TWI728132B - Mold release film and manufacturing method of semiconductor package - Google Patents

Abstract

The purpose of the present invention is to provide a resin with high adhesiveness to be molded The new manufacturing method of resin molded products. A method of manufacturing a resin molded product, comprising: a step of preparing a release film 10, the release film 10 comprising a support layer 11 having mold releasability, and a temporary transfer layer provided on one side of the support layer 11 12; The step of extruding the resin with a mold through the release film 10; the step of transferring the temporary transfer layer 12 of the release film 10 to the sealing portion 25 of the resin molded product; The step of removing the temporary transfer layer 12 of the section 25.

Description

Mold release film and manufacturing method of semiconductor package

The invention relates to a method for manufacturing a release film and a resin molded product.

In the manufacture of printed circuit boards, ceramic electronic parts, semiconductor packages, and other electronic device sealing parts, or various other resin products, a release film is used to prevent the resin from adhering to the mold or roller.

As the material of the release film, a material having high releasability in nature and heat resistance that can withstand the molding temperature is used. For example, a method of using a fluorine-based resin such as ethylene-tetrafluoroethylene copolymer (ETFE) as a release film is known. Furthermore, Patent Document 1 discloses a method of using a biaxially oriented polystyrene-based film containing a syndiotactic polystyrene (SPS)-based resin and an antioxidant as a release film.

[Prior Art Literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2015-21017

However, due to the resin, there is a phenomenon that even if the mold release film as described above is used, the mold release film adheres to the resin molded product.

The object of the present invention is to provide a new method of manufacturing a resin molded product formed by molding such a resin with high adhesiveness/adhesiveness. Furthermore, its purpose is to provide a release film that can be preferably used in such a manufacturing method.

The mold release film of the present invention is a mold release film used in resin molding, and is characterized in that it includes a support layer having mold releasability, and a temporary transfer layer provided on one side of the support layer, and the temporary transfer layer The printing layer transfers at least a part of the resin molded product, and removes it from the resin molded product. The release film of the present invention is used between a resin and a forming mold (for example, a metal mold, a resin mold) or a roll. Therefore, when the resin is molded using a molding die or roller, the resin does not contact the molding die or roller. Furthermore, since only the temporary transfer layer is transferred to the resin molded product, it can be easily removed from the resin molded product. This release film is suitable when molding a resin with high adhesiveness/adhesiveness using a molding die or a roller.

In the release film of the present invention, when the thickness of the temporary transfer layer is 35 μm or less, it is further easier to remove the temporary transfer layer after the transfer on the resin molded product. In the release film of the present invention, when the support layer has a biaxially oriented SPS-based polymer film, it is excellent in release properties, heat resistance, and chemical resistance.

The method of manufacturing a resin molded article of the present invention is characterized by including the step of preparing a release film, the release film including a support layer having mold releasability, and a temporary transfer layer provided on one side of the support layer; The step of molding the resin through the release film; the step of transferring at least a part of the temporary transfer layer of the release film to the resin molded article; the temporary transfer on the resin molded article The step of removing the transfer layer. The manufacturing method of the resin molded article of the present invention can reduce the wear of the molding die without complicating the manufacturing steps. It is particularly suitable for molding resins with poor releasability and high adhesiveness/adhesion using a molding die.

The step of molding the resin in the present invention is preferably a step of molding the resin with a mold or roller. The step of removing the temporary transfer layer of the present invention is preferably a step of removing the temporary transfer layer by grinding, spraying, or washing. In this case, the removal step of the temporary transfer layer can be simplified. Especially when the resin molded product is an electronic device including a resin sealing part, after the sealing part is molded, the surface of the sealing part is polished for thinning, the polishing step is performed to expose the connection electrode, etc. It can also be used for the removal of the temporary transfer layer, and the release film of the present invention can be used in the existing manufacturing steps without adding further steps.

As shown in FIG. 1, the release film of the present embodiment includes a support layer 11 having mold releasability, and a temporary transfer layer 12 provided on one side of the support layer 11 (the lower surface in FIG. 1 ). The release film 10 is a film for molding the resin 20 by the molding die 30 without directly contacting the resin molding surface 30a of the molding die 30 and the resin 20, which is arranged between the resin 20 and the molding die 30 (see FIG. 2 In a, b).

