Pressure-sensitive adhesive sheet and method for producing electronic component or semiconductor device

Abstract

A pressure-sensitive adhesive sheet including a pressure-sensitive adhesive layer that catches elements separated from a holding substrate, wherein the pressure-sensitive adhesive layer has recesses and protrusions in the surface thereof and has a complex shear modulus at 23°C of 0.001-1.0 MPa.

Description

Adhesive sheet and method for manufacturing electronic components or semiconductor devices

[0001] The present invention relates to an adhesive sheet and an electronic component or a semiconductor device.

[0002] Elements used in electronic components or semiconductor devices are often obtained by forming a large number of elements at once. For example, semiconductor chips are obtained by dicing a semiconductor wafer attached to an adhesive. When mounting such semiconductor chips on a semiconductor device, the semiconductor chips are often transferred. For example, Patent Document 1 discloses a method of transferring a semiconductor chip by irradiating the semiconductor chip with a laser (laser lift-off method).

[0003] Japanese Patent Application Laid-Open No. 2021-141181

[0004] When elements are moved from a substrate before transfer to a substrate after transfer, the elements are held by the substrate after transfer. In recent years, miniaturization of semiconductor devices and elements has progressed, and misalignment of the transfer position may hinder further miniaturization, so it is necessary for the elements to be held firmly by the substrate after transfer. Meanwhile, the elements held by the substrate after transfer are picked up from the substrate after predetermined processing. Therefore, it is necessary for the elements to be held weakly by the substrate after transfer so that they can be easily picked up from the substrate after predetermined processing.

[0005] An object of the present invention is to provide a pressure-sensitive adhesive sheet that can change the element-holding properties.

[0006] After extensive research, the inventors discovered that the above problem could be solved by providing irregularities having a predetermined complex shear modulus on the surface of the adhesive sheet that holds the element. After further research, they completed the present invention.

[0007] That is, the present invention relates to the following [1] to

[11] . [1] A pressure-sensitive adhesive sheet including a pressure-sensitive adhesive layer for capturing an element separated from a holding substrate, wherein the pressure-sensitive adhesive layer has an uneven surface and a complex shear modulus of 0.001 MPa to 1.0 MPa at 23°C. [2] The pressure-sensitive adhesive sheet according to [1], wherein the pressure-sensitive adhesive layer has a plurality of convex portions on its surface that are spaced apart and defined by recesses, wherein the plurality of convex portions deform when pressed to capture the element, and the deformed plurality of convex portions return to their convex shape in response to an external stimulus. [3] The pressure-sensitive adhesive sheet according to [1] or [2], wherein the pressure-sensitive adhesive layer has a plurality of convex portions on its surface that are spaced apart and defined by recesses, wherein the height of the plurality of convex portions is 1 μm or more. [4] The pressure-sensitive adhesive sheet according to any of [1] to [3], wherein the pressure-sensitive adhesive layer is formed from a pressure-sensitive adhesive composition containing an energy ray-curable compound (B). [5] The pressure-sensitive adhesive sheet according to any one of [1] to [4], wherein the pressure-sensitive adhesive layer is formed from a pressure-sensitive adhesive composition containing an acrylic resin (A). [6] The pressure-sensitive adhesive sheet according to any one of [1] to [5], wherein the pressure-sensitive adhesive layer is formed from a pressure-sensitive adhesive composition containing an acrylic resin (A) and an energy ray-curable compound (B). [7] The pressure-sensitive adhesive sheet according to any one of [1] to [6], wherein the pressure-sensitive adhesive layer has, on its surface, a plurality of convex portions spaced apart and defined by recesses, and the pitch of the plurality of convex portions is 1 μm or more and 100 μm or less. [8] The pressure-sensitive adhesive layer has, on its surface, a plurality of convex portions spaced apart and defined by recesses, and the area of ​​each of the plurality of convex portions is 10 μm or more. ２ More than 2000μm ２[9] The adhesive sheet according to any one of [1] to [7], wherein the adhesive layer has on its surface a plurality of convex portions that are spaced apart and whose boundaries are defined by concave portions, and the ratio of the area occupied by the convex portions to the area of ​​the adhesive layer is 1% or more and 95% or less.

[10] The adhesive sheet according to any one of [1] to [9], wherein the adhesive layer is configured so that the ratio of the adhesive area between the adhesive layer and one of the elements to the area of ​​one of the elements is 1% or more and 95% or less.

[11] A method for manufacturing an electronic component or a semiconductor device, comprising: a step of separating an element attached to a holding substrate from the holding substrate by an external stimulus; a step of pressing the element separated from the holding substrate against the adhesive sheet according to any one of [1] to

[10] to deform a plurality of convex portions on the surface of the adhesive layer, the convex portions being bounded by concave portions and spaced apart from one another, thereby holding the element on the adhesive layer; and a step of restoring the deformed convex portions to a convex shape by an external stimulus, thereby promoting separation of the element from the adhesive sheet.

[0008] According to the present invention, it is possible to provide a pressure-sensitive adhesive sheet that can change the element-holding properties.

[0009] The accompanying drawings are incorporated in and constitute a part of the specification, illustrate embodiments of the present invention, and are used, together with the description thereof, to explain the principles of the present invention. A schematic diagram of an adhesive sheet according to one embodiment. A top view showing an example of unevenness possessed by an adhesive sheet. A top view showing an example of unevenness possessed by an adhesive sheet. A top view showing an example of unevenness possessed by an adhesive sheet. A cross-sectional view showing an example of unevenness possessed by an adhesive sheet. A cross-sectional view showing an example of unevenness possessed by an adhesive sheet. A cross-sectional view showing an example of unevenness possessed by an adhesive sheet. A flow chart of a method for manufacturing an electronic component or semiconductor device according to one embodiment. A schematic diagram illustrating separation and capture of an element. A schematic diagram illustrating separation and capture of an element. A schematic diagram illustrating separation and capture of an element. A schematic diagram illustrating holding of an element. A schematic diagram illustrating holding of an element. A schematic diagram illustrating restoration of a convex portion. A schematic diagram illustrating restoration of a convex portion. A schematic diagram of an adhesive sheet placed in an expanding device. A schematic diagram of an adhesive sheet placed in an expanding device.

[0010] Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the invention as claimed, and not all combinations of features described in the embodiments are necessarily essential to the invention. Two or more of the features described in the embodiments may be combined in any desired manner. Furthermore, the same reference numerals are used to designate identical or similar components, and redundant descriptions will be omitted.

[0011] (Definitions) In this specification, the mass average molecular weight (Mw) and number average molecular weight (Mn) are values ​​measured by size exclusion chromatography in terms of standard polystyrene, specifically, values ​​measured in accordance with JIS K7252-1: 2016. In addition, in this specification, "(meth)acrylic acid" is a term that refers to both "acrylic acid" and "methacrylic acid," and the same applies to other similar terms.

[0012] As used herein, the term "electronic component" encompasses all components used in electronics and electrical engineering, as well as all components constituting electronic devices. An "electronic component" may be formed from a semiconductor, a conductor, and / or an insulator, or a combination thereof. Examples of "electronic components" include active components (mainly formed from semiconductors, such as transistors, ICs, LSIs, VLSIs, diodes, light-emitting diodes, thyristors, three-terminal regulators, and image sensors), passive components (such as resistors, capacitors, speakers, coils, transformers, relays, piezoelectric elements, quartz oscillators, ceramic oscillators, and varistors), and structural components (such as wiring components, printed circuit boards, connectors, and switches). Furthermore, as used herein, the term "semiconductor device" refers to devices in general that can function by utilizing the properties of semiconductors, such as processors, memories, and sensors. Examples of "semiconductor device" include micro light-emitting diodes, mini light-emitting diodes, power devices, MEMS (Micro Electro Mechanical Systems), and controller chips.

[0013] In this specification, when one or more lower limit values ​​and one or more upper limit values ​​of a numerical range (e.g., a range of content, etc.) are described, it can be understood that any combination of the lower limit value and the upper limit value therein is described. For example, the description of 1 or more, 2 or more, 3 or more, and 9 or less, 8 or less, 7 or less clearly means that the numerical range may be any of 1 or more and 9 or less, 1 or more and 8 or less, 1 or more and 7 or less, 2 or more and 9 or less, 2 or more and 8 or less, 2 or more and 7 or less, 3 or more and 9 or less, 3 or more and 8 or less, and 3 or more and 7 or less.

