JP5030103B2 - Method of manufacturing metal base circuit board for light emitting element and metal base circuit board for light emitting element - Google Patents

Description

  The present invention relates to a method for producing a metal base circuit board for a light-emitting element that is excellent in heat dissipation and further excellent in electric resistance, and a metal base circuit board for a light-emitting element obtained by the method. Furthermore, the present invention relates to a method for producing a metal base circuit board for a light emitting element using the circuit board and a metal base circuit board for a light emitting element obtained by the method.

  In recent years, high density mounting and high performance have been demanded for devices incorporating light emitting elements such as LEDs. As a result of downsizing and higher power of the apparatus in accordance with these requirements, there is a problem of how to dissipate (heat radiate) the heat generated from the light emitting element in a narrow space. There are various approaches to this heat dissipation problem.

  For example, it is known that a thermal via for radiating heat generated from a light emitting element is provided on a circuit board for the light emitting element (Patent Documents 1 to 3).

  Various methods are known for installing thermal vias on circuit boards. (Patent Documents 4 to 6).

JP 2006-86391 A JP 2006-66519 A JP 2005-197633 A Japanese Patent No. 3217381 Japanese Patent No. 3907062 JP 2004-95757 A

  In the conventional method for manufacturing a circuit board for a light emitting element, a thermal via having a large surface area could not be formed in the substrate, so that the heat dissipation of the obtained substrate was not satisfactory.

The inventors of the present invention have made extensive studies on the heat dissipation and productivity of the metal base circuit board for light-emitting elements. As a result, by using an epoxy resin adhesive sheet in a predetermined cured state as an insulating layer, It has been found that vias can be formed in a circuit board, and the obtained circuit board for a light-emitting element is excellent in heat dissipation. The present invention has been made based on this finding.
That is, the present invention
(1) A method for producing a metal base circuit board for a light emitting device,
(I) a step of disposing an adhesive sheet in a B stage state on a metal substrate having one or more vias;
(Ii) a step of further disposing a metal foil on the adhesive sheet disposed on the metal substrate; and
(Iii) including a step of forming a metal base circuit board by integrating a laminate of a metal substrate, an adhesive sheet and a metal foil by heating under pressure until the adhesive sheet is in a C-stage state;
A method wherein the B-staged adhesive sheet is produced from an adhesive sheet-forming composition containing an epoxy resin and a curing agent for the epoxy resin, but not containing an inorganic filler;
(2) The method for producing a metal base circuit board for a light emitting device according to (1) above, wherein the withstand voltage of the adhesive sheet in the C stage state is 500 V or more;
(3) The method for producing a metal base circuit board for a light-emitting element according to any one of (1) to (2), wherein the epoxy resin curing agent is a compound having a hydroxyl group;
(4) The method for producing a metal base circuit board for a light-emitting element according to any one of (1) to (3), wherein the metal substrate has a via surface area of 0.0003 mm ² or more;
(5) The metal base circuit board for a light-emitting element according to any one of (1) to (4), wherein the via of the metal substrate is manufactured by chemical treatment or machining. Production method;
(6) Heating is performed under pressure of the laminate of the metal substrate, the adhesive sheet, and the metal foil so that the via of the metal substrate penetrates the adhesive sheet and the via and the metal foil are electrically connected. The manufacturing method of the metal base circuit board for light emitting elements as described in any one of said (1) thru | or (5);
(7) The manufacturing method of the metal base circuit board for light emitting elements as described in any one of said (1) thru | or (6) whose light emitting element is LED;
(8) A metal base circuit board for a light-emitting element manufactured by the manufacturing method according to any one of (1) to (7);
(9) The metal base circuit board for a light emitting device according to (8), wherein the light emitting device is an LED;
(10) A method of manufacturing a metal base circuit board for a light emitting device,
(I) a step of disposing an adhesive sheet in a B stage state on a metal substrate having one or more vias;
(Ii) a step of further disposing a metal foil on the adhesive sheet disposed on the metal substrate; and
(Iii) Step of forming a metal base circuit board by integrating a laminate of a metal substrate, an adhesive sheet and a metal foil by heating under pressure until the adhesive sheet is in a C-stage state (iv) Processing a metal substrate and / or a metal foil of a metal base circuit board to form a circuit,
A method wherein the B-staged adhesive sheet is produced from an adhesive sheet-forming composition containing an epoxy resin and a curing agent for the epoxy resin, but not containing an inorganic filler;
(11) A metal base circuit board for a light-emitting element manufactured by the manufacturing method according to (10); and (12) The metal base circuit board for a light-emitting element according to (11), wherein the light-emitting element is an LED. It is about.

