JP7190483B2 - Composite sheet for protective film formation - Google Patents

Description

TECHNICAL FIELD The present invention relates to a support sheet and a composite sheet for forming a protective film.

2. Description of the Related Art In recent years, semiconductor devices have been manufactured by applying a mounting method called a so-called face down method. In the face-down method, a semiconductor chip having electrodes such as bumps on a circuit surface is used, and the electrodes are joined to a substrate. Therefore, the back surface of the semiconductor chip on the side opposite to the circuit surface may be exposed.

A resin film containing an organic material is formed as a protective film on the exposed back surface of the semiconductor chip, and the semiconductor chip may be incorporated into a semiconductor device as a semiconductor chip with a protective film. A protective film is used to prevent cracks from occurring in a semiconductor chip after a dicing process or packaging.

Such a protective film is formed, for example, by curing a curable film for forming a protective film. In some cases, a non-curing protective film-forming film whose physical properties have been adjusted is used as it is as a protective film. Then, the protective film forming film is used by being attached to the back surface of the semiconductor wafer. For example, the protective film-forming film may be attached to the back surface of the semiconductor wafer in the state of a protective film-forming composite sheet integrated with a support sheet used during processing of the semiconductor wafer. In some cases, it is attached to the back surface of the semiconductor wafer in an unintegrated state.

After the protective film-forming composite sheet is attached to the back surface of the semiconductor chip by the protective film-forming film therein, the protective film-forming film is cured to form a protective film at an appropriate timing. Cutting of the forming film or protective film, division of the semiconductor wafer into semiconductor chips (dicing), semiconductor chip with protective film forming film after cutting or protective film on the back surface (semiconductor chip with protective film forming film or protective film The film-attached semiconductor chip) is appropriately picked up from the support sheet. When a semiconductor chip with a protective film-forming film is picked up, the protective film-forming film is cured to form a semiconductor chip with a protective film. Finally, the semiconductor chip with a protective film is used to manufacture a semiconductor device is manufactured. Thus, the support sheet in the protective film-forming composite sheet can be used as a dicing sheet. When the film for forming a protective film is non-curable, the film for forming a protective film is treated as it is as a protective film in each of these steps.

On the other hand, after the protective film-forming film is attached to the back surface of the semiconductor wafer without being integrated with the support sheet, the side of the protective film-forming film opposite to the attached surface of the semiconductor wafer is exposed. A support sheet is attached to the face. Thereafter, a semiconductor chip with a protective film or a semiconductor chip with a film for forming a protective film is obtained by the same method as in the case of using the composite sheet for forming a protective film, and a semiconductor device is manufactured. In this case, the protective film-forming film is attached to the back surface of the semiconductor wafer without being integrated with the support sheet. configure.

As such a composite sheet for forming a protective film, for example, a dicing tape (supporting sheet) having a substrate having an uneven surface and an adhesive layer laminated on the uneven surface side of the substrate (support sheet), and this dicing A dicing tape-integrated film for protecting the back surface of a semiconductor (composite sheet for forming a protective film) comprising a film for protecting the back surface of a semiconductor (film for forming a protective film) laminated on an adhesive layer of the tape, the dicing tape A dicing tape-integrated film for protecting the back surface of a semiconductor having a haze of 45% or less is disclosed (see Patent Document 1).

However, in the composite sheet for forming a protective film (dicing tape-integrated film for protecting the back surface of a semiconductor) disclosed in Patent Document 1, an adhesive layer is laminated on the roughened surface side of the base material, so that the adhesive The effect of the unevenness described above may appear on the adhesive layer and the film for forming a protective film (film for protecting the back surface of a semiconductor) laminated on the adhesive layer. For example, the surface of the pressure-sensitive adhesive layer on the side of the film for forming a protective film becomes an uneven surface, so that there is a region (non-bonded region) between the pressure-sensitive adhesive layer and the film for forming a protective film where they are not bonded. may occur and their lamination properties may be reduced. In addition, the surface of the adhesive layer side of the protective film or protective film forming film may be printed by laser irradiation, but the thickness of the adhesive layer becomes uneven, and in the part where the adhesive layer is thick , the visibility of printing through the base material and the adhesive layer may decrease.

Japanese Patent No. 5432853

The present invention provides a support sheet comprising a pressure-sensitive adhesive layer on the uneven surface side of a base material, and a protective film-forming composite sheet comprising a protective film-forming film on the pressure-sensitive adhesive layer, wherein the pressure-sensitive adhesive A support sheet capable of realizing good lamination of a layer and a protective film-forming film and good print visibility through the support sheet of the protective film or the protective film-forming film; and the support sheet. An object of the present invention is to provide a composite sheet for forming a protective film.

The present invention provides a support sheet comprising a base material and a pressure-sensitive adhesive layer on the base material, wherein the surface of the base material on the side of the pressure-sensitive adhesive layer is an uneven surface, and five points on the support sheet When the test pieces were cut out and the minimum and maximum values of the thickness of the pressure-sensitive adhesive layer were obtained for each of these five test pieces, the average value of the minimum values was 1.5 μm or more, and the average value of the maximum values A support sheet having a value of 9 μm or less is provided.

In the support sheet of the present invention, the pressure-sensitive adhesive layer may be in direct contact with the uneven surface of the substrate.
The present invention also provides a protective film-forming composite sheet comprising a protective film-forming film on the pressure-sensitive adhesive layer in the support sheet.

By constructing a protective film-forming composite sheet using the support sheet of the present invention, it is possible to obtain good lamination properties between the pressure-sensitive adhesive layer and the protective film-forming film, and the support sheet for the protective film or the protective film-forming film. and good print visibility can be realized.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows typically the support sheet which concerns on one Embodiment of this invention, and the composite sheet for protective film formation. BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows typically the composite sheet for protective film formation which concerns on one Embodiment of this invention with a support sheet. BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows typically the composite sheet for protective film formation which concerns on one Embodiment of this invention with a support sheet. FIG. 2 is an enlarged cross-sectional view of the support sheet and protective film-forming composite sheet shown in FIG. 1 ;

◇Supporting sheet and composite sheet for forming a protective film The supporting sheet according to one embodiment of the present invention is a supporting sheet comprising a substrate and an adhesive layer on the substrate, The surface on the side of the adhesive layer is an uneven surface, and test pieces are cut out from five locations on the support sheet. The average value of the minimum values (herein, sometimes referred to as “S value”) is 1.5 μm or more, and the average value of the maximum values (herein, referred to as “L value”) existing) is 9 μm or less.
Moreover, the composite sheet for protective film formation which concerns on one Embodiment of this invention is equipped with the film for protective film formation on the adhesive layer in the said support sheet.

The support sheet has a pressure-sensitive adhesive layer on the uneven surface side of the base material, and in the protective film-forming composite sheet comprising this support sheet, the influence of the uneven surface is suppressed.
More specifically, when the S value of the pressure-sensitive adhesive layer is 1.5 μm or more, the layerability between the pressure-sensitive adhesive layer and the protective film-forming film is improved. In the present specification, the term "stackability" means the degree of normality of the stacking state of two target layers, unless otherwise specified. "Good lamination property" means, for example, that there is no non-bonding region (void) between two adjacent target layers, or that the number of non-bonding regions is small and the non-bonding It means that the interlayer distance of the region is small.
On the other hand, when the L value of the pressure-sensitive adhesive layer is 9 μm or less, the print visibility of the protective film or protective film-forming film through the support sheet is improved.

The test pieces were cut out from the support sheet at five locations, and were obtained by cutting the support sheet over the entire thickness direction. The specimen is a strip with all layers forming the support sheet.

The size of the test piece is not particularly limited, but the length of one side of the laminated surface or exposed surface of each layer (substrate, adhesive layer, etc.) constituting the test piece is preferably 2 mm or more. By using a test piece having such a size, the S value and L value of the pressure-sensitive adhesive layer can be obtained with higher accuracy.
The maximum value of the length of one side is not particularly limited. For example, the length of one side is preferably 10 mm or less in terms of easier preparation of the test piece.

The planar shape of the test piece, that is, the shape of the laminated surface or the exposed surface of each layer (base material, pressure-sensitive adhesive layer, etc.) constituting the test piece is preferably polygonal, which makes it easier to cut out the test piece. In terms of points, a square shape is more preferable.

A preferable test piece is, for example, one in which the laminated surface or exposed surface of each layer (substrate, pressure-sensitive adhesive layer, etc.) constituting the test piece has a square shape with a size of 3 mm×3 mm. However, this is an example of a preferred test strip.

The cut-out positions of the five test pieces on the support sheet are not particularly limited, but in order to obtain the S value and L value of the pressure-sensitive adhesive layer with higher accuracy, consideration is given to the planned lamination position of the protective film forming film described later. can be selected by
For example, among the planned stacking positions of one protective film-forming film on the support sheet, one position where the center (center of gravity) of the protective film-forming film is planned to be arranged, and a position near the peripheral edge of the protective film-forming film There are five locations, ie, four locations that are scheduled to be located approximately point-symmetrically with respect to the central (center of gravity) portion.

In the supporting sheet, the distance between the centers (centers of gravity) of the cutting positions of the test pieces is preferably 50 to 200 mm. By doing so, the S value and L value of the pressure-sensitive adhesive layer can be obtained with higher accuracy.

In order to obtain the S value and L value of the adhesive layer from the test piece, a new cross section is formed in the test piece, and in this formed cross section, the minimum thickness of the adhesive layer for each test piece and the maximum value.
The cross section to be newly formed may be only one side or two or more sides per test piece, but usually only one side is sufficient.
Then, the S value and the L value should be calculated from these at least five minimum and maximum values.

Cross-sections can be formed in the test piece by known methods. For example, by using a known cross-section sample preparation apparatus (cross-section polisher), variations can be suppressed and cross-sections can be formed in the test piece with high reproducibility.

The minimum value and maximum value of the thickness of the pressure-sensitive adhesive layer can be measured, for example, by observing the cross section of the test piece using a scanning electron microscope (SEM).

In the cross section of each test piece, the area for measuring the minimum and maximum thickness of the pressure-sensitive adhesive layer is the direction perpendicular to the lamination direction of each layer (base material, pressure-sensitive adhesive layer, etc.) constituting the test piece. It is preferably in the range of 50 to 1500 μm (in a direction generally parallel to the laminated surface or exposed surface of each layer). By doing so, the minimum value and maximum value of the thickness of the pressure-sensitive adhesive layer can be measured with high efficiency and high accuracy.

When comparing the minimum value of the thickness of the pressure-sensitive adhesive layer between the support sheet at the stage not constituting the protective film-forming composite sheet and the support sheet constituting the protective film-forming composite sheet , These minimum values are the same as each other, or the minimum value in the support sheet constituting the protective film-forming composite sheet is slightly smaller, and even if it is smaller in this way , the difference is negligible.
The same applies to the maximum thickness of the pressure-sensitive adhesive layer. That is, the maximum value of the thickness of the adhesive layer is compared between the support sheet at the stage not constituting the protective film-forming composite sheet and the support sheet constituting the protective film-forming composite sheet. In this case, these maximum values are the same as each other, or the maximum value of the support sheet constituting the protective film-forming composite sheet is slightly smaller, and thus smaller. In both cases, the difference is negligible.
Therefore, the S value and L value of the pressure-sensitive adhesive layer are obtained by using a test piece cut out from the protective film-forming composite sheet instead of the support sheet, and using the same method as in the case of using the test piece cut out from the support sheet. good too. When using a test piece cut out from the protective film-forming composite sheet in this way, if the S value of the adhesive layer is 1.5 μm or more and the L value of the adhesive layer is 9 μm or less, this protective film formation The composite sheet for use reflects the effects of the present invention described above.

That is, the protective film-forming composite sheet according to one embodiment of the present invention is a protective film-forming composite sheet comprising a protective film-forming film on the pressure-sensitive adhesive layer in the support sheet, wherein the protective film is Test pieces were cut out from five locations on the forming composite sheet, and when the minimum and maximum values of the thickness of the pressure-sensitive adhesive layer were obtained for each of these five test pieces, the average value (S value) of the minimum values was It becomes 1.5 μm or more, and the average value (L value) of the maximum values becomes 9 μm or less.

The test piece cut out from the composite sheet for forming a protective film was obtained by cutting the composite sheet for forming a protective film in the entire thickness direction, and the entirety of the composite sheet for forming a protective film was obtained. A strip with layers.

Hereinafter, the overall configuration of the protective film-forming composite sheet of the present invention will be described with reference to the drawings. In addition, in the drawings used in the following description, in order to make the features of the present invention easier to understand, there are cases where the main parts are enlarged for convenience, and the dimensional ratios of each component are the same as the actual ones. not necessarily.

FIG. 1 is a cross-sectional view schematically showing a support sheet and a protective film-forming composite sheet according to one embodiment of the present invention.
The protective film-forming composite sheet 1A shown here includes a substrate 11, an adhesive layer 12 on the substrate 11, and a protective film-forming film 13 on the adhesive layer 12. FIG. The support sheet 10 is a laminate of a substrate 11 and an adhesive layer 12, and the protective film-forming composite sheet 1A is, in other words, one surface of the support sheet 10 (in this specification, the "first surface"). ) 10a and a protective film forming film 13 is laminated thereon. In addition, the protective film-forming composite sheet 1A further includes a release film 15 on the protective film-forming film 13 .

In the protective film-forming composite sheet 1A, the pressure-sensitive adhesive layer 12 is laminated on one surface 11a of the substrate 11 (which may be referred to herein as the “first surface”). The protective film-forming film 13 is laminated on the entire surface of the surface 12a opposite to the substrate 11 side (in this specification, sometimes referred to as the "first surface"), and the protective film-forming film 13, A jig adhesive layer 16 is formed on a portion of the surface 13a opposite to the pressure-sensitive adhesive layer 12 side (in this specification, this may be referred to as a "first surface"), that is, a region near the peripheral edge. Of the first surface 13 a of the laminated protective film forming film 13 , the surface on which the jig adhesive layer 16 is not laminated is in contact with the protective film forming film 13 of the jig adhesive layer 16 . A release film 15 is laminated on the surface 16a (upper surface and side surface) that is not exposed.
In FIG. 1, reference numeral 13b indicates the surface of the protective film-forming film 13 on the pressure-sensitive adhesive layer 12 side (in this specification, it may be referred to as "second surface").

The jig adhesive layer 16 may have, for example, a single-layer structure containing an adhesive component, or a plurality of layers in which layers containing an adhesive component are laminated on both sides of a sheet serving as a core material. It may be structural.

In the protective film-forming composite sheet 1A, the first surface 11a of the substrate 11 is an uneven surface.
Moreover, the pressure-sensitive adhesive layer 12 is provided in direct contact with the first surface (uneven surface) 11 a of the substrate 11 . Therefore, the surface 12b of the pressure-sensitive adhesive layer 12 on the side of the base material 11 (in this specification, may be referred to as the "second surface") is an uneven surface.

In the protective film-forming composite sheet 1A, the surface 11b of the substrate 11 on the side opposite to the pressure-sensitive adhesive layer 12 side (herein sometimes referred to as the "second surface") 11b has an uneven surface and a smooth surface. Any surface (non-roughened surface, glossy surface) may be used, but a smooth surface is preferred. The second surface 11b of the substrate 11 can also be said to be the surface 10b of the support sheet 10 opposite to the protective film forming film 13 side (in this specification, sometimes referred to as the "second surface") 10b. .
"Uneven surface" and "smooth surface" will be described later in detail.

The composite sheet 1A for forming a protective film shown in FIG. The upper surface of the surface 16a of the tool adhesive layer 16 is used by being attached to a tool such as a ring frame.

FIG. 2 is a cross-sectional view schematically showing a protective film-forming composite sheet according to another embodiment of the present invention together with a support sheet.
In the drawings after FIG. 2, the same constituent elements as those shown in already explained figures are given the same reference numerals as in the already explained figures, and detailed explanations thereof will be omitted.

The protective film-forming composite sheet 1B shown here is the same as the protective film-forming composite sheet 1A shown in FIG. 1 except that the jig adhesive layer 16 is not provided. That is, in the protective film-forming composite sheet 1B, the adhesive layer 12 is laminated on the first surface 11a of the base material 11, and the protective film-forming film 13 is laminated on the entire first surface 12a of the adhesive layer 12. , a release film 15 is laminated on the entire surface of the first surface 13 a of the protective film forming film 13 .

In the protective film-forming composite sheet 1B as well, the first surface 11a of the substrate 11 is an uneven surface.
Moreover, the pressure-sensitive adhesive layer 12 is provided in direct contact with the first surface (uneven surface) 11 a of the substrate 11 . Therefore, the surface (second surface) 12b of the pressure-sensitive adhesive layer 12 on the substrate 11 side is an uneven surface.
Also in the protective film-forming composite sheet 1B, the second surface 11b of the substrate 11 (in other words, the second surface 10b of the support sheet 10) may be either an uneven surface or a smooth surface (non- uneven surface). is preferably a smooth surface.

In the protective film-forming composite sheet 1B shown in FIG. 2, a semiconductor wafer (not shown) is attached to a central portion of the first surface 13a of the protective film-forming film 13 in a state where the release film 15 is removed. ), and the area near the periphery is attached to a jig such as a ring frame for use.

FIG. 3 is a cross-sectional view schematically showing a protective film-forming composite sheet according to still another embodiment of the present invention together with a support sheet.
The protective film-forming composite sheet 1C shown here is the same as the protective film-forming composite sheet 1B shown in FIG. 2 except that the shape of the protective film-forming film is different. That is, the protective film-forming composite sheet 1</b>C has a substrate 11 , an adhesive layer 12 on the substrate 11 , and a protective film-forming film 23 on the adhesive layer 12 . The support sheet 10 is a laminate of a substrate 11 and an adhesive layer 12, and the protective film-forming composite sheet 1C is, in other words, the first surface (surface on the protective film-forming film 23 side) 10a of the support sheet 10. It has a configuration in which a protective film forming film 23 is laminated thereon. In addition, the protective film-forming composite sheet 1</b>C further includes a release film 15 on the protective film-forming film 23 .

In the protective film-forming composite sheet 1C, the pressure-sensitive adhesive layer 12 is laminated on the first surface 11a of the base material 11, and the protective film is formed on a part of the first surface 12a of the pressure-sensitive adhesive layer 12, that is, the central region. film 23 is laminated. Then, of the first surface 12a of the adhesive layer 12, the area where the protective film forming film 23 is not laminated, and the surface 23a of the protective film forming film 23 that is not in contact with the adhesive layer 12 (upper surface and A release film 15 is laminated on the side surface).
In FIG. 3, reference numeral 23b indicates the surface of the protective film-forming film 23 on the pressure-sensitive adhesive layer 12 side (in this specification, it may be referred to as the "second surface").

When the protective film-forming composite sheet 1C is viewed from above in a plan view, the protective film-forming film 23 has a smaller surface area than the adhesive layer 12 and has, for example, a circular shape.

In the protective film-forming composite sheet 1C as well, the first surface 11a of the substrate 11 is an uneven surface.
Moreover, the pressure-sensitive adhesive layer 12 is provided in direct contact with the first surface (uneven surface) 11 a of the substrate 11 . Therefore, the surface (second surface) 12b of the pressure-sensitive adhesive layer 12 on the substrate 11 side is an uneven surface.
Also in the protective film-forming composite sheet 1C, the second surface 11b of the substrate 11 (in other words, the second surface 10b of the support sheet 10) may be either an uneven surface or a smooth surface (non- uneven surface). is preferably a smooth surface.

In the protective film-forming composite sheet 1C shown in FIG. 3, the back surface of a semiconductor wafer (not shown) is adhered to the surface 23a of the protective film-forming film 23 in a state in which the release film 15 is removed. A region of the first surface 12a of 12 where the protective film forming film 23 is not laminated is used by being attached to a jig such as a ring frame.

In addition, in the protective film-forming composite sheet 1C shown in FIG. 3, the first surface 12a of the pressure-sensitive adhesive layer 12, in the region where the protective film-forming film 23 is not laminated, is the same as that shown in FIG. A jig adhesive layer may be laminated (not shown). In the protective film forming composite sheet 1C having such a jig adhesive layer, the upper surface of the jig adhesive layer is attached to a jig such as a ring frame in the same manner as the protective film forming composite sheet shown in FIG. Affixed to tools and used.

As described above, the protective film-forming composite sheet may be provided with an adhesive layer for a jig, regardless of the form of the support sheet and the protective film-forming film. However, as shown in FIG. 1, the protective film-forming composite sheet having the jig adhesive layer preferably has the jig adhesive layer on the protective film-forming film.

The composite sheet for forming a protective film according to one embodiment of the present invention is not limited to those shown in FIGS. 1 to 3, and some of those shown in FIGS. may be modified or deleted, or other configurations may be added to those described above.

