JP2009302196A - Insulated metal base circuit board and hybrid integrated circuit module using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an insulated metal base circuit board for reducing a warpage behavior generated by a thermal load in the packaging process of a substrate, and to provide a hybrid integrated circuit module using the circuit board. <P>SOLUTION: The insulated metal base circuit board is provided with a conductor metal on metal foil via an insulating layer wherein the area of the conductor metal is not smaller than 50% of the entire area of the circuit surface of the insulated metal base circuit board, and the ratio of the circuit portion in the conductor metal is not smaller than 5% and not larger than 50% at least in one section passing through the center of gravity at the side of the circuit surface of the insulated metal base circuit board. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an insulating metal base circuit board and a hybrid integrated circuit module using the same.

  2. Description of the Related Art Conventionally, various circuit boards have been used in order to realize surface mounting that enables miniaturization and labor saving at the time of mounting, and semiconductor elements and light emitting diodes (LEDs: Light Emitting Diodes) are used on these circuit boards. Hybrid integrated circuit modules on which various surface mount electronic components such as elements, chip resistors and chip capacitors are mounted are used. In particular, an insulating metal base circuit board in which an insulating layer made of an epoxy resin or the like filled with an inorganic filler is provided on a metal plate and a circuit is provided on the insulating layer is used as a circuit board for mounting a highly exothermic electronic component. It has been.

  In addition, various electronic devices are required to be lighter and thinner. For example, liquid crystal display devices have been made to make the screen thinner and thinner. Therefore, it is conceivable to use an insulating metal base circuit board that can efficiently arrange LED elements over a large area. Various electronic components are joined to the circuit on the insulating metal base circuit board through solder, conductive resin, or the like. However, the insulating metal base circuit board may exhibit a warping behavior due to a thermal load during the mounting process.

  For example, when an effort is made to reduce the thickness as the screen is enlarged as in a liquid crystal display device as shown in Patent Document 1, the insulating metal base circuit board is also reduced in thickness as the size is increased. Required.

  Non-Patent Document 1 describes that a plastic substrate warps, and describes that the warpage can be suppressed by improving the linear expansion coefficient and Young's modulus of the substrate.

In general, when a conductor circuit is formed on a substrate, the conductor circuit is usually formed in a portion to be used electrically, such as a circuit for supplying a driving current or a signal current or a circuit for applying a potential. Therefore, when the substrate is enlarged, as shown in FIG. 1, the area of the conductor circuit may be 20% or less with respect to the area of the entire substrate.
JP 2006-310014 A Sharp Technical Report No. 85 April 2003

  However, in the case of the known substrates as described above, there is a concern that the insulating metal base circuit substrate exhibits a warping behavior due to the thermal load during the mounting process, and that inconveniences such as insufficient bonding of solder and conductive resin may occur. Is done.

  That is, the object of the present invention is to reduce the warping behavior caused by the thermal load during the substrate mounting process, and to reliably bond the bonding material of the electronic component, and to provide a highly reliable insulated metal base circuit board. It is to provide a hybrid integrated circuit module using the above.

  According to the present invention, there is provided an insulated metal base circuit board in which a conductive metal is provided on a metal foil via an insulating layer, and the area of the conductive metal is 50% or more of the total area of the insulated metal base circuit board. And an insulating metal base circuit characterized in that, in at least one cross section passing through the center of gravity on the circuit surface side of the insulating metal base circuit board, the proportion of the circuit portion of the conductive metal is 5% or more and 50% or less. A substrate is provided.

  The insulated metal base circuit board having the above configuration can reduce the warping behavior caused by the thermal load during the mounting process of the board, and can firmly bond the bonding material of electronic components such as solder and conductive resin. it can.

  In addition, a hybrid integrated circuit module in which surface-mounted electronic components are mounted on an insulating metal base circuit board having the above-described structure can be applied to bonding materials such as solder and conductive resin and its peripheral parts even under severe temperature changes under actual use conditions. Less likely to crack.

  According to the present invention, it is possible to reduce the warping behavior caused by the thermal load during the mounting process of the substrate, to reliably bond the bonding material of the electronic component, and further, due to severe temperature changes that are received under actual use conditions. In addition, there are provided a bonding material such as solder or conductive resin, an insulating metal base circuit board that does not cause cracks in the periphery thereof, and a hybrid integrated circuit module using the insulating metal base circuit board.

<Explanation of terms>
In the present invention, the term “hybrid integrated circuit module” refers to a circuit board such as a metal base circuit board on which surface mount electronic components such as semiconductor elements, light emitting diode elements, chip resistors, chip capacitors, and the like are mounted. is there.

