Method for area-selective deposition of a polymer film using sequential pulse-initiated chemical vapor deposition (spiCVD)

Abstract

The present disclosure provides embodiments of an improved area-selective deposition (ASD) process and method for selectively depositing a polymer film on a variety of different target materials. More specifically, the present disclosure uses a cyclic vapor deposition process that sequentially exposes the surface of a substrate to a polymer precursor and then an initiator to selectively deposit a thin polymer film on a target material exposed on the substrate surface, providing an improved ASD process and related methods. The process of sequentially exposing the substrate surface to the precursor and the initiator can be repeated over one or more cycles of the cyclic vapor deposition process until a thin polymer film of a predetermined thickness is selectively deposited on the target material. In one embodiment, sequential pulse-initiated chemical vapor deposition (spiCVD) is used to selectively deposit a thin polymer film on the target material.

Description

Technical Field

[0001] Cross - Reference to Related Patents and Applications This application claims priority and the benefit of the filing date of U.S. Non - Provisional Patent Application No. 17 / 866,897, filed on July 18, 2022, which is hereby incorporated by reference in its entirety.

[0002] This disclosure relates to the processing of substrates. In particular, the present disclosure provides improved processes and methods for forming polymer thin films used in integrated circuit (IC) processing.

Background Art

[0003] As the geometry in substrate processing continues to shrink, the technical challenges of forming structures on substrates are increasing. Lithography technology is particularly challenging for the shrinking of geometry. One of the conventional substrate lithography methods utilizes a photolithography process including a photoresist coating step, an exposure step, and a photoresist development step. The materials and processes used in these steps can all affect critical dimension targeting, line roughness, and uniformity on the substrate.

[0004] As the feature sizes of integrated circuit (IC) devices continue to shrink down to the angstrom level, conventional lithography reaches its resolution limit or becomes too costly for large - scale use. One strategy is to use chemically - induced self - aligned selective bottom - up patterning to mitigate the dependence on lithography. Central to this strategy is area - selective processing (ASP), which focuses on the idea of using the surface chemistry of the exposed material layer to drive the selective processing of such layers. Area - selective processing techniques can be used to selectively deposit materials onto, and / or remove materials from, desired regions of a patterned substrate, thereby avoiding the use of photolithography for patterning.

[0005] Area-selective deposition (ASD) is an example of a bottom-up area-selective process that provides uniform deposition of material only on desired areas of a patterned substrate. Unlike conventional deposition techniques designed to achieve uniform deposition over a wide area, ASD enables selective deposition of material onto target areas (or "growth surfaces") while avoiding deposition on non-target areas (or "non-growth surfaces"). Using ASD, a variety of materials can be selectively deposited onto a target material. For example, using ASD technology, dielectric-on-dielectric (DoD), dielectric-on-metal (DoM), metal-on-dielectric (MoD), and metal-on-metal (MoM) can be selectively deposited.

[0006] Area-selective deposition can often be achieved using a variety of deposition techniques such as chemical vapor deposition (CVD), atomic layer deposition (ALD), and molecular layer deposition (MLD) that utilize surface modification and vapor deposition to deposit material onto target areas. Surface modification typically aims to promote the adsorption of precursor molecules on the growth surface and / or suppress the adsorption of precursor molecules on non-growth surfaces. For example, currently available DoD techniques often use molecular inhibitors such as self-assembled monolayers (SAMs) to suppress the deposition of dielectric materials on non-growth surfaces such as metal or metal oxide surfaces.

[0007] A self-assembled monolayer (SAM) is an organic molecule that forms a regular surface monolayer coating on a material that changes the chemical and physical properties of the material surface. Some SAM-forming molecules (e.g., those with thiol or carboxylic acid head groups) selectively assemble on metals relative to dielectric materials. For this reason, SAMs are used in various DoD applications to suppress dielectric growth on metal surfaces. For example, SAMs are used to passivate metal (e.g., copper) lines when manufacturing fully self-aligned vias (FSAVs) in the back end of line (BEOL). The passivation provided by the SAM enables selective dielectric growth on the interlayer dielectric (ILD) pattern by suppressing dielectric growth on the passivated metal lines.

[0008] Figures 1A - 1B (Prior Art) illustrate a conventional DoD process that suppresses dielectric growth on a metal surface using a SAM. As shown in Figure 1A, substrate 100 includes metal features 105 (e.g., metal lines) formed within dielectric pattern 110. SAM 115 is formed on metal feature 105 in Figure 1A, and when the deposition process continues to be carried out to selectively deposit dielectric material 120 on dielectric pattern 110 in Figure 1B, it suppresses dielectric growth on the exposed surface of metal feature 105.

[0009] Unfortunately, self - assembled monolayers (e.g., SAM 115 shown in Figures 1A - 1B) have the drawback of low thermal, mechanical, and storage - life stability, resulting in low effectiveness in selective DoD applications. For example, SAM - forming molecules tend to rearrange, desorb, or even move to adjacent dielectric patterns during processing or long - term storage, sometimes even pulling in metal impurities together (see Figure 1B). These events impair the ability of the SAM to enable selective DoD effectively without concerns about reliability. In addition, defects in SAM 115 can result in incomplete blanket coverage of metal feature 105. This incomplete coverage allows dielectric material 120 to grow on metal feature 105, thereby causing further concerns about reliability. Finally, since the SAM is only a few nanometers thick and has a flexible nature, it is not ideal for inducing vertical growth of the dielectric pattern. This leads to rapid growth of dielectric material 210 on metal feature 105 as shown in Figure 1B, thus compromising the critical dimensions of the pattern.

[0010] Similar to SAMs, polymers can be used to suppress or promote growth on one surface relative to growth on another surface. Optionally, a polymer thin film (e.g., a polymer film having a thickness of less than 20 nm) can be used as a sacrificial layer to drive selectivity during IC fabrication. Similar to SAMs, selective deposition of a polymer thin film can enable bottom-up patterning using a polymer sacrificial layer on a target region. The polymer sacrificial layer provides flexibility with respect to chemical and physical properties and ease of removal.

[0011] A variety of deposition techniques such as spin-on coating, dip coating, CVD, ALD, and MLD are used to deposit polymer thin films in both selective and non-selective processes. Optionally, ASD techniques are used to selectively deposit polymer-on-dielectric (PoD) and polymer-on-metal (PoM) via various deposition processes such as CVD, ALD, and MLD through a passivation metal or metal oxide (using a SAM). However, the deposition processes currently used to deposit polymer thin films on dielectrics and metals provide limited control over selectivity and the thickness of the deposited polymer film. SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0012] Therefore, there is a need for improved ASD processes and methods for selectively depositing polymer thin films on various material surfaces. MEANS FOR SOLVING THE PROBLEMS

[0013] The present disclosure provides various embodiments of an improved area-selective deposition (ASD) process and method for selectively depositing a polymer film on a variety of different target materials. More specifically, the present disclosure uses a cyclic vapor deposition process that sequentially exposes the surface of a substrate to a precursor and then an initiator to selectively deposit a polymer thin film on a target material exposed on the substrate surface. The process of sequentially exposing the substrate surface to the precursor and the initiator can be repeated over one or more cycles of the cyclic vapor deposition process described herein until a desired amount (or predetermined thickness) of the polymer thin film is selectively deposited on the target material. In at least one preferred embodiment, the improved ASD process and method described herein can use sequentially pulsed initiated chemical vapor deposition (spiCVD) to selectively deposit a polymer thin film on a target material.

[0014] The present disclosure also provides various embodiments of an improved process and method for stabilizing a self-assembled monolayer (SAM). In the present disclosure, a cyclic vapor deposition process is used to selectively deposit a polymer thin film on a SAM structure formed on a target material. The polymer thin film selectively deposited on the SAM structure stabilizes the SAM structure by (a) repairing defects in the SAM structure and providing a blanket coverage over the target material surface, (b) preventing SAM-forming molecules from migrating to adjacent non-target surfaces, and (c) increasing the thickness and rigidity of the SAM structure. In at least one preferred embodiment, the improved process and method for stabilizing the SAM structure can use spiCVD to selectively deposit a polymer thin film on the SAM structure.

[0015] In the first embodiment, a method for area-selective deposition (ASD) of a polymer film is provided. The method may include providing a substrate having a target material and a non-target material exposed on the surface of the substrate. The method further includes exposing the surface of the substrate to a vapor-phase precursor, which chemically reacts with and binds to the surface of the target material while avoiding the formation of condensates on the non-target material, to selectively form a condensate layer on the surface of the target material. The method also includes subsequently exposing the surface of the substrate to a vapor-phase initiator after the condensate layer has been selectively formed on the surface of the target material, and the vapor-phase initiator reacts with and polymerizes the condensate layer to selectively deposit a polymer film on the surface of the target material.

[0016] In an alternative of the first embodiment, the surface of the substrate is first exposed to the vapor-phase precursor for a precursor exposure time, and then the surface of the substrate is subsequently exposed to the vapor-phase initiator. The method may further include controlling the thickness of the polymer film by changing at least one of the precursor exposure time and the vapor pressure of the vapor-phase precursor. The method may further include repeating the exposing the surface of the substrate to the vapor-phase precursor and the subsequently exposing the surface of the substrate to the vapor-phase initiator for a predetermined number of cycles to selectively deposit a polymer film of a predetermined thickness on the surface of the target material without contaminating the non-target material with the polymer. The method may also include controlling the amount of the polymer film selectively deposited on the target material per cycle by changing at least one of the precursor exposure time and the vapor pressure of the vapor-phase precursor. In one alternative, before exposing the surface of the substrate to the vapor-phase precursor, the method includes determining a selectivity window based on the polymer growth rate achieved per cycle on the target material and the non-target material, and selecting from the selectivity window the predetermined number of cycles required to selectively deposit a polymer film of a predetermined thickness on the surface of the target material without contaminating the non-target material with the polymer.

[0017] In another alternative of the first embodiment, the target material is a dielectric material and the non-target material is a metal or metal oxide material. In another alternative, exposing the surface of the substrate to the vapor-phase precursor includes exposing the surface of the substrate to a monomer precursor, which chemically reacts with and binds to the surface of the dielectric material while avoiding the formation of condensates on the metal or metal oxide material, to selectively form a monomer condensation layer on the surface of the dielectric material. Subsequently exposing the surface of the substrate to the vapor-phase initiator polymerizes the monomer condensation layer to selectively deposit a polymer film on the surface of the dielectric material. In yet another alternative, exposing the surface of the substrate to the vapor-phase precursor includes exposing the surface of the substrate to a dielectric precursor, which chemically reacts with and binds to the surface of the dielectric material while avoiding the formation of condensates on the metal or metal oxide material, to selectively form a condensation layer on the surface of the dielectric material. Subsequently exposing the surface of the substrate to the vapor-phase initiator polymerizes the condensation layer to selectively deposit a dielectric film on the surface of the dielectric material.

[0018] In yet another alternative of the first embodiment, the target material is a metal or metal oxide material and the non-target material is a dielectric material. In another alternative, prior to exposing the surface of the substrate to the vapor-phase precursor, the method further includes forming a self-assembled monolayer (SAM) on the surface of the metal or metal oxide material to form a SAM-passivated metal or metal oxide. In yet another alternative, exposing the surface of the substrate to the vapor-phase precursor includes exposing the surface of the substrate to a monomer precursor, which selectively condenses on the SAM while avoiding the formation of condensates on the dielectric material, to form a monomer condensation layer on the SAM-passivated metal or metal oxide. Subsequently exposing the surface of the substrate to the vapor-phase initiator polymerizes the monomer condensation layer to selectively deposit a polymer film on the SAM-passivated metal or metal oxide.

