Methods for manufacturing semiconductor bonding films, die-cutting bonding films, and semiconductor devices

Abstract

An adhesive film for semiconductors is used to attach a semiconductor wafer to a substrate while embedding wires for connection with other semiconductor wafers. The dynamic viscoelasticity of the adhesive film in the range of 90–180°C was measured at a heating rate of 5°C / min and a frequency of 1 Hz. The maximum value of tanδ was 1.0 or less, and the minimum melt viscosity was 10000 Pa·s or less.

Description

Technical Field

[0001] This disclosure relates to a semiconductor bonding film, a die-cutting bonding film, and a method for manufacturing a semiconductor device. Prior Technology

[0002] Sometimes it is necessary to embed conductive lines that connect to other semiconductor wafers using a semiconductor adhesive film used to attach semiconductor wafers to an adhesive substrate (e.g., Patent Document 1). In order to properly embed conductive lines, such a conductive embedding adhesive film is required to have a certain degree of fluidity during its thermosetting process.

[0003] [Patent Document 1] Japanese Patent No. 6135202

[0004] However, conventional adhesive films with a certain degree of fluidity undergo deformation in their thickness direction during thermosetting, sometimes resulting in localized thinning of the adhesive film. This localized thinning can, for example, contribute to cracks in semiconductor wafers. Summary of the Invention

[0005] One aspect of this disclosure relates to the following: for thermosetting semiconductor adhesive films used to attach semiconductor wafers to an adhesive body while embedding wires for connection with other semiconductor wafers, local deformation in the thickness direction of the adhesive film accompanying thermal curing is suppressed.

[0006] One aspect of this disclosure relates to a thermosetting adhesive film for semiconductors, used to bond semiconductor wafers to a substrate while embedding wires for connection with other semiconductor wafers. This adhesive film exhibits a maximum tanδ value below 1.0 and a minimum melt viscosity below 10000 Pa·s in the temperature range of 90–180°C. The aforementioned maximum tanδ value and minimum melt viscosity were determined by measuring the dynamic viscoelasticity of the adhesive film at a heating rate of 5°C / min and a frequency of 1 Hz.

[0007] Another aspect of this disclosure relates to a die bonding film having a dicing film and a semiconductor bonding film disposed on the aforementioned dicing film.

[0008] Another aspect of this disclosure relates to a method for manufacturing a semiconductor device, the method comprising the steps of: placing a second semiconductor wafer and an adhesive film on a structure having a substrate and a first semiconductor wafer mounted on the substrate, with the adhesive film positioned between the structure and the second semiconductor wafer; and thermally curing the adhesive film to attach the second semiconductor wafer to the structure. The adhesive film may be a semiconductor adhesive film. A conductive wire is connected to the first semiconductor wafer, and a portion or all of the conductive wire is embedded by the adhesive film.

[0009] This disclosure includes the following. [1] A thermosetting semiconductor adhesive film is used to bond a semiconductor wafer to a substrate while embedding wires for connection with other semiconductor wafers. The adhesive film exhibits a maximum tanδ value below 1.0 and a minimum melt viscosity below 10000 Pa·s in the temperature range of 90~180℃. The aforementioned maximum value of tanδ and the aforementioned minimum melt viscosity were obtained by measuring the dynamic viscoelasticity of the adhesive film within a temperature range of 90~180℃ under conditions of a heating rate of 5℃ / min and a frequency of 1Hz. [2] As described in [1], a semiconductor bonding film, wherein The adhesive film contains a thermosetting resin containing epoxy resin, a curing agent, and an imidazole compound. [3] As described in [2], a semiconductor bonding film, wherein The content of the aforementioned imidazole compound is 0.30 to 5.0 parts by weight, relative to the content of 100 parts by weight of the aforementioned epoxy resin. [4] The semiconductor adhesive film as described in any one of [1] to [3], wherein The adhesive membrane contains inorganic fillers, and the content of the aforementioned inorganic fillers is 35-50% by mass, based on the mass of the adhesive membrane. [5] The semiconductor adhesive film as described in any one of [1] to [4], wherein The adhesive film contains an elastomer, and the content of the aforementioned elastomer is 15 to 30% by mass, based on the mass of the adhesive film. [6] As described in [5], a semiconductor adhesive film, wherein The aforementioned elastomer contains acrylic resin. [7] The semiconductor adhesive film as described in any one of [1] to [6], wherein The adhesive film has a thickness of 25~80μm. [8] The semiconductor adhesive film as described in any one of [1] to [7], wherein The adhesive film exhibits the aforementioned minimum melt viscosity of over 2500 Pa·s in the range of 90~180°C. [9] As described in [1], a semiconductor bonding film, wherein The adhesive film exhibits the aforementioned lowest melt viscosity of over 2500 Pa·s in the temperature range of 90~180°C. The adhesive membrane contains inorganic fillers and elastomers. Based on the quality of the adhesive film, the content of the aforementioned inorganic filler is 35-50% by mass. Based on the mass of the adhesive film, the content of the aforementioned elastomer is 15-30% by mass.

