JP2007067042A - Manufacturing method of substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inexpensively provide an LED substrate whose heat dissipation and irradiation efficiency can be enhanced. <P>SOLUTION: In a manufacturing method of the substrate for bonding a circuit pattern 3 which has a surface of high reflection factor, and is formed of a conductive metal plate to a surface of an insulator 2 made of a resin structure having a recess 2a; low cost is realized by high heat dissipation and the circuit pattern as a reflection plate. Desired characteristics can be obtained freely, by selecting a material of resin structure and changing the area and the thickness of the circuit pattern, according to the requirement of heat dissipation and luminescence, or selecting the type of plating on the surface and changing the reflection factor. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to, for example, a method for manufacturing a substrate that is used in an LED light-emitting device, mounts the LED, radiates heat generated from the LED, and increases the irradiation efficiency of light generated from the LED.

  In recent years, in accordance with demands for higher performance and smaller size of electronic devices, higher density and higher functionality of electronic components have been screamed. Therefore, due to downsizing, higher functionality, and high-density mounting of electronic components, the temperature rise of electronic components has become a major problem, and a method for increasing heat dissipation of electronic components has become an important issue.

  Among electronic components, LEDs have a characteristic that the amount of light emission decreases when the temperature rises too much, and heat dissipation is indispensable for increasing the amount of light emission.

  As a technique for increasing the heat dissipation of the LED, a method of attaching the LED to a metal substrate and diffusing heat from the back surface of the LED is known.

  FIG. 12 is a cross-sectional view of an LED mounted on a conventional metal substrate 30. In FIG. 12, in the conventional configuration, the LED 5 a is mounted on the wiring pattern 32 on the metal substrate 30. There is an insulating layer 33 between the metal plate 31 and the wiring pattern 32. The LED 5 a can radiate heat to the metal plate 31 through the wiring pattern 32 and the insulating layer 33.

  A resin block 34 having a conical hole is laminated on the metal substrate 30, and a bright plating 35 is applied to the inside of the conical hole. This serves as a reflector for reflecting the light emitted from the side surface of the LED 5a to the upper surface.

As prior art document information relating to this application, for example, Patent Document 1 is known.
JP-A-2005-159045

  In the above conventional configuration, the wiring pattern 32 is a copper foil having a thickness of about 50 μm, and the insulating layer 33 is a resin film and has a problem in that sufficient heat radiation cannot be performed because of low thermal conductivity. In addition, since the light emission of the LED 5a is performed not only in the vertical direction but also in the parallel direction to the substrate, a partially plated block having the function of a reflector must be installed on the substrate in order to make use of the light irradiated in the parallel direction. It was necessary to increase the cost.

  This invention solves the said problem, and aims at providing the board | substrate for LED which raises radiation efficiency at low cost while improving heat dissipation.

  In order to achieve the above object, the present invention is characterized by a method for manufacturing a resin structure having a conical recess and a circuit board made of a conductive metal plate having a highly reflective surface on the surface thereof. To do.

  According to the above manufacturing method, the light irradiated from the side surface of the LED mounted on the bottom of the concave portion becomes the reflector and is reflected in the direction perpendicular to the substrate, so that the irradiation efficiency can be increased. Moreover, since the circuit pattern which consists of an electroconductive metal plate which comprises this reflector can be thickened, thermal conductivity is large, and it can improve heat dissipation. Select the resin structure material with recesses, change the area or thickness of the circuit pattern made of conductive metal plate, or select the type of surface plating according to the degree of heat dissipation and light emission Thus, desired characteristics can be freely obtained by changing the reflectance.

  Hereinafter, the invention described in all claims of the present invention will be described using embodiments with reference to the drawings.

(Embodiment 1)
FIG. 1 is a cross-sectional view of a state in which an LED is mounted on an LED substrate of the present invention, and FIG. 2 is a perspective view thereof.

  In FIG. 1, an insulator 2 made of a heat conductive resin containing an inorganic filler is joined to an aluminum base 1 with a mortar-like (conical shape) recess 2a. A circuit pattern 3 made of a copper plate having a thickness of 0.5 mm is attached to the surface. The surface of the circuit pattern 3 is tin-plated with a nickel base. The LED 5 is bonded to the bottom of the recess 2a of the substrate through bumps 6 in a face-down state. The arrows in FIG. 1 indicate the path of light emitted from the LED 5. The insulator 2 is made of an insulating resin containing an inorganic filler, and the thermal conductivity of the inorganic filler is larger than that of the insulating resin.

The inorganic filler contains at least one selected from Al ₂ O ₃ , MgO, SiO ₂ , BN, and AlN. When an inorganic filler is used, heat dissipation is excellent. In particular, the use of MgO can increase the linear expansion coefficient, the use of SiO ₂ can reduce the dielectric constant, and the use of BN can reduce the linear expansion coefficient.

