Release film, method for sealing semiconductor component, and method for producing resin molded article

Abstract

Provided is a mold release film having flexibility, which is characterized in that a mold release layer is directly laminated on a resin film in the range of 2 g / m2 to 10 g / m2 inclusive, and the resin film has a tensile strength of 20 MPa or more, an elongation at break of 300% or more, and a thickness of 10 [mu] m to 100 [mu] m inclusive. As a result, provided is a mold release film in which a mold release layer is directly laminated on a resin film, the mold release film not only having good mold release properties, but also being capable of withstanding the environment encountered during mold molding of a resin, and further having flexibility capable of following a mold.

Description

[0001] This invention is a divisional application of Chinese Patent Application No. 202180033955.5, filed on March 30, 2021, entitled "Sealing method for release film and semiconductor component, manufacturing method of resin molded article". This application claims priority to Japanese Patent Application No. 2020-083203, filed on May 11, 2020. Technical Field

[0002] This invention broadly relates to a release film for easily removing a substrate of molding material or easily removing a resin molded article from a molding apparatus, primarily a mold-forming device, during a resin molding process. It relates to a release film for, for example, a resin molding process based on compression molding. Background Technology

[0003] Various molding methods have been developed for resins, including coating molding, extrusion molding, and injection molding. The molding method and conditions are also differentiated based on the characteristics of the resin, such as whether it is a thermosetting or thermoplastic resin. Release films are widely used in various molding processes. Without using release films, it is necessary to spray a release agent onto the resin-contacting parts inside the molding apparatus, raising concerns about damage or deformation of the resin molded product when removing it from the molding apparatus. Alternatively, additives may be needed to facilitate demolding from the self-molding device.

[0004] In this regard, a release film can easily remove the molded resin product from the molding device during the molding process and prevent the molding device from being contaminated by resin components. For example, resin is molded on the release film, and the release film is peeled off after molding. That is, the release film must have the strength to withstand the heat and pressure environment during the molding process and be able to be peeled off from the resin after molding.

[0005] As a common release film, a release film with a release layer laminated on a PET resin film is used (Patent Documents 1 and 2). However, when the resin molded product becomes more complex during molding, or when dimensional accuracy is required, the release film with PET resin film as the base material has poor mold followability and cannot obtain a resin molded product that is identical to the mold.

[0006] In this regard, fluoropolymer films (Patent Document 3) are cited as an example of resin films that possess mold-following properties and can withstand the heat and pressure during the molding process. Fluoropolymer films not only exhibit good mold release properties but also sometimes show thermoplasticity, and have excellent mold-following properties when heated. However, it is known that fluoropolymers produce harmful substances when burned, and operators designated by the Industrial Waste Management Act must treat them. Furthermore, their high price is well-known, posing a price issue.

[0007] In addition, there is a known invention that uses an adhesive layer to laminate a release layer onto a resin film (Patent Document 4), but it requires an adhesive layer to laminate the release layer, which complicates the processing of the release film and raises concerns that the adhesive layer may peel off.

[0008] Release agents are chemical agents used to smoothly remove molded products from molds during the process of filling molds with materials such as food, concrete, castings, and resins. Methods include direct application to the mold, spraying, and applying the release agent to a resin film as an interface between the mold and the material. The choice of release agent depends on the material. For example, for food, oils, paraffin wax, and vegetable waxes are often used. For concrete, vegetable oils are used. Furthermore, for organic materials such as rubber or resin, fluorinated and silicone-based release agents are known.

[0009] However, fluorinated mold release agents present several drawbacks, including the aforementioned disposal methods and high prices. Furthermore, while silicone mold release agents have fewer disposal and price issues compared to fluorinated ones, they do pose a problem of low-molecular-weight siloxanes contaminating molds or equipment. Besides fluorinated and silicone mold release agents, mold release agents using acrylic resins and melamine resins are also available, and various combinations are possible depending on the desired application.

[0010] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2020-011521 Patent Document 2: Japanese Patent No. 6653485 Patent Document 3: Japanese Patent No. 6481616 Patent Document 4: Japanese Patent Application Publication No. 2020-019263 Summary of the Invention

[0011] (a) Technical problems to be solved The purpose of this invention is to provide a release film in which a release layer is directly laminated on a resin film, which not only has good release properties, but also can withstand the environment encountered during resin molding, and further has the flexibility to follow the mold.

