JP2009302188A - Insulated metal base circuit board and hybrid integrated circuit module using the same - Google Patents

Abstract

An insulating metal base circuit board and a hybrid integrated circuit module using the circuit board for reducing the warping behavior caused by a thermal load during the substrate mounting process are provided.
An insulating metal base circuit board in which a conductor circuit is provided on a metal foil via an insulating layer, wherein the conductor circuit metal is formed around the circuit surface of the insulating metal base circuit board. Insulating metal base circuit board and hybrid integrated circuit module using the circuit board.
[Selection] Figure 1

Description

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

  Conventionally, various circuit boards have been used to realize surface mounting that enables miniaturization and labor saving during mounting, and hybrid integrated circuits in which various surface mount electronic components are mounted on these circuit boards. Module is 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 such an insulating metal base circuit board via solder, conductive resin, or the like.

  For example, when an effort is made to reduce the thickness as the screen is enlarged as in a liquid crystal display device application as disclosed 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.

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.

  The present invention has been made in view of the above circumstances, reduces the warping behavior caused by the thermal load during the mounting process of the substrate, can reliably bond the bonding material of the electronic component, reliable An object of the present invention is to provide a high insulating metal base circuit board and a hybrid integrated circuit module using the same.

  According to the present invention, there is provided an insulating metal base circuit board in which a conductor circuit is provided on a metal foil via an insulating layer, and there is a belt-like region along the outer periphery of the circuit surface of the insulating metal base circuit board. The band-like region in the cross section of any insulated metal base circuit board perpendicular to the circuit plane passing through the center of gravity of the circuit plane is separated from one end of the circuit plane in the cross section by 0.2 / 100 times the width of the circuit plane in the cross section. Insulated metal base circuit board characterized in that the occupation ratio of the conductor circuit installation area in the belt-shaped area is 60% or more. The

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

  In addition, according to the present invention, there is provided a hybrid integrated circuit module characterized by using the above insulating metal base circuit board.

  The hybrid integrated circuit module having this configuration can reduce the warping behavior caused by the thermal load during the substrate mounting process, and can firmly bond the bonding material of electronic components such as solder and conductive resin. Since the insulating metal base circuit board is used, cracks are less likely to occur in the bonding material such as solder and conductive resin and its peripheral part even under severe temperature changes under actual use conditions.

  According to the present invention, it is possible to reduce the warpage behavior caused by the thermal load during the mounting process of the insulating metal base circuit board, and it is possible to firmly bond the bonding material for electronic components such as solder and conductive resin. .

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

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

[Striped area]
In the present invention, the “band-like region” means a band-like region having a substantially constant width. As a matter of course, the “band-like region” includes a band-like region that forms a ring in a topological sense as a whole.

[Rectangular shape]
In the present invention, the “rectangular shape” means a so-called rectangular shape. As a matter of course, the “rectangular shape” includes a so-called square shape.

[Rectangular shape with the largest area inscribed on the outer periphery of the circuit surface]
In the present invention, the “maximum rectangular shape inscribed in the outer periphery of the circuit surface” of the insulated metal base circuit board means the largest rectangular shape that can be taken in the insulated metal base circuit board as illustrated in FIG. . That is, when all rectangular shapes inscribed inside the outer periphery of the circuit surface of the insulating metal base circuit board are drawn, the rectangular shape having the largest area among the rectangular shapes is meant. In addition, when there are a plurality of rectangular shapes having the maximum area, a rectangular shape having an arbitrary maximum area can be selected.

[cross section]
In the present invention, the “cross section” of an insulating metal base circuit board refers to a cross section of the insulating metal base circuit board cut along a plane perpendicular to the circuit surface passing through the center of gravity of the circuit surface of the insulating metal base circuit board. Means.

[Occupancy]
In the present invention, the “occupancy ratio” of the conductor circuit means a relative ratio of the total area of the conductor circuit installation area to the entire area of the band-like area.

