Electromagnetic shielding sheet, shielded wafer, semiconductor device, and method for manufacturing the same.

Abstract

The present invention provides a highly reliable electromagnetic shielding sheet that can be applied to a wafer in a single piece before it is separated into individual pieces and has excellent coverage, as well as a shielded wafer formed using the electromagnetic shielding sheet, a semiconductor device, and a method for manufacturing the same. [Solution] The problem is solved by an electromagnetic wave shielding sheet 3 for collectively covering a semiconductor wafer before individualization, wherein the electromagnetic wave shielding sheet 3 comprises at least a shielding film 30 containing a conductive filler (F) and a binder component, has an elongation rate of 100 to 1500% at 100°C, and the cured sheet obtained after treating the electromagnetic wave shielding sheet 3 at 180°C for 2 hours has a Young's modulus of 100 to 1000 MPa at 100°C.

Description

[Technical Field]

[0001] This disclosure relates to electromagnetic shielding sheets, shielded wafers, and semiconductor devices and methods for manufacturing the same. [Background technology]

[0002] To prevent malfunctions in semiconductor components integrated inside electronic devices such as mobile terminals, technologies are needed to shield against electromagnetic noise generated by the semiconductor components and electromagnetic noise from external sources. Patent Document 1 discloses a method for manufacturing a mounting structure, which includes the steps of preparing a mounting member on which a plurality of second circuit members are mounted on a first circuit member, forming a first hardened layer to cover the mounting member, and forming a functional layer such as a shield cover layer on the first hardened layer by a vapor phase method and / or a plating method. Patent Document 2 discloses an electromagnetic shielding support substrate with a sealing material, which comprises an electromagnetic shielding support substrate and a sealing material laminated on the support substrate. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] International Publication No. 2019 / 117259 [Patent Document 2] Japanese Patent Publication No. 2016-092275 [Overview of the project] [Problems that the invention aims to solve]

[0004] In response to the trend towards miniaturization and reduction of electronic devices, high-density mounting is required for semiconductor packages to also achieve miniaturization and weight reduction. For this reason, wafer-level chip-size packaging (WL-CSP) technology, which packages semiconductor elements formed on wafers by forming external terminals and sealing resin at the stage before wafer fragmentation without using bonding wires for internal wiring, is attracting attention. Providing an electromagnetic shielding sheet that can cover such wafers in one piece and also cover the sides of semiconductor devices after fragmentation would offer significant advantages in terms of versatility, cost-effectiveness, and mass production.

[0005] This disclosure is made in view of the above background and aims to provide a highly reliable electromagnetic wave shielding sheet that can be applied to a semiconductor wafer before it is separated into individual pieces and has excellent coverage, as well as a shielded wafer formed using the electromagnetic wave shielding sheet, a semiconductor device, and a method for manufacturing the same. [Means for solving the problem]

[0006] After diligent research by the present inventors, we have found that the problems of this disclosure can be solved in the following embodiments, and have completed this disclosure. [1]: An electromagnetic shielding sheet for covering at least one of the main surfaces of a semiconductor wafer before pulverization, which has half-cut grooves formed in a grid pattern and element formation regions partitioned by the half-cut grooves and arranged in a matrix pattern, The electromagnetic wave shielding sheet comprises at least a shielding film containing a binder component and a conductive filler (F), The electromagnetic shielding sheet has an elongation rate of 100 to 1500% at 100°C. An electromagnetic wave shielding sheet wherein the cured sheet, after being treated at 180°C for 2 hours, has a Young's modulus of 100 to 1000 MPa at 100°C. [2]: The electromagnetic shielding sheet described in [1], wherein the electromagnetic shielding sheet is heat-pressed onto the entire main surface of a silicon bare wafer at 120°C and 5 MPa for 3 minutes, followed by treatment at 180°C for 2 hours, and the peel rate in an adhesion test after a pressure cooker test based on JIS K5600-5-6 is performed on the shield cover layer derived from the electromagnetic shielding sheet, and the peel rate is less than 15%. [3]: The electromagnetic shielding sheet according to [1] or [2], wherein the binder component comprises a curable compound (C) having a weight-average molecular weight of 5,000 or less and a high molecular weight resin (P) having a weight-average molecular weight of 10,000 or more. [4]: An electromagnetic shielding sheet according to any of [1] to [3], wherein the conductive filler (F) content is 45 to 85% by mass. [5]: Average specific surface area of ​​conductive filler (F) [m 2 The product of [g] 2 An electromagnetic shielding sheet as described in any of [1] to [4]. [6]: The electromagnetic wave shielding sheet according to any one of [1] to [5], wherein the curable compound (C) contains an epoxy group-containing compound (E) having a weight-average molecular weight of 5,000 or less, the epoxy equivalent of the epoxy group-containing compound (E) is 110 to 1,000 g / eq, and the epoxy group-containing compound (E) is present in an amount of 10 to 80 parts by mass per 100 parts by mass of the high molecular weight resin (P). [7]: An electromagnetic shielding sheet according to any one of [1] to [6], wherein the electromagnetic shielding sheet is heat-pressed onto the entire main surface of a 12-inch silicon bare wafer, which has half-cut grooves 200 μm wide and 200 μm deep formed in a grid pattern at 4000 μm intervals, and a shield cover layer derived from the electromagnetic shielding sheet is formed after being treated at 180°C for 2 hours, and the resistance between the shield cover layers covering adjacent protrusions via the half-cut grooves is 5 to 300 mΩ. [8]: A shielded wafer having a shield cover layer formed on at least one main surface of a semiconductor wafer before fragmentation, which is made of an electromagnetic shielding sheet according to any of [1] to [7]. [9]: A semiconductor device in which the shield-processed wafer described in [8] is singulated in units of element formation regions.

[10] : In a semiconductor wafer before singulation having element formation regions formed in a matrix along scribe lines, a step of forming half-cut grooves, A step of disposing the electromagnetic wave shield sheet according to any one of [1] to [7] above the semiconductor wafer, A step of thermocompression bonding the electromagnetic wave shield sheet to the semiconductor wafer, A step of obtaining a shield cover layer by heating and curing the electromagnetic wave shield sheet, A method for manufacturing a semiconductor device, including a step of singulating in units of the element formation regions.

Effect of the Invention

[0007] According to the present disclosure, there is an excellent effect that an electromagnetic wave shield sheet with high reliability and excellent coating property that can be collectively coated on a semiconductor wafer before singulation, a shield-processed wafer, a semiconductor device, and a method for manufacturing the same can be provided.

Brief Description of the Drawings

[0008] [Figure 1] A schematic explanatory view showing an example of a wafer according to an embodiment. [Figure 2] A cross-sectional view taken along the line II-II of FIG. 1. [Figure 3] A partially enlarged view of FIG. 2. [Figure 4] A schematic cross-sectional view showing an example of a wafer with shield processing according to Modification 1. [Figure 5] A schematic cross-sectional view showing an example of a wafer with shield processing according to Modification 2. [Figure 6] A schematic cross-sectional view showing an example of a wafer with shield processing according to Modification 3. [Figure 7] A side view showing an example of an electromagnetic wave shield sheet according to an embodiment. [Figure 8] A side view showing an example of an electromagnetic wave shield sheet according to a modification. [Figure 9] A schematic cross-sectional view showing an example of the main parts of a semiconductor device according to an embodiment. [Figure 10] A schematic cross-sectional view showing an example of the main part of a modified semiconductor device. [Figure 11] A schematic diagram illustrating an example of the manufacturing process for a semiconductor device according to an embodiment. [Figure 12] A schematic diagram illustrating an example of the manufacturing process for a semiconductor device according to an embodiment. [Figure 13] A schematic diagram illustrating an example of the manufacturing process for a semiconductor device according to an embodiment. [Figure 14] A schematic diagram illustrating an example of the manufacturing process for a semiconductor device according to an embodiment. [Figure 15] A schematic diagram illustrating an example of the manufacturing process for a semiconductor device according to an embodiment. [Modes for carrying out the invention]

[0009] The present disclosure will be described in detail below. Other embodiments are also included in the scope of this disclosure, insofar as they are consistent with the spirit of this disclosure. Numerical ranges specified using "~" in this specification include the values ​​indicated before and after the numerical value. Unless otherwise noted, each component in this specification may be used independently or in combination of two or more. Numerical values ​​described in this specification refer to values ​​obtained by methods described in the [Examples] and other sections below.

