Back grinding tape and method for manufacturing electronic device

Abstract

Provided is a back grinding tape (100) capable of protecting a circuit formation surface of an electronic component in a step of grinding the electronic component, wherein the back grinding tape (100) is provided with a resin layer (A) (10), the Vicat softening point of the resin constituting the resin layer (A) (10) is 45°C or higher, and the embedding depth measured by a predetermined method is 10 μm or more.

Description

Backgrind tape and method for manufacturing electronic device

[0001] The present invention relates to a backgrinding tape and a method for manufacturing an electronic device.

[0002] Some manufacturing methods for electronic devices include a process of backgrinding (grinding) the surface of the electronic component opposite to the circuit-formed surface after forming the circuit on the electronic component (e.g., semiconductor wafer, etc.). In these processes, backgrinding tape is used to protect the circuit-formed surface of the electronic component.

[0003] As a technique relating to backgrinding tape, for example, the technique described in Patent Document 1 can be mentioned.

[0004] Patent Document 1 describes an adhesive tape for protecting the surface of a semiconductor wafer, which comprises a base film and a pressure-sensitive adhesive layer provided on the base film, and which is used in a step of polishing the backside of a semiconductor wafer by laminating a semiconductor wafer having an uneven surface to the pressure-sensitive adhesive layer, the adhesive strength to SUS being 1.3 to 10.0 N / 25 mm when measured in accordance with JIS Z 0237 at a peel angle of 90° and a peel rate of 50 mm / min, and which is characterized in that the base film is flattened by grinding the unevenness formed by transferring the unevenness when the semiconductor wafer is laminated to the base film before polishing the backside of the semiconductor wafer. According to the adhesive tape for protecting the surface of a semiconductor wafer described in Patent Document 1, even if the back surface of the adhesive tape for protecting the surface of a semiconductor wafer, i.e., the base film, is ground, the adhesive tape for protecting the surface of a semiconductor wafer does not peel off from the semiconductor wafer, and the unevenness formed on the back surface of the adhesive tape for protecting the surface of a semiconductor wafer, which is formed when the semiconductor wafer is laminated and is transferred from the unevenness of the surface of the semiconductor wafer, can be flattened by grinding the base film, eliminating the need to separately mold a resin and then grind the resin, thereby preventing the process from becoming complicated. Furthermore, according to the adhesive tape for protecting the surface of a semiconductor wafer described in Patent Document 1, the back surface of the adhesive tape for protecting the surface of a semiconductor wafer can be flattened well, and as a result, the thickness accuracy when the back surface of the semiconductor wafer is polished is improved.

[0005] JP 2014-192464 A

[0006] In recent years, with the miniaturization of electronic devices, there has been a demand for thinner electronic components after grinding and for improved thickness precision (TTV) of electronic components after grinding.

[0007] The present invention has been made in view of the above circumstances, and provides a backgrinding tape and a method for manufacturing an electronic device that can improve the thickness accuracy of electronic components.

[0008] According to the present invention, there are provided the following backgrind tape and electronic device manufacturing methods.

[0009] [1] A backgrinding tape capable of protecting the circuit-forming surface of an electronic component during a grinding process, the backgrinding tape comprising a resin layer (A), the resin constituting the resin layer (A) having a Vicat softening point of 45°C or higher, and an embedding depth measured by the following method 1 of 10 μm or more. [Method 1] A silicon wafer having a groove M of 50 μm width and 70 μm depth is heated to 90°C, and with the groove M in contact with one surface (SB surface) of the backgrinding tape, a φ7 mm compression disk terminal is attached to a digital force gauge from the surface (SA surface) of the backgrinding tape opposite the SB surface, and a load of 30 N is applied continuously for 30 seconds. After the load is applied, the silicon wafer to which the backgrinding tape is attached is cooled to 23°C, and the backgrinding tape is then peeled off from the silicon wafer. The amount of deformation in the height direction of the portion of the SB surface of the backgrind tape where the shape of the groove M is transferred is defined as the embedding amount. [2] The backgrind tape according to [1] above, wherein the proportion of the resin layer (A) in the backgrind tape is 65 volume % or more. [3] The backgrind tape according to [1] or [2] above, wherein the backgrind tape is composed of a single layer of the resin layer (A). [4] The density of the resin constituting the resin layer (A) is 880 kg / m ３The backgrinding tape according to any one of [1] to [3], wherein the resin constituting the resin layer (A) comprises at least one selected from the group consisting of ethylene-α-olefin copolymer, ethylene-vinyl ester copolymer, low-density polyethylene, polyvinyl chloride, and propylene-α-olefin copolymer. [6] The backgrinding tape according to any one of [1] to [5], wherein the backgrinding tape does not comprise an adhesive layer, or wherein the backgrinding tape further comprises an adhesive layer, and the adhesive layer has a thickness of less than 10 μm. [7] The backgrinding tape according to any one of [1] to [6], wherein the thickness of the backgrinding tape is 50 μm or more and 1000 μm or less. [8] The backgrinding tape according to any one of [1] to [7], wherein the backgrinding tape can be used in a manufacturing method for an electronic device, which includes a step of planarizing the surface of the backgrinding tape prior to the step of grinding the electronic component. [9] A method for manufacturing an electronic device, comprising: a step (A) of preparing a structure comprising an electronic component having a circuit formation surface and a backgrind tape, the structure being formed by bonding the circuit formation surface of the electronic component to one surface (SB surface) of the backgrind tape; a step (B) of flattening a surface (SA surface) of the backgrind tape opposite the SB surface of the backgrind tape in the structure; and a step (C) after step (B) of grinding the surface of the electronic component opposite the circuit formation surface, wherein the backgrind tape comprises a resin layer (A), the Vicat softening point of the resin constituting the resin layer (A) is 45°C or higher, and the embedding depth measured by Method 2 below is 10 μm or higher. [Method 2] A silicon wafer having a groove M of 50 μm width and 70 μm depth is heated to 90° C., and with the groove M in contact with the SB surface of the backgrind tape, a φ7 mm compression disk terminal is attached to a digital force gauge and a load of 30 N is applied from the SA surface for 30 seconds. After the load is applied, the silicon wafer with the backgrind tape attached is cooled to 23° C., and the backgrind tape is then peeled off from the silicon wafer.The amount of deformation in the height direction of the portion of the SB surface of the backgrind tape where the shape of the groove M is transferred is defined as the embedding amount.

