阅读说明：本技术 清洁处理腔室的方法 (Method of cleaning a processing chamber ) 是由 B·S·权 许璐 P·K·库尔施拉希萨 S·李 D·H·李 K·D·李 于 2020-02-07 设计创作，主要内容包括：本公开的实施方式大致关于清洁半导体处理腔室的方法。在一个实施方式中,一种清洁沉积腔室的方法包括以下步骤：将含氮气体流至沉积腔室内的处理区域中；利用射频功率在处理区域中冲击等离子体；将清洁气体引入流体连接至沉积腔室的远程等离子体源；在远程等离子体源中产生清洁气体的反应物质；将清洁气体引入沉积腔室；以及以不同蚀刻速率移除在沉积腔室的内部表面上的沉积物。(Embodiments of the present disclosure generally relate to methods of cleaning semiconductor processing chambers. In one embodiment, a method of cleaning a deposition chamber includes: flowing a nitrogen-containing gas into a processing region within a deposition chamber; striking a plasma in the processing region with radio frequency power; introducing a cleaning gas into a remote plasma source fluidly connected to the deposition chamber; generating reactive species of a cleaning gas in a remote plasma source; introducing a cleaning gas into the deposition chamber; and removing deposits on the interior surfaces of the deposition chamber at different etch rates.)

1. A method of cleaning a deposition chamber, comprising:

flowing a nitrogen-containing gas into a processing region within the deposition chamber;

striking a plasma in the processing region with radio frequency power;

introducing a cleaning gas into a remote plasma source fluidly connected to the deposition chamber;

generating reactive species of the cleaning gas in the remote plasma source;

introducing the cleaning gas into the deposition chamber; and

deposits on the interior surfaces of the deposition chamber are removed at different etch rates.

2. The method of claim 1, wherein the nitrogen-containing gas comprises nitrogen and oxygen.

3. The method of claim 2, wherein the cleaning gas comprises nitrogen and oxygen.

4. The method of claim 3, wherein the cleaning gas comprises fluorine gas.

5. The method of claim 1, wherein the cleaning gas comprises nitrogen trifluoride and oxygen.

6. The method of claim 1, wherein the cleaning gas and the nitrogen-containing gas are flowed into the deposition chamber simultaneously.

7. The method of claim 1, wherein the cleaning gas is flowed into the deposition chamber after the nitrogen-containing gas is flowed into the deposition chamber.

8. A method of cleaning a deposition chamber, comprising:

flowing a nitrogen-containing gas into a processing region within the deposition chamber;

striking a plasma in the processing region with radio frequency power;

introducing a cleaning gas into a remote plasma source fluidly connected to the deposition chamber;

generating reactive species of the cleaning gas in the remote plasma source;

introducing the cleaning gas into the deposition chamber; and

deposits on the interior surfaces of the deposition chamber are removed at different temperatures.

9. The method of claim 8, wherein an upper portion of the deposition chamber is cleaned using the nitrogen-containing gas.

10. The method of claim 9, wherein a lower portion of the deposition chamber is cleaned using the cleaning gas.

11. The method of claim 8, wherein the nitrogen-containing gas comprises nitrogen and oxygen.

12. The method of claim 11, wherein the cleaning gas comprises nitrogen and oxygen.

13. The method of claim 12, wherein the cleaning gas comprises fluorine gas.

14. The method of claim 8, wherein the cleaning gas and the nitrogen-containing gas are flowed into the deposition chamber simultaneously.

15. A method of cleaning a deposition chamber, comprising:

flowing a first gas into a processing region within the deposition chamber;

striking a plasma of the first gas in the processing region with radio frequency power;

introducing a second gas into a remote plasma source fluidly connected to the deposition chamber;

generating reactive species of the second gas in the remote plasma source;

introducing the second gas into the deposition chamber; and

deposits on the interior surfaces of the deposition chamber are removed at different temperatures and etch rates.

