Silicon nitride etching compositions and methods

Abstract

Compositions and methods are provided for wet etching surfaces of microelectronic device substrates, including surfaces containing silicon nitride, silicon oxide, and polysilicon. The method of the present invention includes a passivation step and a silicon nitride etching step, as described in more detail below. It has been found that the combination of the two steps significantly improves the selectivity of the silicon nitride etching operation in the presence of polysilicon.

Description

[Technical field]

[0001] The present invention relates to compositions and methods for selectively etching silicon nitride in the presence of silicon oxide and polysilicon.

[0002] Priority claim This disclosure claims priority to U.S. Provisional Patent No. 63 / 341,801, filed May 13, 2022. This priority document is incorporated herein by reference for all purposes. [Background technology]

[0003] In the microelectronics industry, there is a continuing demand for improved device performance and smaller device dimensions and smaller device feature dimensions, which provide the dual benefits of higher density of device features and higher device speeds.

[0004] Shrinking feature and device dimensions necessitate finding new ways to improve the multi-step process steps for manufacturing microelectronic devices. The removal of silicon nitride (Si) is common in the methods for fabricating many types of microelectronic devices. 3 N 4 ) is usually a thin layer of silane (SiH 4 ) and ammonia (NH 3 ) by chemical vapor deposition and can be useful in microelectronic devices as water and sodium barriers. Patterned silicon nitride layers are also used as masks for spatially selective silicon oxide growth. After application, all or part of these silicon nitride materials may need to be removed, which is typically done by etching.

[0005] The removal of silicon nitride from a substrate by etching is advantageously performed in a manner that does not damage or destroy other exposed or covered features of the microelectronic device. Often, the process of removing silicon nitride is performed in a manner that preferentially removes silicon nitride relative to other materials, such as silicon oxide, that are also present on the surface of the microelectronic device substrate. According to various commercial methods, silicon nitride is removed by etching the substrate surface in an elevated temperature, e.g., a bath having a temperature in the range of 150° C. to 180° C., with concentrated phosphoric acid (H 3 PO 4 Silicon nitride is removed from microelectronic device surfaces by a wet etching process that involves exposing the silicon nitride to aqueous phosphoric acid (H 3 PO 4 ), typically about 85 weight percent phosphoric acid and 15 weight percent water have been used. Using fresh hot phosphoric acid, a typical Si 3 N 4 :SiO 2 The selectivity can be approximately 40:1.

[0006] In additional device structures, in addition to silicon oxide, exposed surfaces of polysilicon may also be present, further complicating the desired selective silicon nitride etching process. Thus, there is a need for compositions and methods useful for preferentially etching silicon nitride in the presence of silicon oxide and polysilicon surfaces. Summary of the Invention

[0007] In summary, the present invention relates to compositions and methods for wet etching the surface of a microelectronic device substrate, including surfaces that include silicon nitride, silicon oxide, and polysilicon. Optionally, other materials are present on the substrate, such as conductive, semiconductive, or insulating materials useful for microelectronic devices, or processing materials useful for the fabrication of microelectronic devices. Materials such as metal silicides may also be present, but are often not exposed, except where defects such as cracks or lithographic misalignment exist. The method of the present invention includes a passivation step and a silicon nitride etching step, as described in more detail below. It has been found that the combination of the two steps significantly improves the selectivity of the silicon nitride etching operation in the presence of polysilicon and silicon oxide. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a process flow diagram showing a structure having polysilicon at the bottom of the via, but also including silicon oxide and silicon nitride surfaces. The first step of surface oxide removal is typically performed with dilute hydrogen fluoride. Without the passivation step of the present invention, the exposed polysilicon would typically be undesirably etched and roughened during the silicon nitride etch step. [Diagram 2] FIG. 1 illustrates the results of the method of the present invention, where a microelectronic device substrate having polysilicon, silicon oxide and silicon nitride surfaces is subjected to the process of the present invention, and etching and roughening of the exposed polysilicon surfaces is significantly reduced. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term "or" is generally used in its sense including "and / or" unless the content clearly dictates otherwise.

[0010] The term "about" generally refers to a range of numbers that are considered equivalent to the stated value (e.g., having the same function or result). In many cases, the term "about" may include numbers that are rounded to the nearest significant figure.

[0011] Numerical ranges expressed using endpoints include all numbers subsumed within that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5). a. about 20 to about 80 weight percent sulfuric acid; b. about 20 to about 80 weight percent water; c. about 0.01 to about 0.4 weight percent sulfurous acid; d. about 0.1 to about 10 weight percent nitric acid, and, optionally, e. about 0.001 to about 0.1 weight percent formic acid; The present invention provides a composition comprising the reaction product of:

[0012] Thus, in these compositions, the starting material components include a. through d., and optionally e., with the total weight percent of such components being 100 weight percent. In one embodiment, the composition comprises: a. about 59 to about 65 weight percent sulfuric acid; b. about 36 to about 41 weight percent water; c. about 0.01 to about 0.3 weight percent sulfurous acid; d. about 0.1 to about 0.04 weight percent nitric acid, and, optionally, e. about 0.005 to about 0.1 weight percent formic acid; It is the reaction product of:

[0013] In a further embodiment of this aspect, nitric acid is utilized in an amount of about 0.1 to about 0.25 weight percent, based on the total weight of the composition.

