TWI903125B - Manufacturing method of protective film and electronic device packaging - Google Patents

Abstract

This invention provides a protective sheet for use on a circuit board, the protective sheet having a first side and a second side opposite to the first side, wherein the adhesive force of the first side obtained by probe adhesion test is less than 0.15 N/ ^cm2 , and the index X calculated by the following formula 1 is 0.5 to 2.0, and the protective sheet contains filler at a content of 1.0% to 9.8% by weight. [Formula 1] X = F _total / T _total (F _total ; the average value (μm) of the flow length of the four sides of the most flowable part when a 0.5 cm × 1.0 cm rectangular protective sheet is heated and pressed at 180°C and 1 MPa for 5 minutes, T _total ; the total thickness (μm) of the protective sheet)

Description

Manufacturing method of protective film and electronic device packaging

This invention relates to a method for manufacturing a protective sheet and an electronic device package.

A method is known for forming an insulation layer on a substrate on which an integrated circuit (IC) chip is mounted to protect the chip from electromagnetic waves (e.g., Patent 1). [Patent 1] U.S. Patent 7,445,968

In a first embodiment of the present invention, a protective sheet is provided for use on a circuit board. The protective sheet has a first side and a second side opposite to the first side. The adhesive force of the first side, obtained by a probe adhesion test, is less than 0.15 N/ ^cm² , and the index X calculated by Equation 1 below is 0.5 to 2.0. The protective sheet contains filler at a content of 1.0% to 9.8% by weight. [Equation 1] X = F _total / T _total (F _total ; the average value (μm) of the flow length of the four sides of the most flowable portion when a 0.5 cm × 1.0 cm rectangular protective sheet is heated and pressed at 180°C and 1 MPa for 5 minutes, T _total ; the total thickness (μm) of the protective sheet)

The tensile breaking strength of the protective sheet can be 10 N/ ^mm² to 70 N/ ^mm² .

The protective sheet may include a first protective layer and a second protective layer. The first protective layer may be the outermost layer on the first side of the protective sheet. Furthermore, the second protective layer in the protective sheet may be the outermost layer on the second side.

In any of the protective sheets, the exponent Y of the second protective layer, calculated by the following formula 2, can be 0.5 to 1.5. [Formula 2] Y = F ₂ / T ₂ (F ₂ ; the average value (μm) of the flow length of the four sides of the most flowable part when the second protective layer, which is made into a rectangle of 0.5 cm × 1.0 cm, is heated and pressed at 180°C and 1 MPa for 5 minutes, and T ₂ ; the thickness (μm) of the second protective layer)

In any of the protective sheets, the index Z of the first protective layer, calculated by the following formula 3, can be 2.0 to 15.0. [Formula 3] Z = F ₁ / T ₁ (F ₁ ; the average value (μm) of the flow length of the four sides of the most flowable part when the first protective layer, which is made into a rectangle of 0.5 cm × 1.0 cm, is heated and pressed at 180°C and 1 MPa for 5 minutes, and T ₁ ; the thickness (μm) of the first protective layer)

In any of the protective sheets, the glass transition temperature of the second protective layer can be below 60°C.

In any of the protective sheets, the thickness of the first protective layer can be 5 μm to 150 μm, and the thickness of the second protective layer can be 10 μm to 200 μm.

In any of the protective sheets, a third protective layer may be included between the first protective layer and the second protective layer. Furthermore, the index W of the third protective layer, calculated by Equation 4 below, may be 1.0 to 3.0. [Equation 4] W = F _₃ / T _₃ (F _₃ : the average value (μm) of the flow length of the four sides of the most fluid portion when the third protective layer, which is made into a rectangle of 0.5 cm × 1.0 cm, is heated and pressed at 180°C and 1 MPa for 5 minutes), T _₃: the thickness (μm) of the third protective layer)

In any of the protective sheets, the thickness of the third protective layer can be 20 μm to 200 μm.

In any of the protective sheets, the first protective layer, the second protective layer, and the third protective layer may contain polyurethane resin and a hardener.

In any of the protective sheets, the protective sheet may include filler, and the mass concentration of the filler on the second side of the protective sheet may be greater than that on the first side.

In addition, in the second embodiment, an electronic device package is provided, comprising: a circuit substrate having conductive circuits disposed on its surface; an electronic device disposed on the circuit substrate; and a protective layer disposed on the circuit substrate and the electronic device, wherein the electronic device has a polygon with pentagons or more when viewed from the main surface of the circuit substrate or from the side of its own surface.

In the electronic device package, the electronic device may have a recess on its side.

In any of the electronic device packages, the electronic device may have a polygonal shape of pentagon or more when viewed on the main surface.

In addition, in the third embodiment, an electronic device package is provided, comprising: a circuit substrate having conductive circuits disposed on its surface; an electronic device disposed on the circuit substrate; and a protective layer disposed on the circuit substrate and the electronic device, the protective layer at least partially covering a connection structure that electrically connects the electronic device to the circuit substrate.

In the electronic device package, the connecting component may be a bump disposed on the lower surface of the electronic device.

In any of the electronic device packages, the connection component may be a lead frame that carries the electronic device.

In addition, in the fourth form, an electronic device package is provided, including: a circuit substrate having conductive circuits disposed on its surface; an electronic device disposed on the circuit substrate; and a protective layer disposed on the circuit substrate and the electronic device, wherein the electronic device has multi-layer ceramic capacitors (MLCCs).

In the electronic device package, the protective layer may include at least two layers.

In any of the electronic device packages, the protective layer may be a hardened form of a thermosetting resin.

In any of the electronic device packages, a conductive layer may be formed on the protective layer.

In the fifth aspect, a method for manufacturing an electronic device package is provided, comprising the following steps: mounting an electronic device on a mounting substrate on a substrate having conductive circuits disposed on its surface, arranging any one of the protective sheets with its first surface facing the electronic device side, and forming a protective layer formed by the protective sheet on the mounting substrate.

In the manufacturing method, the step of forming the protective layer may include hot-pressing the protective sheet onto the mounting substrate after it has been disposed.

The manufacturing method may further include a step of forming a conductive layer on the protective layer.

Furthermore, the summary of the invention does not list all the essential features of the invention. In addition, subcombinations of these feature groups can also constitute an invention.

The present invention will now be described through embodiments, but these embodiments do not limit the scope of the invention covered by the patent application. Furthermore, the combination of features described in the embodiments may not all be necessary for the solutions provided in the invention.

Figure 1 shows an example of an electronic device package 100 according to this embodiment. The electronic device package 100 is a package that houses electronic devices such as IC chips and has good electromagnetic wave shielding and heat dissipation. The electronic device package 100 includes a circuit board 10, electronic devices 20 and 22 (hereinafter also referred to as "electronic devices 20, etc."), a connection component 24, a protective layer 30, and a conductive layer 40.

The circuit substrate 10 has conductive circuits (not shown) disposed on its surface and carries electronic devices 20, etc. The circuit substrate 10 may be a printed wiring board or a mounting module board, etc. The conductive circuit may be a circuit formed of a conductive metal such as copper or a material containing a conductive metal. The circuit substrate 10 may be a rigid substrate or a flexible substrate.

The circuit board 10 can be processed as needed. For example, printing, marking, and cutting grooves can be provided on the circuit board 10.

Electronic devices 20 and the like are disposed on the circuit board 10 and perform various functions. These electronic devices 20 can be, for example, integrated circuits such as memory chips, power supply chips, audio chips, or central processing unit (CPU) chips; active components such as transistors or diodes; or passive components such as multilayer ceramic capacitors (MLCCs); and thermal resistors, inductors, or resistors. In particular, since MLCCs have external electrodes on their sides, insulation protection is especially necessary to prevent contact with other conductors or leakage. With the protective sheet of this embodiment, described later, the protective layer 30 can adequately insulate the entire MLCC component.

The electronic device 20 can be cubic or cuboid in shape. The electronic device 20 can also have more complex shapes, and can have polygons with more than pentagons when observed on the main surface of the circuit substrate (XY plane in FIG1).

For example, in electronic devices such as 20, the planar shape observed on the autonomous surface can be hexagonal, octagonal, or other polygonal. As an example, electronic device 22 can be an inductor with an octagonal planar shape. Furthermore, electronic devices such as 20 can have polygons of pentagonal or more when observed on the side of their autonomous surface (such as the XZ plane or YZ plane in FIG. 1). For example, electronic device 20 can be a cubic or cuboid shape with concave or convex portions on the side, and electronic device 22 can be an inductor with concave portions on the side for forming a coil.

One or more electronic devices 20 may be disposed on the circuit substrate 10. For example, electronic devices 20 may be formed on n×m arrays on the circuit substrate 10 (n and m are integers greater than 2).

Ideally, the thickness of the electronic devices 20 should be less than 2000 μm. This is because if it exceeds 2000 μm, the protective layer 30 and the conductive layer 40 may break due to the step difference with the circuit substrate 10 during formation. Furthermore, the spacing between the electronic devices 20 should ideally be more than 50 μm. This is because if the spacing is less than 50 μm, the protective layer 30 and the conductive layer 40 may not be sufficiently formed.

The connection component 24 electrically connects the electronic device 20 and the circuit board 10. The connection component 24 may include one or more of the following: solder balls or bumps disposed on the lower surface of the electronic device 20, a lead frame supporting the electronic device 20, and bonding wires. In the example of FIG1, bumps may be used as the connection component 24 for connecting the electronic device 20 and the circuit board 10.

A protective layer 30 is disposed on the circuit substrate 10 and electronic devices 20, etc., to protect the circuit substrate 10 and electronic devices 20 from the influence of electromagnetic waves, shocks, etc. In addition, the protective layer 30 also functions as a self-conductive layer 40 to provide insulation protection for the circuit substrate 10 and electronic devices 20. The protective layer 30 may cover the entirety or a portion of the electronic devices 20 and other areas of the circuit substrate 10 where electronic devices 20 are not disposed. The protective layer 30 may cover only the areas of the circuit substrate 10 where conductive circuits are disposed, or it may not cover the parts without conductive circuits.

