JP2022108853A - release film - Google Patents

Abstract

To provide a release film that gives a molding having a good appearance.SOLUTION: The inventive release film has viscoelastic spectra determined in dynamic viscoelasticity (DMA) measurement at a temperature rise rate of 5°C/min and a frequency of 1 Hz, satisfying (a) and (b) illustrated below: (a) a storage elastic modulus at 150°C is 50 MPa or more; and (b) (E'1-E'2)[MPa]/(100-25)[°C] is 5-60 where E'1[MPa] is a storage elastic modulus at 25°C and E'2[MPa] is a storage elastic modulus at 100°C.SELECTED DRAWING: Figure 1

Description

The present invention relates to a release film.

Conventionally, various techniques have been developed in the field of release films. For example, in the field of manufacturing processes for semiconductor devices, a mold release film is placed between a mold and an object to be molded. 2. Description of the Related Art It is known to manufacture a molded body by resin-sealing a molding object on which a member is mounted (for example, Patent Literatures 1 and 2). By arranging the release film between the mold and the object to be molded, the molded product can be easily removed from the mold after resin encapsulation. A release film used for resin molding using such a mold is generally called a mold release film.

JP 2020-151949 A JP 2020-19264 A

However, wrinkles and distortions generated in the release film may be transferred to the surface of the molded product obtained using the conventional release film, and a molded product with a higher level and good appearance is obtained. There was room for improvement.

The inventors of the present invention have made intensive studies on the causes of wrinkles and distortions occurring in the release film, and have found that there are the following problems.
Usually, a suction port for evacuation is provided around the recessed cavity of the lower mold so that the mold release film is vacuum-bonded to the inner surface of the recessed cavity. After disposing the release film 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 evacuated to remove the release film. It can be vacuum-sealed to the inner surface of the cavity recess. At the time of this evacuation, the release film is also pulled into the suction port to some extent. The end of the release film may stand up. As a result, a slight gap is created between the rising edge of the release film and the lower mold, and the suction is not sufficiently performed. It became clear that wrinkles and the like tend to occur on the mold film.
Further, the upper die holds a molding object on which an electronic member such as a semiconductor element is mounted. Then, the object to be molded is clamped from above and below by a lower mold whose cavity recess is filled with a resin material for sealing and an upper mold to which the object to be molded is fixed. Resin mold. At this time, pressure is applied so as to compress the sealing resin material by raising the pedestal of the lower mold. At this time, since the depth of the cavity becomes shallow, a slight gap is generated between the release film and the inner surface of the recessed portion of the cavity. Therefore, it has become clear that deformation occurs in the release film, which causes distortion and wrinkles.

Therefore, the inventors of the present invention conducted further intensive studies from the viewpoint of solving such problems, and as an index for controlling the properties of the release film, focused on the viscoelastic spectrum under predetermined conditions, A new index for the ratio and the equilibrium elastic modulus was devised. By controlling each of these indicators, the release film can return to its original shape against the elongation (elastic recovery) while obtaining sufficient elongation (deformation) against the stress at the time of fitting the mold. The present inventors have completed the present invention based on the finding that the occurrence of wrinkles can be suppressed. Moreover, it was found that by controlling such a new index, it is possible to effectively suppress the occurrence of wrinkles and distortion of the release film, not limited to the application in the production method as described above.

According to the invention,
Provided is a release film whose viscoelastic spectrum measured under the conditions of a temperature increase rate of 5° C./min and a frequency of 1 Hz in dynamic viscoelasticity (DMA) measurement satisfies the following (a) and (b).
(a) a storage modulus at 150° C. of 50 MPa or more;
(b) When the storage modulus at 25° C. is E′1 [MPa] and the storage modulus at 100° C. is E′2 [MPa], (E′1−E′2) [MPa]/(100− 25) [°C] is 5 to 60;

Moreover, according to the present invention,
A release film is provided whose viscoelastic spectrum measured under the conditions of a temperature increase rate of 5° C./min and a frequency of 1 Hz in dynamic viscoelasticity (DMA) measurement satisfies the following (c).
(c) It has an equilibrium elastic modulus at least in the range of 200° C. or higher and 250° C. or lower, and the equilibrium elastic modulus is 1.0 MPa or higher.

ADVANTAGE OF THE INVENTION According to this invention, the release film which suppresses generation|occurrence|production of wrinkles and distortion of a release film, and can obtain a molded object with a favorable external appearance is provided.

FIG. 2 is a cross-sectional view schematically showing the cross section of the release film of the present embodiment; FIG. 4 is a graph showing an example of the equilibrium elastic modulus of the release film of the present embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
In all the drawings, the same constituent elements are denoted by the same reference numerals, and the description thereof will be omitted as appropriate. In order to avoid complication, (i) when there are a plurality of the same components in the same drawing, only one of them is given a reference numeral and not all of them, and (ii) in particular the figure 2 onward, the same constituent elements as those in FIG. 1 may not be denoted by reference numerals. All drawings are for illustration purposes only. The shape and dimensional ratio of each member in the drawings do not necessarily correspond to the actual article.

In this specification, the notation "a to b" in the description of numerical ranges means from a to b, unless otherwise specified. For example, "1 to 5% by mass" means "1% by mass or more and 5% by mass or less".
Moreover, in this specification, the MD direction represents the machine direction and intends the flow direction of the resin, and the TD direction represents the transverse direction and intends the vertical direction.

<Release film>
The release film of the present embodiment may have a single-layer structure, and at least one surface of the release film, that is, a release layer serving as a release surface, and a substrate made of a material different from the release layer It may be a multi-layer structure including a layer. A multi-layer structure is preferable from the viewpoint of achieving both sufficient elongation and elastic recovery against elongation at a higher level. Details will be described below, taking as an example the case where the release film has a multilayer structure.

FIG. 1 is a cross-sectional view schematically showing a cross section of the release film of this embodiment.
As shown in FIG. 1 , the release film 11 of this embodiment includes a base layer 2 and a release layer 1 laminated on the base layer 2 .

The release film 11 of the present embodiment has a viscoelastic spectrum measured under the conditions of a temperature increase rate of 5 ° C./min and a frequency of 1 Hz in dynamic viscoelasticity (DMA) measurement. Fulfill.
(a) a storage modulus at 150° C. of 50 MPa or more;
(b) When the storage modulus at 25° C. is E′1 [MPa] and the storage modulus at 100° C. is E′2 [MPa], (E′1−E′2) [MPa]/(100− 25) [°C] is 5 to 60;

Alternatively, the release film 11 of the present embodiment has a viscoelastic spectrum measured under conditions of a temperature increase rate of 5° C./min and a frequency of 1 Hz in dynamic viscoelasticity (DMA) measurement, which satisfies the following (c).
(c) It has an equilibrium elastic modulus at least in the range of 200° C. or higher and 250° C. or lower, and the equilibrium elastic modulus is 1 MPa or higher.

As a result, while sufficient elongation is obtained, the shape recoverability against elongation can be obtained at the same time, and the occurrence of wrinkles and distortion in the release film 11 can be effectively suppressed. Although the details of this reason are not clear, it is presumed as follows.

First, according to the index (a), by setting the storage elastic modulus of the release film 11 at 150° C. to the lower limit or more, even when the release film 11 is exposed to high temperatures during use, an appropriate strength is maintained. , dimensional stability and shape recoverability are obtained, so it is assumed that wrinkles and distortion are less likely to occur in the release film 11 . In addition, according to the index (b), from the room temperature state before use of the release film 11, the release film 11 follows the mold in the process of being placed in the mold and heated, while moderate elongation against stress. is assumed to be obtained. Then, by simultaneously controlling the indicators (a) and (b), it is possible to achieve a high level of balance between sufficient elongation and recovery from elongation, and as a result, when using the release film It is considered that wrinkles and distortion can be effectively suppressed.

