Cavity-forming composition

Abstract

Provided are: a cavity-forming composition suitable for forming a cavity by heating between conductive wiring patterns on a semiconductor substrate; and the like. A cavity-forming composition for forming a cavity between conductive wiring patterns on a semiconductor substrate, the cavity-forming composition containing a polymer and a solvent, the polymer including a structural moiety of an alicyclic hydrocarbon and not including a structural moiety of an aromatic hydrocarbon.

Description

Technical Field

[0001] The present invention relates to a cavity-forming composition for forming a cavity between conductive wiring patterns and a method for manufacturing a semiconductor device using the cavity-forming composition. Background Art

[0002] In recent years, semiconductor devices have been trending towards higher integration, and with this, wiring has become smaller. As wiring becomes smaller, the parasitic capacitance between wiring increases. Increased parasitic capacitance between wiring leads to noise and delays in electrical signals.

[0003] Therefore, as a method for reducing parasitic capacitance between wiring, a method of creating gaps between wiring has been proposed (see Patent Document 1). This proposed technique, in a semiconductor device manufacturing method, creates spaces between the wiring by following the following steps: selectively coating the surface of a predetermined first insulating film on a semiconductor substrate to form multiple wirings on the same layer; forming an organic resin film on the surface of the first insulating film selectively coated with the wirings; thinning the organic resin film to expose the surface of the wirings; depositing a sparse second insulating film over the entire surface; removing the organic resin film; and depositing a dense third insulating film. The organic resin film removal step involves O2 plasma treatment. This O2 plasma treatment removes carbon from the second insulating film (organic SOG film), transforming it into a sparse film. As a result, the O2 plasma passes through the second insulating film, allowing the organic resin film (resist film) to be removed (see paragraph

[0023] of Patent Document 1). Furthermore, in order to reduce damage to the substrate caused by the O 2 plasma treatment, a process of removing the organic resin film by heat has also been studied (see Patent Document 2).

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 09-172068

[0007] Patent Document 2: Japanese Patent Application Laid-Open No. 2021-114524 Summary of the Invention

[0008] Problems to be solved by the invention

[0009] In the technique of Patent Document 1, the O2 plasma treatment for removing the organic resin film requires that the O2 plasma pass through the second insulating film, which places significant restrictions on the material of the second insulating film. Furthermore, an apparatus for the O2 plasma treatment is required.

[0010] On the other hand, if the organic resin film can be removed by heating as in the technique of Patent Document 2, the restrictions on the second insulating film are small, and the cost of the heating device can be relatively low compared to an O 2 plasma treatment device.

[0011] However, from the perspective of providing a cavity-forming composition that is suitable for forming a cavity between conductive wiring patterns on a semiconductor substrate by heating and that leaves little residue after thermal decomposition so as not to affect the electrical characteristics of the semiconductor device, the thermally decomposable polymer described in Patent Document 2 cannot be said to be sufficient, and there is room for research.

[0012] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a cavity-forming composition suitable for forming a cavity between conductive wiring patterns on a semiconductor substrate by heating, and a method for manufacturing a semiconductor device using the cavity-forming composition.

[0013] Means for solving problems

[0014] The present inventors conducted intensive research to solve the above-mentioned problems and found that a cavity-forming composition using a material having an alicyclic hydrocarbon structure in the main chain of the polymer exhibits high thermal decomposition properties and produces little residue, thereby solving the above-mentioned problems. On the other hand, a cavity-forming composition using a material having an aromatic hydrocarbon structure in the main chain of the polymer produces a large amount of residue and is not suitable as a cavity-forming composition, thereby completing the present invention.

[0015] That is, the present invention includes the following aspects.

[0016] [1] A cavity-forming composition for forming a cavity between conductive wiring patterns on a semiconductor substrate. It contains a polymer and a solvent, wherein the polymer contains an alicyclic hydrocarbon structural part and does not contain an aromatic hydrocarbon structural part.

[0017] [2] The cavity-forming composition according to [1], wherein the polymer is composed of a condensate of a diepoxy compound and a dicarboxylic acid.

[0018] [3] The cavity-forming composition according to [1] or [2], wherein the polymer contains a disulfide bond.

[0019] [4] The cavity-forming composition according to any one of [1] to [3], further comprising an acid catalyst.

[0020] [5] A method for manufacturing a semiconductor device, comprising the following steps: Step (A) of applying the cavity-forming composition described in any one of [1] to [4] on a semiconductor substrate having a conductive wiring pattern formed thereon; Step (B), after the step (A), heating the semiconductor substrate to form a cavity-forming film made of the cavity-forming composition between the conductive wiring patterns; Step (C), after the step (B), forming an insulating layer on the conductive wiring pattern and on the cavity-forming film between the conductive wiring patterns; and In step (D), after step (C), the semiconductor substrate is heated to burn off the cavity-forming film.

