JP2021028177A - Release film for processing, application thereof and manufacturing method of resin encapsulated semiconductor using the same - Google Patents

Abstract

To provide a release film for processing capable of easily release a molded article after resin encapsulation from a mold without depending on a mold structure or a mold releasing agent amount and capable of providing the molded article without appearance defect such as wrinkle or crack.SOLUTION: There is provided a release film for processing which is a laminate film including a mold release layer A, a heat resistant resin layer B and a mold release layer A' if needed, wherein contact angle of the mold release layer A (and the mold release layer A' if present) to water is 90° to 130°, thermal dimensional change rate from 23°C to 120°C in a crosswise (TD) direction of the laminate film is 3% or less or thermal dimensional change rate from 23°C to 170°C in the crosswise (TD) direction of the laminate film is 4% or less.SELECTED DRAWING: Figure 1

Description

The present invention relates to a release film for a process, preferably a release film for a semiconductor encapsulation process, and particularly when a semiconductor chip or the like is placed in a mold and a resin is injected and molded, the semiconductor chip or the like and the inner surface of the mold are formed. The present invention relates to a release film for a process arranged between and, and a method for manufacturing a resin-sealed semiconductor using the same.

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

Examples of such a release film include a fluororesin film (for example, Patent Documents 1 and 2) and a poly-4-methyl-1-pentene resin film (for example, Patent Document 3), which are excellent in releasability and heat resistance. Proposed. However, these release films have a problem that wrinkles are likely to occur when they are attached to the inner surface of the mold, and these wrinkles are transferred to the surface of the molded product, resulting in poor appearance.

On the other hand, a laminated release film having a release layer and a heat-resistant layer has been proposed. In these release films, a release layer is used to obtain releasability, and a heat-resistant layer is used to suppress wrinkles. A typical example of these proposals focuses on the relationship between the storage elastic modulus of the release layer and the heat-resistant layer (see, for example, Patent Documents 4 and 5). For example, Patent Document 4 describes a laminated release film having a structure in which the storage elastic modulus of the release layer is relatively low and the storage elastic modulus of the heat-resistant layer is relatively high, more specifically, at 175 ° C. of the release layer. A release film for a semiconductor encapsulation process is described in which the storage elastic modulus E'is 45 MPa or more and 105 MPa or less, and the heat-resistant layer has a storage elastic modulus E'at 100 MPa or more and 250 MPa or less at 175 ° C.

Japanese Unexamined Patent Publication No. 2001-310336 JP-A-2002-110722 Japanese Unexamined Patent Publication No. 2002-361643 JP-A-2010-208104 International Publication No. 2015/133631 A1 Pamphlet

However, with the development of the technical field, the required level for process release films such as release films for semiconductor encapsulation processes is increasing year by year, and process release with suppressed wrinkles even under more severe process conditions. There is a strong demand for a mold release film, and in particular, a mold release film for a process in which mold releasability, wrinkle suppression, and mold followability are balanced at a higher level.

The present invention has been made in view of such circumstances, and a molded product after resin sealing can be easily released without depending on the mold structure and the amount of mold release agent, and the appearance such as wrinkles and chips can be easily removed. It is an object of the present invention to provide a release film for a process capable of obtaining a molded product without defects.

As a result of diligent studies to solve the above problems, the present inventors have found that the rate of change in thermal dimensions of the process release film at a specific temperature, particularly the TD direction of the laminated film constituting the process release film (film). It is mounted on the inner surface of the mold to appropriately control the rate of change in thermal dimensions in the direction perpendicular to the longitudinal direction at the time of film production, also referred to as the "lateral direction"). We have found that it is important for suppressing wrinkles at the time, and have completed the present invention.
That is, the present invention and each aspect thereof are as described in the following [1] to [19].

[1]
A release film for a process, which is a laminated film containing a release layer A and a heat-resistant resin layer B.
The contact angle of the release layer A with water (hereinafter, "contact angle with water" may be referred to as "water contact angle") is 90 ° to 130 °.
The release film for a process, wherein the heat-resistant resin layer B has a thermal dimensional change rate of 3% or less from 23 ° C. to 120 ° C. in the lateral (TD) direction.
[2]
The sum of the thermal dimensional change rate from 23 ° C. to 120 ° C. in the lateral (TD) direction and the thermal dimensional change rate from 23 ° C. to 120 ° C. in the longitudinal (MD) direction of the laminated film is 6% or less [1]. ]. The release film for the process described in.
[3]
A release film for a process, which is a laminated film containing a release layer A and a heat-resistant resin layer B.
The contact angle of the release layer A with water is 90 ° to 130 °.
The release film for a process, wherein the heat-resistant resin layer B has a thermal dimensional change rate of 4% or less from 23 ° C. to 170 ° C. in the lateral (TD) direction.
[4]
The sum of the thermal dimensional change rate from 23 ° C. to 170 ° C. in the lateral (TD) direction and the thermal dimensional change rate from 23 ° C. to 170 ° C. in the longitudinal (MD) direction of the laminated film is 7% or less, [3 ]. The release film for the process described in.
[5]
The release film for a process according to any one of [1] to [4], wherein the heat-resistant resin layer B has a thermal dimensional change rate of 3% or less from 23 ° C. to 120 ° C. in the lateral (TD) direction.
[6]
The sum of the thermal dimensional change rate from 23 ° C. to 120 ° C. in the lateral (TD) direction and the thermal dimensional change rate from 23 ° C. to 120 ° C. in the longitudinal (MD) direction of the heat-resistant resin layer B is 6% or less. The release film for a process according to [5].
[7]
The release film for a process according to any one of [1] to [4], wherein the heat-resistant resin layer B has a thermal dimensional change rate of 3% or less from 23 ° C. to 170 ° C. in the lateral (TD) direction.
[8]
The sum of the thermal dimensional change rate from 23 ° C. to 170 ° C. in the lateral (TD) direction and the thermal dimensional change rate from 23 ° C. to 120 ° C. in the longitudinal (MD) direction of the heat-resistant resin layer B is 4% or less. The release film for a process according to [7].
[9]
In any one of [1] to [8], the release layer A contains a resin selected from the group consisting of a fluororesin, a 4-methyl-1-pentene (co) polymer, and a polystyrene-based resin. The release film for the described process.
[10]
The process release film according to any one of [1] to [9], wherein the heat-resistant resin layer B contains a stretched film.
[11]
The release film for a process according to [10], wherein the stretched film is selected from the group consisting of a stretched polyester film, a stretched polyamide film, and a stretched polypropylene film.
[12]
The amount of heat of crystal melting in the first heating step measured by differential scanning calorimetry (DSC) according to JIS K7221 of the heat-resistant resin layer B is 15 J / g or more and 60 J / g or less, [1] to [11]. The release film for the process according to any one of the above.

[13]
The laminated film further has a release layer A', and includes the release layer A, the heat-resistant resin layer B, and the release layer A'in this order.
The process release film according to any one of [1] to [12], wherein the release layer A'has a contact angle with water of 90 ° to 130 °.
[14]
At least one of the release layer A and the release layer A'contains a resin selected from the group consisting of a fluororesin, a 4-methyl-1-pentene (co) polymer, and a polystyrene-based resin [13]. Release film for the process described in.
[15]
The process release film [16] according to any one of [1] to [14], which is used in the sealing process using a thermosetting resin.
The process release film according to any one of [1] to [15], which is used in a semiconductor encapsulation process.
[17]
The release film for a process according to any one of [1] to [15], which is used in a fiber reinforced plastic molding process or a plastic lens molding process.
[18]
A method for manufacturing resin-sealed semiconductors.
The process of arranging the resin-sealed semiconductor device at a predetermined position in the molding die,
A step of arranging the release film for the semiconductor encapsulation process according to any one of [1] to [14] on the inner surface of the molding die so that the release layer A faces the semiconductor device. ,
A step of injecting and molding a sealing resin between the semiconductor device and the release film for the semiconductor sealing process after molding the molding die.
The above-mentioned method for manufacturing a resin-sealed semiconductor.
[19]
A method for manufacturing resin-sealed semiconductors.
The process of arranging the resin-sealed semiconductor device at a predetermined position in the molding die,
A step of arranging the release film for the semiconductor encapsulation process according to [13] or [14] on the inner surface of the molding die so that the release layer A'is opposed to the semiconductor device.
A step of injecting and molding a sealing resin between the semiconductor device and the release film for the semiconductor sealing process after molding the molding die.
The above-mentioned method for manufacturing a resin-sealed semiconductor.