In addition, the equilibrium elastic modulus of (c) is intended to allow the release film 11 to retain its shape even in the range of 200° C. or higher and 250° C. or lower. is assumed to be obtained. That is, when the release film 11 of the present embodiment is heated, for example, as shown in FIG. be done.
In other words, when the release film 11 is heated before use and when it is brought into close contact with the mold, the shape of the release film 11 is maintained even during the subsequent thermocompression bonding while obtaining appropriate elasticity and elongation. Shape recovery is obtained, and a high level of balance between sufficient elongation and recovery against elongation can be achieved, and as a result, wrinkles and distortion that can occur when the release film is used can be effectively suppressed. Conceivable. In addition, by having an equilibrium elastic modulus at 250° C. or less, it becomes easier to improve mold releasability, and it becomes easier to obtain good dimensional stability and interlaminar strength.

In (a) above, the storage elastic modulus at 150° C. is 50 MPa or more, preferably 50 MPa to 500 MPa, more preferably 100 MPa to 450 MPa.
In the above (b), (E′1−E′2)[Pa]/(100−25)[° C.] is 5 to 60, preferably 10 to 55.

In (c) above, the equilibrium elastic modulus in the range of 200° C. to 250° C. is 1.0 MPa or more, preferably 2 MPa to 10 MPa.

The release film 11 of the present embodiment further has a viscoelastic spectrum measured at a temperature increase rate of 5° C./min and a frequency of 1 Hz in dynamic viscoelasticity (DMA) measurement, which satisfies the following condition (d). is preferred.
(d) Loss modulus/storage modulus (loss tangent) at 180° C. in the MD direction is 0.05 or more and 0.2 or less, preferably 0.05 to 0.15.
By setting the loss elastic modulus/storage elastic modulus (loss tangent) within the above numerical range, a good balance between elasticity and elongation can be maintained. Even if there is, it is presumed that the release film 11 can recover its shape after being partially stretched, and that the occurrence of wrinkles and distortion of the entire release film 11 can be easily suppressed.

In this embodiment, the dynamic viscoelasticity (DMA) measurement can be performed using a commercially available dynamic viscoelasticity measuring device (eg, "DMS6100" manufactured by SII) under the following measurement conditions.
(Measurement condition)
・Frequency: 1Hz
・Temperature range: 20 to 260°C
・Temperature increase rate: 5°C/min
・Test piece: about 10mm width ・Test mode: tension

The release film 11 of the present embodiment preferably further satisfies the following (e).
(e) The 180° C. 5% tensile strength (5% modulus) of the release film is 1 MPa or more and 5 MPa or less, preferably 1-4, more preferably 1.5-3.
It is presumed that the index (e) makes it easier to control the ability of the release film 11 to return to its original shape against elongation.

The indicators (a) to (e) above are obtained by appropriately selecting and combining known methods such as the type and amount of raw materials of the release layer 1, the method of preparing the raw materials, and the method of manufacturing the release film 11. , can be realized by using a method different from the conventional method.
Among these, for example, when a silicone resin is selected as the raw material of the release layer 1, the type and blending ratio of the silicone resin, the crosslink density and crosslink structure of the resin, etc. are appropriately controlled, and the blending of the inorganic filler is performed. Improving the ratio and the dispersibility of the inorganic filler are factors for setting the above index within the desired numerical range.
By adjusting the curing conditions, temperature, and time for obtaining the release layer 1, the crosslink density, crosslink structure, etc. of the resin can be appropriately controlled, and the above indices can be set within desired numerical ranges. Further, for example, in the manufacturing process of a release film, when sandwiching between substrates to produce, it is also possible to change the surface roughness depending on the surface condition. In addition, it is effective to control the combination of materials for the release layer 1 and the substrate layer 2 .

The thickness of the release film 11 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.

Each layer included in the release film 11 of the present embodiment will be described below.

[Release layer]
The release layer 1 forms one surface of the release film 11 and has a release surface 3 .

The thickness of the release layer 1 is preferably 1 μm or more and 150 μm or less, more preferably 2 μm or more and 100 μm or less, further preferably 5 μm or more and 50 μm or less, and further preferably 30 μm or less.
By setting the thickness of the release layer 1 to the above lower limit or more, the rigidity of the release film 11 is increased, and excessive deformation and wrinkles can be easily suppressed. As a result, mold followability and dimensional stability can be obtained. On the other hand, by setting the thickness of the release layer 1 to the upper limit value or less, the rigidity of the release film 11 can be controlled, and a good balance between mold followability and mold releasability can be achieved.

The release surface 3 of the release layer 1 is the surface that comes into contact with the sealing resin to be described later when the release film 11 is used. The surface roughness Rz of the release surface 3 is preferably 0.05-10 μm, more preferably 0.08-7 μm.
By setting the surface roughness Rz of the release surface 3 to the above lower limit or more, it is possible to achieve a good balance between the releasability and mold followability during molding. On the other hand, by setting the surface roughness Rz of the release surface 3 to the above upper limit value or less, the release property can be improved while maintaining the mold followability and dimensional stability.

The method of controlling the surface roughness of the release surface 3 includes transferring an embossed pattern to the film using an embossed roll in the production process of the release film, blending particles into the material of the release layer, and the like. , can be adjusted in a known manner.
The surface roughness Rz of the release layer 1 is measured according to JIS B0601:2013.

The release layer 1 is composed of a first resin composition containing a resin.
The resin contained in the first resin composition may include, for example, one or more selected from among silicone resins, fluororesins, polyolefin resins, polyester resins, melamine resins, epoxy resins, and polyamide resins. From the viewpoint of obtaining a release surface 3 with good release properties, it is more preferable to include one or more selected from silicone resins, fluororesins, melamine resins, epoxy resins and polyolefin resins. Among them, silicone resin is more preferable from the viewpoint of achieving both deformation and recovery.

(Silicone resin)
The silicone resin is not particularly limited. For example, compounds containing two or more siloxane bonds (--Si--O--) such as various known or commercially available siloxane-based polymers can be used.

The silicone resin preferably contains one or two selected from, for example, vinyl group-containing organopolysiloxane (A) and organohydrogenpolysiloxane (B). As a result, rubber-like properties such as elasticity and compressibility of silicone can be obtained, making it easier to obtain sufficient elongation of the release film and shape recovery against elongation.

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

The vinyl group-containing linear organopolysiloxane (A1) has a linear structure and contains vinyl groups, and the vinyl groups serve as crosslinking points during curing.

The vinyl group content of the vinyl group-containing linear organopolysiloxane (A1) is not particularly limited, but for example, it preferably has two or more vinyl groups in the molecule and is 15 mol % or less. . As a result, the amount of vinyl groups in the vinyl group-containing linear organopolysiloxane (A1) is optimized, and a network can be reliably formed with each component described later.

In the present specification, the vinyl group content is the mol % of the vinyl group-containing siloxane units when the total units constituting the vinyl group-containing linear organopolysiloxane (A1) are taken as 100 mol %. . However, one vinyl group is considered to be one vinyl group-containing siloxane unit.

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

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.

As the vinyl group-containing linear organopolysiloxane (A1), the heat resistance, flame retardancy, chemical stability, etc. of the resulting silicone rubber can be improved by using those having the degree of polymerization and specific gravity within the ranges described above. can be improved.

As the vinyl group-containing linear organopolysiloxane (A1), those having a structure represented by the following formula (1) are preferable.

In formula (1), R ¹ is a substituted or unsubstituted alkyl group, alkenyl group, aryl group, or a hydrocarbon group of a combination thereof having 1 to 10 carbon atoms. The alkyl group having 1 to 10 carbon atoms includes, for example, methyl group, ethyl group, propyl group, etc. Among them, methyl group is preferred. The alkenyl group having 1 to 10 carbon atoms includes, for example, vinyl group, allyl group, butenyl group, etc. Among them, vinyl group is preferred. The aryl group having 1 to 10 carbon atoms includes, for example, a phenyl group.