For example, in the protective film-forming composite sheet shown in FIGS. 1 to 3, an intermediate layer may be provided between the substrate 11 and the pressure-sensitive adhesive layer 12 . That is, in the protective film-forming composite sheet of the present invention, the support sheet may be configured by laminating a base material, an intermediate layer and an adhesive layer in this order in the thickness direction thereof. Any intermediate layer can be selected depending on the purpose.
In the protective film-forming composite sheet shown in FIGS. 1 to 3, layers other than the intermediate layer may be provided at arbitrary locations.
Further, in the protective film-forming composite sheet, a partial gap may be formed between the release film and the layer in direct contact with the release film.
In the protective film-forming composite sheet, the size and shape of each layer can be arbitrarily adjusted according to the purpose.

However, as shown in FIGS. 1 to 3, in the protective film-forming composite sheet, the adhesive layer is in direct contact with the uneven surface (first surface) of the substrate, in other words, It is preferable that the pressure-sensitive adhesive layer is laminated on the substrate in direct contact without providing an intermediate layer between the adhesive layer.
Further, in the protective film-forming composite sheet, the protective film-forming film is in direct contact with the first surface of the adhesive layer, in other words, another It is preferable that no layer is provided and the film for forming a protective film is laminated on the pressure-sensitive adhesive layer in direct contact therewith.
The protective film-forming composite sheet satisfies all of these conditions, that is, the substrate, the adhesive layer and the protective film-forming film are laminated in this order in direct contact with each other in the thickness direction. is more preferred.

The support sheet is preferably transparent.
The support sheet may be colored depending on the purpose, and other layers may be deposited thereon.
For example, when the protective film-forming film is energy ray-curable, the support sheet is preferably permeable to energy rays.

As used herein, the term "energy ray" means an electromagnetic wave or charged particle beam that has an energy quantum, and examples thereof include ultraviolet rays, radiation, electron beams, and the like. Ultraviolet rays can be applied by using, for example, a high-pressure mercury lamp, a fusion lamp, a xenon lamp, a black light, an LED lamp, or the like as an ultraviolet light source. The electron beam can be generated by an electron beam accelerator or the like.
As used herein, "energy ray-curable" means the property of curing by irradiation with energy rays, and "non-energy ray-curable" means the property of not curing even when irradiated with energy rays. do.

In the support sheet, the transmittance of light having a wavelength of 375 nm is preferably 30% or more, more preferably 50% or more, and particularly preferably 70% or more. When the protective film-forming film is irradiated with energy rays (ultraviolet rays) through the support sheet, the degree of curing of the protective film-forming film is further improved when the light transmittance is within such a range.
The upper limit of the transmittance of light having a wavelength of 375 nm in the support sheet is not particularly limited. For example, the light transmittance may be 95% or less.

In the support sheet, the transmittance of light having a wavelength of 532 nm is preferably 30% or more, more preferably 50% or more, and particularly preferably 70% or more. When the protective film-forming film or the protective film is irradiated with a laser beam through the support sheet and the light transmittance is within such a range, the printing can be performed more clearly.
The upper limit of the transmittance of light having a wavelength of 532 nm in the support sheet is not particularly limited. For example, the light transmittance may be 95% or less.

In the support sheet, the transmittance of light having a wavelength of 1064 nm is preferably 30% or more, more preferably 50% or more, and particularly preferably 70% or more. When the protective film-forming film or the protective film is irradiated with a laser beam through the support sheet and the light transmittance is within such a range, the printing can be performed more clearly.
The upper limit of the transmittance of light having a wavelength of 1064 nm in the support sheet is not particularly limited. For example, the light transmittance may be 95% or less.

The transmission visibility of the support sheet is preferably 30 or more, more preferably 100 or more, and particularly preferably 200 or more. When the transmission definition is within such a range, it becomes easier to check floating and peeling of the protective film-forming film, defective printing, chipping, and the like through the support sheet.
The transmission visibility of the support sheet is not particularly limited. For example, the transmission sharpness may be 430 or less.
The transmission visibility of the support sheet can be measured according to JIS K 7374-2007.

Next, each layer constituting the support sheet and the protective film-forming composite sheet will be described in detail.

○ Substrate The substrate is sheet-like or film-like and has an uneven surface.

As used herein, the term “uneven surface” means a surface having a maximum height roughness Rz defined in JIS B 0601:2013 of 0.01 μm or more.
In addition, the "smooth surface" means a highly smooth surface rather than an uneven surface, and is also called a "non- uneven surface" or a "glossy surface". For example, the smooth surface includes a surface with a very small degree of unevenness that does not correspond to the uneven surface.

In the substrate, only one surface may be an uneven surface, or both surfaces may be an uneven surface, but it is preferable that only one surface is an uneven surface. In other words, it is preferable that only one surface of the base material is a smooth surface. In the support sheet, the uneven surface of the substrate is the surface on which the pressure-sensitive adhesive layer is provided.

The substrate may consist of one layer (single layer), or may consist of a plurality of layers of two or more layers. A combination of layers is not particularly limited.
When the substrate consists of multiple layers, the surface of the outermost layer of these multiple layers (the surface closest to the adhesive layer, or both the surface closest to and farthest from the adhesive layer) has the unevenness. face.

In the present specification, not only in the case of the substrate, "multiple layers may be the same or different" means "all the layers may be the same or all the layers may be different. may be the same, or only some of the layers may be the same", and further, "the plurality of layers are different from each other" means that "at least one of the constituent materials and thickness of each layer is different from each other". do.

The maximum height roughness (Rz) measured in accordance with JIS B 0601: 2013 on the uneven surface (first surface) of the substrate provided with the adhesive layer is 0.01 to 8 μm. It is preferably 0.1 to 7 μm, particularly preferably 0.5 to 6 μm. When the Rz of the base material is equal to or higher than the lower limit value, the occurrence of defects when the base material is independently wound into a roll and fed out is suppressed. Furthermore, in the manufacturing process of the support sheet or the composite sheet for forming a protective film, the laminate containing the base material is similarly prevented from causing problems during winding and unwinding. On the other hand, when the Rz of the substrate is equal to or less than the upper limit, the lamination property of the adhesive layer and the protective film-forming film, and the printing visibility of the protective film or the protective film-forming film through the support sheet Both properties are improved.

When both surfaces of the substrate are uneven surfaces, the degree of unevenness on both surfaces may be the same or different.

Examples of the constituent material of the base material include various resins.
Examples of the resin include polyethylenes such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and high-density polyethylene (HDPE); Polyolefin; ethylene-based copolymers such as ethylene-vinyl acetate copolymer, ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylic acid ester copolymer, ethylene-norbornene copolymer (ethylene Polyvinyl chloride resins such as polyvinyl chloride and vinyl chloride copolymers (resins obtained using vinyl chloride as a monomer); Polystyrene; Polycycloolefin; Polyethylene terephthalate, polyethylene Polyesters such as naphthalate, polybutylene terephthalate, polyethylene isophthalate, polyethylene-2,6-naphthalenedicarboxylate, and wholly aromatic polyesters in which all constituent units have aromatic cyclic groups; Poly(meth)acrylate; Polyurethane; Polyurethane acrylate; Polyimide; Polyamide; Polycarbonate; Fluororesin;
Examples of the resin include polymer alloys such as mixtures of the polyester and other resins. The polymer alloy of the polyester and the resin other than polyester is preferably one in which the amount of the resin other than the polyester is relatively small.
Further, as the resin, for example, a crosslinked resin in which one or more of the resins exemplified above are crosslinked; Also included are resins.

As used herein, "(meth)acrylic acid" is a concept that includes both "acrylic acid" and "methacrylic acid". The same applies to terms similar to (meth) acrylic acid. For example, "(meth) acryloyl group" is a concept that includes both "acryloyl group" and "methacryloyl group", and "(meth) acrylate ” is a concept that includes both “acrylate” and “methacrylate”.

The resin constituting the substrate may be of one type or two or more types, and when two or more types are used, the combination and ratio thereof can be arbitrarily selected.

The thickness of the substrate is preferably in the range of 50-300 μm, more preferably in the range of 60-150 μm. When the thickness of the substrate is within such a range, the flexibility of the protective film-forming composite sheet and the adhesion to a semiconductor wafer or a semiconductor chip are further improved.
Since the substrate has an uneven surface as described above, the thickness varies depending on the part of the substrate. Therefore, the minimum thickness of the substrate may be equal to or greater than the lower limit, and the maximum thickness of the substrate may be equal to or less than the upper limit.
The "thickness of the base material" means the thickness of the entire base material. For example, the thickness of the base material consisting of multiple layers means the total thickness of all layers constituting the base material. do.

The thickness of the substrate can be measured, for example, by observing the side or cross section of the substrate using a scanning electron microscope (SEM).
The cross section of the base material can be formed, for example, by the same method as in the case of the cross section of the test piece of the support sheet and protective film-forming composite sheet described above.

For example, by the method described above, a test piece is cut out from a plurality of locations (for example, 5 locations) of the support sheet or protective film-forming composite sheet, and the minimum and maximum values of the thickness of the substrate are obtained in this test piece. Further, when the average value of the minimum values and the average value of the maximum values are obtained from these values, the average value of the minimum values may be equal to or greater than the lower limit value of the thickness of the base material, and the maximum The average value of the values may be equal to or less than the above upper limit of the thickness of the substrate.

The substrate contains various known additives such as fillers, colorants, antistatic agents, antioxidants, organic lubricants, catalysts, softeners (plasticizers), etc., in addition to the main constituent materials such as the resins. may

The substrate is preferably transparent.
The base material may be colored according to the purpose, and other layers may be vapor-deposited thereon.
For example, when the protective film-forming film is energy ray-curable, the substrate is preferably permeable to energy rays.

In order to improve the adhesion of the base material to a layer that is in direct contact, such as an adhesive layer provided thereon, the base material is subjected to corona discharge treatment, electron beam irradiation treatment, plasma treatment, ozone/ultraviolet irradiation treatment, flame treatment, The surface may be subjected to oxidation treatment such as chromic acid treatment or hot air treatment.
Further, the substrate may have a primer-treated surface.
In addition, the base material has an antistatic coating layer; prevents the base material from adhering to other sheets and the base material from adhering to the adsorption table when the composite sheet for forming a protective film is superimposed and stored. It may have layers or the like.

A base material can be manufactured by a well-known method. For example, a substrate containing a resin can be produced by molding a resin composition containing the resin.

When using a base material that does not have an uneven surface (in other words, a base material having smooth surfaces on both sides), the smooth surface of the base material may be subjected to an uneven surface treatment.
The roughening treatment can be performed by a known method. For example, by using a metal roll or metal plate having an uneven surface and pressing the uneven surface against the smooth surface of the substrate, the smooth surface of the substrate can be unevenly processed. At this time, it is preferable to press a heated metal roll or metal plate against the smooth surface of the substrate. Further, the smooth surface of the base material can be roughened by sandblasting, solvent treatment, or the like.

O Adhesive Layer The adhesive layer is in the form of a sheet or a film.
In the pressure-sensitive adhesive layer, usually, regardless of the presence or absence of an intermediate layer between the substrate and the pressure-sensitive adhesive layer, at least the surface on the substrate side becomes an uneven surface under the influence of the uneven surface of the substrate. ing.

The pressure-sensitive adhesive layer may consist of one layer (single layer) or may consist of two or more layers. The combination of multiple layers is not particularly limited.
When the pressure-sensitive adhesive layer is composed of multiple layers, the surface of the outermost layer (the surface closest to the substrate) among these multiple layers is the uneven surface.

Here, the base material and the pressure-sensitive adhesive layer will be described in more detail with reference to the drawings.
FIG. 4 is an enlarged cross-sectional view schematically showing a protective film-forming composite sheet according to one embodiment of the present invention. Here, the protective film-forming composite sheet 1A shown in FIG. 1 will be described as an example. In addition, illustration of the peeling film is omitted in FIG.

As described above, the first surface 11a of the substrate 11 is an uneven surface. The adhesive layer 12 is provided in direct contact with the first surface (uneven surface) 11a of the substrate 11, and the second surface 12b of the adhesive layer 12 is provided on the first surface 11a of the substrate 11. easier to follow. Therefore, the second surface 12b of the adhesive layer 12 also becomes an uneven surface.

The thickness _Ta of the pressure-sensitive adhesive layer 12 is not constant and varies depending on the portion of the pressure-sensitive adhesive layer 12 . Here, the minimum value of the thickness of the adhesive layer 12 is denoted by symbol _Ta1 , and the maximum value of the thickness of the adhesive layer 12 is denoted by symbol _Ta2 .

In the protective film-forming composite sheet 1A, test pieces were cut out from five locations, cross sections were formed in these five test pieces, and the thickness of the pressure-sensitive adhesive layer was measured in each of the newly formed cross sections. A minimum value T _a1 and a maximum value T _a2 are determined. Then, when the average value (said S value) is obtained from at least five _Ta1 values, it is 1.5 μm or more, and when the average value (said L value) is obtained from at least five _Ta2 values, it is 9 μm. It is as follows.

Cutting out a test piece from the protective film-forming composite sheet 1A, forming a cross section in the test piece, and measuring the minimum value _Ta1 and the maximum value _Ta2 of the thickness of the pressure-sensitive adhesive layer in the cross section are performed as described above. As described above, it can be carried out in the same manner as in the case where a test piece is cut out from a support sheet that does not constitute a composite sheet for forming a protective film.

The enlarged cross-sectional view of the supporting sheet that does not constitute the composite sheet for forming a protective film is the same as that of FIG.

Here, as the protective film-forming composite sheet 1A, between the base material 11 and the pressure-sensitive adhesive layer 12, there is a region where they are not bonded (in this specification, it may be referred to as a "non-bonded region"). ) 91 is present. However, even if the protective film-forming composite sheet 1A has such a non-bonding region 91, the size of the non-bonding region 91 in the thickness direction of the protective film-forming composite sheet 1A may be, for example, , 0.5 μm or less, the protective film-forming composite sheet 1A has good lamination properties between the substrate 11 and the pressure-sensitive adhesive layer 12, and can be said to have good properties.

In the present specification, "the size of the non-bonded region in the thickness direction of the protective film-forming composite sheet" means "two adjacent layers in the protective film-forming composite sheet, the thickness of the sheet It means "interlayer distance in the direction" and is sometimes simply referred to as "interlayer distance". For example, the above-mentioned "the size of the non-bonding region 91 in the thickness direction of the protective film-forming composite sheet 1A" means "the size of the substrate 11 and the pressure-sensitive adhesive layer 12 in the thickness direction of the sheet 1A. means "interlayer distance".
When the size (interlayer distance) of one non-bonded area varies, the maximum value is adopted as the size (interlayer distance) of the non-bonded area.

The size of the non-bonded region (interlayer distance) can be measured, for example, by the same method as for the thickness of the pressure-sensitive adhesive layer described above. That is, a cross section is formed in a test piece of the protective film-forming composite sheet in the same manner as in determining the thickness of the pressure-sensitive adhesive layer, and the size of the non-bonded region can be determined in this cross section. Alternatively, without preparing a test piece, a cross section may be formed with the protective film-forming composite sheet itself, and the size of the non-bonded region may be obtained in this cross section.

The size of the non-bonding region 91 (the interlayer distance) may be, for example, any one of 0.4 μm or less, 0.3 μm or less, 0.2 μm or less, and 0.1 μm or less.

In the protective film-forming composite sheet 1A, the non-bonding region 91 may not exist at all.

Here, the protective film-forming composite sheet 1A was taken as an example to describe the substrate and the adhesive layer. Also in the case of the composite sheet for forming a protective film, the base material and the pressure-sensitive adhesive layer are the same.

The S value of the pressure-sensitive adhesive layer is not particularly limited as long as it is 1.5 μm or more and less than 9 μm, but is preferably 1.7 μm or more, more preferably 1.9 μm or more. Any of 2.3 μm or more, 2.7 μm or more, 3.1 μm or more, and 3.5 μm or more may be used. When the S value is equal to or higher than the lower limit, the lamination property between the pressure-sensitive adhesive layer and the film for forming a protective film is further improved.

On the other hand, the S value of the adhesive layer may be, for example, 8 μm or less. Such an adhesive layer can be formed more easily.

The S value of the pressure-sensitive adhesive layer can be appropriately adjusted within a range set by arbitrarily combining the preferred lower and upper limits described above. For example, the S value of the pressure-sensitive adhesive layer is preferably 1.5 to 8 μm, more preferably 1.7 to 8 μm, still more preferably 1.9 to 8 μm. 8 μm, 3.1-8 μm, and 3.5-8 μm. However, these are examples of the S value of the pressure-sensitive adhesive layer.

The L value of the pressure-sensitive adhesive layer is not particularly limited as long as it is 9 μm or less and greater than 1.5 μm, but is preferably 8.6 μm or less, more preferably 8.3 μm or less. It may be any one of 7.7 μm or less, 7.3 μm or less, 6.9 μm or less, and 6.5 μm or less. When the L value is equal to or less than the upper limit, the print visibility of the protective film or protective film-forming film through the support sheet becomes better.

On the other hand, the L value of the adhesive layer may be, for example, 2.5 μm or more. Such an adhesive layer can be formed more easily.

The L value of the pressure-sensitive adhesive layer can be appropriately adjusted within a range set by arbitrarily combining the preferred lower and upper limits described above. For example, the L value of the adhesive layer is preferably 2.5-9 μm, more preferably 2.5-8.6 μm, still more preferably 2.5-8.3 μm, for example, 2.5-7. 7 μm, 2.5-7.3 μm, 2.5-6.9 μm, and 2.5-6.5 μm.

The thickness (for example, T _a ) of the pressure-sensitive adhesive layer is not particularly limited as long as the conditions for the S value and L value described above are satisfied.
For example, the thickness of the adhesive layer may be 1.5-9 μm.

In addition, the "thickness of the adhesive layer" means the thickness of the entire adhesive layer. means thickness. From this point of view, the minimum and maximum values of the thickness of the pressure-sensitive adhesive layer are defined.

The adhesive layer contains an adhesive.
Examples of the adhesive include adhesive resins such as acrylic resins, urethane resins, rubber resins, silicone resins, epoxy resins, polyvinyl ethers, polycarbonates, and ester resins, with acrylic resins being preferred. .

As used herein, the term "adhesive resin" is a concept that includes both a resin having adhesiveness and a resin having adhesiveness. It also includes resins that exhibit adhesiveness when used in combination with other components such as agents, and resins that exhibit adhesiveness due to the presence of a trigger such as heat or water.

The adhesive layer is preferably transparent.
The pressure-sensitive adhesive layer may be colored depending on the purpose.
For example, when the protective film-forming film is energy ray-curable, the pressure-sensitive adhesive layer is preferably permeable to energy rays.

The adhesive layer may be formed using an energy ray-curable adhesive, or may be formed using a non-energy ray-curable adhesive. A pressure-sensitive adhesive layer formed using an energy ray-curable pressure-sensitive adhesive can easily adjust physical properties before and after curing.

<<Adhesive Composition>>
The adhesive layer can be formed using an adhesive composition containing an adhesive. For example, the pressure-sensitive adhesive layer can be formed on the target site by applying the pressure-sensitive adhesive composition to the surface on which the pressure-sensitive adhesive layer is to be formed, and drying it as necessary. A more specific method for forming the pressure-sensitive adhesive layer will be described later in detail together with methods for forming other layers. The content ratio of the components that do not vaporize at room temperature in the pressure-sensitive adhesive composition is usually the same as the content ratio of the components in the pressure-sensitive adhesive layer.

As used herein, the term "ordinary temperature" means a temperature that is not particularly cooled or heated, that is, a normal temperature.

Coating of the pressure-sensitive adhesive composition may be performed by a known method, for example, air knife coater, blade coater, bar coater, gravure coater, roll coater, roll knife coater, curtain coater, die coater, knife coater, screen coater. , Meyer bar coater, kiss coater and the like.

Drying conditions for the pressure-sensitive adhesive composition are not particularly limited, but when the pressure-sensitive adhesive composition contains a solvent to be described later, it is preferable to dry by heating. The solvent-containing pressure-sensitive adhesive composition is preferably dried, for example, at 70 to 130° C. for 10 seconds to 5 minutes.

When the pressure-sensitive adhesive layer is energy-ray-curable, the pressure-sensitive adhesive composition containing the energy-ray-curable pressure-sensitive adhesive, i.e., the energy-ray-curable pressure-sensitive adhesive composition includes, for example, non-energy-ray-curable pressure-sensitive adhesive Adhesive composition (I-1) containing a resin (I-1a) (hereinafter sometimes abbreviated as "adhesive resin (I-1a)") and an energy ray-curable compound; non-energy An energy ray-curable adhesive resin (I-2a) in which an unsaturated group is introduced into the side chain of the radiation-curable adhesive resin (I-1a) (hereinafter referred to as “adhesive resin (I-2a)”) a pressure-sensitive adhesive composition (I-2) containing the adhesive resin (I-2a); and a pressure-sensitive adhesive composition (I-3) containing the adhesive resin (I-2a) and an energy ray-curable compound, etc. is mentioned.