  INDUSTRIAL APPLICABILITY According to the present invention, a metal base circuit board for a light-emitting element having a thermal via with a large surface area and excellent heat dissipation can be obtained by a simple process, as shown in Examples described later. Furthermore, the obtained metal base circuit board is excellent not only in heat dissipation but also in withstand voltage. Therefore, this invention can provide the metal base circuit board for light emitting elements which is excellent in heat dissipation and withstand voltage property, and the metal base circuit board for light emitting elements which consists of the said circuit board with sufficient productivity.

  Hereinafter, the present invention will be described in detail.

The metal which comprises a metal substrate is aluminum, iron, copper, and these alloys. Aluminum, copper, and alloys thereof are preferable in terms of excellent heat dissipation.
In order to improve the adhesion between the metal substrate and the adhesive sheet, the adhesive surface with the adhesive sheet may be subjected to surface treatment such as degreasing treatment, sand blasting, etching, various plating treatments, and coupling agent treatment.

  The thickness of the metal substrate (referring to the thickness of the flat portion without vias) can be appropriately changed according to the use of the metal base circuit substrate for light emitting elements, but is preferably 0.013 mm to 4 mm. Particularly preferred is .020 mm to 2 mm. Generation | occurrence | production of the wrinkle at the time of handling can be prevented as it is 0.013 mm or more. Although there is no technical limitation on the upper limit value, 4 mm or less is sufficient in view of the practical application of the current metal base circuit board for light emitting elements.

The metal substrate has one or more vias on the adhesive surface side with the adhesive sheet. The via is provided for the purpose of radiating heat generated from the light emitting element, but can also function as a local electrical connection between the metal substrate and the metal foil.
Examples of a method for providing a via on a metal substrate include chemical processing such as plating and etching, and mechanical processing such as an end mill, a milling machine, and a laser. Specific examples include the following preparation methods, but the present invention is not limited to these. These specific methods can also be used in combination.
1. Half-etch the metal substrate.
2. Ni plating is applied to the metal substrate or the metal foil, and copper plating is further provided with a thickness corresponding to the adhesive sheet. A protective film (resist) is provided in a place where a metal pillar is required, and Cu in an unnecessary portion is selectively etched, and further Ni is selectively etched (for metal foil, a plurality of adhesive sheets and a plurality of sheets are formed on one metal substrate. In the case of forming a via in a metal foil sandwiched between adhesive sheets in a circuit board having a multilayer structure in which metal foils are laminated).
3. Machine the metal substrate with an end mill.

  The shape of the via is not particularly limited, but a cylinder or a truncated cone is preferable.

The surface area of the top surface of one via (hereinafter referred to as the surface area) (when the via shape is a cylinder or a truncated cone, this is the total surface area of the via provided on the metal substrate or metal foil minus the side area) is, 0.0003mm ² ~300mm ^2, is preferably 0.003 mm ² to 200 mm ^2, particularly preferably 0.01mm ² ~150mm ^2. When it is 0.0003 mm ² or more, a sufficient function as a thermal via (via for the purpose of improving heat dissipation) can be exhibited, and the shape of the via can be maintained when laminating an adhesive sheet or a metal foil. Sufficient reliability can be exhibited. If it is 300 mm ² or less, the reliability of heat dissipation due to poor contact between the via and the metal foil (caused by residual adhesive sheet between the via and metal foil or uneven contact between the via upper surface and the metal foil) The decrease can be suppressed.

  The height of one via is preferably 0.05 mm to 0.5 mm. More preferably, it is 0.08 mm to 0.4 mm. When the thickness is 0.05 mm or more, sufficient electrical connection between the metal substrate and the metal foil via the via can be achieved. When the thickness is 0.5 mm or less, the thickness of the adhesive sheet can be set to 0.5 mm or less, and sufficient heat dissipation can be obtained.

  An adhesive sheet is manufactured from the composition for adhesive sheet formation containing an epoxy resin and the hardening | curing agent of this epoxy resin.