The process release film of the present invention has a high level of releasability, wrinkle suppression, and mold followability that could not be realized by the prior art. Therefore, by using this, a semiconductor chip or the like is sealed with a resin. The molded product obtained by the above can be easily released from the mold, and the molded product without appearance defects such as wrinkles and chips can be manufactured with high productivity.

It is a schematic diagram which shows an example of the release film for process of this invention. It is a schematic diagram which shows another example of the release film for process of this invention. It is a schematic diagram which shows an example of the manufacturing method of the resin-sealed semiconductor using the release film for process of this invention. It is a schematic diagram which shows an example of the manufacturing method of the resin-sealed semiconductor using the release film for process of this invention. It is a schematic diagram which shows an example of the manufacturing method of the resin-sealed semiconductor using the release film for process of this invention. It is a schematic diagram which shows an example of the resin-sealed semiconductor obtained by the manufacturing method of the resin-sealed semiconductor of FIG. 4A and FIG. 4B.

Release film for process The release film for process of the present invention includes the following four aspects.
(First aspect)
A release film for a process, which is a laminated film containing a release layer A and a heat-resistant resin layer B.
The contact angle of the release layer A with water is 90 ° to 130 °.
The release film for a process, wherein the rate of change in thermal dimension from 23 ° C. to 120 ° C. in the lateral (TD) direction of the laminated film is 3% or less.
(Second aspect)
A release film for a process, which is a laminated film containing a release layer A and a heat-resistant resin layer B.
The contact angle of the release layer A with water is 90 ° to 130 °.
The release film for a process, wherein the rate of change in thermal dimension from 23 ° C. to 170 ° C. in the lateral (TD) direction of the laminated film is 4% or less.
(Third aspect)
A release film for a process, which is a laminated film containing a release layer A, a heat-resistant resin layer B, and a release layer A'in this order.
The contact angles of the release layer A and the release layer A'with respect to water are 90 ° to 130 °.
The release film for a process, wherein the rate of change in thermal dimension from 23 ° C. to 120 ° C. in the lateral (TD) direction of the laminated film is 3% or less.
(Fourth aspect)
A release film for a process, which is a laminated film containing a release layer A, a heat-resistant resin layer B, and a release layer A'in this order.
The contact angles of the release layer A and the release layer A'with respect to water are 90 ° to 130 °.
The release film for a process, wherein the rate of change in thermal dimension from 23 ° C. to 170 ° C. in the lateral (TD) direction of the laminated film is 4% or less.

As is clear from each of the above aspects, the release film for the process of the present invention (hereinafter, also simply referred to as "release film") is a release layer A having a mold release property with respect to a molded product or a mold, and optionally. It is a laminated film including a release layer A'and a heat-resistant resin layer B that supports the release layer.

The release film for a process of the present invention is arranged on the inner surface of the molding die when the semiconductor element or the like is resin-sealed inside the molding die. At this time, the release layer A of the release film (which may be the release layer A'if the release layer A'is present) is placed on the resin-sealed semiconductor element or the like (molded product) side. It is preferable to arrange it. By arranging the release film of the present invention, the resin-sealed semiconductor element or the like can be easily released from the mold.
The contact angle of the release layer A with water is 90 ° to 130 °, and by having such a contact angle, the release layer A has low wettability and adheres to the cured sealing resin or mold surface. The molded product can be easily released without any need.
The contact angle of the release layer A with water is preferably 95 ° to 120 °, more preferably 98 ° to 115 °, and even more preferably 100 ° to 110 °.

As described above, since the release layer A (in some cases, the release layer A') is arranged on the molded product side, wrinkles in the release layer A (in some cases, the release layer A') in the resin sealing step. It is preferable to suppress the occurrence of. This is because there is a high possibility that the generated wrinkles are transferred to the molded product and the appearance of the molded product is deteriorated.

In the present invention, in order to achieve the above object, the release layer A (and the release layer A'if desired) and the heat-resistant resin supporting the release layer are used as the laminated film constituting the release film for the process. A laminated film containing the layer B, wherein the rate of change in thermal dimension in the lateral (TD) direction shows a specific value.
That is, the laminated film containing the release layer A (and, if desired, the release layer A') and the heat-resistant resin layer B supporting the release layer is from 23 ° C. to 120 ° C. in the TD direction (horizontal direction). The thermal dimensional change rate of the above is 3% or less, or the thermal dimensional change rate from 23 ° C. to 170 ° C. in the TD direction (lateral direction) is 4% or less. Further, the laminated film has a thermal dimensional change rate of 3% or less from 23 ° C. to 120 ° C. in the TD direction (horizontal direction) and a thermal dimensional change from 23 ° C. to 170 ° C. in the TD direction (horizontal direction). More preferably, the rate is 4% or less.
The thermal dimensional change rate from 23 ° C. to 120 ° C. in the TD direction (horizontal direction) of the laminated film is 3% or less, or the thermal dimensional change from 23 ° C. to 170 ° C. in the TD direction (horizontal direction). When the rate is 4% or less, the occurrence of wrinkles in the release layer in the resin sealing step or the like can be effectively suppressed. The mechanism by which the generation of wrinkles in the release layer is suppressed by using a laminated film that constitutes the release film for the process and whose thermal dimensional change rate in the lateral (TD) direction shows the above specific value is not always clear. Although not, it is related to the fact that the thermal expansion / contraction of the release layer A (or the release layer A') due to heating / cooling during the process is suppressed by using the laminated film having a relatively small thermal expansion / contraction. It is presumed that there is.

The laminated film constituting the process release film of the present invention preferably has a thermal dimensional change rate of 2.5% or less, preferably 2.0%, from 23 ° C. to 120 ° C. in the TD direction (horizontal direction). It is more preferably less than or equal to, and even more preferably 1.5% or less. On the other hand, the laminated film preferably has a thermal dimensional change rate of −5.0% or more from 23 ° C. to 120 ° C. in the TD direction (horizontal direction).
The laminated film constituting the process release film of the present invention preferably has a thermal dimensional change rate of 3.5% or less, preferably 3.0%, from 23 ° C. to 170 ° C. in the TD direction (horizontal direction). It is more preferably less than or equal to, and even more preferably 2.0% or less. On the other hand, the laminated film preferably has a thermal dimensional change rate of −5.0% or more from 23 ° C. to 170 ° C. in the TD direction (horizontal direction).

By using a resin layer whose thermal dimensional change rate in the lateral (TD) direction shows the above-mentioned specific value as the heat-resistant resin layer B, the mechanism by which the generation of wrinkles in the release layer is suppressed more effectively is not necessarily clear. However, by using the heat-resistant resin layer B having a relatively small thermal expansion / contraction, the thermal expansion / contraction of the release layer A (or the release layer A') due to heating / cooling during the process is suppressed. It is presumed that it is related to.