[0012] (II) Technical Solution To address the aforementioned technical problems, this invention provides a release film, which is a flexible release film, wherein the release layer has a content of 2 g / m³. 2 Above and 10g / m 2 The following method is used to directly laminate onto a resin film, wherein the resin film has a tensile strength of 20 MPa or more, an elongation at break of 300% or more, and a thickness of 10 μm or more and 100 μm or less.

[0013] Therefore, it is possible to provide a release film with a release layer directly laminated on a resin film, which not only has good release properties, but also can withstand the environment encountered during resin molding, and further has the flexibility to follow the mold.

[0014] Furthermore, it is preferable that the melting point of the resin film is above 200°C.

[0015] Therefore, it can be used for a wider range of processing applications.

[0016] Furthermore, it is preferable that the release force of the release film is 0.4 N / 25 mm or less.

[0017] If the release force is low, less force is needed to peel it off from the resin molded product, and the film will not break during the peeling process.

[0018] Furthermore, it is preferable that the silicone resin content in the release layer is less than 3%.

[0019] Therefore, there will be no pollution caused by siloxanes.

[0020] Furthermore, the release film is preferably used in the resin sealing process of semiconductor components based on compression molding.

[0021] This makes it easy to seal semiconductor components with resin.

[0022] Furthermore, the present invention provides a method for sealing semiconductor components, which uses the above-mentioned release film in a resin sealing process based on compression molding.

[0023] The release film of the present invention can be used in resin sealing, which makes the sealing process of semiconductor components easier.

[0024] Furthermore, the present invention provides a method for manufacturing resin molded articles, wherein the above-mentioned release film is used when molding the resin.

[0025] By using the release film of the present invention in the manner described above, the resin molded article can be easily removed.

[0026] (III) Beneficial Effects As described above, the present invention is an invention of a release film, providing a release film with a release layer directly laminated on a resin film. It not only has good release properties, but can also withstand the environment faced during resin molding, and further has the flexibility to follow the mold. The release film is inexpensive and does not produce harmful gases when discarded, and will not have an adverse impact on the environment. Attached Figure Description

[0027] Figure 1This is a schematic diagram of the molding method performed in the embodiments and comparative examples. Detailed Implementation

[0028] As mentioned above, there is a need to develop a release film with a release layer directly laminated on a resin film, which not only has good release properties, but also can withstand the environment encountered during resin molding, and further has the flexibility to follow the mold.

[0029] The inventors of this application have conducted in-depth research on the above-mentioned technical problems and found that if the release film, which is described later as having a release layer directly laminated on a resin film with specific physical properties, can solve the above-mentioned technical problems, thus completing the present invention.

[0030] That is, the present invention is a release film, which is a flexible release film, wherein the release layer has a content of 2g / m 2 Above and 10g / m 2 The following method is used to directly laminate onto a resin film, wherein the resin film has a tensile strength of 20 MPa or more, an elongation at break of 300% or more, and a thickness of 10 μm or more and 100 μm or less.

[0031] The present invention will now be described in detail, but it is not limited thereto.

[0032] [Resin film] Resin films are formed by molding a resin, which is polymerized through a polymerization reaction of organic molecules, into a film. The resin is not particularly limited; examples include polyester resin, polyethylene resin, nylon resin, and polyacrylic resin. Molding methods vary depending on the resin used, including extrusion molding and stretch molding. Resin films can be made from materials such as Lumirror (PET film, manufactured by TORAY INDUSTRIES, INC.), RAYFAN (nylon film, manufactured by TORAYINDUSTRIES, INC.), and ACRYPLEN (acrylic film, manufactured by Mitsubishi Chemical Corporation.), and meet the requirements of a tensile strength of 20 MPa or higher and an elongation at break of 300% or higher.

[0033] <Tensile strength of resin film> The tensile strength of the resin film used as the substrate is 20 MPa or more, preferably 30 MPa or more. There is no particular upper limit, but it is preferably 300 MPa or less, more preferably 150 MPa or less. If it is less than 20 MPa, the film may break due to the pressure during molding. Furthermore, the tensile strength is measured according to JIS-C-2318.