Even when electronic devices such as 20 have complex shapes such as polygons, the protective layer 30 sufficiently covers the electronic devices 20. For example, even when electronic devices 22, as shown in FIG. 1, have recesses on their sides, the protective layer 30 penetrates into part or all of the recesses to protect the electronic devices 22. Furthermore, even when electronic devices such as 20 have polygonal shapes with many corners where the protective layer 30's film thickness is easily thinned, the protective layer 30 of this embodiment can sufficiently cover the corner portions.

The protective layer 30 may at least partially cover the connecting member 24. For example, in FIG1, the protective layer 30 covers the side of the connecting member 24, which is a protrusion. Even if the connecting member 24 includes a lead frame or a bonding wire, the protective layer 30 may cover at least a portion of those.

The protective layer 30 may be a cured form of a thermosetting resin, etc. The protective layer 30 may comprise at least two layers. For example, the protective layer 30 may have two, three, or four or more layers. To maintain the film thickness of the protective layer 30 within an appropriate range, the protective layer 30 is preferably three layers. Such layers may be formed from the layer structure derived from the protective sheet described later. The layer structure and materials of the protective layer 30 will be described later.

The thickness of the protective layer 30 can vary depending on the location. For example, at the corner of an electronic device 20, the protective layer 30 may be thinner than the top surface of the electronic device 20. Conversely, at a corner recess where an electronic device 20 contacts the circuit substrate 10, the protective layer 30 may be thicker than the top surface of the electronic device 20.

A conductive layer 40 is disposed on the protective layer 30 to protect the electronic device 20 from the influence of external electromagnetic waves and/or to dissipate heat generated by the electronic device 20 to the outside. The conductive layer 40 may be a layer containing metal. For example, the conductive layer 40 may be a metal thin film formed of the metal itself, or a resin layer with dispersed conductive fillers. Details of the materials of the conductive layer 40 will be described later.

In the case of thermosetting resins containing conductive fillers, the thickness of the conductive layer 40 can be 2 μm to 500 μm, preferably 5 μm to 100 μm. On the other hand, in the case of plating, evaporation, or sputtering, the thickness can be 0.01 μm to 10 μm, preferably 0.1 μm to 5 μm. If the thickness is too thin, the electromagnetic wave blocking effect, heat dissipation effect, and mechanical strength may become insufficient; if it is too thick, the electronic device package 100 will become too large, resulting in an increased volume.

The metal film and conductive filler used in the conductive layer 40 are preferably those with good electrical conductivity and/or thermal conductivity, for example, those with a volume resistivity of less than ^10⁻³ Ω·cm and/or a thermal conductivity of more than 10 W/m·K.

The conductive layer 40 may be connected to the grounding pattern exposed on the side or top surface of the circuit substrate 10 and/or the grounding pattern of the electronic device 20. Alternatively, the electronic device package 100 may not have the conductive layer 40.

Thus, through the electronic device package 100 of this embodiment, the protective layer 30 provides insulation protection for electronic devices 20 and the connecting components 24, which have complex shapes. In addition, through the electronic device package 100, the conductive layer 40 can protect electronic devices 20 and the like from electromagnetic waves, while also dissipating the heat generated by electronic devices 20 and the like.

Furthermore, as explained below, the protective layer 30 can be formed of a protective sheet 38. With the protective sheet 38, air entrapment will not occur between the protective layer 30 and the circuit board 10, and the complex-shaped electronic devices 20 and the like can be fully covered and insulatingly protected.

Figure 2 shows an example of the protective sheet 38 of this embodiment. The protective sheet 38 is a sheet for a circuit board used to form the protective layer 30 shown in Figure 1. As shown, the protective sheet 38 has a first protective layer 32, a second protective layer 34 and a third protective layer 36.

The protective sheet 38 has a first side (the lower side of FIG. 1) and a second side (the upper side of FIG. 1) opposite to the first side. The first side is in contact with the circuit board 10 and electronic devices 20, and the second side is in contact with the conductive layer 40. The first protective layer 32 is the outermost layer of the first side of the protective sheet 38. The second protective layer 34 is the outermost layer of the second side. A third protective layer 36 is disposed between the first protective layer 32 and the second protective layer 34.

The adhesive force obtained by probe adhesion test on the first side of the protective sheet 38 is less than 0.15 N/ ^cm² , preferably less than 0.12 N/ ^cm² , and more preferably less than 0.10 N/ ^cm² . The probe adhesion test can be performed by the same test method as or based on the test method in General Test Method 6.12 Adhesion Test Method 3.4 of the Eighteenth Amendment to the Japanese Pharmacopoeia.

By ensuring the adhesive strength meets the aforementioned range, the adhesiveness of the protective sheet 38 can be suppressed when it is disposed on the circuit substrate 10, preventing unwanted portions of the protective sheet 38 from adhering to the circuit substrate 10 or from wetting and spreading (so-called puddling). Additionally, if the protective sheet 38 has high adhesiveness, it may sometimes adhere to the circuit substrate 10 during pressing, hindering air expulsion (so-called air entrainment). However, with the protective sheet 38 having adhesive strength meeting the aforementioned range, air expulsion can proceed smoothly.

The adhesive force of the second side of the protective sheet 38, obtained by probe adhesion testing, can be 0.01 N/ ^cm² or higher, preferably 0.05 N/ ^cm² or higher, and more preferably 0.10 N/ ^cm² or higher. Furthermore, the difference in adhesive force between the first and second sides can be 0.05 N/ ^cm² to 0.40 N/ ^cm² , preferably 0.05 N/ ^cm² to 0.30 N/ ^cm² , and more preferably 0.10 N/ ^cm² to 0.20 N/ ^cm² . By satisfying the aforementioned range of adhesive force, the tightness of the cushioning material in contact with and deposited on the second side of the protective sheet is sufficiently ensured, thereby enabling efficient pressing. The cushioning material can be deposited on the protective sheet for the purpose of applying appropriate pressure during heat pressing.

Furthermore, the index X of the protective sheet 38, calculated by the following formula 1, can be 0.5 to 2.0, preferably 0.6 to 1.7, and more preferably 0.7 to 1.5. [Formula 1] X = F _total / T _total Here, F _total is the average value (μm) of the flow length of the four sides of the most flowable portion when the protective sheet 38, which is made into a rectangle of 0.5 cm × 1.0 cm, is heated and pressed at 180°C and 1 MPa for 5 minutes. _{T total} is the total thickness (μm) of the protective sheet 38. In the case of the protective sheet 38 in Figure 2, T _total is equal to the sum of the thicknesses of the first protective layer 32, the second protective layer 34, and the third protective layer 36. When the protective sheet 38 includes a peeling layer, the total thickness does not include the thickness of the peeling layer.

Figure 3 illustrates an example of the flow length in this embodiment. A 0.5 cm × 1.0 cm rectangular reference shape is cut by sandwiching the protective sheet 38 between two polyimide films. It is then pressed at 1 MPa for 5 minutes while maintaining a temperature of 180°C. During this time, a portion of the protective sheet 38 softens and flows between the polyimide films; therefore, the length of the most flowing portion from the polyimide film is measured for each side.

For example, as shown in Figure 3, flow is generated by extending from the four sides of a polyimide film 35 that has the same shape (reference shape) as the protective sheet 38 before pressing. Here, on each of the four sides, the lengths L1 to L4 from the side with the most flow are measured along a straight line extending 90 degrees from each side of the polyimide film 35. The average value of the flow lengths L1 to L4 on the four sides, expressed in μm, is taken as the flow length F _total (μm).

When the index X is within the aforementioned range, a sufficient amount of protective layer 30 is formed around the circuit substrate 10 and electronic device 20, thereby providing more reliable insulation protection for the electronic device package 100. On the other hand, if the index X is too large compared to the aforementioned range, the flowability of the protective sheet 38 during thermoforming is too high, resulting in insufficient thickness in a portion of the protective layer 30 (e.g., the corner of the electronic device 20).

If the index X is smaller than the range described above, the flowability of the protective sheet 38 during thermoforming will be insufficient, and the electronic device 20 and the like will not be adequately insulated and protected by the protective layer 30, resulting in a risk of insufficient voltage withstand capability. For example, the protective layer 30 may not be adequately formed at the concave corner where the circuit board 10 contacts the electronic device 20, around the connecting component 24, and/or around the electronic device 20 with a complex shape (especially the concave portion).

Furthermore, the tensile breaking strength of the protective sheet 38 can be 10 N/ ^mm² to 70 N/ ^mm² , preferably 15 N/ ^mm² to 50 N/ ^mm² , and even more preferably 20 N/ ^mm² to 40 N/ ^mm² . The tensile breaking strength can be measured according to Japanese Industrial Standards (JIS)-C-2151:2019. For example, the tensile breaking strength can be calculated as follows: using a tensile testing machine, the protective sheet 38 is stretched at a speed of 50 mm/min at 23°C and 60%RH, and the strength at which the protective sheet 38 breaks is calculated (tensile load value / cross-sectional area of the protective sheet 38).

If the tensile breaking strength is too high, the flowability of the protective sheet 38 during heat pressing will be insufficient, creating a risk that the electronic device 20 and the like will not be adequately insulated and protected by the protective layer 30. If the tensile breaking strength is too low, the flowability of the protective sheet 38 during heat pressing will be too high, resulting in insufficient thickness in a part of the protective layer 30 (e.g., the corner of the electronic device 20). On the other hand, when the tensile breaking strength is within the aforementioned range, a sufficient amount of protective layer 30 is formed around the circuit board 10 and the electronic device 20, thereby providing more reliable insulation protection for the electronic device package 100.

The thickness of the protective film 38 can be 50 μm to 500 μm, preferably 100 μm to 250 μm.

The first protective layer 32 primarily imparts fluidity to the protective sheet 38. The index Z of the first protective layer 32, calculated by Equation 2 below, can be 2.0 to 15.0, preferably 4.0 to 12.0, and even more preferably 5.0 to 10.0. [Equation 2] Z = F ₁ / T ₁ Here, F ₁ is the average value (μm) of the flow length of the four sides of the most fluid portion when the first protective layer 32, which is made into a rectangle of 0.5 cm × 1.0 cm, is heated and pressed at 180°C and 1 MPa for 5 minutes. _{T 1} is the thickness (μm) of the first protective layer 32. _{F 1} can be measured by the same method as F _total .

