JP2005135948A - Chip-type electronic component and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coating method for thinning a film of outer covering resin and for miniaturizing a product without using solvent in the formation of coating of a chip-type electronic component by resin. <P>SOLUTION: Non-solvent-type B stage resin in a sheet or a plurality of specified shapes is bonded to a chip-type electronic component element. Then, it is gelated or hardened to form the cutter covering. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a chip-type electronic component and a manufacturing method thereof, and more particularly to a chip inductor covered with a resin as an exterior material and a manufacturing method thereof.

Currently, in order to realize high-density surface mounting on a circuit board using a chip-type electronic component automatic mounting machine, electronic components such as inductors and capacitors are being miniaturized.
For further miniaturization of electronic components, not only miniaturization of elements of electronic components but also miniaturization (thinning) of exterior of electronic components and good exterior formability are required.

  A chip-type inductor formed by winding a wire composed of a conductive wire and an insulating layer covering the core portion of a drum core as a conventional resin sheathing method for downsizing a chip-type electronic component such as a chip inductor Prepare the element, rotate the drum disk coated with liquid resin on the surface while contacting the winding wire of the element, apply the liquid resin around the winding wire with the drum disk, The liquid resin applied to the element is touch-dried, and the element coated with the touch-dried resin is placed in the storage part of the mold plate equipped with a heat-resistant rubber elastic body, and the coating resin is thermally cured. However, there is a method of molding the exterior resin with the mold plate (for example, see Patent Document 1).

JP 2000-286140 A

  However, in general, a chip inductor uses a resin highly filled with ferrite powder as an exterior resin in order to achieve a high inductance and a high shield. Therefore, the conventional resin coating method has the following problems.

  In the conventional resin sheathing method, when the sheathing resin is made of a solventless resin, since the ferrite powder is highly filled (75% by weight or more) in the sheathing resin, the resin viscosity becomes high, that is, the resin There is a problem that production efficiency is inferior, such as poor fluidity and poor workability such as application of resin to an element by a drum disk.

When the exterior resin is made of a solvent-type resin, the solvent volatilizes during touch-drying, which may cause voids inside the exterior resin, which may deteriorate the strength of the exterior resin. There is a problem that it may cause variation.
Also, in the plating process for forming the conductive terminal after molding the exterior resin, the plating solution penetrates into the void inside the exterior resin and further reaches the winding wire part, affecting the wire coating and causing a short circuit. There's a problem.

Further, when the exterior resin is made of a solvent-type resin, a harmful solvent is volatilized in the outside air, which causes a problem for human health and an environmental problem.
Further, since the resin application by the drum disk used in the above conventional resin sheathing method uses a liquid resin, as the element shape, particularly the core becomes smaller and lower in profile, the end of the core (conductive terminal) There is a problem that stains due to the resin in the forming portion) are likely to occur, and it becomes difficult to stabilize the application of the resin. For this reason, if it is attempted to prevent contamination by the resin or stabilize the application of the resin, there arises a problem that the working efficiency is deteriorated.

  Accordingly, an object of the present invention is to provide a chip-type component by a new resin coating method and a method for manufacturing the same, which solve the problems of the conventional resin coating method.

  In order to achieve the above object, the present invention provides a chip-type electronic component coated with an exterior resin, wherein the exterior resin adheres the solvent-free B-stage resin to the chip-type electronic component element. Provided is a chip-type electronic component characterized by being formed by gelling and curing.

  Further, the present invention provides a method for manufacturing a chip-type electronic component comprising a step of coating a chip-type electronic component element with an exterior resin and a step of curing the resin. Provided is a method for manufacturing a chip-type electronic component comprising attaching a mold B-stage resin and gelling the B-stage resin.

  In the present invention, since a solvent-free B-stage resin is used as the exterior resin, no harmful solvent is volatilized from the resin to the outside air when the resin is dried or cured, thus causing both human health problems and environmental problems. Chips with stable and uniform characteristics that can prevent the penetration of the plating solution into the exterior resin in the plating process, which is a subsequent process, without generating voids inside the exterior resin due to the volatilization of the solvent. Mold electronic components can be provided.