[0021] [6] The method for manufacturing a semiconductor device according to [5], wherein in the step (B), the cavity-forming film is also formed on the conductive wiring pattern. The method for manufacturing the semiconductor element includes a step (E) of removing the cavity-forming film on the conductive wiring pattern before the step (C).

[0022] [7] The method for manufacturing a semiconductor element according to [5] or [6], comprising step (F): between the step (A) and the step (B), removing the cavity-forming film formed from the cavity-forming composition present on the conductive wiring pattern.

[0023] [8] The method for manufacturing a semiconductor element according to any one of [5] to [7], wherein in the step (C), the insulating layer is formed by chemical vapor deposition.

[0024] Effects of the Invention

[0025] According to the present invention, there can be provided a cavity-forming composition suitable for forming a cavity between conductive wiring patterns on a semiconductor substrate by heating, and a method for manufacturing a semiconductor device using the cavity-forming composition. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1A This is a schematic cross-sectional view (part 1) for explaining an example of a method for manufacturing a semiconductor element.

[0027] Figure 1B This is a schematic cross-sectional view (part 2) for explaining an example of a method for manufacturing a semiconductor element.

[0028] Figure 1C This is a schematic cross-sectional view (part 3) for explaining an example of a method for manufacturing a semiconductor element.

[0029] Figure 1DThis is a schematic cross-sectional view (part 4) for explaining an example of a method for manufacturing a semiconductor element.

[0030] Figure 1E This is a schematic cross-sectional view (part 5) for explaining an example of a method for manufacturing a semiconductor element.

[0031] Figure 1F This is a schematic cross-sectional view (part 6) for explaining an example of a method for manufacturing a semiconductor element. DETAILED DESCRIPTION

[0032] (Cavity-forming composition)

[0033] The cavity-forming composition of the present invention is a composition for forming a cavity between conductive wiring patterns on a semiconductor substrate.

[0034] The cavity-forming composition contains a polymer and a solvent.

[0035] The polymer contains alicyclic hydrocarbon structural parts and does not contain aromatic hydrocarbon structural parts.

[0036] Polymers

[0037] The polymer according to the present invention is a polymer containing a structural portion of an alicyclic hydrocarbon and containing no structural portion of an aromatic hydrocarbon.

[0038] The structure of an alicyclic hydrocarbon refers to a structure related to cyclic hydrocarbons excluding aromatic hydrocarbons among cyclic hydrocarbons.

[0039] The alicyclic hydrocarbon may be a saturated hydrocarbon or an unsaturated hydrocarbon, but is more preferably a saturated hydrocarbon.

[0040] The structure of the alicyclic hydrocarbon is not particularly limited as long as the effects of the present invention are exhibited, but is preferably a 5-membered or 6-membered alicyclic hydrocarbon structure.

[0041] The polymer according to the present invention may be a polymer obtained by reacting any monomer combination as long as it has an alicyclic hydrocarbon structure and does not have an aromatic hydrocarbon structural portion, but is preferably a polymer that is a condensate of a diepoxide and a dicarboxylic acid obtained by reacting a diepoxide and a dicarboxylic acid.

[0042] The diepoxy compound is not particularly limited as long as it has two epoxy groups, but preferably has an alicyclic hydrocarbon ring. As the alicyclic hydrocarbon ring, a cyclohexane ring is preferred.

[0043] The dicarboxylic acid is not particularly limited as long as it is a compound having two carboxyl groups.

[0044] Preferred embodiments of the polymers of the present invention include polymers obtained by reacting the diepoxy compounds exemplified below with the dicarboxylic acids exemplified below. The diepoxy compounds and dicarboxylic acids are appropriately combined so that the resulting condensation product has an alicyclic hydrocarbon structure.

[0045] Examples of the diepoxy compound used for obtaining the polymer include the following.

[0046]

[0047] Examples of the dicarboxylic acid used for obtaining the polymer include those shown below.

[0048]

[0049] The polymers involved in the present invention may contain, for example, disulfide bonds.

[0050] When producing a polymer containing a disulfide bond, for example, as exemplified in the above-mentioned examples of dicarboxylic acids, it is preferred that the dicarboxylic acid used to produce the polymer be a substance having a disulfide bond.

[0051] The polymer involved in the present invention may be, for example, a polymer formed by cross-linking in the presence of an acid catalyst.

[0052] Therefore, a preferred embodiment of the cavity-forming composition of the present invention includes a composition containing an acid catalyst in addition to a polymer containing an alicyclic hydrocarbon structural portion and no aromatic hydrocarbon structural portion and a solvent.