The release film for a process of the present invention, which is a laminated film containing a release layer A (and a release layer A'if desired) and a heat-resistant resin layer B supporting the release layer, is in the TD direction (lateral direction). ) And the thermal dimensional change rate in the MD direction (longitudinal direction at the time of film production, hereinafter also referred to as "longitudinal direction") are preferably not more than a specific value.
That is, the sum of the thermal dimensional change rate from 23 ° C. to 120 ° C. in the horizontal (TD) direction and the thermal dimensional change rate from 23 ° C. to 120 ° C. in the longitudinal (MD) direction of the laminated film is 6% or less. On the other hand, the laminated film is the sum of the thermal dimensional change rate from 23 ° C. to 120 ° C. in the TD direction (horizontal direction) and the thermal dimensional change rate from 23 ° C. to 120 ° C. in the longitudinal (MD) direction. Is preferably −5.0% or more.
The rate of change in thermal dimensions from 23 ° C. to 120 ° C. in the lateral (TD) direction and the longitudinal (MD) direction of the laminated film containing the release layer A (and the release layer A'if desired) and the heat-resistant resin layer B. When the sum of the thermal dimensional change rates from 23 ° C. to 120 ° C. is 6% or less, the occurrence of wrinkles when mounted on the inner surface of the mold can be more effectively suppressed.

Further, the rate of change in thermal dimensions from 23 ° C. to 170 ° C. in the lateral (TD) direction and the longitudinal (MD) of the laminated film containing the release layer A (and the release layer A'if desired) and the heat-resistant resin layer B. The sum of the thermal dimensional change rates from 23 ° C. to 170 ° C. in the direction is preferably 7% or less, while the laminated film has a thermal dimension from 23 ° C. to 170 ° C. in the TD direction (horizontal direction). The sum of the rate of change and the rate of change in thermal dimensions from 23 ° C to 170 ° C in the longitudinal (MD) direction is preferably −5.0% or more.
The sum of the thermal dimensional change rate from 23 ° C. to 170 ° C. in the horizontal (TD) direction and the thermal dimensional change rate from 23 ° C. to 170 ° C. in the longitudinal (MD) direction of the laminated film is 7% or less. It is possible to more effectively suppress the occurrence of wrinkles when the mold is mounted on the inner surface of the mold.

Release layer A
The release layer A constituting the process release film of the present invention has a contact angle with water of 90 ° to 130 °, preferably 95 ° to 120 °, and more preferably 98 ° to 115 °. More preferably, it is 100 ° to 110 °. It is preferable to contain a resin selected from the group consisting of a fluororesin, a 4-methyl-1-pentene (co) polymer, and a polystyrene-based resin because of excellent mold releasability of the molded product and easy availability.

The fluororesin that can be used for the release layer A may be a resin containing a structural unit derived from tetrafluoroethylene. It may be a homopolymer of tetrafluoroethylene, or it may be a copolymer with another olefin. Examples of other olefins include ethylene. A copolymer containing tetrafluoroethylene and ethylene as a monomer constituent unit is a preferable example. In such a copolymer, the proportion of the constituent unit derived from tetrafluoroethylene is 55 to 100% by mass, and ethylene is used. The proportion of the structural unit derived from is preferably 0 to 45% by mass.

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

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 copolymerized with 4-methyl-1-pentene is 4-methyl. -1-It can impart flexibility to pentene. Examples of olefins having 2 to 20 carbon atoms include ethylene, propylene, 1-butene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-tetradecene, 1-hexadecene, 1-heptadecene, 1 -Includes octadecene, 1-eikosen, etc. Only one of these olefins may be used, or two or more of these olefins may be used in combination.

In the case of a copolymer of 4-methyl-1-pentene and an olefin having 2 to 20 carbon atoms, the proportion of structural units derived from 4-methyl-1-pentene is 96 to 99% by mass, and other than that. The proportion of the structural unit derived from the olefin having 2 to 20 carbon atoms is preferably 1 to 4% by mass. By reducing the content of the constituent units derived from olefins having 2 to 20 carbon atoms, the copolymer can be made hard, that is, the storage elastic modulus E'can be increased, and wrinkles can be suppressed in the sealing step or the like. It is advantageous to. On the other hand, by increasing the content of the structural unit derived from the olefin having 2 to 20 carbon atoms, the copolymer can be made soft, that is, the storage elastic modulus E'can be lowered, and the 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 a known catalyst such as a Ziegler-Natta catalyst or a metallocene catalyst. 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, but in particular, the copolymer having an isotactic structure. Is preferable from the viewpoint of physical properties, and is easily available. Furthermore, as long as the 4-methyl-1-pentene (co) polymer can be molded into a film and has strength to withstand the temperature and pressure during mold molding, its stereoregularity and molecular weight are particularly limited. Not done. The 4-methyl-1-pentene copolymer may be a commercially available copolymer such as TPX (registered trademark) manufactured by Mitsui Chemicals, Inc.

The polystyrene-based resin that can be used for the release layer A includes a homopolymer and a copolymer of styrene, and the structural unit derived from styrene contained in the polymer is at least 60% by weight or more. It is preferably, more preferably 80% by weight or more.
The polystyrene-based resin may be isotactic polystyrene or syndiotactic polystyrene, but isotropic polystyrene is preferable from the viewpoint of transparency, availability, etc., and has mold releasability, heat resistance, etc. From this point of view, 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 at the time of 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, in a fluororesin, it is preferable to contain at least a structural unit derived from tetrafluoroethylene, and in a 4-methyl-1-pentene (co) polymer, 4-methyl-1. -It is preferable to contain at least a structural unit derived from penten, and it is preferable that the polystyrene-based resin contains at least syndiotactic polystyrene. Since the resin constituting the release layer A contains a crystal component, wrinkles are less likely to occur in the resin sealing step or the like, and it is suitable for suppressing the transfer of wrinkles to the molded product to cause poor appearance. ..

The resin containing the above crystalline component constituting the release layer A has a crystal melting heat amount of 15 J / g or more and 60 J / g or less in the first temperature raising step measured by differential scanning calorimetry (DSC) according to JIS K7221. It is preferably 20 J / g or more, and more preferably 50 J / g or less. When it is 15 J / g or more, in addition to being able to more effectively exhibit heat resistance and releasability that can withstand heat press molding in a resin sealing step or the like, the dimensional change rate is also suppressed. Therefore, it is possible to prevent the occurrence of wrinkles. On the other hand, when the amount of heat for melting the crystal is 60 J / g or less, the release layer A has an appropriate hardness, so that sufficient followability to the mold of the film can be obtained in the resin sealing step or the like. There is no risk of film damage.

The release layer A may contain other resins in addition to the fluororesin, 4-methyl-1-pentene copolymer, and / or polystyrene-based 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. As described above, even when the release layer A contains a large amount of soft resin (for example, when the 4-methyl-1-pentene copolymer contains a large amount of olefins having 2 to 20 carbon atoms), the hardness is relatively relatively high. By further containing a high resin, the release layer A can be hardened, which is advantageous in suppressing the occurrence of wrinkles in the sealing step and the like.

The content of these other resins is preferably, for example, 3 to 30% by mass with respect to the resin components constituting the release layer A. By setting the content of the other resin to 3% by mass or more, the effect of the addition can be made substantial, and by setting the content to 30% by mass or less, the releasability to the mold or the molded product is maintained. be able to.

In addition to the fluororesin, 4-methyl-1-pentene (co) polymer, and / or polystyrene-based resin, the release layer A is a heat-resistant stabilizer and a weather-resistant stabilizer as long as the object of the present invention is not impaired. , Anti-rusting agents, anti-copper damage stabilizers, anti-static agents, and other known additives generally blended in film resins may 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-based resin.

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

The surface of the release layer A may have an uneven shape, if necessary, thereby improving the release property. The method of imparting unevenness to the surface of the release layer A is not particularly limited, but a general method such as embossing can be adopted.

