JP2020044696A - Release film, and method for producing electronic component assembly using the same - Google Patents

Abstract

To provide a release film that resists warping during heating, and a method for producing an electronic component assembly using the same.SOLUTION: A release film 50 has a resin layer (A), and a heat-resistant layer (B) provided on one side of the resin layer (A). The heat-resistant layer (B) has at least one layer selected from a metal layer (B2) and a resin layer (B1) having a smaller linear expansion coefficient than that of the resin layer (A). On the plane of the heat-resistant layer (B), formed are a plurality of slit parts 10.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a release film and a method for manufacturing an electronic component assembly using the same.

In the manufacturing process of an electronic device, an anisotropic conductive film (ACF: Anisotropic Conductive Film) or a non-conductive adhesive film (NCF: Non Conductive Adhesive Film) is used for the electronic device by using a film adhesive. There is a process of electrically connecting components (hereinafter, also referred to as electronic components) such as a semiconductor chip and a substrate by heat compression.
The adhesive such as ACF and NCF contains a thermosetting resin such as an epoxy resin. When an adhesive is placed between two electronic components and the electronic components are heated and pressed together, the thermosetting resin contained in the adhesive is cured by heat, and the electronic components can be joined together.
Here, in the step of thermocompression bonding the electronic components, the melted ACF or NCF may protrude and adhere to the heating head. Therefore, generally, a release film is disposed between a heating head unit for heating and pressing and an electronic component.

  As a technique relating to such a release film, for example, a technique described in Patent Document 1 (Japanese Patent Application Laid-Open No. 2007-296727) is exemplified.

  Patent Literature 1 describes a release sheet having a glass fiber layer and a release layer containing a fluororesin, wherein one main surface of the release layer is exposed.

JP 2007-296727 A

According to the study of the present inventor, in a state where a release film having a release layer and a heat-resistant layer is disposed between a heating head portion and an electronic component, when the electronic components are heat-pressed, the release is performed by heating. It has become clear that the film may be significantly warped. If the release film is greatly warped, there is a concern that, for example, the adhesive disposed between the two electronic components may flow around the heat-resistant layer side of the release film.
The present invention has been made in view of the above circumstances, and provides a release film in which warpage during heating is suppressed. The present invention also provides a method for manufacturing an electronic component assembly using a release film in which warpage during heating is suppressed.

  The present inventors have conducted intensive studies to achieve the above object. As a result, it has been found that by providing a plurality of slits on the surface of the release film, it is possible to suppress the warpage of the release film when heating is performed, and completed the present invention.

  According to the present invention, a release film described below and a method for manufacturing an electronic component assembly using the same are provided.