The support layer 11 is in contact with the resin molding surface 30 a of the molding die 30. The support layer 11 is excellent in releasability and slidability with respect to the molding die 30, and has toughness that follows the irregularities of the molding die 30. Moreover, it has heat resistance that can withstand the forming temperature. The thickness of the support layer 11 is preferably 20 μm or more, more preferably 25 μm or more, particularly preferably 30 μm or more, preferably 100 μm or less, more preferably 90 μm or less, still more preferably 80 μm or less, particularly preferably 75 μm the following. Too thin or too thick will make the manufacturing or operation complicated.

The support layer 11 includes polyester resins such as styrene-based polymers, propylene-based polymers, ethylene-based polymers, polyethylene terephthalate (PET), polyvinyl fluoride (PVF), and polyvinylidene fluoride. (PVDF) or ethylene-tetrafluoroethylene copolymer (ETFE) and other synthetic resin films such as fluorine-based resins. The styrene-based polymer is preferably a polymer having a syndiotactic structure (SPS-based polymer). The types of SPS polymers include polystyrene, poly(alkylstyrene), poly(halogenated styrene), poly(halogenated alkylstyrene), poly(alkoxystyrene), poly(vinylbenzene) Formate), their hydrogenated polymers, and their mixtures, or copolymers containing them as main components. Poly(alkylstyrene) can include poly(methylstyrene), poly(ethylstyrene), poly(isopropylstyrene), poly(tertiary butylstyrene), poly(phenylstyrene) ), poly(vinyl naphthalene), poly(vinyl styrene), etc. Examples of poly(halogenated styrene) include poly(chlorostyrene), poly(bromostyrene), poly(fluorostyrene), and the like. Examples of poly(halogenated alkylstyrene) include poly(chloromethylstyrene) and the like. Examples of poly(alkoxystyrene) include poly(methoxystyrene) and poly(ethoxystyrene).

The synthetic resin film is preferably a biaxially aligned resin film. For example, simultaneous or sequential extension can be used to perform biaxial alignment. Such a biaxially aligned synthetic resin film is preferably an SPS-based polymer simultaneous (sequential) biaxially stretched film or a PET simultaneous (sequential) biaxially stretched film, and particularly preferably an SPS-based polymer simultaneous (sequential) biaxially stretched film.

On the other hand, like the release film 10a shown in b in FIG. 1, the support layer 11 may have a two-layer structure or a multilayer structure of three or more layers. In this case, for example, the layer 11a that is in contact with at least the resin molding surface 30a of the molding die is a layer having excellent releasability and slidability with respect to the resin molding surface 30a of the molding die. In addition, at least the layer 11 b that is in contact with the temporary transfer layer 12 is a layer that is easily peeled from the temporary transfer layer 12 or a layer with a low interlayer adhesion strength to the temporary transfer layer 12.

The temporary transfer layer 12 is a layer in contact with the resin 20. In addition, the temporary transfer layer 12 is transferred to the surface of the resin molded product after the resin 20 is molded into a resin molded product, and the release film 10 is transferred to the surface of the resin molded product, and then removed from the resin molded product. . The interlayer adhesion strength of the temporary transfer layer 12 to the resin 20 is greater than the interlayer adhesion strength of the temporary transfer layer 12 to the support layer 11. Therefore, after the resin 20 is sealed, the temporary transfer layer 12 can be easily peeled off from the supporting layer 11 and transferred to the resin molded product. In addition, the temporary transfer layer 12 has toughness that follows the irregularities of the forming mold. In addition, it is preferable that the influence of the molding temperature is small. For example, it is preferable not to thermally decompose to generate gas or foam, or embrittlement to generate cracks. Furthermore, when the temporary transfer layer 12 is removed from the resin molded product by grinding or spraying, it is preferable that the temporary transfer layer 12 has low viscosity and low elasticity. On the other hand, when the temporary transfer layer 12 is washed with a liquid (water, solvent) and removed from the resin molded product, it is preferable that the temporary transfer layer 12 exhibits solubility in the liquid (water, solvent).