Release layer A'
The release film for a process of the present invention may further 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 invention may be a process release film which is a laminated film containing the release layer A, the heat-resistant resin layer B, and the release layer A'in this order.
The contact angle of the release layer A'which may constitute the release film for the process of the present invention with water is 90 ° to 130 °, preferably 95 ° to 120 °, and more preferably 98 ° to 98 °. It is 115 °, more preferably 100 ° to 110 °. The preferable material, structure, physical properties, etc. of the release layer A'are the same as those described above for the release layer A.

When the release film for the process 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'are the same. It may be a layer of composition or a layer of different composition.
From the viewpoint of prevention of warpage and ease of handling due to having the same releasability on each surface, the release layer A and the release layer A'may have the same or substantially the same configuration. Preferably, from the viewpoint of optimally designing each in relation to the process using the release layer A and the release layer A', for example, the release layer A is made excellent in releasability from the mold, and the mold is released. From the viewpoint of making the layer A'excellent in peelability from the molded product, it is preferable that the release layer A and the release layer A'have different configurations.
When the release layer A and the release layer A'have different configurations, the release layer A and the release layer A'may be made of the same material but have different configurations such as thickness. However, the material and other configurations may be different.

Heat resistant resin layer B
The heat-resistant resin layer B constituting the release film for a process of the present invention has a function of supporting the release layer A (and, in some cases, the release layer A') and suppressing the generation of wrinkles due to the mold temperature or the like.
In the process release film of the present invention, the rate of change in thermal dimension from 23 ° C. to 120 ° C. in the lateral (TD) direction of the heat resistant resin layer B is 3% or less, or the lateral (TD) of the heat resistant resin layer B. ) The thermal dimensional change rate from 23 ° C. to 170 ° C. in the direction is preferably 3% or less. Further, the heat-resistant resin layer B has a thermal dimensional change rate of 3% or less from 23 ° C. to 120 ° C. in the lateral (TD) direction and a thermal dimensional change from 23 ° C. to 170 ° C. in the lateral (TD) direction. More preferably, the rate is 3% or less.
Any resin layer including a non-stretched film can be used as the heat-resistant resin layer B, but it is particularly preferable that the heat-resistant resin layer B contains a stretched film.
The stretched film tends to have a low coefficient of thermal expansion or a negative coefficient of thermal expansion due to the influence of stretching in the manufacturing process, and the rate of change in thermal dimension from 23 ° C. to 120 ° C. in the lateral (TD) direction is 3% or less. Alternatively, the heat-resistant resin layer B can be used as the heat-resistant resin layer B because it is relatively easy to realize the characteristic that the coefficient of thermal dimensional change from 23 ° C. to 170 ° C. in the lateral (TD) direction of the heat-resistant resin layer B is 3% or less. It can be preferably used.
The rate of change in thermal dimension from 23 ° C. to 120 ° C. in the lateral (TD) direction of the heat-resistant resin layer B is preferably 2% or less, more preferably 1.5% or less, and 1% or less. More preferably, on the other hand, it is preferably −10% or more.
The rate of change in thermal dimension from 23 ° C. to 170 ° C. in the lateral (TD) direction of the heat-resistant resin layer B is preferably 2% or less, more preferably 1.5% or less, and 1% or less. More preferably, on the other hand, it is preferably −10% or more.

The stretched film may be a uniaxially stretched film or a biaxially stretched film. In the case of a uniaxially stretched film, either longitudinal stretching or transverse stretching may be used, but it is desirable that the film is stretched at least in the lateral (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 the coefficient of thermal expansion in the lateral (TD) direction or to be negative by stretching, and their mechanical properties are suitable for the use of the present invention. Since it is low in cost and relatively easy to obtain, it is particularly suitable as a stretched film in the heat-resistant resin layer B.

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.
The polyamide constituting the stretched polyamide film is not particularly limited, but polyamide-6, polyamide-66 and the like can be preferably used.
As the stretched polypropylene film, a uniaxially stretched polypropylene film, a biaxially stretched polypropylene film and the like can be preferably used.
The draw ratio is not particularly limited, and an appropriate value may be appropriately set in order to appropriately control the thermal dimensional change rate and realize suitable mechanical properties. For example, in the case of a stretched polypropylene film, the longitudinal direction is used. The range is preferably 2.7 to 8.0 times in both the horizontal direction, and in the case of a stretched polypropylene film, the range is preferably 2.7 to 5.0 times in both the vertical direction and the horizontal direction. In the case of a polypropylene film, in the case of a biaxially stretched polypropylene film, the range is preferably 5.0 to 10.0 times in both the vertical direction and the horizontal direction, and in the case of a uniaxially stretched polypropylene film, 1. The range is preferably 5 to 10.0 times.

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 the rate of change in thermal dimensions within an appropriate range. Is preferable. 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 preferable, and it is more preferably 185 or more and 210 ° C. or lower, and particularly preferably 185 or more 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 contained in the heat-resistant resin layer B, for example, a crystalline resin such as a polyester resin, a polyamide resin, or a polypropylene resin can be used for a part or all of the crystalline resin. 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 crystal component of the crystalline resin in the heat-resistant resin layer B, wrinkles are less likely to occur in the resin sealing step or the like, and it is more advantageous to prevent wrinkles from being transferred to the molded product and causing poor appearance. Become.
The resin constituting the heat-resistant resin layer B preferably has a crystal melting heat of 20 J / g or more and 100 J / g or less in the first temperature raising step measured by differential scanning calorimetry (DSC) according to JIS K7221. 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, and more preferably 28 J / g or more and 50 J / g or less, 28 J / g or less. It is more preferably g or more and 40 J / g or less, and further preferably 28 J / g or more and 35 J / g or less. When it is 20 J / g or more, heat resistance and releasability that can withstand heat press molding in a resin sealing step or the like can be effectively exhibited, and the dimensional change rate can be slightly suppressed. , The occurrence of wrinkles can also be prevented. On the other hand, when the amount of heat of crystal melting is 100 J / g or less, it is possible to impart an appropriate hardness to the heat-resistant resin layer B, so that sufficient followability of the film to the mold is ensured in the resin sealing step or the like. In addition to being able to do this, there is no risk of the film being easily damaged. In the present embodiment, the calorific value of crystal melting is the calorific value (J / g) on the vertical axis and the calorific value (J / g) on the horizontal axis obtained in the first heating step in the measurement by differential scanning calorimetry (DSC) according to JIS K7221. In the chart showing the relationship with the temperature (° C.), it means a numerical value obtained by the sum of the peak areas having peaks 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 and stretching conditions during film production.

The thickness of the heat-resistant resin layer B is not particularly limited as long as the film strength can be secured, but is usually 1 to 1.
It is 00 μm, preferably 5 to 50 μm.

Other Layers The process release film of the present invention may have layers other than the release layer A, the heat-resistant resin layer B, and the release layer A'as long as it does not contradict the object of the present invention. For example, an adhesive layer may be provided between the release layer A (or the 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 peel off even in the resin sealing step or the mold release step.

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

The total thickness of the release film for a process of the present invention is not particularly limited, but is preferably 10 to 300 μm, more preferably 30 to 150 μm, for example. When the total thickness of the release film is within the above range, it is preferable because the handleability when used as a scroll is good and the amount of waste of the film is small.

Hereinafter, preferred embodiments of the process release film of the present invention will be described in more detail. FIG. 1 is a schematic view showing an example of a release film for a process having a three-layer structure. As shown in FIG. 1, the release film 10 has a heat-resistant resin layer 12 and a release layer 16 formed on one side thereof via an adhesive layer 14.

The release layer 16 is the above-mentioned release layer A, the heat-resistant resin layer 12 is the above-mentioned heat-resistant resin layer B, and the adhesive layer 14 is the above-mentioned adhesive layer. The release layer 16 is preferably arranged on the side in contact with the sealing resin in the sealing process; the heat resistant resin layer 12 is preferably arranged on the side in contact with the inner surface of the mold in the sealing process.

