Method for cleaning silicon carbonitride deposits using modified cleaning chemicals to improve cleaning efficiency and increase throughput by reducing cleaning time

Abstract

The present application relates to methods for cleaning silicon carbonitride deposits using modified cleaning chemicals to improve cleaning efficiency and increase throughput by reducing cleaning time. In particular, the present invention provides a method of cleaning a chamber of a plasma processing device to remove deposits formed after the plasma processing device has been used to deposit a dielectric material including silicon and carbon, and also provides a plasma processing device.

Description

[0001] The present invention relates to a method for cleaning a chamber of a plasma processing device. The present invention also relates to a plasma processing device. Background Art

[0002] The manufacture of devices such as semiconductor devices often involves the deposition of films such as dielectric films, which include silicon oxides, SiN, SiC, SiOC, and SiCN. In many back-end (BEOL) and packaging applications, it is also required to deposit these films at relatively low temperatures below 450°C to prevent damage or deformation of the components, which may affect the deposition technology of these films in a cost-effective manner. The most widely used technology for depositing low-temperature films is plasma enhanced chemical vapor deposition (PECVD), which uses plasma to decompose precursors in a chamber containing a substrate for deposition. This technology can produce excellent low-temperature film properties at relatively high deposition rates. However, deposition is not limited to the substrate surface because the plasma extends beyond the substrate surface. Over time, this causes the deposited material to accumulate in the chamber. This deposited material may become a source of particles that contaminate future deposition processes, so it is necessary to remove and surface treat the interior of the chamber. Ideally, the interior surfaces of the PECVD process chamber are cleaned and may be coated without breaking the vacuum in order to maintain production operation of the system. The frequency of these cleaning cycles will depend on the thickness of the deposited material and the process conditions, such as deposition temperature, plasma power, and precursors used to form the desired film.

[0003] In a capacitively coupled parallel plate PECVD system, the deposition plasma is generated by flowing process gases into the chamber under reduced pressure and applying an RF potential between a "shower head" or gas distribution plate and a substrate support on which the substrate is placed. After the deposition cycle, when the substrate has been removed from the system, a cleaning gas can be introduced into the chamber through the shower head, and an RF potential can then be applied to clean the interior surfaces of the chamber. This chamber cleaning step can be performed after each substrate or a series of substrates, where the frequency of the cleaning step is determined by the efficacy of the cleaning step to control particle generation. Subsequently, if necessary, a "sticking" deposition step can be performed to coat the surface of the chamber. This step helps to cover any residual compounds remaining in the chamber due to the cleaning step and provides a consistent surface coating. Although this process gas change sequence is easy to achieve in practice, the cleaning process has limitations, mainly due to the relatively high ratio of free ions to free radicals in the RF plasma. Over time, the ion components tend to make the chamber components rough, and the ion density varies significantly throughout the chamber, resulting in some areas of the chamber requiring long periods of time to clean, while other areas are overexposed. These problems can be solved using a remote plasma source located outside the chamber, which produces a high radical concentration with a relatively low ion density. However, these sources add system complexity and cost, and their performance depends on the composition of the deposited species that accumulate on chamber components.

[0004] The productivity of PECVD is determined by the number of substrates processed in a fixed period of time. When the system is not depositing a film on a substrate, during a cleaning step or a pre-deposition step, when no substrate is present in the chamber, production time is wasted. In a production environment, it is critical to maximize the time spent depositing a film on a substrate while maintaining a stable process within acceptable defectivity limits.

[0005] PECVD deposited dielectrics such as silicon oxide, SiN, and SiOC can be easily used from dissociated NF 3 Fluorine free radical F* etching. 3 Remote plasma etching of SiO 2 The reaction mechanisms can be seen in (1) and (2) below.

[0006] (1) 2 NF 3 (g) → N 2 (g) + 6 F*

[0007] (2) SiO 2 (s) + 4 F* → SiF 4 (g) + O 2 (g)

[0008] SiCN and SiC films with high C content (typically greater than 20 at % C) cannot be effectively removed by F* radicals alone because silicon is preferentially removed, resulting in residual carbon-based byproducts remaining in the chamber even after long cleaning times.