<Background of the invention>
In the thermoelastic-plastic analysis using the finite element method, the present inventors correspond to the mounting process for a hybrid integrated circuit in which electronic components are joined by solder by changing various circuit patterns of various insulating metal base circuit boards. Various calculations were performed to load heat ranging from room temperature 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, warping occurs due to the thermal load on the structure, however, by devising the circuit design method, It has been found that warpage can be reduced.

  That is, the present inventors have reduced the warpage behavior due to the thermal load during the mounting process of the thinned and enlarged insulating metal base circuit board, and improved the circuit design method for improving the bonding reliability of solder and conductive resin. In order to find an insulating metal base circuit board using the same and a hybrid integrated circuit module using the circuit board, as a result of intensive studies on mounting methods, circuit board structures, and materials, the circuit arrangement configuration and outer shape of the insulating metal base circuit board are determined. It was found that when controlled, a circuit board capable of reducing the warping behavior due to the thermal load during the mounting process can be obtained.

  That is, the present invention provides an insulating metal base circuit board that can reduce the warping behavior due to a thermal load during the mounting process by controlling the arrangement configuration and outer shape of the conductor circuit metal, and a hybrid integrated circuit module using the circuit board. It is based on the knowledge that it is possible. That is, the circuit design method adopted by the present invention is to control the arrangement configuration of the conductor circuit metal, and to bring the outer shape of the insulating metal base circuit board close to a simple shape.

  And, as a result of various experimental studies based on the above knowledge, the present inventor has formed a conductor circuit metal around the insulating metal base circuit board circuit surface, thereby increasing the size of the substrate. Alternatively, it has been found that even when the substrate thickness is reduced, the warping behavior caused by the thermal load during the mounting process can be reduced, and the bonding material of the electronic component can be reliably bonded.

  And when this inventor produced the hybrid integrated circuit module using said insulating metal base circuit board, even under the actual use, it does not produce a peeling-off at the peripheral part, and has a feature with high reliability. It has been found that a hybrid integrated circuit module having the above can be obtained. That is, the inventor of the present invention has a specific structure in advance so that the above-described insulating metal base circuit board can easily obtain a characteristic hybrid integrated circuit module. The module has been found to be able to easily achieve highly reliable characteristics without causing cracks in the bonding material such as solder and conductive resin and its peripheral parts even under severe temperature changes under actual use conditions. I let you.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same reference numerals are given to the same components, and the description will be omitted as appropriate.

<Embodiment 1>
First, representative embodiments of an insulated metal base circuit board and a hybrid integrated circuit module according to the present invention will be described. FIG. 1 is a schematic plan view showing an example of an insulated metal base circuit board according to this embodiment. FIG. 2 is a schematic cross-sectional view of the hybrid integrated circuit module according to this embodiment. In the insulated metal base circuit board of the present embodiment, the insulating layer (A) 3 is provided on one main surface of the metal foil 4, and the conductor circuit 2 is formed on the insulating layer (A). The hybrid integrated circuit module has a structure in which the surface mount electronic component 1 is arranged and mounted on a desired portion of an insulating metal base circuit board via a bonding material 5. That is, the insulated metal base circuit board according to the present embodiment is an insulated metal base circuit board in which the conductor circuit 2 is provided on the metal foil 4 via the insulating layer (A) 3.

  In this embodiment, as illustrated in FIGS. 1 and 2, a conductor circuit 2 made of a metal material is formed around the insulating metal base circuit board circuit surface. That is, in the insulated metal base circuit board according to the present embodiment, there is a belt-like region along the outer periphery of the circuit surface of the insulated metal base circuit substrate, and the conductor circuit 2 is provided in this belt-like region. . Thereby, the complicated curvature of the board | substrate at the time of a heating etc. can be controlled, and the joining defect of the joining material in a mounting process can be eliminated.

  Here, the periphery of the circuit board circuit surface means 0.4 Ws / 100 to 10 Ws / 100, where Ws is the length of the cross section passing through the center of gravity from the end of the insulating metal base circuit board. That is, in the insulated metal base circuit board according to the present embodiment, the periphery of the circuit board circuit surface has a predetermined width sandwiched between two annular lines separated by a predetermined distance from the end of the insulated metal base circuit board. It can be said that it is a belt-like region. The predetermined distance and the predetermined width in the band-like region are defined as a relative value with respect to Ws, which is the length of the cross section passing through the center of gravity from the end of the insulating metal base circuit board.