[Circuit part]
In the present invention, the “circuit portion” means a portion that is used electrically, such as a circuit for supplying a driving current or a signal current or a circuit for applying a potential.

[Circuit surface]
In the present invention, the “circuit surface” means a surface on which the circuit portion is formed on an insulating metal base circuit board. Further, the “center of gravity on the circuit surface side” is defined as a point where the force works when the thickness and weight of the surface are considered to be uniform and the gravity acting on each part of the substrate circuit surface is combined into one. For example, the center of gravity of the disk-shaped substrate is the same as the center, and the center of gravity of the triangular substrate is the point where the line connecting the vertex of the triangle and the midpoint of the opposite side intersects. The center of gravity of the polygonal substrate is first divided into a plurality of triangles by diagonal lines, and the center of gravity of the triangle is determined. Next, when the center of gravity of each triangle is obtained, it becomes the center of gravity of the polygonal substrate.

  The “cross section” means a cross section substantially perpendicular to the plane of the insulating metal base circuit board. That is, “at least one section passing through the center of gravity” means an arbitrary section passing through the center of gravity.

<Background of the invention>
The present inventor has disclosed a room temperature corresponding to a mounting process for a hybrid integrated circuit in which electronic components are joined by soldering in various thermal metal-plastic analysis using a finite element method by changing various circuit patterns of various insulating metal base circuit boards. Various calculations were performed to load heat in the range of to 250 ° C. As a result, when the metal base foil thickness of the insulating metal base circuit board is thin or the board size is large, the structure may warp due to the thermal load. It was found that the warpage can be reduced by using it not only as a circuit but also as a structural material.

  That is, the present invention is an insulating metal base circuit that can reduce the warping behavior due to the thermal load during the mounting process by controlling the arrangement configuration of the conductor circuit metal and using the conductor metal not only as a circuit but also as a structural material. This is based on the knowledge that a substrate and a hybrid integrated circuit module using the circuit substrate can be obtained.

  Hereinafter, embodiments of an insulating metal base circuit board and a hybrid integrated circuit module according to the present invention will be described with reference to the drawings.

<Embodiment 1>
FIG. 2 is a plan view showing an example of a hybrid integrated circuit module according to Embodiment 1 of the present invention. FIG. 3 is a cross-sectional view taken along line AA ′ in FIG. The insulating metal base circuit board constituting the hybrid integrated circuit module according to the present embodiment is provided with the insulating layer (A) 3 on one main surface of the metal foil 4, and the conductor metal on the insulating layer (A) 3. (Circuit part 2 and non-circuit part 7) are formed. The hybrid integrated circuit module according to the present embodiment has a structure in which the surface mount electronic component 1 is arranged and mounted on a desired portion of the insulating metal base circuit board via a bonding material 5.

  As shown in FIG. 2, the area of the circuit unit 2 and the non-circuit unit 7 according to this embodiment is 50% or more, preferably 60% or more, more preferably, the entire area of the circuit surface of the insulating metal base circuit board. 70% or more.

  The non-circuit portion 7 is formed as a structural material as shown in FIG. 2A, and the area of the circuit portion 2 and the non-circuit portion 7 is 50% or more of the entire area of the circuit surface of the insulating metal base circuit board, preferably 60. % Or more, more preferably 70% or more, to reduce the warping behavior of the insulating metal base circuit board due to the thermal load during the mounting process, and to improve the bonding reliability of solder or conductive resin as a bonding material I can do it.

  In the present embodiment, the larger the substrate is, the more effective the substrate is. The non-circuit portion 7 is formed as a structural material as shown in FIG. 2A, and the areas of the circuit portion 2 and the non-circuit portion 7 are formed. Is 50% or more of the total area of the circuit surface of the insulating metal base circuit board, the circuit portion 2 and the non-circuit portion 7 are in at least one arbitrary cross section passing through the center of gravity on the circuit surface side of the insulating metal base circuit board. Among these, the ratio of the circuit part (circuit part 2) is 5% or more and 50% or less, preferably 5% or more and 35% or less, and more preferably 5% or more and 25% or less. As a result, it is possible to reduce the warping behavior of the insulating metal base circuit board due to the thermal load during the mounting process, and to improve the bonding reliability of solder or conductive resin as a bonding material.

  In the present embodiment, the circuit portion (circuit portion 2) is a portion of the conductor metal formed on the insulating metal base circuit board through which a drive current and a signal current actually flow. The part other than 7.