Any epoxy resin can be used without particular limitation as long as it can be used for a substrate for a metal base circuit for a light emitting element and can provide electrical insulation to a cured body of an adhesive sheet. In addition, the epoxy resin in this specification means the prepolymer before hardening containing the unreacted epoxy group which can react with the below-mentioned hardening | curing agent.
Specific examples include bisphenol type epoxy resin, naphthalene type epoxy resin, phenylmethane type epoxy resin, tetrakisphenolmethane type epoxy resin, and biphenyl type epoxy resin.
Among these, an epoxy resin in which the main chain has a polyether skeleton and is linear is preferable because of excellent stress relaxation after curing. Specific examples include bisphenol A type epoxy resins, bisphenol A alkylene oxide adduct type epoxy resins, bisphenol F type epoxy resins, bisphenol A type hydrogenated epoxy resins, aliphatic epoxy resins (for example, polypropylene glycol type epoxy resins, Polytetramethylene glycol type epoxy resin) and polysulfide-modified epoxy resin.
In the present invention, a single type of epoxy resin may be used alone, or a plurality of types of epoxy resins may be used in combination.

When high heat resistance is required for a metal base circuit board, bisphenol A type epoxy resin can be used alone or in combination with other epoxy resins (for example, aliphatic epoxy resin) to provide high electrical insulation and heat resistance. It is particularly preferable because a cured resin body having high properties can be obtained.
More preferably, the bisphenol A type epoxy resin has an epoxy equivalent of 300 or less. When the epoxy equivalent is 300 or less, a decrease in Tg (that is, a decrease in heat resistance) due to a decrease in the crosslinking density during curing can be prevented.

  More preferably, the bisphenol F type epoxy resin has an epoxy equivalent of 1500 or less. When the epoxy equivalent is 1500 or less, it is possible to prevent a decrease in Tg (that is, a decrease in heat resistance) due to a decrease in crosslink density during curing.

When it is desired to further improve the handling property of the adhesive sheet in the production process of the metal base circuit board, it is preferable to use the aliphatic epoxy resin alone or in combination with another epoxy resin (for example, bisphenol type epoxy resin).
As the aliphatic epoxy resin, a higher alcohol glycidyl ether type can be generally used in consideration of a balance of low elasticity, mechanical properties, heat resistance, handling, and the like. The structure of the higher alcohol glycidyl ether type epoxy resin is not particularly limited, and the higher alcohol portion may be branched, but a structure containing 40 or less alkylene groups or alkenylene groups having a side chain is more preferable. Specific examples include polypropylene glycol type epoxy resins and polytetramethylene glycol type epoxy resins.

  The epoxy resin used in the present invention preferably has a hydrolyzable chlorine concentration of 600 ppm or less. When the hydrolyzable chlorine concentration is 600 ppm or less, sufficient moisture resistance can be exhibited as a metal base circuit board for a light emitting device.

  Any of the above-mentioned epoxy resins is a known substance and can be easily obtained in the market.

Any epoxy resin curing agent can be used without particular limitation as long as it can cure the above-mentioned epoxy resin, but a compound having a hydroxyl group is preferred from the viewpoint of electrical characteristics of the resulting cured product. As a specific example, at least one selected from the group consisting of an amine curing agent, an acid anhydride curing agent, a phenol curing agent, and dicyanamide can be used.
Amine curing agents include aromatic amines (metaphenylenediamine, diaminodiphenylsulfone, diaminodiphenylmethane, etc.), alicyclic amines (isophoronediamine, etc.), aliphatic amines (diethylenetriamine, triethylenetriamine, tetraethylenementamine, etc.) Is mentioned.
Examples of the acid anhydride curing agent include tetrahydrophthalic anhydride, methyl nadic anhydride, hexahydrophthalic anhydride and the like.
Examples of phenolic curing agents include phenol novolac resins and bisphenol A type novolac resins.
Of these, phenol novolac resins, bisphenol A type novolac resins, and dicyanamide are preferable from the viewpoint of controlling the semi-cured state (B stage state) in the production stage.

  All of the above-mentioned curing agents are known substances and can be easily obtained in the market.

  It is preferable that the compounding quantity of the hardening | curing agent of an epoxy resin is 5-60 mass parts with respect to 100 mass parts of epoxy resins, and it is especially preferable that it is 10-50 mass parts.