[1]
A resin layer (A),
A release film comprising a heat-resistant layer (B) provided on one surface of the resin layer (A),
The heat-resistant layer (B) includes at least one layer selected from a resin layer (B1) and a metal layer (B2) having a smaller linear expansion coefficient than the resin layer (A),
A release film in which a plurality of slits are formed in the plane of the heat-resistant layer (B).
[2]
In the release film according to the above [1],
A release film in which the plurality of slits are formed uniformly over the entire surface of the heat-resistant layer (B).
[3]
In the release film according to the above [1] or [2],
A release film in which at least a part of the plurality of slit portions is formed in a pattern on the surface of the heat-resistant layer (B).
[4]
The release film according to any one of the above [1] to [3],
A release film in which the resin layer (A) has release properties.
[5]
The release film according to the above [4],
A release film in which the resin layer (A) contains a fluorine-based resin.
[6]
The release film according to any one of [1] to [5],
A release film in which the resin layer (B1) contains a heat-resistant resin.
[7]
The release film according to the above [6],
The heat-resistant resin has a softening point, a glass transition temperature, or a melting point of 200 ° C. or more, or the heat-resistant resin has no softening point, a glass transition temperature, or a melting point.
[8]
In the release film according to the above [7],
The heat-resistant resin is polyester, polyamide, polyimide, polyetherimide, polyamideimide, polycarbonate, modified polyphenylene ether, polyacetal, polyarylate, polysulfone, polyethersulfone, polyphenylene sulfide, polyetheretherketone, liquid crystal polymer, vinylidene chloride resin, A release film containing at least one selected from polybenzimidazole, polybenzoxazole, polymethylpentene, and silicone resin.
[9]
The release film according to any one of the above [1] to [8],
A release film in which the metal layer (B2) contains one or more metals selected from the group consisting of aluminum, copper, stainless steel, tin, titanium alloy, nickel alloy, aluminum bronze, gold and silver.
[10]
The release film according to any one of the above [1] to [9],
The average linear thermal expansion coefficient in the plane direction (XY direction) of the resin layer (A) calculated in the range of 50 ° C to 200 ° C is 30 ppm / ° C or more;
A release film having an average linear thermal expansion coefficient of 90 ppm / ° C. or less in the plane direction (XY directions) calculated in the range of 50 ° C. to 200 ° C. of the heat-resistant layer (B).
[11]
In the release film according to any one of the above [1] to [10],
A release film that is in the form of a film or sheet.
[12]
The release film according to any one of [1] to [11],
A release film in which the depth of the slit is not less than the thickness of the heat-resistant layer (B) and less than the thickness of the release film.
[13]
In the release film according to any one of the above [1] to [12],
A release film in which the longest interval among the intervals between the adjacent slit portions is 0.05 mm or more and 20 mm or less.
[14]
The release film according to any one of the above [1] to [13],
A release film in which the heat-resistant layer (B) is heated by a heat source.
[15]
In the release film according to any one of the above [1] to [14],
A release film that is a release film used in a step of heating and pressing electronic components together in a manufacturing process of an electronic device.
[16]
The release film according to any one of the above [1] to [14] is provided between the electronic component B disposed on the electronic component A via the film adhesive and the heating head and the heat-resistant layer. A step of joining the electronic component A and the electronic component B by pressing the electronic component B toward the electronic component A with the heating head in a state where (B) is arranged so as to face the heating head. And a method for manufacturing an electronic component assembly.

  ADVANTAGE OF THE INVENTION According to this invention, the release film in which the curvature at the time of heating was suppressed, and the manufacturing method of the electronic component assembly using the same can be provided.

It is sectional drawing which showed typically an example of the structure of the release film of embodiment which concerns on this invention. It is the top view which showed typically an example of the shape of the slit part in the release film of embodiment which concerns on this invention. It is the top view which showed typically an example of the shape of the slit part in the release film of embodiment which concerns on this invention. It is sectional drawing which showed typically an example of the structure of the release film of embodiment which concerns on this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, similar components are denoted by common reference numerals, and description thereof will not be repeated. Also, the figure is a schematic view, and does not match the actual dimensional ratio. Further, “A to B” in the numerical range represents A to B, unless otherwise specified.

1. Release Film Hereinafter, the release film 50 according to the present embodiment will be described.
FIG. 1 is a cross-sectional view schematically illustrating an example of the structure of a release film 50 according to an embodiment of the present invention.

  As shown in FIG. 1, the release film 50 according to the present embodiment is a release film including a resin layer (A) and a heat-resistant layer (B) provided on one surface of the resin layer (A). The heat-resistant layer (B) includes at least one layer selected from a resin layer (B1) and a metal layer (B2) having a smaller coefficient of linear expansion than the resin layer (A). A plurality of slits 10 are formed.

