WO2023047977A1

WO2023047977A1 - Mold release film for processing, method for producing same, and use of same

Info

Publication number: WO2023047977A1
Application number: PCT/JP2022/033851
Authority: WO
Inventors: 直紀吉田
Original assignee: 三井化学東セロ株式会社
Priority date: 2021-09-21
Filing date: 2022-09-09
Publication date: 2023-03-30
Also published as: JPWO2023047977A1; CN117957105A; TW202321039A; KR20240042018A

Abstract

The present invention provides a mold release film for processing, which enables the production of a resin-sealed semiconductor or the like with a high productivity that exceeds the limits of the prior art by having high deaeration properties, while maintaining properties such as excellent mold releasability, excellent appearance of molded articles and excellent followability to a mold, these properties having been required for mold release films for processing in the past, and achieving a good balance among these properties at high levels that exceed the limits of the prior art. The above are achieved by means of a mold release film for processing, which is provided with recesses and projections on at least one of two surfaces, wherein the developed interfacial area ratio (Sdr) of the surface that is provided with the recesses and projections is 4.0% to 50.0% as measured with a laser microscope.

Description

Release film for process, its manufacturing method, and use.

The present invention relates to a process release film, preferably a process release film used in a semiconductor encapsulation process or the like. The present invention relates to a process release film, a method for producing the same, and a method for producing a resin-sealed semiconductor using the same, which enables efficient production of resin-sealed semiconductors and the like.

In recent years, with the reduction in size and weight of semiconductor packages, etc., it is being considered to reduce the amount of sealing resin used. It is desired to reduce the amount of release agent contained in the sealing resin so that the interface between the semiconductor chip and the resin can be firmly adhered even if the amount of the sealing resin used is reduced. . For this reason, a method of disposing a release film between the inner surface of the mold and the semiconductor chip or the like has been adopted as a method of obtaining mold releasability between the sealing resin and the mold after curing and molding.

At the time of sealing, the release film is usually stretched along the inner surface of the mold by vacuum suction and brought into close contact with the inner surface. At this time, the release film adheres to the inner surface in a state in which the air is not completely released while being stretched, and an air pool is partially formed between the release film and the inner surface of the mold, and the release film is formed at that part. The film may wrinkle. If the release film has wrinkles, the shape of the wrinkles on the release film surface is transferred to the surface of the resin sealing portion, resulting in poor appearance and problems such as a decrease in yield. Suppression of wrinkles caused by this has been desired. In addition, if pinholes or the like occur in the release film at this time, the mold will be contaminated, so it has been necessary to effectively suppress pinholes and the like.
In order to solve such problems, it has been proposed to provide unevenness that satisfies specific conditions on the release film surface. More specifically, for example, a release film having a specific surface roughness (Rz) ( For example, see Patent Document 1), a release film having a specific arithmetic mean roughness (Ra) and a specific peak count (RPc) (see Patent Document 2, for example), and the like have been proposed.

JP-A-2002-359259 International Publication No. 2015/068808 A1 pamphlet

However, with the development of this technical field, the level of demand for release films for processes such as release films for semiconductor encapsulation processes is increasing year by year. A high degassing property that can complete the air evacuation in a shorter time has come to be demanded.
The present invention has been made in view of such circumstances. A process release film that maintains the excellent release properties, appearance of molded products, mold followability, etc., which are required for release films, and balances these at a high level that exceeds the limits of conventional technology. intended to provide

As a result of intensive studies by the present inventors in order to solve the above problems, it is found that setting the Sdr (spreading interface area ratio) of the surface of the release film for processing to an appropriate value is the release film for processing. have found that it is important for achieving high degassing properties without impairing the properties of the above, and have completed the present invention.
That is, the present invention and its respective embodiments are as described in [1] to [9] below.

[1]
A process in which unevenness is formed on at least one of the two surfaces, and the surface on which the unevenness is formed has an Sdr (development interface area ratio) measured with a laser microscope of 4.0 to 50.0%. release film.
[2]
The process release film according to [1], wherein the RPc (peak count) of the surface on which the unevenness is formed and the Sdr (development interface area ratio) is 4.0 to 50.0% is 30 to 87. .
[3]
[1] or [2], wherein the water contact angle of the surface opposite to the surface on which the unevenness is formed and the Sdr (spread interface area ratio) is 4.0 to 50.0% is 90 to 130° ] The release film for the process described in .
[4]
The process release film according to any one of [1] to [3], which has a thickness of 10 to 100 μm.
[5]
The process release film according to any one of [1] to [4], which has a tensile elastic modulus of 30 to 500 MPa at 120°C.
[6]
The process release film according to any one of [1] to [5], which has a tensile elastic modulus of 20 to 400 MPa at 170°C.
[7]
A step of blasting the surface of the metal roll with particles having a particle size of 40 to 100 mesh to produce a metal embossing roll, and passing the film between the metal embossing roll and another roll forming irregularities on the surface of the film;
The method for producing a process release film according to any one of [1] to [6].
[8]
The process release film according to any one of [1] to [6], which is used in a semiconductor encapsulation step.
[9]
A method for manufacturing a resin-encapsulated semiconductor,
A step of placing a semiconductor device to be resin-sealed at a predetermined position in a molding die;
The release film for process according to any one of [1] to [6] is applied to the inner surface of the molding die so that the unevenness is formed and the Sdr (development interface area ratio) is 4.0 to 50.0. a step of arranging the surface with 0% so as to face the inner surface of the molding die;
deaeration between the process release film and the inner surface of the mold;
A step of curing the encapsulating resin disposed between the semiconductor device and the release film for semiconductor encapsulation process after clamping the molding die;
A method for manufacturing the resin-encapsulated semiconductor.

The process release film of the present invention has high degassing properties, can complete air removal between the release film and the inner surface of the mold in a short time, and has excellent releasability, suppression of wrinkles, and metal mold. Since it also has mold followability, by using this, it is possible to manufacture molded articles obtained by resin-sealing semiconductor chips and the like with high productivity and quality beyond the limits of conventional technology.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows an example of the manufacturing method of the resin-sealed semiconductor using the release film for processes of this invention.

In the present invention, unevenness is formed on at least one of the two surfaces, and the surface on which the unevenness is formed has an Sdr (development interface area ratio) of 4.0 to 50.0% measured with a laser microscope. It is a process release film.
In the mold release film for processing of the present invention, unevenness is formed on at least one surface thereof, and the Sdr (development interface area ratio) of the uneven surface is within a predetermined numerical range. Realizing high degassability, for example, when used as a process release film in a molding process using a mold, it is possible to complete the removal of air between the process release film and the inner surface of the mold in a short time. It can contribute to the improvement of the productivity of the molding process.

In the mold release film for processing of the present invention, it is sufficient that at least one of the two surfaces has unevenness. That is, only one surface may have unevenness. may be formed.
In many usage forms of release films for processes, the degassing property of one surface located on the side of the mold is important, so it is sufficient if one surface has unevenness. Forming unevenness only on the surface is advantageous in terms of ease of manufacture, cost, and the like. In some cases, smoothness is required on the surface of a resin such as a sealing resin, and from this point of view, a release film having unevenness formed only on one surface is preferably used in some cases.
Forming unevenness on both surfaces is advantageous in that both surfaces can be provided with excellent degassing properties and releasability. , traces of resin flow, etc. can be made difficult to understand.

There are no particular restrictions on the shape of the unevenness, and for example, it may be formed into various shapes such as pear-skin, hairline, grid, round, square, star-shaped, and the like. When forming unevenness using a metal embossing roll manufactured by blasting using particles with a particle size of 40 to 100 mesh, which will be described later, the shape should be a satin finish or the like from the viewpoint of ease of production. is preferred.