[0019] In a second embodiment, a method for area-selective deposition (ASD) of a polymer film is provided. The method may include providing a substrate having a target material and a non-target material exposed on a surface of the substrate. The method further includes sequentially exposing the surface of the substrate to a vapor-phase precursor and a vapor-phase initiator such that the surface of the substrate is first exposed to the vapor-phase precursor for a precursor exposure time and then subsequently exposed to the vapor-phase initiator, wherein the vapor-phase precursor chemically reacts with and binds to the surface of the target material to selectively form a condensate layer on the surface of the target material while avoiding formation of a condensate on the non-target material, and the vapor-phase initiator reacts with and polymerizes the condensate layer to selectively deposit a polymer film on the surface of the target material. The method also includes repeating the sequential exposure of the surface of the substrate to the vapor-phase precursor and the vapor-phase initiator for a predetermined number of cycles to selectively deposit a polymer film of a predetermined thickness on the surface of the target material without contaminating the non-target material with the polymer.

[0020] In an alternative of the second embodiment, the method further includes controlling the amount of polymer film selectively deposited on the target material per cycle by changing at least one of the precursor exposure time and the vapor pressure of the vapor-phase precursor. In one alternative, the amount of polymer film selectively deposited on the target material per cycle is less than 2 nm. In another alternative, prior to exposing the surface of the substrate to the vapor-phase precursor, the method further includes determining a selectivity window based on the polymer growth rate achieved per cycle on the target material and on the non-target material, and selecting from within the selectivity window a predetermined number of cycles required to selectively deposit a polymer film of a predetermined thickness on the surface of the target material without contaminating the non-target material with the polymer.

[0021] In yet another alternative form, the target material is a dielectric material and the non-target material is a metal or metal oxide material. In another alternative form, sequentially exposing the surface of the substrate to the vapor phase precursor and the vapor phase initiator comprises first exposing the surface of the substrate to a monomer precursor, the monomer precursor chemically reacting with and bonding to the surface of the dielectric material while avoiding formation of condensates on the metal or metal oxide material to selectively form a monomer condensation layer on the surface of the dielectric material, and subsequently exposing the surface of the substrate to a vapor phase initiator to polymerize the monomer condensation layer and selectively deposit a polymer film on the surface of the dielectric material. In yet another alternative form, sequentially exposing the surface of the substrate to the vapor phase precursor and the vapor phase initiator comprises first exposing the surface of the substrate to a dielectric precursor, the dielectric precursor chemically reacting with and bonding to the surface of the dielectric material while avoiding formation of condensates on the metal or metal oxide material to selectively form a condensation layer on the surface of the dielectric material, and subsequently exposing the surface of the substrate to a vapor phase initiator to polymerize the condensation layer and selectively deposit a dielectric film on the surface of the dielectric material. In one alternative form, the dielectric material is a low-k dielectric, and in another alternative form, the dielectric material is a low-k dielectric deposited by spiCVD.

[0022] In another alternative of the second embodiment, the target material is a metal or metal oxide material, and the non-target material is a dielectric material. In another alternative, prior to sequentially exposing the surface of the substrate to the vapor-phase precursor and the vapor-phase initiator, the method further includes forming a self-assembled monolayer (SAM) assembly on the surface of the metal or metal oxide material to modify the chemical and / or physical surface properties of the metal or metal oxide material and form a SAM-passivated metal or metal oxide. In a variant of this alternative, sequentially exposing the surface of the substrate to the vapor-phase precursor and the vapor-phase initiator as described above first involves exposing the surface of the substrate to a monomer precursor, which selectively condenses on the SAM assembly while avoiding the formation of condensates on the dielectric material to form a monomer condensation layer on the SAM-passivated metal or metal oxide, and subsequently exposing the surface of the substrate to a vapor-phase initiator to polymerize the monomer condensation layer and selectively deposit a polymer film on the SAM-passivated metal or metal oxide.

[0023] The present invention and its advantages will be more fully understood by reference to the following description in conjunction with the accompanying drawings, in which like reference numerals refer to like features. However, it should be noted that the accompanying drawings illustrate only multiple exemplary embodiments of the disclosed concept, and the disclosed concept may also encompass multiple other equally valid embodiments, and thus do not limit the scope of the present invention.

Brief Description of the Drawings

[0024]

Figure 1A-1B

Figure 2

Figure 3

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Figure 5A-5C

Figure 6A-6D

Figure 7A-7B

Figure 8A-8E

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

[0025] The present disclosure provides various embodiments of an area selective deposition (ASD) process and method for selectively depositing a polymer film on a variety of different target materials. More specifically, the present disclosure uses a cyclic vapor deposition process in which the surface of a substrate is sequentially exposed to a precursor (e.g., a monomer or a dielectric precursor) and then an initiator to deposit a controlled amount of polymer on the target material exposed on the substrate surface, to selectively deposit a polymer thin film on the target material. The process of sequentially exposing the substrate surface to the precursor and the initiator can be repeated over one or more cycles of the cyclic vapor deposition process described herein until the desired amount (or predetermined thickness) of polymer is deposited on the target material.

[0026] SAM stabilization is one way to make the SAM a reliable strategy for ASD, more specifically DoD. In one approach, the SAM is not replaced with a polymer film, rather, the SAM is reinforced with a polymer film. In other approaches, only thin film polymers can be used for ASD (not necessarily DoD).

[0027] In at least one preferred embodiment, a sequential pulse initiation chemical vapor deposition (spiCVD) process can be used to selectively deposit a polymer thin film on a target material. SpiCVD is a vapor phase polymer deposition technique that enables the controlled deposition of polymer thin films at low temperatures. As described in more detail below, spiCVD is a periodic deposition process that relies on the sequential introduction of a precursor and an initiator onto the surface of a substrate. The surface of the substrate is first exposed to the precursor to form a thin condensation layer only on the target area of the substrate. Subsequently, when the initiator is introduced, the initiator activates the precursor, causing polymerization of the precursor condensation layer to form an ultrathin polymer film on the target area of the substrate. The ultrathin polymer film deposited in the first spiCVD cycle can be less than 2 nm and, in some embodiments, can be less than 1 nm. In some embodiments, the spiCVD process can be repeated over one or more cycles to form additional ultrathin polymer film layers until a polymer film of a predetermined thickness (e.g., less than 20 nm) is selectively deposited on the target area of the substrate.

[0028] Utilizing the spiCVD process to selectively deposit a polymer thin film on a target material provides a number of advantages over other deposition techniques. For example, the sequential nature of the spiCVD process described herein enables the controlled coating of ultrathin amounts (e.g., 1-2 nm or less) of polymer on a target material. In some embodiments, the amount of polymer selectively deposited on the target material per spiCVD cycle can be controlled by varying the precursor exposure time, precursor vapor pressure, temperature, and / or surface properties of the target material. In this way, spiCVD can be used to finely tune the amount of polymer deposited on a target material, sometimes providing control of the deposition process at the angstrom (Å) level. The periodic nature of the spiCVD process enables a more uniform deposition of the polymer film on the target material, while the precursor promotes the selectivity of deposition by enabling area-selective deposition in patterns of materials with different wetting properties.

[0029] By using spiCVD, the ASD processes described herein can be used to selectively deposit polymer thin films on a variety of target materials including dielectric materials, metal and metal oxide materials, and metals / metal oxides passivated with self-assembled monolayers (SAMs). The precursors selected for the deposition process serve as the driving force for selectivity. The chemical nature of the substrate surface also serves as a driving force for selectivity. As described in more detail below, by selecting precursors that have a high chemical affinity for the target material and a low chemical affinity for non-target materials present on the same substrate, a variety of precursors can be used to deposit polymer thin films on different target materials. This enables the precursors selected for the deposition process to selectively condense on the target material while avoiding the formation of condensates on non-target materials. The selective condensation of precursors, which can be driven by dewetting and / or chemical / physical forces at the surface of the target material, enables the area-selective placement of polymer thin films on metal / dielectric patterns.

[0030] In some embodiments, selectivity can also be affected by the polymer deposition thickness. In some deposition processes, for example, the polymer thin film can be selectively deposited on the target material up to a threshold deposition thickness, beyond which further deposition leads to a loss of selectivity. Due to the periodic nature of the spiCVD process described herein, selectivity can be maintained by determining the number of cycles required to effectively coat the target material while preventing polymer deposition on non-target materials. In some embodiments, the number of cycles can be determined based on the polymer growth rate achieved per spiCVD cycle on the target material and non-target materials.

[0031] To demonstrate the feasibility of selectively depositing polymer thin films on dielectric and metal surfaces using spiCVD, experiments were first conducted on planar blanket substrates of silicon dioxide (SiO2) and copper (Cu). In these experiments, polymer thin films were deposited on the planar blanket substrates by sequentially exposing the surface of the substrates to the precursor and then the initiator in the spiCVD process. In these experiments, glycidyl methacrylate (GMA) was used as the precursor, and tert-butyl peroxide (TBPO) was used as the initiator to initiate GMA polymerization to form polyglycidyl methacrylate (pGMA) on the planar blanket substrates. To measure the pGMA film thickness and surface roughness achieved for each deposition cycle, experiments were conducted for various precursor exposure times and numbers of spiCVD cycles. After optimizing the deposition of pGMA on the planar blanket substrates using spiCVD, additional experiments were carried out to optimize the process on patterned substrates such as substrates with SiO2 and Cu line patterns.

[0032] In one experiment, spiCVD was used to deposit pGMA on a planar blanket SiO2 substrate by first exposing the surface of the SiO2 substrate to the GMA precursor to form a condensation layer on the SiO2 substrate. During various precursor exposure times (e.g., 20 seconds, 60 seconds, 120 seconds, and 240 seconds), the GMA precursor was supplied to the substrate surface at a vapor pressure of about 1 torr and a temperature of 160 °C to 170 °C. When the SiO2 substrate was exposed to the vapor-phase GMA precursor, the GMA precursor selectively condensed on the surface with a high chemical affinity for precursor chemisorption to form a precursor condensation layer. Subsequently, introduction of TBPO to initiate GMA polymerization polymerized the precursor condensation layer to form an ultrathin pGMA film on the SiO2 substrate. By performing additional cycles of the spiCVD process, the thickness of the deposited pGMA film was increased. The experiments demonstrated that ultra-fine tuning of the pGMA film thickness can be achieved by carefully controlling the GMA vapor pressure and GMA exposure time.

[0033] From preliminary studies on polymer thin film deposition on a blanket substrate, it has been found that spiCVD can be used to provide uniform deposition of pGMA thin films in the range of, for example, 1 to 10 nm. Graph 200 shown in Figure 2 shows the pGMA film thickness (expressed in nanometers, nm) achieved using the above spiCVD process for various GMA precursor exposure times (e.g., 20 seconds, 60 seconds, 120 seconds, and 240 seconds). As shown in Graph 200, the pGMA film thickness increases with the increase in precursor exposure time and number of cycles.

[0034] Graph 300 shown in Figure 3 shows the surface roughness (Ra) of the deposited pGMA film (expressed in nm) achieved using the above spiCVD process for various GMA precursor exposure times (e.g., 20 seconds, 60 seconds, 120 seconds, and 240 seconds). As shown in Graph 300, first, the surface roughness increases (e.g., due to nuclei and single-chain polymers) during the first spiCVD cycle, and then the polymer films coalesce during the next spiCVD cycle, resulting in uniform deposition of an ultra-thin polymer film. The degree of uniformity can generally depend on the type of substrate or target material on which the polymer film is deposited.