  Next, each configuration of the hybrid integrated circuit module according to the present embodiment will be described.

[Circuit part]
In the present embodiment, the metal constituting the circuit unit 2 is not particularly limited, but includes any one of copper, aluminum, nickel, iron, tin, gold, silver, molybdenum, titanium, or two or more of these metals. An alloy, or a clad foil using the above metal or alloy can be used. In addition, the manufacturing method of the said circuit part 2 may be produced by the electrolytic method or the rolling method.

  Further, the circuit portion 2 may be subjected to metal plating such as Ni plating, Ni-Au plating, or solder plating.

  The thickness of the circuit part 2 is preferably 0.005 mm or more and 0.400 mm or less, more preferably 0.01 mm or more and 0.30 mm or less. If it is 0.005 mm or more, sufficient conductivity as a circuit board can be secured, and if it is 0.400 mm or less, a circuit can be formed efficiently at low cost.

[Non-circuit part]
In the present embodiment, the metal constituting the non-circuit portion 7 is not particularly limited, but any one of copper, aluminum, nickel, iron, tin, gold, silver, molybdenum, titanium, or two or more of these metals An alloy including the above, or a clad foil using the above metal or alloy can be used. In addition, the manufacturing method of the said non-circuit part 7 may be produced by the electrolytic method or the rolling method.

  The non-circuit portion 7 may be subjected to metal plating such as Ni plating, Ni—Au plating, or solder plating.

  The non-circuit portion 7 has a thickness of preferably 0.005 mm to 0.400 mm, and more preferably 0.01 mm to 0.30 mm. If it is 0.005 mm or more, sufficient conductivity as a circuit board can be secured, and if it is 0.400 mm or less, a circuit can be formed efficiently at low cost.

  The non-circuit portion 7 may be formed of the same material as the circuit portion 2 or may be another type of material. Moreover, the thickness may be the same as that of the circuit unit 2 or may be different. If the non-circuit portion 7 is made of the same material and the same thickness as the circuit portion 2, the non-circuit portion 7 can be manufactured simultaneously with the formation of the circuit.

[Insulating layer (A)]
The thermal conductivity of the insulating layer (A) 3 according to the present embodiment is 0.5 W / mK or more, preferably 1 W / mK or more, and more preferably 1.5 W / mK or more. An insulating metal base circuit board using an insulating layer having a thermal conductivity of 0.5 W / mK or more efficiently dissipates heat generated from electronic components to the back side of the insulating metal base circuit board, and further dissipates heat to the outside. As a result, it is possible to provide a long-life hybrid integrated circuit module while reducing the heat storage of the electronic component, reducing the temperature rise of the electronic component.

  Moreover, it is preferable to have a withstand voltage characteristic that the withstand voltage between the circuit part 2 and the metal foil 4 is 1 kV or more, desirably 1.5 kV or more, more desirably 2 kV or more. When the withstand voltage is 1 kV or more, the electronic component can be stably operated when the electronic component is mounted.

  Further, the insulating layer (A) 3 preferably has a product of a storage elastic modulus and a thermal expansion coefficient of 1 kPa / K to 10 MPa / K in a temperature range of 200 K to 450 K, and is preferably 10 kPa / K to 1 MPa / K. The following are particularly preferred: If the product of the storage elastic modulus and the coefficient of thermal expansion is 1 kPa / K or more, handling during production is easy, and if it is 10 MPa / K or less, the burden on the bonding material can be reduced.

  The thickness of the insulating layer (A) 3 is preferably 50 μm or more and 400 μm or less, and more preferably 80 μm or more and 200 μm or less. If it is 50 μm or more, sufficient electric insulation can be secured, and if it is 400 μm or less, heat dissipation can be sufficiently achieved, contributing to miniaturization and thickness reduction.

  The resin used for the insulating layer (A) 3 is not particularly limited and may be any resin as long as it is excellent in heat resistance and electrical insulation. From the viewpoint, a thermosetting resin is preferable. As the thermosetting resin, an epoxy resin, a phenol resin, a silicone resin, an acrylic resin, or the like can be used. In particular, the metal foil 4, the circuit unit 2, and the non-circuit unit 7 are included in the cured state while including an inorganic filler. The main component is a bifunctional epoxy resin excellent in bonding strength and insulation and a polyaddition type curing agent.

