JP6126446B2 - Release film and method for producing LED element sealing body - Google Patents

Description

  The present invention relates to a release film and a method for producing a semiconductor element encapsulant.

  The semiconductor device usually includes a substrate and a semiconductor element such as an LED chip mounted thereon, and can be a sealing body in which these are sealed with a sealing resin. Such a sealing body is manufactured by, for example, placing a semiconductor element mounted on a substrate in a mold; injecting a sealing resin into the mold and curing. And in order to make it easy to peel the sealing body obtained by hardening molding from a metal mold | die, the method of arrange | positioning a release film on the metal mold | die inner surface is taken (for example, patent document 1).

  As a release film used for resin sealing of LED and the like, a polyester resin film having a polysiloxane coating layer (Patent Document 1) and a film made of a thermoplastic elastomer composition mainly composed of a polyurethane elastomer (patent) Document 2) has been proposed. Moreover, as a release film used for resin sealing such as a printed wiring board, a release film containing a crystalline aromatic polyester resin as a matrix and having a heat of crystal fusion adjusted to a certain level (Patent Document 3), A release film (Patent Document 4), which is made of a mixed resin of a crystalline aromatic polyester not containing a polyether skeleton and a polyester containing a polyether skeleton and whose crystal heat of fusion is adjusted to a certain level or more has been proposed. .

JP 2010-245477 A JP 2012-206490 A Japanese Patent No. 4436803 Japanese Patent No. 4391725

  By the way, the mold used for resin sealing of the LED has a gap (from the parting surface of the upper mold and the lower mold to the deepest part of the cavity as compared with the mold used for resin sealing of a normal semiconductor element. The step is large and the shape is often complicated. Therefore, the release film used for LED resin sealing is required to be able to follow a complicated mold shape without tearing or wrinkling (having high mold followability). .

  However, since the film of Patent Document 1 has at least a two-layer structure, the film thickness tends to increase. Moreover, in order to obtain sufficient mechanical strength, the film of Patent Document 2 has to have a large film thickness. Therefore, the films of Patent Documents 1 and 2 may not have sufficient followability to the mold. Since the films of Patent Documents 3 and 4 have a high amount of heat of crystal melting, there is a possibility that followability to the mold shape is not sufficient.

  In addition, in order to obtain an LED encapsulant with high dimensional accuracy and a smooth surface, it is also required that the release film has high releasability.

  The present invention has been made in view of the above circumstances, and has good mold following ability and good mold releasability capable of following a complicated-shaped mold without causing breakage or wrinkles. It aims at providing a release film.

[1] A polyester resin layer containing polybutylene terephthalate disposed on at least one outermost layer, and the crystallinity of the polyester resin layer measured by wide angle X-ray diffraction (XRD) is 15% or more and 25 % In the FT-IR spectrum obtained by measuring the outermost layer of the polyester resin layer by the ATR method using Ge as an ATR crystal and an infrared light incident angle of 60 °, 2910 cm ^{−1 to} 2930 cm ^A release film that satisfies the relationship of the following formula (1), where Pa is the maximum absorption peak intensity in the region of ⁻¹ or less and Pb is the maximum absorption peak intensity in the region of 2950 cm ⁻¹ or more and 2970 cm ⁻¹ or less.
0.6 ≦ Pa / Pb ≦ 2.0 Formula (1)
[2] The release film according to [1], which is used for resin sealing of a semiconductor element.
[3] The release film according to [1] or [2], wherein the sealing resin used for the resin sealing is a silicone resin.
[4] The release film according to [2] or [3], wherein the semiconductor element is a light emitting element or a light receiving element.
[5] The release film according to [4], wherein the light-emitting element is an LED element.
[6] The release film according to any one of [1] to [5], which is a single layer film of a polyester resin layer containing the polybutylene terephthalate.

[7] A step of disposing the release film according to any one of [1] to [6] on the inner surface of the mold, a step of disposing a substrate on which a semiconductor element is mounted in the mold, and the mold Filling a mold with a sealing resin, clamping the mold, curing the sealing resin to obtain a semiconductor element sealing body, and peeling the release film from the semiconductor element sealing body. A method for manufacturing a sealed semiconductor element.
[8] The encapsulated semiconductor element according to [7], wherein the release film is disposed on the inner surface of the mold so that a polyester resin layer containing polybutylene terephthalate of the release film faces the semiconductor element. Manufacturing method.
[9] The method for manufacturing a sealed semiconductor element according to [7] or [8], wherein the sealing resin is a silicone resin.
[10] The method for producing a sealed semiconductor element according to any one of [7] to [9], wherein the semiconductor element is a light emitting element or a light receiving element.

  ADVANTAGE OF THE INVENTION According to this invention, it can provide the mold release film which has favorable followable | trackability also to the metal mold | die of a complicated shape, and has favorable mold release property.