[0035] When depositing a pGMA thin film on a SiO2 substrate, the above spiCVD process was observed to follow a two-mode deposition process. Graph 400 shown in FIG. 4 is a plot of the surface roughness (expressed in nm) of the deposited pGMA film measured by atomic force microscopy (AFM) at different pGMA film thicknesses. Graph 400 shown in FIG. 4 exhibits two growth modes. In the first mode, which is determined by the substrate surface, a uniform ultrathin polymer film of about 1-2 nm (otherwise referred to as a two-dimensional or “2D” polymer film) is deposited on the SiO2 substrate surface with excellent blanket coverage. The degree of uniformity and surface coverage in such ultrathin polymer films is remarkable considering their thickness. The second deposition mode occurs when additional spiCVD cycles are performed to achieve further polymer deposition on the 2D polymer film. At this stage, a bulk polymer film is formed and follows conventional iCVD growth behavior. At least a portion of the uniformity achieved with such 2D polymer films may be attributed to the sequential nature of the spiCVD process, which allows the precursor to be sufficiently distributed and “wetted” on the target surface before polymerization. Such 2D polymer films can have important implications for various surface coating applications such as surface passivation, anti-fouling applications, surface activation, functionalization, etc.

[0036] In addition to the blanket polymer film, the periodic and sequential nature of the spiCVD process enables area-selective deposition (ASD) of polymer films on a variety of target materials. In a pattern containing two different materials with different wettabilities for the precursor, using the spiCVD process described herein, one material surface can be selectively coated with a polymer thin film, and the polymer coating of the other material surface can be avoided. The polymer patterns deposited by spiCVD can have applications in a variety of areas, including area-selective deposition (ASD) of polymer-on-dielectric, polymer-on-metal ASD, polymer-on-SAM passivated surface ASD, and carbon hard mask or photoresist-based pattern correction. The polymer thin films deposited by spiCVD can also function as dummy structures for inducing growth or etching in various structures. Thus, the present disclosure contemplates a variety of applications in which the techniques described herein can be used to deposit polymer thin films in IC manufacturing.

[0037] Returning to the drawings, FIGS. 5-6 and 8 show various embodiments of an area-selective deposition (ASD) process that can be used to selectively deposit a polymer film on a variety of different target materials using a periodic vapor deposition process. More specifically, FIGS. 5-6 and 8 show an improved ASD process that utilizes spiCVD to selectively deposit a polymer thin film on a variety of target materials (e.g., dielectric materials, metal and metal oxide materials, and SAM passivated metal / metal oxides). However, it is recognized that the processes shown in FIGS. 5-6 and 8 are merely examples of the application of the techniques described herein.

[0038] Selective Polymer-on-Dielectric (PoD) Deposition Figures 5A - 5C illustrate an improved ASD process that can be used to selectively deposit a polymer thin film on a dielectric material in accordance with the present disclosure. More specifically, Figures 5A - 5C illustrate an improved polymer - on - dielectric (PoD) process that utilizes spiCVD to selectively deposit a polymer thin film on a dielectric material while avoiding polymer deposition on non - target materials such as metal or metal oxide materials provided on the same substrate.

[0039] In the embodiment shown in Figure 5A, a substrate 500 is provided with a metal / dielectric pattern having a metal layer 505 and a dielectric layer 510 exposed on the surface of the substrate 500. The metal layer 505 can include, but is not limited to, various metal and metal oxide materials such as copper (Cu), ruthenium (Ru), cobalt (Co), tungsten (W), molybdenum (Mo), and their oxides. The metal layer 505 can also include other metal and metal oxide materials commonly used in integrated circuit (IC) manufacturing as is known in the art. The dielectric layer 510 can include a variety of dielectric materials including oxides, silicon oxides (including silicon dioxide, SiO2), and other low - k and high - k dielectric materials commonly used in IC manufacturing, but is not limited thereto. Depending on the dielectric material used, the surface of the dielectric layer 510 can be terminated with - O, - H, or OH bonds.

[0040] In the embodiment shown in Figure 5B, the surface of the substrate 500 is exposed to a vapor - phase precursor (P) 515, which chemically reacts with and binds to the - OH bonds on the surface of the dielectric layer 510 to selectively form a thin condensation layer 520 on the dielectric surface. The - OH bonds have a high affinity for precursor chemisorption and provide active sites, while the metal (or metal oxide) atoms present on the surface of the metal layer 505 have a low affinity for precursor chemisorption. Thus, the condensation layer 520 is selectively formed on the dielectric surface relative to the metal surface.

[0041] The precursor 515 used in FIG. 5B may include any monomer precursor that can be deposited by (a) chemical vapor deposition and (b) initiated / activated by an initiator to achieve polymerization. In one embodiment, the precursor 515 used in FIG. 5B can be glycidyl methacrylate (GMA). Although GMA is provided as an example, the precursor 515 is not strictly limited to GMA and can include other monomer precursors such as alkyl acrylates, alkyl cyclosiloxanes, perfluoroalkyl ethyl methacrylate, and trivinyltrimethylcyclotrisiloxane, but is not limited thereto. In addition to precursor selection, the vapor pressure and exposure time of the precursor 515 can be carefully selected to provide a uniform ultrathin coating of the condensation layer 520 on the surface of the dielectric layer 510 before the initiator is introduced in FIG. 5C.

[0042] In the embodiment shown in FIG. 5C, the surface of the substrate 500 is subsequently exposed to the vapor-phase initiator (I) 525, and the vapor-phase initiator (I) 525 reacts with the condensation layer 520 and polymerizes it to form an ultrathin (e.g., 1 to 2 nm or less) polymer film 530 on the surface of the dielectric layer 510. The initiator 525 can include any chemical species that can be deposited by (a) chemical vapor deposition and (b) react with a monomer to form an intermediate compound that can continuously link with a number of other monomers to form a macromolecular compound. In one embodiment, tert-butyl peroxide (TBPO) can be used as the initiator 525. When TBPO is introduced in FIG. 5C, TBPO initiates the polymerization of GMA to form poly-glycidyl methacrylate (pGMA). Although TBPO is provided as an example, other initiators can also be used to activate the precursor 515 and cause the polymerization of the condensation layer 520 to form the polymer film 530. Examples of other initiators include, but are not limited to, perfluorooctanesulfonyl fluoride, triethylamine, and organic peroxides. Alternative initiation can be performed using photons (e.g., UV photons), an electron beam, or thermal means.

[0043] After the polymer film 530 is formed, the process of sequentially exposing the surface of the substrate 500 to the precursor 515 in FIG. 5B and to the initiator 525 in FIG. 5C can be repeated over one or more cycles of the spiCVD process described herein until a desired amount (or predetermined thickness) of the polymer film 530 is selectively grown or deposited on the surface of the dielectric layer 510. In some embodiments, the sequential process steps shown in FIGS. 5B and 5C can be repeated about 32 cycles to selectively deposit a polymer film 530 of up to 16 nm on the dielectric layer 510. In other examples, a range of 1 to 40 cycles (or more) can be utilized to provide a film of 0.5 to 20 nm depending on the precursor exposure time. In some embodiments, the number of cycles used to effectively coat the dielectric surface while avoiding contamination of the metal surface can be determined based on the polymer growth rate achieved per cycle of the spiCVD process and can be used to maintain selectivity.

[0044] Experiments were conducted to selectively deposit a pGMA film on a patterned substrate consisting of an interlayer dielectric (ILD) and copper (Cu) line patterns using the above-described spiCVD process shown in FIGS. 5A-5C. Using the above-described spiCVD process, a polymer pattern having a thickness in the range of 1-16 nm was formed on the ILD lines without significantly contaminating the copper surface. This selectivity is at least partially driven by a wetting / dewetting mechanism that allows a GMA monomer (or another monomer having a high affinity for the ILD surface compared to the Cu surface) to selectively coat or "wet" the ILD surface without contaminating the copper surface. After the ILD surface is coated with GMA condensate, residual GMA molecules can be further dewet from the adjacent copper surface because of the higher affinity of the GMA molecules for aggregating with the GMA condensate. This mechanism is very effective in inducing selective polymer growth with excellent pattern shape. Selective condensation on ILD vs. copper can be driven by a combination of chemical and physical interactions at the target and non-target surfaces and is expected to vary depending on the type of polymer precursor.

[0045] Selective Dielectric on Dielectric (DoD) Deposition In some embodiments, the selective PoD process shown in FIGS. 5A-5C can be used in the back end of line (BEOL) during IC manufacturing to form a dielectric on dielectric (DoD) pattern. In one exemplary BEOL application, the spiCVD process shown in FIGS. 5A-5C can be used to selectively deposit a low-k dielectric film on a dielectric pattern used to fabricate a fully self-aligned via (FSAV). However, instead of exposing the surface of substrate 500 to the monomer precursor, the substrate surface can be exposed to dielectric precursor 515 in FIG. 5B to form dielectric condensate layer 520.

[0046] The dielectric precursors used in the DoD process to deposit a low-k dielectric film on a dielectric pattern can be any dielectric precursor that can be deposited by chemical vapor deposition, such as spiCVD. In one embodiment, the dielectric precursor 515 can be a precursor of a low-k dielectric material, such as one based on polysiloxane. After sufficient exposure to the dielectric precursor 515, the surface of the substrate 500 can be exposed to an initiator 525, which reacts with and polymerizes the dielectric condensation layer 520 to form a low-k dielectric film 530 on the surface of the dielectric layer 510. In some embodiments, the sequential process steps shown in FIGS. 5B and 5C are repeated for a plurality of cycles (e.g., 1 to 40 cycles) to selectively deposit a low-k dielectric film 530 of up to 20 nm on the dielectric layer 510.

[0047] Due to the periodic and sequential nature of the spiCVD process, it is possible to selectively deposit a uniform low-k dielectric film on the dielectric surface while avoiding contamination of non-target areas such as metal and metal oxide surfaces provided on the same substrate. In some embodiments, the spiCVD process described herein can be used to perform a single-step DoD (e.g., for FSAV manufacturing) without the need to passivate metal patterns with, for example, SAMs. Low-k dielectric materials such as poly(1,3,5-trimethyl-1,3,5-trivinylcyclotrisiloxane) (pV3D3) can be used for this purpose. Similar behavior is expected for other low-k dielectric polymers that can be deposited by spiCVD.

[0048] Selective Polymer-on-Metal (PoM) Deposition by Reversing Selectivity with Molecular Adsorbates During the manufacture of an IC, it may be desirable to selectively deposit a polymer layer on a metal surface in the presence of a dielectric surface. To achieve selective Polymer-on-Metal (PoM) deposition, the unique Polymer-on-Dielectric (PoD) selectivity described above and shown in FIGS. 5A - 5C can be reversed using molecular adsorbates such as, but not limited to, self-assembled monolayers.

[0049] As described above, a self-assembled monolayer (SAM) is an organic molecule that forms a regular surface monolayer coating on a material, thereby changing the chemical and / or physical properties of the material surface. SAM-forming molecules having thiol, amine, or carboxylic acid head groups have a higher chemical affinity for metal surfaces than for dielectric surfaces, so they selectively assemble on metals relative to dielectric materials. Thus, these SAM-forming molecules can be used to enable selective condensation of monomers on metal surfaces.

[0050] Figures 6A - 6D show an improved ASD process that can be used to selectively deposit a polymer thin film on a metal material in accordance with the present disclosure. More specifically, Figures 6A - 6E show an improved polymer-on-metal (PoM) process that uses spiCVD to selectively deposit a polymer thin film on a SAM passivated metal (or metal oxide) material while avoiding polymer deposition on non-target materials such as dielectric materials provided on the same substrate.

