阅读说明：本技术 用于形成热稳定有机硅聚合物膜的方法 (Method for forming thermally stable silicone polymer films ) 是由 T·J·V·布兰夸特 于 2019-07-22 设计创作，主要内容包括：一种用于形成热稳定有机硅聚合物膜的方法,包括：(i)在反应空间中使用含硅前体在衬底上沉积有机硅聚合物,其主链由硅原子构成；以及(ii)以增加Si-H键的方式在反应空间中不存在前体的情况下将在步骤(i)中沉积的所述有机硅聚合物暴露于氢等离子体,并且减小所述有机硅聚合物中的C-H键而不沉积有机硅聚合物。(A method for forming a thermally stable silicone polymer film, comprising: (i) depositing an organosilicon polymer on the substrate in the reaction space using a silicon-containing precursor, the backbone of which is composed of silicon atoms; and (ii) exposing the silicone polymer deposited in step (i) to hydrogen plasma in the absence of a precursor in the reaction space in a manner that increases Si-H bonds and reduces C-H bonds in the silicone polymer without depositing silicone polymer.)

1. A method of forming a thermally stable silicone polymer comprising:

(i) depositing an organosilicon polymer on a substrate using a silicon-containing precursor in a reaction space, the backbone of the organosilicon polymer consisting essentially or partially of silicon atoms; and

(ii) (ii) exposing the silicone polymer deposited in step (i) to hydrogen plasma in the absence of the precursor in the reaction space in a manner that increases Si-H bonds and reduces C-H bonds in the silicone polymer without depositing silicone polymer.

2. The method of claim 1, wherein step (i) comprises performing one or more cycles of Atomic Layer Deposition (ALD), and steps (i) and (ii) are repeated as step (iii) until a desired thickness of the silicone polymer is obtained.

3. The method of claim 1, wherein step (i) comprises performing Chemical Vapor Deposition (CVD), and steps (i) and (ii) are repeated as step (iii) until a desired thickness of silicone polymer is obtained.

4. The method of claim 2, wherein the ALD is Plasma Enhanced ALD (PEALD), and step (ii) is performed 2 to 10 times after performing each PEALD cycle.

5. A method according to claim 3, wherein the CVD is thermal or plasma enhanced CVD and step (ii) is carried out after each deposition of the silicone polymer in step (i) to a thickness of 1 to 50 nm.

6. The method of claim 1, wherein step (ii) comprises mixing 0.07W/cm ²To 1.4W/cm ²RF power in a range is applied to the reaction space to generate the hydrogen plasma.

7. The method of claim 1, wherein step (ii) is performed for 10 seconds to 60 seconds.

8. The process of claim 1, wherein step (ii) comprises supplying hydrogen and an inert gas into the reaction space in a ratio of hydrogen flow to total gas flow comprising hydrogen and inert gas of from 0.1 to 0.8.

9. The method of claim 1, wherein step (ii) comprises supplying hydrogen only to the reaction space to produce the hydrogen plasma.

10. The method of claim 2, further comprising, after step (iii), annealing the silicone polymer, wherein the silicone polymer exhibits substantially no shrinkage.

11. The method of claim 1, wherein the silicone polymer is comprised of polysilane, polycarbosilane, polysilazane, or polysiloxane.

12. The method of claim 1, wherein in step (ii), the hydrogen plasma is a pulsed plasma generated by applying RF power to the reaction space in a pulsed form.

13. The method of claim 1, wherein step (i) and step (ii) are performed continuously in the same reaction chamber.

Technical Field

The present invention generally relates to a method for forming a thermally stable silicone polymer film for use, for example, as a gap fill layer to fill a trench.

Background

In methods of manufacturing integrated circuits, such as those used for shallow trench isolation, intermetal dielectric layers, passivation layers, and the like, it is often desirable to fill the trenches (typically any recesses having a high aspect ratio of 1 or more) with an insulating material. However, with the miniaturization of the wiring pitch of Large Scale Integration (LSI) devices, void-free filling of high aspect ratio spaces (e.g., AR ≧ 3) becomes increasingly difficult due to limitations of existing deposition processes. In addition, even if void-free filling can be achieved, when subsequent thermal or plasma exposure, such as post-deposition treatment including plasma ashing, is performed, shrinkage of the filling material occurs, thereby generating voids. Also, void-free fills tend to have insufficient chemical resistance, such as relatively high wet etch rates.

In view of the above aspects, embodiments of the present invention provide post-deposition treatments to thermally stabilize silicone polymers. This technique can be applied not only to gap filling processes such as those disclosed in U.S. provisional application No. 62/619,569, but also to conformal film formation processes. Embodiments may address one or more of the above-described issues.

Any discussion of the problems and solutions involved in the related art has been included in the present disclosure for the sole purpose of providing a background to the invention, and should not be taken as an admission that any or all of the discussion is known at the time of filing the present application.