When unevenness is formed on both surfaces, only the unevenness on one surface may satisfy the condition that Sdr is 4.0 to 50.0%, and the unevenness on both surfaces may satisfy the condition that Sdr is 4.0 to 50.0%. It may satisfy the condition of 4.0 to 50.0%. As described above, in many usage forms, the degassing property of one surface located on the mold side is important, so in that case, only the unevenness on one surface has an Sdr of 4.0 to 50.0%. It suffices if the condition that
In the case of imparting excellent air-removing properties to both surfaces depending on the mode of use, it is preferable that the unevenness on both surfaces satisfies the condition that the Sdr is 4.0 to 50.0%.

The developed interface area ratio (Sdr) of the uneven surface indicates how much the actual surface area increases with respect to the area of the defined region.
More specifically, the developed area ratio Sdr is defined by the following formula, Sdr is 0 on a perfect plane, and Sdr is 0.414 (41.4%) on a 45° inclined plane. .

(Wherein, x and y are the ordinate and abscissa of the defined area, z is the height at that coordinate, and A is the area of the defined area.)
Sdr can be measured by a method conventionally known in the art, and more specifically, it can be measured and analyzed using a laser microscope and accompanying software. For example, it can be measured by the method described in Examples in the present specification.

Although the mechanism by which the effects of the present invention, such as high degassing in the lateral direction, are obtained when Sdr is within the above range, it is not necessarily clear that the uneven state of the surface specified by Sdr is within a predetermined range. Therefore, it is presumed that there is some relationship with the fact that a sufficient air flow path can be secured between the mold and the like.
Sdr is preferably 6% or more, particularly preferably 8% or more, from the viewpoint of achieving even better degassing properties.
A higher Sdr is preferable from the viewpoint of degassability, and there is no particular upper limit from the relationship with the object of the present invention. is common, and 30% or less is more common.
The Sdr can be appropriately adjusted by adjusting the conditions for manufacturing the release film for processing and the state of the surface by surface treatment or the like. More specifically, for example, the surface of the metal roll described later is blasted with particles having a particle size of 40 to 100 mesh, and the particle size in the process of manufacturing the metal embossing roll. By setting the temperature of the embossing roll in the step of passing the film between a metal embossing roll and another roll to form irregularities on the film surface, etc., to suitable values, it is possible to make appropriate adjustments.

In the release film of the present invention, the RPc (peak count) of at least one of the uneven surfaces is preferably 30-87. When the RPc of the uneven surface is within a predetermined numerical range, a higher degassing property in the lateral direction is realized, and for example, when used as a release film for a process in a molding process using a mold, the process It can contribute to further improvement of the productivity of the molding process, such as completing the removal of air between the release film and the inner surface of the mold in a shorter time.
In this embodiment, when unevenness is formed on both surfaces, only one of the surfaces may satisfy the condition that the RPc (peak count) is 30 to 87. The unevenness may satisfy the condition that the RPc (peak count) is 30-87.
The surface having an RPc (peak count) of 30 to 87 in the present embodiment is preferably the same surface as the surface having an Sdr (ratio of developed interface area) of 4.0 to 50.0%.

RPc (peak count) in the present invention is a peak count number based on a roughness curve measured based on JIS B0601 2013 (ISO4287:1997, Amd.1:2009), and is defined by the following formula (I). be.
RPc=L/RSm (I)
In formula (I), L indicates a reference length of 10 mm.
RSm indicates the average length of roughness curve elements and is measured based on JIS B0601:2013 (ISO4287:1997, Amd.1:2009).
The measurement can be performed using a surface roughness measuring instrument, more specifically, for example, by the method described in Examples of the present application.

Although the mechanism by which higher lateral degassability is realized by RPc being within the above range is not necessarily clear, when the peak density specified by RPc is within a predetermined range, the air flow path It is presumed that there is some relationship with the fact that the number and size of are more appropriate, and that this, coupled with the above-mentioned specific Sdr, ensures a sufficient flow path for air between the mold and the like. are doing.
RPc is preferably 40 to 80, particularly preferably 50 to 80, from the viewpoint of achieving even better degassing properties.
RPc can be appropriately adjusted by adjusting the conditions for manufacturing the release film for the process and the state of the surface by the surface treatment described later. More specifically, for example, the surface of the metal roll described later is blasted with particles having a particle size of 40 to 100 mesh, and the particle size in the process of manufacturing the metal embossing roll. By setting the temperature of the embossing roll in the step of passing the film between a metal embossing roll and another roll to form irregularities on the film surface, etc., to suitable values, it is possible to make appropriate adjustments.

In the process release film of the present invention, it is preferable that the surface opposite to the surface on which unevenness having Sdr of 4.0 to 50% is formed has a water contact angle of 90 to 130°. When the water contact angle of the surface is within the above numerical range, it is possible to achieve even better releasability between the process release film of the present embodiment and the object to be molded.
In the process release film of the present embodiment, only one surface, that is, the surface opposite to the uneven surface having Sdr of 4.0 to 50%, has a water contact angle of 90 to 130°. and the water contact angles on both surfaces may be in the range of 90 to 130°. For example, when used in a molding process using a mold, from the viewpoint of improving both the releasability from the mold and the releasability from the molded object, both surfaces should have a water contact angle of 90 to 90. It is preferably in the range of 130°.

The water contact angle of the film surface in the present embodiment can be measured using a contact angle measuring instrument in accordance with JIS R3257, and more specifically, for example, by the method described in the Examples of the present application. can be done.
The water contact angle of the release film surface is more preferably 95° to 120°, still more preferably 98° to 115°, and particularly preferably 100° to 110°.

The water contact angle on the surface of the release film can be appropriately increased or decreased by means conventionally used in the industry. can be within From this point of view, the surface of the process release film of the present invention preferably contains a resin selected from the group consisting of fluororesin, 4-methyl-1-pentene (co)polymer, and polystyrene resin. In addition, an additive (mold release agent) capable of improving releasability may be used, or surface treatment may be performed.
There are no particular restrictions on the types of release agents that can be used, and silicone-based release agents, melamine-based release agents, polyolefin-based release agents, epoxy-based release agents, acrylic-based release agents, and fluorine-based release agents. , cellulose-based release agents, paraffin-based release agents, epoxy-melamine-based release agents, long-chain alkyl-based release agents, and combinations thereof. In particular, it is preferable to use fluorine-based release agents, long-chain alkyl-based release agents, and the like.
These release agents may be added to the resin forming the surface of the release film for processing, or may be applied to the surface of the release film for processing.
The water contact angle can also be appropriately adjusted by adjusting the shape, density, size, etc. of the unevenness formed on the surface of the film in the present invention.

The total thickness of the process release film of the present invention is not particularly limited, and an appropriate thickness may be selected according to the application and usage of the process release film. It is preferably 30 to 150 μm, more preferably 30 to 150 μm.
When the total thickness of the release film is in the above range, it is preferable because the handling property when used as a roll is good and the amount of waste of the release film is small.
The thickness of the process release film of the present invention can be appropriately adjusted by adjusting the film production conditions. For example, when the film is produced by extrusion molding, the lip interval at that time is adjusted. When the film is stretched, it can be adjusted by appropriately setting the stretch ratio.