  A method of defining the predetermined distance and the predetermined width will be specifically described. First, in the cross section of an arbitrary insulated metal base circuit board perpendicular to the circuit surface passing through the center of gravity of the circuit surface, the width of the circuit surface in the cross section of the insulated metal base circuit board is defined as Ws. In this case, the cross-section of the band-shaped region has a position (the position of the inner annular line) separated by 0.2 / 100 times Ws from one end of the circuit surface in the cross-section of the insulating metal base circuit board and 10/100. This corresponds to a region sandwiched between positions separated by a distance (position of the outer annular line). If it prescribes | regulates in this way, if the length of the cross section which passes along a gravity center from the edge of an insulated metal base circuit board is set to Ws, the strip | belt-shaped area | region of the said circuit board circuit surface will be 0.4Ws / 100-10Ws / 100. Will be in range.

  The conductor circuit does not necessarily have to be formed over the entire area around the insulating metal base circuit board circuit surface, and the conductor circuit 2 is formed in an area of 60% or more around the insulating metal base circuit board circuit surface. It only has to be.

  That is, in the insulated metal base circuit board according to the present embodiment, the occupation ratio of the installation area of the conductor circuit 2 in the belt-like area may be 60% or more. In addition, this occupation rate becomes like this. Preferably it is 70% or more, More preferably, it is 80% or more. This is because if the occupation ratio of the installation area of the conductor circuit 2 in the belt-like area is 60% or more, it is possible to control the complicated warpage of the substrate during heating or the like and eliminate the bonding failure of the bonding material in the mounting process.

  In order to prevent discharge of the edge surface, a region without the conductor circuit 2 of about 0.2 Ws / 100 to 2 Ws / 100 may be provided. That is, in the insulated metal base circuit board according to the present embodiment, there may be a second belt-like region where the conductor circuit 2 is not installed. It is preferable that the second belt-like region exists on the outside of the belt-like region where the conductor circuit 2 is installed, partially overlapping or isolated from the belt-like region where the conductor circuit 2 is installed.

  In other words, the second band-shaped region has one end of the circuit plane in the cross section and the width of the circuit plane in the cross section from the one end in the cross section of any insulating metal base circuit board perpendicular to the circuit plane passing through the center of gravity of the circuit plane. This corresponds to a region sandwiched between positions separated by 0.2 / 100 times or more and 2/100 times or less of Ws. As described above, a conductor circuit having a width of 0.2 / 100 times or more and 2/100 times or less of the width Ws of the circuit surface outside the band-like region where the conductor circuit 2 on the circuit surface of the insulating metal base circuit board is installed. By providing the second belt-like region without 2, it is possible to prevent the edge surface of the insulating metal base circuit board from being discharged.

  Here, a rectangular shape having the maximum area inscribed on the outer periphery of the circuit surface of the insulating metal base circuit board can be drawn. In the rectangular insulated metal base circuit board as shown in FIG. 1 in the present embodiment, the maximum rectangular shape that can be taken in the insulated metal base circuit board matches the insulated metal base circuit board.

  In the insulated metal base circuit board according to the present embodiment, when the largest rectangular shape that can be taken in the insulated metal base circuit board is taken, the ratio of the area of the rectangular shape to the entire planar area of the insulated metal base circuit board is It is preferable that it is 60% or more. That is, the proportion of the rectangular insulating metal base circuit board is 60% or more, preferably 70% or more, and more preferably 90% or more. As a result, uniform warpage can be induced, and complex warpage can be controlled to eliminate bonding failure of the bonding material in the mounting process.

Next, each configuration of the insulated metal base circuit board according to the present embodiment will be described.

[Conductor circuit]
The conductor circuit 2 used for the insulated metal base circuit board according to the present embodiment is composed of a clad foil in which two or more metal layers are laminated, even if the conductor circuit 2 is composed of a single metal foil. It doesn't matter what you have.

