Method for manufacturing structural body, structural body, and method for manufacturing laminate

Abstract

A method for manufacturing a structural body, the method comprising: a step for preparing an intermediate structural body having a substrate, a resin layer disposed on the substrate, and a groove formed so as to penetrate from the surface of the resin layer to the surface of the substrate; a step for forming a metal layer disposed so as to cover at least a portion of the resin layer of the intermediate structural body and to be embedded in the groove; and a step for obtaining a structural body in which the metal layer is disposed in the groove by grinding the surface of the metal layer and exposing the resin layer.

Description

Method for manufacturing a structure, and method for manufacturing a structure and a laminate

[0001] The present invention relates to a method for manufacturing a structure, and a method for manufacturing a structure and a laminate.

[0002] As electronic devices become smaller, lighter, and more powerful, there is a demand for higher integration of semiconductor substrates (semiconductor wafers) and semiconductor chips (hereinafter also referred to as "substrates, etc.") on which device layers are formed. In recent years, the high integration of substrates, etc. has shifted from two-dimensional integration, which improves the degree of integration within a surface, to three-dimensional integration, in which multiple substrates, etc. are vertically stacked.

[0003] When multiple substrates are stacked vertically, the substrates are generally joined by soldering. However, soldering not only requires high-temperature heating, but also makes it difficult to accommodate narrower wiring pitches. Therefore, hybrid joining, which does not use solder but directly joins electrodes (metal layers), is being considered.

[0004] As a hybrid bonding method, a method of directly bonding substrates and a method of bonding using an adhesive have been proposed (see, for example, Patent Documents 1 to 3). ２ Inorganic layers such as these are bonded together. Because the surfaces of the inorganic layers are relatively hard, voids are easily formed at the bonding interface due to the inclusion of foreign matter. Furthermore, bonding requires heating at a high temperature of approximately 400°C. From the viewpoint of avoiding the formation of such voids and the need for bonding at high temperatures, bonding methods using adhesives have been investigated.

[0005] 1A to 1C are schematic cross-sectional views showing a conventional method for manufacturing a structure using an adhesive. 2A to 2C are schematic cross-sectional views showing a method for manufacturing a laminate by hybrid bonding using the structure of FIG. 1C. First, a patterned metal layer 2 is formed on a substrate 1 by photolithography (see FIG. 1A). Next, an adhesive is applied to cover the metal layer 2, and then a resin layer 3 is formed (see FIG. 1B). Next, the surface of the resin layer 3 is ground to expose the surface of the metal layer 2 (see FIG. 1C).

[0006] Two such structures 4 are prepared, stacked so that the resin layers 3 are in contact with each other, and heated (see FIGS. 2A and 2B ). This heating causes the metal layers 2 to expand or diffuse, filling the gaps between the metal layers 2 and bonding them together. This results in a laminate 5 in which the two structures 4 are bonded together (see FIG. 2C ).

[0007] Japanese Patent Laid-Open No. 4-132258 Japanese Patent Laid-Open No. 2010-226060 Japanese Patent Laid-Open No. 2016-47895

[0008] However, in the above method, when two structures 4 are stacked and heated to bond them, the metal layer 2 does not expand sufficiently, resulting in insufficient bonding between the metal layers 2 (see FIG. 2C ). Therefore, in order to bond the metal layers 2 sufficiently, it is necessary to set strict bonding conditions, such as bonding under high temperature and high pressure.

[0009] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a method for manufacturing a structure, and a method for manufacturing a structure and a laminate, which are capable of sufficiently bonding metal layers together even under mild conditions.

[0010] [1] A method for manufacturing a structure, the method comprising the steps of: preparing an intermediate structure having a substrate, a resin layer disposed on the substrate, and a groove formed so as to penetrate from the surface of the resin layer to the surface of the substrate; forming a metal layer that covers at least a portion of the resin layer of the intermediate structure and is disposed so as to be embedded in the groove; and grinding the surface of the metal layer to expose the resin layer, thereby obtaining a structure in which the metal layer is disposed in the groove. [2] A method for manufacturing a structure according to [1], wherein the resin layer comprises a cured product of a resin composition, and the cured product has a cure rate of 70% or more and 100% or less. [3] A method for manufacturing a structure according to [1] or [2], wherein the resin layer has a composite elastic modulus of 0.1 GPa or more and 20 GPa or less at 23°C. [4] A method for manufacturing a structure according to [1] or [2], wherein the resin layer has an outgassing pressure of 7×10 or less when heated under reduced pressure. －６

[0023] The method for producing a structure according to any one of [1] to [3], wherein the temperature at which the temperature reaches 400°C or higher is 400°C. [5] The method for producing a structure according to any one of [1] to [4], wherein the average particle size of metal crystal particles constituting the surface of the metal layer of the structure is 1 μm or less. [6] The method for producing a structure according to any one of [1] to [5], wherein the proportion of portions of the surface of the metal layer of the structure where the crystal orientations are approximately the same is 50% or more. [7] The method for producing a structure according to any one of [1] to [6], wherein the resin layer has a silanol group on the surface. [8] The method for producing a structure according to any one of [1] to [7], wherein the resin layer comprises a cured product of a resin composition, and the cured product comprises at least one selected from the group consisting of an imide bond, an amide bond, a siloxane bond, an epoxy group, and a benzocyclobutene structure. [9] The method for producing a structure according to any one of [1] to [8], wherein the resin layer comprises a cured product of a resin composition, and the cured product comprises a siloxane bond and at least one of an amide bond and an imide bond.

[10] The method for producing a structure according to any one of [1] to [8], wherein the metal layer contains copper, tin, or silver.

[11] The method for producing a structure according to any one of [1] to

[10] , wherein in the step of preparing an intermediate structure, a groove is formed in a resin layer-coated substrate having the substrate and a resin layer disposed on the substrate, penetrating from the surface of the resin layer to the surface of the substrate, to obtain the intermediate structure.

[12] The method for producing a structure according to any one of [1] to

[11] , wherein in the step of forming the metal layer, the metal layer is formed by electrolytic plating.