From the viewpoint of suppressing wrinkles during molding, etc., the process release film of the present invention preferably exhibits a specific tensile modulus.
That is, the process release film of the present invention preferably has a tensile elastic modulus at 120°C of 30 MPa to 500 MPa, or preferably has a tensile elastic modulus at 170°C of 20 MPa to 400 MPa. Further, the process release film of the present invention preferably has a tensile modulus at 120°C of 30 MPa to 500 MPa and a tensile modulus at 170°C of 20 MPa to 400 MPa.
When the laminated film has a tensile modulus of elasticity of 30 MPa to 500 MPa at 120° C. or a modulus of elasticity in tension of 20 MPa to 400 MPa at 170° C., for example, wrinkles occur when used in a resin sealing process or the like. can be suppressed more effectively.
The mechanism by which the occurrence of wrinkles is suppressed by exhibiting the above-mentioned specific value for the tensile modulus of elasticity of the process release film at a specific temperature is not necessarily clear. It is presumed that having an elastic modulus suppresses deformation leading to the generation of wrinkles, and that having a tensile elastic modulus of a certain value or less disperses strain.
From the standpoint of mold followability, the tensile modulus at 120°C is preferably 300 MPa or less, and more preferably 200 MPa or less at 170°C.

The process release film of the present embodiment preferably has a tensile modulus at 120° C. of 30 MPa to 500 MPa,
more preferably 40 MPa to 450 MPa,
more preferably from 50 MPa to 400 MPa,
It is more preferably 200 MPa to 350 MPa,
250 MPa to 300 MPa is particularly preferred.
The process release film of the present embodiment preferably has a tensile modulus at 170° C. of 20 MPa to 400 MPa,
more preferably from 25 MPa to 300 MPa,
It is more preferably 30 MPa to 250 MPa, further preferably 100 MPa to 200 MPa,
120 MPa to 160 MPa is particularly preferred.
In the laminated film constituting the process release film of the present invention, both the tensile elastic modulus at 120°C and the tensile elastic modulus at 170°C are within the above preferred ranges. It is particularly preferred because of its wide range of applications.

The tensile modulus of the process release film of the present embodiment can be measured at 120° C. or 170° C. using a tensile tester in accordance with JIS K7127. It can be measured by the method described in .
There is no particular limitation on the method for adjusting the tensile modulus of the process release film, and it may be adjusted as appropriate by a method conventionally employed in the industry. It can be adjusted by selection. More specifically, for example, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyamide-6, polyamide-66, polypropylene, ethylene-tetrafluoroethylene copolymer, syndiotactic polystyrene, 4-methylpentene-1 By appropriately using a polymeric material such as a (co)polymer having relatively excellent heat resistance, it becomes easy to achieve the above tensile elastic modulus.
In addition, stretching (uniaxial stretching or biaxial stretching) of the film generally improves the tensile modulus of the process release film, and this can be used to appropriately adjust the tensile modulus.

The process release film of the present invention may be a single layer film or a laminated film of two or more layers.
A single-layer film is preferable from the viewpoints of simplicity of construction and production, cost, and the like.
On the other hand, it simultaneously and efficiently achieves properties that the film surface should have or preferably has, such as surface properties and releasability, and properties that the entire film, such as tensile elasticity, preferably has. From the viewpoint, it is preferably a laminated film having two or more layers.
In particular, it is particularly preferable to be a laminated film including a release layer A having releasability from a molded product or a mold, and a heat-resistant resin layer B supporting the release layer.
Further, when it is desired that both surfaces have releasability, it may further include a release layer A′ and have a layer structure of release layer A/heat-resistant resin layer B/release layer A′. preferable.

Release layer A
The release layer A constituting the process release film of the present embodiment is a layer in contact with the mold surface when used in a molding process using a mold, and has degassing properties and peelability from the mold. From the viewpoint of smoothing the surface roughness, unevenness having an Sdr (expansion interface area ratio) of 4.0 to 50.0% is formed. The details of the unevenness and its preferred form are as described above.
The water contact angle of the release layer A is not particularly limited, but the contact angle with water is preferably 90° to 130°, more preferably 95° to 120°, from the viewpoint of further improving the releasability from the mold. , particularly preferably 98° to 115°, more preferably 100° to 110°. It is preferable to include a resin selected from the group consisting of fluororesins, 4-methyl-1-pentene (co)polymers, and polystyrene-based resins in view of the excellent releasability of molded articles and the ease of availability.

The fluororesin that can be used for the release layer A may be a resin containing structural units derived from tetrafluoroethylene. It may be a homopolymer of tetrafluoroethylene, or a copolymer with other olefins. Examples of other olefins include ethylene. A preferred example is a copolymer containing tetrafluoroethylene and ethylene as monomer structural units. The proportion of structural units derived from is preferably 0 to 45% by mass.

The 4-methyl-1-pentene (co)polymer that can be used in the release layer A may be a homopolymer of 4-methyl-1-pentene, and 4-methyl-1-pentene and Copolymers with other olefins having 2 to 20 carbon atoms (hereinafter referred to as "olefins having 2 to 20 carbon atoms") may also be used.

In the case of a copolymer of 4-methyl-1-pentene and an olefin having 2 to 20 carbon atoms, the olefin having 2 to 20 carbon atoms to be copolymerized with 4-methyl-1-pentene is 4-methyl -1-Pentene can impart flexibility. Examples of C2-C20 olefins include ethylene, propylene, 1-butene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-tetradecene, 1-hexadecene, 1-heptadecene, 1 -octadecene, 1-eicosene, and the like. These olefins may be used alone or in combination of two or more.

In the case of a copolymer of 4-methyl-1-pentene and an olefin having 2 to 20 carbon atoms, the ratio of structural units derived from 4-methyl-1-pentene is 96 to 99% by mass, and other The ratio of structural units derived from olefins having 2 to 20 carbon atoms is preferably 1 to 4% by mass. By reducing the content of structural units derived from olefins having 2 to 20 carbon atoms, the copolymer can be hardened, that is, the storage elastic modulus E' can be increased, and the occurrence of wrinkles in the sealing process etc. can be suppressed. It is advantageous to On the other hand, by increasing the content of structural units derived from olefins having 2 to 20 carbon atoms, the copolymer can be softened, that is, the storage elastic modulus E' can be lowered, and mold followability can be improved. It is advantageous to

The 4-methyl-1-pentene (co)polymer can be produced by a method known to those skilled in the art. For example, it can be produced by a method using known catalysts such as Ziegler-Natta catalysts and metallocene catalysts. The 4-methyl-1-pentene (co)polymer is preferably a highly crystalline (co)polymer. The crystalline copolymer may be either a copolymer having an isotactic structure or a copolymer having a syndiotactic structure. In particular, it should be a copolymer having an isotactic structure. is preferable from the viewpoint of physical properties and is easily available. Furthermore, the 4-methyl-1-pentene (co)polymer can be molded into a film, and if it has strength to withstand the temperature and pressure during mold molding, the stereoregularity and molecular weight are also limited. not. The 4-methyl-1-pentene copolymer may be a commercially available copolymer such as TPX (registered trademark) manufactured by Mitsui Chemicals, Inc.

Polystyrene-based resins that can be used for the release layer A include styrene homopolymers and copolymers, and the styrene-derived structural units contained in the polymer are at least 60% by weight or more. It is preferably 80% by weight or more, more preferably 80% by weight or more.
The polystyrene-based resin may be either isotactic polystyrene or syndiotactic polystyrene, but isotactic polystyrene is preferable from the viewpoint of transparency, availability, etc., and mold releasability, heat resistance, etc. From the viewpoint of, syndiotactic polystyrene is preferable. One type of polystyrene may be used alone, or two or more types may be used in combination.

The release layer A preferably has heat resistance that can withstand the temperature of the mold during molding (typically 120 to 180°C). From this point of view, the release layer A preferably contains a crystalline resin having a crystalline component, and the melting point of the crystalline resin is preferably 190° C. or higher, more preferably 200° C. or higher and 300° C. or lower.
In order to bring crystallinity to the release layer A, for example, the fluorine resin preferably contains at least a structural unit derived from tetrafluoroethylene, and the 4-methyl-1-pentene (co)polymer contains 4-methyl-1 It preferably contains at least structural units derived from -pentene, and preferably contains at least syndiotactic polystyrene in polystyrene resins. Since the resin constituting the release layer A contains a crystalline component, wrinkles are less likely to occur in the resin sealing process, etc., and are suitable for suppressing the appearance defects caused by the transfer of wrinkles to the molded product. .