The inorganic filler has a substantially spherical shape and a diameter of 0.1 to 100 μm. The smaller the particle size, the better the filling rate into the insulating resin. The filling amount of the inorganic filler in the insulator 2 is filled at a high concentration of 70 to 95% by weight in order to increase the thermal conductivity. In particular, in the present embodiment, the inorganic filler is a mixture of two types of Al ₂ O ₃ having an average particle diameter of 3 μm and an average particle diameter of 12 μm. By using the Al ₂ O ₃ of the large and small two types of particle size, it is possible to fill the Al ₂ O ₃ of small particle size in the gap Al ₂ O ₃ of large particle size, Al ₂ O ₃ 90 wt% near Can be filled to a high concentration. In this case, the thermal conductivity of the insulator 2 is about 5 W / mK.

  The thermosetting insulating resin contains at least one resin among epoxy resin, phenol resin, and cyanate resin. These resins are excellent in heat resistance and electrical insulation.

  If the thickness of the insulator 2 is reduced, the heat generated in the LED 5 mounted on the circuit pattern 3 can be easily transferred to the base 1, but conversely, the withstand voltage becomes a problem, and if it is too thick, the thermal resistance increases. The optimum thickness may be set in consideration of the withstand voltage and thermal resistance.

The metal base 1 is made of aluminum, copper, or an alloy containing them as a main component, which has good thermal conductivity. In particular, in the present embodiment, the thickness of the base 1 is 1 mm. In addition, the base 1 is not only a plate-like one, but in order to increase heat dissipation, a fin portion is formed on the surface opposite to the surface on which the insulator 2 is laminated in order to increase the surface area. Also good. The total expansion coefficient is 8 × 10 ⁻⁶ / ° C. to 20 × 10 ⁻⁶ / ° C. By bringing the expansion coefficient close to the linear expansion coefficient of the base 1 or the LED 5, warpage and distortion of the entire substrate can be reduced.

(Embodiment 2)
FIG. 3 is a sectional view showing another embodiment of the present invention, and FIG. 4 is a perspective view thereof.

  In FIG. 3, an insulator 2 made of a heat conductive resin containing an inorganic filler is joined on an aluminum base 1 with a mortar-shaped recess 2a, A circuit pattern 3 made of a copper plate having a thickness of 0.5 mm is attached. The surface of the circuit pattern 3 is tin-plated with a nickel base. LED5 is installed in the bottom of the dent 2a part of this board | substrate. The arrows in FIG. 3 indicate the path of light emitted from the LED 5. The electrical wiring between the LED 5 and the circuit pattern 3 is formed by a wire bonding method using a wire 7.

(Embodiment 3)
FIG. 5 is a sectional view showing another embodiment of the present invention.

  In FIG. 5, an insulator 2 made of a heat conductive resin containing an inorganic filler is joined on an aluminum base 1 with a mortar-shaped recess 2 a, A circuit pattern 3 made of a copper plate having a thickness of 0.5 mm is embedded. The surface of the circuit pattern 3 is tin-plated with a nickel base. LED5 is installed in the bottom of the dent 2a part of this board | substrate. The arrows in FIG. 5 indicate the path of light emitted from the LED 5. The electrical wiring between the LED 5 and the circuit pattern 3 is formed by a wire bonding method using a wire 7.

(Embodiment 4)
FIG. 6 is a cross-sectional view showing another embodiment of the present invention.

  In FIG. 6, an insulator 2 made of a heat conductive resin containing an inorganic filler is joined on an aluminum base 1 with a mortar-shaped recess 2 a, A circuit pattern 4 is formed by electroless plating. Although not shown in FIG. 6, as in FIG. 5, the LED 5 is installed at the bottom of the recess 2 a portion of the substrate, and the electrical wiring between the LED 5 and the circuit pattern 4 is connected by a wire bonding method using the wire 7. The

  The manufacturing process of such an LED substrate is as follows.

  FIG. 7 is a diagram showing a manufacturing process of the LED substrate of the present invention.