[13] The method for producing a structure according to

[12] , further comprising, before the step of forming the metal layer, a step of forming a seed layer so as to cover the surface of the resin layer of the intermediate structure and the inner surface of the groove.

[14] A structure comprising a substrate, a resin layer disposed on the substrate, a groove formed so as to penetrate from the surface of the resin layer to the surface of the substrate, a metal layer disposed so as to be embedded in the groove, and seed layers disposed between the metal layer and the resin layer and between the metal layer and the substrate.

[15] A method for producing a laminate, comprising the steps of: preparing two structures by the method for producing a structure according to any one of [1] to

[13] ; laminating the two structures by bringing the resin layer of one of the structures into contact with the resin layer of the other of the structures; and heating the two laminated structures to bond the metal layers together and to bond the resin layers together, thereby obtaining a laminate.

[16] In the laminating step, the bonding strength between one of the resin layers and the other of the resin layers is 0.05 J / m at 23°C. ２

[17] A method for producing a laminate according to

[15] , comprising the steps of preparing a first structure by the method for producing a structure according to any one of [1] to

[13] , and preparing a second structure having a substrate, an inorganic material layer disposed on the substrate, a groove formed so as to penetrate from a surface of the inorganic material layer to a surface of the substrate, and a metal layer disposed so as to be embedded in the groove, bringing the inorganic material layer of the first structure into contact with the resin layer of the second structure to laminate the first structure and the second structure, and heating the laminated first structure and the second structure to bond the metal layers together and to bond the inorganic material layer and the resin layer together, thereby obtaining a laminate.

[0011] According to the present invention, it is possible to provide a method for manufacturing a structure, a structure, and a laminate, which are capable of sufficiently bonding metal layers together even under mild conditions.

[0012] Figures 1A to 1C are schematic partial cross-sectional views showing a conventional method for manufacturing a structure using an adhesive. Figures 2A to 2C are schematic partial cross-sectional views showing a method for manufacturing a laminate by hybrid bonding using the structure of Figure 1. Figures 3A to 3C are schematic partial cross-sectional views showing a method for manufacturing a structure according to one embodiment of the present invention. Figures 4A and 4B are schematic partial cross-sectional views showing a method for manufacturing a structure according to one embodiment of the present invention. Figures 5A to 5C are schematic partial cross-sectional views showing a method for manufacturing a laminate according to one embodiment of the present invention. Figures 6A to 6C are schematic partial cross-sectional views showing a method for manufacturing a laminate according to another embodiment of the present invention.

[0013] In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits.

[0014] As described above, in the conventional method, when two structures are stacked and bonded, the metal layer does not expand sufficiently, resulting in insufficient bonding between the metal layers. The reason for this is not clear, but is presumed to be as follows.

[0015] In the above method, the adhesive is applied so as to cover the metal layer 2, and then the adhesive is heated to dry or heated to, for example, 200°C or higher to harden, thereby forming the resin layer 3 (see FIG. 1B). However, the heating at this time also heats the metal layer 2, which tends to promote crystallization of the metal layer 2. Therefore, when two structures 4 are stacked and heated to bond them, the metal layer 2 does not expand easily, which is thought to result in insufficient bonding between the metal layers 2 (see FIG. 2C).

[0016] In response to this, the present inventors have discovered a method for obtaining a structure by minimizing the thermal history of the metal layer before bonding two structures. Specifically, a resin layer is formed, and then a metal layer is formed. This prevents the metal layer from being subjected to thermal history before the structure is obtained, thereby suppressing the progression of crystallization of the metal layer due to heating. This allows the metal layer to expand sufficiently during bonding, allowing the metal layers to be bonded well to each other.

[0017] A method for manufacturing a structure according to one embodiment of the present invention will be described below.

[0018] 1. Method for Manufacturing a Structure Figures 3A to 3C and Figures 4A and 4B are schematic partial cross-sectional views showing a method for manufacturing a structure according to one embodiment of the present invention.

[0019] The method for manufacturing the structure of this embodiment includes: 1) preparing an intermediate structure 10A having a substrate 11, a resin layer 12, and a groove 13 (see Figures 3A and 3B); 2) forming a barrier metal layer 14 and a seed layer 15 so as to cover the surface of the resin layer 12 of the intermediate structure 10A and the inner surface of the groove 13 (see Figure 3C); 3) forming a metal layer 16 so as to cover at least a portion of the resin layer 12 on which the barrier metal layer 14 and the seed layer 15 are formed, and to be buried in the groove 13 (see Figure 4A); and 4) obtaining the structure 10 by grinding the surface of the metal layer 16 to expose the resin layer 12 (see Figure 4B).

[0020] Step 1) (Step of Preparing an Intermediate Structure) First, an intermediate structure 10A is prepared, which has a substrate 11, a resin layer 12, and a groove 13 formed so as to penetrate from the surface of the resin layer 12 to the surface of the substrate (see Figures 3A to 3C).

[0021] In this embodiment, first, a substrate with a resin layer is prepared, which includes a substrate 11 and a resin layer 12 (see FIG. 3A). The substrate with a resin layer can be obtained, for example, by applying a resin composition onto the substrate 11 and then curing the resin composition.

[0022] (Substrate 11) The type of substrate 11 is not particularly limited, but is preferably a substrate having a semiconductor substrate and a device layer.

[0023] The material of the semiconductor substrate is not particularly limited, but examples thereof include semiconductors (e.g., Si, InP, GaN, GaAs, InGaAs, InGaAlAs, SiC), sapphire, etc. Among these, Si is preferable. That is, the substrate is preferably a silicon wafer. The silicon wafer may have fine grooves (recesses), fine through-holes, silicon through electrodes (TSV), etc., arranged therein.

[0024] The device layer is disposed on at least one of the surfaces of the semiconductor substrate. Examples of the device layer include memories such as NAND, DRAM, SRAM, and MRAM, LSIs, CMOS image sensors, MEMS, LEDs, SAW devices, and optical devices. The device layer may be disposed on the surface of the semiconductor substrate on which the resin layer 12 is disposed, or on the opposite side.