Technical Field

Examples disclosed herein generally relate to methods for cleaning semiconductor processing chambers.

Background

In the fabrication of integrated circuits and semiconductor devices, materials are typically deposited on a substrate in a processing chamber, such as a deposition chamber, such as a Plasma Enhanced Chemical Vapor Deposition (PECVD) chamber. The deposition process typically results in deposition of certain materials on the gas distribution showerhead as well as the walls, and components of the deposition chamber. The material deposited on the chamber walls and components can affect the deposition rate from substrate to substrate, and the deposition uniformity across the substrate. Due to such incorrect deposition, repeatability is often difficult to achieve unless the chamber is cleaned.

Accordingly, there is a need for an improved method of cleaning a chamber.

Disclosure of Invention

Embodiments of the present disclosure generally relate to methods of cleaning semiconductor processing chambers. In one embodiment, a method of cleaning a deposition chamber includes: flowing a nitrogen-containing gas into a processing region within a deposition chamber; striking a plasma in the processing region with radio frequency power; introducing a cleaning gas into a remote plasma source fluidly connected to the deposition chamber; generating reactive species of a cleaning gas in a remote plasma source; introducing a cleaning gas into the deposition chamber; and removing deposits on the interior surfaces of the deposition chamber at different etch rates.

In another embodiment, a method of cleaning a deposition chamber includes: flowing a nitrogen-containing gas into a processing region within a deposition chamber; striking a plasma in the processing region with radio frequency power; introducing a cleaning gas into a remote plasma source fluidly connected to the deposition chamber; generating reactive species of a cleaning gas in a remote plasma source; introducing a cleaning gas into the deposition chamber; and removing deposits on the interior surfaces of the deposition chamber at different temperatures.

In another embodiment, a method of cleaning a deposition chamber includes: flowing a first gas into a processing region within a deposition chamber; striking a plasma of a first gas in a processing region with radio frequency power; introducing a second gas into a remote plasma source fluidly connected to the deposition chamber; generating reactive species of a second gas in the remote plasma source; introducing a second gas into the deposition chamber; and removing deposits on the interior surfaces of the deposition chamber at different temperatures and etch rates.

Drawings

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 examples, some of which are illustrated in the appended drawings. It is to be understood, however, that the appended drawings illustrate only typical 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.

FIG. 1 is a partial cross-sectional view of one example of a plasma system.

Fig. 2 is a graph comparing cleaning rates at different electrode spacings.

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 components and features of one embodiment may be beneficially incorporated in other examples without further recitation.

Detailed Description

The present disclosure generally provides methods and apparatus for cleaning deposition chambers, such as those used in the manufacture of integrated circuits and semiconductor devices. Deposition chambers that may be cleaned using the methods described herein may include chambers that may be used to deposit oxides (such as carbon-doped silicon oxide) and other materials. In one example, a plasma chamber is utilized in a Plasma Enhanced Chemical Vapor Deposition (PECVD) system. Examples of PECVD systems that may be adapted to benefit from the embodiments described herein includeA SE CVD system,GT^TMCVD system orCVD systems, all of which are commercially available from applied materials, inc.SE CVD systems (e.g., 200mm or 300mm) have two isolated processing regions that can be used to deposit thin films on substrates, such as conductive films, silanes, carbon doped silicon oxides, and other materials. Although the example embodiments include two processing regions, it is contemplated that the embodiments described herein may be used to advantage in systems having a single processing region or more than two processing regions. It is also contemplated that embodiments described herein may be used to advantage in other plasma chambers, including etch chambers, ion implantation chambers, plasma treatment chambers, stripping chambers, and the like. It is further contemplated that embodiments described herein may be used to advantage in plasma processing chambers available from other manufacturers.

