Semiconductor device manufacturing method, adhesive layer, and dicing / die bonding integrated film

Abstract

To provide a method for manufacturing a semiconductor device where a plurality of semiconductor elements are stacked, which prevents peeling between the adjacent semiconductor elements.SOLUTION: A method for manufacturing a semiconductor device includes the steps of: preparing a dicing-die bonding integrated film having an adhesive layer composed of a thermosetting resin composition having melt viscosity at 120°C of 3,100 Pa s or more, a sticking layer and a base material film; sticking the surface on the adhesive layer of the dicing-die bonding integrated film, and a semiconductor wafer; dicing the semiconductor wafer; expanding the base material film, and thereby obtaining a semiconductor element with an adhesive; picking up the semiconductor element with the adhesive from the sticking layer; stacking the semiconductor element to other semiconductor element through the adhesive; and thermosetting the adhesive.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a method for manufacturing a semiconductor device, a thermosetting resin composition, and a dicing-die bonding integrated film. [Background technology]

[0002] A semiconductor device is manufactured through the following steps: First, a semiconductor wafer is fixed with a dicing adhesive sheet, and then the semiconductor wafer is divided into individual semiconductor chips. Then, an expanding step, a pick-up step, a die bonding step, a reflow step, and a die bonding step are performed.

[0003] One of the important characteristics required for semiconductor devices is connection reliability. To improve connection reliability, film-like adhesives for die bonding have been developed that take into account properties such as heat resistance, moisture resistance, and reflow resistance. For example, Patent Document 1 discloses an adhesive sheet containing a resin including a high-molecular-weight component and a thermosetting component mainly composed of an epoxy resin, and a filler. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-190964 Summary of the Invention [Problem to be solved by the invention]

[0005] The present inventors are developing a thermosetting adhesive for use in the manufacturing process of semiconductor devices (e.g., 3D NAND type memories) that have high capacity due to the stacking of semiconductor elements in multiple layers. 3D NAND wafers consist of complex circuit layers and relatively thin semiconductor layers (e.g., about 15 to 25 μm), and therefore, the semiconductor elements obtained by dicing these wafers have the problem of being prone to warping.

[0006] Figure 5(a) is a cross-sectional view that schematically shows a structure during the manufacturing process of a semiconductor device. The structure 30 shown in Figure 5(a) includes a substrate 10 and four semiconductor elements S1, S2, S3, and S4 stacked on the substrate 10. The four semiconductor elements S1, S2, S3, and S4 are stacked at positions that are shifted from one another in the horizontal direction (a direction perpendicular to the stacking direction) for connection with electrodes (not shown) formed on the surface of the substrate 10 (see Figure 1). The semiconductor element S1 is adhered to the substrate 10 with an adhesive, and adhesive is also interposed between the three semiconductor elements S2, S3, and S4.

[0007] According to the inventors' investigations, when the semiconductor elements S1, S2, S3, and S4 each have a complex circuit layer (upper surface side) and a relatively thin semiconductor layer (lower surface side), peeling is likely to occur between the first-layer semiconductor element S1 and the second-layer semiconductor element S2, as shown in Figure 5(b). The inventors speculate on the cause of this as follows. As described above, due to the complex circuit layers and thin semiconductor layers, the semiconductor elements S1, S2, S3, and S4 have a tendency to warp (warping stress). The overhang portion H is formed by stacking multiple semiconductor elements with their positions shifted laterally. Since it has been confirmed that peeling will not occur when the second-stage semiconductor element S2 is mounted, mounting the third-stage and fourth-stage semiconductor elements S3 and S4 increases the upward force on the hangover portion H of the second-stage semiconductor element S2 (warping stress in the direction that causes peeling between it and the first-stage semiconductor element S1).

[0008] The present disclosure has been made in view of the above-mentioned problems, and provides a method for manufacturing a semiconductor device in which a plurality of semiconductor elements are stacked and peeling between adjacent semiconductor elements is unlikely to occur. The present disclosure also provides a thermosetting resin composition and a dicing / die bonding integrated film applicable to the manufacturing method. [Means for solving the problem]

[0009] One aspect of the present disclosure provides a method for manufacturing a semiconductor device (e.g., a three-dimensional NAND memory) in which multiple semiconductor elements are stacked. This manufacturing method includes the steps of preparing an integrated dicing and die bonding film having, in this order, an adhesive layer, a pressure-sensitive adhesive layer, and a base film, each made of a thermosetting resin composition having a melt viscosity of 3100 Pa·s or greater at 120°C, bonding the adhesive layer side of the integrated dicing and die bonding film to a semiconductor wafer, dicing the semiconductor wafer, expanding the base film to obtain adhesive-attached semiconductor elements formed by dividing the semiconductor wafer and the adhesive layer, picking up the adhesive-attached semiconductor elements from the pressure-sensitive adhesive layer, stacking the adhesive-attached semiconductor elements against other semiconductor elements via the adhesive of the adhesive-attached semiconductor elements, and thermally curing the film-like adhesive.

[0010] By using a thermosetting resin composition with a melt viscosity of 3100 Pa·s or more at 120°C, it is possible to achieve an interfacial adhesive strength that can withstand even relatively strong warpage stress of the semiconductor elements to be bonded. This makes it possible to sufficiently prevent delamination between adjacent semiconductor elements, even when multiple semiconductor elements are stacked.

[0011] In order to obtain semiconductor elements by dicing a relatively thin semiconductor wafer, such as a semiconductor wafer for three-dimensional NAND, it is preferable to expand the base film under cooled conditions (for example, −15°C to 0°C) after stealth dicing or blade dicing the semiconductor wafer, from the viewpoint of high yield, etc.