As described above, the exponent Z takes a larger value range than the exponent X. In this way, the first protective layer 32 flows well during the thermoforming of the protective sheet 38 and can enter the surrounding area (especially the recess) of the electronic device 20 with a complex shape, the connecting component 24, and/or the gap between the circuit board 10 and the electronic device 20.

If the index Z is too large compared to the stated range, the flowability becomes too high, resulting in insufficient thickness in parts of the protective layer 30 (e.g., corners of electronic devices 20, etc.). On the other hand, if the index Z is smaller than the stated range, the flowability of the protective sheet 38 during thermoforming is insufficient, creating a risk that electronic devices 20, etc., cannot be adequately insulated and protected by the protective layer 30. On the other hand, when the index Z is within the stated range, a sufficient amount of protective layer 30 is formed around the circuit board 10 and electronic devices 20, thereby providing more reliable insulation protection for the electronic device package 100.

The thickness of the first protective layer 32 can be 5 μm to 150 μm, preferably 5 μm to 50 μm, and more preferably 10 μm to 30 μm. By ensuring that the thickness of the first protective layer 32 meets the above range, appropriate flowability can be provided while suppressing the adhesion of the protective sheet 38.

The glass transition temperature of the first protective layer 32 can be below 80°C, preferably below 60°C, and even more preferably below 50°C. The glass transition temperature of the first protective layer 32 can be above 20°C, preferably above 30°C, and even more preferably above 35°C.

The second protective layer 34 primarily serves to ensure the thickness of the protective layer 30 while preventing ion migration caused by metal ions from the conductive layer 40 it contacts. The exponent Y of the second protective layer 34, calculated by Equation 3 below, can be 0.5 to 1.5, preferably 0.6 to 1.4, and more preferably 0.7 to 1.2. [Equation 3] Y = F ₂ / T ₂ Here, F ₂ is the average value (μm) of the flow length of the four sides of the most fluid portion when the second protective layer 34, which is made into a rectangle of 0.5 cm × 1.0 cm, is heated and pressed at 180°C and 1 MPa for 5 minutes. _{T 2} is the thickness (μm) of the second protective layer 34. _{F 2} can be measured by the same method as F _total .

As described above, when the exponent Y reaches the specified range, the second protective layer 34 will not flow excessively during the thermoforming of the protective sheet 38, and will remain firmly in areas where the protective layer 30 is prone to thinning, such as the corners of the electronic device 20. This provides more reliable insulation protection for the electronic device package 100. Furthermore, when the conductive layer 40 is formed on the protective layer 30, ion migration from the self-conductive layer 40 can be sufficiently prevented.

If the index Y is too large compared to the stated range, the flowability of the protective sheet 38 during heat pressing will be too high, resulting in insufficient thickness in a portion of the protective layer 30 (e.g., at the corner of the electronic device 20, etc.). On the other hand, if the index Y is smaller than the stated range, the flowability of the protective sheet 38 during heat pressing will be insufficient, and the electronic device 20, etc., will not be adequately insulated and protected by the protective layer 30, or there will be a risk of ion migration.

The thickness of the second protective layer 34 can be 10 μm to 200 μm, preferably 30 μm to 150 μm, and even more preferably 50 μm to 100 μm. By ensuring that the thickness of the second protective layer 34 meets the aforementioned conditions, the overall thickness of the protective layer 30 can be maintained while maintaining the heat dissipation of the electronic device 20, etc.

The second protective layer 34 may be thicker than the first protective layer 32. In this case, the insufficient thickness of a portion of the protective layer 30 (e.g., a corner of the electronic device 20) can be more reliably eliminated. Furthermore, the first protective layer 32 may be thicker than the second protective layer 34. In this case, the protective layer 30 can more reliably protect the periphery (especially recesses) of electronic devices 20 with complex shapes, the connecting components 24, and/or the gap between the circuit board 10 and the electronic device 20.

The glass transition temperature of the second protective layer 34 can be below 60°C, preferably below 50°C, and even more preferably below 40°C. The glass transition temperature of the second protective layer 34 can be above 0°C, preferably above 10°C, and even more preferably above 20°C. Furthermore, the glass transition temperature of the second protective layer 34 can be lower than that of the first protective layer 32. This ensures sufficient adhesion between the cushioning material in contact with the second protective layer 34 during heat pressing, thereby enabling efficient pressing.

The third protective layer 36 primarily serves to ensure the thickness of the protective layer 30 while maintaining a certain degree of fluidity. The index W of the third protective layer 36, calculated by Equation 4 below, can be 1.0 to 3.0, preferably 1.2 to 2.7, and even more preferably 1.5 to 2.5. [Equation 4] W = F ₃ / T ₃ Here, F ₃ is the average value (μm) of the flow length of the four sides of the most fluid portion when the third protective layer 36, which is made into a rectangle of 0.5 cm × 1.0 cm, is heated and pressed at 180°C and 1 MPa for 5 minutes. _{T 3} is the thickness (μm) of the third protective layer 36. _{F 3} can be measured using the same method as F _total .

As described above, the exponent W takes a value between the exponents Y and Z. Therefore, during the heat pressing of the protective sheet 38, the third protective layer 36 has the fluidity between the first protective layer 32 and the second protective layer 34, thus supplementing the coating effect performed by the first protective layer 32 and the second protective layer 34.

The thickness of the third protective layer 36 can be 20 μm to 200 μm, preferably 30 μm to 150 μm, and even more preferably 40 μm to 80 μm. By satisfying the aforementioned conditions with the thickness of the third protective layer 36, the following effects can be achieved: the protective layer 30 protects the periphery (especially the recesses) of electronic devices 20 with complex shapes, the connecting components 24, and/or the gap between the circuit substrate 10 and the electronic devices 20, and firmly retains the protective layer 30 in areas where the film thickness is prone to thinning.

Furthermore, the third protective layer 36 may comprise multiple layers. For example, the third protective layer 36 may be formed by laminating two identical resin films.

The third protective layer 36 may be thicker than the first protective layer 32. In this case, the situation where the thickness of a portion of the protective layer 30 is insufficient (e.g., the corner of the electronic device 20) can be eliminated more reliably. Alternatively, the first protective layer 32 may be thicker than the third protective layer 36. In this case, the protective layer 30 can more reliably protect the periphery (especially recesses) of electronic devices 20 with complex shapes, the connecting components 24, and/or the gap between the circuit board 10 and the electronic device 20.

The glass transition temperature of the third protective layer 36 can be below 60°C, preferably below 50°C, and even more preferably below 40°C. The glass transition temperature of the third protective layer 36 can be above 0°C, preferably above 10°C, and even more preferably above 20°C. Furthermore, the glass transition temperature of the third protective layer 36 can be lower than that of the first protective layer 32. This improves the impact absorption capacity of the third protective layer 36, thereby enhancing the overall impact absorption capacity of the protective layer 30.

At high temperatures, the second protective layer 34 can have a harder property than the first protective layer 32. For example, at 120°C, the Young's modulus of the second protective layer 34 can be higher than that of the first protective layer 32. For example, at 120°C, the Young's modulus of the first protective layer 32 can be 0.5 to 3, and the Young's modulus of the second protective layer 34 can be 3 to 7. The Young's modulus of the third protective layer 36 can be between that of the first protective layer 32 and the second protective layer 34, for example, it can be 1.5 to 3.5 at 120°C. By having such Young's moduli in the first protective layer 32 to the third protective layer 36, the protective sheet 38 can exhibit appropriate flowability at the high temperature of hot pressing.

The first protective layer 32, the second protective layer 34, and the third protective layer 36 may be thermosetting resins. For example, the first protective layer 32, the second protective layer 34, and the third protective layer 36 may comprise thermosetting resins and hardeners.

As a thermosetting resin, it can be used in polymers having one or more functional groups that undergo cross-linking reactions upon heating. Examples of functional groups include hydroxyl, phenolic hydroxyl, methoxymethyl, carboxyl, amino, epoxy, oxacyclobutyl, oxazolinyl, oxazinyl, aziridinyl, thiol, isocyanate, block isocyanate, block carboxyl, and silanol.

As an example of a thermosetting resin, one or more of the following can be used: polyurethane resin, acrylic resin, maleic acid resin, polybutadiene resin, polyester resin, urea resin, epoxy resin, oxocyclobutane resin, phenoxy resin, polyimide resin, polyamide resin, polyamide-imide resin, phenol resin, cresol resin, melamine resin, alkyd resin, amino resin, polylactic acid resin, oxazoline resin, benzoxazine resin, silicone resin, and fluorine resin. Two or three of the first protective layer 32, the second protective layer 34, and the third protective layer 36 may use the same or similar resins as thermosetting resins.

As a curing agent, one or more of the following can be used: epoxy-based curing agents, aziridine-based curing agents, phenolic curing agents, amine-based curing agents, isocyanate-based curing agents, and metal chelate-based curing agents. Furthermore, aziridine-based curing agents can be curing agents containing compounds having an aziridine group; phenolic curing agents can be curing agents containing compounds having a hydroxyl group directly bonded to an aromatic group (aromatic ring); amine-based curing agents can be curing agents containing compounds having an amino group; and isocyanate-based curing agents can be curing agents containing compounds containing an isocyanate group. Metal chelate-based curing agents can be curing agents containing complexes formed by the coordination of a polydentate ligand (chelate ligand) with a metal ion. Two or three of the first protective layer 32, the second protective layer 34, and the third protective layer 36 may use the same or similar hardener.

Epoxy-based curing agents can be epoxy compounds. Epoxy compounds are compounds having two or more epoxy groups per molecule. Epoxy compounds can be in liquid or solid form. Examples of epoxy compounds include glycidyl ether type epoxy compounds, glycidyl amine type epoxy compounds, glycidyl ester type epoxy compounds, and cyclic aliphatic (lipocyclic) epoxy compounds.

As a glycidyl ether type epoxide, it may be, for example, one or more selected from bisphenol A type epoxide, bisphenol F type epoxide, bisphenol S type epoxide, bisphenol AD type epoxide, cresol phenolic varnish type epoxide, phenol phenolic varnish type epoxide, α-naphthol phenolic varnish type epoxide, bisphenol A type phenolic varnish type epoxide, dicyclopentadiene type epoxide, tetrabromobisphenol A type epoxide, brominated phenol phenolic varnish type epoxide, tris(glycidyloxyphenyl)methane, tetra(glycidyloxyphenyl)ethane, etc.