  As the polyaddition type curing agent, acid anhydrides and phenols excellent in mechanical and electrical properties are preferable, and the active hydrogen equivalent is 0. 0 with respect to the epoxy equivalent of the epoxy resin contained in the thermosetting resin. If it is 8 to 1 times, it is preferable because the mechanical and electrical properties of the insulating layer can be secured.

  Although it does not specifically limit as said epoxy resin, Epoxy resins which have flexibility, such as an epoxy resin which does not have flexibility, such as a bisphenol F type epoxy resin, and a dimer acid epoxy resin, can be used. Moreover, an epoxy resin previously modified with acrylic rubber or the like can also be used.

  As the curing agent, a flexible curing agent such as a phenolic resin or a flexible curing agent such as an aliphatic hydrocarbon diamine can be used, and these curing agents may be combined with an epoxy resin. Moreover, you may use a hardening accelerator as needed, and you may use resin components, such as a polyimide resin and a phenoxy resin, besides these hardening | curing agents.

  The specific epoxy resin is not particularly limited, and examples thereof include known epoxy resins such as naphthalene type, phenylmethane type, tetrakisphenolmethane type, biphenyl type, and bisphenol A alkylene oxide adduct type epoxy resins. Of these, an epoxy resin having a main chain having a polyether skeleton and a straight chain is preferable because of stress relaxation.

  The epoxy resin whose main chain has a polyether skeleton and has a main chain shape includes bisphenol A type, bisphenol F type epoxy resin, bisphenol A type hydrogenated epoxy resin, polypropylene glycol type epoxy resin, polytetramethylene glycol type Aliphatic epoxy resins typified by epoxy resins, polysulfide-modified epoxy resins and the like can be mentioned, and a plurality of these can be used in combination.

  When high heat resistance is required for an insulating metal base circuit board, the bisphenol A type epoxy resin is used alone or in combination with other epoxy resins, so that both electrical insulation and thermal conductivity are high and heat resistance is high. A cured resin can be obtained.

  The bisphenol A type epoxy resin preferably has an epoxy equivalent of 300 or less. This is because if the epoxy equivalent is 300 or less, it is possible to prevent a decrease in Tg due to a decrease in crosslink density, which is observed when the polymer type is obtained, and hence a decrease in heat resistance. Moreover, if molecular weight is large, it will become easy to blend an inorganic filler in curable resin, and a uniform resin composition will be obtained.

  The epoxy resin preferably has a hydrolyzable chlorine concentration of 600 ppm or less. If the hydrolyzable chlorine concentration is 600 ppm or less, sufficient moisture resistance as a metal base circuit board can be obtained.

  Moreover, you may add a hardening | curing agent to the said epoxy resin. As the curing agent, one or more selected from the group consisting of aromatic amine resins, acid anhydride resins, phenol resins, and dicyanamide can be used.

  About the addition amount of the said hardening | curing agent, it is preferable that it is 5-50 mass parts with respect to 100 mass parts of epoxy resins, and it is more preferable that it is 10-35 mass parts.

  Furthermore, a curing catalyst can be used for the epoxy resin as necessary. As the curing catalyst, an imidazole compound, an organic phosphate compound, a tertiary amine, a quaternary ammonium, or the like is generally used, and any one or more types can be selected.

  Although there is no restriction | limiting in particular about addition amount, since it changes with hardening temperature, It is preferable that it is 0.01 to 5 mass parts with respect to 100 mass parts of epoxy resins. If it is 0.01 mass part or more, it will fully harden | cure, and if it is 5 mass parts or less, control of the hardening degree in a circuit board manufacturing process will become easy.

  As long as it does not contradict the objective of this invention, the said insulating layer (A) 3 adds well-known various adjuvants, such as dispersion | distribution adjuvants, such as a coupling agent, and viscosity adjustment adjuvants, such as a solvent. Is possible.

  The inorganic filler contained in the insulating layer (A) 3 is preferably an electrically insulating and heat conductive material, such as silicon oxide, aluminum oxide, aluminum nitride, silicon nitride, boron nitride, magnesium oxide. Etc. are used. These inorganic fillers can be used alone or in combination.

  Of these, aluminum nitride and boron nitride are preferred because of their high thermal conductivity. Further, the use of silicon oxide or boron nitride makes it possible to keep the dielectric constant of the cured body low, and it is preferable because it is easy to ensure electrical insulation when used as a heat dissipation material for electric and electronic parts used at high frequencies. Furthermore, in order to improve handling property and fluidity, the particle shape of the inorganic filler preferably has an aspect ratio close to 1. When coarse particles and fine particles are mixed together, it is possible to achieve a higher packing than when crushed particles or spherical particles are used alone, which is more preferable.

