Polymer back film layer for reducing warpage of the substrate

Abstract

The article includes a substrate (e.g., a semiconductor wafer) having a back surface and a back film layer deposited on the back surface of the substrate, the back film layer including a polymer. The back film layer reduces warping or bending of the substrate that may occur when one or more front film layers are deposited on the front surface of the substrate. To form the back film layer, a film composition including a polymer, optionally a wetting agent, and optionally a solvent may be deposited on the back surface of the substrate. Embodiments of the present disclosure are directed to articles and methods including a back film layer including a polymer and deposited on the back surface of a substrate.

Description

Technical Field

[0001] Priority Claim This application claims priority to U.S. Provisional Patent Application No. 63 / 348,824, filed on June 3, 2022, having Attorney Docket No. 1202206-US-F, which is hereby incorporated by reference in its entirety.

[0002] Technical Field The present disclosure relates to a polymer film layer deposited on the back surface of a substrate such as a semiconductor wafer. More particularly, the polymer back film layer can be deposited on the back surface of the substrate as a means of reducing bending or warping that can occur when one or more front film layers are deposited on the front surface of the substrate during a process such as a semiconductor device fabrication operation.

Background Art

[0003] Background Semiconductor device fabrication typically includes deposition and etching operations on the front surface of a wafer. As the deposited layers are built up, they can introduce stress into the wafer, causing the wafer to bend or warp. Conventional backside deposition techniques can be used to deposit a material with a desired film stress on the back surface of the wafer to counteract the bending or warping of the wafer, but conventional backside deposition techniques may require special deposition equipment, which can increase costs and / or complexity.

[0004] Accordingly, there is a need for a new, more cost-effective solution for providing a backside support to a substrate such as a semiconductor wafer as a means of reducing bending or warping during a process such as a semiconductor device fabrication operation.

Summary of the Invention

Means for Solving the Problems

[0005] Summary Embodiments of the present disclosure are directed to articles and methods that include a polymer and a backside film layer deposited on the backside of a substrate.

[0006] According to some embodiments, an article is provided. The article includes a substrate having a backside and a backside film layer deposited on the backside of the substrate, the backside film layer including a polymer.

[0007] According to other embodiments, a method for processing a substrate is provided. The method includes depositing a film composition on the backside of the substrate to form a backside film layer. The film composition includes a polymer, a wetting agent optionally, and a solvent optionally.

[0008] Further features and advantages of these and other embodiments are set forth in the following detailed description, some of which will be readily apparent to those skilled in the art from the detailed description, or will be recognized by practicing the embodiments described in the detailed description and the following claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0009]

Figure 1

[0010]

Figure 2

[0011] DETAILED DESCRIPTION Various embodiments of articles and methods are described in detail below herein that include articles and methods that include a polymer and a backside film layer deposited on the backside of a substrate.

[0012] The present disclosure should not be construed as being limited to the embodiments shown herein. Rather, these embodiments are provided to thoroughly and completely disclose the present disclosure and to fully convey the subject matter to those skilled in the art.

[0013] Definitions

[0014] All technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art, unless otherwise clearly defined. The technical terms used in the disclosure herein are for the purpose of describing particular embodiments only and are not intended to be limiting.

[0015] Unless otherwise clearly described, it is not intended that any method disclosed herein be construed as requiring that its steps be performed in a particular order, nor that any apparatus article shown herein be construed as requiring a particular order or orientation of its individual components.

[0016] Unless otherwise clearly described, it is intended that any composition or mixture disclosed herein may contain, consist essentially of, or consist of the components of the present disclosure.

[0017] As used herein, unless the context clearly indicates otherwise, singular terms are intended to include the plural of that term.

[0018] As used herein, a numerical value is not strictly limited to the recited exact numerical value. Instead, unless otherwise clearly described, each numerical value is intended to mean both the exact numerical value and the "about" numerical value (i.e., the functionally equivalent range surrounding that numerical value) that encompasses it as an embodiment disclosed herein.

[0019] As used herein, the terms "back surface" and "front surface" refer to opposite surfaces of a substrate. The front surface is the first surface of the substrate. For example, if the substrate is a semiconductor wafer, the front surface typically experiences most of the deposition and etching operations during semiconductor fabrication and is the side on which semiconductor devices are fabricated. The back surface is the surface on the second opposite side of the substrate (i.e., the side opposite the front surface). For example, if the substrate is a semiconductor wafer, the back surface typically experiences minimal or no deposition and etching operations during semiconductor fabrication.