It is a figure which shows an example of the ATR-IR spectrum of the release film of this invention. It is a figure which shows an example of the diffraction profile of the out-of-plane (out-of-plane direction) obtained by GIWAXS measurement of the release film of this invention. It is a schematic diagram which shows the example of a part of manufacturing apparatus of a film. It is a schematic diagram which shows an example of the manufacturing process of the sealing body of LED. It is a schematic diagram which shows an example of the manufacturing process of the sealing body of LED. It is a schematic diagram which shows an example of the manufacturing process of the sealing body of LED. It is a schematic diagram which shows an example of the manufacturing process of the sealing body of LED. It is a schematic diagram which shows an example of the manufacturing process of the sealing body of LED. It is a schematic diagram which shows an example of the manufacturing process of the sealing body of LED in an Example. It is a schematic diagram which shows an example of the manufacturing process of the sealing body of LED in an Example. It is a schematic diagram which shows an example of the manufacturing process of the sealing body of LED in an Example. It is a schematic diagram which shows an example of the manufacturing process of the sealing body of LED in an Example. It is a schematic diagram which shows an example of the manufacturing process of the sealing body of LED in an Example.

1. Release Film The release film of the present invention includes a polyester resin layer disposed on at least one outermost layer.

About the polyester resin layer The polyester resin layer is disposed on at least one outermost layer of the release film and functions as the release layer A. The polyester resin layer preferably contains polybutylene terephthalate because it has high crystallinity and heat resistance.

  The intrinsic viscosity of the polybutylene terephthalate is preferably 1.0 to 1.5 in order to make the mechanical strength of the polyester resin layer a certain level or more and to ensure melt moldability. 2 is more preferable. The intrinsic viscosity can be measured at 25 ° C. based on JIS K 7367-5.

  The melting point of polybutylene terephthalate is preferably 200 to 245 ° C. from the viewpoint of obtaining heat resistance and moldability that are above a certain level. The melting point can be measured as an endothermic peak temperature at the time of melting detected when the temperature is increased at a rate of temperature increase of 20 ° C./min using a differential scanning calorimeter (manufactured by Mac Science, DSC3100S). The lower limit of the melting point is preferably 210 ° C. If the melting point is less than 200 ° C., sufficient heat resistance may not be obtained.

  Examples of commercially available products of polybutylene terephthalate include NOVADURAN 5020, 5010CS, 5510S or 5505S manufactured by Mitsubishi Engineering Plastics Co., Ltd., Juranex manufactured by Polyplastics Co., Ltd., and Toraycon manufactured by Toray Industries, Inc.

  The polyester resin layer may further contain other resins and additives as long as the effects of the present invention are not impaired. Examples of other resins include polyester resins other than polybutylene terephthalate (for example, polyester resins obtained by reacting aliphatic diols other than 1,4-butanediol with aromatic dicarboxylic acids such as terephthalic acid) and polyester elastomers. (For example, polybutylene terephthalate elastomer) and the like, preferably polybutylene terephthalate elastomer and polyethylene terephthalate.

  Examples of additives include heat stabilizers, weathering stabilizers, rust inhibitors, copper damage stabilizers, antistatic agents, inorganic fillers, flame retardants, UV absorbers, fibers, inorganic substances, higher fatty acid salts, etc. included.

  The content of polybutylene terephthalate is preferably 60% by mass or more, more preferably 80% by mass or more, and further preferably 100% by mass with respect to the polyester resin layer. By setting the content of polybutylene terephthalate to a certain level or more, it is easy to obtain a polyester resin layer having high followability and releasability while having heat resistance.

  The release film may be a single layer film composed of a polyester resin layer; or a laminated film including a polyester resin layer and other layers. The polyester resin layer contained in the laminated film is disposed on at least one outermost layer of the release film; preferably on the outermost layer on the side in contact with the sealing body of the molded product (for example, a semiconductor element) of the release film. Other layers included in the laminated film may be a base material layer C, an adhesive layer B, or the like.

  Examples of the resin constituting the base layer C include polycarbonate resin, polyester resin other than polybutylene terephthalate, polyamide resin, polyolefin resin, and cyclic polyolefin to increase the mechanical strength and heat resistance of the release film. Resin, polyurethane resin and the like are included. Among these, a resin having good heat resistance or good adhesion to the release layer A is preferable, and a polyester resin other than polyamide resin or polybutylene terephthalate is preferable.

  The storage elastic modulus E ′ at 120 ° C. of the base material layer C can be set to 15 MPa or more and 1000 MPa or less, for example, in order to sufficiently increase the mechanical strength of the release film.

  The adhesive layer B can be made of an adhesive resin. The adhesive resin preferably contains a resin that is easily compatible with both the polyester resin layer (release layer A) and the base material layer C. Specific examples of the adhesive resin include a modified 4-methyl-1-pentene polymer graft-modified with an unsaturated carboxylic acid and / or an acid anhydride of an unsaturated carboxylic acid, the modified 4-methyl- Examples thereof include a mixture containing a 1-pentene polymer and an α-olefin polymer, and a polyolefin elastomer.

  The thickness of the adhesive layer is not particularly limited as long as it can improve the adhesiveness between the polyester resin layer and the base material layer C, but is usually about 4 to 6 μm.

  Similar to the polyester resin layer, the adhesive layer B and the base material layer C may further include the above-described additives in addition to the main component.

