Vapor deposition of organic film

Abstract

To provide a deposition reactor and a method for depositing organic films by vapor deposition.SOLUTION: In a method for vaporizing an organic reactant at a first temperature 10, transporting the vapor 20 to a reaction chamber containing a substrate, vapor-phase depositing an organic film 30 so as to maintain the substrate at a temperature below the vaporization temperature, alternating contact of the substrate with the organic reactant and the second reactant in a sequential deposition procedure results in bottom-up filling of voids and trenches with an organic film in a manner that is otherwise difficult to achieve.SELECTED DRAWING: Figure 1A

Description

[Technical Field]

[0001] REFERENCE TO RELATED APPLICATIONS This application is a continuation-in-part of U.S. patent application Ser. No. 14 / 879,962, filed Oct. 9, 2015.

[0002] Field The present invention relates to a method for forming organic thin films by vapor deposition. [Background technology]

[0003] Organic thin films have valuable optical, thermal, electrical, and mechanical properties and are widely used in the electronics, medical engineering, defense, pharmaceutical, and micro- and nanotechnology industries. Polymers in the microelectronics and photonics industries include, among others, photon- or electron-curable / degradable polymers for lithographic patterning and polyimides for packaging, interlayer dielectrics, and flexible printed circuit boards. Norrman et al., Annual Reports on the Progress of Chemistry, Section C, 2005, 101, 174-201.

[0004] Polyimide films, in particular, are valuable due to their thermal stability and resistance to mechanical stress and chemicals. Polyimide thin films can be used as a starting point for amorphous carbon films or layers in semiconductor applications, which are required for future V-NAND structures. Polyimide films can be used, for example, as anti-reflective layers to improve pattern definition and reduce misregistration in lithography steps, as layers in multiple patterning (e.g., SDDP, SDQP), as insulating materials for interlayer dielectrics, or as gate dielectrics in all-organic thin-film transistors.

[0005] Thin polymer films have traditionally been fabricated using spin-coating techniques. Spin-coating involves coating a rotating disk with a liquid material and then sintering the liquid to form highly functional polymer films. However, the tailoring of spin-coated films is limited for several reasons. For example, the formation of uniform thin films on a substrate can be difficult to control, in part due to the viscosity of the source liquid, and it can be difficult to fill gaps with very small feature dimensions (e.g., trenches or gaps between metal lines) without creating voids after curing. Additionally, spin-coating over topography that is high relative to the desired layer thickness can result in discontinuous or non-conformal deposition. As semiconductor chip sizes continue to shrink, thinner, stronger films with more tailorable morphologies are needed.

[0006] Recently, vapor phase deposition processes such as chemical vapor deposition (CVD), vapor phase polymerization (VDP), and molecular layer deposition (MLD), as well as sequential deposition processes such as atomic layer deposition (ALD) and cyclic CVD, have been applied to the formation of polymer thin films. In CVD, films are deposited when reactants react on a substrate surface. One or more reactant gases are supplied to one or more substrates in a reaction chamber. In thermal CVD, reactant gases react with each other on a hot substrate to form a thin film, with the growth rate affected by temperature and the amount of reactant supplied. In plasma-enhanced CVD, one or more reactants can be activated in a remote plasma generator or in situ. In ALD, films are built up through self-saturating surface reactions that occur in a cyclical fashion. Alternating vapor-phase reactants are supplied to a substrate or wafer to form a thin film of material on the wafer. In a typical process, one reactant adsorbs to the wafer in a self-limiting process. A different reactant is subsequently pulsed to react with the adsorbed species of the first reactant to form no more than a monolayer of the desired material. Repeated growth cycles produce thicker films until the target thickness is achieved. Plasma-enhanced variants of ALD, as well as ALD / CVD hybrid processes (e.g., where some overlap of reactants is allowed), are also known. Summary of the Invention

[0007] In one embodiment, a method is provided for depositing an organic film by vapor deposition. The method includes vaporizing a first organic reactant in a vaporizer at a temperature A to form a first reactant vapor. A substrate in a reaction space is exposed to the first reactant vapor at a temperature B, where temperature B is less than temperature A at which the first organic reactant was vaporized. An organic film is deposited on the substrate.

[0008] In some embodiments, the organic film comprises a polymer. In some embodiments, the polymer is a polyimide. In some embodiments, the organic film comprises a polyamic acid. In some embodiments, the polyamic acid is further converted to a polyimide. In some embodiments, the first organic reactant is a solid at room temperature and atmospheric pressure. In some embodiments, the first organic reactant is an acid dianhydride, more particularly in some embodiments, PMDA.

[0009] The ratio of temperature A to temperature B, expressed in Kelvin, is greater than 1. In some embodiments, the ratio of temperature A to temperature B, expressed in Kelvin, can be less than 1.8, between about 1 and 1.25, between about 1.01 and 1.10, and / or between any of the other aforementioned values.

[0010] In some embodiments, temperature A may be above 120° C., below 200° C., between about 120° C. and 250° C., between about 140° C. and 190° C., and / or between any of the other aforementioned values.

[0011] In some embodiments, temperature B is between about 5° C. and about 50° C. lower than temperature A, between about 10° C. and about 30° C. lower than temperature A, and / or between any of the other aforementioned values.

[0012] In some embodiments, temperature B may be above 20° C., below 250° C., between about 20° C. and 250° C., between about 100° C. and 200° C., between about 120° C. and 180° C., and / or any of the other values ​​recited above.

[0013] In some embodiments, the method further includes removing excess first reactant vapor from contact with the substrate. The substrate is then exposed to a second reactant such that the first reactant vapor and the second reactant vapor do not substantially mix, and the excess second reactant is removed from contact with the substrate. In some embodiments, the steps of exposing the substrate to the first reactant vapor and exposing the substrate to the second reactant are repeated in multiple cycles such that the first reactant vapor and the second reactant vapor do not substantially mix. In some embodiments, the second reactant is a diamine, and more particularly in some embodiments, 1,6-diaminohexane (DAH). In some embodiments, each of removing excess first reactant vapor and removing excess second reactant vapor occurs for a period of time greater than 1 second, less than 10 seconds, between about 1 second and about 10 seconds, and / or between any of the other values ​​recited above.

[0014] In some embodiments, vapor of the first reactant is transported from the vaporizer to the reaction space through a gas line when it contacts the substrate. In some embodiments, the gas line is at a temperature C, which is higher than the temperature A at which the first organic reactant was vaporized.

[0015] In some embodiments, the substrate includes a non-planar topography, and the deposited organic film includes forming a first thickness over a lower feature of the substrate and depositing a second thickness over an upper region area of ​​the substrate, the first thickness being greater than the second thickness.

[0016] In another aspect, a method for controlling the flatness of a deposited organic film is provided. The method includes vaporizing a first organic reactant in a vaporizer at temperature A to form a first reactant vapor; exposing a substrate to the first reactant vapor in a reaction space at temperature B, which is lower than temperature A; and removing excess first reactant vapor from contact with the substrate for a period of time, wherein decreasing the period of time increases the flatness of the deposited organic film. In some embodiments, the deposited organic film has a thickness non-uniformity (1σ) of less than about 20%, less than about 10%, less than about 5%, less than about 2%, less than about 1%, and less than about 0.5%. In some embodiments, the substrate is a semiconductor wafer, such as a 200 mm or 300 mm silicon wafer, or a glass substrate.

[0017] In some embodiments, the method further includes exposing the substrate to the second reactant such that the vapor of the first reactant and the second reactant do not substantially intermix, removing excess second reactant from contact with the substrate, and repeating the exposing the substrate to the vapor of the first reactant and the exposing the substrate to the second reactant for a plurality of cycles such that the vapor of the first reactant and the second reactant do not substantially intermix.

[0018] In another aspect, an apparatus for organic film deposition includes a vessel configured to vaporize a first organic reactant to form a first reactant vapor, a reaction space configured to receive a substrate and in selective fluid communication with the vessel, and a control system. In a preferred embodiment, the control system is configured to maintain the reactants in the vessel at or above temperature A and the substrate at temperature B below temperature A, transport the first reactant vapor from the vessel to the substrate, and deposit an organic film on the substrate.

[0019] In some embodiments, the apparatus is configured to deposit a polymer. In some embodiments, the polymer comprises a polyimide. In some embodiments, the apparatus is configured to deposit a polyamic acid. In some embodiments, the polyamic acid can be converted to a polyimide.