[0020] As used herein, the term "bow" or "bowing" refers to the deviation of the central surface point of a free, unclamped wafer from a reference surface established by determination in accordance with ASTM F534-97.

[0021] As used herein, the term "desired film stress" refers to the film stress of a back surface film layer that results in a bow of less than about 100 μm of the substrate on which the back surface film layer is deposited.

[0022] As used herein, the term "film composition" refers to a substance (e.g., a polymer) or a mixture of two or more substances (e.g., a polymer, and at least one of a solvent and a wetting agent, etc.) used to form or develop a back surface film layer on the back surface of a substrate. The film composition may be in the form of a solution such as a liquid solution.

[0023] As used herein, the term "film stress" refers to the stress of a film layer as determined in accordance with ASTM E1426-14 and ASTM E915-16.

[0024] As used herein, the term "glass transition temperature" refers to the temperature (Tg) at which an amorphous substance (or the amorphous region of a semi-crystalline substance) undergoes a glass-liquid transition as determined in accordance with ASTM D3418.

[0025] As used herein, the terms "substrate" and "wafer" are interchangeable. One of ordinary skill in the art will understand that the embodiments described herein may be used before or during any other processing operation of the semiconductor wafer, between any of many stages of semiconductor device and / or integrated circuit fabrication.

[0026] As used herein, the term "tensile modulus" or "Young's modulus" is a mechanical property (E) of a material characterized by its stiffness, and is quantified as the ratio of its tensile stress (σ) to its tensile strain (ε) when subjected to elastic deformation, measured in accordance with ASTM D882-18.

[0027] As used herein, the term "warp" or "warpage" refers to the difference between the maximum and minimum distances of the central surface of a free, unclamped wafer from a reference plane, as measured in accordance with ASTM F1390.

[0028] Usefulness

[0029] As discussed above herein, semiconductor fabrication operations include the formation of various structures, many of which may be two-dimensional. As semiconductor device dimensions are scaled down and devices are made smaller, the density of features across the semiconductor substrate increases, and layers of materials are etched and deposited in various ways, including three dimensions. For example, 3D-NAND is one technology that is becoming increasingly common in various applications due to its lower cost, increased memory density, and high reliability compared to other technologies such as 2D-NAND.

[0030] In the fabrication of 3D-NAND memory devices, multiple stacked films with thick high-stress deposits are applied, which can cause significant wafer warping and lead to issues of in-plane distortion (IPD) and focus shift in the argon fluoride (ArF) photolithography process. Currently, the only solution is backside deposition by plasma-enhanced chemical vapor deposition (PECVD). However, this technique disadvantageously requires special deposition equipment and increases the cost burden on integrated circuit (IC) fabrication plants.

[0031] The articles and methods disclosed herein mitigate the aforementioned problems.

[0032] The article disclosed herein includes a substrate having a backside and a backside film layer deposited on the backside of the substrate, the backside film layer including a polymer. To form the backside film layer, a film composition including a polymer, optionally a wetting agent, and optionally a solvent may be deposited on the backside of the substrate.

[0033] A method for processing a substrate as disclosed herein includes depositing a film composition on the backside of the substrate to form a backside film layer. The film composition includes a polymer, optionally a wetting agent, and optionally a solvent.

[0034] The film composition as disclosed herein is deposited without the need for special deposition techniques or equipment and can achieve a desired film stress in the resulting backside film layer to reduce the warping of the substrate during processes such as semiconductor device and / or integrated circuit fabrication operations.

[0035] Article

[0036] The article disclosed in this specification includes a substrate having a back surface and a back film layer deposited on the back surface of the substrate, the back film layer containing a polymer. To form the back film layer, a film composition containing a polymer, optionally a wetting agent, and optionally a solvent may be deposited on the back surface of the substrate.

[0037] In an embodiment, the article may be a partially or fully fabricated semiconductor device, such as a partially or fully fabricated integrated circuit.

[0038] Substrate

[0039] Referring to FIG. 1, the article 100 disclosed in this specification includes a substrate 102 having a back surface 104 and a front surface 106 opposite the back surface 104.

[0040] In an embodiment, the substrate 102 may include a semiconductor material. In an embodiment, the semiconductor material can be selected from any known semiconductor material. In an embodiment, the semiconductor material can be selected from at least one of silicon (Si), silicon carbide (SiC), gallium arsenide (GaAs), gallium nitride (GaN), and germanium (Ge).

[0041] In an embodiment, the substrate may be substantially circular and may have a diameter of 200 mm, 300 mm, or 450 mm.