  In FIG. 7 (a), the circuit pattern 3 made of a copper plate having a thickness of 0.5 mm and subjected to nickel plating on the surface is formed so as to have a conical recess 3a. While being fixed to a lower mold having a convex portion 11 a that fits into a conical concave portion 3 a, an aluminum base 1 on which an insulator 2 is laminated is guided by an upper mold 12 with a push plate 13. Push in and pressurize and heat in the mold as shown in FIG. 7B to cure the uncured insulator 2 so that the circuit pattern 3 is embedded in the insulator 2 to form an integrated LED substrate. Is done. At this time, it takes 10 minutes or more at 120 ° C. to cure the uncured thermosetting insulating resin contained in the insulator 2 to a hardness sufficient to be taken out from the upper and lower molds 11 and 12. Therefore, in order to shorten this time and increase productivity, a pregel agent is mixed. The pregel material is a thermoplastic resin powder, and functions to act by absorbing the liquid component of the uncured thermosetting insulating resin and expanding the uncured insulating resin into a gel. Since the pregel agent acts at a temperature of 120 ° C. for about 1 minute and can be made sufficiently hard to be taken out from the mold, productivity can be increased.

  FIG. 8 is a diagram showing another manufacturing process of the LED substrate of the present invention.

  As shown in FIG. 8, a circuit pattern 3 made of a copper plate having a thickness of 0.5 mm and having a nickel base tin-plated on the surface is shaped to have a conical recess 3a. The circuit pattern 3 is affixed on the insulator 2 by laminating it on the insulator 2 that has already been cured and has a recess 2a that fits into the shape of the recess 3a, via an adhesive (not shown). Is.

  FIG. 9 is a diagram showing another manufacturing process of the LED substrate of the present invention.

  As shown in FIG. 9, the circuit pattern 3 made of a copper plate with a thickness of 0.5 mm on which the nickel base is tin-plated is formed so as to have a conical recess 3 a, The circuit pattern 3 is formed on the insulator 2 by heating after laminating on the insulator 2 having a concavity 3a and a recess 2a that fits into the conical recess 3a but not yet polymerized and pre-gelled. It will be pasted on top.

  FIG. 10 is a diagram showing another manufacturing process of the LED substrate of the present invention.

  As shown in FIG. 10, a circuit pattern 3 made of a copper plate having a thickness of 0.5 mm and subjected to tin plating with a nickel base is formed on the surface so as to have a conical recess 3a. The circuit pattern 3 is formed as shown in FIG. 11 by heating after laminating on the insulator 2 that has a recess 2a that fits into the shape of the recess 3a and has not yet undergone a polymerization reaction and is pre-gelled and semi-cured. It is embedded on the insulator 2.

  As described above, the LED substrate of the present invention has a heat radiation function and a light collecting function by reflecting light, and the circuit pattern and the reflecting plate are integrated so that the performance of the LED can be sufficiently obtained at low cost. Can be provided.

Sectional drawing which mounted LED in the board | substrate in one embodiment of this invention The perspective view which mounted | wore with LED in the board | substrate in one embodiment of this invention Sectional drawing which mounted LED in the board | substrate in other embodiment of this invention. The perspective view which mounted LED in the board | substrate in other embodiment of this invention. Sectional drawing which mounted LED in the board | substrate in other embodiment of this invention. Sectional drawing which mounted LED in the board | substrate in other embodiment of this invention. (A) (b) is sectional drawing which shows the manufacturing process of the board | substrate of one Embodiment of this invention. Sectional drawing which shows the other manufacturing process of the board | substrate of this invention Sectional drawing which shows the other manufacturing process of the board | substrate of this invention Sectional drawing which shows the other manufacturing process of the board | substrate of this invention Sectional drawing which shows the manufacturing process of the board | substrate of FIG. Sectional view of LED mounted on a conventional metal substrate

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base 2 Insulator 3 Circuit pattern 4 Circuit pattern by plating 5 LED element 6 Bump 7 Wire 11 Lower mold 12 Upper mold 13 Push plate

Claims (6)

A circuit pattern made of a conductive metal plate is molded in advance so as to have a recess, and a resin is laminated in a state of being fixed to a mold having a protrusion that fits into the recess, and pressurization and heating are performed in the mold. And the uncured resin is cured. The method for manufacturing a substrate according to claim 1, wherein the resin contains a pregel material and is taken out of the mold in a semi-cured state. A method for producing a substrate, comprising: molding a resin into a resin structure having a concave portion and curing the resin pattern; and attaching a circuit pattern made of a conductive metal plate to the surface of the resin structure using a heat conductive adhesive. A resin structure containing a pregel material is placed in a semi-cured state in which a polymerization reaction hardly proceeds at the time of molding on a resin structure having a recess, and a circuit pattern made of a conductive metal plate is attached to the surface and heated. A method for manufacturing a substrate, characterized in that the substrate is cured. A method for producing a substrate, characterized in that a resin structure having a concave portion is made to be semi-cured at the time of molding, a circuit pattern made of a conductive metal plate is embedded in the surface, and then heated and cured. The method for manufacturing a substrate according to claim 1, wherein the method is performed in a vacuum atmosphere at a pressure of 50000 Pa or less.

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