According to the study of the present inventor, in a state where a release film having a release layer and a heat-resistant layer is disposed between a heating head portion and an electronic component, when the electronic components are heat-pressed, the release is performed by heating. It has become clear that the film may be significantly warped. If the release film is significantly warped, the release film will be twisted during transport, causing the release film to shift from the top of the electronic component before being pinched by the heating head, or the release film to be placed in unnecessary locations. There is a concern that the touch panel may be touched, and that the adhesive disposed between the two electronic components may reach the heat-resistant layer side of the release film.
Although the reason why the release film having the release layer and the heat-resistant layer is greatly warped is not clear, the following reasons are considered. Since there is a difference in linear expansion coefficient between the release layer and the heat-resistant layer, a large difference occurs between the thermal stress applied to the heat-resistant layer by the release layer and the thermal stress applied to the release layer by the heat-resistant layer. I will. Therefore, when the release film is heated, it is considered that the release film is largely warped due to a difference between a thermal stress applied to the heat-resistant layer by the release layer and a thermal stress applied to the release layer by the heat-resistant layer.
Therefore, the present inventors have conducted intensive studies in order to realize a release film in which warpage during heating is suppressed. As a result, by forming the plurality of slits 10 in the plane of the heat-resistant layer (B) on the side where the linear expansion coefficient is relatively small, the slits 10 of the heat-resistant layer (B) extend to become a release layer. The heat-resistant layer (B) can follow the thermal expansion of the resin layer (A), and the thermal stress on the heat-resistant layer (B) due to the resin layer (A) is reduced. We have found for the first time that warpage can be suppressed.
That is, the release film 50 according to the present embodiment has a plurality of slit portions 10 in the plane of the heat-resistant layer (B) having a smaller linear expansion coefficient than the resin layer (A), thereby suppressing warpage during heating. It is possible to do.

FIG. 2 is a plan view schematically showing an example of the shape of the slit portion 10 in the release film 50 of the embodiment according to the present invention.
In the release film 50 according to the present embodiment, the plurality of slit portions 10 are preferably formed uniformly over the entire surface of the heat-resistant layer (B), as shown in FIG. By doing so, the heat-resistant layer (B) can follow the thermal expansion of the resin layer (A) over the entire surface of the release film 50, and the warpage of the release film 50 during heating can be further effectively reduced. Can be suppressed.

In the release film 50 according to the present embodiment, at least a part of the plurality of slit portions 10 is preferably formed in a pattern on the surface of the heat-resistant layer (B), as shown in FIG. By doing so, the heat-resistant layer (B) can follow the thermal expansion of the resin layer (A) over the entire surface of the release film 50, and the warpage of the release film 50 during heating can be further effectively reduced. Can be suppressed.
Here, the pattern shape is, for example, a pattern in which the same shape such as a striped shape, a grid shape, a mesh shape, a linear shape, a striped shape, a zigzag shape, and the like are repeatedly arranged side by side, and a gap is formed between adjacent patterns. Means a certain shape or arrangement. The plurality of pattern-shaped slit portions 10 are not particularly limited, and examples thereof include those shown in (a) to (g) of FIG.

In the release film 50 according to the present embodiment, as shown in FIG. 1, the depth of the slit portion 10 is not particularly limited, but may be not less than the thickness of the heat-resistant layer (B) and less than the thickness of the release film 50. preferable. When the depth of the slit portion 10 is equal to or greater than the thickness of the heat-resistant layer (B), the heat-resistant layer (B) can more effectively follow the thermal expansion of the resin layer (A), and the release film during heating 50 can be more effectively suppressed. In addition, when the depth of the slit portion 10 is less than the thickness of the release film 50 of the heat-resistant layer (B), it is possible to suppress the release film 50 from being scattered by the slit portion 10. Further, it is possible to prevent the adhesive or the like from entering the slit portion 10 of the release film 50.
For example, when the slit portion 10 is not formed up to the end of the release film 50 as shown in FIG. 3, even if the depth of the slit portion 10 reaches the thickness of the heat-resistant layer (B), it is released. Since the film 50 is not separated by the slit portion 10, the depth of the slit portion 10 may be the same as the thickness of the release film 50.

In the release film 50 according to the present embodiment, the longest interval among the intervals between the adjacent slit portions 10 is not particularly limited, but is, for example, 0.05 mm or more and 20 mm or less.
Further, in the release film 50 according to the present embodiment, the width of the gap (white portion in FIG. 2) of the slit portion 10 is not particularly limited, but the upper limit is preferably 2 mm or less.

