Patent Application
20220098729
Embodiments of the present disclosure generally relate to systems and methods of manufacturing a semiconductor device. More particularly, the present disclosure is directed to systems and methods of cleaning process chambers using plasma.
Plasma enhanced chemical vapor deposition (PECVD) are processes used to deposit a film on a substrate, such as a semiconductor substrate. PECVD is accomplished by introducing process gasses into a process chamber that contains the substrate. The process gasses are directed through a gas distribution assembly and into a process volume in the process chamber.
Electromagnetic energy, such as from radio frequency (RF) power is used to activate the process gasses in the process chamber to generate plasma. The plasma is used to for a variety of processes including etching, thin film deposition in semiconductor substrates, and chamber cleaning. Plasma processes vary greatly and depend on temperature, pressure, type of gas, gas flow rate, and other process conditions. Moreover, plasma cleaning varies in efficiency, effectiveness, and damage to chamber components.
Therefore, there is a need for an efficient, effective chamber clean method and system with minimal damage to chamber components.
In one embodiment, a method is provided including introducing a gas mixture to a remote plasma source, the gas mixture includes argon, oxygen and nitrogen gas. The argon gas to oxygen gas ratio in the gas mixture is about 0.2:1 to about 1:1 by volume. A plasma is formed from the gas mixture in the remote plasma source. The plasma includes oxygen radicals, argon radicals, and nitrogen radicals. The plasma is introduced to a process volume of the process chamber and exposes surfaces of one or more chamber components. The process volume of the chamber has a pressure of about 10 mTorr to about 6 Torr and a temperature above 300° C.
In another embodiment, a method is provided, including introducing a gas mixture having argon gas, nitrogen gas, and oxygen gas to a remote plasma source. The gas mixture has a nitrogen gas to oxygen gas ratio of between about 1:1000 to about 1:5 by volume. The gas mixture is energized in the remote plasma source to form a plasma. The plasma is composed of oxygen radicals, argon radicals, and nitrogen radicals. The plasma is introduced to a process volume of the process chamber. The process chamber includes a chamber body and a lid defining a volume of the process chamber. A substrate support disposed in the volume of the process chamber, and a faceplate is disposed between the substrate support and the lid. A blocker plate or a flange is disposed between the faceplate and the lid. The blocker plate includes perforations dispose throughout the surface of the blocker platen and the perforations have a uniform diameter of about 0.1 mm to about 2 mm. The method includes exposing the faceplate within the process volume to the plasma.
In another embodiment, a method is provided including coating a portion of a chamber component. The coating is selected from the group consisting of a metal oxide, a metal nitride, a silicon containing composition, and combination(s) thereof. The chamber component is processed using processing conditions during substrate processing. Contaminants are formed on the chamber component. The chamber component is exposed to a cleaning plasma including oxygen radicals, argon radicals, and nitrogen radicals. The plasma is formed from a gas mixture having an argon gas to oxygen gas ratio of about 0.2:1 to about 1:1 by volume and a nitrogen gas to oxygen gas ratio of between about 1:1000 to about 1:5 by volume.
So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only example embodiments of this disclosure and are therefore not to be considered limiting of its scope, for the disclosure may admit to other equally effective embodiments.
To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.
Embodiments presented herein are directed to plasma cleaning in process chambers. The plasma cleaning described herein is useful to efficiently clean contaminants such as carbon based contaminants from chamber components, such as faceplates.
Methods of cleaning process chamber components is provided herein including forming a plasma composed of oxygen radicals, argon radicals, and nitrogen radicals. The plasma is formed in a remote plasma source and is introduced to a process volume of the process chamber and exposes one or more chamber components disposed therein for cleaning.
The process chamber includes a blocker plate or a flange, and a faceplate disposed between a lid and a substrate support of the chamber. The blocker plate and faceplate are designed to manage plasma flow distribution into a process volume of the process chamber.
The faceplate 118 is coupled to a portion of the lid assembly 110 and is coupled to a power supply (not shown), such as radiofrequency (RF) power for facilitating plasma generation within the processing chamber 100A. A gas feedthrough 134 is disposed in the lid 110 and is coupled to the remote plasma source 105, such that process gases are introduced to the process volume 112 by passing through the feedthrough 134 and faceplate 118. During chamber cleaning processes, cleaning gases are supplied from one or more gas sources (e.g., 104) to the remote plasma source 105, and distributed by the faceplate 118. In some embodiments, which can be combined with other embodiments described herein, the faceplate 118 is designed to distribute gas into the process volume 112 with a predetermined gas distribution profile.
