Release film

Abstract

To provide a release film which can obtain a molding having good appearance while improving workability of the release film.SOLUTION: A release film 10 has a multilayer structure formed by laminating a release layer 1, a first base material layer 3, and a second base material layer 2 in this order. The release layer 1 constitutes a release surface 11 of the release film 10, the second base material layer 2 constitutes a surface 21 of the release film 10 on a side opposite to the release surface 11. The release layer 1 contains one or two or more kinds selected from a silicone resin, a fluororesin, a melamine resin, an epoxy resin, and a phenol resin. The first base material layer 3 is formed of a stretched or non-stretched film containing one or two or more kinds selected from a polyester resin, a polyolefin resin, and a polyamide resin. The second base material layer 2 is formed of a stretched or non-stretched film containing one or two or more kinds selected from a polyester resin, a polyolefin resin, and a polyamide resin.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a release film. [Background technology]

[0002] Various technologies have been developed in the field of release films. For example, in the field of semiconductor device manufacturing processes, it is known to produce molded articles by placing a release film between a mold and an object to be molded, and then resin-encapsulating the object, on which electronic components such as semiconductor elements are mounted, using molding techniques such as transfer molding or compression molding (e.g., Patent Documents 1 to 3). By placing a release film between the mold and the object to be molded, the molded article can be easily removed from the mold after resin encapsulation. Furthermore, release films used in resin molding using such molds are also generally referred to as mold-molding release films. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-151949 [Patent Document 2] Japanese Patent Publication No. 2020-19264 [Patent Document 3] Japanese Patent Application Publication No. 2016-092272 Summary of the Invention [Problem to be solved by the invention]

[0004] However, wrinkles and distortions that occur in the release film may be transferred to the surface of molded articles obtained using conventional release films, and there is room for improvement in terms of obtaining molded articles with a higher level of appearance. [Means for solving the problem]

[0005] The present inventors have conducted extensive research into the causes of wrinkles and distortions occurring in release films and have found the following problems. Typically, a suction port for vacuum exhaust is provided around the cavity recess of the lower mold to vacuum-adhere the release film to the inner surface of the cavity recess. After the release film is placed so as to cover both the cavity recess and the suction port around it, the air between the release film and the cavity recess is sucked through the suction port, and the release film is vacuum-adhered to the inner surface of the cavity recess. During this vacuum exhaust, the release film is also drawn into the suction port to some extent. However, if the amount of deformation of the release film is insufficient, a portion of the release film may be drawn into the suction port, causing the edge of the release film near the suction port to stand up. As a result, a small gap is formed between the raised edge of the release film and the lower mold, preventing sufficient suction, which reduces the adhesion of the release film to the cavity recess and makes the release film more susceptible to wrinkles. The upper mold holds a molding object equipped with electronic components such as semiconductor devices. The molding object is then clamped from above and below between the lower mold, whose cavity recess is filled with a sealing resin material, and the upper mold, to which the molding object is fixed, to perform compression molding, resulting in resin molding. During this process, the base of the lower mold rises, applying pressure to compress the sealing resin material. Because the cavity becomes shallower at this time, a slight gap is created between the release film and the inner surface of the cavity recess. This has been shown to cause deformation of the release film, leading to distortion and wrinkles. Therefore, the release film placed on the mold was required to have sufficient flexibility and extensibility to accommodate local deformation.

[0006] On the other hand, according to the present inventors, when an attempt is made to increase the flexibility or elongation of a release film, the thickness of the release film must be reduced, which is a constraint. It has been found that when the film is made thin, the stiffness of the film cannot be sufficiently ensured, and this tends to decrease workability.

[0007] Therefore, the inventors of the present invention conducted further intensive research from the viewpoint of achieving both a molded article with a good appearance using a release film and the workability of the release film, and discovered that it is effective to specify and combine the materials of the release layer that constitutes the release surface of the release film, the second base material layer that constitutes the opposite surface, and the first base material layer that is interposed between the two.

[0008] According to the present invention, A release film having a multilayer structure in which a release layer, a first base layer, and a second base layer are laminated in this order, The release layer constitutes a release surface of the release film, and the second base layer constitutes a surface of the release film opposite to the release surface, the release layer contains one or more resins selected from a silicone resin, a fluororesin, a melamine resin, an epoxy resin, a phenolic resin, and an acrylic resin; the first base layer is made of a stretched or unstretched film containing one or more resins selected from polyester resins, polyolefin resins, and polyamide resins; The second base layer is a release film made of a stretched or unstretched film containing one or more resins selected from polyester resin, polyolefin resin, and polyamide resin. [Effects of the Invention]

[0009] According to the present invention, there is provided a release film that improves the workability of the release film and allows a molded article with good appearance to be obtained. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a cross-sectional view schematically showing a cross section of a release film of the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In all drawings, similar components are given the same reference numerals, and explanations are omitted where appropriate. To avoid complexity, if there are multiple identical components in the same drawing, only one of them may be referenced, and not all of them. The drawings are for explanatory purposes only. The shape and dimensional ratios of each component in the drawings do not necessarily correspond to the actual product.

[0012] In this specification, unless otherwise specified, the expression "a to b" in the description of a numerical range means from a to b. For example, "1 to 5 mass %" means "1 mass % to 5 mass %."

[0013] <Release film> FIG. 1 is a cross-sectional view that schematically shows a cross section of the release film of the present embodiment. As shown in FIG. 1, the release film 10 of this embodiment has a multilayer structure in which a release layer 1, a first substrate layer 3, and a second substrate layer 2 are laminated in this order, and the release layer 1 forms a release surface 11 of the release film 10, and the second substrate layer 2 forms a surface 21 opposite to the release surface 11 of the release film 10. In this embodiment, a release film 10 having a three-layer structure in which a release layer 1, a first substrate layer 3, and a second substrate layer 2 are laminated in this order will be described. However, it is sufficient that the release layer 1 and the second substrate layer 2 each constitute the outer surface of the release film 10, and a layer other than the first substrate layer 3 may be further interposed between the release layer 1 and the second substrate layer 2.

[0014] The release film 10 of this embodiment preferably has a dimensional change rate of 4 to 40%, more preferably 5 to 35%, and even more preferably 7 to 30% at 180°C when heated from 30°C to 180°C at a rate of 2°C / min under a tensile load of 500 mN, as determined by thermomechanical analysis (TMA). By setting the dimensional change rate within the above range, good conformability to the mold can be obtained when the release film 10 is placed in the mold while maintaining workability, and the occurrence of wrinkles and distortions in the release film 10 can be suppressed, thereby suppressing the transfer of wrinkles and distortions of the release film 10 to the molded article. As a result, a molded article with a good appearance can be obtained. In particular, when the release film 10 is vacuum-sealed to the inner surface of the cavity recess, if the suction port of the mold has a relatively deep groove, the release film 10 will also be drawn into the deep groove. Therefore, the release film 10 is required to be able to stretch locally sufficiently, and the release film 10 of the present embodiment can achieve this.

[0015] Furthermore, when the release film 10 of this embodiment is measured by dynamic mechanical analysis (DMA) under conditions of a temperature rise rate of 5°C / min and a frequency of 1 Hz, the storage modulus at 180°C is preferably 10 to 500 MPa, and more preferably 70 to 400 MPa. The storage modulus of the release film 10 at 180° C. refers to the storage modulus when the release film 10 is placed in a mold and heated and compressed. By setting the storage modulus at 180° C. of the release film 10 within the above range, it is possible to improve mold followability during vacuum adhesion while maintaining good mold releasability and cushioning properties.

[0016] Furthermore, the release film 10 of this embodiment preferably has a value measured by a loop stiffness test of 2 mN / cm or more, more preferably 5 mN / cm or more, and even more preferably 10 mN / cm or more, which can improve the workability of the film. On the other hand, the upper limit of the value measured by the loop stiffness test is not particularly limited, but from the viewpoint of maintaining the properties as a release film, it may be, for example, 100 mN / cm or less, or 80 mN / cm or less.

[0017] The above-mentioned dimensional change rate, storage modulus, and loop stiffness of the release film 10 of this embodiment can be achieved by selecting and combining known methods, such as the types of raw materials and film formation methods for the release layer 1, the first substrate layer 3, and the second substrate layer 2, controlling the surface roughness of the release film 10, and the manufacturing method of the release film 10, to create a method that differs from conventional methods. For example, stretching a film as a film formation method can produce a film that is harder and more resilient than an unstretched film. Furthermore, to improve the handleability of the release film 10, the surface conditions of the release surface 11 formed by the release layer 1 and the surface 21 formed by the second substrate layer 2, which constitute the outer surface of the release film 10, can be controlled to achieve a predetermined surface roughness and tackiness while providing the first substrate layer 3 with resilience. As an example of a method for producing the release film 10 of this embodiment, a coating liquid of the first resin composition that constitutes the release layer 1 can be applied to a strip-shaped laminate of the second substrate layer 2 and the first substrate layer 3 using a roll-to-roll method. In this case, if at least one of the second substrate layer 2 and the first substrate layer 3 is an unstretched film, tension generated by the roll-to-roll method is more likely to be applied to the second substrate layer 2 and the first substrate layer 3. Therefore, by setting the roll conveying tension in the roll-to-roll method to 100 N or less, the stress applied to the second substrate layer 2 and the first substrate layer 3 can be reduced, and the desired release film 10 can be obtained.