Examples of glycidylamine type epoxides include tetraglycidyldiaminodiphenylmethane, triglycidylp-aminophenol, triglycidylm-aminophenol, and tetraglycidylm-xylyldimethylamine.

Examples of glycidyl ester-type epoxides include: diglyceride phthalate, hexahydrodiglyceride phthalate, tetrahydrodiglyceride phthalate, etc.

Examples of cyclic aliphatic (lipocyclic) epoxy compounds include epoxide cyclohexylmethyl-epoxide cyclohexane carboxylate and bis(epoxide cyclohexyl) adipate. Liquid epoxy compounds can also be used.

Aziridine-based hardeners can be aziridine compounds. Examples of aziridine compounds include, for instance, N,N'-diphenylmethane-4,4'-bis(1-aziridine carbonyl), N,N'-toluene-2,4-bis(1-aziridine carbonyl), bis(isophthalic acid)-1-(2-methylaziridine), tri-1-aziridine phosphine oxide, N,N'-hexamethylene-1,6-bis(1-aziridine carbonyl), trihydroxymethylpropane-tri-β-aziridine propionate, tetrahydroxymethylmethane-tri-β-aziridine propionate, tri-2,4,6-(1-aziridine)-1,3,5-triazine, trihydroxymethylpropane tris[3-(1-aziridine)propionate], and trihydroxymethylpropane. One or more of the following: alkyltris[3-(1-aziridinyl)butyrate], trihydroxymethylpropanetris[3-(1-(2-methyl)aziridinyl)propionate], trihydroxymethylpropanetris[3-(1-aziridinyl)-2-methylpropionate], 2,2'-bis(hydroxymethyl)butanoltris[3-(1-aziridinyl)propionate], pentaerythritol tetra[3-(1-aziridinyl)propionate], diphenylmethane-4,4-bis-N,N'-epoxyethylurea, 1,6-hexamethylenebis-N,N'-epoxyethylurea, 2,4,6-(triepoxyethylimino)-triazine, bis[1-(2-ethyl)aziridinyl]benzene-1,3-carboxylic acid amide.

Phenolic hardeners can be phenolic compounds. For example, a phenolic compound can be a phenolic resin having two or more phenolic hydroxyl groups in one molecule, such as one or more of bisphenol A type phenolic resin, bisphenol F type phenolic resin, phenol aralkyl type phenolic resin, dicyclopentadiene type phenolic resin, triphenylmethane type phenolic resin, phenolic varnish type phenolic resin, xylene type phenolic resin, and biphenyl type phenolic resin.

Amine-based curing agents can be amine compounds. Amine compounds can be compounds with two or more amine groups, and can be diamines or other polyamines.

Isocyanate-based hardeners can be isocyanate compounds. Isocyanate compounds can be one or more selected from aromatic polyisocyanates, aliphatic polyisocyanates, and cycloaliphatic polyisocyanates.

Examples of aromatic polyisocyanates include: 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-toluene diisocyanate (toluene diisocyanate, TDI), 2,6-toluene diisocyanate, and 4,4'-diphenylmethane diisocyanate (methylene diphenyl) diisocyanate (MDI), 2,4-diphenylmethane diisocyanate, 4,4'-diisocyanobiphenyl, 3,3'-dimethyl-4,4'-diisocyanobiphenyl, 3,3'-dimethyl-4,4'-diisocyanodiphenylmethane, 1,5-naphthalene diisocyanate, 4,4',4''-triphenylmethane triisocyanate, m-isocyanophenylsulfonyl isocyanate, p-isocyanophenylsulfonyl isocyanate, etc.

Examples of aliphatic polyisocyanates include: ethyl diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), dodecamethylene diisocyanate, 1,6,11-undecane triisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, methyl 2,6-diisocyanatohexanoate, bis(2-isocyanatoethyl) fumarate, bis(2-isocyanatoethyl) carbonate, 2-isocyanatoethyl-2,6-diisocyanatohexanoate, etc.

Examples of alicyclic polyisocyanates include: isophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate (H12-MDI), cyclohexyl diisocyanate, methylcyclohexyl diisocyanate (hydrogenated TDI), bis(2-isocyanoethyl)-4-cyclohexene-1,2-dicarboxylic acid ester, 2,5-norbornane diisocyanate, 2,6-norbornane diisocyanate, etc.

In addition, examples include trimethylolpropane adducts of diisocyanates, biuret esters that react with water, and trimers having an isocyanurate ring.

As a block-type isocyanate compound, any compound containing a block-type isocyanate group in which the isocyanate group is protected by ε-caprolactam or methyl ethyl ketone (MEK) oxime is acceptable, and there is no particular limitation. Specifically, examples include compounds formed by blocking the isocyanate group of a compound containing the isocyanate group with ε-caprolactam, MEK oxime, cyclohexanone oxime, pyrazole, phenol, etc. In particular, hexamethylene diisocyanate trimers with isocyanurate rings, MEK oxime, or pyrazole blocks are highly preferred when used in this embodiment, as they not only maintain stability but also exhibit excellent bonding strength or solder heat resistance to bonding materials such as polyimide or copper.

The metal chelate hardener can be selected from one or more aluminum chelate compounds, titanium chelate compounds, and zirconium chelate compounds. The central metal can be selected from iron, cobalt, indium, etc.

The hardener can be used in the form of 1 to 50 parts by weight, preferably 10 to 40 parts by weight, and more preferably 20 to 30 parts by weight, relative to 100 parts by weight of the thermosetting resin.

By adjusting the amount of hardener, the flowability and viscosity of the first protective layer 32, the second protective layer 34, and the third protective layer 36 can be adjusted. For example, the second protective layer 34 may have the highest content of hardener, the third protective layer 36 may have the second highest content of hardener, and the first protective layer 32 may contain no hardener at all or contain hardener in an amount less than that of the third protective layer 36.

The first protective layer 32, the second protective layer 34, and the third protective layer 36 may further comprise packing material. The packing material is preferably insulating, and may be selected from inorganic packing materials, phosphorus-based packing materials, nitrogen-based packing materials, fluorine-based packing materials, and polymeric packing materials. One or more types of packing materials may be used.

Inorganic fillers that can be used include: silica, hollow silica, porous silica, mica, talc, kaolin, clay, hydrotalcite, wollastonite, anhydrite, silicon nitride, boron nitride, aluminum nitride, calcium hydrogen phosphate, calcium phosphate, glass slides, hydrated glass, calcium titanate, sepiolite, magnesium sulfate, aluminum hydroxide, and magnesium hydroxide. Zirconia, barium hydroxide, calcium hydroxide, titanium oxide, tin oxide, aluminum oxide, magnesium oxide, zirconium oxide, zinc oxide, molybdenum oxide, antimony oxide, nickel oxide, zinc carbonate, magnesium carbonate, calcium carbonate, barium carbonate, zinc borate, aluminum borate, inorganic ion supplements (for example, IXE (registered trademark) manufactured by Toa Synthetic Co., Ltd.).

As phosphorus-based fillers, examples include: melamine phosphate, polymelamine phosphate, guanidine phosphate, polyguanidine phosphate, ammonium phosphate, polyammonium phosphate, ammonium phosphate, ammonium polyphosphate, ammonium polyphosphate, carbamate phosphate, carbamate phosphate, etc. (poly)phosphate compounds, organophosphate compounds, phosphazene compounds, phosphonic acid compounds, aluminum diethylphosphonate, aluminum methylethylphosphonate, aluminum diphenylphosphonate, aluminum ethylbutylphosphonate, aluminum methylbutylphosphonate, aluminum polyvinylphosphonate, etc., phosphine oxide compounds, phosphine compounds, phosphatidine compounds, phosphatamine compounds, etc.

As nitrogen-based fillers, examples include: benzoguanidine, melamine, melamine, melamine, cyanoacetonitrile, melamine cyanurate, cyanuric acid compounds, isocyanuric acid compounds, triazole compounds, tetraazole compounds, diazo compounds, urea, and other nitrogen-based fillers.

Fluorine-based fillers include: polytetrafluoroethylene powder or its modified forms, tetrafluoroethylene-perfluoroalkyl vinyl ether powder, tetrafluoroethylene-ethylene powder, tetrafluoroethylene-hexafluoropropylene powder, tetrafluoroethylene-vinylidene fluoride powder, tetrafluoroethylene-hexafluoropropylene-perfluoroalkyl vinyl ether powder, polychlorotrifluoroethylene powder, chlorotrifluoroethylene-ethylene powder, chlorotrifluoroethylene-vinylidene fluoride powder, polyvinylidene fluoride powder, and polyvinyl fluoride powder.

As polymer fillers, in addition to polyethylene powder, polyacrylate powder, epoxy resin powder, polyamide powder, polyimide powder, polyurethane powder, liquid crystal polymer beads, polysiloxane powder, etc., multilayer core-shell structures using silicone, acrylic acid, styrene-butadiene rubber, butadiene rubber, etc. can also be listed.

The average particle size _D50 of the filler can be 0.01 μm to 100 μm, preferably 0.02 μm to 40 μm, and even more preferably 0.05 μm to 20 μm.

The second protective layer 34 and the third protective layer 36 may contain 0.1 wt% to 30 wt%, preferably 1 wt% to 25 wt%, and more preferably 5 wt% to 20 wt% of filler. By using filler within the aforementioned range, the index X, index Y, and/or index Z (flowability) can be adjusted to a near-appropriate range.

The first protective layer 32 may not contain filler, or even if it does contain filler, it may contain filler at a lower mass concentration than the second protective layer 34 and the third protective layer 36. For example, if the first protective layer 32 contains filler, it may contain 0.01 to 1 part by weight of the thermosetting resin, preferably 0.01 to 0.5 parts by weight, and more preferably 0.01 to 0.1 parts by weight.

As an example, the second protective layer 34 may have the highest filler content, the third protective layer 36 may have the second highest filler content, and the first protective layer 32 may contain no filler at all or contain filler at a mass concentration lower than that of the third protective layer 36.