  As the inorganic filler, a plurality of particle groups such as coarse particles and fine particles can be mixed and used for the purpose of improving the heat conduction characteristics of the insulating layer. For example, when using a mixture of coarse particles and fine particles, it is preferable to use coarse particle powder having an average particle diameter of 5 μm or more and fine particle powder of less than 5 μm. The ratio of the coarse particle powder to the fine particle powder is preferably 40 to 98% by volume, more preferably 50 to 96% by volume, with respect to the whole inorganic filler.

  The amount of the inorganic filler added is preferably 40% by volume or more and 75% by volume or less in the resin composition forming the insulating layer (A) 3. If it is 40 volume% or more, sufficient heat dissipation can be ensured, and if it is 75 volume% or less, good dispersibility, adhesion and voltage resistance in the resin can be obtained.

  Moreover, it is preferable that the sodium ion concentration in the said inorganic filler is 500 ppm or less, and it is more preferable that it is 100 ppm or less. When the sodium ion concentration in the inorganic filler is 500 ppm or less, the migration of ionic impurities does not occur at high temperature and under direct current voltage, and good electrical insulation can be maintained.

[Metal foil]
The metal foil 4 according to the present embodiment is not particularly limited, and is made of aluminum, iron, copper, an alloy of these metals, or a clad material thereof, and any of them may be used, but considering heat dissipation, aluminum, Copper or an alloy thereof is preferred. Further, if necessary, surface treatment such as sandblasting, etching, various plating treatments, coupling agent treatment, etc. is performed on the adhesive surface side with the insulation layer in order to improve the adhesion with the insulation layer (A) 3. You may give it.

  Furthermore, the metal foil 4 may be formed into a circuit by using the technique for forming the conductive metal described above. Thereby, a double-sided substrate having circuits on both sides of the insulating layer can be obtained.

  The thickness of the metal foil 4 is preferably 0.013 mm or more, and more preferably 0.05 mm or more. If it is 0.013 mm or more, wrinkles will not occur during handling, and if it is 0.5 mm or more, it is suitable as a circuit board on which an LED for a backlight of a liquid crystal device is mounted. The upper limit value of the thickness of the metal foil 4 is not technically limited. However, if the thickness of the metal foil exceeds 3 mm, an application as an insulating metal base circuit board cannot be found and it is not practical.

<Embodiment 2>
Next, an insulated metal base circuit board and a hybrid integrated circuit module according to another embodiment of the present invention will be described. Each configuration is the same as that of the first embodiment.

  FIG. 3 is a cross-sectional view illustrating another example of the hybrid integrated circuit module according to the second embodiment. The insulating metal base circuit board according to the present embodiment has an insulating layer (A) 3 provided on one main surface of the metal foil 4, and a conductive metal (circuit portion 2 and non-circuit) on the insulating layer (A) 3. Part 7) is formed, and an insulating film (insulating layer (B) 6) is arranged on the circuit part 2, the non-circuit part 7 and the insulating layer (A) 3 other than the part where the bonding material 5 is provided. Have. The hybrid integrated circuit module according to the present embodiment has a structure in which the surface mount electronic component 1 is disposed and mounted on a desired portion of a circuit of an insulating metal base circuit board via a bonding material 5.

[Insulating layer (B)]
The total thickness of the insulating layer (B) 6 according to this embodiment is sufficient if it is about 10 to 500 μm. However, the thickness of 10 to 100 μm is preferable because it has an advantage that an insulating metal base circuit board can be manufactured with high productivity. .

  The resin used for the insulating layer (B) 6 is an epoxy resin in the case of a thermosetting solder resist, an acrylic resin in the case of an ultraviolet curable solder resist, and an epoxy resin in the case of an ultraviolet / heat combined solder resist. Use in combination with an acrylic resin is desirable.

  The insulating layer (B) 6 may be a white film. In this way, the reflectance of the substrate itself is increased, and the hybrid integrated circuit module itself can be used as a planar light source by combining with a light source such as an LED element. The planar light source can be used as various illuminations, and as a backlight for various liquid crystal panels used in televisions, personal computers, mobile phones and the like.

  The white film has a reflectance of 70% or more with respect to a visible light region of 400 to 800 nm. In a more preferred embodiment, the white film has a reflectance of 80% or more with respect to 450 to 470 nm, 520 to 570 nm, and 620 to 660 nm. It is preferable to have a rate.