[0009] Therefore, there is a need for a method of effectively cleaning a PECVD chamber to maximize production time while maintaining film quality, substrate-to-substrate and intra-substrate uniformity, rate and defectivity within acceptable limits. By keeping cleaning time to a minimum, cleaning gas consumption can also be reduced, which in turn has cost and environmental benefits. Summary of the invention

[0010] The present invention, in at least some of its embodiments, seeks to address the above-described problems, desires and needs.

[0011] According to a first aspect of the present invention, there is provided a method of cleaning a chamber of a plasma processing device to remove deposits formed after the plasma processing device has been used to deposit a dielectric material comprising silicon and carbon, the method comprising the steps of:

[0012] ● introducing a first cleaning gas mixture into the chamber through a first gas inlet in a first introducing step, the first cleaning gas mixture comprising a first oxygen-containing component;

[0013] • generating a first plasma from said first cleaning gas mixture in said chamber in a first cleaning step;

[0014] ● introducing a second cleaning gas mixture into the remote plasma source in a second introducing step, wherein the second cleaning gas mixture includes a fluorine-containing component;

[0015] ● generating a second plasma from a second cleaning gas mixture in the remote plasma source in a remote plasma generating step, wherein the second plasma comprises fluorine radicals; and

[0016] - performing a second cleaning step by allowing fluorine radicals from the second plasma to enter the chamber and simultaneously with the fluorine radicals from the second plasma introducing a third cleaning gas mixture into the chamber, wherein the third cleaning gas mixture includes a second oxygen-containing component.

[0017] Without wishing to be bound by theory or speculation, it is believed that the first plasma generated in the chamber provides ion bombardment to rapidly oxidize the deposits and produce modified deposits. However, since this first plasma does not remove the deposits, ion damage to chamber surfaces and internal components is minimized. Fluorine radicals and a second oxygen-containing component generated in a second plasma in a remote plasma source are subsequently introduced into the chamber to cause activation of the second oxygen-containing component to further oxidize the deposits while increasing the residence time of the fluorine radicals, allowing for more efficient removal of the modified deposits.

[0018] For the avoidance of doubt, the term 'free radical' is intended to refer to an uncharged reactive species having one or more unpaired electrons. Free radicals may be atomic or molecular. It is expected that substantially all (95% or more) of the electrons and ions generated in the remote plasma source will not reach the chamber.

[0019] The third cleaning gas mixture can be introduced into the chamber separately from the fluorine radicals from the second plasma. The third cleaning gas mixture can be introduced into the chamber through the first gas inlet. The fluorine radicals can be introduced into the chamber through a connector connecting the chamber and the remote plasma source. The chamber may include a gas inlet system, which acts as a conduit for the free radicals generated in the remote plasma source and the first cleaning gas mixture and the second cleaning gas mixture. The gas inlet system may include a showerhead. As is well known to skilled readers, a showerhead is a gas supply element having a plurality of perforations or other apertures. The perforations or other apertures allow gas to be uniformly introduced into the chamber. Typically, the showerhead includes a first plate having at least one gas inlet and a second plate carrying the perforations or other apertures. The first plate and the second plate are spaced apart to define a cavity. The gas inlet system may include the first gas inlet. The gas inlet system may include the second gas inlet.

[0020] The dielectric material may include silicon carbon nitride or silicon carbide. The dielectric material may include hydrogenated silicon carbon nitride (SiCN:H). The dielectric material may include amorphous carbon. The dielectric material may include at least 20 at.% carbon. The dielectric material may include at least 30 at.% carbon.

[0021] The plasma processing device may be a PECVD device. The remote plasma source may be an inductively coupled plasma (ICP) source or any other suitable plasma source. The plasma generating component may be a capacitively coupled parallel plate system driven by radio frequency (RF). The plasma processing device may include a substrate support located within the chamber. The method may be performed after plasma treatment of one or more substrates. The one or more substrates may include one or more semiconductor substrates. The one or more semiconductor substrates may include one or more silicon substrates. The one or more semiconductor substrates may include one or more semiconductor wafers, such as one or more silicon wafers. The method may be performed after an isolation or passivation plasma treatment step. The method may be performed after TSV by revealing or interposer manufacturing plasma treatment steps.