FIG. 2 is a schematic view showing an example of a release film for a process having a five-layer structure. Members having the same functions as those in FIG. 1 are designated by the same reference numerals. As shown in FIG. 2, the release film 20 has a heat-resistant resin layer 12, and a release layer 16A and a release layer 16B formed on both sides thereof via an adhesive layer 14. The release layer 16A is the above-mentioned release layer A, the heat-resistant resin layer 12 is the above-mentioned heat-resistant resin layer B, the release layer 16B is the above-mentioned release layer A', and the adhesive layer 14 is the above-mentioned above-mentioned, respectively. It is an adhesive layer.

The compositions of the release layers 16A and 16B may be the same or different from each other. The thicknesses of the release layers 16A and 16B may also be the same or different from each other. However, when the release layers 16A and 16B have the same composition and thickness, they have a symmetrical structure and the release film itself is less likely to warp, which is preferable. In particular, the release film of the present invention may be stressed by heating in the sealing process, so it is preferable to suppress warpage. When the release layers 16A and 16B are formed on both surfaces of the heat-resistant resin layer 12 as described above, it is preferable that good release properties can be obtained on both the molded product and the inner surface of the mold.

Method for Producing Release Film for Process The release film for process of the present invention can be produced by any method. For example, 1) a method of producing a release film for a process by co-extruding and laminating a release layer A and a heat-resistant resin layer B (co-extrusion forming method), and 2) on a film to be a heat-resistant resin layer B. A molten resin of the resin to be the release layer A or the adhesive layer is applied and dried, or a resin solution in which the resin to be the release layer A or the adhesive layer is dissolved in a solvent is applied and dried. A method for producing a release film for a process (coating method), 3) A film to be a release layer A and a film to be a heat-resistant resin layer B are produced in advance, and these films are laminated. There is a method (lamination method) for producing a release film for a process.

In the method of 3), as a method of laminating each resin film, various known laminating methods can be adopted, and examples thereof include an extrusion laminating method, a dry laminating method, and a thermal laminating method.
In the dry laminating method, each resin film is laminated using an adhesive. As the adhesive, a known adhesive for dry laminating can be used. For example, a polyvinyl acetate adhesive; a homopolymer or copolymer of an acrylic acid ester (ethyl acrylate, butyl acrylate, 2-ethylhexyl ester of acrylic acid, etc.), or an acrylic acid ester and another monomer (methacrylic acid). Polyacrylic acid ester-based adhesives composed of copolymers with methyl, acrylonitrile, styrene, etc.; cyanoacrylate-based adhesives; ethylene and other monomers (vinyl acetate, ethyl acrylate, acrylic acid, methacrylic acid) Ethylene copolymer adhesives made of copolymers with etc.); Cellulosic adhesives; Polyester adhesives; Polyamide adhesives; Polygonic adhesives; Amino resin adhesives made of urea resin or melamine resin, etc. Adhesives; Phenole resin-based adhesives; Epoxy-based adhesives; Polyurethane-based adhesives that crosslink polyols (polyether polyols, polyester polyols, etc.) with isocyanates and / or isocyanurates; Reactive (meth) acrylic adhesives Rubber-based adhesives made of chloroprene rubber, nitrile rubber, styrene-butadiene rubber, etc .; silicone-based adhesives; inorganic adhesives made of alkali metal silicate, low-melting point glass, etc .; other adhesives can be used. As the resin film to be laminated by the method of 3), a commercially available one may be used, or one manufactured by a known manufacturing 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 a known production method can be used.

1) The coextrusion molding method is preferable in that defects due to foreign matter getting caught between the resin layer to be the release layer A and the resin layer to be the heat-resistant resin layer B and warpage of the release film are unlikely to occur. .. 3) The laminating 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 at the interface between the films, if necessary. In order to enhance the adhesiveness between the films, the interface between the films may be subjected to a surface treatment such as a corona discharge treatment, if necessary.

The release film for process may be uniaxially or biaxially stretched as required, thereby increasing the film strength of the film.

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

Manufacturing Process The process release film of the present invention can be used by arranging 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 the resin is injected and molded. .. By using the process release film of the present invention, it is possible to effectively prevent mold release defects, burrs, etc. from the mold.
The resin used in the above manufacturing process may be either a thermoplastic resin or a thermosetting resin, but a thermosetting resin is widely used in the technical field, and an epoxy-based thermosetting resin is particularly used. It is preferable to use it.
The most typical manufacturing process is the encapsulation of a semiconductor chip, but the present invention is not limited to this, and the present invention can be applied to a fiber reinforced plastic molding process, a plastic lens molding process, and the like. ..

3, FIG. 4A and FIG. 4B are schematic views showing an example of a method for manufacturing a resin-sealed semiconductor using the release film of the present invention.
As shown in FIG. 3a, the release film 1 of the present invention is supplied from the roll-shaped roll into the molding die 2 by rolls 1-2 and 1-3. Next, the release film 1 is placed on the inner surface of the upper mold 2. If necessary, the inner surface of the upper mold 2 may be evacuated so that the release film 1 is brought into close contact with the inner surface of the upper mold 2. The semiconductor chip 6 arranged on the substrate is arranged in the lower mold 5 of the molding molding apparatus, and the sealing resin is arranged on the semiconductor chip 6 or the liquid sealing resin is covered with the semiconductor chip 6. The sealing resin 4 is accommodated between the upper mold 2 and the lower mold 5 on which the release film 1 that has been exhaust-sucked and adhered to the mold 1 is arranged. Next, as shown in FIG. 3b, the upper mold 2 and the lower mold 5 are closed with the mold release film 1 of the present invention, and the sealing resin 4 is cured.

As shown in FIG. 3c, the sealing resin 4 is fluidized in the mold by the mold closing and curing, and the sealing resin 4 flows into the space and is filled and sealed so as to surround the side surface of the semiconductor chip 6. The upper mold 2 and the lower mold 5 open the mold 6 and take out the chip 6. After opening the mold and taking out the molded product, the release film 1 is used repeatedly a plurality of times, or a new release film is supplied and subjected to the next resin molding molding.

The release film of the present invention is brought into close contact with the upper mold, interposed between the mold and the sealing resin, and resin molded to prevent the resin from adhering to the mold and stain the resin mold surface of the mold. And the molded product can be easily released from the mold.
The release film can be newly supplied and resin-molded for each resin molding operation, or can be newly supplied and resin-molded for each of a plurality of resin molding operations.

The sealing resin may be a liquid resin or a resin that is solid at room temperature, but a sealing material such as one that becomes liquid when the resin is sealed can be appropriately used. Specifically, as the sealing resin material, an epoxy-based resin (biphenyl-type epoxy resin, bisphenol epoxy resin, o-cresol novolac-type epoxy resin, etc.) is mainly used, and as a sealing resin other than the epoxy resin, a polyimide-based resin ( Bismaleimide-based), silicone-based resin (heat-curable addition type), and other resins normally used as sealing resins can be used. The resin sealing conditions vary depending on the sealing resin used, but may be appropriately set in the range of, for example, a curing temperature of 120 ° C. to 180 ° C., a molding pressure of 10 to 50 kg / cm ² , and a curing time of 1 to 60 minutes. it can.

The steps before and after the step of arranging the release film 1 on the inner surface of the molding die 8 and the step of arranging the semiconductor chip 6 in the molding die 8 are not particularly limited and may be performed at the same time, or the semiconductor chip 6 may be placed. After arranging, the release film 1 may be arranged, or after arranging the release film 1, the semiconductor chip 6 may be arranged.

