustrate only a few typical embodiments of this disclosure and therefore should not be construed as limiting the scope of this disclosure, as many other equivalent embodiments are permissible.

[0013] Figure 1 This is a schematic cross-sectional view of a device according to one embodiment.

[0014] Figure 2 yes Figure 1 A cross-sectional view of a portion of the diffuser, illustrating one embodiment of the anodized layer.

[0015] Figure 3 This is a cross-sectional view of a portion of a diffuser according to another embodiment, showing the anodized layer.

[0016] Figure 4 This is a cross-sectional view of a portion of a diffuser according to another embodiment, showing the anodized layer.

[0017] Figure 5 This is a cross-sectional view of a portion of a diffuser according to another embodiment, showing the anodized layer.

[0018] Figure 6 This is a flowchart describing a method for manufacturing a diffuser as described herein.

[0019] Figure 7 This is a cross-sectional view of a portion of a diffuser according to another embodiment, showing the anodized layer.

[0020] For ease of understanding, the same reference numerals have been used as much as possible to indicate common elements in the figures. It is contemplated that elements disclosed in one embodiment may be advantageously used in several other embodiments without specific description. Detailed Implementation

[0021] The various embodiments disclosed herein generally relate to an apparatus having a gas distribution nozzle that is partially and / or differentially anodized. In some embodiments, the gas distribution nozzle is made of aluminum, with some portions remaining bare aluminum while others are anodized as disclosed herein. Anodizing is provided at portions of the gas distribution nozzle, while portions in peripheral areas remain bare aluminum. In several other embodiments, the gas distribution nozzle includes more than one anodized layer disposed on the gas distribution nozzle. In still other embodiments, the gas distribution nozzle includes different roughnesses and / or porosities on opposing primary surfaces of the gas distribution nozzle.

[0022] The embodiments discussed herein will refer to large-area PECVD chambers manufactured and sold by AKT America, a subsidiary of Applied Materials, Inc., Santa Clara, CA. It should be understood that the various embodiments discussed herein can also be practiced in other chambers, including those sold by other manufacturers. The large-area processing chamber is sized to process planar media, such as flat, flexible substrates having an area greater than about 15,000 square centimeters. In one embodiment, the substrate may have an area greater than about 50,000 square centimeters. In another embodiment, the substrate may have an area greater than about 55,000 square centimeters. In yet another embodiment, the substrate may have an area greater than about 60,000 square centimeters. In yet another embodiment, the substrate may have an area greater than about 90,000 square centimeters.

[0023] Figure 1 This is a schematic cross-sectional view of an apparatus 100 according to one embodiment. In the illustrated embodiment, apparatus 100 is a PECVD apparatus. Apparatus 100 includes a chamber body 102 into which a process gas from a gas source 104 is fed. When apparatus 100 is used for deposition, the process gas is fed from the gas source through a remote plasma source 106 and through a tube 108. In the remote plasma source 106, the process gas is not ignited into plasma. During cleaning, cleaning gas is sent from gas source 104 to the remote plasma source 106, where the cleaning gas is ignited into plasma, and then free radicals from the plasma enter the chamber. Tube 108 is a conductive tube 108.

[0024] An RF current used to excite the process gas into plasma within the chamber is coupled from an RF source 110 to a tube 108. Due to the skin effect of the RF current, it travels along the outside of the tube 108. The RF current will only penetrate a specific, predetermined depth into the conductive material. Therefore, the RF current travels along the outside of the tube 108, while the process gas travels inside the tube 108. As the process gas travels within the tube 108, it never sees the RF current because the RF current does not penetrate deep enough into the tube 108 to expose the process gas to the RF current within the tube 108.

[0025] Processing gas is fed into the chamber through the back plate 114. The processing gas then expands into the space 118 between the back plate 114 and the gas distribution plate or diffuser 116. The processing gas then travels through multiple gas passages 156 of the diffuser 16 and enters the processing space 148. Gas passages 156 are formed from the upstream side or back side 159 of the diffuser 116 to the downstream side or front side 160 of the diffuser 116.