[0014] <<Adhesive Sheet According to the Present Embodiment>> The adhesive sheet according to the present embodiment comprises an adhesive layer that captures elements separated from a holding substrate, and the adhesive layer has an uneven surface. FIG. 1 shows a schematic diagram of an adhesive sheet according to an embodiment. In one embodiment, the adhesive sheet may comprise an adhesive layer 110 and a substrate 120. However, it is not essential that the adhesive sheet have the substrate 120. For example, the adhesive sheet may be composed of only the adhesive layer 110. In this case, an adhesive layer 110 with high support can be used. Each component of the adhesive sheet will be described below.

[0015] <Adhesive Layer> The adhesive layer 110 according to this embodiment is a layer having adhesive properties and may contain a resin. As described above, the surface of the adhesive layer 110 has irregularities. The adhesive sheet may have two or more adhesive layers 110. For example, the adhesive sheet may have a laminate of one type of adhesive layer 110, or two or more types of adhesive layers 110.

[0016] (Complex Shear Modulus) The adhesive layer 110 according to this embodiment has a complex shear modulus of 0.001 MPa or more and 1.0 MPa or less at 23°C. The complex shear modulus can be preferably 1.0 MPa or less, more preferably 0.8 MPa or less, even more preferably 0.6 MPa or less, and particularly preferably 0.3 MPa or less. This allows the convex portions to be pressed against the element and deformed and crushed when the element is held on the adhesive sheet. Furthermore, as the convex portions are deformed and crushed, the concave portions of the adhesive layer 110 rise, and the convex portions and the concave portions come into contact with the element. This allows the element and the adhesive layer 110 to be in planar contact, thereby firmly holding the element to the adhesive layer 110.

[0017] The complex shear modulus can be preferably 0.001 MPa or more, more preferably 0.01 MPa or more, even more preferably 0.05 MPa or more, and particularly preferably 0.1 MPa or more. As a result, when the element is picked up from the adhesive sheet, an external stimulus is applied to the adhesive sheet, and the deformed convex portions can be restored to their convex shape. Furthermore, as the deformed convex portions are restored to their convex shape, the deformed concave portions are restored to their concave shape, and the convex portions and the element come into point contact, so the element is weakly held by the adhesive layer 110. As a result, the element can be easily picked up from the adhesive sheet.

[0018] The range of the complex shear modulus is preferably 0.001 MPa to 1.0 MPa, more preferably 0.01 MPa to 0.8 MPa, even more preferably 0.05 MPa to 0.6 MPa, and particularly preferably 0.1 MPa to 0.3 MPa. This allows the pressure-sensitive adhesive sheet according to this embodiment to change the element retention properties.

[0019] The complex shear modulus of the adhesive layer 110 can be confirmed, for example, as follows: A sample having a diameter of 8 mm and a thickness of 1 mm is prepared, and the complex shear modulus of the sample is measured at 23° C. using a viscoelasticity measuring device by a torsional shear method at a frequency of 1 Hz, thereby measuring the complex shear modulus of the adhesive layer 110. A more specific method for measuring the complex shear modulus will be described in the Examples.

[0020] (Shape) The surface of the adhesive layer 110 has irregularities. If the surface of the adhesive layer 110 has irregularities with a predetermined complex shear modulus, it is possible to change the holding power that occurs between the element and the adhesive layer 110. Therefore, the specific shape of the irregularities that the surface of the adhesive layer 110 has is not limited.

[0021] In one embodiment, the adhesive layer 110 has a plurality of spaced apart protrusions on its surface, bounded by recesses. Each of the plurality of protrusions may be separated by a continuous recess throughout the adhesive layer 110. By providing a continuous recess around such protrusions, the retention of the device can be modified.

[0022] On the other hand, gas compressed between the element and the adhesive layer 110 due to the element approaching the adhesive layer 110 can escape into the recesses in the adhesive sheet, thereby relieving the pressure generated between the element and the adhesive layer 110. Therefore, the pressure generated between the element and the adhesive layer 110 can prevent the element from being misaligned on the adhesive sheet. In one embodiment, the recesses located around each of the multiple protrusions are continuous to the edge of the adhesive layer 110. By providing recesses that are continuous to the edge of the adhesive layer 110 in this way, gas compressed between the element and the protrusions of the adhesive layer 110 can be efficiently released to the outside of the element. Figures 2A to 2C are top views showing the shape of such an adhesive layer 110.

[0023] As shown in FIG. 2A , protrusions 111 may be regularly arranged on the surface of the adhesive layer 110. Regularly arranging the protrusions 111 means that the protrusions 111 are arranged in a straight line at regular intervals. Alternatively, as shown in FIG. 2B , the protrusions 111 may be arranged so that the intervals between them vary regularly. In the example of FIG. 2B , the intervals between the protrusions 111 are short at the center of the adhesive sheet and long at the periphery of the adhesive sheet. This configuration improves the retention of the adhesive sheet while allowing compressed gas to efficiently escape from the periphery of the element via wider recesses. Furthermore, the protrusions 111 may be irregularly arranged.

[0024] 2C is a top view showing another shape of the adhesive layer 110. As shown in FIG. 2C, stripe-shaped protrusions 111 may be provided on the surface of the adhesive layer 110. In FIG. 2C, linear protrusions 111 having a constant width are arranged at regular intervals. On the other hand, as in FIG. 2B, the width or interval of the linear protrusions 111 may vary regularly, or the linear protrusions 111 may be arranged irregularly.

[0025] 2B , the smallest interval among all the intervals between all the convex portions 111 in the center of the adhesive sheet may be shorter than the smallest interval among all the intervals between all the convex portions 111 in the peripheral portion of the adhesive sheet. Here, the central portion refers to, for example, a circular region having ¼ of the area of ​​the adhesive sheet and centered on the center of gravity of the adhesive sheet, and the peripheral portion refers to, for example, the entire region of the adhesive sheet other than the central portion.

[0026] The pitch P of the convex portions 111 is preferably 1 μm or more, more preferably 5 μm or more, even more preferably 10 μm or more, and particularly preferably 15 μm or more, from the viewpoint of adjusting the holding power. On the other hand, from the viewpoint of increasing the contact area between the adhesive layer 110 and the element and enhancing the holding power, this pitch is preferably 100 μm or less, more preferably 75 μm or less, more preferably 50 μm or less, even more preferably 35 μm or less, and particularly preferably 25 μm or less. Here, the pitch of the convex portions 111 refers to the distance between the center point of an arbitrarily selected convex portion 111 and the center point of another convex portion 111 closest to that convex portion 111. For example, in the case of FIG. 2A, the pitch of the convex portions 111 represents the distance between the center point of the convex portion 111 on a straight line on which the convex portions 111 are arranged at regular intervals and the center point of another convex portion 111' closest to that convex portion 111. When the convex portions 111 are arranged on a plurality of straight lines, the pitch represents the distance between the center points of the convex portions on the line arranged at the shortest pitch. Also, when the convex portions have an elongated shape as shown in Figure 2C and the center points of the convex portions are difficult to identify, the pitch represents the distance from the boundary of the convex portion 111 on the same side to the boundary of the nearest other convex portion 111'.

[0027] The specific shape of the protrusions 111 is not particularly limited. For example, the protrusions 111 may have a pillar (column) shape. As a specific example, the protrusions 111 may have a cylindrical shape or a prismatic shape. Furthermore, as described above, the protrusions 111 may extend in a line shape, or may extend in a curved shape such as a wavy shape. Furthermore, these protrusions 111 may be tapered.

[0028] 3A shows a cross-sectional view of an adhesive layer 110 according to one embodiment, taken perpendicular to the surface of the adhesive layer 110 and passing through a protruding portion 111. The protruding portion 111 shown in FIG. 3A is tapered, i.e., the protruding portion 111 is tapered. As shown in FIG. 3A, the surface of the adhesive layer 110 may have flat recesses and protruding portions 111 protruding from the recesses. In this way, the adhesive layer 110 has a plurality of protruding portions 111 that are spaced apart from one another, and the boundaries of the recesses may be defined by the recesses.

[0029] 3B, the tip of the convex portion 111 may be hemispherical or have a curved surface like a part of a sphere. With this configuration, the impact when the element separated from the holding substrate comes into contact with the adhesive layer 110 is further reduced, making it easier for the adhesive layer 110 to capture the element so that it does not slip. On the other hand, the tip of the convex portion may be flat.

[0030] 3C , the protrusions 111 may be T-shaped. As yet another example, the protrusions 111 may have a shape of a collection of particles, a mushroom shape, the surface of a lotus leaf, or a needle shape. As yet another example, the surface of the adhesive layer 110 may be rough or fibrous, and such a surface may also be said to have unevenness.