[0053] The cavity-forming composition is suitably used in the production of a semiconductor device including the following steps (A) to (D).

[0054] Step (A): Applying a cavity-forming composition on a semiconductor substrate having a conductive wiring pattern formed thereon

[0055] Step (B): After step (A), a step of heating the semiconductor substrate to form a cavity-forming film made of the cavity-forming composition between the conductive wiring patterns

[0056] Step (C): After step (B), a step of forming an insulating layer on the conductive wiring pattern and on the cavity forming film between the conductive wiring patterns. Step (D): After step (C), the semiconductor substrate is heated to burn off the cavity forming film. In step (C), when forming the insulating layer, if the cavity-forming film softens and deforms when heat is applied to the cavity-forming film, it is difficult to form a uniform insulating layer. However, the cavity-forming film formed from the cavity-forming composition of the present invention is not easily softened, so a uniform insulating layer can be formed.

[0057] Furthermore, in step (D), when heating is applied to burn the cavity-forming film, the polymer contained in the cavity-forming composition of the present invention exhibits a high decomposition rate, and thus the cavity-forming film can be burned without leaving any residue.

[0058] Therefore, the cavity-forming composition of the present invention is suitable for forming a cavity between conductive wiring patterns on a semiconductor substrate by heating.

[0059] A preferred embodiment of the cavity-forming composition of the present invention is that the cavity-forming film formed from the cavity-forming composition has a sufficiently high glass transition temperature, for example, 86°C or higher. The higher the glass transition temperature, the more uniform the insulating layer can be formed. The glass transition temperature is more preferably 90°C or higher, further preferably 93°C or higher, and particularly preferably 100°C or higher. The upper limit of the glass transition temperature is not particularly limited, and for example, the glass transition temperature may be 130°C or lower, or 120°C or lower.

[0060] The glass transition temperature can be measured, for example, by the following method.

[0061] The cavity-forming composition was applied by spin coating and baked at a predetermined temperature (e.g., 205°C or 215°C) to form a coating film on a silicon substrate. The coating film thickness was set to 40 nm to 50 nm. The coating film was then scraped off, and the resulting powder was subjected to differential scanning calorimetry.

[0062] Differential scanning calorimetry (DSC) was used for the measurement. First, the temperature was raised to 140°C. After eliminating the thermal history, the temperature was lowered to 0°C at a cooling rate of 20°C / min. The temperature was measured again at a heating rate of 20°C / min. The temperature of the inflection point of the transition region that appeared stepwise in the differential thermal analysis diagram was set as the glass transition temperature. In the case where no inflection point was observed, the glass transition temperature was set to 100°C or above. The apparatus used was a Q2000 manufactured by TA Instruments, and the sample amount was set to approximately 5 mg.

[0063] The baking temperature may be, for example, the heating temperature in the above-mentioned step (B).

[0064] In a preferred embodiment of the cavity-forming composition of the present invention, a cavity-forming film formed from the cavity-forming composition has a decomposition rate of 95% or greater when heated at 400°C for 30 minutes in a nitrogen atmosphere. The higher the decomposition rate, the lower the dielectric constant of the formed cavity (e.g., the cavity formed in step (D)). The decomposition rate is preferably 96% or greater, more preferably 97% or greater, further preferably 98% or greater, and particularly preferably 99% or greater.

[0065] The decomposition rate can be measured, for example, by the following method.

[0066] The cavity-forming composition is applied by spin coating and baked at a predetermined temperature (e.g., 205°C or 215°C) to form a coating film on the silicon substrate. The coating film thickness is set to 40 nm to 50 nm. The baking temperature can be, for example, the heating temperature in step (B) above.

[0067] The thickness of the coating film was measured using VM-3210 (manufactured by SCREEN Semiconductor). The silicon substrate coated with the cavity-forming composition was then heated for 30 minutes using a plate preheated to 400° C. under a nitrogen atmosphere. Finally, the film thickness of the coating film on the resulting substrate was measured again using RE-3100 and RE-3500 (manufactured by SCREEN Semiconductor). The thermal decomposition rate of the coating film was calculated from the obtained results using the following formula 1.

[0068] (Decomposition rate [%]) = 100 × (1-T1 / T0) Formula 1

[0069] T0 = ​​film thickness of the coating before sintering and decomposition

[0070] T1 = film thickness of the coating after sintering and decomposition

[0071] The content of the polymer in the cavity-forming composition is not particularly limited, but is preferably 50% to 100% by mass, more preferably 80% to 100% by mass, and particularly preferably 95% to 100% by mass, relative to the non-volatile components (i.e., components other than the solvent) in the cavity-forming composition. However, when the cavity-forming composition contains an acid catalyst for cross-linking the polymer, the upper limit of the polymer content is preferably 99.9% by mass or less.