The resin containing the crystalline component that constitutes the release layer A has a crystal melting heat quantity of 15 J/g or more and 60 J/g or less in the first heating step measured by differential scanning calorimetry (DSC) according to JISK7221. and more preferably 20 J/g or more and 50 J/g or less. When it is 15 J/g or more, it is possible to more effectively exhibit heat resistance and releasability that can withstand hot press molding in a resin sealing process, etc., and also to suppress the dimensional change rate. Therefore, the occurrence of wrinkles can also be prevented. On the other hand, when the heat of crystal fusion is 60 J/g or less, the release layer A has an appropriate hardness, and sufficient followability of the film to the mold can be obtained in the resin sealing process or the like. Film breakage is effectively suppressed.

The release layer A may contain other resins in addition to the fluororesin, 4-methyl-1-pentene copolymer, and/or polystyrene resin. In this case, it is preferable that the hardness of the other resin is relatively high. Examples of other resins include polyamide-6, polyamide-66, polybutylene terephthalate, polyethylene terephthalate. Even when the release layer A contains, for example, a large amount of a soft resin (for example, a large amount of an olefin having 2 to 20 carbon atoms in a 4-methyl-1-pentene copolymer), the hardness is relatively low. By further including a high-grade resin, the release layer A can be hardened, which is advantageous in suppressing the occurrence of wrinkles in the encapsulation process or the like.

The content of these other resins is preferably, for example, 3 to 30% by mass based on the resin component constituting the release layer A. By setting the content of the other resin to 3% by mass or more, the effect of addition can be made substantial. be able to.

In addition to the fluororesin, 4-methyl-1-pentene (co)polymer, and/or polystyrene-based resin, the release layer A contains a heat stabilizer and a weather-resistant stabilizer within a range that does not impair the purpose of the present embodiment. Known additives generally blended in film resins, such as agents, rust inhibitors, anti-copper damage stabilizers, and antistatic agents, may also be included. The content of these additives can be, for example, 0.0001 to 10 parts by weight with respect to 100 parts by weight of the fluororesin, 4-methyl-1-pentene copolymer, and/or polystyrene resin.

The thickness of the release layer A is not particularly limited as long as it has sufficient releasability from the molded product, but it is usually 1 to 50 μm, preferably 5 to 30 μm.

Release layer A'
As described above, the process release film of the present embodiment may have a release layer A′ in addition to the release layer A and the heat-resistant resin layer B. That is, the process release film of the present embodiment may be a process release film that is a laminated film including a release layer A, a heat-resistant resin layer B, and a release layer A′ in this order. . In this case, the contact angle of the release layer A′ to water is preferably 90° to 130°, more preferably 95° to 120°, and particularly preferably 98° to 115°, more preferably 100° to 110°.
Details such as preferable materials of the release layer A′ are the same as those described above for the release layer A.
The surface of the release layer A′ may or may not have irregularities having an Sdr (development interface area ratio) of 4.0 to 50.0%. When required, it is preferable that the unevenness is not formed.
On the other hand, when both surfaces are required to have excellent degassing properties, unevenness may be formed.

When the process release film of the present embodiment is a laminated film containing the release layer A, the heat-resistant resin layer B, and the release layer A' in this order, the release layer A and the release layer A' may be layers of the same configuration, or may be layers of different configurations.
From the viewpoint of prevention of warping and ease of handling by having the same releasability on both sides, it is preferable that the release layer A and the release layer A' have the same or substantially the same configuration. Preferably, the release layer A and the release layer A' are optimally designed in relation to the process using them. From the viewpoint of making the layer A' excellent in releasability from the molding, it is preferable that the release layer A and the release layer A' have different structures.
When the release layer A and the release layer A' have different structures, the release layer A and the release layer A' may be made of the same material and have different structures such as thickness. However, the materials and other configurations may be different.

Heat-resistant resin layer B
The heat-resistant resin layer B that constitutes the process release film of the present embodiment supports the release layer A (and the release layer A′ in some cases) and has the function of suppressing the occurrence of wrinkles due to mold temperature and the like. .
Any resin layer including a non-stretched film can be used for the heat-resistant resin layer B, but it is particularly preferable to include a stretched film.

The stretched film may be a uniaxially stretched film or a biaxially stretched film. In the case of a uniaxially stretched film, it may be longitudinally stretched or transversely stretched, but it is desirable that the film is stretched at least in the transverse (TD) direction.
The method and apparatus for obtaining the stretched film are not particularly limited, and stretching may be performed by a method known in the art. For example, it can be stretched with a heating roll or a tenter-type stretching machine.

As the stretched film, it is preferable to use a stretched film selected from the group consisting of a stretched polyester film, a stretched polyamide film, and a stretched polypropylene film. These stretched films are relatively easy to reduce or make the coefficient of thermal expansion in the transverse (TD) direction negative by stretching, and have mechanical properties suitable for the application of the present embodiment, Moreover, it is particularly suitable as a stretched film in the heat-resistant resin layer B because it is inexpensive and relatively easily available.

As the stretched polyester film, a stretched polyethylene terephthalate (PET) film and a stretched polybutylene terephthalate (PBT) film are preferable, and a biaxially stretched polyethylene terephthalate (PET) film is particularly preferable.
Polyamide constituting the stretched polyamide film is not particularly limited, but polyamide-6, polyamide-66 and the like can be preferably used.
As the oriented polypropylene film, a uniaxially oriented polypropylene film, a biaxially oriented polypropylene film, or the like can be preferably used.
There is no particular limitation on the draw ratio, and an appropriate value may be appropriately set in order to appropriately control the thermal dimensional change rate and achieve suitable mechanical properties. , It is preferably in the range of 2.7 to 8.0 times in both the transverse direction, and in the case of a stretched polyamide film, it is preferably in the range of 2.7 to 5.0 times in both the longitudinal direction and the transverse direction. In the case of a polypropylene film, in the case of a biaxially oriented polypropylene film, it is preferably in the range of 5.0 to 10.0 times in both the machine direction and the transverse direction, and in the case of a uniaxially oriented polypropylene film, it is 1.0 times in the machine direction. A range of 5 to 10.0 times is preferable.

The heat-resistant resin layer B has heat resistance that can withstand the temperature of the mold during molding (typically 120 to 180 ° C.) from the viewpoint of controlling the strength of the film and its thermal dimensional change rate within an appropriate range. is preferred. From this point of view, the heat-resistant resin layer B preferably contains a crystalline resin having a crystalline component, and the melting point of the crystalline resin is preferably 125° C. or higher, and the melting point is 155° C. or higher and 300° C. or lower. is more preferably 185° C. or higher and 210° C. or lower, and particularly preferably 185° C. or higher and 205° C. or lower.

As described above, the heat-resistant resin layer B preferably contains a crystalline resin having a crystalline component. As the crystalline resin to be contained in the heat-resistant resin layer B, for example, a crystalline resin such as polyester resin, polyamide resin, or polypropylene resin can be used partially or wholly. Specifically, it is preferable to use polyethylene terephthalate or polybutylene terephthalate for the polyester resin, polyamide 6 or polyamide 66 for the polyamide resin, and isotactic polypropylene for the polypropylene resin.

