TWI483830B - A method for manufacturing a resin sheet for packaging - Google Patents

Description

Method for producing resin sheet for encapsulation

The present invention relates to a method for producing a resin sheet for encapsulation for insulating and encapsulating a plurality of electronic components mounted on a substrate.

An electronic component module in which a plurality of electronic components are mounted on a substrate is formed with an encapsulating resin layer so as to cover the substrate and the electronic component in order to protect the electronic component from moisture and external contact. The encapsulating resin layer is formed by placing a resin sheet for encapsulation in a semi-hardened state (B stage) on a substrate on which an electronic component is mounted, and heating and pressing the resin sheet for encapsulation placed thereon.

10(A) to 10(C) are views showing a general example of manufacturing the electronic component module 200 using the resin sheet for packaging 205. As shown in FIG. 10(A), a circuit pattern 202 is formed on the circuit board 201, and the electronic component 204 is mounted on the circuit pattern 202 via the conductive adhesive 203.

As shown in FIG. 10(B), the encapsulating resin sheet 205 is placed above the circuit board 201 on which the electronic component 204 is mounted. Then, the circuit board 201 and the encapsulating resin sheet 205 are sandwiched by the two flat plates 206, and the encapsulating resin sheet 205 is heated and pressed. Thereby, the electronic component 204 is embedded in the encapsulating resin sheet 205, and the encapsulating resin sheet 205 is cured by heating to form the encapsulating resin layer 209.

The electronic component module 200 manufactured by the above process is shown in FIG. 10(C), and the electronic component 204 and the circuit board 201 are covered by the cured encapsulating resin layer 209 and packaged.

The description of the manufacturing process of the electronic component module 200 has been made so far. Following, on electronics A method of manufacturing the encapsulating resin sheet 205 used in the manufacturing process of the part module 200 will be described.

The method of producing the resin sheet 205 for encapsulation is described in, for example, Patent Document 1 (Japanese Patent Laid-Open Publication No. 2009-29930). According to Patent Document 1, the liquid resin composition 102 is applied onto the upper surface of the support film 103 by the coating device 101 shown in Fig. 11, and the release film 105 which is successively fed from the release film roll 104 is superposed on the surface. The upper surface of the resin composition 102 is pressed against the resin composition 102 by the pressing roller 106, whereby the encapsulating resin sheet 205 is produced.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2009-29930

However, in the method of manufacturing the encapsulating resin sheet 205 described in Patent Document 1, since the expensive equipment such as the coating device 101, the release film roll 104, and the pressing roller 106 is required, the resin sheet for encapsulation 205 is used. The problem of higher manufacturing costs.

Further, in the method of applying the liquid resin composition 102 to the upper surface of the support film 103 as described in Patent Document 1, since the liquid resin composition 102 is wet-diffused, it is difficult to manufacture a package having a large thickness. Resin sheet 205.

Further, in the method for producing a liquid resin composition 102 on the surface of the support film 103 and superimposing the release film 105 as described in Patent Document 1, the resin composition 102 is entrained at the time of coating. Air bubbles are sealed between the support film 103 and the release film 105. From the viewpoint of moisture resistance and external barrier properties, it is preferable that bubbles are not mixed in the encapsulating resin layer 209 of the electronic component module 200. For this reason, it is preferable that the resin sheet 205 for encapsulation used in the manufacturing process of the electronic component module 200 has a small amount of air bubbles. However, in the manufacturing method described in Patent Document 1, air bubbles remain in the resin composition 102. The internal situation.

The problem to be solved by the present invention is to reduce the problems associated with the above-described method of manufacturing the resin sheet for encapsulation 205.

The present invention relates to a method for producing a resin sheet for encapsulation, which is a method for producing a resin sheet for encapsulation which insulates a plurality of electronic components mounted on a substrate, and includes the following steps: a resin body disposing step, The resin body in a semi-hardened state in which the material of the resin sheet for encapsulation is disposed is disposed in a space surrounded by the pair of pressing plates and the side plates provided on the outer peripheral side of the pressing plate; and an extending step of which The vacuum is formed in the enclosed space, and the resin body is heated at a temperature lower than the hardening temperature of the resin body, and the resin body is pressed by the pressing plate at a pressing speed of 0.004 mm/sec or more and 0.06 mm/sec or less. And let it extend.