[10] The method for manufacturing an electronic device according to [9] above, further comprising step (D) of removing the backgrind tape from the structure after step (C).

[11] The method for manufacturing an electronic device according to [9] or

[10] above, wherein the proportion of the resin layer (A) in the backgrind tape is 65 volume % or more.

[12] The method for manufacturing an electronic device according to any one of [9] to

[11] above, wherein the backgrind tape consists of a single layer of the resin layer (A).

[13] The density of the resin constituting the resin layer (A) is 880 kg / m. ３

[14] The method for manufacturing an electronic device according to any one of [9] to

[13] above, wherein the resin constituting the resin layer (A) comprises at least one selected from the group consisting of ethylene-α-olefin copolymer, ethylene-vinyl ester copolymer, low-density polyethylene, polyvinyl chloride, and propylene-α-olefin copolymer.

[15] The method for manufacturing an electronic device according to any one of [9] to

[14] above, wherein the backgrinding tape does not include a pressure-sensitive adhesive layer, or wherein the backgrinding tape further comprises a pressure-sensitive adhesive layer, and the pressure-sensitive adhesive layer has a thickness of less than 10 μm.

[16] The method for manufacturing an electronic device according to any one of [9] to

[15] above, wherein the thickness of the backgrinding tape is 50 μm or more and 1000 μm or less.

[0010] According to the present invention, it is possible to provide a backgrinding tape and a method for manufacturing an electronic device that can improve the thickness accuracy of electronic components.

[0011] It is a cross-sectional view showing an example of the back grinding tape of the present embodiment. It is a view for explaining Method 1. It is a cross-sectional view showing an example of the structure in Step (A).

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all drawings, similar components are designated by common reference numerals, and descriptions thereof will be omitted where appropriate. The drawings are schematic and do not correspond to actual dimensional ratios. Numerical ranges "A to B" represent A or more and B or less unless otherwise specified. In this specification, "(meth)acrylic" means "at least one of acrylic and methacrylic."

[0013] A conventional method for manufacturing an electronic device includes, for example, preparing a structure in which an electronic component and a backgrinding tape are bonded together, and grinding the surface of the electronic component in the structure opposite the surface to which the backgrinding tape is bonded. The inventors' investigations revealed that unevenness on the surface of the backgrinding tape opposite the electronic component in the structure before grinding can cause deterioration in the thickness accuracy of the electronic component after grinding. In particular, when the electronic component has an uneven structure, the thickness unevenness of the backgrinding tape tends to worsen.

[0014] The inventors have investigated a method for manufacturing an electronic device that improves the thickness accuracy of electronic components after grinding, which includes a step of grinding and flattening the surface of the backgrinding tape in a structure in which the electronic component and the backgrinding tape are bonded together before the step of grinding the electronic component.

[0015] However, the inventors' investigations have revealed that such a method for manufacturing an electronic device leaves room for improvement in terms of improving the thickness accuracy of the electronic components. Furthermore, the inventors have discovered that, with such a method for manufacturing an electronic device, there is a trade-off between the grinding properties of the backgrinding tape (hereinafter also referred to as "tape grinding properties") and the thickness accuracy of the electronic components.

[0016] The present invention has been made in consideration of the above circumstances, and provides a backgrinding tape and a method for manufacturing an electronic device that can improve the thickness accuracy of electronic components.Furthermore, the present invention can provide a backgrinding tape and a method for manufacturing an electronic device that can improve the performance balance between tape grinding ability and thickness accuracy of electronic components.

[0017] [Backgrinding Tape] The backgrinding tape of this embodiment is a backgrinding tape capable of protecting the circuit formation surface of an electronic component during the process of grinding the electronic component, and the backgrinding tape has a resin layer (A), the resin constituting the resin layer (A) has a Vicat softening point of 45°C or higher, and the embedding amount measured by Method 1 is 10 µm or higher.

[0018] As described above, there is a demand for a backgrinding tape that can improve the thickness accuracy of electronic components. As a result of intensive research, the present inventors have found that, in a backgrinding tape having a resin layer (A), the Vicat softening point of the resin constituting the resin layer (A) and the embedding amount measured by Method 1 are effective design indicators for improving the thickness accuracy of electronic components.

[0019] 1 is a cross-sectional view showing an example of the backgrind tape of the present embodiment. The backgrind tape 100 includes a resin layer (A) 10.

[0020] The embedment amount of the backgrinding tape 100 measured by Method 1 is 10 μm or more. From the viewpoint of further improving the thickness precision of electronic components, the embedment amount of the backgrinding tape 100 is preferably 15 μm or more, more preferably 20 μm or more, even more preferably 30 μm or more, even more preferably 40 μm or more, even more preferably 50 μm or more, even more preferably 55 μm or more, even more preferably 60 μm or more, even more preferably 62 μm or more, and even more preferably 64 μm or more, and the upper limit is not particularly limited, but may be, for example, 70 μm or less.