[0025] The substrate may further include other layers as necessary. The other layers may be insulating layers. The insulating layers are not particularly limited and may be inorganic or organic layers. Examples of materials for the inorganic layers include silicon oxide, silicon nitride, and SiCN (silicon carbonitride). Examples of materials for the organic layers include polyimide resin, polybenzoxazole resin, epoxy resin, and benzocyclobutene resin (Dow, Chem).

[0026] It is preferable that the substrate is in an undiced state.

[0027] (Resin Layer 12) The resin layer 12 can function as, for example, a bonding layer or an insulating layer. The resin material of the resin layer 12 is not particularly limited, but preferably contains a cured product of a resin composition containing a curable resin material, for example, from the viewpoint of further improving bonding properties.

[0028] The cured product of the resin composition preferably contains at least one selected from the group consisting of an imide bond, an amide bond, a siloxane bond, an epoxy group, and a benzocyclobutene structure, and more preferably contains a siloxane bond.

[0029] Examples of cured products having siloxane bonds include divinylsiloxane benzocyclobutene polymers, siloxane imide polymers, siloxane amide polymers, siloxane amide imide polymers, and epoxy-modified siloxane polymers. Among these, cured products having siloxane bonds preferably have a siloxane bond and at least one of an amide bond and an imide bond, and more preferably have a siloxane bond and an imide bond. That is, siloxane imide polymers are more preferred.

[0030] Examples of the structure having a siloxane bond include structures represented by the following formulas (1) to (3).

[0031]

[0032] In a structure having an Si—O bond (siloxane bond), the group bonded to Si may be substituted with an alkylene group, a phenylene group, or the like. For example, a structure having (—O—)x(R1)ySi—(R2)—Si(R1)y(—O—)x or the like (R1 represents a methyl group or the like, R2 represents an alkylene group, a phenylene group or the like, x and y each independently represent an integer of 0 or more, and x+y is 3).

[0033] The curable resin material may be any material that forms the cured product, such as a material that forms a cured product having a siloxane bond, a benzocyclobutene compound (e.g., bisbenzocyclobutene), an epoxy compound, or a siloxane-modified compound (e.g., epoxy-modified siloxane).

[0034] The material that forms a cured product having a siloxane bond is preferably a material that forms a cured product having a siloxane bond and at least one of an amide bond and an imide bond, and more preferably a material that forms a cured product having a siloxane bond and an imide bond.

[0035] Examples of materials that form cured products having siloxane bonds include compounds represented by the following formulas (4) and (5). The structures represented by formulas (1) and (2) can also be produced by heating and reacting the compounds represented by the following formulas (4) and (5).

[0036] The material that forms a cured product having a siloxane bond and at least one of an amide bond and an imide bond may include a compound (A) having an Si—O bond and an amino group, and a crosslinking agent (B) having three or more —C(═O)OX groups (X is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms), at least one of which is a carboxy group.

[0037] Examples of the compound (A) include siloxane diamine, a silane coupling agent having an amino group, or a polymer (siloxane polymer) formed from the silane coupling agent via a siloxane bond (Si—O—Si).

[0038] Examples of siloxane diamines include compounds represented by the following formula (A-1): In formula (A-1), i is an integer of 0 to 4, j is an integer of 1 to 3, and Me is a methyl group.

[0039] Examples of siloxane diamines represented by formula (A-1) include 1,3-bis(3-aminopropyl)tetramethyldisiloxane (i=0, j=1) and 1,3-bis(2-aminoethylamino)propyltetramethyldisiloxane (i=1, j=1).

[0040] Examples of silane coupling agents having an amino group include N-(2-aminoethyl)-3-aminopropylmethyldiethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminoisobutyldimethylmethoxysilane, N-(2-aminoethyl)-3-aminoisobutylmethyldimethoxysilane, N-(2-aminoethyl)-11-aminoundecyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, (aminoethylaminoethyl)phenyltriethoxysilane, methylbenzylaminoethylaminopropyltrimethoxysilane, benzylaminoethylaminopropyltriethoxysilane, 3-ureidopropyltriethoxysilane, (aminoethylamino

[0033] Examples of suitable silanes include (ethyl)phenethyltrimethoxysilane, (aminoethylaminomethyl)phenethyltrimethoxysilane, N-[2-[3-(trimethoxysilyl)propylamino]ethyl]ethylenediamine, 3-aminopropyldiethoxymethylsilane, 3-aminopropyldimethoxymethylsilane, 3-aminopropyldimethylethoxysilane, 3-aminopropyldimethylmethoxysilane, trimethoxy[2-(2-aminoethyl)-3-aminopropyl]silane, diaminomethylmethyldiethoxysilane, methylaminomethylmethyldiethoxysilane, p-aminophenyltrimethoxysilane, N-methylaminopropyltriethoxysilane, N-methylaminopropylmethyldiethoxysilane, (phenylaminomethyl)methyldiethoxysilane, acetamidopropyltrimethoxysilane, and hydrolysates thereof.

[0041] The weight-average molecular weight of compound (A) is not particularly limited, but is preferably from 130 to 10,000, and more preferably from 130 to 2,000. The weight-average molecular weight refers to the weight-average molecular weight in terms of polyethylene glycol measured by gel permeation chromatography (GPC).

[0042] The content of compound (A) in the resin composition is not particularly limited, but can be, for example, 1 to 82 mass%, preferably 5 to 82 mass%, and more preferably 13 to 82 mass%, based on the solid content of the resin composition.

[0043] The crosslinking agent (B) includes a trivalent or tetravalent carboxylic acid compound or a carboxylic acid ester compound. The trivalent or tetravalent carboxylic acid compound or the carboxylic acid ester compound preferably contains a ring (aromatic ring or alicyclic ring) from the viewpoint of obtaining a cured product having high heat resistance, for example.

[0044] Examples of such carboxylic acid compounds include alicyclic carboxylic acids such as 1,3,5-cyclohexanetricarboxylic acid; aromatic carboxylic acids such as pyromellitic acid, 1,4,5,8-naphthalenetetracarboxylic acid, biphenyl-3,3',4,4'-tetracarboxylic acid, benzophenone-3,3',4,4'-tetracarboxylic acid, and 4,4'-oxydiphthalic acid; and fluorinated aromatic carboxylic acids such as 1,4-ditrifluoromethylpyromellitic acid. Examples of carboxylic acid ester compounds also include compounds in which some of the carboxy groups of the above carboxylic acid compounds have been substituted with ester groups.