[0012] One aspect of the present disclosure provides a thermosetting resin composition for use in a manufacturing process of a semiconductor device, the thermosetting resin composition having a melt viscosity of 3100 Pa s or more at 120° C. This thermosetting resin composition is applicable to the manufacturing method of the semiconductor device.

[0013] The thermosetting resin composition contains a thermosetting resin, a high-molecular-weight component (e.g., an acrylic resin) having a molecular weight of 100,000 to 1,000,000, and a filler, and the content of the high-molecular-weight component is preferably 15 to 50 mass% and the content of the filler is preferably 25 to 45 mass% based on the total mass of the thermosetting resin composition. By setting the contents of the high-molecular-weight component and the filler within the above ranges, adhesive-attached semiconductor elements can be produced more efficiently and stably by expanding and picking up under cooling conditions after stealth dicing or blade dicing the semiconductor wafer.

[0014] The present disclosure provides an integrated dicing and die bonding film comprising an adhesive layer and an adhesive layer made of the above-mentioned thermosetting resin composition. This integrated film is applicable to the above-mentioned semiconductor device manufacturing method. From the viewpoints of cost and adhesive strength, the thickness of the adhesive layer is, for example, 3 to 40 μm. [Effects of the Invention]

[0015] The present disclosure provides a method for manufacturing a semiconductor device in which a plurality of semiconductor elements are stacked, in which peeling between adjacent semiconductor elements is unlikely to occur, and a thermosetting resin composition and a dicing / die bonding integrated film applicable to the manufacturing method. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a cross-sectional view schematically showing an example of a semiconductor device. [Figure 2] FIG. 2 is a cross-sectional view that schematically shows an example of an adhesive-attached semiconductor element that is made up of a film-like adhesive and a semiconductor element. [Figure 3] 3(a) to 3(f) are cross-sectional views that schematically show the process of manufacturing an adhesive-attached semiconductor element. [Figure 4] 4A to 4C are cross-sectional views schematically showing the process of manufacturing the semiconductor device shown in FIG. [Figure 5]Figure 5(a) is a cross-sectional view showing a schematic diagram of the manufacturing process of the semiconductor device shown in Figure 1, and Figure 5(b) is a cross-sectional view showing a structure in which peeling has occurred between the first-stage semiconductor element and the second-stage semiconductor element. [Figure 6] 6A to 6C are cross-sectional views schematically showing the process of manufacturing the semiconductor device shown in FIG. [Figure 7] FIG. 7 is a cross-sectional view schematically showing another example of a semiconductor device. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the following description, identical or equivalent parts will be denoted by the same reference numerals, and duplicated explanations will be omitted. Furthermore, unless otherwise specified, positional relationships such as up, down, left, and right will be based on the positional relationships shown in the drawings. Furthermore, the dimensional ratios of the drawings are not limited to those shown. In this specification, the term "(meth)acrylic" means "acrylic" and its corresponding "methacrylic".

[0018] <Semiconductor device> 1 is a cross-sectional view schematically illustrating a semiconductor device according to this embodiment. The semiconductor device 100 shown in this figure includes a substrate 10, four semiconductor elements S1, S2, S3, and S4 stacked on the surface of the substrate 10, wires W1, W2, W3, and W4 that electrically connect electrodes (not shown) on the surface of the substrate 10 to the four semiconductor elements S1, S2, S3, and S4, and a sealing layer 50 that seals them all together.

[0019] The substrate 10 is, for example, an organic substrate, or may be a metal substrate such as a lead frame. From the viewpoint of suppressing warpage of the semiconductor device 100, the thickness of the substrate 10 is, for example, 90 to 180 μm, or may be 90 to 140 μm.

[0020] The four semiconductor elements S1, S2, S3, and S4 are stacked via a cured product 3 of a film-like adhesive 3P (see FIG. 2). The shape of the semiconductor elements S1, S2, S3, and S4 in plan view is, for example, rectangular (square or oblong). The length of one side of the semiconductor elements S1, S2, S3, and S4 is, for example, 5 mm or less, and may be 2 to 4 mm or 1 to 4 mm. The thickness of the semiconductor elements S1, S2, S3, and S4 is, for example, 10 to 170 μm, and may be 10 to 30 μm. The lengths of one side of the four semiconductor elements S1, S2, S3, and S4 may be the same or different from each other, and the same applies to the thicknesses.

[0021] <Semiconductor element with adhesive> FIG. 2 is a cross-sectional view showing a schematic example of an adhesive-attached semiconductor element. The adhesive-attached semiconductor element 20 shown in FIG. 2 is composed of a film-like adhesive 3P and a semiconductor element S1. As shown in FIG. 2, the film-like adhesive 3P and the semiconductor element S1 are substantially the same size. The same applies to the film-like adhesive 3P and the semiconductor elements S2, S3, and S4. The adhesive-attached semiconductor element 20 is produced through a dicing process and a pick-up process, as will be described next.

[0022] An example of a method for producing an adhesive-attached semiconductor element 20 (a laminate of a film-like adhesive 3P and a semiconductor element S1) shown in FIG. 2 will be described with reference to FIGS. 3(a) to 3(f). First, an integrated dicing and die bonding film 8 (hereinafter sometimes referred to as "film 8") is prepared and placed in a predetermined device (not shown). The film 8 comprises a base film 1, an adhesive layer 2, and an adhesive layer 3A, in this order. The base film 1 is, for example, a polyethylene terephthalate film (PET film). The semiconductor wafer W is, for example, a thin semiconductor wafer having a thickness of 10 to 100 μm. The semiconductor wafer W may be made of single crystal silicon, polycrystalline silicon, various ceramics, or a compound semiconductor such as gallium arsenide.

