Chamber precoat

Abstract

Techniques described herein relate to methods for preparing a semiconductor processing apparatus for processing substrates, as well as the resulting apparatus. In one aspect, the method includes depositing a precoat on exposed surfaces within a processing chamber of the semiconductor processing apparatus, where the precoat comprises a doped carbon film, and where the precoat is deposited on the exposed surfaces within the processing chamber in the absence of a substrate in the processing chamber. In many examples, the apparatus is configured to deposit a carbon-based material such as an ashable hardmask. In various examples, the precoat is a silicon-doped carbon film. Other types of precoats may be used in other cases.

Description

Attorney Docket No. LAM1P025WO-11824-1WO CHAMBER PRECOAT RELATED APPLICATION(S)

[0000] A PCT Request Form is filed concurrently with this specification as part of the present application. Each application that the present application claims benefit of or priority to as identified in the concurrently filed PCT Request Form is incorporated by reference herein in its entirety and for all purposes. BACKGROUND

[0001] The apparatuses used to manufacture semiconductor devices are typically made from metal such as aluminum. For example, such apparatuses often include one or more processing chamber where semiconductor substrates are processed, and the walls of such chambers are typically metal. Other metal-based chamber components can include, but are not limited to, index plates, substrate supports, showerheads, focus rings, lift pins, chamber ceilings, chamber floors, and other components within the processing chamber, if any.

[0002] Prior to processing substrates, the processing chamber and components therein can be coated with one or more films. This coating process is done while no substrate is present in the processing chamber. The deposited film(s) act to prevent degradation of the coated chamber components during subsequent processing steps, which also results in minimizing contamination on the substrates. Without any such coating on the chamber components, the processing conditions experienced while processing substrates could degrade the metal surfaces of the various chamber components, resulting in metallic contamination on the substrate, which is highly undesirable.

[0003] The background description provided herein is for the purposes of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure. SUMMARY

[0004] Various examples herein relate to methods for preparing a semiconductor processing apparatus for processing substrates, and the related apparatus and systems for performing the methods. In one aspect of the examples herein, a method of preparing a semiconductor processing apparatus for processing substrates is provided, the method including: depositing a precoat on exposed surfaces within a processing chamber of the semiconductor processingAttorney Docket No. LAM1P025WO-11824-1WO apparatus, where the precoat includes a doped carbon film, and where the precoat is deposited on the exposed surfaces within the processing chamber in the absence of a substrate in the processing chamber.

[0005] In some examples, the semiconductor processing apparatus is configured to deposit a carbon-based material on the substrates. In some such cases, the carbon-based material is an ashable hardmask material.

[0006] In some examples, the precoat includes carbon and a dopant, and the dopant is selected from at least one of lithium, sodium, beryllium, magnesium, boron, aluminum, gallium, indium, silicon, germanium, tin, nitrogen, phosphorus, arsenic, antimony, bismuth, sulfur, selenium, tellurium, fluorine, chlorine, bromine, iodine, chromium, zinc, and gold. In various examples, the dopant includes silicon.

[0007] The precoat may be deposited on various exposed surfaces in the processing chamber. In some examples, the exposed surfaces within the processing chamber include an index plate, and the precoat is deposited on the index plate.

[0008] In various examples, the doped carbon film of the precoat reduces a degree to which a substrate slips on the index plate while the substrate is being transferred between a first station and a second station positioned within the processing chamber.

[0009] In some cases, the method further includes depositing an undercoat on bare metal surfaces exposed within the processing chamber prior to depositing the precoat, where the precoat is deposited on the undercoat, and where both the undercoat and the precoat are deposited on the index plate. In these or other cases, the method may further include processing one or more substrates in the processing chamber while the precoat is present, where processing the one or more substrates includes transferring at least one substrate from a first station to a second station, the first station and second station each being positioned within the processing chamber.

[0010] The precoat may have particular properties. In some cases, the precoat includes silicon- doped carbon having a composition ranging from about 0.01 wt% silicon to about 40 wt% silicon, and ranging from about 20 wt% carbon to about 70 wt% carbon. In some cases, the precoat does not include nitrogen. In these or other cases, the precoat may have a hardness ranging from about 1 GPa to about 15 GPa.

[0011] While many deposition methods may be used, in various examples the precoat is deposited via plasma enhanced chemical vapor deposition. In some such cases, the precoat includes silicon-doped carbon, and depositing the precoat includes flowing a carbon- containing reactant to the processing chamber, flowing a silicon-containing reactant to the processing chamber, and generating plasma to drive a reaction between the carbon-containingAttorney Docket No. LAM1P025WO-11824-1WO reactant and the silicon-containing reactant to produce the silicon-doped carbon. The carbon- containing reactant may include a hydrocarbon and the silicon-containing reactant may include a silane. For instance, in some cases the carbon-containing reactant includes C2H2 and the silicon-containing reactant includes SiH4.

[0012] In another aspect of the disclosed examples, an apparatus for processing substrates is provided, the apparatus including: a processing chamber; two or more stations in the processing chamber, each station configured to process one of the substrates; an index plate positioned in the processing chamber and configured to transfer substrates from one station to another within the processing chamber; and a controller configured to cause depositing a precoat on exposed surfaces within the processing chamber, including on the index plate, where the precoat includes a doped carbon film, and where the precoat is deposited on the exposed surfaces within the processing chamber in the absence of a substrate in the processing chamber.

[0013] In some examples, the apparatus is configured to deposit a carbon-based material on the substrates. For instance, the carbon-based material may be an ashable hardmask material.

[0014] In various examples, the precoat includes carbon and a dopant, and the dopant is selected from at least one of lithium, sodium, beryllium, magnesium, boron, aluminum, gallium, indium, silicon, germanium, tin, nitrogen, phosphorus, arsenic, antimony, bismuth, sulfur, selenium, tellurium, fluorine, chlorine, bromine, iodine, chromium, zinc, and gold. In certain cases, the dopant includes silicon.

[0015] These and other aspects are described further below with reference to the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG. 1 is a flowchart illustrating a method of processing a batch of substrates in a processing chamber according to various examples.

[0017] FIGS. 2A-2C depict a portion of a processing chamber as a group of two substrates are transferred among different stations within the processing chamber.

[0018] FIGS.3A-3C are similar to FIGS.2A-2C, but further illustrate a common misalignment problem that can occur when the substrates are transferred among the different stations.

[0019] FIG. 4 depicts one of the stations from FIG. 3C in greater detail, showing that the substrate is offset from its intended position.

[0020] FIG.5 shows a close-up cross-sectional view of a portion of an index plate coated in an undercoat and a precoat, with a substrate positioned thereon.

[0021] FIG. 6 is a flowchart illustrating a method of forming a precoat according to various examples herein.

[0022] FIG. 7 depicts a station configured to perform vapor deposition processes according toAttorney Docket No. LAM1P025WO-11824-1WO certain examples herein.

[0023] FIG. 8 shows an apparatus configured to perform vapor deposition processes according to various examples herein, where the apparatus includes a processing chamber having four stations.

[0024] FIGS.9A-9C depict experimental results according to certain examples herein. DETAILED DESCRIPTION

[0025] In the following description, numerous specific details are set forth to provide a thorough understanding of the presented examples. The disclosed examples may be practiced without some or all of these specific details. In other instances, well-known process operations have not been described in detail to not unnecessarily obscure the disclosed examples. While the disclosed examples will be described in conjunction with the specific examples, it will be understood that it is not intended to limit the disclosed examples.

[0026] The apparatuses used to fabricate semiconductor devices typically include one or more processing chamber configured to hold one or more substrate. Each processing chamber can include one or more stations, each station configured to hold and process a substrate. These processing chambers are typically fabricated from metal such as aluminum and alloys thereof. The processing chamber often includes a number of components therein configured for various purposes. These components can include, but are not limited to, index plates, robot arms, and other components for moving substrates within the apparatus, substrate supports (also referred to as substrate holders, pedestals, chucks, etc.), showerheads and other reactant delivery systems, focus rings, lift pins, etc. Any of these components may be made of metal or a metal- containing material.