  Specifically, the white film can be obtained by blending a white pigment into a resin composition containing a photocurable resin or a thermosetting resin. Epoxy resins, acrylic resins, and mixtures thereof are preferably used as the photocurable resin and thermosetting resin, but are not limited thereto.

  The white pigment contained in the white film preferably contains at least one selected from zinc oxide, calcium carbonate, titanium dioxide, aluminum oxide, and smectite.

  Of the white pigments, titanium dioxide has the highest refractive index and is more preferable when used to increase the light reflectance of the substrate. Titanium dioxide is known to have anatase and rutile crystal systems, but the rutile type is superior in stability and has a weak photocatalytic action, and the deterioration of the resin component is suppressed compared to other structures. Therefore, it can be used suitably.

  Furthermore, what surface-treated titanium dioxide and suppressed photocatalytic action can be used suitably. Typical examples of the surface treatment include coating with silicon dioxide, aluminum hydroxide or the like. Further, regarding titanium dioxide, the average particle diameter is preferably 0.30 μm or less in order to increase the light scattering efficiency.

  Among the white pigments, zinc oxide is a material having both a high refractive index and a high heat dissipation property, and is more preferable when used to increase the reflectance and the heat dissipation property of the substrate. Moreover, when improving the light scattering efficiency of zinc oxide, it is preferable that an average particle diameter is 0.35 micrometer or less.

  The amount of white pigment added to the insulating layer (B) 6 is preferably 5 to 50% by volume, more preferably 5 to 30% by volume, based on the entire insulating layer. If it is 5 volume% or more, the effect of a sufficient reflectance improvement will be acquired, and if it is 50 volume% or less, appropriate dispersibility can be secured in the operation of forming the insulating layer.

  In the case where the insulating layer (B) 6 is formed on the circuit portion 2, an opening portion is provided in advance in a portion corresponding to a joint portion of an electronic component such as an LED or a connector joint portion by masking or the like. What is necessary is to respond.

  From the viewpoint of adhesiveness with the insulating layer (B), the surfaces of the circuit part 2 and the non-circuit part 7 on the side in contact with the insulating layer (B) 6 are sandblasted, etched, various plating treatments, and a coupling agent treatment. A surface treatment such as the above can also be selected as appropriate.

  In the hybrid integrated circuit module having the above configuration, the insulating layer (B) is formed on the circuit portion 2, the non-circuit portion 7 or the insulating layer (A) 3, and the insulating layer (B) includes an LED element and a chip. When an electronic component such as a resistor or a chip capacitor is fixed by a bonding material such as solder or conductive resin, it is also used as a solder resist for specifying the location of the bonding material. Furthermore, since the insulating layer (B) is a white film, the reflectance with respect to light becomes high, and it can also be used as a planar light source by combining with a light source such as an LED element. Such a planar light source can be used as various illuminations, and as a backlight for various liquid crystal panels such as televisions, personal computers and mobile phones.

<Manufacturing method>
Next, an insulating metal base circuit board according to this embodiment and a method for manufacturing a hybrid integrated circuit module using the same will be described.

  In the method for manufacturing an insulating metal base circuit board according to this embodiment, one or a plurality of insulating materials obtained by appropriately adding an additive such as a curing agent to a resin containing an inorganic filler are prepared, and the metal foil 4 and / or the conductor are prepared. While applying a single layer or multiple layers on metal foil (circuit part 2 and non-circuit part 7), it is cured by irradiation with light such as ultraviolet rays or heat treatment as necessary, and then applied to the metal foil. A method of forming a circuit by performing a process such as etching can be applied.

  Alternatively, a sheet made of an insulating material (corresponding to the insulating layer (A) 3) is prepared in advance, and the metal that becomes the metal foil 4 or the conductive metal (the circuit portion 2 and the non-circuit portion 7) through the sheet. A method of forming a circuit by etching or the like after laminating the foils can also be applied.

  Furthermore, when forming an insulating film (insulating layer (B) 6) as in the second embodiment, a solder resist or white film to be the insulating layer (B) 6 is applied on the insulating metal base circuit board, What is necessary is just to cure by irradiating light, such as an ultraviolet-ray, or heat processing. At this time, the circuit portion to which the bonding material for the surface mount component is bonded is masked so that no coating film is formed.

  In order to obtain a hybrid integrated circuit module using the above insulating metal base circuit board, a surface mount component or the like may be bonded using a bonding material at a desired position.

  According to the insulating metal base circuit board and the manufacturing method of the hybrid integrated circuit module using the same according to the present embodiment, even when the board size is increased or the board thickness is reduced, the mounting process is performed. The warpage behavior caused by the heat load of the electronic component can be reduced, and the bonding material of the electronic component can be securely bonded. A high hybrid integrated circuit module can be provided.