As a result, although the protective sheet 38 contains filler, the mass concentration of the filler on the second side of the protective sheet 38 is greater than that on the first side. This suppresses the stickiness (adhesion) of the first protective layer 32 (i.e., the first side) and increases flowability. Furthermore, by adjusting the filler amount and/or the amount of hardener in the first protective layer 32, the adhesive force obtained from the probe adhesion test on the first side of the protective sheet 38 can be adjusted to below a specified value. Additionally, by adjusting the filler amount and/or the amount of hardener, the flowability can be easily adjusted to the order of the first protective layer 32, the third protective layer 36, and the second protective layer 34.

Alternatively, as another example, the second protective layer 34 and the third protective layer 36 may contain the same amount of filler, while the first protective layer 32 may contain no filler at all or contain filler at a concentration lower than that of the second and third protective layers 34 and 36. Instead, the third protective layer 36 may have the highest filler content, the second protective layer 34 may have the second highest filler content, and the first protective layer 32 may contain no filler at all or contain filler at a concentration lower than that of the third protective layer 36.

With the protective sheet 38 as a whole, 100% by weight, the filler content can be 0.1% by weight to 30.0% by weight, preferably 1.0% by weight to 9.8% by weight, and more preferably 3.5% by weight to 8.5% by weight. If the filler content of the protective sheet 38 is lower than this range, the flowability becomes too high; if the filler content of the protective sheet 38 is higher than this range, cracks may occur on the protective layer during thermal cycling, potentially causing poor appearance. The filler content in the protective sheet 38 is merely an additional improvement, not a necessary one.

The first protective layer 32, the second protective layer 34, and the third protective layer 36 may further comprise thermoplastic resins. Preferably, the thermoplastic resin is selected from one or more of, for example, polyester, acrylic resins, polyether, carbamate resins, styrene elastomers, polycarbonate, butadiene rubber, polyamide, esteramide resins, polyisoprene, and cellulose. When thermoplastic resins are included, it is preferable that the content of each layer of the first protective layer 32, the second protective layer 34, and/or the third protective layer 36 is set at 5% to 40% by weight.

The first protective layer 32, the second protective layer 34, and the third protective layer 36 may further include additives. For example, as additives, one or more of the following can be used: colorants (such as pigments, dyes, or carbon black, carbon nanotubes, graphene, fullerene, etc.), flame retardants, anti-blocking agents, metal passivators, thickeners, dispersants, silane coupling agents, rust inhibitors, copper inhibitors, reducing agents, antioxidants, adhesive resins, plasticizers, ultraviolet absorbers, defoamers, and leveling agents.

Figure 4 shows another example of the protective sheet 38 of this embodiment. As shown in Figure 4, the protective sheet 38 may only include the first protective layer 32 and the second protective layer 34, and may not include the third protective layer 36. In this case, the structure and materials of the first protective layer 32 and the second protective layer 34 may be as described in the description.

As another example, one or more of the first protective layer 32, the second protective layer 34, and the third protective layer 36 may also be provided in multiple layers. For example, the protective sheet 38 may also have a first protective layer 32, a second protective layer 34, and multiple third protective layers 36 sandwiched between them.

The protective sheet 38 may also include other layers as needed. For example, the protective sheet 38 may also have a release layer that can be peeled off after being attached to the circuit board 10. If a release layer is provided, it may be provided on the upper side of the second protective layer 34 (opposite to the first protective layer 32).

Figure 5 illustrates an example of the manufacturing process of the electronic device package 100 according to this embodiment. The electronic device package 100 can be manufactured by performing at least some of S100 to S300. For ease of explanation, S100 to S300 are described sequentially, but these processes can also be performed in other order, and/or at least some can be performed in parallel.

In step S100, a protective sheet 38 for forming the protective layer 30 is manufactured. The protective sheet 38 may be the protective sheet illustrated in Figures 2 to 4.

The manufacturing method of the protective sheet 38 is not particularly limited. For example, the following methods can be used: the composition obtained by dissolving the thermosetting resin or other material that forms each layer (first protective layer 32, second protective layer 34, third protective layer 36) of the protective sheet 38 in a solvent or the like is sequentially coated and dried to form a laminated structure, or the pre-cured or semi-cured composition is laminated. Examples of coating methods include: gravure coating, matching coating, stencil coating, lip coating, corner wheel coating, squeegee coating, roller coating, squeegee coating, spray coating, stick coating, rotary coating, dip coating, and various printing methods.

Next, in S200, a protective layer 30 formed by the protective sheet 38 is formed on the mounting substrate 12. For example, the mounting substrate 12 is prepared first. The mounting substrate 12 may be a circuit substrate 10 on which electronic devices 20 are mounted. On the mounting substrate 12, the protective sheet 38 manufactured in S100 is arranged such that the first protective layer 32 (first side) faces the side of the electronic device 20.

Figure 6 shows an example of S200 in the process of Figure 5. As shown, the protective sheet 38 can be attached to the mounting substrate 12 with the protective sheet 38 arranged face-to-face with the electronic device 20 on the side of the first protective layer 32.

Alternatively, the protective sheet 38 can be hot-pressed onto the mounting substrate 12 after placement. Hot pressing can cure the uncured or semi-cured thermosetting resins of each protective layer of the protective sheet 38. Here, when the thermosetting resin is completely cured, the protective sheet 38 becomes the protective layer 30. If the protective sheet 38 has a peelable sheet, the peelable sheet can be removed from the protective sheet 38 after hot pressing.

Hot pressing can be performed under reduced pressure or vacuum. This improves the adhesion between the first protective layer 32 and the mounting substrate 12. Hot pressing can be performed at 100°C to 220°C, preferably 120°C to 200°C, more preferably 140°C to 180°C, for 1 minute to 120 minutes, preferably 1 minute to 40 minutes, more preferably 1 minute to 10 minutes, and at a pressure of 0.1 MPa to 10 MPa, preferably 0.5 MPa to 3 MPa, more preferably 1 MPa to 2 MPa. In the case of additional heating, it can be performed under the same temperature conditions as the hot pressing.

If hot pressing is performed, the layers constituting the protective sheet 38 soften before fully hardening and flow to the sides of the connecting components 24, such as the recesses or protrusions at the corners of the circuit board 10 and the electronic devices 20. In particular, the first protective layer 32, which has higher fluidity than the other layers, adequately protects the portions of the material flowing to these areas from forming the protective layer 30. This prevents contact or leakage between the connecting components 24 and other conductors.

On the other hand, the second protective layer 34 and the third protective layer 36, which have lower fluidity, do not move significantly even by hot pressing, thus leaving a certain amount on the entire electronic device 20. In this way, the situation where the thickness of a part of the protective layer 30 (e.g., the corner of the electronic device 20) is insufficient can be eliminated more reliably.

Figure 7 shows an example of a mounting substrate 12 with a protective layer 30 formed. As explained, the protective layer 30 is formed by hardening the protective sheet 38, thus insulating the entire surface of the mounting substrate 12.

Furthermore, the description provides examples of using a protective sheet 38 that does not contain a peeling sheet, but it is not limited to this. For example, a protective sheet 38 with peeling sheets on the side of the second protective layer 34 can be hot-pressed, and the peeling sheets can be peeled off after hot pressing.

Next, in S300, a conductive layer 40 is formed on the protective layer 30. The conductive layer 40 may be formed in part or in whole of the area where the protective layer 30 is formed. The conductive layer 40 may be formed by transferring metal from the metal sheet 46 to the mounting substrate 12.

Figure 8 shows an example of a metal sheet 46. The metal sheet 46 has a metal material layer 44 formed on the peeling sheet 42.

The peeling sheet 42 may be a film-like peeling substrate that can be peeled off later or a cushioning peeling resin. The peeling sheet 42 may include a single layer or multiple layers of peeling substrate and/or peeling resin.

A release substrate is a film-like substrate that has been given release properties on one or both sides. Ideally, a release substrate is a sheet with a tensile fracture strain of less than 50% at 150°C. As a peeling substrate, examples include polyethylene terephthalate, polyethylene naphthalate, polyvinyl fluoride, polyvinylidene fluoride, rigid polyvinyl chloride, polyvinylidene chloride, nylon, polyimide, polystyrene, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polycarbonate, polyacrylonitrile, polybutene, soft polyvinyl chloride, polyvinylidene fluoride, polyethylene, polypropylene, polyurethane resin, ethylene-vinyl acetate copolymer, polyvinyl acetate and other plastic sheets, cellophane, paper, kraft paper, coated paper and other papers, various non-woven fabrics, synthetic paper, metal foil, or composite films composed of these.

The peel resin is a resin that can conform to the shape of electronic devices 20 and also has mold release properties. That is, the peel resin is a resin that allows the mold release cushioning component to be peeled off after hot pressing, etc. Ideally, the peel resin has a tensile breaking strain of 50% or more at 150°C. Furthermore, it is preferable that the peel resin is melted during hot pressing.

As a peelable resin, one or more of the following can be selected: polyethylene, polypropylene, polyethersulfone, polyphenylene sulfide, polystyrene, polymethylpentene, polybutylene terephthalate, cyclic olefin polymers, and silicone. From the viewpoint of balancing embeddability and peelability, polypropylene, polymethylpentene, polybutylene terephthalate, and silicone are particularly preferred.

The metal material layer 44 can be formed from a conductive paste comprising a thermosetting resin and a conductive filler. For example, the metal material layer 44 can be formed by applying the conductive paste to the peel 42 and drying the solvent. The thermosetting resin in the conductive paste is preferably in an uncured or semi-cured state. As a coating method, methods for coating the components of the aforementioned protective layers or methods such as screen printing can be listed.

As a thermosetting resin, the same resin used in the formation of the first to third protective layers can be used.

As conductive fillers, examples include: metal particles, carbon particles, and conductive resin particles. Conductive fillers may contain metal particles as an essential component, and may also include one or more other components such as carbon particles.

Examples of metal particles include gold, platinum, silver, copper, nickel, aluminum, iron, or alloys thereof, but copper is preferred in terms of price and conductivity. Furthermore, the metal particles can be particles comprising a metal-containing core and a coating layer covering the core and containing a metal different from the core. The metals listed above can be used as the core and coating layer. For example, silver-coated copper particles having a copper-containing core and a silver-containing coating layer can be cited.

As carbon particles, examples include one or more of acetylene black, Ketjen black, furnace black, carbon nanotubes, carbon nanofibers, graphite, fullerene, carbon nanowalls, and graphene. As conductive resin particles, examples include one or more of poly(3,4-ethylenedioxythiophene), polyacetylene, and polythiophene.