[0031] The width or diameter of each protrusion 111 is the width or diameter of its base, not its tip, and is preferably 1 μm or more, more preferably 2 μm or more, even more preferably 5 μm or more, and particularly preferably 10 μm or more. On the other hand, it is preferably 100 μm or less, more preferably 50 μm or less, even more preferably 30 μm or less, and particularly preferably 20 μm or less. This allows the retention of the element to be changed. Here, the width and diameter of the protrusion 111 refer to the minimum and maximum distances (represented by D in FIG. 3A ) between two parallel lines that contact the protrusion 111 from both sides on the surface of the recess.

[0032] The area of ​​each of the protrusions 111 is preferably 10 μm ２ More preferably, 20 μm or more ２ More preferably, 30 μm or more ２ On the other hand, preferably, 2000 μm ２ Less than 1000 μm, more preferably ２ More preferably, 500 μm or less ２ Here, the area of ​​the convex portion 111 means the area of ​​the portion protruding from the surface of the concave portion (the area of ​​a circle with a diameter D in the case of FIG. 3A).

[0033] Furthermore, the height of each of the protrusions 111 is preferably 1 μm or more, more preferably 3 μm or more, and even more preferably 5 μm or more. On the other hand, the height of each of the protrusions 111 is preferably 20 μm or less, more preferably 15 μm or less, and even more preferably 10 μm or less. This makes it possible to change the retention properties of the element. Here, the height of the protrusions 111 is represented by H in FIG. 3A.

[0034] Furthermore, the area of ​​each protrusion 111 relative to the area of ​​the adhesive layer 110 is preferably 1% or more, more preferably 5% or more, more preferably 10% or more, even more preferably 18% or more, and particularly preferably 40% or more. On the other hand, the area of ​​each protrusion relative to the area of ​​the adhesive layer 110 is preferably 95% or less, more preferably 75% or less, and even more preferably 60% or less. This makes it possible to change the retention property for the element.

[0035] The unevenness of the adhesive layer 110 may be designed according to the shape of the element held by the adhesive sheet. For example, the ratio of the adhesion area between the adhesive layer 110 and one element to the area of ​​one element is preferably 1% or more, more preferably 2% or more, more preferably 3% or more, more preferably 4% or more, more preferably 5% or more, even more preferably 7% or more, and particularly preferably 10% or more, relative to 100% of the area of ​​one element. On the other hand, the ratio of the adhesion area between the adhesive layer 110 and one element to the area of ​​one element is preferably 95% or less, more preferably 70% or less, even more preferably 50% or less, and particularly preferably 30% or less. In the case of FIG. 3A, the adhesion area corresponds to the area of ​​a circle with a diameter T. Note that the adhesion area may change if the capture position of the element on the adhesive sheet is shifted. In this case, the adhesion area ratio may fall within the above range regardless of the capture position of the element.

[0036] (Composition of Adhesive Layer (Adhesive Composition)) The adhesive composition forming the adhesive layer 110 contains a resin. Examples of resins contained in the adhesive composition include rubber-based resins such as polyisobutylene-based resins, polybutadiene-based resins, and styrene-butadiene-based resins, acrylic-based resins, urethane-based resins, polyester-based resins, olefin-based resins, silicone-based resins, and polyvinyl ether-based resins. The adhesive layer may also be heat-resistant, and examples of heat-resistant adhesive layer materials include polyimide-based resins and silicone-based resins. The adhesive composition forming the adhesive layer 110 may contain a copolymer having two or more types of structural units. The form of such a copolymer is not particularly limited, and may be any of a block copolymer, a random copolymer, an alternating copolymer, and a graft copolymer. The resin contained in the adhesive composition forming the adhesive layer 110 may be composed of one type of resin, or two or more types of resins.

[0037] The resin contained in the adhesive composition forming the adhesive layer 110 can be an adhesive resin that exhibits adhesive properties by itself. The resin can be a polymer having a mass-average molecular weight (Mw) of 10,000 or more. From the viewpoint of improving adhesive strength, the mass-average molecular weight (Mw) of the resin is preferably 10,000 or more, more preferably 70,000 or more, and even more preferably 140,000 or more. From the viewpoint of suppressing the complex shear modulus to a predetermined value or less, the mass-average molecular weight (Mw) of the resin is preferably 2,000,000 or less, more preferably 1,200,000 or less, and even more preferably 900,000 or less. From the viewpoint of improving adhesive strength, the number-average molecular weight (Mn) of the resin is preferably 10,000 or more, more preferably 50,000 or more, and even more preferably 100,000 or more. From the viewpoint of suppressing the complex shear modulus to a predetermined value or less ...2,000,000 or less, more preferably 1,000,000 or less, and even more preferably 700,000 or less. As described below, when the adhesive layer 110 contains a resin derived from an energy ray-curable resin, the mass average molecular weight (Mw) and number average molecular weight (Mn) refer to the mass average molecular weight (Mw) and number average molecular weight (Mn) before the crosslinking reaction due to energy application.

[0038] The glass transition temperature (Tg) of the resin is preferably −75° C. or higher, more preferably −70° C. or higher, and preferably −10° C. or lower, more preferably −20° C. or lower. When Tg is within this range, the complex shear modulus of the resulting adhesive layer is easily set within the range described below.

[0039] The amount of resin relative to the total amount of components constituting the adhesive composition forming the adhesive layer 110 can be set appropriately depending on the desired adhesive strength and complex shear modulus of the adhesive layer 110, but is preferably 30% by mass or more, more preferably 40% by mass or more, more preferably 50% by mass or more, even more preferably 55% by mass or more, and particularly preferably 60% by mass or more, and is preferably 99.99% by mass or less, more preferably 99.95% by mass or less, and even more preferably 99.90% by mass or less.

[0040] Thermoplastic Resin In one embodiment, the resin contained in the adhesive composition forming the adhesive layer 110 may include a thermoplastic resin. That is, the adhesive layer 110 can be formed from a thermoplastic resin. When a thermoplastic resin is used, it is easy to form irregularities in the adhesive layer 110 by heating the resin to soften it, and it is also easy to maintain the irregular shape formed by cooling the resin. Examples of thermoplastic resins include rubber-based resins, acrylic-based resins, urethane-based resins, and olefin-based resins. Examples include polybutadiene-based thermoplastic elastomers using butadiene as a monomer, styrene-based thermoplastic elastomers using styrene as a monomer, and acrylic-based thermoplastic elastomers using (meth)acrylic acid esters as a monomer.

[0041] Acrylic Resin (A) In one embodiment, the thermoplastic resin may be an acrylic resin (A). From the viewpoint of improving adhesive strength, the mass average molecular weight (Mw) of the acrylic resin (A) is preferably 10,000 or more, more preferably 100,000 or more, and even more preferably 500,000 or more. Furthermore, from the viewpoint of suppressing the complex shear modulus to a predetermined value or less, the mass average molecular weight (Mw) is preferably 2,000,000 or less, more preferably 1,500,000 or less, and even more preferably 1,000,000 or less.

[0042] The glass transition temperature (Tg) of the acrylic resin (A) is preferably −75° C. or higher, more preferably −70° C. or higher, and preferably 5° C. or lower, more preferably −25° C. or lower, and even more preferably −55° C. or lower. When the Tg is within this range, the complex shear modulus of the resulting pressure-sensitive adhesive can be easily adjusted to fall within this range.

[0043] When the acrylic resin (A) has two or more structural units, the glass transition temperature (Tg) of the acrylic resin (A) can be calculated using the Fox equation. The Tg of the monomer from which the structural unit is derived can be determined from the value listed in the Polymer Data Handbook or the Adhesive Handbook.

[0044] Examples of the (meth)acrylic acid ester constituting the acrylic resin (A) include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, (meth)acrylate, n-octyl (meth)acrylate, n-nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, myristyl (meth)acrylate, pentadecyl (meth)acrylate, palmityl (meth)acrylate, heptadecyl (meth)acrylate, stearyl (meth)acrylate, etc., in which the alkyl group constituting the alkyl ester has a chain structure having 1 to 18 carbon atoms ( (meth)acrylic acid alkyl esters; (meth)acrylic acid cycloalkyl esters such as isobornyl (meth)acrylate and dicyclopentanyl (meth)acrylate; (meth)acrylic acid aralkyl esters such as benzyl (meth)acrylate; (meth)acrylic acid cycloalkenyl esters such as dicyclopentenyl (meth)acrylate; (meth)acrylic acid cycloalkenyloxyalkyl esters such as dicyclopentenyloxyethyl (meth)acrylate; imide (meth)acrylates; glycidyl (meth)acrylate, etc. Examples of the hydroxyl group-containing (meth)acrylic acid ester include glycidyl group-containing (meth)acrylic acid esters; hydroxyl group-containing (meth)acrylic acid esters such as hydroxymethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; and substituted amino group-containing (meth)acrylic acid esters such as N-methylaminoethyl (meth)acrylate.Here, the term "substituted amino group" refers to a group having a structure in which one or two hydrogen atoms of an amino group are substituted with a group other than a hydrogen atom.