[0020] In some embodiments, the apparatus further comprises a gas line fluidly connecting the vessel to the reaction space, and the control system is further configured to maintain the gas line at a temperature C that is greater than temperature A.

[0021] In some embodiments, the control system is further configured to deliver vapor of the second reactant to the substrate alternately with vapor of the first reactant in a sequential deposition process.

[0022] In some embodiments, the apparatus further comprises an outlet line and an inert gas source connected to the reaction space, and the control system is further configured to remove excess reactant vapor and by-products between the delivery of the first reactant vapor and the second reactant vapor.

[0023] In another aspect, a method for reducing the aspect ratio of three-dimensional structures on a substrate is provided. The method includes vaporizing a first reactant to form a first reactant vapor. The substrate is exposed to the first reactant vapor in a reaction space, the substrate including a topography having three-dimensional structures. An organic film is preferentially deposited on the substrate over lower features of the topography relative to higher features of the topography, thereby reducing the aspect ratio of the three-dimensional structures on the substrate as it deposits. The depositing includes exposing the substrate to the first reactant vapor.

[0024] In another aspect, a method for forming an organic film is provided, the method including vaporizing a first reactant in a vaporizer to form a first reactant vapor, exposing a substrate in a reaction space to the first reactant vapor and a second reactant vapor, and forming a polyamic acid film from the first reactant vapor and the second reactant vapor on the substrate. [Brief explanation of the drawings]

[0025] [Figure 1A] FIG. 1 is a flow diagram illustrating a method for vapor phase deposition of organic films. [Figure 1B] FIG. 1 is a flow diagram illustrating a method for vapor phase deposition of organic films. [Figure 2A] FIG. 1 is a schematic diagram of an example of a vapor deposition apparatus that can be used for the deposition processes described herein. [Figure 2B] FIG. 1 is a schematic diagram of an example of a vapor deposition apparatus that can be used for the deposition processes described herein. [Figure 2C] FIG. 1 is a schematic diagram of an example of a vapor deposition apparatus that can be used for the deposition processes described herein. [Figure 2D] FIG. 1 is a schematic diagram of an example of a vapor deposition apparatus that can be used for the deposition processes described herein. [Figure 3A] 1 is a graph illustrating temperatures at various stages of a method for vapor deposition of an organic film. [Figure 3B] 1 is a graph illustrating temperatures at various stages of a method for vapor deposition of an organic film. [Figure 4A] 1 is an illustration of bottom-up filling of a trench by a method for vapor deposition of an organic film. [Figure 4B] 1 is an illustration of bottom-up filling of a trench by a method for vapor deposition of an organic film. [Figure 4C] 1 is an illustration of bottom-up filling of a trench by a method for vapor deposition of an organic film. [Figure 4D] 1 is an illustration of bottom-up filling of a trench by a method for vapor deposition of an organic film. [Figure 4E] 1 is an illustration of bottom-up filling of a trench by a method for vapor deposition of an organic film. [Figure 5A] 10A and 10B are thickness maps of films deposited by a deposition process using a deposition temperature higher than the vaporization vessel and a deposition process using a vaporization temperature higher than the deposition temperature, respectively. [Figure 5B] 10A and 10B are thickness maps of films deposited by a deposition process using a deposition temperature higher than the vaporization vessel and a deposition process using a vaporization temperature higher than the deposition temperature, respectively. [Figure 5C]10A and 10B are thickness maps of films deposited by a deposition process using a deposition temperature higher than the vaporization vessel and a deposition process using a vaporization temperature higher than the deposition temperature, respectively. [Figure 5D] 10A and 10B are thickness maps of films deposited by a deposition process using a deposition temperature higher than the vaporization vessel and a deposition process using a vaporization temperature higher than the deposition temperature, respectively. [Figure 6A] 1 is an illustration of bottom-up filling of a trench by a method for vapor deposition of an organic film. [Figure 6B] 1 is an illustration of bottom-up filling of a trench by a method for vapor deposition of an organic film. [Figure 7] 1 is a schematic side view of a vapor deposition apparatus according to certain embodiments described herein. [Figure 8] 1 is a schematic side view of a vapor deposition apparatus having a heated vapor distribution block according to certain embodiments. [Figure 9] FIG. 1 is a schematic top view of a vapor deposition apparatus having two heated vapor sources and two vapor feeds to a heated vapor distribution block in accordance with certain embodiments. [Figure 10] FIG. 10 is a schematic top view of an example gas distribution block for use with the embodiment of FIG. 8 or 9, having separate distribution of separate reactants. [Figure 11] 11 is a schematic side view of a vapor deposition apparatus incorporating the gas distribution block of FIG. 10. [Figure 12] 1 is a schematic side view of a vapor deposition apparatus having a common distribution channel for separate reactants. DETAILED DESCRIPTION OF THE INVENTION

[0026] Vapor deposition techniques can be applied to organic films and polymers, such as polyimide films, polyamide films, polyurea films, polyurethane films, and polythiophene films. CVD of polymer films can produce greater thickness control, mechanical flexibility, conformal coverage, and biocompatibility compared to the application of liquid precursors. Sequential deposition processing of polymers can produce high growth rates in small, research-scale reactors. Like CVD, sequential deposition processes can produce greater thickness control, mechanical flexibility, and conformality. The terms "sequential deposition" and "cyclic deposition" are used herein to apply to processes in which a substrate is exposed to different precursors alternately or sequentially, regardless of whether the reaction mechanism resembles ALD, CVD, MLD, or a hybrid thereof.

[0027] However, vapor deposition of organic films can be difficult for a variety of reasons. For example, reactants for making organic films tend to have low vapor pressures and volatilities, thus requiring high source temperatures for vaporization. It can be difficult to ensure that sufficient vapor pressure is generated to allow vapor deposition to proceed properly while avoiding thermal decomposition. Furthermore, while the substrate temperature is typically higher than the vaporizer temperature to drive the deposition reaction, high vaporization temperatures that increase the precursor vapor pressure can not only risk premature thermal decomposition but also result in excessively high deposition rates and consequent non-conformal deposition.

[0028] For example, polyimide films can be deposited by reacting a dianhydride with a diamine; the dianhydride typically used for this process is pyromellitic dianhydride (PMDA). At room temperature and atmospheric pressure, PMDA is a solid with a very low vapor pressure and therefore requires heating to evaporate. Miscontrol of the evaporation temperature during CVD / VDP of polyimide films can lead to crack formation, and despite its potential on a small research scale, the sequential deposition of polyimides on a manufacturing scale faces numerous challenges to manufacturability (e.g., particles, poor repeatability, clogged gas lines, poor uniformity, and low growth rate).

[0029] Due to stringent requirements for reactant volatility and growth temperature, it is difficult to obtain high-quality organic films using conventional vapor deposition techniques. Therefore, improved methods for the vapor deposition of organic thin films are needed.

[0030] In the embodiments described herein, the growth temperature at the substrate can be lower than the reactant source temperature. This temperature profile allows for a high enough vapor pressure for the reactants (e.g., precursors for organic film deposition, such as PMDA) to evaporate, and a low enough growth temperature to avoid overheating problems, enabling a high growth rate process. The deposition process taught herein can achieve high growth rates and throughput, producing high-quality organic thin films.

[0031] FIG. 1A is a simplified flow diagram of a method for vapor deposition of an organic film. In the first illustrated block 10, a first organic reactant is vaporized at temperature A to form a first reactant vapor. The vaporized reactant may be a liquid or solid at standard temperature and pressure conditions (room temperature and atmospheric pressure). In some embodiments, the vaporized reactant includes an organic precursor, such as a dianhydride, e.g., pyromellitic dianhydride (PMDA). In block 20, a substrate is exposed to the first reactant vapor at temperature B, which is lower than temperature A, and an organic film is deposited in block 30. This method can include additional steps and can be repeated, but not necessarily in the illustrated order or in the same order in each repetition, and can be easily extended to more complex vapor deposition techniques.

[0032] In some embodiments, the organic film comprises a polymer. In some embodiments, the deposited polymer is a polyimide. In some embodiments, the deposited polymer is a polyamide. In some embodiments, the deposited polymer is a polyurea. Other examples of deposited polymers include dimers, trimers, polyurethanes, polythioureas, polyesters, polyimines, other polymer forms, or mixtures of the above materials.

