Method for forming topologically controlled amorphous carbon polymer films

Abstract

A method for forming a topology-controlled layer on a patterned recess of a substrate, comprising: (i) depositing a Si-free C-containing film having filling capability on the patterned recess of the substrate by pulsed plasma assisted deposition to fill the recess in a bottom-up manner or in a bottomless manner; and (ii) plasma ashing the bottom-up or bottomless film filled in the recess to remove a top portion of the filling film in a manner that mainly or substantially only a bottom portion of the filling film is left or mainly or substantially only a sidewall portion of the filling film is left.

Description

Technical Field

[0001] The present invention generally relates to a method of forming a topology-controlled amorphous carbon film on patterned recessed portions of a substrate. Background Art

[0002] In the process of manufacturing integrated circuits, such as those used for shallow trench isolation, intermetallic dielectric layers, passivation layers, etc., it is often necessary to fill trenches (generally any recessed portion having an aspect ratio of one or higher) with insulating materials. However, as the wiring pitch of large-scale integration (LSI) devices is miniaturized, void-free filling of high aspect ratio spaces (e.g., AR ≥ 3) has become increasingly difficult due to limitations of existing deposition processes.

[0003] In view of the above, the inventors have developed a gap filling technology for depositing flowable films and disclosed the technology in U.S. patent application No. 16 / 026,711 filed on July 3, 2018, which provides complete gap filling without substantially forming voids by using plasma-assisted deposition of hydrocarbon precursors without the need for nitrogen, oxygen or hydrogen plasma, and the disclosure of the patent application is incorporated herein by reference in its entirety.

[0004] However, if some applications in which a sacrificial etch stop layer or a protective layer is necessary only at the bottom of a recess, for example, require depositing amorphous carbon only at the bottom of a trench in a substrate using the above-mentioned gap filling technique, the following problems may exist: i) a certain amount of film may be deposited on the top surface of the substrate (although the amount is small but not negligible); ii) the amount of film deposited at the bottom of each trench may be irregular depending on the structural volume of each trench (see Figure 8 (a)); and iii) even if the structural volume of each trench is similar, there may be some randomness in the gap filling (see Figure 8 The present inventors hereby provide a solution to the above-mentioned problem.

[0005] In other applications such as 3D NAND flash memory, ultra-deep hole straight etching is required. However, due to the sidewall etching during the hole etching, it is difficult to maintain a straight structure, resulting in reduced CD integrity. The inventors have found that the above gap filling technology can provide a solution to the above problem.

[0006] Any discussion of problems and solutions involved in the related art has been included in this disclosure solely for the purpose of providing a context for the present invention, and should not be construed as an admission that any or all of the issues discussed were known at the time the present invention was made. Summary of the invention

[0007] In view of the above, some embodiments provide a method for forming a topologically controlled layer on a patterned recess of a substrate, comprising: (i) depositing a Si-free C-containing film having filling capability on the patterned recess of the substrate by pulsed plasma assisted deposition to fill the recess in a bottom-up manner or a bottomless manner; and (ii) plasma ashing the bottom-up or bottomless film filled in the recess to remove the top portion of the filling film in a manner that mainly leaves only the bottom portion of the filling film or mainly leaves only the sidewall portion of the filling film. According to the above embodiments, by using a gap filling technique, the topology of the film can be manipulated. The degree of fluidity of the film relative to the groove size can mainly determine whether the deposition is a bottom-up deposition or a bottomless deposition.

[0008] When the fluidity of the film is sufficiently high relative to the target trench, bottom-up deposition occurs, and after the trench is completely filled and the film is further deposited above the trench, by plasma ashing the film, the top portion of the film above the trench and the upper portion of the film filled in the trench can be equally removed to a uniform depth of the trench to obtain a trench filled with a film having a substantially uniform depth.

[0009] When the flowability of the film is sufficiently low relative to the target trench, bottomless deposition occurs; however, since the film is flowable, even when the film does not reach the bottom of the trench and close the upper opening of the trench, the film can be deposited along the sidewalls of the trench to cover the sidewalls to a certain depth from the top surface of the substrate. After the deposition of the film is completed, the portion of the film that closes the opening of the trench can be removed by plasma ashing the film to open the trench, leaving the sidewall film as a spacer. Thereafter, ultra-deep hole straight etching can be performed. Since the bottom of the trench is substantially not covered by the film, and the sidewall film can protect the sidewall from being etched during the ultra-deep hole straight etching, etching can be performed in the depth direction to form an ultra-deep straight hole without reducing CD integrity.

[0010] For the purpose of summarizing various aspects of the present invention and the advantages achieved over the related art, certain objects and advantages of the present invention are described in this disclosure. Of course, it should be understood that not all of these objects or advantages may be achieved according to any particular embodiment of the present invention. Thus, for example, those skilled in the art will recognize that the present invention may be implemented or performed in a manner that achieves or optimizes one advantage or a group of advantages as taught herein, without having to achieve other objects or advantages as may be taught or indicated herein.

[0011] Further aspects, features and advantages of the present invention will become apparent from the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] These and other features of the present invention will now be described with reference to the drawings of preferred embodiments, which are intended to illustrate and not to limit the present invention. The drawings are greatly simplified for illustrative purposes and are not necessarily to scale.

[0013] Figure 1A is a schematic diagram of a PEALD (plasma enhanced atomic layer deposition) apparatus for depositing dielectric films that may be used in one embodiment of the present invention.

[0014] Figure 1B A schematic diagram of a precursor supply system using a flow-through system (FPS) that may be used in one embodiment of the present invention is illustrated.

[0015] Figure 2 Figures are schematic cross-sectional views of trenches illustrating bottom-up deposition ((a)(b)(c)) and bottomless deposition ((a)(d)(e)) according to embodiments of the present invention.