Examples of the laminated structure when the release film of the present invention is a laminated film including a polyester resin layer and other layers include the following. In the following, A represents the release layer A; B represents the adhesive layer B; C represents the substrate layer C; A ′ represents the other release layer A ′. The release layer A corresponds to the above-described polyester resin layer. When the release film of the present invention is a laminated film, it is preferable to have a symmetric laminated structure with respect to the center layer. This is because the release film having a symmetric laminated structure is less likely to be deformed (warped or the like) due to a difference in thermal expansion or moisture absorption when heated in a mold. The other release layer A ′ may be the same as or different from the release layer A. However, from the viewpoint of difficulty in deformation and followability of the mold shape, the other release layer A ′ is The material is the same as that of the release layer A. In particular, the degree of crystallinity of the other release layer A ′ is preferably 15% or more and 25% or less in the same manner as the release layer A, from the viewpoint of the followability of the mold shape.
A / C
A / C / A '
A / B / C
A / B / C / B / A '

  In particular, the mold release film is a single-layer film composed of a polyester resin layer because it has not only good mold followability and mold releasability, but also good heat resistance and can simplify the manufacturing process. Is preferred.

  The thickness of the release film is preferably 20 to 100 μm, and more preferably 40 to 60 μm. By setting the thickness of the release film to a certain value or more, the mechanical strength of the film can be increased. On the other hand, by setting the thickness of the release film to a certain value or less, good followability can be easily obtained even for a complicatedly shaped mold.

  In order to allow the release film of the present invention to follow well with a mold having a complicated shape such as used for LED resin sealing, for example, a polyester resin layer disposed on the outermost layer of the release film It is preferable to lower the crystallinity of. A film having a low degree of crystallinity is considered to have moderate flexibility. When it has an appropriate flexibility, the mold following ability is improved. Therefore, the crystallinity of the layer provided on the outermost layer of the release film affects the mold followability. Specifically, the crystallinity of the polyester resin layer of the present invention is preferably 15% or more and 25% or less, and more preferably 18% or more and 23% or less.

The crystallinity of the release film can be measured by the wide angle X-ray diffraction method (XRD) under the following conditions.
(Measurement equipment and measurement conditions)
Apparatus: RINT2500 manufactured by Rigaku Corporation
Output: 50kV-300mA
Target: Cu (CuKα)
Optical system: Parallel beam method optical system Measurement speed: 2 ° / min
Angular measuring range: 2θ = 5-35 °
From the integrated intensity of the peak at a diffraction angle of 2θ = 7 to 35 ° at which diffraction peaks of both the amorphous part and the crystalline part of the resin appear, the crystallinity (%) is calculated by the following formula (2). .
Crystallinity (χc) = (Integral intensity of crystalline part (peaks near 2θ = 16 °, 17 °, 20 °, 23 °, 25 °) / part containing amorphous and crystalline (2θ = 7) Integral intensity of ˜35 °) × 100 (%) Expression (2)

  When the release film is a single layer film made of a polyester resin layer, the release film may be used as a measurement sample as it is. On the other hand, when the release film is a laminated film including a polyester resin layer and other layers, a sample obtained by peeling or cutting the polyester resin layer may be used as a measurement sample. When cutting out the measurement sample, it is not necessary to cut out the entire thickness direction of the polyester resin layer, and it is sufficient to cut out a range in the thickness direction to the extent that reproducibility is obtained.

  The crystallinity of the polyester resin layer can be adjusted mainly by the temperature of the cast roll during film formation. In order to reduce the crystallinity, it is preferable to lower the temperature of the cast roll, for example.

On the other hand, when the crystallinity of the polyester resin layer is lowered, the flexibility of the film surface is increased, so that the releasability is likely to be lowered. In contrast, the inventors of the present invention have an absorption in the region of 2910 cm ⁻¹ or more and 2930 cm ⁻¹ or less in the FT-IR spectrum (ATR-IR spectrum) obtained by ATR measurement of the surface of the polyester resin layer of the release film. It has been found that the releasability is enhanced when the intensity of the peak is above a certain level.

Absorption peak of 2910cm ^-1 or 2930 cm ^-1 The following region is from a methylene chain (alkylene chain) constituting the main chain of polybutylene terephthalate. Therefore, the intensity of the absorption peak in the region of 2910 cm ⁻¹ or more and 2930 cm ⁻¹ or less is greater than or equal to a certain level, which means that the alkylene chain (nonpolar site) of polybutylene terephthalate is exposed (oriented) on the surface of the polyester resin layer. It is thought that it shows. That is, it has been found that the release property of the release film can be enhanced by exposing (orienting) the alkylene chain (nonpolar site) of polybutylene terephthalate on the surface of the polyester resin layer.

Specifically, in the FT-IR spectrum (ATR-IR spectrum) measured by the ATR method on the outermost layer of the polyester resin layer, the maximum absorption peak intensity (maximum absorption) in the region of 2910 cm ^{−1 to} 2930 cm ^−1. when the peak intensity) Pa, the maximum value of the absorption peak intensity of 2950 cm ^-1 or 2970cm ^-1 following areas (maximum absorption peak intensity) was Pb, it is preferable to satisfy the relation of the following formula (1).
0.6 ≦ Pa / Pb ≦ 2.0 Formula (1)

  Further, Pa / Pb is more preferably in the range of 0.7 to 1.2.

  The ATR-IR spectrum is measured using a Fourier transform infrared spectrophotometer (FT-IR8300, manufactured by JASCO Corporation), with the ATR crystal being Ge and the infrared light incident angle θ being 60 °. Can be obtained.