[0014] As mentioned above, this first aspect is a composition that is the reaction product of the listed starting materials. In solution, the primary oxidizing agent is nitric acid. It is believed that sulfurous acid reduces a portion of the nitric acid to provide more active oxidizing species such as nitrogen dioxide and nitrous acid in situ.

[0015] In certain embodiments, the compositions also utilize formic acid, which aids in extending bath life. In compositions of this aspect, the formic acid is subject to partial oxidation to performic acid.

[0016] The composition of this first aspect is useful as a passivation composition in the selective etching of silicon nitride on microelectronic substrates. The composition has been found to be effective in passivating surfaces other than silicon nitride, particularly polysilicon and silicon oxide surfaces that are also commonly present on microelectronic device substrates when the desired silicon nitride etching step is performed.

[0017] In selective etching of silicon nitride, a first step generally involves removing residual surface oxide material on the silicon nitride surface, usually with dilute HF, and then treating the microelectronic device substrate with a composition of this first aspect, followed by rinsing and then treatment with a silicon nitride etching composition. Thus, in a second aspect, the present invention provides a method for selectively etching silicon nitride on a microelectronic device substrate, the substrate comprising a surface comprising silicon nitride, a surface comprising silicon oxide, and a surface comprising polysilicon, the method comprising: a. exposing a microelectronic device substrate including silicon nitride, silicon oxide, and polysilicon surfaces to a composition including nitrous acid; Next, b. rinsing the substrate with a liquid solution comprising water; c. exposing the substrate to a composition effective to etch silicon nitride under conditions effective to etch silicon nitride.

[0018] In one embodiment, the invention provides a method for selectively etching silicon nitride on a microelectronic device substrate, the substrate comprising a surface comprising silicon nitride, a surface comprising silicon oxide, and a surface comprising polysilicon, the method comprising: a. a microelectronic device substrate comprising a silicon nitride, silicon oxide and polysilicon surface, i. about 20 to about 80 weight percent sulfuric acid; ii. about 20 to about 80 weight percent water; iii. about 0.01 to about 0.4 weight percent sulfurous acid; iv. about 0.1 to about 10 weight percent nitric acid, and, optionally, v. about 0.001 to about 0.1 weight percent formic acid; to a composition comprising the reaction product of Next, b. rinsing the substrate with a liquid solution comprising water; c. exposing the substrate to a composition effective to etch silicon nitride under conditions effective to etch silicon nitride.

[0019] In this method, compositions effective for etching silicon nitride (i.e., step c.) include compositions known in the art to be effective for etching silicon nitride, such as a mixture of phosphoric acid and water. In this method, an initial passivation step (a) performed prior to the silicon nitride etch has been found to significantly increase the selectivity of the silicon nitride etch relative to polysilicon surfaces present on microelectronic device substrates.

[0020] In one embodiment, a composition effective for etching silicon nitride comprises at least 60 weight percent, at least 70 weight percent, at least 80 weight percent, or at least 90 weight percent phosphoric acid based on the total weight of the composition.

[0021] In another embodiment, the composition effective for etching silicon nitride further comprises various additives as outlined below.

[0022] In one embodiment, a composition effective for etching silicon nitride comprises: a.Formula: TIFF2025515839000002.tif50170In the formula, A is an aromatic ring or an aromatic heterocycle, and each R 1 are the same or different, hydrogen, hydroxy or hydroxyl, C 1 ~C 20 Alkyl, C 1 ~C 20 Alkylamino, phenyl, benzyl, and C 1 ~C 20 Alkoxy, phenoxy, and C 3 ~C 8 cycloalkyl; x is 0 or 1; each y and y', which may be the same or different, is 0 or is selected from an integer from 1 to 5; z is an integer selected from 1, 2 or 3; m is an integer selected from 1, 2 or 3; w is an integer selected from 0 or 1, 2, 3 or 4, where m+z=4; and / or b.Formula: (R 1 ) 3 Si-M-Si(R 1 ) 3 , In the formula, each R 1 are the same or different and are as defined above, and -M- is selected from -NH- or -O-. The composition further includes the composition comprising:

[0023] In one embodiment, the composition effective for etching silicon nitride may further comprise compounds described in U.S. Patent Application Publication No. 2021 / 0054236, which is incorporated herein by reference. Exemplary compounds include: formula: TIFF2025515839000003.tif42170, where X is O or N; R 2 From R 7 are each independently hydrogen, C 1 ~C 20 Alkyl, C 1 ~C 20 Alkoxy, C 2 ~C 20 Alkenyl, C 3 ~C 20 Cycloalkyl, C 1 ~C 20 Aminoalkyl, C 6 ~C 20 Aryl, C 1 ~C 20 Alkyl carbonyl, C 1 ~C 20 Alkylcarbonyloxy, C 1 ~C 10 cyanoalkyl; z is 0 or 1; R 2 From R 5 At least two of C 1 ~C 20 This includes compounds in which the formula is an alkoxy group.