  The metal constituting the conductor circuit 2 is any one of copper, aluminum, nickel, iron, tin, gold, silver, molybdenum, titanium, an alloy containing two or more of these metals, or the above metal or alloy. The used clad foil or the like can be used. In addition, the manufacturing method of said metal foil may be produced by an electrolytic method or a rolling method.

  Further, metal plating such as Ni plating, Ni—Au plating, solder plating, or the like may be applied on the metal foil constituting the conductor circuit 2.

  The thickness of the conductor circuit 2 is 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, a sufficient conduction circuit as a circuit board can be secured, and if it is 0.400 mm or less, circuit formation can be performed efficiently at low cost.

[Insulating layer (A)]
The insulating layer (A) 3 used in the present embodiment is not particularly limited, and is not intended to exclude an insulating layer made of an inorganic material or the like, but is an insulating resin from the viewpoints of moldability, flexibility, insulating properties, and the like. An insulating layer made of the composition is preferred.

  The insulating layer (A) 3 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 (A) 3 preferably contains various inorganic fillers in order to maintain high heat dissipation of the circuit board. Further, when the insulating layer (A) 3 has a multilayer structure, at least two or more types of units 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 are used. It is preferable that it is composed of an insulating layer. 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.

  The thermal conductivity of the insulating layer (A) 3 used in this 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 conductor circuit 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 adhesive strength and insulation with the metal foil 4 and the conductor circuit 2 in a cured state while including an inorganic filler. The main component is a bifunctional epoxy resin having excellent properties 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.

  About the said bisphenol A type epoxy resin, it is still more preferable that the epoxy equivalent is 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 an insulating 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 the 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 used in the present embodiment is not particularly limited, and is made of aluminum, iron, copper, or 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. In addition, in order to improve the adhesion with the insulating layer (A) 3 as 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. May be.

  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 (A) 3 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 of the thickness of the metal foil 4 is not technically limited. However, if the thickness of the metal foil 4 exceeds 3 mm, an application as an insulating metal base circuit board cannot be found, and it is not practical.

[Others]
The area of the planar shape of the insulating metal base circuit board according to the present embodiment may be 2 × 10 ⁴ mm ² or more, particularly 6 × 10 ⁴ mm ² or more. In this way, when the area of the planar shape is 2 × 10 ⁴ mm ² or more or 6 × 10 ⁴ mm ² or more, the structure is likely to warp due to a thermal load, but the insulated metal base according to the present embodiment This is because the warpage can be reduced by devising a circuit design method like a circuit board. On the other hand, the area of the planar shape is not particularly limited, but is usually 2 × 10 ⁶ mm ² or less because of restrictions on the manufacturing process.

  In the present embodiment, the conductor circuit 2 and the metal foil 4 may be different metal materials or alloy materials. For example, the conductor circuit 2 may be made of copper or a copper alloy, and the metal foil 4 may be made of aluminum or an aluminum alloy. As described above, when the materials of the conductor circuit 2 and the metal foil 4 are different, warpage is likely to occur due to a thermal load due to the difference in linear expansion coefficient, etc., but the insulated metal base circuit board according to the present embodiment This is because the warpage can be reduced by devising the circuit design method as described above.

  In the present embodiment, as a bonding material for bonding various electronic components onto the conductor circuit 2, whether solder or conductive resin, the electronic component and the circuit material of the conductor circuit 2 are bonded. However, when the bonding material is solder, the bonding strength between the electronic component and the conductor circuit 2 of the insulated metal base circuit board is high, and therefore heat generated from the electronic component is easily dissipated, which is preferable. . 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.

  When the bonding material is a conductive resin, even if the epoxy or acrylic resin contains one kind of conductive material such as metal such as gold, silver or copper, or graphite, conductive material such as these metal or graphite It may contain two or more types.