  In the present invention, since the solvent-free B-stage resin is made into a sheet shape or a chip having a specific shape is attached to the element and gelled and cured, the element is covered with the exterior resin, so that the liquid resin Compared to the conventional resin sheathing method by coating, the chip type electronic component manufacturing method is excellent in thinning of the resin and thinning of the exterior resin of the chip type electronic component, further downsizing and excellent production efficiency Can be provided.

  In the present invention, when the B-stage resin is gelled, the melt viscosity of the B-stage resin and the time until gelation are adjusted, so that good exterior molding can be performed, and a small and low-profile chip-type electronic Parts can be provided.

  In the present invention, it is possible to provide a chip inductor having excellent characteristics by including ferrite powder in the exterior resin and setting the magnetic permeability of the exterior resin to 4 to 8 by 8 MHz measurement value.

  The chip-type electronic component of the present invention is a chip-type electronic component that is coated with an exterior resin. The exterior resin gels the B-stage resin after the solvent-free B-stage resin is attached to the chip-type electronic component element. It is formed by hardening. The method of the present invention for manufacturing such a chip-type electronic component has a step of coating an exterior resin on the chip-type electronic component element and a step of curing the resin, and the step of coating the resin includes: A solvent-free B-stage resin is attached to the element, and the B-stage resin is gelled.

  As a raw material for the solventless B-stage resin used in the present invention, a thermosetting epoxy resin, a phenol resin, and an epoxy phenol resin can be used, and an epoxy resin is particularly preferable. This B-stage resin is formed by adding a curing agent to a raw material resin and heat-treating it. For example, it can be formed by adding a dicyandiamide curing agent to an epoxy resin and performing a heat treatment at 150 to 170 ° C. for 5 to 20 minutes.

The B stage resin used in the present invention can be used as a chip having a sheet shape or a specific shape.
When a sheet-shaped B-stage resin is used, one or more of the sheet-shaped B-stage resins can be coated on the element.
For example, when producing a B-stage resin sheet, as shown in FIGS. 1a and 1b, a raw material resin with a curing agent added to a thickness of 100 to 300 μm is printed on the support film 2 with a metal mask, Thereafter, the B stage resin sheet 1 is produced by heat treatment. Although the support film to be used is not particularly limited, it is preferable to use a polyethylene terephthalate (PET) film whose surface is subjected to silicone release treatment.

When a B-stage resin chip having a specific shape is used, a shape that covers the element can be formed by combining a plurality of the chips. Preferably, a shape that covers the element is formed by combining two chips having the specific shape.
For example, the specific-shaped chip has a U-shape or L-shape as shown in FIGS. 1c to 1f, and when a U-shaped B-stage resin is produced, FIGS. 1g and 1h are used. It can be produced using a silicone die as shown in FIG.

  The cured exterior resin preferably has a glass transition temperature of 20 to 80 ° C. The exterior resin can contain magnetic powder. When manufacturing a chip inductor as a chip-type electronic component, it is preferable that the exterior resin contains ferrite powder, and the ferrite powder-containing exterior resin has a magnetic permeability of 4 to 8 at an 8 MHz measurement value.

Next, the B-stage resin is coated on the element. This is because the B-stage resin is adhered to the portion of the element to be resin-coated (for example, in the case of a chip inductor, the winding wire of the element). For example, it can be carried out by gelling the B-stage resin by heating with a pressing die.
In this case, the B-stage resin is preferably gelled at 170 ° C. with a melt viscosity of 40 to 100 Pa · s, and the gel time of the B-stage resin is preferably 20 to 60 seconds. Note that the gel time of the B-stage resin is the time during which the pressing die is pressed when the gel is formed using a pressing die, for example.