[0024] In some embodiments, the compositions of the present invention may further comprise at least one silane selected from (a) an alkylaminoalkoxysilane and (b) an alkylaminohydroxylsilane, where the silane has at least one moiety selected from alkoxy and hydroxyl. In one embodiment, the alkylaminoalkoxysilane and alkylaminohydroxylsilane compounds are Tetramethylammonium silicate, N-(3-trimethoxysilylpropyl)diethylenetriamine, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyl silanetriol, N 1 -(3-trimethoxysilylpropyl)diethylenetriamine, N-(6-aminohexyl)aminopropyltrimethoxysilane, (3-aminopropyl)triethoxysilane, and (3-Aminopropyl)silanetriol (APST) and its phosphate esters is selected from.

[0025] Since the above compounds tend to form phosphate esters in an equilibrium reaction in concentrated phosphoric acid solution, in practice at least a portion of such compounds will exist as phosphate esters.

[0026] As used herein, the term "microelectronic device" (or "microelectronic device substrate", or simply "substrate") is used in a manner consistent with the commonly understood meaning of the term in the electronics, microelectronics, and semiconductor manufacturing arts, and refers to, for example, any of a variety of different types of: semiconductor substrates; integrated circuits; solid-state storage devices; hard memory disks; read, write, read-write heads and their mechanical or electronic components; flat panel displays; phase change memory devices; solar panels and other products that contain one or more solar cell devices; photovoltaic cells; and microelectromechanical systems (MEMS) manufactured for use in microelectronics, integrated circuit, energy harvesting, or computer chip applications. It should be understood that the term "microelectronic device" can refer to any in-process microelectronic device or microelectronic device substrate that contains, or is being prepared to contain, functional electronic (current carrying), functional semiconductor, and insulating structures for ultimate electronic utilization in a microelectronic device or microelectronic assembly.

[0027] As used herein, the term "silicon nitride" has a meaning consistent with that of the term as used in the microelectronics and semiconductor manufacturing industries. Consistent therewith, silicon nitride is a material that contains commercially useful low levels of other materials or impurities, and potentially Si. 3 N 4 Silicon nitride refers to materials that include thin films made of amorphous silicon nitride having a variation close to the nominal stoichiometry of 1000 nm to 1000 nm. Silicon nitride may be present as a functional feature of a device, for example as a barrier or insulating layer, as part of a microelectronic device substrate, or to function as a material that facilitates a multi-step manufacturing process for making microelectronic devices.

[0028] As used herein, the term "silicon oxide" refers to a material consistent with the meaning of the term as used in the microelectronics and semiconductor manufacturing industries. Consistent therewith, silicon oxide refers to silicon oxide (SiO x ), e.g., SiO 2 , “thermal oxide” (ThO x ), etc. The silicon oxide can be disposed on the substrate by any method, for example, by chemical vapor deposition from TEOS or another source, or by thermal evaporation. The silicon oxide can advantageously contain low levels of other materials or impurities that are commercially useful. Silicon oxide may be present as a feature of a microelectronic device, for example, as an insulating layer, as part of a microelectronic device substrate.

[0029] As used herein, "polysilicon" or polycrystalline Si or poly-Si is understood by those skilled in the art to be a polycrystalline form of silicon consisting of multiple small silicon crystals. It is typically deposited using low pressure chemical vapor deposition (LPCVD) and is often doped n-type or p-type polysilicon. As will be readily understood by those skilled in the art, the degree of doping can range from lightly doped (e.g., 10 13 cm -3 ~10 18 cm -3range) to highly doped (e.g., 10 18 cm -3 The doping rate can vary from 0.1 to 1.0 (up to 1.0 and above). Examples of p-type doped materials include polysilicon doped with a dopant species from Group IIIA of the periodic table, such as boron, aluminum, gallium, and / or indium. An n-type doped material can be, for example, polysilicon doped with a dopant species from Group IV of the periodic table (silicon, germanium, or tin) or a dopant species from Group V of the periodic table (phosphorus, arsenic, antimony, or bismuth).

[0030] Some etching composition embodiments include a composition in the form of an aqueous solution comprising, consisting essentially of, or consisting of aqueous phosphoric acid (e.g., concentrated phosphoric acid and optionally an amount of added water) in combination with one or more of the above compounds in an amount effective to improve the etch rate of silicon nitride or the selectivity of silicon nitride to polysilicon, and optionally an amount of a fluoride compound effective to provide a desired etch of silicon nitride (including a useful or advantageous etch rate), and / or optionally dissolved silica.

[0031] These and other example compositions can comprise, consist of, or consist essentially of the listed ingredients and optional ingredients. As a general convention throughout this description, a composition of matter, such as a described etching composition, that is said to "consist essentially of" a particular group of ingredients or materials, or ingredients or components thereof, refers to a composition that contains the particular ingredient or material together with minor or insignificant amounts or less of other ingredients or materials, e.g., 5, 2, 1, 0.5, 0.1, or 0.05 parts by weight or less of other ingredients or materials.

[0032] The etching composition includes an amount of aqueous phosphoric acid (e.g., concentrated phosphoric acid) effective to effect the desired etching of silicon nitride. The term "aqueous phosphoric acid" refers to a source of the etching composition that is mixed or combined with other sources of the etching composition to form the etching composition. The term "phosphoric acid solids" refers to the non-aqueous components of the aqueous phosphoric acid source or the non-aqueous components of the etching composition prepared from the aqueous phosphoric acid source.