[0042] Back film layer

[0043] The back film layer 108 is deposited on the back surface 104 of the substrate 102 to counteract the stress caused by the layer deposited on the front surface 106 of the substrate 102 and the resulting bend or warp.

[0044] To form the backside film layer 108, the film composition may be deposited on the backside of the substrate. As described elsewhere herein, the film composition may include, consist essentially of, or consist of a polymer, a wetting agent if necessary, and a solvent if necessary. In some embodiments, the solvent in the film composition may be removed during processing (e.g., by drying) to facilitate the formation of the backside film layer 108. Thus, the backside film layer 108 may include a polymer, a wetting agent if necessary, and a solvent if necessary. In embodiments, after the drying process, no solvent may be present in the backside film layer 108 or it may be present in the backside film layer 108 below the minimum allowable residual solvent amount. For example, in embodiments, the minimum allowable residual solvent amount may be less than or equal to about 0.6 wt% relative to the total weight of the backside film layer (i.e., the film composition after drying).

[0045] The optimum thickness of the backside film layer 108 may depend on the specific formulation of the film composition used to form the backside film layer 108 and / or the stress forces induced by the deposition on the front side 106 of the substrate 102. The backside film layer 108 may be deposited to a thickness such that the wafer bow is negligible (e.g., a bow of less than about 100 μm). The total thickness of the backside film layer 108 may be achieved by depositing a single layer (e.g., up to 20 μm) or multiple laminations (e.g., up to 50 μm) to form the backside film layer 108.

[0046] For example, in an embodiment, the back film layer 108 may have a thickness less than 50 μm or equal thereto, less than 30 μm or equal thereto, less than 20 μm or equal thereto, less than 10 μm or equal thereto, less than 8 μm or equal thereto, less than 5 μm or equal thereto, less than 3 μm or equal thereto, or less than 1 μm or equal thereto, and greater than 0.5 μm or equal thereto, or greater than 0.7 μm or equal thereto. Thus, in an embodiment, the back film layer 108 may have a thickness of 0.5 μm to 50 μm, 0.5 μm to 30 μm, 0.5 μm to 20 μm, 0.5 μm to 10 μm, 0.5 μm to 8 μm, 0.5 μm to 5 μm, 0.5 μm to 2 μm, 0.5 μm to 1 μm, 0.7 μm to 50 μm, 0.7 μm to 30 μm, 0.7 μm to 20 μm, 0.7 μm to 10 μm, 0.7 μm to 8 μm, 0.7 μm to 5 μm, 0.7 μm to 3 μm, 0.7 μm to 1 μm, or any and all sub-ranges formed from any of these endpoints.

[0047] As described herein, the back film layer 108 should have a tensile modulus of elasticity that resists bending or warping caused by depositing a layer on the front surface 106 of the substrate 102. For example, in an embodiment, the back film layer 108 may have a tensile modulus of elasticity greater than 1 GPa, greater than 2 GPa, or greater than 3 GPa. In an embodiment, the back film layer 108 may have a tensile modulus of elasticity of about 1 GPa to about 2.5 GPa, or about 1 GPa to about 2.4 GPa, or about 1 to about 2.3 GPa.

[0048] In an embodiment, the back film layer 108 may include a blend of polyamide-imide (PAI) and polyimide (PI) having a weight ratio of about 19:1 to about 4:1 (e.g., about 15:1) and having a glass transition temperature of about 230 °C to about 295 °C (e.g., about 291 °C).

[0049] Film composition

[0050] To form the back film layer, the film composition may be deposited on the back surface of the substrate.

[0051] In an embodiment, the film composition may include a polymer, a wetting agent if necessary, and a solvent if necessary. In an embodiment, the film composition may include a polymer and at least one of a wetting agent and a solvent. In an embodiment, the film composition may include a polymer, a solvent, and a wetting agent if necessary, and can be used in the form of a solution such as a liquid solution.

[0052] In an embodiment, the film composition may have a viscosity of about 100 cP to about 27,000 cP when measured at 25°C. However, the viscosity can be adjusted so as not to exceed the maximum viscosity that can be handled by a conventional spin coater device, which can be about 8000 cP in an embodiment when measured at 25°C. Thus, in an embodiment, the film composition may have a viscosity of about 100 cP to about 8000 cP when measured at 25°C. With a viscosity in this range, it is possible to achieve a good coating of the film composition onto the back surface of the substrate using a conventional spin coater device.