FIG. 1 is a diagram showing an example of an ATR-IR spectrum of the release film of the present invention. As shown in FIG. 1, 2910cm ^-1 or 2930 cm ^-1 following areas in the absorption peak a is confirmed, the absorption peak b is confirmed in the following regions 2950 cm ^-1 or 2970cm ^-1. The intensity of the absorption peak in each wavelength region can be obtained by reading the maximum value of the absorption peak height with respect to the baseline. Baseline, the line connecting the flat portion in the vicinity of 3050 cm ^-1 and near 2750 cm ^-1 (see Figure 1).

  The peak intensity ratio Pa / Pb in the ATR-IR spectrum; that is, the proportion of the alkylene chain of the polybutylene terephthalate exposed on the surface of the polyester resin layer is mainly the adhesion strength and adhesion time between the melt and the cast roll during film formation. Can be adjusted.

For example, if the melt is too close to the cast roll, it will be overcooled and the surface energy of the melt will not be sufficiently relaxed. As a result, polar sites such as C═O of polybutylene terephthalate contained in the melt are exposed on the surface, and nonpolar sites such as alkylene chains are difficult to be exposed on the surface, and the region is 2910 cm ⁻¹ or more and 2930 cm ⁻¹ or less. Absorption peak a is less likely to occur. For these reasons, the peak intensity ratio Pa / Pb in the ATR-IR spectrum is set to a certain level or higher; that is, in order to easily expose the polybutylene terephthalate alkylene chain on the surface of the polyester resin layer, the melt is cast roll. It is preferable not to cool too rapidly. Specifically, the adhesion strength between the melt and the cast roll is reduced (for example, the adhesion method is a free method or an air chamber method); the adhesion time is shortened (for example, the line speed is increased). Is preferred.

  As described above, even when the crystallinity of the entire polyester resin layer is lowered, as shown from the result of the ATR-IR spectrum, the alkylene chain (nonpolar site) of polybutylene terephthalate is oriented on the surface of the polyester resin layer. Thus, high releasability can be obtained.

  In addition, the inventors of the present invention have used a diffraction profile in the out-of-plane direction obtained by measuring the outermost layer of the polyester resin layer of the release film by GIWAXS (Grazing Incidence Wide Angle X-ray (Neutron) Scattering). It has been found that the releasability is enhanced even when a specific peak is present.

FIG. 2 is a diagram showing an example of an out-of-plane diffraction profile obtained by performing GIWAXS measurement on the outermost layer of the polyester resin layer of the release film of the present invention. As shown in FIG. 2, the release film of the present invention has a peak (q = 16.16) derived from a crystal lattice plane (100) parallel to the film plane in the diffraction profile in the out-of-plane direction obtained by GIWAXS measurement. 4 nm ⁻¹ ).

  In the above-mentioned wide-angle X-ray diffraction (XRD) measurement, the crystallinity of the entire polyester resin layer can be known; whereas in the GIWAXS measurement, the X-ray incident angle is changed to change the depth direction (thickness). Direction) crystallinity. From these, in the diffraction profile of the out of plane (out-of-plane direction) obtained by GIWAXS measurement on the outermost layer of the polyester resin layer, peaks derived from crystal lattice planes (100) and (010) parallel to the film plane Existence means that the outermost layer of the polyester resin layer is not amorphous but crystalline.

  GIWAXS measurement can be performed under the conditions of an incident angle θ = 0.08 ° and a wavelength λ = 0.1 nm using a large synchrotron radiation facility SPring-8 (Hyogo) polymer beam line BL03XU. Then, a one-dimensional diffraction profile of Out of plane (out-of-plane direction) is obtained from the obtained two-dimensional diffraction profile, and the presence or absence of a peak derived from the crystal lattice plane (100) parallel to the film surface is confirmed.

  In order to generate a peak derived from the crystal lattice plane (100) parallel to the film surface, as described above, the adhesion strength between the melt and the cast roll is lowered; or the adhesion time is shortened. Can be adjusted.

  In order to improve the followability of the release film to the mold shape, it is preferable to adjust the storage elastic modulus E 'at the mold temperature. Since a typical example of the mold temperature is 120 ° C., it is preferable to use the storage elastic modulus E ′ at 120 ° C. as a guide. That is, the storage elastic modulus E ′ at 120 ° C. of the release film of the present invention is preferably 30 MPa or more and 200 MPa or less, more preferably 65 MPa or more and 150 MPa or less.

  If the storage elastic modulus E ′ at 120 ° C. of the release film is too low, the mechanical strength of the release film may not be sufficient. On the other hand, when the storage elastic modulus E ′ at 120 ° C. is too high, the release film is too hard, so that it cannot be stretched along the shape of the mold (it cannot follow) and wrinkles may occur.

The storage elastic modulus E ′ of the release film can be measured according to the following method.
Using a dynamic viscoelastic device RSA-II (manufactured by TA Instruments), tensile mode: vibration frequency 1 Hz, measurement speed: speed of 3 ° C./minute from −80 ° C. to a temperature at which the sample melts and becomes unmeasurable The elastic modulus in the conveyance direction (MD direction) of the release film is measured while raising the temperature at, and the storage elastic modulus E ′ at 120 ° C. is calculated.