[10] As described in [9], a bonding film for semiconductors, wherein The aforementioned elastomer contains acrylic resin.

[11] A grain-cutting bonding film, comprising: Cutting membrane; and The semiconductor adhesive film described in any one of [1] to

[10] is disposed on the aforementioned cutting film.

[12] A method for manufacturing a semiconductor device includes the following steps: On a structure having a substrate and a first semiconductor wafer mounted on the substrate, a second semiconductor wafer and an adhesive film are disposed such that the adhesive film is positioned between the structure and the second semiconductor wafer; and The aforementioned adhesive film is thermally cured, thereby attaching the aforementioned second semiconductor wafer to the aforementioned structure. The aforementioned adhesive film is any one of the semiconductor adhesive films described in [1] to

[10] . The wire is connected to the aforementioned first semiconductor chip. A portion or all of the aforementioned wire is embedded by the aforementioned adhesive membrane.

[13] The method described in

[12] , wherein The aforementioned structure also includes spacers disposed on the aforementioned substrate and surrounding the aforementioned first semiconductor wafer. The aforementioned second semiconductor wafer and the aforementioned adhesive film are disposed on the aforementioned structure such that the aforementioned adhesive film is disposed between the aforementioned spacer and the aforementioned second semiconductor wafer.

[14] The method described in

[13] , wherein The adhesive film is thermally cured by contacting the aforementioned adhesive film with the aforementioned first semiconductor wafer.

[15] The method described in any of

[12] to

[14] , wherein The method further includes the step of forming a sealing layer that seals the aforementioned first semiconductor wafer and the aforementioned second semiconductor wafer. [Invention Effects]

[0010] For thermosetting semiconductor adhesive films used to attach semiconductor wafers to an adhesive body while embedding wires for connection with other semiconductor wafers, it is possible to suppress local deformation in the thickness direction of the adhesive film accompanying thermal curing. Simple Explanation of the Diagram

[0011] Figure 1 is a cross-sectional view of an example of a laminated film with an adhesive film. Figure 2 is a cross-sectional view illustrating an example of a method for manufacturing a semiconductor device. Figure 3 is a cross-sectional view illustrating an example of a method for manufacturing a semiconductor device. Figure 4 is a cross-sectional view illustrating an example of a method for manufacturing a semiconductor device. Figure 5 is a cross-sectional view illustrating an example of a method for manufacturing a semiconductor device. Figure 6 is a cross-sectional view illustrating an example of a method for manufacturing a semiconductor device. Figure 7 is a graph showing the relationship between the shear viscosity of the adhesive film and temperature. Figure 8 is a graph showing the relationship between the tanδ of the adhesive film and temperature. Figure 9 shows a schematic cross-sectional view of an evaluation adhesive used to assess the deformation of the adhesive film accompanying curing. Implementation

[0012] This invention is not limited to the following examples. In the following examples, unless specifically stated otherwise, the constituent elements (including steps, etc.) are not essential. The sizes of the constituent elements in the figures are conceptual sizes, and the relative sizes between the constituent elements are not limited to the relationships shown in the figures. The numerical values ​​and ranges illustrated below also do not limit this disclosure.

[0013] In this specification, the numerical range represented by "~" indicates the range encompassed by the values ​​before and after "~" as the minimum and maximum values, respectively. Within the numerical ranges described in this specification, the upper or lower limit of one numerical range can be replaced by the upper or lower limit of other numerical ranges described in different stages. Furthermore, the upper or lower limit of the numerical range described in this specification can also be replaced by the values ​​shown in the embodiments.

[0014] In this specification, (meth)acrylate means acrylate or its corresponding methacrylate. The same applies to other similar terms such as (meth)acrylic acid, (meth)acrylic acid copolymer, etc.

[0015] Figure 1 is a cross-sectional view showing an example of a multilayer film having an adhesive film. The multilayer film 50 shown in Figure 1 sequentially includes a substrate 20, an adhesive film 12, and a protective film 30. The adhesive film 12 can be a thermosetting semiconductor adhesive film used to attach a semiconductor wafer to an adhesive while embedding wires for connection with other semiconductor wafers. The substrate 20 can be a dicing film, in which case the multilayer film 50 can be used as a die-dicing bonding film.

[0016] The adhesive film 12 exhibits a maximum tanδ value below 1.0 and a minimum melt viscosity below 10000 Pa·s within the temperature range of 90~180°C. The maximum and minimum tanδ values ​​were obtained by measuring the dynamic viscoelasticity of the adhesive film 12 at a heating rate of 5°C / min and a frequency of 1Hz.