Preferably, in the resin body disposing step, a protective film subjected to a release treatment is inserted between the resin body and the pressing plate, and in the extending step, the resin body is pressed to extend over the protective film.

Alternatively, it is preferable to perform a mold release treatment on the pressing plate, and in the extending step, the resin body is pressed to extend in the direction of the surface of the pressing plate.

According to the present invention, it is possible to inexpensively manufacture a resin sheet for encapsulation having a large film thickness without expensive equipment. Moreover, the residual of the bubble inside the resin sheet for encapsulation can be suppressed.

11, 205‧‧‧Packaging resin sheet

12‧‧‧Protective film

20‧‧‧Mold

21‧‧‧Liquid resin

22‧‧‧ resin body

23, 25‧‧‧ Press plate

24‧‧‧ side panels

26‧‧‧ Space

30‧‧‧ Pressing device

31‧‧‧ under pressure plate

32‧‧‧ Pressurized plate

33‧‧‧heater

34‧‧‧Pressure servo

35‧‧‧Base plate

36‧‧‧ top board

37‧‧‧ pillar

38‧‧‧vacuum mechanism

101‧‧‧ Coating device

102‧‧‧Resin composition

103‧‧‧Support film

104‧‧‧ release film roll

105‧‧‧ release film

106‧‧‧Press roller

200‧‧‧Electronic parts module

201‧‧‧ circuit board

202‧‧‧ circuit pattern

203‧‧‧Electrical adhesive

204‧‧‧Electronic parts

206‧‧‧ tablet

209‧‧‧Encapsulated resin layer

B‧‧‧ bubble

E‧‧‧arrow

W‧‧‧ vortex

Fig. 1 is a cross-sectional view of the resin sheet 11 for encapsulation viewed from the front.

2(A) to 2(E) are diagrams showing the steps of manufacturing the encapsulating resin sheet 11 according to the first embodiment of the present invention.

Fig. 3 is a schematic view of the pressing device 30 in the step shown in Fig. 2(C).

Fig. 4 is a view showing the pressing speed at the time of pressing and the gas confirmed in the resin sheet 11 for packaging. A diagram of the relationship between the number of bubbles.

5(A) to (E) are photographs showing the surface of the encapsulating resin sheet 11 in the case where the pressing speed at the time of pressing the sheet is changed.

6(A) and 6(B) are views showing the vicinity of the outer periphery of the resin body 22 when the resin body 22 is stretched.

Fig. 7 is a view showing the relationship between the resin viscosity and the thickness unevenness of the resin sheet 11 for packaging.

Fig. 8 is a view showing the relationship between the temperature and the viscosity of the resin sheet 11 for encapsulation.

9(A) to 9(E) are diagrams showing the steps of manufacturing the encapsulating resin sheet 11 according to the second embodiment of the present invention.

10(A) to 10(C) are views showing a general example of manufacturing the electronic component module 200 using the resin sheet for packaging 205.

Fig. 11 is a view showing a method of manufacturing the encapsulating resin sheet 205 of the prior art.

[First Embodiment]

In an electronic component module in which a plurality of electronic components are mounted on a substrate, a resin sheet for encapsulation is used for insulating and encapsulating the electronic components. As shown in Fig. 1, the resin sheet for encapsulation 11 has a flat plate shape and has a thickness of 0.1 mm to 3.5 mm. The material of the resin sheet for encapsulation 11 is an insulating resin (for example, an epoxy resin), and for example, ceria or alumina is contained as a filler in the insulating resin in order to improve mechanical strength.

The protective film 12 is attached to the two main surfaces of the encapsulating resin sheet 11 in order to protect the surface of the encapsulating resin sheet 11. The material of the protective film 12 is, for example, PET (polyethylene terephthalate) or PTFE (polytetrafluoroethylene). In the case where the resin sheet 11 for encapsulation is used in the manufacturing process of the electronic component module, the release film 12 is peeled off from the surface of the protective film 12, and the protective film 12 is peeled off.