[0072] <<Polymer Production Method>>

[0073] The polymerization method for producing the polymer is not particularly limited, and the polymer can be produced using a generally known method.

[0074] For example, a polymer can be produced by dissolving a diepoxide compound, a dicarboxylic acid, and a catalyst in an organic solvent and then reacting them under a nitrogen atmosphere at an elevated temperature.

[0075] The organic solvent used is not particularly limited, and examples thereof include propylene glycol monomethyl ether and propylene glycol monopropyl ether.

[0076] As the catalyst used, for example, tetrabutyl bromide , ethyltriphenylphosphine bromide , ethyltriphenylphosphine iodide Benzyltriphenyl chloride , butyltriphenylphosphine bromide wait.

[0077] The reaction temperature may be, for example, 80 to 120°C.

[0078] The reaction time may be, for example, 1 to 48 hours.

[0079] Solvents

[0080] The solvent used in the cavity-forming composition is not particularly limited as long as it can uniformly dissolve the components that are solid at room temperature, but is preferably an organic solvent generally used in chemical solutions for semiconductor photolithography processes. Specifically, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, methyl cellosolve acetate, ethyl cellosolve acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monomethyl ether acetate, propylene glycol propyl ether acetate, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, cycloheptanone, 4-methyl-2-pentanol, methyl 2-hydroxyisobutyrate, Ethyl 2-hydroxyisobutyrate, ethyl ethoxyacetate, 2-hydroxyethyl acetate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate, methyl 3-ethoxypropionate, methyl pyruvate, ethyl pyruvate, ethyl acetate, butyl acetate, ethyl lactate, butyl lactate, 2-heptanone, methoxycyclopentane, anisole, γ-butyrolactone, N-methylpyrrolidone, N,N-dimethylformamide, and N,N-dimethylacetamide. These solvents can be used alone or in combination of two or more.

[0081] Among these solvents, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, ethyl lactate, butyl lactate, and cyclohexanone are preferred, and propylene glycol monomethyl ether and propylene glycol monomethyl ether acetate are particularly preferred.

[0082] <Acid Catalyst>

[0083] The cavity-forming composition may further contain an acid catalyst.

[0084] The polymer according to the present invention can be cross-linked using an acid catalyst contained in the cavity-forming composition.

[0085] The polymer according to the present invention can be cross-linked with an acid catalyst, thereby increasing the glass transition temperature (Tg) of a cavity-forming film formed by coating a cavity-forming composition containing the polymer.

[0086] Examples of the acid catalyst include sulfonic acid compounds.

[0087] Examples of the sulfonic acid compound include p-toluenesulfonic acid, pyridine Trifluoromethanesulfonate (Py-TFMS), pyridine - p-Toluenesulfonate, 5-sulfosalicylic acid, 4-chlorobenzenesulfonic acid, 4-hydroxybenzenesulfonic acid, pyridine -4-Hydroxybenzenesulfonate, n-dodecylbenzenesulfonic acid, 4-nitrobenzenesulfonic acid, benzenedisulfonic acid, 1-naphthalenesulfonic acid, trifluoromethanesulfonic acid, camphorsulfonic acid.

[0088] The content of the acid catalyst in the cavity-forming composition is not particularly limited, but is, for example, 0 to 5% by mass relative to the polymer.

[0089] <Other ingredients>

[0090] A surfactant may be further added to the cavity-forming composition in order to prevent the generation of pinholes, streaks, and the like and to further improve the coating properties on uneven surfaces. Examples of the surfactant include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, and polyoxyethylene oleyl ether; polyoxyethylene alkylaryl ethers such as polyoxyethylene octylphenol ether and polyoxyethylene nonylphenol ether; polyoxyethylene / polyoxypropylene block copolymers; sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitan trioleate, and sorbitan tristearate; and sorbitan fatty acid esters such as polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan trioleate, and polyoxyethylene sorbitan tristearate. Nonionic surfactants such as polyoxyethylene sorbitan fatty acid esters such as sorbitol tristearate, Eftop EF301, EF303, EF352 (trade names of Tokemu Project), Megafuck F171, F173, R-30, R-40 (trade names of DIC Corporation), Fluorado FC430, F Fluorochemical surfactants such as C431 (trade name, manufactured by Sumitomo Soft-Em Co., Ltd.), Asahigard AG710, Surflon S-382, SC101, SC102, SC103, SC104, SC105, and SC106 (trade name, manufactured by Asahi Glass Co., Ltd.), and organosiloxane polymer KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.) are also available. The amount of these surfactants blended is generally 2.0% by mass or less, preferably 1.0% by mass or less, relative to the total solids content of the protective film-forming composition. These surfactants may be added alone or in combination of two or more.

