Protective film-forming film and method for manufacturing workpiece with protective film

Abstract

Provided is a protective film-forming film for forming a protective film in a workpiece with a protective film including a workpiece and the protective film provided at any position thereof, in which the protective film-forming film is capable of performing printing in a sufficiently dark color on the protective film even in the case of the protective film having a high light reflectance for making the workpiece with a protective film inconspicuous on a white substrate.SOLUTION: The reflectivity of the cured product of the curable protection membrane-forming film 13 with respect to light in the entire range of wavelengths from 420 to 700nm is set to 22% or greater, and the absorbance of the cured product with respect to light of either one or both of the wavelengths 532nm and 1064nm is set to 7% or greater, or the reflectivity of the non-curable protection membrane-forming film 13 with respect to light in the entire range of wavelengths from 420 to 700nm is set to 22% or greater, and the absorbance of the protection membrane-forming film 13 with respect to light of either one or both of the wavelengths 532nm and 1064nm is set to 7% or greater.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a protective film-forming film and a method for manufacturing a workpiece with a protective film. [Background technology]

[0002] Some wafers, such as semiconductor wafers and insulator wafers, have circuits formed on one surface (circuit surface) and also have protruding electrodes such as bumps on that surface (circuit surface). Such wafers are divided into chips, and the protruding electrodes are connected to connection pads on a circuit board, thereby mounting the chips on the circuit board. In such wafers and chips, the surface opposite to the circuit surface (back surface) may be protected with a protective film in order to prevent damage such as cracks from occurring. Furthermore, in the manufacturing process of a semiconductor device, a semiconductor device panel, which will be described later, is used as a workpiece, and in order to prevent warping or cracks from occurring in this panel, some part of the panel may be protected with a protective film.

[0003] In such a case, for example, a protective film-forming film for forming a protective film is attached to a desired location on the workpiece, such as the back surface of a wafer, and then the workpiece is processed to produce a workpiece, and the protective film-forming film is cured as necessary, and the protective film-forming film or the protective film is cut to produce a workpiece with a protective film, which includes the workpiece and a protective film provided at any location on the workpiece. An example of a workpiece with a protective film is a semiconductor chip with a protective film, which includes a semiconductor chip and a protective film provided on its back surface.

[0004] White substrates are sometimes used as circuit boards for light-emitting devices. In such cases, it is preferable to use a protective film with high light reflectance so that the workpiece with the protective film is less noticeable on the white substrate. As protective film-forming films capable of forming such protective films, there have been disclosed protective film-forming films that are curable and have a reflectance of 20% or more for light in the entire wavelength range of 400 to 700 nm, and non-curable protective film-forming films that have a reflectance of 20% or more for light in the entire wavelength range of 400 to 700 nm (see Patent Document 1). This non-curable protective film-forming film itself functions as a protective film. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2023-043538 Summary of the Invention [Problem to be solved by the invention]

[0006] Typically, the protective film in a protective film-coated workpiece is printed to identify it. When the protective film-forming film is curable, printing can be performed on the cured product of the protective film-forming film (i.e., the protective film), or on the protective film-forming film before curing. Printing is typically performed by irradiating the film with a laser having a wavelength of 532 nm or 1064 nm. However, in protective film-forming films or protective films with high light reflectivity, absorption of light with a wavelength of 532 nm or 1064 nm is suppressed. Therefore, it has been difficult to print characters with a color dark enough to be clearly visible, especially in the case of small characters. In contrast, the protective film-forming film disclosed in Patent Document 1 does not address this issue, and it is unclear whether it can solve this problem.

[0007] The present invention aims to provide a protective film-forming film for forming a protective film in a protective film-equipped workpiece comprising a workpiece and a protective film provided at any location on the workpiece, and which is capable of applying printing in a sufficiently dark color to the protective film even if the protective film has a high light reflectance to make the protective film-equipped workpiece less noticeable on a white substrate. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention employs the following configuration. [1] A protective film-forming film for forming a protective film at any location on a workpiece obtained by processing a workpiece, wherein, when the protective film-forming film is curable, the cured product of the protective film-forming film has a reflectance of 22% or more for light in the entire wavelength range of 420 to 700 nm, and an absorptance of 7% or more for light at either or both of wavelengths of 532 nm and 1064 nm for the cured product; and when the protective film-forming film is non-curable, the protective film-forming film has a reflectance of 22% or more for light in the entire wavelength range of 420 to 700 nm, and an absorptance of 7% or more for light at either or both of wavelengths of 532 nm and 1064 nm for the protective film-forming film. [2] The protective film-forming film according to [1], wherein, when the protective film-forming film is curable, the cured product of the protective film-forming film has a transmittance of 40% or less for light in the entire wavelength range of 420 to 700 nm, and when the protective film-forming film is non-curable, the protective film-forming film has a transmittance of 40% or less for light in the entire wavelength range of 420 to 700 nm. [3] The protective film-forming film according to [1] or [2], wherein the protective film-forming film contains a white pigment.

[0009] [4] A protective film-forming film according to any one of [1] to [3], wherein, when the protective film-forming film is curable, the difference between the maximum and minimum values ​​of reflectance of the cured product of the protective film-forming film in the wavelength range of 420 to 700 nm is 20% or less, and when the protective film-forming film is non-curable, the difference between the maximum and minimum values ​​of reflectance of the protective film-forming film in the wavelength range of 420 to 700 nm is 20% or less. [5] A protective film-forming film described in any one of [1] to [4], wherein the protective film-forming film contains a carbon material, and the content ratio of the carbon material in the protective film-forming film relative to the total mass of the protective film-forming film is 0.1 mass% or less. [6] A method for manufacturing a workpiece with a protective film using a protective film-forming film described in any one of [1] to [5], wherein if the protective film-forming film is curable, the cured product of the protective film-forming film is the protective film, and if the protective film-forming film is non-curable, the protective film-forming film after being attached to the workpiece is the protective film, and in the manufacturing method, the protective film-forming film is attached to the workpiece, printing is performed on the protective film-forming film or protective film after being attached to the workpiece, and the workpiece after being attached with the protective film-forming film is processed to produce the workpiece, and the protective film-forming film or protective film after being attached to the workpiece is cut, and if the protective film-forming film is curable, the protective film is further formed by curing the protective film-forming film after being attached to the workpiece. [Effects of the Invention]

[0010] According to the present invention, there is provided a protective film forming film for forming a protective film in a protective film-equipped workpiece comprising a workpiece and a protective film provided at any location on the workpiece, and which is capable of applying printing in a sufficiently dark color to the protective film even if the protective film has a high light reflectivity to make the protective film-equipped workpiece less noticeable on a white substrate. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a cross-sectional view schematically illustrating an example of a protective film-forming film according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] ◇Protective film forming film A protective film-forming film according to one embodiment of the present invention is a protective film-forming film for forming a protective film at any location on a workpiece obtained by processing a workpiece, and when the protective film-forming film is curable, the cured product of the protective film-forming film has a reflectance of 22% or more for light in the entire wavelength range of 420 to 700 nm, and an absorptance of 7% or more for light at either or both of wavelengths of 532 nm and 1064 nm for the cured product; when the protective film-forming film is non-curable, the protective film-forming film has a reflectance of 22% or more for light in the entire wavelength range of 420 to 700 nm, and an absorptance of 7% or more for light at either or both of wavelengths of 532 nm and 1064 nm for the protective film-forming film. The protective film-forming film of this embodiment can be laminated with a support sheet to form a composite sheet for forming a protective film, as will be described later, for example.

[0013] The protective film-forming film of this embodiment is attached to any location on the workpiece, and ultimately forms a protective film, thereby making it possible to protect the processed workpiece. The protective film-forming film of this embodiment is soft and can be attached to a workpiece before it is processed into a workpiece. That is, by using the protective film-forming film of this embodiment or a composite sheet for forming a protective film including the same, it is possible to manufacture a workpiece with a protective film, which includes a workpiece and a protective film provided at any location on the workpiece. Then, prior to manufacturing the workpiece with a protective film, it is possible to manufacture a workpiece with a protective film-forming film, which includes a workpiece and the protective film-forming film provided at any location on the workpiece, by using the protective film-forming film.

[0014] In this embodiment, the workpiece is obtained by machining a workpiece. Examples of the workpiece include a wafer and a semiconductor device panel.

[0015] Examples of the wafer include semiconductor wafers made of elemental semiconductors such as silicon, germanium, and selenium, and compound semiconductors such as GaAs, GaP, InP, CdTe, ZnSe, and SiC; and insulating wafers made of insulators such as sapphire and glass. For example, if the workpiece is a semiconductor wafer, the workpiece artifact may be a semiconductor chip. One surface of these wafers is a circuit surface on which circuits are formed, and the opposite surface is referred to as the "back surface" in this specification. The same applies to chips produced by dividing a wafer by means of dicing or the like, and the surface opposite to the circuit surface on which the circuits of the chip are formed is called the "back surface." Both the circuit surface of the wafer and the circuit surface of the chip are provided with protruding electrodes such as bumps and pillars.

[0016] The semiconductor device panel is handled during the manufacturing process of a semiconductor device, and a specific example thereof is a panel that uses a semiconductor device in which one or more electronic components are sealed with sealing resin, and is configured by arranging multiple such semiconductor devices in a plane within an area of ​​a circular, rectangular, or other shape.

[0017] The workpiece is preferably a chip (e.g., a semiconductor chip) mounted on a substrate device, and may be a chip in a light-emitting device, such as a wafer-level chip-scale package (WLCSP) for current control. The light-emitting device may be any device equipped with a light-emitting element such as an LED (Light Emitting Diode), and its type is not particularly limited. Examples of the light-emitting device include a substrate device having a surface-mounted LED package equipped with a light-emitting element, a substrate device equipped with a mini LED element, and a substrate device equipped with a micro LED element.

[0018] In this specification, the term "substrate device" refers to a workpiece with a protective film, which is flip-chip connected to connection pads on a circuit board via protruding electrodes on its circuit surface. For example, if a semiconductor wafer is used as the workpiece, the substrate device may be a semiconductor device equipped with a semiconductor chip with a protective film.

[0019] Circuit boards in light-emitting devices often have a high visible light reflectance and are white in color. For example, a typical white circuit board has a light reflectance of 30% or more over the entire wavelength range of 420 to 700 nm. In contrast, the protective film obtained using the protective film-forming film of this embodiment has a high reflectance of visible light, and the protective film is preferably white. Therefore, as will be described later, a workpiece having such a protective film does not stand out on a white substrate (circuit board) in a light-emitting device, and the design of the device having the workpiece having the protective film is high.

[0020] The protective film-forming film of the present embodiment may be curable or non-curable. That is, the protective film-forming film may function as a protective film by being cured, or may function as a protective film in an uncured state. The curable protective film-forming film may be either thermosetting or energy ray-curable, or may have both thermosetting and energy ray-curable properties.

[0021] In this specification, the term "energy ray" refers to an electromagnetic wave or a charged particle beam that has an energy quantum. Examples of energy rays include ultraviolet rays, radioactive rays, and electron beams. In this specification, "energy ray curable" means a property of being cured by irradiation with energy rays, and "non-energy ray curable" means a property of not being cured even when irradiated with energy rays. In this specification, "non-curable" means a property that does not cure by any means such as heating, irradiation with energy rays, etc. A non-curable protective film-forming film can be considered to be a protective film after it is provided (formed) on a target object.

[0022] <<Reflectance of light (420~700nm)>> When the protective film-forming film of the present embodiment is curable, the cured product of the protective film-forming film has a reflectance of 22% or more for light in the entire wavelength range of 420 to 700 nm. In other words, the minimum reflectance of the cured product of the protective film-forming film for light in the wavelength range of 420 to 700 nm is 22% or more. When the protective film-forming film of this embodiment is non-curable, the reflectance of the protective film-forming film for light in the entire wavelength range of 420 to 700 nm is 22% or more, in other words, the minimum reflectance of the protective film-forming film for light in the wavelength range of 420 to 700 nm is 22% or more. In this specification, "light in the entire wavelength range of 420 to 700 nm" may be referred to as "light (420 to 700 nm)."

[0023] In a protective film obtained using a protective film-forming film having the above-mentioned light (420 to 700 nm) reflectance characteristics, visible light absorption is suppressed more than usual, and the protective film is preferably white. Therefore, a protective film-equipped workpiece having such a protective film does not stand out on a white substrate in a light-emitting device, and the design of the device including the protective film-equipped workpiece is high. Furthermore, even if a protective film has a high light reflectance to make the protective film-equipped workpiece less noticeable on a white substrate, if the protective film is obtained using a protective film-forming film having the above-mentioned light absorptance characteristics, it can be printed in a sufficiently dark color.

[0024] That is, in this embodiment, the workpiece is preferably a chip in a light-emitting device, and may be a semiconductor chip in a light-emitting device.

[0025] In this specification, unless otherwise specified, "applying printing to a protective film" means that printing is performed on a curable or non-curable protective film-forming film, and if the protective film-forming film is curable, the protective film-forming film after printing is further cured or printing is performed on the protective film to obtain a protective film with printing formed on it.

[0026] In this specification, unless otherwise specified, the cured product of the protective film-forming film means a cured product with a sufficiently high degree of curing, and is synonymous with the protective film.

[0027] In this specification, unless otherwise specified, "reflectance of light (420 to 700 nm)" means "reflectance of light (420 to 700 nm) of the cured product of the protective film-forming film" when the protective film-forming film is curable, and means "reflectance of light (420 to 700 nm) of the protective film-forming film" when the protective film-forming film is non-curable.

[0028] As described later in the Examples, the reflectance of light (420 to 700 nm) can be measured by measuring the amount of total reflected light for each of the protective film-forming film or its cured product and a barium sulfate reference plate, and determining the ratio of the measured value for the protective film-forming film or its cured product to the measured value for the reference plate (i.e., relative total light reflectance).The maximum and minimum values ​​among these can be used as the maximum and minimum values ​​of the reflectance of light (420 to 700 nm) described later, respectively.

[0029] The reflectance of light (420 to 700 nm) may be 22% or more, for example, more than 40%, more than 50%, more than 55%, more than 60%, or more than 70%. The higher the reflectance of light (420 to 700 nm), the less noticeable the workpiece with the protective film becomes on the white substrate in the light-emitting device. The upper limit of the reflectance of light (420 to 700 nm) is not particularly limited. For example, a protective film-forming film having a reflectance of light (420 to 700 nm) of 95% or less can be more easily realized. In other words, the maximum reflectance of light (420 to 700 nm) may be 95% or less.