R ² is a substituted or unsubstituted alkyl group, alkenyl group, aryl group having 1 to 10 carbon atoms, or a hydrocarbon group combining these. The alkyl group having 1 to 10 carbon atoms includes, for example, methyl group, ethyl group, propyl group, etc. Among them, methyl group is preferable. Examples of alkenyl groups having 1 to 10 carbon atoms include vinyl groups, allyl groups and butenyl groups. Examples of the aryl group having 1 to 10 carbon atoms include a phenyl group.

R ³ is a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms, an aryl group, or a hydrocarbon group combining these. The alkyl group having 1 to 8 carbon atoms includes, for example, methyl group, ethyl group, propyl group, etc. Among them, methyl group is preferable. Examples of the aryl group having 1 to 8 carbon atoms include a phenyl group.

Furthermore, examples of substituents for R ¹ and R ² in formula (1) include methyl group and vinyl group, and examples of substituents for R ³ include methyl group.

In formula (1), a plurality of R ¹ are independent of each other and may be different or the same. Furthermore, the same applies to R ² and R ³ .

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

Further, specific structures of the vinyl group-containing linear organopolysiloxane (A1) represented by formula (1) include, for example, those represented by the following formula (1-1).

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

The vinyl group-containing linear organopolysiloxane (A1) is a first vinyl group-containing linear organopolysiloxane having a vinyl group content of 2 or more vinyl groups in the molecule and not more than 0.4 mol %. It may contain organopolysiloxane (A1-1). The vinyl group content of the first vinyl group-containing linear organopolysiloxane (A1-1) may be 0.1 mol % or less.

Further, the vinyl group-containing linear organopolysiloxane (A1) is the first vinyl group-containing linear organopolysiloxane (A1-1) and the second vinyl group-containing linear organopolysiloxane (A1-1) having a vinyl group content of 0.5 to 15 mol%. and a vinyl group-containing linear organopolysiloxane (A1-2).

As crude rubber, which is a raw material of silicone rubber, a first vinyl group-containing linear organopolysiloxane (A1-1) and a second vinyl group-containing linear organopolysiloxane having a high vinyl group content (A1-2 ), the vinyl groups can be unevenly distributed, and the crosslink density can be more effectively formed in the crosslink network of the silicone rubber. As a result, the tear strength of the release film can be increased more effectively, and the dimensional stability and transferability can be easily controlled.

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

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

Furthermore, when combining the first vinyl group-containing linear organopolysiloxane (A1-1) and the second vinyl group-containing linear organopolysiloxane (A1-2), (A1-1) and (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 80:20 to 90: 10 is more preferred.

The first and second vinyl group-containing linear organopolysiloxanes (A1-1) and (A1-2) may be used singly or in combination of two or more. good.

Also, the vinyl group-containing organopolysiloxane (A) may contain a vinyl group-containing branched organopolysiloxane (A2) having a branched structure.

<<Organohydrogenpolysiloxane (B)>>
Organohydrogenpolysiloxane (B) is classified into linear organohydrogenpolysiloxane (B1) having a linear structure and branched organohydrogenpolysiloxane (B2) having a branched structure. Either or both may be included.

The linear organohydrogenpolysiloxane (B1) has a linear structure and a structure (≡Si—H) in which hydrogen is directly bonded to Si, and is the vinyl group-containing organopolysiloxane (A). It is a polymer that undergoes a hydrosilylation reaction with vinyl groups other than vinyl groups and vinyl groups of components contained in the raw material of the release layer 1 to crosslink these components.

The molecular weight of the linear organohydrogenpolysiloxane (B1) is not particularly limited.

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

Also, the straight-chain organohydrogenpolysiloxane (B1) generally preferably does not have a vinyl group. Thereby, it is possible to accurately prevent the progress of the cross-linking reaction in the molecule of the linear organohydrogenpolysiloxane (B1).

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

In formula (2), R ⁴ is a substituted or unsubstituted alkyl group, alkenyl group, aryl group having 1 to 10 carbon atoms, a hydrocarbon group combining these groups, or a hydride group. The alkyl group having 1 to 10 carbon atoms includes, for example, methyl group, ethyl group, propyl group, etc. Among them, methyl group is preferred. Examples of alkenyl groups having 1 to 10 carbon atoms include vinyl groups, allyl groups and butenyl groups. Examples of the aryl group having 1 to 10 carbon atoms include a phenyl group.

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

In formula (2), a plurality of R ⁴ are independent of each other and may be different from each other or may be the same. The ^same is true for R5. However, at least two or more of the plurality of R ⁴ and R ⁵ are hydride groups.

R ⁶ is a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms, an aryl group, or a hydrocarbon group combining these. The alkyl group having 1 to 8 carbon atoms includes, for example, methyl group, ethyl group, propyl group, etc. Among them, methyl group is preferred. Examples of the aryl group having 1 to 8 carbon atoms include a phenyl group. A plurality of R ⁶ are independent from each other and may be different from each other or may be the same.

Examples of substituents for R ⁴ , R ⁵ and R ⁶ in formula (2) include methyl group and vinyl group, and methyl group is preferred from the viewpoint of preventing intramolecular cross-linking reaction.

Further, m and n are the numbers of repeating units constituting the linear organohydrogenpolysiloxane (B1) represented by formula (2), m is an integer of 2 to 150, and n is an integer of 2 to 150. is. Preferably, m is an integer from 2-100 and n is an integer from 2-100.

In addition, linear organohydrogenpolysiloxane (B1) may be used individually by 1 type, and may be used in combination of 2 or more types.

Since the branched organohydrogenpolysiloxane (B2) has a branched structure, it is a component that forms regions with a high crosslink density and greatly contributes to the formation of a loose and dense crosslink density structure in the silicone rubber system. Further, like the linear organohydrogenpolysiloxane (B1), it has a structure (≡Si—H) in which hydrogen is directly bonded to Si, and in addition to the vinyl group of the vinyl group-containing organopolysiloxane (A), It is a polymer that undergoes a hydrosilylation reaction with the vinyl groups of the components contained in the raw material of the mold layer 1 to crosslink these components.

Further, the branched organohydrogenpolysiloxane (B2) has a specific gravity in the range of 0.9 to 0.95.

Furthermore, it is generally preferred that the branched organohydrogenpolysiloxane (B2) does not have a vinyl group. Thereby, it is possible to accurately prevent the progress of the cross-linking reaction in the molecule of the branched organohydrogenpolysiloxane (B2).

As the branched organohydrogenpolysiloxane (B2), those represented by the following average compositional formula (c) are preferred.

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, m is the number of H _a (R ⁷ ) _3-a SiO _1/2 units, n is SiO _4/ is a number of ₂ units)

In formula (c), R ⁷ is a monovalent organic group, preferably a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, an aryl group, or a hydrocarbon group combining these. The alkyl group having 1 to 10 carbon atoms includes, for example, methyl group, ethyl group, propyl group, etc. Among them, methyl group is preferred. Examples of the aryl group having 1 to 10 carbon atoms include a phenyl group.

In formula (c), a is the number of hydride groups (hydrogen atoms directly bonded to Si) and is an integer in the range of 1-3, preferably 1.

In formula (c), m is the number of H _a (R ⁷ ) _3-a SiO _1/2 units, and n is the number of SiO _4/2 units.

The branched organohydrogenpolysiloxane (B2) has a branched structure. The linear organohydrogenpolysiloxane (B1) and the branched organohydrogenpolysiloxane (B2) differ in that their structures are linear or branched. The number of bound alkyl groups R (R/Si) is 1.8 to 2.1 for the linear organohydrogenpolysiloxane (B1) and 0.8 to 1 for the branched organohydrogenpolysiloxane (B2). .7 range.

Since the branched organohydrogenpolysiloxane (B2) has a branched structure, for example, when heated to 1000° C. at a heating rate of 10° C./min in a nitrogen atmosphere, the residual amount is 5% or more. becomes. On the other hand, since the straight-chain organohydrogenpolysiloxane (B1) is straight-chain, the amount of residue after heating under the above conditions is almost zero.