  The ten-point average roughness RzJIS on the surface of the polyester resin layer of the release film is preferably 0 μm or more and 1.5 μm or less. By setting RzJIS within the above range, a sealing body with high surface smoothness and high light condensing properties can be easily obtained, particularly when performing LED resin sealing.

  The ten-point average roughness RzJIS of the surface of the polyester resin layer of the release film is a method based on JIS-B0601; specifically, a surface roughness type measuring machine (surfcom 130A, manufactured by Tokyo Seimitsu Co., Ltd.) It can be measured at a measurement length of 40 mm and a speed of 0.3 mm / s.

  The ten-point average roughness RzJIS of the surface of the polyester resin layer of the release film can be adjusted by, for example, the surface roughness of a cast roll or a touch roll in the film production process described later.

  The polyester resin layer disposed in the outermost layer of the release film of the present invention has a crystallinity measured by wide angle X-ray diffraction (XRD) adjusted to a certain level or less. In such a release film, since the outermost layer has an appropriate flexibility, the mold followability is good even for a complicated mold shape. Moreover, the peak intensity ratio Pa / Pb in the ATR-IR spectrum of the outermost layer of the polyester resin layer of the release film of the present invention is adjusted to a certain level or more. Since many alkylene chains (nonpolar sites) constituting the main chain of polybutylene terephthalate are exposed on the surface of such a polyester resin layer, good releasability is exhibited. Thus, the release film of the present invention can achieve both good mold followability and release properties.

2. Production method of release film The release film of the present invention can be produced by any method. For example, 1) a melt of a resin composition constituting a polyester resin layer, and other layers as necessary It can be obtained through a step of extruding the melt of the resin composition to be performed, and 2) a step of cooling and solidifying the extruded melt on a cast roll (cooling roll).

  Hereinafter, an example of producing a release film 29 composed of a single polyester resin layer will be described with reference to FIG.

  FIG. 3 is a schematic diagram showing an example of a part of a film manufacturing apparatus. As shown in FIG. 3, the film manufacturing apparatus 20 mainly includes a die 21, and a cast roll 23 and a touch roll 25 that cool the molten product pushed out from the die 21 while pinching it.

  In the step 1), the resin composition constituting the polyester resin layer is melt-kneaded with a melt extruder to obtain a melt. And the obtained melt is extruded to a film form from a die. When manufacturing a laminated film, a feed block method, a multi-hold die method, a dual slot die method, or the like can be adopted.

  In the step 2), the extruded melt is solidified while being narrowed by the cast roll 23 and the touch roll 25 to obtain a release film.

  The cast roll 23 is preferably a metal roll. The touch roll 25 may be a flexible roll having a thin metal outer cylinder having flexibility.

  The crystallinity of the release film can be adjusted mainly by the temperature of the cast roll 23. The temperature of the cast roll 23 depends on, for example, the molding temperature (melting temperature) of the melt, the adhesion strength between the cast roll 23 and the melt, the type of film production apparatus, and the like. Preferably, the temperature is 15 ° C. or more and 40 ° C. or less. If the temperature of the cast roll 23 is too high, the cooling tends to be insufficient. For this reason, the degree of crystallinity of the obtained release film is increased, and the mold followability may be lowered.

  The peak intensity ratio Pa / Pb in the ATR-IR spectrum of the outermost layer of the release film is mainly adjusted by the temperature of the cast roll 23, the adhesion strength between the cast roll 23 and the film-like melt, and the adhesion time (line speed). In particular, it can be adjusted by the adhesion strength between the cast roll 23 and the film-like melt.

  That is, if the cast roll 23 and the film-like melt are brought into close contact with each other, the melt is excessively cooled on the cast roll 23, and the surface energy of the melt is not sufficiently relaxed. As a result, the alkylene chain (nonpolar site) of polybutylene terephthalate is hardly exposed on the surface of the obtained release film, and the peak intensity ratio Pa / Pb in the ATR-IR spectrum tends to be low. Therefore, although the adhesion strength between the cast roll 23 and the film-like melt depends on the temperature of the cast roll 23, it is preferable to make it low, for example, a system that does not forcibly adhere (free system); It is preferable to adopt a method (air chamber method) or the like in which air is applied to the surface and closely adhered.

  The line speed during film formation is preferably increased and is preferably 10 to 30 m / min. If the line speed is too low, not only is the production efficiency low, but the temperature of the cast roll is easily transmitted to the melt (too rapidly cooled). Therefore, the peak intensity ratio Pa / Pb in the ATR-IR spectrum is lowered; it is difficult to expose the alkylene chain of polybutylene terephthalate on the film surface.

  The surface roughness of the cast roll 23 may be adjusted so that the RzJIS of the surface of the release film to be obtained (preferably the surface in contact with the object to be molded) is in the above range.

  The temperature of the touch roll 25 can be the same as the temperature of the cast roll 23. The surface roughness of the touch roll 25 should just be adjusted so that RzJIS of the other surface of the release film obtained may become the above-mentioned range.

  The film obtained by solidification while being sandwiched between the cast roll 23 and the touch roll 25 may be further conveyed by another roll 27 or the like as necessary. Thereby, the release film 29 comprised by the polyester resin layer single layer can be obtained.

3. Die Molding Method Using Release Film The release film of the present invention is used as a release film for mold molding, and is particularly preferably used as a release film for producing a semiconductor element sealing body. .