A method of manufacturing the encapsulating resin sheet 11 will be described with reference to Figs. 2(A) to 2(E) and Fig. 3 .

As shown in Fig. 2(A), a bottomed cylindrical mold 20 is prepared, and the liquid resin 21 is poured into the mold 20, and the resin body 22 is produced in a semi-hardened state by heat treatment.

The resin body 22 is an insulating resin containing a filler and is a material of the resin sheet 11 for encapsulation. The semi-hardened state refers to the state of the intermediate stage of the hardening reaction, which is also referred to as the B stage. In order to make the liquid resin 21 semi-hardened, in the case of an epoxy resin, heat treatment is performed in an oven at a temperature of 40 ° C to 160 ° C for 5 minutes to 120 minutes.

The resin body 22 can be used at a temperature of 60 ° C of 120 Pa. S~1800 Pa. s viscosity. The viscosity at this time is the AR550 manufactured by TA Instruments. The value measured under conditions of 8 mm, thickness 550 μm, frequency 1 Hz, strain 0.1%.

As shown in FIG. 2(B), the pressing plate 23 for molding the resin sheet 11 for packaging is formed, and the side plate 24 is disposed on the outer peripheral side of the main surface of the pressing plate 23. The side panels 24 may be shells or a plurality of panels may be formed in an annular manner. At the same time, the protective film 12 is placed in the region surrounded by the side plate 24 on the main surface of the pressing plate 23, and the resin body 22 produced in the step of FIG. 2(A) is placed on the center of the protective film 12.

The pressing plate 23 and the side plate 24 may be any material that can maintain a shape even when pressed, and for example, stainless steel or aluminum can be used. The side plate 24 is a member for determining the thickness of the formed resin sheet 11 for packaging, and is also set in consideration of the thickness of the protective film 12. When the thickness of the protective film 12 is 0.05 mm, the thickness of the side plate 24 may be in the range of 0.2 mm to 3.6 mm.

As shown in FIG. 2(C), another protective film 12 and the upper side are sequentially disposed above the resin body 22 so as to face the protective film 12 and the pressing plate 23 disposed in the step of FIG. 2(B). The plate 25 is pressed. Thereby, the resin body 22 is placed in a state in which the pair of pressing plates 23 and 25 are opposed to each other and the space 26 provided in the side plate 24 on the side.

Here, the pressing device used in the manufacturing steps of the encapsulating resin sheet 11 is performed. Description. Figure 3 is a schematic view of the pressing device 30 in the step shown in Figure 2(C). As shown in FIG. 3, the resin body 22 and the protective film 12 are disposed in the space 26 surrounded by the pair of pressing plates 23 and 25 and the side plates 24 provided on the side. In this state, the resin body 22 is heated and pressed by depressurizing the space 26 by the pressing device 30.

A pressure plate 32 is provided on the upper side of the pressing plate 25, and a pressure receiving plate 31 is provided on the lower side of the pressing plate 23. A heater 33 is built in each of the pressure plate 32 and the pressure receiving plate 31. The resin body 22 is heated by the heaters 33 via the pressing plates 23 and 25.

Further, a vacuum mechanism 38 is provided to surround the pressure plate 32 and the pressure receiving plate 31. The vacuum mechanism 38 is evacuated by a vacuum source (not shown). A through hole (not shown) is opened in the horizontal direction on the side plate 24, and the space 26 is also evacuated by the through hole to be in a reduced pressure state.

A drive shaft of the pressurizing servo mechanism 34 is connected to the upper side of the pressure plate 32. When the pressure plate 32 and the pressing plate 25 are pressed by lowering the drive shaft of the pressurizing servo mechanism 34, the resin body 22 is pressed. Further, the pressurizing servo mechanism 34 is disposed at the center of the top plate 36, and the top plate 36 is fixed to the pillar 37 of the base 35 standing below.

Here, a method of manufacturing the encapsulating resin sheet 11 will be described with reference to FIG. 2 again. Using the above-described pressing device 30, as shown in Fig. 2(D), the pair of pressing plates 23, 25 are moved in the direction in which they approach each other. Thereby, the resin body 22 located between the pressing plates 23 and 25 extends in the surface direction of the protective film 12, and the resin sheet 11 for encapsulation is formed.