[0026] On the other hand, the RF current does not enter the space 118 between the backplate 114 and the diffuser 116. Instead, the RF current travels along the outside of the tube 108 to the backplate 114. Then, the RF current travels along the atmospheric side 158 of the backplate 114. The backplate 114 comprises a conductive material. In one embodiment, the backplate 114 comprises aluminum. The RF current then travels from the backplate along a support 120 comprising a conductive material. In one embodiment, the support 120 comprises aluminum. The RF current then travels along the front side 160 of the diffuser 116, where it excites the process gas through the gas passage 156 into plasma located in the processing space 148 between the diffuser 116 and the substrate 124. The path of the RF current to reach the front side 160 of the diffuser 116 is indicated by arrow "A". An O-ring 122 electrically isolates the wall 146 from the backplate 114.

[0027] In one embodiment, diffuser 116 may include a conductive material. In another embodiment, diffuser 116 includes a metal. In yet another embodiment, diffuser 116 includes aluminum.

[0028] Materials such as silicon nitride (SiN) are deposited onto substrate 124 using plasma. Figure 1 In the illustrated embodiment, a substrate 124 is disposed on a base 126, which is movable between a first position spaced a first distance from the diffuser 116 and a second position spaced a second distance from the diffuser 116, wherein the second distance is smaller than the first distance. Figure 1 In the embodiment shown, the base 126 is mounted on the rod 136 and is movable by the actuator 140.

[0029] The substrate 124 is a large-area substrate, and therefore, it is flexible when the lifting rods 130 and 132 are raised. Thus, the lifting rods 130 and 132 can have different lengths. The base 126 can be in a lowered position when the substrate 124 is inserted into the chamber through the slit valve opening 144. When the base 126 is in the lowered position, the lifting rods 130 and 132 extend above the base 126. Therefore, the substrate 124 is first placed on the lifting rods. The lifting rods 130 and 132 have different lengths. The outer lifting rod 130 is longer than the inner lifting rod 132, causing the substrate 124 to be centrally sag when placed on the lifting rods 130 and 132. The base 126 is raised to meet the substrate 124. The substrate 124 contacts the base 126 during its center-to-edge travel, thereby expelling any gas present between the base 126 and the substrate 124. Then, the lifting rods 130 and 132, together with the base 124, are raised by the base 126.

[0030] When the base 126 is raised above the slit valve opening 144, the base 126 encounters the shadow frame 128. When not in use, the shadow frame 128 rests on the ledge 142 positioned above the slit valve opening 144. Due to its size, the shadow frame 128 may not be properly aligned. Therefore, rollers may be present on the shadow frame 128 or the base 126 to allow the shadow frame 128 to roll on the base 126 for proper alignment. The shadow frame 128 serves a dual purpose. The shadow frame 128 protects the area of ​​the base 126 not covered by the substrate 124 from the effects of deposition. Additionally, when the shadow frame 128 includes an electrically insulating material, it electrically shields the RF current traveling along the base 126 from the RF current traveling along the wall 146. In one embodiment, the shadow frame 128 includes an insulating material. In another embodiment, the shadow frame 128 includes a ceramic material. In yet another embodiment, the shadow frame 128 includes Al2O3. In another embodiment, the shadow frame comprises a metal, wherein an anodized layer is present on the metal. In one embodiment, the metal comprises aluminum. In another embodiment, the anodized layer comprises Al2O3.

[0031] The RF current needs to return to the power supply 110 that drives the RF current. The RF current is plasma-coupled to the base 126. In one embodiment, the base 126 comprises a conductive material such as aluminum. The RF current travels back to the power supply 110 via the path indicated by arrow 'B'. The RF current returns along wall 146 and backplate 112 before reaching the power supply 110.

[0032] To shorten the RF current return path, in one embodiment, one or more strips 134 are coupled to the base 126. Using the strips 134, the RF current travels down the strips 134 to the bottom 138 of the chamber and then returns to the inner wall 146 of the chamber. Without the strips 134, the RF current would travel down the bottom of the base 126, down the rod 136, and then return along the bottom 138 and inner wall 146 of the chamber. A high potential difference may exist between the RF current traveling down the bottom of the base 126 and the RF current on either the rod 136 or the bottom 138 of the chamber. Due to this potential difference, arcing may occur in the space 150 below the base. The strips 134 reduce the likelihood of arcing in the space 150.