[0016] Figure 3 STEM photographs of cross-sectional views of trenches according to embodiments of the present invention are shown, wherein: (a) a trench subjected to bottom-up deposition, (b) a trench subjected to subsequent O2 / Ar ashing, (c) or a trench subjected to N2 / H2 ashing.

[0017] Figure 4 Schematic diagram of a STEM photograph showing a cross-sectional view of a trench subjected to bottomless deposition (300 cycles) without ashing.

[0018] Figure 5 Schematic diagram of a STEM image showing a cross-sectional view of a trench subjected to bottomless deposition (300 cycles) followed by ashing (90 seconds) according to one embodiment of the present invention.

[0019] Figure 6 Schematic diagram of a STEM photograph showing a cross-sectional view of a trench subjected to bottomless deposition (350 cycles) without ashing.

[0020] Figure 7 Schematic diagram of a STEM image showing a cross-sectional view of a trench subjected to bottomless deposition (350 cycles) followed by ashing (90 seconds) according to one embodiment of the present invention.

[0021] Figure 8 STEM images of cross-sectional views of trenches subjected to bottom-up deposition are shown, wherein (a) shows trenches having different widths and (b) shows trenches filled with irregular amounts of film.

[0022] Fig. 9STEM photographs of cross-sectional views of trenches deposited from the bottom up according to one embodiment of the present invention are shown, wherein (a) shows the trench after deposition is completed, and (b) shows the trench after ashing.

[0023] Fig.10 STEM photographs of cross-sectional views of trenches deposited from the bottom up (fully filled) according to an embodiment of the present invention are shown, wherein the original (a) represents a mixture of wide trenches and narrow trenches with different widths (the scale bar represents 300 nm), the original (b) represents trenches of medium width (the scale bar represents 60 nm), the original (c) represents wide trenches with slightly different widths (the scale bar represents 60 nm), column (1) represents trenches of fully filled deposition (210 deposition cycles) before ashing, column (2) represents trenches after ashing for 105 seconds, column (3) represents trenches after ashing for 129 seconds, and column (4) represents trenches after ashing for 165 seconds.

[0024] Fig.11 STEM photographs of cross-sectional views of grooves deposited from the bottom up according to one embodiment of the present invention are shown, wherein (a) represents the groove when the deposition is fully filled (210 deposition cycles), (b) represents the groove after ashing for 240 seconds, and (c) represents the groove after ashing for 300 seconds.

[0025] Fig.12 A diagram illustrating a film forming process sequence according to an embodiment of the present invention, wherein gray cells represent an on state, white cells represent an off state, and the width of each column does not represent the duration of each process. DETAILED DESCRIPTION

[0026] In the present disclosure, depending on the context, "gas" may include gasified solids and / or liquids and may consist of a single gas or a mixture of gases. Similarly, depending on the context, the article "a" refers to a species or a genus including multiple species. In the present disclosure, the process gas introduced into the reaction chamber through the shower head may contain a silicon-free precursor and an additive gas, substantially consist of a silicon-free precursor and an additive gas, or consist of a silicon-free precursor and an additive gas. The additive gas may include a plasma-generating gas for exciting the precursor to form an amorphous carbon polymer when RF power is applied to the additive gas. The additive gas may be an inert gas, which may be fed into the reaction chamber as a carrier gas and / or a diluent gas. The additive gas may not contain a reactive gas for oxidizing or nitriding the precursor. Alternatively, the additive gas may contain a reactive gas for oxidizing or nitriding the precursor to the extent that it does not interfere with plasma polymerization to form an amorphous carbon-based polymer. In addition, in some embodiments, the additive gas contains only a plasma-generating gas (e.g., a rare gas). The precursor and additive gas may be introduced into the reaction space as a mixed gas or separately into the reaction space. Precursors may be introduced using carrier gases such as rare gases. Gases other than process gases, i.e. gases introduced without passing through a showerhead, may be used, for example, to seal the reaction space, including sealing gases such as rare gases. In some embodiments, the term "precursor" generally refers to a compound that participates in a chemical reaction that produces another compound, and in particular refers to a compound that constitutes a membrane matrix or a main skeleton of a membrane, and the term "reactant" refers to a compound other than a precursor that activates a precursor, modifies a precursor, or catalyzes a reaction of a precursor, wherein the reactant may provide an element (e.g., O, C, N) to the membrane matrix and, when in an excited state, becomes part of the membrane matrix. The term "plasma generating gas" refers to a compound other than a precursor and a reactant that generates a plasma when exposed to electromagnetic energy, wherein the plasma generating gas may not provide an element (e.g., O, C, N) to the membrane matrix, and the element becomes part of the membrane matrix. The term "plasma ashing gas" refers to a gas that ashes the film when in a state of direct excitation (direct plasma) or remote excitation (remote plasma). In some embodiments, the "plasma ashing gas" is a single gas or a mixed gas of two or more gases. The term "ashing" refers to the removal of organic matter using a plasma, leaving behind a mineral component as a residue (ash), which is typically removed with a vacuum pump.

[0027] In some embodiments, "film" refers to a layer that covers the entire target or relevant surface and is substantially free of pores and extends continuously in a direction perpendicular to the thickness direction, or simply refers to a layer that covers the target or relevant surface. In some embodiments, "layer" refers to a structure with a certain thickness formed on the surface, or a synonym for a film or non-film structure. The film or layer may be composed of a discrete single film or layer with certain characteristics, or it may be composed of multiple films or layers, and the boundaries between adjacent films or layers may be clear or unclear and may be created based on the physics, chemistry and / or any other characteristics, formation process or sequence and / or function or purpose of the adjacent films or layers. In addition, in the present disclosure, since the workable range can be determined based on conventional work, any two numbers of the variable can constitute the workable range of the variable, and any range indicated can include or exclude endpoints. In addition, any indicated variable values ​​(whether or not they are indicated with "about") can refer to exact values ​​or approximate values ​​and include equivalent values, and in some embodiments can refer to average values, medians, representative values, majority values, etc. Furthermore, in the present disclosure, in some embodiments, the terms “consisting of” and “having” independently mean “typically or broadly including,” “comprising,” “consisting essentially of,” or “consisting of. In the present disclosure, in some embodiments, any defined meaning does not necessarily exclude the ordinary and customary meaning.