[0027] If the metal chamber components are left bare, they are vulnerable to degradation during substrate processing, especially when such processing involves exposure to harsh conditions such as plasma. This degradation is problematic both because it damages the apparatus, and because the metallic particles that are removed from the chamber components are re-deposited on substrates as unwanted contamination.

[0028] To prevent these problems, the processing chamber and components therein are typically coated with one or more films prior to processing substrates. In many cases, this involves depositing both an undercoat and a precoat. As used herein, an undercoat is a film that is formed in direct contact with a metal surface of a chamber component. In many examples herein, the undercoat is a silicon oxide film. By contrast, as used herein, a precoat is a film that is deposited on chamber components after forming the undercoat (often in direct contact with the undercoat) and prior to using the coated chamber component for processing substrates. When the apparatus is used to deposit film on substrates, the precoat film typically has theAttorney Docket No. LAM1P025WO-11824-1WO same or similar composition as the film being deposited on the substrates. Both the undercoat and the precoat are formed on the surfaces of the chamber components that are exposed within the reaction chamber. As noted above, the coated surfaces can include the chamber walls, chamber ceilings, chamber floors, substrate supports, focus rings, index plates, showerheads, lift pins, etc.

[0029] Various examples herein are presented in the context of an apparatus used to deposit carbon-based film on substrates. For instance, the carbon-based film may be an ashable hardmask film. Such films are commonly used in logic applications, memory applications, etc. Other types of carbon-based deposition are also envisioned. Because such apparatuses are used for depositing carbon-based film on substrates, the precoat used in connection with such apparatuses is also a carbon-based film. In many examples herein, the precoat is a carbon- based film including one or more additional elements referred to as dopants. The dopant is often provided during formation of the carbon-based precoat.

[0030] The process of forming the undercoat and precoat is done while no substrate is present in the processing chamber, and it can be repeated at any desired frequency. As shown in FIG. 1, the coating process is cycled with substrate processing steps and chamber cleaning steps to ensure that the processing chamber and components therein remain in good condition and any film buildup on relevant surfaces does not become too severe. The cycle begins with operation 101, where the undercoat is deposited on bare chamber surfaces. Next, the precoat is deposited on the undercoat in operation 103. Next, at operation 105 a series of substrates is processed in the processing chamber, for example to deposit carbon-based film thereon. This deposition also results in additional film buildup on various surfaces of the processing chamber and the components therein. When this buildup approaches an undesirable level, the processing chamber and components therein are subjected to a cleaning process in operation 107 to remove film buildup, including the undercoat and precoat. The cleaning process essentially restores the internal surfaces of the processing chamber and components therein to their bare metal state. This cycle can then be repeated, starting with operation 101, to re-prepare the processing chamber and process additional substrates.

[0031] As used herein, the term “batch” is intended to refer to all substrates processed in a particular apparatus between subsequent cleaning processes in the above-described cycle. With reference to FIG. 1, all of the substrates processed in a particular iteration of operation 105 belong to the same batch (e.g., a first iteration of the method of FIG. 1 processes a first batch of substrates, a second iteration of the method of FIG. 1 processes a second batch of substrates, etc.). Within each batch, substrates may be processed simultaneously and / or serially. For instance, groups of substrates may be processed simultaneously in cases whereAttorney Docket No. LAM1P025WO-11824-1WO the apparatus is configured to process multiple substrates at the same time. Individual substrates and / or groups of substrates can be processed serially in between subsequent cleaning cycles. In other words, for each batch of substrates, the processing chamber is (1) prepared with undercoat / precoat, (2) used to deposit film on substrates, and then (3) cleaned to remove film buildup and undercoat / precoat.

[0032] Unfortunately, certain problems arise when the apparatus is used to deposit carbon-based film on substrates. As mentioned above, in such cases the precoat that is deposited on the chamber components is typically a carbon-based film. This carbon-based film can be relatively slippery. While this slipperiness is not particularly problematic for chamber walls and other chamber components that do not come into contact with the substrate, it can be an issue for substrate supports, index plates, robot arms, and other components that are used for supporting and / or transferring substrates within the processing chamber. As used herein, the term “index plate” is intended to refer to a plate / platform / etc. on which one or more substrate is supported, directly or indirectly, while the substrate(s) are being transferred among different stations in a processing chamber. In some cases, an index plate may also be referred to as a transfer plate, a spindle, or a spindle index. Example index plates are shown in FIGS.2A-2C and FIGS.3A- 3C, for instance. Index plates are commonly fabricated from the same material used to form the processing chamber (e.g., aluminum in many cases).

[0033] FIGS. 2A-2C present a top-down views of a portion of a processing apparatus 200 used to process semiconductor substrates. The apparatus 200 may be used to deposit carbon-based film such as ashable hardmask, for example using plasma enhanced chemical vapor deposition (PECVD). Alternatively or in addition, the apparatus may be used to deposit other types of film, and / or to perform other types of processing. In this example, the apparatus 200 includes four stations, labeled STN1-STN4, each of which includes a substrate support 202 configured to support a substrate. The substrate supports 202 can take a variety of forms, and may include, e.g., a pedestal, a ring, etc. In many cases, each substrate support 202 is configured to rotate about its central axis during deposition. Each station may include a heater and / or a cooler (not labeled), which may be part of the substrate support 202. The x-axis and y-axis are labeled for the purpose of explanation / illustration. A door 206 for introducing / removing substrates is shown on one side. An index plate 204 is provided to support the substrates as they are rotated between the different stations. FIG. 2A shows Wafer1 (labeled W1) positioned in STN2, Wafer2 (labeled W2) positioned in STN1, and STN3-STN4 with no substrates positioned therein. The index plate 204 is situated such that its legs 205 are positioned between the stations. The configuration shown in FIG. 2A may be used during the first portion of a deposition process, for example, while deposition is ongoing and the substrates are not beingAttorney Docket No. LAM1P025WO-11824-1WO actively transferred between the stations. FIG.2B shows the same apparatus 200 while Wafer1 and Wafer2 are supported on the index plate 204, preparing for substrate rotation / transfer to different stations. The substrates may be lifted before the index plate 204 rotates into place, thereby allowing the legs 205 of the index plate 204 to slide under the substrates. As such, the legs 205 of the index plate 204 are not visible in FIG. 2B. In many cases, the top surface of the index plate 204 directly contacts the back surface of the substrates. In other cases, however, the top surface of the index plate 204 may contact another portion of the apparatus such as a ring, arc, or other structure on which a substrate is positioned in each station.

[0034] FIG.2C shows apparatus 200 after Wafer1 and Wafer2 have been rotated / transferred to STN4 and STN3, respectively. After Wafer1 and Wafer2 reach their new stations, the index plate 204 again slides into place such that its legs 205 extend between the stations, and the substrates are lowered onto the substrate supports 202. The configuration shown in FIG. 2C may be used during a second portion of the deposition process, for example, after the substrates have been transferred between stations. The substrates may be rotated among the different stations over the course of deposition, as shown in FIGS.2A-2C, for example to combat film non-uniformities that might otherwise be problematic.

[0035] FIG. 2C depicts the desired position for Wafer1 and Wafer2 after substrate rotation / transfer between stations. In the desired position, the substrates are centered on their substrate supports 202. Unfortunately, because of the slippery nature of the carbon-based film sometimes used for the precoat, the substrates frequently deviate from this desired position. FIGS. 3A-3C illustrate this problem. FIGS. 3A and 3B are analogous to FIGS. 2A and 2B, and for the sake of brevity the description will not be repeated. FIG. 3C shows that after substrate rotation / transfer, Wafer1 and Wafer2 are each offset in both the x-direction and the y-direction compared to their desired positions (e.g., Wafer1 is offset in the +x direction and the +y direction, while Wafer2 is offset in the -x direction and +y direction). These offsets arise due to the centrifugal forces exerted on the substrates during rotation / transfer.