[0033] In some embodiments, the organic film comprises a precursor material to a polymeric film that can be converted or polymerized by a treatment process. For example, the as-deposited organic film comprises polyamic acid. In some embodiments, the polyamic acid is converted to a polyimide. In particular, polyamic acid is a common polyimide precursor that can be cyclized, i.e., imidized, to form polyimide. For vapor-phase deposition using dianhydrides and diamines, the composition of the as-deposited film has been found to depend on the substrate temperature. For example, in experiments, it was found that below about 130°C, the as-deposited film was predominantly polyamic acid. Between about 130°C and 160°C, the film was a mixture of polyamic acid and polyimide. Above about 160°C, the film was predominantly polyimide (polymer). Polyamic acid can be converted to polyimide by a variety of techniques, including annealing, plasma (e.g., with inert or noble gases), chemical treatment (e.g., with anhydrides), UV treatment, and other post-deposition treatments.

[0034] The term "about" is used herein to mean within standard measurement accuracy.

[0035] The techniques taught herein can be applied to vapor phase deposition techniques, including CVD, VPD, ALD, and MLD, in a wide variety of reactor configurations. Figure 1B is a simplified flow diagram of a sequential deposition process, and Figures 2A-2D illustrate schematic diagrams of example reactor configurations.

[0036] The flowchart in FIG. 1B illustrates a sequential deposition method for vapor-phase deposition of organic films. In block 10, a first organic reactant is vaporized at temperature A to form a first reactant vapor. In block 40, the first reactant vapor is transported through a gas line to a substrate at temperature C, which is higher than temperature A. In embodiments, the first reactant or a species thereof chemically adsorbs to the substrate in a self-saturating or self-limiting manner. The gas line may be any conduit that transports the first reactant vapor from a source to the substrate. In block 20, the substrate is exposed to the first reactant vapor at temperature B, which is lower than temperature A. In block 45, excess first reactant vapor (and any volatile reaction byproducts) is removed from contact with the substrate. Such removal can be achieved, for example, by purging, evacuation, moving the substrate away from the chamber or area where the substrate is exposed to the first reactant, or a combination thereof. In block 50, the substrate is exposed to a second reactant vapor. In embodiments, the second reactant may react with adsorbed species of the first reactant on the substrate. In block 60, excess second reactant vapor (and any volatile reaction by-products) is removed from contact with the substrate so that the first reactant vapor and the second reactant vapor do not mix. In some embodiments, the organic film vapor deposition process does not use plasma and / or radicals and can be considered a thermal vapor deposition process.

[0037] A variety of reactants can be used for these processes. For example, in some embodiments, the first reactant is an organic reactant, such as an acid anhydride, e.g., a dianhydride, e.g., pyromellitic dianhydride (PMDA), or any other monomer having two reactive groups. In some embodiments, the first reactant can be an acid anhydride, such as furan-2,5-dione (maleic anhydride). In some embodiments, the second reactant is also an organic reactant that can react with the adsorbed species of the first reactant under deposition conditions. For example, the second reactant can be a diamine, e.g., 1,6-diaminohexane (DAH), or any other monomer having two reactive groups that react with the first reactant. In some embodiments, a variety of reactants can be used to tailor film properties. For example, polyimide films and / or polyimide precursor material (e.g., polyamic acid) films could be deposited using 4,4'-oxydianiline or 1,4-diaminobenzene instead of 1,6-diaminohexane to obtain more aromaticity and a more rigid structure with increased dry etch resistance. In some embodiments, the reactants do not contain metal atoms. In some embodiments, the reactants do not contain metalloid atoms. In some embodiments, one of the reactants contains a metal or metalloid atom. In some embodiments, the reactants contain carbon and hydrogen and at least one of the following elements: N, O, S, P, or a halide such as Cl or F. Deposition conditions may vary depending on the reactants selected and can be optimized by selection. For sequential deposition of polyimide using PMDA and DAH in a single wafer deposition tool, the substrate temperature can be selected from a range of about 100°C to about 250°C, and the pressure can be selected from a range of about 1 mTorr to about 760 Torr, more specifically, between about 100 mTorr and about 100 Torr. In some embodiments, the vaporized reactant includes an organic precursor selected from the group consisting of 1,4-diisocyanatobutane or 1,4-diisocyanatobenzene.In some embodiments, the vaporized reactant comprises an organic precursor selected from the group consisting of alkyldioyl dichlorides, such as terephthaloyl dichloride, hexanedioyl dichloride, octanedioyl dichloride, nonanedioyl dichloride, and decanedioyl dichloride, or terephthaloyl dichloride. In some embodiments, the vaporized reactant comprises an organic precursor selected from the group consisting of 1,4-diisothiocyanatobenzene or terephthalaldehyde. In some embodiments, the vaporized reactant may be a diamine, such as 1,4-diaminobenzene, decane-1,10-diamine, 4-nitrobenzene-1,3-diamine, or 4,4'-oxydianiline. In some embodiments, the vaporized reactant may be terephthalic acid bis(2-hydroxyethyl) ester. In some embodiments, the vaporized reactant may be a carboxylic acid, such as an alkyl-, alkenyl-, or alkadienyl dicarboxylic or tricarboxylic acid, such as ethanedioic acid, propanedioic acid, butanedioic acid, pentanedioic acid, or propane-1,2,3-tricarboxylic acid. In some embodiments, the vaporized reactant may be an aromatic carboxylic or dicarboxylic acid, such as benzoic acid, benzene-1,2-dicarboxylic acid, benzene-1,4-dicarboxylic acid, or benzene-1,3-dicarboxylic acid. In some embodiments, the vaporized reactant may be selected from the group consisting of diols, triols, and aminophenols, such as 4-aminophenol, benzene-1,4-diol, or benzene-1,3,5-triol. In some embodiments, the vaporized reactant may be 8-quinolinol. In some embodiments, the vaporized reactant may include an alkenylchlorosilane, such as an alkenyltrichlorosilane, such as 7-octenyltrichlorosilane.

[0038] In block 30, an organic film is deposited. Those skilled in the art will appreciate that block 30 is not a separate operation but represents the result of blocks 10, 40, 20, 45, 50, and 60. Blocks 10-60 together define cycle 70, which can be repeated until a film of sufficient thickness remains on the substrate (block 80) and deposition is terminated (block 90). Cycle 70 can include additional steps, which need not be performed in the same order or identically in each repetition, and can be easily extended to more complex vapor deposition techniques. For example, cycle 70 can include additional reactant supply blocks, e.g., supplying and removing additional reactants in each cycle or selected cycles. Although not shown, the process can further include treating the deposited film (e.g., UV treatment, annealing, etc.) to form a polymer.

[0039] In some embodiments, the organic film does not contain metal atoms. In some embodiments, the organic film does not contain metalloid atoms. In some embodiments, the organic film contains metal or metalloid atoms. In some embodiments, the organic film contains carbon and hydrogen and at least one or more of the following elements: N, O, S, or P.

[0040] 2A is a simplified schematic diagram of an apparatus 100 for vapor-phase deposition of organic films. The apparatus includes a first reactant vessel 105 configured to vaporize a first organic reactant 110 into a first reactant vapor. A reaction chamber defines a reaction space 115 configured to accommodate at least one substrate 120. A control system 125 is configured to maintain the first reactant 110 in the first reactant vessel 105 at a temperature A and the substrate 120 in the reaction space 115 at a temperature B, where temperature B is lower than temperature A.

[0041] A gas line 130 fluidly connects the first reactant vessel 105 to the reaction space 115 and is configured to selectively transport vapor of the first reactant from the first reactant vessel 105 to an inlet manifold 135 and into the reaction space 115. In an embodiment, the control system 125 or a separate temperature control is configured to maintain the gas line 130 at a temperature C, where temperature C is greater than temperature A.

[0042] The apparatus 100 includes a second reactant vessel 140 that holds a second reactant 145. In some embodiments, the second reactant 145 is originally in a gaseous state, while in other embodiments, the second reactant vessel 140 is also configured to vaporize the second reactant 145 from an originally liquid or solid state. The second reactant vessel is in selective fluid communication with an inlet manifold 135. The inlet manifold can include a shared distribution plenum spanning the chamber width or can maintain separate passages to the reaction space 120 for the different reactants. For sequential deposition embodiments, it may be desirable to keep the reactant inlet passages separate until introduction into the reaction space 115 to avoid reactions along the surface of a common flow path for multiple reactants, which could lead to particle generation. The apparatus may include additional vessels for the supply of additional reactants in some embodiments.