[0028] In the present disclosure, in some embodiments, "continuously" refers to no breaking of vacuum, no interruption over a time axis, no intervening step of any material, no immediate change in processing conditions as the next step, or no discrete physical or chemical structures between two structures other than the two structures.

[0029] In the present disclosure, the term "filling ability" (also referred to as "flowability") refers to the ability to fill a gap substantially without voids (e.g., without voids having a size of approximately 5 nm or greater in diameter) or seams (e.g., without seams having a length of approximately 5 nm or greater), wherein when a film is deposited in a wide trench having an aspect ratio of approximately 1 or greater, a seamless / void-free bottom-up growth of the layer is observed.

[0030] The flowability often manifests as a concave film surface at the bottom of a wide trench before filling the trench, and also manifests as a substantially planar film top surface (planarization) when continuously deposited after completely filling the trench. Such deposition is referred to as "bottom-up deposition".

[0031] When the trench is narrow and deep, the film may not reach the bottom of the trench even if it is flowable. In this case, the flowability often manifests itself as a roughly or substantially conformal film along the sidewalls of the trench, with essentially no film at the bottom of the trench and the top opening of the trench usually closed by the film. Since the film is flowable, the sidewall film flows and extends down the sidewall, thereby forming a thin film, in which the average thickness of the substantially conformal portion of the film (except for the top portion that closes the top opening of the trench, which is subsequently removed by ashing) to the depth of the film in the trench (the length extending along the sidewall toward the bottom) can be in the range of 0.1% to 10% (typically 0.5% to 5%). Such deposition is called "bottomless deposition".

[0032] In the present disclosure, the recess between adjacent protrusion structures and any other recess pattern are referred to as "grooves". That is, a groove is any recess pattern comprising a hole / through hole. For bottom-up deposition, in some embodiments, the groove has a width of about 20nm to about 100nm (typically about 30nm to about 50nm) (wherein when the groove has a length substantially the same as the width, it can be referred to as a hole / through hole), a depth of about 30nm to about 100nm (typically about 40nm to about 60nm), and an aspect ratio of about 2 to about 10 (typically about 2 to about 5). For bottomless deposition, in some embodiments, the groove has a width (CD) of about 5.5nm to about 200nm (typically about 10nm to about 100nm), a depth of about 800nm ​​to about 10,000nm (typically about 300nm to about 8,000nm), and an aspect ratio of about 15 to about 150 (typically about 20 to about 100). The appropriate dimensions of the trenches may vary with process conditions, film fluidity, film composition, intended application, etc. By, for example, adjusting the film fluidity, bottom-up deposition and bottomless deposition may be achieved in trenches having dimensions other than those described above.

[0033] In the present disclosure, the terms "substantially no deposition", "substantially no film", etc. refer to an amount functionally equivalent to zero, an insignificant or negligible amount, an amount that does not substantially interfere with subsequent processes (e.g., ashing), an amount below a detectable or observable amount, etc.

[0034] In the present disclosure, in some embodiments, any defined meaning does not necessarily exclude the ordinary and customary meaning. Moreover, in the present disclosure, "the present invention" refers to at least one of the embodiments or aspects disclosed herein explicitly, necessarily or inherently.

[0035] The embodiments will be explained with reference to preferred embodiments. However, the present invention is not intended to be limited to these preferred embodiments.

[0036] Some embodiments provide a method for forming a topologically controlled layer on a patterned recess of a substrate, comprising: (i) depositing a Si-free C-containing film having filling capability on the patterned recess of the substrate by pulsed plasma assisted deposition to fill the recess in a bottom-up manner or a bottomless manner; and (ii) plasma ashing the bottom-up or bottomless film filled in the recess to remove the top portion of the filling film in a manner that mainly leaves only the bottom portion of the filling film or mainly leaves only the sidewall portion of the filling film. The Si-free C-containing film can generally be an amorphous carbon polymer film that is a flowable film. When the amorphous carbon polymer film is formed by using a plasma assisted method, the resulting amorphous carbon polymer film is composed of a hydrogenated amorphous carbon polymer. In the present disclosure, the hydrogenated amorphous carbon polymer may be referred to as an amorphous carbon polymer, which may also be referred to as "aC:H" or simply as the abbreviation "aC". Furthermore, in the present disclosure, unless otherwise specified, SiC, SiCO, SiCN, SiCON, and the like are abbreviations indicating a film type in a non-stoichiometric manner (indicated simply by a main constituent element).

[0037] In some embodiments, in step (i), a Si-free C-containing film is deposited using a hydrocarbon precursor. In some embodiments, step (i) includes: (ia) supplying a precursor to a reaction space where a substrate is placed, and (ib) exposing a patterned recess of the substrate to plasma to deposit a Si-free C-containing film in the patterned recess, wherein step (ib) is intermittently performed in a pulsed plasma manner, and step (ia) is performed continuously or intermittently as a prerequisite step of step (ib) without overlapping with step (ib). In some embodiments, the Si-free C-containing film is substantially composed of hydrocarbons.

