Gas flow inlet guide and process chamber comprising same

Abstract

The embodiments described herein provide a chamber having an airflow inlet guide for uniformly delivering a process gas. The airflow inlet guide has an open flow guide base plate. A top plate is disposed above the flow guide base plate, and a plasma blocker is disposed above the opening. The plasma blocker includes one or more pores, the size of which is determined based on one or more of the following: plasma density, electron temperature, ion temperature, or characteristics of the process gas.

Description

Technical Field

[0001] The embodiments disclosed herein generally relate to the design of airflow guides for processing chambers. More specifically, the embodiments disclosed herein relate to airflow guides for uniformly delivering processing gases and efficiently processing substrates with minimal defects. Prior Technology

[0002] Gas distribution components are used in many processing chambers, such as atomic layer deposition (ALD) chambers or plasma-enhanced CVD (PECVD) chambers, to provide uniform material deposition on a substrate. Parasitic plasma from a plasma source or from the processing volume of the processing chamber can infiltrate the gas distribution component and cause deposition therein. Over time, the deposited particles can contaminate the substrate or create defects within it.

[0003] Therefore, there is a need in the art for a chamber having a gas distribution assembly that uniformly delivers the processing gas and prevents parasitic plasma from seeping into it. Summary of the Invention

[0004] In one embodiment, an airflow inlet guide includes: a flow guide base plate including a first opening and a second opening, the second opening including a plasma blocker disposed thereon; a top plate disposed above and in contact with the flow guide base plate to define an air chamber; and a plurality of flow guides disposed within the air chamber to guide gas from the first opening to the second opening.

[0005] In another embodiment, an airflow inlet guide includes: a flow guide base plate including a first opening and a second opening, the second opening including a plasma blocker disposed thereon; a top plate disposed above and in contact with the flow guide base plate to define an air chamber; a flow guide regulator disposed within the air chamber between the first opening and the second opening; and a plurality of flow guides disposed within the air chamber to guide gas from the first opening to the second opening.

[0006] In another embodiment, a processing chamber includes: a chamber body; a cover coupled to the chamber body; and an airflow inlet guide coupled to the cover, the airflow inlet guide including: a flow guide base plate including a first opening and a second opening, the second opening including a plasma blocker disposed thereon, the flow guide base plate having a triangular shape; a top plate disposed above and in contact with the flow guide base plate to define an air chamber, the top plate having a triangular shape; a flow guide regulator disposed within the air chamber between the first opening and the second opening; and a plurality of flow guides disposed within the air chamber to guide gas from the first opening to the second opening. Simple Explanation of the Diagram

[0007] To gain a more detailed understanding of the features described above, reference can be made to the embodiments for a more specific description of the present disclosure, some of which are illustrated in the accompanying drawings. However, it should be noted that the drawings illustrate only exemplary embodiments and should not be considered as limiting the scope of the disclosure, as other equally effective embodiments are permissible.

[0008] Figure 1 is a schematic cross-sectional view of an atomic layer deposition chamber according to one embodiment.

[0009] Figure 2 is a schematic cross-sectional side view of an airflow inlet guide according to an embodiment.

[0010] Figure 3A is a schematic diagram of the flow guide base plate of an airflow inlet guide according to an embodiment.

[0011] Figure 3B is a schematic diagram of a flow regulator according to one embodiment.

[0012] Figure 4 is a schematic bottom view of the top plate of the flow guide of an airflow inlet guide according to an embodiment.

[0013] Figure 5 depicts an exemplary Debye length curve for determining the mesh size of a plasma blocker according to one embodiment.

[0014] To facilitate understanding, the same reference numerals are used to denote common elements in the drawings, where possible. Elements and features of one embodiment are contemplated to be advantageously incorporated into other embodiments without further description. Implementation

[0015] The embodiments described herein provide a chamber having an inlet airflow guide for uniformly delivering a processed gas and an outlet airflow guide for effectively purifying the processed gas and shortening the purification time. The chamber includes a chamber body with a cover assembly, a processed gas inlet and a processed gas outlet configured in fluid communication with a processing area within the chamber, an inlet airflow guide disposed in the processed gas inlet, and an outlet airflow guide disposed in the processed gas outlet. The inlet airflow guide includes a flow regulator and an inlet guiding channel. The outlet airflow guide includes an outlet guiding channel.