[0022] The first oxygen-containing component may be selected from O 2 、N 2 O and O 3 The first oxygen-containing component may be O 2 The second oxygen-containing component may be selected from O 2 、N 2 O and O 3 The second oxygen-containing component may be O 2 The fluorine-containing component may be NF 3 . The first cleaning gas mixture may include at least one inert gas component. The at least one inert gas component of the first cleaning gas mixture may include Ar and / or He. The second cleaning gas mixture may include at least one inert gas component. The inert gas component of the second cleaning gas mixture may include Ar and / or He. Adding at least one inert gas component (such as Ar or He) to the cleaning gas mixture used to generate the first plasma and / or the second plasma may facilitate the initiation of plasma and stabilize the generated plasma.

[0023] The ratio of the flow rate of the fluorine-containing component in sccm to the flow rate of the second oxygen-containing component in sccm may be about 4:1 to about 2:3. The ratio of the flow rate of the fluorine-containing component in sccm to the flow rate of the second oxygen-containing component in sccm may be about 3:2. The flow rate of the first oxygen-containing component may be about 200 sccm to about 2000 sccm. The flow rate of the first oxygen-containing component may be about 1000 sccm. The flow rate of the fluorine-containing component may be about 1000 sccm to about 5000 sccm. The flow rate of the fluorine-containing component may be about 3000 sccm. The flow rate of the second oxygen-containing component may be about 1000 sccm to about 5000 sccm. The flow rate of the second oxygen-containing component may be about 2000 sccm.

[0024] The chamber may be maintained under vacuum by a vacuum member such as a vacuum pump. During the first introduction step and / or the first cleaning step, the chamber may be maintained at a pressure of about 500mTorr (66700Pa) to about 5000mTorr (667000Pa). During the first introduction step and / or the first cleaning step, the chamber may be maintained at a pressure of about 1000mTorr (133000Pa). During the second cleaning step, the chamber may be maintained at a pressure of about 500mTorr (66700Pa) to about 5000mTorr (667000Pa). During the second cleaning step, the chamber may be maintained at a pressure of about 2500mTorr (333000Pa).

[0025] During the first cleaning step, a high frequency RF power may be used to maintain a plasma in the chamber. During the first cleaning step, a high frequency RF power and a low frequency RF power may be used to maintain a plasma in the chamber. The frequency of the high frequency RF power may be 10 MHz to 20 MHz. The frequency of the low frequency RF power may be 375 kHz to 2 MHz. During the first cleaning step, the high frequency RF power may supply a power of about 500 W to about 1500 W. During the first cleaning step, the high frequency RF power may supply a power of about 1000 W.

[0026] The duration of the first cleaning step may be from about 20 seconds to about 60 seconds. The duration of the first cleaning step may be about 30 seconds.

[0027] The second cleaning step may include monitoring the composition of the environment in the chamber, and determining the endpoint of the second cleaning step based on the composition of the environment in the chamber. The composition of the environment in the chamber may be monitored by an infrared gas analyzer.

[0028] During the second cleaning step, no plasma may be generated in the chamber.

[0029] The method may further include the step of performing a pre-deposition chamber treatment after the second cleaning step.

[0030] According to a second aspect of the present invention, there is provided a plasma processing device comprising:

[0031] ● Room;

[0032] - plasma generating means configured, in use, to generate plasma within the chamber;

[0033] ● at least one gas inlet;

[0034] A remote plasma source configured to generate a plasma in use;

[0035] a connector connecting the remote plasma source to the chamber, wherein the connector is configured, in use, to allow radicals from a plasma generated in the remote plasma source to enter the chamber while preventing a majority of ions generated in the remote plasma source from entering the chamber; and

[0036] Controller,

[0037] The controller is configured, in use:

[0038] • introducing a first cleaning gas mixture into the chamber through a first gas inlet of the at least one gas inlet, the first cleaning gas mixture comprising a first oxygen-containing component;

[0039] • generating a first plasma from the first cleaning gas mixture using the plasma generating means in the chamber;

[0040] ● introducing a second cleaning gas mixture into the remote plasma source, wherein the second cleaning gas mixture includes a fluorine-containing component;

[0041] • generating a second plasma from a second cleaning gas mixture in the remote plasma source, wherein the second plasma comprises fluorine radicals; and

[0042] - allowing fluorine radicals from the second plasma to enter the chamber through the connector, and simultaneously with the fluorine radicals from the second plasma introducing a third cleaning gas mixture into the chamber, wherein the third cleaning gas mixture includes a second oxygen-containing component.