[0033] The amount of phosphoric acid solids contained in the etching composition may be an amount that, in combination with other materials of the etching composition, provides the desired etching performance, including the desired silicon nitride etch rate and selectivity, which typically requires a relatively high amount (concentration) of phosphoric acid solids. As noted above, the phosphoric acid is present in a proportion of at least 60 weight percent, at least 70 weight percent, at least 80 weight percent, or at least 90 weight percent based on the total weight of the composition of phosphoric acid. In certain embodiments, the phosphoric acid content is about 80-90 weight percent.

[0034] To provide the desired amount of phosphoric acid solids, the composition may contain "concentrated" phosphoric acid as a feedstock that is mixed or combined with other feedstocks (optionally one feedstock is some form of water) to provide the etching composition. "Concentrated" phosphoric acid refers to an aqueous phosphoric acid that contains a large or large amount of phosphoric acid dissolved in a small or small amount of water and is substantially free of other components (e.g., less than 0.5 or 0.1 weight percent of any non-water or non-phosphate solid materials). Concentrated phosphoric acid can be considered to have at least about 80 or 85 weight percent phosphoric acid solids, typically in about 15 or 20 weight percent water. Alternatively, the etching composition may be considered to include a quantity of concentrated phosphoric acid diluted with water or an equivalent formed in any manner, for example, meaning concentrated phosphoric acid diluted with a quantity of water before or after combining with other ingredients of the etching composition. Alternatively, the feedstock of the etching composition may be concentrated or dilute phosphoric acid, and the etching composition may contain an additional amount of water provided to the etching composition, either as a component of a different feedstock or as a separate water feedstock.

[0035] As used herein, the term "fluoride compound" refers to a specific etchant that is optionally added to increase the etch rate of silicon nitride. Such compounds include HF, ammonium fluoride, tetrafluoroboric acid, hexafluorosilicic acid, BF or other compounds containing Si-F bonds, tetrabutylammonium tetrafluoroborate (TBA-BF 4 ), tetraalkylammonium fluoride, and combinations thereof. In one embodiment, the fluoride compounds include HF, ammonium fluoride, tetrafluoroboric acid, hexafluorosilicic acid, tetrabutylammonium tetrafluoroborate, tetra(C 1 ~C 6 alkyl)ammonium, and combinations thereof.

[0036] The amount of optional fluoride compound contained in the composition of the present invention may be an amount that, in combination with other materials of the etching composition, provides the desired etching performance, including the desired silicon nitride etch rate and selectivity. For example, the etching composition may contain an amount of fluoride source compound in the range of about 5 to 10,000 or even up to 50,000 ppm (i.e., 0.0005 to 1 or even 5 weight percent) based on the total weight of the etching composition, such as about 20 to 2,000 ppm (i.e., 0.002 to 0.2 weight percent) based on the total weight of the etching composition. In some embodiments, the composition is free or substantially free of such fluoride compounds. "Substantially free" is defined herein as less than 2 weight percent, less than 1 weight percent, less than 0.5 weight percent, or less than 0.1 weight percent in some embodiments. "Free" is intended in some embodiments to correspond to less than 0.001 weight percent in consideration of environmental contamination, and in other embodiments to correspond to 0.0 weight percent.

[0037] Optionally, the compositions of the present invention may further include an amount of silica dissolved in phosphoric acid ("added silica"), for example, by dissolving a solid silica material in phosphoric acid or by adding a soluble silicon-containing compound capable of forming dissolved silica by reaction with aqueous phosphoric acid, examples of such compounds include (a) TMAS (tetramethylammonium silicate), (b) tetraacetoxysilane, or (c) tetraalkoxysilanes, such as tetramethoxysilane, tetraethoxysilane, etc. The dissolved silica may be effective to improve the selectivity of the etching composition to silicon nitride. The amount may be any useful amount that does not result in supersaturation of the pretreatment silica at the conditions of the etching process, such as about 5 to 10,000 ppm of dissolved silica or soluble silicon-containing compound based on the total weight of the etching composition, or about 20 to 5,000, 3,000, 1,000, or 500 ppm based on the total weight of the etching composition. As with the other additives mentioned above, such compounds tend to form phosphate esters in concentrated phosphoric acid solutions in an equilibrium reaction, and therefore in practice are present at least in part as phosphate esters.

[0038] The etching composition may contain water from one or more sources. For example, water will be present in the aqueous phosphoric acid feedstock. Additionally, water may be used as a carrier for one or more other ingredients of the composition, or water may be added alone as an ingredient in its own right. The amount of water should be sufficiently low so that the composition exhibits desired or preferred or advantageous performance characteristics, including a useful (sufficiently high) silicon nitride etch rate. More water present will tend to increase the silicon nitride etch rate, but may also lower the boiling point of the composition, thereby lowering the use temperature of the composition, which is counterproductive. Exemplary amounts of water from all sources in the etching composition may be less than about 50, 40, or 30 weight percent, such as from about 5 weight percent to about 25 weight percent water based on the total weight of the etching composition, or from about 10 to 20 weight percent water based on the total weight of the etching composition.

[0039] In certain embodiments, the compositions of the present invention do not require, and may exclude, other types of ingredients not typically included in etching compositions, such as solid materials such as pH adjusters and abrasives.

[0040] The compositions of the present invention can be prepared by any method useful for producing the described etching compositions. By one method, aqueous or solid ingredients can be combined, optionally with heating, and mixed to homogenize.

[0041] As mentioned above, the composition described can be useful for the method of removing silicon nitride from the surface of a microelectronic device substrate.The substrate may contain other materials useful for microelectronic devices, such as one or more of insulators, barrier layers, conductive materials, semiconducting materials, or materials useful for processing microelectronic devices (e.g., photoresist, mask, etc.).The substrate of the example has a surface that includes silicon nitride, thermal oxide (ThOx) and PETEOS (oxide deposited using plasma-enhanced tetraethyl orthosilicate) and polysilicon.

[0042] The compositions of the present invention, when used, can provide useful etching performance based on commercial performance demands and expectations, and can provide improved performance in terms of silicon nitride etch rate and selectivity to polysilicon as compared to comparative etching compositions.

[0043] The silicon nitride etch process is effective to at least partially remove the silicon nitride on the surface of the microelectronic device substrate, the phrase "at least partially remove" corresponding to removal of at least about 85%, at least 90%, at least 95%, or at least about 99% of the silicon nitride present on the device prior to particle removal.

[0044] The method can be carried out in known commercially available equipment. Generally, to etch a substrate to selectively remove material from a surface of the substrate, an etching composition can be applied to the surface and contacted with the surface structures to selectively remove certain structures chemically.

[0045] Because the composition is designed to etch oxides very slowly, silicon nitride films may have a thin oxide surface that can inhibit the etching process. In such cases, a very brief treatment with dilute HF can be an advantageous first process step.

[0046] In the etching process, the composition can be applied to the surface by any suitable method, such as by spraying the composition onto the surface; by immersing the substrate in the etching composition (in a static or dynamic volume of the composition); by contacting the surface with another material, such as a pad or fibrous absorbent application element, in which the etching composition has been absorbed; by contacting the substrate with a volume of the etching composition in a circulating pool; or by any other suitable means, method or technique that removes and contacts the etching composition with the surface of silicon-germanium and silicon-containing microelectronic substrates. This application can be done in batch or single-wafer equipment for dynamic or static cleaning.

[0047] Useful etching process conditions (e.g., time and temperature) can be any that have been found to be effective or advantageous. In general, the etching composition is contacted with the surface, for example, by immersion in a bath of the etching composition, for a time sufficient to selectively remove silicon nitride. The exposure time to the etching composition and the temperature of the etching composition can be effective to remove the desired amount of silicon nitride from the surface of the substrate. The time of the etching step should not be too short, since it means that the etching rate of silicon nitride may be too high, which may make process control difficult and reduce the quality of the microelectronic device at the end of the etching step. Of course, it is preferred that the time required for the etching step is not too long to allow good efficiency and throughput of the etching process and the semiconductor manufacturing line. Examples of useful times for the etching step may range from about 5 minutes to about 300 minutes, or from about 10 minutes to about 60 minutes, at temperatures ranging from about 100° C. to about 180° C. Such contact times and temperatures are exemplary, and any other suitable time and temperature conditions effective to achieve the required removal selectivity may be used.

[0048] The etching process herein can be useful for etching silicon nitride material from the surface of any type of substrate. According to certain embodiments, the substrate can include alternating thin film layers of silicon nitride as structural features of the substrate, including alternating thin film layers of silicon oxide and dielectrics such as polysilicon, conductive metal silicides, and zirconium oxide or aluminum oxide and silicon nitride layers. The substrate prior to the etching process includes alternating layers of silicon nitride disposed in openings between high aspect ratio silicon oxide structures. Exemplary etching processes can exhibit good silicon nitride etch rates of greater than about 150, in certain embodiments at least about 2000 or at least about 4000, good selectivity to silicon oxide.

[0049] After selective etching of the desired amount of silicon nitride is complete, the etching composition remaining on the surface of the etched microelectronic device can be removed from the surface by any desired useful method, such as rinsing, cleaning or other removal step using water (or optionally phosphoric acid, followed by water). For example, after etching, the microelectronic device substrate can be rinsed with a rinse of deionized water (e.g., ranging in temperature from about 20 to about 90° C.), followed by, for example, spin drying, N 2 Drying, such as steam drying, may then be performed. After rinsing, the substrate surface may be measured for the presence and amount of particles on the surface.

[0050] The compositions described herein can be easily formulated by simply adding each ingredient and mixing to a homogeneous state. Additionally, the compositions may be easily formulated as single package formulations or multi-component formulations, preferably multi-component formulations, that are mixed at or before the point of use. The individual parts of the multi-component formulation may be mixed at the tool or in a mixing region / area such as an in-line mixer or in a storage tank upstream of the tool. It is contemplated that the various parts of the multi-component formulation may contain any combination of ingredients / components that are mixed together to form the desired composition. It will be understood that the concentration of each ingredient may vary widely in certain semi-aqueous compositions, i.e., more dilute or more concentrated, and that the semi-aqueous composition may variously and alternatively comprise, consist of, or consist essentially of any combination of ingredients consistent with the disclosure herein. Thus, in a third aspect, the present invention provides a method for preparing a semi-aqueous composition comprising: i. a passivation composition according to the first aspect; ii. phosphoric acid; iii. Water; iv. Tetramethylammonium silicate (TMAS), N-(3-trimethoxysilylpropyl)diethylenetriamine, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyl silanetriol, N 1 -(3-trimethoxysilylpropyl)diethylenetriamine, N-(6-aminohexyl)aminopropyltrimethoxysilane, (3-aminopropyl)triethoxysilane, and (3-Aminopropyl)silanetriol (APST) and its phosphate esters and one or more compounds selected from The kit includes two or more of the following in two or more containers:

[0051] The container of the kit should be suitable for storing and transporting the semi-aqueous composition components, for example, NOWPak® containers (Entegris, Inc.). The container or containers that contain the components of the composition preferably include a means for fluidly connecting the components in the container or containers for blending and dispensing. For example, referring to NOWPak® containers, gas pressure may be applied to the outside of a liner in the container or containers to expel at least a portion of the contents of the liner, thus enabling fluid communication for blending and dispensing. Alternatively, gas pressure may be applied to the head space of a conventional pressurized container, and a pump may be used to enable fluid communication. Furthermore, the system preferably includes a distribution port for dispensing the blend composition to a process tool.

[0052] A substantially chemically inert, impurity-free, flexible and resilient polymeric film material, such as high density polyethylene, can be used to manufacture the liner for the one or more containers. Desirable liner materials are generally processed without the need for coextrusion or barrier layers and without any pigments, UV inhibitors, or processing agents that may adversely affect the purity requirements of the components placed in the liner. Desirable liner materials include thin films including virgin (additive-free) polyethylene, virgin polytetrafluoroethylene (PTFE), polypropylene, polyurethane, polyvinylidene chloride, polyvinyl chloride, polyacetal, polystyrene, polyacrylonitrile, polybutylene, and the like. Preferred thicknesses of such liner materials range from about 5 mils (0.005 inches) to about 30 mils (0.030 inches), such as 20 mils (0.020 inches) thick.

[0053] With regard to containers for kits, the disclosures of the following patents and patent applications are incorporated herein by reference in their entirety: U.S. Pat. No. 7,188,644, entitled "APPARATUS AND METHOD FOR MINIMIZING THE GENERATION OF PARTICLES IN ULTRAPURE LIQUIDS"; and U.S. Pat. No. 6,698,619, entitled "RETURNABLE AND REUSABLE, BAG-IN-DRUM FLUID STORAGE AND DISPENSING CONTAINER SYSTEM."

[0054] In the following examples, blanket thin film samples of polysilicon were exposed to 0.5 weight percent HF in water at room temperature for 60 seconds to remove their native oxide. After HF exposure, the films were rinsed with deionized water and subjected to a passivation treatment. After passivation, the samples were then rinsed with deionized water and dried with nitrogen. The polysilicon thickness was then measured using spectroscopic ellipsometry. The samples were then exposed to a selective nitride etch formulation at 160° C. for 2 hours, rinsed, dried, and the polysilicon thickness was measured again. The etch rates in the tables were calculated from the change in polysilicon thickness and the exposure time to the selective nitride formulation. EXAMPLES

[0055] TIFF2025515839000004.tif112170

[0056] Composition B, a silicon nitride etch composition, is as follows: phosphoric acid, water, APST and TMAS. TIFF2025515839000005.tif33170

[0057] Composition A is as follows: TIFF2025515839000006.tif33170

[0058] This data shows that some of the oxide formulations have n + Although it effectively passivated the polysilicon, only composition A had a n + It is shown to be effective in substantially reducing the etching of the polysilicon.

[0059] Aspects

[0060] In a first aspect, the present invention provides a method for producing a composition comprising the steps of: a. about 20 to about 80 weight percent sulfuric acid; b. about 20 to about 80 weight percent water; c. about 0.01 to about 0.4 weight percent sulfurous acid; d. about 0.1 to about 10 weight percent nitric acid, and, optionally, e. about 0.001 to about 0.1 weight percent formic acid; The present invention provides a composition comprising the reaction product of:

[0061] In a second aspect, the present invention provides a method for producing a composition comprising the steps of: a. about 59 to about 65 weight percent sulfuric acid; b. about 36 to about 41 weight percent water; c. about 0.01 to about 0.3 weight percent sulfurous acid; d. about 0.1 to about 0.04 weight percent nitric acid, and, optionally, e. about 0.005 to about 0.1 weight percent formic acid; The present invention provides a composition that is the reaction product of:

[0062] In a third aspect, the present invention provides a composition according to the first aspect, wherein the nitric acid is utilized in an amount of about 0.1 to about 0.25 weight percent based on the total weight of the composition.

[0063] In a fourth aspect, the present invention provides a method for selectively etching silicon nitride on a microelectronic device substrate, the substrate comprising a surface comprising silicon nitride, a surface comprising silicon oxide, and a surface comprising polysilicon, the method comprising: a. exposing a microelectronic device substrate including silicon nitride, silicon oxide, and polysilicon surfaces to a composition including nitrous acid; Next, b. rinsing the substrate with a liquid solution comprising water; c. exposing the substrate to a composition effective to etch silicon nitride under conditions effective to etch silicon nitride.

[0064] In a fifth aspect, the present invention provides a method for selectively etching silicon nitride on a microelectronic device substrate, the substrate comprising a surface comprising silicon nitride, a surface comprising silicon oxide, and a surface comprising polysilicon, the method comprising: a. a microelectronic device substrate comprising a silicon nitride, silicon oxide and polysilicon surface, i. about 20 to about 80 weight percent sulfuric acid; ii. about 20 to about 80 weight percent water; iii. about 0.01 to about 0.4 weight percent sulfurous acid; iv. about 0.1 to about 10 weight percent nitric acid, and, optionally, v. about 0.001 to about 0.1 weight percent formic acid; to a composition comprising the reaction product of Next, b. rinsing the substrate with a liquid solution comprising water; c. exposing the substrate to a composition effective to etch silicon nitride under conditions effective to etch silicon nitride.

[0065] In a sixth aspect, the present invention provides a composition effective for etching silicon nitride comprising: A phosphoric acid; b. A liquid containing water; The method according to the fourth or fifth aspect is provided, comprising:

[0066] In a seventh aspect, the present invention provides a method according to the sixth aspect, wherein the phosphoric acid is present in an amount of about 80 to about 90 weight percent based on the total weight of the composition.

[0067] In an eighth aspect, the present invention provides a composition effective for etching silicon nitride comprising: a.Formula: TIFF2025515839000007.tif50170In the formula, A is an aromatic ring or an aromatic heterocycle, and each R 1 are the same or different, hydrogen, hydroxy or hydroxyl, C 1 ~C 20 Alkyl, C 1 ~C 20 Alkylamino, phenyl, benzyl, and C 1 ~C 20Alkoxy, phenoxy, and C 3 ~C 8 cycloalkyl; x is 0 or 1; each y and y', which may be the same or different, is 0 or is selected from an integer from 1 to 5; z is an integer selected from 1, 2 or 3; m is an integer selected from 1, 2 or 3; w is an integer selected from 0 or 1, 2, 3 or 4, where m+z=4; and / or b.Formula: (R 1 ) 3 Si-M-Si(R 1 ) 3 In the formula, each R 1 are the same or different and are as defined above, and -M- is selected from -NH- or -O-. The method of the sixth aspect further comprises a composition comprising:

[0068] In a ninth aspect, the present invention provides a composition effective for etching silicon nitride comprising: formula: TIFF2025515839000008.tif42170, where X is O or N; R 2 From R 7 are each independently hydrogen, C 1 ~C 20 Alkyl, C 1 ~C 20 Alkoxy, C 2 ~C 20 Alkenyl, C 3 ~C 20 Cycloalkyl, C 1 ~C 20 Aminoalkyl, C 6 ~C 20 Aryl, C 1 ~C 20 Alkyl carbonyl, C 1 ~C 20 Alkylcarbonyloxy, C 1 ~C 10 cyanoalkyl; z is 0 or 1; R 2 From R 5At least two of C 1 ~C 20 The method of the sixth aspect further comprises the compound:

[0069] In a tenth aspect, the present invention provides a composition effective for etching silicon nitride comprising: Tetramethylammonium silicate, N-(3-trimethoxysilylpropyl)diethylenetriamine, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyl silanetriol, N 1 -(3-trimethoxysilylpropyl)diethylenetriamine, N-(6-aminohexyl)aminopropyltrimethoxysilane, (3-aminopropyl)triethoxysilane, and (3-Aminopropyl)silanetriol and its phosphate ester The method of the fourth or fifth aspect is provided, further comprising one or more compounds selected from:

[0070] In an eleventh aspect, the present invention provides a method according to the fourth or fifth aspect, wherein the composition effective for etching silicon nitride comprises about 80 to about 90 weight percent of phosphoric acid, water, tetramethylammonium silicate, and (3-aminopropyl)silanetriol, the total weight percentage being equal to 100%.

[0071] In a twelfth aspect, the present invention provides a method according to the eleventh aspect, wherein the composition effective to etch silicon nitride further comprises a fluoride compound.

[0072] In a thirteenth aspect, the present invention provides a method for producing a composition comprising the steps of: i. a composition according to claim 1; ii. phosphoric acid; iii. Water; iv. tetramethylammonium silicate, N-(3-trimethoxysilylpropyl)diethylenetriamine, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyl silanetriol, N 1 -(3-trimethoxysilylpropyl)diethylenetriamine, N-(6-aminohexyl)aminopropyltrimethoxysilane, (3-aminopropyl)triethoxysilane, and (3-Aminopropyl)silanetriol and its phosphate ester and one or more compounds selected from The kit includes two or more of the following in two or more containers:

[0073] Having thus described several exemplary embodiments of the present disclosure, those skilled in the art will readily appreciate that still other embodiments may be made and used within the scope of the appended claims. Many advantages of the present disclosure encompassed by this document have been set forth in the foregoing description. It will be understood, however, that the present disclosure is in many respects merely illustrative. The scope of the present disclosure is, of course, to be defined in the language in which the appended claims are expressed.

Claims

1. a. about 20 to about 80 weight percent sulfuric acid; b. about 20 to about 80 weight percent water; c. about 0.01 to about 0.4 weight percent sulfurous acid; d. about 0.1 to about 10 weight percent nitric acid, and, optionally, e. about 0.001 to about 0.1 weight percent formic acid; A composition comprising the reaction product of:

2. a. about 59 to about 65 weight percent sulfuric acid; b. about 36 to about 41 weight percent water; c. about 0.01 to about 0.3 weight percent sulfurous acid; d. about 0.1 to about 0.04 weight percent nitric acid, and, optionally, e. about 0.005 to about 0.1 weight percent formic acid; 2. The composition of claim 1 which is the reaction product of:

3. The composition of claim 1, wherein the nitric acid is utilized in an amount of about 0.1 to about 0.25 weight percent, based on the total weight of the composition.

4. 1. A method for selectively etching silicon nitride on a microelectronic device substrate, the substrate including a surface comprising silicon nitride, a surface comprising silicon oxide, and a surface comprising polysilicon, the method comprising: a. exposing a microelectronic device substrate including silicon nitride, silicon oxide, and polysilicon surfaces to a composition including nitrous acid; Next, b. rinsing the substrate with a liquid solution comprising water; c. exposing the substrate to a composition effective to etch silicon nitride under conditions effective to etch silicon nitride; The method includes:

5. 1. A method for selectively etching silicon nitride on a microelectronic device substrate, the substrate including a surface comprising silicon nitride, a surface comprising silicon oxide, and a surface comprising polysilicon, the method comprising: a. a microelectronic device substrate comprising a silicon nitride, silicon oxide and polysilicon surface, vi. about 20 to about 80 weight percent sulfuric acid; vii. about 20 to about 80 weight percent water; viii. about 0.01 to about 0.4 weight percent sulfurous acid; ix. about 0.1 to about 10 weight percent nitric acid, and, optionally, x. about 0.001 to about 0.1 weight percent formic acid; to a composition comprising the reaction product of Next, b. rinsing the substrate with a liquid solution comprising water; c. exposing the substrate to a composition effective to etch silicon nitride under conditions effective to etch silicon nitride; The method includes:

6. A composition effective for etching silicon nitride comprises: a. phosphoric acid; b. A liquid comprising water; The method of claim 5 , comprising:

7. The method of claim 6, wherein the phosphoric acid is present in an amount of about 80 to about 90 weight percent, based on the total weight of the composition.

8. A composition effective for etching silicon nitride comprises: b. formula: In the formula, A is an aromatic ring or an aromatic heterocycle, and each R １ are the same or different, hydrogen, hydroxy or hydroxyl, C １ ~C ２０ Alkyl, C １ ~C ２０ Alkylamino, phenyl, benzyl, and C １ ~C ２０ Alkoxy, phenoxy, and C ３ ~C ８ cycloalkyl; x is 0 or 1; each y and y', which may be the same or different, is 0 or is selected from the integers 1 to 5; z is an integer selected from 1, 2 or 3; m is an integer selected from 1, 2 or 3; w is 0 or an integer selected from 1, 2, 3 or 4, where m+z=4; and / or c. formula: (R) １ ) ３ Si-M-Si(R １ ) ３ 、 In the formula, each R １ are the same or different and are as defined above, and -M- is selected from -NH- or -O-. The method of claim 6 further comprising a composition comprising:

9. A composition effective for etching silicon nitride comprises: formula: where X is O or N; R ２ From R ７ are each independently hydrogen, C １ ~C ２０ Alkyl, C １ ~C ２０ Alkoxy, C ２ ~C ２０ Alkenyl, C ３ ~C ２０ Cycloalkyl, C １ ~C ２０ Aminoalkyl, C ６ ~C ２０ Aryl, C １ ~C ２０ Alkylcarbonyl, C １ ~C ２０ Alkylcarbonyloxy, C １ ~C １０ cyanoalkyl; z is 0 or 1; R ２ From R ５ When z is 0, at least two of １ ~C ２０ 7. The method of claim 6, further comprising the compound of formula: which is an alkoxy group.

10. A composition effective for etching silicon nitride comprises: Tetramethylammonium silicate, N-(3-trimethoxysilylpropyl)diethylenetriamine, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyl silanetriol, N １ -(3-trimethoxysilylpropyl)diethylenetriamine, N-(6-aminohexyl)aminopropyltrimethoxysilane, (3-aminopropyl)triethoxysilane, and (3-aminopropyl)silanetriol and its phosphate ester 7. The method of claim 6, further comprising one or more compounds selected from:

11. 5. The method of claim 4, wherein the composition effective for etching silicon nitride comprises about 80 to about 90 weight percent of phosphoric acid, water, tetramethylammonium silicate, and (3-aminopropyl) silanetriol, the total weight percent being equal to 100%.

12. The method of claim 11 , wherein the composition effective to etch silicon nitride further comprises a fluoride compound.

13. i. the composition of claim 1; ii. phosphoric acid; iii. Water; iv. tetramethylammonium silicate, N-(3-trimethoxysilylpropyl)diethylenetriamine, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyl silanetriol, N １ -(3-trimethoxysilylpropyl)diethylenetriamine, N-(6-aminohexyl)aminopropyltrimethoxysilane, (3-aminopropyl)triethoxysilane, and (3-aminopropyl)silanetriol and its phosphate ester and one or more compounds selected from A kit comprising two or more of the above in two or more containers.

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