The average particle size _D50 of the conductive filler is preferably about 1 μm to 100 μm, more preferably about 3 μm to 75 μm, and even more preferably about 5 μm to 50 μm. The average particle size of the conductive filler can be determined by laser diffraction or scattering methods, for example, the average diameter of a circle whose projected area is equal to that of the filler particle aggregate can be used as the average particle size. By setting the average particle size of the conductive filler within the aforementioned range, the electromagnetic wave shielding effect of the subsequently formed conductive layer 40 can be further improved. In addition, for example, the good flowability when mixed with thermosetting resin improves the formability of the conductive layer 40.

The conductive filler can be any shape, such as spherical, needle-like, scale-like, plate-like, branch-like, grape-like, fibrous, or plate-like. The content of the conductive filler in the metal layer 44 is not particularly limited, but is preferably 100 to 1500 parts by weight relative to 100 parts by weight of the thermosetting resin, and more preferably 100 to 1000 parts by weight. This allows the conductive layer 40 to be endowed with necessary and sufficient conductivity, regardless of the type of conductive particles, and significantly improves the electromagnetic wave shielding effect. Furthermore, it is also preferable to improve the flowability of the composition containing the thermosetting resin and the conductive filler, making it easier to form the metal layer 44.

The metal layer 44 may further comprise a thermoplastic resin. The same thermoplastic resin that can be used in the first to third protective layers may be used.

The metal layer 44 may contain other additives. For example, one or more of the following additives may be used: crosslinking agents, colorants, flame retardants, fillers, lubricants, anti-blocking agents, metal passivators, thickeners, dispersants, silane coupling agents, rust inhibitors, copper toxicity inhibitors, reducing agents, antioxidants, adhesive resins, plasticizers, ultraviolet absorbers, defoamers, and leveling agents.

As crosslinking agents, compounds that undergo crosslinking reactions with the functional groups of thermosetting resins can be listed. For example, one or more of the following can be used as crosslinking agents: phenolic curing agents, amine curing agents, isocyanate curing agents, epoxy curing agents, aziridine curing agents, and metal chelate curing agents.

As a colorant, one or more of the following can be used: organic pigments, carbon black, ultramarine, red iron oxide, zinc oxide, titanium oxide, graphite, and dyes. As a flame retardant, one or more of the following can be used: halogenated flame retardants, phosphorus-containing flame retardants, nitrogen-containing flame retardants, and inorganic flame retardants. As a filler, one or more of the following can be used: glass fiber, silica, talc, and ceramics.

As a lubricant, one or more of the following can be used: fatty acid esters, hydrocarbon resins, paraffin, higher fatty acids, fatty acid amides, aliphatic alcohols, metal soaps, and modified silicones. As an anti-blocking agent, one or more of the following can be used: calcium carbonate, silicon dioxide, polymethylsilsesquioxane, and aluminum silicates.

Furthermore, the metal material layer 44 can be a metal foil. In this case, the metal foil can be formed on the peel sheet 42 by plating or the like, with the same metal as the metal exemplified in the conductive filler.

Figure 9 shows an example of S300 using a metal sheet 46. As shown, the metal material layer 44 containing the metal sheet 46 is disposed and attached to the protective layer 30. Next, the thermosetting resin of the metal material layer 44 is cured by hot pressing the metal sheet 46, thereby forming a conductive layer 40. Afterward, the peeling sheet 42 is removed. In this way, the electronic device package 100 shown in Figure 1 is manufactured.

Hot pressing can be performed under reduced pressure or vacuum. This improves the adhesion between the metal material layer 44 and the mounting substrate 12. Hot pressing can be performed at 100°C to 220°C (preferably 120°C to 180°C) for 1 minute to 120 minutes (preferably 1 minute to 60 minutes) and at 0.1 MPa to 10 MPa (preferably 0.5 MPa to 3 MPa).

Furthermore, in S300, the conductive layer 40 can be formed by other methods instead of using the metal sheet 46. For example, the conductive layer 40 can be formed by depositing metal using plating, vapor deposition, or sputtering (hereinafter also referred to as "plating, etc."). Examples of metals used for plating, etc., include gold, platinum, silver, copper, nickel, aluminum, iron, or alloys thereof. As another example, the conductive layer 40 can be formed by applying or spraying conductive paste (e.g., applicable to the metal material layer 44) onto the protective layer 30 or the second protective layer 34 (before hot pressing) and then hardening it.

Following S300, the electronic device package 100 can be monolithically processed as needed. For example, the electronic device package 100 can be cut in the X and Y directions at locations corresponding to the product area to obtain individual products. Alternatively, without performing S300, an electronic device package 100 without the conductive layer 40 can be used.

As described above, in this embodiment, a protective layer 30 is formed on the mounting substrate 12 using a protective sheet 38 with a specified structure and physical properties through processes S100 to S300. This ensures that the protective layer 30 is formed to a sufficient thickness in areas such as corners of electronic devices 20 where excessive flow could lead to thinning of the film, or in areas where sufficient flow is not possible. Furthermore, this embodiment also prevents liquid from pooling on the first side of the protective sheet 38 when it is attached to the circuit substrate 10.

The protective layer 30 may include a layer structure derived from the protective sheet 38. For example, if the protective sheet 38 has a three-layer structure, at least a portion of the protective layer 30 may have a three-layer structure derived from each of the first protective layer 32 to the third protective layer 36. In particular, in the corner recesses where the circuit substrate 10 contacts the electronic device 20, the film thickness of the protective layer 30 increases, and the layer structure of the protective sheet 38 is easily retained. On the other hand, in the corners of the electronic device 20, where the film thickness of the protective layer 30 decreases, the layer structure of the protective sheet 38 may not be retained.

The following examples illustrate this embodiment.

[Example] [Composition A1 for First Protective Layer] Composition A1 for preparing a first protective layer 32 having the following composition: Polyurethane resin (acid value: 5 mgKOH/g, weight average molecular weight: 54,000, Tg: -7℃, manufactured by Toyo Chemical Co., Ltd.) 100 parts by weight of epoxy compound (manufactured by Nippon Steel Chemical & Material Co., Ltd. YDF-2005RD) 20 parts by weight of solvent (methyl ethyl ketone) 20 parts by weight

[Composition A2 for First Protective Layer] Except for adding 6 parts by weight of silicon dioxide (SO-C6, D ₅₀ ; 2.0 μm manufactured by Admatechs), composition A2 for a first protective layer 32 having the same composition as composition A1 is prepared.

[Composition A3 for First Protective Layer] Except for adding 12 parts by weight of silicon dioxide (SO-C6, D ₅₀ ; 2.0 μm manufactured by Admatechs), composition A3 for a first protective layer 32 having the same composition as composition A1 is prepared.

[Composition A4 for First Protective Layer] Except for adding 15 parts by weight of silicon dioxide (SO-C6, D ₅₀ ; 2.0 μm manufactured by Admatechs), composition A4 for a first protective layer 32 having the same composition as composition A1 is prepared.

[Composition A5 for First Protective Layer] Except for adding 55 parts by weight of silicon dioxide (SO-C6, D ₅₀ ; 2.0 μm manufactured by Admatechs), composition A5 for a first protective layer 32 having the same composition as composition A1 is prepared.

[Composition A6 for First Protective Layer] Except for adding 1.5 parts by weight of silicon dioxide (SO-C6 manufactured by Admatechs, D ₅₀ ; 2.0 μm), composition A6 for a first protective layer 32 having the same composition as composition A1 is prepared.

[Composition A7 for First Protective Layer] Except for adding 20 parts by weight of silicon dioxide (SO-C6, D ₅₀ ; 2.0 μm manufactured by Admatechs), composition A7 for a first protective layer 32 having the same composition as composition A1 is prepared.

[Component B1 for Second Protective Layer] Component B1 is prepared for use in the preparation of a second protective layer 34 having the following composition: Polyurethane resin (acid value: 5 mgKOH/g, weight average molecular weight: 54,000, Tg: -7℃, manufactured by TOYO CHEM) 100 parts by weight of epoxy compound (YDF-2001 manufactured by NIPPON STEEL Chemical & Material Co., Ltd.) 20 parts by weight of silicon dioxide (SO-C6, D ₅₀ ; 2.0 μm manufactured by Admatechs Co., Ltd.) 13.6 parts by weight (10% by weight of solids after removing solvent) of solvent (methyl ethyl ketone) 20 parts by weight

[Composition B2 for the second protective layer] except that 24.4 parts by weight of silicon dioxide is replaced with talc (FH104 D ₅₀ ; 4.0 μm manufactured by Fuji Talc Co., Ltd.), composition B2 is prepared to have the same composition as composition B1 for the second protective layer 34.

[Composition B3 for Second Protective Layer] Composition B3 is used to prepare a second protective layer 34 having the same composition as composition B1, except that the content of silicon dioxide is changed to 35.0 parts by weight.

[Composition B4 for Second Protective Layer] Composition B4 is used to prepare a second protective layer 34 having the same composition as composition B1, except that no silicon dioxide is added at all.

[Composition B5 for Second Protective Layer] Composition B5 for a second protective layer 34 having the same composition as composition B1 is prepared except that the content of silicon dioxide (SO-C6, D ₅₀ ; 2.0 μm manufactured by Admatechs) is changed to 0.10 parts by weight.

[Composition B6 for Second Protective Layer] Composition B6 for a second protective layer 34 having the same composition as composition B1 is prepared except that the content of silicon dioxide (SO-C6, D ₅₀ ; 2.0 μm, manufactured by Admatechs) is changed to 0.15 parts by weight.

[Composition B7 for Second Protective Layer] Composition B7 for a second protective layer 34 having the same composition as composition B1 is prepared except that the content of silicon dioxide (SO-C6, D ₅₀ ; 2.0 μm manufactured by Admatechs) is changed to 55 parts by weight.

[Composition B8 for Second Protective Layer] Composition B8 for a second protective layer 34 having the same composition as composition B1 is prepared except that the content of silicon dioxide (SO-C6, D ₅₀ ; 2.0 μm manufactured by Admatechs) is changed to 20 parts by weight.