[0036] FIG. 4 illustrates the problem shown in FIG. 3C in greater detail. In particular, FIG. 4 shows Wafer2 in STN3 from FIG.3C. Point 208 relates to the center of Wafer2, while point 210 relates to the center of the substrate support 202. Point 208 and point 210 should be at the same position such that the substrate is centered on the substrate support 202. However, it can be seen that point 208 is offset from point 210 with respect to both the x and y directions. This offset can be referred to as the wafer center shift offset. When considering a batch of substrates processed on a particular apparatus between subsequent chamber cleaning processes, this wafer center shift offset measurement can be averaged over all wafers in the batch, such that the batch has its own average wafer center shift offset (also referred to as the AWC shift offset,Attorney Docket No. LAM1P025WO-11824-1WO or more simply the AWC). It is desirable for the wafer center shift offset, the average wafer center shift offset, and the variation on the wafer center shift offset to be as low as possible.

[0037] The offset shown in FIGS. 3C and 4 is undesirable at least because (1) the substrates should be centered on the substrate supports for desired film and uniformity performance, and (2) the substrates can become contaminated with unwanted particles in cases where the substrate slips sufficiently far to contact other chamber components (e.g., rings, chamber walls, etc.). While the offset can be reduced by rotating the index plate more slowly, in many cases there is a minimum rotation rate at which the index plate moves, and this minimum rotation rate is often fast enough that slippage is still observed. At lower rotation rates, substrate throughput can be severely compromised.

[0038] It has been found that this offset can be reduced by adjusting the composition of the carbon-based precoat to include a dopant. In various examples herein, the dopant is silicon, but other dopants may be used alternatively or in addition to silicon, as discussed further below. In various examples the precoat includes hydrogen in addition to the carbon and dopant, which may originate from a carbon-containing reactant used to form the precoat.

[0039] While the precoat is formed on most or all of the surfaces exposed within the processing chamber, the most relevant surface for purposes of the examples herein is the upper surface of the index plate, because the substrates are supported on this surface during rotation between stations. While much of the description herein focuses on the index plate and the precoat formed thereon, it is understood that the precoat is also typically present on other internal chamber surfaces and various components within the processing chamber, as mentioned above.

[0040] FIG.5 depicts a close-up cross-sectional view of a portion of an index plate 500 having a metal base 501, with undercoat 502 and precoat 503 formed thereon, in accordance with various examples herein. A substrate 504 is placed on top of the index plate 500. Example metals for the metal base 501 are listed above. The undercoat 502 is typically silicon oxide (e.g., SiO2) but may also be another material. The precoat 503 is a doped carbon film, as described herein. While the undercoat 502 and precoat 503 may each be formed through any deposition methods, plasma enhanced chemical vapor deposition is typically used for speed and quality purposes.

[0041] FIGS.2A-2C and 3A-3C depict an example of an index plate 204, which may be covered by an undercoat 502 and / or precoat 503 as shown in FIG.5. The index plate 204 is shaped to include legs 205 that extend radially outward from a center area. The legs 205 support a substrate during transfer between stations. The metal base 501 that forms the index plate may have particular dimensions, and may be designed to alternately (i) fit between stations as shown in FIGS.2A, 2C, 3A, and 3C, and (ii) fit under the substrates to support the substrates duringAttorney Docket No. LAM1P025WO-11824-1WO transfer, as shown in FIGS.2B and 3B. The design / dimensions of the index plate are selected to achieve these purposes. In some cases, the metal base 501 that forms the legs 205 of the index plate 204 may have a particular thickness (for FIG.2A, this thickness is measured into- the-page), for example ranging from about 3 mm to about 10 mm. Example thicknesses for the undercoat 502 and precoat 503 are provided below. Further, the legs 205 may have a particular length (for FIG. 2A, this length is measured in the x-direction for the two legs that extend along this axis or in the y-direction for the two legs that extend along this axis) that extends from the center of the index plate 204 to the farthest tip of the leg 205. This length should be sufficiently long to support the substrate during transfer, and sufficiently short to ensure that the leg 205 does not experience unwanted contact with other chamber components such as chamber walls, etc. during substrate transfer. In addition, the legs 205 may have a particular width (for FIG. 2A, this width is measured in the y-direction for the two legs that extend along the x-axis, and measured in the x-direction for the two legs that extend along the y-axis). This width should be sufficiently wide to adequately support the substrate during transfer, and should be sufficiently thin, at all portions, to fit between the substrates / stations without negatively impacting deposition or other processing that occurs in the stations when processing substrates. As shown in FIG.2A, for example, in many cases the width of the legs 205 varies along the length of the legs 205.

[0042] A variety of dopants may be used for the doped carbon precoat. A single dopant may be used, or a combination of dopants may be used. In many cases, the dopant is an element other than hydrogen. Hydrogen may be present in the carbon-based film (e.g., being introduced from a hydrocarbon-based reactant and / or H2used to form the precoat), but is not considered to be a dopant for purposes herein. Additional elements such as oxygen may also be present in the precoat film. In some examples, one or more dopant is a p-type dopant, sometimes referred to as an acceptor. In some examples, one or more dopant is an n-type dopant, sometimes referred to as a donor. Example dopants include, but are not limited, to, group 1 elements such as lithium and sodium, group 2 elements such as beryllium and magnesium, group 13 elements such as boron, aluminum, gallium, and indium, group 14 elements such as silicon, germanium, and tin, group 15 elements such as nitrogen, phosphorus, arsenic, antimony, and bismuth, group 16 elements such as sulfur, selenium, and tellurium, and group 17 elements such as fluorine, chlorine, bromine, and iodine. In some cases, one or more dopants may be a transition metal element such as chromium, zinc, or gold. In various examples, one or more dopants may be an alkali metal, an alkaline earth metal, a transition metal, a post-transition metal, a metalloid, a nonmetal, or a halogen. In some examples, the precoat does not include metals or halogens. In some examples, the precoat does not includeAttorney Docket No. LAM1P025WO-11824-1WO nitrogen. It is understood that a precoat that “does not include” a particular element or type of element may in fact include such an element or type of element at a trace amount; however, such elements are not intentionally provided during formation of the precoat. In some examples, the precoat includes two or more dopants, one of which is silicon.

[0043] In some cases, the precoat may have a particular composition. For example, the precoat may have a minimum carbon content and / or a maximum carbon content. Similarly, the precoat may have a minimum dopant content and / or a maximum dopant content. In these or other cases, the precoat may have a minimum hydrogen content and / or a maximum hydrogen content. The precoat may also have a minimum and / or maximum oxygen content. As used herein, these contents are listed with respect to weight%, unless otherwise noted.

[0044] In various examples, the following minima and / or maxima may be used for the composition of the precoat. These minima and maxima can be combined as desired for a particular application (e.g., any minimum can be combined with any maximum to set a range for the relevant element, and the minima / maxima / ranges for the different elements can be combined as desired for the relevant precoat film). In some cases, the minimum carbon content may be about 20%, for example about 30%, or about 40%, or about 50%, or about 60%. In these or other examples, the maximum carbon content may be about 30%, or about 40%, or about 50%, or about 60%, or about 70%. In these or other examples, the minimum dopant content may be about 0.01%, for example about 0.1%, or about 0.5%, or about 1%, or about 2%, or about 5%, or about 10%, or about 15%, or about 20%, or about 25%, or about 30%, or about 35%. In these or other examples, the maximum dopant content may be about 0.5%, or about 1%, or about 5%, or about 10%, or about 15%, or about 20%, or about 25%, or about 30%, or about 35%, or about 40%, or about 50%. These dopant contents may correspond to a single dopant among several, or to all total dopants in the precoat. In these or other examples, the minimum hydrogen content may be about 20%, for example about 30%, or about 40%. In these or other examples, the maximum hydrogen content may be about 30%, or about 40%, or about 50%. In various examples, the minimum oxygen content may be about 0.1%, or about 0.5%, or about 1%, or about 2%. In these or other examples, the maximum oxygen content may be about 1%, or about 2%, or about 5%. In some cases, oxygen is not included in the precoat, or is included in only trace amounts.