[0010] 1. Shielded wafers The shielded wafer of this disclosure is a wafer having a shield cover layer (hereinafter also referred to as the SC layer) formed by covering at least one main surface of a semiconductor wafer before pulverization with an electromagnetic shielding sheet (hereinafter also referred to as the ES sheet) of this disclosure. The ES sheet is a sheet for collectively covering a semiconductor wafer (hereinafter also simply referred to as the wafer) and has at least a shield film containing a binder component and a conductive filler (F). In this specification, conductive filler (F) (hereinafter also simply referred to as filler (F)) means a filler that reflects electromagnetic waves. The binder component is a matrix component that forms a layer, and examples include resins, curable compounds that can form a crosslinked structure by curing treatment, monomers, and oligomers.

[0011] This ES sheet has an elongation rate of 100-1500% at 100°C. Furthermore, the cured sheet obtained by treating this ES sheet at 180°C for 2 hours has a Young's modulus of 100-1000 MPa at 100°C. The cured sheet referred to here is the ES sheet cured independently without bonding to an adherend. The 2-hour treatment at 180°C is a curing condition used to specify the properties of this ES sheet. That is, the curing conditions for obtaining a shield cover layer by coating a wafer with this ES sheet are not limited to 2 hours at 180°C. The elongation rate is calculated as "100 × (length after elongation - original length) / (original length)".

[0012] The target material for coating with this ES sheet is a wafer before the fragmentation process. Specific examples include wafers with wafer-level chip-size packages (WL-CSP) formed on them before fragmentation, wafers with semiconductor elements formed on them before fragmentation, wafers with multilayer wiring structures formed on them before fragmentation, bare wafers, and wafers with a thermal oxide film obtained by high-temperature processing of a bare wafer.

[0013] The surface to be covered by this ES sheet may be either the element formation region surface or the back surface of the wafer, and either single-sided or double-sided covering is possible. With this ES sheet, the SC layer can be formed on the wafer in one go before individual piece formation, resulting in excellent productivity. Because this ES sheet has excellent conformability to uneven shapes, it is suitable for one-time covering of wafers having grid-shaped half-cut grooves and element formation regions partitioned by the half-cut grooves and arranged in a matrix. By covering the wafer in one go, including the half-cut grooves, the SC layer can be easily formed on the side surface of the semiconductor device after individual piece formation.

[0014] The area to be covered by this ES sheet may be the entire wafer or only a part of the wafer. For example, one configuration is to cover approximately 80% of the main surface area of ​​the wafer with the ES sheet all at once. A bare wafer is a wafer before processing, and examples include semiconductor substrates such as single-crystal silicon, gallium arsenide, and indium phosphide. The wafer diameter and thickness are arbitrary. Examples of bare wafer diameters are 100 mm, 150 mm, 200 mm, 300 mm, and 450 mm. Examples of bare wafer (semiconductor substrate) thickness are approximately 400 to 1000 μm.

[0015] Figure 1 shows a schematic diagram of an example of a shielded wafer according to this embodiment, and Figure 2 shows a cross-sectional view of the section II-II in Figure 1. As shown in Figure 2, the shielded wafer 101 has a multilayer wiring structure 14 formed on a semiconductor element formation wafer 1, and an SC layer 2 is covered on the semiconductor element formation wafer 1 and the multilayer wiring structure 14. By having an SC layer 2, electromagnetic waves generated from semiconductor elements on the semiconductor element formation wafer 1 or wiring in the multilayer wiring structure 14 can be shielded. In addition, electromagnetic waves from the outside can be shielded to prevent malfunction of semiconductor devices. The thickness of the SC layer can be appropriately designed depending on the application. The thickness of the SC layer is usually about 1 to 300 μm. The lower limit of the thickness is more preferably 3 μm, even more preferably 5 μm, and even more preferably 10 μm. The upper limit of the thickness is more preferably 150 μm, even more preferably 100 μm, and even more preferably 50 μm.

[0016] As shown in Figures 1 and 2, the shielded wafer 101 has a semiconductor element formation wafer 1, half-cut grooves 11 formed in a grid pattern in the X and Y axis directions of the semiconductor element formation wafer 1, and an element formation region 12 and SC layer 2 partitioned by the half-cut grooves 11 and arranged in a matrix. The element formation region 12 is a region that will be made into chips by a piecemaking process described later. As shown in Figure 1, the semiconductor element formation wafer 1 has notches 13 that serve as crystal orientation indicators at the edges of the semiconductor element formation wafer 1.

[0017] The half-cut groove 11 is a groove formed from the upper surface of the multilayer wiring structure 14 to partway along the thickness direction of the semiconductor substrate of the semiconductor element formation wafer 1, and is formed along scribe lines 17 formed in a grid pattern along the X and Y axes. The width of the half-cut groove 11 is, for example, 20 to 500 μm. The depth of the half-cut groove 11 from the upper surface of the semiconductor element formation wafer 1 is, for example, 40 to 600 μm. The half-cut groove 11 can be formed by known methods such as mechanical cutting with a rotary blade or laser grooving. The half-cut groove also includes an embodiment in which the groove is formed only in the multilayer wiring structure 14, where the groove does not reach the semiconductor element formation wafer 1.

[0018] The multilayer wiring structure 14, for example as shown in Figure 3, has a first insulating film 15a, a second insulating film 15b, and a third insulating film 15c laminated in that order, with multiple metal patterns such as wiring 16 formed in each layer. A surface protective film (not shown) or the like may be further formed on the upper layer of the multilayer wiring structure 14.

[0019] As described later, this SC layer consists of a single layer or multiple layers and has at least a shielding layer. The SC layer 2 shown in Figure 2 consists of a shielding layer 20. The shielding layer is a layer in which a shielding film containing a binder component and conductive filler (F) has been cured. The shielding layer 20 may be a single layer or multiple layers. The SC layer may also be a laminate of a shielding layer 20a and a non-shielding layer 21, as shown in Figure 4. The non-shielding layer 21 may be arranged on the multilayer wiring structure 14 side, as in the example in Figure 4, or vice versa. Examples of non-shielding layers 21 include a light-shielding layer, a hard coat layer, an insulating layer, a thermal conductive layer, and a protective layer. The non-shielding layer 21 may be a single layer or a multilayer of the same or different types.

[0020] The shielded wafer may be a wafer on which a wafer-level chip-size package (WL-CSP) is formed. Figure 5 shows a schematic cross-sectional view of an example of a shielded wafer of a WL-CSP before fragmentation. As shown in the figure, the shielded wafer 101b has electrode pads 4, a surface protective film 5, electrode posts 6, sealing resin 7, an SC layer 2, etc. on the upper surface of the semiconductor element-forming wafer 1. By fragmenting the shielded wafer 101b, a semiconductor device is obtained in which the sides are covered with an SC layer 2. The obtained semiconductor device is mounted on a printed circuit board (not shown) or the like via solder balls (not shown) placed on the electrode posts 6.

[0021] Figure 6 shows a schematic cross-sectional view of another example of a shielded wafer on which a WL-CSP is formed. The shielded wafer 101c has a multilayer wiring structure 14 on the upper surface of the semiconductor element formation wafer 1, and this multilayer wiring structure is sealed by a sealing resin 7. The semiconductor element formation wafer 1 and the sealing resin 7 are then covered with an SC layer 2. By separating the shielded wafer 101c into individual pieces, a semiconductor device covered with an SC layer 2 on its top and sides is obtained.

[0022] 2. Electromagnetic shielding sheet Figure 7 shows a schematic side view of an example of an ES sheet according to this embodiment. The ES sheet 3 shown in the figure consists of a shielding film 30. The shielding film 30 may be single-layered or multi-layered. The ES sheet may also be an ES sheet 3a, as shown in Figure 8, in which one or more shielding films 30 and one or more non-shielding films 31 are laminated. The shielding film 30 is covered to form a shielding layer 20. The non-shielding film 31 is covered to form a non-shielding layer 21. Examples of non-shielding films 31 include insulating films, thermally conductive films, light-shielding films, and hard-coat films. When the ES sheet has non-shielding films, it is preferable to ensure sufficient thickness of the shielding film from the viewpoint of fully exhibiting the shielding effect. From this viewpoint, it is preferable that 50 to 90% of the thickness of the ES sheet is shielding film, and more preferably 55 to 80%.

[0023] The elongation rate of this ES sheet at 100°C is set to 100-1500%. Furthermore, the Young's modulus of the cured sheet, obtained by treating this ES sheet at 180°C for 2 hours, is set to 100-1000 MPa at 100°C. By combining these, this ES sheet can improve the ability to conform to uneven shapes during pressing when the ES sheet is applied in one piece. It can also suppress wafer cracking and reduce wafer warping after curing. Moreover, it can suppress the peeling of the SC layer from the adherend and effectively suppress tearing in recesses such as half-cut grooves.