[0017] When the tanδ of the adhesive film 12 is below 1.0 in the range of 90~180℃, the deformation of the adhesive film 12 during the thermosetting process is suppressed. From the same point of view, the maximum value of the tanδ of the adhesive film 12 in the range of 90~180℃ can be below 0.95, below 0.90, below 0.85, below 0.80, below 0.75, or below 0.70, and can be above 0.50.

[0018] The minimum melt viscosity of the adhesive film refers to the minimum value of the shear viscosity (or complex viscosity η*) measured by dynamic viscoelasticity measurement of the adhesive film 12. The shear viscosity of the adhesive film 12 typically decreases with increasing temperature and then increases with the progress of the curing reaction. When the minimum melt viscosity of the adhesive film 12 is below 10000 Pa·s, the adhesive film 12 can be appropriately embedded with wires, etc. From the same perspective, the minimum melt viscosity of the adhesive film 12 can be below 9000 Pa·s, below 8500 Pa·s, below 8000 Pa·s, below 7500 Pa·s, below 7000 Pa·s, below 6500 Pa·s, below 6000 Pa·s, or below 5500 Pa·s.

[0019] Maintaining a relatively high shear viscosity of the adhesive film 12 within the temperature range of 90–180°C can also help suppress deformation of the adhesive film 12 during the curing process. From this perspective, the minimum melt viscosity of the adhesive film 12 within the temperature range of 90–180°C can be 2500 Pa·s or higher, 3000 Pa·s or higher, or 3500 Pa·s or higher. Adhesive films exhibiting a relatively high minimum melt viscosity within the temperature range of 90–180°C tend to exhibit a maximum tanδ value below 1.0 within the same temperature range.

[0020] The thickness of the adhesive film 12 can be, for example, 1 μm or more, 3 μm or more, 20 μm or more, 30 μm or more, 35 μm or more, 40 μm or more, or 50 μm or more, and can be less than 200 μm, 150 μm or less, 120 μm or less, 80 μm or less, or 60 μm or less. From the viewpoint of attaching a semiconductor wafer to an adhesive while embedding wires for connection with other semiconductor wafers, the thickness of the adhesive film 12 can be 25 to 80 μm.

[0021] Next, the film 12 contains, for example, a thermosetting resin and a curing agent that reacts with the thermosetting resin. The thermosetting resin is a compound that forms a cross-linked structure through a curing reaction including reaction with a curing agent and / or self-polymerization. As an example, epoxy resin, which is a compound having epoxy groups, can be cited. Examples of epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenolic varnish type epoxy resin, cresol varnish type epoxy resin, bisphenol A varnish type epoxy resin, bisphenol F varnish type epoxy resin, niobium type epoxy resin, epoxy resin containing a triphenyl backbone, epoxy resin containing a niobium backbone, triphenol methane type epoxy resin, biphenyl type epoxy resin, xylylene type epoxy resin, biphenyl aralkyl type epoxy resin, naphthalene type epoxy resin, and diglycidyl ether compounds derived from polyfunctional phenolic compounds or polycyclic aromatic compounds (such as anthracene). These can be used alone or in combination of two or more. Epoxy resins can also contain combinations of o-cresol varnish type epoxy resin and bisphenol F type epoxy resin and / or bisphenol A type epoxy resin.

[0022] Curing agents that can be combined with epoxy resins, which are thermosetting resins, can, for example, contain phenolic resins. Examples of phenolic resins used as curing agents include phenolic varnish-type phenolic resins, allylated bisphenol A, allylated bisphenol F, allylated naphthalene glycol, phenol aralkyl resins, and naphthol aralkyl resins. These can also be used alone or in combination of two or more. Phenolic varnish-type phenolic resins are obtained by condensing or co-condensing phenols (e.g., phenol, cresol, resorcinol, catechol, bisphenol A, bisphenol F, phenylphenol, aminophenol) and / or naphthols (e.g., α-naphthol, β-naphthol, dihydroxynaphthyl) with compounds having aldehyde groups such as formaldehyde under an acidic catalyst. Phenolic aralkyl resins and naphthol aralkyl resins are synthesized from phenols (e.g., phenolic varnish, phenol) and / or naphthols with dimethoxy-p-xylene or bis(methoxymethyl)biphenyl.

[0023] The total content of thermosetting resin and curing agent can be, for example, more than 10% by mass or more than 15% by mass, and can be less than 80% by mass, less than 75% by mass, less than 70% by mass, 65% by mass, less than 60% by mass, less than 55% by mass, less than 50% by mass, less than 45% by mass, less than 35% by mass, or less than 30% by mass.