[0033] In another embodiment, an anodized layer 170 is provided on a portion of the diffuser 116. In some embodiments, the base 126 not only has a strip 134 coupled to the base 126, but also has an RF return element 172 via an extension 174 coupled to the bottom of the base 126. The RF return element 172 is coupled to a protrusion 142 that supports the shadow frame 128 when the base 126 is in a lowered position. Figure 1 The illustrated RF return element 172 is a rod that provides an electrical connection between the base 126 and the protrusion 142. The return path provided by the RF return element 172 is shorter than that of the strip 134, and therefore, most of the RF current will return to the RF power source through the RF return element 172 rather than through the strip 134. Other RF return elements may also be used in conjunction with the anodized layer 170 and the strip 134, which will be discussed below. In one embodiment, the RF return element 172 may be disposed on and extend below the protrusion 142 until the extension 174 from the base 126 moves to contact the RF return element 172.

[0034] The anodized layer 170 can be used to tune the plasma within the processing space 148. As described in more detail below, the diffuser 116 includes a central region and an edge or peripheral region surrounding the central region. The phrase 'bare aluminum' is defined as an uncoated surface, excluding the natural or native oxide layer common to the aluminum surface. The anodized layer 170 can be defined as a layer or coating intentionally placed on a surface opposite a naturally occurring layer (such as a native oxide layer). The anodized layer 170 can be an oxide layer thicker than the naturally occurring oxide layer. The surface area of ​​the diffuser 116 covered by the anodized layer 170 can be determined based on a balance of two competing concerns: particle generation (affecting yield) and plasma homogeneity (affecting film homogeneity).

[0035] For example, the surface of a conventional diffuser is typically covered with an anodized film comprising porous microstructures. These microstructures tend to capture (i.e., adsorb) process gases and / or cleaning gases (or species of process gases and / or cleaning gases), which are then desorbed from the microstructures and adsorbed onto an electronic device on the substrate. In a specific example, nitrogen species from NH3 and / or N2O and fluorine species from NF3 can be absorbed into the microstructures and subsequently desorbed from them onto a silicon film formed on the substrate. It has been found that these desorbed species can cause a shift in the threshold voltage of the electronic device formed on the substrate. It has also been found that a large proportion of these species are absorbed on the back surface 159 of the diffuser 116 and then desorbed from there, affecting film and / or device formation. Each of the nitrogen species comprises one or more nitrogen atoms and optionally one or more other atoms, such as hydrogen, fluorine, and / or other elements. In one example, the nitrogen species can be NHx or NFx, where x is 0, 1, 2, or 3.

[0036] Therefore, it has been found that optimizing the surface morphology improves film purity, thereby minimizing or eliminating the shift in threshold voltage in devices formed on the substrate.

[0037] Figure 2 yes Figure 1 A cross-sectional view of a portion of the diffuser 116. The diffuser 116 includes a body 200, the body having a backplate 112 facing the backplate. Figure 1 The first side or upstream side 202 (as shown) (corresponding to) Figure 1 The diffuser 116 on the back side 159), and facing the base 126 ( Figure 1 The opposite second side or downstream side 204 (as shown) (corresponding to) Figure 1 The diffuser 116 has a front face 160. Each gas passage 156 is defined by a first orifice 210, which is coupled to a second orifice 212 via an orifice 214. This combination forms a fluid path through the diffuser 116. The first orifice 210 extends from the upstream side 202 of the diffuser 116 to a bottom or upper transition region 218. The upper transition region 218 of the first orifice 210 may be tapered, beveled, chamfered, or rounded to minimize fluid flow restriction as gas flows from the first orifice 210 into the orifice 214. The diameter of the first orifice 210 is typically from about 0.093 inches to about 0.218 inches, and in one embodiment is about 0.156 inches.