[0023] The adhesive layer 3A is made of a thermosetting resin composition as described below. The thickness of the adhesive layer 3A is, for example, 3 to 40 μm, or may be 3 to 30 μm or 3 to 25 μm, from the viewpoints of cost and adhesive strength of the cured product.

[0024] As shown in Figures 3(a) and 3(b), a film 8 is attached to one surface of a semiconductor wafer W so that the adhesive layer 3A is in contact with the surface. This step is preferably carried out at a temperature of 50 to 100°C, more preferably 60 to 80°C. If the temperature is 50°C or higher, good adhesion between the semiconductor wafer W and the adhesive layer 3A can be obtained, and if the temperature is 100°C or lower, excessive flow of the adhesive layer 3A during this step is suppressed.

[0025] As shown in FIG. 3(c), modified regions R are formed in the semiconductor wafer W by irradiating the semiconductor wafer W with laser light along the intended cutting line (stealth dicing). Instead of stealth dicing, cuts may be made in the semiconductor wafer by blade dicing. Note that the semiconductor wafer W may be thinned by grinding it prior to irradiating the semiconductor wafer W with laser light or blade dicing.

[0026] As shown in FIG. 3(d), the semiconductor wafer W is divided at the modified region R by expanding the base film 1 at room temperature or under cooled conditions. This separates the semiconductor wafer W into multiple semiconductor elements S1, and the adhesive layer 3A into film-like adhesives 3P. If the adhesive layer 2 is UV-curable, for example, as shown in FIG. 3(e), the adhesive-bonded semiconductor elements 20 are separated from each other by expanding the adhesive layer 2. This hardens the adhesive layer 2 by irradiating it with ultraviolet light, thereby reducing the adhesive strength between the adhesive layer 2 and the adhesive layer 3A. After UV irradiation, the adhesive-bonded semiconductor elements 20 are pushed up by a needle 42 to peel them from the adhesive layer 2, and then the adhesive-bonded semiconductor elements 20 are picked up by suction with a suction collet 44 (see FIG. 3(f)). In this manner, the adhesive-bonded semiconductor elements 20 shown in FIG. 2 are obtained.

[0027] From the viewpoint of suitably dividing the adhesive layer 3A to obtain a film-like adhesive 3P of a predetermined shape and size, the base film 1 is preferably expanded under cooling conditions. This temperature condition may be, for example, -15 to 0°C.

[0028] <Method of manufacturing a semiconductor device> A method for manufacturing the semiconductor device 100 will be described with reference to FIGS. 4 to 6. First, as shown in FIG. 4, the first-stage semiconductor element S1 is pressure-bonded onto the surface of the substrate 10. That is, the semiconductor element S1 is pressure-bonded to a predetermined position on the substrate 10 via the film-like adhesive 3P of the adhesive-attached semiconductor element 20. This pressure-bonding process is preferably carried out, for example, at 80 to 180°C and 0.01 to 0.50 MPa for 0.5 to 3.0 seconds. Next, the film-like adhesive 3P is cured by heating. This curing process is preferably carried out, for example, at 60 to 175°C and 0.01 to 1.0 MPa for 5 minutes or more. This cures the film-like adhesive 3P to form a cured product 3. The curing process of the film-like adhesive 3P may be carried out in a pressurized atmosphere to reduce voids.

[0029] In the same manner as mounting the semiconductor element S1 on the substrate 10, the second-stage semiconductor element S2 is mounted on the surface of the semiconductor element S1. Furthermore, by mounting the third-stage and fourth-stage semiconductor elements S3 and S4, the structure 30 shown in Fig. 5(a) is produced. After electrically connecting the semiconductor elements S1, S2, S3, and S4 to the substrate 10 with wires W1, W2, W3, and W4 (see Fig. 5), the semiconductor elements and wires are encapsulated with an encapsulation layer 50, thereby completing the semiconductor device 100 shown in Fig. 1.

[0030] <Thermosetting resin composition> The thermosetting resin composition that constitutes the film-like adhesive 3P will now be described. The film-like adhesive 3P is formed by cutting the adhesive layer 3A into individual pieces, and both are made of the same thermosetting resin composition. This thermosetting resin composition can, for example, go through a semi-cured (B-stage) state and then become a fully cured (C-stage) state through a subsequent curing treatment.

[0031] The thermosetting resin composition has a melt viscosity of 3100 Pa·s or more at 120°C. By using the thermosetting resin composition, it is possible to achieve an interfacial adhesive strength that can withstand even relatively strong warpage stress of the semiconductor element to be bonded. This allows for sufficient prevention of delamination between adjacent semiconductor elements, even when multiple semiconductor elements are stacked. The melt viscosity of the thermosetting resin composition at 120°C may be 3100 to 40,000 Pa·s or 5,000 to 35,000 Pa·s. The lower limit of this melt viscosity may be 13,000 Pa·s or 14,000 Pa·s. The melt viscosity refers to a measurement value measured by using an ARES (manufactured by TA Instruments) to mold a thermosetting resin composition into a film, applying a 5% strain and increasing the temperature at a heating rate of 5°C / min.