[0045] In certain examples, the precoat may have particular properties, as-deposited. Such properties may include, e.g., density, hardness, modulus, refractive index, extinction coefficient, stress, etc. In some cases, the precoat may have a minimum density of about 1 g / cm3, or about 1.5 g / cm3. In these or other cases, the precoat may have a maximum density of about 2 g / cm3. In these or other cases, the precoat may have a minimum hardness of aboutAttorney Docket No. LAM1P025WO-11824-1WO 1 GPa, or about 5 GPa, or about 10 GPa. In these or other cases, the precoat may have a maximum hardness of about 10 GPa, or about 15 GPa. In these or other cases, the precoat may have a minimum Young’s modulus of about 5 GPa, or about 10 GPa, or about 25 GPa, or about 50 GPa. In these or other cases, the precoat may have a maximum Young’s modulus of about 10 GPa, or about 25 GPa, or about 50 GPa, or about 80 GPa. In some examples, the precoat may have a minimum refractive index at 633 nm of about 1.2. In these or other cases, the precoat may have a maximum refractive index at 633 nm of about 2.4. In some examples, the precoat may have a minimum extinction coefficient at 633 nm of about 0, or about 0.01, or about 0.1. In these or other cases, the precoat may have a maximum extinction coefficient at 633 nm of about 1.0. In some examples, the precoat may have a stress ranging from about - 1000MPa to about +200 MPa.

[0046] The precoat may have a particular thickness in some examples. For instance, the precoat may have a minimum thickness of about 0.5 μm, or about 1 μm, or about 2 μm. In these or other cases, the precoat may have a maximum thickness of about 2 μm, or about 3 μm. The undercoat may also have a particular thickness. For instance, the undercoat may have a minimum thickness of about 1 μm, or about 2 μm, or about 3 μm. In these or other examples, the undercoat may have a maximum thickness of about 2 μm , or about 5 μm, or about 6 μm. In some cases, the precoat is thicker than the undercoat. In other cases, the undercoat is thicker than the precoat. In some cases, the undercoat and the precoat are the same or substantially the same thickness, for example within about 15% of one another.

[0047] The undercoat and / or precoat thickness may vary among different portions of the apparatus. For instance, some exposed surfaces within the processing chamber may receive a relatively thicker coat, and other exposed surfaces may receive a relatively thinner coat. The undercoat and precoat thicknesses listed above may correspond to the average thickness of such films as deposited on an index plate or similar transfer hardware used to transfer one or more substrate within the processing chamber.

[0048] The precoat typically has a structure that is amorphous.

[0049] In most cases the undercoat and precoat are deposited in separate reactions in order to sufficiently control the relevant reactants / reactions. For instance, the reaction chamber may be purged and / or evacuated after deposition of the undercoat and prior to deposition of the precoat to ensure that any excess reactants from undercoat formation are unable to interact with reactants used to form the precoat. In some cases, however, the undercoat and precoat deposition processes could be combined into a single deposition, with the undercoat being deposited first, followed by deposition of the precoat. In some such cases, there may be a gradient in composition between the last-deposited portion of the undercoat and the first-Attorney Docket No. LAM1P025WO-11824-1WO deposited portion of the precoat.

[0050] As noted above, any deposition processes may be used to form the undercoat and precoat. However, in many cases PECVD is used to form one or both of these coatings, as such deposition methods are able to produce relatively high quality film very quickly. Other deposition methods that could be used to form the undercoat and / or precoat include, but are not limited to, chemical vapor deposition (e.g., without plasma), physical vapor deposition, sputtering, pulsed laser deposition, metal organic chemical vapor deposition, atomic layer deposition, plasma enhanced atomic layer deposition, molecular layer deposition, etc.

[0051] FIG.6 presents a flowchart for a method of depositing a doped carbon precoat according to various examples herein. For instance, the method of FIG. 6 may be used to perform operation 103 in FIG.1. The method of FIG.6 begins after the undercoat has been formed on exposed surfaces on the interior of the processing chamber. These exposed surfaces can include, e.g., surfaces of the chamber walls, chamber ceiling, chamber floor, substrate support, focus ring, index plate, etc. The method of FIG.6 begins with operation 601, where a carbon- containing reactant and a dopant-containing reactant are simultaneously provided to the processing chamber. As used herein, two events that occur simultaneously are understood to overlap in time, at least partially. Inert gas (e.g., He, Ar, Ne, Kr, etc.) may also be provided. One or more additional reactants / processing gasses may also be provided. One such example is hydrogen (H2). At operation 603, the processing chamber is exposed to plasma, thereby driving a gas phase reaction between the carbon-containing reactant and the dopant-containing reactant. The resulting material, a silicon-doped carbon, is deposited on exposed surfaces within the processing chamber in operation 605, including on an upper surface of the index plate. In most cases, the carbon-containing reactant and the dopant-containing reactant are distinct reactants. In other cases, a single reactant that includes both carbon and the dopant may be used.

[0052] In a particular example, the method of FIG.6 may be performed by providing a silicon- containing reactant in operation 603 and forming a silicon-doped carbon precoat film in operation 605.

[0053] The following example processing conditions may be used for forming the precoat, according to various examples herein. Such processing conditions can be combined as desired for a particular application. The minimum flow rate for the carbon-containing reactant may be about 100 sccm, or about 500 sccm, or about 1000 sccm, or about 2500 sccm. The maximum flow rate for the carbon-containing reactant may be about 500 sccm, or about 1000 sccm, or about 2500 sccm, or about 5000 sccm. The minimum flow rate for the dopant-containing reactant may be about 50 sccm, or about 100 sccm, or about 200 sccm, or about 400 sccm.Attorney Docket No. LAM1P025WO-11824-1WO The maximum flow rate for the dopant-containing reactant may be about 100 sccm, or about 250 sccm, or about 500 sccm. In some cases the ratio between the flow of the dopant- containing reactant and the flow of the carbon-containing reactant may be within a particular range. For instance, the minimum ratio between the flow of the dopant-containing reactant and the flow of the carbon-containing reactant (FlowDopantReactant:FlowCReactant) may be about 0.01:1, or about 0.1:1, or about 0.2:1. The maximum ratio between the flow of the dopant- containing reactant and the flow of the carbon-containing reactant may be about 0.1:1, or about 0.5:1, or about 1:1. The minimum flow rate for the inert gas, when provided, may be about 1000 sccm, or about 5000 sccm. The maximum flow rate for the inert gas may be about 10,000 sccm, or about 20,000 sccm. The minimum flow rate for the hydrogen (H2), when provided, may be about 1000 sccm, or about 5000 sccm. The maximum flow rate for the hydrogen may be about 10,000 sccm, or about 20,000 sccm.

[0054] The temperature in the processing chamber during formation of the precoat may be maintained in a range that includes a minimum temperature of about 200°C, or about 400°C, and a maximum temperature of about 500°C, or about 650°C. The pressure in the processing chamber may also be controlled during formation of the precoat. The minimum pressure in the processing chamber may be about 0.8 Torr, or about 1 Torr, or about 2 Torr. In these or other examples, the maximum pressure in the processing chamber may be about 3 Torr, or about 5 Torr.

[0055] The plasma may be generated using particular parameters in some cases, including both high frequency (HF) and low frequency (LF) power. For instance, the minimum HF power used to generate the plasma may be about 50 W, or about 100 W, or about 1000 W. The maximum HF power used to generate the plasma may be about 500 W, or about 1000 W, or about 2000 W. The minimum LF power used to generate the plasma may be about 50 W, or about 100 W, or about 1000 W. The maximum LF power used to generate the plasma may be about 500 W, or about 1000 W, or about 2000 W. In many examples, the plasma is an inductively coupled plasma. Other types of plasma may be used alternatively or in addition to the inductively coupled plasma. The frequency used to generate the plasma may be 13.56MHz or 27.13MHz for high frequency, and 400kHz to 40MHz for low frequency.

[0056] The example processing conditions provided herein are appropriate for forming a precoat in a processing chamber configured to simultaneously process up to four 300 mm diameter substrates in four stations (as shown in FIG. 8, described further below), and can be scaled accordingly for processing chambers of other sizes.