[0038] The thickness of diffuser 116 can be between about 0.8 inches and about 3.0 inches, for example, between about 0.8 inches and about 2.0 inches. A second aperture 212 is formed in diffuser 116 and extends from the downstream side (or end) 204 to a depth 232 of about 0.10 inches to about 2.0 inches. In one embodiment, the depth 232 can be between about 0.1 inches and about 1.0 inch. The diameter 236 of the second aperture 212 can typically be between about 0.1 inches and about 1.0 inch and can flare at an angle 216 of about 10 degrees to about 50 degrees relative to the downstream side 204. In one embodiment, the diameter 236 can be between about 0.1 inches and about 0.5 inches and the flare angle 216 can be between 20 degrees and about 40 degrees. The surface area of ​​the second aperture 212 can be about 0.05 inches. 2 approximately 10 inches 2 Between and in one implementation it can be about 0.05 inches 2 approximately 5 inches 2 The diameter of the second aperture 212 refers to the diameter intersecting with the downstream side 204. An example of a diffuser 116 for processing a 1500mm × 1850mm substrate has a second aperture 212 with a diameter of 0.250 inches and an opening angle 216 of approximately 22 degrees. The distance 280 between the edges 282 of adjacent second apertures 212 is between approximately 0.0 inches and approximately 0.6 inches, and in one embodiment, it may be between approximately 0.0 inches and approximately 0.4 inches. The diameter of the first aperture 210 is generally, but not limited to, at least equal to or smaller than the diameter of the second aperture 212. The bottom or lower transition region 220 of the second aperture 212 may be tapered, beveled, chamfered, or rounded to minimize pressure loss of gas flowing out of the orifice 214 and into the second aperture 212. Furthermore, since the orifice 214 is located near the downstream side 204 to minimize the exposed surface area of ​​the second orifice 212 and the downstream side 204 facing the substrate, the downstream area of ​​the diffuser 116 is exposed to fluorine supplied during chamber cleaning, thereby reducing the occurrence of fluorine contamination of the deposited film.

[0039] In one embodiment, the space of the second aperture 212 may include a hollow cathode cavity 250. For example, the aperture 214 generates back pressure on the upstream side 202 of the diffuser 116. Due to the back pressure, the process gas can be uniformly distributed on the upstream side 202 of the diffuser 116 before passing through the gas passage 156. The space of the hollow cathode cavity 250 allows plasma to be generated specifically within the gas passage 156 within the hollow cathode cavity 250. Variations in the space of the hollow cathode cavity 250, in contrast to the absence of a hollow cathode cavity, allow for better control of plasma distribution. At least a portion of the hollow cathode cavity 250 at the downstream side 204 may have a larger diameter 236 or width than the aperture 214. The width or diameter of the first aperture 210 is smaller than the plasma dark space, and therefore plasma does not form above the hollow cathode cavity 250.

[0040] Orifice 214 is typically coupled to the upper transition region 218 of the first orifice 210 and the lower transition region 220 of the second orifice 212. Orifice 214 may include a diameter of about 0.01 inches to about 0.3 inches (e.g., about 0.01 inches to about 0.1 inches) and a length 234 of about 0.02 inches to about 1.0 inch (e.g., about 0.02 inches to about 0.5 inches). Orifice 214 may be a throttling orifice, and the length 234 and diameter (or other geometric properties) of orifice 214 are primary sources of back pressure in the space between diffuser 116 and backplate 112 (e.g.,...). Figure 1 (As shown), this promotes uniform gas distribution on the upstream side 202 of the diffuser 116. The orifice 214 is typically configured to be uniformly distributed among the multiple gas passages 156; however, the orifice 214 can be configured differently among the gas passages 156 to promote more gas flow through one or more areas of the diffuser 116 relative to another area or region. For example, the orifice 214 may be closer to the wall 146 of the chamber 100 in those gas passages 156 of the diffuser 116. Figure 1 The diffuser 116 has a larger diameter and / or a shorter length 234, as shown, so that more gas flows over the edge of the diffuser 116 to increase the deposition rate in the peripheral area of ​​the substrate 105.

[0041] In one embodiment of this disclosure, the diffuser 116 includes an anodized layer 170 on the downstream side 204 and a portion of the gas passage 156, such as Figure 2As shown. In this embodiment, the anodized layer 170 is a conformal and / or uninterrupted layer covering the entire downstream side 204, the second aperture 212, the lower transition region 220, and the orifice 214. Conversely, the upper transition region 218, the first aperture 210, and the upstream side 202 of the diffuser 116 are bare (i.e., unanodized) metal, such as aluminum. Although only three gas passages 156 are shown, the other gas passages 156 through the diffuser 116 are identical.

[0042] Figure 3 This is a cross-sectional view of a portion of diffuser 116, showing a single gas passage 156, but the other gas passages 156 passing through diffuser 116 are identical. In this embodiment, diffuser 116 includes an anodized layer 170 on the downstream side 204 and throughout the gas passages 156. Specifically, the anodized layer 170 is a conformal and / or uninterrupted layer covering the entire downstream side 204, the second aperture 212, the lower transition region 220, the orifice 214, the upper transition region 218, and the first aperture 210. Conversely, the upstream side 202 of diffuser 116 is bare (i.e., unanodized) metal, such as aluminum.