By including the crystalline component of the crystalline resin in the heat-resistant resin layer B, wrinkles are less likely to occur in the resin sealing process, etc., and are more advantageous in suppressing appearance defects due to transfer of wrinkles to the molded product. Become.
The resin constituting the heat-resistant resin layer B preferably has a crystal melting heat quantity of 20 J/g or more and 100 J/g or less in the first heating step measured by differential scanning calorimetry (DSC) according to JISK7221. It is more preferably 25 J/g or more and 65 J/g or less, more preferably 25 J/g or more and 55 J/g or less, more preferably 28 J/g or more and 50 J/g or less, and 28 J/g or more. It is more preferably 28 J/g or more and 35 J/g or less, more preferably 28 J/g or more and 35 J/g or less. When it is 20 J/g or more, it is possible to effectively exhibit heat resistance and releasability that can withstand hot press molding in a resin encapsulation process or the like, and it is also possible to slightly suppress the dimensional change rate. , the occurrence of wrinkles can also be prevented. On the other hand, when the heat of crystal fusion is 100 J/g or less, the heat-resistant resin layer B can be given an appropriate degree of hardness. In addition to being able to prevent damage to the film, it is possible to effectively suppress damage to the film. In the present embodiment, the heat of crystal fusion is the amount of heat (J/g) on the vertical axis and the amount of heat (J/g) on the horizontal axis obtained in the first heating step in the measurement by differential scanning calorimetry (DSC) according to JISK7221. In a chart showing the relationship with temperature (°C), it refers to a numerical value obtained by summing peak areas having a peak at 120°C or higher.
The amount of heat of crystal fusion of the heat-resistant resin layer B can be adjusted by appropriately setting heating and cooling conditions during film production and stretching conditions.

The thickness of the heat-resistant resin layer B is not particularly limited as long as the film strength can be secured, but it is usually 1-100 μm, preferably 5-50 μm.

Other Layers The process release film of the present embodiment may have layers other than the release layer A, the heat-resistant resin layer B, and the release layer A′ as long as the object of the present invention is not compromised. . For example, an adhesive layer may be provided between the release layer A (or release layer A') and the heat-resistant resin layer B, if necessary. The material used for the adhesive layer is not particularly limited as long as it can firmly bond the release layer A and the heat-resistant resin layer B and does not separate in the resin sealing process and the release process.

For example, when the release layer A (or the release layer A′) contains a 4-methyl-1-pentene copolymer, the adhesive layer is modified 4-methyl-1 graft-modified with an unsaturated carboxylic acid or the like. -Pentene-based copolymer resin, olefin-based adhesive resin composed of 4-methyl-1-pentene-based copolymer and α-olefin-based copolymer, and the like are preferable. When the release layer A (or release layer A') contains a fluororesin, the adhesive layer is preferably a polyester-based, acrylic-based, or fluoro-rubber-based adhesive. The thickness of the adhesive layer is not particularly limited as long as the adhesion between the release layer A (or release layer A') and the heat-resistant resin layer B can be improved, but is, for example, 0.5 to 10 µm.

Method for producing release film for process The method for producing the release film for process of the present invention is not particularly limited, but it is preferably produced by a production method having the following steps.
・A process of blasting the surface of a metal roll using particles with a particle size of 40 to 100 mesh to produce a metal embossing roll. A step of forming unevenness on the surface of the film by passing it through a gap between the above steps. By using the manufacturing method having the above steps, unevenness is formed on at least one of the two surfaces, and the unevenness is formed. The process release film of the present invention, which has an Sdr (developed interface area ratio) of 4.0 to 50.0% as measured by a laser microscope on at least one of the surfaces where the , and Sdr can be set to a desired value with high controllability. Furthermore, it is easy to impart desirable characteristics such as the above-described predetermined RPc (peak count).
In addition, when unevenness is formed on both sides, the film may be passed between the embossing roll and another roll twice, or may be passed between the embossing rolls once. The former method is usually used.

Process for manufacturing metal embossing roll In the method for manufacturing the process release film of the present embodiment, the surface of the metal roll is subjected to blasting treatment using particles having a particle size of 40 to 100 mesh to manufacture the metal embossing roll. a step of
The process of manufacturing the metal embossing roll may have a process operation of blasting the surface of the metal roll using particles with a particle size of 40 to 100 mesh, and has other process operations. Alternatively, the surface of the metal roll may be blasted with particles having a particle size of 40 to 100 mesh without any other process operation. Other process operations include the process of blasting the surface of the metal roll using particles outside the range of particle size 40 to 100 mesh, and the process of forming an uneven pattern by a mill roll method, a resist corrosion method, or the like. operations and the like can be mentioned.

In the method for producing a process release film of the present embodiment, the surface of the metal roll is blasted using particles having a particle size of 40 to 100 mesh, thereby forming a metal embossing roll having an appropriate uneven shape. It is possible to manufacture efficiently, and in the subsequent step, the film is passed between the metal embossing roll and another roll to form unevenness on the film surface, so that at least one of the two surfaces For the process of the present invention, wherein unevenness is formed on the surface, and the Sdr (development interface area ratio) of at least one of the surfaces on which the unevenness is formed, measured with a laser microscope, is 4.0 to 50.0%. The release film can be manufactured with high productivity and controllability.

As the metal roll used in the above step, one having a metal substrate provided on the entire surface of an iron core is preferably used. The metal substrate is not particularly limited as long as it is commonly used for embossing rolls, and examples thereof include metals such as zinc, copper, brass, aluminum, iron, stainless steel, and chromium. Among them, copper is preferable because of the excellent stability of formation of the uneven pattern in the corrosion method.
The thickness of the metal substrate may be set in consideration of the ability to cover the maximum height difference of the uneven pattern of the embossed plate. A thickness of ˜1500 μm is preferred.
The type of embossed pattern is not particularly limited, and may be formed in various shapes such as satin finish and hairline.

(Blasting)
In the manufacturing method of the present invention, the surface of the metal roll is subjected to blasting treatment using particles having a particle size of 40 to 100 mesh at least once to manufacture the metal embossing roll. The blasting treatment may be performed twice or more, in which case particles with a particle size of 40 to 100 mesh may be used in all of the two or more blasting treatments. Particles with particle sizes outside the 100 mesh range may also be used. When blasting is performed twice or more, particles with the same particle size may be used in all of the blasting treatments, or particles with different particle sizes may be used.

By performing blasting using particles with a particle size of 40 to 100 mesh, it becomes easy to control the surface area of the unevenness and to keep the Sdr of the film surface to which the unevenness is transferred within the range of 4.0 to 50. From these points of view, it is preferable because it is easy to control the distance between the irregularities and keep the Rpc of the film surface to which the irregularities are transferred within the range of 30 to 87.
The particle size of the particles used for blasting is particularly preferably 80-100 mesh.
The material of the particles used in the blasting treatment is not particularly limited. For example, inorganic particles such as alumina, iron, silicon carbide, chromium oxide, and iron oxide can be preferably used.

Blasting can be performed, for example, by blowing particles such as those described above from the tip of a nozzle, for example, by the force of compressed air. Specifically, the pressure of the compressed air is preferably in the range of 200-500 kPa. If it is 200 kPa or more, it is possible to form unevenness with a depth that can sufficiently exhibit the effects of the present invention, and if it is 500 kPa or less, it is possible to prevent the above effects from being hindered by destroying the uneven pattern. be able to. From the above point of view, it is more preferable that the pressure range of the compressed air is in the range of 300 to 400 kPa.
The blasting treatment is preferably carried out at room temperature, and the time for which the particles are sprayed is preferably about 0.01 to 0.5 seconds. Further, the nozzle may be scanned so as to satisfy the spraying time condition according to the spraying area of the particles projected from the nozzle.

In the present embodiment, it is preferable to laminate a chromium layer from the viewpoint of imparting a function as a protective layer. The chromium layer may be applied before or after blasting. Also, the chromium layer may be laminated both before and after the blasting treatment.