[0045] The content of the crosslinking agent (B) in the resin composition is not particularly limited, but can be set to a range such that the ratio of the number of carbonyl groups in the crosslinking agent (B) to the total number of nitrogen atoms in the compound (A) is, for example, 0.1 or more and 3.0 or less, preferably 0.4 or more and 2.2 or less.

[0046] The resin composition may further contain a solvent. Examples of the solvent include protic inorganic compounds such as water and heavy water; alcohols such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, ethylene glycol, and propylene glycol; ethers such as tetrahydrofuran and dimethoxyethane; aldehydes and ketones such as acetone, ethyl methyl ketone, and cyclohexane; acid derivatives such as ethyl acetate, butyl acetate, N,N-dimethylformamide, N-methylacetamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone; and sulfur compounds such as dimethyl sulfoxide.

[0047] The resin layer 12 can be formed by applying the above-described resin composition onto the substrate 11 and then heating it to harden it.

[0048] The method for applying the resin composition is not particularly limited, and may be, for example, spin coating, slit coating, spray coating, screen printing, squeegeeing, inkjet printing, or the like.

[0049] The resin composition can be heated to a temperature that allows the curable material to be cured while removing the solvent in the resin composition. The heating temperature is preferably a temperature equal to or higher than the curing temperature of the curable material, for example, 100°C to 450°C, preferably 150°C to 300°C, more preferably 180°C to 200°C.

[0050] The resulting resin layer 12 preferably has a functional group capable of forming a chemical bond on its surface. Examples of such functional groups include amino groups, epoxy groups, vinyl groups, and silanol groups (Si—OH groups). Among these, silanol groups are preferred from the viewpoints of adhesion and heat resistance. These functional groups may be formed by surface treatment after the formation of the resin layer 12, or by treatment with a silane coupling agent, or the like. Alternatively, the resin layer 12 may be formed using a compound containing these functional groups.

[0051] Whether or not silanol groups are present on the surface of the resin layer 12 can be confirmed by surface analysis using time-of-flight secondary ion mass spectrometry (TOF-SIMS). Specifically, using a PHI nanoTOFII (ULVAC-PHI, Inc.) which is a TOF-SIMS, whether or not the resin layer 12 has silanol groups on its surface can be confirmed based on the presence or absence of a peak at a mass-to-charge ratio (m / Z) of 45.

[0052] The cure rate of the cured product of the resin composition contained in the resin layer 12 (the cure rate of the resin layer 12) is preferably, for example, 70% or more. If the cure rate of the resin layer 12 is 70% or more, dry etching or CMP processing can be more easily performed when forming the grooves 13 described below or grinding the surface of the metal layer 16, and the processing speed can be further increased. Furthermore, when multiple structures 10 are stacked, misalignment can be more unlikely to occur. From the same perspective, the cure rate of the resin layer 12 is more preferably 80% or more, and more preferably 90% or more. Furthermore, the upper limit of the cure rate of the resin layer 12 is not particularly limited, and may be 100%, 95% or less, or 90% or less.

[0053] The cure rate of the resin layer 12 can be confirmed by measuring the peak intensity of specific bonds and structures (the sum of the peak intensities when there are multiple peaks, such as imide, amide, etc.) of the resin layer 12 using FT-IR (Fourier transform infrared spectroscopy) and determining the rate of increase or decrease in the peak intensity. Note that when there are band-like peaks that are difficult to separate, such as siloxane bonds, the maximum peak intensity can be used.

[0054] For example, when specific bonds and structures are formed by the curing reaction, the increase rate of peak intensity can be calculated using the following formula, and the calculated value can be used as the curing rate of the resin layer 12. Increase rate of peak intensity (%) = [(peak intensity of specific bonds and structures in resin layer 12) / (peak intensity of specific bonds and structures in resin layer 12 after heating at 300°C for 1 hour)] × 100. Note that background signals can be removed by a conventional method. Furthermore, FT-IR measurement can be performed by a transmission method or a reflection method, as necessary.

[0055] In the above-mentioned rate of increase in peak intensity, when there are a plurality of bonds and structures that cause an increase in peak intensity, the peak intensity may be interpreted as the total intensity of the plurality of peak intensities.

[0056] The composite elastic modulus of the resin layer 12 at 23°C is not particularly limited, but is preferably 0.1 GPa or more and 20 GPa or less, and more preferably 0.1 GPa or more and 10 GPa or less. When the composite elastic modulus is 20 GPa or less, the resin layer 12 is appropriately flexible, making it less likely that voids due to foreign matter will occur at the bonding interface when multiple structures 10 are stacked and bonded so that the resin layers 12 are in contact with each other. When the composite elastic modulus is 0.1 GPa or more, it is less likely that misalignment will occur during bonding.

[0057] The composite elastic modulus of the resin layer 12 at 23° C. is preferably 8 GPa or less, more preferably 6 GPa or less, from the viewpoint of making voids less likely to occur, and more preferably 1 GPa or more, from the viewpoint of further reducing misalignment during bonding.

[0058] The composite elastic modulus of the resin layer 12 at 23°C can be measured by the following method. A resin composition containing a resin material is prepared, spin-coated on a silicon substrate, and then heated at 400°C for 10 minutes to prepare a measurement sample. The unloading-displacement curve of the prepared measurement sample at 23°C is measured using a nanoindentator (product name TI-950 Tribo Indenter, manufactured by Hysitron, Berkovich-type indenter) at a test depth of 20 nm. The composite elastic modulus at 23°C is calculated from the maximum load and maximum displacement according to the calculation method described in the reference (Handbook of Micro / nano Tribology (Second Edition), edited by Bharat Bhushan, CRC Press).