In the release film 50 according to the present embodiment, the average linear expansion coefficient in the plane direction (XY direction) of the resin layer (A) calculated in the range of 50 ° C to 200 ° C is, for example, 30 ppm / ° C or more. The average linear expansion coefficient in the plane direction (XY directions) of the heat-resistant layer (B) calculated in the range of 50 ° C. to 200 ° C. is, for example, 90 ppm / ° C. or less.
The average linear expansion coefficient of the resin layer (A) is larger than the average linear expansion coefficient of the heat-resistant layer (B).
Although the upper limit of the average linear expansion coefficient in the plane direction (XY direction) calculated in the range of 50 ° C. to 200 ° C. of the resin layer (A) is not particularly limited, it is, for example, 200 ppm / ° C. or less.
The lower limit of the average linear expansion coefficient in the plane direction (XY direction) calculated in the range of 50 ° C. to 200 ° C. of the heat-resistant layer (B) is not particularly limited, but is, for example, 3 ppm / ° C. or more.
In the present embodiment, when the resin layer (A) and the heat-resistant layer (B) are each composed of two or more layers, the average linear expansion coefficient is the value of the resin layer (A) as a whole and the heat-resistant layer (B), respectively. Refers to the value as a whole.

  The thickness of the entire release film 50 according to the present embodiment is preferably 10 μm or more and 200 μm or less, more preferably 15 μm or more and 100 μm or less, and still more preferably 15 μm or more and 60 μm or less, from the viewpoint of balance between mechanical properties and handleability. It is.

  Although the shape of the release film 50 according to the present embodiment is not particularly limited, examples thereof include a film shape, a sheet shape, and a plate shape. Among them, a film or a sheet is preferable.

  The release film 50 according to the present embodiment can be suitably used, for example, as a release film used in a step of heating and pressing electronic components together in a manufacturing process of an electronic device. More specifically, the release film 50 according to the present embodiment is used in a method of manufacturing an electronic device when a semiconductor chip is stacked and bonded, or when a semiconductor chip is mounted on a substrate. It can be suitably used as a release film to be disposed between electronic components. Here, the type of the electronic component to be bonded is not particularly limited, and examples thereof include a semiconductor chip; a semiconductor wafer; various substrates such as a metal substrate and a glass substrate (electrodes may be provided on the substrate); , TCP (Tape Carrier Package), FPC (Flexible Printed Circuit), etc. (ICs may be provided on TCP or FPC); transparent conductive layers, such as ITO (Indium Tin Oxide) layer; Is mentioned.

  Next, each layer constituting the release film 50 according to the present embodiment will be described.

<Resin layer (A)>
The resin layer (A) is a layer having a larger linear expansion coefficient than the heat-resistant layer (B). The resin layer (A) preferably has mold release properties. When the release film 50 is used as a release film used in a step of heating and pressing electronic components together in a manufacturing process of an electronic device, the resin layer (A) is a layer disposed so as to face the electronic components. This is a layer provided to peel off the release film 50 from the electronic component after the electronic component is sealed and formed.
The resin layer (A) is not particularly limited, and examples thereof include a resin film.
Here, in the present embodiment, having releasability means, for example, a case where the contact angle with water is 80 ° or more.

The resin layer (A) preferably contains a fluorine-based resin from the viewpoint of improving the releasability.
Examples of the fluororesin constituting the resin layer (A) include PTFE (polytetrafluoroethylene), PVDF (polyvinylidene fluoride), PCTFE (polychlorotrifluoroethylene), PVF (polyvinyl fluoride), and PFA (tetrafluoroethylene). A copolymer of ethylene fluoride and perfluoroalkoxyethylene), FEP (copolymer of tetrafluoroethylene and hexafluoropropylene), ETFE (copolymer of tetrafluoroethylene and ethylene), ECTFE (ethylene and chloroethylene) Or one or more selected from copolymers with trifluoroethylene).
Among these, at least one fluorine-based resin selected from the group consisting of PTFE, PFA, and FEP is preferable from the viewpoint of excellent balance among heat resistance, unevenness followability, price, and the like.