[0043] Figure 4 This is a cross-sectional view of a portion of diffuser 116, showing a single gas passage 156, but the other gas passages 156 passing through diffuser 116 are identical. In this embodiment, diffuser 116 includes an anodized layer 170 on the downstream side 204 and a portion of the gas passage 156. Specifically, the anodized layer 170 is a conformal and / or uninterrupted layer covering the entire downstream side 204, the second aperture 212, and the lower transition region 220. Conversely, the orifice 214, the upper transition region 218, the first aperture 210, and the upstream side 202 of diffuser 116 are bare (i.e., unanodized) metal, such as aluminum.

[0044] Figure 5 This is a cross-sectional view of a portion of diffuser 116, showing a single gas passage 156, but the other gas passages 156 passing through diffuser 116 are identical. In this embodiment, diffuser 116 includes an anodized layer 170 on the downstream side 204 and a portion of the gas passages 156. Specifically, the anodized layer 170 is a conformal and / or uninterrupted layer covering the entire downstream side 204, the second aperture 212, the lower transition region 220, the orifice 214, the upper transition region 218, and a portion of the first aperture 210. Conversely, the remainder of the first aperture 210 and the upstream side 202 of diffuser 116 are bare (i.e., unanodized) metal, such as aluminum.

[0045] In some embodiments, the length 230 of the first aperture 210 (including the upper transition region 218) is approximately 1.0 inch to approximately 1.03 inches from the upstream side 202 of the diffuser 116. In this embodiment, the anodizing layer 170 covers approximately 50% of the surface of the first aperture 210 (e.g., having a length 230). For example, the terminating end 500 of the anodizing layer 170 includes a depth or length 505 of approximately 0.48 inches to approximately 0.53 inches, such as approximately 0.51 inches.

[0046] From a gas absorption perspective, a length of 505 greater than 50% may be more advantageous. However, the greater the depth of the 505 length, the more acidic the solution (below) becomes. Figure 6 The greater the likelihood that acid will flow into orifice 214 during the deanodicization process described herein and further downstream into the lower transition region 220 and / or the second orifice 212, the more likely it is to flow into the gas passage 156. Therefore, acid should be prevented from flowing into the gas passage 156 through the terminating end 500 of the anodized layer 170 to maintain... Figure 5 The anodized layer 170 is shown.

[0047] In some embodiments that can be combined with other embodiments described herein, the thickness of the anodized layer 170 is from about 1.8 micrometers (μm) to about 2.2 μm. In some embodiments that can be combined with other embodiments described herein, the average surface roughness (Ra) of the downstream side 204 (i.e., the anodized layer 170) is from about 1.9 μm to about 3.07 μm. In some embodiments that can be combined with other embodiments described herein, the Ra of the upstream side 202 of the diffuser 116 is from about 2.8 μm to about 3.1 μm.

[0048] Figure 6 This is a flowchart describing a method 600 for manufacturing a diffuser 116 as described herein. Method 600 includes block 605, where the diffuser 116 is machined. The machining includes forming a gas passage 156 as disclosed herein and may include further machining of the diffuser 116 for mounting in a chamber. Following the machining at 605, method 600 includes a heat treatment process in block 610. The heat treatment includes annealing and other heat treatments.

[0049] After heat treatment, perform the first cleaning process indicated in box 615. The first cleaning process includes one or a combination of stripping, intensive cleaning, and drying.

[0050] Following the cleaning process at 615, method 600 includes a roughening process at frame 620. The roughening process includes, but is not limited to, a bead blasting process. During the roughening process, all or part of the outer surface of diffuser 116 is roughened. In some embodiments, the orifice 214 is not roughened because its diameter may be too small.

[0051] Although not shown, optional polishing processes can be performed on some surfaces of diffuser 116. For example, the upstream side 202 of diffuser 116 can be polished to minimize surface roughness. Minimizing the surface roughness on portions of diffuser 116 reduces gas absorption, which minimizes the shift in threshold voltage in the device formed by diffuser 116. In one example, the upstream side 202 of diffuser 116 (and portions of the first aperture 210) can be polished to have an Ra of less than 1.5 μm.

[0052] A second cleaning process is performed after the roughening process, as shown in box 625. The second cleaning process includes one or a combination of peeling, intensive cleaning, and drying.