The thickness of the temporary transfer layer 12 is preferably 35 μm or less, more preferably 25 μm or less, and particularly preferably 15 μm or less. If it is too thick, removal after transfer to the resin molded product becomes complicated. On the other hand, if it is too thin, it will be difficult to build up the layer. There are cases where the film breaks during resin molding and the resin 20 penetrates the temporary transfer layer 12 and comes into contact with the support layer 11. , It is particularly preferably 1 μm or more. The temporary transfer layer 12 can be laminated on one side of the support layer 11 by coating, extrusion lamination, thermal lamination, vapor deposition, sputtering, dry lamination, printing, or the like. The material of the temporary transfer layer 12 can be appropriately selected according to the materials of the support layer 11 and the resin 20. For example, synthetic resins include polyolefin resins such as polyethylene or polypropylene, polyvinyl alcohol, polyester resins, acrylic resins, polyurethane resins, epoxy resins, polyamide resins, Silicone resins, fluorine resins, synthetic rubbers, etc. and their modified products and mixtures. In addition, metals or metal oxides, silicon dioxide, etc., or various printing inks can also be cited.

Next, the manufacturing method of the resin molded article of this embodiment is demonstrated. The method of manufacturing a resin molded article of the present embodiment includes: a step of preparing a release film 10; a step of extruding the resin 20 with a molding die 30 through the release film 10; and temporarily transferring the release film 10 The step of transferring the layer 12 on the resin molded product; the step of removing the temporary transfer layer 12 transferred on the resin molded product.

A to c in FIG. 2 show the outline of the process of extruding the resin 20 with the molding die 30 through the release film 10. In this step, the sealing portion 25 covering the upper surface of the substrate 15 is formed. Preferably, it is a sealing portion of a semiconductor package that seals a substrate on which a semiconductor element is mounted.

As shown in a in FIG. 2, the forming mold 30 includes an upper forming mold 31 and a lower forming mold 32. The upper mold 31 is provided with a recess 31a, and if the upper mold 31 and the lower mold 32 are brought close to each other, a space is generated. The inner surface of the recess 31a becomes a resin molding surface 30a. Next, as shown in b in FIG. 2, the release film 10 is deformed along the concave portion 31 a of the upper mold 31 and fixed to the upper mold 31 (a lower surface in a in FIG. 2 ). The fixing of the release film 10 can be performed by suction from the suction port 31b of the upper mold 31, for example. On the other hand, the substrate 15 is placed on the lower mold 32, and the resin 20 is filled thereon. Thereby, between the upper molding die 31 and the lower molding die 32, the substrate 15, the resin 20, and the release film 10 are sequentially arranged from the bottom. In addition, the substrate 15 is preferably fixed to the lower mold 32. The fixing can be performed by suction from the suction port 32a of the lower mold 32, for example. Furthermore, as shown in c in FIG. 2, the resin molding surface 30a of the upper molding die 31 is heated to the molding temperature, so that the upper molding die 31 (or the lower molding die 32) is close to the lower molding die 32 (or the upper molding die). 31), while pressing the space between the upper molding die 31 and the lower molding die 32, the resin 20 is molded into the sealing portion 25. The molding temperature can be selected according to the resin 20 to be molded. For example, it is 100°C or higher, preferably 130°C or higher, particularly preferably 150°C or higher, and the upper limit is about 250°C or lower, and usually 200°C or lower. For the resin molded at about 130°C to 200°C, it is preferable to use an SPS stretched film, particularly an SPS biaxially stretched film, as the support layer 11.

In the manufacturing method of this embodiment, the substrate 15, the resin 20, and the release film 10 may be sequentially arranged from the bottom to perform resin molding, and the positional relationship may be turned upside down. That is, the release film 10 may be fixed to the lower mold, the substrate 15 may be fixed to the upper mold, and the resin 20 may be arranged on the mold release film 10. In the manufacturing method of this embodiment, the resin 20 is used for compression molding in which the resin 20 is compressed on one side by the upper and lower molding dies, but it is not limited to this. For example, it can also be used in injection molding or transfer molding in which a space formed between upper and lower molding dies is filled with molten resin or powdered or liquid prepolymer and solidified. In addition, it can also be used in roll forming. In addition, the forming mold may not use a metal mold but a resin mold.