[0053] Polymer

[0054] The back surface film layer 108 includes a polymer that enables the realization of a desired film stress and enables the deposition of the film composition to form the back surface film layer 108 without the need for a special deposition device. For example, a film composition containing a polymer can be deposited using a conventional spin coater device and a baking device in a photolithography process. The polymer also enables the relatively easy removal of the back surface film layer 108 after further processing using a conventional spin coater device and a sufficient amount of solvent.

[0055] In some embodiments, the polymer may include a single type of polymer. In other embodiments, the polymer may include a blend of polymers or two or more different types of polymers.

[0056] In embodiments, the polymer can be selected from at least one of polybenzimidazole (PBI), polyetherimide (PEI), polyamide-imide (PAI), polyimide (PI), polysulfone (PSU), polyphenylsulfone (PPSU), polyethersulfone (PES), and polybenzoxazole (PBO). For example, in some embodiments, particularly suitable polymers include at least one of polyamide-imide (PAI), polyimide (PI), polyphenylsulfone (PPSU), and polyethersulfone (PES).

[0057] In embodiments, the polymer can be a blend of polyimide (PI) and polybenzimidazole (PBI); or a blend of polysulfone (PSU) and polybenzoxazole (PBO); or a blend of polysulfone (PSU) and polyimide (PI); or a blend of polyamide-imide (PAI) and polyimide (PI); or a blend of polyimide (PI) and at least one of polyamide-imide (PAI), polyimide (PI), and polyetherimide (PEI); or a blend of polysulfone (PSU) and at least one of polyimide (PI), polyetherimide (PEI), and polyamide-imide (PAI); or a blend of polyimide (PI), polyamide-imide (PAI), and polyetherimide (PEI); or a blend of polyamide-imide (PAI), polyimide (PI), and polyethersulfone (PES). For example, in some embodiments, particularly suitable polymers include a two-component blend of polyamide-imide (PAI) and polyimide (PI); and a three-component blend of polyamide-imide (PAI), polyimide (PI), and polyethersulfone (PES).

[0058] In embodiments where the polymer comprises two or more different polymers, the polymers can be used in a blend in a suitable weight ratio.

[0059] In embodiments where the polymer comprises a two-component blend of a first polymer and a second polymer, the weight ratio of the first polymer to the second polymer can be, for example, 95:5, 85:15, 80:20, 60:40, 50:50, and 40:60.

[0060] For example, in some embodiments where the polymer comprises a two-component blend of polyamide-imide (PAI) and polyimide (PI), the weight ratio of PAI to PI can be from 499:1 to 1:4, for example, 499:1, 249:1, 166:1, 124:1, 99:1, 19:1, 15:1, 17:3, 4:1, 3:2, 1:1, 2:3, or 1:4.

[0061] In embodiments where the polymer comprises a three-component blend of a first polymer, a second polymer, and a third polymer, the weight ratio of the first polymer to the second polymer to the third polymer can be, for example, 60:15:25, 40:10:50, and 20:5:75.

[0062] For example, in some embodiments where the polymer comprises a three-component blend of polyamide-imide (PAI), polyimide (PI), and polyethersulfone (PES), the weight ratio of PAI to PI to PES can be 12:3:5, 4:1:5, or 4:1:15.

[0063] In embodiments where a solvent is included in the film composition, the amount of the polymer in the film composition may be greater than or equal to 1 wt%, greater than or equal to 2 wt%, greater than or equal to 5 wt%, or greater than or equal to 10 wt% with respect to the total weight of the film composition, and may be less than 50 wt%, less than 45 wt%, or less than 40 wt%. Thus, in embodiments, the amount of the polymer in the film composition can be 1 wt% to 50 wt%, 2 wt% to 50 wt%, 5 wt% to 45 wt%, 10 wt% to 40 wt%, or any and all subranges formed from any of these endpoints.

[0064] In embodiments where the solvent is not included in the film composition, the amount of polymer in the film composition can be 99 wt% to 100 wt%, 99.5 wt% to 100 wt%, 99.8 wt% to 100 wt%, or any and all subranges formed from any of these endpoints, based on the total weight of the film composition.

[0065] In embodiments, the polymer can have a glass transition temperature greater than or equal to 200 °C, greater than or equal to 240 °C, or greater than or equal to 260 °C, and less than or equal to 300 °C, or less than or equal to 280 °C. Thus, in embodiments, the polymer can have a glass transition temperature in the range of 200 °C to 300 °C, 200 °C to 280 °C, 240 °C to 300 °C, 240 °C to 280 °C, 260 °C to 300 °C, 260 °C to 280 °C, or any and all subranges formed from any of these endpoints.

[0066] Suitable commercially available embodiments of polyamide-imide are available under the TORLON brand from Solvay, e.g., grades 4275 and Al-10; polyimide is available under the MATRAMID brand from Huntsman Corporation, e.g., grade 5318, the DURATRON brand from Mitsubishi Chemical Advanced Materials, e.g., grade D7000, and the NOVACLEAR brand from NeXolve Corporation; polyphenylsulfone is available under the RADEL brand from Solvay, e.g., grades R-5000 and R-5900; polyethersulfone is available under the VERADEL brand from Solvay, e.g., grade A-201 NT, and the ULTRASON brand from BASF, e.g., grade E.

[0067] For example, among the commercially available embodiments of the polymer, particularly suitable ones include MATRAMID 5318 polyimide manufactured by Huntsman, TORLON Al-10 polyamide-imide manufactured by Solvay, and ULTRASON E polyethersulfone manufactured by BASF.

[0068] Solvent

[0069] In an embodiment, the film composition may further include a solvent that dissolves the polymer. Thus, in an embodiment, when the film composition is deposited on the back surface of the substrate to form the back surface film layer 108, it can be used in the form of a solution such as a liquid solution.

[0070] In an embodiment, the solvent can be selected from the group consisting of at least one of amide, imide, imidazole, dioxane, dialkylaminooxopentanoate, valerolacetone, oxopentanoate, dialkylacetamide, and N-alkylpyrrolidone. In an embodiment, the dialkylacetamide may include dimethylacetamide (DMAC). In an embodiment, the N-alkylpyrrolidone may include N-methylpyrrolidone (NMP). In an embodiment, the dialkylaminooxopentanoate (DAOP) may include 5-(dialkylamino)-2-methyl-5-oxopentanoate). A particularly suitable commercially available embodiment of dialkylaminooxopentanoate (DAOP) is available under the RHODIASOLV brand manufactured by Solvay, for example, POLARCLEAN.

[0071] Particularly suitable embodiments of the solvent include N-alkylpyrrolidone, for example, NMP. Advantageously, when NMP is used as the solvent, it contributes to achieving the desired viscosity of the film composition, which in turn contributes to achieving a good coating of the film composition on the back surface of the substrate using a conventional spin coater device. As described elsewhere herein, in an embodiment, the film composition may have a viscosity of about 100 cP to about 27000 cP, or about 100 cP to about 8000 cP when measured at 25°C.

[0072] In contrast, for example, when DMAC is used as a solvent, it can contribute to a lower viscosity of the film composition than desired. Further, for example, when a DAOP such as POLARCLEAN is used as a solvent, it can contribute to a higher viscosity of the film composition than desired.

[0073] In embodiments, the amount of solvent in the film composition may be greater than or equal to 50 wt%, greater than or equal to 55 wt%, or greater than or equal to 60 wt% relative to the total amount of the film composition, and less than 99 wt%, less than 95 wt%, or less than 90 wt%. Thus, in embodiments, the amount of solvent in the film composition may be 50 wt% - 99 wt%, 55 wt% - 95 wt%, 60 wt% - 90 wt%, or any and all subranges formed from any of these endpoints relative to the total amount of the film composition.

[0074] In embodiments, the solvent in the film composition may be removed during processing (e.g., by drying) to form the back film layer 108. The solvent remaining in the back film layer after drying may be referred to as residual solvent.

[0075] For example, in embodiments, the drying process may be carried out including the following steps: (i) soft baking to achieve slow evaporation of the solvent and promote film formation (e.g., at about 180 °C for about 5 minutes); (ii) hard baking at the boiling point or above the boiling point of the solvent to remove residual solvent from the film (e.g., at about 200 °C for about 15 minutes); and (iii) curing to achieve a minimum amount of residual solvent and a target curing level (e.g., at about 250 °C for about 15 minutes).

[0076] In an embodiment, the minimum allowable amount of residual solvent may be less than about 0.6 wt% or equal to about 0.6 wt% based on the total weight of the back film layer (i.e., the dried film composition).

[0077] Wetting agent

[0078] In an embodiment, the film composition may further include a wetting agent to improve the wettability of the film composition for deposition (e.g., coating as a liquid solution) on the back surface of the substrate.

[0079] In an embodiment, the amount of the wetting agent in the film composition may be greater than or equal to 0.1 wt%, greater than or equal to 0.15 wt%, or greater than or equal to 0.18 wt% based on the total amount of the film composition, and less than or equal to 1 wt%, less than or equal to 0.5 wt%, or less than or equal to 0.25 wt%. Thus, in an embodiment, the amount of the solvent in the film composition may be from 0.01 wt% to 1 wt%, from 0.15 wt% to 0.5 wt%, from 0.18 wt% to 0.25 wt%, or any and all sub-ranges formed from any of these endpoints. For example, in an embodiment, the amount of the wetting agent may be 0.2 wt% based on the total amount of the film composition.

[0080] Suitable wetting agents can include conventional or commercially available wetting agents, including dyes having wetting properties such as anthraquinone dyes.

[0081] For example, a particularly suitable embodiment of the wetting agent can include MACROLEX Green 5B available from Lanxess.

[0082] Non-limiting exemplary embodiments

[0083] In an embodiment, the film composition may include 0.5 wt% to 27 wt% of a polymer selected from polybenzimidazole and 73 wt% to 95 wt% of a solvent selected from at least one of dialkylacetamide, N-methylpyrrolidone, and dialkylformaldehyde, based on the total weight of the film composition.

[0084] In an embodiment, the film composition may include 2 wt% to 50 wt% of a polymer including a blend of polyimide and at least one other polymer selected from polyamide-imide, polyimide, and polyetherimide in a weight ratio of 1:1 to 1:10, based on the total weight of the film composition.

[0085] In an embodiment, the film composition may include 2 wt% to 12 wt% of a polymer including a blend of polysulfone and at least one other polymer selected from polyimide, polyetherimide, and polyamide-imide in a weight ratio of 1:3 to 3:1, and 50 wt% to 95 wt% of a solvent selected from at least one of dialkylaminooxopentanoate, valeroacetone, oxopentanoate, dialkylacetamide, and N-alkylpyrrolidone, based on the total weight of the film composition.

[0086] In an embodiment, the film composition may include 2 wt% to 30 wt% of a polymer including a blend of polysulfone (or a similar polymer) and polyimide (or a similar polymer) in a weight ratio of 3:1 to 1:3, and 70 wt% to 98 wt% of a solvent selected from at least one of dialkylaminooxopentanoate, valeroacetone, oxopentanoate, dialkylacetamide, and N-alkylpyrrolidone, based on the total weight of the film composition.

[0087] In an embodiment, the film composition may include 5 wt% to 20 wt% of a polymer selected from polysulfone and 80 wt% to 95 wt% of a solvent selected from at least one of dialkylaminooxopentanoate, valeroacetone, dialkylacetamide, and N-methylpyrrolidone, based on the total weight of the film composition.

[0088] In an embodiment, the film composition may include 20 wt% to 99.8 wt% of a polymer selected from polyamide-imide and 0.2 to 80 wt% of polyimide, based on the total weight of the film composition. The film may also contain 0.02 wt% to 0.6 wt% of volatile substances. The volatile substances may include residual solvents, bound moisture, or volatile organic substances generated during the curing reaction of the polymer.

[0089] In an embodiment, a film composition derived from a 15 wt / vol% to 50 wt / vol% polymer solution may include a polymer containing a blend of polyamide-imide and polyimide in a weight ratio of 1:4 to 499:1, based on the total weight of the film composition.

[0090] In an embodiment, the film composition may include 2 wt% to 20 wt% of a polymer selected from at least one of polyimide, polyamide-imide, and polyetherimide, based on the total weight of the film composition.

[0091] Front film layer

[0092] In an embodiment, at least one front film layer 110 may be deposited on the front surface 106 of the substrate 102. For example, in an embodiment, the article 100 may be a partially fabricated integrated circuit.

[0093] In an embodiment, at least one front film layer 110 may include any number of layers and thicknesses. For example, at least one front film layer 110 may include 32 to 72 layers and may have a total thickness of about 2 μm to about 4 μm. Further, due to advancements in the art, it may be possible to increase the number of layers stacked as the front film layer 110 of the substrate 102, and thus it should be understood that the requirements for the backside reduction process using the back film layer 108 as disclosed herein may also increase. In an embodiment, the stress induced by the substrate 102 by at least one front film layer 110 can be from about -500 MPa to about +500 MPa and can result in a bend (for a 300 mm wafer) that can be from about 200 μm to about 400 μm. One skilled in the art will recognize that the number of layers of at least one front film layer 110 may depend on the application of the 3D-NAND memory device in which it is incorporated.