Further, specific examples of the branched organohydrogenpolysiloxane (B2) include those having a structure represented by the following formula (3).

In formula (3), R ⁷ is a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms, an aryl group, a hydrocarbon group combining these, or a hydrogen atom. The alkyl group having 1 to 8 carbon atoms includes, for example, methyl group, ethyl group, propyl group, etc. Among them, methyl group is preferable. Examples of the aryl group having 1 to 8 carbon atoms include a phenyl group. Examples of the substituent of ^R7 include a methyl group and the like.

In formula (3), a plurality of R ⁷ are independent of each other and may be different from each other or may be the same.

In formula (3), "--O--Si.ident." represents that Si has a branched structure extending three-dimensionally.

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

Moreover, 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, linear organohydrogenpolysiloxane (B1) and branched organohydrogenpolysiloxane (B2) are ) is preferably 0.5 to 5 mol, more preferably 1 to 3.5 mol, of the total hydride group amount. As a result, a crosslinked network is reliably formed between the linear organohydrogenpolysiloxane (B1), the branched organohydrogenpolysiloxane (B2), and the vinyl group-containing linear organopolysiloxane (A1). can be made

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

(polyolefin resin)
The above polyolefin resin is a resin having structural units derived from α-olefins such as ethylene, propylene and butene, and known 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 (mLLPE); 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 resin; ethylene-vinyl alcohol copolymer (EVOH), cyclic olefin resin (COP) and the like. These may be used alone or in combination of two or more.

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

(Epoxy resin)
As the above epoxy resin, it is possible to use all monomers, oligomers and polymers having two or more epoxy groups in one molecule, regardless of their molecular weight and molecular structure. Specific examples of such epoxy resins include 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-phenylenediisoprediene) bisphenol type epoxy resin), bisphenol P type epoxy resin (4,4'-(1,4-phenylenediisoprediene) bisphenol type epoxy resin), bisphenol Bisphenol-type epoxy resins such as Z-type epoxy resins (4,4′-cyclohexidienebisphenol-type epoxy resins); Novolak type epoxy resins such as novolac type epoxy resins and novolak type epoxy resins having a condensed ring aromatic hydrocarbon structure; biphenyl type epoxy resins; xylylene type epoxy resins and aralkyl type epoxy resins such as biphenyl aralkyl type epoxy resins; naphthylene ether epoxy resin, naphthol-type epoxy resin, naphthalene-type epoxy resin, naphthalene diol-type epoxy resin, difunctional to tetra-functional epoxy-type naphthalene resin, binaphthyl-type epoxy resin, naphthalene aralkyl-type epoxy resin, and other epoxy resins having a naphthalene skeleton; anthracene type epoxy resin; phenoxy type epoxy resin; dicyclopentadiene type epoxy resin; norbornene type epoxy resin; adamantane type epoxy resin; fluorene type epoxy resin, phosphorus-containing epoxy resin, alicyclic epoxy resin, aliphatic linear epoxy resin, bisphenol Heterocyclic epoxy resins such as A novolac-type epoxy resin, bixylenol-type epoxy resin, triphenolmethane-type epoxy resin, trihydroxyphenylmethane-type epoxy resin, tetraphenylolethane-type epoxy resin, and triglycidyl isocyanurate; , N', N'-tetraglycidylmetaxylenediamine, N,N,N',N'-tetraglycidylbisaminomethylcyclohexane, glycidylamines such as N,N-diglycidylaniline, glycidyl (meth) acrylate and Copolymers with compounds having ethylenically unsaturated double bonds, epoxy resins with butadiene structures, bisphenol It may contain one or more selected from glycidyl-etherified products, diglycidyl-etherified products of naphthalenediol, and glycidyl-etherified products of phenols.

(polyamide resin)
Examples of the above polyamide resins include aliphatic polyamides and aromatic polyamides. Specific examples of aliphatic polyamides include polyamide 6, polyamide 6,6, polyamide 6-6,6 copolymer, polyamide 11, polyamide 12 and the like. Specific examples of aromatic polyamides include polyamide 61, polyamide 66/6T, polyamide 6T/6 and polyamide 12/6T.

(melamine resin)
The above melamine resin is obtained, for example, by polycondensing a melamine compound and formaldehyde under neutral or weak alkali conditions. Specific examples include alkylated melamine resins such as methylated melamine resins and butylated melamine resins, methylolated melamine resins, and alkyl-etherified melamine resins.

[others]
The first resin composition may contain other components in addition to the resins described above, as long as the properties of the release film 11 are not impaired. Other components include, but are not limited to, solvents, inorganic fillers, coupling agents, antistatic agents, leveling agents, dispersants, pigments, dyes, antioxidants, flame retardants, thermal conductivity improvers, etc. be able to. Representative components are described below.

(solvent)
The first resin composition) may contain, for example, a solvent depending on the manufacturing method of the release layer 1 . When a solvent is included, 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 include water, aliphatic hydrocarbons such as pentane, hexane, cyclohexane, heptane, methylcyclohexane, ethylcyclohexane, octane, decane, dodecane, and tetradecane; benzene, toluene, ethylbenzene, and xylene. , trifluoromethylbenzene, aromatic hydrocarbons such as benzotrifluoride; diethyl ether, diisopropyl ether, dibutyl ether, cyclopentyl methyl ether, cyclopentyl ethyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, 1,4- ethers such as 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 dimethylsulfoxide and diethylsulfoxide; These may be used alone or in combination of two or more.

(Inorganic filler)
In this embodiment, the first resin composition may contain an inorganic filler. As a result, fine irregularities are formed on the surface of the release layer 1, and the releasability can be improved.
Examples of inorganic fillers include, but are not limited to, diatomaceous earth, iron oxide, titanium oxide, barium oxide, magnesium oxide, cerium oxide, magnesium carbonate, zinc carbonate, glass wool, mica, calcium carbonate, zinc oxide, alumina, and crystalline silica. , amorphous silica, fused silica, and zeolite. Among them, one or more selected from the group consisting of calcium carbonate, zinc oxide, alumina, crystalline silica, amorphous silica, fused silica, and zeolite is preferred.
Further, fumed silica (flame silica), calcined silica, precipitated silica, etc. may be used depending on the method of synthesizing silica.
These inorganic fillers may be used alone or in combination of two or more.

The inorganic filler preferably has a BET specific surface area of, for example, 50 to 400 m ² /g, more preferably 100 to 400 m ² /g.
Also, the average primary particle size of the inorganic filler is preferably, for example, 1 to 100 nm, more preferably about 5 to 20 nm.

By using an inorganic filler having a specific surface area and an average particle diameter within the range, the hardness and mechanical strength of the formed release layer 1 are improved, and releasability, mold followability, and dimensional stability are improved. Helps improve gender balance.

(Silane coupling agent)
The silane coupling agent can have hydrolyzable groups. The hydrolyzable group is hydrolyzed with water to form a hydroxyl group, and the hydroxyl group undergoes a dehydration condensation reaction with the hydroxyl group on the surface of the inorganic filler, thereby modifying the surface of the inorganic filler.

Also, the silane coupling agent can include a silane coupling agent having a hydrophobic group. As a result, since the hydrophobic group is imparted to the surface of the inorganic filler, the cohesive force of the inorganic filler is reduced in the first resin composition and thus in the release layer 1 (in the case of silica particles, the silanol group aggregation due to hydrogen bonding is reduced), and as a result, it is presumed that the dispersibility of the inorganic filler in the release layer 1 is improved. This increases the interface between the inorganic filler and the rubber matrix, increasing the reinforcing effect of the inorganic filler. Furthermore, it is presumed that the slipperiness of the inorganic filler in the matrix is improved when the rubber matrix is deformed. Further, by improving the dispersibility and slipperiness of the inorganic filler, the mechanical strength (for example, mold followability, dimensional stability, etc.) of the release layer 1 by the inorganic filler is improved.