In order to improve the curing of the epoxy resin, a curing catalyst may be used as necessary.
As the curing catalyst, generally, an imidazole compound (for example, 2,3-dihydro-1H-pyrrolo (1,2-a) benzimidazole), an organic phosphate compound (for example, triphenylphosphine), a tertiary amine, Quaternary ammonium etc. are used and any 1 or more types can be selected.
The addition amount of the curing catalyst can be appropriately set according to the curing temperature, but is generally preferably 0.01 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the epoxy resin. Curing can be sufficiently obtained when the content is 0.01 parts by mass or more. When it is 5 parts by mass or less, rapid curing of the adhesive sheet from the B stage state to the C stage state can be prevented.

In addition, if necessary, various known additives such as a dispersion aid such as a coupling agent and a viscosity adjustment aid such as a solvent may be added.
Further, in order to reinforce the strength of the adhesive sheet, a fibrous reinforcing material such as glass fiber, ceramic fiber, aramid fiber, etc. may be added.

  The adhesive sheet does not contain an inorganic filler. An inorganic filler means the particulate material of the material chosen from the group which consists of a metal, a metal oxide, and a ceramic. Specific examples of the material include silicon oxide (particularly silicon dioxide), aluminum oxide, aluminum nitride, boron nitride, magnesium oxide, silicon nitride, and the like. A particulate matter means a spherical thing, a needle-like thing, a scale-like thing, and a crushed thing. However, the fibrous substance is not included in the particulate matter.

A typical manufacturing method of the adhesive sheet is as follows.
Epoxy resin, epoxy resin curing agent and optional components (curing catalyst and / or various additives) are mixed in advance by a known mixing means (for example, universal stirrer, hybrid mixer, etc.) to form an adhesive sheet forming composition. To do. The obtained composition is coated on the liner with a desired thickness by a known coating means (die coater, comma coater, doctor coater, etc.), heated and semi-cured to the B stage state, and then the obtained sheet is Peel off.

  As the liner, a resin film is preferable because of cost and workability. The resin film is not particularly limited as long as there is no problem in heat resistance when the adhesive sheet is B-staged. Polyethylene (PE), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), biaxially oriented polypropylene (OPP), etc. Can be used. The thickness of the resin film as a liner is generally 0.025 to 0.5 mm. The resin film is preferably subjected to surface treatment such as coating with a silicone resin, fluororesin, or olefin resin, sandblast treatment, corona treatment, plasma treatment and the like in consideration of peelability.

  The temperature at which the B-staged adhesive sheet is obtained varies depending on the type of epoxy resin, curing agent and curing catalyst constituting the adhesive sheet, but a high temperature is preferable because the heating time can be shortened. Specifically, it is preferable to heat at 80 to 200 ° C. If it is 80 ° C. or higher, the heating time required to obtain the B stage state can be shortened. When it is 200 ° C. or lower, the curing speed until the B stage state is achieved can be appropriately controlled.

  As described above, the adhesive sheet may be separately manufactured on a liner before being placed on the metal substrate, but may be manufactured on the metal substrate. That is, the above-mentioned composition for forming an adhesive sheet may be directly applied onto a metal substrate, heated, and semi-cured to a B stage state.

The “B stage state”, which is a term indicating the state of the adhesive sheet, refers to a state where the adhesive sheet is in a dry state at room temperature (25 ° C.) but melts again when heated to a high temperature (80 ° C. or higher).
Specifically, the degree of cure obtained from the following formula using DSC (differential scanning calorimeter) is from 5 to 70%, more preferably from 20 to 65%.

Curing degree (%) = (X−Y) / X × 100
X: Amount of heat generated when DSC is used to cure an adhesive sheet sample that has not been subjected to B-stage state treatment (heat treatment).
Y: The amount of heat measured when the adhesive sheet sample subjected to the B-stage conditioning treatment was cured using DSC.
The “cured” state in the above X and Y can be identified from the peak of the obtained DSC curve.

  The adhesive sheet in the B stage state has an appropriate tackiness for facilitating positioning when the metal foil is disposed thereon. Therefore, the use of the B-staged adhesive sheet can greatly improve the workability in the production of the metal base circuit board.