<Adhesive composition (I-1)>
The adhesive composition (I-1) contains, as described above, a non-energy ray-curable adhesive resin (I-1a) and an energy ray-curable compound.

[Adhesive resin (I-1a)]
The adhesive resin (I-1a) is preferably an acrylic resin.
Examples of the acrylic resin include an acrylic polymer having at least a structural unit derived from a (meth)acrylic acid alkyl ester.
The structural units of the acrylic resin may be of one type or two or more types, and when there are two or more types, the combination and ratio thereof can be arbitrarily selected.

Examples of the (meth)acrylic acid alkyl ester include those in which the alkyl group constituting the alkyl ester has 1 to 20 carbon atoms, and the alkyl group is linear or branched. is preferred.
(Meth)acrylic acid alkyl esters, more specifically, methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, (meth)acrylic acid n-butyl, 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, n-octyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, (meth) ) undecyl acrylate, dodecyl (meth) acrylate (lauryl (meth) acrylate), tridecyl (meth) acrylate, tetradecyl (meth) acrylate (myristyl (meth) acrylate), pentadecyl (meth) acrylate, ( Hexadecyl methacrylate (palmityl (meth)acrylate), heptadecyl (meth)acrylate, octadecyl (meth)acrylate (stearyl (meth)acrylate), nonadecyl (meth)acrylate, icosyl (meth)acrylate, etc. is mentioned.

From the viewpoint of improving the adhesive strength of the pressure-sensitive adhesive layer, the acrylic polymer preferably has a structural unit derived from a (meth)acrylic acid alkyl ester in which the alkyl group has 4 or more carbon atoms. The number of carbon atoms in the alkyl group is preferably 4 to 12, more preferably 4 to 8, from the viewpoint of further improving the adhesive strength of the adhesive layer. In addition, the (meth)acrylic acid alkyl ester in which the alkyl group has 4 or more carbon atoms is preferably an acrylic acid alkyl ester.

It is preferable that the acrylic polymer further has a structural unit derived from a functional group-containing monomer in addition to the structural unit derived from the (meth)acrylic acid alkyl ester.
As the functional group-containing monomer, for example, the functional group reacts with a cross-linking agent described later to become a starting point for cross-linking, or the functional group reacts with an unsaturated group in the unsaturated group-containing compound described later. and those capable of introducing an unsaturated group into the side chain of the acrylic polymer.

Examples of the functional group in the functional group-containing monomer include hydroxyl group, carboxyl group, amino group, epoxy group and the like.
That is, examples of functional group-containing monomers include hydroxyl group-containing monomers, carboxy group-containing monomers, amino group-containing monomers, and epoxy group-containing monomers.

Examples of the hydroxyl group-containing monomer include hydroxymethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, (meth) Hydroxyalkyl (meth)acrylates such as 2-hydroxybutyl acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; Saturated alcohol (unsaturated alcohol having no (meth)acryloyl skeleton) and the like can be mentioned.

Examples of the carboxy group-containing monomer include ethylenically unsaturated monocarboxylic acids (monocarboxylic acids having an ethylenically unsaturated bond) such as (meth)acrylic acid and crotonic acid; fumaric acid, itaconic acid, maleic acid, citracone; ethylenically unsaturated dicarboxylic acids (dicarboxylic acids having an ethylenically unsaturated bond) such as acids; anhydrides of the ethylenically unsaturated dicarboxylic acids; (meth)acrylic acid carboxyalkyl esters such as 2-carboxyethyl methacrylate; be done.

The functional group-containing monomer is preferably a hydroxyl group-containing monomer or a carboxy group-containing monomer, more preferably a hydroxyl group-containing monomer.

The functional group-containing monomers constituting the acrylic polymer may be of one type or two or more types, and when two or more types are used, the combination and ratio thereof can be arbitrarily selected.

In the acrylic polymer, the content of structural units derived from functional group-containing monomers is preferably 1 to 35% by mass, more preferably 2 to 30% by mass, based on the total amount of structural units. , 3 to 27% by weight.

The acrylic polymer may further have structural units derived from other monomers in addition to the structural units derived from the (meth)acrylic acid alkyl ester and the structural units derived from the functional group-containing monomer.
The other monomer is not particularly limited as long as it is copolymerizable with (meth)acrylic acid alkyl ester or the like.
Examples of the other monomers include styrene, α-methylstyrene, vinyltoluene, vinyl formate, vinyl acetate, acrylonitrile and acrylamide.

The other monomers constituting the acrylic polymer may be of one type or two or more types, and when there are two or more types, the combination and ratio thereof can be arbitrarily selected.

The acrylic polymer can be used as the above non-energy ray-curable adhesive resin (I-1a).
On the other hand, the functional group in the acrylic polymer is reacted with an unsaturated group-containing compound having an energy ray-polymerizable unsaturated group (energy ray-polymerizable group), and the above-mentioned energy ray-curable adhesiveness It can be used as resin (I-2a).

The pressure-sensitive adhesive resin (I-1a) contained in the pressure-sensitive adhesive composition (I-1) may be of only one type, or may be of two or more types. You can choose.

In the adhesive composition (I-1), the content of the adhesive resin (I-1a) is preferably 5 to 99% by mass with respect to the total mass of the adhesive composition (I-1), It is more preferably 10 to 95% by mass, particularly preferably 15 to 90% by mass.

[Energy ray-curable compound]
Examples of the energy ray-curable compound contained in the pressure-sensitive adhesive composition (I-1) include monomers or oligomers having energy ray-polymerizable unsaturated groups and curable by energy ray irradiation.
Among energy ray-curable compounds, monomers include, for example, trimethylolpropane tri(meth)acrylate, pentaerythritol (meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,4 -polyvalent (meth)acrylates such as butylene glycol di(meth)acrylate, 1,6-hexanediol (meth)acrylate; urethane (meth)acrylates; polyester (meth)acrylates; polyether (meth)acrylates; meth)acrylate and the like.
Among energy ray-curable compounds, oligomers include, for example, oligomers obtained by polymerizing the above-exemplified monomers.
Urethane (meth)acrylates and urethane (meth)acrylate oligomers are preferred as the energy ray-curable compound because they have a relatively large molecular weight and are unlikely to reduce the storage modulus of the pressure-sensitive adhesive layer.

The energy ray-curable compound contained in the pressure-sensitive adhesive composition (I-1) may be of one type or two or more types, and when there are two or more types, the combination and ratio thereof can be arbitrarily selected. .

In the pressure-sensitive adhesive composition (I-1), the content of the energy ray-curable compound is preferably 1 to 95% by mass with respect to the total weight of the pressure-sensitive adhesive composition (I-1). It is more preferably 90 mass %, particularly preferably 10 to 85 mass %.

[Crosslinking agent]
As the adhesive resin (I-1a), in addition to the structural unit derived from the (meth)acrylic acid alkyl ester, when using the acrylic polymer having a structural unit derived from a functional group-containing monomer, the adhesive composition ( I-1) preferably further contains a cross-linking agent.

The cross-linking agent is, for example, one that reacts with the functional group to cross-link the adhesive resins (I-1a).
Examples of cross-linking agents include tolylene diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, isocyanate-based cross-linking agents (cross-linking agents having isocyanate groups) such as adducts of these diisocyanates; epoxy-based cross-linking agents such as ethylene glycol glycidyl ether ( aziridinyl cross-linking agents such as hexa[1-(2-methyl)-aziridinyl]triphosphatriazine (cross-linking agents having an aziridinyl group); metal chelate cross-linking agents such as aluminum chelate (metal cross-linking agents having a chelate structure); isocyanurate-based cross-linking agents (cross-linking agents having an isocyanuric acid skeleton);
The cross-linking agent is preferably an isocyanate-based cross-linking agent because it improves the cohesive force of the pressure-sensitive adhesive to improve the adhesive strength of the pressure-sensitive adhesive layer and is easily available.

The pressure-sensitive adhesive composition (I-1) may contain one type of cross-linking agent, or two or more types thereof.

In the adhesive composition (I-1), the content of the cross-linking agent is preferably 0.01 to 50 parts by mass with respect to 100 parts by mass of the content of the adhesive resin (I-1a), It is more preferably 0.1 to 20 parts by mass, particularly preferably 0.3 to 15 parts by mass.

[Photoinitiator]
The adhesive composition (I-1) may further contain a photopolymerization initiator. The adhesive composition (I-1) containing a photopolymerization initiator undergoes a sufficient curing reaction even when irradiated with relatively low-energy energy rays such as ultraviolet rays.

Examples of the photopolymerization initiator include benzoin compounds such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin benzoic acid, benzoin methyl benzoate, and benzoin dimethyl ketal; acetophenone, 2-hydroxy -Acetophenone compounds such as 2-methyl-1-phenyl-propan-1-one and 2,2-dimethoxy-1,2-diphenylethan-1-one; bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, acylphosphine oxide compounds such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide; sulfide compounds such as benzylphenyl sulfide and tetramethylthiuram monosulfide; α-ketol compounds such as 1-hydroxycyclohexylphenyl ketone; azo compounds such as bisisobutyronitrile; titanocene compounds such as titanocene; thioxanthone compounds such as thioxanthone; peroxide compounds; diketone compounds such as diacetyl; 2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone; 2-chloroanthraquinone and the like.
As the photopolymerization initiator, for example, a quinone compound such as 1-chloroanthraquinone; a photosensitizer such as an amine;

The photopolymerization initiator contained in the pressure-sensitive adhesive composition (I-1) may be of one type or two or more types, and when two or more types are used, the combination and ratio thereof can be arbitrarily selected.

In the adhesive composition (I-1), the content of the photopolymerization initiator is preferably 0.01 to 20 parts by mass with respect to 100 parts by mass of the energy ray-curable compound. It is more preferably from 0.03 to 10 parts by mass, and particularly preferably from 0.05 to 5 parts by mass.

[Other additives]
The pressure-sensitive adhesive composition (I-1) may contain other additives that do not fall under any of the above-described components, as long as they do not impair the effects of the present invention.
Examples of other additives include antistatic agents, antioxidants, softeners (plasticizers), fillers, rust inhibitors, colorants (pigments, dyes), sensitizers, and tackifiers. , a reaction retardant, a cross-linking accelerator (catalyst), and other known additives.
The reaction retarder is, for example, an unintended cross-linking reaction in the PSA composition (I-1) during storage due to the action of a catalyst mixed in the PSA composition (I-1). It suppresses progression. Examples of the reaction retarder include those that form a chelate complex by chelating the catalyst, more specifically those having two or more carbonyl groups (-C(=O)-) in one molecule. mentioned.

The other additives contained in the pressure-sensitive adhesive composition (I-1) may be of one type or two or more types, and when two or more types are used, their combination and ratio can be arbitrarily selected.

The content of other additives in the pressure-sensitive adhesive composition (I-1) is not particularly limited, and may be appropriately selected according to the type.

[solvent]
The adhesive composition (I-1) may contain a solvent. Since the pressure-sensitive adhesive composition (I-1) contains a solvent, the coating suitability to the surface to be coated is improved.

The solvent is preferably an organic solvent, and examples of the organic solvent include ketones such as methyl ethyl ketone and acetone; esters (carboxylic acid esters) such as ethyl acetate; ethers such as tetrahydrofuran and dioxane; cyclohexane, n-hexane, and the like. aromatic hydrocarbons such as toluene and xylene; alcohols such as 1-propanol and 2-propanol.

As the solvent, for example, the solvent used in the production of the adhesive resin (I-1a) may be used as it is in the adhesive composition (I-1) without removing it from the adhesive resin (I-1a). However, a solvent of the same or different type as that used in the production of the adhesive resin (I-1a) may be added separately in the production of the adhesive composition (I-1).

The pressure-sensitive adhesive composition (I-1) may contain only one kind of solvent, or two or more kinds of solvents.

In the pressure-sensitive adhesive composition (I-1), the solvent content is not particularly limited and may be adjusted as appropriate.

<Adhesive composition (I-2)>
As described above, the pressure-sensitive adhesive composition (I-2) is an energy-ray-curable adhesive resin in which an unsaturated group is introduced into the side chain of the non-energy-ray-curable adhesive resin (I-1a). Contains (I-2a).

[Adhesive resin (I-2a)]
The adhesive resin (I-2a) is obtained, for example, by reacting a functional group in the adhesive resin (I-1a) with an unsaturated group-containing compound having an energy ray-polymerizable unsaturated group.

The unsaturated group-containing compound is capable of bonding with the adhesive resin (I-1a) by reacting with a functional group in the adhesive resin (I-1a) in addition to the energy ray-polymerizable unsaturated group. It is a compound having a group.
Examples of the energy ray polymerizable unsaturated group include (meth)acryloyl group, vinyl group (ethenyl group), allyl group (2-propenyl group) and the like, and (meth)acryloyl group is preferred.
Groups capable of bonding with functional groups in the adhesive resin (I-1a) include, for example, an isocyanate group and a glycidyl group capable of bonding with a hydroxyl group or an amino group, and a hydroxyl group and an amino group capable of bonding with a carboxy group or an epoxy group. etc.

Examples of the unsaturated group-containing compound include (meth)acryloyloxyethyl isocyanate, (meth)acryloylisocyanate, glycidyl (meth)acrylate, and the like.

The pressure-sensitive adhesive resin (I-2a) contained in the pressure-sensitive adhesive composition (I-2) may be of only one type, or may be of two or more types. You can choose.

In the adhesive composition (I-2), the content of the adhesive resin (I-2a) is preferably 5 to 99% by mass with respect to the total mass of the adhesive composition (I-2), It is more preferably 10 to 95% by mass, particularly preferably 10 to 90% by mass.

[Crosslinking agent]
As the adhesive resin (I-2a), for example, when using the acrylic polymer having the same structural unit derived from a functional group-containing monomer as in the adhesive resin (I-1a), the adhesive composition ( I-2) may further contain a cross-linking agent.

Examples of the cross-linking agent in the pressure-sensitive adhesive composition (I-2) include the same cross-linking agents as in the pressure-sensitive adhesive composition (I-1).
The pressure-sensitive adhesive composition (I-2) may contain one type of cross-linking agent, or two or more types thereof.

In the adhesive composition (I-2), the content of the cross-linking agent is preferably 0.01 to 50 parts by mass with respect to 100 parts by mass of the content of the adhesive resin (I-2a), It is more preferably 0.1 to 20 parts by mass, particularly preferably 0.3 to 15 parts by mass.

[Photoinitiator]
The adhesive composition (I-2) may further contain a photopolymerization initiator. The adhesive composition (I-2) containing a photopolymerization initiator undergoes a sufficient curing reaction even when irradiated with relatively low-energy energy rays such as ultraviolet rays.

Examples of the photopolymerization initiator in the pressure-sensitive adhesive composition (I-2) include the same photopolymerization initiators as in the pressure-sensitive adhesive composition (I-1).
The photopolymerization initiator contained in the pressure-sensitive adhesive composition (I-2) may be of one type or two or more types, and when two or more types are used, the combination and ratio thereof can be arbitrarily selected.

In the adhesive composition (I-2), the content of the photopolymerization initiator is preferably 0.01 to 20 parts by mass with respect to 100 parts by mass of the adhesive resin (I-2a). , more preferably 0.03 to 10 parts by mass, particularly preferably 0.05 to 5 parts by mass.

[Other additives]
The pressure-sensitive adhesive composition (I-2) may contain other additives that do not fall under any of the above-mentioned components, as long as they do not impair the effects of the present invention.
Examples of the other additives in the adhesive composition (I-2) include the same additives as the other additives in the adhesive composition (I-1).
The other additives contained in the pressure-sensitive adhesive composition (I-2) may be of one type or two or more types, and when there are two or more types, their combination and ratio can be arbitrarily selected.

The content of other additives in the pressure-sensitive adhesive composition (I-2) is not particularly limited, and may be appropriately selected according to the type.

[solvent]
The adhesive composition (I-2) may contain a solvent for the same purpose as the adhesive composition (I-1).
Examples of the solvent in the adhesive composition (I-2) include the same solvents as in the adhesive composition (I-1).
The pressure-sensitive adhesive composition (I-2) may contain only one kind of solvent, or two or more kinds of solvents.
In the pressure-sensitive adhesive composition (I-2), the solvent content is not particularly limited and may be adjusted as appropriate.

<Adhesive composition (I-3)>
The adhesive composition (I-3) contains the adhesive resin (I-2a) and an energy ray-curable compound, as described above.

In the adhesive composition (I-3), the content of the adhesive resin (I-2a) is preferably 5 to 99% by mass with respect to the total mass of the adhesive composition (I-3), It is more preferably 10 to 95% by mass, particularly preferably 15 to 90% by mass.

[Energy ray-curable compound]
Examples of the energy ray-curable compound contained in the pressure-sensitive adhesive composition (I-3) include monomers and oligomers that have an energy-ray-polymerizable unsaturated group and can be cured by irradiation with an energy ray. The same energy ray-curable compound contained in the product (I-1) can be mentioned.
The energy ray-curable compound contained in the pressure-sensitive adhesive composition (I-3) may be of one type or two or more types, and when there are two or more types, the combination and ratio thereof can be arbitrarily selected. .

In the adhesive composition (I-3), the content of the energy ray-curable compound is 0.01 to 300 parts by mass with respect to 100 parts by mass of the adhesive resin (I-2a). preferably 0.03 to 200 parts by mass, particularly preferably 0.05 to 100 parts by mass.

[Photoinitiator]
The adhesive composition (I-3) may further contain a photopolymerization initiator. The adhesive composition (I-3) containing a photopolymerization initiator undergoes a sufficient curing reaction even when irradiated with relatively low-energy energy rays such as ultraviolet rays.

Examples of the photopolymerization initiator in the pressure-sensitive adhesive composition (I-3) include the same photopolymerization initiators as in the pressure-sensitive adhesive composition (I-1).
The photopolymerization initiator contained in the pressure-sensitive adhesive composition (I-3) may be of one type or two or more types, and when two or more types are used, the combination and ratio thereof can be arbitrarily selected.

In the adhesive composition (I-3), the content of the photopolymerization initiator is 0.01 to 0.01 with respect to 100 parts by mass of the total content of the adhesive resin (I-2a) and the energy ray-curable compound. It is preferably 20 parts by mass, more preferably 0.03 to 10 parts by mass, and particularly preferably 0.05 to 5 parts by mass.

[Other additives]
The pressure-sensitive adhesive composition (I-3) may contain other additives that do not fall under any of the above-mentioned components, as long as they do not impair the effects of the present invention.
Examples of the other additives include the same as the other additives in the adhesive composition (I-1).
The other additives contained in the pressure-sensitive adhesive composition (I-3) may be of one type or two or more types, and when two or more types are used, their combination and ratio can be selected arbitrarily.

In the pressure-sensitive adhesive composition (I-3), the content of other additives is not particularly limited, and may be appropriately selected according to the type.

[solvent]
The adhesive composition (I-3) may contain a solvent for the same purpose as the adhesive composition (I-1).
Examples of the solvent in the adhesive composition (I-3) include the same solvents as in the adhesive composition (I-1).
The pressure-sensitive adhesive composition (I-3) may contain only one kind of solvent, or two or more kinds of solvents.
In the pressure-sensitive adhesive composition (I-3), the solvent content is not particularly limited and may be adjusted as appropriate.

<Adhesive Compositions Other than Adhesive Compositions (I-1) to (I-3)>
So far, the adhesive composition (I-1), the adhesive composition (I-2) and the adhesive composition (I-3) have been mainly described, but the components described as these components are A general adhesive composition other than these three adhesive compositions (herein referred to as "adhesive compositions other than adhesive compositions (I-1) to (I-3)") But you can use it as well.

The pressure-sensitive adhesive compositions other than the pressure-sensitive adhesive compositions (I-1) to (I-3) include not only energy-ray-curable pressure-sensitive adhesive compositions but also non-energy-ray-curable pressure-sensitive adhesive compositions.
Non-energy ray-curable adhesive compositions include, for example, non-energy ray-curable acrylic resins, urethane-based resins, rubber-based resins, silicone-based resins, epoxy-based resins, polyvinyl ethers, polycarbonates, ester-based resins, and the like. adhesive composition (I-4) containing a flexible adhesive resin (I-1a), and those containing an acrylic resin are preferred.

The pressure-sensitive adhesive compositions other than the pressure-sensitive adhesive compositions (I-1) to (I-3) preferably contain one or more cross-linking agents, the content of which is the same as the pressure-sensitive adhesive composition described above. It can be the same as the case of (I-1) or the like.