The resin layer (A) may be a single layer or two or more layers.
Further, the resin layer (A) may have a form having a resin layer (A1) and a fluorine coat layer (A2), for example, as shown in FIG. In this case, the fluorine coat layer (A2) is a layer having releasability, and preferably contains the above-mentioned fluorine-based resin. The resin layer (A1) is not particularly limited, and may be a layer containing a known thermoplastic resin or thermosetting resin.
The fact that the resin layer (A) is formed of a resin layer (A1) containing a thermoplastic resin and a thermosetting resin, and a fluorine coat layer (A2) as a surface layer in contact with an electronic component, has irregularities absorbing and releasing properties. It is preferable from the viewpoint of achieving both.
Examples of the thermoplastic resin include, for example, polyphenylene sulfide, polysulfone, thermoplastic polyimide, amorphous polyarylate, liquid crystal polymer, polyetheretherketone, polyamideimide, and the like.As the thermosetting resin, for example, phenol Resins, urea resins, melamine resins, epoxy resins, unsaturated polyester resins, and the like.
From the viewpoint of improving the releasability, it is preferable to use the above-mentioned fluorine-based resin material for the fluorine coat layer (A2).
It is preferable that the resin layer (A1) is thickened, that is, “thickness of the resin layer (A1)> thickness of the fluorine coat layer (A2)” is satisfied from the viewpoint of the unevenness absorbability. In this case, since the influence of the thermal expansion of the resin layer (A1) is large, the resin layer (A1) has an average coefficient of linear expansion in the plane direction (XY directions) of 30 ppm / ° C. in the range of 50 ° C. to 200 ° C. This is preferable because the warpage of the release film 50 during heating is further suppressed.

The thickness of the resin layer (A) is preferably 1 μm or more and 100 μm or less, more preferably 1 μm or more and 50 μm or less, and still more preferably 5 μm or more and 40 μm or less, from the viewpoint of obtaining good unevenness followability.
The resin layer (A) may be subjected to a surface treatment in order to improve the adhesiveness with another layer. Specifically, a corona treatment, a plasma treatment, an undercoat treatment, a primer coat treatment, or the like may be performed.

<Heat-resistant layer (B)>
The heat-resistant layer (B) is at least one layer selected from a resin layer (B1) and a metal layer (B2) having a smaller linear expansion coefficient than the resin layer (A). The heat-resistant layer (B) has heat resistance. Further, when the release film 50 is used as a release film used in a step of heating and pressing electronic components together in a manufacturing process of an electronic device, the heat-resistant layer (B) side is heated by a heat source, that is, the heating head and The contact side is preferably.
Here, in this embodiment, heat resistance means dimensional stability and thermal decomposition stability at high temperatures. In other words, it means that a layer having higher heat resistance is less likely to undergo deformation such as expansion, contraction, and softening, melting, and decomposition at a high temperature.
The resin layer (B1) is not particularly limited, and examples thereof include a resin film.
The metal layer (B2) is not particularly limited, and examples thereof include a metal thin film.

The resin layer (B1) preferably contains a heat-resistant resin from the viewpoint of improving heat resistance.
Examples of the heat-resistant resin include polyester, polyamide, polyimide, polyetherimide, polyamideimide, polycarbonate, modified polyphenylene ether, polyacetal, polyarylate, polysulfone, polyethersulfone, polyphenylene sulfide, polyetheretherketone, liquid crystal polymer, and chloride. One or more selected from vinylidene resin, polybenzimidazole, polybenzoxazole, polymethylpentene, silicone resin and the like can be mentioned.
Among these, one or more selected from polyimide, polyamide, polyetheretherketone, and polyester are preferable from the viewpoint of excellent balance between heat resistance, mechanical strength, and price.

Any of the softening point, glass transition temperature and melting point of the heat-resistant resin is preferably 200 ° C. or more, more preferably 220 ° C. or more. Alternatively, the heat-resistant resin preferably does not have any of a softening point, a glass transition temperature and a melting point, more preferably has a decomposition temperature of 200 ° C or higher, and more preferably has a decomposition temperature of 220 ° C or higher. preferable.
When such a heat-resistant resin is used, the heat resistance of the heat-resistant layer (B) can be further improved.

The metal layer (B2) can include a metal thin film from the viewpoint of improving heat resistance.
The metal layer (B2) is, for example, a layer containing one or more metals selected from the group consisting of aluminum, copper, stainless steel, tin, titanium alloy, nickel alloy, aluminum bronze, gold, and silver.
Examples of the metal thin film include an aluminum film, a copper film, a stainless film, a tin film, a titanium alloy film, a nickel alloy film, an aluminum bronze film, a gold film, and a silver film.
The metal thin film can be formed by an evaporation method, a sputtering method, or the like. Further, a metal foil may be used as the metal thin film.