[0032] The thermosetting resin composition (before curing treatment) has, for example, a storage modulus of 70 MPa or more at 35°C. By using such a thermosetting resin composition, it is possible to achieve a cohesive strength that can withstand even relatively strong warpage stress of the semiconductor elements to be bonded. This makes it possible to sufficiently prevent peeling between adjacent semiconductor elements even when multiple semiconductor elements are stacked. The storage modulus of the thermosetting resin composition at 35°C may be 70 to 1000 MPa, or may be 80 to 900 MPa. The storage modulus refers to a value obtained by measurement using the following equipment and conditions. Dynamic viscoelasticity measuring device: Rheogel E-4000 (manufactured by UBM Corporation) Measurement object: Thermosetting resin composition molded into film Heating rate: 3°C / min Frequency: 10Hz

[0033] The thermosetting resin composition preferably contains the following components: (a) Thermosetting resin (hereinafter, sometimes simply referred to as "component (a)") (b) High molecular weight component (hereinafter sometimes simply referred to as "component (b)") (c) Filler (hereinafter sometimes simply referred to as "component (c)") In this embodiment, when the (a) thermosetting resin contains an epoxy resin (hereinafter, sometimes simply referred to as "component (a1)"), the (a) thermosetting resin preferably contains a phenolic resin (hereinafter, sometimes simply referred to as "component (a2)") that can serve as a curing agent for the epoxy resin. Note that when the (b) high-molecular-weight component has a functional group (such as a glycidyl group) that thermally cures with the phenolic resin, it is not necessary to use a separate epoxy resin as the (a) thermosetting resin.

[0034] The thermosetting resin composition may further include the following components: (d) Coupling agent (hereinafter sometimes simply referred to as "component (d)") (e) Curing accelerator (hereinafter sometimes simply referred to as "component (e)")

[0035] The content of component (a) is, for example, 30% by mass or less, and may be 5 to 30% by mass, based on the total mass of the thermosetting resin composition. The content of component (b) is, for example, 15 to 66% by mass, and may be 15 to 50% by mass, based on the total mass of the thermosetting resin composition. The content of component (c) is, for example, 25 to 50% by mass, and may be 25 to 45% by mass, based on the total mass of the thermosetting resin composition. By setting the contents of components (b) and (c) within the above ranges, adhesive-attached semiconductor elements can be more efficiently and stably produced by expanding and picking up under cooling conditions after stealth dicing or blade dicing a semiconductor wafer.

[0036] Specifically, when the content of component (b) is 66% by mass or less, excellent splitting properties tend to be obtained when expanded under cooling conditions (see Figure 3(d)). Furthermore, when the content of component (b) is 15% by mass or more and the content of component (c) is 50% by mass or less, the bulk strength under cooling conditions is sufficiently high, and the composition is easily split into predetermined shapes and sizes by expanding. The melt viscosity of the thermosetting resin composition at 120°C can be adjusted within the above range by appropriately adjusting the amounts of (a) thermosetting resin, (b) high-molecular-weight component, and (c) filler.

[0037] From the viewpoint of connection reliability, the storage modulus of the cured product (C-stage) of the thermosetting resin composition at 150°C is preferably 10 MPa or more, more preferably 25 MPa or more, and may be 50 MPa or more or 100 MPa or more. The upper limit of the storage modulus is, for example, 600 MPa or may be 500 MPa. The storage modulus of the cured product of the thermosetting resin composition at 150°C can be measured using a dynamic viscoelasticity apparatus, using a sample obtained by curing the thermosetting resin composition at 175°C.

[0038] Each component contained in the thermosetting resin composition will be described below. ·(a) Thermosetting resin The component (a1) can be any epoxy group-containing component without particular limitations. Examples of the component (a1) include bisphenol A epoxy resins, bisphenol F epoxy resins, bisphenol S epoxy resins, phenol novolac epoxy resins, cresol novolac epoxy resins, bisphenol A novolac epoxy resins, bisphenol F novolac epoxy resins, dicyclopentadiene skeleton-containing epoxy resins, stilbene epoxy resins, triazine skeleton-containing epoxy resins, fluorene skeleton-containing epoxy resins, triphenol phenol methane epoxy resins, biphenyl epoxy resins, xylylene epoxy resins, biphenyl aralkyl epoxy resins, naphthalene epoxy resins, polyfunctional phenols, and diglycidyl ether compounds of polycyclic aromatics such as anthracene. These may be used alone or in combination of two or more. Among these, the component (a1) may be a cresol novolac epoxy resin, a bisphenol F epoxy resin, or a bisphenol A epoxy resin from the viewpoint of heat resistance.

[0039] The epoxy equivalent of component (a1) may be 90 to 300 g / eq, 110 to 290 g / eq, or 130 to 280 g / eq. When the epoxy equivalent of component (a1) is within this range, the film adhesive tends to have sufficient flowability while maintaining its bulk strength.

[0040] The content of component (a1) may be 50 parts by mass or less, 5 to 50 parts by mass, 10 to 40 parts by mass, or 20 to 30 parts by mass, relative to 100 parts by mass of the total mass of components (a), (b), and (c). When the content of component (a1) is 5 parts by mass or more, the embeddability of the film-like adhesive tends to be better. When the content of component (a1) is 50 parts by mass or less, the occurrence of bleeding tends to be further suppressed.

[0041] The component (a2) can be any compound having a phenolic hydroxyl group in the molecule. Examples of the component (a2) include novolak-type phenolic resins obtained by condensing or co-condensing phenols such as phenol, cresol, resorcinol, catechol, bisphenol A, bisphenol F, phenylphenol, and aminophenol and / or naphthols such as α-naphthol, β-naphthol, and dihydroxynaphthalene with a compound having an aldehyde group such as formaldehyde under an acidic catalyst; phenol aralkyl resins and naphthol aralkyl resins synthesized from phenols such as allylated bisphenol A, allylated bisphenol F, allylated naphthalenediol, phenol novolak, and / or naphthols with dimethoxyparaxylene or bis(methoxymethyl)biphenyl; and the like. These compounds may be used alone or in combination of two or more. Among these, the component (a2) may be a phenol aralkyl resin, a naphthol aralkyl resin, or a novolac type phenolic resin from the viewpoint of moisture absorption and heat resistance.