There are various types of chromium used for lamination of the chromium layer, from chromium smooth enough to have luster to completely matt chromium, and the chromium layer is laminated before or after blasting. It can be selected as appropriate in consideration of crabs and the like.
If the chromium layer is laminated before blasting, it is preferable to use a highly glossy one. A chromium layer that is smoother with higher gloss is more durable and is therefore excellent as a protective layer. Also, the reproducibility as an embossed plate is improved.
Further, when the chromium layer is laminated before the blasting treatment, the thickness of the chromium layer is preferably 30 μm or more so as not to damage the chromium layer by the blasting treatment. Furthermore, in consideration of economic efficiency, etc., the range of 30 to 50 μm is more preferable.

When the chromium layer is laminated after blasting, the thickness of the chromium layer is not particularly limited as long as it can function as a protective layer and the luster can be controlled.
There is no particular limitation on the method of laminating the chromium layer, and the chromium layer can be easily applied by plating, for example. The chromium layer preferably has a Mohs hardness of about 7 (about 6 to 8).

Step of Forming Irregularities on the Film Surface In the manufacturing method of the process release film of the present embodiment, in addition to the above-described step of manufacturing the metal embossing roll, the film is placed between the metal embossing roll and another roll. and forming irregularities on the surface of the film by passing through.
By this step of forming unevenness on the film surface, unevenness is formed on at least one of the two surfaces of the release film for processing of the present invention with high efficiency, and at least one of the surfaces on which the unevenness is formed. Sdr (spread interface area ratio) measured with a laser microscope can be 4.0 to 50.0%.

In this embodiment, the metal embossing roll obtained in the process of manufacturing the metal embossing roll described above is used to form irregularities on the film surface without any particular restrictions on specific operations and conditions. The same operations and conditions as the embossing process in the technical field can be appropriately adopted.
For example, a metal embossing roll with a built-in heater is heated to 60 to 200° C., and a single-layer film or laminated film before unevenness formation is passed between the metal embossing roll and other rolls and pressurized. , can form unevenness.
At that time, the film may be preheated in a drying oven or in contact with a heating roll. The pressure is preferably 30-150 kgf/cm. It is preferable to cool the film after pressurization and shaping.
The metal embossing roll and other rolls are preferably arranged in a suitable apparatus, such as known sheet-fed or rotary embossing machines.

When the release film for process use of the present invention is a laminated film having a release layer A and a heat-resistant resin layer B, the method for producing the release film for process use is not particularly limited.
1) Prior to the step of forming unevenness on the film surface, the release layer A and the heat-resistant resin layer B are co-extruded and laminated to produce a film before unevenness is formed, and the unevenness is formed on the film surface. By subjecting it to the step of performing, a release film for a process can be produced.
2) Alternatively, the molten resin of the release layer A and the adhesive layer is applied and dried on the film that will be the heat-resistant resin layer B, or the resin that will be the release layer A and the adhesive layer is dissolved in a solvent. The film may be manufactured by coating and drying the resin solution obtained before the unevenness is formed.
3) Further, a method of manufacturing a release film for a process by preliminarily manufacturing a film to be a release layer A and a film to be a heat-resistant resin layer B and laminating these films. can also be adopted. In this case, the surface of the film to be the release layer A may be pre-formed with unevenness. That is, only the film to be the release layer A may be subjected to the step of forming unevenness on the film surface.

In the above method 3), as a method for laminating each resin film, various known lamination methods can be employed, such as an extrusion lamination method, a dry lamination method, a heat lamination method, and the like.
In the dry lamination method, each resin film is laminated using an adhesive. As the adhesive, one known as an adhesive for dry lamination can be used. For example, polyvinyl acetate-based adhesives; homopolymers or copolymers of acrylic esters (ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, etc.), or acrylic esters and other monomers (methacrylic acid cyanoacrylate-based adhesives; ethylene and other monomers (vinyl acetate, ethyl acrylate, acrylic acid, methacrylic acid) Ethylene copolymer adhesives made of copolymers, etc.) Cellulose adhesives Polyester adhesives Polyamide adhesives Polyimide adhesives Amino resins made of urea resin or melamine resin Adhesives; Phenolic resin adhesives; Epoxy adhesives; Polyurethane adhesives crosslinked with polyols (polyether polyols, polyester polyols, etc.) and isocyanates and/or isocyanurates; Reactive (meth)acrylic adhesives rubber adhesives such as chloroprene rubber, nitrile rubber and styrene-butadiene rubber; silicone adhesives; inorganic adhesives such as alkali metal silicates and low-melting glass; and other adhesives. As the resin film to be laminated by the method of 3), a commercially available one may be used, or one produced by a known production method may be used. The resin film may be subjected to surface treatment such as corona treatment, atmospheric pressure plasma treatment, vacuum plasma treatment, and primer coating treatment. The method for producing the resin film is not particularly limited, and known production methods can be used.

1) The co-extrusion molding method is preferable in that defects such as foreign matter being caught between the resin layer serving as the release layer A and the resin layer serving as the heat-resistant resin layer B and warping of the release film are less likely to occur. . 3) The lamination method is a suitable manufacturing method when a stretched film is used for the heat-resistant resin layer B. In this case, it is preferable to form an appropriate adhesive layer on the interface between the films as necessary. In order to improve the adhesiveness between the films, the interface between the films may be subjected to surface treatment such as corona discharge treatment, if necessary.

The process release film may optionally be uniaxially or biaxially stretched to increase the film strength of the film.
Stretching may be performed before or after the step of forming unevenness on the film surface. It is preferable to carry out before the step of forming unevenness on the surface.

Although the coating means in the above 2) coating method is not particularly limited, for example, various coaters such as a roll coater, a die coater, and a spray coater are used. The melt extrusion means is not particularly limited, but for example, an extruder having a T-type die or an inflation type die is used.

Form of use of process release film (manufacturing process)
The process release film of the present invention can be used by placing it between the semiconductor chip or the like and the inner surface of the mold when the semiconductor chip or the like is placed in the mold and resin is injected and molded. By using the process release film of the present invention, it is possible to effectively prevent mold release failure, burr generation, and the like.
The resin used in the above manufacturing process may be either a thermoplastic resin or a thermosetting resin, but thermosetting resins are widely used in the technical field, and epoxy-based thermosetting resins are particularly used. It is preferable to use
The most typical example of the manufacturing process is the sealing of semiconductor chips, but the present invention is not limited to this, and can also be applied to fiber-reinforced plastic molding processes, plastic lens molding processes, and the like. .

FIG. 1 is a schematic diagram showing an example of a method for producing a resin-encapsulated semiconductor using the release film of the present invention.
As shown in FIG. 1a, the release film 1 of the present invention is fed into a mold 8 from a roll-shaped roll by rolls 1-2 and 1-3. Next, the release film 1 is arranged on the inner surface of the upper mold 2 . At this time, the inner surface of the upper mold 2 is evacuated from the suction port 3 to bring the release film 1 into close contact with the inner surface of the upper mold 2 . Since the process release film 1 of the present invention is excellent in deaeration in the lateral direction, the deaeration time is shortened, and resin-encapsulated semiconductors can be produced with high productivity. Moreover, since the adhesion to the inner surface of the upper mold 2 is also excellent, the occurrence of wrinkles is suppressed, and a resin-encapsulated semiconductor with a good appearance can be manufactured. In order to realize these remarkable effects, in the present embodiment, the surface on which the unevenness is formed and the surface having an Sdr (development interface area ratio) of 4.0 to 50.0% is used as the upper die. 2 Arrange so as to face the inner surface.
A semiconductor chip 6 arranged on a substrate is arranged in a lower mold 5 of a molding machine, and a sealing resin is arranged on the semiconductor chip 6, or a liquid sealing resin is applied so as to cover the semiconductor chip 6. By injecting the sealing resin 4, the sealing resin 4 is accommodated between the upper mold 2 and the lower mold 5 on which the release film 1 is placed and which is exhausted and sucked. Next, as shown in FIG. 1b, the upper mold 2 and the lower mold 5 are closed via the release film 1 of the present invention, and the sealing resin 4 is cured.