[0021] [Method 1] A silicon wafer with a 50 μm wide, 70 μm deep groove M is heated to 90°C, and with the groove M in contact with one side (SB side) of the backgrind tape, a φ7 mm compression disk terminal is attached to a digital force gauge from the side (SA side) opposite the SB side of the backgrind tape, and a load of 30 N is applied for 30 seconds. After the load is applied, the silicon wafer with the backgrind tape attached is cooled to 23°C, and then the backgrind tape is peeled off from the silicon wafer. The amount of deformation in the height direction at the point on the SB side of the backgrind tape where the groove M shape is transferred is taken as the embedding amount.

[0022] FIG. 2 is a diagram illustrating Method 1. Method 1 will be described in detail using FIG. 2. First, a silicon wafer 200 having a groove M with a width of 50 μm and a depth of 70 μm is prepared. Next, the silicon wafer 200 is heated to 90°C. With the groove M of the silicon wafer 200 in contact with the SB surface of the backgrinding tape 100 (FIG. 2(a)), a φ7 mm compression disk terminal 300 is attached to a digital force gauge (not shown) from the SA surface of the backgrinding tape, and a load of 30 N is applied for 30 seconds (FIG. 2(b)). After the silicon wafer 200 is cooled to 23°C, the backgrinding tape 100 is peeled off from the silicon wafer 200. The amount of deformation H in the height direction at the location on the SB surface of the backgrinding tape 100 where the shape of the groove M is transferred is defined as the embedding amount (FIG. 2(c)).

[0023] The embedding amount of the backgrind tape 100 can be adjusted to the desired value by appropriately adjusting, for example, the type of resin constituting the resin layer (A) 10; the thickness of the resin layer (A) 10; the proportion of the resin layer (A) 10 in the backgrind tape 100; etc.

[0024] The thickness of the backgrind tape 100 is preferably 50 μm or more, more preferably 70 μm or more, even more preferably 100 μm or more, even more preferably 120 μm or more, even more preferably 140 μm or more, even more preferably 150 μm or more, and preferably 1000 μm or less, more preferably 800 μm or less, even more preferably 600 μm or less, even more preferably 400 μm or less, even more preferably 300 μm or less, even more preferably 200 μm or less. The thickness of the backgrind tape 100 is preferably 50 μm or more and 1000 μm or less, more preferably 70 μm or more and 800 μm or less, even more preferably 100 μm or more and 600 μm or less, even more preferably 120 μm or more and 400 μm or less, even more preferably 140 μm or more and 300 μm or less, even more preferably 150 μm or more and 200 μm or less.

[0025] Each layer of the backgrind tape 100 will now be described.

[0026] <Resin Layer (A)> The backgrinding tape 100 includes a resin layer (A) 10 .

[0027] The resin constituting the resin layer (A) 10 has a Vicat softening point of 45° C. or higher. From the viewpoint of further improving tape grindability and further improving the thickness accuracy of electronic components, the Vicat softening point of the resin constituting the resin layer (A) 10 is preferably 47° C. or higher, more preferably 50° C. or higher, even more preferably 53° C. or higher, even more preferably 55° C. or higher, and even more preferably 57° C. or higher. The upper limit is not particularly limited, but may be, for example, 190° C. or lower, 180° C. or lower, 150° C. or lower, 120° C. or lower, 100° C. or lower, or 70° C. or lower. The Vicat softening point of the resin constituting the resin layer (A) 10 is preferably 45 ° C. or higher and 190 ° C. or lower, more preferably 47 ° C. or higher and 180 ° C. or lower, even more preferably 50 ° C. or higher and 150 ° C. or lower, even more preferably 53 ° C. or higher and 120 ° C. or lower, even more preferably 55 ° C. or higher and 100 ° C. or lower, and even more preferably 57 ° C. or higher and 70 ° C. or lower, from the viewpoint of further improving tape grindability and further improving the thickness accuracy of electronic components. The Vicat softening point of the resin constituting the resin layer (A) 10 means a value measured in accordance with ASTM D 1525. Here, when two or more resins are used to constitute the resin layer (A) 10, the Vicat softening point of the resin constituting the resin layer (A) 10 can be the Vicat softening point of a mixture obtained by melt blending two or more resins by a known method.

[0028] The type of resin constituting the resin layer (A) 10 is not particularly limited, but preferably contains at least one selected from the group consisting of ethylene-α-olefin copolymer, ethylene-vinyl ester copolymer, low-density polyethylene, polyvinyl chloride, and propylene-α-olefin copolymer, more preferably contains at least one selected from the group consisting of ethylene-α-olefin copolymer and ethylene-vinyl ester copolymer, and even more preferably contains at least one selected from the group consisting of ethylene-α-olefin copolymer and ethylene-vinyl acetate copolymer.

[0029] In the ethylene / α-olefin copolymer, the α-olefin is, for example, an α-olefin having from 3 to 20 carbon atoms, preferably an α-olefin having from 3 to 10 carbon atoms, more preferably an α-olefin having from 3 to 8 carbon atoms, and even more preferably an α-olefin having from 3 to 5 carbon atoms. Examples of such α-olefins include propylene, 1-butene, 1-pentene, 1-hexene, 3-methyl-1-butene, 3,3-dimethyl-1-butene, 4-methyl-1-pentene, 1-octene, 1-decene, and 1-dodecene, and among these, propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, and 1-octene are preferred. The ethylene / α-olefin copolymer may be a random copolymer or a block copolymer.