[0042] The hydroxyl equivalent of component (a2) may be 80 to 250 g / eq, 90 to 200 g / eq, or 100 to 180 g / eq. When the hydroxyl equivalent of component (a2) is within this range, the adhesive film tends to maintain high adhesive strength while maintaining its fluidity.

[0043] The softening point of the component (a2) may be 50 to 140°C, 55 to 120°C, or 60 to 100°C.

[0044] The content of component (a2) may be 5 to 50 parts by mass, 10 to 40 parts by mass, or 20 to 30 parts by mass, based on 100 parts by mass of the total mass of components (a), (b), and (c). When the content of component (a2) is 5 parts by mass or more, better curing properties tend to be obtained. When the content of component (a2) is 50 parts by mass or less, the embeddability of the film-like adhesive tends to be better.

[0045] From the viewpoint of curability, the ratio of the epoxy equivalent of component (a1) to the hydroxyl equivalent of component (a2) (epoxy equivalent of component (a1) / hydroxyl equivalent of component (a2)) may be 0.30 / 0.70 to 0.70 / 0.30, 0.35 / 0.65 to 0.65 / 0.35, 0.40 / 0.60 to 0.60 / 0.40, or 0.45 / 0.55 to 0.55 / 0.45. When the equivalent ratio is 0.30 / 0.70 or more, more sufficient curability tends to be obtained. When the equivalent ratio is 0.70 / 0.30 or less, excessive viscosity increase can be prevented, and more sufficient fluidity can be obtained.

[0046] ·(b) High molecular weight component The component (b) preferably has a glass transition temperature (Tg) of 50° C. or less. Examples of the component (b) include acrylic resin, polyester resin, polyamide resin, polyimide resin, silicone resin, butadiene resin, acrylonitrile resin, and modified products thereof.

[0047] From the viewpoint of fluidity, component (b) may contain an acrylic resin. Here, the acrylic resin refers to a polymer containing a structural unit derived from a (meth)acrylic acid ester. The acrylic resin is preferably a polymer containing a structural unit derived from a (meth)acrylic acid ester having a crosslinkable functional group such as an epoxy group, an alcoholic or phenolic hydroxyl group, or a carboxyl group as a structural unit. The acrylic resin may also be an acrylic rubber such as a copolymer of a (meth)acrylic acid ester and acrylonitrile.

[0048] The glass transition temperature (Tg) of the acrylic resin may be -50 to 50°C or -30 to 30°C. When the Tg of the acrylic resin is -50°C or higher, it tends to be possible to prevent the flexibility of the adhesive composition from becoming too high. This makes it easier to cut the film-like adhesive during wafer dicing, and makes it possible to prevent the occurrence of burrs. When the Tg of the acrylic resin is 50°C or lower, it tends to be possible to suppress a decrease in the flexibility of the adhesive composition. This tends to make it easier to sufficiently fill voids when the film-like adhesive is attached to a wafer. It also makes it possible to prevent chipping during dicing due to a decrease in wafer adhesion. Here, the glass transition temperature (Tg) refers to a value measured using a DSC (differential scanning calorimeter) (for example, "Thermo Plus 2" manufactured by Rigaku Corporation).

[0049] The weight-average molecular weight (Mw) of the acrylic resin is, for example, 100,000 to 3,000,000, and may be 100,000 to 1,000,000, 100,000 to 800,000, or 300,000 to 2,000,000. When the Mw of the acrylic resin is within this range, it is possible to appropriately control the film-forming properties, film strength, flexibility, tackiness, etc., and it is also possible to achieve excellent reflowability and improved embeddability. Here, Mw refers to a value measured by gel permeation chromatography (GPC) and converted using a calibration curve based on standard polystyrene.

[0050] Commercially available acrylic resins include, for example, SG-70L, SG-708-6, WS-023 EK30, SG-P3, SG-280 EK23, HTR-860P-3CSP, and HTR-860P-3CSP-3DB (all manufactured by Nagase ChemteX Corporation).

[0051] The content of component (b) may be 5 to 70 parts by mass, 10 to 50 parts by mass, or 15 to 30 parts by mass, based on 100 parts by mass of the total mass of components (a), (b), and (c). When the content of component (b) is 5 parts by mass or more, control of flowability during molding and handleability at high temperatures can be further improved. When the content of component (b) is 70 parts by mass or less, embeddability can be further improved.

[0052] (c) Filler Examples of component (c) include inorganic fillers such as 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 silica. These may be used alone or in combination of two or more. Among these, component (c) may be silica from the viewpoint of compatibility with the resin.

[0053] From the viewpoint of improving adhesiveness, the average particle size of component (c) may be 0.005 to 1 μm or 0.05 to 0.5 μm, where the average particle size refers to a value determined by conversion from the BET specific surface area.

[0054] The content of component (c) may be 5 to 50 parts by mass, 15 to 45 parts by mass, or 25 to 40 parts by mass, relative to 100 parts by mass of the total mass of components (a), (b), and (c). When the content of component (c) is 5 parts by mass or more, the fluidity of the film-like adhesive tends to be further improved. When the content of component (c) is 50 parts by mass or less, the dicing properties of the film-like adhesive tend to be better.

[0055] (d) Coupling agent Component (d) may be a silane coupling agent. Examples of silane coupling agents include γ-ureidopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, 3-phenylaminopropyltrimethoxysilane, and 3-(2-aminoethyl)aminopropyltrimethoxysilane. These may be used alone or in combination of two or more.

[0056] The content of the component (d) may be 0.01 to 5 parts by mass relative to 100 parts by mass of the total mass of the components (a), (b), and (c).