[0024] Adhesive film 12 may contain imidazole compounds. Imidazole compounds are compounds having an imidazole ring, and for example, can function as curing accelerators that promote the curing reaction between epoxy resin and its curing agent (phenolic resin, etc.). The type and content of imidazole compounds can be correlated with the maximum and minimum melt viscosity of adhesive film 12. Imidazole compounds with low softening or melting points tend to increase the maximum and minimum melt viscosity of tanδ. For example, at least one imidazole compound selected from the group consisting of 1-cyanoethyl-2-phenylimidazolium, 2-phenylimidazolium, and 1-benzyl-2-methylimidazolium tends to readily provide adhesive films with a maximum tanδ of 1.0 or less and / or a minimum melt viscosity of 10,000 Pa·s or less (or 2,500 Pa·s or more and 10,000 Pa·s or less).

[0025] When the content of imidazole compound is high, the maximum value of tanδ and the minimum melt viscosity tend to increase. For example, based on the mass of adhesive film 12, the content of imidazole compound can be 0.06% by mass or more, 0.07% by mass or more, 0.08% by mass or more, 0.09% by mass or more, 0.10% by mass or more, or 0.11% by mass or more, and can be less than 1.0% by mass, less than 0.90% by mass, less than 0.80% by mass, less than 0.70% by mass, less than 0.60% by mass, less than 0.5% by mass, less than 0.40% by mass, less than 0.30% by mass, or less than 0.20% by mass.

[0026] In the case where the thermosetting resin contains epoxy resin, from the same point of view as described above, the imidazole content, relative to 100 parts by weight of epoxy resin, can be 0.30 parts by weight or more, 0.35 parts by weight or more, 0.40 parts by weight or more, 0.45 parts by weight or more, or 0.50 parts by weight or more, and can be 5.0 parts by weight or less, 4.5 parts by weight or less, 4.0 parts by weight or less, 3.5 parts by weight or less, 3.0 parts by weight or less, 2.5 parts by weight or less, 2.0 parts by weight or less, 1.5 parts by weight or less, 1.0 parts by weight or less, 0.95 parts by weight or less, 0.90 parts by weight or less, 0.85 parts by weight or less, 0.80 parts by weight or less, 0.75 parts by weight or less, 0.70 parts by weight or less, 0.65 parts by weight or less, or 0.60 parts by weight or less.

[0027] When using curing accelerators other than imidazole compounds, by appropriately adjusting their reactivity and content, it is also possible to obtain adhesive films exhibiting a maximum tanδ of less than 1.0 and / or a minimum melt viscosity of less than 10000 Pa·s (or more than 2500 Pa·s and less than 10000 Pa·s).

[0028] The adhesive membrane 12 may also contain inorganic fillers. When inorganic fillers are introduced, the maximum and minimum tanδ values ​​of the adhesive membrane 12 tend to increase. Based on the mass of the adhesive membrane 12, the content of inorganic fillers can be 10% or more by mass, 15% or more by mass, 20% or more by mass, 25% or more by mass, 30% or more by mass, or 35% or more by mass, and can be less than 60% by mass, less than 55% by mass, less than 50% by mass, or less than 45% by mass.

[0029] Inorganic fillers may, for example, contain particles of at least one inorganic material selected from aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, calcium oxide, magnesium oxide, aluminum oxide, aluminum nitride, aluminum borate whiskers, boron nitride, and silicon dioxide. From the viewpoint of adjusting melt viscosity, inorganic fillers may contain silicon dioxide.

[0030] From a flowability perspective, the average particle size of inorganic fillers can be greater than or equal to 0.01 μm or 0.03 μm, and can be less than or equal to 1.5 μm, 1.0 μm, 0.8 μm, 0.08 μm, or 0.06 μm. Two or more inorganic fillers with different average particle sizes can also be combined. The average particle size refers to the value calculated based on the BET specific surface area.

[0031] Adhesive film 12 may contain elastomer. When elastomer is introduced, the maximum and minimum tanδ of adhesive film 12 tend to increase. Based on the mass of adhesive film 12, the elastomer content may be 5% or more by mass, 10% or more by mass, or 15% or more by mass, and may be less than 50% by mass, less than 45% by mass, less than 40% by mass, less than 35% by mass, or less than 30% by mass.

[0032] The elastomer may contain acrylic resin. Here, acrylic resin refers to a polymer containing monomer units derived from (meth)acrylate. Based on the total amount of acrylic resin, the content of (meth)acrylate constituent units in the acrylic resin may be, for example, 70% by mass or more, 80% by mass or more, or 90% by mass or more. The acrylic resin may contain monomer units derived from (meth)acrylate with crosslinking functional groups such as hydroxyl groups having epoxy, alcoholic, or phenolic properties, and carboxyl groups. The acrylic resin may be acrylic rubber, which is a copolymer containing (meth)acrylate and acrylonitrile as monomer units.