[0059] The composite elastic modulus is defined by the following formula (1). (In the above formula (1), E ｒ : composite elastic modulus E ｉ ν: Young's modulus of indenter (1140 GPa) ｉ : Poisson's ratio of the indenter (0.07) E ｓ : Young's modulus of the measurement sample ν ｓ : Poisson's ratio of the measurement sample)

[0060] The composite elastic modulus of the resin layer 12 can be adjusted by the composition and curing rate of the resin composition. For example, if the curing rate of the resin layer 12 is reduced, the composite elastic modulus tends to be reduced.

[0061] Under reduced pressure, the pressure of the outgas from the resin layer 12 is 7×10 －６ The temperature at which the pressure of the outgas reaches 7×10 Pa is preferably 400° C. or higher, more preferably 420° C. or higher, and even more preferably 440° C. or higher. －６ The temperature at which the pressure reaches 10 Pa is a value measured under a reduced pressure environment. －７ Pa. When the temperature is 400°C or higher, not only can the risk of contamination inside the manufacturing equipment be reduced, but also the outgassing generated from the resin layer 12 can be further reduced when grinding the surface of the metal layer 16 in, for example, step 4) described below, thereby preventing peeling of the metal layer 16. Furthermore, even if the metal layer 16 is exposed to a heating step after bonding, peeling at the bonding surface can be made more difficult. Note that when the outgas pressure is 7×10 －６ The temperature at which Pa is reached may be 600°C or lower, or 550°C or lower.

[0062] The temperature at which the outgas pressure reaches a predetermined value or higher can be measured by the following method. First, the substrate 11 on which the resin layer 12 is formed is cut into a 1 cm x 1 cm square using a dicer (DAD3240 manufactured by Disco Corporation) to obtain a sample. Next, the sample is set in a thermal desorption analyzer (for example, EMD-WA1000S manufactured by ESCO Corporation) and the atmospheric pressure (base pressure) is increased to 10 －７ The outgassing amount is measured at a temperature of 7×10 Pa and a temperature rise rate of 30° C. / min. Specifically, the sample is heated to 650° C. at a rate of 30° C. / min. －６ The surface temperature of the silicon substrate is calculated from the standard data (H ＋ Implanted silicon, CaC ２ O ４ Dripping Ar ＋ The temperature of the thermocouple under the stage is calibrated using the outgassing peak of the silicon wafer (implanted with fluorine).

[0063] Outgas pressure is 7 x 10 －６ The temperature at which the pressure of the outgas reaches 7×10 Pa can be adjusted by adjusting the composition and curing rate of the resin composition. For example, if the curing rate of the resin composition is increased, the pressure of the outgas will be 7×10 Pa. －６ The temperature at which Pa is reached tends to be high.

[0064] The surface roughness (Ra) of the resin layer 12 is not particularly limited, but is preferably 0.01 nm to 1.2 nm, and more preferably 0.1 nm to 1.0 nm, which makes it easier for the resin layers 12 to come into contact with each other when two structures 10 are stacked so that the resin layers 12 are in contact with each other, and makes it easier to perform temporary bonding at low temperatures.

[0065] The surface roughness of the resin layer 12 can be evaluated by morphological observation using a scanning probe microscope (SPM). Specifically, the surface roughness can be measured by using an SPM SPA400 (manufactured by Hitachi High-Technologies Corporation) in dynamic force microscope mode to perform measurements over a 3 μm × 3 μm area.

[0066] The thickness of the resin layer 12 is not particularly limited, but is preferably 10 μm or less, more preferably 8 μm or less, even more preferably 5 μm or less, and particularly preferably 2 μm or less. When the thickness of the resin layer 12 is 10 μm or less, misalignment when stacking and bonding multiple structures 10 together can be more effectively suppressed. In addition, deformation of the substrate 11 due to uneven thickness of the resin layer 12 can also be more effectively suppressed. The lower limit of the thickness of the resin layer 12 is not particularly limited as long as it does not impair adhesiveness, and can be, for example, 0.1 μm or more, preferably 0.3 μm or more, and more preferably 0.5 μm or more.

[0067] (Formation of Grooves 13) Next, in the prepared substrate with a resin layer, grooves 13 are formed so as to penetrate from the surface of the resin layer 12 to the surface of the substrate 11, thereby obtaining an intermediate structure 10A (see FIG. 3B).

[0068] The grooves 13 may be formed in a pattern that corresponds to the electrode pattern of the metal layer 16A, which will be described later.

[0069] The method for forming the grooves 13 is not particularly limited, but may be, for example, dry etching using gas, laser ablation, or the like.

[0070] Step 2) (Step of forming a barrier metal layer 14 and a seed layer 15) Next, a barrier metal layer 14 and a seed layer 15 are formed so as to cover the surface of the resin layer 12 and the inner surface of the groove 13 of the obtained intermediate structure 10A (see Figure 3C).

[0071] The barrier metal layer 14 is a layer for preventing the metal of the metal layer 16 from diffusing into the resin layer 12 and deteriorating the device performance of the substrate 11. The barrier metal layer 14 contains a high-melting-point metal such as tantalum (Ta), tantalum nitride (TaN), or titanium nitride (TiN).

[0072] The seed layer 15 can function as a seed layer for the growth of a plated metal when the metal layer 16 is formed by electrolytic plating. In this embodiment, the seed layer 15 is formed on the barrier metal layer 14.

[0073] The metal contained in the seed layer 15 may be selected depending on the type of the metal layer 16, and examples thereof include copper, titanium, chromium, nickel, and gold. In this embodiment, when the metal layer 16 contains copper, it is preferable that the seed layer 15 also contains copper.

[0074] The barrier metal layer 14 and the seed layer 15 can be formed by, for example, a sputtering method, particularly a long-throw sputtering method in which the directionality of sputtered particles is enhanced, or an IMP (Ion Metal Plasma) method.

[0075] The thicknesses of the barrier metal layer 14 and the seed layer 15 are not particularly limited, but may be, for example, 0.5 μm to 50 μm, preferably 1 μm to 30 μm, and more preferably 5 μm to 20 μm. By setting the thicknesses of these layers within the above ranges, the metal layer 16 can be formed in a shorter time, for example, even when formed by electrolytic plating.