As shown in FIG. 1c, the sealing resin 4 is fluidized in the mold by the mold closing and hardening, and the sealing resin 4 flows into the space and surrounds the side surface of the semiconductor chip 6, thereby filling the sealed semiconductor. The upper mold 2 and the lower mold 5 are opened and the chip 6 is taken out. After the mold is opened and the molded product is taken out, the release film 1 is repeatedly used, or a new release film is supplied, and the next resin molding is performed.

The release film of the present invention is adhered to the upper mold, interposed between the mold and the sealing resin, and resin-molded to prevent the resin from adhering to the mold and prevent the resin mold surface of the mold from becoming dirty. and the molded article can be easily released from the mold.
It should be noted that the release film can be newly supplied for each resin molding operation and resin-molded, or can be newly supplied for each resin-molding operation to be resin-molded.

The encapsulating resin may be a liquid resin or a resin that is solid at room temperature, but a sealing material that becomes liquid when resin-encapsulated can be used as appropriate. Specifically, epoxy resins (biphenyl type epoxy resins, bisphenol epoxy resins, o-cresol novolac type epoxy resins, etc.) are mainly used as sealing resin materials, and polyimide resins ( Bismaleimide-based resins), silicone-based resins (thermosetting addition type), and the like, which are commonly used as encapsulating resins, can be used. The resin sealing conditions may vary depending on the sealing resin used, but may be appropriately set, for example, within the range of curing temperature of 120° C. to 180° C., molding pressure of 10 to 50 kg/cm ² , and curing time of 1 to 60 minutes. can.

Before and after the step of arranging the release film 1 on the inner surface of the mold 8 and the step of arranging the semiconductor chip 6 in the mold 8 are not particularly limited. The release film 1 may be placed after placement, or the semiconductor chip 6 may be placed after the release film 1 is placed.

As described above, the process release film 1 of the present invention has high releasability, so that the semiconductor package 4-2 can be easily released from the mold. Moreover, since the release film 1 has an appropriate degree of flexibility, it is difficult to wrinkle due to the heat of the molding die 8 while being excellent in followability to the shape of the die. Therefore, the sealed semiconductor package 4-2 with good appearance is prevented from being transferred wrinkles to the resin-sealed surface of the sealed semiconductor package 4-2 and without causing a portion not filled with resin (resin chipping). You can get 4-2.
Furthermore, since the release film 1 is excellent in degassing property in the horizontal direction, degassing time is shortened when it is brought into close contact with the inner surface of the upper mold 2, and resin-encapsulated semiconductors can be manufactured with high productivity.

The method for manufacturing a resin-encapsulated semiconductor using the process release film of the present invention is not limited to the compression molding method in which the solid encapsulating resin material 4 is pressurized and heated as shown in FIG. A transfer molding method for injecting a sealing resin material may be employed.

The release film of the present invention is not limited to the process of resin-encapsulating a semiconductor element, but also the process of molding and releasing various molded products using a molding die, such as fiber-reinforced plastic molding and mold release process, plastic lens molding Also, it can be preferably used in the mold release step and the like.

The present invention will be described in more detail below with reference to examples, but the present invention is not limited by these.

In the following examples/comparative examples, physical properties/characteristics were evaluated by the following methods.
(Development interface area ratio (Sdr))
The film was vacuum-sucked on the vacuum-sucking plate, and the whole plate was placed on the measurement stage of the laser microscope. A laser microscope image was obtained under the following conditions to determine the Sdr of the uneven surface (release layer A side).
Apparatus: laser microscope (OLS5000, manufactured by Olympus Corporation)
Objective lens: MPLAPON50XLET
Measurement area: 720 x 720 μm (image connection of a total of 9 areas of 3 x 3 in length and width)
Automatic deskewing: Enabled Filtering: None

(Peak count (RPc))
The peak count of the uneven surface (release layer A side) was measured based on JIS B0601:2013 (ISO4287:1997, Amd.1:2009). The reference length was set to 10 mm. In the measurement, a surface roughness measuring machine SURFCOM 130A (manufactured by Tokyo Seimitsu Co., Ltd.) was used, and three points were measured in the direction (TD direction) perpendicular to the flow direction during film production, and in the direction parallel (MD direction ), the RPc was determined for a total of 6 locations (3 locations), and the average value thereof was taken as the RPc of the surface.

Contact angle with water (water contact angle)
According to JIS R3257, the water contact angle of the film surface (both sides) was measured using a contact angle measuring instrument (Kyowa Interface Science, FACECA-W).

(tensile modulus)
According to JIS K7127, the tensile modulus at 120° C. and 170° C. was determined using a tensile tester with a constant temperature bath “RTC-1225” manufactured by A&D Co., Ltd.
Measurement conditions: Tensile mode Measurement direction: Film longitudinal (MD) direction (film transport direction)

(Degassing time)
As shown in FIG. 1( a ), the release film for process is arranged with a tension of 10 N applied between the upper mold and the lower mold (the uneven surface (release layer A side) is on the upper mold side ), and then vacuum-adsorbed to the parting surface of the upper mold. At this time, the time required for the air to completely escape was measured.
WCM-300MS manufactured by Apic Yamada Co., Ltd. was used as a semiconductor encapsulation molding apparatus. A mold having a circular parting surface of the upper mold with a diameter of 300 mm was used. The mold temperature was 120°C.

(Releasability)
In the same manner as in the evaluation of the degassing time, the process release film was vacuum-adsorbed to the parting surface of the upper mold (the uneven surface (release layer A side) was the upper mold side), and then the substrate was placed so as to cover the semiconductor chip. A semiconductor chip fixed to the substrate was placed on the lower mold and clamped. At this time, the mold temperature (molding temperature) was 120° C., the molding pressure was 10 MPa, and the molding time was 400 seconds. Then, as shown in FIG. 1C, after the semiconductor chip was sealed with a sealing resin, the resin-sealed semiconductor chip (semiconductor package) was released from the release film.
The releasability of the release film was evaluated according to the following criteria.
⊚: The release film is naturally peeled off at the same time as the mold is opened.
◯: The release film does not peel off naturally, but can be easily peeled off by hand pulling (applying tension).
x: The release film adhered to the resin sealing surface of the semiconductor package and could not be peeled off by hand.

(Appearance of molded product)
The wrinkles of the release film and the resin sealing surface of the semiconductor package after the release was performed in the above steps were evaluated according to the following criteria.
⊚: No wrinkles at all on either the release film or the semiconductor package.
◯: The release film has slight wrinkles, but the wrinkles are not transferred to the semiconductor package.
x: There are many wrinkles not only on the release film but also on the semiconductor package.