[0057] The examples herein are not limited to any particular reactants. Generally, any reactants that include the relevant elements and are compatible with the relevant processing conditionsAttorney Docket No. LAM1P025WO-11824-1WO and apparatus materials can be used. In some cases, the reactants that are used do not include metals and / or halogens. In many cases the carbon-containing reactant is a hydrocarbon, for example an alkene, an alkane, an alkyne, etc. The number of carbon atoms in the carbon- containing reactant may be 1, 2, 3, 4, 5, 6, 7, 8, etc. Example carbon-containing reactants include, but are not limited to, Methane (CH4), Ethane (C2H6), Propane (C3H8), Butane (C4H10), Pentane (C5H12), Hexane (C6H14), Heptane (C7H16), Octane (C8H18), Ethene (C2H4), Propene (C3H6), Butene (C4H8), Pentene (C5H10), Hexene (C6H12), Heptene (C7H14), Octene (C8H16), Ethyne (C2H2), Propyne (C3H4), Butyne (C4H6), Pentyne (C5H8), Hexyne (C6H10), Septyne (C7H12), Octyne (C8H14), etc. Substituted versions may be used in some cases.

[0058] Example dopant elements are listed above. The dopant-containing reactant may include one or more of such dopant atoms. For instance, where the dopant is silicon, the dopant- containing reactant is a silicon-containing reactant. Similarly, where the dopant is germanium, the dopant-containing reactant is a germanium-containing reactant.

[0059] In various examples where the dopant is silicon, the dopant-containing reactant may be a silane, a siloxane, a silazene, a silanol, etc. Substituted versions of such reactants may also be used. Example silicon-containing reactants include, but are not limited to, silane (SiH4), Bis(dimethylamino)dimethylsilane ([N(CH3)2]2(CH3)2Si), Hexamethyldisiloxane ((CH3)3SiOSi(CH3)3), Bis(ethylmethylamino)silane ((C2H5CH3N)2SiH2), 3- Aminopropyltriethoxysilane (H2N(CH2)3Si(OC2H5)3), 3-Aminopropyltriethoxysilane (H2N(CH2)3Si(OC2H5)3), Bis(t-butylamino)silane ([NH(C4H9)]2SiH2), Bis(diethylamino)silane (SiH2[N(CH2CH3)2]2), Hexakis(ethylamino)disilane ((C2H5NH)6Si2), 2,2,4,4,6,6-Hexamethylcyclotrisilazane (C6H21N3Si3), Silicon(IV) bromide (SiBr4), Silicon(IV) chloride (SiCl4), Tetrabutoxysilane (Si(OC4H9)4), Tetraethoxysilane (Si(OC2H5)4), Tetrakis(ethylmethylamino)silane ([CH3(CH2CH2)N]4Si), Tetramethoxysilane (Si(OCH3)4), 1,1,3,3-Tetramethyldisiloxane (C4H14OSi2), Tetramethylsilane (Si(CH3)4), Tri-t-butoxysilanol ([(CH3)3CO]3SiOH), Trimethylsilane ((CH3)3SiH), Tri-t-pentoxysilanol ([CH3CH2C(CH3)2O]3SiOH), Tris(dimethylamino)silane ([(CH3)2N]3SiH), etc. As mentioned, other kinds of dopant-containing reactants can be used when the dopant is an element other than silicon.

[0060] As noted above, the undercoat is typically a silicon oxide material such as SiO2, which may be deposited via PECVD. However, the examples herein can be practiced with other types of undercoats, or even without any undercoat. For instance, the method of FIG.1 can be modified such that (1) the undercoat deposition of operation 101 is omitted, (2) the precoat is deposited on bare chamber surfaces in operation 103, and (3) the chamber cleaning in operation 107 cycles back to precoat deposition in operation 103. Omitting the undercoat could lead toAttorney Docket No. LAM1P025WO-11824-1WO other processing problems; however, the undercoat is not strictly required to achieve the benefits described herein related to the doped carbon precoat, particularly those benefits associated with reduced substrate slippage on the index plate during substrate transfer between stations. APPARATUS

[0061] The examples herein can be practiced on many different types of apparatus. In many cases, the apparatus is a deposition apparatus configured to deposit carbon (e.g., ashable hardmask in some examples) via CVD or ALD, either or which may be plasma enhanced. However, the techniques herein can similarly be used for other types of semiconductor processing apparatus including other types of deposition apparatus (or deposition apparatus configured to deposit other types of film), etch apparatus, plasma or heat treatment apparatus, photolithography apparatus, substrate cleaning apparatus, etc. The described techniques are particularly useful in apparatuses having an index plate, robot arm, or similar substrate transfer component that transfers substrates within the processing chamber, especially when such transfer occurs between stations in a single processing chamber.

[0062] FIG. 7 schematically shows an example of a process station 700 that may be used to deposit material using atomic layer deposition (ALD) and / or chemical vapor deposition (CVD), either of which may be plasma enhanced. With reference to FIGS.2A-2C and FIGS. 3A-3C, each of STN1-STN4 may be implemented as shown in relation to process station 700.

[0063] For simplicity, the process station 700 is depicted as a standalone process station having a process chamber body 702 for maintaining a low-pressure environment. However, it will be appreciated that a plurality of process stations 700 may be included in a common process tool environment, as shown in FIGS.2A-2C and FIGS.3A-3C. Further, it will be appreciated that, in some examples, one or more hardware parameters of process station 700, including those discussed in detail below, may be adjusted programmatically by one or more computer controllers.

[0064] Process station 700 fluidly communicates with reactant delivery system 701 for delivering process gases to a showerhead 706. Reactant delivery system 701 includes a mixing vessel 704 for blending and / or conditioning process gases for delivery to showerhead 706. One or more mixing vessel inlet valves 720 may control introduction of process gases to mixing vessel 704. Similarly, a showerhead inlet valve 705 may control introduction of process gasses to the showerhead 706.

[0065] Some reactants may be stored in liquid form prior to vaporization at and subsequent delivery to the process station. For example, the example of FIG. 7 includes a vaporizationAttorney Docket No. LAM1P025WO-11824-1WO point 703 for vaporizing liquid reactant to be supplied to mixing vessel 704. In some examples, vaporization point 703 may be a heated vaporizer. The reactant vapor produced from such vaporizers may condense in downstream delivery piping. Exposure of incompatible gases to the condensed reactant may create small particles. These small particles may clog piping, impede valve operation, contaminate substrates, etc. Some approaches to addressing these issues involve sweeping and / or evacuating the delivery piping to remove residual reactant. However, sweeping the delivery piping may increase process station cycle time, degrading process station throughput. Thus, in some examples, delivery piping downstream of vaporization point 703 may be heat traced. In some examples, mixing vessel 704 may also be heat traced. In one non-limiting example, piping downstream of vaporization point 703 has an increasing temperature profile extending from approximately 100°C to approximately 150°C at mixing vessel 704.

[0066] In some examples, reactant liquid may be vaporized at a liquid injector. For example, a liquid injector may inject pulses of a liquid reactant into a carrier gas stream upstream of the mixing vessel. In one scenario, a liquid injector may vaporize reactant by flashing the liquid from a higher pressure to a lower pressure. In another scenario, a liquid injector may atomize the liquid into dispersed microdroplets that are subsequently vaporized in a heated delivery pipe. It will be appreciated that smaller droplets may vaporize faster than larger droplets, reducing a delay between liquid injection and complete vaporization. Faster vaporization may reduce a length of piping downstream from vaporization point 703. In one scenario, a liquid injector may be mounted directly to mixing vessel 704. In another scenario, a liquid injector may be mounted directly to showerhead 706.

[0067] In some examples, a liquid flow controller upstream of vaporization point 703 may be provided for controlling a mass flow of liquid for vaporization and delivery to process station 700. For example, the liquid flow controller (LFC) may include a thermal mass flow meter (MFM) located downstream of the LFC. A plunger valve of the LFC may then be adjusted responsive to feedback control signals provided by a proportional-integral-derivative (PID) controller in electrical communication with the MFM. However, it may take one second or more to stabilize liquid flow using feedback control. This may extend a time for dosing a liquid reactant. Thus, in some examples, the LFC may be dynamically switched between a feedback control mode and a direct control mode. In some examples, the LFC may be dynamically switched from a feedback control mode to a direct control mode by disabling a sense tube of the LFC and the PID controller.