[0045] The acrylic resin (A) may be, for example, a resin obtained by copolymerizing one or more monomers selected from (meth)acrylic acid ester, (meth)acrylic acid, itaconic acid, vinyl acetate, acrylonitrile, styrene, N-methylolacrylamide, and the like.

[0046] The acrylic resin (A) may be composed of one kind of monomer or two or more kinds of monomers, and when two or more kinds of monomers are used, the combination and ratio thereof can be selected arbitrarily.

[0047] The acrylic resin (A) may have, in addition to a hydroxyl group, a functional group capable of bonding to other compounds, such as a vinyl group, a (meth)acryloyl group, an amino group, a carboxy group, an isocyanate group, etc. These functional groups, including the hydroxyl group of the acrylic resin (A), may bond to other compounds via a crosslinking agent (C) described below, or may bond directly to other compounds without the crosslinking agent (C).

[0048] The amount of the acrylic resin (A) in the total amount of resin in the pressure-sensitive adhesive composition can be set appropriately depending on the desired adhesive strength and complex shear modulus of the pressure-sensitive adhesive layer 110, but is preferably 0% by mass or more, more preferably 10% by mass or more, even more preferably 20% by mass or more, particularly preferably 50% by mass or more, and is preferably 100% by mass or less, more preferably 95% by mass or less.

[0049] Energy ray curable resin (B) In one embodiment, the resin contained in the pressure-sensitive adhesive composition forming the pressure-sensitive adhesive layer 110 may contain an energy ray curable resin (B). "Energy ray curable" refers to the property of being cured by irradiation with energy rays, and energy ray curable resin (B) refers to a resin that is cured by irradiation with energy rays. Furthermore, "energy rays" refers to electromagnetic waves or charged particle beams that have an energy quantum, and examples thereof include ultraviolet rays, radioactive rays, and electron beams. Ultraviolet rays can be irradiated using, for example, an electrodeless lamp, a high-pressure mercury lamp, a metal halide lamp, a UV-LED, or the like as an ultraviolet light source. Electron beams generated by an electron beam accelerator or the like can be irradiated. Furthermore, "energy ray polymerizable" refers to the property of being polymerized by irradiation with energy rays.

[0050] When such an energy ray-curable resin (B) is used, by imparting energy (for example, by irradiating with energy rays) after forming the irregularities in the resin, it becomes easy to maintain the formed irregularities.

[0051] The energy ray-curable resin (B) may be a monomer, oligomer, or polymer having a polymerizable functional group introduced therein. The polymerizable functional group is a functional group that crosslinks upon application of energy (e.g., irradiation with energy rays). Examples of the polymerizable functional group include a vinyl group, an alkenyl group such as an allyl group, a (meth)acryloyl group, an oxetanyl group, and an epoxy group.

[0052] The mass average molecular weight (Mw) of the energy ray curable resin (B) is preferably 100 or more, more preferably 150 or more, from the viewpoint of improving adhesive strength. Furthermore, from the viewpoint of suppressing the complex shear modulus to a predetermined value or less, it is preferably 2 million or less, more preferably 1 million or less, and even more preferably 200,000 or less. When a monomer or oligomer is used as the energy ray curable resin (B), the number average molecular weight (Mn) of the energy ray curable resin (B) is preferably 100 or more, more preferably 150 or more, from the viewpoint of polymerizability. Furthermore, from the viewpoint of suppressing the complex shear modulus to a predetermined value or less, it is preferably 5,000 or less, more preferably 1,000 or less, and even more preferably 500 or less. When a polymer is used as the energy ray curable resin (B), the mass average molecular weight (Mw) of the energy ray curable resin (B) is preferably 10,000 or more, more preferably 50,000 or more, and even more preferably 100,000 or more, from the viewpoint of improving adhesive strength. Moreover, from the viewpoint of suppressing the complex shear modulus to a predetermined value or less, it is preferably 2,000,000 or less, more preferably 500,000 or less, and even more preferably 300,000 or less.

[0053] From the viewpoint of easily maintaining the uneven shape of the pressure-sensitive adhesive layer, the average number of polymerizable functional groups per molecule in the energy ray-curable resin (B) is preferably 1.5 or more, more preferably 2 or more. On the other hand, from the viewpoint of improving the adhesiveness and flexibility of the pressure-sensitive adhesive layer, this average number is preferably 20 or less, more preferably 15 or less, and even more preferably 10 or less.

[0054] In one embodiment, the energy ray-curable resin (B) may be a monomer or oligomer having a polymerizable functional group. Examples of such energy ray-curable compounds include polyvalent (meth)acrylate monomers such as glycerin di(meth)acrylate, glycerin tri(meth)acrylate, 1,4-butylene glycol di(meth)acrylate, 1,6-hexanediol (meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol (meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and tricyclodecane dimethanol di(meth)acrylate; urethane (meth)acrylate; polyester (meth)acrylate; polyether (meth)acrylate; and epoxy (meth)acrylate. Among these, from the viewpoint of maintaining the formed uneven shape, preferred are glycerin di(meth)acrylate, glycerin tri(meth)acrylate, and tricyclodecane dimethanol di(meth)acrylate.

[0055] In one embodiment, the energy ray-curable resin (B) can be a diene-based rubber composed of a polymer having a polymerizable functional group at the end of the main chain and / or in the side chain. Diene-based rubber refers to a rubbery polymer having a double bond in the polymer main chain. Specific examples of diene-based rubbers include polymers using butadiene or isoprene as a monomer (i.e., having butenediyl groups or pentenediyl groups as structural units). In one embodiment, the energy ray-curable resin (B) can be a polybutadiene resin (PB resin), a styrene-butadiene-styrene block copolymer (SBS resin), or a styrene-isoprene-styrene block copolymer.

[0056] The amount of the energy ray curable resin (B) in the total amount of resin in the adhesive composition can be set appropriately depending on the desired adhesive strength and complex shear modulus of the adhesive layer 110, but is preferably 0 mass% or more, more preferably 10 mass% or more, even more preferably 20 mass% or more, particularly preferably 50 mass% or more, and is preferably 100 mass% or less, more preferably 95 mass% or less, even more preferably 80 mass% or less, particularly preferably 60 mass% or less.

[0057] In one embodiment, the pressure-sensitive adhesive composition may contain an acrylic resin (A) and an energy ray-curable resin (B). The relationship between the contents of the acrylic resin (A) and the energy ray-curable resin (B) can be appropriately set depending on the desired adhesive strength and complex shear modulus of the pressure-sensitive adhesive layer 110. In one embodiment, the content of the acrylic resin (A) in the total content of the acrylic resin (A) and the energy ray-curable resin (B) is preferably 0% by mass or more, more preferably 10% by mass or more, even more preferably 20% by mass or more, particularly preferably 50% by mass or more, and preferably 100% by mass or less, more preferably 95% by mass or less.

[0058] The adhesive composition forming the adhesive layer 110 may contain components other than resin. For example, the adhesive composition may contain one or more of a crosslinking agent (C), a photopolymerization initiator (D), an antioxidant (E), and other additives.

[0059] Crosslinking Agent (C) The pressure-sensitive adhesive composition may contain a crosslinking agent (C) for bonding functional groups of the resin with other compounds to effect crosslinking. Examples of the crosslinking agent (C) include isocyanate-based crosslinking agents (crosslinking agents having an isocyanate group) such as tolylene diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, and adducts of these diisocyanates, epoxy-based crosslinking agents (crosslinking agents having a glycidyl group) such as ethylene glycol glycidyl ether, aziridine-based crosslinking agents (crosslinking agents having an aziridinyl group) such as hexa[1-(2-methyl)-aziridinyl]triphosphatriazine, metal chelate-based crosslinking agents (crosslinking agents having a metal chelate structure) such as aluminum chelate, and isocyanurate-based crosslinking agents (crosslinking agents having an isocyanuric acid skeleton).