[0043] One or more inert gas sources 150 are in selective fluid communication with the first reactant vessel 105 and the reaction space 115. The inert gas source 150 can also be in selective fluid communication with the illustrated second reactant vessel 140 and any other desired reactant vessels that function as carrier gases. A control system 125 is in communication with the valves of the gas distribution system according to the deposition methods described herein. In sequential deposition processes, the valves are operated to expose the substrate to alternating reactants, while in the case of simultaneous delivery of reactants in conventional CVD processes, the valves can be operated to simultaneously expose the substrate to reactants that react with each other.

[0044] An exhaust outlet 155 from the reaction space 115 communicates with a vacuum pump 165 through an exhaust line 160. A control system 125 is configured to operate the vacuum pump 165 to maintain a desired operating pressure and to exhaust excess reactant vapors and by-products through the exhaust outlet 155.

[0045] FIG. 2B schematically illustrates an example showerhead reaction chamber 200 that can be used for vapor deposition of organic films described herein. The reactor includes a showerhead 204 configured to receive and distribute reactant vapors across a substrate 206 on a substrate support 208. While illustrated as a single substrate chamber, those skilled in the art will appreciate that the shower reactor can accommodate multiple substrates. A reaction space 209 is defined between the showerhead 204 and the substrate 206. A first inlet 210 communicates with a source of a first reactant, and a second inlet 212 communicates with a source of a second reactant. Additional inlets (not shown) can be provided for separate sources of inert gas and / or additional reactants, and the showerhead 204 can also be provided with separate exhaust ports (not shown) to speed removal of reactants between stages in the case of sequential deposition (e.g., ALD) processes. Although both the first inlet 210 and the second inlet 212 are shown in communication with a single plenum of the showerhead 204, it should be understood that in other arrangements the inlets may independently supply reactants to the reaction volume and need not share a showerhead plenum. An exhaust outlet 214, shown in the form of an exhaust ring surrounding the base of the substrate support 208, is in communication with a vacuum pump 216.

[0046] FIG. 2C illustrates another configuration 230 of a reaction chamber that can be used for the vapor deposition of organic films described herein; features similar in function to those in FIG. 2B are referred to by like reference numerals. The reaction chamber 230, typically known as a horizontal flow reactor, is configured with a first reactant inlet 210 and a second reactant inlet 212 and an exhaust outlet 216. While illustrated as a single-substrate chamber, those skilled in the art will appreciate that this horizontal flow reactor can also accommodate multiple substrates. Additional inlets (not shown) can be provided for separate sources of inert gas and / or additional reactants. While separate inlets 210, 212 are shown to minimize deposition reactions upstream of the reaction space 209, as is generally preferred for sequential deposition reactors, it will be appreciated that in other configurations, different reactants can be supplied through a common inlet manifold, particularly for CVD process applications. The second inlet 212 is illustrated as supplying from a remote plasma unit 202; however, it will be appreciated by those skilled in the art that the RPU can be omitted or left unpowered for thermal deposition processes. It will be appreciated by those skilled in the art that in other types of horizontal flow reactors, different outlets may be operated alternately on different sides to feed these different reactants from different sides of the chamber, such that a first reactant can flow in one direction and a second reactant can flow in another direction in separate pulses.

[0047] FIG. 2D illustrates another example of a reaction chamber 240 that can be used for vapor deposition of organic films. The illustrated chamber is configured for spatially resolved sequential deposition reactions rather than time resolved reactions. Spatially resolved reactions use different zones through which the substrate moves, here zones A, B, C, and D. Alternatively, the gas injection system can move relative to the substrate, which may be stationary or rotating. The zones are separated by barriers 242, which may be physical walls that minimize vapor interaction between zones A-D, inert gas curtains, exhaust vents, or combinations thereof. The substrate support 208 may be in the form of a rotating stage, as shown, or a conveyor belt (not shown) for linearly arranged zones. In one example, zone A could be plumbed and operated to be consistently supplied with a first reactant, e.g., a precursor that adsorbs to the substrate; zones B and D could be plumbed and operated to be supplied with an inert gas or purge gas; and zone C could be plumbed and operated to be supplied with a second reactant that reacts with adsorbed species of the first reactant. The substrate 206 (four shown) moves between zones, sequentially exposing it to a first reactant (Zone A), an inert gas (Zone B), a second reactant (Zone C), and an inert gas (Zone D), before the cycle repeats. In spatially resolved plasma sequential deposition, the residence time of the reactants can depend on both the velocity of the reactants through the zones and the velocity of movement of the substrate support 208. In some cases, the substrate is stationary or rotates, and a gas delivery system, e.g., a gas injector, rotates above the substrate. The rotational speed of the injector or substrate can also affect the gas residence time. In a variation of spatially resolved sequential deposition, a combination of spatially resolved sequential deposition and time resolved sequential deposition could supply different reactants to the same zone at different times while the substrate moves between zones. Each zone may supply a separate reactant, or additional zones may be added by providing a larger platform separated by a larger number of zones or by providing a longer conveyor through a larger number of zones.

[0048] Although not shown, it will be readily apparent to those skilled in the art that the principles and advantages taught herein are applicable to other types of vapor deposition reactors, including batch reactors, e.g., vertical furnaces, known in the art for CVD and sequential deposition (e.g., ALD, cyclic CVD, and hybrid) processing.

[0049] The graphs in Figures 3A-3B illustrate temperatures at different stages of a method for vapor-phase deposition of organic films. Figure 3A illustrates a temperature profile along a reactant path according to an embodiment. A reactant source is vaporized at temperature A. The reaction chamber, or at least the substrate, is maintained at temperature B, which is lower than temperature A. Figure 3B illustrates a temperature profile in some embodiments in which reactant vapor is transported in a gas line from an evaporation vessel to the reaction chamber at temperature C, which is higher than temperature A. A higher temperature gas line reduces the risk of condensation and resulting contamination and / or gas line clogging.

[0050] The illustrated temperature profiles can be applied to a wide variety of vapor deposition processes involving low vapor pressure reactants and / or growth temperature constraints. The specific temperature for each reaction depends on several factors, including the reactants, desired film properties, deposition mechanism, and reactor configuration. These embodiments are particularly useful for evaporating organic precursors for vapor-phase organic film deposition.

[0051] Precursor condensation or multilayer adsorption can cause problems in repeatability and process stability. Condensation or multilayer adsorption can occur when the source temperature is higher than the deposition temperature. In some embodiments, the pressure in the source vessel and source line is higher than the pressure in the reaction chamber or zone where deposition occurs. This negative pressure differential can reduce the probability of precursor condensation and multilayer adsorption. This negative pressure differential can be applied to one or more of the reactants in a vapor deposition process, including both reactants subjected to the temperature profile illustrated in FIG. 3A and reactants not subjected to the temperature profile illustrated in FIG. 3A. In experiments, the PMDA source line was at 45-50 Torr, while the reaction chamber was at about 2-10 Torr. In some embodiments, the pressure differential between the source line and the reaction chamber or zone where deposition occurs can be greater than 1 mTorr, less than 760 Torr, between about 1 mTorr and 760 Torr, between about 5 mTorr and 300 Torr, between about 10 Torr and 200 Torr, and / or any of the other values ​​listed above. In some embodiments, the ratio of the pressure in the feed line to the pressure in the reaction chamber or zone where deposition occurs, expressed in Torr, may be greater than 1.01, less than 1000, between about 2 and 100, between about 3 and 50, between about 5 and 25, and any of the other values ​​recited above.

[0052] In some embodiments of the invention, temperature A may be above 120°C, below 250°C, between about 120°C and 200°C, between about 140°C and 190°C, and / or any other value between the above. In some embodiments, temperature B is between about 5°C and about 50°C lower than temperature A, between about 10°C and about 30°C lower than temperature A, and / or any other value between the above. In some embodiments, temperature C is between about 0.1°C and about 300°C higher than temperature A, between about 1°C and about 100°C higher than temperature A, between about 2°C and about 75°C higher than temperature A, between about 2°C and about 50°C higher than temperature A, and / or any other value between the above. In some embodiments, the ratio of temperature C to temperature A, expressed in Kelvin, is between about 1.001 and about 2.0, between about 1.001 and about 1.5, between about 1.001 and about 1.25, and / or between about 1.001 and about 1.10. In some embodiments, temperature C can be lower than temperature A but higher than temperature B. In some embodiments, temperature C can be between about 0.1° C. and about 200° C., between about 0.1° C. and about 50° C., or between about 0.1° C. and about 30° C. lower than temperature A, but higher than temperature B. However, in some embodiments, temperature C can be about the same as temperature A, but higher than temperature B. In some embodiments, temperatures A, B, and C can be about the same.