[0024] The lower limit of the elongation rate is more preferably 150%, and even more preferably 200%. The upper limit of the elongation rate is more preferably 1200%, and even more preferably 1000%. The lower limit of the Young's modulus is preferably 150 MPa, more preferably 200 MPa, and even more preferably 300 MPa. The upper limit of the Young's modulus is preferably 800 MPa, and even more preferably 600 MPa. If the ES sheet consists of a laminate of multiple films, each film does not need to satisfy the above conditions; it is sufficient that the ES sheet satisfies the above elongation rate and Young's modulus.

[0025] The thickness of this ES sheet can be designed as appropriate depending on the application. The thickness of this ES sheet is usually about 2 to 500 μm. The lower limit of the thickness is more preferably 5 μm, even more preferably 8 μm, and even more preferably 12 μm. The upper limit of the thickness is more preferably 300 μm, even more preferably 200 μm, and even more preferably 100 μm. This ES sheet is suitable for a coating layer that conforms to an uneven shape as shown in Figure 2, but it may also be applied to an embedded layer in which this ES sheet is embedded (filled) into recesses.

[0026] From the viewpoint of improving reliability, the ES sheet is preferably heat-pressed onto the entire main surface of a silicon bare wafer at 120°C and 5 MPa for 3 minutes, followed by processing at 180°C for 2 hours. In the electromagnetic shielding layer derived from the electromagnetic shielding sheet, the delamination rate in the adhesion test after performing a pressure cooker test according to JIS K5600-5-6 is preferably less than 15%, more preferably less than 10%, and even more preferably less than 5%.

[0027] When the ES sheet is heat-pressed onto the entire main surface of a 12-inch silicon bare wafer, on which half-cut grooves with a width of 200 μm and a depth of 200 μm are formed in a grid pattern at 4000 μm intervals, and then cured at 180°C for 3 minutes and cured at 180°C for 2 hours, the resistance value between the center of the SC layer covering the protrusions (in the example in Figure 6, the protrusions where the multilayer wiring structure portion 14 is sealed by the sealing resin 7) and the center of the same protrusions adjacent to it via the half-cut grooves (between the shield cover layers on adjacent protrusions) is preferably 5 to 300 mΩ. The upper limit of the resistance value is more preferably 150 mΩ, even more preferably 100 mΩ, and even more preferably 50 mΩ. The lower limit of the resistance value is more preferably 7 mΩ, even more preferably 10 mΩ, and even more preferably 15 mΩ.

[0028] As described above, the shielding film 30 contains a binder component and a conductive filler (F). The shielding film 30 becomes a cured shielding layer 20 by a heat curing treatment. The thickness of the shielding film 30 is, for example, 5 to 100 μm. From the viewpoint of achieving both wafer processability and electromagnetic wave shielding performance, the lower limit of the thickness of the shielding film 30 is preferably 7 μm, more preferably 10 μm, and even more preferably 20 μm. On the other hand, the upper limit of the thickness of the shielding film is preferably 90 μm, more preferably 75 μm, and even more preferably 50 μm.

[0029] 2-1. Shielding film The binder component of the shield film 30 plays a role in holding the filler (F) in the film and forming the film. The binder component includes components that form a cross-linked structure through a curing process.

[0030] A suitable example of a binder component is a combination of a high molecular weight resin (P) with a weight-average molecular weight (Mw) of 10,000 or more and a curable compound (C) with an Mw of 5,000 or less. By combining a high molecular weight resin (P) with an Mw of 10,000 or more and a curable compound (C) with an Mw of 5,000 or less, it is possible to achieve excellent film-forming properties of the ES sheet while also providing excellent conformability to uneven shapes and excellent coverage (embedding) of recesses such as half-cut grooves. The curable compound (C) may be an oligomer component or a low molecular weight compound. In the case of a low molecular weight compound, Mw should be read as molecular weight.

[0031] From the viewpoint of improving coverage of the half-cut grooves, the upper limit of Mw for the high molecular weight resin (P) is preferably 300,000, more preferably 250,000, even more preferably 200,000, and even more preferably 150,000. From the viewpoint of adjusting the elongation rate at 100°C, the lower limit of Mw for the high molecular weight resin (P) is more preferably 40,000, even more preferably 60,000, and even more preferably 80,000. There is a tendency for the elongation rate at 100°C to increase as Mw increases.

[0032] Examples of high molecular weight resins (P) include polyurethane resins, polyurethane urea resins, phenoxy resins, acrylic resins, polyester resins, polyamide resins, polystyrene resins, polycarbonate resins, polyamide-imide resins, polyesteramide resins, polyether ester resins, and polyimide resins. High molecular weight resins (P) can be used individually or in combination of two or more types.

[0033] The high molecular weight resin (P) may be a thermoplastic resin, a photocurable resin, or a thermosetting resin, but from the viewpoint of obtaining a highly reliable SC layer, it is preferable to include a thermosetting resin that can be crosslinked with a curable compound (C). The thermosetting resin is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, and may also be 100% by mass, based on 100% by mass of the high molecular weight resin (P).

[0034] The high molecular weight resin (P) preferably contains a thermosetting resin having reactive functional groups that react with the functional groups of the curable compound (C) to form a crosslinked structure. Examples of such reactive functional groups include carboxyl groups, hydroxyl groups, amino groups, epoxy groups, oxetanyl groups, oxazoline groups, oxazine groups, aziridine groups, thiol groups, isocyanate groups, blocked isocyanate groups, and silanol groups. Among these, carboxyl groups and hydroxyl groups are preferred in terms of storage stability of the electromagnetic shielding sheet.

[0035] The acid value of the high molecular weight resin (P) is preferably 3 to 30 mg KOH / g. By setting the acid value within this range, adhesion to the wafer is improved. The acid value is more preferably 4 to 25 mg KOH / g, and even more preferably 5 to 20 mg KOH / g. Examples of suitable thermosetting high molecular weight resins (P) include the aforementioned resins having carboxyl groups and / or hydroxyl groups (polyurethane resins, polyurethane urea resins, phenoxy resins, acrylic resins, polyester resins, polyamide resins, epoxy resins, polystyrene resins, polycarbonate resins, polyamide-imide resins, polyesteramide resins, polyether ester resins, and polyimide resins).

[0036] From the viewpoint of achieving both the above elongation rate at 100°C and the Young's modulus at 100°C after curing, the Tg of the high molecular weight resin (P) is preferably -20 to 40°C, more preferably -10 to 30°C, and even more preferably 0 to 20°C. If there are two or more types of high molecular weight resins (P), it is preferable that the main component high molecular weight resin (P) that is present in the largest amount satisfies the -20 to 40°C requirement, and the main component is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 90% by mass or more relative to the high molecular weight resin (P).

[0037] Curable compounds (C) with an Mw of 5,000 or less play a role in forming cross-linked structures, as well as enhancing flexibility when coating ES sheets and providing excellent conformability to uneven shapes. Furthermore, a highly reliable SC layer is obtained by constructing a cross-linked network after curing.

[0038] The content of the curable compound (C) is preferably 5 to 100 parts by mass per 100 parts by mass of the high molecular weight resin (P). The lower limit of the content of the curable compound (C) is more preferably 10 parts by mass, even more preferably 12 parts by mass, even more preferably 15 parts by mass, and particularly preferably 20 parts by mass. The upper limit of the content of the curable compound (C) is more preferably 80 parts by mass, even more preferably 70 parts by mass, even more preferably 60 parts by mass, and particularly preferably 50 parts by mass.

[0039] Examples of curable compounds (C) include epoxy group-containing compounds (E), isocyanate compounds, carbodiimide group-containing compounds, aziridine compounds, acid anhydride group-containing compounds, dicyandiamide compounds, aromatic diamine compounds and other amine compounds, organometallic compounds such as metal chelate compounds, maleimide group-containing compounds, and phenolic compounds such as phenol novolac resins. Among these, it is preferable to include epoxy group-containing compounds (E) from the viewpoint of increasing the flexibility of the ES sheet during coating and improving the reliability after coating. From the viewpoint of adjusting the curing rate of semi-curing (B-stage curing) and full curing (C-stage curing), it is preferable to use epoxy group-containing compounds (E) in combination with curable compounds other than epoxy group-containing compounds (E). A preferred example is a combination of epoxy group-containing compounds (E) and one or more selected from aziridine compounds, isocyanate compounds, and maleimide group-containing compounds.

[0040] In 100% by mass of the curable compound (C), the content of the epoxy group-containing compound (E) is preferably 50% by mass or more, more preferably 70% by mass, even more preferably 85% by mass, and even more preferably 90% by mass or more. The upper limit of the above content may be 100% by mass.

[0041] In 100% by mass of the curable compound (C), the other curable compound used in combination with the epoxy group-containing compound (E) is preferably 50% by mass or less, more preferably 30% by mass or less, even more preferably 15% by mass or less, and even more preferably 10% by mass or less. From the viewpoint of bringing out the effect of the other curable compound used in combination, the lower limit is preferably 0.1% by mass, more preferably 0.3% by mass, and even more preferably 0.4% by mass.