[0060] The pressure-sensitive adhesive composition may contain one type of crosslinking agent or may contain two or more types of crosslinking agents. From the viewpoint of appropriately carrying out the crosslinking reaction, the content of the crosslinking agent (C) in the pressure-sensitive adhesive composition is preferably 0.01 mass% or more, more preferably 0.1 mass% or more, even more preferably 1 mass% or more, and is preferably 5 mass% or less, more preferably 4 mass% or less, even more preferably 2 mass% or less.

[0061] Photopolymerization initiator (D) The pressure-sensitive adhesive composition may contain a photopolymerization initiator (D) that initiates a crosslinking reaction in response to the application of energy (e.g., irradiation with energy rays). When the pressure-sensitive adhesive composition contains the energy ray-curable resin (B), the pressure-sensitive adhesive layer 110 further contains the photopolymerization initiator (D), and thus the crosslinking reaction proceeds even when a relatively low amount of energy is applied.

[0062] Examples of the photopolymerization initiator (D) include 1-hydroxycyclohexyl phenyl ketone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzyl phenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, dibenzyl, diacetyl, 8-chloroanthraquinone, and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide.

[0063] The pressure-sensitive adhesive composition may contain one type of polymerization initiator or two or more types of polymerization initiators. The content of the photopolymerization initiator (D) in the pressure-sensitive adhesive composition is preferably 0.01 mass% or more, more preferably 0.1 mass% or more, even more preferably 1 mass% or more, and is preferably 10 mass% or less, more preferably 5 mass% or less, even more preferably 2 mass% or less.

[0064] Antioxidant (E) The pressure-sensitive adhesive composition may contain an antioxidant (E). Examples of the antioxidant (E) include phenol-based antioxidants such as hindered phenol-based compounds, aromatic amine-based antioxidants, sulfur-based antioxidants, and phosphorus-based antioxidants such as phosphate ester-based compounds.

[0065] Furthermore, the adhesive composition forming the adhesive layer 110 may contain one or more of an ultraviolet absorber, a light stabilizer, a resin stabilizer, a filler, a pigment, an extender, a softener, and the like.

[0066] <Substrate> The substrate 120 included in the pressure-sensitive adhesive sheet according to this embodiment functions as a support for supporting the pressure-sensitive adhesive layer 110. The type of substrate 120 is not particularly limited, and may be a hard substrate or a flexible substrate. The substrate 120 may be a flexible substrate from the viewpoints of improving cushioning properties when capturing an element, facilitating attachment to other members, improving peelability, facilitating lamination, or enabling formation into a roll form. For example, a resin film may be used as the substrate 120.

[0067] The resin film is a film that uses a resin-based material as a main material, and may be made of a resin material alone or may contain an additive in addition to a resin material. The resin film may be laser beam transmissive.

[0068] Specific examples of resin films include polyethylene films such as low-density polyethylene film, linear low-density polyethylene film, and high-density polyethylene film; polyolefin films such as polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, ethylene-norbornene copolymer film, and norbornene resin film; ethylene copolymer films such as ethylene-vinyl acetate copolymer film, ethylene-(meth)acrylic acid copolymer film, and ethylene-(meth)acrylic acid ester copolymer film; polyvinyl chloride films such as polyvinyl chloride film and vinyl chloride copolymer film; polyester films such as polyethylene terephthalate film and polybutylene terephthalate film; polyurethane film; polyimide film; polystyrene film; polycarbonate film; and fluororesin films. Films containing a mixture of two or more materials, crosslinked films in which the resins forming these films are crosslinked, and modified films such as ionomer films may also be used. The substrate 120 may also be a laminate film in which two or more resin films are laminated.

[0069] From the viewpoints of versatility, relatively high strength that makes it easy to prevent warping, and heat resistance, the resin film may be a single-layer film selected from the group consisting of polyethylene films, polyester films, and polypropylene films, or a laminate film in which two or more types of films selected from this group are laminated.

[0070] The thickness of the substrate 120 is not particularly limited, but from the viewpoint of achieving both supportability and roll winding property, it can be preferably 10 μm or more, more preferably 25 μm or more, even more preferably 40 μm or more, preferably 500 μm or less, more preferably 200 μm or less, and even more preferably 90 μm or less. The thickness of the substrate 120 can be preferably in the range of 10 μm or more and 500 μm or less, preferably 25 μm or more and 200 μm or less, and even more preferably 40 μm or more and 90 μm or less.

[0071] <Other Layers> The adhesive sheet may have layers other than the substrate 120 and the adhesive layer 110. For example, an additional adhesive layer may be provided on the surface of the substrate 120 opposite the adhesive layer 110. The adhesive sheet can be attached to another substrate such as quartz glass via such an adhesive layer. The type of the additional adhesive layer is not particularly limited, and the additional adhesive layer can be formed using, for example, a general adhesive.

[0072] <Method for manufacturing adhesive sheet> There are no particular limitations on the method for manufacturing an adhesive sheet. For example, an adhesive sheet having an adhesive layer 110 provided on a substrate 120 can be manufactured as follows. First, an organic solvent is added to the adhesive composition that forms the adhesive layer 110 described above to prepare a solution of the adhesive composition. This solution is then applied to the substrate to form a coating film, which is then dried, thereby providing an adhesive layer on the substrate 120. Furthermore, by performing a process to provide irregularities on the surface of this adhesive layer, an adhesive layer 110 having irregularities can be formed.

[0073] Examples of organic solvents used to prepare a solution of the pressure-sensitive adhesive composition include toluene, ethyl acetate, and methyl ethyl ketone. Examples of methods for applying the solution include spin coating, spray coating, bar coating, knife coating, roll coating, roll knife coating, blade coating, die coating, gravure coating, and printing methods (e.g., screen printing and inkjet printing).

[0074] There are no particular limitations on the process for providing the surface of the adhesive layer with irregularities. For example, irregularities can be provided on the surface of the adhesive layer using an imprinting method. In the imprinting method, a mold having a surface shape complementary to the irregularities to be provided can be used. Specifically, irregularities can be provided on the surface of the adhesive layer by heating the adhesive layer while pressing the adhesive layer provided on the substrate with the mold. A more specific method involves pressing the adhesive layer with the mold, heating the adhesive layer, and maintaining the temperature for a predetermined period of time, after which the adhesive layer is cooled and the mold is removed. When heating the adhesive layer, for example, the adhesive layer can be heated to a temperature higher than the softening point of the adhesive layer. The time for maintaining the adhesive layer in the heated state is also not particularly limited, and may be maintained for, for example, 10 seconds or more or 10 minutes or less. A specific method for heating the adhesive layer while pressing the adhesive layer with the mold includes vacuum laminating the adhesive layer provided on the substrate and the mold. Instead of performing the two-stage process of forming the adhesive layer and forming the irregularities, the adhesive layer 110 having irregularities on its surface may be formed on the substrate in a single stage.

[0075] As another method, the adhesive layer 110 having a textured shape can be provided by spray-coating a solution of the adhesive composition. Furthermore, the adhesive layer 110 having a rough or fibrous surface can be provided by adding a filler to a solution of the adhesive composition and coating such a solution. As yet another method, the adhesive layer having a textured shape can be directly provided on a substrate by coating a solution of the adhesive composition according to a desired pattern using a printing method such as an inkjet method.

[0076] Furthermore, a pressure-sensitive adhesive sheet that does not have a substrate 120 can be produced by forming a pressure-sensitive adhesive composition into a sheet. Furthermore, the pressure-sensitive adhesive layer may be formed by applying a liquid pressure-sensitive adhesive containing the pressure-sensitive adhesive composition to any object. In these cases, after the pressure-sensitive adhesive layer is formed, a treatment may be performed to provide irregularities on the surface of the pressure-sensitive adhesive layer, or the pressure-sensitive adhesive layer may be formed by a method that forms irregularities on the surface.

[0077] <<Method for manufacturing electronic components or semiconductor devices using the pressure-sensitive adhesive sheet according to the present embodiment>> The pressure-sensitive adhesive sheet according to the present embodiment as described above can be used to hold an element separated from a holding substrate. For example, the pressure-sensitive adhesive sheet can be used as a die-catching sheet for catching a die such as a semiconductor die. This element is used to manufacture an electronic component or a semiconductor device. In other words, such a pressure-sensitive adhesive sheet can be used in the manufacture of an electronic component or a semiconductor device.

[0078] The method for manufacturing an electronic component or semiconductor device according to this embodiment includes the steps of separating an element from a holding substrate, deforming the convex portions of the adhesive layer to hold the element on the adhesive sheet, and restoring the convex portions to a convex shape to promote separation of the element from the adhesive sheet. The electronic component or semiconductor device may also be manufactured by further processing the element held on the adhesive sheet. Hereinafter, this method for manufacturing an electronic component or semiconductor device will be described in detail with reference to the flowchart of FIG. 4 , the schematic diagrams of FIG. 5A to FIG. 5C illustrating element separation and capture, the schematic diagrams of FIG. 6A and FIG. 6B illustrating element holding, and the schematic diagrams of FIG. 7A and FIG. 7B illustrating restoration of the convex portions.