[Composition B9 for Second Protective Layer] Composition B9 for a second protective layer 34 having the same composition as composition B1 is prepared except that the content of silicon dioxide (SO-C6, D ₅₀ ; 2.0 μm manufactured by Admatechs) is changed to 15 parts by weight.

[Composition B10 for Second Protective Layer] Composition B10 for a second protective layer 34 having the same composition as composition B1 is prepared except that the content of silicon dioxide (SO-C6, D ₅₀ ; 2.0 μm manufactured by Admatechs) is changed to 1.5 parts by weight.

[Composition C1 for Third Protective Layer] Composition C1 for the preparation of a third protective layer 36 having the following composition: Polyurethane resin (acid value: 5 mgKOH/g, weight average molecular weight: 54,000, Tg: -7℃, manufactured by TOYO CHEM) 100 parts by weight of epoxy compound (YDF-170 manufactured by NIPPON STEEL Chemical & Material Co., Ltd.) 20 parts by weight of silica (SO-C6, D ₅₀ ; 2.0 μm manufactured by Admatechs Co., Ltd.) 13.6 parts by weight of solvent (methyl ethyl ketone) 20 parts by weight of [Composition C2 for Third Protective Layer] Composition C2 for the preparation of a third protective layer 36 having the same composition as composition C1, except that silica is not added at all. [Composition C3 for Third Protective Layer] Composition C3 for a third protective layer 36 is prepared, except that the content of silicon dioxide (SO-C6, D ₅₀ ; 2.0 μm, manufactured by Admatechs) is changed to 1.5 parts by weight. [Composition C4 for Third Protective Layer] Composition C4 for a third protective layer 36 is prepared, except that the content of silicon dioxide (SO-C6, D ₅₀ ; 2.0 μm, manufactured by Admatechs) is changed to 20 parts by weight. [Composition C5 for Third Protective Layer] Composition C5 for a third protective layer 36 is prepared, except that the content of silicon dioxide (SO-C6, D ₅₀ ; 2.0 μm, manufactured by Admatechs) is changed to 15 parts by weight. [Composition C6 for Third Protective Layer] Composition C6 for a third protective layer 36 is prepared, except that the content of silicon dioxide (SO-C6, D ₅₀ ; 2.0 μm, manufactured by Admatechs) is changed to 55 parts by weight.

[Fabrication of monolayer A1] Composition A1 is coated onto a peeling sheet. Subsequently, it is heated at 120°C for 5 minutes to dry and semi-cur it, forming a monolayer A1 with a film thickness of 15 μm corresponding to the first protective layer 32.

[Preparation of monolayer B1] Composition B1 was coated onto a peel sheet. Subsequently, it was heated at 120°C for 5 minutes to dry and semi-cured, forming a monolayer B1 with a film thickness of 45 μm corresponding to the second protective layer 34.

[Fabrication of monolayer C1] The composition C1 was coated onto a peel sheet. Subsequently, it was heated at 120°C for 5 minutes to dry and semi-cured, forming a monolayer C1 with a film thickness of 60 μm corresponding to the third protective layer 36.

[Manufacturing of Protective Sheet H1] Composition A1 is coated onto a peeling sheet. Then, it is heated at 120°C for 5 minutes to dry and semi-cur, forming a first protective layer 32 with a film thickness of 15 μm. Composition C1 is coated onto the first protective layer 32. Then, it is heated at 120°C for 5 minutes to dry and semi-cur, forming a third protective layer 36 with a film thickness of 60 μm. Then, composition B1 is coated onto the third protective layer 36. Then, it is heated at 120°C for 5 minutes to dry and semi-cur, forming a second protective layer 34 with a film thickness of 45 μm. Thus, a protective sheet H1 comprising the first protective layer 32, the third protective layer 36, and the second protective layer 34 is formed.

[Manufacturing of Protective Sheet H2] Except that component B2 is used instead of component B1, protective sheet H2 is manufactured using the same method as protective sheet H1.

[Manufacturing of Protective Sheet H3] Except that component B3 is used instead of component B1, protective sheet H3 is manufactured using the same method as protective sheet H1.

[Manufacturing of Protective Sheet H4] Except that component B4 is used instead of component B1, protective sheet H4 is manufactured using the same method as protective sheet H1.

[Manufacturing of Protective Sheet H5] Except that component B5 is used instead of component B1, protective sheet H5 is manufactured using the same method as protective sheet H1.

[Manufacturing of Protective Sheet H6] Except that component B6 is used instead of component B1, protective sheet H6 is manufactured using the same method as protective sheet H1.

[Manufacturing of Protective Sheet H7] Except for using component A5 instead of component A1, component B7 instead of component B1, and component C6 instead of component C1, protective sheet H7 is manufactured using the same method as protective sheet H1.

[Manufacturing of Protective Sheet H8] Except that component A2 is used instead of component A1, protective sheet H8 is manufactured using the same method as protective sheet H1.

[Manufacturing of Protective Sheet H9] Except that component A3 is used instead of component A1, protective sheet H9 is manufactured using the same method as protective sheet H1.

[Manufacturing of Protective Sheet H10] Except that component A4 is used instead of component A1, protective sheet H10 is manufactured by the same method as protective sheet H1.

[Manufacturing of Protective Sheet H11] Except that component B4 is used instead of component B1 and component C2 is used instead of component C1, protective sheet H11 is manufactured by the same method as protective sheet H1.

[Manufacturing of Protective Sheet H12] Except that component A6 is used instead of component A1, component B10 is used instead of component B1, and component C3 is used instead of component C1, protective sheet H12 is manufactured by the same method as protective sheet H1.

[Manufacturing of Protective Sheet H13] Except that component A7 is used instead of component A1, component B8 is used instead of component B1, and component C4 is used instead of component C1, protective sheet H13 is manufactured using the same method as protective sheet H1.

[Manufacturing of Protective Sheet H14] Except that component A4 is used instead of component A1, component B9 is used instead of component B1, and component C5 is used instead of component C1, protective sheet H14 is manufactured using the same method as protective sheet H1.

The following tests/evaluations were conducted on single-layer A1 to single-layer A7, single-layer B1 to single-layer B10, single-layer C1 to single-layer C6, and protective plates H1 to protective plates H14.

[Glass transition temperature] The glass transition temperature of each layer was measured, and the results were: single layer A1: 42℃, single layer B1: 22℃, and single layer C1: 27℃.

[Flow Length] Polyimide films (Capton 500H) are laminated on one side of each of the monolayers A1 to C1 and the protective sheets H1 to H14 at a heating rate of 2 m/min under a heating condition of 90°C, and stamped into rectangles of 0.5 cm × 1 cm. After lamination, the release liner is peeled off and placed on the polyimide film (Capton 500H). In this way, monolayers A1 to C1 and the protective sheets H1 to H14 are each sandwiched between two polyimide films.

A heat-resistant release film (Opulent CR1012MT4 150 μm, manufactured by Mitsui Chemicals Tohcello) was placed on each of the monolayers A1 to C1 and protective sheets H1 to H14, which were held between polyimide films. These were held in place using silicone rubber with a rubber hardness of 70 degrees (measured using a JIS K 6253 A, TECLOCK rubber/plastic hardness tester GS-719N). The mixture was heated to 180°C and pressed at 1 MPa for 5 minutes. The length of the most fluid portion flowing from each side of the polyimide film after melting was calculated, and the average value of the four sides was used as the flow length (μm). Four samples were prepared for each of the monolayers A1 to C1 and the protective sheets H1 to H14, and the average flow length (μm) was measured. In addition, based on the measured average flow length (μm) and film thickness (μm), the exponents X, Z, Y, and W were calculated.

[Hot and Cold Cycling] (Preparation of Test Substrates) A substrate containing glass epoxy is prepared with 5 x 5 molded and sealed electronic components (1000 μm x 1000 μm) arranged in an array. The substrate thickness is 0.3 mm, and the molding seal thickness, i.e., the height (part height) H from the top surface of the substrate to the top surface of the molding seal material, is 0.7 mm. Subsequently, a half-cut is made along the grooves that serve as gaps between the parts to obtain the test substrate. The half-cut groove depth is set to 0.8 mm (the groove depth of substrate 20 is 0.1 mm), and the half-cut groove width is set to 200 μm. Under conditions of 8 MPa and 170°C, protective sheets H1 to H14 are hot-pressed onto the test substrate for 5 minutes, and the cushioning material is peeled off by hand. Subsequently, the obtained electronic component mounting substrate was fully cut along the half-cut groove to obtain 25 test pieces for each protective layer. The obtained test pieces were then subjected to 1000 alternating exposures under thermal shock conditions ("TSE-11-A", manufactured by Espec) at high temperature (125°C for 15 minutes) and low temperature (-50°C for 15 minutes). Afterwards, the test pieces were removed, the appearance of the electronic component protective layer was observed, and the number of damaged test pieces was counted and evaluated according to the following criteria. For each case, the number of tests was set to 10. +++: 0 damaged test pieces. ++: 1 to 2 damaged test pieces. +: The number of broken test pieces is 3 to 5. (Practical standard) NG: The number of broken test pieces is 6 or more. [Table 1A] Single layer A1 Single-layer A2 Single-layer A3 Single-layer A4 Single-layer A5 Single-layer A6 Single-layer A7 Flow length 113 μm 91 μm 84 μm 73 μm 28 μm 109 μm 69 μm Film thickness 15 μm 15 μm 15 μm 15 μm 15 μm 15 μm 15 μm Index Z=7.53 Z=6.07 Z=5.60 Z=4.87 Z=1.87 Z=7.27 Z=4.60 [Table 1B] Single layer B1 Single-layer B2 Single-layer B3 Single-layer B4 Single-layer B5 Single-layer B6 Single layer B7 Single layer B8 Single-layer B9 Single-layer B10 Flow length 48 μm 60 μm 58 μm 111 μm 96 μm 88 μm 29 μm 61 μm 62 μm 105 μm Film thickness 60 μm 60 μm 60 μm 60 μm 60 μm 60 μm 60 μm 60 μm 60 μm 60 μm Index Y=0.80 Y=1.00 Y=0.97 Y=1.85 Y=1.60 Y=1.47 Y=0.48 Y=1.02 Y=1.03 Y=1.75 [Table 1C] Single layer C1 Single layer C2 Single layer C3 Single-layer C4 Single-layer C5 Single-layer C6 Flow length 64 μm 142 μm 131 μm 81 μm 79 μm 40 μm Film thickness 45 μm 45 μm 45 μm 45 μm 45 μm 45 μm Index W=1.42 W=3.16 W=2.91 W=1.80 W=1.76 W=0.89 [Table 2A] Protective film H1 Protective film H2 Protective film H3 Protective film H4 Protective Film H5 Protective film H6 Protective film H7 Flow length 106 μm 79 μm 80 μm 123 μm 119 μm 120 μm 42 μm Film thickness 120 μm 120 μm 120 μm 120 μm 120 μm 120 μm 120 μm Index X=0.88 X=0.66 X=0.67 X=1.03 X=0.99 X=1.00 X=0.35 The total weight of the filler 7.00% 9.50% 11.90% 3.60% 3.70% 3.70% 31% Hot and cold circulation +++ ++ + +++ +++ +++ + [Table 2B] Protective film H8 Protective film H9 Protective film H10 Protective film H11 Protective film H12 Protective film H13 Protective film H14 Flow length 90 μm 80 μm 85 μm 252 μm 231 μm 58 μm 63 μm Film thickness 120 μm 120 μm 120 μm 120 μm 120 μm 120 μm 120 μm Index X=0.75 X=0.67 X=0.71 X=2.10 X=1.93 X=0.48 X=0.35 The total weight of the filler 8.40% 9.80% 10.50% 0.00% 1.20% 14.30% 11.10% Hot and cold circulation +++ ++ + +++ +++ + +