[0053] After the second cleaning, the diffuser 116 is anodized, as shown in box 630. During the anodizing process, all or part of the outer surface of the diffuser 116, including the gas passage 156, is roughened.

[0054] The third cleaning process indicated at box 635 is performed after the anodizing process. The third cleaning process includes one or a combination of stripping, intensive cleaning, and drying.

[0055] Following the third cleaning process, the diffuser 116, to which the anodic layer is disposed, is deanodized, as shown in box 640. The deanodization process involves immersing a portion of the diffuser 116 in an acid bath, which selectively removes the anodic layer. In one example, the diffuser 116 is suspended in the acid bath and lowered to a level in the acid solution where the anodic layer is desired to be removed.

[0056] Following the deanodic process, a fourth cleaning process is performed as indicated in box 645. The fourth cleaning process includes one or a combination of stripping, intensive cleaning, and drying. The fourth cleaning process may also include inspecting diffuser 116 and packaging diffuser 116 for shipment.

[0057] Figure 7This is a cross-sectional view of a portion of diffuser 116, showing a single gas passage 156, but the other gas passages 156 passing through diffuser 116 are identical. In this embodiment, diffuser 116 includes an anodized layer 170 on the downstream side 204 and a portion of the gas passages 156. Specifically, the anodized layer 170 is a conformal and / or uninterrupted layer covering the entire downstream side 204, the second orifice 212, the lower transition region 220, the orifice 214, the upper transition region 218, and a portion of the first orifice 210. The anodized layer 170 according to this embodiment is a first anodized layer.

[0058] In this embodiment, the remainder of the first aperture 210 and the upstream side 202 of the diffuser 116 include a second anodized layer 700. In this embodiment, which can be combined with several other embodiments described herein, the anodized layer 170 includes a plurality of pores 705 defining the first aperture porosity. The plurality of pores 705 include an average diameter of about 100 nanometers (nm). Conversely, the second anodized layer 700 includes a second aperture porosity greater than the first aperture porosity of the anodized layer 170. In one example, the second anodized layer 700 includes a plurality of pores 710, each pore including an average diameter greater than 100 nm. In a specific example, the pores 710 include an average diameter of about 110 nm to about 130 nm or greater. The transition from the first aperture porosity to the second aperture porosity is indicated by a transition line 715, which, according to this embodiment, is within the upper transition region 218. According to several other embodiments, the transition line may be within or above other portions of the gas passage 156. Differences in porosity can be controlled by changing the voltage applied during the anodizing process.

[0059] In some embodiments, the second anodized layer 700 may overlap with the anodized layer 170 at or near the transition line 715. In some embodiments, the transition line 715 may be located at the interface between the upper transition region 218 and the orifice 214. However, the length 234 of the orifice 214 represents a small fraction of the total thickness 720 of the diffuser 116. For example, the length 234 may be about 5% to about 9% of the total thickness 720, such as about 7%. Therefore, any overlap at the transition line 715 will not significantly affect the gas absorption of the diffuser 116, which has a significant impact on reducing the shift in the threshold voltage in the formed device.

[0060] The larger pore size of pore 710 relative to pore 705 helps reduce gas absorption in diffuser 116. For example, the size of pore 710 reduces gas absorption at upstream side 202 relative to gas absorption at downstream side 204. In some embodiments, the size of pore 710 is approximately twice the size of pore 705. In several other embodiments, the size of pore 710 is approximately twice the size of pore 705. In several other embodiments, the size of pore 710 is approximately 2.5 times the size of pore 705. It is contemplated that the larger pore size at upstream side 202 of diffuser 116 facilitates pumping out absorbed gas under vacuum conditions, which reduces threshold voltage shift.

[0061] Although several different embodiments of the diffuser 116 with an anodized layer 170 have been shown above, various embodiments can be combined across the diffuser 116. For example, some of the gas passages 156 can be constructed as shown (e.g., Figure 2 ), while others can be constructed as shown in other figures (e.g., Figures 3 to 5 (One or a combination of the anodized layers 170 shown). Furthermore... Figure 7 Another diffuser 116 is disclosed, which includes anodized layers on both sides. This embodiment can be compared with... Figures 2 to 5 Any other combination of implementations shown. Furthermore, changes can be made. Figure 6 The method 600 described herein is used to selectively remove an anodized layer on diffuser 116 and add another anodized layer, wherein the previous anodized layer was removed. In one example, diffuser 116 may first be anodized with a second anodized layer 700, and then a portion of the second anodized layer 700 may be removed where an anodized layer 170 is needed. Anodized layer 170 may then be applied to diffuser 116.