[0051] The spiCVD process shown in Figures 6A - 6D is similar to that shown in Figures 5A - 5C and generally can be initiated by providing a substrate 600 having a metal / dielectric pattern with a metal layer 605 and a dielectric layer 610 exposed on the surface of the substrate 600 in Figure 6A. The metal layer 605 and the dielectric layer 610 can each include a variety of materials, as described above with respect to Figure 5A. In one exemplary embodiment, the metal layer 605 can include a copper (Cu) material and the dielectric layer 610 can include an interlayer dielectric (ILD).

[0052] As described above, for precursor chemisorption, metal (or metal oxide) atoms present on the surface of the metal layer 605 tend to have a low chemical affinity, while -O, -H, or OH bonds on the surface of the dielectric layer 610 tend to have a high chemical affinity. Due to the difference in chemical affinity, the polymer deposited by chemical vapor deposition tends to selectively condense on the dielectric surface while avoiding the metal surface. However, the inherent selectivity for the dielectric surface can be reversed by using molecular adsorbates such as SAMs to modify the chemical and / or physical surface properties of the metal layer 605. As described in more detail below, the SAM formed on the metal or metal oxide surface can be used as a condensation medium for the gas-phase monomer precursor.

[0053] In the embodiment shown in FIG. 6B, a SAM structure 612 is formed on the surface of the metal layer 605 to modify the chemical and / or physical surface properties of the metal layer 605 and form a SAM-passivated metal or metal oxide. As is known in the art, SAM-forming molecules consist of a head group, a tail, and a functional end group. Self-assembled monolayers (or SAMs) are created by chemisorption of the head groups onto the target surface by either the gas phase or the liquid phase, followed by slow organization of the subsequent tail groups. Since the head groups have a high chemical affinity for the target surface, they gather together on the target surface, while the tail groups gather away from the target surface. The region of densely packed SAM-forming molecules nucleates and grows until the target surface is covered with a single self-assembled monolayer or SAM structure. Common head groups include thiols, amines, carboxylic acids, silanes, phosphonates, and the like. As described above, SAM-forming molecules having thiol, amine, and carboxylic acid head groups are known to have a high chemical affinity for metals and can thus be used to selectively assemble on the surface of the metal layer 605 to form the SAM structure 612. In one exemplary embodiment, a CH-type or CF-type thiol SAM structure 612 can be formed on the surface of the metal layer 605 by chemical vapor deposition.

[0054] In the embodiment shown in FIG. 6C, the surface of substrate 600 is exposed to vapor precursor (P) 615, which selectively condenses within and on SAM structure 612 to form a thin condensation layer 620 within / on SAM structure 612. In one embodiment, precursor 615 used in FIG. 6C can be GMA. However, precursor 615 is not strictly limited to GMA and can include other monomer precursors that (a) can be deposited by CVD and (b) can be initiated / activated by an initiator to achieve polymerization. Examples of other monomers are discussed in more detail above.

[0055] The SAM structure 612 formed on the surface of the metal layer 605 in FIG. 6B passivates the metal layer 605 by changing the chemical and physical properties of the metal surface. This passivation reverses the inherent polymer-on-dielectric (PoD) selectivity of the polymer deposition process, enabling the SAM structure 612 to function as a condensation medium for precursor 615 in FIG. 6C. In some embodiments, the vapor pressure and / or exposure time of precursor 615 can be carefully controlled to selectively condense the monomer precursor within and on SAM structure 612, thus providing a uniform ultrathin coating of condensation layer 620 within / on the SAM passivated metal layer 605 before the initiator is introduced in FIG. 6D.

[0056] In the embodiment shown in FIG. 6D, the surface of substrate 600 is subsequently exposed to initiator (I) 625, which reacts with and polymerizes condensation layer 620 to form an ultrathin (e.g., 1 - 2 nm or less) polymer film 630 within / on the SAM passivated metal layer 605. In one embodiment, TBPO can be used to initiate the polymerization of GMA to form a pGMA polymer film. However, initiator 625 is not strictly limited to TBPO and can include other initiators that can initiate the polymerization of condensation layer 620 in FIG. 6D. Examples of other initiators that can be used in FIG. 6D are discussed in more detail above.

[0057] After the polymer film 630 is first formed on the SAM-passivated metal layer 605, the process of sequentially exposing the surface of the substrate 600 to the precursor 615 in FIG. 6C and to the initiator 625 in FIG. 6D can be repeated over one or more spiCVD cycles until the desired amount (or predetermined thickness) of the polymer film 630 is selectively deposited on the SAM-passivated metal layer 605. In some embodiments, the sequential process steps shown in FIGS. 6C and 6D can be repeated for a plurality of cycles (e.g., 3 to 6 cycles) to selectively deposit a polymer film 630 of up to 3 nm on the SAM-passivated metal layer 605.

[0058] In some embodiments, the number of cycles required to effectively coat the SAM-passivated metal layer 605 while avoiding contamination of the dielectric layer 610 can be selected from a selectivity window. This selectivity window can be obtained from experimental results and can be determined, for example, based on the polymer growth rates achieved for each spiCVD cycle on the target (SAM-passivated metal) and non-target (dielectric) surfaces. FIGS. 7A - 7B show one method for determining the selectivity window between the SAM-passivated copper layer and the interlayer dielectric (ILD) surface. A similar method can be used to determine the selectivity window for depositing the polymer on other target and non-target surfaces. Once the selectivity window is determined for a particular pattern, it can be used to maintain selectivity throughout the polymer deposition process.

[0059] Graphs 700 and 750 shown in FIGS. 7A - 7B show the experimental results obtained to determine the selectivity window for pGMA deposition by spiCVD on a pattern containing ILD and SAM - passivated copper lines. The graph 700 shown in FIG. 7A shows pGMA growth (represented in nm) versus GMA exposure time (represented in seconds) for 1 cycle of spiCVD. The graph 750 shown in FIG. 7B shows pGMA growth (represented in nm) versus spiCVD cycles (represented by the number of cycles) for the pGMA film deposited on the ILD and SAM - passivated copper lines. The experimental results shown in FIGS. 7A - 7B show that pGMA is selectively deposited on the SAM - passivated copper lines up to a threshold number of spiCVD cycles (e.g., up to 6 cycles maximum). After this threshold, further polymer deposition leads to contamination of the dielectric surface and loss of selectivity.

[0060] As shown in FIG. 7B, using the selectivity window of 3 - 6 spiCVD cycles, up to about 3 nm of pGMA can be deposited on the SAM - passivated copper lines without significantly contaminating the ILD surface. Beyond this selectivity window, the selectivity between the SAM - passivated copper lines and the ILD surface decreases, which may allow the polymer to deposit on the dielectric surface. In some embodiments, by passivating the dielectric layer 610, the selectivity can be improved outside the selectivity window.

[0061] In the embodiments shown in FIGS. 6A - 6D, the inherent polymer - on - dielectric (PoD) selectivity of the polymer deposition process is reversed by forming a SAM structure 612 on the surface of the metal layer 605 before exposing the substrate to the precursor 615. The SAM structure 612 reverses the inherent PoD selectivity of the polymer deposition process and allows the polymer precursor 615 to selectively condense within and on the SAM structure 612. The formation of condensation on the surface of the dielectric layer 610 is avoided by selecting the number of cycles required to effectively coat the metal layer 605 with the SAM structure 612 from a predetermined selectivity window, as shown, for example, in FIG. 7B.

[0062] It is hypothesized that a combination of chemical and physical forces can contribute to the reversal of the above selectivity mechanism. Due to the weakness of their interactions (e.g., mainly van der Waals forces and hydrogen bonds), the SAM-forming molecules deposited on the metal surface present a significant amount of subsurface free volume, while the defects of SAM molecules (due to incomplete surface coverage) compensate for high aspect ratio sub-nano-sized pinholes. These volumes enable an increase in the residence time of the incoming monomers, thus artificially reducing its surface saturation pressure, resulting in preferential monomer condensation on the SAM structure 612 with respect to the surface of the dielectric layer 610. The chemical affinity of the precursor 615 for the SAM structure 612 further results in the dewetting of any residual monomers from the surface of the dielectric layer 610, further enhancing the selectivity. However, the selectivity of the polymer deposition process also depends on the thickness of the deposited polymer film 630. As described above, the selectivity can be maintained by selecting the polymer deposition thickness within a determined selectivity window for a specific pattern.

[0063] As shown in FIGS. 5-6, the ASD process described above offers various advantages over conventional ASD techniques. For example, the ASD process utilizes spiCVD to selectively deposit a polymer thin film on various target materials including dielectric materials, metal and metal oxide materials, and SAM passivated metals / metal oxides. By using spiCVD, it is possible to provide highly reproducible, uniform, and thermally and mechanically stable 2D polymer thin films using the ASD process described herein. Due to the sequential nature of spiCVD, it enables controlled coating of an ultra-thin amount (e.g., 1-2 nm or less) of polymer on the target material. In some embodiments, the amount of polymer selectively deposited on the target material per spiCVD cycle can be controlled by varying the precursor exposure time, precursor vapor pressure, temperature, and / or surface properties of the target material. Thus, spiCVD can be used in the ASD process described herein to finely tune the amount of polymer deposited on the target material and can sometimes be used to provide control of the polymer deposition process at the angstrom (Å) level. The periodic nature of spiCVD provides a more uniform deposition of the polymer film on the target material, while the precursor promotes deposition selectivity by enabling area-selective deposition in patterns of materials with different wetting properties.

[0064] The ASD process described herein can be utilized in a variety of applications. For example, the ASD process shown in FIGS. 5A - 5C can be used to provide selective polymer - on - dielectric (PoD) deposition having an excellent vertical profile in the pattern of inter - layer dielectric (ILD) and copper (Cu) lines. Similar selectivity is expected for other metal and metal - oxide surfaces such as, but not limited to, ruthenium (Ru), cobalt (Co), tungsten (W), molybdenum (Mo), and their oxides. In some embodiments, the ASD process shown in FIGS. 5A - 5C can alternatively be used to provide selective dielectric - on - dielectric (DoD) deposition by replacing the monomer precursor used in FIG. 5B with a low - k dielectric precursor (e.g., pV3D3 or the like). Additionally, the ASD process shown in FIGS. 6A - 6D can be used to provide selective polymer - on - metal (PoM) deposition by using a SAM structure as a nucleation promoter. The SAM structure used in these embodiments functions as a condensation medium for the monomer precursor and reverses the inherent PoD selectivity by promoting selective polymer growth on the metal surface relative to the dielectric surface.

[0065] In addition to selective PoD, DoD, and PoM, the selectivity provided by the ASD process described herein can be extended to selectively form polymer thin films in a variety of other materials and patterns such as, for example, carbon hard mask (HM) and extreme ultraviolet (EUV) photoresist (PR) patterns. The ASD process described herein can also be used to provide nanoscale masks, dummy structures, and removable templates. Using the techniques described herein, polymer thin films can be selectively deposited on various target surfaces with relatively easy application and removal. For example, the polymer thin films can be removed by gentle oxidation, thermal decomposition, hydrogen (H2) plasma, etc. Other advantages may be apparent to those skilled in the art.

[0066] Selective Dielectric - on - Dielectric (DoD) Deposition by SAM Immobilization Selective dielectric-on-dielectric (DoD) growth is one approach that can be used to ensure the reliability in manufacturing fully self-aligned vias (FSAV) in the back-end-of-line (BEOL). Currently available DoD processes use self-assembled monolayers (SAMs) to passivate metal lines (e.g., copper lines) and enable selective dielectric growth on the interlayer dielectric (ILD) patterns. Unfortunately, SAMs have the drawback of low thermal, mechanical, and shelf-life stability, which reduces their effectiveness for selective DoD applications.