[0018] The thickness of the release film 10 is preferably 5 μm or more and 150 μm or less, more preferably 10 μm or more and 100 μm or less, and even more preferably 15 μm or more and 80 μm or less.

[0019] Hereinafter, each layer included in the release film 10 of this embodiment will be described in detail.

[0020] [Release layer 1] In this embodiment, the release layer 1 is a resin layer that forms one side 11 of the release film 10 and constitutes the surface that comes into contact with the sealing resin (later molded body) when the release film 10 is placed in a mold.

[0021] The thickness of the release layer 1 is preferably 0.01 to 50 μm, more preferably 0.05 to 30 μm, even more preferably 0.08 to 25 μm, and particularly preferably 0.1 to 15 μm. By making the thickness of the release layer 1 equal to or greater than the above lower limit, it is possible to impart the necessary releasability to the release film 10. On the other hand, by making the thickness of the release layer 1 equal to or less than the above upper limit, it is possible to control the rigidity of the release film 10 and achieve a good balance between mold followability and releasability.

[0022] Furthermore, the surface roughness Ra of the surface 11 of the release film 10 on the release layer 1 side is preferably 0.3 to 2 μm, more preferably 0.4 to 1.5 μm, and even more preferably 0.5 to 1.2 μm, from the viewpoint of releasability and good appearance of the molded product. By setting the surface roughness Ra of surface 11 to be equal to or greater than the above lower limit, a good balance can be achieved between mold releasability and mold followability during molding. On the other hand, by setting the surface roughness Ra of surface 11 to be equal to or less than the above upper limit, a good balance can be achieved between mold releasability and a good appearance of the molded product. From the viewpoint of imparting gloss to the appearance of a molded article obtained using the release film 10, it is preferable that the surface roughness Ra of the surface 11 is less than 0.2 μm.

[0023] The surface roughness of the surface 11 on the release layer 1 side can be controlled by known methods, such as transferring an embossed pattern to the film using an embossed roll during the release film manufacturing process, or by incorporating particles into the material of the release layer. The surface roughness Ra of the release layer 1 is measured in accordance with JIS B0601:2013.

[0024] In this embodiment, the release layer 1 is made of a first resin composition containing a resin.

[0025] The release layer 1 contains one or more resins selected from silicone resin, fluororesin, melamine resin, epoxy resin, phenolic resin, and acrylic resin. Among them, from the viewpoint of obtaining a good appearance of the molded article while improving the workability of the release film 10, it is preferable to contain one or more resins selected from silicone resin, melamine resin, and acrylic resin, and it is more preferable to contain melamine resin or acrylic resin.

[0026] (silicone resin) The silicone resin is not particularly limited, and may be, for example, a compound containing two or more siloxane bonds (—Si—O—), such as various known or commercially available siloxane-based polymers.

[0027] The silicone resin preferably contains one or two selected from, for example, vinyl group-containing organopolysiloxane (A) and organohydrogenpolysiloxane (B), which provides rubber-like properties such as silicone elasticity and compressibility, making it easier to obtain sufficient elongation of the release film and shape recovery after elongation.

[0028] <<Vinyl group-containing organopolysiloxane (A)>> The vinyl group-containing organopolysiloxane (A) can contain a vinyl group-containing linear organopolysiloxane (A1) having a linear structure.

[0029] The vinyl group-containing linear organopolysiloxane (A1) has a linear structure and contains vinyl groups, which become crosslinking points during curing.

[0030] The vinyl group content of the vinyl group-containing linear organopolysiloxane (A1) is not particularly limited, but preferably has two or more vinyl groups in the molecule and is 15 mol% or less, which optimizes the amount of vinyl groups in the vinyl group-containing linear organopolysiloxane (A1) and ensures the formation of networks with the components described below.

[0031] In this specification, the vinyl group content refers to the mole percent of vinyl group-containing siloxane units when all units constituting the vinyl group-containing linear organopolysiloxane (A1) are taken as 100 mole percent, where it is considered that there is one vinyl group per vinyl group-containing siloxane unit.

[0032] The degree of polymerization of the vinyl group-containing linear organopolysiloxane (A1) is not particularly limited, but is preferably within a range of, for example, about 1,000 to 10,000, and more preferably about 2,000 to 5,000. The degree of polymerization can be determined, for example, as the polystyrene-equivalent number-average degree of polymerization (or number-average molecular weight) measured by GPC (gel permeation chromatography) using chloroform as a developing solvent.

[0033] Furthermore, the specific gravity of the vinyl group-containing linear organopolysiloxane (A1) is not particularly limited, but is preferably in the range of about 0.9 to 1.1.

[0034] By using a vinyl group-containing linear organopolysiloxane (A1) having a degree of polymerization and specific gravity within the above ranges, it is possible to improve the heat resistance, flame retardancy, chemical stability, etc. of the resulting silicone rubber.

[0035] The vinyl group-containing linear organopolysiloxane (A1) preferably has a structure represented by the following formula (1):

[0036] [ka]

[0037] In formula (1), R 1is a hydrocarbon group selected from substituted or unsubstituted alkyl groups, alkenyl groups, aryl groups, or combinations thereof having 1 to 10 carbon atoms. Examples of alkyl groups having 1 to 10 carbon atoms include methyl groups, ethyl groups, and propyl groups, with methyl groups being preferred. Examples of alkenyl groups having 1 to 10 carbon atoms include vinyl groups, allyl groups, and butenyl groups, with vinyl groups being preferred. Examples of aryl groups having 1 to 10 carbon atoms include phenyl groups.

[0038] Also, R 2 is a substituted or unsubstituted alkyl group, alkenyl group, aryl group, or a hydrocarbon group combining these groups, each having 1 to 10 carbon atoms. Examples of alkyl groups having 1 to 10 carbon atoms include methyl, ethyl, and propyl groups, with methyl being preferred. Examples of alkenyl groups having 1 to 10 carbon atoms include vinyl, allyl, and butenyl groups. Examples of aryl groups having 1 to 10 carbon atoms include phenyl groups.

[0039] Also, R 3 is a substituted or unsubstituted alkyl group or aryl group having 1 to 8 carbon atoms, or a hydrocarbon group consisting of a combination thereof. Examples of alkyl groups having 1 to 8 carbon atoms include methyl, ethyl, and propyl groups, with methyl being preferred. Examples of aryl groups having 1 to 8 carbon atoms include phenyl groups.

[0040] Furthermore, R in formula (1) 1 and R 2 Examples of the substituent of R include a methyl group and a vinyl group. 3 Examples of the substituent include a methyl group.

[0041] In addition, in formula (1), multiple R 1 are independent of each other and may be different or the same. 2 , and R 3 The same is true for .

[0042] Furthermore, m and n are the numbers of repeating units constituting the vinyl group-containing linear organopolysiloxane (A1) represented by formula (1), where m is an integer of 0 to 2000 and n is an integer of 1000 to 10000. m is preferably 0 to 1000, and n is preferably 2000 to 5000.

[0043] Specific examples of the vinyl group-containing linear organopolysiloxane (A1) represented by formula (1) include those represented by the following formula (1-1).

[0044] [ka]

[0045] In formula (1-1), R 1 and R 2 are each independently a methyl group or a vinyl group, and at least one of them is a vinyl group.

[0046] The vinyl group-containing linear organopolysiloxane (A1) may contain a first vinyl group-containing linear organopolysiloxane (A1-1) having two or more vinyl groups in the molecule and having a vinyl group content of 0.4 mol% or less. The vinyl group content of the first vinyl group-containing linear organopolysiloxane (A1-1) may be 0.1 mol% or less.

[0047] The vinyl group-containing linear organopolysiloxane (A1) may also contain a first vinyl group-containing linear organopolysiloxane (A1-1) and a second vinyl group-containing linear organopolysiloxane (A1-2) having a vinyl group content of 0.5 to 15 mol %.

[0048] By combining a first vinyl-containing linear organopolysiloxane (A1-1) with a second vinyl-containing linear organopolysiloxane (A1-2) having a high vinyl group content as the raw rubber used to make the silicone rubber, the vinyl groups can be unevenly distributed, allowing for more effective formation of a crosslink density distribution within the crosslinked network of the silicone rubber. As a result, the tear strength of the release film can be more effectively increased, and dimensional stability and transferability can be more easily controlled.