[0030] It is preferable that the reflectance of the curable protective film-forming film in an uncured state (i.e., of the protective film-forming film itself) for light in the entire wavelength range of 420 to 700 nm is in the same range as the reflectance of the light (420 to 700 nm) of the cured product of the above-mentioned protective film-forming film (e.g., 22% or more).

[0031] In the protective film-forming film and its cured product, the reflectance of light (420 to 700 nm) can be adjusted, for example, by adjusting the type and content of the components contained in the protective film-forming film. In particular, the protective film-forming film contains a colorant (colorant (J) in a thermosetting protective film-forming film, and a colorant in an energy ray-curable protective film-forming film and a non-curable protective film-forming film) described below, and the reflectance of the protective film-forming film and its cured product at light (420 to 700 nm) can be adjusted by adjusting the type and content of the colorant in the protective film-forming film. When the colorant is a pigment, the reflectance of the protective film-forming film and its cured product at light (420 to 700 nm) can also be adjusted by its particle size. For example, by using a colorant with high whiteness in the protective film and increasing its content, the reflectance of the protective film-forming film and its cured product at light (420 to 700 nm) can be increased. For example, when the protective film-forming film contains a white pigment, the reflectance of the protective film-forming film and its cured product to light (420 to 700 nm) can be more easily increased. That is, the protective film-forming film of the present embodiment preferably contains a white pigment. The white pigment will be described in detail later.

[0032] When the protective film-forming film contains a white pigment, the content of the white pigment in the protective film-forming film relative to the total mass of the protective film-forming film is preferably 0.8% by mass or more, and may be, for example, any one of 3% by mass or more, 7% by mass or more, 15% by mass or more, 25% by mass or more, and 35% by mass or more. When the content is in such a range, the reflectance of the protective film-forming film and its cured product to light (420 to 700 nm) can be further increased. On the other hand, in terms of improving the film-forming properties, flexibility, toughness, spreadability, etc. of the protective film-forming film, the ratio is preferably 60% by mass or less. The content ratio of the white pigment shown here applies to the thermosetting protective film-forming film, the energy ray-curable protective film-forming film, and the non-curable protective film-forming film, which will be described later. The content of the white pigment in the protective film-forming film may be adjusted appropriately depending on the type of the protective film-forming film.

[0033] In the protective film obtained using the protective film-forming film having the reflectance characteristics of light (420 to 700 nm) as described above, the absorption of visible light is suppressed more than usual, and the protective film is preferably white. Therefore, a workpiece having such a protective film does not stand out on a white substrate in a light-emitting device, and the design of the device having the workpiece having the protective film is high.

[0034] <<The difference between the maximum and minimum reflectance values ​​of light (420-700nm)>> When the protective film-forming film of the present embodiment is curable, the difference between the maximum and minimum values ​​of the reflectance of light (420 to 700 nm) of the cured product of the protective film-forming film is preferably 20% or less. When the protective film-forming film of the present embodiment is non-curable, the difference between the maximum and minimum values ​​of the reflectance of the protective film-forming film for light (420 to 700 nm) is preferably 20% or less. The smaller the difference, the more likely it is that the reflectance is neither high nor low in only a specific narrow wavelength range, which means that it is less likely to appear bluish-white, reddish-white, etc., and therefore the protective film has a better ability to make the workpiece with the protective film less noticeable on a white substrate.

[0035] In order to enhance the above-mentioned effect, regardless of whether the protective film-forming film is curable or not, it is more preferable that the difference between the maximum and minimum values ​​of the reflectance of light (420 to 700 nm) is 16% or less, and may be, for example, any of 12% or less, 10% or less, and 6% or less. The lower limit of the difference is not particularly limited. For example, a protective film-forming film having a difference of 2% or more can be more easily realized. In one embodiment, the difference may be, for example, any one of 2 to 20%, 2 to 16%, 2 to 12%, 2 to 10%, and 2 to 6%, although these are just examples of the difference.

[0036] It is preferable that the difference between the maximum and minimum values ​​of the reflectance of light in the wavelength range of 420 to 700 nm of the curable protective film-forming film in an uncured state (i.e., of the protective film-forming film itself) is in the same range as the difference between the maximum and minimum values ​​of the reflectance of light (420 to 700 nm) of the cured product of the above-mentioned protective film-forming film (e.g., 20% or less).

[0037] <<Light (532nm) absorption rate>> When the protective film-forming film of this embodiment is curable, the absorptivity of the cured product of the protective film-forming film at a wavelength of 532 nm is 7% or more when the absorptivity of the cured product at a wavelength of 1064 nm is less than 7%. When the protective film-forming film of this embodiment is non-curable, the absorptivity of the protective film-forming film for light with a wavelength of 532 nm is 7% or more when the absorptivity of the protective film-forming film for light with a wavelength of 1064 nm is less than 7%. In this specification, "light with a wavelength of 532 nm" may be referred to as "light (532 nm)," and "light with a wavelength of 1064 nm" may be referred to as "light (1064 nm)."

[0038] Regardless of whether the protective film-forming film is curable or not, a protective film-forming film having the above-mentioned light (532 nm) absorptivity characteristics, or a protective film (cured product) obtained using the same, has a high light reflectance of the protective film, but when laser printing is performed on the protective film-forming film or its cured product by irradiating it with a laser having a wavelength of 532 nm (sometimes referred to as a "laser (532 nm)" in this specification), unlike conventional methods, the laser (532 nm) is absorbed moderately by the protective film-forming film or its cured product, and even fine printing can be printed in a dark color that is sufficiently visible.

[0039] In this specification, unless otherwise specified, "absorbance of light (532 nm)" means "absorbance of light (532 nm) of the cured product of the protective film-forming film" when the protective film-forming film is curable, and means "absorbance of light (532 nm) of the protective film-forming film" when the protective film-forming film is non-curable. This also applies to "absorbance of light (1064 nm)." In this specification, the "laser with a wavelength of 1064 nm" described below may be referred to as the "laser (1064 nm)", just as in the case of the "laser with a wavelength of 532 nm".

[0040] When the absorptance of light (1064 nm) is less than 7%, the absorptance of light (532 nm) may be, for example, any of 7.8% or more, 8.5% or more, 9.2% or more, and 10% or more, in order to enhance the above-mentioned effect.

[0041] When the protective film-forming film of this embodiment is curable, the absorptivity of the cured product of the protective film-forming film for light (532 nm) is not particularly limited as long as the absorptivity of the cured product for light (1064 nm) is 7% or more. When the protective film-forming film of this embodiment is non-curable, the absorptivity of the protective film-forming film for light (532 nm) is not particularly limited, provided that the absorptivity of the protective film-forming film for light (1064 nm) is 7% or more.

[0042] When the absorptance of light (1064 nm) is 7% or more, the absorptance of light (532 nm) may be, for example, any one of 2% or more, 10% or more, 18% or more, and 26% or more, or, similar to the case where the absorptance of light (1064 nm) is less than 7%, the absorptance may be any one of 7% or more, 7.8% or more, 8.5% or more, 9.2% or more, and 10% or more.

[0043] In particular, when the absorptance of light (532 nm) and the absorptance of light (1064 nm) are both 7% or more, whether a laser (532 nm) or a laser (1064 nm) is used to laser print on the protective film-forming film or its cured product, even fine printing can be printed in a dark color that is sufficiently visible.

[0044] Regardless of whether the absorptance of light (1064 nm) is 7% or more, the absorptance of light (532 nm) is preferably 34% or less. Such a protective film-forming film can be more easily realized.

[0045] It is preferable that the absorptivity of light with a wavelength of 532 nm of the curable protective film-forming film in an uncured state (i.e., of the protective film-forming film itself) is in the same range as the absorptivity of light (532 nm) of the cured product of the above-mentioned protective film-forming film (e.g., 7% or more or 2% or more).

[0046] The light (532 nm) absorptance of the protective film-forming film or its cured product can be calculated using the measured light (532 nm) reflectance and light (532 nm) transmittance of the protective film-forming film or its cured product obtained by measuring using a known method. For example, the light (532 nm) absorptance of the cured product of the protective film-forming film can be calculated according to the following formula (i). [Absorption rate (%) of light (532 nm) of the cured product of the protective film-forming film] = 100 - ([Reflectance (%) of light (532 nm) of the cured product of the protective film-forming film] + [Transmittance (%) of light (532 nm) of the cured product of the protective film-forming film]) (i) The absorptance of the protective film-forming film for light (532 nm) can be calculated in the above formula (i) regardless of whether the protective film-forming film is curable or not, by substituting the measured value of the reflectance of the protective film-forming film for light (532 nm) of the cured product, and by substituting the measured value of the transmittance of the protective film-forming film for light (532 nm) of the cured product.

[0047] <<Light (1064nm) absorption rate>> When the protective film-forming film of this embodiment is curable, the absorptance of the cured product of the protective film-forming film at a wavelength of 1064 nm is 7% or more when the absorptance of the cured product at a wavelength of 532 nm is less than 7%. When the protective film-forming film of this embodiment is non-curable, the absorptivity of the protective film-forming film for light with a wavelength of 1064 nm is 7% or more when the absorptivity of the protective film-forming film for light with a wavelength of 532 nm is less than 7%.

[0048] Regardless of whether the protective film-forming film is curable or not, a protective film-forming film having the above-mentioned light (1064 nm) absorptivity characteristics, or a protective film (cured product) obtained using the same, is suitable for printing by irradiation with a laser (1064 nm) while having a high light reflectance of the protective film. That is, such a protective film-forming film or its cured product moderately absorbs the laser (1064 nm), and even fine printing can be printed in a dark color that is sufficiently visible.

[0049] When the absorptance of light (532 nm) is less than 7%, the absorptance of light (1064 nm) may be, for example, any of 7.5% or more, 8% or more, 8.5% or more, and 9% or more, in order to enhance the above-mentioned effect.

[0050] When the protective film-forming film of this embodiment is curable, the absorptivity of the cured product of the protective film-forming film for light (1064 nm) is not particularly limited, provided that the absorptivity of the cured product for light (532 nm) is 7% or more. When the protective film-forming film of this embodiment is non-curable, the absorptivity of the protective film-forming film for light (1064 nm) is not particularly limited, provided that the absorptivity of the protective film-forming film for light (532 nm) is 7% or more.

[0051] When the absorptance of light (532 nm) is 7% or more, the absorptance of light (1064 nm) may be, for example, any one of 2% or more, 10% or more, 18% or more, and 26% or more, or, similar to the above-mentioned case where the absorptance of light (532 nm) is less than 7%, it may be, for example, any one of 7% or more, 7.5% or more, 8% or more, 8.5% or more, and 9% or more.

[0052] Regardless of whether the absorptance of light (532 nm) is 7% or more, the absorptance of light (1064 nm) is preferably 30% or less. Such a protective film-forming film can be more easily realized.

[0053] It is preferable that the absorptivity of light with a wavelength of 1064 nm of the curable protective film-forming film in an uncured state (i.e., of the protective film-forming film itself) is in the same range as the absorptivity of light (1064 nm) of the cured product of the above-mentioned protective film-forming film (e.g., 7% or more or 2% or more).

[0054] The light (1064 nm) absorptance of the protective film-forming film or its cured product can be calculated in the same manner as the light (532 nm) absorptance of the protective film-forming film or its cured product described above, except that the measurement wavelength is 1064 nm instead of 532 nm.

[0055] In the protective film-forming film and its cured product, the absorptance of light (532 nm) and the absorptance of light (1064 nm) can be adjusted, for example, by adjusting the type and content of the components contained in the protective film-forming film. In particular, the protective film-forming film contains a component that is a light absorber among the colorants described below (colorant (J) in a thermosetting protective film-forming film, colorants in an energy ray-curable protective film-forming film and a non-curable protective film-forming film), and by adjusting the type and content of the light absorber in the protective film-forming film, the absorptance of light (532 nm) and the absorptance of light (1064 nm) of the protective film-forming film and its cured product can be adjusted. For example, by increasing the content of the light absorber in the protective film-forming film, the absorptance of light (532 nm) and the absorptance of light (1064 nm) can be increased. That is, the protective film-forming film of the present embodiment preferably contains a light absorbing agent. The light absorbing agent will be described in detail later.

[0056] When the protective film-forming film contains a light absorber, the content ratio of the light absorber in the protective film-forming film relative to the total mass of the protective film-forming film is preferably 0.005% by mass or more, more preferably 0.01% by mass or more, and may be, for example, either 0.1% by mass or more or 0.3% by mass or more. When the ratio is equal to or more than the lower limit, the absorptance of the protective film-forming film and its cured product at light (532 nm) and light (1064 nm) can be further increased. On the other hand, the ratio is preferably 0.7% by mass or less, and may be, for example, 0.1% by mass or less. When the ratio is equal to or less than the upper limit, the reflectance of the protective film-forming film and its cured product to light (420 to 700 nm) can be further increased. The content ratio of the light absorber shown here applies to the thermosetting protective film-forming film, the energy ray-curable protective film-forming film, and the non-curable protective film-forming film, which will be described later.

[0057] When the protective film-forming film contains a carbon material as a light absorber, the content ratio of the carbon material in the protective film-forming film to the total mass of the protective film-forming film is preferably 0.005 mass% or more, and may be, for example, 0.008 mass% or more. When the ratio is equal to or more than the lower limit, the absorptance of the protective film-forming film and its cured product at light (532 nm) and light (1064 nm) can be further increased. On the other hand, the ratio is preferably 0.1% by mass or less, and may be, for example, any one of 0.05% by mass or less, 0.04% by mass or less, and 0.03% by mass or less. When the ratio is equal to or less than the upper limit, the reflectance of the protective film-forming film and its cured product to light (420 to 700 nm) can be further increased. A trace amount of carbon material can maintain a high reflectance of light (420 to 700 nm) while also increasing the absorptance of light (532 nm) and light (1064 nm), and is particularly advantageous in that by setting the proportion to 0.1 mass% or less, the desired optical properties of the protective film can be easily achieved. That is, an example of a preferred protective film-forming film of this embodiment is a protective film-forming film that contains a carbon material and in which the proportion of the carbon material content relative to the total mass of the protective film is 0.1 mass% or less. The content ratio of the carbon material shown here applies to the thermosetting protective film-forming film, the energy ray-curable protective film-forming film, and the non-curable protective film-forming film, which will be described later.