<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 schematic plan view showing an example of an insulated metal base circuit board according to the present embodiment. FIG. 4 is a schematic cross-sectional view showing an example of a hybrid integrated circuit module according to this embodiment. The insulating metal base circuit board of this embodiment is provided with the insulating layer (A) 3 on one main surface of the metal foil 4, the conductor circuit 2 is formed on the insulating layer (A), and a bonding material is used. The insulating layer (B) 6 is arranged on the circuit portion and the insulating layer (A) that are not to be used. The hybrid integrated circuit module of the present embodiment has a structure in which the surface mount electronic component 1 is arranged and mounted on a desired portion of the conductor circuit 2 of the insulating metal base circuit board via the bonding material 5.

  That is, the insulated metal base circuit board of the present embodiment has a structure in which the second insulating layer (B) is further provided on the insulating layer (A) 3 and the conductor circuit 2. Therefore, the surface of the conductor circuit 2 is protected by the second insulating layer (B), and is excellent in durability such as moisture resistance, durability and chemical resistance.

  Here, a rectangular shape having the maximum area inscribed on the outer periphery of the circuit surface of the insulating metal base circuit board can be drawn. Note that the maximum rectangular shape that can be taken in the insulated metal base circuit board according to the present embodiment is shown in FIG. 5 when the largest rectangular shape that can be taken in the insulated metal base circuit board is taken. It is preferable that the ratio of the area of the rectangular shape to the whole area of the planar shape of the metal base circuit board is 60% or more. That is, the proportion of the rectangular insulating metal base circuit board is 60% or more, preferably 70% or more, and more preferably 90% or more. As a result, uniform warpage can be induced, and complex warpage can be controlled to eliminate bonding failure of the bonding material in the mounting process.

[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. As for titanium dioxide, anatase type and rutile type are known. However, rutile type is excellent in stability, so photocatalytic action is weak, and 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 conveniently. 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 conductor circuit 2, an opening is provided in advance by masking or the like at a portion corresponding to a joint portion or connector joint portion of an electronic component such as an LED. What is necessary is to respond.

  From the viewpoint of adhesiveness with the insulating layer (B), the surface of the conductor circuit 2 on the side in contact with the insulating layer (B) 6 is subjected to surface treatment such as sandblasting, etching, various plating treatments, and coupling agent treatment. It can be selected as appropriate.

  In the hybrid integrated circuit module having the above-described configuration, the insulating layer (B) 6 is formed on the conductor circuit 2 or the insulating layer (A) 3, and the insulating layer (B) 6 includes LED elements, chip resistors, and chips. When an electronic component such as a 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) 6 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 the metal foil (conductor circuit 2), it is cured by applying light such as ultraviolet rays or heat treatment as necessary, and then the metal foil is subjected to a treatment such as etching. A method for forming a circuit can be applied.

  Alternatively, after a sheet made of an insulating material (corresponding to the insulating layer (A) 3) is prepared in advance and the metal foil 4 or the metal foil that becomes the conductor metal (conductor circuit 2) is pasted through the sheet, A method of forming a circuit by etching or the like 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.

  In this embodiment, from the viewpoint of adhesiveness with the insulating layer (B), the surface of the metal foil constituting the conductor circuit 2 on the side in contact with the insulating layer (B) is sandblasted, etched, various plating treatments, coupling Surface treatment such as agent treatment can be selected as appropriate.

  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>
Hereinafter, the operation and effect of the insulating metal base circuit board according to the first embodiment or the second embodiment and the hybrid integrated circuit module using the insulating metal base circuit board will be described.

  In the insulated metal base circuit boards according to the first embodiment and the second embodiment, a band-shaped region exists along the outer periphery of the circuit surface of the insulated metal base circuit board, and the circuit surface passes through the center of gravity of the circuit surface. The band-like regions in the cross section of any insulating metal base circuit board perpendicular to each other are located at a position away from one end of the circuit surface in the cross section by 0.2 / 100 times the width Ws of the circuit surface in the cross section and at a position separated by 10/100 The area occupied by the conductor circuit 2 in the belt-like region is designed to be 60% or more. Therefore, it is possible to reduce the warping behavior generated by the thermal load during the substrate mounting process, and to firmly bond the bonding material 5 of the electronic component such as solder or conductive resin.