[0042] In 100 parts by mass of the binder component, the total content of high molecular weight resin (P) and epoxy group-containing compound (E) is preferably 70 parts by mass or more, more preferably 80 parts by mass or more, even more preferably 90 parts by mass or more, and may also be 100 parts by mass.

[0043] The epoxy group-containing compound (E) is not particularly limited as long as it has epoxy groups, but from the viewpoint of adjusting the Young's modulus at 100°C to 100-1000 MPa of the cured sheet after treating the electromagnetic wave shielding sheet at 180°C for 2 hours, a bifunctional or polyfunctional epoxy group-containing compound (E) is preferred. In hot pressing or the like, the epoxy groups of the epoxy group-containing compound (E) thermally crosslink with the carboxyl groups or hydroxyl groups of the thermosetting resin to obtain a crosslinked structure. From the viewpoint of improving the flexibility and conformability in the coating process of the ES sheet and effectively eliciting stress relaxation after coating, an epoxy group-containing compound (E) that is liquid at room temperature and atmospheric pressure is preferred as the epoxy group-containing compound (E).

[0044] From the viewpoint of easily obtaining an SC layer having the above Young's modulus, the epoxy group equivalent of the epoxy group-containing compound (E) is preferably 110 to 1000 g / eq. The lower limit of the epoxy group equivalent is more preferably 115 g / eq, and even more preferably 150 g / eq. The upper limit of the epoxy group equivalent is more preferably 900 g / eq, even more preferably 750 g / eq, even more preferably 500 g / eq, and particularly preferably 280 g / eq. From the viewpoint of more effectively increasing flexibility, the epoxy group-containing compound (E) is preferably contained in 10 to 80 parts by mass per 100 parts by mass of the high molecular weight resin (P). By using the above blending amounts, the flexibility of the shield film can be increased. By setting the epoxy equivalent of the epoxy group-containing compound (E) to 110 to 1000 g / eq, the crosslinking density in the semi-cured product of the shield film can be adjusted to effectively increase edge coverage. Here, "edge" refers to the edges, corners, etc., of the uneven parts. The epoxy equivalent is expressed as the number of grams [g / eq] of epoxy compound containing 1 gram equivalent of epoxy groups, and is determined according to the method specified in JIS K 7236.

[0045] Examples of epoxy group-containing compounds (E) include glycidyl ether type epoxy compounds, glycidylamine type epoxy compounds, glycidyl ester type epoxy compounds, and cyclic aliphatic (alicyclic) epoxy compounds. Examples of glycidyl ether type epoxy compounds include bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, bisphenol S type epoxy compounds, bisphenol AD ​​type epoxy compounds, cresol novolac type epoxy compounds, phenol novolac type epoxy compounds, α-naphthol novolac type epoxy compounds, bisphenol A type novolac type epoxy compounds, dicyclopentadiene type epoxy compounds, tetrabrom bisphenol A type epoxy compounds, brominated phenol novolac type epoxy compounds, tris(glycidyloxyphenyl)methane, and tetrakis(glycidyloxyphenyl)ethane. Examples of glycidylamine-type epoxy compounds include tetraglycidyldiaminodiphenylmethane, triglycidylparaaminophenol, triglycidylmethaminophenol, and tetraglycidylmetaxylylenediamine. Examples of glycidyl ester-type epoxy compounds include diglycidyl phthalate, diglycidyl hexahydrophthalate, and diglycidyl tetrahydrophthalate. Examples of cyclic aliphatic (alicyclic) epoxy compounds include epoxycyclohexylmethyl-epoxycyclohexanecarboxylate and bis(epoxycyclohexyl)adipate. Liquid epoxy compounds can also be suitably used.

[0046] The epoxy group-containing compound (E) preferably also has other functional groups besides the epoxy group. Examples of other functional groups include hydroxyl groups, secondary amino groups, and tertiary amino groups. By using an epoxy group-containing compound (E) having such other functional groups in addition to two or more functional epoxy groups, the crosslinking density under predetermined curing conditions can be effectively increased, thereby improving PCT resistance. Furthermore, the presence of hydroxyl groups and / or amino groups enhances adhesion to the substrate, such as a wafer, and as a result, good PCT resistance and adhesion can be simultaneously satisfied.

[0047] The binder component may contain components other than those mentioned above, as long as it does not deviate from the spirit of this disclosure. For example, it may contain resins such as tackifying resins, thermoplastic resins, thermosetting resins, and photocurable resins with an Mw of less than 10,000. Examples of tackifying resins include rosin-based resins, terpene-based resins, alicyclic petroleum resins, and aromatic petroleum resins.

[0048] Examples of conductive fillers (F) include metal particles, conductive metal oxide particles, particles containing conductive polymers, and metal-coated particles. Examples of metal particles include metal powders such as gold, silver, copper, palladium, aluminum, nickel, iron, titanium, manganese, zinc, tungsten, platinum, lead, and tin, as well as alloy powders such as solder, steel, and stainless steel, and core-shell type fillers such as silver-coated copper powder, gold-coated copper powder, silver-coated nickel powder, and gold-coated nickel powder. Excellent conductivity can be obtained by using a silver-containing filler (F). The silver content in silver-coated copper is preferably 6 to 20% by mass, more preferably 8 to 17% by mass, and even more preferably 10 to 15% by mass, based on 100% by mass of filler (F). In the case of core-shell type fillers, the coverage rate of the coating layer on the core portion is preferably 60% by mass or more on average, more preferably 70% by mass or more, and even more preferably 80% by mass or more, based on 100% by mass of the entire surface. Examples of metal oxide particles include conductive zinc oxide, indium oxide, and tin oxide. Examples of particles having a conductive polymer include polyacetylene particles, polythiophene particles, polypyrrole particles, or particles coated with these materials on their surface. Examples of metal-coated particles include resin particles whose surface is coated with a metal such as gold or silver, and inorganic particles such as glass or ceramic whose surface is coated with a metal. Examples of conductive carbon materials include carbon black, acetylene black, Ketjenblack, graphite, carbon nanotubes, graphene, fullerene, carbon nanocoils, carbon microcoils, and carbon fibers.

[0049] Examples of the shape of the filler (F) include flaky (scaly), dendritic, fibrous, acicular, or spherical fillers. The filler (F) is used alone or in combination. When used in combination, examples include a combination of flaky filler and dendritic filler, a combination of flaky filler, dendritic filler, and spherical filler, and a combination of flaky filler and spherical filler. Among these, from the viewpoint of enhancing the edge coverage of the SC layer, a flaky filler alone or a combination of a flaky filler and a dendritic filler is more preferable.

[0050] The average particle diameter D of the flaky filler 50 is preferably 0.5 to 50 μm, more preferably 1 to 30 μm. Even more preferably, it is 2 to 20 μm, and particularly preferably 2 to 10 μm. The average particle diameter D of the dendritic filler (F) 50 The preferred range is similarly preferably 2 to 100 μm, more preferably 2 to 80 μm. Even more preferably, it is 3 to 50 μm, and particularly preferably 5 to 20 μm.

[0051] The specific surface area of the flaky filler is preferably 0.2 to 4.0 m 2 / g, more preferably 0.4 to 3.5 m 2 / g. Even more preferably, it is 0.5 to 3.0 m 2 / g, and particularly preferably 1.0 to 2.5 m 2 / g. The average particle diameter D of the dendritic filler 50 The preferred range is similarly preferably 0.2 to 2.0 m 2 / g, more preferably 0.3 to 1.8 μm. Even more preferably, it is 0.4 to 1.6 m 2 / g, and particularly preferably 0.5 to 1.5 m 2 / g.

[0052] From the viewpoint of obtaining excellent electromagnetic wave shielding properties, the content of the filler (F) is preferably 45 to 85% by mass based on 100% by mass of the sheet. The lower limit value is more preferably 50% by mass, and even more preferably 55% by mass. The upper limit value is more preferably 82% by mass, and even more preferably 80% by mass.

[0053] Average specific surface area of ​​filler (F) [m²] 2 The product of [g] 2 Preferably, 100-1000m 2 This is more preferable. Even more preferable is 200-800m 2 And, particularly preferably, 300-600m 2 That is the case.

[0054] The shielding film may contain an electromagnetic wave absorbing filler in addition to the conductive filler (F). Examples of electromagnetic wave absorbing fillers include dielectric loss electromagnetic wave absorbing materials such as carbon particles, or magnetic loss electromagnetic wave absorbing materials such as ferrite or soft magnetic metal powder.