[0058] <<Light (420~700nm) transmittance>> When the protective film-forming film of the present embodiment is curable, the transmittance of the cured product of the protective film-forming film to light in the entire wavelength range of 420 to 700 nm (i.e., light (420 to 700 nm)) is preferably 40% or less. In other words, the maximum value of the transmittance of the cured product of the protective film-forming film to light (420 to 700 nm) is preferably 40% or less. When the protective film-forming film of the present embodiment is non-curable, the transmittance of the protective film-forming film to light in the entire wavelength range of 420 to 700 nm (i.e., light (420 to 700 nm)) is preferably 40% or less. In other words, the maximum value of the transmittance of the protective film-forming film to light (420 to 700 nm) is preferably 40% or less. The lower the transmittance, the less influence the components (usually the workpiece) that are in contact with the protective film in the workpiece with a protective film have on the color of the protective film when the workpiece with a protective film is viewed from the protective film side, and the more the protective film can be seen in a color that is closer to its inherent color.

[0059] In this specification, unless otherwise specified, "transmittance of light (420 to 700 nm)" means "transmittance of light (420 to 700 nm) of the cured product of the protective film-forming film" when the protective film-forming film is curable, and means "transmittance of light (420 to 700 nm) of the protective film-forming film" when the protective film-forming film is non-curable.

[0060] In order to further enhance the above-mentioned effects, the transmittance of light (420 to 700 nm) may be, for example, any one of 34% or less, 29% or less, 24% or less, and 19% or less, regardless of whether the protective film-forming film is curable or not. The lower limit of the transmittance of light (420 to 700 nm) is not particularly limited. For example, a protective film-forming film having a transmittance of light (420 to 700 nm) of 2% or more can be more easily realized. In one embodiment, the transmittance of light (420 to 700 nm) may be, for example, any one of 2 to 40%, 2 to 34%, 2 to 29%, 2 to 24%, and 2 to 19%, although these are just examples of the transmittance of light (420 to 700 nm).

[0061] It is preferable that the transmittance of light in the entire wavelength range of 420 to 700 nm of the curable protective film-forming film in an uncured state (i.e., of the protective film-forming film itself) is in the same range as the transmittance of light (420 to 700 nm) of the cured product of the above-mentioned protective film-forming film (e.g., 40% or less).

[0062] In the protective film-forming film and its cured product, the transmittance of light (420 to 700 nm) can be adjusted, for example, by adjusting the type and content of the components contained in the protective film-forming film. In particular, if the protective film-forming film contains a colorant (colorant (J) in the thermosetting protective film-forming film, and the colorant in the energy ray-curable protective film-forming film and the non-curable protective film-forming film) described below, and the type and content of the colorant in the protective film-forming film are adjusted, the transmittance of light (420 to 700 nm) of the protective film-forming film and its cured product can be more easily adjusted.

[0063] <<Color tone on both sides of protective film>> It is preferable that the color tone of at least both sides of the protective film-forming film of this embodiment is uniform, and the color tone of the entire protective film-forming film may be uniform. Such a protective film-forming film is advantageous in that the printing can be clearly confirmed visually in the final state of the protective film to which printing has been applied. Furthermore, such a protective film-forming film is advantageous in that it is easy to manufacture and that the color tone of all protective film-coated workpieces produced from a single protective film-coated workpiece is uniform. Both surfaces of the protective film-forming film are, for example, the same as the first and second surfaces described below.

[0064] In this specification, the phrase "both surfaces of the protective film-forming film have a single color tone" means that both surfaces of the protective film-forming film have a single color tone (the same color) throughout their entire area. In this specification, the term "the first and second sides of the protective film-forming film have a single color tone" means that when the light reflectance of the first side of the protective film-forming film is measured at wavelengths of 1 nm each over the entire wavelength range of 420 to 700 nm, the light reflectance at a wavelength of x nm (x is any integer between 420 and 700) is defined as light reflectance R1(x), and the light reflectance of the second side of the protective film measured in the same manner is defined as light reflectance R2(x), and the difference in light reflectance for each wavelength is calculated using the formula: R1(x)-R2(x), the maximum absolute value of all the differences in light reflectance is less than 1.5%. In this specification, the phrase "the entire color tone of the protective film-forming film is uniform" means that not only the entire area on both sides of the protective film-forming film, but also the entire interior area has a single color tone (the color is the same).

[0065] The color tone of the protective film-forming film can be adjusted, for example, by adjusting the type and content of the components contained in the protective film-forming film. In particular, the color tone of the protective film-forming film can be more easily adjusted by adjusting the type and content of the colorant contained in the protective film-forming film.

[0066] When the protective film-forming film is thermosetting, the cured product of the protective film-forming film that defines the reflectance of light (420 to 700 nm), the absorbance of light (532 nm), the absorbance of light (1064 nm), and the transmittance of light (420 to 700 nm) is a thermosetting product, and the protective film is a cured product obtained by heating the protective film-forming film at 140°C for 2 hours. When the protective film-forming film is energy ray curable, the cured product of the protective film-forming film that specifies the reflectance of light (420 to 700 nm), the absorbance of light (532 nm), the absorbance of light (1064 nm), and the transmittance of light (420 to 700 nm) is an energy ray cured product, and the protective film is a protective film that has an illuminance of 220 mW / cm with respect to the protective film-forming film. 2 , energy ray dose 600mJ / cm 2 The cured product is obtained by irradiating the resin with energy rays under the conditions described above.

[0067] The protective film-forming film may be composed of one layer (single layer) or two or more layers. When the protective film-forming film is composed of multiple layers, these multiple layers may be the same or different from each other, and the combination of these multiple layers is not particularly limited.

[0068] In this specification, not only in the case of a protective film-forming film, "multiple layers may be the same or different from each other" means "all layers may be the same, all layers may be different, or only some layers may be the same," and further, "multiple layers are different from each other" means "at least one of the constituent materials and thicknesses of each layer is different from each other."

[0069] The thickness of the protective film-forming film is preferably less than 50 μm, more preferably 45 μm or less. By making the thickness of the protective film-forming film equal to or less than the upper limit, the thickness of the protective film-coated workpiece can be reduced, and various devices such as light-emitting devices equipped with the protective film-coated workpiece can be made thinner. The lower limit of the thickness of the protective film-forming film is not particularly limited. For example, the thickness of the protective film-forming film is preferably 10 μm or more in order to enhance the protective effect of the protective film. Here, the "thickness of the protective film-forming film" means the thickness of the entire protective film-forming film, and for example, the thickness of a protective film-forming film consisting of multiple layers means the total thickness of all layers constituting the protective film-forming film. This also applies to other layers such as the substrate and pressure-sensitive adhesive layer described below.

[0070] In this specification, not only in the case of protective film-forming films, but unless otherwise specified, "thickness" refers to a value expressed as the average of thicknesses measured at five randomly selected points on the object, and can be obtained using a constant pressure thickness measuring device in accordance with JIS K7130.

[0071] <<Composition for forming protective film>> The protective film-forming film can be formed using a protective film-forming composition containing its constituent materials. For example, the protective film-forming film can be formed by applying the protective film-forming composition to the surface to be formed and drying it as necessary. The ratio of the contents of the components that do not vaporize at room temperature in the protective film-forming composition is usually the same as the ratio of the contents of the components in the protective film-forming film. In this specification, "room temperature" means a temperature that is not particularly cooled or heated, that is, an ordinary temperature, and examples thereof include a temperature of 18 to 28°C.

[0072] In the protective film-forming film, the ratio of the total content of one or more components contained in the protective film, which will be described later, to the total mass of the protective film-forming film is 100 mass % or less. Similarly, in the composition for forming a protective film, the ratio of the total content of one or more components contained in the composition for forming a protective film, which will be described later, to the total mass of the composition for forming a protective film is 100 mass % or less.

[0073] The protective film-forming composition can be applied by a known method such as a method using various coaters.

[0074] The drying conditions for the protective film-forming composition are not particularly limited as long as the composition itself and the thermosetting protective film-forming film formed from the composition are not thermally cured. When the protective film-forming composition contains a solvent described below, it is preferably dried by heating, and more preferably dried by heating at 70 to 130°C for 10 seconds to 5 minutes.

[0075] The thermosetting protective film-forming film, the energy ray-curable protective film-forming film, and the non-curable protective film-forming film will be described below in this order.

[0076] <Thermosetting protective film-forming film, thermosetting protective film-forming composition (III)> The curing conditions when the thermosetting protective film-forming film is thermally cured to form a protective film are not particularly limited, as long as the degree of curing is such that the protective film can fully exhibit its functions. For example, the heating temperature during thermal curing of the thermosetting protective film-forming film is preferably 100 to 200° C., and may be, for example, any one of 110 to 170° C. and 120 to 150° C. The heating time during thermal curing is preferably 0.5 to 5 hours, and may be, for example, any one of 0.5 to 4 hours and 1 to 3 hours.

[0077] A preferred example of a thermosetting protective film-forming film is one containing a polymer component (A), a thermosetting component (B), a thermosetting agent (C), a filler (E), and a colorant (J). Such a thermosetting protective film-forming film can be formed using a thermosetting protective film-forming composition (III) (sometimes abbreviated herein simply as "composition (III)") containing the polymer component (A), the thermosetting component (B), the thermosetting agent (C), the filler (E), and the colorant (J).

[0078] The polymer component (A), thermosetting component (B), thermosetting agent (C), filler (E) and colorant (J) contained in the composition (III) and the thermosetting protective film-forming film may each be one type only or two or more types, and if there are two or more types, their combination and ratio can be selected arbitrarily.

[0079] [Polymer component (A)] The polymer component (A) is a component that can be considered to be formed by the polymerization reaction of a polymerizable compound, and is a component that imparts film-forming properties, flexibility, toughness, ductility, etc. to the thermosetting protective film-forming film, and that imparts flexibility, toughness, ductility, etc. to the protective film. In this specification, the polymerization reaction also includes a polycondensation reaction.

[0080] Examples of the polymer component (A) include acrylic resins, urethane resins, phenoxy resins, silicone resins, saturated polyester resins, etc., with acrylic resins being preferred.

[0081] The acrylic resin in the polymer component (A) may be any known acrylic polymer. The weight-average molecular weight (Mw) of the acrylic resin is preferably 10,000 to 2,000,000, and may be, for example, any one of 100,000 to 1,500,000, 150,000 to 1,200,000, and 200,000 to 1,000,000. When the weight-average molecular weight of the acrylic resin is equal to or greater than the lower limit, the shape stability (stability over time during storage) of the protective film-forming film is improved. When the weight-average molecular weight of the acrylic resin is equal to or less than the upper limit, the protective film-forming film can more easily conform to the uneven surface of the adherend.

[0082] In this specification, unless otherwise specified, the "weight average molecular weight" is a polystyrene equivalent value measured by gel permeation chromatography (GPC).

[0083] The glass transition temperature (Tg) of the acrylic resin is preferably 0 to 70°C, and may be, for example, any of 0 to 50°C, 0 to 30°C, and 0 to 10°C. When the Tg of the acrylic resin is equal to or greater than the lower limit, adhesion between the protective film and the support sheet described below is suppressed, and the releasability of the support sheet is appropriately improved. When the Tg of the acrylic resin is equal to or less than the upper limit, the protective film-forming film can easily conform to the uneven surface of the adherend.

[0084] When an acrylic resin has two or more structural units, the glass transition temperature (Tg) of the acrylic resin can be calculated using the Fox equation. The Tg of the homopolymer of the monomer from which the structural units are derived can be calculated using values ​​listed in the Polymer Data Handbook, Adhesive Handbook, or Polymer Handbook.

[0085] Examples of acrylic resins include polymers of one or more (meth)acrylic acid esters; copolymers of two or more monomers selected from the above-mentioned (meth)acrylic acid esters, (meth)acrylic acid, itaconic acid, vinyl acetate, acrylonitrile, styrene, and N-methylolacrylamide.

[0086] Examples of the (meth)acrylic acid ester constituting the acrylic resin include (meth)acrylic acid alkyl esters in which the alkyl group constituting the alkyl ester has a chain structure and has 1 to 18 carbon atoms, such as methyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate; (Meth)acrylic acid cycloalkyl esters such as dicyclopentanyl (meth)acrylate; glycidyl group-containing (meth)acrylic acid esters such as glycidyl (meth)acrylate; Examples include hydroxyl group-containing (meth)acrylic acid esters such as 2-hydroxyethyl (meth)acrylate.

[0087] In this specification, the term "(meth)acrylic acid" is a concept that encompasses both "acrylic acid" and "methacrylic acid." The same applies to terms similar to (meth)acrylic acid.

[0088] The acrylic resin may be made up of one type of monomer or two or more types of monomers, and when two or more types of monomers are used, the combination and ratio thereof can be selected arbitrarily.

[0089] The acrylic resin may or may not have a functional group capable of bonding to other compounds, such as a vinyl group, a (meth)acryloyl group, an amino group, a hydroxyl group, a carboxy group, an isocyanate group, etc. The functional group of the acrylic resin may bond to other compounds via a crosslinking agent (G) described below, or may bond directly to other compounds without the crosslinking agent (G).

[0090] As the polymer component (A), thermoplastic resins other than acrylic resins, such as polyester, polyurethane, phenoxy resin, polybutene, polybutadiene, and polystyrene, may also be used.

[0091] In composition (III), the proportion of the content of polymer component (A) relative to the total content of all components other than the solvent is preferably 10 to 85 mass %, regardless of the type of polymer component (A), and may be, for example, either 10 to 55 mass % or 10 to 25 mass %. This is equivalent to saying that in the thermosetting protective film-forming film, the content ratio of the polymer component (A) relative to the total mass of the thermosetting protective film-forming film is preferably 10 to 85 mass% regardless of the type of polymer component (A), and may be, for example, either 10 to 55 mass% or 10 to 25 mass%. This is based on the fact that in the process of removing the solvent from a solvent-containing resin composition to form a resin film, the amount of components other than the solvent usually does not change, and the content ratio of the components other than the solvent is the same between the resin composition and the resin film. Therefore, in this specification, not only in the case of the protective film-forming film, but also with respect to the content of the components other than the solvent, only the content in the resin film obtained by removing the solvent from the resin composition will be described.