[0030] In the propylene-α-olefin copolymer, the α-olefin is, for example, an α-olefin having from 2 to 20 carbon atoms (excluding propylene), preferably an α-olefin having from 2 to 10 carbon atoms (excluding propylene), more preferably an α-olefin having from 2 to 8 carbon atoms (excluding propylene), and even more preferably an α-olefin having from 2 to 5 carbon atoms (excluding propylene). Examples of such α-olefins include ethylene, 1-butene, 1-pentene, 1-hexene, 3-methyl-1-butene, 3,3-dimethyl-1-butene, 4-methyl-1-pentene, 1-octene, 1-decene, and 1-dodecene, and among these, ethylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, and 1-octene are preferred. The propylene-α-olefin copolymer may be a random copolymer or a block copolymer.

[0031] Examples of ethylene-vinyl ester copolymers include ethylene-vinyl acetate copolymers, ethylene-vinyl propionate copolymers, ethylene-vinyl butyrate copolymers, and ethylene-vinyl stearate copolymers, and among these, ethylene-vinyl acetate copolymers are preferred.

[0032] The density of the resin constituting the resin layer (A) 10 is preferably 880 kg / m from the viewpoint of further improving tape grindability and further improving the thickness precision of the electronic component. ３ More preferably, 885 kg / m ３ More preferably, 890 kg / m ３ The upper limit is not particularly limited, but is, for example, 1500 kg / m ３ or less, 1200 kg / m ３ or less, 1000 kg / m ３ The density of the resin constituting the resin layer (A) 10 is preferably 880 kg / m or less from the viewpoint of further improving tape grindability and further improving the thickness accuracy of the electronic component. ３ More than 1500kg / m ３ or less, more preferably 885 kg / m ３ More than 1200kg / m ３ More preferably, 890 kg / m or less ３ More than 1000kg / m ３ The density of the resin constituting the resin layer (A) 10 means a value measured in accordance with ASTM D 1505. Here, when two or more types of resins are used to constitute the resin layer (A) 10, the density of the resin constituting the resin layer (A) 10 can be the density of a mixture obtained by melt-blending two or more types of resins by a known method.

[0033] The thickness of the resin layer (A) 10 is preferably 50 μm or more, more preferably 70 μm or more, even more preferably 100 μm or more, even more preferably 120 μm or more, even more preferably 140 μm or more, even more preferably 150 μm or more, and preferably 1000 μm or less, more preferably 800 μm or less, even more preferably 600 μm or less, even more preferably 400 μm or less, even more preferably 300 μm or less, even more preferably 200 μm or less. The thickness of the resin layer (A) 10 is preferably 50 μm or more and 1000 μm or less, more preferably 70 μm or more and 800 μm or less, even more preferably 100 μm or more and 600 μm or less, even more preferably 120 μm or more and 400 μm or less, even more preferably 140 μm or more and 300 μm or less, even more preferably 150 μm or more and 200 μm or less.

[0034] The proportion of the resin layer (A) 10 in the backgrind tape 100 is preferably 65% ​​by volume or more, more preferably 75% by volume or more, even more preferably 80% by volume or more, more preferably 90% by volume or more, even more preferably 95% by volume or more, even more preferably 97% by volume or more, even more preferably 99% by volume or more, and for example, 100% by mass or less. Here, the proportion of the resin layer (A) 10 is a value when the backgrind tape in a state where it is attached to an electronic component is taken as 100% by volume. In other words, the backgrind tape 100 may be provided with a protective film or the like that is peeled off when attached to an electronic component, but such a protective film is not included in the reference value of the volume of the backgrind tape.

[0035] The resin layer (A) 10 may contain components such as a filler in addition to the resin component. The content of the components other than the resin component is an appropriate amount.

[0036] The content of the resin component in the resin layer (A) 10 is preferably 60% 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, even more preferably 95% by mass or more, even more preferably 97% by mass or more, even more preferably 99% by mass or more, and is, for example, 100% by mass or less, when the total content of all components contained in the resin layer (A) 10 is 100% by mass.

[0037] <Other Layers> The backgrinding tape 100 may include other layers in addition to the resin layer (A) 10 as appropriate.

[0038] The other layers include, for example, a layer made of a protective film. The protective film is provided to protect the backgrinding tape 100 and is peeled off when the backgrinding tape is attached to an electronic component.

[0039] The backgrind tape 100 preferably comprises a single layer of resin layer (A) 10. Here, the above description means that when the backgrind tape is attached to an electronic component, the backgrind tape 100 comprises a single layer of resin layer (A) 10. For example, if the backgrind tape 100 has a two-layer structure comprising a single layer of resin layer (A) 10 and a protective film, the protective film is peeled off when the backgrind tape is attached to the electronic component, and therefore the backgrind tape 100 comprises a single layer of resin layer (A) 10 when attached to the electronic component.

[0040] The backgrinding tape 100 preferably does not include an adhesive layer, or the backgrinding tape further includes an adhesive layer, and the thickness of the adhesive layer is less than 10 μm, more preferably does not include an adhesive layer. If the backgrinding tape 100 further includes an adhesive layer, the thickness of the adhesive layer is more preferably less than 5 μm, even more preferably less than 3 μm, and even more preferably less than 1 μm. The adhesive layer is, for example, a layer made of a known adhesive. Examples of adhesives include (meth)acrylic adhesives and silicone adhesives.

[0041] <Method for manufacturing backgrind tape> The method for manufacturing the backgrind tape 100 is not particularly limited, but examples include a method for manufacturing the backgrind tape by forming a resin layer (A) by extrusion molding a resin; a method for manufacturing the backgrind tape by applying a resin to a resin film and drying it to form a resin layer (A); and the like.