[0076] Step 3) (Step of forming metal layer 16) Next, a metal layer 16 is formed so as to cover at least a portion of the resin layer 12 and to be embedded in the grooves 13 (see FIG. 4A ). In this embodiment, the metal layer 16 is formed so as to cover at least a portion of the resin layer 12 on which the barrier metal layer 14 and the seed layer 15 are formed, including the portion where the grooves 13 are arranged.

[0077] The metal material contained in the metal layer 16 is not particularly limited, and examples thereof include known electrode materials. Specific examples include copper, solder, tin, gold, silver, aluminum, indium, cobalt, tungsten, etc. Among these, the metal layer 16 preferably contains copper, tin, or silver, and more preferably contains copper.

[0078] The method for forming the metal layer 16 is not particularly limited, and may be electrolytic plating, electroless plating, sputtering, or an inkjet method. Of these, it is preferable to form the metal layer 16 by electrolytic plating.

[0079] Step 4) (Step of Grinding Metal Layer 16) The surface of the metal layer 16 is ground to expose the resin layer 12. This allows for obtaining a structure 10 in which the metal layer 16A is disposed in the grooves 13 (see FIG. 4B). The configuration of the structure 10 will be described later.

[0080] The method for grinding the surface of the metal layer 16 is not particularly limited, but examples thereof include fly-cutting, chemical mechanical polishing (CMP), plasma dry etching, etc. For example, in the fly-cutting, a surface planer (DFS8910 (manufactured by Disco Corporation)) or the like can be used. In the CMP, a slurry containing silica or alumina, which is generally used for polishing resins, or a slurry containing hydrogen peroxide and silica, which is generally used for polishing metals, can be used as the slurry. In the plasma dry etching, a fluorocarbon plasma, an oxygen plasma, etc. can be used.

[0081] Other Steps The method for manufacturing the structure 10 according to this embodiment may further include other steps in addition to those described above, as necessary. For example, when the metal layer 16A is exposed in the above step 4), a step of reducing oxides on the surface of the metal layer 16A may be further carried out, as necessary. Examples of reduction methods include heating the structure 10 at 100 to 300°C in an acid atmosphere such as formic acid, or heating the structure 10 in a hydrogen atmosphere.

[0082] (Operation) In the above embodiment, after preparing intermediate structure 10A having substrate 11, resin layer 12, and groove 13, metal layer 16A is formed so as to be embedded in groove 13 to obtain structure 10. In this manner, the step of forming resin layer 12, which involves heating, is performed before forming metal layer 16A. Therefore, high-temperature thermal history is not applied to metal layer 16A until structure 10 is obtained, and therefore progress of crystallization of metal layer 16A due to heating can be suppressed.

[0083] (Modification) In the above embodiment, both the barrier metal layer 14 and the seed layer 15 are formed in step 2), but this is not limiting. For example, the barrier metal layer 14 may be omitted, and only the seed layer 15 may be formed. Furthermore, if the metal layer 16 can be formed without forming the seed layer 15, the above step 2) may be omitted.

[0084] 2. Structure A structure according to one embodiment of the present invention can be obtained by the above-described method for producing a structure.

[0085] That is, as shown in FIG. 4B, the structure 10A has a substrate 11, a resin layer 12, a groove 13 arranged to penetrate from the surface of the resin layer 12 to the surface of the substrate 11, a metal layer 16A arranged to be buried in the groove 13, a barrier metal layer 14, and a seed layer 15.

[0086] The metal layer 16A is disposed so as to be buried in the groove 13. The surface of the metal layer 16A is exposed to the outside. The height of the surface of the metal layer 16A may be the same as or lower than the height of the surface of the resin layer 12.

[0087] As described above, the metal layer 16A has not been subjected to a thermal history, and therefore the metal crystal grains at least near the surface of the metal layer 16A are small and the crystal orientation is relatively uniform. Therefore, the metal expands easily when heated during bonding, allowing for a lower bonding temperature.

[0088] Specifically, the average particle size of the metal crystal particles (crystal grains) constituting the surface of the metal layer 16A is not particularly limited, but is preferably 1 μm or less, and more preferably 500 nm or less. When the average particle size of the metal crystal particles is 1 μm or less, there are more diffusion paths for the metal atoms, which increases the diffusion rate of the metal atoms and allows for a lower bonding temperature. The lower limit of the average particle size of the metal crystal particles is not particularly limited, but may be, for example, 100 nm or more.

[0089] The average particle size of the metal crystal particles can be calculated from a mapping image of crystal orientation obtained by measuring the surface of the metal layer 16A by electron backscatter diffraction (EBSD). Specifically, in the mapping image obtained by measuring the orientations of all pixels in a measurement area including the entire surface of the metal layer 16A by the EBSD method, 100 metal crystal particles are randomly selected, and the particle size of each particle is measured, and the average particle size is calculated.

[0090] The proportion of the surface of the metal layer 16A where the crystal orientations are approximately the same is not particularly limited, but is preferably 50% or more, more preferably 60% or more, and even more preferably 70% or more. The upper limit of the proportion of the surface where the crystal orientations are approximately the same is not particularly limited, but may be, for example, 100% or less, or 90% or less. The proportion of the surface where the crystal orientations are approximately the same can be calculated as the proportion of the area of ​​the surface where the crystal orientations are approximately the same to the area of ​​the entire surface of the metal layer 16A in the crystal orientation mapping image.

[0091] The barrier metal layer 14 and the seed layer 15 are disposed between the metal layer 16A and the resin layer 12, and between the metal layer 16A and the substrate 11. That is, the portions of the metal layer 16A other than the surface are covered with the barrier metal layer 14 and the seed layer 15.

[0092] 3. Method for Producing a Laminate A laminate can be produced using at least two structures including the structure described above. Both of the two structures may be the structure described above, or one may be the structure described above and the other may be a structure other than the structure described above.

[0093] 5A to 5C are schematic partial cross-sectional views showing a method for manufacturing a laminate according to one embodiment of the present invention. In this embodiment, an example in which two of the above structures are stacked to manufacture a laminate will be described.