[0049] Specifically, the vinyl group-containing linear organopolysiloxane (A1) may be, for example, a vinyl group-containing linear organopolysiloxane represented by the above formula (1-1), 1 is a vinyl group and / or R 2 a first vinyl group-containing linear organopolysiloxane (A1-1) having two or more units in the molecule in which R is a vinyl group and containing 0.4 mol % or less of the unit; 1 is a vinyl group and / or R 2 It is preferable to use a second vinyl group-containing linear organopolysiloxane (A1-2) containing 0.5 to 15 mol % of units in which each of the units is a vinyl group.

[0050] The first vinyl group-containing linear organopolysiloxane (A1-1) preferably has a vinyl group content of 0.01 to 0.2 mol %, and the second vinyl group-containing linear organopolysiloxane (A1-2) preferably has a vinyl group content of 0.8 to 12 mol %.

[0051] Furthermore, when the first vinyl group-containing linear organopolysiloxane (A1-1) and the second vinyl group-containing linear organopolysiloxane (A1-2) are combined and blended, the ratio of (A1-1) to (A1-2) is not particularly limited, but for example, the weight ratio of (A1-1):(A1-2) is preferably 50:50 to 95:5, and more preferably 80:20 to 90:10.

[0052] The first and second vinyl group-containing linear organopolysiloxanes (A1-1) and (A1-2) may each be used alone or in combination of two or more.

[0053] The vinyl group-containing organopolysiloxane (A) may also contain a vinyl group-containing branched organopolysiloxane (A2) having a branched structure.

[0054] <<Organohydrogenpolysiloxane (B)>> The organohydrogenpolysiloxane (B) is classified into a linear organohydrogenpolysiloxane (B1) having a linear structure and a branched organohydrogenpolysiloxane (B2) having a branched structure, and may contain either one or both of these.

[0055] The linear organohydrogenpolysiloxane (B1) has a linear structure and a structure in which hydrogen is directly bonded to Si (≡Si-H), and is a polymer that undergoes a hydrosilylation reaction with the vinyl groups of the vinyl group-containing organopolysiloxane (A) and with vinyl groups of components contained in the raw materials of the release layer 1, thereby crosslinking these components.

[0056] The molecular weight of the linear organohydrogenpolysiloxane (B1) is not particularly limited, but for example, the weight average molecular weight is preferably 20,000 or less, and more preferably 1,000 or more and 10,000 or less.

[0057] The weight average molecular weight of the linear organohydrogenpolysiloxane (B1) can be measured, for example, by gel permeation chromatography (GPC) using chloroform as a developing solvent, in terms of polystyrene.

[0058] Furthermore, it is generally preferred that the linear organohydrogenpolysiloxane (B1) does not contain a vinyl group, which can reliably prevent the crosslinking reaction from proceeding within the molecule of the linear organohydrogenpolysiloxane (B1).

[0059] As the linear organohydrogenpolysiloxane (B1) described above, for example, one having a structure represented by the following formula (2) is preferably used.

[0060] [ka]

[0061] In formula (2), R 4 is a substituted or unsubstituted alkyl group, alkenyl group, aryl group, a hydrocarbon group combining these, or a hydride group having 1 to 10 carbon atoms. Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, and a propyl group, with a methyl group being preferred. Examples of the alkenyl group having 1 to 10 carbon atoms include a vinyl group, an allyl group, and a butenyl group. Examples of the aryl group having 1 to 10 carbon atoms include a phenyl group.

[0062] Also, R 5 is a substituted or unsubstituted alkyl group, alkenyl group, aryl group, a hydrocarbon group combining these, or a hydride group having 1 to 10 carbon atoms. Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, and a propyl group, with a methyl group being preferred. Examples of the alkenyl group having 1 to 10 carbon atoms include a vinyl group, an allyl group, and a butenyl group. Examples of the aryl group having 1 to 10 carbon atoms include a phenyl group.

[0063] In addition, in formula (2), multiple R 4 are independent of each other and may be different or the same. 5 The same applies to multiple R 4 and R5 At least two of these are hydride groups.

[0064] Also, R 6 is a substituted or unsubstituted alkyl group or aryl group having 1 to 8 carbon atoms, or a hydrocarbon group combining these. Examples of alkyl groups having 1 to 8 carbon atoms include methyl groups, ethyl groups, and propyl groups, with methyl groups being preferred. Examples of aryl groups having 1 to 8 carbon atoms include phenyl groups. 6 are independent of each other and may be different from each other or may be the same.

[0065] In addition, R in formula (2) 4 ,R 5 ,R 6 Examples of the substituent include a methyl group and a vinyl group, and a methyl group is preferred from the viewpoint of preventing intramolecular crosslinking reactions.

[0066] Furthermore, m and n are the numbers of repeating units constituting the linear organohydrogenpolysiloxane (B1) represented by formula (2), where m is an integer of 2 to 150 and n is an integer of 2 to 150. Preferably, m is an integer of 2 to 100 and n is an integer of 2 to 100.

[0067] The linear organohydrogenpolysiloxane (B1) may be used alone or in combination of two or more.

[0068] Because the branched organohydrogenpolysiloxane (B2) has a branched structure, it forms regions with high crosslink density, and is a component that significantly contributes to the formation of a sparsely crosslinked structure within the silicone rubber system. Like the linear organohydrogenpolysiloxane (B1), it has a structure in which hydrogen is directly bonded to silicon (≡Si-H), and undergoes a hydrosilylation reaction with the vinyl groups of the vinyl-group-containing organopolysiloxane (A) and with the vinyl groups of the components contained in the raw materials for the release layer 1, forming a polymer that crosslinks these components.

[0069] The specific gravity of the branched organohydrogenpolysiloxane (B2) is in the range of 0.9 to 0.95.

[0070] Furthermore, it is generally preferred that the branched organohydrogenpolysiloxane (B2) does not contain vinyl groups, which can reliably prevent crosslinking reactions from occurring within the molecules of the branched organohydrogenpolysiloxane (B2).

[0071] The branched organohydrogenpolysiloxane (B2) is preferably one represented by the following average composition formula (c):

[0072] Average composition formula (c) (H a (R 7 ) 3-a SiO 1 / 2 ) m (SiO 4 / 2 ) n (In formula (c), R 7 is a monovalent organic group, a is an integer ranging from 1 to 3, and m is H a (R 7 ) 3-a SiO 1 / 2 The number of units, n, is SiO 4 / 2 (the number of units)

[0073] In formula (c), R 7 is a monovalent organic group, preferably a substituted or unsubstituted alkyl group or aryl group having 1 to 10 carbon atoms, or a hydrocarbon group consisting of a combination thereof. Examples of alkyl groups having 1 to 10 carbon atoms include methyl, ethyl, and propyl groups, with methyl being preferred. Examples of aryl groups having 1 to 10 carbon atoms include phenyl groups.

[0074] In formula (c), a is the number of hydride groups (hydrogen atoms directly bonded to Si), and is an integer ranging from 1 to 3, preferably 1.

[0075] In addition, in formula (c), m is H a(R 7 ) 3-a SiO 1 / 2 The number of units, n, is SiO 4 / 2 The number of units.

[0076] The branched organohydrogenpolysiloxane (B2) has a branched structure. The linear organohydrogenpolysiloxane (B1) and the branched organohydrogenpolysiloxane (B2) differ in their structures, that is, whether they are linear or branched. The number of alkyl groups R bonded to Si (R / Si), where the number of Si is 1, is in the range of 1.8 to 2.1 for the linear organohydrogenpolysiloxane (B1) and 0.8 to 1.7 for the branched organohydrogenpolysiloxane (B2).

[0077] Because the branched organohydrogenpolysiloxane (B2) has a branched structure, it leaves a residue amount of 5% or more when heated, for example, in a nitrogen atmosphere to 1000°C at a heating rate of 10°C / min. In contrast, because the linear organohydrogenpolysiloxane (B1) is linear, it leaves almost no residue amount after heating under the above conditions.

[0078] Specific examples of the branched organohydrogenpolysiloxane (B2) include those having a structure represented by the following formula (3).

[0079] [ka]

[0080] In formula (3), R 7 R is a substituted or unsubstituted alkyl group or aryl group having 1 to 8 carbon atoms, or a hydrocarbon group combining these, or a hydrogen atom. Examples of alkyl groups having 1 to 8 carbon atoms include methyl, ethyl, and propyl groups, with methyl being preferred. Examples of aryl groups having 1 to 8 carbon atoms include phenyl groups. 7 Examples of the substituent include a methyl group.

[0081] In addition, in formula (3), multiple R 7 are independent of each other and may be different from each other or may be the same.

[0082] In addition, in formula (3), "-O-Si≡" indicates that Si has a branched structure that spreads three-dimensionally.

[0083] The branched organohydrogenpolysiloxane (B2) may be used alone or in combination of two or more.