As described above, since the release film 1 has the release layer A (and, if desired, the release layer A') having high releasability, the semiconductor package 4-2 can be easily released. Further, since the release film 1 has appropriate flexibility, it is excellent in followability to the mold shape, but is less likely to be wrinkled by the heat of the molding mold 8. Therefore, the sealed semiconductor package has a good appearance without wrinkles being transferred to the resin sealing surface of the sealed semiconductor package 4-2 or a portion not filled with the resin (resin chipping). 4-2 can be obtained.

Further, not limited to the compression molding method in which the solid sealing resin material 4 is pressurized and heated as shown in FIG. 3, a transfer molding method in which the sealing resin material in a fluid state is injected as described later is adopted. May be good.

4A and 4B are schematic views showing a transfer molding method which is an example of a method for manufacturing a resin-sealed semiconductor using the release film of the present invention.

As shown in FIG. 4A, the release film 22 of the present invention is supplied from the roll-shaped roll into the molding die 28 by the roll 24 and the roll 26 (step a). Next, the release film 22 is placed on the inner surface 30A of the upper mold 30 (step b). If necessary, the upper mold inner surface 30A may be evacuated to bring the release film 22 into close contact with the upper mold inner surface 30A. Next, the semiconductor chip 34 to be resin-sealed (semiconductor chip 34 fixed to the substrate 34A) is placed in the molding die 28, the sealing resin material 36 is set (step c), and the mold is fastened (step c). Step d).

Then, as shown in FIG. 4B, the sealing resin material 36 is injected into the molding die 28 under predetermined heating and pressurizing conditions (step e). The temperature (molding temperature) of the molding die 28 at this time is, for example, 165 to 185 ° C., the molding pressure is, for example, 7 to 12 MPa, and the molding time is, for example, about 90 seconds. Then, after holding for a certain period of time, the upper mold 30 and the lower mold 32 are opened, and the resin-sealed semiconductor package 40 and the release film 22 are simultaneously or sequentially released (step f).

Then, as shown in FIG. 5, a desired semiconductor package 44 can be obtained by removing the excess resin portion 42 from the obtained semiconductor package 40. The release film 22 may be used as it is for resin encapsulation of other semiconductor chips, but each time molding is completed, the roll is operated to feed the film, and the release film 22 is newly formed into a molding die. It is preferable to supply to 28.

The steps before and after the step of arranging the release film 22 on the inner surface of the molding die 28 and the step of arranging the semiconductor chip 34 in the molding die 28 are not particularly limited and may be performed at the same time, or the semiconductor chip 34 may be placed. After arranging, the release film 22 may be arranged, or after arranging the release film 22, the semiconductor chip 34 may be arranged.

As described above, since the release film 22 has the release layer A (and, if desired, the release layer A') having high releasability, the semiconductor package 40 can be easily released. Further, since the release film 22 has appropriate flexibility, it is excellent in followability to the mold shape, but is less likely to be wrinkled by the heat of the molding mold 28. Therefore, the semiconductor package 40 having a good appearance can be obtained without wrinkles being transferred to the resin sealing surface of the semiconductor package 40 or a portion (resin chipping) not filled with the resin.

The release film of the present invention is not limited to the process of sealing a semiconductor element with a resin, but is also a process of molding and releasing various molded products using a molding die, for example, a fiber-reinforced plastic molding and a mold release process, and a plastic lens molding. It can also be preferably used in a mold removal process and the like.

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

In the following Examples / Comparative Examples, the physical properties / characteristics were evaluated by the following method.
(Thermal dimensional change rate)
A film sample was cut into a length of 20 mm and a width of 4 mm in the longitudinal direction and the width direction of the film, respectively, and using TMA (thermomechanical analyzer, product name: Q400) manufactured by TA Instruments, the distance between chucks was 8 mm and 0.005 N. After holding at 23 ° C for 5 minutes under a load, raise the temperature from 23 ° C to 120 ° C at a heating rate of 10 ° C / min, measure the dimensional change in each direction, and change the dimensional by the following formula (1). The rate was calculated.

Thermal dimensional change rate (%) (23 → 120 ° C) = {[(L _2- L ₁ ) / L ₁ ] × 100}
... (1)
L ₁ : Sample length (mm) at 23 ° C.
L ₂ : Sample length (mm) at 120 ° C.

Similarly, the temperature was raised from 23 ° C. to 170 ° C. at a heating rate of 10 ° C./min, the dimensional change in each direction was measured, and the dimensional change rate was calculated by the following formula (2).

Thermal dimensional change rate (%) (23 → 170 ° C) = {[(L _3- L ₁ ) / L ₁ ] × 100}
... (2)
L ₁ : Sample length (mm) at 23 ° C.
L ₃ : Sample length (mm) at 170 ° C.

Contact angle with water (water contact angle)
The water contact angle on the surface of the release layer A was measured using a contact angle measuring device (FACECA-W, manufactured by Kyowa Interface Science) in accordance with JIS R 3 2 57.

(Melting point (Tm), heat of crystal fusion)
Using Q100 manufactured by TA Instruments as a differential scanning calorimeter (DSC), weigh about 5 mg of a polymer sample, and in accordance with JIS K7121, 25 inflow of nitrogen gas: 50 ml / min. The heat melting curve was measured by raising the temperature from ° C. to 280 ° C. at a heating rate of 10 ° C./min, and the melting point (Tm) of the sample and the amount of heat of crystal melting were determined from the obtained heat melting curve.

(Releasability)
As shown in FIG. 3, the release film for the process produced in each Example / Comparative Example was placed between the upper mold and the lower mold with a tension of 10 N applied, and then the upper mold was parted. It was vacuum-adsorbed on the surface. Next, after filling the substrate with the sealing resin so as to cover the semiconductor chip, the semiconductor chip fixed to the substrate was placed in the lower mold and molded. At this time, the temperature of the molding die (molding temperature) was 120 ° C., the molding pressure was 10 MPa, and the molding time was 400 seconds. Then, as shown in FIG. 3c, the semiconductor chip was sealed with a sealing resin, and then 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 peels off naturally when the mold is opened.
Δ: The release film does not peel off naturally, but it easily peels off when pulled by hand (when tension is applied).
X: The release film is in close contact with the resin sealing surface of the semiconductor package and cannot be peeled off by hand.

(wrinkle)
The state of wrinkles on the release film and the resin-sealed surface of the semiconductor package after the release in the above step was evaluated according to the following criteria.
◯: There are no wrinkles on either the release film or the semiconductor package.
Δ: There are slight wrinkles on the release film, but there is no wrinkle transfer to the semiconductor package.
×: There are many wrinkles on the semiconductor package as well as the release film.

(Mold followability)
The mold followability of the release film when the mold was released in the above step was evaluated according to the following criteria.
◯: There is no resin chipping (the part where the resin is not filled) in the semiconductor package.
Δ: There is a slight resin chipping at the end of the semiconductor package (however, chipping due to wrinkles is excluded) ×: There are many resin chips at the edge of the semiconductor package (however, chipping due to wrinkles is excluded)

[Example 1]
As the heat-resistant resin layer B, a biaxially stretched PET (polyethylene terephthalate) film having a film thickness of 16 μm (manufactured by Toray Industries, Inc., product name: Lumirror F865) was used. The rate of change in thermal dimensions of the biaxially stretched PET film from 23 ° C. to 120 ° C. was −1.6% in the longitudinal (MD) direction and −1.2% in the lateral (TD) direction. The melting point of the biaxially stretched PET film was 187 ° C., and the amount of heat of crystal melting was 30.6 J / g.

Unstretched 4-methyl-1-pentene copolymer resin film was used as the release layers A and A'. Specifically, "4-methyl-1-pentene copolymer resin (product name: TPX, brand name: MX022)" manufactured by Mitsui Chemicals, Inc. is melt-extruded at 270 ° C. to adjust the slit width of the T-type die. As a result, a non-stretched film having a thickness of 15 μm was used.
The unstretched 4-methyl-1-pentene copolymer resin film has improved adhesiveness with an adhesive so that when one film surface has a water contact angle of 30 ° or more based on JIS R3257, it becomes 30 or less. Corona treatment was applied from the viewpoint.
The thermal dimensional change rate of the 4-methyl-1-pentene copolymer resin film from 23 ° C. to 120 ° C. was 6.5% in the vertical (MD) direction and 3.1% in the horizontal (TD) direction. ..