The “C stage state” refers to a state in which the curing of the adhesive sheet is almost completed and it does not melt again even when heated to a high temperature. Specifically, it means a state in which the degree of cure described in the “B stage state” column exceeds 70%. When confirming the C-stage state, “X” and “Y” in the above formula for calculating the degree of cure are as follows.
X: Amount of heat generated when DSC is used to cure an adhesive sheet sample that has not been subjected to B-stage state treatment (heating treatment) and C-stage state treatment (step (3) described later).
Y: The amount of heat measured when the adhesive sheet sample subjected to the B-stage conditioning process and the C-stage conditioning process was cured using DSC.
The “cured” state in the above X and Y can be identified from the peak of the obtained DSC curve.

  The thickness of the adhesive sheet can be appropriately changed according to the type of metal substrate and metal foil constituting the metal base circuit substrate for light emitting elements, but is preferably 0.05 mm to 0.5 mm. . More preferably, it is 0.05 mm-0.4 mm. When the thickness is 0.05 mm or more, electrical insulation between the metal substrate and the metal foil and heat dissipation of the substrate in the metal base circuit board can be ensured. When the thickness is 0.5 mm or less, the adhesive sheet can be easily produced.

  The metal which comprises the metal foil used for this invention is aluminum, iron, copper, and these alloys like the above-mentioned metal substrate. Aluminum, copper, and alloys thereof are preferable in terms of excellent heat dissipation.

  Although the thickness of metal foil can change suitably according to the use of the metal base circuit board for light emitting elements, 0.013 mm-0.4 mm are preferable and 0.020 mm-0.20 mm are especially preferable. Generation | occurrence | production of the wrinkle at the time of handling can be prevented as it is 0.013 mm or more. Although there is no technical limitation on the upper limit, in view of the practical use of the current metal base circuit board for light emitting elements, a layer for forming a circuit is sufficient if it is 0.4 mm or less.

The metal base circuit board for a light emitting device of the present invention is manufactured by the following steps:
(1) A step of disposing an adhesive sheet in a B stage state on a metal substrate having one or more vias,
(2) a step of further disposing a metal foil on the adhesive sheet disposed on the metal substrate; and
(3) A step of forming a metal base circuit board by integrating a laminate of a metal substrate, an adhesive sheet and a metal foil by heating under pressure until the adhesive sheet is in a C-stage state.

In step (1), an adhesive sheet in a B-stage state is placed on the metal substrate.
The “arrangement” here refers not only to placing a separately produced adhesive sheet on the metal substrate before placing it on the metal substrate, but also directly applying the composition for forming the adhesive sheet onto the metal substrate and heating it. Forming the adhesive sheet directly on the metal substrate.
When disposing the adhesive sheet on the metal substrate, it is preferable to degrease the metal substrate in advance in order to improve the adhesion between the metal substrate and the adhesive sheet.

  In the step (2), a metal foil is further arranged on the adhesive sheet of “the laminate of the metal substrate and the adhesive sheet” obtained in the step (1).

In the above-described steps (1) and (2), “a laminate of a metal substrate, an adhesive sheet, and a metal foil (metal substrate-adhesive sheet-metal foil)” is sequentially applied onto the metal substrate. Although it is manufactured by arranging, “a laminate of an adhesive sheet and a metal foil” is manufactured in advance, and by placing this laminate on a metal substrate, “a metal substrate, an adhesive sheet, and a metal foil. May be produced.
The “laminated product of the adhesive sheet and the metal foil” can be produced by directly applying the above-mentioned composition for forming an adhesive sheet onto the metal foil and heating it to the B stage state.