[0079] (S10: Preparation of Holding Substrate) In step S10 shown in FIG. 4, a holding substrate to which elements are attached is prepared. The type of element is not particularly limited. The element may be, for example, a semiconductor chip such as an LED chip, a semiconductor chip with a protective film, or a semiconductor chip with a die attach film (DAF). The element may also be a micro light-emitting diode, a mini light-emitting diode, a power device, a MEMS (Micro Electro Mechanical Systems), or a controller chip, or a component thereof. The element may also be a singulated object such as a wafer, panel, or substrate. The element may have a circuit surface on which an integrated circuit having circuit elements such as transistors, resistors, and capacitors is formed. The element is not necessarily limited to a singulated object, and may also be various unsingulated wafers or substrates.

[0080] The size of the element is not particularly limited. The size of the element is preferably, for example, 100 μm. ２ More preferably, 500 μm or more ２ More preferably, 1000 μm or more ２ On the other hand, the size of the element is preferably 100 mm ２ Less than 25 mm, more preferably ２ Even more preferably, 1 mm or less ２ When small-sized elements are used, the laser lift-off method described below is suitable for separating the elements because it is easy to selectively separate small elements.

[0081] Examples of wafers include semiconductor wafers such as silicon wafers, silicon carbide (SiC) wafers, and compound semiconductor wafers (e.g., gallium phosphide (GaP) wafers, gallium arsenide (GaAs) wafers, indium phosphide (InP) wafers, and gallium nitride (GaN) wafers). The size of the wafer is not particularly limited, but is preferably 6 inches (diameter approximately 150 mm) or larger, and more preferably 12 inches (diameter approximately 300 mm) or larger. The shape of the wafer is not limited to a circle, and may be an angular shape such as a square or rectangle.

[0082] The panel may be a fan-out type semiconductor package (e.g., FOWLP or FOPLP). That is, the workpiece may be a semiconductor package before or after singulation in a fan-out type semiconductor package manufacturing technique. The size of the panel is not particularly limited, but may be, for example, a rectangular substrate of about 300 to 700 mm.

[0083] The substrate may be a glass substrate, a sapphire substrate, or a compound semiconductor substrate.

[0084] The type of the holding substrate is not particularly limited. For example, the holding substrate may be an adhesive sheet or a tray. The adhesive sheet may have an adhesive layer, and this adhesive layer may be provided on a substrate. In this case, the holding substrate can hold the element on the adhesive layer. The substrate may be a resin film or a hard substrate.

[0085] The method for preparing such a holding substrate for holding elements is not particularly limited. For example, a semiconductor wafer can be attached to the holding substrate, and the semiconductor wafer can then be diced. By dicing the semiconductor wafer in this manner, elements can be obtained, and a holding substrate with elements attached thereto can be obtained.

[0086] As another method, a semiconductor wafer can be diced, and the resulting elements can be transferred to a holding substrate to obtain a holding substrate with elements attached thereto. For example, a semiconductor wafer held on a wafer substrate can be diced, and then the resulting elements can be brought into close contact with the adhesive layer of the holding substrate. Then, an external stimulus such as laser light can be applied to reduce the adhesive strength between the wafer substrate and the elements. By this process, the elements can be transferred from the wafer substrate to the holding substrate.

[0087] As will be described later, in one embodiment, the element is separated from the holding substrate by irradiation with laser light (laser lift-off method). When using such a method, the adhesive layer of the holding substrate may contain a laser beam absorbent. Examples of the laser beam absorbent include one or more selected from pigments and dyes.

[0088] (S20: Separation of element) In step S20 shown in FIG. 4, an external stimulus is used to separate the element attached to the holding substrate from the holding substrate. Specifically, the element moves relatively away from the holding substrate. Also, the element moves relatively closer to the adhesive sheet. Then, the element comes into contact with the adhesive layer of the adhesive sheet, whereby the element is separated from the holding substrate and captured by the adhesive sheet.

[0089] 5A, by positioning a position (P1) on the adhesive sheet 150 so as to face the element 140a attached to the holding substrate 130, the element 140a to be separated is moved to the position (P1) on the adhesive sheet 150. Thereafter, as shown in FIG. 5B, an external stimulus causes the element 140a attached to the holding substrate 130 to separate from the holding substrate 130, and the element 140b is captured by the adhesive sheet 150.

[0090] 5B , by positioning a position (P2) on the adhesive sheet 150 so as to face the element 140b attached to the holding substrate 130, the element 140b to be separated is moved to the position (P2) on the adhesive sheet 150. Thereafter, in the same manner as the element 140a, the element 140 attached to the holding substrate 130 is separated from the holding substrate 130 by an external stimulus, and the element 140b is captured by the adhesive sheet 150.

[0091] In this way, the elements can be separated and captured while changing the relative positions of the holding substrate and the adhesive sheet in the planar direction, and the elements can be positioned so that the relative arrangement of the elements on the holding substrate differs from the relative arrangement of the elements on the adhesive sheet.

[0092] 5C , in another embodiment, elements 140a to 140d attached to holding substrate 130 are separated from holding substrate 130 by an external stimulus without changing the relative positions of the holding substrate and the adhesive sheet in the planar direction, and elements 140a to 140d are captured by adhesive sheet 150. In this case, the external stimulus may be applied to each element sequentially or to all elements simultaneously.

[0093] Furthermore, when an adhesive sheet with a flat surface is used, the pressure generated between the element and the adhesive sheet may cause the element 140a to be captured at a position different from the position (P1) in the example of Fig. 5A. However, by providing the adhesive layer with an uneven surface, the pressure generated between the element and the adhesive layer is alleviated, making it easier to capture the element at the desired position on the adhesive sheet.

[0094] The type of external stimulus for separating the elements is not particularly limited, and examples include application of energy, cooling, stretching of the holding substrate, and physical stimulus (e.g., pressing the rear surface of the holding substrate with a pin, etc.) By using one or more of these external stimuli, the bonding force between the holding substrate and the elements can be reduced, and the elements can be separated from the holding substrate.

[0095] Examples of energy application methods include local heating, light irradiation, and heat ray irradiation. Examples of light irradiation methods include infrared irradiation, visible light irradiation, and laser light irradiation. In one embodiment, the external stimulus is laser light irradiation, i.e., the element is separated from the holding substrate by laser lift-off. In this case, the laser light is directed toward the holding substrate at the attachment site of the specific element. For example, such laser light irradiation can be performed from the side of the holding substrate opposite the element. This generates gas at the contact site between the specific element and the holding substrate. For example, when the laser light is absorbed by the adhesive layer, at least a portion of the adhesive layer sublimes, generating gas. This sublimation of at least a portion of the adhesive layer reduces the adhesion area between the specific element and the adhesive layer, thereby reducing the adhesive strength between the specific element and the holding substrate. Furthermore, the pressure of the generated gas also reduces the adhesive strength between the specific element and the holding substrate. As a result, the specific element is separated from the holding substrate.

[0096] The conditions for irradiating the laser beam are not particularly limited. From the viewpoint of selectively and efficiently separating some elements, the frequency of the laser beam is preferably 10,000 Hz or more and 100,000 Hz or less. The beam diameter of the laser beam is preferably 10 μm or more, more preferably 20 μm or more, and is preferably 100 μm or less, more preferably 40 μm or less. The output of the laser beam is preferably 0.1 W or more and 10 W or less. The scanning speed of the laser beam is preferably 50 mm / sec or more and 2000 mm / sec or less.

[0097] (S30: Holding of Elements) In step S30, the elements separated from the holding substrate are held on an adhesive sheet. FIGS. 6A and 6B show an example of elements being held on an adhesive sheet in another embodiment in which the elements are separated and captured without changing the relative position in the planar direction between the holding substrate and the adhesive sheet shown in FIG. 5C. As shown in FIG. 5C, the plurality of elements 140a to 140d captured on the adhesive sheet 150 are covered with the holding substrate 130, and the elements 140a to 140d are pressed against the adhesive sheet 150, as shown in FIG. 6A. The member pressing the elements 140a to 140d against the adhesive sheet 150 may be any member other than the holding substrate 130, and may be, for example, a rod-shaped, needle-shaped, spherical, or plate-shaped member. The member may press all or some of the elements captured on the adhesive sheet 150. In one embodiment, a laminate sandwiching elements 140a to 140d between adhesive sheet 150 and holding substrate 130 can be passed through a laminator at a temperature of 0°C or higher and 80°C or lower and a pressure of 0.1 MPa or higher and 1 MPa or lower to press or laminate elements 140a to 140d against adhesive sheet 150.