[0016] Figure 1 is a schematic cross-sectional view of an ALD chamber 100 according to one embodiment. Suitable ALD chambers are available from Applied Materials, Inc., located in Santa Clara, California. It should be understood that the system described below is an exemplary chamber, and other chambers, including those from other manufacturers, can be used with or modified to implement the various embodiments of this disclosure. PECVD chambers are also expected to benefit from the various embodiments of this disclosure. The ALD chamber 100 includes a chamber body 102, a cover assembly 104, a process kit 106, a substrate support assembly 108, a process gas inlet 110, and a process gas outlet 112.

[0017] A cover assembly 104 is disposed above the chamber body 102, and a substrate support assembly 108 is at least partially disposed within the chamber body 102. A process kit 106 is coupled to the cover assembly 104. The substrate support assembly 108 includes a base 116 movably disposed within the chamber body 102 by means of a rod 118. The base 116 includes a substrate support surface 132 configured to support a substrate 101. The rod 118 extends through the chamber body 102, where it is connected to a lifting system (not shown) that moves the base 116 between a processing position (as shown) and a transfer position. The transfer position facilitates the transfer of the substrate 101 via a slit valve opening 114 formed in the sidewall of the chamber body 102 to provide access to the interior of the ALD chamber 100.

[0018] In the processing position, the substrate support assembly 108 contacts the process kit 106 to form a processing region 120 defined by the substrate support surface 132, the process kit 106, and the lower surface of the cover assembly 104. When the substrate support assembly 108 in the processing position contacts the process kit 106 to form the processing region 120, the gas inlet 122 and gas outlet 124 of the process kit 106 are coupled to the processing gas inlet 110 and processing gas outlet 112, respectively, to form sealed corresponding gas channels. The processing gas inlet 110 and processing gas outlet 112 are positioned in fluid communication with the processing region 120. In this manner, processing gas is provided to the processing gas inlet 110 and the processing region 120 via the gas inlet 122. The processing gas outlet 112 is connected to the pump 126. The processing gas flows through the substrate 101 in the processing region 120 and is discharged by the pump 126 via the gas outlet 124 and processing gas outlet 112. An RF (radio frequency) source 128 is coupled to an electrode 130 of the cover assembly 104. The RF source 128 supplies power to the electrode 130 to facilitate the generation of plasma from the process gas in the processing region 120. The base 116 is grounded, or, when connected to the RF source 128, can be used as a cathode to generate a capacitive electric field between the lower surface of the cover assembly 104 and the base 116, thereby accelerating the plasma material toward the substrate 101.

[0019] One or more specific gases used for ALD and / or PECVD depend on one or more processes to be performed. In one embodiment, the gas may include trimethylaluminum (CH3)3Al (TMA), CpZr, tetraethylmethylaminozirconium Zr[N(CH3)(C2H5)]4 (TEMAZ), nitrogen (N2), and oxygen (O2). However, the gas is not limited to these and may include one or more precursors, reducing agents, catalysts, supports, purifying gases, cleaning gases (e.g., BCl3), or any mixture or combination thereof. The gas is introduced into the ALD chamber 100 from one side and flows over the substrate 101. For example, the gas flows through the process gas inlet 110, the gas inlet 122 and through the processing area 120, and is discharged via the gas outlet 124 and the process gas outlet 112.

[0020] In an exemplary alumina (Al₂O₃) film formation process, a TMA stream is delivered to processing region 120. The TMA flowing through processing region 120 flows over substrate 101 and forms a TMA layer on substrate 101. An oxygen-containing gas stream is delivered to processing region 120. The oxygen-containing gas flowing through processing region 120 flows over substrate 101 and is activated into plasma to provide oxygen free radicals for reaction with the TMA layer. In one embodiment, the oxygen-containing gas is O₂ or ozone (O₃). The oxygen free radicals react with the TMA layer on substrate 101 to form an Al₂O₃ layer. The process of flowing TMA, flowing oxygen-containing gas, and activating oxygen-containing gas into plasma to form an additional layer on substrate 101 is repeated until an Al₂O₃ film of desired thickness is formed.