  When the above-mentioned sheet shape or U-shaped B-stage resin is gelled, a U-shaped stamping die as shown in FIGS. 3a and 3b can be used, and the above-mentioned L-shaped B-stage resin can be used. Can be gelled, an L-shaped pressing die as shown in FIG. 3c can be used. For example, two sheet-shaped B-stage resins are embossed and gelled by a stamping die, so that the resin portion that is not attached to the device before the stamping is attached to the device and the device is coated with the resin. The power portion is completely covered with the resin (see FIG. 4). Further, even when a plurality of B-stage resin chips having a specific shape are combined to cover the element, the portion to be resin-coated of the element is completely covered with the resin by embossing and gelling.

After the resin is gelled, the main curing is preferably performed by heat treatment at 150 to 170 ° C. for 30 to 60 minutes to increase the degree of curing of the resin, and the exterior molding is completed.
The cured product of the resin preferably has a glass transition temperature (Tg) of 20 to 80 ° C., particularly preferably 50 to 60 ° C. On the other hand, when Tg is higher than 80 ° C., core cracks after reflow occur, and when Tg is lower than 20 ° C., the cured resin surface is soft and has low heat resistance.

In the case of a chip inductor, for example, in the case of a chip inductor, a conductive terminal is provided at the wire ends taken out at both ends of the drum core to complete the chip electronic component.
Hereinafter, the present invention will be described in more detail with reference to an embodiment in which a chip inductor is manufactured as a chip-type electronic component.

  In this example, Table 1 shows the raw materials for the B-stage resin so that the glass transition temperatures (Tg) of the exterior resin (cured product) of the chip inductor are 0, 20, 50, 80, and 100 ° C., respectively. Ferrite powder (permeability of the ferrite material itself) is added to the resin component in which bisphenol A or F type epoxy resin, linear flexible epoxy resin, reactive diluent, curing agent (dicyandiamide) and coupling agent are blended at different blending ratios. A resin composition containing 75% by weight of a powder having a magnetic permeability of 700 to 800 and having an average particle diameter of 1.8 μm and 25 to 35 μm in a ratio of 3: 7 was used.

  The above resin composition was printed to a thickness of 100 to 300 μm with a metal mask on a PET film having a surface subjected to silicone release treatment. Then, the printed resin sheet was heat-treated at 150 to 170 ° C. for 5 to 20 minutes to produce a B stage resin sheet (see FIGS. 1a and 1b).

  As the chip inductor element, an element was prepared by winding a wire 9 composed of a conductive wire and an insulating layer covering the core portion 8 of the drum core 7 as shown in FIGS. . In FIGS. 2 a and 2 b, reference numeral 12 indicates the end of the winding wire drawn on the surface of the end of the drum core 7 in order to form conductive terminals at both ends of the drum core 7. Then, the two produced B-stage resin sheets were heated at 80 to 120 ° C. and adhered to the winding wires of the prepared elements (see FIGS. 2a to 2c).

  Next, as shown in FIG. 3a, the element to which the B-stage resin sheet is attached is pressed while heating at 170 ° C. using two pressing molds 10 whose surfaces are subjected to mold release treatment, 1 gelled. At this time, the melt viscosity of the resin was 70 Pa · s and the gelation time was 15 seconds. FIG. 4 shows a state of the chip inductor formed by the B-stage resin sheet being gelled and packaged.

  Next, the chip inductor element covered with the gelled resin was heat-treated at 150 to 170 ° C. for 30 to 60 minutes to fully cure the resin. As a result, the degree of cure of the exterior resin was increased, and the exterior molding of the chip inductor element was completed. Chip inductors coated with an exterior resin (cured product) having glass transition temperatures (Tg) of 0, 20, 50, 80, and 100 ° C. were produced. The outer dimensions of the completed chip inductor were 2.5 mm × 1.8 mm × 1.8 mm.

  Finally, conductive terminals were provided at the ends of the wires taken out at both ends of the core not covered with the exterior resin, and Ni and Sn plating were performed to complete the chip inductor.

  With respect to the chip inductor manufactured according to the above and coated with an exterior resin having a different Tg, the occurrence of core cracks after reflow was tested. The results are shown in Table 2.