[0092] [Thermosetting component (B)] The thermosetting component (B) has thermosetting properties and is a component for curing the thermosetting protective film-forming film. Examples of the thermosetting component (B) include epoxy-based thermosetting resins, thermosetting polyimide resins, and unsaturated polyester resins, with epoxy-based thermosetting resins being preferred. In this specification, the term "thermosetting polyimide resin" is a general term for a polyimide precursor that forms a polyimide resin by thermal curing, and a thermosetting polyimide.

[0093] Examples of the epoxy resin include known epoxy resins, such as bifunctional or higher functional epoxy compounds, including polyfunctional epoxy resins, biphenyl compounds, bisphenol A diglycidyl ether and its hydrogenated products, orthocresol novolac epoxy resins, dicyclopentadiene-type epoxy resins, biphenyl-type epoxy resins, bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, and phenylene skeleton-type epoxy resins. The epoxy resin may have an unsaturated hydrocarbon group.

[0094] The number average molecular weight of the epoxy resin is not particularly limited, but is preferably 300 to 30,000 in terms of the curability of the thermosetting protective film-forming film and the strength and heat resistance of the protective film that is the cured product thereof. The epoxy equivalent of the epoxy resin is preferably 100 to 1000 g / eq, and may be, for example, either 150 to 600 g / eq or 150 to 400 g / eq.

[0095] [Thermal hardener (C)] When the thermosetting component (B) is an epoxy resin, the composition (III) and the thermosetting protective film-forming film preferably contain a thermosetting agent (C). Examples of the thermosetting agent (C) include compounds having two or more functional groups per molecule that can react with epoxy groups, such as phenolic hydroxyl groups, alcoholic hydroxyl groups, amino groups, carboxyl groups, and anhydride groups of acid groups.

[0096] Among the heat curing agents (C), examples of phenolic curing agents having a phenolic hydroxyl group include polyfunctional phenolic resins, biphenols, novolac-type phenolic resins, dicyclopentadiene-type phenolic resins, and aralkyl-type phenolic resins. Among the heat curing agents (C), examples of amine-based curing agents having an amino group include dicyandiamide.

[0097] Of the thermosetting agents (C), the number average molecular weight of resin components such as polyfunctional phenolic resins, novolac-type phenolic resins, dicyclopentadiene-type phenolic resins, and aralkyl-type phenolic resins is preferably 300 to 30,000, and may be, for example, any of 400 to 10,000 and 500 to 3,000. Of the thermosetting agent (C), the molecular weight of the non-resin components such as biphenol and dicyandiamide is not particularly limited, but is preferably 60 to 500, for example.

[0098] In the composition (III) and the thermosetting protective film-forming film, the content of the thermosetting agent (C) is preferably 0.1 to 100 parts by mass relative to 100 parts by mass of the content of the thermosetting component (B), and may be, for example, any of 0.5 to 50 parts by mass, 0.5 to 25 parts by mass, 0.5 to 12 parts by mass, and 0.5 to 5 parts by mass. When the content of the thermosetting agent (C) is equal to or greater than the lower limit, curing of the thermosetting protective film-forming film proceeds more easily. When the content of the thermosetting agent (C) is equal to or less than the upper limit, the moisture absorption rate of the thermosetting protective film-forming film is reduced, and the adhesive reliability of the protective film to the adherend is further improved.

[0099] In the thermosetting protective film-forming film, the ratio of the total content of the thermosetting component (B) and the thermosetting agent (C) to the total mass of the thermosetting protective film-forming film is preferably 5 to 40 mass%, and may be, for example, any of 5 to 30 mass%, 5 to 20 mass%, 10 to 40 mass%, 13 to 40 mass%, or 10 to 30 mass%. When the ratio is within this range, the protective effect of the protective film and the adhesive reliability of the protective film to the adherend are further improved. Furthermore, the adhesion between the protective film and the support sheet described below is appropriately suppressed, improving the releasability of the support sheet.

[0100] [Filler (E)] By including the filler (E) in the thermosetting protective film-forming film, it becomes easy to adjust the thermal expansion coefficient of the thermosetting protective film-forming film and its cured product (protective film), and by optimizing this thermal expansion coefficient for the object on which the protective film is formed, the adhesive reliability of the protective film to the adherend is further improved. Furthermore, by including the filler (E) in the thermosetting protective film-forming film, it is also possible to reduce the moisture absorption rate of the protective film and improve heat dissipation.

[0101] The filler (E) may be either an organic filler or an inorganic filler, but is preferably an inorganic filler. Preferred inorganic fillers include, for example, powders of silica, alumina, talc, red iron oxide, silicon carbide, boron nitride, etc.; beads obtained by spheronizing these inorganic fillers; surface-modified products of these inorganic fillers; single-crystal fibers of these inorganic fillers; glass fibers, etc. In addition, when a surface-modified product of an inorganic filler exists, in this specification, unless otherwise specified, the term "inorganic filler" is used to encompass "non-surface-modified inorganic fillers" and "surface-modified inorganic fillers." For example, "silica" means "either one or both of non-surface-modified silica and surface-modified silica" unless otherwise specified. Among these, the inorganic filler is preferably silica or alumina, and more preferably silica.

[0102] In the composition (III), in terms of improving the dispersibility of the filler (E) in the other components, the filler (E) is preferably silica, more preferably a surface-modified silica, even more preferably silica surface-modified with an organic group (organic compound), still more preferably silica surface-modified with a vinyl group, an epoxy group, a phenyl group, or a methacryl group, and particularly preferably silica surface-modified with a vinyl group or an epoxy group.

[0103] In the composition (III), the average particle size of the filler (E) is preferably 0.02 to 2 μm, more preferably 0.05 to 1 μm, and particularly preferably 0.07 to 0.7 μm, in order to improve the dispersibility of the filler (E) in the other components. In this specification, unless otherwise specified, the term "average particle size" refers to the particle size at 50% of the integrated value in the particle size distribution curve obtained by the laser diffraction scattering method (D 50 ) value.

[0104] In the thermosetting protective film-forming film, the content ratio of the filler (E) relative to the total mass of the thermosetting protective film-forming film is preferably 65 mass% or less, and may be, for example, any of 55 mass% or less, 45 mass% or less, 35 mass% or less, 25 mass% or less, and 20 mass% or less. When the ratio is equal to or less than the upper limit, the thermal expansion coefficient, moisture absorption rate, heat dissipation property, etc. of the protective film can be adjusted, and the effect of suppressing unintended peeling of the protective film and the workpiece is enhanced. On the other hand, there is no particular limitation on the lower limit of the proportion. For example, when the proportion is 5% by mass or more, the effect obtained by using the filler (E) becomes greater.

[0105] Colorant (J) The colorant (J) is a component for adjusting the light reflectance and light absorptance of the thermosetting protective film-forming film and the protective film. Examples of the colorant (J) include known ones such as inorganic pigments, organic pigments, and organic dyes.

[0106] Examples of the colorant (J) include white pigments, components that exhibit light absorbing properties (sometimes referred to as "light absorbers" in this specification), and other colorants that do not fall into any of these categories.

[0107] The thermosetting protective film-forming film preferably contains a white pigment, since this increases the reflectance of the thermosetting protective film-forming film and its cured product to light (420 to 700 nm).

[0108] Examples of the white pigment include titanium oxide (more specifically, titanium dioxide such as rutile titanium dioxide and anatase titanium dioxide), zinc oxide, zirconium oxide, magnesium oxide, calcium oxide, tin oxide, barium oxide, cesium oxide, yttrium oxide, magnesium carbonate, calcium carbonate (more specifically, light calcium carbonate, heavy calcium carbonate, etc.), barium carbonate, zinc carbonate, aluminum hydroxide, calcium hydroxide, magnesium hydroxide, zinc hydroxide, aluminum silicate, magnesium silicate, calcium silicate, barium sulfate, calcium sulfate, barium stearate, zinc white, zinc sulfide, talc, clay, kaolin, titanium phosphate, mica, gypsum, white carbon, diatomaceous earth, bentonite, lithopone, zeolite, sericite, and hydrated halloysite.

[0109] The white pigment may be any of the above exemplified white pigments, the surface of which has been treated with a surface treatment agent such as an inorganic compound having a hydroxyl group or an organic compound having a hydroxyl group or a carboxyl group (surface-treated product). In composition (III), such a surface-treated white pigment has high dispersibility in the other components, and in this case, the properties of composition (III) are improved.

[0110] Among the above, the white pigment is preferably titanium oxide or a surface-treated titanium oxide product.

[0111] When the thermosetting protective film-forming film contains a white pigment, the average particle size of the white pigment is preferably 0.05 to 2 μm, more preferably 0.1 to 1 μm, and even more preferably 0.2 to 0.7 μm, from the viewpoints of improving the dispersibility of the white pigment in the other components in the composition (III) and efficiently increasing the reflectance of light (420 to 700 nm). In the case of a white pigment that is a surface-treated product, the portion derived from the surface treatment agent is also considered to be part of the particle, and the particle size of the white pigment including the portion derived from the surface treatment agent is specified, and the average particle size of the white pigment is calculated based on the particle size.

[0112] When the thermosetting protective film-forming film contains a white pigment as the colorant (J), the ratio of the content of the white pigment in the thermosetting protective film-forming film to the total mass of the thermosetting protective film-forming film is the same as the ratio of the content of the white pigment in the protective film-forming film to the total mass of the protective film-forming film described above. The effects in this case are also as described above.

[0113] When the composition (III) and the protective film-forming film contain at least a white pigment as the colorant (J), the ratio of the content of the white pigment to the total content of the colorant (J) (the total content of the white pigment and colorants other than the white pigment) in the composition (III) and the protective film-forming film is preferably 90 to 99.9 mass%, more preferably 93 to 99.9 mass%, and may be, for example, either 95 to 99.9 mass% or 97 to 99.9 mass%. When the ratio is equal to or greater than the lower limit, the effect of using the white pigment is enhanced. When the ratio is equal to or less than the upper limit, the effect of using a colorant other than the white pigment (for example, the light absorbing agent or the other colorant) is enhanced.

[0114] The thermosetting protective film-forming film preferably contains the light absorber, since the thermosetting protective film-forming film and its cured product have higher light (532 nm) absorptance and light (1064 nm) absorptance.

[0115] Examples of light absorbers include carbon materials such as carbon black; black pigments other than carbon black; xanthene-based dyes (dyes having a xanthene ring); and metal oxides.

[0116] Examples of commercially available light absorbers useful for increasing the absorbance of light (532 nm) include an organic black pigment (6377 Black, manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd.) and a xanthene dye (Polymerizable Dye Fluorescent Purple R13, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), which will be described later in the Examples. Examples of commercially available light absorbers useful for increasing the absorptivity of light (1064 nm) include antimony-doped tin oxide ("Iriotec (registered trademark) 8817" manufactured by Merck Performance Materials) which will be described later in the Examples section. Examples of light absorbing agents that are useful for increasing the absorptivity of both light (532 nm) and light (1064 nm) include carbon black.

[0117] When the thermosetting protective film-forming film contains a light absorber as the colorant (J), the ratio of the content of the light absorber in the thermosetting protective film-forming film to the total mass of the thermosetting protective film-forming film is the same as the ratio of the content of the light absorber in the protective film-forming film to the total mass of the protective film-forming film, as explained above. The effects in this case are also as explained above.

[0118] The composition (III) and the thermosetting protective film-forming film may or may not contain other components other than the polymer component (A), the thermosetting component (B), the thermosetting agent (C), the filler (E) and the colorant (J). Examples of the other components include a curing accelerator (D), a coupling agent (F), a crosslinking agent (G), an energy ray-curable component (H), a photopolymerization initiator (I), and a general-purpose additive (K).

[0119] The curing accelerator (D), coupling agent (F), crosslinking agent (G), energy ray curable component (H), photopolymerization initiator (I) and general-purpose additive (K) contained in the composition (III) and the thermosetting protective film-forming film may each be one type only or two or more types, and when there are two or more types, the combination and ratio thereof can be selected arbitrarily.

[0120] [Curing accelerator (D)] The curing accelerator (D) is a component for adjusting the curing rate of the thermosetting protective film-forming film. Preferred examples of the curing accelerator (D) include imidazoles (imidazoles in which one or more hydrogen atoms are substituted with groups other than hydrogen atoms) such as 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, and 2-phenyl-4-methyl-5-hydroxymethylimidazole; tertiary amines; organic phosphines (phosphines in which one or more hydrogen atoms are substituted with organic groups); and tetraphenylboron salts.

[0121] When the curing accelerator (D) is used, the content of the curing accelerator (D) in the thermosetting protective film-forming film is preferably 0.01 to 10 parts by mass, and may be, for example, 0.1 to 7 parts by mass or 0.5 to 5 parts by mass, relative to 100 parts by mass of the total content of the thermosetting component (B) and the thermosetting agent (C). When the content of the curing accelerator (D) is equal to or greater than the lower limit, the effect of using the curing accelerator (D) is more pronounced. When the content of the curing accelerator (D) is equal to or less than the upper limit, for example, the effect of suppressing the highly polar curing accelerator (D) from migrating to the adhesive interface with the adherend and segregating in the thermosetting protective film-forming film under high temperature and high humidity conditions is enhanced. As a result, the adhesive reliability of the protective film to the adherend is further improved.

[0122] [Coupling agent (F)] By using a coupling agent (F) having a functional group capable of reacting with an inorganic compound or an organic compound, the adhesive reliability of the protective film to the adherend can be improved.

[0123] The coupling agent (F) is preferably a compound having a functional group capable of reacting with the functional group of the polymer component (A), the thermosetting component (B), etc., and is more preferably a silane coupling agent.

[0124] Preferred examples of the silane coupling agent include 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropylmethyldiethoxysilane, 3-glycidyloxypropyltriethoxysilane, and 3-glycidyloxymethyldiethoxysilane.

[0125] Preferred examples of the silane coupling agent include oligomeric silane coupling agents having multiple alkoxysilyl groups in one molecule. The oligomeric silane coupling agent is preferred in that it is less likely to volatilize and has multiple alkoxysilyl groups in one molecule, making it effective in improving the durability of the protective film. Examples of the oligomeric silane coupling agents include epoxy group-containing oligomeric silane coupling agents "X-41-1053," "X-41-1059A," "X-41-1056," and "X-40-2651" (all manufactured by Shin-Etsu Chemical Co., Ltd.); and mercapto group-containing oligomeric silane coupling agents "X-41-1818," "X-41-1810," and "X-41-1805" (all manufactured by Shin-Etsu Chemical Co., Ltd.).

[0126] When a coupling agent (F) is used, the content of the coupling agent (F) in the composition (III) and the thermosetting protective film-forming film is preferably 0.03 to 5 parts by mass, and may be, for example, 0.03 to 3 parts by mass or 0.03 to 1 part by mass, relative to 100 parts by mass of the total content of the polymer component (A), the thermosetting component (B), and the thermosetting agent (C). When the content of the coupling agent (F) is equal to or greater than the lower limit, the effects of using the coupling agent (F), such as improved dispersibility of the filler (E) in the resin and improved adhesion reliability of the protective film to the adherend, are more significantly obtained. When the content of the coupling agent (F) is equal to or less than the upper limit, outgassing is further suppressed.

[0127] [Crosslinker (G)] When the polymer component (A) is the above-mentioned acrylic resin or the like and has a functional group capable of bonding with other compounds, such as a vinyl group, a (meth)acryloyl group, an amino group, a hydroxyl group, a carboxyl group, or an isocyanate group, the crosslinking agent (G) bonds the functional group in the polymer component (A) with other compounds to crosslink them. In this case, the adhesive strength and cohesive strength of the protective film-forming film can be adjusted.

[0128] Examples of the crosslinking agent (G) include organic polyvalent isocyanate compounds, organic polyvalent imine compounds, metal chelate crosslinking agents (crosslinking agents having a metal chelate structure), and aziridine crosslinking agents (crosslinking agents having an aziridinyl group).

[0129] When a crosslinking agent (G) is used, the content of the crosslinking agent (G) in the composition (III) is preferably 0.01 to 20 parts by mass, more preferably 0.1 to 10 parts by mass, and even more preferably 0.5 to 5 parts by mass, per 100 parts by mass of the polymer component (A). When the content of the crosslinking agent (G) is equal to or greater than the lower limit, the effect of using the crosslinking agent (G) is more pronounced. When the content of the crosslinking agent (G) is equal to or less than the upper limit, excessive use of the crosslinking agent (G) is suppressed.

[0130] [Energy ray curable component (H)] The thermosetting protective film-forming film contains the energy ray-curable component (H), and thus its properties can be changed by irradiation with energy rays.

[0131] The energy ray-curable component (H) is an energy ray-curable compound, or an energy ray-curable oligomer or polymer (polymer) that can be considered to have been synthesized from an energy ray-curable compound. Examples of the energy ray-curable compound include compounds having at least one polymerizable double bond in the molecule, and acrylate compounds having a (meth)acryloyl group are preferred.

[0132] When the energy ray-curable component (H) is used, the content of the energy ray-curable component (H) in the thermosetting protective film-forming film is preferably 1 to 20 mass% relative to the total mass of the thermosetting protective film-forming film. When the content is within this range, the effects of using the energy ray-curable component (H) can be satisfactorily obtained without impairing other properties of the thermosetting protective film-forming film.

[0133] It is preferable that the thermosetting protective film-forming film does not substantially contain an energy ray (e.g., ultraviolet ray) curable component. Even when such a thermosetting protective film-forming film is irradiated with energy rays, no change in physical properties due to curing, such as an increase in the elastic modulus of the thermosetting protective film-forming film at room temperature, is substantially observed. Furthermore, even if such a thermosetting protective film-forming film has the property of reflecting energy rays, it can form a cured product with a sufficient degree of curing by curing only by heat curing without the need for energy ray irradiation. In this specification, "the protective film-forming film does not substantially contain an energy ray-curable component" means that the content of the energy ray-curable component in the protective film-forming film is 0 to 0.3 mass% relative to the total mass of the protective film-forming film.

[0134] [Photopolymerization initiator (I)] The photopolymerization initiator (I) is a component for efficiently promoting the polymerization reaction of the energy ray-curable component (H). The photopolymerization initiator (I) may be a known one. When the photopolymerization initiator (I) is used, the content of the photopolymerization initiator (I) in the composition (III) and the thermosetting protective film-forming film is preferably 0.1 to 20 parts by mass per 100 parts by mass of the content of the energy ray-curable component (H).

[0135] [General Purpose Additives (K)] The general-purpose additive (K) may be a known one and can be selected arbitrarily depending on the purpose, without any particular limitation. Preferable general-purpose additives (K) include, for example, plasticizers, antistatic agents, antioxidants, gettering agents, ultraviolet absorbers, and tackifiers. The content of the general-purpose additive (K) in the composition (III) and the thermosetting protective film-forming film is not particularly limited and may be appropriately selected depending on the purpose.

[0136] [solvent] Composition (III) preferably further contains a solvent, which improves the handleability of composition (III). In this specification, unless otherwise specified, the term "solvent" is used to refer to a concept that includes not only a substance that dissolves a target component, but also a dispersion medium that disperses the target component.

[0137] The solvent is not particularly limited, but preferred examples include hydrocarbons such as toluene; alcohols such as methanol; esters such as ethyl acetate; ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran; and amides (compounds having an amide bond) such as dimethylformamide and N-methylpyrrolidone. The composition (III) may contain only one type of solvent, or two or more types. When two or more types are contained, the combination and ratio thereof can be selected arbitrarily.

[0138] The content of the solvent in the composition (III) is not particularly limited, and may be appropriately selected depending on, for example, the types of components other than the solvent.

[0139] <Method for producing a thermosetting protective film-forming composition> A thermosetting composition for forming a protective film such as composition (III) can be obtained by blending the components that constitute the composition. The temperature and time for adding and mixing each component are not particularly limited as long as the components do not deteriorate, and may be adjusted appropriately. A temperature of 15 to 30°C is preferred.

[0140] <Energy ray-curable protective film-forming film, energy ray-curable protective film-forming composition (IV)> The curing conditions when the energy ray-curable protective film-forming film is cured with energy rays to form a protective film are not particularly limited as long as the degree of curing is such that the protective film can fully exhibit its functions. For example, the irradiance of the energy ray during energy ray curing of the energy ray curable protective film-forming film is 60 to 320 mW / cm 2 The amount of energy rays during the curing is preferably 100 to 1000 mJ / cm. 2 It is preferable that:

[0141] A preferred example of the energy ray-curable protective film-forming film is one containing an energy ray-curable component (a), a filler, and a colorant. Such an energy ray-curable protective film-forming film can be formed using an energy ray-curable protective film-forming composition (IV) (sometimes abbreviated herein simply as "composition (IV)") containing the energy ray-curable component (a), a filler, and a colorant.

[0142] The composition (IV) and the energy ray-curable protective film-forming film may or may not contain other components other than the energy ray-curable component (a), the filler, and the colorant. Examples of the other components include a polymer (b) having no energy ray-curable group, a coupling agent, a crosslinking agent, a photopolymerization initiator, and general-purpose additives.

[0143] Examples of the energy ray-curable component (a), the polymer (b) not having an energy ray-curable group, the filler, the colorant, the coupling agent, the crosslinking agent, the photopolymerization initiator and the general-purpose additives include the same as those contained in the composition (III) and the thermosetting protective film-forming film, namely, the energy ray-curable component (H), the polymer component (A) not having an energy ray-curable group, the filler (E), the colorant (J), the coupling agent (F), the crosslinking agent (G), the photopolymerization initiator (I) and the general-purpose additive (K).

[0144] The content of each of the above-mentioned components in the composition (IV) and the energy ray-curable protective film-forming film may be adjusted appropriately depending on the purpose.

[0145] Composition (IV) preferably further contains a solvent similar to that used in composition (III), since dilution improves its handling properties.

[0146] The energy ray-curable protective film-forming composition such as composition (IV) can be obtained by blending the components that constitute it. The energy ray-curable composition for forming a protective film can be produced in the same manner as the heat-curable composition for forming a protective film described above, except that the types of ingredients used are different.

[0147] <Non-curable protective film-forming film, non-curable protective film-forming composition (V)> A preferred non-curable protective film-forming film includes, for example, one containing a polymer component, a filler, and a colorant. Such a non-curable protective film-forming film can be formed using a non-curable protective film-forming composition (V) (sometimes abbreviated herein simply as "composition (V)") containing the polymer component, a filler, and a colorant.

[0148] The composition (V) and the non-curable protective film-forming film may or may not contain other components other than the polymer component, filler, and colorant. Examples of the other components include coupling agents, crosslinking agents, and general-purpose additives.

[0149] The polymer component, filler, colorant, coupling agent, crosslinking agent and general-purpose additive may be the same as the polymer component (A), filler (E), colorant (J), coupling agent (F), crosslinking agent (G) and general-purpose additive (K) contained in the composition (III) and the thermosetting protective film-forming film, respectively.

[0150] The content of each of the above-mentioned components in the composition (V) and the non-curable protective film-forming film may be adjusted appropriately depending on the purpose.

[0151] Composition (V) preferably further contains a solvent similar to that used in composition (III), since dilution improves its handling properties.

[0152] A non-curable protective film-forming composition such as composition (V) can be obtained by blending the components that constitute it. The non-curable protective film-forming composition can be produced in the same manner as the thermosetting protective film-forming composition described above, except that the types of ingredients used are different.

[0153] ◎Examples of protective film forming films A preferred example of the protective film-forming film is a protective film-forming film for forming a protective film on any part of a workpiece obtained by processing a workpiece, the protective film-forming film is a thermosetting protective film-forming film containing a polymer component (A), a thermosetting component (B), a thermosetting agent (C), a filler (E), and a colorant (J), The protective film-forming film may be such that the reflectance of the heat-cured product of the protective film-forming film over the entire wavelength range of 420 to 700 nm is 22% or more, and the absorbance of the heat-cured product of the protective film-forming film over either or both of the wavelengths of 532 nm and 1064 nm is 7% or more. Such a protective film-forming film contains a white pigment and a light absorber as the colorant (J), and in the protective film-forming film, the content ratio of the white pigment relative to the total mass of the protective film-forming film is 0.8 mass% or more, and in the protective film-forming film, the content ratio of the light absorber relative to the total mass of the protective film-forming film is 0.7 mass% or less, In the protective film-forming film, it is preferable that the content ratio of the filler (E) to the total mass of the protective film-forming film is 65 mass% or less (however, in the protective film-forming film, the total content ratio of the polymer component (A), thermosetting component (B), thermosetting agent (C), filler (E) and colorant (J) to the total mass of the protective film-forming film does not exceed 100 mass%). Furthermore, in such a protective film-forming film, it is preferable that the content ratio of the polymer component (A) relative to the total mass of the protective film-forming film is 10 to 85 mass%, the total content ratio of the thermosetting component (B) and the thermosetting agent (C) is 5 to 40 mass%, and the content of the thermosetting agent (C) is 0.1 to 100 mass parts per 100 mass parts of the thermosetting component (B) (however, in the protective film-forming film, the total content ratio of the polymer component (A), the thermosetting component (B), the thermosetting agent (C), the filler (E) and the colorant (J) relative to the total mass of the protective film-forming film does not exceed 100 mass%). Furthermore, when such a protective film-forming film contains a carbon material as the light absorber, it is preferable that the content ratio of the carbon material in the protective film-forming film to the total mass of the protective film-forming film is 0.1 mass% or less.

[0154] 1 is a cross-sectional view schematically illustrating an example of a protective film-forming film according to one embodiment of the present invention. In addition, in the drawings used in the following description, for the sake of convenience, in order to make the features of the present invention easier to understand, the main parts may be shown enlarged, and the dimensional ratios of each component may not necessarily be the same as in reality.

[0155] The protective film-forming film 13 shown here has a first release film 151 on one surface (sometimes referred to herein as the "first surface") 13a thereof, and a second release film 152 on the other surface (sometimes referred to herein as the "second surface") 13b opposite the first surface 13a. By providing the protective film-forming film 13 with the first release film 151 and the second release film 152, adhesion of foreign matter to the first surface 13a and the second surface 13b of the protective film-forming film 13 is suppressed. However, the release film has an optional configuration, and the protective film-forming film 13 does not necessarily have to have either the first release film 151 or the second release film 152. Such a protective film-forming film 13 is suitable for storage in a roll form, for example.

[0156] When the protective film-forming film 13 is curable, the reflectance of the cured product of the protective film-forming film 13 for light in the entire wavelength range of 420 to 700 nm is 22% or more, and the absorptance of the cured product for light at either or both wavelengths of 532 nm and 1064 nm is 7% or more. When the protective film-forming film 13 is non-curable, the reflectance of the protective film-forming film 13 for light in the entire wavelength range of 420 to 700 nm is 22% or more, and the absorptance of the protective film-forming film 13 for light at either or both wavelengths of 532 nm and 1064 nm is 7% or more.

[0157] Both the first release film 151 and the second release film 152 may be a known release film, such as a polyethylene terephthalate film having a silicone release agent layer formed on one side thereof. The first release film 151 and the second release film 152 may be the same as or different from each other.

[0158] Either the first surface 13a or the second surface 13b of the protective film-forming film 13 becomes the surface to be attached to any location on the workpiece, and the other becomes the surface to be attached to the support sheet or processing sheet described below.

[0159] The protective film-forming film of this embodiment can be attached to any location on a workpiece without being used in combination with a support sheet described later, and on the other hand, by using it in combination with a support sheet described later, a composite sheet for forming a protective film can be configured for both forming a protective film and processing the workpiece. Such a composite sheet for forming a protective film will be described below.

[0160] ◇Composite sheet for forming protective film The composite sheet for forming a protective film comprises a support sheet and a protective film-forming film provided on one side of the support sheet, and the protective film-forming film is the protective film-forming film according to one embodiment of the present invention described above. The composite sheet for forming a protective film may be the same as a conventional composite sheet for forming a protective film, except that it includes the protective film-forming film of this embodiment.

[0161] In this specification, as long as the laminated structure of the support sheet and the cured product of the protective film-forming film is maintained even after the protective film-forming film has hardened, this laminated structure is referred to as a "composite sheet for forming a protective film."

[0162] ◎Support sheet Examples of the support sheet include known ones such as one comprising a substrate and a pressure-sensitive adhesive layer provided on one side of the substrate, one consisting of only a substrate, etc. When the support sheet comprises a pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer is disposed between the substrate and the protective film-forming film in the composite sheet for forming a protective film.

[0163] The support sheet preferably has optical transparency. For example, when the support sheet has transparency to light (532 nm) or light (1064 nm), printing can be performed on the protective film-forming film or its cured product by irradiating the protective film-forming film or its cured product with a laser (532 nm) or a laser (1064 nm) through the support sheet (through the support sheet), thereby making the protective film-forming composite sheet highly useful.

[0164] The substrate and the adhesive layer may each consist of one layer (single layer) or two or more layers. When consisting of multiple layers, these multiple layers may be the same or different from each other, and the combination of these multiple layers is not particularly limited.

[0165] ◎Other configurations The composite sheet for forming a protective film of this embodiment may further include, on the surface of the protective film-forming film opposite the support sheet side, either or both of a jig adhesive layer and a release film. The jig adhesive layer and release film may be known and have any configuration in the composite sheet for forming a protective film of this embodiment.

[0166] The jig adhesive layer is provided, for example, in an area near the peripheral edge of the surface of the protective film-forming film opposite to the support sheet side. The release film is provided on the side of the protective film-forming film opposite the support sheet side, and if the composite sheet for protective film formation has a jig adhesive layer, it is also provided on the side of the jig adhesive layer opposite the protective film-forming film side.

[0167] ○Base material The substrate is in the form of a sheet or film, and examples of the constituent materials thereof include various resins. The resin constituting the substrate may be one type only, or two or more types, and when two or more types are used, the combination and ratio thereof can be selected arbitrarily. Examples of the resin include polyolefins such as polyethylene and polypropylene; ethylene-based copolymers (copolymers obtained using ethylene as a monomer) such as ethylene-vinyl acetate copolymer, ethylene-(meth)acrylic acid copolymer, and ethylene-(meth)acrylic acid ester copolymer; polystyrene; polycycloolefins; and polyesters such as polyethylene terephthalate. The resin may be any of a polymer alloy such as a mixture of two or more of the above-mentioned resins, a crosslinked resin in which one or more of the above-mentioned resins are crosslinked, and a modified resin such as an ionomer using one or more of the above-mentioned resins.

[0168] The substrate may contain, in addition to the main constituent materials such as the resin, various known additives such as fillers, colorants, antioxidants, organic lubricants, catalysts, and softeners (plasticizers).

[0169] The thickness of the substrate is preferably 50 to 300 μm, more preferably 50 to 120 μm. When the thickness of the substrate is in this range, the flexibility of the composite sheet for forming a protective film and the suitability for attachment to a workpiece are further improved.

[0170] The substrate can be produced by a known method. For example, a substrate containing a resin can be produced by molding a resin composition containing the resin.

[0171] Adhesive layer The pressure-sensitive adhesive layer is in the form of a sheet or film and contains a pressure-sensitive adhesive resin. Examples of the adhesive resin include acrylic resin, urethane resin, rubber-based resin, silicone resin, epoxy-based resin, polyvinyl ether, polycarbonate, and ester-based resin.

[0172] The thickness of the pressure-sensitive adhesive layer is not particularly limited, but is preferably 1 to 100 μm, and more preferably 3 to 20 μm.

[0173] The pressure-sensitive adhesive layer may be either energy ray curable or non-energy ray curable.

[0174] The pressure-sensitive adhesive layer can be formed using a pressure-sensitive adhesive composition containing a pressure-sensitive adhesive resin. For example, the pressure-sensitive adhesive composition can be applied to a surface on which the pressure-sensitive adhesive layer is to be formed, and then dried as necessary, to form the pressure-sensitive adhesive layer at the desired location. The application and drying of the pressure-sensitive adhesive composition can be carried out, for example, by the same method as in the application and drying of the above-mentioned composition for forming a protective film.

[0175] The adhesive composition can be obtained by blending the adhesive resin and, if necessary, components other than the adhesive resin, which are components for constituting the adhesive composition. The pressure-sensitive adhesive composition can be produced by the same method as the above-described composition for forming a protective film, except that the types of ingredients used are different.

[0176] ◇Manufacturing method of composite sheet for forming protective film The composite sheet for forming a protective film can be produced by laminating the above-mentioned layers in a corresponding positional relationship and adjusting the shapes of some or all of the layers as necessary. The method for forming each layer is as described above.

[0177] When producing a support sheet, for example, an adhesive composition is applied to a release film and dried as necessary to form an adhesive layer on the release film, and the exposed surface of this adhesive layer is then attached to one surface of the substrate, thereby laminating the adhesive layer on the substrate. When laminating a protective film-forming film on a substrate, for example, a protective film-forming composition is applied to a release film and dried as necessary to form a protective film-forming film on the release film, and the exposed surface of this protective film-forming film is then bonded to one surface of the substrate. When a protective film-forming film is to be laminated on top of an adhesive layer already laminated on a substrate, for example, a protective film-forming film may be formed in advance on a release film using a protective film-forming composition, and the exposed surface of this formed protective film-forming film may then be bonded to the exposed surface of the adhesive layer.

[0178] ◇Manufacturing method for workpieces with protective film (How to use protective film forming film) A method for manufacturing a workpiece with a protective film according to one embodiment of the present invention is a method for manufacturing a workpiece with a protective film using the protective film-forming film according to the embodiment of the present invention described above, in which if the protective film-forming film is curable, the cured product of the protective film-forming film is the protective film, and if the protective film-forming film is non-curable, the protective film after being attached to the workpiece is the protective film, and in the manufacturing method, the protective film-forming film is attached to the workpiece, printing is performed on the protective film-forming film or protective film after being attached to the workpiece, and the workpiece after being attached with the protective film-forming film is processed to produce the workpiece, and the protective film-forming film or protective film after being attached to the workpiece is cut, and if the protective film-forming film is curable, the protective film after being attached to the workpiece is further cured to form the protective film. In this way, the desired workpiece with a protective film is obtained. According to the manufacturing method of this embodiment, by using the protective film-forming film, a workpiece with a protective film can be obtained that is inconspicuous on a white substrate in a light-emitting device. The design of a device equipped with such a workpiece with a protective film is high. Furthermore, because the protective film formed from the protective film-forming film makes the workpiece with a protective film inconspicuous on a white substrate, even a protective film with high light reflectance can be printed in a sufficiently dark color on the protective film.

[0179] In the manufacturing method of this embodiment, after the protective film-forming film is attached to the workpiece, the order in which the steps of printing on the protective film-forming film or protective film, processing the workpiece, cutting the protective film-forming film or protective film, and hardening the curable protective film-forming film are performed is not particularly limited.

[0180] In each process after the protective film-forming film is attached to the workpiece, whether the protective film-forming film or the protective film is handled is determined by the timing of forming the protective film. If the protective film-forming film is non-curable, it is the protective film that is handled in each process after the protective film-forming film is attached to the workpiece. If the protective film-forming film is curable, it is the protective film-forming film that is handled before the protective film-forming film is cured, and it is the protective film that is handled after the protective film-forming film is cured.

[0181] The protective film-forming film may be one that does not constitute the composite sheet for forming a protective film and is attached to the workpiece, or one that is included in the composite sheet for forming a protective film and is attached to the workpiece.

[0182] The method for manufacturing a workpiece with a protective film of this embodiment may be the same as the method for manufacturing a workpiece with a conventional protective film, except that the protective film-forming film or protective film-forming composite sheet of this embodiment described above is used instead of the conventional protective film-forming film or protective film-forming composite sheet.

[0183] When the workpiece is a semiconductor wafer, the workpiece with a protective film is a semiconductor chip with a protective film comprising a semiconductor chip and a protective film provided on its back surface, and when the protective film-forming film is non-hardening, the protective film is the protective film after being attached to the back surface of the semiconductor wafer. In the method for manufacturing a semiconductor chip with a protective film, a protective film-forming film is attached to the back surface of a semiconductor wafer, and the workpiece is processed by dividing the semiconductor wafer into semiconductor chips.

[0184] In the above-described manufacturing method, when a protective film-forming film that does not constitute a composite sheet for forming a protective film is used, a processing sheet such as a dicing sheet is attached to the exposed surface (the surface opposite the workpiece) of the protective film-forming film or protective film after it has been attached to the workpiece, and then the workpiece is processed.

[0185] Printing on the protective film-forming film or protective film after it has been attached to the workpiece is performed on the side opposite the workpiece side. Such printing may be performed directly on a protective film-forming film or protective film that does not have a support sheet or processing sheet, or may be performed through the support sheet or processing sheet (over the support sheet or processing sheet) on a protective film-forming film or protective film that has a support sheet or processing sheet.

[0186] The printing is preferably performed using a laser beam in the long wavelength region having a wavelength of 532 nm or more, and more preferably using a laser (532 nm) or a laser (1064 nm). By using the protective film-forming film of this embodiment, it is possible to print in a sufficiently dark color on the protective film while maintaining a high light reflectance of the protective film.

[0187] For example, when printing with a laser (532 nm), the laser printing speed is preferably 50 to 300 mm / s and the laser frequency is preferably 3 to 40 kHz. The laser output can be selected arbitrarily, but is preferably 0.1 to 0.5 W, particularly when using a green laser marker manufactured by EO Tech. For example, when printing with a laser (1064 nm), the laser printing speed is preferably 100 to 700 mm / s and the laser frequency is preferably 3 to 20 kHz. The laser output can be selected arbitrarily, but is preferably 5 to 20 (device setting value, no unit), particularly when a fiber laser marker manufactured by SUNX is used as the laser marker. Regardless of whether a laser (532 nm) or a laser (1064 nm) is used, if a laser marker other than those described above is used, the laser output may be selected with reference to the above conditions.

[0188] The processing of the workpiece after the protective film-forming film is attached (production of the processed workpiece) can be performed by a known method depending on the type of workpiece. For example, if the workpiece is a semiconductor wafer, a known dicing method can be used as the processing method of the workpiece.

[0189] The protective film-forming film or protective film after being attached to the workpiece can be cut by a known method. For example, the cutting method can be selected taking into consideration the order in which the workpiece is processed and the protective film-forming film or protective film is cut. For example, when the workpiece is a semiconductor wafer, a known dicing method can be adopted, and the semiconductor wafer can be divided and the protective film-forming film or protective film can be cut consecutively.

[0190] When the protective film-forming film is curable, the protective film-forming film after being attached to the workpiece can be cured (the protective film is formed) by a known method, and the curing conditions are as described above.

[0191] In the manufacturing method, when a curable protective film-forming film is used, for example, the protective film-forming film is attached to a workpiece, the protective film-forming film is cured to form a protective film, printing is performed on the protective film, the workpiece is processed, and the protective film after printing is cut can be performed in any order. However, this is just one example of the manufacturing method, and the order in which each step is performed can be appropriately adjusted depending on the type of workpiece, the purpose, the method of performing each step, etc.

[0192] In the manufacturing method, other steps not corresponding to the above-mentioned steps (affixing the protective film-forming film to the workpiece, printing on the protective film-forming film or protective film, processing the workpiece, cutting the protective film-forming film or protective film, and hardening the protective film-forming film if the protective film-forming film is hardenable) may or may not be performed, as long as the effects of the present invention are not impaired. The types and timing of the other steps can be selected arbitrarily depending on the type of workpiece, the purpose, the method of performing each step, etc., and are not particularly limited.

[0193] The produced workpiece with the protective film can be picked up by separating it from the support sheet or processing sheet using a known method. The workpiece with the protective film will not stand out on the white substrate of the light-emitting device that will be mounted in the subsequent process, improving the design of the light-emitting device.

[0194] By using the protective film-forming film of this embodiment, even if the protective film has a high light reflectance, it is possible to print characters in a sufficiently dark color on the protective film. More specifically, for example, when the protective film is observed using an optical microscope (Keyence Corporation's "VHX-7000") under the conditions of white balance R = 1.77, G = 1.00, B = 2.31, ring illumination, brightness 100, magnification 100x, and shutter speed 1 / 120 sec, the printing characters on the protective film can be clearly seen. [Example]

[0195] The present invention will be described in more detail below with reference to specific examples, although the present invention is not limited to the examples shown below.

[0196] <Raw materials for producing the protective film-forming composition> The raw materials used in the production of the protective film-forming composition are shown below. [Polymer component (A)] (A)-1: An acrylic resin (weight average molecular weight: 450,000, glass transition temperature: 6°C) obtained by copolymerizing methyl acrylate (87 parts by mass) and 2-hydroxyethyl acrylate (13 parts by mass). [Thermosetting component (B)] (B)-1: Bisphenol A epoxy resin ("jER828" manufactured by Mitsubishi Chemical Corporation, epoxy equivalent: 184-194 g / eq) (B)-2: Dicyclopentadiene-type epoxy resin (DIC Corporation "Epicron HP-7200", epoxy equivalent 254-264g / eq) [Thermal hardener (C)] (C)-1: Dicyandiamide ("DICY7" manufactured by Mitsubishi Chemical Corporation) [Curing accelerator (D)] (D)-1:2-Phenyl-4,5-dihydroxymethylimidazole ("Curezol 2PHZ" manufactured by Shikoku Chemicals Corporation) [Filler (E)] (E)-1: Silica filler ("SC2050MB" manufactured by Admatechs Co., Ltd., silica filler surface-modified with an epoxy compound, average particle diameter 0.5 μm) [Coupling agent (F)] (F)-1: Oligomeric silane coupling agent having epoxy, methyl, and methoxy groups ("X-41-1056" manufactured by Shin-Etsu Chemical Co., Ltd., epoxy equivalent: 280 g / eq) [Crosslinker (G)] (G)-1: Tolylene diisocyanate trifunctional crosslinking agent (Mitsui Chemicals, Inc. "Takenate D-101E") Colorant (J) (J)-1: White pigment (rutile-type titanium dioxide surface-treated with an inorganic compound having a hydroxyl group, average particle size 0.35 μm) (J)-2: Organic black pigment (Dainichiseika Color & Chemicals Mfg. Co., Ltd. "6377 Black") (J)-3: Carbon material (carbon black, Mitsubishi Chemical Corporation "MA600", average particle size 20 nm) (J)-4: Xanthene dye (Fujifilm Wako Pure Chemical Industries, Ltd. "Polymerizable dye fluorescent purple R13") (J)-5: Laser marking pigment (antimony-doped tin oxide, "Iriotec (registered trademark) 8817" (Merck Performance Materials)

[0197] [Example 1] <<Protective Film Forming Film Manufacturing>> <Production of protective film-forming composition (III)> Each component was dissolved or dispersed in methyl ethyl ketone so that the type and content of the components contained in the protective film-forming film were as shown in Table 1, and the mixture was stirred at 23°C to obtain a thermosetting protective film-forming composition (III) having a total concentration of all components other than the solvent of 57 mass%.

[0198] <Production of protective film-forming film> A release film (second release film, "SP-PET50 2150" manufactured by Lintec Corporation, thickness 50 μm) made of polyethylene terephthalate film, one side of which had been treated for release by silicone treatment, was used, and the protective film-forming composition (III) obtained above was applied to the release-treated surface, followed by drying at 100°C for 2 minutes to produce a thermosetting protective film-forming film with a thickness of 25 μm.

[0199] Furthermore, the release-treated surface of a release film (first release film, "SP-PET38 1130" manufactured by Lintec Corporation, thickness 38 μm) was attached using a laminating roll to the exposed surface of the obtained protective film-forming film that was not provided with the second release film. As a result of the above, a laminated film was obtained comprising a protective film-forming film, a first release film provided on one side of the protective film-forming film, and a second release film provided on the other side of the protective film-forming film.

[0200] <<Evaluation of protective film forming films>> <Measurement of the reflectance of light (420 to 700 nm) of the cured protective film> One side of the silicon wafer was ground with a #2000 wheel to prepare a silicon wafer (thickness 350 μm) having a ground surface. The first release film was removed from the protective film-forming film in the laminated film obtained above, and the exposed surface of the protective film-forming film was attached to the ground surface of the silicon wafer using a roller heated to 70 ° C. at a lamination speed of 0.3 m / min. Next, the second release film was removed from the attached protective film-forming film, and the resulting silicon wafer with the protective film-forming film was heated at 140°C for 2 hours to thermally cure the protective film-forming film into a cured product, thereby obtaining a silicon wafer with a protective film.

[0201] The resulting silicon wafer with the protective film was allowed to cool to 23°C. The exposed surface of the cured product (the surface opposite the silicon wafer) was then measured for the total reflected light (specularly reflected light and diffusely reflected light) in the wavelength range of 380 to 800 nm at 1 nm intervals using the SCI method. The total reflected light was also measured using a barium sulfate reference plate in the same manner. In both cases, the total reflected light was measured using a UV-Vis spectrophotometer (Shimadzu Corporation, UV-VIS-NIR SPECTROPHOTOMETER UV-3600). A Shimadzu Corporation, Large Sample Chamber MPC-3100, was used as the sample holder, and a Shimadzu Corporation, Integrating Sphere Accessory ISR-3100, was used as the integrating sphere, with the incident angle of light on the measurement target set at 8°. Then, the ratio of the measured value of the cured product to the measured value of the reference plate ([measured value of the total light reflected light amount of the cured product of the protective film-forming film] / [measured value of the total light reflected light amount of the reference plate]×100), i.e., the relative total light reflectance of the cured product of the protective film-forming film, was calculated. Of the obtained relative total light reflectances, the value in the wavelength range of 420 to 700 nm was used as the reflectance of light (420 to 700 nm).

[0202] <Calculation of the difference between the maximum and minimum reflectance values ​​of light (420 to 700 nm) of the cured protective film-forming film> When measuring the reflectance of light (420 to 700 nm) of the cured product of the protective film-forming film, the maximum and minimum values ​​of the reflectance of light (420 to 700 nm) were read. These values ​​are shown in Table 3 together with the wavelength of the light in each case. Furthermore, the difference between these values ​​(difference between the maximum value and the minimum value) was calculated. The results are shown in the column "difference between the maximum value and the minimum value (%)" in Table 3.

[0203] <Measurement of reflectance of light (532 nm) and light (1064 nm) of the cured protective film-forming film> The first release film was removed from the protective film-forming film in the laminated film obtained above. Next, the protective film-forming film was heated at 140°C for 2 hours to be thermally cured to form a cured product (protective film). The cured product together with the second release film was allowed to cool to a temperature of 23°C, and the second release film was removed from the cured product to obtain a single-layer cured product.

[0204] For the surface of the single-layer cured product where the second release film was provided, the relative total light reflectance of the cured product of the protective film-forming film was determined in the same manner as in the above-mentioned "Measurement of the reflectance of light (420 to 700 nm) of the cured product of the protective film-forming film," except that the measurement wavelength range of the light amount of total reflected light was changed from 380 to 800 nm to 380 to 1600 nm. Of the obtained relative total light reflectances, the values ​​at wavelengths of 532 nm and 1064 nm were adopted as the reflectance of light (532 nm) and the reflectance of light (1064 nm), respectively.

[0205] <Measurement of the reflectance of light (420 to 700 nm) of protective film> The reflectance of light (420 to 700 nm) of the protective film-forming film was measured in the same manner as in the measurement of the above-mentioned "Reflectance of light (420 to 700 nm) of the cured product of the protective film-forming film," except that the protective film-forming film was not thermally cured and was used as is to measure the reflectance of light (420 to 700 nm).

[0206] <Calculation of the difference between the maximum and minimum reflectance values ​​of the protective film (420 to 700 nm)> When measuring the reflectance of light (420 to 700 nm) of the above protective film-forming film, the maximum and minimum values ​​of the reflectance of light (420 to 700 nm) were read. These values ​​are shown in Table 3 together with the wavelength of light in each case. Furthermore, the difference between these values ​​(difference between the maximum value and the minimum value) was calculated. The results are shown in the column "difference between the maximum value and the minimum value (%)" in Table 3.

[0207] <Measurement of the reflectance of light (532 nm) and light (1064 nm) of the protective film> The reflectance of light (532 nm) and the reflectance of light (1064 nm) of the protective film-forming film were measured in the same manner as in the above-mentioned "Measurement of the reflectance of light (532 nm) and the reflectance of light (1064 nm) of the cured product of the protective film-forming film," except that the protective film-forming film was not thermally cured and was used as is to measure the reflectance of light (532 nm) and the reflectance of light (1064 nm).

[0208] <Measurement of light (420 to 700 nm) transmittance and light (1064 nm) transmittance of the cured product of the protective film-forming film> In the same manner as in the above-mentioned "Measurement of reflectance of light (532 nm) and reflectance of light (1064 nm) of the cured product of the protective film-forming film", a single layer cured product was obtained. The light transmittance of this cured product was measured in 1 nm increments in the wavelength range of 380 to 1600 nm using a UV-Vis spectrophotometer (Shimadzu Corporation, "UV-VIS-NIR SPECTROPHOTOMETER UV-3600") and an integrating sphere (Shimadzu Corporation, "Integrating Sphere Accessory ISR-3100"). Of the measured values, the value in the wavelength range of 420 to 700 nm was used as the light transmittance (420 to 700 nm), and the values ​​at wavelengths of 532 nm and 1064 nm were used as the light transmittance (532 nm) and light transmittance (1064 nm), respectively. The maximum light transmittance (420 to 700 nm) is shown in Table 3.

[0209] <Measurement of light transmittance (420-700 nm) and light transmittance (1064 nm) of protective film> The light (420 to 700 nm) transmittance, light (532 nm) transmittance, and light (1064 nm) transmittance of the protective film-forming film were measured in the same manner as in the above-mentioned "Measurement of the light (420 to 700 nm) transmittance and light (1064 nm) transmittance of the cured product of the protective film-forming film" except that the protective film-forming film was not thermally cured and was used to measure the light (420 to 700 nm) transmittance as is. Of the measured values ​​obtained, the maximum light (420 to 700 nm) transmittance is shown in Table 3.

[0210] <Calculation of the light (532 nm) absorptance and light (1064 nm) absorptance of the cured protective film-forming film> Using the values ​​of the reflectance of light (532 nm) and the reflectance of light (1064 nm) of the cured product of the protective film-forming film obtained above, and the transmittance of light (532 nm) and the transmittance of light (1064 nm) of the cured product of the protective film-forming film, the absorptance of light (532 nm) and the absorptance of light (1064 nm) of the cured product of the protective film-forming film were calculated according to the formula (i). The results are shown in Table 3.

[0211] <Calculation of the absorbance of light (532 nm) and light (1064 nm) of the protective film> Using the values ​​of the reflectance of the protective film-forming film at light (532 nm) and the reflectance of the protective film-forming film at light (1064 nm), and the transmittance of the protective film-forming film at light (532 nm) and the transmittance of the protective film-forming film at light (1064 nm) obtained above, the absorptance of the protective film-forming film at light (532 nm) and the absorptance of the protective film-forming film at light (1064 nm) were calculated according to the formula (i). The results are shown in Table 3.

[0212] <Evaluation of visibility suppression of protective film-coated chips in light-emitting devices> A silicon wafer with a protective film was obtained in the same manner as in the above-mentioned "measurement of the reflectance of light (420 to 700 nm) of the cured product of the protective film-forming film." A dicing sheet ("Adwill G-562" manufactured by Lintec Corporation) was attached to the exposed surface of the protective film in the obtained silicon wafer with protective film (i.e., the surface opposite to the side on which the silicon wafer was provided), and the silicon wafer was divided (diced) into 2 mm x 2 mm pieces using a dicing blade to produce silicon chips, and the protective film was also cut to the same size. In this way, a large number of silicon chips with protective film, each comprising the silicon chip and the protective film provided on the back surface of the silicon chip after cutting, were produced on the dicing sheet. Next, the resulting silicon chip with the protective film was separated from the dicing sheet and picked up.

[0213] Using the silicon chip with a protective film and measuring 2 mm x 2 mm obtained above, a pseudo-evaluation structure including a light-emitting device was fabricated as shown below. Specifically, a surface-mount white LED package (size: length 3.2 mm × width 2.8 mm × height 2 mm, luminous intensity: 230 mcd (typical)) was mounted on a white substrate (size: 50 mm × 50 mm). The LED package was oriented such that its light emission direction faced away from the white substrate. The minimum reflectance of the white substrate for light in the wavelength range of 420 to 700 nm, measured using the same method as for the cured product of the protective film-forming film described above, was 80%. One protective film-equipped silicon chip was mounted 2 mm from one widthwise end of the LED package, and another protective film-equipped silicon chip was mounted 10 mm from the other widthwise end of the LED package, resulting in a total of two protective film-equipped silicon chips mounted on the white substrate. Each of the two protective film-equipped silicon chips was mounted on the white substrate with its silicon chip facing the white substrate and its protective film facing away from the white substrate. A 15 mm high white resin housing (size: 40 mm x 40 mm) was placed 20 mm away from the center of the LED package in four directions, including the length and width directions of the LED package, and a light diffusion plate (size: 45 mm x 45 mm) with a haze of 50% was placed on top of it to create a pseudo-evaluation structure including a light-emitting device.

[0214] The assembly was then placed in a darkroom, and the LED package was lit at a current of 20 mA. The light-emitting device in this state was visually observed from a position 70 cm directly above it. If neither of the protective film-coated silicon chips was visible, the light-emitting device in the lit state was visually observed from a position 40 cm directly above it. If at least one protective film-coated silicon chip was visible from a position 70 cm above it, visual observation from a position 40 cm above it was not performed. The visibility of the protective film-coated chips in the light-emitting device was evaluated according to the following criteria. The results are shown in Table 3. [Evaluation criteria] A: Two protective silicon chips were not visible from both the 70cm and 40cm positions. B: Two silicon chips with protective film were not visible from the 70 cm position, but one or two silicon chips with protective film were visible from the 40 cm position. C: Only one silicon chip with a protective film was visible from a position of 70 cm. D: Two protective silicon chips were visible from a distance of 70 cm.

[0215] <Evaluation of visibility of laser (532 nm) marking when directly printed on the protective film under laser marking condition (1)> A silicon wafer with a protective film was obtained in the same manner as in the above-mentioned "measurement of the reflectance of light (420 to 700 nm) of the cured product of the protective film-forming film." The obtained silicon wafer with the protective film was allowed to cool to a temperature of 23°C, and then laser marking was performed on the exposed surface of the protective film (the surface opposite to the silicon wafer) using a green laser marker ("CSM300M" manufactured by EO Tech) under the following laser marking conditions (1). [Laser printing conditions (1)] Laser light wavelength: 532nm Printed characters: ABCDEFGHI Printed character size: height 200μm x width 200μm Printed character line width: 20 μm Laser marking speed: 100mm / s Laser frequency: 20kHz Laser power: 0.3W

[0216] The print on the formed protective film was visually observed by five observers at a visibility distance (the distance from the printed protective film to the observer's eye) of 15 cm, and the print visibility when directly printed on the protective film under laser printing condition (1) was evaluated according to the following criteria. The results are shown in the "Direct printing" column under "Laser printing condition (1): Laser (532 nm) print visibility" in Table 3. [Evaluation criteria] A: All five observers were able to see all the printed characters, and the visibility of the printed characters was particularly excellent. B: Four out of five observers were able to see all the printed characters, and the visibility of the printed characters was good. C: The evaluation result does not correspond to either A or B, and the visibility of the print is poor.

[0217] <Evaluation of visibility of laser (532 nm) marking when directly marking on the protective film under laser marking condition (2)> A silicon wafer with a protective film was obtained in the same manner as in the above-mentioned "Measurement of the reflectance of light (420 to 700 nm) of the cured product of the protective film-forming film." Using this silicon wafer with a protective film, direct printing was performed on the protective film in the same manner as in the above-mentioned laser printing condition (1), except that the laser printing conditions were changed to the following laser printing condition (2) instead of the above-mentioned laser printing condition (1). [Laser printing conditions (2)] Laser light wavelength: 532nm Printed characters: ABCDEFGHI Printed character size: Height 75 μm x Width 50 μm Printed character line width: 20 μm Laser marking speed: 100mm / s Laser frequency: 20kHz Laser power: 0.3W

[0218] Using an optical microscope (Keyence Corporation, "Digital Microscope VHX-7000"), one observer observed the print on the protective film formed above under the following conditions: white balance R = 1.77, G = 1.00, B = 2.31, ring illumination, brightness 100, magnification 100x, and shutter speed 1 / 120 sec. The print visibility when directly printed on the protective film under laser printing condition (2) was then evaluated according to the following criteria. The results are shown in the "Direct Printing" column under "Laser Printing Condition (2): Laser (532 nm) Print Visibility" in Table 3. A: The printing is clear and all printed characters (A to I) are visible. B: The printing is generally clear, but is partially unclear, and 7 to 8 of the 9 printed characters (A to I) are visible. C: The printing is unclear, and three or more of the nine printed characters (A to I) are not visible.

[0219] <Evaluation of visibility of laser (1064 nm) marking when directly printed on the protective film> A silicon wafer with a protective film was obtained in the same manner as in the above-mentioned "measurement of the reflectance of light (420 to 700 nm) of the cured product of the protective film-forming film." The obtained silicon wafer with the protective film was allowed to cool to a temperature of 23°C, and then laser printing was performed on the exposed surface of the protective film (the surface opposite to the silicon wafer) using a fiber laser marker ("LP-V10" manufactured by SUNX Corporation) under the following conditions. [Laser printing conditions] Laser light wavelength: 1064nm Printed characters: ABCDEFGHI Printed character size: Height 200 μm x Width 200 μm (minimum value that can be set) Printed character line width: 10 μm Laser marking speed: 500mm / s Laser power: 15.0 (device setting, no unit) Laser pulse period: 200 μs (laser conversion frequency: 5 kHz) Distance between laser head and sample: 19cm

[0220] The print on the formed protective film was visually observed by five observers at a viewing distance (the distance from the printed protective film to the observer's eye) of 15 cm, and the print visibility when printed directly on the protective film was evaluated according to the following criteria. The results are shown in the "Direct Printing" column under "Laser (1064 nm) Print Visibility" in Table 3. [Evaluation criteria] A: All five observers were able to see all the printed characters, and the visibility of the printed characters was particularly excellent. B: Four out of five observers were able to see all the printed characters, and the visibility of the printed characters was good. C: The evaluation result does not correspond to either A or B, and the visibility of the print is poor.

[0221] <<Manufacturing of composite sheets for forming protective films>> <Production of Pressure-Sensitive Adhesive Composition> An acrylic resin (100 parts by mass) was mixed with a crosslinker (a xylene diisocyanate adduct of trimethylolpropane, "Takenate D110N" manufactured by Mitsui Takeda Chemicals) (20 parts by mass), diluted with methyl ethyl ketone, and stirred at 23°C to produce a pressure-sensitive adhesive composition with a combined concentration of the two components other than methyl ethyl ketone of 25% by mass. The amounts of the two components other than methyl ethyl ketone shown here are the amounts of the target product excluding the solvent. The acrylic resin used here was a (meth)acrylic acid ester copolymer (weight-average molecular weight 600,000) obtained by copolymerizing 2-ethylhexyl acrylate (60 parts by mass), methyl methacrylate (30 parts by mass), and 2-hydroxyethyl acrylate (10 parts by mass).

[0222] <Manufacture of support sheet> A third release film ("SP-PET381031" manufactured by Lintec Corporation, thickness 38 μm) made of polyethylene terephthalate, one side of which had been treated for release by silicone treatment, was used, and the adhesive composition obtained above was applied to the release-treated surface using a knife coater, followed by heating and drying at 100°C for 2 minutes to form a non-energy ray-curable adhesive layer (thickness 5 μm).

[0223] Next, an uncolored polypropylene film (thickness 80 μm, melting point 156°C, surface roughness (Ra) of 0.20 μm on one side (matte side), surface roughness (Ra) of 0.15 μm on the other side (slightly matte side)) was used as the substrate, and the exposed surface of the adhesive layer obtained above (the side opposite the release film side) was attached to the matte side to produce a support sheet with a release film, consisting of the substrate, adhesive layer, and third release film laminated in this order in the thickness direction.

[0224] The third release film was removed from the support sheet with a release film obtained above, to expose one side of the pressure-sensitive adhesive layer (the side opposite to the substrate side). The first release film was removed from the protective film-forming film in the laminated film, and the exposed surface (one side) of the resulting protective film-forming film was attached to the adhesive layer in the support sheet using a roller at room temperature. This resulted in a composite sheet for forming a protective film, which was constructed by laminating the support sheet, protective film-forming film, and second release film in this order in the thickness direction.

[0225] <<Evaluation of protective film forming films>> <Evaluation of visibility of laser (532 nm) printing when printing on a protective film through a support sheet under laser printing condition (1)> One side of the silicon wafer was ground with a #2000 wheel to prepare a silicon wafer (thickness 350 μm) having a ground surface. The second release film was removed from the protective film-forming film in the composite sheet for forming a protective film obtained above, and the exposed surface of the protective film-forming film was attached to the ground surface of the silicon wafer using a roller heated to 70 ° C. at a lamination speed of 0.3 m / min. The silicon wafer with the composite sheet for forming a protective film obtained in this way was heated at 140°C for 2 hours to thermally cure the protective film-forming film into a cured product (forming a protective film), thereby obtaining a silicon wafer with a protective film and a support sheet.

[0226] The resulting silicon wafer with protective film was allowed to cool together with the support sheet to 23°C, after which laser (532 nm) printing was performed on the surface of the protective film facing the support sheet (the surface opposite the silicon wafer) through the support sheet using a green laser marker (EO Tech "CSM300M") under the laser printing conditions (1) described above. The support sheet was then removed from the protective film after printing. The visibility of the print on the formed protective film was evaluated in the same manner as in the case of direct printing described above. The results are shown in the column "Printing through support sheet" under "Laser printing conditions (1): Laser (532 nm) print visibility" in Table 3.

[0227] <Evaluation of laser (532 nm) print visibility when printing on a protective film through a support sheet under laser printing condition (2)> A silicon wafer with a protective film provided with a support sheet was obtained in the same manner as in the evaluation under the above-mentioned laser printing condition (1). Using this silicon wafer with a protective film, printing was performed on the protective film through the support sheet in the same manner as in the case of the above-mentioned laser printing condition (1), except that the laser printing conditions were changed to the above-mentioned laser printing condition (2) instead of the above-mentioned laser printing condition (1). Furthermore, the support sheet was removed from the protective film after printing. The visibility of the print on the formed protective film was evaluated in the same manner as in the case of direct printing described above. The results are shown in the column "Printing through support sheet" under "Laser printing conditions (2): Laser (532 nm) print visibility" in Table 3.

[0228] <Evaluation of laser (1064 nm) print visibility when printing on a protective film through a support sheet> In the same manner as in the evaluation under the above laser printing condition (1), a silicon wafer with a protective film and a support sheet was obtained. The silicon wafer with the protective film and the support sheet was allowed to cool to 23°C, after which laser (1064 nm) printing was performed on the surface of the protective film facing the support sheet (the surface opposite the silicon wafer) through the support sheet using a fiber laser marker (LP-V10 manufactured by SUNX Corporation) under the same printing conditions as when printing directly on the protective film as described above. The support sheet was then removed from the protective film after printing. The visibility of the print on the formed protective film was evaluated in the same manner as in the case of direct printing described above. The results are shown in the column "Printing through support sheet" under "Laser (1064 nm) print visibility" in Table 3.

[0229] <<Production of protective film-forming films and composite sheets for protective film-forming, and evaluation of protective film-forming films>> [Examples 2 to 8, Comparative Examples 1 and 2] A protective film-forming film was produced in the same manner as in Example 1, except that the blending amounts of the components of the protective film-forming composition (III) or the types and blending amounts of the components were changed. The types and contents of the components contained in these protective film-forming films are shown in Tables 1 and 2. In addition, the notation "-" in the column of the components contained in the protective film-forming film means that the protective film-forming film does not contain that component.

[0230] Furthermore, composite sheets for forming a protective film were produced in the same manner as in Example 1, except that these protective film-forming films were used. Using these protective film-forming films themselves or composite sheets for forming a protective film, the protective film-forming films were evaluated in the same manner as in Example 1. The results are shown in Tables 3 and 4.

[0231] [Table 1]

[0232] [Table 2]

[0233] [Table 3]

[0234] [Table 4]

[0235] As is clear from the above results, in Examples 1 to 8, the reflectance of the cured product of the protective film-forming film for light (420 to 700 nm) was 28.5% or more, and the visibility of the protective film-containing chip in the light-emitting device was suppressed satisfactorily. That is, the protective film-forming films of Examples 1 to 8 were able to make the protective film-containing workpiece inconspicuous on the white substrate. Furthermore, in Examples 1 to 8, the light (532 nm) absorptance of the cured product was 7.2% or more, or the light (1064 nm) absorptance of the cured product was 10.7% or more, and at least either the laser (532 nm) print visibility or the laser (1064 nm) print visibility was good regardless of whether the print was direct or through a support sheet. That is, the protective film-forming films of Examples 1 to 8 were capable of applying sufficiently dark print to the protective film. The protective film-forming films of Examples 1 to 8 contained both a white pigment and a light absorbing agent as the colorant (J).

[0236] In particular, in Examples 4 and 6, the absorptance of the cured product for light (532 nm) was 11.4% or more, and the absorptance of the cured product for light (1064 nm) was 13.1% or more, and both the laser (532 nm) print visibility and the laser (1064 nm) print visibility were particularly excellent, regardless of whether the print was direct or through a support sheet. In particular, the protective film-forming film of Example 4 contained only a carbon material as the light absorber, and the content ratio of the carbon material to the total mass of the protective film-forming film was 0.025 mass %.

[0237] In Examples 1 to 8, the difference between the maximum and minimum reflectance values ​​of the cured protective film-forming film for light (420 to 700 nm) was 15.5% or less, and these protective film-forming films had excellent properties for making the workpiece with the protective film less noticeable on a white substrate. The protective film-forming films of Examples 1 to 8 contained a white pigment, and in these protective film-forming films, the content of the white pigment relative to the total mass of the protective film-forming film was 1 mass % or more. Among these, the visibility of the protective film-coated chip in the light-emitting device was particularly excellent in Examples 3 and 5 to 8. In Examples 3 and 5 to 8, the difference between the maximum and minimum reflectance of the cured product for light (420 to 700 nm) was 7.3 to 15.5%.

[0238] In Examples 1 to 8, the maximum value of the transmittance of light (420 to 700 nm) of the cured product of the protective film-forming film was 47.6% or less, but the maximum value was 31.4% or less in Examples 3 to 8. That is, the protective film-forming films of Examples 3 to 8 were capable of forming protective films whose color was less affected by the workpiece processed product, and had more preferable properties.

[0239] In Examples 1 to 8, the maximum and minimum values ​​of the reflectance of the protective film-forming film to light (420 to 700 nm) were approximately equal to the maximum and minimum values ​​of the reflectance of the cured product of the protective film-forming film to light (420 to 700 nm), and the wavelength of the light was the same at that time. In other words, the light reflection characteristics of these protective film-forming films hardly changed before and after curing.

[0240] In Examples 1 to 8, the maximum light transmittance (420 to 700 nm) of the protective film-forming film was approximately equal to the maximum light transmittance (420 to 700 nm) of the cured product of the protective film-forming film. In other words, the light transmittance characteristics of these protective film-forming films were almost unchanged before and after curing.

[0241] In Examples 1 to 8, the color tone of both sides of the protective film-forming film was uniform, and these protective film-forming films were advantageous in that the final printing could be clearly confirmed visually, they were easy to manufacture, and the color tone of all protective film-coated workpieces produced from a single protective film-coated workpiece was uniform.

[0242] In contrast, in Comparative Examples 1 and 2, the reflectance of the cured product of the protective film-forming film for light (420 to 700 nm) was 45.0% or more, and the visibility of the protective film-attached chip in the light-emitting device was good. However, the absorptance of the cured product for light (532 nm) was 1.8% or less, and the absorptance of the cured product for light (1064 nm) was 3.9% or less, and both the laser (532 nm) print visibility and the laser (1064 nm) print visibility were poor, regardless of whether the print was direct or through a support sheet. In other words, the protective film-forming films of Comparative Examples 1 and 2 were unable to print sufficiently dark colors on the protective film. The protective film-forming films of Comparative Examples 1 and 2 contained a white pigment as the colorant (J), but did not contain a light absorbing agent. [Industrial Applicability]

[0243] The present invention can be used as a protective film for protecting a workpiece to be mounted on a circuit board. [Explanation of symbols]

[0244] 13: protective film-forming film; 13a: one side (first side) of the protective film-forming film; 13b: other side (second side) of the protective film-forming film; 151: first release film; 152: second release film

Claims

1. A protective film-forming film for forming a protective film on any part of a workpiece obtained by processing a workpiece, When the protective film-forming film is curable, the reflectance of the cured product of the protective film-forming film over the entire wavelength range of 420 to 700 nm is 22% or more, and the absorptance of the cured product of light having wavelengths of 532 nm and / or 1064 nm is 7% or more, When the protective film-forming film is non-curable, the reflectance of the protective film-forming film for light in the entire wavelength range of 420 to 700 nm is 22% or more, and the absorptance of the protective film for light at either or both wavelengths of 532 nm and 1064 nm is 7% or more.

2. When the protective film-forming film is curable, the transmittance of light in the entire wavelength range of 420 to 700 nm of the cured product of the protective film-forming film is 40% or less, The protective film-forming film according to claim 1, wherein when the protective film-forming film is non-curable, the transmittance of the protective film-forming film for light in the entire wavelength range of 420 to 700 nm is 40% or less.

3. The protective film-forming film according to claim 1 or 2, wherein the protective film-forming film contains a white pigment.

4. When the protective film-forming film is curable, the difference between the maximum value and the minimum value of the reflectance of the cured product of the protective film-forming film in the wavelength range of 420 to 700 nm is 20% or less, When the protective film-forming film is non-curable, the difference between the maximum and minimum values ​​of the reflectance of the protective film-forming film in the wavelength range of 420 to 700 nm is 20% or less. The protective film-forming film according to claim 1 or 2.

5. the protective film-forming film contains a carbon material, The protective film-forming film according to claim 1 or 2, wherein the content of the carbon material in the protective film-forming film is 0.1 mass % or less with respect to the total mass of the protective film-forming film.

6. A method for manufacturing a workpiece with a protective film using the protective film-forming film according to claim 1 or 2, When the protective film-forming film is curable, the cured product of the protective film-forming film is the protective film, and when the protective film-forming film is non-curable, the protective film-forming film after being attached to a workpiece is the protective film, In the manufacturing method, the protective film-forming film is attached to the workpiece, Printing is performed on the protective film-forming film or the protective film after it has been attached to the workpiece, The workpiece is processed after the protective film-forming film is attached, thereby producing the workpiece; Cutting the protective film-forming film or the protective film after it has been attached to the workpiece; If the protective film-forming film is curable, the method for manufacturing a workpiece with a protective film further comprises curing the protective film-forming film after being attached to the workpiece to form the protective film.

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