[0043] The plasma processing device may be a PECVD device. The remote plasma source may be an inductively coupled plasma (ICP) source or any other suitable plasma source. The plasma generating means may be a radio frequency (RF) driven capacitively coupled parallel plate system.

[0044] The controller may be configured to, in use, introduce the third cleaning gas mixture into the chamber through at least one gas inlet. The plasma processing device may include a monitoring device configured to monitor, in use, the composition of the environment within the chamber, wherein the controller is configured to, in use, determine the endpoint of the second cleaning step based on the composition of the environment within the chamber as monitored by the monitoring device. The monitoring device may include an infrared gas analyzer.

[0045] The connector may be electrically insulating. The connector may be formed of a dielectric material such as ceramic. The connector may include a plurality of gas conducting holes. The diameter of each of the gas conducting holes may be less than 10 mm, preferably less than 5 mm. In this way, the plasma generated in the remote plasma source is substantially prevented from reaching the chamber. The connector may include a plug having a plurality of gas conducting holes formed therethrough.

[0046] The chamber may include a gas inlet system that acts as a conduit for free radicals generated in the remote plasma source. The gas inlet system may include a showerhead. The gas inlet system may include the first gas inlet. The gas inlet system may include the second gas inlet. The gas inlet system may include additional gas inlets, such as a third gas inlet. The plasma processing device may include a substrate support located within the chamber.

[0047] For the avoidance of doubt, whenever reference is made herein to 'comprising' or 'including' and similar terms, the invention should also be understood to encompass more restrictive terms such as 'consisting of' and 'consisting essentially of'. Although the invention has been described above, the invention extends to any creative combination of the features set out above, or in the following description, drawings or claims. For example, any feature disclosed in relation to the first aspect of the invention may be combined with any feature of the second aspect of the invention, and vice versa. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Aspects of the method and apparatus according to the present invention will now be described with reference to the accompanying drawings, in which:

[0049] Figure 1 is a schematic representation of a plasma processing device according to an embodiment of the present invention;

[0050] Figure 2 is a graph showing the relative intensity of volatile components in a chamber versus the duration of a comparative cleaning step;

[0051] Figure 3 is a graph showing the relative intensity of volatile components in a chamber versus the duration of a comparative cleaning step;

[0052] Figure 4 is a graph showing the relative intensity of volatile components in a chamber versus the duration of a comparative cleaning step;

[0053] Figure 5is a graph showing the relative intensity of volatile components in a chamber versus the duration of a comparative cleaning step; and

[0054] Figure 6 is a flow chart illustrating a method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0055] Figure 1 A schematic representation of a PECVD system 1 according to an embodiment of the present invention is shown. Within the chamber 2, a process zone 3 in which plasma is generated is defined between a substrate support 5 and a gas inlet system including a showerhead 4. Gases are passed into the rear of the showerhead 4 and projected into the process zone 3 through a series of small holes 10, which are isolated within the showerhead 4 by an internal gas distribution plate 11. The substrate support 5 is grounded, and the showerhead 4 is powered by a plasma generation component, which includes two different RF power supplies 14, 15, each operating at a different RF frequency, and their associated matching units 16, 17. There is a dielectric break (not shown) between the aluminum showerhead 4 and the metal chamber 2. Alternative plasma generation components may also be used, such as where the substrate support 5 is RF driven and the gas distribution plate 11 is grounded. Process gases and cleaning gases enter the gas inlet system through pipes 6, 7 including isolation values ​​8, 9. Multiple gas sources are connected to the pipes 6, 7 through a manifold (not shown) with isolation valves, mass flow controllers and related components. Chamber 2 is evacuated through line 12 by means of a pump (not shown).