The heating temperature at which the resin body 22 is extended is a temperature lower than the curing temperature of the resin body 22 (for example, 40 ° C to 160 ° C). The pressure formed by the pressure reduction in the space 26 surrounded by the pair of pressing plates 23, 25 and the side plates 24 is 5000 Pa or less. The pressing speed generated by the pressing plates 23 and 25 is 0.004 mm/sec or more and 0.06 mm/sec or less. The reason why the pressing speed is set within this range is described below.

The resin body 22 having a bottom area of 706.5 mm ² to 1962.5 mm ² and a height of 5 mm to 30 mm is formed into an area of 16900 mm ² and a thickness of 0.1 mm by the extension of the resin body 22 of the step shown in Fig. 2(D). A resin sheet 11 for packaging of 3.5 mm. The first embodiment is preferably applied to this range.

After the step shown in Fig. 2(D), the pressing force generated by the pressing plates 23, 25 is released, and the space 26 surrounded by the pressing plates 23, 25 and the side plates 24 is opened to the atmosphere. Thereby, the encapsulating resin sheet 11 with the protective film 12 on both sides as shown in FIG. 2(E) was produced.

In the step of Fig. 2(D), the resin body 22 is heated while being heated, and the heating temperature is lower than the curing temperature of the resin body 22, and the formed resin sheet 11 for packaging is also semi-hardened. Therefore, in the manufacturing process (see FIG. 10) of the electronic component module 200 using the encapsulating resin sheet 11, the electronic component can be embedded in the encapsulating resin sheet 11 and packaged.

Although the resin body 22 is somewhat extended in a state in which air bubbles are entrained, since the space 26 is evacuated at this time, the force radiated outward can be applied to the entrained air bubbles to effectively remove the air bubbles.

When the resin body 22 is extended, the pressing speed by the pressing plates 23 and 25 is 0.004 mm/sec or more and 0.06 mm/sec or less. This pressing speed is correctly set by the pressurizing servo mechanism 34. By setting the pressing speed within this range, the air bubbles remaining in the encapsulating resin sheet 11 can be reduced.

4 is a view showing the relationship between the relative pressing speed of the pressing plates 23 and 25 with respect to the resin body 22 and the number of bubbles confirmed in the encapsulating resin sheet 11. The resin sheet for encapsulation 11 is roughly produced by the above-described production method. The bubble is measured by subjecting the produced resin sheet 11 for packaging to a surface in a heated reduced pressure atmosphere (for example, a temperature of 100 ° C and a pressure of 200 Pa) to surface the bubbles. The number of bubbles is the number of bubbles having a diameter of 0.1 mm or more in the resin sheet 11 for encapsulation of 100 mm ² . The number of samples is n=10. As shown in FIG. 4, when the pressing speed is 0.09 mm/sec or more, the number of air bubbles is four or more on average, and when the pressing speed is 0.06 mm/sec or less, the bubble stability is reduced.

5(A) to 5(E) are photographs showing the surface of the encapsulating resin sheet 11 in the case where the pressing speed is changed. The area of each photo is 10000 mm ² . The photograph is a diagram in which the resin sheet 11 for encapsulation after production is placed in a heated decompression environment (for example, a temperature of 100 ° C and a pressure of 200 Pa) to surface the bubbles. When the pressing speed is 0.45 mm/sec and 0.225 mm/sec, a large number of bubbles are visible on the surface, and the number of bubbles is reduced at a pressing speed of 0.06 mm/sec, 0.009 mm/sec, 0.0004 mm/sec. .

According to these facts, when the pressing speed by the pressing plates 23 and 25 is set to be in the range of 0.004 mm/sec or more and 0.06 mm/sec or less, the number of bubbles remaining in the encapsulating resin sheet 11 can be reduced. Further, 0.004 mm/sec which is the lower limit of the pressing speed is set so that the pressing servo mechanism 34 can stably output the pressing speed of the pressing force.

The vicinity of the outer periphery of the resin body 22 when the resin body 22 is extended will be described with reference to Fig. 6 . Fig. 6(A) is a view showing a case where the pressing speed is 0.45 mm/sec, and Fig. 6(B) is a view showing a case where the pressing speed is 0.06 mm/sec.