<Adhesive composition (I-4)>
Preferable examples of the adhesive composition (I-4) include those containing the adhesive resin (I-1a) and a cross-linking agent.

[Adhesive resin (I-1a)]
The adhesive resin (I-1a) in the adhesive composition (I-4) includes the same adhesive resin (I-1a) in the adhesive composition (I-1).
The pressure-sensitive adhesive resin (I-1a) contained in the pressure-sensitive adhesive composition (I-4) may be only one type, or may be two or more types, and when there are two or more types, the combination and ratio thereof are arbitrary You can choose.

In the adhesive composition (I-4), the content of the adhesive resin (I-1a) is preferably 5 to 99% by mass relative to the total mass of the adhesive composition (I-4), It is more preferably 10 to 95% by mass, particularly preferably 15 to 90% by mass.

In the adhesive composition (I-4), the ratio of the content of the adhesive resin (I-1a) to the total content of all components other than the solvent (i.e., the adhesive resin (I-1a) of the adhesive layer content) is preferably 30 to 90% by mass, more preferably 40 to 85% by mass, and particularly preferably 50 to 80% by mass.

[Crosslinking agent]
As the adhesive resin (I-1a), in addition to the structural unit derived from the (meth)acrylic acid alkyl ester, when using the acrylic polymer having a structural unit derived from a functional group-containing monomer, the adhesive composition ( I-4) preferably further contains a cross-linking agent.

Examples of the cross-linking agent in the pressure-sensitive adhesive composition (I-4) include the same cross-linking agents as in the pressure-sensitive adhesive composition (I-1).
The pressure-sensitive adhesive composition (I-4) may contain one type of cross-linking agent, or two or more types thereof.

In the adhesive composition (I-4), the content of the cross-linking agent is preferably 0.01 to 50 parts by mass with respect to 100 parts by mass of the content of the adhesive resin (I-1a), It is more preferably 0.3 to 50 parts by mass, more preferably 1 to 50 parts by mass, such as 10 to 50 parts by mass, 15 to 50 parts by mass, and 20 to 50 parts by mass. may be

[Other additives]
The pressure-sensitive adhesive composition (I-4) may contain other additives that do not fall under any of the above-described components, as long as they do not impair the effects of the present invention.
Examples of the other additives include the same as the other additives in the adhesive composition (I-1).
The other additives contained in the pressure-sensitive adhesive composition (I-4) may be of one type or two or more types, and when there are two or more types, their combination and ratio can be arbitrarily selected.

In the pressure-sensitive adhesive composition (I-4), the content of other additives is not particularly limited, and may be appropriately selected according to the type.

[solvent]
The adhesive composition (I-4) may contain a solvent for the same purpose as the adhesive composition (I-1).
Examples of the solvent in the adhesive composition (I-4) include the same solvents as in the adhesive composition (I-1).
The solvent contained in the pressure-sensitive adhesive composition (I-4) may be of one type or two or more types, and when two or more types are used, the combination and ratio thereof can be arbitrarily selected.
In the pressure-sensitive adhesive composition (I-4), the solvent content is not particularly limited and may be adjusted as appropriate.

In the protective film-forming composite sheet, the pressure-sensitive adhesive layer is preferably non-energy ray-curable. This is because if the pressure-sensitive adhesive layer is energy ray-curable, simultaneous curing of the pressure-sensitive adhesive layer may not be suppressed when the protective film-forming film is cured by irradiation with energy rays. If the pressure-sensitive adhesive layer is cured at the same time as the protective film-forming film, the protective film-forming film after curing (that is, the protective film) and the pressure-sensitive adhesive layer stick to each other at their interface to such an extent that they cannot be peeled off. There is In that case, it becomes difficult to peel off the protective film-forming film after curing, that is, the semiconductor chip having the protective film on the back surface (semiconductor chip with protective film) from the support sheet having the adhesive layer after curing, A semiconductor chip with a protective film cannot be normally picked up. By using a non-energy ray-curable adhesive layer in the support sheet, such problems can be reliably avoided, and the protective film-attached semiconductor chip can be picked up more easily.

Here, the effect in the case where the pressure-sensitive adhesive layer is non-energy ray-curable has been described. A similar effect can be obtained if the layer is non-energy ray curable.

<<Method for producing pressure-sensitive adhesive composition>>
Adhesive compositions other than the adhesive compositions (I-1) to (I-3) such as the adhesive compositions (I-1) to (I-3) and the adhesive composition (I-4) , the pressure-sensitive adhesive and, if necessary, each component for constituting the pressure-sensitive adhesive composition, such as components other than the pressure-sensitive adhesive.
There are no particular restrictions on the order of addition of each component when blending, and two or more components may be added at the same time.
When a solvent is used, the solvent may be mixed with any compounding component other than the solvent and used by diluting this compounding component in advance, or any compounding component other than the solvent may be diluted in advance. You may use by mixing a solvent with these compounding ingredients, without preserving.
The method of mixing each component at the time of blending is not particularly limited, and may be selected from known methods such as a method of mixing by rotating a stirrer or a stirring blade; a method of mixing using a mixer; a method of mixing by applying ultrasonic waves. It can be selected as appropriate.
The temperature and time at which each component is added and mixed are not particularly limited as long as each compounded component does not deteriorate, and may be adjusted as appropriate, but the temperature is preferably 15 to 30°C.

◎Film for forming a protective film The film for forming a protective film becomes a protective film by curing or as it is without being cured. This protective film is for protecting the back surface of the semiconductor wafer or semiconductor chip (the surface opposite to the electrode forming surface). The protective film-forming film is flexible and can be easily attached to an application target.

The protective film-forming film may be curable or non-curable.
The curable protective film-forming film may be either thermosetting or energy ray-curable, or may have both thermosetting and energy ray-curable properties.
The protective film-forming film can be formed using a protective film-forming composition containing its constituent materials.

As used herein, the term "non-curing" means the property of not being cured by any means such as heating or energy ray irradiation.
In the present invention, even after the protective film-forming film is cured, as long as the laminated structure of the support sheet and the cured product of the protective film-forming film (in other words, the support sheet and the protective film) is maintained. This laminate is called a "composite sheet for forming a protective film".

The protective film-forming film may consist of one layer (single layer) or may consist of two or more layers regardless of the type thereof. When the protective film-forming film consists of multiple layers, these multiple layers may be the same or different.

Here, the pressure-sensitive adhesive layer and the protective film-forming film will be described in more detail with reference to FIG. 4 again.
As described above, the first surface 11a of the substrate 11 is an uneven surface. However, in the pressure-sensitive adhesive layer 12, since the S value is 1.5 μm or more, the influence of this uneven surface is suppressed, and the degree of unevenness on the first surface 12a of the pressure-sensitive adhesive layer 12 is small. . Therefore, the lamination property between the pressure-sensitive adhesive layer 12 and the protective film-forming film 13 is improved. For example, even if there is an area (non-bonded area) 92 between the pressure-sensitive adhesive layer 12 and the protective film-forming film 13, the number thereof is Over the entire formation area of the film 13 for forming the inner protective film, the number is extremely small, such as 3 or less. The non-bonding region 92 can be easily confirmed by observing the protective film-forming composite sheet 1A from the substrate 11 side, for example.

Furthermore, even if the protective film-forming composite sheet 1A has such a non-bonding region 92, the size of the non-bonding region 92 in the thickness direction of the protective film-forming composite sheet 1A (interlayer distance ) is, for example, 0.5 μm or less, the adhesive layer 12 and the protective film-forming film 13 have better lamination properties. Here, the "size (interlayer distance) of the non-bonding region 92" means "the interlayer distance between the adhesive layer 12 and the protective film forming film 13 in the thickness direction of the protective film forming composite sheet 1A. means "distance".

The size of the non-bonding region 92 (interlayer distance) is preferably 0.5 μm or less, for example, 0.4 μm or less, like the interlayer distance (size) of the non-bonding region 91 described above. , 0.3 μm or less, 0.2 μm or less, or 0.1 μm or less.

The size (interlayer distance) of the non-bonded region 92 is determined by the same method as the size (interlayer distance) of the non-bonded region 91 described above, except that the combination of two layers to be targeted is different. be done.

In the protective film-forming composite sheet 1A, the non-bonding region 92 may not exist at all.

On the other hand, as described above, the unevenness of the first surface 12a of the adhesive layer 12 is small. Therefore, although the thickness _Tp of the protective film forming film 13 is not constant and varies depending on the portion of the protective film forming film 13 (adhesive layer 12), the fluctuation range is extremely small.

Furthermore, as described above, since the unevenness of the first surface 12a of the adhesive layer 12 is small, the surface (second surface) 13b of the protective film-forming film 13 on the adhesive layer 12 side is smooth. or the degree of unevenness is small. Therefore, the appearance of the protective film-forming film 13 is not damaged.
In addition, even in the protective film formed from the protective film-forming film 13, the surface (second surface) on the pressure-sensitive adhesive layer 12 side is smooth or less uneven, and the appearance of the protective film is spoiled. remain untouched.
Thus, in the protective film-forming composite sheet 1A, both the protective film-forming film 13 and the protective film can be excellent in design.

On the second surface 13b of the protective film-forming film 13, the maximum height difference between the highest portion of the convex portion and the deepest portion of the concave portion is preferably 2 μm or less, for example, 1.5 μm or less. and 1 μm or less. Such protective film-forming film 13 and protective film are particularly excellent in design.

The maximum height difference on the second surface 13b of the protective film-forming film 13 is obtained, for example, by forming a cross section in the test piece of the protective film-forming composite sheet or the protective film-forming composite sheet itself by the method described above, It is obtained by observing this cross section using a scanning electron microscope (SEM).

Here, the protective film-forming composite sheet 1A was taken as an example to describe the pressure-sensitive adhesive layer and the protective film-forming film. In the case of the protective film-forming composite sheet of the embodiment, the pressure-sensitive adhesive layer and the protective film-forming film are the same.

In the protective film-forming composite sheet of the present invention, the thickness (eg, T _p ) of the protective film-forming film is preferably 1 to 100 μm, more preferably 3 to 75 μm, and more preferably 5 to 50 μm. It is particularly preferred to have When the thickness of the film for forming a protective film is at least the lower limit, a protective film with higher protective ability can be formed. When the thickness of the protective film-forming film is equal to or less than the upper limit value, excessive thickness is suppressed.

When the thickness of the protective film-forming film varies depending on the part of the protective film-forming film, the minimum value of the thickness of the protective film-forming film may be the lower limit or more, and the protective film The maximum thickness of the forming film may be equal to or less than the upper limit.

In addition, the "thickness of the protective film-forming film" means the thickness of the entire protective film-forming film. It means the total thickness of all the constituent layers.

The thickness of the protective film-forming film can be measured, for example, by observing the side or cross section of the protective film-forming film using a scanning electron microscope (SEM).
The cross-section of the protective film-forming film can be formed, for example, by the same method as in the case of the cross-section of the test piece of the support sheet and protective film-forming composite sheet described above.

For example, by the method described above, a test piece is cut out from a plurality of locations (for example, 5 locations) of the composite sheet for forming a protective film, and in this test piece, the minimum and maximum values of the thickness of the film for forming a protective film are obtained. Further, when the average value of the minimum values and the average value of the maximum values are obtained from these values, the average value of the minimum values may be at least the lower limit value of the thickness of the protective film-forming film described above. The average value of the maximum values may be equal to or less than the upper limit value of the thickness of the protective film-forming film.

The protective film-forming film can be formed using a protective film-forming composition containing its constituent materials. For example, the protective film-forming film can be formed on the target site by applying the protective film-forming composition to the surface to be formed of the protective film-forming film and drying it as necessary. 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.

Coating of the protective composition may be performed by a known method, for example, air knife coater, blade coater, bar coater, gravure coater, roll coater, roll knife coater, curtain coater, die coater, knife coater, screen. A method using various coaters such as a coater, a Mayer bar coater, and a kiss coater can be mentioned.

Drying conditions for the composition for forming a protective film are not particularly limited, but when the composition for forming a protective film contains a solvent described later, it is preferable to heat and dry the composition. The protective film-forming composition containing a solvent is preferably dried, for example, at 70 to 130° C. for 10 seconds to 5 minutes. However, when the protective film-forming composition is thermosetting, it is preferable to dry the protective film-forming composition so that the formed protective film-forming film is not thermally cured.

The protective film-forming film and the protective film-forming composition will be described in detail below for each type.

○ Thermosetting Protective Film-Forming Film Preferable thermosetting protective film-forming film includes, for example, a film containing a polymer component (A) and a thermosetting component (B).
The polymer component (A) is a component that can be regarded as being formed by a polymerization reaction of a polymerizable compound.
The thermosetting component (B) is a component that can undergo a curing (polymerization) reaction with heat as a reaction trigger. In the present invention, the polymerization reaction also includes a polycondensation reaction.

The curing conditions when the thermosetting film for forming a thermosetting protective film is adhered to the back surface of the semiconductor wafer and then thermally cured are not particularly limited as long as the degree of curing is such that the cured product sufficiently exhibits its function. It may be appropriately selected according to the type of film for forming a curable protective film.
For example, the heating temperature during thermosetting of the film for forming a thermosetting protective film is preferably 100 to 200°C, more preferably 110 to 180°C, and particularly preferably 120 to 170°C. . The heating time for curing is preferably 0.5 to 5 hours, more preferably 0.5 to 3 hours, and particularly preferably 1 to 2 hours.

<Composition for forming a thermosetting protective film (III-1)>
Preferred thermosetting protective film-forming compositions include, for example, a thermosetting protective film-forming composition (III-1) containing a polymer component (A) and a thermosetting component (B) (this specification may be simply abbreviated as “composition (III-1)”) and the like.

[Polymer component (A)]
The polymer component (A) is a component for imparting film-forming properties, flexibility, and the like to the thermosetting protective film-forming film.
The polymer component (A) contained in the composition (III-1) and the film for forming a thermosetting protective film may be of one type or two or more types, and when there are two or more types, combinations thereof. and ratio can be selected arbitrarily.

Examples of the polymer component (A) include acrylic resins, polyesters, urethane resins, acrylic urethane resins, silicone resins, rubber resins, phenoxy resins, thermosetting polyimides, etc. Acrylic resins are preferred. .

Examples of the acrylic resin in the polymer component (A) include known acrylic polymers.
The weight average molecular weight (Mw) of the acrylic resin is preferably from 10,000 to 2,000,000, more preferably from 100,000 to 1,500,000. When the weight-average molecular weight of the acrylic resin is at least the lower limit, the shape stability (stability over time during storage) of the film for forming a thermosetting protective film is improved. Further, when the weight average molecular weight of the acrylic resin is equal to or less than the above upper limit, the film for forming a thermosetting protective film can easily follow the uneven surface of the adherend, and the adherend and the thermosetting protective film can be formed. The occurrence of voids and the like between the film and the film for use is further suppressed.

As used herein, the weight average molecular weight is a polystyrene-equivalent value measured by a gel permeation chromatography (GPC) method, unless otherwise specified.

The glass transition temperature (Tg) of the acrylic resin is preferably -60 to 70°C, more preferably -30 to 50°C. When the Tg of the acrylic resin is equal to or higher than the lower limit, for example, the adhesive force between the cured product of the protective film-forming film (that is, the protective film) and the support sheet is suppressed, and the peelability of the support sheet is moderate. improves. In addition, when the Tg of the acrylic resin is equal to or less than the upper limit, the adhesive strength of the thermosetting protective film-forming film and the protective film to the adherend is improved.
The Tg of the resins in this specification is not limited to acrylic resins, and is, for example, from −70° C. using a differential scanning calorimeter (DSC) at a heating rate or cooling rate of 10° C./min. It is obtained by changing the temperature of the object to be measured between 150° C. and confirming the inflection point.

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

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

The acrylic resin is, for example, one or more monomers selected from (meth)acrylic acid, itaconic acid, vinyl acetate, acrylonitrile, styrene, N-methylolacrylamide, etc., in addition to the (meth)acrylic acid ester. may be copolymerized.

Monomers constituting the acrylic resin may be of one type or two or more types, and in the case of two or more types, the combination and ratio thereof can be arbitrarily selected.

Acrylic resins may have functional groups capable of bonding with other compounds, such as vinyl groups, (meth)acryloyl groups, amino groups, hydroxyl groups, carboxy groups, and isocyanate groups. The functional group of the acrylic resin may be bonded to another compound via a cross-linking agent (F) described later, or may be directly bonded to another compound without the cross-linking agent (F). . By bonding the acrylic resin to other compounds via the functional group, there is a tendency for the reliability of the package obtained using the protective film-forming composite sheet to improve.

In the present invention, as the polymer component (A), a thermoplastic resin other than an acrylic resin (hereinafter sometimes simply referred to as "thermoplastic resin") is used alone without using an acrylic resin. Alternatively, it may be used in combination with an acrylic resin. By using the thermoplastic resin, the peelability of the protective film from the support sheet is improved, and the thermosetting protective film forming film easily follows the uneven surface of the adherend, and the adherend and thermosetting are improved. Occurrence of voids and the like between the film and the film for forming a protective film may be further suppressed.

The weight average molecular weight of the thermoplastic resin is preferably 1,000 to 100,000, more preferably 3,000 to 80,000.

The glass transition temperature (Tg) of the thermoplastic resin is preferably -30 to 150°C, more preferably -20 to 120°C.

Examples of the thermoplastic resin include polyester, polyurethane, phenoxy resin, polybutene, polybutadiene, polystyrene and the like.

The thermoplastic resin contained in the composition (III-1) and the film for forming a thermosetting protective film may be of only one type, or may be of two or more types. can be chosen arbitrarily.

In the composition (III-1), the ratio of the content of the polymer component (A) to the total content of all components other than the solvent (that is, the content of the polymer component (A) of the thermosetting protective film-forming film content) is preferably from 5 to 85% by mass, more preferably from 5 to 75% by mass, regardless of the type of polymer component (A), for example, from 5 to 65% by mass, from 5 to Any of 50% by mass and 10 to 35% by mass may be used.

The polymer component (A) may also correspond to the thermosetting component (B). In the present invention, when the composition (III-1) contains components corresponding to both the polymer component (A) and the thermosetting component (B), the composition (III-1) is , a polymeric component (A) and a thermosetting component (B).

[Thermosetting component (B)]
The thermosetting component (B) is a component for curing the thermosetting protective film-forming film.
The composition (III-1) and the thermosetting component (B) contained in the film for forming a thermosetting protective film may be of one type or two or more types. Any combination and ratio can be selected.

Examples of the thermosetting component (B) include epoxy thermosetting resins, thermosetting polyimides, polyurethanes, unsaturated polyesters, and silicone resins, with epoxy thermosetting resins being preferred.

(epoxy thermosetting resin)
The epoxy thermosetting resin consists of an epoxy resin (B1) and a thermosetting agent (B2).
The epoxy thermosetting resin contained in the composition (III-1) and the film for forming a thermosetting protective film may be only one type, or may be two or more types, and when there are two or more types, a combination thereof. and ratio can be selected arbitrarily.

・Epoxy resin (B1)
Examples of the epoxy resin (B1) include known ones, such as polyfunctional epoxy resins, biphenyl compounds, bisphenol A diglycidyl ether and hydrogenated products thereof, ortho-cresol novolak epoxy resins, dicyclopentadiene type epoxy resins, Biphenyl-type epoxy resins, bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, phenylene skeleton-type epoxy resins, and other epoxy compounds having a functionality of two or more can be used.

As the epoxy resin (B1), an epoxy resin having an unsaturated hydrocarbon group may be used. Epoxy resins having unsaturated hydrocarbon groups have higher compatibility with acrylic resins than epoxy resins having no unsaturated hydrocarbon groups. Therefore, by using an epoxy resin having an unsaturated hydrocarbon group, the reliability of a semiconductor chip with a protective film obtained using a composite sheet for forming a protective film is improved.

The epoxy resin having an unsaturated hydrocarbon group includes, for example, a compound obtained by converting a part of the epoxy groups of a polyfunctional epoxy resin into a group having an unsaturated hydrocarbon group. Such a compound can be obtained, for example, by addition reaction of (meth)acrylic acid or a derivative thereof to an epoxy group.
Examples of the epoxy resin having an unsaturated hydrocarbon group include compounds in which a group having an unsaturated hydrocarbon group is directly bonded to an aromatic ring or the like that constitutes the epoxy resin.
The unsaturated hydrocarbon group is a polymerizable unsaturated group, specific examples thereof include ethenyl group (vinyl group), 2-propenyl group (allyl group), (meth) acryloyl group, (meth) An acrylamide group and the like can be mentioned, and an acryloyl group is preferred.