[Probe Adhesion Test] Protective sheets H1 to H10 were used for the probe adhesion test. Protective sheets H1 to H10 were cut into pieces of at least 2 cm square for testing, according to Section 6.12 Adhesion Test Method 3.4 of the General Test Method of the Seventeenth Amendment to the Japanese Pharmacopoeia. The test was conducted by attaching the sheets to a counterweight ring and placing a total weight of 200 g on top of it. The test was performed with N=4, and the average value was taken as the result. The results are shown below. [Table 3A] Unit: N/ ^cm² Protective film H1 Protective film H2 Protective film H3 Protective film H4 Protective Film H5 Protective film H6 Protective film H7 First side 0.01 0.01 0 0.01 0.01 0.01 0 Second side 0.09 0.14 0.26 0.01 0.03 0.05 0.28 [Table 3B] Unit: N/ ^cm² Protective film H8 Protective film H9 Protective film H10 Protective film H11 Protective film H12 Protective film H13 Protective film H14 First side 0.01 0.01 0 0.01 0.01 0.01 0.01 Second side 0.09 0.09 0.09 0.09 0.09 0.09 0.09

As shown in the figure, there is almost no tackiness on the side of the first protective layer 32 (first surface side). On the other hand, the tackiness is increased on the side of the second protective layer 34 (second surface side) depending on the amount of filler (silica).

[Manufacturing of Electronic Device Packages] A mounting substrate containing an IC chip connected to a circuit board via bumps and an octagonal inductor is prepared. With the first protective layer side facing the circuit board side, the protective sheet H1 is hot-pressed at 180°C and 1 MPa for 5 minutes to manufacture an electronic device package P1 with a protective layer. Electronic device packages P2 to P14 are manufactured from protective sheets H2 to H14 using the same method. Regarding electronic device packages P7, P11, and P13 (excluding electronic device packages P1 to P14, satisfying index X = 0.5 to 2.0), it was confirmed that each protective layer is formed with a thickness of 15 μm or more on any of the following surfaces: the side of the bump, the side of the inductor, or the upper corner of the IC chip, providing sufficient insulation protection. However, in P11 (index X > 2.0), the protective layer has excessively high fluidity, resulting in areas with thinner film thickness. Furthermore, in P7 and P13 (index X < 0.5), the protective layer has insufficient fluidity, resulting in areas where the protective layer cannot be fully distributed. In addition, the results of the thermal cycling test for protective sheets of H3, H7, H10, H13 and H14 with a filler content of 10 parts by weight or more were worse than those for other protective sheets.

The present invention has been described above using embodiments, but the scope of the present invention is not limited to the scope described in the embodiments. It will be apparent to those skilled in the art that various modifications or alterations can be made to the embodiments. As expressly stated in the patent application, such modified or altered embodiments may also be included within the scope of the present invention.

The execution order of actions, procedures, steps, and stages in the methods shown in the patent application, specification, and drawings is not specifically indicated as "before" or "before". Furthermore, it should be noted that as long as the results of previous processes are not used in subsequent processes, they can be implemented in any order. Even if terms such as "firstly" or "next" are used for convenience in the description of the action flow in the patent application, specification, and drawings, it does not mean that they must be implemented in a specific order.

10: Circuit board 12: Mounting board 20: Electronic device (board) 22: Electronic device 24: Connector 30: Protective layer 32: First protective layer 34: Second protective layer 35: Polyimide film 36: Third protective layer 38: Protective sheet 40: Conductive layer 42: Peel-off sheet 44: Metal material layer 46: Metal sheet 100: Electronic device packaging L1～L4: Length (flow length) S100, S200, S300: Steps

Figure 1 shows an example of the electronic device package 100 of this embodiment. Figure 2 shows an example of the protective sheet 38 of this embodiment. Figure 3 shows an example of the flow path of this embodiment. Figure 4 shows another example of the protective sheet 38 of this embodiment. Figure 5 shows an example of the manufacturing method flow of the electronic device package 100 of this embodiment. Figure 6 shows an example of S200 in the flow of Figure 5. Figure 7 shows an example of the mounting substrate 12 with the protective layer 30 formed. Figure 8 shows an example of the metal sheet 46. Figure 9 shows an example of S300 using the metal sheet 46.

10: Circuit board; 20: Electronic device; 22: Electronic device; 24: Connector; 30: Protective layer; 40: Conductive layer; 100: Electronic device package.

Claims (17)

A protective sheet for use on a circuit board, the protective sheet having a first side and a second side opposite to the first side, wherein the adhesive force of the first side obtained by probe adhesion test is less than 0.15 N/cm ² , and the index X calculated by Equation 1 below is 0.75 to 1.93, the protective sheet contains filler at a content of 1.0% to 8.5% by weight, [Equation 1] X = F _total / T _total ; F _total : the average value in μm of the flow length of the four sides of the most flowable part of each side when the protective sheet, which is made into a rectangle of 0.5 cm × 1.0 cm, is heated and pressed at 180°C and 1 MPa for 5 minutes, T _total : the total thickness of the protective sheet in μm. The protective sheet as described in claim 1, wherein the tensile breaking strength is 10 N/ ^mm² to 70 N/ ^mm² . The protective sheet as claimed in claim 1, wherein the protective sheet comprises: a first protective layer; and a second protective layer, the first protective layer being the outermost layer on the first side of the protective sheet, and the second protective layer being the outermost layer on the second side of the protective sheet. The protective sheet as described in claim 3, wherein the index Y of the second protective layer, calculated by the following formula 2, is 0.5 to 1.5, [Formula 2] Y = F ₂ / T ₂ F ₂ ; the average value in μm of the flow length of the four sides of the most flowable portion of each side when the second protective layer, which is made into a rectangle of 0.5 cm × 1.0 cm, is heated and pressed at 180°C and 1 MPa for 5 minutes, T ₂ ; and the thickness of the second protective layer in μm. The protective sheet as described in claim 3, wherein the index Z of the first protective layer, calculated by the following formula 3, is 2.0 to 15.0, [Formula 3] Z = F ₁ / T ₁ F ₁ ; the average value in μm of the flow length of the four sides of the most flowable portion of each side when the first protective layer, which is made into a rectangle of 0.5 cm × 1.0 cm, is heated and pressed at 180°C and 1 MPa for 5 minutes, T ₁ ; the thickness of the first protective layer in μm. The protective sheet as described in claim 3, wherein the glass transition temperature of the second protective layer is below 60°C. The protective sheet as described in claim 3, wherein the thickness of the first protective layer is 5 μm to 150 μm, and the thickness of the second protective layer is 10 μm to 200 μm. The protective sheet as described in claim 3, wherein a third protective layer is included between the first protective layer and the second protective layer. The protective sheet as described in claim 8, wherein the index W of the third protective layer, calculated by the following formula 4, is 1.0 to 3.0, [Formula 4] W = F ₃ / T ₃ F ₃ ; when the third protective layer, which is made into a rectangle of 0.5 cm × 1.0 cm, is heated and pressed at 180°C and 1 MPa for 5 minutes, the average value in μm of the flow length of the four sides of the most flowable part on each side, T ₃ ; the thickness of the third protective layer in μm. The protective sheet as described in claim 8, wherein the thickness of the third protective layer is 20 μm to 200 μm. The protective sheet as described in claim 8, wherein the first protective layer, the second protective layer and the third protective layer comprise polyurethane resin and a hardener. The protective sheet as claimed in claim 1, wherein the protective sheet comprises filler, and the mass concentration of the filler on the second side of the protective sheet is greater than that on the first side. The protective sheet as described in claim 1, wherein the protective sheet comprises: a first protective layer; and a second protective layer, wherein the first protective layer has a film thickness of 10 μm to 30 μm and is the outermost layer on the first side of the protective sheet, and the second protective layer has a film thickness of 50 μm to 100 μm and is the outermost layer on the second side of the protective sheet. The protective sheet as described in claim 1, wherein the protective sheet comprises: a first protective layer; and a second protective layer, wherein the first protective layer has a film thickness of 10 μm to 30 μm and a glass transition temperature of 20°C to 50°C, and is the outermost layer on the first side of the protective sheet; and the second protective layer has a film thickness of 50 μm to 100 μm and a glass transition temperature of 10°C to 40°C, and is the outermost layer on the second side of the protective sheet. A method for manufacturing an electronic device package includes the following steps: mounting an electronic device on a substrate on a substrate having conductive circuits on its surface; arranging a protective sheet as described in any one of claims 1 to 14 with its first surface facing the electronic device side; and forming a protective layer formed by the protective sheet on the mounting substrate. The method of manufacturing an electronic device package as described in claim 15, wherein the step of forming the protective layer includes hot-pressing the protective sheet onto the mounting substrate after it has been disposed. The method of manufacturing an electronic device package as described in claim 15 further includes the step of forming a conductive layer on the protective layer.