[0094] The method for manufacturing a laminate according to this embodiment includes: 1) preparing at least two structures 10 (see FIG. 5A); 2) contacting the resin layer 12 of one structure 10 with the resin layer 12 of the other structure 10 to laminate the two structures 10 (see FIG. 5B); and 3) heating the two laminated structures 10 to bond the resin layers 12 together and the metal layers 16A together, thereby obtaining a laminate 20 (see FIG. 5C).

[0095] Step 1) (Step of Preparing Structures) First, two of the structures 10 are prepared (see FIG. 5A). The structures 10 can be prepared by, for example, the method for manufacturing the structure.

[0096] Step 2) (Step of Laminating and Temporarily Bonding) Next, the resin layer 12 of one of the two structures 10 is brought into contact with the resin layer 12 of the other structure 10, thereby laminating the one structure 10 and the other structure 10 (see FIG. 5B ). Specifically, the one structure 10 and the other structure 10 are laminated such that the metal layer 16A of the one structure 10 faces the metal layer 16A of the other structure 10.

[0097] The cure rate of the resin layer 12 is preferably within the above range when laminating one structure 10 and the other structure 10. This allows the resin layer 12 of one structure 10 and the resin layer 12 of the other structure 10 to be more firmly bonded to each other in the step 3) (main bonding step) described below, and also makes it possible to further suppress misalignment of the bond.

[0098] Furthermore, it is preferable that the composite elastic modulus of the resin layer 12 at 23°C be within the above-mentioned range when laminating one structure 10 and the other structure 10. This makes it possible to further suppress misalignment during bonding and to make voids less likely to occur.

[0099] Furthermore, one of the stacked structures 10 may be further temporarily bonded to the other structure 10. The temporary bonding is preferably performed at a temperature of room temperature or higher and 100°C or lower, more preferably at a temperature of room temperature or higher and 50°C or lower, and even more preferably at room temperature.

[0100] The surface energy of the bonding interface between the resin layers 12 when the two structures 10 are temporarily bonded is set to 0.05 J / m from the viewpoint of further suppressing misalignment and inclusion of foreign matter during bonding. ２ It is preferable that the concentration is 0.1 J / m or more. ２ More preferably, it is 0.15 J / m or more. ２ The upper limit of the surface energy of the bonding interface is not particularly limited, but is, for example, 1.0 J / m ２ It may be the following:

[0101] The surface energy (bonding strength) of the bonded interface can be determined by a blade insertion test according to the method described in the non-patent document M.P. Maszara, G. Goetz, A. Cavigila, and J.B.M. McKitterick, Journal of Applied Physics, 64 (1988) 4943-4950. A blade with a thickness of 0.1 mm to 0.3 mm is inserted into the bonded interface of the temporarily bonded laminate (in this embodiment, the interface between the resin layers 12), and the distance from the blade tip to the tip of the crack in the blade insertion direction (the distance from the blade tip to the laminate peeled off) is measured using an infrared light source and an infrared camera. Thereafter, the surface energy can be determined based on the following formula: γ=3×10 ９ ×t ｂ ２ ×E ２ ×t ６ / (32 x L ４ ×E×t ３ ) where, γ: surface energy (J / m ２ ) tb: blade thickness (m) E: Young's modulus (GPa) of the substrate 11 included in the structure t: thickness (m) of the substrate 11 L: peeling distance (m) of the laminate from the blade tip.

[0102] Step 3) (Step of Mainly Bonding) The two stacked structures 10 are heated to bond the resin layers 12 together and the metal layers 16A together, thereby obtaining a stacked body 20 (see FIG. 5C).

[0103] The heating temperature when bonding the two structures 10 may be within a range sufficient to bond at least the metal layers 16A together and the resin layers 12 together. Specifically, the heating temperature is preferably 130°C or higher, more preferably 150°C or higher, and even more preferably 200°C or higher. This allows the metal components (e.g., copper) contained in the metal layers 16A to diffuse, thereby further increasing the bonding strength between the metal layers 16A. The upper limit of the heating temperature is not particularly limited, but from the perspective of further reducing damage to the device, it is, for example, 450°C or lower, preferably 300°C or lower, and more preferably 200°C or lower. Note that the heating temperature refers to the surface temperature of the resin layer 12.

[0104] The heating time can be, for example, 5 minutes to 3 hours, preferably 5 minutes to 1 hour.

[0105] Heating can be carried out by conventional methods, for example using a furnace or a hot plate.

[0106] Furthermore, from the viewpoint of further increasing the bonding strength between the two structures 10, the two structures 10 may be pressurized while the resin layers 12 are in contact with each other. Pressurization and heating may be performed simultaneously.

[0107] The pressure to be applied when pressing the two structures 10 is not particularly limited, but is preferably 0.1 MPa or more and 10 MPa or less, and more preferably 0.1 MPa or more and 5 MPa or less. As the pressing device, a press machine (for example, TEST MINI PRESS manufactured by Toyo Seiki Seisaku-sho, Ltd.) can be used.

[0108] Other Steps The method for manufacturing a laminate may further include other steps as necessary. For example, between 1) the step of preparing the structure 10 and 2) the step of laminating and temporarily bonding, a further step of 4) performing a surface activation treatment on the two resin layers 12 to be bonded may be performed. By performing the surface activation treatment, the bonding strength between the metal layers 16 and between the resin layers 12 can be further increased. In particular, by performing the surface activation treatment on the surface of the metal layer 16A, the diffusion of metals such as copper contained in the metal layer 16A can be further promoted. This allows the heating temperature during metal diffusion to be lowered while further increasing the bonding strength between the metal layers 16A.

[0109] Specific examples of the surface activation treatment include plasma treatment and FAB (Fast Atom Bombardment) treatment.

[0110] (Function) In the above embodiment, as described above, the structure 10 having the metal layer 16A in which the progress of crystallization is suppressed is used. As a result, when two structures 10 are heated and bonded together, the metal layer 16A expands or diffuses sufficiently, and the metal layers 16A can be bonded together satisfactorily.

[0111] (Modification) In the above embodiment, an example is shown in which the two structures are both the above-described structures (see FIG. 4B ) used to manufacture a laminate, but this is not limiting. For example, one of the two structures may be a different structure.