[0068] Showerhead 706 distributes process gases toward substrate 712. In the example shown in FIG.7, substrate 712 is located beneath showerhead 706, and is shown resting on a pedestalAttorney Docket No. LAM1P025WO-11824-1WO 708. It will be appreciated that showerhead 706 may have any suitable shape, and may have any suitable number and arrangement of ports for distributing processes gases to substrate 712.

[0069] In some examples, a microvolume 707 is located beneath showerhead 706. Performing an ALD and / or CVD process in a microvolume rather than in the entire volume of a process station may reduce reactant exposure and sweep times, may reduce times for altering process conditions (e.g., pressure, temperature, etc.), may limit an exposure of process station robotics to process gases, etc. Example microvolume sizes include, but are not limited to, volumes ranging from about 0.1 liter to about 2 liters. This microvolume also impacts productivity throughput. While deposition rate per cycle drops, the cycle time also simultaneously reduces. In certain cases, the effect of the latter is dramatic enough to improve overall throughput of the module for a given target thickness of film.

[0070] In some examples, pedestal 708 may be raised or lowered to expose substrate 712 to microvolume 707 and / or to vary a volume of microvolume 707. For example, in a substrate transfer phase, pedestal 708 may be lowered to allow substrate 712 to be loaded onto pedestal 708. During a deposition process phase, pedestal 708 may be raised to position substrate 712 within microvolume 707. In some examples, microvolume 707 may completely enclose substrate 712 as well as a portion of pedestal 708 to create a region of high flow impedance during a deposition process.

[0071] Optionally, pedestal 708 may be lowered and / or raised during portions the deposition process to modulate process pressure, reactant concentration, etc., within microvolume 707. In one scenario where process chamber body 702 remains at a base pressure during the deposition process, lowering pedestal 708 may allow microvolume 707 to be evacuated. Example ratios of microvolume to process chamber volume include, but are not limited to, volume ratios ranging from about 1:700 to about 1:10. It will be appreciated that, in some examples, pedestal height may be adjusted programmatically by a suitable computer controller.

[0072] In another scenario, adjusting a height of pedestal 708 may allow a plasma density to be varied during plasma activation and / or treatment cycles included in the deposition process. At the conclusion of the deposition process phase, pedestal 708 may be lowered during another substrate transfer phase to allow removal of substrate 712 from pedestal 708.

[0073] While the example microvolume variations described herein refer to a height-adjustable pedestal, it will be appreciated that, in some examples, a position of showerhead 706 may be adjusted relative to pedestal 708 to vary a volume of microvolume 707. Further, it will be appreciated that a vertical position of pedestal 708 and / or showerhead 706 may be varied by any suitable mechanism within the scope of the present disclosure. In some examples, pedestal 708 may include a rotational axis for rotating an orientation of substrate 712. It will beAttorney Docket No. LAM1P025WO-11824-1WO appreciated that, in some examples, one or more of these example adjustments may be performed programmatically by one or more suitable computer controllers.

[0074] Returning to the example shown in FIG.7, showerhead 706 and pedestal 708 electrically communicate with RF power supply 714 and matching network 716 for powering a plasma. In some examples, the plasma energy may be controlled by controlling one or more of a process station pressure, a gas concentration, an RF source power, an RF source frequency, and a plasma power pulse timing. For example, RF power supply 714 and matching network 716 may be operated at any suitable power to form a plasma having a desired composition of radical species. Examples of suitable powers are included above. Likewise, RF power supply 714 may provide RF power of any suitable frequency. In some examples, RF power supply 714 may be configured to control high- and low-frequency RF power sources independently of one another. Example low-frequency RF frequencies may include, but are not limited to, frequencies ranging from about 50 kHz to about 700 kHz. Example high-frequency RF frequencies may include, but are not limited to, frequencies ranging from about 1.8 MHz to about 2.45 GHz. It will be appreciated that any suitable parameters may be modulated discretely or continuously to provide plasma energy for the surface reactions. In one non- limiting example, the plasma power may be intermittently pulsed to reduce ion bombardment with the substrate surface relative to continuously powered plasmas.

[0075] In some examples, the plasma may be monitored in-situ by one or more plasma monitors. In one scenario, plasma power may be monitored by one or more voltage, current sensors (e.g., VI probes). In another scenario, plasma density and / or process gas concentration may be measured by one or more optical emission spectroscopy sensors (OES). In some examples, one or more plasma parameters may be programmatically adjusted based on measurements from such in-situ plasma monitors. For example, an OES sensor may be used in a feedback loop for providing programmatic control of plasma power. It will be appreciated that, in some examples, other monitors may be used to monitor the plasma and other process characteristics. Such monitors may include, but are not limited to, infrared (IR) monitors, acoustic monitors, and pressure transducers.

[0076] In some examples, the plasma may be controlled via input / output control (IOC) sequencing instructions. In one example, the instructions for setting plasma conditions for a plasma process phase may be included in a corresponding plasma activation recipe phase of a deposition process recipe. In some cases, process recipe phases may be sequentially arranged, so that all instructions for a deposition process phase are executed concurrently with that process phase. In some examples, instructions for setting one or more plasma parameters may be included in a recipe phase preceding a plasma process phase. For example, a first recipeAttorney Docket No. LAM1P025WO-11824-1WO phase may include instructions for setting a flow rate of an inert and / or a reactant gas, instructions for setting a plasma generator to a power set point, and time delay instructions for the first recipe phase. A second, subsequent recipe phase may include instructions for enabling the plasma generator and time delay instructions for the second recipe phase. A third recipe phase may include instructions for disabling the plasma generator and time delay instructions for the third recipe phase. It will be appreciated that these recipe phases may be further subdivided and / or iterated in any suitable way within the scope of the present disclosure.

[0077] In some deposition processes, plasma strikes last on the order of a few seconds or more in duration. In certain implementations, much shorter plasma strikes may be used. These may be on the order of 10 ms to 1 second, typically, about 20 to 80 ms, with 50 ms being a specific example. Such very short RF plasma strikes require extremely quick stabilization of the plasma. To accomplish this, the plasma generator may be configured such that the impedance match is set preset to a particular voltage, while the frequency is allowed to float. Conventionally, high-frequency plasmas are generated at an RF frequency at about 13.56 MHz. In various examples disclosed herein, the frequency is allowed to float to a value that is different from this standard value. By permitting the frequency to float while fixing the impedance match to a predetermined voltage, the plasma can stabilize much more quickly, a result which may be important when using the very short plasma strikes associated with some types of deposition cycles.

[0078] In some examples, pedestal 708 may be temperature controlled via heater 710. Further, in some examples, pressure control for process station 700 may be provided by butterfly valve 718. As shown in the example of FIG. 7, butterfly valve 718 throttles a vacuum provided by a downstream vacuum pump (not shown). However, in some examples, pressure control of process station 700 may also be adjusted by varying a flow rate of one or more gases introduced to process station 700.

[0079] FIG.8 shows a schematic view of an example of a multi-station processing tool 800 with an inbound load lock 802 and an outbound load lock 804, either or both of which may comprise a remote plasma source. A robot 806, at atmospheric pressure, is configured to move wafers from a cassette loaded through a pod 808 into inbound load lock 802 via an atmospheric port 810. A wafer is placed by the robot 806 on a pedestal 812 in the inbound load lock 802, the atmospheric port 810 is closed, and the load lock is pumped down. Where the inbound load lock 802 comprises a remote plasma source, the wafer may be exposed to a remote plasma treatment in the load lock prior to being introduced into a processing chamber 814. Further, the wafer also may be heated in the inbound load lock 802 as well, for example, to remove moisture and adsorbed gases. Next, a chamber transport port 816 to processing chamber 814Attorney Docket No. LAM1P025WO-11824-1WO is opened, and another robot (not shown) places the wafer into the reactor on a pedestal of a first station shown in the reactor for processing. While the example depicted in FIG.8 includes load locks, it will be appreciated that, in some examples, direct entry of a wafer into a process station may be provided.