As shown in FIGS. 6(A) and 6(B), when the resin body 22 extends in the direction of the arrow e, a vortex w is generated inside the resin body 22 located in the vicinity of the interface of the protective film 12. In FIG. 6(A), since the pressing speed is large, the vortex w is generated slightly inside the outer periphery of the resin body 22. Therefore, the gas in the vicinity of the outer periphery of the resin body 22 is entrained in the vortex w to become the bubble b, and the bubble b remains inside the resin body 22. On the other hand, in FIG. 6(B), since the pressing speed is small, the vortex w is generated on the outer periphery of the resin body 22. Therefore, the bubble b entrained in the vicinity of the outer periphery of the resin body 22 is guided to the outer peripheral end of the resin body 22 by the diffusion of the resin body 22 in the direction of the arrow e and the movement of the vortex w accompanying this. By the vacuuming of the vacuum mechanism 38 (see FIG. 3), the force of the bubble b guided to the outer peripheral end is discharged to the outside, and the residual of the bubble b inside the resin body 22 can be suppressed.

Further, a release treatment is performed on the surface of the protective film 12 used in the first embodiment. Since the effect of reducing the frictional force of the surface of the protective film 12 is performed by performing the mold release treatment, the slidability at the time of extending the resin body 22 is improved, and the entrained air bubbles b can be reduced. Further, the protective film 12 can be replaced every time the resin sheet 11 for packaging is manufactured, so that it is not necessary The sliding state at the time of extension of the resin body 22 can be favorably reproduced in consideration of the deterioration of the mold release treatment.

Further, according to the first embodiment, the pressing device 30 and the specific mold 20 can be prepared. Therefore, the resin sheet for packaging 11 can be produced without using expensive equipment. Moreover, when the pressing device 30 is used, the encapsulating resin sheet 11 having a relatively large film thickness can be produced by setting the side plate 24.

The encapsulating resin sheet 11 produced is preferably 120 Pa at a temperature of 60 ° C. S~1800 Pa. s viscosity. The viscosity at this time is the AR550 manufactured by TA Instruments. The value measured under conditions of 8 mm, thickness 550 μm, frequency 1 Hz, strain 0.1%. The thickness of the resin sheet for encapsulation 11 is a value measured by a reflection type laser displacement meter from the state in which the protective film 12 is attached to the two main surfaces of the encapsulating resin sheet 11. Fig. 7 is a view showing the relationship between the resin viscosity and the thickness unevenness of the resin sheet 11 for encapsulation, and the resin sheet 11 for encapsulation has a resin viscosity of 120 Pa. S~1800 Pa. In the case of s, the thickness of the resin sheet 11 for packaging is not more than 10 μm, whereas the resin viscosity is 100 Pa. When s, the thickness is not more than 15 μm, and the resin viscosity is 6000 Pa. The thickness unevenness in s is even more than 20 μm. Further, the thickness unevenness of the encapsulating resin sheet 11 is a value of 3σ, and the number of samples is n=20.

Moreover, FIG. 8 is a view showing an example of the relationship between the temperature and the viscosity of the resin sheet 11 for packaging. As shown in Fig. 8, if the temperature becomes higher, the viscosity tends to decrease, and the viscosity is 1800 Pa at a temperature of 60 °C. s, and the viscosity is 20 Pa at a temperature of 120 ° C. s. Reduce the viscosity of the resin to 20 Pa by increasing the temperature. s, the resin sheet for encapsulation 11 can be fluidized before being hardened to fill the resin material between the electronic component and the substrate.

[Second Embodiment]

A method of manufacturing the encapsulating resin sheet 11 of the second embodiment will be described with reference to FIG. 9(A) to FIG. 9(E). In the second embodiment, a method of manufacturing the resin sheet 11 for encapsulation directly between the pressing plates 23 and 25 without using the protective film 12 (see FIG. 2). In addition, the detailed description of the configuration and manufacturing conditions common to the first embodiment will be omitted. Also, during the pressing process Since the pressing device 30 is the same as that of the first embodiment, the description thereof is omitted.