[0091] The nonvolatile component contained in the cavity-forming composition, that is, the components other than the above-mentioned solvent, is, for example, 0.01% by mass to 10% by mass.

[0092] (Method for manufacturing semiconductor element)

[0093] The method for manufacturing a semiconductor device of the present invention includes the following steps (A) to (D).

[0094] Step (A): A step of applying the cavity-forming composition of the present invention on a semiconductor substrate having a conductive wiring pattern formed thereon

[0095] Step (B): After step (A), a step of heating the semiconductor substrate to form a cavity-forming film made of the cavity-forming composition between the conductive wiring patterns

[0096] Step (C): After step (B), a step of forming an insulating layer on the conductive wiring pattern and on the cavity forming curing material between the conductive wiring patterns. Step (D): After step (C), the semiconductor substrate is heated to burn off the cavity forming film. <Process (A)> Step (A) is a step of applying the cavity-forming composition of the present invention onto a semiconductor substrate on which a conductive wiring pattern is formed.

[0097] Examples of the semiconductor substrate include a silicon wafer, a germanium wafer, and a compound semiconductor wafer such as gallium arsenide, indium phosphide, gallium nitride, indium nitride, and aluminum nitride.

[0098] There are no particular restrictions on the material, size, and shape of the conductive wiring pattern.

[0099] Examples of the material of the conductive wiring pattern include copper, cobalt, ruthenium, molybdenum, chromium, tungsten, manganese, rhodium, nickel, palladium, platinum, silver, gold, and aluminum.

[0100] An insulating layer may be formed on the conductive wiring pattern.

[0101] Examples of the material of the insulating layer include silicon dioxide, silicon oxycarbide, silicon oxynitride, silicon nitride, silicon carbon nitride (SiCN), aluminum nitride, aluminum oxynitride, and aluminum oxide.

[0102] As a method of forming the insulating layer, vapor deposition is mentioned, for example.

[0103] The line width of each wiring of the conductive wiring pattern is not particularly limited, and examples thereof include 3 nm to 50 nm.

[0104] The width of the gap between each wiring of the conductive wiring pattern is not particularly limited, and examples thereof include 3 nm to 50 nm.

[0105] There are no particular restrictions on the method for forming the conductive wiring pattern, and for example, a conventionally known photolithography process can be used.

[0106] The cavity-forming composition is applied onto the semiconductor substrate by an appropriate coating method such as a spinner or a coater.

[0107] <Process (B)>

[0108] The step (B) is a step of heating the semiconductor substrate after the step (A) to form a cavity-forming film made of the cavity-forming composition between the conductive wiring patterns.

[0109] The semiconductor substrate is heated using heating means such as a hot plate.

[0110] When the cavity-forming composition contains an acid catalyst for cross-linking the polymer, the semiconductor substrate is heated in step (B) to form a cross-linked structure of the polymer. As a result, a cavity-forming film formed from the cavity-forming composition containing the cross-linked polymer is obtained.

[0111] The heating temperature here can be appropriately selected depending on the type of polymer and the type of acid catalyst optionally contained in the cavity-forming composition, but is preferably 200 to 260°C.

[0112] The heating time is not particularly limited, but is preferably 30 seconds to 2 minutes.

[0113] <Process (C)>

[0114] The step (C) is a step of forming an insulating layer on the conductive wiring pattern and on the cavity-forming film between the conductive wiring patterns after the step (B).

[0115] The material of the insulating layer is not particularly limited and may be an organic material or an inorganic material. In the case where the insulating layer is an inorganic material, examples thereof include silicon dioxide, silicon oxycarbide, silicon oxynitride, silicon nitride, silicon carbon nitride (SiCN), aluminum nitride, aluminum oxynitride, aluminum oxide, tantalum oxide, titanium oxide, yttrium oxide, lanthanum oxide, hafnium oxide, zirconium oxide, and mixtures thereof.

[0116] The thickness of the insulating layer is not particularly limited, and may be, for example, 0.2 nm to 10 nm.

[0117] The method for forming the insulating layer is not particularly limited, but a chemical vapor deposition method (CVD method) is preferable.

[0118] That is, in step (C), the insulating layer is preferably formed by chemical vapor deposition.

[0119] <Process (D)>

[0120] The step (D) is a step of heating the semiconductor substrate after the step (C) to burn off the cavity-forming film.

[0121] When the cavity-forming film is heated, the cavity-forming film is thermally decomposed and burned due to thermal decomposition of the polymer.

[0122] The heating temperature is not particularly limited as long as it is a temperature at which the cavity-forming film disappears, and can be appropriately selected depending on the type of polymer, etc., but is preferably 300 to 500°C.

[0123] The heating time is not particularly limited, but is preferably 30 to 90 minutes.