[0042] <Uses of Backgrind Tape> The backgrind tape 100 is a backgrind tape that can protect the circuit-forming surface of an electronic component during the process of grinding the electronic component, and is preferably a backgrind tape that can be used in a method for manufacturing an electronic device that includes a step of planarizing the surface of the backgrind tape prior to the step of grinding the electronic component. The backgrind tape 100 is more preferably used in the method for manufacturing an electronic device described below. A preferred aspect of the step of grinding the electronic component is the same as the preferred aspect of step (C) in the method for manufacturing an electronic device described below, and a preferred aspect of the step of planarizing the surface of the backgrind tape is the same as the preferred aspect of step (B) in the method for manufacturing an electronic device described below.

[0043] [Method for Manufacturing Electronic Device] The method for manufacturing an electronic device of this embodiment includes the steps of: preparing a structure including an electronic component having a circuit formation surface and a backgrind tape, the structure including the circuit formation surface of the electronic component and one surface (SB surface) of the backgrind tape bonded together; planarizing a surface (SA surface) of the backgrind tape opposite the SB surface in the structure; and, after step (B), grinding the surface of the electronic component opposite the circuit formation surface, the backgrind tape including a resin layer (A), the resin constituting the resin layer (A) having a Vicat softening point of 45°C or higher, and an embedding depth measured by Method 2 of 10 μm or higher.

[0044] [Method 2] A silicon wafer with a 50 μm wide, 70 μm deep groove M is heated to 90°C, and with the groove M in contact with the SB surface of the backgrind tape, a φ7 mm compression disk terminal is attached to a digital force gauge from the SA surface, and a load of 30 N is applied for 30 seconds. After the load is applied, the silicon wafer with the backgrind tape attached is cooled to 23°C, and then the backgrind tape is peeled off from the silicon wafer. The amount of deformation in the height direction at the point on the SB surface of the backgrind tape where the shape of the groove M is transferred is taken as the embedding amount.

[0045] The preferred embodiment of the backgrind tape used in the method for manufacturing an electronic device according to this embodiment is the same as the preferred embodiment of the backgrind tape described above. Note that the preferred embodiment of the embedding amount measured by Method 2 is the same as the preferred embodiment of the embedding amount measured by Method 1.

[0046] The electronic device in this embodiment is meant to include, for example, semiconductor devices, power semiconductor devices, semiconductor chips, semiconductor elements, printed wiring boards, electric circuit display devices, information and communication terminals, light-emitting diodes, physical batteries, chemical batteries, and other elements, devices, and final products to which electronic engineering technology is applied.

[0047] Each step in the manufacturing of the electronic device of this embodiment will be described below.

[0048] 3 is a cross-sectional view schematically illustrating an example of a structure 500 in step (A). The method for manufacturing an electronic device according to the present embodiment includes step (A) of preparing a structure 500 including an electronic component 400 having a circuit formation surface 400A and backgrinding tape 100, in which the circuit formation surface 400A side of electronic component 400 and one surface (SB surface) of backgrinding tape 100 are bonded together.

[0049] The structure 500 can be produced by bonding the backgrind tape 100 to the circuit formation surface 400A of the electronic component 400. The method for bonding the backgrind tape 100 to the circuit formation surface 400A of the electronic component 400 is not particularly limited, and bonding can be performed by a known method. For example, the bonding may be performed manually or by a device called an automatic bonding machine to which a roll of backgrind tape 100 is attached.

[0050] When the backgrind tape 100 is bonded to the circuit formation surface 400A of the electronic component 400, for example, the bonding may be performed while heating at least one of the electronic component 400 and the backgrind tape 100. The heating temperature is not particularly limited, but may be, for example, 40°C or higher, 60°C or higher, 150°C or lower, or 120°C or lower.

[0051] The electronic component 400 is not particularly limited, and examples thereof include a semiconductor wafer, a sapphire substrate, a lithium tantalate substrate, a mold wafer, a mold panel, a mold array package, a semiconductor substrate, etc., among which a semiconductor wafer is preferable. Examples of the semiconductor wafer include a silicon wafer, a sapphire wafer, a germanium wafer, a germanium-arsenic wafer, a gallium-phosphorus wafer, a gallium-arsenic-aluminum wafer, a gallium-arsenic wafer, a lithium tantalate wafer, etc., among which a silicon wafer is preferable.

[0052] The circuit-forming surface 400A of the electronic component 400 has, for example, circuits such as wiring, capacitors, diodes, or transistors formed on its surface. The circuit-forming surface 400A may also be plasma-treated. The circuit-forming surface 400A of the electronic component 400 preferably has an uneven structure. Generally, when the circuit-forming surface 400A of the electronic component 400 has an uneven structure, the uneven structure tends to reduce the thickness accuracy of the structure 500, and the thickness accuracy of the electronic component 400 after grinding tends to be reduced. On the other hand, the method for manufacturing an electronic device according to the present embodiment is capable of improving the thickness accuracy of the electronic component, and therefore, even when the circuit-forming surface 400A of the electronic component 400 has an uneven structure, the thickness accuracy of the electronic component is improved.

[0053] The above-mentioned uneven structure preferably includes a bump electrode. For example, when mounting an electronic device on a mounting surface, the bump electrode is bonded to an electrode formed on the mounting surface to form an electrical connection between the electronic device and the mounting surface (such as the mounting surface of a printed circuit board). Examples of the bump electrode include ball bumps, printed bumps, stud bumps, plated bumps, and pillar bumps. That is, the bump electrode is usually a convex electrode. These bump electrodes may be used alone or in combination of two or more types.

[0054] The height of the bump electrode is preferably 2 μm or more, more preferably 5 μm or more, even more preferably 10 μm or more, even more preferably 50 μm or more, and preferably 600 μm or less, more preferably 500 μm or less, even more preferably 400 μm or less, and even more preferably 300 μm or less. The preferred range of the diameter of the bump electrode is the same as the preferred range of the height of the bump electrode. The bump pitch of the bump electrode is not particularly limited, but is preferably 5 μm or more, more preferably 50 μm or more, even more preferably 100 μm or more, and preferably 600 μm or less, more preferably 500 μm or less. Here, the bump pitch of the bump electrode means, when adjacent bumps A and B are present, the distance between the end of bump A on the bump B side and the end of bump B on the bump A side.