[0067] As described above, SAM-forming molecules can rearrange, desorb, and even migrate to adjacent dielectric patterns during processing or long-term storage, pulling metal impurities along (see, e.g., Fig. 1B). These events impair the ability of SAMs to effectively enable selective DoD without reliability concerns. Defects in SAMs can also result in incomplete blanket coverage of metal features, which can cause dielectric materials to grow on the metal features and raise further reliability concerns. Finally, SAMs are only a few nanometers thick and have a flexible nature, making them not ideal for inducing vertical growth of dielectric patterns in selective DoD applications. This leads to rapid growth of dielectric materials on metal features, as shown in Fig. 1B, thus compromising the critical dimensions of the patterns.

[0068] SAM Stabilization with a Polymer Topcoat to Improve the Selective Dielectric-on-Dielectric (DoD) Process In addition to providing an improved ASD process and method for depositing a polymer thin film on both a dielectric and a metal surface, the present disclosure also provides an improved process and method for stabilizing a self-assembled monolayer (SAM) deposited on a target surface. In the present disclosure, a cyclic vapor deposition process is used to selectively deposit (or coat) a polymer thin film on the SAM structure. In at least one preferred embodiment, the spiCVD process is used to selectively deposit a polymer thin film on the SAM structure, thus providing a polymer top coat on the SAM. The term "top coat" is used herein to describe the deposited polymer, but does not necessarily mean that the polymer is deposited or coated only on the upper surface of the SAM structure. Instead, a portion of the polymer may interlock with them within the SAM-forming molecules. The degree of interlocking and the degree of top coating can depend on various factors such as the density of the SAM, the chemical structures of the SAM and the polymer, and the amount of polymer applied to the SAM.

[0069] As described in more detail below, the polymer topcoat approach not only stabilizes the SAM structure but also repairs any defects in the SAM structure initially formed on the target surface. In some embodiments, the polymer topcoat approach can be used to reduce or eliminate reliability concerns that typically arise when SAMs are used in selective DoD applications. In addition to providing excellent blanket coverage on metal lines, the polymer topcoat approach described herein effectively mitigates all of the reliability issues presented above. For example, the polymer topcoat improves the thermal and storage stability of the SAM structure by strengthening the SAM structure. The polymer topcoat also forms an interlocking blanket within and on the SAM structure, thus further enhancing its ability to prevent dielectric nuclei from reaching the metal surface in DoD applications. Finally, the polymer topcoat provides a SAM structure with a thicker and more rigid structure, thereby enabling better vertical growth of the dielectric and preventing rapid growth of the dielectric material on the metal lines.

[0070] Figures 8A - 8E illustrate an improved process for stabilizing a self - assembled monolayer (SAM) structure in accordance with the present disclosure. More specifically, Figures 8A - 8E illustrate an improved process that utilizes spiCVD to selectively deposit a polymer thin film within / on the SAM structure, thereby stabilizing the SAM structure with a polymer topcoat. In the embodiments shown in Figures 8A - 8E, the polymer thin film is selectively deposited on the SAM passivated metal surface to (a) repair defects in the SAM structure and provide a blanket coverage on the metal surface, (b) prevent SAM - forming molecules from migrating to an adjacent dielectric surface, and (c) increase the thickness and rigidity of the SAM structure to induce vertical growth of a dielectric pattern subsequently formed on the dielectric surface. Although described in the context of DoD applications, the processes described herein can also be used to stabilize SAM assemblies utilized in other applications.

[0071] Similar to the previous embodiments, the embodiment shown in FIG. 8A can be initiated by providing a metal / dielectric pattern having a metal layer 805 and a dielectric layer 810 exposed on the surface of a substrate 800 to the substrate 800. The metal layer 805 and the dielectric layer 810 can each include a variety of materials, as described above with respect to FIG. 5A. In one exemplary embodiment, the metal layer 805 can include a copper (Cu) material, and the dielectric layer 810 can include an interlayer dielectric (ILD) material.

[0072] In the embodiment shown in FIG. 8B, a SAM structure 812 is formed on the surface of the metal layer 805. In one exemplary embodiment, a CH-type or CF-type thiol SAM structure 812 can be formed on the surface of the metal layer 805 by chemical vapor deposition. As shown in FIG. 8B, the SAM structure 812 formed on the surface of the metal layer 805 is a thin layer of SAM-forming molecules (i.e., a single monolayer), and may often have defects that prevent the SAM structure 812 from completely covering the metal surface. To repair the defects and increase the thickness and rigidity of the SAM structure 812, a polymer top coat can be selectively deposited within / on the SAM structure 812, as shown in FIGS. 8C-8D and described in more detail below.

[0073] In the embodiment shown in FIG. 8C, the surface of the substrate 800 is exposed to a vapor-phase precursor (P) 815, which selectively condenses within and on the SAM structure 812 to form a condensed layer 820 within and on the SAM structure 812. In one embodiment, the precursor 815 used in FIG. 8C can be GMA. However, the precursor 815 is not strictly limited to GMA and can include other monomer precursors that (a) can be deposited by CVD and (b) can be initiated / activated by an initiator to achieve polymerization. Examples of other monomer precursors that can be used in FIG. 8C have been discussed in more detail above. In some embodiments, the vapor pressure and exposure time of the precursor 815 can be carefully controlled to selectively condense the monomer within and on the SAM structure 812 before the initiator is introduced in FIG. 8D.

[0074] In the embodiment shown in FIG. 8D, the surface of the substrate 800 is subsequently exposed to an initiator (I) 825, which reacts with the condensation layer 820 and polymerizes it to form an ultra-thin (e.g., 1-2 nm or less) polymer film 830 that interlocks with the SAM structure 812. In one embodiment, TBPO can be used to initiate the polymerization of GMA to form a pGMA polymer film. However, the initiator 825 is not strictly limited to TBPO and can include other initiators that can initiate the polymerization of the condensation layer 820. Examples of other initiators that can be used in FIG. 8D are discussed in more detail above.

[0075] After the polymer film 830 is first formed on the SAM structure 812, the process of sequentially exposing the surface of the substrate 800 to the precursor 815 in FIG. 8C and the initiator 825 in FIG. 8D can be repeated over one or more cycles of the spiCVD process described herein until the desired amount (or predetermined thickness) of the polymer film 830 is selectively deposited within / on the SAM structure 812. In some embodiments, the sequential process steps shown in FIGS. 8C and 8D can be repeated for multiple cycles (e.g., 3-10 cycles) to selectively deposit a polymer film 830 up to 5 nm on the SAM structure 812.

[0076] In some embodiments, the number of cycles required to topcoat the SAM structure 812 with the polymer film 830 without contaminating the dielectric layer 810 can be included within a selectivity window that can be determined, for example, based on the polymer growth rate achieved per spiCVD cycle on the target (SAM) and non-target (dielectric) surfaces. FIGS. 7A-7B show one method for determining the selectivity window between the SAM passivated copper layer and the interlayer dielectric (ILD) surface. Similar methods can be used to determine the selectivity window for depositing polymers on other target and non-target surfaces. Once the selectivity window is determined for a particular pattern, it can be used to maintain selectivity throughout the polymer deposition process.

[0077] In the embodiment shown in FIG. 8E, the dielectric material 835 is deposited on the surface of the dielectric layer 810 by chemical vapor deposition or atomic layer deposition. In some embodiments, the dielectric material 835 can be deposited by exposing the surface of the substrate to a dielectric precursor, which reacts with and bonds to the surface of the dielectric layer 810 to selectively deposit the dielectric material 835 on the surface of the dielectric layer 810. In some embodiments, the dielectric precursor can be a precursor of a low-k dielectric material such as one based on polysiloxane. In the case of chemical vapor deposition or atomic layer deposition, the precursor can be oxidized by an oxidizing agent to form an oxide (i.e., a dielectric). Operating parameters such as vapor pressure, dielectric precursor exposure time, temperature, etc. can be controlled to deposit a dielectric material 835 of a predetermined thickness on the surface of the dielectric layer 810.

[0078] As shown in FIG. 8E, the polymer film 830 formed within / on the SAM structure 812 (a) repairs defects in the SAM structure 812 and provides a blanket coating over the surface of the metal layer 805, (b) prevents SAM-forming molecules from migrating to the surface of the adjacent dielectric material 835, and (c) increases the thickness and rigidity of the SAM structure 812 to induce vertical growth of the dielectric material 835 and prevent rapid growth of the dielectric material 835 over the metal layer 805, thereby stabilizing the SAM structure 812.

[0079] As shown in FIGS. 8A-8E, experiments were conducted to selectively deposit a pGMA film on a patterned substrate containing silicon dioxide (SiO2) and SAM-passivated copper (Cu) line patterns using the spiCVD process described above. In one experiment, the spiCVD process was used to deposit pGMA on the SAM-passivated copper lines by first exposing the substrate surface to the GMA precursor to form a condensation layer on the SAM-passivated copper lines. The GMA precursor was supplied to the substrate surface at a vapor pressure of about 1 torr and a temperature of 160° C. to 170° C. When the substrate was exposed to the GMA precursor, the GMA precursor selectively condensed within and on the SAM structure due to a combination of chemical and van der Waals interactions. The precursor condensation layer was subsequently polymerized by the introduction of TBPO, which initiated GMA polymerization, to form a pGMA top coat that interlocked with the SAM structure. Careful control of the GMA vapor pressure and exposure time enabled selective polymer top coating of the SAM and fine-tuning of the SAM top coat amount.

[0080] The polymer top coat approach was tested using thiol-based SAMs with various tail functional groups (such as hydrocarbons and halogens), and the results were nearly identical. This demonstrates the generality of the approach regardless of the chemical nature of the SAM. Thus, the polymer top coat approach described herein and shown in FIGS. 8A-8E is expected to function with any molecular surface coating that enables selective condensation / polymerization during spiCVD.

[0081] Graph 900 shown in FIG. 9 shows the experimental results obtained to evaluate the process shown in FIGS. 8A - 8E. More specifically, graph 900 shows the AFM surface line scan of a patterned substrate containing ILD and SAM - passivated copper lines after (a) performing chemical - mechanical polishing (CMP) of the patterned surface, (b) forming a CH - type thiol SAM structure on the copper lines, and (c) depositing a pGMA thin film within / on the SAM structure using the process shown in FIGS. 8A - 8D and stabilizing the SAM structure. The AFM line scan shown in FIG. 9 shows the height profile (represented in nm) obtained from the patterned substrate after each of the above - mentioned process steps. The AFM line scan demonstrates that the pGMA polymer film can be selectively deposited on the SAM - passivated copper lines without depositing the polymer on the ILD lines.

[0082] Region - selective polymer top - coating of the SAM structure requires minimal polymer nucleation on the adjacent dielectric surface. Avoiding polymer deposition on the dielectric surface is particularly important for DoD applications because any polymer residue can prevent the DoD process. The region - selectivity of the polymer top - coating process presented above benefits from the selective condensation of the polymer precursor within / on the SAM structure with respect to the dielectric surface. In some embodiments, the selectivity window of the polymer top - coating process can be wide enough to coat up to 3 nm of polymer on the SAM structure without overly contaminating the dielectric surface and can thus be utilized for DoD applications.