[0033] The glass transition temperature (Tg) of an elastomer (such as an acrylic resin) can be above -50°C, above -30°C, above 0°C, or above 3°C, and can be below 50°C, below 45°C, below 40°C, below 35°C, below 30°C, or below 25°C. The glass transition temperature (Tg) refers to the value measured using a DSC (Differential Scanning Calorimeter) (e.g., Rigaku Corporation's "Thermo Plus 2"). By adjusting the type and content of the constituent units of the elastomer (in the case of acrylic resins, units derived from (meth)acrylates), the Tg of the elastomer can be adjusted to a desired range.

[0034] The weight-average molecular weight (Mw) of the elastomer (e.g., acrylic resin) can be above 100,000, above 200,000, or above 300,000, and can be below 3 million, below 2 million, or below 1 million. When the Mw of the elastomer is within such a range, it tends to easily and appropriately control the viscoelasticity of the adhesive film 12. Mw refers to the value measured by gel permeation chromatography (GPC) and converted using a calibration curve based on standard polystyrene.

[0035] Examples of commercially available acrylic resins include SG-70L, SG-708-6, WS-023 EK30, SG-280 EK23, SG-P3 (all manufactured by Nagase ChemteX Corporation), and H-CT-865 (manufactured by Resonac Corporation).

[0036] Next, membrane 12 may also contain a coupling agent. The coupling agent may also be a silane coupling agent. Examples of silane coupling agents include γ-ureopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, 3-phenylaminopropyltrimethoxysilane, and 3-(2-aminoethyl)aminopropyltrimethoxysilane. These may be used alone or in combination of two or more.

[0037] Membrane 12 may also contain other components such as pigments, ion scavengers, and antioxidants.

[0038] The substrate 20 constituting the laminated film 50 can be a resin film. Examples of resin films include those made of polytetrafluoroethylene, polyethylene, polypropylene, polymethylpentene, polyethylene terephthalate, or polyimide. The thickness of the resin film as the substrate 20 can be, for example, 60-200 μm or 70-170 μm.

[0039] The substrate 20 can be a dicing film, and the laminated film 50 can be a dicing grain bonding film. The dicing grain bonding film can be in the form of a strip.

[0040] Examples of cutting films include resin films such as polytetrafluoroethylene (PTFE) films, polyethylene terephthalate (PET) films, polyethylene films, polypropylene films, polymethylpentene (PMM) films, and polyimide films. Depending on the requirements, the cutting film can also be a resin film that has undergone surface treatment by primer coating, UV treatment, corona discharge treatment, grinding treatment, or etching treatment. The cutting film can be adhesive. An adhesive cutting film can be, for example, an adhesive resin film, or a laminate containing a resin film and an adhesive layer disposed on one side thereof. The adhesive layer can be formed by a pressure-sensitive or UV-curable adhesive. A pressure-sensitive adhesive is an adhesive that exhibits constant adhesion under short-term pressure. A UV-curable adhesive is an adhesive whose adhesion decreases upon irradiation by radiation (e.g., ultraviolet light). The thickness of the adhesive layer can be appropriately set according to the shape and size of the semiconductor device, for example, it can be 1~100μm, 5~70μm, or 10~40μm. From the point of view of economy and film operability, the thickness of the substrate 20 as the cutting film can be 60~150μm or 70~130μm.

[0041] The protective film 30 can be the same resin film as the substrate 20. The thickness of the protective film 30 can be, for example, 15~200μm or 70~170μm.

[0042] Figures 2, 3, 4, 5 and 6 are cross-sectional views illustrating an example of a method for manufacturing a semiconductor device using the aforementioned adhesive film 12.

[0043] As shown in Figure 2, an example of a method for manufacturing a semiconductor device includes the following steps: preparing a structure 15 having a substrate 1 and a first semiconductor wafer T1 mounted on the substrate 1; and preparing a wafer TA with an adhesive having a second semiconductor wafer T2 and an adhesive film 12 attached thereto. The structure 15 also has a plurality of spacers 3 disposed on the substrate 1 and surrounding the first semiconductor wafer.

[0044] A first semiconductor wafer T1 is attached to a substrate 1 via a first adhesive film 11. The first semiconductor wafer T1 is connected to a wire w on its side opposite to the substrate 1. The first semiconductor wafer T1 can be a controller wafer. The substrate 1 can be an organic substrate or a metal substrate such as a lead frame. The thickness of the substrate 1 can be, for example, 90~300 μm. The spacer 3 can be a spacer commonly used in semiconductor devices with dolmen structures. The height of the spacer 3 from the substrate 1 can be greater than the height of the first semiconductor wafer T1 from the substrate 1.