[0034] <Elongation at break of resin film> The elongation at break of the resin film used as the substrate is 300% or more, preferably 400% or more. There is no particular upper limit, but it is preferably 3000% or less, more preferably 1500% or less. If it is less than 300%, the mold followability is poor, and the dimensional accuracy of the resin molded article cannot be obtained. Furthermore, the elongation at break is measured using the method described in JIS C 2318:2007.

[0035] <Resin film thickness> The thickness of the resin film used as the substrate is 10 μm or more and 100 μm or less. Preferably, it is 30 μm or more and 70 μm or less. If it is less than 10 μm, even with high strength, the film may still break due to the pressure during molding or wrinkles may form on the film during molding. Furthermore, if it is greater than 100 μm, even with sufficient elongation, it may not follow the shape of the mold. In addition, there is a concern that the heat from the mold may not be sufficiently transferred to the resin.

[0036] <Melting Point> The melting point of the resin film is preferably 200°C or higher, more preferably 220°C or higher. While not particularly limited thereto, it is preferably 500°C or lower, more preferably 400°C or lower. A melting point of 200°C or higher allows for a wider range of processing applications.

[0037] [Mold Release Layer] The release layer is 2g / m 2 Above and 10g / m 2 The following method involves directly laminating the resin film. Preferably, the lamination is at a concentration of 2 g / m³. 2 Above and 6g / m 2 The following method involves directly laminating the resin film. If the density is less than 2 g / m³,... 2 If the resin film's flexibility is not fully utilized, the release effect may be compromised. If it exceeds 10g / m³... 2 This could cause the release layer to become too thick, thus compromising its flexibility as a release film.

[0038] If adhesives are used to laminate the release layer onto the resin film, a process of applying the adhesive to the resin film is required, and there is a concern that the release layer and the resin film may peel off due to pressure or heat during molding.

[0039] There are no particular limitations on the release agent as long as it can be directly cured and laminated on the resin film and has release force; commercially available products can be used.

[0040] For organic materials such as rubber or resin, fluorinated and silicone release agents are known as mold release agents.

[0041] However, fluorinated mold release agents present several drawbacks, including the aforementioned disposal methods and high prices. Furthermore, while silicone mold release agents are less problematic in terms of disposal and price compared to fluorinated ones, they suffer from the issue of low-molecular-weight siloxanes in their components potentially contaminating molds or equipment. To address these issues, in addition to fluorinated and silicone mold release agents, mold release agents using acrylic resins and melamine resins are also available, with various combinations depending on the desired application.

[0042] Any of the above-mentioned release agents can also be used in this invention.

[0043] <Silicone resin content in the release layer> The silicone resin content in the release layer is preferably 0% or more and 3% or less, more preferably 2.5% or less. While there are no problems if it is not particularly important, depending on the molding apparatus, contamination by siloxanes is sometimes undesirable. Therefore, the silicone resin content is preferably kept below 3%.

[0044] [Demolding force] The release force of the release film is preferably greater than 0.02 N / 25 mm and less than 0.4 N / 25 mm. More preferably, it is less than 0.35 N / 25 mm. If it is less than 0.4 N / 25 mm, the release force on the resin is low enough that no large force is required when peeling it off from the resin molded article, and the film will not break during the peeling process. In addition, the release force is a value obtained by measuring the following load: a 25 mm wide adhesive tape is applied to the release film, and at 70 g / m 2 After being subjected to a load at 25°C for one day, the load was further applied at 20g / m 2 The load required for peeling is measured at 70°C for 1 day, and the adhesive surface is peeled off at a peeling speed of 0.3 mm / min in a 180° direction. Additionally, Nitto 31B tape (manufactured by NITTO DENKO CORPORATION) is used as the adhesive tape.

[0045] [Manufacturing method of release film] In manufacturing a release film, the release layer needs to be stacked on the resin film and cured. For example, the release agent can be diluted with an appropriate organic solvent, a curing agent and additives can be added, and then the release agent can be applied to the resin film in a predetermined amount using a Mayer bar coater. The solvent can then be allowed to evaporate and the film can be cured under predetermined curing conditions.

[0046] The manufacturing method is not particularly limited to this.

[0047] [Disposal of release film] Since the release film used in the molding process is essentially discarded, waste disposal needs to be considered, preferably incineration. For example, when it is a fluoropolymer film, since it produces harmful gases when burned, it will be incinerated or landfilled by designated companies subject to waste disposal laws. This not only incurs costs during disposal but also requires consideration of the environmental impact.