  That is, the manufacturing method of the semiconductor element sealing body of the present invention includes a first step of disposing a release film in a molding die and a second step of disposing a substrate on which the semiconductor element is mounted in the mold. Separating the process, the third step of filling the mold with a sealing resin and clamping the mold to cure the sealing resin to obtain a semiconductor element sealing body; and the obtained semiconductor element sealing body. And a fourth step of peeling from the mold film.

  The semiconductor element is preferably a light emitting element or a light receiving element, and more preferably an LED chip.

  4A to 4E are schematic views illustrating an example of a manufacturing process of an LED sealing body. As shown in FIG. 4A, a release film 31 is placed on a lower mold 33b of a molding mold 33 including an upper mold 33a and a lower mold 33b in which a cavity 32 having a predetermined shape is formed.

  When the release film 31 is a laminated film including a polyester resin layer (release layer A) containing polybutylene terephthalate, the surface opposite to the release layer A is in contact with the inner surface of the lower mold 33b; The mold layer A is disposed so as to contact a sealing resin 39 described later. And the release film 31 arrange | positioned at the lower metal mold | die 33b is closely_contact | adhered to the inner surface of the lower metal mold | die 33b, for example by operation, such as attraction | suction. The mold temperature at the time of suction may be, for example, the same temperature as at the time of mold molding (first step).

  The cavity 32 for manufacturing the LED sealing body has a hemispherical shape with a diameter of about 0.5 to 3 mm or a similar shape. That is, as compared with a mold for manufacturing a sealing body of a conventional semiconductor element, a mold for manufacturing an LED sealing body is a parting surface between an upper mold 33a and a lower mold 33b. To the deepest part of the cavity 32 is large.

  In addition, the board | substrate 35 which mounted several LED37 is arrange | positioned at the upper metal mold | die 33a (2nd process). The substrate 35 can be a ceramic substrate, a silicon substrate, a metal substrate, a resin substrate such as a polyimide resin.

  Next, as shown in FIG. 4B, a sealing resin 39 is filled as a molding material between the upper mold 33 a and the lower mold 33 b through the release film 31. The sealing resin 39 can be a thermosetting resin such as a silicone resin or an epoxy resin. Among these, a resin having a transparent cured product is preferable, and a silicone resin is preferable because it is suitable for manufacturing an LED encapsulant. The silicone resin may be an aromatic silicone resin or an aliphatic silicone resin.

  Thereafter, as shown in FIG. 4C, the LED 37 is placed in the encapsulating resin 39 filled in the mold 33 and the mold is clamped. Although the pressure at the time of mold clamping is not specifically limited, it is about 1.0-10.0 MPa. Moreover, the temperature at the time of mold clamping is not particularly limited, but may be about 110 to 190 ° C.

  Then, the sealing resin 39 is cured under predetermined conditions. The mold temperature at the time of curing can be adjusted according to the type of the sealing resin 39. For example, when a silicone resin is used as the sealing resin 39, the temperature is usually 80 to 160 ° C .; when an epoxy resin is used, the temperature is usually 150 to 200 ° C. (third step).

  Thereafter, as shown in FIG. 4D, the mold 33 is opened. Since the release film 31 is excellent in releasability, it can be easily released from the mold 33 (upper mold 33a and lower mold 33b) and the sealing resin 39. Through the above operation, an LED sealing body 40 as shown in FIG. 4E can be obtained (fourth step).

  The release film of the present invention includes a polyester resin layer containing polybutylene terephthalate, and the crystallinity of the polyester resin layer measured by wide-angle X-ray diffraction (XRD) is adjusted to a certain level or less. Therefore, when fixing the release film to the inner surface of the mold in the first process described above, or when performing mold molding in the third process (particularly when performing mold molding in the third process), Since the release film is moderately flexible, it can follow well along the complex shape of the mold without tearing or wrinkling.

  In addition, a lot of alkylene chains (nonpolar sites) of polybutylene terephthalate are exposed on the surface of the polyester resin layer of the release film of the present invention (the peak intensity ratio in the ATR-IR spectrum is adjusted to a certain level or more). ) Therefore, the mold release film of the present invention has improved mold release properties on the film surface while having flexibility. In particular, even when the sealing resin is a silicone resin; preferably an aliphatic silicone resin, it can have good releasability. Thereby, the sealing body obtained after shaping | molding can be easily peeled from a release film.

  Although the mold forming method using the release film of the present invention has been described in the example of the method for producing an LED encapsulant, it is not limited to this and can be preferably used in various molding methods using a mold. Moreover, the release film of the present invention is not limited to the above-described molding method, and can also be used in a molding method such as transfer molding applied to sealing of a normal semiconductor element.

  In the following, the invention will be described in more detail with reference to examples. These examples do not limit the scope of the present invention.

1. Release film material Novaduran 5020: Polybutylene terephthalate resin (Mitsubishi Engineering Plastics, non-reinforced HB grade extrusion, Tm: 224 ° C)
NOVADURAN 5010CS: Polybutylene terephthalate resin (Mitsubishi Engineering Plastics, Tm: 223 ° C)

2. Production of release film (Example 1)
Novaduran 5020 was melt-plasticized at 270 ° C. (molding temperature) with an extruder and then extruded from a T-die onto a cast roll to obtain a release film 1 having a thickness of 50 μm. The temperature of the cast roll was 40 ° C., and the close contact of the cast roll was free.