In step (3), “the laminate of the metal substrate, the adhesive sheet and the metal foil (metal substrate-adhesive sheet-metal foil)” obtained in step (2) is cured until the adhesive sheet is in the C-stage state. Thus, the metal base circuit board is formed by integration. Curing of the adhesive sheet to the C-stage state can be achieved by heating the laminate under pressure.
The heating temperature is not particularly limited as long as the adhesive sheet can be cured from the B stage state to the C stage state, but is preferably 100 ° C to 250 ° C. When it is 100 ° C. or higher, the curing time of the adhesive sheet necessary for integration of the laminate can be shortened (for example, less than 5 hours), and productivity can be improved. A temperature of 150 ° C. or higher is particularly preferable because the curing time can be further shortened. When the heating temperature is 250 ° C. or lower, deterioration of the adhesive sheet (epoxy resin) due to heating can be prevented.
The pressure during heating is not particularly limited as long as the size that can enhance the adhesion between the adhesive sheet and the metal substrate and the metal foil is preferably ^{5kgf / cm 2 ~50kgf / cm 2} . And particularly preferably ^{10kgf / cm 2 ~40kgf / cm 2} . Sufficient adhesiveness is acquired as it is 5 kgf / cm < ² > or more. The thickness of an adhesive sheet can be made uniform as it is 50 kgf / cm < ² > or less.
By heating, the adhesive sheet is cured from the B stage state to the C stage state. At that time, since the adhesive sheet, the metal substrate, and the metal foil are in close contact with each other by pressurization, strong adhesion between the adhesive sheet, the metal substrate, and the metal foil occurs, and “a laminate of the metal substrate, the adhesive sheet, and the metal foil” Integration is achieved.

  By applying pressure within the above-mentioned pressure range, the adhesive sheet is penetrated by vias, and a conductive connection between the metal substrate and the metal foil through the vias is created. It is preferable in terms of improving the degree of freedom.

Said manufacturing method is related with the manufacturing method of the board | substrate for light emitting element metal base circuits which has a structure formed by arrange | positioning one adhesive sheet and one metal foil on one metal board | substrate.
The substrate for a metal base circuit for a light-emitting element of the present invention may have a multilayer structure in which a plurality of adhesive sheets and a plurality of metal foils are laminated on one metal substrate as well as the above-described structure. The multilayer structure of the adhesive sheet and the metal foil can be created by the following process performed between the process (2) and the process (3):
(2-2) A step of further arranging an adhesive sheet on the metal foil of the laminate obtained in the step (2), and (2-3) Further on the adhesive sheet arranged in the step (2-2). The process of arranging a metal foil.
Steps (2-2) and (2-3) may be repeated to achieve further multilayering of the adhesive sheet and the metal foil.
A circuit may be formed on the metal foil sandwiched between the adhesive sheets by using a circuit forming method described later during the step of multilayering the adhesive sheet and the metal foil.

Moreover, the adhesive sheet which comprises the metal base circuit board for light emitting elements has insulation, when it makes it a C stage state. Specifically, the adhesive sheet preferably has a withstand voltage of 500 V or more. When the withstand voltage is 500 V, the electrical reliability of the device obtained by incorporating the light emitting element into the metal base circuit board for a light emitting element of the present invention can be enhanced.
When the metal base circuit board for a light emitting device of the present invention is used for an industrial apparatus to which a high voltage and a high current are applied, the C-staged adhesive sheet preferably has a withstand voltage of 1500 V or more. The withstand voltage can be measured according to the step-up method defined in JIS C 2110.

  The metal base circuit board for a light-emitting element obtained by the manufacturing method of the present invention has high heat dissipation, and can give high reliability to a device using the same. Therefore, the present invention can be suitably used for a device including a large number of light emitting elements having a high calorific value and requiring high reliability, for example, a light emitting element circuit board such as an LED.

  As the light emitting element, an LED that emits high heat during light emission can be suitably used.

  The metal base circuit board for light emitting elements can be made into a circuit board by processing the metal substrate and / or metal foil to form a circuit. Examples of the method for forming a circuit on the metal substrate and the metal foil include chemical processing such as etching, machining such as end mill, milling machine, and laser.

  For example, when the present invention is applied to an LED circuit board, a circuit is formed on the metal base circuit board obtained by the above-described manufacturing method, and an LED circuit board can be formed by mounting and wiring LEDs. it can.

  When a light-emitting element such as an LED is directly mounted on the substrate of the present invention in a non-packaged state, a metal frame having a reflective effect is used to efficiently collect light emitted from the light-emitting element on the front surface of the light-emitting element. Is preferably provided. Examples of the material of the metal frame include aluminum and stainless steel. The installation of the metal frame on the circuit board may be performed via an adhesive (for example, an epoxy-based adhesive or a urethane-based adhesive), or may be performed by a combination of electrolytic plating or etching.