Furthermore, the silane coupling agent can contain a silane coupling agent having a vinyl group. Thereby, a vinyl group is introduced to the surface of the inorganic filler. Therefore, when the release layer 1 is cured, that is, the vinyl group of the vinyl group-containing organopolysiloxane (A) and the hydride group of the organohydrogenpolysiloxane (B) undergo a hydrosilylation reaction, resulting in When a network (crosslinked structure) is formed, the vinyl group of the inorganic filler (in the case of silica particles) also participates in the hydrosilylation reaction with the hydride group of the organohydrogenpolysiloxane (B). Inorganic fillers also come to be incorporated therein. As a result, it is possible to reduce the hardness and increase the modulus of the release layer 1 to be formed.

As the silane coupling agent, a silane coupling agent having a hydrophobic group and a silane coupling agent having a vinyl group can be used in combination.

Examples of silane coupling agents include those represented by the following formula (4).

_Yn -Si-(X) _4-n (4)
In the above formula (4), n represents an integer of 1-3. Y represents a functional group having a hydrophobic group, a hydrophilic group or a vinyl group, and when n is 1 it is a hydrophobic group, and when n is 2 or 3 at least one of It is a hydrophobic group. X represents a hydrolyzable group.

The hydrophobic group is an alkyl group having 1 to 6 carbon atoms, an aryl group, or a hydrocarbon group having a combination thereof, and examples thereof include a methyl group, an ethyl group, a propyl group, a phenyl group, etc. Among them, a methyl group is preferred.

Moreover, the hydrophilic group includes, for example, a hydroxyl group, a sulfonic acid group, a carboxyl group, a carbonyl group, etc. Among them, a hydroxyl group is preferable. The hydrophilic group may be contained as a functional group, but is preferably not contained from the viewpoint of imparting hydrophobicity to the silane coupling agent.

Furthermore, the hydrolyzable group includes an alkoxy group such as a methoxy group and an ethoxy group, a chloro group, a silazane group, and the like. groups are preferred. A compound having a silazane group as a hydrolyzable group has two structures of (Y _n —Si—) in the above formula (4) due to its structural characteristics.

Specific examples of the silane coupling agent represented by the above formula (4) include, for example, those having a hydrophobic group as a functional group, such as methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, alkoxysilanes such as dimethyldiethoxysilane, phenyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, decyltrimethoxysilane; chlorosilanes such as chlorosilane, trimethylchlorosilane and phenyltrichlorosilane; hexamethyldisilazane; alkoxysilanes such as ethoxysilane, methacryloxypropylmethyldimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, vinylmethyldimethoxysilane; chlorosilanes such as vinyltrichlorosilane, vinylmethyldichlorosilane; and divinyltetramethyldisilazane. Among them, considering the above description, hexamethyldisilazane is particularly preferable as one having a hydrophobic group, and divinyltetramethyldisilazane as one having a vinyl group.

(catalyst)
The first resin composition may contain a catalyst when the release layer 1 is formed by a curing reaction. Catalysts include platinum or platinum compounds. As the platinum or platinum compound, known ones can be used, for example, platinum black, platinum supported on silica, carbon black, etc., chloroplatinic acid or an alcohol solution of chloroplatinic acid, chloroplatinic acid and Complex salts of olefins, complex salts of chloroplatinic acid and vinyl siloxane, and the like are included. Platinum or a platinum compound may be used individually by 1 type, and may be used in combination of 2 or more type.

In addition, in the present embodiment, although the content ratio of each component of the first resin composition is not particularly limited, it is set as follows, for example.

In the present embodiment, the upper limit of the content of the inorganic filler may be, for example, 60 parts by weight or less, preferably 50 parts by weight or less with respect to 100 parts by weight of the total amount of the vinyl group-containing organopolysiloxane (A). well, more preferably 40 parts by weight or less. As a result, mechanical strength such as hardness and tear strength of the release film 11 can be improved, and the balance among releasability, mold followability, and dimensional stability can be improved. Moreover, the lower limit of the content of the inorganic filler is not particularly limited to 100 parts by weight of the total amount of the vinyl group-containing organopolysiloxane (A), but may be, for example, 10 parts by weight or more.

The silane coupling agent preferably contains, for example, 5 parts by weight or more and 100 parts by weight or less of the silane coupling agent per 100 parts by weight of the vinyl group-containing organopolysiloxane (A), and 5 parts by weight or more and 40 parts by weight. It is more preferable to contain it in a proportion of parts by weight or less. Thereby, the dispersibility of the inorganic filler in the release layer 1 can be reliably improved.

Specifically, the content of the organohydrogenpolysiloxane (B) is, for example, 0.5 per 100 parts by weight of the total amount of the vinyl group-containing organopolysiloxane (A), the inorganic filler, and the silane coupling agent. It is preferably contained in a proportion of 0.8 to 15 parts by weight, preferably 0.8 to 15 parts by weight. When the content of (B) is within the above range, a more effective curing reaction may be possible.

[Method for manufacturing release layer]
Next, a method for manufacturing the release layer 1 of this embodiment will be described.
As a method for producing the release layer 1 of the present embodiment, the release layer 1 can be obtained by preparing the first resin composition, forming the first resin composition into a film, and curing the film.
Details will be described below.

First, each component of the first resin composition is uniformly mixed by any kneading device to prepare the first resin composition.
In the following, the details will be described with an example using a silicone resin as the resin.

[1] For example, a vinyl group-containing organopolysiloxane (A), an inorganic filler, and a silane coupling agent are weighed in predetermined amounts, and then kneaded by an arbitrary kneading device to obtain a kneaded product.

Moreover, when obtaining this kneaded material, you may add water as needed. This allows the reaction between the silane coupling agent and the inorganic filler to proceed more reliably.

Further, the kneading is preferably performed through a first step of heating at a first temperature and a second step of heating at a second temperature. As a result, in the first step, the surface of the inorganic filler can be treated with the coupling agent, and in the second step, the by-product produced by the reaction between the inorganic filler and the coupling agent is removed from the kneaded product. You can definitely remove it from the inside. After that, if necessary, the component (A) may be added to the obtained kneaded product and further kneaded. This can improve the familiarity of the components of the kneaded product.

The first temperature is preferably, for example, about 40 to 120.degree. C., and more preferably, for example, about 60 to 90.degree. The second temperature is, for example, preferably about 130 to 210.degree. C., more preferably about 160 to 180.degree.

Moreover, the atmosphere in the first step is preferably an inert atmosphere such as a nitrogen atmosphere, and the atmosphere in the second step is preferably a reduced-pressure atmosphere.

Furthermore, the time for the first step is preferably, for example, about 0.3 to 1.5 hours, more preferably about 0.5 to 1.2 hours. The time for the second step is, for example, preferably about 0.7 to 3.0 hours, more preferably about 1.0 to 2.0 hours.

By setting the first step and the second step under the above conditions, the above effect can be obtained more significantly.

[2] Next, the organohydrogenpolysiloxane (B) and the catalyst are weighed in predetermined amounts, and then each component is kneaded with the kneaded product prepared in the above step [1] using any kneading device. By doing so, a first resin composition is obtained. The obtained first resin composition may be a paste containing a solvent.

When kneading each component (B) and the catalyst, the kneaded product prepared in advance in the above step [1] and the organohydrogenpolysiloxane (B) are mixed together in the above step [1]. and the catalyst are kneaded, and then each kneaded product is preferably kneaded. As a result, each component can be reliably dispersed in the first resin composition without allowing the reaction between the vinyl group-containing organopolysiloxane (A) and the organohydrogenpolysiloxane (B) to proceed.

The temperature at which each component (B) and the catalyst are kneaded is preferably about 10 to 70° C., more preferably about 25 to 30° C., as the set temperature of the rolls.