(mold followability)
The mold followability of the release film when the mold was released in the above steps was evaluated according to the following criteria.
⊚: There is no resin chipping (portion not filled with resin) in the semiconductor package.
○: There is a slight chipping of resin at the edge of the semiconductor package (excluding chipping due to wrinkles)
×: There are many resin chippings at the edge of the semiconductor package (excluding chippings due to wrinkles)

[Example 1]
(Heat-resistant resin layer B)
As the heat-resistant resin layer B, a biaxially oriented PET (polyethylene terephthalate) film (manufactured by Toray Industries, Inc., product name: Lumirror S10) having a film thickness of 12 μm was used.
(Release layers A and A')
Unstretched 4-methyl-1-pentene copolymer resin films were used as the release layers A and A'. Specifically, a 4-methyl-1-pentene copolymer resin manufactured by Mitsui Chemicals, Inc. (product name: TPX (registered trademark), brand name: MX022)" is melt extruded at 270 ° C., and the slit width of the T-shaped die is A non-stretched film having a thickness of 15 μm was formed by adjusting the .
For the unstretched 4-methyl-1-pentene copolymer resin film, if one film surface has a water contact angle of 30° or more based on JIS R3257, the adhesiveness is improved by using an adhesive so that the water contact angle is 30° or less. Corona treatment was applied from the point of view.

(glue)
Urethane-based adhesive A below was used as the adhesive used in the dry lamination step for laminating each film.
[Urethane adhesive A]
Main agent: Takelac (registered trademark) A-616 (manufactured by Mitsui Chemicals, Inc.). Curing agent: Takenate (registered trademark) A-65 (manufactured by Mitsui Chemicals, Inc.). The main agent and the curing agent were mixed so that the mass ratio (main agent:curing agent) was 16:1, and ethyl acetate was used as the diluent.

(Manufacture of laminated film)
On one side of a biaxially stretched PET (polyethylene terephthalate) film, urethane-based adhesive A was applied at 1.5 g/m ² by gravure coating, and a non-stretched 4-methyl-1-pentene copolymer resin film was obtained. After laminating the corona-treated surface by dry lamination, urethane-based adhesive A was applied at 1.5 g/m ² to the biaxially oriented PET (polyethylene terephthalate) film surface side of the laminate film. The corona-treated surface of the stretched 4-methyl-1-pentene copolymer resin film is laminated by dry lamination to form a five-layer structure (release layer A / adhesive layer / heat-resistant resin layer B / adhesive layer / release layer A ') was obtained.
Dry lamination conditions were as follows: base material width 900 mm, transport speed 30 m/min, drying temperature 50 to 60° C., lamination roll temperature 50° C., roll pressure 3.0 MPa.

(Manufacture of metal embossing rolls)
The surface of a carbon steel roll having a face length of 570 mm and a diameter of 200 mm was uniformly blasted with alumina particles having a grain size of 80 mesh. After that, hard chrome plating with a thickness of 15 μm was applied to manufacture a metal embossing roll for forming unevenness.

(Formation of unevenness)
A laminate film having a five-layer structure (release layer A/adhesive layer/heat-resistant resin layer B/adhesive layer/release layer A′) prepared above is placed between the pair of metal embossing rolls and rubber rolls prepared above. , and unevenness was imparted to the release layer A side surface of the film to prepare a process release film of Example 1.
The conditions for embossing were a conveying speed of 5 m/min, a metal embossing roll temperature of 120° C., and an inter-roll pressure of 75 kgf/cm.

Table 1 shows the evaluation results of the surface roughness (Sdr and RPc), water contact angle, tensile modulus, degassing time, releasability, wrinkles, and mold followability of the process release film produced above. .
When using the process release film of Example 1 whose surface Sdr (spread surface area ratio) satisfies the conditions of the present invention, it is possible to completely deaerate the air between the upper mold and the film in a short deaeration time. did it.
In addition, the release film exhibits good releasability in that it is naturally peeled off at the same time as the mold is opened, and neither the release film nor the semiconductor package has any wrinkles. It exhibited excellent mold followability with no resin chipping.
That is, the process release film of Example 1 was a process release film that had a short degassing time and excellent releasability, suppression of wrinkles, and mold followability.

[Example 2]
In the production of the metal embossing roll, a process release film was produced in the same manner as in Example 1, except that the alumina particles with a particle size of 40 mesh and then alumina particles with a particle size of 100 mesh were uniformly blasted in that order. ,evaluated.
The results are shown in Table 1.
The process release film had a shorter degassing time than that of Example 1, and had good releasability, suppression of wrinkles, and mold followability.

[Example 3]
In the production of the metal embossing roll, a process release film was produced in the same manner as in Example 1, except that the alumina particles with a particle size of 80 mesh and then alumina particles with a particle size of 100 mesh were uniformly blasted in that order. ,evaluated.
The results are shown in Table 1.
The process release film had a shorter degassing time than that of Example 1, and had good releasability, suppression of wrinkles, and mold followability.

[Example 4]
A process release film was produced and evaluated in the same manner as in Example 1, except that the temperature of the metal embossing roll was set to 150° C. when forming the irregularities on the film surface.
The results are shown in Table 1.
The process release film had a shorter degassing time than that of Example 1, and had good releasability, suppression of wrinkles, and mold followability.

[Comparative Example 1]
In the production of the metal embossing roll, a process release film was produced and evaluated in the same manner as in Example 1, except that alumina particles with a particle size of 100 mesh were uniformly blasted.
The results are shown in Table 1.
Although the process release film had good releasability, wrinkle suppression, and mold followability, the degassing time was longer than in each of the above examples.

The process release film of the present invention exhibits high degassing properties that could not be achieved by conventional techniques, and also exhibits high degassing properties, excellent releasability, wrinkle suppression performance, and mold followability compared to conventional technologies. Since it is combined at a high level that exceeds the limit, by using this, it is possible to manufacture molded products obtained by resin-sealing semiconductor chips etc. with high productivity and quality beyond the limits of conventional technology. It brings about technical effects of high practical value, such as being able to make it possible, and has high applicability in various fields of industry including the semiconductor process industry.
In addition, the process release film of the present invention can be used not only for semiconductor packages but also for various mold molding processes such as fiber-reinforced plastic molding processes and plastic lens molding processes. It has high applicability in each field of industry that conducts

1, 1-2, 1-3: Release film 2: Upper mold 3: Suction port 4: Sealing resin 4-2: Semiconductor package 5: Lower mold 6: Semiconductor chip 7: Substrate 8: Molding mold

Claims

A process in which unevenness is formed on at least one of the two surfaces, and the surface on which the unevenness is formed has an Sdr (development interface area ratio) measured with a laser microscope of 4.0 to 50.0%. release film.
2. The process release film according to claim 1, wherein the RPc (peak count) of the surface on which the irregularities are formed and whose Sdr (spread interface area ratio) is 4.0 to 50.0% is 30 to 87. .
The water contact angle of the surface opposite to the surface on which the unevenness is formed and the Sdr (development interface area ratio) is 4.0 to 50.0% is 90 to 130°. A release film for the described process.
The process release film according to any one of claims 1 to 3, which has a thickness of 10 to 100 µm.
The process release film according to any one of claims 1 to 4, which has a tensile modulus at 120°C of 30 to 500 MPa.
The process release film according to any one of claims 1 to 5, which has a tensile modulus at 170°C of 20 to 400 MPa.
A step of blasting the surface of the metal roll with particles having a particle size of 40 to 100 mesh to produce a metal embossing roll, and passing the film between the metal embossing roll and another roll forming irregularities on the surface of the film;
The method for producing a process release film according to any one of claims 1 to 6.
The process release film according to any one of claims 1 to 6, which is used in a semiconductor encapsulation process.
A method for manufacturing a resin-encapsulated semiconductor,
A step of placing a semiconductor device to be resin-sealed at a predetermined position in a molding die;
The process release film according to any one of claims 1 to 6 is applied to the inner surface of the molding die, and the unevenness is formed and the Sdr (development interface area ratio) is 4.0 to 50.0%. a step of arranging the surface so that it faces the inner surface of the molding die;
deaeration between the process release film and the inner surface of the mold;
A step of curing the encapsulating resin disposed between the semiconductor device and the release film for semiconductor encapsulation process after clamping the mold;
A method for manufacturing the resin-encapsulated semiconductor.