  In addition, the insulating metal base circuit boards according to the first and second embodiments are designed so that the ratio of the rectangular area to the entire area of the circuit surface of the insulating metal base circuit board is 60% or more. May be. According to this configuration, uniform warpage can be induced, and complicated warpage can be controlled to eliminate bonding failure of the bonding material 5 in the mounting process.

  The insulated metal base circuit boards according to Embodiments 1 and 2 may be designed such that the conductor circuit 2 and the metal foil 4 are made of different metal materials or alloy materials. For example, the conductor circuit 2 may be made of copper or a copper alloy, and the metal foil 4 may be made of aluminum or an aluminum alloy. As described above, when the materials of the conductor circuit 2 and the metal foil 4 are different, warping is likely to occur due to a difference in linear expansion coefficient in particular due to a thermal load, but according to the first and second embodiments. This is because the warpage can be reduced by devising a circuit design method like an insulating metal base circuit board.

  The insulated metal base circuit boards according to Embodiments 1 and 2 may be designed such that the insulating layer (A) 3 is made of an insulating resin composition. This is because the insulating layer (A) 3 made of an insulating resin composition is preferable because it is excellent in terms of moldability, flexibility, insulation, and the like.

  The insulated metal base circuit boards according to Embodiments 1 and 2 may be designed such that the thickness of the metal foil 4 is 0.5 mm or less. According to this configuration, since the rigidity of the metal foil 4 is reduced, the structure is likely to be warped due to a thermal load especially in the structure. However, the circuit design method as in the insulated metal base circuit board according to the first and second embodiments. This is because the warpage can be reduced by devising.

In addition, the insulating metal base circuit boards according to the first and second embodiments may be designed such that the area of the planar shape of the insulating metal base circuit board is 6 × 10 ⁴ mm ² or more. Thus, when the area of the planar shape is 6 × 10 ⁴ mm ² or more, the structure is likely to warp due to a thermal load in particular, but the insulating metal base circuit board according to Embodiments 1 and 2 described above. This is because the warpage can be reduced by devising the circuit design method.

  In addition, the insulated metal base circuit boards according to the first and second embodiments are each formed by further providing the second insulating layer (B) 6 on the insulating layer (A) 3 and the conductor circuit 2. May be designed. This is because the surface of the conductor circuit 2 is protected by the second insulating layer (B), thereby improving durability such as moisture resistance, durability and chemical resistance.

  Further, since the hybrid integrated circuit modules according to the first and second embodiments both use the insulating metal base circuit boards according to the first and second embodiments, even if the size of the substrate increases. Or, even if the substrate thickness is reduced, the warping behavior caused by the thermal load during the mounting process can be reduced, and the bonding material for electronic components can be securely bonded, even under actual use, It is possible to provide a hybrid integrated circuit module having a highly reliable characteristic without causing peeling of the peripheral portion.

  In other words, the insulated metal base circuit boards according to the first and second embodiments can reduce the warping behavior caused by the thermal load during the board mounting process, and can be soldered or conductive. Bonding materials for electronic components such as resins can be firmly bonded. Therefore, the insulating metal base circuit board according to the first and second embodiments includes a hybrid integrated circuit on which a semiconductor element, a light emitting diode (LED) element, a surface mounted electronic component such as a chip resistor or a chip capacitor is mounted. It can be suitably applied to a circuit module. In addition, the circuit design method of the insulated metal base circuit board according to the first and second embodiments described above is a circuit design method for reducing the warping behavior caused by the thermal load during the mounting process and a hybrid using the circuit design method. The present invention can also be suitably applied to an integrated circuit module. In addition, the circuit design method for an insulating metal base circuit board according to the first and second embodiments is extremely effective when applied to an insulating metal base circuit board having a small thickness or an insulating metal base circuit board having a large area. .

  Further, the insulating metal base circuit board according to the first and second embodiments includes a case where the insulating layer (A) 3 and the insulating layer (B) 6 are formed on the conductor circuit 2. The insulating layer (B) 6 can also be used as a solder resist for specifying the location of the bonding material when electronic components such as LED elements, chip resistors and chip capacitors are fixed by a bonding material such as solder or conductive resin. it can. Furthermore, the insulating film (B) 6 can be used as a planar light source by using a white film to increase the reflectance with respect to light and combining it with an LED element. The flat light source can be used as various illuminations, and as a backlight for various liquid crystal panels such as a television, a personal computer, and a mobile phone.