An example of a chamber that may be used to advantage is shown in figure 1. FIG. 1 shows a cross-sectional view of a dual chamber system 100 having two discrete processing chambers 105. Each of the processing chambers 105 is connected to a remote plasma source 110. The remote plasma source 110 generates reactive species of cleaning gases that flow to the interior of the processing chamber 105. Each of the processing chambers 105 also has a showerhead or perforated faceplate 115. Each of the process chambers 105 is coupled to a gas source 120. Each perforated faceplate 115 includes an opening 125 formed therethrough for delivering process gases, or precursors, or cleaning gases from the gas source 120 to a respective processing region 130 and 135 in each of the processing chambers 105.

Although the remote plasma source 110 is shown coupled to the top of the processing chamber 105, the reactive species generated therein may flow to the processing chamber 105 through the top of the processing chamber 105, the sides of the processing chamber 105, or other locations.

Each of the perforated panels 115 is coupled to a power source 140. The power source 140 is configured to generate a plasma between the perforated faceplate 115 and the heated pedestal 145 in each of the processing regions 130 and 135. The heated pedestal 145 is also configured to electrostatically clamp a substrate (not shown). The power source 140 may be a direct current power source or an alternating current power source, such as a Radio Frequency (RF) power source. The plasma is used to dissociate gases (e.g., process gases and cleaning gases) from the gas source 120.

Each of the processing regions 130 and 135 is coupled to a pump 150. The pump 150 is a vacuum pump to remove unused gases and/or byproducts from the processing chamber 105. The pump 150 includes a valve, such as a throttle valve (not shown), for controlling the pressure in the process chamber 105.

In operation, process gases or precursors are supplied from the gas source 120 to the processing regions 130 and 135. The process gas or precursor flows through the openings 125 in the perforated faceplate 115. A plasma of process gases or precursors is formed in each of the processing regions 130 and 135 by the power source 140. The plasma forms or etches a film on or from a substrate (not shown) supported by a heated pedestal 145 in each of the processing regions 130 and 135.

The interior of the processing chamber 105 is cleaned after a number of cycles of forming a film on a substrate or etching a substrate in each of the processing chambers 105. Chamber cleaning processes (also referred to as "lift-off" processes) improve film deposition in semiconductor manufacturing. The chamber cleaning process controls the health of the chamber and the process stability on the substrate. As semiconductor devices utilize higher memory densities, and therefore thicker multi-stack structures (i.e., 3D VNAND, 3D ReRAM, DRAM, NAND, logic, and foundry), the ability to completely clean the chamber in the shortest time increases throughput. In current cleaning processes, as film thicknesses scale to meet high aspect ratio requirements, cleaning times will likewise increase. For example, as the thickness of the hard mask increases by a factor of two, the processing time is expected to be half that of previous generation equipment to meet the same throughput per production tool per hour.

Chemical Vapor Deposition (CVD) using carbon hard masks at temperatures greater than about 400 degrees celsius is one of the most popular hard mask processes for semiconductor device fabrication. This is due to the high etch selectivity of the mask and the chemical simplicity of the cleaning process. Due to the relatively high etch selectivity and ease of deposition, carbon films up to about 10 micrometers (μm) are used as hard masks. However, as next generation devices utilize even thicker multi-stack structures, there is a need to increase throughput. For example, a carbon-based hard mask (single or multiple compositions of C, Si, N, O, F).

As processing of semiconductor devices advances, it is contemplated that the cleaning rate of the chamber may cause a bottleneck in the overall production. Also, insufficiently cleaned chambers can cause residues to build up in the chamber over time and further damage hardware components or limit the ability to refurbish such hardware components.

Traditionally, RF cleaning is used at high temperatures (greater than about 400 degrees celsius). Remote Plasma (RPS) cleaning process using fluorine-based chemistry is attributed to AlF_xParticle formation is not a viable option even though RPS cleaning has a slightly higher etch rate compared to RF cleaning processes. Furthermore, it is currently based on argon (Ar) and oxygen (O)₂) Cannot remove the RF cleaning chemistry in the perforated face plate 115Aluminum oxide carbon (AlO) formed at the opening 125_x). In addition, use is made of a catalyst containing O₂The RF cleaning of the chemistry of (a) provides several challenges, one being insufficient chamber bottom cleaning due to relatively unstable plasma at higher spacings (e.g., the size of the processing regions 130 and 135 between the heated pedestal 145 and the perforated faceplate 115).