Disclosure of Invention

Among other things, the objects of the present invention provide a method of improving the thermal stability of organosilane polymers, which are commonly used as gap fill materials due to flowability, but are generally thermally unstable, exhibiting significant shrinkage of films composed of the polymers upon exposure to heat, such as atmospheres having temperatures of 400 ℃ or greater, such as those used in annealing or ashing processes in semiconductor manufacturing processes. Significant shrinkage of the film can interfere with the semiconductor manufacturing process. Target polymers for which improved thermal stability is desired are organosilane polymers (also referred to as "silicon-containing polymers") having a backbone consisting of silicon atoms (polysilanes), Si-C-Si backbones (polycarbosilanes), Si-N-Si backbones (polysilazanes), Si-O-Si backbones (polysiloxanes), modified backbones of any of the foregoing, or mixtures of any of the foregoing. Organosilane polymers are chemically distinct from silicon carbide (Sic), which has been highly thermally stable and has not been classified as a polymer consisting of many repeating subunits forming a chain. In some embodiments, such an organosilane polymer film is deposited on a substrate, for example, at a thickness of less than 10nm, as a first step, and then, as a second step, the organosilane polymer film is exposed to a hydrogen plasma in a manner that increases Si-H bonds and decreases C-H bonds in the organosilicon polymer, whereby polymer chains of the organosilane polymer crosslink with each other, thereby densifying the polymer and thermally stabilizing the polymer. The hydrogen plasma treatment may induce crosslinking of the polymer chains under the conditions specified in the present disclosure.

For the purpose of summarizing aspects of the invention and the advantages achieved over the related art, certain objects and advantages of the invention are described in this disclosure. Of course, it is to be understood that not necessarily all such objects or advantages may be achieved in accordance with any particular embodiment of the invention. Thus, for example, those skilled in the art will recognize that the invention may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other objects or advantages as may be taught or suggested herein.

Other aspects, features and advantages of the present invention will become apparent from the following detailed description.

Drawings

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

Figure 1A is a schematic illustration of a PEALD (plasma enhanced atomic layer deposition) apparatus for depositing a dielectric film that may be used in one embodiment of the invention.

FIG. 1B shows a schematic diagram of a precursor supply system using a flow-through system (FPS) that can be used in one embodiment of the invention.

Fig. 2 shows temperature desorption analysis data for an organosilane polymer, wherein the sample is heated and the emitted species are analyzed by mass spectrometry.

Fig. 3 is a schematic representation of the cross-linking of different polymer chains induced by H2 plasma treatment, according to an embodiment of the present invention.

Fig. 4 illustrates a process sequence consisting of a PEALD deposition cycle and an H-plasma processing process loop according to an embodiment, wherein the width of each column does not necessarily represent the actual length of time, and the elevated level of the lines in each row represents the on state, while the bottom level of the lines in each row represents the off state.

Fig. 5 is a graph illustrating a relationship between RI and RF power for H plasma processing according to an embodiment of the present invention.

Fig. 6 is a graph showing the relationship between RI and the number of deposition cycles per H plasma treatment according to an embodiment of the present invention.

Fig. 7 is a graph illustrating a relationship between RI and duration of RF power application for H plasma processing according to an embodiment of the present invention.

Fig. 8 is a graph illustrating a relationship between a Dry Etch Ratio (DER) and RI according to an embodiment of the present invention.

Fig. 9 shows a Fourier Transform Infrared (FTIR) spectrum of a gap-fill layer according to an embodiment of the present invention.

FIGS. 10 and 11 are graphs of thermal desorption gas chromatography configurations and mass spectrometry measurements showing volatile organic compound emissions for "untreated" polymers according to the comparative examples and "H2 treated" polymers according to embodiments of the present invention.

Fig. 12 shows graphs indicating thickness reduction of an untreated film according to a comparative example and thickness reduction of an H2 treated film according to an embodiment of the present invention.

Fig. 13 shows graphs indicating wet etching resistivity of the untreated film according to the comparative example and thickness reduction of the H2 treated film according to the embodiment of the present invention.

Fig. 14 shows graphs indicating thickness variation of a deposited film according to an embodiment of the present invention by annealing and thickness variation of a deposited film according to a comparative example by annealing.

FIG. 15 illustrates software indicating the use of statistical data analysis according to an embodiment of the present invention

A graph of the schematic relationship between the obtained process parameters and the RI improvement.

FIG. 16 illustrates software indicating the use of statistical data analysis according to an embodiment of the present invention

A graph of the obtained schematic relationship between the process parameter and the RI.

Fig. 17 shows STEM photographs of cross-sectional views of a gap-filled wide trench subjected to periodic hydrogen plasma treatment in (a), and a gap-filled narrow trench subjected to periodic hydrogen plasma treatment in (b), according to an embodiment of the present invention.

Detailed Description

In the present disclosure, "gas" may comprise vaporized solids and/or liquids, depending on the context, and may consist of a single gas or a mixture of gases. Also, depending on the context, the article "a" refers to one species or a genus comprising a plurality of species. In the present disclosure, the process gas introduced into the reaction chamber through the showerhead may comprise, consist essentially of, or consist of a silicon-containing precursor and an additive gas. The additive gas may include a reaction gas for nitriding and/or carbonizing the precursor and an inert gas (e.g., an inert gas) for exciting the precursor when RF power is applied to the additive gas. The inert gas may be fed to the reaction chamber as a carrier gas and/or a diluent gas. In the present disclosure, no reaction gas for oxidizing the precursor is used. Furthermore, in some embodiments, no reactive gas is used, and only an inert gas (as a carrier gas and/or a diluent gas) is used. The precursor and additive gases may be introduced into the reaction space as a mixed gas or separately. The precursor may be introduced using a carrier gas such as a noble gas. Gases other than process gases, i.e. gases introduced without passing through the showerhead, may be used, for example, to seal the reaction space, which contains a sealing gas such as a noble gas. In some embodiments, the term "precursor" generally refers to a compound that participates in a chemical reaction that produces another compound, and particularly refers to a compound that constitutes the membrane matrix or the main framework of the membrane, while the term "reactant" refers to a compound that is not an activated precursor of a precursor, modifies a precursor, or catalyzes a reaction of a precursor, wherein the reactant can provide an element (e.g., N, C) to and become part of the membrane matrix when RF power is applied. The term "inert gas" refers to a gas that excites the precursor when RF power is applied, but unlike the reactants, does not become part of the film-forming substrate.

In some embodiments, a "film" refers to a layer that covers the entire target or associated surface, or simply a layer that covers the target or associated surface, substantially free of pinholes, extending continuously in a direction perpendicular to the thickness direction. In some embodiments, "layer" refers to a structure formed on a surface having a certain thickness, or synonym for a film or non-film structure. A film or layer may be comprised of a discrete single film or layer or of multiple films or layers having certain characteristics, and the boundaries between adjacent films or layers may or may not be transparent and may be established based on physical, chemical, and/or any other characteristics, forming processes or sequences, and/or the function or purpose of the adjacent films or layers. Further, in the present disclosure, since the operable range may be determined based on conventional work, any two numbers of a variable may constitute the operable range of the variable, and any range indicated may include or exclude endpoints. Additionally, any values for the indicated variables (whether they are indicated with "about" or not) can refer to exact or approximate values and include equivalents and, in some embodiments, can refer to mean, median, representative, majority, and the like. Further, in this disclosure, in some embodiments, the terms "consisting of … …" and "having" independently mean "typically or broadly comprising," including, "" consisting essentially of … …, "or" consisting of … …. In the present disclosure, in some embodiments, any defined meaning does not necessarily exclude a common and customary meaning.

In the present disclosure, "continuous" means, in some embodiments, without breaking vacuum, without breaking with time lines, without any material insertion steps, without changing process conditions, immediately thereafter, as a next step, or without inserting a discrete physical or chemical structure between two structures in addition to the two structures.

In some embodiments, the term "precursor" refers generally to a compound that participates in a chemical reaction that produces another compound, and in particular, to a compound that constitutes the membrane matrix or the main framework of the membrane, while the term "reactant" refers to a compound that activates, modifies, or catalyzes a reaction of a precursor.

In the present disclosure, the recesses between adjacent protrusion structures and any other recess pattern are referred to as "grooves". That is, the trench is any recess pattern that includes holes/vias, and which in some embodiments has a width of about 20nm to about 100nm (typically about 30nm to about 50nm) (where when the trench has substantially the same length as the width, it is referred to as a hole/via, and has a diameter of about 20nm to about 100nm), 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). The appropriate dimensions of the trenches may vary depending on process conditions, film composition, intended application, and the like.

In some embodiments, a method of forming a thermally stable silicone polymer, comprises: (i) depositing an organosilicon polymer on the substrate in the reaction space using a silicon-containing precursor, the backbone of which is composed of silicon atoms; and (ii) exposing the silicone polymer deposited in step (i) to hydrogen plasma in the absence of a precursor in the reaction space in a manner that increases Si-H bonds and reduces C-H bonds in the silicone polymer without depositing silicone polymer.

In some embodiments, in step (i), the target organosilane polymer is thermally unstable, wherein the term "thermally unstable" refers to the property of a film to exhibit 10% or greater shrinkage as measured when placed at a temperature of 450 ℃ for five minutes in an inert gas (e.g., inert gas, such as Ar) atmosphere or equivalent conditions thereto, such as annealing or ashing conditions. . The term "thermally stable" means that the film is not "thermally unstable" (exhibiting a shrinkage of less than 10%, as measured in the same manner above), typically exhibits a shrinkage of 5% or less, and preferably exhibits substantially no shrinkage (e.g., less than 10%, 5%, 1%, or substantially 0%).

In some embodiments, the target organosilane polymer is comprised of a polysilane, polycarbosilane, polysilazane, or polysiloxane. In some embodiments, the target organosilane polymer is a flowable silicon-containing polymer that is used, for example, as a gap fill layer to fill a trench. For example, the flowable silicon-containing polymer disclosed in U.S. provisional application No. 62/619,569, the disclosure of which is incorporated herein by reference in its entirety, can be used as the target organosilane polymer that discloses a PEALD-like process ("PEALD-like process" includes PEALD formulations, e.g., feed/purge/plasma strike/purge, where purging after feeding spontaneously shortens to retain a high partial pressure of the precursor during plasma breakdown, which is clearly distinguished from ALD chemistry or mechanism). In some embodiments, the target organosilane polymer comprises a conformal film (with 80% or more conformality). E.g. H ₂The plasma can uniformly improve the quality (e.g., thermal stability) of the film deposited on the top surface, trench sidewalls, and trench bottom, while H ₂/Ar plasma or H ₂the/He plasma can improve the quality (e.g., thermal stability) of the films deposited on the top and bottom surfaces of the trench more effectively than the quality (e.g., thermal stability) of the films deposited on the trench sidewalls due to the contribution of the Ar or He ions to the heavy ion bombardment. The plasma is preferably a direct plasma (generated in the reaction chamber with capacitively coupled parallel electrodes). For remote plasmas, the improvement can be topologically uniform, but the process is less efficient than direct plasmas.

The target organosilane polymer can be deposited not only by Plasma Enhanced Atomic Layer Deposition (PEALD), but also by Plasma Enhanced Chemical Vapor Deposition (PECVD) using continuous plasma or pulsed plasma. Additionally, such polymers can also be thermally formed by thermal CVD (including pulsed CVD) and thermal ALD with suitable chemistries/catalysts.

Step (ii) is not part of the deposition step (i), i.e. the plasma is used to reconstitute the existing polymer, without depositing or forming a new polymer layer. In step (ii), no precursor (nor reactant) is fed to the reaction space, or no unreacted precursor adsorbs onto the surface of the substrate, such that substantially no new film is formed on said surface of said substrate. In addition, in step (ii), at least one gas used in step (i) other than the precursor and/or at least one gas not used in step (i) is not used to perform the hydrogen plasma treatment. In an ALD process comprising a plurality of repeated deposition cycles to deposit a monolayer or at least an equal amount of flowable material, step (i) consists of one or more deposition cycles, and step (ii) is performed after each step (i). The thickness of the film deposited in step (i) is less than 10nm, typically less than 5nm, prior to performing step (ii), such that the film is fully reformed in the thickness direction by step (ii). In some embodiments, step (i) comprises performing one or more cycles (e.g., 2 to 10 cycles) of Plasma Enhanced Atomic Layer Deposition (PEALD) once per step (ii), and steps (i) and (ii) are repeated as step (iii) until a desired thickness (e.g., about 20nm to about 100nm) of the silicone polymer is obtained.

In some embodiments, step (i) and step (ii) are performed continuously in the same reaction chamber. In the present disclosure, "continuously" means without interrupting the vacuum, without line interruption over time, without any material insertion step, without changing the process conditions, immediately thereafter, as a next step, or without inserting a discrete physical or chemical structure between two structures in addition to the two structures, depending on the embodiment.

In some embodiments, step (ii) comprises mixing 0.07W/cm ²To 1.4W/cm ²(e.g., 0.14 to 0.7W/cm) ²) RF power in a range is applied to the reaction space to generate a hydrogen plasma. In some embodiments, step (ii) is performed for 5 seconds to 60 seconds (e.g., 10 seconds to 30 seconds). In some embodiments, step (ii) comprises supplying hydrogen and an inert gas to the reaction space in a ratio of hydrogen flow to total gas flow comprising hydrogen of from 0.1 to 0.9 (e.g., from 0.5 to 0.8). In thatIn some embodiments, step (ii) comprises supplying hydrogen gas only to the reaction space to generate the hydrogen plasma.

In some embodiments, in step (ii), the hydrogen plasma is a pulsed plasma generated by applying RF power to the reaction space at intervals of about 10 milliseconds to about 500 milliseconds (e.g., about 50 milliseconds to about 200 milliseconds).

The present invention is explained in more detail below using examples, but the present invention is not intended to be limited to the examples.

As discussed above, the material to be reformed is an organosilane polymer not considered to be composed of silicon carbide (SiC), which is generally thermally stable and non-flowable. In some embodiments, the organosilane polymer has a polysilane-based structure, which may or may not be flowable, but low thermal stability. Although both silicon carbide and silicon-containing polymers contain silicon atoms and carbon atoms, silicon-containing polymers have lower density and are less heat resistant than silicon carbide, and therefore, silicon-containing polymers are less thermally stable than silicon carbide and are susceptible to, for example, shrinkage and dry etching. The silicon-containing polymer properties are strongly dependent on the state of cross-linking of the polymer, which is crucial for the thermal stability of the polymer. Hydrogen plasma treatment can induce crosslinking, which has a positive effect on film properties (e.g., thermal stability and dry etch resistance).

Fig. 3 is a schematic representation of the cross-linking of different polymer chains induced by H2 plasma treatment, according to an embodiment of the present invention. Despite the high degree of randomness present in plasma polymerization, as shown in fig. 3, the different polymer chains (which may be the same chains) are cross-linked by hydrogen plasma treatment, thereby promoting densification (increasing RI), and improving thermal stability and resistance to dry etching or other chemical treatments.

In some embodiments, because the silicon-containing polymer deposition need not be flowable or bottom-up deposition, the process parameters for depositing the silicon-containing polymer may be selected and set wider than those for bottom-up deposition, such as those disclosed in U.S. provisional application No. 62/619,569. Since the parameters and set points for depositing SiC may be those shown in table 1 below, the silicon-containing polymer may be formed under conditions having one or more set points different from those shown in table 1, where "SUS temperature" (susceptor temperature) and "purge" (purge after precursor feed) may be the most influential parameters. In table 1, "He total amount" means a total flow rate of He gas including He carrier gas, He sealing gas, He diluting gas, etc., a "gap" means a gap between the capacitively-coupled parallel electrodes, a "pressure" means a pressure of the reaction space, and a "feeding" means feeding of the precursor. Such conditions are readily provided by those skilled in the art, in light of the entire disclosure and disclosure of U.S. provisional application No. 62/619,569, which is incorporated herein by reference in its entirety, to optimize process conditions as the subject of routine experimentation.

TABLE 1 (values are approximations)

The organosilane polymer is then subjected to a hydrogen plasma treatment to improve thermal stability. Fig. 4 illustrates a process sequence consisting of a PEALD deposition cycle and an H-plasma treatment process according to one embodiment, where the width of each column does not necessarily represent the actual length of time, and the elevated level of the lines in each row represents the on state, while the bottom level of the lines in each row represents the off state. In this procedure, "gas stabilization 1" refers to a first gas stabilization step performed before each deposition step, in which feeding of a plasma generation gas (e.g., He) is started without feeding a precursor and without applying RF power. "Depo" refers to a deposition step comprising one or more deposition cycles each depositing a monolayer or at least an equal amount of flowable material, wherein each cycle consists of feeding precursor, purging, applying RF power, and purging (in this sequence, the cycle repeats once, i.e., two cycles are performed, although the number of cycles is not so limited and any suitable number of cycles may be performed).

Subsequently, a hydrogen plasma treatment step is started. In this process, "gas stabilization 2" refers to a second gas stabilization step performed before the hydrogen plasma treatment step, in which the feeding of the plasma generation gas (e.g., He) is stopped, while the feeding of hydrogen gas and another plasma generation gas (e.g., Ar) are started without feeding the precursor and without applying RF power. In "H-treatment," which refers to a hydrogen plasma treatment step, RF power is applied in the absence of any precursor. Albeit H ₂the/Ar plasma is more stable than H in terms of improved thermal stability (induced polymer crosslinking) ₂the/He plasma is more efficient and H2/He plasma can be used. Likewise, H may be used alone ₂Plasma is generated. In some embodiments, the machinable flow ratio of He to total plasma generating gas (including He and/or Ar) is not limited, as long as there is no arc and the plasma is stable, and the machinable flow ratio is highly hardware dependent. In some embodiments, the hydrogen plasma treatment is performed under the conditions shown in table 2 below in a manner similar to that shown in fig. 4.

Table 2 (values are approximations)

In the above, "RF power (for 300mm wafers)" can be converted to units of W/cm for different size wafers using continuous or pulsed plasma in PEALD-like processes and PECVD ². In the above, "thickness of deposited organosilane polymer exposed to H2 plasma" refers to the thickness of the polymer on the top surface of the substrate.

In some embodiments, the deposition step and the hydrogen plasma treatment are performed sequentially in the same reaction chamber. For example, fig. 1A is a schematic illustration of a PEALD (plasma enhanced atomic layer deposition) apparatus for depositing a dielectric film that may be used in one embodiment of the invention. In this figure, a plasma is ignited between a pair of electrically conductive plate electrodes 4, 2 connected in parallel and facing each other in the interior 11 (reaction zone) of the reaction chamber 3 by applying HRF power (50Hz or 2GHz)25 to one side and electrically grounding the other side 12. A temperature regulator is provided in the lower stage 2 (lower electrode), and the temperature of the substrate 1 placed thereon is kept constant at a specified temperature. The upper electrode 4 also acts as a shower plate, and the plasma generating gas (and the diluent gas if present) and the precursor gas (with the carrier gas if present) are introduced into the reaction chamber 3 through the gas line 21 and the gas line 22, respectively, and pass through the shower plate 4. In addition, in the reaction chamber 3, a ring pipe 13 with an exhaust line 7 is provided, through which the gases in the interior 11 of the reaction chamber 3 are exhausted. In addition, the transfer chamber 5 disposed below the reaction chamber 3 is provided with a seal gas line 24 to introduce a seal gas into the interior 11 of the reaction chamber 3 through the interior 16 (transfer zone) of the transfer chamber 5, wherein a partition plate 14 for partitioning the reaction zone and the transfer zone is provided (this figure omits a gate valve through which a wafer is transferred into the transfer chamber 5 or transferred out of the transfer chamber 5). The transfer chamber is further provided with an exhaust line 6. In some embodiments, the deposition and surface treatment of the multielement film 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 atmosphere.

The continuous flow of carrier gas can be achieved using a flow through system (FPS) in which the carrier gas line is provided with a by-pass line with a precursor reservoir (bottle) and the main and by-pass lines are switched, wherein the by-pass line is closed when the carrier gas is intended to be fed only to the reaction chamber and the main line is closed when the carrier gas and the precursor gas are intended to be fed to the reaction chamber and the carrier gas flows through the by-pass line and 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 pulses by switching the main and bypass lines. FIG. 1B illustrates a precursor supply system using a flow-through system (FPS) according to one embodiment of the invention (black valves indicate that the valves are closed). As shown in (a) of fig. 1B, when the precursor is fed to a reaction chamber (not shown), first, a carrier gas such as Ar (or He) flows through a gas line having valves B and c, and then enters a bottle (reservoir) 20. The carrier gas flows out of the bottle 20 while carrying a precursor gas corresponding to the vapor pressure inside the bottle 20, and flows through a gas line having valves f and e, and then is fed to the reaction chamber together with the precursor. In the above, the valves a and d are closed. When only the carrier gas (inert gas) is fed to the reaction chamber, as shown in (B) of fig. 1B, the carrier gas flows through the gas line having the valve a while bypassing the bottle 20. In the above, the valves b, c, d, e and f are closed.

After completion of the deposition step (which may consist of, for example, 2 to 6 cycles of PEALD), the hydrogen plasma treatment step is started in a similar manner to the deposition step, but without feeding precursor gases and adjusting the process parameters for the hydrogen plasma treatment.

The skilled artisan will appreciate that the apparatus includes one or more controllers (not shown) programmed or otherwise configured to enable deposition and reactor cleaning processes described elsewhere herein. Those skilled in the art will appreciate that the controller is in communication with various power supplies, heating systems, pumps, robotic devices, and gas flow controllers or valves of the reactor.

In some embodiments, a dual chamber reactor (for processing two sections or compartments of a wafer disposed proximate to each other) may be used in which the reactant gas and the inert gas may be supplied through a shared line and the precursor gas through an unshared line.

Films with fill capability may be applied to a variety of semiconductor devices including, but not limited to, cell isolation, self-aligned vias, dummy gates (replacing current poly Si), reverse tone patterning, PC RAM isolation, cut hard masks, and DRAM Storage Node Contact (SNC) isolation in 3D cross point memory devices.

Examples of the invention

In the following examples, where conditions and/or structures are not specified, such conditions and/or structures can be readily provided by one of ordinary skill in the art in light of the present disclosure following routine experimentation. The skilled artisan will appreciate that the apparatus used in the examples includes a controller(s) (not shown) programmed or otherwise configured to enable deposition and reactor cleaning processes described elsewhere herein. As will be appreciated by those skilled in the art, the controller(s) are in communication with the gas flow controllers or valves of the various power supplies, heating systems, pumps, robotic devices, and reactors.

Example 1

Using the apparatus shown in fig. 1A and the gas supply system (FPS) shown in fig. 1B, organosilicon polymer was deposited on Si substrates (having a diameter of 300mm and a thickness of 0.7 mm) having narrow trenches of about 30nm width and wide trenches of about 75nm width, the trenches having a depth of about 70nm, by a PEALD-like process ("PEALD-like process" including PEALD recipes such as feed/purge/plasma strike/purge, where the purge after feed spontaneously shortens to leave a high partial pressure of precursor during plasma strike, which PEALD-like process is significantly different from ALD chemistry or mechanism), under the conditions shown in table 3 below. A carrier gas (with a flow rate of 0.1slpm) was used to feed the precursor (dimethyldivinylsilane as the volatile alkylsilane precursor) to the reaction chamber. However, due to the high vapor pressure of the precursor, no carrier gas is required. In this example, the small mass flow of carrier gas is used only as a precaution against condensation of the precursor in the line. If the line is sufficiently heated, then no carrier gas need be used. Furthermore, although the dry He flow is used to make plasma ignition easier and more stable, the dry He flow can be eliminated as long as the plasma is ignited.

The deposition cycle defined in table 3 was repeated four times as a deposition step, and then, under the conditions shown in table 4 below, H plasma treatment was performed as a post-deposition treatment ("examples 1-1", "examples 1-2" and "examples 1-3") in a similar manner to that shown in fig. 4, wherein such modified deposition cycle was repeated (i.e., from the deposition cycle and post-deposition point)Physical structuring) until the deposited film completely fills the trench and further accumulates thereon to form a flat top surface. In the deposition process described above, a periodic H plasma treatment was performed to anneal (at 450 ℃ C. under N) as shown in Table 4 ₂30 minutes in an atmosphere), RI (e.g., refractive index measured using a wavelength of 633 nm), and dry etch rate ("DER") characteristics (e.g., using CF) ₄/O ₂/Ar as etching gas mixture at 20 ℃ at 8Pa for 15 seconds) provides some benefits.

Table 3 (values are approximations)

Table 4 (values are approximations)

In table 4, "D/T ratio" means a ratio of a deposition cycle to a post-deposition treatment, "gas stabilization 1" and "gas stabilization 2" correspond to "gas stabilization 1" and "gas stabilization 2" in fig. 4, respectively.

Also, as a comparative example ("comparative example 1" in table 4), a flowable film was deposited without post-deposition treatment under the conditions shown in table 4 until the deposited film completely filled the trench and further accumulated thereon, forming a flat top surface.