  Moreover, in order to improve the brightness | luminance of the board | substrate which mounts LED, you may provide a highly reflective white film | membrane on the surface of a circuit board. As the white film, at least one or more white pigments selected from the group consisting of zinc oxide, calcium carbonate, titanium oxide (especially titanium dioxide), alumina and smectite are blended with ultraviolet curable resin and / or thermosetting resin. What is formed is preferable. The white film can be installed on the circuit board using a method well known in the art.

  Next, the effects of the present invention will be specifically described by way of examples, but the present invention is not limited to the examples.

Example 1
In this example, the metal base circuit board for light emitting element (LED) shown in FIG. 1 was manufactured.
(1) Manufacture of a metal substrate provided with vias A flat copper plate 1 (thickness: 0.100 mm) as a metal substrate and a heat dissipation via 3 (diameter: 3.0 mm (surface area: 7.1 mm ² )). One cylindrical shape, height: 0.15 mm, and two electrical connection vias 5 (diameter: 0.5 mm (surface area: 0.20 mm ² ), shape: cylindrical shape, height 0.15 mm) are formed by etching. did. Subsequently, the surface provided with the via was subjected to a degreasing treatment. This was used for manufacturing a metal base circuit board for a light emitting device.

(2) Production of Adhesive Sheet Forming Composition Polypropylene glycol type epoxy resin which is an epoxy resin (number of alkylene groups having side chains: 5 to 7; hydrolyzable chlorine concentration: 500 ppm) (manufactured by Sakamoto Pharmaceutical Co., Ltd., “ SR-PTMG "), bisphenol A type epoxy resin (epoxy equivalent: 159; hydrolyzable chlorine concentration: 600 ppm) (manufactured by Japan Epoxy Resin," EP828 "), and bisphenol F type epoxy resin (epoxy equivalent: 848; Hydrolyzable chlorine concentration: 600 ppm) (manufactured by Japan Epoxy Resin, “EP4004P”) was mixed at a ratio (mass ratio) of 35:35:30. For 100 parts by mass of the mixed epoxy resin, 30 parts by mass of a phenol novolac resin (Maywa Kasei Co., Ltd., “H-1”) as a curing agent and a coupling agent (Shin-Etsu Chemical Co., Ltd., “ A composition was prepared by adding 1 part by weight of KBM403 "). Furthermore, 0.5 part by weight of 2,3-dihydro-1H-pyrrolo (1,2-a) benzimidazole (manufactured by Shikoku Kasei Co., Ltd., “TBZ”) as a curing catalyst was added to 100 parts by weight of the epoxy resin mixture. Thus, an adhesive sheet forming composition was produced. Each component was blended using a universal stirrer.

(3) Manufacture of metal base circuit board for light emitting element On the surface with vias of metal substrate 1 obtained in (1), the adhesive sheet forming composition manufactured in (2) is the same as the height of via 3. The adhesive sheet 7 (thickness: 0.15 mm) was formed by direct application and heating at 130 ° C. for 10 minutes. The obtained adhesive sheet 7 had a degree of cure of 62% and was in a B-stage state (measured using DSC (DSC6620 manufactured by SII Technology)). Next, a copper foil 9 (thickness: 0.035 mm) as a metal foil was placed on the adhesive sheet 7. The obtained laminate composed of the copper plate 1, the adhesive sheet 7 and the copper foil 9 was integrated by heating at 150 ° C. for 60 minutes while applying a pressure of 30 kgf / cm ² to produce a metal base circuit board. The adhesive sheet 7 constituting the obtained metal base circuit board had a cure degree of 88% and was in a C stage state.
Circuits were formed by etching on both surfaces of the copper plate 1 and the copper foil 9 of the obtained metal base circuit board. Next, a metal frame 15 (material: stainless steel) was placed with an adhesive 17 (urethane adhesive) on the surface where the adhesive sheet 7 was exposed by etching on the copper foil 9 side.

(Test example)
About the metal base circuit board for light emitting elements of Example 1, (1) Withstand voltage of a circuit board and (2) Circuit board heat dissipation were measured by the method shown below.

(1) Dielectric withstand voltage of metal base circuit board Stepped voltage boosting method specified in JIS C 2110 using a measurement sample of a circular electrode having a diameter of 20 mm by etching a copper foil covering a portion of a copper plate that does not have a heat dissipation via Then, the withstand voltage between the copper plate and the copper foil was measured.