Further, the kneading time is preferably about 5 minutes to 1 hour, more preferably about 10 to 40 minutes.

In the steps [1] and [2], the reaction between the vinyl group-containing organopolysiloxane (A) and the organohydrogenpolysiloxane (B) proceeds more accurately by setting the temperature within the above range. can be prevented or suppressed; Further, by setting the kneading time within the above range in steps [1] and [2], each component can be more reliably dispersed in the first resin composition.

The kneading device used in steps [1] and [2] is not particularly limited, but for example, a kneader, two rolls, a Banbury mixer (continuous kneader), a pressure kneader, etc. can be used.

In step [2], a reaction inhibitor such as 1-ethynylcyclohexanol may be added to the kneaded product. As a result, even if the temperature of the kneaded product is set to a relatively high temperature, the progress of the reaction between the vinyl group-containing organopolysiloxane (A) and the organohydrogenpolysiloxane (B) can be more accurately prevented or suppressed. be able to.

[3] Next, the first resin composition obtained in step [2] may be made into a paste by dissolving it in a solvent.

[4] Next, the release layer 1 is formed by processing the first resin composition into a film and curing it.
Specifically, the first resin composition is molded into a film by extrusion molding, calendar molding, press molding, coating, or the like. The surface shape of the roll or the like may be transferred or embossed during film formation.

In the present embodiment, the curing step of the first resin composition includes, for example, heating at 100 to 250° C. for 1 to 30 minutes (primary curing), followed by post-baking at 100 to 250° C. for 1 to 4 hours (secondary curing). ).

Through the steps described above, the release layer 1 using the first resin composition of the present embodiment, that is, the release film 11 is obtained.

[Base material layer 2]
In the release film 11 of the present embodiment, the base layer 2 is provided with appropriate rigidity in order to exhibit the shape stability and production stability of the release film 11 and the release function of the release layer. used from

The thickness of the substrate layer 2 is preferably 5 μm or more and 50 μm or less, more preferably 9 μm or more and 35 μm or less, and even more preferably 12 μm or more and 25 μm or less.
By setting the thickness of the base material layer 2 to the lower limit value or more, the rigidity of the release film 11 is increased, and excessive deformation and wrinkles can be easily suppressed. As a result, mold followability and dimensional stability can be obtained. On the other hand, by setting the thickness of the base material layer 2 to the above upper limit value or less, the rigidity of the release film 11 can be controlled, and a good balance between mold followability and mold releasability can be achieved.

Materials for the substrate layer 2 include one or more selected from poly-4-methyl-1-pentene resins, polyester resins, polyamide resins, and polyolefin resins.
Examples of the polyester resin, the polyamide resin, and the polyolefin resin are the same as those described for the release layer 1 above. Polypropylene resin is suitable as the polyolefin resin.

A stretched film may also be used as the substrate layer 2, and stretching can be performed using known methods such as sequential biaxial stretching, simultaneous biaxial stretching, tubular stretching, and the like.

[Manufacturing method of release film]
As a method for forming the release film 11, a known method such as a coextrusion method, an extrusion lamination method, a dry lamination method, or an inflation method can be used. The release layer 1 may be formed on the substrate layer 2 by coating the surface of the substrate layer 2 with the first resin composition prepared as a paste.
In the release film 11, for example, the release layer 1 and the base material layer 2 may be manufactured separately and then joined by a laminator or the like. Moreover, the release layer 1 and the base material layer 2 may be joined as they are, or may be joined via an adhesive layer.
The method for manufacturing the substrate layer 2 is not limited, and specific examples include an inflation extrusion method, a T-die extrusion method, and the like.

[Application and usage of release film]
The release film 11 of the present embodiment is used to be placed between a mold to which a sealing resin is supplied and a semiconductor device to be resin-sealed in a process of resin-sealing a semiconductor device. That is, it may be a so-called release film for molding, or may be used for other purposes. As another application, for example, a cover lay film (hereinafter also referred to as "CL film") is adhered to a flexible film having an exposed circuit (hereinafter also referred to as "circuit exposed film") via an adhesive by hot pressing to form a flexible film. It is used for placement between a cover film and a mold when manufacturing a printed circuit board (hereinafter also referred to as "FPC"). In addition, for example, a release film for curing thermosetting resin prepreg such as CFRP, a release film for thermosetting resin molding, and a decorative transfer release film for printing on a product having a three-dimensional shape. etc. can also be used.

An example of a method for manufacturing a resin-encapsulated semiconductor device using the release film 11 will be described below.

A method for manufacturing a resin-encapsulated semiconductor device includes the following steps.
(Step 1) Semiconductor device preparation step (Step 2) Release film installation step (Step 3) Sealing resin supply step (Step 4) Curing step (Step 5) Mold demolding step I will explain the details.

(Step 1) Semiconductor Device Preparing Step A 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. An LED chip (light emitting diode) is exemplified as the light emitting element, and an image sensor is exemplified as the light receiving element.
Moreover, the support is a substrate formed in an arbitrary shape such as a circular shape or a polygonal shape. Examples of the support include ceramic substrates, silicone substrates, metal substrates, rigid substrates such as epoxy resin and BT resin, and flexible substrates such as polyimide resin and polyethylene substrates.

(Step 2) Release Film Installation Step The release film 11 is placed in a lower mold having a cavity recess for supplying the sealing resin. At this time, the release surface 3 of the release film 11 is placed on the front side, that is, in contact with the sealing resin to be supplied later.
Also, the release film 11 is arranged along the surface of the flat portion surrounding the cavity recess of the lower mold and the cavity recess. At this time, the planar portion surrounding the cavity recess is provided with a suction port for causing the release film 11 to follow the shape of the cavity recess of the lower mold. Air, water, gas, etc. in the space between the release film 11 and the mold are sucked and discharged from the suction port using a suction device or the like, and are vacuum-sucked. Furthermore, in order to firmly fix the release film 11 to the mold, a chuck is arranged at a position corresponding to the outer periphery of the sealing resin injection region, the outer periphery of the entire release film 11, or the outer periphery of the entire mold. The release film 11 may be sandwiched by a mechanism.
Examples of molds include known molds and resin molds.

(Step 3) Step of Supplying Sealing Resin Next, the sealing resin is supplied to the concave portion of the mold where the release film 11 is arranged. A known method can be used as a supply method. As the sealing resin, known resins can be used. as well as precursors thereof.
In the present embodiment, when the release film 11 is applied to the compression molding method (compression molding method), the shape of the sealing resin is processed into a tablet shape, a granular shape, a sealing granule shape, or a sheet shape. is preferred.
In the mold, the sealing resin is heated to a predetermined temperature and is in a fluid state.

(Step 4) Curing step Next, a semiconductor device to be molded is placed in an upper mold provided with a protruding fixture for holding the outer edge of the molding object so that the molding object does not drop. After mounting, the surface of the semiconductor device on which the semiconductor element is provided faces the lower mold, and is pressed against the mold in which the sealing resin is supplied to the concave portion. At this time, the fixture of the upper mold fits into the groove of the lower mold, and the semiconductor element is covered with the sealing resin. Subsequently, the encapsulating resin is cured by heating and pressurizing to obtain a molded body.
In addition, when the sealing resin is a precursor of a curable resin, it may be cured by heating and active energy ray irradiation. Examples of the active energy rays include radiation, ultraviolet rays, visible rays, and electron beams.

(Step 5) Demolding Step of Molded Body After that, the molded body is removed from the mold. In the demolding step of the molded article, air, water, gas, etc. are supplied between the mold release film 11 and the mold, whereby the mold release film 11 is peeled off from the mold and the molded article is demolded. At the same time or after this, the release film 11 is released from the molding.
When the number of semiconductor elements provided on the support is one, this molding becomes a resin-encapsulated semiconductor device.
Thereby, a semiconductor device having a good appearance can be obtained.