[0055] Examples of electromagnetic wave absorbing fillers include iron, iron alloys such as Fe-Ni alloy, Fe-Co alloy, Fe-Cr alloy, Fe-Si alloy, Fe-Al alloy, Fe-Cr-Si alloy, Fe-Cr-Al alloy, and Fe-Si-Al alloy, ferrite materials such as Mg-Zn ferrite, Mn-Zn ferrite, Mn-Mg ferrite, Cu-Zn ferrite, Mg-Mn-Sr ferrite, and Ni-Zn ferrite, and carbon fillers. Examples of carbon fillers include acetylene black, Ketjen black, furnace black, carbon black, carbon fiber, fillers made of carbon nano-nanotubes, graphene fillers, graphite fillers, and carbon nanowalls.

[0056] This ES sheet is particularly suitable for applications where a wafer with half-cut grooves is to be covered all at once. Furthermore, this ES sheet can be applied to a general range of applications where electromagnetic shielding is desired by attaching it to a substrate. It can also provide shielding effects to the sides of semiconductor devices. Additionally, because it allows for single-piece covering, it offers greater design flexibility and versatility.

[0057] The elongation rate of this ES sheet at 100°C can be adjusted by the type, molecular weight, content, and functional groups of the binder components of this sheet. For example, it can be adjusted by adjusting the blending amounts of high molecular weight resin (P) and epoxy group-containing compound (E). Increasing the Mw of the high molecular weight resin (P) tends to increase the elongation rate. Also, decreasing the Tg of the high molecular weight resin (P) tends to increase the elongation rate. The elongation rate of this ES sheet at 100°C can be adjusted by keeping the epoxy group equivalent of the epoxy group-containing compound (E) within the aforementioned range. Furthermore, the elongation rate can be adjusted by the combination of high molecular weight resin (P) and epoxy group-containing compound (E).

[0058] The Young's modulus at 100°C of the cured ES sheet after treatment at 180°C for 2 hours tends to increase with increasing filler content. Furthermore, the Young's modulus tends to increase with higher Tg or higher acid value of the high molecular weight resin (P).

[0059] Alternatively, or in combination with the above method, a method can be used to control the Young's modulus at 100°C to 1000 MPa in a cured sheet after treating the ES sheet at 180°C for 2 hours by controlling the type and amount of filler (F). Average particle size D of filler (F) 50 Changing the BET specific surface area, tap density, and surface treatment is also effective in controlling Young's modulus.

[0060] In a method to achieve a peel rate of less than 15% in an adhesion test after a pressure cooker test based on JIS K5600-5-6 on the SC layer derived from the ES sheet, which was heat-pressed onto the entire main surface of a silicon bare wafer at 120°C and 5 MPa for 3 minutes and then treated at 180°C for 2 hours, the type and amount of high molecular weight resin (P) and epoxy group-containing compound (E) can be adjusted. As the Mw of the high molecular weight resin (P) increases, the internal cohesive force of the sheet can be increased, and the peel rate tends to decrease. Also, as the acid value of the high molecular weight resin (P) increases, the interaction at the interface with the substrate such as the wafer can be increased, and the peel rate tends to decrease. Furthermore, the adhesion strength can be adjusted by adjusting the acid value and Mw of the high molecular weight resin (P) and the epoxy equivalent of the epoxy group-containing compound (E).

[0061] The shield film may contain organic fillers other than filler (F), inorganic fillers, and various additives, to the extent that it does not depart from the spirit of this disclosure. Specifically, it may contain monomers, oligomers, curing accelerators, curing retarders, silane coupling agents, colorants, flame retardants, antistatic agents, antioxidants, softeners, surface modifiers, lubricants, antiblocking agents, adhesion improvers, etc.

[0062] 2-2. Non-shielded film Non-shielded films contain at least a binder component. Non-shielded films may also contain organic fillers and / or inorganic fillers. By compositing organic or inorganic fillers with the binder component, the properties of the binder component can be improved. For example, mechanical properties, thermal properties, processability, flame retardancy, transparency, refractive index, heat dissipation, dispersibility, etc., can be imparted.

[0063] Examples of inorganic fillers include inorganic compounds such as silica, alumina, titanium dioxide, zinc oxide, antimony trioxide, magnesium oxide, tin oxide, zirconium oxide, magnesium hydroxide, barium sulfate, calcium carbonate, talc, kaolinite, mica, sericite, montmorrolinite, bentonite, magnesium carbonate base, boron nitride, aluminum nitride, and titanium nitride.

[0064] Suitable examples of binder components include resins similar to those used in shielding films. Fillers can be appropriately selected depending on the function of the non-shielding film. For example, if you want to impart thermal conductivity to a non-shielded film, examples of materials that can be used include conductive fillers, nitrides such as boron nitride, aluminum nitride, and gallium nitride; metal oxides such as aluminum oxide, silicon oxide (silicon dioxide), titanium oxide, zirconium oxide, zinc oxide, tin oxide, copper oxide, and nickel oxide; metal hydroxides and hydrated metal compounds such as aluminum hydroxide, boehmite, magnesium hydroxide, calcium hydroxide, zinc hydroxide, silica, iron hydroxide, copper hydroxide, barium hydroxide, zirconium oxide hydrate, tin oxide hydrate, basic magnesium carbonate, hydrotalcite, dosonite, borax, and zinc borate; carbides such as silicon carbide, boron carbide, nitrogen carbide, and calcium carbide; carbonates such as calcium carbonate; titanates such as barium titanate and potassium titanate; carbon-based materials such as carbon black, carbon tubes (carbon nanotubes), carbon fiber, and diamond; and glass.

[0065] 2-3. Method for manufacturing electromagnetic shielding sheets The manufacturing method of this ES sheet will be described below. However, the manufacturing method of this ES sheet is not limited to the method described below.

[0066] First, a resin composition for obtaining the film constituting this ES sheet is prepared. The resin composition for obtaining the shield film is obtained by mixing a filler (F), a binder component, and a solvent, etc. The mixing method is not limited, as long as the components are mixed uniformly. The resin composition for obtaining a non-shielding film, such as a protective film, is obtained by mixing a binder component and a solvent, etc.

[0067] To improve the uniform dispersion of the filler, a mixing device may be used. Examples include agitators equipped with blades (Henschel mixer, pressure kneader, Banbury mixer, planetary mixer, etc.), grinding devices equipped with media (ball mill, attritor, basket mill, sand mill, sand grinder, Dino mill, disper mat, SC mill, spike mill or agitator mill, etc.), and dispersion devices equipped with other mechanisms (microfluidizer, nanomizer, ultimateizer, ultrasonic homogenizer, desolver, disperser, high-speed impeller, rotational agitator, colloid mill, thin-film swirling high-speed mixer, etc.). Mixing may also be performed while degassing.

[0068] The viscosity of the resin composition can be appropriately set according to the desired film thickness. A shielded film is obtained by coating the prepared resin composition onto a release substrate and heating and drying it. A non-shielded film is similarly obtained by coating the prepared resin composition onto a release substrate and heating and drying it. Examples of coating methods for the resin composition include gravure coating, kiss coating, die coating, lip coating, comma coating, blade coating, roll coating, knife coating, spray coating, bar coating, spin coating, and dip coating.

[0069] If the ES sheet consists only of a shield film, the ES sheet can be obtained by peeling the film from a release substrate. If the ES sheet has a laminated structure of a shield film and a non-shield film, the films can be laminated together to join them. Alternatively, a laminate can be obtained by coating a resin composition for forming a non-shield film onto a shield film formed on a release substrate and then heat-drying it. Alternatively, a laminate can be obtained by coating a resin composition for forming a shield film onto a non-shield film formed on a release substrate and then heat-drying it. The non-shield film is, for example, a protective film.

[0070] 3. Semiconductor device and method for manufacturing the same Figure 9 shows a schematic cross-sectional view of an example of a main part of a semiconductor device obtained by framing a shielded wafer. In the semiconductor device 201, the shielded wafer is framing into element formation region units, and the SC layer 2 obtained by heating and curing an ES sheet covers from the element formation region 12 to the half-cut groove 11. The SC layer 2 may be heat-cured before or after framing.

[0071] Figure 10 shows a schematic cross-sectional view of an example of a modified semiconductor device. In the example in Figure 9, an example was described in which the SC layer 2 is covered along the side walls and bottom of the half-cut groove, but as shown in Figure 10, the SC layer 2 may be filled throughout the entire half-cut groove. When the width of the half-cut groove is narrow, it is effective to fill the half-cut groove with the SC layer 2 and then dicing the wafer and the SC layer 2 along the scribe line.

[0072] An example of a method for manufacturing the semiconductor device described below. However, the method for manufacturing the semiconductor device described herein is not limited to the following method.

[0073] First, to form a circuit pattern on the bare wafer, the bare wafer is subjected to high-temperature treatment to form an oxide film on the surface of the bare wafer. Next, a photosensitive photoresist, insulating layer, wiring pattern, etc., are formed to form a semiconductor device-forming wafer 1, and then a multilayer wiring structure 14, etc., is formed (see Figure 11). Next, a surface protective film is formed as needed. Then, along the scribe line 17 (see Figure 1), a half-cut groove 11 is formed from the surface of the semiconductor device-forming wafer 1 to partway down the wafer (see Figure 12). The half-cut groove can be formed by mechanical cutting with a rotating blade or by laser grooving.

[0074] As a specific example, a wafer is fixed in a vacuum-suctioned state in the vacuum chuck of a dicing apparatus. Then, dicing is performed from the surface side of the wafer along the scribe lines in the X direction and the scribe lines in the Y direction using a dicing blade, thereby forming half-cut grooves 11 that reach into the wafer.

[0075] Next, the ES sheet 3 is placed on the semiconductor element forming wafer 1 in which the half-cut groove 11 is formed. To improve the coverage of the half-cut groove 11 by the ES sheet 3, it is preferable to place a cushion sheet 33 on the ES sheet 3, as shown in Figure 13. In addition, if necessary, a reinforcing sheet 34 may be laminated on top of the cushion sheet 33.

[0076] By providing the cushion sheet 33, the conformability of the ES sheet 3 to the half-cut groove 11 can be improved. The cushioning material is a layer that melts during hot pressing and is made of a material that has release properties. The reinforcing sheet transmits the pressing force to the cushion sheet, improving the embedding of the ES sheet into the stepped portion of the adherend.

[0077] The semiconductor element formation wafer 1 is fixed to the vacuum suction stage 50 (see Figure 14), and the laminate of ES sheet 3 / cushion sheet 33 / reinforcement sheet 34 is heat-pressed. Before heat-pressing, the ES sheet 3 may be temporarily attached to the upper surface of the semiconductor element formation wafer 1. This temporary attachment method can be achieved, for example, by lightly heat-pressing the ES sheet 3 onto the entire surface or edges of the semiconductor element formation wafer 1 with a heat source.

[0078] The reinforcing sheet 34 can be appropriately selected from resin films, metal plates, etc. Examples include plastic sheets such as polyethylene terephthalate, polyethylene naphthalate, polyvinyl fluoride, polyvinylidene fluoride, rigid polyvinyl chloride, polyvinylidene chloride, nylon, polyimide, polystyrene, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polycarbonate, polyacrylonitrile, polybutene, flexible polyvinyl chloride, polyvinylidene fluoride, polyethylene, polypropylene, polyurethane resin, ethylene vinyl acetate copolymer, and polyvinyl acetate; papers such as glassine paper, fine paper, kraft paper, and coated paper; various nonwoven fabrics, synthetic paper, metal foil, and composite films combining these. Among these, polyethylene terephthalate, polyester, polycarbonate, polyimide, and polyphenylene sulfide are preferred from the viewpoint of handling and cost. Polyethylene terephthalate and polyimide are even more preferred.

[0079] The cushion layer 33' obtained from the cushion sheet 33 preferably has a release layer formed on the bonding surface with the ES sheet to facilitate peeling from the SC layer after hot pressing. Examples of such release layers include polypropylene, polymethylpentene, cyclic olefin polymer, silicone, and fluororesin.

[0080] Commercially available cushioning layers include "CR1012," "CR1012MT4," "CR1031," "CR1033," "CR1040," and "CR2031MT4" manufactured by Mitsui Tohcello Co., Ltd. These commercially available cushioning layers often have a layer structure in which the cushioning layer is sandwiched between polymethylpentene as a release layer on both sides. In this specification, the integrated structure including the release layer is referred to as a cushion sheet. By laminating a reinforcing sheet onto one side of this, embedding properties and substrate cracking can be improved.

[0081] The thickness of the cushion sheet is preferably 50 to 300 μm, more preferably 75 to 250 μm, and even more preferably 100 to 200 μm. A thickness of 50 μm or more improves embedding properties. A thickness of 300 μm or less improves the handling properties of the ES sheet. Note that the above cushion layer thickness includes the release layer if one is present.

[0082] The thickness of the reinforcing sheet 34 is preferably 20 μm or more, more preferably 25 μm or more, and even more preferably 38 μm or more. By increasing the thickness of the reinforcing sheet to 20 μm or more, the strength of the reinforcing sheet is improved, which further improves its embeddability, release properties, and handling properties. There are no particular restrictions on the thickness of the reinforcing sheet, but a thickness of 250 μm or less is preferred because it improves the release properties and handling properties of the ES sheet.

[0083] The SC layer 2 is formed on the semiconductor element formation wafer 1 by thermally pressing the ES sheet 3 onto the wafer. A press substrate 40 is lowered from above the reinforcing sheet 34 and thermally pressed (see Figure 15). The ES sheet 3 is stretched along the half-cut grooves provided on the wafer by the pressure from the melting of the cushion sheet 33, and covers the multilayer wiring structure 14 and the half-cut grooves 11, forming the SC layer 2 (see Figure 15).

[0084] The temperature in the hot pressing process is preferably above the melting temperature of the cushion sheet 33 and below the melting temperature of the reinforcing sheet 34. This temperature allows the cushion sheet to melt while maintaining the strength of the reinforcing sheet. The heating temperature in the hot pressing process is preferably 100°C or higher, more preferably 110°C or higher, and even more preferably 120°C or higher. The upper limit depends on the heat resistance of the multilayer wiring structure 14, but is preferably 220°C or lower, more preferably 200°C or lower, and even more preferably 180°C or lower.

[0085] The pressure in the hot pressing process is set appropriately according to the wafer thickness to prevent the wafer from cracking. For example, it is about 1 to 15 MPa. More preferably, it is 1.5 to 10 MPa, and even more preferably, 2 to 5 MPa. The hot pressing time is, for example, about 1 minute to 2 hours. The curing process may be completed during the hot pressing process, or a separate curing process may be provided after the hot pressing. The thermosetting resin in the binder component may be partially or substantially cured before the hot pressing process, provided that it is still flowable. The hot pressing apparatus can be a press-type hot pressing apparatus, a transfer molding apparatus, a compression molding apparatus, a vacuum pressure forming apparatus, etc.

[0086] Subsequently, the pressed substrate 40 is released, and the cushion layer 33' and reinforcing sheet 34 are removed. Through these steps, a shielded wafer as shown in Figure 2 is obtained. The top surface may be removed by etching, as shown in Figure 5.

[0087] In the above embodiment, an example was described in which the ES sheet 3, cushion sheet 33, and reinforcing sheet 34 are used in overlapping layers. However, laminates joined in any combination may also be used. For example, laminates of ES sheet / cushion sheet / reinforcing sheet, ES sheet / cushion sheet, and cushion sheet / reinforcing sheet may be used. By joining the reinforcing sheet and the cushion sheet, the peelability can be greatly improved.

[0088] Next, a framing process is performed along the scribe line. Specifically, the shielded wafer is framing. The framing method can be the same as for the half-cut groove, such as mechanical cutting with a rotary blade or laser grooving. Alternatively, the wafer can be cut by polishing the back side to reduce the wafer thickness up to the half-cut groove. [Examples]

[0089] The present disclosure will be further illustrated below with reference to examples, but this will not limit the scope of the disclosure in any way. In the examples, "parts" and "%" refer to "parts by mass" and "mass%", respectively.

[0090] (a)Measurement method The numerical values ​​obtained in this embodiment were obtained by the following method. (i) Weight average molecular weight (Mw) Mw was measured using the HPC-8020 GPC (gel permeation chromatography) system manufactured by Tosoh Corporation. GPC is a liquid chromatography system that separates and quantifies substances dissolved in a solvent (THF; tetrahydrofuran) based on differences in their molecular size. The measurement was performed using two LF-604 columns (Showa Denko Corporation: rapid analysis GPC column: 6mm ID × 150mm size) connected in series, with a flow rate of 0.6 mL / min and a column temperature of 40°C. The weight-average molecular weight (Mw) was determined in polystyrene equivalent.

[0091] (ii) Acid value of resin Precisely weigh out approximately 1 g of resin into a stoppered Erlenmeyer flask and dissolve it in 50 mL of a toluene / ethanol mixture (volume ratio: toluene / ethanol = 2 / 1). Add phenolphthalein reagent as an indicator and hold for 30 seconds. Then, titrate with 0.1 mol / L alcoholic potassium hydroxide solution until the solution turns pale pink. The acid value was determined by the following formula. The acid value was taken from the dry state of the resin. Acid value (mgKOH / g)=(a×F×56.1×0.1) / S S: Sample volume × (Solid content of sample / 100) (g) a: Titration volume (mL) of 0.1 mol / L alcoholic potassium hydroxide solution F: Titer of 0.1 mol / L alcoholic potassium hydroxide solution

[0092] (iii) Tg of resin Tg was measured using a dynamic viscoelasticity analyzer DVA-200 (manufactured by IT Measurement Control Co., Ltd.) in accordance with JIS K7198. A 50 μm thick PET film coated with a silicone release agent was prepared as the release substrate. The resin was applied to this release substrate using a doctor blade to a thickness of 20 μm, dried at 100°C for 2 minutes, and the resulting sheet was cut into 0.5 cm × 3 cm pieces. The release film was peeled off and used for measurement. The measurement was performed using tensile deformation mode, with a strain of 0.08%, a frequency of 10 Hz, and a heating rate of 10°C / min. Tg was defined as the temperature at which the main dispersion peak of the loss loss tangent (tanδ) appeared.

[0093] (iv) Preparation of test half-cut wafers A bare silicon wafer (size 100 mmφ, thickness 525 μm) was prepared, and a test half-cut wafer was obtained by forming half-cut grooves with a width of 200 μm and a depth of 200 μm at a 4000 μm grid angle using a dicing device (DISCO DAD323).

[0094] (b) Manufacturing of resin compositions, electromagnetic shielding sheets and laminates [Preparation of the resin composition of Example 1] A resin composition was obtained by placing 100 parts of the solids content of high molecular weight resin P3, 40 parts of epoxy group-containing compound E3, 1 part of curable compound C1, 180 parts of filler F2, and 35 parts of filler F4 into a container, adding a mixed solvent of toluene:isopropyl alcohol (mass ratio 2:1) to achieve a non-volatile content (solids) concentration of 35%, and stirring with a disperser for 10 minutes. The solids content amounts of each component are listed in Table 1.

[0095] [Examples 2-20 and Comparative Examples 1-6] The resin composition was prepared in the same manner as in Example 1, except for the modifications shown in Tables 1-3.

[0096] The materials used in the examples and the abbreviations in Tables 1-3 are shown below. <Binder ingredients> [High molecular weight resin (P)] P1: Polycarbonate resin, Mw=180,000, acid value 10 [mgKOH / g], Tg 10℃ (manufactured by Toyo Chem Co., Ltd.) P2: Polycarbonate resin, Mw=260,000, acid value 10 [mgKOH / g], Tg 10℃ (manufactured by Toyo Chem Co., Ltd.) P3: Polycarbonate resin, Mw=120,000, acid value 10 [mgKOH / g], Tg 10℃ (manufactured by Toyo Chem Co., Ltd.) P4: Polycarbonate resin, Mw=110,000, acid value 12 [mgKOH / g], Tg -10℃ (manufactured by Toyo Chem Co., Ltd.) P5: Polycarbonate resin, Mw=50,000, acid value 18 [mgKOH / g], Tg 20℃ (manufactured by Toyo Chem Co., Ltd.) P6: Polycarbonate resin, Mw=110,000, acid value 3 [mgKOH / g], Tg 10℃ (manufactured by Toyo Chem Co., Ltd.) P7: Polycarbonate resin, Mw=110,000, acid value 28 [mgKOH / g], Tg 10℃ (manufactured by Toyo Chem Co., Ltd.) P8: Urethane resin, Mw=130,000, acid value 10 [mgKOH / g], Tg 40℃ (manufactured by Toyo Chem Co., Ltd.) P9: Urethane resin, Mw=130,000, acid value 10 [mgKOH / g], Tg 60℃ (manufactured by Toyo Chem Co., Ltd.) P10: Ester resin, Mw=140,000, acid value 10 [mgKOH / g], Tg -15℃ (manufactured by Toyo Chem Co., Ltd.) [Other resins] R1: Acrylic resin, Mw=8,000, acid value 15 [mgKOH / g] (manufactured by Toyo Chem Co., Ltd.) <Curable compound (C)> • C1: "Chemitite PZ-33" (aziridine compound, Mw=425), manufactured by Nippon Shokubai Co., Ltd. [Epoxy group-containing compound (E)] • E1: "jER604" (diaminodiphenylmethane type epoxy resin, Mw=350, epoxy equivalent=120g / eq) manufactured by Mitsubishi Chemical Corporation. • E2: "jER1032H" (trisphenolmethane type epoxy resin, Mw=500, epoxy equivalent=170g / eq) Manufactured by Mitsubishi Chemical Corporation. • E3: "jER834" (Bisphenol A type epoxy resin, Mw=470, epoxy equivalent=250g / eq) Manufactured by Mitsubishi Chemical Corporation • E4: "EPICLON1050" (Bisphenol A type epoxy resin, Mw=900, epoxy equivalent=475g / eq) manufactured by DIC Corporation. • E5: "EPICLON3050" (Bisphenol A type epoxy resin, Mw=1800, epoxy equivalent=800g / eq) manufactured by DIC Corporation. [Other curing compounds] • R2: "jER1010" (Bisphenol A type epoxy resin, Mw=5500, epoxy equivalent=4000g / eq) Manufactured by Mitsubishi Chemical Corporation <Conductive filler (F)> ·F1: Scale-like silver filler (D 50 =1.0~3.0μm, average specific surface area 1.1m 2 / g) Manufactured by Tokusen Kogyo Co., Ltd. • F2: Scale-like silver filler (D 50 =4.0~7.0μm, average specific surface area 1.5m 2 / g) Manufactured by Fukuda Metal Industry Co., Ltd. F3: Scale-like silver filler (D 50 =5.0~10.0μm, average specific surface area 0.3m 2 / g) Manufactured by Fukuda Metal Industry Co., Ltd. ·F4: Dendritic silver-coated copper filler (D 50 =7.4μm, average specific surface area 0.7m 2 / g) Manufactured by Mitsui Mining & Smelting Co., Ltd. F5: Dendritic silver-coated copper filler (scale silver filler D) 50 =10.4μm, average specific surface area 0.6m 2 / g) Made by DOWA Corporation

[0097] [Table 1]

[0098] [Table 2]

[0099] [Table 3]

[0100] (Manufacturing of electromagnetic shielding sheets) A 50 μm thick PET film coated with a silicone release agent on its surface was prepared as a release substrate. The resin compositions of each example and comparative example were applied to this release substrate using a doctor blade to a dry thickness of 40 μm. Then, by drying at 100°C for 2 minutes, electromagnetic wave shielding sheets with release substrates according to each example and comparative example were obtained.

[0101] (Fabrication of laminates) Subsequently, a release cushioning material was prepared, and the sheet surface of the electromagnetic wave shielding sheet with the release substrate of each example and comparative example and the cushioning sheet (CR1040 manufactured by Mitsui Tohcello Co., Ltd.) were laminated using a thermal laminator at a temperature of 70°C, a pressure of 0.1 MPa, and a speed of 1 m / min to obtain the laminate according to each example and comparative example.

[0102] (c) Characteristics of electromagnetic shielding sheets, etc. The elongation rate and Young's modulus for the above examples and comparative examples were determined by the following method. The results are shown in Tables 1 to 3. <Elongation rate at 100℃> For each example, the electromagnetic shielding sheets, from which the release substrate and cushioning sheet had been peeled off, were left to stand for 24 hours in a constant temperature and humidity chamber at 23°C and 50% relative humidity. After that, they were left to stand for 1 minute in a chamber maintained at 100°C. Subsequently, at a temperature of 100°C, the electromagnetic shielding sheets were subjected to a tensile test using an "EZ Tester" (manufactured by Shimadzu Corporation) under conditions of a tensile speed of 50 mm / min and a gauge length of 25 mm. The stress-strain curve was measured, and the elongation at the fracture point was measured and defined as the elongation at 100°C.

[0103] <Young's modulus of cured sheet at 100°C> The electromagnetic wave shielding sheet from which the release substrate and the cushion sheet were peeled off was heated at 180°C for 2 hours to obtain a cured sheet. After standing still at 23°C and 50% relative humidity in a thermo-hygrostat chamber, it was left standing for 1 minute in a chamber maintained at 100°C. Then, under a temperature of 100°C, the stress-strain curve of the cured sheet was measured with a tensile tester "EZ Tester" (manufactured by Shimadzu Corporation) under the conditions of a tensile speed of 50 mm / min and a gauge length of 25 mm. The linear regression (slope) in the region where the strain (elongation) was 0.1 to 0.3% was measured and taken as the Young's modulus at 100°C.