[0094] In an embodiment, at least one front film layer 110 may include silicon oxide, silicon nitride, polysilicon, tungsten, titanium nitride, or a combination thereof. In an embodiment, at least one front film layer 110 may include alternating layers of oxides and nitrides (e.g., silicon oxide / silicon nitride / silicon oxide / silicon nitride, etc.). In other embodiments, at least one front film layer 110 may include alternating layers of oxides and tungsten (e.g., silicon oxide / tungsten / silicon oxide / tungsten, etc.). At least one front film layer 110 may be deposited by chemical vapor deposition techniques such as plasma enhanced chemical vapor deposition (PECVD), low pressure chemical vapor deposition (LPCVD), metal organic chemical vapor deposition (MOCVD), atomic layer deposition (ALD), plasma enhanced atomic layer deposition (PEALD), or by direct metal deposition (DMD).

[0095] Method for processing

[0096] Referring to FIG. 2, a method for processing a substrate is shown at 200. Returning to FIG. 1, the method includes a step 202 of depositing a film composition on a back surface 104 of a substrate 102 to form a back surface film layer 108. The film composition can be a film composition according to any of the embodiments described herein.

[0097] In an embodiment, the depositing step 202 includes spin coating, e.g., spin coating techniques described in U.S. Patent Nos. 5,238,878; 5,780,105; and 6,436,851, which are hereby incorporated by reference in their entirety. For example, conventional equipment used in conventional processing such as a photolithography process, e.g., a spin-on coating apparatus, can be used.

[0098] Method 200 of FIG. 2 optionally includes a step 204 of drying or curing the film composition. In embodiments, the drying or curing step is at a temperature greater than or equal to 90° C., or greater than or equal to 120° C., or greater than or equal to 150° C., or greater than or equal to 180° C., and less than 250° C., or less than 200° C., or less than 170° C., or less than 140° C., and for a time greater than or equal to 30 seconds, or greater than or equal to 1 minute, or greater than or equal to 2 minutes, and less than 35 minutes, or less than 20 minutes, or less than 10 minutes, or less than 5 minutes, or less than 180 seconds, and may include heating the film composition over that time. For example, in embodiments, the drying or curing process may be carried out including the following steps: (i) a step of soft baking to achieve slow evaporation of the solvent and promote film formation (e.g., at about 180° C. for about 5 minutes); (ii) a step of hard baking at or above the boiling point of the solvent to remove residual solvent from the film (e.g., at about 200° C. for about 15 minutes); and (iii) a step of curing to achieve a minimum amount of residual solvent and a target curing level (e.g., at about 250° C. for about 15 minutes). In embodiments, the drying or curing step may result in a back film layer 108 having sufficient insolubility to prevent removal of the film layer by the solvent during post-processing.

[0099] Returning to FIG. 1, method 200 of FIG. 2 further optionally includes a step 206 of depositing a front film layer 110 on the front surface 106 of the substrate 102. The front film layer and its deposition may be in accordance with any of the embodiments described herein. In embodiments, the step 206 of depositing the front film layer 110 on the front surface 106 of the substrate 102 may be performed before the step 202 of depositing the film composition on the back surface 104 of the substrate 102.

[0100] Method 200 of FIG. 2 further optionally includes step 208 of removing the back film layer 108 from the substrate 102. For example, in an embodiment, the back film layer 108 can be removed by a conventional process such as wet chemical etching. Suitable cleaning agents for removing the back film layer 108 from the substrate 102 include N-alkyl pyrrolidone, for example, N-methyl pyrrolidone (NMP).

[0101] All documents cited herein are hereby incorporated by reference in their entirety, unless otherwise specified. The citation of any document should not be construed as an admission that it is prior art with respect to any invention disclosed or claimed herein. In the event of any conflict between the meaning or definition of any term in this document and the meaning or definition of the same term in a document incorporated by reference, the meaning or definition assigned to that term in this document shall prevail.

[0102] It is apparent that modifications and changes can be made without departing from the scope of the appended claims of the present disclosure. Although some aspects of the present disclosure are identified herein as preferred or particularly advantageous, it is contemplated that the present disclosure is not necessarily limited to these aspects.

[0103] What is claimed is as follows.

Claims

1. a substrate having a back surface; a back film layer deposited on the back surface of the substrate, the back film layer containing a polymer An article comprising:

2. The article according to claim 1, wherein the substrate has a front surface and further comprises at least one front film layer deposited on the front surface of the substrate.

3. The article according to any one of the preceding claims, wherein the substrate is a semiconductor wafer containing at least one of silicon, silicon carbide, gallium arsenide, gallium nitride, and germanium, and the article is a partially or fully fabricated integrated circuit.