  From Table 1, cracks occurred in the exterior resin having a Tg of 100 ° C. On the other hand, an exterior resin having a Tg of 0 ° C. is not preferable because the resin surface is soft and there is a concern that heat resistance is weak. Thereby, a desirable Tg range is 20-80 degreeC.

  This example is similar to Example 1 except that the melt viscosity of the B-stage resin sheet when gelled at 170 ° C. was changed to 10, 20, 30, 40, 70, 100, and 120 Pa · s. A chip inductor coated with an exterior resin having a temperature of 50 ° C. was produced. The appearance after chip molding of the chip inductor and burrs due to resin flow were evaluated. The results are shown in Table 3.

  From Table 2, when the resin had a melt viscosity of 10 to 30 Pa · s, the resin flowed out to the terminal portion because the melt viscosity was low, and burrs were generated. On the other hand, when the melt viscosity of the resin exceeds 100 Pa · s, the fluidity is poor and the appearance is not expected. Therefore, the optimum melt viscosity of the resin during gelation is in the range of 40 to 100 Pa · s.

  In this example, except that the gelation time of the B-stage resin sheet was changed to 10, 20, 40, 60, 80 and 100 seconds, it was coated with an exterior resin having a Tg of 50 ° C. as in Example 1. A chip inductor was fabricated. The appearance after chip molding of the chip inductor and burrs due to resin flow were evaluated. The results are shown in Table 4.

  From the results of Table 3, when the gelation time was as short as 10 seconds, the appearance of the resin was poor due to insufficient resin flow. When the gelation time was as long as 80 seconds or longer, the resin flowed out to the conductive terminal portion, and burrs were generated. Therefore, the gel time of the resin is desirably about 20 to 60 seconds.

  In this example, the amount of ferrite powder contained in the resin was changed to 60 to 85% by weight, and the magnetic permeability of the exterior resin was changed to 3, 3.5, 4, 5, 6, 7, 8, and 9. As in Example 1, a chip inductor coated with an exterior resin having a Tg of 50 ° C. was produced. About the produced chip inductor, the self-inductance value (L value) of a coil and the product characteristic of direct current superposition were evaluated. The results are shown in Table 5.

  From the results of Table 4, when the permeability of the exterior resin is lower than 4, the increase rate of the L value is low, and in order to obtain a predetermined L value, it is necessary to increase the number of turns of the winding. Increasing the number is not preferable because the direct current resistance characteristic (RDC characteristic) deteriorates. On the other hand, when the magnetic permeability of the exterior resin is higher than 8, the L-value up rate is a satisfactory value, so the number of turns of the winding can be reduced. Absent. Therefore, the permeability of the exterior resin is desirably 4-8.

It is a schematic side view which shows an example of the B stage resin sheet supported by the support film. It is a schematic plan view which shows an example of the B stage resin sheet supported by the support film. It is a schematic side view which shows an example of the B-stage resin chip of a specific shape. It is a schematic plan view which shows an example of the B-stage resin chip of a specific shape. It is a schematic side view which shows another example of the B-stage resin chip of a specific shape. It is a schematic plan view which shows another example of the B stage resin chip of a specific shape. It is sectional drawing which shows an example of the cutting die for producing the B-stage resin chip of the specific shape shown by FIG. 1c and FIG. 1d. It is a top view which shows an example of the cutting die for producing the B stage resin chip of the specific shape shown by FIG. 1c and FIG. 1d. It is a schematic side view of an example of the state which adhered the B stage resin sheet to the single side | surface of the chip inductor element. It is a schematic side view of an example of the state which made the B stage resin sheet adhere to both surfaces of a chip inductor element. It is a schematic plan view of an example of the state which made the B stage resin sheet adhere to the single side | surface of a chip inductor. It is a schematic side view which shows an example of the state just before gelatinizing a B stage resin sheet with a pressing die. FIG. 2 is a schematic side view showing an example of a state immediately before the B-stage resin chip having a specific shape shown in FIGS. 1c and 1d attached to the chip inductor element is gelled by a pressing die. It is a schematic side view which shows an example of the state which gelatinizes with a pressing die the B-stage resin chip of the specific shape shown by FIG. 1e and FIG. 1f which adhered to the chip inductor element. It is a schematic side view which shows the state of the chip inductor element coat | covered with resin after gelatinization.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 B stage resin sheet 2 Support film 3 B shape resin chip of specific shape 4 B stage resin chip of specific shape 5 Cutting die 6 Opening part 7 Drum core 8 Core part 9 Winding wire 10 Stamping die 11 After gelatinization Exterior resin 12 Wire end