A substrate support assembly 138 is disposed below the faceplate 118. A substrate is positionable on the substrate support assembly 138 through a port 126 in the sidewalls 106. During processing, a substrate is secured to the substrate support assembly 138 by vacuum or by electrostatic chuck. The temperature of the substrate is increased to a process temperature by heating the substrate support assembly 138 with a heater (not shown).
A flange 135 is removably coupled to the process chamber between the lid 110 and the faceplate 118, as shown in
The blocker plate 136 is positioned and configured to enhance the uniform distribution of gases passing through the faceplate 118 and into the chamber volume 112. In both arrangements described in
In one example, a central hole density of the central region 202 is the same as an edge hole density of the edge region 204, or the central hole density of the central region 202 is greater than the edge hole density of the edge region 204, or the central hole density of the central region 202 is less than the edge hole density of the edge region 204. For example, the central hole density of the central region 202 is greater than the edge hole density of the edge region 204 to increase the gas flow through the central region 202 relative to the edge region 204. In some embodiments, which can be combined with other embodiments described herein, the edge hole density is about 20% to about 60% lower than the central hole density. The edge hole density is uniform throughout the edge region 204, or the edge hole density is reduced radially outward from the center of the faceplate 118.
The central region 202 is sized based on the size of a substrate processed within the process volume. For example, the central region 202 may be about 200 millimeters (mm) to about 450 mm in diameter, such as about 200 mm, 300 mm, 320 mm or 450 mm in diameter. Other diameters are also contemplated. The edge region 204 has an outer edge diameter about 5% to about 25% larger than the diameter of the central region 202. The faceplate 118 described herein, has a faceplate design that distributes radical flux uniformly through the faceplate 118 to the process volume. The faceplate design includes geometry of the perforation holes (e.g., large hole size) and hole density (e.g., high hole density) over the different regions of the faceplate 118. The faceplate design includes holes arranged in a concentric pattern.
The blocker plate 136 described herein distributes radical flux uniformly through the blocker plate 136 to the process volume 112. The geometry of the perforation holes (e.g., hole size) and hole density over the different regions of the blocker plate 136 facilitates the increased radical flux uniformity. The blocker plate 136 and the faceplate 118, or the flange 135 and faceplate 118, have high radical conductance and high etch efficiency in the chamber volume 112. In some embodiments, which can be combined with other embodiments described herein, each hole diameter is about 0.1 mm to about 3 mm, such as about 0.3 mm to about 2 mm. In some embodiments, which can be combined with other embodiments described herein, a hole spacing, defined by the distance from a center of a first hole and a center of a second adjacent hole, is about 2 mm to about 15 mm for the blocker plate 136.
At least one of the chamber components is coated with a film having a film thickness of about 100 nm to about 3 um and an average surface roughness of less than Ra 64, such as less than Ra 20, as determined by atomic force microscopy. The one or more chamber components are coated by physical vapor deposition (PVD), atom layer deposition (ALD), plasma spray, and electron beam and ion beam assisted deposition (EB-IAD), chemical vapor deposition (CVD), or any other method of deposition capable of depositing the coating. In some embodiments, which can be combined with other embodiments described herein, the coating is aluminum oxide deposited by ALD, yttrium oxide (e.g., yttria) deposited by ALD, yttrium doped with silicon oxide deposited by ALD, aluminum oxide doped with silicon oxide deposited by ALD, yttrium oxyfluoride (e.g., YOF) deposited by ALD, hafnium oxide (HfO2) deposited by ALD, aluminum oxide deposited by EB-IAD, yttrium oxide zirconium oxide (e.g., Y2O3-ZrO2) deposited by EB-IAD, yttrium aluminum garnet (YAG) deposited by EB-IAD, and combination(s) thereof. The coating is deposited over the chamber component ex situ, for example using ALD and/or by EB-IAD. Alternatively or additionally, the coating is deposited in situ, and may include silicon oxide, silicon nitride, silicon carbide, silicon carbon nitride (SiCN), carbon, deposited by CVD. Any high quality coating composition can be used and deposited by any method and any coating described herein can be doped with silicon oxide (SiOx). A high quality coating refers to a film having uniform stoichiometry of composition molecules, high purity, high density, no (or minimal) hydroxides or carbon hydroxide groups. In some embodiments, which can be combined with other embodiments described herein, the coating process is performed in the same chamber as the cleaning process. In such an example, the coating process may be a seasoning process. In some embodiments, which can be combined with other embodiments described herein, the coating process is performed in a different chamber as the cleaning process.
The coating deposited thereon has an average surface roughness value less than 16 Ra, as determined by atomic force microscopy (AFM). It is believed that having a low average surface roughness reduces surface recombination of radicals upon exposure to radicals. The coated chamber component enables better etch rate when compared to uncoated chamber components. Moreover, coated chamber components are less susceptible to damage from the process chemistry than uncoated chamber components.