<Effect>
The insulated metal base circuit board having the above configuration can reduce the warping behavior caused by the thermal load during the mounting process of the board, and can securely bond the bonding material of the electronic component. Even when the temperature is severely changed, cracks do not occur in the bonding material such as solder and conductive resin and its peripheral portion.

  An insulating film may be formed on the insulating layer and the conductive metal. In this way, in addition to the conventional printed circuit board function of mounting electronic components, it has a new function of light reflection function.

  Further, the insulating film may have a minimum reflectance of light having a wavelength of 400 to 800 nm of 70% or more. In this way, it can be preferably used for a liquid crystal display device such as a personal computer or a television.

  Further, the reflectance of light having wavelengths of 460 nm, 525 nm, and 620 nm may be 80% or more in the insulating film. When the reflectance of light of the above three wavelengths is 80% or more, it can be preferably used for a backlight of a liquid crystal display device that requires high color rendering properties.

  Furthermore, by mounting various electronic components on the above insulating metal base circuit board, cracks may occur in the bonding material such as solder and conductive resin and its peripheral parts even under severe temperature changes under actual use conditions. A hybrid integrated circuit module can be obtained.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to these. For example, the hybrid integrated circuit module is used by being fixed to a housing, but may be attached to various resin cases made of PPS (polyphenylene sulfide) or the like, or may be embedded in an epoxy resin or the like. .

  In the present invention, the conductor metal or metal foil may be a single metal foil or a clad foil in which two or more metal layers are laminated. Absent.

  Further, the electronic component may be provided in one circuit unit, or one electronic component may be provided over two or more circuit units.

  Furthermore, in the present invention, the insulating layer is composed of one or more unit insulating layers, and the unit insulating layer may be a single layer or a plurality of unit insulating layers. The insulating layer preferably contains various inorganic fillers in order to maintain high heat dissipation of the circuit board. In addition, when the insulating layer has a multilayer structure, it is composed of at least two or more types of unit insulating layers in which the type of resin, the type of inorganic material, the type of additive to the resin, or the quantitative ratio thereof is changed. Has been. For example, when the unit insulating layer is composed of three or more layers, even if any unit insulating layer has a different composition, adjacent unit insulating layers have different compositions and non-adjacent unit insulating layers have the same composition. It does not matter.

  Furthermore, in the present invention, the bonding material may be solder or conductive resin, as long as it joins an electronic component and a circuit member, but when the bonding material is solder, This is preferable because the bonding force between the component and the metal base circuit board is high, and thus the heat generated from the electronic component is easily dissipated. When the bonding material is solder, the solder may be various binary and ternary solders containing lead-tin, but various binary and ternary solders not containing lead, such as gold, silver, and copper. , Solder containing tin, zinc, bismuth, indium, antimony, or the like.

  Further, when the bonding material is a conductive resin, even if the epoxy or acrylic resin contains one kind of metal such as gold, silver, copper, or a conductive material such as graphite, the conductive material such as these metals or graphite can be used. It may contain two or more kinds of functional materials.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

<Examples 1-12, Comparative Examples 1-6>
On a copper foil (metal foil 4) having a thickness of 35 μm, phenol novolak (manufactured by Dainippon Ink & Chemicals, Inc.) as a curing agent with respect to 100 parts by mass of a bisphenol A type epoxy resin (manufactured by Japan Epoxy Resin, “EP-828”). , "TD-2131") is added, and crushed coarse particles of silicon oxide (manufactured by Tatsumori Co., "A-1") with an average particle size of 1.2 µm and crush with an average particle size of 10 µm The silicon oxide of the coarse particles (manufactured by Tatsumori Co., Ltd., “5X”) is combined so as to be 56% by volume in the insulating layer (mass ratio of spherical coarse particles and spherical fine particles is 7: 3). A coating layer (insulating layer (A) 3) was formed so as to have a thickness of 150 μm. Next, a 200 μm thick copper foil was laminated, and the coating layer was cured by heating to obtain an insulating metal base substrate.

  Further, after the copper foil is etched by masking a predetermined position with an etching resist, the etching resist is removed to form a copper circuit (circuit part 2) and a non-circuit copper metal (non-circuit part 7), and the insulation. The maximum rectangular shape that can be taken in the plane of the metal base circuit board was an insulating metal base circuit board having a size of 350 mm × 350 mm. At this time, several types of masks having various patterns were used as examples and comparative examples. For example, the pattern of FIG. 1 is Example 3, and the pattern of FIG.