[0038] Deposition of flowable films is known in the art; however, conventional deposition of flowable films uses chemical vapor deposition (CVD) with continuous application of RF power, because pulsed plasma assisted deposition such as PEALD is well known for depositing conformal films, which are films having characteristics that are completely opposite to those of flowable films. In some embodiments, the flowable film is a silicon-free carbon-containing film composed of an amorphous carbon polymer, and although any suitable one or more hydrocarbon precursors may be candidates, in some embodiments, the precursor includes an unsaturated or cyclic hydrocarbon having a vapor pressure of 1,000 Pa or more at 25°C. In some embodiments, the precursor is at least one selected from the following: C2-C8 alkyne (C n H 2n-2 ), C2-C8 olefins (C n H 2n )、C2-C8 diene (C n H n+2 )、C3-C8 cycloolefins, C3-C8 annulene (C n H n), C3-C8 cycloalkanes and the aforementioned substituted hydrocarbons. In some embodiments, the precursor is ethylene, acetylene, propylene, butadiene, pentene, cyclopentene, benzene, styrene, toluene, cyclohexene and / or cyclohexane.

[0039] In some embodiments, as a gap filling technique for depositing a flowable film, a method disclosed in U.S. patent application Ser. No. 16 / 026,711 can be used, which provides complete gap filling without substantially forming voids by using plasma-assisted deposition of a hydrocarbon precursor under conditions where nitrogen, oxygen or hydrogen plasma is not required, and the disclosure of the U.S. patent application is incorporated herein by reference in its entirety.

[0040] By changing the deposition conditions or process parameters, a non-flowable film can be formed. For example, such parameters include, but are not limited to, the partial pressure of the precursor, the deposition temperature, the deposition pressure, etc. For example, by increasing the deposition temperature, reducing the deposition pressure and / or reducing the precursor ratio (the ratio of the precursor flow rate to the carrier gas / dilution gas flow rate), the fluidity of the film becomes lower. In some embodiments, process (i) (deposition process) is performed by plasma enhanced atomic layer deposition (PEALD) or other cyclic plasma assisted deposition (e.g., cyclic PECVD). As plasma, capacitively coupled plasma, inductively coupled plasma, remote plasma, plasma generated by RF power, plasma generated by microwaves, etc. can be used.

[0041] In some embodiments, the plasma ashing in step (ii) is performed using a direct or remote oxygen or hydrogen plasma. In some embodiments, the direct or remote oxygen or hydrogen plasma is a direct or remote plasma of a gas selected from the following: completely H2; a mixture of Ar and H2 (Ar / H2 flow ratio of 0.005 to 0.995, typically 0.05 to 0.75); a mixture of He and H2 (He / H2 flow ratio of 0.005 to 0.995, typically 0.05 to 0.75); a mixture of N2 and H2 (N2 / H2 flow ratio of 0.005 to 0.995, typically 0.05 to 0.75); completely O2; a mixture of O2 and Ar (O2 / Ar flow ratio is 0.005 to 0.995, typically 0.05 to 0.75); a mixture of O2 and He (O2 / He flow ratio is 0.005 to 0.995, typically 0.05 to 0.75); a mixture of O2 and N2 (O2 / N2 flow ratio is 0.005 to 0.995, typically 0.05 to 0.75).

[0042] In some embodiments, the aspect ratio of the recess is in the range of 10 to 150 (typically 15 to 100), the depth of the recess is greater than 200 nm, wherein the recess is filled with a film in a bottomless manner in step (i) and the top portion of the filled film closes the top opening of the recess. In some embodiments, plasma ashing is performed in step (ii) to open the closed top portion of the recess and leave mainly or substantially only the sidewall portion of the filled film.

[0043] In some embodiments, the substrate has a plurality of recesses having an aspect ratio of 2 to 30 (typically 3 to 20), wherein the recesses are filled with a film in a bottom-up manner in step (i), wherein there are variations in surface topology due to a loading effect. In some embodiments, step (i) is continued until planarization of the film occurs over the plurality of recesses, and then plasma ashing is performed in step (ii) to make the surface topology of the film filled in the plurality of recesses uniform, leaving mainly or substantially only the bottom portion of the filled film.

[0044] The embodiments will be described with reference to the accompanying drawings. However, the present invention is not intended to be limited to these drawings.

[0045] Figure 2 Schematic cross-sectional views of trenches for bottom-up deposition ((a)(b)(c)) and bottomless deposition ((a)(d)(e)) according to embodiments of the present invention. Figure 2 In (a), a substrate having grooves is provided, wherein for bottom-up deposition, substrate 21 has grooves 20 having a width wide enough to allow a flowable film to flow into the grooves and having a depth small enough to allow the flowable film to reach the bottom of grooves 20, and for bottomless deposition, substrate 31 has grooves 30 having a width wide enough to allow a flowable film to flow into the grooves but narrow enough to block the top opening of grooves 30 by the film before the film reaches the bottom of grooves 30, and having a depth large enough not to allow the flowable film to reach the bottom of grooves 30. For example, suitable groove dimensions are described in the present disclosure and can be selected according to, for example, the fluidity of the film. It should be noted that, Figure 2 Oversimplified and not to scale.

[0046] Next, during the deposition process, the same deposition conditions can be used for both the bottom-up deposition in (b) and the bottomless deposition in (d), except for the number of deposition cycles, the duration of ashing, etc., which are changed according to the size of the trench, the target deposition thickness of the film, the target ashing amount, the target final topology of the film, etc. In (b), the flowable film fills the trench 20 in a bottom-up manner and is continuously deposited on the substrate 21 after the trench 20 is completely filled until the top surface of the film 22 is flattened. Flattening can be achieved due to the fluidity of the film. In (d), the flowable film is deposited on the top of the substrate 31 and flows into the trench 30, thereby moving downward along the sidewall of the trench 30 in a bottomless manner, while the top opening of the trench 30 is blocked by the flowable film 32. Since the flowable film flows downward along the sidewall of the trench 30 with an aspect ratio of, for example, about 10 to 100, the film on the sidewall is substantially conformal along the sidewall, which can be used as a spacer. It should be noted that bottom-up deposition and bottomless deposition can be performed on trenches of the same size by adjusting the flowability of the film for each deposition. For example, the method of adjusting flowability disclosed in US Patent Application No. 16 / 026,711 can be used.