[0083] As described above, the polymer top coat stabilizes the SAM structure by (a) repairing defects in the SAM structure and providing a blanket coating over the surface of the metal layer, (b) preventing SAM-forming molecules from migrating to the surface of adjacent dielectric materials, and (c) increasing the thickness and rigidity of the SAM structure. The stabilized SAM structure was tested for thermal and storage stability and shown to be stable at high temperatures up to 250 °C and exhibit storage stability for up to four weeks. Higher temperatures and longer storage lifetimes were not evaluated, but an extension of thermal and storage stability is expected.

[0084] In conventional DoD applications, the SAM coating of the metal surface in a dielectric / metal pattern is intended to enable area-selective DoD by suppressing dielectric growth on the metal surface. DoD is typically carried out using deposition methods such as CVD and ALD. In such methods, the SAM structure suppresses dielectric growth on the metal surface by preventing the precursor from reaching the metal surface. Furthermore, the hydrophobicity of the SAM tail repels water, which is a co-reactant in the oxide ALD formulation.

[0085] In the present disclosure, the polymer top coat applied to the SAM not only improves precursor suppression of the SAM structure by forming a denser and more stable structure, but also repairs any defects in the SAM structure initially formed on the pattern. However, hydrophilic polymers may ultimately result in unwanted ALD nucleation. Therefore, it is essential to provide a hydrophobic surface for DoD applications. This can be achieved by either: 1) using a hydrophobic polymer for the top coating, or 2) further modifying the polymer-top-coated SAM with a second hydrophobic layer such as another SAM or functional molecule.

[0086] As shown in FIGS. 8A-8D, the polymer topcoat approach described above provides various advantages over the prior art. For example, the polymer topcoat process described above can be used to provide selective SAM stabilization and defect repair by the polymer for area-selective DoD. In some embodiments, the process steps shown in FIGS. 8A-8E can be performed in the same deposition chamber or processing tool. This reduces the need for multi-step SAM application and residue removal, improves yield, shortens process time, and provides versatility.

[0087] As described above, the polymer topcoat applied to the SAM structure enhances the thermal, physical, and chemical stability of the SAM structure. This allows the SAM to be used in various applications (such as DoD) where the use of SAM is typically limited by the stability and defects of the SAM. The SAM can also be used in various other applications. For example, when used as a spiCVD nucleation promoter, an "incomplete" SAM can be used to drive selective polymer growth on the SAM-coated surface. The polymer topcoated SAM can also be used as an ALD nucleation mask by shielding the underlying substrate from contamination by ALD nuclei and defects.

[0088] The polymer topcoat process shown in FIGS. 8A - 8D utilizes spiCVD to selectively coat very small amounts of polymer (e.g., a few angstroms) within / on a SAM structure in a cyclic process where the surface of a substrate is sequentially exposed to a monomer precursor to selectively form a thin condensate film on the SAM structure, and then the surface of the substrate is exposed to an initiator which polymerizes the condensate film to form a polymer thin film within / on the SAM structure. The amount of polymer selectively formed within / on the SAM structure can be adjusted by repeating the steps of sequentially exposing the surface of the substrate to the monomer precursor and the initiator over one or more spiCVD cycles, and can be fine - tuned by controlling the vapor pressure of the monomer precursor, the precursor exposure time, and the number of spiCVD cycles. Other advantages may be apparent to those skilled in the art.

[0089] FIGS. 10 - 13 show exemplary methods of selectively depositing a polymer thin film on various target materials including dielectric materials, metal and / or metal oxide materials, and self - assembled monolayer (SAM) assemblies using the techniques described herein. The embodiments of FIGS. 10 - 13 are merely illustrative, and it will be understood that additional methods may utilize the techniques described herein. Further, since the described processing steps are not intended to be exclusive, additional steps may be added to the methods shown in FIGS. 10 - 13. Further, the order of steps is not limited to the order shown in the drawings since different orders may occur and / or various steps may be combined or performed simultaneously.

[0090] FIG. 10 shows one embodiment of a method 1000 that can be used for area-selective deposition (ASD) of a polymer film in accordance with the present disclosure. The method 1000 can generally be initiated by providing a substrate having a target material and a non-target material exposed on the surface of the substrate (step 1010). Next, the method 1000 is to expose the surface of the substrate to a vapor-phase precursor, where the vapor-phase precursor chemically reacts with and binds to the surface of the target material while avoiding the formation of condensates on the non-target material, and selectively forms a condensate layer on the surface of the target material (step 1020), and subsequently, after the condensate layer is selectively formed on the surface of the target material, the surface of the substrate is exposed to a vapor-phase initiator (step 1030). When the vapor phase is introduced (step 1030), the vapor-phase initiator reacts with the condensate layer and polymerizes it to selectively deposit a polymer film on the surface of the target material.

[0091] The surface of the substrate is first exposed to the vapor-phase precursor for a precursor exposure time (step 1020), and then the surface of the substrate is subsequently exposed to the vapor-phase initiator (step 1030). In some embodiments, the method 1000 can further include controlling the thickness of the polymer film by varying at least one of the precursor exposure time and the vapor pressure of the vapor-phase precursor (step 1020).

[0092] In some embodiments, method 1000 may further include repeating, for a predetermined number of cycles, the step of exposing the surface of the substrate to a vapor-phase precursor (step 1020) and subsequently the step of exposing the surface of the substrate to a vapor-phase initiator (step 1030) to selectively deposit a polymer film of a predetermined thickness on the surface of the target material without contaminating non-target materials with the polymer. In some embodiments, method 1000 may further include controlling the amount of polymer film selectively deposited on the target material per cycle by changing at least one of the precursor exposure time and the vapor pressure of the vapor-phase precursor. In some embodiments, the amount of polymer film selectively deposited on the target material per cycle may be less than 2 nm, and by repeating steps 1020 and 1030 for a predetermined number of cycles (e.g., 10 to 40 cycles), a polymer film up to 20 nm can be selectively deposited on the surface of the target material without contaminating non-target materials with the polymer.

[0093] In some embodiments, additional steps may be performed before exposing the surface of the substrate to the vapor-phase precursor (step 1020). For example, method 1000 may further include (a) determining a selectivity window based on the polymer growth rate achieved per cycle on the target material and on the non-target material, and (b) selecting, from within the selectivity window, a predetermined number of cycles required to selectively deposit a polymer film of a predetermined thickness on the surface of the target material without contaminating the non-target material with the polymer.

[0094] The method 1000 shown in FIG. 10 can be used for area-selective deposition (ASD) of a polymer film on a target material while avoiding contamination of non-target materials formed on the same substrate. Examples of target materials include, but are not limited to, dielectric materials, metal or metal oxide materials, and SAM-passivated metals or metal oxides. The non-target materials formed on the same substrate preferably have wetting characteristics different from those of the target materials. In some embodiments, the target material can be a dielectric material and the non-target material can be a metal or metal oxide material. In other embodiments, the target material can be a metal or metal oxide material and the non-target material can be a dielectric material.

[0095] In some embodiments of method 1000, a polymer film can be selectively deposited on a dielectric material by exposing the surface of the substrate to a monomer precursor (step 1020), followed by exposing the surface of the substrate to a vapor-phase initiator (step 1030). The monomer precursor chemically reacts with and binds to the surface of the dielectric material to selectively form a monomer condensate layer on the surface of the dielectric material while avoiding the formation of condensates on the metal or metal oxide material. When the vapor-phase initiator is introduced (step 1030), the vapor-phase initiator reacts with and polymerizes the monomer condensate layer to selectively deposit a polymer film on the surface of the dielectric material.

[0096] In some embodiments of method 1000, exposing the surface of the substrate to a vapor-phase precursor includes exposing the surface of the substrate to a dielectric precursor (step 1020), followed by exposing the surface of the substrate to a vapor-phase initiator (step 1030), whereby a dielectric film can be selectively deposited on a dielectric material. The dielectric precursor chemically reacts with and binds to the surface of the dielectric material to selectively form a dielectric condensate layer on the surface of the dielectric material while avoiding the formation of condensates on the metal or metal oxide material. When the vapor-phase initiator is introduced (step 1030), the vapor-phase initiator reacts with and polymerizes the dielectric condensate layer to selectively deposit a dielectric film on the surface of the dielectric material.

[0097] In some embodiments of method 1000, the polymer film can be selectively deposited on a SAM-passivated metal or metal oxide. Prior to exposing the surface of the substrate to the vapor-phase precursor (step 1020), method 1000 can further include forming a self-assembled monolayer (SAM) on the surface of the metal or metal oxide material to modify the chemical and / or physical surface properties of the metal or metal oxide material and form a SAM-passivated metal or metal oxide. Once the SAM-passivated metal or metal oxide is formed, method 1000 can expose the surface of the substrate to the monomer precursor (step 1020) and subsequently expose the surface of the substrate to a vapor-phase initiator (step 1030). The monomer precursor selectively condenses on the SAM while avoiding the formation of condensates on the dielectric material to form a monomer condensation layer on the SAM-passivated metal or metal oxide. When the vapor-phase initiator is introduced (step 1030), the vapor-phase initiator reacts with and polymerizes the monomer condensation layer to selectively deposit a polymer film on the SAM-passivated metal or metal oxide.

[0098] FIG. 11 shows another embodiment of a method 1100 that can be used for area-selective deposition (ASD) of a polymer film in accordance with the present disclosure. Method 1100 can generally be initiated by providing a substrate having a target material and a non-target material exposed on a surface of the substrate (step 1110). Next, method 1100 can include sequentially exposing the surface of the substrate to a vapor-phase precursor and a vapor-phase initiator such that the surface of the substrate is first exposed to the vapor-phase precursor for a precursor exposure time and then subsequently the surface of the substrate is exposed to the vapor-phase initiator (step 1120). When the vapor-phase precursor is first introduced (step 1120), the vapor-phase precursor chemically reacts with and binds to the surface of the target material while avoiding formation of condensates on the non-target material to selectively form a condensate layer on the surface of the target material. When the vapor-phase initiator is subsequently introduced (step 1120), the vapor-phase initiator reacts with and polymerizes the condensate layer to selectively deposit a polymer film on the surface of the target material. Next, method 1100 can include repeating the step of sequentially exposing the surface of the substrate to the vapor-phase precursor and the vapor-phase initiator for a predetermined number of cycles to selectively deposit a polymer film of a predetermined thickness on the surface of the target material without contaminating the non-target material with the polymer (step 1130).

[0099] In some embodiments, method 1100 can further include controlling the amount of the polymer film selectively deposited on the target material per cycle by changing at least one of the precursor exposure time and the vapor pressure of the vapor-phase precursor. In some embodiments, the amount of the polymer film selectively deposited on the target material per cycle can be less than 2 nm, and step 1130 can be repeated for a predetermined number of cycles (e.g., 10 to 40 cycles) to selectively deposit a polymer film of up to 20 nm on the surface of the target material without contaminating the non-target material with the polymer.

[0100] In some embodiments, additional steps may be performed before sequentially exposing the surface of the substrate to the vapor precursor and the vapor initiator (step 1120). For example, method 1100 may further include: (a) determining a selectivity window based on the polymer growth rate achieved per cycle on the target material and on the non-target material; and (b) selecting, from within the selectivity window, a predetermined number of cycles required to selectively deposit a polymer film of a predetermined thickness on the surface of the target material without contaminating the non-target material with the polymer.

[0101] Similar to method 1000, method 1100 shown in FIG. 11 can be used for area-selective deposition (ASD) of a polymer film on a target material while avoiding contamination of non-target materials formed on the same substrate. Examples of target materials include, but are not limited to, dielectric materials, metal or metal oxide materials, and SAM-passivated metals or metal oxides. The non-target materials formed on the same substrate preferably have wetting properties different from those of the target material. In some embodiments, the target material can be a dielectric material and the non-target material can be a metal or metal oxide material. In other embodiments, the target material can be a metal or metal oxide material and the non-target material can be a dielectric material.