  The heat-resistant layer (B) may be a single layer or two or more layers.

When the heat-resistant layer (B) is a resin layer (B1) containing a resin, the thickness of the heat-resistant layer (B) is preferably 1 μm or more and 90 μm or less, more preferably 5 μm or more from the viewpoint of obtaining good film properties. It is 50 μm or less.
When the heat-resistant layer (B) is a metal layer (B2) containing a metal, the thickness of the heat-resistant layer (B) is preferably from 20 nm to 90 μm, and more preferably from 30 nm, from the viewpoint of heat resistance and film properties. It is 50 μm or less.
When the heat-resistant layer (B) is a resin layer (B1), a surface treatment may be performed to improve the adhesiveness with another layer. Specifically, a corona treatment, a plasma treatment, an undercoat treatment, a primer coat treatment, or the like may be performed.

<Other layers>
The release film 50 according to the present embodiment according to the present embodiment further includes, for example, an adhesive layer or the like between the resin layer (A) and the heat-resistant layer (B) as long as the effects of the present embodiment are not impaired. It may be. The adhesive layer is not particularly limited as long as it can firmly bond the resin layer (A) and the heat-resistant layer (B) and does not peel off in the step of heating and pressing the electronic components together or in the peeling step. When the adhesive layer is provided, the thickness of the adhesive layer is preferably smaller than that of the resin layer (A). The coefficient of linear expansion of the adhesive layer is preferably larger than the coefficient of linear expansion of the heat-resistant layer (B).

2. Method for Manufacturing Release Film The release film 50 according to the present embodiment can be obtained by, for example, co-extrusion molding and laminating the resin layer (A) and the heat-resistant layer (B). Further, the release film 50 according to the present embodiment can also be obtained by, for example, laminating (laminating) a film-shaped resin layer (A) and a film-shaped heat-resistant layer (B). Further, the release film 50 according to the present embodiment can also be obtained by, for example, coating the resin layer (A) on the film-like heat-resistant layer (B).
Alternatively, it can also be obtained by coating the resin layer (A) with a coating liquid to be the heat-resistant layer (B) and then heating.
Alternatively, it can be obtained by forming a heat-resistant layer (B) made of a metal thin film on the resin layer (A) by an evaporation method, a sputtering method, or the like.

3. Method for Manufacturing Electronic Component Assembly The release film 50 according to the present embodiment is suitable for use in manufacturing an electronic component assembly. Specifically, for example, a release film is placed between an electronic component B disposed on the electronic component A via a film adhesive such as an anisotropic conductive film or a non-conductive adhesive film, and a heating head. In a state where the electronic component B is pressed toward the electronic component A by the heating head in the arranged state, the electronic component A and the electronic component B are joined together. It is suitable to use the release film 50 according to the embodiment. Here, the heat-resistant layer (B) of the release film 50 is arranged facing the heating head.

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

  It should be noted that the present invention is not limited to the above-described embodiment, but includes modifications and improvements as long as the object of the present invention can be achieved.

  Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited thereto.

<Material>
The details of the materials used for producing the release film are as follows.

Resin layer A1-1: Polytetrafluoroethylene (PTFE) film (manufactured by Nitto Denko Corporation, product name: No. 900UL, thickness: 30 μm, average in plane direction (XY direction) calculated in the range of 50 ° C to 200 ° C) Coefficient of linear expansion: 130 ppm / ° C)
Resin layer A1-2: Thermoplastic polyimide film (manufactured by Kurabo Industries, product name: Midfil NS, thickness: 25 μm, average linear expansion coefficient in the plane direction (XY direction) calculated from 50 ° C to 200 ° C: 55 ppm / ℃)
Resin layer A1-3: Polyetheretherketone film (manufactured by Kurabo Industries, product name: EXPEK, thickness: 25 μm, average linear expansion coefficient in the plane direction (XY direction) calculated in the range of 50 ° C. to 200 ° C .: 41 ppm / ℃)
Resin layer A2-1: Fluorinated resin (Fluoro Technology Co., Ltd., product name: Fluorosurf, 0.1% by mass solution)
Heat-resistant layer B-1: Kapton pressure-sensitive adhesive tape (manufactured by AS ONE Corporation, product name: KS-100055, thickness: 55 µm (including pressure-sensitive layer), average linear expansion in the plane direction (XY direction) calculated in the range of 50 ° C to 200 ° C (Coefficient: 15 ppm / ° C, melting point: none)
Heat-resistant layer B-2: polyimide film (film formed from varnish B1 described below)
Method for preparing varnish B1: Pyromellitic dianhydride and 4,4′-diaminodiphenyl ether are polymerized in dimethylacetamide by a generally known method such as Japanese Patent No. 4957487 to obtain a polyamic acid varnish (varnish). B1) was obtained.
When a polyimide film having a thickness of 10 μm after coating was prepared using the obtained varnish B1, the obtained polyimide film was obtained in the plane direction (XY direction) calculated in the range of 50 ° C. to 200 ° C. The average coefficient of linear expansion was 27 ppm / ° C. Further, the melting point of the obtained polyimide film was not observed.

[Example 1]
The heat-resistant layer B-1 was attached to the resin layer A1-1 with a hand roller. Then, it was cured at 40 ° C. for 24 hours. The Kapton film layer of the Kapton pressure-sensitive adhesive tape was cut at an interval of 1 mm in parallel with the tape width direction with a cutter knife to form a slit, and a release film 1 was obtained.
The following evaluation was performed about the obtained release film 1. Table 1 shows the obtained results.

[Example 2]
A release film 2 was obtained in the same manner as in Example 1 except that the interval between the slits was 5 mm.

[Example 3]
A polyamic acid varnish (varnish B1) was applied to the resin layer A1-2 and heated at 240 ° C. for 1 hour to obtain a laminated film of the resin layer A1-2 and the heat-resistant layer B-2. Thereafter, a fluororesin (a product of Fluoro Technology Co., Ltd., product name: Fluorosurf, 0.1% by mass solution) is applied with a brush to the surface of the resin layer A1-2 on which the heat-resistant layer B-2 is not formed. And dried at 130 ° C. for 15 minutes to form a resin layer A2-1. Thereafter, slits were formed in the heat-resistant layer B-2 at intervals of 1 mm with a cutter knife to form a release film 3.
A cross section of the release film 3 was observed with a transmission electron microscope (TEM) (manufactured by Hitachi, Ltd.) at a magnification of 200000, but the thickness could not be measured because the resin layer A2-1 was thin.
When the elements on the surface on which the resin layer A2-1 was formed were measured by X-ray photoelectric spectroscopy (XPS) using AXIS-NOVA manufactured by KRATOS, a fluorine element was confirmed. Therefore, although the absolute value of the thickness was unknown, it was confirmed that the resin layer A2-1 was present.

[Example 4]
A release film 4 was obtained in the same manner as in Example 3 except that the resin layer A1-3 was used instead of the resin layer A1-2.

[Comparative Examples 1 to 3]
Release films 5 to 7 were obtained in the same manner as in Example 1 except that the layer structure of the release film was changed to the layer configuration shown in Table 1, and that no slit portion was formed in the plane of the heat-resistant layer (B). The following evaluation was performed about the obtained release films 5-7. Table 1 shows the obtained results.

<Evaluation>
(1) Measurement of linear expansion coefficient of resin layer (A) and heat-resistant layer (B) Test pieces of 4 mm × 25 mm were prepared from the resin layer (A) and the heat-resistant layer (B). About the obtained test piece, using a thermomechanical analyzer TMA (manufactured by Seiko Instruments Inc., product name: SS6100), conditions of a temperature range of 30 to 300 ° C., a heating rate of 10 ° C./min, a load of 5 g, and a tensile mode condition Was used to measure thermomechanical analysis (TMA). From the obtained results, the average linear expansion coefficients of the resin layer (A) and the heat-resistant layer (B) in the plane direction (XY directions) in the range of 50 ° C to 200 ° C were calculated.