[0124] The burnt-off amount (decomposition rate) of the cavity-forming film is desirably 100%, but does not necessarily need to be 100%, and may be 99.9% or less. The decomposition rate is preferably 90% or more, more preferably 95% or more, more preferably 96% or more, more preferably 97% or more, further preferably 98% or more, and particularly preferably 99% or more.

[0125] <Process (E)>

[0126] In step (B), the cavity-forming film may also be formed on the conductive wiring pattern. In this case, the method for manufacturing a semiconductor device preferably includes step (E) of removing the cavity-forming film on the conductive wiring pattern before step (C).

[0127] The cavity-forming film on the conductive wiring pattern can be removed by, for example, etching the cavity-forming film. Etching may be wet etching or dry etching.

[0128] <Process (F)>

[0129] The method may further include a step (F) of removing the cavity-forming composition present on the conductive wiring pattern between the steps (A) and (B).

[0130] The cavity-forming composition on the conductive wiring pattern can be removed by, for example, etching the cavity-forming composition. Etching may be wet etching or dry etching.

[0131] The following uses Figures 1A to 1F An example of a method for manufacturing a semiconductor element will be described.

[0132] First, if Figure 1A As shown, a semiconductor substrate 1 having a conductive wiring pattern 2 formed thereon is prepared.

[0133] Next, as step (A), a cavity-forming composition is applied to the semiconductor substrate 1 on which the conductive wiring pattern 2 is formed. By doing so, the cavity-forming composition 3A is disposed on the conductive wiring pattern 2 and in the gaps between the conductive wiring patterns 2 ( Figure 1B ).

[0134] Next, as step (B), the semiconductor substrate 1 is heated. By doing so, a cavity-forming film 3B ( Figure 1C ).

[0135] Next, as step (E), the cavity forming film 3B located on the conductive wiring pattern 2 is removed ( Figure 1D ).

[0136] Next, as step (C), an insulating layer 4 is formed on the conductive wiring pattern 2 and the cavity forming film 3B located in the gap between the conductive wiring pattern 2 ( Figure 1E ).

[0137] Next, as step (D), the semiconductor substrate 1 is heated to burn off the cavity-forming film 3B between the conductive wiring patterns 2 , thereby forming the cavity 3C between the conductive wiring patterns 2 .

[0138] Through the above, cavities are formed between the conductive wiring patterns on the semiconductor substrate.

[0139] Example

[0140] Next, the present invention will be described in detail with reference to Examples, but the present invention is not limited to these.

[0141] The weight average molecular weights of the polymers shown in the following examples are the results of measurements obtained by gel permeation chromatography (hereinafter referred to as GPC). A GPC apparatus manufactured by Tosoh Corporation was used for the measurements, and the measurement conditions and the like were as follows.

[0142] Column temperature: 40

[0143] Flow rate: 0.35ml / min

[0144] Eluent: tetrahydrofuran (THF)

[0145] Standard sample: Polystyrene (Tosoh Corporation)

[0146] The compounds used in Examples and Comparative Examples are shown below.

[0147]

[0148] <Synthesis example 1>

[0149] In a reaction vessel equipped with a thermometer, a cooling tube and a stirring device, 80.00 g of propylene glycol monomethyl ether, 10.95 g of 2,2'-[cyclohexane-1,4-diylbis(methyleneoxymethylene)]bisoxirane (EX-216L, manufactured by Nagase Chemtex Co., Ltd.), 8.11 g of 3,3'-dithiodipropionic acid (DTDPA) (manufactured by Tokyo Chemical Industry Co., Ltd.) and tetrabutyl bromide were added. 0.94 g of PEG-100 (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved and the temperature was raised to 105° C. under a nitrogen atmosphere.

[0150] After stirring at 105° C. for 24 hours under a nitrogen atmosphere, a solution containing a copolymer was obtained. GPC analysis of the obtained polymer revealed a weight average molecular weight (in terms of standard polystyrene) Mw of 4530.

[0151] <Synthesis example 2>

[0152] In a reaction vessel equipped with a thermometer, a cooling tube, and a stirring device, 80.00 g of propylene glycol monomethyl ether, 12.76 g of diglycidyl ether of 2,2-bis(4-hydroxycyclohexyl)propane (EX-252, manufactured by Nagase Chemtex Co., Ltd.), 6.49 g of 3,3'-dithiodipropionic acid (DTDPA) (manufactured by Tokyo Chemical Industry Co., Ltd.), and tetrabutyl bromide were added. 0.75 g of PEG-1,3-diol (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved and the temperature was raised to 105° C. under a nitrogen atmosphere.

[0153] After stirring at 105° C. for 24 hours under a nitrogen atmosphere, a solution containing a copolymer was obtained. GPC analysis of the obtained polymer revealed a weight average molecular weight (in terms of standard polystyrene) Mw of 5410.