[0102] In some embodiments of method 1100, the polymer film can be selectively deposited on the dielectric material. In such embodiments, step 1120 can include (a) first exposing the surface of the substrate to a monomer precursor, where the monomer precursor chemically reacts with and binds to the surface of the dielectric material while avoiding the formation of condensates on the metal or metal oxide material, thereby selectively forming a monomer condensation layer on the surface of the dielectric material, and (b) subsequently exposing the surface of the substrate to a gas-phase initiator to polymerize the monomer condensation layer and selectively deposit a polymer film on the surface of the dielectric material. In some embodiments, the monomer precursor can be selected from the group consisting of glycidyl methacrylate (GMA), alkyl acrylate, alkylcyclosiloxane, perfluoroalkyl ethyl methacrylate, and trivinyltrimethoxycyclotrisiloxane, but is not limited thereto, and the gas-phase initiator can be selected from the group consisting of tert-butyl peroxide (TBPO), perfluorooctanesulfonyl fluoride, triethylamine, and organic peroxides, but is not limited thereto. In one exemplary embodiment, the gas-phase precursor can be glycidyl methacrylate (GMA), and the gas-phase initiator can be tert-butyl peroxide (TBPO).

[0103] In some embodiments of method 1100, the dielectric film can be selectively deposited on the dielectric material. In such embodiments, step 1120 can include (a) first exposing the surface of the substrate to a dielectric precursor, where the dielectric precursor chemically reacts with and binds to the surface of the dielectric material while avoiding the formation of condensates on the metal or metal oxide material, thereby selectively forming a dielectric condensation layer on the surface of the dielectric material, and (b) subsequently exposing the surface of the substrate to a gas-phase initiator to polymerize the dielectric condensation layer and selectively deposit a dielectric film on the surface of the dielectric material. In some embodiments, the dielectric precursor can be a precursor of a low-k dielectric material, and the gas-phase initiator can be tert-butyl peroxide (TBPO), perfluorooctanesulfonyl fluoride, triethylamine, or an organic peroxide.

[0104] In some embodiments of method 1100, the polymer film can be selectively deposited on a SAM-passivated metal or metal oxide. Prior to sequentially exposing the surface of the substrate to the vapor-phase precursor and the vapor-phase initiator (step 1120), method 1100 can further include forming a self-assembled monolayer (SAM) structure on the surface of the metal or metal oxide material to modify the chemical and / or physical surface properties of the metal or metal oxide material and form a SAM-passivated metal or metal oxide. Once the SAM-passivated metal or metal oxide is formed, method 1100 can sequentially expose the surface of the substrate to the vapor-phase precursor and the vapor-phase initiator by: (a) first exposing the surface of the substrate to a monomer precursor, which selectively condenses on the SAM structure while avoiding the formation of condensates on the dielectric material to form a monomer condensation layer on the SAM-passivated metal or metal oxide; and (b) subsequently exposing the surface of the substrate to a vapor-phase initiator to polymerize the monomer condensation layer and selectively deposit a polymer film on the SAM-passivated metal or metal oxide.

[0105] FIG. 12 shows an embodiment of a method 1200 that can be used to stabilize a self-assembled monolayer (SAM) structure in accordance with the present disclosure. Method 1200 generally begins by providing a substrate having a target material and a non-target material exposed on a surface of the substrate (step 1210) and forming a SAM structure on the surface of the target material (step 1220). Next, method 1200 includes exposing the surface of the substrate to a vapor-phase precursor, where the vapor-phase precursor selectively condenses on the SAM structure to form a condensed layer on the SAM structure (step 1230), and subsequently, after the condensed layer is selectively formed on the SAM structure, exposing the surface of the substrate to a vapor-phase initiator (step 1240). When the vapor-phase initiator is introduced (step 1240), the vapor-phase initiator reacts with and polymerizes the condensed layer to form a polymer film on the SAM structure. When method 1200 is used, the polymer film stabilizes the SAM structure by (a) repairing defects in the SAM structure and providing a blanket coating on the target material, (b) preventing SAM-forming molecules from migrating to adjacent non-target material surfaces, and (c) increasing the thickness and rigidity of the SAM structure.

[0106] In some embodiments, step 1230 of exposing the surface of the substrate to the vapor-phase precursor and step 1240 of subsequently exposing the surface of the substrate to the vapor-phase initiator are performed using a sequential pulse-initiated chemical vapor deposition (spiCVD) process. In such a process, the surface of the substrate is first exposed to the vapor-phase precursor for a precursor exposure time, and then the surface of the substrate is subsequently exposed to the vapor-phase initiator.

[0107] In some embodiments, the substrate can be provided within a processing tool (step 1210), and the step of forming the SAM structure (step 1220), the step of exposing the surface of the substrate to the vapor-phase precursor (step 1230), and the step of subsequently exposing the surface of the substrate to the vapor-phase initiator (step 1240) can each be performed within the same processing tool.

[0108] In some embodiments, method 1200 may further include repeating, for a predetermined number of cycles, the step of exposing the surface of the substrate to a vapor-phase precursor (step 1230) and the step of subsequently exposing the surface of the substrate to a vapor-phase initiator (step 1240) to selectively deposit a polymer film of a predetermined thickness on the SAM structure without contaminating non-target materials with the polymer.

[0109] In some embodiments, method 1200 may further include controlling the amount of the polymer film selectively deposited on the SAM structure for each cycle by changing at least one of the precursor exposure time and the vapor pressure of the vapor-phase precursor. In some embodiments, the amount of the polymer film selectively deposited on the SAM structure for each cycle may be less than 2 nm, and steps 1230 and 1240 are repeated for a predetermined number of cycles (e.g., 1 to 6 cycles) to selectively deposit a polymer film of up to 3 nm in and on the SAM structure without contaminating non-target materials with the polymer.

[0110] In some embodiments, additional steps may be performed before exposing the surface of the substrate to the vapor-phase precursor (step 1230). For example, method 1200 may further include (a) determining a selectivity window based on the polymer growth rate achieved for each cycle on the SAM structure and on non-target materials, and (b) selecting, from within the selectivity window, a predetermined number of cycles required to selectively deposit a polymer film of a predetermined thickness on the SAM structure without contaminating non-target materials with the polymer.

[0111] The method 1200 shown in FIG. 12 can form a polymer film using various vapor-phase precursors and a vapor-phase initiator. In some embodiments, for example, the vapor-phase precursor can be a monomer precursor selected from the group consisting of, but not limited to, glycidyl methacrylate (GMA), alkyl acrylate, alkylcyclosiloxane, trivinyltrimethoxycyclotrisiloxane, and perfluoroalkyl ethyl methacrylate, and the vapor-phase initiator can be selected from the group consisting of, but not limited to, tert-butyl peroxide (TBPO), perfluorooctanesulfonyl fluoride, triethylamine, and organic peroxides. In one exemplary embodiment, the vapor-phase precursor can be glycidyl methacrylate (GMA), and the vapor-phase initiator can be tert-butyl peroxide (TBPO).

[0112] The method 1200 shown in FIG. 12 can be utilized to stabilize a SAM assembly formed on various materials. In some embodiments, for example, step 1220 of forming a SAM structure on the surface of the target material can include forming a SAM structure on a metal material, a hard mask material, or a photoresist material.

[0113] FIG. 13 shows one embodiment of a method 1300 that can be used to stabilize a self-assembled monolayer (SAM) structure utilized in a dielectric-on-dielectric (DoD) process in accordance with the present disclosure. The method 1300 generally begins by providing a substrate having a dielectric layer and a metal layer exposed on the surface of the substrate (step 1310), and forming a SAM structure on the surface of the metal layer (step 1320). Next, the method 1300 can include sequentially exposing the surface of the substrate to a vapor-phase monomer precursor and then a vapor-phase initiator (step 1330). When the vapor-phase monomer precursor is introduced (step 1330), the vapor-phase monomer precursor selectively condenses within the SAM structure to form a monomer condensation layer within the SAM structure. Subsequently, when the vapor-phase initiator is introduced (step 1330), the vapor-phase initiator reacts with and polymerizes the monomer condensation layer to form a polymer film that interlocks with the SAM structure. Next, the method 1300 can include repeating the step of sequentially exposing the surface of the substrate to a vapor-phase monomer precursor and then a vapor-phase initiator for a predetermined number of cycles to selectively deposit a polymer film of a predetermined thickness within and on top of the SAM structure without contaminating the dielectric layer with the polymer (step 1340).

[0114] In some embodiments, step 1330 of sequentially exposing the surface of the substrate to a vapor-phase monomer precursor and then a vapor-phase initiator can be performed using a sequential pulse initiation chemical vapor deposition (spiCVD) process. In such a process, the surface of the substrate is first exposed to the vapor-phase monomer precursor for a precursor exposure time, and then the surface of the substrate is subsequently exposed to the vapor-phase initiator (step 1330).

[0115] In some embodiments, method 1300 may further include controlling the amount of polymer film selectively deposited on the SAM structure per cycle by varying at least one of the precursor exposure time and the vapor pressure of the vapor-phase precursor. In some embodiments, the amount of polymer film selectively deposited on the SAM structure per cycle may be less than 2 nm, and step 1330 of sequentially exposing the surface of the substrate to the vapor-phase precursor and then the vapor-phase initiator is repeated a predetermined number of cycles (e.g., 10 to 40 cycles) (step 1340) to selectively deposit a polymer film up to 20 nm within and on top of the SAM structure without contaminating non-target materials with the polymer.

[0116] In some embodiments, additional steps may be performed before step 1330 of sequentially exposing the surface of the substrate to the vapor-phase monomer precursor and then the vapor-phase initiator. For example, method 1300 may further include (a) determining a selectivity window based on the polymer growth rate achieved per cycle on the SAM structure and on the dielectric layer, and (b) selecting from within the selectivity window the predetermined number of cycles required to selectively deposit a polymer film of a predetermined thickness within and on top of the SAM structure without contaminating the dielectric layer with the polymer.

[0117] As described above, the method 1300 shown in FIG. 13 can be used to stabilize the SAM structure utilized in a dielectric-on-dielectric (DoD) process. Thus, after a polymer film of a predetermined thickness is selectively deposited within and on top of the SAM structure (step 1340), additional steps can be performed. For example, the method 1300 can further include depositing a dielectric material on the surface of the dielectric layer. In some embodiments, the dielectric material can be deposited by exposing the surface of the substrate to a dielectric precursor, which reacts with and bonds to the surface of the dielectric layer to deposit the dielectric material on the surface of the dielectric layer. In some embodiments, the polymer film formed within and on top of the SAM structure (step 1340) can stabilize the SAM structure by (a) repairing defects in the SAM structure and providing a blanket coating over the metal layer, (b) preventing SAM-forming molecules from migrating to the dielectric material deposited on the surface of the dielectric layer, and (c) increasing the thickness and rigidity of the SAM structure to induce vertical growth of the dielectric material and prevent rapid growth of the dielectric material on the metal layer.

[0118] In some embodiments, the method 1300 shown in FIG. 13 can be used to perform the DoD process within a single chamber or processing tool. For example, the substrate can be provided within the processing tool (step 1310), the step of forming the SAM structure (step 1320), the step of sequentially exposing the surface of the substrate to a vapor-phase monomer precursor and then a vapor-phase initiator (step 1330), and the step of depositing a dielectric material on the surface of the dielectric layer (step 1340) can each be performed within the same processing tool.