[0057] (e) Curing accelerator The component (e) is not particularly limited, and a commonly used component can be used. Examples of the component (e) include imidazoles and their derivatives, organic phosphorus compounds, secondary amines, tertiary amines, and quaternary ammonium salts. These may be used alone or in combination of two or more. Among these, imidazoles and their derivatives may be used as the component (e) from the viewpoint of reactivity.

[0058] Examples of imidazoles include 2-methylimidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, etc. These may be used alone or in combination of two or more.

[0059] The content of the component (e) may be 0.01 to 1 part by mass relative to 100 parts by mass of the total mass of the components (a), (b), and (c).

[0060] <Dicing and die bonding integrated film and its manufacturing method> The dicing-die bonding integrated film 8 shown in Fig. 3(a) and its manufacturing method will be described. The manufacturing method of film 8 includes a step of applying a varnish of an adhesive composition containing a solvent onto a substrate film (not shown) for an adhesive layer, and a step of heating and drying the applied varnish at 50 to 150°C to form an adhesive layer 3A.

[0061] The adhesive composition varnish can be prepared, for example, by mixing or kneading components (a) to (c), and optionally components (d) and (e), in a solvent. Mixing or kneading can be carried out using a conventional dispersing machine such as a mixer, a grinder, a triple-roll mill, or a ball mill, or by appropriately combining these.

[0062] The solvent for preparing the varnish is not limited as long as it can uniformly dissolve, knead, or disperse the above-mentioned components, and conventionally known solvents can be used. Examples of such solvents include ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone, as well as dimethylformamide, dimethylacetamide, N-methylpyrrolidone, toluene, and xylene. Methyl ethyl ketone and cyclohexanone are preferred because they dry quickly and are inexpensive.

[0063] The base film for the adhesive layer is not particularly limited, and examples thereof include polyester film, polypropylene film (such as OPP film), polyethylene terephthalate film, polyimide film, polyetherimide film, polyether naphthalate film, and methylpentene film.

[0064] The method for applying the varnish to the base film can be a known method, such as knife coating, roll coating, spray coating, gravure coating, bar coating, curtain coating, etc. The conditions for heat drying are not particularly limited as long as the solvent used is sufficiently evaporated, and can be, for example, heated at 50 to 150°C for 1 to 30 minutes. Heat drying can also be performed by gradually increasing the temperature within a range of 50 to 150°C. A laminated film of the base film and the adhesive layer 20A can be obtained by volatilizing the solvent contained in the varnish by heat drying.

[0065] The film 8 can be obtained by bonding the laminated film obtained as described above to a dicing film (a laminate of the base film 1 and the adhesive layer 2). Examples of the base film 1 include plastic films such as polytetrafluoroethylene film, polyethylene terephthalate film, polyethylene film, polypropylene film, polymethylpentene film, and polyimide film. The base film 1 may be subjected to surface treatment such as primer application, UV treatment, corona discharge treatment, polishing treatment, and etching treatment, as necessary. The adhesive layer 2 may be UV-curable or pressure-sensitive. The film 8 may further include a protective film (not shown) covering the adhesive layer 2.

[0066] Although the embodiments of the present disclosure have been described in detail above, the present invention is not limited to the above embodiments. For example, in the above embodiments, a package in which four semiconductor elements are stacked is illustrated, but the number of stacked semiconductor elements is not limited to this. Furthermore, in the above embodiments, an embodiment in which multiple semiconductor elements are stacked with their positions shifted in a direction perpendicular to the stacking direction of the semiconductor elements is illustrated, but the semiconductor elements may be stacked without being shifted, as shown in FIG. 7. [Example]

[0067] The present disclosure will be described in more detail below with reference to examples, although the present invention is not limited to the following examples.

[0068] (Examples 1 to 12 and Comparative Examples 1 to 5) Varnishes (17 types in total) containing the components shown in Tables 1 to 4 were prepared as follows. Specifically, cyclohexanone was added to a composition containing an epoxy resin and a phenolic resin as thermosetting resins, and a filler, and the mixture was stirred. After adding an acrylic rubber as a high-molecular-weight component and stirring, a coupling agent and a curing accelerator were further added, and the components were stirred until sufficiently uniform, yielding a varnish.

[0069] The components listed in Tables 1 to 4 are as follows. (epoxy resin) YDCN-700-10: Cresol novolac epoxy resin, manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., epoxy equivalent 210, softening point 75-85°C EXA-830CRP (trade name): Bisphenol F epoxy resin, manufactured by DIC Corporation, epoxy equivalent weight 162, liquid at room temperature YDF-8170C: Bisphenol F epoxy resin, manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., epoxy equivalent weight 159, liquid at room temperature (phenolic resin) Milex XLC-LL (Mirex is a registered trademark): manufactured by Mitsui Chemicals, Inc., hydroxyl equivalent weight 175, softening point 77°C Phenolite LF-4871 ("Phenolite" is a registered trademark): manufactured by DIC Corporation, hydroxyl equivalent weight 118, softening point 130°C (High molecular weight component) HTR-860P: Nagase ChemteX Corporation, acrylic rubber, weight average molecular weight 800,000, Tg -7°C (filler) SC-2050-HLG: Admatechs Co., Ltd., silica filler dispersion, average particle size 0.50 μm, maximum particle size 1.0 μm or less Aerosil R972 (Aerosil is a registered trademark): manufactured by Nippon Aerosil Co., Ltd., silica particles, average particle size 0.016 μm, maximum particle size 1.0 μm or less (coupling agent) A-189: γ-mercaptopropyltrimethoxysilane, manufactured by Momentive Performance Materials Japan, LLC A-1160: γ-ureidopropyltriethoxysilane, manufactured by Momentive Performance Materials Japan, LLC (curing accelerator) Curesol 2PZ-CN (Curesol is a registered trademark): 1-cyanoethyl-2-phenylimidazole, manufactured by Shikoku Chemicals Corporation

[0070] The varnish was filtered through a 500-mesh filter and vacuum degassed. The vacuum degassed varnish was applied to a polyethylene terephthalate (PET) film (thickness: 38 μm) that had been subjected to a release treatment. The applied varnish was heated and dried in two stages: at 90°C for 5 minutes and then at 140°C for 5 minutes. In this way, an adhesive film was obtained comprising a film-like adhesive (thickness: 7 μm) in a B-stage state on a PET film as a base film.