(adhesive)
The following urethane-based adhesive A was used as the adhesive used in the dry laminating step of laminating the films.
[Urethane adhesive A]
Main agent: Takelac A-616 (manufactured by Mitsui Chemicals, Inc.). Hardener: Takenate 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.

(Manufacturing of release film)
One surface of a biaxially stretched PET (polyethylene terephthalate) film is coated with a urethane adhesive A at 1.5 g / m ² with a gravure coat to form a non-stretched 4-methyl-1-pentene copolymer resin film. After laminating the corona-treated surface with dry laminate, the urethane-based adhesive A was subsequently applied to the side of the biaxially stretched PET (polyethylene terephthalate) film surface of this laminated film at 1.5 g / m ² , and nothing was applied. The corona-treated surfaces of the stretched 4-methyl-1-pentene copolymer resin film are laminated by dry lamination to form a five-layer structure (separation layer A / adhesive layer / heat-resistant resin layer B / adhesive layer / release layer A). ') Process release film was obtained.
The dry laminating conditions were a substrate width of 900 mm, a transport speed of 30 m / min, a drying temperature of 50 to 60 ° C., a laminating roll temperature of 50 ° C., and a roll pressure of 3.0 MPa.

The rate of change in thermal dimensions of the release film for the process from 23 ° C. to 120 ° C. was 2.1% in the vertical (MD) direction and 1.5% in the horizontal (TD) direction.
Table 1 shows the evaluation results of mold releasability, wrinkles, and mold followability. The release film shows good releasability that peels off naturally when the mold is opened, and there are no wrinkles in either the release film or the semiconductor package, that is, wrinkles are sufficiently suppressed, and the semiconductor package lacks resin. It showed good mold followability without any. That is, the process release film of Example 1 was a process release film having good releasability, wrinkle suppression, and mold followability.

[Examples 2 to 12]
A release film for a process was prepared and sealed in the same manner as in Example 1 except that the films shown in Table 1 were used as the release layers A and A'and the heat-resistant resin layer B in the combinations shown in Table 1. The mold was released and the characteristics were evaluated. The results are shown in Table 1.
In some cases, wrinkle suppression or mold followability was not as good as in Example 1, but in each example, mold releasability, wrinkle suppression, and mold followability were balanced at a high level. It was a good release film for the process

The details of each film described in the table are as follows.
(A1) Unstretched 4MP-1 (TPX) film A non-stretched film with a thickness of 15 μm is formed using a 4-methyl-1-pentene copolymer resin (product name: TPX, brand name: MX022) manufactured by Mitsui Chemicals, Inc. What I did. (Melting point: 229 ° C., heat of crystal fusion: 21.7 J / g)
(A2) Unstretched 4MP-1 (TPX) film A non-stretched film having a thickness of 15 μm is formed using a 4-methyl-1-pentene copolymer resin (product name: TPX, brand name: DX818) manufactured by Mitsui Chemicals, Inc. What I did. (Melting point: 235 ° C., heat of crystal fusion: 28.1 J / g)
(A3) Non-stretched 4MP-1 (TPX) film A non-stretched film having a thickness of 50 μm is formed using a 4-methyl-1-pentene copolymer resin (product name: TPX, brand name: MX022) manufactured by Mitsui Chemicals, Inc. What I did. (Melting point: 229 ° C., heat of crystal fusion: 21.7 J / g)
(A4) Non-stretched 4MP-1 (TPX) film A non-stretched film having a thickness of 50 μm is formed using a 4-methyl-1-pentene copolymer resin (product name: TPX, brand name: DX818) manufactured by Mitsui Chemicals, Inc. What I did. (Melting point: 235 ° C., heat of crystal fusion: 28.1 J / g)
(A5) Fluororesin film ETFE (ethylene-tetrafluoroethylene) film with a thickness of 25 μm (manufactured by Asahi Glass Co., Ltd., product name: Aflex 25N) (melting point: 256 ° C., heat of crystal fusion: 33.7 J / g)
(A6) Polystyrene-based resin film Polystyrene-based film with a thickness of 50 μm (manufactured by Kurashiki Spinning Co., Ltd., product name: Oydis CA-F) (melting point: 253 ° C., heat of crystal melting: 19.2 J / g)
(B1) Biaxially stretched PET film Biaxially stretched PET (polyethylene terephthalate) film with a thickness of 16 μm (manufactured by Toray Co., Ltd., product name: Lumirror F865) (melting point: 187 ° C., heat of crystal fusion: 30.6 J / g)
(B2) Biaxially stretched PET film Biaxially stretched PET (polyethylene terephthalate) film with a thickness of 12 μm (manufactured by Toray Co., Ltd., product name: Lumirror S10) (melting point: 258 ° C., heat of crystal fusion: 39.4 J / g)
(B3) Biaxially stretched nylon film Biaxially stretched nylon film with a thickness of 15 μm (manufactured by Kohjin Film & Chemicals Co., Ltd., product name: Bonil RX) (melting point: 212 ° C., heat of crystal fusion: 53.1 J / g)
(B4) Biaxially stretched nylon film Biaxially stretched nylon film with a thickness of 15 μm (manufactured by Idemitsu Unitech Co., Ltd., product name: Unilon S330) (melting point: 221 ° C., heat of crystal melting: 60.3 J / g)
(B5) Biaxially stretched polypropylene film Biaxially stretched polypropylene film with a thickness of 20 μm (manufactured by Mitsui Chemicals Tohcello Co., Ltd., product name: U-2) (melting point: 160 ° C., heat of crystal melting: 93.3 J / g)
(B6) Non-stretched nylon film Non-stretched nylon film with a thickness of 20 μm (manufactured by Mitsubishi Resin Co., Ltd., product name: Dynamilon C) (melting point: 220 ° C., heat of crystal melting: 39.4 J / g)
(B7) Biaxially stretched PET film Biaxially stretched PET film with a thickness of 25 μm (manufactured by Teijin DuPont Film Co., Ltd., product name: FT3PE) (melting point: 214 ° C., heat of crystal melting: 40.3 J / g)
(B8) Non-stretched polybutylene terephthalate film A film formed of a non-stretched film having a thickness of 20 μm using a polybutylene terephthalate resin (brand name: 5020) manufactured by Mitsubishi Engineering Plastics Co., Ltd. (Melting point: 223 ° C., heat of crystal fusion: 49.8 J / g)
(B9) Non-stretched polybutylene terephthalate film A film formed of a non-stretched film having a thickness of 20 μm using a polybutylene terephthalate resin (brand name: 5505S) manufactured by Mitsubishi Engineering Plastics Co., Ltd. (Melting point: 219 ° C., heat of crystal fusion: 48.3 J / g)
(B10) Non-stretched polybutylene terephthalate film A non-stretched film having a thickness of 50 μm is formed using a polybutylene terephthalate resin (brand name: 5020) manufactured by Mitsubishi Engineering Plastics Co., Ltd. (Melting point: 223 ° C., heat of crystal fusion: 49.8 J / g)
(B11) Non-stretched polybutylene terephthalate film A non-stretched film having a thickness of 50 μm is formed using a polybutylene terephthalate resin (brand name: 5505S) manufactured by Mitsubishi Engineering Plastics Co., Ltd. (Melting point: 219 ° C., heat of crystal fusion: 48.3 J / g)

[Comparative Examples 1 to 4]
The films A3, A4, B10, and B11 shown in Table 1 are used independently as a release film for a process, and sealed and released in the same manner as in Example 1, and the characteristics of the release film for a process are obtained. Was evaluated.
In each of the comparative examples, the performance was generally inferior to that of the examples, and the occurrence of wrinkles could not be suppressed in particular.