Further, AlO formed on the opening 125 of the perforated panel 115_xThe emissivity of the perforated panel 115 is changed. Variations in emissivity cause process drift over time and/or affect substrate-to-substrate repeatability.

According to embodiments disclosed herein, a multi-source plasma cleaning method is provided. The multi-source plasma cleaning methods as described herein greatly increase throughput while efficiently cleaning chamber components compared to conventional cleaning methods.

It has been found through testing that fluorine-based RPS cleaning generally provides cleaning efficiencies superior to RF-only cleaning processes (e.g., in-situ generated plasmas). However, the high power RF cleaning process provides similar or even greater cleaning efficiency at certain regions of the chamber as compared to RPS cleaning. The multi-source plasma cleaning methods as disclosed herein combine RF cleaning with RPS cleaning with excellent results.

For example, provided herein is the use of a power source 140 (between the perforated face plate 115 and the heated pedestal 145) using nitrogen/oxygen (N) for applications in the processing regions 130 and 135₂/O₂) RF cleaning of the mixture. N is a radical of₂/O₂The mixture is about 1-50% N₂For about 99-50% of O₂。N₂/O₂The mixture is provided at a flow rate of about 5L to about 25L (slm). The pressure in the chamber is about 2Torr to about 15 Torr. The RF power is about 1000W to about 5000W while providing a temperature of greater than about 400 degrees celsius in the processing regions 130 and 135.

An RPS cleaning process is provided herein that cooperates with the RF cleaning process described above. The RPS cleaning process cleans the lower portion of the processing chamber 105 using the remote plasma source 110. For example, nitrogen trifluoride/oxygen (NF) is used₃/O₂) The mixture is used to clean the sidewalls 160 of the processing chamber 105 in an RPS cleaning process. The sidewalls 160 are typically much cooler than the components adjacent to the process chambers 105 of the processing regions 130 and 135. For example, when the temperature of the processing regions 130 and 135 is at or above about 400 degrees celsius, the sidewalls 160 are at least 100 degrees celsius cooler. NF₃/O₂The mixture is provided by a cleaning gas source 165 coupled to the processing chamber 105. NF₃/O₂The mixture is excited into a plasma in the remote plasma source 110 and provided to the processing chamber 105 in this excited state. NF₃/O₂The mixture is about 1-50% NF₃For about 99-50% of O₂。NF₃/O₂The mixture is provided at a flow rate of about 5L to about 25L (slm). The pressure in the chamber is about 2Torr to about 15 Torr. The RPS cleaning process may be provided simultaneously with the RF cleaning process, or shortly after the RF cleaning process. For example, an RPS cleaning process is performed after the chamber has been evacuated and after the purging of the RF cleaning process.

The RF cleaning process is used to clean the opening 125 of the perforated faceplate 115 and other portions of the process chamber 105 adjacent to the processing regions 130 and 135. The RF cleaning process is very fast and efficient and removes locally formed AlO in or on the perforated panel 115_x. For example, the opening 125 of the perforated panel 115 is tapered, introducing a low pressure zone adjacent the opening 125. Conventional argon-based deposition processes introduce micro-arcs in this low-pressure region. The carbon film on the alumina perforated panel 115 is converted to aluminum oxycarbide. This aluminum oxycarbide is very difficult or even impossible to pass Ar/O₂RF cleaning chemistry removal. However, using N₂/O₂The cleaning chemistry, aluminum oxycarbide, is completely removed. Then, a brief RPS cleaning will clean the rest of the chamber with very high cleaning efficiency. Again, due to the micro-arc described above, N is used₂/O₂RF cleaning provides an excellent solution to residue formed at the opening 125 of the perforated panel 115. N is a radical of₂/O₂RF cleaning provides an efficient control mechanism for process drift due to emissivity change over time, and also for process driftSubstrate slip/electrostatic chucking stability of the substrate on the heated pedestal 145 provides a control mechanism.