[0071] (Melt viscosity measurement of film adhesive) The melt viscosity of the film adhesive at 120°C was measured using the following method. Specifically, multiple 7-μm-thick film adhesives were laminated to a thickness of approximately 300 μm, and this was then punched out to a 10 mm x 10 mm size to obtain a measurement sample. An 8-mm-diameter circular aluminum plate was set in a dynamic viscoelasticity analyzer (ARES, manufactured by TA Instruments), and the sample was then placed on top of it. Measurements were then taken at 35°C, with a 5% strain applied, while the temperature was raised to 130°C at a rate of 5°C / min, and the melt viscosity value at 120°C was recorded. The results are shown in Tables 1 to 4.

[0072] (Measurement of storage modulus of film adhesive) The storage modulus of the film adhesive at 35°C was measured using a dynamic viscoelasticity measuring device (Rheogel E-4000) manufactured by UBM Corporation. Specifically, multiple 7 μm thick film adhesives were laminated to a thickness of approximately 170 μm, and this was cut into a size of 4 mm wide x 33 mm long to obtain a measurement sample. The sample was placed in a dynamic viscoelasticity measuring device (product name: Rheogel E-4000, manufactured by UBM Corporation), and a tensile load was applied, and measurements were performed at a frequency of 10 Hz and a heating rate of 3°C / min to measure the storage modulus at 35°C. The results are shown in Tables 1 to 4.

[0073] [Evaluation of film adhesive separation] Each film-like adhesive (thickness 120 μm) according to the examples and comparative examples was bonded to a dicing adhesive film (manufactured by Maxell, Ltd.) to produce an integrated dicing and die bonding film.

[0074] As described below, a modified region was formed by irradiating a semiconductor wafer with a laser, and then an expanding process was carried out under low-temperature conditions to evaluate the severability of the film adhesive. Specifically, a semiconductor wafer (silicon wafer, 50 μm thick, 12 inches in outer diameter) was prepared. A dicing / die bonding integrated film was attached to one side of the semiconductor wafer so that the film adhesive was in close contact with the surface. Using a laser dicing machine (Tokyo Seimitsu Co., Ltd., MAHOHDICING MACHINE), stealth dicing was performed on a laminate (semiconductor wafer / film adhesive / adhesive layer / substrate layer) containing the semiconductor wafer. The conditions were as follows: Laser source: Semiconductor laser pumped Nd(YAG laser) Wavelength: 1064nm Laser beam spot cross-sectional area: 3.14×10 -8 cm 2 Oscillation type: Q-switched pulse Repetition frequency: 100kHz Pulse width: 30ns Output: 20μJ / pulse Laser light quality: TEM00 Polarization characteristics: Linear polarization Condenser lens magnification: 50x NA:0.55 Transmittance to laser light wavelength: 60% -Movement speed of the stage on which the semiconductor wafer is placed: 100 mm / sec

[0075] The laminate (semiconductor wafer / adhesive layer / pressure-sensitive adhesive layer / base layer) containing the semiconductor wafer after the modified region formation was fixed to an expanding device. Next, the dicing film (pressure-sensitive adhesive layer / base layer) was expanded under the following conditions to separate the film-like adhesive and the semiconductor wafer. This resulted in an adhesive-attached semiconductor element. Equipment: Disco Corporation DDS2300 (Fully Automatic Die Separator) Cool expansion conditions: Temperature: -15℃, Height: 9mm, Cooling time: 60 seconds Speed: 300mm / sec, Waiting time: 0 sec

[0076] After the expanding process, the adhesive layer was exposed to an illuminance of 70mW / cm from the base layer side. 2 The adhesive-attached semiconductor element was irradiated with ultraviolet light for 3 seconds at 1000 kJ / min. The pickup properties of the adhesive-attached semiconductor element were evaluated using a flexible die bonder DB-730 (product name) manufactured by Renesas East Japan Semiconductor Co., Ltd. The pickup collet used was a Micromechanics RUBBER TIP 13-087E-33 (product name, size: 5 x 5 mm). The ejection pin used was a Micromechanics EJECTOR NEEDLE SEN2-83-05 (product name, diameter: 0.7 mm, tip shape: semicircular with a diameter of 350 μm). Five ejection pins were arranged with a center-to-center spacing of 4.2 mm. The pickup conditions were as follows: Pin thrust speed: 10mm / sec Thrust height: 200μm

[0077] After the stealth dicing process, the presence or absence of uncut semiconductor elements with adhesive was visually observed and evaluated according to the following criteria. The results are shown in Tables 1 to 4. A: There were no uncut semiconductor elements with adhesive. B: There was one or more uncut semiconductor elements with adhesive.

[0078] [Whether or not peeling occurs after four-layer lamination] Using samples (semiconductor elements with adhesive) in which the film-like adhesive had been suitably separated, structures with the same configuration as the structure shown in Figure 5(a) were produced for the Examples and Comparative Examples. After stacking the fourth semiconductor element, the presence or absence of peeling between the first and second layers was visually observed and evaluated according to the following criteria. The results are shown in Tables 1 to 4. A: No peeling occurred in any of the samples. B: Peeling occurred in one or more samples.