[0047] Next, in an ashing process, amorphous carbon constituting the film is removed (ashed) from the top surface exposed to plasma to a depth suitable for only bottom topology or only sidewall topology. In (c), by removing a portion of the film 22 deposited on the top surface of the substrate 21 and an upper portion of the film 22 filled in the trench 20 in a bottom-up manner, a film 23 having only bottom topology can be obtained, which is uniform and has a substantially uniform depth. In (e), by removing a portion of the film 32 deposited on the top surface of the substrate 31 and an upper portion of the film 32 that closes the upper opening of the trench 30 in a bottomless manner, a film 33 having only sidewall topology can be obtained, which is uniform and has a substantially uniform thickness.

[0048] In some embodiments, it is preferred that the deposition process uses an ALD-like procedure (e.g., feed / purge / plasma strike / purge), where the purge after the feed is voluntarily severely shortened to maintain a high partial pressure of the precursor during the plasma strike, as disclosed in U.S. Patent Application No. 16 / 026,711. This is clearly distinguished from the ALD chemistry or mechanism. The above process can be based on pulsed plasma CVD, which also gives the resulting film good filling ability, but as discussed later, an ALD-like procedure can be more beneficial.

[0049] In some embodiments, unlike conventional ALD, key aspects of the fluidity of the deposited film include:

[0050] 1) A sufficiently high partial voltage during the entire RF on period for polymerization / chain growth to progress;

[0051] 2) sufficient energy to activate the reaction (defined by RF on period and RF power), without too long an RF on period; and

[0052] 3) Polymerization / chain growth temperature and pressure set above the melting point of the flowable phase but below the boiling point of the deposited material.

[0053] In some embodiments, the process parameter ranges are adjusted as follows to adjust the fluidity of the film:

[0054] Table 1 (values ​​are approximate)

[0055] Low ← Viscosity → High Precursor partial pressure (Pa) >50 (preferably >200) Chip temperature (℃) -10 to 200 (preferably 50 to 150) Total pressure(Pa) 300 to 101325 (preferably >500)

[0056] In terms of pressure, high pressure is preferred for fluidity because gravity and surface tension are the driving forces for the film to flow at the bottom. In terms of temperature, low temperature is preferred for fluidity (which is much less intuitive), although high temperature favors polymer chain growth rate.

[0057] Fig.12 A diagram illustrating a film forming process sequence according to an embodiment of the present invention, wherein the gray cells represent the on state, and the white cells represent the off state, and the width of each column does not represent the duration of each process. Both bottom-up deposition and bottomless deposition can use this simplified process sequence, and in some embodiments, the same deposition conditions can be used for both bottom-up deposition and bottomless deposition, except for the number of deposition cycles, the duration of ashing, etc., which are changed according to the size of the groove, the target deposition thickness of the film, the target ashing amount, the target final topology of the film, etc.

[0058] This process sequence includes a deposition process ("feed"→"purge"→"RF pulse-1" (plasma polymerization)→"purge"), and a plasma ashing process ("stabilization"→"RF pulse-2" (plasma ashing)→"purge"). The plasma polymerization process includes depositing an amorphous carbon polymer film on a substrate having grooves by PEALD-like deposition using a Si-free and metal-containing precursor and a plasma generating gas, wherein the plasma generating gas generates plasma by applying RF power (RF) between two electrodes, and the substrate is placed between the two electrodes in parallel, wherein RF power is applied in each sub-layer deposition cycle of the PEALD-like deposition, wherein the plasma generating gas and the carrier gas flow continuously and also act as a purge gas during the "purge" period after the "feed" and during the "purge" period after the "RF pulse-1".

[0059] In some embodiments, the feed time is in the range of 0.3 to 10 seconds (typically 0.6 to 2 seconds), the purge time after the feed is in the range of 0 to 0.5 seconds (typically 0 to 0.3 seconds), the RF time is in the range of 0.5 to 2 seconds (typically 0.8 to 1.5 seconds), the purge time after the RF is in the range of 0 to 0.5 seconds (typically 0 to 0.1 seconds), the carrier gas flow rate is in the range of 0 to 0.8 slm (typically 0.1 to 0.3 slm), the plasma generation gas flow rate is in the range of 0 to 0.5 slm (typically 0.1 to 0.3 slm), and the RF power is in the range of 50 to 400 W (typically 75 to 200 W) for a 300-mm wafer (for wafers of different sizes, the above wattages are calculated per unit area (cm2) of each wafer). 2 ) of W application).

[0060] When, for example, a volatile hydrocarbon precursor is polymerized by plasma and deposited on the surface of a substrate, the fluidity of the film will be temporarily obtained, wherein the gaseous monomer (precursor) is activated or fragmented by the energy provided by the plasma gas discharge to initiate polymerization, and when the resulting polymer material is deposited on the surface of the substrate, the material shows temporary flowable behavior. When the deposition step is completed, the flowable film is no longer flowable, but solidified, and therefore does not require a separate solidification process.

[0061] The deposition process is a PEALD-like process, in which a cycle of forming a sublayer (usually thicker than a monolayer) before starting the plasma ashing process can be repeated q times until an amorphous carbon polymer film of desired thickness is obtained. For bottom-up deposition, depending on the size of the trench, the intended use of the film, etc., q is an integer from 5 to 100 (preferably 25 to 50) to deposit an amorphous carbon polymer film with a thickness of 2.5 nm to 50 nm (preferably 7.5 nm to 25 nm) above the top surface of the substrate before starting the plasma ashing process; for bottomless deposition, depending on the size of the trench, the intended use of the film, etc., q is an integer from 10 to 200 (preferably 40 to 100) to deposit an amorphous carbon polymer film with a thickness of 5 nm to 100 nm (preferably 20 nm to 50 nm) above the top surface of the substrate before starting the plasma ashing process.