Although the number average molecular weight of the epoxy resin (B1) is not particularly limited, it is preferably 300 to 30,000 from the viewpoint of the curability of the thermosetting protective film-forming film and the strength and heat resistance of the cured protective film. It is preferably from 300 to 10,000, and particularly preferably from 300 to 3,000.

As used herein, the number average molecular weight is a polystyrene-equivalent value measured by a gel permeation chromatography (GPC) method, unless otherwise specified.

The epoxy equivalent of the epoxy resin (B1) is preferably 100-1000 g/eq, more preferably 150-950 g/eq.

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

・Heat curing agent (B2)
The thermosetting agent (B2) functions as a curing agent for the epoxy resin (B1).
Examples of the thermosetting agent (B2) include compounds having two or more functional groups capable of reacting with epoxy groups in one molecule. Examples of the functional group include a phenolic hydroxyl group, an alcoholic hydroxyl group, an amino group, a carboxyl group, and an anhydrided group of an acid group. is preferably a group, more preferably a phenolic hydroxyl group or an amino group.

Among thermosetting agents (B2), phenol-based curing agents having phenolic hydroxyl groups include, for example, polyfunctional phenolic resins, biphenols, novolac-type phenolic resins, dicyclopentadiene-type phenolic resins, aralkyl-type phenolic resins, and the like. .
Among the thermosetting agents (B2), amine-based curing agents having an amino group include, for example, dicyandiamide.

The thermosetting agent (B2) may have an unsaturated hydrocarbon group.
Examples of the thermosetting agent (B2) having an unsaturated hydrocarbon group include, for example, a compound obtained by substituting a portion of the hydroxyl groups of a phenolic resin with a group having an unsaturated hydrocarbon group, an aromatic ring of the phenolic resin having an unsaturated Examples thereof include compounds in which a group having a saturated hydrocarbon group is directly bonded.
The unsaturated hydrocarbon group in the thermosetting agent (B2) is the same as the unsaturated hydrocarbon group in the above epoxy resin having an unsaturated hydrocarbon group.

When a phenol-based curing agent is used as the heat curing agent (B2), the heat curing agent (B2) preferably has a high softening point or a high glass transition temperature from the viewpoint of improving the peelability of the protective film from the support sheet. .

Of the thermosetting agent (B2), the number average molecular weight of resin components such as polyfunctional phenolic resins, novolac-type phenolic resins, dicyclopentadiene-type phenolic resins, and aralkyl-type phenolic resins is preferably 300 to 30,000. , 400 to 10,000, and particularly preferably 500 to 3,000.
Among 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.

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

In the composition (III-1) and the film for forming a thermosetting protective film, the content of the thermosetting agent (B2) is 0.1 to 500 parts by mass with respect to 100 parts by mass of the epoxy resin (B1). It is preferably 1 to 200 parts by mass, more preferably 1 to 200 parts by mass, for example, 1 to 100 parts by mass, 1 to 50 parts by mass, 1 to 25 parts by mass, and 1 to 10 parts by mass. There may be. When the content of the thermosetting agent (B2) is at least the lower limit, curing of the film for forming a thermosetting protective film proceeds more easily. In addition, since the content of the thermosetting agent (B2) is equal to or less than the upper limit, the moisture absorption rate of the thermosetting protective film-forming film is reduced, and the composite sheet for forming a protective film is obtained. Package reliability is improved.

In the composition (III-1) and the film for forming a thermosetting protective film, the content of the thermosetting component (B) (for example, the total content of the epoxy resin (B1) and the thermosetting agent (B2)) is It is preferably 20 to 500 parts by mass, more preferably 30 to 300 parts by mass, and even more preferably 40 to 150 parts by mass with respect to 100 parts by mass of the content of the polymer component (A). , for example, 45 to 100 parts by mass, and 50 to 80 parts by mass. When the content of the thermosetting component (B) is within such a range, for example, the adhesive force between the cured product of the protective film-forming film and the support sheet is suppressed, and the peelability of the support sheet is improved. do.

[Curing accelerator (C)]
The composition (III-1) and the film for forming a thermosetting protective film may contain a curing accelerator (C). The curing accelerator (C) is a component for adjusting the curing speed of composition (III-1).
Preferred curing accelerators (C) include, for example, tertiary amines such as triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, tris(dimethylaminomethyl)phenol; 2-methylimidazole, 2-phenylimidazole. , 2-phenyl-4-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole (one or more hydrogen atoms other than hydrogen atoms) imidazole substituted with a group); organic phosphines such as tributylphosphine, diphenylphosphine, triphenylphosphine (phosphines in which one or more hydrogen atoms are substituted with an organic group); tetraphenylphosphonium tetraphenylborate, triphenylphosphine Tetraphenylboron salts such as tetraphenylborate and the like are included.

The curing accelerator (C) contained in the composition (III-1) and the film for forming a thermosetting protective film may be only one type, or may be two or more types, and when there are two or more types, combinations thereof and ratio can be selected arbitrarily.

When the curing accelerator (C) is used, the content of the curing accelerator (C) in the composition (III-1) and the film for forming a thermosetting protective film is equal to the content of the thermosetting component (B) of 100 It is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 7 parts by mass. When the content of the curing accelerator (C) is at least the lower limit, the effect of using the curing accelerator (C) can be obtained more remarkably. In addition, since the content of the curing accelerator (C) is equal to or less than the upper limit, for example, the highly polar curing accelerator (C) is contained in the film for forming a thermosetting protective film under high temperature and high humidity conditions. The effect of suppressing migration to the adhesive interface side with the adherend and segregation in , is enhanced, and the reliability of the semiconductor chip with a protective film obtained using the composite sheet for forming a protective film is further improved.

[Filler (D)]
The composition (III-1) and the film for forming a thermosetting protective film may contain a filler (D). By containing the filler (D) in the film for forming a thermosetting protective film, it becomes easier to adjust the water absorption rate and the rate of change in adhesive strength within the intended ranges. In addition, since the thermosetting protective film-forming film and the protective film contain the filler (D), it becomes easier to adjust the thermal expansion coefficient. Alternatively, the reliability of a semiconductor chip with a protective film obtained using the composite sheet for forming a protective film is further improved by optimizing for the object on which the protective film is to be formed. Moreover, the film for thermosetting protective film formation can also reduce the moisture absorption rate of a protective film, or improve heat dissipation by containing a filler (D).

The filler (D) may be either an organic filler or an inorganic filler, but is preferably an inorganic filler.
Preferable inorganic fillers include, for example, powders of silica, alumina, talc, calcium carbonate, titanium white, iron oxide, silicon carbide, boron nitride; beads obtained by spheroidizing these inorganic fillers; and surface modification of these inorganic fillers. products; single crystal fibers of these inorganic fillers; glass fibers and the like.
Among these, the inorganic filler is preferably silica or alumina, more preferably silica.

The filler (D) contained in the composition (III-1) and the film for forming a thermosetting protective film may be only one kind, or may be two or more kinds. Any ratio can be selected.

When the filler (D) is used, the ratio of the content of the filler (D) to the total content of all components other than the solvent in the composition (III-1) (i.e., thermosetting protective film-forming film The content of the filler (D) in) is preferably 5 to 80% by mass, more preferably 10 to 70% by mass, for example, 20 to 65% by mass, 30 to 65% by mass, and Any of 40 to 65% by mass or the like may be used. When the content of the filler (D) is within such a range, it becomes easier to adjust the coefficient of thermal expansion, and the strength of the film for forming a protective film and the protective film are further improved.

[Coupling agent (E)]
The composition (III-1) and the film for forming a thermosetting protective film may contain a coupling agent (E). By using a coupling agent (E) having a functional group capable of reacting with an inorganic compound or an organic compound, the adhesiveness and adhesion of the thermosetting protective film-forming film to the adherend can be improved. can. Further, by using the coupling agent (E), the cured product (protective film) of the film for forming a thermosetting protective film is improved in water resistance without impairing heat resistance.

The coupling agent (E) is preferably a compound having a functional group capable of reacting with the functional group of the polymer component (A), thermosetting component (B), etc., and is preferably a silane coupling agent. more preferred.
Preferred silane coupling agents include, for example, 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropylmethyldiethoxysilane, 3-glycidyloxypropyltriethoxysilane, 3-glycidyloxymethyldiethoxysilane, 2- (3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-(2-aminoethylamino)propyltrimethoxysilane, 3-(2-amino ethylamino)propylmethyldiethoxysilane, 3-(phenylamino)propyltrimethoxysilane, 3-anilinopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropylmethyl dimethoxysilane, bis(3-triethoxysilylpropyl)tetrasulfane, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriacetoxysilane, imidazolesilane and the like.

The composition (III-1) and the coupling agent (E) contained in the film for forming a thermosetting protective film may be only one kind, or may be two or more kinds, and when there are two or more kinds, combinations thereof and ratio can be selected arbitrarily.

When the coupling agent (E) is used, the content of the coupling agent (E) in the composition (III-1) and the film for forming a thermosetting protective film is the polymer component (A) and the thermosetting component With respect to 100 parts by mass of the total content of (B), it is preferably 0.03 to 20 parts by mass, more preferably 0.05 to 10 parts by mass, and 0.1 to 5 parts by mass. is particularly preferred. When the content of the coupling agent (E) is at least the lower limit, the dispersibility of the filler (D) in the resin is improved and the adhesion of the thermosetting protective film forming film to the adherend is improved. The effects of using the coupling agent (E), such as improved properties, can be obtained more remarkably. Moreover, generation|occurrence|production of outgassing is suppressed more because the said content of a coupling agent (E) is below the said upper limit.

[Crosslinking agent (F)]
As the polymer component (A), those having a functional group such as a vinyl group, (meth)acryloyl group, amino group, hydroxyl group, carboxyl group, isocyanate group, etc., capable of bonding with other compounds, such as the acrylic resins described above. When used, the composition (III-1) and the thermosetting protective film-forming film may contain a cross-linking agent (F). The cross-linking agent (F) is a component for cross-linking by binding the functional groups in the polymer component (A) to other compounds. The initial adhesive strength and cohesive strength of the can be adjusted.

Examples of the cross-linking agent (F) include an organic polyvalent isocyanate compound, an organic polyvalent imine compound, a metal chelate cross-linking agent (a cross-linking agent having a metal chelate structure), an aziridine cross-linking agent (a cross-linking agent having an aziridinyl group), and the like. is mentioned.

Examples of the organic polyisocyanate compounds include aromatic polyisocyanate compounds, aliphatic polyisocyanate compounds and alicyclic polyisocyanate compounds (hereinafter collectively referred to as "aromatic polyisocyanate compounds, etc."). trimers, isocyanurates and adducts of the aromatic polyvalent isocyanate compounds; terminal isocyanate urethane prepolymers obtained by reacting the aromatic polyvalent isocyanate compounds and the like with polyol compounds. etc. The "adduct" is a mixture of the aromatic polyisocyanate compound, the aliphatic polyisocyanate compound or the alicyclic polyisocyanate compound and a low molecular weight compound such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane or castor oil. It means a reactant with a compound containing molecularly active hydrogen. Examples of the adduct include a xylylene diisocyanate adduct of trimethylolpropane as described later. Moreover, the term "terminal isocyanate urethane prepolymer" is as described above.

More specifically, the organic polyvalent isocyanate compound includes, for example, 2,4-tolylene diisocyanate; 2,6-tolylene diisocyanate; 1,3-xylylene diisocyanate; 1,4-xylylene diisocyanate; diphenylmethane-4 ,4'-diisocyanate; diphenylmethane-2,4'-diisocyanate; 3-methyldiphenylmethane diisocyanate; hexamethylene diisocyanate; isophorone diisocyanate; dicyclohexylmethane-4,4'-diisocyanate; Compounds in which one or more of tolylene diisocyanate, hexamethylene diisocyanate and xylylene diisocyanate are added to all or part of the hydroxyl groups of polyols such as propane; lysine diisocyanate and the like.

Examples of the organic polyvalent imine compound include N,N'-diphenylmethane-4,4'-bis(1-aziridinecarboxamide), trimethylolpropane-tri-β-aziridinylpropionate, and tetramethylolmethane. -tri-β-aziridinylpropionate, N,N'-toluene-2,4-bis(1-aziridinecarboxamide) triethylene melamine, and the like.

When an organic polyvalent isocyanate compound is used as the cross-linking agent (F), it is preferable to use a hydroxyl group-containing polymer as the polymer component (A). When the cross-linking agent (F) has an isocyanate group and the polymer component (A) has a hydroxyl group, the reaction between the cross-linking agent (F) and the polymer component (A) causes the formation of a thermosetting protective film-forming film. A crosslinked structure can be easily introduced.

The cross-linking agent (F) contained in the composition (III-1) and the film for forming a thermosetting protective film may be of only one type, or may be of two or more types. Any ratio can be selected.

When the cross-linking agent (F) is used, the content of the cross-linking agent (F) in the composition (III-1) is 0.01 to 20 parts by mass with respect to 100 parts by mass of the polymer component (A). , more preferably 0.1 to 10 parts by mass, and particularly preferably 0.5 to 5 parts by mass. When the content of the cross-linking agent (F) is at least the lower limit, the effect of using the cross-linking agent (F) can be obtained more remarkably. Moreover, excessive use of a crosslinking agent (F) is suppressed because the said content of a crosslinking agent (F) is below the said upper limit.

[Energy ray-curable resin (G)]
Composition (III-1) may contain an energy ray-curable resin (G). Since the thermosetting protective film-forming film contains the energy ray-curable resin (G), the properties thereof can be changed by irradiation with energy rays.

The energy ray-curable resin (G) is obtained by polymerizing (curing) an energy ray-curable compound.
Examples of the energy ray-curable compound include compounds having at least one polymerizable double bond in the molecule, and acrylate compounds having a (meth)acryloyl group are preferred.

Examples of the acrylate compounds include trimethylolpropane tri(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol monohydroxypenta ( Chain aliphatic skeleton-containing (meth)acrylates such as meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,4-butylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate; Cycloaliphatic skeleton-containing (meth)acrylates such as cyclopentanyl di(meth)acrylate; polyalkylene glycol (meth)acrylates such as polyethylene glycol di(meth)acrylate; oligoester (meth)acrylates; urethane (meth)acrylate oligomers epoxy-modified (meth)acrylates; polyether (meth)acrylates other than the above-mentioned polyalkylene glycol (meth)acrylates; and itaconic acid oligomers.

The energy ray-curable compound preferably has a weight average molecular weight of 100 to 30,000, more preferably 300 to 10,000.

The energy ray-curable compounds used for polymerization may be of one type or two or more types, and when two or more types are used, their combination and ratio can be arbitrarily selected.

The energy ray-curable resin (G) contained in the composition (III-1) may be of one type or two or more types, and when there are two or more types, the combination and ratio thereof can be arbitrarily selected. .

When using the energy ray-curable resin (G), the content of the energy ray-curable resin (G) in the composition (III-1) is preferably 1 to 95% by mass, more preferably 5 to 90% by mass. more preferably 10 to 85% by mass.

[Photoinitiator (H)]
When the composition (III-1) contains the energy ray-curable resin (G), it contains a photopolymerization initiator (H) in order to efficiently promote the polymerization reaction of the energy ray-curable resin (G). may be

Examples of the photopolymerization initiator (H) in the composition (III-1) include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin benzoic acid, benzoin methyl benzoate, and benzoin dimethyl ketal. benzoin compounds such as acetophenone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 2,2-dimethoxy-1,2-diphenylethan-1-one and other acetophenone compounds; Acylphosphine oxide compounds such as 4,6-trimethylbenzoyl)phenylphosphine oxide and 2,4,6-trimethylbenzoyldiphenylphosphine oxide; Sulfide compounds such as benzylphenyl sulfide and tetramethylthiuram monosulfide; 1-Hydroxycyclohexyl α-ketol compounds such as phenylketone; azo compounds such as azobisisobutyronitrile; titanocene compounds such as titanocene; thioxanthone compounds such as thioxanthone; peroxide compounds; diketone compounds such as diacetyl; 4-diethylthioxanthone; 1,2-diphenylmethane; 2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone; 2-chloroanthraquinone and the like.
Examples of the photopolymerization initiator include quinone compounds such as 1-chloroanthraquinone; and photosensitizers such as amines.

The photopolymerization initiator (H) contained in the composition (III-1) may be of one type or two or more types, and when there are two or more types, the combination and ratio thereof can be arbitrarily selected.

When the photopolymerization initiator (H) is used, the content of the photopolymerization initiator (H) in the composition (III-1) is It is preferably 0.1 to 20 parts by mass, more preferably 1 to 10 parts by mass, and particularly preferably 2 to 5 parts by mass.

[Colorant (I)]
The composition (III-1) and the film for forming a thermosetting protective film may contain a coloring agent (I).
Examples of the coloring agent (I) include known ones such as inorganic pigments, organic pigments, and organic dyes.

Examples of the organic pigments and organic dyes include aminium dyes, cyanine dyes, merocyanine dyes, croconium dyes, squalium dyes, azulenium dyes, polymethine dyes, naphthoquinone dyes, pyrylium dyes, and phthalocyanines. dyes, naphthalocyanine dyes, naphtholactam dyes, azo dyes, condensed azo dyes, indigo dyes, perinone dyes, perylene dyes, dioxazine dyes, quinacridone dyes, isoindolinone dyes, quinophthalone dyes , pyrrole dyes, thioindigo dyes, metal complex dyes (metal complex dyes), dithiol metal complex dyes, indolephenol dyes, triallylmethane dyes, anthraquinone dyes, dioxazine dyes, naphthol dyes, azomethine dyes dyes, benzimidazolone-based dyes, pyranthrone-based dyes, threne-based colors, and the like.

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

The composition (III-1) and the colorant (I) contained in the thermosetting protective film-forming film may be of one type or two or more types. Any ratio can be selected.

When the colorant (I) is used, the content of the colorant (I) in the thermosetting protective film-forming film may be appropriately adjusted according to the purpose. For example, by adjusting the content of the coloring agent (I) in the thermosetting protective film-forming film and adjusting the light transmittance of the protective film, the visibility of printing when laser printing is performed on the protective film can be adjusted. Also, by adjusting the content of the coloring agent (I) in the thermosetting protective film-forming film, it is possible to improve the design of the protective film and to make the grinding marks on the back surface of the semiconductor wafer less visible. Considering these points, in the composition (III-1), the ratio of the content of the coloring agent (I) to the total content of all components other than the solvent (i.e., the coloring of the thermosetting protective film-forming film The content of agent (I)) is preferably 0.1 to 10% by mass, more preferably 0.1 to 7.5% by mass, and 0.1 to 5% by mass. Especially preferred. When the content of the colorant (I) is at least the lower limit, the effect of using the colorant (I) is more remarkably obtained. In addition, when the content of the colorant (I) is equal to or less than the upper limit, an excessive decrease in the light transmittance of the film for forming a thermosetting protective film is suppressed.

[General purpose additive (J)]
The composition (III-1) and the film for forming a thermosetting protective film may contain a general-purpose additive (J) within a range that does not impair the effects of the present invention.
The general-purpose additive (J) may be a known one, can be arbitrarily selected according to the purpose, and is not particularly limited. Preferred examples include plasticizers, antistatic agents, antioxidants, gettering agents, and the like. is mentioned.

The general-purpose additive (J) contained in the composition (III-1) and thermosetting protective film-forming film may be only one kind, or may be two or more kinds, and when there are two or more kinds, a combination thereof and ratio can be selected arbitrarily.
The content of the general-purpose additive (J) in the composition (III-1) and thermosetting protective film-forming film is not particularly limited, and may be appropriately selected according to the purpose.

[solvent]
Composition (III-1) preferably further contains a solvent. The composition (III-1) containing a solvent is easy to handle.
Although the solvent is not particularly limited, preferred examples include hydrocarbons such as toluene and xylene; alcohols such as methanol, ethanol, 2-propanol, isobutyl alcohol (2-methylpropan-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;
Composition (III-1) may contain only one kind of solvent, or two or more kinds of solvents.

The solvent contained in the composition (III-1) is preferably methyl ethyl ketone or the like from the viewpoint that the components contained in the composition (III-1) can be more uniformly mixed.

<<Method for producing composition for forming thermosetting protective film>>
A composition for forming a thermosetting protective film such as composition (III-1) is obtained by blending each component for constituting the composition.
There are no particular restrictions on the order of addition of each component when blending, and two or more components may be added at the same time.
When a solvent is used, the solvent may be mixed with any compounding component other than the solvent and used by diluting this compounding component in advance, or any compounding component other than the solvent may be diluted in advance. You may use by mixing a solvent with these compounding ingredients, without preserving.
The method of mixing each component at the time of blending is not particularly limited, and may be selected from known methods such as a method of mixing by rotating a stirrer or a stirring blade; a method of mixing using a mixer; a method of mixing by applying ultrasonic waves. It can be selected as appropriate.
The temperature and time at which each component is added and mixed are not particularly limited as long as each compounded component does not deteriorate, and may be adjusted as appropriate, but the temperature is preferably 15 to 30°C.