[0098] By pressing the elements 140a to 140d against the adhesive sheet 150, as shown in FIG. 6B , multiple convex portions 111 of the adhesive layer are deformed, and the elements 140a to 140d are held by the adhesive sheet 150 (adhesive layer). Furthermore, as the convex portions 111 are deformed and crushed, the adhesive layer of the concave portions 112 swells, and the convex portions 111 and the concave portions 112 come into contact with the elements 140a to 140d. Note that in FIG. 6B , for ease of understanding, the raised portions 112a of the adhesive layer of the concave portions 112 are shown spaced apart from the convex portions 111, but the convex portions 111 and the raised portions 112a may be formed in contact with each other. This brings the elements 140a to 140d into planar contact with the adhesive layer, thereby firmly holding the elements 140a to 140d to the adhesive layer.

[0099] (S40: Processing of Elements) In step S40 shown in FIG. 4, a process for manufacturing an electronic component or a semiconductor device is performed using the elements held on the adhesive sheet. The process for manufacturing an electronic component or a semiconductor device is not particularly limited, and examples thereof include transferring the elements held on the adhesive sheet to a wiring substrate. This wiring substrate may be provided with wiring connected to the elements. In this case, the position of each element on the wiring substrate is predetermined. Therefore, in step S20, the adhesive sheet can capture the multiple elements so that the arrangement matches the relative arrangement of the multiple elements on the wiring substrate. Thereafter, a wiring substrate is bonded to the surfaces of the multiple elements opposite the adhesive sheet. Thereafter, in the next step S50, separation of the elements is promoted, and the elements are separated from the adhesive sheet.

[0100] (S50: Separation of Elements) In step S50 shown in Fig. 4, an external stimulus is used to separate the elements held on the adhesive sheet. As shown in Fig. 7A, elements 140a to 140d are held on adhesive sheet 150. By applying an external stimulus to adhesive sheet 150, multiple convex portions 111 that have been deformed or crushed are restored to their convex shape, as shown in Fig. 7B.

[0101] The type of external stimulus used to promote element separation is not particularly limited, and the external stimulus used in step S20 can be used. In one embodiment, the stretching of the adhesive sheet is used as the external stimulus to restore the deformed or crushed convex portions 111 to their convex shape. For example, in FIG. 7A , the adhesive layer is placed on a base (not shown) at a location opposite the location where the element is held, and both ends of the adhesive sheet are pressed down as indicated by arrows (P3) at a temperature of −20° C. or higher and 80° C. or lower, thereby stretching the adhesive sheet 150 and restoring the deformed or crushed convex portions 111 to their convex shape.

[0102] Furthermore, as the deformed convex portion 111 returns to its convex shape, the deformed or raised protrusion 112a returns to its concave shape, and the convex portion 111 and the elements 140a to 140d come into contact at points. In other words, the elements 140a to 140d are peeled off from the protrusion 112a. As a result, the elements 140a to 140d are weakly held by the adhesive layer.

[0103] The plurality of elements 140 a to 140 d are then separated from the adhesive sheet 150. As described above, the elements 140 a to 140 d are weakly held by the adhesive layer and are therefore easily picked up from the adhesive sheet. By using such a procedure, an electronic component or a semiconductor device having elements (e.g., semiconductor elements) can be manufactured.

[0104] The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to the following examples. Parts and percentages in each example are by weight unless otherwise specified.

[0105] The following compounds were used in the examples and comparative examples: (Component (A)) Acrylic copolymer (A1): Monomer ratio 2-ethylhexyl acrylate / 2-hydroxyethyl acrylate / acrylic acid = 92.8 / 7.0 / 0.2, weight average molecular weight (Mw) 1,100,000

[0106] (Component (B)) Energy ray curable resin (B1): Product name "Aronix M-920" manufactured by Toagosei Co., Ltd. Energy ray curable resin (B2): Tricyclodecane dimethanol diacrylate Energy ray curable resin (B3): SBS having a vinyl group on the side chain (a styrene-butadiene-styrene block copolymer having a 1,2-vinyl group on the side chain [having a branched structure and a radial structure with a branch point as a central nucleus, number average molecular weight (Mn) of 160,000, mass average molecular weight (Mw) of 180,000, styrene block content of 20 mass%, butadiene block content of 80 mass%, content of structural units having a 1,2-vinyl group on the side chain of all structural units constituting the butadiene block is 42 mol%, and melt flow rate measured under conditions of a temperature of 200°C and a load of 5 kg is 5 g / 10 min]). Energy ray curable resin (B4): PB having a vinyl group in the side chain (a polybutadiene copolymer having a 1,2-vinyl group in the side chain [mass average molecular weight (Mw) of 5,500, a glass transition temperature of -49°C, and liquid at room temperature])

[0107] (Component (C)) Crosslinking agent (C1): isocyanurate-type polyisocyanate derived from hexamethylene diisocyanate

[0108] (Component (D)) Photopolymerization initiator (D1): 1-hydroxycyclohexyl phenyl ketone Photopolymerization initiator (D2): 2,4,6-trimethylbenzoyldiphenylphosphine oxide Photopolymerization initiator (D3): bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide

[0109] (Component (E)) Antioxidant (E1): A composition in which a hindered phenol-based antioxidant and a phosphorus-based antioxidant are mixed in a mass ratio of 1:1.

[0110] Example 1 A pressure-sensitive adhesive composition was prepared by dissolving 100 parts by mass of an acrylic acid ester copolymer (A1), 5 parts by mass of an energy ray-curable resin (B1), 0.1 parts by mass of a crosslinking agent (C1), and 0.15 parts by mass of a photopolymerization initiator (D1) in toluene. This pressure-sensitive adhesive composition was applied to the release-treated surface of a release sheet (manufactured by Lintec Corporation, product name "SP-PET382150"), and the resulting coating was dried at 100°C for 2 minutes to form a 25 μm thick adhesive layer. A substrate (ethylene-methacrylic acid copolymer film, ethylene-methacrylic acid copolymer film, acid content 9% by mass, one surface of which was embossed to a matte finish, thickness 80 μm) was bonded to this adhesive layer to prepare a pressure-sensitive adhesive sheet.

[0111] After the release sheet was peeled off, the adhesive layer of the adhesive sheet was attached to a replica mold in which a concave shape had been formed in advance, and the laminate was vacuum laminated at 60° C. for 300 seconds. Next, an ultraviolet irradiator (manufactured by Heraeus) was used to irradiate the sheet with an illuminance of 130 mW / cm. ２ , light intensity 210mJ / cm ２ By irradiating the sheet with ultraviolet light at 1000 kJ / cm, a pressure-sensitive adhesive sheet having an uneven surface was produced.

[0112] The uneven shape of the adhesive layer of the adhesive sheet was a grid-like arrangement of pillars, similar to that shown in FIG. 2A. The pitch (P) between the pillars in the adhesive sheet was 20 μm. Also, as shown in FIG. 3A, the height (H) of each pillar was 8 μm, the diameter (T) of the tip was 8 μm, and the diameter (D) of the base was 16 μm. The ratio of the area of ​​the adhesive portion between the adhesive layer and the captured element (i.e., the area of ​​the tip surface of the convex portion) to the area of ​​the adhesive sheet was approximately 12.6%. The replica mold used had a surface shape complementary to the uneven shape.

[0113] (Examples 2 to 6, and Comparative Examples 1 and 2) Pressure-sensitive adhesive sheets of Examples 2 to 6 and Comparative Examples 1 and 2 were obtained in the same manner as in Example 1, except that the types and blending ratios of each component were changed to those shown in Table 1.

[0114] (Complex Shear Modulus) An adhesive layer was formed from the adhesive composition obtained in Example 1, and the adhesive layer was irradiated with an ultraviolet irradiator (manufactured by Heraeus GmbH) at an illuminance of 130 mW / cm.２ , light intensity 210mJ / cm ２ A 1 mm thick adhesive layer was prepared by irradiating the adhesive layer with ultraviolet light at 1000 W at 1000 W. The obtained adhesive layer was punched into a cylindrical shape with a diameter of 8 mm, and the complex shear modulus G* of the adhesive layer at 23°C was measured by a torsional shear method using a viscoelasticity measuring device (manufactured by Anton Paar, product name "MCR302") under the conditions of a test start temperature of -60°C, a test end temperature of 150°C, a heating rate of 3.5°C / min, and a frequency of 1 Hz. In the same manner as in Example 1, adhesive layers were prepared from the curable compositions obtained in Examples 2 to 6 and Comparative Examples 1 and 2, and the complex shear modulus G* of the adhesive layers of Examples 2 to 6 and Comparative Examples 1 and 2 was measured.