[0053] In addition to the low vapor pressure of the reactants, the particulate form of solid reactants can be problematic during vapor deposition. For example, if the pressure differential during pulsing for deposition is too large, particles can easily be blown or carried to the substrate. Filters are sometimes used to reduce particles being blown or carried to the substrate, but the filters can become clogged, significantly reducing gas line conductance and resulting in too low a coating rate. Therefore, it is preferable to limit the pressure differential during deposition to less than about 80 Torr, more specifically, less than about 50 Torr, thereby avoiding the use of filters.

[0054] It has been discovered that depositing organic films using the embodiments described herein facilitates tailoring of film morphology. In some embodiments, the use of alternating pulsing of reactants and equipment and lower deposition temperatures compared to precursor source vessels or vaporizers allows for the deposition of desirably non-conformal films on non-planar substrates, reducing the aspect ratio of the three-dimensional structures. In some embodiments, the non-planar substrate comprises trenches or vias or other three-dimensional structures. Films can be deposited to achieve thicker films over lower features of the substrate than over upper area regions of the substrate. Such bottom-up deposition is surprising given that conventional vapor deposition typically either grows faster over upper area regions (e.g., conventional CVD), leading to pinching and "keyhole" formation at the top of trenches, or is conformal (e.g., conventional sequential deposition processes).

[0055] 4A-4C are schematic diagrams of a vapor deposition process for reducing the aspect ratio of three-dimensional structures on a substrate according to some embodiments. FIG. 4A illustrates a schematic cross-sectional view of a substrate 400 having a pattern of 3D features in the form of trenches 410. In other embodiments, the substrate may have a different surface topography. The 3D features may be very small and have high aspect ratios, typically making it difficult for deposition to reach the bottom and fill the gaps of the features or trenches without forming voids. In the illustrated embodiment, the 3D features may have lateral dimensions of 5 nm to 10 μm, more specifically, about 5 nm to about 500 nm, or about 10 nm to about 200 nm. At the same time, the ratio of height to width, or aspect ratio, of the 3D feature, or in the illustrated embodiment, trench 410, can range from about 0.25 to 1000, about 0.5 to about 100, more specifically about 1.0 to 75, and even more specifically about 2.0 to about 50. FIG. 4B illustrates a cross-section of substrate 400 in which the deposited polymer 420 exhibits a reduction in the aspect ratio of trench 410 because deposition is favored at the bottom of the 3D feature in a bottom-up fill process as opposed to most vapor deposition techniques. FIG. 4C illustrates a cross-section of substrate 400 in which the deposited organic film 420 uniformly fills trench 410, with no visible seams or voids in a microscopic image. In some embodiments, the deposited organic film reduces the aspect ratio of the three-dimensional structure by about 1.5, about 5, and about 25 times or more, or in some embodiments, by about 100 times or more. In some embodiments, the deposited organic film reduces the aspect ratio of the substrate such that no substantial aspect ratio remains after deposition of the organic film, hi some embodiments, the deposited organic film fills a three-dimensional structure, such as a via or trench, at least about 50%, at least about 75%, at least about 90%, or at least about 95% of the volume of the three-dimensional structure, without any substantial seams or voids within the filled volume.In some embodiments, the deposited organic film completely fills a three-dimensional structure, such as a via or trench, and / or there is an organic film and a substantially planar film on the substrate above the upper level of the three-dimensional structure. The deposited organic film may include polyamic acid, polyimide, polyurea, polyurethane, polythiophene, and mixtures thereof.

[0056] Figures 4D-4E are electron micrographs showing the results of a negative temperature difference experiment in which PMDA and DAH were alternately and sequentially supplied to a substrate in a sequential deposition process to deposit a polyimide film. The first reactant, PMDA, was vaporized at a temperature of 150 °C, the PMDA gas line was maintained at 155 °C, and the substrate was maintained at 127 °C. A line flow rate of 450 sccm, a pump line pressure of 2 Torr, and a source line pressure of 40-100 Torr were used. Pulse / purge lengths of 11 / 8.1 seconds and 4.7 / 9 seconds were used for PMDA and DAH, respectively. Figure 4D illustrates a cross-section of a substrate 400 on which a polymer 420 was deposited by bottom-up filling of a trench 410 after 20 cycles. Figure 4E illustrates a cross-section of a substrate 400 on which a polymer 420 was deposited by bottom-up filling of a trench 410 after 60 cycles. The deposited film in FIG. 4E exhibits a relatively flat surface compared to the topography of the original trench.

[0057] In some embodiments, the film flatness can be adjusted based on the length of time that excess reactant vapor is removed from contact with the substrate. Reducing the time period during which excess reactant vapor is removed increases the flatness of the deposited organic film. In some embodiments, the removal of excess first reactant vapor and the removal of excess second reactant vapor are each performed for a period of greater than 1 second, less than 10 seconds, between about 1 second and about 10 seconds, and / or between any of the other values ​​recited above.

[0058] Example 1 Figures 5A-5D show the results of experiments comparing similar sequential deposition processes using a negative vaporizer-to-substrate temperature differential (Figures 5A and 5B) and a positive vaporizer-to-substrate temperature differential (Figures 5C and 5D). All experiments used 300 mm wafers in a PULSAR 3000™ beta ALD tool provided by ASM International, NV (Almere, The Netherlands). The negative temperature differential deposited films at more than three times the growth rate and produced films with much higher thickness uniformity compared to the process with a positive differential.

[0059] For negative temperature differential experiments, polyimide films were deposited by sequentially supplying alternating PMDA and DAH to the substrate in a sequential deposition process. The first reactant, PMDA, was vaporized at a temperature of 150 °C, the PMDA gas line was maintained at 153 °C, and the substrate was maintained at 127 °C. The second reactant, DAH, was maintained at 45 °C. A line flow rate of 450 sccm was used, with pulse / purge lengths of 11 / 8.066 seconds and 4.68 / 9 seconds for PMDA and DAH, respectively. The pulse operating pressure difference was set to approximately 45 Torr for PMDA, and no line filter was used. Sixty deposition cycles were applied, and the resulting films were analyzed by spectroscopic ellipsometry. Figures 5A and 5B show thickness maps obtained with a 200 mm and a 300 mm wafer mapping size, respectively, with a 3 mm edge exclusion in both cases. The growth rate was 5.1 Å per cycle, and the 1σ thickness non-uniformity was 0.6% and 1.4% using 200 mm and 300 mm mapping sizes, respectively.

[0060] For the positive temperature differential experiments, the first reactant, PMDA, was vaporized at a temperature of 140 °C, the PMDA gas line was maintained at 143 °C, and the substrate was maintained at 150 °C. The second reactant, DAH, was maintained at 45 °C. A line flow rate of 450 sccm was used, with pulse / purge lengths of 5 / 5 s and 2 / 5 s for PMDA and DAH, respectively. The pulse pressure difference was set to approximately 45 Torr for PMDA, and no line filter was used. 165 deposition cycles were applied, and the resulting films were analyzed by spectroscopic ellipsometry. Figures 5C and 5D show thickness maps obtained using either a 200 mm wafer mapping size or a 300 mm wafer mapping size, with a 3 mm edge exclusion applied in both cases. The growth rate was 1.6 Å per cycle, and the 1σ thickness nonuniformity was 1.1% and 6.0% using the 200 mm and 300 mm mapping sizes, respectively.