(2) Warpage of release film after heat treatment The release films obtained in Examples and Comparative Examples were cut into 1 cm x 5 cm pieces and placed on a hot plate so that the heat-resistant layer (B) side was down. At 300 ° C. for 60 seconds. Next, the heat-treated release film was placed on a horizontal table and cooled to room temperature. When one end was pressed against the table, the distance of the other end from the table was measured.

  The release film of the example in which a plurality of slits were formed in the plane of the heat-resistant layer (B) was warped during heating, and the release film of the comparative example in which the slit was not formed in the plane of the heat-resistant layer (B). It was suppressed more than the release film.

A Resin layer B Heat resistant layer A1 Resin layer A2 Fluorine coat layer 10 Slit part 50 Release film

Claims (16)

A resin layer (A),
A release film including a heat-resistant layer (B) provided on one surface of the resin layer (A),
The heat-resistant layer (B) includes at least one layer selected from a resin layer (B1) and a metal layer (B2) having a smaller linear expansion coefficient than the resin layer (A),
A release film having a plurality of slits formed in a plane of the heat-resistant layer (B). The release film according to claim 1,
The release film, wherein the plurality of slits are formed uniformly over the entire surface of the heat-resistant layer (B). The release film according to claim 1 or 2,
A release film in which at least a part of the plurality of slit portions is formed in a pattern on the surface of the heat-resistant layer (B). The release film according to any one of claims 1 to 3,
A release film in which the resin layer (A) has release properties. The release film according to claim 4,
A release film in which the resin layer (A) contains a fluorine-based resin. The release film according to any one of claims 1 to 5,
A release film in which the resin layer (B1) contains a heat-resistant resin. The release film according to claim 6,
The heat-resistant resin has a softening point, a glass transition temperature, and a melting point of 200 ° C. or higher, or the heat-resistant resin has no softening point, a glass transition temperature, or a melting point. The release film according to claim 7,
The heat-resistant resin is polyester, polyamide, polyimide, polyetherimide, polyamideimide, polycarbonate, modified polyphenylene ether, polyacetal, polyarylate, polysulfone, polyethersulfone, polyphenylene sulfide, polyetheretherketone, liquid crystal polymer, vinylidene chloride resin, A release film containing at least one selected from polybenzimidazole, polybenzoxazole, polymethylpentene, and silicone resin. The release film according to any one of claims 1 to 8,
A release film in which the metal layer (B2) contains one or more metals selected from the group consisting of aluminum, copper, stainless steel, tin, titanium alloy, nickel alloy, aluminum bronze, gold and silver. The release film according to any one of claims 1 to 9,
The average linear thermal expansion coefficient in the plane direction (XY direction) of the resin layer (A) calculated in the range of 50 ° C to 200 ° C is 30 ppm / ° C or more;
A release film having an average linear thermal expansion coefficient of 90 ppm / ° C. or less in a plane direction (XY directions) calculated in a range of 50 ° C. to 200 ° C. of the heat-resistant layer (B). The release film according to any one of claims 1 to 10,
A release film that is in the form of a film or sheet. The release film according to any one of claims 1 to 11,
A release film wherein the depth of the slit portion is equal to or greater than the thickness of the heat-resistant layer (B) and less than the thickness of the release film. The release film according to any one of claims 1 to 12,
A release film in which the longest interval among the intervals between the adjacent slit portions is 0.05 mm or more and 20 mm or less. The release film according to any one of claims 1 to 13,
A release film in which the heat-resistant layer (B) side is a side heated by a heat source. The release film according to any one of claims 1 to 14,
A release film that is a release film used in a step of heating and pressing electronic components together in a manufacturing process of an electronic device.   The release film according to any one of claims 1 to 14, wherein the heat-resistant layer (B) is provided between an electronic component B disposed on the electronic component A via a film adhesive and a heating head. And pressing the electronic component B toward the electronic component A with the heating head in a state where the electronic component A faces the heating head, thereby joining the electronic component A and the electronic component B. Manufacturing method of electronic component assembly.

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