[0062] Next, a plasma ashing process is started, which includes feeding an ashing gas (H2 or O2, or a mixture of the foregoing with N2, Ar and / or He) into the reaction space ("stabilization"), the ashing gas is excited by RF power (RF) to generate plasma and ashes the amorphous carbon polymer film ("RF pulse-2"), followed by purge ("purge"), wherein the ashing gas is continuously fed into the reaction chamber throughout the plasma ashing process. In some embodiments, the RF power for plasma ashing is in the range of 50 to 500 W (typically 50 to 200 W), the pressure is 100 Pa to 1000 Pa (typically 200 to 600 Pa), the duration is 5 to 200 seconds (typically 10 to 100 seconds), the stabilization time is in the range of 5 to 60 seconds (typically 10 to 30 seconds), the purge time after RF is in the range of 5 to 60 seconds (typically 10 to 30 seconds), and the ashing gas flow rate is in the range of 0.1 to 10 slm (typically 0.5 to 2 slm).

[0063] In some embodiments, during the entire process, the carrier gas is continuously fed into the reaction space, for example, in the range of 0 sccm to 2000 sccm (preferably 100 sccm to 500 sccm). In addition, the process temperature can be in the range of -50°C to 175°C (preferably 35°C to 150°C).

[0064] The plasma generation gas in the deposition process and the ashing gas in the plasma ashing process may be the same or different, for example, both may be Ar and / or He.

[0065] The continuous flow of the carrier gas can be achieved using a flow-through system (FPS), wherein the carrier gas line is provided with a bypass line having a precursor tank (bottle), and switching is performed between the main line and the bypass line, wherein when only the carrier gas is intended to be fed to the reaction chamber, the bypass line is closed, and when both the carrier gas and the precursor gas are intended to be fed to the reaction chamber, the main line is closed, and the carrier gas flows through the bypass line and flows out of the bottle together with the precursor gas. In this way, the carrier gas can flow continuously into the reaction chamber and the precursor gas can be carried in a pulsed form by switching between the main line and the bypass line. Figure 1B FIG. 2 illustrates a precursor supply system using a flow-through system (FPS) according to one embodiment of the present invention (a black valve indicates that the valve is closed). Figure 1BAs shown in (a), when a precursor is fed into a reaction chamber (not shown), a first carrier gas such as Ar (or He) flows through a gas line having valves b and c, and then enters a bottle (reservoir) 26. The carrier gas flows out of the bottle 26 while carrying an amount of the precursor gas corresponding to the vapor pressure inside the bottle 26, flows through a gas line having valves f and e, and then is fed into the reaction chamber together with the precursor. In the above, valves a and d are closed. When only a carrier gas (rare gas) is fed into the reaction chamber, as shown in FIG. Figure 1B As shown in (b), the carrier gas flows through the gas line having valve a while bypassing the bottle 26. In the above, valves b, c, d, e and f are closed.

[0066] The process cycle can be carried out using any suitable means, including for example Figure 1A The device shown in FIG. Figure 1A Schematic diagram of a PEALD apparatus, which is preferably combined with a controller programmed to perform the sequence described below, and can be used in some embodiments of the present invention. In this figure, a pair of conductive plate electrodes 4, 2 are provided in parallel and face each other in the interior 11 (reaction zone) of the reaction chamber 3, HRF power (13.56 MHz or 27 MHz) 25 is applied to one side, and the other side 12 is electrically grounded, and plasma is ignited between the electrodes. A temperature regulator is provided in the lower platform 2 (lower electrode), and the temperature of the substrate 1 placed thereon is kept constant at a given temperature. The upper electrode 4 also serves as a shower plate, and reactant gas and / or dilution gas (if any) and precursor gas are introduced into the reaction chamber 3 through gas pipelines 27 and gas pipelines 28 and through the shower plate 4, respectively. In addition, in the reaction chamber 3, an annular pipe 13 with an exhaust line 7 is provided, and the gas in the interior 11 of the reaction chamber 3 is exhausted through the exhaust line. In addition, the transfer chamber 5 disposed below the reaction chamber 3 is provided with a sealing gas line 24 to introduce sealing gas into the interior 11 of the reaction chamber 3 via the interior 16 (transfer zone) of the transfer chamber 5, and a separation plate 14 for separating the reaction zone and the transfer zone is provided in the transfer chamber 5 (a gate valve through which a wafer is transferred to or from the transfer chamber is omitted in the figure). The transfer chamber is also provided with an exhaust line 6. In some embodiments, deposition of a multi-element film and surface treatment are performed in the same reaction space, so that all steps can be performed continuously without exposing the substrate to air or other oxygen-containing atmospheres.

[0067] In some embodiments, Figure 1A In the device depicted in Figure 1B The system for switching the flow of the inert gas and the flow of the precursor gas illustrated in FIG. 1 (described above) can be used to introduce the precursor gas in pulses without substantially fluctuating the pressure of the reaction chamber.

[0068] The skilled artisan will recognize that the apparatus includes one or more controllers (not shown) programmed or otherwise configured to enable the deposition and reactor cleaning processes described elsewhere herein to be performed. As the skilled artisan will appreciate, the one or more controllers may be in communication with various power supplies, heating systems, pumps, robotic devices, and gas flow controllers or valves of the reactor.

[0069] In some embodiments, a dual chamber reactor (for processing two portions or compartments of a wafer positioned close to each other) may be used, wherein the reactant gas and noble gas may be supplied through shared lines while the precursor gas is supplied through unshared lines.

[0070] The film with filling capability can be applied to various semiconductor devices, including but not limited to cell isolation in 3D cross-point memory devices, self-aligned vias, pseudo gates (replacing current poly-Si), reverse tone patterning, PC RAM isolation, cutting hard mask and DRAM storage node contact (SNC) isolation.