Examples of the resin 20 include thermosetting resins such as epoxy resins, melamine resins, urea resins, alkyd resins, and polyimide resins, or polyester resins, polyurethane resins, and acrylic resins. Thermoplastic resins such as resins. In particular, epoxy resins have low oxygen/moisture permeability and high chemical resistance, and are therefore suitable for sealing parts of electronic devices such as semiconductor packages, printed circuit boards, and ceramic electronic parts. Examples of resin molded products include semiconductor packages with sealing portions, printed circuit boards, ceramic electronic components, and other electronic devices, thermosetting resin products, thermoplastic resin products, and the like. Particularly preferred is a semiconductor package. In addition, in this embodiment, a semiconductor package that seals one side of the substrate is exemplified, but it may be a semiconductor package that seals the entire substrate. In this case, a release film is sandwiched between the upper mold and the resin and between the lower mold and the resin to perform resin molding.

Next, the step of transferring the temporary transfer layer 12 of the release film 10 to the resin molded product will be described. That is, after separating the upper molding die 31 from the lower molding die 32, or at the same time as the separation, the release film 10 is separated from the resin molded product, thereby making the temporary transfer layer 12 of the release film 10 self-supporting layer 11 It is peeled off and transferred to the sealing part 25 of the resin molded product. A in FIG. 3 indicates that only the part of the temporary transfer layer 12 that is in contact with the sealing part 25 is transferred onto the sealing part 25. That is, the temporary transfer layer 12 is partially cut and divided into a part 12 a transferred on the sealing portion 25 and a part 12 b remaining on the release film 10. In this case, the subsequent removal step of the temporary transfer layer 12 becomes easy. B in FIG. 3 indicates that all of the temporary transfer layer 12 is transferred to the sealing portion 25. C in FIG. 3 is to transfer a part of the temporary transfer layer 12 in contact with the sealing part 25 to the sealing part 25. That is, like a in FIG. 3, the temporary transfer layer 12 is divided into a part 12 a transferred on the sealing portion 25 and a part 12 b remaining on the release film 10.

Finally, the step of removing the temporary transfer layer 12 transferred on the resin molded product will be described. As a method of removing the temporary transfer layer 12 transferred to the sealing portion 25 of the resin molded product, methods such as polishing, spraying, or cleaning can be cited. For example, the method of manufacturing a semiconductor package includes a step of polishing the surface of the sealing portion for thinning after the sealing portion 25 is formed. However, this polishing step may also serve as a step of removing the temporary transfer layer 12. In this case, existing equipment can be used, and manufacturing can be performed with the same number of steps as before, so that the complexity of the manufacturing steps can be avoided, and the manufacturing cost can be suppressed. [Example]

[Example 1] Polyvinyl alcohol (PVA) was coated on one side of a 50 μm SPS-based polymer simultaneous biaxially stretched film (support layer 11) to provide a PVA layer (temporary transfer layer 12) to obtain the release of Figure 1模膜10。 Mold film 10. The thickness of the PVA layer after coating and drying was 10 μm. This is referred to as Example 1. [Example 2] A linear low-density polyethylene (LLDPE) was extruded and laminated on one side of a 50 μm SPS-based polymer simultaneous biaxially stretched film (support layer 11), and a 15 μm LLDPE layer was provided (temporary transfer). Printing layer 12), the release film 10 of FIG. 1 is obtained. This is referred to as Example 2. [Example 3] Linear low-density polyethylene (LLDPE) was extruded and laminated on one side of a PET simultaneous biaxially stretched film (support layer 11) to provide a 15 μm LLDPE layer (temporary transfer layer 12) to obtain The release film 10 of FIG. 1. This is referred to as Example 3. The structure of Example 1 to Example 3 is shown in Table 1.