As shown in table 4, by performing the H plasma treatment as the post-deposition treatment, the RI of the film was improved, the dry etching rate was decreased (resistance to dry etching was high), and the shrinkage rate by annealing was significantly decreased or completely suppressed. In some embodiments, 50 to 500W (0.07 to 0.71W/cm) may be used ²) The RF power of (1) is continued for 10 to 180 seconds to effectively perform the H plasma process.

FIG. 9 illustrates a gap through a PEALD-like processFourier Transform Infrared (FTIR) spectra of the packed layers. As shown in fig. 9, the deposited material ("untreated") contained Si-C bonds and C-H bonds, confirming that the material was a SiC-based material (silicone polymer), and by the H plasma treatment ("H2 treatment"), the C-H bonds were significantly reduced, while the Si-H bonds in the silicone polymer were significantly increased, increasing the cross-linked polymer chains, and thermally stabilizing the silicone polymer. FIGS. 10 and 11 are graphs of thermal desorption gas chromatography and mass spectrometry detection showing the emission of volatile organic compounds from "untreated" polymer and "H2 treated" polymer. As shown in fig. 10 and 11, the untreated polymer showed significant degassing of CxHy components, especially C ₃H ₅Degassing, which starts at about 400 ℃, increases sharply at about 600 ℃, and peaks at about 700 ℃, resulting in significant densification (shrinkage) of the film, and the untreated polymer shows significant degassing of the Si component, which starts at about 400 ℃, increases sharply at about 500 ℃, and peaks at about 600 ℃, resulting in loss of Si due to evaporation from the film. In contrast, in the "H2-treated" polymer, Si evaporation was substantially completely suppressed even at high temperatures (e.g., 500 ℃ or more), and C was substantially completely suppressed even at high temperatures (e.g., 600 ℃ or more) ₃H ₅To prevent the film from shrinking.

Fig. 17 shows STEM photographs of cross-sectional views of a wide trench subjected to gap filling by the periodic hydrogen plasma treatment in (a) and a narrow trench subjected to gap filling by the periodic hydrogen plasma treatment in (b). As shown in fig. 17, by performing the periodic hydrogen plasma treatment, substantially no shrinkage of the deposited film was observed when annealing was performed (example 1-1).

Example 2

In comparative example 2, a flowable film was deposited by a PEALD-like process in a similar manner as in comparative example 1. In example 2, flowable films were deposited by a PEALD-like process (i.e., deposition combined with periodic H plasma treatment) in a similar manner as in example 1-1 to provide some benefits in terms of RI and dry etch rate characteristics, and O content, shown in table 5 below.

Table 5 (values are approximations)

As shown in table 5, by performing the H plasma treatment, the cross-linking of the polymer chains may progress and the different chains may be more tightly bound to each other, thereby advancing the densification of the polymer. Since RI is most commonly related to material density, as shown in table 5, both density and RI are increased by H plasma treatment. Also, the H plasma treatment improves chemical resistance to dry etching.

Example 3

In comparative example 3, a flowable film was deposited by a PEALD-like process in a similar manner as in comparative example 1. In example 3, flowable films were deposited by a PEALD-like process (i.e., deposition combined with periodic H plasma treatment) in a similar manner as in examples 1-1, in order to provide a high degree of thermal stability to the deposited films. The film was annealed at a temperature of 450 ℃ under a pressure of 1,000Pa for 0 min (i.e. no annealing), 5 min and 30 min in an Ar atmosphere.

Fig. 14 shows graphs indicating thickness variations of the deposited film of example 3 by annealing and those of the deposited film of comparative example 3 by annealing, in which annealing was performed. As shown in fig. 14, the untreated film ("comparative 3") shrunk significantly, with the thickness of the film reduced by about 50% at 5 minutes anneal and reached about 75% at 30 minutes, while surprisingly the untreated film ("example 3") did not shrink even at 30 minutes anneal, that is, no film shrinkage was observed even at 30 minutes anneal, indicating a very high degree of thermal stability.

Typically, temperatures below 400 ℃, the shrinkage of the untreated film is saturated, wherein the thickness of the film will be reduced by about 30% and additional annealing will not result in further shrinkage. However, the shrinkage of untreated films typically becomes unsaturated at temperatures of 400 ℃ or higher. That is, if the film is subjected to an annealing time long enough, the untreated film will eventually evaporate completely, leaving only a thin residue.

Fig. 2 shows temperature desorption analysis data for an organosilane polymer, wherein the sample is heated and the expelled species is analyzed by mass spectrometry. The X-axis indicates the mass detected, which can then be attributed to the species excreted (e.g., mass 2 indicates H ₂And quality 15 indicates CH ₃). The Y-axis on the left indicates the temperature of the sample, showing that a particular species is being excreted at a particular temperature. The Z-axis on the right shows the relationship between the intensity of the emitted signal (i.e. indicating how much emission is) and the grey scale contrast density (gradient), which shows the intensity gradient from the limit of detection (white/light-no emission) to a large number of emissions (dark). It should be noted that the raw data is colored and the intensity gradient does not show yellow/green emission, blue emission begins, and red mass emission. However, the gray scale of red appears lighter than blue, and in fig. 2, in each emission-detected vertically distinct dark region, the slightly lighter gray region in the center surrounded by the dark gray region is initially red, indicating that the center shows higher emission than the surrounding regions. This information is quite qualitative, but clearly shows that at temperatures of about 400 ℃ or higher, most of the components of the polymer begin to be significantly removed, that is, the polymer begins to shrink at temperatures of about 400 ℃ or higher, and continues irreversibly. The polymer deposited without periodic H plasma treatment is highly thermally unstable.