[0056] A typical process cycle will begin by loading the substrate into the evacuated chamber 2 and placing the substrate onto the substrate support 5. An annular uniformity ring 13 is located near the edge of the substrate on the substrate support surface. The process gas or gas mixture enters the system through the gas conduit 6 with the valve 8 open, and enters the chamber 2 through the showerhead 4. When the desired gas flow and pressure are achieved by the system controller, one or both of the RF power supplies 14, 15 deliver RF power to the showerhead 4, thereby initiating a plasma in the chamber 2 between the showerhead 4 and the substrate support 5. The high frequency RF power supply 14 typically operates at 10-20 MHz, while the low frequency RF power supply 15 typically operates at 375 kHz–2 MHz. Matching units 16 and 17 enable RF to be effectively coupled into the showerhead 4. When the desired deposition thickness is achieved, the power is turned off and the process gas flow is stopped. The chamber 2 is evacuated, and the substrate is then removed from the chamber.

[0057] In a typical remote chamber cleaning process, reactive cleaning gas and any inert gas pass through gas conduit 7, connector 20, remote plasma source 18 and valve 9, through showerhead 4 and into chamber 2. Power is then delivered from power supply 19 to remote source 18 to generate a high density plasma in remote source 18, which in turn provides a source of free radicals to clean chamber 2 through connector 20. Connector 20 may be disposed at any location downstream of remote source 18 before showerhead 4. Connector 20 may be electrically insulating, such as a dielectric connector, and may be provided with a plurality of gas conducting holes having a diameter of less than 10 mm to ensure that energetic ions in the plasma generated in remote plasma source 18 do not reach chamber 2, but free radicals do reach chamber 2.

[0058] To determine the chamber cleaning endpoint, a monitoring device 21, in this case an infrared gas analyzer, is used in the exhaust line 12. By monitoring the characteristics (such as IR signature) of the gases and volatile components leaving the chamber 2 through the exhaust line 12, it is possible to map the intensity of the emissions as a function of time and thereby determine when the chamber 2 has been completely cleaned. The system 1 further includes a controller 22 configured to control each component of the system 1 in both normal operating mode and cleaning mode.

[0059] The experiments were performed using a Delta 100 manufactured by SPTS of Newport, UK. TM The PECVD process was performed on an MKS Astron 3000 fxPPECVD system. This is a capacitively coupled hybrid frequency parallel plate single wafer PECVD system. Silicon carbon nitride films ranging from 150nm to 500nm thickness were deposited on bare silicon wafers using a standard 300mm silicon wafer thickness of approximately 775μm, and the cleaning parameters were modified to determine the optimal cleaning process chemistry and physics. However, alternative plasma processing systems, substrate materials, substrate sizes, and dielectric films including silicon and carbon may also be used. The MKS Astron 3000 fxPPECVD system was used to perform the PECVD process. TM A reactive gas generator is used as a remote source. Other forms of plasma generators may be considered alternatively. All cleaning cycles use the same deposition thickness and silicon carbon nitride film. The endpoint time contains a fixed overetch period to support long-term chamber performance. At temperatures below 450°C, silicon carbon nitride films deposited by PECVD under standard BEOL conditions have significant hydrogen content and are therefore more accurately defined as SiCN:H films. However, for simplicity, such films and deposits are referred to as SiCN.

[0060] In the first comparative example, remote plasma NF was performed after SiCN deposition. 3 Clean. The end point trajectory results of the monitoring of gas composition and volatile compounds are as follows Figure 2, where the X-axis indicates the cleaning time and the Y-axis shows the relative intensity of volatile compounds in the exhaust line. After about 25 seconds, the emissions peaked and then dropped rapidly for about 50 seconds and then slowly dropped until the remote plasma was extinguished. Even after about 300 seconds, volatile products were still detected in the exhaust line, indicating that the endpoint had not been reached and the chamber was not completely cleaned. It was determined that an additional 200 seconds of remote plasma generation was required to complete the cleaning of the chamber and reach the endpoint. In comparison, under similar process conditions, SiO2 of comparable thickness was produced. 2 Deposition will require less than 80 seconds to reach a clean endpoint.