○ Energy ray-curable protective film-forming film Examples of the energy ray-curable protective film-forming film include those containing the energy ray-curable component (a). Those containing are preferred.
In the energy ray-curable protective film-forming film, the energy ray-curable component (a) is preferably uncured, preferably adhesive, and more preferably uncured and adhesive. Here, "energy ray" and "energy ray curability" are as explained above.

The curing conditions for curing the energy ray-curable protective film-forming film after being attached to the back surface of the semiconductor wafer are not particularly limited as long as the degree of curing is such that the cured product sufficiently exhibits its function. It may be appropriately selected according to the type of film for forming a radiation-curable protective film.
For example, when the energy ray-curable protective film-forming film is cured, the illuminance of the energy ray is preferably 120 to 280 mW/cm ² . It is preferable that the light quantity of the energy beam during the curing is 100 to 1000 mJ/cm ² .

<Composition for forming energy ray-curable protective film (IV-1)>
Preferred energy ray-curable protective film-forming compositions include, for example, the energy ray-curable protective film-forming composition (IV-1) containing the energy ray-curable component (a) (in the present specification, may be simply abbreviated as “composition (IV-1)”) and the like.

[Energy ray-curable component (a)]
The energy ray-curable component (a) is a component that is cured by irradiation with energy rays, and imparts film-forming properties, flexibility, etc. to the film for forming an energy ray-curable protective film, and provides hard protection after curing. It is also a component for forming a film.
Examples of the energy ray-curable component (a) include a polymer (a1) having an energy ray-curable group and having a weight average molecular weight of 80,000 to 2,000,000, and a polymer (a1) having an energy ray-curable group and having a molecular weight of 100 to 80,000. A compound (a2) can be mentioned. At least a part of the polymer (a1) may be crosslinked with a crosslinking agent, or may not be crosslinked.

(Polymer (a1) having an energy ray-curable group and having a weight average molecular weight of 80,000 to 2,000,000)
Examples of the polymer (a1) having an energy ray-curable group and having a weight average molecular weight of 80,000 to 2,000,000 include an acrylic polymer (a11) having a functional group capable of reacting with a group possessed by another compound, and An acrylic resin (a1-1) obtained by reacting a functional group-reactive group and an energy ray-curable compound (a12) having an energy ray-curable group such as an energy ray-curable double bond. .

Examples of the functional group capable of reacting with a group possessed by another compound include a hydroxyl group, a carboxyl group, an amino group, and a substituted amino group (one or two hydrogen atoms of the amino group are substituted with a group other than a hydrogen atom). groups), epoxy groups, and the like. However, from the viewpoint of preventing corrosion of circuits such as semiconductor wafers and semiconductor chips, the functional group is preferably a group other than the carboxyl group.
Among these, the functional group is preferably a hydroxyl group.

- Acrylic polymer having a functional group (a11)
Examples of the acrylic polymer (a11) having the functional group include those obtained by copolymerizing an acrylic monomer having the functional group and an acrylic monomer having no functional group. In addition to the monomers, monomers other than acrylic monomers (non-acrylic monomers) may be copolymerized.
Further, the acrylic polymer (a11) may be a random copolymer or a block copolymer, and a known polymerization method may be employed.

Examples of acrylic monomers having functional groups include hydroxyl group-containing monomers, carboxy group-containing monomers, amino group-containing monomers, substituted amino group-containing monomers, and epoxy group-containing monomers.

Examples of the hydroxyl group-containing monomer include hydroxymethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, (meth) Hydroxyalkyl (meth)acrylates such as 2-hydroxybutyl acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; Saturated alcohol (unsaturated alcohol having no (meth)acryloyl skeleton) and the like can be mentioned.

Examples of the carboxy group-containing monomer include ethylenically unsaturated monocarboxylic acids (monocarboxylic acids having an ethylenically unsaturated bond) such as (meth)acrylic acid and crotonic acid; fumaric acid, itaconic acid, maleic acid, citracone; ethylenically unsaturated dicarboxylic acids (dicarboxylic acids having an ethylenically unsaturated bond) such as acids; anhydrides of the ethylenically unsaturated dicarboxylic acids; (meth)acrylic acid carboxyalkyl esters such as 2-carboxyethyl methacrylate; be done.

The acrylic monomer having the functional group is preferably a hydroxyl group-containing monomer.

The acrylic monomer having a functional group, which constitutes the acrylic polymer (a11), may be of only one type, or may be of two or more types. You can choose.

Examples of acrylic monomers having no functional group include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, and n (meth) acrylate. -butyl, 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, n-octyl (meth)acrylate, n-nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, (meth)acrylate Undecyl acrylate, dodecyl (meth) acrylate (lauryl (meth) acrylate), tridecyl (meth) acrylate, tetradecyl (meth) acrylate (myristyl (meth) acrylate), pentadecyl (meth) acrylate, (meth) ) hexadecyl acrylate (palmityl (meth) acrylate), heptadecyl (meth) acrylate, octadecyl (meth) acrylate (stearyl (meth) acrylate), etc., the alkyl group constituting the alkyl ester has 1 carbon number A (meth)acrylic acid alkyl ester having a chain structure of 1 to 18 and the like can be mentioned.

Examples of acrylic monomers having no functional group include alkoxy groups such as methoxymethyl (meth)acrylate, methoxyethyl (meth)acrylate, ethoxymethyl (meth)acrylate, and ethoxyethyl (meth)acrylate. Alkyl group-containing (meth)acrylic acid esters; (meth)acrylic acid esters having an aromatic group, including (meth)acrylic acid aryl esters such as phenyl (meth)acrylate; non-crosslinkable (meth)acrylamides and Derivatives thereof; (meth)acrylic acid esters having a non-crosslinkable tertiary amino group such as N,N-dimethylaminoethyl (meth)acrylate and N,N-dimethylaminopropyl (meth)acrylate; .

The acrylic monomer having no functional group, which constitutes the acrylic polymer (a11), may be only one kind, or may be two or more kinds, and when there are two or more kinds, the combination and ratio thereof are arbitrary. can be selected to

Examples of the non-acrylic monomers include olefins such as ethylene and norbornene; vinyl acetate; and styrene.
The non-acrylic monomers constituting the acrylic polymer (a11) may be of one type or two or more types, and when there are two or more types, the combination and ratio thereof can be arbitrarily selected.

In the acrylic polymer (a11), the ratio (content) of the amount of the structural units derived from the acrylic monomer having the functional group to the total amount of the structural units constituting the acrylic polymer (a11) is 0.1 to 50 mass. %, more preferably 1 to 40% by mass, particularly preferably 3 to 30% by mass. When the ratio is within such a range, in the acrylic resin (a1-1) obtained by copolymerization of the acrylic polymer (a11) and the energy ray-curable compound (a12), energy The content of the radiation-curable group makes it possible to easily adjust the degree of curing of the protective film within a preferred range.

The acrylic polymer (a11) constituting the acrylic resin (a1-1) may be of only one type, or may be of two or more types. You can choose.

In the composition (IV-1), the ratio of the content of the acrylic resin (a1-1) to the total content of components other than the solvent (that is, the acrylic resin (a1 The content of -1)) is preferably 1 to 70% by mass, more preferably 5 to 60% by mass, and particularly preferably 10 to 50% by mass.

- Energy ray-curable compound (a12)
In the energy ray-curable compound (a12), one or two selected from the group consisting of an isocyanate group, an epoxy group and a carboxy group as a group capable of reacting with a functional group possessed by the acrylic polymer (a11). Those having the above are preferable, and those having an isocyanate group as the group are more preferable. For example, when the energy ray-curable compound (a12) has an isocyanate group as the group, the isocyanate group readily reacts with the hydroxyl group of the acrylic polymer (a11) having the hydroxyl group as the functional group.

The energy ray-curable compound (a12) preferably has 1 to 5, more preferably 1 to 3, energy ray-curable groups in one molecule.

Examples of the energy ray-curable compound (a12) include 2-methacryloyloxyethyl isocyanate, meta-isopropenyl-α,α-dimethylbenzyl isocyanate, methacryloyl isocyanate, allyl isocyanate, 1,1-(bisacryloyloxymethyl) ethyl isocyanate;
An acryloyl monoisocyanate compound obtained by reacting a diisocyanate compound or polyisocyanate compound with hydroxyethyl (meth)acrylate;
An acryloyl monoisocyanate compound obtained by reacting a diisocyanate compound or polyisocyanate compound, a polyol compound, and hydroxyethyl (meth)acrylate, and the like.
Among these, the energy ray-curable compound (a12) is preferably 2-methacryloyloxyethyl isocyanate.

The energy ray-curable compound (a12) constituting the acrylic resin (a1-1) may be of only one type, or may be of two or more types. can be selected to

In the acrylic resin (a1-1), the content of energy ray-curable groups derived from the energy ray-curable compound (a12) with respect to the content of the functional groups derived from the acrylic polymer (a11). is preferably 20 to 120 mol %, more preferably 35 to 100 mol %, particularly preferably 50 to 100 mol %. When the proportion of the content is within such a range, the adhesive strength of the protective film after curing is increased. When the energy ray-curable compound (a12) is a monofunctional compound (having one group per molecule), the upper limit of the content ratio is 100 mol%. When the energy ray-curable compound (a12) is a polyfunctional compound (having two or more of the above groups in one molecule), the upper limit of the content ratio may exceed 100 mol %.

The weight average molecular weight (Mw) of the polymer (a1) is preferably from 100,000 to 2,000,000, more preferably from 300,000 to 1,500,000.

When the polymer (a1) is at least partially crosslinked by a crosslinking agent, the polymer (a1) is the acrylic polymer (a11) described above as constituting the acrylic polymer (a11). A monomer that does not fall under any of the monomers and has a group that reacts with a cross-linking agent may be polymerized and cross-linked at the group that reacts with the cross-linking agent, or the energy ray-curable compound ( A group derived from a12) that reacts with the functional group may be crosslinked.

The polymer (a1) contained in the composition (IV-1) and the energy ray-curable protective film-forming film may be one kind or two or more kinds. Any combination and ratio can be selected.

(Compound (a2) having an energy ray-curable group and having a molecular weight of 100 to 80,000)
Examples of the energy ray-curable group in the compound (a2) having an energy ray-curable group and having a molecular weight of 100 to 80000 include groups containing an energy ray-curable double bond, and preferred examples include (meth ) acryloyl group, vinyl group and the like.

The compound (a2) is not particularly limited as long as it satisfies the above conditions, but it is a low molecular weight compound having an energy ray-curable group, an epoxy resin having an energy ray-curable group, and an energy ray-curable group. A phenol resin etc. are mentioned.

Among the compounds (a2), low-molecular-weight compounds having an energy ray-curable group include, for example, polyfunctional monomers or oligomers, and acrylate compounds having a (meth)acryloyl group are preferred.
Examples of the acrylate compounds include 2-hydroxy-3-(meth)acryloyloxypropyl methacrylate, polyethylene glycol di(meth)acrylate, propoxylated ethoxylated bisphenol A di(meth)acrylate, 2,2-bis[4 -((meth)acryloxypolyethoxy)phenyl]propane, ethoxylated bisphenol A di(meth)acrylate, 2,2-bis[4-((meth)acryloxydiethoxy)phenyl]propane, 9,9-bis [4-(2-(meth)acryloyloxyethoxy)phenyl]fluorene, 2,2-bis[4-((meth)acryloxypolypropoxy)phenyl]propane, tricyclodecanedimethanol di(meth)acrylate, 1 , 10-decanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate ) acrylate, polypropylene glycol di(meth)acrylate, polytetramethylene glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, 2,2-bis [4-((meth)acryloxyethoxy)phenyl]propane, neopentyl glycol di(meth)acrylate, ethoxylated polypropylene glycol di(meth)acrylate, 2-hydroxy-1,3-di(meth)acryloxypropane, etc. a bifunctional (meth)acrylate of;
tris(2-(meth)acryloxyethyl)isocyanurate, ε-caprolactone-modified tris-(2-(meth)acryloxyethyl)isocyanurate, ethoxylated glycerin tri(meth)acrylate, pentaerythritol tri(meth)acrylate, Trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, ethoxylated pentaerythritol tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol poly(meth)acrylate, dipentaerythritol hexa( Polyfunctional (meth)acrylates such as meth)acrylates;
Examples include polyfunctional (meth)acrylate oligomers such as urethane (meth)acrylate oligomers.

Among the compounds (a2), the epoxy resin having an energy ray-curable group and the phenolic resin having an energy ray-curable group are described, for example, in paragraph 0043 of "JP-A-2013-194102". can use things. Such a resin also corresponds to a resin constituting a thermosetting component to be described later, but in the present invention it is treated as the compound (a2).

The weight average molecular weight of the compound (a2) is preferably 100-30,000, more preferably 300-10,000.

The compound (a2) contained in the composition (IV-1) and the energy ray-curable protective film-forming film may be of one type or two or more types, and when there are two or more types, a combination thereof. and ratio can be selected arbitrarily.

[Polymer (b) having no energy ray-curable group]
When the composition (IV-1) and the energy ray-curable protective film forming film contain the compound (a2) as the energy ray-curable component (a), the composition (IV-1) further contains a polymer having no energy ray-curable group. (b) is also preferably contained.
At least a part of the polymer (b) may be crosslinked with a crosslinking agent, or may not be crosslinked.

Examples of the polymer (b) having no energy ray-curable group include acrylic polymers, phenoxy resins, urethane resins, polyesters, rubber resins, and acrylic urethane resins.
Among these, the polymer (b) is preferably an acrylic polymer (hereinafter sometimes abbreviated as "acrylic polymer (b-1)").

The acrylic polymer (b-1) may be a known one, and may be, for example, a homopolymer of one acrylic monomer or a copolymer of two or more acrylic monomers. Alternatively, it may be a copolymer of one or more acrylic monomers and one or more monomers other than acrylic monomers (non-acrylic monomers).

Examples of the acrylic monomer constituting the acrylic polymer (b-1) include (meth)acrylic acid alkyl esters, (meth)acrylic acid esters having a cyclic skeleton, glycidyl group-containing (meth)acrylic acid esters, Examples include hydroxyl group-containing (meth)acrylic acid esters and substituted amino group-containing (meth)acrylic acid esters. Here, the "substituted amino group" is as described above.

Examples of the (meth)acrylic acid alkyl esters include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, and n-(meth)acrylate. Butyl, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, (meth)acrylate ) 2-ethylhexyl acrylate, isooctyl (meth)acrylate, n-octyl (meth)acrylate, n-nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, (meth)acrylic undecyl acid, dodecyl (meth)acrylate (lauryl (meth)acrylate), tridecyl (meth)acrylate, tetradecyl (meth)acrylate (myristyl (meth)acrylate), pentadecyl (meth)acrylate, (meth)acrylate The alkyl group constituting the alkyl ester, such as hexadecyl acrylate (palmityl (meth) acrylate), heptadecyl (meth) acrylate, octadecyl (meth) acrylate (stearyl (meth) acrylate), has 1 to 1 carbon atoms. A (meth)acrylic acid alkyl ester having a chain structure of 18 and the like can be mentioned.

Examples of (meth)acrylic acid esters having a cyclic skeleton include (meth)acrylic acid cycloalkyl esters such as isobornyl (meth)acrylate and dicyclopentanyl (meth)acrylate;
(meth)acrylic acid aralkyl ester such as benzyl (meth)acrylate;
(meth)acrylic acid cycloalkenyl esters such as (meth)acrylic acid dicyclopentenyl ester;
(Meth)acrylic acid cycloalkenyloxyalkyl esters such as (meth)acrylic acid dicyclopentenyloxyethyl ester and the like.

Examples of the glycidyl group-containing (meth)acrylic acid ester include glycidyl (meth)acrylate.
Examples of the hydroxyl group-containing (meth)acrylic acid ester include hydroxymethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 3-hydroxy (meth)acrylate. propyl, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate and the like.
Examples of the substituted amino group-containing (meth)acrylic acid ester include N-methylaminoethyl (meth)acrylate.

Examples of the non-acrylic monomers constituting the acrylic polymer (b-1) include olefins such as ethylene and norbornene; vinyl acetate; and styrene.

As the polymer (b) having no energy ray-curable group, at least a part of which is crosslinked by a crosslinking agent, for example, a reactive functional group in the polymer (b) reacted with a crosslinking agent. mentioned.
The reactive functional group may be appropriately selected according to the type of cross-linking agent, and is not particularly limited. For example, when the cross-linking agent is a polyisocyanate compound, the reactive functional group includes a hydroxyl group, a carboxyl group, an amino group, etc. Among these, a hydroxyl group having high reactivity with the isocyanate group is preferable. When the cross-linking agent is an epoxy-based compound, examples of the reactive functional group include a carboxy group, an amino group, an amide group, etc. Among these, a carboxy group having high reactivity with the epoxy group is preferable. . However, the reactive functional group is preferably a group other than the carboxy group from the viewpoint of preventing corrosion of the circuits of the semiconductor wafer or semiconductor chip.

Examples of the polymer (b) having a reactive functional group and not having an energy ray-curable group include those obtained by polymerizing a monomer having at least the reactive functional group. In the case of the acrylic polymer (b-1), one or both of the acrylic monomer and the non-acrylic monomer exemplified as monomers constituting the acrylic polymer (b-1) are those having the reactive functional group. You can use it. Examples of the polymer (b) having a hydroxyl group as a reactive functional group include those obtained by polymerizing a hydroxyl group-containing (meth)acrylic acid ester. Examples thereof include those obtained by polymerizing a monomer in which one or more hydrogen atoms are substituted with the reactive functional groups in the acrylic monomers or non-acrylic monomers.

In the polymer (b) having a reactive functional group, the ratio (content) of the amount of structural units derived from a monomer having a reactive functional group to the total amount of structural units constituting the polymer (b) is 1 to 20. % by mass is preferable, and 2 to 10% by mass is more preferable. When the ratio is within such a range, the degree of cross-linking in the polymer (b) is in a more preferable range.

The weight-average molecular weight (Mw) of the polymer (b) having no energy ray-curable group is preferably 10,000 to 2,000,000 from the viewpoint of better film-forming properties of the composition (IV-1). It is more preferably 100,000 to 1,500,000. Here, the "weight average molecular weight" is as described above.

The polymer (b) having no energy ray-curable group contained in the composition (IV-1) and the film for forming an energy ray-curable protective film may be of one type or two or more types. When there are more than one species, their combination and ratio can be arbitrarily selected.

Examples of the composition (IV-1) include those containing either one or both of the polymer (a1) and the compound (a2). When the composition (IV-1) contains the compound (a2), it preferably further contains a polymer (b) having no energy ray-curable group. It is also preferred to contain Further, the composition (IV-1) may contain both the polymer (a1) and the polymer (b) having no energy ray-curable group without containing the compound (a2). .

When the composition (IV-1) contains the polymer (a1), the compound (a2), and the polymer (b) having no energy ray-curable group, in the composition (IV-1), the The content of the compound (a2) is preferably 10 to 400 parts by mass with respect to 100 parts by mass of the total content of the polymer (a1) and the polymer (b) having no energy ray-curable group. , and more preferably 30 to 350 parts by mass.

In the composition (IV-1), the ratio of the total content of the energy ray-curable component (a) and the polymer (b) having no energy ray-curable group to the total content of components other than the solvent (i.e. , The total content of the energy ray-curable component (a) and the polymer (b) having no energy ray-curable group in the energy ray-curable protective film-forming film) is 5 to 90% by mass. It is preferably 10 to 80% by mass, and particularly preferably 20 to 70% by mass. When the content of the energy ray-curable component is in such a range, the energy ray-curable film for forming an energy ray-curable protective film has better energy ray curability.

The composition (IV-1), in addition to the energy ray-curable component, contains a thermosetting component, a filler, a coupling agent, a cross-linking agent, a photopolymerization initiator, a coloring agent, and general-purpose additives depending on the purpose. It may contain one or more selected from the group consisting of:

For example, by using the composition (IV-1) containing the energy ray-curable component and the thermosetting component, the energy ray-curable protective film-forming film formed has an adhesive strength to the adherend by heating. is improved, and the strength of the protective film formed from this energy ray-curable protective film-forming film is also improved.
In addition, the energy ray-curable protective film-forming film formed by using the composition (IV-1) containing the energy ray-curable component and the colorant is the thermosetting protective film-forming film described above. The same effects as when the film for use contains the coloring agent (I) are exhibited.