[0079] [Reflow resistance evaluation] Of the samples prepared for evaluation of the presence or absence of delamination, those that did not exhibit delamination were used to evaluate reflow resistance using the following method. Four semiconductor elements stacked in layers were encapsulated with a molding encapsulant (manufactured by Hitachi Chemical Co., Ltd., product name "CEL-9750ZHF10") to obtain a package for evaluation. The resin encapsulation conditions were 175°C / 6.7 MPa / 90 seconds, and the curing conditions were 175°C, 5 hours. Twenty of the above packages were prepared and exposed to the JEDEC-specified environment (Level 3, 30°C, 60% RH, 192 hours) to absorb moisture. The moisture-absorbed packages were then passed through an IR reflow oven (260°C, maximum temperature 265°C) three times. Evaluation was performed according to the following criteria. The results are shown in Tables 1 to 4. A: Damage to the package, changes in thickness, peeling at the interface between the film adhesive and the semiconductor element, etc. were not observed in any of the 20 packages. B: Damage to the package, changes in thickness, peeling at the interface between the film adhesive and the semiconductor element, etc. was observed in at least one of the 20 packages.

[0080] [Table 1]

[0081] [Table 2]

[0082] [Table 3]

[0083] [Table 4] [Industrial Applicability]

[0084] The present disclosure provides a method for manufacturing a semiconductor device in which a plurality of semiconductor elements are stacked, in which peeling between adjacent semiconductor elements is unlikely to occur, and a thermosetting resin composition and a dicing / die bonding integrated film applicable to the manufacturing method. [Explanation of symbols]

[0085] 1...base film, 2...adhesive layer, 3...cured film adhesive, 3A...adhesive layer, 3P...film adhesive, 8...dicing / die bonding integrated film, 20...semiconductor element with adhesive, 100...semiconductor device, W...semiconductor wafer

Claims

1. a step of preparing an integrated dicing and die bonding film including, in this order, an adhesive layer made of a thermosetting resin composition having a storage modulus at 35°C of 70 MPa or more and 1000 MPa or less, a pressure-sensitive adhesive layer, and a base film; a step of bonding a surface of the dicing and die bonding integrated film on the adhesive layer side to a semiconductor wafer; stealth dicing the semiconductor wafer; a step of expanding the base film under a cooling condition to obtain an adhesive-attached semiconductor element in which the semiconductor wafer and the adhesive layer are singulated; picking up the adhesive-attached semiconductor element from the adhesive layer; a step of stacking the adhesive-attached semiconductor element on another semiconductor element via the adhesive of the adhesive-attached semiconductor element; thermally curing the adhesive; Including, The thermosetting resin composition contains a thermosetting resin and a high-molecular-weight component having a molecular weight of 100,000 to 1,000,000, a content of the high molecular weight component of the thermosetting resin composition of 15 to 66 mass % based on the total mass of the thermosetting resin composition, and a storage modulus at 150°C of a cured product of the thermosetting resin composition of 10 MPa or more.

2. 2. The method for manufacturing a semiconductor device according to claim 1, wherein the adhesive layer has a thickness of 3 to 40 μm.

3. 3. The method for manufacturing a semiconductor device according to claim 1, wherein the content of the high molecular weight component is 15 to 50 mass % based on the total mass of the thermosetting resin composition.

4. 4. The method for manufacturing a semiconductor device according to claim 1, wherein the thermosetting resin composition contains a filler, and the content of the filler is 45 mass% or less, based on the total mass of the thermosetting resin composition.

5. 5. The method for manufacturing a semiconductor device according to claim 1, which is a method for manufacturing a three-dimensional NAND memory.

6. A method for manufacturing a semiconductor device described in any one of claims 1 to 5, except when the thermosetting resin composition comprises an adhesive composition containing (A) a high molecular weight component having a crosslinkable functional group, (B) a multifunctional epoxy resin, (C) a phenolic resin, and (D) inorganic fine particles, and is fully cured at 120°C for 2 hours.

7. An adhesive layer made of a thermosetting resin composition used in a manufacturing process of a semiconductor device, The storage modulus of the thermosetting resin composition at 35°C is 70 MPa or more and 1000 MPa or less, The thermosetting resin composition contains a thermosetting resin and a high-molecular-weight component having a molecular weight of 100,000 to 1,000,000, an adhesive layer, wherein the content of the high molecular weight component is 15 to 66 mass % based on the total mass of the thermosetting resin composition, and the storage modulus of a cured product of the thermosetting resin composition at 150°C is 10 MPa or more.

8. The adhesive layer according to claim 7, having a thickness of 3 to 40 μm.

9. The adhesive layer according to claim 7 or 8, wherein the content of the high molecular weight component is 15 to 50 mass% based on the total mass of the thermosetting resin composition.

10. The thermosetting resin composition contains a filler, and the content of the filler is 45 mass% or less, based on the total mass of the thermosetting resin composition. The adhesive layer according to any one of claims 7 to 9.

11. The adhesive layer according to any one of claims 7 to 10, which is used in a manufacturing process of a three-dimensional NAND memory.

12. The adhesive layer according to any one of claims 7 to 10, except for cases where the thermosetting resin composition comprises an adhesive composition containing (A) a high molecular weight component having a crosslinkable functional group, (B) a polyfunctional epoxy resin, (C) a phenolic resin, and (D) inorganic fine particles, and is fully cured at 120 ° C. for 2 hours.

13. An adhesive layer; The adhesive layer according to any one of claims 7 to 12, This is a dicing and die bonding integrated film.

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