As shown in Fig. 9(A), a bottomed cylindrical mold 20 is prepared, and the liquid resin 21 is poured into the mold 20, and the resin body 22 is produced in a semi-hardened state by heat treatment.

As shown in FIG. 9(B), the pressing plate 23 for molding the resin sheet 11 for packaging is formed, and the side plate 24 is disposed on the outer peripheral side of the main surface of the pressing plate 23. At the same time, the resin body 22 produced in the step of Fig. 9(A) is placed at the center of the main surface of the pressing plate 23 and surrounded by the side plate 24. The side plate 24 is a member for determining the thickness of the formed resin sheet 11 for packaging. However, in the second embodiment, since the protective film 12 is not used, it is not necessary to consider the thickness of the protective film 12. Moreover, a mold release treatment using a polyfluorene resin or the like is performed on the surface of the pressing plate 23 that is in contact with the resin body 22.

As shown in FIG. 9(C), the upper pressing plate 25 is disposed above the resin body 22 so as to face the pressing plate 23 disposed in FIG. 9(B). Thereby, the resin body 22 is placed in a state in which the pair of pressing plates 23 and 25 are opposed to each other and the space 26 provided in the side plate 24 on the side. Further, a release treatment using a polyoxymethylene resin or the like is also performed on the surface of the pressing plate 25 that is in contact with the resin body 22.

As shown in Fig. 9(D), by moving the pair of pressing plates 23, 25 in the direction in which they are close to each other, the resin body 22 located between the pressing plates 23, 25 is directed along the direction of the pressing plates 23, 25. The resin sheet 11 for encapsulation is formed by stretching. When the resin body 22 is extended, the resin body 22 is heated to a temperature lower than the hardening temperature. The space 26 surrounded by the pair of pressing plates 23 and 25 and the side plates 24 provided on the side is evacuated. The pressing speed of the pressing plates 23 and 25 is 0.004 mm/sec or more and 0.06 mm/sec or less.

After the step shown in Fig. 9(D), the pressing force generated by the pressing plates 23, 25 is released, and the space 26 surrounded by the pressing plates 23, 25 and the side plates 24 is opened to the atmosphere. Thereby, the resin sheet 11 for encapsulation shown in FIG. 9(E) was produced.

The surface of the pressing plates 23 and 25 used in the second embodiment is subjected to a mold release treatment. The effect of reducing the friction of the surfaces of the pressing plates 23, 25 by performing the demolding treatment As a result, the slidability of the resin body 22 when it is extended becomes good, and entrained air bubbles can be reduced.

According to the second embodiment, the resin sheet for encapsulation 11 can be produced without using the protective film 12. Therefore, the resin sheet for encapsulation 11 can be manufactured more inexpensively.

11‧‧‧Packaging resin sheet

12‧‧‧Protective film

20‧‧‧Mold

21‧‧‧Liquid resin

22‧‧‧ resin body

23, 25‧‧‧ Press plate

24‧‧‧ side panels

26‧‧‧ Space

Claims (3)

A method for producing a resin sheet for encapsulation, which is a method for producing a resin sheet for encapsulation for insulating and encapsulating a plurality of electronic components mounted on a substrate, and comprising the steps of: a resin body arranging step The resin body in a semi-hardened state in which the material of the resin sheet for encapsulation is disposed is disposed in a space surrounded by the pair of pressing plates and the side plates provided on the outer peripheral side of the pressing plate; and an extending step And drawing the vacuum into the enclosed space, and heating the resin body at a temperature lower than a curing temperature of the resin body, and pressing the pressing plate at a pressing speed of 0.004 mm/sec or more and 0.06 mm/sec or less The resin body is pressed and extended. The method for producing a resin sheet for encapsulation according to claim 1, wherein in the resin body disposing step, a protective film subjected to a release treatment is inserted between the resin body and the pressing plate, and in the extending step, The resin body is pressed to extend in the surface direction of the protective film. The method for producing a resin sheet for encapsulation according to claim 1, wherein the pressing plate is subjected to a mold release treatment, and in the extending step, the resin body is pressed to extend in a surface direction of the pressing plate.