4. The article according to any one of the preceding claims, wherein the polymer contains at least one of polybenzimidazole (PBI), polyetherimide (PEI), polyamide-imide (PAI), polyimide (PI), polysulfone (PSU), polyphenylsulfone (PPSU), polyethersulfone (PES), and polybenzoxazole (PBO).

5. The article according to any one of the preceding claims, wherein the polymer contains at least one of polyamide-imide (PAI), polyimide (PI), polyphenylsulfone (PPSU), and polyethersulfone (PES).

6. The article according to any one of the preceding claims, wherein the polymer contains any one of (i) polyethersulfone (PES); or (ii) a blend of polyamide-imide (PAI) and polyimide (PI); or (iii) a blend of polyamide-imide (PAI), polyimide (PI), and polyethersulfone (PES).

7. The article according to any one of the preceding claims, wherein the back film layer is deposited as a film composition containing the polymer, a wetting agent as required, and a solvent as required, the solvent containing at least one of amide, imide, imidazole, dioxane, dialkylaminooxopentanoate, valeroacetone, oxopentanoate, dialkylacetamide, and N-alkylpyrrolidone.

8. The article according to any one of the preceding claims, wherein the back film layer is deposited as a film composition comprising the polymer, a wetting agent if necessary, and a solvent, the solvent comprises N-alkylpyrrolidone, and the film composition has a viscosity of about 100 cP to about 8000 cP when measured at 25°C.

9. The article according to any one of the preceding claims, wherein the back film layer has a thickness of about 0.5 μm to about 50 μm.

10. The article according to any one of the preceding claims, wherein the back film layer has a tensile modulus of about 1 GPa to about 2.3 GPa.

11. The article according to any one of the preceding claims, wherein the back film layer has a glass transition temperature of about 230°C to about 295°C and comprises a blend of polyamide-imide (PAI) and polyimide (PI) in a weight ratio of about 19:1 to about 4:

1.

12. A method for processing a substrate, the method comprising: depositing a film composition on the back surface of the substrate and, if necessary, drying and / or curing the film composition to form a back film layer, the film composition comprising a polymer, a wetting agent if necessary, and a solvent if necessary.

13. The method according to claim 12, wherein the substrate has a front surface and further comprises at least one front film layer deposited on the front surface of the substrate.

14. The method according to any one of claims 12 to 13, wherein the substrate is a semiconductor wafer comprising at least one of silicon, silicon carbide, gallium arsenide, gallium nitride, and germanium, and the substrate is processed to comprise a partially or fully fabricated integrated circuit.

15. The method according to any one of claims 12 to 14, wherein the polymer comprises at least one of polybenzimidazole (PBI), polyetherimide (PEI), polyamide-imide (PAI), polyimide (PI), polysulfone (PSU), polyphenylsulfone (PPSU), polyethersulfone (PES), and polybenzoxazole (PBO).

16. The method according to any one of claims 12 to 15, wherein the polymer comprises at least one of polyamide-imide (PAI), polyimide (PI), polyphenylsulfone (PPSU), and polyethersulfone (PES).

17. The method according to any one of claims 12 to 16, wherein the polymer comprises any one of (i) polyethersulfone (PES); or (ii) a blend of polyamide-imide (PAI) and polyimide (PI); or (iii) a blend of polyamide-imide (PAI), polyimide (PI) and polyethersulfone (PES).

18. The method according to any one of claims 12 to 17, wherein the solvent comprises at least one of amide, imide, imidazole, dioxane, dialkylaminooxopentanoate, valeroacetone, oxopentanoate, dialkylacetamide, and N-alkylpyrrolidone.

19. The method according to any one of claims 12 to 18, wherein the solvent comprises N-alkylpyrrolidone, and the film composition has a viscosity of about 100 cP to about 8000 cP when measured at 25°C.

20. The method according to any one of claims 12 to 19, wherein the back film layer has a thickness of about 0.5 μm to about 50 μm.

21. The method according to any one of claims 12 to 20, wherein the back film layer has a tensile modulus of about 1 GPa to about 2.3 GPa.

22. The method according to any one of claims 12 to 21, wherein the depositing step comprises spin coating.

23. The method according to any one of claims 12 to 22, further comprising a step of drying and / or curing the film composition to form the back film layer.

24. The method according to claim 23, wherein the back film layer comprises a residual solvent of less than about 0.6 wt% or equal to about 0.6 wt% based on the total weight of the back film layer.

25. The method according to any one of claims 12 to 24, further comprising a step of removing the back film layer from the back surface of the substrate, and the removing step comprises using a cleaning agent containing N-methylpyrrolidone (NMP).

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