[0084] In the linear organohydrogenpolysiloxane (B1) and the branched organohydrogenpolysiloxane (B2), the amount of hydrogen atoms (hydride groups) directly bonded to Si is not particularly limited. However, in the release layer 1, the total amount of hydride groups in the linear organohydrogenpolysiloxane (B1) and the branched organohydrogenpolysiloxane (B2) is preferably 0.5 to 5 moles, more preferably 1 to 3.5 moles, per mole of vinyl groups in the vinyl group-containing linear organopolysiloxane (A1). This ensures the reliable formation of a crosslinked network between the linear organohydrogenpolysiloxane (B1) and the branched organohydrogenpolysiloxane (B2) and the vinyl group-containing linear organopolysiloxane (A1).

[0085] (Fluorine resin) Specific examples of the fluorine-based resin include polymers of monomers such as tetrafluoroethylene, hexafluoropropylene, chlorotrifluoroethylene, vinylidene fluoride, vinyl fluoride, and perfluoroalkyl vinyl ether, and copolymers of two or more monomers. These may be used alone or in combination of two or more.

[0086] (melamine resin) The melamine resin can be obtained, for example, by polycondensing a melamine compound with formaldehyde under neutral or weak alkaline conditions. Specific examples include alkylated melamine resins such as methylated melamine resins and butylated melamine resins, methylolated melamine resins, and alkyl-etherified melamine resins.

[0087] Among these, a methylated melamine resin containing a structural unit derived from methylated melamine is preferred. The methylated melamine resin has at least one methoxymethyl group (-CH2OCH3) and an average degree of polymerization of 1.1 to 10.

[0088] (epoxy resin) The epoxy resin may be any monomer, oligomer, or polymer having two or more epoxy groups per molecule, regardless of its molecular weight or molecular structure. Specific examples of such epoxy resins include bisphenol-type epoxy resins such as bisphenol A-type epoxy resin, bisphenol F-type epoxy resin, bisphenol E-type epoxy resin, bisphenol S-type epoxy resin, hydrogenated bisphenol A-type epoxy resin, bisphenol M-type epoxy resin (4,4'-(1,3-phenylenediisopridiene)bisphenol-type epoxy resin), bisphenol P-type epoxy resin (4,4'-(1,4-phenylenediisopridiene)bisphenol-type epoxy resin), and bisphenol Z-type epoxy resin (4,4'-cyclohexydienebisphenol-type epoxy resin); novolac-type epoxy resins such as phenol novolac-type epoxy resin, brominated phenol novolac-type epoxy resin, cresol novolac-type epoxy resin, tetraphenol-group ethane novolac-type epoxy resin, and novolac-type epoxy resin having a condensed ring aromatic hydrocarbon structure; biphenyl-type epoxy resin; and xylitol. aralkyl-type epoxy resins such as aralkyl-type epoxy resins, such as naphthylene ether-type epoxy resins, naphthol-type epoxy resins, naphthalene-type epoxy resins, naphthalenediol-type epoxy resins, difunctional to tetrafunctional epoxy-type naphthalene resins, binaphthyl-type epoxy resins, and naphthalenearalkyl-type epoxy resins; epoxy resins having a naphthalene skeleton, such as anthracene-type epoxy resins; phenoxy-type epoxy resins; dicyclopentadiene-type epoxy resins; norbornene-type epoxy resins; adamantane-type epoxy resins; fluorene-type epoxy resins, phosphorus-containing epoxy resins, alicyclic epoxy resins, aliphatic linear epoxy resins, bisphenol A novolac-type epoxy resins, bixylenol-type epoxy resins, triphenolmethane-type epoxy resins, trihydroxyphenylmethane-type epoxy resins, tetraphenylolethane-type epoxy resins, and heterocyclic epoxy resins such as triglycidyl isocyanurate;The copolymer may contain one or more selected from the group consisting of glycidyl amines such as N,N,N',N'-tetraglycidyl meta-xylenediamine, N,N,N',N'-tetraglycidyl bisaminomethylcyclohexane, and N,N-diglycidylaniline, copolymers of glycidyl (meth)acrylate with compounds having ethylenically unsaturated double bonds, epoxy resins having a butadiene structure, diglycidyl ethers of bisphenols, diglycidyl ethers of naphthalenediol, and glycidyl ethers of phenols;

[0089] (phenolic resin) The phenolic resin may include one or more selected from the group consisting of novolac-type phenolic resins such as phenol novolac resin, cresol novolac resin, tert-butylphenol novolac resin, and nonylphenol novolac resin; phenol aralkyl resins such as phenylene skeleton-containing phenol aralkyl resin and biphenylene skeleton-containing phenol aralkyl resin; and phenolic resins having a condensed polycyclic structure such as a naphthalene skeleton or an anthracene skeleton.

[0090] (acrylic resin) Specific examples of acrylic resins include resins composed of monomers such as acrylic acid, methacrylic acid, acrylic acid esters such as methyl acrylate, ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate; methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, and butyl methacrylate; acrylonitrile, methacrylonitrile, and acrylamide. The constituent monomers of the acrylic resin include one or more of these exemplified monomers. The constituent monomers of the acrylic resin may also include monomers other than these exemplified monomers. The acrylic resin may also be a derivative of these monomers.

[0091] In addition to the resins described above, the first resin composition may contain other components as long as they do not impair the properties of the release film 10. These other components are not limited to, but may include, for example, particles, coupling agents, acid catalysts, solvents, antistatic agents, leveling agents, dispersants, pigments, dyes, antioxidants, flame retardants, and thermal conductivity improvers, as well as polybutadiene, polyisoprene, polychloroprene, polypentadiene, polybutene, polyisobutylene, polystyrene, isoprene-butadiene copolymers, styrene-isoprene copolymers, polyolefins and their derivatives, silicone resins, isocyanate group-containing compounds, epoxy group-containing compounds, amines, carboxylic acid anhydrides, and long-chain alkyl group-containing alcohols. Representative components are described below.

[0092] (particle) The release layer 1 may contain particles. This makes it possible to easily control the surface roughness of the surface 11 of the release film 10, regardless of the method for forming the release layer 1. That is, when the release layer 1 is a stretched film, it is difficult to emboss the surface 11 of the release film 10 facing the release layer 1. However, by including particles in the release layer 1, it is possible to control the surface roughness whether the release layer 1 is a stretched film or an unstretched film. Furthermore, compared to when the surface 11 of the release film 10 facing the release layer 1 is subjected to a roughening treatment, the surface roughness can be easily increased by adjusting the particle size and content of the particles.

[0093] Examples of the particles contained in the release layer 1 include particles containing one or more organic particles and / or inorganic particles selected from the group consisting of melamine resin, polystyrene resin, acrylic resin, polyimide resin, polyester resin, silicone resin, polypropylene resin, polyethylene resin, and fluororesin. The release layer 1 of this embodiment may contain one or more of these particles.

[0094] Examples of the inorganic particles include silicates such as talc, calcined clay, uncalcined clay, mica, and glass; oxides such as titanium oxide, alumina, boehmite, and silica; carbonates such as calcium carbonate, magnesium carbonate, and hydrotalcite; hydroxides such as aluminum hydroxide, magnesium hydroxide, and calcium hydroxide; sulfates or sulfites such as barium sulfate, calcium sulfate, and calcium sulfite; borates such as zinc borate, barium metaborate, aluminum borate, calcium borate, and sodium borate; nitrides such as aluminum nitride, boron nitride, silicon nitride, and carbon nitride; and titanates such as strontium titanate and barium titanate. These may be used alone or in combination of two or more. The inorganic particles are preferably surface-treated to enhance adhesion to the release layer 1. The surface treatment is appropriately selected depending on the organic material constituting the release layer 1. For example, when the release layer 1 contains a melamine resin, a coupling agent having a functional group such as amine, epoxy, or isocyanate may be used. The coupling agent will be described later.

[0095] The content of particles contained in the release layer 1 is preferably 10 to 50 mass % relative to the total mass of the release layer 1, more preferably 15 to 45 mass %, and even more preferably 20 to 40 mass %. By making the particle content equal to or greater than the lower limit, the surface roughness of face 11 can be increased, and good releasability and ease of handling can be obtained. On the other hand, by setting the particle content to the above upper limit or less, good film-forming properties can be maintained. When the release film 10 is used to impart gloss to the molded article obtained, the content of the particles may be 0% by mass.

[0096] (Silane coupling agent) The silane coupling agent may have a hydrolyzable group, which is hydrolyzed by water to form a hydroxyl group, which undergoes a dehydration condensation reaction with the hydroxyl groups on the surface of the inorganic particles, thereby modifying the surface of the inorganic particles.

[0097] The silane coupling agent may contain a silane coupling agent having a reactive group such as a vinyl group, an epoxy group, an isocyanate group, or an amino group, which allows the inorganic particles whose surfaces have been modified with the silane coupling agent to react with the resin in the release layer 1, thereby preventing the inorganic particles from falling off the release layer 1.