[Examples 13 to 20]
Using the release films in which the films shown in Table 2 were the release layers A and A'and the heat-resistant resin layer B in the combination shown in Table 2, a release film for a process was prepared in the same manner as in Example 1. Sealing and mold release were performed, and the characteristics were evaluated.
As shown in FIG. 4, the release film was placed between the upper mold and the lower mold with a tension of 20 N applied, and then vacuum-adsorbed on the parting surface of the upper mold. Next, after filling the substrate with the sealing resin so as to cover the semiconductor chip, the semiconductor chip fixed to the substrate was placed in the lower mold and molded. At this time, the temperature of the molding die (molding temperature) was 170 ° C., the molding pressure was 10 MPa, and the molding time was 100 seconds. Then, as shown in FIG. 3c, the semiconductor chip was sealed with a sealing resin, and then the resin-sealed semiconductor chip (semiconductor package) was released from the release film. The results are shown in Table 2.
In some cases, the mold followability was not as good as in Example 1, but in all the examples, the mold releasability, wrinkle suppression, and mold followability were well balanced for a good process release. Mold films, and in particular, Examples 11 and 13 to 15 were process release films having good mold releasability, wrinkle suppression, and mold followability.

[Comparative Examples 5 to 7]
Process release films were prepared in the same manner as in Examples 11 to 16 except that the films shown in Table 2 were used as the release layers A and A'and the heat-resistant resin layer B in the combinations shown in Table 2. Sealing and mold release were performed, and the characteristics were evaluated. The results are shown in Table 2.
The mold releasability and mold followability were good as in the examples, but the occurrence of wrinkles could not be suppressed.

[Comparative Examples 8 to 11]
The films A1, A2, B10, and B11 shown in Table 2 are used independently as a release film for a process, and are sealed and released in the same manner as in Examples 11 to 16 to release a release film for a process. The characteristics of the film were evaluated.
In each of the comparative examples, the performance was generally inferior to that of each example, and the occurrence of wrinkles could not be suppressed in particular.

The process release film of the present invention has a high level of releasability, wrinkle suppression, and mold followability that could not be realized by the prior art. Therefore, by using this, a semiconductor chip or the like is sealed with a resin. It brings about a technical effect having high practical value that the molded product obtained by the above can be easily released from the mold and the molded product without appearance defects such as wrinkles and chips can be manufactured with high productivity. It has high utility in each field of industry including the semiconductor process industry.
Further, the process release film of the present invention can be used not only for semiconductor packages but also for various mold moldings in fiber-reinforced plastic molding processes, plastic lens molding processes, etc., and thus mold molding other than the semiconductor industry. It also has high utility in each field of the industry.

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 10, 20, 22: Release film 12: Heat-resistant resin layer B
14: Adhesive layers 16, 16A: Release layer A
16B: Release layer A'
24, 26: Roll 28: Molding mold 30: Upper mold 32: Lower mold 34: Semiconductor chip 34A: Substrate 36: Encapsulating resin 40, 44: Semiconductor package

Claims (19)

A release film for a process, which is a laminated film containing a release layer A and a heat-resistant resin layer B.
The contact angle of the release layer A with water is 90 ° to 130 °.
The release film for a process, wherein the rate of change in thermal dimension from 23 ° C. to 120 ° C. in the lateral (TD) direction of the laminated film is 3% or less. The claim that the sum of the thermal dimensional change rate from 23 ° C. to 120 ° C. in the lateral (TD) direction and the thermal dimensional change rate from 23 ° C. to 120 ° C. in the longitudinal (MD) direction of the laminated film is 6% or less. The release film for a process according to 1. A release film for a process, which is a laminated film containing a release layer A and a heat-resistant resin layer B.
The contact angle of the release layer A with water is 90 ° to 130 °.
The release film for a process, wherein the rate of change in thermal dimension from 23 ° C. to 170 ° C. in the lateral (TD) direction of the laminated film is 4% or less. The claim that the sum of the thermal dimensional change rate from 23 ° C. to 170 ° C. in the lateral (TD) direction and the thermal dimensional change rate from 23 ° C. to 170 ° C. in the longitudinal (MD) direction of the laminated film is 7% or less. The release film for a process according to 3. The release film for a process according to any one of claims 1 to 4, wherein the heat-resistant resin layer B has a thermal dimensional change rate of 3% or less from 23 ° C. to 120 ° C. in the lateral (TD) direction. The sum of the thermal dimensional change rate from 23 ° C. to 120 ° C. in the lateral (TD) direction and the thermal dimensional change rate from 23 ° C. to 120 ° C. in the longitudinal (MD) direction of the heat-resistant resin layer B is 6% or less. The release film for a process according to claim 5. The release film for a process according to any one of claims 1 to 4, wherein the heat-resistant resin layer B has a thermal dimensional change rate of 3% or less from 23 ° C. to 170 ° C. in the lateral (TD) direction. The sum of the thermal dimensional change rate from 23 ° C. to 170 ° C. in the lateral (TD) direction and the thermal dimensional change rate from 23 ° C. to 120 ° C. in the longitudinal (MD) direction of the heat-resistant resin layer B is 4% or less. The release film for a process according to claim 7. The release layer A according to any one of claims 1 to 8, wherein the release layer A contains a resin selected from the group consisting of a fluororesin, a 4-methyl-1-pentene (co) polymer, and a polystyrene-based resin. Release film for process. The process release film according to any one of claims 1 to 9, wherein the heat-resistant resin layer B includes a stretched film. The release film for a process according to claim 10, wherein the stretched film is selected from the group consisting of a stretched polyester film, a stretched polyamide film, and a stretched polypropylene film. Any of claims 1 to 11, wherein the heat-resistant resin layer B has a crystal melting heat of 15 J / g or more and 60 J / g or less in the first temperature raising step measured by differential scanning calorimetry (DSC) according to JIS K7221. The release film for the process according to paragraph 1. The laminated film further has a release layer A', and includes the release layer A, the heat-resistant resin layer B, and the release layer A'in this order.
The process release film according to any one of claims 1 to 12, wherein the release layer A'has a contact angle with water of 90 ° to 130 °. 13. Claim 13 that at least one of the release layer A and the release layer A'contains a resin selected from the group consisting of a fluororesin, a 4-methyl-1-pentene (co) polymer, and a polystyrene-based resin. Release film for the process described in. The process release film according to any one of claims 1 to 14, which is used in a sealing process using a thermosetting resin. The process release film according to any one of claims 1 to 15, which is used in a semiconductor encapsulation process. The process release film according to any one of claims 1 to 15, which is used in a fiber reinforced plastic molding process or a plastic lens molding process. A method for manufacturing resin-sealed semiconductors.
The process of arranging the resin-sealed semiconductor device at a predetermined position in the molding die,
A step of arranging the release film for the semiconductor encapsulation process according to any one of claims 1 to 14 on the inner surface of the molding die so that the release layer A faces the semiconductor device.
A step of injecting and molding a sealing resin between the semiconductor device and the release film for the semiconductor sealing process after molding the molding die.
The above-mentioned method for manufacturing a resin-sealed semiconductor. A method for manufacturing resin-sealed semiconductors.
The process of arranging the resin-sealed semiconductor device at a predetermined position in the molding die,
A step of arranging the release film for the semiconductor encapsulation process according to claim 13 or 14 on the inner surface of the molding die so that the release layer A'is opposed to the semiconductor device.
A step of injecting and molding a sealing resin between the semiconductor device and the release film for the semiconductor sealing process after molding the molding die.
The above-mentioned method for manufacturing a resin-sealed semiconductor.