[0061] In a second comparative example, the cleaning method was then modified to include a capacitive RF oxygen plasma in the PECVD chamber at a chamber pressure of 1000 mTorr for a duration of 60 seconds prior to the remote plasma source cleaning. 1000 sccm O was introduced through the showerhead in the first introduction step. 2 The O2 gas flow was introduced into the PECVD chamber, and in the first cleaning step, 1000 W of high frequency RF power was coupled into the PECVD chamber through a showerhead to ignite the O2 gas flow. 2 During the first cleaning step, no significant CO or CO 2 IR absorption, as monitored by an infrared gas analyzer. Without wishing to be bound by theory or speculation, it is believed that rather than removing the SiCN deposits, the carbon content within the SiCN deposits is oxidized by the oxygen-containing plasma to form SiCON-modified deposits. These modified SiCON deposits can then be more effectively etched in a subsequent remote plasma clean.

[0062] Figure 3 Shown with Figure 2 The comparative examples shown are compared to the NF 3 The effect of the initial RF oxygen plasma before the remote plasma cleaning step. 3 The intensity of the integrated emissions increased significantly compared to the equivalent deposition for the remote plasma clean. This suggests that although both methods reached the cleaning endpoint at approximately the same time, as measured by the IR detector, there may be residual non-volatile material in the chamber after the method including the initial oxygen-containing plasma clean.

[0063] It has been found that using a gas flow rate of 200 to 2000 sccm and an RF power of 500 to 1500 W, a stable RF oxygen plasma can be maintained at a pressure of 500 to 5000 mTorr in the chamber, providing a wide process window for the first cleaning step.

[0064] Modification of the remote cleaning chemistry for the second cleaning step was then investigated in a third comparative example by maintaining a pressure of 2500 mT in the chamber with a total reactive gas flow of 5000 sccm and varying the NF 3 The flow rates were adjusted to establish the optimized process conditions. Each test was performed without the first cleaning step using an oxygen-based plasma in the chamber. In the cleaning of SiCN deposits, the optimal ratio was determined to have 2000 sccm of the oxygen-containing component (in this case O 2 gas) of 3000sccm to reduce NF 3 flow rate. However, it is expected that this particular optimal ratio will depend on the nature of the deposit to be removed. Without wishing to be bound by any theory or speculation, it is believed that the addition of the oxygen-containing component to the remotely generated plasma causes activation of the oxygen-containing component, thereby allowing oxidation of the constituent carbon in the SiCN deposit. It has also been determined that by mixing the remotely ionized free fluorine radicals with the oxygen-containing component within the PECVD showerhead and chamber rather than in the remote source, the residence time of the fluorine radicals is increased, thereby allowing for more efficient etching of the modified SiCON deposit. Figure 4 As shown and summarized in Table 1, these effects combine to reduce the time to completely clean chamber deposits:

[0065] <![CDATA[NF 3 :O 2 Ratio]]> Cleaning time (seconds) 5:0 >200 4:1 185 3:2 170 2:3 185

[0066] Table 1: NF at 2500mTorr 3 :O 2 SiCN cleaning time for ratios from 5:0 to 2:3

[0067] The first cleaning step comprising an oxygen-containing plasma is then combined with a subsequent modified remote plasma cleaning step to further reduce the time it takes for the chamber cleaning to be completed. The combination of a first cleaning step (comprising the generation of a first plasma in a chamber comprising an oxygen-containing component) and a second cleaning step (comprising the generation of a plasma from a fluorine-containing component in a remote source, followed by cleaning the chamber by fluorine radicals and oxygen-containing components) was determined to reduce the chamber cleaning time and prevent the accumulation of residues in the PECVD chamber, which may hinder the long-term performance of the chamber through particle generation. This is evidenced by trace amounts of residues found after deposition and during inspection of the clean chamber. In the absence of a first plasma cleaning, a yellow / orange coating was observed to gradually form on interior surfaces (such as the liner and showerhead of the chamber) during bulk deposition. However, no such coating was observed when cleaning with the combined first cleaning step and second cleaning step of the present invention.