[0098] (acid catalyst) The acid catalyst is not particularly limited, but examples thereof include inorganic acids and organic acids. Examples of inorganic acids include hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, etc. Examples of organic acids include organic carboxylic acids, organic sulfonic acids, and organic phosphoric acids, etc. Examples of organic carboxylic acids include oxalic acid, acetic acid, formic acid, etc. Examples of organic sulfonic acids include methanesulfonic acid, trifluoromethanesulfonic acid, isoprene sulfonic acid, camphorsulfonic acid, hexanesulfonic acid, octane sulfonic acid, nonanesulfonic acid, decane sulfonic acid, hexadecanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, cumenesulfonic acid, dodecylbenzenesulfonic acid, naphthalenesulfonic acid, and nonylnaphthalenesulfonic acid. Examples of organic phosphates include methyl acid phosphate, ethyl acid phosphate, propyl acid phosphate, isopropyl acid phosphate, butyl acid phosphate, butoxyethyl acid phosphate, octyl acid phosphate, 2-ethylhexyl acid phosphate, decyl acid phosphate, lauryl acid phosphate, stearyl acid phosphate, oleyl acid phosphate, behenyl acid phosphate, phenyl acid phosphate, nonylphenyl acid phosphate, cyclohexyl acid phosphate, phenoxyethanol, methyl acid phosphate, alkoxy polyethylene glycol acid phosphate, bisphenol A acid phosphate, dimethyl acid phosphate, diethyl acid phosphate, dipropyl acid phosphate, diisopropyl acid phosphate, dibutyl acid phosphate, dioctyl acid phosphate, di-2-ethylhexyl acid phosphate, dioctyl acid phosphate, dilauryl acid phosphate, distearyl acid phosphate, diphenyl acid phosphate, and bisnonylphenyl acid phosphate. Examples of the thermal acid generator include sulfonium salts, benzothiazolium salts, ammonium salts, and phosphonium salts. Such acid catalysts can be used singly or in combination of two or more.

[0099] (solvent) The first resin composition may contain, for example, a solvent depending on the method for producing the release layer 1. When the first resin composition contains a solvent, the release layer 1 can be produced by dissolving the first resin composition in the solvent and applying the solution. The solvent is not limited, and specific examples thereof include aliphatic hydrocarbons such as water, pentane, hexane, cyclohexane, heptane, methylcyclohexane, ethylcyclohexane, octane, decane, dodecane, and tetradecane; aromatic hydrocarbons such as benzene, toluene, ethylbenzene, xylene, trifluoromethylbenzene, and benzotrifluoride; diethyl ether, diisopropyl ether, dibutyl ether, cyclopentyl methyl ether, cyclopentyl ethyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and diethylene Examples of suitable solvents include ethers such as glycol dimethyl ether, 1,4-dioxane, 1,3-dioxane, and tetrahydrofuran; haloalkanes such as dichloromethane, chloroform, 1,1-dichloroethane, 1,2-dichloroethane, 1,1,1-trichloroethane, and 1,1,2-trichloroethane; carboxylic acid amides such as N,N-dimethylformamide and N,N-dimethylacetamide; sulfoxides such as dimethyl sulfoxide and diethyl sulfoxide; and alcohols such as ethanol, isopropyl alcohol, and butanol. These may be used alone or in combination of two or more.

[0100] [Second base layer 2] In this embodiment, the second base layer 2 is a resin layer that forms one surface 21 of the release film 10 and that constitutes the surface that comes into contact with the mold when the release film 10 is placed in the mold.

[0101] The thickness of the second base layer 2 is preferably 10 to 100 μm, more preferably 15 to 80 μm, and even more preferably 20 to 50 μm. By setting the thickness of the second base layer 2 to the above lower limit or more, it is possible to increase the rigidity and maintain good handleability while maintaining the conformability of the release film 10. On the other hand, by setting the thickness of the second base layer 2 to the above upper limit or less, it is possible to improve the flexibility of the release film 10 and make it easier to obtain mold conformability.

[0102] In this embodiment, the second base layer 2 is a stretched or unstretched film made of a second resin composition containing a resin. Whether it is stretched or unstretched can be determined appropriately depending on the combination of the release layer 1 and the first base layer 3, but it is preferable to use a stretched film when improving the rigidity of the film, and an unstretched film when improving formability. The stretching can be carried out by using known methods such as sequential biaxial stretching, simultaneous biaxial stretching, and tubular stretching.

[0103] In this embodiment, the second base layer 2 contains one or more resins selected from polyester resins, polyolefin resins, and polyamide resins, of which polyester resins and polyolefin resins are preferred.

[0104] (polyester resin) Specific examples of the polyester resin include polyethylene terephthalate resin (PET), polybutylene terephthalate resin (PBT), polytrimethylene terephthalate resin (PTT), polyhexamethylene terephthalate resin (PHT), and polyethylene naphthalate resin (PEN), which may be used alone or in combination of two or more.

[0105] (Polyolefin resin) The polyolefin resin is a resin having structural units derived from α-olefins such as ethylene, propylene, and butene, and known polyolefin resins can be used. Specific examples of polyolefin resins include polyethylene (PE) such as low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), and linear low-density polyethylene (mLLLPE); polypropylene (PP); polyvinyl alcohol (PVA); ethylene-vinyl acetate copolymer (EVA); ethylene-methyl acrylate copolymer (EMA); ethylene-acrylic acid copolymer (EAA); ethylene-methyl methacrylate copolymer (EMMA); ethylene-ethyl acrylate copolymer (EEA); ethylene-methacrylic acid copolymer (EMAA); ionomer resins; ethylene-vinyl alcohol copolymer (EVOH); and cyclic olefin resins (COP). These may be used alone or in combination of two or more.

[0106] (Polyamide resin) Examples of the polyamide resin include aliphatic polyamides and aromatic polyamides. Specific examples of aliphatic polyamides include polyamide 6, polyamide 6,6, polyamide 6-6,6 copolymer, polyamide 11, and polyamide 12. Specific examples of aromatic polyamides include polyamide 61, polyamide 66 / 6T, polyamide 6T / 6, and polyamide 12 / 6T.

[0107] The second resin composition may contain other components in addition to the above-mentioned components, as long as they do not impair the properties of the release film 10. The other components are not limited, and the same components as those listed for the first resin composition above can be used.

[0108] [First base layer 3] In this embodiment, the first base material layer 3 is a resin layer located between the release layer 1 and the second base material layer 2 in the release film 10 having a multilayer structure. In this embodiment, the first base layer 3 imparts appropriate stiffness to the release film 10, and can improve the handleability of the release film 10 while maintaining its conformability.

[0109] The thickness of the first substrate layer 3 is preferably adjusted appropriately depending on the thickness of the second substrate layer 2, and the total thickness of the first substrate layer 3 and the second substrate layer 2 is preferably 25 to 70 μm, and more preferably 30 to 50 μm. By making the total thickness of the first base material layer 3 and the second base material layer 2 equal to or greater than the above lower limit, it is possible to increase the rigidity and maintain good handleability while maintaining the conformability of the release film 10. On the other hand, by making the total thickness of the first base material layer 3 and the second base material layer 2 equal to or less than the above upper limit, the flexibility of the release film 10 is improved and it becomes easier to obtain conformability.

[0110] In this embodiment, the first base layer 3 is a stretched or unstretched film made of a third resin composition containing a resin. Whether it is stretched or unstretched can be determined appropriately depending on the combination of the release layer 1 and the second base layer 2, but it is preferable to use a stretched film when improving the rigidity of the film, and to use a stretched film when improving formability. The stretching can be carried out by using known methods such as sequential biaxial stretching, simultaneous biaxial stretching, and tubular stretching.

[0111] As the third resin composition, the same components as those described for the second resin composition constituting the second base layer 2 above can be used. Furthermore, the third resin composition and the second resin composition may be the same or different.

[0112] In this embodiment, the first base layer 3 contains one or more resins selected from polyester resins, polyolefin resins, and polyamide resins. As these polyester resins, polyolefin resins, and polyamide resins, the same resins as those described above for the second base layer 2 can be used. Among these, polyamide resin is preferred for the first base layer 3, and polyester resin is more preferred.

[0113] <Release film manufacturing method> Next, a method for producing the release film 10 of this embodiment will be described. The release film 10, or the release layer 1, the first base layer 3 and the second base layer 2 can be manufactured by known methods, such as co-extrusion, extrusion lamination, dry lamination, inflation, inflation extrusion, T-die extrusion, etc. Specifically, for example, (i) a film-like second substrate layer 2 and a first substrate layer 3 may be formed, and the second substrate layer 2 and the first substrate layer 3 may be laminated together by lamination or the like, and then a coating liquid (varnish or paste) of the first resin composition constituting the release layer 1 may be applied to the first substrate layer 3 and cured to form and laminate the release layer 1; or (ii) a film-like release layer 1, a second substrate layer 2, and a first substrate layer 3 may be formed separately, and then the first substrate layer 3 may be laminated so as to be sandwiched between the release layer 1 and the second substrate layer 2, and then bonded together by lamination or via an adhesive layer or the like to form the release film 10. By using the manufacturing method (i) above, the thickness of the release layer 1 can be reduced more simply and stably. By using the manufacturing method (ii) above, the thickness of the release layer 1 can be increased more simply and stably.