[0055] The metal species constituting the bump electrode is not particularly limited, and examples thereof include solder, silver, gold, copper, tin, lead, bismuth, and alloys thereof. These metal species may be used alone or in combination of two or more.

[0056] <Step (B)> The method for manufacturing an electronic device according to this embodiment includes a step (B) of flattening the SA surface of the backgrinding tape 100 in the structure 500. The step (B) is performed after the step (A). An optional step may be included between the step (A) and the step (B).

[0057] After step (A), irregularities may occur on the SA surface of the backgrinding tape 100 in the structure 500. Step (B) is a step of smoothing out the irregularities that have occurred on the SA surface of the backgrinding tape 100.

[0058] In step (B), the method for flattening the SA surface of the backgrind tape 100 is not particularly limited, and may be appropriately selected depending on the depth of the concave portions (height of the convex portions) of the unevenness generated on the SA surface, and examples thereof include a method for flattening the SA surface by grinding, a method for flattening the SA surface by polishing, and a method for flattening the SA surface by cutting, and among these, a method for flattening the SA surface by grinding is preferred. In step (B), the specific method for flattening the SA surface of the backgrind tape 100 is not particularly limited, and may be appropriately selected, for example, from known grinding methods, known polishing methods, known cutting methods, and the like.

[0059] <Step (C)> The method for manufacturing an electronic device according to the present embodiment includes step (C) of grinding surface 400B of electronic component 400 opposite to the circuit formation surface. Step (C) is performed after step (B). An optional step may be included between steps (B) and (C).

[0060] Step (C) is a step of thinning electronic component 400 to a predetermined thickness without damaging it. For example, structure 500 is fixed to a chuck table or the like of a grinding machine, and surface 400B of electronic component 400 opposite the circuit formation surface is ground.

[0061] In step (C), electronic component 400 is ground until its thickness is equal to or less than a desired thickness. The thickness of electronic component 400 before grinding is determined appropriately depending on the diameter, type, etc. of electronic component 400, and the thickness of electronic component 400 after grinding is determined appropriately depending on the size of the resulting chip, type of circuit, etc.

[0062] The grinding method in step (C) is not particularly limited, and for example, a known grinding method can be used. Grinding can be performed while cooling the electronic component 400 and the grindstone by pouring water over them. If necessary, a dry polishing step, which is a grinding method that does not use grinding water, can be performed at the end of the grinding step.

[0063] After grinding the surface 400B of the electronic component 400 opposite the circuit-forming surface, chemical etching may be performed as needed. Chemical etching is performed by immersing the electronic component 400 with the backgrind tape 100 attached in an etching solution selected from the group consisting of an acidic aqueous solution consisting of a single or mixed solution of hydrofluoric acid, nitric acid, sulfuric acid, acetic acid, etc.; and an alkaline aqueous solution such as a potassium hydroxide aqueous solution or a sodium hydroxide aqueous solution. Etching is performed for the purposes of removing distortion generated on the back surface of the electronic component 400, further thinning the electronic component 400, removing oxide films, etc., and pretreatment for forming electrodes on the back surface. The etching solution is appropriately selected depending on the purpose.

[0064] <Step (D)> The method for manufacturing an electronic device according to the present embodiment preferably further includes a step (D) of removing the backgrind tape 100 from the structure 500. The step (D) is performed after the step (C). An optional step may be included between the step (C) and the step (D).

[0065] In step (D), the method for removing the backgrind tape 100 from the structure 500 is not particularly limited, and may be performed manually or by a device called an automatic peeling machine. In step (D), the backgrind tape 100 may be heated as needed, and the heating temperature may be in the range of 50°C or higher and 120°C or lower, for example.

[0066] The surface of the electronic component 400 after the backgrinding tape 100 has been removed may be cleaned as necessary. Examples of cleaning methods include wet cleaning such as water cleaning or solvent cleaning, and dry cleaning such as plasma cleaning. In the case of wet cleaning, ultrasonic cleaning may be used in combination. The cleaning method may be selected appropriately depending on the degree of contamination on the surface of the electronic component 400.

[0067] <Other Steps> The method for manufacturing an electronic device according to this embodiment may include other steps in addition to those described above. Examples of other steps include any step that is generally performed in the manufacturing process of electronic components, such as a resist step, a developing step, an ashing step, a sputtering step, a dicing step, a die bonding step, a wire bonding step, a flip-chip connection step, a cure heating test step, a sealing step, and a reflow step.

[0068] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various other configurations can also be adopted.

[0069] The present invention is not limited to the above-described embodiment, and modifications and improvements within the scope of achieving the object of the present invention are included in the present invention.

[0070] EXAMPLES The present invention will be specifically explained below with reference to examples and comparative examples, but the present invention is not limited thereto.