Although the embodiments of the present invention have been described above, these are examples of the present invention, and various configurations other than those described above can be adopted. Moreover, the present invention is not limited to the above-described embodiments, and includes modifications, improvements, etc. within the scope of achieving the object of the present invention.

EXAMPLES The present invention will be described in detail below with reference to Examples, but the present invention is not limited to the description of these Examples.

(1) Raw materials Raw material components used in the examples and comparative examples shown in Table 1 are shown below.
(Vinyl group-containing organopolysiloxane (A))
Low-vinyl group-containing linear organopolysiloxane (A1-1): a vinyl group-containing dimethylpolysiloxane synthesized according to Synthesis Scheme 1 (structure represented by formula (1-1) where only R ¹ (terminal) is a vinyl group structure that is
High-vinyl group-containing linear organopolysiloxane (A1-2): a vinyl group-containing dimethylpolysiloxane synthesized according to Synthesis Scheme 2 (a structure represented by formula (1-1) in which R ¹ and R ² are vinyl groups; some structure)

(Organohydrogenpolysiloxane (B))
・Made by Momentive: “TC-25D”

(Inorganic filler)
・ Inorganic filler (C): silica fine particles (particle size: 7 nm, specific surface area: 300 m ² /g), manufactured by Nippon Aerosil Co., Ltd., "AEROSIL 300"

(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)"

(Platinum or platinum compound (E))
・Made by Momentive: “TC-25A”

(Synthesis of vinyl group-containing organopolysiloxane (A))
[Synthesis Scheme 1: Synthesis of Low Vinyl Group-Containing Linear Organopolysiloxane (A1-1)]
A low-vinyl group-containing linear organopolysiloxane (A1-1) was synthesized according to the following formula (5).
That is, 74.7 g (252 mmol) of octamethylcyclotetrasiloxane and 0.1 g of potassium siliconate were placed in a 300 mL separable flask having a cooling tube and a stirring blade, which was replaced with Ar gas, and the temperature was raised to 120° C. for 30 minutes. Stirred. At this time, an increase in viscosity was confirmed.
After that, the temperature was raised to 155° C. and stirring was continued for 3 hours. After 3 hours, 0.1 g (0.6 mmol) of 1,3-divinyltetramethyldisiloxane was added, and the mixture was further stirred at 155° C. for 4 hours.
Furthermore, after 4 hours, it was diluted with 250 mL of toluene and then washed with water three times. The washed organic layer was washed several times with 1.5 L of methanol for reprecipitation purification to separate the oligomer and polymer. The obtained polymer was dried under reduced pressure at 60° C. overnight to obtain a low-vinyl group-containing linear organopolysiloxane (A1-1) (Mn=2.2×10 ⁵ , Mw=4.8×10 ⁵ ). Also, the vinyl group content calculated by H-NMR spectrum measurement was 0.04 mol %.

[Synthesis Scheme 2: Synthesis of High Vinyl Group-Containing Linear Organopolysiloxane (A1-2)]
In the above synthesis step (A1-1), in addition to 74.7 g (252 mmol) of octamethylcyclotetrasiloxane, 0.5 g of 2,4,6,8-tetramethyl 2,4,6,8-tetravinylcyclotetrasiloxane was added. Except for using 86 g (2.5 mmol), the same synthesis step as in (A1-1) was performed to obtain a high-vinyl group-containing linear organopolysiloxane (A1 -2) was synthesized. (Mn=2.3×10 ⁵ , Mw=5.0×10 ⁵ ). Also, the vinyl group content calculated by H-NMR spectrum measurement was 0.93 mol %.

(2) Preparation of first resin composition (preparation of release layer)
Each first resin composition was prepared as follows.
First, a mixture of 90% vinyl group-containing organopolysiloxane (A), a silane coupling agent and water (F) is kneaded in advance in the proportions shown in Table 1 below, and then an inorganic filler is added to the mixture. The mixture was further kneaded to obtain a kneaded product (silicone rubber compound).
Here, the kneading after adding the inorganic filler includes the first step of kneading for 1 hour at 60 to 90° C. under a nitrogen atmosphere for the coupling reaction, and the removal of the by-product (ammonia). A second step of kneading for 2 hours under a reduced pressure atmosphere at 160 to 180 ° C., then cooling, and the remaining 10% of the vinyl group-containing organopolysiloxane (A) is divided into two times. Add and knead for 20 minutes.
Subsequently, organohydrogenpolysiloxane (B) (TC-25D) and platinum or platinum compound (E) (TC -25A) was added and kneaded with a roll to obtain each first resin composition.

(3) Preparation of release film with base layer <Example 1>
As shown in Table 2, a biaxially oriented polybutylene terephthalate (OPBT1: manufactured by Toyobo Co., Ltd., Toyobo Ester (registered trademark) film, DE048) with a thickness of 15 μm was used as a base layer, and prepared in (2) above on the base layer. A paste composed of the first resin composition (solid content: 25% by mass, solvent decane) is applied using a bar coater, cured at 180 ° C. for 120 minutes, and a release layer is provided on the base layer. got the film. The thickness of the release layer of the obtained release film was 35 μm, and the surface roughness Rz of the release surface of the release layer was 0.1 μm.

<Example 2>
As shown in Table 2, in the same manner as in Example 1, except that the surface of the release layer was unevenly processed by inserting a matte film in the film forming process using the paste made of the first resin composition. A release film was prepared.

<Example 3>
As shown in Table 2, a release film was produced in the same manner as in Example 1, except that the thickness of the release layer was changed to 10 µm.

<Example 4>
As shown in Table 2, a release film was produced in the same manner as in Example 1, except that the thickness of the release layer was changed to 70 μm.

<Example 5>
As shown in Table 2, a release film was produced in the same manner as in Example 1, except that the first resin composition used for forming the release layer was changed to the composition shown in Table 2.

<Example 6>
As shown in Table 2, Example 1 except that the base material layer was changed to a biaxially oriented polybutylene terephthalate (OPET2: Boblet ST20 manufactured by Kojin Film & Chemicals Co., Ltd.) with a thickness of 20 μm and the thickness of the release layer was changed to 30 μm. A release film was prepared in the same manner as above.

<Example 7>
As shown in Table 2, Example 1 except that the base material layer was biaxially oriented polyethylene terephthalate (OPET1: manufactured by Toyobo Co., Ltd., Toyobo Ester (registered trademark) film) with a thickness of 9 μm and the thickness of the release layer was changed to 41 μm. A release film was prepared in the same manner as above.

<Example 8>
As shown in Table 2, the substrate layer was biaxially oriented polyethylene terephthalate (Toyobo Co., Ltd., Toyobo Ester (registered trademark) film) 12 μm thick, except that the thickness of the release layer was changed to 38 μm. A release film was prepared in the same manner.

<Example 9>
As shown in Table 2, the substrate layer was biaxially oriented polyethylene terephthalate (OPET2: manufactured by Toyobo Film Solution Co., Ltd., Teflex (registered trademark) film FW2) with a thickness of 13 μm, and the thickness of the release layer was changed to 37 μm. A release film was prepared in the same manner as in Example 1.

<Comparative Example 1>
As shown in Table 2, a release film was produced in the same manner as in Example 1, except that the first resin composition used for forming the release layer was changed to the composition shown in Table 2.

<Comparative Example 2>
As shown in Table 2, Example 1 except that the base material layer was biaxially oriented polyethylene terephthalate (OPET1: manufactured by Toyobo Co., Ltd., Toyobo Ester (registered trademark) film) with a thickness of 19 μm and the thickness of the release layer was changed to 31 μm. A release film was prepared in the same manner as above.

<Comparative Example 3>
As shown in Table 2, the procedure was the same as in Example 1, except that the base layer was changed to a film (35 μm thick) made using poly 4-methyl 1-pentene resin (manufactured by Mitsui Chemicals, TPX RT31). A release film was prepared by

<Comparative Example 4>
As shown in Table 2, the substrate layer was a film (25 μm thick) made using a polybutylene terephthalate elastomer resin (manufactured by DuPont Toray, Hytrel 6347), and the thickness of the release layer was changed to 25 μm. A release film was prepared in the same manner as in Example 1.