[0114] When the release layer 1, the second substrate layer 2, and the first substrate layer 3 are formed separately, films can be obtained by using known methods such as extrusion molding, calendar molding, press molding, coating, etc. Furthermore, each of the obtained films can be subjected to a stretching treatment, if necessary.

[0115] Furthermore, when using the above-mentioned coating method, for example, the first resin composition constituting the release layer 1 is uniformly mixed using any kneading device to prepare a coating liquid (varnish or paste), which is then coated onto the first substrate layer 3 to obtain a laminated structure of the first substrate layer 3 and the release layer 1.

[0116] The temperature during kneading is set appropriately depending on the type of resin, but for example, the roll temperature is preferably set to about 10 to 70°C, and more preferably about 25 to 30°C. The kneading time is preferably, for example, about 5 minutes to 1 hour, and more preferably about 10 to 40 minutes. The kneading device is not particularly limited, but examples that can be used include a kneader, a two-roll mill, a Banbury mixer (continuous kneader), and a pressure kneader. Next, the obtained coating liquid is applied to a surface to be coated to form a coating film. The coating method is not particularly limited, and various known means can be used. Examples include a roll coater, reverse roll coater, gravure coater, knife coater, bar coater, etc. When forming a laminated structure by a roll-to-roll method while winding or unwinding any one of the release layer 1, the second substrate layer 2, and the first substrate layer 3 onto or from a roll, it is preferable to reduce the tension caused by winding or unwinding as much as possible. In addition, the coating amount is preferably such that the weight after curing is 0.01 to 10 g / m 2 , more preferably 0.05 to 5 g / m 2 is. Each coating film can then be cured to form the desired film, for example, at 90 to 170° C. for 30 seconds to 5 minutes.

[0117] <Uses and methods of use of release film> The release film 10 of this embodiment is used in applications where it is disposed between a mold into which encapsulating resin is supplied and a semiconductor device to be encapsulated during the resin encapsulation process of a semiconductor device. That is, it may be a so-called mold-molding release film, or it may be used for other purposes. Other applications include, for example, its use between a cover film and a mold when a coverlay film (hereinafter also referred to as a "CL film") is bonded to a flexible film with exposed circuits (hereinafter also referred to as a "circuit-exposed film") via an adhesive by hot pressing to produce a flexible printed circuit board (hereinafter also referred to as an "FPC"). It can also be used, for example, as a release film for curing a prepreg of a thermosetting resin such as CFRP, a release film for molding a thermosetting resin, or a decorative transfer release film for printing on a three-dimensional product.

[0118] An example of a method for manufacturing a resin-sealed semiconductor device using the release film 10 will now be described.

[0119] The method for manufacturing a resin-encapsulated semiconductor device includes the following steps. (Step 1) Preparation of semiconductor device (Step 2) Release film installation process (Process 3) Sealing resin supply process (Step 4) Curing step (Step 5) Demolding process of the molded body Each step will be described in detail below.

[0120] (Step 1) Preparation of semiconductor device The semiconductor device is formed by electrically connecting electrode pads on circuit wiring provided on a support and electrodes provided on a semiconductor element. Examples of semiconductor elements include optical elements such as light-emitting elements and light-receiving elements. Examples of light-emitting elements include LED chips (light-emitting diodes), and examples of light-receiving elements include image sensors. The support is a substrate formed in any shape such as a circle or a polygon, etc. Examples of the support include a ceramic substrate, a silicone substrate, a metal substrate, a rigid substrate such as an epoxy resin or BT resin, or a flexible substrate such as a polyimide resin or polyethylene substrate.

[0121] (Step 2) Release film installation process The release film 10 is placed in a lower mold having a cavity recess for supplying the sealing resin, with the release surface 3 of the release film 10 facing the front side, i.e., in contact with the sealing resin to be supplied later. The release film 10 is disposed within the cavity recess of the lower mold and along the surface of the flat portion surrounding the cavity recess. At this time, a suction port is provided on the flat portion surrounding the cavity recess to allow the release film 10 to conform to the shape of the cavity recess of the lower mold. A suction device or the like is used to suck and discharge air, moisture, gas, and the like from the space between the release film 10 and the mold, thereby vacuum adsorbing the film. Furthermore, to firmly fix the release film 10 to the mold, the release film 10 may be clamped by a chuck mechanism disposed at a position corresponding to the periphery of the encapsulating resin injection area, the periphery of the entire release film 10, or the periphery of the entire mold. Examples of the mold include known metal molds and resin molds.

[0122] (Process 3) Sealing resin supply process Next, a sealing resin is supplied to the recessed portion of the mold where the release film 10 is placed. A known method can be used as the supply method. The sealing resin can be any known resin, such as silicone resin, epoxy resin, acrylic resin, fluorine resin, polyimide resin, silicone modified epoxy resin, or a mixture of these resins, or precursors thereof. In this embodiment, when the release film 10 is applied to a compression molding method, the sealing resin is preferably processed into the shape of a tablet, granule, sealed particle, or sheet. In the mold, the sealing resin is heated to a predetermined temperature and is in a fluid state.

[0123] (Step 4) Curing step Next, the semiconductor device to be molded is attached to an upper mold provided with protruding fixtures for holding the outer edge of the molded object to prevent it from falling, and the surface of the semiconductor device with the semiconductor element is placed facing the lower mold, and the mold is pressed against the mold with the encapsulating resin supplied into the recess. At this time, the fixtures of the upper mold fit into the grooves of the lower mold, and the semiconductor element is covered with the encapsulating resin. The encapsulating resin is then heated and pressurized to harden and obtain a molded product. When the sealing resin is a precursor of a curable resin, it may be cured by heating and irradiation with active energy rays, examples of which include radiation, ultraviolet rays, visible light, and electron beams.

[0124] (Step 5) Demolding process of the molded body The molded body is then removed from the mold. In the mold-releasing process for the molded body, air, moisture, gas, etc. are supplied between the release film 10 and the mold, so that the release film 10 is peeled off from the mold and the molded body is released. At the same time as or after this, the release film 10 is released from the molded body. When there is one semiconductor element provided on the support, this molded body becomes a resin-sealed semiconductor device. This makes it possible to obtain a semiconductor device with a good appearance.

[0125] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various other configurations may be adopted. Furthermore, the present invention is not limited to the above-described embodiments, and modifications and improvements within the scope of achieving the object of the present invention are included in the present invention. Below, examples of reference forms are added. 1. A release film having a multilayer structure in which a release layer, a first base layer, and a second base layer are laminated in this order, The release layer constitutes a release surface of the release film, and the second base layer constitutes a surface of the release film opposite to the release surface, the release layer contains one or more resins selected from a silicone resin, a fluororesin, a melamine resin, an epoxy resin, a phenolic resin, and an acrylic resin; the first base layer is made of a stretched or unstretched film containing one or more resins selected from polyester resins, polyolefin resins, and polyamide resins; The second base layer is a release film made of a stretched or unstretched film containing one or more resins selected from polyester resin, polyolefin resin, and polyamide resin. 2. 1. The release film according to claim 1, A release film having a loop stiffness of 2 mN / cm or more as measured by a loop stiffness test. 3. 1. The release film according to 1. or 2., The release film is characterized by a dimensional change rate of 4 to 40% at 180°C when the temperature is raised from 30°C to 180°C at a rate of 2°C / min under a tensile load of 500mN by thermomechanical analysis (TMA). 4. The release film according to any one of 1. to 3., When the release film is subjected to dynamic mechanical analysis (DMA) at a temperature rise rate of 5°C / min and a frequency of 1 Hz, the storage modulus at 180°C is 10 to 500 MPa. 5. The release film according to any one of 1. to 4., The release film has a surface roughness Ra of 0.3 to 2 μm on the surface of the release layer side. 6. The release film according to any one of 1. to 5., A release film, wherein the surface of the release film on the release layer side has a surface roughness Ra of less than 0.2 μm. 7. The release film according to any one of 1. to 6., A release film, wherein the total thickness of the first base material layer and the second base material layer is 25 to 70 μm. 8. The release film according to any one of 1. to 7., wherein the release film is used to be disposed between a mold and a semiconductor device in a resin-sealed semiconductor device molding process for resin-sealing the semiconductor device. [Example]

[0126] The present invention will be described in detail below with reference to examples, but the present invention is not limited to the descriptions of these examples.

[0127] (1) Preparation of First Resin Composition A first resin composition was prepared using the raw materials shown below. (Vinyl group-containing organopolysiloxane (A)) Low vinyl group-containing linear organopolysiloxane (A1-1): A vinyl group-containing dimethylpolysiloxane (having the structure represented by the above formula (1-1) and R 1 (Structure in which only the terminal is a vinyl group) High vinyl group-containing linear organopolysiloxane (A1-2): Vinyl group-containing dimethylpolysiloxane (structure represented by the above formula (1-1) and R1 and R 2 is a vinyl group)

[0128] (Organohydrogenpolysiloxane (B)) Momentive: TC-25D

[0129] (Inorganic filler) Inorganic filler (C): Silica fine particles (particle size 7 nm, specific surface area 300 m 2 / g), Nippon Aerosil Co., Ltd., "AEROSIL300"

[0130] (Silane coupling agent) Silane coupling agent (D-1): Hexamethyldisilazane (HMDZ), manufactured by Gelest, "HEXAMETHYLDISILAZANE (SIH6110.1)" Silane coupling agent (D-2): Divinyltetramethyldisilazane, manufactured by Gelest, "1,3-DIVINYLTETRAMETHYLDISILAZANE (SID4612.0)"

[0131] (Platinum or platinum compounds (E)) Momentive: TC-25A

[0132] (Synthesis of vinyl group-containing organopolysiloxane (A)) [Synthesis Scheme 1: Synthesis of Low-Vinyl-Containing Linear Organopolysiloxane (A1-1)] A low-vinyl-group-containing linear organopolysiloxane (A1-1) was synthesized according to the following formula (5). Specifically, 74.7 g (252 mmol) of octamethylcyclotetrasiloxane and 0.1 g of potassium siliconate were placed in a 300 mL separable flask equipped with a condenser and stirring blade and purged with Ar gas, and the mixture was heated to 120° C. and stirred for 30 minutes. An increase in viscosity was confirmed during this time. The temperature was then raised to 155°C and stirring was continued for 3 hours, after which 0.1 g (0.6 mmol) of 1,3-divinyltetramethyldisiloxane was added and the mixture was further stirred at 155°C for 4 hours. After another 4 hours, the mixture was diluted with 250 mL of toluene and washed three times with water. The washed organic layer was reprecipitated and purified by washing with 1.5 L of methanol several times, and the oligomer and polymer were separated. The resulting polymer was dried overnight under reduced pressure at 60°C to obtain a low-vinyl-group-containing linear organopolysiloxane (A1-1) (Mn = 2.2 × 10 5 , Mw=4.8×10 5 The vinyl group content calculated by H-NMR spectroscopy was 0.04 mol %.

[0133] [ka]

[0134] [Synthesis Scheme 2: Synthesis of High-Vinyl-Group-Containing Linear Organopolysiloxane (A1-2)] A highly vinyl-containing linear organopolysiloxane (A1-2) was synthesized as shown in formula (6) below by the same procedure as in the synthesis of (A1-1), except that 0.86 g (2.5 mmol) of 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane was used in addition to 74.7 g (252 mmol) of octamethylcyclotetrasiloxane. (Mn=2.3×10 5 , Mw=5.0×10 5 The vinyl group content calculated by H-NMR spectroscopy was 0.92 mol %. [ka]

[0135] Next, a mixture of 90% vinyl group-containing organopolysiloxane (A), a silane coupling agent, and water (F) was pre-kneaded in the proportions shown in Table 1 below, and then an inorganic filler was added to the mixture and further kneaded to obtain a kneaded product (silicone rubber compound). Here, the kneading after adding the inorganic filler was carried out through two steps: a first step in which kneading was carried out for 1 hour under a nitrogen atmosphere at 60 to 90°C for the coupling reaction, and a second step in which kneading was carried out for 2 hours under a reduced pressure atmosphere at 160 to 180°C for the removal of the by-product (ammonia).The mixture was then cooled, and the remaining 10% of the vinyl group-containing organopolysiloxane (A) was added in two portions, followed by kneading for 20 minutes. Next, organohydrogenpolysiloxane (B) (TC-25D) and platinum or platinum compound (E) (TC-25A) were added to 100 parts by weight of the obtained kneaded product (silicone rubber compound) in the proportions shown in Table 1 below, and the mixture was kneaded with a roll to obtain each first resin composition.

[0136] [Table 1]

[0137] (2) Creating a release film Each release film of the examples and comparative examples was produced as follows.

[0138] Example 1 As shown in Table 2, a 15 μm thick biaxially oriented polybutylene terephthalate (OPBT: manufactured by Toyobo Co., Ltd., Toyobo Ester (registered trademark) film, DE048) was used as the first substrate layer, and a 25 μm thick polybutylene terephthalate film (CPBT: manufactured by Okura Kogyo Co., Ltd., ESRM) was used as the second substrate layer. The first substrate layer and the second substrate were laminated using a laminating adhesive (TM593 (base), CAT-10L (curing agent), manufactured by Toyo Morton (solid content 25% by mass, solvent: ethyl acetate)). Furthermore, a melamine-based release agent (melamine: manufactured by Arakawa Chemical Industries, Ltd., Aracoat, RL3021 (base) / RA2000 (curing agent)) (solid content 10% by mass, solvent: IPA) prepared on the first substrate layer was applied using a bar coater and cured at 120 ° C. for 1 minute to obtain a release film having a release layer on the first substrate layer. The thickness of the release layer of the obtained release film was 40 μm, and the surface roughness Ra of the release surface of the release layer was 0.12 μm.

[0139] <Example 2> As shown in Table 2, a release film was prepared in the same manner as in Example 1, except that the melamine-based release agent was changed to an acrylic-based release agent (acrylic: manufactured by Tokushiki Corporation, SQ100 (main agent) / UAX-615 (curing agent)) (solid content 10% by mass, solvent: ethyl acetate) for the release layer. The drying conditions were 80°C for 3 minutes and 40°C for 3 days.

[0140] Example 3 As shown in Table 2, a release layer was formed by changing the melamine-based release agent to a paste (solid content 25% by mass, decane solvent) made from the first resin composition prepared in (2) above, to obtain a laminated film. A release film was produced in the same manner as in Example 1, except that the surface of the release layer was textured by sandwiching the obtained laminated film between a roll and a matte film when it was wound up on a roll. The release layer was cured at 180°C for 120 minutes.

[0141] Example 4 As shown in Table 2, release films were prepared in the same manner as in Example 3, except that the surface roughness of the matte film was changed.

[0142] <Example 5> As shown in Table 2, a release film was prepared in the same manner as in Example 1, except that the second base layer was changed to a polybutylene terephthalate film (CPBT: manufactured by Okura Kogyo Co., Ltd., ESRM) having a thickness of 35 μm.

[0143] Example 6 As shown in Table 2, a release film was prepared in the same manner as in Example 1, except that the first substrate layer was a 25 μm thick polybutylene terephthalate film (CPBT: manufactured by Okura Kogyo Co., Ltd., ESRM) and the second substrate layer was a 15 μm thick biaxially oriented polybutylene terephthalate (OPBT: manufactured by Toyobo Co., Ltd., Toyobo Ester (registered trademark) film, DE048).

[0144] Example 7 As shown in Table 2, a release film was produced in the same manner as in Example 1, except that the first substrate layer was made of biaxially oriented polyethylene terephthalate (OPET1: manufactured by Toyobo Film Solutions Co., Ltd., Teflex (registered trademark) film FW2) 13 μm thick and the second substrate layer was made of polybutylene terephthalate film (CPBT: manufactured by Okura Kogyo Co., Ltd., ESRM) 25 μm thick.

[0145] Example 8 As shown in Table 2, a release film was produced in the same manner as in Example 1, except that the first base layer was a 40 μm thick biaxially oriented polypropylene film (OPP: manufactured by Toray Industries, Inc., Torayfan (registered trademark) film #40-2500) and the second base layer was a 15 μm thick biaxially oriented polybutylene terephthalate (OPBT: manufactured by Toyobo Co., Ltd., Toyobo Ester (registered trademark) film, DE048).

[0146] Example 9 As shown in Table 2, a release film was produced in the same manner as in Example 1, except that the first substrate layer was a 15 μm thick biaxially oriented nylon film (ONy: manufactured by Unitika Ltd., Emblem (registered trademark) film ON-15) and the second substrate layer was a 15 μm thick biaxially oriented polybutylene terephthalate (OPBT: manufactured by Toyobo Co., Ltd., Toyobo Ester (registered trademark) film, DE048).

[0147] Example 10 As shown in Table 2, a release film was produced in the same manner as in Example 1, except that the first substrate layer was a 25 μm thick nylon film (CNy: manufactured by Ube Industries, Ltd., UBE Nylon (registered trademark) 1022B) produced by extrusion film formation, and the second substrate layer was a 15 μm thick biaxially oriented polybutylene terephthalate (OPBT: manufactured by Toyobo Co., Ltd., Toyobo Ester (registered trademark) film, DE048).