[0112] 6A to 6C are schematic partial cross-sectional views illustrating a method for manufacturing a laminate according to another embodiment of the present invention. For example, the following steps may be performed: 1) preparing the structure 10 (first structure), a second structure 30 (second structure) having a substrate 31, an inorganic material layer 32 disposed on the substrate 31, a groove 33 formed so as to penetrate from the surface of the inorganic material layer 32 to the surface of the substrate 31, and a metal layer 34 disposed so as to be embedded in the groove 33 (see FIG. 6A); 2) contacting the resin layer 12 of the first structure 10 with the inorganic material layer 32 of the second structure to laminate the two structures 10 and 30 (see FIG. 6B); and 3) heating the laminated two structures 10 and 30 to bond the resin layer 12 and the inorganic material layer 32 together and to bond the metal layer 16A and the metal layer 34 together to obtain a laminate 20 (see FIG. 6C).

[0113] The inorganic material layer 32 included in the other structure 30 may be an oxide, carbide, nitride, or the like containing at least one element selected from the group consisting of Si, Ga, Ge, and As, and may be, for example, SiO ２ The inorganic material layer 32 may be formed by CVD, sputtering, or the like.

[0114] In the above step 2), before the structural body 10 and the other structural body 30 are laminated, the inorganic material layer 32 of the other structural body 30 may be subjected to a surface activation treatment.

[0115] This application claims priority from Japanese Patent Application No. 2024-73710, filed April 30, 2024. The contents of the specification and drawings of that application are incorporated herein by reference in their entirety.

[0116] According to the present invention, it is possible to provide a method for manufacturing a structure, a structure, and a laminate, which are capable of sufficiently bonding metal layers together even under mild conditions.

[0117] REFERENCE SIGNS LIST 10 Structure 10A Intermediate structure 11 Substrate 12 Resin layer 13 Groove 14 Barrier metal layer 15 Seed layer 16, 16A, 34 Metal layer 20 Laminate 30 Other structure 32 Inorganic material layer 33 Groove

Claims

1. A method for manufacturing a structure, comprising: preparing an intermediate structure having a substrate, a resin layer disposed on the substrate, and a groove formed so as to penetrate from the surface of the resin layer to the surface of the substrate; forming a metal layer that covers at least a portion of the resin layer of the intermediate structure and is disposed so as to be embedded in the groove; and grinding the surface of the metal layer to expose the resin layer, thereby obtaining a structure in which the metal layer is disposed in the groove.

2. The method for manufacturing a structure according to claim 1, wherein the resin layer contains a cured product of a resin composition, and the cured product has a cure rate of 70% or more and 100% or less.

3. The method for manufacturing a structure according to claim 1, wherein the composite elastic modulus of the resin layer at 23°C is 0.1 GPa or more and 20 GPa or less.

4. When the resin layer is heated under reduced pressure, the pressure of the outgas generated from the resin layer is 7 x 10 －６ The method for manufacturing a structure according to claim 1 , wherein the temperature at which the pressure reaches Pa is 400° C. or higher.

5. The method for manufacturing a structure according to claim 1, wherein the average particle size of the metal crystal particles constituting the surface of the metal layer of the structure is 1 μm or less.

6. The method for manufacturing a structure according to claim 1, wherein the proportion of the surface of the metal layer of the structure where the crystal orientations are approximately the same is 50% or more.

7. The method for producing a structure according to claim 1, wherein the resin layer has silanol groups on the surface.

8. The method for producing a structure according to claim 1, wherein the resin layer comprises a cured product of a resin composition, and the cured product comprises at least one selected from the group consisting of an imide bond, an amide bond, a siloxane bond, an epoxy group, and a benzocyclobutene structure.

9. The method for producing a structure according to claim 1, wherein the resin layer contains a cured product of a resin composition, and the cured product contains a siloxane bond and at least one of an amide bond and an imide bond.

10. The method for manufacturing a structure according to claim 1, wherein the metal layer comprises copper, tin or silver.

11. The method for manufacturing a structure according to claim 1, wherein in the step of preparing the intermediate structure, a groove is formed in a resin layer-attached substrate having the substrate and a resin layer disposed on the substrate, the groove penetrating from the surface of the resin layer to the surface of the substrate, thereby obtaining the intermediate structure.

12. The method for manufacturing a structure according to claim 1, wherein in the step of forming the metal layer, the metal layer is formed by electrolytic plating.

13. The method for manufacturing a structure according to claim 12, further comprising, before the step of forming the metal layer, a step of forming a seed layer so as to cover the surface of the resin layer of the intermediate structure and the inner surface of the groove.

14. A structure comprising: a substrate; a resin layer disposed on the substrate; a groove formed so as to penetrate from the surface of the resin layer to the surface of the substrate; a metal layer disposed so as to be embedded in the groove; and seed layers disposed between the metal layer and the resin layer and between the metal layer and the substrate.

15. A method for manufacturing a laminate, comprising the steps of: preparing two structures by the method for manufacturing a structure according to any one of claims 1 to 13; laminating the two structures by bringing the resin layer of one of the structures into contact with the resin layer of the other of the structures; and heating the two laminated structures to bond the metal layers together and to bond the resin layers together, thereby obtaining a laminate.

16. In the laminating step, the bond strength between one of the resin layers and the other of the resin layers at 23°C is 0.05 J / m ２ The method for producing a laminate according to claim 15, wherein the above is performed.

17. A method for manufacturing a laminate, comprising the steps of preparing a first structure by the method for manufacturing a structure defined in any one of claims 1 to 13, and preparing a second structure having a substrate, an inorganic material layer disposed on the substrate, a groove formed so as to penetrate from the surface of the inorganic material layer to the surface of the substrate, and a metal layer disposed so as to be embedded in the groove; bringing the inorganic material layer of the first structure into contact with the resin layer of the second structure to laminate the first structure and the second structure; and heating the laminated first structure and the second structure to bond the metal layers together and to bond the inorganic material layer and the resin layer together, thereby obtaining a laminate.

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