(4) Measurement/Evaluation Using the obtained release film, the following measurement/evaluation was performed. Table 2 shows the results.

(a) to (d); dynamic viscoelasticity (DMA) was measured using a DMA7100 (manufactured by Hitachi High-Tech Science) at a temperature increase rate of 5°C/min and a frequency of 1 Hz. From the viscoelastic spectrum, the storage modulus at 150°C, the storage modulus E'1 [MPa] at 25°C, the storage modulus E'2 [MPa] at 100°C, and the equilibrium modulus were obtained. Also, the obtained E'1 and E'2 were applied to the following equations.
(E'1-E'2) [MPa]/(100-25) [°C]
Further, the loss elastic modulus/storage elastic modulus (loss tangent) in the MD direction at 180° C. of the release film was determined.
Dynamic viscoelasticity (DMA) was measured using a dynamic viscoelasticity measuring device (manufactured by Hitachi High-Tech Science, "DMA7100") under the following measurement conditions.
(Measurement condition)
・Frequency: 1Hz
・Temperature range: 20 to 250°C
・Temperature increase rate: 5°C/min
・Test piece: 4 mm width x 20 mm
・Test mode: Tensile

(e) The 180° C. 5% tensile strength (5% modulus) of the release film was calculated from the SS curve obtained by measuring according to tensile test JIS-K7127.

(i) Measurement of surface roughness Rz of release surface of release film Measured in accordance with JIS B0601:2013.

(ii) Evaluation of Appearance of Molded Body First, the following granular thermosetting resin composition was prepared as a sealing resin.
(material)
・ Epoxy resin 1: biphenyl aralkyl type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., NC-3000)
・ Epoxy resin 2: biphenyl type epoxy resin (YL6677 manufactured by Mitsubishi Chemical Corporation)
・ Curing agent 1: biphenylene skeleton-containing phenol aralkyl resin (manufactured by Nippon Kayaku Co., Ltd., GPH-65)
Curing agent 2: Triphenylmethane type phenolic resin modified with formaldehyde (HE910-20, manufactured by Air Water)
・ Curing accelerator: triphenylphosphine (manufactured by Hokko Chemical Industry Co., Ltd., TPP)
・ Inorganic filler: fused spherical silica (FB-950FC manufactured by Denki Kagaku Kogyo Co., Ltd.)
・ Coloring agent: carbon black (Mitsubishi Chemical Co., Ltd., MA-600)
Coupling agent: N-phenyl-γ-aminopropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBM-573)
・Releasing agent: Carnauba wax (Nikko Carnauba manufactured by Nikko Fine Co., Ltd.)
(procedure)
4.5 parts by mass of the epoxy resin 1 described above, 4.5 parts by mass of the epoxy resin 2, 2.8 parts by mass of the curing agent 1, 2.8 parts by mass of the curing agent 2, and 0.4 parts by mass of the curing accelerator 84.2 parts by mass of an inorganic filler, 0.2 parts by mass of a coloring agent, 0.4 parts by mass of a coupling agent, and 0.2 parts by mass of a release agent were prepared. Next, after mixing each raw material component at room temperature using a mixer, the mixture was roll kneaded while being heated with two rolls at 45° C. and 90° C. to obtain a kneaded product. Next, after cooling the kneaded product, it was pulverized to obtain a granular thermosetting resin composition.

Next, using each release film, the thermosetting resin composition was cured (resin encapsulation) in the following procedure.
First, on an organic substrate having a thickness of 0.4 mm, a width of 65 mm, and a length of 190 mm, five semiconductor elements having a thickness of 0.3 mm and 7.5 mm square were adhered with a silver paste, followed by a gold wire having a diameter of 18 μm and a length of 7 mm. The wires were bonded with a pitch spacing of 60 μm. Next, the mold temperature of a compression molding machine (PMC1040, manufactured by TOWA Co., Ltd.) was set to 175°C in advance. Next, the organic substrate was fixed to the upper mold such that the surface on which the semiconductor element was mounted faced the lower mold. Next, after placing the release film prepared in each example and comparative example on the lower mold, the release film was made to conform to the mold by evacuating the internal space of the mold. Thereafter, a granular thermosetting resin composition (sealing resin composition) prepared on the release film was uniformly supplied. Next, immediately after supplying the encapsulating resin composition, the mold is clamped until the distance between the organic substrate and the release film is 4 mm, and at the same time, the cavity formed by the lower mold and the upper mold is filled 4 times. After reducing the pressure to a degree of pressure reduction of 0.8 Torr in seconds, the mold was completely clamped in 12 seconds while the pressure reduction was continued, and sealing molding was performed under the conditions of a molding pressure of 3.9 MPa and a curing time of 90 seconds.

(iii) Evaluation of release film [mold followability]
In the above procedure, the degree of air pockets between the mold and the release film when the mold release film was caused to follow the mold by vacuuming was evaluated according to the following criteria.
◎: No air pools ○: Small air pools present, but no practical problem (or non-evaluable)

[Dimensional stability]
In the above procedure, the appearance of the cured product (wrinkles, etc.) after releasing the cured product from the release film after molding was evaluated according to the following criteria.
○: No wrinkles or deformation, no problem △: Some wrinkles, but no practical problem ×: Large wrinkles, molding defects occurred

[Releasability]
In the above procedure, the release behavior when the cured product was released from the molded release film and the state of the cured product (displacement, deflection, etc.) were evaluated according to the following criteria.
○: No problem with mold release and molded product △: Molded product shifts and warps when demolded, but no practical problem ×: Unable to release, or large shift or warp in molded product

[Interlayer strength]
In the above procedure, the state of the release layer when the cured product was released from the release film after molding was evaluated according to the following criteria.
◯: No peeling of the release layer, no problem △: Part of the release layer lifted from the substrate layer, but no practical problem ×: The release layer was largely peeled off from the substrate layer

1 release layer 2 base layer 3 release surface 11 release film

Claims (6)

A release film having a viscoelastic spectrum measured at a temperature elevation rate of 5°C/min and a frequency of 1 Hz in dynamic viscoelasticity (DMA) measurement that satisfies the following (a) and (b).
(a) a storage modulus at 150° C. of 50 MPa or more;
(b) When the storage modulus at 25° C. is E′1 [MPa] and the storage modulus at 100° C. is E′2 [MPa], (E′1−E′2) [MPa]/(100− 25) [°C] is 5 to 60; A release film having a viscoelastic spectrum measured at a temperature increase rate of 5°C/min and a frequency of 1 Hz in dynamic viscoelasticity (DMA) measurement that satisfies the following (c).
(c) It has an equilibrium elastic modulus at least in the range of 200° C. or higher and 250° C. or lower, and the equilibrium elastic modulus is 1 MPa or more. The release film according to claim 1 or 2, wherein the viscoelastic spectrum measured under the conditions of a temperature increase rate of 5°C/min and a frequency of 1 Hz in dynamic viscoelasticity (DMA) measurement satisfies the following condition (d): .
(d) Loss modulus/storage modulus (loss tangent) at 180° C. in the MD direction is 0.05 or more and 0.2 or less. The release film according to any one of claims 1 to 3, which satisfies the following condition (e).
(e) The release film has a 180° C. 5% tensile strength (5% modulus) of 1 MPa or more and 5 MPa or less. Any one of claims 1 to 4, wherein the release film has a multilayer structure including a release layer that forms at least one surface of the release film and a substrate layer made of a material different from the release layer. or the release film according to item 1. 6. Any one of claims 1 to 5, wherein the release film is provided between a mold and the semiconductor device in a resin-encapsulating resin molding process for resin-sealing the semiconductor device. 1. The release film according to item 1.

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