[0115] (Deformability Evaluation) The pressure-sensitive adhesive sheets obtained in the examples and comparative examples were cut to a size of 150 mm long x 50 mm wide, and laminated at room temperature (23°C) so that the adhesive layer of the pressure-sensitive adhesive sheet and the mirror surface of a wafer substrate (mirror silicone wafer, 6 inches, 150 μm thick) were adhered. The convex portions were then observed through the substrate with a microscope, and the deformability was evaluated according to the following criteria. Note that if the convex portions are deformed, the concave portions that define the boundaries of the convex portions also deform accordingly, making the convex portions undetectable. A: The number of convex portions that were not detected was 80% or more of the total convex portions. B: The number of convex portions that were not detected was 20% or more but less than 80% of the total convex portions. F: The number of convex portions that were not detected was less than 20% of the total convex portions.

[0116] (Resilience Evaluation) The adhesive layer of the adhesive sheet obtained in the example was attached to a ring frame (made of stainless steel), and the adhesive sheet was cut to fit the outer diameter of the ring frame. A wafer substrate (mirror silicon wafer, 6 inches, thickness 150 μm) was fixed to a separately prepared dicing tape and diced into 10 mm × 10 mm squares to obtain multiple elements (silicon chips, element size 10 mm × 10 mm × 150 μm). The obtained multiple elements were attached to the center of the inner ring frame of the adhesive layer of the adhesive sheet, and the dicing tape was peeled off to transfer the elements from the dicing tape to the adhesive sheet. At this time, the surface was adjusted so that the mirror surface of the silicon chip was attached to the adhesive layer of the adhesive sheet, and the attachment was performed by laminating at room temperature (23 ° C). Thereafter, the pressure-sensitive adhesive sheet on which the element was placed and supported by the ring frame was placed in an expanding device having the mechanism shown in Figures 8A and 8B, and with the element supported by a base over the pressure-sensitive adhesive sheet, the ring frame was pressed down at a speed of 1 mm / sec and a pull-down distance of 20 mm. After pressing down, the convex portions of the pressure-sensitive adhesive sheet were observed through the substrate with a microscope, and the restorability was evaluated according to the following criteria. When the convex portions have restored their original shape, the boundaries defined by the concave portions can be confirmed, and the convex portions are confirmed. A: The number of convex portions that were not confirmed was 80% or more of the total convex portions. B: The number of convex portions that were not confirmed was 20% or more but less than 80% of the total convex portions. F: The number of convex portions that were not confirmed was less than 20% of the total convex portions. The pressure-sensitive adhesive sheets of Comparative Examples 1 and 2 were rated F in the deformability evaluation, and since the convex portions were not deformed, restorability was not evaluated.

[0117] Table 1 shows the results of the complex shear modulus, deformability evaluation, and recovery evaluation for Examples 1 to 6 and Comparative Examples 1 and 2.

[0118]

[0119] The pressure-sensitive adhesive sheets of Examples 1 to 6 had a complex shear modulus of 0.001 MPa or more and 1.0 MPa or less at 23 ° C. Furthermore, the deformability of the convex portions of the pressure-sensitive adhesive sheets of Examples 1 to 4 was evaluated as A, the deformability of the convex portions of the pressure-sensitive adhesive sheets of Examples 5 and 6 was evaluated as B, and the restorability of the convex portions of the pressure-sensitive adhesive sheets of Examples 1 to 6 was evaluated as A. Thus, the pressure-sensitive adhesive sheets of Examples 1 to 6 were capable of changing the retention of elements. In other words, when the pressure-sensitive adhesive sheets of Examples 1 to 6 retain an element, their convex portions are deformed and crushed, allowing the element to be strongly retained. Furthermore, the pressure-sensitive adhesive sheets of Examples 1 to 6 retain their convex portions by external stimuli, allowing the element to be weakly retained, allowing the element to be easily picked up from the pressure-sensitive adhesive sheet.

[0120] On the other hand, the pressure-sensitive adhesive sheets of Comparative Examples 1 and 2 had a complex shear modulus of more than 1.0 MPa at 23°C. The deformability of the convex portions of the pressure-sensitive adhesive sheets of Comparative Examples 1 and 2 was evaluated as F. The pressure-sensitive adhesive sheets of Comparative Examples 1 and 2 did not deform their convex portions when holding the element, and were unable to hold the element firmly. This showed that the pressure-sensitive adhesive sheets of Comparative Examples 1 and 2 were unable to change the element holding ability.

[0121] Although the embodiments of the invention have been described above, the invention is not limited to the above-described embodiments, and various modifications and changes are possible within the scope of the gist of the invention.

[0122] This application claims priority based on Japanese Patent Application No. 2022-151756 filed on September 22, 2022, and Japanese Patent Application No. 2022-151757 filed on September 22, 2022, and Japanese Patent Application No. 2023-058459 filed on March 31, 2023, and Japanese Patent Application No. 2023-058460 filed on March 31, 2023, and Japanese Patent Application No. 2023-058462 filed on March 31, 2023, and Japanese Patent Application No. 2023-058463 filed on March 31, 2023, the entire contents of which are incorporated herein by reference.

Claims

1. An adhesive sheet comprising an adhesive layer for capturing an element separated from a substrate, wherein the adhesive layer has irregularities on its surface and has a complex shear modulus of 0.001 MPa or more and 1.0 MPa or less at 23°C. The adhesive sheet.

2. The adhesive layer has, on its surface, a plurality of convex portions that are defined by concave portions and are spaced apart from each other. When the plurality of convex portions capture the element, they are deformed by being pressed, and the deformed plurality of convex portions are restored to a convex shape by an external stimulus. The adhesive sheet according to claim 1.

3. The adhesive layer has, on its surface, a plurality of convex portions that are defined by concave portions and are spaced apart from each other. The height of the plurality of convex portions is 1 μm or more. The adhesive sheet according to claim 1.

4. The adhesive layer is formed from an adhesive composition containing an energy ray curable compound (B). The adhesive sheet according to claim 1.

5. The adhesive layer is formed from an adhesive composition containing an acrylic resin (A). The adhesive sheet according to claim 1.

6. The adhesive layer is formed from an adhesive composition containing an acrylic resin (A) and an energy ray curable compound (B). The adhesive sheet according to claim 1.

7. The adhesive layer has, on its surface, a plurality of convex portions that are defined by concave portions and are spaced apart from each other. The pitch of the plurality of convex portions is 1 μm or more and 100 μm or less. The adhesive sheet according to claim 1.

8. The adhesive layer has, on its surface, a plurality of convex portions that are defined by concave portions and are spaced apart from each other. The area of each of the plurality of convex portions is 10 μm ２ or more and 2000 μm ２ or less. The pressure-sensitive adhesive sheet according to claim 1.

9. The adhesive layer has, on its surface, a plurality of convex portions that are defined by concave portions and are spaced apart from each other. The ratio of the area occupied by the convex portions to the area of the adhesive layer is 1% or more and 95% or less. The adhesive sheet according to claim 1.

10. The adhesive layer is configured such that the ratio of the adhesion area between the adhesive layer and one element to the area of one element is 1% or more and 95% or less. The adhesive sheet according to claim 1.

11. The adhesive layer has, on its surface, a plurality of convex portions that are defined by concave portions and are spaced apart from each other. When the plurality of convex portions capture the element, they are deformed so that the concave portions come into contact with the element by being pressed. The adhesive sheet according to claim 1.

12. The plurality of deformed convex portions are restored to a convex shape by an external stimulus so that the concave portions in contact with the element are separated from the element. The adhesive sheet according to claim 11.

13. A step of separating an element adhered to a holding substrate from the holding substrate by an external stimulus; Pressing the element separated from the holding substrate against the adhesive sheet according to claim 1 to deform a plurality of convex portions defined by boundaries by concave portions and spaced apart from each other on the surface of the adhesive layer, bringing the concave portions into contact with the element, and holding the element on the adhesive layer; A step of restoring the plurality of deformed convex portions to a convex shape by an external stimulus, separating the concave portions in contact with the element from the element, and promoting separation of the element from the adhesive sheet; A method for manufacturing an electronic component or a semiconductor device, comprising: