Protective film forming film and method for manufacturing substrate device

Abstract

The present invention provides a protective film-forming film which is a thermosetting protective film-forming film in which when a protective film, which is a thermally cured product of the protective film-forming film, is heated at 260 DEG C for 5 minutes and the light reflectance of the heated protective film is measured, the light reflectance is 26% or more in the full wavelength range of 400-700 nm.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a protective film-forming film and a substrate device.

[0002] This application claims priority based on Japanese Patent Application No. 2023-165209 filed in Japan on September 27, 2023 and Japanese Patent Application No. 2024-113930 filed in Japan on July 17, 2024, and the contents of which are incorporated herein. Background Art

[0003] Among wafers such as semiconductor wafers and insulator wafers, there are wafers that have a circuit formed on one surface (circuit surface) and have convex electrodes such as bumps on the surface (circuit surface). Such wafers are divided into chips, and the convex electrodes are connected to the connection pads on the circuit substrate, thereby being mounted on the circuit substrate.

[0004] In such a wafer or chip, in order to suppress the occurrence of damage such as cracks, the surface (back surface) opposite to the circuit surface may be protected by a protective film.

[0005] In addition, in the process of manufacturing semiconductor devices, a semiconductor device panel described later is used as a workpiece, and in order to suppress the occurrence of warping or cracks in the panel, a protective film may be used to protect any part of the panel.

[0006] At this time, a protective film forming film for forming a protective film is attached to the surface of the workpiece, such as the back side of the wafer, which is opposite to the surface with the convex electrode. Thereafter, the workpiece is processed to produce a workpiece, and the protective film forming film is solidified as needed, and the protective film forming film or the protective film is cut off to manufacture a workpiece with a protective film, which has a workpiece and a protective film arranged on the surface of the workpiece opposite to the surface with the convex electrode. When the protective film forming film is thermosetting, the protective film forming film is thermally solidified to form a protective film. As an example of a workpiece with a protective film, a semiconductor chip with a protective film having a semiconductor chip and a protective film arranged on the back thereof can be cited. Then, the convex electrode in the workpiece with a protective film is brought into contact with the circuit substrate, and the workpiece with a protective film is heated at a high temperature of about 260°C, thereby melting the convex electrode and connecting the workpiece with a protective film to the circuit substrate. When the convex electrode is a solder ball, the heating process is called a reflow process, a solder melting process, or the like. In summary, the workpiece with the protective film is mounted on the circuit board, and then, through the usual process, a substrate device such as a semiconductor device including the workpiece with the protective film is manufactured.

[0007] However, the protective film-forming film may sometimes have a poor appearance during its use. Therefore, as a protective film-forming film, a protective film-forming film that can suppress such poor appearance has been studied according to its use. For example, when transporting a workpiece with a protective film-forming film (a workpiece having a protective film-forming film), the protective film-forming film is sometimes brought into contact with an adsorption means, thereby fixing and transporting the workpiece with the protective film-forming film by adsorption. At this time, sometimes adsorption marks remain on the protective film-forming film, and when the adsorption marks can be visually recognized, problems with the appearance will be caused. In response to the above-mentioned problem points, a protective film-forming film that can suppress the visual recognition of adsorption marks is disclosed (see patent document 1).

[0008] Prior art literature

[0009] Patent Literature

[0010] Patent Document 1: Japanese Patent Application Publication No. 2021-158181 Summary of the invention

[0011] 1. Technical issues to be resolved

[0012] On the other hand, the circuit substrates used in light-emitting devices such as LEDs (light-emitting diodes) are mostly white and other colors with high light reflectivity. At this time, since the protective film in the workpiece with a protective film faces the same direction as the surface of the circuit substrate, it is expected that the presence of the protective film is not conspicuous on the circuit substrate, and its light reflectivity is as high as that of the circuit substrate to improve the design. However, in the heating process of melting the above-mentioned convex electrodes, the protective film will change color, and sometimes the design of the device will be impaired. In this regard, the purpose of the protective film forming film disclosed in Patent Document 1 is not to solve the above-mentioned problem points.

[0013] An object of the present invention is to provide a protective film forming film, which is used to form a protective film with high light reflectivity in a workpiece having a workpiece and a protective film arranged on the workpiece, and can suppress damage to the design of the device even when the protective film is heated at a high temperature of about 260°C.

[0014] (II) Technical solution

[0015] In order to solve the above-mentioned technical problems, the present invention adopts the following structure.

[0016] (1) A protective film-forming film, which is a thermosetting protective film-forming film, wherein when the protective film, which is a thermosetting product of the protective film-forming film, is heated at 260° C. for 5 minutes and the light reflectivity of the heated protective film is measured, the light reflectivity is 26% or more in the entire wavelength region of 400 to 700 nm.

[0017] (2) The protective film-forming film according to (1), wherein the protective film-forming film contains a white pigment.

[0018] (3) A protective film forming film according to (1) or (2), wherein the protective film forming film is used to form a protective film at any position of a workpiece processed by processing the workpiece, and the workpiece processed with a protective film comprising the workpiece processed and the protective film arranged at any position of the workpiece processed is used to be installed on a circuit substrate, and the circuit substrate has a light reflectivity of not less than 30% in the full wavelength region of 400~700nm.

[0019] (4) The protective film-forming film according to any one of (1) to (3), wherein the content of the imidazole-based curing accelerator in the protective film-forming film is less than 0.3% by mass based on the total mass of the protective film-forming film.

[0020] (5) The protective film-forming film according to any one of (1) to (4), wherein the protective film-forming film contains a thermal base generator.

[0021] (6) The protective film-forming film according to any one of (1) to (5), wherein the light reflectance RL(x) of the protective film after heating at 200° C. for 5 minutes is measured at a wavelength interval of 1 nm in the entire wavelength range of 400 to 700 nm, and the light reflectance RH(x) of the protective film after heating at 260° C. for 5 minutes is measured at a wavelength interval of 1 nm in the entire wavelength range of 400 to 700 nm, and when the change rate of the light reflectance at each wavelength is calculated by the following formula based on the RL(x) and RH(x) at the same wavelength, the maximum value of all the absolute values ​​of the change rates is 18% or less:

[0022] The change rate of light reflectivity (%) = ((RL(x)-RH(x)) / RL(x)×100).

[0023] (7) A protective film forming film according to any one of (1) to (6), wherein, for the protective film after heating at 260°C for 5 minutes, when the light reflectance RH(x) is measured at a wavelength interval of 1 nm in the full wavelength range of 400 to 700 nm, the difference between the maximum value RH(x)max of the light reflectance RH(x) and the minimum value RH(x)min of the light reflectance RH(x) is less than 13%.

[0024] (8) A method for manufacturing a substrate device, which is a method for manufacturing a substrate device using a protective film-forming film or a composite sheet for protective film formation, wherein the protective film-forming film is the protective film-forming film described in any one of (1) to (7), and the composite sheet for protective film formation is composed of a support sheet and the protective film-forming film described in any one of (1) to (7) arranged on one surface of the support sheet, and the manufacturing method comprises: an attaching step, wherein the protective film-forming film or the composite sheet for protective film formation that does not constitute the composite sheet for protective film formation is attached to the substrate device. The protective film-forming film in the sheet is attached to the surface of the workpiece that is opposite to the surface having the convex electrode; a thermal curing step, wherein, after the attaching step, the protective film-forming film is thermally cured to form a protective film; a processing and cutting step, wherein, after the attaching step, when the protective film-forming film that does not constitute the composite sheet for protective film formation is used, a processing sheet is attached to the protective film-forming film or the surface of the protective film that is opposite to one side of the workpiece, and the workpiece is processed on the processing sheet to produce a workpiece processed object, and the protective film-forming film is cut. The invention relates to a composite sheet for forming a protective film, wherein the workpiece is processed on the support sheet to produce a workpiece, and the protective film-forming film or the protective film is cut to produce a workpiece processed with a protective film-forming film or a workpiece processed with a protective film, wherein the workpiece processed with the protective film-forming film comprises the workpiece processed with the protective film-forming film and the surface of the workpiece processed with the convex electrode being opposite to the surface of the workpiece processed with the convex electrode. The workpiece processed with the protective film comprises the workpiece processed with the protective film-forming film and the surface of the workpiece processed with the convex electrode being opposite to the surface of the workpiece processed with the convex electrode. The protective film is cut off from the surface of the object which is opposite to the surface having the convex electrode; a picking process, wherein, after the processing and cutting processes, the workpiece with the protective film forming film or the workpiece with the protective film is separated from the processing sheet or the supporting sheet and picked up; and an installation process, wherein, after the picking process and the thermal curing process, the convex electrode in the workpiece with the protective film is brought into contact with a circuit substrate, and then the workpiece with the protective film is heated, thereby melting the convex electrode and connecting it to the circuit substrate.

[0025] (III) Beneficial effects

[0026] According to the present invention, a protective film forming film can be provided, which is used to form a protective film with high light reflectivity in a workpiece processing object having a workpiece processing object and a protective film arranged on the workpiece processing object, and can suppress damage to the design of the device even when the protective film is heated at a high temperature of about 260°C. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1It is a cross-sectional view schematically showing an example of a protective film-forming film according to an embodiment of the present invention.

[0028] Figure 2 This is a cross-sectional view schematically showing an example of a composite sheet for forming a protective film including a protective film-forming film according to an embodiment of the present invention.

[0029] Figure 3A This is a cross-sectional view schematically illustrating an example of a method for manufacturing a substrate device according to an embodiment of the present invention.

[0030] Figure 3B This is a cross-sectional view schematically illustrating an example of a method for manufacturing a substrate device according to an embodiment of the present invention.

[0031] Figure 3C This is a cross-sectional view schematically illustrating an example of a method for manufacturing a substrate device according to an embodiment of the present invention.

[0032] Figure 3D This is a cross-sectional view schematically illustrating an example of a method for manufacturing a substrate device according to an embodiment of the present invention.

[0033] Figure 3E This is a cross-sectional view schematically illustrating an example of a method for manufacturing a substrate device according to an embodiment of the present invention.

[0034] Figure 4A This is a cross-sectional view schematically illustrating another example of the method for manufacturing a substrate device according to one embodiment of the present invention.

[0035] Figure 4B This is a cross-sectional view schematically illustrating another example of the method for manufacturing a substrate device according to one embodiment of the present invention.

[0036] Figure 4C This is a cross-sectional view schematically illustrating another example of the method for manufacturing a substrate device according to one embodiment of the present invention.

[0037] Figure 4D This is a cross-sectional view schematically illustrating another example of the method for manufacturing a substrate device according to one embodiment of the present invention.

[0038] Figure 4E This is a cross-sectional view schematically illustrating another example of the method for manufacturing a substrate device according to one embodiment of the present invention.

[0039] Figure 4FThis is a cross-sectional view schematically illustrating another example of the method for manufacturing a substrate device according to one embodiment of the present invention.

[0040] Description of Reference Numerals

[0041] 101: a composite sheet for forming a protective film; 10: a supporting sheet; 10a: one side (first side) of a supporting sheet; 11: a substrate; 12: an adhesive layer; 13: a protective film-forming film; 13a: one side (first side) of a protective film-forming film; 13b: the side (second side) of the protective film-forming film opposite to the semiconductor wafer side; 13': a protective film; 130': a protective film after cutting (protective film); 6: a circuit substrate; 80: a processing sheet; 9: a semiconductor wafer; 9b: the side (back side) of a semiconductor wafer opposite to the side having convex electrodes; 90: a semiconductor chip; 90a: the side (circuit side) of a semiconductor chip having convex electrodes; 90b: the side (back side) of a semiconductor chip opposite to the side having convex electrodes; 91: a semiconductor chip with a protective film. DETAILED DESCRIPTION

[0042] ◇Protective film forming film

[0043] The protective film-forming film of one embodiment of the present invention is thermosetting. When the protective film as a thermosetting product of the protective film-forming film is heated at 260° C. for 5 minutes and the light reflectivity of the heated protective film is measured, the light reflectivity is 26% or more in the full wavelength region of 400 to 700 nm.

[0044] As described later, the protective film-forming film of the present embodiment can constitute a composite sheet for protective film formation by being laminated with a supporting sheet, for example.

[0045] The protective film-forming film of the present embodiment can be used to form a protective film at any position of a workpiece to be processed, and to protect the workpiece to be processed.

[0046] The protective film-forming film of the present embodiment is soft and can be attached to a workpiece before being processed into a workpiece object.

[0047] That is, by using the protective film-forming film of the present embodiment or the protective film-forming composite sheet having the protective film-forming film, a workpiece with a protective film having a workpiece and a protective film provided at any position of the workpiece can be manufactured. Furthermore, by using the protective film-forming film before manufacturing the workpiece with a protective film, a workpiece with a protective film-forming film having a workpiece and a protective film-forming film provided at any position of the workpiece can be manufactured.

[0048] In this embodiment, the workpiece processed object is obtained by processing the workpiece.

[0049] Examples of the workpiece include a wafer and a semiconductor device panel.

[0050] Examples of the wafer include semiconductor wafers made of elemental semiconductors such as silicon, germanium, and selenium, or compound semiconductors such as GaAs, GaP, InP, CdTe, ZnSe, and SiC; and insulator wafers made of insulators such as sapphire and glass.

[0051] For example, when the workpiece is a semiconductor wafer, a semiconductor chip can be cited as the workpiece to be processed.

[0052] A circuit is formed on one surface of these wafers, and in this specification, the surface of the wafer on which the circuit is formed is referred to as the “circuit surface.” Also, the surface of the wafer opposite to the circuit surface is referred to as the “back surface.”

[0053] The wafer is divided into chips by dicing or other means. In this specification, as in the case of a wafer, the surface of the chip on which the circuit is formed is called the "circuit surface", and the surface of the chip opposite to the circuit surface is called the "back surface".

[0054] The circuit surface of the wafer and the circuit surface of the chip are both provided with convex electrodes such as bumps and pillars. The convex electrodes are preferably made of solder.

[0055] The semiconductor device panel is used in the manufacturing process of the semiconductor device. As a specific example, there can be listed: a semiconductor device in a state where one or more electronic components are sealed with a sealing resin, and a semiconductor device panel constructed by planarly arranging a plurality of the above-mentioned semiconductor devices in an area of ​​a circular, rectangular or other shape.

[0056] The workpiece is preferably a chip (such as a semiconductor chip) provided in the substrate device, or a chip in a light-emitting device. Such a chip may include, for example, a WLCSP (wafer-level chip-scale package) for current control.

[0057] The light emitting device may be a device having 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 having a light emitting element, a substrate device having a sub-millimeter light emitting diode (mini LED) element, and a substrate device having a micro light emitting diode (micro LED) element.

[0058] In this specification, a "substrate device" refers to a device that flips a workpiece with a protective film to a connection pad on a circuit substrate using a convex electrode on its circuit surface. In addition, when a semiconductor wafer is used as a workpiece, a semiconductor device having a semiconductor chip with a protective film can be listed as a substrate device.

[0059] The reflectivity of the circuit board in the light-emitting device is high for visible light, and most of them are white. For example, as a typical circuit board, there is a circuit board whose reflectivity of light in the entire wavelength range of 400 to 700 nm is 30% or more.

[0060] In contrast, in the protective film obtained by forming a film using the protective film of the present embodiment, the absorption of visible light is suppressed, and the protective film is preferably white. Therefore, the workpiece with a protective film having such a protective film is not conspicuous on the circuit substrate in the light-emitting device, and the device with the workpiece with a protective film has high design. In addition, the design of the device having the workpiece with a protective film heated at a high temperature of about 260°C is also high. Thus, in this specification, even after the protective film is heated, the effect of maintaining the high design of the device (i.e., the effect of suppressing the damage to the design of the device) is sometimes referred to as a "design maintenance effect".

[0061] On the other hand, the convex electrodes of the workpiece with a protective film having convex electrodes such as bumps are connected to the connection pads on the circuit substrate, so that when mounted on the circuit substrate, the convex electrodes in the workpiece with a protective film are in contact with the circuit substrate, and the workpiece with a protective film is heated at a high temperature of about 260° C. to melt the convex electrodes (for example, a reflow (melting) process), and the workpiece with a protective film is connected to the circuit substrate. In this embodiment, as heating at a high temperature of about 260° C., such heating to melt the convex electrodes can be cited.

[0062] In this specification, a protective film heated at a high temperature of about 260° C. may be referred to as a “heated protective film”.

[0063] That is, the workpiece with a protective film is used to be mounted on a circuit substrate, and when the light reflectivity of the circuit substrate in the full wavelength region of 400 to 700 nm is 30% or more, the protective film-forming film of this embodiment is particularly suitable for manufacturing the workpiece with a protective film. In such applications, the protective film-forming film of this embodiment has a particularly high effect of maintaining the design of the device.

[0064] <<RH(x)min>>

[0065] When the protective film of the thermally cured product of the protective film-forming film of the present embodiment is heated at 260° C. for 5 minutes and the light reflectance of the heated protective film is measured, the light reflectance is 26% or more in the full wavelength region of 400 to 700 nm. In other words, the minimum value of the light reflectance of the heated protective film in the full wavelength region of 400 to 700 nm is 26% or more.

[0066] Therefore, for example, for the protective film heated at 260° C. for 5 minutes, the light reflectance is measured at a wavelength interval of 1 nm in the entire wavelength range of 400 to 700 nm, and the light reflectance at a wavelength of x nm (x is an arbitrary integer between 400 and 700) is defined as the light reflectance RH(x) (sometimes simply referred to as “RH(x)” in this specification), and all light reflectances RH(x) are 26% or more. That is, the minimum value of all light reflectances RH(x) (sometimes referred to as “RH(x)min” in this specification) is 26% or more.

[0067] As described above, the protective film formed of the protective film-forming film of the present embodiment has a high light reflectivity even when heated at a high temperature of about 260°C.

[0068] RH(x)min is preferably 27.5% or more (the light reflectance of the protective film after heating at 260°C for 5 minutes is preferably 27.5% or more in the full wavelength region of 400 to 700 nm), for example, it can be any range of 29% or more and 31% or more. The higher the RH(x)min, the higher the design maintenance effect of the protective film.

[0069] On the other hand, the upper limit of RH(x)min is not particularly limited. For example, a protective film having a RH(x)min of 50% or less (the light reflectance of the protective film after heating at 260°C for 5 minutes is 50% or less in the entire wavelength range of 400 to 700 nm) is more easily achieved.

[0070] In one embodiment, RH(x)min is, for example, any range of 26% to 50%, 27.5 to 50%, 29 to 50%, and 31 to 50%. However, these ranges are only examples of RH(x)min.

[0071] <<ΔRH(x)>>

[0072] The difference between the maximum value of all light reflectances RH(x) (sometimes referred to as "RH(x)max" in this specification) and the minimum value (RH(x)min) of all light reflectances RH(x) (sometimes referred to as "light reflectance difference ΔRH(x)" or simply "ΔRH(x)") in this specification can be, for example, 17% or less, but preferably 13% or less, and can be any range of 12% or less and 11% or less. There is a tendency that the smaller ΔRH(x), the higher the design maintenance effect of the protective film.

[0073] On the other hand, the lower limit of ΔRH(x) is not particularly limited. For example, a protective film-forming film having a ΔRH(x) of 3% or more can be more easily realized.

[0074] In one embodiment, ΔRH(x) may be, for example, in any range of 3-17%, 3-13%, 3-12%, and 3-11%. However, these ranges are only examples of ΔRH(x).

[0075] The curing conditions when the protective film-forming film of the present embodiment is thermally cured to form a protective film are not particularly limited as long as the degree of curing allows the protective film to fully exhibit its function, and may be appropriately selected according to the type of the thermosetting protective film-forming film.

[0076] For example, the heating temperature during thermal curing of the protective film-forming film is preferably 100 to 200° C., more preferably 110 to 170° C., and particularly preferably 120 to 150° C. Furthermore, the heating time during thermal curing is preferably 0.5 to 5 hours, more preferably 0.5 to 4 hours, and particularly preferably 1 to 3 hours.

[0077] The protective film formed by thermal curing is preferably slowly cooled to room temperature. The method of slowly cooling is not particularly limited, and standing cooling may be performed.

[0078] The protective film before heating used for the measurement of the light reflectance is preferably a cured product obtained by heating the protective film-forming film of the present embodiment at 140° C. for 2 hours.

[0079] <<RH(x)max>>

[0080] RH(x)max is not particularly limited, but is preferably a value satisfying the above-mentioned ΔRH(x).

[0081] For example, RH(x)max may be in any range of 55% or less, 50% or less, and 43% or less, may be greater than 39%, or may be in any range of 39-55%, 39-50%, and 39-43%.

[0082] <<|Rate of change of light reflectance|max>>

[0083] The protective film, which is a thermally cured product of the protective film-forming film of the present embodiment, is heated at 200° C. for 5 minutes. The light reflectance of the heated protective film is measured at a wavelength interval of 1 nm in the entire wavelength range of 400 to 700 nm. The light reflectance at a wavelength of x nm (x is an arbitrary integer between 400 and 700) is defined as the light reflectance RL(x) (sometimes simply referred to as “RL(x)” in this specification). When the change rate of the light reflectance at each wavelength is calculated by the following formula, the maximum value of the absolute values ​​of all the change rates (sometimes referred to as “|change rate of light reflectance|max” in this specification) is preferably 18% or less, more preferably 15% or less, and for example, can be in any range of 12% or less and 9% or less.

[0084] Change rate of light reflectance (%) = ((RL(x)-RH(x)) / RL(x)×100)

[0085] The smaller the |Rate of Change of Light Reflectance|max is, the more uniform the appearance of the heated protective film can be, even if the protective film has deviations in a high-temperature heating environment. Therefore, for example, when a plurality of workpieces with protective films are heated at a high temperature, even if deviations that may normally occur at the heating temperature occur, the color deviations of the heated protective films in the plurality of workpieces with protective films are suppressed, and it is easy to evenly obtain the effect of maintaining the design of the device.

[0086] |Rate of change of light reflectance|max is 18% or less and has the same meaning as all "rates of change of light reflectance" being -18% to 18%.

[0087] On the other hand, a protective film-forming film having a |rate of change in light reflectivity|max of 0% or more, but having a |rate of change in light reflectivity|max of 4% or more is easier to realize, for example.

[0088] In one embodiment, the |change rate of light reflectivity|max may be any range of 4-18%, 4-15%, 4-12% and 4-9%, for example. However, these ranges are only examples of the |change rate of light reflectivity|max.

[0089] The rate of change (%) of light reflectance is calculated using RL(x) and RH(x) at the same wavelength (same x). In the wavelength region of 400 to 700 nm, 301 combinations of RL(400) and RH(400) to RL(700) and RH(700) are used to calculate the rate of change (%) of 301 light reflectances. Then, all (i.e., 301) |rates of change of light reflectances| are calculated from these 301 rates of change of light reflectances, and the maximum value among them is set as |rate of change of light reflectance|max.

[0090] In this specification, examples of deviations in the protective film under a high-temperature heating environment include: a case where the heating temperature of the protective film varies depending on its position even if the protective film is in the same heating space; a case where the heating temperature of the protective film varies over time even if the fixed position of the protective film in the heating space remains unchanged, etc.

[0091] In the manufacturing process of a substrate device such as a semiconductor device having a workpiece with a protective film, sometimes the convex electrode in the workpiece with a protective film is brought into contact with the circuit substrate, and the workpiece with a protective film is heated at a high temperature of about 260°C, thereby melting the convex electrode and connecting (installing) the workpiece with a protective film to the circuit substrate. When the convex electrode is a solder ball, the heating process is called a reflow process, a solder melting process, etc. In addition, in this heating process, for example, sometimes the circuit substrate having the workpiece with a protective film is placed on a conveyor belt and moved into the interior of a heating furnace, thereby heating the workpiece with a protective film at a high temperature. As a more specific example of the deviation under the above-mentioned heating environment, for example, an example can be cited in which the heating temperature of the workpiece with a protective film varies depending on the configuration position of the workpiece with a protective film on the conveyor belt at that time.

[0092] In addition, in recent years, the connection (installation) position of the workpiece with a protective film relative to the circuit board has the following tendency: not only is it adjusted in two directions in the plane, but it is also adjusted in the height direction, and the connection position is three-dimensionally adjusted and complicated. In this case, it is more likely to produce the above-mentioned deviation in the high temperature heating environment.

[0093] The light reflectivity of the protective film after heating such as RH(x), RL(x) and the light reflectivity of the protective film before heating can be adjusted by, for example, 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 (I) described later, the light reflectivity of the protective film after heating and before heating can be adjusted by adjusting the type and content of the colorant (I) in the protective film-forming film. When the colorant is a pigment, the light reflectivity of the protective film after heating and before heating can also be adjusted according to its particle size. For example, in the protective film-forming film, a colorant with a high degree of whiteness is used as a colorant (I), and its content is increased, thereby increasing the light reflectivity of the protective film after heating and before heating. For example, when the protective film-forming film contains a white pigment, the light reflectivity of the protective film after heating and before heating can be increased more easily.

[0094] That is, the protective film-forming film of the present embodiment preferably contains a white pigment. The details of the white pigment will be described later.

[0095] Furthermore, ΔRH(x) and |the rate of change of light reflectivity|max can be adjusted by using the same method as that used to adjust RH(x), RL(x), and the like.

[0096] For example, by making the protective film-forming film not contain components that are easily discolored by heating (for example, around 200~260°C) (sometimes referred to as "discoloring components" in this specification), or by reducing the content of discoloring components in the protective film-forming film when the protective film-forming film contains discoloring components, the reduction in the light reflectivity of the protective film after heating such as RH(x), RL(x), etc. can be more easily suppressed.

[0097] Examples of the color-changing component include imidazole compounds.

[0098] In this specification, the “imidazole compound” is a concept including imidazole (another name: 1,3-oxadiazole) and its derivatives.

[0099] In the present specification, when a structure in which one or more hydrogen atoms in a certain specific compound are substituted with a group other than a hydrogen atom is assumed, the compound having such a substituted structure is referred to as a "derivative" of the specific compound.

[0100] In the present specification, unless otherwise specifically stated, a "group" includes not only an atomic group composed of a plurality of atoms bonded together but also a single atom.

[0101] Examples of the substituent in the imidazole derivative (a substituent replacing a hydrogen atom in imidazole) include an alkyl group, an aryl group, an aralkyl group, a hydroxyalkyl group, a hydroxyaryl group, and a hydroxyaralkyl group.

[0102] The number of hydrogen atoms substituted with a hydroxy group in the hydroxyalkyl group, hydroxyaryl group and hydroxyaralkyl group is not particularly limited as long as it is equal to or less than the number of hydrogen atoms in the unsubstituted alkyl group, aryl group and aralkyl group, but is preferably 1 to 3.

[0103] It is known that among imidazole compounds, 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole and the like are suitable as curing accelerators, which are components contained in the composition for forming a thermosetting protective film-forming film. That is, the protective film-forming film of the present embodiment and the protective film-forming composition (III) for forming the protective film-forming film described later preferably do not contain an imidazole-based curing accelerator (a curing accelerator formed from an imidazole-based compound), or when containing an imidazole-based curing accelerator, the content thereof is preferably small.

[0104] In the protective film-forming film, the content of the imidazole-based curing accelerator (a curing accelerator of an imidazole-based compound) relative to the total mass of the protective film-forming film is preferably less than 0.3% by mass, for example, it may be in any range of 0.2% by mass or less and 0.1% by mass or less. The lower the ratio, the higher the effect of suppressing the decrease in the light reflectivity of the heated protective film such as RH(x) and RL(x).

[0105] On the other hand, the ratio is 0 mass % or more.

[0106] Regardless of whether the imidazole compound is a curing accelerator, in the protective film-forming film, the ratio of the content of the imidazole compound to the total mass of the protective film-forming film and the ratio of the content of the imidazole curing accelerator in the protective film-forming film to the total mass of the protective film-forming film are preferably in the same numerical range.

[0107] <<Storage modulus E'(23) of protective film>>

[0108] A plurality of protective film-forming films of the present embodiment are stacked in their thickness direction to form a test laminated sheet having a thickness of 185 to 215 μm, and the test laminated sheet is heated at 140° C. for 2 hours to thermally cure all the protective film-forming films constituting the test laminated sheet to form a protective film, and a test piece (thickness 185 to 215 μm) having a width of 4.5 mm and a length greater than 20 mm is cut from the heated (thermally cured) test laminated sheet (thickness 185 to 215 μm), and the test piece is gripped at intervals of 20 mm. The test piece is placed at two positions of the sheet, and the storage modulus E' of the test piece is measured at a frequency of 11 Hz while the temperature of the test piece is raised uniformly from 0°C to 300°C at a rate of 3°C / min. The storage modulus E' (23) of the test piece at a temperature of 23°C can be, for example, 800 MPa or more, preferably 1000 MPa or more, for example, 3000 MPa or more, 5000 MPa or more, 7000 MPa or more, 9000 MPa or more, and 11000 MPa or more. The larger the storage modulus E' (23), the more the protective performance of the protective film on the workpiece can be further improved.

[0109] The upper limit of the storage modulus E'(23) of the test piece (protective film) is not particularly limited. For example, a protective film-forming film having a storage modulus E'(23) of preferably 14000 MPa or less, and more preferably 9000 MPa or less is more easily achievable.

[0110] In one embodiment, the storage modulus E'(23) may be, for example, any range of 800-14000 MPa, 1000-14000 MPa, 3000-14000 MPa, 5000-14000 MPa, 7000-14000 MPa, 9000-14000 MPa, and 11000-14000 MPa, or any range of 800-9000 MPa, 1000-9000 MPa, 3000-9000 MPa, 5000-9000 MPa, and 7000-9000 MPa. However, these ranges are only examples of the storage modulus E'(23).

[0111] The thickness of the test piece is preferably 200 μm. If the thickness of the test piece is about 185 to 215 μm (200 ± 15 μm), the measured value of the storage modulus E'(23) is exactly the same as the measured value of the storage modulus E'(23) when the thickness of the test piece is 200 μm, or has a negligible slight error, even if the thickness is any.

[0112] In this specification, “thickness” refers to the average value of thickness measured at five randomly selected locations on an object, and can be obtained using a constant pressure thickness gauge according to JIS K7130, unless otherwise specified, without limitation to the test piece.

[0113] When measuring the storage modulus E', the test piece is gripped at two locations with a 20 mm interval therebetween, which means that the length of the portion of the test piece for measuring the storage modulus E' is 20 mm.

[0114] The two locations of the test piece can be gripped using, for example, a known gripping means such as a clamp.

[0115] The number of protective film-forming films constituting the test piece is not particularly limited as long as it is 2 or more, and can be arbitrarily selected according to the thickness of each protective film-forming film. For example, by using 5 protective film-forming films with a thickness of 40 μm, the test piece with a thickness of 200 μm can be produced. In addition, by using 8 protective film-forming films with a thickness of 25 μm, the test piece with a thickness of 200 μm can be produced. However, this is only an example, and the number and thickness of the protective film-forming films used are not limited thereto.

[0116] Storage modulus E' (23) The storage modulus E' of the protective film can be adjusted by adjusting the type and content of the components contained in the protective film-forming film. For example, by adjusting the type of the curing accelerator (C) in the protective film-forming film by making the protective film-forming film contain the curing accelerator (C) described later, or by increasing the content of the curing accelerator (C), the storage modulus E' of the protective film can be increased.

[0117] Among the curing accelerators (C), a thermal base generator is particularly advantageous in that it has a high effect of suppressing a decrease in the light reflectance of the heated protective film and can increase the storage elastic modulus E'(23) of the protective film.

[0118] That is, the protective film-forming film of the present embodiment preferably contains a thermal base generating agent.

[0119] <Thermal alkali generator>

[0120] In the present specification, the "thermal base generator" refers to a compound that generates a base by heat and is not a compound of the above-mentioned imidazole-based compound.

[0121] Examples of the thermal base generating agent include ammonium salts and phosphonium salts.

[0122] Examples of the ammonium salt include salts of a base and an acid (which can be considered to be formed by a reaction between a base and an acid), and salts composed of a quaternary ammonium cation (a cation having a structure in which four hydrocarbon groups are bonded to a nitrogen atom) and an anion.

[0123] Examples of the phosphonium salt include salts composed of a phosphonium cation and an anion.

[0124] [Alkali]

[0125] In the thermal base generating agent, examples of the base constituting the ammonium salt include primary amines and derivatives thereof, secondary amines and derivatives thereof, tertiary amines and derivatives thereof, and hydrazine and derivatives thereof.

[0126] Examples of the primary amine include monoalkylamines, monoalkenylamines, monoalkadienylamines, monoarylamines, monoarylalkylamines, polyaminoalkane, and polyaminobenzene derivatives.

[0127] Examples of the derivatives of the primary amine include mono(hydroxyalkyl)amine and monoaminoketone.

[0128] Examples of the monoalkylamine include monoalkylamines having 1 to 8 carbon atoms, wherein one hydrogen atom in ammonia (NH3) is substituted by a linear or branched alkyl group having 1 to 8 carbon atoms, or a cyclic alkyl group having 3 to 8 carbon atoms. More specifically, examples of the monoalkylamine include methylamine, ethylamine, n-propylamine, isopropylamine, n-butylamine, isobutylamine, sec-butylamine, tert-butylamine, octylamine, 2-ethylhexylamine, cyclopropylamine, cyclobutylamine, cyclohexylamine, and cyclooctylamine.

[0129] Examples of the monoalkenylamine include monoalkenylamines having 2 to 8 carbon atoms, wherein one hydrogen atom in ammonia is substituted by a linear or branched alkenyl group having 2 to 8 carbon atoms, or a cyclic alkenyl group having 3 to 8 carbon atoms. More specifically, examples of the monoalkenylamine include vinylamine (also known as ethyleneamine), allylamine (also known as 2-propenylamine), octenylamine, cyclopentenylamine, and cyclohexenylamine.

[0130] Examples of the monoalkadienylamine include monoalkadienylamines having 4 to 8 carbon atoms, wherein one hydrogen atom in ammonia is substituted by a linear or branched alkadienyl group having 4 to 8 carbon atoms, or a cyclic alkadienyl group having 4 to 8 carbon atoms. More specifically, examples of the monoalkadienylamine include butadienylamine, pentadienylamine, hexadienylamine, heptadienylamine, octadienylamine, and cyclohexadienylamine.

[0131] Examples of the monoarylamine include monoarylamines having 6 to 12 carbon atoms, wherein one hydrogen atom in ammonia is substituted with a monocyclic or polycyclic aryl group having 6 to 12 carbon atoms. More specifically, examples of the monoarylamine include aniline (also known as phenylamine), naphthylamine, and toluidine (also known as methylaniline).

[0132] Examples of the monoarylalkylamine include monoarylalkylamines having 7 to 13 carbon atoms, wherein one hydrogen atom in ammonia is substituted with a monocyclic or polycyclic arylalkyl group having 7 to 13 carbon atoms. More specifically, examples of the monoarylalkylamine include benzylamine (also known as benzylamine) and (naphthylmethyl)amine.

[0133] Examples of the polyaminoalkane include polyaminoalkane having 1 to 8 carbon atoms, wherein two or more hydrogen atoms in a linear or branched alkane having 1 to 8 carbon atoms, or a cyclic alkane having 3 to 8 carbon atoms are substituted with amino groups. More specific examples of the polyaminoalkane include ethylenediamine, diethylenetriamine, and the like.

[0134] Examples of the polyaminobenzene derivative include polyaminobenzene derivatives having 6 to 12 carbon atoms and having a structure in which one or more hydrogen atoms (but not hydrogen atoms in the amino group) in a compound corresponding to the aminobenzene derivative are replaced by an amino group. More specifically, examples of the polyaminobenzene derivative include toluenediamine (also known as diaminotoluene).

[0135] Examples of the mono(hydroxyalkyl)amine include mono(hydroxyalkyl)amines having 1 to 8 carbon atoms, wherein one hydrogen atom (but not a hydrogen atom in an amino group) in the mono(hydroxyalkyl)amine having 1 to 8 carbon atoms is replaced by a hydroxyl group. More specific examples of the mono(hydroxyalkyl)amine include ethanolamine and the like.

[0136] Examples of the monoaminoketone include monoaminoketones having 3 to 8 carbon atoms, which have a structure in which two hydrogen atoms (-H, -H) bonded to the same carbon atom in a monoalkylamine having 3 to 8 carbon atoms are replaced by one oxygen atom (=O). More specifically, examples of the monoaminoketone include aminoacetone and the like.

[0137] Examples of the monoalkylamine having 3 to 8 carbon atoms include the monoalkylamine having 3 to 8 carbon atoms among the monoalkylamines described above.

[0138] Examples of the secondary amine include dialkylamines, dienylamines, alkylalkenylamines, dialkadienylamines, dialktrienylamines, alkylalktrienylamines, alkenylalkadienylamines, diarylamines, diaralkylamines, alkylarylamines, alkylaralkylamines, alkenylarylamines, alkenylaralkylamines, arylalkadienylamines, N-alkylaminoalkanes, N,N'-dialkylaminoalkanes, pyrrolidine, pyrrolidine derivatives, piperidine, piperidine derivatives, piperazine, and piperazine derivatives.

[0139] Examples of the pyrrolidine derivative include alkyl pyrrolidines other than 1-alkyl pyrrolidine, such as 2-methyl pyrrolidine and 3-methyl pyrrolidine.

[0140] Examples of the piperidine derivative include alkylpiperidines other than 1-alkylpiperidine, such as 2-methylpiperidine, 3-methylpiperidine, and 4-methylpiperidine.

[0141] Examples of the piperazine derivative include alkylpiperazines such as 2-ethylpiperazine which are neither 1-alkylpiperazine nor 1,4-dialkylpiperazine.

[0142] Examples of the alkyl group, alkenyl group, alkadienyl group, aryl group and aralkyl group in the secondary amine include the same groups as the alkyl group, alkenyl group, alkadienyl group, aryl group and aralkyl group in the primary amine.

[0143] Examples of the alkalitenyl group in the secondary amine include a group having a structure in which one single bond (CC) between carbon atoms in the alkalitenyl group in the primary amine is replaced by a double bond (C=C).

[0144] When the secondary amine has two groups classified as the same type such as two alkyl groups, the two groups may be the same as or different from each other.

[0145] Examples of the tertiary amine include trialkylamines, trialkenylamines, dialkylalkenylamines, alkyldialkenylamines, trialkadienylamines, dialkylalktrienylamines, alkyldialktrienylamines, dienylalkadienylamines, alkenyldialkandienylamines, triarylamines, triaralkylamines, dialkylarylamines, alkyldiarylamines, dialkylaralkylamines, alkyldiaralkylamines, dienylarylamines, alkenyldiarylamines, dienylaralkylamines, alkenyldiaralkylamines, diarylalkadienylamines, aryldialkandienylamines, N,N-dialkylaminoalkanes, N,N,N',N'-tetraalkylaminoalkanes, quinuclidines, pyrrolidine derivatives, piperidine derivatives, piperazine derivatives, and the like.

[0146] Examples of the pyrrolidine derivative include 1-alkylpyrrolidines such as 1-methylpyrrolidine.

[0147] Examples of the piperidine derivative include 1-alkylpiperidines such as 1-methylpiperidine.

[0148] Examples of the piperazine derivatives include 1-alkylpiperazine and 1,4-dialkylpiperazine.

[0149] Examples of the alkyl group, alkenyl group, alkadienyl group, aryl group and aralkyl group in the tertiary amine include the same groups as the alkyl group, alkenyl group, alkadienyl group, aryl group and aralkyl group in the primary amine.

[0150] Examples of the alkalitrienyl group in the tertiary amine include the same groups as those mentioned above for the alkalitrienyl group in the secondary amine.

[0151] When the tertiary amine has a plurality of groups classified as the same type, such as 2 to 3 alkyl groups, the plurality of groups may be all the same, all different, or only partly the same.

[0152] The base constituting the thermal base generator is preferably a primary amine, a derivative of a primary amine, a secondary amine, a derivative of a secondary amine, a tertiary amine or a derivative of a tertiary amine, more preferably a cycloamidine, further preferably 1,8-diazabicyclo[5.4.0]undec-7-ene (also known as 1,8-diazabicyclo[5.4.0]-7-undecene, DBU (registered trademark)), a derivative of 1,8-diazabicyclo[5.4.0]undec-7-ene, 1,5-diazabicyclo[4.3.0]non-5-ene (also known as DBN) or a derivative of 1,5-diazabicyclo[4.3.0]non-5-ene, particularly preferably a derivative of 1,8-diazabicyclo[5.4.0]undec-7-ene or 1,8-diazabicyclo[5.4.0]undec-7-ene.

[0153] [acid]

[0154] In the thermal base generator, the acid constituting the ammonium salt may be any of an organic acid and an inorganic acid.

[0155] Examples of the organic acid include carboxylic acids and their derivatives such as aliphatic carboxylic acids, aliphatic carboxylic acid derivatives, aromatic carboxylic acids, and aromatic carboxylic acid derivatives; sulfonic acids such as aliphatic sulfonic acids and aromatic sulfonic acids; and aromatic hydroxy compounds such as phenol, phenol derivatives, naphthol, and naphthol derivatives.

[0156] In this specification, "aromatic carboxylic acid" is a concept including compounds having a carboxyl group directly bonded to an aromatic cyclic group and compounds having a carboxyl group bonded to an aromatic cyclic group via a group other than the aromatic cyclic group. "Aromatic hydroxy compound" is a compound having a hydroxyl group directly bonded to an aromatic cyclic group.

[0157] The aromatic carboxylic acid may be an aromatic monocarboxylic acid having one carboxyl group, or may be an aromatic polycarboxylic acid having two or more carboxyl groups.

[0158] Examples of the aromatic monocarboxylic acid include aromatic monocarboxylic acids having 6 to 12 carbon atoms in the aromatic cyclic group, such as benzoic acid (also known as benzoic acid), p-benzoic acid (also known as 4-methylbenzoic acid), isobenzoic acid (also known as 3-methylbenzoic acid), o-benzoic acid (also known as 2-methylbenzoic acid), 1-naphthoic acid (also known as 1-naphthoic acid), 2-naphthoic acid (also known as 2-naphthoic acid), and cinnamic acid (also known as 3-phenyl-2-propenoic acid).

[0159] Examples of the aromatic polycarboxylic acid include aromatic polycarboxylic acids having 6 to 12 carbon atoms in the aromatic cyclic group, such as phthalic acid (also known as benzene-1,2-dicarboxylic acid), isophthalic acid (also known as benzene-1,3-dicarboxylic acid), terephthalic acid (also known as benzene-1,4-dicarboxylic acid), 1,4-naphthalene dicarboxylic acid (also known as naphthalene-1,4-dicarboxylic acid), and 2,3-naphthalene dicarboxylic acid (also known as naphthalene-2,3-dicarboxylic acid).

[0160] Examples of the aromatic carboxylic acid derivatives include aromatic hydroxymonocarboxylic acids having 6 to 12 carbon atoms in the aromatic ring group, such as salicylic acid (also known as 2-hydroxybenzoic acid), 6-hydroxy-2-naphthoic acid (also known as 6-hydroxynaphthalene-2-carboxylic acid), 3-hydroxy-2-naphthoic acid (also known as 3-hydroxynaphthalene-2-carboxylic acid), and mandelic acid (also known as 2-hydroxy-2-phenylacetic acid).

[0161] Examples of the aromatic carboxylic acid derivative include aromatic hydroxypolycarboxylic acids having an aromatic ring group with 6 to 12 carbon atoms, such as 3-hydroxy-2,7-naphthalenedicarboxylic acid.

[0162] In this specification, a compound having both a carboxyl group and a hydroxyl group is classified as a carboxylic acid derivative.

[0163] The aliphatic carboxylic acid may be an aliphatic monocarboxylic acid having one carboxyl group, or may be an aliphatic polycarboxylic acid having two or more carboxyl groups.

[0164] The aliphatic carboxylic acid may be any of a saturated aliphatic carboxylic acid and an unsaturated aliphatic carboxylic acid.

[0165] Examples of the aliphatic carboxylic acid include saturated aliphatic monocarboxylic acids such as formic acid, acetic acid, propionic acid, isovaleric acid (also known as isovaleric acid), 2-ethylhexanoic acid, and stearic acid; saturated aliphatic polycarboxylic acids (for example, saturated aliphatic dicarboxylic acids) such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, azelaic acid, suberic acid, and sebacic acid; unsaturated aliphatic monocarboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, palmitoleic acid, oleic acid, linoleic acid, and linolenic acid; and unsaturated aliphatic polycarboxylic acids (for example, unsaturated aliphatic dicarboxylic acids) such as fumaric acid and maleic acid.

[0166] Examples of the aliphatic carboxylic acid derivatives include aliphatic halogenated carboxylic acids such as chloroacetic acid, trichloroacetic acid, fluoroacetic acid, 2-chloropropionic acid, and 3-chloropropionic acid; aliphatic alkoxycarboxylic acids such as methoxyacetic acid; aliphatic aryloxycarboxylic acids such as phenoxyacetic acid; aliphatic cyanocarboxylic acids such as cyanoacetic acid; aliphatic hydroxycarboxylic acids such as glycolic acid, lactic acid, citric acid, and tartaric acid (D-tartaric acid, L-tartaric acid, and meso-tartaric acid); and the like.

[0167] The aromatic sulfonic acid may be an aromatic monosulfonic acid having one sulfonic group (-SO3H) or an aromatic polysulfonic acid having two or more sulfonic groups, and is preferably an aromatic monosulfonic acid.

[0168] Examples of the aromatic sulfonic acid include octylbenzenesulfonic acid, butylbenzenesulfonic acid, toluenesulfonic acid, benzenesulfonic acid, and benzenesulfonic acid, and alkylbenzenesulfonic acid, etc., in which the aromatic cyclic group has 6 to 15 carbon atoms.

[0169] Examples of the aliphatic sulfonic acid include saturated aliphatic monosulfonic acids such as methanesulfonic acid, 1-propanesulfonic acid, 1-pentanesulfonic acid, and 1-octanesulfonic acid.

[0170] Among the aromatic hydroxy compounds, the phenol derivative refers to a compound having a structure in which one or two or more hydrogen atoms in phenol (C6H5OH) are substituted by a group other than a hydrogen atom.

[0171] Among the aromatic hydroxy compounds, naphthol derivatives refer to compounds having 1-naphthol or 2-naphthol (C 10A compound having a structure in which one or more hydrogen atoms in H7OH) are replaced by groups other than hydrogen atoms.

[0172] The aromatic hydroxy compound may be an aromatic monohydroxy compound having one hydroxy group, or may be an aromatic polyhydroxy compound having two or more hydroxy groups.

[0173] Examples of the aromatic monohydroxy compound include phenol, p-cresol (also known as 4-methylphenol), m-cresol (also known as 3-methylphenol), o-cresol (also known as 2-methylphenol), 2,3-xylenol (also known as 2,3-dimethylphenol), 2,4-xylenol (also known as 2,4-dimethylphenol), 2,5-xylenol (also known as 2,5-dimethylphenol), 2,6-xylenol (also known as 2,6-dimethylphenol), 3,4-xylenol (also known as 3,4-dimethylphenol), 3,5-xylenol (also known as 3,5-dimethylphenol), 1-naphthol, 2-naphthol and other aromatic monohydroxy compounds having 6 to 12 carbon atoms in the aromatic ring group (phenol, phenol derivatives, naphthol).

[0174] Examples of the aromatic polyhydroxy compound include aromatic polyhydroxy compounds having 6 to 12 carbon atoms in the aromatic ring group such as catechol (also known as 1,2-dihydroxybenzene), resorcinol (also known as 1,3-benzenediol), and 1,5-dihydroxynaphthalene (also known as 1,5-naphthalenediol) (phenol derivatives, naphthol derivatives).

[0175] Examples of the inorganic acid include hydrogen halides such as hydrogen fluoride, hydrogen chloride, hydrogen bromide, and hydrogen iodide; sulfuric acid; and phosphoric acid.

[0176] The acid constituting the thermal base generator is preferably an organic acid, and more preferably a carboxylic acid, a carboxylic acid derivative or an aromatic hydroxy compound.

[0177] When the acid is an aromatic carboxylic acid or a derivative thereof, the acid is more preferably an aromatic polycarboxylic acid or a derivative thereof, and when the acid is an aliphatic carboxylic acid or a derivative thereof, the acid is more preferably an aliphatic monocarboxylic acid or a derivative thereof.

[0178] When the acid is an aromatic hydroxy compound, the acid is more preferably phenol or a derivative thereof.

[0179] [Combination of base and acid]

[0180] From the perspective of being able to more easily increase the storage modulus E' of the protective film, in the thermal base generating agent, the salt of the base and the acid is preferably a salt of a cyclic amidine and an organic acid, more preferably a salt of DBU (registered trademark) or a derivative thereof and an organic acid, further preferably a salt of DBU (registered trademark) or a derivative thereof and a carboxylic acid, a carboxylic acid derivative or an aromatic hydroxy compound, particularly preferably a salt of DBU (registered trademark) or a derivative thereof and an aromatic carboxylic acid, an aromatic carboxylic acid derivative, an aliphatic carboxylic acid, an aliphatic carboxylic acid derivative, phenol or a phenol derivative, and most preferably a salt of DBU (registered trademark) or a derivative thereof and an aromatic polycarboxylic acid, an aromatic polycarboxylic acid derivative, an aliphatic monocarboxylic acid, an aliphatic monocarboxylic acid derivative, phenol or a phenol derivative.

[0181] [Quaternary ammonium cation]

[0182] In the thermal base generator, examples of the quaternary ammonium cation constituting the ammonium salt include a cation having a structure in which four hydrocarbon groups such as alkyl, aryl or aralkyl groups are bonded to a nitrogen atom (a nitrogen atom required for expressing the characteristics of a base) in the base.

[0183] More specifically, the ammonium cations include, for example, tetraalkylammonium cations, trialkylmonoarylammonium cations, dialkyldiarylammonium cations, monoalkyltriarylammonium cations, tetraarylammonium cations, trialkylmonoaralkylammonium cations, dialkyldiaralkylammonium cations, monoalkyltriaralkylammonium cations, tetraaralkylammonium cations, triaralkylmonoarylammonium cations, diaralkyldiarylammonium cations, monoaralkyltriarylammonium cations, etc., wherein four hydrocarbon groups are bonded to a nitrogen atom. However, these cations are only examples of the ammonium cations.

[0184] [Anions constituting ammonium salts]

[0185] In the thermal base generator, examples of the anion constituting the ammonium salt include anions obtained by dissociation of the acid.

[0186] More specifically, the anions include anions obtained by dissociation of organic acids such as the aliphatic carboxylic acids, aliphatic carboxylic acid derivatives, aromatic carboxylic acids, aromatic carboxylic acid derivatives (i.e., carboxylic acids or their derivatives), aliphatic sulfonic acids, aromatic sulfonic acids (i.e., sulfonic acids), phenol, phenol derivatives, naphthol or naphthol derivatives (i.e., aromatic hydroxy compounds); fluoride ions (F - ), chloride ion (Cl - ), bromide ion (Br - ), iodide ion (I - ) (in this specification, they are sometimes collectively referred to as "halide ions"), sulfate ions (SO4 2-), phosphate ion (PO4 3- ), hydrogen phosphate ion (HPO4 2- ) or dihydrogen phosphate ion (H2PO4 - ) etc. However, these anions are only examples of the anions.

[0187] [Combination of ammonium cation and anion]

[0188] From the perspective of being able to more easily increase the storage modulus E' of the protective film, in the thermal base generator, the salt composed of the quaternary ammonium cation and the anion is preferably a salt composed of an anion obtained by dissociation of the organic ammonium cation and an organic acid or an inorganic acid, more preferably a salt composed of an anion obtained by dissociation of a tetraalkylammonium cation, a trialkylmonoarylammonium cation, a dialkyldiarylammonium cation, a monoalkyltriarylammonium cation or a tetraarylammonium cation and a carboxylic acid or a derivative thereof, further preferably a salt composed of an anion obtained by dissociation of a tetraalkylammonium cation or a trialkylmonoarylammonium cation and an aliphatic carboxylic acid or a derivative thereof, and particularly preferably a salt composed of an anion obtained by dissociation of a tetraalkylammonium cation and an aliphatic monocarboxylic acid or a derivative thereof.

[0189] [Phosphonium cation]

[0190] In the thermal base generator, examples of the phosphonium cation constituting the phosphonium salt include a cation having a structure in which four hydrocarbon groups such as an alkyl group, an aryl group, or an aralkyl group are bonded to a phosphorus atom.

[0191] As the phosphonium cation, more specifically, for example, there can be cited organic phosphonium cations composed of four hydrocarbon groups bonded to a phosphorus atom, such as tetraalkylphosphonium cations, trialkylmonoarylphosphonium cations, dialkyldiarylphosphonium cations, monoalkyltriarylphosphonium cations, tetraarylphosphonium cations, trialkylmonoaralkylphosphonium cations, dialkyldiaralkylphosphonium cations, monoalkyltriaralkylphosphonium cations, tetraaralkylphosphonium cations, triaralkylmonoarylphosphonium cations, diaralkyldiarylphosphonium cations, and monoaralkyltriarylphosphonium cations. However, these cations are only examples of the phosphonium cations.

[0192] [Anions constituting phosphonium salt]

[0193] In the thermal base generator, examples of the anion constituting the phosphonium salt include the same anions as those constituting the above-mentioned ammonium salt.

[0194] [Combination of phosphonium cation and anion]

[0195] From the viewpoint of being able to more easily increase the storage modulus E' of the protective film, in the thermal base generator, the salt composed of the phosphonium cation and the anion is preferably a salt composed of an anion obtained by dissociation of the organic phosphonium cation and an organic acid or an inorganic acid, more preferably a salt composed of an anion or halide ion obtained by dissociation of a trialkylmonoarylammonium cation, a dialkyldiarylammonium cation, a monoalkyltriarylammonium cation, a tetraarylammonium cation, a tetraarylalkylammonium cation, a triarylalkylmonoarylammonium cation, a diarylalkyldiarylammonium cation or a monoarylalkyltriarylammonium cation and a sulfonic acid, further preferably a salt composed of an anion or halide ion obtained by dissociation of a monoalkyltriarylammonium cation, a tetraarylammonium cation or a monoarylalkyltriarylammonium cation and an aliphatic sulfonic acid, and particularly preferably a salt composed of an anion or halide ion obtained by dissociation of a monoalkyltriarylammonium cation or a monoarylalkyltriarylammonium cation and a saturated aliphatic monosulfonic acid.

[0196] <<Color tones of both sides of the protective film forming film>>

[0197] Preferably, the color tone of at least two sides of the protective film forming film of this embodiment is single, and the color tone of the entire protective film forming film may be single. This protective film forming film is advantageous in that the printing can be clearly confirmed by the naked eye in the state of the protective film finally subjected to laser printing. In addition, this protective film forming film is also advantageous in that it is easy to manufacture and the color tone of the workpiece with a protective film made from a piece of workpiece with a protective film forming film is uniform.

[0198] Both surfaces of the protective film-forming film are the same as, for example, the first surface and the second surface described later.

[0199] In addition, the color tone of both surfaces of the protective film-forming film is single means that the entire area of ​​both surfaces of the protective film-forming film has a single color tone (same color).

[0200] In the present specification, the first surface and the second surface of the protective film forming film have a single color tone, which means that, for the first surface of the protective film forming film, the light reflectance is measured at a wavelength interval of 1 nm in the entire wavelength range of 400 to 700 nm, the light reflectance at a wavelength of x nm (x is an arbitrary integer from 400 to 700) is defined as light reflectance R1(x), and the light reflectance of the second surface of the protective film forming film measured in the same manner is defined as light reflectance R2(x), and when the difference in light reflectance at each wavelength is calculated by the following formula, the maximum value of all absolute values ​​of the “difference in light reflectance between the first surface and the second surface” (sometimes referred to as “|difference in light reflectance between the first surface and the second surface|max” in the present specification) is less than 1.5%:

[0201] The difference in light reflectivity between the first surface and the second surface (%) = R1(x)-R2(x).

[0202] The fact that the protective film-forming film as a whole has a single color tone means that the protective film-forming film has a single color tone (same color) not only over the entire regions of both surfaces of the protective film-forming film but also over the entire region inside the protective film-forming film.

[0203] The color tone of the protective film-forming film can be adjusted by adjusting the types and contents of the components contained in the protective film-forming film, for example. In particular, the color tone of the protective film-forming film can be adjusted more easily by adjusting the type and content of the colorant (I) contained in the protective film-forming film.

[0204] 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, the multiple layers may be the same or different from each other, and the combination of the multiple layers is not particularly limited.

[0205] In this specification, not limited to the case of a protective film forming film, "multiple layers may be the same as 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 "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".

[0206] When the protective film forming film is composed of more than two layers, due to the poor adhesion between the layers or the difference in the difficulty of expansion and contraction of the layers, undesirable situations such as warping of the protective film and peeling of the protective film from the back of the chip may occur. Furthermore, by stacking multiple layers, the number of steps in manufacturing the protective film forming film increases, and the manufacturing process becomes complicated. Furthermore, due to the increase in the number of steps, the manufacturing cost of the protective film forming film is likely to increase. From the perspective of suppressing such undesirable situations, it is preferred that the protective film forming film is composed of one layer. In addition, when the protective film forming film is composed of one layer (single layer), the difference in light reflectivity between the first surface and the second surface |max is usually less than 1.5%, and the color tones of both sides of the protective film forming film are single.

[0207] The thickness of the protective film-forming film is preferably less than 50 μm, more preferably less than 45 μm, for example, it can be any range of less than 40 μm and less than 35 μm. By making the thickness of the protective film-forming film less than the upper limit, various devices such as the above-mentioned light-emitting device, which have been mounted with a workpiece with a protective film, can be easily thinned.

[0208] On the other hand, the lower limit of the thickness of the protective film forming film is not particularly limited, but is preferably 10 μm or more, for example, from the viewpoint of further increasing the strength of the protective film.

[0209] In one embodiment, the thickness of the protective film-forming film may be, for example, 10 μm or more and less than 50 μm, 10 to 45 μm, 10 to 40 μm, and 10 to 35 μm. However, these ranges are merely examples of the thickness of the protective film-forming film.

[0210] Here, “the thickness of the protective film-forming film” refers to the thickness of the entire protective film-forming film. For example, the thickness of a protective film-forming film composed of a plurality of layers refers to the total thickness of all layers constituting the protective film-forming film.

[0211] <<Protective film forming composition>>

[0212] The protective film-forming film can be formed using a protective film-forming composition (more specifically, a thermosetting 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 on the surface to be formed and drying it as required. The content ratio of the components that do not vaporize at room temperature in the protective film-forming composition is usually the same as the content ratio of the components in the protective film-forming film.

[0213] In this specification, "normal temperature" means a temperature that is not particularly cooled or heated, that is, a normal temperature, and examples thereof include a temperature of 15 to 25°C.

[0214] The protective film-forming film may or may not have energy ray curability in addition to thermosetting property.

[0215] In this specification, "energy ray" refers to an energy ray having an energy quantum in an electromagnetic wave or a charged particle beam, and examples thereof include ultraviolet rays, radiation, electron beams, etc. Ultraviolet rays can be irradiated by, for example, using a high-pressure mercury lamp, a fusion lamp, a xenon lamp, a black light lamp, or an LED lamp as an ultraviolet source. Electron beams can be irradiated by using an electron beam accelerator, etc.

[0216] In the present 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 by irradiation with energy rays.

[0217] In the protective film-forming film, the total content of one or more components described below in the protective film-forming film does not exceed 100% by mass based on the total mass of the protective film-forming film.

[0218] Similarly, in the protective film forming composition, the total content of one or more components described below in the protective film forming composition does not exceed 100% by mass based on the total mass of the protective film forming composition.

[0219] The coating of the protective film-forming composition can be carried out using a known method, for example, methods using various coaters such as an air knife coater, a blade coater, a rod coater, a gravure coater, a roll coater, a roll knife coater, a curtain coater, a die coater, a knife coater, a screen coater, a Meyer rod coater, and a kiss coater.

[0220] The drying conditions of the protective film-forming composition are not particularly limited. However, when the protective film-forming composition contains a solvent described later, it is preferably dried by heating. In addition, the protective film-forming composition containing a solvent is preferably dried by heating at 70 to 130° C. for 10 seconds to 5 minutes. However, since the protective film-forming composition is thermosetting, it is preferred to heat and dry the protective film-forming composition in a manner that does not thermally cure the composition itself and the thermosetting protective film-forming film formed by the composition.

[0221] Preferred protective film-forming films include, for example, protective film-forming films containing a polymer component (A), a thermosetting component (B), a filler (D) and a colorant (I), and protective film-forming films further containing a curing accelerator (C).

[0222] Hereinafter, the composition of the protective film-forming composition will be described in detail.

[0223] <Protective film forming composition (III)>

[0224] Preferred protective film-forming compositions include, for example, protective film-forming compositions (III) (sometimes simply referred to as "composition (III)" in this specification) containing a polymer component (A), a thermosetting component (B), a filler (D), and a colorant (I). The protective film-forming composition (III) preferably further contains a curing accelerator (C).

[0225] [Polymer component (A)]

[0226] The polymer component (A) is a polymer compound for imparting film-forming properties and flexibility to the protective film-forming film. In the present specification, the polymer compound also includes products of polycondensation reactions.

[0227] The polymer component (A) contained in the composition (III) and the protective film-forming film may be one kind or two or more kinds. When two or more kinds are used, the combination and ratio thereof can be arbitrarily selected.

[0228] Examples of the polymer component (A) include acrylic resins, urethane resins, phenoxy resins, silicone resins, and saturated polyester resins, and acrylic resins are preferred.

[0229] Examples of the acrylic resin in the polymer component (A) include known acrylic polymers.

[0230] The weight average molecular weight (Mw) of the acrylic resin is preferably 10,000 to 2,000,000, and can be, for example, any range of 100,000 to 1,500,000, 150,000 to 1,200,000, and 200,000 to 1,000,000. By making the weight average molecular weight of the acrylic resin greater than or equal to the lower limit, it is easier to increase the storage modulus E' such as the storage modulus E' (23) of the protective film (the test piece). By making the weight average molecular weight of the acrylic resin less than or equal to the upper limit, the protective film-forming film is easier to follow the concave-convex surface of the adherend.

[0231] In this specification, unless otherwise specified, the "weight average molecular weight" refers to a polystyrene-equivalent value measured by gel permeation chromatography (GPC).

[0232] The glass transition temperature (Tg) of the acrylic resin is preferably 0 to 70°C, for example, it can be any range of 0 to 50°C, 0 to 30°C and 0 to 10°C. By making the Tg of the acrylic resin above the lower limit, it is easier to adjust the storage modulus E' such as the storage modulus E' (23) of the protective film (the test piece) to the target value. In addition, the adhesion between the protective film and the support sheet described later is suppressed, and the peelability of the support sheet is appropriately improved. On the other hand, by making the Tg of the acrylic resin below the upper limit, the protective film-forming film is easy to follow the concave and convex surface of the adherend.

[0233] When the acrylic resin has two or more structural units, the glass transition temperature (Tg) of the acrylic resin can be calculated using the Fox equation. As the Tg of the homopolymer of the monomer derived from the structural unit used at this time, the value described in the Polymer Data Handbook, the Adhesion Handbook, or the Polymer Handbook can be used.

[0234] Examples of acrylic resins include polymers of one or more (meth)acrylates; copolymers of two or more monomers selected from the group consisting of (meth)acrylates, (meth)acrylic acid, itaconic acid, vinyl acetate, acrylonitrile, styrene, and N-hydroxymethyl acrylamide; and the like.

[0235] Examples of the (meth)acrylate constituting the acrylic resin include:

[0236] (meth)acrylate alkyl esters whose alkyl group constituting the alkyl ester is a chain structure having 1 to 18 carbon atoms, such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, and n-octyl (meth)acrylate;

[0237] Cycloalkyl (meth)acrylates such as isobornyl (meth)acrylate and dicyclopentyl (meth)acrylate;

[0238] Aralkyl (meth)acrylates such as benzyl (meth)acrylate;

[0239] Cycloalkenyl (meth)acrylates such as dicyclopentenyl (meth)acrylate;

[0240] Cycloalkenyloxyalkyl (meth)acrylates such as dicyclopentenyloxyethyl (meth)acrylate;

[0241] (Meth)acrylimide;

[0242] Glycidyl (meth)acrylates such as glycidyl (meth)acrylate;

[0243] Hydroxyl (meth)acrylates such as hydroxymethyl (meth)acrylate and 2-hydroxyethyl (meth)acrylate;

[0244] (Meth)acrylates containing a substituted amino group such as N-methylaminoethyl (meth)acrylate, and the like.

[0245] Here, the "substituted amino group" refers to a group having a structure in which one or two hydrogen atoms of an amino group are substituted with a group other than hydrogen atoms.

[0246] In this specification, "(meth)acrylic acid" is a concept including both "acrylic acid" and "methacrylic acid." Terms similar to (meth)acrylic acid are also the same.

[0247] The monomers constituting the acrylic resin may be one kind or two or more kinds. When there are two or more kinds, the combination and ratio thereof can be arbitrarily selected.

[0248] The acrylic resin may 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 carboxyl group, an isocyanate group, 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 carboxyl group, an isocyanate group, 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 carboxyl group, an isocyanate group, or may bond to other compounds directly without the crosslinking agent (F).

[0249] In the present invention, as the polymer component (A), instead of using an acrylic resin, a thermoplastic resin other than an acrylic resin (hereinafter, sometimes simply abbreviated as "thermoplastic resin") may be used alone, or an acrylic resin and a thermoplastic resin other than an acrylic resin may be used simultaneously. By using the thermoplastic resin, the peelability of the protective film from the support sheet is improved, or the protective film-forming film is easy to follow the uneven surface of the adherend.

[0250] Examples of the thermoplastic resin include polyester, polyurethane, phenoxy resin, polybutene, polybutadiene, and polystyrene.

[0251] The thermoplastic resin contained in the composition (III) and the protective film-forming film may be one kind or two or more kinds. When two or more kinds are used, the combination and ratio thereof may be arbitrarily selected.

[0252] In the composition (III), regardless of the type of the polymer component (A), the content of the polymer component (A) relative to the total content of all components except the solvent is preferably 10 to 85% by mass, for example, it can be any range of 10 to 55% by mass and 10 to 25% by mass, it can also be any range of 40 to 85% by mass and 70 to 85% by mass, and it can also be 40 to 55% by mass.

[0253] This content is synonymous with the following content: regardless of the type of polymer component (A), in the protective film-forming film, the ratio of the content of the polymer component (A) to the total mass of the protective film-forming film is preferably 10~85 mass %, for example, it can be any range of 10~55 mass % and 10~25 mass %, or any range of 40~85 mass % and 70~85 mass %, or 40~55 mass %.

[0254] This is because, in the process of removing the solvent from the resin composition containing the solvent to form a resin film, the amount of components other than the solvent generally does not change, and the content ratio of the components other than the solvent in the resin composition and the resin film is the same. Therefore, in this specification, not limited to the case of forming a protective film, the content of the components other than the solvent is only recorded as the content in the resin film after the solvent is removed from the resin composition.

[0255] The polymer component (A) may also be a thermosetting component (B). In the present invention, when the composition (III) contains a component that is both a polymer component (A) and a thermosetting component (B), the composition (III) is regarded as containing the polymer component (A) and the thermosetting component (B).

[0256] [Thermosetting component (B)]

[0257] The thermosetting component (B) is a component for curing the protective film-forming film.

[0258] The thermosetting component (B) contained in the composition (III) and the protective film-forming film may be one kind or two or more kinds. When two or more kinds are used, the combination and ratio thereof can be arbitrarily selected.

[0259] Examples of the thermosetting component (B) include epoxy-based thermosetting resins, thermosetting polyimide resins, and unsaturated polyester resins, and epoxy-based thermosetting resins are preferred.

[0260] In this specification, the thermosetting polyimide resin is a general term for a polyimide precursor and a thermosetting polyimide which are formed into a polyimide resin by thermal curing.

[0261] (Epoxy thermosetting resin)

[0262] The epoxy-based thermosetting resin is formed of, for example, an epoxy resin (B1) and a thermosetting agent (B2).

[0263] Furthermore, the epoxy-based thermosetting resin may not contain the thermosetting agent (B2) but may be only the epoxy resin (B1).

[0264] The epoxy-based thermosetting resin contained in the composition (III) and the protective film-forming film may be one type or two or more types. When two or more types are used, the combination and ratio thereof can be arbitrarily selected.

[0265] Epoxy resin (B1)

[0266] As the epoxy resin (B1), known epoxy resins can be listed, for example, epoxy compounds having two or more functionalities such as polyfunctional epoxy resins, biphenyl compounds, bisphenol A diglycidyl ether and its hydrogenated product, o-cresol novolac epoxy resin, dicyclopentadiene epoxy resin, biphenyl epoxy resin, bisphenol A epoxy resin, bisphenol F epoxy resin, and phenylene skeleton epoxy resin can be listed.

[0267] As the epoxy resin (B1), an epoxy resin having an unsaturated hydrocarbon group can be used.

[0268] The number average molecular weight of the epoxy resin (B1) is not particularly limited, but is preferably 300 to 30,000 from the viewpoint of the curability of the protective film-forming film and the strength and heat resistance of the protective film.

[0269] The epoxy equivalent of the epoxy resin (B1) is preferably 100 to 1000 g / eq, and may be, for example, in the range of 100 to 600 g / eq or 100 to 300 g / eq.

[0270] The epoxy resin (B1) may be used alone or in combination of two or more. When two or more kinds are used in combination, the combination and ratio thereof may be arbitrarily selected.

[0271] Thermal curing agent (B2)

[0272] The thermosetting agent (B2) functions as a curing agent for the epoxy resin (B1).

[0273] Examples of the thermosetting agent (B2) include compounds having two or more functional groups that can react with an epoxy group in one molecule. Examples of the functional group include phenolic hydroxyl groups, alcoholic hydroxyl groups, amino groups, carboxyl groups, and groups formed by anhydriding an acid group. Phenolic hydroxyl groups, amino groups, or groups formed by anhydriding an acid group are preferred, and phenolic hydroxyl groups or amino groups are more preferred.

[0274] Examples of the phenolic curing agent having a phenolic hydroxyl group in the thermosetting agent (B2) include polyfunctional phenol resins, biphenol, novolac-type phenol resins, dicyclopentadiene-type phenol resins, and aralkyl-type phenol resins.

[0275] Among the thermosetting agents (B2), examples of the amine-based curing agents having an amino group include dicyandiamide and the like.

[0276] The heat curing agent (B2) may have an unsaturated hydrocarbon group.

[0277] In the thermosetting agent (B2), the number average molecular weight of the resin component such as polyfunctional phenol resin, novolac phenol resin, dicyclopentadiene phenol resin, aralkyl phenol resin is preferably 300 to 30,000, for example, 400 to 10,000 and 500 to 3,000.

[0278] In the thermosetting agent (B2), the molecular weight of non-resin components such as biphenol and dicyandiamide is not particularly limited, but is preferably 60 to 500, for example.

[0279] The thermosetting agent (B2) may be used alone or in combination of two or more. When two or more types are used in combination, the combination and ratio thereof may be arbitrarily selected.

[0280] When using a thermosetting agent (B2), in the composition (III) and the protective film forming film, relative to the content of 100 parts by mass of the epoxy resin (B1), the content of the thermosetting agent (B2) is preferably 0.1 to 100 parts by mass, for example, it can be any range 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. By making the content of the thermosetting agent (B2) above the lower limit, it is easier to cure the protective film forming film. By making the content of the thermosetting agent (B2) below the upper limit, the moisture absorption rate of the protective film forming film is reduced, and the reliability of the package obtained by using the protective film forming film is further improved.

[0281] In the protective film-forming film, the content of the thermosetting component (B) relative to the total mass of the protective film-forming film is preferably 5 to 40 mass %, for example, it can be any range of 5 to 30 mass % and 5 to 20 mass %, it can also be any range of 10 to 40 mass % and 13 to 40 mass %, and it can also be 10 to 30 mass %. By making the ratio in such a range, for example, the adhesion between the protective film and the support sheet described later can be appropriately suppressed, and the peelability of the support sheet can be improved.

[0282] Here, when a thermosetting agent (B2) is used, the “content of the thermosetting component (B)” when the thermosetting component (B) is an epoxy thermosetting resin refers to the total content of the epoxy resin (B1) and the thermosetting agent (B2); and when no thermosetting agent (B2) is used, the “content of the thermosetting component (B)” when the thermosetting component (B) is an epoxy thermosetting resin refers to the content of the epoxy resin (B1).

[0283] [Filling material (D)]

[0284] By making the protective film-forming film contain a filler (D), the storage modulus E' of the protective film, such as the storage modulus E' (23), can be more easily adjusted. In addition, by making the protective film-forming film contain a filler (D), it is easy to adjust the thermal expansion coefficient of the protective film-forming film and the protective film, and by optimizing the thermal expansion coefficient of the object to be formed with the protective film, the reliability of the workpiece with the protective film obtained by using the protective film-forming film is further improved. In addition, by making the protective film-forming film contain a filler (D), it is also possible to reduce the moisture absorption rate of the protective film or improve the heat dissipation.

[0285] The filler (D) may be any of an organic filler and an inorganic filler, but is preferably an inorganic filler.

[0286] Preferred inorganic fillers include, for example, powders of silica, alumina, talc, bengala, silicon carbide, boron nitride, etc.; beads obtained by spheroidizing these inorganic fillers; surface-modified products of these inorganic fillers; single crystal fibers of these inorganic fillers; glass fibers, etc.

[0287] Among them, the inorganic filler is preferably silicon dioxide or aluminum oxide, and more preferably silicon dioxide.

[0288] From the viewpoint of improving the dispersibility of the filler (D) in the protective film-forming composition relative to the components other than the filler (D), the silica is preferably silica surface-modified with an organic group (organic compound), more preferably silica surface-modified with a vinyl group, an epoxy group, a phenyl group or a methacryloyl group, and particularly preferably silica surface-modified with a vinyl group or an epoxy group.

[0289] From the viewpoint of improving the dispersibility of the filler (D) in the protective film-forming composition relative to components other than the filler (D), the average particle size of the filler (D) is preferably 0.02 to 2 μm, more preferably 0.05 to 1 μm, and particularly preferably 0.07 to 0.7 μm.

[0290] In this specification, not limited to the case of the filler (D), unless otherwise specified, the "average particle size" refers to the arithmetic mean value of the particle sizes when the particles as the object are observed using an electron microscope, 100 particles are randomly selected, and their particle sizes in the top view are calculated ([the total value of the particle sizes in the top view of the 100 particles] / 100). In addition, as the particle size in this case, the maximum value of the line segment obtained by connecting any two points on the periphery of the particle in the top view can be used.

[0291] For example, for particles in a resin film such as the filler (D) in the protective film-forming film, the resin film is fired to eliminate the resin component, and then the average particle size of the remaining particles can be determined by the above method.

[0292] The filler (D) contained in the composition (III) and the protective film-forming film may be one kind or two or more kinds. When two or more kinds are used, the combination and ratio thereof can be arbitrarily selected.

[0293] In the protective film-forming film, the content of the filler (D) relative to the total mass of the protective film-forming film is preferably 20 to 70 mass %, for example, it may be in any range of 35 to 70 mass % and 50 to 70 mass %, or in any range of 20 to 60 mass % and 20 to 50 mass %, or 35 to 60 mass %. By making the ratio within the above range, it becomes easier to adjust the storage modulus E' such as the storage modulus E' (23) of the protective film.

[0294] [Colorant (I)]

[0295] The light reflectance of the protective film-forming film and the protective film containing the colorant (I) can be easily adjusted.

[0296] Examples of the colorant (I) include known colorants such as inorganic pigments, organic pigments, and organic dyes.

[0297] Examples of the organic pigments and organic dyes include amine pigments, cyanine pigments, merocyanine pigments, croconium pigments, squarylium pigments, azulenium pigments, polymethine pigments, naphthoquinone pigments, pyrylium pigments, phthalocyanine pigments, naphthalocyanine pigments, naphtholactam pigments, azo pigments, condensed coupler pigments, Nitrogen pigments, indigo pigments, perinone pigments, perylene pigments, dioxazine pigments, quinacridone pigments, isoindolinone pigments, quinophthalone pigments, pyrrole pigments, thioindigo pigments, metal complex pigments (metal complex salt dyes), dithiol metal complex pigments, indoxyl pigments, triarylmethane pigments, anthraquinone pigments, naphthol pigments, azomethine pigments, benzimidazolone pigments, pyranthrone pigments and threne pigments.

[0298] Examples of the inorganic pigments include carbon black, cobalt pigments, iron pigments, chromium pigments, titanium pigments, vanadium pigments, zirconium pigments, molybdenum pigments, ruthenium pigments, platinum pigments, ITO (indium tin oxide) pigments, and ATO (antimony tin oxide) pigments.

[0299] The colorant (I) contained in the composition (III) and the protective film-forming film may be one kind or two or more kinds. When two or more kinds are used, the combination and ratio thereof can be arbitrarily selected.

[0300] The colorant (I) is preferably a white pigment, that is, the protective film-forming film preferably contains a white pigment. As described above, when the protective film-forming film contains a white pigment, the light reflectance of the protective film before and after heating can be increased more easily.

[0301] 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 oxide, zinc sulfide, talc, clay, kaolin, titanium phosphate, mica, gypsum, white carbon, diatomaceous earth, bentonite, lithopone, zeolite, sericite, and water halloysite.

[0302] Among them, the white pigment is more preferably titanium oxide.

[0303] When the colorant (I) is 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 viewpoint of improving the dispersibility of the colorant (I) in the protective film-forming composition relative to components other than the colorant (I) and improving the light reflectance of the protective film before and after heating.

[0304] In order to improve the dispersibility of the colorant (I) in components other than the colorant (I), the surface of the colorant (I) may be surface 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. In the colorant (I) subjected to such surface treatment, the site derived from the surface treatment agent is also regarded as a part of the particle, and the particle size of the colorant (I) is defined so as to include the site derived from the surface treatment agent, and the average particle size of the colorant (I) is calculated based on the particle size.

[0305] When the colorant (I) is a white pigment, in the protective film-forming film, the content of the white pigment relative to the total mass of the protective film-forming film is preferably 0.1 to 15 mass %, for example, it can be any range of 0.1 to 10 mass % and 0.1 to 5 mass %, it can also be any range of 3 to 15 mass % and 4 to 15 mass %, and it can also be 3 to 10 mass %. By making the ratio above the lower limit, the effect of using the white pigment, that is, the effect of increasing the light reflectance of the protective film after heating and before heating, becomes higher. By making the ratio below the upper limit, the excessive use of the white pigment can be suppressed.

[0306] When the colorant (I) is a colorant other than a white pigment, in the protective film-forming film, the content of the colorant other than the white pigment relative to the total mass of the protective film-forming film can be, for example, any range of 0.01 to 5 mass%, 0.01 to 1 mass%, and 0.01 to 0.1 mass%. By making the ratio above the lower limit, the protective film-forming film and the protective film can be appropriately colored. By making the ratio below the upper limit, the light reflectance of the protective film after heating and before heating can be more easily increased.

[0307] When the composition (III) and the protective film-forming film contain at least a white pigment as the colorant (I), the content of the white pigment in the composition (III) and the protective film-forming film is preferably 70 to 100% by mass, more preferably 80 to 100% by mass, further preferably 90 to 100% by mass, and particularly preferably 95 to 100% by mass, relative to the total content of the colorant (I) (the total content of the white pigment and the colorants other than the white pigment). By making the ratio equal to or greater than the lower limit, the effect of using the white pigment becomes higher.

[0308] [Curing accelerator (C)]

[0309] The curing accelerator (C) is a component for adjusting the curing speed of the protective film-forming film. Furthermore, by using the curing accelerator (C), the storage modulus E' such as the storage modulus E' (23) of the protective film can be easily increased.

[0310] The curing accelerator (C) is preferably a curing accelerator other than the imidazole curing accelerator. Examples of such a preferred curing accelerator (C) include the thermal base generator and other curing accelerators that are neither the thermal base generator nor the imidazole curing accelerator.

[0311] The thermal alkali generating agent is as described above, and its detailed description is omitted here.

[0312] Examples of the other curing accelerators include tertiary amines such as triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, and tris(dimethylaminomethyl)phenol; and organic phosphines (phosphines in which one or more hydrogen atoms are substituted by organic groups) such as tributylphosphine, diphenylphosphine, and triphenylphosphine.

[0313] The curing accelerator (C) contained in the composition (III) and the protective film-forming film may be one kind or two or more kinds. When two or more kinds are used, the combination and ratio thereof can be arbitrarily selected.

[0314] Among them, when the composition (III) and the protective film-forming film contain a curing accelerator (C), it is preferred that at least the thermal base generator is contained as the curing accelerator (C), and it is particularly preferred that only the thermal base generator is contained as the curing accelerator (C).

[0315] When using a curing accelerator (C), in the composition (III) and the protective film-forming film, the content of the curing accelerator (C) is preferably 1 to 15 parts by mass relative to 100 parts by mass of the content of the thermosetting component (B), for example, it can be any range of 1 to 10 parts by mass and 1 to 5 parts by mass, it can also be any range of 5 to 15 parts by mass and 10 to 15 parts by mass, or it can also be 5 to 10 parts by mass. By making the content of the curing accelerator (C) above the lower limit, the effect of using the curing accelerator (C) can be more significantly obtained. By making the content of the curing accelerator (C) below the upper limit, for example, the effect of suppressing the high-polarity curing accelerator (C) from moving to the bonding interface side with the adherend in the protective film-forming film under high temperature and high humidity conditions and segregating becomes higher. As a result, the reliability of the workpiece processed with the protective film obtained by using the protective film-forming film is further improved.

[0316] When the composition (III) and the protective film-forming film contain at least the thermal base generator as the curing accelerator (C), the content of the thermal base generator in the composition (III) and the protective film-forming film is preferably 70 to 100% by mass, more preferably 80 to 100% by mass, further preferably 90 to 100% by mass, and particularly preferably 95 to 100% by mass relative to the total content of the curing accelerator (C). By making the ratio equal to or greater than the lower limit, the storage modulus E' (23) of the protective film and the like can be easily increased, thereby improving the effect of suppressing the decrease in the light reflectance of the heated protective film.

[0317] [Coupling agent (E)]

[0318] The composition (III) and the protective film-forming film may contain a coupling agent (E). By using a coupling agent having a functional group capable of reacting with an inorganic compound or an organic compound as the coupling agent (E), the adhesion of the protective film to the adherend can be improved. In addition, by using the coupling agent (E), the water resistance of the protective film is improved without compromising the heat resistance.

[0319] The coupling agent (E) is preferably a compound having a functional group that can react with a functional group possessed by the polymer component (A), the thermosetting component (B), etc., and is more preferably a silane coupling agent.

[0320] Preferred silane coupling agents include, for example, 3-glycidyloxypropyl trimethoxysilane, 3-glycidyloxypropyl methyl diethoxysilane, 3-glycidyloxypropyl triethoxysilane, 3-glycidyloxymethyl diethoxysilane, 2-(3,4-epoxycyclohexyl)ethyl trimethoxysilane, 3-methacryloxypropyl trimethoxysilane, 3-aminopropyl trimethoxysilane, 3-(2-aminoethylamino)propyl trimethoxysilane, Methoxysilane, 3-(2-aminoethylamino)propylmethyldiethoxysilane, 3-(phenylamino)propyltrimethoxysilane, 3-anilinopropyltrimethoxysilane, 3-ureapropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, bis(3-triethoxysilylpropyl)tetrasulfide, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriacetoxysilane, imidazolesilane, etc.

[0321] The coupling agent (E) contained in the composition (III) and the protective film-forming film may be one kind or two or more kinds. When two or more kinds are used, the combination and ratio thereof can be arbitrarily selected.

[0322] When a coupling agent (E) is used, in the composition (III) and the protective film-forming film, the content of the coupling agent (E) is preferably 0.03 to 10 parts by mass, for example, 0.03 to 5 parts by mass, 0.03 to 2 parts by mass, and 0.03 to 0.5 parts by mass, relative to 100 parts by mass of the total content of the polymer component (A) and the thermosetting component (B). By making the content of the coupling agent (E) above the lower limit, the effects of using the coupling agent (E), such as improving the dispersibility of the filler (D) in the resin or improving the adhesion between the protective film and the adherend, can be more significantly obtained. By making the content of the coupling agent (E) below the upper limit, the generation of outgassing can be further suppressed.

[0323] [Crosslinking agent (F)]

[0324] When the polymer component (A) is the above-mentioned acrylic resin or the like, and has a functional group such as a vinyl group, a (meth)acryloyl group, an amino group, a hydroxyl group, a carboxyl group, an isocyanate group, etc. that can be bonded to other compounds, the composition (III) and the protective film-forming film may contain a crosslinking agent (F). The crosslinking agent (F) is a component for bonding the functional group in the polymer component (A) to other compounds and crosslinking, and by crosslinking in this way, the adhesion and cohesion of the protective film-forming film can be adjusted.

[0325] Examples of the crosslinking agent (F) include organic polyisocyanate compounds, organic polyimide compounds, metal chelate crosslinking agents (crosslinking agents having a metal chelate structure), and aziridine crosslinking agents (crosslinking agents having an aziridine group).

[0326] The crosslinking agent (F) contained in the composition (III) and the protective film-forming film may be one kind or two or more kinds. When two or more kinds are used, the combination and ratio thereof can be arbitrarily selected.

[0327] When a crosslinking agent (F) is used, the content of the crosslinking agent (F) is preferably 0.01 to 20 parts by mass relative to 100 parts by mass of the content of the polymer component (A) in the composition (III). By making the content of the crosslinking agent (F) above the lower limit, the effect of using the crosslinking agent (F) can be more significantly obtained. By making the content of the crosslinking agent (F) below the upper limit, excessive use of the crosslinking agent (F) can be suppressed.

[0328] [Energy ray curable resin (G)]

[0329] The composition (III) and the protective film-forming film may contain an energy-ray curable resin (G). When the protective film-forming film contains an energy-ray curable resin (G), the properties can be changed by irradiation with energy rays.

[0330] The energy-ray curable resin (G) is an energy-ray curable compound, or an oligomer or polymer (polymer) having energy-ray curability which can be considered to be synthesized from an energy-ray curable compound.

[0331] 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.

[0332] The energy-ray-curable resin (G) contained in the composition (III) and the protective film-forming film may be one kind or two or more kinds. When two or more kinds are used, the combination and ratio thereof can be arbitrarily selected.

[0333] When the energy-ray curable resin (G) is used, the content of the energy-ray curable resin (G) in the composition (III) is preferably 1 to 30% by mass based on the total mass of the composition (III).

[0334] [Photopolymerization initiator (H)]

[0335] When the composition (III) and the protective film-forming film contain the energy-ray curable resin (G), a photopolymerization initiator (H) may be contained in order to efficiently carry out the polymerization reaction of the energy-ray curable resin (G).

[0336] The photopolymerization initiator (H) contained in the composition (III) and the protective film-forming film may be one kind or two or more kinds. When two or more kinds are used, the combination and ratio thereof can be arbitrarily selected.

[0337] When a photopolymerization initiator (H) is used, the content of the photopolymerization initiator (H) is preferably 0.1 to 20 parts by mass based on 100 parts by mass of the energy ray curable resin (G) in the composition (III).

[0338] [General purpose additives (J)]

[0339] The composition (III) and the protective film-forming film may contain a general-purpose additive (J) within a range not impairing the effects of the present invention.

[0340] The general-purpose additive (J) may be a known additive and can be arbitrarily selected according to the purpose without particular limitation. Preferred additives include, for example, a plasticizer, an antistatic agent, an antioxidant, a gettering agent, and an ultraviolet absorber.

[0341] The general-purpose additive (J) contained in the composition (III) and the protective film-forming film may be one kind or two or more kinds. When two or more kinds are used, the combination and ratio thereof can be arbitrarily selected.

[0342] The content of the composition (III) and the general-purpose additive (J) for forming a protective film is not particularly limited and may be appropriately selected depending on the purpose.

[0343] [Solvent]

[0344] The composition (III) preferably further contains a solvent. The composition (III) containing a solvent has good handleability.

[0345] In this specification, unless otherwise specified, the “solvent” is used as a concept including not only a solvent that dissolves a target component but also a dispersion medium that disperses a target component.

[0346] The solvent is not particularly limited, but preferred solvents include, for example, hydrocarbons such as toluene and xylene; alcohols such as methanol, ethanol, 2-propanol, isobutanol (2-methylpropane-1-ol), and 1-butanol; esters such as ethyl acetate; ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran; amides (compounds having an amide bond) such as dimethylformamide and N-methylpyrrolidone, etc.

[0347] The solvent contained in the composition (III) may be only one kind or two or more kinds. When there are two or more kinds, the combination and ratio thereof can be arbitrarily selected.

[0348] The content of the solvent in the composition (III) is not particularly limited and may be appropriately selected according to the types of components other than the solvent, for example.

[0349] <Method for preparing protective film-forming composition (III)>

[0350] The composition (III) can be prepared by blending the respective components for constituting the composition.

[0351] The order of adding the components when blending them is not particularly limited, and two or more components may be added simultaneously.

[0352] When blending, the method for mixing the components is not particularly limited and may be appropriately selected from the following known methods: a method of mixing by rotating a stirring bar or a stirring blade, a method of mixing using a mixer, a method of mixing by applying ultrasonic waves, and the like.

[0353] The temperature and time for adding and mixing the components are not particularly limited as long as the components are not degraded, and may be appropriately adjusted. However, the temperature is preferably 15 to 30°C.

[0354] ◎Example of protective film forming film (1)

[0355] Figure 1 The cross-sectional view schematically shows an example of a protective film forming film according to an embodiment of the present invention. In addition, in order to make it easier to understand the features of the present invention, for convenience, important parts of the figures used in the following description are sometimes enlarged and displayed, and the dimensional ratios of the various components are not necessarily the same as the actual ones.

[0356] The protective film forming film 13 shown here is composed of a first peeling film 151 on one surface (sometimes referred to as the "first surface" in this specification) 13a thereof, and a second peeling film 152 on another surface (sometimes referred to as the "second surface" in this specification) 13b on the opposite side of the first surface 13a.

[0357] Such a protective film-forming film 13 is preferably stored in a roll form, for example.

[0358] The protective film, which is a thermally cured product of the protective film-forming film 13 , was heated at 260° C. for 5 minutes and the light reflectance of the heated protective film was measured. The light reflectance was 26% or more in the entire wavelength region of 400 to 700 nm.

[0359] The protective film-forming film 13 can be formed using the above-mentioned protective film-forming composition.

[0360] Both the first release film 151 and the second release film 152 may be known release films.

[0361] The first release film 151 and the second release film 152 may be identical to each other, or may be different release films having different release forces required when being released from the protective film forming film 13. The first release film 151 and the second release film 152 are preferably release films formed by forming a silicone release agent layer (silicone-treated) on one side of a polyethylene terephthalate film.

[0362] for Figure 1 The protective film forming film 13 shown in the figure has an exposed surface formed by removing any one of the first peeling film 151 and the second peeling film 152, which is a surface to be attached to any position of the workpiece. In addition, the exposed surface formed by removing the remaining other of the first peeling film 151 and the second peeling film 152 is a surface to be attached to a support sheet or a processing sheet described later.

[0363] Although in Figure 1 , an example in which a release film is provided on both sides (the first side 13a and the second side 13b) of the protective film forming film 13 is shown, but the release film may also be provided on only one side of the protective film forming film 13, that is, only on the first side 13a or only on the second side 13b.

[0364] The protective film forming film of this embodiment can be attached to any position of the workpiece (when the workpiece is a semiconductor wafer, it is the back side of the semiconductor wafer) in a manner not to be used simultaneously with the support sheet described later. In this case, a release film can be provided on the surface of the protective film forming film opposite to the surface attached to the workpiece, and the release film can be removed at an appropriate time.

[0365] On the other hand, by using the protective film-forming film of this embodiment together with a support sheet described later, a composite sheet for forming a protective film capable of simultaneously forming and dicing a protective film can be formed. Such a composite sheet for forming a protective film will be described later.

[0366] ◎Example of protective film forming film (2)

[0367] As an example of a preferred protective film-forming film of this embodiment, there can be cited a protective film-forming film which is a thermosetting protective film-forming film.

[0368] The protective film as the thermally cured product of the protective film-forming film is heated at 260° C. for 5 minutes, and the light reflectance of the heated protective film is measured. The light reflectance is 26% or more in the entire wavelength region of 400 to 700 nm.

[0369] The protective film-forming film contains a polymer component (A), an epoxy resin (B1), a thermosetting agent (B2), a filler (D) and a white pigment, and may further contain a curing accelerator (C).

[0370] The curing accelerator (C) is a curing accelerator other than an imidazole-based curing accelerator.

[0371] As an example of a more preferable protective film-forming film of this embodiment, a protective film-forming film which is a thermosetting protective film-forming film can be cited.

[0372] The protective film as the thermally cured product of the protective film-forming film is heated at 260° C. for 5 minutes, and the light reflectance of the heated protective film is measured. The light reflectance is 26% or more in the entire wavelength region of 400 to 700 nm.

[0373] The protective film-forming film contains a polymer component (A), an epoxy resin (B1), a thermosetting agent (B2), a filler (D) and a white pigment, and may further contain a curing accelerator (C).

[0374] The curing accelerator (C) is a curing accelerator other than an imidazole-based curing accelerator.

[0375] In the protective film-forming film, the total content of the epoxy resin (B1) and the thermosetting agent (B2) is 5 to 40% by mass relative to the total mass of the protective film-forming film.

[0376] In the protective film-forming film, the content of the filler (D) is 20 to 70% by mass relative to the total mass of the protective film-forming film.

[0377] In the protective film-forming film, the content of the white pigment is 0.1 to 15% by mass relative to the total mass of the protective film-forming film.

[0378] When the protective film-forming film contains the curing accelerator (C), the content of the curing accelerator (C) is 1 to 15 parts by mass relative to 100 parts by mass of the total content of the epoxy resin (B1) and the thermosetting agent (B2) in the protective film-forming film.

[0379] In the protective film-forming film, the total content of the polymer component (A), epoxy resin (B1), thermosetting agent (B2), filler (D), white pigment and curing accelerator (C) relative to the total mass of the protective film-forming film does not exceed 100 mass %.

[0380] Such a protective film-forming film contains at least a thermal base generator as the curing accelerator (C), and in the protective film-forming film, the content of the thermal base generator is preferably 70 to 100% by mass relative to the total content of the curing accelerator (C).

[0381] ◇Composite sheet for protective film formation

[0382] The protective film-forming composite sheet includes a support sheet and a protective film-forming film provided on one surface of the support sheet, and the protective film-forming film is the protective film-forming film according to one embodiment of the present invention.

[0383] In this specification, the laminated structure of the support sheet and the protective film after the protective film-forming film is cured to become the protective film may be referred to as a "cured composite sheet for protective film formation".

[0384] Hereinafter, each layer constituting the protective film-forming composite sheet will be described in detail.

[0385] ◎Support sheet

[0386] The support sheet may be composed of one layer (single layer) or more than two layers. When the support sheet is composed of multiple layers, the constituent materials and thicknesses of these multiple layers may be the same or different from each other, and the combination of these multiple layers is not particularly limited as long as the effect of the present invention is not impaired.

[0387] The support sheet can be transparent or opaque, and can also be colored according to the purpose.

[0388] For example, when the protective film-forming film has energy ray curability, the support sheet preferably transmits energy rays.

[0389] Examples of the support sheet include a support sheet having a substrate and an adhesive layer provided on one surface of the substrate, a support sheet consisting only of a substrate, etc. When the support sheet has an adhesive layer, in the composite sheet for forming a protective film, the adhesive layer is disposed between the substrate and the protective film-forming film.

[0390] When a support sheet including a substrate and an adhesive layer is used, the adhesion and releasability between the support sheet and the protective film-forming film can be easily adjusted in the composite sheet for forming a protective film.

[0391] When a support sheet consisting only of a base material is used, a composite sheet for forming a protective film can be produced at low cost.

[0392] ◎An example of a composite sheet for forming a protective film

[0393] Figure 2This is a cross-sectional view schematically showing an example of a composite sheet for forming a protective film including a protective film-forming film according to an embodiment of the present invention.

[0394] In addition, Figure 2 In the subsequent drawings, the same components as those shown in the drawings that have already been described are denoted by the same reference numerals as those in the drawings that have already been described, and detailed description thereof will be omitted.

[0395] The protective film forming composite sheet 101 shown here includes a support sheet 10 and a protective film forming film 13 provided on one surface (sometimes referred to as “first surface” in this specification) 10 a of the support sheet 10 .

[0396] The support sheet 10 includes a base material 11 and an adhesive layer 12 provided on one surface 11a of the base material 11. In the composite sheet 101 for forming a protective film, the adhesive layer 12 is arranged between the base material 11 and the protective film-forming film 13.

[0397] That is, the protective film forming composite sheet 101 is configured by laminating the base material 11 , the adhesive layer 12 , and the protective film forming film 13 in this order in the thickness direction thereof.

[0398] The first surface 10 a of the support sheet 10 is identical to a surface 12 a of the adhesive layer 12 that is opposite to the substrate 11 side (sometimes referred to as “first surface” in this specification).

[0399] The protective film forming composite sheet 101 further includes a jig adhesive layer 16 and a release film 15 on the protective film forming film 13 .

[0400] In the composite sheet 101 for forming a protective film, a protective film-forming film 13 is laminated on the entire surface or almost the entire surface of the first surface 12a of the adhesive layer 12, and a jig adhesive layer 16 is laminated on a part of the surface 13a of the protective film-forming film 13 on the side opposite to the adhesive layer 12 (sometimes referred to as the "first surface" in this specification), that is, on the area near the peripheral portion. Furthermore, a release film 15 is laminated on the area of ​​the first surface 13a of the protective film-forming film 13 where the jig adhesive layer 16 is not laminated, and on the surface 16a of the jig adhesive layer 16 on the side opposite to the protective film-forming film 13 (sometimes referred to as the "first surface" in this specification).

[0401] Not limited to the case of the protective film forming composite sheet 101, in the protective film forming composite sheet of the present embodiment, the release film is an arbitrary structure, and the protective film forming composite sheet of the present embodiment may include a release film or may not include a release film.

[0402] The jig adhesive layer 16 is used to fix the protective film-forming composite sheet 101 to a jig such as a ring frame.

[0403] The jig adhesive layer 16 may have, for example, a single-layer structure containing an adhesive component, or a multilayer structure in which layers containing an adhesive component are laminated on both surfaces of a sheet serving as a core material.

[0404] The protective film forming film 13 is one embodiment of the present invention described above. Figure 1 The protective film shown forms a film.

[0405] The composite sheet 101 for forming a protective film is used in the following manner: in a state where the release film 15 is removed, an arbitrary position of the workpiece is attached to the first surface 13a of the protective film forming film 13, and the first surface 16a of the clamp adhesive layer 16 is further attached to a clamp such as a ring frame. When the workpiece is a semiconductor wafer, the back side of the semiconductor wafer is attached to the first surface 13a of the protective film forming film 13.

[0406] The composite sheet for forming a protective film according to the present embodiment is not limited to Figure 2 The protective film forming composite sheet shown in the figure may be changed or deleted without impairing the effect of the present invention. Figure 2 The composite sheet shown may be a composite sheet consisting of a part of the composite sheet for forming a protective film, or may be a composite sheet having another structure added to the composite sheet for forming a protective film described above.

[0407] For example, the composite sheet for forming a protective film of this embodiment may be: Figure 2 In the composite sheet 101 for forming a protective film shown, the size of the protective film forming film 13 in a direction parallel to its first surface 13a is adjusted to be the same as or slightly larger than the size of the workpiece as the object to which the protective film forming film 13 is attached.

[0408] For example, the composite sheet for forming a protective film of this embodiment may also be Figure 2 The composite sheet 101 for forming a protective film shown is a composite sheet for forming a protective film in which the adhesive layer 16 for a jig is not provided.

[0409] For example, the protective film forming composite sheet of this embodiment may also be Figure 2 The support sheet 10 in the protective film forming composite sheet 101 shown is a protective film forming composite sheet in which the support sheet 10 is composed only of a substrate. In this case, it is preferable that at least the surface of the substrate 11 on the protective film forming film 13 side has adhesiveness.

[0410] Next, each layer constituting the support sheet will be described in further detail.

[0411] ○Base material

[0412] The substrate is in a sheet or film shape, and examples of its constituent material include various resins.

[0413] Examples of the resin include polyethylene; polyolefins other than polyethylene such as polypropylene; ethylene-vinyl acetate copolymers and other ethylene copolymers (copolymers obtained using ethylene as a monomer); vinyl chloride resins such as polyvinyl chloride (resins obtained using vinyl chloride as a monomer); polystyrene; polycycloolefins; polyesters such as polyethylene terephthalate; poly(meth)acrylates; polyurethanes; polyurethane acrylates; polyimides; polyamides; polycarbonates; fluororesins; polyacetals; modified polyphenylene ethers; polyphenylene sulfides; polysulfones; polyether ketones, and the like.

[0414] Examples of the resin include polymer alloys such as a mixture of the polyester and other resins.

[0415] Examples of the resin include crosslinked resins obtained by crosslinking one or more of the resins listed above; and modified resins such as ionomers using one or more of the resins listed above.

[0416] The resin constituting the substrate may be only one type or two or more types. When there are two or more types, the combination and ratio thereof can be arbitrarily selected.

[0417] The substrate may consist of one layer (single layer) or two or more layers. When the substrate consists of multiple layers, the multiple layers may be the same as or different from each other, and the combination of the multiple layers is not particularly limited.

[0418] The thickness of the substrate is preferably 50 to 300 μm, for example, 60 to 100 μm. When the thickness of the substrate is within such a range, the flexibility of the composite sheet for forming a protective film and the adhesion suitability to a workpiece are further improved.

[0419] Here, the “thickness of the substrate” refers to the thickness of the entire substrate. For example, the thickness of a substrate composed of a plurality of layers refers to the total thickness of all the layers constituting the substrate.

[0420] The base material may contain various known additives such as a filler, a colorant, an antioxidant, an organic lubricant, a catalyst, a softener (plasticizer), etc. in addition to the above-mentioned main constituent materials such as the resin.

[0421] The substrate may be transparent or opaque, may be colored according to the purpose, and may have other layers deposited thereon.

[0422] In order to adjust the adhesion between the substrate and the layer provided on the substrate (for example, the adhesive layer, the protective film forming film or the other layer), the surface may be subjected to a roughening treatment based on sandblasting, solvent treatment, etc.; an oxidation treatment such as corona discharge treatment, electron beam irradiation treatment, plasma treatment, ozone and ultraviolet irradiation treatment, flame treatment, chromic acid treatment, hot air treatment, etc.; an oleophilic treatment; a hydrophilic treatment, etc. In addition, the surface of the substrate may be subjected to a primer treatment.

[0423] By making the base material contain a component (for example, resin, etc.) within a specific range, at least one surface of the base material can be made to have adhesiveness.

[0424] 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.

[0425] ○Adhesive layer

[0426] The adhesive layer is in a sheet or film shape and contains an adhesive.

[0427] Examples of the adhesive include adhesive resins such as acrylic resins, urethane resins, rubber-based resins, silicone resins, epoxy-based resins, polyvinyl ethers, polycarbonates, and ester-based resins.

[0428] The adhesive layer may consist of one layer (single layer) or two or more layers. When the adhesive layer consists of multiple layers, the multiple layers may be the same or different from each other, and the combination of the multiple layers is not particularly limited.

[0429] The thickness of the adhesive layer is not particularly limited, but is preferably 1 to 100 μm, and may be, for example, in any range of 1 to 60 μm or 1 to 30 μm.

[0430] Here, “the thickness of the adhesive layer” refers to the thickness of the entire adhesive layer. For example, the thickness of an adhesive layer composed of a plurality of layers refers to the total thickness of all the layers constituting the adhesive layer.

[0431] The adhesive layer may be either energy-ray-curable or non-energy-ray-curable. The energy-ray-curable adhesive layer can adjust the physical properties before and after curing.

[0432] The adhesive layer can be formed using an adhesive composition containing an adhesive. For example, the adhesive layer can be formed at the target site by applying the adhesive composition to the target surface of the adhesive layer and drying it as needed. The content ratio of the components that do not vaporize at room temperature in the adhesive composition is usually the same as the content ratio of the components in the adhesive layer.

[0433] The adhesive composition can be applied and dried by, for example, the same method as that for applying and drying the protective film-forming composition.

[0434] The adhesive composition can be obtained by blending the components constituting the adhesive composition, that is, by blending the adhesive and components other than the adhesive as required.

[0435] The adhesive composition can be prepared, for example, by the same method as the protective film forming composition described above, except that the types of the blended components are different.

[0436] ◇Method for producing composite sheet for forming protective film

[0437] The composite sheet for forming a protective film can be produced by stacking the above-mentioned layers so as to have corresponding positional relationships and adjusting the shapes of some or all of the layers as needed. The method for forming each layer is as described above.

[0438] For example, when a pressure-sensitive adhesive layer is laminated on a substrate during production of a support sheet, the pressure-sensitive adhesive composition described above may be applied on the substrate and dried as necessary.

[0439] In addition, the adhesive layer can also be laminated on the substrate by applying the adhesive composition on the release film and drying it as needed to form an adhesive layer on the release film, and laminating the exposed surface of the adhesive layer to one surface of the substrate. In this case, the adhesive composition is preferably applied to the release-treated surface of the release film.

[0440] Although an example of laminating an adhesive layer on a substrate has been described above, the above method can also be applied to, for example, laminating a protective film-forming film or the other layer on a substrate. When laminating a protective film-forming film on a substrate, the protective film-forming composition may be applied to the substrate and dried as required, or the protective film-forming composition may be applied to a release film and dried as required to form a protective film-forming film on the release film, and the exposed surface of the protective film-forming film may be bonded to one surface of the substrate.

[0441] For example, when a protective film-forming film is further laminated on an adhesive layer already laminated on a substrate, a protective film-forming film is first formed on a release film using a protective film-forming composition, and then the exposed surface of the formed protective film-forming film, which is opposite to the side in contact with the release film, is bonded to the exposed surface (first surface) of the adhesive layer.

[0442] Here, an example in which a protective film forming film is laminated on an adhesive layer is described. However, the same method can be adopted also when a layer other than the protective film forming film is laminated on an adhesive layer.

[0443] ◇Method for manufacturing substrate device (method for using protective film forming film)

[0444] The protective film-forming film of the present embodiment can be used for manufacturing a workpiece having a protective film and a substrate device including the workpiece having the protective film.

[0445] A method for manufacturing a substrate device according to an embodiment of the present invention is a method for manufacturing a substrate device using a protective film-forming film or a composite sheet for protective film formation, wherein the protective film-forming film is the protective film-forming film of one embodiment of the present invention described above, and the composite sheet for protective film formation is constituted by having a support sheet and the protective film-forming film arranged on one surface of the support sheet, and the manufacturing method comprises: an attaching step, wherein the protective film-forming film that does not constitute the composite sheet for protective film formation, or the protective film-forming film in the composite sheet for protective film formation is attached to the surface (back side) of the workpiece opposite to the surface (circuit surface) having a convex electrode; a thermal curing step, wherein after the attaching step, the protective film-forming film is thermally cured to form a protective film; a processing and cutting step, wherein after the attaching step, when the protective film-forming film that does not constitute the composite sheet for protective film formation is used, a processing sheet is attached to the surface of the protective film-forming film or the protective film opposite to one side of the workpiece, and the workpiece is processed on the processing sheet to produce a workpiece processed object, and the protective film-forming film is cut off. The invention relates to a composite sheet for forming a protective film, wherein the workpiece is processed on the support sheet to produce a workpiece, and the protective film-forming film or the protective film is cut to produce a workpiece processed with a protective film-forming film or a workpiece processed with a protective film, wherein the workpiece processed with the protective film-forming film comprises the workpiece processed with the protective film-forming film and the surface of the workpiece processed with the convex electrode being opposite to the surface of the workpiece processed with the convex electrode. The workpiece processed with the protective film comprises the workpiece processed with the protective film-forming film and the surface of the workpiece processed with the convex electrode being opposite to the surface of the workpiece processed with the convex electrode. The protective film is cut off from the surface of the object which is opposite to the surface having the convex electrode; a picking process, wherein, after the processing and cutting processes, the workpiece with the protective film forming film or the workpiece with the protective film is separated from the processing sheet or the supporting sheet and picked up; and an installation process, wherein, after the picking process and the thermal curing process, the convex electrode in the workpiece with the protective film is brought into contact with a circuit substrate, and then the workpiece with the protective film is heated, thereby melting the convex electrode and connecting it to the circuit substrate.

[0446] According to the manufacturing method of this embodiment, a workpiece with a protective film is manufactured using the protective film-forming film of this embodiment, and a substrate device having the workpiece with the protective film is further manufactured. In this process, even if the workpiece with the protective film is heated at a high temperature of about 260° C. in the mounting step, the light reflectivity of the heated protective film is high, so it is possible to prevent the design of the device from being damaged.

[0447] As an example of a method for manufacturing a substrate device, i.e., a semiconductor device, when the workpiece is a semiconductor wafer, there can be cited a method for manufacturing a semiconductor device having a semiconductor chip with a protective film, which is a method for manufacturing a semiconductor device having a semiconductor chip with a protective film using a protective film-forming film or a composite sheet for protective film formation, wherein the protective film-forming film is a protective film-forming film of an embodiment of the present invention described above, and the composite sheet for protective film formation is composed of a support sheet and the protective film-forming film arranged on one surface of the support sheet, and the manufacturing method comprises: an attaching step, wherein the protective film is not formed The protective film-forming film of the composite sheet for forming, or the protective film-forming film in the composite sheet for forming a protective film is attached to the surface (back side) of the semiconductor wafer opposite to the surface (circuit side) having a convex electrode; a thermal curing process, wherein, after the attaching process, the protective film-forming film is thermally cured to form a protective film; a processing and cutting process, wherein, after the attaching process, when the protective film-forming film that does not constitute the composite sheet for forming a protective film is used, a processing sheet is attached to the protective film-forming film or the surface of the protective film that is opposite to one side of the semiconductor wafer, and the semiconductor is processed on the processing sheet The semiconductor chip is manufactured by processing the semiconductor wafer on the support sheet, and the protective film forming film or the protective film is cut off. When the composite sheet for forming the protective film is used, the semiconductor chip is manufactured by processing the semiconductor wafer on the support sheet, and the protective film forming film or the protective film is cut off, thereby manufacturing a semiconductor chip with a protective film forming film or a semiconductor chip with a protective film. The semiconductor chip with a protective film forming film comprises the semiconductor chip and the surface (back side) of the semiconductor chip which is opposite to the surface (circuit surface) having the convex electrodes after the protective film forming film is cut off. The semiconductor chip with a protective film comprises the semiconductor chip. The protective film after cutting off the surface (back side) of the semiconductor chip opposite to the surface (circuit surface) having the convex electrode; a picking process, wherein, after the processing and cutting processes, the semiconductor chip with the protective film forming film or the semiconductor chip with the protective film is separated from the processing sheet or the supporting sheet and picked up; and an installation process, wherein, after the picking process and the thermal curing process, the convex electrode in the semiconductor chip with the protective film is brought into contact with the circuit substrate, and then the semiconductor chip with the protective film is heated, thereby melting the convex electrode and connecting it to the circuit substrate.

[0448] When the workpiece is a semiconductor wafer, the order of processing (dividing, singulating) the semiconductor wafer and cutting the protective film forming film or the protective film in the processing and cutting steps can be selected arbitrarily according to the purpose. Cutting can be performed after processing, processing and cutting can be performed at the same time, or processing can be performed after cutting.

[0449] In this embodiment, regardless of the order of processing the semiconductor wafer and forming a protective film or cutting the protective film, if the processing of the semiconductor wafer and the forming of the protective film or cutting of the protective film are performed continuously without interruption through the same operation, the processing and cutting are deemed to be performed simultaneously.

[0450] Processing of the semiconductor wafer (hereinafter, sometimes simply referred to as "processing") and cutting of the protective film forming film or the protective film (hereinafter, sometimes simply referred to as "cutting") can be performed using a known method according to the order of processing and cutting.

[0451] When the semiconductor wafer is cut after being processed, the processing can be performed by, for example, Stealth Dicing (registered trademark) or laser dicing.

[0452] Stealth Dicing (registered trademark) refers to the following method. That is, first, a predetermined division position is set inside the semiconductor wafer, and the position is used as a focus, and a laser is irradiated in a manner focused on the focus, thereby forming a modified layer inside the semiconductor wafer. Unlike other positions of the semiconductor wafer, the modified layer of the semiconductor wafer is modified by irradiating the laser, and its strength becomes weaker. Therefore, by applying force to the semiconductor wafer, cracks extending along the two-sided direction of the semiconductor wafer are generated at the modified layer inside the semiconductor wafer, which becomes the starting point for dividing (processing) the semiconductor wafer. Then, force is applied to the semiconductor wafer to divide the semiconductor wafer at the position of the modified layer to produce semiconductor chips.

[0453] When the protective film forming film or the protective film is cut after processing, the cutting of the protective film forming film or the protective film can be performed, for example, by stretching the protective film forming film or the protective film in a direction parallel to the surface attached to the semiconductor chip, so-called expansion. The expanded protective film forming film or the protective film is cut along the periphery of the semiconductor chip. Cutting based on such expansion is preferably performed at a low temperature such as -20 to 5°C.

[0454] When processing and cutting are performed simultaneously, the semiconductor wafer can be processed and the protective film formed or the protective film can be cut simultaneously by various cutting methods such as blade dicing using a blade, laser cutting based on laser irradiation, or water cutting based on spraying of water containing a polishing agent.

[0455] In addition, a modified layer is formed by stealth dicing (registered trademark), and the semiconductor wafer that has not been divided (processed) and the protective film forming film or protective film are simultaneously expanded using the same method as above, thereby making it possible to simultaneously divide (process) the semiconductor wafer and cut the protective film forming film or protective film.

[0456] When processing is performed after cutting, the protective film forming film or the protective film can be cut without processing the semiconductor wafer by using the same various dicing techniques as described above, and then the semiconductor wafer can be processed (divided) by breaking.

[0457] Hereinafter, a method for manufacturing a substrate device according to the present embodiment will be described by taking a semiconductor wafer as an example of a workpiece and a semiconductor chip as an example of a workpiece to be processed.

[0458] <<Manufacturing method (1)>>

[0459] Figure 3A to Figure 3E The cross-sectional view schematically illustrates an example of a method for manufacturing a substrate device when the workpiece is a semiconductor wafer. Figure 2 A method for producing the composite sheet 101 for forming a protective film will be described below.

[0460] In this specification, a method for manufacturing a substrate device using a composite sheet for forming a protective film may be referred to as "manufacturing method (1)".

[0461] <Attachment process (1)>

[0462] In the attaching step (sometimes referred to as "attaching step (1)" in this specification) of the manufacturing method (1), a protective film-forming composite sheet from which the release film 15 is removed is used as the protective film-forming composite sheet 101, and the protective film-forming film 13 in the protective film-forming composite sheet 101 is attached to the surface (back surface) 9b of the semiconductor wafer 9 opposite to the surface (circuit surface) 9a having the convex electrodes. Figure 3A As shown, a semiconductor wafer 901 with a composite sheet for forming a protective film is manufactured, which is composed of a semiconductor wafer 9 and a composite sheet 101 for forming a protective film provided on the back side 9b of the semiconductor wafer 9. The semiconductor wafer 9 is a workpiece, and the semiconductor wafer 901 with a composite sheet for forming a protective film is a workpiece with a composite sheet for forming a protective film.

[0463] In the attaching step (1), the protective film-forming film 13 may be heated to be softened and attached to the semiconductor wafer 9 .

[0464] Here, in the semiconductor wafer 9, bumps and the like on the circuit surface 9a are omitted from illustration. This also applies to the following figures.

[0465] In order to set the thickness of the semiconductor wafer 9 to a target value, the back surface thereof may be ground. That is, the back surface 9 b of the semiconductor wafer 9 may be a ground surface.

[0466] <Thermal curing process (1)>

[0467] After the attaching step (1) of the manufacturing method (1), in the thermal curing step (sometimes referred to as "thermal curing step (1)" in this specification), the protective film forming film 13 is thermally cured to form a protective film 13'. Figure 3B As shown, a semiconductor wafer 9011 with a composite sheet for forming a cured protective film is manufactured, which is composed of a semiconductor wafer 9 and a composite sheet 1011 for forming a cured protective film provided on the back side 9b of the semiconductor wafer 9. The semiconductor wafer 9011 with a composite sheet for forming a cured protective film is a workpiece with a composite sheet for forming a cured protective film.

[0468] The first surface 13 a ′ of the protective film 13 ′ corresponds to the first surface 13 a of the protective film-forming film 13 , and the second surface 13 b ′ of the protective film 13 ′ corresponds to the second surface 13 b of the protective film-forming film 13 .

[0469] In the thermal curing step (1), the heating temperature and heating time of the protective film-forming film 13 when thermally curing the protective film-forming film 13 are as described above.

[0470] <Processing and cutting process (1)>

[0471] In the manufacturing method (1), after the thermal curing step (1), the semiconductor wafer 9 is processed (divided) on the support sheet 10 to produce the semiconductor chips 90, and the protective film 13' is cut (sometimes referred to as "processing and cutting step (1)" in this specification). Figure 3C As shown, a plurality of semiconductor chips 91 with protective films are manufactured, which are composed of a semiconductor chip 90 and a cut protective film 130' provided on the back side 90b of the semiconductor chip 90. The semiconductor chip 90 is a workpiece, and the semiconductor chip 91 with protective films is a workpiece with protective films. The plurality of semiconductor chips 91 with protective films are arranged and held on a support sheet 10, and the semiconductor chips 91 with protective films and the support sheet 10 constitute a semiconductor chip group 910 with protective films.

[0472] The order of processing the semiconductor wafer 9 and cutting the protective film 13 ′ is as described above and is not limited.

[0473] The method of processing the semiconductor wafer 9 and cutting the protective film 13 ′ is as described above.

[0474] The first surface 130a' of the protective film 130' after cutting corresponds to the first surface 13a' of the protective film 13' before cutting, and the second surface 130b' of the protective film 130' after cutting corresponds to the second surface 13b' of the protective film 13' before cutting.

[0475] In this specification, the "protective film after cutting" may be simply referred to as "protective film".

[0476] The surface (circuit surface) 90 a having the protruding electrodes of the semiconductor chip 90 corresponds to the circuit surface 9 a of the semiconductor wafer 9 .

[0477] <Pick-up process (1)>

[0478] After the thermal curing step (1) and the processing and cutting step (1) of the manufacturing method (1), in the picking-up step (sometimes referred to as "picking-up step (1)" in this specification), Figure 3D As shown, the semiconductor chip 91 with a protective film is separated and picked up from the support sheet 10. In this way, the semiconductor chip 91 with a protective film can be taken out from the semiconductor chip group 910 with a protective film.

[0479] Figure 3D In the figure, the arrow P indicates the picking direction.

[0480] The semiconductor chip 91 with a protective film can be picked up by a known method. For example, as the separating means 7 for separating the semiconductor chip 91 with a protective film from the support sheet 10, a vacuum chuck or the like can be cited.

[0481] <Installation process (1)>

[0482] After the pick-up step (1) and the heat curing step (1) of the manufacturing method (1), in the mounting step (sometimes referred to as "mounting step (1)" in this specification), the convex electrodes (not shown) in the semiconductor chip 91 with the protective film after picking up are brought into contact with the circuit substrate 6, more specifically, with the connection pads (not shown) provided on the circuit surface 6a of the circuit substrate 6, and then the semiconductor chip 91 with the protective film is heated. Figure 3E As shown, the convex electrodes in the semiconductor chip 91 with protective film are melted and electrically connected to the circuit substrate 6, more specifically, the connection pads by soldering. Thus, the semiconductor chip 91 with protective film is flip-chip connected to the connection pads on the circuit substrate 6 with the convex electrodes therein.

[0483] In addition, Figure 3E In the substrate 6, the connection pads and circuits are omitted. Figure 4F Same.

[0484] The flip-chip connection of the semiconductor chip 91 with a protective film to the connection pads on the circuit board 6 can be performed by a known method.

[0485] For example, in order to melt the bump electrodes in the semiconductor chip 91 with the protective film, the temperature at which the semiconductor chip 91 with the protective film is heated is preferably 255 to 265°C.

[0486] By using the protective film forming film 13, the light reflectivity of the protective film after being heated at a high temperature is high, so that the design of the device can be prevented from being damaged. In addition, the circuit substrate 6 includes a plurality of semiconductor chips 91 with protective films. When the circuit substrate 6 is heated at a high temperature, even if there is a deviation that may normally occur at the heating temperature, the color deviation in the heated protective films 130' is suppressed, and it is easy to evenly obtain the design maintenance effect.

[0487] <Other processes (1)>

[0488] The manufacturing method (1) may have other steps that are not included in any of the attaching step (1), the thermal curing step (1), the processing and cutting step (1), the picking up step (1) and the installing step (1) (sometimes referred to as "other steps (1)" in this specification), or may not have other steps that are not included in any of the attaching step (1), the thermal curing step (1), the processing and cutting step (1), the picking up step (1) and the installing step (1).

[0489] The type of other step (1) and the timing of performing the other step (1) can be arbitrarily selected according to the purpose and are not particularly limited.

[0490] [Printing process (1)]

[0491] As another step (1), for example, a protective film is formed on the protective film or the second surface of the protective film (on the Figure 3A~Figure 3B In the printing step (1) (not shown), for example, a second surface 13b of the protective film forming film 13 or a second surface 13b' of the protective film 13' is irradiated with laser to print the protective film forming film or the protective film. Printing is performed on the second surface of the protective film forming film or the protective film.

[0492] In the printing process (1), the second surface of the protective film forming film is irradiated with laser from the outside of the support sheet side of the composite sheet for forming the protective film through the support sheet, or the second surface of the protective film is irradiated with laser from the outside of the support sheet side of the cured composite sheet for forming the protective film through the support sheet.

[0493] The printing step (1) can be performed by a known method.

[0494] In this embodiment, the printing step (1) can be performed after the attaching step (1), and is preferably performed between the thermal curing step (1) and the processing and cutting step (1).

[0495] [Grinding process (1), back grinding tape removal process (1)]

[0496] As another step (1), for example, the following steps can be mentioned: using a semiconductor wafer on the surface (circuit surface) having a protruding electrode (on the Figure 3A In the process, a semiconductor wafer with back grinding tape, for example, formed by attaching back grinding tape to the circuit surface 9a) of the semiconductor wafer 9 is used as a semiconductor wafer, and a grinding process (1) is performed to grind the back side of the semiconductor wafer in the semiconductor wafer with back grinding tape; and after the grinding process (1), a back grinding tape removal process (1) is performed to remove the back grinding tape from the circuit surface of the semiconductor wafer.

[0497] Both the grinding step (1) and the back grinding tape removal step (1) can be performed by a known method.

[0498] The grinding step (1) is performed before the attaching step (1).

[0499] The back grinding tape removal step (1) is preferably performed after the attachment step (1).

[0500] <Timing of performing the thermal curing step (1)>

[0501] So far, the case where the heat curing step (1) is performed between the attaching step (1) and the processing and cutting step (1) has been described. However, in the manufacturing method (1), the timing of performing the heat curing step (1) is not limited to this, and it can be performed after the attaching step (1). For example, the heat curing step (1) can be performed at any timing between the printing step (1) and the processing and cutting step (1), between the processing and cutting step (1) and the picking up step (1), and between the picking up step (1) and the mounting step (1).

[0502] <<Manufacturing method (2)>>

[0503] Figure 4A to Figure 4F FIG. 1 is a cross-sectional view schematically illustrating another example of a method for manufacturing a substrate device when the workpiece is a semiconductor wafer. Figure 1 The manufacturing method when the protective film shown is formed into the film 13 will be described.

[0504] In this specification, the method for manufacturing a substrate device using a protective film-forming film that does not constitute a protective film-forming composite sheet as described above may be referred to as “manufacturing method (2)”.

[0505] <Attachment process (2)>

[0506] In the attaching step (sometimes referred to as "attaching step (2)" in this specification) of the manufacturing method (2), the protective film forming film 13 that does not constitute the composite sheet for protective film formation, more specifically, the protective film forming film 13 from which the first release film 151 has been removed, is attached to the back surface 9b of the semiconductor wafer. Figure 4A As shown, a semiconductor wafer 902 with a protective film formed thereon is prepared, which is composed of a semiconductor wafer 9 and a protective film formed thereon 13 provided on a back surface 9b of the semiconductor wafer 9. The semiconductor wafer 902 with a protective film formed thereon is a workpiece with a protective film formed thereon.

[0507] The attaching step (2) may be the same as the attaching step (1) except that the protective film-forming film 13 including the second release film 152 is used instead of the protective film-forming composite sheet 101 .

[0508] <Thermal curing process (2)>

[0509] After the attaching step (2) of the manufacturing method (2), in the thermal curing step (sometimes referred to as "thermal curing step (2)" in this specification), the protective film forming film 13 is thermally cured to form a protective film 13'. Figure 4B As shown, a semiconductor wafer 9021 with a protective film is manufactured, which is composed of a semiconductor wafer 9 and a protective film 13' provided on the back surface 9b of the semiconductor wafer 9. The semiconductor wafer 9021 with a protective film is a workpiece with a protective film.

[0510] The thermal curing step (2) may be the same as the thermal curing step (1) except that the semiconductor wafer 902 with a protective film forming film is used instead of the semiconductor wafer 901 with a composite sheet for protective film forming.

[0511] The protective film-forming film 13 may be thermally cured in a state provided with the second release film 152 , or may be thermally cured after the second release film 152 is removed. Figure 4B , the case where the protective film forming film 13 is thermally cured after the second release film 152 is removed is shown.

[0512] <Processing and cutting process (2)>

[0513] After the attaching step (2) of the manufacturing method (2), in the processing and cutting step (sometimes referred to as "processing and cutting step (2)" in this specification), Figure 4C As shown, the processing sheet 80 is attached to the surface (second surface) 13b' of the protective film 13' which is opposite to the semiconductor wafer 9 side. Thus, a semiconductor wafer 9022 with the processing sheet and the protective film is obtained.

[0514] The processing sheet 80 is composed of a base material 81 and an adhesive layer 82 provided on one surface 81a of the base material 81. The surface (sometimes referred to as "first surface" in this specification) 82a of the adhesive layer 82 of the processing sheet 80 opposite to the base material 81 is attached to the second surface 13b' of the protective film 13'. The first surface 82a of the adhesive layer 82 is synonymous with the first surface 80a of the processing sheet 80.

[0515] The processing sheet 80 may have the same configuration as a known dicing sheet, or may have the same configuration as the support sheet 10 in the composite sheet 101 for forming a protective film.

[0516] Here, the case where the processing sheet 80 including the adhesive layer 82 is used is shown, but in the manufacturing method (2), a known processing sheet other than the processing sheet 80, such as a processing sheet composed only of a base material, may be used.

[0517] The processing sheet 80 can be attached to the protective film-forming film 13 by a known method, for example, the same method as that used to attach the protective film-forming composite sheet 101 to the semiconductor wafer 9 in the attaching step (1) of the manufacturing method (1).

[0518] In the processing and cutting step (2), the semiconductor wafer 9 is then processed (divided) on the processing sheet 80 to produce semiconductor chips 90, and the protective film 13' is cut. Figure 4D As shown, a plurality of semiconductor chips 91 with protective films are prepared. The plurality of semiconductor chips 91 with protective films are arranged and held on a processing sheet 80, and the semiconductor chips 91 with protective films and the processing sheet 80 constitute a semiconductor chip group 920 with protective films.

[0519] The semiconductor chip 91 with a protective film obtained in the manufacturing method (2) is the same as the semiconductor chip 91 with a protective film obtained in the manufacturing method (1).

[0520] In the processing and cutting step (2), the processing of the semiconductor wafer 9 and the cutting of the protective film 13' can be performed using the same method as in the processing and cutting step (1), except that the semiconductor wafer 9022 with the processing sheet and the protective film is used instead of the semiconductor wafer 9011 with the cured composite sheet for forming the protective film.

[0521] <Pick-up process (2)>

[0522] After the thermal curing step (2) and the processing and cutting step (2) of the manufacturing method (2), in the picking-up step (sometimes referred to as "picking-up step (2)" in this specification), Figure 4EAs shown, the semiconductor chip 91 with a protective film is separated and picked up from the processing sheet 80. In this way, the semiconductor chip 91 with a protective film can be taken out from the semiconductor chip group 920 with a protective film.

[0523] Figure 4E In the figure, the arrow P indicates the picking direction.

[0524] The semiconductor chip 91 with a protective film taken out in the pickup step (2) is the same as the semiconductor chip 91 with a protective film taken out in the pickup step (1).

[0525] The pickup step (2) may be the same as the pickup step (1) except that the semiconductor chip group 920 with a protective film is used instead of the semiconductor chip group 910 with a protective film.

[0526] <Installation process (2)>

[0527] In the manufacturing method (2), the mounting step (sometimes referred to as "mounting step (2)" in this specification) is performed after the pickup step (2) and the thermal curing step (2).

[0528] like Figure 4F As shown, the mounting step (2) is the same as the mounting step (1). Through the mounting step (2), the semiconductor chip 91 with a protective film is flip-chip connected to the connection pad on the circuit substrate 6 by the convex electrode in the semiconductor chip 91 with a protective film. In this process, the convex electrode in the semiconductor chip 91 with a protective film is melted and electrically connected to the connection pad. At this time, as in the manufacturing method (1), the light reflectivity of the protective film after heating at a high temperature is high, so it is possible to suppress the damage to the design of the device. In addition, the circuit substrate 6 has a plurality of semiconductor chips 91 with protective films. When they are heated at a high temperature, even if there is a deviation that may usually occur at the heating temperature, the color deviation in these protective films 130' after heating is suppressed, and it is also easy to obtain the design maintenance effect evenly.

[0529] <Other processes (2)>

[0530] The manufacturing method (2) may have other steps that are not part of any of the attaching step (2), the thermal curing step (2), the processing and cutting step (2), the picking up step (2), and the installing step (2) (sometimes referred to as "other steps (2)" in this specification), or may not have other steps that are not part of any of the attaching step (2), the thermal curing step (2), the processing and cutting step (2), the picking up step (2), and the installing step (2).

[0531] The type of the other step (2) and the timing of performing the other step (2) can be arbitrarily selected according to the purpose and are not particularly limited.

[0532] Examples of the other step (2) include a printing step (2), a grinding step (2), and a back grinding tape removal step (2) similar to those in the production method (1).

[0533] The printing step (2) can be performed after the attaching step (2), but is preferably performed between the thermal curing step (2) and the processing and cutting step (2).

[0534] In the printing step (2), for example, the protective film-forming film or the second surface of the protective film can be printed by irradiating the protective film-forming film or the second surface of the protective film with laser light from the outside of the substrate side of the processing sheet through the processing sheet.

[0535] The grinding step (2) is performed before the attaching step (2).

[0536] The back grinding tape removal step (2) is preferably performed after the attachment step (2).

[0537] <Timing of performing the thermal curing step (2)>

[0538] So far, the case where the heat curing step (2) is performed between the attaching step (2) and the processing and cutting step (2) has been described. However, in the manufacturing method (2), the timing of performing the heat curing step (2) is not limited to this, as long as it is performed after the attaching step (2). For example, the heat curing step (2) can be performed at any timing between the printing step (2) and the processing and cutting step (2), between the processing and cutting step (2) and the picking step (2), and between the picking step (2) and the mounting step (2).

[0539] Example

[0540] The present invention will be described in more detail below using specific examples, but the present invention is not limited to the following examples.

[0541] <Making materials of resin>

[0542] The formal names of the raw materials for producing the resins abbreviated in the examples and comparative examples are shown below.

[0543] MA: Methyl acrylate

[0544] HEA: 2-Hydroxyethyl Acrylate

[0545] <Raw materials for preparing the protective film forming composition>

[0546] The raw materials for preparing the protective film-forming composition are shown below, wherein the structural formula of the curing accelerator (C) is also shown.

[0547] [Polymer component (A)]

[0548] (A)-1: an acrylic resin obtained by copolymerizing MA (85 parts by mass) and HEA (15 parts by mass) (weight average molecular weight: 400,000, glass transition temperature: 6°C).

[0549] [Epoxy resin (B1)]

[0550] (B1)-1: Bisphenol A type epoxy resin ("jER828" manufactured by Mitsubishi Chemical Corporation, epoxy equivalent of 184 to 194 g / eq)

[0551] (B1)-2: Dicyclopentadiene type epoxy resin ("EPICLON HP-7200" manufactured by DIC CORPORATION, epoxy equivalent 254 to 264 g / eq)

[0552] [Thermosetting agent (B2)]

[0553] (B2)-1: dicyandiamide (thermally active latent epoxy resin curing agent, "DICY7" manufactured by Mitsubishi Chemical Corporation)

[0554] [Curing accelerator (C)]

[0555] (C)-1: Phthalate of DBU ("U-CAT SA810" manufactured by San-Apro Ltd., thermal alkali generator)

[0556] (C)-2: 2-phenyl-4,5-dihydroxymethylimidazole ("CUREZOL (registered trademark) 2PHZ" manufactured by SHIKOKU CHEMICALS CORPORATION)

[0557] (C)-3: Phenol salt of DBU ("U-CAT SA1" manufactured by San-Apro Ltd.)

[0558] (C)-4: 2-ethylhexanoate of DBU ("U-CAT SA102" manufactured by San-Apro Ltd.)

[0559] (C)-5: DBU formate ("U-CAT SA603" manufactured by San-Apro Ltd.)

[0560] (C)-6: 2-ethylhexanoic acid triethylmethylammonium salt (a salt composed of a triethylmethylammonium cation and a 2-ethylhexanoic acid ion, "SA 18X" manufactured by San-Apro Ltd.)

[0561] (C)-7: Benzyltriphenylphosphonium bromide (a salt composed of a benzyltriphenylphosphonium cation and a bromide ion, "U-CAT 5003" manufactured by San-Apro Ltd.)

[0562] (C)-8: Ethyltriphenylphosphonium methanesulfonate (a salt composed of an ethyltriphenylphosphonium cation and a methanesulfonate ion, "U-CAT 5050" manufactured by San-Apro Ltd.)

[0563] [Filling material (D)]

[0564] (D)-1: Silica filler (“SC2050MB” manufactured by Yaduma Co., Ltd., a spherical silica filler surface-modified with an epoxy compound, with an average particle size of 0.5 μm and a maximum particle size of 2.0 μm)

[0565] [Coupling agent (E)]

[0566] (E)-1: Silane coupling agent ("X-41-1056" manufactured by Shin-Etsu Chemical Co., Ltd., epoxy equivalent of 280 g / eq, oligomer silane coupling agent having epoxy group, methyl group and methoxy group)

[0567] [Colorant (I)]

[0568] (I)-1: Titanium oxide (white pigment, rutile titanium dioxide surface-treated with an inorganic compound having a hydroxyl group, average particle size 0.35 μm)

[0569] (I)-2: A pigment obtained by pigmenting a phthalocyanine blue pigment (Pigment Blue 15:3) / styrene acrylic resin=1 / 3 (mass ratio).

[0570] [Chemical formula 1]

[0571]

[0572] [Example 1]

[0573] <<Manufacturing of protective film-forming film>>

[0574] <Preparation of protective film-forming composition (III)>

[0575] A polymer component (A)-1 (125 parts by mass), an epoxy resin (B1)-1 (60 parts by mass), an epoxy resin (B1)-2 (40 parts by mass), a thermosetting agent (B2)-1 (2.4 parts by mass), a filler (D)-1 (360 parts by mass), a coupling agent (E)-1 (0.1 parts by mass), and a colorant (I)-1 (24.5 parts by mass) were dissolved or dispersed in methyl ethyl ketone and stirred at 23° C. to obtain a thermosetting protective film-forming composition (III) having a total concentration of 50% by mass of all components except the solvent. The blending amounts of the components except the methyl ethyl ketone shown here are all blending amounts of the target product excluding the solvent.

[0576] <Manufacturing of protective film-forming film>

[0577] A release film (second release film, "SP-PET502150" manufactured by LINTEC Corporation, 50 μm thick) obtained by subjecting one side of a polyethylene terephthalate film to a release treatment by silicone treatment was used, and the protective film-forming composition (III) obtained above was applied to the release-treated surface of the second release film, and dried at 100° C. for 2 minutes to produce a thermosetting protective film-forming film (25 μm thick).

[0578] Furthermore, a release film (first release film, "SP-PET381031" manufactured by LINTEC Corporation, thickness 38 μm) having one side of a polyethylene terephthalate film subjected to release treatment by silicone treatment was used, and the release-treated surface of the first release film was bonded to the exposed surface of the protective film-forming film obtained above, which side did not have the second release film. In summary, a laminated film was obtained, which was composed of a layer (single layer) of 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.

[0579] <<Evaluation of protective film forming film>>

[0580] <Measurement of light reflectance RH(x) and light reflectance RL(x), calculation of light reflectance difference ΔRH(x) and light reflectance change rate>

[0581] [Manufacturing of Silicon Wafers with Protective Film]

[0582] The back side of the silicon wafer is ground with a #2000 grinding wheel to obtain a silicon wafer with a thickness of 350 μm. The first release film is removed from the protective film forming film in the laminated film obtained above. Using a roller heated to a temperature of 70°C, the exposed surface of the protective film forming film (the surface having the first release film) is bonded to the ground surface of the silicon wafer after back grinding (attaching step (2)). Furthermore, the second release film is removed from the protective film forming film to obtain a silicon wafer with a protective film forming film, which is composed of a silicon wafer and a protective film forming film arranged on its back side (ground surface).

[0583] The obtained silicon wafer with a protective film was heated at 140° C. for 2 hours to thermally cure the protective film to form a protective film, thereby obtaining a silicon wafer with a protective film having a silicon wafer and a protective film provided on the back side thereof (thermal curing step (2)).

[0584] [Measurement of light reflectance RH(x) and calculation of light reflectance difference ΔRH(x)]

[0585] The obtained silicon wafer with a protective film was heated at 260° C. for 5 minutes to obtain a heated silicon wafer with a protective film.

[0586] For the exposed surface of the protective film in the heated silicon wafer with a protective film (the surface on the opposite side to the silicon wafer side), the amount of light of the total light reflected light combining the mirror reflected light (regular reflected light) and the diffuse reflected light is measured by the SCI method at intervals of 1 nm in the full wavelength range of 380 to 780 nm. Furthermore, for a reference plate made of barium sulfate, the amount of light of the total light reflected light is measured using the same method as above. In either case, the amount of light of the total light reflected light is measured using a UV-Vis spectrophotometer ("UV-VIS-NIR SPECTROPHOTOMETER UV-3600" manufactured by Shimadzu Corporation). In addition, the "large sample chamber MPC-3100" manufactured by Shimadzu Corporation is used as a sample holder, the "device with an integrating sphere ISR-3100" manufactured by Shimadzu Corporation is used as an integrating sphere, and the incident angle of the incident light to the measured object is set to 8°. Then, the ratio of the measured value of the protective film to the measured value of the reference plate ([measured value of the amount of light reflected from the total light of the protective film] / [measured value of the amount of light reflected from the total light of the reference plate]×100), that is, the relative total light reflectance of the protective film, is calculated and used as the light reflectance RH(x) (x=380~780).

[0587] The maximum value RH(x)max and the minimum value RH(x)min of the light reflectance RH(x) in the wavelength region of 400 to 700 nm were obtained, and the light reflectance difference ΔRH(x) (=RH(x)max-RH(x)min) was calculated from these values. The results are shown in Table 1.

[0588] [Measurement of light reflectance RL(x), calculation of change rate of light reflectance, calculation of |change rate of light reflectance|max]

[0589] The light reflectance RL(x) (x=380-780) was measured by the same method as that for measuring the light reflectance RH(x) except that the silicon wafer with the protective film was heated at 200°C for 5 minutes instead of 260°C for 5 minutes.

[0590] Then, in the wavelength range of 400 to 700 nm (x = 400 to 700), 301 light reflectance change rates (= (RL (x) - RH (x)) / RL (x) × 100) were calculated based on RL (x) and RH (x) at the same wavelength (same x value), and the maximum absolute value (|light reflectance change rate|max) was obtained. The results are shown in Table 1.

[0591] <Measurement of storage modulus E'(23) of protective film>

[0592] The protective film-forming films (thickness: 25 μm) of the eight laminated films obtained above were laminated one on another while removing the first release film and the second release film, thereby preparing a test laminated sheet (thickness: 200 μm).

[0593] The obtained test laminate was heated in an oven (under air atmosphere) at 140°C for 2 hours to thermally cure all protective film-forming films constituting the test laminate to form a protective film. A test piece having a width of 4.5 mm, a length of 30 mm, and a thickness of 200 μm was cut from the thus obtained heated test laminate.

[0594] The storage modulus E' of the test piece (protective film) was measured using a dynamic mechanical analyzer ("DMA Q800" manufactured by TA Instruments) under the following conditions while increasing the temperature at a constant rate. The measurement results of the storage modulus E'(23) when the temperature of the test piece was 23°C are shown in Table 1.

[0595] [Measurement conditions]

[0596] Measurement mode: Stretch mode

[0597] Grip distance (length of the E' measurement portion of the test piece): 20 mm

[0598] Measurement start temperature: 0°C

[0599] Measurement end temperature: 300°C

[0600] Heating rate: 3℃ / min

[0601] Frequency: 11Hz

[0602] Measuring atmosphere: Atmosphere

[0603] <Evaluation of the effect of maintaining the design of the protective film after heating>

[0604] [Manufacturing of Silicon Chips with Protective Film]

[0605] A silicon wafer with a protective film was produced by the same method as that used in the above-mentioned measurement of the light reflectance RH(x) and the light reflectance RL(x), except that a silicon wafer with a thickness of 100 μm was used.

[0606] A dicing tape ("ADWILL D-676H" manufactured by LINTEC Corporation) was attached to the exposed surface of the protective film in the obtained silicon wafer with a protective film. Next, a dicing blade was used to divide the silicon wafer into silicon chips of 2 mm×2 mm in size, and the protective film was cut along the periphery of the silicon chip, thereby obtaining a silicon chip with a protective film composed of a silicon chip and a cut protective film provided on the back side thereof (processing and cutting step (2)).

[0607] Next, five silicon chips with protective films are separated from the dicing tape and picked up (picking up step (2)).

[0608] [Evaluation of the effect of maintaining the design of the heated protective film]

[0609] The five silicon chips with protective films obtained above were placed in the temperature-stable central part of a heating tank of an oven (SPHH series manufactured by ESPEC CORP.), heated at 260° C. for 5 minutes, and then cooled to room temperature to obtain heated silicon chips with protective films.

[0610] A white circuit board (size: 70 mm×30 mm) having a light reflectivity of 39% or more in the entire wavelength region of 400 to 700 nm was prepared.

[0611] The five heated silicon chips with protective films are placed on the white surface of the white circuit substrate at intervals from each other. At this time, the exposed surface of the protective film in the heated silicon chip with protective film (the surface opposite to the silicon chip side) is oriented in the same direction as the white surface of the white circuit substrate.

[0612] Under the light of a fluorescent lamp (60W bulb-shaped fluorescent lamp) placed 1.5m above the evaluator and 2.0m above the white circuit substrate, three evaluators looked down at the five heated silicon chips with protective films in this state (mounted on the white circuit substrate) from a position 0.5m above and observed them with the naked eye for 3 seconds. Then, based on the number of evaluators who visually recognized at least one heated silicon chip with protective film (hereinafter referred to as "visual recognition evaluators"), the design maintenance effect of the heated protective film was evaluated according to the following criteria. The results are shown in Table 1.

[0613] [Evaluation criteria]

[0614] A: There was no visual evaluation panel (0 person), and the design maintenance effect of the heated protective film was extremely high, which was acceptable.

[0615] B: The visual evaluation was conducted by one person, and the design maintenance effect of the heated protective film was high, which was acceptable.

[0616] C: The visual evaluation was conducted by 2 or 3 people, and the design maintenance effect of the heated protective film was low, which was unacceptable.

[0617] <Evaluation of the effect of suppressing the color deviation of the heated protective film caused by the difference in the position of the protective film placed in the reflow furnace>

[0618] [Manufacturing of Silicon Chips with Protective Film]

[0619] A silicon wafer with a protective film was produced by the same method as that used in the above-mentioned measurement of the light reflectance RH(x) and the light reflectance RL(x), except that a silicon wafer with a thickness of 100 μm was used.

[0620] Next, a silicon chip with a protective film is manufactured using the same method as that used to evaluate the design maintenance effect of the heated protective film, except that the size of the silicon chip is 5 mm × 5 mm instead of 2 mm × 2 mm and the protective film is cut along the periphery of the silicon chip. Five silicon chips with the protective film are separated from the dicing tape and picked up (processing and cutting step (2), picking up step (2)).

[0621] [Evaluation of the Effect of Suppressing Color Deviation of Heated Protective Film]

[0622] The five silicon chips with protective films obtained above were placed on a conveyor belt of a reflow oven ("STR-2010M" manufactured by Senju Metal Industry Co., Ltd.). At this time, one of the five silicon chips with protective films was arranged in the center of the width direction of the conveyor belt (the direction perpendicular to the traveling direction of the conveyor belt), and the five silicon chips with protective films were arranged in the width direction of the conveyor belt at intervals of 50 mm from each other. In addition, the exposed surfaces of the protective films (the surfaces on the opposite side to the silicon chip side) of the five silicon chips with protective films were all oriented in the same direction as the conveying surface of the conveyor belt (i.e., facing upward).

[0623] In the reflow oven, the preheating temperature was set to 160° C., and the maximum reaching temperature of the silicon chips with protective films in the center of the width direction of the conveyor belt was set to 260° C. The conveyor belt was allowed to enter the reflow oven at a conveying speed of 1.7 cm / min. Thus, the five silicon chips with protective films placed on the conveyor belt as described above were put into the reflow oven and heated.

[0624] Next, prepare the same white circuit substrate as above, and let three evaluators look down and observe with naked eyes for 3 seconds from 0.3m above 5 heated silicon chips with protective films carried out of the reflow oven under the light of a fluorescent lamp (60W in the shape of a bulb) arranged 1.5m above the evaluator and 2.0m above the white circuit substrate. Then, based on the number of evaluators (hereinafter referred to as "visual recognition evaluators" as above) who visually recognize the color deviation of at least one heated protective film (color deviation between protective films), the effect of suppressing the color deviation of the heated protective film is evaluated according to the following criteria. The results are shown in Table 1.

[0625] [Evaluation criteria]

[0626] A: There was no visual evaluation panelist (0 person), and the effect of suppressing the color deviation of the heated protective film was extremely high, which was acceptable.

[0627] B: The visual evaluation was conducted by one person, and the effect of suppressing the color deviation of the heated protective film was high, which was acceptable.

[0628] C: The number of visual evaluation panelists is 2 or 3, and the effect of suppressing the color deviation of the heated protective film is low, which is unacceptable.

[0629] <<Production and evaluation of protective film-forming film>>

[0630] [Examples 2 to 9, Comparative Examples 1 to 2]

[0631] A protective film-forming film was produced and evaluated by the same method as in Example 1 except that either or both of the types and amounts of the components blended when preparing the protective film-forming composition (III) were changed so that the types and contents of the components contained in the protective film-forming composition (III) were as shown in Table 1 or Table 2. The results are shown in Table 1 or Table 2.

[0632] The description of “-” in the column of “Content components (content (parts by mass))” of “Protective film-forming film” in Tables 1 and 2 means that the component is not blended (does not contain the component).

[0633] The description of “Ratio (mass %) of content of imidazole-based curing accelerator” in the column “Protective film-forming film” in Tables 1 and 2 indicates “Ratio (mass %) of content of imidazole-based curing accelerator in protective film-forming film relative to the total mass of protective film-forming film”.

[0634] The description of “ratio (mass %) of content of white pigment” in the column of “protective film forming film” in Tables 1 and 2 indicates “ratio (mass %) of content of white pigment in protective film forming film relative to total mass of protective film forming film”.

[0635] The entry “-” in the column “Evaluation results” in Table 1 means that the evaluation of that item was not conducted.

[0636] [Table 1]

[0637]

[0638] [Table 2]

[0639]

[0640] From the above results, it can be seen that in Examples 1 to 9, RH(x)min is 28.1% or more, and the light reflectance is high even when the protective film is heated at a high temperature of 260°C. The protective film-forming films of Examples 1 to 9 contain white pigments, but do not contain imidazole compounds headed by imidazole curing accelerators. In the protective film-forming films of Examples 1 to 9, the content of the white pigment is 3.99% by mass or more relative to the total mass of the protective film-forming films.

[0641] The protective film-forming films of Examples 1 to 2 and 4 to 9 and the protective films immediately after being formed were white, and even after being heated at 260° C., the design maintenance effect of the heated protective films was high.

[0642] The protective film of Example 3 contains a phthalocyanine blue pigment in addition to a white pigment. The protective film of Example 3 and the protective film just formed are white with a light blue tint (light blue white). The color of the protective film is light blue after heating at 260°C, but the design maintenance effect is high.

[0643] In Examples 1 to 9, ΔRH(x) was 16% or less, and in Examples 1 to 2 and 4 to 9, ΔRH(x) was 12.7% or less.

[0644] Furthermore, the protective films of Examples 1 to 3 all had the same color regardless of the arrangement position (position on the transport conveyor) when heated at 260° C., and color deviation between the heated protective films was suppressed.

[0645] In Examples 1 to 9, |the rate of change in light reflectance|max was 12.1% or less.

[0646] The storage modulus E'(23) of the protective films of Examples 1 to 9 was 812 MPa or more, and the storage modulus E'(23) of the protective films of Examples 2 to 9 was particularly high, 1104 MPa or more.

[0647] The protective film-forming film of Example 1 does not contain a curing accelerator (C), but the protective film-forming films of Examples 2 to 9 contain a curing accelerator (C) (thermal base generator) other than the imidazole-based curing accelerator.

[0648] In contrast, in Comparative Examples 1 and 2, RH(x)min was 24.6% or less, and when the protective film was heated at a high temperature, its light reflectance was low. The protective film-forming film of Comparative Example 1 contained a white pigment, and on the other hand, it also contained an imidazole-based curing accelerator, and its influence could not be suppressed. The protective film-forming film of Comparative Example 2 contained an imidazole-based curing accelerator, but did not contain a white pigment.

[0649] In Comparative Example 2, RH(x)min was 14.7%, which was extremely low, and therefore the storage modulus E' of the protective film was not measured.

[0650] The protective film formed film and the protective film immediately after the formation of Comparative Example 1 were white, but the protective film after heating at 260° C. was light yellow, and the design maintenance effect of the heated protective film was low.

[0651] The protective film-forming film of Comparative Example 2 and the protective film immediately after being formed were white with a yellow tint (light yellowish white), and the color of the protective film became darker after being heated at 260° C. That is, the design maintenance effect of the heated protective film was low.

[0652] Furthermore, the color of the protective film of Comparative Example 2 (the color of the heated protective film) varied regardless of the placement position (position on the transport conveyor) when heated at 260° C. In Comparative Example 2, |change rate of light reflectance|max was 25.5%.

[0653] Industrial Applicability

[0654] The present invention is a protective film for protecting a workpiece to be mounted on a circuit board having a high light reflectivity such as white, and can be used as a protective film for use in a high temperature heating environment of about 260°C.

Claims

1. A protective film-forming film, which is a thermosetting protective film-forming film, The protective film, which is a thermally cured product of the protective film-forming film, was heated at 260° C. for 5 minutes and the light reflectance of the heated protective film was measured. The light reflectance was 26% or more in the entire wavelength region of 400 to 700 nm.

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

3. The protective film-forming film according to claim 1 or 2, wherein: The protective film forming film is used to form a protective film at any position of a workpiece obtained by processing the workpiece. A workpiece with a protective film, which includes the workpiece and the protective film provided at an arbitrary position of the workpiece, is mounted on a circuit board. The circuit substrate has a light reflectivity of 30% or more in the full wavelength region of 400 to 700 nm.

4. The protective film-forming film according to claim 1 or 2, wherein: In the protective film-forming film, the content of the imidazole-based curing accelerator is less than 0.3% by mass based on the total mass of the protective film-forming film.

5. The protective film-forming film according to claim 1 or 2, wherein: The protective film-forming film contains a thermal base generator.

6. The protective film-forming film according to claim 1 or 2, wherein: After heating the protective film at 200° C. for 5 minutes, the light reflectance RL(x) was measured at a wavelength interval of 1 nm in the entire wavelength range of 400 to 700 nm. The protective film was heated at 260° C. for 5 minutes, and the light reflectance RH(x) was measured at a wavelength interval of 1 nm in the entire wavelength range of 400 to 700 nm. When the change rate of the light reflectance at each wavelength is calculated from the RL(x) and RH(x) at the same wavelength by the following formula, the maximum value of the absolute values ​​of all the change rates is less than 18%: The change rate of light reflectivity (%) = ((RL(x)-RH(x)) / RL(x)×100).

7. The protective film-forming film according to claim 1 or 2, wherein: For the protective film after heating at 260°C for 5 minutes, when the light reflectance RH(x) is measured at a wavelength interval of 1 nm in the full wavelength range of 400~700nm, the difference between the maximum value RH(x)max of the light reflectance RH(x) and the minimum value RH(x)min of the light reflectance RH(x) is less than 13%.

8. A method for manufacturing a substrate device, which is a method for manufacturing a substrate device using a protective film-forming film or a composite sheet for protective film formation, wherein: The protective film-forming film is the protective film-forming film according to claim 1 or 2, The composite sheet for forming a protective film comprises a support sheet and the protective film-forming film according to claim 1 or 2 provided on one surface of the support sheet. The manufacturing method has the following features: an attaching step of attaching the protective film-forming film that does not constitute the protective film-forming composite sheet or the protective film-forming film in the protective film-forming composite sheet to a surface of the workpiece that is opposite to the surface having the convex electrodes; a thermal curing step, wherein, after the attaching step, the protective film-forming film is thermally cured to form a protective film; A processing and cutting process, wherein, after the attaching process, when the protective film-forming film that does not constitute the protective film-forming composite sheet is used, a processing sheet is attached to the surface of the protective film-forming film or the protective film opposite to the workpiece side, and the workpiece is processed on the processing sheet to produce a workpiece processed object, and the protective film-forming film or the protective film is cut off; when the protective film-forming composite sheet is used, the workpiece is processed on the support sheet to produce a workpiece processed object, and the protective film-forming film or the protective film is cut off, thereby producing a workpiece processed object with a protective film-forming film or a workpiece processed object with a protective film, the workpiece processed object with a protective film-forming film comprises the workpiece processed object and the surface of the workpiece processed object arranged on the opposite side of the surface having the convex electrode after the protective film is cut off, and the workpiece processed object with a protective film comprises the workpiece processed object and the surface of the workpiece processed object arranged on the opposite side of the surface having the convex electrode after the protective film is cut off; A picking-up process, wherein after the processing and cutting process, the workpiece with the protective film formed thereon or the workpiece with the protective film is separated from the processing sheet or the supporting sheet and picked up; and The mounting step includes, after the picking up step and the heat curing step, bringing the convex electrode in the workpiece with the protective film into contact with a circuit substrate, and then heating the workpiece with the protective film to melt the convex electrode and connect it to the circuit substrate.

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