[0071] [Raw materials] PE1: Ethylene-α-olefin copolymer (manufactured by Mitsui Chemicals, Inc., product name: TAFMER A-4090S) PE2: Ethylene-α-olefin copolymer (manufactured by Mitsui Chemicals, Inc., product name: TAFMER A-4070) EVA1: Ethylene-vinyl acetate copolymer (manufactured by Mitsui-Dow Polychemicals Co., Ltd., product name: Evaflex EV460) PET1: Polyethylene terephthalate film (manufactured by Toray Industries, Inc., product name: Lumirror #50-T83) LLDPE1: Low-density polyethylene (manufactured by Prime Polymer Co., Ltd., product name: Evolue SP2320)

[0072] <Preparation of Acrylic 1> Ethyl acrylate (49 parts by mass), 2-ethylhexyl acrylate (20 parts by mass), methyl acrylate (21 parts by mass), glycidyl methacrylate (10 parts by mass), and a benzoyl peroxide-based polymerization initiator (0.5 parts by mass) were reacted in toluene (65 parts by mass) and ethyl acetate (50 parts by mass) at 80° C. for 10 hours. After completion of the reaction, the solution was cooled, and xylene (25 parts by mass), acrylic acid (5 parts by mass), and tetradecyldimethylbenzylammonium chloride (0.5 parts by mass) were added thereto. The mixture was reacted at 85° C. for 32 hours while blowing air into it, yielding an acrylic solution.

[0073] To 100 parts by mass of the acrylic solution (solid content), a crosslinking agent (0.9 parts by mass), a photopolymerization initiator (6.9 parts by mass), and a polyfunctional acrylate (12 parts by mass) were added to obtain an acrylic adhesive solution. The obtained acrylic adhesive solution is referred to as Acrylic 1.

[0074] [Examples 1 and 2] The resin described in Resin Layer (A) in Table 1 was extrusion-molded to form a film having the thickness described in Resin Layer (A) in Table 1, to obtain backgrind tapes of Examples 1 and 2, respectively.

[0075] Comparative Example 1 A backgrind tape of Comparative Example 1 was obtained by forming a film of LLDPE1 on PET1 by extrusion molding to a thickness of 95 μm.

[0076] Comparative Example 2 Acrylic 1 was applied onto PET 1 and dried to form a resin layer (B) having a thickness of 120 μm, thereby obtaining a backgrind tape of Comparative Example 2.

[0077] [Comparative Example 3] EVA1 was extruded to form a film having a thickness of 120 μm. Next, Acrylic 1 was applied to the formed EVA1 film and dried to form a resin layer (B) having a thickness of 110 μm, thereby obtaining a backgrind tape of Comparative Example 3.

[0078] Comparative Example 4 A backgrind tape of Comparative Example 4 was obtained in the same manner as in Examples 1 and 2, except that the type of resin was changed.

[0079] [Measurement and Evaluation] <Measurement of Resin Density> The density of the resin [kg / m ３ ] was measured.

[0080] <Measurement of Vicat Softening Point of Resin> The Vicat softening point [°C] of the resin was measured in accordance with ASTM D 1525.

[0081] <Measurement of Backgrind Tape Embedding Amount> A silicon wafer having a groove M with a width of 50 μm and a depth of 70 μm was prepared. Next, the silicon wafer was heated to 90°C using a hot plate. With the groove M of the silicon wafer in contact with one side (SB side) of the backgrind tape, a φ7 mm compression disk terminal was set on a digital force gauge (manufactured by A&D Co., Ltd., product name: AD-4932A-50N) from the side (SA side) opposite the SB side of the backgrind tape, and a load of 30 N was applied for 30 seconds. The load was applied under the conditions of humidity: 50 RH% and atmosphere: air. After the load was applied, the silicon wafer with the backgrind tape attached was cooled to 23°C, and the backgrind tape was peeled off from the silicon wafer. The amount of deformation in the height direction of the area where the shape of the groove M was transferred on the SB side of the backgrind tape was measured using a shape analysis laser microscope (Keyence Corporation, product name: VK-X1000). The surface irregularities were measured, and the height of the convex portion was obtained from the profile. This height was used as the embedding amount [μm]. In measuring the embedding amount, the silicon wafer size was Φ200 mm, the silicon wafer thickness was 725 μm, and the backgrind tape size was 30 mm × 30 mm. The groove M was rectangular and formed across the wafer. That is, the groove M was 50 μm wide and 200 mm long (wafer diameter). The position of the groove M was the center of the silicon wafer surface, and the position where the Φ7 mm compression disk terminal was set was above the groove M.

[0082] <Evaluation of Grindability> The silicon wafer and the backgrind tape were bonded together so that the circuit-forming surface of the silicon wafer (height of the circuit-forming surface: 35 μm) was in contact with the SB side of the backgrind tape, thereby obtaining a structure in which the silicon wafer and the backgrind tape were bonded together. Next, the SA side of the backgrind tape of the obtained structure was ground using a tape grinder (manufactured by Disco Corporation, product name: DMG8762). The grindability was evaluated according to the following criteria: A: The SA side of the backgrind tape could be ground without any problems. B: The SA side of the backgrind tape was difficult to grind. C: The SA side of the backgrind tape could not be ground.

[0083] <Evaluation of Thickness Precision> After the evaluation of grindability, the structure was ground on the surface of the silicon wafer opposite to the circuit-formed surface using a wafer grinding machine (manufactured by Disco Corporation, product name: DGP8760). Next, the backgrinding tape was peeled off from the structure. The difference between the maximum and minimum thicknesses of the silicon wafer (TTV) was measured. Evaluation was made according to the following criteria: A: TTV is 5 μm or less. B: TTV is greater than 5 μm.

[0084] Here, the evaluation of grindability can be said to have been carried out by performing steps (A) and (B) in the manufacturing method of the electronic device of this embodiment, and the evaluation of thickness accuracy can be said to have been carried out by performing steps (C) and (D) in the manufacturing method of the electronic device of this embodiment.

[0085] In the [Measurement and Evaluation], the backgrind tapes in which the resin layer (A) and the resin layer (B) are laminated (i.e., Comparative Examples 1 to 3) were measured and evaluated with the resin layer (A) side as the SA side and the resin layer (B) side as the SB side.

[0086] The results of the measurements and evaluations are shown in Table 1.

[0087]

[0088] As can be seen from Table 1, the backgrinding tape of the example had good evaluation results for thickness accuracy. In other words, it can be seen that the backgrinding tape of this embodiment can improve the thickness accuracy of the obtained electronic component.

[0089] Furthermore, the backgrinding tapes of the examples were evaluated for good grinding properties. That is, it can be seen that the backgrinding tape of this embodiment can improve the performance balance between tape grinding properties and the thickness accuracy of the resulting electronic components.

[0090] This application claims priority based on Japanese Patent Application No. 2023-202453, filed November 30, 2023, the disclosure of which is incorporated herein by reference in its entirety.

[0091] 10 Resin layer (A) 100 Backgrinding tape SA SA side of backgrinding tape SB SB side of backgrinding tape 200 Silicon wafer 300 Compressed disk terminal M Groove M of silicon wafer H Amount of deformation in the height direction at the location where the shape of groove M is transferred 400 Electronic component 400A Circuit formation surface of electronic component 400B Surface opposite to the circuit formation surface of electronic component 500 Structure

Claims

1. A backgrind tape capable of protecting the circuit formation surface of an electronic component in a process of grinding the electronic component, the backgrind tape comprising a resin layer (A), the resin constituting the resin layer (A) having a Vicat softening point of 45°C or higher, and an embedding amount measured by the following method 1 of 10 μm or more. [Method 1] A silicon wafer having a groove M of 50 μm width and 70 μm depth is heated to 90°C, and while the groove M is in contact with one surface (SB surface) of the backgrind tape, a φ7 mm compression disk terminal is set on a digital force gauge from the surface (SA surface) of the backgrind tape opposite to the SB surface, and a load of 30 N is applied for 30 seconds. After the load is applied, the silicon wafer to which the backgrind tape is attached is cooled to 23°C, and the backgrind tape is peeled off from the silicon wafer. The amount of deformation in the height direction at the portion of the SB surface of the backgrind tape where the shape of the groove M is transferred is defined as the embedding amount.

2. The backgrind tape according to claim 1, wherein the ratio of said resin layer (A) in said backgrind tape is 65 volume % or more.

3. The backgrind tape according to claim 1 or 2, wherein the backgrind tape comprises a single resin layer (A).

4. The density of the resin constituting the resin layer (A) is 880 kg / m ３ The backgrind tape according to any one of claims 1 to 3.

5. A backgrind tape according to any one of claims 1 to 4, wherein the resin constituting the resin layer (A) comprises at least one selected from the group consisting of ethylene-α-olefin copolymer, ethylene-vinyl ester copolymer, low-density polyethylene, polyvinyl chloride, and propylene-α-olefin copolymer.

6. The backgrind tape according to any one of claims 1 to 5, wherein the backgrind tape does not include an adhesive layer, or the backgrind tape further includes an adhesive layer, and the thickness of the adhesive layer is less than 10 μm.

7. The backgrind tape according to any one of claims 1 to 6, wherein the thickness of the backgrind tape is 50 µm or more and 1000 µm or less.

8. The backgrind tape according to any one of claims 1 to 7, which can be used in a method for manufacturing an electronic device, which includes a step of flattening the surface of the backgrind tape prior to the step of grinding the electronic components.

9. A method for manufacturing an electronic device, comprising: a step (A) of preparing a structure comprising an electronic component having a circuit formation surface and a backgrind tape, the structure being formed by bonding the circuit formation surface of the electronic component to one surface (SB surface) of the backgrind tape; a step (B) of flattening a surface (SA surface) of the backgrind tape opposite the SB surface of the electronic component in the structure; and a step (C) of grinding the surface of the electronic component opposite the circuit formation surface after step (B), wherein the backgrind tape comprises a resin layer (A), the Vicat softening point of the resin constituting the resin layer (A) is 45°C or higher, and the embedding amount measured by method 2 below is 10 μm or more. [Method 2] A silicon wafer having a groove M of 50 μm width and 70 μm depth is heated to 90° C., and while the groove M is in contact with the SB surface of the backgrind tape, a φ7 mm compression disk terminal is set on a digital force gauge from the SA surface, and a load of 30 N is applied for 30 seconds. After the load is applied, the silicon wafer to which the backgrind tape is bonded is cooled to 23° C., and then the backgrind tape is peeled off from the silicon wafer. The amount of deformation in the height direction at the point on the SB surface of the backgrind tape where the shape of the groove M is transferred is defined as the embedding amount.

10. The method for manufacturing an electronic device according to claim 9, further comprising the step (D) of removing the backgrind tape from the structure after step (C).

11. The method for producing an electronic device according to claim 9 or 10, wherein the proportion of said resin layer (A) in said backgrind tape is 65 volume % or more.

12. The method for manufacturing an electronic device according to any one of claims 9 to 11, wherein the backgrind tape is made of a single layer of the resin layer (A).

13. The density of the resin constituting the resin layer (A) is 880 kg / m ３ The method for producing an electronic device according to any one of claims 9 to 12, wherein the method is as described above.

14. A method for producing an electronic device according to any one of claims 9 to 13, wherein the resin constituting the resin layer (A) includes at least one selected from the group consisting of ethylene-α-olefin copolymer, ethylene-vinyl ester copolymer, low-density polyethylene, polyvinyl chloride, and propylene-α-olefin copolymer.

15. The method for manufacturing an electronic device according to any one of claims 9 to 14, wherein the backgrind tape does not include an adhesive layer, or the backgrind tape further includes an adhesive layer, and the thickness of the adhesive layer is less than 10 μm.

16. The method for manufacturing an electronic device according to any one of claims 9 to 15, wherein the thickness of the backgrind tape is 50 μm or more and 1000 μm or less.

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