The thermosetting components, fillers, coupling agents, cross-linking agents, photopolymerization initiators, colorants, and general-purpose additives in the composition (IV-1) are, respectively, thermosetting components in the composition (III-1). The same as the chemical component (B), filler (D), coupling agent (E), cross-linking agent (F), photopolymerization initiator (H), colorant (I) and general-purpose additive (J). be done.

In the composition (IV-1), each of the thermosetting component, filler, coupling agent, cross-linking agent, photopolymerization initiator, colorant and general-purpose additive may be used alone or , may be used in combination of two or more types, and when two or more types are used in combination, their combination and ratio can be arbitrarily selected.

The content of the thermosetting component, filler, coupling agent, cross-linking agent, photopolymerization initiator, colorant and general-purpose additive in the composition (IV-1) may be appropriately adjusted according to the purpose. It is not particularly limited.

The composition (IV-1) preferably further contains a solvent because its handling properties are improved by dilution.
The solvent contained in composition (IV-1) includes, for example, the same solvent as in composition (III-1) described above.
Composition (IV-1) may contain only one solvent, or two or more solvents.

<<Method for producing composition for forming energy ray-curable protective film>>
An energy ray-curable protective film-forming composition such as composition (IV-1) is obtained by blending each component for constituting the composition.
There are no particular restrictions on the order of addition of each component when blending, and two or more components may be added at the same time.
When a solvent is used, the solvent may be mixed with any compounding component other than the solvent and used by diluting this compounding component in advance, or any compounding component other than the solvent may be diluted in advance. You may use by mixing a solvent with these compounding ingredients, without preserving.
The method of mixing each component at the time of blending is not particularly limited, and may be selected from known methods such as a method of mixing by rotating a stirrer or a stirring blade; a method of mixing using a mixer; a method of mixing by applying ultrasonic waves. It can be selected as appropriate.
The temperature and time at which each component is added and mixed are not particularly limited as long as each compounded component does not deteriorate, and may be adjusted as appropriate, but the temperature is preferably 15 to 30°C.

○ Film for forming a non-curable protective film The film for forming a non-curable protective film does not exhibit changes in properties due to curing, but in the present invention, it is attached to the target location such as the back surface of the semiconductor wafer. At this stage, it is considered that a protective film has been formed.

Preferred non-curable protective film-forming films include, for example, those containing a thermoplastic resin.

<Composition for forming a non-curable protective film (V-1)>
Examples of the non-curable protective film-forming composition include, for example, the non-curable protective film-forming composition (V-1) containing the thermoplastic resin (in the present specification, simply referred to as "composition (V-1 )” may be abbreviated).

[Thermoplastic resin]
The thermoplastic resin is not particularly limited.
As the thermoplastic resin, more specifically, for example, curable acrylic resins, polyesters, polyurethanes, phenoxy resins, polybutene, polybutadiene, polystyrene, etc. listed as the components of the composition (III-1) described above. and the same resins as those that are not.

The thermoplastic resin contained in the composition (V-1) and the non-curable protective film-forming film may be one kind or two or more kinds. can be chosen arbitrarily.

In the composition (V-1), the ratio of the content of the thermoplastic resin to the total content of components other than the solvent (that is, the content of the thermoplastic resin in the non-curable protective film-forming film) is It is preferably 5 to 90% by mass, and may be, for example, 10 to 80% by mass or 20 to 70% by mass.

The composition (V-1) contains, in addition to the thermoplastic resin, one or more selected from the group consisting of fillers, coupling agents, cross-linking agents, colorants and general-purpose additives, depending on the purpose. may contain.

For example, the non-curable protective film-forming film formed by using the composition (V-1) containing the thermoplastic resin and the colorant is the thermosetting protective film-forming film described above. The same effects as when the coloring agent (I) is contained are exhibited.

The filler, coupling agent, cross-linking agent, colorant and general-purpose additive in composition (V-1) are respectively the filler (D) and coupling agent (E) in composition (III-1). , cross-linking agent (F), colorant (I) and general-purpose additive (J).

In the composition (V-1), each of the filler, coupling agent, cross-linking agent, colorant and general-purpose additive may be used alone or in combination of two or more. , when two or more of them are used in combination, their combination and ratio can be arbitrarily selected.

The contents of the filler, coupling agent, cross-linking agent, colorant and general-purpose additive in the composition (V-1) may be appropriately adjusted according to the purpose, and are not particularly limited.

The composition (V-1) preferably further contains a solvent, since its handleability is improved by dilution.
The solvent contained in composition (V-1) includes, for example, the same solvent as in composition (III-1) described above.
Composition (V-1) may contain only one solvent, or two or more solvents.

<<Method for producing a composition for forming a non-curable protective film>>
A non-curable protective film-forming composition such as composition (V-1) is obtained by blending each component for constituting the composition.
There are no particular restrictions on the order of addition of each component when blending, and two or more components may be added at the same time.
When a solvent is used, the solvent may be mixed with any compounding component other than the solvent and used by diluting this compounding component in advance, or any compounding component other than the solvent may be diluted in advance. You may use by mixing a solvent with these compounding ingredients, without preserving.
The method of mixing each component at the time of blending is not particularly limited, and may be selected from known methods such as a method of mixing by rotating a stirrer or a stirring blade; a method of mixing using a mixer; a method of mixing by applying ultrasonic waves. It can be selected as appropriate.
The temperature and time at which each component is added and mixed are not particularly limited as long as each compounded component does not deteriorate, and may be adjusted as appropriate, but the temperature is preferably 15 to 30°C.

⊚Other Layers The support sheet may include other layers such as the intermediate layer in addition to the substrate and the pressure-sensitive adhesive layer within a range that does not impair the effects of the present invention.
In addition, the protective film-forming composite sheet may include other layers in addition to the base material, the pressure-sensitive adhesive layer, and the protective film-forming film within a range that does not impair the effects of the present invention. The other layer may be the other layer included in the support sheet, or may be arranged without direct contact with the support sheet.
The other layer can be arbitrarily selected according to the purpose, and its type is not particularly limited.

In one embodiment of the support sheet and protective film-forming composite sheet, for example, the adhesive layer is non-energy ray-curable and the adhesive layer has at least a structural unit derived from a (meth)acrylic acid alkyl ester. and a cross-linking agent. The maximum height roughness (Rz) of the first surface of the material is 0.01 to 8 μm.

In one embodiment of the support sheet and protective film-forming composite sheet, for example, the adhesive layer is non-energy ray-curable and the adhesive layer has at least a structural unit derived from a (meth)acrylic acid alkyl ester. and a cross-linking agent, and in the pressure-sensitive adhesive layer, the content of the cross-linking agent is 0.3 to 50 parts by mass with respect to 100 parts by mass of the acrylic polymer, and the acrylic The polymer has a structural unit derived from a (meth)acrylic acid alkyl ester in which the alkyl group has 4 or more carbon atoms and a structural unit derived from a hydroxyl group-containing monomer, and The maximum height roughness (Rz) is 0.01 to 8 μm.

In one embodiment of the support sheet and protective film-forming composite sheet, for example, the adhesive layer is non-energy ray-curable and the adhesive layer has at least a structural unit derived from a (meth)acrylic acid alkyl ester. and a cross-linking agent, and in the pressure-sensitive adhesive layer, the content of the cross-linking agent is 0.3 to 50 parts by mass with respect to 100 parts by mass of the acrylic polymer, and the acrylic The polymer has a structural unit derived from a (meth)acrylic acid alkyl ester in which the alkyl group has 4 or more carbon atoms and a structural unit derived from a hydroxyl group-containing monomer, and in the acrylic polymer, the hydroxyl group-containing monomer The content of the derived structural units is 1 to 35% by mass with respect to the total amount of the structural units, and the maximum height roughness (Rz) of the first surface of the substrate is 0.01 to 8 μm. Some things are mentioned.

In one embodiment of the support sheet and protective film-forming composite sheet, for example, the adhesive layer is non-energy ray-curable and the adhesive layer has at least a structural unit derived from a (meth)acrylic acid alkyl ester. and a cross-linking agent, and in the pressure-sensitive adhesive layer, the content of the cross-linking agent is 0.3 to 50 parts by mass with respect to 100 parts by mass of the acrylic polymer, and the acrylic The polymer has a structural unit derived from a (meth)acrylic acid alkyl ester in which the alkyl group has 4 or more carbon atoms and a structural unit derived from a hydroxyl group-containing monomer, and in the acrylic polymer, the hydroxyl group-containing monomer The content of the derived structural unit is 1 to 35% by mass with respect to the total amount of the structural units, the cross-linking agent is an isocyanate-based cross-linking agent, and the maximum height roughness of the first surface of the base material The thickness (Rz) is 0.01 to 8 μm.

◇Method for producing a protective film-forming composite sheet The protective film-forming composite sheet is, for example, a laminate composed of a substrate, an adhesive layer, and a protective film-forming film laminated in this order in the thickness direction. A step of producing a sheet (in this specification, may be referred to as a "laminated sheet producing step (1)"); and a step of storing the laminated sheet while pressing it in its thickness direction (in this specification, , sometimes referred to as a “laminated sheet storage step”), and (in this specification, sometimes referred to as a “manufacturing method (S1)”).
The method for forming each layer (base material, pressure-sensitive adhesive layer, and protective film-forming film) is as described above.
Each step of the manufacturing method (S1) will be described in more detail below.

◎Manufacturing method (S1)
<<Laminated sheet production process (1)>>
In the laminated sheet producing step (1), a laminated sheet is produced by laminating a substrate, an adhesive layer and a film for forming a protective film in this order in the thickness direction thereof.
In this step, for example, by laminating each of the above-described layers (base material, adhesive layer, protective film forming film, etc.) in a corresponding positional relationship, the same as the target protective film forming composite sheet A laminated sheet having a laminated structure is produced.
In this specification, unless otherwise specified, the term "laminate sheet" has the same laminate structure as the target protective film-forming composite sheet as described above, and the laminate sheet storage step is performed. Means what has not been done.

For example, when a pressure-sensitive adhesive layer is laminated on a substrate when producing a support sheet, the above-described pressure-sensitive adhesive composition may be applied onto the substrate and dried as necessary.

On the other hand, for example, when a protective film-forming film is laminated on the adhesive layer already laminated on the substrate, the protective film-forming composition is applied onto the adhesive layer to form a protective film. It is possible to form the forming film directly. Layers other than the protective film-forming film can also be laminated on the pressure-sensitive adhesive layer in the same manner using the composition for forming this layer. Thus, when forming a continuous two-layer laminated structure using either composition, the composition is further applied on the layer formed from the composition to form a new layer. It is possible to form However, of these two layers, the layer to be laminated later is formed in advance using the composition on another release film, and the side of the formed layer that is in contact with the release film is Preferably, the opposite exposed surface is laminated to the exposed surface of the remaining layer that has already been formed to form a continuous two-layer laminate structure. At this time, the composition is preferably applied to the release-treated surface of the release film. The release film may be removed as necessary after the laminated structure is formed.

For example, a composite sheet for forming a protective film in which a pressure-sensitive adhesive layer is laminated on a base material and a film for forming a protective film is laminated on the pressure-sensitive adhesive layer (the support sheet is a laminate of the base material and the pressure-sensitive adhesive layer). In the case of manufacturing a composite sheet for forming a protective film), the adhesive composition is applied on the substrate, and dried as necessary to laminate the adhesive layer on the substrate, and a separate A protective film-forming film is formed on the release film by applying a protective film-forming composition onto the release film and drying it as necessary. Then, the exposed surface of the film for forming a protective film is laminated to the exposed surface of the adhesive layer already laminated on the substrate, and the film for forming a protective film is laminated on the adhesive layer to obtain the laminated sheet. is obtained.

In the case of laminating the adhesive layer on the substrate, as described above, instead of coating the adhesive composition on the substrate, the adhesive composition is coated on the release film. , By drying as necessary, an adhesive layer is formed on the release film, and the exposed surface of this layer is attached to one surface of the base material to attach the adhesive layer to the base material. May be laminated.
In either method, the peeling film may be removed at any timing after forming the intended laminated structure.

In this way, all layers other than the base material constituting the protective film-forming composite sheet can be formed in advance on a release film and laminated by a method of bonding them to the surface of the desired layer. The laminated sheet may be produced by appropriately selecting the layer that employs such a step as leverage.

For example, the composite sheet for forming a protective film is usually stored with a release film attached to the surface of the outermost layer (for example, film for forming a protective film) opposite to the support sheet. Therefore, on this release film (preferably its release-treated surface), a composition for forming a layer constituting the outermost layer, such as a composition for forming a protective film, is applied and dried as necessary. Then, a layer constituting the outermost layer is formed on the release film, and the remaining layers are laminated on the exposed surface of this layer opposite to the side in contact with the release film by any of the above methods. Alternatively, the laminated sheet can be obtained by leaving the laminated sheet without removing the release film.

When the protective film-forming composite sheet includes the other layer, the step of providing the other layer at a suitable timing in the above-described laminated sheet preparation step (1) so as to be in a suitable arrangement position. It may be added as appropriate.

The shape of the laminated sheet produced in the laminated sheet producing step (1) is not particularly limited. For example, a long laminated sheet suitable for winding up as a roll may be produced, but a non-long laminated sheet of other shape may also be produced.

<<Laminated sheet storage process>>
In the laminated sheet storage step, the laminated sheet is stored while being pressed in its thickness direction.
In this step, as a method of storing the laminated sheet while pressurizing it, for example, the long laminated sheet is wound into a roll, and the wound laminated sheet is left as it is, and the pressure generated by the winding is A method of storing while adding to one or both sides of the laminated sheet; One side or both sides of the laminated sheet in an unfolded state without winding the long laminated sheet into a roll, or the laminated sheet that is not long In addition, there is a method of storing while applying pressure.

When the long laminated sheet is wound into a roll, the laminated sheet is preferably wound in its longitudinal direction.
When winding the laminated sheet, for example, the winding tension is preferably 150 to 170 N / m, the winding speed is preferably 45 to 55 m / min, and the taper rate (reduction rate) of the winding tension is It is preferably 85-95%. By adopting such winding conditions, the laminated sheet can be stored under a more suitable pressure. Such winding conditions are particularly suitable for application to laminated sheets having a thickness of 100 to 300 μm, a width of 300 to 500 mm, and a length of 40 to 60 m, for example. The width is not limited to this.

The laminated sheet may be wound, for example, at normal temperature or room temperature, or may be wound under the same temperature conditions as when the wound laminated sheet is stored under heat and pressure, as described later.

The laminated sheet wound into a roll may be stored at room temperature or room temperature, but is preferably stored while being heated. By storing under heat and pressure in this way, the lamination property of the adhesive layer and the film for forming a protective film, and the visibility of printing through the support sheet of the protective film or the film for forming a protective film, and the more excellent protection. A composite sheet for film formation is obtained.

When the laminated sheet is wound into a roll, the heating temperature during storage is not particularly limited, but is preferably 53 to 75°C, more preferably 55 to 70°C, and 57 to 65°C. It is particularly preferred to have

The storage time when the laminated sheet is wound into a roll is not particularly limited, but is preferably 24 to 720 hours (1 to 30 days), and 48 to 480 hours (2 to 20 days). More preferably, 72 to 240 hours (3 to 10 days) is particularly preferred.

Laminated sheets to be wound into a roll are, for example, a film for forming a protective film and a support sheet processed into a specific shape, and a laminate of a plurality of such processed support sheets and films for forming a protective film. On the side of the protective film-forming film in (1), the film may be laminated to a long release film and aligned in the longitudinal direction of the release film. In this case, the protective film-forming film preferably has the same or substantially the same plane shape (usually circular shape) as the semiconductor wafer. Moreover, the support sheet in this case preferably has the same or substantially the same outer peripheral shape as the jig for fixing the support sheet in the dicing machine. Further, in this case, it is preferable that a belt-like sheet is provided in the vicinity of the peripheral edge portion in the lateral direction of the bonding surface of the laminate so as not to overlap the laminate. This sheet is for suppressing the generation of steps (in this specification, sometimes referred to as "laminating marks") on the surface of the laminate when the laminate sheet is wound into a roll. . The lamination marks are caused by the lamination position of the laminate (laminate of the processed support sheet and protective film forming film) not matching in the radial direction of the roll in the roll of the laminate sheet. caused by high pressure on If the sheet is provided in the vicinity of the peripheral portion, such a high pressure is not applied to the surface of the laminate, and the generation of the lamination marks is suppressed.

When a long laminated sheet is unrolled without being wound into a roll, and when the laminated sheet is not long, a plurality of these laminated sheets can be further laminated and stored. preferable. When the laminated sheets are laminated in this way, it is preferable to match the directions and positions of the peripheral portions of the plurality of laminated sheets with each other.

The shape and size of the non-long laminated sheet (in other words, single laminated sheet) are not particularly limited. For example, the shape and size of the semiconductor wafer and the shape and size of the jig for fixing the support sheet in the dicing device, so as to be suitable for processing one semiconductor wafer using a dicing device. In addition, it is preferable that the shape and size of the laminated sheet are adjusted.

The laminated sheet in a laminated state may be stored at room temperature or room temperature, but is preferably stored while being heated. By storing under heat and pressure in this way, the lamination property of the adhesive layer and the film for forming a protective film, and the visibility of printing through the support sheet of the protective film or the film for forming a protective film, and the more excellent protection. A composite sheet for film formation is obtained.
Further, the heating temperature and the storage time when the laminated sheet in the laminated state is stored under pressure can be the same as those in the case of winding the above-described laminated sheet into a roll.

In the production method (S1), after the laminated sheet storage step is completed, the desired composite sheet for forming a protective film is obtained by releasing the pressure applied to the laminated sheet and, if necessary, the heating.

In the laminated sheet preparation step (1) of the production method (S1), the order of lamination (bonding) of the base material, the adhesive layer and the protective film forming film is not particularly limited, but a support sheet is prepared in advance ( In the case of laminating an adhesive layer in advance on the base material), preparing a protective film-forming film in advance, and laminating the protective film-forming film on the support sheet, the support sheet and the protective film-forming film are laminated. Either or both alone may be pressure stored in the same manner as for the laminated sheets described above before they are laminated. By pressurizing and storing the support sheet alone before lamination, the occurrence of the non-bonded region between the substrate and the pressure-sensitive adhesive layer can be more effectively suppressed. In addition, by pressurizing and storing the protective film-forming film alone before lamination, the surface (second surface) of the protective film-forming film and the protective film on the pressure-sensitive adhesive layer side has a small unevenness (smoothness is larger), and the designability of the protective film-forming film and the protective film is improved.

That is, the composite sheet for forming a protective film is obtained, for example, by laminating a film for forming a protective film on the adhesive layer of a support sheet in which a base material and an adhesive layer are laminated, thereby forming a base material and an adhesive layer. and a protective film-forming film laminated in this order in the thickness direction to produce a laminated sheet (in the present specification, this step may be referred to as a "laminated sheet producing step (2)"). and a step of storing the laminated sheet while applying pressure in its thickness direction (storage step), wherein, before the laminated sheet preparation step (2), any of the support sheet and the protective film forming film The step of storing one or both while pressing in the thickness direction (in this specification, the step of storing the support sheet is referred to as the "support sheet storage step", and the step of storing the protective film-forming film is referred to as It can also be produced by a production method (in this specification, sometimes referred to as "production method (S2)") further comprising a "protective film-forming film storage step").

◎Manufacturing method (S2)
In the production method (S2), the laminated sheet producing step (2) is performed as the laminated sheet producing step (1) described above, and either one or both of the supporting sheet storing step and the protective film forming film storing step are performed. It is the same as the manufacturing method (S1) described above except that it is additionally performed.

<<Laminated sheet production step (2)>>
In the laminated sheet preparation step (2), as described above, the support sheet is prepared in advance, the protective film-forming film is prepared in advance, and the protective film-forming film is laminated on the support sheet. is the same as the laminated sheet preparation step (1) in the production method (S1), except that the order of lamination is limited.

<<Supporting sheet storage step, protective film forming film storage step>>
In the support sheet storage step and the protective film forming film storage step, the laminate sheet storage step in the manufacturing method (S1) is performed except that the object to be stored is not the laminate sheet but the support sheet or the protective film formation film. can be done in the same way as
In this case, for example, the storage time of the support sheet and protective film-forming film is 24 to 720 hours (1 to 30 days), 48 to 480 hours (2 to 20 days), and 72 hours, as in the case of the laminated sheet. It can be anywhere from ˜240 hours (3-10 days).

On the other hand, in the support sheet storage step and the protective film forming film storage step, in addition to changing the storage object as described above, the storage object (support sheet or protective film forming film) is stored. Other than these changes, the time may be changed in the same manner as in the laminated sheet storage step in the manufacturing method (S1).
In this case, for example, the storage time of the support sheet and protective film-forming film is 12 to 720 hours (0.5 to 30 days), 12 to 480 hours (0.5 to 20 days), and 12 to 240 hours ( 0.5 to 10 days). However, this is an example of the storage time.