Referring back to
In operation 406, the one or more chamber components having amorphous carbon, and/or semiconductor contaminants are exposed to a cleaning plasma, within a process chamber. In some embodiments, which can be combined with other embodiments described herein, the process chamber of operation 406 is the same chamber as chambers of operation 402 and/or operation 404. The cleaning plasma includes oxygen radicals, argon radicals, and nitrogen radicals. Oxygen-radical-containing plasma is effective for cleaning contaminants such as amorphous carbon. The plasma is formed by providing oxygen-containing gas from a gas source 104 to the remote plasma source 105. The oxygen-containing gas, such as oxygen gas (O2) is introduced to the remote plasma source 105 to form neutral radical species in the remote plasma source 105. Additionally, one or more of nitrogen-containing gas and argon gas are also provided to the remote plasma source, and generated neutral and active radical species. The nitrogen-containing gas includes one or more of N2, N2O, NO, and combinations thereof. Although
The gas mixture is energized in the remote plasma source 105 using an excitation source to form a plasma. In some embodiments, which can be combined with other embodiments described herein, the excitation source is radiofrequency, microwave, or combinations thereof. The gas mixture is energized at a power of about 7000 W to about 10000 W, such as about 8000 W to about 9000 W.
During excitation, each of the gas components of the gas mixture are dissociated to radicals in the remote plasma source 105 to form a plasma. One or more chamber components are exposed to the plasma for about 80 seconds to about 600 seconds, such as about 100 seconds to about 400 seconds, such as about 100 seconds to about 200 seconds for cleaning. The plasma flow rate is about 10,000 sccm to about 32,000 sccm, such as about 15,000 sccm to about 25,000 sccm. The oxygen radicals facilitate effective cleaning of process chamber components when the oxygen radicals are present in a high oxygen radical density. In some embodiments, which can be combined with other embodiments described herein, the percentage of oxygen gas converted to oxygen radicals is about 20 to about 30 percent. The percentage is characterized by the number of molecules per unit of volume. Without being bound by theory, it is believed that argon radicals combined with oxygen containing gas promotes oxygen dissociation and oxygen radical generation. Another consideration is that the oxygen atoms have a tendency to recombine by the time the oxygen reaches certain chamber surfaces. Combining oxygen radicals, argon radicals, and a nitrogen radicals as described herein increases the oxygen radical density and lifetime (e.g., reduce oxygen radical recombination), thus improving cleaning of process chamber components. The combination of gases as described herein showed improved (e.g., reduced) etch times when compared with other types of cleaning such as in situ radiofrequency cleaning.
The RPS cleaning of the present disclosure cleans films on chamber component surfaces having a film thickness about 4 microns to 6 microns in about 100 seconds to about 200 seconds, such as about 130 seconds to about 170 seconds, such as about 150 seconds. The RPS cleaning of the present disclosure is capable of removing contaminants at an etch rate (ER) of about 10000 angstroms/min to about 80000 angstroms/min, such as about 20000 angstroms/min to about 60000 angstroms/min.
Moreover, the RPS cleaning process described herein exhibits limited ion bombardment and sputtering of etched material onto chamber components when compared to other cleaning methods, such as RF cleaning. Limiting ion bombardment and sputtering reduces damage to the component parts. It has also been discovered that a pressure of the process volume affects clean etch efficiency. In particular, a chamber pressure of about 10 mtorr to about 6 torr, such as about 1 torr to about 4 torr, results in the highest etch efficiency. Without being bound by theory, as pressure exceeds a certain pressure range, collision between radicals is increased, which increases radical recombination, and thus reduces etch rate efficiency. Moreover, if the pressure is below a certain pressure range, the low density of radicals results in radicals not being effectively delivered to the reaction volume. In some embodiments, which can be combined with other embodiments described herein, a process temperature (e.g., substrate temperature) is greater than about 300° C., such as greater than about 600° C.
In summation, method for cleaning one or more chamber components having contaminants is provided. The method includes introducing a gas mixture to a remote plasma source, the gas mixture includes argon, oxygen (or any oxygen-containing gas) and nitrogen (or any nitrogen-containing) gas. A plasma is formed from the gas mixture in the remote plasma source and introduced to a chamber, exposing chamber components to the cleaning plasma. The cleaning plasma has high cleaning efficiency and reduced tendency to damage chamber component surfaces.
Certain features, structures, compositions, materials, or characteristics described herein is combined in any suitable manner in one or more embodiments. Although the present disclosure herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present disclosure. It will be apparent to those skilled in the art that various modifications and variations can be made to the method and systems of the present disclosure. Thus it is intended that the present disclosure include modifications and variations that are within the scope of the appended claims and their equivalents.