[0045] The adhesive-coated wafer TA formed from the second semiconductor wafer T2 and the adhesive film 12 can be prepared, for example, using a die-cutting bonding film having the same structure as the stacked film 50 illustrated in FIG. 1. In this case, for example, the stacked film 50 (die-cutting bonding film) is attached to one side of the semiconductor wafer with the adhesive film 12 in contact with the semiconductor wafer. The side on which the adhesive film 12 is attached can be the circuit side of the semiconductor wafer or the back side opposite to it. The semiconductor wafer with the stacked film 50 (die-cutting bonding film) attached is divided by dicing, thereby forming a monolithic second semiconductor wafer T2. Examples of dicing include cutting with a rotary blade and cutting the adhesive film 12 together with the semiconductor wafer using a laser. The adhesion of the dicing film can also be reduced by irradiating with ultraviolet light after dicing. The second semiconductor wafer T2 and the divided adhesive film 12 are picked up together.

[0046] The thickness of the second semiconductor wafer T2 can be, for example, 1 to 100 μm. The width of the second semiconductor wafer T2 can be, for example, 20 mm or less. The width (or the length of one side) of the second semiconductor wafer T2 can be 3 to 15 mm or 5 to 10 mm.

[0047] As shown in Figure 3, the second semiconductor wafer T2 and the adhesive film 12 are disposed on the structure 15 such that the adhesive film 12 is disposed between the structure 15 and the second semiconductor wafer T2. In the example of Figure 3, the adhesive film 12 is disposed on the spacer 3 of the structure 15, and the adhesive film 12 is separated from the first semiconductor wafer T1. By thermally curing the adhesive film 12 in this state, as shown in Figure 4, the second semiconductor wafer T2 is attached to the structure 15 (the adherend). The thermally cured adhesive film 12 contacts the first semiconductor wafer T1 and embeds a portion of the wire w connected to the first semiconductor wafer T1. The heating temperature for thermally curing the adhesive film 12 can be constant or can be varied in stages. The maximum heating temperature can be 90~180°C. The adhesive film 12 is thermally cured under pressure, atmospheric pressure, or depressurization. The adhesive film 12, designed based on the maximum and / or minimum melt viscosity of tanδ, can properly embed the conductor w through the moderate flow of the thermosetting process, and can form a cured product that suppresses local deformation in its thickness direction.

[0048] Next, as shown in FIG. 5, a wire w is provided to connect the second semiconductor wafer T2 and the substrate 1. Furthermore, a third semiconductor wafer T3 and a fourth semiconductor wafer T4 can be sequentially deposited on the side of the second semiconductor wafer T2 opposite to the substrate 1 via an adhesive film 13. A wire w is provided to connect the third semiconductor wafer T3 or the fourth semiconductor wafer T4 to the substrate 1. In the example of FIG. 5, the number of semiconductor wafers deposited on the spacer 3 is 3, but this number can also be 4 or more.

[0049] As shown in Figure 6, a semiconductor device 100 with a support structure is obtained by forming a sealing layer 60, which seals a structure having a plurality of semiconductor wafers including a first semiconductor wafer T1 and a second semiconductor wafer T2. The sealing layer 60 also fills the vicinity of the end of the first semiconductor wafer. If there is local deformation in the thickness direction on the adhesive film 12, the sealing layer 60 may penetrate into it, potentially causing defects such as cracks on the second semiconductor wafer T2. By suppressing the deformation of the adhesive film 12, such defects can be avoided. [Example]

[0050] The present invention is not limited to the following embodiments.

[0051] 1. Fabrication of the adhesive membrane Adhesive varnishes containing the following materials in the amounts (parts by mass) shown in Table 1 were prepared. The contents of SG-P3 (elastomer) and SC2050-HLG shown in Table 1 are the amounts of solid components (acrylic rubber or silica filler) after solvent removal. (A) Epoxy resin • N-500P-10 (trade name, manufactured by DIC Corporation, o-cresol phenolic resin for clear varnish, epoxy equivalent: 203 g / eq) EXA-830CRP (trade name, manufactured by DIC Corporation, bisphenol F type epoxy resin, epoxy equivalent: 158~168g / eq) (B) Curing agent (phenolic resin) MEH-7800M (trade name, manufactured by Meiwa Chemical Industry Co., Ltd., phenolic resin for varnish, hydroxyl equivalent: 175 g / eq, softening point: 61~90℃) (C) Inorganic packing •SC2050-HLG (trade name, manufactured by Admatechs Co., Ltd., silica filler dispersion, average particle size: 0.50μm) (D) Elastomer ·SG-P3 (trade name, acrylic rubber, weight average molecular weight: 800,000, Tg: 12℃, cyclohexanone solution) (E) Coupling agent Z-6119 (trade name, manufactured by Dow Toray Co., Ltd., 3-ureidopropyltriethoxysilane) • A-189 (trade name, manufactured by Nippon Unicar Company Limited, γ-mercaptopropyltrimethoxysilane) (F) Curing accelerator ·2PZ-CN (trade name, manufactured by SHIKOKU CHEMICALS CORPORATION, 1-cyanoethyl-2-phenylimidazolium)