[Table 1]

Using the release films 10 of Examples 1 to 3, the resin 20 was extruded and molded by the molding die 30 including the upper molding die 31 and the lower molding die 32 as shown in a and b in FIG. 4. In detail, the substrate 15, the resin 20, and the release film 10 are arranged in order from the bottom between the upper and lower molds, and the resin molding surface 30a of the upper mold 31 is heated to the molding temperature, so that the upper mold 31 is close to the lower mold. The mold 32 molds the resin 20 at the sealing portion 25 of the resin molded product. In addition, the symbol 16 is a spacer that controls the approach of the upper mold 31 and the lower mold 32. As the resin 20, an epoxy resin sheet (prepolymer) is used. The thickness of the substrate 15 was 1 mm, the molding temperature was 180° C., and the molding (hot pressing) time was 3 minutes. In any embodiment, after the sealing part 25 is formed, the release film 10 is separated from the sealing part 25 to transfer the temporary transfer layer 12 of the release film 10 to the sealing part 25. In any embodiment, the transferred temporary transfer layer 12 is removed from the sealing portion 25 by grinding or spraying. In addition, in the case of using the release film 10 of Example 1, the temporary transfer layer 12 can also be removed by washing with water.

10, 10a‧‧‧Release film 11‧‧‧Supporting layer 11a‧‧‧Layer 11b‧‧‧At least in contact with the resin molding surface 30a of the forming mold 11b‧‧‧At least in contact with the temporary transfer layer 12 12‧‧‧Temporary Transfer layer 12a‧‧‧Transferred part 12b‧‧‧Remaining part 15‧‧‧Substrate 16‧‧‧Spacer 20‧‧‧Resin 25‧‧‧Seal part 30‧‧‧Forming mold 30a‧‧‧ Resin molding surface 31‧‧‧Upper mold 31a‧‧‧Concavity 31b‧‧‧Suction port 32‧‧‧Lower mold 32a‧‧‧Suction port

A in Fig. 1 is a side view showing one embodiment of the release film of the present invention, and b in Fig. 1 is a side view showing another embodiment of the release film of the present invention. A, b, and c in FIG. 2 are schematic diagrams respectively showing the resin molding steps of the embodiment of the method for manufacturing a resin molded article of the present invention. Fig. 3 a is a schematic diagram showing the transfer step of the temporary transfer layer in the embodiment of the method for manufacturing a resin molded article of the present invention, and b and c in Fig. 3 respectively show the manufacture of the resin molded article of the present invention A schematic diagram of the transfer step of the temporary transfer layer in another embodiment of the method. A and b in FIG. 4 are schematic diagrams showing the resin molding steps of the embodiment.

10: Release film

11: Support layer

12: Temporary transfer layer

12a: Transferred part

12b: The remaining part

15: substrate

25: Sealing part

Claims (5)

A mold release film, which is a mold release film used in resin molding in a semiconductor packaging process, and is characterized in that it includes a support layer formed of a synthetic resin film with mold releasability, and a single layer provided on the support layer. Surface temporary transfer layer, the material of the support layer is selected from the group consisting of styrene polymers, propylene polymers, ethylene polymers, polyester resins and fluorine resins, the support layer A biaxially aligned SPS-based polymer film, the material of the temporary transfer layer is a polyolefin resin; the temporary transfer layer transfers at least a part of the resin molded product, and the resin molded product is polished The step is to remove it from the resin molded product. The release film according to the first item of the scope of patent application, wherein: the thickness of the temporary transfer layer is 35 μm or less. The release film according to item 1 or item 2 of the scope of patent application, wherein: the temporary transfer layer is laminated on the single side of the support layer by extrusion lamination. A method for manufacturing a semiconductor package, which is characterized by comprising: preparing the release film as described in any one of items 1 to 3 in the scope of the patent application; arranging a substrate, a resin, and the release film in sequence, and A step of compressing the resin with upper and lower molding dies while molding; a step of transferring at least a part of the temporary transfer layer of the release film to the sealing portion of the resin molded product; The step of removing the temporary transfer layer transferred on the sealing portion by polishing, and polishing the surface of the sealing portion. The method for manufacturing a semiconductor package as described in claim 4, wherein: the step of removing the temporary transfer layer transferred on the sealing portion by grinding is for the thinning of the semiconductor package And the step of polishing the surface of the sealing portion.

Images