[0080] The depicted processing chamber 814 comprises four process stations, numbered from 1 to 4 in the example shown in FIG. 8. Each station has a heated pedestal (shown at 818 for station 1), and gas line inlets. It will be appreciated that in some examples, each process station may have different or multiple purposes. While the depicted processing chamber 814 comprises four stations, it will be understood that a processing chamber according to the present disclosure may have any suitable number of stations. For example, in some examples, a processing chamber may have five or more stations, while in other examples a processing chamber may have three or fewer stations.

[0081] FIG. 8 also depicts an example of a wafer handling system 890 for transferring wafers within processing chamber 814. In some examples, wafer handling system 890 may transfer wafers between various process stations and / or between a process station and a load lock, for example as described in relation to FIGS.3A-3C. In various examples, wafer handling system 890 includes an index plate as described herein. It will be appreciated that any suitable wafer handling system may be employed. Non-limiting examples also include wafer carousels and wafer handling robots. FIG.8 also depicts an example of a system controller 850 employed to control process conditions and hardware states of process tool 800. System controller 850 may include one or more memory devices 856, one or more mass storage devices 854, and one or more processors 852. Processor 852 may include a CPU or computer, analog and / or digital input / output connections, stepper motor controller boards, etc.

[0082] In some examples, system controller 850 controls all of the activities of process tool 800. System controller 850 executes system control software 858 stored in mass storage device 854, loaded into memory device 856, and executed on processor 852. System control software 858 may include instructions for controlling the timing, mixture of gases, chamber and / or station pressure, chamber and / or station temperature, purge conditions and timing, wafer temperature, RF power levels, RF frequencies, substrate, pedestal, chuck and / or susceptor position, and other parameters of a particular process performed by process tool 800. System control software 858 may be configured in any suitable way. For example, various process tool component subroutines or control objects may be written to control operation of the process tool components necessary to carry out various process tool processes in accordance with the disclosed methods. System control software 858 may be coded in any suitable computer readable programming language.Attorney Docket No. LAM1P025WO-11824-1WO

[0083] In some examples, system control software 858 may include input / output control (IOC) sequencing instructions for controlling the various parameters described above. For example, each phase of a PEALD process may include one or more instructions for execution by system controller 850. The instructions for setting process conditions for a PEALD process phase may be included in a corresponding PEALD recipe phase. In some examples, the PEALD recipe phases may be sequentially arranged, so that all instructions for a PEALD process phase are executed concurrently with that process phase.

[0084] Other computer software and / or programs stored on mass storage device 854 and / or memory device 856 associated with system controller 850 may be employed in some examples. Examples of programs or sections of programs for this purpose include a substrate positioning program, a process gas control program, a pressure control program, a heater control program, and a plasma control program.

[0085] A substrate positioning program may include program code for process tool components that are used to load the substrate onto pedestal 818 and to control the spacing between the substrate and other parts of process tool 800.

[0086] A process gas control program may include code for controlling gas composition and flow rates and optionally for flowing gas into one or more process stations prior to deposition in order to stabilize the pressure in the process station. The process gas control program may include code for controlling gas composition and flow rates within any of the disclosed ranges. A pressure control program may include code for controlling the pressure in the process station by regulating, for example, a throttle valve in the exhaust system of the process station, a gas flow into the process station, etc. The pressure control program may include code for maintaining the pressure in the process station within any of the disclosed pressure ranges.

[0087] A heater control program may include code for controlling the current to a heating unit that is used to heat the substrate. Alternatively, the heater control program may control delivery of a heat transfer gas (such as helium) to the substrate. The heater control program may include instructions to maintain the temperature of the substrate within any of the disclosed ranges.

[0088] A plasma control program may include code for setting RF power levels and frequencies applied to the process electrodes in one or more process stations, for example using any of the RF power levels disclosed herein. The plasma control program may also include code for controlling the duration of each plasma exposure.

[0089] In some examples, there may be a user interface associated with system controller 850. The user interface may include a display screen, graphical software displays of the apparatus and / or process conditions, and user input devices such as pointing devices, keyboards, touch screens, microphones, etc.Attorney Docket No. LAM1P025WO-11824-1WO

[0090] In some examples, parameters adjusted by system controller 850 may relate to process conditions. Non-limiting examples include process gas composition and flow rates, temperature, pressure, plasma conditions (such as RF power levels, frequency, and exposure time), etc. These parameters may be provided to the user in the form of a recipe, which may be entered utilizing the user interface.

[0091] Signals for monitoring the process may be provided by analog and / or digital input connections of system controller 850 from various process tool sensors. The signals for controlling the process may be output on the analog and digital output connections of process tool 800. Non-limiting examples of process tool sensors that may be monitored include mass flow controllers, pressure sensors (such as manometers), thermocouples, etc. Appropriately programmed feedback and control algorithms may be used with data from these sensors to maintain process conditions.

[0092] Any suitable chamber may be used to implement the disclosed examples. Example deposition apparatuses include, but are not limited to, apparatus from the ALTUS®product family, the VECTOR® product family, and / or the SPEED® product family, each available from Lam Research Corp., of Fremont, California, or any of a variety of other commercially available processing systems. Two or more of the stations may perform the same functions. Similarly, two or more stations may perform different functions. Each station can be designed / configured to perform a particular function / method as desired.

[0093] Broadly speaking, the controller may be defined as electronics having various integrated circuits, logic, memory, and / or software that receive instructions, issue instructions, control operation, enable cleaning operations, enable endpoint measurements, and the like. The integrated circuits may include chips in the form of firmware that store program instructions, digital signal processors (DSPs), chips defined as application specific integrated circuits (ASICs), and / or one or more microprocessors, or microcontrollers that execute program instructions (e.g., software). Program instructions may be instructions communicated to the controller in the form of various individual settings (or program files), defining operational parameters for carrying out a particular process on or for a semiconductor wafer or to a system. The operational parameters may, in some examples, be part of a recipe defined by process engineers to accomplish one or more processing steps during the fabrication of one or more layers, materials, metals, oxides, silicon, silicon dioxide, surfaces, circuits, and / or dies of a wafer.

[0094] The controller, in some implementations, may be a part of or coupled to a computer that is integrated with, coupled to the system, otherwise networked to the system, or a combination thereof. For example, the controller may be in the “cloud” or all or a part of a fab host computerAttorney Docket No. LAM1P025WO-11824-1WO system, which can allow for remote access of the wafer processing. The computer may enable remote access to the system to monitor current progress of fabrication operations, examine a history of past fabrication operations, examine trends or performance metrics from a plurality of fabrication operations, to change parameters of current processing, to set processing steps to follow a current processing, or to start a new process. In some examples, a remote computer (e.g. a server) can provide process recipes to a system over a network, which may include a local network or the Internet. The remote computer may include a user interface that enables entry or programming of parameters and / or settings, which are then communicated to the system from the remote computer. In some examples, the controller receives instructions in the form of data, which specify parameters for each of the processing steps to be performed during one or more operations. It should be understood that the parameters may be specific to the type of process to be performed and the type of tool that the controller is configured to interface with or control. Thus as described above, the controller may be distributed, such as by comprising one or more discrete controllers that are networked together and working towards a common purpose, such as the processes and controls described herein. An example of a distributed controller for such purposes would be one or more integrated circuits on a chamber in communication with one or more integrated circuits located remotely (such as at the platform level or as part of a remote computer) that combine to control a process on the chamber.

[0095] Without limitation, example systems may include a plasma etch chamber or module, a deposition chamber or module, a spin-rinse chamber or module, a metal plating chamber or module, a clean chamber or module, a bevel edge etch chamber or module, a physical vapor deposition (PVD) chamber or module, a chemical vapor deposition (CVD) chamber or module, an atomic layer deposition (ALD) chamber or module, an atomic layer etch (ALE) chamber or module, an ion implantation chamber or module, a track chamber or module, and any other semiconductor processing systems that may be associated or used in the fabrication and / or manufacturing of semiconductor wafers.