[0154] <Synthesis Example 3>

[0155] In a reaction vessel equipped with a thermometer, a cooling tube and a stirring device, 80.00 g of propylene glycol monomethyl ether, 10.20 g of 3,4-epoxycyclohexylmethyl (3,4-epoxy)cyclohexanecarboxylate (CELLOXIDE 2021P, manufactured by Daicel Co., Ltd.), 8.79 g of 3,3'-dithiodipropionic acid (DTDPA) (manufactured by Tokyo Chemical Industry Co., Ltd.) and tetrabutyl bromide were added. 1.01 g of PEG-100 (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved and the temperature was raised to 105° C. under a nitrogen atmosphere.

[0156] After stirring at 105° C. for 24 hours under a nitrogen atmosphere, a solution containing a copolymer was obtained. GPC analysis of the obtained polymer revealed a weight average molecular weight (in terms of standard polystyrene) Mw of 2660.

[0157] <Synthesis Example 4>

[0158] In a reaction vessel equipped with a thermometer, a cooling tube and a stirring device, 80.00 g of propylene glycol monomethyl ether, 9.25 g of dihydroxymethyltricyclodecane diglycidyl ether (Adekalexin EP-4088L, manufactured by ADEKA Co., Ltd.), 6.05 g of 3,3'-dithiodipropionic acid (DTDPA) (manufactured by Tokyo Chemical Industry Co., Ltd.) and tetrabutyl bromide were added. 0.70 g of PEG-1,3-diol (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved and the temperature was raised to 105° C. under a nitrogen atmosphere.

[0159] After stirring at 105° C. for 24 hours under a nitrogen atmosphere, a solution containing a copolymer was obtained. GPC analysis of the obtained polymer revealed a weight average molecular weight (in terms of standard polystyrene) Mw of 3460.

[0160] <Synthesis Example 5>

[0161] In a reaction vessel equipped with a thermometer, a cooling tube and a stirring device, 80.00 g of propylene glycol monomethyl ether, 10.82 g of bisglycidyl terephthalate (EX-711, manufactured by Nagase Chemtex Co., Ltd.), 8.23 ​​g of 3,3'-dithiodipropionic acid (DTDPA) (manufactured by Tokyo Chemical Industry Co., Ltd.) and tetrabutyl bromide were added. 0.95 g of α-glutamic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved and the temperature was raised to 105° C. under a nitrogen atmosphere.

[0162] After stirring at 105° C. for 24 hours under a nitrogen atmosphere, a solution containing a copolymer was obtained. GPC analysis of the obtained polymer revealed a weight average molecular weight (in terms of standard polystyrene) Mw of 5,980.

[0163] <Synthesis example 6>

[0164] In a reaction vessel equipped with a thermometer, a cooling tube and a stirring device, 80.00 g of propylene glycol monomethyl ether, 5.85 g of 1,6-bis(2,3-epoxypropoxy)naphthalene (HP-4032SS, manufactured by DIC Corporation), 3.24 g of 3,3'-dithiodipropionic acid (DTDPA) (manufactured by Tokyo Chemical Industry Co., Ltd.) and tetrabutyl bromide were added. 0.37 g of α-glutamic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved and the temperature was raised to 105° C. under a nitrogen atmosphere.

[0165] After stirring at 105° C. for 24 hours under a nitrogen atmosphere, a solution containing a copolymer was obtained. GPC analysis of the obtained polymer revealed a weight average molecular weight (in terms of standard polystyrene) Mw of 2870.

[0166] <Synthesis Example 7>

[0167] In a reaction vessel equipped with a thermometer, a cooling tube and a stirring device, 80.00 g of propylene glycol monomethyl ether, 10.53 g of diglycidyl ether of 2,2-bis(4-hydroxycyclohexyl)propane (EX-252, manufactured by Nagase Chemtex Co., Ltd.), 4.64 g of 5-hydroxyisophthalic acid (5HIPA) (manufactured by Tokyo Chemical Industry Co., Ltd.) and tetrabutyl bromide were added. 0.82 g of α-glutamic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved and the temperature was raised to 105° C. under a nitrogen atmosphere.

[0168] After stirring at 105° C. for 24 hours under a nitrogen atmosphere, a solution containing a copolymer was obtained. GPC analysis of the obtained polymer revealed a weight average molecular weight (in terms of standard polystyrene) Mw of 5590.

[0169] (Example 1)

[0170] To 1.93 g of the polymer-containing solution obtained in Synthesis Examples 1 to 7 (solid content concentration 20.0% by mass), 77.3 g of propylene glycol monomethyl ether acetate and pyridine were added. 0.07 g of trifluoromethanesulfonate (Py-TFMS) (manufactured by Tokyo Chemical Industry Co., Ltd.) was added to prepare a 2.0 mass % solution, which was then filtered using a polyethylene microfilter with a pore size of 0.05 μm to prepare a cavity-forming composition.