[0071] Examples

[0072] In the following examples where conditions and / or structures are not specified, such conditions and / or structures can be easily provided by those skilled in the art according to routine experiments in view of the present disclosure. It will be appreciated by the skilled artisan that the apparatus used in the examples includes one or more controllers (not shown) programmed or otherwise configured to enable the deposition and reactor cleaning processes described elsewhere herein. As will be appreciated by the skilled artisan, the one or more controllers are in communication with gas flow controllers or valves of various power supplies, heating systems, pumps, robotic devices, and reactors.

[0073] Reference Example 1( Figure 3 )

[0074] use Figure 1A The equipment shown in Figure 1B The gas supply system (FPS) shown in FIG. 1 is operated under the conditions shown in Table 2 below according to Fig.12 The process sequence shown in the embodiment deposits an amorphous carbon polymer film on a Si substrate (with a diameter of 300 mm and a thickness of 0.7 mm) having a trench with an opening of about 25 to 35 nm and a depth of about 85 nm (aspect ratio of about 2.4 to 3.4) in a bottom-up manner by a PEALD-like process. The film is deposited to completely fill the trench and further accumulates thereon to form a flat top surface. The PEALD-like cycle is repeated 242 times (p=242). Thereafter, according to Fig.12 The process sequence shown in is ashing performed continuously under the conditions shown in Table 2 below using a mixture of O 2 and Ar or a mixture of N 2 and H 2 .

[0075] Table 2 (values ​​are approximate)

[0076]

[0077] Figure 3 STEM images of cross-sectional views of trenches are shown, where: (a) a trench subjected to bottom-up deposition, (b) a trench subjected to O2 / Ar ashing, (c) a trench subjected to N2 / H2 ashing. Figure 3 As shown in the figure, it is confirmed that the amorphous carbon polymer film is able to flow effectively and completely fill all the grooves (regardless of the size differences) and further accumulate thereon to form a flat top surface, and that through the ashing process, the amorphous carbon polymer film can be completely removed or ashed without reducing the CD integrity, that is, by controlling the ashing time, the desired amount of amorphous carbon polymer film can be removed without reducing the CD integrity.

[0078] Example 1

[0079] An amorphous carbon polymer film was deposited on a Si substrate (having a diameter of 300 mm and a thickness of 0.7 mm) having a groove having an opening of about 20 nm and having a depth of about 200 nm (aspect ratio of about 10) by a PEALD-like process in a bottom-up manner under the same conditions as in Reference Example 1, except that the deposition cycle was repeated 210 times (p=210) so that the film accumulated to a thickness of 100 nm on the top surface of the substrate. Thereafter, ashing was continuously performed using a mixture of O2 and Ar in the same manner as in Reference Example 1, except that the RF time was shortened to 90 seconds in order to form a film structure having only a bottom topology, wherein the film was ashed from the top surface of the substrate to a depth of 181 nm.

[0080] Fig. 9 The STEM images of the cross-section of the trenches subjected to bottom-up deposition are shown, wherein (a) shows the trenches after deposition is completed, and (b) shows the trenches after ashing. Fig. 9 As shown in , it is confirmed that the amorphous carbon polymer film is effectively flowable and completely fills all the grooves and further accumulates thereon to form a flat top surface, and through the ashing process, the amorphous carbon polymer film in all the grooves can be uniformly removed or ashed without degrading the CD integrity, thereby forming a uniform film structure with a uniform bottom-only topology.

[0081] Example 2

[0082] An amorphous carbon polymer film was deposited on a Si substrate having grooves in the same manner as in Example 1, except that the ashing time was changed.

[0083] Fig.10STEM images of cross-sectional views of trenches subjected to bottom-up deposition (complete filling) are shown, wherein the original (a) represents a mixture of wide and narrow trenches with different widths (the scale bar represents 300 nm), the original (b) represents trenches of medium width (the scale bar represents 60 nm), the original (c) represents wide trenches with slightly different widths (the scale bar represents 60 nm), column (1) represents trenches of complete filling deposition (210 deposition cycles) before ashing, column (2) represents trenches after ashing for 105 seconds, column (3) represents trenches after ashing for 129 seconds, and column (4) represents trenches after ashing for 165 seconds.

[0084] Fig.11 STEM images of cross-sectional views of trenches subjected to bottom-up deposition are shown, wherein (a) represents the trench when full filling deposition (210 deposition cycles) is completed, (b) represents the trench after 240 seconds of ashing, and (c) represents the trench after 300 seconds of ashing.

[0085] like Fig.10 and 11 As shown in , it is confirmed that the amorphous carbon polymer film is effectively flowable and completely fills all the grooves and further accumulates thereon to form a flat top surface, and that by an ashing process, the amorphous carbon polymer film in all the grooves can be uniformly removed or ashed without reducing the CD integrity, thereby forming a uniform film structure with a uniform bottom-only topology. It is also confirmed that, unexpectedly, the combination of full-fill deposition and ashing can uniformly achieve bottom-only deposition without substantially any loading effect.

[0086] Reference Example 2

[0087] An amorphous carbon polymer film was deposited on a Si substrate (having a diameter of 300 mm and a thickness of 0.7 mm) having a groove having an opening of approximately 150 nm and having a depth of approximately 2500 nm (aspect ratio of approximately 17) in a bottomless manner by a PEALD-like process under the same conditions as in Reference Example 1, except that the deposition cycle was repeated 350 times (p=350) so that the film accumulated to a thickness of 160 nm on the top surface of the substrate.

[0088] The bottomless deposition has been confirmed by STEM images of cross-sectional views of trenches undergoing bottomless deposition, including (a) a view of a series of film-deposited trenches, (b) an enlarged view of the top portion of one of the trenches, (c) an enlarged view of the bottom portion of the trench, and (d) an enlarged view of the sidewalls of the trench. It has been confirmed that although the trenches are not completely filled with the film, as observed in (a), the amorphous carbon polymer film is effectively flowable, wherein although the top portion of the trench is closed by the film (the top is overfilled), as observed in (b), the film flows downward and extends along the sidewalls of the trench toward the bottom of the trench, as observed in (d), without reaching the bottom of the trench, as observed in (c), thereby forming a substantially conformal (having a substantially uniform thickness along the sidewalls) and uniform film structure along the sidewalls.