In contrast, as shown in fig. 14, the polymer deposited in combination with the periodic H plasma treatment (example 3) exhibited high thermal stability, exhibited substantially no component decomposition or outgassing upon annealing at 450 ℃, indicating that the polymer crosslinked together, densified, and formed a stable matrix with resistance to thermal degradation.

Table 6 below shows the mass loss (%) and shrinkage (%) for the untreated membrane and the H2 treated membrane. As shown in the table, H ₂The plasma treatment can effectively induce crosslinking and improve the thermal stability of the polysilane-based film.

Table 6 (values are approximations)

	Shrinkage (%)	Mass loss (%)
			Untreated	55	75
H2 treatment	0	10

Example 4

In comparative example 4 ("untreated"), a flowable film was deposited by a PEALD-like process in a similar manner as in comparative example 1. In example 4 ("H2 treatment"), a flowable film was deposited by a PEALD-like process in a manner similar to that in example 1-1 (i.e., deposition combined with periodic H plasma treatment) (. the film was subjected to post-deposition annealing/ashing at a temperature of 200 ℃ as a common condition at a pressure of 400Pa for 2 minutes and under the specific conditions shown in table 7 below, to evaluate the annealing/ashing effect on the untreated polymer and the H2 treated polymer.

Table 7 (values are approximations)

	Polymer and method of making same	RF power (W)	Ar(slpm)	N 2(slpm)	H 2(slpm)
						Comparative example 4	Untreated	-	1	-	-
Example 4-1	H2 treatment	200	-	1	-
						Example 4-2	H2 treatment	200	-	-	1
Examples 4 to 3	H2 treatment	200	-	0.5	0.5

Fig. 12 shows a graph indicating a thickness reduction of each film, and fig. 13 shows a graph indicating a wet etching resistivity of each film. As shown in FIGS. 12 and 13, the untreated film was subjected to all annealing/ashing, especially N ₂/H ₂The severe effect of ashing, which acts synergistically against wet etch degradation (fig. 13). This may be due to the cleavage of the polysilane-based chain moiety and passing of N ₂Plasma N-terminated, forming a poor quality nitride-like film, and H ₂The plasma promotes the reaction. In contrast, the H2 treated film was significantly more resistant to annealing/ashing.

Examples 5 to 7

In example 5, a flowable film was deposited by a PEALD-like process in a manner similar to that in example 1-1 (i.e., deposition combined with periodic H plasma treatment), but the RF power for the H plasma treatment was varied as shown in fig. 5. In example 6, flowable films were deposited by a PEALD-like process in a manner similar to that in examples 1-1 (i.e., deposition combined with periodic H-plasma treatment), but the number of deposition cycles per H-plasma treatment varied as shown in fig. 6. In example 7, a flowable film was deposited by a PEALD-like process in a manner similar to that in example 1-1 (i.e., deposition combined with periodic H plasma treatment), but the duration of RF power application for the H plasma treatment was varied as shown in fig. 7. The quality of each of the resulting films was evaluated according to RI at 633 nm. The degree of cure of the polymer was evaluated using the RI value, where the higher the RI, the higher the degree of cure is expected (the higher the density becomes). The results are shown in FIGS. 5 to 7.

Fig. 5 is a graph showing the relationship between RI and RF power for H plasma processing, showing that RI becomes higher as RF power is higher. Fig. 6 is a graph showing the relationship between RI and the number of deposition cycles per H plasma treatment, showing that RI becomes lower as the number of deposition cycles per H plasma treatment is larger. Fig. 7 is a graph showing the relationship between RI and the duration of RF power application for H plasma processing, showing that RI becomes higher the longer the duration of RF power application. Thus, by manipulating the H plasma processing conditions using process parameters, material quality can be adjusted. The skilled person may find suitable conditions for the intended application or use of the obtained film by routine experimentation based on the disclosure of the present application.

The obtained film was further investigated to determine the relationship between the Dry Etching Rate Ratio (DERR) and RI. FIG. 8 is a graph showing the relationship between dry etch rate ratio (DER), calculated by dividing the absolute Dry Etch Rate (DER) of the film by the absolute DER of PECVD silicon carbide, using CF at 8Pa at 20 deg.C, and RI ₄/O ₂DER was measured as an etching gas mixture for 15 seconds. As shown in fig. 8, DERR and RI are highly correlated, and in general, the higher the RI, the lower the DER becomes

It will be understood by those skilled in the art that many different modifications may be made without departing from the spirit of the invention. Accordingly, it should be clearly understood that the forms of the present invention are illustrative only and are not intended to limit the scope of the present invention.