  About the insulated metal base circuit board of each Example and a comparative example, the ratio which the area of a conductor metal (the circuit part 2 and the non-circuit part 7) occupies for a board | substrate area, at least 1 arbitrary arbitrary passing through the gravity center by the side of the circuit surface of a circuit board Table 1 shows the ratio of the area of the circuit portion to the area of the conductor metal in the cross section.

  A white solder resist was applied on the insulating metal base circuit board, and a white film was formed by ultraviolet irradiation. At this time, no white film was formed on the bonding material portion on the copper circuit.

  Next, as a mounting process test, a surface mounting type connector of ERNI was bonded to each circuit board pad obtained by the above operation with a bonding material to obtain a hybrid integrated circuit module.

  In Examples 1 to 8 and Comparative Examples 1 to 4, solder made of tin-copper-silver was used and soldered by reflow at a temperature of 550K. Further, Examples 9 to 12 and Comparative Examples 5 and 6 were joined by reflow using a conductive adhesive made of silver-epoxy at a temperature of 385K.

(Measurement of warpage)
After the bonding, the hybrid integrated circuit module was placed on a horizontal table, the height of each part of the substrate from the table was measured, and the highest value was taken as the maximum amount of warpage. The results are shown in Table 2.

(Observation of bonding state)
In addition, the connector solder was observed for bonding defects. The results are shown in Table 3.

(Observation of cracks)
Further, for each of the above hybrid integrated circuit modules, a heat cycle test was performed in which the operation of holding at 233 K for 7 minutes and holding at 423 K for 7 minutes in the liquid phase was processed a predetermined number of times as one cycle. After the test, each hybrid integrated circuit was observed with an optical microscope mainly for the occurrence of cracks at the joint. The results are shown in Table 3.

<Discussion>
As can be seen from the results in Table 2, the maximum warpage amount of Examples 1 to 12 is 1/2 or less that of Comparative Examples 1 to 6, and the hybrid integrated circuit module according to the present invention can reduce the warpage of the substrate. It is clear that it is excellent.

  In addition, as can be seen from the results in Table 3, in Comparative Examples 2 to 4, defective bonding was recognized, but in Examples 1 to 12, it was confirmed that there was no abnormality, and the hybrid integrated circuit module according to the present invention was It is clear that it is excellent. Further, in Comparative Examples 1 to 6, most of the cracks were observed after 500 heat cycle tests, whereas in Examples 1 to 12, there were few cracks even in 500 heat cycles. confirmed. It is clear that the hybrid integrated circuit module according to the present invention is excellent in crack resistance.

  The insulating metal base circuit board and the hybrid integrated circuit module using the insulating metal base circuit board according to the present invention are free from bonding defects in the mounting process, and further, due to severe temperature changes under actual use conditions, It is industrially useful because it does not cause cracks in the periphery and has high reliability.

FIG. 3 is a schematic plan view of a conventional hybrid integrated circuit module. 1 is a schematic plan view of a hybrid integrated circuit module according to Embodiment 1 of the present invention. FIG. 3 is a schematic cross-sectional view taken along line A-A ′ in FIG. 2. Sectional schematic of the hybrid integrated circuit module which concerns on Embodiment 2 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Surface mount electronic component 2 Circuit part 3 Insulation layer (A)
4 Metal foil 5 Bonding material 6 Insulating layer (B)
7, a non-circuit portion AA ′ cross section passing through the center of gravity from the end of the insulating metal base circuit board

Claims (5)

An insulating metal base circuit board in which a conductive metal is provided on a metal foil via an insulating layer,
The area of the conductor metal is 50% or more of the entire area of the circuit surface of the insulating metal base circuit board;
The insulating metal base circuit board is characterized in that, in at least one cross section passing through the center of gravity on the circuit surface side of the insulating metal base circuit board, a ratio of a circuit portion of the conductive metal is 5% or more and 50% or less.   The insulating metal base circuit board according to claim 1, wherein an insulating film is formed on the insulating layer and the conductive metal. The metal base circuit board according to claim 2, wherein the insulating film has a minimum reflectance of 70% or more for light having a wavelength of 400 to 800 nm. 3. The metal base circuit board according to claim 2, wherein the insulating film has a reflectance of light of wavelengths of 460 nm, 525 nm, and 620 nm of 80% or more. A hybrid integrated circuit module comprising the insulating metal base circuit board according to claim 1.

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