(Examples 2-3, Comparative Example 1)
The material of the release film, the molding temperature, and the temperature of the cast roll were changed as shown in Table 1, and the adhesion between the melt and the cast roll was performed in the same manner as in Example 1 except that the adhesion was performed by the air chamber method. Release films 2 to 4 were obtained. Adhesion between the melt and the cast roll by the air chamber method was performed by applying air having a wind pressure of 6.1 × 10 ⁻² MPa from the surface of the melt.

(Comparative Examples 2 to 4)
The release film material, the molding temperature, and the cast roll temperature were changed as shown in Table 1 and the melt and the cast roll were adhered by the electrostatic pinning method. Mold films 5 to 7 were obtained. The adhesion between the melt and the cast roll by the electrostatic pinning method was performed by applying 4 to 5 V static electricity to the melt.

(Comparative Example 5)
The release film 7 formed in Comparative Example 4 was further heat-treated at 90 ° C. for 30 minutes to obtain a release film 7 ′.

(Comparative Example 6)
A release film for FPC manufactured by Sekisui Chemical Co., Ltd. An RP film (main component: polybutylene terephthalate, thickness: 50 μm) was prepared as a release film 8.

  The obtained release film was measured for 1) crystallinity by XRD, and 2) peak intensity ratio in ATR-IR spectrum by the following methods.

(Crystallinity by XRD)
The obtained release film was cut into 30 mm × 30 mm, and the degree of crystallinity by wide angle X-ray diffraction (XRD) was measured with the following apparatus and conditions.
Device: Rigaku RINT2500
Output: 50kV-300mA
Target: Cu (CuKα)
Optical system: Parallel beam method optical system Measurement speed: 2 ° / min
Angular measuring range: 2θ = 5-35 °
From the integrated intensity of the peak at the diffraction angle of 2θ = 7 to 35 ° at which diffraction peaks of both the amorphous part and the crystalline part of the resin appear, the crystallinity (%) was calculated by the following formula (2). .
Crystallinity (χc) = (Integral intensity of crystalline part (peaks near 2θ = 16 °, 17 °, 20 °, 23 °, 25 °) / part containing amorphous and crystalline (2θ = 7) Integral intensity of ˜35 °) × 100 (%) Expression (2)

(Peak intensity ratio in ATR-IR spectrum)
ATR measurement was performed using a Fourier transform infrared spectrophotometer (manufactured by JASCO Corporation, FT-IR8300) to obtain an FT-IR spectrum (ATR-IR spectrum). The ATR crystal was Ge, and the infrared light incident angle θ was 60 °. Baseline was the line connecting the flat portion in the vicinity of 3050 cm ^-1 and near 2750 cm ^-1 (see Figure 1). Then, the peak intensity was obtained by reading the height of the peak at a predetermined wavelength from the baseline. Specifically, reading the maximum absorption peak intensity of 2910cm ^-1 or 2930 cm ^-1 following areas Pa, 2950 cm ^-1 or 2970cm ^-1 The following maximum absorption peak intensity Pb regions respectively, the peak intensity ratio (Pa / Pb) Was calculated.

  Furthermore, using the obtained release film, the mold following property and release property of the release film when an LED sealing body was produced by the following method were evaluated by the following methods.

(Mold followability)
As shown in FIGS. 5A to 5E, lenses were molded using a simple lens evaluation mold. First, a lower mold 64 was prepared in which 100 hemispherical holes with a radius of 1.25 mm and 300 hemispherical holes with a radius of 0.9 mm were arranged on the inner surface of the mold at equal intervals. Next, the release film 67 was disposed on the inner surface of the lower mold 64 and fixed with the outer frame 65 (see FIG. 5A). Next, evacuation was performed from a slit portion (not shown) processed on the side surface portion of the mold, and the release film 67 was made to follow the lens shape of the lower mold 64 (see FIG. 5B). The mold temperature during evacuation was 120 ° C.

  On the other hand, a stainless steel plate 62 (thickness: 1 mm) to which a polyimide tape (thickness: 50 microns) was attached was disposed on the upper mold 61. The planar dimension of the stainless steel plate 62 was 200 × 78 mm; the planar dimension of the release film 67 was 200 × 300 mm; and the planar dimension of the lower mold 64 was 46 × 88 mm.

  Next, 1.4 mL of a silicone resin (OE6636 (aromatic silicone resin) manufactured by Toray Dow Corning) as a sealing resin 63 was measured and injected onto the release film 67 with a syringe (see FIG. 5C).

Subsequently, it compressed in the up-down direction using the 20t hydraulic molding machine (the Toho Machinery company make, illustration not shown) (refer FIG. 5D). The compression conditions were temperature: 120 ° C., pressure: 91 kgf / cm ² (3 MPa), and compression time: 5 minutes. By this compression, the release film 67 is stretched following the shape of the hole of the lower mold 64, and the liquid silicone resin enters the holes of the release film 67 formed by stretching, and is heated and cured. A hemispherical lens (sealing body) made of silicone resin was molded by the reaction.