[0021] In an exemplary zirconium dioxide (ZrO₂) film formation process, a TEMAZ stream is conveyed to processing region 120. The TEMAZ flowing through processing region 120 flows over substrate 101 and forms a TEMAZ layer on substrate 101. An oxygen-containing gas stream is conveyed to processing region 120. The oxygen-containing gas flowing through processing region 120 flows over substrate 101 and is activated into plasma to provide oxygen free radicals for reaction with the TEMAZ layer. The oxygen free radicals react with the TEMAZ layer on substrate 101, thereby forming a ZrO₂ layer on substrate 101. The processes of conveying TEMAZ, conveying O₂, and activating oxygen-containing gas into plasma are repeated until a ZrO₂ film of the desired thickness is formed.

[0022] An airflow inlet guide 202 is provided for uniformly delivering the process airflow, and an airflow outlet guide 203 is provided for effectively and efficiently purifying the process gas. During processing, parasitic plasma (such as plasma from a plasma source (not shown) or from the process volume) infiltrates conventional airflow inlet guides and causes deposition within the flow guide assembly. This deposition results in particle generation, which leads to contamination on the substrate (such as a glass substrate disposed on a substrate support). However, it has been found that plasma infiltration into the airflow inlet guide 202 can be significantly reduced by including a plasma blocker 201 at the interface between the opening of the airflow inlet guide 202 and the process kit 106. The plasma blocker 201 may comprise, for example, a mesh material or grid formed of metal, and allow airflow to pass through it while preventing the infiltration of parasitic plasma. Parasitic plasma infiltration can be prevented by selecting a mesh material of appropriate size.

[0023] Figure 2 is a schematic cross-sectional side view of the airflow inlet guide 202. The airflow inlet guide 202 is formed by a flow guide top plate 204 coupled to a flow guide base plate 206. The airflow inlet guide 202 includes a process gas inlet 110 formed therein. The flow guide top plate 204 forms an hermetically sealed seal with the flow guide base plate 206, such as with a top plate seal 210 (e.g., an O-ring), to define the process gas inlet 110. At least one (multiple are illustrated in Figure 3) channel 214 is provided within the process gas inlet 110. Each channel 214 is defined between adjacent guides 270, wherein the flow guides are arranged in a non-parallel configuration relative to each other. The channel 214 facilitates improved airflow through the process gas inlet 110. Process gas is supplied to the process gas inlet 110 via inlet 274. The optional flow guide regulator 390 (described in further detail with reference to Figure 3B) facilitates the guidance and / or regulation of airflow in channel 214.

[0024] The flow guide base plate 206 includes an opening 208 in fluid communication with the processing region 120 (as shown in Figure 1). The opening 208 is aligned with an opening in the process kit 106 to facilitate fluid communication with the processing region 120. The flow guide base plate 206 forms a hermetically sealed connection with the process kit 106, such as a hermetically sealed connection with a flow guide body seal 212 (e.g., an O-ring). In some embodiments, the process kit 106 is made of ceramic (such as quartz, silicon carbide, silicon nitride) or another ceramic material.

[0025] Process gas from process gas source 272 flows through process gas inlet 110, through at least one channel 214, and reaches opening 208. Plasma blocker 201 is disposed at interface 207 between process kit 106 and flow guide base plate 206. Plasma blocker 201 is coupled to flow guide base plate 206 or process kit 106. Alternatively, flow guide base plate 206 is clamped between process kit 106 and flow guide base plate 206 in a recess provided by flow guide body seal 212. Plasma blocker is a mesh material, such as a metal mesh, that allows gas to pass through while preventing parasitic plasma backflow. In one example, the mesh size is selected to mitigate plasma backflow. Various mesh configurations, including sizes and patterns, are envisioned to facilitate sufficient airflow while mitigating parasitic plasma backflow. For example, the mesh may be formed from a plurality of metal wires positioned to form square or rectangular openings. In such instances, the width or length of such openings can be 750 micrometers or less, such as 500 micrometers or less, such as 400 micrometers or less, such as 300 micrometers or less, such as 200 micrometers or less, 150 micrometers or less, such as 100 micrometers or less, such as 50 micrometers or less, such as 40 micrometers or less, such as 30 micrometers or less, such as 20 micrometers or less. Other sizes may also be considered, as mentioned above.