[0062] While the foregoing describes several embodiments of this disclosure, several other and further embodiments of this disclosure are conceivable without departing from the basic scope of this disclosure, and the scope of this disclosure is defined by the scope of the appended claims.

Claims

1. A gas distribution nozzle, comprising: The main body has a plurality of gas passages extending from an upstream side to a downstream side. Each of the plurality of gas passages includes an orifice, a first orifice portion between the upstream side and the orifice, an upper transition region between the first orifice portion and the orifice, a second orifice portion between the orifice and the downstream side, and a lower transition region between the second orifice portion and the orifice. A portion of the downstream side, the orifice of each of the plurality of gas passages, the second orifice, the upper transition region, the lower transition region, and the first orifice portion includes a first anodized layer disposed thereon as the outermost layer. The first anodized layer includes a first porosity. The remaining portion of the first orifice portion of each of the plurality of gas passages and the upstream side include a second anodized layer, the second anodized layer including a second porosity, wherein the second porosity is greater than the first porosity.

2. The gas distribution nozzle as claimed in claim 1, wherein both the first orifice and the second orifice surround the orifice.

3. The gas distribution nozzle of claim 1, wherein the first anodized layer comprises a material selected from the group consisting of Al2O3, SiO2, and combinations thereof.

4. The gas distribution nozzle of claim 3, wherein the first anodized layer has a thickness between 1 micrometer and 2 micrometers.

5. The gas distribution nozzle of claim 1, wherein the first anodized layer has a composition different from that of the second anodized layer.

6. A plasma processing apparatus, comprising: A processing chamber body, the processing chamber body having walls and a bottom plate; A base, which is disposed in the processing chamber body and is movable between a first position and a second position; and A nozzle, disposed opposite to the base within the main body of the processing chamber, the nozzle comprising: The body has multiple gas passages extending from an upstream side to a downstream side, the upstream side having a different porosity and roughness than the downstream side. Each of the multiple gas passages includes an orifice, a first pore portion between the upstream side and the orifice, an upper transition region between the first pore portion and the orifice, a second pore portion between the orifice and the downstream side, and a lower transition region between the second pore portion and the orifice. A portion of the downstream side, the orifice of each of the multiple gas passages, the second pore portion, the upper transition region, the lower transition region, and the first pore portion includes a first anodized layer disposed thereon as the outermost layer. The first anodized layer includes a first porosity. The remaining portion of the first pore portion of each of the multiple gas passages and the upstream side include a second anodized layer, the second anodized layer including a second porosity, wherein the second porosity is greater than the first porosity.

7. The device of claim 6, wherein both the first hole and the second hole surround the orifice.

8. A plasma-enhanced chemical vapor deposition apparatus, comprising: A chamber body, the chamber body having multiple walls and a chamber floor; A base is disposed in the chamber body and is movable between a first position spaced apart from the chamber floor by a first distance and a second position spaced apart from the chamber floor by a second distance greater than the first distance; Multiple strips, the multiple strips being coupled to the base and coupled to one or more of the chamber floor plate and the multiple walls, the multiple strips being unevenly distributed along the base; and A gas distribution nozzle, wherein the gas distribution nozzle is disposed within the chamber body opposite to the base, the gas distribution nozzle comprising: The body has multiple gas passages extending from an upstream side to a downstream side, the upstream side having a different porosity and roughness than the downstream side. Each of the multiple gas passages includes an orifice, a first pore portion between the upstream side and the orifice, an upper transition region between the first pore portion and the orifice, a second pore portion between the orifice and the downstream side, and a lower transition region between the second pore portion and the orifice. A portion of the downstream side, the orifice of each of the multiple gas passages, the second pore portion, the upper transition region, the lower transition region, and the first pore portion includes a first anodized layer disposed thereon as the outermost layer. The first anodized layer includes a first porosity. The remaining portion of the first pore portion of each of the multiple gas passages and the upstream side include a second anodized layer, the second anodized layer including a second porosity, wherein the second porosity is greater than the first porosity.

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