  The hybrid integrated circuit module according to the first and second embodiments has a structure in which a plurality of circuits are provided on an insulating metal base circuit board. For example, an LED element or a semiconductor chip is provided on the circuit board. And electronic components such as resistor chips are fixed by a bonding material such as solder or conductive resin, and include the illumination and backlight described above.

  As mentioned above, although embodiment of this invention was described with reference to drawings, these are the illustrations of this invention, Various structures other than the above are also employable.

  For example, in the above-described embodiment, the hybrid integrated circuit module is used while being fixed to a housing, but may be attached to various resin cases made of PPS (polyphenylene sulfide) or the like, or embedded in an epoxy resin or the like. There is also a case. The electronic component may be provided in one circuit, or one electronic component may be provided over two or more circuits.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further, this invention is not limited to these.

<Examples 1-16, Comparative Examples 1-8>
On a copper foil having a thickness of 35 μm, phenol novolak (manufactured by Dainippon Ink & Chemicals, “TD-2131”) is used 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”). )) Is added, and the crushed coarse particles of silicon oxide (manufactured by Tatsumori, “A-1”) having an average particle size of 1.2 μm and the crushed coarse particles having an average particle size of 10 μm are oxidized. Silicon (manufactured by Tatsumori Co., Ltd., “5X”) is combined so that the insulating layer has a volume of 56% by volume (spherical coarse particles and spherical fine particles have a mass ratio of 7: 3), and the thickness after curing is 150 μm. Thus, a coating layer (insulating layer (A) 3) was formed. Next, an aluminum foil (metal foil 4) having a thickness of 200 μm was laminated and heated to cure the coating layer to obtain an insulating metal base substrate.

  Further, with respect to the metal base substrate, a predetermined position is masked with an etching resist and the copper foil is etched, and then the etching resist is removed to form a copper circuit (conductor circuit 2). The maximum rectangle that can be taken in the main surface was an insulating metal base circuit board having a size of 350 mm × 350 mm. Several masks at this time were prepared and used as examples and comparative examples. The pattern of FIG. 1 is Example 4, and the pattern of FIG. For each example and comparative example, Table 1 shows the occupation ratio of the conductor circuit installation area in the belt-shaped area and the ratio of the largest rectangular area to the circuit board main surface area.

  A white solder resist layer (insulating layer (B) 6) was applied on the insulating metal base circuit board, and cured with heat and light. At this time, no white coating film is formed on the bonding material 5 portion on the copper circuit (conductor circuit 2).

  Next, a surface mount type connector of ERNI was joined to the pad of each circuit board obtained by the above operation with the joining material 5 to obtain a hybrid integrated circuit module. In Examples 1 to 12 and Comparative Examples 1 to 6, solder made of tin-copper-silver was used and soldered by reflow at a temperature of 550K. Moreover, about Examples 13-16 and Comparative Examples 7 and 8, the conductive adhesive which consists of silver-epoxy was used, and it joined by the reflow at the temperature of 385K.

(Measurement of warpage)
After bonding, the substrate was placed on a horizontal table and the height of each part of the substrate from the table was measured to obtain the maximum amount of warpage. The results are shown in Table 2.

(Observation of bonding state)
Moreover, after joining, it was observed whether or not the connector solder had any joint failure. The results are shown in Table 2.

(Observation of cracks)
Further, with respect to each of the above hybrid integrated circuit modules, a heat cycle test is performed in which a predetermined number of cycles is performed with 423 K7 minutes held after being held for 233 K7 minutes in the liquid phase, and each hybrid integrated circuit is mainly bonded with an optical microscope after the test. The presence or absence of the generation | occurrence | production of the crack of a part was observed. The results are shown in Table 2.