Claims (23)

In chip-type electronic parts covered with exterior resin,
A chip-type electronic component, wherein the exterior resin is formed by attaching a solvent-free B-stage resin to a chip-type electronic component element and then gelling and curing the B-stage resin.   The chip-type electronic component according to claim 1, wherein the B-stage resin is a resin selected from the group consisting of a thermosetting epoxy resin, a phenol resin, and an epoxy phenol resin.   The chip-type electronic component according to claim 1, wherein the B-stage resin is an epoxy resin.   2. The chip-type electronic component according to claim 1, wherein the B-stage resin is formed by adding a dicyandiamide curing agent to an epoxy resin and performing a heat treatment at 150 to 170 ° C. for 5 to 20 minutes.   The chip-type electronic component according to claim 1, wherein the cured resin has a glass transition temperature of 20 to 80 ° C.   The chip-type electronic component according to claim 1, wherein the exterior resin contains magnetic powder.   The chip-type electronic component according to claim 6, wherein the magnetic powder is a ferrite powder, and the ferrite powder-containing exterior resin has a magnetic permeability of 4 to 8 as measured at 8 MHz.   The chip type electronic component according to claim 1, wherein the chip type electronic component is a chip inductor.   In a manufacturing method of a chip-type electronic component having a step of coating a chip-type electronic component element with an exterior resin and a step of curing the resin, the step of coating the resin attaches a solvent-free B-stage resin to the device And manufacturing the chip-type electronic component, wherein the B-stage resin is gelled.   The manufacturing method according to claim 9, wherein the B-stage resin is a resin selected from the group consisting of a thermosetting epoxy resin, a phenol resin, and an epoxy phenol resin.   The manufacturing method according to claim 9, wherein the B-stage resin is an epoxy resin.   The manufacturing method according to claim 9, wherein the B-stage resin is formed by adding a dicyandiamide curing agent to an epoxy resin and performing a heat treatment at 150 to 170 ° C. for 5 to 20 minutes.   The manufacturing method according to claim 9, wherein the B-stage resin has a sheet shape.   The manufacturing method according to claim 13, wherein the element is covered with one or more of the sheet-shaped B-stage resins.   The manufacturing method according to claim 9, wherein the B-stage resin is a plurality of chips having a specific shape, and the shape covering the element is formed by combining the plurality of chips.   The manufacturing method according to claim 15, wherein a shape covering the element is formed by combining two chips having the specific shape.   The production method according to any one of claims 9 to 16, wherein the gelation of the B-stage resin is performed by heating with a pressing die.   The manufacturing method according to any one of claims 9 to 17, wherein the B-stage resin is gelled at 170 ° C with a melt viscosity of 40 to 100 Pa · s.   The manufacturing method according to claim 18, wherein the gel time of the B-stage resin is 20 to 60 seconds.   The manufacturing method of Claim 9 whose glass transition temperature of exterior resin after hardening is 20-80 degreeC.   The manufacturing method according to claim 9, wherein the exterior resin contains magnetic powder.   The manufacturing method according to claim 21, wherein the magnetic powder is ferrite, and the ferrite powder-containing exterior resin has a permeability of 4 to 8 at an 8 MHz measurement. The manufacturing method according to claim 9, wherein the chip-type electronic component is a chip inductor.

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