[0068] Figure 5A comparison between a standard remote plasma cleaning, a modified remote plasma cleaning and a combined first cleaning step and a second cleaning step according to the present invention is shown. Figure 5 It can be seen that when the first cleaning step is combined with a subsequent second cleaning step, the peak intensity of the IR gas analyzer signal for Si-F and etch rate increases compared to the modified remote cleaning alone. Table 2 shows the best achieved cleaning times for the individual cleaning modifications and the combination of cleaning modifications.

[0069]

[0070]

[0071] Table 2: Total cleaning times for SiCN PECVD deposition for different cleaning methods and chemistries. *Based on endpoint data.

[0072] Figure 6 A method of cleaning a chamber of a plasma processing device (in this case a PECVD device) to remove deposits formed after the plasma processing device has been used to deposit dielectric materials including silicon and carbon is summarized in accordance with an exemplary embodiment of the present invention. In a first introduction step 101, a first cleaning gas mixture including a first oxygen-containing component is introduced into the PECVD chamber with any substrate removed from the chamber and the chamber evacuated of previous gases or volatile components. In one embodiment, the first cleaning gas mixture includes O 2 Gas or a composition thereof, the O 2 Gas is introduced into the chamber to achieve a partial pressure of about 1000 mT. In a first cleaning step 102, a first plasma is generated in the chamber between the showerhead and the wafer support by applying RF power for about 30 seconds to oxidize the carbon content of the deposit. The exact duration of the first cleaning step depends on the thickness and carbon content of the deposit. The RF plasma is then extinguished. In a second introduction step 103, a second cleaning gas mixture including a fluorine-containing component (in this case NF 3 ) is injected into the remote plasma source. In the remote plasma generation step 104, when power is applied to the remote plasma source to generate fluorine radicals, the fluorine-containing component dissociates. In the second cleaning step 105, the fluorine radicals and a third cleaning gas mixture including a second oxygen-containing component (in this case, O 2Gas) is delivered to the showerhead and introduced into the chamber to clean the modified deposit. Preferably, during the second cleaning step, no plasma is generated in the chamber to prevent ion damage to the exposed surfaces and internal components of the chamber when removing the deposit. The duration of the second cleaning step will depend on the deposit composition and thickness, and can be carried out for a set period of time, or if an endpoint is monitored, the second cleaning step will be terminated when the endpoint is determined and the cleaning process is completed. At the endpoint, all gases are pumped out of the chamber and, if necessary, the chamber is purged before any pre-deposition chamber processing steps. At this point, the chamber is then ready for subsequent substrate processing.

[0073] Without being bound by any particular theory or speculation, it is believed that the first plasma in the chamber oxidizes the carbon content of the deposit and produces a modified deposit, such as the absence of CO and CO in the exhaust line. 2 The first plasma provides ion bombardment to rapidly oxidize the deposits. However, since this high energy plasma does not remove the deposits itself, ion damage to the chamber surfaces is avoided. In the second introduction step and the second cleaning step, by not mixing the fluorine-containing components in the remote source with the oxygen-containing components, the fluorine radical density in the chamber is increased due to reduced recombination, and thus the deposition etch rate is increased, while the O 2 Dissociates upon reaching the showerhead to facilitate further modification of the deposition.

Claims

1. A method of cleaning a chamber of a plasma processing device to remove deposits formed after the plasma processing device has been used to deposit a dielectric material comprising silicon and carbon, the method comprising the steps of: ● introducing a first cleaning gas mixture into the chamber through a first gas inlet in a first introducing step, the first cleaning gas mixture comprising a first oxygen-containing component; • generating a first plasma from said first cleaning gas mixture in said chamber in a first cleaning step; ● introducing a second cleaning gas mixture into the remote plasma source in a second introducing step, wherein the second cleaning gas mixture includes a fluorine-containing component; ● generating a second plasma from a second cleaning gas mixture in the remote plasma source in a remote plasma generating step, wherein the second plasma comprises fluorine radicals; and - performing a second cleaning step by allowing fluorine radicals from the second plasma to enter the chamber and introducing a third cleaning gas mixture into the chamber simultaneously with the fluorine radicals from the second plasma, wherein the third cleaning gas mixture includes a second oxygen-containing component.

2. The method of claim 1, wherein the third cleaning gas mixture is introduced into the chamber separately from the fluorine radicals from the second plasma.