The present invention will be described in more detail below with reference to specific examples. However, the present invention is by no means limited to the examples shown below.

<Raw materials for manufacturing protective film-forming composition>
Raw materials used for producing the composition for forming a protective film are shown below.
- Polymer component (A)
(A)-1: Acrylic polymer (weight average molecular weight 370,000, glass transition temperature 6°C) obtained by copolymerizing methyl acrylate (85 parts by mass) and 2-hydroxyethyl acrylate (15 parts by mass)
・Thermosetting component (B1)
(B1)-1: Bisphenol A type epoxy resin (“jER828” manufactured by Mitsubishi Chemical Corporation, epoxy equivalent 184 to 194 g/eq)
(B1)-2: Bisphenol A type epoxy resin (“jER1055” manufactured by Mitsubishi Chemical Corporation, epoxy equivalent 800 to 900 g/eq)
(B1)-3: Dicyclopentadiene type epoxy resin (manufactured by DIC "Epiclon HP-7200HH", epoxy equivalent 255 to 260 g/eq)
・Heat curing agent (B2)
(B2)-1: Dicyandiamide ("ADEKA Hardener EH-3636AS" manufactured by ADEKA, heat-activated latent epoxy resin curing agent, active hydrogen content 21 g/eq)
・Curing accelerator (C)
(C)-1: 2-phenyl-4,5-dihydroxymethylimidazole (“Curesol 2PHZ-PW” manufactured by Shikoku Kasei Kogyo Co., Ltd.)
・ Filler (D)
(D)-1: Silica filler (“SC2050MA” manufactured by Admatechs, silica filler surface-modified with an epoxy-based compound, average particle size 0.5 μm)
・Coupling agent (E)
(E)-1: 3-Aminopropyltrimethoxysilane ("A-1110" manufactured by NUC)
・ Coloring agent (I)
(I)-1: Black pigment (manufactured by Dainichi Seika Co., Ltd.)

[Example 1]
<Manufacturing of support sheet>
(Production of adhesive composition (I-4))
Acrylic polymer (100 parts by mass, solid content), and a trifunctional xylylene diisocyanate-based cross-linking agent ("Takenate D110N" manufactured by Mitsui Takeda Chemicals Co., Ltd.) (40 parts by mass (solid content)), and methyl ethyl ketone as a solvent. , a mixed solvent of toluene and ethyl acetate, and a non-energy ray-curable pressure-sensitive adhesive composition (I-4) having a solid content concentration of 30% by mass was produced. The acrylic polymer is prepared by copolymerizing 2-ethylhexyl acrylate (2EHA) (80 parts by mass) and 2-hydroxylethyl acrylate (HEA) (20 parts by mass) and having a weight average molecular weight of 800,000. It is a copolymer.

(Manufacturing of support sheet)
Using a release film ("SP-PET381031" manufactured by Lintec Co., Ltd., thickness 38 μm) in which one side of a polyethylene terephthalate film is release-treated by silicone treatment, the pressure-sensitive adhesive composition obtained above is applied to the release-treated surface ( I-4) was applied and dried by heating at 120° C. for 2 minutes to form a non-energy ray-curable pressure-sensitive adhesive layer. At this time, the pressure-sensitive adhesive composition (I-4) was applied by setting the conditions so that the thickness of the pressure-sensitive adhesive layer was 4 μm.

One surface of a polypropylene film (manufactured by Mitsubishi Plastics Co., Ltd., thickness 80 μm) is pressed by rotating the uneven surface of a metal roll while heating, so that one surface is uneven and the other surface is smooth. A substrate having a surface (glossy surface) was produced. The maximum height roughness (Rz) of the uneven surface of this base material was measured according to JIS B 0601:2013 and found to be 5 μm.

Next, by bonding the uneven surface of the substrate to the exposed surface of the adhesive layer obtained above, the substrate, the adhesive layer and the release film are laminated in this order in the thickness direction. A support sheet was obtained. The width of the obtained support sheet (in other words, the width of the substrate and the pressure-sensitive adhesive layer) was 400 mm.
As described above, the support sheet of the present invention was obtained.

Next, this support sheet was immediately evaluated for the non-bonding region between the substrate and the pressure-sensitive adhesive layer, which will be described later. In addition, this support sheet was used as it was for manufacturing a composite sheet for forming a protective film, which will be described later.

<Production of composite sheet for forming protective film>
(Production of protective film-forming composition (III-1))
Polymer component (A)-1 (150 parts by mass), thermosetting component (B1)-1 (60 parts by mass), (B1)-2 (10 parts by mass), (B1)-3 (30 parts by mass) , (B2) -1 (2 parts by mass), curing accelerator (C) -1 (2 parts by mass), filler (D) -1 (320 parts by mass), coupling agent (E) -1 (2 parts by mass part), and coloring agent (I)-1 (18 parts by mass) were dissolved or dispersed in a mixed solvent of methyl ethyl ketone, toluene and ethyl acetate, and stirred at 23° C. to obtain a solid concentration of 51% by mass. A thermosetting protective film-forming composition (III-1) was obtained. In addition, all the compounding amounts shown here are solid content amounts.

(Production of film for forming protective film)
Using a release film (second release film, “SP-PET381031” manufactured by Lintec Co., Ltd., thickness 38 μm) in which one side of a polyethylene terephthalate film is release-treated by silicone treatment, the release-treated surface is coated with a knife coater. A thermosetting protective film-forming film having a thickness of 25 μm was produced by applying the protective film-forming composition (III-1) obtained above and drying at 100° C. for 2 minutes.

Furthermore, the exposed surface of the obtained film for forming a protective film on the side not provided with the second release film is treated with a release film (first release film, “SP-PET381031” manufactured by Lintec Corporation, thickness 38 μm). By bonding the surfaces together, a laminated film was obtained in which one surface of the film for forming a protective film was provided with the first release film and the other surface was provided with the second release film. The width of the obtained laminated film (in other words, the width of the protective film-forming film, the first release film and the second release film) was 400 mm.

(Manufacture of Composite Sheet for Protective Film Formation)
A pair of rolls (two rolls) having a diameter of 5 cm and having a depth of 3 mm from the surface of the rolls made of heat-resistant silicone rubber having a hardness of 50 degrees was prepared.
The release film was removed from the adhesive layer of the support sheet obtained above. Also, the first release film was removed from the laminated film obtained above.
Then, the exposed surface of the pressure-sensitive adhesive layer produced by removing the release film and the exposed surface of the protective film forming film produced by removing the first release film are faced to each other, and these support sheets and protective A film-forming film is superimposed to form a laminate, and this laminate is passed at a speed of 0.3 m/min through the gap between these rolls whose temperature is set to 60 ° C., thereby increasing the pressure to 0.5 MPa. It was heat-pressed (heat lamination) at a pressure of . As a result, the substrate, the pressure-sensitive adhesive layer, the protective film-forming film, and the second release film are laminated in this order in the thickness direction, which is the same laminated structure as the intended composite sheet for forming a protective film. A laminated sheet (composite sheet for forming a protective film before storage) was produced.
In the laminated sheet obtained, the width (in other words, the width of the support sheet) was 400 mm, and the outer diameter of the protective film-forming film was 330 mm.

Next, the laminated sheet having an overall size of 400 mm × 50 m obtained above is taken with the longitudinal direction as the winding direction, the winding tension is 160 N / m, the winding speed is 50 m / min, and the taper rate of the winding tension is At 90% condition, it was wound around an ABS resin core and wound into a roll. At this time, the laminated sheet was wound up with the substrate facing outward in the radial direction of the roll (in other words, the second release film was brought into contact with the core).
Then, this roll-shaped laminated sheet was stored at rest for 7 days (168 hours) under an air atmosphere at a temperature of 60°C.
As described above, a protective film-forming composite sheet of the present invention having the structure shown in FIG. 2 was obtained.

Next, the following items were evaluated for the protective film-forming composite sheet of the present invention after storage under such heating and pressurizing conditions.

<Evaluation of support sheet and protective film-forming composite sheet>
(Measurement of thickness of adhesive layer)
Test pieces each having a size of 3 mm×3 mm were cut out from five portions of the composite sheet for forming a protective film obtained above. These five cut-out positions correspond to one position corresponding to the central part of the circular protective film forming film and a position near the peripheral edge, which is substantially point symmetrical with respect to the central part. 4 places. Of these five cutout positions, the center-to-center distance between one corresponding to the central portion and the other four portions near the periphery was 100 mm.

Using a cross-sectional sample preparation device ("Cross Section Polisher SM-09010" manufactured by JEOL), the intermittent shutter conditions were set to "in" 10 seconds and "out" 5 seconds, the ion source voltage was set to 3 kV, and the total polishing time was was set to 24 hours, and the cross section was formed from the test piece. Only one cross section was newly formed for each test piece.

Scanning electron microscopy (SEM) was used to observe the newly formed cross-sections of these five specimens to determine the minimum and maximum adhesive layer thickness for each specimen. The observation area of the cross section of the test piece at this time was a 1 mm area in the width direction of the cross section.
Then, the average value of these minimum values was adopted as the S value of the pressure-sensitive adhesive layer, and the average value of these maximum values was adopted as the L value of the pressure-sensitive adhesive layer. Table 1 shows the results.

(Evaluation of lamination property between pressure-sensitive adhesive layer and film for forming protective film)
The composite sheet for forming a protective film obtained above is irradiated with light from the outside on the substrate side, and the presence or absence of a non-bonded region between the pressure-sensitive adhesive layer and the film for forming a protective film is determined. It was visually confirmed from the outside of the substrate through the support sheet. At this time, the visual confirmation was performed over the entire formation area of the protective film-forming film in the protective film-forming composite sheet.
Then, the degree of lamination between the pressure-sensitive adhesive layer and the film for forming a protective film was evaluated according to the following criteria. Table 1 shows the results.
A: There is no non-bonded area.
B: There are non-bonded areas, but the number is 3 or less.
C: There are four or more non-bonded regions.

(Evaluation of print visibility of protective film)
The second release film was removed from the composite sheet for forming a protective film obtained above, and the exposed surface of the film for forming a protective film thus produced (the surface opposite to the adhesive layer side) was placed on an 8-inch semiconductor sheet. Affixed to the back surface of the wafer. The sticking at this time was performed using a tape mounter (“RAD2700” manufactured by Lintec Corporation). As a result, a first laminated structure was produced in which the substrate, the pressure-sensitive adhesive layer, the film for forming a protective film, and the semiconductor wafer were laminated in this order in the thickness direction.

Next, using a laser printer ("CSM300M" manufactured by EO Technics), of the film for forming a protective film in the first laminated structure, on the adhesive layer side surface (second surface), via a support sheet. Printing was performed by irradiating a laser beam on the substrate. At this time, characters having a size of 0.3 mm×0.2 mm were printed.

Next, printing (laser printing) on this protective film-forming film was visually observed through the support sheet, and the visibility of the printing (characters) was evaluated according to the following criteria. Table 1 shows the results. The print visibility of the protective film-forming film evaluated here can be considered to be equal to the print visibility of the protective film.
A: The print is clear and easily visible.
B: The print is slightly blurred and not easily visible.
C: Print is unclear and invisible.

Then, the support sheet (substrate and pressure-sensitive adhesive layer) was peeled off from the protective film-forming film. Then, using an optical microscope (manufactured by KEYENCE CORPORATION), the line thickness of the print (character) formed on the film for forming a protective film was measured. As a result, the line thickness was 40 μm or more, and the printing was clear.

(Presence or absence of non-bonded area between base material and pressure-sensitive adhesive layer, and evaluation of interlayer distance)
Using a scanning electron microscope (SEM, "VE-9700" manufactured by Keyence Corporation), the composite sheet for forming a protective film obtained above was examined for the presence or absence of a non-bonded region between the substrate and the adhesive layer. confirmed. Then, when there was a non-bonded area, the interlayer distance was measured. The confirmation and measurement at this time were performed over the entire area of the substrate and the pressure-sensitive adhesive layer.
When measuring this interlayer distance, a cross section is formed in the protective film-forming composite sheet in the same manner as in the case of the test piece described above, and the interlayer distance between the substrate and the adhesive layer is measured in this cross section. It was measured.
Then, the non-bonding region between the substrate and the pressure-sensitive adhesive layer was evaluated according to the following criteria. Table 1 shows the results.
A: There is no non-bonded area.
B: Although there is a non-bonding area, the interlayer distance is 0.5 μm or less.
C: There is a non-bonded region, and the interlayer distance is greater than 0.5 μm.

(Presence or absence of a non-bonded region between the adhesive layer and the film for forming a protective film, and evaluation of the interlayer distance)
At the time of the evaluation of the non-bonding region between the base material and the adhesive layer, the presence or absence of the non-bonding region between the pressure-sensitive adhesive layer and the protective film-forming film was checked at the same time. Then, when there was a non-bonded area, the interlayer distance was measured. The confirmation and measurement at this time were carried out over the entire formation area of the protective film-forming film in the protective film-forming composite sheet.
When measuring this interlayer distance, a cross section is formed in the protective film-forming composite sheet in the same manner as in the case of the test piece described above, and in this cross section, the gap between the adhesive layer and the protective film-forming film is measured. The interlayer distance was measured.
Then, the non-bonding region between the pressure-sensitive adhesive layer and the protective film-forming film was evaluated according to the following criteria. Table 1 shows the results.
A: There is no non-bonded area.
B: Although there is a non-bonding area, the interlayer distance is 0.5 μm or less.
C: There is a non-bonded region, and the interlayer distance is greater than 0.5 μm.

(Evaluation of unevenness of second surface of film for forming protective film)
The second release film was removed from the composite sheet for forming a protective film obtained above, and the exposed surface of the resulting film for forming a protective film (the surface opposite to the pressure-sensitive adhesive layer side, the first surface) was It was attached to the back surface of an 8-inch semiconductor wafer (thickness: 200 μm). The sticking at this time was performed using a tape mounter (“RAD2700” manufactured by Lintec Corporation). As a result, a first laminated structure was produced in which the substrate, the pressure-sensitive adhesive layer, the film for forming a protective film, and the semiconductor wafer were laminated in this order in the thickness direction.
Next, the state of the adhesive layer side surface (second surface) of the protective film-forming film attached to the semiconductor wafer was visually confirmed through the support sheet and evaluated according to the following criteria. Table 1 shows the results.
The unevenness of the second surface of the film for forming a protective film evaluated here can be regarded as equal to the unevenness of the surface (second surface) of the protective film opposite to the semiconductor wafer side.
A: It is smooth or has extremely small unevenness, and the appearance of the film for forming a protective film is not impaired.
B: Partially uneven and not smooth, but the unevenness is extremely small, and the appearance of the film for forming a protective film is not impaired.
C: The degree of unevenness is large, and the appearance of the film for forming a protective film is impaired.

<Production of Supporting Sheet and Composite Sheet for Forming Protective Film, and Evaluation of Supporting Sheet and Composite Sheet for Forming Protective Film>
[Example 2]
Support was obtained in the same manner as in Example 1, except that the pressure-sensitive adhesive composition (I-4) was applied by setting the conditions so that the thickness of the pressure-sensitive adhesive layer was 5 μm instead of 4 μm. Sheets were manufactured and evaluated.
Then, a composite sheet for forming a protective film was produced and evaluated in the same manner as in Example 1, except that such a support sheet was used.
Table 1 shows the results.

[Example 3]
Support was obtained in the same manner as in Example 1, except that the pressure-sensitive adhesive composition (I-4) was applied by setting the conditions so that the thickness of the pressure-sensitive adhesive layer was 6 μm instead of 4 μm. Sheets were manufactured and evaluated.
Then, a composite sheet for forming a protective film was produced and evaluated in the same manner as in Example 1, except that such a support sheet was used.
Table 1 shows the results.

[Comparative Example 1]
Support was obtained in the same manner as in Example 1, except that the pressure-sensitive adhesive composition (I-4) was applied by setting the conditions so that the thickness of the pressure-sensitive adhesive layer was 3 μm instead of 4 μm. Sheets were manufactured and evaluated.
Then, a composite sheet for forming a protective film was produced and evaluated in the same manner as in Example 1, except that such a support sheet was used.
Table 1 shows the results.

[Comparative Example 2]
One surface of a polypropylene film (manufactured by Mitsubishi Plastics Co., Ltd., thickness 80 μm) is pressed by rotating the uneven surface of a metal roll while heating, so that one surface is uneven and the other surface is smooth. A substrate having a surface (glossy surface) was produced. The uneven surface of the metal roll used at this time had a greater degree of unevenness than the uneven surface of the metal roll used in Example 1. The maximum height roughness (Rz) of the uneven surface of the obtained base material was measured according to JIS B 0601:2013 and found to be 8 μm.

The point that the substrate obtained above was used, and the pressure-sensitive adhesive composition (I-4) was applied by setting the conditions so that the thickness of the pressure-sensitive adhesive layer was 7 μm instead of 4 μm, A support sheet was produced and evaluated in the same manner as in Example 1, except for the above.
Then, a composite sheet for forming a protective film was produced and evaluated in the same manner as in Example 1, except that such a support sheet was used.
Table 1 shows the results.

As is clear from the above results, in Examples 1 to 3, the S value of the pressure-sensitive adhesive layer is 2 μm or more (2 to 4 μm), and the lamination property between the pressure-sensitive adhesive layer and the film for forming a protective film is particularly excellent. rice field. Further, in these examples, the L value of the pressure-sensitive adhesive layer was 8 μm or less (6 to 8 μm), and the print visibility of the protective film (protective film-forming film) was particularly excellent.

On the other hand, in Comparative Example 1, the S value of the pressure-sensitive adhesive layer was 1 μm, and the pressure-sensitive adhesive layer had an extremely thin region. Therefore, a large number of non-bonded regions existed between the pressure-sensitive adhesive layer and the protective film-forming film, and the lamination property between the pressure-sensitive adhesive layer and the protective film-forming film was poor. Furthermore, due to the presence of such a non-bonding region, the visibility of printing on the protective film (protective film-forming film) through the support sheet was also poor.

In Comparative Example 2, the L value of the adhesive layer was 10 μm, and the adhesive layer had an extremely thick region. Therefore, the print visibility of the protective film (protective film-forming film) through the support sheet was poor.

In Examples 1 to 3, there was no non-bonded region between the base material and the adhesive layer and between the adhesive layer and the protective film-forming film. The interlayer distance was also small, and the composite sheet for forming a protective film had good properties.
In Examples 1 to 3, the second surface of the film for forming a protective film had a small degree of unevenness, the film for forming a protective film had an excellent appearance, and a highly designed protective film could be formed.

INDUSTRIAL APPLICABILITY The present invention can be used for manufacturing semiconductor devices.

1A, 1B, 1C... Composite sheet for forming protective film, 10... Supporting sheet, 10a... Surface (first surface) of supporting sheet on film side for forming protective film, 11... Base material, 11a... surface of the adhesive layer side of the substrate (first surface, uneven surface), 12... adhesive layer, 12a... surface opposite to the substrate side of the adhesive layer (first surface), 12b... surface (second surface) on the base material side of the adhesive layer, 13, 23... protective film-forming film, 13b... surface of the protective film-forming film on the adhesive layer side (Second surface), _{Ta: thickness of adhesive layer, Ta1 :} minimum thickness of adhesive layer, _Ta2 : maximum thickness of adhesive layer

Claims (3)

A composite sheet for forming a protective film, comprising a base material and a protective film-forming film on the pressure-sensitive adhesive layer in a support sheet comprising a pressure-sensitive adhesive layer on the base material,
The surface of the base material on the pressure-sensitive adhesive layer side is an uneven surface,
The maximum height roughness (Rz) of the uneven surface measured in accordance with JIS B 0601: 2013 is 5 to 8 μm,
Test pieces were cut out from five locations on the support sheet, and the minimum and maximum values of the thickness of the pressure-sensitive adhesive layer were obtained for each of these five test pieces. and the average value of the maximum values is 9 μm or less,
The film for forming a protective film is in direct contact with the adhesive layer,
Between the pressure-sensitive adhesive layer and the protective film-forming film, there is no non-bonding region where they are not bonded, or when the non-bonding region exists, the non-bonding region A composite sheet for forming a protective film, wherein the distance between the adhesive layer and the film for forming a protective film is 0.5 μm or less. The protective film-forming composite sheet according to claim 1, wherein the pressure-sensitive adhesive layer is in direct contact with the uneven surface of the substrate. Between the base material and the pressure-sensitive adhesive layer, there is no non-bonding region where they are not bonded, or when the non-bonding region exists, the base material in the non-bonding region 3. The composite sheet for forming a protective film according to claim 2, wherein the distance between the adhesive layer and the pressure-sensitive adhesive layer is 0.5 μm or less.

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