[0171] The prepared solutions were designated as Examples 1 to 4 and Comparative Examples 1 to 3 as shown in Table 1 below.

[0172] [Table 1]

[0173] (Formation of coating film)

[0174] The cavity-forming compositions prepared in Examples 1 to 4 and Comparative Examples 1 to 3 were each applied by spin coating on a silicon substrate and baked at a predetermined baking temperature for 60 seconds to form a coating film having a thickness of 43 nm.

[0175] (Decomposition performance test based on calcined composition)

[0176] The cavity-forming compositions prepared in Examples 1 to 4 and the cavity-forming compositions prepared in Comparative Examples 1 to 3 were each applied by spin coating and fired at 220°C for 60 seconds to form coating films on a silicon substrate. The coating films had a thickness of approximately 43 nm. The thermal decomposition rate of the resulting coating films was measured.

[0177] Table 2 shows the obtained results of the decomposition rates in the respective Examples and Comparative Examples.

[0178] The details of the measurement conditions of the thermal decomposition rate are as follows.

[0179] First, the thickness of the coating film was measured using VM-3210 (manufactured by SCREEN Semiconductor). Then, the silicon substrate coated with the cavity-forming composition was heated for 30 minutes using a plate preheated to 400°C under a nitrogen atmosphere. Finally, the film thickness of the coating film on the obtained substrate was measured again using RE-3100 and RE-3500 (manufactured by SCREEN Semiconductor). The thermal decomposition rate of the coating film was calculated using the following formula 1 from the obtained results. As a result of the study, the decomposition rate is as shown in Table 2.

[0180] (Decomposition rate [%]) = 100 × (1-T1 / T0) Formula 1

[0181] T0 = ​​film thickness of the coating before sintering and decomposition

[0182] T1 = film thickness of the coating after sintering and decomposition

[0183] [Table 2]

[0184] The decomposition rate is desirably 95% or higher. However, in Comparative Examples 1 to 3, the decomposition rates were less than 95%. In contrast, in Examples 1 to 4, the decomposition rates were all 95% or higher.

[0185] The results in Table 2 indicate that the coating films produced using the cavity-forming compositions of Examples 1 to 4 containing a polymer having an alicyclic hydrocarbon structural portion and no aromatic hydrocarbon structural portion in its main chain all had high decomposition rates.

[0186] Industrial availability

[0187] The cavity-forming composition according to the present invention provides a film having excellent removability of the composition by firing.

[0188] Explanation of symbols

[0189] 1. Semiconductor substrate

[0190] 2 Conductive wiring pattern

[0191] 3A Cavity-forming composition

[0192] 3B Cavity Forming Film

[0193] 3C Cavity

[0194] 4 Insulation layer.

Claims

1. A cavity-forming composition for forming a cavity between conductive wiring patterns on a semiconductor substrate. It contains a polymer and a solvent, wherein the polymer contains an alicyclic hydrocarbon structural part and does not contain an aromatic hydrocarbon structural part. 2 . The cavity-forming composition according to claim 1 , wherein the polymer is composed of a condensate of a diepoxy compound and a dicarboxylic acid. The cavity-forming composition according to claim 1 , wherein the polymer contains a disulfide bond. The cavity-forming composition according to claim 1 , further comprising an acid catalyst.

5. A method for manufacturing a semiconductor device, comprising the following steps: Step (A), coating the cavity-forming composition according to any one of claims 1 to 4 on a semiconductor substrate having a conductive wiring pattern formed thereon; A step (B) of heating the semiconductor substrate after the step (A) to form a cavity-forming film made of the cavity-forming composition between the conductive wiring patterns; Step (C), after step (B), forming an insulating layer on the conductive wiring pattern and on the cavity-forming film between the conductive wiring patterns; as well as A step (D) is performed after the step (C), wherein the semiconductor substrate is heated to burn off the cavity-forming film.

6. The method for manufacturing a semiconductor element according to claim 5, wherein in the step (B), the cavity-forming film is also formed on the conductive wiring pattern. The method for manufacturing a semiconductor element includes a step (E) of removing the cavity-forming film on the conductive wiring pattern before the step (C).

7. The method for manufacturing a semiconductor element according to claim 5, comprising a step (F) of removing a cavity-forming film formed of the cavity-forming composition on the conductive wiring pattern between the steps (A) and (B). 8 . The method for manufacturing a semiconductor device according to claim 5 , wherein in the step (C), the insulating layer is formed by chemical vapor deposition.

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