[0052] Each adhesive varnish prepared was filtered through a 500-mesh filter and then defoamed under vacuum. The defoamed adhesive varnish was then coated onto a polyethylene terephthalate (PET) film (support film) that had undergone a demolding treatment. The coating was dried by heating at 90°C for 5 minutes, followed by heating at 130°C for 5 minutes, forming a stage B adhesive film (thickness: 50 μm) on the support film.

[0053] 2. Evaluation (1) Viscoelasticity of the membrane Eight adhesive films of specified dimensions were cut from the adhesive film. They were laminated onto a hot plate at 70°C using rubber rollers to prepare a laminate with a thickness of 400 μm. The laminate was then punched with a φ9 mm punch to create a sample. The sample was mounted on the measuring fixture of a rotary viscoelasticity measuring device (manufactured by TA Instruments Japan Inc., trade name: ARES-RDA). The gap of the measuring fixture was adjusted so that the load applied to the sample at that point was 10-15 g. Next, the viscoelasticity of the sample was measured under the following conditions. Figure 7 is a graph showing the relationship between the shear viscosity (complex viscosity) of the adhesive films of Examples 1-3 and the comparative example and temperature. Figure 8 is a graph showing the relationship between the tanδ of the adhesive films of Examples 1-3 and the comparative example and temperature. The minimum melt viscosity and the maximum tanδ within the range of 90-180°C were read from the measurement results. The minimum melt viscosity is the minimum value of the shear viscosity (complex viscosity) within the range of 90-180°C. Measurement conditions: Plate: Aluminum, round (8mm φ) Measurement frequency: 1Hz Heating rate: 5℃ / minute Strain: 5% Temperature measurement: 35~180℃ Initial load: 100g

[0054] (2) Deformation of the membrane Figure 9 is a schematic cross-sectional view of an evaluation adhesive used to evaluate the deformation of the adhesive film accompanying curing. A first semiconductor wafer T1 (thickness: 60 μm) having dimensions of 3 mm × 2 mm and four spacers 3 (thickness: 100 μm) surrounding the first semiconductor wafer T1 are disposed on a substrate 1. The first semiconductor wafer T1 and the spacers 3 are attached to the substrate 1 via a first adhesive film 11 (thickness: 20 μm). The height difference between the spacers 3 on the substrate 1 and the first semiconductor wafer T1 is 40 μm. The spacing between the first semiconductor wafer T1 and each spacer 3 is 1.5 mm on the short side of the first semiconductor wafer T1 and 1.0 mm on the long side of the first semiconductor wafer T1.

[0055] A second semiconductor wafer T2 with dimensions of 12mm × 6mm and a second adhesive film 12 attached thereto were prepared. The adhesive films prepared in "1. Fabrication of the Adhesive Film" were used as the second adhesive film 12. The prepared adhesive-coated wafer was pressed onto a spacer 3 to cover the first semiconductor wafer T1. The formed structure was heated in an oven at a maximum temperature of 140°C to cure the second adhesive film 12. Afterwards, the structure was observed using an ultrasonic digital imaging diagnostic system (manufactured by Insight CO., LTD., IS-350 or IS-450) with an ultrasonic microscope (SAM). Cases where no black shadow was observed were evaluated as "OK," and cases where a black shadow was observed were evaluated as "NG." A black shadow is caused by deformation of the adhesive film 12; if no such black shadow is observed, the adhesive film is considered to have good embedding properties. The SAM conditions are as follows. • Reflection method • Frequency: 75MHz • Focal distance: 9mm Furthermore, the structure was cut in half, and the adhesive film 12 inside the cross-section was observed using an optical microscope. The minimum thickness t of the second adhesive film 12 was measured.

[0056] Table 1 shows the evaluation results. It was confirmed that the adhesive films of Examples 1-5 can suppress localized thickness shrinkage accompanying curing. The adhesive film of the comparative example deformed significantly in the thickness direction near the end of the first semiconductor wafer T1 due to curing; as a result, a portion with a thickness of 0 μm was observed, i.e., the portion where the adhesive film 12 essentially disappeared. The adhesive films of Examples 1-5 also exhibited excellent embedding properties.