In Table 2, the meanings of various symbols are as follows.
◎: No abnormality ○: Partially defective or cracked ×: Mostly defective or cracked −: Not implemented

<Discussion>
As can be seen from the results in Table 2, the maximum warpage amounts of Examples 1 to 6 and 13 to 16 were 1/2 or less of those of Comparative Examples 1 to 8, and the hybrid integrated circuit module according to the present invention caused the warpage of the substrate. It is clear that it is excellent in that it can be reduced.

  Further, as can be seen from the results in Table 2, in Comparative Examples 4 to 6, defective bonding was recognized, but in Examples 1 to 16, it was confirmed that there was no abnormality, and the hybrid integrated circuit according to the present invention It is clear that the module is excellent.

  Furthermore, as can be seen from the results in Table 2, in Comparative Examples 1 to 8, cracks were observed, whereas in Examples 1 to 18, it was confirmed that there were few cracks even after 500 heat cycles. It was done. Furthermore, in Examples 1 to 7, it was confirmed that there was no occurrence of cracks even after 500 heat cycles, and it was clear that the hybrid integrated circuit module according to the present invention was excellent in crack resistance. is there.

  In the above, this invention was demonstrated based on the Example. It is to be understood by those skilled in the art that this embodiment is merely an example, and that various modifications are possible and that such modifications are within the scope of the present invention.

  If the circuit design method of the present invention and an insulated metal base circuit board using the circuit design method are used, bonding defects do not occur because the warpage in the mounting process is small. It is possible to provide a highly reliable hybrid integrated circuit module without causing cracks in the bonding material and its peripheral portion, and it is highly reliable and industrially useful.

It is the plane schematic which shows an example of the insulated metal base circuit board based on the Example of this invention. 1 is a schematic cross-sectional view of a hybrid integrated circuit module according to an embodiment of the present invention. It is the plane schematic which shows another example of the insulated metal base circuit board based on the Example of this invention. It is a cross-sectional schematic diagram which shows another example of the hybrid integrated circuit module of this invention. It is a plane conceptual diagram which shows the largest rectangle which can be taken in the insulated metal base circuit board main surface which concerns on the Example of this invention. FIG. 3 is a schematic plan view of a hybrid integrated circuit module according to a comparative example of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Surface mount electronic component 2 Conductor circuit 3 Insulation layer (A)
4 Metal foil 5 Bonding material 6 Insulating layer (B)
Ws Length of the cross section passing through the center of gravity from the edge of the insulating metal base circuit board

Claims (9)

An insulating metal base circuit board in which a conductor circuit is provided on a metal foil via an insulating layer,
A band-shaped region exists along the outer periphery of the circuit surface of the insulating metal base circuit board,
The band-like region in the cross section of any of the insulating metal base circuit boards perpendicular to the circuit plane passing through the center of gravity of the circuit plane is 0. 0 of the width of the circuit plane in the cross section from one end of the circuit plane in the cross section. A region sandwiched between a position separated by 2/100 times and a position separated by 10/100,
An insulating metal base circuit board characterized in that an occupancy ratio of an installation area of the conductor circuit in the belt-shaped area is 60% or more.   The ratio of the area of the rectangular shape with the largest area inscribed in the outer periphery of the circuit surface to the entire area of the circuit surface of the insulating metal base circuit board is 60% or more. Insulated metal base circuit board.   3. The insulated metal base circuit board according to claim 1, wherein the metal foil and the conductor circuit are made of different metal materials or alloy materials.   4. The insulated metal base circuit board according to claim 3, wherein the conductor circuit is made of copper or a copper alloy, and the metal foil is made of aluminum or an aluminum alloy.   5. The insulated metal base circuit board according to claim 3, wherein the insulating layer is made of an insulating resin composition.   6. The insulated metal base circuit board according to claim 1, wherein the metal foil has a thickness of 0.5 mm or less. The insulating metal base circuit board according to claim 1, wherein an area of the planar shape of the insulating metal base circuit board is 2 × 10 ⁴ mm ² or more.   8. The insulating metal base circuit board according to claim 1, further comprising a second insulating layer provided on the insulating layer and the conductor circuit.   A hybrid integrated circuit module comprising the insulating metal base circuit board according to claim 1.

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