[0048] [How to use release film] The release film of this invention can be applied to the resin sealing process of semiconductor components based on compression molding. This makes resin sealing of semiconductor components easier.

[0049] In addition, a method for sealing semiconductor components using the above-mentioned release film in a resin sealing process based on compression molding is also provided.

[0050] Furthermore, a method for manufacturing a resin molded article using the above-mentioned release film during resin molding is also provided.

[0051] By using the release film of the present invention, it is possible to withstand the heat and pressure environment during the molding process when sealing, and it can be quickly peeled off from the resin after molding, making resin sealing easy. In addition, when manufacturing resin compositions that become more complex in mold molding and resin compositions that require dimensional accuracy, the good mold followability allows for obtaining resin molded articles that are identical to the mold, and the resin molded articles can be easily removed.

[0052] Semiconductors consist of components, solder, leads, lids, etc., and require protection from light, heat, dust or moisture, and physical impact; therefore, resin sealing is performed. The resin is typically epoxy resin, which is then mixed with curing agents and additives and heated to cure. The sealing process involves placing the component to be sealed and the epoxy resin in a mold, and applying heat and pressure to shape it into the desired form. In this case, the release film of the present invention can be used. Examples of conventional sealing materials include CEL-8240 (manufactured by Hitachi Chemical) and KMC-2990 (manufactured by Shin-Etsu Chemical Co., Ltd.), but the sealant that can be used in the present invention is not limited to these.

[0053] Example The present invention will now be described in more detail, but the invention is not limited to these embodiments.

[0054] [Evaluation Method] In this embodiment and comparative example, a release film was prepared in the manner described later, and the release force of the release film was measured. Furthermore, the number of steps required to manufacture the release film was determined.

[0055] Then, using a mold release film prepared during the molding of epoxy sealant KMC-2990 (manufactured by Shin-Etsu Chemical Co., Ltd.) with an effective size of 60×60×0.5mm, the mold followability and release properties of the release film were evaluated. The curing conditions were 180°C for 5 minutes with an applied pressure of 8MPa. Details of the molding method are as follows... Figure 1 As shown.

[0056] Between the lower mold 1 and the upper mold 1', the release film 2, the epoxy sealant 3, and another release film 2 (A) are inserted sequentially from the bottom, and then heated and pressurized 4 (B) to form the epoxy sealant (C), and then the release film 2 is peeled off.

[0057] <Mold Follow-up> If the size of the molded sheet is measured and the difference from the theoretical size is within 40 μm, the mold conformity is evaluated as good.

[0058] <Desiccant> A release film is rated as good when it can be peeled off without breaking after resin molding.

[0059] <Number of steps required to manufacture the release film> When the release layer is directly laminated onto the resin film, it is rated as one process; when the adhesive is applied to the resin film and the release layer is laminated, it is rated as two processes.

[0060] <Demolding force> The following load was measured: a 25mm wide adhesive tape was applied to the release film at a load of 70g / m². 2 After being subjected to a load at 25°C for one day, the load was further applied at 20g / m 2 The load required for peeling is determined by peeling the adhesive surface at a peeling speed of 0.3 mm / min in a 180° direction after one day at 70°C. Additionally, Nitto 31B adhesive tape (manufactured by NITTO DENKOCORPORATION) is used.

[0061] [Examples 1-7, Comparative Examples 1-4] Release films were manufactured by directly laminating release layers with combinations shown in Tables 2 and 3 onto a resin film having the characteristics shown in Table 1 below, and were used as Examples 1 to 7 and Comparative Examples 1 to 4. The release force, mold following properties, release properties, and number of steps required to manufacture the release films were investigated using the above method. These results are shown in Tables 2 and 3.

[0062] [Table 1] <Mold Release Agent> The following shows the release agent used and the method for forming a release layer using the release agent.

[0063] Release agent 1: X-70-201S (manufactured by Shin-Etsu Chemical Co., Ltd.) Using a dissolver, mix release agent 1, CAT-PL-50T (manufactured by Shin-Etsu Chemical Co., Ltd.), and SF diluent (manufactured by Shin-Etsu Chemical Co., Ltd.) in a ratio of 100 / 0.5 / 200 to prepare a coating solution. Apply the solution using a Mayer rod and then cure it at 130°C for 1 minute.