[0104] (d) Evaluation of electromagnetic wave shielding sheets, etc. For the above-mentioned examples and comparative examples, the adhesion, coating property, warp, and appearance were evaluated by the following methods. The results are shown in Table 4. <Adhesion of silicon to the bare wafer after PCT test> A silicon bare wafer (size: 100 mmφ, thickness: 525 μm) was prepared. The above-mentioned laminate was cut into 50 mm × 50 mm, the release substrate was peeled off, and the electromagnetic wave shielding sheet layer was placed on the bare wafer. Then, heat pressing was performed on the bare wafer from above the cushion sheet of the laminate under the conditions of a temperature of 120°C and a pressure of 5 MPa for 3 minutes. After heat pressing, it was cooled and the cushion layer was peeled off, and a test piece in which a shield cover layer was formed by heating at 180°C for 2 hours was obtained. Next, a pressure cooker test (conditions: 130°C, 85% RH, 0.12 MPa, 96 hours) was performed on this test substrate. Then, 100 squares with an interval of 1 mm were formed on the shield cover layer of the test substrate using a cross-cut guide in accordance with JIS K5400. Then, an adhesive tape was strongly pressure-bonded to the square portion, the end of the tape was quickly peeled off at an angle of 45°, and the state of the square was evaluated according to the following criteria. +++: Peeling rate is less than 5%. ++: The coating film is partially peeled along the cut line, and the peeling rate is 5% or more and less than 10%. +: The coating film is partially peeled along the cut line, and the peeling rate is 10% or more and less than 15%. NG: The paint film is partially or completely peeling along the cut line, and the peeling rate is 15% or more. Unusable.

[0105] <Resistance between half-cut grooves> The laminate was cut to a diameter of 100 mm, the release agent was peeled off, and the electromagnetic shielding sheet layer was placed on a test half-cut wafer. Then, the test half-cut wafer was hot-pressed from above the cushion sheet of the laminate at a temperature of 120°C and a pressure of 5 MPa for 3 minutes. After hot-pressing, it was cooled, and then the cushion layer was peeled off, and the shielded wafer was obtained by heating at 180°C for 2 hours. Then, using a HIOKI RM3544 and a pin-type lead probe, the probe was applied to the center of the upper surface of the shield cover layer of two adjacent semiconductor element formation regions, and the resistance value between the half-cut grooves was evaluated. The evaluation criteria are as follows. +++: Resistance is less than 50mΩ. This is a very good result. ++: Resistance value is between 50mΩ and 150mΩ. This is a good result. +: Resistance value is between 150mΩ and 300mΩ. No practical problems. NG: Resistance value is 300mΩ or higher. Not practical for use.

[0106] <Height of curvature> The shielded wafer obtained above was placed on a horizontal surface, and the maximum distance between the surface and the wafer edge was measured to evaluate the warp height. The evaluation criteria are as follows: +++: Warp height is less than 1 mm. This is a very good result. ++: Warp height is between 1mm and 2mm. This is a good result. +: Warp height is between 2mm and 5mm. No practical problems. NG: Curvature height of 5mm or more. Not practical for use.

[0107] <Appearance of individual pieces> From the top surface of the shielded wafer obtained above, a dicing device (DISCO DAD323) was used to perform a full cut with a width of 50 μm, passing through the center of the half-cut groove, to obtain 100 individual pieces. The appearance was then visually inspected, and the number of individual pieces with peeling or chipping of the electromagnetic shielding sheet was counted. The evaluation criteria are as follows. +++: Fewer than 5 individual pieces have peeling or chipping of the electromagnetic shielding sheet. Very good. ++: The number of individual pieces with peeling or chipping of the electromagnetic shielding sheet is between 5 and 10. Good. +: The number of individual pieces with peeling or chipping of the electromagnetic shielding sheet is between 10 and 20. This does not pose a practical problem. NG: More than 20 individual pieces have peeling or chipping of the electromagnetic shielding sheet. Unusable.

[0108] [Table 4]

[0109] Electromagnetic shielding sheets with a Young's modulus at 100°C exceeding 1000 MPa in the cured sheet exhibited high resistance between half-cut grooves, as shown in Comparative Examples 2 and 4, resulting in problems with coverage of recessed areas. When the Young's modulus at 100°C of the cured sheet was less than 100 MPa, peelability after PCT testing deteriorated, as shown in Comparative Examples 1 and 3, resulting in problems with adhesion to the substrate. Even if the Young's modulus at 100°C of the cured sheet was less than 1000 MPa, high elongation at 100°C resulted in good peelability after PCT testing, but high resistance between half-cut grooves was observed, as shown in Comparative Example 5, resulting in problems with coverage of recessed areas. In contrast, by using an electromagnetic shielding sheet with an elongation at 100°C of 100-1500% and a Young's modulus at 100°C of 100-1000 MPa after treatment at 180°C for 2 hours, superior adhesion, coverage, warping, and appearance were confirmed, as shown in Examples 1 to 28. [Explanation of Symbols]

[0110] 1. Semiconductor device formation wafer 2. Shield cover layer 3. Electromagnetic shielding sheet 11 Half-cut grooves 12 Element formation region 13 Notches 14 Multilayer wiring high-rise section 15a First insulating film 15b Second insulating film 15c Third insulating film 16 Wiring 17 Scribeline 20 Shield Layers 21 Unshielded layer 30 Shield Film 31 Non-shielding film 33 Cushion Seat 34 Reinforcement Sheet 40 Pressed circuit boards 50 Vacuum adsorption stage 101 Shielded wafer 201 Semiconductor Equipment

Claims

1. An electromagnetic wave shielding sheet for covering at least one of the main surfaces of a semiconductor wafer before fractionation, which has half-cut grooves formed in a grid pattern and element formation regions partitioned by the half-cut grooves and arranged in a matrix pattern, The electromagnetic wave shielding sheet comprises at least a shielding film containing a binder component and a conductive filler (F), The electromagnetic shielding sheet has an elongation rate of 100 to 1500% at 100°C. An electromagnetic wave shielding sheet wherein the cured sheet obtained by treating the electromagnetic wave shielding sheet at 180°C for 2 hours has a Young's modulus of 100 to 1000 MPa at 100°C.

2. The electromagnetic wave shielding sheet according to claim 1, wherein the electromagnetic wave shielding sheet is heat-pressed onto the entire main surface of a silicon bare wafer at 120°C and 5 MPa for 3 minutes, and then treated at 180°C for 2 hours, and the peel rate in the adhesion test after performing a pressure cooker test according to JIS K5600-5-6 on the shield cover layer derived from the electromagnetic wave shielding sheet is less than 15%.

3. The electromagnetic wave shielding sheet according to claim 1, wherein the binder component comprises a curable compound (C) having a weight-average molecular weight of 5,000 or less and a high molecular weight resin (P) having a weight-average molecular weight of 10,000 or more.

4. The electromagnetic wave shielding sheet according to claim 1, wherein the conductive filler (F) content is 45 to 85% by mass.

5. Average specific surface area [m²] of conductive filler (F) ２ The product of [g] ２ The electromagnetic wave shielding sheet according to claim 1.

6. The curable compound (C) contains an epoxy group-containing compound (E) with a weight-average molecular weight of 5,000 or less. The epoxy equivalent of epoxy group-containing compound (E) is 110 to 1000 g / eq. The electromagnetic wave shielding sheet according to claim 1, comprising 10 to 80 parts by mass of an epoxy group-containing compound (E) per 100 parts by mass of a high molecular weight resin (P).

7. The electromagnetic shielding sheet according to claim 1, wherein the electromagnetic shielding sheet is heat-pressed onto the entire main surface of a 12-inch silicon bare wafer, on which half-cut grooves with a width of 200 μm and a depth of 200 μm are formed in a grid pattern at 4000 μm intervals, and a shield cover layer derived from the electromagnetic shielding sheet is formed after being heat-pressed onto the wafer at 120°C and 5 MPa for 3 minutes and then treated at 180°C for 2 hours, and the resistance between the shield cover layers covering adjacent protrusions via the half-cut grooves is 5 to 300 mΩ.

8. A shielded wafer having a shield cover layer formed on at least one main surface of a semiconductor wafer before pulverization, which is made of an electromagnetic wave shielding sheet according to any one of claims 1 to 7.

9. A semiconductor device in which the shielded wafer according to claim 8 is fragmented into individual element formation regions.

10. A semiconductor wafer before piece formation having an element formation region formed in a matrix along a scribe line, comprising the steps of forming a half-cut groove, A step of placing an electromagnetic wave shielding sheet according to any one of claims 1 to 7 above the semiconductor wafer, A step of thermally pressing the electromagnetic wave shielding sheet onto the semiconductor wafer, The process of obtaining a shield cover layer by heating and curing the electromagnetic wave shielding sheet, A method for manufacturing a semiconductor device, comprising the step of fragmenting the device into individual element formation regions.

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