[0119] Throughout this specification, references to "one embodiment" or "an embodiment" mean that the particular features, structures, materials, or characteristics described in connection with the embodiment are included in at least one embodiment of the invention, but do not necessarily mean that they are present in all embodiments. It should be noted that, accordingly, the appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily referring to the same embodiment of the invention. Further, the particular features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments. In other embodiments, various additional layers and / or structures may be included and / or the described features may be omitted.

[0120] As used herein, the term "substrate" means and includes the underlying material or structure on which materials are formed. It will be understood that the substrate can include a single material, multiple layers of different materials, one or more layers having regions of different materials or different structures therein. These materials can include semiconductors, insulators, conductors, or combinations thereof. For example, the substrate can be a semiconductor substrate, a base semiconductor layer on a support structure, a metal electrode, or a semiconductor substrate on which one or more layers, structures, or regions are formed. The substrate can be a conventional silicon substrate or other bulk substrate that includes a layer of semiconductor material. As used herein, the term "bulk substrate" means and includes not only silicon wafers, but also silicon-on-insulator ("SOI") substrates such as silicon-on-sapphire ("SOS") substrates and silicon-on-glass ("SOG") substrates, epitaxial layers of silicon on a base semiconductor substrate, and other semiconductors or optoelectronic materials such as silicon germanium, germanium, gallium arsenide, gallium nitride, and indium phosphide. The substrate may or may not be doped.

[0121] Systems and methods for processing a substrate are described in various embodiments. The substrate can include any material portion or structure of a device, particularly a semiconductor or other electronic device, and can be, for example, a base substrate structure such as a semiconductor substrate or a layer on or covering a base substrate structure such as a thin film. Thus, the substrate is not intended to be limited to any particular base structure, underlying layer, or upper layer that is patterned or unpatterned, but rather is intended to include any such layer or base structure and any combination of layers and / or base structures.

[0122] One of ordinary skill in the art will understand that the various embodiments can be practiced without one or more of the specific details or with other alternative and / or additional methods, materials, or components. In other instances, well-known structures, materials, or details of operations are not illustrated or described so as not to obscure aspects of the various embodiments of the present invention. Similarly, for purposes of explanation, specific numbers, materials, and configurations are disclosed so that the present invention can be understood in detail. Nevertheless, the present invention can be practiced without specific details. Further, it is to be understood that the various embodiments shown in the figures are illustrative representations and are not necessarily drawn to scale.

[0123] Further variations and alternative embodiments of the systems and methods described will be apparent to those skilled in the art from the description herein. Accordingly, it will be recognized that the systems and methods described are not limited to these exemplary configurations. It should be understood that the forms of the systems and methods illustrated and described herein are to be regarded as exemplary embodiments. Various modifications can be made to the implementation. Thus, while the invention has been described herein with reference to specific embodiments, various changes and modifications can be made without departing from the scope of the invention. Accordingly, the specification and drawings are exemplary rather than limiting in nature, and such changes are intended to be included within the scope of the invention. Further, any advantages, effects, or problem solutions described herein with respect to specific embodiments are not intended to be construed as essential, required, or inherent features or elements of any or all of the claims.

Claims

1. A method for region-selective deposition (ASD) of polymer films, wherein the method is: A step of providing a substrate, wherein the substrate has a target material and a non-target material exposed on the surface of the substrate, A step utilizing a sequential pulse-start chemical deposition (spiCVD) process, wherein a polymer film is selectively deposited on the surface of the target material. It has, The step of utilizing the aforementioned spiCVD process is: A step of exposing the surface of the substrate to a gas phase precursor, wherein the gas phase precursor chemically reacts and bonds with the surface of the target material, selectively forming a condensed layer on the surface of the target material while avoiding the formation of condensates on the non-target material. The steps include: selectively forming the condensed layer on the surface of the target material, followed by exposing the surface of the substrate to a gas-phase initiator, wherein the gas-phase initiator reacts with the condensed layer, polymerizes the condensed layer, and selectively deposits the polymer film on the surface of the target material; A method having

2. The method according to claim 1, wherein the surface of the substrate is first exposed to the gas phase precursor for a precursor exposure time, and thereafter the surface of the substrate is subsequently exposed to the gas phase initiator.

3. The method according to claim 2, further comprising the step of controlling the thickness of the polymer film by changing at least one of the precursor exposure time and the vapor pressure of the gas phase precursor.

4. The method according to claim 2, further comprising the step of exposing the surface of the substrate to the gas phase precursor, and subsequently exposing the surface of the substrate to the gas phase initiator, repeated for a predetermined number of cycles, thereby selectively depositing a predetermined thickness of the polymer film onto the surface of the target material without contaminating the non-target material with the polymer.

5. The method according to claim 4, further comprising the step of controlling the amount of the polymer film selectively deposited on the target material each cycle by changing at least one of the precursor exposure time and the vapor pressure of the gas phase precursor.

6. Before exposing the surface of the substrate to the vapor phase precursor, the method further: The steps include determining a selectivity window based on the polymer growth rate achieved cycle by cycle on the target material and the non-target material, The steps include selecting a predetermined number of cycles from the selectivity window necessary to selectively deposit the polymer film of a predetermined thickness onto the surface of the target material without contaminating the non-target material with the polymer, The method according to claim 4, having the following characteristics.

7. The method according to claim 1, wherein the target material is a dielectric material and the non-target material is a metal or a metal oxide material.

8. The step of exposing the surface of the substrate to the vapor phase precursor comprises the step of exposing the surface of the substrate to a monomer precursor. The monomer precursor chemically reacts and bonds with the surface of the dielectric material, selectively forming a monomer condensate layer on the surface of the dielectric material while avoiding the formation of condensates on the metal or metal oxide material. The method according to claim 7, wherein the step of subsequently exposing the surface of the substrate to the vapor-phase initiator polymerizes the monomer condensate layer and selectively deposits the polymer film on the surface of the dielectric material.

9. The step of exposing the surface of the substrate to the vapor phase precursor comprises the step of exposing the surface of the substrate to the dielectric precursor, The dielectric precursor chemically reacts and bonds with the surface of the dielectric material, selectively forming a condensed layer on the surface of the dielectric material while avoiding the formation of condensates on the metal or metal oxide material. The method according to claim 7, wherein the step of subsequently exposing the surface of the substrate to the vapor-phase initiator polymerizes the condensed layer and selectively deposits a dielectric film on the surface of the dielectric material.

10. The method according to claim 1, wherein the target material is a metal or a metal oxide material, and the non-target material is a dielectric material.

11. The method according to claim 10, wherein, prior to the step of exposing the surface of the substrate to the gas phase precursor, the method further comprises the step of forming a self-assembled monolayer (SAM) on the surface of the metal or metal oxide material to form a SAM passivated metal or metal oxide.

12. The step of exposing the surface of the substrate to the vapor phase precursor comprises the step of exposing the surface of the substrate to a monomer precursor, The monomer precursor selectively condenses on the SAM, avoiding the formation of condensates on the dielectric material, and forming a monomer condensate layer on the SAM passivated metal or metal oxide. The method according to claim 11, wherein the step of subsequently exposing the surface of the substrate to the vapor-phase initiator polymerizes the monomer condensate layer and selectively deposits the polymer film on the SAM passivated metal or metal oxide.

13. A method for region-selective deposition (ASD) of polymer films, wherein the method is: A step of providing a substrate, wherein the substrate has a target material and a non-target material exposed on the surface of the substrate, A step utilizing a sequential pulse-start chemical deposition (spiCVD) process, wherein a predetermined thickness of polymer film is selectively deposited on the surface of a target material without contaminating the non-target material with polymer; It has, The step of utilizing the aforementioned spiCVD process is: A step of sequentially exposing the surface of the substrate to a gas phase precursor and a gas phase initiator, wherein the surface of the substrate is first exposed to the gas phase precursor for a precursor exposure time, and thereafter the surface of the substrate is subsequently exposed to the gas phase initiator, the gas phase precursor chemically reacts and bonds with the surface of the target material, selectively forming a condensed layer on the surface of the target material while avoiding the formation of condensates on the non-target material, and the gas phase initiator reacts with the condensed layer, polymerizing the condensed layer and selectively depositing the polymer film on the surface of the target material. The process involves repeatedly exposing the surface of the substrate to the vapor phase precursor and the vapor phase initiator sequentially over a predetermined number of cycles, thereby selectively depositing a predetermined thickness of the polymer film onto the surface of the target material without contaminating the non-target material with the polymer. A method having

14. The method according to claim 13, further comprising the step of controlling the amount of the polymer film selectively deposited on the target material each cycle by changing at least one of the precursor exposure time and the vapor pressure of the gas phase precursor.

15. The method according to claim 14, wherein the amount of the polymer film selectively deposited on the target material in each cycle is less than 2 nm.

16. Prior to the step of exposing the surface of the substrate to the vapor phase precursor, the method further: The steps include determining a selectivity window based on the polymer growth rate achieved cycle by cycle on the target material and the non-target material, From the selectivity window, the step of selecting the predetermined number of cycles necessary to selectively deposit the polymer film of the predetermined thickness onto the surface of the target material without contaminating the non-target material with the polymer; The method according to claim 13, having the following characteristics.

17. The method according to claim 13, wherein the target material is a dielectric material and the non-target material is a metal or a metal oxide material.

18. The step of sequentially exposing the surface of the substrate to the gas phase precursor and the gas phase initiator is, First, the surface of the substrate is exposed to a monomer precursor, wherein the monomer precursor chemically reacts and bonds with the surface of the dielectric material, selectively forming a monomer condensate layer on the surface of the dielectric material while avoiding the formation of condensates on the metal or metal oxide material. The process continues by exposing the surface of the substrate to the vapor-phase initiator to polymerize the monomer condensate layer and selectively depositing the polymer film on the surface of the dielectric material. The method according to claim 17, having the following characteristics.

19. The step of sequentially exposing the surface of the substrate to the gas phase precursor and the gas phase initiator is, First, the surface of the substrate is exposed to a dielectric precursor, wherein the dielectric precursor chemically reacts and bonds with the surface of the dielectric material, selectively forming a condensed layer on the surface of the dielectric material while avoiding the formation of condensates on the metal or metal oxide material. The process continues by exposing the surface of the substrate to the vapor-phase initiator to polymerize the condensed layer and selectively deposit a dielectric film on the surface of the dielectric material. The method according to claim 17, having the following characteristics.

20. The method according to claim 19, wherein the dielectric film is a low-k dielectric film.

21. The method according to claim 13, wherein the target material is a metal or a metal oxide material, and the non-target material is a dielectric material.

22. Before sequentially exposing the surface of the substrate to the vapor phase precursor and the vapor phase initiator, the method further: The method according to claim 21, further comprising the steps of forming a self-assembled monolayer (SAM) assembly on the surface of the metal or metal oxide material, thereby modifying the chemical and / or physical surface properties of the metal or metal oxide material and forming a SAM passivated metal or metal oxide.

23. The step of sequentially exposing the surface of the substrate to the gas phase precursor and the gas phase initiator is, First, the surface of the substrate is exposed to a monomer precursor, wherein the monomer precursor selectively condenses on the SAM assembly, avoiding the formation of condensates on the dielectric material, and forming a monomer condensate layer on the SAM passivated metal or metal oxide. The process continues by exposing the surface of the substrate to the vapor-phase initiator to polymerize the monomer condensate layer and selectively depositing the polymer film on the SAM passivated metal or metal oxide. The method according to claim 22, having the following characteristics.

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