[0148] <Comparative Example 1> As shown in Table 2, a release film was prepared in the same manner as in Example 1, except that the substrate layer was changed to only a 15 μm thick first substrate layer made of biaxially oriented polybutylene terephthalate (OPBT: manufactured by Toyobo Co., Ltd., Toyobo Ester (registered trademark) film, DE048).

[0149] <Comparative Example 2> As shown in Table 2, a release film was prepared in the same manner as in Example 1, except that the substrate layer was changed to only a 20 μm thick first substrate layer made of biaxially oriented polybutylene terephthalate (OPBT: manufactured by Toyobo Co., Ltd., Toyobo Ester (registered trademark) film, DE048).

[0150] <Comparative Example 3> As shown in Table 2, a release film was prepared in the same manner as in Example 1, except that the substrate layer was changed to only a 50 μm thick first substrate layer made of biaxially oriented polyethylene terephthalate (OPET2: Toyobo Co., Ltd., Toyobo Ester (registered trademark) film E5100).

[0151] (3) Measurement of the physical properties of release films The resulting release film was subjected to the following measurements and evaluations, and the results are shown in Table 2.

[0152] (a) Surface roughness Ra of the release layer side of the release film Measurements were taken in accordance with JIS B0601:2013. (b) Value measured by loop stiffness test Using a loop stiffness tester (manufactured by Toyo Seiki Co., Ltd.), the stiffness strength was measured over time under the conditions of test piece size: 25 mm x 110 mm (flow direction during film formation of the release film), loop length: 62 mm, and push-in amount: 5 mm, and the maximum value during that period was taken as the "value measured by the loop stiffness test" (mN / cm). (c) Dimensional change (%) at 180°C when the temperature is increased from 30°C to 180°C at a rate of 2°C / min using thermomechanical analysis (TMA) with a tensile load of 500 mN. Measurements were taken using a TMA7100 (Hitachi High-Tech Science Corporation). (d) Storage modulus (MPa) at 180°C when dynamic mechanical analysis (DMA) was performed at a heating rate of 5°C / min and a frequency of 1Hz. Measurements were made in accordance with JIS K 7244:1998.

[0153] (4) Preparation of molded body The resulting release film was used to perform resin sealing to obtain a molded product.

[0154] First, the following granular thermosetting resin composition was prepared as a sealing resin. (raw materials) Epoxy resin 1: Biphenyl aralkyl epoxy resin (Nippon Kayaku Co., Ltd., NC-3000) Epoxy resin 2: Biphenyl type epoxy resin (Mitsubishi Chemical Corporation, YL6677) Hardener 1: Biphenylene skeleton-containing phenol aralkyl resin (manufactured by Nippon Kayaku Co., Ltd., GPH-65) Hardener 2: Formaldehyde-modified triphenylmethane phenolic resin (Air Water Corporation, HE910-20) Curing accelerator: Triphenylphosphine (Hokko Chemical Industry Co., Ltd., TPP) Inorganic filler: Fused spherical silica (Denki Kagaku Kogyo Co., Ltd., FB-950FC) Colorant: Carbon black (Mitsubishi Chemical, MA-600) Coupling agent: N-phenyl-γ-aminopropyltrimethoxysilane (Shin-Etsu Chemical Co., Ltd., KBM-573) Release agent: Carnauba wax (Nikko Fine Co., Ltd., Nikko Carnauba) (procedure) The following components were prepared: 4.5 parts by mass of the above-mentioned epoxy resin 1, 4.5 parts by mass of the epoxy resin 2, 2.8 parts by mass of curing agent 1, 2.8 parts by mass of curing agent 2, 0.4 parts by mass of a curing accelerator, 84.2 parts by mass of an inorganic filler, 0.2 parts by mass of a colorant, 0.4 parts by mass of a coupling agent, and 0.2 parts by mass of a release agent. The raw material components were then mixed at room temperature using a mixer, and then roll-kneaded while heating using two rolls at 45°C and 90°C to obtain a kneaded mixture. The kneaded mixture was then cooled and pulverized to obtain a granular thermosetting resin composition.

[0155] Next, using each release film, the thermosetting resin composition was cured (resin sealing) in the following procedure to obtain a molded body. (procedure) First, five 0.3 mm thick, 7.5 mm square semiconductor elements were bonded to an organic substrate 0.4 mm thick, 65 mm wide, and 190 mm long using silver paste, and gold wires 18 μm in diameter and 7 mm long were bonded at a pitch of 60 μm. The mold temperature of a compression molding machine (TOWA Corporation, PMC1040) was then preheated to 175°C. The organic substrate was then fixed to the upper mold so that the surface carrying the semiconductor elements faced the lower mold. The release film prepared in each example and comparative example was then placed on the lower mold with the second base layer facing the lower mold, and the mold interior was evacuated to allow the release film to conform to the lower mold. The prepared granular thermosetting resin composition (encapsulating resin composition) was then uniformly applied onto the release film. Next, immediately after supplying the encapsulating resin composition, the mold was clamped until the gap between the organic substrate and the release film was 4 mm, and at the same time, the cavity formed by the lower mold and the upper mold was depressurized to a vacuum level of 0.8 Torr in 4 seconds. Then, while continuing to depressurize, the mold was completely clamped in 12 seconds, and encapsulating molding was performed under conditions of a molding pressure of 3.9 MPa and a curing time of 90 seconds, to obtain a molded product (cured product).

[0156] (5) Evaluation of release film The following evaluations were carried out for each release film, and the results are shown in Table 2.

[0157] [Mold followability] In the above procedure, the degree of air entrapment between the mold and the release film when the release film was made to follow the mold by vacuuming was evaluated according to the following criteria. ◎: No air pockets 〇: There are small air pockets, but no practical problems △: There was a small air pocket, which reduced the degree of vacuum for film adsorption. ×: Large air pockets cause poor tracking (or evaluation is impossible)

[0158] [Dimensional stability] In the above procedure, the appearance of the cured product after it was released from the release film after molding (wrinkles, etc.) was evaluated according to the following criteria. 〇: No wrinkles or deformations, no problems △: There are some wrinkles, but no problems in practical use ×: Large wrinkles and molding defects occurred

[0159] [Mold releasability] In the above procedure, the mold release behavior when the cured product was released from the release film after molding and the state of the cured product (displacement, deflection, etc.) were evaluated according to the following criteria. 〇: No problems with demolding or molded body △: The molded product shifts or bends when released from the mold, but this does not pose a problem in practical use. ×: Unable to release from the mold, or large displacement or deflection occurred in the molded product

[0160] [Workability] In the above procedure, the state of the release film when it was placed in the molding machine was evaluated according to the following criteria. 〇: No wrinkles or creases in the film when handling, no problems △: The film may bend during handling, but this does not pose a problem in practical use. ×: Deformation occurred due to wrinkles or creases in the film during handling.

[0161] [Table 2] [Explanation of symbols]

[0162] 1 Release layer 2 Second base layer 3 First base layer 10 Release film 11 sides 21 sides

Claims

1. A release film having a multilayer structure in which a release layer, a first base layer, and a second base layer are laminated in this order, the release layer constitutes a release surface of the release film, and the second base layer constitutes a surface of the release film opposite to the release surface, the release layer contains one or more resins selected from a silicone resin, a fluororesin, a melamine resin, an epoxy resin, a phenolic resin, and an acrylic resin; the first base layer is made of a stretched or unstretched film containing one or more resins selected from a polyester resin, a polyolefin resin, and a polyamide resin; the second base layer is made of a stretched or unstretched film containing one or more resins selected from a polyester resin, a polyolefin resin, and a polyamide resin; The release film has a dimensional change rate of 4 to 40% at 180°C when the temperature is raised from 30°C to 180°C at a rate of 2°C / min under a tensile load of 500 mN by thermomechanical analysis (TMA).

2. The release film according to claim 1, The release film has a loop stiffness of 2 mN / cm or more as measured by a loop stiffness test.

3. The release film according to claim 1 or 2, A release film, wherein the first base material layer and the second base material layer are made of resin compositions having different compositions.

4. The release film according to any one of claims 1 to 3, When the release film is subjected to dynamic mechanical analysis (DMA) at a temperature rise rate of 5°C / min and a frequency of 1 Hz, the release film has a storage modulus at 180°C of 10 to 500 MPa.

5. The release film according to any one of claims 1 to 4, The surface of the release film on the release layer side has a surface roughness Ra of 0.3 to 2 μm.

6. The release film according to any one of claims 1 to 5, A release film, wherein the surface of the release film on the release layer side has a surface roughness Ra of less than 0.2 μm.

7. The release film according to any one of claims 1 to 6, A release film, wherein the total thickness of the first base material layer and the second base material layer is 25 to 70 μm.

8. The release film according to claim 1 , wherein the release film is used to be disposed between a mold and a semiconductor device in a resin-sealed semiconductor device molding process for resin-sealing the semiconductor device.

Images