[0061] Example 2 In another negative temperature difference experiment performed on a trench-patterned wafer, PMDA and DAH were reacted in a sequential process to deposit polyimide films on the trench-patterned substrate. The trenches had variable pitches of 40 and 50 nm and openings of 25 to 35 nm. The first reactant, PMDA, was vaporized at a temperature of 150 °C. The PMDA gas line was maintained at 153 °C, and the substrate was maintained at 127 °C. The second reactant, DAH, was maintained at 45 °C. A line flow rate of 450 sccm was used, with pulse / purge lengths of 11 / 8.066 s and 4.68 / 9 s for PMDA and DAH, respectively. The resulting films were analyzed by tunneling electron microscopy (TEM). After 20 cycles, TEM images showed that the films thickened at the trench bottom area and thinned at the trench sidewalls. The film thickness on a flat wafer grown using the same parameters was 7 nm, with the film thickness on the bottom of some trenches being approximately 11 nm and the film thickness on the sides of some trenches being approximately 4 nm. Thus, growth proceeded faster in the bottom areas of the trenches, indicating bottom-up filling. After 60 deposition cycles, TEM analysis showed seamless bottom-up gap filling of the trenches with polyimide. The top surface was relatively smooth, demonstrating some self-planarizing behavior.

[0062] Example 3 In another negative temperature difference experiment, polyimide films were deposited on trench-patterned substrates by reacting PMDA and DAH in a sequential deposition process. Various purge lengths were used. One film used a purge length of 8.066 seconds for PMDA and 9.0 seconds for DAH. Another film used a purge length of 15 seconds for both PMDA and DAH. Another film used a purge length of 25 seconds for both PMDA and DAH. The resulting films were analyzed by TEM. Purge length did appear to affect gap-filling performance. However, shorter purges resulted in flatter films on the structures. Therefore, purge length can be used as a factor to adjust the final morphology of the film.

[0063] Example 4 In another negative difference experiment, PMDA and DAH were reacted in two separate alternating and sequential deposition processes at different temperatures. In the first experiment, PMDA was vaporized at 150°C and the substrate was maintained at 127°C. In the second experiment, PMDA was vaporized at 180°C and the substrate was maintained at 160°C. The film deposited in the first experiment was primarily polyamic acid, while the film deposited in the second experiment was primarily polyimide. The deposition temperature appears to affect the composition of the deposited film when the reactants are PMDA and DAH. Lower deposition temperatures appeared to result in a higher proportion of polyamic acid, while higher deposition temperatures appeared to result in a higher proportion of polyimide.

[0064] Example 5 In separate negative temperature difference experiments, the deposited polyamic acid films were annealed to form polyimides. The lower the deposition temperature, the greater the proportion of polyamic acid deposited when reacting PMDA with DAH. The conversion to polyimide was confirmed by FTIR spectroscopy. The data for four polyamic acid films annealed at different temperatures are as follows:

[0065] [Table 1]

[0066] Example 6 In separate negative temperature differential experiments, organic films were deposited at various temperatures. Thickness was analyzed using spectropotential spectroscopy (SE) and X-ray reflectivity (XRR) to measure thickness. Density and RMS roughness were also measured. Data for four films are as follows:

[0067] [Table 2]

[0068] Example 7 In another negative temperature difference experiment, deposited films were etched with water to confirm the conversion of polyamic acid to a more etch-resistant polymer, such as polyimide. Polyamic acid is water-soluble and can be etched by water. In contrast, polyimide is not water-soluble and cannot be etched by water. The first film was deposited at 127 °C and was therefore predominantly polyamic acid. The second film was deposited at 160 °C and was therefore predominantly polyimide. The third film was deposited at 127 °C and subsequently treated with argon plasma to convert the deposited polyamic acid to polyimide. The film thicknesses were measured before and after exposure to water and compared to quantify the extent of etching by water. The following data show that the polyamic acid film deposited at 127 °C was etched by water, while the polyimide film deposited at 160 °C and the polyamic acid film deposited at 127 °C and subsequently cured to form polyimide were not etched by water.

[0069] [Table 3]

[0070] [Table 4]

[0071] [Table 5]

[0072] Example 8 In another negative temperature difference experiment performed on a trench-patterned wafer, polyurea films were deposited on the trench-patterned substrate by reacting 1,4-phenylenediisocyanate (PDIC) with DAH in a sequential process. The trenches had variable pitches of 40 and 50 nm and openings of 25 to 35 nm. The first reactant, PDIC, was vaporized at a temperature of 75 °C. The PDIC gas line was maintained at 85 °C, and the substrate was maintained at 40 °C. The second reactant, DAH, was maintained at 45 °C. A line flow rate of 450 sccm was used, with pulse / purge lengths of 3 / 2 s and 8 / 7 s for PDIC and DAH, respectively. The resulting films were analyzed by tunneling electron microscopy (TEM). After 50 cycles, TEM images showed that the film thickened at the trench bottom area and thinned at the trench sidewalls (Figure 6A). The film thickness on a flat wafer grown using the same parameters was 7 nm, with the film thickness on the bottom of some trenches being approximately 10 nm and the film thickness on the sides of some trenches being approximately 3 nm. Thus, growth proceeded faster in the bottom areas of the trenches, indicating bottom-up filling. After 215 deposition cycles, TEM analysis (Figure 6B) showed seamless bottom-up gap filling of the trenches with polyurea. The aspect ratio of the three-dimensional features became smaller, indicating some self-planarization behavior.

[0073] 7-9 are high-level schematic diagrams of a vapor deposition apparatus configured to supply reactant vapor feedthroughs from the side of the reaction space, rather than relying on an overhead gas distribution system. The use of a side feedthrough shortens the path from the organic precursor vaporizer to the gas distribution block compared to a traditional overhead symmetrical feed, e.g., to a showerhead plenum. A shorter reactant path can be advantageous for operation and maintenance of the apparatus for vapor deposition of organic films, as described above. Other features of the vapor deposition apparatus, such as a second reactant source, reactant inlet, inlet manifold, exhaust outlet, and control system, are not shown for simplicity but can be as described, e.g., for FIG. 2A.

[0074] FIG. 7 is a schematic side view of a vapor deposition apparatus 700 according to certain embodiments described herein. The first reactant vessel 705 can be a heated reactant source, such as a vaporizer for an organic reactant suitable for ALD of organic films as described above. The inner reaction chamber defines a reaction space 115 capable of supporting one or more substrates. The gas lines 730 leading from the first reactant vessel 705 to the reaction space 715 are also heated. A separate outer vacuum chamber 732 surrounds the inner reaction chamber. The temperature profile can follow that of FIG. 3B, such that the gas lines 730 are at a higher temperature than either the temperature of the reactant vessel 705 or the substrate in the reaction space 715, and the reactant vessel 705 is at a higher temperature than the substrate temperature in the reaction space 715.

[0075] FIG. 8 shows a vapor deposition apparatus 700, in which like parts to those in FIG. 7 are referred to by like reference numerals. In FIG. 8, the inner reaction chamber is shown as comprising two parts: a heated block 735 and a reaction space 715. The heated block 735 can have a higher temperature than the heated gas lines 730, such that the temperature can rise from the reactant vessel 705 through the gas lines 730 to the heated block 735, and the substrate in the reaction space 715 is at a lower temperature than the reactant vessel 705. The heated block 735 can function to uniformly distribute reactant vapors across the substrate contained within the reaction space 715. For example, the heated block 735 can represent a showerhead above a substrate support (e.g., a susceptor) in the reaction space 715.

[0076] In Figures 7 and 8, both the heated reactant vessel 705 and the heated gas line 730 supplying the material into the reaction chamber are located on the side of the chamber. This arrangement facilitates reactor servicing, and the chamber can be easily opened from the top. In contrast, typical showerhead reactors supply reactants through the top of the chamber, symmetrically relative to the distribution perforations. Such overhead supply lengthens the path for reactants, especially for organic film deposition, and also makes opening the chamber for servicing more difficult. Heating the gas line 730, especially the portion feeding through the reaction chamber, is also easier when it is on the side, and the length of the feedthrough portion of the heated gas line 730 can be significantly reduced. Such an arrangement makes it more efficient and easier to eliminate cold spots from the line. Using shorter feedthrough lines also allows for better conductance, thus enabling larger precursor doses.

[0077] Although Figures 7 and 8 only show one heated reactant vessel and heated gas line for illustrative purposes, it will be apparent to one skilled in the art that the number of heated sources and heated lines can be two or more depending on the number and types of precursors in the organic film deposition recipe.

[0078] 9 is a schematic plan view of a vapor deposition apparatus 700 having two heated reactant vessels 705A and 705B and two heated gas lines 730A and 730B feeding a heated block 735 through an outer vacuum chamber 732, according to certain embodiments. The heated block 735 may be a gas distribution block (e.g., a showerhead) above a reaction space 715 that may include a substrate support. The substrate support may comprise a round susceptor plate attached to an elevator for easy wafer movement within the outer vacuum chamber 732.