[0026] Figure 3A is a schematic top view of the flow guide base plate 206, and Figure 4 is a schematic bottom view of the flow guide top plate 204. The flow guide base plate 206 includes an interface surface configured to at least partially interface with the process kit 106. This interface surface is the main surface opposite the inner surface 302. A seal 212 (shown in dashed lines) is disposed in this interface surface. Although the flow guide base plate 206 is depicted as a triangle with two sides of equal length, other shapes, including triangles of other shapes, are also conceivable.

[0027] The flow guide base plate 206 includes an upstream end 306 and a downstream end 307. An opening 208 is disposed adjacent to the downstream end 307 and configured to dispense gas through the opening. A plasma blocker 201 is at least partially disposed above the opening 208. As shown, the plasma blocker 201 completely covers the opening 208. The plasma blocker 201 is removably coupled to the flow guide base plate 206 or clamped between the process kit 106 and the flow guide base plate 206. A recess may be formed in the process kit 106 or the flow guide base plate 206 to accommodate the plasma blocker 201 therein. In some embodiments, the plasma blocker 201 is replaced after a predetermined number of substrate treatments. In some embodiments, the plasma blocker 201 is cleaned using a cleaning chemical compatible with the material of the plasma blocker 201 (such as BCl3). In some embodiments, the plasma blocker 201 is replaced after a predetermined number of treatments. In some embodiments, plasma blocker 201 and seal 212 are replaced during maintenance.

[0028] A plurality of channels 214 are formed between adjacent guides 270. The guides 270 are angularly spaced from each other and guide the gas toward the plasma blocker 201. The guides 270 extend from the optional airflow regulator 390 to a predetermined distance. It is conceivable that the guides 270 may extend to the plasma blocker 201, or may extend to a shorter position of the plasma blocker (as shown). It is further conceivable that the length, width, angular spacing, and number of the guides 270 can be adjusted to affect the airflow according to process specifications.

[0029] In one instance, the length of the plasma blocker is at least twice its width, such as at least 5 times, at least 10 times, or at least 20 times. In one instance, the length of the plasma blocker 201 is greater than the maximum width of the widest point of the outermost flow guide 270. Other sizes and configurations are also possible.

[0030] Figure 3B is a schematic diagram of an optional airflow regulator 390. The airflow regulator 390 can be coupled to the flow guide base plate 206 to facilitate airflow guidance within the airflow inlet guide 202. The airflow regulator includes a plurality of openings 291 (labeled as one) for guiding gas into a channel 214. In one example, each opening 291 corresponds to a single channel 214, but other configurations are also considered. The size (e.g., diameter), orientation, position, and / or number of openings can be adjusted to guide flow through the channel 214 in a predetermined manner, thereby adjusting process uniformity (e.g., deposition uniformity). The airflow regulator 390 is arcuate in shape (but other shapes are also contemplated). The ends of the airflow regulator 390 abut adjacent sidewalls of the flow guide base plate 206.

[0031] Referring to Figure 4, a bottom view of the flow guide top plate 204 is illustrated as having a recessed portion 404 surrounding a surface 408. The recessed portion 404 is a groove configured to support a seal therein. For example, the recessed portion 404 could be a dovetail groove for the top plate seal 210 (as shown in Figure 2). The surface 408 is configured to at least partially interface with the flow guide base plate 206 to define a gas chamber (e.g., process gas inlet 110) within the flow guide base plate.

[0032] The flow guide top plate 204 is coupled to the flow guide bottom plate 206 using fasteners 406 (three are shown, but more are contemplated). Although the flow guide top plate 204 is depicted as triangular, other shapes are also possible. Furthermore, although the recessed portion 404 is depicted as triangular, other shapes are also possible, such as triangles with one or more rounded vertices. Apart from the presence of the recessed portion 404, the flow guide top plate 204 is a flat component with flat opposing main surfaces.