(2) Heat dissipation of metal base circuit board For the metal base circuit board for the light emitting device of Example 1, the LED 11 is mounted on the copper foil 9 immediately above the heat dissipation via 3 (the copper foil and the LED are electrically connected). Then, the wiring 13 was installed to create a metal base circuit board (FIG. 2). The LED 11 was caused to emit light by applying a voltage of 3V to the obtained metal base circuit board for light emitting device, and (i) the temperature of the LED mounting portion and (ii) the copper plate portion immediately below the LED was measured by thermography.

  The measurement results of the above (1) to (2) are shown in Table 1 below.

Table 1

  The metal base circuit board for a light emitting device of Example 1 had a withstand voltage (1500 V or more) that can be sufficiently applied to industrial equipment.

  INDUSTRIAL APPLICATION This invention can be utilized for manufacture of the apparatus incorporating the light emitting element in which high heat dissipation is requested | required.

1 is a vertical sectional view of a metal base circuit board for a light emitting device of Example 1. FIG. FIG. 2 is a vertical cross-sectional view of the metal base circuit board for the light emitting device of Example 1 used for the heat dissipation measurement of the test example.

Explanation of symbols

1 Copper Plate 3 Heat Dissipation Via 5 Electrical Connection Via 7 Adhesive Sheet 9 Copper Foil 11 LED
13 Wiring 15 Metal frame 17 Adhesive 19 White film

Claims (12)

A method of manufacturing a metal base circuit board for a light emitting device,
(1) A step of arranging an adhesive sheet in a B-stage state on a metal substrate having one or more cylindrical thermal vias,
(2) a step of further disposing a metal foil on the adhesive sheet disposed on the metal substrate; and
(3) including a step of forming a metal base circuit board by integrating a laminate of a metal substrate, an adhesive sheet, and a metal foil by heating under pressure until the adhesive sheet is in a C-stage state;
The B-staged adhesive sheet is produced from an adhesive sheet-forming composition containing an epoxy resin and a curing agent for the epoxy resin, but not containing an inorganic filler.   2. The method for manufacturing a metal base circuit board for a light emitting device according to claim 1, wherein the withstand voltage of the adhesive sheet in the C stage state is 500 V or more.   The method for producing a substrate for a metal base circuit for a light-emitting element according to any one of claims 1 to 2, wherein the epoxy resin curing agent is a compound having a hydroxyl group. The method for producing a metal base circuit board for a light-emitting element according to any one of claims 1 to 3, wherein the surface area of the cylindrical thermal via of the metal board is 0.0003 mm ² or more. The method for manufacturing a metal base circuit board for a light-emitting element according to any one of claims 1 to 4, wherein the columnar thermal via of the metal substrate is produced by chemical treatment or machining. The heating under pressure the laminate of the metal substrate and the adhesive sheet and the metal foil, so that a cylindrical thermal via of the metal substrate through the adhesive sheet, and said columnar thermal via and the metal foil is electrically connected The manufacturing method of the board | substrate for metal base circuits for light emitting elements as described in any one of Claims 1 thru | or 5 performed to this.   The manufacturing method of the metal base circuit board for light emitting elements as described in any one of Claims 1 thru | or 6 whose light emitting elements are LED.   A substrate for a metal base circuit for a light emitting device, produced by the production method according to claim 1.   The light emitting element metal base circuit board according to claim 8, wherein the light emitting element is an LED. A method of manufacturing a metal base circuit board for a light emitting device,
(1) A step of arranging an adhesive sheet in a B-stage state on a metal substrate having one or more cylindrical thermal vias,
(2) a step of further disposing a metal foil on the adhesive sheet disposed on the metal substrate; and
(3) Step of forming a metal base circuit board by integrating a laminate of a metal substrate, an adhesive sheet and a metal foil by heating under pressure until the adhesive sheet is in a C-stage state (4) Processing a metal substrate and / or a metal foil of a metal base circuit board to form a circuit,
The B-staged adhesive sheet is produced from an adhesive sheet-forming composition containing an epoxy resin and a curing agent for the epoxy resin, but not containing an inorganic filler.   The metal base circuit board for light emitting elements manufactured by the manufacturing method of Claim 10.   The metal base circuit board for light emitting elements of Claim 11 whose light emitting elements are LED.

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