Next, after releasing the mold and peeling off the release film, the molded lens 88 was taken out (see FIG. 5E). And the surface state (presence or absence of wrinkles) of the obtained lens 88 is observed at a magnification of 100 times using an optical microscope (Keyence microscope VHX-1000 / 1100), and the mold following property is evaluated according to the following criteria. did.
○: No wrinkles transferred from the release film are observed on the lens surface ×: Wrinkles transferred from the release film are observed on the lens surface

(Releasability)
After molding the LED sealing body, the ease of peeling of the release film from the sealing body was visually observed when the mold was opened, and the mold release property was evaluated according to the following criteria.
◎: After molding, the mold release film does not stretch when the mold is opened ○: After mold, the mold release film is slightly stretched when the mold is opened, but the mold is released ×: The mold release film is a sealing body (lens) Stick and don't release

  OE6636 (aromatic silicone resin) manufactured by Toray Dow Corning, which is a silicone resin, was changed to LPS3412 or KER2500 (both aliphatic silicone resins) manufactured by Shin-Etsu Chemical Co., Ltd., respectively. The mold followability and releasability of the mold film were evaluated. However, the compression conditions when using KER2500 manufactured by Shin-Etsu Chemical Co., Ltd. were temperature: 120 ° C., compression time: 3 minutes.

These evaluation results are shown in Table 1. CR in the table indicates a cast roll.

  It can be seen that the release films of Examples 1 to 3 can achieve both good followability and release properties. In particular, it can be seen that the releasability is good regardless of the type of sealing resin. On the other hand, the release films of Comparative Examples 1 to 6 cannot achieve both good followability and release properties (particularly when LPS3412 or KER2500 manufactured by Shin-Etsu Chemical Co., Ltd. is used as the sealing resin). Recognize.

  Specifically, in the release films of Comparative Examples 2 and 4, since the melt and the cast roll are too closely adhered, the peak intensity ratio Pa / Pb in the ATR-IR spectrum is low and the release property is low. Recognize. This is thought to be because the proportion of the alkylene chains (nonpolar sites) of the polybutylene terephthalate exposed on the film surface was reduced because the melt was overcooled on the cast roll. Moreover, since the release film of Comparative Examples 1 and 3 has a relatively high cast roll temperature, it can be seen that the crystallinity is high and the followability is low. In addition, since the release film of Comparative Example 3 is too close to the melt and the cast roll, the peak intensity ratio Pa / Pb in the ATR-IR spectrum is low, and the polybutylene terephthalate alkylene chain on the surface of the release film. It can be seen that there is little exposure of (nonpolar part).

  It can be seen that the release film of Comparative Example 5 has low followability because the crystallinity of the entire film is increased by post-heat treatment. Further, the release film of Comparative Example 5 has a relatively high crystallinity of the whole film, but the crystallinity of the film surface is not selectively increased, so that sufficient release properties cannot be obtained. I understand.

  ADVANTAGE OF THE INVENTION According to this invention, it can provide the mold release film which has favorable followable | trackability also to the metal mold | die of a complicated shape, and has favorable mold release property.

29, 31, 67 Release film 20 Film production device 21 Die 23 Cast roll 25 Touch roll 27 Roll 32, 66 Cavity 33 Mold 33a, 61 Upper mold 33b, 64 Lower mold 35 Substrate 37 LED
39, 63 Sealing resin 40 LED sealing body 62 Stainless steel plate 65 Outer frame 88 Lens (sealing body)

Claims (5)

Polyester resin layer containing polybutylene terephthalate (however, a functional group having a melting point of 60 ° C. or more selected from the group consisting of fatty acids having 18 or more carbon atoms, fatty acid esters of polyhydric alcohols, fatty acid metal salts, fatty acid amides and modified type polyolefin ring waxes) A release film used for resin sealing of LED elements, comprising a single layer film of a release agent (B-1) having a melting point or a polyolefin resin (B-2) having a melting point of 100 ° C. or higher). There,
The degree of crystallinity of the polyester resin layer measured by wide angle X-ray diffraction (XRD) is 15% or more and 25% or less,
In the FT-IR spectrum obtained by measuring the outermost layer of the polyester resin layer using Ge as an ATR crystal by an ATR method and an infrared light incident angle of 60 °, a region of 2910 cm ⁻¹ or more and 2930 cm ⁻¹ or less When the maximum absorption peak intensity in the region of Pa and the maximum absorption peak intensity in the region of 2950 cm ^{−1 to} 2970 cm ⁻¹ is Pb, the relationship of the following formula (1) is satisfied:
0.6 ≦ Pa / Pb ≦ 2.0 Formula (1)
The release film whose thickness of the said release film is 20-100 micrometers.   The release film of Claim 1 whose sealing resin used for the said resin sealing is a silicone resin. Placing the release film according to claim 1 or 2 on the inner surface of the mold;
Placing the substrate on which the LED element is mounted in the mold; and
Filling the mold with a sealing resin, clamping the mold, and curing the sealing resin to obtain an LED element sealing body; and
Peeling the release film from the LED element sealing body;
The manufacturing method of the LED element sealing body containing this.   The manufacturing method of the LED element sealing body of Claim 3 which arrange | positions the said release film on the said metal mold | die inner surface so that the outermost surface of the said polyester resin layer may oppose the said LED element.   The said sealing resin is a manufacturing method of the LED element sealing body of Claim 3 or 4 which is a silicone resin.

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