[0033] It has been found that plasma blocker 201 (as shown in Figure 1) inhibits material deposition on surfaces, such as surface 408, of the volume forming the gas flow inlet guide 202. Plasma blocker 201 is made of a metal, such as stainless steel, aluminum, nickel, alloys thereof, or combinations thereof. Plasma blocker 201 is a mesh having a aperture size determined based on the Debye length (λD) of one or more plasmas used in the process. The plasma blocker includes one or more apertures, the size of which is based on one or more plasma properties, such as plasma density, electron temperature, or ion temperature. In some embodiments, the aperture size is based on properties of the processed gas, such as the size of gas atoms or gas molecules. As used herein, aperture size refers to the length or diameter of the pores in the mesh, such as the average length or diameter. The mesh can consist of a first set of wires arranged in a flat surface and a second set of wires arranged on top of the first set. Each adjacent wire in the first set is substantially parallel to each other, and each adjacent wire in the second set is also substantially parallel to each other. The first set of wires is offset at an angle relative to the second set, such as in a perpendicular arrangement. The mesh openings can be the distance between adjacent wires in the first or second set, or the distance between the intersections of adjacent wires. Other mesh textures and arrangements are also possible.

[0034] The length of the Debye is determined using the following equation (1). Equation (1) Where λD is the Debye length, ε0 is the dielectric constant of the material (e.g., in free space), kB is the Boltzmann constant, qe is the electron charge, Te is the electron temperature, Ti is the ion temperature, ne is the electron density, and nj is the density of atomic matter j, where the positive ion charge is zjqe.

[0035] In some embodiments, such as when ion mobility is negligible, the Debye length is determined using the following equation (2). Equation (2) Where λD is the Debye length, ε is the dielectric constant of the material (e.g., free space), kB is the Boltzmann constant, q is the electron charge, Te is the electron temperature, and n is the electron density.

[0036] The mesh size can be a factor of the Debye length, which can be expressed by the following equation (3). Mesh size = C × λD, where C is greater than 0. Equation (3)

[0037] A C value of about 0 to about 1 or less corresponds to very good shielding; however, it may at least partially or completely block the process gas flow and plasma. In some embodiments, a C value of about 1 or greater, such as about 1 to about 10, such as about 2 to about 5, provides good plasma shielding while allowing the process gas to flow through.

[0038] Figure 5 depicts a curve generated by the CCP parameters, which correlates various plasma densities with the corresponding Debye length used to determine the aperture size. For the exemplary process, the plasma electron density is from about 1 × 10¹⁰ cm³ to about 10 × 10¹⁰ cm³, and the electron temperature is from about 1 eV to about 4 eV. The plasma electron density can be from about 3 × 10¹⁰ cm³ to about 5 × 10¹⁰ cm³, or from 7 × 10¹⁰ cm³ to about 9 × 10¹⁰ cm³. The aperture size is chosen from about 50 μm to about 100 μm. The aperture size is chosen to prevent plasma infiltration under high-probability conditions, while allowing process gases to pass through the mesh and enter the process volume. Depending on the plasma, other electron densities and aperture sizes may also be considered. It has been found that choosing too small an aperture size can affect the process. For example, choosing a mesh size that is too small can alter the chemical properties of the gas flowing into the processing chamber by blocking at least some of the gas molecules required for the process. Furthermore, choosing a mesh size that is too large is ineffective in reducing parasitic plasma entering the airflow inlet guide 202.

[0039] Although plasma blocker 201 is described with reference to an ALD chamber, other plasma chambers, such as PECVD chambers, may also be considered. Plasma blocker 201, formed by a mesh, can be used to allow gas to flow through while blocking parasitic plasma by sizing the mesh size based on plasma process characteristics such as plasma density and electron temperature.

[0040] Although the examples given above are related to this disclosure, other and further examples of this disclosure may be designed without departing from the basic scope of this disclosure, and the scope of this disclosure is determined by the appended claims.