[0079] The heated block 735 can uniformly distribute precursor gases from reactant source vessels 705A and 705B across the substrate(s) contained within the reaction space 715. The heated block 735 can have multiple designs. In one embodiment, all inlet gas feedthroughs are directed to the same space (e.g., a common showerhead plenum), and precursors flow from the same channel (e.g., showerhead perforations to the substrate within the reaction space 715). In another embodiment, different precursor gases are directed to the substrate through different channels, such that the reaction space 715 is the first place where the different reactants meet. Such an arrangement is preferred for certain ALD recipes to avoid reactions between mutually reactive elements occurring within the heated block 735, thus avoiding particle formation. In one example, a dual reactant showerhead can be used, providing separate plenums and separate perforations for the separate reactants. In another example, separate perforated pipes can be provided for the separate reactants. Whether the reactants should be kept separate or routed through a common distribution plenum depends on the actual reactants and the reaction temperatures for the deposition recipe.

[0080] FIG. 10 is a schematic plan view of an example gas distribution block 735 for separately distributing different reactants for use with the embodiment of FIG. 8 or 9. It is understood that the dimensions in the schematic are not to scale. In FIG. 10, heated gas lines 730A and 730B extend into perforated heated reactant distribution pipes 730A' and 730B' above a substrate 706 supported in the reaction space below the pipes. Distribution pipes 730A' and 730B' lead to exhaust port 716 using separately controllable valves 717A and 717B. Valves 717A and 717B can control precursor flow and purging from heated distribution pipes 730A' and 730B' between reactant stages.

[0081] FIG. 11 is a schematic side view of a vapor deposition apparatus incorporating the gas distribution block 735 of FIG. 10. Heated reactant vessels 705A and 705B feed heated gas lines 730A and 730B, which in turn extend into heated gas distribution pipes 730A' and 730B'. Valves 717A and 717B control flow from the gas distribution pipes 730A' and 730B' to an exhaust port 716 to control reactant flow and purge operation during operation. The distribution pipes 730A' and 730B' extend into a cover block 750 for the inner reaction chamber. The outer vacuum chamber 732 and the inner reaction chamber define a vacuum space 752 between them. A substrate 706 is shown supported on a substrate support 708, with an exhaust port 714 provided around the location where the substrate 706 is supported. The exhaust ports 716 for the gas distribution pipes 730A' and 730B' and the exhaust port 714 for the reaction space 715 can be connected to the same or different vacuum sources. A spacer 754 between the cover block 750 and the substrate support 708 helps seal the reaction space 715.

[0082] Figures 10 and 11 show one possible design for the components inside the heated gas distribution block 735. Two intertwined tubes 730A’ and 730B’ that zigzag across the substrate 706 are shown. The first reactant is dispersed across the substrate 706 from the holes in the first distribution tube 730A’, and the second reactant is distributed from the holes in the second distribution tube 730B’. Both tubes 730A’ and 730B’ lead to the pump exhaust section 716. When supplying the first reactant to the substrate, an inert carrier gas can be used to facilitate the flow of the reactant into the first distribution tube 730A’. The pressure in the reaction space 715 can be kept lower than that in the distribution tube 730A’, so that the precursor flows from the tube 730A’ to the surface of the substrate 706. In the ALD process, during purging between reactant pulses, the flow of the reactant is stopped and only the carrier gas flows through the first tube 730A’. Since the tube 730A’ also leads to the exhaust port 716, it can be purged efficiently. Valves 717A and 717B can be closed to facilitate the flow of the reactant into the reaction space 715 during reactant supply and opened again during purging. A gas distribution system such as this type of showerhead has the advantages of a showerhead but can purge more effectively to reduce particle formation. The size of the holes in the tubes can be optimized by experiments in a defined way. Tubes 730A’ and 730B’ extend into the cover block 750 to minimize the leakage of the reactant to the outer vacuum chamber 732, which leads to higher efficiency of precursor consumption.

[0083] As described above, the temperature gradient can increase from the reactant containers 705A and 705B to their respective gas lines 730A and 730B and continue to increase to the tubes 730A’ and 730B’ of the distribution block 735. The substrate support 708 and the substrate 706 supported thereon can be at a lower temperature than the reactant containers 705A and 705B and thus can also be at a lower temperature than the heated gas lines 730A and 730B and the gas distribution block 735. In other words, the system control can control the vaporization temperature A, the substrate temperature B, the gas line temperature C, and the gas distribution block temperature D such that B < A < C < D.

[0084] In deposition apparatus 700 of FIG. 11, reaction space 715 has its own exhaust port 714. In the illustrated embodiment, exhaust port 714 uniformly surrounds a substrate (e.g., a wafer), and gas is exhausted from all around the substrate.

[0085] FIGS. 10 and 11 show an example of a gas distribution block. In other embodiments, tubes 730A' and 730B' can be of different shapes, such as helical. Preferably, the flow paths have no sharp turns or corners so that gas flows smoothly and turbulence is minimized.

[0086] FIG. 12 is a schematic side view of a vapor deposition apparatus having a common distribution path for separate reactants, and components similar to those of FIG. 11 are referenced by the same reference numerals. The embodiment of FIG. 12 differs from FIG. 11 in that a conventional showerhead 760 functions as heated distribution block 735 instead of the tubes of FIG. 11. Temperature can rise from first reactant container 705A to corresponding heated gas line 730A, to corresponding feed-through line 730A', to showerhead 760. Similarly, temperature can rise from second reactant container 705B to corresponding heated gas line 730B, to corresponding feed-through line 730B', to showerhead 760. Substrate 706 in reaction space 715 below showerhead 760 can be at a lower temperature than reactant containers 705A and 705B and intervening features along the flow path. In other words, system control can control evaporation temperature A, substrate temperature B, gas line temperature C, gas feed-through temperature D, and gas distribution block temperature E for each reactant such that B < A < C < D < E. Similar to valves 717A, 717B of FIG. 11, valve 717C can control the purge of showerhead 760 between reactant flows and reactant pulses.

[0087] In other embodiments, the distribution block can be similar to the gas distribution systems of U.S. Patent Publication Nos. 2004216665, 20030075273, and 2004216668, the entire disclosures of which are incorporated herein by reference for all purposes. In such embodiments, as well as the embodiments of Figures 7-12, gases can be distributed overhead for more uniform distribution of reactants across the substrate compared to horizontal or cross-flow reaction chambers.

[0088] However, unlike conventional showerhead or dual showerhead gas distribution systems, the side feedthrough provides a shorter and less complicated flow path to the distribution block. Conventional showerhead systems generally do not perform well for low vapor pressure precursors, such as the organic precursors for the organic film deposition described herein. Conventional showerhead systems tend to have long precursor pipes connected to the top of the showerhead with numerous joints and valves, which can reduce efficient temperature control and cause particle generation due to cold spots. The illustrated side feedthrough, in addition to facilitating access for maintenance and cleaning during deposition runs, is more easily heated uniformly using appropriately positioned heaters and temperature sensors.

[0089] Furthermore, the deposition apparatus can be equipped with an in-situ cleaning system. Unlike inorganic films, organic films and precursor residues that may form along the gas distribution path of the deposition reactor described herein can be relatively easily cleaned by oxidation reactions. Therefore, in-situ cleaning can be achieved directly by supplying oxygen-containing vapor to the gas line or by separate supply to the gas distribution block 735. For example, O can be supplied to the gas distribution block 735 or to an upstream heated gas line or heated gas feedthrough. More preferably, for the in-situ cleaning cycle, an activated oxidizer, such as O gas or O plasma products, is periodically supplied during deposition or deposition operation.

[0090] While particular embodiments and examples have been discussed, it will be apparent to those skilled in the art that the scope of the claims extends beyond the specifically disclosed embodiments to other alternative embodiments and / or uses and obvious modifications and equivalents thereof.