[0096] As noted above, depending on the process step or steps to be performed by the tool, the controller might communicate with one or more of other tool circuits or modules, other tool components, cluster tools, other tool interfaces, adjacent tools, neighboring tools, tools located throughout a factory, a main computer, another controller, or tools used in material transport that bring containers of wafers to and from tool locations and / or load ports in a semiconductor manufacturing factory.Attorney Docket No. LAM1P025WO-11824-1WO EXPERIMENTAL

[0097] Experimental results have shown that the techniques described herein can be used to reduce substrate slippage / unwanted movement on an index plate during substrate transfer between different stations in a processing chamber, as described in relation to FIGS. 2A-2C, FIGS. 3A-3C, and FIG. 4. FIGS. 9A-9C present experimental results comparing an undoped carbon precoat to a silicon-doped carbon precoat. Specifically, FIG.9A shows the x-axis wafer center shift offset, FIG.9B shows the y-axis wafer center shift offset, and FIG.9C shows the total wafer center shift offset (total wafer center shift offset = ((x-axis wafer center shift offset)2+ (y-axis wafer center shift offset)2)0.5. Each data point shown in FIGS. 9A-9C relates to the shift observed for a single substrate.

[0098] As shown in FIG. 9A, the undoped carbon precoat results in an average x-axis wafer center shift offset of about 0.302 mm, with a standard deviation of about 0.142 mm. By contrast, the silicon-doped carbon precoat shows a smaller average x-axis wafer center shift offset of about 0.299 mm, with a smaller deviation of about 0.068. As shown in FIG.9B, the undoped carbon precoat results in an average y-axis wafer center shift offset of about 0.385 mm, with a standard deviation of about 0.116 mm. By contrast, the silicon-doped carbon precoat shows a smaller average y-axis wafer center shift offset of about 0.294 mm, with a smaller standard deviation of about 0.101 mm. As shown in FIG. 9C, the undoped carbon precoat results in an average total wafer center shift offset of about 0.507 mm, with a standard deviation of about 0.136 mm. By contrast, the silicon-doped carbon precoat shows a smaller average total wafer center shift offset of about 0.431 mm, with a smaller deviation of about 0.076. These are substantial improvements, showing about a 15% reduction in the average total wafer center shift offset, and about a 44% reduction in the standard deviation for this figure. In other words, using a doped carbon precoat can both (1) substantially reduce the degree to which a substrate slips during transfer between stations in a processing chamber, and (2) substantially reduce the variation observed in this slippage. Both of these reductions are beneficial for ensuring that substrates are transferred within the processing chamber in a uniform and repeatable manner.

[0099] In various examples herein, using a doped carbon precoat can result in a maximum average x-axis wafer center shift offset of about 0.3 mm. In these or other examples, the doped carbon precoat can result in a maximum average y-axis wafer center shift offset of about 0.37 mm, or about 0.35 mm, or about 0.30 mm. In these or other examples, the doped carbon precoat can result in a maximum average total wafer center shift offset of about 0.5 mm, or about 0.45 mm, or about 0.44 mm. These averages are calculated for a batch of substrates processed in the processing chamber, where the number of the substrates in the batch is at leastAttorney Docket No. LAM1P025WO-11824-1WO about twelve.

[0100] The following conditions were used for forming the silicon-doped carbon precoats tested in relation to FIGS. 9A-9C. The carbon-containing reactant was C2H2, which flowed to the processing chamber at a rate of about 100 sccm. The dopant was silicon, and the dopant- containing reactant was SiH4, which flowed to the processing chamber at a rate of about 150 sccm. Plasma was generated at a frequency of about 13.56MHz and 400kHz, at a power of about 400W / 1000W, respectively, and was exposed to the processing chamber for a duration of about 30s. The resulting deposition rate was about 1000 Å / min. CONCLUSION

[0101] Although the foregoing examples have been described in some detail for purposes of clarity of understanding, it will be apparent that certain changes and modifications may be practiced within the scope of the appended claims. It should be noted that there are many alternative ways of implementing the processes, systems, and apparatus of the present examples. Accordingly, the present examples are to be considered as illustrative and not restrictive, and the examples are not to be limited to the details given herein.

Claims

Attorney Docket No. LAM1P025WO-11824-1WO CLAIMS What is claimed is:

1. A method of preparing a semiconductor processing apparatus for processing substrates, the method comprising: depositing a precoat on exposed surfaces within a processing chamber of the semiconductor processing apparatus, wherein the precoat comprises a doped carbon film, and wherein the precoat is deposited on the exposed surfaces within the processing chamber in the absence of a substrate in the processing chamber.

2. The method of claim 1, wherein the semiconductor processing apparatus is configured to deposit a carbon-based material on the substrates.

3. The method of claim 2, wherein the carbon-based material is an ashable hardmask material.

4. The method of claim 2, wherein the precoat comprises carbon and a dopant, and wherein the dopant is selected from at least one of lithium, sodium, beryllium, magnesium, boron, aluminum, gallium, indium, silicon, germanium, tin, nitrogen, phosphorus, arsenic, antimony, bismuth, sulfur, selenium, tellurium, fluorine, chlorine, bromine, iodine, chromium, zinc, and gold.

5. The method of claim 4, wherein the dopant is silicon.

6. The method of claim 5, wherein the exposed surfaces within the processing chamber comprise an index plate, and the precoat is deposited on the index plate.

7. The method of claim 6, wherein the doped carbon film of the precoat reduces a degree to which a substrate slips on the index plate while the substrate is being transferred between a first station and a second station positioned within the processing chamber.

8. The method of claim 6, further comprising depositing an undercoat on bare metal surfaces exposed within the processing chamber prior to depositing the precoat, wherein the precoat is deposited on the undercoat, and wherein both the undercoat and the precoat areAttorney Docket No. LAM1P025WO-11824-1WO deposited on the index plate.

9. The method of claim 1, further comprising processing one or more substrates in the processing chamber while the precoat is present, wherein processing the one or more substrates comprises transferring at least one substrate from a first station to a second station, the first station and second station each being positioned within the processing chamber.

10. The method of claim 1, wherein the precoat comprises silicon-doped carbon having a composition comprising from about 0.01 wt% silicon to about 40 wt% silicon, and from about 20 wt% carbon to about 70 wt% carbon.

11. The method of claim 10, wherein the precoat does not comprise nitrogen.

12. The method of claim 1, wherein the precoat has a hardness ranging from about 1 GPa to about 15 GPa.

13. The method of claim 1, wherein the precoat is deposited via plasma enhanced chemical vapor deposition.

14. The method of claim 13, wherein the precoat comprises silicon-doped carbon, and wherein depositing the precoat comprises flowing a carbon-containing reactant to the processing chamber, flowing a silicon-containing reactant to the processing chamber, and generating plasma to drive a reaction between the carbon-containing reactant and the silicon-containing reactant to produce the silicon-doped carbon.

15. The method of claim 14, wherein the carbon-containing reactant comprises a hydrocarbon and the silicon-containing reactant comprises a silane.

16. The method of claim 15, wherein the carbon-containing reactant comprises C2H2and the silicon-containing reactant comprises SiH4.

17. An apparatus for processing substrates, the apparatus comprising: a processing chamber; two or more stations in the processing chamber, each station configured to process one of the substrates; an index plate positioned in the processing chamber and configured to transfer substrates fromAttorney Docket No. LAM1P025WO-11824-1WO one station to another within the processing chamber; and a controller configured to cause depositing a precoat on exposed surfaces within the processing chamber, including on the index plate, wherein the precoat comprises a doped carbon film, and wherein the precoat is deposited on the exposed surfaces within the processing chamber in the absence of a substrate in the processing chamber.

18. The apparatus of claim 17, wherein the apparatus is configured to deposit a carbon-based material on the substrates.

19. The apparatus of claim 18, wherein the carbon-based material is an ashable hardmask material.

20. The apparatus of claim 18, wherein the precoat comprises carbon and a dopant, and wherein the dopant is selected from at least one of lithium, sodium, beryllium, magnesium, boron, aluminum, gallium, indium, silicon, germanium, tin, nitrogen, phosphorus, arsenic, antimony, bismuth, sulfur, selenium, tellurium, fluorine, chlorine, bromine, iodine, chromium, zinc, and gold.

21. The apparatus of claim 20, wherein the dopant is silicon.

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