[0089] Reference Example 3

[0090] An amorphous carbon polymer film was deposited on a Si substrate (having a diameter of 300 mm and a thickness of 0.7 mm) having a groove having an opening of approximately 140 to 160 nm and having a depth of approximately 2500 nm (aspect ratio of approximately 16 to 18) by a PEALD-like process in a bottomless manner under the same conditions as in Reference Example 1, except that the deposition cycle was repeated 300 times (p=300) so that the film accumulated to a thickness of 116 nm on the top surface of the substrate.

[0091] Figure 4 Schematic diagram of a STEM image of a cross-sectional view of a trench subjected to bottomless deposition (300 cycles) without ashing. Figure 4 As shown in , it is confirmed that although the groove is not completely filled with the film, the amorphous carbon polymer film is effectively flowable, wherein although the top portion of the groove is just or barely closed by the film (the top is overfilled) and although the film accumulates on the top surface of the substrate, the film flows downward and extends along the sidewall of the groove toward the bottom of the groove and slightly reaches the bottom of the groove, thereby forming a substantially conformal (having a substantially uniform thickness along the sidewall) and uniform film structure along the sidewall. If the dry etching conditions are set to have a high carbon film selectivity relative to the underlying layer (e.g., >100), a small amount of film deposition at the bottom does not interfere with further etching to form ultra-deep holes, and therefore, the deposition is still referred to as bottomless deposition. In addition, by adjusting the fluidity of the film (slightly reducing the fluidity), the flow of the film along the sidewall can be stopped before reaching the bottom.

[0092] Example 3

[0093] An amorphous carbon polymer film was deposited on a Si substrate in a bottomless manner under the same conditions as in Reference Example 3. Thereafter, ashing was continuously performed using a mixture of O2 and Ar in the same manner as in Reference Example 1, except that the RF time was shortened to 90 seconds to thin a portion of the film accumulated on the top surface of the substrate and remove the top closed portion (overfill portion) of the film in the trench to open the trench, thereby forming a spacer-like structure in the trench.

[0094] Figure 5 Schematic diagram of a STEM image of a cross-sectional view of a trench subjected to bottomless deposition (300 cycles) followed by ashing (90 seconds). Figure 5 As shown in , it is confirmed that by ashing, the overfilled top portion of the trench is effectively removed to open the top of the trench without degrading the CD integrity, thereby forming a substantially conformal (having substantially uniform thickness along the sidewall) and uniform film structure along the sidewall.

[0095] Reference Example 4

[0096] An amorphous carbon polymer film was deposited on a Si substrate in a bottomless manner under the same conditions as in Reference Example 3, except that the deposition cycle was repeated 350 times (p=350) so that the film accumulated on the top surface of the substrate to a thickness of 160 nm and completely closed the top opening of the trench (the thickness of the overfill portion above the trench was 145 nm).

[0097] Figure 6 Schematic diagram of a STEM image of a cross-sectional view of a trench subjected to bottomless deposition (350 cycles) without ashing. Figure 6 As shown in , it is confirmed that although the groove is not completely filled with the film, the amorphous carbon polymer film is effectively flowable, wherein although the top portion of the groove is closed by the film and although the film accumulates on the top surface of the substrate, the film flows downward and extends along the side walls of the groove toward the bottom of the groove in a manner similar to Reference Example 3.

[0098] Example 4

[0099] An amorphous carbon polymer film was deposited on a Si substrate in a bottomless manner under the same conditions as in Reference Example 4. Thereafter, ashing was continuously performed using a mixture of O2 and Ar in the same manner as in Reference Example 1, except that the RF time was shortened to 90 seconds to thin a portion of the film accumulated on the top surface of the substrate and remove the top closed portion (overfill portion) of the film in the trench to open the trench, thereby forming a spacer-like structure in the trench (the thickness of the overfill portion above the trench was 95 nm).

[0100] Figure 7Schematic diagram of a STEM image of a cross-sectional view of a trench subjected to bottomless deposition (350 cycles) followed by ashing (90 seconds). Figure 7 As shown in , it is confirmed that by ashing, the overfilled top portion of the trench is effectively removed to open the top of each trench without degrading the CD integrity, thereby forming a substantially conformal (having substantially uniform thickness along the sidewall) and uniform film structure along the sidewall.

[0101] Those skilled in the art will appreciate that many and various modifications may be made without departing from the spirit of the present invention. Therefore, it should be clearly understood that the form of the present invention is only illustrative and is not intended to limit the scope of the present invention.

Claims

1. A method for forming a topologically controlled layer on a patterned recessed portion of a substrate, the method comprising: (i) depositing a Si-free C-containing film having filling capability on the patterned recessed portions of the substrate by pulsed plasma assisted deposition to fill the recessed portions in a bottomless manner; and (ii) performing plasma ashing on the bottomless film filled in the recess to remove the top portion of the filling film in such a manner that only the sidewall portion of the filling film remains, Plasma ashing is performed to open the closed top portion of the recess.

2. A method for forming a topologically controlled layer on a patterned recessed portion of a substrate, the method comprising: (i) depositing a Si-free C-containing film having filling capability on the patterned recessed portions of the substrate by pulsed plasma assisted deposition to fill the recessed portions in a bottomless manner; and (ii) plasma ashing the bottomless film filled in the recess to remove a top portion of the filling film in a manner leaving only a sidewall portion of the filling film, wherein an aspect ratio of the recess is in a range of 10 to 100 and a depth of the recess is greater than 200 nm, wherein in step (i), the top portion of the filled film closes a top opening of the recess.

Images