[0057] Table 1 Example 1 Example 2 Example 3 Example 4 Example 5 Comparative example Epoxy resin N-500P-10 10.4 9.4 8.7 9.2 9.7 10.4 EXA-830CRP 13.0 11.2 10.9 11.5 12.1 13.0 curing agent MEH-7800M 19.2 16.1 16.0 16.9 17.8 19.2 Inorganic packing SC2050-HLG 39.1 45.0 44.0 42.0 40.0 39.1 elastomer SG-P3 18.0 18.0 20.0 20.0 20.0 18.0 Silane coupling agent Z-6119 0.18 0.18 0.18 0.09 0.09 0.18 A-189 0.09 0.09 0.09 0.18 0.18 0.09 imidazole compounds 2PZ-CN 0.12 0.12 0.05 0.05 0.06 0.06 Minimum melt viscosity [Pa·s] 3920 5030 4880 4550 4300 1560 tanδ maximum value 0.63 0.66 0.70 0.60 0.59 1.23 Then the membrane deforms Minimum thickness [μm] 33 32 30 25 twenty three 0 SAM OK OK OK OK OK NG

[0058] 1:Substrate 3: Spacer 11, 12, 13: Adhesive membrane 15: Structure 20: Substrate (cutting film) 30: Protective film 50: Stacked film (grain-cut bonding film) 60: Sealing layer 100: Semiconductor devices T1: First Semiconductor Wafer T2: Second semiconductor chip w: wire

Claims

1. A thermosetting semiconductor adhesive film for bonding a semiconductor wafer to an adhesive substrate while embedding wires for connection with other semiconductor wafers, the adhesive film exhibiting a maximum tanδ of less than 1.0 and a minimum melt viscosity of more than 2500 Pa·s and less than 10000 Pa·s in the temperature range of 90 to 180°C, the aforementioned maximum tanδ and the aforementioned minimum melt viscosity being obtained by measuring the dynamic viscoelasticity of the adhesive film in the temperature range of 90 to 180°C at a heating rate of 5°C / min and a frequency of 1 Hz, the adhesive film comprising a thermosetting resin containing epoxy resin, a curing agent, an imidazole compound and an inorganic filler, wherein the content of the aforementioned inorganic filler is 10 to 60% by mass based on the mass of the adhesive film.

2. The semiconductor adhesive film as claimed in claim 1, wherein the content of the aforementioned imidazole compound is 0.30 to 5.0 parts by mass relative to 100 parts by mass of the aforementioned epoxy resin.

3. The semiconductor adhesive film as described in claim 1, wherein the content of the aforementioned inorganic filler is 35 to 50% by mass, based on the mass of the adhesive film.

4. The semiconductor adhesive film as claimed in claim 1, wherein the adhesive film contains an elastomer, and the content of the elastomer is 15 to 30% by mass based on the mass of the adhesive film.

5. The semiconductor adhesive film as described in claim 4, wherein the aforementioned elastomer contains an acrylic resin.

6. The semiconductor adhesive film as claimed in claim 1, wherein the adhesive film has a thickness of 25 to 80 μm.

7. The semiconductor adhesive film as claimed in claim 1, wherein the adhesive film contains an elastomer, and the content of the aforementioned inorganic filler is 35-50% by mass based on the mass of the adhesive film, and the content of the aforementioned elastomer is 15-30% by mass based on the mass of the adhesive film.

8. The semiconductor adhesive film as described in claim 7, wherein the aforementioned elastomer contains an acrylic resin.

9. A die-cutting bonding film comprising: a dicing film; and a semiconductor bonding film as described in claim 1 disposed on the aforementioned dicing film.

10. A method of manufacturing a semiconductor device, comprising the steps of: placing a second semiconductor wafer and an adhesive film on a structure having a substrate and a first semiconductor wafer mounted on the substrate, wherein the adhesive film is disposed between the structure and the second semiconductor wafer; and thermally curing the adhesive film to attach the second semiconductor wafer to the structure, wherein the adhesive film is the semiconductor adhesive film described in claim 1, and a conductive wire is connected to the first semiconductor wafer, wherein a portion or all of the conductive wire is embedded by the adhesive film.

11. The method of claim 10, wherein the aforementioned structure further comprises a spacer disposed on the aforementioned substrate and around the aforementioned first semiconductor wafer, the aforementioned second semiconductor wafer and the aforementioned adhesive film being disposed on the aforementioned structure such that the aforementioned adhesive film is disposed between the aforementioned spacer and the aforementioned second semiconductor wafer.

12. The method as described in claim 11, wherein the adhesive film is thermally cured in such a manner that the adhesive film contacts the first semiconductor wafer.

13. The method as claimed in claim 10, wherein the method further comprises the step of forming a sealing layer that seals the aforementioned first semiconductor wafer and the aforementioned second semiconductor wafer.

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