Fig. 2 is a graph 200 showing the difference in cleaning rate at different electrode spacings (the distance between the perforated face plate 115 and the heated base 145). Curve 205 shows N as described herein₂/O₂Performance of the RF cleaning process. N is a radical of₂/O₂RF cleaning method and NF as described herein₃/O₂The RPS cleaning method (shown by curve 210) is compared. The RF clean has a cleaning (etch) rate at the top of the chamber (near the processing regions 130 and 135) that is comparable to the RPS cleaning (etch) rate. However, as the pitch increases, N₂/O₂The cleaning rate is greatly reduced.

In contrast, NF₃/O₂The RPS cleaning method does not drop so much, even at the bottom of the chamber. NF at the bottom of the chamber₃/O₂Cleaning rate ratio N of RPS₂/O₂The cleaning rate of the RF cleaning mode is about six times. Furthermore, due to NF induction from RPS₃/O₂The chambers below the processing regions 130 and 135 are primarily cleaned so the on time of the remote plasma source 110 is minimized. This also causes AlF on the chamber walls 160 due to the reduction of fluorine provided to the chamber interior_xThe formation of (a) is minimized. In addition, any AlF formed on the chamber components_xFalls to the bottom of the chamber where it can be removed by the pump 150 rather than falling on the substrate being processed.

At increased high RF power (about a two-fold increase), the multi-source plasma cleaning methods described herein exhibit cleaning efficiencies that are approximately related to the applied RF power, but the cleaning efficiencies drop off sharply as the pitch becomes larger.

In many manufacturing processes, a post-deposition clean is followed by a chamber seasoning process to condition the chamber surfaces. As described above, the nitrogen-oxygen based RF plasma passivates the aluminum oxycarbide surface removing aluminum nitride, and again minimizes AlF by restoring the aluminum oxynitride surface in addition to forming a polymeric C-N layer_xIs performed.

The presence of the polymeric C-N layer provides multiple benefits. A first benefit of polymerizing the C-N layer is to increase the coefficient of friction of the heated mount 145 (made of aluminum nitride (AlN)). The increased coefficient of friction reduces substrate slip, which mitigates false positive instances of arcing, out-of-specification in-film defect occurrence, substrate chipping and hardware damage, chucking loss, and backside penetration. Previous strategies for mitigating substrate slip have exhibited reduced substrate center errors with independent disposal as preventive maintenance or to restore out-of-specification performance. Using N₂/O₂The manner in which the RF plasma develops occurs in parallel with cleaning and maintains the substrate at central performance quality.

A second benefit of the C-N layer is minimizing AlF due to exposure to fluorine-based RPS cleaning_xIs performed. Because C-N is highly resistant to fluorine-based etching, AlN under the C-N film layer will be protected from fluorine radicals. Furthermore, AlN actively resists N during RF cleaning₂/O₂Plasma, thereby mitigating AlF_xThe resulting heater was damaged as demonstrated by a repeatability test showing stable film properties for over 500 substrates. Repeatability tests show stable deposition rate, uniformity and in-gauge film properties with reduced defects.

Utilizing the multi-source plasma cleaning methods described herein, successful implementations of high throughput processing are provided at temperatures greater than about 400 degrees celsius. The multi-source plasma cleaning described herein may be applied to any other process (e.g., oxidation/nitridation/doped carbon process) configured for a high throughput chamber with high RF power and RPS cleaning. The multi-source plasma cleaning methods described herein provide enhanced quality control by providing a high throughput solution.

While the foregoing is directed to examples of the present disclosure, other and further examples of the disclosure may be derived without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.