3. A method according to claim 1 or claim 2, wherein the dielectric material comprises silicon carbon nitride or silicon carbide.

4. The method of any one of claims 1 to 3, wherein the dielectric material comprises at least 20 at. % carbon.

5. The method according to any one of claims 1 to 4, wherein the first oxygen-containing component is O2.

6. The method according to any one of claims 1 to 5, wherein the second oxygen-containing component is O2.

7. The method according to any one of claims 1 to 6, wherein the fluorine-containing component is NF3.

8. The method of any one of claims 1 to 7, wherein a ratio of a flow rate in sccm of the fluorine-containing component to a flow rate in sccm of the second oxygen-containing component is from about 4:1 to about 2:

3.

9. The method of claim 8, wherein a ratio of a flow rate of the fluorine-containing component in sccm to a flow rate of the second oxygen-containing component in sccm is about 3:

2.

10. The method of any one of claims 1 to 9, wherein the flow rate of the fluorine-containing component is from about 1000 seem to about 5000 seem. The method of claim 10 , wherein the flow rate of the fluorine-containing component is about 3000 sccm.

12. The method of any one of claims 1 to 11, wherein the flow rate of the second oxygen-containing component is from about 1000 seem to about 5000 seem.

13. The method of claim 12, wherein the flow rate of the second oxygen-containing component is about 2000 seem.

14. The method of any one of claims 1-13, wherein during the first introducing step, the chamber is maintained at a pressure of about 500 mTorr (66700 Pa) to about 5000 mTorr (667000 Pa).

15. The method of any one of claims 1-14, wherein during the first cleaning step, the chamber is maintained at a pressure of about 500 mTorr (66700 Pa) to about 5000 mTorr (667000 Pa).

16. The method of any one of claims 1-15, wherein during the second cleaning step, the chamber is maintained at a pressure of about 500 mTorr (66700 Pa) to about 5000 mTorr (667000 Pa).

17. The method of any one of claims 1 to 16, wherein during the first cleaning step, the plasma is maintained in the chamber using high frequency RF power.

18. The method of claim 16, wherein during the first cleaning step, the high frequency RF power supplies a power of about 500 W to about 1500 W.

19. The method of any one of claims 1 to 18, wherein the duration of the first cleaning step is from about 20 seconds to about 60 seconds.

20. The method of any one of claims 1 to 19, wherein the second cleaning step comprises monitoring the composition of the environment within the chamber, and determining an endpoint of the second cleaning step based on the composition of the environment within the chamber.

21. The method of any one of claims 1 to 20, wherein during the second cleaning step, no plasma is generated in the chamber.

22. The method of any one of claims 1 to 21, wherein the method further comprises the step of performing a pre-deposition chamber treatment after the second cleaning step.

23. A plasma processing device comprising: ● Room; - plasma generating means configured, in use, to generate plasma within the chamber; ● at least one gas inlet; A remote plasma source configured to generate a plasma in use; a connector connecting the remote plasma source to the chamber, wherein the connector is configured, in use, to allow radicals from a plasma generated in the remote plasma source to enter the chamber while preventing a majority of ions generated in the remote plasma source from entering the chamber; as well as Controller, Wherein the controller is configured, in use: • introducing a first cleaning gas mixture into the chamber through a first gas inlet of the at least one gas inlet, the first cleaning gas mixture comprising a first oxygen-containing component; • generating a first plasma from the first cleaning gas mixture using the plasma generating means in the chamber; ● introducing a second cleaning gas mixture into the remote plasma source, wherein the second cleaning gas mixture includes a fluorine-containing component; - generating a second plasma from a second cleaning gas mixture in the remote plasma source, wherein The second plasma includes fluorine radicals; and - allowing fluorine radicals from the second plasma to enter the chamber through the connector, and simultaneously with the fluorine radicals from the second plasma introducing a third cleaning gas mixture into the chamber, wherein the third cleaning gas mixture includes a second oxygen-containing component.

24. The plasma processing device of claim 23, wherein the plasma processing device is a PECVD device.

25. A plasma processing device according to claim 23 or claim 24, wherein the controller is arranged, in use, to introduce the third cleaning gas mixture into the chamber through at least one gas inlet.

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