[0041] 100: ALD chamber 101:Substrate 102: Main body of the chamber 104: Cover assembly 106: Process Kit 108: Substrate support assembly 110: Processing gas inlet 112: Processing gas outlet 114: Slit valve opening 116: Base 118: pole 120: Processing Area 122: Gas Inlet 124: Gas outlet 126: Pump 128: RF source 130: Electrode 132: Substrate support surface 201: Plasma Blocker 202: Airflow Inlet Guide 203: Airflow outlet guide 204: Flow Guide Top Plate 206: Flow Guide Base Plate 207: Interface 208: Opening 210: Top plate seal 212: Flow guide body seal 214: Channel 270: Bootloader 272: Processing gas sources 274: Entrance 302: Inner surface 306: Upstream end 307: Downstream end 390: Airflow regulator 404: Depressed area 406: Fasteners 408: Surface

[0042] Domestic storage information (please note in order of storage institution, date, and number) none Overseas storage information (please note in the order of storage country, institution, date, and number) none

Claims

1. An airflow inlet guide, comprising: A flow guide base plate including a first opening and a second opening, the second opening including a plasma blocker disposed thereon, wherein the plasma blocker is a metal mesh with a pore size of about 50 μm to about 100 μm; a top plate disposed above and in contact with the flow guide base plate to define a gas chamber; and a plurality of flow guides disposed in the gas chamber to guide gas from the first opening to the second opening.

2. The airflow inlet guide as claimed in claim 1, wherein the metal mesh comprises stainless steel, aluminum, nickel, alloys thereof, or combinations thereof.

3. The airflow inlet guide as described in claim 1, wherein the metal mesh comprises stainless steel.

4. The airflow inlet guide as described in claim 1, wherein the metal mesh comprises aluminum.

5. The airflow inlet guide as claimed in claim 1, wherein the plasma blocker is disposed in a groove formed in a surface of the base plate of the airflow guide.

6. An airflow inlet guide, comprising: A flow guide base plate including a first opening and a second opening, the second opening including a plasma blocker disposed thereon, wherein the plasma blocker is a metal mesh with a pore size of about 50 μm to about 100 μm; a top plate disposed above and in contact with the flow guide base plate to define a gas chamber; a flow guide regulator disposed within the gas chamber between the first opening and the second opening; and a plurality of flow guides disposed within the gas chamber to guide gas from the first opening to the second opening.

7. The airflow inlet guide as claimed in claim 6, wherein the metal mesh comprises stainless steel, aluminum, nickel, alloys thereof, or combinations thereof.

8. The airflow inlet guide as claimed in claim 7, wherein the flow guide regulator includes a plurality of openings formed therethrough, and each opening is aligned with a channel defined by an adjacent flow guide.

9. The airflow inlet guide as described in claim 8, wherein the airflow guides are not parallel to each other.

10. The airflow inlet guide as claimed in claim 9, wherein each of the respective airflow guides has a length, and the length of the laterally outward airflow guide is greater than the length of the inwardly positioned airflow guide.

11. A processing chamber, comprising: One main chamber; A cover, which is coupled to the main body of the chamber; The device also includes an airflow inlet guide coupled to the cover, the airflow inlet guide comprising: a flow guide base plate including a first opening and a second opening, the second opening including a plasma blocker disposed thereon, wherein the plasma blocker is a metal mesh with a pore size of about 50 μm to about 100 μm, the flow guide base plate having a triangular shape; a top plate disposed above and in contact with the flow guide base plate to define an air chamber, the top plate having a triangular shape; a flow guide regulator disposed within the air chamber between the first opening and the second opening; and a plurality of flow guides disposed within the air chamber to guide gas from the first opening to the second opening.

12. The processing chamber as described in claim 11 is further processed with a process kit that engages the flow guide base plate.

13. The processing chamber as claimed in claim 11, wherein the metal mesh comprises stainless steel, aluminum, nickel, alloys thereof, or combinations thereof.

14. The processing chamber as claimed in claim 13, wherein the flow guide regulator includes a plurality of openings formed therethrough, and each opening is aligned with a channel defined by an adjacent flow guide.

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