[0064] Release agent 2: KS-847 (manufactured by Shin-Etsu Chemical Co., Ltd.) Using a dissolving machine, mix release agent 2, CAT-PL-50T, and toluene in a ratio of release agent 2 / CAT-PL-50T / toluene = 100 / 10 / 200 to prepare a coating solution. Apply the solution using a Mayer rod and then cure it at 140°C for 30 seconds.

[0065] Release agent 3: X-62-9088 (manufactured by Shin-Etsu Chemical Co., Ltd.) Using a dissolving machine, mix release agent 3, CAT-PS-80 (manufactured by Shin-Etsu Chemical Co., Ltd.), MEK, and toluene in a ratio of release agent 3 / CAT-PS-80 / MEK / toluene = 100 / 0.9 / 450 / 450 to prepare a coating solution. Apply the solution using a Mayer rod and then cure it at 120°C for 1 minute.

[0066] [Table 2] [Table 3] [Comparative Example 5] Using a dissolving machine, urethane adhesive TAKELAC A-616 (manufactured by Mitsui Chemicals, Inc.), TAKENATE A-65 (manufactured by Mitsui Chemicals, Inc.), and ethyl acetate were stirred at a ratio of TAKELAC A-616 / TAKENATE A-65 / ethyl acetate of 16 / 1 / 10 to prepare a coating solution. Then, a Mayer rod was used to coat the solution at a concentration of 1.5 g / m³. 2 The resin film 1 with a thickness of 50 μm was coated and dried at 60 °C for 2 minutes. Then, an unstretched 4-methyl-1-pentene copolymer resin film (with a thickness of 15 μm) was further laminated to obtain a release film.

[0067] In the example, a 2 g / m² coating was used on a resin film with sufficient tensile strength and elongation. 2 The release film produced by the above release agents exhibits sufficiently low release force, resulting in excellent mold followability and release properties. Furthermore, the manufacturing process of the release film involves only one step: directly applying the release layer onto the resin film and allowing it to cure.

[0068] For Comparative Example 1, due to the lack of a release layer, the release properties were significantly impaired, making it impossible to peel the film from the resin; therefore, mold followability could not be evaluated. For Comparative Example 2, because the resin film used PET with insufficient elongation, adequate mold followability was not obtained. For Comparative Example 3, due to the low amount of release agent applied, the release layer could not follow the elongation of the resin film during molding, resulting in poor release properties. For Comparative Example 4, because the film thickness exceeded 100 μm, it did not follow the shape of the mold.

[0069] For Comparative Example 5, although the mold following and demolding properties were good, the demolding layer was not directly stacked on the demolding film but an adhesive was used, so two processes were required to manufacture the demolding film.

[0070] As mentioned above, the release layer is 2g / m 2 Above and 10g / m 2 The following method of directly laminating a flexible release film onto a resin film with a tensile strength of 20 MPa or higher, an elongation at break of 300% or higher, and a thickness of 10 μm or higher and 100 μm or less provides good mold followability and release properties.

[0071] Furthermore, this invention is not limited to the above-described embodiments. The above embodiments are merely examples, and any technical solutions having substantially the same structure and producing the same technical effects as the technical concept described in the claims of this invention are included within the technical scope of this invention.

Claims

1. A release film, which is a flexible release film, characterized in that, The release layer is 2g / m 2 Above and 10g / m 2 The following method is used to directly laminate the resin film, wherein the resin film has a tensile strength of 20 MPa or more, an elongation at break of 300% or more, and a thickness of 10 μm or more and 100 μm or less. The release layer is formed by using a release agent, which is any one of silicone release agents, acrylic resin release agents, and melamine resin release agents. The silicone resin content in the release layer is less than 3%.

2. The release film according to claim 1, characterized in that, The resin film has a melting point of 200°C or higher.

3. The release film according to claim 1, characterized in that, Its demolding force is less than 0.4N / 25mm.

4. The release film according to claim 2, characterized in that, Its demolding force is less than 0.4N / 25mm.

5. The release film according to any one of claims 1 to 4, characterized in that, The release film is used in the resin sealing process of semiconductor components based on compression molding.

6. A method for sealing a semiconductor component, characterized in that, The release film according to any one of claims 1 to 5 is used in a resin sealing process based on compression molding.

7. A method for manufacturing a resin molded article, characterized in that, The release film according to any one of claims 1 to 5 is used when molding the resin.

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