Claims

1. 1. An apparatus for organic film deposition, comprising: a vessel configured to vaporize an organic reactant to form a reactant vapor; a reaction space configured to receive a substrate and to be in selective fluid communication with the vessel; maintaining the reactants in the vessel at or above a temperature A; maintaining the substrate at a temperature B which is lower than the temperature A; transporting the reactant vapor from the reservoir to the substrate; Depositing an organic film on the substrate a control system configured as follows: An apparatus comprising:

2. The device of claim 1 , wherein the organic film comprises a polymer.

3. The apparatus of claim 1 , wherein the container contains a solid at room temperature and atmospheric pressure.

4. The apparatus of claim 1 , wherein the container contains a dianhydride.

5. 10. The device of claim 1, wherein the container contains pyromellitic dianhydride (PMDA).

6. 10. The apparatus of claim 1, wherein the control system is further configured to maintain a ratio of temperature A to temperature B, in degrees Kelvin, between about 1 and about 1.

25.

7. 10. The apparatus of claim 1, wherein the control system is further configured to maintain the temperature B about 5°C to about 50°C lower than the temperature A.

8. 10. The apparatus of claim 1, further comprising a gas line fluidly connecting the vessel to the reaction space, the control system further configured to maintain the gas line at a temperature C, the temperature C being greater than the temperature A.

9. The apparatus of claim 1 , wherein the control system is further configured to deliver a vapor of a second reactant to the substrate in alternating sequences with the reactant vapor in a sequential deposition process.

10. 10. The apparatus of claim 1, further comprising an outlet line and an inert gas supply connected to the reaction space, wherein the control system is further configured to remove excess reactant vapor and by-products during delivery of the reactant vapor and second reactant vapor.

11. 1. A method for vapor deposition of an organic film, comprising: vaporizing a first organic reactant in a vaporizer at a temperature A to form a first reactant vapor; exposing a substrate to vapor of the first reactant in a reaction space at a temperature B lower than the temperature A; depositing the organic film on the substrate; A method comprising:

12. The method of claim 11 , wherein the organic film comprises a polymer.

13. The method of claim 12 , wherein depositing the organic film on the substrate comprises sequential vapor deposition.

14. The method of claim 13 , wherein depositing the organic film on the substrate comprises an atomic layer deposition process.

15. The method of claim 12 , wherein the polymer comprises a polyimide.

16. The method of claim 12 , wherein the polymer comprises a polyurea.

17. The method of claim 11 , wherein the organic film comprises a polyamic acid.

18. 20. The method of claim 17, further comprising converting the polyamic acid to a polyimide.

19. 12. The method of claim 11, wherein the first reactant is a solid at room temperature and atmospheric pressure.

20. 12. The method of claim 11, wherein the first reactant is an acid dianhydride.

21. 12. The method of claim 11, wherein the first reactant comprises pyromellitic dianhydride (PMDA).

22. 12. The method of claim 11, wherein the ratio of temperature A to temperature B in degrees Kelvin is between about 1 and about 1.

15.

23. 12. The method of claim 11, wherein said temperature B is between about 5°C and about 50°C lower than said temperature A.

24. 12. The method of claim 11 , wherein the substrate includes a non-planar topography, and depositing the organic film includes forming a first thickness over lower features of the substrate and depositing a second thickness over upper region areas of the substrate, the first thickness being greater than the second thickness.

25. The step of exposing the substrate includes self-limiting adsorption of a species of the first reactant onto the substrate, the method comprising: removing excess first reactant from contact with the substrate; exposing the substrate to the second reactant such that vapor of the first reactant and the second reactant do not substantially intermix; removing excess second reactant from contact with the substrate; The method of claim 11 further comprising:

26. 26. The method of claim 25, wherein the second reactant is a diamine.

27. 26. The method of claim 25, wherein each of the steps of removing excess first reactant vapor and removing excess second reactant vapor occurs for a period of about 1 second to about 10 seconds.

28. 26. The method of claim 25, further comprising repeating the steps of exposing the substrate to the vapor of the first reactant and exposing the substrate to the second reactant in a plurality of cycles such that the vapor of the first reactant and the second reactant do not substantially intermix.

29. 26. The method of claim 25, wherein the substrate includes a non-planar topography, and depositing the organic film includes forming a first thickness over lower features of the substrate and depositing a second thickness over upper region areas of the substrate, the first thickness being greater than the second thickness.

30. 12. The method of claim 11 , wherein exposing the substrate to vapor of the first reactant comprises transporting vapor of the first reactant through a gas line from the vaporizer to the reaction space, the gas line being at a temperature C, the temperature C being greater than the temperature A.

31. 12. The method of claim 11, further comprising removing excess first reactant vapor from contact with the substrate for a period of time, wherein decreasing the period of time increases planarity of the deposited organic film.

32. exposing the substrate to the second reactant such that vapor of the first reactant and the second reactant do not substantially intermix; removing excess second reactant from contact with the substrate; repeating the steps of exposing the substrate to the vapor of the first reactant and exposing the substrate to the second reactant in a plurality of cycles such that the vapor of the first reactant and the second reactant do not substantially intermix; 32. The method of claim 31 , further comprising:

33. 1. A method for reducing the aspect ratio of a three-dimensional structure on a substrate, comprising: vaporizing a first reactant to form a first reactant vapor; exposing a substrate to vapor of the first reactant in a reaction space, the substrate including a topography having a three-dimensional structure; preferentially depositing an organic film on the substrate over lower features of the topography compared to upper features of the topography such that as the organic film is deposited, the organic film reduces an aspect ratio of the three-dimensional structures on the substrate, the depositing comprising exposing the substrate to vapor of the first reactant; A method comprising:

34. 34. The method of claim 33, wherein the vaporization occurs at temperature A, the substrate is at temperature B during deposition, and the ratio of temperature A to temperature B, expressed in Kelvin, is between about 1 and about 1.

15.

35. 35. The method of claim 34, wherein temperature B is between about 5°C and about 50°C lower than temperature A.

36. The depositing step includes: exposing the substrate to a vapor of a second reactant to react with species of the vapor of the first reactant on the substrate; alternating sequentially exposing the substrate to vapor of the first reactant and exposing the substrate to vapor of the second reactant; 34. The method of claim 33, further comprising:

37. 34. The method of claim 33, further comprising controlling the vaporization temperature A and the substrate temperature B such that B<A.

38. 38. The method of claim 37, further comprising the step of in-situ cleaning the gas lines and / or reaction space with an oxygen-containing reactant.

39. 38. The method of claim 37, wherein the step of depositing an organic film comprises depositing a polyamic acid film, and further comprising converting the polyamic acid film to a polyimide film.

40. 38. The method of claim 37, wherein depositing the organic film comprises depositing a polymer film.

41. 34. The method of claim 33, wherein the first reactant is an organic reactant, and the exposing step comprises supplying vapor of the first reactant through heated gas lines extending through a side of a reactor defining the reaction space to a gas distribution block above the substrate within the reaction space.

42. 42. The method of claim 41, further comprising controlling the vaporization temperature A, the substrate temperature B, the gas line temperature C, and the gas distribution block temperature D such that B<A<C<D.

43. 43. The method of claim 42, wherein the gas distribution block maintains separate flow paths for the first reactant vapor and the second reactant vapor to reach the reaction space.

44. 43. The method of claim 42, wherein the gas distribution block comprises a common plenum through which the first reactant vapor and the second reactant vapor are supplied.

45. 42. The method of claim 41, wherein the gas distribution block comprises an outlet to an exhaust port and a valve for controlling exhaust from the gas distribution block for purging.

46. vaporizing a first reactant in a vaporizer to form a first reactant vapor; exposing a substrate to vapor of the first reactant and vapor of a second reactant in a reaction space; depositing a polyamic acid film from the first reactant vapor and the second reactant vapor onto the substrate; A method for forming an organic film, comprising:

47. 47. The method of claim 46, further comprising converting the polyamic acid film to a polyimide.

48. 47. The method of claim 46, wherein exposing the substrate to vapors of the first reactant and the second reactant comprises maintaining the substrate at a temperature between about 100° C. and about 150° C.

49. 47. The method of claim 46, wherein the first reactant comprises an acid dianhydride.

50. 50. The method of claim 49, wherein the dianhydride comprises pyromellitic dianhydride (PMDA).

51. 47. The method of claim 46, wherein exposing the substrate to the vapor of the first reactant and the vapor of the second reactant comprises alternately and sequentially exposing the substrate to the vapor of the first reactant and the vapor of the second reactant.

52. 52. The method of claim 51 , wherein the second reactant comprises a diamine.

53. 53. The method of claim 52, wherein the diamine comprises 1,6-diaminohexane (DAH).

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